54 results on '"Gunalan A"'
Search Results
2. One-Step Enhancer: Deblurring and Denoising of OCT Images
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Shunlei Li, Muhammad Adeel Azam, Ajay Gunalan, and Leonardo S. Mattos
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optical coherence tomography ,image enhancement ,generative adversarial network ,unsupervised learning ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Optical coherence tomography (OCT) is a rapidly evolving imaging technology that combines a broadband and low-coherence light source with interferometry and signal processing to produce high-resolution images of living tissues. However, the speckle noise introduced by the low-coherence interferometry and the blur from device motions significantly degrade the quality of OCT images. Convolutional neural networks (CNNs) are a potential solution to deal with these issues and enhance OCT image quality. However, training such networks based on traditional supervised learning methods is impractical due to the lack of clean ground truth images. Consequently, this research proposes an unsupervised learning method for OCT image enhancement, termed one-step enhancer (OSE). Specifically, OSE performs denoising and deblurring based on a single step process. A generative adversarial network (GAN) is used for this. Encoders disentangle the raw images into a content domain, blur domain and noise domain to extract features. Then, the generator can generate clean images from the extracted features. To regularize the distribution range of retrieved blur characteristics, KL divergence loss is employed. Meanwhile, noise patches are enforced to promote more accurate disentanglement. These strategies considerably increase the effectiveness of GAN training for OCT image enhancement when used jointly. Both quantitative and qualitative visual findings demonstrate that the proposed method is effective for OCT image denoising and deblurring. These results are significant not only to provide an enhanced visual experience for clinicians but also to supply good quality data for OCT-guide operations. The enhanced images are needed, e.g., for the development of robust, reliable and accurate autonomous OCT-guided surgical robotic systems.
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- 2022
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3. Web crippling capacities of fastened aluminium lipped channel sections subjected to one-flange loading conditions
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Husam Alsanat, Shanmuganathan Gunalan, Hong Guan, and Keerthan Poologanathan
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Computer science ,business.industry ,Structural system ,0211 other engineering and technologies ,chemistry.chemical_element ,020101 civil engineering ,02 engineering and technology ,Building and Construction ,Structural engineering ,Flange ,Finite element method ,0201 civil engineering ,chemistry ,Buckling ,Aluminium ,visual_art ,021105 building & construction ,Architecture ,Aluminium alloy ,visual_art.visual_art_medium ,Safety, Risk, Reliability and Quality ,business ,Civil and Structural Engineering ,Communication channel ,Parametric statistics - Abstract
Recently, a new generation of roll-formed aluminium sections have been produced by BlueScope Permalite Australia and utilized in structural systems. However, limited research has been conducted to investigate their buckling instabilities including web crippling failure. The empirical nature of the current design guidelines may also lead to inaccurate estimation to their web crippling capacities. Therefore, this study aims to investigate the web crippling behaviour of and the design considerations for roll-formed aluminium lipped channel (ALC) sections using a combination of experimental study and finite element analysis (FEA). In total, 40 ALC specimens were tested under one-flange loading conditions with flanges being restrained to the supports (Fastened). Non-linear finite element models were also developed and validated against the experiments. An extensive parametric study was subsequently conducted to extend the range of geometrical dimensions and aluminium alloy grades of ALC sections. Further, the applicability and accuracy of the design rules given in the American, Australian, and European specifications were assessed. It was found that most of these guidelines yield either unconservative or over-conservative predictions of the ultimate web crippling capacities, and hence suitable modifications were proposed. Predictions due to the modified design rules showed a good agreement with both experimental and numerical results, and are hence recommended to be incorporated in relevant aluminium standards.
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- 2021
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4. Effect of electrode substrate and poly(acrylamide) hydrogel electrolytes on the electrochemical performance of supercapacitors
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Sachin Sharma Ashok Kumar, Surender Gunalan, Shahid Bashir, Maryam Hina, Fathiah Kamarulazam, K. P. Ramesh, and S. Ramesh
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Supercapacitor ,Materials science ,General Chemical Engineering ,General Engineering ,General Physics and Astronomy ,Electrolyte ,Lithium acetate ,Electrochemistry ,Dielectric spectroscopy ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Self-healing hydrogels ,Electrode ,General Materials Science ,Cyclic voltammetry - Abstract
In this research, poly(acrylamide) hydrogels were produced by means of free radical mechanism. Lithium acetate with different weight percentages (wt.%) such as 10 wt.%, 20 wt.%, 30 wt.%, and 40 wt.% as a source of mobile ions were incorporated into the hydrogel, and the samples were labeled as LAM1, LAM2, LAM3, and LAM4, respectively. The electrochemical impedance spectroscopy (EIS) revealed that LAM4 hydrogel electrolyte achieved the highest ionic conductivity of 9.45 × 10−3 Scm−1 with lowest activation energy (0.038 eV) at ambient temperature. The electrochemical performance of the fabricated supercapacitors using optimized LAM4 hydrogel electrolyte and different conducting substrates namely graphite foil, nickel foam, and carbon cloth was analyzed. The cyclic voltammetry and galvanic charge–discharge analyses reported that EDLC with carbon cloth resulted in maximum specific capacitance of 198.64 F g−1 at 5 mV s−1 and 439.87 F g−1 at 500 mA g−1, respectively.
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- 2021
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5. Bearing behaviour of aluminium sub-heads with removable beads in façade systems
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Balachandren Baleshan, Hong Guan, Shanmuganathan Gunalan, Benoit P. Gilbert, and Masoumeh Akbari
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Materials science ,0211 other engineering and technologies ,chemistry.chemical_element ,020101 civil engineering ,02 engineering and technology ,Bead ,0201 civil engineering ,law.invention ,Steel design ,law ,Aluminium ,021105 building & construction ,Architecture ,Bearing capacity ,Transom ,Mullion ,Safety, Risk, Reliability and Quality ,Civil and Structural Engineering ,Bearing (mechanical) ,business.industry ,Building and Construction ,Structural engineering ,chemistry ,visual_art ,visual_art.visual_art_medium ,Facade ,business - Abstract
Occupying a substantial proportion of the overall building expense, building envelopes are the subject of ongoing research and improvement in both aesthetic and structural aspects. The aluminium window wall frame, consisting of vertical members (mullions) and horizontal members (head and sill transoms), is placed between sub-heads at the top and sub-sills at the bottom of the wall. These window walls are designed to carry lateral wind loads. Of particular importance to design stability is the bearing behaviour of aluminium sub-heads. The bearing behaviour and capacities of C-shaped sub-heads were recently investigated through a detailed experimental study at Griffith University for the development of strength prediction equations. To allow for easier assembly of facade panels, a kind of sub-head section known as sub-head with removable bead is used in aluminium window wall system. Two parts of this sub-head are connected together without any external mechanisms. The present research places emphasis on assessing the bearing behaviour of aluminium sub-heads with removable beads through comprehensive experimental testing. A total of 36 tests were conducted using six section geometries, two engagement lengths, and three bearing widths. The bearing strengths obtained from tests of aluminium sub-heads with removable beads were compared with the bearing capacities predicted using the design rules developed by the authors for conventional C-shaped aluminium sub-heads and available cold-formed steel design provisions (AISI S240 2015, TI 809-07, and SSMA 2000 specifications). As a result of the investigation, the current design equations were found to be unreliable for estimating the bearing capacity of aluminium sub-head sections with removable beads. Hence, new design expressions have been developed which accurately predict the strengths of aluminium sub-heads with removable beads under out-of-plane loads. Furthermore, the influence of the removable beads on the bearing behaviour and capacity is discussed in detail.
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- 2021
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6. Impact of Foliar Nutrition of Micronutrients on the Morphometric and Qualitative Traits of Annual Moringa (Moringa oleifera): The Miracle Tree
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Swaminathan Venkatesan, Sandeep Gunalan, and Vijayalatha Kulandaivelu Rathnasamy
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chemistry.chemical_classification ,food and beverages ,Plant Science ,Biology ,Micronutrient ,Ascorbic acid ,Moringa ,Plant ecology ,Horticulture ,Point of delivery ,Nutrient ,chemistry ,Agronomy and Crop Science ,Carotenoid ,Food Science ,Panicle - Abstract
The objective of the research was to discern the impact of micronutrients as a foliar spray in annual moringa (Moringa oleifera Lam.) var. PKM 1. The plants were sprayed at three different phases—vegetative, flowering and pod setting phase with micronutrients singly or in combination of ferrous sulphate + citric acid, boric acid, zinc sulphate, manganese sulphate or a mixture of all. The experimental results revealed that all treatments performed significantly better when compared to control with respect to all morphological and yield attributes. The maximum plant height, number of primary branches, number of flowers per panicle, number of panicles per tree, fruit setting percentage, pod yield per tree, protein, ascorbic acid, carotenoid content and micronutrients status in leaves and pods were recorded highest in T8 (FeSO4 1% + Citric Acid 0.1%) + ZnSO4 0.5% + MnSO4 0.5% + H3BO3 0.2%) (micronutrient mixture) than other treatment combinations. The research has proven that the foliar spray of these micronutrient combinations increased the growth, quality and yield of annual moringa var. PKM-1 significantly. The research outcome is in corroboration that the nutrient status of moringa leaves is found to be higher when compared to the pods. Hence, the consumption of moringa leaves will be more beneficial than the pods in terms of nutrient supplement to alleviate malnutrition and sustain nutritional security.
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- 2021
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7. Clinical profiles and risk factors for early and medium-term mortality following heart transplantation in a pediatric population: A single-center experience
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K Suresh Kumaran, Pradeep Gnansekharan, Gunalan Sellamuthu, Kemundel Genny Suresh Rao, Jagdish Dhushyanthan, Komarakshi R. Balakrishnan, Senthil Mettur, Mohan Rajam, Murali Krishna Tanguturu, Ajay Arvind, K. Ramasubramanian, Veena Ramanan, Ganapathy Subramaniam, and Ravikumar Ratnagiri
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medicine.medical_specialty ,medicine.medical_treatment ,Pediatric heart transplant India ,Pediatric Heart transplant ,030204 cardiovascular system & hematology ,Single Center ,pediatric heart transplant Outcomes ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Internal medicine ,Medicine ,Organ donation ,Heart transplantation ,Creatinine ,business.industry ,Hazard ratio ,Transplantation ,medicine.anatomical_structure ,030228 respiratory system ,chemistry ,Pediatrics, Perinatology and Child Health ,Circulatory system ,Vascular resistance ,Original Article ,Cardiology and Cardiovascular Medicine ,business - Abstract
Aims and Objectives: There is a paucity of data regarding the outcomes of Heart transplantation in children from the Indian subcontinent. The data of patients under the age of 18 undergoing an isolated heart transplantation was analyzed for patient clinical profiles and risk factors for early and medium-term mortality. Hospital mortality was defined as death within 90 days of transplantation and medium-term survival as follow up of up to 6 years. Materials and Methods: A total of 97 patients operated between March 2014 and October 2019 were included in this study .Data was collected about their INTERMACS status, pulmonary vascular resistance, donor heart ischemic times, donor age, donor to recipient weight ratio and creatinine levels. Results: The age range was from 1 to 18 with a mean of 10.6 ± 4.6 years. 67 % patients were in INTERMACS category 3 or less.12 children were on mechanical circulatory support at the time of transplant. The 90 day survival was 89 %.The risk factors for hospital mortality was lower INTERMACS category (odd’s ratio 0.2143, P = 0.026), elevated creatinine (odd’s ratio 5.42, P = 0.076) and elevated right atrial pressure ( odd’s ratio 1.19, P = 0.015).Ischemic time, pulmonary vascular resistance (PVR) and PVR index (PVRI) had no effect on 90 day survival. Kaplan Meier estimates for 5 year survival was 73 %.The medium term survival was affected by INTERMACS category (Hazard ratio 0.7, P = .078) , donor age > 25 ( Hazard ratio 1.6, P = 0.26) and raised serum creatinine values.(Hazard ratio 2.7, P = 0.012). All the survivors are in good functional class. Conclusions: Excellent outcomes are possible after heart transplantation in a pediatric population even in a resource constrained environment of a developing economy. More efforts are needed to promote pediatric organ donation and patients need to be referred in better INTERMACS category for optimal outcomes.
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- 2021
8. Shear design rules for roll-formed aluminium lipped channel beams
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Shanmuganathan Gunalan, Milad Rouholamin, Hassan Karampour, and Keerthan Poologanathan
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Materials science ,business.industry ,0211 other engineering and technologies ,chemistry.chemical_element ,020101 civil engineering ,02 engineering and technology ,Building and Construction ,Structural engineering ,Rafter ,Finite element method ,0201 civil engineering ,Corrosion ,Shear (sheet metal) ,chemistry ,Buckling ,Aluminium ,021105 building & construction ,Architecture ,Safety, Risk, Reliability and Quality ,business ,Roof ,Beam (structure) ,Civil and Structural Engineering - Abstract
Aluminium sections are significantly used as primary load bearing members in the building industry due to its corrosion resistance, ease of fabrication and erection, and high strength-to-weight ratio. Roll-formed aluminium lipped channel beam (LCB) is one of these sections which are typically used as roof purlins, floor joists and rafter. However, LCBs are vulnerable to buckling failures due to the increased web slenderness and low elastic modulus compared to steel. Hence an experimental study was conducted at Griffith University to investigate the shear behaviour of these sections. Finite element models of aluminium LCBs were then developed and validated with test results. A detailed parametric study was also undertaken with different sections, web slenderness, aluminium grades and aspect ratios to obtain the shear strengths and shear buckling characteristics of aluminium LCBs. The ultimate shear capacities of aluminium LCBs obtained from the tests and finite element analyses (FEA) were compared with the current shear design rules of Australian/New Zealand Standard and Eurocode for both aluminium structures and cold-formed structures as well as direct strength method (DSM). The comparison showed that these current shear design rules are not suitable to predict the shear capacities of aluminium LCBs. Hence new design rules were proposed in this study to accurately predict the shear capacities of roll-formed aluminium LCBs. This paper presents the details of the experimental and numerical studies and the development of shear design rules based on Australian/New Zealand Standard, Eurocode and DSM.
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- 2020
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9. Insights of structure-based pharmacophore studies and inhibitor design against Gal3 receptor through molecular dynamics simulations
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Gugan Kothandan, Balaji Kannappan, A. Suvitha, Sekar Kanagaraj, Somarathinam Kanagasabai, Sailapathi Ananthasri, Gunalan Seshan, and S. M. Jaimohan
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0303 health sciences ,Chemistry ,030303 biophysics ,Quantitative Structure-Activity Relationship ,General Medicine ,Computational biology ,Molecular Dynamics Simulation ,Ligands ,Molecular Docking Simulation ,03 medical and health sciences ,Molecular dynamics ,Structural Biology ,Structure based ,Homology modeling ,Pharmacophore ,Receptor ,Molecular Biology ,Protein Binding ,G protein-coupled receptor - Abstract
Our present work studies the structure-based pharmacophore modeling and designing inhibitor against Gal3 receptor through molecular dynamics (MD) simulations extensively. Pharmacophore models play a key role in computer-aided drug discovery like in the case of virtual screening of chemical databases, de novo drug design and lead optimization. Structure-based methods for developing pharmacophore models are important, and there have been a number of studies combining such methods with the use of MD simulations to model protein’s flexibility. The two potential antagonists SNAP 37889 and SNAP 398299 were docked and simulated for 250 ns and the results are analyzed and carried for the structure-based pharmacophore studies. This helped in identification of the subtype selectivity of the binding sites of the Gal3 receptor. Our work mainly focuses on identifying these binding site residues and to design more potent inhibitors compared to the previously available inhibitors through pharmacophore models. The study provides crucial insight into the binding site residues Ala2, Asp3, Ala4, Gln5, Phe24, Gln79, Ala80, Ile82, Tyr83, Trp88, His99, Ile102, Tyr103, Met106, Tyr157, Tyr161, Pro174, Trp176, Arg181, Ala183, Leu184, Asp185, Thr188, Trp248, His251, His252, Ile255, Leu256, Phe258, Trp259, Tyr270, Arg273, Leu274 and His277, which plays a significant role in the conformational changes of the receptor and helps to understand the inhibition mechanism. Communicated by Ramaswamy H. Sarma
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- 2020
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10. Proposing the Promiscuous Protein Structures in JNK1 and JNK3 for Virtual Screening in Pursuit of Potential Leads
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Kanagasabai Somarathinam, Sekar Kanagaraj, Ananthasri Sailapathi, Gugan Kothandan, Rahul Jagadeesan, Niyaz Yoosuf, Seshan Gunalan, and Gopinath Murugan
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Virtual screening ,Computer science ,General Chemical Engineering ,Protein Data Bank (RCSB PDB) ,General Chemistry ,computer.file_format ,Computational biology ,Protein Data Bank ,Article ,Chemistry ,Protein structure ,Research community ,QD1-999 ,computer - Abstract
Over the past decade, the available crystal structures have almost doubled in Protein Data Bank (PDB) providing the research community with a series of similar crystal structures to choose from for future docking studies. With the steady growth in the number of high-resolution three-dimensional protein structures, ligand docking-based virtual screening of chemical libraries to a receptor plays a critical role in the drug discovery process by identifying new drug candidates. Thus, identifying potential candidates among all the available structures in a database for docking studies is of utmost importance. Our work examined whether one could use the resolution of a number of known structures, without considering other parameters, to choose a good experimental structure for various docking studies to find more useful drug leads. We expected that a good experimental structure for docking studies to be the one that gave favorable docking with the largest number of ligands among the experimental structures to be selected. We chose three protein test systems for our study, all belonging to the family of MAPK: (1) JNK1, (2) JNK2, and (3) JNK3. On analysis of the results, the best resolution structures showed significant variations from the expected values in their result, whereas the poor resolution structures proved to be better candidates for docking studies.
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- 2020
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11. Numerical investigation of web crippling in fastened aluminium lipped channel sections under two-flange loading conditions
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Hong Guan, Konstantinos Daniel Tsavdaridis, Keerthan Poologanathan, Husam Alsanat, and Shanmuganathan Gunalan
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Bearing (mechanical) ,business.industry ,Computer science ,Acquired web ,chemistry.chemical_element ,Building and Construction ,Structural engineering ,Flange ,law.invention ,TA ,chemistry ,Aluminium ,law ,Architecture ,5052 aluminium alloy ,Safety, Risk, Reliability and Quality ,business ,Civil and Structural Engineering ,Parametric statistics ,Communication channel - Abstract
Aluminium alloys have recently been utilised in the fabrication of thin-walled members using a roll-forming technique to produce purlins, floor joists and other structural bearers. Such members are often subjected to transversely concentrated loads which may possibly cause a critical web crippling failure. Aluminium specifications do not explicitly provide clear design guidelines for roll-formed members subjected to web crippling actions. Therefore, this study was conducted to investigate the mechanism of web crippling for roll-formed aluminium lipped channel (ALC) sections with flanges attached to supports (fastened) under two-flange loading conditions. Based on the experimental works presented in a companion paper, numerical simulations were conducted including an extensive parametric study covering a wide range of ALC geometrical dimensions, bearing lengths, and 5052 aluminium alloy grade with H32, H36 and H38 tempers. The acquired web crippling data were then used to investigate the influence of the flange restraints on the web crippling mechanism of the ALC sections. Furthermore, a detailed assessment of the consistency and reliability of the currently available design rules used in practice was carried out. The predictions of the web crippling design guidelines given in the Australian, American and European specifications were found to be unsafe and unreliable, whereas a good agreement was obtained between the predictions of our recently proposed design guidelines and acquired web crippling results. Further a suitable Direct Strength Method (DSM)-based design approach was developed in this study with associated equations to predict the elastic bucking and plastic loads of fastened ALC sections under two-flange loading conditions.
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- 2020
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12. Coral-like structured nickel sulfide-cobalt sulfide binder-free electrode for supercapattery
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K. P. Ramesh, Che Zhi Kang, Fatin Saiha Omar, S. Ramesh, and Surender Gunalan
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chemistry.chemical_classification ,Materials science ,Nickel sulfide ,Sulfide ,General Chemical Engineering ,General Engineering ,General Physics and Astronomy ,chemistry.chemical_element ,02 engineering and technology ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Cobalt sulfide ,Hydrothermal circulation ,0104 chemical sciences ,chemistry.chemical_compound ,Nickel ,chemistry ,Chemical engineering ,Electrode ,General Materials Science ,0210 nano-technology - Abstract
High-efficiency and lightweight electrodes are advantageous for acquiring high-energy density and flexible supercapattery. Herein, binder-free electrodes were fabricated by growing directly nickel sulfide (NiS) nanoflakes and coral-like nickel sulfide-copper sulfide (NiCuS) on nickel foam using hydrothermal method. Structural studies show that both electrodes are composed of multiphases crystalline structure. Morphological studies reveal that the incorporation of Cu ion has greatly influenced the morphology of NiS, i.e., from nanoflake arrays to coral-like structure (built by interconnected nanotubular). The electrochemical studies demonstrate that the presence of Cu in NiCuS significantly improved the specific capacity of NiS from 382 to 688 C/g at 10 A/g. Moreover, the rate capability of NiS is enhanced from 69 to 78% capacity retention. The origin of the enhancement in performance shown by NiCuS as compared with NiS is due to the enhancement in electroactive sites and reduced internal resistance contributed from the presence of different valence states. In order to access the real-time performance of NiCuS electrode, supercapattery was assembled. The device exhibits the energy density of 23 Wh/kg at 388 W/kg and degraded only 16% of its initial capacity after 5000 cycles.
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- 2020
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13. Preparation and Characterization of Activated Carbons from Parthenium biomass by Physical and Chemical Activation Techniques
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Rajeshwari Sivaraj, Venckatesh Rajendran, and G. Sangeetha Gunalan
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Chemistry ,QD1-999 - Abstract
Parthenium hysterphorous (Linn), a perennial weed of no known beneficial use was introduced as a containment of food grains imported from US with P1480 scheme. The colonization efficiency of the weed was much higher than other indigenous weeds resulting in the reduction of cultivable areas of agricultural lands. Therefore, attention was focused to find out the potential use of its biomass. In the present study the preparation and characterization of activated carbons by physical and chemical activation methods are reported and aims to prepare relatively well developed porous activated carbons as well as study various conditions and parameters that were involved during the process. Among the carbons prepared Zncl2 impregnated carbon at the ratio of 1 was found to possess the characteristic features of an efficient adsorbent. Experimental results showed that pyrolytic and activation conditions leading to various final average temperatures had significant effect on the properties of activated carbons prepared.
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- 2010
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14. Experimental study of aluminium lipped channel sections subjected to web crippling under two flange load cases
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Hong Guan, Poologanathan Keerthan, Shanmuganathan Gunalan, Husam Alsanat, and John Bull
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Bearing (mechanical) ,Computer science ,business.industry ,Mechanical Engineering ,chemistry.chemical_element ,020101 civil engineering ,02 engineering and technology ,Building and Construction ,Structural engineering ,Flange ,0201 civil engineering ,law.invention ,020303 mechanical engineering & transports ,0203 mechanical engineering ,chemistry ,Buckling ,Aluminium ,law ,visual_art ,Aluminium alloy ,visual_art.visual_art_medium ,business ,Civil and Structural Engineering ,Communication channel ,Building construction - Abstract
The application of aluminium alloy members in building construction has considerably increased in recent years due to their appealing advantages such as corrosion resistance and high strength-to-weight ratio. However, the elastic modulus of aluminium is only one-third of that of steel, making aluminium members being susceptible to various buckling modes including web crippling. To date, only a limited amount of research study has been conducted to investigate the web crippling failure phenomenon in aluminium structural members, and no research has been carried out on the web crippling behaviour of roll-formed aluminium lipped channel sections. Hence, an experimental study was conducted to assess the web crippling behaviour and capacities of unfastened aluminium lipped channel sections under two flange load cases (End-Two-Flange (ETF) and Interior-Two-Flange (ITF)). Forty tests were performed with different bearing lengths, web heights and thicknesses. The results obtained from this study were then compared with the nominal web crippling strengths predicted using the design rules provided by the Australian, European and American Standards. The comparison showed that the current design equations are potentially unsafe and unreliable to estimate the capacity for aluminium lipped channel sections under both ETF and ITF load cases. Hence, suitable modifications were proposed to the available design equations based on the experimental results to accurately predict the web crippling capacities of aluminium lipped channel sections. Generally, it is shown that the web crippling results acquired from the modified equations agreed well with the test results.
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- 2019
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15. Chemical composition, structural features, surface morphology and bioactivities of chitosan derivatives from lobster (Thenus unimaculatus) shells
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B. Gunalan, Gopal Prabakaran, Balu Arasukumar, and Meivelu Moovendhan
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Magnetic Resonance Spectroscopy ,Anomer ,Chemical Phenomena ,Chitin ,02 engineering and technology ,Biochemistry ,Antioxidants ,Chitosan ,Structure-Activity Relationship ,03 medical and health sciences ,chemistry.chemical_compound ,Structural Biology ,Glucosamine ,Spectroscopy, Fourier Transform Infrared ,Animals ,Molecular Biology ,Chemical composition ,030304 developmental biology ,0303 health sciences ,Chemistry ,General Medicine ,Carbon-13 NMR ,021001 nanoscience & nanotechnology ,Nephropidae ,carbohydrates (lipids) ,Yield (chemistry) ,Proton NMR ,0210 nano-technology ,Nuclear chemistry - Abstract
The chemical composition, structural features and bioactivities of chitosan derivatives were studied and reported here. Chitin and chitosan was extracted by chemical methods and yield was recorded 35% and 41%, moisture and ash has showed 7.4, 0.73, 1.2 and 0.79% and Ca was recorded high level (590 ppm). The IR spectrum has showed NH primary and secondary amines, OH group and several sugar stretching. N-acetyl glucosamine (GlcNAc), H-2 proton of glucosamine (GlcN), Anomeric protons, H-1 [GlcN (H-1D), GlcNAc (H-1A)] were noticed in 1H NMR and anomeric, methyl carbon atoms in 13C NMR. Rough surface, irregular block, crystalline with cluster and porosity structure was noticed by SEM observation. Antioxidant effect has showed good and concentration depended in four antioxidant assays. The α-amylase and β-glucosidase enzyme inhibition effect of chitosan has showed promising and dose depend also anticoagulant potential. Chitosan could be used in pharmaceutical industry and tissue engineering.
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- 2019
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16. Application of docking and active site analysis for enzyme linked biodegradation of textile dyes
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Gugan Kothandan, Senthil Kumar Sadasivam, Shantkriti Srinivasan, Gnanendra Shanmugam, and Seshan Gunalan
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010504 meteorology & atmospheric sciences ,Health, Toxicology and Mutagenesis ,Bacillus ,Wastewater ,010501 environmental sciences ,Toxicology ,01 natural sciences ,Anthraquinone ,Water Purification ,chemistry.chemical_compound ,Bioremediation ,Catalytic Domain ,NADH, NADPH Oxidoreductases ,Coloring Agents ,0105 earth and related environmental sciences ,chemistry.chemical_classification ,Laccase ,Molecular Structure ,biology ,Active site ,General Medicine ,Nitroreductases ,Biodegradation ,Pollution ,Combinatorial chemistry ,Aeromonas hydrophila ,Molecular Docking Simulation ,Biodegradation, Environmental ,Enzyme ,chemistry ,Docking (molecular) ,Textile Industry ,biology.protein ,Phthalocyanine ,Water Pollutants, Chemical - Abstract
Growth of textile industries led to production of enormous dye varieties. These textile dyes are largely used, chemically stable and easy to synthesize. But they are recalcitrant and persist as less biodegradable pollutants when discharged into waterbodies. Potential use of enzyme-linked bioremediation of textile dyes will control their toxicity in waterbodies. Bioinformatics and Molecular docking tool provides an insight into remediation mechanism by predicting susceptibility of dye degradation using oxidoreductive enzymes. In this study, six dyes, Reactive Red F3B, Remazol Red RGB, Joyfix Red RB, Joyfix Yellow MR, Remazol Blue RGB and Turquoise CL-5B of azo, anthraquinone and phthalocyanine molecular class were identified as potential targets for degradation by laccase and azoreductase of Aeromonas hydrophila in addition to Lysinibacillus sphaericus through in silico docking tool BioSolveIT-FlexX. Azoreductase breaks azo bonds by ping-pong mechanism whereas laccase decolorizes dyes by free radical mechanism which is not specific in nature. Results were analyzed based on parameters like stability, catalytic action and selectivity for enzyme-dye interactions. Amino acids of enzymes interacted with several dyes substantiating variations in active site for enzyme-ligand binding affinity. This suggests the role of enzymes in decolorizing an extensive variety of textile dyes, thereby, aiding in understanding the enzyme mechanisms in Bioremediation.
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- 2019
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17. POTENTIAL NATURAL PRODUCTS WITH ANTICANCER PROPERTIES AND THEIR APPLICATIONS
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Balabhaskar R, Gayathri Gunalan, Rajendra Kumar A, Selvarajan S, and A. Faridha
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Pharmacology ,Chemistry ,Pharmaceutical Science ,Pharmacology (medical) ,Biochemical engineering ,Natural (archaeology) - Abstract
Natural products continue to be a source for the discovery of drugs and drug leads even from ancient period. 80% of drug molecules have been obtained from either natural products or derivatives of the natural product. It has been found that the concept of a single drug for treating single disease may become outdated in the near future and the need of polyherbal formulations, as an alternate remedy is under investigation. Medicinal and aromatic plants contain biologically important phytochemicals, which have known curative properties. They are found as secondary metabolites in plants. Plants also contain certain other compounds that moderate the effects of the active ingredients. Medicinal and aromatic plants have their own contribution toward the treatment of both noncommunicable and communicable diseases. A survey done by the WHO indicates that a majority of the world population tends to use plants for treating diseases. Cancer, the second largest cause of death after cardiovascular disease accounts for about 3500 million people globally. Due to the serious side effects of synthetic chemopreventive agents, research is going onto investigate the nature derived chemopreventive agents. In addition to the plant-derived compounds, marine, and animal resources also play an important role as clinically beneficial anticancer agents with minimal or no toxicity. The best examples for plant-derived compounds include vincristine, vinblastine, irinotecan, etoposide, and paclitaxel; they have a different mode of action against cancer such as interaction with microtubules, inhibition of topoisomerases I or II, alkylation of DNA, and interference with tumor signal transduction. The natural products from marine sources such as bryostatin, squalamine exhibit a significant antimitotic, and anti-angiogenic activities. The benefits of various anticancer drugs derived from natural products are the fact that it can have its effect on cancer cells alone without harming healthy cells, which is unlikely to be the case with other conventional chemotherapeutics. In this review, various natural products and their anticancer properties have been discussed briefly.
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- 2019
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18. Predicting potentially permissive substitutions that improve the fitness of A(H1N1)pdm09 viruses bearing the H275Y NA substitution
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Aeron C. Hurt, Patrick C. Reading, Rubaiyea Farrukee, Gunalan, and Sebastian Maurer-Stroh
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Genetics ,chemistry.chemical_classification ,Mutation ,biology ,Phylogenetic tree ,Sequence analysis ,viruses ,In silico ,medicine.disease_cause ,Virus ,Enzyme ,chemistry ,biology.protein ,medicine ,Permissive ,Neuraminidase - Abstract
Oseltamivir-resistant influenza viruses arise due to amino-acid mutations in key residues, but these changes often reduce their replicative and transmission fitness. Widespread oseltamivir-resistance has not yet been observed in A(H1N1)pdm09 viruses. However, it is known that permissive mutations in the neuraminidase (NA) of former seasonal A(H1N1) viruses from 2007-2009 buffered the detrimental effect of the NA H275Y mutation, resulting in fit oseltamivir-resistant viruses that circulated widely. This study explored two approaches to predict permissive mutations that may enable a fit H275Y A(H1N1)pdm09 variant to arise.A computational approach used phylogenetic andin silicoprotein stability analyses to predict potentially permissive mutations, which were then evaluated byin vitroNA enzyme activity and expression analysis, followed byin vitroreplication. The second approach involved the generation of a virus library which encompassed all possible individual 2.9 × 104codon mutations in the NA whilst keeping H275Y fixed. To select for variant viruses with the greatest fitness, the virus library was serially passaged in ferrets (via contact and aerosol transmission) and resultant viruses were deep sequenced.The computational approach predicted three NA permissive mutations, and even though they only offset thein vitroimpact of H275Y on NA enzyme expression by 10%, they could restore replication fitness of the H275Y variant in A549 cells. In our experimental approach, a diverse virus library (97% of 8911 possible single amino-acid substitutions were sampled) was successfully transmitted through ferrets, and sequence analysis of resulting virus pools in nasal washes identified three mutations that improved virus transmissibility. Of these, one NA mutation, I188T, has been increasing in frequency since 2017 and is now present in 90% of all circulating A(H1N1)pdm09 viruses.Overall, this study provides valuable insights into the evolution of the influenza NA protein and identified several mutations that may potentially facilitate the emergence of a fit H275Y A(H1N1)pdm09 variant.
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- 2021
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19. Importance of Homology Modeling for Predicting the Structures of GPCRs
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Seshan Gunalan, Kanagasabai Somarathinam, Diwakar Kumar, Ananthasri Sailapathi, and Gugan Kothandan
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0301 basic medicine ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Chemistry ,InformationSystems_INFORMATIONSTORAGEANDRETRIEVAL ,Computational biology ,Homology modeling ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) ,030217 neurology & neurosurgery ,G protein-coupled receptor - Abstract
Homology modeling is one of the key discoveries that led to a rapid paradigm shift in the field of computational biology. Homology modeling obtains the three dimensional structure of a target protein based on the similarity between template and target sequences and this technique proves to be efficient when it comes to studying membrane proteins that are hard to crystallize like GPCR as it provides a higher degree of understanding of receptor-ligand interaction. We get profound insights on structurally unsolved, yet clinically important drug targeting proteins through single or multiple template modeling. The advantages of homology modeling studies are often used to overcome various problems in crystallizing GPCR proteins that are involved in major disease-related pathways, thus paving way to more structural insights via in silico models when there is a lack of experimentally solved structures. Owing to their pharmaceutical significance, structural analysis of various GPCR proteins using techniques like homology modeling is of utmost importance.
- Published
- 2021
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20. Experimental study of roll-formed aluminium lipped channel beams in shear
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Shanmuganathan Gunalan, Hassan Karampour, Keerthan Poologanathan, and Milad Rouholamin
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Materials science ,Fabrication ,business.industry ,Mechanical Engineering ,H300 ,chemistry.chemical_element ,020101 civil engineering ,02 engineering and technology ,Building and Construction ,Structural engineering ,Durability ,0201 civil engineering ,Corrosion ,Shear (sheet metal) ,020303 mechanical engineering & transports ,0203 mechanical engineering ,chemistry ,Aluminium ,Low elastic modulus ,business ,Beam (structure) ,Civil and Structural Engineering ,Communication channel - Abstract
Use of aluminium sections as primary load bearing members has recently expanded considerably in the building industry. Aluminium as a new constructional material has several advantages in building structures including corrosion resistance, durability, high strength-to-weight ratio, reduced cost of transportation and ease of erection and fabrication. The popularity of aluminium structures has attracted attention regarding the efficiency and design of many sections, and roll-formed lipped channel beam (LCB) is one of these commonly used sections. However, aluminium LCBs are prone to shear buckling failures due to its increased web slenderness and low elastic modulus compared to steel. Hence an experimental study was conducted to investigate the shear behaviour of LCBs and to verify the current design rules to accurately predict the shear strengths. Shear tests have been conducted using ten different generally available roll-formed aluminium LCBs. The test sections were loaded at mid-span at the shear centre until failure. The results obtained from the tests were then compared with the predictions using the current shear design rules in the Australian/New Zealand standards and Eurocodes for both aluminium structures and cold-formed steel structures as their shear behaviour are quite similar. This paper presents the details and results of this experimental study and comparison with shear design rules based on current design rules.
- Published
- 2020
21. Utilising animal models to evaluate oseltamivir efficacy against influenza A and B viruses with reduced in vitro susceptibility
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Danielle E. Anderson, Martin L. Hibberd, Sebastian Maurer-Stroh, Rubaiyea Farrukee, Ding Yuan Oh, Aeron C. Hurt, Celeste Ming-Kay Tai, Veronika von Messling, Ian G. Barr, Gary Yuk-Fai Lau, and Vithiagaran Gunalan
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Male ,RNA viruses ,Viral Diseases ,viruses ,Drug Evaluation, Preclinical ,Monkeys ,medicine.disease_cause ,chemistry.chemical_compound ,Macaque ,H1N1 ,Ferrets ,Influenza ,Viral release ,Influenza viruses ,Influenza A virus ,Influenza B virus ,Grippe ,Influenza A Virus, H1N1 Subtype ,Biology (General) ,Pathology and laboratory medicine ,Mammals ,0303 health sciences ,030302 biochemistry & molecular biology ,Eukaryota ,virus diseases ,Medical microbiology ,Infectious Diseases ,Vertebrates ,Viruses ,Female ,Macrolides ,Pathogens ,medicine.drug ,Research Article ,Primates ,Oseltamivir ,Viral Release ,medicine.drug_class ,QH301-705.5 ,Immunology ,Mutation, Missense ,Neuraminidase ,Biology ,Microbiology ,Virus ,03 medical and health sciences ,Zanamivir ,Orthomyxoviridae Infections ,Virology ,Old World monkeys ,Genetics ,medicine ,Animals ,Viral shedding ,Molecular Biology ,030304 developmental biology ,Medicine and health sciences ,Influenza A Virus, H3N2 Subtype ,fungi ,Organisms ,Viral pathogens ,Biology and Life Sciences ,RC581-607 ,Microbial pathogens ,Disease Models, Animal ,Macaca fascicularis ,chemistry ,Amino Acid Substitution ,Amniotes ,biology.protein ,Parasitology ,Peramivir ,Antiviral drug ,Immunologic diseases. Allergy ,Viral Transmission and Infection ,Orthomyxoviruses - Abstract
The neuraminidase (NA) inhibitor (NAI) oseltamivir (OST) is the most widely used influenza antiviral drug. Several NA amino acid substitutions are reported to reduce viral susceptibility to OST in in vitro assays. However, whether there is a correlation between the level of reduction in susceptibility in vitro and the efficacy of OST against these viruses in vivo is not well understood. In this study, a ferret model was utilised to evaluate OST efficacy against circulating influenza A and B viruses with a range of in vitro generated 50% inhibitory concentrations (IC50) values for OST. OST efficacy against an A(H1N1)pdm09 and an A(H1N1)pdm09 virus with the H275Y substitution in neuraminidase was also tested in the macaque model. The results from this study showed that OST had a significant impact on virological parameters compared to placebo treatment of ferrets infected with wild-type influenza A viruses with normal IC50 values (~1 nM). However, this efficacy was lower against wild-type influenza B and other viruses with higher IC50 values. Differing pathogenicity of the viruses made evaluation of clinical parameters difficult, although some effect of OST in reducing clinical signs was observed with influenza A(H1N1) and A(H1N1)pdm09 (H275Y) viruses. Viral titres in macaques were too low to draw conclusive results. Analysis of the ferret data revealed a correlation between IC50 and OST efficacy in reducing viral shedding but highlighted that the current WHO guidelines/criteria for defining normal, reduced or highly reduced inhibition in influenza B viruses based on in vitro data are not well aligned with the low in vivo OST efficacy observed for both wild-type influenza B viruses and those with reduced OST susceptibility., Author summary Oseltamivir (Tamiflu) is an antiviral widely used for the treatment of infection due to influenza viruses and is especially useful for the treatment of severely ill high-risk patients. Antiviral resistance to oseltamivir is of concern as it can undermine the utility of the drug. Influenza viruses can become less susceptible to oseltamivir due to amino acid substitutions that arise in the viral surface protein, neuraminidase (NA). During influenza surveillance, to monitor for resistance, laboratory experiments are carried out to measure viral susceptibility to oseltamivir, whereby the quantity of drug needed to inhibit NA enzyme action is measured. However, how well these laboratory measurements predict resistance of viruses to oseltamivir in a clinical setting is not well understood. In this study, we developed an animal model to evaluate this relationship between laboratory data and clinical efficacy in more detail and demonstrated that in vivo efficacy of oseltamivir is lower against viruses that show reduced inhibition by oseltamivir in laboratory testing. A key finding from our analysis was that oseltamivir had reduced efficacy in reducing viral shedding against wild-type influenza B viruses compared to wild-type influenza A viruses, which has implications on how data from influenza B viruses with reduced susceptibility are currently being interpreted.
- Published
- 2020
22. Fastened Aluminum-Lipped Channel Sections Subjected to Web Crippling under Two-Flange Loading Conditions: Experimental Study
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Shanmuganathan Gunalan, Husam Alsanat, Hong Guan, Keerthan Poologanathan, and Charalampos Baniotopoulos
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Materials science ,business.industry ,Mechanical Engineering ,Structural system ,chemistry.chemical_element ,020101 civil engineering ,02 engineering and technology ,Building and Construction ,Structural engineering ,Flange ,0201 civil engineering ,020303 mechanical engineering & transports ,0203 mechanical engineering ,chemistry ,Buckling ,Mechanics of Materials ,Aluminium ,General Materials Science ,business ,Civil and Structural Engineering ,Communication channel - Abstract
Thin-walled members in structural systems are highly vulnerable to buckling instabilities, including web crippling. Aluminum alloy members are more prone to this kind of failure due to thei...
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- 2020
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23. Unveiling the Accuracy of Homology Modeling to Elucidate the Structure of GPCRs-HIV Co-receptor-CCR5 as a Case Study
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Gunalan Seshan, Vadivelu Aanand, Somarathinam Kanagasabai, Gugan Kothandan, Changdev G. Gadhe, and Rajendran Anitha
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Co-receptor ,Chemistry ,Drug Discovery ,Human immunodeficiency virus (HIV) ,medicine ,Pharmaceutical Science ,Molecular Medicine ,Computational biology ,Homology modeling ,Bioinformatics ,medicine.disease_cause ,G protein-coupled receptor - Published
- 2018
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24. Numerical study on bearing behaviour and design of aluminium sub-heads in façade systems
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Nima Talebian, Benoit P. Gilbert, Hong Guan, Masoumeh Akbari, and Shanmuganathan Gunalan
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Bearing (mechanical) ,Materials science ,business.industry ,Mechanical Engineering ,chemistry.chemical_element ,Building and Construction ,Structural engineering ,Flange ,Wind engineering ,Finite element method ,Steel design ,law.invention ,chemistry ,Aluminium ,law ,business ,Failure mode and effects analysis ,Civil and Structural Engineering ,Parametric statistics - Abstract
A sub-head refers to the horizontal member at the top of an aluminium window wall system. Under wind load, bearing failure of the aluminium sub-head (ASH) flange due to its long length is a common failure mode, being subjected to high concentrated load transferred from the vertical members (mullions). The bearing behaviour of ASH sections was previously investigated experimentally by the authors and suitable equations (DRA I ) were proposed to predict the bearing capacities. These design rules were manufacturer and product specific and only applicable for sections considered in the test plan. To address these limitations, the present study further investigates the behaviour and design of ASH sections through non-linear static analyses using ABAQUS, based on implicit integration schemes. The effects of mesh size, element type, and loading plates on the bearing behaviour of ASH section under different loading and boundary conditions was addressed. The finite element models were validated against the test results in terms of ultimate loads, load–displacement curves and failure modes, and the validated model was then used to perform an extensive parametric study. A broad range of ASH sections covering flange widths ranging from 40 to 100 mm, thicknesses varying between 2 and 4 mm, bearing widths ranging from 50 to 150 mm, and six engagement lengths (5 to 30 mm) was considered in the parametric study. It should be noted that the ultimate loads obtained from the parametric study are not product nor manufacturer specific. Since no aluminium design rules exist to predict the bearing capacities of ASH sections, the accuracy of the current cold-formed steel design rules (DRSs) and that of DRA I were assessed. Both DRSs and DRA I were found not to be suitable for ASH sections in window walls, hence appropriate modifications were made in this study and the proposed design rules (DRA P ) predicted accurate bearing capacities which agreed well with the numerical results.
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- 2021
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25. Web crippling investigations of aluminium lipped channel sections under one-flange loading conditions
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Hong Guan, Shanmuganathan Gunalan, Husam Alsanat, and Keerthan Poologanathan
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business.industry ,Mechanical Engineering ,Structural system ,chemistry.chemical_element ,020101 civil engineering ,02 engineering and technology ,Building and Construction ,Structural engineering ,Flange ,0201 civil engineering ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Flexural strength ,Buckling ,chemistry ,Aluminium ,visual_art ,Aluminium alloy ,visual_art.visual_art_medium ,business ,Civil and Structural Engineering ,Communication channel - Abstract
Roll-formed aluminium sections have recently been utilised in structural systems as load-bearing members. Commonly used as flexural members, these sections are vulnerable to various buckling instabilities including web crippling failure. The current web crippling design guidelines are imperial in nature and their suitability for newly developed sections may not be accurate and reliable. Therefore, this study aims to investigate the web crippling behaviour of and design considerations for unfastened roll-formed aluminium lipped channel (ALC) sections under one-flange loading conditions. An experimental investigation was conducted for this purpose based on the AISI S909 web crippling test guidelines. Numerical simulations were subsequently conducted to extend the range of geometrical dimensions and aluminium alloy grades. A detailed assessment of the design rules given in the American, Australian, and European specifications was carried out using the acquired experimental and numerical results. Most of these guidelines were found to yield unsafe and unreliable predictions of the ultimate web crippling capacities, and therefore suitable modifications and improvement were proposed. The modified design rules predictions showed a good agreement with both experimental and numerical results. Hence it is recommended to adopt these improved design guidelines in relevant aluminium standards.
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- 2021
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26. Shear strength reduction of aluminium lipped channel beams due to web openings
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Shanmuganathan Gunalan, Milad Rouholamin, Hassan Karampour, and Keerthan Poologanathan
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Materials science ,business.industry ,Mechanical Engineering ,chemistry.chemical_element ,Building and Construction ,Bending ,Structural engineering ,Aspect ratio (image) ,Finite element method ,Shear (sheet metal) ,chemistry ,Aluminium ,Shear strength ,business ,Reduction (mathematics) ,Beam (structure) ,Civil and Structural Engineering - Abstract
Aluminium members are recently being used as main structural elements in residential, commercial and industrial buildings. Aluminium Lipped Channel Beam (LCB) is one of the popular thin-walled sections used in different applications in construction. Web openings are incorporated in these sections to accommodate building services when they are used as beams. Even though the bending, shear and web crippling behaviours of these sections were investigated in the past, their structural behaviour with web openings have not been investigated. Hence, experimental and numerical studies were conducted in this research to investigate the shear behaviour of these aluminium LCBs with web openings. An aspect ratio of one was considered in this study. A total of 17 tests were conducted first to investigate the shear behaviour of aluminium LCBs with circular web openings using three-point loading arrangement. Finite element models were developed with appropriate loading and boundary conditions and validated using the experimental results. A detailed parametric study was then undertaken using the currently available roll-formed aluminium LCBs with different thicknesses, grades and web opening sizes. The ultimate shear capacities and the shear capacity reduction factors obtained from the tests and finite element analyses were compared with the currently available design rules. This paper presents the details and results of the experimental and numerical studies on the shear behaviour of aluminium LCBs with circular web openings and the comparison with current and recently proposed design rules.
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- 2021
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27. Biophysical Reconstruction of the Signal Conduction Underlying Short-Latency Cortical Evoked Potentials Generated by Subthalamic Deep Brain Stimulation
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Kabilar Gunalan and Cameron C. McIntyre
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Male ,Internal capsule ,Deep brain stimulation ,medicine.medical_treatment ,Deep Brain Stimulation ,Models, Neurological ,Signal ,050105 experimental psychology ,Article ,03 medical and health sciences ,0302 clinical medicine ,Subthalamic Nucleus ,Physiology (medical) ,Cortex (anatomy) ,medicine ,Reaction Time ,Humans ,0501 psychology and cognitive sciences ,Evoked potential ,Evoked Potentials ,Aged ,Cerebral Cortex ,Chemistry ,05 social sciences ,Parkinson Disease ,Sensory Systems ,Antidromic ,Electrophysiology ,Subthalamic nucleus ,medicine.anatomical_structure ,Neurology ,Subthalamus ,Neurology (clinical) ,Neuroscience ,030217 neurology & neurosurgery - Abstract
Objective Direct activation of the hyperdirect (HD) pathway has been linked to therapeutic benefit from subthalamic deep brain stimulation (DBS) for the treatment of Parkinson’s disease (PD). We sought to quantify the axonal conduction biophysics of corticofugal axons directly stimulated by subthalamic DBS and reconcile those findings with short-latency cortical evoked potential (EP) results. Methods We used a detailed computational model of human subthalamic DBS to quantify axonal activation and conduction. Signal propagation to cortex was evaluated for medium (5.7 µm), large (10.0 µm), and exceptionally large (15.0 µm) diameter corticofugal axons associated with either internal capsule (IC) fibers of passage or the HD pathway. We then compared the modeling results to human cortical EP measurements that have described an exceptionally fast component (EP0) occurring ~1 ms after the stimulus pulse, a fast component (EP1) at ~3 ms, and a slower component (EP2) at ~5 ms. Results Subthalamic stimulation of the HD pathway with large and medium diameter axons propagated action potentials to cortex with timings that coincide with the EP1 and EP2 signals, respectively. Only direct activation of exceptionally large diameter fibers in the IC generated signals that could approach the EP0 timing. However, the action potential biophysics do not generally support the existence of a cortical EP less than 1.5 ms after DBS onset. Conclusions The EP1 and EP2 signals can be biophysically linked to antidromic activation of the HD pathway. Significance Theoretical reconstruction of cortical EPs from subthalamic DBS demonstrate a convergence of anatomical, biophysical, and electrophysiological results.
- Published
- 2019
28. Development of an innovative composite mullion
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Benoit P. Gilbert, Shanmuganathan Gunalan, S. Jiao, Henri Bailleres, and Balachandren Baleshan
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Cladding (construction) ,Engineering ,Waterproofing ,Thermal isolation ,chemistry ,business.industry ,Aluminium ,Composite number ,chemistry.chemical_element ,Facade ,Structural engineering ,Mullion ,business - Abstract
The facade, as the exterior cladding of a building, is an essential component which provides waterproofing, thermal isolation, light transparency and structural independence against environment actions. The vertical member, named mullion, is the dominant wind load-bearing structural member in this facade system. Even though aluminium is a durable material, the conventional aluminium frame is weak in thermal performance. On the other hand, timber frames are preferred by architects due to their aesthetic appearance and sustainability. Therefore, an innovative composite mullion was developed in this study using aluminium and timber to achieve the best features of both materials. An experimental study was also conducted to verify the structural performance of the composite mullion. Four-point bending tests were performed to investigate the bending behaviour of the newly developed product. The test results showed that the section moment capacities of the composite mullions are greater than the traditional aluminium mullions. © 2019 Taylor & Francis Group, London, UK.
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- 2019
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29. Understanding the dual mechanism of bioactive peptides targeting the enzymes involved in Renin Angiotensin System (RAS): An in-silico approach
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Ravi Manoharan, Kanagasabai Somarathinam, S. M. Jaimohan, Shantkriti Srinivasan, Seshan Gunalan, Jayanti Bhattacharya, Sowmya Ramachandran, Gugan Kothandan, and Sekar Kanagaraj
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chemistry.chemical_classification ,Dual inhibition ,0303 health sciences ,biology ,In silico ,030303 biophysics ,Angiotensin-converting enzyme ,General Medicine ,Dual mechanism ,03 medical and health sciences ,Enzyme ,chemistry ,Biochemistry ,Structural Biology ,Docking (molecular) ,Renin–angiotensin system ,biology.protein ,Molecular Biology - Abstract
Understanding the dual inhibition mechanism of food derivative peptides targeting the enzymes (Renin and Angiotensin Converting enzyme) in the Renin Angiotensin System. Two peptides RALP and WYT were reported to possess antihypertensive activity targeting both renin and ACE, and we have used molecular docking and molecular dynamics simulation, in order to understand the underlying mechanism. The selected peptides (RALP and WYT) from the series of peptides reported were docked to renin and ACE and two binding modes were selected based on the binding energy, interaction pattern and clusters of docking simulation. The enzyme-peptide complexes for renin and ACE (Renin/RALP1,2; ACE/RALP1,2; Renin/WYT1,2 and ACE/WYT1,2) were subjected to molecular dynamics simulation. Our results identified that the peptides inhibiting renin, tends to move out of the binding pockets (S1’ S2’) which is critical for potent binding and occupies the less important pockets (S4 and S3). This could possibly be the reason for its low potency. Whereas, the same peptides targeting ACE, tends to be intact in the pocket because of the metal ion coordination and there is an ample room to improve on its efficacy. Our results further pave way for the biochemist, medicinal chemist to design dual peptides targeting the RAS effectively. Communicated by Ramaswamy H. Sarma
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- 2019
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30. Experimental investigation of an innovative composite mullion made of aluminium and timber
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Henri Baillères, Benoit P. Gilbert, S. Jiao, Balachandren Baleshan, and Shanmuganathan Gunalan
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Waterproofing ,business.industry ,Computer science ,Composite number ,0211 other engineering and technologies ,chemistry.chemical_element ,02 engineering and technology ,Building and Construction ,Structural engineering ,Cladding (construction) ,chemistry ,Thermal isolation ,Mechanics of Materials ,Aluminium ,021105 building & construction ,Architecture ,Facade ,021108 energy ,Curtain wall ,Mullion ,Safety, Risk, Reliability and Quality ,business ,Civil and Structural Engineering - Abstract
The facade, as the exterior cladding of a building, is an essential element which provides waterproofing, thermal isolation and structural resistance against environmental actions. The vertical members in curtain wall facade systems, referred to as mullions, are the dominant load-bearing structural members. Despite aluminium being a durable material, conventional aluminium facade frames are weak in thermal performance, and hence thermal breaks are often used in the industry to provide the required insulation. In addition, timber frames may be preferred by building designers due to their aesthetic appearance and sustainability. Therefore, an innovative composite mullion was developed using aluminium and timber to combine the best features of both materials and is presented in this study. Experimental studies were also conducted to verify the structural performance of the composite mullion. The first series of tests was performed to investigate various aluminium-timber connections to ensure composite action. Four different connection types were considered in this study and the optimum connection was chosen and discussed. Four-point bending tests were performed next to investigate the bending behaviour and strength of the newly developed mullion as well as traditional aluminium mullions under positive and negative wind loading scenarios. It was found that the new composite mullions achieved higher section moment capacities than the traditional aluminium mullions, while being energy-efficient, aesthetically pleasing and more sustainable.
- Published
- 2021
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31. Web crippling of cold-formed carbon steel, stainless steel, and aluminium channels: Investigation and design
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Craig Higgins, Shanmuganathan Gunalan, Satheeskumar Navaratnam, Alex McIntosh, Perampalam Gatheeshgar, and Keerthan Poologanathan
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Materials science ,Carbon steel ,business.industry ,Metals and Alloys ,chemistry.chemical_element ,020101 civil engineering ,Strength factor ,02 engineering and technology ,Building and Construction ,Structural engineering ,Flange ,engineering.material ,Finite element method ,0201 civil engineering ,020303 mechanical engineering & transports ,0203 mechanical engineering ,chemistry ,Mechanics of Materials ,Aluminium ,engineering ,Fe model ,business ,Cold forming ,Civil and Structural Engineering ,Communication channel - Abstract
Cold-Formed (CF) structural members have recently drawn significant attention in light gauge steel construction. The employment of the different materials, for example CF carbon steel, stainless steel and aluminium, are becoming more common. These structural members are often subjected to concentrated loading conditions, which ultimately leads to failure through web crippling. A plethora of experimental and numerical studies have investigated the web crippling strength and behaviour of CF carbon steel lipped channel sections. However, only limited studies are available for CF stainless steel and aluminium members. This paper presents the investigation of the web crippling strength of CF lipped channel beams under End Two Flange (ETF) loadings and aims to propose a unified equation considering strength factor. Finite Element (FE) models of CF carbon steel, aluminium, and stainless steel lipped channel beams were developed and validated against the available web crippling ETF load case experimental data. Subsequently, a detailed parametric study was performed based on the validated FE models, to establish a wide-ranging data set. New ETF load case web crippling unified design guidelines were proposed for the CF lipped sections made of carbon steel, stainless steel, and aluminium.
- Published
- 2021
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32. Hemocompatibility of Sulfuric Acid-Treated Metallocene Polyethylene and its Application in Reducing the Quantity of Medical Plastic Waste
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Saravana Kumar Jaganathan, Arunpandian Balaji, M. Selvakumar, Gunalan Sivakumar, Mahitosh Mandal, Ahmad Athif Mohd Faudzi, Anandhan Srinivasan, Eko Supriyanto, Hemanth Mohandas, Suhaini Kadiman, and Palaniappan Kasi
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chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,General Chemical Engineering ,Materials Science (miscellaneous) ,Sulfuric acid ,02 engineering and technology ,Polyethylene ,Sulfonic acid ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Adsorption ,chemistry ,Chemical engineering ,Materials Chemistry ,Organic chemistry ,Wetting ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Metallocene ,Protein adsorption - Abstract
The hazards of dumping medical plastics have created a huge demand to reduce the quantity of plastic usage without compromising its quality. The metallocene synthesized polyethylene is one such advent, however, its clinical usage is limited by the problem of hemocompatibility. This study investigates the effect of sulfuric acid-induced changes in metallocene polyethylene. Fourier transform infrared spectroscopy analysis illustrated the addition of OH and sulfonic acid group, which subsequently increased the wettability. An improvement in micro as well as nanosurface roughness was observed. Ultimately, the treated surfaces depicted delayed clotting time, adsorption of specific plasma proteins, reduced hemolysis, and resistance against platelet adhesion.
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- 2016
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33. Experimental investigation on the bearing behaviour of aluminium sub-heads in façade systems
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Hong Guan, Benoit P. Gilbert, Shanmuganathan Gunalan, Masoumeh Akbari, and Balachandren Baleshan
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Materials science ,Bearing (mechanical) ,Bending (metalworking) ,business.industry ,Mechanical Engineering ,chemistry.chemical_element ,020101 civil engineering ,02 engineering and technology ,Building and Construction ,Structural engineering ,Flange ,0201 civil engineering ,Steel design ,law.invention ,020303 mechanical engineering & transports ,0203 mechanical engineering ,chemistry ,Aluminium ,law ,Facade ,Bearing capacity ,business ,Slipping ,Civil and Structural Engineering - Abstract
In the building sector, the application of aluminium alloys in load carrying structures as well as building envelopes has received attention over the past decades. Under wind loading, the vertical members of window walls known as mullions, carry the horizontal load transferred from the glass panels. This load is then transferred to the sub-heads at the top and the sub-sills at the bottom which are connected to the structure. The aluminium sub-head flange due to its long length is susceptible to bending (bearing failure) under this loading condition, a phenomenon that has hitherto not been adequately researched. Hence the performance of aluminium sub-head sections subjected to bearing failure was investigated through a series of 42 tests. This study mainly explores the impacts of parameters such as the bearing width, the loading and boundary conditions, as well as various geometric sections, on the bearing failure of aluminium sub-heads. The significant failure modes observed in the tests were yielding at web-flange junction and slipping of the bearing plate. Currently, no design rules are available to predict the bearing capacity of aluminium sub-heads. Hence a comparison of the ultimate bearing capacities of the test results and the design capacities obtained using the available cold-formed steel design specifications was performed. The code-predicted design strengths were found to be overly conservative for aluminium sub-head sections in window walls. Therefore, new design equations were developed to ensure safe, economic and reliable design of aluminium sub-heads using a wide range of bearing capacity data obtained from the experimental studies. The proposed design rules were found to be in precise agreement with the experimental values.
- Published
- 2020
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34. Crystal structure and hirshfeld surface analysis of 1, 2, 3, triazole bridged pyrrolizidine grafted macrocycle
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Perumal Rajakumar, S. Usharani, Gunalan Seshan, Perumal Prabhakaran, Kothandan Gugan, and Somarathinam Kanagasabai
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010405 organic chemistry ,Hydrogen bond ,Chemistry ,Intermolecular force ,General Chemistry ,Crystal structure ,010402 general chemistry ,Ring (chemistry) ,01 natural sciences ,0104 chemical sciences ,Crystallography ,Intramolecular force ,Molecule ,Single crystal ,Monoclinic crystal system - Abstract
The title compound was synthesized and characterized by 1H NMR and 13C NMR. The structure of the compound was confirmed through a single crystal X-ray diffraction study. The compound was crystallized in the monoclinic crystal system with the space group P 21/n. The pyrrolizidine moiety of ring A adopts an envelope conformation and ring B as twisted envelope conformation. The molecule exhibited both intermolecular and intramolecular hydrogen bonds. The intermolecular C—H•••N hydrogen bond is involved in the crystal structure stabilization. The molecule also observed C—H•••π, and π—π types of interactions crucial for stability. Hirshfeld surface analysis was carried out to investigate nature intermolecular contact in the crystal. Further, the 2D fingerprint has provided the information about the percentage contribution of intermolecular contact and reveals that the H•••H (62.3%) contact has a maximum contribution when compared to the other intermolecular contacts.
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- 2020
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35. Role of Microbial Competition on Activity of 2,4-D Degrading Alcaligenes xylosoxidans Strain Introduced into Fumigated Soil
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J.-C. Fournier and Gunalan M.-P. Charnay
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Strain (chemistry) ,Chemistry ,media_common.quotation_subject ,Alcaligenes xylosoxidans ,Competition (biology) ,media_common ,Microbiology - Published
- 2018
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36. Correlation between Levels of Serum Amylase, Lipase and Triglyceride in Acute Pancreatitis Patients
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Gunalan Govindarajan and Nina Tristina
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amylase ,medicine.medical_specialty ,lcsh:Medicine ,Inflammation ,Serum amylase ,chemistry.chemical_compound ,Internal medicine ,Hyperlipidemia ,lipase ,medicine ,triglyceride ,Amylase ,Lipase ,lcsh:R5-920 ,biology ,Triglyceride ,business.industry ,lcsh:R ,General Medicine ,medicine.disease ,Acute pancreatitis ,Endocrinology ,medicine.anatomical_structure ,chemistry ,biology.protein ,medicine.symptom ,lcsh:Medicine (General) ,Pancreas ,business - Abstract
Background : Acute pancreatitis is an inflammation of pancreas associated with reversible pancreatic parenchymal injury. Studies in several countries indicate that the levels of amylase and lipase are usually elevated among patients with acute pancreatitis. Furthermore, hyperlipidemia, mainly high levels of triglycerides, may present in acute pancreatitis. The aim of this study was to determine the levels of serum amylase and lipase as well as their correlation with serum triglyceride level in acute pancreatitis patients. Methods : A retrospective study was conducted on medical records of 48 acute pancreatitis patients in Dr. Hasan Sadikin General Hospital Bandung, Indonesia from 2007to 2011. Data collected from the medical records were age, sex, levels of serum amylase, lipase and triglyceride. The distribution of data was determined using Shapiro-Wilk test. The correlation between serum pancreatic enzyme and triglyceride was analyzed using Spearman-rank test. Results : Most patients had increased levels of serum amylase and lipase in this study. However, no correlation between serum amylase and triglyceride (p-value = 0.312) was found. Furthermore, there was no correlation between serum lipase and triglyceride (p-value = 0.241). Conclusions : The levels of serum amylase and lipase increase in most patients with acute pancreatitis with no significant correlation between serum pancreatic enzymes (amylase and lipase) and triglyceride. Keywords : Acute pancreatitis, amylase, lipase, triglyceride DOI : 10.15850/amj.v2n1.420
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- 2015
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37. Playing Hide and Seek: How Glycosylation of the Influenza Virus Hemagglutinin Can Modulate the Immune Response to Infection
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Yi Mo Deng, Emma R. Job, Michelle D. Tate, Vithiagaran Gunalan, Sebastian Maurer-Stroh, Patrick C. Reading, and School of Biological Sciences
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Glycosylation ,glycosylation ,Orthomyxoviridae ,lcsh:QR1-502 ,Virus Attachment ,Hemagglutinin (influenza) ,Hemagglutinin Glycoproteins, Influenza Virus ,Review ,Adaptive Immunity ,influenza virus ,lcsh:Microbiology ,Antigenic drift ,Microbiology ,chemistry.chemical_compound ,Immune system ,N-linked glycosylation ,Virology ,Humans ,immune evasion ,biology ,Acquired immune system ,biology.organism_classification ,Immunity, Innate ,Science::Biological sciences [DRNTU] ,carbohydrates (lipids) ,Infectious Diseases ,chemistry ,Host-Pathogen Interactions ,Humoral immunity ,biology.protein ,lectin - Abstract
Seasonal influenza A viruses (IAV) originate from pandemic IAV and have undergone changes in antigenic structure, including addition of glycans to the hemagglutinin (HA) glycoprotein. The viral HA is the major target recognized by neutralizing antibodies and glycans have been proposed to shield antigenic sites on HA, thereby promoting virus survival in the face of widespread vaccination and/or infection. However, addition of glycans can also interfere with the receptor binding properties of HA and this must be compensated for by additional mutations, creating a fitness barrier to accumulation of glycosylation sites. In addition, glycans on HA are also recognized by phylogenetically ancient lectins of the innate immune system and the benefit provided by evasion of humoral immunity is balanced by attenuation of infection. Therefore, a fine balance must exist regarding the optimal pattern of HA glycosylation to offset competing pressures associated with recognition by innate defenses, evasion of humoral immunity and maintenance of virus fitness. In this review, we examine HA glycosylation patterns of IAV associated with pandemic and seasonal influenza and discuss recent advancements in our understanding of interactions between IAV glycans and components of innate and adaptive immunity. Published version
- Published
- 2014
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38. Web crippling behaviour and design of aluminium lipped channel sections under two flange loading conditions
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Shanmuganathan Gunalan, Konstantinos Daniel Tsavdaridis, Hong Guan, Poologanathan Keerthan, and Husam Alsanat
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Computer science ,chemistry.chemical_element ,020101 civil engineering ,02 engineering and technology ,Flange ,0201 civil engineering ,law.invention ,Cross section (physics) ,0203 mechanical engineering ,Aluminium ,law ,Consistency (statistics) ,Aluminium alloy ,Civil and Structural Engineering ,Parametric statistics ,Bearing (mechanical) ,business.industry ,Mechanical Engineering ,Building and Construction ,Structural engineering ,020303 mechanical engineering & transports ,TA ,chemistry ,visual_art ,visual_art.visual_art_medium ,TJ ,business ,Communication channel - Abstract
Aluminium alloys have recently drawn significant attention in structural applications due to its outstanding mechanical characteristics. Thin-walled members fabricated by aluminium alloys can be more competitive in construction industries than the conventional cold-formed steel sections, particularly in areas with high humidity and severe environmental conditions. Nevertheless, they are more vulnerable to various types of instability due to their relatively low elastic modulus compared to steel. Applying high concentrated load transversely on thin-walled members can cause critical damage to the web of the cross section called web crippling. Although a large number of studies has been performed to investigate the web crippling mechanisms on different types of sections, the existing studies are primarily of the empirical nature and thus merits further investigations. To fill the research gap, this study was thus performed based on our previously conducted experimental work to further comprehend the web crippling phenomenon of the roll-formed aluminium lipped channel (ALC) sections under the loading conditions of end-two-flange (ETF) and interior-two-flange (ITF). This was done through numerical investigations followed by a parametric study which are reported herein in details. A wide range of roll-formed ALC sections covering web slenderness ratios ranged from 28 to 130, inside bent radii ranging between 2 mm and 8 mm, bearing lengths ranged from 50 mm to 150 mm, and three sheeting aluminium alloy grades (5052-H32, 5052-H36 and 5052-H38) were considered in the parametric study. The acquired web crippling database was then used to assess the consistency and accuracy of the current design rules used in practice. It was found that the web crippling capacity determined by the current international specifications are unsafe and unreliable, whereas the predictions of the recently proposed equations agree very well. Furthermore, a Direct Strength Method (DSM)-based capacity prediction approach was proposed and then validated against the web crippling database acquired here as well as the experimental and numerical data for cold-formed steel lipped channel sections used in the literature.
- Published
- 2019
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39. Microwave-Assisted Surface Modification of Metallocene Polyethylene for Improving Blood Compatibility
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Eko Supriyanto, Palaniappan Kasi, Saravana Kumar Jaganathan, Hemanth Mohandas, and Gunalan Sivakumar
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Materials science ,Article Subject ,Biocompatibility ,Surface Properties ,Scanning electron microscope ,lcsh:Medicine ,Biocompatible Materials ,General Biochemistry, Genetics and Molecular Biology ,Contact angle ,chemistry.chemical_compound ,Materials Testing ,Spectroscopy, Fourier Transform Infrared ,Organometallic Compounds ,Surface roughness ,medicine ,Humans ,Microwaves ,Blood Coagulation ,General Immunology and Microbiology ,medicine.diagnostic_test ,lcsh:R ,General Medicine ,Polyethylene ,Clotting time ,chemistry ,Surface modification ,Partial Thromboplastin Time ,Hydrophobic and Hydrophilic Interactions ,Research Article ,Biomedical engineering ,Partial thromboplastin time - Abstract
A wide number of polymers are being used for various medical applications. In this work, microwave-assisted surface modification of metallocene polyethylene (mPE) was studied. FTIR analysis showed no significant changes in the chemical groups after treatment. Contact angle analysis revealed a decrease in contact angle of the treated samples insinuating increasing hydrophilicity and better biocompatibility. Qualitative analysis of treated samples using scanning electron microscope (SEM) depicted increasing surface roughness and holes formation further corroborating the results. Coagulation assays performed for estimating prothrombin time (PT) and activated partial thromboplastin time (APTT) showed an increase in the clotting time which further confirmed the improved blood compatibility of the microwave-treated surfaces. Further, the extent of hemolysis in the treated sample was lower than the untreated one. Hence, microwave-assisted surface modification of mPE resulted in enhanced blood compatibility. Improved blood compatibility of mPE may be exploited for fabrication of artificial vascular prostheses, implants, and various blood contacting devices.
- Published
- 2013
- Full Text
- View/download PDF
40. Aloe barbadensis Miller mediated green synthesis of mono-disperse copper oxide nanoparticles: Optical properties
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Rajendran Venckatesh, Rajeshwari Sivaraj, and Sangeetha Gunalan
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Green chemistry ,Copper oxide ,Luminescence ,Optical Phenomena ,Copper oxide nanoparticles ,Dispersity ,Nanoparticle ,Nanotechnology ,Aloe vera ,Analytical Chemistry ,chemistry.chemical_compound ,X-Ray Diffraction ,Spectroscopy, Fourier Transform Infrared ,Aloe ,Instrumentation ,Spectroscopy ,biology ,Plant Extracts ,Chemistry ,Health related ,Green Chemistry Technology ,biology.organism_classification ,Atomic and Molecular Physics, and Optics ,Cuo nanoparticles ,Chemical engineering ,Nanoparticles ,Spectrophotometry, Ultraviolet ,Copper - Abstract
In this paper, we report on the synthesis of nanostructured copper oxide particles by both chemical and biological method. A facile and efficient synthesis of copper oxide nanoparticles was carried out with controlled surface properties via green chemistry approach. The CuO nanoparticles synthesized are monodisperse and versatile and were characterized with the help of UV-Vis, PL, FT-IR, XRD, SEM, and TEM techniques. The particles are crystalline in nature and average sizes were between 15 and 30 nm. The morphology of the nanoparticles can be controlled by tuning the amount of Aloe vera extract. This new eco-friendly approach of synthesis is a novel, cheap, and convenient technique suitable for large scale commercial production and health related applications of CuO nanoparticles.
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- 2012
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- View/download PDF
41. HPTLC fingerprint profile of Bauhinia variegata Linn. leaves
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Gayathri Gunalan, K. Vijayalakshmi, and A. Saraswathy
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Microbiology (medical) ,Solvent system ,Ethanol ,Chromatography ,lcsh:Arctic medicine. Tropical medicine ,Traditional medicine ,Hptlc fingerprint ,Spots ,biology ,Formic acid ,Bauhinia variegata ,lcsh:RC955-962 ,lcsh:R ,Ethyl acetate ,lcsh:Medicine ,biology.organism_classification ,HPTLC ,chemistry.chemical_compound ,Acetic acid ,Infectious Diseases ,fingerprinting ,chemistry ,medicinal plants - Abstract
Objective To develop the finger print of medicinally and economically important leaves of Bauhinia variegata Linn. Methods Ethanol extract of the leaves were developed in the mobile phase of n-Hexane: Ethyl acetate: Formic acid: Acetic acid (70:30:1.0:1.0) using standard procedures and scanned under UV at 254 nm, 366nm and under visible light. Results The HPTLC fingerprinting of the ethanol extract has shown several peaks with different Rf values. 2.5 μL of ethanol extract showed 11 spots while 5 μL and 10 μL has shown 13 spots. 15μ L concentration gave 14 spots in the above said solvent system. Conclusions This finger print would be helpful in the identification and authentication of this species.
- Published
- 2012
42. Green synthesis of zinc oxide nanoparticles by aloe barbadensis miller leaf extract: Structure and optical properties
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Sivaraj Rajeshwari, Rajendran Venckatesh, and Gunalan Sangeetha
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Materials science ,Photoluminescence ,Mechanical Engineering ,Nanoparticle ,chemistry.chemical_element ,Mineralogy ,Zinc ,Aloe vera leaf extract ,Condensed Matter Physics ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,Zinc nitrate ,General Materials Science ,Particle size ,Fourier transform infrared spectroscopy ,Tem analysis ,Nuclear chemistry - Abstract
Biological methods for nanoparticle synthesis using microorganisms, enzymes, and plants or plant extracts have been suggested as possible ecofriendly alternatives to chemical and physical methods. In this paper, we report on the synthesis of nanostructured zinc oxide particles by both chemical and biological method. Highly stable and spherical zinc oxide nanoparticles are produced by using zinc nitrate and Aloe vera leaf extract. Greater than 95% conversion to nanoparticles has been achieved with aloe leaf broth concentration greater than 25%. Structural, morphological and optical properties of the synthesized nanoparticles have been characterized by using UV–Vis spectrophotometer, FTIR, Photoluminescence, SEM, TEM and XRD analysis. SEM and TEM analysis shows that the zinc oxide nanoparticles prepared were poly dispersed and the average size ranged from 25 to 40 nm. The particles obtained have been found to be predominantly spherical and the particle size could be controlled by varying the concentrations of leaf broth solution.
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- 2011
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43. AllerCatPro – Prediction of protein allergenicity potential from the protein sequence
- Author
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Vithiagaran Gunalan, G.F. Gerberick, Matthew Nguyen, Sebastian Maurer-Stroh, Vachiranee Limviphuvadh, Nora L Krutz, and Petra S. Kern
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Protein sequencing ,Chemistry ,General Medicine ,Computational biology ,Toxicology - Published
- 2018
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44. PHYSICOCHEMICAL CHARACTERISTICS AND SENSORY ATTRIBUTES OF WHEAT-BASED 'PAPADS' INCORPORATED WITH GREEN LEAFY VEGETABLES
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Sheetal Gupta, Jamuna Prakash, A. Jyothi Lakshmi, and Gunalan Vasanthi Kaveri
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Chemistry ,Wheat flour ,Nutritional quality ,Food science ,Leafy vegetables ,Proximate ,Safety, Risk, Reliability and Quality ,Sensory analysis ,Legume ,Food Science - Abstract
Papads are cereal or legume-based preserved products which are consumed after deep fat frying. They were chosen for value addition with two types of green leafy vegetables (GLV). Wheat-based papads were prepared using refined wheat flour, cumin seeds, salt and GLV, that is, shepu (Peucedanum graveolens) and kilkeerae (Amaranthus tricolor) at different levels in fresh (15 and 20%) and dehydrated forms (5 and 10%). Greens were analyzed for their proximate principles, selected minerals and vitamins. In the fried papads, fat uptake and expansion volume were determined. The fried papads were subjected to sensory analysis by a panel of 100 members. Expansion volume of papads with fresh greens and 5% dehydrated greens were satisfactory, but differences existed between the greens. Fat uptake of kilkeerae papads was similar to that of control papads but shepu-incorporated papad showed slightly lower absorption. Papads with 15-20% fresh greens and 5% dehydrated greens scored above 6 on a scale of 10 indicating acceptability of papads incorporated with greens. Mineral, vitamin and fiber content of greens-incorporated papads increased remarkably. Acceptability of papads in terms of physicochemical characteristics, sensory attributes and nutritional quality suggests the suitability of papads incorporated with greens.
- Published
- 2004
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- View/download PDF
45. Enhanced Blood Compatibility of Metallocene Polyethylene Subjected to Hydrochloric Acid Treatment for Cardiovascular Implants
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Saravana Kumar Jaganathan, Selvakumar Murugesan, Theertha Sudheer, Gunalan Sivakumar, Eko Supriyanto, Hemanth Mohandas, Sruthi Avineri Veetil, and Palaniappan Kasi
- Subjects
Blood Platelets ,medicine.medical_specialty ,Article Subject ,lcsh:Medicine ,Hydrochloric acid ,Biocompatible Materials ,General Biochemistry, Genetics and Molecular Biology ,Contact angle ,chemistry.chemical_compound ,Platelet Adhesiveness ,Platelet adhesiveness ,medicine ,Organometallic Compounds ,Humans ,Platelet ,Blood Coagulation ,Prothrombin time ,General Immunology and Microbiology ,medicine.diagnostic_test ,lcsh:R ,General Medicine ,Prostheses and Implants ,Polyethylene ,medicine.disease ,Hemolysis ,Surgery ,chemistry ,Cardiovascular Diseases ,Partial Thromboplastin Time ,Hydrochloric Acid ,Biomedical engineering ,Partial thromboplastin time ,Research Article - Abstract
Blood compatibility of metallocene polyethylene (mPE) was investigated after modifying the surface using hydrochloric acid. Contact angle of the mPE exposed to HCl poses a decrease in its value which indicates increasing wettability and better blood compatibility. Surface of mPE analyzed by using FTIR revealed no significant changes in its functional groups after treatment. Furthermore, scanning electron microscope images supported the increasing wettability through the modifications like pit formations and etching on the acid rendered surface. To evaluate the effect of acid treatment on the coagulation cascade, prothrombin time (PT) and activated partial thromboplastin time (APTT) were measured. Both PT and APTT were delayed significantly (P<0.05) after 60 min exposure implying improved blood compatibility of the surfaces. Hemolysis assay of the treated surface showed a remarkable decrease in the percentage of lysis of red blood cells when compared with untreated surface. Moreover, platelet adhesion assay demonstrated that HCl exposed surfaces deter the attachment of platelets and thereby reduce the chances of activation of blood coagulation cascade. These results confirmed the enhanced blood compatibility of mPE after HCl exposure which can be utilized for cardiovascular implants like artificial vascular prostheses, implants, and various blood contacting devices.
- Published
- 2014
- Full Text
- View/download PDF
46. Triggers of key calcium signals during erythrocyte invasion by Plasmodium falciparum
- Author
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Karthigayan Gunalan, Peter R. Preiser, Sally Shu Lin Yap, Xiaohong Gao, and School of Biological Sciences
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Cell biology ,Erythrocytes ,medicine.drug_class ,Plasmodium falciparum ,Cell ,General Physics and Astronomy ,chemistry.chemical_element ,Calcium ,Monoclonal antibody ,Microbiology ,Article ,General Biochemistry, Genetics and Molecular Biology ,Host-Parasite Interactions ,Organelle ,medicine ,Humans ,Malaria, Falciparum ,Receptor ,Calcium signaling ,Multidisciplinary ,biology ,Merozoites ,General Chemistry ,biology.organism_classification ,Biological sciences ,medicine.anatomical_structure ,chemistry ,Signal transduction ,Signal Transduction - Abstract
Invasion of erythrocytes by Plasmodium falciparum merozoites is a complex multi-step process mediated by specific interactions between host receptors and parasite ligands. Reticulocyte-binding protein homologues (RHs) and erythrocyte-binding-like (EBL) proteins are discharged from specialized organelles and used in early steps of invasion. Here we show that monoclonal antibodies against PfRH1 (an RH) block merozoite invasion by specifically inhibiting calcium signalling in the parasite, whereas invasion-inhibiting monoclonal antibodies targeting EBA175 (an EBL protein) have no effect on signalling. We further show that inhibition of this calcium signalling prevents EBA175 discharge and thereby formation of the junction between parasite and host cell. Our results indicate that PfRH1 has an initial sensing as well as signal transduction role that leads to the subsequent release of EBA175. They also provide new insights on how RH–host cell interactions lead to essential downstream signalling events in the parasite, suggesting new targets for malaria intervention., Plasmodium falciparum reticulocyte-binding protein homologue 1 (PfRH1) and erythrocyte-binding-like protein EBA175 are important for parasite invasion of host cells. Here, Gao et al. show that PfRH1 activates calcium signalling, which induces release of EBA175 and allows junction formation between host cell and parasite.
- Published
- 2013
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47. Contributions of Subsurface Cortical Modulations to Discrimination of Executed and Imagined Grasp Forces through Stereoelectroencephalography
- Author
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Jonathan P. Miller, Kabilar Gunalan, Brian A Murphy, and A Bolu Ajiboye
- Subjects
Male ,Central Nervous System ,0301 basic medicine ,lcsh:Medicine ,Electrode Recording ,Hands ,Electroencephalography ,Nervous System ,Diagnostic Radiology ,0302 clinical medicine ,Animal Cells ,Functional Magnetic Resonance Imaging ,Electrochemistry ,Medicine and Health Sciences ,Pinch Strength ,lcsh:Science ,Membrane Electrophysiology ,Musculoskeletal System ,Neurons ,Brain Mapping ,Multidisciplinary ,medicine.diagnostic_test ,Radiology and Imaging ,Motor Cortex ,Brain ,Anatomy ,Middle Aged ,16. Peace & justice ,Magnetic Resonance Imaging ,Central sulcus ,Chemistry ,Arms ,Bioassays and Physiological Analysis ,medicine.anatomical_structure ,Physical Sciences ,Female ,Cellular Types ,Primary motor cortex ,psychological phenomena and processes ,Geology ,Research Article ,Motor cortex ,Adult ,Imaging Techniques ,Neuroimaging ,Research and Analysis Methods ,Insular cortex ,Stereoelectroencephalography ,Fingers ,03 medical and health sciences ,Diagnostic Medicine ,medicine ,Humans ,Sensory cortex ,Electrode Potentials ,Electrophysiological Techniques ,Limbs (Anatomy) ,lcsh:R ,Biology and Life Sciences ,Cell Biology ,030104 developmental biology ,lcsh:Q ,Functional magnetic resonance imaging ,Neuroscience ,030217 neurology & neurosurgery - Abstract
Stereoelectroencephalographic (SEEG) depth electrodes have the potential to record neural activity from deep brain structures not easily reached with other intracranial recording technologies. SEEG electrodes were placed through deep cortical structures including central sulcus and insular cortex. In order to observe changes in frequency band modulation, participants performed force matching trials at three distinct force levels using two different grasp configurations: a power grasp and a lateral pinch. Signals from these deeper structures were found to contain information useful for distinguishing force from rest trials as well as different force levels in some participants. High frequency components along with alpha and beta bands recorded from electrodes located near the primary motor cortex wall of central sulcus and electrodes passing through sensory cortex were found to be the most useful for classification of force versus rest although one participant did have significant modulation in the insular cortex. This study electrophysiologically corroborates with previous imaging studies that show force-related modulation occurs inside of central sulcus and insular cortex. The results of this work suggest that depth electrodes could be useful tools for investigating the functions of deeper brain structures as well as showing that central sulcus and insular cortex may contain neural signals that could be used for control of a grasp force BMI.
- Published
- 2016
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- View/download PDF
48. Preparation and Characterization of Activated Carbons from Parthenium biomass by Physical and Chemical Activation Techniques
- Author
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Venckatesh Rajendran, G. Sangeetha Gunalan, and Rajeshwari Sivaraj
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Waste management ,biology ,Chemistry ,Biomass ,chemistry.chemical_element ,General Chemistry ,biology.organism_classification ,lcsh:Chemistry ,Parthenium ,Adsorption ,lcsh:QD1-999 ,Chemical engineering ,medicine ,Pyrolytic carbon ,Weed ,Pyrolysis ,Carbon ,Activated carbon ,medicine.drug - Abstract
Parthenium hysterphorous(Linn), a perennial weed of no known beneficial use was introduced as a containment of food grains imported from US with P1480 scheme. The colonization efficiency of the weed was much higher than other indigenous weeds resulting in the reduction of cultivable areas of agricultural lands. Therefore, attention was focused to find out the potential use of its biomass. In the present study the preparation and characterization of activated carbons by physical and chemical activation methods are reported and aims to prepare relatively well developed porous activated carbons as well as study various conditions and parameters that were involved during the process. Among the carbons prepared Zncl2impregnated carbon at the ratio of 1 was found to possess the characteristic features of an efficient adsorbent. Experimental results showed that pyrolytic and activation conditions leading to various final average temperatures had significant effect on the properties of activated carbons prepared.
- Published
- 2010
- Full Text
- View/download PDF
49. Contributions of Subsurface Cortical Modulations to Discrimination of Executed and Imagined Grasp Forces through Stereoelectroencephalography.
- Author
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Murphy, Brian A., Miller, Jonathan P., Gunalan, Kabilar, and Ajiboye, A. Bolu
- Subjects
ELECTROENCEPHALOGRAPHY ,ACQUISITIVENESS ,DIFFERENTIATION (Cognition) ,ELECTRODES ,INFORMATION processing - Abstract
Stereoelectroencephalographic (SEEG) depth electrodes have the potential to record neural activity from deep brain structures not easily reached with other intracranial recording technologies. SEEG electrodes were placed through deep cortical structures including central sulcus and insular cortex. In order to observe changes in frequency band modulation, participants performed force matching trials at three distinct force levels using two different grasp configurations: a power grasp and a lateral pinch. Signals from these deeper structures were found to contain information useful for distinguishing force from rest trials as well as different force levels in some participants. High frequency components along with alpha and beta bands recorded from electrodes located near the primary motor cortex wall of central sulcus and electrodes passing through sensory cortex were found to be the most useful for classification of force versus rest although one participant did have significant modulation in the insular cortex. This study electrophysiologically corroborates with previous imaging studies that show force-related modulation occurs inside of central sulcus and insular cortex. The results of this work suggest that depth electrodes could be useful tools for investigating the functions of deeper brain structures as well as showing that central sulcus and insular cortex may contain neural signals that could be used for control of a grasp force BMI. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
50. THE RELATIONSHIP BETWEEN CARBON, SULFUR, AND PYRITIC IRON IN THE AMJHORE DEPOSIT, BIHAR, INDIA
- Author
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A. Changkakoti, H. R. Krouse, H. S. Pandalai, and N. Gunalan
- Subjects
Sulfide ,Mineralogy ,chemistry.chemical_element ,Rohtas District ,engineering.material ,Ores ,Sediments ,chemistry.chemical_compound ,Geochemistry and Petrology ,Sulfate ,Isotope ,Sediment ,Geology ,Sedimentation ,Anoxic waters ,Sulfur ,Diagenesis ,Organic-Matter ,Geophysics ,chemistry ,engineering ,Shales ,Economic Geology ,Pyrite ,Oil shale - Abstract
Low C/S ratios have been generally observed in pyritiferous black shales of the lower Paleozoic and late Proterozoic (Berner and Raiswell, 1983). In addition to factors such as high rates of bacterial sulfate reduction which might have existed during these early periods due to the low oxygen content of ocean water, availability and quality of organic matter, or lack ofbioturbation and availability of reactive iron, low C/S ratios may also reflect low sedimentation rates. Three distinct situations within a single vertical stratigraphic column in the mid-Proterozoic Amjhore pyrite deposit reflect the effect of anoxic levels and sedimentation rates on pyrite formation. In the first (lower shale with a mean C/S ratio of 2.03), pyrite formation was diagenetic, whereas in the second (massive pyrite ore with a negligible carbon content) and the third (upper shale with a low C/S ratio of 0.27), pyrite formation took place under euxinic conditions. In environments where anoxic levels are high and the sedimentation rate low, low mean C/S ratios may occur. In such environments variations in total sulfate reduction per unit column of sediment deposited (resulting from variation in sedimentation rates or anoxic levels) are reflected in the slope of the carbon-sulfur plot by a greater slope. This may also result in lower intercepts on the sulfur axis. For upper shale samples the carbon-sulfur regression line has a very high slope of 3.73 and a low intercept on the sulfur axis of 0.21. Consistency of anoxic levels during deposition of upper shales is, however, indicated by the low standard deviation (0.051) of C/S data and a dominant control of the sedimentation rate on the sulfur content of the sediments is inferred. Sulfur isotope data on pyrite samples indicate an environment closed to SO (super -2) 4 which was initially open to H 2 S (or HS (super -) ) and later during deposition of upper shale became closed to it due to a limited supply of reactive iron. This confirms that the pyrite bed and upper shales were laid down in a restricted environment and substantiates the interpretation of the carbon-sulfur relationships observed in them.
- Published
- 1991
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