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Purpose The purpose of this paper is to present synthesis protocol of hydrogel composed of Chitosan (CS) and Poly(ethylene glycol) (PEG) and establish an understanding of its thermal responsive behavior. It aims to prove the basic temperature sensing ability of a novel CS-PEG-based hydrogel and define its sensing span. Design/methodology/approach This study includes synthesis of CS and PEG-based hydrogel samples by first performing dissolution of both constituents, respectively, and then adding Glutaraldehyde as the cross-linking agent. It further includes proposed hydrogel’s swelling studies and dynamic behavior testing, followed by hydrogel characterization by Fourier transform infrared spectroscopy, X-ray diffraction and SEM. The last section focuses on the use of proposed hydrogel as a temperature sensor. Findings Detailed experimental results show that a hydrogel comprising of CS and PEG presents a thermally responsive behavior. It offers potential to be used as a temperature responsive hydrogel-based sensor which could be used in medical applications. Originality/value This research study presents scope for future research in the field of thermally responsive bio-sensors. It provides basis for the fabrication of a thermal responsive sensor system based on hydrogels that can be used in specific medical applications.

Objectives: The objectives of the study were to evaluate the vascular and tissue response of Pakistani manufactured novel drug eluting stent (called N-DEAVOUR®) on a swine model and compare the results with XIENCE PRO™. Methodology: A total of 10 animals were used for the study and assigned randomly to each time-point group. The test articles were administered percutaneously and each animal was implanted with one stent in each one of the coronary arteries (3 in total) LCA (left circumflex artery), LAD (left anterior descending coronary artery), and RCA (right coronary artery). Additionally, a second test stent was implanted in some animals (4 in total). QCA (Quantitative Coronary Angiography) technique was used for measurements of the vessel at the target site. OCT (Optical Coherence Tomography) was performed only at follow up time-points which were 30, 90 and 180 days. Results: At 30 DFU, parameters for N-DEAVOUR® were comparable to those of both control (XIENCE PROTM and VISION) stents. At 90 days follow-up N-DEAVOUR® showed no statistically significant difference in performance for values of lumen area, stent area, area stenosis, and neointimal area against XIENCE PRO™. With reference to stent area, at 90 DFU, N-DEAVOUR® performed better than XIENCE PRO™ (p=0.0056). For neo-intimal area, area stenosis and lumen area, the differences between XIENCE PRO™ and N-DEAVOUR® were non-significant (p=0.13; p=0.9; p=0.086) respectively. These results indicate the positive potential of N-DEAVOUR® to be successfully implanted in clinical settings after necessary randomized clinical trials are executed. Conclusion: This study proved that the drug eluting stent examined in the present study is both safe and feasible. This study supports that this stent can move forward for human trials.

Drug eluting stents (DES) can efficiently reduce the atherosclerosis and restenosis issues of coronary artery as compared to bare metal stents due to the presence of pharmaceutically active agent on their surface. Nevertheless, the arising safety concerns of DES such as delayed healing and late in stent restenosis and thrombus, has stirred the research efforts to improve the outcomes of the DES. In this connection, attention is being shifted from the use of synthetic drug to natural drug for DES. In the present work, natural compound loaded polymeric films were synthesized and their antioxidant and anticoagulation capabilities were assessed through in vitro testing. The potential of the drug loaded polymeric films to curb the production of free radicals was evaluated by carrying out antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The in vitro platelet adhesion was investigated through static platelet adhesion test while effect of synthesized films on intrinsic coagulation pathway was investigated through activated partially thromboplastin time (APTT). Moreover, to further evaluate the blood compatibility of the developed drug loaded films, in vitro hemolytic and anti-thrombolytic assays were carried out. The obtained results indicated that, incorporating herbal compounds such as ginger, magnolol and curcumin, in polymeric matrix (PVA) has significantly improved the blood compatibility of the polymeric films. Hence, it can be concluded that the synthesized drug loaded polymeric films have the potential capability to be used as a potential coating material for coating biomedical implants with good anticoagulation and antioxidant property to cater the cardiovascular issues such as atherosclerosis, restenosis and thrombus formation.

Objectives: The aim of this pilot study was the first-in-man evaluation of the safety, feasibility, deliverability, and efficiency of the newly developed REJUVENATE® bare metal stent system in coronary artery disease. Methodology: Current study was a pilot non-randomized, multi-centric and prospective study which was intended to study the safety of the REJUVENATE® bare metal stent in Pakistani population over 10 months. Study endpoints included target vessel related myocardial infarction, stent thrombosis, in-stent restenosis, stroke and death. The diameter of the target lesions selected was between 3-4mm with length no more than 22mm. Only one BMS was implanted per patient. These patients had well defined regular clinical follow-ups and CT scan coronary angiography at the end of 10 months. Results: 20 patients suffering from coronary artery disease (CAD) including15 male subjects and 5 female subjects were enrolled in this study and were treated with REJUVENATE® BMS. 65% patients were hypertensive, 25% diabetics and 25% were active smokers. Out of the 20 stents implanted, 14 stents were implanted in the right coronary artery and 6 were implanted in the left circumflex artery. During this 10-month study period there was 10.65% of cases in which late lumen loss (lumen stenosis

Heart valve problems affect more than 100 million people worldwide. According to statistics, around 55% of valvular diseases are treated by a mechanical prosthesis. The first heart valve replaced model was the caged-ball valve, more than 50 models of heart valves designed by different companies. Each design has different aspects such as valve geometry, leaflets design, materials used for model manufacturing, coating techniques, and coating materials. Depending on the patient's need and condition, the native heart valve either replaced by a biological or mechanical heart valve. Biological valves are made of living tissues whereas mechanical valves manufactured by the biomaterials, which are biocompatible and do not causes any reaction inside the body. The prototype discussed in this paper provides good hemocompatibility, because of the biomaterial used in this prototype manufacturing. It will reduce tissue ingrowth, due to the enhanced leaflet ear of the orifice ring. Moreover, it will cause less thrombotic effects into the host due to greater contact angel of graphite and smooth surface of graphite after pyrolytic coating. The significant evolution of mechanical valve designs consists of valve geometry, coating technique, and materials. In this research, the 3D-CAD model of Bileaflet Mechanical Mitral Heart Valve was designed using SOLID WORKS 2016 and fabricated by 5-axis Computer Numeric Control (CNC) machine. Graphite was used for the fabrication of prototype and Pyrolytic Carbon (PyC) coating was performed with Chemical Vapor deposition (CVD) technique. Scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction (XRD) were used to determine the effects of CVD on surface topography and chemical structure of graphite model before and after coating. Furthermore, hemocompatibility of graphite and PyC analyzed through in-vitro hemolytic activity. The Characterization results showed that the Bileaflet Mechanical Mitral Heart valve prototype after PyC coating provides a smooth surface with improved hemocompatibility and less adhesion. Besides, the Mechanical Heart valves showed no hemolysis during the hemolytic activity. By virtue of its smooth and nonporous surface, it is antithrombotic and provides good hemodynamics. The advance long leaflet ear design reduces the tissue ingrowth around the orifice which will further limit the leaflets movement.

Wound treatment remains a challenge to many clinicians because of the complexities of the wound healing process. With the astonishing progress of biomedical engineering during the past few decades, conventional drug delivery systems have been evolved into smart drug delivery systems with stimuli-responsive characteristics. The objective of this study was to develop and evaluate an electromechanically actuated drug dispensation device which can release active pharmaceutical compound in a controlled fashion. Additive manufacturing was employed to design and fabricate the device. Haptic technology was used to provide stimulation for drug release, and Cicatrin was used to evaluate the drug release patterns of device. Drug release study was comprised of in vitro drug release, static study, and the purpose of this study was to develop a compliance chart for different wound conditions. The effectiveness of shortlisted drug regimen from compliance chart was validated through microbial study and animal studies. The results of animal studies were compared with commercially available drug release systems. The results of drug release studies gave different dose regimens for different wound conditions. The effective dose regimen was able to create 1-cm-wide microbial zone of inhibitions. The wound healing rate of mice for commercially available release system for five consecutive days was 10%, 10%, 20%, 40% and 50% and for test device was 10%, 30%, 60%, 90% and 100%. Hence, the device proved its effectiveness and efficacy of dosage regimen for wound healing applications through in vitro, microbial and in vivo studies. In conclusion, this device proved to be an accurate and specific drug delivery system with improved medication and therapeutic outcomes for personalized medication.

Objectives: The main objective of the study was to evaluate the implantation, safety, and vascular tissue effects of REJUVENATE® Cobalt Chromium Bare Metal Stent in the Porcine Coronary Restenosis model at short, mid and long-term follow up. Methodology: A total of 18 REJUVENATE® bare metal stents (CoCr, 95 µm strut thickness) were implanted into the coronary arteries (RCA, LCX and LAD) of the six pigs. Throughout the study period, stent patency, vascular response, percent stenosis, late lumen loss and performance of stent were evaluated by angiography, optical coherence tomography (OCT), and Histopathology (includes both Histopathology and histomorphometry) at 30, 90, and 180 days and compared with the results of control Bare Metal Stent Coflexus®. The mean, variance and standard deviation was analyzed using SPSS software. Results: OCT and QCA analysis demonstrated two cases of binary restenosis at 30 days follow-up and two at 90 days follow-up (33%). The mean area stenosed for Rejuvenate® was 34% as compared to 24% of Coflexus® and at 180 days follow up, it decreased to 21%. The histopathology analysis demonstrated favorable safety with acceptable levels of neointimal formation, with decreased levels of inflammation and complete endothelialization in 180 days. Conclusion: This study proved the potential safety of REJUVENATE® in porcine model and supports that this stent can move forward for the human trials.

For a connected graph $\mathcal {G}$ , the distance $d(u, v)$ between any two vertices $u$ , $v~\in ~\mathcal {V(G)}$ is defined as; $d(u,v)=\min _{\mathcal {P}_{u,v}}\{\text {length of}~\mathcal {P}_{uv}\}$ i.e the minimum length of path connecting any two vertices. Two vertices $u$ , $v$ of a graph $G$ are said to be resolved by a vertices $\mathcal {W}$ of a graph $\mathcal {G}$ if $d(u,w) \neq d(v,w)$ . An ordered set $\mathcal {W} = \{w_{1},w_{2},w_{3},\ldots,w_{k}\}\,\,\in \,\,V(G)$ is resolving set for a connected graph $G$ , if for any two vertices $u$ , $v$ there exists $w_{i} \in W$ such that $d(u,w_{i}) \neq d(v, w_{i})$ . The representation of vertices $v$ w.r.t $\mathcal {W}$ is represented by $r(v|\mathcal {W})$ which is $k$ -vector( $k$ -tuple) $(d(v,w_{1}),d(v,w_{2}),d(v,w_{3}),\ldots,d(v,w_{k}))$ . If the representation of all the vertices of graph $\mathcal {G}$ are different w.r.t $\mathcal {W}$ then $\mathcal {W}$ is the resolving set for $G$ [1]. A resolving set that contains minimum numbers of vertices is metric basis for $\mathcal {G}$ . The cardinality of smallest resolving set is the metric dimension of $\mathcal {G}$ , represented by $dim(\mathcal {G})$ [2], [3]. A family of connected graph $\mathcal {G}$ has unbounded metric dimension if $dim(\mathcal {G})$ depends on order of a graph. In this paper, we show that total graph of path power three and four have unbounded metric dimension. We also proved some results on edges of power of path graph.

We propose a new fractional-order (space and time) total variation regularized model for multiplicative noise removal in this research article. We use the regularly varying fuzzy membership degrees to characterize the likelihood of a pixel related to edges, texture regions, and flat regions to improve model efficiency. This approach is capable of maintaining edges, textures, and other image information while significantly reducing the blocky effect. We opt for the option of local actions. In order to efficiently find the minimizer of the prescribed energy function, the semi-implicit gradient descent approach is used (which derives the corresponding fractional-order Euler-Lagrange equations). The existence and uniqueness of a solution to the suggested variational model are proved. Experimental results show the efficiency of the suggested model in visual enhancement, preserving details and reducing the blocky effect while extracting noise as well as an increase in the PSNR (dB), SSIM, relative error, and less CPU time(s) comparing to other schemes.

Traffic congestion is a significant issue in urban areas. Realistic traffic flow models are crucial for understanding and mitigating congestion. Congestion occurs at bottlenecks where large changes in density occur. In this paper, a traffic flow model is proposed which characterizes traffic at the egress and ingress to bottlenecks. This model is based on driver response which includes driver reaction and traffic stimuli. Driver reaction is based on time headway and driver behavior which can be classified as sluggish, typical or aggressive. Traffic stimuli are affected by the transition width and changes in the equilibrium velocity distribution. The explicit upwind difference scheme is used to evaluate the Lighthill, Whitham, and Richards (LWR) and proposed models with a continuous injection of traffic into the system. A stability analysis of these models is given and both are evaluated over a road of length 10 km which has a bottleneck. The results obtained show that the behavior with the proposed model is more realistic than with the LWR model. This is because the LWR model cannot adequately characterize driver behavior during changes in traffic flow.

The Digital Total Variation (DTV) scheme is a digitized energy regularization scheme used for image denoising. This technique takes advantage of being applied to arbitrarily located data points and also has the edge detective property. This article aims to introduce a novel meshless scheme using DTV filtering and Radial Basis Functions (RBFs) to solve the associated equation with the DTV model numerically which results in the image denoising to remove additive noise from image information. This meshless algorithm based on local collocation and Multiquadric Radial Basis Function. These appearances allow this algorithm not only to remove the additive noise from images but also to resolve the discontinuities sharply. It is also noticed that the proposed meshless scheme is simple, fast, computationally effective, requires simply post-processing, and can be easily implemented mathematically. Experimental results confirm that the peak signal-to-noise ratio, the structural similarity, signal-to-noise ratio, the visual effect, and the computational performance of this new meshless scheme are improved compared with state-of-the-art denoising schemes. Furthermore, the proposed scheme can be applied to colour images as well.

Carbon quantum dots (CQDs) are a new type of nano-carbons that are currently favored over semiconductor quantum dots (QDs) because of their solubility, low toxicity, eco-friendliness, and cheap and facile synthesis giving desired optical characteristics. Moreover, their physiochemical properties can be controlled by their synthetic route. CQDs can emit fluorescence in the range from the UV to the near-infrared (NIR) region, making them suitable for biomedical applications. Fluorescence in these nano-carbon atoms can be tuned by varying the excitation wavelength. As of now, CQDs have been used in various applications such as in bioimaging, biosensing, electrochemical biosensing, drug delivery, gene delivery, photodynamic therapy in the treatment of cancers, pharmaceutical formulations, and treating inflammation. This article highlights the current progress and advancement of CQDs with focus on their synthetic routes, chemical and optical properties, and biomedical applications along with new perceptions in this interesting and promising field.

Background: Painful Diabetic Neuropathy (PDN) is a devastating condition affecting one in three people with diabetes. Introduction: Keeping in mind the unceasingly escalating prevalence of diabetes mellitus worldwide, the number of PDN patients is also expected to rise with a reduced quality of life in patients and a staggering increase in healthcare costs. Despite relentless efforts and continuous research, the commercially available medications for relieving diabetic neuropathy pain are only partially effective with substantial side effects. This is, in part, due to our partial awareness of the underlying complexities causing PDN. The pathogenesis of PDN remains elusive because of the difficulty in obtaining damaged nerve samples and the absence of non-invasive methods to investigate the pathogenesis at different stages of disease progression. The purpose of this review was to describe pathogenesis, clinical manifestations and treatment options for PDN. Methods: The keywords relevant to the scope of this paper were put in electronic databases (PubMed and Google Scholar) to fetch the relevant data. The data were then analyzed and compiled. Results: A simplified overview of PDN for researchers new to the field has been provided in an attempt to clarify common confusions. The changes in skin structure and functions in response to diabetes, diabetic neuropathy and painful diabetic neuropathy are also discussed. The unavailability of an efficacious pain reliever for PDN stresses on the need for identifying the microenvironmental factors that are altered in PDN and manipulate them to tailor targeted theranostics. Conclusion: In the end, we proposed to consider the altered skin structure, function and microenvironmental factors in the diabetic population for devising smart, targeted, stimuli-responsive treatment options to attain maximum pain relief with minimum side effects.

Two oilseed rape genotypes (Jiu-Er-13XI and Zheyou-50), differing in seed oil content, were subjected to cadmium (Cd) stress in hydroponic experiment. Genotypic differences were observed in terms of tolerance to Cd exposure. Cd treatment negatively affected both genotypes, but the effects were more devastating in Jiu-Er-13XI (low seed oil content) than in Zheyou-50 (high seed oil content). Jiu-Er-13XI accumulated more reactive oxygen species (ROS), which destroyed chloroplast structure and decreased photosynthetic pigments, than Zheyou-50. Total fatty acids, especially 18:2 and 18:3, severely decreased as suggested by increase in MDA content. Roots and shoots of Jiu-Er-13XI plants accumulated more Cd content, while less amount of tocopherol (Toc) was observed under Cd stress, than Zheyou-50. Conversely, Zheyou-50 was less affected by Cd stress than its counterpart. It accumulated comparatively less amount of Cd in roots and shoots, along with reduced accumulation of malondialdehyde (MDA) and ROS under Cd stress, than Jiu-Er-13XI. Further, the level of Toc, especially α-Tocopherol, was much higher in Zheyou-50 than in Jiu-Er-13XI, which was also supported by high expression of Toc biosynthesis genes in Zheyou-50 during early hours. Toc not only restricted the absorption of Cd by roots and its translocation to shoot but also scavenged the ROS generated during oxidative stresses. The low level of MDA shows that polyunsaturated fatty acids in chloroplast membranes remained intact. In the present study the tolerance of Zheyou-50 to Cd stress, over Jiu-Er-13XI, is attributed to the activities of Toc. This study shows that plants with high seed oil content are tolerant to Cd stress due to high production of Toc.

PurposeThe fabrication and characterization of a hydrogel-based conductometric sensor have been carried out. The purpose of this research is to fabricate a small robust hydrogel-based conductometric sensor for real-time monitoring of pH in the physiological range.Design/methodology/approachA pH-responsive Chitosan/Gelatin composite hydrogel has been used for this purpose. This study reports and analyzes the sensing response obtained from four hydrogel compositions with varying Chitosan/Gelatin ratios. The pH-responsive nature of the hydrogel has been mapped out through volumetric and conductometric tests. An attempt has been made to correlate these characteristics with the physico-chemical nature of the hydrogel through scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction techniques.FindingsThe four hydrogel compositions differed on the basis of gel composition ratios; the conductometric analysis results prove that the sensor with the hydrogel composition (Chitosan 2 per cent, Gelatin 7 per cent, ratio 1:2) produces the best pH resolution in the pH range of 4 to 9. The sensing mechanisms and the differences obtained between individual sensor outputs have been discussed in detail. On the basis of this extensivein vitroassessment, it has been concluded that while key pendant functional groups contribute to pH-responsive characteristics of the hydrogel, the overall sensitivity of the sensors gel component to surrounding pH is also determined by the crystalline to amorphous ratio of the hydrogel composite, its interpenetrating cross-linked structure and the relative ratio of the hydrophilic to the pH-sensitive components.Practical implicationsThe conductometric sensor results prove that the fabricated sensor with the shortlisted hydrogel composition shows good sensitivity in the physiological pH range (4 to 9) and it has the potential for use in point of care medical devices for diagnostic purposes.Originality/valueThis is the first reported version of the fabrication and testing and analysis/comparison of a hydrogel-based conductometric sensor based on this composition. The work is original and has not been replicated anywhere.

A family $\mathcal {G}$ of connected graphs is a family with unbounded metric dimension if $dim (\text{G})$ is not constant and depends on the order of graph. In this paper, we compute the metric dimension of the splitting graphs $S(P_{n})$ and $S(C_{n})$ of a path and cycle. We prove that the metric dimension of these graphs varies and depends on the number of vertices of the graph.

Drug delivery systems (DDSs) are a promising avenue for targeted drug delivery over a given time frame. Different techniques have been devised for drug encapsulation in a delivery system which can carry it to the target site and release it as a function of time. The biochemical properties of encapsulation systems are tailored according to the required release profile for the target tissue. Electrospun fibers have been greatly investigated recently for the development of DDSs. Different applications for specific fiber types have been fabricated and tested in order to determine their clinical significance. This review critically analyzes the potential applications of electrospun fibers in drug delivery system (DDS).

Background and objective Systemic lupus erythematosus (SLE) is a diverse autoimmune disorder, evoked in response to self-immune system that leads to immune complex depositions and organ damage. The exact mechanism of SLE pathogenesis is still unclear but certain genetic and environmental factors have been suggested that could influence its pathogenesis. Discussion The modulation in B- and T- cell responses and genetic variations could lead to abnormal lymphocyte functions and the production of antibodies against the indigenous proteins and the immune complex depositions. Conclusion The present review highlights the various causatives of SLE, particularly the genetic alteration in B- and T-cell-related proteins. We have also delineated some of the available therapeutic strategies for the treatment of SLE.

Interleukin-10 (IL-10) is an anti inflammatory cytokine involved in the ongoing coronary inflammation and related patho-physiological processes. The piece of work presented herein is aimed at investigating possible association of polymorphisms in IL-10 promoter with Saudi cardiovascular disease (CVD) patients. The study included 80 confirmed CVD patients with diabetes and 75 healthy control individuals both men and women. Concentration of IL-10 in the serum samples were measured by ELISA method. For single nucleotide polymorphism (SNP) analysis, Sanger method of DNA sequencing was followed. The IL-10 level was found to be significantly elevated in CVD patients (P < 0.001) and its associated complications viz. ST-elevation myocardial infarction [STEMI] (P

Flax (Linum usitatissimum) is a member of family linaceae with annual growth habit. It is included among those crops which were domesticated very early and has been used in development related studies as a model plant. In plants, Calmodulin-binding transcription activators (CAMTAs) comprise a unique set of Calmodulin-binding proteins. To elucidate the transport mechanism of secondary metabolites in flax, a genome-based study on these transporters was performed. The current investigation identified nine CAMTAs proteins, classified into three categories during phylogenetic analysis. Each group had significant evolutionary role as illustrated by the conservation of gene structures, protein domains and motif organizations over the distinctive phylogenetic classes. GO annotation suggested a link to sequence-specific DNA and protein binding, response to low temperature and transcription regulation by RNA polymerase II. The existence of different hormonal and stress responsive cis-regulatory elements in promotor region may directly correlate with the variation of their transcripts. MicroRNA target analysis revealed that various groups of miRNA families targeted the LuCAMTAs genes. Identification of CAMTA genes, miRNA studies and phylogenetic analysis may open avenues to uncover the underlying functional mechanism of this important family of genes in flax.

Background Auxetic materials tend to exhibit stretching in the direction of the applied load as well as in the perpendicular direction. This may be an inherent property of the material, or it might be a particular structural characteristic that confers it with auxetic properties. In this study, the auxetic properties of a rotating squares auxetic design were utilized in tandem with a stretching mechanism to manufacture a device that offers the advantages of adjustable pore size and hence tunable drug delivery characteristics. Methods An auxetic polyurethane film was fabricated through the polymer casting technique. An acrylonitrile-butadiene-styrene (ABS) plastic mold for polymer casting was made through additive manufacturing. Stereolithography was used for fabrication of the mechanism that controlled pore size of the polymeric auxetic film. A laminate arrangement of the film and the mechanism was devised, through which movement of the mechanism controlled stretching of the auxetic film underneath. Results Results were analyzed through image processing. It was observed that a 2-dimensional increase (in length and width) of the auxetic film took place that corresponded to an increase in pore size of the film. Several mathematical correlations were drawn up. Conclusions It may be concluded that the first factor controlling drug release kinetics is the pore size of the film. This study explored a prototype mechanism that has the potential for being used in devices for controlled drug delivery or in smart bandage systems that may enhance wound healing in chronic wound treatment.

The design and fabrication of a wound healing device for chronic wounds, with multiple functions for controlled drug delivery and exudate removal, has been described in this paper. The structural features have been machined and modified through laser cutting in a biocompatible polymer cast. Miniaturized versions of electronically actuated (lead-screw and pulley) mechanisms are used for the specific purpose of controlled drug delivery. These mechanisms have been studied and tested, being controlled through a microcontroller setup. An auxetic polymeric barrier membrane has been used for restricting the drug quantities administered. Drug delivery mechanisms are powered wirelessly, through an external, active RF component; this communicates with a passive component that is buried inside the wound healing device. The exudate removal efficiency of the device has been assessed through several simple tests using simulated wound exudate. It has been found that reasonably precise quantities of drug dosages to be administered to the wound site can be controlled through both drug delivery mechanisms; however, the lead-screw mechanism provides a better control of auxetic barrier membrane actuation and hence controlled drug delivery. We propose that this device can have potential clinical significance in controlled drug delivery and exudate removal in the management of chronic wounds., Application of rotating squares auxetic geometry in precisely controlled drug delivery for potential use in wound management systems; a comparison between two electromechanically controlled mechanisms employing the auxetic rotating squares geometry.

Background Auxetics, a special class of materials, tend to expand both in the radial and longitudinal directions when a unidirectional tensile force is applied. Recently, studies have come up with new designs for auxetic vascular and nonvascular stents which are deployed with commercial balloon catheters. There are some inherent limitations associated with a unidirectional application of expansion force in the effective deployment of stents. This work proposed a solution to some of these limitations through the use of a biaxial mode of a predetermined strain-based expansion mechanism. Method The design incorporated a pressure-activated crank-slider mechanism. Fabrication of a prototype for experimental verification was carried out through milling and high-speed lathe machining. The testing of the device employed the use of auxetic stents, fabricated from a biocompatible polymer. A finite element study is presented to extrapolate experimental results to a broader range of operation and working conditions. Results and Conclusions The expansion mechanism is similar in operation to the opening of an umbrella. The length of the connected auxetic stent increases when internal hydraulic pressure is applied. The degree of linear expansion in 1 direction influences the expansion of auxetic stent in the lateral direction. As the device exerts pressure longitudinally, a larger amount of the force is distributed on the unit cells/hinges which ultimately results in an increased expansion of the stent.

A new compound 1-(4-methoxyphenyl)-3-(pyridine-3-ylmethyl)thiourea was synthesized and structure of compound (3) was elucidated by FT-IR, 1 H-NMR, and mass spectrophotometer. The computational quantum chemical studies of compound (3) like, IR, UV, NBO analysis were performed by DFT with B3LYP exchange-correlation functional in combination with 6–311++G(d, p) basis sets. The compound (3) adopted syn-anti-configuration around sulphur atom, possessing stablization relative energy -740715 kcal/mol. The chemical potential of compound (3) is −3.37 eV and chemical hardness is −2.33 eV. However, ionization and electron affinity of compound (3) are −5.70 eV and −1.04 eV. The compound (3) was docked with B-DNA (1BNA) and the binding energy was found to be -7.41 kcal/mol . The nitrogen atom of thiourea of compound (3) binds with O3 and O4 of cytosine of A strand of DNA having bond lengths (1.92 A) and (1.74 A) respectively Furthermore, DNA binding constant was performed by UV–visible spectrophotometer. The binding constant was found 3.71 × 10 6 Lmol −1 . In order to assess cytotoxic nature of the lead compound, MTT-assay was performed against MCF-7 cell line and IC 50 value of compound (3) was observed at 160.97 μ M. Theoretical studies revealed that they are good agreement with experimental results.

An unsteady squeezing flow of Casson fluid having magnetohydrodynamic (MHD) effect and passing through porous medium channel is modeled and investigated. Similarity transformations are used to convert the partial differential equations (PDEs) of non-Newtonian fluid to a highly nonlinear fourth-order ordinary differential equation (ODE). The obtained boundary value problem is solved analytically by Homotopy Perturbation Method (HPM) and numerically by explicit Runge-Kutta method of order 4. For validity purpose, we compare the analytical and numerical results which show excellent agreement. Furthermore, comprehensive graphical analysis has been made to investigate the effects of various fluid parameters on the velocity profile. Analysis shows that positive and negative squeeze numberSqhave opposite effect on the velocity profile. It is also observed that Casson parameterβshows opposite effect on the velocity profile in case of positive and negative squeeze numberSq. MHD parameterMgand permeability constantMphave similar effects on the velocity profile in case of positive and negative squeeze numbers. It is also seen that, in case of positive squeeze number, similar velocity profiles have been obtained forβ,Mg, andMp. Besides this, analysis of skin friction coefficient has also been presented. It is observed that squeeze number, MHD parameter, and permeability parameter have direct relationship while Casson parameter has inverse relationship with skin friction coefficient.

INTRODUCTION Injuries cover about 11% of World's Disease Burden depicting fractures to be the leading severe consequence of trauma. Fractures occur due to force impact or osteoporosis. Fracture healing is a complicated process. Fracture fixation techniques focus on imparting reduction to fractured fragments and induce healing. When considering possible fixation methods, the aspect of micro-movement is an important one, as this induces callus formation which tends to be a crucial step for fracture healing. Internal fixation of long bone fractures using metallic plates has been carried out since decades and recently advancements have been in synthesizing biodegradable plates as well. The purpose of this research was to fabricate an Auxetic Polymeric Bone Plate that can be used as an internal fixator for long bone fracture; this bone plate renders micro-movement due to its counter intuitive behavior, has the potential to reduce the effect of stress shielding and allow the same range of motion as that of natural bone. METHODS Polyurethane was chosen as a material for the fabrication of the Auxetic device because of its biocompatibility and non-toxic effects. The plate was then tested for mechanical properties such as Tensile and Compression testing to determine the strength. RESULTS AND DISCUSSION The tensile testing of the Auxetic polyurethane specimens showed that the mean of the Poisson's ratio of the samples lies between -0.68 and -0.87 at different uni-axial tensile load values. The Auxetic structure of our device has the potential to allow for efficient fixation because its negative Poisson's ratio offers micro-movement, thereby causing fixation with relative stability rather than absolute stability. The Auxetic bone plate can be superior to contemporary plate fixation systems, as it demands meaningfully small contact points. The suitable mechanical properties might lessen stress shielding effects that are normally caused by rigid bone plates. The Auxetic nature of the bone will help align and sustain the bone fragments with small fracture gaps in order to impart appropriate assembly to accomplish bone healing.

Squamous cell carcinoma is usually cancer of the upper oesophagus and is very aggressive cancer. The cancer of the cervical oesophagus causes a serious complication called dysphagia, which is difficulty in eating or swallowing and which is indicative of incurability. Oesophageal stents have been used as a relatively better palliative method for patients who are suffering from advanced stage squamous cell carcinomas of oesophagus and also for the effective relief of dysphagia. There are still problems in currently available self-expanding metals and plastic stents, which are associated with high rates of early and late complications. This research work is aimed to use Auxetic (rotating-squares) geometry for the production of a novel Auxetic oesophageal stents and stent-grafts relevant to the palliative treatment of squamous cell carcinomas of the proximal and mid oesophagus and also for the prevention of dysphagia. This study also endeavoured to manufacture a significantly small diameter Auxetic oesophageal stent and stent-graft. In order to easily deploy the Auxetic stent orally using a commercial balloon dilatational catheter, and hence it also obviates the need of an expensive dedicated delivery system. A novel manufacturing route was employed in this research to develop both Auxetic films and Auxetic oesophageal stents, which ranged from conventional subtractive techniques to new generative manufacturing methods. Polyurethane was selected as a material for the fabrication of Auxetic films and Auxetic oesophageal stents because of its good biocompatibility and non-toxicological properties. The developed Auxetic films were later used for the fabrication of seamed Auxetic oesophageal stents. The flexible polyurethane tubular grafts were also attached to the inner luminal side of the seamless Auxetic oesophageal stents, in order to prevent tumour in-growth.

Fracture fixation techniques, fracture management, and orthopedic trauma care have evolved, and various advancements have been made in the last 50 years. Minimally invasive biological osteosynthetic devices have the potential of transforming the prospects of orthopedic treatment. Internal fixation techniques offer tremendous advantages in the management of bone fractures. The main objective of this study was to fabricate a novel auxetic polymeric bone stent with potential applications in internal fixation procedures. A new “connected stars” geometry has been used for the fabrication of this device. After fabrication, the mechanical characterization of the auxetic bone stent was also carried out to study its properties and deformation behavior. The research work undertaken also assesses the potential for auxetic behavior of these tubular structures.

Background Cardiovascular heart disease is one of the leading health issues in the present era and requires considerable health care resources to prevent it. The present study was focused on the development of a new coronary stent based on novel auxetic geometry which enables the stent to exhibit a negative Poisson's ratio. Commercially available coronary stents have isotropic properties, whereas the vascular system of the body shows anisotropic characteristics. This results in a mismatch between anisotropic–isotropic properties of the stent and arterial wall, and this in turn is not favorable for mechanical adhesion of the commercially available coronary stents with the arterial wall. It is believed that an auxetic coronary stent with inherent anisotropic mechanical properties and negative Poisson's ratio will have good mechanical adhesion with the arterial wall. Methods The auxetic design was obtained via laser cutting, and surface treatment was performed with acid pickling and electropolishing, followed by an annealing process. In vitro mechanical analysis was performed to analyze the mechanical performance of the auxetic coronary stent. Scanning electronic microscopy (SEM) was used to determine the effects of fabrication processes on the topography of the auxetic stent. Results and Conclusions The elastic recoil (3.3%) of the in vitro mechanical analysis showed that the auxetic stent design effectively maintained the luminal patency of the coronary artery. Also, the auxetic coronary stent showed no foreshortening, therefore it avoids the problem of stent migration, by expanding in both the radial and longitudinal directions. By virtue of its synclastic behavior, the auxetic stent bulges outward when it is radially expanded through an inflated balloon.