149 results on '"Hassan, Mohammad"'
Search Results
2. Detection and characterization of multidrug resistant Escherichia coli carrying virulence gene isolated from broilers in Bangladesh.
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Islam, Md. Sirazul, Nath, Chandan, Hasib, F. M. Yasir, Logno, Tahia Ahmed, Uddin, Md. Helal, Hassan, Mohammad Mahmudul, and Chowdhury, Sharmin
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ESCHERICHIA coli ,POLYMERASE chain reaction ,DRUG resistance in microorganisms ,DRUG resistance in bacteria ,ERYTHROMYCIN - Abstract
Background: The emergence and dissemination of multidrug resistant (MDR) bacteria pose a severe threat to public health by limiting clinical treatment and prophylactic options. Objectives: This study investigates the prevalence of Escherichia coli in broilers, their phenotypic antimicrobial resistance (AMR) profiles and the presence of virulence‐associated genes (VAGs) and antimicrobial resistance genes (ARGs) using polymerase chain reaction (PCR). Materials and methods: A total of 216 pooled cloacal samples were collected from 1080 broilers across six districts of Bangladesh. Each pooled sample comprised randomly selected cloacal swabs from five birds per farm. E. coli isolates were identified using standard bacteriological approach, followed by biochemical assays and PCR. Antimicrobial susceptibility was assessed using the Kirby–Bauer disc diffusion method, and the presence of ARGs and VAGs was determined via PCR. Five selected isolates were partially sequenced for five VAGs using Sanger sequencing. Results: A total of 177 E. coli isolates (81.94%, 95% confidence interval: 76.24%–86.53%) were identified. The isolates showed the highest resistance to ampicillin (93.79%), followed by tetracycline (91.53%), erythromycin (89.27%) and ciprofloxacin (87%). Conversely, ceftriaxone (80.79%) showed highest susceptibility, followed by gentamicin (37.29%) and neomycin (31.07%). All isolates were MDR, with a multiple antibiotic resistance indexes were <0.3. A significant percentage (16.38%) of E. coli isolates were MDR to five antimicrobial classes and harboured blaTEM, sul1, ere (A), tetA, tetB and tetC genes. The highest prevalent ARGs were blaTEM (88.14%) followed by ere (A) (83.62%) and sul 1 (72.32%). The prevalence of VAGs was astA (56.50%), iucD (31.07%), iss (21.47%), irp2 (15.82%) and cva/cvi (3.39%), respectively. Conclusions: This study highlights the presence of ARGs contributing to the development of MDR in E. coli carrying VAGs in broilers. Effective monitoring and surveillance of antimicrobial usage in poultry production systems are urgently required to prevent emergence and dissemination of AMR. [ABSTRACT FROM AUTHOR]
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- 2024
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3. A novel triage framework for emergency department based on machine learning paradigm.
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Menshawi, Alaa Mohammad and Hassan, Mohammad Mehedi
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ARTIFICIAL neural networks , *EMERGENCY medical services , *MEDICAL personnel , *FEATURE selection , *ARTIFICIAL intelligence - Abstract
Emergency departments, crucial in managing patient emergencies, are often challenged by overcrowding and diagnostic errors during triage—the process that assesses the urgency of patients' conditions. Traditional triage systems, heavily dependent on human judgement, are prone to errors like under‐triage, where severe conditions are missed, delaying treatment, and over‐triage, where less severe conditions are overly prioritized, causing unnecessary resource use and morbidity. This thesis presents a novel multi‐model machine‐learning framework designed to enhance triage accuracy by evaluating multiple medical conditions concurrently, including chronic illnesses like heart disease. The framework employs various machine‐learning techniques—such as logistic regression, support vector machines, random forests, deep neural networks, and decision trees—to analyze different medical conditions in two comprehensive phases. In the first phase, patients' conditions are categorized, and a multi‐tiered analysis using multiple classifiers refines the assessment by considering probabilistic outcomes from each classifier. The second phase synthesizes these insights into a unified and precise triage decision, distinguishing between patients who require critical care and those needing less urgent hospitalization. This integration of diverse machine learning models allows for a fused and precise triage decision, overcoming traditional triage systems' limitations that usually focus on single conditions and rely on isolated model predictions. A hybrid feature selection method is also utilized to identify critical predictors, enhancing the decision‐making process. The framework is validated through a specially curated dataset that simulates multiple triage scenarios, evaluated by medical experts for efficacy. Comparative analysis with traditional triage methods demonstrates significant improvements in decision accuracy, as evidenced by higher area under curve (AUC) values—0.95 for critical care and 0.90 for hospitalization. The implementation of this data‐driven approach substantially reduces human error, boosts operational efficiency, and aids medical staff in making rapid, informed decisions. This research represents a significant advancement in emergency medical care, illustrating the benefits of integrating sophisticated machine learning techniques to improve patient outcomes and resource management. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Deep Reinforcement Learning‐Based Multireconfigurable Intelligent Surface for MEC Offloading.
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Qu, Long, Huang, An, Pan, Junqi, Dai, Cheng, Garg, Sahil, Hassan, Mohammad Mehedi, and Jiang, Weiwei
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REINFORCEMENT learning ,DEEP reinforcement learning ,MOBILE computing ,EDGE computing ,NUMERICAL analysis ,SEMIDEFINITE programming - Abstract
Computational offloading in mobile edge computing (MEC) systems provides an efficient solution for resource‐intensive applications on devices. However, the frequent communication between devices and edge servers increases the traffic within the network, thereby hindering significant improvements in latency. Furthermore, the benefits of MEC cannot be fully realized when the communication link utilized for offloading tasks experiences severe attenuation. Fortunately, reconfigurable intelligent surfaces (RISs) can mitigate propagation‐induced impairments by adjusting the phase shifts imposed on the incident signals using their passive reflecting elements. This paper investigates the performance gains achieved by deploying multiple RISs in MEC systems under energy‐constrained conditions to minimize the overall system latency. Considering the high coupling among variables such as the selection of multiple RISs, optimization of their phase shifts, transmit power, and MEC offloading volume, the problem is formulated as a nonconvex problem. We propose two approaches to address this problem. First, we employ an alternating optimization approach based on semidefinite relaxation (AO‐SDR) to decompose the original problem into two subproblems, enabling the alternating optimization of multi‐RIS communication and MEC offloading volume. Second, due to its capability to model and learn the optimal phase adjustment strategies adaptively in dynamic and uncertain environments, deep reinforcement learning (DRL) offers a promising approach to enhance the performance of phase optimization strategies. We leverage DRL to address the joint design of MEC‐offloading volume and multi‐RIS communication. Extensive simulations and numerical analysis results demonstrate that compared to conventional MEC systems without RIS assistance, the multi‐RIS‐assisted schemes based on the AO‐SDR and DRL methods achieve a reduction in latency by 23.5% and 29.6%, respectively. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Osmoregulatory and immunological role of new canceled cells: Mitochondrial rich cells and its future perspective: A concise review.
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Ali, Waseem, Chen, Yan, Hassan, Mohammad Farooque, Wang, Tao, Khatyan, Uzma, Sun, Jian, Liu, Zongping, and Zou, Hui
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MALE reproductive organs ,SPERMATOZOA ,SEX hormones ,MITOCHONDRIA ,EXOCRINE secretions - Abstract
Mitochondrial‐rich cells (MRCs) are one of the most significant canceled type of epithelial cells. Morphologically these cells are totally different from other epithelial cells. These cells primarily implicated in sea‐water and fresh‐water adaptation, and acid–base regulation. However, in this review paper, we explored some of the most intriguing biological and immune‐related functional developmental networks of MRCs. The main pinpoint, MRCs perform a dynamic osmoregulatory and immunological functional role in the gut and male reproductive system. The Na+/K+_ATPase (NKA) and Na+/K+/2Cl cotransporter (NKCC) are key acidifying proteins of MRCs for the ion‐transporting function for intestinal homeostasis and maintenance of acidifying the luminal microenvironment in the male reproductive system. Further more importantly, MRCs play a novel immunological role through the exocrine secretion of nano‐scale exosomes and multivesicular bodies (MVBs) pathway, which is very essential for sperm maturation, motility, acrosome reaction, and male sex hormones, and these an essential events to produce male gametes with optimal fertilizing ability. This effort is expected to promote the novel immunological role of MRCs, which might be essential for nano‐scale exosome secretion. Highlights: Mitochondrial rich cells (MRCs) are mostly observed in the fish and reptiles MRCs are canceled type of epithelial cells.MRCs perform biological and immunological advance networks.MRCs secret acidifying proteins in the male reproductive system. [ABSTRACT FROM AUTHOR]
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- 2024
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6. 3D Printing‐Enabled Design and Manufacturing Strategies for Batteries: A Review.
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Fonseca, Nathan, Thummalapalli, Sri Vaishnavi, Jambhulkar, Sayli, Ravichandran, Dharneedar, Zhu, Yuxiang, Patil, Dhanush, Thippanna, Varunkumar, Ramanathan, Arunachalam, Xu, Weiheng, Guo, Shenghan, Ko, Hyunwoong, Fagade, Mofe, Kannan, Arunchala M., Nian, Qiong, Asadi, Amir, Miquelard‐Garnier, Guillaume, Dmochowska, Anna, Hassan, Mohammad K., Al‐Ejji, Maryam, and El‐Dessouky, Hassan M.
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- 2023
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7. The One Health Epidemiology of Avian Influenza Infection in Bangladesh: Lessons Learned from the Past 15 Years.
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Hassan, Mohammad Mahmudul, Dutta, Pronesh, Islam, Md Mazharul, Ahaduzzaman, Md., Chakma, Shovon, Islam, Ariful, and Magalhaes, Ricardo J. Soares
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AVIAN influenza epidemiology , *AVIAN influenza , *AVIAN influenza A virus , *POULTRY farming , *VIRUS virulence , *VIRAL transmission - Abstract
Avian influenza viruses (AIVs) are significant transboundary zoonotic pathogens that concern both animal and human. Since the first report of H5N1 AIV in Bangladesh in early 2007, it resulted in numerous outbreaks across the country, hindering the sustainable growth of the poultry industry through economic losses in different production systems (commercial and backyard). Highly pathogenic avian influenza (HPAI) virus and low pathogenic avian influenza (LPAI) virus are currently cocirculating and causing infection in poultry sectors in an endemic manner in Bangladesh as well as in wild bird species. The introduction of multiple clades of H5N1 in different poultry species and the reassortment of AIVs with different patterns of infections have complicated the epidemiological situation for control and created conditions to increase the virulence of the virus, host range, and potential zoonotic transmission. The risk of viral transmission at the human–poultry interface is increasing over time due to inadequate surveillance and early detection strategies and practices, ineffective biosecurity practices among poultry raisers, and the complex supply chains of backyard and commercial poultry and live bird market (LBM) systems. Improving AIV surveillance in poultry flocks and LBMs, vaccination, biosecurity, and awareness among poultry professionals is beneficial to controlling the disease burden in the poultry sector. However, human cases of AIV related to poultry production and marketing chain in Bangladesh suggest a One Health approach engaging various stakeholders from the public and private would be a better option for successfully controlling avian influenza outbreaks in Bangladesh. This review of literature presents the comprehensive overview of AIV infection status in Bangladesh, including a description of pathways for zoonotic transmission at different epidemiological interfaces, the genetic evolution of the virus, and the need for improvement of disease control strategies incorporated with early detection, application of effective vaccines, increases the proper biosecurity practices and improvement of awareness among the poultry raisers, traders and consumers using a One Health approach. [ABSTRACT FROM AUTHOR]
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- 2023
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8. Epidemiology and Evolutionary Dynamics of High Pathogenicity Avian Influenza (HPAI) H5N1 in Bangladesh.
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Islam, Ariful, Ara, Tasnim, Amin, Emama, Islam, Shariful, Sayeed, Md. Abu, Shirin, Tahmina, Hassan, Mohammad Mahmudul, Klaassen, Marcel, and Epstein, Jonathan H.
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DISEASE clusters ,AVIAN influenza ,INFECTIOUS disease transmission ,EPIDEMIOLOGY ,BAYESIAN analysis ,PREVENTIVE medicine ,POULTRY farms - Abstract
Understanding disease clustering and transmission patterns improves the prevention and control of disease. Herein, we described the epizootic characteristics and spatiotemporal dynamics of High Pathogenicity Avian In3uenza (HPAI) H5N1 outbreaks as well as clade diversity and phylodynamics of H5N1 over time and across host species in Bangladesh. We used Moran's I, Geary's C, Getis-Ord Gi_, and a space-time permutation model to analyze the spatiotemporal patterns of H5N1 outbreaks. We used Bayesian phylogenetic analysis to generate a time-scaled maximum clade credibility (MCC) tree. Our study revealed nine HPAI H5N1 epizootic waves between 2007 and 2020 that invariably peaked in the wintertime. After vaccination of poultry against H5N1 was introduced in 2012, the incidence of HPAI H5N1 outbreaks and poultry mortality decreased signi>cantly over time. Nonetheless, our research revealed that the virus continued circulating unabatedly in Bangladesh. +e various spatiotemporal analyses were identi>ed up to nine space-time clusters across Bangladesh, with the most signi>cant clustering and hotspots of H5N1 outbreaks in and around the district of Dhaka. Since 2007, four H5N1 clades have been detected in Bangladesh, with only clade 2.3.2.1a continuing to circulate since 2011, which was followed up by the reassorted clade 2.3.2.1a in 2012. +e HA gene of the H5N1 clade 2.3.2.1a has been reassorted into at least nine subgroups (R1-R9). After 2016, the >rst eight groups disappeared, with only the R9 group remaining. Spatiotemporal patterns and phylodynamics of H5N1 outbreaks are crucial for developing targeted and appropriate HPAI control and prevention measures. We recommended intensive monitoring of biosecurity measures and disease records in high-priority areas, along with assessing vaccine eBcacy to better control HPAI outbreaks in Bangladesh. [ABSTRACT FROM AUTHOR]
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- 2023
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9. Prevalence of gastrointestinal parasitic infections in wild mammals of a safari park and a zoo in Bangladesh.
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Ferdous, Sabrina, Chowdhury, Joya, Hasan, Tanjila, Dutta, Pronesh, Rahman, Md. Mizanur, Hassan, Mohammad Mahmudul, Faruque, Md. Rayhan, and Alim, Mohammad Abdul
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OMNIVORES ,PARASITIC diseases ,CAPTIVE wild animals ,ZOOS ,SAFARIS ,MAMMALS - Abstract
In safari parks and zoos, wild animals are kept mainly for recreational purposes. Animals in these enclosures are also crucial for the education, research, and conservation aspect. To ensure better management and good health of wild animals in captivity, it is essential to monitor the occurrence of gastrointestinal (GI) parasitic (helminths and protozoa) infections. The current investigation was undertaken to investigate the prevalence of GI parasitic infections in wild mammals at Bangabandhu Sheikh Mujib (BSM) safari park and Chattogram (CTG) zoo of Bangladesh. A total of 72 individual faecal samples were collected from 25 species of wild mammals. Routine qualitative (e.g. direct smear, sedimentation, and flotation) and quantitative (e.g. McMaster technique) tests were performed to identify the eggs or oocysts of helminths and protozoa. Results demonstrated that wild mammals of both BSM safari park and CTG zoo were infected with a total of 17 genera/species of helminths and protozoa. The overall prevalence of GI parasitic infections in wild mammals of both zoological parks was 65.3% (95% confidence interval [CI]: 53.14–76.12), whereas it was 72.4% (95% CI: 52.76–87.27) in the BSM safari park and 60.5% (95% CI: 44.41–75.02) in the CTG zoo. In both zoological parks, infection with nematodes was more frequent compared to other helminth into the wild mammals. The herbivores were more infected with GI parasites than carnivores and omnivores of both BSM safari park and CTG zoo. The mean eggs/oocysts per gram of faeces was the highest in the carnivores compared to herbivores and omnivores of both enclosures. The findings of the current study demonstrated that wild mammals of both BSM safari park and CTG zoo suffered from various GI parasitic infections. Regular monitoring along with proper therapeutic measures may reduce the severe consequences of GI parasitic infections in captive wild animals. [ABSTRACT FROM AUTHOR]
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- 2023
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10. Prevalence of helminth and protozoan infections in pet birds of Chattogram, Bangladesh.
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Bayzid, Mohammad, Yasir Hasib, Farazi Muhammad, Hasan, Tanjila, Hassan, Mohammad Mahmudul, Masuduzzaman, Mohammad, Hossain, Mohammad Alamgir, and Alim, Mohammad Abdul
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HELMINTHS ,PROTOZOAN diseases ,HELMINTHIASIS ,BIRD infections ,PARASITIC diseases ,INTESTINAL infections - Abstract
Background: Parasitic diseases such as helminths and protozoa are considered one of the major impediments in the rearing of pet birds. The current study was undertaken to determine the prevalence of helminths and protozoal infections in different captive pet birds in Chattogram metropolitan area, Bangladesh. Methods: A total of 549 pooled faecal and 311 individual blood samples were collected from different species of pet birds during June 2019 to May 2020. The faecal samples were examined following routine microscopic tests to identify the eggs and oocysts of helminths and protozoan parasites, respectively. Polymerase chain reaction (PCR) was performed to determine the haemoprotozoan parasites. Results: The prevalence of helminth infestations in pet birds was 8.01% (95% confidence interval [CI]: 5.88–10.61), where infestation caused by nematodes was the highest (7.47%, CI: 5.41–10). Ascaridia and Capillaria spp. infestations were the commonest helminths recorded in different groups of pet birds. The overall prevalence of intestinal protozoal infections was 11.11% (CI: 8.61–14.04) in pet birds. The most commonly occurring protozoal infections were Eimeria spp. (7.83%, CI: 5.73–10.41) followed by Isospora spp. (2.91%, CI: 1.67–4.69). The overall prevalence of haemoprotozoan parasites was 2.25% (CI: 0.91–4.58) in different groups of pet birds. The highest prevalence was recorded in Plasmodium spp. (1.29%, CI: 0.35–3.26) followed by Leucocytozoon and Haemoproteus spp. Conclusions: The data generated in this study are the first of its type, which would be beneficial to the veterinary practice, aviculturists, pet bird owners and breeders in Bangladesh to respond appropriately for the prevention and control of the disease. [ABSTRACT FROM AUTHOR]
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- 2023
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11. Corruption and bank efficiency: Expanding the 'sand or grease the wheel hypothesis' for the Gulf Cooperation Council.
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Hassan, Mohammad Kabir, Hasan, Rashedul, Miah, Mohammad Dulal, and Ashfaq, Muhammad
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ISLAMIC finance , *BANKING industry , *CORRUPTION , *BANKING policy , *SAND - Abstract
We draw upon the broader theoretical framework of rent‐seeking to empirically analyze the impact of corruption on the efficiency of the banking industry in the Gulf Cooperation Council. We have used various databases, including Bankscope, World Bank, and Transparency International, to gather Bank‐specific and macro‐economic data for 77 banks covering the period 2005–2014. We perform ordinary least square (OLS) and generalised methods of moments regression (GMM) using a balanced panel and find (1) Islamic banks as less efficient and stable as compared to conventional banks in the GCC region, (2) corruption has a negative (positive) impact on Islamic (conventional) banks' stability. Our findings provide support for the 'sand the wheel' hypothesis of corruption for Islamic banks. This finding supports the view that under the current weak governance structures and complex policy framework, corruption acts as an 'escape hatch' for conventional banks. Our empirical findings could pave the way for further policy reform for the banking sector in the GCC region. [ABSTRACT FROM AUTHOR]
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- 2022
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12. High‐lignin‐content rice straw cellulose nanofibers/graphene oxide nanocomposites films: Electrical and mechanical properties.
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Abdel‐Aal, Seham K., Hassan, Mohammad L., Abou Elseoud, Wafaa S., and Ward, Azza
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RICE straw ,GRAPHENE oxide ,OXIDE coating ,ELECTRICAL conductivity measurement ,CELLULOSE ,LIGNIN structure ,CELLULOSE fibers ,NANOFIBERS - Abstract
Rice straw nanofibers (RSNF) with high lignin content were used in making nanocomposites with graphene oxide (GO) at loading ratios from 0.625% to 5% (based on weight of RSNF). The prepared RSNF/GO films were characterized regarding their tensile strength, equilibrium moisture content (EMC), and electrical properties. Microstructure of the films was examined using scanning electron microscopy (SEM). Addition of 2.5% of GO resulted in increasing tensile strength and Young's modulus by 33.5% and 21.5%, respectively. Presence of GO significantly reduced moisture sorption of the films. Electrical conductivity measurement showed significant increase in permittivity (ε′) upon increasing GO loading. The ionic conductivity value of films containing 5% of GO was 10−7 S cm−1, which is acceptable value for use as antistatic and/or dissipated films. The electrical properties of the prepared low‐cost high‐lignin‐content RSNF/GO films could have potential use in flexible electronic applications such as in energy harvesting and storage. [ABSTRACT FROM AUTHOR]
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- 2022
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13. Yield Response of Different Rice Ecotypes to Meteorological, Agro-Chemical, and Soil Physiographic Factors for Interpretable Precision Agriculture Using Extreme Gradient Boosting and Support Vector Regression.
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Ahmed, Md. Sabbir, Tazwar, Md. Tasin, Khan, Haseen, Roy, Swadhin, Iqbal, Junaed, Rabiul Alam, Md. Golam, Hassan, Md. Rafiul, and Hassan, Mohammad Mehedi
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PRECISION farming ,STANDARD deviations ,RICE ,MACHINE learning - Abstract
The food security of more than half of the world's population depends on rice production which is one of the key objectives of precision agriculture. The traditional rice almanac used astronomical and climate factors to estimate yield response. However, this research integrated meteorological, agro-chemical, and soil physiographic factors for yield response prediction. Besides, the impact of those factors on the production of three major rice ecotypes has also been studied in this research. Moreover, this study found a different set of those factors with respect to the yield response of different rice ecotypes. Machine learning algorithms named Extreme Gradient Boosting (XGBoost) and Support Vector Regression (SVR) have been used for predicting the yield response. The SVR shows better results than XGBoost for predicting the yield of the Aus rice ecotype, whereas XGBoost performs better for forecasting the yield of the Aman and Boro rice ecotypes. The result shows that the root mean squared error (RMSE) of three different ecotypes are in between 9.38% and 24.37% and that of R-squared values are between 89.74% and 99.13% on two different machine learning algorithms. Moreover, the explainability of the models is also shown in this study with the help of the explainable artificial intelligence (XAI) model called Local Interpretable Model-Agnostic Explanations (LIME). [ABSTRACT FROM AUTHOR]
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- 2022
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14. Transmission dynamics and susceptibility patterns of SARS‐CoV‐2 in domestic, farmed and wild animals: Sustainable One Health surveillance for conservation and public health to prevent future epidemics and pandemics.
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Islam, Ariful, Ferdous, Jinnat, Islam, Shariful, Sayeed, Md. Abu, Rahman, Md. Kaisar, Saha, Otun, Hassan, Mohammad Mahmudul, and Shirin, Tahmina
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PUBLIC health surveillance ,SARS-CoV-2 ,BATS ,CAPTIVE wild animals ,WILDLIFE conservation ,INFECTIOUS disease transmission ,COVID-19 - Abstract
The exact origin of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‐CoV‐2) and source of introduction into humans has not been established yet, though it might be originated from animals. Therefore, we conducted a study to understand the putative reservoirs, transmission dynamics, and susceptibility patterns of SARS‐CoV‐2 in animals. Rhinolophus bats are presumed to be natural progenitors of SARS‐CoV‐2‐related viruses. Initially, pangolin was thought to be the source of spillover to humans, but they might be infected by human or other animal species. So, the virus spillover pathways to humans remain unknown. Human‐to‐animal transmission has been testified in pet, farmed, zoo and free‐ranging wild animals. Infected animals can transmit the virus to other animals in natural settings like mink‐to‐mink and mink‐to‐cat transmission. Animal‐to‐human transmission is not a persistent pathway, while mink‐to‐human transmission continues to be illuminated. Multiple companions and captive wild animals were infected by an emerging alpha variant of concern (B.1.1.7 lineage) whereas Asiatic lions were infected by delta variant, (B.1.617.2). To date, multiple animal species – cat, ferrets, non‐human primates, hamsters and bats – showed high susceptibility to SARS‐CoV‐2 in the experimental condition, while swine, poultry, cattle showed no susceptibility. The founding of SARS‐CoV‐2 in wild animal reservoirs can confront the control of the virus in humans and might carry a risk to the welfare and conservation of wildlife as well. We suggest vaccinating pets and captive animals to stop spillovers and spillback events. We recommend sustainable One Health surveillance at the animal–human–environmental interface to detect and prevent future epidemics and pandemics by Disease X. [ABSTRACT FROM AUTHOR]
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- 2022
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15. Continuous Nanoparticle Patterning Strategy in Layer‐Structured Nanocomposite Fibers.
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Xu, Weiheng, Franklin, Rahul, Ravichandran, Dharneedar, Bawareth, Mohammed, Jambhulkar, Sayli, Zhu, Yuxiang, Kakarla, Mounika, Ejaz, Faizan, Kwon, Beomjin, Hassan, Mohammad K., Al‐Ejji, Maryam, Asadi, Amir, Chawla, Nikhilesh, and Song, Kenan
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VAPOR-plating ,POLYVINYL alcohol ,SOFT robotics ,NANOCOMPOSITE materials ,HEAT exchangers ,BORON nitride ,FIBERS - Abstract
Anisotropic polymer/nanoparticle composites display unique mechanical, thermal, electrical, and optical properties depending on confirmation and configuration control of the composing elements. Processes, such as vapor deposition, ice‐templating, nanoparticle self‐assembly, additive manufacturing, or layer‐by‐layer casting, are explored to design and control nanoparticle microstructures with desired anisotropy or isotropy. However, limited attempts are made toward nanoparticle patterning during continuous fiber spinning due to the thin‐diameter cross section and 1D features. Thus, this research focuses on a new patterning technique to form ordered nanoparticle assembly in layered composite fibers. As a result, distinct layers can be retained with innovative tool design, unique material combinations, and precise rheology control during fiber spinning. The layer multiplying‐enabled nanoparticle patterning is demonstrated in a few material systems, including polyvinyl alcohol (PVA)–boron nitride (BN)/PVA, polyacrylonitrile (PAN)–aluminum (Al)/PAN, and PVA–BN/graphene nanoplatelet (GNP)/PVA systems. This approach demonstrates an unprecedentedly reported fiber manufacturing platform for well‐managed layer dimensions and nanoparticle manipulations with directional thermal and electrical properties that can be utilized in broad applications, including structural supports, heat exchangers, electrical conductors, sensors, actuators, and soft robotics. [ABSTRACT FROM AUTHOR]
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- 2022
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16. Major bat‐borne zoonotic viral epidemics in Asia and Africa: A systematic review and meta‐analysis.
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Khan, Shahneaz Ali, Imtiaz, Mohammed Ashif, Islam, Md Mazharul, Tanzin, Abu Zubayer, Islam, Ariful, and Hassan, Mohammad Mahmudul
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EPIDEMICS ,ZOONOSES ,VIRUS diseases ,EBOLA virus ,NIPAH virus ,COVID-19 ,RIFT Valley fever - Abstract
Bats are the natural reservoir host for many pathogenic and non‐pathogenic viruses, potentially spilling over to humans and domestic animals directly or via an intermediate host. The ongoing COVID‐19 pandemic is the continuation of virus spillover events that have taken place over the last few decades, particularly in Asia and Africa. Therefore, these bat‐associated epidemics provide a significant number of hints, including respiratory cellular tropism, more intense susceptibility to these cell types, and overall likely to become a pandemic for the next spillover. In this systematic review, we analysed data to insight, through bat‐originated spillover in Asia and Africa. We used STATA/IC‐13 software for descriptive statistics and meta‐analysis. The random effect of meta‐analysis showed that the pooled estimates of case fatality rates of bat‐originated viral zoonotic diseases were higher in Africa (61.06%, 95%CI: 50.26 to 71.85, l2% = 97.3, p < 0.001). Moreover, estimates of case fatality rates were higher in Ebola (61.06%; 95%CI: 50.26 to 71.85, l2% = 97.3, p < 0.001) followed by Nipah (55.19%; 95%CI: 39.29 to 71.09, l2% = 94.2, p < 0.001), MERS (18.49%; 95%CI: 8.19 to 28.76, l2% = 95.4, p < 0.001) and SARS (10.86%; 95%CI: 6.02 to 15.71, l2% = 85.7, p < 0.001) with the overall case fatality rates of 29.86 (95%CI: 29.97 to 48.58, l2% = 99.0, p < 0.001). Bat‐originated viruses have caused several outbreaks of deadly diseases, including Nipah, Ebola, SARS and MERS in Asia and Africa in a sequential fashion. Nipah virus emerged first in Malaysia, but later, periodic outbreaks were noticed in Bangladesh and India. Similarly, the Ebola virus was detected in the African continent with neurological disorders in humans, like Nipah, seen in the Asian region. Two important coronaviruses, MERS and SARS, were introduced, both with the potential to infect respiratory passages. This paper explores the dimension of spillover events within and/or between bat–human and the epidemiological risk factors, which may lead to another pandemic occurring. Further, these processes enhance the bat‐originated virus, which utilises an intermediate host to jump into human species. [ABSTRACT FROM AUTHOR]
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- 2022
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17. Linkage‐Specific Synthesis of Di‐ubiquitin Probes Enabled by the Incorporation of Unnatural Amino Acid ThzK.
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Zhou, Han, Carpenter, Tomaya, Fu, Xuan, Jin, Bo, Ody, Britton, Hassan, Mohammad Sazid, Jacobs, Savannah E., Cheung, Jenny, Nicholson, Eve M., Turlington, Mark, Zhao, Bo, Lorenz, Sonja, Cropp, T. Ashton, and Yin, Jun
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- 2022
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18. In situ synthesized amphiphilic polysulfone‐poly(ethylene‐glycol) block copolymer/silver nanocomposite for separating oil/water emulsion.
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Elgawady, Yara, Ponnamma, Deepalekshmi, Hassan, Mohammad K., Adham, Samer, Karim, Alamgir, and Al‐Maadeed, Mariam Al Ali
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BLOCK copolymers ,ANTIMICROBIAL polymers ,NANOCOMPOSITE materials ,GLASS transition temperature ,TENSILE strength ,EMULSIONS ,SODIUM bromide - Abstract
This work reports the synthesis of silver nanoparticles from the precursors, silver nitrate and sodium bromide, and the in situ synthesis of polysulfone (PSf)‐poly(ethylene‐glycol) (PEG) block copolymer (BCP) in the presence of developed Ag. The PSf‐PEG BCP nanocomposite containing 3 wt.% of the nanoparticles, when electrospun, is observed to be helpful in separating the oil‐in‐water emulsion. Mechanical properties such as dynamic mechanical strength and tensile strength measurements and high thermal degradation temperature (~6°C) illustrate the reinforcing effect of the Ag nanoparticles. The presence of Ag influences the glass transition temperature (Tg) of the BCP and its elasticity due to its well distribution in the BCP during the in situ synthesis of nanocomposite. Electrospun fiber mat of the in situ synthesized PSf‐PEG/Ag nanocomposite shows improved wettability as evident from the respective aqueous contact angle values of 80.66° ± 1.3, 85.70° ± 2.0, and 101.50° ± 1.0 for PSf‐PEG/Ag, PSf‐PEG, and neat PSf. The combination of PEG to PSf has increased the overall polymer reinforcement effect, and this property along with the antimicrobial activity (inhibited growth of Staphylococcus aureus) of Ag nanoparticles are applied in developing bio‐fouling resistant BCP nanocomposite fibers for oil/water emulsion separation. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
19. Why do sukuks (Islamic bonds) need a different pricing model?
- Author
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Uddin, Md Hamid, Kabir, Sarkar H., Kabir Hassan, Mohammad, Hossain, Mohammed S., and Liu, Jia
- Subjects
ISLAMIC bonds ,RISK premiums ,BOND prices ,LIBOR ,GLOBAL Financial Crisis, 2008-2009 ,FAIR value ,BONDS (Finance) ,INFORMATION asymmetry - Abstract
The global interest in sukuk, an Islamic alternative to bond financing, has grown rapidly, particularly after the 2008 global financial crisis, due to its distinctive features and investment quality. Sukuk were first launched in Malaysia and are presently available in 29 countries, including the United Kingdom, United States, Singapore, Hong Kong, and Luxembourg. Despite the global market prevalence of sukuk, asset pricing literature has not yet addressed the pricing mechanism of sukuk, which is inherently different from bonds and equity due to the contractual differences. However, analysts use LIBOR, or the Islamic interbank benchmark rate, as the ad‐hoc benchmark to evaluate sukuk performance. In this study, we develop a basic pricing model that captures the common risks in sukuk returns. We identify two risk factors for sukuk that require risk premiums: (a) sukuk market risk and (b) information asymmetry risk. Using these two common sukuk risks factors, investment analysts can estimate the fair value of sukuk more precisely than other ad hoc measures available. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
20. Titanium Carbide (Ti3C2Tx) MXene Ornamented with Palladium Nanoparticles for Electrochemical CO Oxidation.
- Author
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Salah, Belal, Eid, Kamel, Abdelgwad, Ahmed M., Ibrahim, Yasmeen, Abdullah, Aboubakr M., Hassan, Mohammad K., and Ozoemena, Kenneth I.
- Subjects
TITANIUM carbide ,NANOPARTICLES ,DECORATION & ornament ,REDUCING agents ,CATALYSTS ,PALLADIUM ,SONICATION ,OXIDATION - Abstract
Titanium carbide (Ti3C2Tx) MXene possesses various unique physicochemical and catalytic properties. However, the electrochemical CO oxidation performance is not yet addressed experimentally. Herein, Ti3C2Tx (TX=OH, O, and F) ordered and exfoliated two‐dimensional nanosheets ornamented with semi‐spherical palladium nanoparticles (2.5 Wt. %) with an average diameter of (10±1 nm) (denoted as Pd/Ti3C2Tx) is rationally designed for the electrochemical CO oxidation. The fabrication process is based on the selective chemical etching of Ti3AlC2 and delamination under sonication to form Ti3C2Tx nanosheets that are used as a substrate and reducing agent for supporting in situ growth of Pd nanoparticles via impregnation with Pd salt. Interestingly, Pd‐free Ti3C2Tx displayed inferior CO oxidation activity, while Pd/Ti3C2Tx enhanced the CO oxidation activity substantially. This is attributed to the combination of outstanding physicochemical properties of Ti3C2Tx and the catalytic merits of Pd nanoparticles. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
21. Core-Shell Nanofibers of Polyvinyl Alcohol/Polylactic Acid Containing TiO2 Nanotubes for Natural Sunlight Driven Photocatalysis.
- Author
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Ponnamma, Deepalekshmi, Elgawady, Yara, Nair, Sabari S., Hassan, Mohammad K., and Al-Maadeed, Mariam Al Ali
- Subjects
POLYVINYL alcohol ,POLYLACTIC acid ,NANOTUBES ,PHOTOCATALYSIS ,NANOFIBERS ,SEWAGE - Abstract
Highly stable and efficient coaxial electrospun fibers of polyvinyl alcohol (PVA) and polylactic acid (PLA) nanocomposite filled with titanium dioxide (TiO
2 ) nanotubes areaccomplished for natural sunlight-driven photocatalytic dye degradation. The coaxial electrospinning process generates well-defined concentric cylinder-like morphology, with the polymeric core and sheath phases, with TiO2 present only in the outer phases. The nanofibers are characterized for their coaxial morphology and the distribution of TiO2 in the sample is monitored through EDAX studies. Coaxial electrospinning process influences the polymeric structural and functional performances, regulates the crystallization kinetics, and ensures the entanglement of TiO2 nanopowders without allowing them to leach out. Photodecomposition of Rhodamine B and methylene blue dye are observed by the UV--visible studies and ≈80% and ≈85% degradation is achieved respectively after 8 h. A higher efficiency of degradation is achieved for the TiO2 nanocomposites, due to the photocatalytic activity of the TiO2 semiconductors, and also because of its presence in the sheath phase. The efficiency of dye degradation is correlated with the mechanical and dynamic mechanical properties of the fibers and with the typical fiber morphology and spinning mechanism. While the dye molecules get trapped in the porous sites of composite fibers, the TiO2 radicals initiates the photocatalysis process. The current technology is promising in manipulating flexible, durable, and environmentally friendly polymer nanocomposite fibers for industrial wastewater purification. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
22. Prevalence and diversity of gastrointestinal parasites in free‐ranging rhesus macaques (Macaca mulatta) in different land gradients of Bangladesh.
- Author
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Islam, Shariful, Rahman, Md. Kaisar, Uddin, Md. Helal, Rahman, Md. Mustafizur, Chowdhury, Mohammad N. U., Hassan, Mohammad M., Magalhaes, Ricardo S., and Islam, Ariful
- Subjects
MACAQUES ,RHESUS monkeys ,LIVESTOCK parasites ,PARASITES ,LOGISTIC regression analysis ,DOMESTIC animals - Abstract
Rhesus macaques are considered an important reservoir of different gastrointestinal (GI) zoonotic parasites affecting livestock and humans. Loads of GI parasites in the free‐ranging rhesus macaques living in close proximity to communities in Bangladesh are still unknown. To estimate the prevalence and diversity of zoonotic GI parasites in rhesus macaques of Bangladesh, a total of 182 freshly voided fecal samples were collected from macaques living in rural (N = 67), peri‐urban (N = 57), urban (N = 28), and Safari park (N = 30) between October 2015 and December 2016. All samples were tested by direct smear, sedimentation, flotation, and the McMaster techniques. A total of fourteen different taxa of GI parasites were detected, revealing an overall prevalence of 54.4% (n = 99; 95% confidence interval [CI]: 46.9–61.8). The prevalence of GI parasites was found to be significantly correlated with the mean parasitic taxa per individual in a group (r = 0.90; p = 0.002). The multivariable logistic regression analysis showed that the overall prevalence of GI parasites in macaques was significantly higher in those inhabiting rural areas (62.69%; odds ratio [OR]: 7.22; p = 0.001) and in macaques with interactions with other animals (60.98%; OR: 5.49; p = 0.005). Our results also indicated that the prevalence of Strongyloides spp. and Balantidium coli infections varied significantly between land gradients. Our results also indicate that macaques frequently visit human settlements for food and are found interacting with domestic animals. In conclusion, the high prevalence of zoonotic GI parasite infection in rhesus macaques found in our study may pose a significant public health risk to communities, particularly in rural areas of Bangladesh. Health promotion to at‐risk communities focusing on limiting contact with rhesus macaques is necessary to mitigate potential zoonotic transmission. Research highlights: Fourteen different taxa of gastrointestinal (GI) parasites were detected, revealing an overall prevalence of infection of 54.4%.Significantly higher prevalence of GI parasites in macaques inhabiting rural areas, where macaques frequently interact with humans and other animals.High prevalence of diverse GI parasite infestation in rhesus macaques might have a public health concern in Bangladesh. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
23. Changes of Land Use and Land Cover with the Diversity of Fishes, Aquatic Plants, and Bird's Species at Wetland Ecosystem.
- Author
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Alam, Mohammad Zahangeer, Baki Bhuiyan, Md. Abdullahil, Abdullah, Hasan Muhammad, Ghosh, Suma Rani, Hassan, Mohammad Maksudul, Akter, Ruzina, Rokonuzzaman, M., and Alam, Mohammad Shah
- Subjects
LAND use ,LAND cover ,AQUATIC plants ,WETLAND ecology ,CLASSIFICATION of fish ,BIRD classification ,PLANT classification ,ANIMAL populations ,ECOSYSTEMS ,ANIMALS - Abstract
Bangladesh is rich in wetland biodiversity with aquatic plants, fishes, and birds. Mohanganj Upazila is known as the capital of lower Bangladesh. The present study focuses on the changes of land use and land cover (LULC) with a diversity of species that are being least concerned (LC), vulnerable (VU), and endangered (EN). Over the last two decades, the wetland species of Mohanganj were gradually declined. Our results showed that 19 fish, 4 aquatic plants, and 7 bird species were LC in 2015. Among the fish and aquatic plant species, 6 fish species (Wallago attu, Ompok pabda, Channa punctate, Chitala chitala, Salmostoma phulo, and Corica soborna) and 2 aquatic plant species (Nymphaea nouchali and Nymphaea lotus) were VU during the dry and rainy season of 2017 and 2019, respectively. In the dry season of 2019, 4 fish species (W. attu, O. pabda, C. punctate, and Ch. chitala), 2 aquatic plant species (N. nouchali and N. lotus), and 7 bird species (Anas platyrhynchos, Ardeola grayii, Gyps bengalensis, Alcedo atthis, Phalacrocorax fuscicollis, Porphyrio porphyria, and Larus ridibundus) were EN. Among the species, W. attu, N. nouchaii, G. bengalensis, P. porphyria, and L. ridibundus were extremely endangered categories. Changes in LULC, the establishment of settlements for the increasing population, indiscriminate use of pesticides, environmental pollutions, and climate change are the potential reasons for declining trends of wetland biodiversity. Stern actions on land use policy, expansion of organic agriculture, bioremediation of industrial effluents, and adoption of sustainable environmental policies should be taken by the Government of Bangladesh for immediate conservation of wetland biodiversity. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
24. Effect of poly(ε‐caprolactone) and titanium (IV) dioxide content on the UV and hydrolytic degradation of poly(lactic acid)/poly(ε‐caprolactone) blends.
- Author
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Luyt, Adriaan Stephanus, Antunes, Ana, Popelka, Anton, Mahmoud, Abdelrahman, Hassan, Mohammad Korany, and Kasak, Peter
- Subjects
LACTIC acid ,CHAIN scission ,DIFFERENTIAL scanning calorimetry ,TITANIUM ,POLYCAPROLACTONE ,NUCLEAR forces (Physics) ,POLYMER blends - Abstract
The effect of accelerated weathering degradation on the properties of poly(lactic acid) (PLA)/poly(ε‐caprolactone) (PCL) blends and PLA/PCL/titanium (IV) dioxide (TiO2) nanocomposites are presented in this paper. The results show that both polymers are susceptible to weathering degradation, but their degradation rates are different and are also influenced by the presence of TiO2 in the samples. Visual, microscopic and atomic force microsocpy observations of the surface after accelerated weathering tests confirmed that degradation occurred faster in the PLA/PCL blends than in the PLA/PCL/TiO2 nanocomposites. The X‐ray diffraction results showed the degradation of PCL in the disappearance of its characteristic peaks over weathering time, and also confirmed that PLA lost its amorphous character and developed crystals from the shorter chains formed as a result of degradative chain scission. It was further observed that the presence of TiO2 retarded the degradation of both PLA and PCL. These results were supported by the differential scanning calorimetry results. The thermogravimetric analysis results confirmed that that PLA and PCL respectively influenced each other's thermal degradation, and that TiO2 played a role in the thermal degradation of both PLA and PCL. The tensile properties of both PLA/PCL and PLA/PCL/TiO2 were significantly reduced through weathering exposure and the incorporation of TiO2. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
25. Geospatial dynamics of COVID‐19 clusters and hotspots in Bangladesh.
- Author
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Islam, Ariful, Sayeed, Md. Abu, Rahman, Md. Kaisar, Ferdous, Jinnat, Islam, Shariful, and Hassan, Mohammad Mahmudul
- Subjects
COVID-19 ,COVID-19 pandemic ,INFECTIOUS disease transmission ,VIRAL transmission ,SCAN statistic - Abstract
The coronavirus disease 2019 (COVID‐19) is an emerging and rapidly evolving profound pandemic, which causes severe acute respiratory syndrome and results in significant case fatality around the world including Bangladesh. We conducted this study to assess how COVID‐19 cases clustered across districts in Bangladesh and whether the pattern and duration of clusters changed following the country's containment strategy using Geographic information system (GIS) software. We calculated the epidemiological measures including incidence, case fatality rate (CFR) and spatiotemporal pattern of COVID‐19. We used inverse distance weighting (IDW), Geographically weighted regression (GWR), Moran's I and Getis‐Ord Gi* statistics for prediction, spatial autocorrelation and hotspot identification. We used retrospective space‐time scan statistic to analyse clusters of COVID‐19 cases. COVID‐19 has a CFR of 1.4%. Over 50% of cases were reported among young adults (21–40 years age). The incidence varies from 0.03 ‐ 0.95 at the end of March to 15.59–308.62 per 100,000, at the end of July. Global Moran's Index indicates a robust spatial autocorrelation of COVID‐19 cases. Local Moran's I analysis stated a distinct High‐High (HH) clustering of COVID‐19 cases among Dhaka, Gazipur and Narayanganj districts. Twelve statistically significant high rated clusters were identified by space‐time scan statistics using a discrete Poisson model. IDW predicted the cases at the undetermined area, and GWR showed a strong relationship between population density and case frequency, which was further established with Moran's I (0.734; p ≤ 0.01). Dhaka and its surrounding six districts were identified as the significant hotspot whereas Chattogram was an extended infected area, indicating the gradual spread of the virus to peripheral districts. This study provides novel insights into the geostatistical analysis of COVID‐19 clusters and hotspots that might assist the policy planner to predict the spatiotemporal transmission dynamics and formulate imperative control strategies of SARS‐CoV‐2 in Bangladesh. The geospatial modeling tools can be used to prevent and control future epidemics and pandemics. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
26. Inhibition of osteoclast activities by SCPC bioceramic promotes osteoblast‐mediated graft resorption and osteogenic differentiation.
- Author
-
El‐Ghannam, Ahmed, Nakamura, Miho, Muguruza, Leire Bergara, Sarwar, Uruj, Hassan, Mohammad, Fotawi, Randa Al, and Horowitz, Robert
- Abstract
Maximizing vital bone in a grafted site is dependent on a number of factors. These include resorption or turnover of the graft material, stimulation of bone formation pathway without a need for biological molecules added to the site and inhibition of cellular activities that compromise the mineralization of new bone matrix. In the present study, the dissolution profile of silica‐calcium phosphate composite (SCPC) in physiological solution was measured and the data were fed to (ANN‐NARX) prediction model to predict the time required for complete dissolution. The inductively coupled plasma‐optical emission spectrometer ionic composition analysis of the culture medium incubated for 3 days with SCPC showed 57% decrease in Ca concentration and a significant increase in the concentration of Si (13.5 ± 1.8 μg/ml), P (249.4 ± 22 μg/ml), and Na (9.3 ± 0.52 μg/ml). In conjunction with the release of Si, P, and Na ions, the bone resorptive activity of osteoclasts was inhibited as indicated by the significant decrease in multinucleated tartrate resistant acidic phosphate stained cells and the volume of resorption pits on bone slices. In contrast, addition of SCPC to hBMSC cultured in conventional medium promoted higher Runt‐related transcription factor 2 (p <.05), osteocalcin (p <.01), and bone sialo protein (p <.01) than that expressed by control cells grown in the absence of SCPC. The predicted dissolution time of 200 mg of porous SCPC particles in 10 ml phosphate buffered saline is 6.9 months. An important byproduct of the dissolution is inhibition of osteoclastic activity and promotion of osteoblastic differentiation and hence bone formation. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
27. An efficient framework for integrating distributed generation and capacitor units for simultaneous grid‐connected and islanded network operations.
- Author
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Leghari, Zohaib Hussain, Hassan, Mohammad Yusri, Said, Dalila Mat, Memon, Zeeshan Anjum, and Hussain, Saddam
- Subjects
- *
CAPACITOR banks , *CAPACITORS , *NETWORK performance , *REACTIVE power , *MATHEMATICAL optimization , *ALGORITHMS - Abstract
Summary: This paper proposes a two‐stage planning approach for the efficient utilization of distributed generation (DG) and capacitor banks (CBs) for the simultaneous grid‐connected and islanded operations of the balanced distribution networks. The first stage determines the optimal installation locations and capacities of DGs and CBs using an improved variant of the Jaya optimization algorithm (IJaya) to minimize the power losses and voltage deviation during the grid‐connected operation of the distribution network. The second stage identifies the optimal operating point of the DG and CB combination to carry the maximum load during the islanded network operation under power supply‐demand imbalance conditions. For the second stage, an analytical approach is proposed to identify the best operating power factor for the DG‐CB combination, calculating the power loss, and under‐utilization of the installed real‐reactive power sources. Simulation results on the IEEE 33‐bus grid‐dependent distribution network demonstrate that the proposed IJaya significantly improved the network performance and outperforms various existing optimization methods. In addition, during the network's islanded operation, maintaining the network power factor equal to the source power factor (pfsource) makes the DG‐CB combination operate at their rated capacities. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
28. Real‐time multiperiod voltage control algorithm with OLTC and switched capacitors for smart distribution networks in the presence of energy storage system.
- Author
-
Olatunde, Oladepo, Hassan, Mohammad Y., Abdullah, Md P., and Rahman, Hasimah A.
- Subjects
- *
ENERGY storage , *VOLTAGE control , *CAPACITOR switching , *ALGORITHMS , *MULTIAGENT systems , *RENEWABLE energy sources - Abstract
Summary: Conventionally, voltage profile are regulated by controllers that are not operational flexible to the system dynamism and challenges offered by the integration of renewable energy sources. Consequently, there is a need for the adaptive coordinating mechanism as an interface between the passive network and the new active network. This will provide a platform for the smooth integration of distributed energy resources in most developing countries where traditional network is still operational. This paper proposes an algorithm for real‐time multiperiod adaptive compensation of network reactive power support based on hierarchical structure and decentralized layered multiagent system voltage coordinating scheme. A multiperiod voltage control algorithm replicates the daily load flow evaluation aiming at ameliorating voltage fluctuation over a 24‐hour simulation period. The algorithm applies the decentralized voltage control mechanism to monitor the network parameters and dynamically evaluate the capacity of the capacitor banks (CBs) to be injected for voltage compensation. This mitigates the challenges associated with under and over reactive power compensation experienced in the day‐ahead programming and manual switching operation. The algorithm works in conjunction with an on‐load tap changing transformer (OLTC) and energy storage system (ESS). The ESS complements the OLTC during switching delay, dip in its output root mean square and voltage fluctuation as network loading condition varies. The effectiveness of the proposed method is verified on standard IEEE 33 and 118‐bus distribution systems. The results show an improved voltage performance and reduction in stress/complexity associated with load and renewable generation forecast in manual switching operations. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
29. Characterization of polysulfone/diisopropylamine 1‐alkyl‐3‐methylimidazolium ionic liquid membranes: high pressure gas separation applications.
- Author
-
Khraisheh, Majeda, Zadeh, Khadija M., Alkhouzaam, Abedalkhader I., Turki, Dorra, Hassan, Mohammad K., Momani, Fares Al, and Zaidi, Syed M. J.
- Subjects
LIQUID membranes ,IONIC liquids ,DYNAMIC mechanical analysis ,MEMBRANE separation ,DIELECTRIC measurements - Abstract
Membrane separation is gaining great attention in many applications, especially in gas separation. Polysulfone (PSF) is the most widely studied polymeric membrane material for CO2 in its pure or modified state. Ionic liquids supported membrane technology (SILMs) are now widely applied due to their unique properties at room temperatures. In our previous study, we proved the enhanced ability of ionic liquid enhanced PSF for the separation of CO2 from gas streams. In this study, the dielectric measurements (BDS) extending up to 107 Hz for different concentrations of ionic liquid into PSF matrix, are presented. Thermogravimetric analysis measurement (TGA), differential scanning calorimeter (DSC), dynamic mechanical analysis, and the tensile properties of the membranes are studied in order to optimize the efficiency of separating CO2 from CO2/N2 mixture and CO2/CH4. TGA showed that pure PSF is a highly thermostable polymer, of which the 5% weight loss temperature is above 150°C. DSC traces show that the Tg of PSF was 149.5°C and decreases gradually for the composites. This behavior was confirmed with BDS analyses, which also revealed important information about the chain motions dynamics and the fragility index. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
30. Virtual inertial support extraction using a super‐capacitor for a wind‐PMSG application.
- Author
-
Hasan, Nor Shahida, Rosmin, Norzanah, Nordin, Norjulia Mohamad, and Hassan, Mohammad Yusri
- Abstract
The replacement of a conventional synchronous generator (SG) with higher wind penetration greatly reduces the inertial support available for the system. Therefore, a new consideration – the dynamic frequency changes in a wind energy system using a super‐capacitor (SC) – is proposed here to provide faster, limitless, inertial response during load disturbances. By considering the dynamic frequency change in defining the power exchange between SC and network, this proposed method not only provides inertial and primary frequency response but is also able to avoid a second frequency dip. To avoid deep charge and discharge of SC, a simple energy management system (EMS) which considers the system frequency deviation and the state of charge (SOC) of SC is adopted in this technique. The effectiveness of the proposed technique is modelled in MATLAB/Simulink software. Comparative analyses between the proposed virtual inertial support (VIS)‐based SC and existing VIS control strategies are performed. The simulation results obtained prove that the proposed VIS greatly reduces the frequency nadir and peak frequency of the system during sudden load increase and decrease, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
31. Electrical conductivity and dielectric properties of nanofibrillated cellulose thin films from bagasse.
- Author
-
Abdel‐karim, Amal M., Salama, A. H., and Hassan, Mohammad L.
- Subjects
ELECTRIC conductivity ,DIELECTRIC properties ,CELLULOSE ,THIN films ,BAGASSE - Abstract
Abstract: Nanocelluloses are potential candidates for applications in flexible electronic due to their unique physical and mechanical properties. However, electrical properties of these materials have not investigated thoroughly to study their electrical properties. In the current work, electrical properties of nanocellulose films prepared from bagasse pulp were studied and compared with those of bagasse pulp fibers. Two kinds of nanocelluloses were used in the current study: microfibrillated cellulose (MFC) and TEMPO‐oxidized nanofibrillated cellulose (NFC). The crystallinity, grain size, and morphology of the different nanocelluloses were studied using X‐ray diffraction and transmission electron microscopy techniques. The dc‐, ac‐ electrical conductivity, dielectric constant ɛ′, and dielectric loss ɛ″ of non‐plasticized and glycerol‐plasticized nanocellulose films were studied in the temperature range from 298 to 373 K and in the frequency range from 0.1 KHz to 5 MHz. The results showed that the dc‐ electrical conductivity verifies Arrhenius equation and the activation energies varied in the range of 0.9 to 0.42 eV. Ac‐electrical conductivity increased with frequency and fitted with power law equation, which ensures that the conduction goes through hopping mechanism. The dielectric constant decreased with increasing frequency and increased with increasing temperature, probably due to the free movement of dipole molecular chains within the cellulose fiber. Glycerol‐plasticized NFC (NFC‐G) film had the highest dielectric constant and ac‐electrical conductivity values of 79 800 and 2.80× 10
−3 ohm−1 cm−1 , respectively. The high values of dielectric constant and conductivity of the prepared films support their use in electronic components. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
32. Assessment of transport stress on cattle travelling a long distance (≈648 km), from Jessore (Indian border) to Chittagong, Bangladesh.
- Author
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Alam, Mahabub, Hasanuzzaman, Md, Hassan, Mohammad Mahmudul, Rakib, Tofazzal Md, Hossain, Md Emran, Rashid, Md Harun, Sayeed, Md Abu, Philips, Lindsay B., and Hoque, Md Ahasanul
- Published
- 2018
- Full Text
- View/download PDF
33. Kinetic studies of POSS-DGEBA precursors derived from monoamine functional POSS using dynamic dielectric sensing and nuclear magnetic resonance.
- Author
-
Sharma, Amit K., Hassan, Mohammad K., Tu, Jianwei, Mauritz, Kenneth A., and Wiggins, Jeffrey S.
- Subjects
SILICONES ,CHEMICAL kinetics ,OLIGOMERS ,EPOXY compounds ,DISPERSION (Chemistry) ,DIELECTRICS - Abstract
Incorporation of pre-reacted monofunctional polyhedral oligomeric silsesquioxane (POSS)-epoxy adducts dramatically improves dispersion of POSS in epoxy-amine networks. The relationship between reaction kinetics and mechanism for formation of POSS-epoxy adducts versus reaction temperature was investigated. Reactivities of epoxy-monoamine functional POSS molecules were determined using in situ reaction monitoring by dynamic dielectric sensing and
29 Si NMR spectroscopy. The amine-functional POSS-epoxy isothermal reaction showed reduced reactivity due to reduced molecular mobility, that is, diffusion limitations. Kinetic parameters were determined by fitting29 Si NMR data to the model of Kamal that was extended to include diffusion. Fitting of this model to experimental data showed very good agreement over the entire conversion range for pre-reaction between amine-functionalized POSS and epoxy. An autocatalytic mechanism, the same as that for the neat epoxy-amine systems, was indicated. Gel permeation chromatography, scanning electron microscopy and transmission electron microscopy were used to investigate molecular weight evolution and morphology of final networks cured by 4,40 diaminodiphenyl sulfone using pre-reacted POSS-epoxy adducts. POSS aggregate size decreased with increased pre-reaction temperature, more homogenous POSS dispersion was observed with higher pre-reaction temperature. Dynamic mechanical analysis demonstrated that Tg of composites decreased slightly compared to that of the neat matrix and there appeared to be little change in microstructural heterogeneity. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
34. Polyaniline/Polystyrene Blends: In-Depth Analysis of the Effect of Sulfonic Acid Dopant Concentration on AC Conductivity Using Broadband Dielectric Spectroscopy.
- Author
-
Al-Thani, Noora, Hassan, Mohammad K., and Bhadra, Jolly
- Subjects
POLYANILINES ,DOPING agents (Chemistry) ,SULFONIC acids ,BROADBAND dielectric spectroscopy ,ALTERNATING currents - Abstract
This work presents an in-depth analysis of the alternating current (AC) conductivity of polyaniline-polystyrene (PANI-PS) blends doped with camphor sulfonic acid (CSA) and prepared using an in situ dispersion polymerization technique. We prepared the blends using fixed ratios of PS to PANI while varying the concentration of the CSA dopant. The AC conductivity of the blends was investigated using broadband dielectric spectroscopy. Increasing CSA resulted in a decrease in the AC conductivity of the blends. This behaviour was explained in terms of the availability of a lone pair of electrons of the NH groups in the polyaniline, which are typically attacked by the electron-withdrawing sulfonic acid groups of CSA. The conductivity is discussed in terms of changes in the dielectric permittivity storage (ε′), loss (ε′′), and modulus (M′′) of the blends over a wide range of temperatures. This is linked to the glass transition temperature of the PANI. Dielectric spectra at low frequencies indicated the presence of pronounced Maxwell-Wagner-Sillars (MWS) interfacial polarization, especially in samples with a low concentration of CSA. Electrical conduction activation energies for the blends were also calculated using the temperature dependence of the direct current (DC) conductivity at a low frequency (σdc), which exhibit an Arrhenius behaviour with respect to temperature. Scanning electron microscopy revealed a fibrous morphology for the pure PANI, while the blends showed agglomeration with increasing CSA concentrations. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
35. An efficient approach of improving privacy and security in online social networks.
- Author
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Almasoud, Suliman K., Almogren, Ahmad, Hassan, Mohammad Mehedi, and Alrassan, Iehab
- Subjects
DATA security ,ONLINE social networks ,SOCIAL interaction ,BUSINESS models ,INFORMATION theory - Abstract
Summary: Online social networks (OSNs) have become popular and widely used by many people nowadays. As those OSNs increase, the virtual social interactions have resulted in increasing privacy and security concern. Many approaches have been proposed in order to provide users with “better” privacy protection, but none of those approaches have “fully succeeded,” due to their conflict with service providers' economic benefits or due to the suggestion of changing the OSNs architecture. In this paper, we propose a new model that would improve privacy and security in OSNs by preventing users from revealing private and or confidential information online as possible. We endeavor to create a balance between privacy and security improvement versus the service provider business model. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
36. Computational and experimental exploration of the structure–activity relationships of flavonoids as potent glyoxalase‐I inhibitors.
- Author
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Al‐Balas, Qosay A., Hassan, Mohammad A., Al‐Shar'i, Nizar A., El‐Elimat, Tamam, and Almaaytah, Ammar M.
- Subjects
- *
GLYOXALASE , *CANCER treatment , *THERAPEUTIC use of coumarins , *FLAVONOIDS , *HYDROXYLATION , *THERAPEUTICS - Abstract
Abstract: Hit, Lead & Candidate Discovery Glyoxalase‐I (Glo‐I) enzyme has emerged as a potential target for cancer treatment. Several classes of natural products including coumarins and flavonoids have shown remarkable Glo‐I inhibitory activity. In the present study, computational and experimental approaches were used to explore the structure–activity relationships of a panel of 24 flavonoids as inhibitors of the Glo‐1 enzyme. Scutellarein with an IC50 value of 2.04 μM was identified as the most potent inhibitor among the series studied. Di‐ or tri‐hydroxylation of the benzene rings A and B accompanied with a C2/C3 double bond in ring C were identified as essential structural features for enzyme inhibition. Moreover, the ketol system showed a minor role in the inhibitory power of these compounds. The structure‐activity relationships revealed in this study had deepened our understanding of the Glo‐I inhibitory activities of flavonoids and opened the door for further exploration of this promising compound class. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
37. A scalable framework for protecting user identity and access pattern in untrusted Web server using forward secrecy, public key encryption and bloom filter.
- Author
-
Al‐Tariq, Abdullah, Kamal, Abu Raihan Mostofa, Hamid, Md. Abdul, Abdullah‐Al‐Wadud, M., Hassan, Mohammad Mehedi, and Rahman, SK Md. Mizanur
- Subjects
WEB-based user interfaces ,INTERNET servers ,COMPUTER access control ,PUBLIC key cryptography ,DATA security failures ,INFORMATION sharing ,CYBERTERRORISM ,COMPUTER security - Abstract
Securing user identity from data breach in a web server is one of the major concerns for the users of the web applications. Similarly, protecting user access pattern from unauthorized access should be taken seriously, because the potential threats such attacks may pose, are huge. However, these security measures should not be adopted at the expense of user experience and convenience. Nevertheless, any extra overhead in the form of security measures introduced in a distributed system results in significant performance declination. The target of a secured framework for a distributed system like web application should be a reasonable trade-off between security and user experience. Thus, in this work, we present a framework that ensures security for the user identity along with keeping the online activities of the users anonymous while ensuring scalability of the system. Our framework is designed in a scalable form that can work with other distributed architectures that provide security to user data and identities. To ensure all these measures, our proposal includes the implementation of Forward Secrecy using Diffie-Hellman Key exchange protocol where the server cannot remember a user's history after a session ends. In addition, we present our own mechanism to hide logical data sharing strategies to protect users against selective DoS attacks. Moreover, we implemented a modified version of bloom filter to safeguard user access pattern in a compromised server. Our proposed implementation of bloom filter also ensures that the scalability of distributed system is preserved even with little infrequent overhead in the server because of security measures proposed in this work. Finally, we implemented different modules of our framework using both Web Socket and Long Polling transport protocols and recorded the time required to perform various tasks. Web socket protocol took less time to perform each task than the long polling protocol, which is convincing enough to suggest that web socket performs better than long polling in the given scenarios. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
38. Energy-efficient multiperiod planning of optical core network to support 5 G networks.
- Author
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Li, Bingbing, Peng, Limei, Hao, Yixue, Miao, Yiming, and Hassan, Mohammad Mehedi
- Subjects
5G networks ,BANDWIDTH allocation ,MATHEMATICAL optimization - Abstract
With the rapid growth of traffic and power consumption in information and communication technology industry for decades, improving energy efficiency has become a challenging issue in recent years. Especially, the pervasive access to Internet via mobile devices will cause wireless traffic volume increment by 1000+ times in near future, which is expected to be carried by the fifth generation ultradense cellular network. Following this trend, the core network where optical fibers are deployed to deliver aggregated traffic needs upgrading to accommodate the increasing traffic volume. To match with the traffic growth rate, we should conduct efficient network planning over multiple time periods. Moreover, considering the heterogeneity in the bandwidth requirements among various network services, flexible mixed line rate scheme is adopted in network provisioning. In this paper, we study the long-term multiperiod planning of optical core network by considering the traffic growth with the objective of high energy-efficiency. Three planning strategies, say All-period, Incremental, and End-of-Life, respectively, are studied and formulated as mixed integer linear programming models with the objective to minimize power consumption of optical core network. Given the estimation on the reduction of power consumed by various network devices, we can deploy network devices flexibly in each period through the optimization models. Performance of the proposed models is also evaluated and compared via case studies. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
39. Synthesis and study on the binding of thiazol-2(3H)-ylidine derivative with human serum albumin using spectroscopic and molecular docking methods.
- Author
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Hassan, Mohammad Fahimul and Rauf, Abdul
- Abstract
In this article, a facile and convenient synthesis of thiazol-2(3H)-ylidine derivatives of fatty acid ( 3a- c) is described. The binding of N′-(4,5-dimethyl-3-penylthiazol-2(3H)-ylidine)octadec-9-enehydrazide ( 3a) with human serum albumin (HSA) is explored using various spectral methods and molecular docking. Fluorescence quenching results show that 3a induces conformational changes in HSA and the polarity around the tryptophan residues is increased. Stern-Volmer quenching plots at different temperatures (298, 305 and 312 K) show that the fluorescence quenching mechanism is static quenching. Synchronous fluorescence, 3D fluorescence spectra, circular dichroism and Fourier transform infrared spectroscopy are used to determine the structural change in HSA on interaction with 3a. Förster resonance energy transfer analysis shows that the binding distance ( r
0 = 2.78 nm) between HSA (Trp214) and 3a is within the of range 2-8 nm for quenching to occur. The molecular docking study also confirms that 3a is located in subdomain IIA (site I) of HSA and is stabilized by hydrogen bonding and hydrophobic forces. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
40. Processing, Dynamic mechanical thermal analysis, and dielectric properties of barium titanate/cellulosic polymer nanocomposites.
- Author
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Ali, Ashraf F., Hassan, Mohammad L., Ward, Azza A., and El‐Giar, Emad M.
- Subjects
- *
PERMITTIVITY , *NANOCOMPOSITE materials , *BARIUM titanate , *X-ray powder diffraction , *RAMAN spectroscopy - Abstract
High dielectric constant BaTiO3/ethyl cellulose (BT/EC) nanocomposites having BT loadings of up to 13 vol% were fabricated through a simple casting technique. The BT filler powder, synthesized through an ultrasonic-assisted solid-state route, was revealed by X-ray powder diffractometry (XRD) and Raman spectroscopy to be dominantly tetragonal. Scanning electron microscopy (SEM) showed good dispersion of the BT nanoparticles in the EC polymer matrix at lower BT concentrations. However, at higher concentrations, the BT particles form a continuous phase or a 'filler network' leading to weak BT/EC interactions. This finding is well supported by the results of the tensile strength and storage modulus. The dielectric properties of the BT/EC nanocomposites were investigated over wide ranges of frequency and temperature. The addition of BT significantly increased the permittivity ( ε′) and dielectric loss ( ε″) and improved the ionic conductivity of the EC. The electric modulus ( M″) results were analyzed in terms of the Havriliak-Negami function through three distinct relaxation mechanisms (namely α, β*, and β relaxations) in the temperature range 30-150°C. The dc conductivity ( σdc) results suggest that the BT/EC nanocomposites formed at low BT loading (up to 7.0 vol%) and a temperature of ≤60°C are good candidates for antistatic applications while those formed at higher concentrations and temperatures are recommended for use in electrostatic dissipation applications. POLYM. COMPOS., 38:893-907, 2017. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
41. Reputation-based credibility analysis of Twitter social network users.
- Author
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Alrubaian, Majed, Al‐Qurishi, Muhammad, Al‐Rakhami, Mabrook, Hassan, Mohammad Mehedi, and Alamri, Atif
- Subjects
TRUTHFULNESS & falsehood ,INTERNET users ,FORGING ,PERFORMANCE ,SOCIAL networks - Abstract
This paper addresses the problem of finding credible sources among Twitter social network users to detect and prevent various malicious activities, such as spreading false information on a potentially inflammatory topic, forging accounts for false identities, etc. Existing research works related to source credibility are graph-based, considering the relationships among users to predict the spread information; human-based, using human perspectives to determine reliable sources; or machine learning-based, relying on training classifiers to predict users' credibility. Very few of these approaches consider a user's sentimentality when analyzing his/her credibility as a source. In this paper, we propose a novel approach that combines analysis of the user's reputation on a given topic within the social network, as well as a measure of the user's sentiment to identify topically relevant and credible sources of information. In particular, we propose a new reputation metric that introduces several new features into the existing models. We evaluated the performance of the proposed metric in comparison with two machine learning techniques, determining that the accuracy of the proposed approach satisfies the stated purpose of identifying credible Twitter users. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
42. Secondary chain motion and mechanical properties of γ-irradiated-regenerated cellulose films.
- Author
-
Tanvir, Aisha, Al-Maadeed, Mariam A., and Hassan, Mohammad K.
- Published
- 2017
- Full Text
- View/download PDF
43. Maximizing quality of experience through context-aware mobile application scheduling in cloudlet infrastructure.
- Author
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Mahmud, Md. Redowan, Afrin, Mahbuba, Razzaque, Md. Abdur, Hassan, Mohammad Mehedi, Alelaiwi, Abdulhameed, and Alrubaian, Majed
- Subjects
CONTEXT-aware computing ,QUALITY of service ,MOBILE apps ,CLOUD computing software ,SIMULATION software ,COMPUTER software - Abstract
Application software execution requests, from mobile devices to cloud service providers, are often heterogeneous in terms of device, network, and application runtime contexts. These heterogeneous contexts include the remaining battery level of a mobile device, network signal strength it receives and quality-of-service (QoS) requirement of an application software submitted from that device. Scheduling such application software execution requests (from many mobile devices) on competent virtual machines to enhance user quality of experience (QoE) is a multi-constrained optimization problem. However, existing solutions in the literature either address utility maximization problem for service providers or optimize the application QoS levels, bypassing device-level and network-level contextual information. In this paper, a multi-objective nonlinear programming solution to the context-aware application software scheduling problem has been developed, namely, QoE and context-aware scheduling (QCASH) method, which minimizes the application execution times (i.e., maximizes the QoE) and maximizes the application execution success rate. To the best of our knowledge, QCASH is the first work in this domain that inscribes the optimal scheduling problem for mobile application software execution requests with three-dimensional context parameters. In QCASH, the context priority of each application is measured by applying min-max normalization and multiple linear regression models on three context parameters-battery level, network signal strength, and application QoS. Experimental results, found from simulation runs on CloudSim toolkit, demonstrate that the QCASH outperforms the state-of-the-art works well across the success rate, waiting time, and QoE. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
44. Universal power law behavior of the AC conductivity versus frequency of agglomerate morphologies in conductive carbon nanotube-reinforced epoxy networks.
- Author
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Greenhoe, Brian M., Hassan, Mohammad K., Wiggins, Jeffrey S., and Mauritz, Kenneth A.
- Subjects
- *
POWER law (Mathematics) , *CARBON nanotube testing , *EPOXY compounds , *MORPHOLOGY , *BROADBAND dielectric spectroscopy - Abstract
ABSTRACT The Jonscher universal power law for ac conductivity versus frequency ( f = ω/2π) in the dispersion region was tested for a multiwall carbon nanotube/epoxy nanocomposite. The effect of changes in agglomerate morphology on the fitting parameters A and n in the equation σac = Aωn was investigated. Changing nanotube agglomerate morphology was tracked by optical microscopy through curing. Evolving morphology was compared alongside ac conductivity obtained via a broadband dielectric spectrometer to elucidate possible physical meaning of the universal power law in the context of this system. The −log A/ n was unaffected by changes in agglomerate morphology affected during cure, yet connected with each other in their dependence on temperature. For this system, the relationship between the fitting parameters in the universal dynamic response equation remains empirical at this stage with regard to biphasic 'texture' or morphology within such a network. Electrical conductivity σ versus frequency ω for a composite consisting of agglomerated multiwalled carbon nanotubes dispersed throughout a cured epoxy matrix was discovered to follow the empirical universal dynamic response equation of Jonscher. The frequency behavior of the exponent n is discussed in terms of underlying morphology throughout which charge carriers migrate. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 1918-1923 [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
45. Electrical properties of FeII-terpyridine-Modified cellulose nanocrystals and polycaprolactone/FeII-CTP nanocomposites.
- Author
-
Hassan, Mohammad L., Fadel, Shaimaa M., Ward, Azza A., Moorefield, Charles M., and Newkome, George R.
- Subjects
- *
CELLULOSE nanocrystals , *POLYCAPROLACTONE , *TRANSMISSION electron microscopy , *ELECTRIC properties of nanocomposite materials , *ELECTRIC properties of carbon nanotubes - Abstract
Supramolecular crosslinked FeII-terpyridine cellulose nanocrystals (Fe-CTP) were prepared by surface modification of cellulose nanocrystals with 4′-chloro-2,2′:6′,2″-terpyridine and subsequent reaction with Fe(II)SO4. The prepared complex was characterized using transmission electron microscopy (TEM), ultraviolet spectroscopy (UV), thermogravimetric analysis (TGA), and measuring its electrical properties at temperatures from 25 to 70°C. Use of Fe-CTP at loadings from 1% to 10% (wt. ratio) in nanocomposites with polycaprolactone polymer was investigated; the nanocomposites were characterized regarding their electrical properties, which studied using broadband AC-relaxation spectroscopy in the frequency range between 0.1 Hz and 1 MHz. The results were compared to that of PCL nanocomposites containing multiwalled carbon nanotubes (CNT). Variation in real and imaginary parts of permittivity has been explained on the basis of interfacial polarization of fillers in the polymer medium. The percolation limit of the conductive CNT and Fe-CTP as studied by ac conductivity measurements has also been reported. Fe-CTP showed conductivity values in the range of semiconductors. PCL/Fe-CTP nanocomposites showed conductivity values from 1.98 × 10−11 to 3.76 × 10−6 while PCL/CNT nanocomposites showed conductivity values from 1.4 × 10−10 to 3.67 × 10−4 S/m for 1-10 wt% CNT content. POLYM. COMPOS., 37:2734-2743, 2016. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
46. Improvement in DRX Power Saving for Non-real-time Traffic in LTE.
- Author
-
Kawser, Mohammad Tawhid, Islam, Mohammad Rakibul, Islam, Khondoker Ziaul, Islam, Mohammad Atiqul, Hassan, Mohammad Mehadi, Ahmed, Zobayer, and Hasan, Rafid
- Subjects
LONG-Term Evolution (Telecommunications) ,ENERGY conservation ,STORAGE batteries ,DATA packeting ,STOCHASTIC analysis - Abstract
A discontinuous reception (DRX) operation is included in the Long Term Evolution (LTE) system to achieve power saving and prolonged battery life of the user equipment. An improvement in DRX power saving usually leads to a potential increase in the packet delay. An optimum DRX configuration depends on the current traffic, which is not easy to estimate accurately, particularly for non-real-time applications. In this paper, we propose a novel way to vary the DRX cycle length, avoiding a continuous estimation of the data traffic when only non-real-time applications are running with no active real-time applications. Because a small delay in non-realtime traffic does not essentially impact the user's experience adversely, we deliberately allow a limited amount of delay in our proposal to attain a significant improvement in power saving. Our proposal also improves the delay in service resumption after a long period of inactivity. We use a stochastic analysis assuming an M/G/1 queue to validate this improvement. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
47. Investigation of the physico-mechanical properties of electrospun PVDF/cellulose (nano)fibers.
- Author
-
Issa, Ahmed A., Al‐Maadeed, Mariam, Luyt, Adriaan S., Mrlik, Miroslav, and Hassan, Mohammad K.
- Subjects
POLYVINYLIDENE fluoride ,CRYSTALLINITY ,CELLULOSE fibers ,HYDROXYL group ,ELECTROSPINNING - Abstract
ABSTRACT The electro-activity and mechanical properties of PVDF depends mainly on the β-phase content and degree of crystallinity. In this study, cellulose fibers were used to improve these characteristics. This could be achieved because the hydroxyl groups on cellulose would force the fluorine atoms in PVDF to be in the trans-conformation, and the cellulose particles could act as nucleation centers. Electrospinning was used to prepare the PVDF/cellulose (nano)fibrous films, and this improved the total crystallinity and the formation of β-crystals. However, the presence and amount of cellulose in PVDF were found to have little influence on the β-phase content and on the total crystallinity of PVDF. Improvements in the extent of crystallinity and the β-phase content were primarily brought about by the chain- and crystal orientation as a result of electrospinning. The thermal stability of PVDF in the composites slightly increased with increasing cellulose content in the composites up to 1.0 wt %, while the modulus and tensile strength significantly increased up to the same filler level. The dielectric storage permittivity also increased with increasing cellulose content, but the presence of cellulose had no influence on the dynamics of the γ- and β-relaxations of the PVDF. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43594. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
48. Titanium With Nanotopography Induces Osteoblast Differentiation by Regulating Endogenous Bone Morphogenetic Protein Expression and Signaling Pathway.
- Author
-
M.S. Castro‐Raucci, Larissa, S. Francischini, Marcelo, N. Teixeira, Lucas, P. Ferraz, Emanuela, B. Lopes, Helena, T. de Oliveira, Paulo, Hassan, Mohammad Q., Rosa, Adalberto L., and Beloti, Marcio M.
- Published
- 2016
- Full Text
- View/download PDF
49. QoS and trust-aware coalition formation game in data-intensive cloud federations.
- Author
-
Hassan, Mohammad Mehedi, Abdullah‐Al‐Wadud, Mohammad, Almogren, Ahmad, Rahman, SK Md. Mizanur, Alelaiwi, Abdulhameed, Alamri, Atif, and Hamid, Md. Abdul
- Subjects
CLOUD computing ,SOFTWARE as a service ,COLLABORATIONISTS (Traitors) ,GAME theory ,DATA integrity - Abstract
This paper addresses the problem of efficient federation formation by the cloud providers (CPs) with an aim to fulfill the dynamic resource demands of users for supporting data-intensive workloads. Existing works only focus on forming federations based on the highest profit gained by each of the CPs in a federation. Therefore, these approaches often suffer from the risk of selecting unreliable CPs in the federation resulting in additional penalty cost and loss of CPs's reputation due to service level agreement violation between the users and the federation. In contrast, we argue that a trust model is necessary to find the most promising cloud collaborators. Accordingly, we propose a novel cloud federation formation mechanism by utilizing a trust-based cooperative game theory, which enables the CPs to dynamically form a federation based on profit maximization and penalty cost minimization as a result of selecting the trustworthy CPs. Simulation results show that the cloud federation formed by the proposed mechanism is stable, satisfies the fairness property, and yields higher profit for the participating CPs in the long run without incurring penalty cost as compared with the state-of-the-art approaches. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
50. A game-based incentive model for service cooperation in VANETs.
- Author
-
Mao, Yuxin, Zhu, Ping, Wei, Guiyi, Hassan, Mohammad Mehedi, and Hossain, M. Anwar
- Subjects
GAME theory ,VEHICULAR ad hoc networks ,WIRELESS sensor nodes ,COMPUTER users ,COMPUTER simulation - Abstract
Because of the highly dynamic topology and the unstable service status of nodes, services in vehicular ad hoc networks (VANETs) are not always reliable enough for users. Nodes in such a VANET incline to be selfish, which will even enhance this situation. In this work, we present an incentive model for VANETs to support more reliable services in network. We model the situation of service request and response in VANETs by using game theory. We consider the competitive and cooperative relationship between the nodes to formulate the game for VANETs. A contribution measurement is given in order to encourage cooperation during the game. Nodes are encouraged to provide more services to their neighbors in order to acquire more services from other nodes in our model. We also conduct a simulation for the proposed model and give detailed analysis in this work. From the results of the simulation, we argue that we could enable a VANET to support more reliable service by configuring suitable parameters for it. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
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