Browse publications by year: 2021

  1. Fulltext Molecular Dynamic Simulation Search for Possible Amphiphilic Drug Discovery for Covid-19
    Daood U, Gopinath D, Pichika MR, Mak KK, Seow LL
    Molecules, 2021 Apr 12;26(8).
    PMID: 33921378 DOI: 10.3390/molecules26082214
    To determine whether quaternary ammonium (k21) binds to Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2) spike protein via computational molecular docking simulations, the crystal structure of the SARS-CoV-2 spike receptor-binding domain complexed with ACE-2 (PDB ID: 6LZG) was downloaded from RCSB PD and prepared using Schrodinger 2019-4. The entry of SARS-CoV-2 inside humans is through lung tissues with a pH of 7.38-7.42. A two-dimensional structure of k-21 was drawn using the 2D-sketcher of Maestro 12.2 and trimmed of C18 alkyl chains from all four arms with the assumption that the core moiety k-21 was without C18. The immunogenic potential of k21/QA was conducted using the C-ImmSim server for a position-specific scoring matrix analyzing the human host immune system response. Therapeutic probability was shown using prediction models with negative and positive control drugs. Negative scores show that the binding of a quaternary ammonium compound with the spike protein's binding site is favorable. The drug molecule has a large Root Mean Square Deviation fluctuation due to the less complex geometry of the drug molecule, which is suggestive of a profound impact on the regular geometry of a viral protein. There is high concentration of Immunoglobulin M/Immunoglobulin G, which is concomitant of virus reduction. The proposed drug formulation based on quaternary ammonium to characterize affinity to the SARS-CoV-2 spike protein using simulation and computational immunological methods has shown promising findings.
    MeSH terms: Quaternary Ammonium Compounds/metabolism*; Quaternary Ammonium Compounds/chemistry; Binding Sites; Humans; Peptidyl-Dipeptidase A/metabolism; Peptidyl-Dipeptidase A/chemistry; Silanes/metabolism; Silanes/chemistry; Drug Discovery*; Molecular Docking Simulation; Spike Glycoprotein, Coronavirus/metabolism*; Spike Glycoprotein, Coronavirus/chemistry
  2. Fulltext Plant-Based Biosynthesis of Copper/Copper Oxide Nanoparticles: An Update on Their Applications in Biomedicine, Mechanisms, and Toxicity
    Letchumanan D, Sok SPM, Ibrahim S, Nagoor NH, Arshad NM
    Biomolecules, 2021 04 12;11(4).
    PMID: 33921379 DOI: 10.3390/biom11040564
    Plants are rich in phytoconstituent biomolecules that served as a good source of medicine. More recently, they have been employed in synthesizing metal/metal oxide nanoparticles (NPs) due to their capping and reducing properties. This green synthesis approach is environmentally friendly and allows the production of the desired NPs in different sizes and shapes by manipulating parameters during the synthesis process. The most commonly used metals and oxides are gold (Au), silver (Ag), and copper (Cu). Among these, Cu is a relatively low-cost metal that is more cost-effective than Au and Ag. In this review, we present an overview and current update of plant-mediated Cu/copper oxide (CuO) NPs, including their synthesis, medicinal applications, and mechanisms. Furthermore, the toxic effects of these NPs and their efficacy compared to commercial NPs are reviewed. This review provides an insight into the potential of developing plant-based Cu/CuO NPs as a therapeutic agent for various diseases in the future.
    MeSH terms: Biotechnology/methods*; Copper/chemistry*; Plants/metabolism*; Metal Nanoparticles/therapeutic use; Metal Nanoparticles/toxicity; Metal Nanoparticles/chemistry*; Green Chemistry Technology/methods; Phytochemicals/metabolism; Phytochemicals/chemistry
  3. Fulltext Improved Bacteriostatic and Anticorrosion Effects of Polycaprolactone/Chitosan Coated Magnesium via Incorporation of Zinc Oxide
    Bakhsheshi-Rad HR, Hamzah E, Ying WS, Razzaghi M, Sharif S, Ismail AF, et al.
    Materials (Basel), 2021 Apr 12;14(8).
    PMID: 33921460 DOI: 10.3390/ma14081930
    Magnesium has been recognized as a groundbreaking biodegradable biomaterial for implant applications, but its use is limited because it degrades too quickly in physiological solutions. This paper describes the research on the influence of polycaprolactone (PCL)/chitosan (CS)/zinc oxide (ZnO) composite coating (PCL/CS/ZnO) on the corrosion resistance and antibacterial activity of magnesium. The PCL/CS film presented a porous structure with thickness of about 40-50 μm, while after incorporation of ZnO into the PCL/CS, a homogenous film without pores and defects was attained. The ZnO embedded in PCL/CS enhanced corrosion resistance by preventing corrosive ions diffusion in the magnesium substrate. The corrosion, antibacterial, and cell interaction mechanism of the PCL/CS/ZnO composite coating is discussed in this study. In vitro cell culture revealed that the PCL/CS coating with low loaded ZnO significantly improved cytocompatibility, but coatings with high loaded ZnO were able to induce some cytotoxicity osteoblastic cells. It was also found that enhanced antibacterial activity of the PCL/CS/ZnO coating against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria, while less significant antibacterial activity was detected for uncoated Mg and PCL/CS coating. Based on the results, the PCL/CS coatings loaded with low ZnO content may be recommended as a candidate material for biodegradable Mg-based orthopedic implant applications.
    MeSH terms: Anti-Bacterial Agents; Biocompatible Materials; Caustics; Cell Communication; Corrosion; Escherichia coli; Ions; Magnesium; Minerals; Polyesters; Staphylococcus aureus; Zinc Oxide; Porosity; Cell Culture Techniques; Absorbable Implants; Chitosan
  4. Fulltext Bee Bread Ameliorates Vascular Inflammation and Impaired Vasorelaxation in Obesity-Induced Vascular Damage Rat Model: The Role of eNOS/NO/cGMP-Signaling Pathway
    Othman ZA, Zakaria Z, Suleiman JB, Nna VU, Che Romli A, Wan Ghazali WS, et al.
    Int J Mol Sci, 2021 Apr 19;22(8).
    PMID: 33921777 DOI: 10.3390/ijms22084225
    Obesity and hyperlipidemia are major risk factors for developing vascular diseases. Bee bread (BB) has been reported to exhibit some biological actions, including anti-obesity and anti-hyperlipidemic. This study aims to investigate whether bee bread can ameliorate vascular inflammation and impaired vasorelaxation activity through eNOS/NO/cGMP pathway in obese rats. Forty male Sprague-Dawley rats were randomly divided into four groups (n = 10/group), namely: control (normal group), obese rats (OB group), obese rats treated with bee bread (0.5 g/kg/day, OB/BB group) and obese rats treated with orlistat (10 mg/kg/day, OB/OR group). The latter three groups were given a high-fat diet (HFD) for 6 weeks to induced obesity before being administered with their respective treatments for another 6 weeks. After 12 weeks of the total experimental period, rats in the OB group demonstrated significantly higher Lee obesity index, lipid profile (total cholesterol, triglyceride, low-density lipoprotein), aortic proinflammatory markers (tumor necrosis factor-α, nuclear factor-κβ), aortic structural damage and impairment in vasorelaxation response to acetylcholine (ACh). Bee bread significantly ameliorated the obesity-induced vascular damage manifested by improvements in the lipid profile, aortic inflammatory markers, and the impaired vasorelaxation activity by significantly enhancing nitric oxide release, promoting endothelial nitric oxide synthase (eNOS) and cyclic guanosine monophosphate (cGMP) immunoexpression. These findings suggest that the administration of bee bread ameliorates the impaired vasorelaxation response to ACh by improving eNOS/NO/cGMP-signaling pathway in obese rats, suggesting its vascular therapeutic role.
    MeSH terms: Animals; Cyclic GMP/metabolism*; Hyperlipidemias/drug therapy; Hyperlipidemias/metabolism; Inflammation/drug therapy; Inflammation/metabolism; Male; Nitric Oxide/metabolism*; Nucleotides, Cyclic/metabolism*; Obesity/complications*; Propolis/therapeutic use*; Vasodilation/drug effects; Signal Transduction/drug effects; Rats, Sprague-Dawley; Rats; Nitric Oxide Synthase Type III/metabolism*; Diet, High-Fat/adverse effects
  5. Fulltext Sesame Oil-Based Nanostructured Lipid Carriers of Nicergoline, Intranasal Delivery System for Brain Targeting of Synergistic Cerebrovascular Protection
    Abourehab MAS, Khames A, Genedy S, Mostafa S, Khaleel MA, Omar MM, et al.
    Pharmaceutics, 2021 Apr 19;13(4).
    PMID: 33921796 DOI: 10.3390/pharmaceutics13040581
    Nicergoline (NIC) is a semisynthetic ergot alkaloid derivative applied for treatment of dementia and other cerebrovascular disorders. The efficacy of sesame oil to slow and reverse the symptoms of neurodegenerative cognitive disorders has been proven. This work aimed to formulate and optimize sesame oil-based NIC-nanostructured lipid carriers (NIC-NLCs) for intranasal (IN) delivery with expected synergistic and augmented neuroprotective properties. The NIC-NLC were prepared using sesame oil as a liquid lipid. A three-level, three-factor Box-Behnken design was applied to statistically optimize the effect of sesame oil (%) of the total lipid, surfactant concentration, and sonication time on particle size, zeta potential, and entrapment efficacy as responses. Solid-state characterization, release profile, and ex vivo nasal permeation in comparison to NIC solution (NIC-SOL) was studied. In vivo bioavailability from optimized NIC-NLC and NIC-SOL following IN and IV administration was evaluated and compared. The optimized NIC-NLC formula showed an average particle size of 111.18 nm, zeta potential of -15.4 mV, 95.11% entrapment efficacy (%), and 4.6% loading capacity. The NIC-NLC formula showed a biphasic, extended-release profile (72% after 48 h). Permeation of the NIC-NLC formula showed a 2.3 enhancement ratio. Bioavailability studies showed a 1.67 and 4.57 fold increase in plasma and brain following IN administration. The results also indicated efficient direct nose-to-brain targeting properties with the brain-targeting efficiency (BTE%) and direct transport percentage (DTP%) of 187.3% and 56.6%, respectively, after IN administration. Thus, sesame oil-based NIC-NLC can be considered as a promising IN delivery system for direct and efficient brain targeting with improved bioavailability and expected augmented neuroprotective action for the treatment of dementia.
    MeSH terms: Administration, Intranasal; Biological Availability; Brain; Cerebrovascular Disorders; Cognition; Dementia; Lipids; Nicergoline; Particle Size; Plasma; Sesame Oil; Sonication; Surface-Active Agents; Nanostructures
  6. Fulltext Sleep Quality and Physical Activity as Predictors of Mental Wellbeing Variance in Older Adults during COVID-19 Lockdown: ECLB COVID-19 International Online Survey
    Trabelsi K, Ammar A, Masmoudi L, Boukhris O, Chtourou H, Bouaziz B, et al.
    Int J Environ Res Public Health, 2021 Apr 19;18(8).
    PMID: 33921852 DOI: 10.3390/ijerph18084329
    BACKGROUND: The COVID-19 lockdown could engender disruption to lifestyle behaviors, thus impairing mental wellbeing in the general population. This study investigated whether sociodemographic variables, changes in physical activity, and sleep quality from pre- to during lockdown were predictors of change in mental wellbeing in quarantined older adults.

    METHODS: A 12-week international online survey was launched in 14 languages on 6 April 2020. Forty-one research institutions from Europe, Western-Asia, North-Africa, and the Americas, promoted the survey. The survey was presented in a differential format with questions related to responses "pre" and "during" the lockdown period. Participants responded to the Short Warwick-Edinburgh Mental Wellbeing Scale, the Pittsburgh Sleep Quality Index (PSQI) questionnaire, and the short form of the International Physical Activity Questionnaire.

    RESULTS: Replies from older adults (aged >55 years, n = 517), mainly from Europe (50.1%), Western-Asia (6.8%), America (30%), and North-Africa (9.3%) were analyzed. The COVID-19 lockdown led to significantly decreased mental wellbeing, sleep quality, and total physical activity energy expenditure levels (all p < 0.001). Regression analysis showed that the change in total PSQI score and total physical activity energy expenditure (F(2, 514) = 66.41 p < 0.001) were significant predictors of the decrease in mental wellbeing from pre- to during lockdown (p < 0.001, R2: 0.20).

    CONCLUSION: COVID-19 lockdown deleteriously affected physical activity and sleep patterns. Furthermore, change in the total PSQI score and total physical activity energy expenditure were significant predictors for the decrease in mental wellbeing.

    MeSH terms: Africa, Northern; Aged; Asia, Western; Communicable Disease Control; Europe; Humans; Surveys and Questionnaires; Sleep; Exercise
  7. Fulltext Arthropod Ectoparasites Have Potential to Bind SARS-CoV-2 via ACE
    Lam SD, Ashford P, Díaz-Sánchez S, Villar M, Gortázar C, de la Fuente J, et al.
    Viruses, 2021 04 19;13(4).
    PMID: 33921873 DOI: 10.3390/v13040708
    Coronavirus-like organisms have been previously identified in Arthropod ectoparasites (such as ticks and unfed cat flea). Yet, the question regarding the possible role of these arthropods as SARS-CoV-2 passive/biological transmission vectors is still poorly explored. In this study, we performed in silico structural and binding energy calculations to assess the risks associated with possible ectoparasite transmission. We found sufficient similarity between ectoparasite ACE and human ACE2 protein sequences to build good quality 3D-models of the SARS-CoV-2 Spike:ACE complex to assess the impacts of ectoparasite mutations on complex stability. For several species (e.g., water flea, deer tick, body louse), our analyses showed no significant destabilisation of the SARS-CoV-2 Spike:ACE complex, suggesting these species would bind the viral Spike protein. Our structural analyses also provide structural rationale for interactions between the viral Spike and the ectoparasite ACE proteins. Although we do not have experimental evidence of infection in these ectoparasites, the predicted stability of the complex suggests this is possible, raising concerns of a possible role in passive transmission of the virus to their human hosts.
    MeSH terms: Animals; Arthropods/classification; Arthropods/genetics; Arthropods/metabolism*; Arthropods/chemistry; Binding Sites; Ectoparasitic Infestations/parasitology; Humans; Peptidyl-Dipeptidase A/genetics; Peptidyl-Dipeptidase A/metabolism*; Peptidyl-Dipeptidase A/chemistry; Models, Molecular; Mutation; Phylogeny; Protein Binding; Sequence Homology; Arthropod Proteins/genetics; Arthropod Proteins/metabolism*; Arthropod Proteins/chemistry; Spike Glycoprotein, Coronavirus/genetics; Spike Glycoprotein, Coronavirus/metabolism; Spike Glycoprotein, Coronavirus/chemistry
  8. Fulltext Superhydrophobic Nanocoatings as Intervention against Biofilm-Associated Bacterial Infections
    Chan Y, Wu XH, Chieng BW, Ibrahim NA, Then YY
    Nanomaterials (Basel), 2021 Apr 19;11(4).
    PMID: 33921904 DOI: 10.3390/nano11041046
    Biofilm formation represents a significant cause of concern as it has been associated with increased morbidity and mortality, thereby imposing a huge burden on public healthcare system throughout the world. As biofilms are usually resistant to various conventional antimicrobial interventions, they may result in severe and persistent infections, which necessitates the development of novel therapeutic strategies to combat biofilm-based infections. Physicochemical modification of the biomaterials utilized in medical devices to mitigate initial microbial attachment has been proposed as a promising strategy in combating polymicrobial infections, as the adhesion of microorganisms is typically the first step for the formation of biofilms. For instance, superhydrophobic surfaces have been shown to possess substantial anti-biofilm properties attributed to the presence of nanostructures. In this article, we provide an insight into the mechanisms underlying biofilm formation and their composition, as well as the applications of nanomaterials as superhydrophobic nanocoatings for the development of novel anti-biofilm therapies.
  9. Fulltext Evaluation of the Diagnostic Accuracy of a New Biosensors-Based Rapid Diagnostic Test for the Point-Of-Care Diagnosis of Previous and Recent Dengue Infections in Malaysia
    Chong ZL, Soe HJ, Ismail AA, Mahboob T, Chandramathi S, Sekaran SD
    Biosensors (Basel), 2021 Apr 22;11(5).
    PMID: 33921935 DOI: 10.3390/bios11050129
    Dengue is a major threat to public health globally. While point-of-care diagnosis of acute/recent dengue is available to reduce its mortality, a lack of rapid and accurate testing for the detection of previous dengue remains a hurdle in expanding dengue seroepidemiological surveys to inform its prevention, especially vaccination, to reduce dengue morbidity. This study evaluated ViroTrack Dengue Serostate, a biosensors-based semi-quantitative anti-dengue IgG (immunoglobulin G) immuno-magnetic agglutination assay for the diagnosis of previous and recent dengue in a single test. Blood samples were obtained from 484 healthy participants recruited randomly from two communities in Petaling district, Selangor, Malaysia. The reference tests were Panbio Dengue IgG indirect and capture enzyme-linked immunosorbent assays, in-house hemagglutination inhibition assay, and focus reduction neutralization test. Dengue Serostate had a sensitivity and specificity of 91.1% (95%CI 87.8-93.8) and 91.1% (95%CI 83.8-95.8) for the diagnosis of previous dengue, and 90.2% (95%CI 76.9-97.3) and 93.2% (95%CI 90.5-95.4) for the diagnosis of recent dengue, respectively. Its positive predictive value of 97.5% (95%CI 95.3-98.8) would prevent most dengue-naïve individuals from being vaccinated. ViroTrack Dengue Serostate's good point-of-care diagnostic accuracy can ease the conduct of dengue serosurveys to inform dengue vaccination strategy and facilitate pre-vaccination screening to ensure safety.
    MeSH terms: Point-of-Care Testing*; Adult; Antibodies, Viral/blood; Dengue/blood; Dengue/diagnosis*; Diagnostic Tests, Routine; Enzyme-Linked Immunosorbent Assay; Female; Humans; Immunoglobulin G; Malaysia; Sensitivity and Specificity; Biosensing Techniques*; Point-of-Care Systems; Young Adult
  10. Fulltext Baicalein and Baicalin Inhibit SARS-CoV-2 RNA-Dependent-RNA Polymerase
    Zandi K, Musall K, Oo A, Cao D, Liang B, Hassandarvish P, et al.
    Microorganisms, 2021 Apr 22;9(5).
    PMID: 33921971 DOI: 10.3390/microorganisms9050893
    Coronavirus Disease 2019 (COVID-19) is a deadly emerging infectious disease caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Because SARS-CoV-2 is easily transmitted through the air and has a relatively long incubation time, COVID-19 has rapidly developed into a global pandemic. As there are no antiviral agents for the prevention and treatment of this severe pathogen except for remdesivir, development of antiviral therapies to treat infected individuals remains highly urgent. Here, we showed that baicalein and baicalin exhibited significant antiviral activity against SARS-CoV-2, the causative agent of COVID-19 through in vitro studies. Our data through cell-based and biochemical studies showed that both compounds act as SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) inhibitors directly and inhibit the activity of the SARS-CoV-2 RdRp, but baicalein was more potent. We also showed specific binding of baicalein to the SARS-CoV-2 RdRp, making it a potential candidate for further studies towards therapeutic development for COVID-19 as a selective non-nucleoside polymerase inhibitor.
  11. Fulltext Redesigning a Healthcare Demand Questionnaire for National Population Survey: Experience of a Developing Country
    Chong DWQ, Jawahir S, Tan EH, Sararaks S
    Int J Environ Res Public Health, 2021 04 22;18(9).
    PMID: 33921985 DOI: 10.3390/ijerph18094435
    Since its inception in 1986, the contents of the National Health and Morbidity Survey (NHMS) have been periodically updated to support emerging health data needs for evidence-based policy and program development. In 2018, the healthcare demand questionnaire was redesigned to capture diverse and changing population demand for healthcare services and their utilization pattern. This paper describes the methods and processes undertaken in redesigning the questionnaire. We aim to highlight the systematic and inclusive approach, enabling all potential evidence users to be involved, indirectly encouraging research evidence uptake for policy and program planning. We applied a systematic approach of comprehensive literature search for national-level population survey instruments implemented globally and translated non-English tools to English. The development phases were iterative, conducted in parallel with active stakeholder engagements. Here, we detailed the processes in the planning and exploratory phase as well as a qualitative assessment of the questionnaire. We included instruments from 45 countries. The majority were from the Organisation for Economic Co-operation and Development (OECD) countries and focused on perceived health, health-related behavior, and healthcare use. Thirty-four stakeholders from 14 areas of expertise were involved. Stakeholders identified additional content areas required, such as chronic pain, alternative use of healthcare services (community pharmacy, home-visit, and private medical laboratory), family doctor, and informal caregiving. The questionnaire, redesigned based on existing literature with concordant involvement and iterative feedback from stakeholders, improved the choice of health topics through the identification of new topics and modification of existing questions to better meet future evidence needs on health problems, strategy, and program planning towards strengthening the nation's health systems.
    MeSH terms: Delivery of Health Care*; Developing Countries*; Surveys and Questionnaires; Program Development
  12. Fulltext Surface-Mounted Bare and Packaged Fiber Bragg Grating Sensors for Measuring Rock Strain in Uniaxial Testing
    Isah BW, Mohamad H
    Sensors (Basel), 2021 Apr 22;21(9).
    PMID: 33922008 DOI: 10.3390/s21092926
    The paper explores the possibility of using high-resolution fiber Bragg grating (FBG) sensing technology for on-specimen strain measurement in the laboratory. The approach provides a means to assess the surface deformation of the specimen, both the axial and radial, through a chain of FBG sensor (C-FBG), in a basic setup of a uniaxial compression test. The method is cost-effective, straightforward and can be commercialized. Two C-FBG; one was applied directly to the sample (FBGBare), and the other was packaged (FBGPack) for ease of application. The approach measures the local strain with high-resolution and accuracy levels that match up to the existing local strain measuring sensors. The approach enables the evaluation of small-strain properties of the specimen intelligently. The finite element model analysis deployed has proven the adaptability of the technique for measuring material deformation. The adhesive thickness and packaging technique have been shown to influence the sensitivity of the FBG sensors. Owing to the relative ease and low-cost of instrumentation, the suggested method has a great potential to be routinely applied for elemental testing in the laboratory.
    MeSH terms: Adhesives; Cost-Benefit Analysis; Dietary Fiber; Fiber Optic Technology; Laboratories; Technology; Product Packaging; Finite Element Analysis; Optical Fibers
  13. Fulltext Bibliometric Analysis of Hydrocarbon Bioremediation in Cold Regions and a Review on Enhanced Soil Bioremediation
    Yap HS, Zakaria NN, Zulkharnain A, Sabri S, Gomez-Fuentes C, Ahmad SA
    Biology (Basel), 2021 Apr 22;10(5).
    PMID: 33922046 DOI: 10.3390/biology10050354
    The increased usage of petroleum oils in cold regions has led to widespread oil pollutants in soils. The harsh environmental conditions in cold environments allow the persistence of these oil pollutants in soils for more than 20 years, raising adverse threats to the ecosystem. Microbial bioremediation was proposed and employed as a cost-effective tool to remediate petroleum hydrocarbons present in soils without significantly posing harmful side effects. However, the conventional hydrocarbon bioremediation requires a longer time to achieve the clean-up standard due to various environmental factors in cold regions. Recent biotechnological improvements using biostimulation and/or bioaugmentation strategies are reported and implemented to enhance the hydrocarbon removal efficiency under cold conditions. Thus, this review focuses on the enhanced bioremediation for hydrocarbon-polluted soils in cold regions, highlighting in situ and ex situ approaches and few potential enhancements via the exploitation of molecular and microbial technology in response to the cold condition. The bibliometric analysis of the hydrocarbon bioremediation research in cold regions is also presented.
  14. Fulltext Design and Evaluation of a Flexible Dual-Band Meander Line Monopole Antenna for On- and Off-Body Healthcare Applications
    Ali SM, Sovuthy C, Noghanian S, Ali Z, Abbasi QH, Imran MA, et al.
    Micromachines (Basel), 2021 Apr 22;12(5).
    PMID: 33922053 DOI: 10.3390/mi12050475
    The human body is an extremely challenging environment for wearable antennas due to the complex antenna-body coupling effects. In this article, a compact flexible dual-band planar meander line monopole antenna (MMA) with a truncated ground plane made of multiple layers of standard off-the-shelf materials is evaluated to validate its performance when worn by different subjects to help the designers who are shaping future complex on-/off-body wireless devices. The antenna was fabricated, and the measured results agreed well with those from the simulations. As a reference, in free-space, the antenna provided omnidirectional radiation patterns (ORP), with a wide impedance bandwidth of 1282.4 (450.5) MHz with a maximum gain of 3.03 dBi (4.85 dBi) in the lower (upper) bands. The impedance bandwidth could reach up to 688.9 MHz (500.9 MHz) and 1261.7 MHz (524.2 MHz) with the gain of 3.80 dBi (4.67 dBi) and 3.00 dBi (4.55 dBi), respectively, on the human chest and arm. The stability in results shows that this flexible antenna is sufficiently robust against the variations introduced by the human body. A maximum measured shift of 0.5 and 100 MHz in the wide impedance matching and resonance frequency was observed in both bands, respectively, while an optimal gap between the antenna and human body was maintained. This stability of the working frequency provides robustness against various conditions including bending, movement, and relatively large fabrication tolerances.
  15. Fulltext Production of Biodegradable Polymer from Agro-Wastes in Alcaligenes sp. and Pseudomonas sp
    Sayyed RZ, Shaikh SS, Wani SJ, Rehman MT, Al Ajmi MF, Haque S, et al.
    Molecules, 2021 Apr 22;26(9).
    PMID: 33922162 DOI: 10.3390/molecules26092443
    The present study was aimed to evaluate the suitability of agro-wastes and crude vegetable oils for the cost-effective production of poly-β-hydroxybutyrate (PHB), to evaluate growth kinetics and PHB production in Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1 with these carbon substrates and to study the biodegradation of PHB accumulated by these cultures. Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1 accumulates higher amounts of PHB corn (79.90% of dry cell mass) and rice straw (66.22% of dry cell mass) medium respectively. The kinetic model suggests that the Pseudomonas sp. RZS1 follows the Monod model more closely than A. faecalis RZS4. Both the cultures degrade their PHB extract under the influence of PHB depolymerase. Corn waste and rice straw appear as the best and cost-effective substrates for the sustainable production of PHB from Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1. The biopolymer accumulated by these organisms is biodegradable in nature. The agro-wastes and crude vegetable oils are good and low-cost sources of nutrients for the growth and production of PHB and other metabolites. Their use would lower the production cost of PHB and the low-cost production will reduce the sailing price of PHB-based products. This would promote the large-scale commercialization and popularization of PHB as an ecofriendly bioplastic/biopolymer.
    MeSH terms: Agriculture*; Alcaligenes/metabolism*; Biodegradation, Environmental; Biopolymers/biosynthesis*; Biopolymers/isolation & purification; Biopolymers/chemistry; Fermentation*; Kinetics; Plastics/chemistry; Pseudomonas/metabolism*; Spectrum Analysis; Waste Products*; Biomass
  16. Fulltext Development of the Active Ageing Awareness Questionnaire in Malaysia
    Ahmad Bahuri NH, Rizal H, Abdul Majid H, Said MA, Su TT
    Healthcare (Basel), 2021 Apr 22;9(5).
    PMID: 33922206 DOI: 10.3390/healthcare9050499
    The world's ageing population is associated with increased morbidity, disability, and social and financial insecurity, which may affect quality of life (QoL). Therefore, the World Health Organization (WHO) endorsed the Active Ageing Framework (AAF) in 2002 to enhance QoL as people age. However, little is known about the status of awareness of active ageing among the population, and there is no appropriate tool for assessment. Hence, the Awareness of Active Ageing Questionnaire (AAAQ) was developed. The content, linguistic and face validations together with test-retest reliability were conducted. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were performed to test the structural validity of the AAAQ. A total of 110 participants (mean ± SD = 50.19 ± 5.52) were selected for the pilot, 81 participants (mean ± SD = 49.40 ± 5.70) for the test-retest, and 404 participants (mean ± SD = 49.90 ± 5.80) for CFA and EFA tests. The 16-item AAAQ Malay version showed satisfactory reliability and validity. The Cronbach's alpha was more than 0.7 and showed good fit: Cmin/df = 2.771, GFI = 0.903, TLI = 0.951, RMSEA = 0.08. The AAAQ is suitable for measuring the awareness of active ageing among the middle-aged population in Malaysia.
  17. Fulltext A Heuristic Approach for Optical Transceiver Placement to Optimize SNR and Illuminance Uniformities of an Optical Body Area Network
    Masroor K, Jeoti V, Drieberg M, Cheab S, Rajbhandari S
    Sensors (Basel), 2021 Apr 22;21(9).
    PMID: 33922288 DOI: 10.3390/s21092943
    The bi-directional information transfer in optical body area networks (OBANs) is crucial at all the three tiers of communication, i.e., intra-, inter-, and beyond-BAN communication, which correspond to tier-I, tier-II, and tier-III, respectively. However, the provision of uninterrupted uplink (UL) and downlink (DL) connections at tier II (inter-BAN) are extremely critical, since these links serve as a bridge between tier-I (intra-BAN) and tier-III (beyond-BAN) communication. Any negligence at this level could be life-threatening; therefore, enabling quality-of-service (QoS) remains a fundamental design issue at tier-II. Consequently, to provide QoS, a key parameter is to ensure link reliability and communication quality by maintaining a nearly uniform signal-to-noise ratio (SNR) within the coverage area. Several studies have reported the effects of transceiver related parameters on OBAN link performance, nevertheless the implications of changing transmitter locations on the SNR uniformity and communication quality have not been addressed. In this work, we undertake a DL scenario and analyze how the placement of light-emitting diode (LED) lamps can improve the SNR uniformity, regardless of the receiver position. Subsequently, we show that using the principle of reciprocity (POR) and with transmitter-receiver positions switched, the analysis is also applicable to UL, provided that the optical channel remains linear. Moreover, we propose a generalized optimal placement scheme along with a heuristic design formula to achieve uniform SNR and illuminance for DL using a fixed number of transmitters and compare it with an existing technique. The study reveals that the proposed placement technique reduces the fluctuations in SNR by 54% and improves the illuminance uniformity up to 102% as compared to the traditional approach. Finally, we show that, for very low luminous intensity, the SNR values remain sufficient to maintain a minimum bit error rate (BER) of 10-9 with on-off keying non-return-to-zero (OOK-NRZ) modulation format.
    MeSH terms: Heuristics; Communication; Light; Maintenance; Malpractice; Reproducibility of Results; Signal-To-Noise Ratio
  18. Fulltext Glyphosate Herbicide Induces Changes in the Growth Pattern and Somatic Indices of Crossbred Red Tilapia (O. niloticus × O. mossambicus)
    Muhammad UA, Yasid NA, Daud HM, Shukor MY
    Animals (Basel), 2021 Apr 22;11(5).
    PMID: 33922293 DOI: 10.3390/ani11051209
    The development of glyphosate-resistant genetically modified organisms (GMO) has increased the use of herbicide glyphosate by several magnitudes in recent years. It is now the most commonly used pesticide globally that affects aquatic habitats, especially fish. This study aims to add new knowledge on the effect of technical grade glyphosate on several toxicity parameters and to identify the most effective parameter in predicting technical grade glyphosate chronic toxicity (seven weeks) to fish, especially Malaysia's heavily farmed red tilapia. The results show that a relatively high concentration of technical grade glyphosate is needed to induce significant changes in all tested parameters. However, the results also indicate that the bodyweight index is the most sensitive toxicity parameter in that a reduction in body weight was observed at 25 mg/L of glyphosate. Negative correlations between the glyphosate concentration and toxicity parameters such as specific growth rate (SGR), hepato-somatic index (HIS), and gonado-somatic index (GSI) were observed. The fish condition factor and feed conversion ratio were found not to be affected at the highest glyphosate concentration tested (150 mg/L). To conclude, crossbred red tilapia (O. niloticus × O. mossambicus) is one potential species for evaluating the toxic effects of technical grade glyphosate on fish.
    MeSH terms: Animals; Body Weight; Glycine; Herbicides; Malaysia; Pesticides; Tilapia; Ecosystem; Organisms, Genetically Modified; Organophosphate Poisoning
  19. Fulltext Time-Use and Mental Health in Older Adults: A Scoping Review
    Foong HF, Lim SY, Koris R, Haron SA
    Int J Environ Res Public Health, 2021 Apr 22;18(9).
    PMID: 33922295 DOI: 10.3390/ijerph18094459
    Time-use of older adults can be different than in earlier life, especially during the transition from pre- to post-retirement or after experiencing major life events, and the changes could affect their mental health. However, the extent and nature of such research in gerontology have not been examined to date. Therefore, this scoping review sought to map the literature on time-use and mental health in the older population to examine the extent and nature of those research activities. A scoping review was conducted using four databases-PubMed, Scopus, CINAHL, and EMBASE according to PRISMA guidelines. Data were extracted using a pretested tool to develop a descriptive analysis and thematic summary. A total of 11 articles met the eligibility criteria. Seven out of 11 studies involved cross-sectional design, while the remainder were longitudinal studies. The longitudinal studies mainly were secondary data analysis. Time-use data were mainly collected using daily diaries, and the most common mental health outcome included was depression. Only two studies did not evaluate the direct relationship between time-use and mental health. Our review has revealed studies evaluating time-use and mental health in older adults. Limitations of review and recommendations for future studies are discussed.
    MeSH terms: Aged; Cross-Sectional Studies; Humans; Mental Health*; Population Groups*
  20. Fulltext Thermostable Heptaplex PCR Assay for the Detection of Six Respiratory Bacterial Pathogens
    Nik Zuraina NMN, Goni MD, Amalina KN, Hasan H, Mohamad S, Suraiya S
    Diagnostics (Basel), 2021 Apr 22;11(5).
    PMID: 33922299 DOI: 10.3390/diagnostics11050753
    A thermostabilized, multiplex polymerase chain reaction (mPCR) assay was developed in this study for the detection of six respiratory bacterial pathogens. Specific primers were designed for an internal amplification control (IAC) and six target sequences from Klebsiella pneumoniae, Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa, Mycobacterium tuberculosis, and Haemophilus influenzae. The resultant seven-band positive amplification control (PAC) of this heptaplex PCR assay corresponded to 105 base pairs (bp) of IAC, 202 bp of K. pneumoniae, 293 bp of S. aureus, 349 bp of S. pneumoniae, 444 bp of P. aeruginosa, 505 bp of M. tuberculosis, and 582 bp of H. influenzae. Results found that 6% (w/v) of the stabilizer was optimum to preserve the functional conformation of Taq DNA polymerase enzyme. This assay was stable at ambient temperature for at least 6 months. The sensitivity and specificity of this assay were both 100% when testing on the intended target organisms (n = 119) and non-intended species (n = 57). The mPCR assay developed in this study enabled accurate, rapid, and simple detection of six respiratory bacteria.
    MeSH terms: Haemophilus influenzae; Klebsiella pneumoniae; Mycobacterium tuberculosis; Pseudomonas aeruginosa; Sensitivity and Specificity; Staphylococcal Infections; Staphylococcus aureus; Streptococcus pneumoniae; Temperature; Tuberculosis; DNA Primers; Taq Polymerase; Base Pairing; Methicillin-Resistant Staphylococcus aureus; Multiplex Polymerase Chain Reaction
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