Displaying publications 1 - 20 of 65 in total

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  1. Fulltext Vegetation-edaphic correlation and importance value index in himalayan 'ecotone' temperate conifer forest using the multivariate technique
    Ali F, Zeb M, Amin M, Rajpar MN, Hidayat S, Khan WR
    Saudi J Biol Sci, 2024 May;31(5):103983.
    PMID: 38590389 DOI: 10.1016/j.sjbs.2024.103983
    Himalayan 'Ecotone' temperate conifer forest is the cradle of life for human survival and wildlife existence. In spite of the importance of these areas, they have not been studied in depth. This study aimed to quantify the floristic structure, important value index (IVI), topographic and edaphic variables between 2019 and 2020 utilizing circular quadrant method (10 m x 10 m). The upper-storey layer consisted of 17 tree species belongs to 12 families and 9 orders. Middle-storey shrubs comprised of 23 species representing 14 families and 12 orders. A total of 43 species of herbs, grasses, and ferns were identified from the ground-storey layer, representing 25 families and 21 orders. Upper-storey vegetation structure was dominated by Pinus roxburghii (22.45 %) and middle-storey by Dodonaea viscosa (7.69 %). However, the ground layer vegetation was diverse in species composition (43 species) and distribution. The floral vegetation structure was encompassing of three floral communities which were diverse in IVI, such as, in Piro-Aial (Group 2), Pinus roxburghii (54.46 x 15.94) had the highest IVI value, followed by Pinus wallichiana (45.21 x 14.85) in Piwa-Quin (Group 3) and Ailanthus altissima (22.84 x 19.25) in Aial-Qugal (Group 1). However, the IVI values for Aesculus indica, Celtis australis, and Quercus incana in Aial-Qugal (Group 1) were not determined due to low detection rate. Nevertheless, eleven of these species showed 0 IVI values in Piro-Aial (Group 2) and Piwa-Quin (Group 3). CCA ordination biplot illustrated the significant differences among floral communities and its distribution, which impacted by temperature, rainfall, soil pH, altitude, and topographic features. Ward's agglomerative clustering finding reflected 'Ecotone' temperate conifer forest is rich and diverse floristic structure.
  2. Fulltext Galactoside-Based Molecule Enhanced Antimicrobial Activity through Acyl Moiety Incorporation: Synthesis and In Silico Exploration for Therapeutic Target
    Ahmmed F, Al-Mijalli SH, Abdallah EM, Eissa IH, Ali F, Bhat AR, et al.
    Pharmaceuticals (Basel), 2023 Jul 13;16(7).
    PMID: 37513910 DOI: 10.3390/ph16070998
    In this study, a series of galactoside-based molecules, compounds of methyl β-d-galactopyranoside (MDGP, 1), were selectively acylated using 2-bromobenzoyl chloride to obtain 6-O-(2-bromobenzoyl) substitution products, which were then transformed into 2,3,4-tri-O-6-(2-bromobenzoyl) compounds (2-7) with various nontraditional acyl substituents. The chemical structures of the synthesized analogs were characterized by spectroscopic methods and physicochemical and elemental data analyses. The antimicrobial activities of the compounds against five human pathogenic bacteria and two phyto-fungi were evaluated in vitro and it was found that the acyl moiety-induced synthesized analogs exhibited varying levels of antibacterial activity against different bacteria, with compounds 3 and 6 exhibiting broad-spectrum activity and compounds 2 and 5 exhibiting activity against specific bacteria. Compounds 3 and 6 were tested for MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration) based on their activity. The synthesized analogs were also found to have potential as a source of new antibacterial agents, particularly against gram-positive bacteria. The antifungal results suggested that the synthesized analogs could be a potential source of novel antifungal agents. Moreover, cytotoxicity testing revealed that the compounds are less toxic. A structure-activity relationship (SAR) investigation revealed that the lauroyl chain [CH3(CH2)10CO-] and the halo-aromatic chain [3(/4)-Cl.C6H4CO-] in combination with sugar, had the most potent activity against bacterial and fungal pathogens. Density functional theory (DFT)-calculated thermodynamic and physicochemical parameters, and molecular docking, showed that the synthesized molecule may block dengue virus 1 NS2B/NS3 protease (3L6P). A 150 ns molecular dynamic simulation indicated stable conformation and binding patterns in a stimulating environment. In silico ADMET calculations suggested that the designed (MDGP, 1) had good drug-likeness values. In summary, the newly synthesized MDGP analogs exhibit potential antiviral activity and could serve as a therapeutic target for dengue virus 1 NS2B/NS3 protease.
  3. Fulltext Irreversibility analysis of radiative flow of Prandtl nanofluid over a stretched surface in Darcy-Forchheimer medium with activation energy and chemical reaction
    Zafar SS, Khan U, Ali F, Eldin SM, Saeed AM, Zaib A, et al.
    Heliyon, 2023 Apr;9(4):e14877.
    PMID: 37025881 DOI: 10.1016/j.heliyon.2023.e14877
    This communication elaborates the irreversibility analysis of the flow of Prandtl nanofluid along with thermal radiation past a permeable stretched surface embedded in a Darcy-Forchheimer medium. The activation and chemical impressions along with effects of thermophoretic and Brownian motion are as well examined. The flow symmetry of the problem is modeled mathematically and leading equations are rehabilitated into nonlinear ordinary differential equations (ODEs) through the assistance of suitable similarity variables. The Keller-box technique in MATLAB is employed to draw the impacts of the contributing elements on the velocity field, temperature distribution, and concentration. The impact of the Prandtl fluid parameter has mounting performance for the velocity whereas conflicting behavior is examined in the temperature profile. The achieved numerical results are matched correspondingly with the present symmetrical solutions in restrictive cases and fantastic agreement is scrutinized. In addition, the entropy generation uplifts for the growing values of the Prandtl fluid parameter, thermal radiation, and Brinkman number and decreases for growing numbers of the inertia coefficient parameter. It is also discovered that the coefficient of friction decreases for all parameters involved in the momentum equation. Features of nanofluids can be found in a variety of real-world fields, including microfluidics, industry, transportation, the military, and medicine.
  4. Signatures of purifying selection and site-specific positive selection on the mitochondrial DNA of dromedary camels (Camelus dromedarius)
    Bahbahani H, Al-Zoubi S, Ali F, Afana A, Dashti M, Al-Ateeqi A, et al.
    Mitochondrion, 2023 Mar;69:36-42.
    PMID: 36690316 DOI: 10.1016/j.mito.2023.01.004
    The two species of the Old World Camelini tribe, dromedary and Bactrian camels, show superior adaptability to the different environmental conditions they populate, e.g. desert, mountains and coastal areas, which might be associated with adaptive variations on their mitochondrial DNA. Here, we investigate signatures of natural selection in the 13-mitochondrial protein-coding genes of different dromedary camel populations from the Arabian Peninsula, Africa and southwest Asia. The full mitogenome sequences of 42 dromedaries, 38 domestic Bactrian, 29 wild Bactrian camels and 31 samples representing the New World Lamini tribe reveal species-wise genetic distinction among Camelidae family species, with no evidence of geographic distinction among dromedary camels. We observe gene-wide signals of adaptive divergence between the Old World and New World camels, with evidence of purifying selection among Old World camel species. Upon comparing the different Camelidae tribes, 27 amino acid substitutions across ten mtDNA protein-coding genes were found to be under positive selection, in which, 24 codons were defined to be under positive adaptive divergence between Old World and New World camels. Seven codons belonging to three genes demonstrated positive selection in dromedary lineage. A total of 89 codons were found to be under positive selection in Camelidae family based on investigating the impact of amino acid replacement on the physiochemical properties of proteins, including equilibrium constant and surrounding hydrophobicity. These mtDNA variants under positive selection in the Camelidae family might be associated with their adaptation to their contrasting environments.
  5. Fulltext A Bibliometric Analysis of the Journal of Religion and Health: Sixty Years of Publication (1961-2021)
    Carey LB, Kumar S, Goyal K, Ali F
    J Relig Health, 2023 Feb;62(1):8-38.
    PMID: 36622579 DOI: 10.1007/s10943-022-01704-4
    In 1961, the Journal of Religion and Health (JORH) commenced publishing articles that examined modern religious and spiritual philosophy in relation to psychology and health. The year 2021 marked the 60th anniversary of the founding of JORH. This research paper retrospectively analyses the journal's content. It provides insight into JORH's publication trends, citation records, prominent themes, authors' collaboration and its aggregate contribution to the field of religion and health. Over time, the number of publications, citations and downloads of JORH articles have substantially increased, as has the journals prominence and diverse contributions to the study of religion, spirituality and health.
  6. Fulltext Doxycycline's Potential Role in Reducing Thrombosis and Mortality in Critically Ill Patients With COVID-19: A Multicenter Cohort Study
    Al Sulaiman K, Aljuhani O, Korayem GB, Alnajjar LI, Altebainawi AF, AlFaifi M, et al.
    Clin Appl Thromb Hemost, 2023;29:10760296231177017.
    PMID: 37322869 DOI: 10.1177/10760296231177017
    Doxycycline has revealed potential effects in animal studies to prevent thrombosis and reduce mortality. However, less is known about its antithrombotic role in patients with COVID-19. Our study aimed to evaluate doxycycline's impact on clinical outcomes in critically ill patients with COVID-19. A multicenter retrospective cohort study was conducted between March 1, 2020, and July 31, 2021. Patients who received doxycycline in intensive care units (ICUs) were compared to patients who did not (control). The primary outcome was the composite thrombotic events. The secondary outcomes were 30-day and in-hospital mortality, length of stay, ventilator-free days, and complications during ICU stay. Propensity score (PS) matching was used based on the selected criteria. Logistic, negative binomial, and Cox proportional hazards regression analyses were used as appropriate. After PS (1:3) matching, 664 patients (doxycycline n = 166, control n = 498) were included. The number of thromboembolic events was lower in the doxycycline group (OR: 0.54; 95% CI: 0.26-1.08; P = .08); however, it failed to reach to a statistical significance. Moreover, D-dimer levels and 30-day mortality were lower in the doxycycline group (beta coefficient [95% CI]: -0.22 [-0.46, 0.03; P = .08]; HR: 0.73; 95% CI: 0.52-1.00; P = .05, respectively). In addition, patients who received doxycycline had significantly lower odds of bacterial/fungal pneumonia (OR: 0.65; 95% CI: 0.44-0.94; P = .02). The use of doxycycline as adjunctive therapy in critically ill patients with COVID-19 might may be a desirable therapeutic option for thrombosis reduction and survival benefits.
  7. Fulltext Psychology in action: Social media communication, CSR, and consumer behavior management in banking
    Liu Y, Naveed RT, Kanwal S, Tahir Khan M, Dalain AF, Lan W
    PLoS One, 2023;18(8):e0289281.
    PMID: 37590276 DOI: 10.1371/journal.pone.0289281
    In today's digitally interconnected world, social media emerges as a powerful tool, offering different opportunities for modern businesses. Not only do organizations use social media for marketing purposes, but they also endeavor to influence consumer psychology and behavior. Although prior studies indicate social media's efficacy in disseminating corporate social responsibility (CSR) communications, there remains a dearth of research addressing the impact of CSR-related messaging from banks on consumers' brand advocacy behavior (CBAB). Our study seeks to bridge this gap, exploring the CSR-CBAB relationship within the banking sector of an emerging economy. Additionally, we investigate the roles of consumers' emotions and values in mediating and moderating their CBAB, introducing two mediating factors, consumer happiness (HP) and admiration (BRAD), and moderating variable altruistic values (ATVL). Data collection involved an adapted questionnaire targeting banking consumers. The structural analysis revealed a positive correlation between a bank's CSR-related social media communications and CBAB. HP and BRAD were identified as mediators in this relationship, while ATVL emerged as a moderator. These findings hold significant theoretical and practical implications. For instance, our research highlights the indispensable role of social media in effectively conveying CSR-related information to banking consumers, subsequently enhancing their advocacy intentions.
  8. Experiences and perceptions of COVID-19 infection and vaccination among Palestinian refugees in Jerash camp and Jordanian citizens: a comparative cross-sectional study by face-to-face interviews
    Al-Hatamleh MAI, Hatmal MM, Mustafa SHF, Alzu'bi M, AlSou'b AF, Abughanam SNS, et al.
    Infect Dis Poverty, 2022 Dec 13;11(1):123.
    PMID: 36510264 DOI: 10.1186/s40249-022-01047-y
    BACKGROUND: During the COVID-19 vaccination, the access to vaccines has been unequal among countries and individuals, for example low-income countries displayed significant low levels of vaccination. Furthermore, most refugees are living in developing low-income countries which struggling to access the essential health-care services including vaccination. Thus, the objective of this study was to assess the experiences and perceptions of COVID-19 infection and vaccination among Palestine refugees in Jerash camp compared to resident Jordanian citizens.

    METHODS: A face-to-face interview-based comparative cross-sectional study was carried out among Palestine refugees in Jerash camp located in northern Jordan and Jordanian citizens from different cities in Jordan from October, 2021 to March, 2022. A Chi-square test was used to determine the differences in the experiences and perceptions of COVID-19 infection and vaccination between Palestinian refugees and resident Jordanian citizens. Logistic regression analysis was performed to predict factors associated with the beliefs, barriers and hesitancy towards COVID-19 vaccines.

    RESULTS: The total number of participants was 992, with 501 (50.5%) Palestinian refugees and 491 (49.5%) Jordanian citizens. Most participants (64.1%) who have never been tested for COVID-19 were from the refugees (P 

  9. Fulltext Experimental tissue mimicking human head phantom for estimation of stroke using IC-CF-DMAS algorithm in microwave based imaging system
    Islam MS, Islam MT, Almutairi AF
    Sci Rep, 2021 11 10;11(1):22015.
    PMID: 34759284 DOI: 10.1038/s41598-021-01486-x
    This paper presents the preparation and measurement of tissue-mimicking head phantom and its validation with the iteratively corrected coherence factor delay-multiply-and-sum (IC-CF-DMAS) algorithm for brain stroke detection. The phantom elements are fabricated by using different chemical mixtures that imitate the electrical properties of real head tissues (CSF, dura, gray matter, white matter, and blood/stroke) over the frequency band of 1-4 GHz. The electrical properties are measured using the open-ended dielectric coaxial probe connected to a vector network analyzer. Individual phantom elements are placed step by step in a three-dimensional skull. The IC-CF-DMAS image reconstruction algorithm is later applied to the phantom to evaluate the effectiveness of detecting stroke. The phantom elements are preserved and measured multiple times in a week to validate the overall performance over time. The electrical properties of the developed phantom emulate the similar properties of real head tissue. Moreover, the system can also effectively detect the stroke from the developed phantom. The experimental results demonstrate that the developed tissue-mimicking head phantom is time-stable, and it shows a good agreement with the theoretical results in detecting and reconstructing the stroke images that could be used in investigating as a supplement to the real head tissue.
  10. Fulltext Polarization insensitivity characterization of dual-band perfect metamaterial absorber for K band sensing applications
    Hakim ML, Alam T, Almutairi AF, Mansor MF, Islam MT
    Sci Rep, 2021 Sep 08;11(1):17829.
    PMID: 34497289 DOI: 10.1038/s41598-021-97395-0
    Polarization insensitive metamaterial absorbers (MA) are currently very attractive due to their unique absorption properties at different polarization angles. As a result, this type of absorber is widely used in sensing, imaging, energy harvesting, etc. This paper presents the design and characterization of a dual-band polarization-insensitive metamaterial absorber (MA) for K-band applications. The metamaterial absorber consists of two modified split ring resonators with an inner cross conductor to achieve a 90% absorption bandwidth of 400 MHz (21.4-21.8 GHz) and 760 MHz (23.84-24.24 GHz) at transverse electromagnetic (TEM), transverse electric (TE), and transverse magnetic (TM) mode. Polarization insensitivity of different incident angles for TE and TM mode is also investigated, which reveals a similar absorption behavior up to 90°. The metamaterial structure generates single negative (SNG) property at a lower frequency of 21.6 GHz and double negative property (DNG) at an upper frequency of 24.04 GHz. The permittivity and pressure sensor application are investigated for the proposed absorber, which shows its useability in these applications. Finally, a comparison with recent works is also performed to demonstrate the feasibility of the proposed structure for K band application, like sensor, filter, invasive clock, etc.
  11. Fulltext Realization of frequency hopping characteristics of an epsilon negative metamaterial with high effective medium ratio for multiband microwave applications
    Islam MT, Moniruzzaman M, Alam T, Samsuzzaman M, Razouqi QA, Almutairi AF
    Sci Rep, 2021 Aug 19;11(1):16898.
    PMID: 34413377 DOI: 10.1038/s41598-021-96228-4
    In this paper, a meander-lines-based epsilon negative (ENG) metamaterial (MTM) with a high effective medium ratio (EMR) and near-zero refractive index (NZI) is designed and investigated for multiband microwave applications. The metamaterial unit cell is a modification of the conventional square split-ring resonator in which the meander line concept is utilized. The meander line helps to increase the electrical length of the rings and provides strong multiple resonances within a small dimension. The unit cell of proposed MTM is initiated on a low-cost FR4 substrate of 1.5 mm thick and electrical dimension of 0.06λ × 0.06λ, where wavelength, λ is calculated at the lowest resonance frequency (2.48 GHz). The MTM provides four major resonances of transmission coefficient (S21) at 2.48, 4.28, 9.36, and 13.7 GHz covering S, C, X, and Ku bands. It shows negative permittivity, near-zero permeability, and near-zero refractive index in the vicinity of these resonances. The equivalent circuit is designed and modeled in Advanced Design System (ADS) software. The simulated S21 of the MTM unit cell is compared with the measured one and both show close similarity. The array performance of the MTM is also evaluated by using 2 × 2, 4 × 4, and 8 × 8 arrays that show close resemblance with the unit cell. The MTM offers a high effective medium ratio (EMR) of 15.1, indicating the design's compactness. The frequency hopping characteristics of the proposed MTM is investigated by open and short-circuited the three outer rings split gaps by using three switches. Eight different combinations of the switching states provide eight different sets of multiband resonances within 2-18 GHz; those give the flexibility of using the proposed MTM operating in various frequency bands. For its small dimension, NZI, high EMR, and frequency hopping characteristics through switching, this metamaterial can be utilized for multiband microwave applications, especially to enhance the gain of multiband antennas.
  12. Fulltext Associations between the indoor microbiome, environmental characteristics and respiratory infections in junior high school students of Johor Bahru, Malaysia
    Fu X, Yuan Q, Zhu X, Li Y, Meng Y, Hashim JH, et al.
    Environ Sci Process Impacts, 2021 Aug 01;23(8):1171-1181.
    PMID: 34278392 DOI: 10.1039/d1em00115a
    Pathogens are commonly present in the human respiratory tract, but symptoms are varied among individuals. The interactions between pathogens, commensal microorganisms and host immune systems are important in shaping the susceptibility, development and severity of respiratory diseases. Compared to the extensive studies on the human microbiota, few studies reported the association between indoor microbiome exposure and respiratory infections. In this study, 308 students from 21 classrooms were randomly selected to survey the occurrence of respiratory infections in junior high schools of Johor Bahru, Malaysia. Vacuum dust was collected from the floor, chairs and desks of these classrooms, and high-throughput amplicon sequencing (16S rRNA and ITS) and quantitative PCR were conducted to characterize the absolute concentration of the indoor microorganisms. Fifteen bacterial genera in the classes Actinobacteria, Alphaproteobacteria, and Cyanobacteria were protectively associated with respiratory infections (p < 0.01), and these bacteria were mainly derived from the outdoor environment. Previous studies also reported that outdoor environmental bacteria were protectively associated with chronic respiratory diseases, such as asthma, but the genera identified were different between acute and chronic respiratory diseases. Four fungal genera from Ascomycota, including Devriesia, Endocarpon, Sarcinomyces and an unclassified genus from Herpotrichillaceae, were protectively associated with respiratory infections (p < 0.01). House dust mite (HDM) allergens and outdoor NO2 concentration were associated with respiratory infections and infection-related microorganisms. A causal mediation analysis revealed that the health effects of HDM and NO2 were partially or fully mediated by the indoor microorganisms. This is the first study to explore the association between environmental characteristics, microbiome exposure and respiratory infections in a public indoor environment, expanding our understanding of the complex interactions among these factors.
  13. Fulltext An octa-band planar monopole antenna for portable communication devices
    Azim R, Alam T, Mia MS, Almutairi AF, Islam MT
    Sci Rep, 2021 Jul 27;11(1):15298.
    PMID: 34315996 DOI: 10.1038/s41598-021-94753-w
    Due to the rapid development of wireless communication systems, good numbers of services and devices use different frequency bands and protocols. To concurrently cover all these services, the antenna in communication devices should operate over multiple frequency bands. The use of wide and multi-band antennas not only reduces the number of antennas necessary to cover multiple frequency bands but also lessens the system complexity, size, and costs. To operate over eight frequency bands to cover sixteen well-established narrow service bands, a planar monopole antenna is proposed for portable communication devices. The proposed antenna is comprised of an inverted F-shaped monopole patch with a rotated L-shaped strip and an F-shaped ground strip with a rotated L-shaped branch. The studied antenna can excite at multiple resonant modes which helps it to achieve eight measured operating bands of 789-921 MHz, 1367-1651 MHz, 1995-2360 MHz, 2968-3374 MHz, 3546-3707, 4091-4405 MHz, 4519-5062 MHz and 5355-6000 MHz. The achieved measured operating bands can cover sixteen popular narrow service bands for 4G/3G/2G, MWT, WiFi, WiMAX, WLAN, and sub-6 GHz 5G wireless communication system. The studied antenna achieved good gain, efficiency and exhibits stable radiation characteristics. Moreover, the antenna does not use any lumped element and left ample space for other circuitries which makes it easier to use in portable devices such as tablets, laptops, etc. with low manufacturing cost.
  14. Fulltext Metamaterial array based meander line planar antenna for cube satellite communication
    Alam T, Almutairi AF, Samsuzzaman M, Cho M, Islam MT
    Sci Rep, 2021 Jul 08;11(1):14087.
    PMID: 34238984 DOI: 10.1038/s41598-021-93537-6
    This research article presents a design and performance analysis of a metamaterial inspired ultra-high frequency (UHF) compact planar patch antenna for the CubeSat communication system that could be smoothly integrated with commercially available 2U Cube Satellite structure and onboard subsystem. The proposed antenna consists of two layers, one is two different width meander line antenna patch with partial ground plane and another layer is 3 × 2 near-zero-indexed metamaterial (NZIM) metamaterial array structure with ground plane. The NZIM array layer has been utilized to minimize the coupling effect with Cube Satellite structure and improve the frequency stability with enhanced antenna gain and efficiency. The fabricated antenna can operate within the lower UHF frequency band of 443.5-455 MHz. with an average peak gain of 2.5 dB. The designed antenna impedance stability characteristic has been explored after integration with the 2U Cube Satellite body layout. Besides, the antenna communication performance has been verified using 2U Cube Satellite free space path loss investigation. Small antenna volume with trade-off between the antenna size and performance are the key advantages of the proposed design, as the antenna occupies only 80 × 40 × 3.35 mm3 space of the 2U Cube Satellite body structure and the geometrical parameters can be designed to provide the best performance between 449 and 468.5 MHz.
  15. Fulltext Asthma symptoms and respiratory infections in Malaysian students-associations with ethnicity and chemical exposure at home and school
    Norbäck D, Hashim Z, Ali F, Hashim JH
    Environ Res, 2021 06;197:111061.
    PMID: 33785322 DOI: 10.1016/j.envres.2021.111061
    Little is known on respiratory effects of indoor chemicals in the tropics. We investigated associations between asthma and respiratory infections in Malaysian students and chemical exposure at home and at school. Moreover, we investigated differences in home environment between the three main ethnic groups in Malaysia (Malay, Chinese, Indian). Totally, 462 students from 8 junior high schools in Johor Bahru participated (96% participation rate). The students answered a questionnaire on health and home environment. Climate, carbon dioxide (CO2), volatile organic compounds (VOC), formaldehyde and nitrogen dioxide (NO2) were measured inside and outside the schools. Multilevel logistic regression was applied to study associations between exposure and health. Totally 4.8% were smokers, 10.3% had wheeze, 9.3% current asthma, and had 18.8% any respiratory infection in the past 3 months. Malay students had more dampness or mould (p 
  16. Fulltext Fabrication and Characterization of Physical and Mechanical Properties of Carbon Nanotubes-Graphene-Based Sandwich Composite Pressure Sensor
    Ali A, Ali F, Rashedi A, Armghan A, Fajita MRN, Alenezi F, et al.
    Nanomaterials (Basel), 2021 May 13;11(5).
    PMID: 34068218 DOI: 10.3390/nano11051284
    In this work, piezoresistive properties of graphene-multiwalled carbon nanotubes (MWCNTs) composites are investigated, characterized, and compared. Sandwich-type composite piezoresistive pressure-sensitive sensors (Ag/Graphene-MWCNT/Ag) with the same diameters, but different fabrication pressures and thicknesses were fabricated using the mortar and pestle/hydraulic press technique. To produce low-electrical-resistance contacts, both sides of the composite sensors were painted with silver (Ag) paste. All the sensors showed reductions in the direct current (DC) resistance 'R' with an increment in external uniaxial applied pressure. However, it was observed that higher fabrication pressure led to a lower resistance value of the composite, while the thicker samples give lower electrical conductivity and higher resistance than the thinner samples. The experimental data for all composite pressure sensors were in excellent agreement with the simulated results.
  17. Fulltext Characteristics of a Plasticized PVA-Based Polymer Electrolyte Membrane and H+ Conductor for an Electrical Double-Layer Capacitor: Structural, Morphological, and Ion Transport Properties
    Brza MA, Aziz SB, Anuar H, Alshehri SM, Ali F, Ahamad T, et al.
    Membranes (Basel), 2021 Apr 20;11(4).
    PMID: 33923927 DOI: 10.3390/membranes11040296
    Poly (vinyl alcohol) (PVA)-based solid polymer electrolytes doped with ammonium thiocyanate (NH4SCN) and glycerol were fabricated using a solution casting method. Lithium-based energy storage devices are not environmentally friendly materials, and they are toxic. Thus, proton-conducting materials were used in this work as they are harmless and are smaller than lithium. The interaction between PVA and the electrolyte elements was shown by FTIR analysis. The highest conductivity of 1.82 × 10-5 S cm-1 was obtained by the highest-conducting plasticized system (PSP_2) at room temperature. The mobility, diffusion coefficient, and number density of anions and cations were found to increase with increasing glycerol. FESEM was used to investigate the influence of glycerol on film morphology. TNM showed that the cations and anions were the main charge carriers. LSV showed that the electrochemical stability window of the PSP_2 system was 1.99 V. The PSP_2 system was applied in the preparation of an electrical double layer capacitor device. The shape of the cyclic voltammetry (CV) curve was nearly rectangular with no Faradaic peaks. From the galvanostatic charge-discharge analysis, the power density, energy density, and specific capacitance values were nearly constant beyond the first cycle at 318.73 W/Kg, 2.06 Wh/Kg, and 18.30 F g-1, respectively, for 450 cycles.
  18. Fulltext UV-LED as a New Emerging Tool for Curable Polyurethane Acrylate Hydrophobic Coating
    Ghazali SK, Adrus N, Majid RA, Ali F, Jamaluddin J
    Polymers (Basel), 2021 Feb 04;13(4).
    PMID: 33557118 DOI: 10.3390/polym13040487
    The elimination of mercury, low energy consumption, and low heat make the ultraviolet light-emitting diode (UV-LED) system emerge as a promising alternative to conventional UV-mercury radiation coating. Hence, a series of hydrophobic coatings based on urethane acrylate oligomer and fluorinated monomer via UV-LED photopolymerisation was designed in this paper. The presence of fluorine component at 1160 cm-1, 1235 cm-1, and 1296 cm-1 was confirmed by Fourier Transform Infra-Red spectroscopy. A considerably high degree C=C conversion (96-98%) and gel fraction (95-93%) verified the application of UV-LED as a new technique in radiation coating. It is well-accepted that fluorinated monomer can change the surface wettability as the water contact angle of the coating evolved from 88.4° to 121.2°, which, in turn, reduced its surface free energy by 70.5%. Hence, the hydrophobicity of the coating was governed by the migration of the fluorine component to the coating surface as validated by scanning electron and atomic force microscopies. However, above 4 phr of fluorinated monomer, the transparency of the cured coating examined by UV-visible spectroscopy experienced approximately a 16% reduction. In summary, the utilisation of UV-LED was a great initiative to develop green aspect in photopolymerisation, particularly in coating technology.
  19. Fulltext Depletion of psychological, financial, and social resources in the hospitality sector during the pandemic
    Nisar QA, Haider S, Ali F, Naz S, Ryu K
    Int J Hosp Manag, 2021 Feb;93:102794.
    PMID: 33519016 DOI: 10.1016/j.ijhm.2020.102794
    This study details how psychological, financial, and social factors shape employee deviant interpersonal behaviors during a pandemic. Data were collected with a survey of 372 front-line employees of hotels and analyzed with PLS-SEM. The findings showed social disconnectedness and perceived risk of unemployment leads to perceived isolation, which further creates depression in employees. The findings also showed that depression is positively related to employee deviance. Financial strain is a major cause of perceived isolation, depression, and deviant behaviors among front-line employees. Results also proved that social support reduces fear of isolation, depression, and employee deviance. This study provides guidelines that hotels need to understand the psychological stance of employees and design policies to overcome employee perceived fears and psychological disorders.
  20. Fulltext Indole-3-acetamides: As Potential Antihyperglycemic and Antioxidant Agents; Synthesis, In Vitro α-Amylase Inhibitory Activity, Structure-Activity Relationship, and In Silico Studies
    Kanwal, Khan KM, Chigurupati S, Ali F, Younus M, Aldubayan M, et al.
    ACS Omega, 2021 Jan 26;6(3):2264-2275.
    PMID: 33521466 DOI: 10.1021/acsomega.0c05581
    Indole-3-acetamides (1-24) were synthesized via coupling of indole-3-acetic acid with various substituted anilines in the presence of coupling reagent 1,1-carbonyldiimidazole. The structures of synthetic molecules were elucidated through different spectroscopic techniques including electron ionization-mass spectroscopy (EI-MS), 1H-, 13C NMR, and high-resolution EI-MS (HREI-MS). These compounds were screened for their antihyperglycemic and antioxidant potentials. All compounds displayed good to moderate inhibition against α-amylase enzyme with IC50 values ranging between 1.09 ± 0.11 and 2.84 ± 0.1 μM compared to the standard acarbose (IC50 = 0.92 ± 0.4 μM). Compound 15 (IC50 = 1.09 ± 0.11 μM) was the most active compound of the series and exhibited good inhibition against α-amylase; in addition, this compound also exhibited good antioxidant potential with IC50 values of 0.35 ± 0.1 and 0.81 ± 0.25 μM in 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, respectively. The binding interactions of synthetic molecules with the enzyme's active site were confirmed via in silico studies. The current study had identified a number of lead molecules as potential antihyperglycemic and antioxidant agents.
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