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  1. Sheikh MR, Islam MM, Himel GMS
    Data Brief, 2024 Apr;53:110149.
    PMID: 38379887 DOI: 10.1016/j.dib.2024.110149
    This article introduces a comprehensive dataset designed for researchers to classify diseases in Luffa leaves, determine the grade of Luffa from Luffa images, and identify different growth stages throughout the year. The dataset is meticulously organized into three sections, each concentrating on specific facets of Luffa Aegyptiaca, commonly known as Smooth Luffa (Dhundol/). These images were captured in various village fields in Faridpur, Bangladesh. The sections include the assessment of Smooth Luffa quality, the identification of plant diseases, and the documentation of Luffa flowers. The dataset is divided into three sections, totaling 1933 original JPG images. The "Luffa Diseases" section features images of smooth Luffa leaves, depicting various diseases and unaffected leaves. Categories in this section encompass Alternaria Disease, Angular Spot Disease, Holed Leaves, Mosaic Virus, and Fresh Leaves, totaling 1228 JPG raw images. The "Flowers" category comprises 362 JPG raw images, showcasing different maturity stages in smooth Luffa flowers. Finally, the "Luffa Grade" section focuses on categorizing smooth Luffa into fresh and defective categories, presenting 343 JPG raw images for this purpose.
  2. Mubashir M, Jusoh N, Majeed Z, Rambabu K, Banat F, Tao Y
    J Hazard Mater, 2020 Oct 27.
    PMID: 33153798 DOI: 10.1016/j.jhazmat.2020.124345
    This article has been withdrawn at the request of the editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.
  3. Ahmad W, Sarwar M, Shah K, Ahmadian A, Salahshour S
    Math Methods Appl Sci, 2021 Feb 03.
    PMID: 33821069 DOI: 10.1002/mma.7241
    In this manuscript, the mathematical model of COVID-19 is considered with eight different classes under the fractional-order derivative in Caputo sense. A couple of results regarding the existence and uniqueness of the solution for the proposed model is presented. Furthermore, the fractional-order Taylor's method is used for the approximation of the solution of the concerned problem. Finally, we simulate the results for 50 days with the help of some available data for fractional differential order to display the excellency of the proposed model.
  4. Baraya YS, Yankuzo HM, Wong KK, Yaacob NS
    J Ethnopharmacol, 2021 Mar 01;267:113522.
    PMID: 33127562 DOI: 10.1016/j.jep.2020.113522
    ETHNOPHARMACOLOGICAL RELEVANCE: Locally known as 'pecah batu', 'bayam karang', 'keci beling' or 'batu jin', the Malaysian medicinal herb, Strobilanthes crispus (S. crispus), is traditionally used by the local communities as alternative or adjuvant remedy for cancer and other ailments and to boost the immune system. S. crispus has demonstrated multiple anticancer therapeutic potential in vitro and in vivo. A pharmacologically active fraction of S. crispus has been identified and termed as F3. Major constituents profiled in F3 include lutein and β-sitosterol.

    AIM OF THE STUDY: In this study, the effects of F3, lutein and β-sitosterol on tumor development and metastasis were investigated in 4T1-induced mouse mammary carcinoma model.

    MATERIALS AND METHODS: Tumor-bearing mice were fed with F3 (100 mg/kg/day), lutein (50 mg/kg/day) and β-sitosterol (50 mg/kg/day) for 30 days (n = 5 each group). Tumor physical growth parameters, animal body weight and development of secondary tumors were investigated. The safety profile of F3 was assessed using hematological and histomorphological changes on the major organs in normal control mice (NM).

    RESULTS: Our findings revealed significant reduction of physical tumor growth parameters in all tumor-bearing mice treated with F3 (TM-F3), lutein (TM-L) or β-sitosterol (TM-β) as compared with the untreated group (TM). Statistically significant reduction in body weight was observed in TM compared to the NM or treated (TM-F3, TM-L and TM-β) groups. Histomorphological examination of tissue sections from the F3-treated group showed normal features of the vital organs (i.e., liver, kidneys, lungs and spleen) which were similar to those of NM. Administration of F3 to NM mice (NM-F3) did not cause significant changes in full blood count values.

    CONCLUSION: F3 significantly reduced the total tumor burden and prevented secondary tumor development in metastatic breast cancer without significant toxicities in 4T1-induced mouse mammary carcinoma model. The current study provides further support for therapeutic development of F3 with further pharmacokinetics studies.

  5. Syed A, Azhar S, Raza MM, Saeed H, Jamshed SQ
    Pharmacy (Basel), 2018 Mar 31;6(2).
    PMID: 29614725 DOI: 10.3390/pharmacy6020029
    OBJECTIVES: Pharmacovigilance in Pakistan needs robust preference in terms of implementation and consistent movement of structured approaches. The objective of this study is to explore the knowledge, attitude and barriers towards adverse drug reaction (ADR) reporting among physicians and pharmacists and to explore the encouraging factors of ADR reporting.

    METHODS: The current research was a cross-sectional study design in which a pre-validated questionnaire was administered to physicians and pharmacists in Abbottabad, Pakistan. The study was conducted for two months from January 2016 to February 2016.

    RESULTS: A total of 194 physicians and pharmacists responded with a response rate of 35.3%. All the respondents either strongly agreed or agreed that ADRs reporting is a part of their duty. Half of the respondents agreed that monitoring of drug safety is important. Around three quarters of respondents (74.2%) stated that they did not report ADRs due to unavailability of reporting forms while 70% cited lack of a proper pharmacovigilance center as one of the key barriers. Half of the respondents (52.2%) did not report due to their insufficient knowledge. A large majority (81.8%) said that they would report ADRs if there is pharmacovigilance center. On the point of incentives, opinion seems to be divided. Slightly less than half (47.8%) cited their wish to have few incentives while the remaining 52.2% either preferred to be neutral or disagreed.

    CONCLUSION: Based on the study findings, barriers were mostly related to general unfamiliarity with ADRs reporting guidelines and the non-existence of a pharmacovigilance center. It is highlighted that the regulatory body should carve a niche for a properly functional pharmacovigilance center and initiate educational programs for strengthening knowledge and attitudes towards ADR reporting.

  6. Ali I, Ijaz M, Rehman IU, Rahim A, Ata H
    Front Public Health, 2018;6:173.
    PMID: 29998091 DOI: 10.3389/fpubh.2018.00173
    Objective: This study intends to evaluate the knowledge, attitude and awareness of medical doctors toward influenza vaccination and the reasons for not getting vaccinated. Methods: A cross-sectional study was carried out among medical doctors in three major tertiary care health settings in Peshawar, Khyber Pakhtunkhwa (KP), Pakistan. A web-based, pre-tested questionnaire was used for data collection. Results: A total of (n = 300) medical doctors were invited, however only (n = 215) participated in the study with a response rate of 71.7%. Among the participants, 95.3% (n = 205) were males with a mean age of 28.67 ± 3.89 years. By designation, 121(56.3%) were trainee medical officers and 40 (18.6%) were house officers. The majority 102(47.4%) had a job experience of 1-2 years. Of the total sample, 38 (17.7%) doctors reported having received some kind of vaccination, whereas only 19 (8.84%) were vaccinated against influenza. The results identified that the major barriers toward influenza vaccinations included (1) Unfamiliarity with Influenza vaccination availability (Relative Importance Index RII = 0.830), (2) Unavailability of Influenza vaccines due to lack of proper storage area in the institution (RII = 0.634), (3) Cost of vaccine (RII = 0.608), and (4) insufficient staff to administer vaccine (RII = 0.589). Additionally, 156 (72.6%) of doctors were not aware of the influenza immunization recommendation and guidelines published by the Advisory Committee on Immunization Practices (ACIP) and Centre for Disease Control and Prevention (CDC). Physicians obtained a high score (8.27 ± 1.61) of knowledge and understanding regarding influenza and its vaccination followed by medical officers (8.06 ± 1.37). Linear Regression analysis revealed that gender was significantly associated with the knowledge score with males having a higher score (8.0± 1.39) than females (6.80 ± 1.61 β = -1.254 and CI [-2.152 to -0.355], p = 0.006). Conclusion: A very low proportion of doctors were vaccinated against influenza, despite the published guidelines and recommendations. Strategies that address multiple aspects like increasing awareness and the importance of the influenza vaccine, the international recommendations and enhancing access and availability of the vaccine are needed to improve its coverage and health outcomes.
  7. Abu Bakar N', Hakim Abdullah MN, Lim V, Yong YK
    PMID: 35069762 DOI: 10.1155/2022/6098929
    Peptic ulcer disease is a multifactorial disorder and is the most significant public health concern nowadays. Previous study showed that essential oil extracted from Momordica charantia's seed exhibited gastroprotective effect. However, the evidence for the gastroprotective effect of its active compound, polypeptide K (PPK), remains unclear. This study aimed to examine the preventive effect of PPK against different experimental gastric lesions models in rats. The possible gastroprotective effect of PPK was assessed in hydrochloride ethanol- and indomethacin-induced gastric ulcer models in Sprague Dawley rats and was further evaluated macroscopically and microscopically. Pyloric ligation experiments were used to investigate gastric secretion. Oral administration of PPK at all concentrations (10, 25, and 50 mg/kg) showed significant (p < 0.05) reduction in total area of lesion in both hydrochloride ethanol- and indomethacin-induced gastric ulcer models. The highest inhibition rate was seen in PPK dose of 50 mg/kg with 64.9% and 72.2% on hydrochloride ethanol and indomethacin models, respectively. Microscopically, PPK preserved the normal architectures of the gastric tissues from being damaged by hydrochloride ethanol and indomethacin. Further, in the pyloric ligation studies, PPK significantly (p < 0.05) decreased the ulcer area where the highest protection was exhibited by 50 mg/kg with 70% inhibition rate. Moreover, all concentrations of PPK also significantly (p < 0.05) enhanced the gastric wall mucus secretion. Collectively, this study demonstrated the gastroprotective effect of PPK on hydrochloride ethanol- and indomethacin-induced gastric ulcer models. The possible mechanism might be associated with enhanced mucus secretion and thus lowering the total acidity.
  8. Bian J, Zhu S, Ma W, Li C, Ashraf MA
    Saudi Pharm J, 2016 May;24(3):354-62.
    PMID: 27275127 DOI: 10.1016/j.jsps.2016.04.017
    This study is to establish a model of rat tibial osteocarcinoma pain, intrathecally inject specific ERK1/2 inhibitors SCH772984, observe the analgesic effect, and discuss the influence of ERK-P90RSK-Fos signal path in bone cancer pain. Forty female SD rats were randomly divided into 5 groups. Establish a bone cancer pain model after putting the intrathecal tube 5d and determine the rats' mechanical withdrawal threshold (MWT) after tube 5d; 40 SD rats with intrathecal tube back 5d were randomly divided into 5 groups. Sham Group receives no medication, the other four respectively receive 5% DMSO 10 μl, SCH 0.1, 1.0, 10 μg (SCH dissolved in 10 μl 5% DMSO) intrathecally. Determine the rats' mechanical withdrawal threshold (MWT) before and after giving medication 1, 3, 6, 9, 12, 15, 18, 24 h, and 2 min spontaneous paw withdrawal. Western blot and immuno-fluorescence determine the expression condition of spinal cord dorsal horn of p-ERK, p-p90RSK and Fos protein. Intrathecal injection of SCH772984 has analgesic effects on rats with bone cancer pain, and the effects enhance with increasing dose; intrathecal injection of SCH772984 10 μg could greatly reduce the expression of spinal dorsal horn Fos protein. Injecting walker 256 tumor cells into rats' tibia could cause behavior changes, such as idiopathic pain sensitivity and pain; the intrathecal tube almost has no effect on motor function of rats; ERK1/2 is involved in bone cancer pain, and intrathecal injection of ERK1/2 specific inhibitors SCH772984 10 μg may effectively relieve bone cancer pain.
  9. İlbasmış M, Çitil M, Demirtaş F, Ali M, Barut A, Mohsin M
    Environ Sci Pollut Res Int, 2023 Aug;30(38):89726-89739.
    PMID: 37460882 DOI: 10.1007/s11356-023-28544-3
    The aim of this study is to examine the effect of green investments on air quality for developed and developing European countries. In this context, the short- and long-term effects of green investments on air quality were examined by panel generalized method of moments (GMM) and panel causality method. As a result of the GMM analysis, it has been determined that green investments negatively affect the air quality for both developed European countries and developing European countries in the short term, but this effect turns positive in developed countries in the long term. As a result of the panel causality analysis, two-way causality was determined between air quality and green investments.
  10. Nawawi MH, Mohamad R, Tahir PM, Saad WZ
    Int Sch Res Notices, 2017;2017:7831954.
    PMID: 28523288 DOI: 10.1155/2017/7831954
    Microbial xylanase and pectinase are two extremely valuable enzymes, which have captivated much attention. This can be seen from the increased demand for these enzymes by many industrial sectors. This study investigates the isolation and screening of extracellular xylanopectinolytic enzymes-producing bacteria in a submerged fermentation (SmF). Samples are collected from the compost of empty fruit bunch (EFB) at Biocompost Pilot Plant, located at Biorefinery Plant, Universiti Putra Malaysia. From the experiment, out of 20 isolates, 11 isolates show xylanase or/and pectinase activity, and only one isolate (EFB-11) shows the concurrent activities of xylanase and pectinase. These activities are selected for enzyme production under submerged fermentation (quantitative screening). At the 72nd hour of incubation, xylanase and pectinase show the highest production, which ranges about 42.33 U/mL and 62.17 U/mL (with low amount of cellulase present), supplemented with 2% (w/v) of rice bran as carbon source at incubation temperature level, which is 30°C. Meanwhile, the pH of media is shifted to 8.42, which indicates that EFB-11 isolate is alkalotolerant bacteria and identified as Bacillus subtilis ADI1. This strain proves to have potential in agroindustrial bioconversion and has a promising ability to scale up to an industrial scale.
  11. Ben Abdallah A, Becha H, Sharif A, Bashir MF
    Environ Sci Pollut Res Int, 2024 Mar;31(14):21935-21946.
    PMID: 38400971 DOI: 10.1007/s11356-024-32565-x
    The rapid rise in climate and ecological challenges have allowed policymakers to introduce stringent environmental policies. In addition, financial limitations may pose challenges for countries looking to green energy investments as energy transition is associated with geopolitical risks that could create uncertainty and dissuade green energy investments. The current study uses PTR and PSTR as econometric strategy to investigate how geopolitical risks and financial development indicators influence energy transition in selected industrial economies. Our findings indicate a non-linear DCPB-RE relationship with a threshold equal to 39.361 in PTR model and 35.605 and 122.35 in PSTR model. Additionally, when the threshold was estimated above, financial development indicators and geopolitical risk positively impacts renewable energy. This confirms that these economies operate within a geopolitical context, with the objective of investing more in clean energy. We report novel policy suggestion to encourage policymakers promoting energy transition and advance the sustainable financing development and ecological sustainability.
  12. Al-Maari MA, Hizaddin HF, Salleh MZM, Hayyan A
    J Mol Model, 2024 Feb 17;30(3):73.
    PMID: 38368310 DOI: 10.1007/s00894-024-05876-6
    CONTEXT: One of the prevalent methods for evaluating separation performance is to predict the interactions of solvent and solute molecules. The infinite dilution activity coefficient, Gibbs free energy, and sigma profiles provided insights into the solubilization of a solute and revealed the intensity of the solution's molecular interactions. The effective thermodynamic tools (infinite dilution activity coefficient, Gibbs free energy) were evaluated for predicting the efficiency of 18 polar and non-polar organic solvents in rubber seed oil (RSO) extraction. An infinite dilution activity coefficient was computed to evaluate the solubility of the rubber seed oil model compound (linoleic acid) in the organic solvents. Gibbs free energy was evaluated to show the energy change associated with the molecules mixing process and forecast the miscibility of linoleic acid molecules in the solvents. Moreover, the study examined the sigma profiles and sigma surfaces of organic solvents and linoleic acid to acquire a deeper insight into their similarities and how they interact molecularly. According to the computational prediction and experimental verification, the thermodynamic properties of Gibbs free energy and activity coefficient proved to be highly effective tools for screening polar and moderately polar solvents, predicting the molecular interactions with solute. Whereas the sigma profile and sigma surface were found to be the most efficient tools for evaluating the efficacy of non-polar solvents. Solvents with moderate polarity, such as tetrahydrofuran and diethyl ether, as well as non-polar solvents like pentane, heptane, and n-hexane, proved to be effective and favorable for oil extraction, resulting in the highest oil yields of approximately 27.0%. Overall, the COSMO-RS method demonstrates its utility in estimating the solubility of RSO in organic solvents, enabling early identification of the most effective solvent.

    METHODS: The initial geometry optimization of every component was conducted through density functional theory (DFT) using TmoleX software. A single-point density functional theory (DFT) computation using Becke Perdew 86 (BP86) and the Triple-Zeta Valence Potential (TZVPD) was performed to produce.cosmo files. COSMO-RS calculations were performed by applying the parameterization file BP_TZVPD_FINE_19.ctd using COSMOthermX software. The practical extraction of oil from plant seeds was performed using a sonicator bath to verify the accuracy of the COSMO-RS predictions.

  13. Khaidzir S, Masri AN, Ruslan MSH, Abdul Mutalib MI
    ACS Omega, 2021 Apr 13;6(14):9629-9637.
    PMID: 33869943 DOI: 10.1021/acsomega.1c00189
    In this study, piperidinium-based ionic liquids (IL) containing trifluoromethanesulfonate, phenolate, and dicyanamide anions were synthesized. Using the ILs, extraction of naphthenic acid from highly acidic oil with a total acid number (TAN) of 1.44 was studied. Two agitation techniques have been implemented for the extraction process, which were mechanical stirring and ultrasonic-assisted irradiation. 1-Butyl-1-methylpiperidinium phenolate [BMPi][Phe] showed the best potential in extracting naphthenic acid from oil, with complete removal of naphthenic acid with IL-to-oil ratios of 0.010 and 0.0025 for the mechanical stirring method and the ultrasonic-assisted method, respectively. Ultrasonic-assisted extraction process shows very good potential in enhancing the extraction efficiency of naphthenic acid. Optimization and study on the effects of ultrasonic parameters, namely, IL-to-oil ratio, ultrasonic amplitude, and time, were studied through response surface methodology (RSM). Using [BMPi][Phe], the optimum conditions obtained are IL-to-oil ratio of 0.03, 53.91% of amplitude, and 4.29 min of extraction time. Under these optimum conditions, 100% removal of naphthenic acid was achieved.
  14. Jiee SF, Bondi ME, Emiral ME, Jantim A
    J Prim Care Community Health, 2021;12:21501327211029800.
    PMID: 34218701 DOI: 10.1177/21501327211029800
    BACKGROUND: Polio Supplementary Immunization Activities (SIAs) were carried out in the State of Sabah in response to the Vaccine Derived Poliovirus outbreak declared in December 2019. Prior to this, Malaysia had been polio-free over the past 27 years. This paper reported on the successful implementation of SIAs in the district of Penampang, Sabah, adapting (vaccine administration) to the COVID-19 pandemic.

    METHODS: A series of meticulous planning, healthcare staff training, advocacy, and community engagement activities were conducted by the Penampang District Health Office. Bivalent Oral Polio Vaccine (bOPV) and monovalent Oral Polio Vaccine were administered over the period of 1 year via these methods: house to house, drive-through, static, and mobile posts. The targeted group was 22 096 children aged 13 years and below.

    RESULTS: Polio SIAs in Penampang managed to achieve more than 90% coverage for both bOPV and mOPV. The overall vaccine wastage was reported to be 1.63%. No major adverse reaction was reported.

    CONCLUSION: High vaccine uptake during Polio SIAs in Penampang was attributed to good inter-agency collaboration, community engagement, intensified health promotion activities, and drive-through vaccination campaign.

  15. Fayyaz Z, Farrukh MA, Ul-Hamid A, Chong KK
    Microsc Res Tech, 2024 May;87(5):957-976.
    PMID: 38174385 DOI: 10.1002/jemt.24487
    The present exploration demonstrates the efficient, sustainable, cost-effective, and environment-friendly green approach for the synthesis of silver (Ag)-doped copper oxide (CuO) embedded with reduced graphene oxide (rGO) nanocomposite using the green one-pot method and the green deposition method. Leaf extracts of Ficus carica and Azadirachta indica were used for both methods as reducing and capping agents. The effect of methodology and plant extract was analyzed through different characterization techniques such as UV-visible spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), x-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM). The lowest band gap of 3.0 eV was observed for the Ag/CuO/rGO prepared by the green one-pot method using F. carica. The reduction of graphene oxide (GO) and the formation of metal oxide was confirmed through functional group detection using FT-IR. Calculation of thermodynamic parameters showed that all reactions involved were nonspontaneous and endothermic which shows the stability of nanocomposites. XRD studies revealed the crystallinity, phase purity and small average crystallite size of 32.67 nm. SEM images disclosed that the morphology of the nanocomposites was spherical with agglomeration and rough texture. The particle size of the nanocomposites calculated through HRTEM was found in agreement with the XRD results. The numerous properties of the synthesized nanocomposites enhanced their potential against the degradation of methylene blue, rhodamine B, and ciprofloxacin. The highest percentage degradation of Ag/CuO/rGO was found to be 97%, synthesized using the green one-pot method with F. carica against ciprofloxacin, which might be due to the lowest band gap, delayed electron-hole pair recombination, and large surface area available. The nanocomposites were also tested against the Gram-positive and Gram-negative bacteria. RESEARCH HIGHLIGHTS: Facile synthesis of Ag/CuO/rGO nanocomposite using a green one-pot method and the green deposition method. The lowest band gap of 3.0 eV was observed for nanocomposite prepared by a green one-pot method using Ficus carica. Least average crystallite size of 32.67 nm was found for nanocomposite prepared by a green one-pot method using F. carica. Highest antibacterial and catalytic activity (97%) was obtained against ciprofloxacin with nanocomposite prepared through green one-pot method using F. carica. A mechanism of green synthesis is proposed.
  16. Hassan R, Aslam Khan MU, Abdullah AM, Abd Razak SI
    Polymers (Basel), 2021 Apr 27;13(9).
    PMID: 33925332 DOI: 10.3390/polym13091409
    Polymeric materials have always established an edge over other classes of materials due to their potential applications in various fields of biomedical engineering. Orthodontics is an emerging field in which polymers have attracted the enormous attention of researchers. In particular, thermoplastic materials have a great future utility in orthodontics, both as aligners and as retainer appliances. In recent years, the use of polycarbonate brackets and base monomers bisphenol A glycerolate dimethacrylate (bis-GMA) has been associated with the potential release of bisphenol A (BPA) in the oral environment. BPA is a toxic compound that acts as an endocrine disruptor that can affect human health. Therefore, there is a continuous search for non-BPA materials with satisfactory mechanical properties and an esthetic appearance as an alternative to polycarbonate brackets and conventional bis-GMA compounds. This study aims to review the recent developments of BPA-free monomers in the application of resin dental composites and adhesives. The most promising polymeric smart materials are also discussed for their relevance to future orthodontic applications.
  17. Saqib M, Khan I, Shafie S, Mohamad AQ
    Sci Rep, 2021 Feb 12;11(1):3725.
    PMID: 33580116 DOI: 10.1038/s41598-020-78421-z
    The colloidal suspension of nanometer-sized particles of Fe3O4 in traditional base fluids is referred to as Ferro-nanofluids. These fluids have many technological applications such as cell separation, drug delivery, magnetic resonance imaging, heat dissipation, damping, and dynamic sealing. Due to the massive applications of Ferro-nanofluids, the main objective of this study is to consider the MHD flow of water-based Ferro-nanofluid in the presence of thermal radiation, heat generation, and nanoparticle shape effect. The Caputo-Fabrizio time-fractional Brinkman type fluid model is utilized to demonstrate the proposed flow phenomenon with oscillating and ramped heating boundary conditions. The Laplace transform method is used to solve the model for both ramped and isothermal heating for exact solutions. The ramped and isothermal solutions are simultaneously plotted in the various figures to study the influence of pertinent flow parameters. The results revealed that the fractional parameter has a great impact on both temperature and velocity fields. In the case of ramped heating, both temperature and velocity fields decreasing with increasing fractional parameter. However, in the isothermal case, this trend reverses near the plate and gradually, ramped, and isothermal heating became alike away from the plate for the fractional parameter. Finally, the solutions for temperature and velocity fields are reduced to classical form and validated with already published results.
  18. Sundararaju U, Mohammad Haniff MAS, Ker PJ, Menon PS
    Materials (Basel), 2021 Mar 29;14(7).
    PMID: 33805402 DOI: 10.3390/ma14071672
    A photodetector converts optical signals to detectable electrical signals. Lately, self-powered photodetectors have been widely studied because of their advantages in device miniaturization and low power consumption, which make them preferable in various applications, especially those related to green technology and flexible electronics. Since self-powered photodetectors do not have an external power supply at zero bias, it is important to ensure that the built-in potential in the device produces a sufficiently thick depletion region that efficiently sweeps the carriers across the junction, resulting in detectable electrical signals even at very low-optical power signals. Therefore, two-dimensional (2D) materials are explored as an alternative to silicon-based active regions in the photodetector. In addition, plasmonic effects coupled with self-powered photodetectors will further enhance light absorption and scattering, which contribute to the improvement of the device's photocurrent generation. Hence, this review focuses on the employment of 2D materials such as graphene and molybdenum disulfide (MoS2) with the insertion of hexagonal boron nitride (h-BN) and plasmonic nanoparticles. All these approaches have shown performance improvement of photodetectors for self-powering applications. A comprehensive analysis encompassing 2D material characterization, theoretical and numerical modelling, device physics, fabrication and characterization of photodetectors with graphene/MoS2 and graphene/h-BN/MoS2 heterostructures with plasmonic effect is presented with potential leads to new research opportunities.
  19. Khan MA, Nayan N, Shadiullah, Ahmad MK, Soon CF
    Nanomaterials (Basel), 2020 Jul 02;10(7).
    PMID: 32630689 DOI: 10.3390/nano10071298
    In the present work, a facile one-step hydrothermal synthesis of well-defined stabilized CuO nanopetals and its surface study by advanced nanocharacterization techniques for enhanced optical and catalytic properties has been investigated. Characterization by Transmission electron microscopy (TEM) analysis confirmed existence of high crystalline CuO nanopetals with average length and diameter of 1611.96 nm and 650.50 nm, respectively. The nanopetals are monodispersed with a large surface area, controlled morphology, and demonstrate the nanocrystalline nature with a monoclinic structure. The phase purity of the as-synthesized sample was confirmed by Raman spectroscopy and X-ray diffraction (XRD) patterns. A significantly wide absorption up to 800 nm and increased band gap were observed in CuO nanopetals. The valance band (VB) and conduction band (CB) positions at CuO surface are measured to be of +0.7 and -1.03 eV, respectively, using X-ray photoelectron spectroscopy (XPS), which would be very promising for efficient catalytic properties. Furthermore, the obtained CuO nanopetals in the presence of hydrogen peroxide ( H 2 O 2 ) achieved excellent catalytic activities for degradation of methylene blue (MB) under dark, with degradation rate > 99% after 90 min, which is significantly higher than reported in the literature. The enhanced catalytic activity was referred to the controlled morphology of monodispersed CuO nanopetals, co-operative role of H 2 O 2 and energy band structure. This work contributes to a new approach for extensive application opportunities in environmental improvement.
  20. Ali NA, Sazelee N, Yahya MS, Ismail M
    Front Chem, 2020;8:457.
    PMID: 32656179 DOI: 10.3389/fchem.2020.00457
    In this study, the modification of the desorption behavior of LiAlH4 by the addition of K2NbF7 was explored for the first time. The addition of K2NbF7 causes a notable improvement in the desorption behavior of LiAlH4. Upon the addition of 10 wt.% of K2NbF7, the desorption temperature of LiAlH4 was significantly lowered. The desorption temperature of the LiAlH4 + 10 wt.% K2NbF7 sample was lowered to 90°C (first-stage reaction) and 149°C (second-stage reaction). Enhancement of the desorption kinetics performance with the LiAlH4 + 10 wt.% K2NbF7 sample was substantiated, with the composite sample being able to desorb hydrogen 30 times faster than did pure LiAlH4. Furthermore, with the presence of 10 wt.% K2NbF7, the calculated activation energy values for the first two desorption stages were significantly reduced to 80 and 86 kJ/mol; 24 and 26 kJ/mol lower than the as-milled LiAlH4. After analysis of the X-ray diffraction result, it is believed that the in situ formation of NbF4, LiF, and K or K-containing phases that appeared during the heating process promoted the amelioration of the desorption behavior of LiAlH4 with the addition of K2NbF7.
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