Displaying publications 501 - 520 of 6712 in total

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  1. Masseran N, Mohd Safari MA
    J Environ Manage, 2020 Jun 15;264:110429.
    PMID: 32217317 DOI: 10.1016/j.jenvman.2020.110429
    Intensity-duration-frequency (IDF) curves can serve as useful tools in risk assessment of extreme environmental events. Thus, this study proposes an IDF approach for evaluating the risk of expected occurrences of extreme air pollution as measured by an air pollution index (API). Hourly data of Klang city in Malaysia from 1997 to 2016 are analyzed. For each year, a block maxima size is determined based on four different monsoon seasons. Generalized extreme value (GEV) distribution is used as a model to represent the probabilistic behavior of maximum intensity of the API, which is derived from each block. Based on the GEV model, the IDF curves are developed to estimate the extreme pollution intensities that correspond to various duration hours and return periods. Considering the IDF curves, we found that for any duration hour, the magnitude of pollution intensity tends to be high in parallel with increasing return periods. In fact, a high-intensity pollution event that poses a high risk of affecting the environment is less frequent than low-intensity pollution. In conclusion, the IDF curves provide a good basis for decision makers to assess the expected risk of extreme pollution events in the future.
  2. Ghulam Hasan Abbasi, Javaid Akhtar, Muhammad Anwar-ul-haq, Moazzam Jamil, Shafaqat Ali, Rafiq Ahmad, et al.
    Sains Malaysiana, 2016;45:177-184.
    Effects of NaCl salinity and cadmium on the anti-oxidative activity of enzymes like superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), glutathione reductase (GR) and lipid peroxidation contents; malondialdehyde (MDA) were studied in two maize hybrids of different salt tolerance characteristics. An increase in the amount of lipid peroxidation indicated the oxidative stress induced by NaCl and Cd. The results also depicted that NaCl stress caused an increase in the activities of POD, SOD, CAT, APX and GR while cadmium stress increased the activities of POD, SOD and APX but showed no significant effect on CAT and GR in both the studied hybrids. The combined effect of salinity and cadmium on these parameters was higher than that of sole effect of either NaCl or Cd. It was also found that maize hybrid 26204 had better tolerance against both stresses with strong antioxidant system as compared to that of maize hybrid 8441. A comparison of the antioxidants and lipid peroxidation in two maize hybrids having varying level of NaCl and Cd stress tolerance corroborated the importance of reactive oxygen species (ROS) in defense against abiotic stresses.
  3. Raza MR, Sherazi I, Muhammad Aslam, Ahmad F, Abu Bakar Sulong, Muhamad Norhamidi, et al.
    Sains Malaysiana, 2017;46:285-293.
    316L stainless steel is a common biomedical material. Currently, biomedical parts are produced through powder injection molding (PIM). Carbon control is the most critical in PIM. Improper debinding can significantly change the properties of the final product. In this work, thermal debinding and sintering were performed in two different furnaces (i.e. laboratory and commercially available furnaces) to study the mechanical properties and corrosion resistance. Debounded samples were sintered in different atmospheres. The samples sintered in inert gas showed enhanced mechanical properties compared with wrought 316L stainless steel and higher corrosion rate than those sintered in the vacuum furnace. The densification and tensile strength of the hydrogen sintered samples increased up to 3% and 51%, respectively, compared with those of the vacuum-sintered samples. However, the samples sintered in inert gas also exhibited reduced ductility and corrosion resistance. This finding is attributed to the presence of residual carbon in debonded samples during debinding.
  4. Muhammad Hassyakirin Hasim, Irman Abdul Rahman, Sapizah Rahim, Muhammad Taqiyuddin Mawardi Ayob, Liyana Mohd Ali Napia, Shahidan Radiman
    Sains Malaysiana, 2018;47:1861-1866.
    Praseodymium ion, Pr3+ doped Gd2
    O2
    S nanophosphors were successfully synthesized via gamma irradiation route
    along with the heat treatment. The effect of the gamma irradiation (0-150 kGy) on the structural, morphology and
    photoluminescence properties of Gd2
    O2
    S:Pr3+ were characterized via X-ray diffraction (XRD), field emission scanning
    electron microscope (FESEM) and photoluminescence spectroscopy (PL). The thermal properties of precursor sample
    were tested by the thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The chemical bonding of
    the precursor samples were analyzed by Fourier transform infrared spectroscopy (FT-IR). The XRD result confirmed the
    formation of hexagonal phase of Gd2
    O2
    S:Pr3+ without the presence of any impurities. The FESEM inspection showed the
    non-symmetrical shape of particles transformed into grain-like shape. The optimum photoluminescence (PL) emission
    intensities of Gd2-xO2
    S:xPr3+ occur at 50 kGy dose of gamma irradiation and 2 mol% concentration dopant of Pr3+ ions.
    The spectra under 325 nm UV excitation shows a strong green emission at 515 nm, which match the 3
    P0 → 3
    H4
    transition
    of Pr3+ ions. The Gd2
    O2
    S:Pr3+ nanophosphors possessed many useful approaches in various applications mainly as
    radiation detection and biomedical diagnostic.
  5. Sivapragasam M, Moniruzzaman M, Goto M
    Biotechnol J, 2020 Apr;15(4):e1900073.
    PMID: 31864234 DOI: 10.1002/biot.201900073
    Ionic liquids (ILs), a class of materials with unique physicochemical properties, have been used extensively in the fields of chemical engineering, biotechnology, material sciences, pharmaceutics, and many others. Because ILs are very polar by nature, they can migrate into the environment with the possibility of inclusion in the food chain and bioaccumulation in living organisms. However, the chemical natures of ILs are not quintessentially biocompatible. Therefore, the practical uses of ILs must be preceded by suitable toxicological assessments. Among different methods, the use of microorganisms to evaluate IL toxicity provides many advantages including short generation time, rapid growth, and environmental and industrial relevance. This article reviews the recent research progress on the toxicological properties of ILs toward microorganisms and highlights the computational prediction of various toxicity models.
  6. Shafie MH, Gan CY
    Int J Biol Macromol, 2020 Apr 15;149:835-843.
    PMID: 32027904 DOI: 10.1016/j.ijbiomac.2020.02.013
    The deep eutectic solvents (DESs), which were made from different molar ratios (3:1, 2:1, 1:1, 1:2, 1:3) of choline chloride and citric acid monohydrate, were used as media for the pectic polysaccharide extraction from Averrhoa bilmbi (ABP). The physico-chemical, structural, functional and antioxidant properties of ABP were subsequently determined. The ABP was found to be xylogalacturonan. Moreover, results showed that different structures (i.e. linearity of pectin and branch size) of ABP were obtained, hence, affecting the solubility and functional properties due to the surface availability and steric effect. In addition, when increasing the molar ratio of citric acid monohydrate in DES, lower pH and higher TPC values were observed. These values were correlated with antioxidant activities (i.e. free radical scavenging activity and ferric reducing antioxidant power) of ABP. In conclusion, the molar ratio of the DES components plays an important role in extracting ABP with the aforementioned properties.
  7. Rahim MFA, Payus AO
    Acta Med Indones, 2019 Oct;51(4):344-347.
    PMID: 32041919
    Drug induced cholestatic liver injury can posed a great diagnostic difficulty as a result of its long non-exhaustive list of potential offending causes which can be either prescribed or over-the-counter medications, such as medicinal herbs and remedies. Phaleria macrocarpa, or more commonly known as the 'God's crown' by the local people of South East Asia, is not listed as one of the causes. This medicinal plant extract has been increasingly used for traditional treatment for various ailments. Here, we report a case of a young man who has no known medical illness presented with cholestatic pattern of liver injury which caused by chronic ingestion of Phaleria macrocarpa. The objective of this case report is to share the uncommon side effect of taking this traditional product which may have been under-reported due to the unknown effect.
  8. Munir MA, Badri KH
    J Anal Methods Chem, 2020;2020:5814389.
    PMID: 32377440 DOI: 10.1155/2020/5814389
    Biogenic amines (BA) are chemical compounds formed in foods that contain protein, allowing the foods to undergo a bacterial degradation process. Biogenic amines are labeled as toxic food because its consumption exceeding the FDA regulation (50 mg/kg) can be harmful to humans. Some countries also have regulations that prohibit the consumption of biogenic amines in high concentrations, especially histamine. The chromatography methods generally applied by researchers are liquid chromatography (LC) and gas chromatography (GC), where the use of a derivatization reagent is necessary to increase their sensitivity. This review is based on past and present studies about biogenic amine detection related to food samples. The rationale of this study is also to provide data on the comparison of the analytical approaches between LC and GC methods. Furthermore, the various approaches of biogenic amine determination and the most applied analytical methods have been reviewed.
  9. Masseran N, Safari MAM
    Environ Monit Assess, 2020 Jun 17;192(7):441.
    PMID: 32557137 DOI: 10.1007/s10661-020-08376-1
    Modeling and evaluating the behavior of particulate matter (PM10) is an important step in obtaining valuable information that can serve as a basis for environmental risk management, planning, and controlling the adverse effects of air pollution. This study proposes the use of a Markov chain model as an alternative approach for deriving relevant insights and understanding of PM10 data. Using first- and higher-order Markov chains, we analyzed daily PM10 index data for the city of Klang, Malaysia and found the Markov chain model to fit the PM10 data well. Based on the fitted model, we comprehensively describe the stochastic behaviors in the PM10 index based on the properties of the Markov chain, including its states classification, ergodic properties, long-term behaviors, and mean return times. Overall, this study concludes that the Markov chain model provides a good alternative technique for obtaining valuable information from different perspectives for the analysis of PM10 data.
  10. Naz S, Uroos M, Ayoub M
    ACS Omega, 2021 Nov 02;6(43):29233-29242.
    PMID: 34746611 DOI: 10.1021/acsomega.1c04881
    This work presents a cost-effective approach for processing of renewable carbon-rich biomass using pyridinium-based Lewis acidic ionic liquids (LAILs). Rice husk as carbon-rich lignocellulosic waste was pretreated with a series of neutral and Lewis acidic ionic liquids to yield valuable intermediate platform monosaccharides. Novelty in the work lies in direct conversion of lignocellulosic carbohydrates into reducing sugars without their further conversion into 5-hydroxymethylfurfural or any other platform chemicals that are fermentation inhibitors for bioethanol production. The unconverted cellulose-rich material (CRM) is regenerated as a delignified material by the simultaneous addition of antisolvents. CRM and recovered lignin obtained after pretreatment were analyzed via scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy. The process was optimized with respect to a high yield of platform sugars and the quantity as well as quality of recovered CRM and lignin contents. Various reaction parameters involving the molecular structure of ionic liquids (ILs), Lewis acidic strength of ILs, biomass loading into IL, time, temperature, and biomass particle size were screened thoroughly. From all of the tested ILs, unsymmetrical 3-methylpyridinium IL having N-octyl substitution and chloroaluminate anion showed a greater conversion efficiency at 100 °C for 1.5 h. FTIR and SEM analyses of recovered CRM justify >90% lignin removal from rice husk. From all of the removed lignin, 60 wt % of original lignin content was recovered. The Lewis acidic system possessed recycling ability up to 3 times for subsequent treatment of rice husk without a significant loss of efficiency.
  11. Arumugam M, Tahir M, Praserthdam P
    Chemosphere, 2022 Jan;286(Pt 2):131765.
    PMID: 34371351 DOI: 10.1016/j.chemosphere.2021.131765
    Photocatalytic conversion of carbon dioxide (CO2) into gaseous hydrocarbon fuels is an auspicious way to produce renewable fuels in addition to greenhouse gas emission mitigation. In this work, non-metals (B, O, P, and S) doped graphitic carbon nitride (g-C3N4) was prepared via solid-state polycondensation of urea for photocatalytic CO2 reduction into highly needed methane (CH4) with water under UV light irradiation. The various physicochemical characterization results reveal the successful incorporation of B, O, P, and S elements in the g-C3N4 matrix. The maximum CH4 yield of 55.10 nmol/(mLH2O.gcat) over S-doped g-C3N4 has been obtained for CO2 reduction after 7 h of irradiation. This amount of CH4 production was 1.9, 1.4, 1.7, and 2.4-folds higher than B, O, P and bare g-C3N4 samples. The doping of S did not enlarge the surface area and photon absorption ability of the g-C3N4 sample, but this significant improvement was evidently due to effective charge separation and migration. The observed results imply that the doping of non-metal elements provides improved charge separation and is an effective way to boost photocatalyst performance. This work offers an auspicious approach to design non-metal doped g-C3N4 photocatalysts for renewable fuel production and would be promising for other energy application.
  12. Akram M, Nasar A, Rehman A
    Soc Sci Humanit Open, 2021;4(1):100140.
    PMID: 34927055 DOI: 10.1016/j.ssaho.2021.100140
    The purpose of the study is to explore the shadow economy of violent extremism through charity lenses and factors associated with misuse of charitable giving in a global financial system. It reviews the emergency response situations like COVID-19 when financial needs are urgent with lacked monitoring and control over payment disbursement to vulnerable groups. It highlights several governments' significant steps to counter the illicit finance flow through 'public-face' charity organizations. Descriptive research was used to gather secondary data insights using published reports, articles, news portals, and policy briefs from renowned institutions. The findings depict four factors known as economic and capacity, socio-cultural, politico-legal, and global networks support in misuse of charitable giving to finance violent extremism. This study claims not all charitable giving misused for extremism and violence. However, there is a possibility that extremist groups could take advantage of using humanitarian organizations' face to finance violent extremism. Two possible recommendations have been made to overcome this issue by adopting digital payment mechanisms and community engagement to design and deliver the COVID-19 response recovery programs.
  13. Nasaruddin ML, Tajul Arifin K
    J Fungi (Basel), 2021 Nov 19;7(11).
    PMID: 34829274 DOI: 10.3390/jof7110987
    This scoping review is aimed at the application of the metabolomics platform to dissect key metabolites and their intermediates to observe the regulatory mechanisms of starvation-induced autophagy in Saccharomyces cerevisiae. Four research papers were shortlisted in this review following the inclusion and exclusion criteria. We observed a commonly shared pathway undertaken by S. cerevisiae under nutritional stress. Targeted and untargeted metabolomics was applied in either of these studies using varying platforms resulting in the annotation of several different observable metabolites. We saw a commonly shared pathway undertaken by S. cerevisiae under nutritional stress. Following nitrogen starvation, the concentration of cellular nucleosides was altered as a result of autophagic RNA degradation. Additionally, it is also found that autophagy replenishes amino acid pools to sustain macromolecule synthesis. Furthermore, in glucose starvation, nucleosides were broken down into carbonaceous metabolites that are being funneled into the non-oxidative pentose phosphate pathway. The ribose salvage allows for the survival of starved yeast. Moreover, acute glucose starvation showed autophagy to be involved in maintaining ATP/energy levels. We highlighted the practicality of metabolomics as a tool to better understand the underlying mechanisms involved to maintain homeostasis by recycling degradative products to ensure the survival of S. cerevisiae under starvation. The application of metabolomics has extended the scope of autophagy and provided newer intervention targets against cancer as well as neurodegenerative diseases in which autophagy is implicated.
  14. Khairuddin MAN, Lasekan O
    Foods, 2021 Oct 21;10(11).
    PMID: 34828804 DOI: 10.3390/foods10112523
    In the past decades, food products and beverages made from gluten-free cereals were initially created for certain groups of people who experience gluten-related disorders such as wheat allergies, gluten ataxia, non-celiac gluten sensitivity, and the most well-known, celiac disease. Nowadays, the consumption of gluten-free products is not only restricted to targeted groups, but it has become a food trend for normal consumers, especially in countries such as the UK, the US, and some European countries, who believe that consuming a gluten-free product is a healthier choice compared to normal gluten-containing products. However, some research studies have disapproved of this claim because the currently available gluten-free products in the market are generally known to be lower in proteins, vitamins, and minerals and to contain higher lipids, sugar, and salt compared to their gluten-containing counterparts. The use of other gluten-free cereals such as sorghum, millet, and teff as well as pseudo cereals such as buckwheat and quinoa has gained significant interest in research in terms of their various potential health benefits. Hence, this review highlights the potential health benefits of some gluten-free cereals and pseudo cereals apart from corn and rice in the last decade. The potential health benefits of gluten-free products such as bread, pasta, crackers, and cookies and the health benefits of some other non-alcoholic beverages made from gluten-free cereals and pseudo cereals are reported.
  15. Abdul Majid MH, Ibrahim K
    PLoS One, 2021;16(9):e0257762.
    PMID: 34555115 DOI: 10.1371/journal.pone.0257762
    In data modelling using the composite Pareto distribution, any observations above a particular threshold value are assumed to follow Pareto type distribution, whereas the rest of the observations are assumed to follow a different distribution. This paper proposes on the use of Bayesian approach to the composite Pareto models involving specification of the prior distribution on the proportion of data coming from the Pareto distribution, instead of assuming the prior distribution on the threshold, as often done in the literature. Based on a simulation study, it is found that the parameter estimates determined when using uniform prior on the proportion is less biased as compared to the point estimates determined when using uniform prior on the threshold. Applications on income data and finance are included for illustrative examples.
  16. Awais M, Badruddin N, Drieberg M
    Sensors (Basel), 2017 Aug 31;17(9).
    PMID: 28858220 DOI: 10.3390/s17091991
    Driver drowsiness is a major cause of fatal accidents, injury, and property damage, and has become an area of substantial research attention in recent years. The present study proposes a method to detect drowsiness in drivers which integrates features of electrocardiography (ECG) and electroencephalography (EEG) to improve detection performance. The study measures differences between the alert and drowsy states from physiological data collected from 22 healthy subjects in a driving simulator-based study. A monotonous driving environment is used to induce drowsiness in the participants. Various time and frequency domain feature were extracted from EEG including time domain statistical descriptors, complexity measures and power spectral measures. Features extracted from the ECG signal included heart rate (HR) and heart rate variability (HRV), including low frequency (LF), high frequency (HF) and LF/HF ratio. Furthermore, subjective sleepiness scale is also assessed to study its relationship with drowsiness. We used paired t-tests to select only statistically significant features (p < 0.05), that can differentiate between the alert and drowsy states effectively. Significant features of both modalities (EEG and ECG) are then combined to investigate the improvement in performance using support vector machine (SVM) classifier. The other main contribution of this paper is the study on channel reduction and its impact to the performance of detection. The proposed method demonstrated that combining EEG and ECG has improved the system's performance in discriminating between alert and drowsy states, instead of using them alone. Our channel reduction analysis revealed that an acceptable level of accuracy (80%) could be achieved by combining just two electrodes (one EEG and one ECG), indicating the feasibility of a system with improved wearability compared with existing systems involving many electrodes. Overall, our results demonstrate that the proposed method can be a viable solution for a practical driver drowsiness system that is both accurate and comfortable to wear.
  17. Adom MB, Taher M, Mutalabisin MF, Amri MS, Abdul Kudos MB, Wan Sulaiman MWA, et al.
    Biomed Pharmacother, 2017 Dec;96:348-360.
    PMID: 29028587 DOI: 10.1016/j.biopha.2017.09.152
    The medicinal benefits of Plantago major have been acknowledged around the world for hundreds of years. This plant contains a number of effective chemical constituents including flavonoids, alkaloids, terpenoids, phenolic acid derivatives, iridoid glycosides, fatty acids, polysaccharides and vitamins which contribute to its exerting specific therapeutic effects. Correspondingly, studies have found that Plantago major is effective as a wound healer, as well as an antiulcerative, antidiabetic, antidiarrhoeal, anti-inflammatory, antinociceptive, antibacterial, and antiviral agent. It also combats fatigue and cancer, is an antioxidant and a free radical scavenger. This paper provides a review of the medicinal benefits and chemical constituents of Plantago major published in journals from year 1937 to 2015 which are available from PubMed, ScienceDirect and Google Scholar.
  18. Rahman MT, Karim MM
    Biol Trace Elem Res, 2018 Mar;182(1):1-13.
    PMID: 28585004 DOI: 10.1007/s12011-017-1061-8
    Nutritional immunity describes mechanisms for withholding essential transition metals as well as directing the toxicity of these metals against infectious agents. Zinc is one of these transition elements that are essential for both humans and microbial pathogens. At the same time, Zn can be toxic both for man and microbes if its concentration is higher than the tolerance limit. Therefore a "delicate" balance of Zn must be maintained to keep the immune cells surveilling while making the level of Zn either to starve or to intoxicate the pathogens. On the other hand, the invading pathogens will exploit the host Zn pool for its survival and replication. Apparently, different sets of protein in human and bacteria are involved to maintain their Zn need. Metallothionein (MT)-a group of low molecular weight proteins, is well known for its Zn-binding ability and is expected to play an important role in that Zn balance at the time of active infection. However, the differences in structural, functional, and molecular control of biosynthesis between human and bacterial MT might play an important role to determine the proper use of Zn and the winning side. The current review explains the possible involvement of human and bacterial MT at the time of infection to control and exploit Zn for their need.
  19. Jamil H, Din MFU, Tahir MJ, Saqlain M, Hassan Z, Khan MA, et al.
    PLoS Negl Trop Dis, 2022 Dec;16(12):e0010988.
    PMID: 36480553 DOI: 10.1371/journal.pntd.0010988
    BACKGROUND: Crimean-Congo hemorrhagic fever (CCHF) continues to pose a serious threat to the fragile healthcare system of Pakistan with a continuous increase of morbidity and mortality. The present study aimed to assess the knowledge, attitudes, and practices regarding CCHF among general people who resided in Pakistan.

    METHODS: An online cross-sectional survey design was applied, and a convenience sampling technique was used to recruit 1039 adult people from Pakistan. Data were collected from September 08 to October 12, 2021. The questionnaire consisted of a total of 32 questions in four parts assessing socio-demographics, as well as knowledge, attitudes, and practices regarding CCHF. All statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS), and logistic regression analyses were performed to determine the factors associated with good knowledge, positive attitudes, and good practices.

    RESULTS: Alarmingly, 51.5% of participants heard about CCHF infection before administering the survey. Among these, 20.2%, 33.3%, and 48.2% of the study participants had demonstrated good knowledge, positive attitudes, and good practices, respectively. Binary logistic regression analysis revealed that education and income status had a significant impact on knowledge and attitudes (p<0.05). Similarly, the mean attitude scores differed significantly by age, education, and income status (p<0.05).

    CONCLUSIONS: The findings reflected inadequate levels of knowledge, attitudes, and practices regarding CCHF among general people in Pakistan which may regard as lower than expected. As CCHF is a highly contagious disease, it's urgent to initiate a comprehensive approach to handle the situation before it spreads further in Pakistan.

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