Displaying publications 2281 - 2300 of 5752 in total

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  1. Seasonal dynamics of phytoplankton community and functional groups in a tropical river
    Haque MA, Jewel MAS, Akhi MM, Atique U, Paul AK, Iqbal S, et al.
    Environ Monit Assess, 2021 Oct 08;193(11):704.
    PMID: 34623504 DOI: 10.1007/s10661-021-09500-5
    Functional classification of phytoplankton could be a valuable tool in water quality monitoring in the eutrophic riverine ecosystems. This study is novel from the Bangladeshi perspective. In this study, phytoplankton cell density and diversity were studied with particular reference to the functional groups (FGs) approach during pre-monsoon, monsoon, and post-monsoon at four sampling stations in Karatoya River, Bangladesh. A total of 54 phytoplankton species were recorded under four classes, viz. Chlorophyceae (21 species) Cyanophyceae (16 species), Bacillariophyceae (15 species), and Euglenophyceae (2 species). A significantly higher total cell density of phytoplankton was detected during the pre-monsoon season (24.20 × 103 cells/l), while the lowest in monsoon (9.43 × 103 cells/l). The Shannon-Wiener diversity index varied significantly (F = 16.109, P = 000), with the highest value recorded during the post-monsoon season. Analysis of similarity (ANOSIM) identified significant variations among the three seasons (P 
  2. An investigation to study the effects of Tai Chi on human gait dynamics using classical machine learning
    Faisal MAA, Chowdhury MEH, Khandakar A, Hossain MS, Alhatou M, Mahmud S, et al.
    Comput Biol Med, 2022 Mar;142:105184.
    PMID: 35016098 DOI: 10.1016/j.compbiomed.2021.105184
    Tai Chi has been proven effective in preventing falls in older adults, improving the joint function of knee osteoarthritis patients, and improving the balance of stroke survivors. However, the effect of Tai Chi on human gait dynamics is still less understood. Studies conducted in this domain only relied on statistical and clinical measurements on the time-series gait data. In recent years machine learning has proven its ability in recognizing complex patterns from time-series data. In this research work, we have evaluated the performance of several machine learning algorithms in classifying the walking gait of Tai Chi masters (people expert on Tai Chi) from the normal subjects. The study is designed in a longitudinal manner where the Tai Chi naive subjects received 6 months of Tai Chi training and the data was recorded during the initial and follow-up sessions. A total of 57 subjects participated in the experiment among which 27 were Tai Chi masters. We have introduced a gender, BMI-based scaling of the features to mitigate their effects from the gait parameters. A hybrid feature ranking technique has also been proposed for selecting the best features for classification. The research reports 88.17% accuracy and 93.10% ROC AUC values from subject-wise 5-fold cross-validation for the Tai Chi masters' vs normal subjects' walking gait classification for the "Single-task" walking scenarios. We have also got fairly good accuracy for the "Dual-task" walking scenarios (82.62% accuracy and 84.11% ROC AUC values). The results indicate that Tai Chi clearly has an effect on the walking gait dynamics. The findings and methodology of this study could provide preliminary guidance for applying machine learning-based approaches to similar gait kinematics analyses.
  3. Fulltext Effects of Tungsten Disulphide Coating on Tapered Microfiber for Relative Humidity Sensing Applications
    Ali N, Azzuhri SR, Johari MAM, Rashid H, Khudus MIMA, Razak MZA, et al.
    Sensors (Basel), 2021 Oct 27;21(21).
    PMID: 34770442 DOI: 10.3390/s21217132
    Tungsten disulphide (WS2) is a two-dimensional transition-metal dichalcogenide material that can be used to improve the sensitivity of a variety of sensing applications. This study investigated the effect of WS2 coating on tapered region microfiber (MF) for relative humidity (RH) sensing applications. The flame brushing technique was used to taper the standard single-mode fiber (SMF) into three different waist diameter sizes of MF 2, 5, and 10 µm, respectively. The MFs were then coated with WS2 via a facile deposition method called the drop-casting technique. Since the MF had a strong evanescent field that allowed fast near-field interaction between the guided light and the environment, depositing WS2 onto the tapered region produced high humidity sensor sensitivity. The experiments were repeated three times to measure the average transmitted power, presenting repeatability and sensing stability. Each MF sample size was tested with varying humidity levels. Furthermore, the coated and non-coated MF performances were compared in the RH range of 45-90% RH at room temperature. It was found that the WS2 coating on 2 µm MF had a high sensitivity of 0.0861 dB/% RH with linearity over 99%. Thus, MF coated with WS2 encourages enhancement in the evanescent field effect in optical fiber humidity sensor applications.
  4. Fulltext Influence of the Degumming Process Parameters on the Formation of Glyceryl Esters and 3-MCPDE in Refined Palm Oil: Optimization and Palm Oil Quality Analyses
    Nidzam MS, Hossain MS, Ismail N, Abdul Latip R, Mohammad Ilias MK, Mobin Siddique MB, et al.
    Foods, 2022 Jan 05;11(1).
    PMID: 35010250 DOI: 10.3390/foods11010124
    The presence of glyceryl esters (GE) and 3-monochloropropane-1,2-diol esters (3-MCPDE) in refined, bleached, and deodorized (RBD) palm oil is severely concerning to the palm oil consumer. In the present study, the influence of the phosphoric acid degumming process on the formation of GE and 3-MCDE and in the RBD palm oil was determined with varying the acid dose (0.03-0.06 wt%), temperature (70-100 °C), and reaction time (15-45 min). The experimental conditions of the acid degumming process were designed following the central composite design of experiments, and they were optimized using Response Surface Methodology (RSM) based on the minimal formation of GE and 3-MCDE in the RBD palm oil. The optimal experimental conditions of the acid degumming process were a reaction time of 30 min, phosphoric acid concentration of 0.06 wt%, and temperature of 90 °C. Under these experimental conditions, the minimal GE and 3-MCDE formation in RBD palm oil were determined to be 0.61 mg/kg and 0.59 mg/kg; respectively. Several analytical methods were employed to determine RBD palm oil quality, including color, phosphorus, free fatty acids (FFAs), peroxide values, and fatty acid properties. It was found that the phosphoric acid degumming of CPO effectively removed the phosphorus and hydroperoxide content without conceding the quality of palm oil.
  5. Fulltext The effect of traditional games intervention programme in the enhancement school-age children's motor skills: a preliminary study
    Md. Alli Gipit @ Charles, Mohamad Razali Abdullah, Norlaila Azura Kosni, Ahmad Bisyri Husin Musawi Maliki, Rabiu Muazu Musa
    Movement Health & Exercise, 2017;6(2):157-169.
    MyJurnal
    The purpose of the current study is to explore the effectiveness of the
    traditional games intervention programme in the enhancement of form one
    school-age children’s motor skills. The quasi-experiment method is applied.
    A total number of 40 Malaysian children with ages ranging from 12 – 14 were
    randomly selected for the study, [boys (n=20) and girls (n=20)]. The children
    went through the traditional games intervention which consisted of
    performing selected traditional games for 60 minutes, three times weekly for
    a period of eight weeks. Motor fitness performance tests were conducted three
    times (pre, mid, and post-test) which included 30-meter sprint test, 505 agility
    test, modified Bass test for dynamic balance and Nelson reaction times test.
    The data were collected and analysed using MANOVA repeated
    measurement. The results show that traditional games intervention was
    effective in the improvement of motor performance [F (8, 29) = 1704.16, p <
    .05]. Follow-up tests also show that the traditional games intervention is a
    factor [F (12,105) =1.99, p < .05] to agility [F (3,36) = .50, p >.05], reaction
    time [F (3,36) = .51, p >.05], speed [F (3,36) = 3.64, p .05]. The result from this initial study demonstrated that
    Malaysian based traditional games could be efficient in improving the motor
    skills of school-age children.
  6. Fulltext Polymethoxyflavones fromNicotiana plumbaginifolia(Solanaceae) Exert Antinociceptive and Neuropharmacological Effects in Mice
    Shajib MS, Rashid RB, Ming LC, Islam S, Sarker MMR, Nahar L, et al.
    Front Pharmacol, 2018;9:85.
    PMID: 29515437 DOI: 10.3389/fphar.2018.00085
    Polymethoxylavones (PMFs) are known to exhibit significant anti-inflammatory and neuroprotective properties.Nicotiana plumbaginifolia, an annual Bangladeshi herb, is rich in polymethoxyflavones that possess significant analgesic and anxiolytic activities. The present study aimed to determine the antinociceptive and neuropharmacological activities of polyoxygenated flavonoids namely- 3,3',5,6,7,8-hexamethoxy-4',5'-methylenedioxyflavone (1), 3,3',4',5',5,6,7,8-octamethoxyflavone (exoticin) (2), 6,7,4',5'-dimethylenedioxy-3,5,3'-trimethoxyflavone (3), and 3,3',4',5,5',8-hexamethoxy-6,7-methylenedioxyflavone (4), isolated and identified fromN. plumbaginifolia. Antinociceptive activity was assessed using the acetic-acid induced writhing, hot plate, tail immersion, formalin and carrageenan-induced paw edema tests, whereas neuropharmacological effects were evaluated in the hole cross, open field and elevated plus maze test. Oral treatment of compounds1,3, and4(12.5-25 mg/kg b.w.) exhibited dose-dependent and significant (p< 0.01) antinociceptive activity in the acetic-acid, formalin, carrageenan, and thermal (hot plate)-induced pain models. The association of ATP-sensitive K+channel and opioid systems in their antinociceptive effect was obvious from the antagonist effect of glibenclamide and naloxone, respectively. These findings suggested central and peripheral antinociceptive activities of the compounds. Compound1,3, and4(12.5 mg/kg b.w.) demonstrated significant (p< 0.05) anxiolytic-like activity in the elevated plus-maze test, while the involvement of GABAAreceptor in the action of compound3and4was evident from the reversal effects of flumazenil. In addition, compounds1and4(12.5-25 mg/kg b.w) exhibited anxiolytic activity without altering the locomotor responses. The present study suggested that the polymethoxyflavones (1-4) fromN. Plumbaginifoliacould be considered as suitable candidates for the development of analgesic and anxiolytic agents.
  7. Local and transboundary factors' impacts on trace gases and aerosol during haze episode in 2015 El Niño in Malaysia
    Samsuddin NAC, Khan MF, Maulud KNA, Hamid AH, Munna FT, Rahim MAA, et al.
    Sci Total Environ, 2018 Jul 15;630:1502-1514.
    PMID: 29554768 DOI: 10.1016/j.scitotenv.2018.02.289
    Southeast Asian haze is a semi-natural phenomenon that chokes the region each year during the dry monsoon season. Smoke-haze episodes caused by the vegetation and peat fires in Indonesia severely affected large parts of Malaysia during the 2015 El Niño phenomenon. This study aimed to evaluate the factors that influenced the concentrations of aerosol and trace gases during the 2015 haze and non-haze period on a semi-urban site in the southern part of Malaysian peninsula that facing Sumatra (Muar, Site A), and on an urban site near to Kuala Lumpur, influenced by the city centre (Cheras, Site B). Local land use data and the cluster of air mass weighted backward trajectory were used to identify the potential factors from local sources and the transboundary region, respectively. The annual median concentrations of PM10 for semi-urban and urban sites were 45.0μg/m3 and 47.0μg/m3, respectively for the study period (Jan-Dec 2015) from the hourly observation dataset. The highest PM10 concentrations during the haze were 358μg/m3 and 415μg/m3 for the two sites, respectively, representing absolutely unhealthy air. However, the trace gases were within the safe threshold. The average concentrations of PM10 and carbon monoxide were two fold higher during the haze than the non-haze episodes on both sites. Nitrogen dioxide was more influenced by haze compared with sulphur dioxide and ozone. The results of the land use change suggest that the local factor can also partially affect the air pollution on the urban area (Site B) but more visible in 2015. The results of the backward trajectory and the wildfire radiative power showed that the smoke-haze episodes that affected Malaysia in 2015 were mainly initiated in the Indonesian Sumatra and Kalimantan regions. This study provides a very useful information towards the impacted region during El Niño haze episode.
  8. Fulltext Evaluating CNC Milling Performance for Machining AISI 316 Stainless Steel with Carbide Cutting Tool Insert
    Equbal A, Equbal MA, Equbal MI, Ravindrannair P, Khan ZA, Badruddin IA, et al.
    Materials (Basel), 2022 Nov 15;15(22).
    PMID: 36431537 DOI: 10.3390/ma15228051
    The present study investigates the CNC milling performance of the machining of AISI 316 stainless steel using a carbide cutting tool insert. Three critical machining parameters, namely cutting speed (v), feed rate (f) and depth of cut (d), each at three levels, are chosen as input machining parameters. The face-centred central composite design (FCCCD) of the experiment is based on response surface methodology (RSM), and machining performances are measured in terms of material removal rate (MRR) and surface roughness (SR). Analysis of variance, response graphs, and three-dimensional surface plots are used to analyse experimental results. Multi-response optimization using the data envelopment analysis based ranking (DEAR) approach is used to find the ideal configuration of the machining parameters for milling AISI 316 SS. The variables v = 220 m/min, f = 0.20 mm/rev and d = 1.2 mm were obtained as the optimal machine parameter setting. Study reveals that MRR is affected dominantly by d followed by v. For SR, f is the dominating factor followed by d. SR is found to be almost unaffected by v. Finally, it is important to state that this work made an attempt to successfully machine AISI 316 SS with a carbide cutting tool insert, to investigate the effect of important machining parameters on MRR and SR and also to optimize the multiple output response using DEAR method.
  9. Fulltext Emotional Intelligence, Depression, Stress and Anxiety Amongst Undergraduate Dental Students During the COVID-19 Pandemic
    Dasor MM, Jafridin AA, Azhar AA, Asma AAA, Manivannan PC, Bilal S, et al.
    Int J Public Health, 2023;68:1604383.
    PMID: 36846156 DOI: 10.3389/ijph.2023.1604383
    Objectives: This study aimed to measure depression, anxiety and stress (DAS) among undergraduate dental students during the COVID-19 pandemic, identify key contributing factors of stress and explore the association of emotional intelligence to DAS. Methods: A multi-centre, cross-sectional study was conducted across four universities in Malaysia. The study administered a questionnaire consisting of the validated Depression Anxiety Stress Scale (DASS), Dental Environment Stress (DES), Emotional Intelligence Scale (EI) and 10 statements assessing COVID-19 specific potential stressor factors. Results: Participants included 791 students across four universities. Abnormal levels of DAS were identified in 60.6%, 66.8% and 42.6% of the study participants, respectively. "Pressure of performance," "Faculty administration" and "Self-efficacy belief" were the highest rated stressors. On-time graduation was the main COVID-19 specific stressor factor. EI was negatively correlated with DAS scores (p < 0.001). Conclusion: The levels of DAS during COVID-19 pandemic in this population is high. However, participants with higher EI presented with lower DAS suggesting that EI may be a form of coping resource and should be enhanced in this population.
  10. Fulltext Evaluation of allelopathic effects of Parthenium hysterophorus L. methanolic extracts on some selected plants and weeds
    Bashar HMK, Juraimi AS, Ahmad-Hamdani MS, Uddin MK, Asib N, Anwar MP, et al.
    PLoS One, 2023;18(1):e0280159.
    PMID: 36608038 DOI: 10.1371/journal.pone.0280159
    Herbicides made from natural molecules are cost-effective and environmentally friendly alternatives to synthetic chemical herbicides for controlling weeds in the crop field. In this context, an investigation was carried out to ascertain the allelopathic potential of Parthenium hysterophorus L. as well as to identify its phenolic components which are responsible for the allelopathic effect. During the observation, the rate of germination and seedlings' growth of Vigna subterranea (L.) Verdc, Raphanus sativus (L.) Domin, Cucurbita maxima Duchesne., Cucumis sativus L., Solanum lycopersicum L., Capsicum frutescens L., Zea mays L., Abelmoschus esculentus (L.) Moench, Daucus carota L., Digitaria sanguinalis (L.) Scop and Eleusine indica (L.) Gaertn were investigated by using methanol extracts, isolated from leaf, stem and flower of P. hysterophorus. Six concentrations (i.e., 25, 50, 75, 100, and 150 g L-1) of methanol extracts were isolated from P. hysterophorus leaf, stem and flower were compared to the control (distilled water). It was also observed that the concentration of methanol extracts (isolated from P. hysterophorus leaf, stem, and flower) while increased, the rate of seed germination and seedling growth of both selected crops and weeds decreased drastically, indicating that these methanol extracts have allelopathic potential. The allelopathic potential of P. hysterophorus leaf extraction (811) was found higher than the extraction of the stem (1554) and flower (1109), which is confirmed by EC50 values. The principal component analysis (PCA) was also used to re-validate the allelopathic potentiality of these methanol extracts and confirmed that Raphanus sativus, Solanum lycopersicum, Capsicum frutescens, Abelmoschus esculentus, Daucus carota, Digitaria sanguinalis, and Eleusine indica were highly susceptible to allelochemicals of P. hysterophorus. Besides these, the LC-MS analysis also revealed that the P. hysterophorus leaf extract contained 7 phenolic compounds which were responsible for the inhibition of tested crops and weeds through allelopathic effect. The results of the current study revealed that the leaf of P. hysterophorus is a major source of allelopathic potential on crops and weeds and which could be used as a valuable natural herbicide in the future for the sustainability of crop production through controlling weeds.
  11. Fulltext A Compact Mu-Near-Zero Metamaterial Integrated Wideband High-Gain MIMO Antenna for 5G New Radio Applications
    Hasan MM, Islam MT, Rahim SKA, Alam T, Rmili H, Alzamil A, et al.
    Materials (Basel), 2023 Feb 20;16(4).
    PMID: 36837381 DOI: 10.3390/ma16041751
    This article demonstrates a compact wideband four-port multiple-input-multiple-output (MIMO) antenna system integrated with a wideband metamaterial (MM) to reach high gain for sub-6 GHz new radio (NR) 5G communication. The four antennas of the proposed MIMO system are orthogonally positioned to the adjacent antennas with a short interelement edge-to-edge distance (0.19λmin at 3.25 GHz), confirming compact size and wideband characteristics 55.2% (3.25-5.6 GHz). Each MIMO system component consists of a fractal slotted unique patch with a transmission feed line and a metal post-encased defected ground structure (DGS). The designed MIMO system is realized on a low-cost FR-4 printed material with a miniature size of 0.65λmin × 0.65λmin × 0.02λmin. A 6 × 6 array of double U-shaped resonator-based unique mu-near-zero (MNZ) wideband metamaterial reflector (MMR) is employed below the MIMO antenna with a 0.14λmin air gap, improving the gain by 2.8 dBi and manipulating the MIMO beam direction by 60°. The designed petite MIMO system with a MM reflector proposes a high peak gain of 7.1 dBi in comparison to recent relevant antennas with high isolation of 35 dB in the n77/n78/n79 bands. In addition, the proposed wideband MMR improves the MIMO diversity and radiation characteristics with an average total efficiency of 68% over the desired bands. The stated MIMO antenna system has an outstanding envelope correlation coefficient (ECC) of <0.045, a greater diversity gain (DG) of near 10 dB (>9.96 dB), a low channel capacity loss (CCL) of <0.35 b/s/Hz and excellent multiplexing efficiency (ME) of higher than -1.4 dB. The proposed MIMO concept is confirmed by fabricating and testing the developed MIMO structure. In contrast to the recent relevant works, the proposed antenna is compact in size, while maintaining high gain and wideband characteristics, with strong MIMO performance. Thus, the proposed concept could be a potential approach to the 5G MIMO antenna system.
  12. Fulltext Dominant phytoplankton groups as the major source of polyunsaturated fatty acids for hilsa (Tenualosa ilisha) in the Meghna estuary Bangladesh
    Shaha DC, Hasan J, Kundu SR, Yusoff FM, Salam MA, Khan M, et al.
    Sci Rep, 2022 Dec 05;12(1):20980.
    PMID: 36470973 DOI: 10.1038/s41598-022-24500-2
    The tropical estuarine ecosystem is fascinating for studying the dynamics of water quality and phytoplankton diversity due to its frequently changing hydrological conditions. Most importantly, phytoplankton is the main supplier of ω3 polyunsaturated fatty acids (PUFA) in the coastal food web for fish as they could not synthesize PUFA. This study evaluated seasonal variations of water quality parameters in the Meghna River estuary (MRE), explored how phytoplankton diversity changes according to hydro-chemical parameters, and identified the major phytoplankton groups as the main source of PUFA for hilsa fish. Ten water quality indicators including temperature, dissolved oxygen, pH, salinity, dissolved inorganic nitrogen (DIN = nitrate, nitrite, ammonia) and phosphorus, dissolved silica and chlorophyll-a were evaluated. In addition, phytoplankton diversity was assessed in the water and hilsa fish gut. Principal component analysis (PCA) was used to analyze the spatio-temporal changes in the water quality conditions, and the driving factors in the MRE. Four main components were extracted and explained 75.4% variability of water quality parameters. The most relevant driving factors were dissolved oxygen, salinity, temperature, and DIN (nitrate, nitrite and ammonia). These variabilities in physicochemical parameters and dissolved inorganic nutrients caused seasonal variations in two major groups of phytoplankton. Peak abundance of Chlorophyta (green algae) occurred in water in nutrient-rich environments (nitrogen and phosphorus) during the wet (36%) season, while Bacillariophyta (diatoms) were dominant during the dry (32%) season that depleted dissolved silica. Thus, the decrease of green algae and the increase of diatoms in the dry season indicated the potential link to seasonal changes of hydro-chemical parameters. The green algae (53.7%) were the dominant phytoplankton group in the hilsa gut content followed by diatoms (22.6%) and both are contributing as the major source of PUFAs for hilsa fish according to the electivity index as they contain the highest amounts of PUFAs (60 and 28% respectively).
  13. Fulltext Acute coronary syndrome in the elderly: the Malaysian National Cardiovascular Disease Database-Acute Coronary Syndrome registry
    Zuhdi AS, Ahmad WA, Zaki RA, Mariapun J, Ali RM, Sari NM, et al.
    Singapore Med J, 2016 Apr;57(4):191-7.
    PMID: 26768171 DOI: 10.11622/smedj.2015145
    The elderly are often underrepresented in clinical trials for acute coronary syndrome (ACS), and cardiologists commonly face management dilemmas in the choice of treatment for this group of patients, particularly concerning the use of invasive revascularisation. This study analysed the characteristics of hospitalised elderly patients with ACS, and compared the outcomes of treatments.
  14. Fulltext Rapid investigation of α-glucosidase inhibitory activity of Phaleria macrocarpa extracts using FTIR-ATR based fingerprinting
    Easmin S, Sarker MZI, Ghafoor K, Ferdosh S, Jaffri J, Ali ME, et al.
    J Food Drug Anal, 2017 Apr;25(2):306-315.
    PMID: 28911672 DOI: 10.1016/j.jfda.2016.09.007
    Phaleria macrocarpa, known as "Mahkota Dewa", is a widely used medicinal plant in Malaysia. This study focused on the characterization of α-glucosidase inhibitory activity of P. macrocarpa extracts using Fourier transform infrared spectroscopy (FTIR)-based metabolomics. P. macrocarpa and its extracts contain thousands of compounds having synergistic effect. Generally, their variability exists, and there are many active components in meager amounts. Thus, the conventional measurement methods of a single component for the quality control are time consuming, laborious, expensive, and unreliable. It is of great interest to develop a rapid prediction method for herbal quality control to investigate the α-glucosidase inhibitory activity of P. macrocarpa by multicomponent analyses. In this study, a rapid and simple analytical method was developed using FTIR spectroscopy-based fingerprinting. A total of 36 extracts of different ethanol concentrations were prepared and tested on inhibitory potential and fingerprinted using FTIR spectroscopy, coupled with chemometrics of orthogonal partial least square (OPLS) at the 4000-400 cm-1 frequency region and resolution of 4 cm-1. The OPLS model generated the highest regression coefficient with R2Y = 0.98 and Q2Y = 0.70, lowest root mean square error estimation = 17.17, and root mean square error of cross validation = 57.29. A five-component (1+4+0) predictive model was build up to correlate FTIR spectra with activity, and the responsible functional groups, such as -CH, -NH, -COOH, and -OH, were identified for the bioactivity. A successful multivariate model was constructed using FTIR-attenuated total reflection as a simple and rapid technique to predict the inhibitory activity.
  15. Vertical distributions of radionuclides along the tourist-attractive Marayon Tong Hill in the Bandarban district of Bangladesh
    Siraz MMM, Roy D, Dewan MJ, Alam MS, A M J, Rashid MB, et al.
    Environ Monit Assess, 2023 Feb 10;195(3):382.
    PMID: 36759352 DOI: 10.1007/s10661-023-10921-7
    This is the first attempt in the world to depict the vertical distribution of radionuclides in the soil samples along several heights (900 feet, 1550 feet, and 1650 feet) of Marayon Tong hill in the Chittagong Hill Tracts, Bandarban by HPGe gamma-ray spectrometry. The average activity concentrations of 232Th, 226Ra, and 40K were found to be 37.15 ± 3.76 Bqkg-1, 19.69 ± 2.15 Bqkg-1, and 347.82 ± 24.50 Bqkg-1, respectively, where in most cases, 232Th exceeded the world average value of 30 Bqkg-1. According to soil characterization, soils ranged from slightly acidic to moderately acidic, with low soluble salts. The radium equivalent activity, outdoor and indoor absorbed dose rate, external and internal hazard indices, external and internal effective dose rates, gamma level index, and excess lifetime cancer risk were evaluated and found to be below the recommended or world average values; but a measurable activity of 137Cs was found at soils collected from ground level and at an altitude of 1550 feet, which possibly arises from the nuclear fallout. The evaluation of cumulative radiation doses to the inhabitants via periodic measurement is recommended due to the elevated levels of 232Th.This pioneering work in mapping the vertical distribution of naturally occurring radioactive materials (NORMs) can be an essential factual baseline data for the scientific community that may be used to evaluate the variation in NORMs in the future, especially after the commissioning of the Rooppur Nuclear Power Plant in Bangladesh in 2024.
  16. A deep neural network-based approach for prediction of mutagenicity of compounds
    Kumar R, Khan FU, Sharma A, Siddiqui MH, Aziz IB, Kamal MA, et al.
    Environ Sci Pollut Res Int, 2021 Sep;28(34):47641-47650.
    PMID: 33895950 DOI: 10.1007/s11356-021-14028-9
    We are exposed to various chemical compounds present in the environment, cosmetics, and drugs almost every day. Mutagenicity is a valuable property that plays a significant role in establishing a chemical compound's safety. Exposure and handling of mutagenic chemicals in the environment pose a high health risk; therefore, identification and screening of these chemicals are essential. Considering the time constraints and the pressure to avoid laboratory animals' use, the shift to alternative methodologies that can establish a rapid and cost-effective detection without undue over-conservation seems critical. In this regard, computational detection and identification of the mutagens in environmental samples like drugs, pesticides, dyes, reagents, wastewater, cosmetics, and other substances is vital. From the last two decades, there have been numerous efforts to develop the prediction models for mutagenicity, and by far, machine learning methods have demonstrated some noteworthy performance and reliability. However, the accuracy of such prediction models has always been one of the major concerns for the researchers working in this area. The mutagenicity prediction models were developed using deep neural network (DNN), support vector machine, k-nearest neighbor, and random forest. The developed classifiers were based on 3039 compounds and validated on 1014 compounds; each of them encoded with 1597 molecular feature vectors. DNN-based prediction model yielded highest prediction accuracy of 92.95% and 83.81% with the training and test data, respectively. The area under the receiver's operating curve and precision-recall curve values were found to be 0.894 and 0.838, respectively. The DNN-based classifier not only fits the data with better performance as compared to traditional machine learning algorithms, viz., support vector machine, k-nearest neighbor, and random forest (with and without feature reduction) but also yields better performance metrics. In current work, we propose a DNN-based model to predict mutagenicity of compounds.
  17. Fulltext Nanometal Dust Explosion in Confined Vessel: Combustion and Kinetic Analysis
    Mohd Mokhtar K, Kasmani RM, Che Hassan CR, Hamid MD, Mohamad Nor MI, Mohd Junaidi MU, et al.
    ACS Omega, 2021 Jul 20;6(28):17831-17838.
    PMID: 34308018 DOI: 10.1021/acsomega.1c00967
    Extensive application of metal powder, particularly in nanosize could potentially lead to catastrophic dust explosion, due to their pyrophoric behavior, ignition sensitivity, and explosivity. To assess the appropriate measures preventing accidental metal dust explosions, it is vital to understand the physicochemical properties of the metal dust and their kinetic mechanism. In this work, explosion severity of aluminum and silver powder, which can be encountered in a passivated emitter and rear contact (PERC) solar cell, was explored in a 0.0012 m3 cylindrical vessel, by varying the particle size and powder concentration. The P max and dP/dt max values of metal powder were demonstrated to increase with decreasing particle size. Additionally, it was found that the explosion severity of silver powder was lower than that of aluminum powder due to the more apparent agglomeration effect of silver particles. The reduction on the specific surface area attributed to the particles' agglomeration affects the oxidation reaction of the metal powder, as illustrated in the thermogravimetric (TG) curves. A sluggish oxidation reaction was demonstrated in the TG curve of silver powder, which is contradicted with aluminum powder. From the X-ray photoelectron spectroscopy (XPS) analysis, it is inferred that silver powder exhibited two reactions in which the dominant reaction produced Ag and the other reaction formed Ag2O. Meanwhile, for aluminum powder, explosion products only comprise Al2O3.
  18. Fulltext Immobilization of heavy metals in tannery sludge by the formation of tobermorite in subcritical water treatment with rice husk silica
    Akter A, Goto M, Megat Mohd Noor MJ, Parvez A, Khanam S, Bakar Siddique MA, et al.
    RSC Adv, 2023 Apr 03;13(16):10610-10620.
    PMID: 37025665 DOI: 10.1039/d3ra00595j
    Tannery sludge, heavy metals (HMs) enriched hazardous solid waste, is produced extensively in many regions of the world. Even though the sludge is hazardous, it can be considered a material resource, if organic matter and HMs in the sludge can be stabilized to minimize its negative environmental impacts. This research aimed to evaluate the efficacy of using subcritical water (SCW) treatment for tannery sludge treatment through immobilization and thus reduction of HMs to mitigate their potential environmental risk and toxicity. HMs in the tannery sludge were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and the average concentration of HMs (mg kg-1) was found in the following decreasing order of Cr (12 950) > Fe (1265) > Cu (76) > Mn (44) > Zn (36) > Pb (14) with very high Cr concentration. The result of toxicity characteristics leaching procedure and sequential extraction procedure tests revealed that the raw tannery sludge leachate contained 11.24 mg L-1 Cr, which classified the raw tannery sludge into a very high-risk category. After SCW treatment, the concentration of Cr in leachate was reduced to 1.6 mg L-1 indicating risk reduction to a low-risk category. The eco-toxicity levels of other HMs also decreased considerably after SCW treatment. X-ray diffractometry (XRD) and scanning electron microscopy (SEM) analysis were employed to identify the effective immobilizing substances formed in the SCW treatment process. The favorable formation of immobilizing orthorhombic tobermorite (Ca5Si6O16(OH)2·4H2O) at 240 °C in the SCW treatment process was confirmed by XRD and SEM analysis. The results confirmed that the formation of 11 Å tobermorite is capable of strongly immobilizing HMs in the SCW treatment process. Further, both orthorhombic 11 Å tobermorite and 9 Å tobermorite were successfully synthesized by SCW treatment on a mixture of tannery sludge including rice husk silica and Ca(OH)2 with water under rather mild conditions. Hence, it can be concluded that SCW treatment of tannery sludge with supplementary silica from rice husk can effectively immobilize the HMs and significantly reduce their environmental risk through tobermorite formation.
  19. Fulltext Development and validation of D-PATH website to improve hypertension management among hypertensive patients in Malaysia
    Ab Hamid MR, Buhari SS, Noor HM, Azizan N', Malek KA, Mohd Asmawi UM, et al.
    Digit Health, 2024;10:20552076241242661.
    PMID: 38596405 DOI: 10.1177/20552076241242661
    OBJECTIVE: This study aimed at developing and validating a web application on hypertension management called the D-PATH website.

    METHODS: The website development involved three stages: content analysis, web development, and validation. The model of Internet Intervention was used to guide the development of the website, in addition to other learning and multimedia theories. The content was developed based on literature reviews and clinical guidelines on hypertension. Then, thirteen experts evaluated the website using Fuzzy Delphi Technique.

    RESULTS: The website was successfully developed and contains six learning units. Thirteen experts rated the website based on content themes, presentation, interactivity, and instructional strategies. All experts reached a consensus that the web is acceptable to be used for nutrition education intervention.

    CONCLUSION: D-PATH is a valid web-based educational tool ready to be used to help disseminate information on dietary and physical activity to manage hypertension. This web application was suitable for sharing information on dietary and physical activity recommendations for hypertension patients.

  20. A pioneering study of the radiological mapping in the world's largest mangrove forest (the Sundarbans) and implications for the public and environment
    Al Mahmud J, Siraz MMM, Alam MS, Dewan MJ, Rashid MB, Khandaker MU, et al.
    Mar Pollut Bull, 2024 May;202:116349.
    PMID: 38604081 DOI: 10.1016/j.marpolbul.2024.116349
    Coastal Mangroves are facing growing threats due to the harmful consequences of human activities. This first-ever detailed study of natural radioactivity in soil samples collected from seven tourist destinations within the Sundarbans, the world's largest mangrove forest, was conducted using HPGe gamma-ray spectrometry. Although the activity levels of 226Ra (11 ± 1-44 ± 4 Bq/kg) and 232Th (13 ± 1-68 ± 6 Bq/kg) generally align with global averages, the concentration of 40K (250 ± 20-630 ± 55 Bq/kg) was observed to surpass the worldwide average primarily due to factors like salinity intrusion, fertilizer application, agricultural runoff, which suggests the potential existence of potassium-rich mineral resources near the study sites. The assessment of the hazard parameters indicates that the majority of these parameters are within the recommended limits. The soil samples do not pose a significant radiological risk to the nearby population. The results of this study can establish important radiological baseline data before the Rooppur Nuclear Power Plant begins operating in Bangladesh.
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