Displaying publications 21 - 40 of 106 in total

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  1. Fulltext Cognitive impairment and memory dysfunction after a stroke diagnosis: a post-stroke memory assessment
    Al-Qazzaz NK, Ali SH, Ahmad SA, Islam S, Mohamad K
    Neuropsychiatr Dis Treat, 2014;10:1677-91.
    PMID: 25228808 DOI: 10.2147/NDT.S67184
    Cognitive impairment and memory dysfunction following stroke diagnosis are common symptoms that significantly affect the survivors' quality of life. Stroke patients have a high potential to develop dementia within the first year of stroke onset. Currently, efforts are being exerted to assess stroke effects on the brain, particularly in the early stages. Numerous neuropsychological assessments are being used to evaluate and differentiate cognitive impairment and dementia following stroke. This article focuses on the role of available neuropsychological assessments in detection of dementia and memory loss after stroke. This review starts with stroke types and risk factors associated with dementia development, followed by a brief description of stroke diagnosis criteria and the effects of stroke on the brain that lead to cognitive impairment and end with memory loss. This review aims to combine available neuropsychological assessments to develop a post-stroke memory assessment (PSMA) scheme based on the most recognized and available studies. The proposed PSMA is expected to assess different types of memory functionalities that are related to different parts of the brain according to stroke location. An optimal therapeutic program that would help stroke patients enjoy additional years with higher quality of life is presented.
  2. Fulltext A novel DNA nanosensor based on CdSe/ZnS quantum dots and synthesized Fe3O4 magnetic nanoparticles
    Hushiarian R, Yusof NA, Abdullah AH, Ahmad SA, Dutse SW
    Molecules, 2014 Apr 09;19(4):4355-68.
    PMID: 24722589 DOI: 10.3390/molecules19044355
    Although nanoparticle-enhanced biosensors have been extensively researched, few studies have systematically characterized the roles of nanoparticles in enhancing biosensor functionality. This paper describes a successful new method in which DNA binds directly to iron oxide nanoparticles for use in an optical biosensor. A wide variety of nanoparticles with different properties have found broad application in biosensors because their small physical size presents unique chemical, physical, and electronic properties that are different from those of bulk materials. Of all nanoparticles, magnetic nanoparticles are proving to be a versatile tool, an excellent case in point being in DNA bioassays, where magnetic nanoparticles are often used for optimization of the hybridization and separation of target DNA. A critical step in the successful construction of a DNA biosensor is the efficient attachment of biomolecules to the surface of magnetic nanoparticles. To date, most methods of synthesizing these nanoparticles have led to the formation of hydrophobic particles that require additional surface modifications. As a result, the surface to volume ratio decreases and nonspecific bindings may occur so that the sensitivity and efficiency of the device deteriorates. A new method of large-scale synthesis of iron oxide (Fe3O4) nanoparticles which results in the magnetite particles being in aqueous phase, was employed in this study. Small modifications were applied to design an optical DNA nanosensor based on sandwich hybridization. Characterization of the synthesized particles was carried out using a variety of techniques and CdSe/ZnS core-shell quantum dots were used as the reporter markers in a spectrofluorophotometer. We showed conclusively that DNA binds to the surface of ironoxide nanoparticles without further surface modifications and that these magnetic nanoparticles can be efficiently utilized as biomolecule carriers in biosensing devices.
  3. Fulltext Hexavalent molybdenum reduction to mo-blue by a sodium-dodecyl-sulfate-degrading Klebsiella oxytoca strain DRY14
    Halmi MI, Zuhainis SW, Yusof MT, Shaharuddin NA, Helmi W, Shukor Y, et al.
    Biomed Res Int, 2013;2013:384541.
    PMID: 24383052 DOI: 10.1155/2013/384541
    Bacteria with the ability to tolerate, remove, and/or degrade several xenobiotics simultaneously are urgently needed for remediation of polluted sites. A previously isolated bacterium with sodium dodecyl sulfate- (SDS-) degrading capacity was found to be able to reduce molybdenum to the nontoxic molybdenum blue. The optimal pH, carbon source, molybdate concentration, and temperature supporting molybdate reduction were pH 7.0, glucose at 1.5% (w/v), between 25 and 30 mM, and 25°C, respectively. The optimum phosphate concentration for molybdate reduction was 5 mM. The Mo-blue produced exhibits an absorption spectrum with a maximum peak at 865 nm and a shoulder at 700 nm. None of the respiratory inhibitors tested showed any inhibition to the molybdenum-reducing activity suggesting that the electron transport system of this bacterium is not the site of molybdenum reduction. Chromium, cadmium, silver, copper, mercury, and lead caused approximately 77, 65, 77, 89, 80, and 80% inhibition of the molybdenum-reducing activity, respectively. Ferrous and stannous ions markedly increased the activity of molybdenum-reducing activity in this bacterium. The maximum tolerable concentration of SDS as a cocontaminant was 3 g/L. The characteristics of this bacterium make it a suitable candidate for molybdenum bioremediation of sites cocontaminated with detergent pollutant.
  4. Enhanced phenol degradation by immobilized Acinetobacter sp. strain AQ5NOL 1
    Ahmad SA, Shamaan NA, Arif NM, Koon GB, Shukor MY, Syed MA
    World J Microbiol Biotechnol, 2012 Jan;28(1):347-52.
    PMID: 22806810 DOI: 10.1007/s11274-011-0826-z
    A locally isolated Acinetobacter sp. Strain AQ5NOL 1 was encapsulated in gellan gum and its ability to degrade phenol was compared with the free cells. Optimal phenol degradation was achieved at gellan gum concentration of 0.75% (w/v), bead size of 3 mm diameter (estimated surface area of 28.26 mm(2)) and bead number of 300 per 100 ml medium. At phenol concentration of 100 mg l(-1), both free and immobilized bacteria exhibited similar rates of phenol degradation but at higher phenol concentrations, the immobilized bacteria exhibited a higher rate of degradation of phenol. The immobilized cells completely degrade phenol within 108, 216 and 240 h at 1,100, 1,500 and 1,900 mg l(-1) phenol, respectively, whereas free cells took 240 h to completely degrade phenol at 1,100 mg l(-1). However, the free cells were unable to completely degrade phenol at higher concentrations. Overall, the rates of phenol degradation by both immobilized and free bacteria decreased gradually as the phenol concentration was increased. The immobilized cells showed no loss in phenol degrading activity after being used repeatedly for 45 cycles of 18 h cycle. However, phenol degrading activity of the immobilized bacteria experienced 10 and 38% losses after the 46 and 47th cycles, respectively. The study has shown an increased efficiency of phenol degradation when the cells are encapsulated in gellan gum.
  5. Determinants of depression and insomnia among institutionalized elderly people in Malaysia
    Shahar S, Hassan J, Sundar VV, Kong AY, Ping Chin S, Ahmad SA, et al.
    Asian J Psychiatr, 2011 Sep;4(3):188-95.
    PMID: 23051116 DOI: 10.1016/j.ajp.2011.06.001
    Depression and insomnia are common psychiatric disorders among elderly people and reported to be related to several social and health factors. However, their occurrences in relation to food intake have rarely been investigated. Therefore, this study was to identify determinants of depression and insomnia, with emphasised on food intake among 71 elderly people residing in a government funded institution in Malaysia. An interview based questionnaire was used to obtain information on socio-demography, health and functional status, depression, insomnia and food intake. A total of 71.8% subjects had depression and 53% had insomnia. Subjects who had insomnia [Adjusted Odds Ratio (AOR) 19.55, 95% CI=4.04-94.64], needed help/unable to perform >4 items of IADL (AOR=16.65, 95% CI=3.95-70.22), had hypertension (AOR=7.66, 95% CI=1.37-42.76), had >50% wastage of poultry or fish (AOR=3.66, 95% CI=1.06-12.60) and wastage of vegetables (AOR 3.31, 95% CI=1.03-10.60) were more likely to have depression. Subjects who had depression (AOR 19.55, 95% CI=4.04-94.64), needed help/unable to perform >4 items of IADL (AOR 2.97, 95% CI=1.12-7.84), needed help/unable to handle financial matters (AOR 5.01, 95% CI=1.37-18.27) and had >50% wastage of vegetables (AOR 3.91, 95% CI=1.42-10.82) were at a higher risk to develop insomnia. Depression and insomnia affected more than half of the subjects, interrelated, and associated with functional inability, socioeconomic factor and high food wastage of specific foods.
  6. Fulltext Molybdate reduction by Pseudomonas sp. strain DRY2
    Shukor MY, Ahmad SA, Nadzir MM, Abdullah MP, Shamaan NA, Syed MA
    J Appl Microbiol, 2010 Jun;108(6):2050-8.
    PMID: 19968732 DOI: 10.1111/j.1365-2672.2009.04604.x
    To isolate and characterize a potent molybdenum-reducing bacterium.
  7. Fulltext MYNursingHome: A fully-labelled image dataset for indoor object classification
    Ismail A, Ahmad SA, Che Soh A, Hassan MK, Harith HH
    Data Brief, 2020 Oct;32:106268.
    PMID: 32984464 DOI: 10.1016/j.dib.2020.106268
    A fully labelled image dataset serves as a valuable tool for reproducible research inquiries and data processing in various computational areas, such as machine learning, computer vision, artificial intelligence and deep learning. Today's research on ageing is intended to increase awareness on research results and their applications to assist public and private sectors in selecting the right equipments for the elderlies. Many researches related to development of support devices and care equipment had been done to improve the elderly's quality of life. Indoor object detection and classification for autonomous systems require large annotated indoor images for training and testing of smart computer vision applications. This dataset entitled MYNursingHome is an image dataset for commonly used objects surrounding the elderlies in their home cares. Researchers may use this data to build up a recognition aid for the elderlies. This dataset was collected from several nursing homes in Malaysia comprises 37,500 digital images from 25 different indoor object categories including basket bin, bed, bench, cabinet and others.
  8. Fulltext Biochemical Constituent of Ginkgo biloba (Seed) 80% Methanol Extract Inhibits Cholinesterase Enzymes in Javanese Medaka (Oryzias javanicus) Model
    Hassan I, Wan Ibrahim WN, Yusuf FM, Ahmad SA, Ahmad S
    J Toxicol, 2020;2020:8815313.
    PMID: 33029137 DOI: 10.1155/2020/8815313
    Background: Pathophysiological changes leading to the death of nerve cells present in the brain and spinal cord are referred to as neurodegenerative diseases. Presently, treatment of these diseases is not effective and encounters many challenges due to the cost of drug and side effects. Thus, the search for the alternative agents to replace synthetic drugs is in high demand. Therefore, the aim of this study is to evaluate the anticholinesterase properties of Ginkgo biloba seed.

    Methods: The seed was extracted with 80% methanol. Toxicity studies and evaluation of anticholinesterase activities were carried out in adult Javanese medaka (Oryzias javanicus). Phytochemical study to identify the bioactive lead constituents of the crude extract was also carried out using high performance liquid chromatography (HPLC).

    Results: The result shows activities with high significant differences at P < 0.001 between the treated and nontreated groups. A bioactive compound (vitaxin) was identified with the aid of HPLC method.

    Conclusion: The presence of bioactive compound vitaxin is among the major secondary metabolites that contribute to increasing activities of this plant extract. High anticholinesterase activities and low toxicity effect of this plant show its benefit to be used as natural medicine or supplements.

  9. Fulltext Effective production of keratinase by gellan gum-immobilised Alcaligenes sp. AQ05-001 using heavy metal-free and polluted feather wastes as substrates
    Yusuf I, Ahmad SA, Phang LY, Yasid NA, Shukor MY
    3 Biotech, 2019 Jan;9(1):32.
    PMID: 30622870 DOI: 10.1007/s13205-018-1555-x
    The ability of gellan gum-immobilised cells of the heavy metal-tolerant bacterium Alcaligenes sp. AQ05-001 to utilise both heavy metal-free and heavy metal-polluted feathers (HMPFs) as substrates to produce keratinase enzyme was studied. Optimisation of the media pH, incubation temperature and immobilisation parameters (bead size, bead number, gellan gum concentration) was determined for the best possible production of keratinase using the one-factor-at-a-time technique. The results showed that the immobilised cells could tolerate a broader range of heavy metal concentrations and produced higher keratinase activity at a gellan gum concentration of 0.8% (w/v), a bead size of 3 mm, bead number of 250, pH of 8 and temperature of 30 °C. The entrapped bacterium was used repeatedly for ten cycles to produce keratinase using feathers polluted with 25 ppm of Co, Cu and Ag as substrates without the need for desorption. However, its inability to tolerate/utilise feathers polluted with Hg, Pb, and Zn above 5 ppm, and Ag and Cd above 10 ppm resulted in a considerable decrease in keratinase production. Furthermore, the immobilised cells could retain approximately 95% of their keratinase production capacity when 5 ppm of Co, Cu, and Ag, and 10 ppm of As and Cd were used to pollute feathers. When the feathers containing a mixture of Ag, Co, and Cu at 25 ppm each and Hg, Ni, Pb, and Zn at 5 ppm each were used as substrates, the immobilised cells maintained their operational stability and biological activity (keratinase production) at the end of 3rd and 4th cycles, respectively. The study indicates that HMPF can be effectively utilised as a substrate by the immobilised-cell system of Alcaligenes sp. AQ05-001 for the semi-continuous production of keratinase enzyme.
  10. Fulltext 3D Printed Robot Hand Structure Using Four-Bar Linkage Mechanism for Prosthetic Application
    Abdul Wahit MA, Ahmad SA, Marhaban MH, Wada C, Izhar LI
    Sensors (Basel), 2020 Jul 27;20(15).
    PMID: 32727150 DOI: 10.3390/s20154174
    Trans-radial prosthesis is a wearable device that intends to help amputees under the elbow to replace the function of the missing anatomical segment that resembles an actual human hand. However, there are some challenging aspects faced mainly on the robot hand structural design itself. Improvements are needed as this is closely related to structure efficiency. This paper proposes a robot hand structure with improved features (four-bar linkage mechanism) to overcome the deficiency of using the cable-driven actuated mechanism that leads to less structure durability and inaccurate motion range. Our proposed robot hand structure also took into account the existing design problems such as bulky structure, unindividual actuated finger, incomplete fingers and a lack of finger joints compared to the actual finger in its design. This paper presents the improvements achieved by applying the proposed design such as the use of a four-bar linkage mechanism instead of using the cable-driven mechanism, the size of an average human hand, five-fingers with completed joints where each finger is moved by motor individually, joint protection using a mechanical stopper, detachable finger structure from the palm frame, a structure that has sufficient durability for everyday use and an easy to fabricate structure using 3D printing technology. The four-bar linkage mechanism is the use of the solid linkage that connects the actuator with the structure to allow the structure to move. The durability was investigated using static analysis simulation. The structural details and simulation results were validated through motion capture analysis and load test. The motion analyses towards the 3D printed robot structure show 70-98% similar motion range capability to the designed structure in the CAD software, and it can withstand up to 1.6 kg load in the simulation and the real test. The improved robot hand structure with optimum durability for prosthetic uses was successfully developed.
  11. Fulltext Enhanced caffeine degradation by immobilised cells of Leifsonia sp. strain SIU
    Ibrahim S, Shukor MY, Syed MA, Johari WL, Shamaan NA, Sabullah MK, et al.
    J Gen Appl Microbiol, 2016;62(1):18-24.
    PMID: 26923127 DOI: 10.2323/jgam.62.18
    In a previous study, we isolated Leifsonia sp. strain SIU, a new bacterium from agricultured soil. The bacterium was tested for its ability to degrade caffeine. The isolate was encapsulated in gellan gum and its ability to degrade caffeine was compared with the free cells. The optimal caffeine degradation was attained at a gellan gum concentration of 0.75% (w/v), a bead size of 4 mm diameter, and 250 beads per 100 mL of medium. At a caffeine concentration of 0.1 g/L, immobilised cells of the strain SIU degraded caffeine within 9 h, which is faster when compared to the case of free cells, in which it took 12 h to degrade. The immobilised cells degraded caffeine completely within 39 and 78 h at 0.5 and 1.0 g/L, while the free cells took 72 and 148 h at 0.5 and 1.0 g/L, respectively. At higher caffeine concentrations, immobilised cells exhibited a higher caffeine degradation rate. At concentrations of 1.5 and 2.0 g/L, caffeine-degrading activities of both immobilised and free cells were inhibited. The immobilised cells showed no loss in caffeine-degrading activity after being used repeatedly for nine 24-h cycles. The effect of heavy metals on immobilised cells was also tested. This study showed an increase in caffeine degradation efficiency when the cells were encapsulated in gellan gum.
  12. Photoluminescence Investigation of Carrier Localization in Colloidal PbS and PbS/MnS Quantum Dots
    Zaini MS, Liew JYC, Alang Ahmad SA, Mohmad AR, Ahmad Kamarudin M
    ACS Omega, 2020 Dec 08;5(48):30956-30962.
    PMID: 33324803 DOI: 10.1021/acsomega.0c03768
    The existence of surface organic capping ligands on quantum dots (QDs) has limited the potential in QDs emission properties and energy band gap structure alteration as well as the carrier localization. This drawback can be addressed via depositing a thin layer of a semiconductor material on the surface of QDs. Herein, we report on the comparative study for photoluminescent (PL) properties of PbS and PbS/MnS QDs. The carrier localization effect due to the alteration of energy band gap structure and carrier recombination mechanism in the QDs were investigated via PL measurements in a temperature range of 10-300 K with the variation of the excitation power from 10 to 200 mW. For PbS QDs, the gradient of integrated PL intensity (IPL) as a function of excitation power density graph was less than unity. When the MnS shell layer was deposited onto the PbS core, the PL emission exhibited a blue shift, showing dominant carrier recombination. It was also found that the full width half-maximum showed a gradual broadening with the increasing temperature, affirming the electron-phonon interaction.
  13. In vivo and in vitro effects on cholinesterase of blood of Oreochromis mossambicus by copper
    Basirun AA, Ahmad SA, Sabullah MK, Yasid NA, Daud HM, Khalid A, et al.
    3 Biotech, 2019 Feb;9(2):64.
    PMID: 30729088 DOI: 10.1007/s13205-019-1592-0
    The present study is aimed to evaluate the effects of sub-acute toxicity testing of copper sulphate (CuSO4), on behavioural, histological and biochemical changes of the Oreochromis mossambicus (black tilapia) blood tissues. The effects were assessed according to the previous results on sub-acute toxicity test after exposing fish to several concentrations (0.0, 2.5, 5.0, and 10.0 mg/L). The observations of scanning electron microscope, and transmission electron microscope studies revealed severe histopathological changes on the surface and the cellular changes in blood tissues, respectively. The morphological alterations in blood involved irregular structure of red blood cell and blood clot formation. CuSO4 affected the biochemical alteration of the blood cholinesterase also known as serum cholinesterase (ChE). Blood ChE inhibited up to 80% of activity when exposed to 10.0 mg/L CuSO4. The findings from this study can further improve the quality standards of aquaculture industry and the fundamental basis in selecting suitable strains among freshwater fish species to be used as bioindicator.
  14. Fulltext Polymer Pen Lithography-Fabricated DNA Arrays for Highly Sensitive and Selective Detection of Unamplified Ganoderma Boninense DNA
    Rani E, Mohshim SA, Ahmad MZ, Goodacre R, Alang Ahmad SA, Wong LS
    Polymers (Basel), 2019 Mar 25;11(3).
    PMID: 30960545 DOI: 10.3390/polym11030561
    There is an increasing demand for lithography methods to enable the fabrication of diagnostic devices for the biomedical and agri-food sectors. In this regard, scanning probe lithography methods have emerged as a possible approach for this purpose, as they are not only convenient, robust and accessible, but also enable the deposition of "soft" materials such as complex organic molecules and biomolecules. In this report, the use of polymer pen lithography for the fabrication of DNA oligonucleotide arrays is described, together with the application of the arrays for the sensitive and selective detection of Ganoderma boninense, a fungal pathogen of the oil palm. When used in a sandwich assay format with DNA-conjugated gold nanoparticles, this system is able to generate a visually observable result in the presence of the target DNA. This assay is able to detect as little as 30 ng of Ganoderma-derived DNA without any pre-amplification and without the need for specialist laboratory equipment or training.
  15. Fulltext A Review and Bibliometric Analysis on Applications of Microbial Degradation of Hydrocarbon Contaminants in Arctic Marine Environment at Metagenomic and Enzymatic Levels
    Verasoundarapandian G, Wong CY, Shaharuddin NA, Gomez-Fuentes C, Zulkharnain A, Ahmad SA
    Int J Environ Res Public Health, 2021 02 09;18(4).
    PMID: 33572432 DOI: 10.3390/ijerph18041671
    The globe is presently reliant on natural resources, fossil fuels, and crude oil to support the world's energy requirements. Human exploration for oil resources is always associated with irreversible effects. Primary sources of hydrocarbon pollution are instigated through oil exploration, extraction, and transportation in the Arctic region. To address the state of pollution, it is necessary to understand the mechanisms and processes of the bioremediation of hydrocarbons. The application of various microbial communities originated from the Arctic can provide a better interpretation on the mechanisms of specific microbes in the biodegradation process. The composition of oil and consequences of hydrocarbon pollutants to the various marine environments are also discussed in this paper. An overview of emerging trends on literature or research publications published in the last decade was compiled via bibliometric analysis in relation to the topic of interest, which is the microbial community present in the Arctic and Antarctic marine environments. This review also presents the hydrocarbon-degrading microbial community present in the Arctic, biodegradation metabolic pathways (enzymatic level), and capacity of microbial degradation from the perspective of metagenomics. The limitations are stated and recommendations are proposed for future research prospects on biodegradation of oil contaminants by microbial community at the low temperature regions of the Arctic.
  16. Fulltext Research Trends of Biodegradation of Cooking Oil in Antarctica from 2001 to 2021: A Bibliometric Analysis Based on the Scopus Database
    Zahri KNM, Zulkharnain A, Sabri S, Gomez-Fuentes C, Ahmad SA
    Int J Environ Res Public Health, 2021 02 19;18(4).
    PMID: 33669826 DOI: 10.3390/ijerph18042050
    In the present age, environmental pollution is multiplying due to various anthropogenic activities. Pollution from waste cooking oil is one of the main issues facing the current human population. Scientists and researchers are seriously concerned about the oils released from various activities, including the blockage of the urban drainage system and odor issues. In addition, cooking oil is known to be harmful and may have a carcinogenic effect. It was found that current research studies and publications are growing on these topics due to environmental problems. A bibliometric analysis of studies published from 2001 to 2021 on cooking oil degradation was carried out using the Scopus database. Primarily, this analysis identified the reliability of the topic for the present-day and explored the past and present progresses of publications on various aspects, including the contributing countries, journals and keywords co-occurrence. The links and interactions between the selected subjects (journals and keywords) were further visualised using the VOSviewer software. The analysis showed that the productivity of the publications is still developing, with the most contributing country being the United States, followed by China and India with 635, 359 and 320 publications, respectively. From a total of 1915 publications, 85 publications were published in the Journal of Agricultural and Food Chemistry. Meanwhile, the second and third of the most influential journals were Bioresource Technology and Industrial Crops and Products with 76 and 70 total publications, respectively. Most importantly, the co-occurrence of the author's keywords revealed "biodegradation", "bioremediation", "vegetable oil" and "Antarctic" as the popular topics in this study area, especially from 2011 to 2015. In conclusion, this bibliometric analysis on the degradation of cooking oil may serve as guide for future avenues of research in this area of research.
  17. Fulltext Diesel in Antarctica and a Bibliometric Study on Its Indigenous Microorganisms as Remediation Agent
    Wong RR, Lim ZS, Shaharuddin NA, Zulkharnain A, Gomez-Fuentes C, Ahmad SA
    Int J Environ Res Public Health, 2021 02 05;18(4).
    PMID: 33562609 DOI: 10.3390/ijerph18041512
    Diesel acts as a main energy source to complement human activities in Antarctica. However, the increased expedition in Antarctica has threatened the environment as well as its living organisms. While more efforts on the use of renewable energy are being done, most activities in Antarctica still depend heavily on the use of diesel. Diesel contaminants in their natural state are known to be persistent, complex and toxic. The low temperature in Antarctica worsens these issues, making pollutants more significantly toxic to their environment and indigenous organisms. A bibliometric analysis had demonstrated a gradual increase in the number of studies on the microbial hydrocarbon remediation in Antarctica over the year. It was also found that these studies were dominated by those that used bacteria as remediating agents, whereas very little focus was given on fungi and microalgae. This review presents a summary of the collective and past understanding to the current findings of Antarctic microbial enzymatic degradation of hydrocarbons as well as its genotypic adaptation to the extreme low temperature.
  18. Polycyclic Aromatic Hydrocarbons: Occurrence, Electroanalysis, Challenges, and Future Outlooks
    Zainal PNS, Alang Ahmad SA, Abdul Aziz SFN, Rosly NZ
    Crit Rev Anal Chem, 2020 Nov 06.
    PMID: 33155481 DOI: 10.1080/10408347.2020.1839736
    The past several decades have seen increasing concern regarding the wide distribution of polycyclic aromatic hydrocarbons (PAHs) in environmental matrices. Primary toxicological data show PAHs' persistent characteristics and possible toxicity effects. Because of this pressing global issue, electroanalytical methods have been introduced. These methods are effective for PAH determination in environmental waters, even outclassing sophisticated analytical techniques such as chromatography, conventional spectrophotometry, fluorescence, and capillary electrophoresis. Herein, the literature published on PAHs is reviewed and discussed with special regard to PAH occurrence. Moreover, the recent developments in electrochemical sensors for PAH determination and the challenges and future outlooks in this field, are also presented.
  19. Molecular strategies to increase keratinase production in heterologous expression systems for industrial applications
    Yahaya RSR, Normi YM, Phang LY, Ahmad SA, Abdullah JO, Sabri S
    Appl Microbiol Biotechnol, 2021 May;105(10):3955-3969.
    PMID: 33937928 DOI: 10.1007/s00253-021-11321-y
    Keratinase is an important enzyme that can degrade recalcitrant keratinous wastes to form beneficial recyclable keratin hydrolysates. Keratinase is not only important as an alternative to reduce environmental pollution caused by chemical treatments of keratinous wastes, but it also has industrial significance. Currently, the bioproduction of keratinase from native keratinolytic host is considered low, and this hampers large-scale usage of the enzyme. Straightforward approaches of cloning and expression of recombinant keratinases from native keratinolytic host are employed to elevate the amount of keratinase produced. However, this is still insufficient to compensate for the lack of its large-scale production to meet the industrial demands. Hence, this review aimed to highlight the various sources of keratinase and the strategies to increase its production in native keratinolytic hosts. Molecular strategies to increase the production of recombinant keratinase such as plasmid selection, promoter engineering, chromosomal integration, signal peptide and propeptide engineering, codon optimization, and glycoengineering were also described. These mentioned strategies have been utilized in heterologous expression hosts, namely, Escherichia coli, Bacillus sp., and Pichia pastoris, as they are most widely used for the heterologous propagations of keratinases to further intensify the production of recombinant keratinases adapted to better suit the large-scale demand for them. KEY POINTS: • Molecular strategies to enhance keratinase production in heterologous hosts. • Construction of a prominent keratinolytic host from a native strain. • Patent analysis of keratinase production shows rapid high interest in molecular field.
  20. Fulltext The Association of Falls with Instability: An Analysis of Perceptions and Expectations toward the Use of Fall Detection Devices Among Older Adults in Malaysia
    Abdul Rahman K, Ahmad SA, Che Soh A, Ashari A, Wada C, Gopalai AA
    Front Public Health, 2021;9:612538.
    PMID: 33681130 DOI: 10.3389/fpubh.2021.612538
    Background: Falls are a significant incident among older adults affecting one in every three individuals aged 65 and over. Fall risk increases with age and other factors, namely instability. Recent studies on the use of fall detection devices in the Malaysian community are scarce, despite the necessity to use them. Therefore, this study aimed to investigate the association between the prevalence of falls with instability. This study also presents a survey that explores older adults' perceptions and expectations toward fall detection devices. Methods: A cross-sectional survey was conducted involving 336 community-dwelling older adults aged 50 years and older; based on randomly selected participants. Data were analyzed using quantitative descriptive analysis. Chi-square test was conducted to investigate the associations between self-reported falls with instability, demographic and walking characteristics. Additionally, older adults' perceptions and expectations concerning the use of fall detection devices in their daily lives were explored. Results: The prevalence of falls was 28.9%, where one-quarter of older adults fell at least once in the past 6 months. Participants aged 70 years and older have a higher fall percentage than other groups. The prevalence of falls was significantly associated with instability, age, and walking characteristics. Around 70% of the participants reported having instability issues, of which over half of them fell at least once within 6 months. Almost 65% of the participants have a definite interest in using a fall detection device. Survey results revealed that the most expected features for a fall detection device include: user-friendly, followed by affordably priced, and accurate. Conclusions: The prevalence of falls in community-dwelling older adults is significantly associated with instability. Positive perceptions and informative expectations will be used to develop an enhanced fall detection incorporating balance monitoring system. Our findings demonstrate the need to extend the fall detection device features aiming for fall prevention intervention.
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