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  1. Anuar ST, Abdullah NS, Yahya NKEM, Chin TT, Yusof KMKK, Mohamad Y, et al.
    Environ Res, 2023 Mar 23;227:115717.
    PMID: 36963716 DOI: 10.1016/j.envres.2023.115717
    Microplastics (MPs) with the size of 1 μm-5 mm are pollutants of great concern ubiquitously found in the environment. Existing efforts have found that most of the MPs present in the seas mainly originated from land via riverine inputs. Asian rivers are known to be among the top in microplastic emissions. However, field data are scarce, especially in Malaysia. This study presents the distribution and characteristics of MPs in the surface water of two major river basins of Malaysia, namely Langat River (West Coast/Straits of Malacca) and Kelantan River (East Coast/South China Sea). Water samples were collected at 21-22 locations in Kelantan and Langat rivers, covering the river, estuary and sea. MPs were physically classified based on sizes, shapes, colours and surface morphology (SEM-EDS). The average of 179.6 items/L and 1464.8 items/L of MPs had been quantified from Kelantan and Langat rivers, respectively. Fibre (91.90%) was highly recorded at Kelantan, compared to Langat whereby both fibre (59.21%) and fragment (38.87%) were prevalence. Anthropogenic activities and urbanised areas contribute to high microplastic abundance, especially in the Langat River. Micro-FTIR analysis identified 14 polymers in Kelantan River, whereas 20 polymers were found in Langat River. Polypropylene, polyethylene, polyethylene terephthalate, nylon, phenoxy resins, poly(methyl acrylate), poly(methyl methacrylate), polystyrene, polytetrafluoroethylene, polyurethane and rayon were discovered in both rivers, although only polyethylene was significant (>1 ppm) when further analysed using pyrolysis-GC/MS. Correlation analysis and multiple linear regression were used to explain the relationship between water quality and MP abundance, suggesting only turbidity was positively significant to the microplastic occurrence. This comprehensive study is first to suggest a full-scale monitoring protocol for MPs in Malaysian riverine system and is significant in understanding MPs abundance in correlation to in-situ environmental factors. Consequently, this will allow the right authorities to develop mitigation strategies to address riverine plastic pollution in major river basins in Malaysia and the South East Asia.
  2. Verasoundarapandian G, Zakaria NN, Shaharuddin NA, Khalil KA, Puasa NA, Azmi AA, et al.
    Plants (Basel), 2021 Nov 16;10(11).
    PMID: 34834831 DOI: 10.3390/plants10112468
    Oil spill incidents are hazardous and have prolonged damage to the marine environment. Management and spill clean-up procedures are practical and rapid, with several shortcomings. Coco peat (CP) and coco fibre (CF) are refined from coconut waste, and their abundance makes them desirable for diesel spillage treatment. Using a filter-based system, the selectivity of coco peat sorbent was tested using CP, CF and peat-fibre mix (CPM). CP exhibited maximal diesel sorption capacity with minimal seawater uptake, thus being selected for further optimisation analysis. The heat treatment considerably improved the sorption capacity and efficiency of diesel absorbed by CP, as supported by FTIR and VPSEM-EDX analysis. Conventional one-factor-at-a-time (OFAT) examined the performance of diesel sorption by CP under varying parameters, namely temperature, time of heating, packing density and diesel concentration. The significant factors were statistically evaluated using response surface methodology (RSM) via Plackett-Burman design (PB) and central composite design (CCD). Three significant (p < 0.05) factors (time, packing density and diesel concentration) were identified by PB and further analysed for interactions among the parameters. CCD predicted efficiency of diesel absorbed at 59.92% (71.90 mL) (initial diesel concentration of 30% v/v) and the experimental model validated the design with 59.17% (71.00 mL) diesel sorbed at the optimised conditions of 14.1 min of heating (200 °C) with packing density of 0.08 g/cm3 and 30% (v/v) of diesel concentration. The performance of CP in RSM (59.17%) was better than that in OFAT (58.33%). The discoveries imply that natural sorbent materials such as CP in oil spill clean-up operations can be advantageous and environmentally feasible. This study also demonstrated the diesel-filter system as a pilot study for the prospective up-scale application of oil spills.
  3. Ibrahim YS, Tuan Anuar S, Azmi AA, Wan Mohd Khalik WMA, Lehata S, Hamzah SR, et al.
    JGH Open, 2021 Jan;5(1):116-121.
    PMID: 33490620 DOI: 10.1002/jgh3.12457
    Background and Aim: While dietary exposure to microplastics is increasingly recognized, it is unknown if ingested plastics remain within the digestive tract. We aimed to examine human colectomy specimens for microplastics and to report the characteristics as well as polymer composition of the particles.

    Methods: Colectomy samples were obtained from 11 adults (mean age 45.7, six males) who were residents of Northeastern Peninsular Malaysia. Microplastics were identified following chemical digestion of specimens and subsequent filtration. The samples were then examined for characteristics (abundance, length, shape, and color) and composition of three common polymer types using stereo- and Fourier Transform InfraRed (FTIR) microscopes.

    Results: Microplastics were detected in all 11 specimens with an average of 331 particles/individual specimen or 28.1 ± 15.4 particles/g tissue. Filaments or fibers accounted for 96.1% of particles, and 73.1% of all filaments were transparent. Out of 40 random filaments from 10 specimens (one had indeterminate spectra patterns), 90% were polycarbonate, 50% were polyamide, and 40% were polypropylene.

    Conclusion: Our study suggests that microplastics are ubiquitously present in the human colon.

  4. Husnain AU, Mokhtar N, Mohamed Shah NB, Dahari MB, Azmi AA, Iwahashi M
    PLoS One, 2024;19(2):e0296969.
    PMID: 38394180 DOI: 10.1371/journal.pone.0296969
    There are three primary objectives of this work; first: to establish a gas concentration map; second: to estimate the point of emission of the gas; and third: to generate a path from any location to the point of emission for UAVs or UGVs. A mountable array of MOX sensors was developed so that the angles and distances among the sensors, alongside sensors data, were utilized to identify the influx of gas plumes. Gas dispersion experiments under indoor conditions were conducted to train machine learning algorithms to collect data at numerous locations and angles. Taguchi's orthogonal arrays for experiment design were used to identify the gas dispersion locations. For the second objective, the data collected after pre-processing was used to train an off-policy, model-free reinforcement learning agent with a Q-learning policy. After finishing the training from the training data set, Q-learning produces a table called the Q-table. The Q-table contains state-action pairs that generate an autonomous path from any point to the source from the testing dataset. The entire process is carried out in an obstacle-free environment, and the whole scheme is designed to be conducted in three modes: search, track, and localize. The hyperparameter combinations of the RL agent were evaluated through trial-and-error technique and it was found that ε = 0.9, γ = 0.9 and α = 0.9 was the fastest path generating combination that took 1258.88 seconds for training and 6.2 milliseconds for path generation. Out of 31 unseen scenarios, the trained RL agent generated successful paths for all the 31 scenarios, however, the UAV was able to reach successfully on the gas source in 23 scenarios, producing a success rate of 74.19%. The results paved the way for using reinforcement learning techniques to be used as autonomous path generation of unmanned systems alongside the need to explore and improve the accuracy of the reported results as future works.
  5. Tan Sian Hui Abdullah HS, Aqlili Riana Mohd Asseri SN, Khursyiah Wan Mohamad WN, Kan SY, Azmi AA, Yong Julius FS, et al.
    Environ Pollut, 2021 Feb 15;271:116295.
    PMID: 33383429 DOI: 10.1016/j.envpol.2020.116295
    This manuscript describes the reuse of biowaste for the biosynthesis of silver nanoparticles (AgNPs) and their applications. In particular, we hypothesized that the phytochemicals in the onion peels could act as reductant for silver nanoparticles syntheses. AgNO3 solution (1 mmol) was added dropwise to an aqueous solution of onion peel extract in 3:7 ratio. The reaction mixture was subjected to heating at 90 °C for about 30 min. During the synthesis of the AgNPs, the change of the colour of solution was observed. The AgNPs solution was centrifuged to obtain the two layers, which consists of clear solution and solid layers at 12000 rpm for 30 min. The precipitate was filtered and was re-dispersed in deionised water (25 mL). The solution was centrifuged again to obtain the purified AgNPs. Subsequently, this solution was freeze dried for 48 h to afford the powdered AgNPs. In this work, the structure of the AgNPs were synthesized in spherical shape, with an average size of 12.5 nm observed in the Transmission electron microscopy (TEM) analysis. For catalytic application, the synthesized AgNPs could be applied as green catalyst to promote Knoevenagel and Hantzsch reactions. In most cases, the desired products were obtained in satisfactory yields. In addition, the AgNPs were found to be recyclable for the subsequent reactions. After five successive runs, the average isolated yields for both transformations were recorded to be 91% (Knoevenagel condensation) and 94% (Hantzsch reaction), which indicated that the existing AgNPs could apply as green catalyst in the field of organic synthesis. Furthermore, the AgNPs also showed satisfactory result in antioxidant activity. The current results indicate that the AgNPs can act as alternative antioxidant agent and green catalyst in mediating organic transformations.
  6. Zamree ND, Puasa NA, Lim ZS, Wong CY, Shaharuddin NA, Zakaria NN, et al.
    Plants (Basel), 2023 Jul 03;12(13).
    PMID: 37447097 DOI: 10.3390/plants12132536
    Research has confirmed that the utilisation of Antarctic microorganisms, such as bacteria, yeasts and fungi, in the bioremediation of diesel may provide practical alternative approaches. However, to date there has been very little attention towards Antarctic microalgae as potential hydrocarbon degraders. Therefore, this study focused on the utilisation of an Antarctic microalga in the bioremediation of diesel. The studied microalgal strain was originally obtained from a freshwater ecosystem in Paradise Bay, western Antarctic Peninsula. When analysed in systems with and without aeration, this microalgal strain achieved a higher growth rate under aeration. To maintain the growth of this microalga optimally, a conventional one-factor-at a-time (OFAT) analysis was also conducted. Based on the optimized parameters, algal growth and diesel degradation performance was highest at pH 7.5 with 0.5 mg/L NaCl concentration and 0.5 g/L of NaNO3 as a nitrogen source. This currently unidentified microalga flourished in the presence of diesel, with maximum algal cell numbers on day 7 of incubation in the presence of 1% v/v diesel. Chlorophyll a, b and carotenoid contents of the culture were greatest on day 9 of incubation. The diesel degradation achieved was 64.5% of the original concentration after 9 days. Gas chromatography analysis showed the complete mineralisation of C7-C13 hydrocarbon chains. Fourier transform infrared spectroscopy analysis confirmed that strain WCY_AQ5_3 fully degraded the hydrocarbon with bioabsorption of the products. Morphological and molecular analyses suggested that this spherical, single-celled green microalga was a member of the genus Micractinium. The data obtained confirm that this microalga is a suitable candidate for further research into the degradation of diesel in Antarctica.
  7. Chong SY, Azmi AA, Cheah YK
    Data Brief, 2023 Dec;51:109657.
    PMID: 37876741 DOI: 10.1016/j.dib.2023.109657
    Barrientosiimonas humi gen. nov., sp. nov. 39T is a rare actinobacteria strain isolated from the less explored extreme environment of the Antarctic soil. Here, we present the whole genome sequencing and annotation data from the high-quality draft genome of B. humi from Antarctica. The extracted genomic deoxyribonucleic acid (DNA) was sequenced using the PacBio Sequel sequencing platform, followed by the Illumina HiSeq sequencing system. Subsequently, the assembly data from Canu 1.7 and Pilon were subjected to bioinformatics analysis for genome annotation to analyze the entire genomic information of the sequences. Different bioinformatics analysis approaches were used to disclose a high-quality draft genome basis for B. humi and provided a better understanding of its biological and molecular functions. Note that 83,639 reads were predicted from its 3.6Mb genome size, with a guanine-cytosine content (GC) content of 72.39%. The genome was assembled into two contigs, where the larger contig represents the chromosome and the smaller contig represents the plasmid. It is composed of 3,381 coding genes, with about 95% of them being functionally annotated. It consists of 3,318 coding sequences, one tmRNA gene, 57 tRNA genes, and five repeated regions. B. humi was evident, sharing a close sequence similarity with the species Demetria terragena and the family Dermacoccaceae. Gene Ontology (GO) functional classification indicated cell and cell parts were highly represented among the cellular component category; catalytic activity and binding were the most enriched processes within the molecular function category; metabolic and cellular processes were the most represented in the biological process category. Clusters of Orthologous Group (COG) functional classification revealed metabolism-related genes were highly enriched and mostly mapped to amino acid transport metabolism, transcription, energy production, and conversion. Moreover, the Kyoto Encyclopedia of Genes and Genomes (KEGG) functional classification reported that the metabolism process was the most represented KEGG pathway. There were 52 biosynthetic gene clusters involved in secondary metabolites biosynthesis, indicating B. humi has antibacterial, antifungal, cytotoxic, and inhibitor bioactivities. The dataset of the whole-genome sequence of B. humi has been deposited in the European Nucleotide Archive (ENA) repository under the accession number PRJEB44986 / ERP129097. The dataset of the genome annotation of B. humi had been deposited in Zenodo. The reported genomic sequence data for B. humi contributes comprehensive data to the current molecular information of the species, serving as a significant approach that facilitates the advancement of medicine.
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