Displaying publications 4021 - 4040 of 8055 in total

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  1. Yap HH, Tan HT, Yahaya AM, Baba R, Loh PY, Chong NL
    PMID: 2098916
    Comparative field efficacy studies of four mosquito coil formulations containing active ingredient of d-allethrin (0.19 or 0.28 w/w) and d-transallethrin (0.12 or 0.16% w/w) and blank coils without active ingredient were carried out in living rooms (mean size 54.1 m3) of residential houses in a squatter area in Butterworth, Malaysia. The major indoor biting mosquitos collected in the test site were that of Culex quinquefasciatus Say (84.7%). Mean percentage reduction of blank coils, coils with 0.19 and 0.28% d-allethrin and coils with 0.12 and 0.16% d-transallethrin were 29.0, 71.7, 70.9, 75.0 and 72.6%, respectively. The use of coils as a mean of personal protection against mosquitos is discussed.
  2. Kumar GS, Mak JW, Lam PL, Tan MA, Lim PK
    PMID: 3129797
    Malarial antibodies in 80 patients were measured using the diffusion-in-gel enzyme linked immunosorbent assay (DIG-ELISA), enzyme-linked immunosorbent assay (ELISA) and the indirect fluorescent antibody (IFA) test. Good correlations were obtained between all three tests in terms of sensitivity and reliability. DIG-ELISA has the advantage of being a rapid diagnostic tool for the detection of malarial antibodies.
  3. Tan SY, Lim CS, Teo SM, Lee SH, Razack A, Loh CS
    Med J Malaysia, 2003 Dec;58(5):769-70.
    PMID: 15190667
    We report here a case of a kidney transplant recipient in whom the ureter was initially implanted into the peritoneum. Excessive ultrafiltration volume and reversal of serum vs dialysate creatinine ratio when the patient was recommenced on continuous ambulatory peritoneal dialysis first suggested the diagnosis which was subsequently confirmed by a plain abdominal x-ray demonstrating placement of ureteric stent in the peritoneum. This rare complication was successfully corrected with surgical re-implantation of ureter into the bladder and 5 years later, the patient remains well with good graft function.
  4. Tan WS, Ong ST, Eshaghi M, Foo SS, Yusoff K
    J Med Virol, 2004 May;73(1):105-12.
    PMID: 15042656
    The nucleocapsid (N) protein of Nipah virus (NiV) can be produced in three Escherichia coli strains [TOP10, BL21(DE3) and SG935] under the control of trc promoter. However, most of the product existed in the form of insoluble inclusion bodies. There was no improvement in the solubility of the product when this protein was placed under the control of T7 promoter. However, the solubility of the N protein was significantly improved by lowering the growth temperature of E. coli BL21(DE3) cell cultures. Solubility analysis of N- and C-terminally deleted mutants revealed that the full-length N protein has the highest solubility. The soluble N protein could be purified efficiently by sucrose gradient centrifugation and nickel affinity chromatography. Electron microscopic analysis of the purified product revealed that the N protein assembled into herringbone-like particles of different lengths. The C-terminal end of the N protein contains the major antigenic region when probed with antisera from humans and pigs infected naturally.
  5. Tan DY, Hair Bejo M, Aini I, Omar AR, Goh YM
    Virus Genes, 2004 Jan;28(1):41-53.
    PMID: 14739650
    Base usage and dinucleotide frequency have been extensively studied in many eukaryotic organisms and bacteria, but not for viruses. In this paper, a comprehensive analysis of these aspects for infectious bursal disease virus (IBDV) was presented. The analysis of base usage indicated that all of the IBDV genes possess equivalent overall nucleotide distributions. However when the base usage at each codon positions was analysed by using cluster analysis, the VP5 open reading frame (ORF) formed a different cluster isolated from the other genes. The unusual base usage of VP5 ORF may indicate that the gene was originated by the virus "overprinting strategy", a strategy in which virus may create novel gene by utilizing the unused reading frames of its existing genes. Meanwhile, the GC content of the IBDV genes and the chicken's coding sequences was comparable; suggesting the virus imitation of the host to increase its translational efficiency. The analysis of dinucleotide frequency indicated that IBDV genome had dinucleotide bias: the frequencies of CpG and TpA were lower and the TpG was higher than the expected. Classical methylation pathway, a process where CpG converted to TpG, may explain the significant correlation between the CpG deficiency and TpG abundance. "Principal component analysis of the dinucleotide frequencies" (DF-PCA) was used to analyse the overall dinucleotide frequencies of IBDV genome. DF-PCA on the hypervariable region and polyprotein (VPX-VP4-VP3) gene showed that the very virulent IBDV (vvIBDV) was segregated from other strains; which meant vvIBDV had a unique dinucleotide pattern. In summary, the study of base usage and dinucleotide frequency had unravelled many overlooked genomic properties of the virus.
  6. Ramanathan K, Ungku Dato OA, Kannan Kutty M, Dutt AK, Balasegaram M, Singh H, et al.
    Dent J Malaysia Singapore, 1969 May;9(1):27-39.
    PMID: 5258332
  7. Othman EQ, Kaur G, Mutee AF, Muhammad TS, Tan ML
    J Clin Lab Anal, 2009;23(4):249-58.
    PMID: 19623642 DOI: 10.1002/jcla.20309
    Autophagy is a protein degradation process within the cell and its deregulation has been linked to various diseases and the formation of cancer. One of the important proteins involved in the autophagy process is microtubule-associated protein 1 light chain 3 (MAP1LC3). The aims of this study were to determine the MAP1LC3A and MAP1LC3B protein expression in both normal and cancer breast tissues and to determine the relationship between the expression of these proteins and type of tissues. Immunohistochemistry assessments were carried out on tissue microarrays consisting of breast tissues. MAP1LC3A expression was detected in 52/56 of normal breast tissue cores and 65/67 of breast cancer tissue cores. MAP1LC3B expression was detected in 55/56 of normal breast tissue cores and 67/67 of breast cancer tissue cores. MAP1LC3A and MAP1LC3B protein are expressed in the majority of normal and cancer breast tissues. A large number of MAP1LC3A and MAP1LC3B positive breast cancer tissues cores have high proportion of stained cells (81-100%) as compared with normal breast tissues. However, a significantly higher number of breast cancer tissues were found to express the MAP1LC3A protein with strong immunoreactivity as compared with the normal tissues, suggesting that MAP1LC3A may play a role in breast cancer development.
  8. Avin FA, Subha B, Tan YS, Braukmann TWA, Vikineswary S, Hebert PDN
    Ecol Evol, 2017 09;7(17):6972-6980.
    PMID: 28904776 DOI: 10.1002/ece3.3049
    DNA barcoding involves the use of one or more short, standardized DNA fragments for the rapid identification of species. A 648-bp segment near the 5' terminus of the mitochondrial cytochrome c oxidase subunit I (COI) gene has been adopted as the universal DNA barcode for members of the animal kingdom, but its utility in mushrooms is complicated by the frequent occurrence of large introns. As a consequence, ITS has been adopted as the standard DNA barcode marker for mushrooms despite several shortcomings. This study employed newly designed primers coupled with cDNA analysis to examine COI sequence diversity in six species of Pleurotus and compared these results with those for ITS. The ability of the COI gene to discriminate six species of Pleurotus, the commonly cultivated oyster mushroom, was examined by analysis of cDNA. The amplification success, sequence variation within and among species, and the ability to design effective primers was tested. We compared ITS sequences to their COI cDNA counterparts for all isolates. ITS discriminated between all six species, but some sequence results were uninterpretable, because of length variation among ITS copies. By comparison, a complete COI sequences were recovered from all but three individuals of Pleurotus giganteus where only the 5' region was obtained. The COI sequences permitted the resolution of all species when partial data was excluded for P. giganteus. Our results suggest that COI can be a useful barcode marker for mushrooms when cDNA analysis is adopted, permitting identifications in cases where ITS cannot be recovered or where it offers higher resolution when fresh tissue is. The suitability of this approach remains to be confirmed for other mushrooms.
  9. Tan CK, Natrah I, Suyub IB, Edward MJ, Kaman N, Samsudin AA
    Microbiologyopen, 2019 05;8(5):e00734.
    PMID: 30353678 DOI: 10.1002/mbo3.734
    AIMS: The aim of this study was to identify and compare the gut microbial community of wild and captive Tor tambroides through 16S rDNA metagenetic sequencing followed by functions prediction.

    METHODS AND RESULTS: The library of 16S rDNA V3-V4 hypervariable regions of gut microbiota was amplified and sequenced using Illumina MiSeq. The sequencing data were analyzed using Quantitative Insights into Microbial Ecology (QIIME) pipeline and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). The most abundant bacterial phyla in both wild and captive T. tambroides were Firmicutes, Proteobacteria, Fusobacteria and Bacteroidetes. Cetobacterium spp., Peptostreptococcaceae family, Bacteroides spp., Phosphate solubilizing bacteria PSB-M-3, and Vibrio spp. were five most abundant OTU in wild T. tambroides as compared to Cetobacterium spp., Citrobacter spp., Aeromonadaceae family, Peptostreptococcaceae family and Turicibacter spp. in captive T. tambroides.

    CONCLUSION: In this study, the specimens of the wild T. tambroides contain more diverse gut microbiota than of the captive ones. The results suggested that Cetobacterium spp. is one of the core microbiota in guts of T. tambroides. Besides, high abundant Bacteroides spp., Citrobacter spp., Turicibacter spp., and Bacillus spp. may provide important functions in T. tambroides guts.

    SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this study provide significant information of T. tambroides gut microbiota for further understanding of their physiological functions including growth and disease resistance.

  10. Lee LS, Goh KM, Chan CS, Annie Tan GY, Yin WF, Chong CS, et al.
    Microbiologyopen, 2018 12;7(6):e00615.
    PMID: 29602271 DOI: 10.1002/mbo3.615
    The ability of thermophilic microorganisms and their enzymes to decompose biomass have attracted attention due to their quick reaction time, thermostability, and decreased risk of contamination. Exploitation of efficient thermostable glycoside hydrolases (GHs) could accelerate the industrialization of biofuels and biochemicals. However, the full spectrum of thermophiles and their enzymes that are important for biomass degradation at high temperatures have not yet been thoroughly studied. We examined a Malaysian Y-shaped Sungai Klah hot spring located within a wooded area. The fallen foliage that formed a thick layer of biomass bed under the heated water of the Y-shaped Sungai Klah hot spring was an ideal environment for the discovery and analysis of microbial biomass decay communities. We sequenced the hypervariable regions of bacterial and archaeal 16S rRNA genes using total community DNA extracted from the hot spring. Data suggested that 25 phyla, 58 classes, 110 orders, 171 families, and 328 genera inhabited this hot spring. Among the detected genera, members of Acidimicrobium, Aeropyrum, Caldilinea, Caldisphaera, Chloracidobacterium, Chloroflexus, Desulfurobacterium, Fervidobacterium, Geobacillus, Meiothermus, Melioribacter, Methanothermococcus, Methanotorris, Roseiflexus, Thermoanaerobacter, Thermoanaerobacterium, Thermoanaerobaculum, and Thermosipho were the main thermophiles containing various GHs that play an important role in cellulose and hemicellulose breakdown. Collectively, the results suggest that the microbial community in this hot spring represents a good source for isolating efficient biomass degrading thermophiles and thermozymes.
  11. Ramasamy R, Tong CK, Yip WK, Vellasamy S, Tan BC, Seow HF
    Cell Prolif, 2012 Apr;45(2):132-9.
    PMID: 22309282 DOI: 10.1111/j.1365-2184.2012.00808.x
    BACKGROUND: Mesenchymal stem cells (MSC) have great potential in regenerative medicine, immunotherapy and gene therapy due to their unique properties of self-renewal, high plasticity, immune modulation and ease for genetic modification. However, production of MSC at sufficient clinical scale remains an issue as in vitro generation of MSC inadequately fulfils the demand with respect to patients.

    OBJECTIVES: This study has aimed to establish optimum conditions to generate and characterize MSC from human umbilical cord (UC-MSC).

    MATERIALS AND METHODS: To optimize MSC population growth, basic fibroblast growth factor (bFGF) was utilized in culture media. Effects of bFGF on expansion kinetics, cell cycle, survival of UC-MSC, cytokine secretion, expression of early stem-cell markers and immunomodulation were investigated.

    RESULTS: bFGF supplementation profoundly enhanced UC-MSC proliferation by reducing population doubling time without altering immunophenotype and immunomodulatory function of UC-MSC. However, cell cycle studies revealed that bFGF drove the cells into the cell cycle, as a higher proportion of cells resided in S phase and progressed into M phase. Consistent with this, bFGF was shown to promote expression of cyclin D proteins and their relevant kinases to drive UC-MSC to transverse cell cycle check points, thus, committing the cells to DNA synthesis. Furthermore, supplementation with bFGF changed the cytokine profiles of the cells and reduced their apoptotic level.

    CONCLUSION: Our study showed that bFGF supplementation of UC-MSC culture enhanced the cells' growth kinetics without compromising their nature.

  12. Goh SSL, Lai PSM, Liew SM, Tan KM, Chung WW, Chua SS
    PLoS One, 2020;15(11):e0242051.
    PMID: 33175871 DOI: 10.1371/journal.pone.0242051
    To date, several medication adherence instruments have been developed and validated worldwide. However, most instruments have only assessed medication adherence from the patient's perspective. The aim was to develop and validate the PATIENT-Medication Adherence Instrument (P-MAI) and the HEALTHCARE PROFESSIONAL-Medication Adherence Instrument (H-MAI) to assess medication adherence from the patient's and healthcare professional (HCP)'s perspectives. The P-MAI-12 and H-MAI-12 were developed using the nominal group technique. The face and content validity was determined by an expert panel and piloted. The initial version of these instruments consisted of 12 items were validated from October-December 2018 at a primary care clinic in Malaysia. Included were patients aged ≥21 years, diagnosed with diabetes mellitus, taking at least one oral hypoglycaemic agent and who could understand English. The HCPs recruited were family medicine specialists or trainees. To assess validity, exploratory factor analysis (EFA) and concurrent validity were performed; internal consistency and test-retest were performed to assess its reliability. A total of 120/158 patients (response rate = 75.9%) and 30/33 HCPs (response rate = 90.9%) agreed to participate. EFA found three problematic items in both instruments, which was then removed. The final version of the P-MAI-9 and the HMAI-9 had 9 items each with two domains (adherence = 2 items and knowledge/belief = 7 items). For concurrent validity, the total score of the P-MAI-9 and the H-MAI-9 were not significantly different (p = 0.091), indicating that medication adherence assessed from both the patient's and HCP's perspectives were similar. Both instruments achieved acceptable internal consistency (Cronbach's α: P-MAI-9 = 0.722; H-MAI-9 = 0.895). For the P-MAI-9, 7/9 items showed no significant difference between test and retest whereas 8/9 items in the H-MAI-9 showed significant difference at test and retest (p>0.05). In conclusion, the P-MAI-9 and H-MAI-9 had low sensitivity and high specificity suggesting that both instruments can be used for identifying patients more likely to be non-adherent to their medications.
  13. Zhao Y, Tan EK, Law HY, Yoon CS, Wong MC, Ng I
    Clin Genet, 2002 Dec;62(6):478-81.
    PMID: 12485197
    We report the prevalence and ethnic differences of autosomal-dominant cerebellar ataxia (ADCA) in Singapore. Amongst 204 patients with ataxia who underwent genetic testing for dentatorubral-pallidoluysian atrophy (DRPLA) and for spinocerebellar ataxias (SCA) 1, 2, 3, 6, 7, 8, 10 and 12, 58 (28.4%) patients from 36 families tested positive. SCA 3 was identified in 31 (53.4%) patients from 15 families, SCA 2 in 17 (29.3%) patients from 12 families and SCA 1 in four (6.9%) patients from four families. Other SCA subtypes were rare. SCA 2 was the only subtype identified amongst ethnic Malay and ethnic Indian families. The estimated prevalence of ADCA in Singaporean families was at least 1 : 27,000. Based on the history and ancestry of Singaporeans, our study supported a founder effect for specific SCA subtypes and the association of ethnicity-specific SCA subtypes. Our findings suggest that SCA 2 is relatively common amongst the Malay race and that priority testing for SCA 3 and SCA 2 for ethnic Chinese, and SCA 2 for ethnic Malay, may be cost effective and relevant for the region.
  14. Goh CH, Ng SC, Kamaruzzaman SB, Chin AV, Tan MP
    Medicine (Baltimore), 2017 Oct;96(42):e8193.
    PMID: 29049203 DOI: 10.1097/MD.0000000000008193
    The aim of this study was to determine the relationship between falls and beat-to-beat blood pressure (BP) variability.Continuous noninvasive BP measurement is as accurate as invasive techniques. We evaluated beat-to-beat supine and standing BP variability (BPV) using time and frequency domain analysis from noninvasive continuous BP recordings.A total of 1218 older adults were selected. Continuous BP recordings obtained were analyzed to determine standard deviation (SD) and root mean square of real variability (RMSRV) for time domain BPV and fast-Fourier transform low frequency (LF), high frequency (HF), total power spectral density (PSD), and LF:HF ratio for frequency domain BPV.Comparisons were performed between 256 (21%) individuals with at least 1 fall in the past 12 months and nonfallers. Fallers were significantly older (P = .007), more likely to be female (P = .006), and required a longer time to complete the Timed-Up and Go test (TUG) and frailty walk test (P ≤ .001). Standing systolic BPV (SBPV) was significantly lower in fallers compared to nonfallers (SBPV-SD, P = .016; SBPV-RMSRV, P = .033; SBPV-LF, P = .003; SBPV-total PSD, P = .012). Nonfallers had significantly higher supine to standing ratio (SSR) for SBPV-SD, SBPV-RMSRV, and SBPV-total PSD (P = .017, P = .013, and P = .009). In multivariate analyses, standing BPV remained significantly lower in fallers compared to nonfallers after adjustment for age, sex, diabetes, frailty walk, and supine systolic BP. The reduction in frequency-domain SSR among fallers was attenuated by supine systolic BP, TUG, and frailty walk.In conclusion, reduced beat-to-beat BPV while standing is independently associated with increased risk of falls. Changes between supine and standing BPV are confounded by supine BP and walking speed.
  15. Tay YL, Amanah A, Adenan MI, Wahab HA, Tan ML
    Sci Rep, 2019 12 24;9(1):19757.
    PMID: 31874991 DOI: 10.1038/s41598-019-56106-6
    Mitragyna speciosa Korth (M. speciosa) has been widely used as a recreational product, however, there are growing concerns on the abuse potentials and toxicity of the plant. Several poisoning and fatal cases involving kratom and mitragynine have been reported but the underlying causes remain unclear. The human ether-a-go-go-related gene 1 (hERG1) encodes the pore-forming subunit underlying cardiac rapidly delayed rectifier potassium current (IKr). Pharmacological blockade of the IKr can cause acquired long QT syndrome, leading to lethal cardiac arrhythmias. This study aims to elucidate the mechanisms of mitragynine-induced inhibition on hERG1a/1b current. Electrophysiology experiments were carried out using Port-a-Patch system. Quantitative RT-PCR, Western blot analysis, immunofluorescence and co-immunoprecipitation methods were used to determine the effects of mitragynine on hERG1a/1b expression and hERG1-cytosolic chaperones interaction. Mitragynine was found to inhibit the IKr current with an IC50 value of 332.70 nM. It causes a significant reduction of the fully-glycosylated (fg) hERG1a protein expression but upregulates both core-glycosylated (cg) expression and hERG1a-Hsp90 complexes, suggesting possible impaired hERG1a trafficking. In conclusion, mitragynine inhibits hERG1a/1b current through direct channel blockade at lower concentration, but at higher concentration, it upregulates the complexation of hERG1a-Hsp90 which may be inhibitory towards channel trafficking.
  16. Lew S, Tan GW, Loh XM, Hew JJ, Ooi KB
    Technol Soc, 2020 Nov;63:101430.
    PMID: 33071395 DOI: 10.1016/j.techsoc.2020.101430
    Given that the mobile wallet has become a disruptive innovation, especially in the Malaysian hospitality industry, this study investigates the adoption of mobile wallet in the hospitality industry among consumers. Different from the extant literature, this study extends the newly proposed mobile technology acceptance model with self-efficacy theory, critical mass theory, and flow theory to explain the behavioural intention to adopt. A self-administered questionnaire was utilised to collect data from mobile wallet users who have used a mobile wallet while dining out in restaurants and cafes. Other than technology self-efficacy and perceived critical mass, mobile usefulness, mobile ease of use, mobile self-efficacy, and perceived enjoyment were discovered to have a positive and significant association with the behavioural intention to adopt mobile wallet in the hospitality industry. The findings also suggested there were interrelationships between the constructs employed. Overall, the extended model was able to explain 61% of the variance in behavioural intention to adopt mobile wallet.
  17. Mai CW, Tan JSH, Koay GWL, Lim LYX
    Pharmacy (Basel), 2020 Sep 13;8(3).
    PMID: 32933158 DOI: 10.3390/pharmacy8030170
    Dietary supplementation is increasingly sought after by consumers looking to meet the demands of a modern lifestyle. Effective supplementation requires knowledge of the purpose and proper use of nutritional supplements. Unverified or inadequate guidance on supplementation can propagate misconceptions and increase undue fears of side effects. Community pharmacists are best placed to guide consumers on nutritional supplement use. In this review, a panel comprised of community pharmacists, pharmacy academia, and dietitians (n = 6) convened to provide an experience- and evidence-based guidance on rational drug use, patient education, and integrated and personalized nutrition care in both community and hospital pharmacy settings. A novel framework to guide community pharmacist-led consultations on supplementation is proposed. The four-step CARE (Categorize, Assess, Recommend, Empower) guide was developed to facilitate and optimize outcomes of pharmacist-led nutritional supplement consultation. Telehealth advancements in the form of digital health applications and personalized nutrigenomic DNA testing support Integrative Nutrition Care, and will further promote appropriate supplementation use to improve overall well-being in the community. Practical implementation of the CARE guide is necessary to ascertain its applicability for optimizing outcomes of pharmacist-led consultation and the recommendation of nutritional supplements.
  18. Wong CL, Yong CY, Ong HK, Ho KL, Tan WS
    Front Vet Sci, 2020;7:477.
    PMID: 32974392 DOI: 10.3389/fvets.2020.00477
    Foot-and-mouth disease (FMD) is a devastating livestock disease caused by foot-and-mouth disease virus (FMDV). Outbreaks of this disease in a country always result in conspicuous economic losses to livestock industry and subsequently lead to serious socioeconomic damages due to the immediate imposition of trade embargo. Rapid and accurate diagnoses are imperative to control this infectious virus. In the current review, enzyme-linked immunosorbent assay (ELISA)-based methods used in FMD diagnosis are extensively reviewed, particularly the sandwich, liquid-phase blocking, and solid-phase competition ELISA. The differentiation of infected animals from vaccinated animals using ELISA-based methods is also highlighted, in which the role of 3ABC polyprotein as a marker is reviewed intensively. Recently, more studies are focusing on the molecular diagnostic methods, which detect the viral nucleic acids based on reverse transcription-polymerase chain reaction (RT-PCR) and RT-loop-mediated isothermal amplification (RT-LAMP). These methods are generally more sensitive because of their ability to amplify a minute amount of the viral nucleic acids. In this digital era, the RT-PCR and RT-LAMP are progressing toward the mobile versions, aiming for on-site FMDV diagnosis. Apart from RT-PCR and RT-LAMP, another diagnostic assay specifically designed for on-site diagnosis is the lateral flow immunochromatographic test strips. These test strips have some distinct advantages over other diagnostic methods, whereby the assay often does not require the aid of an external device, which greatly lowers the cost per test. In addition, the on-site diagnostic test can be easily performed by untrained personnel including farmers, and the results can be obtained in a few minutes. Lastly, the use of FMDV diagnostic assays for progressive control of the disease is also discussed critically.
  19. Groth I, Tan GYA, González JM, Laiz L, Carlsohn MR, Schütze B, et al.
    Int J Syst Evol Microbiol, 2007 Mar;57(Pt 3):513-519.
    PMID: 17329776 DOI: 10.1099/ijs.0.64602-0
    The taxonomic status of two actinomycetes isolated from the wall of a hypogean Roman catacomb was established based on a polyphasic investigation. The organisms were found to have chemical and morphological markers typical of members of the genus Amycolatopsis. They also shared a range of chemical, molecular and phenotypic markers which served to separate them from representatives of recognized Amycolatopsis species. The new isolates formed a branch in the Amycolatopsis 16S rRNA gene sequence tree with Amycolatopsis minnesotensis NRRL B-24435(T), but this association was not supported by a particularly high bootstrap value or by the product of the maximum-parsimony tree-making algorithm. The organisms were distinguished readily from closely related Amycolatopsis species based on a combination of phenotypic properties and from all Amycolatopsis strains by their characteristic menaquinone profiles, in which tetra-hydrogenated menaquinones with 11 isoprene units predominated. The combined genotypic and phenotypic data indicate that the isolates merit recognition as representing a novel species of the genus Amycolatopsis. The name proposed for this novel species is Amycolatopsis nigrescens sp. nov., with type strain CSC17Ta-90(T) (=HKI 0330(T)=DSM 44992(T)=NRRL B-24473(T)).
  20. Quah RV, Tan YH, Mubarak NM, Kansedo J, Khalid M, Abdullah EC, et al.
    Waste Manag, 2020 Dec;118:626-636.
    PMID: 33011540 DOI: 10.1016/j.wasman.2020.09.016
    Due to its environment-friendly and replenishable characteristics, biodiesel has the potential to substitute fossil fuels as an alternative source of energy. Although biodiesel has many benefits to offer, manufacturing biodiesel on an industrial scale is uneconomical as a high cost of feedstock is required. A novel sulfonated and magnetic catalyst synthesised from a palm kernel shell (PMB-SO3H) was first introduced in this study for methyl ester or biodiesel production to reduce capital costs. The wasted palm kernel shell (PKS) biochar impregnated with ferrite Fe3O4 was synthesised with concentrated sulphuric acid through the sulfonation process. The SEM, EDX, FTIR, VSM and TGA characterization of the catalysts were presented. Then, the optimisation of biodiesel synthesis was catalysed by PMB-SO3H via the Response Surface Methodology (RSM). It was found that the maximum biodiesel yield of 90.2% was achieved under these optimum operating conditions: 65 °C, 102 min, methanol to oil ratio of 13:1 and the catalyst loading of 3.66 wt%. Overall, PMB-SO3H demonstrated acceptable catalysing capability on its first cycle, which subsequently showed a reduction of the reusability performance after 4 cycles. An important practical implication is that PMB-SO3H can be established as a promising heterogeneous catalyst by incorporating an iron layer which can substantially improve the catalyst separation performance in biodiesel production.
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