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  1. Ling JG, Mansor MH, Abdul Murad AM, Mohd Khalid R, Quay DHX, Winkler M, et al.
    J Biotechnol, 2020 Jan 10;307:55-62.
    PMID: 31545972 DOI: 10.1016/j.jbiotec.2019.09.008
    Carboxylic acid reductases (CARs) are attracting burgeoning attention as biocatalysts for organic synthesis of aldehydes and their follow-up products from economic carboxylic acid precursors. The CAR enzyme class as a whole, however, is still poorly understood. To date, relatively few CAR sequences have been reported, especially from fungal sources. Here, we sought to increase the diversity of the CAR enzyme class. Six new CAR sequences from the white-rot fungus Pycnoporus cinnabarinus were identified from genome-wide mining. Genome and gene clustering analysis suggests that these PcCAR enzymes play different natural roles in Basidiomycete systems, compared to their type II Ascomycete counterparts. The cDNA sequences of all six Pccar genes were deduced and analysis of their corresponding amino acid sequence showed that they encode for proteins of similar properties that possess a conserved modular functional tri-domain arrangement. Phylogenetic analyses showed that all PcCAR enzymes cluster together with the other type IV CARs. One candidate, PcCAR4, was cloned and over-expressed recombinantly in Escherichia coli. Subsequent biotransformation-based screening with a panel of structurally-diverse carboxylic acid substrates suggest that PcCAR4 possessed a more pronounced substrate specificity compared to previously reported CARs, preferring to reduce sterically-rigid carboxylic acids such as benzoic acid. These findings thus present a new functionally-distinct member of the CAR enzyme class.
  2. Khalid R, Nawawi MK, Kawsar LA, Ghani NA, Kamil AA, Mustafa A
    PLoS One, 2013;8(4):e58402.
    PMID: 23560037 DOI: 10.1371/journal.pone.0058402
    M/G/C/C state dependent queuing networks consider service rates as a function of the number of residing entities (e.g., pedestrians, vehicles, and products). However, modeling such dynamic rates is not supported in modern Discrete Simulation System (DES) software. We designed an approach to cater this limitation and used it to construct the M/G/C/C state-dependent queuing model in Arena software. Using the model, we have evaluated and analyzed the impacts of various arrival rates to the throughput, the blocking probability, the expected service time and the expected number of entities in a complex network topology. Results indicated that there is a range of arrival rates for each network where the simulation results fluctuate drastically across replications and this causes the simulation results and analytical results exhibit discrepancies. Detail results that show how tally the simulation results and the analytical results in both abstract and graphical forms and some scientific justifications for these have been documented and discussed.
  3. Jabit ML, Khalid R, Abas F, Shaari K, Hui LS, Stanslas J, et al.
    Z Naturforsch C J Biosci, 2008 2 16;62(11-12):786-92.
    PMID: 18274278
    Two new xanthones, characterized as 4-(1,1-dimethylprop-2-enyl)-1,3,5,8-tetrahydroxyxanthone (1) and penangianaxanthone (2), with three known xanthones, cudratricusxanthone H (3), macluraxanthone C (4) and gerontoxanthone C (5), as well as friedelin and stigmasterol were isolated from the leaves of Garcinia penangiana. Their structures were elucidated by analysis of spectroscopic data and comparison of the NMR data with the literature ones. Significant cytotoxicity against DU-145, MCF-7 and NCI-H460 cancer cell lines was demonstrated by compounds 1-5, with IC50 values ranging from 3.5 to 72.8 microM.
  4. Shahimi S, Lamri MF, Abd Mutalib S, Mohd Khalid R, Md Tab M, Khairuddin F
    Food Chem, 2021 Sep 01;355:129586.
    PMID: 33773458 DOI: 10.1016/j.foodchem.2021.129586
    In order to invent a porcine gelatine detection device using microbial resources, bacterial enzymes with a preference towards porcine gelatine and their candidate genes were evaluated. Five (n = 5) bacterial strains isolated from hot spring water and wet clay, Malaysia were screened for their gelatinase activity. The gelatinase enzyme was extracted and purified using ammonium sulphate precipitation prior to performing gelatinase assay on porcine, bovine and fish gelatine medium substrates. The G2 strain or Enterobacter aerogenes (Strain EA1) was selected for whole genome sequenced after showing a consistent trend of preference towards porcine gelatine. The gelatinase candidate gene gelEA1_9 was cloned and expressed. Based on one-way analysis of variance (ANOVA) with POST-HOC Duncan test (α = 0.05), the final product of gelEA1_9 was identified as a novel gelatinase. This gelatinase presented no significant difference in activity towards porcine gelatine. Hence, the present study demonstrated an enzyme-substrate interaction for porcine gelatine identification.
  5. Ullah S, Khalid R, Rehman MF, Irfan MI, Abbas A, Alhoshani A, et al.
    Front Chem, 2023;11:1202252.
    PMID: 37324561 DOI: 10.3389/fchem.2023.1202252
    The green synthesis of nanomaterials is of utmost interest as it offers an eco-friendly approach over chemical synthetic routes. However, the reported biosynthesis methods are often time-consuming and require heating or mechanical stirring. The current study reports a facile one-pot biosynthesis of silver nanoparticles (AgNPs) mediated by olive fruit extract (OFE) and sunlight irradiation of only 20 s. OFE acts as both a reducing and a capping agent for the formation of OFE-capped AgNPs (AgNPs@OFE). The as-synthesized NPs were systematically characterized by UV-vis spectrometry, Fourier transform infrared (FTIR) spectroscopy, scanning electrochemical microscopy with energy-dispersive X-ray (SEM-EDX), X-ray diffraction (XRD), dynamic light scattering (DLS), and cyclic voltammetry. SEM images confirmed the successful formation of monodispersed spherical AgNPs@OFE of approximately 77 nm. FTIR spectroscopy suggested the involvement of functional groups of phytochemicals from the OFE in the capping and reduction of Ag+ to Ag. The particles revealed excellent colloidal stability as evidenced from the high zeta potential (ZP) value (-40 mV). Interestingly, using the disk diffusion method, AgNPs@OFE revealed higher inhibition efficiency against Gram-negative bacteria (Escherichia coli, Klebsiella oxytoca, and extensively drug-resistant (XDR) Salmonella typhi) than Gram-positive bacteria (Staphylococcus aureus), with Escherichia coli showing the highest inhibition zone of 27 mm. In addition, AgNPs@OFE exhibited maximum potent antioxidant scavenging potential against H2O2, followed by DPPH, O2 -, and OH- free radicals. Overall, OFE can be considered an effective source for the sustainable production of stable AgNPs with potential antioxidant and antibacterial activities for biomedical applications.
  6. Sarfraz M, Raza M, Khalid R, Ivascu L, Albasher G, Ozturk I
    Front Psychol, 2022;13:784773.
    PMID: 35295379 DOI: 10.3389/fpsyg.2022.784773
    Coronavirus disease 2019 (COVID-19) pandemic is continuing to have severe effects on tourism-related industries, as safety precautions have become essential to follow. Based on this, this study aims to explore the role of perceptions of the tourist of safety in tourism destination choice with the mediating effect of tourist trust (TT) in the context of the Chinese tourism sector. In addition, this study considers improvements to safety measures for sustainable tourism and the benefits of the technology transformation in the travel industry because of COVID-19. For this study, a quantitative approach was used, and data were collected through convenient sampling. The questionnaire was measured on a 5-point Likert scale, and a cross-sectional approach was adopted for data analysis. The findings of this study show that the effect of the perceived safety of the social environment, perceived safety of facility and equipment elements, perceived safety of human elements, perceived safety of management elements, and perceived safety of natural environments is significant and positive on the tourist destination choice (TDC). In addition, TT is a significant mediator between these elements and TDC. Furthermore, this study concluded that COVID-19 had increased travel anxiety, with particularly negative effects on the Chinese tourism sector, but that the adoption of perceived safety measures could be beneficial in regaining TT for traveling, eventually giving tourists confidence in choosing their traveling destination.
  7. Linfang Z, Khalid R, Raza M, Chanrawang N, Parveen R
    Front Psychol, 2021;12:796272.
    PMID: 35002890 DOI: 10.3389/fpsyg.2021.796272
    The worth of women's entrepreneurship is accepted globally, but there is less focus on it in developing countries, and societal expectations mean women often lack the confidence to start their own business. The core purpose of this research is to investigate the influence of personality traits on women's inclination toward entrepreneurship. The personality traits are measured through the dimensions of openness, neuroticism, extraversion, conscientiousness, and agreeableness. Further, the study introduced the mediator of self-leadership on personality traits and entrepreneurial intentions of women. The study is quantitative in nature and used a questionnaire survey to collect the data by convenience sampling technique. The data was collected in the context of Pakistan, and Smart PLS was chosen for further analysis. The findings revealed the significance of the relationship between personality traits and entrepreneurial intention. Furthermore, the study also highlighted the significance of self-leadership as a mediator and proposed significant relationships. The study suggested that personality issues should be considered and used from a business perspective, and self-leadership is important for women. The study provides room for policymakers and institutes to inform educational policies to motivate women entrepreneurs for the future.
  8. Zhang J, Raza M, Khalid R, Parveen R, Ramírez-Asís EH
    Ann Oper Res, 2021 Nov 06.
    PMID: 34776572 DOI: 10.1007/s10479-021-04334-3
    There has been substantial research on megaprojects in project management literature. However, there is dearth of studies empirically investigating performance of new launched megaproject of Thailand that named as "Phuket sandbox". The core purpose of this project is to normalize covid-19 situation and resuming tourism in Thailand. Therefore, the evaluation of project performance is essential to achieve the targeted goal for success. The purpose of this study is to investigate the factors that affect project performance (Phuket sandbox) in Thailand. This study used quantitative approach based on structured questionnaire and the data was collected from Phuket, Thailand. The survey conducted from team members which are tourism stake holders' team, immigration team and public service teams including hospitals and hotels who were supposed for the management of Phuket tourism sandbox operations. The study got 222 valid responses only as the members were so busy and partial lockdowns in Thailand hindered the data collection process. The proposed hypothetical model tested by partial least square structural equation modelling. The results of the study found mix findings. The independent variables are team knowledge management, interpersonal conflict, organizational trust, and as significant and dependent variable as project performance through the mediation of psychological capital. The all relationships found to be significant except problem solving competence which have insignificant relationship with project performance as well as problem solving competence and organizational trust have insignificant relation with psychological capital.
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