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Molecular cloning and ontogenic mRNA expression of fatty acid desaturase in the carnivorous striped snakehead fish (Channa striata)

Jaya-Ram A, Ishak SD, Enyu YL, Kuah MK, Wong KL, Shu-Chien AC

Comp Biochem Physiol A Mol Integr Physiol, 2011 Apr;158(4):415-22.
PMID: 21130179 DOI: 10.1016/j.cbpa.2010.11.018

There is very little information on the capacity of freshwater carnivorous fish to biosynthesize highly unsaturated fatty acids (HUFA). The striped snakehead fish (Channa striata) is a carnivorous species cultured inland of several Southeast Asian countries due to its pharmaceutical properties in wound healing enhancement. We described here the full-length cDNA cloning of a striped snakehead fatty acid desaturase (fads), which is responsible for desaturation of unsaturated fatty acids in the HUFA biosynthesis. Bioinformatics analysis reveals a protein coding region with length of 445 amino acids containing all characteristic features of desaturase enzyme, including a cytochrome b5-domain with the heme-binding motif, two transmembrane domains and three histidine-rich regions. The striped snakehead fads amino acid sequence shares high similarity with known fads of other teleosts. The mRNA expression of striped snakehead fads also showed an ontogenic-related increase in expression in 0-20 days after hatch larva. Using ISH, we localized the presence of fads in larva brain, liver and intestinal tissues.
Masking and misleading: concomitant actinomycosis and B-cell lymphoma - a case report and review of literature

Lim JA, Wong PS, Leong KN, Wong KL, Chow TS

Scott Med J, 2018 Aug 30.
PMID: 30165794 DOI: 10.1177/0036933018789312

We report a 72-year-old patient who presented with an ulcerated palatal mass, weight loss and adrenal insufficiency. Repeated biopsies from the mass revealed actinomycosis with no features of malignancy, while computed tomography scanning revealed a left maxillary sinus mass with invasive features and bilateral large adrenal masses. Blood and urine investigations showed adrenal insufficiency. The patient was treated as actinomycosis with adrenal involvement and was given intravenous penicillin and intravenous hydrocortisone. However, his condition did not improve and new signs appeared, that of left facial swelling and lymphadenopathy. A repeat biopsy of the palatal and adrenal masses revealed B-cell lymphoma. This case highlights the possibility that actinomycosis and lymphoma may share similar clinical presentations and may coexist. Either may mask and/or mimic the other, thus causing a delay in diagnosis. We describe the clinical progress and review the related literature. Interestingly, 9 out of the 12 reported cases of concomitant actinomycosis and malignancy (including this case) involve haematological malignancy. A high index of suspicion and treatment response reassessment is important in the management of either rare clinical entity.
Fulltext Diaporthe species causing stem gray blight of red-fleshed dragon fruit (Hylocereus polyrhizus) in Malaysia

Huda-Shakirah AR, Kee YJ, Wong KL, Zakaria L, Mohd MH

Sci Rep, 2021 02 16;11(1):3907.
PMID: 33594187 DOI: 10.1038/s41598-021-83551-z

This study aimed to characterize the new fungal disease on the stem of red-fleshed dragon fruit (Hylocereus polyrhizus) in Malaysia, which is known as gray blight through morphological, molecular and pathogenicity analyses. Nine fungal isolates were isolated from nine blighted stems of H. polyrhizus. Based on morphological characteristics, DNA sequences and phylogeny (ITS, TEF1-α, and β-tubulin), the fungal isolates were identified as Diaporthe arecae, D. eugeniae, D. hongkongensis, D. phaseolorum, and D. tectonendophytica. Six isolates recovered from the Cameron Highlands, Pahang belonged to D. eugeniae (DF1 and DF3), D. hongkongensis (DF9), D. phaseolorum (DF2 and DF12), and D. tectonendophytica (DF7), whereas three isolates from Bukit Kor, Terengganu were recognized as D. arecae (DFP3), D. eugeniae (DFP4), and D. tectonendophytica (DFP2). Diaporthe eugeniae and D. tectonendophytica were found in both Pahang and Terengganu, D. phaseolorum and D. hongkongensis in Pahang, whereas D. arecae only in Terengganu. The role of the Diaporthe isolates in causing stem gray blight of H. polyrhizus was confirmed. To date, only D. phaseolorum has been previously reported on Hylocereus undatus. This is the first report on D. arecae, D. eugeniae, D. hongkongensis, D. phaseolorum, and D. tectonendophytica causing stem gray blight of H. polyrhizus worldwide.
Fulltext Comparing the efficacy of tocilizumab with corticosteroid therapy in treating COVID-19 patients: a systematic review and meta-analysis

Lim PC, Wong KL, Rajah R, Chong MF, Chow TS, Subramaniam S, et al.

Daru, 2022 Jun;30(1):211-228.
PMID: 35084705 DOI: 10.1007/s40199-021-00430-8

PURPOSE: Tocilizumab has shown equivocal outcomes in reducing mortality in COVID-19. The corticosteroids appear to be an affordable alternative to tocilizumab. This study aims to estimate the efficacy of tocilizumab and the corticosteroids particularly dexamethasone and methylprednisolone and to identify possible determinants of their efficacy.
METHODS: Five electronic databases were searched for studies involving tocilizumab, dexamethasone, and methylprednisolone in treating COVID-19. We included case-control and randomized or partially randomized trials. Meta-regression for patient baseline characteristics, co-medications, and tocilizumab dose regimens was performed to identify contributing factors to drug efficacy.
RESULTS: Thirteen randomized controlled trials (RCTs) and twenty-four case-control studies were included in our meta-analysis involving 18,702 patients. Meta-analysis among the RCTs showed that a summary estimate favoring mortality reduction (OR 0.71, 95%CI 0.55 - 0.92) contributed mainly by tocilizumab and dexamethasone. Among case-control studies, meta-analysis showed mortality reduction (OR 0.52, 95%CI 0.36 - 0.75) contributed by tocilizumab and tocilizumab-methylprednisolone combination. Methylprednisolone alone did not reduce mortality except for one study involving high dose pulse therapy. Meta-analysis also found that all three drugs did not significantly reduce mechanical ventilation (OR 0.72, 95%CI 0.32 - 1.60).
CONCLUSION: Tocilizumab and dexamethasone emerge as viable options in reducing mortality in severe COVID-19 patients. A tocilizumab-corticosteroid combination strategy may improve therapeutic outcome in cases where single therapy fails.
WiFi-Powered Sensor Integrated into a Smart Glove with a Fully Fabric Antenna for the Human-Machine Interface

Lee KT, Lim EH, Tan CH, Low JH, Wong KL, Guan C, et al.

ACS Appl Mater Interfaces, 2024 Nov 13;16(45):62914-62924.
PMID: 39497522 DOI: 10.1021/acsami.4c12371

The integration of flexible sensors into human-machine interfaces (HMIs) is in increasing demand for intuitive and effective manipulation. Traditional glove-based HMIs, constrained by nonconformal rigid structures or the need for bulky batteries, face limitations in continuous operation. Addressing this, we introduce yarn-based bend sensors in our smart glove, which are wirelessly powered and harvest energy from a fully textile 5.8 GHz WiFi-band antenna receiver. These sensors exhibit a gauge factor (GF) of 5.60 for strains ranging from 0 to 10%. They show a consistent performance regardless of the straining frequency when being stretched and released at frequencies between 0.1 and 0.7 Hz. This reliability ensures that the sensor output is solely dependent on the yarn's elongation. Accurately detecting finger-bending movements from 0° to 90° in a virtual environment, the sensors enable enhanced degrees of freedom for human finger interaction. When integrated with advanced machine-learning techniques, the system achieves a classification accuracy of 98.75% for object recognition, demonstrating its potential for precise and accurate HMI. Unlike conventional near-field energy transfer methods that rely on magnetic flux and are limited by power loss over distance, our fully textile design effectively harvests microwave energy, showing no voltage deterioration up to 1 m away. This minimalist microwave-powered smart glove represents a significant advancement, offering a viable and practical solution for developing intuitive and reliable HMIs.
Fulltext Effect of Extra-Framework Cations of LTL Nanozeolites to Inhibit Oil Oxidation

Tan KH, Cham HY, Awala H, Ling TC, Mukti RR, Wong KL, et al.

Nanoscale Res Lett, 2015 Dec;10(1):956.
PMID: 26058517 DOI: 10.1186/s11671-015-0956-6

Lubricant oils take significant part in current health and environmental considerations since they are an integral and indispensable component of modern technology. Antioxidants are probably the most important additives used in oils because oxidative deterioration plays a major role in oil degradation. Zeolite nanoparticles (NPs) have been proven as another option as green antioxidants in oil formulation. The anti-oxidative behavior of zeolite NPs is obvious; however, the phenomenon is still under investigation. Herein, a study of the effect of extra-framework cations stabilized on Linde Type L (LTL) zeolite NPs (ca. 20 nm) on inhibition of oxidation in palm oil-based lubricant oil is reported. Hydrophilic LTL zeolites with a Si/Al ratio of 3.2 containing four different inorganic cations (Li(+), Na(+), K(+), Ca(2+)) were applied. The oxidation of the lubricant oil was followed by visual observation, colorimetry, fourier transform infrared (FTIR) spectroscopy, (1)H NMR spectroscopy, total acid number (TAN), and rheology analyses. The effect of extra-framework cations to slow down the rate of oil oxidation and to control the viscosity of oil is demonstrated. The degradation rate of the lubricant oil samples is decreased considerably as the polarizability of cation is increased with the presence of zeolite NPs. More importantly, the microporous zeolite NPs have a great influence in halting the steps that lead to the polymerization of the oils and thus increasing the lifetime of oils.
Fulltext Semi-analytical modelling and evaluation of uniformly doped silicene nanotransistors for digital logic gates

Chuan MW, Wong KL, Riyadi MA, Hamzah A, Rusli S, Alias NE, et al.

PLoS One, 2021;16(6):e0253289.
PMID: 34125874 DOI: 10.1371/journal.pone.0253289

Silicene has attracted remarkable attention in the semiconductor research community due to its silicon (Si) nature. It is predicted as one of the most promising candidates for the next generation nanoelectronic devices. In this paper, an efficient non-iterative technique is employed to create the SPICE models for p-type and n-type uniformly doped silicene field-effect transistors (FETs). The current-voltage characteristics show that the proposed silicene FET models exhibit high on-to-off current ratio under ballistic transport. In order to obtain practical digital logic timing diagrams, a parasitic load capacitance, which is dependent on the interconnect length, is attached at the output terminal of the logic circuits. Furthermore, the key circuit performance metrics, including the propagation delay, average power, power-delay product and energy-delay product of the proposed silicene-based logic gates are extracted and benchmarked with published results. The effects of the interconnect length to the propagation delay and average power are also investigated. The results of this work further envisage the uniformly doped silicene as a promising candidate for future nanoelectronic applications.
Inhibition of palm oil oxidation by zeolite nanocrystals

Tan KH, Awala H, Mukti RR, Wong KL, Rigaud B, Ling TC, et al.

J Agric Food Chem, 2015 May 13;63(18):4655-63.
PMID: 25897618 DOI: 10.1021/acs.jafc.5b00380

The efficiency of zeolite X nanocrystals (FAU-type framework structure) containing different extra-framework cations (Li(+), Na(+), K(+), and Ca(2+)) in slowing the thermal oxidation of palm oil is reported. The oxidation study of palm oil is conducted in the presence of zeolite nanocrystals (0.5 wt %) at 150 °C. Several characterization techniques such as visual analysis, colorimetry, rheometry, total acid number (TAN), FT-IR spectroscopy, (1)H NMR spectroscopy, and Karl Fischer analyses are applied to follow the oxidative evolution of the oil. It was found that zeolite nanocrystals decelerate the oxidation of palm oil through stabilization of hydroperoxides, which are the primary oxidation product, and concurrently via adsorption of the secondary oxidation products (alcohols, aldehydes, ketones, carboxylic acids, and esters). In addition to the experimental results, periodic density functional theory (DFT) calculations are performed to elucidate further the oxidation process of the palm oil in the presence of zeolite nanocrystals. The DFT calculations show that the metal complexes formed with peroxides are more stable than the complexes with alkenes with the same ions. The peroxides captured in the zeolite X nanocrystals consequently decelerate further oxidation toward formation of acids. Unlike the monovalent alkali metal cations in the zeolite X nanocrystals (K(+), Na(+), and Li(+)), Ca(2+) reduced the acidity of the oil by neutralizing the acidic carboxylate compounds to COO(-)(Ca(2+))1/2 species.