MyMedR

Fulltext Thermal inactivation of lipoxygenase in soya bean using superheated steam to produce low beany flavour soya milk

Chong WK, Mah SY, Easa AM, Tan TC

J Food Sci Technol, 2019 Sep;56(9):4371-4379.

PMID: 31478006 DOI: 10.1007/s13197-019-03905-4

Time and temperature parameters of superheated steam (SHS) treatment were optimised using response surface methodology (RSM) for specific lipoxygenase (LOX) activity in soya beans and crude protein content in soya milk. The optimal SHS treatment was obtained at 9.3 min and 119 °C. The predicted values of specific LOX activity and crude protein content by RSM were 0.0098 μmol/(min mg protein) and 3.2%, respectively. These values were experimentally verified to be 0.0081 ± 0.0002 μmol/(min mg protein) and 3.0 ± 0.1%, respectively. Sensory evaluation showed that the beany flavour of soya milk produced from SHS treated soya beans was significantly weaker (P

The effects of acupressure on depression, anxiety and stress in patients with hemodialysis: a randomized controlled trial

Hmwe NT, Subramanian P, Tan LP, Chong WK

Int J Nurs Stud, 2015 Feb;52(2):509-18.

PMID: 25468282 DOI: 10.1016/j.ijnurstu.2014.11.002

Patients with end stage renal disease on hemodialysis are affected by physiological and psychological stressors, which contribute to poor quality of life and negative clinical outcomes. Depression, anxiety, and stress are highly prevalent in this population. Effective interventional strategies are required to manage these psychological symptoms. Acupressure has been believed to be one of the complementary therapies that could promote psychological wellbeing.

A compendium of all-in-one solar-driven water splitting using ZnIn2S4-based photocatalysts: guiding the path from the past to the limitless future

Chong WK, Ng BJ, Tan LL, Chai SP

Chem Soc Rev, 2024 Sep 02.

PMID: 39222069 DOI: 10.1039/d3cs01040f

Photocatalytic water splitting represents a leading approach to harness the abundant solar energy, producing hydrogen as a clean and sustainable energy carrier. Zinc indium sulfide (ZIS) emerges as one of the most captivating candidates attributed to its unique physicochemical and photophysical properties, attracting much interest and holding significant promise in this domain. To develop a highly efficient ZIS-based photocatalytic system for green energy production, it is paramount to comprehensively understand the strengths and limitations of ZIS, particularly within the framework of solar-driven water splitting. This review elucidates the three sequential steps that govern the overall efficiency of ZIS with a sharp focus on the mechanisms and inherent drawbacks associated with each phase, including commonly overlooked aspects such as the jeopardising photocorrosion issue, the neglected oxidative counter surface reaction kinetics in overall water splitting, the sluggish photocarrier dynamics and the undesired side redox reactions. Multifarious material design strategies are discussed to specifically mitigate the formidable limitations and bottleneck issues. This review concludes with the current state of ZIS-based photocatalytic water splitting systems, followed by personal perspectives aimed at elevating the field to practical consideration for future endeavours towards sustainable hydrogen production through solar-driven water splitting.

Fulltext 50 MHz-10 GHz low-power resistive feedback current-reuse mixer with inductive peaking for cognitive radio receiver

Vitee N, Ramiah H, Chong WK, Tan GH, Kanesan J, Reza AW

ScientificWorldJournal, 2014;2014:683971.

PMID: 25133252 DOI: 10.1155/2014/683971

A low-power wideband mixer is designed and implemented in 0.13 µm standard CMOS technology based on resistive feedback current-reuse (RFCR) configuration for the application of cognitive radio receiver. The proposed RFCR architecture incorporates an inductive peaking technique to compensate for gain roll-off at high frequency while enhancing the bandwidth. A complementary current-reuse technique is used between transconductance and IF stages to boost the conversion gain without additional power consumption by reusing the DC bias current of the LO stage. This downconversion double-balanced mixer exhibits a high and flat conversion gain (CG) of 14.9 ± 1.4 dB and a noise figure (NF) better than 12.8 dB. The maximum input 1-dB compression point (P1dB) and maximum input third-order intercept point (IIP3) are -13.6 dBm and -4.5 dBm, respectively, over the desired frequency ranging from 50 MHz to 10 GHz. The proposed circuit operates down to a supply headroom of 1 V with a low-power consumption of 3.5 mW.

Fulltext Ultra-low-voltage CMOS-based current bleeding mixer with high LO-RF isolation

Tan GH, Sidek RM, Ramiah H, Chong WK, Lioe de X

ScientificWorldJournal, 2014;2014:163414.

PMID: 25197694 DOI: 10.1155/2014/163414

This journal presents an ultra-low-voltage current bleeding mixer with high LO-RF port-to-port isolation, implemented on 0.13 μm standard CMOS technology for ZigBee application. The architecture compliments a modified current bleeding topology, consisting of NMOS-based current bleeding transistor, PMOS-based switching stage, and integrated inductors achieving low-voltage operation and high LO-RF isolation. The mixer exhibits a conversion gain of 7.5 dB at the radio frequency (RF) of 2.4 GHz, an input third-order intercept point (IIP3) of 1 dBm, and a LO-RF isolation measured to 60 dB. The DC power consumption is 572 µW at supply voltage of 0.45 V, while consuming a chip area of 0.97 × 0.88 mm(2).

Fulltext The Chemical Components of Sesbania grandiflora Root and Their Antituberculosis Activity

Hasan N, Osman H, Mohamad S, Chong WK, Awang K, Zahariluddin AS

Pharmaceuticals (Basel), 2012;5(8):882-9.

PMID: 24280680 DOI: 10.3390/ph5080882

Three isoflavanoids, isovestitol (1), medicarpin (2), and sativan (3), along with another known compound, betulinic acid (4), were isolated from the root of Sesbania grandiflora. The structures of the isolated compounds were characterised by means of spectroscopic techniques (UV, IR, MS, 1H- and 13C-NMR, DEPT, COSY, HMQC, HMBC, and MS analysis). All the tested compounds 1-4 exhibited antituberculosis activity against Mycobacterium tuberculosis H37Rv, with MIC values of 50 µg/mL for compounds 1-3, and 100 µg/mL for compound 4, whereas, the methanol extract exhibited antituberculosis activity of 625 µg/mL. This is the first report on the occurrence of isoflavonoids in this plant and their antituberculosis activity.

Fulltext Micturition in the toilet compared with bedpan in laboring Nulliparas: a randomized controlled trial

Kamarudin M, Chong WK, Hamdan M, Adlan AS, Saaid R, Tan PC

BMC Pregnancy Childbirth, 2022 Nov 04;22(1):812.

PMID: 36333791 DOI: 10.1186/s12884-022-05162-4

BACKGROUND: Bladder overdistension in labor may lead to prolonged postpartum urinary retention. We hypothesized that nulliparas mobilizing to toilet is more likely to achieve satisfactory micturition.

METHODS: One hundred sixteen (58 in each arm) term nulliparas in labor with filled bladders were randomized to mobilizing to the toilet or using bedpan to micturate. Primary outcome was satisfactory micturition defined as ultrasound derived post-void bladder volume

Fulltext Infectious Sclerouveitis in an Immunocompetent Patient: A Probable Case of Simultaneous Ocular Tuberculosis and Toxoplasmosis

Chong WK, Khoo Kah Kuen K, Mun-Wei L, Ismail AS, Yaakub A

Cureus, 2022 Nov;14(11):e31726.

PMID: 36569731 DOI: 10.7759/cureus.31726

Simultaneous infections of tuberculosis and toxoplasmosis are uncommon in immunocompetent patients. We report a case of a 30-year-old male who presented with right eye redness and blurring of vision for one month. The visual acuities were hand movement and Snellen 20/30 in the right and left eyes, respectively. Panuveitis and scleritis were found in the right eye, together with dense vitritis and a large choroidal lesion that extended from the inferonasal to the superotemporal quadrants. B-scan ultrasonography of the right eye showed a choroidal detachment with scleral thickening and subtenon fluid. His IgM anti-Toxoplasma antibody was detected, and his QuantiFERON Gold testing was positive. Magnetic resonance imaging (MRI) of the orbit revealed an enhancing intraocular mass at the lateral and inferior aspects of the right globe. The diagnosis of right eye sclerouveitis with presumed tuberculosis and toxoplasmosis co-infections was made. He was treated with a course of oral azithromycin and anti-tubercular therapy along with systemic prednisolone and a topical steroid. The treatment reduced the inflammation; however, the patient suffered from a sequela of chronic uveitis with prolonged hypotony. Medical treatment alone may be insufficient in treating severe infective sclerouveitis, hence surgical intervention might be warranted to provide favorable clinical outcomes.

Fulltext Insights from density functional theory calculations on heteroatom P-doped ZnIn2S4 bilayer nanosheets with atomic-level charge steering for photocatalytic water splitting

Chong WK, Ng BJ, Er CC, Tan LL, Chai SP

Sci Rep, 2022 Feb 04;12(1):1927.

PMID: 35121781 DOI: 10.1038/s41598-022-05740-8

ZnIn2S4 (ZIS) is an efficient photocatalyst for solar hydrogen (H2) generation from water splitting owing to its suitable band gap, excellent photocatalytic behaviour and high stability. Nevertheless, modifications are still necessary to further enhance the photocatalytic performance of ZIS for practical applications. This has led to our interest in exploring phosphorus doping on ZIS for photocatalytic water splitting, which has not been studied till date. Herein, phosphorus-doped ZnIn2S4 (P-ZIS) was modelled via Density Functional Theory to investigate the effects of doping phosphorus on the structural and electronics properties of ZIS as well as its performance toward photocatalytic water splitting. This work revealed that the replacement of S3 atom by substitutional phosphorus gave rise to the most stable P-ZIS structure. In addition, P-ZIS was observed to experience a reduction in band gap energy, an upshift of valence band maximum (VBM), an increase in electron density near VBM and a reduction of H* adsorption-desorption barrier, all of which are essential for the enhancement of the hydrogen evolution reaction. In overall, detailed theoretical analysis carried out in this work could provide critical insights towards the development of P-ZIS-based photocatalysts for efficient H2 generation via solar water splitting.

Fulltext Self-activated superhydrophilic green ZnIn2S4 realizing solar-driven overall water splitting: close-to-unity stability for a full daytime

Chong WK, Ng BJ, Lee YJ, Tan LL, Putri LK, Low J, et al.

Nat Commun, 2023 Nov 24;14(1):7676.

PMID: 37996415 DOI: 10.1038/s41467-023-43331-x

Engineering an efficient semiconductor to sustainably produce green hydrogen via solar-driven water splitting is one of the cutting-edge strategies for carbon-neutral energy ecosystem. Herein, a superhydrophilic green hollow ZnIn2S4 (gZIS) was fabricated to realize unassisted photocatalytic overall water splitting. The hollow hierarchical framework benefits exposure of intrinsically active facets and activates inert basal planes. The superhydrophilic nature of gZIS promotes intense surface water molecule interactions. The presence of vacancies within gZIS facilitates photon energy utilization and charge transfer. Systematic theoretical computations signify the defect-induced charge redistribution of gZIS enhancing water activation and reducing surface kinetic barriers. Ultimately, the gZIS could drive photocatalytic pure water splitting by retaining close-to-unity stability for a full daytime reaction with performance comparable to other complex sulfide-based materials. This work reports a self-activated, single-component cocatalyst-free gZIS with great exploration value, potentially providing a state-of-the-art design and innovative aperture for efficient solar-driven hydrogen production to achieve carbon-neutrality.

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