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Garlic supplementation and serum cholesterol: a meta-analysis

Khoo YS, Aziz Z

J Clin Pharm Ther, 2009 Apr;34(2):133-45.
PMID: 19250134 DOI: 10.1111/j.1365-2710.2008.00998.x

Prevention of cardiovascular disease by modifying its major risk factors, including serum cholesterol levels, is an important strategy. Regular intake of garlic has been suggested, but its impact on cholesterol levels has been inconsistent.
Fulltext Eco-friendly surface modification approach to develop thin film nanocomposite membrane with improved desalination and antifouling properties

Khoo YS, Lau WJ, Liang YY, Karaman M, Gürsoy M, Ismail AF

J Adv Res, 2022 Feb;36:39-49.
PMID: 35127163 DOI: 10.1016/j.jare.2021.06.011

INTRODUCTION: Nanomaterials aggregation within polyamide (PA) layer of thin film nanocomposite (TFN) membrane is found to be a common issue and can negatively affect membrane filtration performance. Thus, post-treatment on the surface of TFN membrane is one of the strategies to address the problem.
OBJECTIVE: In this study, an eco-friendly surface modification technique based on plasma enhanced chemical vapour deposition (PECVD) was used to deposit hydrophilic acrylic acid (AA) onto the PA surface of TFN membrane with the aims of simultaneously minimizing the PA surface defects caused by nanomaterials incorporation and improving the membrane surface hydrophilicity for reverse osmosis (RO) application.
METHODS: The TFN membrane was first synthesized by incorporating 0.05 wt% of functionalized titania nanotubes (TNTs) into its PA layer. It was then subjected to 15-s plasma deposition of AA monomer to establish extremely thin hydrophilic layer atop PA nanocomposite layer. PECVD is a promising surface modification method as it offers rapid and solvent-free functionalization for the membranes.
RESULTS: The findings clearly showed that the sodium chloride rejection of the plasma-modified TFN membrane was improved with salt passage reduced from 2.43% to 1.50% without significantly altering pure water flux. The AA-modified TFN membrane also exhibited a remarkable antifouling property with higher flux recovery rate (>95%, 5-h filtration using 1000 mg/L sodium alginate solution) compared to the unmodified TFN membrane (85.8%), which is mainly attributed to its enhanced hydrophilicity and smoother surface. Furthermore, the AA-modified TFN membrane also showed higher performance stability throughout 12-h filtration period.
CONCLUSION: The deposition of hydrophilic material on the TFN membrane surface via eco-friendly method is potential to develop a defect-free TFN membrane with enhanced fouling resistance for improved desalination process.
Rapid Surface Modification of Ultrafiltration Membranes for Enhanced Antifouling Properties

Said N, Khoo YS, Lau WJ, Gürsoy M, Karaman M, Ting TM, et al.

Membranes (Basel), 2020 Dec 07;10(12).
PMID: 33297433 DOI: 10.3390/membranes10120401

In this work, several ultrafiltration (UF) membranes with enhanced antifouling properties were fabricated using a rapid and green surface modification method that was based on the plasma-enhanced chemical vapor deposition (PECVD). Two types of hydrophilic monomers-acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) were, respectively, deposited on the surface of a commercial UF membrane and the effects of plasma deposition time (i.e., 15 s, 30 s, 60 s, and 90 s) on the surface properties of the membrane were investigated. The modified membranes were then subjected to filtration using 2000 mg/L pepsin and bovine serum albumin (BSA) solutions as feed. Microscopic and spectroscopic analyses confirmed the successful deposition of AA and HEMA on the membrane surface and the decrease in water contact angle with increasing plasma deposition time strongly indicated the increase in surface hydrophilicity due to the considerable enrichment of the hydrophilic segment of AA and HEMA on the membrane surface. However, a prolonged plasma deposition time (>15 s) should be avoided as it led to the formation of a thicker coating layer that significantly reduced the membrane pure water flux with no significant change in the solute rejection rate. Upon 15-s plasma deposition, the AA-modified membrane recorded the pepsin and BSA rejections of 83.9% and 97.5%, respectively, while the HEMA-modified membrane rejected at least 98.5% for both pepsin and BSA. Compared to the control membrane, the AA-modified and HEMA-modified membranes also showed a lower degree of flux decline and better flux recovery rate (>90%), suggesting that the membrane antifouling properties were improved and most of the fouling was reversible and could be removed via simple water cleaning process. We demonstrated in this work that the PECVD technique is a promising surface modification method that could be employed to rapidly improve membrane surface hydrophilicity (15 s) for the enhanced protein purification process without using any organic solvent during the plasma modification process.
Fulltext Development of Ultrahigh Permeance Hollow Fiber Membranes via Simple Surface Coating for CO2/CH4 Separation

Said N, Wong KC, Lau WJ, Khoo YS, Yeong YF, Othman NH, et al.

Molecules, 2022 Dec 01;27(23).
PMID: 36500475 DOI: 10.3390/molecules27238381

Most researchers focused on developing highly selective membranes for CO2/CH4 separation, but their developed membranes often suffered from low permeance. In this present work, we aimed to develop an ultrahigh permeance membrane using a simple coating technique to overcome the trade-off between membrane permeance and selectivity. A commercial silicone membrane with superior permeance but low CO2/CH4 selectivity (in the range of 2-3) was selected as the host for surface modification. Our results revealed that out of the three silane agents tested, only tetraethyl orthosilicate (TEOS) improved the control membrane's permeance and selectivity. This can be due to its short structural chain and better compatibility with the silicone substrate. Further investigation revealed that higher CO2 permeance and selectivity could be attained by coating the membrane with two layers of TEOS. The surface integrity of the TEOS-coated membrane was further improved when an additional polyether block amide (Pebax) layer was established atop the TEOS layer. This additional layer sealed the pin holes of the TEOS layer and enhanced the resultant membrane's performance, achieving CO2/CH4 selectivity of ~19 at CO2 permeance of ~2.3 × 105 barrer. This performance placed our developed membrane to surpass the 2008 Robeson Upper Boundary.