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Fulltext Risk analysis of musculoskeletal pain intervention using corticosteroid during COVID-19 pandemic: a cohort study

Mohamad AA, Mohamed NA

Korean J Pain, 2023 Jan 01;36(1):106-112.
PMID: 36514932 DOI: 10.3344/kjp.22249

BACKGROUND: Most international bodies recommended against musculoskeletal steroid injection during the COVID-19 pandemic, fearing that the immunosuppressive effects of the steroid could worsen COVID-19 infection, thus prolonging the suffering of patients with severe musculoskeletal disease. The authors' aim is to analyze the risk of COVID-19 infection after musculoskeletal injections.
METHODS: This is a retrospective study of patients who visited a sports medicine clinic and received musculoskeletal steroid injections between January 1, 2020 and February 28, 2021. The collected data was compared with the national COVID-19 registry to identify positive COVID-19 patients. The patients were only considered positive for COVID-19 following corticosteroid injection within 3 months after injection.
RESULTS: Out of 502 steroid injections; 79.7% (n = 400) received a single injection in one day, 19.1% (n = 96) received steroid injections at 2 sites in one day, and 1.2% (n = 6) received steroid injections at 3 sites in one day. Using the Fisher's exact test, there was no statistically significant association of COVID-19 infection between the steroid group and control group (relative risk, 1.44; 95% confidence interval, 0.9-23.1, P = 0.654). Only one patient contracted mild COVID-19 with no post COVID complications.
CONCLUSIONS: The authors recommend the use of musculoskeletal steroid injections in clinically indicated situation without having increased risk of COVID-19.
Fulltext A Rare Presentation of Probable Training-Related Chronic Myopericarditis in an Endurance Cyclist: A Case Report

Mohamad AA, Mohamed NA

Korean J Fam Med, 2024 Mar;45(2):116-120.
PMID: 38351744 DOI: 10.4082/kjfm.23.0082

We report a rare case of high-volume training-related myopericarditis. A male, 18 years old, elite road bicycle racing cyclist with high-volume training of 1,000 km per week for >7 years, presented with progressively worsening exertional breathlessness, reduced effort tolerance, and one episode of cardiac syncope. The symptoms were present prior to the coronavirus disease 2019 pandemic but made worse with the sudden increase in the volume of training after lockdown periods in preparation for competition. He exhibited multiple premature ventricular ectopic beats during his resting electrocardiogram, with a normal echocardiogram and non-elevated cardiac enzyme. The exercise stress test revealed similar multiple premature ventricular beats, warranting further investigation using cardiac magnetic resonance imaging (MRI). The findings of the cardiac MRI were suggestive of myopericarditis. He was instructed to refrain from training and initially started with a short course of colchicine. However, his symptoms deteriorated, and cardiac MRI revealed a decrease in the left ventricular ejection fraction from 59% to 50%. His treatment was escalated to a short course of tapered dose steroid, anti-failure medication and gradual, supervised, return to sports program. This case report highlights the discussion of return to play in athletes with myopericarditis.
Fulltext Poly(2,6-Dimethyl-1,4-Phenylene Oxide)-Based Hydroxide Exchange Separator Membranes for Zinc-Air Battery

Abbasi A, Hosseini S, Somwangthanaroj A, Mohamad AA, Kheawhom S

Int J Mol Sci, 2019 Jul 26;20(15).
PMID: 31357565 DOI: 10.3390/ijms20153678

Rechargeable zinc-air batteries are deemed as the most feasible alternative to replace lithium-ion batteries in various applications. Among battery components, separators play a crucial role in the commercial realization of rechargeable zinc-air batteries, especially from the viewpoint of preventing zincate (Zn(OH)42-) ion crossover from the zinc anode to the air cathode. In this study, a new hydroxide exchange membrane for zinc-air batteries was synthesized using poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) as the base polymer. PPO was quaternized using three tertiary amines, including trimethylamine (TMA), 1-methylpyrolidine (MPY), and 1-methylimidazole (MIM), and casted into separator films. The successful synthesis process was confirmed by proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy, while their thermal stability was examined using thermogravimetric analysis. Besides, their water/electrolyte absorption capacity and dimensional change, induced by the electrolyte uptake, were studied. Ionic conductivity of PPO-TMA, PPO-MPY, and PPO-MIM was determined using electrochemical impedance spectroscopy to be 0.17, 0.16, and 0.003 mS/cm, respectively. Zincate crossover evaluation tests revealed very low zincate diffusion coefficient of 1.13 × 10-8, and 0.28 × 10-8 cm2/min for PPO-TMA, and PPO-MPY, respectively. Moreover, galvanostatic discharge performance of the primary batteries assembled using PPO-TMA and PPO-MPY as initial battery tests showed a high specific discharge capacity and specific power of ~800 mAh/gZn and 1000 mWh/gZn, respectively. Low zincate crossover and high discharge capacity of these separator membranes makes them potential materials to be used in zinc-air batteries.
Fulltext Correction: Abbasi, A. et al. Poly(2,6-dimethyl-1,4-phenylene oxide)-Based Hydroxide Exchange Separator Membranes for Zinc-Air Battery. Int. J. Mol. Sci. 2019, 20, 3678

Abbasi A, Hosseini S, Somwangthanaroj A, Mohamad AA, Kheawhom S

Int J Mol Sci, 2020 01 07;21(2).
PMID: 31936147 DOI: 10.3390/ijms21020377

The authors would like to make the following corrections to their paper published in the International Journal of Molecular Science [...].
Fulltext δ-MnO2 nanoflower/graphite cathode for rechargeable aqueous zinc ion batteries

Khamsanga S, Pornprasertsuk R, Yonezawa T, Mohamad AA, Kheawhom S

Sci Rep, 2019 Jun 11;9(1):8441.
PMID: 31186468 DOI: 10.1038/s41598-019-44915-8

Manganese oxide (MnO2) is one of the most promising intercalation cathode materials for zinc ion batteries (ZIBs). Specifically, a layered type delta manganese dioxide (δ-MnO2) allows reversible insertion/extraction of Zn2+ ions and exhibits high storage capacity of Zn2+ ions. However, a poor conductivity of δ-MnO2, as well as other crystallographic forms, limits its potential applications. This study focuses on δ-MnO2 with nanoflower structure supported on graphite flake, namely MNG, for use as an intercalation host material of rechargeable aqueous ZIBs. Pristine δ-MnO2 nanoflowers and MNG were synthesized and examined using X-ray diffraction, electron spectroscopy, and electrochemical techniques. Also, performances of the batteries with the pristine δ-MnO2 nanoflowers and MNG cathodes were studied in CR2032 coin cells. MNG exhibits a fast insertion/extraction of Zn2+ ions with diffusion scheme and pseudocapacitive behavior. The battery using MNG cathode exhibited a high initial discharge capacity of 235 mAh/g at 200 mA/g specific current density compared to 130 mAh/g which is displayed by the pristine δ-MnO2 cathode at the same specific current density. MNG demonstrated superior electrical conductivity compared to the pristine δ-MnO2. The results obtained pave the way for improving the electrical conductivity of MnO2 by using graphite flake support. The graphite flake support significantly improved performances of ZIBs and made them attractive for use in a wide variety of energy applications.
Combustion in porous media and its applications--a comprehensive survey

Mujeebu MA, Abdullah MZ, Bakar MZ, Mohamad AA, Muhad RM, Abdullah MK

J Environ Manage, 2009 Jun;90(8):2287-312.
PMID: 19299066 DOI: 10.1016/j.jenvman.2008.10.009

The rapid advances in technology and improved living standard of the society necessitate abundant use of fossil fuels which poses two major challenges to any nation. One is fast depletion of fossil fuel resources; the other is environmental pollution. The porous medium combustion (PMC) has proved to be one of the technically and economically feasible options to tackle the aforesaid problems to a remarkable extent. PMC has interesting advantages compared with free flame combustion due to the higher burning rates, the increased power dynamic range, the extension of the lean flammability limits, and the low emissions of pollutants. This article provides a comprehensive picture of the global scenario of research and developments in PMC and its applications that enable a researcher to decide the direction of further investigation. The works published so far in this area are reviewed, classified according to their objectives and presented in an organized manner with general conclusions. A separate section is devoted for the numerical modeling of PMC.
Fulltext Carboxymethyl cellulose-based polyelectrolyte as cationic exchange membrane for zinc-iodine batteries

Tangthuam P, Pimoei J, Mohamad AA, Mahlendorf F, Somwangthanaroj A, Kheawhom S

Heliyon, 2020 Oct;6(10):e05391.
PMID: 33150216 DOI: 10.1016/j.heliyon.2020.e05391

The aim of this research is an evaluation of polyelectrolytes. In the application of zinc-iodine batteries (ZIBs), polyelectrolytes have high stability, good cationic exchange properties and high ionic conductivity. Polyelectrolytes are also cost-effective. Important component of ZIBs are cation exchange membranes (CEMs). CEMs prevent the crossover of iodine and polyiodide from zinc (Zn) electrodes. However, available CEMs are costly and have limited ionic conductivity at room temperature. CEMs are low-cost, have high stability and good cationic exchange properties. Herein, polyelectrolyte membranes prepared from carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA) are examined. It is seen that an increase in the ratio of PVA leads to enhanced ionic conductivity as well as increased iodine and polyiodide crossover. ZIBs using polyelectrolytes having 75:25 wt.% CMC/PVA and 50:50 wt.% CMC/PVA show decent performance and cycling stability. Due to their low-cost and other salient features, CMC/PVA polyelectrolytes prove they have the capacity for use as cation exchange separators in ZIBs.
Author Correction: Compressed composite carbon felt as a negative electrode for a zinc-iron flow battery

Saupsor J, Sangsawang J, Kao-Ian W, Mahlendorf F, Mohamad AA, Cheacharoen R, et al.

Sci Rep, 2023 Apr 04;13(1):5494.
PMID: 37016007 DOI: 10.1038/s41598-023-32392-z
Fulltext Compressed composite carbon felt as a negative electrode for a zinc-iron flow battery

Saupsor J, Sangsawang J, Kao-Ian W, Mahlendorf F, Mohamad AA, Cheacharoen R, et al.

Sci Rep, 2022 Dec 07;12(1):21156.
PMID: 36477629 DOI: 10.1038/s41598-022-25763-5

Flow batteries possess several attractive features including long cycle life, flexible design, ease of scaling up, and high safety. They are considered an excellent choice for large-scale energy storage. Carbon felt (CF) electrodes are commonly used as porous electrodes in flow batteries. In vanadium flow batteries, both active materials and discharge products are in a liquid phase, thus leaving no trace on the electrode surface. However, zinc-based flow batteries involve zinc deposition/dissolution, structure and configuration of the electrode significantly determine stability and performance of the battery. Herein, fabrication of a compressed composite using CF with polyvinylidene fluoride (PVDF) is investigated in a Zn-Fe flow battery (ZFB). Graphene (G) is successfully introduced in order to improve its electrochemical activity towards zinc reactions on the negative side of the ZFB. A compressed composite CF electrode offers more uniform electric field and lower nucleation overpotential (NOP) of zinc than a pristine CF, resulting in higher zinc plating/stripping efficiency. Batteries with modified electrodes are seen to provide lower overpotential. Particularly, the G-PVDF-CF electrode demonstrates maximum discharge capacity of 39.6 mAh cm-2 with coulombic efficiency and energy efficiency over 96% and 61%, respectively. Finally, results lead to increased efficiency and cycling stability for flow batteries.
COVID-19 pandemic: Public attitudes and opinions on a global health crisis among residents in Sarawak, Malaysia

Wan Ibrahim WH, Thong JZ, Lo MC, Mohamad AA, Ching JL

J Emerg Manag, 2023;21(5):469-479.
PMID: 37932948 DOI: 10.5055/jem.0777

In Sarawak, Malaysia, several exceptional safety precautions and measures were adopted to prevent the outbreak of coronavirus disease 2019 (COVID-19) pandemic from spreading. Individuals' attitudes and opinions have impact on their obedience toward control procedures. Sarawak residents' attitudes and opinions toward COVID-19 were investigated in the present study. An online questionnaire developed using Google Forms was completed by 1,462 residents from all 12 divisions in Sarawak. The findings show that most Sarawak residents have positive attitudes and opinions about current standard operating procedures (SOPs) toward COVID-19. More than half of the respondents stand unbiased for the effectiveness of these SOPs, while most respondents have a neutral standpoint regarding the current law enforcement. The partial least square regression results found using the WarpPLS 7.0 software indicate that Sarawak residents' attitudes, opinions about current SOPs, and their effectiveness are significantly linked to practices for the prevention of COVID-19 outbreak, whereas these residents' opinions about current law enforcement were observed to have no significant relationship with proper practices for measures.
Radiation and temperature effects on conductivity properties of PVA-KOH-PC composite

Mohd Asri MT, Elias S, Iskandar SM, Abd Halim S, Jumiah H, Zaki AR, et al.

Med J Malaysia, 2004 May;59 Suppl B:139-40.
PMID: 15468857

The aim of this work was to study radiation and the effects of temperature on conductivity properties of polyvinyl alcohol (PVA)-based potassium hydroxide (KOH) and propylene carbonate (PC), where the ionic conduction preferentially occurs in the amorphous phase by free radicals ions through gamma-irradiation. Alkaline composite polymer electrolyte (ACPE) consisting of PVA, KOH and PC of different concentration ratios were prepared by solvent-casting technique. The ACPE were irradiated with different doses from 5 kGy up to 200 kGy. The conductivity properties of the electrolyte films were measured at different frequencies in the range 20 Hz to 1 MHz using LCR meter. The results showed that the conductivity properties were dependent on the radiation dose, temperature and the concentration of the polymer blends.
Stabilizing a zinc anode via a tunable covalent organic framework-based solid electrolyte interphase

Aupama V, Kao-Ian W, Sangsawang J, Mohan G, Wannapaiboon S, Mohamad AA, et al.

Nanoscale, 2023 May 25;15(20):9003-9013.
PMID: 37128979 DOI: 10.1039/d3nr00898c

Zinc (Zn) is an excellent material for use as an anode for rechargeable batteries in water-based electrolytes. Nevertheless, the high activity of water leads to Zn corrosion and hydrogen evolution, along with the formation of dendrites on the Zn surface during repeated charge-discharge (CD) cycles. To protect the Zn anode and limit parasitic side reactions, an artificial solid electrolyte interphase (ASEI) protective layer is an effective strategy. Herein, an ASEI made of a covalent organic framework (COFs: HqTp and BpTp) was fabricated on the surface of a Zn anode via Schiff base reactions of aldehyde and amine linkers. It is seen that COFs can regulate the Zn-ion flux, resulting in dendritic-free Zn. COFs can also mitigate the formation of an irreversible passive layer and the hydrogen evolution reaction (HER). Zn plating/stripping tests using a symmetrical cell suggest that HqTpCOF@Zn shows superior stability and greater coulombic efficiency (CE) compared to bare Zn. The full cell having COFs@Zn also displays much improved cyclability. As a result, the COF proves to be a promising ASEI material to enhance the stability of the Zn anode in aqueous media.