Displaying publications 41 - 60 of 81 in total

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  1. Wong CY, Khairi MD, Mohamed SA, Irfan M
    Med J Malaysia, 2010 Dec;65(4):307-8.
    PMID: 21901952
    Dural exposure may occur during the course of thinning the tegmen tympani and tegmen mastoideum in mastoid procedure. If large area of dura is exposed or lacerated, cerebrospinal fluid and brain herniation may enter the mastoid cavity. We report a case of a patient with injured dura mater and tegmen mastoideum during mastoidectomy for chronic suppurative otitis media with cholesteatoma managed by using DuraGen. The dura mater and tegmen defect healed totally showing the success of the procedure. A collagen matrix like DuraGen is an option for repairing dural tear in mastoid region.
  2. Irfan M, Susibalan BD, Nik Fariza Husna NH
    Malays Fam Physician, 2013;8(3):49-50.
    PMID: 25893061 MyJurnal
  3. Razzaq A, Sharif A, Aziz N, Irfan M, Jermsittiparsert K
    Environ Res, 2020 Dec;191:110189.
    PMID: 32919963 DOI: 10.1016/j.envres.2020.110189
    This study draws the link between COVID-19 and air pollution (ground ozone O3) from February 29, 2020 to July 10, 2020 in the top 10 affected States of the US. Utilizing quantile-on-quantile (QQ) estimation technique, we examine in what manner the quantiles of COVID-19 affect the quantiles of air pollution and vice versa. The primary findings confirm overall dependence between COVID-19 and air pollution. Empirical results exhibit a strong negative effect of COVID-19 on air pollution in New York, Texas, Illinois, Massachusetts, and Pennsylvania; especially at medium to higher quantiles, while New Jersey, Illinois, Arizona, and Georgia show strong negative effect mainly at lower quantiles. Contrarily, COVID-19 positively affects air pollution in Pennsylvania at extreme lower quantiles. On the other side, air pollution predominantly caused to increase in the intensity of COVID-19 cases across all states except lower quantiles of Massachusetts, and extreme higher quantiles of Arizona and New Jersey, where this effect becomes less pronounced or negative. Concludingly, a rare positive fallout of COVID-19 is reducing environmental pressure, while higher environmental pollution causes to increase the vulnerability of COVID-19 cases. These findings imply that air pollution is at the heart of chronic diseases, therefore the state government should consider these asymmetric channels and introduce appropriate policy measures to reset and control atmospheric emissions.
  4. Irfan M, Ismail SB, Noor NM, Hussain NHN
    Am J Mens Health, 2020 10 29;14(5):1557988320969082.
    PMID: 33111628 DOI: 10.1177/1557988320969082
    One of the major causes of erectile dysfunction (ED) is an endothelial vascular disorder. This meta-analysis is performed to determine the efficacy of aspirin on erectile function in men with vasculogenic ED. For this purpose, CENTRAL, MEDLINE, and reference lists of articles up to November 2019 were searched. Randomized controlled trials (RCTs) were selected that compared aspirin with placebo in men of any ethnicity with vasculogenic ED. A total of 58 trials were retrieved. Finally, two trials of 214 men fulfilled our selection criteria. High selection and detection bias were identified for one trial. The participants showed a significant improvement in erectile function when they took aspirin (mean difference: 5.14, 95% CI [3.89, 6.40], and I2 = 0%). Although the present meta-analysis suggested that aspirin has a significant effect on the improvement of erectile function, there were limited RCTs available on this topic and doses of aspirin varied. Additional studies are needed to support findings from this meta-analysis. Aspirin needs to be considered by practitioners when prescribing drugs for vasculogenic ED.
  5. Zhao JX, Wang LY, Irfan M, Zhang ZS
    Zootaxa, 2021 Aug 13;5020(3):457-488.
    PMID: 34810991 DOI: 10.11646/zootaxa.5020.3.3
    The cribellate, Asian endemic, spider genus, Taira is further studied, and six new species are recognized and described from China and Eastern Malaysia (Borneo): Taira borneoensis sp. nov. (♀), Taira gyaisiensis sp. nov. (♀), Taira nyagqukaensis sp. nov. (♀), Taira wanzhouensis sp. nov. (♂♀), Taira xuanenensis sp. nov. (♂) and Taira yangi sp. nov. (♂♀). Males of Taira latilabiata Zhang, Zhu Song, 2008 and Taira obtusa Zhang, Zhu Song, 2008 are also described for the first time. Drawings of the copulatory organs of the six new species, and comparative photos of the habitus and copulatory organs of all described species are provided, except for the male palp of the type species, T. flavidorsalis (Yaginuma, 1964). New records of known species and distribution maps are presented.
  6. Tan B, Irfan M, Zhang ZS, Wang LY
    Zookeys, 2023;1182:1-9.
    PMID: 37868119 DOI: 10.3897/zookeys.1182.109532
    The genus Passiena is recorded for the first time from China with Passienaduanisp. nov. (♂♀) from Guangxi described here. In addition, the male of P.spinicrus Thorell, 1890 is described for the first time based on a specimen from Malaysia and colour photographs of freshly collected material are also presented. Detailed morphological descriptions, photographs, genital illustrations, and a distribution map for the two species are provided.
  7. Irfan M, Yahia D, Nik Fariza Husna NH, Wan Shah Jihan WD, Baharudin A
    Med J Malaysia, 2012 Feb;67(1):113-5.
    PMID: 22582561 MyJurnal
    A case of a 21 year old gentleman is described, with no history of preceding trauma, presenting with intermittent dysphagia to solids and fluids for 4 years. Neck examination at rest was normal. However on deep inspiration, the right thyroid lamina protrudes or becomes more prominent. The patient is able to return the larynx to its normal position with manual manipulation. Laryngeal examination with fibreoptic scope during rest and deep breath shows gross rotation of the laryngeal structures for more than 60 degrees on deep breath, with the vocal cords axis rotated to the left side. Management was conservative.
  8. Ngadiman NH, Idris A, Irfan M, Kurniawan D, Yusof NM, Nasiri R
    J Mech Behav Biomed Mater, 2015 Sep;49:90-104.
    PMID: 26002419 DOI: 10.1016/j.jmbbm.2015.04.029
    Maghemite (γ-Fe2O3) nanoparticle with its unique magnetic properties is recently known to enhance the cell growth rate. In this study, γ-Fe2O3 is mixed into polyvinyl alcohol (PVA) matrix and then electrospun to form nanofibers. Design of experiments was used to determine the optimum parameter settings for the electrospinning process so as to produce elctrospun mats with the preferred characteristics such as good morphology, Young's modulus and porosity. The input factors of the electrospinnning process were nanoparticles content (1-5%), voltage (25-35 kV), and flow rate (1-3 ml/h) while the responses considered were Young's modulus and porosity. Empirical models for both responses as a function of the input factors were developed and the optimum input factors setting were determined, and found to be at 5% nanoparticle content, 35 kV voltage, and 1 ml/h volume flow rate. The characteristics and performance of the optimum PVA/γ-Fe2O3 nanofiber mats were compared with those of neat PVA nanofiber mats in terms of morphology, thermal properties, and hydrophilicity. The PVA/γ-Fe2O3 nanofiber mats exhibited higher fiber diameter and surface roughness yet similar thermal properties and hydrophilicity compared to neat PVA PVA/γ-Fe2O3 nanofiber mats. Biocompatibility test by exposing the nanofiber mats with human blood cells was performed. In terms of clotting time, the PVA/γ-Fe2O3 nanofibers exhibited similar behavior with neat PVA. The PVA/γ-Fe2O3 nanofibers also showed higher cells proliferation rate when MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was done using human skin fibroblast cells. Thus, the PVA/γ-Fe2O3 electrospun nanofibers can be a promising biomaterial for tissue engineering scaffolds.
  9. Ahmad T, Bustam MA, Irfan M, Moniruzzaman M, Asghar HMA, Bhattacharjee S
    Biotechnol Appl Biochem, 2019 Jul;66(4):698-708.
    PMID: 31172593 DOI: 10.1002/bab.1787
    Phytosynthesis of gold nanoparticles (AuNPs) has achieved an indispensable significance due to the diverse roles played by biomolecules in directing the physiochemical characteristics of biosynthesized nanoparticles. Therefore, the precise identification of key bioactive compounds involved in producing AuNPs is vital to control their tunable characteristics for potential applications. Herein, qualitative and quantitative determination of key biocompounds contributing to the formation of AuNPs using aqueous Elaeis guineensis leaves extract is reported. Moreover, roles of phenolic compounds and flavonoids in reduction of Au3+ and stabilization of AuNPs have been elucidated by establishing a reaction mechanism. Fourier-transform infrared spectroscopy (FTIR) showed shifting of O─H stretching vibrations toward longer wavenumbers and C═O toward shorter wavenumbers due to involvement of polyphenolic compounds in biosynthesis and oxidation of polyphenolic into carboxylic compounds, respectively, which cape nanoparticles to inhibit the aggregation. Congruently, pyrolysis-gas chromatography-mass spectrometry revealed the major contribution of polyphenolic compounds in the synthesis of AuNPs, which was further endorsed by reduction of total phenolic and total flavonoids contents from 48.08 ± 1.98 to 9.59 ± 0.92 mg GAE/g and 32.02 ± 1.31 to 13.8 ± 0.97 mg CE/g within 60 Min, respectively. Based on experimental results, reaction mechanism explained the roles of phenolic compounds and flavonoids in producing spherical-shaped AuNPs.
  10. Norhayati MN, Shaiful Bahari I, Zaharah S, Nik Hazlina NH, Mohammad Aimanazrul Z, Irfan M
    BMJ Open, 2020 10 31;10(10):e038364.
    PMID: 33130564 DOI: 10.1136/bmjopen-2020-038364
    PURPOSE: Postoperative atrial fibrillation (POAF) is a potentially lethal and morbid complication after open heart surgery. This systematic review and meta-analysis aimed to investigate metoprolol compared with other treatments for prophylaxis against POAF.

    METHODS: We searched CENTRAL, MEDLINE, EMBASE and trial registries for randomised controlled trials that evaluated metoprolol for preventing the occurrence of POAF after surgery against other treatments or placebo. Random-effects model was used for estimating the risk ratios (RRs) and mean differences with 95% CIs.

    RESULTS: Nine trials involving 1570 patients showed metoprolol reduced POAF compared with placebo (416 patients; RR 0.46, 95% CI 0.33 to 0.66; I²=21%; risk difference (RD) -0.19, 95% CI -0.28 to -0.10). However, metoprolol increased the risk of POAF compared with carvedilol (159 patients; RR 1.59, 95% CI 1.20 to 2.12; I²=4%; RD 0.13, 95% CI 0.06 to 0.20). There was no difference when compared with sotalol or amiodarone. The occurrence of cardiovascular conditions after drugs administration or death between the groups was not different. The overall quality of evidence was moderate to high. Subgroup analysis and funnel plot were not performed.

    CONCLUSIONS: Metoprolol is effective in preventing POAF compared with placebo and showed no difference with class III antiarrhythmic drugs. Death and thromboembolism are associated with open heart surgery, but not significant in relation to the use of metoprolol.

    PROSPERO REGISTRATION NUMBER: CRD42019131585.

  11. Irfan M, Ahmad M, Fareed Z, Iqbal N, Sharif A, Wu H
    PMID: 33448868 DOI: 10.1080/09603123.2021.1874888
    The aim of this study is to identify and highlight the positive and negative indirect environmental impacts of COVID-19, with a particular focus on the most affected economies (USA, China, Spain, and Italy). In this respect, the empirical and theoretical dimensions of the contents of those impacts are analyzed. Research findings reveal a significant relationship between contingency actions and positive indirect impacts such as air quality improvements, clean beaches, and the decline in environmental noise. Besides, negative indirect impacts also exist, such as the rise in waste level and curtailment in recycling, further threatening the physical spaces (land and water), besides air. It is expected that global businesses will revive in the near future (though slowly), but the reduction in greenhouse gas emissions during this short time span is not a sustainable way of environmental mitigation. Thus, long-term mitigation policies should be strengthened to cope with the undesirable deterioration of the environment. Research findings provide an up-to-date glimpse of the pandemic from the perspectives of current and future indirect environmental impacts and the post-pandemic situation. Finally, it is suggested to invent and prepare action plans to induce a sustainable economic and environmental future in the post-pandemic world scenario.
  12. Ismail SB, Noor NM, Hussain NHN, Sulaiman Z, Shamsudin MA, Irfan M
    Am J Mens Health, 2019 12 5;13(6):1557988319892735.
    PMID: 31795911 DOI: 10.1177/1557988319892735
    Erectile dysfunction is common in adult men, particularly those with hypertension and diabetes. The present study determines the effectiveness of angiotensin receptor blocker (ARB) drugs on erectile function in hypertensive male adults. For this purpose, CENTRAL and MEDLINE and reference lists of the articles were searched. The randomized controlled trials (RCTs) were selected that compared ARBs with conventional therapy or no treatment in men of any ethnicity who were presented with hypertension and/or diabetes. A total four trials that had 2,809 men were included. Three trials reported adequate random sequence allocation, two reported adequate blinding. Attrition bias is low in one of the included studies. All three studies are of low risk of selective reporting bias. There was an improvement in sexual activity with ARBs (valsartan) (mean difference (MD): 0.71, 95% Confidence Interval (CI) 0.66 to 0.76, I2 statistic = 0%). However, the erectile functions did not increase significantly in ARBs (losartan or telmisartan) treated men as compared to control or placebo (n = 203 vs n = 232; MD: 1.36; 95% CI: -0.97 to -3.69; I2 statistic = 80%). These results suggested that ARBs significantly improved sexual activity among hypertensive men. However, the erectile function was not significantly improved in ARBs treated men as compared to the control or placebo-treated. There were limited studies available. Hence, additional studies are needed to support findings from this review. ARBs should be considered when prescribing antihypertensive drugs to men.
  13. Irfan M, Hussain NHN, Noor NM, Mohamed M, Ismail SB
    J Sex Med, 2020 03;17(3):412-430.
    PMID: 31955912 DOI: 10.1016/j.jsxm.2019.12.003
    INTRODUCTION: Sexual activity is an essential human need and an important predictor of other aspects of human life. A literature review was conducted to investigate whether sexual abstinence in young and middle-aged men is generally considered a deliberate, healthy behavior and whether it has other causes and consequences.

    AIM: To review the prevalence and factors associated with sexual abstinence in young (10-24 years) and middle-aged (25-59 years) men.

    METHODS: Studies were retrieved from Science Direct, PubMed, and EBSCOhost published from 2008 to 2019. The selection criteria were original population- or community-based articles, published in the English language, on sexual abstinence, and in young and middle-aged men.

    MAIN OUTCOME MEASURE: This article reviewed the literature on the proportions of and factors associated with sexual abstinence in young and middle-aged men.

    RESULTS: A total of 13,154 studies were retrieved, from which data were extracted for 37 population- or community-based studies. The prevalence of sexual abstinence varied from 0% to 83.6% in men younger than 60 years. The prevalence of primary sexual abstinence was 3.4%-83.3% for young men and 12.5%-15.5% for middle-aged men. The prevalence of secondary abstinence for young men ranged from 1.3% to 83.6%, while for middle-aged men, it was from 1.2% to 67.7%. The prevalence of sexual abstinence decreased with increasing age in young men but increased with increasing age in middle-aged men. The significant factors reported were age, single status, poor relationships, low socioeconomic status, sex education, religious practices, caring and monitoring parents, and not using alcohol, cigarettes, or drugs. Although the variations in findings from different studies can be explained by different regions and cultures, the information cannot be generalized worldwide because of a lack of studies in Asian and Australian populations.

    CLINICAL IMPLICATIONS: The studies on sexual abstinence in the future should use a consistent and standard definition, cover all sexual behaviors, and investigate all related factors.

    STRENGTH & LIMITATIONS: The restricted timeframe (2008-2019), English language, availability of full text, and variability in definition and time duration may be the sources of bias.

    CONCLUSION: Young men had higher proportions of sexual abstinence than middle-aged men, and age, unavailability of a partner, lower educational levels, low socioeconomic status, conservative and religious conditions, and no or less knowledge about sexually transmitted infections were common predictors of sexual abstinence in most of the men. Although determinants of sexual abstinence were identified, further investigation of biological factors in men younger than 60 years is needed. Irfan M, Hussain NHN, Noor NM, et al. Sexual Abstinence and Associated Factors Among Young and Middle-Aged Men: A Systematic Review. J Sex Med 2020;17:412-430.

  14. Nasiri R, Dabagh S, Meamar R, Idris A, Muhammad I, Irfan M, et al.
    Nanotechnology, 2020 May 08;31(19):195603.
    PMID: 31978907 DOI: 10.1088/1361-6528/ab6fd4
    The present study aims at engineering, fabrication, characterization, and qualifications of papain (PPN) conjugated SiO2-coated iron oxide nanoparticles 'IONPs@SiO2-PPN'. Initially fabricated iron oxide nanoparticles (IONPs) were coated with silica (SiO2) using sol-gel method to hinder the aggregation and to enhance biocompatibility. Next, PPN was loaded as an anticancer agent into the silica coated IONPs (IONPs@SiO2) for the delivery of papain to the HeLa cancer cells. This fabricated silica-coated based magnetic nanoparticle is introduced as a new physiologically-compatible and stable drug delivery vehicle for delivering of PPN to the HeLa cancer cell line. The IONPs@SiO2-PPN were characterized using FT-IR, AAS, FESEM, XRD, DLS, and VSM equipment. Silica was amended on the surface of iron oxide nanoparticles (IONPs, γ-Fe2O3) to modify its biocompatibility and stability. The solvent evaporation method was used to activate PPN vectorization. The following tests were performed to highlight the compatibility of our proposed delivery vehicle: in vitro toxicity assay, in vivo acute systemic toxicity test, and the histology examination. The results demonstrated that IONPs@SiO2-PPN successfully reduced the IC50 values compared with the native PPN. Also, the structural alternations of HeLa cells exposed to IONPs@SiO2-PPN exhibited higher typical hallmarks of apoptosis compared to the cells treated with the native PPN. The in vivo acute toxicity test indicated no clinical signs of distress/discomfort or weight loss in Balb/C mice a week after the intravenous injection of IONPs@SiO2 (10 mg kg-1). Besides, the tissues architectures were not affected and the pathological inflammatory alternations detection failed. In conclusion, IONPs@SiO2-PPN can be chosen as a potent candidate for further medical applications in the future, for instance as a drug delivery vehicle or hyperthermia agent.
  15. Irfan M, Hussain NHN, Noor NM, Mohamed M, Sidi H, Ismail SB
    Am J Mens Health, 2020 7 7;14(4):1557988320937200.
    PMID: 32623948 DOI: 10.1177/1557988320937200
    Male sexual dysfunctions (MSDs) often remain undiagnosed and untreated in Asia compared to Europe due to conservative cultural and religious beliefs, socioeconomic conditions, and lack of awareness. There is a tendency for the use of traditional medicines and noncompliance with and reduced access to modern healthcare. The present systematic review compared the incidence and factors of MSD in European and Asian populations. English language population/community-based original articles on MSDs published in MEDLINE from 2008 to 2018 were retrieved. A total of 5392 studies were retrieved, of which 50 (25 Asian and 25 European) were finally included in this review. The prevalence of erectile dysfunction (ED) (0%-95.0% vs. 0.9%-88.8%), low satisfaction (3.2%-37.6% vs. 4.1%-28.3%), and hypoactive sexual desire disorder (HSDD) (0.7%-81.4 vs. 0%-65.5%) was higher in Asian than in European men, whereas the prevalence of anorgasmia (0.4% vs. 3%-65%) was lower in Asian than in European men. Age was an independent positive factor of MSD. In European men over 60 years old, the prevalence of premature ejaculation (PE) decreased. The prevalence of MSD was higher in questionnaires than in interviews. The significant factors were age, single status, low socioeconomic status, poor general health, less physical activity, cardiovascular diseases, diabetes, obesity, lower urinary tract symptoms, prostatitis, anxiety, depression and alcohol, tobacco, and drug use. The prevalence of MSD differed slightly in Asian and European men. There is a need to conduct large studies on the various Asian populations for the effective management of MSD.
  16. Irfan M, Shahudin F, Hooper VJ, Akram W, Abdul Ghani RB
    Inquiry, 2021 11 23;58:469580211056217.
    PMID: 34802264 DOI: 10.1177/00469580211056217
    The objective of this article is to examine the impact of coronavirus disease 2019 (COVID-19) upon university students' anxiety level and to find the factors associated with the anxiety level in Malaysia. We collected data from 958 students from 16 different universities using an originally designed questionnaire. The Generalized Anxiety Disorder Scale 7-item (GAD-7) was used to estimate the anxiety. Then we applied the ordered logit model to calculate the odds ratios (OR) and factors associated with the anxiety level. We find that 12.3% of students were normal, whereas 30.5% were experiencing mild anxiety, 31.1% moderate anxiety, and 26.1% severe anxiety. Surprisingly, only 37.2% of students were aware of mental health support that was provided by their universities. However, age above 20 years (OR = 1.30), ethnicity Chinese (OR = 1.72), having any other disease (OR = 2.0), decreased family income (OR = 1.71), more time spent on watching COVID-19-related news (OR = 1.52), and infected relative or friends (OR = 1.62) were risk factors for anxiety among students. We conclude that the government of Malaysia should monitor the mental health of the universities' students more closely and universities should open online mental health support clinics to avoid the adverse impacts of anxiety.
  17. Kumar V, Naik B, Sharma S, Kumar A, Khan JM, Irfan M
    Trop Life Sci Res, 2022 Sep;33(3):151-164.
    PMID: 36545057 DOI: 10.21315/tlsr2022.33.3.9
    Fermented bamboo shoots are rich in high protein, carbohydrates, fibre and minerals while low in fat content. In the North-East region of India and other Asian countries, they are mostly used in various food preparations. The present study was undertaken to explore the diversity of bacteria associated with Bamboo shoots and to evaluate their antibacterial profile. Based on the results the fermented bamboo shoots showed viable counts ranging from 6.55 ± 0.91 log CFU/g to 7.86 ± 1.21 log CFU/g. The 16s rRNA sequence analysis showed that these isolates belonged to the genus Bacillus (Bacillus safensis, B. tequilensis, B. siamensis, B. nakamurai, B. subtilis) and Enterobacter. These isolates have not been reported previously from fermented bamboo shoots except B. subtilis. Surprisingly, no Lactobacillus species or molds were found in any of the samples tested. Potent antibacterial activity was recorded against Klebsiella, Staphylococcus aureus, Salmonella and B. cereus.
  18. Irfan M, Razzaq A, Suksatan W, Sharif A, Madurai Elavarasan R, Yang C, et al.
    J Therm Biol, 2022 Feb;104:103101.
    PMID: 35180949 DOI: 10.1016/j.jtherbio.2021.103101
    The emergence of new coronavirus (SARS-CoV-2) has become a significant public health issue worldwide. Some researchers have identified a positive link between temperature and COVID-19 cases. However, no detailed research has highlighted the impact of temperature on COVID-19 spread in India. This study aims to fill this research gap by investigating the impact of temperature on COVID-19 spread in the five most affected Indian states. Quantile-on-Quantile regression (QQR) approach is employed to examine in what manner the quantiles of temperature influence the quantiles of COVID-19 cases. Empirical results confirm an asymmetric and heterogenous impact of temperature on COVID-19 spread across lower and higher quantiles of both variables. The results indicate a significant positive impact of temperature on COVID-19 spread in the three Indian states (Maharashtra, Andhra Pradesh, and Karnataka), predominantly in both low and high quantiles. Whereas, the other two states (Tamil Nadu and Uttar Pradesh) exhibit a mixed trend, as the lower quantiles in both states have a negative effect. However, this negative effect becomes weak at middle and higher quantiles. These research findings offer valuable policy recommendations.
  19. Ahmad F, Draz MU, Chandio AA, Su L, Ahmad M, Irfan M
    Environ Sci Pollut Res Int, 2021 Oct;28(39):55344-55361.
    PMID: 34137008 DOI: 10.1007/s11356-021-14641-8
    Since the development of the service sector and renewable energy reduce fossil-based energy consumption which mitigates CO2 emissions and this nexus provides a better understanding of the environmental sustainability. Considering the substantially increasing contribution of service sector and tremendous potential for renewable energy in ASEAN5 countries, leaning forward from ASEAN's energy and growth nexus, this study examines the impact of service sector contribution and renewable energy on the environmental quality of ASEAN5 using annual data from 1990 to 2018. The results of the fully modified ordinary least squared, dynamic ordinary least squared, and canonical co-integrating regressions depicted that the service sectors of Thailand, the Philippines, and Singapore augment CO2 emissions; however, the service sectors of Malaysia and Indonesia could reduce CO2 emissions. The increasing share of renewable energy can enhance environmental quality, but its magnitude varies in ASEAN5 economies; non-renewable energy, population, and economic development deteriorate the environment. Our results confirm the existence of environmental Kuznets curve in all the ASEAN5; the Gregory-Hansen test confirmed that results are robust. Finally, the Granger causality designated that economic development and non-renewable energy have a significant causal relationship with CO2 emission of ASEAN5 countries. These findings suggest that the ASEAN5 economies need to optimize their economic structure for promoting sustainable development in the long run.Graphical abstract.
  20. Irfan M, Ghalib SA, Waqas S, Khan JA, Rahman S, Faraj Mursal SN, et al.
    ACS Omega, 2023 May 23;8(20):17869-17879.
    PMID: 37251131 DOI: 10.1021/acsomega.3c00868
    Rice husk ash (RHA), a low-cost biomaterial, was utilized to form bio-oil from pyrolysis in a batch-stirred reactor, followed by its upgradation using the RHA catalyst. In the present study, the effect of temperature (ranging from 400 to 480 °C) on bio-oil production produced from RHA was studied to obtain the maximum bio-oil yield. Response surface methodology (RSM) was applied to investigate the effect of operational parameters (temperature, heating rate, and particle size) on the bio-oil yield. The results showed that a maximum bio-oil output of 20.33% was obtained at 480 °C temperature, 80 °C/min heating rate, and 200 μm particle size. Temperature and heating rate positively impact the bio-oil yield, while particle size has little effect. The overall R2 value of 0.9614 for the proposed model proved in good agreement with the experimental data. The physical properties of raw bio-oil were determined, and 1030 kg/m3 density, 12 MJ/kg calorific value, 1.40 cSt viscosity, 3 pH, and 72 mg KOH/g acid value were obtained, respectively. To enhance the characteristics of the bio-oil, upgradation was performed using the RHA catalyst through the esterification process. The upgraded bio-oil stemmed from a density of 0.98 g/cm3, an acid value of 58 mg of KOH/g, a calorific value of 16 MJ/kg, and a viscosity 10.5 cSt, respectively. The physical properties, GC-MS and FTIR, showed an improvement in the bio-oil characterization. The findings of this study indicate that RHA can be used as an alternative source for bio-oil production to create a more sustainable and cleaner environment.
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