Browse publications by year: 2020

  1. Mohammed AA, Haris SM, Al Azzawi W
    Sci Rep, 2020 Jul 29;10(1):12676.
    PMID: 32728209 DOI: 10.1038/s41598-020-69387-z
    In this paper, the acoustic impedance property has been employed to predict the ultimate tensile strength (UTS) and yield strength (YS) of pure metals and alloys. Novel algorithms were developed, depending on three experimentally measured parameters, and programmed in a MATLAB code. The measured parameters are longitudinal wave velocity of the metal, density, and crystal structure. 19-samples were considered in the study and divided into 3-groups according to their crystal structure; 7-FCC, 6-BCC, and 6-HCB. X-ray diffraction was used to examine the crystal structure of each sample of each group, while longitudinal wave velocity and metals' density were measured experimentally. A comparison between mechanical properties predicted by the model and the ASTM standards was done to investigate the validity of the model. Furthermore, predicted stress-strain curves were compared with corresponding curves in the pieces literature as an additional validation check. The results revealed the excellence of the model with 85-99% prediction accuracy. The study also proved that if metals are grouped according to their crystal structure, a relation between UTS, YS, and modulus of elasticity (E) properties and wave pressure transmission coefficient (Tr) could be formulated.
  2. Eh Suk VR, Mohd Latif F, Teo YY, Misran M
    J Food Sci Technol, 2020 Sep;57(9):3259-3266.
    PMID: 32728274 DOI: 10.1007/s13197-020-04357-x
    Lipid nanocarrier displays the advantages over conventional drug carriers as they are formulated with biodegradable and non-irritant lipids. However, the main drawbacks are the agglomeration of lipid particles, instability over storage, low drug loading, and the burst release of active ingredients. In this study, we investigated the effects of various polysorbate nonionic surfactants namely Tween 20, 40, 60, or 80 on the nanostructured lipid carrier (NLC). NLC incorporated with polysorbate nonionic surfactant was prepared by using high-pressure homogenization technique. The average size was reduced to 139.9 ± 15.8 nm in the presence of Tween 80 and remained stable in nano-size even incubated for 28 days. Encapsulation of l-ascorbic acid or Gold Tri.E 30 showed a high encapsulation efficiency of more than 75%, where the highest was Gold Tri.E in the presence of Tween 60 at 99.7%. In vitro release study showed that the release of both l-ascorbic acid and Gold Tri.E was significantly reduced in NLC with Tween as compared to bare active ingredients and NLC without Tween. In conclusion, the incorporation of Tween successfully produced a lipid nanocarrier that has the potential to be developed as a carrier of various active ingredients such as nutrients, extracts, and drugs.
  3. Johan S, Lee PP, Azizan N, Hayati F, Zakaria AD
    Oxf Med Case Reports, 2020 Jul;2020(7):omaa050.
    PMID: 32728453 DOI: 10.1093/omcr/omaa050
    Intestinal obstruction is a common surgical emergency requiring urgent intervention. Small bowel obstruction secondary to intussusception is rarely encountered especially when inflammatory fibroid polyp (IFP) is the lead point. A 41-year-old gentleman with intestinal intussusception secondary to IFP presented to us with a classic symptom of intestinal obstruction. Computed tomography revealed a target or sausage-shaped soft tissue mass with a layering effect, which was confirmed by intraoperative findings. Histopathology was consistent with IFP and supported by immunoreactivity of CD34 and negative immunostaining for CD117. He recovered without any surgical complication or recurrence. Even intussusception can be managed via non-surgical technique in children; surgery is the mainstay of treatment in adults.
  4. Sulaiman NFC, Akhir NHM, Hussain NE, Jamin RM, Ramli NH
    Data Brief, 2020 Aug;31:106018.
    PMID: 32728602 DOI: 10.1016/j.dib.2020.106018
    This data article presents the impact of parents' socioeconomic status on undergraduate students' academic achievements at a Malaysian higher education institution. The eastern parts of Peninsular Malaysia are populated by low-income citizens compared to the national average. The survey was conducted in Universiti Malaysia Terengganu. The targeted population is final year social science students. The total size of the target population is 965 students. Using Krejcie and Morgan's sampling method, a sample size of 333 students was surveyed. A descriptive research design was adopted in this study. Data were obtained from stratified random sampling comprising a total of 333 respondents in Universiti Malaysia Terengganu from 14 states across Malaysia. The data were collected through a semi-structured questionnaire. Data analysis was carried out using tables and figures. The findings revealed that most of the students stated that a parent's socioeconomic status does not influence their academic achievement.
    MeSH terms: Humans; Malaysia; Poverty; Surveys and Questionnaires; Social Class; Students; Sample Size
  5. Ashigar MA, Ab Majid AH
    Data Brief, 2020 Aug;31:106037.
    PMID: 32728606 DOI: 10.1016/j.dib.2020.106037
    Metagenomic datasets of the microbial DNA of workers of a Pheidole decarinata Santschi (Hymenoptera: Formicidae) around houses with three replicates were presented. Next-generation sequencing of the microbial DNA was performed on an Illumina Miseq platform. QIIME (version 1.9.1) was used to analyze the raw fastq files. Metagenome of the three (3) samples consist of 333,708 sequences representing 137,359,149 bps with an average length of 413.67 bps. The sequence data is available at the NCBI SRA with the bioproject number PRJNA632430. Community analysis revealed Proteobacteria was the predominant (84.77%) microbial community present in the microbial DNA of workers of the P. decarinata.
    MeSH terms: Animals; Ants; DNA; Humans; Proteobacteria; Metagenome; High-Throughput Nucleotide Sequencing; Microbiota
  6. Sharma M, Prasher P, Mehta M, Zacconi FC, Singh Y, Kapoor DN, et al.
    Drug Dev Res, 2020 Jul 30.
    PMID: 32729640 DOI: 10.1002/ddr.21724
  7. Li JJ, Liu HH, Wu NQ, Yeo KK, Tan K, Ako J, et al.
    Expert Opin Drug Metab Toxicol, 2020 Sep;16(9):837-851.
    PMID: 32729743 DOI: 10.1080/17425255.2020.1802426
    INTRODUCTION: Statins have been established as the standard of care for dyslipidemia and preventing cardiovascular diseases while posing few safety concerns. However, misconceptions about statin intolerance lead to their underuse, indicating a need to improve the understanding of the safety of this treatment.

    AREAS COVERED: We searched PubMed and reviewed literatures related to statin intolerance published between February 2015 and February 2020. Important large-scale or landmark studies published before 2015 were also cited as key evidence.

    EXPERT OPINION: Optimal lowering of low-density lipoprotein cholesterol with statins substantially reduces the risk of cardiovascular events. Muscle adverse events (AEs) were the most frequently reported AEs by statin users in clinical practice, but they usually occurred at a similar rate with statins and placebo in randomized controlled trials and had a spurious causal relationship with statin treatment. We proposed a rigorous definition for identifying true statin intolerance and present the criteria for defining different forms of muscle AEs and an algorithm for their management. True statin intolerance is uncommon, and every effort should be made to exclude false statin intolerance and ensure optimal use of statins. For the management of statin intolerance, statin-based approaches should be prioritized over non-statin approaches.

    MeSH terms: Algorithms; Cardiovascular Diseases/etiology; Cardiovascular Diseases/prevention & control; Humans; Cholesterol, LDL/blood; Muscular Diseases/chemically induced*; Muscular Diseases/diagnosis; Hydroxymethylglutaryl-CoA Reductase Inhibitors/administration & dosage*; Hydroxymethylglutaryl-CoA Reductase Inhibitors/adverse effects; Dyslipidemias/complications; Dyslipidemias/drug therapy*
  8. Wong LP, Alias H, Wong PF, Lee HY, AbuBakar S
    Hum Vaccin Immunother, 2020 09 01;16(9):2204-2214.
    PMID: 32730103 DOI: 10.1080/21645515.2020.1790279
    BACKGROUND: The development of a vaccine against SARS-CoV-2 infection is on the way. To prepare for public availability, the acceptability of a hypothetical COVID-19 vaccine and willingness to pay (WTP) were assessed to provide insights into future demand forecasts and pricing considerations.

    METHODS: A cross-sectional survey was conducted from 3 to 12 April 2020. The health belief model (HBM) was used to assess predictors of the intent to receive the vaccine and the WTP.

    RESULTS: A total of 1,159 complete responses was received. The majority reported a definite intent to receive the vaccine (48.2%), followed by a probable intent (29.8%) and a possible intent (16.3%). Both items under the perceived benefits construct in the HBM, namely believe the vaccination decreases the chance of infection (OR = 2.51, 95% CI 1.19-5.26) and the vaccination makes them feel less worry (OR = 2.19, 95% CI 1.03-4.65), were found to have the highest significant odds of a definite intention to take the vaccine. The mean ± standard deviation (SD) for the amount that participants were willing to pay for a dose of COVID-19 vaccine was MYR$134.0 (SD±79.2) [US$30.66 ± 18.12]. Most of the participants were willing to pay an amount of MYR$100 [US$23] (28.9%) and MYR$50 [US$11.5] (27.2%) for the vaccine. The higher marginal WTP for the vaccine was influenced by no affordability barriers as well as by socio-economic factors, such as higher education levels, professional and managerial occupations and higher incomes.

    CONCLUSIONS: The findings demonstrate the utility of HBM constructs in understanding COVID-19 vaccination intention and WTP.

    MeSH terms: Adolescent; Adult; Aged; Cross-Sectional Studies; Health Expenditures; Female; Humans; Malaysia/epidemiology; Male; Middle Aged; Models, Psychological; Patient Acceptance of Health Care/statistics & numerical data*; Pneumonia, Viral/prevention & control; Socioeconomic Factors; Vaccination/economics; Vaccination/psychology*; Viral Vaccines/economics; Coronavirus Infections/economics; Coronavirus Infections/prevention & control; Coronavirus Infections/psychology; Health Care Surveys; Young Adult; Pandemics/prevention & control
  9. Christofferson RC, Parker DM, Overgaard HJ, Hii J, Devine G, Wilcox BA, et al.
    PLoS Negl Trop Dis, 2020 Jul;14(7):e0008302.
    PMID: 32730249 DOI: 10.1371/journal.pntd.0008302
    MeSH terms: Animals; Congresses as Topic; Dengue/epidemiology; Dengue/prevention & control; Dengue/transmission*; Health Priorities; Humans; Insect Vectors*; Malaria/epidemiology; Malaria/prevention & control; Malaria/transmission*; Mekong Valley/epidemiology; Vaccines*
  10. Seth EA, Lee HC, Yusof HHBM, Nordin N, Cheah YK, Ho ETW, et al.
    PLoS One, 2020;15(7):e0236826.
    PMID: 32730314 DOI: 10.1371/journal.pone.0236826
    Down syndrome (DS), is the most common cause of intellectual disability, and is characterized by defective neurogenesis during perinatal development. To identify metabolic aberrations in early neurogenesis, we profiled neurospheres derived from the embryonic brain of Ts1Cje, a mouse model of Down syndrome. High-throughput phenotypic microarray revealed a significant decrease in utilisation of 17 out of 367 substrates and significantly higher utilisation of 6 substrates in the Ts1Cje neurospheres compared to controls. Specifically, Ts1Cje neurospheres were less efficient in the utilisation of glucose-6-phosphate suggesting a dysregulation in the energy-producing pathway. T Cje neurospheres were significantly smaller in diameter than the controls. Subsequent preliminary study on supplementation with 6-phosphogluconic acid, an intermediate of glucose-6-phosphate metabolism, was able to rescue the Ts1Cje neurosphere size. This study confirmed the perturbed pentose phosphate pathway, contributing to defects observed in Ts1Cje neurospheres. We show for the first time that this comprehensive energetic assay platform facilitates the metabolic characterisation of Ts1Cje cells and confirmed their distinguishable metabolic profiles compared to the controls.
    MeSH terms: Animals; Brain/embryology; Brain/metabolism; Brain/pathology*; Down Syndrome/metabolism; Down Syndrome/pathology*; Female; Mice, Inbred C57BL; Neurons/metabolism*; Neurons/pathology*; Phenotype; Microarray Analysis; Mice; Neurogenesis*
  11. Adil M, Mohd Zaid H, Raza F, Agam MA
    PLoS One, 2020;15(7):e0236837.
    PMID: 32730369 DOI: 10.1371/journal.pone.0236837
    Recent developments propose renewed use of surface-modified nanoparticles (NPs) for enhanced oil recovery (EOR) due to improved stability and reduced porous media retention. The enhanced surface properties render the nanoparticles more suitable compared to bare nanoparticles, for increasing the displacement efficiency of waterflooding. However, the EOR mechanisms using NPs are still not well established. This work investigates the effect of in-situ surface-modified silica nanoparticles (SiO2 NPs) on interfacial tension (IFT) and wettability behavior as a prevailing oil recovery mechanism. For this purpose, the nanoparticles have been synthesized via a one-step sol-gel method using surface-modification agents, including Triton X-100 (non-ionic surfactant) and polyethylene glycol (polymer), and characterized using various techniques. These results exhibit the well-defined spherical particles, particularly in the presence of Triton X-100 (TX-100), with particle diameter between 13 to 27 nm. To this end, SiO2 nanofluids were formed by dispersing nanoparticles (0.05 wt.%, 0.075 wt.%, 0.1 wt.%, and 0.2 wt.%) in 3 wt.% NaCl to study the impact of surface functionalization on the stability of the nanoparticle suspension. The optimal stability conditions were obtained at 0.1 wt.% SiO2 NPs at a basic pH of 10 and 9.5 for TX-100/ SiO2 and PEG/SiO nanofluids, respectively. Finally, the surface-treated SiO2 nanoparticles were found to change the wettability of treated (oil-wet) surface into water-wet by altering the contact angle from 130° to 78° (in case of TX-100/SiO2) measured against glass surface representing carbonate reservoir rock. IFT results also reveal that the surfactant treatment greatly reduced the oil-water IFT by 30%, compared to other applied NPs. These experimental results suggest that the use of surface-modified SiO2 nanoparticles could facilitate the displacement efficiency by reducing IFT and altering the wettability of carbonate reservoir towards water-wet, which is attributed to more homogeneity and better dispersion of surface-treated silica NPs compared to bare-silica NPs.
    MeSH terms: Oils/analysis; Oils/isolation & purification*; Oils/chemistry; Silicon Dioxide/chemistry*; Surface Tension; Surface-Active Agents/chemistry*; Wettability; Nanoparticles/chemistry*
  12. Alshagga MA, Mohamed Z, Seyedan A, Ebling FJP, Alshawsh MA
    J Ethnopharmacol, 2020 Nov 15;262:113187.
    PMID: 32730892 DOI: 10.1016/j.jep.2020.113187
    ETHNOPHARMACOLOGICAL RELEVANCE: Khat (Catha edulis (Vahl) Forssk.) is a herb from the Celastraceae family (also known as qat, gaad, or mirra) that is widely-consumed in East Africa and in the Arabian peninsula. The green leaves and small stems are consumed primarily at recreational and social gatherings, and medicinally for their antidiabetic and appetite-suppression effects.

    AIMS: The objectives of this study were to determine the effects of khat and its active alkaloid, cathinone, on food intake and body weight in mice maintained on a high-fat diet, and to investigate its mechanism of action in white adipose tissue and in the hypothalamus.

    MATERIALS & METHOD: Adult male mice (C57BL/6J) were fed a high fat diet (HFD) for 8 weeks (n = 30), then divided into 5 groups and treated daily for a further 8 weeks with HFD + vehicle [control (HFD)], HFD + 15 mg/kg orlistat (HFDO), HFD + 200 mg/kg khat extract (HFDK200), HFD + 400 mg/kg khat extract (HFDK400) and HFD + 3.2 mg/kg cathinone (HFDCAT). Treatments were carried out once daily by gastric gavage. Blood and tissue samples were collected for biochemical, hormonal and gene expression analyses.

    RESULTS: Khat extracts and orlistat treatment significantly reduced weight gain as compared to control mice on HFD, and cathinone administration completely prevented weight gain in mice fed on HFD. Khat treatment caused a marked reduction in body fat and in serum triglycerides. A dose-dependent effect of khat was observed in reducing serum leptin concentrations. Analysis of gene expression in adipose tissue revealed a significant upregulation of two lipolysis pathway genes:(adipose triglyceride lipase (PNPLA-2) and hormone-sensitive lipase (LIPE). In the hypothalamic there was a significant (P 

    MeSH terms: Animals; Body Weight/drug effects; Body Weight/physiology; Eating/drug effects; Eating/genetics; Lipolysis/drug effects*; Lipolysis/physiology; Male; Mice, Inbred C57BL; Obesity/drug therapy; Obesity/genetics*; Obesity/metabolism; Plant Extracts/isolation & purification; Plant Extracts/pharmacology; Plant Extracts/therapeutic use*; Up-Regulation/drug effects; Up-Regulation/physiology; Catha*; Mice; Adipose Tissue, White/drug effects*; Adipose Tissue, White/metabolism; Diet, High-Fat/adverse effects*
  13. Aye AMM, Bai X, Borrow R, Bory S, Carlos J, Caugant DA, et al.
    J Infect, 2020 11;81(5):698-711.
    PMID: 32730999 DOI: 10.1016/j.jinf.2020.07.025
    The degree of surveillance data and control strategies for invasive meningococcal disease (IMD) varies across the Asia-Pacific region. IMD cases are often reported throughout the region, but the disease is not notifiable in some countries, including Myanmar, Bangladesh and Malaysia. Although there remains a paucity of data from many countries, specific nations have introduced additional surveillance measures. The incidence of IMD is low and similar across the represented countries (<0.2 cases per 100,000 persons per year), with the predominant serogroups of Neisseria meningitidis being B, W and Y, although serogroups A and X are present in some areas. Resistance to ciprofloxacin is also of concern, with the close monitoring of antibiotic-resistant clonal complexes (e.g., cc4821) being a priority. Meningococcal vaccination is only included in a few National Immunization Programs, but is recommended for high-risk groups, including travellers (such as pilgrims) and people with complement deficiencies or human immunodeficiency virus (HIV). Both polysaccharide and conjugate vaccines form part of recommendations. However, cost and misconceptions remain limiting factors in vaccine uptake, despite conjugate vaccines preventing the acquisition of carriage.
    MeSH terms: Asia/epidemiology; Bangladesh; Myanmar; Humans; Neisseria meningitidis*; Meningococcal Vaccines*; Serogroup
  14. Tuan DD, Hung C, Da Oh W, Ghanbari F, Lin JY, Lin KA
    Chemosphere, 2020 Dec;261:127552.
    PMID: 32731015 DOI: 10.1016/j.chemosphere.2020.127552
    As cobalt (Co) represents an effective transition metal for activating Oxone to degrade contaminants, tricobalt tetraoxide (Co3O4) is extensively employed as a heterogeneous phase of Co for Oxone activation. Since Co3O4 can be manipulated to exhibit various shapes, 2-dimensional plate-like morphology of Co3O4 can offer large contact surfaces. If the large plate-like surfaces can be even porous, forming porous nanoplate Co3O4 (PNC), such a PNC should be a promising catalyst for Oxone activation. Therefore, a facile but straightforward method is proposed to prepare such a PNC for activating Oxone to degrade pollutants. In particular, a cobaltic coordination polymer with a morphology of hexagonal nanoplate, which is synthesized through coordination between Co2+ and thiocyanuric acid (TCA), is adopted as a precursor. Through calcination, CoTCA could be transformed into hexagonal nanoplate-like Co3O4 with pores to become PNC. This PNC also shows different characteristics from the commercial Co3O4 nanoparticle (NP) in terms of surficial reactivity and textural properties. Thus, PNC exhibits a much higher catalytic activity than the commercial Co3O4 NP towards activation of Oxone to degrade a model contaminant, salicylic acid (SA). Specifically, SA was 100% degraded by PNC activating Oxone within 120 min, and the Ea of SA degradation by PNC-activated Oxone is 70.2 kJ/mol. PNC can also remain stable and effective for SA degradation even in the presence of other anions, and PNC could be reused over multiple cycles without significant loss of catalytic activity. These features validate that PNC is a promising and useful Co-based catalyst for Oxone activation.
    MeSH terms: Catalysis; Cobalt/chemistry*; Oxides/chemistry*; Polymers; Sulfuric Acids; Water; Water Pollutants, Chemical/analysis*; Porosity; Water Purification/methods*
  15. Mohd Razali, Othman, Nor Mazlina, Ghazali, Suraida, Abdullah, Mohd Izzat Syafiq, Mohd Razali
    MyJurnal
    The aim of this study is to develop and assess the validity and reliability of Employee Needs Assessment Inventory (ENAI). Employee Needs Assessment Inventory (ENAI) aims to screen employees’ problem and measured eight scale namely health, financial, family, spiritual, work, career, interpersonal relationship and work environment. The instrument is developed based on Ecological Theory by Bronfenbrenner (1979). The questionnaire is distributed to 1113 employees in selected public university in Malaysia. The reliability of the instrument is measured using internal consistence reliability (Cronbach Alpha). The construct validity is measured by Exploratory Factor Analysis (EFA). The result indicated a coefficient alpha is 0.96 for the 76 ENAI items. The coefficient alphas for the eight subscales were as follows: 0.89 for health, 0.79 for financial, 0.86 for family, 0.83 for spiritual, 0.88 for work, 0.85 for career, 0.90 for interpersonal relationship and 0.89 for work environment. The study founds the instrument is valid and reliable.
  16. Asnarulkhadi, Abu Samah, Akmar Hayati, Ahmad Ghazali, Siti Zobidah, Omar, Haslinda, Abdullah, Aminah, Ahmad, Hayrol Azril, Mohamed Shaffril
    MyJurnal
    Cyberbullying has emerged of late as a serious issue, especially among the most active internet users in Malaysia – youths. As the number of related studies is still lacking, the present study aims to determine the predictors of cyberbullying among youths in Malaysia. The study is quantitative in nature and in total had involved 400 youths aged between 18 to 40 years old. The findings suggest that predictors such as age, loneliness, self-esteem, and empathy yielded significant relationship with cyberbullying, while males were predominantly reported to perpetrate cyberbullying than females. Several recommendations were highlighted and hopefully, it can assist any concerned parties in developing concrete strategies to reduce cyberbullying cases among youths in Malaysia further.
  17. Abdullah UYH, Ibrahim HM, Mahmud NB, Salleh MZ, Teh LK, Noorizhab MNFB, et al.
    Hemoglobin, 2020 May;44(3):184-189.
    PMID: 32586164 DOI: 10.1080/03630269.2020.1781652
    Effective prevention of β-thalassemia (β-thal) requires strategies to detect at-risk couples. This is the first study attempting to assess the prevalence of silent β-thal carriers in the Malaysian population. Hematological and clinical parameters were evaluated in healthy blood donors and patients with β-thal trait, Hb E (HBB: c.79G>A)/β-thal and β-thal major (β-TM). β-Globin gene sequencing was carried out for 52 healthy blood donors, 48 patients with Hb E/β-thal, 34 patients with β-TM and 38 patients with β-thal trait. The prevalence of silent β-thal carrier phenotypes found in 25.0% of healthy Malaysian blood donors indicates the need for clinician's awareness of this type in evaluating β-thal in Malaysia. Patients with β-TM present at a significantly younger age at initial diagnosis and require more blood transfusions compared to those with Hb E/β-thal. The time at which genomic DNA was extracted after blood collection, particularly from patients with β-TM and Hb E/β-thal, was found to be an important determinant of the quality of the results of the β-globin sequencing. Public education and communication campaigns are recommended as apparently healthy individuals have few or no symptoms and normal or borderline hematological parameters. β-Globin gene mutation characterization and screening for silent β-thal carriers in regions prevalent with β-thal are recommended to develop more effective genetic counseling and management of β-thal.
    MeSH terms: Alleles; Chromatography, High Pressure Liquid; Cross-Sectional Studies; Erythrocyte Indices; Genetic Counseling*; Genotype*; Hemoglobin E/genetics; Humans; Malaysia/epidemiology; Mutation*; Phenotype*; Polymerase Chain Reaction; beta-Thalassemia/blood; beta-Thalassemia/diagnosis; beta-Thalassemia/genetics*; beta-Thalassemia/epidemiology*; beta-Globins/genetics*; Genetic Association Studies*; Public Health Surveillance
  18. Samsudin MFR, Frebillot C, Kaddoury Y, Sufian S, Ong WJ
    J Environ Manage, 2020 Sep 15;270:110803.
    PMID: 32721291 DOI: 10.1016/j.jenvman.2020.110803
    To maximize the employment of sustainable solar energy in treating the recalcitrant pollutant and hydrogen energy production, the development of a highly efficient photocatalyst is desirable. Herein, a Z-scheme Ag/AgVO3/g-C3N4 photocatalyst was synthesized via a wet-impregnation method. The amount of Ag/AgVO3 deposited onto g-C3N4 has a significant effect on the photocharge carrier separation and migration of the as-developed Z-scheme photocatalyst. It was found that 0.5 wt % Ag/AgVO3/g-C3N4 photocatalyst exhibited a profound photocatalytic degradation performance with 82.6% ciprofloxacin removal and 3.57 mmol/h of hydrogen produced from natural rainwater under visible-light irradiation. Additionally, the apparent quantum efficiency (AQE) of this sample was 9.95% at 420 nm which is four times higher than the pure sample. The remarkable photocatalytic performance was attributed to the enhanced crystallographic structure, evidently from the XRD and XPS analysis. Moreover, the intimate contact between Ag/AgVO3 and g-C3N4 nanoparticles allows the smooth photocharge carrier separation and migrations, resulting in superior photocatalytic performance in comparison to the pure samples. Interestingly, the profound photocatalytic activity demonstrated here was achieved without the addition of any sacrificial reagents. This work demonstrates the feasibility of utilizing visible-light-driven photocatalysts in treating the recalcitrant antibiotic pollutants and producing hydrogen from natural rainwater.
    MeSH terms: Catalysis; Ciprofloxacin*; Hydrogen; Light; Silver*
  19. Mengting Z, Kurniawan TA, Yanping Y, Dzarfan Othman MH, Avtar R, Fu D, et al.
    J Environ Manage, 2020 Sep 15;270:110839.
    PMID: 32721303 DOI: 10.1016/j.jenvman.2020.110839
    We aim at fabricating a ternary magnetic recyclable Bi2WO6/BiOI@Fe3O4 composite that could be applied for photodegradation of tetracycline (TC) from synthetic wastewater. To identify any changes with respect to the composite's morphology and crystal structure properties, ΧRD, FTIR, FESEM-EDS, PL and VSM analyses are carried out. The effects of Fe3O4 loading ratio on the Bi2WO6/BiOI for TC photodegradation are evaluated, while operational parameters such as pH, reaction time, TC concentration, and photocatalyst's dose are optimized. Removal mechanisms of the TC by the composite and its photodegradation pathways are elaborated. With respect to its performance, under the same optimized conditions (1 g/L of dose; 5 mg/L of TC; pH 7; 3 h of reaction time), the Bi2WO6/BiOI@5%Fe3O4 composite has the highest TC removal (97%), as compared to the Bi2WO6 (63%). After being saturated, the spent photocatalyst could be magnetically separated from solution for subsequent use. In spite of three consecutive cycles with 71% of efficiency, the spent composite still has reasonable photocatalytic activities for reuse. Overall, this suggests that the composite is a promising photocatalyst for TC removal from aqueous solutions.
    MeSH terms: Anti-Bacterial Agents*; Magnetics; Photolysis; Tetracycline*; Magnetic Phenomena
  20. Kurniawan TA, Mengting Z, Fu D, Yeap SK, Othman MHD, Avtar R, et al.
    J Environ Manage, 2020 Sep 15;270:110871.
    PMID: 32721315 DOI: 10.1016/j.jenvman.2020.110871
    Methylene blue is a refractory pollutant commonly present in textile wastewater. This study tests the feasibility of TiO2/graphene oxide (GO) composite in enhancing photocatalytic degradation of MB in synthetic wastewater with respect to scientific and engineering aspects. To enhance its removal, we vary the composition of the composite based on the TiO2 weight. Under UV-vis irradiation, the effects of photocatalyst's dose, pH, and reaction time on MB removal by the composites are evaluated under optimum conditions, while any changes in their physico-chemical properties before and after treatment are analyzed by using TEM, SEM, XRD, FTIR and BET. The photodegradation pathways of the target pollutant by the composite and its removal mechanisms are also elaborated. It is found that the same composite with a 1:2 wt ratio of GO/TiO2 has the largest surface area of 104.51 m2/g. Under optimum reactions (0.2 g/L of dose, pH 10, and 5 mg/L of pollutant's concentration), an almost complete MB removal could be attained within 4 h. This result is higher than that of the TiO2 alone (30%) under the same conditions. Since the treated effluents could meet the strict discharge standard limit of ≤0.2 μg/L set by China's regulation, subsequent biological treatments are unnecessary for completing biodegradation of remaining oxidation by-products in the wastewater effluents.
    MeSH terms: Catalysis; Graphite; Methylene Blue*; Titanium; Waste Water*
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