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  1. Bioadsorbent nanocellulose aerogel efficiency impregnated with spent coffee grounds
    Ahmad A, Omar KM, Alahmadi AA, Rizg WY, Bairwan RD, Abdul Khalil HPS
    Int J Biol Macromol, 2024 Feb;258(Pt 1):128746.
    PMID: 38104681 DOI: 10.1016/j.ijbiomac.2023.128746
    Due to growing environmental concerns for better waste management, this study proposes developing a composite aerogel using cellulose nanofibers (CNF) and spent coffee grounds (SCG) through an eco-friendly method for efficient methylene blue (MB) adsorption. Adding SCG to the CNF aerogel altered the physical properties: it increases the volume (4.14 cm3 to 5.25 cm3) and density (0.018 to 0.022 g/cm3) but decrease the water adsorption capacity (2064 % to 1635 %). FTIR spectrum showed distinct functional groups in both all aerogels, showing hydroxyl, glyosidic bonds, and aromatic compounds. Additionally, SCG improved thermal stability of the aerogels. In term of adsorption efficacy, CNF-SCG40% aerogel as exceptionally well. According to Langmuir isotherm models, the adsorption of MB happened in a monolayer, with CNF-SCG40% showing a maximum adsorption capacity of 113.64 mg/g, surpassing CNF aerogel (58.82 mg/g). The study identified that the pseudo-second-order model effectively depicted the adsorption process, indicating a chemical-like interaction. This investigation successfully produced a single-use composite aerogel composed of CNF and SCG using an eco-friendly approach, efficiently adsorbing MB. By utilizing cost-effective materials and eco-friendly methods, this approach offers a sustainable solution for waste management, contributes to an eco-friendly industrial environment, and reduces production expenses and management costs.
  2. Fulltext Clinician resistance to broaching the topic of weight in primary care: Digging deeper into weight management using strong structuration theory
    Hajizadeh A, Heath L, Ahmad A, Kebbe M, Jebb SA, Aveyard P, et al.
    Soc Sci Med, 2023 Jul;329:115997.
    PMID: 37327596 DOI: 10.1016/j.socscimed.2023.115997
    Clinical trials have shown that providing advice and support for people with excess weight can lead to meaningful weight loss. Despite this evidence and guidelines endorsing this approach, provision in real-world clinical settings remains low. We used Strong Structuration Theory (SST) to understand why people are often not offered weight management advice in primary care in England. Data from policy, clinical practice and focus groups were analysed using SST to consider how the interplay between weight stigma and structures of professional responsibilities influenced clinicians to raise (or not) the issue of excess weight with patients. We found that general practitioners (GPs) often accounted for their actions by referring to obesity as a health problem, consistent with policy documents and clinical guidelines. However, they were also aware of weight stigma as a social process that can be internalised by their patients. GPs identified addressing obesity as a priority in their work, but described wanting to care for their patients by avoiding unnecessary suffering, which they were concerned could be caused by talking about weight. We observed tensions between knowledge of clinical guidelines and understanding of the lived experience of their patients. We interpreted that the practice of 'caring by not offering care' produced the outcome of an absence of weight management advice in consultations. There is a risk that this outcome reinforces the external structure of weight stigma as a delicate topic to be avoided, while at the same time denying patients the offer of support to manage their weight.
  3. Intrinsic challenges and strategic approaches for enhancing the potential of natural rubber and its derivatives: A review
    Whba R, Su'ait MS, Whba F, Sahinbay S, Altin S, Ahmad A
    Int J Biol Macromol, 2024 Sep;276(Pt 1):133796.
    PMID: 39004255 DOI: 10.1016/j.ijbiomac.2024.133796
    Natural rubber (NR) and its derivatives play indispensable roles in various industries due to their unique properties and versatile applications. However, the widespread utilization of NR faces intrinsic challenges such as limited mechanical strength, poor resistance to heat and organic solvent, poor electrical conductivity, and low compatibility with other materials, prompting researchers to explore enhancing its performance. Modified NRs (MNRs) like cyclization, deproteinization, chlorination, epoxidation, or grafting NR demonstrated a few enhanced merits compared to NR. However, various strategies, such as blending, vulcanization, crosslinking, grafting, plasticization, reinforcement, and nanostructuring, overcame most drawbacks. This review comprehensively examines these challenges and delves into the modification strategies employed to enhance the properties and expand the applications of NR and its derivatives. Furthermore, the review explores future visions for the NR industry, emphasizing integrating advanced modification techniques, adopting sustainable practices, and promoting circular economy principles. By elucidating the inherent challenges, outlining effective modification strategies, and envisioning future trajectories, this review provides valuable insights for stakeholders seeking to navigate and contribute to the sustainable development of the NR sector.
  4. Immunoinformatics-driven In silico vaccine design for Nipah virus (NPV): Integrating machine learning and computational epitope prediction
    Shahab M, Iqbal MW, Ahmad A, Alshabrmi FM, Wei DQ, Khan A, et al.
    Comput Biol Med, 2024 Mar;170:108056.
    PMID: 38301512 DOI: 10.1016/j.compbiomed.2024.108056
    The Nipah virus (NPV) is a highly lethal virus, known for its significant fatality rate. The virus initially originated in Malaysia in 1998 and later led to outbreaks in nearby countries such as Bangladesh, Singapore, and India. Currently, there are no specific vaccines available for this virus. The current work employed the reverse vaccinology method to conduct a comprehensive analysis of the entire proteome of the NPV virus. The aim was to identify and choose the most promising antigenic proteins that could serve as potential candidates for vaccine development. We have also designed B and T cell epitopes-based vaccine candidate using immunoinformatics approach. We have identified a total of 5 novel Cytotoxic T Lymphocytes (CTL), 5 Helper T Lymphocytes (HTL), and 6 linear B-cell potential antigenic epitopes which are novel and can be used for further vaccine development against Nipah virus. Then we performed the physicochemical properties, antigenic, immunogenic and allergenicity prediction of the designed vaccine candidate against NPV. Further, Computational analysis indicated that these epitopes possessed highly antigenic properties and were capable of interacting with immune receptors. The designed vaccine were then docked with the human immune receptors, namely TLR-2 and TLR-4 showed robust interaction with the immune receptor. Molecular dynamics simulations demonstrated robust binding and good dynamics. After numerous dosages at varied intervals, computational immune response modeling showed that the immunogenic construct might elicit a significant immune response. In conclusion, the immunogenic construct shows promise in providing protection against NPV, However, further experimental validation is required before moving to clinical trials.
  5. Patient Factors in Inappropriate Antibiotic Prescribing for Upper Respiratory Tract Infection in the Emergency Department
    Ahmad A, Nor J, Abdullah AA, Tuan Kamauzaman TH, Yazid MB
    Malays J Med Sci, 2021 Apr;28(2):72-83.
    PMID: 33958962 DOI: 10.21315/mjms2021.28.2.7
    Background: Emergency departments (EDs) are frequently misused for non-emergency cases such as upper respiratory tract infections (URTIs). Flooding of these cases may contribute to inappropriate antibiotic prescribing. The aim of this study was to determine the patient factors associated with inappropriate antibiotic prescribing for URTIs in the EDs.

    Methods: This cross-sectional study involved patients over age 3 years old who presented with URTI to the green zone of the ED of a tertiary hospital on the east coast of Malaysia in 2018-2019. Convenient sampling was done. The patients were categorised into two groups according to their McIsaac scores: positive (≥ 2) or negative (< 2). Antibiotics given to the negative McIsaac group were considered inappropriate.

    Results: A total of 261 cases were included - 127 with positive and 134 with negative McIsaac scores. The most common symptoms were fever and cough. About 29% had inappropriate antibiotic prescribing with a high rate for amoxycillin. Duration of symptoms of one day or less (OR 18.5; 95% CI: 1.65, 207.10; P = 0.018), presence of chills (OR 4.36; 95% CI: 1.13, 16.88; P = 0.033) and diagnosis of acute tonsillitis (OR 5.26; 95% CI: 1.76, 15.72; P = 0.003) were significantly associated with inappropriate antibiotic prescription.

    Conclusion: Factors influencing inappropriate antibiotic prescribing should be pointed out to emergency doctors to reduce its incidence.

  6. Fulltext Serological markers of transfusion transmissible infections and ABO blood groups in Najran, Saudi Arabia
    Alshehri AA, Adebayo Irekeola A, Merae Alshahrani M, Mohammed Abdul KS, Ahmed Asiri S, Aboluluy BF, et al.
    Saudi Med J, 2024 Jul;45(7):667-674.
    PMID: 38955448 DOI: 10.15537/smj.2024.45.7.20240338
    OBJECTIVES: To ascertain the prevalence of transfusion transmissible infections (TTIs) across diverse donor groups in the Najran province. Additionally, to establish a potential association between the development of TTI and the donors' blood group, as determined by the ABO/Rh blood grouping system.

    METHODS: Blood donation data of 4120 donors, spanning from January to December 2020, were retrospectively reviewed. The blood were screened for TTI markers, including hepatitis B surface antigen (HBsAg), anti-hepatitis B core (anti-HBc), anti-hepatitis C virus (anti-HCV), anti-human immunodeficiency viruses 1 and 2 (anti-HIV1&2), anti-human T-lymphotropic virus types 1 and 2 (anti-HTLV-1&2), and syphilis antigen.

    RESULTS: Positive TTI markers were detected in 10.9% of the donors. The most detected TTI marker was anti-HBc (8.9%), followed by HBsAg (0.7%). Other markers were individually detected in <1% of the donors. Anti-HBc-positive was significantly elevated among non-Saudi blood donors. There was an association between age groups and anti-HCV (p=0.002), anti-HTLV (p=0.004) and syphilis antigen (p=0.02) markers positivity. The AB positive blood group exhibited the most positivity for TTI markers, followed by O positive blood group. Similarly, association was found between ABO group and HBsAg (p=0.01), anti-HBc (p=0.001), and anti-HCV (p<0.001) markers positivity.

    CONCLUSION: Emphasis on implementing robust screening measures for donated blood is underscored by this study. There is the need for future study to extensively evaluate TTI status to enhance our understanding of the trend in TTI.

  7. Current and Future Technologies for the Detection of Antibiotic-Resistant Bacteria
    Yamin D, Uskoković V, Wakil AM, Goni MD, Shamsuddin SH, Mustafa FH, et al.
    Diagnostics (Basel), 2023 Oct 18;13(20).
    PMID: 37892067 DOI: 10.3390/diagnostics13203246
    Antibiotic resistance is a global public health concern, posing a significant threat to the effectiveness of antibiotics in treating bacterial infections. The accurate and timely detection of antibiotic-resistant bacteria is crucial for implementing appropriate treatment strategies and preventing the spread of resistant strains. This manuscript provides an overview of the current and emerging technologies used for the detection of antibiotic-resistant bacteria. We discuss traditional culture-based methods, molecular techniques, and innovative approaches, highlighting their advantages, limitations, and potential future applications. By understanding the strengths and limitations of these technologies, researchers and healthcare professionals can make informed decisions in combating antibiotic resistance and improving patient outcomes.
  8. Multi-constituent synergism is responsible for anti-inflammatory effect of Azadirachta indica leaf extract
    Umar MI, Asmawi MZ, Sadikun A, Abdul Majid AM, Atangwho IJ, Khadeer Ahamed MB, et al.
    Pharm Biol, 2014 Nov;52(11):1411-22.
    PMID: 25026347 DOI: 10.3109/13880209.2014.895017
    Azadirachta indica A. Juss. (Meliaceaes) leaves have been used traditionally to treat swelling and rheumatism in Indian cultures.
  9. The potential hazards of Aspergillus sp. in foods and feeds, and the role of biological treatment: a review
    Sheikh-Ali SI, Ahmad A, Mohd-Setapar SH, Zakaria ZA, Abdul-Talib N, Khamis AK, et al.
    J Microbiol, 2014 Oct;52(10):807-18.
    PMID: 25269603 DOI: 10.1007/s12275-014-4294-7
    The contamination of food and feed by Aspergillus has become a global issue with a significant worldwide economic impact. The growth of Aspergillus is unfavourable to the development of food and feed industries, where the problems happen mostly due to the presence of mycotoxins, which is a toxic metabolite secreted by most Aspergillus groups. Moreover, fungi can produce spores that cause diseases, such as allergies and asthma, especially to human beings. High temperature, high moisture, retarded crops, and poor food storage conditions encourage the growth of mold, as well as the development of mycotoxins. A variety of chemical, biological, and physical strategies have been developed to control the production of mycotoxins. A biological approach, using a mixed culture comprised of Saccharomyces cerevisiae and Lactobacillus rhamnosus resulted in the inhibition of the growth of fungi when inoculated into fermented food. The results reveal that the mixed culture has a higher potential (37.08%) to inhibit the growth of Aspergillus flavus (producer of Aflatoxin) compared to either single culture, L. rhamnosus NRRL B-442 and S. cerevisiae, which inhibit the growth by 63.07% and 64.24%, respectively.
  10. Renal denervation restores the baroreflex control of renal sympathetic nerve activity and heart rate in Wistar-Kyoto rats with cisplatin-induced renal failure
    Khan SA, Sattar MA, Rathore HA, Abdulla MH, Ud Din Ahmad F, Ahmad A, et al.
    Acta Physiol (Oxf), 2014 Mar;210(3):690-700.
    PMID: 24438102 DOI: 10.1111/apha.12237
    There is evidence that in chronic renal failure, the sympathetic nervous system is activated. This study investigated the role of the renal innervation in suppressing high- and low-pressure baroreflex control of renal sympathetic nerve activity and heart rate in cisplatin-induced renal failure.
  11. Effects of the total alkaloidal extract of Murraya koenigii leaf on oxidative stress and cholinergic transmission in aged mice
    Mani V, Ramasamy K, Ahmad A, Wahab SN, Jaafar SM, Kek TL, et al.
    Phytother Res, 2013 Jan;27(1):46-53.
    PMID: 22447662 DOI: 10.1002/ptr.4676
    Alzheimer's disease (AD) is characterized by signs of major oxidative stress and the loss of cholinergic cells. The present study was designed to investigate the role of the total alkaloidal extract from Murraya koenigii (MKA) leaves on age related oxidative stress and the cholinergic pathway in aged mice. Ascorbic acid (100 mg/kg, p.o.) was used as a standard drug. The MKA improved the level of protective antioxidants such as glutathione peroxidase (GPx), reduced glutathione (GSH), glutathione reductase (GRD), superoxide dismutase (SOD) and catalase (CAT) in brain homogenate at higher doses (20 and 40 mg/kg, p.o.). Moreover, a dose dependent decline was noted in lipid peroxidation (LPO) and the nitric oxide assay (NO) at all doses of MKA (10, 20 and 40 mg/kg, p.o.). Interestingly, significant progress was noted with the supplementation of MKA by an improvement of the acetylcholine (ACh) levels and a reduction in the acetylcholinesterase (AChE) activity in aged mouse brain. In addition, a significant elevation of serum albumin (ALBU), alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST) and total protein as well as a decline in creatinine, total cholesterol, urea nitrogen and glucose levels with MKA also ameliorated the hepatic and renal functions in normal ageing process. The results showed the possible utility of Murraya koenigii leaves in neuroprotection against neurodegenerative disorders such as Alzheimer's disease.
  12. Fulltext Reliability, technical error of measurements and validity of length and weight measurements for children under two years old in Malaysia
    Jamaiyah H, Geeta A, Safiza MN, Khor GL, Wong NF, Kee CC, et al.
    Med J Malaysia, 2010 Jun;65 Suppl A:131-7.
    PMID: 21488474
    The National Health and Morbidity Survey III 2006 wanted to perform anthropometric measurements (length and weight) for children in their survey. However there is limited literature on the reliability, technical error of measurement (TEM) and validity of these two measurements. This study assessed the above properties of length (LT) and weight (WT) measurements in 130 children age below two years, from the Hospital Universiti Kebangsaan Malaysia (HUKM) paediatric outpatient clinics, during the period of December 2005 to January 2006. Two trained nurses measured WT using Tanita digital infant scale model 1583, Japan (0.01kg) and Seca beam scale, Germany (0.01 kg) and LT using Seca measuring mat, Germany (0.1cm) and Sensormedics stadiometer model 2130 (0.1cm). Findings showed high inter and intra-examiner reliability using 'change in the mean' and 'intraclass correlation' (ICC) for WT and LT. However, LT was found to be less reliable using the 'Bland and Altman plot'. This was also true using Relative TEMs, where the TEM value of LT was slightly more than the acceptable limit. The test instruments were highly valid for WT using 'change in the mean' and 'ICC' but was less valid for LT measurement. In spite of this we concluded that, WT and LT measurements in children below two years old using the test instruments were reliable and valid for a community survey such as NHMS III within the limits of their error. We recommend that LT measurements be given special attention to improve its reliability and validity.
    Study site: Paediatric clinic, Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM), Kuala Lumpur, Malaysia
  13. Physiological characteristics of elite and sub-elite badminton players
    Ooi CH, Tan A, Ahmad A, Kwong KW, Sompong R, Ghazali KA, et al.
    J Sports Sci, 2009 Dec;27(14):1591-9.
    PMID: 19967588 DOI: 10.1080/02640410903352907
    The aims of this study were to establish the physical and physiological attributes of elite and sub-elite Malaysian male badminton players and to determine whether these attributes discriminate elite players from sub-elite players. Measurements and tests of basic anthropometry, explosive power, anaerobic recovery capacity, badminton-specific movement agility, maximum strength, and aerobic capacity were conducted on two occasions, separated by at least one day. The elite (n = 12) and sub-elite (n = 12) players' characteristics were, respectively: mean age 24.6 years (s = 3.7) and 20.5 years (s = 0.7); mass 73.2 kg (s = 7.6) and 62.7 kg (s = 4.2); stature 1.76 m (s = 0.07) and 1.71 m (s = 0.05); body fat 12.5% (s = 4.8) and 9.5% (s = 3.4); estimated VO(2max) 56.9 ml . kg(-1) . min(-1) (s = 3.7) and 59.5 ml . kg(-1) . min(-1) (s = 5.2). The elite players had greater maximum absolute strength in one-repetition maximum bench press (P = 0.015) compared with the sub-elite players. There were significant differences in instantaneous lower body power estimated from vertical jump height between the elite and sub-elite groups (P < 0.01). However, there was no significant difference between groups in shuttle run tests and on-court badminton-specific movement agility tests. Our results show that elite Malaysian male badminton players are taller, heavier, and stronger than their sub-elite counterparts. The test battery, however, did not allow us to discriminate between the elite and sub-elite players, suggesting that at the elite level tactical knowledge, technical skills, and psychological readiness could be of greater importance.
  14. Coordinate systems integration for development of malaysian craniofacial database
    Rajion Z, Suwardhi D, Setan H, Chong A, Majid Z, Ahmad A, et al.
    Conf Proc IEEE Eng Med Biol Soc, 2007 2 7;2005:5112-5.
    PMID: 17281397
    This study presents a data registration method for craniofacial spatial data of different modalities. The data consists of three dimensional (3D) vector and raster data models. The data is stored in object relational database. The data capture devices are Laser scanner, CT (Computed Tomography) scan and CR (Close Range) Photogrammetry. The objective of the registration is to transform the data from various coordinate systems into a single 3-D Cartesian coordinate system. The standard error of the registration obtained from multimodal imaging devices using 3D affine transformation is in the ranged of 1-2 mm. This study is a step forward for storing the spatial craniofacial data in one reference system in database.
  15. Fulltext Evaluation of Potential Drug-Drug Interactions with Antidepressants in Two Tertiary Care Hospitals
    Rafi MS, Naqvi SB, Khan MU, Fayyaz M, Ashraf N, Khan MA, et al.
    J Clin Diagn Res, 2015 Jul;9(7):FC05-8.
    PMID: 26393139 DOI: 10.7860/JCDR/2015/13437.6207
    Limited resources of healthcare system and high use of antidepressants have raised some serious concerns regarding proper surveillance system of prescribed medicines. Not much literature is available from Pakistan regarding the potential drug-drug interactions (pDDIs) associated with antidepressants.
  16. Immunomodulatory Effect of Cytokines in the Differentiation of Mesenchymal Stem Cells: A Review
    Zahari W, Hashim SN, Yusof MF, Osman ZF, Kannan TP, Mokhtar KI, et al.
    Curr Stem Cell Res Ther, 2017;12(3):197-206.
    PMID: 27306400 DOI: 10.2174/1574888X11666160614103404
    Mesenchymal stem cells (MSCs) are stromal origin cells with multilineage differentiation capacity. The immunoregulatory properties of MSCs can be interfered effectively by cytokines. Cytokines, produced by a broad range of cells, act at the systemic level to influence biological phenomena such as inflammation, wound healing, organogenesis and oncogenesis. Cytokines also play vital roles in the differentiation of MSCs into several cell lineages. This review summarizes on how cytokines can affect MSCs differentiation and their relative signaling pathways, which may serve to understand the possible underlying mechanisms. Also, this review reveals the potential clinical use of MSCs as promising therapeutic agents due to their special characteristics such as multipotent differentiation, immunomodulatory properties, and selfrestoration.
  17. Fulltext Cystathione gamma lyase/Hydrogen Sulphide Pathway Up Regulation Enhances the Responsiveness of α1A and α1B-Adrenoreceptors in the Kidney of Rats with Left Ventricular Hypertrophy
    Ahmad A, Sattar MA, Azam M, Abdulla MH, Khan SA, Hashmi F, et al.
    PLoS One, 2016;11(5):e0154995.
    PMID: 27191852 DOI: 10.1371/journal.pone.0154995
    The purpose of the present study was to investigate the interaction between H2S and NO (nitric oxide) in the kidney and to evaluate its impact on the functional contribution of α1A and α1B-adrenoreceptors subtypes mediating the renal vasoconstriction in the kidney of rats with left ventricular hypertrophy (LVH). In rats the LVH induction was by isoprenaline administration and caffeine in the drinking water together with intraperitoneal administration of H2S. The responsiveness of α1A and α1B to exogenous noradrenaline, phenylephrine and methoxaminein the absence and presence of 5-methylurapidil (5-MeU) and chloroethylclonidine (CEC) was studied. Cystathione gamma lyase (CSE), cystathione β synthase (CBS), 3-mercaptopyruvate sulphar transferase (3-MST) and endothelial nitric oxide synthase (eNOS) were quantified. There was significant up regulation of CSE and eNOS in the LVH-H2S compared to the LVH group (P<0.05). Baseline renal cortical blood perfusion (RCBP) was increased (P<0.05) in the LVH-H2S compared to the LVH group. The responsiveness of α1A-adrenergic receptors to adrenergic agonists was increased (P<0.05) after administration of low dose 5-Methylurapidil in the LVH-H2S group while α1B-adrenergic receptors responsiveness to adrenergic agonists were increased (P<0.05) by both low and high dose chloroethylclonidine in the LVH-H2S group. Treatment of LVH with H2S resulted in up-regulation of CSE/H2S, CBS, and 3-MST and eNOS/NO/cGMP pathways in the kidney. These up regulation of CSE/H2S, CBS, and 3-MST and eNOS/NO/cGMP pathways enhanced the responsiveness of α1A and α1B-adrenoreceptors subtypes to adrenergic agonists in LVH-H2S. These findings indicate an important role for H2S in modulating deranged signalling in the renal vasculature resulting from LVH development.
  18. Fulltext Knowledge, awareness, and perception of contraception among senior pharmacy students in Malaysia: A pilot study
    Elkalmi RM, Khan MU, Ahmad A, Srikanth AB, Abdurhaman NS, Jamshed SQ, et al.
    J Res Pharm Pract, 2015 Apr-Jun;4(2):94-8.
    PMID: 25984548 DOI: 10.4103/2279-042X.155760
    OBJECTIVE:This study aimed to assess the knowledge, awareness, and perception of contraception among senior pharmacy students of a public sector university in Malaysia.
    METHODS: A cross-sectional, questionnaire-based study was conducted among senior pharmacy students. The pretested questionnaire was used to collect data from the participants over the period of 1-month. The questionnaire was divided into four sections, for gathering the information about students' demographic data, and their knowledge, attitudes, and perception toward contraception. Data were statistically analyzed using SPSS version 20.
    FINDINGS: The response rate was 68.6%. The results showed that the contraceptive knowledge was comparatively higher in year four students (P < 0.001), married respondents (P < 0.001) and those taking elective courses (P = 0.022) as compared to their respective counterparts. Majority of the students were well aware and had a positive perception about contraception.
    CONCLUSION: Overall findings reflect that the majority of the students had good knowledge, perception, and awareness about contraception. The study recommends future studies to be conducted covering different pharmacy schools across the country to further establish the results.
    KEYWORDS: Awareness; contraceptive; knowledge; perception; students
  19. Fulltext Effect of Sand Fines Concentration on the Erosion-Corrosion Mechanism of Carbon Steel 90° Elbow Pipe in Slug Flow
    Khan R, H Ya H, Pao W, Majid MAA, Ahmed T, Ahmad A, et al.
    Materials (Basel), 2020 Oct 16;13(20).
    PMID: 33081078 DOI: 10.3390/ma13204601
    Erosion-corrosion of elbow configurations has recently been a momentous concern in hydrocarbon processing and transportation industries. The carbon steel 90° elbows are susceptible to the erosion-corrosion during the multiphase flow, peculiarly for erosive slug flows. This paper studies the erosion-corrosion performance of 90° elbows at slug flow conditions for impact with 2, 5, and 10 wt.% sand fines concentrations on AISI 1018 carbon steel exploiting quantitative and qualitative analyses. The worn surface analyses were effectuated by using laser confocal and scanning electron microscopy. The experiment was conducted under air and water slug flow containing sand fines of 50 µm average size circulated in the closed flow loop. The results manifest that with the increase of concentration level, the erosion-corrosion magnitude increases remarkably. Sand fines instigate the development of perforation sites in the form of circular, elongated, and coalescence pits at the elbow downstream and the corrosion attack is much more obvious with the increase of sand fines concentration. Another congruent finding is that cutting and pitting corrosion as the primitive causes of material degradation, the 10 wt.% sand fines concentration in carrier phase increases the erosion-corrosion rate of carbon steel up to 93% relative to the 2 wt.% sand fines concentration in slug flow.
  20. Insights into the Current Trends in the Utilization of Bacteria for Microbially Induced Calcium Carbonate Precipitation
    Chuo SC, Mohamed SF, Mohd Setapar SH, Ahmad A, Jawaid M, Wani WA, et al.
    Materials (Basel), 2020 Nov 05;13(21).
    PMID: 33167607 DOI: 10.3390/ma13214993
    Nowadays, microbially induced calcium carbonate precipitation (MICP) has received great attention for its potential in construction and geotechnical applications. This technique has been used in biocementation of sand, consolidation of soil, production of self-healing concrete or mortar, and removal of heavy metal ions from water. The products of MICP often have enhanced strength, durability, and self-healing ability. Utilization of the MICP technique can also increase sustainability, especially in the construction industry where a huge portion of the materials used is not sustainable. The presence of bacteria is essential for MICP to occur. Bacteria promote the conversion of suitable compounds into carbonate ions, change the microenvironment to favor precipitation of calcium carbonate, and act as precipitation sites for calcium carbonate crystals. Many bacteria have been discovered and tested for MICP potential. This paper reviews the bacteria used for MICP in some of the most recent studies. Bacteria that can cause MICP include ureolytic bacteria, non-ureolytic bacteria, cyanobacteria, nitrate reducing bacteria, and sulfate reducing bacteria. The most studied bacterium for MICP over the years is Sporosarcina pasteurii. Other bacteria from Bacillus species are also frequently investigated. Several factors that affect MICP performance are bacterial strain, bacterial concentration, nutrient concentration, calcium source concentration, addition of other substances, and methods to distribute bacteria. Several suggestions for future studies such as CO2 sequestration through MICP, cost reduction by using plant or animal wastes as media, and genetic modification of bacteria to enhance MICP have been put forward.
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