Browse publications by year: 2021

  1. Fulltext Proteomic Signature of Dysfunctional Circulating Endothelial Colony-Forming Cells of Young Adults
    Tan CMJ, Lewandowski AJ, Williamson W, Huckstep OJ, Yu GZ, Fischer R, et al.
    J Am Heart Assoc, 2021 Aug 03;10(15):e021119.
    PMID: 34275329 DOI: 10.1161/JAHA.121.021119
    Background A subpopulation of endothelial progenitor cells called endothelial colony-forming cells (ECFCs) may offer a platform for cellular assessment in clinical studies because of their remarkable angiogenic and expansion potentials in vitro. Despite endothelial cell function being influenced by cardiovascular risk factors, no studies have yet provided a comprehensive proteomic profile to distinguish functional (ie, more angiogenic and expansive cells) versus dysfunctional circulating ECFCs of young adults. The aim of this study was to provide a detailed proteomic comparison between functional and dysfunctional ECFCs. Methods and Results Peripheral blood ECFCs were isolated from 11 subjects (45% men, aged 27±5 years) using Ficoll density gradient centrifugation. ECFCs expressed endothelial and progenitor surface markers and displayed cobblestone-patterned morphology with clonal and angiogenic capacities in vitro. ECFCs were deemed dysfunctional if <1 closed tube formed during the in vitro tube formation assay and proliferation rate was <20%. Hierarchical functional clustering revealed distinct ECFC proteomic signatures between functional and dysfunctional ECFCs with changes in cellular mechanisms involved in exocytosis, vesicle transport, extracellular matrix organization, cell metabolism, and apoptosis. Targeted antiangiogenic proteins in dysfunctional ECFCs included SPARC (secreted protein acidic and rich in cysteine), CD36 (cluster of differentiation 36), LUM (lumican), and PTX3 (pentraxin-related protein PYX3). Conclusions Circulating ECFCs with impaired angiogenesis and expansion capacities have a distinct proteomic profile and significant phenotype changes compared with highly angiogenic endothelial cells. Impaired angiogenesis in dysfunctional ECFCs may underlie the link between endothelial dysfunction and cardiovascular disease risks in young adults.
    MeSH terms: Adult; Serum Amyloid P-Component/analysis; C-Reactive Protein/analysis; Cells, Cultured; Exocytosis; Female; Humans; Male; Osteonectin/analysis; Neovascularization, Physiologic*; Antigens, CD36/analysis; Proteomics/methods; Cell Proliferation*; Transcriptome/physiology*; Lumican/analysis
  2. Fulltext Health System Governance for the Integration of Mental Health Services into Primary Health Care in the Sub-Saharan Africa and South Asia Region: A Systematic Review
    Abd Rahim A, Abdul Manaf R, Juni MH, Ibrahim N
    Inquiry, 2021 7 20;58:469580211028579.
    PMID: 34275346 DOI: 10.1177/00469580211028579
    Governance has been highlighted as an important building block underpinning the process of mental health integration into primary healthcare. This qualitative systematic review aims to identify the governance issues faced by countries in the Sub-Saharan Africa and South Asia Region in the implementation of integrated primary mental healthcare. PRISMA guideline was used to conduct a systematic search of relevant studies from 4 online databases that were filtered according to inclusion and exclusion criteria. Using the Critical Appraisal Skills Program (CASP) Qualitative Checklist, a quality appraisal of the selected articles was performed. By drawing upon institutional theory, data was extracted based on a pre-constructed matrix. The CERQual approach synthesized evidence and rank confidence level as low, moderate or high for 5 key findings. From 567 references identified, a total of 8 studies were included. Respondents were policymakers or implementers involved in integrated primary mental healthcare from the national, state, and district level. Overall, the main governance issues identified were a lack of leadership and mental health prioritization; inadequate financing and human resource capacity; and negative mental health perceptions/attitudes. The implication of the findings is that such issues must be addressed for long-term health system performance. This can also improve policymaking for better integration of primary mental health services into the health systems of countries in the Sub-Saharan and South Asia region.
  3. Fulltext Molecular detection of Theileria species, Anaplasma species, Candidatus Mycoplasma haemobos, Trypanosoma evansi and first evidence of Theileria sinensis-associated bovine anaemia in crossbred Kedah-Kelantan x Brahman cattle
    Agina OA, Shaari MR, Isa NMM, Ajat M, Zamri-Saad M, Mazlan M, et al.
    BMC Vet Res, 2021 Jul 18;17(1):246.
    PMID: 34275459 DOI: 10.1186/s12917-021-02902-0
    BACKGROUND: Serious disease outbreaks in cattle are usually associated with blood pathogens. This study aims to detect blood pathogens namely Theileria species, Anaplasma species, Candidatus Mycoplasma haemobos and Trypanosoma evansi, and determine their phylogenetic relationships and haemato-biochemical abnormalities in naturally infected cattle.

    METHODS: Molecular analysis was achieved by PCR amplification and sequencing of PCR amplicons of 18SrRNA gene of Theileria species, 16SrRNA genes of Anaplasma and Mycoplasma species, MPSP genes of T. orientalis and T. sinensis, MSP4 gene of A. marginale, 16SrRNA gene of Candidatus Mycoplasma haemobos, and RoTat1.2 VSG gene of Trypanosoma evansi, in sixty-one (61) clinically ill Kedah-Kelantan x Brahman cattle in Pahang, Malaysia.

    RESULTS: A total of 44 (72.13%) cattle were infected with more than one blood pathogen. Theileria species was the blood pathogen with the highest molecular detection rate (72.13, 95% CI 59.83-81.81%). Nucleotide blast analyses of all sequences demonstrated high degree of molecular similarity (98-100%) in comparison with their respective reference sequences. Analysis of 18SrRNA gene sequences of Theileria species and 16SrRNA gene sequences of Anaplasma species revealed Theileria sinensis and Anaplasma platys respectively as additional species detected in these cattle. MPSP-PCR analysis was conducted for further confirmation of T. sinensis. The blood picture of eight infected cattle groups revealed poikilocytosis, anisocytosis, rouleaux formation and degenerative left shift. High mean erythrocyte fragility values were common in infected cattle groups. Anaemia of the macrocytic normochromic type and spherocytes were observed in the T. evansi and Anaplasma platys + Theileria sinensis double species co-infected cattle group. Normocytic normochromic anaemia was observed in the T. sinensis infected cattle group. Significant (p 

    MeSH terms: Anaplasma/genetics; Anaplasma/isolation & purification; Anaplasmosis/epidemiology; Anemia/parasitology; Anemia/veterinary*; Animals; Cattle; Cattle Diseases/blood; Cattle Diseases/microbiology; Cattle Diseases/epidemiology*; Cattle Diseases/parasitology; Female; Malaysia; Male; Mycoplasma/genetics; Mycoplasma/isolation & purification; Mycoplasma Infections/epidemiology; Mycoplasma Infections/veterinary; Theileriasis/blood; Theileriasis/epidemiology*; Trypanosoma/genetics; Trypanosoma/isolation & purification; Trypanosomiasis/epidemiology; Trypanosomiasis/veterinary; Theileria/genetics; Theileria/isolation & purification
  4. Fulltext Pharmacy preparedness in handling COVID-19 pandemic: a sharing experience from a Malaysian tertiary hospital
    Thong KS, Selvaratanam M, Tan CP, Cheah MF, Oh HL, Lee PM, et al.
    J Pharm Policy Pract, 2021 Jul 19;14(1):61.
    PMID: 34275491 DOI: 10.1186/s40545-021-00343-6
    This commentary shares the experience of a hospital pharmacy department in providing healthcare services during the COVID-19 outbreak in Malaysia. During this pandemic, the medication delivery system is redesigned to minimize contact among patients and the health care providers. Also, the remote medication monitoring system was implemented to deliver pharmaceutical care for inpatients. Communication technology was used to assist the pharmacist in medication counseling. QR codes to access videos demonstrating the use of devices were made available for patients. Pharmacists were also tasked with the procurement of personal protective equipment and medications needed requiring special approval from the Ministry of Health.
  5. Letter to the editor concerning "Time to surgery: Is it truly crucial in initially stable patients with penetrating injury?"
    Chen TH, Hsiao CH, Hsieh SL, Shin SD, Jamaluddin SF, Chiang WC, et al.
    Injury, 2021 11;52(11):3528-3529.
    PMID: 34275643 DOI: 10.1016/j.injury.2021.07.003
  6. Synthesis, spectral analysis and biological evaluation of 2-{[(morpholin-4-yl)ethyl]thio}-5-phenyl/aryl-1,3,4-oxadiazole derivatives
    Ur-Rehman A, Khan SG, Naqvi SAR, Ahmad M, Akhtar N, Bokhari TH, et al.
    Pak J Pharm Sci, 2021 Jan;34(1(Special)):441-446.
    PMID: 34275792
    A series of new derivatives of 4-(2-chloroethyl)morpholine hydrochloride (5) were efficiently synthesized. Briefly, different aromatic organic acids (1a-f) were refluxed to acquire respective esters (2a-f) using conc. H2SO4 as catalyst. The esters were subjected to nucleophillic substitution by monohydrated hydrazine to acquire hydrazides (3a-f). The hydrazides were cyclized with CS2 in the presence of KOH to yield corresponding oxadiazoles (4a-f). Finally, the derivatives, 6a-f, were prepared by reacting oxadiazoles (4a-f) with 5 using NaH as activator. Structures of all the derivatives were elucidated through 1D-NMR EI-MS and IR spectral data. All these molecules were subjected to antibacterial and hemolytic activities and showed good antibacterial and hemolytic potential relative to the reference standards.
    MeSH terms: Anti-Bacterial Agents/chemical synthesis; Anti-Bacterial Agents/pharmacology; Anti-Bacterial Agents/chemistry*; Bacillus subtilis/drug effects; Escherichia coli/drug effects; Klebsiella pneumoniae/drug effects; Morpholines/chemical synthesis; Morpholines/pharmacology; Morpholines/chemistry*; Magnetic Resonance Spectroscopy; Oxadiazoles/chemical synthesis; Oxadiazoles/pharmacology; Oxadiazoles/chemistry*; Pseudomonas aeruginosa/drug effects; Salmonella typhi/drug effects; Spectrophotometry, Infrared; Mass Spectrometry; Staphylococcus aureus/drug effects; Hemolytic Agents/chemical synthesis; Hemolytic Agents/pharmacology; Hemolytic Agents/chemistry*
  7. Fulltext Systems-thinking approach to identify and assess feasibility of potential interventions to reduce antibiotic use in tilapia farming in Egypt
    Desbois AP, Garza M, Eltholth M, Hegazy YM, Mateus A, Adams A, et al.
    Aquaculture, 2021 Jul 15;540:736735.
    PMID: 34276104 DOI: 10.1016/j.aquaculture.2021.736735
    Antibiotics are used in aquaculture to maintain the health and welfare of stocks; however, the emergence and selection of antibiotic resistance in bacteria poses threats to humans, animals and the environment. Mitigation of antibiotic resistance relies on understanding the flow of antibiotics, residues, resistant bacteria and resistance genes through interconnecting systems, so that potential solutions can be identified and issues around their implementation evaluated. Participatory systems-thinking can capture the deep complexity of a system while integrating stakeholder perspectives. In this present study, such an approach was applied to Nile tilapia (Oreochromis niloticus) production in the Nile Delta of Egypt, where disease events caused by antibiotic-resistant pathogens have been reported. A system map was co-produced with aquaculture stakeholders at a workshop in May 2018 and used to identify hotspots of antibiotic use, exposure and fate and to describe approaches that would promote fish health and thus reduce antibiotic use. Antibiotics are introduced into the aquaculture system via direct application for example in medicated feed, but residues may also be introduced into the system through agricultural drainage water, which is the primary source of water for most fish farms in Egypt. A follow-up survey of stakeholders assessed the perceived feasibility, advantages and disadvantages of potential interventions. Interventions that respondents felt could be implemented in the short-term to reduce antibiotic usage effectively included: more frequent water exchanges, regular monitoring of culture water quality parameters, improved storage conditions for feed, use of probiotics and greater access to farmer and service providers training programmes. Other potential interventions included greater access to suitable and rapid diagnostics, high quality feeds, improved biosecurity measures and genetically-improved fish, but these solutions were expected to be achieved as long-term goals, with cost being of one of the noted barriers to implementation. Identifying feasible and sustainable interventions that can be taken to reduce antibiotic use, and understanding implementation barriers, are important for addressing antibiotic resistance and ensuring the continued efficacy of antibiotics. This is vital to ensuring the productivity of the tilapia sector in Egypt. The approach taken in the present study provides a means to identify points in the system where the effectiveness of interventions can be evaluated and thus it may be applied to other food production systems to combat the problem of antibiotic resistance.
  8. Fulltext Atypical Antipsychotic Lumateperone Effects on the Adrenal Gland With Possible Beneficial Effect of Quercetin Co-administration
    El-Haroun H, Ewida SF, Mohamed WMY, Bashandy MA
    Front Physiol, 2021;12:674550.
    PMID: 34276400 DOI: 10.3389/fphys.2021.674550
    Schizophrenia remains one of the most chronic and highly disabling mental disorders. Lumateperone is a recent FDA-approved atypical antipsychotic drug for the treatment of schizophrenia. However, the internal FDA pathologist raised concerns regarding pigment deposition associated with degeneration in different tissue in animal studies with lumateperone treatment. The adrenal gland may be implicated in lumateperone side effects, and quercetin may have the ability to fulfill this treatment gap. To prove this hypothesis, 40 male guinea pigs were used and divided into four groups; control, quercetin-treated, lumateperone-treated, and quercetin/lumateperone cotreated orally for 28 consecutive days. Behavioral forced swim (FST) and open field (OF) tests were done at the end of treatment. Retro-orbital blood samples were taken to assess hormones: adrenocorticotropic hormone (ACTH), cortisol, dehydroepiandrosterone acetate (DHEA), and aldosterone, along with an assessment of oxidative stress parameters: malondialdehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD). Adrenal glands were extracted for histopathological assessment with H&E, Mallory trichome staining, immunostaining, and electron microscopy studies. Lumateperone-treated group showed a significant reduction in the activity in FST and OF with histopathological deterioration in adrenal secretory function and structure and increased expression of interleukin-6 (IL-6), CASPASE-3, collagen deposition, and decreased proliferating cell nuclear antigen (PCNA). Cytoplasmic vacuolation, pyknosis of the nuclei, increase in the lysosome, lipofuscin pigment, and cellular infiltration with diminishing in the number of secretory granules could all be observed in lumateperone-treated group. Coadministration of quercetin and lumateperone showed improvement of the previously deteriorated parameters. Quercetin had a prophylactic effect against lumateperone depressive-like effect on animal behavior and its possible adrenal damage. Graphical AbstractConceptual framework for the proposed mechanism of action of coadministration of quercetin and lumateperone.
  9. Fulltext Metabolite Profiling of Malaysian Gracilaria edulis Reveals Eplerenone as Novel Antibacterial Compound for Drug Repurposing Against MDR Bacteria
    Asghar A, Tan YC, Shahid M, Yow YY, Lahiri C
    Front Microbiol, 2021;12:653562.
    PMID: 34276590 DOI: 10.3389/fmicb.2021.653562
    With a continuous threat of antimicrobial resistance on human health worldwide, efforts for new alternatives are ongoing for the management of bacterial infectious diseases. Natural products of land and sea, being conceived to be having fewer side effects, pose themselves as a welcome relief. In this respect, we have taken a scaffolded approach to unearthing the almost unexplored chemical constituents of Malaysian red seaweed, Gracilaria edulis. Essentially, a preliminary evaluation of the ethyl acetate and acetone solvent extracts, among a series of six such, revealed potential antibacterial activity against six MDR species namely, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella enterica, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, and Bacillus subtilis. Detailed analyses of the inlying chemical constituents, through LC-MS and GC-MS chromatographic separation, revealed a library of metabolic compounds. These were led for further virtual screening against selected key role playing proteins in the virulence of the aforesaid bacteria. To this end, detailed predictive pharmacological analyses added up to reinforce Eplerenone as a natural alternative from the plethora of plausible bioactives. Our work adds the ongoing effort to re-discover and repurpose biochemical compounds to combat the antimicrobial resistance offered by the Gram-positive and the -negative bacterial species.
  10. Fulltext Alginate and alginate composites for biomedical applications
    Ahmad Raus R, Wan Nawawi WMF, Nasaruddin RR
    Asian J Pharm Sci, 2021 May;16(3):280-306.
    PMID: 34276819 DOI: 10.1016/j.ajps.2020.10.001
    Alginate is an edible heteropolysaccharide that abundantly available in the brown seaweed and the capsule of bacteria such as Azotobacter sp. and Pseudomonas sp. Owing to alginate gel forming capability, it is widely used in food, textile and paper industries; and to a lesser extent in biomedical applications as biomaterial to promote wound healing and tissue regeneration. This is evident from the rising use of alginate-based dressing for heavily exuding wound and their mass availability in the market nowadays. However, alginate also has limitation. When in contact with physiological environment, alginate could gelate into softer structure, consequently limits its potential in the soft tissue regeneration and becomes inappropriate for the usage related to load bearing body parts. To cater this problem, wide range of materials have been added to alginate structure, producing sturdy composite materials. For instance, the incorporation of adhesive peptide and natural polymer or synthetic polymer to alginate moieties creates an improved composite material, which not only possesses better mechanical properties compared to native alginate, but also grants additional healing capability and promote better tissue regeneration. In addition, drug release kinetic and cell viability can be further improved when alginate composite is used as encapsulating agent. In this review, preparation of alginate and alginate composite in various forms (fibre, bead, hydrogel, and 3D-printed matrices) used for biomedical application is described first, followed by the discussion of latest trend related to alginate composite utilization in wound dressing, drug delivery, and tissue engineering applications.
  11. Fulltext Rare late-presentation congenital diaphragmatic hernia mimicking a tension pneumothorax
    Muien MZA, Jeyaprahasam K, Krisnan T, Ng CY, Teh YG
    Radiol Case Rep, 2021 Sep;16(9):2542-2545.
    PMID: 34276850 DOI: 10.1016/j.radcr.2021.06.024
    Congenital Diaphragmatic Hernia (CDH) is due to a defect in the diaphragm and is usually detected soon after birth. However, in rare cases, asymptomatic CDHs can be missed and present later in life. Late-presentation CDH can be misdiagnosed as tension pneumothorax leading to iatrogenic complications. We report a case of a 10-year-old boy who presented with non-specific symptoms of vomiting and occasional breathlessness, but was subsequently diagnosed as late-presentation CDH. This case highlights the role of imaging in the diagnosis and management of late-presenting CDH. The role of CT imaging as an invaluable tool to further evaluate equivocal radiographic findings in CDH is discussed.
  12. Fulltext Acute Proptosis in a Diabetic Patient: Diagnostic and Therapeutic Dilemmas
    Khairul-Anwar I, Tai E, Hussein A, Zunaina E
    Cureus, 2021 Jun;13(6):e15580.
    PMID: 34277202 DOI: 10.7759/cureus.15580
    An elderly diabetic lady presented with a painful swollen right eye and blurred vision for one week, preceded by right eye redness for six months. Her right eye best-corrected visual acuity was finger counting at 1 m. There was right eye proptosis, limited extraocular muscle movements, corkscrew vessels, chemosis and elevated intraocular pressure, but no bruit. Fever was absent. Computed tomography of the brain and orbit showed thickened extraocular muscles and intraconal fat streakiness, with normal superior ophthalmic vein and concavity of the cavernous sinus. Intravenous antibiotics resulted in limited clinical improvement. The subsequent response to oral prednisolone was dramatic, with the improvement of visual acuity to 20/60 after three doses. In cases of atypical orbital cellulitis where antibiotics fail, one should consider differential diagnoses such as orbital inflammatory disease, vascular anomalies and masqueraders. We discuss the approach to the diagnosis of acute proptosis in a diabetic patient and highlight the role of corticosteroids in idiopathic orbital inflammatory disease.
  13. Fulltext Study Protocol for a Global Survey: Awareness and Preparedness of Hospital Staff Against Coronavirus Disease (COVID-19) Outbreak
    Qarawi ATA, Ng SJ, Gad A, Luu MN, Al-Ahdal TMA, Sharma A, et al.
    Front Public Health, 2021;9:580427.
    PMID: 34277529 DOI: 10.3389/fpubh.2021.580427
    Background: The outbreak of Coronavirus disease (COVID-19) caused by a novel coronavirus (named SARS-CoV-2) has gained attention globally and has been recognized as a Public Health Emergency of International Concern (PHEIC) by the World Health Organization (WHO) due to the rapidly increasing number of deaths and confirmed cases. Health care workers (HCWs) are vulnerable to this crisis as they are the first frontline to receive and manage COVID-19 patients. In this multicenter multinational survey, we aim to assess the level of awareness and preparedness of hospital staff regarding COVID-19 all over the world. Methods: From February to March 2020, the web-based or paper-based survey to gather information about the hospital staff's awareness and preparedness in the participants' countries will be carried out using a structured questionnaire based on the United States Centers for Disease Control and Prevention (CDC) checklist and delivered to participants by the local collaborators for each hospital. As of March 2020, we recruited 374 hospitals from 58 countries that could adhere to this protocol as approved by their Institutional Review Boards (IRB) or Ethics Committees (EC). Discussion: The awareness and preparedness of HCWs against COVID-19 are of utmost importance not only to protect themselves from infection, but also to control the virus transmission in healthcare facilities and to manage the disease, especially in the context of manpower lacking and hospital overload during the pandemic. The results of this survey can be used to inform hospitals about the awareness and preparedness of their health staff regarding COVID-19, so appropriate policies and practice guidelines can be implemented to improve their capabilities of facing this crisis and other future pandemic-prone diseases.
    MeSH terms: Disease Outbreaks/prevention & control; Humans; Personnel, Hospital; United States; Multicenter Studies as Topic; Pandemics
  14. Fulltext Effectiveness of a Novel Smartphone Health Education Intervention in Enhancing Knowledge, Attitudes, and Practices for the Prevention of Respiratory Tract Infections Among Private Hajj Pilgrims From Malaysia
    Goni MD, Naing NN, Hasan H, Wan-Arfah N, Deris ZZ, Arifin WN, et al.
    Front Public Health, 2021;9:594204.
    PMID: 34277530 DOI: 10.3389/fpubh.2021.594204
    This study was aimed to develop and evaluate the efficacy of a health education program for increasing knowledge, changing attitudes, and promoting prevention practices to reduce the incidence of RTIs among Malaysian Hajj pilgrims. A quasi-experimental study was done among 130 Hajj pilgrims attending Hajj orientation course organized by a private Hajj tour companies. Hajj pilgrims assigned to intervention group (n = 65) and control group (n = 65). Data were collected baseline and after return from Hajj using a validated questionnaire. Mixed design repeated measure ANOVA was used to analyse the effect of group, time, and group-time interaction on the dependent variables. There was a significant improvement in knowledge, attitude and practice scores in the intervention group compared to the control group. Based on the findings of the interaction of time and group, there was a significant statistical difference for post intervention for knowledge (p = 0.005), attitude (p = 0.041), and practice (p = 0.002). The newly-established health education intervention smartphone application was effective in improving KAP toward RTIs prevention among pilgrims.
    MeSH terms: Smartphone; Health Education; Humans; Islam*; Health Knowledge, Attitudes, Practice; Malaysia/epidemiology; Travel
  15. Fulltext Impoverishment of the Poor and Derogation of Human Rights During the Covid-19 Pandemic in Indonesia: Testing the Emergency Measure and Siracusa Principles in Large-Scale Social Restriction
    Tampubolon M
    J Hum Rights Soc Work, 2021 Jul 13.
    PMID: 34277928 DOI: 10.1007/s41134-021-00174-0
    This study examines human rights restrictions in the Large-Scale Social Restrictions (or PSBB) during the Covid-19 outbreak in Indonesia that do not follow the Siracusa Principles emergency measure and limitation clause. PSBB resulted in a prolonged human rights crisis due to ineffective policies, manipulated data, and inadequate medical equipment. The author discusses the impact of Large-Scale Social Restrictions on socio-economic and socio-political rights and the government's failure to overcome the Covid-19 outbreak with an interdisciplinary perspective. Findings from studies on the number of Covid-19 cases contracted and the high mortality rate are also presented. This study notes the consequences and the relationship between the ineffectiveness of Large-Scale Social Restrictions and human misery.
  16. Fulltext Managing supraglottitis in the COVID-19 era
    Sahril S, Narayanan MS, Mohamad I
    Vis J Emerg Med, 2021 Jul;24:101092.
    PMID: 34277997 DOI: 10.1016/j.visj.2021.101092
  17. Fulltext Fast and Cost-Effective Mathematical Models for Hydrocarbon-Immiscible Water Alternating Gas Incremental Recovery Factor Prediction
    Belazreg L, Mahmood SM, Aulia A
    ACS Omega, 2021 Jul 13;6(27):17492-17500.
    PMID: 34278135 DOI: 10.1021/acsomega.1c01901
    Predicting the incremental recovery factor with an enhanced oil recovery (EOR) technique is a very crucial task. It requires a significant investment and expert knowledge to evaluate the EOR incremental recovery factor, design a pilot, and upscale pilot result. Water-alternating-gas (WAG) injection is one of the proven EOR technologies, with an incremental recovery factor typically ranging from 5 to 10%. The current approach of evaluating the WAG process, using reservoir modeling, is a very time-consuming and costly task. The objective of this research is to develop a fast and cost-effective mathematical model for evaluating hydrocarbon-immiscible WAG (HC-IWAG) incremental recovery factor for medium-to-light oil in undersaturated reservoirs, designing WAG pilots, and upscaling pilot results. This integrated research involved WAG literature review, WAG modeling, and selected machine learning techniques. The selected machine learning techniques are stepwise regression and group method of data handling. First, the important parameters for the prediction of the WAG incremental recovery factor were selected. This includes reservoir properties, rock and fluid properties, and WAG injection scheme. Second, an extensive WAG and waterflood modeling was carried out involving more than a thousand reservoir models. Third, WAG incremental recovery factor mathematical predictive models were developed and tested, using the group method of data handling and stepwise regression techniques. HC-IWAG incremental recovery factor mathematical models were developed with a coefficient of determination of about 0.75, using 13 predictors. The developed WAG predictive models are interpretable and user-friendly mathematical formulas. These developed models will help the subsurface teams in a variety of ways. They can be used to identify the best candidates for WAG injection, evaluate and optimize the WAG process, help design successful WAG pilots, and facilitate the upscaling of WAG pilot results to full-field scale. All this can be accomplished in a short time at a low cost and with reasonable accuracy.
  18. Fulltext Associations between the indoor microbiome, environmental characteristics and respiratory infections in junior high school students of Johor Bahru, Malaysia
    Fu X, Yuan Q, Zhu X, Li Y, Meng Y, Hashim JH, et al.
    Environ Sci Process Impacts, 2021 Aug 01;23(8):1171-1181.
    PMID: 34278392 DOI: 10.1039/d1em00115a
    Pathogens are commonly present in the human respiratory tract, but symptoms are varied among individuals. The interactions between pathogens, commensal microorganisms and host immune systems are important in shaping the susceptibility, development and severity of respiratory diseases. Compared to the extensive studies on the human microbiota, few studies reported the association between indoor microbiome exposure and respiratory infections. In this study, 308 students from 21 classrooms were randomly selected to survey the occurrence of respiratory infections in junior high schools of Johor Bahru, Malaysia. Vacuum dust was collected from the floor, chairs and desks of these classrooms, and high-throughput amplicon sequencing (16S rRNA and ITS) and quantitative PCR were conducted to characterize the absolute concentration of the indoor microorganisms. Fifteen bacterial genera in the classes Actinobacteria, Alphaproteobacteria, and Cyanobacteria were protectively associated with respiratory infections (p < 0.01), and these bacteria were mainly derived from the outdoor environment. Previous studies also reported that outdoor environmental bacteria were protectively associated with chronic respiratory diseases, such as asthma, but the genera identified were different between acute and chronic respiratory diseases. Four fungal genera from Ascomycota, including Devriesia, Endocarpon, Sarcinomyces and an unclassified genus from Herpotrichillaceae, were protectively associated with respiratory infections (p < 0.01). House dust mite (HDM) allergens and outdoor NO2 concentration were associated with respiratory infections and infection-related microorganisms. A causal mediation analysis revealed that the health effects of HDM and NO2 were partially or fully mediated by the indoor microorganisms. This is the first study to explore the association between environmental characteristics, microbiome exposure and respiratory infections in a public indoor environment, expanding our understanding of the complex interactions among these factors.
    MeSH terms: Dust/analysis; Humans; Malaysia/epidemiology; RNA, Ribosomal, 16S; Schools; Students; Microbiota*
  19. Aptasensing luteinizing hormone to determine gynecological endocrine complications on graphene oxide layered sensor
    Sun H, Bao X, Yao X, Gopinath SCB, Min Y
    Biotechnol Appl Biochem, 2021 Jul 18.
    PMID: 34278604 DOI: 10.1002/bab.2223
    Luteinizing hormone (LH)/Lutropin is an interstitial cell stimulating hormone playing a predominant role in the reproductive system, and highly correlated with the infertility treatment in both men and women. This research was concentrated to quantify LH level by using interdigitated electrode sensor. To improve the electric current flow, sensing electrode was modified with graphene oxide (GO) and the aptamer probe was attached on GO through biotin-streptavidin linker. Current responses were measured with aptamer-LH interaction at the target concentrations between 7.5 nM and 1 μM and the detection limit of LH was calculated as 60 nM with the determination co-efficient (R2 ) value, 0.9229 [y = 1.296x - 2.8435] on a linear range from 30 nM until 1 μM. Further, biofouling effect on sensing electrode surface was analysed with complementary aptamer sequence, control proteins (Albumin, and globulin). The above GO-aptamer modified interdigitated electrode sensor helps to quantify LH level and diagnose gynaecological endocrinology related complications. This article is protected by copyright. All rights reserved.
  20. Fulltext The Effect of Sr-CoFe2O4 Nanoparticles with Different Particles Sized as Additives in CIP-Based Magnetorheological Fluid
    Nugroho KC, Ubaidillah U, Arilasita R, Margono M, Priyambodo BH, Purnama B, et al.
    Materials (Basel), 2021 Jul 01;14(13).
    PMID: 34279258 DOI: 10.3390/ma14133684
    This study investigated the effect of adding strontium (Sr)-doped cobalt ferrite (CoFe2O4) nanoparticles in carbonyl iron particle (CIP)-based magnetorheological fluids (MRFs). Sr-CoFe2O4 nanoparticles were fabricated at different particle sizes using co-precipitation at calcination temperatures of 300 and 400 °C. Field emission scanning electron microscopy (FESEM) was used to evaluate the morphology of the Sr-CoFe2O4 nanoparticles, which were found to be spherical. The average grain sizes were 71-91 nm and 118-157 nm for nanoparticles that had been calcinated at 300 and 400 °C, respectively. As such, higher calcination temperatures were found to produce larger-sized Sr-CoFe2O4 nanoparticles. To investigate the rheological effects that Sr-CoFe2O4 nanoparticles have on CIP-based MRF, three MRF samples were prepared: (1) CIP-based MRF without nanoparticle additives (CIP-based MRF), (2) CIP-based MRF with Sr-CoFe2O4 nanoparticles calcinated at 300 °C (MRF CIP+Sr-CoFe2O4-T300), and (3) CIP-based MRF with Sr-CoFe2O4 nanoparticles calcinated at 400 °C (MRF CIP+Sr-CoFe2O4-T400). The rheological properties of these MRF samples were then observed at room temperature using a rheometer with a parallel plate at a gap of 1 mm. Dispersion stability tests were also performed to determine the sedimentation ratio of the three CIP-based MRF samples.
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