Displaying publications 1 - 20 of 71 in total

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  1. Zeldin S, Krauss SE, Kim T, Collura J, Abdullah H
    J Youth Adolesc, 2016 08;45(8):1638-51.
    PMID: 26092232 DOI: 10.1007/s10964-015-0320-2
    After-school programs are prevalent across the world, but there is a paucity of research that examines quality within the "black box" of programs at the point of service. Grounded in current theory, this research examined hypothesized pathways between the experience of youth-adult partnership (youth voice in decision-making; supportive adult relationships), the mediators of program safety and engagement, and the developmental outcomes of youth empowerment (leadership competence, policy control) and community connectedness (community connections, school attachment). Surveys were administered to 207 ethnically diverse (47.3 % female; 63.3 % Malay) youth, age 15-16, attending after-school co-curricular programs in Kuala Lumpur, Malaysia. Results showed that youth voice in program decision-making predicted both indicators of youth empowerment. Neither youth voice nor supportive adult relationships was directly associated with community connectedness, however. Program engagement mediated the associations between youth-adult partnership and empowerment. In contrast, program safety mediated the associations between youth-adult partnership and community connectedness. The findings indicate that the two core components of youth-adult partnership-youth voice and supportive adult relationships-may operate through different, yet complementary, pathways of program quality to predict developmental outcomes. Implications for future research are highlighted. For reasons of youth development and youth rights, the immediate challenge is to create opportunities for youth to speak on issues of program concern and to elevate those adults who are able and willing to help youth exercise their voice.
  2. Zaremohzzabieh Z, Abdullah H, Ahrari S, Abdullah R, Md Nor SM
    Digit Health, 2024;10:20552076241226962.
    PMID: 38298527 DOI: 10.1177/20552076241226962
    In light of the rapidly evolving digital landscape, there is an increasing need to explore digital hoarding behavior. This need is driven by concerns regarding its intricate psychological foundations and its impact on individuals within our technology-centric society. This research investigates the influence of various factors, including the fear of missing out, emotional attachment, information overload, and decision fatigue, on digital hoarding behaviors among university students in Iran. Additionally, the study examines the moderating role of maladaptive perfectionism in these relationships. The study involved 275 university students (mean age = 21.62 years; standard deviation = 2.28 years; 65.6% female) selected from four universities in Iran. The data were analyzed using partial least squares structural equation modeling (PLS-SEM). The results revealed that the fear of missing out, emotional attachment, information overload, and decision fatigue significantly predict university students' digital hoarding behavior. Moreover, the findings highlighted the moderating effect of maladaptive perfectionism on the association between emotional attachment and digital hoarding behavior. This suggests that individuals with higher levels of maladaptive perfectionism exhibit amplified digital hoarding tendencies when emotionally attached to their digital data. This study provides a deeper understanding of the relationship between psychological factors and digital hoarding tendencies. These findings have practical implications for educational institutions and mental health professionals, as they can help in developing targeted strategies and interventions to manage digital hoarding behavior in university freshmen and promote healthier digital habits.
  3. Zahari Sham SY, Hanif E, Thambiah SC, Samsudin IN, Mohd Noor S, Osman M, et al.
    Malays J Pathol, 2021 04;43(1):33-40.
    PMID: 33903303
    INTRODUCTION: Cardiovascular disease (CVD) remains the leading cause of death in Malaysia. Identification of asymptomatic at-risk individuals is often achieved by means of a risk prediction algorithm. Traditional CVD risk factors and their associated algorithms are, however, limited by residual CVD risk. High sensitivity C-reactive protein (hsCRP) has emerged as a novel CVD risk factor. This study aimed to evaluate hsCRP as an adjunct CVD risk marker among the adult Malaysian population by determining its correlation with the Framingham Risk Score (FRS). Comparison analyses were done according to sociodemographic, clinical and laboratory factors and between subjects with and without Metabolic Syndrome (MetS).

    METHOD: This cross-sectional study involved eighty-three (n=83) adults attending a health screening program at Universiti Putra Malaysia (UPM). Demographic data, anthropometric measurements and blood samples for fasting blood glucose (FBG), fasting lipid profile (FSL), glycated haemoglobin (HbA1c) and hsCRP were taken. Respondents were grouped according to FRS and the Joint Interim Statement into 10-year CVD risk categories (low, intermediate and high) and MetS, respectively.

    RESULTS: hsCRP was significantly increased in patients with high body mass index (BMI) (p=0.001), at-risk waist circumference (WC) (p=0.001) and MetS (p=0.009). Spearman's correlation coefficient showed a significant positive correlation between hsCRP level and total FRS score (r=0.26, p<0.05) and HDL-C score (r=0.22, p<0.05).

    CONCLUSION: The significant difference of hsCRP levels across obesity levels and MetS with its modest correlation with FRS scores supported the adjunctive role of hsCRP in CVD risk prediction, most likely capturing the inflammatory pathological aspect and thus partly accounting for the residual CVD risk.

  4. Yusof WNSW, Abdullah H
    Trop Life Sci Res, 2020 Apr;31(1):69-84.
    PMID: 32963712 DOI: 10.21315/tlsr2020.31.1.5
    Conventional and modern cancer treatment were reported to manifest adverse effects to the patients. More researches were conducted to search for selective cytotoxic agent of plant natural product on cancer cells. The presences of wide range phytochemicals in Quercus infectoria (QI) extract have been implicated with the cytotoxic effect against various types of cancer cell which remain undiscovered. This present study aimed to evaluate cytotoxic effect of QI extracts on selected human cancer cells and then, the most potent extract was further analysed for general phytochemical constituents. QI galls were extracted successively with n-hexane, ethyl acetate and methanol yielded three main extracts; n-hexane (QIH), ethyl acetate (QIEA) and methanol (QIM), respectively. The most potent extract was qualitatively analysed for the present of tannin, alkaloids, glycosides, saponins, terpenoids, flavonoids and phenolic compounds. Next, the extracts were tested to determine the cytotoxic activity against cervical cancer cells (HeLa), breast cancer cells (MDA-MB-231) and liver cancer cells (Hep G2) using MTT assay. Cytotoxic activity of QI extracts against normal fibroblast (L929) cell line was also evaluated to determine the cytoselective property. Meanwhile, DMSO-treated cells served as negative control while cisplatin-treated cells served as positive control. The most potent extract then chosen to be further investigated for DNA fragmentation as hallmark of apoptosis using Hoechst staining. Qualitative phytochemical analysis revealed the presence of tannin, alkaloids, glycosides, saponins, terpenoids, flavonoids and phenolic compounds. QIEA extract exhibited the most potent cytotoxic activity against HeLa cells with (IC50 value = 6.33 ± 0.33 μg/mL) and showed cytoselective property against L929 cells. DNA fragmentation revealed QIEA induced apoptosis in the treated cells. The richness of phytochemical constituents in QIEA extract might contribute to the potency of cytotoxic activity towards HeLa cells.
  5. Yunus N, Abdullah H, Hanapiah F
    J Prosthet Dent, 2001 Jun;85(6):540-3.
    PMID: 11404753
    This article describes the occlusal rehabilitation of a partially edentulous patient who did not want a removable partial denture. Implants and extensive fixed restorations were used to restore posterior support and treat severely worn dentition, respectively. The treatment offered the patient a functional and esthetic result.
  6. Yung LC, Fei CC, Mandeep J, Binti Abdullah H, Wee LK
    PLoS One, 2014;9(5):e97484.
    PMID: 24830317 DOI: 10.1371/journal.pone.0097484
    The success of printing technology in the electronics industry primarily depends on the availability of metal printing ink. Various types of commercially available metal ink are widely used in different industries such as the solar cell, radio frequency identification (RFID) and light emitting diode (LED) industries, with limited usage in semiconductor packaging. The use of printed ink in semiconductor IC packaging is limited by several factors such as poor electrical performance and mechanical strength. Poor adhesion of the printed metal track to the epoxy molding compound is another critical factor that has caused a decline in interest in the application of printing technology to the semiconductor industry. In this study, two different groups of adhesion promoters, based on metal and polymer groups, were used to promote adhesion between the printed ink and the epoxy molding substrate. The experimental data show that silver ink with a metal oxide adhesion promoter adheres better than silver ink with a polymer adhesion promoter. This result can be explained by the hydroxyl bonding between the metal oxide promoter and the silane grouping agent on the epoxy substrate, which contributes a greater adhesion strength compared to the polymer adhesion promoter. Hypotheses of the physical and chemical functions of both adhesion promoters are described in detail.
  7. Yaacob NS, Ahmad MF, Kawasaki N, Maniyam MN, Abdullah H, Hashim EF, et al.
    Molecules, 2021 Jan 27;26(3).
    PMID: 33513787 DOI: 10.3390/molecules26030653
    Soil extracts are useful nutrients to enhance the growth of microalgae. Therefore, the present study attempts for the use of virgin soils from Peninsular Malaysia as growth enhancer. Soils collected from Raja Musa Forest Reserve (RMFR) and Ayer Hitam Forest Reserve (AHFR) were treated using different extraction methods. The total dissolved nitrogen (TDN), total dissolved phosphorus (TDP), and dissolved organic carbon (DOC) concentrations in the autoclave methods were relatively higher than natural extraction with up to 132.0 mg N/L, 10.7 mg P/L, and 2629 mg C/L, respectively for RMFR. The results of TDN, TDP, and DOC suggested that the best extraction methods are autoclaved at 121 °C twice with increasing 87%, 84%, and 95%, respectively. Chlorella vulgaris TRG 4C dominated the growth at 121 °C twice extraction method in the RMRF and AHRF samples, with increasing 54.3% and 14%, respectively. The specific growth rate (µ) of both microalgae were relatively higher, 0.23 d-1 in the Ayer Hitam Soil. This extract served well as a microalgal growth promoter, reducing the cost and the needs for synthetic medium. Mass production of microalgae as aquatic feed will be attempted eventually. The high recovery rate of nutrients has a huge potential to serve as a growth promoter for microalgae.
  8. Wan Mohd Zamri WMI, Sjahrir F, Yaacob NS, Dzulkafli NF, Ahmad MF, Abdullah H, et al.
    Molecules, 2021 Apr 23;26(9).
    PMID: 33922872 DOI: 10.3390/molecules26092480
    The assessment of water-extractable organic matter using an autoclave can provide useful information on physical, chemical, and biological changes within the soil. The present study used virgin forest soils from Chini Forest Reserve, Langkawi Island, and Kenyir Forest Reserve (Malaysia), extracted using different extraction methods. The dissolved organic carbon (DOC), total dissolved nitrogen (TDN), total dissolved phosphorus (TDP), and ammonium-nitrate content were higher in the autoclave treatments, up to 3.0, 1.3, 1.2, and 1.4 times more than by natural extraction (extracted for 24 h at room temperature). Overall, the highest extractable DOC, TDN, TDP, ammonium and nitrate could be seen under autoclaved conditions 121 °C 2×, up to 146.74 mg C/L, 8.97 mg N/L, 0.23 mg P/L, 5.43 mg N mg/L and 3.47 N mg/L, respectively. The soil extracts became slightly acidic with a higher temperature and longer duration. Similar trends were observed in the humic and nonhumic substances, where different types of soil extract treatments influenced the concentrations of the fractions. Different soil extraction methods can provide further details, thus widening the application of soil extracts, especially in microbes.
  9. Sundaraj Y, Abdullah H, Nezhad NG, Rodrigues KF, Sabri S, Baharum SN
    Curr Issues Mol Biol, 2023 Nov 10;45(11):8989-9002.
    PMID: 37998741 DOI: 10.3390/cimb45110564
    This study describes the cloning, expression and functional characterization of α-humulene synthase, responsible for the formation of the key aromatic compound α-humulene in agarwood originating from Aquilaria malaccensis. The partial sesquiterpene synthase gene from the transcriptome data of A. malaccensis was utilized for full-length gene isolation via a 3' RACE PCR. The complete gene, denoted as AmDG2, has an open reading frame (ORF) of 1671 bp and encodes for a polypeptide of 556 amino acids. In silico analysis of the protein highlighted several conserved motifs typically found in terpene synthases such as Asp-rich substrate binding (DDxxD), metal-binding residues (NSE/DTE), and cytoplasmic ER retention (RxR) motifs at their respective sites. The AmDG2 was successfully expressed in the E. coli:pET-28a(+) expression vector whereby an expected band of about 64 kDa in size was detected in the SDS-PAGE gel. In vitro enzyme assay using substrate farnesyl pyrophosphate (FPP) revealed that AmDG2 gave rise to two sesquiterpenes: α-humulene (major) and β-caryophyllene (minor), affirming its identity as α-humulene synthase. On the other hand, protein modeling performed using AlphaFold2 suggested that AmDG2 consists entirely of α-helices with short connecting loops and turns. Meanwhile, molecular docking via AutoDock Vina (Version 1.5.7) predicted that Asp307 and Asp311 act as catalytic residues in the α-humulene synthase. To our knowledge, this is the first comprehensive report on the cloning, expression and functional characterization of α-humulene synthase from agarwood originating from A. malaccensis species. These findings reveal a deeper understanding of the structure and functional properties of the α-humulene synthase and could be utilized for metabolic engineering work in the future.
  10. Sheikh A, Campbell H, Balharry D, Baqui AH, Bogaert D, Cresswell K, et al.
    J Glob Health, 2018 Dec;8(2):020101.
    PMID: 30603074 DOI: 10.7189/jogh.08.020101
  11. Sandelin K, Apffelstaedt JP, Abdullah H, Murray EM, Ajuluchuku EU
    Scand J Surg, 2002;91(3):222-6.
    PMID: 12449462
    Breast Surgery International (BSI) was formed in 1999 as an integrated society within the International Surgical Society ISS/SIC. One goal is to promote breast surgery world wide and focus on the situation in the developing countries. An edited summary of a symposium on locally advanced breast cancer (LABC) and the current situation in two African countries and in Malaysia is reported. Diagnosis, management and treatment options differ from recommendations that prevail due to lack of resources, lack of access to facilities and cultural and socioeconomic barriers. Younger age at onset, more men are affected and locally advanced breast cancer dominates the clinical panorama. A rational treatment plan for LABC should have chemotherapy, surgery, radiotherapy and hormonal therapy as armaments. A unique opportunity exists for international interchange within a professional organization such as BSI, for providing training opportunities, for clinical and experimental studies of the world' s most common female malignancy.
  12. Samuel O, Othman MHD, Kamaludin R, Sinsamphanh O, Abdullah H, Puteh MH, et al.
    J Environ Manage, 2022 Feb 03;308:114556.
    PMID: 35124308 DOI: 10.1016/j.jenvman.2022.114556
    Oilfield produced water (OPW) is one of the most important by-products, resulting from oil and gas exploration. The water contains a complex mixture of organic and inorganic compounds such as grease, dissolved salt, heavy metals as well as dissolved and dispersed oils, which can be toxic to the environment and public health. This article critically reviews the complex properties of OPW and various technologies for its treatment. They include the physico-chemical treatment process, biological treatment process, and physical treatment process. Their technological strengths and bottlenecks as well as strategies to mitigate their bottlenecks are elaborated. A particular focus is placed on membrane technologies. Finally, further research direction, challenges, and perspectives of treatment technologies for OPW are discussed. It is conclusively evident from 262 published studies (1965-2021) that no single treatment method is highly effective for OPW treatment as a stand-alone process however, conventional membrane-based technologies are frequently used for the treatment of OPW with the ultrafiltration (UF) process being the most used for oil rejection form OPW and oily waste water. After membrane treatment, treated effluents of the OPW could be reused for irrigation, habitant and wildlife watering, microalgae production, and livestock watering. Overall, this implies that target pollutants in the OPW samples could be removed efficiently for subsequent use, despite its complex properties. In general, it is however important to note that feed quality, desired quality of effluent, cost-effectiveness, simplicity of process are key determinants in choosing the most suitable treatment process for OPW treatment.
  13. Samer MS, Faraz Q, Al-Dubai SAR, Vohra F, Abdullah H, Taiyeb-Ali TB, et al.
    Med Princ Pract, 2017;26(5):470-479.
    PMID: 28965115 DOI: 10.1159/000481864
    OBJECTIVES: The aim of this study was to determine the clinical outcomes and predictors of satisfaction in patients with lithium disilicate (LD) ceramic crowns.

    SUBJECTS AND METHODS: Clinical outcomes were assessed in 47 patients with 88 LD crowns using modified United States Public Health Service (USPHS) evaluation criteria and survival rates. The questionnaire for predictors included 3 aspects: (a) sociodemographic characteristics, (b) oral health habits (tooth brushing frequency, flossing frequency, and dental visits), and (c) satisfaction of the restorations (aesthetics, function, fit, cleansability, and chewing ability of the crowns, and overall satisfaction). Frequency distributions were computed using univariate and multivariate analysis. The Student t test and analysis of variance (ANOVA) were used to compare means across variables. Correlation analysis was done to assess the association between continuous variables.

    RESULTS: The age of crowns was 34.7 ± 9.7 months. The survival rate was 96.6% at 35.9 ± 9.2 months. There was a significant association between successful crown function and oral hygiene measures: tooth brushing (p˂ 0.001), dental visits (p = 0.006), and flossing (p = 0.009). A strong negative correlation was observed between aesthetic satisfaction (r = -0.717, p˂ 0.001) and chewing ability (r = -0.639, p˂ 0.001) with crown age. The linear regression model was significant for all predictors (p < 0.05) except overall satisfaction (p > 0.05).

    CONCLUSION: The LD crowns had long survival rates of 96.6% up to 35.9 ± 9.2 months and provided satisfactory clinical performance (low risk of failure). Oral hygiene habits such as brushing, flossing, and regular dental visits influenced patient satisfaction with LD crowns.

  14. Saleh Samer M, Ali TT, Abdullah H
    Oral Health Prev Dent, 2018 7 22;16(3):249-257.
    PMID: 30027164 DOI: 10.3290/j.ohpd.a40758
    PURPOSE: To investigate the clinical performance and clinical survival rate of lithium disilicate-based core ceramic (IPS e.max Press) utilised in single crowns and to the accompanying periodontal health status.

    MATERIALS AND METHODS: A total of 47 patients with 88 IPS e.max Press single crowns were examined at the Faculty of Dentistry, University of Malaya, using modified United States Public Health Service evaluation criteria (USPHS). These 88 crowned teeth included 19 vital and 69 nonvital teeth that were restored with different post and core materials. The periodontal status was compared using the plaque index (PI), gingival recession (GR), modified papillary bleeding index (MPBI) and probing pocket depth (PPD) between the crowned teeth and contralateral control (sound) teeth.

    RESULTS: About 96.6% of the crowns exhibited satisfactory clinical performance. The mean survival rate at three years was 97.7%, and 100% at two years with a low incidence of fractures. There were no staitistically significant differences in the mean gingival recession (p = 0.182) and mean plaque scores (p = 0.102) between crowned and control teeth. The crowned teeth had higher mean MPBI (p = 0.000) and PPD (p = 0.051) compared to the contralateral sound teeth. Periodontal response in relation to subgingival crown margins, was statistically significantly lower regarding pocket depths (p = 0.01) and bleeding on probing (p = 0.00).

    CONCLUSION: IPS e.max Press crowns exhibited satisfactory clinical performance with high survival rate. No dentinal sensitivity was recorded. Plaque retention and gingival recession were similar to contralateral control teeth. Poor periodontal health was related to the subgingival crown margins.

  15. Safdar Bajwa R, Abdullah H, Zaremohzzabieh Z, Wan Jaafar WM, Abu Samah A
    Front Psychol, 2022;13:1072551.
    PMID: 36687837 DOI: 10.3389/fpsyg.2022.1072551
    INTRODUCTION: This article examines mediators and moderators that may explain the link between smartphone addiction and phubbing behavior using a sample of 794 university students.

    METHODS: A mediation model was tested to test the hypothesis that social comparison orientation and fear of missing out would mediate the link between smartphone addiction and phubbing behavior. Additionally, a moderated mediation model was leveraged to examine loneliness as a moderator within the hypothesized model. The data collected were analyzed using SPSS.

    RESULTS AND DISCUSSION: The findings show a significant positive relationship between smartphone addiction and phubbing behavior. The findings confirm the hypothesized associations and reveal that smartphone addiction is positively linked to phubbing behavior. The link, on the other hand, is partially and sequentially mediated by the fear of missing out and social comparison orientation. As a result, both mediators might be regarded as proximal variables of phubbing behavior. Moreover, the associations between both smart addiction and phubbing behaviors as well as social comparison orientation and phubbing behaviors are moderated by loneliness. These two effects were stronger for university students with high loneliness than for those with low loneliness. This study addresses a major gap in the clinical psychology literature through the attempt to explore the relationship between smartphone addiction and increased phubbing behavior among university students.

  16. Rasool AH, Ghazali DM, Abdullah H, Halim AS, Wong AR
    Microvasc Res, 2009 Sep;78(2):230-4.
    PMID: 19481100 DOI: 10.1016/j.mvr.2009.05.005
    Post occlusive skin reactive hyperemia (PORH) is a tool used to assess microcirculation. Endothelial nitric oxide synthase (eNOS) mediates nitric oxide (NO) production; polymorphism of the eNOS gene may affect response to the PORH process. This study aims to determine whether eNOS G894T gene polymorphism affects response to skin PORH. 230 normotensive male and females between 18 and 40 years participated in this cross-sectional study. 170 subjects were of the homozygous GG genotype, whereas 60 were of the GT genotype. Skin PORH was performed by occlusion of the upper arm at 200 mm Hg for 3 min. Skin perfusion and temperature were monitored before, during and after occlusion release using the laser Doppler fluximetry. There were no significant differences between genotypes in their baseline blood pressure, serum cholesterol, BMI and age. Maximum change in perfusion after occlusion release (PORHmax) for the GG and GT genotypes were not significantly different at 50.15+/-1.29 vs. 47.92+/-2.17 AU; ANCOVA, p=0.351. Peak perfusion (PORHpeak) were also not significantly different between the two genotypes (61.23+/-1.36 vs. 57.72+/-2.32 AU; p=0.169). Minimum baseline perfusion were however higher in the GG compared to the GT genotype (10.83+/-0.29 vs. 9.61+/-0.50, p=0.029). We conclude that microvascular reactivity, assessed by change in perfusion after temporary ischemia was not significantly different between the GG and GT genotypes of the eNOS G894T gene. eNOS 894T allele carriers however, have lower baseline perfusion compared to the homozygous G894 allele carrier.
  17. Noushad M, Kannan TP, Husein A, Abdullah H, Ismail AR
    Toxicol In Vitro, 2009 Sep;23(6):1145-50.
    PMID: 19505568 DOI: 10.1016/j.tiv.2009.05.025
    The aim of this study was to determine the genotoxicity of a locally produced dental porcelain (Universiti Sains Malaysia, Malaysia) using the Ames and Comet assays. In the Ames assay, four genotypic variants of the Salmonella strains (TA98, TA100, TA1537 and TA1535) carrying mutations in several genes were used. The dental porcelain was incubated with these four strains in five different doses both in the presence and absence of metabolic activation (S9) and the result was assessed based on the number of revertant colonies. Concurrently, appropriate positive controls were used so as to validate the test. The average number of revertant colonies per plate treated with locally produced dental porcelain was less than double as compared to that of negative control. In the Comet assay, L929 (CCL-1 ATCC, USA) mouse fibroblast cells were treated with the dental porcelain in three different concentrations along with concurrent negative and positive controls. The tail moment which was used as a measurement of DNA damage was almost equal to that of the negative control, suggesting that the locally produced dental porcelain did not induce any DNA damage. The results indicated that the locally produced dental porcelain is non-genotoxic under the present test conditions.
  18. Nor Azlin MI, Abdullah HS, Zainul Rashid MR, Jamil MA
    J Obstet Gynaecol, 2006 Aug;26(6):546-9.
    PMID: 17000504
    Gemeprost (Cervagem) has been used widely compared with Misoprostol (Cytotec) alone in second trimester pregnancy termination. This prospective randomised trial was to evaluate the efficacy of intravaginal Misoprostol (alone) and Gemeprost in second trimester termination of pregnancy. A total of 54 women with 27 on each arm were involved. A total of 25 patients (92.6%) in the Misoprostol group and 22 patients (81.5%) in the Gemeprost group delivered within 48 h. The Misoprostol group delivered earlier, although average number of tablets required were similar. The side-effects were not significant between the two groups in fact, but there was more pyrexia in the Gemeprost group (p = 0.004). Misoprostol in second trimester termination of pregnancy is clinically as effective and less costly than the standard regimen of Gemeprost.
  19. Nadzirah S, Mohamad Zin N, Khalid A, Abu Bakar NF, Kamarudin SS, Zulfakar SS, et al.
    Crit Rev Anal Chem, 2023 Jun 26.
    PMID: 37358486 DOI: 10.1080/10408347.2023.2224433
    Since diagnostic laboratories handle large COVID-19 samples, researchers have established laboratory-based assays and developed biosensor prototypes. Both share the same purpose; to ascertain the occurrence of air and surface contaminations by the SARS-CoV-2 virus. However, the biosensors further utilize internet-of-things (IoT) technology to monitor COVID-19 virus contamination, specifically in the diagnostic laboratory setting. The IoT-capable biosensors have great potential to monitor for possible virus contamination. Numerous studies have been done on COVID-19 virus air and surface contamination in the hospital setting. Through reviews, there are abundant reports on the viral transmission of SARS-CoV-2 through droplet infections, person-to-person close contact and fecal-oral transmission. However, studies on environmental conditions need to be better reported. Therefore, this review covers the detection of SARS-CoV-2 in airborne and wastewater samples using biosensors with comprehensive studies in methods and techniques of sampling and sensing (2020 until 2023). Furthermore, the review exposes sensing cases in public health settings. Then, the integration of data management together with biosensors is well explained. Last, the review ended with challenges to having a practical COVID-19 biosensor applied for environmental surveillance samples.
  20. Mohd Pu'ad NAS, Koshy P, Abdullah HZ, Idris MI, Lee TC
    Heliyon, 2019 May;5(5):e01588.
    PMID: 31080905 DOI: 10.1016/j.heliyon.2019.e01588
    Waste materials from natural sources are important resources for extraction and recovery of valuable compounds. Transformation of these waste materials into valuable materials requires specific techniques and approaches. Hydroxyapatite (HAp) is a biomaterial that can be extracted from natural wastes. HAp has been widely used in biomedical applications owing to its excellent bioactivity, high biocompatibility, and excellent osteoconduction characteristics. Thus, HAp is gaining prominence for applications as orthopaedic implants and dental materials. This review summarizes some of the recent methods for extraction of HAp from natural sources including mammalian, aquatic or marine sources, shell sources, plants and algae, and from mineral sources. The extraction methods used to obtain hydroxyapatite are also described. The effect of extraction process and natural waste source on the critical properties of the HAp such as Ca/P ratio, crystallinity and phase assemblage, particle sizes, and morphology are discussed herein.
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