Displaying publications 21 - 40 of 51 in total

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  1. Yahya R, Bavanandan S, Yap YC, Jazilah W, Shaariah W, Wong HS, et al.
    Med J Malaysia, 2008 Sep;63 Suppl C:18-9.
    PMID: 19230242
  2. Rizwan M, Yahya R, Hassan A, Yar M, Azzahari AD, Selvanathan V, et al.
    Polymers (Basel), 2017 06 14;9(6).
    PMID: 30970902 DOI: 10.3390/polym9060225
    The authors wish to make a change to their published paper [1]. [...].
  3. Wong XZ, Gan CC, Mohamed R, Yahya R, Ganapathy S, Tan SS, et al.
    BMC Nephrol, 2020 11 13;21(1):480.
    PMID: 33187498 DOI: 10.1186/s12882-020-02154-4
    BACKGROUND: Hepatitis C virus (HCV) infects more than 71 million people worldwide and chronic HCV infection increases the risk of liver cirrhosis and failure. Haemodialysis (HD) is one of the renal replacement therapies with risk of HCV transmission. Anti-HCV antibodies are the serological screening test for HCV infection that does not detect active phase of infection. Majority HCV infected HD patients in Malaysia do not have further HCV RNA performed due to high cost and thus HCV treatment is less frequently offered. HCV Core Antigen (HCV Ag) can potentially be used to diagnose active HCV infection in HD population in comparison to HCV RNA, at lower cost.

    METHODS: We conducted a cross-sectional study to assess the correlation between HCV Ag and HCV RNA and to identify the prevalence of active HCV infection among HCV seropositive HD patients from dialysis centres across West Malaysia from July 2019 to May 2020. Pre-dialysis blood was taken and tested for both HCV Ag and HCV RNA tests. HCV Ag was tested with Abbott ARCHITECT HCV Ag test.

    RESULTS: We recruited 112 seropositive HD patients from 17 centres with mean age of 54.04 ± 11.62 years, HD vintage of 14.1 ± 9.7 years, and male constitute 59.8% (67) of the study population. HCV Ag correlates well with HCV RNA (Spearman test coefficient 0.833, p  3000 IU/mL, HCV Ag had a higher sensitivity of 95.1% and greater correlation (Spearman test coefficient 0.897, p 

  4. Naeem R, Ali Ehsan M, Yahya R, Sohail M, Khaledi H, Mazhar M
    Dalton Trans, 2016 Oct 14;45(38):14928-39.
    PMID: 27549401 DOI: 10.1039/c6dt02656g
    Pristine Mn2O3 and Ag-Mn2O3 composite thin films have been developed on fluorine doped tin oxide (FTO) coated glass substrates at 450 °C by aerosol assisted chemical vapor deposition (AACVD) using a methanol solution of a 1 : 2 mixture of acetatoargentate(i), Ag(CH3COO), and a newly synthesized manganese complex, [Mn(dmae)2(TFA)4] (1) (dmae = N,N-dimethylaminoethanolate, TFA = trifluoroacetate). The phase purity and stoichiometric composition of the films were investigated by X-ray diffraction (XRD) and Raman spectroscopy techniques. Energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) analyses revealed a Ag to Mn ratio of 1 : 2 and further confirmed the uniform dispersion of Ag nanoparticles into the Mn2O3 structure. Optical studies showed a direct band gap of 2.0 eV for the pristine Mn2O3 film that was lowered to 1.8 eV for Ag-Mn2O3 due to the plasmonic interaction of Ag with Mn2O3. The Ag-Mn2O3 composite film displayed enhanced photocatalytic activity in photoelectrochemical (PEC) water splitting and yielded a photocurrent of 3 mA cm(-2) at 0.7 V versus Ag/AgCl which was 1.6 times higher than a pristine Mn2O3 film alone, under AM 1.5 G illumination (100 mW cm(-2)). The high PEC efficiency is mainly due to the plasmonic effect of Ag nanoparticles, which enhances the visible light absorption, efficient electron-hole separation and high carrier mobility of the Ag-Mn2O3 photoelectrode. The charge carrier density of Ag-Mn2O3 is two times higher than the pristine Mn2O3 as calculated by the Mott-Schottky plot. Based on the PEC studies a mechanism is proposed to elucidate the high activity of Ag-Mn2O3 in PEC water splitting.
  5. Al-Mokaram AMAAA, Yahya R, Abdi MM, Mahmud HNME
    Nanomaterials (Basel), 2017 May 31;7(6).
    PMID: 28561760 DOI: 10.3390/nano7060129
    The performance of a modified electrode of nanocomposite films consisting of polypyrrole-chitosan-titanium dioxide (Ppy-CS-TiO₂) has been explored for the developing a non-enzymatic glucose biosensors. The synergy effect of TiO₂ nanoparticles (NPs) and conducting polymer on the current responses of the electrode resulted in greater sensitivity. The incorporation of TiO₂ NPs in the nanocomposite films was confirmed by X-ray photoelectron spectroscopy (XPS) spectra. FE-SEM and HR-TEM provided more evidence for the presence of TiO₂ in the Ppy-CS structure. Glucose biosensing properties were determined by amperommetry and cyclic voltammetry (CV). The interfacial properties of nanocomposite electrodes were studied by electrochemical impedance spectroscopy (EIS). The developed biosensors showed good sensitivity over a linear range of 1-14 mM with a detection limit of 614 μM for glucose. The modified electrode with Ppy-CS nanocomposite also exhibited good selectivity and long-term stability with no interference effect. The Ppy-CS-TiO₂ nanocomposites films presented high electron transfer kinetics. This work shows the role of nanomaterials in electrochemical biosensors and describes the process of their homogeneous distribution in composite films by a one-step electrochemical process, where all components are taken in a single solution in the electrochemical cell.
  6. Rizwan M, Yahya R, Hassan A, Yar M, Abd Halim AA, Rageh Al-Maleki A, et al.
    J Mater Sci Mater Med, 2019 Jun 11;30(6):72.
    PMID: 31187295 DOI: 10.1007/s10856-019-6273-3
    The success of wound healing depends upon the proper growth of vascular system in time in the damaged tissues. Poor blood supply to wounded tissues or tissue engineered grafts leads to the failure of wound healing or rejection of grafts. In present paper, we report the synthesis of novel organosoluble and pro-angiogenic chitosan derivative (CSD) by the reaction of chitosan with 1,3-dimethylbarbituric acid and triethylorthoformate (TEOF). The synthesized material was characterized by FTIR and 13C-NMR to confirm the incorporated functional groups and new covalent connectivities. Biodegradability of the synthesized chitosan derivative was tested in the presence of lysozyme and was found to be comparable with CS. The cytotoxicity and apoptosis effect of new derivative was determined against gastric adenocarcinoma (AGS) cells and was found to be non-toxic. The CSD was found to be soluble in majority of organic solvents. It was blended with polycaprolactone (PCL) to form composite scaffolds. From an ex ovo CAM assay, it was noted that CSD stimulated the angiogenesis.
  7. Lim CK, Lim JH, Ibrahim I, Chan YM, Zakaria NF, Yahya R, et al.
    Diagnostics (Basel), 2021 Sep 23;11(10).
    PMID: 34679443 DOI: 10.3390/diagnostics11101745
    Protein-energy wasting (PEW) is a devastating metabolic derangement that leads to increased morbidity and mortality in hemodialysis (HD) patients. This study aimed to determine the diagnostic test accuracy of bioelectrical impedance analysis derived-phase angle (PhA) in detecting PEW among HD patients. This was a multi-centre, cross-sectional study conducted amongst 152 multi-ethnic HD patients in Klang Valley, Malaysia. PEW was assessed using the International Society of Renal Nutrition and Metabolism criteria as the reference method. PhA was measured using a multi-frequency bioelectrical impedance spectroscopy at 50 kHz. Multiple and logistic regressions were used to determine factors associated with PhA and PEW diagnosis, respectively. A receiver operating characteristics curve analysis was used to establish the gender-specific PhA cut-offs to detect PEW. PEW existed in 21.1% of the HD patients. PhA was found as an independent predictor of PEW (adjOR = 0.308, p = 0.001), with acceptable to excellent discriminative performance (adjAUCmale = 0.809; adjAUCfemale = 0.719). Male patients had higher PhA cut-off compared to female patients (4.26° vs. 3.30°). We concluded that PhA is a valid and pragmatic biomarker to detect PEW in multi-ethnic Malaysian HD patients and a gender-specific cut-off is necessary, attributed to the gender differences in body composition.
  8. Asghar M, Yahya R, Yap AUJ, Azzahari AD, Omar RA
    Caries Res, 2022;56(3):149-160.
    PMID: 35871511 DOI: 10.1159/000525505
    Silver diammine fluoride (SDF) is known as a noninvasive, cost-effective, safe, and simple method of dental caries treatment. However, staining and discoloration seem inseparable with SDF and continue as a cosmetic concern. Research is ongoing to overcome these issues, for example, by using glutathione (G) or potassium iodide among others. Therefore, the study aimed to investigate the effects of incorporating different concentrations of capping agents on SDF chemistry and SDF-mediated tooth staining at different time points. Tannic acid (TA), gallic acid (GA), carboxymethyl chitosan (CM), and G at different concentrations (5, 10, and 15% w/v) were incorporated in 30% SDF. FTIR and UV-Vis spectroscopies of the prepared solutions was performed to evaluate chemical changes. Time-dependent color changes (ΔE) in bovine dentine specimens (6 × 6 × 1 ± 0.25 mm3) were measured spectrophotometrically at application/washup, 1 and 3 h, after 1, 2, 4, 7, and 14 days. Results showed suppression of FTIR peaks at 3,358 cm-1 and 1,215 cm-1 in capping agent-modified SDF indicative of a successful capping effect of the silver ions, which was corroborated by UV-Vis blueshift of ∼∆32 nm. The capping effect on SDF increased proportionally with the concentrations of TA, GA, CM, and G used. A more pronounced tooth staining reduction however was shown more in TA- and G- rather than in GA- and CM-modified SDF. At day 14, SDF showed the highest mean ΔE(50.14 ± 2.14), while 15% TA showed the lowest ΔE(30.14 ± 0.81). In conclusion, capping agent incorporation significantly reduced SDF-mediated tooth staining. This reduction in staining is more dependent on the respective capping agent functional groups than concentrations per se. The potential of capping agents to minimize tooth staining of SDF was TA>G>CM>GA.
  9. Boey CY, Yee SY, Amir Hassan SZ, Yahya R, Hashim H
    Transplant Proc, 2022 Jan 24.
    PMID: 35086676 DOI: 10.1016/j.transproceed.2021.12.016
    INTRODUCTION: Accurate assessment of renal graft function in the early post-transplant period is crucial, as it influences clinical management and graft prognostication. However, there are limitations in current available modalities. MAG3 scintigraphy could contribute vital information on graft function.

    OBJECTIVES: This study aimed to determine the predictive value of parameters derived from MAG3 performed within 72 hours post transplant in detecting graft function. Delayed graft function (DGF), which is defined as dialysis requirement within the first week post transplant, is chosen as a surrogate measure of graft function.

    METHODOLOGY: All renal transplant recipients who underwent MAG3 within 72 hours post transplant from 2017 to 2019 were enrolled. Three MAG3 parameters, renogram grade, tubular injury severity score, and R20:3, were evaluated.

    RESULTS: A total of 117 patients were enrolled. The overall incidence of DGF was 16.2% with a significantly higher incidence amongst cadaveric graft recipients (53.6%) compared with living graft recipients (4.5%). Renogram grade ≥2, tubular injury severity score ≥4, and R20:3 > 1.31 significantly predicted DGF, P < .05 with high area under the curve for R20:3 of 0.97. Grafts with parameters above the cutoffs also showed significantly worse GFR at 1- and 3-months post-transplant. On multivariate analysis, prolonged cold ischemia time was associated with a higher risk of DGF, odds ratio 1.005 (95% confidence interval 1.003-1.007), P < .05.

    CONCLUSION: Baseline MAG3 accurately depicts early graft function and was also predictive of GFR at 1- and 3- months post-transplant. These baseline MAG3 scans could be particularly useful amongst deceased donor graft recipients owing to the higher risk of poor graft function.

  10. Abouloula CN, Rizwan M, Selvanathan V, Yahya R, Althubeiti K, Alkhammash HI, et al.
    Polymers (Basel), 2021 Oct 26;13(21).
    PMID: 34771242 DOI: 10.3390/polym13213685
    This study explores the possibility of transforming lignocellulose-rich agricultural waste materials into value-added products. Cellulose was extracted from an empty fruit bunch of oil palm and further modified into carboxymethyl cellulose (CMC), a water-soluble cellulose derivative. The CMC was then employed as the polymeric content in fabrication of solid polymer electrolyte (SPE) films incorporated with lithium iodide. To enhance the ionic conductivity of the solid polymer electrolytes, the compositions were optimized with different amounts of glycerol as a plasticizing agent. The chemical and physical effects of plasticizer content on the film composition were studied by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analysis. FTIR and XRD analysis confirmed the interaction plasticizer with the polymer matrix and the amorphous nature of fabricated SPEs. The highest ionic conductivity of 6.26 × 10-2 S/cm was obtained with the addition of 25 wt % of glycerol. By fabricating solid polymer electrolytes from oil palm waste-derived cellulose, the sustainability of the materials can be retained while reducing the dependence on fossil fuel-derived materials in electrochemical devices.
  11. Yusuf SNF, Azzahari AD, Selvanathan V, Yahya R, Careem MA, Arof AK
    Carbohydr Polym, 2017 Feb 10;157:938-944.
    PMID: 27988011 DOI: 10.1016/j.carbpol.2016.10.032
    A binary salt system utilizing lithium iodide (LiI) as the auxiliary component has been introduced to the N-phthaloylchitosan (PhCh) based gel polymer electrolyte consisting of ethylene carbonate (EC), dimethylformamide (DMF), tetrapropylammonium iodide (TPAI), and iodine (I2) in order to improve the performance of dye-sensitized solar cell (DSSC) with efficiency of 6.36%, photocurrent density, JSC of 17.29mAcm-2, open circuit voltage, VOC of 0.59V and fill factor, FF of 0.62. This efficiency value is an improvement from the 5.00% performance obtained by the DSSC consisting of only TPAI single salt system. The presence of the LiI in addition to the TPAI improves the charge injection rates and increases the iodide contribution to the total conductivity and both factors contribute to the increase in efficiency of the DSSC. The interaction behavior between polymer-plasticizer-salt was thoroughly investigated using EIS, FTIR spectroscopy and XRD.
  12. Asghar M, Omar RA, Yahya R, Yap AU, Shaikh MS
    J Esthet Restor Dent, 2023 Mar;35(2):322-332.
    PMID: 36628650 DOI: 10.1111/jerd.13013
    OBJECTIVE: To the effectiveness of different strategies to overcome silver diamine fluoride (SDF)-mediated tooth staining.

    MATERIALS AND METHODS: Four online databases (PubMed, ScienceDirect, Scopus, and Web of Science) were searched using different MeSH terms and Boolean Operators to retrieve the articles (until June 2021), followed by a hand-search of the reference list of the included articles. All full-text, original studies in English that evaluated SDF staining and at least one SDF modification/alternative were included.

    RESULTS: Among the assessed studies, nine studies explored the stain-minimization effect of potassium iodide (KI) post-application following SDF treatment. Among these, eight concluded that KI application after SDF treatment significantly reduced tooth staining, while one showed marginal staining following glass ionomer restoration of the SDF-treated dentine. Additionally, one study applied potassium fluoride (KF) and silver nitrate (AgNO3 ) concurrently to mitigate SDF-mediated staining. One study compared SDF staining with polyethylene glycol (PEG)-coated nanoparticles containing sodium fluoride (NaF), and another used nanosilver fluoride (NSF) for staining comparison with SDF.

    CONCLUSIONS: Within the limitations of this study, the addition of different materials to SDF has proven to be a beneficial strategy for overcoming tooth staining associated with SDF. Future studies are warranted, particularly clinical trials, to validate these findings.

    CLINICAL SIGNIFICANCE: SDF-mediated tooth staining is a serious concern that limits its clinical use. A review of various strategies to overcome this problem will help clinicians enhance its clinical use and patient acceptance.

  13. Farhan N, Rageh Al-Maleki A, Ataei S, Muhamad Sarih N, Yahya R
    Bioorg Chem, 2023 Jun;135:106511.
    PMID: 37027951 DOI: 10.1016/j.bioorg.2023.106511
    Medication products from natural materials are preferred due to their minimal side effects. Extra-virgin olive oil (EVOO) is a highly acclaimed Mediterranean diet and a common source of lipids that lowers morbidity and disease severity. This study synthesised two fatty amides from EVOO: hydroxamic fatty acids (FHA) and fatty hydrazide hydrate (FHH). The Density Functional Theory (DFT) was applied to quantum mechanics computation. Nuclear magnetic resonance (NMR), Fourier transforms infrared (FTIR), and element analysis were used to characterise fatty amides. Likewise, the minimum inhibitory concentration (MIC) and timing kill assay were determined. The results revealed that 82 % for FHA and 80 % for FHH conversion were achieved. The amidation reagent/EVOO ratio (mmol: mmol) was 7:1, using the reaction time of 12 h and hexane as an organic solvent. The results further revealed that fatty amides have high antibacterial activity with low concentration at 0.04 μg/mL during eight h of FHA and 0.3 μg/mL during ten h of FHH. This research inferred that FHA and FHH could provide an alternative and effective therapeutic strategy for bacterial diseases. Current findings could provide the basis for the modernisation/introduction of novel and more effective antibacterial drugs derived from natural products.
  14. Selvanathan V, Yahya R, Ruslan MH, Sopian K, Amin N, Nour M, et al.
    Polymers (Basel), 2020 Feb 27;12(3).
    PMID: 32120814 DOI: 10.3390/polym12030516
    This work is a pioneer attempt to fabricate quasi-solid dye-sensitized solar cell (QSDDSC) based on organosoluble starch derivative. Rheological characterizations of the PhSt-HEC blend based gels exhibited viscoelastic properties favorable for electrolyte fabrication. From amplitude sweep and tack test analyses, it was evident that the inclusion of LiI improved the rigidity and tack property of the gels. On the other hand, the opposite was true for TPAI based gels, which resulted in less rigid and tacky electrolytes. The crystallinity of the gels was found to decline with increasing amount of salt in both systems. The highest photoconversion efficiency of 3.94% was recorded upon addition of 12.5 wt % TPAI and this value is one of the highest DSSC performance recorded for starch based electrolytes. From electrochemical impedance spectroscopy (EIS), it is deduced that the steric hindrance imposed by bulky cations aids in hindering recombination between photoanode and electrolyte.
  15. Thong KM, Jalalonmuhali M, Choo CL, Yee SY, Yahya R, Jeremiah PN, et al.
    Med J Malaysia, 2024 Mar;79(2):234-236.
    PMID: 38553931
    Diabetes mellitus is the main aetiology of end stage kidney disease (ESKD) in Malaysia. However, there may be concerns of over-reporting of diabetes mellitus as the cause of ESKD in the Malaysian Dialysis and Transplant Registry (MDTR). The objective of this audit is to assess the accuracy of data collected in the MDTR. There were 151 centres/source data providers (SDP) with a total of 1977 patients included in this audit. The audit showed that 80.2% of doctors' records matched the MDTR data. The results were comparable with published validation studies in other countries.
  16. Ali ZA, Roslan MA, Yahya R, Wan Sulaiman WY, Puteh R
    IET Nanobiotechnol, 2017 Mar;11(2):152-156.
    PMID: 28476997 DOI: 10.1049/iet-nbt.2015.0123
    In this study, larvicidal activity of silver nanoparticles (AgNPs) synthesised using apple extract against fourth instar larvae of Aedes aegypti was determined. As a result, the AgNPs showed moderate larvicidal effects against Ae. aegypti larvae (LC50 = 15.76 ppm and LC90 = 27.7 ppm). In addition, comparison of larvicidal activity performance of AgNPs at high concentration prepared using two different methods showed that Ae. aegypti larvae was fully eliminated within the duration of 2.5 h. From X-ray diffraction, the AgNP crystallites were found to exhibit face centred cubic structure. The average size of these AgNPs as estimated by particle size distribution was in the range of 50-120 nm. The absorption maxima of the synthesised Ag showed characteristic Ag surface plasmon resonance peak. This green synthesis provides an economic, eco-friendly and clean synthesis route to Ag.
  17. Mansoor MA, Ismail A, Yahya R, Arifin Z, Tiekink ER, Weng NS, et al.
    Inorg Chem, 2013 May 20;52(10):5624-6.
    PMID: 23627942 DOI: 10.1021/ic302772b
    Perovskite-structured lead titanate thin films have been grown on FTO-coated glass substrates from a single-source heterometallic molecular complex, [PbTi(μ2-O2CCF3)4(THF)3(μ3-O)]2 (1), which was isolated in quantitative yield from the reaction of tetraacetatolead(IV), tetrabutoxytitanium(IV), and trifluoroacetic acid from a tetrahydrofuran solution. Complex 1 has been characterized by physicochemical methods such as melting point, microanalysis, FTIR, (1)H and (19)F NMR, thermal analysis, and single-crystal X-ray diffraction (XRD) analysis. Thin films of lead titanate having spherical particles of various sizes have been grown from 1 by aerosol-assisted chemical vapor deposition at 550 °C. The thin films have been characterized by powder XRD, scanning electron microscopy, and energy-dispersive X-ray analysis. An optical band gap of 3.69 eV has been estimated by UV-visible spectrophotometry.
  18. Gan CC, Jalalonmuhali M, Nordin NZ, Abdul Wahab MZ, Yahya R, Ng KP, et al.
    Transplant Proc, 2021 Apr;53(3):856-864.
    PMID: 33487455 DOI: 10.1016/j.transproceed.2020.10.038
    Malaysia has a low deceased-donor donation rate and has not embarked on a paired kidney exchange program; therefore, ABO-incompatible and HLA-incompatible transplantation remain the main contributor to the sustainability of the national kidney transplantation (KT) program. There were 26 cases of ABO-incompatible KTs performed from 2011 to 2018 in 3 major transplant centers, namely, Hospital Kuala Lumpur, University Malaya Medical Centre, and Prince Court Medical Centre. We collected perioperative and follow-up data through June 2019. The desensitization protocol varies and is center specific: the localized Japanese protocol and Swedish protocol with a target anti-A/B isoagglutinin titer of 16 or 32 on the day of transplant. The induction and tacrolimus-based maintenance protocol was nearly identical. The median follow-up time was 62.3 months (interquartile range, 37.0-79.7). Fifteen subjects had the highest predesensitization anti-A/B titer of ≥32 (57.7%). The acute cellular rejection and antibody-mediated rejection incidence were 12.5% (3 cases) and 8.3% (2 cases), respectively. Patient, graft, and death-censored graft survival rates were 96.2%, 92.3%, and 96.0%, respectively, 1 year post-living-donor KT (LDKT) and 96.2%, 87.2%, and 90.7%, respectively, 5 years post-LDKT. Our experience shows that ABO-incompatible LDKT using a suitable desensitization technique could be a safe and feasible choice for LDKT even with varied desensitization regimens for recipients with relatively high baseline isoagglutinin titers.
  19. Wong XZ, Amirah A, Gan CC, Fatiha S, Maznah D, Yahya R, et al.
    Nephrology (Carlton), 2021 May;26(5):463-470.
    PMID: 33580732 DOI: 10.1111/nep.13862
    AIMS: In Malaysia, majority anti-HCV positive haemodialysis patients do not undergo hepatitis C confirmation due to the high cost of HCV RNA. HCV Core Antigen might be a cost-effective diagnostic test to identify HD patients who have active HCV infection eligible for Direct Acting Anti-viral therapy.

    METHODS: A cross-sectional study was conducted to assess the correlation between HCV Ag and HCV RNA and the cost implications of different diagnostic algorithms to diagnose active HCV infection using Anti-HCV, HCV Ag, and HCV RNA. Pre-dialysis blood was tested for both HCV Ag and HCV RNA. HCV Ag was tested with Abbott ARCHITECT HCV Ag test.

    RESULTS: Two-hundred twenty-seven haemodialysis patients were recruited from 20 centres with mean age of 57.68 ± 12.48 years, and male constitutes 56.8% (129) of the study population. HCV Ag correlated well with HCV RNA (Spearman test coefficient 0.943, p 

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