Displaying publications 1 - 20 of 50 in total

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  1. 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.
  2. Sim LH, Gan SN, Chan CH, Yahya R
    Spectrochim Acta A Mol Biomol Spectrosc, 2010 Aug;76(3-4):287-92.
    PMID: 20444642 DOI: 10.1016/j.saa.2009.09.031
    The interaction behaviours between components of polyacrylate (PAc)/poly(ethylene oxide) (PEO) and lithium perchlorate (LiClO(4)) were investigated in detail by Attenuated Total Reflectance (ATR)-Fourier Transformed Infrared (FTIR) spectroscopy. Solution cast films of the PAc/PEO and PAc/PEO/LiClO(4) were examined. No obvious shifting of the characteristic ether and ester group stretching modes of PEO and PAc was observed, indicating incompatibility of the binary PAc/PEO blend. The spectroscopic studies on the PAc/PEO/LiClO(4) blends reveal that Li(+) ions coordinate individually to the polymer components at the ether oxygen of PEO and the C-O of the ester group of PAc. Frequency changes observed on the nu(C-O-C) and omega(CH(2)) of PEO confirm the coordination between PEO and Li(+) ions resulting in crystallinity suppression of PEO. The absence of experimental evidence on the formation of PEO-Li(+)-PAc complexes suggests that LiClO(4) does not enhance the compatibility of PAc/PEO blend.
  3. Vikneswaran R, Syafiq MS, Eltayeb NE, Kamaruddin MN, Ramesh S, Yahya R
    PMID: 26046495 DOI: 10.1016/j.saa.2015.05.087
    Copper ion recognition and DNA interaction of a newly synthesized fluorescent Schiff base (HPyETSC) were investigated using UV-vis and fluorescent spectroscopy. Examination using these two techniques revealed that the detection of copper by HPyETSC is highly sensitive and selective, with a detection limit of 0.39 μm and the mode of interaction between HPyETSC and DNA is electrostatic, with a binding constant of 8.97×10(4) M(-1). Furthermore, gel electrophoresis studies showed that HPyETSC exhibited nuclease activity through oxidative pathway.
  4. Selvanathan V, Azzahari AD, Abd Halim AA, Yahya R
    Carbohydr Polym, 2017 Jul 01;167:210-218.
    PMID: 28433156 DOI: 10.1016/j.carbpol.2017.03.023
    A first-of-its-kind, eco-friendly quasi-solid bioelectrolyte derived from potato starch was prepared. Starch was chemically modified via phthaloylation to synthesize amorphous, hydrophobic starch derivative and the attachment of the phthaloyl group was confirmed via FTIR which showed phthalate ester peak at 1715cm-1; and 1H NMR peaks between 7.30-7.90ppm attributed to the aromatic protons of the phthaloyl group. The resulting starch derivative was then infused with ternary natural deep eutectic solvent (NADES) made from different molar ratios of choline chloride, urea and glycerol. Electrochemical Impedance Spectroscopy (EIS) revealed that the highest ionic conductivity was obtained by the system consisting of NADES with choline chloride:urea:glycerol in molar ratios of 4:6:2, with a magnitude of 2.86mScm-1, hence validating the prospects of the materials to be further experimented as an alternative electrolyte in various electrochemical devices.
  5. Ng YM, Lim YS, Ee LW, Fong VK, Low CL, Yee SY, et al.
    Transplant Proc, 2022 Jan 29.
    PMID: 35105465 DOI: 10.1016/j.transproceed.2022.01.002
    BACKGROUND: The Malaysian Kidney Allocation System implemented in 2020 includes only kidney transplant candidates with estimated posttransplant survival (EPTS) score of ≤20%, in replacement of Malaysian Organs Sharing System, which was based solely on dialysis vintage. We aim to compare the clinical outcomes of deceased-donor kidney transplant recipients (DDKTRs) with EPTS ≤20% to those with EPTS >20%.

    METHODS: All DDKTRs between January 1, 2015, and December 29, 2020, were included and categorized into 2 groups: EPTS ≤20% and EPTS >20%. Cox regression was performed to evaluate the association of EPTS score and patient survival. The rate of postoperative complications, graft failure and patient survival were compared between 2 groups. Data were analyzed with SPSS v26 and R v4.0.4. The study complies with the Helsinki Congress and the Istanbul Declaration.

    RESULTS: We included 159 DDKTRs, with a median follow-up of 25 months (range, 10-60 months). The mean age of those with EPTS ≤20% was 32.2 ± 3.4 years and those with EPTS >20% was 46.0 ± 6.7 years, and the median EPTS score were 16% (range, 12%-18%) and 38% (range, 27%-56.5%), respectively. EPTS score was associated with patient survival (hazard ratio, 1.031; 95% CI 1.010-1.052; P = .003), and the cutoff points of 30% and above were associated with worse survival. It showed good discrimination (C-index, 0.729; 95% CI 0.579-0.878; P = .003) and the optimal cutoff value was 38% (65.5% sensitivity, 68.8% specificity, 17.8% positive predictive value, and 95.8% negative predictive value). Both groups had similar rate of surgical complications (P = .191), graft failure (P = .503), and patient survival (P = .654), but those with EPTS >20% had higher incidence of urinary tract infection (9.3% vs 27.6%, P = .016).

    CONCLUSIONS: There was no difference in clinical outcomes using an EPTS cutoff point of 20% but worse patient survival if higher cutoff point was used.

  6. Naji GA, Omar RA, Yahya R
    J Mech Behav Biomed Mater, 2017 03;67:135-143.
    PMID: 28006713 DOI: 10.1016/j.jmbbm.2016.12.007
    In all-ceramic systems, a high incidence of veneer chip-off has been reported in clinical studies. Coefficient of thermal expansion (CTE) behaviour is one of the factors that may increase residual stress in the interface and influence the veneer/core bond strength. Therefore, this study aimed to evaluate the effect of sodalite zeolite-infiltration on the CTE behaviour and bond strength of different all-ceramic prostheses. The case-study groups were synthesized sodalite zeolite-infiltrated alumina (IA-SOD) and synthesized sodalite zeolite-infiltrated zirconia-toughened alumina (ZTA) (IZ-SOD), while the control groups were glass-infiltrated alumina (IA-glass) and glass-infiltrated ZTA (IZ-glass). Forty cylindrical-shaped samples measuring 5 mm in diameter and 10 mm in height were tested for CTE using a thermo-mechanical analyser machine, and forty disc-shaped ceramic samples measuring 12 mm in diameter and 1.2 ± 0.2 mm in thickness were prepared using specially designed stainless steel split mould and veneered by cylinder-shaped (2 mm high × 2 mm diameter) low-fusing porcelain (Vita VM7). The veneer/core samples were sintered and tested for shear bond strength using a high precision universal testing machine. Scanning electron microscope, stereo microscope, atomic force microscope, and energy-dispersive X-ray spectroscopy were used to investigate the structural characteristics of samples at the fracture surface. The collected data were analyzed with a one-way ANOVA and Tukey HSD test (α=.05). IZ-SOD revealed highest CTE and shear bond strength values, while the IA-glass revealed the lowest values than the other groups. There was no significant difference in CTE and bond strength among IZ-SOD, IA-SOD and IZ-glass samples (p>0.05). The experimental SOD zeolite-infiltrated samples revealed higher CTE mismatch and bond strength along with a more favourable mode of failure than did the commercial glass-infiltrated samples. Sandblast technique is considered as effective conditioning procedure for enhancing the surface roughness of SOD zeolite-infiltrated frameworks which subsequently improving the bond strength.
  7. Farhan N, Al-Maleki AR, Sarih NM, Yahya R
    Bioorg Chem, 2023 Nov;140:106786.
    PMID: 37586131 DOI: 10.1016/j.bioorg.2023.106786
    Recent studies show that some metal ions, injure microbial cells in various ways due to membrane breakdown, protein malfunction, and oxidative stress. Metal complexes are suited for creating novel antibacterial medications due to their distinct mechanisms of action and the variety of three-dimensional geometries they can acquire. In this Perspective, the present study focused on new antibacterial strategies based on metal oleoyl amide complexes. Thus, oleoyl amides ligand (fatty hydroxamic acid and fatty hydrazide hydrate) with the transition metal ions named Ag (I), Co (II), Cu (II), Ni (II) and Sn (II) complexes were successfully synthesized in this study. The metals- oleoyl amide were characterized using elemental analysis, and fourier transforms infrared (FTIR) spectroscopy. The antibacterial effect of metals- oleoyl amide complexes was investigated for Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus) by analysing minimum inhibitory concentration (MIC), minimal bactericidal concentration (MBC), and scanning electron microscopy (SEM). The results showed that metal-oleoyl amide complexes have high antibacterial activity at low concentrations. This study inferred that metal oleoyl amide complexes could be utilised as a promising therapeutic antibacterial agent.
  8. 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.
  9. Tan MH, Yee SY, Yahya R
    Clin Med (Lond), 2022 Mar;22(2):169-171.
    PMID: 38589183 DOI: 10.7861/clinmed.2021-0789
    Carbamazepine remains a first-line antiepileptic medication for the treatment of partial seizures. Despite its widespread use, carbamazepine has significant neurotoxicity and hypersensitivity reactions. We report a case of a patient post-kidney transplant who was on regular carbamazepine for childhood epilepsy and developed nystagmus, diplopia and a broad-base gait after receiving diltiazem. Understanding of the interaction between diltiazem and carbamazepine is necessary to prevent the neurotoxic effects.
  10. Sahathevan S, Karupaiah T, Khor BH, Sadu Singh BK, Mat Daud ZA, Fiaccadori E, et al.
    Front Nutr, 2021;8:743324.
    PMID: 34977109 DOI: 10.3389/fnut.2021.743324
    Background: Muscle wasting, observed in patients with end-stage kidney disease and protein energy wasting (PEW), is associated with increased mortality for those on hemodialysis (HD). Oral nutritional supplementation (ONS) and nutrition counseling (NC) are treatment options for PEW but research targeting muscle status, as an outcome metric, is limited. Aim: We compared the effects of combined treatment (ONS + NC) vs. NC alone on muscle status and nutritional parameters in HD patients with PEW. Methods: This multi-center randomized, open label-controlled trial, registered under ClinicalTrials.gov (Identifier no. NCT04789031), recruited 56 HD patients identified with PEW using the International Society of Renal Nutrition and Metabolism criteria. Patients were randomly allocated to intervention (ONS + NC, n = 29) and control (NC, n = 27) groups. The ONS + NC received commercial renal-specific ONS providing 475 kcal and 21.7 g of protein daily for 6 months. Both groups also received standard NC during the study period. Differences in quadriceps muscle status assessed using ultrasound (US) imaging, arm muscle area and circumference, bio-impedance spectroscopy (BIS), and handgrip strength (HGS) methods were analyzed using the generalized linear model for repeated measures. Results: Muscle indices as per US metrics indicated significance (p < 0.001) for group × time interaction only in the ONS + NC group, with increases by 8.3 and 7.7% for quadriceps muscle thickness and 4.5% for cross-sectional area (all p < 0.05). This effect was not observed for arm muscle area and circumference, BIS metrics and HGS in both the groups. ONS + NC compared to NC demonstrated increased dry weight (p = 0.039), mid-thigh girth (p = 0.004), serum prealbumin (p = 0.005), normalized protein catabolic rate (p = 0.025), and dietary intakes (p < 0.001), along with lower malnutrition-inflammation score (MIS) (p = 0.041). At the end of the study, lesser patients in the ONS + NC group were diagnosed with PEW (24.1%, p = 0.008) as they had achieved dietary adequacy with ONS provision. Conclusion: Combination of ONS with NC was effective in treating PEW and contributed to a gain in the muscle status as assessed by the US, suggesting that the treatment for PEW requires nutritional optimization via ONS.
  11. Al-Mehana WN, Shakir RM, Yahya R, Abd Halim SN, Tiekink ER
    Acta Crystallogr Sect E Struct Rep Online, 2011 Jul 1;67(Pt 7):o1659.
    PMID: 21837059 DOI: 10.1107/S1600536811022410
    The complete mol-ecule in the title compound, C(22)H(20)N(2)O(4), is generated by the application of an inversion centre. With the exception of the terminal acetyl-ene groups [C-O-C-C = -78.02 (17)°], the remaining atoms constituting the mol-ecule are essentially coplanar. The configuration around the C=N bond [1.282 (2) Å] is E. The formation of supra-molecular chains mediated by C-H⋯O inter-actions, occurring between methyl-ene H and meth-oxy O atoms, is the most notable feature of the crystal packing.
  12. Taqui SN, Yahya R, Hassan A, Nayak N, Syed AA
    Int J Phytoremediation, 2017 Jul 03;19(7):686-694.
    PMID: 28121459 DOI: 10.1080/15226514.2017.1284746
    Fennel seed spent (FSS)-an inexpensive nutraceutical industrial spent has been used as an efficient biosorbent for the removal of Congo red (CR) from aqueous media. Results show that the conditions for maximum adsorption would be pH 2-4 and 30°C were ideal for maximum adsorption. Based on regression fitting of the data, it was determined that the Sips isotherm (R2 = 0.994, χ2 = 0.5) adequately described the mechanism of adsorption, suggesting that the adsorption occurs homogeneously with favorable interaction between layers with favorable interaction between layers. Thermodynamic analysis showed that the adsorption is favorable (negative values for ΔG°) and endothermic (ΔH° = 12-20 kJ mol-1) for initial dye concentrations of 25, 50, and 100 ppm. The low ΔH° value indicates that the adsorption is a physical process involving weak chemical interactions like hydrogen bonds and van der Waals interactions. The kinetics revealed that the adsorption process showed pseudo-second-order tendencies with the equal influence of intraparticle as well as film diffusion. The scanning electron microscopy images of FSS show a highly fibrous matrix with a hierarchical porous structure. The Fourier transform infrared spectroscopy analysis of the spent confirmed the presence of cellulosic and lignocellulosic matter, giving it both hydrophilic and hydrophobic properties. The investigations indicate that FSS is a cost-effective and efficient biosorbent for the remediation of toxic CR dye.
  13. Hammed WA, Rahman MS, Mahmud HNME, Yahya R, Sulaiman K
    Des Monomers Polym, 2017;20(1):368-377.
    PMID: 29491808 DOI: 10.1080/15685551.2016.1271086
    A soluble poly (n-vinyl carbazole)-polypyrrole (PNVC-Ppy) copolymer was prepared through oxidative chemical polymerization wherein dodecyl benzene sulfonic acid (DBSA) was used as a dopant to facilitate polymer-organic solvent interaction and ammonium persulfate (APS) was used as an oxidant. Compared with undoped PNVC-Ppy, the DBSA-doped PNVC-Ppy copolymer showed higher solubility in some selected organic solvents. The composition and structural characteristics of the DBSA-doped PNVC-Ppy were determined by Fourier transform infrared, ultraviolet-visible, and X-ray diffraction spectroscopic methods. Field emission scanning electron microscopic method was employed to observe the morphology of the DBSA-doped PNVC-Ppy copolymer. The electrical conductivity of the DBSA-doped PNVC-Ppy copolymer was measured at room temperature. The conductivity increased with increasing concentration of APS oxidant, and the highest conductivity was recorded at 0.004 mol/dm3APS at a polymerization temperature of -5 °C. The increased conductivity can be explained by the extended half-life of pyrrole free radical at a lower temperature and a gradual increase in chain length over a prolonged time due to the slow addition of APS. Furthermore, the obtained soluble copolymer exhibits unique optical and thermal properties different from those of PNVC and Ppy.
  14. Hassan MRA, Chan HK, Nordin M, Yahya R, Sulaiman WRW, Merican SAA, et al.
    Harm Reduct J, 2023 Apr 12;20(1):48.
    PMID: 37046294 DOI: 10.1186/s12954-023-00780-3
    BACKGROUND: Despite advancements in hepatitis C virus (HCV) treatment, low uptake among hard-to-reach populations remains a global issue. The current study aimed to assess the feasibility of a modified same-day test-and-treat model in improving HCV care for people who inject drugs (PWID) living in resource-constrained rural areas.

    METHODS: A pilot study was conducted in four primary healthcare (PHC) centers in Malaysia. The model's key features included on-site HCV ribonucleic acid (RNA) testing using a shared GeneXpert® system; noninvasive biomarkers for cirrhosis diagnosis; and extended care to PWID referred from nearby PHC centers and outreach programs. The feasibility assessment focused on three aspects of the model: demand (i.e., uptake of HCV RNA testing and treatment), implementation (i.e., achievement of each step in the HCV care cascade), and practicality (i.e., ability to identify PWID with HCV and expedite treatment initiation despite resource constraints).

    RESULTS: A total of 199 anti-HCV-positive PWID were recruited. They demonstrated high demand for HCV care, with a 100% uptake of HCV RNA testing and 97.4% uptake of direct-acting antiviral treatment. The rates of HCV RNA positivity (78.4%) and sustained virologic response (92.2%) were comparable to standard practice, indicating the successful implementation of the model. The model was also practical, as it covered non-opioid-substitution-therapy-receiving individuals and enabled same-day treatment in 71.1% of the participants.

    CONCLUSIONS: The modified same-day test-and-treat model is feasible in improving HCV care for rural PWID. The study finding suggests its potential for wider adoption in HCV care for hard-to-reach populations.

  15. 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.

  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. 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.
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