Displaying publications 61 - 80 of 649 in total

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  1. Idriss AA, Ahmad AK
    Bull Environ Contam Toxicol, 2015 Feb;94(2):204-8.
    PMID: 25564001 DOI: 10.1007/s00128-014-1452-x
    This study examined the concentration of heavy metals in 13 fish species. The results indicated that shellfish species (clams) have the highest metal concentrations, followed by demersal and pelagic fishes. The mean concentration of metals in clams are Zn 88.74 ± 11.98 µg/g, Cu 4.96 ± 1.06 µg/g, Pb 1.22 ± 0.19 µg/g, Cd 0.34 ± 0.04 µg/g dry wt. basis, whereas the same measure in fish tissues was 58.04 ± 18.51, 2.47 ± 1.21, 0.58 ± 0.27 and 0.17 ± 0.08 µg/g dry wt. basis. The concentrations of heavy metals in clams and fish tissues were still lower than the maximum allowable concentrations as suggested by the Malaysian Food Act (1983) and are considered safe for local human consumption.
  2. Ahmad A, Sattar MA, Rathore HA, Abdulla MH, Khan SA, Abdullah NA, et al.
    Can J Physiol Pharmacol, 2014 Dec;92(12):1029-35.
    PMID: 25403946 DOI: 10.1139/cjpp-2014-0236
    This study investigated the role of α1D-adrenoceptor in the modulation of renal haemodynamics in rats with left ventricular hypertrophy (LVH). LVH was established in Wistar-Kyoto (WKY) rats with isoprenaline (5.0 mg · (kg body mass)(-1), by subcutaneous injection every 72 h) and caffeine (62 mg · L(-1) in drinking water, daily for 14 days). Renal vasoconstrictor responses were measured for noradrenaline (NA), phenylephrine (PE), and methoxamine (ME) before and immediately after low or high dose intrarenal infusions of BMY 7378, a selective α1D-adrenoceptor blocker. The rats with LVH had higher mean arterial blood pressure and circulating NA levels, but lower renal cortical blood perfusion compared with the control group (all P < 0.05). In the LVH group, the magnitude of the renal vasoconstrictor response to ME was blunted, but not the response to NA or PE (P < 0.05), compared with the control group (LVH vs. C, 38% vs. 50%). The magnitude of the drop in the vasoconstrictor responses to NA, PE, and ME in the presence of a higher dose of BMY 7378 was significantly greater in the LVH group compared with the control group (LVH vs. C, 45% vs. 25% for NA, 52% vs. 33% for PE, 66% vs. 53% for ME, all P < 0.05). These findings indicate an impaired renal vasoconstrictor response to adrenergic agonists during LVH. In addition, the α1D-adrenoceptor subtype plays a key role in the modulation of vascular responses in this diseased state.
  3. Benhamou K, Kaddami H, Magnin A, Dufresne A, Ahmad A
    Carbohydr Polym, 2015 May 20;122:202-11.
    PMID: 25817660 DOI: 10.1016/j.carbpol.2014.12.081
    Novel bio-based polyurethane (PU) nanocomposites composed of cellulose nanofiller extracted from the rachis of date palm tree and polycaprolactone (PCL) diol based PU were prepared by casting/evaporation. Two types of nanofiber were used: cellulose nanofibrils (CNFs) and cellulose nanocrystals (CNCs). The mechanical and thermal properties of the nanocomposite films were studied by DMA, DSC, and tensile tests and the morphology was investigated by SEM. Bionanocomposites presented good mechanical properties in comparison to neat PU. While comparing both nanofillers, the improvement in mechanical and thermal properties was more pronounced for the nanocomposites based on CNF which could be explained, not only by the higher aspect ratio of CNF, but also by their better dispersion in the PU matrix. Calculation of the solubility parameters of the nanofiller surface polymers and of the PU segments portend a better interfacial adhesion for CNF based nanocomposites compared to CNC.
  4. Latifi M, Ahmad A, Hassan NH, Ben Youcef H, Kaddami H
    Carbohydr Polym, 2021 Dec 01;273:118542.
    PMID: 34560954 DOI: 10.1016/j.carbpol.2021.118542
    Carboxymethyl chitin (CMChit) has the potential to be used as a solid polymer electrolyte (SPE) based on its ionic conductivity value of the order of 10-6 S·cm-1 in self-standing membranes. In controlled humidity of 65RH%, carboxymethyl chitin based membrane blended with 1-Butyl-3-methylimidazolium acetate (BMIM[Ac]) ionic liquid (IL) (40 wt%) showed a threshold value of ionic conductivity in the order of 10-4 S·cm-1 and electrochemical stability was up to 2.93 V. The effects of the relative humidity and ionic liquid weight fraction on the ionic conductivity and structural changes were investigated in detail. Furthermore, the X-ray diffraction (XRD) diffractogram indicated a clear reduction of crystallinity of the CMChit. The Field-emission scanning electron microscopy (FESEM) observation of the cross-sections confirmed the homogeneity of the prepared blend. This electrolyte was tested in symmetric cells based on Zn//SPE//Zn and showed good reversibility and potential for application in proton-conducting batteries.
  5. Ahmad A, Razali MH, Mamat M, Mehamod FS, Anuar Mat Amin K
    Chemosphere, 2017 Feb;168:474-482.
    PMID: 27855344 DOI: 10.1016/j.chemosphere.2016.11.028
    This study aims to develop a highly efficient adsorbent material. CNTs are prepared using a chemical vapor deposition method with acetylene and synthesized mesoporous Ni-MCM41 as the carbon source and catalyst, respectively, and are then functionalized using 3-aminopropyltriethoxysilane (APTES) through the co-condensation method and loaded with commercial TiO2. Results of X-ray powder diffraction (XRD), Raman spectra, and Fourier transform infrared spectroscopy (FTIR) confirm that the synthesized CNTs grown are multi-walled carbon nanotubes (MWNTs). Transmission electron microscopy shows good dispersion of TiO2 nanoparticles onto functionalized-CNTs loaded TiO2, with the diameter of a hair-like structure measuring between 3 and 8 nm. The functionalized-CNTs loaded TiO2 are tested as an adsorbent for removal of methyl orange (MO) in aqueous solution, and results show that 94% of MO is removed after 10 min of reaction, and 100% after 30 min. The adsorption kinetic model of functionalized-CNTs loaded TiO2 follows a pseudo-second order with a maximum adsorption capacity of 42.85 mg/g. This study shows that functionalized-CNTs loaded TiO2 has considerable potential as an adsorbent material due to the short adsorption time required to achieve equilibrium.
  6. Mohd Hanafiah Z, Wan Mohtar WHM, Abd Manan TSB, Bachi' NA, Abdullah NA, Abd Hamid HH, et al.
    Chemosphere, 2022 Jan;287(Pt 2):132134.
    PMID: 34517236 DOI: 10.1016/j.chemosphere.2021.132134
    The water stream has been reported to contain non-steroidal anti-inflammatory drugs (NSAIDs), released from households and premises through discharge from Sewage Treatment Plant (STP). This research identifies commonly consumed NSAIDs namely ibuprofen (IBU), diclofenac (DIC), ketoprofen (KET) and naproxen (NAP) in the influent wastewater from two urban catchments (i.e. 2 STPs). We expand our focus to assess the efficiency of monomer (C18) and dimer (HLB) types of sorbents in the solid phase extraction method followed by gas chromatography mass spectrometry (GCMS) analysis and optimize model prediction of NSAIDs in the influent wastewater using I-Optimal design. The ecological risk assessment of the NSAIDs was evaluated. The HLB produced reliable analysis for all NSAIDs under study (STP1: 6.7 × 10-3 mg L-1 to 2.21 × 10-1 mg L-1, STP2: 1.40 × 10-4 mg L-1 to 9.72 × 10-2 mg L-1). The C18 however, selective to NAP. Based on the Pearson proximity matrices, the DICHLB can be a good indicator for IBUHLB (0.565), NAPC18 (0.721), NAPHLB (0.566), and KETHLB (0.747). The optimized model prediction for KET and NAP based on DIC are successfully validated. The risk quotients (RQ) values of NSAIDs were classified as high (RQ > 1), medium (RQ, 0.1-1) and low (RQ, 0.01-0.1) risks. The optimized models are beneficial for major NSAIDs (KET and NAP) monitoring in the influent wastewater of urban domestic area. An upgrade on the existing wastewater treatment infrastructure is recommended to counteract current water security situation.
  7. Ahmad A, Kurniawan SB, Abdullah SRS, Othman AR, Hasan HA
    Chemosphere, 2022 Mar;290:133319.
    PMID: 34922971 DOI: 10.1016/j.chemosphere.2021.133319
    The contamination of aquaculture products and effluents by contaminants of emerging concern (CECs) from the direct chemical use in aquaculture activities or surrounding industries is currently an issue of increasing concern as these CECs exert acute and chronic effects on living organisms. CECs have been detected in aquaculture water, sediment, and culture species, and antibiotics, antifoulants, and disinfectants are the commonly detected groups. Through accumulation, CECs can reside in the tissue of aquaculture products and eventually consumed by humans. Currently, effluents containing CECs are discharged to the surrounding environment while producing sediments that eventually contaminate rivers as receiving bodies. The rearing (grow-out) stages of aquaculture activities are issues regarding CECs-contamination in aquaculture covering water, sediment, and aquaculture products. Proper regulations should be imposed on all aquaculturists to control chemical usage and ensure compliance to guidelines for appropriate effluent treatment. Several techniques for treating aquaculture effluents contaminated by CECs have been explored, including adsorption, wetland construction, photocatalysis, filtration, sludge activation, and sedimentation. The challenges imposed by CECs on aquaculture activities are discussed for the purpose of obtaining insights into current issues and providing future approaches for resolving associated problems. Stakeholders, such as researchers focusing on environment and aquaculture, are expected to benefit from the presented results in this article. In addition, the results may be useful in establishing aquaculture-related CECs regulations, assessing toxicity to living biota, and preventing pollution.
  8. Nazar M, Ul Hassan Shah M, Ahmad A, Goto M, Zaireen Nisa Yahya W, Moniruzzaman M
    Chemosphere, 2023 Dec;344:140412.
    PMID: 37827466 DOI: 10.1016/j.chemosphere.2023.140412
    Chemical dispersants are extensively used for marine oil spill remediation. However, the increased toxicity and low biodegradability of these dispersants restrict their employment in the marine environment. Hence, in this work, we have developed an eco-friendly formulation composed of an ionic liquid,1-butyl-3-methylimidazolium lauroyl sarcosinate [BMIM][Lausar] and sorbitan monooleate (Span) 80. Micellar and interfacial parameters, dispersion effectiveness, as well as the toxicity and biodegradability of the developed formulation were investigated. Micellar properties confirmed a high degree of synergism among the surfactant molecules and the formation of stable micelle. The dispersion effectiveness, at dispersant-to-oil ratio (DOR) of 1:25 (v/v), against three crude oils (Arab, Ratawi, and Doba) was assessed. We achieved a dispersion effectiveness of 68.49%, 74.05%, and 83.43% for Ratawi, Doba, and Arab crude oil, respectively, using a 70:30 (w/w) ratio of Span 80 to [BMIM][Lausar]. Furthermore, the results obtained from optical microscopy and particle size analysis (PSA) indicated that the oil droplet size decreased with higher DOR. Additionally, acute toxicity experiments were conducted on zebrafish (Danio rerio) using the developed formulation, confirming its non-toxic behavior, with LC50 values of 800 mg/L after 96 h. The formulation also exhibited high biodegradability, with only 25.01% of the original quantity remaining after 28 days. Hence, these results suggest that the new formulation has the potential to be a highly effective and environmentally friendly dispersant for oil spill remediation.
  9. Khairuddin F, Zaharah Mohd Fuzi SF, Ahmad A, Oon LK, Bokhari A, Dailin DJ, et al.
    Chemosphere, 2024 Feb;350:141007.
    PMID: 38141667 DOI: 10.1016/j.chemosphere.2023.141007
    Recent advancement in biophotovoltaic systems using microalgae, coupled with biorefinery approach, would improve economy-feasibility in production. The major concern is its commercial strength in terms of scalability, strain selection and extraction procedure cost. It must compete with conventional feedstocks such as fossil fuels. This project proposes to enhance the economic feasibility of microalgae-based biorefinery by evaluating their performance for bio-electricity, bio-diesel and carotenoids production in a single cycle. The first part of the study was to construct and select a Bio-bottle Voltaic (BBV) device that would allow microalgae to grow and produce bioproducts, as well as generate the maximum current output reading derived from the microalgae's photosynthesis process. The second phase consisted of a 25-day investigation into the biorefinery performance of six different microalgal species in producing bio-electricity, bio-diesel and carotenoid in a prototype BBV device. The prototype BBV device with aluminium foil and pencil lead as its anode and cathode produced the highest carotenoid and biodiesel component production from the two microalgae tested, according to the results of the first phase of the experiment. In the second portion of the study, Scenedesmus dimorphus and Chlorella vulgaris were identified as the two microalgae most capable of maintaining their growth throughout the experiment. The maximum current reading observed for C. vulgaris was 653 mV. High Performance Liquid Chromatography analysis showed four major carotenoid compounds found which were Neoxanthin, Cantaxanthin, Astaxanthin and 9-cis antheraxanthin, and the highest carotenoid producer was C. vulgaris which recorded at 1.73 μg/mL. C. vulgaris recorded as the most alkanes producer with 22 compounds detected and Heptacosane and Heneicosane as the two major biodiesel compounds found in the extracts. Evaluation of C. vulgaris data showed that it has enormous potential for microalgal biorefinery candidates. Further ongoing research and development efforts for C. vulgaris will improve the economic viability of microalgae-based industries and reduce reliance on depleted fossil fuels.
  10. Abdullah MI, Ahmad A, Syed Saadun Tarek Wafa SWW, Abdul Latif AZ, Mohd Yusoff NA, Jasmiad MK, et al.
    Chin J Traumatol, 2020 Oct;23(5):290-294.
    PMID: 32423779 DOI: 10.1016/j.cjtee.2020.04.004
    PURPOSE: Malnutrition is a common problem among hospitalized patients, especially among traumatic brain injury (TBI) patients. It is developed from hypermetabolism and the condition may worsen under the circumstance of underfeeding or incompatible dietary management. However, the data of nutrient intake especially calorie and protein among TBI patients were scarce. Hence, this study aimed to determine the calorie and protein intake among acute and sub-acute TBI patients receiving medical nutrition therapy in hospital Sultanah Nur Zahirah, Terengganu.

    METHODS: This observational study involved 50 patients recruited from the neurosurgical ward. Method of 24 h dietary recall was utilized and combined with self-administered food diaries for 2-8 days. Food consumptions including calorie intake and protein intake were analyzed using Nutritionist PRO™ (Woodinville, USA) and manual calculation based on the Malaysian food composition database (2015).

    RESULTS: Patients consisted of 56% males and 44% females with the median age of 28.0 (IQR = 22.8-36.5) years, of which 92% were diagnosed as mild TBI and the remaining (8%) as moderate TBI. The Glasgow coma scale (GCS) was adopted to classify TBI severity with the score 13-15 being mild and 9-12 being moderate. The median length of hospital stay was 2 (IQR = 2.0-3.3) days. Calorie and protein intake improved significantly from day 1 to discharge day. However, the intake during discharge day was still considered as suboptimal, i.e. 75% of calorie requirement, whilst the median protein intake was only 61.3% relative to protein requirement. Moreover, the average percentages of calorie and protein intakes throughout hospitalization were remarkably lower, i.e. 52.2% and 41.0%, respectively.

    CONCLUSION: Although the calorie and protein intakes had increased from baseline, hospitalized TBI patients were still at a risk to develop malnutrition as the average intakes were considerably low as compared to their requirements. Optimum nutrient intakes especially calorie and protein are crucial to ensure optimum recovery process as well as to minimize risks of infection and complications.

  11. Misron K, Hamid SSA, Ahmad A, Ramli RR
    Clin Exp Otorhinolaryngol, 2017 Sep;10(3):241-247.
    PMID: 28449554 DOI: 10.21053/ceo.2016.01732
    OBJECTIVES: This case-controlled study aimed to identify the association of tumor necrosis factor (TNF)α-1031 and TNFβ+ 252 gene polymorphisms between chronic rhinosinusitis (CRS) and healthy controls. Another purpose of this study was to investigate the associations of these gene polymorphisms with factors related to CRS.

    METHODS: All deoxyribonucleic acid (DNA) samples were genotyped for TNFα-1031 and TNFβ+252 genes by mean of polymerase chain reaction (PCR) and restriction fragment length polymorphisms (RFLP). The statistical analysis were carried out using chi-square test or Fisher exact test to determine the associations of these gene polymorphisms in CRS. Multiple logistic regression was performed to evaluate the associations of these gene polymorphisms in CRS and its related risk factors.

    RESULTS: The genotype and allele frequencies of TNFα-1031 and TNFβ+252 gene did not show any significant associations between CRS and healthy controls. However, a significantly statistical difference of TNFα-1031 was observed in CRS participants with atopy (P-value, 0.045; odds ratio, 3.66) but not in CRS with asthma or aspirin intolerance.

    CONCLUSION: Although the presence of TNFα-1031 and TNFβ+252 gene polymorphisms did not render any significant associations between CRS and healthy control, this study suggests that TNFα-1031 gene polymorphisms in CRS patients with atopy may be associated with increase susceptibility towards CRS.

  12. Marzo RR, Ismail Z, Nu Htay MN, Bahari R, Ismail R, Villanueva EQ, et al.
    PMID: 33619459 DOI: 10.1016/j.cegh.2021.100708
    The COVID-19 pandemics caused an unprecedented mortality, distress, and globally poses a challenge to mental resilience. To our knowledge, this is the first study that aimed to investigate the psychological distress among the adult general population across 13 countries. This cross-sectional study was conducted through online survey by recruiting 7091 respondents. Psychological distress was evaluated with COVID-19 Peritraumatic Distress Index (CPDI). The crude prevalence of psychological distress due to COVID-19 is highest in Vietnam, followed by Egypt, and Bangladesh. Through Multivariate Logistic Regression Analysis, the respondents from Vietnam holds the highest level of distress, while the respondents from Sri Lanka holds the lowest level of distress with reference to Nepal.Female respondents had higher odds of having reported psychological distress, and those with tertiary education were less likely to report psychological distress compared to those with lower level of education. The findings indicate that psychological distress is varies across different countries. Therefore, different countries should continue the surveillance on psychological consequences through the COVID-19 pandemic to monitor the burden and to prepare for the targeted mental health support interventions according to the need. The coping strategies and social support should be provided especially to the lower educational attainment group.
  13. Lew LC, Hor YY, Yusoff NAA, Choi SB, Yusoff MSB, Roslan NS, et al.
    Clin Nutr, 2019 10;38(5):2053-2064.
    PMID: 30266270 DOI: 10.1016/j.clnu.2018.09.010
    BACKGROUND & AIMS: To investigate the effects of probiotic in alleviation of stress in stressed adults, along our focus to identify and justify strain specificity on selected health benefits with a precisely targeted population.

    METHODS: This 12-weeks randomized, double-blind and placebo-controlled study investigated the effects of a probiotic (Lactobacillus plantarum P8; 10 log CFU daily) on psychological, memory and cognition parameters in one hundred and three (P8 n = 52, placebo n = 51) stressed adults with mean age of 31.7 ± 11.1 years old. All subjects fulfilled the criteria of moderate stress upon diagnosis using the PSS-10 questionnaire.

    RESULTS: At the end of study, subjects on P8 showed reduced scores of stress (mean difference 2.94; 95% CI 0.08 to 5.73; P = 0.048), anxiety (mean difference 2.82; 95% CI 0.35 to 5.30; P = 0.031) and total score (mean difference 8.04; 95% CI 0.73 to 15.30; P = 0.041) as compared to placebo after 4-weeks, as assessed by the DASS-42 questionnaire. Although plasma cortisol levels were only marginally different between placebo and P8 (mean difference 3.28 ug/dl; 95% CI -7.09 to 0.52; P = 0.090), pro-inflammatory cytokines such as IFN-γ (mean difference 8.07 pg/ml; 95% CI -11.2 to -4.93; P 

  14. Ahmad A, Mohd-Ali B, Ishak B
    Clin Optom (Auckl), 2018;10:109-113.
    PMID: 30319302 DOI: 10.2147/OPTO.S172272
    Purpose: Soft contact lens wear is most frequently associated with morphologic changes in corneal endothelial cells, but the data are scarce in Asians. This study aimed to evaluate changes in corneal endothelial cell morphology after 6 months of wearing soft hydrogel contact lenses (SH) in young myopic adults living in Kuala Lumpur.

    Patients and methods: Forty-eight subjects were included in the study, 24 were fitted with SH contact lenses (A) and the rest were prescribed with glasses (B). Refraction was conducted subjectively and standard contact lens fitting protocol was followed. Corneal endothelial cell morphology (endothelial cell density, ECD; coefficient of variation, COV; cells' hexagonality, HEX; and central corneal thickness, CCT) was evaluated using specular microscope. Data were collected at baseline and after 6 months of lens wear.

    Results: Mean age of all subjects was 21.23±1.30 years. All results are shown at baseline and 6 months, respectively. Mean refraction for A was -2.16±0.97 diopter sphere (DS) and -2.05±1.03 DS (P=0.49); for B was -2.72±1.51 DS and -2.73±1.51 DS (P=0.58). Mean ECD (cell/mm2) for A: 3104.19±237.30 and 3107.23±237.51 (P=0.07); for B: 3011.56±227.95 and 2983.83±244.55 (P=0.33). COV (%) for A: 46.52±8.63 and 48.53±10.65 (P=0.06); for B: 46.93±9.31 and 46.14±10.65 (P=0.88). HEX (%) for A: 46.21±10.12 and 45.15±10.01 (P=0.08); for B: 46.21±10.12 and 45.15±10.01 (P=0.12). CCT (µm) for A: 520.33±0.04 and 525.70±0.05 (P=0.41); for B: 532.00±0.04 µm and 530.00±0.05 µm (P=0.40).

    Conclusion: This study found no significant change in corneal endothelial cell morphology after 6 months of wearing SH contact lenses. This is probably due to better oxygen permeability of the contact lens material, good compliance, and short wearing period.
  15. Umpleby AM, Shojaee-Moradie F, Fielding B, Li X, Marino A, Alsini N, et al.
    Clin Sci (Lond), 2017 Nov 01;131(21):2561-2573.
    PMID: 28923880 DOI: 10.1042/CS20171208
    Dietary sugars are linked to the development of non-alcoholic fatty liver disease (NAFLD) and dyslipidaemia, but it is unknown if NAFLD itself influences the effects of sugars on plasma lipoproteins. To study this further, men with NAFLD (n = 11) and low liver fat 'controls' (n = 14) were fed two iso-energetic diets, high or low in sugars (26% or 6% total energy) for 12 weeks, in a randomised, cross-over design. Fasting plasma lipid and lipoprotein kinetics were measured after each diet by stable isotope trace-labelling.There were significant differences in the production and catabolic rates of VLDL subclasses between men with NAFLD and controls, in response to the high and low sugar diets. Men with NAFLD had higher plasma concentrations of VLDL1-triacylglycerol (TAG) after the high (P<0.02) and low sugar (P<0.0002) diets, a lower VLDL1-TAG fractional catabolic rate after the high sugar diet (P<0.01), and a higher VLDL1-TAG production rate after the low sugar diet (P<0.01), relative to controls. An effect of the high sugar diet, was to channel hepatic TAG into a higher production of VLDL1-TAG (P<0.02) in the controls, but in contrast, a higher production of VLDL2-TAG (P<0.05) in NAFLD. These dietary effects on VLDL subclass kinetics could be explained, in part, by differences in the contribution of fatty acids from intra-hepatic stores, and de novo lipogenesis. The present study provides new evidence that liver fat accumulation leads to a differential partitioning of hepatic TAG into large and small VLDL subclasses, in response to high and low intakes of sugars.
  16. Rabbani G, Khan MJ, Ahmad A, Maskat MY, Khan RH
    Colloids Surf B Biointerfaces, 2014 Nov 1;123:96-105.
    PMID: 25260221 DOI: 10.1016/j.colsurfb.2014.08.035
    The primary objective of this study is to explore the interaction of β-galactosidase with copper oxide nanoparticles (CuO NPs). Steady-state absorption, fluorescence and circular dichroism (CD) spectroscopic techniques have been employed to unveil the conformational changes of β-galactosidase induced by the binding of CuO NPs. Temperature dependent fluorescence quenching results indicates a static quenching mechanism in the present case. The binding thermodynamic parameters delineate the predominant role of H-bonding and van der Waals forces between β-galactosidase and CuO NPs binding process. The binding was studied by isothermal titration calorimetry (ITC) and the result revealed that the complexation is enthalpy driven, the ΔH°<0, ΔS°<0 indicates the formation of hydrogen bonds between β-galactosidase and CuO NPs occurs. Disruption of the native conformation of the protein upon binding with CuO NPs is reflected through a reduced functionality (in terms of hydrolase activity) of the protein CuO NPs conjugate system in comparison to the native protein and CuO NPs exhibited a competitive mode of inhibition. This also supports the general belief that H-bond formation occurs with NPs is associated with a lesser extent of modification in the native structure. Morphological features and size distributions were investigated using transmission electron microscopy (TEM) and dynamic light scattering (DLS). Additionally the considerable increase in the Rh following the addition of CuO NPs accounts for the unfolding of β-galactosidase. Chemical and thermal unfolding of β-galactosidase, when carried out in the presence of CuO NPs, also indicated a small perturbation in the protein structure. These alterations in functional activity of nanoparticle bound β-galactosidase which will have important consequences should be taken into consideration while using nanoparticles for diagnostic and therapeutic purposes.
  17. Oladoja NA, Adelagun RO, Ahmad AL, Unuabonah EI, Bello HA
    Colloids Surf B Biointerfaces, 2014 May 1;117:51-9.
    PMID: 24632030 DOI: 10.1016/j.colsurfb.2014.02.006
    A novel adsorbent, magnetic, macro-reticulated cross-linked chitosan (MRC) was synthesised for the removal of tetracycline (TC) from water using a source of biogenic waste (gastropod shells) as a pore-forming agent. The insertion of crosslinks into the chitosan frame was confirmed by FTIR analysis, while the stability of the MRC was demonstrated via a stability test performed in an acidic solution. The enhanced porosity of the MRC was confirmed by the evaluation of its porosity, a swelling test and the determination of its specific surface area. The time-concentration profile of the sorption of TC onto the MRC demonstrated that equilibrium was attained relatively quickly (120 min), and the data obtained fitted a pseudo second order (r(2)>0.99) kinetic equation better than a pseudo first order or reversible first order kinetic equation. The optimisation of process variables indicated that the sorption of TC onto the MRC was favoured at a low solution pH and that the presence of organics (simulated by the addition of humic acid) negatively impacted the magnitude of TC removal. The area of coverage of TC on the MRC (2.51 m(2)/g) was low compared to the specific surface area of the MRC (47.95 m(2)/g). The value of the calculated energy of adsorption of TC onto the MRC was 100 kJ/mol, which is far above the range of 1-16 kJ/mol stipulated for physical adsorption.
  18. Low SC, Shaimi R, Thandaithabany Y, Lim JK, Ahmad AL, Ismail A
    Colloids Surf B Biointerfaces, 2013 Oct 1;110:248-53.
    PMID: 23732801 DOI: 10.1016/j.colsurfb.2013.05.001
    Protein adsorption onto membrane surfaces is important in fields related to separation science and biomedical research. This study explored the molecular interactions between protein, bovine serum albumin (BSA), and nitrocellulose films (NC) using electrokinetic phenomena and the effects of these interactions on the streaming potential measurements for different membrane pore morphologies and pH conditions. The data were used to calculate the streaming ratios of membranes-to-proteins and to compare these values to the electrostatic or hydrophobic attachment of the protein molecules onto the NC membranes. The results showed that different pH and membrane pore morphologies contributes to different protein adsorption mechanisms. The protein adsorption was significantly reduced under conditions where the membrane and protein have like-charges due to electrostatic repulsion. At the isoelectric point (IEP) of the protein, the repulsion between the BSA and the NC membrane was at the lowest; thus, the BSA could be easily attached onto the membrane/solution interface. In this case, the protein was considered to be in a compact layer without intermolecular protein repulsions.
  19. Ahmad A, Lim LL, Morieri ML, Tam CH, Cheng F, Chikowore T, et al.
    Commun Med (Lond), 2024 Jan 22;4(1):11.
    PMID: 38253823 DOI: 10.1038/s43856-023-00429-z
    BACKGROUND: Precision medicine has the potential to improve cardiovascular disease (CVD) risk prediction in individuals with Type 2 diabetes (T2D).

    METHODS: We conducted a systematic review and meta-analysis of longitudinal studies to identify potentially novel prognostic factors that may improve CVD risk prediction in T2D. Out of 9380 studies identified, 416 studies met inclusion criteria. Outcomes were reported for 321 biomarker studies, 48 genetic marker studies, and 47 risk score/model studies.

    RESULTS: Out of all evaluated biomarkers, only 13 showed improvement in prediction performance. Results of pooled meta-analyses, non-pooled analyses, and assessments of improvement in prediction performance and risk of bias, yielded the highest predictive utility for N-terminal pro b-type natriuretic peptide (NT-proBNP) (high-evidence), troponin-T (TnT) (moderate-evidence), triglyceride-glucose (TyG) index (moderate-evidence), Genetic Risk Score for Coronary Heart Disease (GRS-CHD) (moderate-evidence); moderate predictive utility for coronary computed tomography angiography (low-evidence), single-photon emission computed tomography (low-evidence), pulse wave velocity (moderate-evidence); and low predictive utility for C-reactive protein (moderate-evidence), coronary artery calcium score (low-evidence), galectin-3 (low-evidence), troponin-I (low-evidence), carotid plaque (low-evidence), and growth differentiation factor-15 (low-evidence). Risk scores showed modest discrimination, with lower performance in populations different from the original development cohort.

    CONCLUSIONS: Despite high interest in this topic, very few studies conducted rigorous analyses to demonstrate incremental predictive utility beyond established CVD risk factors for T2D. The most promising markers identified were NT-proBNP, TnT, TyG and GRS-CHD, with the highest strength of evidence for NT-proBNP. Further research is needed to determine their clinical utility in risk stratification and management of CVD in T2D.

  20. Shahab M, Iqbal MW, Ahmad A, Alshabrmi FM, Wei DQ, Khan A, et al.
    Comput Biol Med, 2024 Mar;170:108056.
    PMID: 38301512 DOI: 10.1016/j.compbiomed.2024.108056
    The Nipah virus (NPV) is a highly lethal virus, known for its significant fatality rate. The virus initially originated in Malaysia in 1998 and later led to outbreaks in nearby countries such as Bangladesh, Singapore, and India. Currently, there are no specific vaccines available for this virus. The current work employed the reverse vaccinology method to conduct a comprehensive analysis of the entire proteome of the NPV virus. The aim was to identify and choose the most promising antigenic proteins that could serve as potential candidates for vaccine development. We have also designed B and T cell epitopes-based vaccine candidate using immunoinformatics approach. We have identified a total of 5 novel Cytotoxic T Lymphocytes (CTL), 5 Helper T Lymphocytes (HTL), and 6 linear B-cell potential antigenic epitopes which are novel and can be used for further vaccine development against Nipah virus. Then we performed the physicochemical properties, antigenic, immunogenic and allergenicity prediction of the designed vaccine candidate against NPV. Further, Computational analysis indicated that these epitopes possessed highly antigenic properties and were capable of interacting with immune receptors. The designed vaccine were then docked with the human immune receptors, namely TLR-2 and TLR-4 showed robust interaction with the immune receptor. Molecular dynamics simulations demonstrated robust binding and good dynamics. After numerous dosages at varied intervals, computational immune response modeling showed that the immunogenic construct might elicit a significant immune response. In conclusion, the immunogenic construct shows promise in providing protection against NPV, However, further experimental validation is required before moving to clinical trials.
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