Displaying publications 1 - 20 of 50 in total

Abstract:
Sort:
  1. Fulltext Biodiesel synthesis catalyzed by transition metal oxides: ferric-manganese doped tungstated/molybdena nanoparticle catalyst
    Alhassan FH, Rashid U, Taufiq-Yap YH
    J Oleo Sci, 2015;64(1):91-9.
    PMID: 25492234 DOI: 10.5650/jos.ess14161
    The solid acid Ferric-manganese doped tungstated/molybdena nananoparticle catalyst was prepared via impregnation reaction followed by calcination at 600°C for 3 h. The characterization was done using X-ray diffraction (XRD), Raman spectroscopy, thermal gravimetric analysis (TGA), temperature programmed desorption of NH3 (TPD-NH3), X-ray fluorescence (XRF), Transmission electron microscope (TEM) and Brunner-Emmett-Teller surface area measurement (BET). Moreover, dependence of biodiesel yield on the reaction variables such as the reaction temperature, catalyst loading, as well as molar ratio of methanol/oil and reusability were also appraised. The catalyst was reused six times without any loss in activity with maximum yield of 92.3% ±1.12 achieved in the optimized conditions of reaction temperature of 200°C; stirring speed of 600 rpm, 1:25 molar ratio of oil to alcohol, 6 % w/w catalyst loading as well as 8 h as time of the reaction. The fuel properties of WCOME's were evaluated, including the density, kinematic viscosity, pour point, cloud point and flash point whereas all properties were compared with the limits in the ASTM D6751 standard.
  2. Fulltext Synthesis of waste cooking oil based biodiesel via ferric-manganese promoted molybdenum oxide / zirconia nanoparticle solid acid catalyst: influence of ferric and manganese dopants
    Alhassan FH, Rashid U, Taufiq-Yap YH
    J Oleo Sci, 2015;64(5):505-14.
    PMID: 25843280 DOI: 10.5650/jos.ess14228
    The utilization of ferric-manganese promoted molybdenum oxide/zirconia (Fe-Mn- MoO3/ZrO2) (FMMZ) solid acid catalyst for production of biodiesel was demonstrated. FMMZ is produced through impregnation reaction followed by calcination at 600°C for 3 h. The characterization of FMMZ had been done using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), temperature programmed desorption of NH3 (TPD-NH3), transmission electron microscopy(TEM) and Brunner-Emmett-Teller (BET) surface area measurement. The effect of waste cooking oil methyl esters (WCOME's) yield on the reactions variables such as reaction temperature, catalyst loading, molar ratio of methanol/oil and reusability were also assessed. The catalyst was used to convert the waste cooking oil into corresponding methyl esters (95.6%±0.15) within 5 h at 200℃ reaction temperature, 600 rpm stirring speed, 1:25 molar ratio of oil to alcohol and 4% w/w catalyst loading. The reported catalyst was successfully recycled in six connective experiments without loss in activity. Moreover, the fuel properties of WCOME's were also reported using ASTM D 6751 methods.
  3. Application of activated carbon from banana stem waste for removal of heavy metal ions in greywater using a Box-Behnken design approach
    Praveena SM, Rashid U, Rashid SA
    Environ Technol, 2020 Nov;41(25):3363-3374.
    PMID: 31002023 DOI: 10.1080/09593330.2019.1609590
    There is limited information on the optimal processes to remove heavy metals in greywater. A Response Surface Methodology (RSM) via the Box-Behnken Design (BBD) approach was applied in this study to investigate and optimise the process variables of activation time (1.5-2.5 h), impregnation ratio (0.25-0.75) and zinc chloride (ZnCl2) percentage (20-60%) for the removal of heavy metal ions (Cd, Cu, Pb and Ni) associated with greywater treatment. The quadratic model was chosen to describe the effects of the process variables (activation time, impregnation ratio, ZnCl2 percentage) on predicting the responses (heavy metal ions removal) with low p-values (
  4. Rational design of bis-indolylmethane-oxadiazole hybrids as inhibitors of thymidine phosphorylase
    Taha M, Rashid U, Imran S, Ali M
    Bioorg Med Chem, 2018 07 23;26(12):3654-3663.
    PMID: 29853339 DOI: 10.1016/j.bmc.2018.05.046
    Inhibition of Thymidine phosphorylase (TP) is continuously studied for the design and development of new drugs for the treatment of neoplastic diseases. As a part of our effort to identify TP inhibitors, we performed a structure-based virtual screening (SBVS) of our compound collection. Based on the insights gained from structures of virtual screening hits, a scaffold was designed using 1,3,4-oxadiazole as the basic structural feature and SAR studies were carried out for the optimization of this scaffold. Twenty-five novel bis-indole linked 1,3,4-oxadiazoles (7-31) were designed, synthesized and tested in vitro against E. coli TP (EcTP). Compound 7 emerged as potent TP inhibitor with an IC50 value of 3.50 ± 0.01 μM. Docking studies were carried out using GOLD software on thymidine phosphorylase from human (hTP) and E. coli (EcTP). Various hydrogen bonding, hydrophobic interactions, and π-π stacking were observed between designed molecules and the active site amino acid residues of the studied enzymes.
  5. Biomedical Applications of Aromatic Azo Compounds
    Ali Y, Hamid SA, Rashid U
    Mini Rev Med Chem, 2018;18(18):1548-1558.
    PMID: 29792144 DOI: 10.2174/1389557518666180524113111
    Azo dyes are widely used in textile, fiber, cosmetic, leather, paint and printing industries. Besides their characteristic coloring function, azo compounds are reported as antibacterial, antiviral, antifungal and cytotoxic agents. They have the ability to be used as drug carriers, either by acting as a 'cargo' that entrap therapeutic agents or by prodrug approach. The drug is released by internal or external stimuli in the region of interest, as observed in colon-targeted drug delivery. Besides drug-like and drug carrier properties, a number of azo dyes are used in cellular staining to visualize cellular components and metabolic processes. However, the biological significance of azo compounds, especially in cancer chemotherapy, is still in its infancy. This may be linked to early findings that declared azo compounds as one of the possible causes of cancer and mutagenesis. Currently, researchers are screening the aromatic azo compounds for their potential biomedical use, including cancer diagnosis and therapy. In this review, we highlight the medical applications of azo compounds, particularly related to cancer research. The biomedical significance of cis-trans interchange and negative implications of azo compounds are also discussed in brief.
  6. Fulltext Dynamic modeling of reversible methanolysis of Jatropha curcas oil to biodiesel
    Syam AM, Hamid HA, Yunus R, Rashid U
    ScientificWorldJournal, 2013;2013:268385.
    PMID: 24363616 DOI: 10.1155/2013/268385
    Many kinetics studies on methanolysis assumed the reactions to be irreversible. The aim of the present work was to study the dynamic modeling of reversible methanolysis of Jatropha curcas oil (JCO) to biodiesel. The experimental data were collected under the optimal reaction conditions: molar ratio of methanol to JCO at 6 : 1, reaction temperature of 60°C, 60 min of reaction time, and 1% w/w of catalyst concentration. The dynamic modeling involved the derivation of differential equations for rates of three stepwise reactions. The simulation study was then performed on the resulting equations using MATLAB. The newly developed reversible models were fitted with various rate constants and compared with the experimental data for fitting purposes. In addition, analysis of variance was done statistically to evaluate the adequacy and quality of model parameters. The kinetics study revealed that the reverse reactions were significantly slower than forward reactions. The activation energies ranged from 6.5 to 44.4 KJ mol⁻¹.
  7. A bibliometric study of the top 100 most-cited randomized controlled trials, systematic reviews and meta-analyses published in endodontic journals
    Ahmad P, Dummer PMH, Chaudhry A, Rashid U, Saif S, Asif JA
    Int Endod J, 2019 Sep;52(9):1297-1316.
    PMID: 31009099 DOI: 10.1111/iej.13131
    AIM: To identify and analyse the main features of the top 100 most-cited randomized controlled trials, systematic reviews and meta-analyses published in endodontic journals from 1961 to 2018.

    METHODOLOGY: The Clarivate Analytics' Web of Science 'All Databases' was used to search and analyse the 100 most frequently cited randomized controlled trials, systematic reviews and meta-analyses having 'randomized', 'randomised', 'randomized controlled', 'randomised controlled', 'randomized controlled trial', 'randomized controlled trials', 'clinical trial', 'systematic', 'systematic review', 'meta-analysis', and 'meta-analyses' in the title section. The 'International Endodontic Journal', 'Journal of Endodontics', 'Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontology', 'Australian Endodontic Journal', 'Endodontics & Dental Traumatology', 'Endo-Endodontic Practice Today' and 'European Endodontic Journal' were included in the publication name section. After ranking the articles in a descending order based on their citation counts, each article was cross-matched with the citation counts in Elsevier's Scopus and Google Scholar. The articles were analysed, and information on citation counts, citation density, year of publication, contributing authors, institutions and countries, journal of publication, study design, topic of the article and keywords was extracted.

    RESULTS: The citation counts of the 100 most-cited articles varied from 235 to 20 (Web of Science), 276 to 17 (Scopus) and 696 to 1 (Google Scholar). The year in which the top 100 articles were published was 2010 (n = 13). Among 373 authors, the greatest number of articles was associated with three individuals namely Reader A (n = 5), Beck M (n = 5) and Kvist T (n = 5). Most of the articles originated from the United States (n = 24) with the greatest contribution from Ohio State University (USA) (n = 5). Randomized controlled trials were the most frequent study design (n = 45) followed by systematic reviews (n = 30) with outcome studies of root canal treatment being the major topic (n = 35). The Journal of Endodontics published the largest number of included articles (n = 70) followed by the International Endodontic Journal (n = 27). Among 259 unique keywords, meta-analysis (n = 23) and systematic review (n = 23) were the most frequently used.

    CONCLUSION: This study has revealed that year of publication had no obvious impact on citation count. The bibliometric analysis highlighted the quantity and quality of research, and the evolution of scientific advancements made in the field of Endodontology over time. Articles before 1996, that is prior to the CONSORT statement that encouraged authors to include specific terms in the title and keywords, may not have been included in this electronic search.

  8. Fulltext Development and Characterization of Polypropylene Waste from Personal Protective Equipment (PPE)-Derived Char-Filled Sugar Palm Starch Biocomposite Briquettes
    Harussani MM, Sapuan SM, Rashid U, Khalina A
    Polymers (Basel), 2021 May 24;13(11).
    PMID: 34073691 DOI: 10.3390/polym13111707
    Slow pyrolysis using a batch reactor at 450 °C was applied to the polypropylene (PP) powder derived from Coronavirus Disease 2019 (COVID-19) isolation gown waste to yield char briquettes, using sugar palm starch (SPS) and a manual hydraulic press. These studies are significant because of reductions in plastic waste from the preparation of barbecue coal due to environmental sustainability. The results presented here include the physical, morphological, thermal, combustion, and mechanical properties of char when reinforced with various percentages of SPS loadings (0, 10, 20, 30, and 40%), which act as a matrix/binder to produce char/sugar palm starch (C/SPS) composites. The physical and morphological characteristics of C/SPS composites were determined using Fourier transform infrared (FTIR) and field emission scanning electron microscopy (FESEM). On the other hand, the thermal and combustion properties of the C/SPS briquettes were studied via thermogravimetric and bomb calorimeter analysis. The results show that the compressive strength of the briquettes increased as the SPS loading increased, whereas the higher heating values (HHV) reduced. The findings indicate that C-80/SPS-20 briquettes presented excellent combustion characteristics (1,761,430 J/g) with satisfactory mechanical strength (1.463 MPa) in the compression test. Thus, C-80/SPS-20 briquettes are the most suitable composites for domestic and commercial uses.
  9. Fulltext N-Arylation of Protected and Unprotected 5-Bromo-2-aminobenzimidazole as Organic Material: Non-Linear Optical (NLO) Properties and Structural Feature Determination through Computational Approach
    Mumtaz M, Rasool N, Ahmad G, Kosar N, Rashid U
    Molecules, 2021 Nov 17;26(22).
    PMID: 34834012 DOI: 10.3390/molecules26226920
    The interest in the NLO response of organic compounds is growing rapidly, due to the ease of synthesis, availability, and low loss. Here, in this study, Cu(II)-catalyzed selective N-arylation of 2-aminobenzimidazoles derivatives were achieved in the presence of different bases Et3N/TMEDA, solvents DCM/MeOH/H2O, and various aryl boronic acids under open atmospheric conditions. Two different copper-catalyzed pathways were selected for N-arylation in the presence of active nucleophilic sites, providing a unique tool for the preparation of NLO materials, C-NH (aryl) derivatives of 2-aminobenzimidazoles with protection and without protection of NH2 group. In addition to NMR analysis, all synthesized derivatives (1a-1f and 2a-2f) of 5-bromo-2-aminobenzimidazole (1) were computed for their non-linear optical (NLO) properties and reactivity descriptor parameters. Frontier molecular orbital (FMO) analysis was performed to get information about the electronic properties and reactivity of synthesized compounds.
  10. Fulltext Conversion of Waste Polyethylene Terephthalate (PET) Polymer into Activated Carbon and Its Feasibility to Produce Green Fuel
    Ahangar FA, Rashid U, Ahmad J, Tsubota T, Alsalme A
    Polymers (Basel), 2021 Nov 16;13(22).
    PMID: 34833251 DOI: 10.3390/polym13223952
    In this study, a novel idea was proposed to convert the polyethylene terephthalate (PET) waste drinking-water bottles into activated carbon (AC) to use for waste cooking oil (WCO) and palm fatty acid distillate (PFAD) feasibility to convert into esters. The acidic and basic char were prepared by using the waste PET bottles. The physiochemical properties were determined by employing various analytical techniques, such as field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR), Brunauer-Emmett-Teller (BET) and temperature-programmed desorption - ammonia/carbon dioxide (TPD-NH3/CO2). The prepared PET H3PO4 and PET KOH showed the higher surface area, thus illustrating that the surface of both materials has enough space for impregnation of foreign precursors. The TPD-NH3 and TPD-CO2 results depicted that PET H3PO4 is found to have higher acidity, i.e., 18.17 mmolg-1, due to the attachment of phosponyl groups to it during pretreatment, whereas, in the case of PET KOH, the basicity increases to 13.49 mmolg-1. The conversion results show that prepared materials can be used as a support for an acidic and basic catalyst for the conversion of WCO and PFAD into green fuel.
  11. Palm-Based Neopentyl Glycol Diester: A Potential Green Insulating Oil
    Raof NA, Yunus R, Rashid U, Azis N, Yaakub Z
    Protein Pept Lett, 2018;25(2):171-179.
    PMID: 29359647 DOI: 10.2174/0929866525666180122095056
    BACKGROUND: The transesterification of high oleic palm oil methyl ester (HOPME) with neopentyl glycol (NPG) has been investigated. The present study revealed the application of low-pressure technology as a new synthesis method to produce NPG diesters. Single variable optimization and response surface methodology (RSM) were implemented to optimize the experimental conditions to achieve the maximum composition (wt%) of NPG diesters.

    OBJECTIVE: The main objective of this study was to optimize the production of NPG diesters and to characterize the optimized esters with typical chemical, physical and electrical properties to study its potential as insulating oil.

    METHODS: The transesterification reaction between HOPME and NPG was conducted in a 1L three-neck flask reactor at specified temperature, pressure, molar ratio and catalyst concentration. For the optimization, four factors have been studied and the diester product was characterized by using gas chromatography (GC) analysis. The synthesized esters were then characterized with typical properties of transformer oil such as flash point, pour point, viscosity and breakdown voltage and were compared with mineral insulating oil and commercial NPG dioleate. For formulation, different samples of NPG diesters with different concentration of pour point depressant were prepared and each sample was tested for its pour point measurement.

    RESULTS: The optimum conditions inferred from the analyses were: molar ratio of HOPME to NPG of 2:1.3, temperature = 182°C, pressure = 0.6 mbar and catalyst concentration of 1.2%. The synthesized NPG diesters showed very important improvement in fire safety compared to mineral oil with flash point of 300°C and 155°C, respectively. NPG diesters also exhibit a relatively good viscosity of 21 cSt. The most striking observation to emerge from the data comparison with NPG diester was the breakdown voltage, which was higher than mineral oil and definitely in conformance to the IEC 61099 limit at 67.5 kV. The formulation of synthesized NPD diesters with VISCOPLEX® pour point depressant has successfully increased the pour point of NPG diester from -14°C to -48°C.

    CONCLUSION: The reaction time for the transesterification of HOPME with NPG to produce NPG diester was successfully reduced to 1 hour from the 14 hours required in the earlier synthesis method. The main highlight of this study was the excess reactant which is no longer methyl ester but the alcohol (NPG). The optimum reaction conditions for the synthesis were molar ratio of 2:1.13 for NPG:HOPME, 182°C, 0.6 mbar and catalyst concentration of 1.2 wt%. The maximum NPG diester yield of 87 wt% was consistent with the predicted yield of 87.7 wt% obtained from RSM. The synthesized diester exhibited better insulating properties than the commercial products especially with regards to the breakdown voltage, flash point and moisture content.

  12. Fulltext Pyrolysis of polypropylene plastic waste into carbonaceous char: Priority of plastic waste management amidst COVID-19 pandemic
    Harussani MM, Sapuan SM, Rashid U, Khalina A, Ilyas RA
    Sci Total Environ, 2022 Jan 10;803:149911.
    PMID: 34525745 DOI: 10.1016/j.scitotenv.2021.149911
    COVID-19 global pandemic, originated from Wuhan, resulted in a massive increase in the output of polypropylene (PP)-based personal protective equipment (PPE) for healthcare workers. The continuous demand of PPE across the world caused the PP based plastic wastes accumulation. Some alternative approaches that have been practiced apart from collecting the plastic waste in the landfills are incineration approach and open burning. However, there were many drawbacks of these practices, which promote the release of chemical additives and greenhouse gases into the environment. Therefore, a proper approach in treating the plastic wastes, which introduces conversion of plastic wastes into renewable energy is paramount. Along the way of extensive research and studies, the recovery of PP plastic to fuel-like liquid oil and solid char through thermal decomposition of pyrolysis process, helps in reducing the number of PP plastic wastes and produces good quality pyrolysis liquid oil and solid char to be used in fuel applications. This paper summarizes the pyrolysis process for massively produced PP plastic wastes, type of pyrolysis used and the main pyrolysis parameters affecting the product yields. Literature studies of pyrolysis of PP plastic and several key points to optimize solid char production for PP were thoroughly elaborated in this review paper.
  13. Fulltext Low-Temperature Thermal Degradation of Disinfected COVID-19 Non-Woven Polypropylene-Based Isolation Gown Wastes into Carbonaceous Char
    Harussani MM, Rashid U, Sapuan SM, Abdan K
    Polymers (Basel), 2021 Nov 17;13(22).
    PMID: 34833277 DOI: 10.3390/polym13223980
    Yields of carbonaceous char with a high surface area were enhanced by decreasing the temperature to improve the conversion of hazardous plastic polypropylene (PP), the major component in abundantly used isolation gowns. This study applied pyrolysis with different low pyrolytic temperatures to convert disinfected PP-based isolation gown waste (PP-IG) into an optimised amount of char yields. A batch reactor with a horizontal furnace was used to mediate the thermal decomposition of PP-IG. Enhanced surface area and porosity value of PP-IG derived char were obtained via an optimised slow pyrolysis approach. The results showed that the amount of yielded char was inversely proportional to the temperature. This process relied heavily on the process parameters, especially pyrolytic temperature. Additionally, as the heating rate decreased, as well as longer isothermal residence time, the char yields were increased. Optimised temperature for maximum char yields was recorded. The enhanced SBET values for the char and its pore volume were collected, ~24 m2 g-1 and ~0.08 cm3 g-1, respectively. The char obtained at higher temperatures display higher volatilisation and carbonisation. These findings are beneficial for the utilisation of this pyrolysis model in plastic waste management and conversion of PP-IG waste into char for further activated carbon and fuel briquettes applications, with the enhanced char yields, amidst the COVID-19 pandemic.
  14. Fulltext Palm oil derived trimethylolpropane triesters synthetic lubricants and usage in industrial metalworking fluid
    Chang TS, Yunus R, Rashid U, Choong TS, Awang Biak DR, Syam AM
    J Oleo Sci, 2015;64(2):143-51.
    PMID: 25748374 DOI: 10.5650/jos.ess14162
    Trimethylolpropane triesters are biodegradable synthetic lubricant base oil alternative to mineral oils, polyalphaolefins and diesters. These oils can be produced from trimethylolpropane (TMP) and fatty acid methyl esters via chemical or enzymatic catalyzed synthesis methods. In the present study, a commercial palm oil derived winter grade biodiesel (ME18) was evaluated as a viable and sustainable methyl ester source for the synthesis of high oleic trimethylolpropane triesters (HO-TMPTE). ME18 has fatty acid profile containing 86.8% oleic acid, 8.7% linoleic acid with the remaining minor concentration of palmitic acid, stearic acid and linolenic acid. It's high oleic property makes it superior to produce synthetic lubricant base oil that fulfills both the good low temperature property as well as good oxidative stability. The synthetic base oil produced had a viscosity of 44.3 mm(2)/s at 40°C meeting the needs for ISO 46 oils. It also exhibited an excellent viscosity index of 219 that is higher than some other commercial brands of trimethylolpropane trioleate. Properties of base oil such as cloud point, density, acid value, demulsibility and soap content were also examined. The oil was then used in the formulation of tapping oil and appraised in term of adaptability, stability and field test performance.
  15. Microwave-assisted biodiesel production by esterification of palm fatty acid distillate
    Lokman IM, Rashid U, Zainal Z, Yunus R, Taufiq-Yap YH
    J Oleo Sci, 2014;63(9):849-55.
    PMID: 25099911
    In the current research work, effect of microwave irradiation energy on the esterification of palm fatty acid distillate (PFAD) to produce PFAD methyl ester / biodiesel was intensively appraised. The PFAD is a by-product from refinery of crude palm oil consisting >85% of free fatty acid (FFA). The esterification reaction process with acid catalyst is needed to convert the FFA into fatty acid methyl ester or known as biodiesel. In this work, fabricated microwave-pulse width modulation (MPWM) reactor with controlled temperature was designed to be capable to increase the PFAD biodiesel production rate. The classical optimization technique was used in order to study the relationship and the optimum condition of variables involved. Consequently, by using MPWM reactor, mixture of methanol-to-PFAD molar ratio of 9:1, 1 wt.% of sulfuric acid catalyst, at 55°C reaction temperature within 15 min reaction time gave 99.5% of FFA conversion. The quality assessment and properties of the product were analyzed according to the American Society for Testing and Materials (ASTM), European (EN) standard methods and all results were in agreement with the standard requirements. It revealed that the use of fabricated MPWM with controlled temperature was significantly affecting the rate of esterification reaction and also increased the production yield of PFAD methyl ester.
  16. Synthesis of 2-acylated and sulfonated 4-hydroxycoumarins: In vitro urease inhibition and molecular docking studies
    Rashid U, Rahim F, Taha M, Arshad M, Ullah H, Mahmood T, et al.
    Bioorg Chem, 2016 Jun;66:111-6.
    PMID: 27140727 DOI: 10.1016/j.bioorg.2016.04.005
    Sixteen 4-hydroxycoumarin derivatives were synthesized, characterized through EI-MS and (1)H NMR and screened for urease inhibitory potential. Three compounds exhibited better urease inhibition than the standard inhibitor thiourea (IC50=21±0.11μM) while other four compounds exhibited good to moderate inhibition with IC50 values between 29.45±1.1μM and 69.53±0.9μM. Structure activity relationship was established on the basis of molecular docking studies, which helped to predict the binding interactions of the most active compounds.
  17. Fulltext Pharmacist-led counselling intervention to improve antiretroviral drug adherence in Pakistan: a randomized controlled trial
    Chatha ZF, Rashid U, Olsen S, Din FU, Khan A, Nawaz K, et al.
    BMC Infect Dis, 2020 Nov 23;20(1):874.
    PMID: 33228562 DOI: 10.1186/s12879-020-05571-w
    BACKGROUND: Pakistan is facing a growing population of people living with human immunodeficiency (HIV). In this randomized controlled trial, we investigate if a pharmacist-led intervention can increase adherence to antiretroviral therapy (ART) for people living with HIV (PLWH).

    METHODS: Adults with HIV, who have been taking ART for more than 3 months were randomly assigned to receive either a pharmacist-led intervention or their usual care. Measures of adherence were collected at 1) baseline 2) just prior to delivery of intervention and 3) 8 weeks later. The primary outcomes were CD4 cell count and self-reported adherence measured with the AIDS Clinical Trial Group (ACTG) questionnaire.

    RESULTS: Post-intervention, the intervention group showed a statistically significant increase in CD4 cell counts as compared to the usual care group (p = 0.0054). In addition, adherence improved in the intervention group, with participants being 5.96 times more likely to report having not missed their medication for longer periods of time (p = 0.0086) while participants in the intervention group were 7.74 times more likely to report missing their ART less frequently (p 

  18. Fulltext An acceleration of microwave-assisted transesterification of palm oil-based methyl ester into trimethylolpropane ester
    Aziz NAM, Yunus R, Hamid HA, Ghassan AAK, Omar R, Rashid U, et al.
    Sci Rep, 2020 11 12;10(1):19652.
    PMID: 33184363 DOI: 10.1038/s41598-020-76775-y
    Microwave-assisted synthesis is known to accelerate the transesterification process and address the issues associated with the conventional thermal process, such as the processing time and the energy input requirement. Herein, the effect of microwave irradiation on the transesterification of palm oil methyl ester (PME) with trimethylolpropane (TMP) was evaluated. The reaction system was investigated through five process parameters, which were reaction temperature, catalyst, time, molar ratio of TMP to PME and vacuum pressure. The yield of TMP triester at 66.9 wt.% and undesirable fatty soap at 17.4% were obtained at 130 °C, 10 mbar, sodium methoxide solution at 0.6 wt.%, 10 min reaction time and molar ratio of TMP to PME at 1:4. The transesterification of palm oil-based methyl ester to trimethylolpropane ester was 3.1 folds faster in the presence of microwave irradiation. The total energy requirement was markedly reduced as compared to the conventional heating method. The findings indicate that microwave-assisted transesterification could probably be an answer to the quest for a cheaper biodegradable biolubricant.
  19. Goat milk attenuates mimetic aging related memory impairment via suppressing brain oxidative stress, neurodegeneration and modulating neurotrophic factors in D-galactose-induced aging model
    Safdar A, Zakaria R, Aziz CBA, Rashid U, Azman KF
    Biogerontology, 2020 04;21(2):203-216.
    PMID: 31792648 DOI: 10.1007/s10522-019-09854-x
    One of the most significant hallmarks of aging is cognitive decline. D-galactose administration may impair memory and mimic the effects of natural aging. In this study, the efficiency of goat milk to protect against memory decline was tested. Fifty-two male Sprague-Dawley rats were randomly divided into four groups: (i) control group, (ii) goat milk treated group, (iii) D-galactose treated group, and (iv) goat milk plus D-galactose treated group. Subcutaneous injections of D-galactose at 120 mg/kg and oral administrations of goat milk at 1 g/kg were chosen for the study. Goat milk and D-galactose were administered concomitantly for 6 weeks, while the control group received saline. After 6 weeks, novel object recognition and T-maze tests were performed to evaluate memory of rats. Following behavioral tests, the animals were sacrificed, and right brain homogenates were analyzed for levels of lipid peroxidation, antioxidant enzymes and neurotrophic factors. The left brain hemisphere was used for histological study of prefrontal cortex and hippocampus. There was a significant memory impairment, an increase in oxidative stress and neurodegeneration and a reduction in antioxidant enzymes and neurotrophic factors levels in the brain of D-galactose treated rats compared to controls. Goat milk treatment attenuated memory impairment induced by D-galactose via suppressing oxidative stress and neuronal damage and increasing neurotrophic factors levels, thereby suggesting its potential role as a geroprotective food.
  20. Fulltext Role of Pyridine Nitrogen in Palladium-Catalyzed Imine Hydrolysis: A Case Study of (E)-1-(3-bromothiophen-2-yl)-N-(4-methylpyridin-2-yl)methanimine
    Ahmad G, Rasool N, Rizwan K, Altaf AA, Rashid U, Mahmood T, et al.
    Molecules, 2019 Jul 17;24(14).
    PMID: 31319634 DOI: 10.3390/molecules24142609
    In the present study, 4-methylpyridin-2-amine was reacted with 3-bromothiophene-2-carbaldehyde and the Schiff base (E)-1-(3-bromothiophen-2-yl)-N-(4-methylpyridin-2-yl)methanimine was obtained in a 79% yield. Coupling of the Schiff base with aryl/het-aryl boronic acids under Suzuki coupling reaction conditions, using Pd(PPh3)4 as catalyst, yielded products with the hydrolysis of the imine linkages (5a-5k, 6a-6h) in good to moderate yields. To gain mechanistic insight into the transition metal-catalyzed hydrolysis of the compounds, density functional theory (DFT) calculations were performed. The theoretical calculations strongly supported the experiment and provided an insight into the transition metal-catalyzed hydrolysis of imines.
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links