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  1. Fulltext Two-Step Purification of Glycerol as a Value Added by Product From the Biodiesel Production Process
    Abdul Raman AA, Tan HW, Buthiyappan A
    Front Chem, 2019;7:774.
    PMID: 31799239 DOI: 10.3389/fchem.2019.00774
    For every ton of biodiesel produced, about 100 kg of glycerol is also generated as a by-product. The traditional method of removing glycerol is mainly by gravity separation or centrifugation. This method generates crude glycerol, which may still contain impurities such as methanol, oil, soap, salt, and other organic materials at ppm levels. The effective usage of crude glycerol is important to improve the economic sustainability of the biodiesel industry while reducing the environmental impacts caused by the generated waste. The application and value of crude glycerol can be enhanced if these impurities are removed or minimized. Thus, it is important to develop a method which can increase the economic and applicable value of crude glycerol. Therefore, in the present study, the dual step purification method comprised of acidification and ion exchange techniques has been used to purify the crude glycerol and convert it into higher-value products. The acidification process started with the pH adjustment of the crude glycerol, using phosphoric acid to convert soap into fatty acid and salts. Then, the pretreated glycerol was further purified by ion exchange with a strong cation H+ resin. Gas chromatography (GC) was used to analyze both crude and purified glycerol and expressed as the weight percentage of glycerol content. A maximum glycerol purity of 98.2% was obtained after the dual step purification method at the optimized conditions of 60% of solvent, the flow rate of 15 mL/min and 40 g of resin. Further, the glycerol content measured being within the accepted amount of BS 2621:1979. Therefore, this study has proven that the proposed crude glycerol purification process is effective in improving the glycerol purity and could enhance the applicability of glycerol in producing value-added products which bring new revenue to the biodiesel industry.
    Matched MeSH terms: Hydrogen-Ion Concentration
  2. Synthesis of chitosan-ethylene glycol diglycidyl ether/TiO2 nanoparticles for adsorption of reactive orange 16 dye using a response surface methodology approach
    Abdulhameed AS, Jawad AH, Mohammad AT
    Bioresour Technol, 2019 Dec;293:122071.
    PMID: 31491651 DOI: 10.1016/j.biortech.2019.122071
    Chitosan-ethylene glycol diglycidyl ether/TiO2 nanoparticles (CS-EGDE/TNP) composite was synthesized to be biosorbent for the removal of reactive orange 16 (RO16) dye from aqueous solution. The CS-EGDE/TNP composite was characterized via BET, XRD, FTIR, and SEM-EDX techniques. Response surface methodology (RSM) with Box-Behnken design (BBD) was applied to optimize the adsorption key parameters such as adsorbent dose (A: 0.02-0.08 g/L), RO16 dye concentration (B: 20-80 mg/L), solution pH (C: 4-10), temperature (D: 30-50 °C), and contact time (E: 30-90 min). The adsorption isotherm followed Freundlich model and pseudo-second order (PSO) kinetic model. The adsorption capacity of CS-EGDE/TNP for RO16 dye was 1407.4 mg/g at 40 °C. The adsorption mechanism of RO16 dye on the surface of CS-EGDE/TNP can be attributed to various interactions such as electrostatic attraction, n-π interaction, Yoshida H-bonding, and H-bonding. Results supported the potential use of CS-EGDE/TNP as effective adsorbent for the treatment of acid reactive dye.
    Matched MeSH terms: Hydrogen-Ion Concentration
  3. Biomagnetic chitosan-ethylene glycol diglycidyl ether/organo-nanoclay nanocomposite for azo dye removal: A statistical modeling by response surface methodology
    Abdulhameed AS, Hapiz A, Musa SA, ALOthman ZA, Wilson LD, Jawad AH
    Int J Biol Macromol, 2024 Jan;255:128075.
    PMID: 37977465 DOI: 10.1016/j.ijbiomac.2023.128075
    Herein, a quadruple biomagnetic nanocomposite of cross-linked chitosan-ethylene glycol diglycidyl ether/organo-nanoclay (MCH-EGDE/ORNC) was designed for the uptake of remazol brilliant blue R (RBBR) dye from aqueous environment. The adsorption process was systematically improved via the Box-Behnken design (BBD) to determine the influence of key uptake parameters, including MCH-EGDE/ORNC dosage, pH, and time, on the RBBR removal. The highest RBBR removal of 87.5 % was achieved at the following conditions: MCH-EGDE/ORNC dosage: 0.1 g/100 mL; pH: 4.0; contact time: 25 min. The findings of the kinetics and equilibrium studies revealed an excellent fit to the pseudo-second order and the Freundlich models, respectively. The adsorption capacity of the MCH-EGDE/ORNC for RBBR was found to be 168.4 mg/g, showcasing its remarkable adsorption capability. The present work highlights the potential of MCH-EGDE/ORNC biomaterial as an advanced adsorbent and lays the foundation for future applications in water purification and environmental remediation.
    Matched MeSH terms: Hydrogen-Ion Concentration
  4. Organically modified montmorillonite composited with magnetic glyoxal-chitosan Schiff base for reactive blue 19 dye removal: Process optimization and adsorptive mechanism
    Abdulhameed AS, Hapiz A, Musa SA, Kashi E, Wu R, ALOthman ZA, et al.
    Int J Biol Macromol, 2024 Jan;256(Pt 2):128463.
    PMID: 38029908 DOI: 10.1016/j.ijbiomac.2023.128463
    In this study, a new biocomposite magnetic adsorbent (magnetic glyoxal-chitosan Schiff base/organically modified montmorillonite (MCTS-GOX/OMMT)) was synthesized and employed for the adsorption of reactive blue 19 dye (RB19) from aqueous environment. The physicochemical properties of the MCTS-GOX/OMMT were confirmed by using various characterization techniques such as BET, XRD, FTIR, SEM-EDX, VSM, and pHpzc. The adsorption key variables were statistically optimized via Box-Behnken design (BBD) And accordingly the best operational conditions to achieve maximum RB19 removal were recorded at MCTS-GOX/OMMT dosage = 0.1 g/0.1 L, solution pH = 4, and working temperature = 25 °C. The adsorption process for RB19 appeared to follow the pseudo-second-order kinetic and the Langmuir isotherm models, according to the findings of the adsorption kinetics and equilibrium investigations. The maximum adsorption capacity of the MCTS-GOX/OMMT towards RB19 was 122.3 mg/g, demonstrating its preferable adsorption capability. The successful development of this novel magnetic bioadsorbent with excellent adsorption ability towards organic dyes and efficient separation ability opens possibilities for its practical application in wastewater treatment and dye removal processes.
    Matched MeSH terms: Hydrogen-Ion Concentration
  5. Bisphenol-A-diglycidyl ether modified chitosan/nano-SiO2 via hydrothermal process: A statistical modeling and adsorption mechanism for reactive orange 16 dye removal
    Abdulhameed AS, Wu R, Musa SA, Agha HM, ALOthman ZA, Jawad AH, et al.
    Int J Biol Macromol, 2024 Jan;256(Pt 1):128267.
    PMID: 37992917 DOI: 10.1016/j.ijbiomac.2023.128267
    In this study, chitosan/nano SiO2 (CTS/NS) was chemically modified with bisphenol A diglycidyl ether (BADGE) cross-linker-assisted hydrothermal process to create an effective adsorbent, CTS-BADGE/NS, for the removal of reactive orange 16 (RO16) dye from aquatic systems. Box-Behnken design (BBD) was used to optimize the adsorption process by varying the adsorbent dose (0.02-0.1 g/100 mL), pH (4-10), and time (20-360 min). The adsorption isotherm results indicated that the Langmuir model fits the experimental data well, suggesting that the adsorption process involves a monolayer formation of RO16 on the surface of CTS-BADGE/NS. The kinetic modeling of RO16 adsorption by CTS-BADGE/NS demonstrated that the pseudo-first-order model fits the adsorption data. CTS-BADGE/NS achieved an adsorption capacity of 97.8 mg/g for RO16 dye at optimum desirability functions of dosage 0.099 g/100 mL, solution pH of 4.44, and temperature of 25 °C. Overall, the π-π electron donor-acceptor system significantly improved the adsorption performance of the CTS-BADGE/NS. The results of the regeneration investigation demonstrate that the CTS-BADGE/NS exhibits effective adsorption of RO16, even after undergoing five consecutive cycles. The results of this study suggest that the developed CTS-BADGE/NS composite can be a promising adsorbent for water purification applications.
    Matched MeSH terms: Hydrogen-Ion Concentration
  6. Fulltext Effects of salivary pH on coating durability of two different aesthetic archwire coatings under a simulated intraoral environment
    Abdulkader YC, Kamaruddin AF, Mydin RBSMN
    Saudi Dent J, 2020 Sep;32(6):306-313.
    PMID: 32874071 DOI: 10.1016/j.sdentj.2019.09.010
    Objectives: This study compared the effects of normal salivary pH, and acidic pH found in patients with poor oral hygiene, on the durability of aesthetic archwire coated with epoxy resin and polytetrafluoroethylene (PTFE).

    Methods: The posterior parts of the archwires were sectioned into 20 mm segments (N = 102) and divided among six groups. Four groups were treated with different pH levels and two served as controls. The specimens were immersed in individual test tubes containing 10 ml of artificial saliva adjusted to a pH of 6.75 or 3.5. The tubes were sealed and stored in a 37 °C water bath for 28 days. After 28 days, the specimens were ligated to brackets embedded in an acrylic block and subjected to mechanical stress using an electronic toothbrush for 210 s. The specimens were photographed, and images were measured for coating loss using AutoCAD® software. Surface morphology was observed using a scanning electron microscope (SEM).

    Results: Significant coating loss (p 

    Matched MeSH terms: Hydrogen-Ion Concentration
  7. Study of surface activity of piroxicam at the interface of palm oil esters and various aqueous phases
    Abdulkarim MF, Abdullah GZ, Chitneni M, Yam MF, Mahdi ES, Salman IM, et al.
    Pak J Pharm Sci, 2012 Apr;25(2):429-33.
    PMID: 22459473
    The surface activity of some non-steroidal anti-inflammatory agents like ibuprofen was investigated extensively. This fact has attracted the researchers to extend this behavior to other agents like piroxicam. Piroxicam molecules are expected to orient at the interface of oil and aqueous phase. The aim of this study was, firstly, to assess the surface and interfacial tension behaviour of newly synthesised palm oil esters and various pH phosphate buffers. Furthermore, the surface and interfacial tension activity of piroxicam was studied. All the measurements of surface and interfacial tension were made using the tensiometer. The study revealed that piroxicam has no effect on surface tension values of all pH phosphate buffers and palm oil esters. Similarly, various concentrations of piroxicam did not affect the interfacial tensions between the oil phase and the buffer phases. Accordingly, the interfacial tension values of all mixtures of oil and phosphate buffers were considerably high which indicates the immiscibility. It could be concluded that piroxicam has no surface activity. Additionally, there is no surface pressure activity of piroxicam at the interface of plam oil esters and phosphate buffers in the presence of Tweens and Spans.
    Matched MeSH terms: Hydrogen-Ion Concentration
  8. Signal grass (Brachiaria decumbens) toxicity in sheep: changes in motility and pH of reticulo-rumen
    Abdullah AS, Nordin MM, Rajion MA
    Vet Hum Toxicol, 1988 Jun;30(3):256-8.
    PMID: 3388753
    In addition to generalized icterus, enlargement of the liver and severe photosensitization, signal grass (Brachiaria decumbens) toxicity also caused ruminal stasis and a decreased rumen pH in sheep. Ruminal stasis, which occurred within 3 weeks of grazing on this grass, may be the effect of the toxin produced in the rumen rather than a sequele of a decreased rumen pH. Animals were anorexic and the volume of their rumen content was very much reduced.
    Matched MeSH terms: Hydrogen-Ion Concentration
  9. Preparation and in vitro evaluation of mebeverine HCl colon-targeted drug delivery system
    Abdullah GZ, Abdulkarim MF, Chitneni M, Mutee AF, Ameer OZ, Salman IM, et al.
    Pharm Dev Technol, 2011 Aug;16(4):331-42.
    PMID: 20429815 DOI: 10.3109/10837451003739255
    Mebeverine HCl is a water soluble drug commonly used to treat irritable bowel syndrome by acting directly on the smooth muscles of the colon. This work was aimed at the formulation and in vitro evaluation of a colon-targeted drug delivery system containing mebeverine HCl. Matrix tablets were prepared using ethyl cellulose (EC), Eudragit RL 100 either solely or in combination by wet granulation technique. Dissolution was carried out in 0.1 N HCl for 2?h followed by pH 6.8 phosphate buffer for eight hours. Uncoated forms released more than 5% drug in 0.1 N HCl therefore, Eudragit L100 was used as a coat. The results indicated very slow release profile. As a result, single retardant was used to prepare the matrix and coated by Eudragit L 100. The matrix containing 7% Eudragit RL 100 and 6% of binder was subjected to further studies to assess the effect of different coats (Eudragit L 100-55 and cellulose acetate phthalate) and different binders (pectin and sodium alginate) on the release profile. Eudragit L 100 and pectin were the best coating agent and binder, respectively. The final formula was stable and it can be concluded that the prepared system has the potential to deliver mebeverine HCl in vivo to the colon.
    Matched MeSH terms: Hydrogen-Ion Concentration
  10. Carbopol 934, 940 and Ultrez 10 as viscosity modifiers of palm olein esters based nano-scaled emulsion containing ibuprofen
    Abdullah GZ, Abdulkarim MF, Mallikarjun C, Mahdi ES, Basri M, Sattar MA, et al.
    Pak J Pharm Sci, 2013 Jan;26(1):75-83.
    PMID: 23261730
    Micro-emulsions and sometimes nano-emulsions are well known candidates to deliver drugs locally. However, the poor rheological properties are marginally affecting their acceptance pharmaceutically. This work aimed to modify the poor flow properties of a nano-scaled emulsion comprising palm olein esters as the oil phase and ibuprofen as the active ingredient for topical delivery. Three Carbopol ® resins: 934, 940 and Ultrez 10, were utilized in various concentrations to achieve these goals. Moreover, phosphate buffer and triethanolamine solutions pH 7.4 were used as neutralizing agents to assess their effects on the gel-forming and swelling properties of Carbopol ® 940. The addition of these polymers caused the produced nano-scaled emulsion to show a dramatic droplets enlargement of the dispersed globules, increased intrinsic viscosity, consistent zeta potential and transparent-to-opaque change in appearance. These changes were relatively influenced by the type and the concentration of the resin used. Carbopol ® 940 and triethanolamine appeared to be superior in achieving the proposed tasks compared to other materials. The higher the pH of triethanolamine solution, the stronger the flow-modifying properties of Carbopol ® 940. Transmission electron microscopy confirmed the formation of a well-arranged gel network of Carbopol ® 940, which was the major cause for all realized changes. Later in vitro permeation studies showed a significant decrease in the drug penetration, thus further modification using 10% w/w menthol or limonene as permeation promoters was performed. This resulted in in vitro and in vivo pharmacodynamics properties that are comparably higher than the reference chosen for this study.
    Matched MeSH terms: Hydrogen-Ion Concentration
  11. Fulltext Sustainable Development of Enhanced Luminescence Polymer-Carbon Dots Composite Film for Rapid Cd2+ Removal from Wastewater
    Abdullah Issa M, Z Abidin Z
    Molecules, 2020 Aug 03;25(15).
    PMID: 32756377 DOI: 10.3390/molecules25153541
    As a remedy for environmental pollution, a versatile synthetic approach has been developed to prepare polyvinyl alcohol (PVA)/nitrogen-doped carbon dots (CDs) composite film (PVA-CDs) for removal of toxic cadmium ions. The CDs were first synthesized using carboxymethylcellulose (CMC) of oil palms empty fruit bunch wastes with the addition of polyethyleneimine (PEI) and then the CDs were embedded with PVA. The PVA-CDs film possess synergistic functionalities through increasing the content of hydrogen bonds for chemisorption compared to the pure CDs. Optical analysis of PVA-CDs film was performed by ultraviolet-visible and fluorescence spectroscopy. Compared to the pure CDs, the solid-state PVA-CDs displayed a bright blue color with a quantum yield (QY) of 47%; they possess excitation-independent emission and a higher Cd2+ removal efficiency of 91.1%. The equilibrium state was achieved within 10 min. It was found that adsorption data fit well with the pseudo-second-order kinetic and Langmuir isotherm models. The maximum adsorption uptake was 113.6 mg g-1 at an optimal pH of 7. Desorption experiments showhe that adsorbent can be reused fruitfully for five adsorption-desorption cycles using 0.1 HCl elution. The film was successfully applied to real water samples with a removal efficiency of 95.34% and 90.9% for tap and drinking water, respectively. The fabricated membrane is biodegradable and its preparation follows an ecofriendly green route.
    Matched MeSH terms: Hydrogen-Ion Concentration
  12. Methylene blue removal by using pectin-based hydrogels extracted from dragon fruit peel waste using gamma and microwave radiation polymerization techniques
    Abdullah MF, Azfaralariff A, Lazim AM
    J Biomater Sci Polym Ed, 2018 10;29(14):1745-1763.
    PMID: 29989528 DOI: 10.1080/09205063.2018.1489023
    This research aims to compare the ability of smart hydrogel in removing the methylene blue prepared by using two different radiation methods. The extracted pectin from the dragon fruit peel (Hylocereus polyrhizus) was used with acrylic acid (AA) to produce a polymerized hydrogel through gamma and microwave radiation. The optimum hydrogel swelling capacity was obtained by varying the dose of radiation, pectin to AA ratio and pH used. From the array of samples, the ideal hydrogel was obtained at pH 8 with a ratio of 2:3 (pectin: AA) using 10 kGy and 400 W radiated gamma and microwave respectively. The performance of both hydrogels namely as Pc/AA(G) (gamma) and Pc/AA(Mw) (microwave) were investigated using methylene blue (MB) adsorption studies. In this study, three variables were manipulated, pH and MB concentration and hydrogel mass in order to find the optimum condition for the adsorption. Results showed that 20 mg of Pc/AA(G) performed the highest MB removal which was about 45% of 20 mg/L MB at pH 8. While 30 mg of Pc/AA(Mw) able to remove up to 35% of 20 mg/L MB at the same pH condition. To describe the adsorption mechanism, both kinetic models pseudo-first-order, pseudo-second-order were employed. The results from kinetic data showed that it fitted the pseudo-first-order as compared to pseudo-second-order model equation. This study provides alternative of green, facile and affective biomaterial for dye absorbents that readily available.
    Matched MeSH terms: Hydrogen-Ion Concentration
  13. Geoaccumulation Index and Enrichment Factor of Arsenic in Surface Sediment of Bukit Merah Reservoir, Malaysia
    Abdullah MIC, Sah ASRM, Haris H
    Trop Life Sci Res, 2020 Oct;31(3):109-125.
    PMID: 33214859 DOI: 10.21315/tlsr2020.31.3.8
    An investigation study was conducted in Bukit Merah Reservoir (BMR) for the assessment of arsenic concentration in the surface sediment in 23 sampling stations. The sediment samples were digested and analysed for arsenic using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Sediment parameters such as pH (4.42 ± 0.71), redox potential (121.77 ± 42.45 mV), conductivity (205.7 ± 64.07 μS cm-1) and organic matter (25.35 ± 9.34%) were also examined. The main objectives of this study are to determine the arsenic distribution and concentration and at the same time to assess the enrichment of arsenic using the geoaccumulation index (I
    geo
    ) and enrichment factor (EF). This study shows the total arsenic concentration in the surface sediment of BMR is 4.302 ± 2.43 mg kg-1 and found to be below the threshold value of Canadian Interim Sediment Quality Guidelines (ISQG). High arsenic concentration is recorded near the southern part of the lake where anthropogenic activities are prevalent. Based on I
    geo
    , 13% of sampling stations are categorised as moderately polluted, 52.2% as unpolluted to moderately polluted and the rest is categorised as unpolluted. EF shows 78.3% stations are classified as extremely high enrichment and the rest as very high enrichment. This finding provides important information on the status of arsenic contamination in BMR and creating awareness concerning the conservation and management of the reservoir in the future.
    Matched MeSH terms: Hydrogen-Ion Concentration
  14. Formation, modeling and validation of trihalomethanes (THM) in Malaysian drinking water: a case study in the districts of Tampin, Negeri Sembilan and Sabak Bernam, Selangor, Malaysia
    Abdullah MP, Yew CH, Ramli MS
    Water Res, 2003 Nov;37(19):4637-44.
    PMID: 14568050
    A modeling procedure that predicts trihalomethane (THM) formation from field sampling at the treatment plant and along its distribution system using Tampin district, Negeri Sembilan and Sabak Bernam district, Selangor as sources of data were studied and developed. Using Pearson method of correlation, the organic matter measured as TOC showed a positive correlation with formation of THM (r=0.380,P=0.0001 for Tampin and r=0.478,P=0.0001 for Sabak Bernam). Similar positive correlation was also obtained for pH in both districts with Tampin (r=0.362,P=0.0010) and Sabak Bernam (r=0.215,P=0.0010). Chlorine dosage was also found to have low correlation with formation of THM for the two districts with Tampin (r=0.233,P=0.0230) and Sabak Bernam (r=0.505,P=0.0001). Distance from treatment plant was found to have correlation with formation of THM for Tampin district with r=0.353 and P=0.0010. Other parameters such as turbidity, ammonia, temperature and residue chlorine were found to have no correlation with formation of THM. Linear and non-linear models were developed for these two districts. The results obtained were validated using three different sets of field data obtained from own source and district of Seremban (Pantai and Sg. Terip), Negeri Sembilan. Validation results indicated that there was significant difference in the predictive and determined values of THM when two sets of data from districts of Seremban were used with an exception of field data of Sg. Terip for non-linear model developed for district of Tampin. It was found that a non-linear model is slightly better than linear model in terms of percentage prediction errors. The models developed were site specific and the predictive capabilities in the distribution systems vary with different environmental conditions.
    Matched MeSH terms: Hydrogen-Ion Concentration
  15. Characterization of aerobic granular sludge treating high strength agro-based wastewater at different volumetric loadings
    Abdullah N, Yuzir A, Curtis TP, Yahya A, Ujang Z
    Bioresour Technol, 2013 Jan;127:181-7.
    PMID: 23131639 DOI: 10.1016/j.biortech.2012.09.047
    Understanding the relationship between microbial community and mechanism of aerobic granulation could enable wider applications of granules for high-strength wastewater treatment. The majority of granulation studies principally determine the engineering aspects of granules formation with little emphasis on the microbial diversity. In this study, three identical reactors namely R1, R2 and R3 were operated using POME at volumetric loadings of 1.5, 2.5 and 3.5 kg COD m(-3) d(-1), respectively. Aeration was provided at a volumetric flow rate of 2.5 cms(-1). Aerobic granules were successfully developed in R2 and R3 while bioflocs dominated R1 until the end of experiments. Fractal dimension (D(f)) averaged at 1.90 suggesting good compactness of granules. The PCR-DGGE results indicated microbial evolutionary shift throughout granulation despite different operating OLRs based on decreased Raup and Crick similarity indices upon mature granule formation. The characteristics of aerobic granules treating high strength agro-based wastewater are determined at different volumetric loadings.
    Matched MeSH terms: Hydrogen-Ion Concentration
  16. Hydrous ferric oxide nanoparticles hosted porous polyethersulfone adsorptive membrane: chromium (VI) adsorptive studies and its applicability for water/wastewater treatment
    Abdullah N, Yusof N, Abu Shah MH, Wan Ikhsan SN, Ng ZC, Maji S, et al.
    Environ Sci Pollut Res Int, 2019 Jul;26(20):20386-20399.
    PMID: 31102226 DOI: 10.1007/s11356-019-05208-9
    In this present study, adsorptive membranes for Cr(VI) ion removal were prepared by blending polyethersulfone (PES) with hydrous ferric oxide (HFO) nanoparticles (NPs). The effects of HFO NPs to PES weight ratio (0-1.5) on the physicochemical properties of the resultant HFO/PES adsorptive membranes were investigated with respect to the surface chemistry and roughness as well as structural morphologies using different analytical instruments. The adsorptive performance of the HFO NPs/PES membranes was studied via batch adsorption experiments under various conditions by varying solution pH, initial concentration of Cr(VI), and contact time. The results showed that the membrane made of HFO/PES at a weight ratio of 1.0 exhibited the highest adsorption capacity which is 13.5 mg/g. Isotherm and kinetic studies revealed that the mechanism is best fitted to the Langmuir model and pseudo-second-order model. For filtration of Cr(VI), the best promising membranes showed improved water flux (629.3 L/m2 h) with Cr(VI) ion removal of 75%. More importantly, the newly developed membrane maintained the Cr(VI) concentration below the maximum contamination level (MCL) for up to 9 h.
    Matched MeSH terms: Hydrogen-Ion Concentration
  17. Porphyromonas gingivalis peptidylarginine deiminase substrate specificity
    Abdullah SN, Farmer EA, Spargo L, Logan R, Gully N
    Anaerobe, 2013 Oct;23:102-8.
    PMID: 23856045 DOI: 10.1016/j.anaerobe.2013.07.001
    While a group of oral commensals have been implicated in the aetiology of chronic periodontitis; the asaccharolytic Gram negative anaerobe Porphyromonas gingivalis is most commonly reported to be associated with severe forms of the disease. Although a variety of human tissues can produce a number of peptidylarginine deiminase (PAD), enzymes that convert peptide bound arginine residues to citrulline, P. gingivalis is one of the few prokaryotes known to express PAD. Protein and peptide citrullination are important in the development of rheumatoid arthritis and in recent years a number of authors have suggested a possible link between periodontitis and rheumatoid arthritis (RA). Indeed, some have linked P. gingivalis directly to RA via the action of PAD. Accordingly, the prime purpose of this study was to further characterise PAD in P. gingivalis cells particular emphasis on substrate specificity, using arginine containing peptides and RA relevant proteins.
    Matched MeSH terms: Hydrogen-Ion Concentration
  18. Fulltext Optimisation of the Photonic Efficiency of TiO2 Decorated on MWCNTs for Methylene Blue Photodegradation
    Abdullahi N, Saion E, Shaari AH, Al-Hada NM, Keiteb A
    PLoS One, 2015;10(5):e0125511.
    PMID: 25993127 DOI: 10.1371/journal.pone.0125511
    MWCNTs/TiO2 nanocomposite was prepared by oxidising MWCNT in H2SO4/HNO3 then decorating it with TiO2-p25 nanopowder. The composites were characterised using XRD, TEM, FT-IR PL and UV-vis spectroscopy. The TEM images have shown TiO2 nanoparticles immobilised onto the sidewalls of the MWCNTs. The UV-vis spectrum confirms that the nanocomposites can significantly absorb more light in the visible regions compared with the commercial TiO2 (P25). The catalytic activity of these nanocomposites was determined by photooxidation of MB aqueous solution in the presence of visible light. The MWCNTs/TiO2 (1:3) mass ratio showed maximum degradation efficiency. However, its activity was more favourable in alkaline and a neutral pH than an acidic medium.
    Matched MeSH terms: Hydrogen-Ion Concentration
  19. Fulltext Decolorization of Palm Oil Mill Effluent by Klebsiella Pneumonia ABZ11: Remediation Efficacy and Statistical Optimization of Treatment Conditions
    Abdulsalam M, Man HC, Abidin ZZ, Yunos KF, Idris AI
    Front Microbiol, 2020;11:675.
    PMID: 32477278 DOI: 10.3389/fmicb.2020.00675
    Colorants contained in palm oil mill effluent (POME) are recalcitrant and carcinogenic in nature. The commonly applied ponding treatment methods have been reported inefficient for remediating the concentration of the colorants before discharge. The need for sustainable and efficient treatment technique is crucial in order to preserve the environment. In this view, this study reported the first attempt to decolorize POME using a proliferate Klebsiella Pneumonia ABZ11 at varied inoculum sizes of 5-25% (v/v), initial color concentration (650-2,600 ADMI) and treatment time of 5-40 h. The treatment conditions were optimized using Response Surface Methodology. At optimal conditions of 20% (v/v) inoculum size, initial-color concentration of 2,600 ADMI, initial pH of 7 and 35 h treatment retention time, over 80.40% color removal was achieved with insignificant disparity compared with the model predicted value of 81.538%. Also, the Monod model excellently described the decolorization kinetic process with 0.9214 coefficient of correlation (R2), and the calculated maximum growth μ
    max
    ) and half-saturation constant (K
    s
    ) were 7.023 d-1 and 340.569 ADMI d-1, respectively. This study revealed that the Klebsiella Pneumonia ABZ11 was highly prolific and such feature may favor a synergistic biodegradation process.
    Matched MeSH terms: Hydrogen-Ion Concentration
  20. Isolation and characterization of pepsin-solubilized collagen from the integument of sea cucumber (Stichopus vastus)
    Abedin MZ, Karim AA, Ahmed F, Latiff AA, Gan CY, Che Ghazali F, et al.
    J Sci Food Agric, 2013 Mar 30;93(5):1083-8.
    PMID: 22936269 DOI: 10.1002/jsfa.5854
    Sea cucumber (Stichopus vastus) is considered an underutilized resource, since only its stomach and intestines are eaten raw as salad in a few countries and the remaining parts, especially the integument rich in collagen, is discarded. Hence a valuable by-product having potential nutraceutical and pharmaceutical applications is wasted. In the present investigation, pepsin-solubilized collagen (PSC) from the integument of S. vastus was isolated, purified and characterized.
    Matched MeSH terms: Hydrogen-Ion Concentration
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