Displaying publications 21 - 40 of 209 in total

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  1. Bioelectricity generation in microbial fuel cell using natural microflora and isolated pure culture bacteria from anaerobic palm oil mill effluent sludge
    Nor MH, Mubarak MF, Elmi HSh, Ibrahim N, Wahab MF, Ibrahim Z
    Bioresour Technol, 2015 Aug;190:458-65.
    PMID: 25799955 DOI: 10.1016/j.biortech.2015.02.103
    A double-chambered membrane microbial fuel cell (MFC) was constructed to investigate the potential use of natural microflora anaerobic palm oil mill effluent (POME) sludge and pure culture bacteria isolated from anaerobic POME sludge as inoculum for electricity generation. Sterilized final discharge POME was used as the substrate with no addition of nutrients. MFC operation using natural microflora anaerobic POME sludge showed a maximum power density and current density of 85.11mW/m(2) and 91.12mA/m(2) respectively. Bacterial identification using 16S rRNA analysis of the pure culture isolated from the biofilm on the anode MFC was identified as Pseudomonas aeruginosa strain ZH1. The electricity generated in MFC using P. aeruginosa strain ZH1 showed maximum power density and current density of 451.26mW/m(2) and 654.90mA/m(2) respectively which were five times higher in power density and seven times higher in current density compared to that of MFC using anaerobic POME sludge.
  2. Fulltext Biohydrogen Production by Antarctic Psychrotolerant Klebsiella sp. ABZ11
    Mohammed A, Abdul-Wahab MF, Hashim M, Omar AH, Md Reba MN, Muhamad Said MF, et al.
    Pol J Microbiol, 2018 11 20;67(3):283-290.
    PMID: 30451444 DOI: 10.21307/pjm-2018-033
    Lower temperature biohydrogen production has always been attractive, due to the lower energy requirements. However, the slow metabolic rate of psychrotolerant biohydrogen-producing bacteria is a common problem that affects their biohydrogen yield. This study reports on the improved substrate synthesis and biohydrogen productivity by the psychrotolerant Klebsiella sp. strain ABZ11, isolated from Antarctic seawater sample. The isolate was screened for biohydrogen production at 30°C, under facultative anaerobic condition. The isolate is able to ferment glucose, fructose and sucrose with biohydrogen production rate and yield of 0.8 mol/l/h and 3.8 mol/g, respectively at 10 g/l glucose concentration. It also showed 74% carbohydrate uptake and 95% oxygen uptake ability, and a wide growth temperature range with optimum at 37°C. Klebsiella sp. ABZ11 has a short biohydrogen production lag phase, fast substrate uptake and is able to tolerate the presence of oxygen in the culture medium. Thus, the isolate has a potential to be used for lower temperature biohydrogen production process.
  3. Fulltext Bioremediation of high-strength agricultural wastewater using Ochrobactrum sp. strain SZ1
    Neoh CH, Lam CY, Ghani SM, Ware I, Sarip SH, Ibrahim Z
    3 Biotech, 2016 Dec;6(2):143.
    PMID: 28330215 DOI: 10.1007/s13205-016-0455-1
    The biggest agricultural sector that contributes to the Malaysian economy is the oil palm industry. The effluent generated during the production of crude palm oil known as palm oil mill effluent (POME). POME undergoes anaerobic treatment that requires long retention time and produces large amount of methane that consequently contributes to global warming. In this study, an isolated bacteria was selected based on its ability to degrade kraft lignin (KL) and identified as Ochrobactrum sp. The bacteria were able to treat POME (from anaerobic pond) under the aerobic condition without addition of nutrient, resulting in a significant chemical oxygen demand (COD) removal of 71 %, removal rate of 1385 mg/l/day, and 12.3 times higher than that of the ponding system. It has also resulted in 60 % removal of ammoniacal nitrogen and 55 % of total polyphenolic after 6-day treatment period with the detection of lignocellulolytic enzymes.
  4. Biosorption and biodegradation of Acid Orange 7 by Enterococcus faecalis strain ZL: optimization by response surface methodological approach
    Lim CK, Bay HH, Aris A, Abdul Majid Z, Ibrahim Z
    Environ Sci Pollut Res Int, 2013 Jul;20(7):5056-66.
    PMID: 23334551 DOI: 10.1007/s11356-013-1476-5
    Reactive dyes account for one of the major sources of dye wastes in textile effluent. In this study, decolorization of the monoazo dye, Acid Orange 7 (AO7) by the Enterococcus faecalis strain ZL that isolated from a palm oil mill effluent treatment plant has been investigated. Decolorization efficiency of azo dye is greatly affected by the types of nutrients and the size of inoculum used. In this work, one-factor-at-a-time (method and response surface methodology (RSM) was applied to optimize these operational factors and also to study the combined interaction between them. Analysis of AO7 decolorization was done using Fourier transform infrared (FTIR) spectroscopy, desorption study, UV-Vis spectral analysis, field emission scanning electron microscopy (FESEM), and high performance liquid chromatography (HPLC). The optimum condition via RSM for the color removal of AO7 was found to be as follows: yeast extract, 0.1% w/v, glycerol concentration of 0.1% v/v, and inoculum density of 2.5% v/v at initial dye concentration of 100 mg/L at 37 °C. Decolorization efficiency of 98% was achieved in only 5 h. The kinetic of AO7 decolorization was found to be first order with respect to dye concentration with a k value of 0.87/h. FTIR, desorption study, UV-Vis spectral analysis, FESEM, and HPLC findings indicated that the decolorization of AO7 was mainly due to the biosorption as well as biodegradation of the bacterial cells. In addition, HPLC analyses also showed the formation of sulfanilic acid as a possible degradation product of AO7 under facultative anaerobic condition. This study explored the ability of E. faecalis strain ZL in decolorizing AO7 by biosorption as well as biodegradation process.
  5. Biosorption of As (III) by non-living biomass of an arsenic-hypertolerant Bacillus cereus strain SZ2 isolated from a gold mining environment: equilibrium and kinetic study
    Mohd Bahari Z, Ali Hamood Altowayti W, Ibrahim Z, Jaafar J, Shahir S
    Appl Biochem Biotechnol, 2013 Dec;171(8):2247-61.
    PMID: 24037600 DOI: 10.1007/s12010-013-0490-x
    The ability of non-living biomass of an arsenic-hypertolerant Bacillus cereus strain SZ2 isolated from a gold mining environment to adsorb As (III) from aqueous solution in batch experiments was investigated as a function of contact time, initial As (III) concentration, pH, temperature and biomass dosage. Langmuir model fitted the equilibrium data better in comparison to Freundlich isotherm. The maximum biosorption capacity of the sorbent, as obtained from the Langmuir isotherm, was 153.41 mg/g. The sorption kinetic of As (III) biosorption followed well the pseudo-second-order rate equation. The Fourier transform infrared spectroscopy analysis indicated the involvement of hydroxyl, amide and amine groups in As (III) biosorption process. Field emission scanning electron microscopy-energy dispersive X-ray analysis of the non-living B. cereus SZ2 biomass demonstrated distinct cell morphological changes with significant amounts of As adsorbed onto the cells compared to non-treated cells. Desorption of 94 % As (III) was achieved at acidic pH 1 showing the capability of non-living biomass B. cereus SZ2 as potential biosorbent in removal of As (III) from arsenic-contaminated mining effluent.
  6. Characterisation of microbial flocs formed from raw textile wastewater in aerobic biofilm reactor (ABR)
    Ibrahim Z, Amin MF, Yahya A, Aris A, Umor NA, Muda K, et al.
    Water Sci Technol, 2009;60(3):683-8.
    PMID: 19657163 DOI: 10.2166/wst.2009.440
    Microbial flocs formed from raw textile wastewater in a prototype Aerobic Biofilm Reactor (ABR) system were characterised and studied for their potential use in the treatment of textile wastewater. After 90-100 days of operation, microbial flocs of loose irregular structures were obtained from the reactor with good settling velocity of 33 m/h and sludge volume index (SVI) of 48.2 mL/g. Molecular analysis of the flocs using PCR-amplified 16S rDNA sequence showed 98% homology to those of Bacillus sp, Paenibacillus sp and Acromobacter sp. Detection of Ca(2+)(131 mg/g) and Fe(2+)(131 mg/g) using atomic absorption spectrometer might be implicated with the flocs formation. In addition, presence of Co(2+) and Ni(2+) were indicative of the flocs ability to accumulate at least a fraction of the metals' present in the wastewater. When the flocs were used for the treatment of raw textile wastewater, they showed good removal of COD and colour about 55% and 70% respectively, indicating their potential application.
  7. Characteristics of developed granules containing selected decolourising bacteria for the degradation of textile wastewater
    Ibrahim Z, Amin MF, Yahya A, Aris A, Muda K
    Water Sci Technol, 2010;61(5):1279-88.
    PMID: 20220250 DOI: 10.2166/wst.2010.021
    Textile wastewater, one of the most polluted industrial effluents, generally contains substantial amount of dyes and chemicals that will cause increase in the COD, colour and toxicity of receiving water bodies if not properly treated. Current treatment methods include chemical and biological processes; the efficiency of the biological treatment method however, remains uncertain since the discharged effluent is still highly coloured. In this study, granules consisting mixed culture of decolourising bacteria were developed and the physical and morphological characteristics were determined. After the sixth week of development, the granules were 3-10 mm in diameter, having good settling property with settling velocity of 70 m/h, sludge volume index (SVI) of 90 to 130 mL/g, integrity coefficient of 3.7, and density of 66 g/l. Their abilities to treat sterilised raw textile wastewater were evaluated based on the removal efficiencies of COD (initial ranging from 200 to 3,000 mg/L), colour (initial ranging from 450 to 2000 ADMI) of sterilised raw textile wastewater with pH from 6.8 to 9.4. Using a sequential anaerobic-aerobic treatment cycle with hydraulic retention time (HRT) of 24 h, maximum removal of colour and COD achieved was 90% and 80%, respectively.
  8. Characterization of aluminum resistant Anoxybacillus sp. SK 3-4 isolated from a hot spring
    Lim JC, Goh KM, Shamsir MS, Ibrahim Z, Chong CS
    J Basic Microbiol, 2015 Apr;55(4):514-9.
    PMID: 25523650 DOI: 10.1002/jobm.201400621
    The Anoxybacillus sp. SK 3-4, previously isolated from a hot spring, was screened for its heavy metals resistance (Al(3+), Mn(2+), Cu(2+), Co(2+), Zn(2+), and Ni(2+)) and the strain was found to be most resistant to aluminum. Significant growth of the strain was observed when it was grown in medium containing aluminum (200 mg L(-1)-800 mg L(-1)) with relative growth rates ranging between 77% and 100%. A gene encoding the aluminum resistance protein (accession number: WP_021095658.1) was found in genome of strain SK 3-4, which revealed high sequence identity (>95%) to its homologues from Anoxybacillus species. Sequence comparisons with two functionally characterized aluminum resistance proteins, namely G2alt and ALU1-P, showed 97% and 81% of sequence identity, respectively. Four putative metal binding sites were detected in SK 3-4 aluminum resistance protein and G2alt at same amino acid residue positions of 186, 195, 198, and 201. Strain SK 3-4 was found to be able to remove aluminum from aqueous solution. This study demonstrated that Anoxybacillus sp. SK 3-4 could be applied in the treatment of aluminum contaminated wastewater.
  9. Fulltext Characterization of α-Glucosidase Inhibitors from Clinacanthus nutans Lindau Leaves by Gas Chromatography-Mass Spectrometry-Based Metabolomics and Molecular Docking Simulation
    Murugesu S, Ibrahim Z, Ahmed QU, Nik Yusoff NI, Uzir BF, Perumal V, et al.
    Molecules, 2018 Sep 19;23(9).
    PMID: 30235889 DOI: 10.3390/molecules23092402
    BACKGROUND: Clinacanthus nutans (C. nutans) is an Acanthaceae herbal shrub traditionally consumed to treat various diseases including diabetes in Malaysia. This study was designed to evaluate the α-glucosidase inhibitory activity of C. nutans leaves extracts, and to identify the metabolites responsible for the bioactivity.

    METHODS: Crude extract obtained from the dried leaves using 80% methanolic solution was further partitioned using different polarity solvents. The resultant extracts were investigated for their α-glucosidase inhibitory potential followed by metabolites profiling using the gas chromatography tandem with mass spectrometry (GC-MS).

    RESULTS: Multivariate data analysis was developed by correlating the bioactivity, and GC-MS data generated a suitable partial least square (PLS) model resulting in 11 bioactive compounds, namely, palmitic acid, phytol, hexadecanoic acid (methyl ester), 1-monopalmitin, stigmast-5-ene, pentadecanoic acid, heptadecanoic acid, 1-linolenoylglycerol, glycerol monostearate, alpha-tocospiro B, and stigmasterol. In-silico study via molecular docking was carried out using the crystal structure Saccharomyces cerevisiae isomaltase (PDB code: 3A4A). Interactions between the inhibitors and the protein were predicted involving residues, namely LYS156, THR310, PRO312, LEU313, GLU411, and ASN415 with hydrogen bond, while PHE314 and ARG315 with hydrophobic bonding.

    CONCLUSION: The study provides informative data on the potential α-glucosidase inhibitors identified in C. nutans leaves, indicating the plant's therapeutic effect to manage hyperglycemia.

  10. Fulltext Characterization of α-Glucosidase Inhibitors from Psychotria malayana Jack Leaves Extract Using LC-MS-Based Multivariate Data Analysis and In-Silico Molecular Docking
    Nipun TS, Khatib A, Ibrahim Z, Ahmed QU, Redzwan IE, Saiman MZ, et al.
    Molecules, 2020 Dec 12;25(24).
    PMID: 33322801 DOI: 10.3390/molecules25245885
    Psychotria malayana Jack has traditionally been used to treat diabetes. Despite its potential, the scientific proof in relation to this plant is still lacking. Thus, the present study aimed to investigate the α-glucosidase inhibitors in P.malayana leaf extracts using a metabolomics approach and to elucidate the ligand-protein interactions through in silico techniques. The plant leaves were extracted with methanol and water at five various ratios (100, 75, 50, 25 and 0% v/v; water-methanol). Each extract was tested for α-glucosidase inhibition, followed by analysis using liquid chromatography tandem to mass spectrometry. The data were further subjected to multivariate data analysis by means of an orthogonal partial least square in order to correlate the chemical profile and the bioactivity. The loading plots revealed that the m/z signals correspond to the activity of α-glucosidase inhibitors, which led to the identification of three putative bioactive compounds, namely 5'-hydroxymethyl-1'-(1, 2, 3, 9-tetrahydro-pyrrolo (2, 1-b) quinazolin-1-yl)-heptan-1'-one (1), α-terpinyl-β-glucoside (2), and machaeridiol-A (3). Molecular docking of the identified inhibitors was performed using Auto Dock Vina software against the crystal structure of Saccharomyces cerevisiae isomaltase (Protein Data Bank code: 3A4A). Four hydrogen bonds were detected in the docked complex, involving several residues, namely ASP352, ARG213, ARG442, GLU277, GLN279, HIE280, and GLU411. Compound 1, 2, and 3 showed binding affinity values of -8.3, -7.6, and -10.0 kcal/mol, respectively, which indicate the good binding ability of the compounds towards the enzyme when compared to that of quercetin, a known α-glucosidase inhibitor. The three identified compounds that showed potential binding affinity towards the enzymatic protein in molecular docking interactions could be the bioactive compounds associated with the traditional use of this plant.
  11. Clinical malnutrition predictive model among gynecologic cancer patients prior to elective operation: A cross-sectional study
    Ho CY, Ibrahim Z, Abu Zaid Z, Mat Daud Z', Md Yusop NB
    Clin Nutr, 2021 06;40(6):4373-4379.
    PMID: 33485706 DOI: 10.1016/j.clnu.2021.01.008
    BACKGROUND: Malnutrition is common among cancer patients regardless of stage of cancer. Given the strong association between malnutrition with prolonged hospitalization, delayed recovery and even higher post-operative complications among gynaecologic cancer (GC) patients, it is important to understand its predictive factors. The current study aimed to determine malnutrition predictors among GC patients before elective operation.

    METHOD: A cross-sectional study was conducted among surgical GC patients who were admitted for elective surgery. Data on socio-demographic characteristics, clinical status (diagnosis, the staging of cancer, comorbidities and family history on cancer), anthropometric measures [ Body Mass Index (BMI), weight changes, the percentage of weight loss past one month, muscle mass, fat mass, fat-free mass and mid-upper arm circumference (MUAC)], biochemical profiles [C-reactive protein, albumin and C-reactive protein (CRP) to albumin ratio (CAR)], handgrip strength, total daily energy and protein intake, and malnutrition status [scored Patient Generated-Subjective Global Assessment (PG-SGA)] were assessed during admission.

    RESULTS: Study recruited 124 participants and 57.2% (n = 71) were malnourished. Mean for age, weight changes past one month, handgrip strength, total daily energy and protein intake, PG-SGA score and CAR of participants were 49.9 ± 12.5 years, -4.9 ± 7.2%, 15.6 ± 6.2 kg, 25±7 kcal/kg/day, 1.0 ± 0.3 g/kg/day, 6.5 ± 5.4 and 0.7 ± 1.9, respectively. Multiple linear regression test revealed that the percentage of weight loss past one month, haemoglobin, CRP and handgrip strength were the significant predictors of malnutrition.

    CONCLUSION: Malnutrition is common among GC patient even before elective operation. The early malnutrition screening following with proper nutritional intervention is crucial to optimize nutritional status among GC patients before elective operation.

  12. Combination of Searches for Higgs Boson Pair Production in Proton-Proton Collisions at sqrt[s]=13  TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2019 Mar 29;122(12):121803.
    PMID: 30978057 DOI: 10.1103/PhysRevLett.122.121803
    This Letter describes a search for Higgs boson pair production using the combined results from four final states: bbγγ, bbττ, bbbb, and bbVV, where V represents a W or Z boson. The search is performed using data collected in 2016 by the CMS experiment from LHC proton-proton collisions at sqrt[s]=13  TeV, corresponding to an integrated luminosity of 35.9  fb^{-1}. Limits are set on the Higgs boson pair production cross section. A 95% confidence level observed (expected) upper limit on the nonresonant production cross section is set at 22.2 (12.8) times the standard model value. A search for narrow resonances decaying to Higgs boson pairs is also performed in the mass range 250-3000 GeV. No evidence for a signal is observed, and upper limits are set on the resonance production cross section.
  13. Fulltext Combined measurements of Higgs boson couplings in proton-proton collisions at s = 13 Te
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Eur Phys J C Part Fields, 2019;79(5):421.
    PMID: 31178657 DOI: 10.1140/epjc/s10052-019-6909-y
    Combined measurements of the production and decay rates of the Higgs boson, as well as its couplings to vector bosons and fermions, are presented. The analysis uses the LHC proton-proton collision data set recorded with the CMS detector in 2016 at s = 13 Te , corresponding to an integrated luminosity of 35.9 fb - 1 . The combination is based on analyses targeting the five main Higgs boson production mechanisms (gluon fusion, vector boson fusion, and associated production with a W or Z boson, or a top quark-antiquark pair) and the following decay modes: H → γ γ , Z Z , W W , τ τ , b b , and μ μ . Searches for invisible Higgs boson decays are also considered. The best-fit ratio of the signal yield to the standard model expectation is measured to be μ = 1.17 ± 0.10 , assuming a Higgs boson mass of 125.09 Ge . Additional results are given for various assumptions on the scaling behavior of the production and decay modes, including generic parametrizations based on ratios of cross sections and branching fractions or couplings. The results are compatible with the standard model predictions in all parametrizations considered. In addition, constraints are placed on various two Higgs doublet models.
  14. Comparative Assessment of a Self-sampling Device and Gynecologist Sampling for Cytology and HPV DNA Detection in a Rural and Low Resource Setting: Malaysian Experience
    Latiff LA, Ibrahim Z, Pei CP, Rahman SA, Akhtari-Zavare M
    Asian Pac J Cancer Prev, 2015;16(18):8495-501.
    PMID: 26745108
    PURPOSE: This study was conducted to assess the agreement and differences between cervical self-sampling with a Kato device (KSSD) and gynecologist sampling for Pap cytology and human papillomavirus DNA (HPV DNA) detection.

    MATERIALS AND METHODS: Women underwent self-sampling followed by gynecologist sampling during screening at two primary health clinics. Pap cytology of cervical specimens was evaluated for specimen adequacy, presence of endocervical cells or transformation zone cells and cytological interpretation for cells abnormalities. Cervical specimens were also extracted and tested for HPV DNA detection. Positive HPV smears underwent gene sequencing and HPV genotyping by referring to the online NCBI gene bank. Results were compared between samplings by Kappa agreement and McNemar test.

    RESULTS: For Pap specimen adequacy, KSSD showed 100% agreement with gynecologist sampling but had only 32.3% agreement for presence of endocervical cells. Both sampling showed 100% agreement with only 1 case detected HSIL favouring CIN2 for cytology result. HPV DNA detection showed 86.2%agreement (K=0.64, 95% CI 0.524-0.756, p=0.001) between samplings. KSSD and gynaecologist sampling identified high risk HPV in 17.3% and 23.9% respectively (p= 0.014).

    CONCLUSION: The self-sampling using Kato device can serve as a tool in Pap cytology and HPV DNA detection in low resource settings in Malaysia. Self-sampling devices such as KSSD can be used as an alternative technique to gynaecologist sampling for cervical cancer screening among rural populations in Malaysia.

  15. Comparison of Isolation, Expansion and Cryopreservation Techniques to Produce Stem Cells from Human Exfoliated Deciduous Teeth (SHED) with Better Regenerative Potential
    Lee SH, Looi CY, Chong PP, Foo JB, Looi QH, Ng CX, et al.
    Curr Stem Cell Res Ther, 2021;16(5):551-562.
    PMID: 32988356 DOI: 10.2174/1574888X15666200928110923
    Mesenchymal Stem Cells (MSCs) are adult stem cells that are gaining worldwide attention for their multi-potential use in tissue engineering-based regenerative medicine. They can be obtained from numerous sources and one of the excellent sources is the dental tissue, such as Stem cells that are extracted from the Human Exfoliated Deciduous teeth (SHED). SHED are considered ideal due to their inherent characteristics, including the capability to proliferate quickly with minimal oncogenesis risk, multipotency capacity and their ability to suppress the immune system. On top of these positive cell traits, SHED are easily accessible with the patient's safety assured, posing less ethical issues and could also provide a sufficient number of cells for prospective clinical uses. This is primarily attributed to their ability to differentiate into multiple cell linages, including osteoblasts, odontoblasts, neuronal cells, adipocytes, as well as endothelial cells. Albeit SHED having a bright future, there still remains an obstacle to develop reliable experimental techniques to retain the long-term regeneration potential of the stem cells for prospective research and clinical applications. Therefore, this review aims to describe the various isolation, expansion and cryopreservation techniques used by researchers in this stem cell field. Optimization of these techniques is crucial to obtain distinct SHED culture with preserved stem cell properties, which enable more reproducible results that will be the key for further stem cell therapy development.
  16. Fulltext Comparison of Optimization-Modelling Methods for Metabolites Production in Escherichia coli
    Lee MK, Mohamad MS, Choon YW, Mohd Daud K, Nasarudin NA, Ismail MA, et al.
    J Integr Bioinform, 2020 May 06;17(1).
    PMID: 32374287 DOI: 10.1515/jib-2019-0073
    The metabolic network is the reconstruction of the metabolic pathway of an organism that is used to represent the interaction between enzymes and metabolites in genome level. Meanwhile, metabolic engineering is a process that modifies the metabolic network of a cell to increase the production of metabolites. However, the metabolic networks are too complex that cause problem in identifying near-optimal knockout genes/reactions for maximizing the metabolite's production. Therefore, through constraint-based modelling, various metaheuristic algorithms have been improvised to optimize the desired phenotypes. In this paper, PSOMOMA was compared with CSMOMA and ABCMOMA for maximizing the production of succinic acid in E. coli. Furthermore, the results obtained from PSOMOMA were validated with results from the wet lab experiment.
  17. Constraining Gluon Distributions in Nuclei Using Dijets in Proton-Proton and Proton-Lead Collisions at sqrt[s_{NN}]=5.02  TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2018 Aug 10;121(6):062002.
    PMID: 30141647 DOI: 10.1103/PhysRevLett.121.062002
    The pseudorapidity distributions of dijets as functions of their average transverse momentum (p_{T}^{ave}) are measured in proton-lead (pPb) and proton-proton (pp) collisions. The data samples were collected by the CMS experiment at the CERN LHC, at a nucleon-nucleon center-of-mass energy of 5.02 TeV. A significant modification of the pPb spectra with respect to the pp spectra is observed in all p_{T}^{ave} intervals investigated. The ratios of the pPb and pp distributions are compared to next-to-leading order perturbative quantum chromodynamics calculations with unbound nucleon and nuclear parton distribution functions (PDFs). These results give the first evidence that the gluon PDF at large Bjorken x in lead ions is strongly suppressed with respect to the PDF in unbound nucleons.
  18. Cytotoxic xanthones isolated from Calophyllum depressinervosum and Calophyllum buxifolium with antioxidant and cytotoxic activities
    Zamakshshari NH, Ee GCL, Ismail IS, Ibrahim Z, Mah SH
    Food Chem Toxicol, 2019 Nov;133:110800.
    PMID: 31479710 DOI: 10.1016/j.fct.2019.110800
    The stem bark of Calophyllum depressinervosum and Calophyllum buxifolium were extracted and examined for their antioxidant activities, together with cytotoxicity towards human cancer cells. The methanol extract of C. depressinervosum exhibited good DPPH and NO scavenging effects. The strongest BCB inhibition and FIC effects were shown by dichloromethane and ethyl acetate extracts of both species. Overall, DPPH, FRAP and FIC assays showed strong correlation with TPC. For cytotoxicity, hexane extract of C. depressinervosum possessed the strongest anti-proliferative activities towards SNU-1 cells while the hexane extract of C. buxifolium showed the strongest activity towards LS-174T and K562 cells with the IC50 values ranging from 7 to 17 μg/mL. The purification of plant extracts afforded eight xanthones, ananixanthone (1), caloxanthone B (2), caloxanthone I (3), caloxanthone J (4) xanthochymone B (5), thwaitesixanthone (6), 1,3,5,6-tetrahydroxyxanthone (7) and dombakinaxanthone (8). All the xanthones, except 1 were reported for the first time from both Calophyllum species. The xanthones were examined for their cytotoxic effect against K562 leukemic cells. Compounds 1 and 2 showed strong cytotoxicity with the IC50 values of 2.96 and 1.23 μg/mL, respectively. The molecular binding interaction of 2 was further investigated by performing molecular docking study with promising protein receptor Src kinase.
  19. Decolorization of palm oil mill effluent using growing cultures of Curvularia clavata
    Neoh CH, Lam CY, Lim CK, Yahya A, Ibrahim Z
    Environ Sci Pollut Res Int, 2014 Mar;21(6):4397-408.
    PMID: 24327114 DOI: 10.1007/s11356-013-2350-1
    Agricultural wastewater that produces color are of environmental and health concern as colored effluent can produce toxic and carcinogenic by-products. From this study, batch culture optimization using response surface methods indicated that the fungus isolated from the pineapple solid waste, Curvularia clavata was able to decolorize sterile palm oil mill effluent (POME) which is mainly associated with polyphenol and lignin. Results showed successful decolorization of POME up to 80 % (initial ADMI [American Dye Manufacturing Index] of 3,793) with 54 % contributed by biosorption and 46 % by biodegradation after 5 days of treatment. Analysis using HPLC and GC-MS showed the degradation of color causing compound such as 3-methoxyphenyl isothiocynate and the production of new metabolites. Ecotoxicity test indicated that the decolorized effluent is safe for discharge. To determine the longevity of the fungus for a prolonged decolorization period, sequential batch decolorization studies were carried out. The results showed that lignin peroxidase and laccase were the main ligninolytic enzymes involved in the degradation of color. Carboxymethyl cellulase (CMCase) and xylanase activities were also detected suggesting possible roles of the enzymes in promoting growth of the fungus which consequently contributed to improved decolorization of POME. In conclusion, the ability of C. clavata in treating color of POME indicated that C. clavata is of potential use for decolorization and degradation of agricultural wastewater containing polyphenolic compounds.
  20. Decolourisation of Acid Orange 7 recalcitrant auto-oxidation coloured by-products using an acclimatised mixed bacterial culture
    Bay HH, Lim CK, Kee TC, Ware I, Chan GF, Shahir S, et al.
    Environ Sci Pollut Res Int, 2014 Mar;21(5):3891-906.
    PMID: 24293297 DOI: 10.1007/s11356-013-2331-4
    This study focuses on the biodegradation of recalcitrant, coloured compounds resulting from auto-oxidation of Acid Orange 7 (AO7) in a sequential facultative anaerobic-aerobic treatment system. A novel mixed bacterial culture, BAC-ZS, consisting of Brevibacillus panacihumi strain ZB1, Lysinibacillus fusiformis strain ZB2, and Enterococcus faecalis strain ZL bacteria were isolated from environmental samples. The acclimatisation of the mixed culture was carried out in an AO7 decolourised solution. The acclimatised mixed culture showed 98 % decolourisation within 2 h of facultative anaerobic treatment using yeast extract and glucose as co-substrate. Subsequent aerobic post treatment caused auto-oxidation reaction forming dark coloured compounds that reduced the percentage decolourisation to 73 %. Interestingly, further agitations of the mixed culture in the solution over a period of 48 h significantly decolourise the coloured compounds and increased the decolourisation percentage to 90 %. Analyses of the degradation compounds using UV-visible spectrophotometer, Fourier transform infrared spectroscopy (FTIR) and high performance liquid chromatography (HPLC) showed complete degradation of recalcitrant AO7 by the novel BAC-ZS. Phytotoxicity tests using Cucumis sativus confirmed the dye solution after post aerobic treatment were less toxic compared to the parent dye. The quantitative real-time PCR revealed that E. faecalis strain ZL was the dominant strain in the acclimatised mix culture.
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