Displaying publications 1 - 20 of 28 in total

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  1. Synthesis of new indazole based dual inhibitors of α-glucosidase and α-amylase enzymes, their in vitro, in silico and kinetics studies
    Rafique R, Khan KM, Arshia, Kanwal, Chigurupati S, Wadood A, et al.
    Bioorg Chem, 2020 01;94:103195.
    PMID: 31451297 DOI: 10.1016/j.bioorg.2019.103195
    The current study describes the discovery of novel inhibitors of α-glucosidase and α-amylase enzymes. For that purpose, new hybrid analogs of N-hydrazinecarbothioamide substituted indazoles 4-18 were synthesized and fully characterized by EI-MS, FAB-MS, HRFAB-MS, 1H-, and 13C NMR spectroscopic techniques. Stereochemistry of the imine double bond was established by NOESY measurements. All derivatives 4-18 with their intermediates 1-3, were evaluated for in vitro α-glucosidase and α-amylase enzyme inhibition. It is worth mentioning that all synthetic compounds showed good inhibition potential in the range of 1.54 ± 0.02-4.89 ± 0.02 µM for α-glucosidase and for α-amylase 1.42 ± 0.04-4.5 ± 0.18 µM in comparison with the standard acarbose (IC50 value of 1.36 ± 0.01 µM). In silico studies were carried out to rationalize the mode of binding interaction of ligands with the active site of enzymes. Moreover, enzyme inhibitory kinetic characterization was also performed to understand the mechanism of enzyme inhibition.
    Matched MeSH terms: Carbon Isotopes
  2. Fulltext Olecranon Osteotomy Approach for Complex AO-13C Fractures of Distal Humerus: A Prospective Analysis of 24 Cases
    Singh R, Singh H, Kanodia N
    Malays Orthop J, 2019 Mar;13(1):30-35.
    PMID: 31001381 DOI: 10.5704/MOJ.1903.005
    Introduction: Olecranon osteotomy is well described approach for complex intra-articular distal humeral fractures. In this study, we investigated the usefulness and complications of olecranon osteotomy approach for such fractures. We hypothesise that outcome is comparable in young adults and middle age group and also functional outcome is independent of fracture subtype following surgical fixation. Materials and Methods: Between December 2012 and September 2015, twenty-four adult patients (male: 15, female: 9) having mean age of 41.4 years with closed intra-articular fracture (AO-13C) were surgically managed using olecranon osteotomy approach and were followed-up for a mean of 28.5 months (range: 22-35 months). Functional outcome was measured using Mayo Elbow Performance Score (MEPS) and complications were observed. Statistical analysis was done using Student t-test and Kruskal Wallis test. Results: All fractures united by the end of three months. Mean elbow flexion achieved was 123°, mean extension lag was 9° and mean active arc of motion was 114°. Mean MEPS was 87 (excellent: 8, good: 14, fair: 1 and poor: 1). Post-operative transient ulnar nerve palsy was noted in two cases, heterotopic ossification (HO) was in one case, infection in two cases, implant prominence in five and elbow stiffness in three cases. Motion arc was higher in young adults and MEPS was comparable in both age group. Functional outcome was also dependent on fracture subtype. Conclusion: The olecranon osteotomy approach for distal humerus fractures had good functional outcome with fewer complications. Joint congruity and fixation could easily be assessed intraoperatively.
    Matched MeSH terms: Carbon Isotopes
  3. Acetate and glucose utilisation and lipid synthesis by cold-acclimated and hypothermic rat-brain homogenates
    Perumal R, Bhattathiry EP
    Med J Malaya, 1970 Mar;24(3):208-11.
    PMID: 4246803
    Matched MeSH terms: Carbon Isotopes
  4. Green synthesis of selenium-N-heterocyclic carbene compounds: Evaluation of antimicrobial and anticancer potential
    Kamal A, Nazari V M, Yaseen M, Iqbal MA, Ahamed MBK, Majid ASA, et al.
    Bioorg Chem, 2019 09;90:103042.
    PMID: 31226469 DOI: 10.1016/j.bioorg.2019.103042
    Three benzimidazolium salts (III-V) and respective selenium adducts (VI-VIII) were designed, synthesized and characterized by various analytical techniques (FT-IR and NMR 1H, 13C). Selected salts and respective selenium N-Heterocyclic carbenes (selenium-NHC) adducts were tested in vitro against Cervical Cancer Cell line (Hela), Breast Adenocarcinoma cell line (MCF-7), Retinal Ganglion Cell line (RGC-5) and Mouse Melanoma Cell line (B16F10) using MTT assay and the results were compared with standard drug 5-Fluorouracil. Se-NHC compounds and azolium salts showed significant anticancer potential. Molecular docking studies of compounds (VI, VII and VIII) showed strong binding energies and ligand affinity toward following angiogenic factors: VEGF-A (vascular endothelial growth factor A), EGF (human epidermal growth factor), HIF (Hypoxia-inducible factor) and COX-1 (Cyclooxygenase-1) suggesting that the anticancer activity of adducts (VI, VII and VIII) may be due to their strong anti-angiogenic effect. In addition, compounds III-VIII were screened for their antibacterial and antifungal potential. Adduct VI was found to be potent anti-fungal agent against A. Niger with zone of inhibition (ZI) value 27.01 ± 0.251 mm which is better than standard drug Clotrimazole tested in parallel.
    Matched MeSH terms: Carbon Isotopes
  5. Fulltext Recent trends in the intrinsic water-use efficiency of ringless rainforest trees in Borneo
    Loader NJ, Walsh RP, Robertson I, Bidin K, Ong RC, Reynolds G, et al.
    Philos Trans R Soc Lond B Biol Sci, 2011 Nov 27;366(1582):3330-9.
    PMID: 22006972 DOI: 10.1098/rstb.2011.0037
    Stable carbon isotope (δ(13)C) series were developed from analysis of sequential radial wood increments from AD 1850 to AD 2009 for four mature primary rainforest trees from the Danum and Imbak areas of Sabah, Malaysia. The aseasonal equatorial climate meant that conventional dendrochronology was not possible as the tree species investigated do not exhibit clear annual rings or dateable growth bands. Chronology was established using radiocarbon dating to model age-growth relationships and date the carbon isotopic series from which the intrinsic water-use efficiency (IWUE) was calculated. The two Eusideroxylon zwageri trees from Imbak yielded ages of their pith/central wood (±1 sigma) of 670 ± 40 and 759 ± 40 years old; the less dense Shorea johorensis and Shorea superba trees at Danum yielded ages of 240 ± 40 and 330 ± 40 years, respectively. All trees studied exhibit an increase in the IWUE since AD 1960. This reflects, in part, a response of the forest to increasing atmospheric carbon dioxide concentration. Unlike studies of some northern European trees, no clear plateau in this response was observed. A change in the IWUE implies an associated modification of the local carbon and/or hydrological cycles. To resolve these uncertainties, a shift in emphasis away from high-resolution studies towards long, well-replicated time series is proposed to develop the environmental data essential for model evaluation. Identification of old (greater than 700 years) ringless trees demonstrates their potential in assessing the impacts of climatic and atmospheric change. It also shows the scientific and applied value of a conservation policy that ensures the survival of primary forest containing particularly old trees (as in Imbak Canyon and Danum).
    Matched MeSH terms: Carbon Isotopes/chemistry
  6. Fulltext Long-term succession in a coal seam microbiome during in situ biostimulation of coalbed-methane generation
    Beckmann S, Luk AWS, Gutierrez-Zamora ML, Chong NHH, Thomas T, Lee M, et al.
    ISME J, 2019 03;13(3):632-650.
    PMID: 30323265 DOI: 10.1038/s41396-018-0296-5
    Despite the significance of biogenic methane generation in coal beds, there has never been a systematic long-term evaluation of the ecological response to biostimulation for enhanced methanogenesis in situ. Biostimulation tests in a gas-free coal seam were analysed over 1.5 years encompassing methane production, cell abundance, planktonic and surface associated community composition and chemical parameters of the coal formation water. Evidence is presented that sulfate reducing bacteria are energy limited whilst methanogenic archaea are nutrient limited. Methane production was highest in a nutrient amended well after an oxic preincubation phase to enhance coal biofragmentation (calcium peroxide amendment). Compound-specific isotope analyses indicated the predominance of acetoclastic methanogenesis. Acetoclastic methanogenic archaea of the Methanosaeta and Methanosarcina genera increased with methane concentration. Acetate was the main precursor for methanogenesis, however more acetate was consumed than methane produced in an acetate amended well. DNA stable isotope probing showed incorporation of 13C-labelled acetate into methanogenic archaea, Geobacter species and sulfate reducing bacteria. Community characterisation of coal surfaces confirmed that methanogenic archaea make up a substantial proportion of coal associated biofilm communities. Ultimately, methane production from a gas-free subbituminous coal seam was stimulated despite high concentrations of sulfate and sulfate-reducing bacteria in the coal formation water. These findings provide a new conceptual framework for understanding the coal reservoir biosphere.
    Matched MeSH terms: Carbon Isotopes/analysis
  7. Fulltext Forest contraction in north equatorial Southeast Asia during the Last Glacial Period
    Wurster CM, Bird MI, Bull ID, Creed F, Bryant C, Dungait JA, et al.
    Proc Natl Acad Sci U S A, 2010 Aug 31;107(35):15508-11.
    PMID: 20660748 DOI: 10.1073/pnas.1005507107
    Today, insular Southeast Asia is important for both its remarkably rich biodiversity and globally significant roles in atmospheric and oceanic circulation. Despite the fundamental importance of environmental history for diversity and conservation, there is little primary evidence concerning the nature of vegetation in north equatorial Southeast Asia during the Last Glacial Period (LGP). As a result, even the general distribution of vegetation during the Last Glacial Maximum is debated. Here we show, using the stable carbon isotope composition of ancient cave guano profiles, that there was a substantial forest contraction during the LGP on both peninsular Malaysia and Palawan, while rainforest was maintained in northern Borneo. These results directly support rainforest "refugia" hypotheses and provide evidence that environmental barriers likely reduced genetic mixing between Borneo and Sumatra flora and fauna. Moreover, it sheds light on possible early human dispersal events.
    Matched MeSH terms: Carbon Isotopes/metabolism
  8. Fulltext Experimental and DFT data of p-chlorocalix[4]arene as drugs receptor
    Kadir MA, Abdul Razak FI, Haris NSH
    Data Brief, 2020 Oct;32:106263.
    PMID: 32905010 DOI: 10.1016/j.dib.2020.106263
    The data in this article provide information on spectroscopic and theoretical data for p-chlorocalix[4]arene when combined with selected drugs, such as paracetamol, ibuprofen, and cetirizine. The present spectroscopic data are generated from Fourier Transform Infrared (FTIR), Nuclear Magnetic Resonance (1H NMR and 13C NMR), and Ultraviolet-Visible spectroscopy (UV-Vis) as the key tools for molecular characterization. The measurement of the optimization energy, interaction energy, and the band gap energy between the molecules was calculated by Gaussian 09 software. It is interesting to note that of the three titled drugs identified, p-chlorocalix[4]arene showed the highest interaction energy with paracetamol, followed by ibuprofen and cetirizine.
    Matched MeSH terms: Carbon Isotopes
  9. Fulltext o-Vanillin Derived Schiff Bases and Their Organotin(IV) Compounds: Synthesis, Structural Characterisation, In-Silico Studies and Cytotoxicity
    Yusof ENM, Latif MAM, Tahir MIM, Sakoff JA, Simone MI, Page AJ, et al.
    Int J Mol Sci, 2019 Feb 15;20(4).
    PMID: 30781445 DOI: 10.3390/ijms20040854
    Six new organotin(IV) compounds of Schiff bases derived from S-R-dithiocarbazate [R = benzyl (B), 2- or 4-methylbenzyl (2M and 4M, respectively)] condensed with 2-hydroxy-3-methoxybenzaldehyde (oVa) were synthesised and characterised by elemental analysis, various spectroscopic techniques including infrared, UV-vis, multinuclear (¹H, 13C, 119Sn) NMR and mass spectrometry, and single crystal X-ray diffraction. The organotin(IV) compounds were synthesised from the reaction of Ph₂SnCl₂ or Me₂SnCl₂ with the Schiff bases (S2MoVaH/S4MoVaH/SBoVaH) to form a total of six new organotin(IV) compounds that had a general formula of [R₂Sn(L)] (where L = Schiff base; R = Ph or Me). The molecular geometries of Me₂Sn(S2MoVa), Me₂Sn(S4MoVa) and Me₂Sn(SBoVa) were established by X-ray crystallography and verified using density functional theory calculations. Interestingly, each experimental structure contained two independent but chemically similar molecules in the crystallographic asymmetric unit. The coordination geometry for each molecule was defined by thiolate-sulphur, phenoxide-oxygen and imine-nitrogen atoms derived from a dinegative, tridentate dithiocarbazate ligand with the remaining positions occupied by the methyl-carbon atoms of the organo groups. In each case, the resulting five-coordinate C₂NOS geometry was almost exactly intermediate between ideal trigonal-bipyramidal and square-pyramidal geometries. The cytotoxic activities of the Schiff bases and organotin(IV) compounds were investigated against EJ-28 and RT-112 (bladder), HT29 (colon), U87 and SJ-G2 (glioblastoma), MCF-7 (breast) A2780 (ovarian), H460 (lung), A431 (skin), DU145 (prostate), BE2-C (neuroblastoma) and MIA (pancreatic) cancer cell lines and one normal breast cell line (MCF-10A). Diphenyltin(IV) compounds exhibited greater potency than either the Schiff bases or the respective dimethyltin(IV) compounds. Mechanistic studies on the action of these compounds against bladder cancer cells revealed that they induced the production of reactive oxygen species (ROS). The bladder cancer cells were apoptotic after 24 h post-treatment with the diphenyltin(IV) compounds. The interactions of the organotin(IV) compounds with calf thymus DNA (CT-DNA) were experimentally explored using UV-vis absorption spectroscopy. This study revealed that the organotin(IV) compounds have strong DNA binding affinity, verified via molecular docking simulations, which suggests that these organotin(IV) compounds interact with DNA via groove-binding interactions.
    Matched MeSH terms: Carbon Isotopes
  10. Fulltext Synthesis, enzyme inhibitory kinetics mechanism and computational study of N-(4-methoxyphenethyl)-N-(substituted)-4-methylbenzenesulfonamides as novel therapeutic agents for Alzheimer's disease
    Abbasi MA, Hassan M, Aziz-Ur-Rehman, Siddiqui SZ, Shah SAA, Raza H, et al.
    PeerJ, 2018;6:e4962.
    PMID: 29967717 DOI: 10.7717/peerj.4962
    The present study comprises the synthesis of a new series of sulfonamides derived from 4-methoxyphenethylamine (1). The synthesis was initiated by the reaction of 1 with 4-methylbenzenesulfonyl chloride (2) in aqueous sodium carbonate solution at pH 9 to yield N-(4-methoxyphenethyl)-4-methylbenzensulfonamide (3).This parent molecule 3 was subsequently treated with various alkyl/aralkyl halides, (4a-j), using N,N-dimethylformamide (DMF) as solvent and LiH as activator to produce a series of new N-(4-methoxyphenethyl)-N-(substituted)-4-methylbenzenesulfonamides (5a-j). The structural characterization of these derivatives was carried out by spectroscopic techniques like IR, 1H-NMR, and 13C-NMR. The elemental analysis data was also coherent with spectral data of these molecules. The inhibitory effects on acetylcholinesterase and DPPH were evaluated and it was observed that N-(4-Methoxyphenethyl)-4-methyl-N-(2-propyl)benzensulfonamide (5c) showed acetylcholinesterase inhibitory activity 0.075 ± 0.001 (IC50 0.075 ± 0.001 µM) comparable to Neostigmine methylsulfate (IC50 2.038 ± 0.039 µM).The docking studies of synthesized ligands 5a-j were also carried out against acetylcholinesterase (PDBID 4PQE) to compare the binding affinities with IC50 values. The kinetic mechanism analyzed by Lineweaver-Burk plots demonstrated that compound (5c) inhibits the acetylcholinesterase competitively to form an enzyme inhibitor complex. The inhibition constants Ki calculated from Dixon plots for compound (5c) is 2.5 µM. It was also found from kinetic analysis that derivative 5c irreversible enzyme inhibitor complex. It is proposed on the basis of our investigation that title compound 5c may serve as lead structure for the design of more potent acetylcholinesterase inhibitors.
    Matched MeSH terms: Carbon Isotopes
  11. Fulltext Sex and species specific isotopic niche specialisation increases with trophic complexity: evidence from an ephemeral pond ecosystem
    Dalu T, Wasserman RJ, Vink TJ, Weyl OL
    Sci Rep, 2017 02 24;7:43229.
    PMID: 28233858 DOI: 10.1038/srep43229
    It is generally accepted that organisms that naturally exploit an ecosystem facilitate coexistence, at least partially, through resource partitioning. Resource availability is, however, highly variable in space and time and as such the extent of resource partitioning must be somewhat dependent on availability. Here we test aspects of resource partitioning at the inter- and intra-specific level, in relation to resource availability in an atypical aquatic environment using an isotope approach. Using closely related key organisms from an ephemeral pond, we test for differences in isotopic signatures between two species of copepod and between sexes within each species, in relation to heterogeneity of basal food resources over the course of the ponds hydroperiod. We show that basal food resource heterogeneity increases over time initially, and then decreases towards the end of the hydroperiod, reflective of the expected evolution of trophic complexity for these systems. Resource partitioning also varied between species and sexes, over the hydroperiod with intra- and inter-specific specialisation relating to resource availability. Intra-specific specialisation was particularly evident in the omnivorous copepod species. Our findings imply that trophic specialisation at both the intra- and inter-specific level is partly driven by basal food resource availability.
    Matched MeSH terms: Carbon Isotopes
  12. Flurbiprofen derivatives as novel α-amylase inhibitors: Biology-oriented drug synthesis (BIODS), in vitro, and in silico evaluation
    Khan M, Alam A, Khan KM, Salar U, Chigurupati S, Wadood A, et al.
    Bioorg Chem, 2018 12;81:157-167.
    PMID: 30125730 DOI: 10.1016/j.bioorg.2018.07.038
    Novel derivatives of flurbiprofen 1-18 including flurbiprofen hydrazide 1, substituted aroyl hydrazides 2-9, 2-mercapto oxadiazole derivative 10, phenacyl substituted 2-mercapto oxadiazole derivatives 11-15, and benzyl substituted 2-mercapto oxadiazole derivatives 16-18 were synthesized and characterized by EI-MS, 1H and 13C NMR spectroscopic techniques. All derivatives 1-18 were screened for α-amylase inhibitory activity and demonstrated a varying degree of potential ranging from IC50 = 1.04 ± 0.3 to 2.41 ± 0.09 µM as compared to the standard acarbose (IC50 = 0.9 ± 0.04 µM). Out of eighteen compounds, derivatives 2 (IC50 = 1.69 ± 0.1 µM), 3 (IC50 = 1.04 ± 0.3 µM), 9 (IC50 = 1.25 ± 1.05 µM), and 13 (IC50 = 1.6 ± 0.18 µM) found to be excellent inhibitors while rest of the compounds demonstrated comparable inhibition potential. A limited structure-activity relationship (SAR) was established by looking at the varying structural features of the library. In addition to that, in silico study was conducted to understand the binding interactions of the compounds (ligands) with the active site of α-amylase enzyme.
    Matched MeSH terms: Carbon Isotopes
  13. Synthesis, molecular docking, dynamic simulations, kinetic mechanism, cytotoxicity evaluation of N-(substituted-phenyl)-4-{(4-[(E)-3-phenyl-2-propenyl]-1-piperazinyl} butanamides as tyrosinase and melanin inhibitors: In vitro, in vivo and in silico approaches
    Raza H, Abbasi MA, Aziz-Ur-Rehman, Siddiqui SZ, Hassan M, Abbas Q, et al.
    Bioorg Chem, 2020 01;94:103445.
    PMID: 31826809 DOI: 10.1016/j.bioorg.2019.103445
    In the current research work, different N-(substituted-phenyl)-4-{(4-[(E)-3-phenyl-2-propenyl]-1-piperazinyl}butanamides have been synthesized according to the protocol described in scheme 1. The synthesis was initiated by reacting various substituted anilines (1a-e) with 4-chlorobutanoyl chloride (2) in aqueous basic medium to give various electrophiles, 4-chloro-N-(substituted-phenyl)butanamides (3a-e). These electrophiles were then coupled with 1-[(E)-3-phenyl-2-propenyl]piperazine (4) in polar aprotic medium to attain the targeted N-(substituted-phenyl)-4-{(4-[(E)-3-phenyl-2-propenyl]-1-piperazinyl}butanamides (5a-e). The structures of all derivatives were identified and characterized by proton-nuclear magnetic resonance (1H NMR), carbon-nuclear magnetic resonance (13C NMR) and Infra-Red (IR) spectral data along with CHN analysis. The in vitro inhibitory potential of these butanamides was evaluated against Mushroom tyrosinase, whereby all compounds were found to be biologically active. Among them, 5b exhibited highest inhibitory potential with IC50 value of 0.013 ± 0.001 µM. The same compound 5b was also assayed through in vivo approach, and it was explored that it significantly reduced the pigments in zebrafish. The in silico studies were also in agreement with aforesaid results. Moreover, these molecules were profiled for their cytotoxicity through hemolytic activity, and it was found that except 5e, all other compounds showed minimal toxicity. The compound 5a also exhibited comparable results. Hence, some of these compounds might be worthy candidates for the formulation and development of depigmentation drugs with minimum side effects.
    Matched MeSH terms: Carbon Isotopes
  14. Fulltext Data on synthesis and characterization of new p-nitro stilbene Schiff bases derivatives as an electrochemical DNA potential spacer
    Mohd Izham NZ, Yusoff HM, Ul Haq Bhat I, Endo T, Fukumura H, Kwon E, et al.
    Data Brief, 2020 Jun;30:105568.
    PMID: 32368595 DOI: 10.1016/j.dib.2020.105568
    The structural investigation of synthesized compounds can be carried out by various spectroscopic techniques. It is an important prospect in order to elucidate the structure of the desired products before being further utilized. The preparation of new p-nitro stilbene Schiff base derivatives as an electrochemical DNA potential spacer was synthesized using (E)-4-(4-nitrostyryl)aniline from Heck reaction with aldehydes in ethanolic solution. The data presented here in this article contains FTIR, UV-Vis and 1H and 13C NMR of (E)-4-(4-nitrostyryl)aniline and nitrostyryl aniline derivatives.
    Matched MeSH terms: Carbon Isotopes
  15. Variation of δ2H, δ18O & δ13C in crude palm oil from different regions in Malaysia: Potential of stable isotope signatures as a key traceability parameter
    Muhammad SA, Seow EK, Mohd Omar AK, Rodhi AM, Mat Hassan H, Lalung J, et al.
    Sci Justice, 2018 Jan;58(1):59-66.
    PMID: 29332695 DOI: 10.1016/j.scijus.2017.05.008
    A total of 33 crude palm oil samples were randomly collected from different regions in Malaysia. Stable carbon isotopic composition (δ13C) was determined using Flash 2000 elemental analyzer while hydrogen and oxygen isotopic compositions (δ2H and δ18O) were analyzed by Thermo Finnigan TC/EA, wherein both instruments were coupled to an isotope ratio mass spectrometer. The bulk δ2H, δ18O and δ13C of the samples were analyzed by Hierarchical Cluster Analysis (HCA), Principal Component Analysis (PCA) and Orthogonal Partial Least Square-Discriminant Analysis (OPLS-DA). Unsupervised HCA and PCA methods have demonstrated that crude palm oil samples were grouped into clusters according to respective state. A predictive model was constructed by supervised OPLS-DA with good predictive power of 52.60%. Robustness of the predictive model was validated with overall accuracy of 71.43%. Blind test samples were correctly assigned to their respective cluster except for samples from southern region. δ18O was proposed as the promising discriminatory marker for discerning crude palm oil samples obtained from different regions. Stable isotopes profile was proven to be useful for origin traceability of crude palm oil samples at a narrower geographical area, i.e. based on regions in Malaysia. Predictive power and accuracy of the predictive model was expected to improve with the increase in sample size. Conclusively, the results in this study has fulfilled the main objective of this work where the simple approach of combining stable isotope analysis with chemometrics can be used to discriminate crude palm oil samples obtained from different regions in Malaysia. Overall, this study shows the feasibility of this approach to be used as a traceability assessment of crude palm oils.
    Matched MeSH terms: Carbon Isotopes
  16. Fulltext Inhibition of Mild Steel Corrosion in Hydrochloric Acid Solution by New Coumarin
    Kadhum AAH, Mohamad AB, Hammed LA, Al-Amiery AA, San NH, Musa AY
    Materials (Basel), 2014 Jun 05;7(6):4335-4348.
    PMID: 28788680 DOI: 10.3390/ma7064335
    A new coumarin derivative, N,N'-((2E,2'E)-2,2'-(1,4-phenylenebis (methanylylidene))bis(hydrazinecarbonothioyl))bis(2-oxo-2H-chromene-3-carboxamide) PMBH, was synthesized and its chemical structure was elucidated and confirmed using spectroscopic techniques (Infrared spectroscopy IR, Proton nuclear magnetic resonance, (1)H-NMR and carbon-13 nuclear magnetic resonance (13)C-NMR). The corrosion inhibition effect of PMBH on mild steel in 1.0 M HCl was investigated using corrosion potential (ECORR), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation (EFM) measurements. The obtained results indicated that PMBH has promising inhibitive effects on the corrosion of mild steel in 1.0 M HCl across all of the conditions examined. Scanning electron microscopy (SEM) was used to investigate the morphology of the mild steel before and after immersion in 1.0 M HCl solution containing 0.5 mM of PMBH. Surface analysis revealed improvement of corrosion resistance in presence of PMBH.
    Matched MeSH terms: Carbon Isotopes
  17. Fulltext Electrochemical Study on Newly Synthesized Chlorocurcumin as an Inhibitor for Mild Steel Corrosion in Hydrochloric Acid
    Al-Amiery AA, Kadhum AAH, Mohamad AB, Musa AY, Li CJ
    Materials (Basel), 2013 Nov 27;6(12):5466-5477.
    PMID: 28788402 DOI: 10.3390/ma6125466
    A new curcumin derivative, i.e., (1E,4Z,6E)-5-chloro-1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,4,6-trien-3-one (chlorocurcumin), was prepared starting with the natural compound curcumin. The newly synthesized compound was characterized by elemental analysis and spectral studies (IR, ¹H-NMR and 13C-NMR). The corrosion inhibition of mild steel in 1 M HCl by chlorocurcumin has been studied using potentiodynamic polarization (PDP) measurements and electrochemical impedance spectroscopy (EIS). The inhibition efficiency increases with the concentration of the inhibitor but decreases with increases in temperature. The potentiodynamic polarization reveals that chlorocurcumin is a mixed-type inhibitor. The kinetic parameters for mild steel corrosion were determined and discussed.
    Matched MeSH terms: Carbon Isotopes
  18. Fulltext 13C based proteinogenic amino acid (PAA) and metabolic flux ratio analysis of Lactococcus lactis reveals changes in pentose phosphate (PP) pathway in response to agitation and temperature related stresses
    Azizan KA, Ressom HW, Mendoza ER, Baharum SN
    PeerJ, 2017;5:e3451.
    PMID: 28695065 DOI: 10.7717/peerj.3451
    Lactococcus lactis subsp. cremoris MG1363 is an important starter culture for dairy fermentation. During industrial fermentations, L. lactis is constantly exposed to stresses that affect the growth and performance of the bacterium. Although the response of L. lactis to several stresses has been described, the adaptation mechanisms at the level of in vivo fluxes have seldom been described. To gain insights into cellular metabolism, 13C metabolic flux analysis and gas chromatography mass spectrometry (GC-MS) were used to measure the flux ratios of active pathways in the central metabolism of L. lactis when subjected to three conditions varying in temperature (30°C, 37°C) and agitation (with and without agitation at 150 rpm). Collectively, the concentrations of proteinogenic amino acids (PAAs) and free fatty acids (FAAs) were compared, and Pearson correlation analysis (r) was calculated to measure the pairwise relationship between PAAs. Branched chain and aromatic amino acids, threonine, serine, lysine and histidine were correlated strongly, suggesting changes in flux regulation in glycolysis, the pentose phosphate (PP) pathway, malic enzyme and anaplerotic reaction catalysed by pyruvate carboxylase (pycA). Flux ratio analysis revealed that glucose was mainly converted by glycolysis, highlighting the stability of L. lactis' central carbon metabolism despite different conditions. Higher flux ratios through oxaloacetate (OAA) from pyruvate (PYR) reaction in all conditions suggested the activation of pyruvate carboxylate (pycA) in L. lactis, in response to acid stress during exponential phase. Subsequently, more significant flux ratio differences were seen through the oxidative and non-oxidative pentose phosphate (PP) pathways, malic enzyme, and serine and C1 metabolism, suggesting NADPH requirements in response to environmental stimuli. These reactions could play an important role in optimization strategies for metabolic engineering in L. lactis. Overall, the integration of systematic analysis of amino acids and flux ratio analysis provides a systems-level understanding of how L. lactis regulates central metabolism under various conditions.
    Matched MeSH terms: Carbon Isotopes
  19. 13C-Urea Breath Test Accuracy for Helicobacter pylori Infection in the Asian Population: A Meta-Analysis
    Abd Rahim MA, Johani FH, Shah SA, Hassan MR, Abdul Manaf MR
    Ann Glob Health, 2019 Jul 24;85(1).
    PMID: 31348624
    BACKGROUND: Helicobacter pylori (H. pylori) infection is known to be associated with peptic ulcer and gastric cancer. Detection of H. pylori infection is a significant part of peptic ulcer and gastric cancer prevention and management. 13C-urea breath test (UBT) provides a good option for the pathogen detection due to its accuracy and safety.

    OBJECTIVE: This review aims to evaluate the 13C-UBT diagnostic accuracy studies conducted among Asian population and validate its use for the Asian population.

    METHODS: Original articles were systematically searched in PubMed, Scopus, and Google Scholar using the PICOS strategy by applying relevant keywords. Only studies published in English and conducted in Asia were included. Our search returned 276 articles. After assessment, 11 articles which answered our research question and met the criteria set for systematic review and meta-analysis were accepted. A total of 15 study protocols were extracted from the 11 accepted articles.

    FINDINGS: Majority of the studies were conducted in Hong Kong (six), followed by Taiwan (five), Japan (two), and one each in Singapore and Israel. All studies had used histology as part of its gold standard of reference. All but one study was performed on adult populations. The summary estimate for sensitivity was 97% (95% CI: 96, 98%), and specificity was 96% (95% CI: 95, 97%), with significant heterogeneity between studies. Adjusting for the dose (50 mg) and breath sample collection time (20 minutes) had improved both accuracy estimates and significantly reduced heterogeneity.

    CONCLUSION: This review supports the test-and-treat strategy for H. pylori infection management. Prevalence and cost-effectiveness studies are mandatory for health authorities to adopt this strategy into national policy.

    Matched MeSH terms: Carbon Isotopes
  20. Effects of tourism-derived sewage on coral reefs: Isotopic assessments identify effective bioindicators
    Lachs L, Johari NAM, Le DQ, Safuan CDM, Duprey NN, Tanaka K, et al.
    Mar Pollut Bull, 2019 Nov;148:85-96.
    PMID: 31422307 DOI: 10.1016/j.marpolbul.2019.07.059
    Pulau Redang and Pulau Tioman have experienced huge tourism growth over the last two decades, but minimal sewage treatment may threaten the resilience of their coral reefs. This study uses stable isotope techniques to identify suitable bioindicators of sewage nutrients (δ15N) at these islands by measuring macroalgae (Lobophora spp.), gastropods (Drupella spp.), scleractinian coral (Acropora spp.), and leather coral (Sinularia spp.). At tourist hubs using seepage septic tank systems, enrichment of Acropora δ15N (Redang, +0.7‰) and Sinularia δ15N (Tioman, +0.4‰) compared to pristine background levels indicate enhanced sewage nutrient discharge. Carbon isotopes and survey data suggest that sedimentation did not confound these δ15N trends. Potential damaging effects of sewage discharge on the coral reef communities at both islands are highlighted by strong correlations between Acropora δ15N and regional variation in coral reef community structure, and exclusive occurrence of degraded reefs at regions of high sewage influence.
    Matched MeSH terms: Carbon Isotopes/analysis
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