Displaying publications 221 - 240 of 535 in total

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  1. Fulltext Chemical constituents of aglaia lanuginose
    Kamarulzaman, F. A., Mohamad, K., Awang, K., Lee, H. B.
    Pertanika Journal of Science & Technology, 2014;22(1):163-174.
    MyJurnal
    Our continuing research on the Aglaia genus (family Meliaceace) has led us to this first study on the chemical constituents of Aglaia lanuginose (bark). The dichloromethane extract from the bark of Aglaia lanuginose showed cytotoxicity against HL-60 leukaemia cell line (45% inhibition) at 20 µg/ml and was prioritised for further investigation. Repeated chromatography of the dichloromethane extract yielded the known dammarane triterpenes which were identified as cabralealactone (1), methyl eichlerianate (2), cabraleone (3), ocotillone (4), eichleriatone (5), eichlerianic acid (6) and shoreic acid (7) together with the known sterols, sitosterol (9) and stigmasterol (10). Another isolated compound was the aromatic 4-hydroxycinnamyl-acetate (8), which has not been reported to be present in a plant from the Meliaceae family. The structures of all the compounds were elucidated on the basis of spectroscopic methods (IR, MS and NMR). Cytotoxicity testing of 1-10 showed activity only for mixtures of (3, 4), and (5, 6).
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  2. Fulltext Why metabonomics?
    Yap, Ivan K.S.
    International e-Journal of Science, Medicine & Education, 2011;5(1):17-26.
    MyJurnal
    Metabonomics can be used to quantitatively measure dynamic biochemical responses of living organisms to physiological or pathological stimuli. A range of analytical tools such as high-resolution nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) combined with multivariate statistical analysis can be employed to create comprehensive metabolic signatures of biological samples including urine, plasma, faecal water and tissue extracts. These metabolic signatures can reflect the physiological or pathological condition of the organism and indicate imbalances in the homeostatic regulation of tissues and extracellular fluids. This technology has been employed in a diverse range of application areas including investigation of disease mechanisms, diagnosis/prognosis of pathologies, nutritional interventions and drug toxicity. Metabolic profiling is becoming increasingly important in identifying biomarkers of disease progression and drug intervention, and can provide additional information to support or aid the interpretation of genomic and proteomic data. With the new generation of postgenomic technologies, the paradigm in many biological fields has shifted to either top down systems biology approaches, aiming to achieve a general understanding of the global and integrated response of an organism or to bottom up modelling of specific pathways and networks using a priori knowledge based on mining large bodies of literature. Whilst metabolic profiling lends itself to either approach, using it in an exploratory and hypothesis generating capacity clearly allows new mechanisms to be uncovered.
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  3. Fulltext Metabolite characterization of different palm date varieties and the correlation with their NO inhibitory activity, texture and sweetness
    Abdul-Hamid NA, Mediani A, Maulidiani M, Shadid K, Ismail IS, Abas F, et al.
    J Food Sci Technol, 2018 Apr;55(4):1541-1551.
    PMID: 29606769 DOI: 10.1007/s13197-018-3073-6
    The aim of this study was to examine the variation in metabolite constituents of five commercial varieties of date fruits; Ajwa, Safawi and Ambar which originated from Madinah, the Iranian Bam and Tunisian Deglet Noor. The differences of metabolome were investigated using proton nuclear magnetic resonance (1H NMR) spectroscopy combined with multivariate data analysis (MVDA). Principal Component Analysis (PCA) revealed clear separation between the date varieties. The Tunisian Deglet Noor demonstrated distinct cluster from the rest of the palm date samples based on the metabolite composition as shown by the pattern observed in Hierarchical Clustering Analysis (HCA) and PCA. Deglet Noor exhibited a significant higher level of sucrose (δ 5.40) and fructose (δ 4.16) in comparison with the other four varieties which can be associated with the distinctive sweet taste of this variety. Dates originated from Madinah and Tunisia exhibited a contrast manner in the amount of xylose and moisture content. These two aspects may contribute towards the soft texture of Tunisian dates. All Madinah dates were found to contain phenolic compounds which were well established as great antioxidant and anti-inflammatory agent. Ajwa dates exerted greater effect in inhibiting the generation of nitric oxide (NO) from the stimulated RAW264.7 cells at 95.37% inhibition. Succinic acid was suggested to have the most significant correlation with the trend of NO inhibitory shown by the selected date palm varieties.
    Matched MeSH terms: Proton Magnetic Resonance Spectroscopy
  4. Molecular structure, second- and third-order nonlinear optical properties and DFT studies of a novel non-centrosymmetric chalcone derivative: (2E)-3-(4-fluorophenyl)-1-(4-{[(1E)-(4-fluorophenyl)methylene]amino}phenyl)prop-2-en-1-one
    Maidur SR, Patil PS, Ekbote A, Chia TS, Quah CK
    Spectrochim Acta A Mol Biomol Spectrosc, 2017 Sep 05;184:342-354.
    PMID: 28528255 DOI: 10.1016/j.saa.2017.05.015
    In the present work, the title chalcone, (2E)-3-(4-fluorophenyl)-1-(4-{[(1E)-(4-fluorophenyl) methylene]amino}phenyl)prop-2-en-1-one (abbreviated as FAMFC), was synthesized and structurally characterized by single-crystal X-ray diffraction. The compound is crystallized in the monoclinic system with non-centrosymmetric space group P21 and hence it satisfies the essential condition for materials to exhibit second-order nonlinear optical properties. The molecular structure was further confirmed by using FT-IR and 1H NMR spectroscopic techniques. The title crystal is transparent in the Vis-NIR region and has a direct band gap. The third-order nonlinear optical properties were investigated in solution (0.01M) by Z-scan technique using a continuous wave (CW) DPSS laser at the wavelength of 532nm. The title chalcone exhibited significant two-photon absorption (β=35.8×10-5cmW-1), negative nonlinear refraction (n2=-0.18×10-8cm2W-1) and optical limiting (OL threshold=2.73kJcm-2) under the CW regime. In support of the experimental results, a comprehensive theoretical study was carried out on the molecule of FAMFC using density functional theory (DFT). The optimized geometries and frontier molecular orbitals were calculated by employing B3LYP/6-31+G level of theory. The optimized molecular structure was confirmed computationally by IR vibrational and 1H NMR spectral analysis. The experimental UV-Vis-NIR spectrum was interpreted using computational chemistry under time-dependent DFT. The static and dynamic NLO properties such as dipole moments (μ), polarizability (α), and first hyperpolarizabilities (β) were computed by using finite field method. The obtained dynamic first hyperpolarizability β(-2ω;ω,ω) at input frequency ω=0.04282a.u. is predicted to be 161 times higher than urea standard. The electronic excitation energies and HOMO-LUMO band gap for FAMFC were also evaluated by DFT. The experimental and theoretical results are in good agreement, and the NLO study suggests that FAMFC molecule can be a potential candidate in the nonlinear optical applications.
    Matched MeSH terms: Proton Magnetic Resonance Spectroscopy
  5. Fulltext Metabolites Re-programming and Physiological Changes Induced in Scenedesmus regularis under Nitrate Treatment
    Ma NL, Aziz A, Teh KY, Lam SS, Cha TS
    Sci Rep, 2018 06 27;8(1):9746.
    PMID: 29950688 DOI: 10.1038/s41598-018-27894-0
    Nitrate is required to maintain the growth and metabolism of plant and animals. Nevertheless, in excess amount such as polluted water, its concentration can be harmful to living organisms such as microalgae. Recently, studies on microalgae response towards nutrient fluctuation are usually limited to lipid accumulation for the production of biofuels, disregarding the other potential of microalgae to be used in wastewater treatments and as source of important metabolites. Our study therefore captures the need to investigate overall metabolite changes via NMR spectroscopy approach coupled with multivariate data to understand the complex molecular process under high (4X) and low (1/4X) concentrations of nitrate ([Formula: see text]). NMR spectra with the aid of chemometric analysis revealed contrasting metabolites makeup under abundance and limited nitrate treatment. By using NMR technique, 43 types of metabolites and 8 types of fatty acid chains were detected. Nevertheless, only 20 key changes were observed and 16 were down regulated in limited nitrate condition. This paper has demonstrated the feasibility of NMR-based metabolomics approach to study the physiological impact of changing environment such as pollution to the implications for growth and productivity of microalgae population.
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  6. 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: Proton Magnetic Resonance Spectroscopy
  7. Isolation and structure elucidation of triterpenes from inflorescence of banana (Musa balbisiana cv. Saba)
    Tin, H.S., Padam, B.S., Abdullah, M.I., Chye, F.Y.
    International Food Research Journal, 2016;23(2):866-872.
    MyJurnal
    The study aimed to isolate and elucidate the chemical compounds that are found in banana
    (Musa balbisiana cv. Saba) inflorescences. Banana inflorescence buds were extracted using
    methanol and the resulted methanolic extract was partitioned using chloroform, ethyl acetate
    and butanol against deionized water. The chloroform partition was further separated into
    fractions using column chromatography assisted by thin layer chromatography. The structure
    elucidation was performed using nuclear magnetic resonance spectrometry (NMR). Three
    triterpenes were isolated namely 31-norcyclolaudenone (1), cycloartenol (2) and (24R)-4a,24-
    trimethyl-5a-cholesta-8,25(27)-dien-3b-ol (3). This is the first report on the isolation of these
    triterpenes from Musa balbisiana inflorescence. The discovery of new triterpenes from banana
    inflorescence should be further explored to open a new perspective that banana by-products
    might serve as new source of natural products for food and pharmaceutical applications.
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  8. Design, Synthesis and Biological Potential of 5-(2-Amino-6-(3/4-bromophenyl)pyrimidin-4-yl)benzene-1,3-diol Scaffolds as Promising Antimicrobial and Anticancer Agents
    Kumar S, Narasimhan B, Lim SM, Ramasamy K, Mani V, Shah SAA
    Mini Rev Med Chem, 2019;19(10):851-864.
    PMID: 30306864 DOI: 10.2174/1389557518666181009141924
    BACKGROUND: A series of 5-(2-amino-6-(3/4-bromophenyl)pyrimidin-4-yl)benzene-1,3-diol scaffolds was synthesized by Claisen-Schmidt condensation and characterized by NMR, IR, Mass and elemental analyses.

    METHODS: The synthesized pyrimidine scaffolds were screened for their antimicrobial activity by tube dilution method as well for antiproliferative activity (human colorectal (HCT116) cancer cell line) by SRB assay.

    RESULTS: The antimicrobial screening results demonstrated that compounds, k6, k12, k14 and k20 were found to be the most potent ones against selected microbial species. The anticancer screening results indicated that compounds, k8 and k14 displayed potent anticancer activity against cancer cell line (HCT116).

    CONCLUSION: Further, the molecular docking study carried to find out the interaction between active pyrimidine compounds with CDK-8 protein indicated that compound k14 showed best dock score with better potency within the ATP binding pocket and may be used as a lead for rational drug designing of the anticancer molecule.

    Matched MeSH terms: Magnetic Resonance Spectroscopy
  9. 13C-NMR dereplication of Garcinia extracts: Predicted chemical shifts as reliable databases
    Bruguière A, Derbré S, Coste C, Le Bot M, Siegler B, Leong ST, et al.
    Fitoterapia, 2018 Nov;131:59-64.
    PMID: 30321650 DOI: 10.1016/j.fitote.2018.10.003
    Usually isolated from Garcinia (Clusiaceae) or Hypericum (Hypericaceae) species, some Polycyclic Polyprenylated AcylPhloroglucinols (PPAPs) have been recently reported as potential research tools for immunotherapy. Aiming at exploring the chemodiversity of PPAPs amongst Garcinia genus, a dereplication process suitable for such natural compounds has been developed. Although less sensitive than mass spectrometry, NMR spectroscopy is perfectly reproducible and allows stereoisomers distinction, justifying the development of 13C-NMR strategies. Dereplication requires the use of databases (DBs). To define if predicted DBs were accurate enough as dereplication tools, experimental and predicted δC of natural products usually isolated from Clusiaceae were compared. The ACD/Labs commercial software allowed to predict 73% of δC in a 1.25 ppm range around the experimental values. Consequently, with these parameters, the major PPAPs from a Garcinia bancana extract were successfully identified using a predicted DB.
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  10. 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-13 Magnetic Resonance Spectroscopy
  11. Fulltext The extraction of Vitex pouch
    Mohd Ali, A., Jahidin, A.H., Abdul Wahab, I., Mohsin, H.F., Mizaton, H.H.
    Journal of Academia Universiti Teknologi MARA Negeri Sembilan, 2018;6(1):1-7.
    MyJurnal
    In this study, the unprecedented extraction of the Vitex pouch was performed. The compounds from
    methanolic and chloroform extracts were isolated by using thin layer chromatography (TLC). The
    compound of interest was investigated by using 1H-Nuclear Magnetic Resonance (NMR, 500 MHz)
    spectroscopy. From the NMR spectral examination, the compound from the methanolic extract was
    suggested as glucononitol. Indeed, there are some parameters that could enhance the attainment of this
    research, which include high performance liquid chromatographic supplies. Nevertheless, more
    information and understanding on the pharmaceutical and chemical analysis of the Vitex species were
    obtained. To sum up, it is anticipated that incoming research with advanced technology for this
    natural product could be explored in the future.
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  12. Metal substitutions incarbonic anhydrase: a halide ion probe study
    Smith RJ, Bryant RG
    Biochem Biophys Res Commun, 1975 Oct 27;66(4):1281-6.
    PMID: 3
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  13. Metabolomics in Systems Biology
    Baharum SN, Azizan KA
    Adv Exp Med Biol, 2018 11 2;1102:51-68.
    PMID: 30382568 DOI: 10.1007/978-3-319-98758-3_4
    Over the last decade, metabolomics has continued to grow rapidly and is considered a dynamic technology in envisaging and elucidating complex phenotypes in systems biology area. The advantage of metabolomics compared to other omics technologies such as transcriptomics and proteomics is that these later omics only consider the intermediate steps in the central dogma pathway (mRNA and protein expression). Meanwhile, metabolomics reveals the downstream products of gene and expression of proteins. The most frequently used tools are nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). Some of the common MS-based analyses are gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). These high-throughput instruments play an extremely crucial role in discovery metabolomics to generate data needed for further analysis. In this chapter, the concept of metabolomics in the context of systems biology is discussed and provides examples of its application in human disease studies, plant responses towards stress and abiotic resistance and also microbial metabolomics for biotechnology applications. Lastly, a few case studies of metabolomics analysis are also presented, for example, investigation of an aromatic herbal plant, Persicaria minor metabolome and microbial metabolomics for metabolic engineering applications.
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  14. Effect of extraction methods on the molecular structure and thermal stability of kenaf (Hibiscus cannabinus core) biomass as an alternative bio-filler for rubber composites
    Mohamad Aini NA, Othman N, Hussin MH, Sahakaro K, Hayeemasae N
    Int J Biol Macromol, 2020 Jul 01;154:1255-1264.
    PMID: 31765744 DOI: 10.1016/j.ijbiomac.2019.10.280
    Lignin from kenaf (Hibiscus cannabinus) core was investigated as an alternative filler for rubber. Three types of extraction methods were used to isolate lignin from kenaf, namely kraft, soda and organosolv process. The particle size, surface area, functionalities changes, molecular weight and thermal properties of the lignin were characterized. The results showed that Kraft lignin (KL) has the smallest particle size (40.41 μm) compared to soda lignin (SL) (63.85 μm) and organosolv lignin (OL) (66.85 μm). This is in good agreement with the BET surface area of 9.52 m2/g, 1.25 m2/g and 2.40 m2/g respectively. However, the smaller surface area of SL compared to OL is due to the smaller pore size and pore volume of SL. KL also showed high hydroxyl content with corresponding high thermal stability as confirmed by NMR and TGA. The thermal stability of the lignin correlates well with the molecular weight (MW). From the overall characteristics, it can be concluded that KL, SL and OL can be used as an alternative filler in rubber compounds to substitute common fillers like silica and carbon.
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  15. Microenvironmental Interplay Predominated by Beneficial Aspergillus Abates Fungal Pathogen Incidence in Paddy Environment
    Fan X, Matsumoto H, Wang Y, Hu Y, Liu Y, Fang H, et al.
    Environ Sci Technol, 2019 Nov 19;53(22):13042-13052.
    PMID: 31631659 DOI: 10.1021/acs.est.9b04616
    Rice fungal pathogens, responsible for severe rice yield loss and biotoxin contamination, cause increasing concerns on environmental safety and public health. In the paddy environment, we observed that the asymptomatic rice phyllosphere microenvironment was dominated by an indigenous fungus, Aspergillus cvjetkovicii, which positively correlated with alleviated incidence of Magnaporthe oryzae, one of the most aggressive plant pathogens. Through the comparative metabolic profiling for the rice phyllosphere microenvironment, two metabolites were assigned as exclusively enriched metabolic markers in the asymptomatic phyllosphere and increased remarkably in a population-dependent manner with A. cvjetkovicii. These two metabolites evidenced to be produced by A. cvjetkovicii in either a phyllosphere microenvironment or artificial media were purified and identified as 2(3H)-benzofuranone and azulene, respectively, by gas chromatography coupled to triple quadrupole mass spectrometry and nuclear magnetic resonance analyses. Combining with bioassay analysis in vivo and in vitro, we found that 2(3H)-benzofuranone and azulene exerted dissimilar actions at the stage of infection-related development of M. oryzae. A. cvjetkovicii produced 2(3H)-benzofuranone at the early stage to suppress MoPer1 gene expression, leading to inhibited mycelial growth, while azulene produced lately was involved in blocking of appressorium formation by downregulation of MgRac1. More profoundly, the microenvironmental interplay dominated by A. cvjetkovicii significantly blocked M. oryzae epidemics in the paddy environment from 54.7 to 68.5% (p < 0.05). Our study first demonstrated implication of the microenvironmental interplay dominated by indigenous and beneficial fungus to ecological balance and safety of the paddy environment.
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  16. Synthesis and characterization of esters derived from ricinoleic acid and evaluation of their low temperature property
    Jumat Salimon, Nadia Salih, Yousif E
    Sains Malaysiana, 2012;41:1239-1244.
    A series of ester compounds derived from ricinoleic acid to be used as biolubricants base stock have been synthesized. The resulting products were confirmed by FTIR and NMR analyses. The synthesis was carried out in three stages: epoxidation of ricinoleic acid; synthesis of 10,12-dihydroxy-9-acyloxystearic acid from epoxidized ricinoleic acid with various fatty acids and esterification of the acyloxystearic acid products with octanol to yield octyl-10,12-dihydroxy-9-acyloxystearate. The viscosities, flash points and pour points (PP) behavior of the products were measured. The resulting esters had an increased in molar weight and viscosity and decreased in pour points as compared to ricinoleic acid.
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  17. Chemical constituents from the fruit peel of Goniothalamus scortechinii
    Aryanti Abdullah, Zuriati Zakaria, Fasihuddin Ahmad, Mat-Salleh K, Laily B. Din
    Sains Malaysiana, 2009;38.
    The phytochemical investigation on the fruit peel of Goniothalamus scortechinii (Selayar Raja Ubat) obtained from Gunung Stong, Kelantan has resulted in the isolation of five compounds namely pinocembrine, altholactone, goniofufurone, goniotriol and goniopypyrone. Their structures were determined by extensive ultra violet (UV), infrared (IR), nuclear magnetic resonance (NMR) spectroscopy and gas chromatography-mass spectrum (GCMS) analysis.
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  18. A novel ruthenium-tungsten bimetallic complex dye-sensitizer for photoelectrochemical cells application
    Khuzaimah Arifin, Wan Ramli Wan Daud, Mohammad B. Kassim
    Sains Malaysiana, 2014;43:95-101.
    A novel bimetallic double thiocyanate-bridged ruthenium and tungsten metal complex containing bipyridyl and dithiolene co-ligands was synthesized and the behavior of the complex as a dye-sensitizer for a photoelectrochemical (PEG) cell for a direct water splitting reaction was investigated. The ligands and metal complexes were characterized on the basis of elemental analysis as well as uv-Vis, Fourier transform infrared ( Pim) and nuclear magnetic resonance (11I and 13C NMR) spectroscopy. Cyclic voltammetry of the bimetallic complex showed multiple redox couples, in which half potentials E 112 at 0 .625 , 0.05 and 0.61 V were assigned as the formal redox processes of Ru(III)IRu(II) reduction, W(IV)IW(V) and W(V)IW(VI) oxidations, respectively. Photocurrent measurements were performed in homogeneous system and TiO2 was used as the photoanode for photocurrent measurements. Current density generated by the bimetallic complex was higher than that of N3 commercial dye which suggested that the bimetallic complex donated more electrons to the semiconductor.
    Matched MeSH terms: Carbon-13 Magnetic Resonance Spectroscopy
  19. California bearing ratio tests of enzyme-treated sedimentary residual soil show no improvement
    Tanveer Ahmed Khan, Mohd Raihan Taha, Ali Asghar Firoozi, Ali Akbar Firoozi
    Sains Malaysiana, 2017;46:1269-1267.
    Environmental concerns have significantly influenced the construction industry regarding the identification and use of environmentally sustainable construction materials. In this context, enzymes (organic materials) have been introduced recently for ground improvement projects such as pavements and embankments. The present experimental study was carried out in order to evaluate the compressive strength of a sedimentary residual soil treated with three different types of enzymes, as assessed through a California bearing ratio (CBR) test. Controlled untreated and treated soil samples containing four dosages (the recommended dose and two, five and 10 times the recommended dose) were prepared, sealed and cured for four months. Following the curing period, samples were soaked in water for four days before the CBR tests were administered. These tests showed no improvement in the soil is compressive strength; in other words, samples prepared even at higher dosages did not exhibit any improvement. Nuclear magnetic resonance (NMR) spectroscopy tests were carried out on three enzymes in order to study the functional groups present in them. Furthermore, X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) tests were executed for untreated and treated soil samples to determine if any chemical reaction took place between the soil and the enzymes. Neither of the tests (XRD nor FESEM) revealed any change. In fact, the XRD patterns and FESEM images for untreated and treated soil samples were indistinguishable.
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  20. Interaction study of binary solvent systems ionic liquid and deep eutectic solvent with rotenone
    Zetty Shafiqa Othman, Nurul Huda Abd Karim, Saiful Irwan Zubairi, Nur Hasyareeda Hassan, Mamoru Koketsu
    Sains Malaysiana, 2018;47:1473-1482.
    [BMIM]OTf and alcohol-based DES combination with a selected organic solvent (acetone and acetonitrile) have
    been proven to efficiently extracting rotenone (isoflavonoid biopesticide) compound compared to individual organic
    solvents. Their efficiency builds up interest to study the solvent-solute interaction that occurs between both selected
    solvent systems with rotenone. The interaction study was analyzed using FTIR, 1D-NMR and 2D- NMR (NOESY, HMBC).
    Correlation portrayed by NOESY and HMBC of [BMIM]OTf - standard rotenone mixture predicted probable hydrogen
    bonding between the oxygen of rotenone with acidic proton C2-H of [BMIM]OTf. While for the alcohol-based DESrotenone
    mixture, the correlation shows probable interaction to occur between methyl and methoxy group rotenone
    with the hydroxyl group of 1,4-butanediol. In conclusion, potential hydrogen bonding that occurs between solvent
    and solute aid towards the solvent efficiency in extracting rotenone compound while emphasizing on the low cost and
    green mediated solvent systems.
    Matched MeSH terms: Magnetic Resonance Spectroscopy
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