Displaying publications 1 - 20 of 88 in total

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  1. Microbial Community Structure in a Malaysian Tropical Peat Swamp Forest: The Influence of Tree Species and Depth
    Too CC, Keller A, Sickel W, Lee SM, Yule CM
    Front Microbiol, 2018;9:2859.
    PMID: 30564202 DOI: 10.3389/fmicb.2018.02859
    Tropical peat swamp forests sequester globally significant stores of carbon in deep layers of waterlogged, anoxic, acidic and nutrient-depleted peat. The roles of microbes in supporting these forests through the formation of peat, carbon sequestration and nutrient cycling are virtually unknown. This study investigated physicochemical peat properties and microbial diversity between three dominant tree species: Shorea uliginosa (Dipterocarpaceae), Koompassia malaccensis (legumes associated with nitrogen-fixing bacteria), Eleiodoxa conferta (palm) and depths (surface, 45 and 90 cm) using microbial 16S rRNA gene amplicon sequencing. Water pH, oxygen, nitrogen, phosphorus, total phenolic contents and C/N ratio differed significantly between depths, but not tree species. Depth also strongly influenced microbial diversity and composition, while both depth and tree species exhibited significant impact on the archaeal communities. Microbial diversity was highest at the surface, where fresh leaf litter accumulates, and nutrient supply is guaranteed. Nitrogen was the core parameter correlating to microbial communities, but the interactive effects from various environmental variables displayed significant correlation to relative abundance of major microbial groups. Proteobacteria was the dominant phylum and the most abundant genus, Rhodoplanes, might be involved in nitrogen fixation. The most abundant methanogens and methanotrophs affiliated, respectively, to families Methanomassiliicoccaceae and Methylocystaceae. Our results demonstrated diverse microbial communities and provide valuable insights on microbial ecology in these extreme ecosystems.
  2. Development and validation of a questionnaire on perceived prosthodontic treatment needs in Malaysian adults
    Soo SY, Lee SM, Tew IM, Mohd Dom TN, Yahya NA
    J Prosthet Dent, 2023 Jul 17.
    PMID: 37468369 DOI: 10.1016/j.prosdent.2023.06.003
    STATEMENT OF PROBLEM: A discrepancy between dentists' assessments and patients' expectations during prosthodontic treatment is inevitable. Incorporating dental patients' concerns about their prosthodontic treatment needs is essential during treatment planning, yet studies assessing these needs in adult dental patients are lacking.

    PURPOSE: The purpose of this study was to develop and validate a novel instrument, termed the questionnaire on perceived prosthodontic treatment needs (PPTN), that assesses perceived prosthodontic treatment needs in adults.

    MATERIAL AND METHODS: The PPTN was developed following a literature review, consultation with healthcare workers, and patient interviews. It included 15 questions and a self-rated need for prosthodontic treatment, categorized on a Likert scale. A cross-sectional descriptive study was completed on 193 dental patients seeking or receiving prosthodontic treatment.

    RESULTS: Three perceived prosthodontic treatment need factors were identified (psychosocial impact, esthetic concern, and function) by using exploratory factor analysis. A higher PPTN score indicated greater perceived prosthodontic treatment needs. The identified factors represent 67.8% of the variance with eigenvalues of >1. The PPTN had a high degree of internal consistency and reliability, as the final questionnaire received a Cronbach alpha of 0.75 and an intraclass coefficient of 0.75 with a 95% confidence interval of 0.68 to 0.80 (F(192, 576)=3.94, P

  3. Fulltext Survival in hepatitis-B cirrhosis compared to alcoholic cirrhosis in patients with Child's C liver disease: a prospective study of endoscopic sclerotherapy for bleeding oesophageal varices
    Lee SM, Wong NW
    Singapore Med J, 1994 Feb;35(1):53-6.
    PMID: 8009280
    A prospective comparative study was carried out on thirty-seven consecutive patients presenting with bleeding oesophageal varices at University Hospital, Kuala Lumpur. All patients received injection sclerotherapy if active bleeding was seen at the time of initial endoscopy, followed by repetitive courses of sclerotherapy to obliterate the varices. Predominant aetiological factors were hepatitis-B cirrhosis (43%) and alcoholic cirrhosis (30%). Chinese ethnic group accounted for 62.5% of hepatitis-B cirrhotics and Indian 73% of alcoholic cirrhotics. After excluding patients lost to follow-up, analysis of the remaining thirty-four patients showed reduced long-term survival in patients with Child's C disease. Log-rank analysis of survival curves between hepatitis-B cirrhosis and alcoholic cirrhosis in patients with Child's C liver disease showed no significant difference in long-term survival (p = 0.07). However, six deaths were seen in hepatitis-B cirrhosis compared to one death in alcoholic cirrhosis in the first eight months of follow-up. Most patients died from progressive liver failure. Median survival for Child's C hepatitis-B cirrhosis was 7.5 months whereas this had not been reached for Child's C alcoholic cirrhosis (median follow-up 11.6 months). We conclude that variceal haemorrhage in Child's C hepatitis-B cirrhosis is a bad prognostic sign and is associated with reduced survival with a median survival of 7.5 months despite control of the variceal bleed.
  4. Fulltext Secondary bonding in di-methyl-bis-(morpholine-4-carbodi-thio-ato-κ(2)S,S')tin(IV): crystal structure and Hirshfeld surface analysis
    Zaldi NB, Hussen RSD, Lee SM, Halcovitch NR, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2017 Jun 01;73(Pt 6):842-848.
    PMID: 28638641 DOI: 10.1107/S2056989017006855
    The title compound, [Sn(CH3)2(C5H8NOS2)2], has the Sn(IV) atom bound by two methyl groups which lie over the weaker Sn-S bonds formed by two asymmetrically chelating di-thio-carbamate ligands so that the coordination geometry is skew-trapezoidal bipyramidal. The most prominent feature of the mol-ecular packing are secondary Sn⋯S inter-actions [Sn⋯S = 3.5654 (7) Å] that lead to centrosymmetric dimers. These are connected into a three-dimensional architecture via methyl-ene-C-H⋯S and methyl-C-H⋯O(morpholino) inter-actions. The Sn⋯S inter-actions are clearly evident in the Hirshfeld surface analysis of the title compound along with a number of other inter-molecular contacts.
  5. Fulltext trans-Di-chlorido-bis-(dimethyl sulfoxide-κO)bis-(4-fluoro-benzyl-κC(1))tin(IV): crystal structure and Hirshfeld surface analysis
    Amin NABM, Hussen RSD, Lee SM, Halcovitch NR, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2017 May 01;73(Pt 5):667-672.
    PMID: 28529772 DOI: 10.1107/S2056989017005072
    The Sn(IV) atom in the title diorganotin compound, [Sn(C7H6F)2Cl2(C2H6OS)2], is located on a centre of inversion, resulting in the C2Cl2O2 donor set having an all-trans disposition of like atoms. The coordination geometry approximates an octa-hedron. The crystal features C-H⋯F, C-H⋯Cl and C-H⋯π inter-actions, giving rise to a three-dimensional network. The respective influences of the Cl⋯H/H⋯Cl and F⋯H/H⋯F contacts to the mol-ecular packing are clearly evident from the analysis of the Hirshfeld surface.
  6. Fulltext N'-[1-(5-Bromo-2-hy-droxy-phen-yl)ethyl-idene]isonicotinohydrazide monohydrate: crystal structure and Hirshfeld surface analysis
    Lee SM, Halcovitch NR, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2017 Apr 01;73(Pt 4):630-636.
    PMID: 28435737 DOI: 10.1107/S2056989017004790
    In the title isonicotinohydrazide hydrate, C14H12BrN3O2·H2O {systematic name: N'-[(1E)-1-(5-bromo-2-hy-droxy-phen-yl)ethyl-idene]pyridine-4-carbohydrazide monohydrate}, the central CN2O region of the organic mol-ecule is planar and the conformation about the imine-C=N bond is E. While an intra-molecular hy-droxy-O-H⋯N(imine) hydrogen bond is evident, the dihedral angle between the central residue and the benzene rings is 48.99 (9)°. Overall, the mol-ecule is twisted, as seen in the dihedral angle of 71.79 (6)° between the outer rings. In the crystal, hydrogen-bonding inter-actions, i.e. hydrazide-N-H⋯O(water), water-O-H⋯O(carbon-yl) and water-O-H⋯N(pyrid-yl), lead to supra-molecular ribbons along the a-axis direction. Connections between these, leading to a three-dimensional architecture, are mediated by Br⋯Br halogen bonding [3.5366 (3) Å], pyridyl-C-H⋯O(carbon-yl) as well as weak π-π inter-actions [inter-centroid separation between benzene rings = 3.9315 (12) Å]. The Hirshfeld surface analysis reveals the importance of hydrogen atoms in the supra-molecular connectivity as well as the influence of the Br⋯Br halogen bonding.
  7. 1-Chloro-4-[2-(4-chloro-phen-yl)eth-yl]benzene and its bromo analogue: crystal structure, Hirshfeld surface analysis and computational chemistry
    Jotani MM, Lee SM, Lo KM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2019 May 01;75(Pt 5):624-631.
    PMID: 31110800 DOI: 10.1107/S2056989019004742
    The crystal and mol-ecular structures of C14H12Cl2, (I), and C14H12Br2, (II), are described. The asymmetric unit of (I) comprises two independent mol-ecules, A and B, each disposed about a centre of inversion. Each mol-ecule approximates mirror symmetry [the Cb-Cb-Ce-Ce torsion angles = -83.46 (19) and 95.17 (17)° for A, and -83.7 (2) and 94.75 (19)° for B; b = benzene and e = ethyl-ene]. By contrast, the mol-ecule in (II) is twisted, as seen in the dihedral angle of 59.29 (11)° between the benzene rings cf. 0° in (I). The mol-ecular packing of (I) features benzene-C-H⋯π(benzene) and Cl⋯Cl contacts that lead to an open three-dimensional (3D) architecture that enables twofold 3D-3D inter-penetration. The presence of benzene-C-H⋯π(benzene) and Br⋯Br contacts in the crystal of (II) consolidate the 3D architecture. The analysis of the calculated Hirshfeld surfaces confirm the influence of the benzene-C-H⋯π(benzene) and X⋯X contacts on the mol-ecular packing and show that, to a first approximation, H⋯H, C⋯H/H⋯C and C⋯X/X⋯C contacts dominate the packing, each contributing about 30% to the overall surface in each of (I) and (II). The analysis also clearly differentiates between the A and B mol-ecules of (I).
  8. (Tris{2-[(5-chloro-2-oxido-benzyl-idene-κO)amino-κN]eth-yl}amine-κN)-ytterbium(III): crystal structure and Hirshfeld surface analysis
    Lee SM, Lo KM, Tan SL, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2016 Oct 1;72(Pt 10):1390-1395.
    PMID: 27746926
    The Yb(III) atom in the title complex, [Yb(C27H24Cl3N4O3)] [systematic name: (2,2',2''-{(nitrilo)-tris-[ethane-2,1-di-yl(nitrilo)-methylyl-idene]}tris-(4-chloro-phenolato)ytterbium(III)], is coordinated by a trinegative, hepta-dentate ligand and exists within an N4O3 donor set, which defines a capped octa-hedral geometry whereby the amine N atom caps the triangular face defined by the three imine N atoms. The packing features supra-molecular layers that stack along the a axis, sustained by a combination of aryl-C-H⋯O, imine-C-H⋯O, methyl-ene-C-H⋯π(ar-yl) and end-on C-Cl⋯π(ar-yl) inter-actions. A Hirshfeld surface analysis points to the major contributions of C⋯H/ H⋯C and Cl⋯H/H⋯Cl inter-actions (along with H⋯H) to the overall surface but the Cl⋯H contacts are at distances greater than the sum of their van der Waals radii.
  9. Fulltext fac-Aceto-nitrile-tricarbon-yl(di-methyl-carbamodi-thio-ato-κ(2)S,S')rhenium(I): crystal structure and Hirshfeld surface analysis
    Tan SL, Lee SM, Heard PJ, Halcovitch NR, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2017 Feb 01;73(Pt 2):213-218.
    PMID: 28217345 DOI: 10.1107/S2056989017000755
    The title compound, [Re(C3H6NS2)(C2H3N)(CO)3], features an octa-hedrally coordinated Re(I) atom within a C3NS2 donor set defined by three carbonyl ligands in a facial arrangement, an aceto-nitrile N atom and two S atoms derived from a symmetrically coordinating di-thio-carbamate ligand. In the crystal, di-thio-carbamate-methyl-H⋯O(carbon-yl) inter-actions lead to supra-molecular chains along [36-1]; both di-thio-carbamate S atoms participate in intra-molecular methyl-H⋯S inter-actions. Further but weaker aceto-nitrile-C-H⋯O(carbonyl) inter-actions assemble mol-ecules in the ab plane. The nature of the supra-molecular assembly was also probed by a Hirshfeld surface analysis. Despite their weak nature, the C-H⋯O contacts are predominant on the Hirshfeld surface and, indeed, on those of related [Re(CO)3(C3H6NS2)L] structures.
  10. Fulltext Bis(μ2-N-methyl-N-phenyl-dithio-carbamato)-κ(3)S,S':S;κ(3)S:S,S'-bis-[(N-methyl-N-phenyl-dithio-carbamato-κ(2)S,S')cadmium]: crystal structure and Hirshfeld surface analysis
    Suwardi SA, Lee SM, Lo KM, Jotani MM, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2017 Mar 01;73(Pt 3):429-433.
    PMID: 28316825 DOI: 10.1107/S2056989017002705
    The title compound, [Cd2(C8H8NS2)4], is a centrosymmetric dimer with both chelating and μ2-tridentate di-thio-carbamate ligands. The resulting S5 donor set defines a Cd(II) coordination geometry inter-mediate between square-pyramidal and trigonal-bipyramidal, but tending towards the former. The packing features C-H⋯S and C-H⋯π inter-actions, which generate a three-dimensional network. The influence of these inter-actions, along with intra-dimer π-π inter-actions between chelate rings, has been investigated by an analysis of the Hirshfeld surface.
  11. Zwitterionic 4-bromo-6-meth-oxy-2-{[tris-(hy-droxy-meth-yl)methyl]-iminiumyl-meth-yl}phenolate: crystal structure and Hirshfeld surface analysis
    Lee SM, Lo KM, Tan SL, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2016 Aug 1;72(Pt 8):1223-7.
    PMID: 27536419 DOI: 10.1107/S2056989016012159
    In the solid state, the title compound, C12H16BrNO5 [systematic name: 4-bromo-2-((1E)-{[1,3-dihy-droxy-2-(hy-droxy-meth-yl)propan-2-yl]iminium-yl}meth-yl)-6-meth-oxy-benzen-1-olate], C12H16BrNO5, is found in the keto-amine tautomeric form, with an intra-molecular iminium-N-H⋯O(phenolate) hydrogen bond and an E conformation about the C=N bond. Both gauche (two) and anti relationships are found for the methyl-hydroxy groups. In the crystal, a supra-molecular layer in the bc plane is formed via hy-droxy-O-H⋯O(hy-droxy) and charge-assisted hy-droxy-O-H⋯O(phenolate) hydrogen-bonding inter-actions; various C-H⋯O inter-actions provide additional cohesion to the layers, which stack along the a axis with no directional inter-actions between them. A Hirshfeld surface analysis confirms the lack of specific inter-actions in the inter-layer region.
  12. Fulltext [N'-(4-Dec-yloxy-2-oxido-benzyl-idene)-3-hy-droxy-2-naphtho-hydrazidato-κ3N,O,O']di-methyl-tin(IV): crystal structure and Hirshfeld surface analysis
    Rosely SN, Hussen RS, Lee SM, Halcovitch NR, Jotani MM, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2017 Mar 01;73(Pt 3):390-396.
    PMID: 28316817 DOI: 10.1107/S2056989017002365
    The title diorganotin compound, [Sn(CH3)2(C28H32N2O4)], features a distorted SnC2NO2 coordination geometry almost inter-mediate between ideal trigonal-bipyramidal and square-pyramidal. The dianionic Schiff base ligand coordinates in a tridentate fashion via two alkoxide O and hydrazinyl N atoms; an intra-molecular hy-droxy-O-H⋯N(hydrazin-yl) hydrogen bond is noted. The alk-oxy chain has an all-trans conformation, and to the first approximation, the mol-ecule has local mirror symmetry relating the two Sn-bound methyl groups. Supra-molecular layers sustained by imine-C-H⋯O(hy-droxy), π-π [between dec-yloxy-substituted benzene rings with an inter-centroid separation of 3.7724 (13) Å], C-H⋯π(arene) and C-H⋯π(chelate ring) inter-actions are formed in the crystal; layers stack along the c axis with no directional inter-actions between them. The presence of C-H⋯π(chelate ring) inter-actions in the crystal is clearly evident from an analysis of the calculated Hirshfeld surface.
  13. Chitinophaga extrema sp. nov., isolated from subsurface soil and leaf litter in a tropical peat swamp forest
    Goh CBS, Wong LW, Parimannan S, Rajandas H, Loke S, Croft L, et al.
    Int J Syst Evol Microbiol, 2020 Dec;70(12):6355-6363.
    PMID: 33146596 DOI: 10.1099/ijsem.0.004539
    A Gram-negative, filamentous aerobic bacterium designated as strain Mgbs1T was isolated on 12 April 2017 from the subsurface soil and leaf litter substrate at the base of a Koompassia malaccensis tree in a tropical peat swamp forest in the northern regions of the state of Selangor, Malaysia (3° 39' 04.7' N 101° 17' 43.7'' E). Phylogenetic analyses based on the full 16S rRNA sequence revealed that strain Mgbs1T belongs to the genus Chitinophaga with the greatest sequence similarity to Chitinophaga terrae KP01T (97.65 %), Chitinophaga jiangningensis DSM27406T (97.58 %), and Chitinophaga dinghuensis DHOC24T (97.17 %). The major fatty acids of strain Mgbs1T (>10 %) are iso-C15 : 0, C16 : 1 ω5c and iso-C17 : 0 3-OH while the predominant respiratory quinone is menaquinone-7. Strain Mgbs1T has a complete genome size of 8.03 Mb, with a G+C content of 48.5 mol%. The DNA-DNA hybridization (DDH) score between strain Mgbs1T and C. jiangningensis DSM27406T was 15.9 %, while in silico DDH values of strain Mgbs1T against C. dinghuensis DHOC24T and C. terrae KP01T were 20.0 and 19.10% respectively. Concurrently, Average Nucleotide Identity (ANI) scores between strain Mgbs1T against all three reference strains are 73.2 %. Based on the phenotypic, chemotaxonomic, and phylogenetic consensus, strain Mgbs1T represents a novel species of the genus Chitinophaga, for which the name Chitinophaga extrema sp. nov. is proposed (=DSM 108835T=JCM 33276T).
  14. Fulltext First reported case of Gilbertella persicaria in human stool: outcome of a community study from Segamat, Johor, Malaysia
    Huët MAL, Wong LW, Goh CBS, Ong KS, Dwiyanto J, Reidpath D, et al.
    Braz J Microbiol, 2020 Dec;51(4):2067-2075.
    PMID: 32572838 DOI: 10.1007/s42770-020-00323-z
    Species of fungi belonging to the order Mucorales can be found everywhere in the environment. Gilbertella persicaria, which belongs to this order, have often been isolated from fruits and in water systems. However, there has been no report of isolation of this fungus from human samples. During a gut mycobiome study, from the Segamat community, Gilbertella persicaria was isolated from a human fecal sample and was characterized through a series of morphological assessment, biochemical tests, and molecular techniques. The isolate produced a white velvety surface that turned grayish after 24 h. Although no biofilm production was observed, the results indicated that the isolate could form calcium oxalate crystals, produced urease, and was resistant to low pH. The isolate was sensitive to amphotericin but resistant to voriconazole and itraconazole. The features of this fungus that could help in its survival in the human gut are also discussed.
  15. Investigation of culturable human gut mycobiota from the segamat community in Johor, Malaysia
    Huët MAL, Wong LW, Goh CBS, Hussain MH, Muzahid NH, Dwiyanto J, et al.
    World J Microbiol Biotechnol, 2021 Jun 08;37(7):113.
    PMID: 34101035 DOI: 10.1007/s11274-021-03083-6
    Although several studies have already been carried out in investigating the general profile of the gut mycobiome across several countries, there has yet to be an officially established baseline of a healthy human gut mycobiome, to the best of our knowledge. Microbial composition within the gastrointestinal tract differ across individuals worldwide, and most human gut fungi studies concentrate specifically on individuals from developed countries or diseased cohorts. The present study is the first culture-dependent community study assessing the prevalence and diversity of gut fungi among different ethnic groups from South East Asia. Samples were obtained from a multi-ethnic semi-rural community from Segamat in southern Malaysia. Faecal samples were screened for culturable fungi and questionnaire data analysis was performed. Culturable fungi were present in 45% of the participants' stool samples. Ethnicity had an impact on fungal prevalence and density in stool samples. The prevalence of resistance to fluconazole, itraconazole, voriconazole and 5-fluorocytosine, from the Segamat community, were 14%, 14%, 11% and 7% respectively. It was found that Jakun individuals had lower levels of antifungal resistance irrespective of the drug tested, and male participants had more fluconazole resistant yeast in their stool samples. Two novel point mutations were identified in the ERG11 gene from one azole resistant Candida glabrata, suggesting a possible cause of the occurrence of antifungal resistant isolates in the participant's faecal sample.
  16. A three-dimensional (3D) printing approach to fabricate an isolation chip for high throughput in situ cultivation of environmental microbes
    Goh CBS, Goh CHP, Wong LW, Cheng WT, Yule CM, Ong KS, et al.
    Lab Chip, 2022 Jan 18;22(2):387-402.
    PMID: 34935836 DOI: 10.1039/d1lc00723h
    The full plethora of environmental bacteria is often poorly represented in vitro as the majority remain difficult, if not impossible, to culture under standard laboratory settings. These bacteria often require native conditions for the formation of cell masses that collectively have higher chances of survival. With that, a 3D-printed version of the isolation chip (iChip) was used to cultivate bacteria from a tropical peat swamp in situ prior to growth and maintenance in vitro. Briefly, plates made from either acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), or epoxy resin were tested in terms of their usability and durability under acidic conditions similar to those of peat matter. The epoxy resin plates were then found to be most optimal for the sampling conditions. Peat soil samples were collected from the base of a Koompassia malaccensis tree and reconstituted in molten 10% (wt/vol) tryptone soy agar (TSA) prior to inoculation. The iChips were subsequently assembled and buried in the site of origin. As a comparison, bacteria from the same soil sample were cultivated directly on TSA and incubated at 28 °C for two weeks. Thereafter, agar plugs from the iChip were transferred to TSA plates to allow microcolonies within each plug to grow. Each pure isolate from both cultivation approaches that grew was then pooled and extracted for total DNA prior to 16S rRNA gene amplification and sequencing via Illumina MiSeq. Taxonomic abundance comparison revealed that the bacterial taxa at the level of order were significantly different between the two approaches, particularly in the orders, Burkholderiales, Xanthomonodales, Enterobacteriales, and Actinomycetales (differences of 12.0, 7.1, 8.0, and 4.2%, respectively). This indicated that the 3D-printed iChips present a possible low-cost tool for the isolation of bacterial genera that may not be able to grow on media directly in vitro.
  17. Fulltext Electrochemical Preparation and Characterization of a Gold Nanoparticles Graphite Electrode: Application to Myricetin Antioxidant Analysis
    Ng KL, Lee SM, Khor SM, Tan GH
    Anal Sci, 2015;31(10):1075-81.
    PMID: 26460374 DOI: 10.2116/analsci.31.1075
    Graphite material is abundantly available from recyclable sources. It possesses a good electrical conductance property, which makes it an attractive material as a working electrode. However, due to a high activation overpotential it has limited applications as compared to other solid metal electrodes. In this present work, we obtained a graphite rod from a used battery, and carried out electrochemical improvements by electro-deposition with gold nanoparticles (AuNPs). The heterogeneous electron transfer rate and electron transfer resistance of the fabricated electrode were improved. The electrode overpotential has shown improvement by 50 mV, and the effective surface area has increased by 2 fold. To determine the practicability of the AuNPs/graphite electrode, we used the electrode in the analysis of myricetin. A square-wave voltammetry was used in the analysis, and the detection response increased by 2.5 fold, which suggested an improvement in the electrode sensitivity.
  18. Fulltext catena-Poly[[triphenyl-tin(IV)]-μ-2-[(3,5-di-tert-butyl-4-hydroxy-benz-yl)sulfan-yl]acetato-κO:O']
    Lee SM, Lo KM, Mohd Ali H, Robinson WT
    Acta Crystallogr Sect E Struct Rep Online, 2009;65(Pt 7):m808.
    PMID: 21582732 DOI: 10.1107/S1600536809023150
    The title compound, [Sn(C(6)H(5))(3)(C(17)H(25)O(3)S)](n), comprises two symmetry-independent five-coordinated triphenyl-tin mol-ecules which are linked by carboxyl-ate bridges into a polymeric chain. The Sn(IV) atom is in a distorted trans-C(3)SnO(2) trigonal-bipyramidal geometry. The presence of two bulky tert-butyl groups on the benzene ring prevents any hydrogen-bonding inter-actions involving the hydroxyl substituents.
  19. Fulltext Bis[4-(dimethyl-amino)pyridinium] tetra-bromidobis(4-methyl-phen-yl)stannate(IV)
    Lee SM, Lo KM, Mohd Ali H, Robinson WT
    Acta Crystallogr Sect E Struct Rep Online, 2009;65(Pt 9):m1040.
    PMID: 21577403 DOI: 10.1107/S1600536809030323
    In the title compound, (C(7)H(11)N(2))(2)[SnBr(4)(C(7)H(7))(2)], the tetra-bromidobis(4-methyl-phen-yl)stannate(IV) anion possesses a centre of inversion located at the Sn(IV) atom. In the crystal structure, two inversion-related cations are linked to the anion via weak N-H⋯Br hydrogen bonds.
  20. Fulltext Bis[4-(dimethyl-amino)pyridinium] tetra-bromidobis(4-chloro-phen-yl)stannate(IV)-4-bromo-chloro-benzene (1/1)
    Lee SM, Lo KM, Mohd Ali H, Robinson WT
    Acta Crystallogr Sect E Struct Rep Online, 2009;65(Pt 9):m1039.
    PMID: 21577402 DOI: 10.1107/S1600536809030232
    In the title compound, (C(7)H(11)N(2))(2)[SnBr(4)(C(6)H(4)Cl)(2)]·C(6)H(4)BrCl, the Sn(IV) atom in the tetra-bromidobis(4-chloro-phen-yl)stannate(IV) anion lies on a centre of inversion. The distances between the 4-(dimethyl-amino)pyridinium N atom and the Br atoms of the anion are 3.450 (2) and 3.452 (2) Å, suggesting weak hydrogen bonding. The 4-bromo-chloro-benzene solvent mol-ecule, which is a bromination by-product from the reaction, is disordered about a twofold rotation axis with approximately equal occupancy.
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