bluuebunny/crossref_metadata_2025_split huggingface dataset:
Arsenocholine from anaerobic decomposition of a trimethylarsonioriboside
Authors: Francesconi Kevin A , Edmonds John S , Stick Robert V 
Published: January 2005

AbstractWhen subjected to conditions supporting anaerobic microbial activity, the naturally occurring trimethylarsonioriboside, (2′S)‐2′‐hydroxy‐3′‐(sulpho‐oxy)propyl 5‐deoxy‐5‐trimethylarsonio‐β‐D‐riboside 4 was converted to arsenocholine 5 in virtually quantitative yield.
Selective determination of trace arsenic and antimony species in natural waters by gas chromatography with a photoionization detector
Authors: Yamamoto Masahiro , Tanaka Shigeru , Hashimoto Yoshikazu 
Published: January 2005

AbstractTraces amounts of arsenic and antimony in water samples were determined by gas chromatography with a photoionization detector after liquidnitrogen cold trapping of their hydrides.The sample solution was treated with sodium hydroborate (NaBH4) under weak‐acid conditions for arsenic(III) and antimony(III) determination, and under strong‐acid conditions for arsenic(III+V) and antimony(III+V) determination.Large amounts of carbon dioxide (CO2) and water vapor obscured determination of arsine and stibine. Better separation from interference could be achieved by removing CO2 and water vapor in two tubes containing sodium hydroxide pellets and calcium chloride, respectively.The detection limits of this method were 1.8 ng dm−3 for arsenic and 9.4 ng dm−3 for antimony in the case of 100‐cm3 sample volumes. Therefore, it is suitable for determination of trace arsenic and antimony in natural waters.
Effects of arsenic on the organic component of the alga Dunaliella salina
Authors: Yamaoka Yukiho , Takimura Osamu , Fuse Hiroyuki , Kamimura Kazuo 
Published: January 2005

AbstractThe unicellular marine alga, Dunaliella salina 19/30 was grown in seawater containing an inorganic arsenic concentration (Na2HAsO4) up to 2000 mg dm−3. The cells survived even at 5000 mg dm−3. The arsenic concentration of the cells increased with an increase of the surrounding arsenic concentration. Arsenic in D. salina was also greatly affected by addition of phosphorus. The arsenic‐tolerance behavior of D. salina seemed to suggest that the algae have a function to prevent accumulation of inorganic arsenic by increasing the β‐carotene, fatty‐acid (C18:1, C18:3) and water‐extractable carbohydrate content in the cells. Arsenic accumulation also rose steadily with an increase in the nitrogen concentration in the medium.
Effect of cadmium on the accumulation of arsenic in a marine green alga, Dunaliellasp.
Authors: Takimura Osamu , Fuse Hiroyuki , Yamaoka Yukiho 
Published: January 2005

AbstractTo investigate the effect of cadmium on the accumulation of arsenic by Dunaliella sp., the arsenic accumulated in the alga was determined as a function of time for coexistence of the algae with arsenic and cadmium, with batch methodology. Growth of Dunaliella sp. was affected by addition of arsenic (Na2HAsO4.7H2O) and cadmium (CdCl.2.5H2O). Growth inhibition of Dunaliella sp. was accelerated by coexistence of arsenic and cadmium. The content of arsenic in Dunaliella sp. became a maximum at 15 h after exposure. The arsenic content in the cells was influenced by addition of cadmium to the solution; the arsenic content in the alga derived from growth in a 10 mg As dm −3 solution decreased from 2.7 mg g−1 in the absence of cadmium to 0.35 mg g−1 for the addition of 100 mg Cd dm−3. Dunaliella sp. accumulated cadmium in large quantities but, in conditions of coexistence with arsenic and cadmium, the cadmium content in cells decreased with an increase in the concentration of arsenic in the growth medium Cadmium accumulation by Dunaliella sp. was observed in dead cells although arsenic accumulation was not observed. About 85% of arsenic in the cells was in the water‐soluble fraction. On the other hand, about 42% of cadmium in the cells was in the water‐soluble fraction, and about 55% was in a fraction soluble in cold trichloroacetic acid.
The association mode of arsenic accumulated in the freshwater alga Chlorella vulgaris
Authors: Maeda Shigeru , Arima Hiroshi , Ohki Akira , Naka Kensuke 
Published: January 2005

AbstractArsenic accumulated in living Chlorella vulgaris cells was solvent‐fractionated with chloroform/methanol (2:1), and the fractions were analyzed for arsenic. A large part of the accumulated arsenic was localized in the extract residues.The extract residue from the same extraction of C. vulgaris, which had been, however, cultured in any arsenic‐free Detmer medium (MD), adsorbed arsenic physico‐chemically at a concentration of 1.1 mg As g−1 dry weight.Arsenic was found to be combined with protein with molecular weight around 3000 in the arsenicaccumulated living cells. The arsenic‐bound protein was analyzed for amino acids. The experimental results showed that no metallothionein‐like protein was inductively biosynthesized in C. vulgaris on the exposure to arsenic.
Metabolism of methylated arsenic compounds by arsenic‐resistant bacteria (Klebsiella oxytoca and Xanthomonas sp.)
Authors: Maeda Shigeru , Ohki Akira , Miyahara Kuniaki , Naka Kensuke , Higashi Shiro 
Published: January 2005

AbstractTwo bacteria exhibiting resistance to toxic arsenic were isolated. These had been contaminated with arsenic in a Chlorella sp. culture medium containing arsenic. The two bacteria were identified as Klebsiella oxytoca and Xanthomonas sp., and grew well in a peptone medium at neutral pH at 30°C, reaching the stationary phase in ca 100h and 70h, respectively. The growth of the bacteria was not affected by arsenic(V) concentrations in the medium as high as 1000mg dm−3. The bacteria bioaccumulated arsenic, a part of the arsenic being methylated. The bioaccumulation exhibited its peak around the turing point from the log phase to the stationary phase. The relative content of methylated arsenic in the excrement was greater than that in the bacterial cells. Adaptation treatment of inorganic arsenic caused an increase in the bioaccumulation of inorganic arsenic by K. oxytoca. Such a situation was not observed in the case of Xanthomonas sp. The bacteria also bioaccumulated methylated arsenic compounds, and demethylation of these species was observed. When the bacteria were killed by ethanol, arsenic was not taken up by the cells.
The activation of tertiary amines by osmium cluster complexes: Further studies of the reaction of Os3(CO)10(NCMe)2 with triethylamine
Authors: Adams Richard D , Tanner James T 
Published: January 2005

AbstractThe reactions of Os3(CO)12 and Os3(CO)10(NCMe)2 with NEt3 have been reinvestigated. Two new products, Os3(CO)10(μ‐CH2C(H)NEt2)(μ‐H)) (2) and Os3(CO)10(syn‐μ‐η1‐CHCHNEt2)(μ‐H) (3) were obtained in low yields, 4% and 7%, in addition to the previously reported compound Os3(CO)10(anti‐μ‐η1‐CHCHNEt2(μ‐H) (1) (20% yield) when the reaction was conducted at 25°C using Os3(CO)10(NCMe)2. Compounds 2 and 3 were characterized by IR, 1H NMR and single‐crystal X‐ray diffraction analyses. Compound 2 contains a bridging methyl‐metallated N‐ethylimine ligand formed by the cleavage of one ethyl group from the NEt3. Compound 3 is an isomer of 1 in which the bridging ligand has a syn conformation with respect to the cluster as compared with the anti conformation in 1. Compound 3 slowly isomerizes to 1. Compound 3 is de‐carbonylated by exposure to UV radiation and is transformed to the new compound Os3(CO)9(μ3‐CC(H)NEt2)(μ‐H)2 (4) (58% yield) by an additional CH activation to form a triply bridging η1‐diethylaminovinylidene ligand. Compound 4 isomerizes to the compound Os3(CO)9(μ3‐HCCNEt2)(μ‐H)2 (5) (70% yield) at 68°C. The latter contains a triply briding ynamine ligand which exhibits structural and reactivity features that are characteristic of a carbene ligand at the amine‐substituted carbon atom. Crystal data: for 2, space group = P21/c, a = 9.236(2) Å, b = 12.469(2) Å, c = 18.107(3) Å, β = 104.67(1)°, Z = 4, 2518 reflections, R = 0.031; for 3, space group = P21/m, a = 7.644(1) Å, b = 12.706(2) Å, c = 11.912(2) Å, β = 108.02(1)°, Z = 2, 1295 reflections, R = 0.030; for 4, space group = P21/n, a = 10.233(2) Å, b = 14.834(4) Å, c = 14.538(2) Å, β = 99.88(2)°, Z = 4, 2403 reflections, R = 0.036.
Metal alkoxides and β‐diketonates as precursors for oxide and non‐oxide thin films
Authors: Hubert‐Pfalzgraf L G 
Published: January 2005

AbstractSingle‐components or multicomponent oxide thin films are of interest for electronic and opto‐electronic devices, optical applications, catalysis, corrosion protection etc. Their preparation by chemical routes is based on the hydrolytic (sol‐gel process) or pyrolytic (MOCVD) conversion of precursors. Derivatives having MO bonds, namely metal alkoxides, carboxylates or β‐diketonates, are the most common sources of metal oxides. The properties of alkoxides are appropriate for sol‐gel as well as MOCVD applications, whilst the limited hydrolytic susceptibility but good volatility of β‐diketonates is most convenient for MOCVD purposes. The low temperature and flexibility of sol‐gel routes, and the presence of residual OH groups in the final films, are favorable for the encapsulation of organic or organometallic derivatives, the anchoring of enzymes and in general for the development of functional and composite coatings. The facile formation of heterometallic alkoxides is also attractive for the development of coatings based on multimetallic formulations. MOCVD is favorable for the buildup of heterostructures and epitaxial layers. Although metal alkoxides and β‐diketonates are usually oxide precursors, nitride or sulfide films can be obtained by reacting with the appropriate reagents. Fluorinated ligands enhance volatility but often result in the formation of metal fluorides.
Preparation of copper‐indium sulfide thin films by single‐source OMCVD: Mass‐spectral investigation of decomposition path of the organometallic sources
Authors: Nomura Ryǒki , Seki Yasuharu , Konishi Kazuhisa , Matsuda Haruo 
Published: January 2005

AbstractIn order to prepare high‐quality CuInS2 thin films vapor phase decomposition patterns of three copper‐indium binuclear complexes,
equation image
and
equation image
as candidates for source materials were investigated using EI MS. The complex 1c showed series of intensive peaks due to the fragmentation of M+. For 1a, only a fragmentation pattern starting from BuIn(S2CNBu2)2 was detectable. This should suggest that 1a decomposed into BuIn(S2CNBu2)2 and copper sulfide before vaporization. In addition an ambiguous feature could be observed for 1b, viz. two fragmentation paths. Consequently, we judge that 1c is a suitable source complex to prepare CuInS2 thin films via a single‐source OMCVD process. Thus chalcopyrite CuIns2 thin films were successfully prepared via single‐source OMCVD using 1c as a source complex, with Tsubstrate400°C, Tsource80°C, base pressure 0.7 Torr and carrier (nitrogen) flow rate 0.8 L min−1. Fragmentation of two copper dithiocarbmates, Cu(S2CNBu2)2 and Cu[S2CN(i‐Pr)2]2, and two butylindium thiolates, Bu2InS(i‐Pr) and BuIn[S(i‐Pr)]2, as components of 1 is additionally discussed.
Low‐temperature isospecific polymerization of propylene catalyzed by alkylzirconocene‐type ‘cations’
Authors: Tsai Woei‐Min , Rausch Marvin D , Chien James C W 
Published: January 2005

AbstractThe rac‐ethylenebis(indenyl)methylzirconium ‘cation’ (1), generated from rac‐Et(Ind)2ZrMe2 and Ph3CB(C6F5)4, has recently been shown to be exceedingly active and stereoselective in propylene polymerization. The ethyl analog (2) can be produced by an alternate, efficient route involving a reaction between rac‐Et(Ind)2ZrCl2 and AlEt3 (TEA), followed by addition of Ph3CB(C6F5)4. The use of excess AlEt3 serves both to alkylate the zirconium complex as well as to scavenge the system. The propylene polymerization activity of the ‘cation’ 2 is about 7000 times greater than the activity of rac‐Et(Ind)2ZrCl2/methylaluminoxane (MAO) at Tp=−20°C. The related catalyst system rac‐Me2Si(Ind)2ZrCl2/TEA/Ph3CB(C6F5)4 (3) was found to produce 98.3% i‐PP with Tm 156.3°C and an activity of 1.8 × 109 g PP {(mol Zr) [C3H6]h}−1.
Transformations of mercury species in the presence of Elbe river bacteria
Authors: Ebinghaus R , Wilken R D 
Published: January 2005

AbstractThe influence of Elbe river bacteria isolated from suspended particulate matter (SPM) on dynamic species transformation of mercury was investigated. Experiments were carried out in the presence of bacteria (batch cultures) and in sterile tapwater as a control. For the methylation of inorganic mercury ions by bacteria several cofactors are under discussion. In this work, methylcobalamin, methyl iodide and S‐adenosylmethionine were tested as biogenic methyl donors and trimethyl‐lead chloride, trimethyltin chloride and dimethylarsenic acid as abiotic methyl donors. Transmethylation reactions as examples of abiotic methyl transfers have higher effectiveness in the formation of methylmercury (CH3Hg+) than methylation with biogenic compounds. This result was observed in batch cultures as well as in sterile water. SPM‐bacteria inhibit methyl transfer to mercury(II) ions. This is not only due to passive adsorption processes of mercury(II) to bacterial cell walls; methylmercury is also decomposed very rapidly by SPM‐bacteria and is immobilized as mercury(II) by the cells.
Dibutyltin‐3‐hydroxyflavone bromide: A fluorescent inhibitor of F1F0‐ATPase
Authors: Usta Julnar , Griffiths David E 
Published: January 2005

AbstractDibutyltin‐3‐hydroxyflavone bromide [Bu2SnBr‐(of)] is a fluorescent inhibitor (excitation max, 395 nm; emission max., 450 nm) of mitochondrial F1F0–ATPase which does not inhibit F1–ATPase. Bu2SnBr(of) binding to mitochondria and submitochondrial particles results in a 10‐fold fluorescence enhancement which correlates with the amount of F1F0–ATPase in the inner membrane. Enhancement is not affected by respiratory‐chain substrates, ATP, uncoupling agents, ionophores or respiratory‐chain inhibitors. It is reversed by tributyltin chloride (Bu3SnCl), indicating competition for a common triorganotin‐binding site on the F0 segment of F1F0–ATPase. Enhancement is not reversed by dialkyltins, monoalkyltins, tributyl‐lead acetate, efrapeptin or oligomycin. Bu2SnBr(of) is thus a new class of fluorescent probe of the F0 segment of F1F0–ATPase which titrates F0.
Synthesis of cobaltocenium salts for use as redox labels and their incorporation into Nafion films
Authors: Degrand Chantal , Limoges Benoit , Gautier Arnaud , Blankespoor Ronald L. 
Published: January 2005

AbstractA cobaltocenium label was covalently attached to two antidepressants, nortriptyline and desipramine, via an amide linkage, and also to the hydrazine derivative of the biologically important compound biotin (vitamin H), again via an amide linkage. Analytically pure samples of these new cobaltocenium salts could be obtained by chromatography on silica gel followed by elution with aqueous acetone solutions containing sodium chloride (NaCl). These positively charged cobaltocenium ions preconcentrate in a polyanionic Nafion film coated on a glassy carbon surface, albeit at different concentration levels. One factor which seems to influence the amount of cobaltocenium ion that enters the film is polarity since the cobaltocenium ion containing the rather polar biotin preconcentrates at the lowest level in the relatively hydrophobic Nafion. Square‐wave voltammograms of Nafion films containing these cobaltocenium cations exhibit a one‐electron, reversible, reduction wave at approximately −1.1 V (vs Ag/AgCl) with peak currents that are sufficiently large to permit detection of 10−8 M quantities of these substances in the bulk solution.
Hydrosilylation of alkenes catalysed by rhodium complexes immobilized on silica via a pyridine group
Authors: Čapka Martin , Czakoová Marie , Schubert Ulrich 
Published: January 2005

Abstract2‐(2‐Trimethoxysilylethyl)pyridine, together with 3‐methcryloxypropyltrimethoxysilane, was used to prepare a series of rhodium carbonyl complexes bound to silica via a pyridine group. The rhodium complex Rh2(CO)4Cl2 (Rh2) was used as the starting compound, and the immobilized complexes were prepared by four different routes which yielded both surface‐bonded complexes and complexes bonded within the silicate matrix. These complexes were efficient catalysts of hydrosilylation of octene by triethxysilane. All the immobilized complexes were more than their homogeneous analogues and some could be re‐used.
Si/C/F/H materials from laser‐explosive decomposition of fluoromethylsilanes
Authors: Pola J. , Bastl Z. , Tläskal J. , Beckers H. , BÜRger H. , Moritz P. , Weiss P. , Sigrist M. 
Published: January 2005

AbstractSolid Si/C/H/F materials laser‐deposited from gaseous fluoro‐methylsilanes are examined by XPS, SEM, IR and Raman spectroscopy and revealed to be a blend of silicon‐carbon‐based frameworks, possessing some Si‐H and C‐H bonds, and carbon whose modification is dependent on the structure of the parent fluoromethylsilane. Their properties are affected by contact with the atmosphere: although incorporation of oxygen into silicon‐carbon frameworks is a very fast process, the dramatically improved adhesion to aluminium requires long exposure periods.
Interaction of triorganotin compounds with chesapeake bay sediments and benthos
Authors: May Leopold , Whalen Deborah , Eng George 
Published: January 2005

AbstractTriorganotin compounds can interact with various segments of natural water systems. In sediments, for example, these compounds can undergo speciation, and can also become injurious to benthos. The interaction of tributyltin (TBT) and triphenyltin (TPT) compounds with sediments have been studied using extraction techniques in addition to directly observing these compounds in sediments using Mössbauer spectroscopy. The effect of these compounds on benthos has also been examined. The results of these studies are reviewed with particular regard to studies on sediments from the Chesapeake Bay, USA.
Arsenic metabolism in a freshwater food chain: Blue–green alga (Nostoc sp.)→ shrimp (Neocaridina denticulata)→ carp (Cyprinus carpio)
Authors: Maeda Shigeru , Mawatari Kayoko , Ohki Akira , Naka Kensuke 
Published: January 2005

AbstractBioaccumulation and biomethylation of inorganic arsenic were investigated in a three‐step fresh‐water food chain consisting of an autotroph (blue‐ green alga: Nostoc sp.), a herbivore (shrimp: Neocaridina denticulata) and a carnivore (carp: Cyprinus carpio). The autotroph, herbivore and carnivore survived in arsenic‐containing water below 1000, 2 and 60 mg As(V) dm−3, respectively. Bioaccumulation of arsenate by Nostoc sp. was decreased with an increase in the nitrogen concentration of the medium. Arsenic(V) was accumulated from the water phase and part‐methylated by the carp, as well as by the algae and shrimp. Arsenic was mostly accumulated in the gut of the carp. The predominant arsenical in the guts was the monomethylarsenic species.Arsenic accumulation via food in the above three‐step food chain decreased by one order of magnitude and the relative concentration of methylated arsenic to the total arsenic accumulated increased successively with an elevation in the trophic level. When arsenicals were transferred via the food chain, no monomethylarsenic, or only a trace amount, was detected in the three organisms. Dimethylarsenic in the alga, both dimethyl‐ and trimethyl‐arsenic in shrimp, and trimethyl‐arsenic in carp, were the predominant methylated arsenic species, respectively.
Insecticidal effects of organotin(IV) compounds on Plutella xylostella (Linnaeus) larvae I: Topical application toxicity and antifeedant effect
Authors: Ahmad Nazni W , Mohd Sofian‐Azirun , Balabaskaran S , Das V G Kumar 
Published: January 2005

AbstractStructure–activity relationship studies were conducted with early fourth‐instar larvae of a highly resistant strain of the diamondback moth, Plutella xylostella (Linnaeus) on (1) toxicity by topical appliction of 43 organotin compounds, and (2) the antifeedant effect of a selected number (17) of these compounds on treated Brassica chinensis (Chinese cabbage) leaves.The toxicity data revealed that the triorganotins (R3SnX) were, without exception, more toxic than the commercial sample of malathion (84% active ingredient) used in the tests. Among the diorganotins, phenylcyclopentyltin oxide proved to be as active as malathion. Within the triorganotin series, the tricyclohexyltins were generally more toxic than the triphenyltins, the most active tricyclohexyltin compound being (c‐C6H11)3Sn(2‐pyridinethiolato N‐oxide) (LC50 0.03 μg μl−1), which was almost 500‐fold more active than malathion. The most active compound in the triphenyltin class was O, S‐bis(triphenyltin)mercaptoacetate (LC50 0.30 μg μl−1). Variations in the anionic X group resulted only in marginal changes in activity in the (c‐C6H11)3Sn series, but significant changes in activity were obtained with the Ph3Sn compounds, especially the ring‐substituted phenoxyacetates, (4‐ZC6H4)OCH2(O)COSnPh3. In the mixed triorganotin compounds an increase in activity was observed when one of the phenyl groups in Ph3SnOH was replaced by the p‐chlorophenyl group.In the antifeedant tests, the tricyclohexyltins were found to be generally more effective than the triphenyltins. In most cases, antifeedant activity paralleled the toxicity by topical application trends in the (c‐C6H11)3Sn series, but in the Ph3Sn series an inverse trend was observed. The diorganotin compound (c‐C5H9)PhSnO exerted a relatively pronounced antifeedant activity which was comparable with that of a number of triphenyltin derivatives.It was established from histological studies of the mid‐gut cross‐sections of the treated larvae that, in most cases, the organotins affected the columnar cells physiologically; an exception was noted for Ph3SnOC(O)C6H4COOH‐4 which, like malathion, caused severe morphological damage to the cell membrane.
Synthesis, spectroscopic characterization and fungicidal activity of triphenyltin derivatives ofN,N‐dimethylglycine: Crystal structure of [dimethyl(carboxylatomethyl)ammonium]‐chlorotriphenylstannate
Authors: Khoo Lian Ee , Goh Ngoh Khang , Otieno Monicah A. , Lucero Rosemarie A. , Eng George , Luo Boa Sheng , Mak Thomas C. W. 
Published: January 2005

AbstractThe new triorganotin complexes formulated as Me2HNCH2COO · Ph3SnX, X = Cl, NCS were prepared and spectroscopically characterized, and their fungicidal properties againstCeratocystis ulmiwere determined. An X‐ray structure for [dimethyl(carboxylatomethyl)ammonium] chlorotriphenylstannate is also reported.
Solubilization of arsenic from gallium arsenide using aqueous suspensions of organic halides
Authors: Craig Peter J. , Laurie Stuart H. , McDonagh Reman 
Published: January 2005

AbstractThe solubilization of arsenic in solid gallium arsenide by aqueous solutions/suspensions of organic halides is described. Although arsenic is removed from gallium arsenide surfaces, excess quantities of gallium are not found in the solution. The abilities of the organic halide to solubilize arsenic decreases as follows:
C2H5Br> CH3I> 2‐C3H7I> 1‐C3H7I> 2‐C4H9Br> CH2CHCH2I> 2‐C3H7Br≃ 1‐C4H9Br.The results correlate with a combination of organic halide solubility, bond enthalpy and carbonium ion stability factors. Other parameters investigated using gallium arsenide and iodomethane include concentration, physical state of the arsenide, pH, role of oxygen and role of light.