bluuebunny/crossref_metadata_2025 huggingface dataset:
Methylated antimony(V) compounds: Synthesis, hydride generation properties and implications for aquatic speciation
Authors: Dodd Matthew , Grundy Stephen L , Reimer Kenneth J , Cullen William R
Published: January 2005

Reports in the literature that the compounds MeSb(O)(OH)2 and Me2Sb(O)(OH) are present in marine and fresh‐waters need to be re‐examined. The results of several synthetic strategies suggest that these methylantimony(V) compounds are either environmentally inaccessible or polymeric in nature. Pure samples of various di‐ and tri‐ methylated antimony(V) species were prepared and found to undergo molecular rearrangement reactions when subjected to hydride generation procedures typically used for aquatic speciation.
Occurrence of methylated tin and dimethyl mercury compounds in a mangrove core from Sepetiba Bay, Brazil
Authors: Quevauviller P , Donard O F X , Wasserman J C , Martin F M , Schneider J
Published: January 2005

Analyses of organotin and organic mercury compounds have been performed in a sediment core from Sepetiba Bay, Brazil, in order to investigate possible methylation pathways in a mangrove environment. The results have revealed that the physico‐chemical conditions existing in this type of environment (high organic inputs, anaerobic conditions, microbial activity, etc.) account for high methyltin concentrations (mono‐, di‐ and trimethyltin) in the sediments, which are dependent upon the total load of metal released (e.g. from anthropogenic sources). Furthermore, the presence of dimethylmercury and not monomethylmercury in the samples demonstrated a new pathway of transformation of mercury in the environment: this compound, thought to be unstable in sediment, is assumed to be stabilized by a conjunction of factors, such as high sulphide levels, anoxic conditions and constant inputs of methane into the medium.
Arsenocholine from anaerobic decomposition of a trimethylarsonioriboside
Authors: Francesconi Kevin A , Edmonds John S , Stick Robert V
Published: January 2005

When 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

Traces 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

The 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

To 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

Arsenic 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

Two 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

The 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

Single‐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

In 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

The 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

The 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

Dibutyltin‐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

A 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

2‐(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

Solid 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

Triorganotin 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

Bioaccumulation 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

Structure–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

The 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

The 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.
Interpretation of inorganic arsenic metabolism in humans in the light of observations made in vitro and in vivo in the rat
Authors: Buchet J. P. , Lauwerys R.
Published: January 2005

The toxicity of inorganic trivalent arsenic for living organisms is reduced by in vivo methylation of the element. In man, this biotransformation leads to the synthesis of monomethylarsonic (MMA) and dimethylarsinic (DMA) acids, which are efficiently eliminated in urine along with the unchanged form (Asi). In order to document the methylation process in humans, the kinetics of Asi, MMA and DMA elimination were studied in volunteers given a single dose of one of these three arsenicals or repeated doses of Asi. The arsenic methylation efficiency was also assessed in subjects acutely intoxicated with arsenic trioxide (As2O3) and in patients with liver diseases. Several observations in humans can be explained by the properties of the enzymic systems involved in the methylation process which we have characterized in vitro and in vivo in rats as follows: (1) production of Asi metabolites is catalyzed by an enzymic system whose activity is highest in liver cytosol; (2) different enzymic activities, using the same methyl group donor (S‐adenosylmethionine), lead to the production of mono‐ and di‐methylated derivatives which are excreted in urine as MMA and DMA; (3) dimethylating activity is highly sensitive to inhibition by excess of inorganic arsenic; (4) reduced glutathione concentration in liver moderates the arsenic methylation process through several mechanisms, e.g. stimulation of the first methylation reaction leading to MMA, facilitation of Asi uptake by hepatocytes, stimulation of the biliary excretion of the element, reduction of pentavalent forms before methylation, and protection of a reducing environment in the cells necessary to maintain the activity of the enzymic systems.
Degradation of a tetramethylarsonium salt by microorganisms occurring in sediments and suspended substances under both aerobic and anaerobic conditions
Authors: Hanaoka Keńichi , Araki Noriyuki , Tagawa Shoji , Kaise Toshikazu
Published: January 2005

Microbial degradation of a tetramethylarsonium salt during incubation at 25°C was investigated under both aerobic and anaerobic conditions. Two media (1/5 ZoBell 2216E and inorganic salt medium), added with the sediments or suspended substances as the sources of the microorganisms, were used. Degradation of the tetramethylarsonium salt occurred only in the ZoBell medium: under anaerobic conditions, trimethylarsine oxide and dimethylarsinic acid were derived with the sediments, and dimethylarsinic acid with the suspended substances, the salt degrading more rapidly with the former than with the latter. Small amounts of two metabolites, trimethylarsine oxide and inorganic arsenic(V), was also derived in the aerobically incubated ZoBell medium added with the suspended substances. This result means that the tetramethylarsonium salt is degraded to inorganic arsenic, which is the starting material for arsenic circulation in marine ecosystems, via trimethylarsine oxide and dimethylarsinic acid.
Detection of arsenobetaine in human blood
Authors: Shibata Yasuyuki , Yoshinaga Jun , Morita Masatoshi
Published: January 2005

Arsenobetaine was detected and quantified unambiguously in human plasma, serum and red blood cells by the combination of HPLC with ICP MS. Three different column conditions, i.e. two ionpair chromatographies for anionic (LC‐1) and cationic (LC‐2) compounds and gel‐permeation chromatography (LC‐3), were employed to confirm the assignment. Arsenobetaine was detected in every sample as a major component of the water‐soluble arsenic compounds, with an increasing concentration in plasma < serum < blood cell fractions. It was the sole detectable arsenic compound in LC‐1 and LC‐2, while a broad peak corresponding to high‐molecular‐weight compounds was identified in addition to arsenobetaine in LC‐3.
Critical review of analytical methods for determination of inorganic mercury and methylmercury compounds
Authors: Puk Richard , Weber James H.
Published: January 2005

This review describes determinations of mercury compounds under three categories: total mercury; separate determinations of inorganic mercury(II) and organomercury compounds by selective reduction; and speciation of inorganic mercury(II), monomethylmercury cation, and dimethylmercury. Topics described for each category include sample treatment, separation, detection, and limit of detection. Finally, we note that most methods would not detect dimethylmercury if it were present.
Catalysis of hydrosilylation: Part XXIV. H2PtCl6 in cyclohexanone as hydrosilylation catalyst—what is the active species in this catalytic system?
Authors: Guliński J. , Kłosin J. , Marciniec B.
Published: January 2005

A cyclohexanone solution of H2PtCl6 was examined to find the catalytic species responsible for the hydrosilylation of the olefinic C=C bond. Similarly to other H2PtCl6–solvent systems (e.g. Speier's and Karstedt's catalysts), the real catalyst appeared to be colloidal platinum formed in situ by stepwise reduction [Pt(IV)→Pt(O)] and dechlorination of the platinum precursor. The role of cyclohexanone seems to be to form sufficiently stable platinum complexes to avoid rapid platinum precipitation and aggregation. The studies of H2PtCl6–solvent systems are of practical importance since these compounds are widely used catalyst precursors for hydrosilylation on an industrial scale.
Stereoselective reduction of α‐substituted β‐keto esters by hydrostannane/organotin triflate
Authors: Sato Tsuneo , Otera Junzo
Published: January 2005

Stereoselective reduction of α‐substituted β‐keto esters is achieved by the combined use of hydrostannane/organotin triflate. syn‐Aldols are obtained with more than 90% selectivities.
Validation of the analysis of organotin compounds in biological tissues using alkylation and gas chromatography
Authors: Stäb Joan A. , Th. Brinkman Udo A. , Cofino Wim P.
Published: January 2005

Several critical steps in the analytical procedure for organotin compounds in the environment are identified in this paper and solutions are suggested. In particular, an improved procedure for quenching excess Grignard reagent is described. After insight into the nature of losses was obtained, the use of internal standards made it possible to reduce further the method variability. The systematic optimization of the analytical procedure resulted in a well investigated and robust method for analysis of organotin compounds in zebra mussel samples. Organotin compounds (OTs) which enter the environment as a result of their use as biocides and their degradation products are regularly found in environmental samples. Many different analytical techniques are currently being used,1 but little is known about their accuracy and precision.
Optimization of method for speciation of mercury(II), monomethylmercury cation, dimethylmercury and diethylmercury by hydride generation
Authors: Weber James H. , Puk Richard
Published: January 2005

This paper describes optimization details of an analytical method development of a hydride‐generation procedure for speciation of mercury(II), monomethylmercury cation, dimethylmercury, and diethylmercury using a heated quartz furnace with an atomic absorption spectrophotometer (AAS) as a detector. Typically a new analytical method is developed in steps such as the following: (1) determining analytes individually to confirm retention times and the lack of decomposition during the procedure; (2) comparing peak areas of all analytes as a function of quartz furnace temperature to optimize atomization for AAS detection; (3) conducting factorial experiments to determine which hydride‐generation reaction conditions are important in maximizing peak areas and which conditions interact with each other; (4) using the simplex optimization method to give final optimization of reaction conditions. These steps result in conditions that maximize optimized peak areas for analytes while minimizing experimental error.
The structure of very thin gold layers produced by metalorganic chemical vapour deposition
Authors: Allen D. W. , Haigh J.
Published: January 2005

Gold layers have been deposited from methyl(triethylphosphine)gold(I) by metalorganic chemical vapour deposition (MOCVD) and their structure and composition examined. At two deposition temperatures the layers have an underlying structure which is fine‐grained in the case of the 500°C layer and therefore of interest for thin‐layer device structures. Impurity levels are low in this layer.
Diorganotin(IV) and triorganotin(IV) derivatives of diphenic acid
Authors: Sandhu G. K. , Hundal R.
Published: January 2005

The diorganotin(IV) and triorganotin(IV) derivatives R2SnA (R = Me, n‐Pr, n‐Bu, n‐Oct) and (R3Sn)2A [R = Me, Ph, cyclohexyl (Cyh); A = an anion of diphenic acid] have been prepared and characterized by elemental analysis, IR, 1H and 13C NMR spectroscopies. Tetrahedral tin forms a part of a diphenate cyclic ring in the diorganotin complexes with unidentate carboxylates, which have further been used for the synthesis of cyclic acid anhydrides. The soluble dinuclear triorganotin complexes (Me, Ph) possess symmetrically bonded carboxylates while the less soluble compound (Cyh3Sn)2A has two asymmetrically bonded carboxylates. All have a trigonal bipyramidal structure with R3Sn units remote from each other.
Synthesis and characterization of phenoxarsin‐10‐yl 2‐R2N‐cyclopent‐1‐ene‐1‐carbodithioate (R = H, C2H5, cyclo‐C6H11CH2) and the crystal and molecular structure of the 2‐amino (R = H) derivative
Authors: Cea‐Olivares Raymundo , Toscano Rubén‐Alfredo , Estrada Mirna , Silvestru Cristian , García Patricia García y , López‐Cardoso Marcela , Blass‐Amador Georgina
Published: January 2005

Phenoxarsin‐10‐yl derivatives of 2‐amino‐cyclopent‐1‐ene‐1‐carbodithioic acid, (ACDA), and its N‐alkyl derivativesO(C6H4)2 AsS2C—C5H6— NHR‐2 (R = H, CH2CH3, CH2C6H11,), have been prepared by reacting O(C6H4)2AsCI with the corresponding ACDA 1,1‐dithioic acid. The compounds were obtained by stirring stoichiometric amounts of the reagents in ethanol, over 24 h, at room temperature. The scale of the preparations were in the order of 2 mmol and the yields of the compounds ca 75%. The reactions were carried out in absolute ethanol. The compounds were characterized by IR, mass and NMR (1H, 13C) spectroscopy. The molecular structure of O(C6H4)2AsS2C—C5H6—NH2‐2 was determined using X‐ray diffractometry, achieving an R‐value of 6.3%; this compound is monomeric and contains an asymmetric monometallic biconnective 1,1‐dithiolato ligand [As—S(1) 2.272(2) å, As … S(2) 3.125(2) å]. An intramolecular hydrogen bond is established between one hydrogen atom of the NH2 group and the sulfur [S(2)] atom involved in the secondary interaction to arsenic. The dihedral angle (150.3(3)°) of the phenoxarsine moiety is practically unaffected by substitution of chlorine on arsenic by the carbodithioato ligand.
Synthesis of 1‐triphenylgermylpropiono‐4‐substituted semicarbazides, thiosemicarbazides and their heterocyclic derivatives
Authors: Ruyu Chen , Fengfu Li
Published: January 2005

Twenty‐one new organogermanium compounds with the formulae Ph3GeCHR1CH2CONHNHC(X)NHR2 (1) (R1=H, Ph; = Ph, p‐CH3Ph, O‐CH3Ph, p‐ClPh, COPh, X = S, O) and magnified image (R1 = H, Ph; R2 = Ph, p‐CH3Ph, o‐CH3Ph, p‐ClPh; X=S, O) were synthesized and characterized by elemental analysis, 1H NMR, IR, MS and X‐ray diffraction techniques. Compounds l were prepared by the reactions of Ph3GeCHR1CH2CONHNH2 with R2NCX in chloroform in 77‐94% yields, and 2 were obtained by refluxing l with sodium hydroxide (8%) with yields of 55‐94%.
Developmental aspects of passive and active avoidance learning in rats
Authors: Riccio David C. , Rohrbaugh Michael , Hodges Louis A.
Published: January 2005

In Experiment 1, groups of rats 16, 19, 25, 32, and 90 to 120 days of age, were tested for retention of a passive avoidance response 2 min or 24 hr following a single training trial. Passive avoidance learning improved markedly with age, and retention over a 24‐hr interval was complete for all age groups. In Experiment 2, rats 19, 25, 32, and 90 to 120 days of age were trained in a simple, active avoidance task. A trials‐to‐criterion measure indicated that learning was relatively independent of age, although 19‐day rats were somewhat inferior to older rats. The occurrence of differences in passive avoidance learning through developmental ranges in age where simple active avoidance is little affected suggests that inhibition of responding may be selectively influenced by maturational variables.
Behavior of undisturbed 1‐ to 10‐day‐old chicks in different rearing conditions
Authors: Broom D. M.
Published: January 2005

Most of 11 measures of the behavior of undisturbed chicks showed a gradual increase in frequency of ocurrence between the 1st or 2nd and the 10th day. A group of 4 measures, associated with feeding, showed a peak at 6 days among isolated birds. These changes are related to studies of food reserve utilization and improvement in motor ability during this period. Group‐reared birds showed patterns of behavior change with increasing age similar to isolated, but showed them earlier.

Chicks were reared in conditions of different visual complexity and their behavior watched while they were undisturbed at 6 days. Where a moving object had been visible to the chicks during rearing, their behavior was much affected. Such birds spent much time as near to that object as a perspex partition would allow. If the object had been moving continuously, the birds were active for more of the observation period than were birds in grey‐walled pens, but conditions that were identical except for the lack of movement had no such effects on behavior.

Behavior development is changed and perhaps accelerated by certain increases in the complexity of a chick's environment.
Effect of differential rearing on photic evoked potentials and brightness discrimination in the albino rat
Authors: Edwards H. P. , Barry W. F. , Wyspianski J. O.
Published: January 2005

In two related experiments, albino rats were split into enriched and impoverished groups at weaning, and were reared for two months in differential environments, one group in a large cage containing toys, the other in individual cages. Photic evoked potentials were obtained from all subjects both at weaning and after differential rearing, and mean group latencies were compared. At the end of the experimental period, all subjects were tested on a black‐white brightness discrimination. It was found that although the groups did not differ in evoked potential latency at weaning, after differential rearing there were significant latency differences. The enriched group developed shorter latencies than the impoverished group. At the end of the experiment, the enriched group obtained superior scores on a brightness discrimination test. It was concluded that differential rearing has measurable effects on certain aspects of the albino rat's behavior and physiology.
Behavioral effects of neonatal irradiation of the cerebellum. II. Quantitative studies in young‐adult and adult rats
Authors: Wallace Robert B. , Altman Joseph
Published: January 2005

Young‐adult and adult rats whose cerebellum was focally irradiated with a variable number of daily doses of 200 r X‐ray during infancy were tested for spontaneous locomotion, in activity wheels, for muscular strength, in a weight‐pulling apparatus, and, for skill in coordination, in a rope‐climbing apparatus. Spontaneous activity declined as a function of number of daily irradiations; the interaction of treatment, age, and prior experience was also investigated. Weight pulling capacity, as determined by running time in an alleyway, was not affected by irradiation with 1 to 4 × 200 r with loads equalling the rats' own body weights. Ease of rope climbing was inversely related to the number of daily irradiations in terms of climbing time, number of shocks received, falls off the rope, and other criteria.
Responsiveness to simple and complex auditory stimuli in the human newborn
Authors: Turkewitz Gerald , Birch Herbert G. , Cooper Kenneth K.
Published: January 2005

The relative effectiveness of complex and simple auditory signals was examined by presenting 2‐day‐old infants with a sequence of stimuli consisting of a white noise and a variety of pure tones (which ranged from 250 to 8000 Hz). “Catch” trials during which no stimulus was presented were interspersed throughout. The frequency of occurrence during “catch” trials of each of the response indicators (cardiac acceleration, toward‐turning eye movements, and finger movements) was used as the baseline. Although the white noise stimulus elicited significantly more responses on each of the measures than occurred during “catch” trials, none of the pure tones produced significant changes in baseline rates for any of the measures. Failure to obtain an effect on pure tone stimulation could have stemmed from an intensity effect. Therefore, an additional group of infants was examined using pure tones that ranged in intensity from 50 to 80 db (the intensity range covered by the relevant component frequencies in the white noise). None of these stimuli at any of the intensities used had an effect on any of the measures.
Behavior and brain growth in rats treated with p‐chlorophenylalanine in the first weeks of life
Authors: Hole Kjell
Published: January 2005

Intraperitoneal injections of p‐chlorophenylalanine (pCPA) were given to 71 rats in the first 7 weeks of life, decreasing brain 5‐hydroxytryptamine concentrations to 20% of control values. The brain weight was significantly decreased, evident after 2 weeks of treatment, and also 52 days after the last injection. The retarded brain growth was not due to a general growth inhibition only: body weight was decreased initially, but from Day 24 the experimental animals gained weight more rapidly than the controls, resulting in a significantly higher body weight from Day 67.

The decrease in brain growth was accompanied by behavioral changes, evident later in life. The first test was given 4 weeks after the last pCPA‐injection. The changes observed were moderate, but consistent in all the tests. There were no learning deficits or clear motivational changes. In all the tests there was evidence of a reduced arousal level in the pCPA‐treated rats: latencies were long, exploration was low, habituation to new environment was fast, and the reactivity was low.
Effect of protein‐calorie malnutrition on the development of social behavior in rats
Authors: Fraňková Slávka
Published: January 2005

The effect of early protein‐calorie malnutrition on the development of social behavior was studied during the first weeks of postnatal life. Activity and social interaction were recorded in groups of young rats either in the rearing cage or in a novel enviornment. The malnourished group had a delayed development of social behavior and smaller number of social contacts in all tests. During the suckling period, the nutritionally deprived pups were also more dependent on the mother, showed no social grooming, but were also more aggressive. On the 49th day, the normal rats showed increased exploration of the social stimulus whereas the malnourished rats were markedly inhibited. Apparently, early nutritional deficiency altered the social structure of the litter and of all individuals from the beginning by disturbing behavior and interactions of all members of the “family”.
Effects of artificial mothers and visual experience on adrenal responsiveness of infant monkeys
Authors: Hill Suzanne D. , McCormack Shirley A. , Mason William A.
Published: January 2005

Rhesus monkeys, maternally seprated at birth, were individually housed with a simple artificial mother in cages that were either completely enclosed (Enclosed Group) or had a clear plastic fron that faced the general nursery environment (Visual Group). Animals were removed from the living cage and placed for 1 hr in an enclosed carrying cage, either alone or with the artificial mother, following which blood samples were taken and analyzed for plasma cortisol levels. This procedure was repeated at monthly intervals during the first 7 months of life and at 9 and 12 months. In both groups plasma cortisol levels were higher when the animlas were alone than when the social surrogate was present. Rearing conditions were also effective, as reflected in longitudinal and diurnal contrasts between groups: cortisol levels were consistently high in the Visual Group from the 1st week of life, whereas the developmental pattern was curvilinear for the Enclosed Group. Significant diurnal variation in cortisol level was demonstrated only in the Visual Group.
Phrenoblysis: Special brain and mind growth periods. II. Human mental development
Authors: Epstein H. T.
Published: January 2005

Spurts in the mental age of humans are shown to be recoverable from data giving the average mental age as a function of chronological age. Data from 13 independent studies are shown to give a highly consistent spectrum of ages at which spurts are found; these are 2‐4, 6‐8, 10‐12, and 14‐16, with an especially clear low rate of growth at 12‐14 yr. These ages correlate very well with those found for spurts in brain and skull sizes so that an obvious working hypothesis is that mutations for increased brain weight were selected for by virtue of the greater mental ability thus afforded to humans.
Vocal pathology in socially deprived monkeys
Authors: Newman John D. , Symmes David
Published: January 2005

Structural abnormalities were found in the clear calls of rhesus monkeys raised in partial social isolation. These abnormalities included abrupt pitch changes, harmonic emphasis shifts, temporal discontinuity, and lack of the characteristic inflection found in such calls from mother‐reared control monkeys. Other forms of vocalization appeared structurally normal. Vocal pathologies were distinctive for each isolate tested and persisted over the age range 8‐24 months.
Individual differences in infant orienting and autonomic conditioning
Authors: Ingram Eben , Fitzgerald Hiram E.
Published: January 2005

Conditioned discrimination and discrimination reversal of the skin potential response was attempted and subsequently demonstrated in 3‐month‐old infants. Analysis of individual subject data indicated individual differences in conditionability, as well as a significant relation between orienting response magnitude and conditionability. In general, high‐magnitude orienters discriminated; low‐magnitude orienters did not. Behavioral ratings of state, sex of subject, and stimulus order were not related to orienting or to conditionability.