bluuebunny/crossref_metadata_2025 huggingface dataset:
Carbon monoxide poisoning as a probe for the active site(s) of a nickel‐based olefin oligomerization catalyst
Authors: Clutterbuck Linda M , Field Leslie D , Humphries Geoffrey B , Masters Anthony F , Williams Mark A
Published: January 2005

The interaction of the olefin oligomerization catalyst system derived from [Ni(sacsac)(PBu3)Cl] (sacsac = pentane‐2,4‐dithionate = dithioacetylacetonate) with carbon monoxide (CO) has been examined by a combination of 31P NMR and FTIR spectroscopy. The catalyst is rapidly and completely inhibited by CO; however, removal of the CO restores catalytic activity. A CO‐adduct of the active catalyst has a characteristic CO stretching frequency of 2042 cm−1, and δ31P 9.9 ppm. Carbon monoxide does not react with [Ni(sacsac)(PBu3)Cl], but [Ni(sacsac)(PBu3)(Cl)] reacts with any of Et2AlCl, BuLi, Li[Et3BH] or K[(s‐Bu)3BH] under an atmosphere of carbon monoxide in the presence or absence of olefin to produce [Ni(PBu3)(CO)3], which has been identified by FTIR and 31P NMR. [Ni(sacsac)(PBu3)Cl] reacts completely with BuLi or K[(s‐Bu)3BH] to form catalytically inactive species which yield active catalysts on addition of Et2AlCl.
The electrochemical synthesis of metallocenes, polymethylmetallocenes, ‘open metallocenes’ and metal phenylacetylides
Authors: Casey Allan T , Vecchio Angelica M
Published: January 2005

Metallocenes, polymethylmetallocenes, metal dimethylpentadienyls and metal phenylacetylides were synthesized by the oxidation of the metal in a solution (acetonitrile, acetonitrile/tetrahydrofuran or acetonitrile/1,2‐dimethoxyethane) of the carbon acid C*H (where C*PhCC, C5H5, CH3C5H4, (CH3)5C5, indenyl, fluorenyl and 2,4‐dimethylpentadienyl). Metallocenes were extracted with hexane and sublimed in vacuo. Metal phenylacetylides precipitated during electrolysis. Current efficiencies indicate Faradaic behaviour. The method provides a significant improvement over the conventional route via alkali metal salts of the carbon acid.
Characteristics of selenium in australian marine biota
Authors: Maher W , Baldwin S , Deaker M , Lrving M
Published: January 2005

The occurrence, distribution and speciation of selenium in Australian marine biota is discussed. Biochemical pathways for the accumulation of selenium by marine organisms are also postulated. Comparison of the levels of selenium in macroalgae, fish, crustaceans and molluscs indicates that preferential accumulation of selenium by particular taxa does not occur. Phaeophyta have significantly lower selenium concentrations than Rhodophyta and Chlorophyta. Fish have lower selenium contents in muscle tissues than molluscs and crustaceans. Marine animals with different dietary intake (planktonic vs herbivorous vs carnivorous) are not observed to have significantly different levels of selenium (P>0.05). Selenium in all the organisms studied was predominantly associated with free amino‐acids or protein residues and was not present as characterizable inorganic selenium species (SeO32−, SeO42−). These results indicate that selenium is probably only incorporated into biota for specific biochemical purposes with any exces selenium being excreted or eliminated.
The fate of organoarsenic compounds in marine ecosystems
Authors: Hanaoka Ken′Ichi , Tagawa Shoji , Kaise Toshikazu
Published: January 2005

Microbial degradation experiments were performed with each standard arsenical [arsenobetaine, trimethylarsine oxide, dimethylarsinic acid, methanearsonic acid, inorganic arsenic(V) and inorganic arsenic(III)]. As typical origins for marine micro‐organisms, sediments, macro‐algae, mollusc intestine and suspended substances were used. The results were from these experiments led us to the following conclusions: (1) there is an arsenic cycle which begins with the methylation of inorganic arsenic on the route to arsenobetaine and terminates with the complete degradation of arsenobetaine to inorganic arsenic; (2) all the organoarsenic compounds which are derived from inorganic arsenic in seawater, through the food chains, have the fate that they, at least in part, finally return to the original inorganic arsenic.
Liquid–solid extraction of butyltin compounds from marine samples
Authors: Chiavarini S , Cremisini C , Ferri T , Morabito R , Ubaldi C
Published: January 2005

Environmental damage due to organotins (TBT, DBT, MBT) released from antifouling paints is well documented. The concentrations of these compounds in seawater are usually at ppt (parts per 1012) levels. Many analytical techniques, including chromatographic and spectrophotometric ones, have been presented in the literature to detect organotins at these low levels. Liquid‐liquid extraction is commonly employed as a concentration method. However, it presents some disadvantages during sampling campaigns and requires large volumes of toxic and expensive solvents. In this paper we propose an analytical method based on a liquid‐solid extraction procedure that can be easily performed in the field and is characterized by good recoveries and high enrichment factors. Three different solid phases (Carbopack, LC 8 and LC 18) and five different eluting agents (methanol/tropolone, methanol, dichloromethane, hexane and diethyl ether) were evaluated. Carbopack and LC 18 were the most suitable solid phases. Inorganic tin was not retained on these solid phases and a separation of TBT from DBT and MBT was achieved, performing the elution in two steps with methanol and methanol/tropolone. In this way GF AA was suitably employed to obtain butyltin speciation data.
New organotin catalysts in urethane and polyurethane technology
Authors: Ratier M , Khatmi D , Duboudin J G
Published: January 2005

The use of organotin α‐substituted alcohols and carbamates as catalysts has been investigated in urethane and polyurethane preparations. These compounds have been shown to be new and very active catalysts. The mechanism of the reaction has been studied.
Historical cohort studies in three arsenic poisoning areas in japan
Authors: Tsuda Toshihide , Ogawa Takanori , Babazono Akira , Hamada Hirohisa , Kanazawa Susumu , Mino Yoshio , Aoyaam Hideyasu , Yamamoto Eiji , Kurumatani Norio
Published: January 2005

The results of historical cohort studies of three arsenic poisoning incidents in Japan are presented. The first episode was in a small mountainous community near an arsenic mine and refinery, at Toroku, where patients with chronic arsenism were certified by application of the Pollution Health Damage Compensation Law. The second area was in a small town, Namiki‐cho, near Nakajo‐machi, where wells were poisoned by arsenic produced in an arsenic(III) sulfide factory. As to the third cohort, eight residents of Nishikawa‐machi who ingested well‐water suffered arsenic poisoning about 35 years ago. The standardized mortality ratios were used in analyzing these data. Excesses of cancer mortality, especially lung cancer, were observed among the subjects in these areas. In Japan, there are many arsenic poisoning episodes, involving for example soy‐sauce poisoning, powdered‐milk poisoning and other incidents associated with arsenic mines. Thus it is necessary to clarify the chronic effects of arsenic in these areas.
Intake of different chemical species of dietary arsenic by the japanese, and their blood and urinary arsenic levels
Authors: Yamauchi Hiroshi , Takahashi Keiko , Mashiko Mari , Saitoh Juichiro , Yamamura Yukio
Published: January 2005

We calculated the intake of each chemical species of dietary arsenic by typical Japanese, and determined urinary and blood levels of each chemical species of arsenic. The mean total arsenic intake by 35 volunteers was 195±235 (15.8‐1039) μg As day−1, composed of 76% trimethylated arsenic (TMA), 17.3% inorganic arsenic (Asi), 5.8% dimethylated arsenic (DMA), and 0.8% monomethylated arsenic (MA): the intake of TMA was the largest of all the measured species. Intake of Asi characteristically and invariably occurred in each meal. Of the intake of Asi, 45‐75% was methylated in vivo to form MA and DMA, and excreted in these forms into urine. The mean measured urinary total arsenic level in 56 healthy volunteers was 129±92.0 μg As dm−3, composed of 64.6% TMA, 26.7% DMA, 6.7% Asi and 2.2% MA. The mean blood total arsenic level in the 56 volunteers was 0.73±0.57 μg dl−1, composed of 73% TMA, 14% DMA and 9.6% Asi. The urinary TMA levels proved to be significantly correlated with the whole‐blood TMA levels (r = 0.376; P<0.01).
Elevated tri(n‐butyl)tin concentrations in shellfish and sediments from Suva Harbour, Fiji
Authors: Stewart C , De Mora S J
Published: January 2005

Tri(n‐butyl)tin (TBT) concentrations were determined in sediments and selected shellfish from Suva Harbour, Fiji. Sediments in the immediate vicinity of foreshore slipways and boatyards were exceedingly contaminated, with a maximum observed level of 38μ g−1 TBT‐Sn. Concentrations were much lower in surficial sediments from commercial docks and yacht mooring areas, namely 16–83 ng g−1 TBT‐Sn. Mangrove oysters (Crassostrea mordax), gastropods (Thais mancinella), and bivalves (Anadara scapha) were found to have accumulated TBT. Concentrations as high as 3180 ng g−1 TBT‐Sn were found in mangrove oysters. With respect to the mangrove oyster, its widespread distribution, abundance and proclivity to accumulate TBT suggest that it is likely to be the best bioindicator species of TBT contamination in Fijian coastal waters.
Spermatocyte chromosome alterations in truncatella subcylindrica (L., 1767) (Mollusca, Mesogastropoda) following exposure to dibutyltin(IV) and tributyltin(IV) chlorides
Authors: Vitturi R , Mansueto C , Catalano E , Pellerito L , Girasolo M A
Published: January 2005

In order to analyze chromosomes for possible numerical and structural alterations in response to exposure to organotin(IV) compounds, gastropod Truncatella subcylindrica specimens were treated with dibutyltin(IV) and tributyltin(IV) chloride solutions with different exposure times.

Experimental evidence suggests that tributyltin(IV) chloride is more toxic to this organism than dibutyltin(IV) dichloride at low concentrations. Furthermore, the toxicity responses to these organotin(IV) derivatives seem to be proportional to both concentration and exposure time.

The following structural lesions have been identified by comparative analysis of spermatocyte chromosomes from untreated specimens and specimens treated with organotin(IV) compounds: (1) breakages; (2) bridging; (3) irregular outline; and (4) light areas after staining with acetic orcein. In this respect, dibutyltin(IV) and tributyltin(IV) chlorides seem to have an effect similar to that of colchicine.
The determination of organotin compounds in fruit juices using gas chromatography‐atomic absorption spectrometry
Authors: Forsyth D S , Weber D , Barlow L
Published: January 2005

A method for extracting butyl‐, cyclohexyl‐, octyland phenyl‐tin compounds in fruit juices was developed using 0.05% tropolone in 25% pentane/diethyl ether. Methyl derivatives formed by Grignard reaction were quantified by gas chromatography‐atomic absorption spectrometry. Several fruit juices contained low ng cm−3 levels of butyl‐ and octyl‐tins. Gas chromatography‐mass spectrometry, used for the confirmation of the butyl‐ and octyl‐tins, also detected phenyl‐ and cyclohexyl‐tin compounds at levels below the GC AA detection limits (0.03–0.05 ng Sn cm−3).
Synthesis and spectroscopic characterization of dicyclohexyltin derivatives of dipeptides, and in vitro effects against MDA‐MB 231 breast cancer cells: Crystal structures of dicyclohexyltin glycylglycinate and glycylalaninate
Authors: Huber Friedo , Vornefeld Michael , Preut Hans , von Angerer Erwin , Ruisi Giuseppe
Published: January 2005

Dicyclohexyltin derivatives Cy2SnL (Cy = cyclohexyl) of the dipeptides H2L, glycylglycine, glycylalanine, alanylglycine, glycylvaline, glycylmethionine, glycylphenylalanine and glycyltyrosine, have been obtained by neutralization of Cy2SnO and H2L.

The crystal structures of Cy2SnL (L = glycylglycinate, glycylalaninate) have been determined by single X‐ray diffraction. Tin in each case has a distorted trigonal bipyramidal environment with the dipeptide acting as a tridentate NNO‐ligand. From IR‐data, and in some cases from 119Sn Mössbauer and 119Sn NMR data, analogous molecular structures are inferred for the other compounds Cy2SnL. Spectroscopic data indicate that the solid‐state structures are retained in organic solvents.

In vitrotests showed Cy2SnL (H2L = glycylglycine, glycylalanine, alanylglycine, glycylphenylalanine, glycyltyrosine) to exhibit high cytotoxicity against MDA/MB 231 breast cancer cells, while Me2SnL (L = glycylalaninate, glycyltyrosinate, glycyltryptophanate), and R2Snglycylglycinate (Rn‐Bu, Ph) proved to be much less active.
Organometallic Langmuir‐Blodgett films for electronics and photonics
Authors: Nalwa Hari Singh , Kakuta Atsushi
Published: January 2005

This review provides a brief introduction to the Langmuir‐Blodgett (LB) technique and to the utilization of ultrathin films in the fields of electronics and optics. The electrical and nonlinear optical properties of the Langmuir‐Blodgett monolayer and multilayers of organoruthenium complexes, ferrocene derivatives, metal(4,5‐dimercapto‐1, 3‐dithiol‐2‐dithiolene)2 complexes, metallophthalocyanines, metalloporphyrins, metal(dibenzotetra‐aza[14]annulene)s and siloxane polymers are presented. Possible applications of organometallic LB films in sensors, electroluminescence and electrochromic devices, optical switches, solar cells, infrared detectors and harmonic generators are discussed.
Coordination and organometallic chemistry of cyclophosphazenes and polyphosphazenes
Authors: Chandrasekhar V , Thomas K R Justin
Published: January 2005

This review describes the chemistry of cyclophosphazene and polyphosphazene ligand systems and their transition and organometallic complexes. The structures of the ligands and the complexes are discussed.
Synthesis, characterization and in vitro antitumour activity of diorganotin bisxanthates [R2Sn(S2COR′)2] (R=Me, Et, nBu, Ph; R′=Et, iPr, Hex) and crystal structure of bis(O‐ethyldithiocarbonato)diphenyltin(IV)
Authors: Donoghue Neil , Tiekink Edward R. T. , Webster Lorraine
Published: January 2005

A series of diorganotin bisxanthate compounds, [R2Sn(S2COR′)2] (R=Me, Et, nBu, tBu, and Ph; R′Et, iPr and cHex) have been prepared and characterized by spectroscopic methods (IR, NMR and FAB MS). The xanthate ligands chelate the R2Sn moieties forming disparate Sn–S bonds leading to skew‐trapezoidal biypramidal tin atom geometries. The crystal structure of a representative compound, [Ph2Sn(S2COEt)2], confirms the spectroscopic results and shows the tin atom to be coordinated by two asymmetrically chelating xanthate ligands [Sn–S(1) 2.486(1), Sn–S(2) 3.052(1) Å and Sn–S(3) 2.484(1), Sn–S(4) 3.220(1) Å] with the two phenyl substituents lying over the weaker Sn–S interactions so that C–Sn–C is 126.5(1)∘. Crystal data for [Ph2Sn(S2COEt)2]: monoclinic space group P21/n: a=9.645(1), b=23.723(3), c=9.798(2) Å, ß=100.23(1)∘, V=2206.2 Å3, Z=4; 2708 data refined to final R 0.023. A selection of these compounds has been evaluated for activity against the L1210 mouse leukaemia cell line.
Organobismuth(III) and organobismuth(V) carboxylates and their evaluation as paint driers
Authors: Ali Mushtaq , McWhinnie William R
Published: January 2005

A range of bismuth and organobismuth carboxylates has been prepared e.g. Bi(carboxylate)3; PhBi(carboxylate′)2; and Ph3Bi(carboxylate″)2 where carboxylate=octanoate, i.e. 5‐ethylhexanoate; carboxylate′=acetate and monomaleate; carboxylate″=acetate, propionate, benzoate, 5‐ethylhexanoate, and 0.5 oxalate. A combination of IR (solid) and NMR (solution) studies suggests that in the case of the bismuth(V) compounds the carboxylates may be inequivalent in the crystalline forms but equivalent in solution. The compounds have been tested as driers in two paint formulations, Synolac 50W (linseed‐based) and Sorbal P470 (linoleic‐rich). Although initially promising results were obtained for Synolac 50W, the shelf life of the bismuth driers was poor. With Sorbal P470, bismuth driers were inferior to established formulations. However, a combination of Bi(OOCH7H15)3 with tris(diethyldithiocarbamato)‐bismuth(III) out‐performed established driers.
Matrix effects in the determination of butyltin compounds in environmental samples by GC AA after hydride generation
Authors: Quevauviller Ph , Martin F , Belin C , Donard O F X
Published: January 2005

Experiments for the determination of mono‐, di and tri‐butyltin (MBT, DBT and TBT) by hydride generation/gas chromatography/atomic absorption spectrometry in various matrices (sediment, suspended matter, mussel, algae and water) have revealed that poor butyltin recoveries are obtained in sediments displaying high sulphur and hydrocarbon contents; very poor recoveries were also observed for TBT in sediments with high chlorophyll pigment contents as well as in algal samples. It was however not clear whether the hydride generatin was inhibited by these infering compounds, as was previously assumed in the case of hydrocarbons, or whether interferences affected the atomization rate. Further studies were performed to solve this problem in order to validate this method in the case of analyses of, for example, oil‐contaminated sediment and algae. This paper presents the results obtained. It is concluded here that the poor recoveries were due to an inhibition of hydride generation rather than to interference at the atomization stage.
Antifertility and biocidal activities of organometallics of silicon, germanium, titanium and zirconium derived from 2‐acetylthiophene thiosemicarbazone
Authors: Singh Devendra , Kumari Anita , Singh R V , Mehta S M , Gupta I J , Singh K
Published: January 2005

A comparative biochemical study of four Group IV element compounds with specific sulphur‐containing organic substrates has been carried out and discussed. The structural characterizations of these organometallics, viz. Me2SiLCl, Me2SiL2, Me3SiL, Ph2SiLCl, Ph2SiL2, Ph3SiL, Ph3GeL, Cp2TiLCl, Cp2TiL2, Cp2ZrLCl and Cp2ZrL2 (where LH2‐acetylthiophene thiosemicarbazone) had been deduced on the basis of various physico‐chemical and instrumental techniques, viz., IR, UV, 1H NMR, 13C NMR AND 29SI NMR spectral studies. All the organometallics and the parent thiomine have been screened against a number of microbes and their sterilizing power in male mice tested. The results of these biocidal studies show that the organosilicon(IV) and organogermanium(IV) compounds are more active than the organotitanium(IV) and organozirconium(IV) derivatives. An attempt has also been made to correlate the structural aspects of the molecule with its biological activity.
Effects of tributyltin(IV) chloride exposure on early embryonic stages of Ciona intestinalis: In vivo and ultrastructural investigations
Authors: Mansueto C , Gianguzza M , Dolcemascolo G , Pellerito L
Published: January 2005

The effects of tributyltin(IV) chloride (TBT chloride) solutions on ascidian embryos of Ciona intestinalis have been tested at different stages of development. It has been observed, in vivo, that TBT chooride inhibited cleavage of fertilized eggs and of embryo blastomeres giving rise to cellular masses that are not delimited by plasma membrane. Electron‐dense precipitates of TBT chloride, probably as inorganic tin, have been observed by transmission electron microscopy in the egg cytoplasm of cellular masses.

The same type of precipitate was present also inside the mitochondria, whose structure appeared to be highly modified. These ultrastructure aspects are indicative of a degenerative process of the embroys after incubation in TBT chloride.
The effect of arsenicals on alkaloid production by cell suspension cultures of Catharanthus roseus
Authors: Cullen William R , Hettipathirana Deepthi I
Published: January 2005

The effect of arsenic compounds on indole alkaloid production by cell suspension cultures of Catharanthus roseus was investigated. The analysis of indole alkaloids was achieved by using thermospray liquid chromatography‐mass spectrometry (LC MS) which facilitated the rapid screening of alkaloid composition in cultures treated with different arsenicals at different times in their growth cycle.

Treatment with dimethylarsinate (DMA), a non‐selective herbicide, has a drastic inhibitory effect on alkaloid production although it is the least toxic arsenical to growth. Tryptamine, an early precursor in the biosynthesis of indole alkaloids, accumulates in cells treated with DMA, indicating that the initial step of condensation of tryptamine with secologanin is inhibited. Treatment with DMA during the early stationary phase of culture growth enhances the accumulation of some alkaloids, although some, such as catharanthine, are suppressed.

The arsenicals arsenate and methylarsonate (MMA) have an inhibitory effect on alkaloid production when applied during the early growth stages. In contrast to MMA and DMA, arsenate has a stimulatory effect on catharanthine production when introduced to the culture during its early stationary phase.

Thus the changes in the pattern of alkaloid accumulation on addition of arsenicals are dependent on the arsenic species and its concentration, as well as the time of application. This variable response indicates that each arsenical has a distinct mode of action on the secondary metabolic pathways of C. roseus.
Refractory methylated arsenic compounds in estuarine waters: Tracing back elusive species
Authors: De Bettencourt A. M. , Florêncio M. H. , Duarte M. F. N. , Gomes M. L. R. , Vilas Boas L. F. C.
Published: January 2005

Water from the Tagus estuary, Portugal, was concentrated and purified through evaporation, solvent extraction, ion exchange and HPLC, and peaks of refractory arsenicals were detected by difference between total arsenic (GF AA) and hydride‐forming arsenic species (HG QF AA). DCI mass spectra of these fractions presented peaks at m/z 139, 157 and 159; the proportion of m/z 157 and 159 peaks, approx. 3:1, suggested a chlorinated moiety. DCI MS/MS daughter‐ion fragmentation of these peaks seems compatible with dimethylarsenic (cacodylic) acid and structures of the type Me2As(O)Cl or Me3As(OH)F. The refractory character of these fractions, however, cannot be explained by these structures. Further work with mixtures of halogen and arsenic species injected in the HPLC system showed that fluoride and iodide can shift DMA (dimethylarsenic) and TMAO (trimethylarsine oxide) to shorter retention times but not to Rf values similar to refractory arsenicals. These latter are attained by mixtures of sodium chloride + arsenobetaine, and sodium fluoride and chloride + arsenocholine. We suggest that peaks at m/z 139 and 157 correspond to fragments of a heavier refractory molecule mainly formed by halogenated betaines including chloroarsenobetaine and chloro‐ and fluoro‐arsenocholine.
A study of trialkyltin β‐aryl‐β‐triphenylgermyl propionates
Authors: Qing‐Lan Xie , Li‐Juan Sun , Hua Liu , Ru‐Ji Wang , Hong‐Gen Wang
Published: January 2005

Twenty new compounds of the form Ph3GeCHArCH2COOSnR3 (R = n‐Bu, cyclohexyl; Ar = substituted phenyl) have been synthesized. Their structures were characterized by IR and 119Sn and 1H NMR spectroscopy. The compounds are five‐coordinated carboxylate bridged polymers when R = n– Bu; when R = cyclohexyl (Cy) they are four‐coordinate. 119Sn NMR measurements of chemical shift for the two series of compounds have shown that there is a good linear relationship for the chemical shift of 119Sn NMR between the tributyltin and tricyclohexyltin propionates, viz. δ119Sn(Bu3Sn) = 1.0474 δ 119Sn(Cy3Sn) + 95.8076, n = 5, r = 0.993. The structure of one compound was determined by X‐ray diffraction. It exists as a monomeric four‐coordinated species in a distorted tetrahedronal geometry.
Volatile metal and metalloid species in gases from municipal waste deposits
Authors: Hirner Alfred V. , Feldmann Jörg , Goguel Reiner , Rapsomanikis Spyridon , Fischer Ralf , Andreae Meinrat O.
Published: January 2005

We have detected volatile species of silicon, vanadium, arsenic, bromine, tin, antimony, tellurium, iodine, mercury, lead and bismuth in gases released from domestic waste deposits, using inductively coupled argon plasma mass spectrometry (ICP MS). By concurrent aspiration of a multielement standard solution for calibration, the element concentrations in deposit gas are found to be in the range from 0.1 ng m−3 to 10 μg m−3 gas. The global amount of some metal species emitted by this process may be of the order of several tons per year. These results suggest a biogeochemical pathway for the transfer of metals into the atmosphere via volatile species. This process may have significant influence on atmospheric cycling of metals as well as on metal toxicity within ecosystems.
Bioaccumulation and excretion of arsenic compounds by a marine unicellular alga, polyphysa peniculus
Authors: Cullen William R. , Harrison Lionel G. , Li Hao , Hewitt Gary
Published: January 2005

Polyphysa peniculus was grown in artificial seawater in the presence of arsenate, arsenite, monomethylarsonate and dimethylarsinic acid. The separation and identification of some of the arsenic species produced in the cells as well as in the growth medium were achieved by using hydride generation–gas chromatography–atomic absorption spectrometry methodology. Arsenite and dimethylarsinate were detected following incubation with arsenate. When the alga was treated with arsenite, dimethylarsinate was the major metabolite in the cells and in the growth medium; trace amounts of monomethylarsonate were also detected in the cells. With monomethylarsonate as a substrate, the metabolite is dimethylarsinate. Polyphysa peniculus did not metabolize dimethylarsinic acid when it was used as a substrate. Significant amounts of more complex arsenic species, such as arsenosungars, were not observed in the cells or medium on the evidence of flow injection–microwave digestion–hydride generation–atomic absorption spectrometry methodology. Transfer of the exposed cells to fresh medium caused release of most cell–associated arsenicals to the surrounding environment.
Amending cultures of selenium‐resistant bacteria with dimethyl selenone
Authors: Zhang Limin , Chasteen Thomas G.
Published: January 2005

A possible biological intermediate in the reduction and methylation of selenium oxyanions, dimethyl selenone, was synthesized, and the first experiments involving the amendment of selenium resistant bacterial cultures with this compound are reported. The amount of volatile, reduced selenium‐containing species released from these cultures into the headspace is significantly more than that produced in analogous experiments involving sodium selenate amended cultures. Dimethyl selenone is reduced in the presence of dimethyl sulfide and dimethyl disulfide in a complex growth medium, trypticase soy broth with 0.1% nitrate. This reduction occurs whether or not the reduced sulfur compounds are biologically produced.
Determination of methylmercury in human hair by capillary GC with electron capture detection
Authors: Chiavarini Salvatore , Cremisini Carlo , Ingrao Giovanni , Morabito Roberto
Published: January 2005

An analytical procedure was developed for the determination of methylmercury in human hair using capillary gas chromatography with electron capture detection (GC–ECD). Hair samples are digested in alkaline solution/toluene in an ultrasonic bath at about 50°C. After cooling and treatment with hydrochloric acid (6 mol I−1) and a saturated solution of copper sulphate, the organic phase is extracted with a cysteine solution. Methylmercury is back‐extracted in toluene by adding copper sulphate and potassium bromide and analysed by GC–ECD using a DB17 capillary column. The practical detection limit of the method for methylmercury is 50 ng g−1 using 100 mg of hair sample. Column performances and injection reproducibility have been evaluated. Results on 13 samples of human hair are presented and related to the total mercury concentration. The method, consisting of the optimization of similar analytical procedures through improvements in the various steps, allows for sensitive and reliable quantitation of methylmercury in hair with good precision and accuracy.
On‐Line speciation of mercury and methylmercury in aqueous samples by chromatography‐atomic fluorescence spectrometry after hydride generation
Authors: Ritsema Rob , Donard Olivier F. X.
Published: January 2005

A method is described for the determination of picogram amounts of inorganic mercury(II) and methylmercury(II) compounds in seawater. These compounds are first volatilized from the water samples by reduction to mercury (Hg0) and formation of methylmercury hydride (CH3HgH) by means of a sodium borohydride (NaBH4) solution and cryogenically focused onto a chromatographic stationary phase. Both mercury compounds are eluted according their boiling points and are passed through a pyrolysis tube, at 900°C, before entering the atomic flurescence detector. Absolute detection limits (3σ) are 1 and 2 pg for, respectively, inorganic mercury and methylmercury. For seawater analysis, detection limits of 0.1–1.0 ng I−1 can be achieved.
Interlaboratory study for the improvement of tributyltin determination in harbour sediment (rm 424)
Authors: Quevauviller Ph. , Astruc M. , Ebdon L. , Kramer G. N. , Griepink B.
Published: January 2005

Following two interlaboratory studies on tributyltin species (TBT) in water and TBT‐spiked sediment, the EC Community Bureau of Reference (BCR) (Measurements and Testing Programme) organized in 1992 an interlaboratory study on TBT in a harbour sediment (RM 424) to investigate sources of error possibly occurring in the analysis of a complicated matrix and to attempt to certify this material. The sediment was collected in the Sado Estuary (P), then carefully prepared, and its homogeneity and stability were verified. The low TBT content encountered in this material, and the high level of interferences, created difficulties with the techniques using hydride generation, whereas better agreement was obtained for other derivatization techniques with GC/FPD and GC/MS. This paper presents the results of the interlaboratory study. The reference value for TBT in this material is 20±5 ng g−1 (as TBT cation) and the indicative values for dibutyltin (DBT) and monobutyltin (MBT) are 53±19 ng g−1 (as DBT cation) and 257±54 ng g−1 (as MBT cation), respectively. Owing to the difficulties encountered, the reference material was not certified and is considered as a research material to be used for the evaluation of the performance of analytical techniques for the determination of low TBT levels in a difficult matrix.
Quality control in the routine analysis of methylmercury in biological and environmental materials using gas chromatography with electron capture detection
Authors: Rubi E. , Lorenzo R. A. , Casais M. C. , Cela R.
Published: January 2005

In the application of GC ECD procedures for methylmercury analysis and organomercury speciation, frequent column‐treatments must be carried out to maintain the analytical system under statistical control. Often the decision to carry out a new treatment is taken without any statistical assistance. Several quality control techniques have been applied to decide the best time to make these treatments. A Trigg tracking signal chart in combination with a moving estimate of standard deviation charts gives the best indication about the timing of each new treatment.
Methylmercury determination by Purge and Trap–GC–FTIR–AAS after NaBH4 derivatization of an environmental thiosulfate extract
Authors: Filippelli Marco
Published: January 2005

A method of detecting methylmercury species (MeHg) and dimethylmercury (DMM) has been studied. MeHg was transformed prior to its determination as methylmercury hydride (MMH) by use of NaBH4. The two volatile forms of organic mercury were detected by a purge and trap (PT) unit in‐line with a gas chromatograph (GC) connected with a Fourier transform infrared spectrometer (FTIR) which was also in‐line with an atomic absorption spectrometer (AAS). Environmental samples were analyzed by this technique. MeHg was detected in thiosulfate extracts of fish and sediment, and MeHg and DMM directly in water samples. Picogram levels of sensitivity were obtained, the limit of detection being 100 pg for MeHg and 50 pg for DMM. The calibration graph was linear for both compounds up to 10 ng as Hg.
Pentylated organotin standards: Guidelines for their synthesis, purity control and quantification
Authors: Dirkx W. M. R. , Adams F. C.
Published: January 2005

Pentylated derivatives of six environmentally important organotin compounds were obtained by using a Grignard derivatization. The purity of these pentylated calibrants was checked by gas chromatography–quartz furnace atomic absorption spectrometry (GC QFAA) and gas chromatography–mass spectrometry ion‐trap detection (GC MS‐ITD). Through combination of the total tin contents of every pentylated organotin standard, obtained after wet acid destruction of 0.5 ml of the respective calibrant, and the species composition or impurities present in the same standard, a well‐defined pentylated organotin standard was obtained which could be used to calibrate GC QFAA and GC atomic emission detection (AED) systems.

In a similar way aqueous organotin standards can be obtained, which can be used in spiking experiments to verify the recovery efficiency of a developed analytical extraction procedure for organotins.
Polygermoxanes suitable for biochemical purposes: II Linear trigermoxanes (high‐viscosity oils)
Authors: Duverneuil Gilles , Mazerolles Pierre , Perrier Elisabeth
Published: January 2005

Linear trigermoxanes, R1 RGeOGe(R3)2OGeRR1, a new series of organogermanium compounds, were synthesized by reaction of a lithium organogermanolate with a suitable organogermanium dihalide. With alkyl or phenyl substituents, these trigermoxanes are structurally unstable viscous oils, due to redistribution reactions. When R3 substituents are bulky groups, such as mesityl, trigermoxanes are thermally and structurally stable oils; depending on the R1 and R2 substituents their viscosities lie in the range 240 to more than 1500 cPo (mPa s) at 20°C. When both terminal germanium atoms are substituted with two mesityl groups, trigermoxanes are stable glassy solids.
Determination of organotin compounds in marine sediments using graphite furnace atomic absorption spectrometry
Authors: Mortensen Gitte , Pedersen Britta , Pritzl Gunnar
Published: January 2005

Organotin compounds, especially tributyltin, began to cause concern 10 years ago due to a high toxicity towards marine organisms. Several methods of analysing organotin compounds in various matrices have already been developed to determine organotin species simultaneously, but these are quite expensive as special equipment and specialized staff are needed. A simple screening method, which determines the organic tin compounds in the sediment, has therefore been developed and validated. The method can easily be implemented in laboratories accustomed to tracelement analyses; the sediment is extracted by a two‐phase extraction and the organic extract is analysed using graphite furnace atomic absorption spectrometry (GF AA.) The screening method has been validated using high‐pressure liquid chromatography‐inductively coupled plasma mass spectrometry (HPLC–ICP MS).
Arsenobetaine as the major arsenic compound in the muscle of two species of freshwater fish
Authors: Shiomi Kazuo , Sugiyama Yasuo , Shimakura Kuniyoshi , Nagashima Yuji
Published: January 2005

The chemical form of arsenic contained in the muscle of certain freshwater fish was examined using cultured specimens of rainbow trout (Salmo gairdneri) and wild specimens of Japanese smelt (Hypomesus nipponensis). More than 95% of the total arsenic of both species was extracted with methanol and recovered in the water‐soluble fraction. The major arsenic compound of both species was purified by cation‐exchange chromatography on Dowex 50, gel filtration on Bio‐Gel P‐2 and HPLC on Asahipak GS‐220H. Behavior in the above purification procedure and analyses of the purified compounds by HPLC–ICP and TLC confirmed that the major arsenic compound of both species was arsenobetaine. Arsenobetaine found in cultured rainbow trout seems to be derived from the commercial assorted feed containing arsenobetaine as the major arsenical. On the other hand, the result with wild Japanese smelt suggested that arsenobetaine is a naturally occurring compound in the freshwater environment.
Fungicidal, bactericidal and antifertility activities of diorganosilicon(IV) complexes derived from benzothiazolines
Authors: Kumari A. , Singh I. , Tandon J. P.
Published: January 2005

Synthetic, structural and biological aspects of trigonal‐bipyramidal, Me2S(N—S)CI and octahedral, Me2Si(N—S)2 types of diorganosilicon(IV) complexes of heterocyclic benzothiazolines (N—SH) are described. The complexes were characterized by elemental analysis, molecular weight determination, conductance measurements and electronic, infrared, 1H and 13C NMR spectroscopic studies. Some ligands and their corresponding dimethylsilicon(IV) complexes have been tested for their effects on several pathogenic fungi and bacteria and found to be quite active in this respect. Antifertility activity in male mice of some representative ligands and their silicon complexes was also evaluated and discussed.
Selenium speciation by high‐performance liquid chromatography with on‐line detection by atomic absorption spectrometry
Authors: Lei Tian , Marshall W. D.
Published: January 2005

Several approaches to the determination of selenomethionine, selenocystine, selenite and selenate by high‐performance liquid chromatography with online detection by atomic absorption spectrometry are described. The N−2,4‐dinitrophenyl derivatives of selenomethionine, selenoethionine, selenocystine and phenylmercury(II) cystineselenoate were recovered from aqueous solution, separated on a Nucleosil 5‐NO2 reversed‐phase HPLC column with a methanolic mobile phase containing acetic acid and triethylamine, and detected with a quartz thermochemical hydride‐generating interface–atomic absorption spectrometry (AA) system. The restriction of having to perform chromatography with an organic mobile phase (to support the combusion process) was overcome with a new interface design capable of operation with either organic or aqueous HPLC mobile phases. Using aqueous acetic acid (0.015% v/v) containing 0.1% (w/v) ammonium acetate delivered at 0.5cm3 min−1, selenate, selenite, selenomethionine, selenocystine and selenoethionine were separated virtually to baseline on a cyanopropyl‐bonded phase HPLC column. Other selenium compounds which were investigated included methane seleninic and methane selenonic acids as well as the crude oxidation product mixtures resulting from the treatment of selenomethionine and selenocystine with hydrogen peroxide. A procedure for extracting selenate, selenite, selenomethionine, selenocystine and selenoethionine from spiked water or ground feed supplement into liquefied phenol resulted in acceptable recoveries for the latter four analytes but was unacceptably low for selenate.
Di(n‐butyl)tin bis(dihydroxybenzoate)s: Synthesis, spectroscopic characterization and in vitro antitumour activity
Authors: Gielen Marcel , Bouhdid Abdeslam , Kayser Françcois , Biesemans Monique , Willem Rudolph , De Vos Dick , Mahieu Bernard
Published: January 2005

Six di(n‐butyl)tin(IV) and two dimethyltin(IV) bis‐(dihydroxybenzoate)s were synthesized and characterized by 1H, 13C and 119Sn NMR and Mössbauer spectroscopy. Five of the di(n‐butyl)tin compounds were screened in vitro against six human tumour cell lines, MCF‐7, EVSA‐T, WiDr, IGROV, M19 and A498. They are more active than carboplatin, cisplatin and 5‐fluorouracil against all cell lines and of comparable activity or better than methotrexate. All dihydroxybenzoates with an ortho‐bydroxyl group are more active against MCF‐7 cells than substituted salicylates screened previously.
Reagent control of stereochemistry in allylic additions to chiral aldehydes with CpMo(NO)(X)(2‐methallyl) complexes of high enantiomeric purity
Authors: Faller J. W. , Nguyen Jenna Thu , Mazzieri Maria R.
Published: January 2005

Reactions of (R)‐ and (S)‐CpMo(NO)(η3‐methallyl)X(X=camphorsulfonate, Cl, Br, I) with chiral α‐substituted aldehydes yield homoallylic alcohols with high diastereoselectivity. Reactions of (R)‐ and (S)‐CpMo(NO)(η3‐ methallyl)L S[LS = (IS)‐(+)‐10‐camphorsulfonate] with D‐glyceraldehyde acetonide yield the corresponding homoallylic alcohols in >98% diastereomeric excess. Reactions with racemic 2‐phenyl‐propionaldehyde and nonracemic 3‐benzyloxy‐2‐methylpropanol are also considered and show that there is very high reagent control of stereo‐chemistry in additions to the carbonyl group.
η‐Cu3Si percentage and particle size in various rochow contact masses
Authors: Lieske H. , Fichtner H. , Kretzschmar U. , Zimmermann R.
Published: January 2005

Various Rochow contact masses have been characterized by catalytic tests as well as by X‐ray diffraction with respect to η‐Cu3Si percentage and particle size. The presence of η‐Cu3Si in the contact masses is neither a necessary nor a sufficient precondition of catalytic activity, but a certain contribution of dispersed η‐Cu3Si to the activity cannot be excluded. The results can be explained consistently by assuming highly dispersed or even two‐dimensional Cu‐Si species, not detectable by X‐rays, as catalytically active species. The promoters zinc, antimony and tin do not significantly change the percentage and particle size of η‐Cu3Si.
Breakage of λ‐DNA by inorganic tin and organotin compounds as environmental pollutants
Authors: Hamasaki Tetsuo , Sato Takahiko , Nagase Hisamitsu , Kito Hideaki
Published: January 2005

In proportion to the environmental pollution problems caused by organotin compounds, the genotoxicities of tin compounds in the environments have become of interest so as to estimate their safety in recent years. In this work, isolated λ‐DNA (double‐strand DNA) was incubated with inorganic tin(II) and tin(IV) and five organotin compounds [n‐butyltin trichloride, di(n‐butyltin) dichloride, methyltin trichloride, dimethyltin dichloride and trimethyltin chloride] in reaction systems both with and without hydrogen peroxide (H2O2) content. The tin compounds tested in this study did not induce DNA breakage in the absence of hydrogen peroxide. Divalent inorganic tin (SnCl2) and tetravalent inorganic tin (SnCl4) caused DNA breakage in the presence of hydrogen peroxide (10 mM), and the DNA damage activity of inorganic tin was much more potent in divalent inorganic tin (SnCl2) than in tetravalent inorganic tin (SnCl4). Divalent inorganic tin (SnCl2) induced DNA breakage in a concentration‐dependent fashion at concentrations greater than 0.1 mM of SnCl2 in the presence of hydrogen peroxide (10 mM). DNA breakage was not caused by n‐butyltin compounds and methyltin compounds either in the presence or in the absence of hydrogen peroxide.
A new procedure for the speciation of mercury in water based on the transformation of mercury (II) and methylmercury (II) into stable acetylides followed by HPLC analysis
Authors: Fabbri Daniele , Vassura Ivano , Lombardo Marco , Trombini Claudio
Published: January 2005

Conversion of mercury(II) and methylmercury(II) species dissolved in water into di(phenylethynyl)mercury and methyl(phenylethynyl) mercury takes place in satisfactory yield under alkaline conditions by stirring the aqueous solution with phenylacetylene at room temperature. Mercury speciation is simply obtained by HPLC analysis of the two organometallic species. The presence of heavy metals such as copper(II), zinc(II), cadmium(II) and lead(II) in concentrations 10000 times higher than mercury is tolerated, while little interference is displayed by humic acids and cysteine. Seawater samples can also be analysed following a properly adapted procedure.
Programming life histories: An experimental design and initial results
Authors: Denenberg Victor H. , Karas George G. , Rosenberg Kenneth M. , Schell Stephen F.
Published: January 2005

The life experiences of rats were experimentally programmed through the systematic manipulation of several social and stress variables. These were (1) infantile handling vs. no handling of the mothers of the subjects, (2) infantile handling vs. no handling of the subjects, (3)rearing of the subjects in either a maternity cage or a free environment between birth and weaning, (4) rearing of the subjects in either a laboratory cage or a free environment between weaning and 42 days of age, and (5) presence or absence of a stress experience (shuttlebox avoidance learning at 70 days of age, or food and water deprivation at 100 days) in adulthood. Test measures included open‐field performance and shuttlebox learning at 70 and 190 days of age.

Open‐field activity was increased by handling pups in infancy and by rearing pups in a free environment between birth and weaning, whereas it was decreased by food and water deprivation at 100 days. Postweaning free‐environment experience improved avoidance learning performance. A number of interactions were significant, most of which involved the three preweaning variables of Mother Handling, Offspring Handling, and Preweaning Housing.
Relationship of age at eye opening to first optokinetic response in deermice (Peromyscus)
Authors: Vestal Bedford M. , King John A.
Published: January 2005

The relationship between visual development and age at eyelid separation was studied in three stocks of Peromyscus maniculatus bairdi, two stocks of P.m. gracilis, P. polionotus, and P. eremicus. The maniculatus subspecies had each been selectively bred for early and late age at eye opening. Mice were tested in a transparent chamber suspended within a rotating drum, which was lined with alternating 3/4‐in. black and white vertical stripes. Beginning within 8 hr of eye opening, each mouse was given 5, 15 sec trials daily, until it responded. Criterion of vision was an optokinetic response in 2 of the 5 trials. Of 75 mice tested, only the early eye opening selected line of P. m. bairdi failed to respond on the day of eye opening. The results indicate that Peromyscus can see conspicuous environmental features at the age of eyelid separation. The delayed optokinetic response in the early selected bairdi line, requiring an average of 2.4 additional days of maturation, indicates the genetic independence of eyelid separation and visual development. The same line did not respond significantly earlier than wild type bairdi, indicating that the extra visual experience afforded by early eye opening did not increase the rate of maturation of the system (s) governing the optokinetic response.
The development of visually evoked electrocortical responses in the rat
Authors: Rose Guenter H.
Published: January 2005

The development of electrocortical responses evoked by brief, focused monocular light stimulation was studied in 35 lightly anesthetized albino rat pups (Sprague‐Dawley strain) between birth and 35 days of age. A definite sequence of waveform changes occurred during maturation. The initial response at 10 to 11 days of age consisted of a long latency, negative wave. Subsequently, at approximately 12 days of age, a shorter latency, positive‐negative complex appeared. The initial, long latency, negative wave decreased rapidly in latency over the next few days until it coalesced with the negative component of the shorter latency, positive‐negative complex at about 15 days of age, resulting in a biphasic positive‐negative wave similar to that recordable in the adult rat. These results are compared and contrasted with a similar sequence observed in the developing kitten, and are discussed in terms of structural, electrophsiological, and behavioral maturation.