bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fluorescent humic substances and blackfoot disease in Taiwan
Authors: Lu Fung‐Jou 
Published: December 2004

AbstractBlackfoot disease is endemic in Chia Yi and Tainan Counties in south‐western Taiwan. Arsenic present in the drinking water taken from wells has been blamed for causing this disease. The discovery in 1975 of fluorescent compounds in these well waters led to the isolation of these substances, to their identification as humic substances containing a large number of elements (among them arsenic), and to the development of an animal model for blackfoot disease. Mice receiving aqueous solutions of these fluorescent substances at a daily dose of 5 mg per 20 g body mass for at least 22 days developed blackfoot and blacktail disease. Work with these fluorescent substances, their chemical properties, and their biological actions is reviewed.
Synthesis, characterization and in vitro antitumour activity of a series of substituted 2,2‐di‐n‐butyl‐4‐oxo‐benzo‐1,3,2‐dioxastannins
Authors: Bouǎlam Mohammed , Willem Rudolph , Gelan Jan , Sebald Angelika , Lelieveld Peter , de Vos Dick , Gielen Marcel 
Published: December 2004

AbstractThe characterization by 1D and/or 2D 1H NMR, 13C NMR, 119Sn NMR, Mössbauer and mass spectrometry of a series of di‐n‐butyltin derivatives of 3‐, 4‐, and 5‐methyl‐, 3‐, 4‐, and 5‐methoxy‐, 4‐ and 5‐amino‐substituted, and 3,5‐diiodo‐salicyclic acids is described. Their NMR spectra suggest that they are present as dimers in CDCl3 solution, like the di‐n‐butyltin derivative of unsubstituted salicyclic acid. This has been confirmed by the observation of mixed dimers. The insoluble derivatives have been characterizerd by solid state cross polarization/magic angle spinning (CP/MAS) 13C and/or 119Sn NMR, Mössbauer and mass spectroscopy. These compounds are characterized in vitro by a lower inhibition dose than cis‐platin or etoposide against a series of five human cell lines.
Influence of the ligand structure on SLP‐catalysed hydroformylation of propene
Authors: Hjortkjaer Jes , Heinrich Bernd , Čapka Martin 
Published: December 2004

AbstractHydroformylation of propene was studied at 90–120°C and 3–10 atm. The catalyst was hydrido‐(carbonyl)tris(triphenylphosphine)rhodium [H(CO)Rh(PPh3)3] supported on silica, in an excess of a liquid phosphine (P) ligand as solvent. The following series of ligands (P) was synthesized and studied in this application: CH3(CH2)nPPh2 (n = 3, 7, 17), (c – C6H11)xPPh3−x (x = 0, 1, 2) and also unsaturated allyl‐ and poly(butadienyl)‐diphenylphosphines. The activity and regioselectivity of the catalysts are discussed in terms of the mobility and coordination ability of the ligands used. With the same electron density of the phosphorus atom, the activity of the catalysts increases with the mobility of the ligands. On the other hand, given the same mobility of the ligand, a lower electron density on phosphorus results in increased catalytic activity.
Useful and accessible organometallic precursors for preparation of zinc sulfide and indium sulfide thin films via solution pyrolysis (printing) method
Authors: Nomura Ryǒki , Konishi Kazuhisa , Futenma Satoshi , Matsuda Haruo 
Published: December 2004

AbstractPolycrystalline β‐zinc sulfide thin films were prepared by solution pyrolysis of an ethylzinc isopropylthiolate–zinc bis(dibutyldithiocarbamate) combined precursor (EtZnSiPr–Zn(S2CNnBu2)2) in chloroform solution on glass or silicon(111) substrates at 300°C. Homogeneous but amorphous indium sulfide thin films were obtained from butylindium bis(isopropylthiolate) (nBuInSiPr2) in P‐xylene on these substrates at 300°C similarly. The sulfide thin films obtained were characterized by means of X‐ray photoelectron spectroscopy (XPS), X‐ray fluorescence Microanalysis, scanning electron microscopy (SEM) and optical band gap measurements.
Studies of the uptake and binding of trace metals in fungi. Part II. Arsenic compounds in Laccaria amethystina
Authors: Byrne Anthony R , Tušek‐Žnidarič Magda , Puri Bal K , Irgolic Kurt J 
Published: December 2004

AbstractCaps of the edible mushroom Laccaria amethystina collected during September and October at forested sites in the vicinity of the town of Domzale in Central Slovenia, Yugoslavia, were found by neutron activation analysis (NAA) and hydride generation to have total arsenic concentrations between 109 and 200 mg As kg−1 (dry mass). The extraction of fresh, frozen or freeze‐dried caps with cold Tris buffer at pH 7.6, or with boiling water, transferred 60–70% of the arsenic into the aqueous phase. Sephadex gel permeation chromatography indicated that the arsenic compounds in these extracts were not associated with proteins or other organic compounds of molecular mass larger than 4000 Dal.Cation‐exchange chromatography coupled with NAA, hydride generation, and reverse‐phase chromatography with arsenic‐specific detection (HPLC ICP) showed that dimethylarsinic acid is the major arsenic compound in the extracts. Methylarsonic acid and arsenate account for no more than 10% each of the total arsenic.
A synergistic organoiron flame‐retarding/smoke‐suppressing system for ABS
Authors: Carty P , White S 
Published: December 2004

AbstractCommercial acrylonitrile butadiene styrene (ABS) polymers are among the most flammable of the currently available range of thermoplastic materials. In addition to having a rather low limiting oxygen index (LOI) value in the range 18.3–18.8, ABS polymers also produce compious amounts of smoke and hazardous gases when burnign in the air. In a recent study directed towards preparing and evaluating compounds which would simultaneously reduce the flammability and smoke produced from burning thermoplastic polymers, a synergistic flame‐retarding/smoke‐suppressing system based on organoiron compounds has been produced, which when properly compounded into ABS/PVC [poly(vinyl chloride)] blends more than doubles the LOI nad at the same time reduces smoke production significantly.
Determination of arsenic and arsenic compounds in natural gas samples
Authors: Irgolic Kurt J , Llger Drew , Zingaro Ralph A , Spall Dale , Puri B K 
Published: December 2004

AbstractOrganic arsenic compounds (trialkylarsines) present in natural gas were extracted by 10 cm3 of concentrated nitric acid from 1 dm3 of gas kept at ambient pressure and temperature. The flask containing the gas and the acid was shaken for 1 h on a platform shaker set at the highest speed. The resulting solution was mixed with concentrated sulfuric acid and heated to convert all arsenic compounds to arsenate. Total arsenic was determined in the mineralized solutions by hydride generation. The arsenic concentrations in natural gas samples from a number of wells in several gas fields were in the range 0.01–63 μ As dm−3. Replicate determinations of arsenic in a gas sample with an arsenic concentration of 5.9 μ dm−3 had a relative standard deviation of 1.7%. Because of the high blank values, the lowest arsenic concentration that could be reliably determined was 5 ng As dm−3 gas. Analysis of nonmineralized extracts by hydride generation identified trimethylarsine as the major arsenic compound in natural gas. Low‐temperature gas chromatography‐mass spectrometry showed more directly than the hydride generation technique, that trimethylarsine accounts for 55–80% of the total arsenic in several gas samples. Dimethylethylarsine, methyldiethylarsine, and triethylarsine were also identified, in concentrations decreasing with increasing molecular mass of the arsines.
Leaching of organotin compounds from poly(vinyl chloride) (PVC) material
Authors: Quevauviller Ph , Donard O F X , Bruchet A 
Published: December 2004

AbstractThe release of mono‐and di‐butyltin species (MBT and DBT) in water after leaching of five different poly(vinyl chloride) (PVC) materials was investigated under mild conditions over a period of one month in batch reactor systems. Results showed that inorganic tin, MBT and DBT compound were released from the material tested under experimental static leaching conditions. The total amount of inorganic tin and organotin compounds observed upon leaching varied considerably from one PVC material to another.
The use of metallocenic esters of n‐hydroxysuccinimide for metallohapten synthesis
Authors: Lavastre I , Besançon J , Brossiert P , Moise C 
Published: December 2004

AbstractDifferent organometallic markers have been described in a new technique for the labelling of many drugs. Thus metallocenic esters of
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[M = (;CO)3CrC6H5; (;CO)3CrC6H5(;CH2)3; η‐C5H5FeC5H4; (;CO)3MnηC5H4; (;CO)3MnηC5H4COCH2CH2; ηC5H4(;ηC5H5)Co+PF−6] react with primary or secondary amine drugs [DRUGNHR] for a psychostimulant drug: amphetamine; tricyclic antidepressants—desipramine and nortriptyline; a vasodilator—histamine; an adrenergic substance—norfenefrine; and for a central stimulant—meth‐amphetamine, to give the metallohaptens MCON(;R)—DRUG. All these compounds have been fully characterized by different analytical methods and have potentialities for biological assays. This synthetic route was found better than one presented previously which utilized the metallocenic acid chloride MCOCI as intermediate, and could be proposed as a general synthetic route for labelling biological compounds which possess an amino group.
Determination of butyltin species by GC/atomic emission spectroscopy
Authors: Scott B F , Chau Y K , Rais‐Firouz A 
Published: December 2004

AbstractA commercially available atomic emission detector coupled to a capillary column‐containing gas chromatograph (;GC/AE) was utilized to detect organotin compounds. The response for tin was found to be dependent on the flow rate of the make‐up gas. At flow rates of 174 cm3 min−1, 6 × 10−12 g of tin could be detected. Lower flow rates decreased the sensitivity. Response curves for two different pressures were established and both plots exhibited curvature at low concentrations. Extracted fish and sediment samples were analysed on the GC/AE system. The technique is element‐specific. The presence of tin compounds could be confirmed by examining the emission spectra taken at the retention time of the peak.
Catalytic ethylation of alkylbenzenes at high pressure
Authors: Assadourian L , Gau G 
Published: December 2004

AbstractStudy of the catalytic ethylation of p‐t‐butyltoluene in the presence of organosodium compounds, and of toluene in the presence of organopotassium compounds, was carried out at an ethylene pressure of 40 bar.Various yields of different products were obtained after 23 h of reaction in the presence of different tertiary polyamines used to complex and solubilize the organoalkali compounds.A higher initial ethylation rate was observed in the presence of organosodium than in the presence of organopotassium species. However, the thermal stability of organopotassium species being higher, much higher yields were observed in their presence in catalytic ethylation reactions than those observed previously.The results obtained concerning metallation or ethylation of hindered alkylaromatics may be interpreted by an anionic mechanism and the activation by a steric effect.
Synthesis, characterization and in vitro antitumour properties of complexes of bis(alkoxycarbonylmethyl)tin dibromides with bidentate nitrogen ligands
Authors: Zhang Zhengquan , Pan Huade , Hu Chun , Fu Fangxin , Sun Yunhong , Willem Rudolph , Gielent Marcel 
Published: December 2004

AbstractThe synthesis and characterization of 10 new bis(;alkoxycarbonylmethyl)tin dibromides and of 14 of their complexes with bidentate nitrogen ligands (;bipyridyl, 1,10‐phenanthroline and 5‐nitro‐1, 10‐phenanthroline) are described. Their proton NMR spectra are discussed. Their in vitro antitumour activity against two human cancer cell lines, MCF‐7 and WiDr, is low compared to antitumour drugs used clinically.
Synchrotron radiation‐stimulated photochemical reaction and its application to semiconductor processes
Authors: Urisu Tsuneo , Takahashi Jun‐Ichi , Utsumi Yuichi , Akazawa Housei 
Published: December 2004

AbstractRecent results are reviewed on synchrotron radiation (SR)‐excited photochemical reaction studies aimed at applications to semiconductor processes. Valence or core electronic excitations induced by SR irradiation and ensuing chemical reactions are classified and characterized by rate equations. Unique material selectivity in etching has been found. SiO2 has been found to evaporate by SR irradiation and this phenomenon can be applied to the low‐temperature surface cleaning of silicon. In the epitaxial growth of Silicon by ultrahighvacuum chemical vapor deposition using Si2H6, SR irradiation significantly lowers growth temperature beyond the low‐temperature limit of thermal reaction. Lowering of the operating temperature by SR irradiation is especially effective in applications to the atomic layer epitaxial growth of silicon. The layer‐by‐layer process has been successfully demonstrated, confirming self‐limiting adsorption of SiH2Cl2 and ensuring surface reactivation by SR irradiation.
Photo‐Absorption and photochemical decomposition of copper and alkaline‐earth ß‐diketonates as source gases of high‐Tc superconducting films
Authors: Hashimoto Takuya , Kitazawa Koichi , Nakabayashi Masaaki , Shiraishi Tadashi , Suemune Youichi , Yamamoto Takakazu , Koinuma Hideomi 
Published: December 2004

AbstractFor low‐temperature deposition of oxide films relating to Bi‐Sr‐Ca‐Cu‐O superconductors, photo‐absorption and ‐decomposition properties were examined with respect to copper and alkaline‐earth ß‐diketonates. It was confirmed that all ß‐diketonates examined were promising as source materials for photochemical vapour deposition (photo‐CVD) using a low‐pressure mercury lamp, in view of their large light absorption coefficients at wavelength 254 nm. The light irradiation was effective for the formation of highly crystalline oxide films at temperatures below 600 °C. By combining two sources, Ca2CuO3 and SrCuO2 films were prepared. Photo‐CVD of c‐axis oriented Bi2Sr2CuOx film was achieved by the irradiation of ternary sources of Bi(C6H5)3 and strontium and copper ß‐diketonates at 500 °C.
The epitaxial growth of gaas using alkylarsine: Part 2. molecular orbital calculation
Authors: Kikuzono Y , Maeda T 
Published: December 2004

AbstractSemi‐empirical molecular orbital calculations were carried out for the compounds (C2H5)3As, (C2H5)3Ga and RAsH2 (R = C2H5, i‐C3H7, i‐C4H9, and t‐C4H9) by using the CNDO/2‐U program, and their capability of β‐elimination reaction is compared on the basis of the torsion energy to the transition state, electrostatic interactions and orbital overlapping between the central atom and the β‐hydrogen, and bond order of the metal‐carbon, and carbon‐hydrogen bond. In the comparison of (C2H5)3As with (C2H5)3Ga, we found that the β‐elimination of (C2H5)3As could hardly be expected to take place in the thermal decomposition. The capability of β‐elimination would be smaller in C2H5AsH2 than that in (C2H5)3As. Moreover when the ethyl group is replaced by a t‐butyl group in RAsH2, the β‐elimination reaction appears to become more difficult and a large possibility for a radical process is suggested.
Biomonitoring in the mercury‐contaminated Wabigoon–English–Winnipeg river (Canada) system: selecting the best available bioindicator
Authors: Parks J W , Craig P J , Neary B P , Ozburn G , Romani D 
Published: December 2004

AbstractSeveral organisms used for biomonitoring in the mercury‐contaminated Wabigoon–English River System, Ontario, Canada (sport fish, forage fish, crayfish and others) were examined for their utility as bioindicators. Causes for spatial and temporal variability in mercury concentrations in biota are reviewed. The significance of intertrophic and intratrophic biotic relationships is evaluated on both a site‐specific and intersite basis. Larger mature fish are the most effective integrators as these organisms are the most buffered from site‐specific and seasonal variations in mercury concentrations and bioavailability. Where there are no physical barriers preventing movement of biota between contaminated and uncontaminated parts of the watercourse, younger, smaller organisms can better ‐ ical zones of contamination because of their restricted range. Because many organisms can provide information on mercury contamination, the choice of the most suitable indicator depends upon the purpose of the study, the pharmacokinetics of mercury uptake by the organisms in question, and the chemodynamics of methyl and inorganic mercury species in the field.
Alkane activation by homogeneous palladium complexes
Authors: Beattie James K , Masters Anthony F , Sparkes Meredith L 
Published: December 2004

AbstractThe conversion of adamantane exclusively to 1‐adamantyl trifluoroacetate in a refluxing trifluoroacetic acid solution of palladium acetate at 1 atm of air or nitrogen was confirmed. The conversion can be made quantitative. The 1‐adamantyl trifluoroacetate was hydrolysed to yield 1‐adamantanol in 90% isolated yield. The adamantane functionalization is accompanied by concomitant formation of a palladium mirror.
Speciation and GC retention indices of some organotin compounds in water
Authors: Rosales Daniel , Pablos Fernando , Marr Iain L 
Published: December 2004

AbstractAnalytical methods have been developed for the quantitative determination of Bu4Sn, Bu3Sn+, Bu2Sn2+, BuSn3+, Me3BuSn, Me2Bu2Sn, MeBu3Sn, MeBuSn2+, Me2BuSn+ and MeBu2Sn+ in water. Organotin compounds are extracted from water with tropolone at 0.1 % in n‐pentane, derivatized with n‐pentylmagnesium bromide and determined by gas chromatography with flame photometric detection or flame ionization detection. Absolute detection limits are 0.05‐0.12 ng and 1.2‐13 ng as tin, respectively. The method was applied to the analysis of spiked tap‐water containing 0.3‐1000 ng cm−3 of each of the organotin compounds.
Synthesis and spectroscopic characterization of diethyltin (IV) derivatives of dipeptides: Crystal and molecular structure of diethyltin glycyltrosinate
Authors: Vornefeld Michael , Huber Friedo , Preut Hans , Ruisi Giuseppe , Barbieri Renato 
Published: December 2004

AbstractDipeptide complexes of the diethyltin(IV) moiety, Et2SnL, have been synthesized, H2L being glycylglycine (H2GlyGly), glycylalanine (H2GlyAla), alanylalanine (H2AlaAla), glycylvaline (H2GlyVal), valylvaline (H2ValVal), glycylmethionine (H2GlyMet), glycyltyrosine (H2GlyTyr). The crystal and molecular structure of the complex Et2SnGlyTyr has been determined by singlecrystal X‐ray diffraction. It consists of monomeric units, with the tin atom having a considerably distorted trigonal bipyramidal environment. The dipeptide acts as a tridentate ligand bonding the tin of the C2Sn fragment (equatorial carbon atoms) with the peptide nitrogen atom (equatorial) and axial (monodentate) carboxyl oxygen and amino nitrogen atoms, into a monomeric unit. Bond lengths and angles are reported. Infrared spectroscopic data show the occurrence of monodentate carboxyl in all solid compounds, as well as in methanol solutions of some representative complexes. 119Sn Mössbauer spectroscopic data, and their rationalization through point‐charge model (literal version) calculations of the parameter nuclear quadrupole splitting (ΔE) confirm the general occurrence of trigonal bipyramidal structures of the Et2SnGlyTyr type, in the solid state, and give evidence of variations of the CSnC angle in the individual Et2SnL species. Monomers occur in CH3OH solution as suggested by osmometric measurements. 13C and 119Sn NMR spectroscopic data in CD3OD show the persistence of the solid‐state structures also in the solution phase, where the order of magnitude of the CSnC angles, as estimated from the coupling constants |1J(119Sn,13C)|, corresponds to that shown by Et2SnGlyTyr in the solid state. 119Sn Mössbauer parameters of Et2SnGlyGly in frozen CH3OH solution are consistent with the assumptions from the NMR studies.
Anmerkungen zum Aufsatz „Wozu Philosophie der Chemie?”︁
Authors: Stork Heinrich , Metz Peter , Janich Peter 
Published: December 2004

Abstract„Der Dialog ist eröffnet”︁ – mit dieser Aufforderung schloß das Editorial zum oben genannten Beitrag von Peter Janich in Heft 3/94 der „Chemie in unserer Zeit”︁. Danke an Heinrich Stork und Peter Metz, die in Form von Leserbriefen zum Dialog beigetragen haben. Ihre Bemerkungen und die Antworten von Peter Janich sind im folgenden wiedergegeben.
The rostral projections of the primate vestibular nuclei: An experimental study in macaque, baboon and chimpanzee
Authors: Tarlov Edward 
Published: December 2004

AbstractThe ascending projections of the vestibular nuclei were studied with the selective silver methods of Nauta‐Gygax (Nauta,'57), Voneida ('67) and Fink et al. ('67) in macaque, baboon and chimpanzee. Degenerated axons pass from lesions in the vestibular nuclei into the medial medullary and pontine tegmentum bilaterally, the abducens nuclei, the contralateral vestibular complex and in the medial longitudinal fasciculus to the nuclei of the III and IV nerves. A few fibers pass rostral to the oculomotor complex into the interstitial nuclei of Cajal, the nuclei of Darkshewitsch and the nuclei of the posterior commissure. No degenerated fibers originating in vestibular nuclear lesions were observed to ascend rostral to the level of the posterior commissure. Degenerated fibers rostral to this level could be traced, in sagittal, horizontal and frontal sections, to incidental damage to the superior cerebellar peduncle and the posterior column nuclei. Damage to the acoustic striae produced ascending degeneration in the auditory system, but this did not pass rostral to the inferior colliculus. The incidentally damaged tracts could be seen, in sections in three planes, to be separate in their course and terminations from the fibers ascending from the vestibular nuclei in the medial longitudinal fasciculus.The experimental evidence lends no support to the supposition that direct secondary vestibular connections to the diencephalon exist. Previous anatomical descriptions of direct vestibulothalamic connections appear to result from failure to discriminate between fibers originating in the vestibular nuclei and fibers arising in adjacent regions. Vestibular impulses reaching the diencephalon must pass over third or higher order neurons after synapse at lower levels.
Degeneration and regeneration of hypothalamic nerve fibers in the neurohypophysis after pituitary stalk section in the ferret
Authors: Adams James Hume , Daniel Peter Maxwell , Prichard Marjorie Mabel Lucy 
Published: December 2004

AbstractTransection of the pituitary stalk caused rapid and severe degeneration of the hypothalamo‐hypophysial nerve tract distal to the operation site. When a barrier had been inserted to prevent reunion of the stalk this degeneration was permanent. All nerve fibers and stainable neurosecretory material (NSM) disappeared. When a barrier was not used the initial degeneration was followed by regeneration. From two weeks after operation new nerve fibers from the hypothalamus, carrying NSM, were found growing through the scar and down the degenerated lower infundibular stem towards the infundibular process, which was fully re‐innervated by the end of a year. The re‐innervated lower infundibular stem contained an abnormally large amount of NSM. In many cases an outgrowth of nerve fibers from the regenerating tract had invaded the rostral end of pars distalis; these also were surrounded by NSM. Another unusual feature often seen was an ectopic infundibular process which had developed not far below the site of operation.In its capacity for vigorous regeneration the hypothalamo‐hypophysial nerve tract appears to be unique among tracts of the central nervous system. It is suggested that this regenerative capacity may be related to the fact that this tract is composed of non‐myelinated nerve fibers.