bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of phosphate on arsenate inhibition in a marine cyanobacterium, Phormidium sp.
Authors: Takahashi Akira , Kawakami Hidekazu , Bada Akira , Okonogi Yasutaka , Matsuto Shigeki 
Published: December 2004

AbstractThe effect of arsenate on cells of a marine cyanobacterium, Phormidium sp. preliminarily starved for phosphate for a week was studied. Cells were harvested and cultured in artificial seawater containing various concentrations of arsenate and phosphate. Arsenate at concentrations above 30 mg As dm−3 inhibited biosynthesis in the cells and consequently, growth when incubated without phosphate in the medium. On the contrary, phosphate at 50 μmol dm−3 was sufficient for apparently complete cancellation of the inhibitory effects of arsenate at concentrations up to 150mg As dm−3. Study of the carbohydrate metabolism revealed an intense inhibition by arsenate on turnover of carbohydrate to other cell components in the phosphae‐depleted cells. This resulted in a color change of the cells from blue–green to yellowish. The synthesis of carbohydrate itself was also inhibited by arsenate. Arsenate incorporation into cells was clearly inhibited by phosphate in the medium, suggesting that arsenate competes with phosphate for entry into cells. In addition, arsenate incorporated in cells could not inhibit the incorporation of phosphate and subsequent growth of cells on phosphate. These observations indicate that arsenate can act as a poisonous substitute for phosphate in the cells but, once incorporated into the phosphate‐replete cells, it no longer has an inhibitory effect. The inhibitory effects of arsenate seem to be mainly related to ATP synthesis in the photosynthetic system.
The exploitation of new synthetic reactions by means of rare earth metals
Authors: Takaki Ken , Fujiwara Yuzo 
Published: December 2004

AbstractThis review deals with lanthanoid mediated organic reactions investigated by the authors. The scope of the lanthanoid‐mediated reactions are discussed under the following topics:

Reactions of Yb metal umpoled diaryl ketones with electrophiles;
Reactions of Yb metal with imines;
Reactions of Yb metal with CC multiple bonds;
Reactions of Sm metal with nitroarenes;
Reactions of Yb metal with α,β‐unsaturated carbonyl compounds;
Reactions of a PhYbI σ‐complex;
Reactions of LnCl3 as Friedel‐Crafts catalyst.
Structure–activity relationships for organotin compounds on the red killifish Oryzias latipes
Authors: Nagase Hisamitsu , Hamasaki Tetsuo , Sato Takahiko , Kito Hideaki , Yoshiokat Yoshitada , Ose Youki 
Published: December 2004

AbstractThe LC50 values of a series of 29 organotin compounds were determined for the red killifish (Oryzias latipes) according to an OECD test guideline. Their toxicities varied from 10−1 to 10−5 mmol dm−3 in five orders of magnitude. In this paper a quantitative structure‐activity relationship (QSAR) study of these organotin compounds was carried out using physicochemical and topological parameters as independent variables. These parameters were found not to be good descriptors for estimating the LC50 values. However, when the term index Value (IV), which is created as a new parameter and is defined by the number of phenyl or alkyl groups attached to the tin atom, was used, excellent regression equations to predict the toxicities of organotin compounds were obtained and a multiparametric relationship including IV, Information Index (IWD and Mean Information Index (IWD)) showed the best correlation.
X‐Ray photoelectron spectroscopy and electrical conductivity studies of metallophthalocyanine sheet polymers
Authors: Nalwa Hari Singh 
Published: December 2004

AbstractThe X‐ray photoelectron spectroscopy (XPS) technique has been used to characterize metallophthalocyanine sheet polymers having peripheral carboxyl groups. A comparative analysis of the XPS and electrical conductivity data of metal‐free, and nickel‐ and copper‐containing, phthalocyanine sheet polymers has been described. Metallophthalocyanine sheet polymers exhibited a maximum conductivity of about 1 S cm−1 on pyrolysis.
Organometallic chemistry related to applications for microelectronics in Japan
Authors: Sato Hiroyasu 
Published: December 2004

AbstractThis is meant to be a brief overview of the developments of research activities in Japan on organometallic compounds related to their use in electronic and optoelectronic devices.The importance of organometallic compounds in the deposition of metal and semiconductor films for the fabrication of many electronic and opto‐electronic devices cannot be exaggerated. Their scope has now extended to thin‐film electronic ceramics and high‐temperature oxide superconductors. A variety of organometallic compounds have been used as source materials in many types of processing procedures, such as metal–organic chemical vapor deposition (MOCVD), metalorganic vapor‐phase epitaxy (MOVPE), metal–organic molecular‐beam epitaxy (MOMBE), etc. Deposited materials include silicon, Group III–V and II–VI compound semiconductors, metals, superconducting oxides and other inorganic materials.Organometallic compounds are utilized as such in many electronic and optoelectronic devices; examples are conducting and semiconducting materials, photovoltaic, photochromic, electrochromic and nonlinear optical materials.This review consists of two parts: (I) research related to the fabrication of semiconductor, metal and inorganic materials; and (II) research related to the direct use of organometallic materials and basic fundamental research.
XPS study on early stages of heat deterioratin of silicon‐containing aromatic polymide film
Authors: Sugitani H , Kikuchi T , Sugimoto Y , Saitou T 
Published: December 2004

AbstractEarly stages of heat deterioration of some siliconcontaining aromatic polyimide thin films with disiloxane groups (I) in their main chains were studied with XPS. It was found that the thermal decomposition of silicon‐containing aromatic polyimides takes place at lower temperatures than those not modified with silicon. The low thermal stabilities observed are explained by the easier decomposition of silicon–carbon bonds (e.g. silicon–methylene, silicon–aryl) than other bonds (e.g. carbon–carbon, carbon–oxygen). Particularly, silicon–methylene bonds (II) readily undergo thermal oxidative decomposition and start to decompose at 350°C under aerobic conditions. This starting temperature of thermal decomposition is lower by 100°C than that of the corresponding polyimide not modified with silicon. In the case of polyimide incorporating silicon–aryl bonds (III) instead of silicon–methylene bonds, the decrease in the thermal decomposition temperature is as small as 50°C, and decomposition under aerobic conditions starts at 400°C.
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The epitaxial growth of AlGaAs using highly purified trimethylaluminum
Authors: Maeda T , Hata M , Isemura M , Yako T 
Published: December 2004

AbstractHighly purified trimethylaluminum [(CH3)3Al] was prepared by reducing the contamination of volatile impurities such as organic silicon and dimethyl‐aluminum methoxide [(CH3)2AlOCH3]. The concentration of methoxy group in (CH3)3Al was found to decrease considerably when (CH3)2Al was distilled in the presence of aluminum trihalide. Among the halides, purification efficiency increased in the order I>Br>Cl.High‐quality AlGaAs layer and AlGaAs/GaAs modulation doped structures were grown by organometallic vapor‐phase epiloxy (OMVPE) using the purified (CH3)3Al. Their electrical properties were discussed in relation to the volatile impurity in the source gas.
Synthesis of poly‐yne polymers containing transition metals, disilane, disiloxane and phosphine groups in the main chain
Authors: Kotani S , Shiina K , Sonogashira K 
Published: December 2004

AbstractThe synthesis and characterization of metal poly‐yne polymers containing disilane, disiloxane and phosphine groups in the main chain are described. The platinum and palladium poly‐yne polymers were synthesized by polycondensation reactions between a metal chloride and an α, ω‐bisethynyl complex in amines in the presence of cuprous iodide as a catalyst. The nickel poly‐yne polymers were synthesized by an alkynyl ligand exchange reaction between a nickel acetylide and an α, ω‐bisethynyl complex in diethylamine in the presence of cuprous iodide as a catalyst. The reaction of the platinum poly‐yne polymer, containing disiloxane groups in the main chain, with copper (I) salts afforded adducts of η‐2‐bonded σ‐acetylide polymer complexes. The reactions of the palladium poly‐yne polymer, containing phosphine groups in the main chain, with transition‐metal carbonyl complexes afforded polymer complexes which have phosphorus in the main chain‐transition‐metal bonds. A concentrated solution of the platinum poly‐yne polymer containing disiloxane groups in the main chain forms a lyotropic liquid crystal in dichloromethane or 1, 2‐dichloroethane.
Conversion of arsenobetaine to dimethylarsinic acid by arsenobetaine‐decomposing bacteria isolated from coastal sediment
Authors: Hanaoka Ken'Ichi , Tagawa Shoji , Kaise Toshikazu 
Published: December 2004

AbstractArsenobetain [(CH3)3As+CH2COO‐]‐containing growth media (1/5 ZoBell 2216E and solution of inorganic salts) were inoculated with two bacterial strains, which were isolated from a coastal sediment and identified as members of the Vibro‐Aeromonas group, and incubated under aerobic and anaerobic conditions. Arsenobetaine was converted to a metabolite only under aerobic conditions. This arsenic metabolite was identified as dimethylarsinic acid [(CH3)2AsOOH] by hydride generation/cold trap/GC MS/SIM analysis and high‐performance liquid‐chromatographic behaviour. The conversion pattern shown by these arsenobetaine‐decomposing bacteria (that is, arsenobetaine → dimethylarsinic acid) was fairly different from that shown by the addition of sediment itself as the source of arsenobetaine‐decomposing micro‐organisms (that is, arsenobetaine → trimethylarsine oxide → inorganic arsenic). This result suggests to us that various micro‐organisms, including the arsenobetaine‐decomposing bacteria isolated in this study, participate in the degradation of arsenobetaine in marine environments.
Structural effects on the antitumour activity of organotin compounds 2. Further diaryltin dichloride complexes with nitrogen‐donor ligands
Authors: Biddle Brian N , Gray J S 
Published: December 2004

AbstractThe synthesis and investigation of the anti‐tumour activity of a further series of six new diorganotin dichloride complexes Ar2SnCl2.L2, where Ar = 2‐thienyl, 2,4‐dimethoxyphenyl, 4‐methyoxyphenyl, 4‐methylphenyl or 4‐trifluoromethylphenyl and L2 = 2‐(2‐pyridyl)benzimidazole (PBI) or 2‐amino‐methylpyridine (AMP), is reported. One of these complexes was found to be active against P388 lymphocytic leukaemia in mice. The results obtained are in general agreement with previously published work. The activity of the diaryltin dichloride complexes is shown to be dependent on the electronic effect of the aromatic group. The use of PBI as a ligand, however, shows no advantage over other ligands used in the series investigated.
Synthesis, characterization and in vitro antitumor activity of dimethyl‐, diethyl, and di‐t‐butyl‐tin(IV) derivatives of substituted salicylic acids
Authors: Bouâlam Mohammed , Willem Rudolph , Biesemans Monique , Gielen Marcel 
Published: December 2004

AbstractThe synthesis of dimethyl‐, diethyl‐ and/or di‐t‐butyl‐tin(IV) derivatives of substituted salicylic acids of the type a, (X‐Y‐2‐OH‐C6H2COO)2SnR2 (X, Y  H, H; H, 5‐CH3; H, 5‐Cl; H, 5‐F; H, 3‐CH3O; H, 5‐CH3O; 3‐CH3, 6‐(CH3)2CH; 3,5‐[(CH3)2CH]2 and 4,5‐benzo) and b {[R2(X‐Y‐2‐OH‐C6H2COO)Sn]2O}2 (X, Y  H, 3‐CH3O; H, 5‐CH3O: 3‐CH3, 6‐(CH3)2CH; 3,5‐[(CH3)2CH]2 and 4,5‐benzo) is reported. Their characterization by 1H, 13C and 119Sn NMR, Mössbauer and mass spectrometry is described. The in vitro antitumor activity of selected derivatives against two human tumoral cell lines, MCF‐7 and WiDr, is presented.
Structural chemistry of organotin carboxylates XV. Diorganostannate esters of dicyclohexylammonium hydrogen oxalate. Synthesis, crystal structure and in vitro antitumour activity of bis(dicyclohexyl‐ammonium) bisoxalatodi‐n‐butylstannate and bis(dicyclohexylammonium) μ‐oxalatobis(aquadi‐n‐butyloxalatostannate)
Authors: Ng Seik Weng , Kumar Das V. G. , Gielen Marcel , Tiekink E. R. T. 
Published: December 2004

AbstractDicyclohexylamine, oxalic acid dihydrate and di‐n‐butyltin oxide were reacted in 2:2:1 or 2:3:2 stoichiometries in ethanol solution to yield, respectively bis(dicyclohexylammonium) bisoxalatodi‐n‐butylstannate (1) and bis(dicyclohexylammonium) μ‐oxalatobis(aquadi‐n‐butyloxalatostannate) (2); the hydrate was also obtained upon recrystallization of 1 from moist acetonitrile solution. The crystal structures of the two ammonium stannates have been determined at room temperature. In 1, the tin atom in the dianion exists in a skewtrapezoidal bipyramidal geometry with the basal plane being defined by two bidentate oxalate ligands; each ligand forms asymmetric SnO bonds [SnO 2.348(4), 2.110(4) Å and 2.112(4), 2.363(4) Å]. The apical sites are occupied by the two organo groups disposed over the weaker SnO bonds. In 2, the two tin centres of the dianion are connected via a tetradentate oxalate ligand situated about a centre of inversion and each tin atom exists in a pentagonal bipyramidal geometry. The pentagonal plane is defined by four oxygen atoms, two from the central ligand [SnO 2.282(4), 2.473(4)Å] and two from a ‘terminal’ oxalate ligand [SnO 2.239(4), 2.210(4)Å], and the fifth site is occupied by a water molecule of crystallization [SnO 2.422(4)Å]; the apical sites are filled by the n‐butyl groups. Both compounds feature extended hydrogen‐bonded networks involving the oxygen atoms of the dianion and the N‐bound hydrogen atoms. Crystals of 1 are monoclinic, space group P21/n, with cell dimensions a = 13.408(3), b = 22.461(4), c = 13.996(2)Å, β = 100.97(2)°; full‐matrix least‐squares refinement on 3305 reflections with I≥2.5σ(I) converged to R = 0.042 and Rw = 0.046. Crystals of 2 are monoclinic, space group P21/n, a = 13.729(3), b = 14.694(2), c = 14.889(2)Å, β = 104.83(2)º; refinement on 2093 reflections converged to R = 0.030 and Rw = 0.031. The two di‐n‐butylstannates were screened in vitro against the mammary MCF‐7 and WiDr colon carcinoma cell lines, and were found to be as active as cisplatin, a clinically used antineoplastic drug.
Wissenschaft aktuell
Authors: Mayr Herbert , Schultz Günter , Jaenicke Lothar 
Published: December 2004

AbstractMit George A. Olah hat die Königlich Schwedische Akademie der Wissenschaften erstmals und für manche überraschend einen Forscher für Arbeiten auf dem Gebiet organischer Reaktionsmechanismen und reaktiver Zwischenstufen mit dem Nobelpreis ausgezeichnet, eine Ehre, die selbst C. K. Ingold (1893 – 1970), dem Begründer dieser Arbeitsrichtung, versagt blieb. Der Nobelpreis für Medizin und Physiologie ging in diesem Jahr an die beiden US‐Amerikaner Alfred G. Gilman und Martin Rodbell für ihre Arbeiten über die G‐Proteine.
Transneuronal changes in the lateral geniculate nucleus of the squirrel monkey, Saimiri sciureus
Authors: Jacobs Gerald H. 
Published: December 2004

AbstractLong‐term transneuronal changes have been investigated in the lateral geniculate nucleus of the squirrel monkey (Saimiri sciureus). Recent reports that the parvocellular portion of that nucleus is laminated in typical primate fashion are verified. Measurements of changes in cell size indicate that, (a) cells in the parvocellular layers show greater shrinkage than do cells in the magnocellular layers and, (b) there is little change in cell size for enucleation terms of one versus two years. Measurements are also presented which suggest that lateral geniculate cells retaining retinal input in the monocular squirrel monkey show an increase in cross‐sectional area so that enucleation may lead to both atrophic and hypertrophic changes.
Electron microscopical study on the development of the satellite cell sheath in spinal ganglia
Authors: Pannese Ennio 
Published: December 2004

AbstractThe spinal ganglia of the fowl have been studied from the third incubation day to the adult.The neuroblasts are the first cells that differentiate in the ganglionic anlage. Satellite cells, probably arising from the undifferentiated elements scattered among the neuroblasts, become detectable during the fifth incubation day. They appear starshaped with attenuated cytoplasmic expansions intervening between adjacent neuroblasts. At this time the neuroblasts largely outnumber the satellite cells.From the sixth incubation day connective tissue spaces, appearing as large intercellular gaps containing an amorphous material, become evident between satellite cells. During the second half of the incubation period each nerve cell is completely enveloped by a satellite cell sheath, which is in turn entirely surrounded by a connective tissue space. The satellite cells change in shape from star‐shaped to flat elements. By this time and even more so in adult life, satellite cells outnumber nerve cells.The satellite cells increase progressively in number, up to the ninth incubation day mainly through differentiation of undifferentiated cells; but later on by mitotic reproduction of fully differentiated satellite cells.The neuron‐satellite cell boundary becomes more and more complicated with time, thus enlarging in parallel with the increase in volume of the nerve cell. Adhering junctions may be observed along this boundary.The significance of the ergastoplasm, centrioles and cilia of the satellite cells is briefly discussed. Numerous adhering and scarce occluding junctions, some of which are temporary, link satellite cells.
The general visceral efferent component of the eighth cranial nerve
Authors: Ross Muriel D. 
Published: December 2004

AbstractStudy of the brain stem, stato‐acoustic nerve, and inner ear of the mouse by a cholinesterase technique has disclosed that the acetylcholinesterase‐positive centrifugal fibers to the inner ear are part of a general visceral efferent system which supplies fibers to the facial, vestibular and cochlear nerves. This system largely corresponds in its central course to that of the bundle of fibers which has been called “olivocochlear”, but its cells of origin do not appear to lie in the superior olivary complex. Instead, the preganglionic cells of origin are chiefly organized into four nuclei: one medial to the genu of the facial nerve; one lateral to the genu; the superior salivatory nucleus; and a small nucleus lying within the borders of the lateral vestibular nucleus. The fibers to the inner ear synapse, perhaps completely, on postganglionic cells located along their peripheral courses. Additionally, orthosympathetic acetylcholinesterasepositive fibers are present in the cochlear nerve; they arrive via the anterior inferior cerebellar artery. Postganglionic fibers supply not only vascular walls and secretory epithelium in the inner ear but also (1) contact the somata of some acetylcholinesterase‐positive, bipolar cochlear neurons and (2) ramify among, or terminate upon distal, acetylcholinesterase‐positive processes of some sensory neurons at the foramina nervosa. These finding indicate that, on morphological grounds, autonomic nerve activity may influence auditory input at the periphery.
Some aspects of the interneuronal connections in cat's spinal gray matter
Authors: Matsushita Matsuo 
Published: December 2004

AbstractThe pathways of the neurites of various neurons and their interrelations through axon‐collaterals were investigated in the spinal cord of young kittens using silver impregation techniques. The cells of lamina II connect with other cells of laminae II and III through collaterals. The axons of lamina III cells enter the lateral cord and their collaterals connect with cells of laminae III–IV. The axons of lamina V cells enter the lateral cord and some of their collaterals terminate in the neighborhood and in lamina IX. The cells of lamina VI connect with cells of laminae II–VI. The posterior commissural cells give their collaterals to cells of the intermediate nucleus and of the posterior horn of the both sides. Intermediate‐axoned cells (Valverde, '61) were found in the intermediomedial nucleus and lamina VII. Interconnections of small neurons of each lamina (Rexed, '52, '54) and their physiological significance were discussed.
Multiple projection of the visual field to the medial portion of the dorsal lateral geniculate nucleus and the adjacent nuclei of the thalamus of the cat
Authors: Kinston W. J. , Vadas M. A. , Bishop P. O. 
Published: December 2004

AbstractThe organization in the cat of the projection of the visual field onto the medial part of the central half of dorsal lateral geniculate nucleus (LGNd), the medial interlaminar nucleus (MIN) and the posterior nucleus of the thalamus (PN) has been studied by systematically plotting the receptive fields of single units isolated in the nuclei by tungsten microelectrodes. Using a grid of verticals (azimuth) and horizontals (elevation), projection maps were prepared by locating the recording sites of the units in serial histological sections. We have plotted three separate but related topographical projections of the visual field, one in each nucleus. Particular attention was paid to the projection of the visual axis in the LGNd. With the possible exception of the upper periphery, the whole of the visual field is represented in the MIN, the topographical organization with respect to azimuths being the mirror‐image of that in the LGNd. There were very few binocularly activated units in the MIN and no evidence was found of a laminar segregation of crossed and uncrossed optic tract terminals. The topographical projection onto the PN resembled that in the MIN except that the upper visual field was even more restricted and the organization of azimuth values was again reversed such that the central visual field projected inferomedially and the peripheral field dorsolaterally. In all three nuclei a naso‐temporal overlap was found with receptive fields located across the midline in the ipsilateral hemifield for about 2° in the case of LGNd units and 6° or more in the case of the MIN and PN. Some observations are made on visually active units in the lateral posterior nucleus of the thalamus and the pulvinar, many responding binocularly.