bluuebunny/crossref_metadata_2025 huggingface dataset:
Feasibility of Dual-Marking Age-0 Chinook Salmon for Mark–Recapture Studies
Authors: Gaines Phillip C. , Martin Craig D.
Published: December 2004

We investigated the short-term mortality associated with the application of a dual mark on juvenile Chinook salmon Oncorhynchus tshawytscha used in mark–recapture trials. Treatment groups were either spray-dyed with fluorescent pigments, stained with Bismarck brown, or marked with both. Acute mortality was greater for the spray-dyed–Bismarck brown combination (0.48%) and the spray-dyed (0.13%) treatment groups than for the Bismarck brown or control groups. Daily mortality was less than 0.15% for marked treatment groups for 3 d after marking. Cumulative mortality was greatest for the spray-dyed (0.93%) and the spray-dyed– Bismarck brown (0.84%) groups. Significant differences in mortality were not detected among groups (P = 0.063) or within groups on a temporal scale (P = 0.124). Recognition of fluorescent pigments was 100% during the study. Bismarck brown staining did not obscure the fluorescent pigments, which were easily differentiated among colors. We conclude that our dual-marking technique provides researchers with a feasible method to differentially mass-mark fish with minimal mortality. Moreover, mark recognition is greatly enhanced.
Materials for the Next Millenium
Authors: Hondros Ernest D. , Bullock Edward
Published: December 2004

The future of mankind will be influenced by our attitudes towards the overuse of today's materials and to the development and exploitation of new ones. Current supply and demand trends are analyzed and themes of future significance are examined, which include microstructure control and the design of functional materials.
Networks composed of rigid rod polymers
Authors: Ballauff Matthias
Published: December 2004

Rubber elasticity in macromolecules on which the tire industry (for example) relies is the result of the arrangement of the polymer chains as shown in the figure, crosslinked, and connected by flexible hinges. In two recent publications a theory describing this elasticity has been proposed. Mutthius Bullauff reviews this new work and will, in the future, run a regular column in ADVANCED MATERIALS on polymer related topics.

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Advanced materials in the electronics industry
Authors: Meijer Feye
Published: December 2004

Essay: This year sees the 100th anniversary of Philips, one of the world's leading electronics companies. In this special issue an overview of the materials research which forms the basis of the company's development program is provided by researchers from Eindhoven in Holland, and Aachen in Germany. The Essay, from the Director of Research in Einhoven, sets the scene with an account of the general materials requirements in the electronics industry.
Electrocatalytic Hydride‐Forming Compounds for rechargeable batteries
Authors: Notten Peter H. L. , Einerhand Robert E. F.
Published: December 2004

A New class of highly electroactive hydride‐forming compounds is described as well as simple metallurgical methods for producing these materials. The new type of metal alloys consist of two different crystallographic phases. The bulk phase is responsible for hydrogen storage and is formed by the stable multicomponent “standard alloy” of the AB5 type. The second phase homogeneously decorates the surface of the bulk phase and ensures a high electrocatalytic activity. In composing this second phase no precious metals are required, but carefully selected combinations of transition metals can be used. Very high overall exchange currents and discharge efficiencies are obtained, even at low temperature. Cycle life and storage capacities are comparable with the values found for the standard alloy. Substituting small amounts of B‐metals with highly electrocatalytic elements was also found to be effective in improving the electroactivity of AB5 compounds. However, a drawback of this method is that significant improvements are obtained only when precious metals are incorporated. Double‐phase materials must therefore be considered as more serious candidates for use in future nickel/metal‐hydride batteries with high charge/discharge capability.
Nanocrystalline Materials for video recorder heads
Authors: De Wit Hendrik Jan , Witmer Cor H. M. , Dirne Frank W. A.
Published: December 2004

In present video recorders the magnetic materials of the record/playback head is usually a crystalline ferrite. These materials are, however, not so suitable, when substantially finer details on the magnetic tape are required, e.g. for high‐definition television (HDTV) recording. The search for an alternative has resulted in a new type of magnetic material: multilayers in which crystalline iron layers of about 10 nm thickness are alternated with even thinner amorphous iron‐alloy layers. These ‘nanocrystalline’ materials combine a high saturation magnetization with a high permeability in the MHz frequency range, allowing video recording at much increased information densities.
High‐resolution Electron Microscopy of semiconductors and metals
Authors: Bulle‐Lieuwma Corrie W. T. , Coene Wim , Frank de Jong A.
Published: December 2004

Review: Two‐dimensional information on the microstructure of materials at a resolution comparable to interatomic distances is crucial for the study of interfaces, defects, growth mechanisms etc. One of the most important analytical methods for gaining such information is high‐resolution electron microscopy (HREM). The interpretation of the results on semiconductors, magnetic alloys and multilayers, can often be facilitated through image processing and simulation.
Anisotropic networks formed by photopolymerization of liquid‐crystalline molecules
Authors: Hikmet Rifat A. M. , Lub Johan , Broer Dirk J.
Published: December 2004

Research News: Oriented polymeric structures can possess anisotropic optical, electrical, and thermo‐mechanical properties which make them of interest for application in the production of polarizers, waveguides, optical filters, and wave plates. One method of producing such structures, the photopolymerization of self organizing liquid‐crystalline molecules is discussed and the applications of structures derived from nematics, cholesterics, and anisotropic gels described.
Butyltin speciation in sediments and biological samples by hydride generation gas chromatography quartz furnace atomic absorption spectrometry; a study of acid leaching procedures and hydride generation
Authors: Desauziers V , Leguille F , Lavigne R , Astruc M , Pinel R
Published: December 2004

The efficiency of the extraction of butyltin compounds from sediments and biological matter by acid leaching procedures has been evaluated on real samples using the hydride generation gas chromatography quartz furnace atomic absorption (GC AA) speciation method. The most efficient method uses cold pure acetic acid over a period of four hours. Hydride generation using sodium tetrahydroborate (NaBH4) is dependent on matrix composition and care must be taken to adapt the amount of reactant to the organic content of the sample.
Adsorption and desorption of tributyltin in sediments of San Diego Bay and Pearl Harbor
Authors: Kram Mark L , Stang Peter M , Seligman Peter F
Published: December 2004

Adsorption and desorption of butyltin compounds from sediment under simulated estuarine conditions depends upon the characteristics of the sediment including grain size distribution, percentage of organic carbon, clay mineralogy and aqueous butyltin concentration in the overlying water column. Sediments from Pearl Harbor, Hawaii, USA, primarily consisting of calcium carbonate mud and 18–28% organic carbon by weight, have generally abundant adsorption sites and display tributyltin partition coefficients (Kp) ranging from 1000 to 5000 μg kg−1 per μdm−3. Adsorption and desorption of butyltin from San Diego Bay, California, USA, sediments is linearly dependent upon the characteristics of each sediment and the range in Kp values is from approximately 20 to 2500 μg kg−1 per μg dm−3. Sandy, low‐organic carbon sediments have low Kp while fine‐grained, relatively organic‐rich sediments have high Kp values. Similarly, samples containing significant amounts of high cation exchange capacity (CEC) clay minerals have relatively higher adsorption potentials than those consisting of low CEC minerals.
Organotin compounds as energy‐potentiated uncouplers of rat liver mitochondria
Authors: Connerton Ian F , Griffiths David E
Published: December 2004

Triorganotins will titrate membrane potential (Δψ) and the accompanying pH gradient (ΔpH) in estimates of protonmotive force (Δp) in isolated rat liver mitochondria in an apparent concentrationdependent manner and in minimal halide media (5 μmol dm−3). Under these conditions the concentrations of organotin required to produce a drop of 80–120mV in Δp approach or are in excess of those required to inhibit ATP‐synthase activity, which are at least three‐fold greater than those which inhibit ATP hydrolytic activity. The addition of exogenous chloride ion did not appreciably alter the steady‐state or rate estimates of triorganotin‐mediated membrane potential (Δψ) depolarization. The evidence indicates that triorganotins possess an uncoupling effect which is independent of halide/hydroxyl exchange or direct inhibition of the ATPase complex. The activity of various triorganotins may be best understood according to their abilities to uncouple or directly inhibit oxidative phosphorylation at the enzymic level, in the absence of halide/hydroxyl exchange.
Preparation of rhodium–phyllosilicate catalysts without leaching in liquid‐phase 1‐hexene hydrogenation
Authors: Herrero Juana , Blanco Carmen , Oro Luis A
Published: December 2004

Rhodium catalysts have been prepared on palygorskite and montmorillonite (clay) supports by reduction with hydrogen (1 atmosphere) at room temperature of a cationic organometallic rhodium compound anchored to the support. The activity of these catalysts for the hydrogenation of liquid‐phase 1‐hexene remains constant with increase of prehydrogenation time and with re‐use for several runs. No rhodium leaching is observed.
Syngas reactions XII. The selective preparation of acetaldehyde, alkanols, esters and acetic acid from synthesis gas
Authors: Knifton John F , Lin J J
Published: December 2004

Several classes of commercially important oxygenates, including acetaldehyde, ethanol, methyl acetate, ethyl acetate and acetic acid as well as C1–C3alcohol/acetate ester mixtures, may each be selectivelygenerated from synthesis gas through the application of novel classes of ruthenium‐containing bimetallic catalysts particularly those of ruthenium and cobalt (RuCo). A particular feature of these versatile catalysts is that all precursors are iodidefree. Products are formed through a combination of carbon monoxide hydrogenation, methanol homologation, methyl acetate homologation and methanol carbonylation reaction sequences.
Evaluation of the activity of some water‐soluble ferrocene and ferricenium compounds against carcinoma of the lung by the human tumor clonogenic assay
Authors: Neuse Eberhard W , Kanzawa Fumihiko
Published: December 2004

The two ferrocene compounds, ferrocenylacetic acid (3) and ferrocylthiomalic acid (4), as well as the ferricenium salts, ferricenium tetrachloroferrate (III) (1) and ferricenium trichloroacetate–trichloroacetic acid solvate (2), were investigated by the in vitro human tumor clonogenic assay for their inhibiting effects, in continuous exposure in a double‐layer medium, on the colony formation of single‐cell suspensions prepared from 30 selected fresh specimens of human adenocarcinoma, squamous cell carcinoma and large‐cell carcinoma of the lung. At the high drug concentration level of 100 μg cm −3, good response ratios were observed for 3 (79%) and 4 (72%), followed by 1 (67%) and 2 (52%). At the low concentration level of 10 μg cm−3 response ratios were below 25% for all compounds, best performance (24%) being shown by 1. In vitro experiments probing the schedule dependencies of the compounds' inhibiting effects against the lung carcinoma cell line PC‐9 were also performed, as were experiments involving the combination of the ferricenium salt 1 and cisplatin, which showed the combination effect to be additive in both one‐hour and continuous‐exposure tests.
Bis(tributyltin) oxide as a wood preservative: Its conversion to tributyltin carboxylates in Pinus sylvestris
Authors: Blunden S J , Hill R.
Published: December 2004

Tributyltin compounds have been successfully used for many years as wood preservatives, although their chemical nature in timber has not been fully elucidated. This study by 119Sn and 13C NMR spectroscopy has shown that, on impregnation into Pinus sylvestris sapwood, bis(tributyltin) oxide [(Bu3Sn)2O] is rapidly converted to tributyltin carboxylates (Bu3SnOCO·R) via reaction with components of the wood resin. It is further suggested that the formation of these species is a prerequisite for the known disproportionation reaction which occurs in (Bu3Sn)2O‐treated timber.
Electrochemical behaviour of some organotin(IV) compounds by rotating disc voltammetry in non‐aqueous solvents
Authors: Abeed Fathi A , Al‐Allaf Talal A K , Sh Ahmed Kareem
Published: December 2004

The electrochemical behaviour of three series of organotin(IV) compounds having the general formula RySnX4−y (R = Me, nBu or Ph, y = 2 or 3, X = Cl; R = Me or Ph, y = 3, X = NO3, N3, NCS, NCO, OAc or OH) have been examined in the non‐aqueous solvents dimethylformamide and acetonitrile, at rotating disc electrodes of glassy carbon and gold electrodes. The reduction of tin(IV) in the above series gave a single wave and obeyed the Levich plots at both electrodes in the two solvents. The electrode kinetic parameters and halfwave potentials have been determined, and the effect of solvents and substituents on these parameters have been explored.
Surface‐bound organometallic rhodium precursors for 1‐hexene hydrogenation
Authors: Herrero Juana , Blanco Carmen , Esteruelas Miguel A. , Oro Luis A.
Published: December 2004

Rhodium precursor catalysts supported on palygorskite, montmorillonite and silica were obtained from an organometallic cationic rhodium species and evacuated supports at different temperatures. Based on the different times which precursors took to be active in 1‐hexene hydrogenation, in the liquid phase at atmospheric hydrogen pressure, it has been deduced that the supported rhodium species varies with the support and its dehydration temperature. Activity in this reaction also depended on the support, its dehydration temperature and storage in air. Precursors and catalysts were characterized by X‐ray photoelectron and infrared spectroscopy. Very stable complexes are obtained under humid ambient conditions. With montmorillonite support, activity decreases if rhodium/1‐hexene ratio decreases.
Effect of selenium on arsenic metabolism in Cylindrotheca fusiformis
Authors: Katayama Masayuki , Sugawa‐Katayama Yohko , Benson Andrew A.
Published: December 2004

Effects of selenium (Se) on the kinetics of incorporation and excretion of 74As have been studied by use of a marine diatom, Cylindrotheca fusiformis. For the incorporation experiment, the cells were incubated with carrier‐free 74As in a phosphate‐free normal medium, and collected sequentially over 45 h. For the excretion experiment, the cells were transferred to a normal medium and collected sequentially over 95 h. The cell components were fractionated into watersoluble, insoluble and lipid fractions by TLC. 74As was mostly incorporated into the water‐soluble fraction and less than 10% of it into the insoluble and lipid fractions. Within a few hours considerable amounts of 74As were found in those fractios, but after that the rate of accumulation decreased. 74As was excreted into the medium rapidly at the beginning, but the rate of excretion slowed down gradually. In the cells, the amount of As in the insoluble fraction decreased more rapidly than that in the lipid and water‐soluble fractions. The time course changes of 74As in the three fractions showed some oscillation of larger amplitude of variation at first and later approached a constant value. Selenium in the medium showed some effects o the rate of arsenic incorporation as well as on the ratio of the three fractions. In the excretion process, selenium changed the amplitude of the variation and the ratio of 74As in the three fractions at the later times.
Crown ethers in tin chemistry
Authors: Cusack Paul A , Smith Peter J
Published: December 2004

This article comprehensively reviews the literature concerning the adducts formed between crown ethers and organotin(IV), inorganic tin(IV) and inorganic tin(II) species, and it also covers organotin(II) complexes containing alkali metal–crown ether cations. The uses of crown ethers as cocatalysts in organic and organotin synthesis are surveyed and some potential industrial applications of crown ether/tin chemical systems are discussed.
The synergistic effect of polysorbate 80 upon the toxicity of tri‐n‐butyltin chloride
Authors: Sherman Larry R , Kellner Ginny L
Published: December 2004

Polysorbate 80 (Tween 80) was used as an emulsifying agent for administering tri‐n‐butyltin chloride (TBTCl) to rats below, at and above the LD50 for the compound. Tween 80 greatly enhanced the toxicity of the organotin compound. The LD50 in the presence of Tween 80 (16% of the emulsion) is less than half of the LD50 when the TBTCl was administered in corn oil.
Structural chemistry of organotin carboxylates: a review of the crystallographic literature
Authors: Tiekink Edward R T
Published: December 2004

This review describes the structural chemistry of organotin carboxylates, covering data acquired for mono‐, di‐ and tri‐organotin compounds and complexes. A brief discussion is given for organotin amino‐acid derivatives.
Synthesis, characterization and catalytic activity of Rh (PPh3)2 (en)Cl complex
Authors: Gokak D T , Kamath B V , Ram R N
Published: December 2004

Ethylenediamine bis(triphenylphosphine) monochlororhodium has been prepared by the interaction of Wilkinson's catalyst and ethylenediamine in benzene. The complex has been isolated and characterized by conventional and spectroscopic methods. The catalytic activity of the complex was investigated for the hydrogenation of 1‐octene as a model reaction at a hydrogen pressure of 1 atmosphere (101 kPa) using methanol as a solvent. The influence of various factors such as catalyst, substrate concentrations and temperature have been studied. The hydrido complex has been identified as an intermediate product by IR and NMR studies. The experimental data are in accordance with a rate expression of the form:

.
Antifungicidal, antibacterial and antifertility activities of biologically active heterocyclic thiosemicarbazones and their coordination complexes with the dimethylsilicon moiety
Authors: Singh D , Singh R V , Goyal R B
Published: December 2004

Synthetic, structural and biological aspects of trigonal‐bipyramidal, Me2Si(NS)Cl and octahedral, Me2Si(NS)2 types of organosilicon (IV) complexes of heterocyclic thiosemicarbazones (NSH) have been described. The complexes were characterized by elemental analysis, molecular weight determination, conductance measurements and electronic, infrared, 1H and 13C NMR spectral studies. Some ligands and their corresponding dimethylsilicon (IV) complexes have been tested for their effects on several pathogenic fungi and bacteria. Two representative complexes have also been found to act as sterilizing agents by reducing the production of sperm in male mice.
Sedimentary siloxanes: A depositional history
Authors: Pellenbarg Robert E , Carhart Homer W
Published: December 2004

A Puget Sound sediment core has been quantitatively analyzed for organic silicon content, as derived from post‐1945 release of poly(organo)‐siloxanes (silicones). The sedimentary silicone data record and preserve at depth, a smeared event horizon, or first appearance of silicone in the sediment column. Core samples older than 50 years showed no detectable silicone as measured by a new procedure utilizing inductively coupled plasma (ICP) emission spectroscopy after solvent extraction to collect the silicone from gram‐sized sediment core samples.
Research on tributyltin in Australian estuaries
Authors: Batley Graeme E , Scammell Marcus S
Published: December 2004

Tributyltin (TBT) from marine antifouling paints has been shown to have a major impact on the oyster industry in eastern Australia. Current research projects are examining the impact of TBT on Australian estuaries, assessing the response of sensitive biota to recently imposed bans and determining whether a continuing use of TBT on large vessels is an environmental concern.
Speciation for analysis of organotin compounds by GC AA and GC MS after ethylation by sodium tetraethylborate
Authors: Ashby J R , Craig P J
Published: December 2004

A range of organotin compounds has been ethylated using the reagent sodium tetraethylborate in a simple one‐step procedure. Analysis of the volatile, fully alkylated derivatives has been achieved by GC AA with confirmation of the identity of the resulting ethylated derivatives by GC MS. Conditions for the GC AA and GC MS analysis of the organometallic ethyl derivatives are given.
Active sites, nature and mechanism of carbon dioxide—propylene oxide copolymerization and cyclization reactions employing organozinc—oxygen catalysts
Authors: Kuran Witold
Published: December 2004

Reaction of carbon dioxide with propylene oxide in the presence of catalysts with condensed zinc species (;derived from diethylzinc and dihydric phenols, e.g. catechol o C6H4(;OH)2 and saligenin 0 HOC6H4CH2OH) yields poly(;propylene carbonate) as well as propylene carbonate. The above reaction in the presence of catalysts with noncondensed zinc species (;derived from diethylzinc and phenol) yields propylene carbonate as the main product, but in relatively low yield. The mechanism of the linear and cyclic carbonate formation is discussed in terms of the nature of the catalyst's active sites for both types.
Synthesis, characterization and in vitro antitumour activity of di‐n‐butyltin(;iv) derivatives of some aromatic carboxylic acids, including aspirin
Authors: Meriem Abdelkader , Willem Rudolph , Biesemans Monique , Mahieu Bernard , de Vos Dick , Lelieveld Peter , Gielen Marcel
Published: December 2004

Eleven di‐n‐butyltin(;IV) derivatives of the type (;a) (;C4H9)2(;XYC6H3COO)2Sn or (;b) {[(;C4H9)2(;XYC6‐H3COO)Sn]2O}2 (;X, Y = H, 2‐OH, compound 1a; H, 2‐OCH3, compounds 2a and 2b; H, 2‐OCOCH3, 3a; 2‐OH, 3‐OCH3, 4a; 2‐OH, 3‐CH3, 5a; H, 3‐OCH3, 6a and 6b; H, 3‐N(;CH3)2, 7a; H, 2‐(;CF3), 5‐(;CF3), 8a and 3‐OCH3, 4‐OH, 9a) have been prepared and characterized by 1H, 13C and 119Sn NMR, Mössbauer and mass spectroscopy. The in vitro antitumour activity of these compounds against MCF‐7 human tumour cells was higher than that of cis‐platin, but only three compounds, 4a, 8a and 9a, scored better than cis‐platin against the WiDr cell line.
Syntheses and electrochemical behaviour of novel dmit or dmio (dithiolato) cobalt(iii) complexes with a η5‐cyclopentadienyl or η5‐pentamethylcyclopentadienyl ring
Authors: Ushijima Hirobumi , Sudoh Susumu , Kajitani Masatsugu , Shimizu Kunio , Akiyama Takeo , Sugimori Akira
Published: December 2004

Four novel cobalt(III) complexes with a cyclopentadienyl or pentamethylcyclopentadienyl ring and dmit or dmio ligands were synthesized, and their electrochemical behaviour was investigated. All these complexes exhibited three one‐electron transfer steps: one reduction and two oxidation steps. In addition, a novel organosulphur compound was afforded by electrochemical oxidation of dmit cobalt complex. Thus, these complexes may have considerable synthetic potential as precursors for electron reservoirs and organosulphur compounds.
Dissociative photoionization of Al2(Ch3)6 and Al2(Ch3)3Cl3 in the range 40–100 eV
Authors: Nagaoka Shin‐Ichi , Koyano Inosuke , Imamura Takashi , Masuoka Toshio
Published: December 2004

Dissociation processes of the organoaluminum compounds Al2(CH3)6 and Al2(CH3)3Cl3 have been studied in the range of valence and Al:2p core‐level ionization by means of photoelectron–photoion and photoion–photoion coincidence techniques. The double‐ionization threshold and the Al:2p core‐ionization threshold of Al2(CH3)6 are estimated to be about 30 and 80 eV

1 eV = 96.4853 kJ mol−1.

respectively. The relative yields of the H+Al+ and H+CHm,+ (m′ = 0–3) ion pairs are enhanced around the Al:2p core‐ionization threshold of Al2(CH3)6. The photoion–photoion coincidence intensities of Al2(CH3)3Cl3 are negligibly small throughout the energy range studied. The ratio of the relative yield of AlC2H6+ to that of Al+ increases smoothly through the Al:2p core‐ionization and/or excitation region of Al2(CH3)3Cl3. The variation of the fragmentation pattern with photon energy is discussed in conjunction with the relevant electronic states.
Hydrogermylation of phenylacetylene catalyzed by onium chlorometallates
Authors: Lukevics E , Barabanov D I , Ignatovich L M
Published: December 2004

Triethylbenzylammonium chlorometallates [Et3NCH2Ph][MCln]m− (M = Pt, Pd, Rh, Ir, Fe, Co, Cu, m = 1–3, n = 3–6), polymer‐anchored ionic metal complexes [℗—CH2PBu3][MCln]n− and some other chlorometallates and complexes of platinum, rhodium, ruthenium and osmium were studied as catalysts in the hydrogermylation of phenylacetylene with triethylgermane. All the complexes containing platinum, palladium and rhodium were found to be effective catalysts. The cis/trans ratio of the products obtained is determined by the metal atom involved and decreases in the following order: Ir > Rh ≫ Pd > Pt.
Conversion of arsenobetaine by intestinal bacteria of a mollusc Liolophura japonica chitons
Authors: Hanaoka Ken'Ichi , Motoya Tomoko , Tagawa Shoji , Kaise Toshikazu
Published: December 2004

The intestinal micro‐organisms of Liolophura japonica chitons converted arsenobetaine [(CH3)3As+CH2COO−] to trimethylarsine oxide [(CH3)3AsO] and dimethylarsinic acid [(CH3)2AsOOH] in the arsenobetaine‐containing 1/5 ZoBell 2216E medium under aerobic conditions, no conversion being observed in an inorganic salt medium. This conversion pattern of arsenobetaine → trimethylarsine oxide ← dimethylarsinic acid was comparable with that shown by the microorganisms associated with marine macroalgae. On the other hand, no conversion was observed in either medium under anaerobic conditions.
Facile esterification promoted by the triphenylstibine oxide‐phosphorus sulfide (Ph3SbO/P4S10) system
Authors: Nomura Ryôcki , Miyazaki Shin‐Ichiro , Nakano Takahiro , Matsuda Haruo
Published: December 2004

Various esters are conveniently prepared by direct esterification of the corresponding carboxylic acids with alcohols catalyzed by a triphenylstibine oxide–phosphorus(V) sulfide combined system (Ph3SbO/P4S10) under mild conditions (25–80 °C).
Speciation of butyltin compounds by on‐line HPLC‐ETAA of tropolone complexes in environmental samples
Authors: Astruc A , Astruc M , Pinel R , Potin‐Gautier M
Published: December 2004

Tropolone (Trop) forms in solution stable complexes with monobutyltin (MBT Trop2) and dibutyltin (DBT Trop). This property has been used to develop a separation procedure of butyltin compounds by liquid chromatography on cyanopropyl‐bonded silica columns with a solution of tropolone in toluene as eluent.

Tin‐specific detection by on‐line ETAA allowed the development of a simple procedure suitable for the determination of tributyltin and dibutyltin in water and sediment samples.
Synthesis and spectroscopic characterization of dimethyl‐, di‐n‐butyl‐, di‐t‐butyl‐and diphenyl‐tin(iv) derivatives of dipeptides: Crystal and molecular structure of di‐n‐butyltin(iv) glycylvalinate
Authors: Mundus‐Glowacki Brigitte , Huber Friedo , Preut Hans , Ruisi Giuseppe , Barbieri Renato
Published: December 2004

The dipeptide complexes R2SnL listed below have been synthesized: (a) Me2SnL; H2L = glycylalanine (H2GlyAla), glycylvaline (H2GlyVal), glycylmethionine (H2GlyMet), glycyltryptophan (H2GlyTrp), glycyltyrosine (H2GlyTyr); (b) nBu2SnL; H2L = H2GlyAla, H2GlyVal; (c) nBu2SnL.H2O; H2L = glycylglycine (H2GlyGly), H2GlyAla; (d) tBu2SnL; H2L = H2GlyAla, H2GlyVal; (e) tBu2SnGlyGly. H2O; (f) Ph2SnL; H2L = H2GlyAla, H2GlyVal, H2GlyTyr, H2GlyTrp; (g) Ph2Sn(HGlyVal)2. The crystal and molecular structures of nBu2SnGl Val have been determined by single‐crystal X‐ray diffraction. The polyhedron around tin is a distorted trigonal bipyramid, analogous to that of Et2SnGlyTyr (see Vornefeld et al., Appl. Organomet. Chem., 1992, 6: 75). According to infrared and 119Sn (ΔE parameters) Mössbauer spectroscopic data the R2SnL derivatives can be classified by their solid‐state structure into two types which are distinguished by the nature of the axial carboxylate [(i) monodentate, as in nBu2SnGlyVal; (ii) bidentate]. Bonding in R2SnL.H2O and Ph2Sn(HGlyVal)2 has been discussed on the basis of vibrational data. Rationalization of the 119Sn Mössbauer parameters has been attempted by ‘literal’ point‐charge model, calculations of ΔE in the structural context described above. According to 13C NMR spectra, compounds Me2SnL are undissociated in methanol solutions, whilst dissociation is inferred for aqueous solutions, probably concerning the carboxyl and amino groups only. Five‐coordination in methanol and aqueous solutions has been assumed for Me2Snl from 119Sn NMR chemical shifts. Values of coupling constants |2J(119Sn, 1H)|, determined from 1H NMR spectra, gave estimates of CSnC angles in Me2SnL in the range 128–136° in methanol and aqueous solutions, which correspond to values from 119Sn Mössbauer ΔE parameters (129.6–133.8°). The structural relationship of R2SnL molecules in the solid state and in solution phase has been discussed.
Confusion between dimethyl selenenyl sulfide and dimethyl selenone released by bacteria
Authors: Chasteen Thomas G
Published: December 2004

Dimethyl selenone [(CH3)2SeO2] has been reported in the literature as a metabolite released by bacteria in contact with selenium metal or selenium salts. In this study, mass spectral, chromatographic, and boiling‐point data are presented that show that dimethyl selenone has been confused with dimethyl selenenyl sulfide (CH3SeSCH3). In addition, the headspaces above monocultures of selenium‐resistant bacteria were examined using gas chromatography followed by fluorine‐induced chemiluminescence detection. A number of alkyl sulfur and selenium species were detected, along with dimethyl selenenyl sulfide. A pathway from oxidized selenium salts to reduced methylated selenides and dimethyl selenenyl sulfide is also presented.
Kinetics of substitution at ternary titanium(IV)–cyclopentadienyl, pyronato or pyridinato–halide or alkoxide complexes
Authors: Burgess John , Parsons Simon A
Published: December 2004

Rate laws and kinetic parameters are reported for substitution at titanium(IV) complexes Ti(LL)2X2, where LLH=cyclopentadiene, the 4‐pyrone ethylmaltol, several 4‐pyridinones, and related ligands, and X=halide or alkoxide, in acetonitrile solution at 298.2 K. Reactivities are discussed in terms of the nature of the leaving group, the entering group and the non‐leaving ligand LL−. Activation volumes of −15 and −12 cm3 mol−1 have been determined for thiocyanate attack at Ti(cp)2Cl2 and Ti(etmalt)2Cl2 respectively. Substitution mechanisms are discussed in the light of the kinetic parameters obtained.
Linus Carl Pauling ‐ 28. 2. 1901 ‐ 17.8. 1994
Authors: Jaenicke Lothar
Published: December 2004

Das Jahr 1939 steht, wie in der Geschichte der Menschheit, auch in der der Chemie wie eine Zeitenwende: Während von Berlin aus in der Welt die Lichter ausgelöscht wurden, erschien in New York ein Buch von mäßigem Umfang: Linus Pauling: „The Nature of the Chemical Bond and the Structure of Molecules and Crystals ‐ An Introduction to Modern Structural Chemistry”︁. Man kann seit diesem fokussierenden Genieblitz tatsächlich die Chemie in ihren weitesten Ausstrahlungen als Zeit vor (B. P.) und nach Pauling (A. P.) zählen, denn dieses Buch hatte einen ungeheuren Einfluß auf alles, das chemisch ist ‐ und das ist alles Tote und Lebende, weil es durch chemische Bindungen in Form und im Raum gehalten wird. Und es ist nicht ein Zufallsstreich, sondern das Ergebnis einer phänomenalen Zusammenschau und einer, durch Gespür für das, was die Natur zusammenhält, zielvoll gelenkten, von Intuition beflügelten und seismorgraphisch alle Anregungen aufnehmenden, ungeheuer optimistischen geistigen und experimentellen Arbeit eines Mannes, der zugleich die Phantasie hatte, die neuen Vorstellungen auf viele in den Kulissen stehende Fragen anzuwenden, so daß wir heute reflexmäßig die Vorgänge in uns und um uns herum als Yin/Yang(Paß)‐Kommunikation zwischen Atomen, Molekülen und höher strukturierten Verbänden, Organisationen interpretieren.
The pigeon retina: Quantitative aspects of the optic nerve and ganglion cell layer
Authors: Binggeli Richard L. , Paule W. J.
Published: December 2004

Studies of electron micrographs of pigeon optic nerve showed numerous unmyelinated fibers (29% of total) and more than twice as many total fibers as previously reported. The 2.4 million axons had a mean diameter below 1 μ, close to the limit of resolution of light microscopy. This probably accounts for the large discrepancy between light and electron microscopic counts. Studies of retinal whole mounts showed an irregular distribution of cells in the ganglion cell layer including a minor posterior fovea and an area of increased density in the posterior‐superior quadrant. Sample counts produced an estimate of over 4.8 million cell bodies in this layer. Cytological investigation indicated that over 85% of these cells were neuronal. The considerable excess of neuron cell bodies over axons in thought to be explained by the presence of large numbers of amacrine cells, cells which do not project axons into the optic nerve.
Localization of primary sensory afferents in the prothoracic ganglion of the wood ant (Formica lugubris Zett.): A combined light and electron microscopic study of secondary degeneration
Authors: Lamparter Hans‐Eckart , Akert Konard , Sandri Clara
Published: December 2004

Secondary degeneration of foreleg afferents was traced in the prothoracic ganglion of the common wood ant (Formica lugubris Zett) with the aid of phase contrast and electron microscopy. The legs were amputated at the coxal level in 43 workers; 1–35 days were allowed for degeneration. Localization of degenerated sensory nerves in the entering nerve root and within the neuropil of the ganglion was opumal after 4‐10 days. Afferent fibers were found predominantly in the ipsilateral half of the ganglion. However, a few fibers seemed to cross the midline and to end in the medial portion of the contralateral side. No degenerations could be located within the cranial and caudal connectives. The significance of the findings with respect to the problem of functional localization pattern in the neuropil of an insect ganglion is discussed.
Quantitative teased‐fiber and histologic studies of human sural nerve during postnatal development
Authors: Gutrecht Jose A. , Dyck Peter J.
Published: December 2004

Quantitative histologic and teased‐fiber measurements were made on specimens of sural nerves of man in the first two decades of life, thus providing normal data not previously availabel. As previously reported for nerves from adults, there was a linear relationship between diameter and length of internodes: large fibers had long internodes and small fibers had short internodes. The slopes of the regression lines calculated for this relationship for each of these nerves became steeper with increasing age. In the second decade the slope became similar to that of nerves of adults.

The transverse fascicular area increased particularly during the first five years of life. The number of myelinated fibers per nerve varied from approximately 4,000 to 12,300, the lowest value occurring in the nerve of the newborn. The frequency distribution of the myelinated fibers was unimodal in the newborn and was already bimodal by the seventh month. Whereas the peak of the small fiber group remained in the 2.0 to 2.9–μ size group in all nerves, the peak of the large fiber group shifted to larger size categories with increasing age, reaching adults values just after the age of five years. This correlates well with the age at which maximal conduction velocities are attained in the ulnar nerve.

The diameter of the axis cylinder bore a linear relationship to the diameter of the whole myelinated fiber: small fibers had thin myelin sheaths and large fibers had thick ones. The value of the ratio of the diameters incresed progressively from small to large fibers, a result which is probably spurious. The slope of the regression lines for the relationship of diameter of axis cylinder to diameter of the whole fiber was the same for nerves of persons of different ages.
Exceptions to bilateral symmetry in the epithalamus of lower vertebrates
Authors: Braitenberg Valentino , Kemali Milena
Published: December 2004

Fifty series of sections through the frog's brain, four series of the newt's brain and two series of the eel's brain were searched for asymmetries in the epithalamic region. Marked differences between the right and left habenular nuclei were found in all cases, in the sense that the left one had a more lobate structure than its right counterpart.
Anatomical connections of visual system with limbic cortex of monkey
Authors: MacLean Paul D. , Creswell George
Published: December 2004

The question of anatomical connections between the visual system and the temporo‐occipital limbic cortex was investigated in 24 squirrel monkeys (Saimiri sciureus) with the utilization of stains for showing fine degenerating cortical fibers. Lesions of various size were placed in the geniculo‐pulvinar complex by electrocoagulation. Electrodes were usually inserted in the Horsley‐Clarke frontal plane, but in two cases lesions of the lateral geniculate body were made by an extracerebral approach.

With a lesion well confined to the ventrolateral part of the lateral geniculate body, heavy degeneration appeared in the inferior longitudinal fasciculus and continued into its ventromedial extension designated as band 3 in the core of the posterior hippocampal gyrus. Some degenerating fibers could be traced from band 3 into the cortex of this gyrus, as well as into adjoining cortical areas in the fusiform and lingual gyri. Sparse degeneration in the postsplenial cortex could not be excluded as arising from the lesion made by an electrode in approaching the lateral geniculate body in the frontal plane. Degeneration in band 3 did not extend as far forward as the entorhinal cortex in the anterior hippocampal gyrus. In two animals with small rostral lesions of the lateral geniculate body made by the extracerebral approach, some degeneration also extended into band 3, supporting other control observations that such degeneration is not dependent on the destruction of tissue made by an electrode in approaching the lateral geniculate body in the frontal plane.

When a lesion involved the inferior pulvinar as well as the lateral geniculate body, heavier degeneration appeared in the posterior hippocampal, fusiform, and lingual cortex. With a large lesion of the inferior pulvinar, a band of degeneration appeared ventrolateral to the optic radiations and was traced into these same cortical areas.

The anatomical results are discussed in the light of recent microelectrode findings of photically responsive units in the cortex of posterior hippocampal gyrus and adjoining cortical areas. The combined evidence suggests an explanation for the temporal detour made by that part of the optic radiations commonly referred to as Meyer's temporal loop.
Nigrofugal connections in the primate brain
Authors: Mettler Fred A.
Published: December 2004

The great mass of large cells which make up the compact part of the substantia nigra send their stout primary axons to the ipsilateral globus pallidus. A much smaller‐ipsilateral striatal projection can also be easily substantiated. This comes chiefly from cells in the reticulata but not exclusively so. In general, the lateral reticulata projects to the putamen and the medial to the caudate. If the synapses in the ventrolateral part of the thalamus, which have been described to degenerate to degenerate after lesions in the nigra, are established by nigrofugal, rather than by other fiber systems, they would seem to be the endings of collaterals given off en route to the lentiform nucleus, rather than primary projection elements. If any fibers from the nigra cross the midline, or descend, they must be very few.
Formation and migration of neuroblasts in the spinal cord of the chick embryo
Authors: Langman Jan , Haden Cheryl C.
Published: December 2004

To determine the origin, migration pattern and final localization of the neurons in the spinal cord, chick embryos ranging in age from two to eight days were treated with two doses of tritiated thymidine with an interval of two to four hours and sacrificed at various days thereafter. As a result of this labeling procedure, all neuroepithelial cells were labeled; hence all neuroblasts arising from the neuroepithelial cells after the treatment were labeled, while those formed earlier were unlabeled. By examining the position of the unlabeled neuroblasts at daily intervals, the migration route and final localization of these neurons could be determined.

Neuroblasts formed on days two and three are initially found along the inside of the basement membrane in the ventrolateral as well as the dorsolateral region of the cord. During the following days, however, the neuroblasts found in the dorsolateral region disappear and by day 8 the majority of the two‐and three‐day neuroblasts is concentrated in the lateral region of the anterior horn. Since no evidence for degeneration of neuroblasts was found in the alar plate region, it is probable that „alar plate neuroblasts”︁ migrate to the region of the anterior horn.

The majority of the neuroblasts formed on days 3 and 4 finds its final position in the lateral region of the anterior horn; the majority of those formed on days 5 and 6, however, occupies a position in the medial region of the anterior horn. Hence, the majority of the motor neurons innervating the muscles of the extremities is formed earlier than those innervating the trunk musculature.

The neuroblasts of the internuncial zone are formed on days 2 through 7, that is, during the entire period that neuroblast formation in the spinal cord occurs. The majority of the neuroblasts for the posterior horn arises on days 6 and 7, while the last ones are formed on day 8. Despite the fact that the majority of the neuroblasts for the anterior horn is formed before those of the internuncial zone and these in turn before those of the posterior horn, none of the cell groups in either region is formed within a sharply delineated time period.
Observations on initial segments of axons in the prepyriform cortex of the rat
Authors: Westrum Lesnick E.
Published: December 2004

Layers II and III of the prepyriform cortex of rats were studied with the electron microscope and with a rapid Golgi method. Initial segments of axons were identified according to the criteria previously established. The fixative optimum for demonstrating microtubules and differentiating initial segments from dendrites must include glutaraldehyde. Initial segments were found to possess lateral projections, herein referred to as axonic spines and their fine structural features and synaptology are described. The synapses on initial segments and axonic spines predominately contain flattened vesicles and a spine apparatus‐like organelle is often present. The problem of the origin of these synapses is discussed.
The effect of unilateral deprivation on visual centers in rats
Authors: Fifková E.
Published: December 2004

The effect of unilateral visual deprivation by lid suture on visual centers was studied in rats. In animals with previous visual experience this caused a decrease in volume of the dorsal nucleus of the lateral geniculate body and nucleus lateralis pars posterior of 10% and 8% respectively, a decrease in the thickness of layers II to IV of the visual cortex of 8% and an increase in cell density in cortical layers III and IV of 12% and 10% respectively. These changes were of the same magnitude as in rats which had no previous visual experience. Quantitative changes in deprived visual centers were detectable ten days after lid suture; the process reached its maximum after 30 days. The number of spines on the apical dendrites of pyramidal cells of layer V, observed in layer IV, was reduced by 17% after ten days of visual deprivation and by 28% after 30 days. Reopening of the eye for 10 and 30 days following two months of lid closure caused no recovery in the deprived visual centers.
Effects of hyothalamic lesions at different loci on development of hyperinsulinemia and obesity in the weanling rat
Authors: Bernardis Lee L. , Frohman Lawrence A.
Published: December 2004

Bilateral electrolytic lesions were produced in eight different hypothalamic areas in weanling female rats to localize the area associated with hypothalamic obesity. Animals were maintained for five weeks and food intake measured. After sacrifice, changes in carcass fat content, plasma insulin and plasma glucose were compared to value obtained from sham‐operated controls. Only rats with lesions primarily in the ventromedial hypothalamic nuclei had significantly elevated plasma insulin levels and carcass fat content despite normoglycemia, normophagia and normal to reduced body weight gain. The results indicate the existence in the rat hypothalamus of a locus limited to the region of the ventromedial nuclei which affects insulin secretion and lipogenesis. The possible mechanisms responsible for this phenomenon are discussed.
The anatomy of the brain of the bottlenose dolphin (Tursiops truncates). Rhinic lobe (rhinencephalon). I. The paleocortex
Authors: Jacobs Myron S. , Morgane P. J. , McFarland Willard L.
Published: December 2004

The bottlenose dolphin, Tursiops truncatus, lacks olfactory bulbs and peduncles as do the other members of the odontocete suborder of Cetacea. Nevertheless the dolphin as well as the other cetacean species studied possess a rhinencephalon or rhinic lobe consisting of prominent olfactory lobes and a very reduced hippocampus covered over, respectively, by small epistriatal (frontal, especially orbital lobes and insula) and huge epihippocampal (parietal, occipital and temporal lobes) Portions of the hemisphere.

In the dolphin the demarcation of the rhinic lobe from each hemisphere bilaterad to it is particularly clear and consists of a continuous circular groove (rhinic cleft) composed of posterior parolfactory, anterior and posterior rhinal, rhinohippocampal, hippocampal and callosal segments. Along the trajectory of the rhinic cleft, the cytoarchitectonic demarcation of the paleocortex (olfactory lobes) and archicortex (hippocampus) from the neocortex in the border (limbus) of each hemisphere is equally clear. The rhinic lobe in Tursiops and other Cetacea so far examined thus appears to be a formation of the telencephalon whose distinctness in these species is dramatically emphasized.

Topographic disposition of the cytoarchitectonic areas of the paleocortex in Tursiops, Which have not heretofore been described, has been found in this study to be essentially similar to that of other placental mammals. These areas of the paleocortical division of the rhinic lobe (Prepyriform, tubercular, diagonal and periamygdalar areas) are as easily differentiated from one another in this species as in many other mammalian forms.