bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of sediment deposits from Namibian diamond mines on intertidal and subtidal reefs and rock lobster populations
Authors: Pulfrich Andrea , Parkins Colleen A. , Branch George M. , Bustamante Rodrigo H. , Velásquez Claudio R. 
Published: April 2003

Abstract
Extensive diamond mining occurs on land and in the sea on the west coasts of South Africa and Namibia, raising fears that diamond‐mining activities may impact commercial rock‐lobster fisheries and benthic communities. To explore this possibility, the effects of the diamond‐mining fines‐discharge on intertidal and subtidal rocky‐shore communities and on the population structure of the rock lobster Jasus lalandii were assessed at Elizabeth Bay.
Sampling over six years at sites covering a range of wave exposures compared impacted sites with comparable reference sites never exposed to the fines. Percentage cover and densities of benthic organisms were recorded on both intertidal and subtidal reefs. Rock‐lobster abundance was estimated from counts and catch‐per‐unit‐effort, and their length frequencies and sex ratios compared in impacted and reference areas.
The deposition of fines had no effect at wave‐exposed sites, but did impact intertidal and subtidal communities at sheltered localities where fines accumulated because wave action was insufficient to disperse them. Reductions of grazers, proliferation of algae and increased dominance by filter‐feeders were recorded at the impacted sites and persisted throughout the monitoring programme. Differences in community structure associated with different levels of wave exposure were, however, greater than those produced by depositing fines. The detected effects of fines‐deposits on the benthos were local and likely to be reversible after cessation of mining.
The fines‐deposit had no detectable effects on the sex‐ratio, size or abundance of rock lobsters, indicating that there is no conflict between the deposition of fines and the fishery for rock lobsters, although substantial inter‐site variability makes it difficult to regard the results as definitive.
Copyright © 2002 John Wiley & Sons, Ltd.
Intracerebroventricular injection of the terminal complement complex causes inflammatory reaction in the rat brain
Authors: Casarsa Claudia , Luigi Ada De , Pausa Mario , Simoni Maria Grazia De , Tedesco Francesco 
Published: April 2003

AbstractTo investigate the effect of the terminal complement complex (TCC) on the central nervous system, we injected both the cytolytically active and the inactive complexes into the lateral ventricle of rats. Both complexes promoted accumulation of leukocytes into the cerebrospinal fluid at 4–6 h post‐injection. The cells recovered at this time were mostly polymorphonuclear leukocytes (PMN) that were partially replaced by mononuclear cells at 12 h. A direct contribution of the complexes to the in‐vivo migration of leukocytes was ruled out by their inability to be chemotactic for rat PMN. Contaminating C5a is unlikely to be responsible for the effect of TCC because it failed to mobilize leukocytes when injected into the lateral ventricle. Histological analysis of rat brains 6 hoursafter injection of TCC revealed marked leukocyte infiltration of the choroid plexus, increased expression of intercellular adhesion molecule‐1 and egression of leukocytes out of the meningeal vessels. The cerebrospinal fluid of rats treated with TCC exhibited chemotactic activity for rat PMN and increased levels of growth related oncogen/cytokine‐induced neutrophil chemoattractant‐1 and monocyte chemoattractant protein‐1 preceding the accumulation of leukocytes. Elevated concentration of IL‐1β was also found in the cerebrospinal fluid and in periventricular areas of rats treated with TCC.
Organ‐specific and stage‐dependent control of Leishmania major infection by inducible nitric oxide synthase and phagocyte NADPH oxidase
Authors: Blos Martin , Schleicher Ulrike , Rocha F. Janaina Soares , Meißner Udo , Röllinghoff Martin , Bogdan Christian 
Published: April 2003

AbstractIn the Leishmania major mouse model of cutaneous leishmaniasis inducible nitric oxide synthase (iNOS) is crucial for the killing of the parasite in the skin and draining lymph node. However, the effector mechanism operating against L. major in the spleen is unknown. As reactive oxygen intermediates might play a role, we analyzed macrophages and mice lacking the gp91phoxsubunit of the phagocyte NADPH oxidase (phox) for their ability to combat an infection with L. major. Macrophages from wild‐type and gp91phox–/– mice had an equal capacity to killL. major after activation by cytokines. Unlike iNOS, the activity of phox was dispensable for the resolution of the acute skin lesions and exerted only a limited effect on the containment of the parasites in the draining lymph node, but was essential for the clearance of L. major in the spleen. During the chronic phase of infection, parasites persisted at high levels in gp91phox–/– mice, and cutaneous lesions re‐emerged in approximately 60% of these mice. gp91phox deficiency did not impair the expression of iNOS or the production of TNF and IFN‐γ. These results demonstrate that iNOS and phox are both required for the control of L. major in vivo and display unexpected organ‐ and stage‐specific anti‐leishmanial effects.
Low‐avidity recognition by CD4+ T cells directed to self‐antigens
Authors: Gebe John A. , Falk Ben A. , Rock Kellee A. , Kochik Sharon A. , Heninger Anne K. , Reijonen Helena , Kwok William W. , Nepom Gerald T. 
Published: April 2003

AbstractSelf‐reactive T cells populate the peripheral immune system, and likely form the reservoir from which autoreactive cells are derived. We analyzed a panel of self and non‐self peptides presented by HLA‐DR4, a class II molecule associated with autoimmunity, by immunization of mice transgenic for HLA‐DR4. Significant structural avidity for T cell recognition, as measured by MHC class II tetramer binding to CD4+ T cells was only observed in mice immunized with the non‐self antigens. T cell hybridomas were generated from mice immunized with the naturally processed self‐peptide hGAD65 (552–572) and also from mice immunized with an influenza‐derived non‐self epitope (HA 306–318). T cells specific for the self peptide failed to bind tetramers and exhibited low functional avidity as measured by the peptide concentration required to reach half‐maximum proliferation values. In contrast, T cells specific for the non‐self HA (306–318) peptide exhibited high structural and functional avidity profiles. As recently described in studies of murine CD8+ T cell function, the predominance of low avidity recognition of self‐peptide epitopes may be a characteristic feature of CD4+ T cells responding to autoantigens.
Selective cross‐talk among natural cytotoxicity receptors in human natural killer cells
Authors: Augugliaro Raffaella , Parolini Silvia , Castriconi Roberta , Marcenaro Emanuela , Cantoni Claudia , Nanni Marina , Moretta Lorenzo , Moretta Alessandro , Bottino Cristina 
Published: April 2003

AbstractThe cytolytic activity of human natural killer cells is induced by several triggering cell surface receptors upon interaction with specific cellular ligands. These receptors include NKp46, NKp30 and NKp44, collectively termed natural cytotoxicity receptors (NCR). Co‐operation among NCR has been shown to occur for optimal recognition and killing of most tumor target cells. In this study, we show that the mAb‐mediated engagement and clustering of one or another NCR results in the activation of an identical set of tyrosine kinases. These kinases are included in the signaling cascade leading to tyrosine phosphorylation of different receptor‐associated signal transducing molecules i.e. CD3ζ (associated with NKp46 and NKp30) and KARAP/DAP12 (associated with NKp44). In line with the notion that the engagement of inhibitory receptors prevents NCR‐mediated responses, we show that the engagement of CD94/NKG2A virtually abrogates the tyrosine phosphorylation of the NCR‐associated signaling molecules, i.e. it acts at the very early steps of the signaling cascade. Importantly, the engagement of a single NCR resulted in the activation of the signaling cascades associated with the other NCR. This "cross‐talk" is confined to NKp46, NKp30 and NKp44 since neither CD16‐nor KIR2DS4‐associated signaling polypeptides were phosphorylated following the NCR engagement. These results suggest that a functional cross‐talk specifically occurs among different NCR, possibly resulting in the amplification of the activating signals.
Cobalt(III) Tetraazamacrocyclic Complexes with Pendant Amino Groups: Synthesis, Structure and Electrochemical Properties
Authors: Korybut‐Daszkiewicz Bohdan , Taraszewska Joanna , Zięba Katarzyna , Woźniak Krzysztof , Kamiński Daniel 
Published: April 2003

AbstractTwo isomeric cis‐2,9‐bis(aminomethyl)‐5,7,7,12,14,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane (1 and 2) and two 2‐aminomethyl‐2‐methyl‐1,4,8,11‐tetraazacyclotetradecane (3 and 4) cobalt(III) complexes have been prepared and characterised. During the synthesis of 2 a minor oxidation product 5 was formed. The structures of 3, 4 and 5 have been determined by X‐ray crystallography, and the UV/Vis spectra of 1−5 have been analysed. The average Co−N distances in 1 and 2 have been estimated from the correlation between the average Co−N bond lengths and position of the maximum absorption for hexaamine complexes given in literature. The electrochemical behaviour of 1−5 in neutral and acidic solutions has been studied by cyclic voltammetry. In complexes displaying electronic maxima at higher energy, cobalt(III) was reduced at more negative potentials. Small differences in the conformation of ligand between 3 and 4 explain the different behaviour of these complexes in acidic solutions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Novel P,N Ligands Derived from (R)‐ and (S)‐1‐Phenylethylamine with (2R,5R)‐2,5‐Dimethylphospholanyl Groups (DuPHAMIN) for Asymmetric Catalysis
Authors: Brauer David J. , Kottsieper Konstantin W. , Roßenbach Stefan , Stelzer Othmar 
Published: April 2003

AbstractNovel P,N chelating ligands with three stereogenic centres in positions α to the donor atoms have been prepared in good yields and high enantiomeric purity by a series of reactions beginning with either (R)‐ or (S)‐1‐phenylethylamine. These isomers were first lithiated with tBuLi and converted into aminophosphanes 3a by treatment with (Et2N)2PCl. They were transformed into the enantiomeric primary phosphanes 4 by quantitative solvolysis with ethanol to give the phosphonous acid esters 3b and subsequent reduction with LiAlH4. Stepwise treatment of 4 with nBuLi and the cyclic sulfate of (S,S)‐2,5‐hexanediol gave the isomeric tertiary phosphanes (R,RR)‐5 and (S,RR)‐5. Treatment of the aminophosphane (R)‐3a with (R)‐2,2′‐binaphthol yielded the aminophosphonite (R,R)‐6 in high yields. Cationic (COD)Rh complexes of 5 were prepared by treatment with [Rh(COD)Cl]2, the PF6− salts 7a being isolated. Analogous (2,5‐norbornadiene)Rh complexes 7b were prepared similarly. The chelate nature of the P,N ligands in these salts is indicated by their NMR spectra in solution and is confirmed by the crystal structures of (R,RR)‐7a and (S,RR)‐7a. With the exception of (S,RR)‐7a, the complexes 7a and 7b are shown to catalyse the asymmetric hydrogenation of methyl acetamidocinnamate at room temperature. Differences in the catalytic activity of the complexes are related to the different dynamic behaviour detected by the 1H EXSY spectra for the COD ligands of 7a. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
CuII Ion Coordination to an Unprotected Pentadecapeptide Containing Two His Residues: Competition Between the Terminal Amino and the Side‐Chain Imidazole Nitrogen Donors
Authors: Conato Chiara , Kamysz Wojciech , Kozłowski Henryk , Łuczkowski Marek , Mackiewicz Zbigniew , Mancini Francesca , Młynarz Piotr , Remelli Maurizio , Valensin Daniela , Valensin Gianni 
Published: April 2003

AbstractThe complex‐formation equilibria of the pentadecapeptide TLEGTKKGHKLHLDY, the 114−128 protein fragment of SPARC, with the CuII ion have been investigated, at I = 0.1 mol·dm−3 (KNO3) and T = 298.2 K. Protonation and complex‐formation constants have been determined potentiometrically, and formation enthalpies measured by direct solution calorimetry; the complex‐formation model and species stoichiometry have been carefully checked by means of UV/Vis absorption, CD and EPR spectroscopy. The structure hypotheses of the complex species are also based on detailed study of the 1H and 13C NMR spectra of the ligand in both the absence and presence of copper ions. The involvement in complex‐formation of both the terminal amino and imidazole groups has been suggested and their specific behaviour at different pH values elucidated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Metal‐Controlled Stereoselectivity in Complex Formation: Assembly of Tetranuclear Copper(I) Complexes with Four Stereogenic Nitrogen Donor Functions in all‐(R) and all‐(S) Configurations
Authors: Schneider Jörg , Köckerling Martin , Kopitzky Rodion , Henkel Gerald 
Published: April 2003

AbstractThe reaction of N,N′‐dialkyl‐3,7‐diazanonane‐1,9‐dithiolate (NR2S2) ligands (R = Me, Et) with monovalent copper resulted in the formation of the chiral complexes [Cu4(NMe2S2)2] (1) and [Cu4(NEt2S2)2] (2) which were characterised by means of X‐ray diffraction and spectroscopic techniques. They contain copper atoms in both linear {S−Cu−S} fragments, which act as linkers between mononuclear [Cu(NR2S2)]− subsites, and in {CuS2N2} units within these building blocks, which can be described as incomplete coordination octahedra of unusual design. Due to favourable interplay between the spatial demands of the ligand system and the electronic requirements of the copper atom, the nitrogen donor atoms within the [Cu(NR2S2)]− metallo ligands are restricted to identical absolute configurations. The combination of two [Cu(NR2S2)]− metallo ligands with two further CuI ions to give the tetranuclear complexes 1 or 2 via S−Cu−S bridges underlies stereochemical control, resulting in optically active systems with (R,R,R,R) and (S,S,S,S) configurations. Consequently, metallo ligands in their enantiomeric forms cannot combine via S−Cu−S bridges to form optically inactive meso complexes with the (R,R,S,S) configuration. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis, Structure, and Catalytic Activity of New μ‐Oxo‐Bridged Diiron(III) Complexes
Authors: Balogh‐Hergovich Éva , Speier Gábor , Réglier Marius , Giorgi Michel , Kuzmann Ernő , Vértes Attila 
Published: April 2003

AbstractThe preparation and characterisation of two dinuclear iron(III) complexes with tripodal ligands 1,3‐bis(2′‐pyridylimino)isoindoline (indH) are presented. The μ‐oxo‐bridged diiron(III) complex [{FeCl(ind)}2O] (2) has been prepared by reacting FeCl3·6H2O with indH in methanol solution. Compound [{Fe(ind)(OAc)}2O] (3) was obtained from the reaction of 2 with CH3CO2Ag in THF. Both compounds were characterised by elemental analysis and UV/vis, IR, and Mössbauer spectroscopy. The X‐ray structure analysis of [Fe2O(ind)2Cl2]·THF (2·THF) revealed a distorted trigonal bipyramidal (τ = 0.88) coordination geometry around the iron(III) ion. More importantly, 2 is a good functional model for the activation of small molecules as its 5‐coordinate iron ions can easily coordinate such molecules. This is confirmed by the high catalase‐like activity of 2, transforming 87% of the excess of H2O2 into O2 in 1 min. The complexes exhibited monooxygenase‐like activity using H2O2 as the oxidant and oxidise alkanes to alcohols and ketones in acetonitrile in moderate yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
A Two‐Step Route to Self‐Assembly of CdS Nanotubes via Electrodeposition and Dissolution
Authors: Zhou Shao‐Min  , Feng Yi‐Si , Zhang Li‐De 
Published: April 2003

AbstractPolycrystalline CdS nanotubes (CNTs) were successfully achieved by a two‐step treatment, i.e. (CdS+Cd) nanowires (electrodeposition and sulfuration process in anodic alumina membrane) ⇄ CNTs (dissolution method of removing Cd in 0.5 M HCl). Having been characterized using X‐ray diffraction and scanning electron microscopy, the nanowires, the intermediate products, contain Cd and CdS, and have uniform diameters of about 80 nm and lengths of up to 25 μm, which correspond to the pore size and thickness of the membrane used. The average inner and outer diameters of the as‐obtained CNTs are respectively 40 and 80 nm via transmission electron microscopy. Selected area electronic diffraction, X‐ray diffraction and X‐ray photoelectron energy spectroscopy investigations demonstrate that these CNTs with hexagonal wurtzite polycrystalline structure are pure and stoichiometric. The successful synthesis of these semiconductor CNTs may open up new possibilities for studies of fundamental properties and potential applications of semiconductor nanotubes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Self‐Assembly of Organodiphosphonate, Polyoxomolybdate and Diphenanthrolinecobalt(II) into Two Clusters and One Linear Polymer
Authors: Fu Rui‐Biao , Wu Xin‐Tao , Hu Sheng‐Min , Zhang Jian‐Jun , Fu Zhi‐Yong , Du Wen‐Xin , Xia Sheng‐Qing 
Published: April 2003

Abstract[{Co(1,10‐phen)2}2{(Mo4O12)(O3PCH2CH2PO3)}·(H2O)] (1), [{Co(1,10‐phen)2}2{(Mo4O12)(O3PCH2CH2CH2PO3)}·(1.5H2O)] (2) and [{Co(1,10‐phen)2(H2O)2}{Co(1,10‐phen)2(H2O)}{(Mo5O15)(O3PCH2CH2CH2CH2PO3)}·(6H2O)] (3) were synthesized by self‐assembly of H2O3P(CH2)nPO3H2 (n = 2−4), polyoxomolybdate and [Co(1,10‐phen)2]2+ (1,10‐phen = 1,10‐phenanthroline) under hydrothermal conditions. Compounds 1 and 2 are novel heterometallic hexanuclear clusters, while compound 3 is a new linear polymer. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Ultrasonically Enhanced Voltammetric Analysis and Applications: An Overview
Authors: Banks Craig E. , Compton Richard G. 
Published: April 2003

AbstractUltrasonically enhanced voltammetric measurements have been successfully applied for the detection of a wide range of trace metals. These are reviewed and the beneficial effects of power ultrasound applied to electroanalysis highlighted, most notably the possibility for quantitative analysis in otherwise highly passivating media, where classical electrochemical techniques often fail.
NADH Oxidation Using Carbonaceous Electrodes Modified with Dibenzo‐Dithia‐Diazapentacene
Authors: Munteanu Florentina‐Daniela , Dicu Delia , Popescu Ionel Catalin , Gorton Lo 
Published: April 2003

AbstractThe electrochemical and the electrocatalytic behavior for NADH oxidation of a newly synthesized phenothiazine derivative, 16H,18H‐dibenzo[c,1]‐7,9‐dithia‐16,18‐diazapentacene (DDDP), adsorbed on solid spectrographic graphite and on graphite powder or on zirconium phosphate (ZP), both entrapped in carbon paste, were compared. Experiments using cyclic voltammetry and a rotating disk electrode, performed in different experimental conditions (various pH values and NADH concentrations), showed that i) in the pH range between 4 and 8, the E°' value for DDDP adsorbed on ZP becomes pH independent; ii) in contrast to other redox mediators, adsorption of DDDP on ZP induced a significant negative shift of the E°' value; iii) the reaction rate for electrocatalytic oxidation of NADH is markedly increased by adsorbing the mediator on ZP, being further improved by the presence of Ca2+ ions in the solution.
Electrocatalytic Properties of Electropolymerized Ni(II)curcumin Complex
Authors: Ciszewski Aleksander , Milczarek Grzegorz , Lewandowska Beata , Krutowski Krzysztof 
Published: April 2003

AbstractThe voltammetric behavior in alkaline solution of a nickel‐based chemically modified electrode (poly‐Ni(II)curcumin) prepared by oxidative electropolymerization of nickel‐curcumin complex for electrooxidation of aliphatic alcohols was investigated by cyclic voltammetry and rotating disk technique (curcumin=1,7‐bis[4‐hydroxy‐3‐methoxyphenyl]‐1,6‐heptadiene‐3,5‐dione). The dependence of the oxidation current on the alcohol concentration and on the number of redox centers Ni(II)/Ni(III) is discussed. From the fact that the oxidation current increases with the increase of film thickness it is evident that the electrocatalytic reaction occurs inside the polymer film. The system examined is a typical example of a redox polymer with 3D properties. It is also concluded that the reaction mechanism of alcohol oxidation is the case, according to the concept of Andrieux and Saveant, where the cross‐exchange reaction is the limiting step. The mechanism of modifying the film formation has also been discussed.
Designing Potentiometric Sensor Materials for the Determination of Organic Ionizable Substances in HPLC
Authors: Nagels Luc J. , Bazylak Grzegorz , Zielinska Danuta 
Published: April 2003

AbstractThis article provides a model to explain the response of liquid membrane type potentiometric electrodes towards organic ions in HPLC systems. The model is a synthesis of data from 7 recent articles from our group on the determination of several classes of compounds (organic acids, amines, beta‐blockers, clenbuterol, mucolytic drugs and aminoalcohols) with potentiometric detection in HPLC. The presented model uses the difference in chemical potential of the analyte ion in the eluent and in the membrane phase as the sensitivity determining factor. Methods used to estimate this difference in chemical potential are compared. For liquid membrane coatings containing no selectively interacting (complex forming) ionophores, this difference could be estimated from calculated log P (lipophilicity) and P (polarizability) values for the analyte ions. If complex forming agents are present, the extra interaction of the analyte ion with the complex forming agent can be estimated via a solvation parameter model. In the latter case, molecular modeling may also be useful.
Studies on Self‐Assembled Alkanethiol Monolayers Formed at Applied Potential on Polycrystalline Gold Electrodes
Authors: Brett Christopher M. A. , Kresak Slavoj , Hianik Tibor , Oliveira Brett Ana Maria 
Published: April 2003

Abstract1‐Dodecanethiol assembly on polycrystalline gold electrodes at fixed positive potentials has been investigated by chronoamperometry and electrochemical quartz crystal microbalance and the films formed characterized by cyclic voltammetry and electrochemical impedance spectroscopy. It was found that 1‐dodecanethiol adsorption on gold is enhanced by application of positive potentials to the electrode surface and that adsorption proceeds faster than in the case of open circuit deposition. Compact defect‐free monolayers of capacitance values of 1.1–1.6 μF cm−2 are produced in time intervals as short as 100 s, with no roughness, as demonstrated for the first time by electrochemical impedance analysis. Control of surface potential during alkanethiol assembly appears to improve monolayer quality and to allow for shorter assembly periods. Monolayers can be removed by cycling in alkaline solution or in dilute sulfuric acid. These results are important for the fast construction of defect‐free bilayers.