bluuebunny/crossref_metadata_2025_split huggingface dataset:
Separation as a natural cue to danger in the spotted hyena (Crocuta crocuta)
Authors: Rifkin Anne , Glickman Stephen E. 
Published: March 2004

AbstractSpotted hyena biology suggests mothers and infants will exhibit one of two alternative responses to separation: (a) Due to prolonged dependency, infants will act similarly to Old World monkeys, displaying distress and proximity seeking behaviors; or (b) because mother–infant separations are frequent in the wild, infants will exhibit little distress or change in reunion behavior. Hence, reunion behavior following mother–infant separation was compared to control periods in captive hyena (Crocuta crocuta) mothers and infants at two developmental periods. Significant increases (p ≤ .05) in distress (i.e., agitated arousal and increased vocalization) and proximity maintenance (i.e., cub and maternal approaches, and maternal monitoring) as well as a trend towards increased sibling aggression following separation were observed. Responsibility for proximity maintenance, assessed by the Hinde Index, adhered to patterns common to primates—with cubs assuming increased responsibility later in development. Findings are discussed in light of hyena ecology and Attachment Theory. © 2004 Wiley Periodicals, Inc. Dev Psychobiol 44: 199–207, 2004.
The antidiabetic agent, gliclazide, reduces high insulin–enhanced neutrophil‐transendothelial migration through direct effects on the endothelium
Authors: Okouchi Masahiro , Okayama Naotsuka , Omi Hitoshi , Imaeda Kenro , Fukutomi Tatsuya , Nakamura Atsushi , Itoh Makoto 
Published: March 2004

AbstractBackground and aimMany lines of evidence indicate that hyperinsulinemia might be associated with coronary athrosclerosis, and, currently, there are no effective strategies for preventing this. We previously reported that high insulin enhances neutrophil‐transendothelial migration, a process that involves increased surface presentation of platelet endothelial cell adhesion molecule‐1 (PECAM‐1) through a mitogen‐activated protein (MAP) kinase–dependent event. In this current study, we examined if antidiabetic agents, especially KATP channel blockers, might similarly protect against the leukocyte‐endothelial cell interactions enhanced by high insulin.MethodsNeutrophils transmigration across umbilical vein endothelial cells (in high insulin medium) with or without KATP channel blockers was performed. Neutrophil migration was quantified by measuring myeloperoxidase, and surface expression of endothelial PECAM‐1 was examined using cell‐surface enzyme immunoassay.ResultsNeutrophil‐transendothelial migration and PECAM‐1 expression were enhanced by insulin (100 µU/mL, 24 h) and were attenuated by gliclazide (20 µM), but not by other KATP channel blockers (glibenclamide, nateglinide, and glimepiride). Neutrophil migration and PECAM‐1 expression were also increased by the mitogen‐activated protein (MAP) kinase activator, anisomycin (1 µM), and also attenuated by gliclazide. Nitric oxide (NO) synthase inhibitors did not modify either gliclazide effect.ConclusionsOur results suggest that the KATP channel blocker, gliclazide, blocks high insulin–mediated neutrophil migration and PECAM‐1 expression. These gliclazide effects may be mediated through the inhibition of MAP kinase activation and are unrelated to NO production. Copyright © 2004 John Wiley & Sons, Ltd.
LDL oxidative modifications in well‐ or moderately controlled type 2 diabetes
Authors: Scheffer P. G. , Henry R. M. A. , Wever E. J. M. , van Rooij G. J. , Bos G. , Heine R. J. , Dekker J. M. , Diamant M. , Stehouwer C. D. A. , Nijpels G. , Blankenstein M. A. , Teerlink T. 
Published: March 2004

AbstractBackgroundThe aim of the study was to examine, by measurement of specific indicators of free radical‐mediated oxidation of LDL, whether there is evidence of increased in vivo oxidation of LDL in type 2 diabetic patients, and to investigate their associations with carotid intima media thickness (IMT).MethodsIn native LDL, we quantified five different products of LDL oxidation reflecting various stages of LDL oxidative modification in 38 individuals with well‐ or moderately controlled type 2 diabetes (HbA1c ≤ 8.5%) and 38 gender‐matched subjects with normal glucose metabolism. Baseline conjugated dienes (BCD), 7‐OH‐glycero‐phosphocholine (7‐OH‐GPC), lyso‐phosphatidylcholine (lyso‐PC), and ketocholesterol were determined in LDL, and circulating in vivo oxidized apolipoprotein B100 (Ox‐apoB) was measured in plasma. The IMT of the carotid artery was measured by ultrasound.ResultsBorderline higher carotid IMT values were observed in individuals with diabetes (0.88 ± 0.14 vs 0.83 ± 0.11 mm, p = 0.06). LDL‐ketocholesterol (45.5 ± 19.4 vs 37.1 ± 13.8 nmol/mmol LDL‐cholesterol, p < 0.05) and Ox‐apoB (25.3 ± 5.5 vs 22.2 ± 5.8 U/mmol LDL‐cholesterol, p < 0.05) were significantly increased in diabetic patients. The concentration of BCD, 7‐OH‐GPC and lyso‐PC in LDL did not differ between diabetic patients and control subjects. No significant correlations were demonstrated between the measured indicators of LDL oxidation and carotid IMT.ConclusionLevels of BCD, 7‐OH‐GPC and lyso‐PC, that is, intermediary products of LDL oxidation, were not significantly elevated, but ketocholesterol and Ox‐apoB, that is, stable end products of the oxidation process, were increased in diabetic patients. We conclude that in vivo oxidation of LDL is increased, even in subjects with well‐ or moderately controlled type 2 diabetes. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis and Monitoring of α‐Bi2Mo3O12 Catalyst Formation using Thermo‐Raman Spectroscopy
Authors: Ghule Anil , Tzing Shin‐Hwa , Chang Jia‐Yaw , Ghule Kalyani , Chang Hua , Ling Yong Chien 
Published: March 2004

AbstractThermo‐Raman spectroscopy was used to monitor the dehydration and phase transformations of Bi2Mo3O12·5H2O. The hydrated forms Bi2Mo3O12·5H2O, Bi2Mo3O12·4.75H2O, Bi2Mo3O12·3H2O, Bi2Mo3O12·2H2O, and anhydrous Bi2Mo3O12 were observed during dehydration in the wavelength range from 200 to 1400 cm−1. Representative Raman spectra of these compounds are reported for the first time. The thermo‐Raman intensity thermogram showed a systematic dehydration in four steps, and the differential thermo‐Raman intensity thermogram confirmed this. Thermogravimetry, differential thermogravimetry, and differential scanning calorimetry results were in harmony with the results of the thermo‐Raman spectroscopy. Additionally, the dehydration resulting in formation of anhydrous Bi2Mo3O12 (amorphous Bi2Mo3O12 phase) and the final transformation into the α‐Bi2Mo3O12 phase was observed to be a dynamic thermal process. The slow, controlled heating rate produced α‐Bi2Mo3O12 catalyst with a particle size averaging 200 nm. The catalyst formed was further characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, time of flight SIMS, transmission electron microscopy, and energy‐dispersive X‐ray analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Structural Study of Novel Graphite−Lithium−Calcium Intercalation Compounds
Authors: Pruvost Sébastien , Hérold Claire , Hérold Albert , Lagrange Philippe 
Published: March 2004

AbstractThree new layered compounds were synthesised by immersing a pyrographite platelet in a molten Ca−Li alloy creating a new graphite intercalation compound family. The samples were studied by X‐ray and neutron diffraction, revealing that the intercalated sheets are polylayered. The study of the 00l reflections allowed us to establish the c‐axis stacking of these three phases. The α‐phase exhibits a five‐layered intercalated sheet which has something in common with a Li−Ca−Li−Ca−Li slice cut in the CaLi2 structure (ThMn2 Laves phase type). The β‐phase, which is richer in metallic elements and with a greater repeat distance, possesses seven‐layered intercalated sheets due to the splitting of the middle lithium plane in three. The third phase is a pseudo‐binary compound, containing monolayered sheets and with a formula close to CaC6. Electron microdiffraction allowed us to determine the 2D unit cell for each compound, all of which were commensurate with that of graphite. Charge transfer from the intercalate to the host lattice was evaluated for the three phases from hk0 data, leading to high values. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Reactivity of a Phosphanylalane Complex towards Lewis Bases
Authors: Vogel Ulf , Schwan Karl‐Christian , Scheer Manfred 
Published: March 2004

AbstractThe reactivity of the Lewis acid/base stabilized complex of phosphanylalane [(CO)5W(H2PAlH2·NMe3)] (1) towards the Lewis bases THF and NMe3 has been investigated. The reaction with THF leads to decomposition of the complex. One of the decomposition products was identified as containing the anion [{(CO)5W}2PH2]− (2). This anion could be synthesized independently by reaction of [(CO)5WPH3] with KH in the presence of [(CO)5W(THF)] and was isolated as the tetraphenylphosphonium salt [Ph4P][{(CO)5W}2PH2] (2a). The treatment of 1 with NMe3 leads to the formation of [(CO)5W(H2PAlH2·2 NMe3)] (3) containing a five‐coordinate aluminum atom. Compound 3 exhibits a fast exchange of the NMe3 ligands in solution containing an excess of NMe3. The products were characterized by spectroscopic methods and X‐ray crystallography. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Rotaxanes and Catenanes Built Around Octahedral Transition Metals
Authors: Chambron Jean‐Claude , Collin Jean‐Paul , Heitz Valérie , Jouvenot Damien , Kern Jean‐Marc , Mobian Pierre , Pomeranc Didier , Sauvage Jean‐Pierre 
Published: March 2004

AbstractTransition metals are extremely useful tools for the preparation of rotaxanes and catenanes. Traditionally, copper(I) has played an important role in this field, but recently octahedrally coordinated metal centres such as ruthenium(II), have allowed the preparation of highly functional interlocking ring systems. The present review article will discuss this new approach, which gives access to novel rotaxanes and catenanes. Besides the purely synthetic work described, the potential of the prepared compounds to be used as light‐driven molecular machines will be mentioned. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Chemistry of Thiacalixarenes
Authors: Lhoták Pavel 
Published: March 2004

AbstractThiacalixarenes — new members of the calixarene family — are very promising molecules with many potential applications in supramolecular chemistry. The presence of four sulfur atoms in the place of methylene groups imparts many novel features and properties to these molecules. This review deals with the chemistry of thiacalixarenes, and by comparision with “classical” calixarenes, emphasizes their differences in reactivity, unusual conformational preferences and modified complexation abilities. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Non‐Rusty [2]Catenanes with Huge Rings and Their Polymers
Authors: Godt Adelheid 
Published: March 2004

AbstractWe describe the design and synthetic realisation of [2]catenanes characterised by having huge rings that can rotate freely and shift laterally within the constraints of concatenation. The synthetic strategy, which is based on using a carbonate group as a covalent template and oxidative dimerization of alkynes to achieve ring formation, is versatile with respect to ring size and the presence of functional groups. The monocyclic constitutional isomer of the catenane is available by a simple exchange of steps in the sequence. EPR spectroscopy revealed that in solution the catenanes adopt all possible co‐conformations in equal abundances. The thermotropic liquid crystallinity of the [2]catenanes and their corresponding non‐intertwined macrocycles proves intermolecular ordering in the bulk phase. The [2]catenanes were polymerized through ester formation and through acyclic diene metathesis. All of the poly[2]catenanes have rather low degrees of polymerisation (<Pn> ≈︁ 10), possibly because cyclisation occurs. For the preparation of [n]catenanes having n > 3, we propose fusing the rings of [2]catenanes so that the crucial steps of threading and cyclisation need only occur during the synthesis of the smallest catenane. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Transition Metal‐Catalyzed Carbon−Carbon Bond Formation with Grignard Reagents − Novel Reactions with a Classic Reagent
Authors: Shinokubo Hiroshi , Oshima Koichiro 
Published: March 2004

AbstractOrganomagnesium compounds are among the most useful organometallic reagents in organic synthesis. Besides their classical nucleophilic reactions to carbonyl compounds, Grignard reagents gain versatile reactivity when combined with various transition metal salts. In this article, we review mainly our own studies on manganese‐, iron‐, chromium‐, and cobalt‐catalyzed carbon−carbon bond formation reactions using Grignard reagents. Other closely related research in this field is also discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
A Study of the Determination of Cu(II) by Anodic Stripping Voltammetry on a Novel Nylon/Carbon Fiber Electrode
Authors: Mylonakis A. , Economou A. , Fielden P. R. , Goddard N. J. , Voulgaropoulos A. 
Published: March 2004

AbstractIn this work we report a new electrode material formed by injection‐moulding of a conducting polymer consisting of carbon fibers in a Nylon matrix. This material is highly conductive, inexpensive, easy to mould in different shapes and requires minimal pretreatment. The electrode was tested as a mercury‐free sensor for the trace determination of Cu(II) by anodic stripping voltammetry (ASV). The deposition and stripping behavior of copper on the conducting material was initially studied by cyclic voltammetry and the chemical and instrumental parameters of the determination were investigated. The electrode has been shown to be suitable for the determination of Cu(II) in the range 8 μg L−1 to 30 mg L−1 (with deposition times ranging from 30 s to 10 min) with a relative standard deviation of 2.2% (at the 0.5 mg L−1 level) and a limit of detection of 8 μg L−1 Cu(II) for 10 min of accumulation (at a S/N ratio of 5). The electrode was, finally, applied to the determination of copper in tap‐water, pharmaceutical tablets and bovine serum with recoveries of 97.4, 94.9 and 93.4%, respectively
Novel Ni(II) Mixed Ligand Complex Modified Electrode: Catalytic Effect on Anodic Oxidation of Phenol
Authors: Mohan Jegan , Joshi Seema , Prakash Rajiv , Srivastava R. C. 
Published: March 2004

AbstractCyclic voltammetry, using graphite paste electrode (GPE) and chemically modified GPE with Ni(II) mixed ligand complex (MGPE), is described for sensing and detoxification of phenol. A novel mixed ligand complex of nickel with 1,4,8,11‐tetraaza cyclotetradecane (cyclam) and thiocyanate in the molar ratio of 1 : 2 : 5 is synthesized and characterized by spectroscopic and electrochemical studies. The Ni(II)‐cyclam‐thiocyanate complex behaves as a fast electron‐transfer mediator, as nickel ions exist in higher oxidation state of Ni(III) on applying a potential of 1.25 V (vs. Ag/AgCl), which catalyses the oxidation of the target species. The mixed ligand complex, when incorporated in the graphite paste electrode, is sensitive to detect phenol as low as 10 μg/L in solution. The catalytic effect of the Ni(II)‐cyclam‐thiocyanate complex enhanced many folds the oxidation of phenol compared to GPE. The technique has potential for sensing/monitoring and detoxification of phenol released in the ecosystem from polluting industries.
A Simulation of an Anion‐Induced Adsorption of Metal Ions in Pseudopolarography Using a Thin Mercury Film Covered Rotating Disk Electrode
Authors: Omanović Dario , Lovrić Milivoj 
Published: March 2004

AbstractA theory of the influence of anion‐induced adsorption of metal ions in pseudopolarography using the thin mercury film covered rotating disk electrode is developed. The model is developed assuming that the metal ion is forming several labile complexes with the ligand which is present in a great excess, and that only one complex species is adsorbed following a linear isotherm. The results obtained assuming steady‐state conditions are compared with the simulation of transient processes using Galerkin and finite difference methods. It is shown that the adsorption of metal complexes on the disk electrode surface does not prevent the determination of the stability constants.
Construction and Characterization of a New Flexible and Nonbreakable Nitric Oxide Microsensor
Authors: Dickson Alec , Lin Jie , Sun Jie , Broderick Mark , Fein Harry , Zhang Xueji 
Published: March 2004

AbstractNitric oxide (NO) is an important molecule in many different physiological phenomena. Investigation of nitric oxide production in vivo requires a specialized sensor capable of real‐time concentration measurement, with a high spatial resolution of NO gas production. In this study, a flexible microsensor is developed specifically for measurement of production of nitric oxide. The new sensor consists of a Pt/Ir working electrode coupled with an integrated Ag/AgCl reference electrode. The sensor is coated with a series of NO‐selective membrane polymers to prevent potential amperometric response due to interfering species. Presented experimental data demonstrates the ability for NO detection between 100 and 400 nM concentrations with a linear response (R2=0.9997). The detection limit of the sensor is 2.14 nM (S/N=3). Various selectivity experiments are indicative of a resistance to interfering species such as dopamine, norepinephrine, L‐arginine.
Heterogeneous ECE Processes at Channel Electrodes: Analytical Solution for all Reaction Rate Constants and Different Diffusion Coefficients
Authors: Zhang Jinsuo , Li Ning 
Published: March 2004

AbstractAn analytical solution is developed for heterogeneous ECE processes occurring at channel electrode surface for both laminar and turbulent flow. The solution explicitly links the behavior of ECE processes and the parameters. A simple expression of the effective number of electrons transferred, covering all the reaction rate constants and different diffusion coefficients of the reactant A and the intermediate product B, is obtained. Excellent agreement with previous numerical and analytical results is shown . Parametric studies illustrate the effects of diffusion coefficients, hydrodynamic factors and reaction rate constants on the effective number of electrons transferred and the currents.
Voltammetric Behavior of Mifepristone (RU‐486) Using Square‐Wave and Adsortive Stripping‐Wave Techniques. Determination in Urine Samples
Authors: Rodríguez J. , Berzas J. J. , Castañeda G. , Rodríguez N. 
Published: March 2004

AbstractThe behavior of Mifepristone (RU‐486) was studied by square‐wave technique, leading to two methods for its determination in aqueous samples and urine samples at pH 2. The application of the square‐wave (SW) without the adsorptive accumulation and stripping voltammetric (AdSV) show the maximum response at −0.896 V using an accumulation potential of −0.5 V. The effect of experimental parameters that affect this determination are discussed. For the stripping technique, Mifepristone proved to be more sensitive, yielding signals four times larger than those obtained by applying a square‐wave scan without the previous accumulation. The calibration plot to determine Mifepristone was linear in the range 2.4×10−8 and 5.4×10−7 M by stripping mode with an accumulation time tacc of 30 s. The relative standard deviation obtained for concentration levels of Mifepristone as low as 2.0×10−7 M with square‐wave was 1.17% (n=10) and with stripping square‐wave 2.02% (n=10) in the same day. The two proposed methods (SW and SWAdSV) were applied to the determination of Mifepristone in urine.
Carbon Paste Electrode Modified with Carbamoylphosphonic Acid Functionalized Mesoporous Silica: A New Mercury‐Free Sensor for Uranium Detection
Authors: Yantasee Wassana , Lin Yuehe , Fryxell Glen E. , Wang Zheming 
Published: March 2004

AbstractThis study reports a new approach for developing a uranium electrochemical sensor that is mercury‐free, solid‐state, and has less chance for ligand depletion than existing sensors. A carbon‐paste electrode modified with carbamoylphosphonic acid self‐assembled monolayer on mesoporous silica was developed for uranium detection based on an adsorptive square‐wave stripping votammetry technique. Voltammetric responses for uranium detection are reported as a function of pH, preconcentration time, and aqueous phase uranium concentration. The uranium detection limit is 25 ppb after 5 minutes preconcentration and improved to 1 ppb after 20 minutes preconcentration. The relative standard deviations are normally less than 5%.
Voltammetry as a Virtual Potentiometric Sensor in Modeling of a Metal‐Ligand System and Refinement of Stability Constants. Part 1. Polarographic and Glass Electrode Potentiometric Study of a Dynamic Cd‐Glycine System
Authors: Cukrowski Ignacy , Zhang Jian Min 
Published: March 2004

AbstractA mathematical conversion of data coming from nonequilibrium and dynamic voltammetric techniques (a direct current sampled (DC) and differential pulse (DP) polarography) into potentiometric sensor type of data is described and tested on a dynamic metal‐ligand system. A combined experiment involving DCP, DPP and glass electrode potentiometry (GEP) was performed on a single solution sample containing a fixed [LT] : [MT] ratio (acid‐base titration). Dedicated potentiometric software ESTA was successfully employed in the refinement operations performed on virtual potentiometric (VP) data obtained from DC and DP polarography. It was possible to refine stability constants either separately, from VP‐DC or VP‐DP, or simultaneously from any combination of VP‐DC, VP‐DP and GEP. The concept of VP‐DC or VP‐DP is reported for the first time and numerous documented and possible advantages are discussed. The proposed procedure can be easily utilized also by nonelectrochemists who are interested in, e.g., the ligand design strategies.
Voltammetric and Differential Pulse Stripping Study of Adenine on a Sol‐gel Derived Carbon Composite Electrode
Authors: Teh Huey Fang , Yang Xinhao , Gong Haiqing , Tan Swee Ngin 
Published: March 2004

AbstractThis communication reports on the electrochemical investigation of adenine on a sol‐gel carbon composite electrode (CCE). Cyclic voltammetric (CV) technique is used to characterize the redox behavior of adenine at CCE. The peak current and peak potentials are dependent on the pH of the buffer solution. From the scan rate and peak current study, there is evidence of adsorption of adenine on the CCE. The parameters affecting the differential pulse stripping adsorption peak were systematically optimized. Under optimum conditions of Eacc=−0.10 and tacc=60 s, a linear calibration plot was obtained, 2×10−7–1×10−6 M. This CCE is useful for the simultaneous analysis of adenine and guanine from denatured DNA.