bluuebunny/crossref_metadata_2025_split huggingface dataset:
HPLC–SPE–NMR hyphenation in natural products research: optimization of analysis of Croton membranaceus extract
Authors: Lambert Maja , Stærk Dan , Hansen Steen Honoré , Jaroszewski Jerzy W. 
Published: July 2005

AbstractThe HPLC–SPE–NMR technique was used for the analysis of a root‐bark extract of Croton membranaceus. The components of the extract were separated on an analytical‐size reversed‐phase HPLC column, the chromatographic peaks were trapped on SPE (solid‐phase extraction) cartridges after post‐column dilution of the eluate with water and the compounds were eluted from the cartridges with acetonitrile‐d3 into a 30 µl 600 MHz NMR probe in a fully automated procedure. The trapping efficiency of scopoletin (1), the major extract constituent, was much higher on a GP (general phase, a polystyrene‐type polymer) SPE phase than on a C18 phase. Thus, under the conditions used, up to 100 µg of scopoletin per cartridge could be accumulated linearly after repeated trappings. The maximum achievable NMR signal‐to‐noise ratio using the GP cartridges was at least four times higher than that achievable with the C18 cartridges. It was shown that excessively long T1 relaxation times may compromise experiments in which acetonitrile‐d3 is used as the cartridge eluent. Nevertheless, the sensitivity gain provided by the HPLC–SPE–NMR technique through repeated peak trappings allowed the acquisition of good‐quality proton‐detected 2D NMR spectra without the need for solvent suppression. Copyright © 2005 John Wiley & Sons, Ltd.
HPLC–NMR of fatty alcohol ethoxylates
Authors: Hiller Wolf , Brüll Adele , Argyropoulos Dimitris , Hoffmann Eberhard , Pasch Harald 
Published: July 2005

AbstractThe application of HPLC–NMR for the analysis of a mixture of fatty alcohol ethoxylates (FAEs) is described. The use of the new generation, cryogenically cooled probes is investigated in respect of the sensitivity advantage that they provide. The FAE mixture is separated using liquid chromatography at the critical point of adsorption. The ability of the method to differentiate between the different end groups and the degree of polymerization of the mixture constituents is investigated. Both on‐flow and stop‐flow HPLC–NMR techniques were used together with two‐dimensional NMR spectroscopy. The results are compared with those obtained by using an evaporative light scattering detector for the HPLC. Copyright © 2005 John Wiley & Sons, Ltd.
Phytochemistry in the microgram domain—a LC–NMR perspective
Authors: Wolfender Jean‐Luc , Queiroz Emerson F. , Hostettmann Kurt 
Published: July 2005

AbstractPlants represent an extraordinary reservoir of novel molecules and there is currently a resurgence of interest in the vegetable kingdom as a possible source of new lead compounds for introduction into therapeutical screening programs. In order to discover potential new bioactive natural products, the dereplication of crude plant extracts performed prior to isolation work is of crucial importance for avoiding the isolation of a known constituent. In this respect, chemical screening strategies have been developed using hyphenated techniques (LC/UV–DAD, LC–MS and LC–NMR). In our laboratory, these techniques have been fully integrated into the isolation process and are used for the chemical screening of crude plant extracts in complement with on‐line or at‐line bioassays. LC–UV–MS is used as a first dereplication step in combination with UV and MS databases, while LC–NMR is performed in a second step for de novo on‐line structure determination. This approach enables the partial or the complete on‐line identification of natural products in complex matrices such as crude plant extracts. These methods also give a unique possibility to study unstable compounds, which rapidly degrade or which are not separable at a preparative level.In the multi‐hyphenated approach used (hypernation), LC–NMR plays a key role since it provides the most detailed structural information. The relatively low sensitivity of this technique, however, requires that strategies for high loading of plant extracts are developed and compromises for solvent selection have to be made. For more demanding experiments, at‐line strategies based on the microfractionation of the LC‐peak of interest and recording of spectra in fully deuterated solvents in microflow probes represent a promising alternative. Copyright © 2005 John Wiley & Sons, Ltd.
Production of inbred and hybrid transgenic mice carrying large (> 200 kb) foreign DNA fragments by intracytoplasmic sperm injection
Authors: Osada Tomoharu , Toyoda Atsushi , Moisyadi Stefan , Akutsu Hidenori , Hattori Masahira , Sakaki Yoshiyuki , Yanagimachi Ryuzo 
Published: July 2005

AbstractWe have developed a mouse transgenesis technique that facilitates the insertion of large (∼200 kilo base pairs) DNA fragments into host genomes of both inbred and hybrid mice. Six inbred and three hybrid transgenic mice carrying a single bacterial artificial chromosome (BAC) clone with genes located in the Down syndrome critical region of human chromosome 21 were produced using this technology. Mol. Reprod. Dev. © 2005 Wiley‐Liss, Inc.
Comparison of voiding parameters in men and women with lower urinary tract symptoms
Authors: Ku Ja Hyeon , Oh Seung‐June 
Published: July 2005

AbstractAimThe aim of this study was to compare voiding parameters by using urodynamic investigations in men and women with lower urinary tract symptoms (LUTS).MethodsA total of 164 individuals (76 men and 88 women) completed the International Prostate Symptom Score (IPSS) and underwent a detailed urodynamic investigation. Patients were stratified by voiding function, which included bladder voiding efficiency (BVE) of < 80% and of ≥ 80%.ResultsIPSSs were similar in the men and women except for voiding symptoms for those with a BVE of ≥ 80% (12 for men vs. 9 for women, P = 0.016). When voiding parameters were compared according to BVE in men and women, respectively, maximum flow rate (Qmax) (P = 0.002), average flow rate (Qave) (P = 0.003), voided volume (P = 0.037), post‐void residual (PVR) (P < 0.001), and bladder outlet obstruction index (P = 0.016) were different for men with a BVE of < 80% and men with a BVE of ≥ 80%. However, for women with a BVE of < 80% or ≥ 80%, PVR (P < 0.001), detrusor pressure at maximum flow rate (P = 0.022), and opening detrusor pressure (P = 0.024) were different.ConclusionsThe voiding parameters of women differ from those of men according to voiding function. The present results show that a pressure‐flow study may represent a difference according to BVE in women as well as in men. Our findings suggest that opening detrusor pressure in women reflects the urethral and detrusor during voiding phase accurately as detrusor pressure at maximum flow rate does. Neurourol. Urodynam. © 2005 Wiley‐Liss, Inc.
Rubber composites reinforced by soy spent flakes
Authors: Jong L 
Published: July 2005

AbstractSoy spent flakes (SSF) is a plentiful renewable material from the waste stream of commercial soy protein extraction. SSF contains mostly soy carbohydrate and a small fraction of soy protein. Dry SSF is a rigid material and has a shear elastic modulus of ∼4 GPa. Aqueous dispersions of SSF were blended with styrene‐butadiene (SB) latex to form rubber composites. Soy carbohydrate increased the tensile stress in the small strain region, but also decreased the elongation at break. The shear elastic modulus of the composites showed an increase in the small strain region, consistent with the stress–strain behavior. The SSF composites showed a slightly better modulus recovery than the protein composite after eight cycles of strain sweep. In the small strain region, the shear elastic modulus of 30 % filled composites at 140 °C was about 160 times greater than that of the unfilled elastomer, showing a significant reinforcement effect caused by SSF. Compared with soy protein isolate, the recovery behavior after eight cycles of dynamic strain suggests that SSF composites have a slightly stronger filler–rubber interaction. In general, SSF composites gave a slightly higher composite strength compared with the protein composites, but at a much lower cost. Published in 2005 by John Wiley & Sons, Ltd.
Synthesis of zinc glutarates with various morphologies using an amphiphilic template and their catalytic activities in the copolymerization of carbon dioxide and propylene oxide
Authors: Kim Jong‐Seong , Kim Hyunchul , Yoon Jihwan , Heo Kyuyoung , Ree Moonhor 
Published: July 2005

AbstractVarious heterogeneous zinc glutarate (ZnGA) catalysts were synthesized in solvent systems of various polarities from zinc acetate dihydrate and glutaric acid with and without the aid of an amphiphilic block copolymer, poly(ethylene glycol‐b‐propylene glycol‐b‐ethylene glycol) (PE6400), as a template. The presence of the PE6400 template and the polarity of the solvent significantly affected the morphology, particle size, surface area, and crystallinity of the resulting catalyst. However, all the catalysts had the same crystal lattice unit cell structure and similar surface compositions. The surface compositions of the catalysts were quite different from those of conventionally prepared ZnGA catalysts, that is, those prepared from zinc oxide and glutaric acid in toluene. All these characteristics of the catalysts influenced the ZnGA‐catalyzed copolymerization of carbon dioxide and propylene oxide. The catalytic activities of the catalysts in this copolymerization depended primarily on their surface area and secondarily on their crystallinity; a larger surface area and a higher crystallinity resulted in higher catalytic activity. Of the catalysts that we prepared, the ZnGA catalyst that was prepared in ethanol containing 5.5 wt % water with the PE6400 template, ZnGA‐PE3, exhibited the highest catalytic activity in the copolymerization. The catalytic activity of ZnGA‐PE3 was attributed to its wrinkled petal bundle morphology, which provided a large surface area and high crystallinity. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4079–4088, 2005
Friction and wear mechanisms of polyamide 66/high density polyethylene blends
Authors: Chen Zhaobin , Li Tongsheng , Liu Xujun , Lü Renguo 
Published: July 2005

AbstractPolyamide 66 (PA66)/high density polyethylene (HDPE) blends having miscible structure were produced by compatibilization of HDPE grafted with maleic anhydride (HDPE‐g‐MAH). Mechanical and tribological properties of blends in different compositions were tested. It was found that the polymer blends greatly improved the mechanical properties of PA66 and HDPE. Blending HDPE with PA66 significantly decreased the friction coefficient of PA66; the friction coefficients of blends with different compositions were almost the same and approximately equal to that of pure HDPE; the blends with 80 vol % PA66 exhibited the best wear resistance. The transfer films, counterpart surfaces, and wear debris formed during sliding were investigated by Scanning Electron Microscopy (SEM), and Differential Scanning Calorimetry (DSC) analysis was further carried out on wear debris. These investigations indicated that the thermal control of friction model is applicable to PA66/HDPE blend, that is the friction coefficient of blend is governed by the HDPE component, which possesses a lower softening point relative to the PA66 component in this system. The wear mechanism of PA66/HDPE blend transforms from PA66 to HDPE as the HDPE content increases. PA66, as the component with higher softening point, increases the hardness of blend, enhances the ability of blend to form a transfer film on the counterface, and inhibits the formation of larger belt‐like debris of HDPE, at the same time, the presence of self‐lubricating HDPE in the system decreases the friction coefficient and the frictional heat, all of these factors are favorable for the wear resistance of PA66/HDPE blend. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2514–2523, 2005
Voltage dips at the terminals of wind power installations
Authors: Bollen Math H. J. , Olguin Gabriel , Martins Marcia 
Published: July 2005

AbstractThis article gives an overview of the kind of voltage dips that can be expected at the terminals of a wind power installation. The overview is based on the study of those dips at the terminals of industrial installations and provides a guideline for the testing of wind power installations against voltage dips. For voltage dips due to faults, a classification into different types is presented. Five types appear at the terminals of sensitive equipment and thus have to be included when testing the wind power installation against disturbances coming from the grid. A distinction is made between installations connected at transmission level and those connected at distribution level. For the latter the phase angle jump has to be considered. Dips due to other causes (motor, transformer and capacitor switching) are briefly discussed as well as the voltage recovery after a dip. Finally some thoughts are presented on the way in which voltage tolerance requirements should be part of the design process for wind power installations. Copyright © 2005 John Wiley & Sons, Ltd.
Large‐scale wind power farms as power plants
Authors: Gjengedal Terje 
Published: July 2005

AbstractThe integration of large‐scale wind power into weak power systems raises several issues that must be clarified. Typically these include the practical connection to the network, integration with the network system, system stability, system operation, necessary installations and extensions of the network, etc. At the same time, careful attention must be paid to the functional requirements such wind farms should meet in order to enhance system responses. Different wind power technologies have different characteristics and control possibilities. In this article, three technologies have been studied with respect to their dynamic performance, and a transient stability study has been performed in order to illustrate the differences in the three technologies. The results clearly show that there are differences in behaviour and in control possibilities. Hence there are also differences in how well they can meet functional requirements. When discussing to what degree strict requirements should be imposed on wind power, it should be kept in mind that some requirements can be met with small or moderate costs, while others may be expensive or difficult to meet. Some requirements may also mean a reduction in generation and hence in revenues. Rather than imposing strict requirements on wind turbines as such, ancillary services should be met in the most suitable way. It is not obvious that the same requirements should apply to wind power in hydro power‐dominated systems compared with, for instance, systems with a large share of nuclear or thermal power. It may well be cheaper to incorporate primary power control and system‐stabilizing equipment in other power plants or grid points than in many small wind turbine generators. General conclusions cannot be made on this, but the issue should be the focal point of system operators everywhere. Copyright © 2005 John Wiley & Sons, Ltd.
Stability of two superposed viscoelastic fluid‐particle mixtures
Authors: Kumar P. , Mohan H. , Singh G.J. 
Published: July 2005

AbstractThe stability of the plane interface separating two viscoelastic (Walters B′) superposed fluids of uniform densities in the presence of suspended particles is considered. The stability analysis has been carried out, for mathematical simplicity, for two highly viscoelastic fluids of equal kinematic viscosities and equal kinematic visco‐elasticities. For the (density wise) stable configuration, the system is found to be stable or unstable for the wave number range k ≤ or > \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$ {{1} \over {{\sqrt{2\nu \prime}}}} $\end{document} depending on the kinematic viscoelasticity ν′. However, the system is found to be unstable for the unstable configuration.
Phylogeography of the endangered tideland snail Batillaria zonalis in the Japanese and Ryukyu Islands
Authors: Kojima Shigeaki , Kamimura Satomi , Iijima Akiko , Kimura Taeko , Mori Keisuke , Hayashi Ikuo , Furota Toshio 
Published: July 2005

AbstractThe phylogeography of the endangered tideland snail Batillaria zonalis in the Japanese and Ryukyu Islands was analyzed on the basis of nucleotide sequences of a mitochondrial gene for cytochrome oxidase c subunit I (COI). Extremely low genetic diversity was found in populations at both the northern and southern boundaries of the geographic distribution of this species in Japan, i.e., Sendai Bay and Iriomotejima Island, respectively, which might be attributed to the population bottleneck due to historical environmental variations and/or the recent foundation of populations in the marginal part of the inhabitable range. Most populations contained unique rare haplotypes, and significant genetic differentiation on the whole was shown, while no clear geographic genetic structure was detected between the Japanese and Ryukyu Islands or over the distribution area of B. zonalis in Japan, with the exception of significant genetic divergences in Ago Bay in the central part of Honshu and the southern part of Okinawajima Island.
Of circles and spirals: Bridging the gap between the leading circle and spiral wave concepts of cardiac reentry
Authors: Comtois P. , Kneller J. , Nattel S. 
Published: July 2005

Abstract
The “leading circle model” was the first detailed attempt at understanding the mechanisms of functional reentry, and remains a widely-used notion in cardiac electrophysiology. The “spiral wave” concept was developed more recently as a result of modern theoretical analysis and is the basis for consideration of reentry mechanisms in present biophysical theory. The goal of this paper is to present these models in a way that is comprehensible to both the biophysical and electrophysiology communities, with the idea of helping clinical and experimental electrophysiologists to understand better the spiral wave concept and of helping biophysicists to understand why the leading circle concept is so attractive and widely used by electrophysiologists. To this end, the main properties of the leading circle and spiral wave models of reentry are presented. Their basic assumptions and determinants are discussed and the predictions of the two concepts with respect to pharmacological responses of arrhythmias are reviewed. A major difference between them lies in the predicted responses to Na+-channel blockade, for which the spiral wave paradigm appears more closely to correspond to the results of clinical and experimental observations. The basis of this difference is explored in the context of the fundamental properties of the models.
Englitazone administration to late pregnant rats produces delayed body growth and insulin resistance in their fetuses and neonates
Authors: Sevillano Julio , López-Pérez Inmaculada C. , Herrera Emilio , del Pilar Ramos María , Bocos Carlos 
Published: July 2005

The level of maternal circulating triacylglycerols during late pregnancy has been correlated with the mass of newborns. PPARγ (peroxisome-proliferator-activated receptor γ) ligands, such as TZDs (thiazolidinediones), have been shown to reduce triacylglycerolaemia and have also been implicated in the inhibition of tissue growth and the promotion of cell differentiation. Therefore TZDs might control cell proliferation during late fetal development and, by extension, body mass of pups. To investigate the response to EZ (englitazone), a TZD, on perinatal development, 0 or 50 mg of englitazone/kg of body mass was given as an oral dose to pregnant rats daily from day 16 of gestation until either day 20 for the study of their fetuses, or until day 21 of gestation for the study of neonates. EZ decreased maternal triacylglycerol levels at day 20 of gestation and neonatal mass, but not fetal mass. Fetuses and neonates from EZ-treated mothers exhibited high levels of insulin and were found to be hyperglycaemic. The apparent insulin-resistant state in neonates from EZ-treated pregnant rats was corroborated, since they showed higher plasma NEFA [non-esterified (‘free’) fatty acid] levels, ketonaemia and liver LPL (lipoprotein lipase) activity and lower plasma IGF-I (type 1 insulin-like growth factor) levels, in comparison with those from control mothers. Moreover, at the molecular level, an increase in Akt phosphorylation was found in the liver of neonates from EZ-treated mothers, which confirms that the insulin pathway was negatively affected. Thus the response of fetuses and neonates to maternal antidiabetic drug treatment is the opposite of what would be expected, and can be justified by the scarce amount of adipose tissue impeding a normal response to PPARγ ligands and by hyperinsulinaemia as being responsible for a major insulin-resistant condition.
Characterization of the Bacillus subtilis GTPase YloQ and its role in ribosome function
Authors: Campbell Tracey L. , Daigle Denis M. , Brown Eric D. 
Published: July 2005

We present an analysis of the cellular phenotype and biochemical activity of a conserved bacterial GTPase of unknown function (YloQ and YjeQ in Bacillus subtilis and Escherichia coli respectively) using a collection of antibiotics of diverse mechanisms and chemical classes. We created a yloQ deletion strain, which exhibited a slow growth phenotype and formed chains of filamentous cells. Additionally, we constructed a conditional mutant in yloQ, where growth was dependent on inducible expression from a complementing copy of the gene. In phenotypic studies, depletion of yloQ sensitized cells to antibiotics that bind at the peptide channel or peptidyl transferase centre, providing the first chemical genetic evidence linking this GTPase to ribosome function. Additional experiments using these small-molecule probes in vitro revealed that aminoglycoside antibiotics severely affected a previously characterized ribosome-associated GTPase activity of purified, recombinant YjeQ from E. coli. None of the antibiotics tested competed with YjeQ for binding to 30 or 70 S ribosomes. A closer examination of YloQ depletion revealed that the polyribosome profiles were altered and that decreased expression of YloQ led to the accumulation of ribosomal subunits at the expense of intact 70 S ribosomes. The present study provides the first evidence showing that YloQ/YjeQ may be involved in several areas of cellular metabolism, including cell division and ribosome function.