bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of aluminium coating on elemental signals in X‐ray microanalysis
Authors: Reid A. P. , Oates K. , Potts W. T. W. 
Published: February 2005

AbstractIt has been determined that, in the normal range of aluminium coating thicknesses used to remove charge from non‐conducting specimens in the electron microscope, no detectable influence on the elemental signals obtained in X‐ray microanalysis is observed. This is in contrast to a previous report (Hopkins et al., J. Electron Microsc. Tech., 18:176–182, 1991) of a reduction in elemental signal with increasing aluminium coating thickness. An explanation of errors in the previous interpretation is provided. © 1993 Wiley‐Liss, Inc.
Blood‐brain barrier permeability in rats is altered by exposure to magnetic fields associated with magnetic resonance imaging at 1.5 T
Authors: Prato Frank S. , Wills Jane M. , Roger J. , Frappier H. , Drost Dick J. , Lee Ting‐Yim , Shivers Richard R. , Zabel Pamela 
Published: February 2005

AbstractWe have previously reported that exposure of rats to low‐field (0.15 T) magnetic resonance imaging (MRI) increases blood‐brain barrier (BBB) permeability. However, a number of investigators have failed to observe this effect when high‐field MRI (1.5 T or higher) is used. Therefore, we investigated whether or not we would observe changes using our technique at these higher fields.Adult male Sprague‐Dawley rats were anaesthetised and then exposed to a 22.5 min imaging or sham procedure. Immediately following exposure, rats were injected with 1 MBq of 153Gd‐DTPA intracardially and then immediately re‐exposed for an additional 22.5 min. The rats were killed 1h following the second MRI exposure, at which time the brain was resected and 3ml of venous blood collected. The ratio of radioactivity per gram of brain to radioactivity per per milliliter of blood, known as the brain‐blood partition coefficient, was determined and used as a measure of BBB permeability. Groups of animals had different exposures. Group 1 (n = 9) was exposed to a clinically relevant MRI procedure. Group 2 (n = 20) was exposed to the same procedure except the rf specific absorption rate (SAR) was reduced to 25% and the animals were positioned 15 cm from imager centre to increase the time‐varying magnetic field from 0.4 to 2.8 T/s. For the sham exposures (n = 21), the animals were placed in the imager with the static field ramped down to zero and exposed to a sound recording simulating a MRI examination. In a third group (n = 11), exposure to only the static 1.5 T was investigated, while in a fourth group (n = 15), the exposure field was only to a static 1.89 T. Sham controls for groups 3 (n = 12) and 4 (n = 19) were silent.Group 1 showed an increase in BBB permeability (5.7 ± 0.5, mean ± SEM, P < 0.04, n = 9); however, group 2 showed a decrease (3.9 ± 0.2, P < 0.002, n = 20). Static field exposure of 1.5 T increased permeability (5.7 ± 0.5, P < 0.05, n = 11) as did 1.89 T (4.7 ± 0.4, P < 0.02, n = 15). Although there was no difference between sound and silent shams, shams done at night (4.8 ± 0.2, n = 32) were significantly greater (P < 0.0004) than those done during the day (3.7 ± 0.2, n = 19). Our results suggest changes in the rf and/or gradient field exposure can produce opposite effects on BBB permeability. Further, experiments involving only rf and only gradient field exposure are needed.The estimation of changes in BBB permeability by measuring the partition coefficient of compounds normally excluded by the BBB offers an objective quantitative technique which can detect changes of the order of 25%. This sensitivity is needed to explore the important, albeit subtle, effects of magnetic fields. © 1994 Wiley‐Liss, Inc.
Combination of cobalt labelling with immunocytochemical reactions for electron microscopic investigations on frog spinal cord
Authors: Nagy István , Sik Attila , Polgár Erika , Petkó Mihály , Antal Miklós 
Published: February 2005

AbstractCobalt staining of primary afferents in frog spinal cord was combined with peroxidase‐antiperoxidase pre‐embedding or immunogold post‐embedding immunocytochemical labelling. Our results have shown that cobalt labelling can easily be distinguished from both of the immunoreaction end products. The protocol of cobalt labelling did not affect the immunoreactivity of structures. The morphology and synaptology of cobalt labelled and immunostained profiles in our sections were very similar to those reported in previous studies using different double labelling techniques. These results indicate that this new combined method could be used as an alternative double labelling technique in electron microscopic studies on nervous tissues. © 1994 Wiley‐Liss, Inc.
Direct determination of five fluoroquinolones in chicken whole blood and in veterinary drugs by HPLC
Authors: Samanidou Victoria F. , Christodoulou Eleni A. , Papadoyannis Ioannis N. 
Published: February 2005

AbstractA direct, accurate, and sensitive chromatographic analytical method for the quantitative determination of five fluoroquinolones (enoxacin, ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin) in chicken whole blood is proposed in the present study. For quantitative determination lamotrigine was used as internal standard at a concentration of 20 ng/μL. The developed method was successfully applied to the determination of enrofloxacin, as the main component of commercially available veterinary drugs. Fluoroquinolone antibiotics were separated on an Inertsil (250×4 mm) C8, 5 μm, analytical column, at ambient temperature. The mobile phase consisted of a mixture of citric acid (0.4 mol L–1)–CH3OH–CH3CN (87 : 9 : 4% v/v) leading to retention times less than 14 min, at a flow rate 1.4 mL min–1. UV detection at 275 nm provided limits of detection of 2 ng/mL per 20 μL injected volume for enoxacin, norfloxacin, and ciprofloxacin, 0.4 ng/mL for ofloxacin, and 4 ng/mL for enrofloxacin. Preparation of chicken blood samples is based on the deproteinization with acetonitrile while the pharmaceutical drug was simply diluted with water. Peaks of examined analytes in real samples were identified by means of a photodiode array detector. The method was validated in terms of within‐day (n = 6) precision and accuracy after chicken whole blood sample deproteinization by CH3CN. Using 50 μL of chicken blood sample, recovery rates at fortification levels of 40, 60, and 80 ng ranged from 86.7% to 103.7%. The applicability of the method was evaluated using real samples from chicken under fluoroquinolone treatment.
Study of the Degradation of an Epoxy/Amine Resin, 2
Authors: Mailhot Bénédicte , Morlat‐Thérias Sandrine , Bussière Pierre‐Olivier , Gardette Jean‐Luc 
Published: February 2005

AbstractSummary: The degradation behaviour of a flexible epoxy/amine resin has been studied. The resin, made of DGEBA and polyether diamine (Jeffamine® D2000) has been submitted to photooxidation, photolysis (in absence of oxygen) and thermooxidation experiments. The nature and the mechanism of formation of the products have been previously reported in the first paper of this series. In this paper, the rate of formation of the degradation products and their distribution within the sample are discussed. The change in the rate of degradation observed after 30 h of irradiation in artificial ageing at λ > 300 nm in the presence of oxygen, measured by ATR‐FTIR and UV‐Vis spectrometries, is explained by a large attenuation of light intensity by the chromophoric photoproducts formed. The photooxidation profiles measured by micro‐FTIR showed a heterogeneous distribution of the photoproducts in the first 250 μm of the exposed surface. The formation of these photoproducts is associated to chain scission reactions. This was clearly evidenced by the decrease of stiffness measured by AFM nanoindentations in the same first 250 μm.Stiffness profiles measured by AFM nanoindentation of a photooxidised epoxy/amine sample.magnified imageStiffness profiles measured by AFM nanoindentation of a photooxidised epoxy/amine sample.
Study of the Degradation of an Epoxy/Amine Resin, 1
Authors: Mailhot Bénédicte , Morlat‐Thérias Sandrine , Ouahioune Mélanie , Gardette Jean‐Luc 
Published: February 2005

AbstractSummary: The degradation of an epoxy/amine resin was studied under photolytic conditions in absence and in presence of oxygen and under thermooxidative conditions. The resin is obtained after curing the diglycidyl ether of bisphenol‐A (DGEBA) with a poly(propylene glycol) which is diamine terminated. The mechanisms of degradation of the two separate components before curing were also investigated. Analysis by IR and UV‐Vis spectroscopies revealed that the oxidation photoproducts detected during the degradation of the epoxy/amine result from the oxidation of the DGEBA part, of the amine crosslinks and, to a lower extent, of the poly(oxypropylene) units. Their mechanism of formation essentially involves chain scission reactions. During irradiation, the yellowing observed is mainly due to the formation of a quinone methide structure. Thermooxidation generates high discoloration with some products only generated in that case. For all experiments, a detailed analysis of the IR spectra is given with the chemical mechanisms of formation of the degradation products.ATR‐IR spectra of an epoxy/amine sample in the carbonyl region during photooxidation.magnified imageATR‐IR spectra of an epoxy/amine sample in the carbonyl region during photooxidation.
Ultrarapid Molecular Release from Poly(N‐isopropylacrylamide) Hydrogels Perforated Using Silica Nanoparticle Networks
Authors: Kaneko Tatsuo , Asoh Taka‐aki , Akashi Mitsuru 
Published: February 2005

AbstractSummary: Porous poly(N‐isopropylacrylamide) (PNIPAAm) hydrogels were successfully prepared in the presence of nanosized silica particles with network morphology and subsequent silica extraction by HF treatment. The nanosized pores induced very rapid deswelling of the hydrogels, accompanied by volume phase transitions from swelling to deswelling states at approximately 30 °C. Deswelling, which was analyzed by a quick change in temperature of the aqueous media from 20 to 40 °C, was facilitated by increased silica particle content. The deswelling rate constant of the hydrogel prepared using silica nanoparticles with a network morphology (NT gel) was about 1 900‐fold greater than that of nonporous hydrogels and 13‐fold larger than that of porous hydrogels perforated using spherical silica nanoparticles (SP gel). The releasing rate of the low‐molecular weight chromophore from the NT gel was higher than that from the SP gel. In the chromophore‐labeled macromolecules, the network morphology was effective for increasing the releasing rate based on the transfer inside the hydrogel, as well as for increasing the amount released based on the surface pore morphology.
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Novel Thermosetting Resins Based on 4‐(N‐Maleimido)phenylglycidylether, 4
Authors: Liu Ying‐Ling , Wang Yao‐Hsuan , Chen Hsueh‐Shih 
Published: February 2005

AbstractSummary: A series of polymer‐clay nanocomposites were prepared by the simultaneous in situ curing of 4‐(N‐maleimido)phenylglycidylether/4,4‐diaminodiphenylmethane (MPGE/DDM) with the intercalation/exfoliation of various organo‐modified clays. The dispersion of the clays in the polymer matrix was produced by partial exfoliation and intercalation, as observed with X‐ray diffraction and transmission electronic microscopy. Clay modified with a carboxylic acid‐containing modifier showed enhancements with repesect to clay delamination in nanocomposite preparation. In comparison with the pristine resin, MPGE/DDM‐clay nanocomposites showed improved glass transition temperatures, thermal stability and flame retardance.Preparation and characterization of polymer‐clay nanocomposites based on a new maleimide‐epoxy hybrid monomer.magnified imagePreparation and characterization of polymer‐clay nanocomposites based on a new maleimide‐epoxy hybrid monomer.
IR Laser‐Induced Degradation of Poly(vinyl acetate): Novel Thermal Reactions in Solid Polymers
Authors: Kupčík Jaroslav , Blazevska‐Gilev Jadranka , Pola Josef 
Published: February 2005

AbstractSummary: Pulsed‐IR laser‐induced decomposition of poly(vinyl acetate) (PVAC) differs remarkably from its conventional pyrolysis, which results in the formation of acetic acid and non‐polar carbonaceous residue. In contrast, the products in the former case are (i) vinyl acetate (low energy channel), (ii) products of cleavage in the acetate group, and (iii) an ablatively deposited polar polymeric film containing roughly half of the acetoxy groups initially present.Schematic of the different routes of poly(vinyl acetate) degradation.magnified imageSchematic of the different routes of poly(vinyl acetate) degradation.
Anionic and cationic components from protein aggregates in bovine seminal plasma and their effects of sperm motility
Authors: Al‐Somai N. , C. Molan P. , Vishwanath R. , Shannon P. 
Published: February 2005

AbstractBovine seminal plasma proteins are in an aggregated form of high molecular weight in their native state. By immobilisation on a cation exchanger with exposure to disaggregating conditions (i.e., acetonitrile and low pH), the high‐molecular‐weight aggregates could be dissociated to slowly release the low‐molecular‐weight components. The anionic component released from the cation exchanger during disaggregation was collected by adsorption on a hydrophobic interaction column. The cationic component remaining on the cation exchanger was eluted with NaOH. Both components were found on gel permeation chromatography to be <5 kDa. SDS—PAGE of the various fractions showed that component of low molecular weight were still in an aggregated form.These components resulting from the disaggregation process have detrimental effects on sperm motility and the effects were more substantial compared with that of whole seminal plasma. All the cationic components were significantly detrimental to sperm motility, especially the fractions of low molecular weight. The anionic fractions reduced sperm motility when in an aggregated state. The isolated anionic peptide was not detrimental in its free form. In all fractions the peptides tended to re‐aggregate to a higher molecular weight under neutral conditions, however, the isolated anionic peptide (molecular weight <1,500) failed to do so. © Wiley‐Liss, Inc.
Activation of a Gi protein in digitonin/cholate‐solubilized membrane preparations of mouse sperm by the Zona pellucida, an egg‐specific extracellular matrix
Authors: Ning Xiaoping , Ward Cynthia R. , Kopef Gregory S. 
Published: February 2005

AbstractMammalian sperm possess guanine nucleotide‐binding regulatory proteins (G proteins) that are involved in signal transduction pathways leading to zona pellucida (ZP)‐mediated acrosomal exocytosis. We have previously examined ZP‐G protein dynamics in mouse sperm homogenates, as well as cell‐free membrane preparations, and our data support the existence of ZP receptor‐G protein complexes in sperm membranes. However, the composition of this complex has not been identified due to experimental limitations of the membrane preparations. In the present study, a detergent‐solubilized preparation from mouse sperm membranes that retained the signaling properties of cell homogenates and cell‐free membrane preparations was developed using buffers containing digitonin and cholate. GTPγS, a poorly hydrolyzable analogue of GTP, bound to these solubilized preparations in a specific and concentration‐dependent fashion that reached saturation at 100 nM. Incubation of this solubilized membrane preparation with heat‐solubilized ZP resulted in an increase in specific GTPγS binding in a concentration‐dependent manner, with a maximal response at 4‐6 ZP/μl. Mastoparan (50 μM) increased GTPγS binding to levels similar to that seen with solubilized ZP. Mastoparan plus ZP stimulated GTPγS binding to the same extent as mastoparan or ZP alone. Pertussis toxin completely inhibited ZP‐stimulated GTPγS binding and decreased mastoparan‐stimulated GTPγS binding by 50–60%. Purified ZP3, the ZP component that possesses quantitatively all of the sperm binding and acrosomal exocytosis‐inducing activities of the intact ZP, stimulated GTPγS binding to an extent similar to that of solubilized ZP. The properties of this solubilized membrane preparation are similar to those found in the cell homogenates and cell‐free membrane preparations, suggesting that the components involved in ZP3‐mediated signal transduction are effectively solubilized and are responsive to the ZP3 ligand. © 1995 Wiley‐Liss, Inc.
Bovine oviduct‐specific glycoprotein: A potent factor for maintenance of viability and motility of bovine spermatozoa in vitro
Authors: Abe Hiroyuki , Sendai Yutaka , Satoh Takeshi , Hoshi Hiroyoshi 
Published: February 2005

AbstractIn the cow, a specific glycoprotein‐bovine oviduct‐specific glycoprotein (BOGP)‐is secreted by the epithelial cells of the oviduct at the follicular stage of the estrous cycle. In this study, we examined the effects of purified BOGP on the viability and motility of bovine spermatozoa in culture in vitro. Frozen‐thawed bovine spermatozoa were incubated in modified Tyrode's solution (TALP) that contained purified BOGP (TALP‐BOGP). In TALP‐BOGP, both the viability and motility of bovine spermatozoa were more effectively maintained than in the control medium without any added protein. The increases in both the viability and motility of spermatozoa were dose‐dependent. Spermatozoa were also incubated in TALP medium supplemented with bovine serum albumin, egg albumin, lactalbumin, or gastric mucin, and their viability and motility in these media were compared with that in TALP‐BOGP. Both the viability and motility of spermatozoa were more effectively maintained in TALP‐BOGP throughout a 12‐hr incubation than in other media tested. An immunolabeling study demonstrated that a monoclonal antibody specific for BOGP reacted with the posterior region of the head, the middle portion, and the tail of spermatozoa that had been incubated with TALP‐BOGP, suggesting that BOGP becomes specifically associated with particular regions of the spermatozoon. These results suggest that BOGP is a potent factor for maintenance of the viability and motility of sperm. On the basis of the present results, we also propose that BOGP may play an important role in sperm functions during the reproductive process. © 1995 wiley‐Liss, Inc.
An engineering approach to dynamic prediction of network performance from application logs
Authors: Abusina Zalal Uddin Mohammad , Zabir Salahuddin Muhammad Salim , Ashir Ahmed , Chakraborty Debasish , Suganuma Takuo , Shiratori Norio 
Published: February 2005

AbstractNetwork measurement traces contain information regarding network behavior over the period of observation. Research carried out from different contexts shows predictions of network behavior can be made depending on network past history. Existing works on network performance prediction use a complicated stochastic modeling approach that extrapolates past data to yield a rough estimate of long‐term future network performance. However, prediction of network performance in the immediate future is still an unresolved problem. In this paper, we address network performance prediction as an engineering problem. The main contribution of this paper is to predict network performance dynamically for the immediate future. Our proposal also considers the practical implication of prediction. Therefore, instead of following the conventional approach to predict one single value, we predict a range within which network performance may lie. This range is bounded by our two newly proposed indices, namely, Optimistic Network Performance Index (ONPI) and Robust Network Performance Index (RNPI). Experiments carried out using one‐year‐long traffic traces between several pairs of real‐life networks validate the usefulness of our model. Copyright © 2005 John Wiley & Sons, Ltd.
A performance evaluation of BGP‐based traffic engineering
Authors: Quoitin Bruno , Pelsser Cristel , Bonaventure Olivier , Uhlig Steve 
Published: February 2005

AbstractMany Internet Service Providers tune the configuration of the Border Gateway Protocol on their routers to control their traffic. Content providers often need to control their outgoing traffic while access providers need to control their incoming traffic. We show, by means of measurements and simulations, that controlling the flow of the incoming interdomain traffic is a difficult problem. For this purpose, we first rely on detailed measurements to show the limitations of AS‐Path prepending. Then, we show by using large‐scale simulations that the difficulty of controlling the flow of the incoming traffic lies in the difficulty of predicting which BGP route will be selected by distant Autonomous Systems (ASs). Copyright © 2005 John Wiley & Sons, Ltd.
Synthesis and characterization of poly(L‐lactide‐co‐ε‐caprolactone) (B)‐poly(L‐lactide) (A) ABA block copolymers
Authors: Baimark Yodthong , Molloy Robert 
Published: February 2005

AbstractABA triblock copolymers of L‐lactide (LL) and ε‐caprolactone (CL), designated as PLL‐P(LL‐co‐CL)‐PLL, were synthesized via a two‐step ring‐opening polymerization in bulk using diethylene glycol and stannous octoate as the initiating system. In the first‐step reaction, an approximately 50:50 mol% P(LL‐co‐CL) random copolymer (prepolymer) was prepared as the middle (B) block. This was then chain extended in the second‐step reaction by terminal block polymerization with more L‐lactide. The percentage yields of the triblock copolymers were in excess of 95%. The prepolymers and triblock copolymers were characterized using a combination of dilute‐solution viscometry, gel permeation chromatography (GPC), 1H‐ and 13C‐NMR, and differential scanning calorimetry (DSC). It was found that the molecular weight of the prepolymer was controlled primarily by the diethylene glycol concentration. All of the triblock copolymers had molecular weights higher than their respective prepolymers. 13C‐NMR analysis confirmed that the prepolymers contained at least some random character and that the triblock copolymers consisted of additional terminal PLL end (A) blocks. From their DSC curves, the triblock copolymers were seen to be semi‐crystalline in morphology. Their glass transition, solid‐state crystallization, and melting temperature ranges, together with their heats of melting, all increased as the PLL end (A) block length increased. Copyright © 2005 John Wiley & Sons, Ltd.
Nanocomposites of poly[(butylene succinate)‐co‐(butylene adipate)] (PBSA) and twice‐functionalized organoclay
Authors: Chen Guangxin , Yoon Jin‐San 
Published: February 2005

AbstractA new method is described to prepare composites of poly[(butylene succinate)‐co‐(butylene adipate)] (PBSA) with an organophilic clay having a particular functional group, namely twice‐functionalized organoclay (TFC). TFCs were produced by treating Cloisite 25A® with (glycidyloxypropyl)trimethoxy silane (GPS) or (methacryloyloxypropyl)trimethoxy silane (MPS). Reaction of the silane compound with the organoclay surface was monitored by Fourier‐transform infrared spectroscopy (FTIR). PBSA composites with the three different clays were prepared successfully via melt mixing. The d spacing and the morphology of the composites were monitored by X‐ray diffraction and by transmission electron microscopy. The linear storage modulus of the composites in the melt state increased significantly as a result of incorporation of TFC. Tensile modulus and strength at break of PBSA/TFC–GPS and those of PBSA/TFC–MPS were far superior to those of PBSA/C25A. Copyright © 2005 Society of Chemical Industry