bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of polyurethaneurea–vinyl polymer (PUU–VP) uniform hybrid microspheres by SPG emulsification technique and subsequent suspension polymerization
Authors: Ma Guang‐Hui , An Chul‐Jun , Yuyama Hajime , Su Zhi‐Guo , Omi Shinzo 
Published: April 2003

AbstractUniform polyurethaneurea–vinyl polymer (PUU–VP) hybrid microspheres of about 20 μm were prepared by a Shirasu porous glass (SPG) membrane emulsification technique and a subsequent radical suspension polymerization process, that is, a mixture of a 40 wt % urethane prepolymer (UP) solution of xylene and a vinyl monomer (VP) containing an initiator was permeated through the uniform pores of the SPG membrane into a continuous phase containing a stabilizer to form uniform droplets. Then, the droplets were allowed to stand for chain extension at room temperature with di‐ or triamines for 2 h in the absence or presence of ethyl acetate (EA), followed by suspension polymerization at 70°C for 24 h. The effect of the type and the amount of the monomer composition, crosslinker, and chain extender on the monomer conversion, particle morphology, and stability of the dispersion was investigated. A strong relationship was found between the compatibility of PUU with VP and the stability of the dispersion. The monomer conversion increased and the stability of the dispersion was improved as the amount of the crosslinker was increased. Solid and spherical PUU–VA hybrid particles with a smooth surface and a higher destructive strength were obtained when a trifunctional crosslinker and a chain extender were used together. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 163–178, 2003
Phosphonylmethylaminocyclopentane‐1‐carboxylic acid
Authors: Najdenova E. , Vassilev A. , Popova Yu. , Troev K. 
Published: April 2003

AbstractPhosphonylmethylaminocyclopentane‐1‐carboxylic acid was synthesized using Kabachnik–Fields reaction conditions in high yield and was characterized by NMR (1H, 31P, and 13C) and FAB spectroscopy. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:229–230, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10124
Porosity‐dependent Young's modulus of membranes from polyetherether ketone
Authors: Sonnenschein Mark F. 
Published: April 2003

AbstractThe porosity‐dependent Young's modulus for PEEK membranes was determined and the data compared to several empirical and semiempirical equations often applied to porous systems. The Spriggs equation, Wang's approximation, Sudduth's equation, and the foam modulus‐density relationship were all tested against the data. The relatively wide range of porosities tested in these experiments shows the Spriggs equation to be inadequate to fitting the data, especially above 50% porosity where the Young's modulus decreases rapidly. Wang's approximation to second order fitted the data well, and the porosity‐modulus relations had non‐negative coefficients as required and consistent with the ceramic data obtained by others. The data also fitted Sudduth's equations, usually applied to sintered ceramics, but equivalently good fits were obtained with nonunique fitting parameters. The foam modulus‐density relationship fitted the data for foamlike membranes but fitted less well to nonfoam morphology membranes. Finally, the data were used to determine the range of porosities and hollow fiber dimensions necessary for microfiltration and composite membrane application. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1168–1174, 2003
Investigation of the micromechanical deformation behavior of styrene–butadiene star block copolymer/polystyrene blends with high‐voltage electron microscopy
Authors: Ivankova E. M. , Adhikari R. , Michler G. H. , Weidisch R. , Knoll K. 
Published: April 2003

AbstractThe deformation behavior of blends consisting of a styrene–butadiene star block copolymer and a polystyrene homopolymer was studied by high‐voltage electron microscopy with a tensile device. The mechanical properties and micromechanical deformation mechanisms in the star block copolymer/polystyrene blends were directly influenced by their morphology. Although the pure block copolymer deformed in a very unequal manner (because of a thin‐layer‐yielding mechanism) and revealed no local deformation zones, a transition to the formation of crazelike zones was observed in the blends. This transition in the deformation mechanisms was correlated to the abrupt change in the macroscopic strain at break of the injection‐molded specimens. At lower contents of added polystyrene, a craze‐stopping mechanism was observed, whereas the blends with higher polystyrene contents demonstrated crazing like that in pure polystyrene. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1157–1167, 2003
Multiphoton entanglement and interferometry
Authors: Bourennane M. , Eibl M. , Gaertner S. , Kiesel N. , Kurtsiefer C. , Żukowski M. , Weinfurter H. 
Published: April 2003

AbstractMultiphoton entanglement is the basis of many quantum communication schemes, quantum cryptographic protocols, and fundamental tests of quantum theory. Spontaneous parametric down‐conversion is the most effective source for polarization entangled photon pairs. Here we show, that a class of entangled 4‐photon states can be directly created by parametric down‐conversion. These states exhibit perfect quantum correlations and a high robustness of entanglement against photon loss. Therefore these states are well suited for new types of quantum communication.
Entanglement properties of Gaussian states
Authors: Kraus B. , Giedke G. , Lewenstein M. , Cirac J.I. 
Published: April 2003

AbstractOn the one hand we present necessary and sufficient conditions for both the separability and the distillability of bipartite Gaussian states of an arbitrary number of modes. On the other hand we classify tripartite three‐mode Gaussian states according to their separability properties and provide necessary and sufficient conditions for separability of those states . All the conditions presented here can be easily checked by direct calculations, thus providing operational criteria. This solves the separability problem for all bipartite as well as tripartite three‐mode Gaussian states and the distillability problem for all bipartite Gaussian states.
Active teleportation and entanglement swapping of a vacuum‐one photon qubit
Authors: Sciarrino F. , Lombardi E. , Giacomini S. , De Martini F. 
Published: April 2003

AbstractWe report the experimental realization of the “active” quantum teleportation (QST) of a one‐particle entangled qubit. The qubit is physically implemented by a two‐dimensional subspace of states of a mode of the electromagnetic field, specifically, the space spanned by the vacuum and the one photon state. This demonstration completes the original QST protocol and renders it available for actual implementation in quantum computation networks. It is accomplished by implementing a 8 m optical delay line and a single‐photon triggered fast Electro‐Optic Pockels cell. A large value of teleportation “fidelity” was attained: Fa = 90 ∓ 2)%. Furthermore we present a scheme for delayed‐entanglement swapping by applying the same quantum optical method.
Quantum gates and Berry phases in Josephson nanostructures
Authors: Falci G. , Fazio R. , Palma G.M. 
Published: April 2003

AbstractWe will show how geometric phases, i.e. phases which appear when a system undergoes a cyclic adiabatic evolution, can find useful application in fault tolerant quantum computation. A particular setup based on coupled superconducting nanostructures will be described
Entanglement at distance: qubits versus continuous variables
Authors: D'Ariano G.M. , Sacchi M.F. 
Published: April 2003

AbstractWe consider the problem of obtaining maximally entangled photon states at distance in the presence of loss. We compare the efficiency of two different schemes in establishing N shared ebits: i) N single ebit states with the qubit encoded on polarization; ii) a single continuous variable entangled state (emode) assisted by optimal local operation and classical communication (LOCC) protocol in order to obtain a 2N‐dimensional maximally entangled state, with qubits encoded on the photon number.
Bringing quantum strangeness to the macroscopic world
Authors: Mancini S. , Vitali D. , Tombesi P. , Giovannetti V. 
Published: April 2003

AbstractWe show that bouncing laser beams can entangle massive oscillators like movable mirrors. Such entanglement results robust against thermal noise and detectable with common optomechanical apparatus. Thus, a quantum strangeness (entanglement) can be brought to the macroscopic, everyday, world.
Glutathione S‐transferases and malondialdehyde in the liver of NOD mice on short‐term treatment with plant mixture extract P‐9801091
Authors: Petlevski R. , Hadžija M. , Slijepčević M. , Juretić D. , Petrik J. 
Published: April 2003

AbstractChanges in the concentration of glutathione S‐transferases (GSTs) and malondialdehyde (MDA) were assessed in the liver of normal and diabetic NOD mice with and without treatment with the plant extract P‐9801091. The plant extract P‐9801091 is an antihyperglycaemic preparation containing Myrtilli folium (Vaccinium myrtillus L.), Taraxaci radix (Taraxacum ofﬁcinale Web.), Cichorii radix (Cichorium intybus L.), Juniperi fructus (Juniperus communis L.) , Centaurii herba (Centaurium umbellatum Gilib.), Phaseoli pericarpium (Phaseolus vulgaris L.), Millefolii herba (Achillea millefolium L.), Mori folium (Morus nigra L.), Valerianae radix (Valeriana ofﬁcinalis L.) and Urticae herba et radix (Urtica dioica L). Hyperglycaemia in diabetes mellitus is responsible for the development of oxidative stress (via glucose auto‐oxidation and protein glycation), which is characterized by increased lipid peroxide production (MDA is a lipid peroxidation end product) and/or decreased antioxidative defence (GST in the liver is predominantly an α enzyme, which has antioxidative activity). The catalytic concentration of GSTs in the liver was signiﬁcantly reduced in diabetic NOD mice compared with normal NOD mice (p < 0.01), while the concentration of MDA showed a rising tendency (not signiﬁcant). The results showed that statistically signiﬁcant changes in antioxidative defence occurred in the experimental model of short‐term diabetes mellitus. A 7‐day treatment with P‐9801091 plant extract at a dose of 20 mg/kg body mass led to a signiﬁcant increase in the catalytic concentration of GSTs in the liver of diabetic NOD mice (p < 0.01) and a decrease in MDA concentration (not signiﬁcant), which could be explained by its antihyperglycaemic effect. Copyright © 2003 John Wiley & Sons, Ltd.
Male rat infertility induction/spermatozoa and epididymal plasma abnormalities after oral administration of Kalanchoe gastonis bonnieri natural juice
Authors: de la Luz Miranda‐Beltrán María , Puebla‐Pérez Ana María , Guzmán‐Sánchez Arnoldo , Huacuja Ruiz Luis 
Published: April 2003

AbstractNatural aqueous crude extracts (NACE) of several Crassulaceae family plants have been applied as a vaginal contraceptive by the populace. The aim of this work was to evaluate the inhibition of fertility in male Wistar rats and some physiological and biochemical changes in spermatozoa and epididymal plasma induced by NACE from Kalanchoe gastonis bonnieri (K. g. b.) (Crassulaceae). The NACE was obtained by mechanic pressure on grinding fresh plant leaves. Sublethal doses (150–300 mg/kg body weight) of NACE were orally administered to adult and fertile male rats daily for 30 days in a search for a contraceptive effect, and physiological and biochemical modiﬁcations on sperm cells and cauda epididymal plasma. The toxicity studies revealed that the lethal dose (LD50) calculated was 11 g/kg body weight. Sublethal doses induced 50%–100% fertility inhibition, with 100% recovery of fertility 30 days after stopping the treatment. The sperm motility, viability and spermatic density were also signiﬁcantly decreased (p < 0.001). The outstanding biochemical change observed in the cauda epididymal plasma was a decrease of carnitine concentration. The NACE of K. gastonis contains one substance active on fertility by affecting spermatozoa motility, viability and sperm density with a signiﬁcantly decreased carnitine and sialic acid (p < 0.001) in the caudal epididymal plasma. Copyright © 2003 John Wiley & Sons, Ltd.
Antioxidant flavonoids and phenolic acids from leaves of Leea guineense G. Don (Leeaceae)
Authors: Op de Beck Philippe , Cartier Gilbert , David Bruno , Dijoux‐Franca Marie‐Geneviève , Mariotte Anne‐Marie 
Published: April 2003

AbstractFrom leaves of Leea guineense (Leeaceae) three hydrophilic ﬂavonoids were isolated and identiﬁed as quercetin‐3′‐sulphate‐3‐O‐α‐L‐rhamnopyranoside, quercetin‐3,3′‐disulphate and a new ﬂavonoid sulphate, quercetin‐3,3′,4′‐trisulphate, together with kaempferol, quercetin, quercitrin, mearnsitrin, gallic acid and ethyl gallate. The structures were established by spectroscopic analysis (UV, MS, 1H‐NMR, 13C‐NMR and 2D‐NMR). Their antioxidant effect on free radical scavenging was evaluated in the DPPH assay. Copyright © 2003 John Wiley & Sons, Ltd.
Cerebrosides and their fatty acid profile in different regions of brains from small‐for‐date infants
Authors: Rao P. Srinivasa 
Published: April 2003

AbstractThe concentration of cerebrosides and their fatty acid profile were determined in different regions of the brain, namely cerebrum, cerebellum and medulla oblongata, of normal infants (weighing > 2500 g) and of the two categories of small‐for‐date term infants (weighing 2000–2500 g and < 2000 g). Cerebroside concentration, in general, was observed to be low in the three regions of the brain from small‐for‐date infants. The magnitude of reduction varied with the region. The cerebrum, in particular, showed a significant reduction in the concentration of cerebrosides in the case of low‐birth‐weight infants. The nonhydroxy fatty acid distribution of cerebrosides indicated a lower proportion of long‐chain fatty acids, namely lignoceric (24:0) and nervonic (24:1) acids, in the cerebellum and the medulla oblongata of small‐for‐date infants, and also in the cerebrum of those weighing < 2000 g. The observed changes in the concentration of cerebrosides and their fatty acid profile point to the possibility of impaired myelinization of the brain in small‐for‐date infants.
Response of neuropeptides and neurotransmitter binding sites in the retina and brain of the developing chick to reduced visual input
Authors: Ali S.F. , Hong J.‐S. , Bondy S.C. 
Published: April 2003

AbstractThe effect of 17 days of monocular suture of eyelids of day‐old chicks upon levels of neuropeptides and high affinity binding sites was studied. A significant reduction of met‐enkephalin, but not of substance P or neurotensin, was observed in the retina of the eye receiving dim and unpatterned light. Retinal muscarinic, dopaminergic, opiate, and benzodiazepine receptors appeared unaltered by the experimental procedure. Levels of neuropeptides were not significantly changed in optic lobes contralateral to and innervated by the sutured eyes relative to the optic lobes receiving afferentation from the open eyes. Seventeen days after unilateral enucleation of new‐hatched chicks, the neuropeptide content of the smaller denervated optic lobes did not differ from that of the lobes receiving an intact neuronal input.
Polyamine acetylation in the developing and aging mouse brain
Authors: Ortiz José G. , Giacobini Ezio , Schmidt‐Glenewinkel Thomas 
Published: April 2003

AbstractPutrescine and spermidine acetylation is at least 10‐fold higher in the brain homogenate of the neonate (1‐day‐old) mouse than in the adult (90 days old). Although the pattern of putrescine and spermidine acetylation is similar throughout development, the acetylation of spermidine is consistently higher. As the animal matures, the activity curves tend to converge.In the P1 (crude nuclei) and microsomal fractions, the acetylation of spermidine is highest at day 1, while putrescine acetylation peaks at day 4. In contrast to the adult animal, putrescine and spermidine acetylation are present in the P2 (crude mitochondria) and soluble fractions. In the P2 fraction, spermidine acetylation is highest at birth, while the acetylation of putrescine peaks at day 3. Acetylation of both substrates is barely detectable by day 42. In the soluble fraction, putrescine and spermidine acetylation show the highest activity at day 5. The activity declined towards adult values by day 10 in all the fractions examined.Acetylation of putrescine and spermidine is approximately 4‐fold higher in the brain homogenate of the 120‐day‐old mouse than in that of the 90‐day‐old mouse. Both the acetylation of putrescine and spermidine decline as the animal grows older. In contrast to the perinatal period (day 20 of gestation to 4 days old) the acetylation of putrescine is almost identical to that of spermidine in the adult mouse.These results suggest that polyamine acetylation may play an important role in polyamine metabolism in the developing mouse brain. The presence of activity in the P2 and soluble fractions of the neonatal, but not adult mouse brain, suggests that putrescine, via acetylputrescine, may contribute to the GABA levels during development.
Protein synthesis in cells isolated from the developing rat cerebellum
Authors: Patel N.J. , Cohen J. , Balazs R. 
Published: April 2003

AbstractThe rate of protein synthesis was estimated in structurally preserved perikaryal preparations from 8‐day‐old rat cerebellum under conditions which overcome the problems of intracellular compartmentation. The rates were lower than the in vivo estimates at comparable ages, but they were of similar magnitude, and very much higher than previous estimates on isolated cells.Protein synthesis rate depended on the cell type. When expressed per cell the rank order in the preparations enriched in the indicated classes of cells was: Purkinje cells > astrocytes > granule cells in the S, G2 and M phase of the cell cycle > granule cells in G1 and G0. However, after normalizing the results for size differences between cell types, by expressing the rates in terms of unit protein or as a percentage replacement of the protein bound amino acid, astrocytes and replicating granule cells displayed greater rates than the Purkinje cells.The resolution of labelled proteins using SDS‐PAGE indicated marked differences in the rate of synthesis of particular proteins. The results were consistent with the view that certain polypeptides are uniquely expressed in particular cell classes.
Existence of [3H]serotonin binding sites in the rat spinal cord: A developmental study
Authors: Hernandez R.J. , Fong D. Martinez , Chagoya G. , Fillion M.P. , Fillion G. 
Published: April 2003

Abstract[3H]5‐HT specific binding sites have been characterized in the rat spinal cord. Experimental conditions allowed us to study a single class of sites possibly related to the postsynaptic receptor for 5‐HT. Binding constants (KD and Bmax) are described for adult and developing animals. No substantial changes in affinity were observed but the number of receptors increased from birth up to day 20 postnatally, stabilizing thereafter. The developmental pattern of a presynaptic marker, tryptophan‐5‐hydroxylase, was similar to that of binding sites.
First appearance of laminin in peripheral nerve, cerebral blood vessels and skeletal muscle of the rat embryo
Authors: Bignami Amico , Chi Nguyen Huu , Dahl Doris 
Published: April 2003

AbstractThe formation of basal laminae in peripheral nerve was studied by immunofluorescence with laminin antisera in the rat embryo. Peripheral nerves were identified with neurofilament antisera in double labeled sections. In the adult rat perineurium and endoneurium were uniformly decorated by the antisera. Sensory neurons in posterior root ganglia were surrounded by a laminin positive basal lamina. Laminin immunoreactivity was first observed in posterior spinal roots on day 14. Anterior spinal roots and peripheral nerves remained laminin negative until day 17. The adult pattern (uniform decoration of endoneurium in large and small nerve trunks) was only observed on day 21. The formation of a basal lamina surrounding posterior root ganglion neurons was still not completed in 3‐day‐old rats. The only laminin positive structures in the brain and spinal cord were the external basal laminae and the blood vessels. The external basal lamina was present at all stages of development. In the spinal cord and brain stem vascular basal laminae were first identified with laminin antisera on day 14, in the diencephalon and telencephalon on day 15. Laminin immunoreactivity in the basal laminae surrounding myotubes was first observed on day 16.
Nicotinic acetylcholine receptor from foetal human skeletal muscle
Authors: Turnbull Gillian M. , Harrison Roger , Lunt George G. 
Published: April 2003

AbstractNicotinic acetylcholine receptor protein has been purified from foetal and adult skeletal muscle by extraction in non‐ionic detergent followed by purification on immobilised α‐toxin. Purified foetal and adult receptors focused as single, sharp peaks whether directly labelled with 125I or indirectly labelled with 125I‐α‐bungarotoxin. Polyacrylamide gel electrophoresis of the purified foetal and adult receptors each showed four major protein bands with Mr 44,000, 51,000, 58,000 and 66,000; only that with Mr 44,000 was, in each case, labelled with the affinity reagent, 4‐(N‐maleimido) [3H]benzyltrimethylammonium. When the four major subunits, obtained by polyacrylamide gel electrophoresis, were labelled with 125I‐ConA, markedly different patterns of radioactivity were shown by the foetal and adult receptors, the band at 44,000 being less heavily labelled in the foetal case. Foetal and adult receptors behaved similarly with respect to inhibition by ConA of binding of 125I‐α‐bungarotoxin; inhibition in both cases reaching a maximum of 70%. Foetal and adult receptors each showed single 125I‐α‐bungarotoxin binding species in sucrose density gradient centrifugation with S20w = 8.5Sand 9.5S, respectively, although the former peak was broader, possibly reflecting the relative instability of the purified foetal receptor. Our finding of marked differences in the glycosylation of foetal and adult human acetylcholine receptors suggest that, in otherwise very similar proteins, the carbohydrate moieties could determine the known differences in location and stability of the two receptor types.
Ganglioside GM1 overcomes serum inhibition of neuritic outgrowth
Authors: Skaper Stephen D. , Varon Silvio 
Published: April 2003

AbstractConsiderable variations in both neuritic and non‐neuronal cell outgrowths of ganglionic expiant cultures are imposed when different substrata and medium supplements are used. Therefore, a neuritic response to exogenous agents such as gangliosides may be better, or exclusively revealed under selected combinations of medium and substratum. We have surveyed a number of different ganglia for their ability to display a neuritic response to ganglioside GM1 and the culture conditions under which such a display may take place. GM1 can recognizably promote neurite extension from embryonic day 8 chick dorsal root ganglia, day 11 sympathetic ganglia, and day 8 ciliary ganglia. Demonstration of such effects, however, requires an appropriate balance between promoting and inhibiting influences by other extrinsic influences (culture substrata, neuronotrophic factors, serum inhibitors) thereby allowing for improvement by the ganglioside. Different ganglia require different combinations of those influences. Ciliary ganglia, for example, will show a GM1 response on a polyornithine substratum in medium supplemented with the chick eye Ciliary Neuronotrophic Factor and 1% fetal calf serum, but not with 10% serum or no serum. The effective concentration range for GM1 is in accord with previously reported serum binding data. These, and other data are consistent with an action of GM1 in executing a neurite program, rather than an imposition of the program itself.