bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microtubule assembly after treatment of pig oocytes with taxol: Correlation with chromosomes, γ‐tubulin, and MAP kinase*
Authors: Sun Qing‐Yuan , Lai Liangxue , Wu Guang‐Ming , Park Kwang‐Wook , Day Billy N. , Prather Randall S. , Schatten Heide 
Published: August 2002

AbstractIn this study, taxol was used as a tool to study the correlation of microtubule assembly with chromosomes, γ‐tubulin and phosphorylated mitogen‐activated protein (MAP) kinase in pig oocytes at different maturational stages. Taxol treatment did not affect meiotic resumption and chromosome condensation but inhibited/disrupted chromosome alignment at the metaphase plate and bipolar spindle formation and thus meiotic progression. Microtubules were co‐localized with chromosomes and were found to emanate from the chromosomes in taxol‐treated oocytes, suggesting that chromosomes may serve as a source of microtubule organization. In addition, the concentric emanation of microtubules within the chromosome‐surrounded area in taxol‐treated oocytes suggests that microtubule emanation from the chromosomes may be directed by other microtubule‐organizing material. The formation of one large spindle or ≥2 spindles in oocytes after taxol removal shows that minus end microtubule‐organizing material can be normally located on both sides of chromosomes only when the chromosomes are aligned on the metaphase plate. The co‐localization of γ‐tubulin and phosphorylated MAP kinase with microtubule assembly in both control and taxol‐treated oocytes suggests that these two proteins are associated microtubule‐nucleating material in pig oocytes. However, Western blot analysis showed that neither cytoplasmic microtubule aster formation nor extensive microtubule assembly in the chromosome region induced by taxol was caused by super‐activation of MAP kinase. Taxol also induced microtubule assembly depending on chromosome distribution in the first polar body. The results suggest that chromosomes are always co‐localized with microtubules and that emanation of microtubules from the chromosomes may be regulated/directed by microtubule‐organizing material including γ‐tubulin and phosphorylated MAP kinase in pig oocytes. Mol. Reprod. Dev. 60: 481–490, 2001. © 2001 Wiley‐Liss, Inc.
Regeneration of peripheral nerves after clenbuterol treatment in a rat model
Authors: Frerichs Onno , Fansa Hisham , Ziems Pieter , Schneider Wolfgang , Keilhoff Gerburg 
Published: August 2002

AbstractClenbuterol is known to act as a neuroprotective substance in the central nervous system, and also reduces muscle atrophy after denervation. The aim of this study was to evaluate its influence on peripheral nerve regeneration. The rat sciatic nerve model was used in four groups (n = 8 per group). After complete nerve transection and microsurgical coaptation, two groups received a daily oral dose of 100 μg/kg clenbuterol and two served as controls. Regeneration was assessed clinically, histologically, and morphometrically after 4 and 6 weeks. The weight ratios of calf muscles were calculated. Histological examination showed significantly increased axon counts in the clenbuterol group and a better degree of myelination. Muscle weight ratios of the clenbuterol group were significantly increased after 6 weeks, and the animals showed improved function of the hindlimb. Thus, therapy with 100 μg/kg clenbuterol daily after coaptation of a sciatic nerve showed a positive influence on clinical, histological, and morphometrical parameters in the rat model. The underlying mechanism remains unclear. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1687–1691, 2001
Focal cooling improves neuronal conduction in peroneal neuropathy at the fibular neck
Authors: Rutkove Seward B. 
Published: August 2002

AbstractHeat can induce conduction block (CB) in demyelinated neurons; whether cooling can reverse CB and increase strength is uncertain. In six patients with electrophysiologic evidence of peroneal neuropathy at the fibular neck with definite motor CB, standard motor nerve conduction studies were performed at 32°C and then after the fibular neck region was cooled with an ice pack to 8°–12°C. In all patients, cooling increased the amplitude and area of the compound motor action potential obtained with popliteal fossa stimulation, decreasing the relative amplitude drop across the fibular neck from a mean of 78% to 55%. A concomitant increase in foot dorsiflexor strength was clearly observed in three of the six patients. Both the electrophysiologic and clinical changes readily reversed upon rewarming. These data support the belief that, in compressive neuropathies, cooling relieves conduction block in selected motor neurons, improving strength. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1622–1626, 2001
Computer simulation of jitter phenomenon in neuromuscular transmission disorders
Authors: Miralles Francesc 
Published: August 2002

AbstractNeuromuscular jitter is a sensitive measure of the safety factor of neuromuscular transmission. Nevertheless, the actual relationship between jitter and the safety factor is unknown because these parameters have not been simultaneously measured. In order to explore the theoretical relationship between them, a computer model of mammalian neuromuscular transmission has been developed. If the safety factor is expressed as the absolute value of the natural logarithm of the probability of a block, the model predicts a double exponential relationship between the safety factor and jitter, except when the percentage of blocks is greater than 90%. In that case, the jitter value decreases. Simulation of acetylcholinesterase inhibition shows that this treatment decreases the neuromuscular transmission blocks more effectively in postsynaptic than in presynaptic disorders. In contrast, when the percentage of blocks is greater than 60%, the jitter value increases in both conditions. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1635–1646, 2001
A new approach to detect the contact of two‐dimensional elliptical particles
Authors: Džiugys Algis , Peters Bernhard 
Published: August 2002

AbstractThe objective of this paper is to introduce a new algorithm to calculate analytically the overlap of two‐dimensional ellipses. The algorithm may be applied for the direct numerical simulation of granular material dynamics by the discrete element method (DEM). The stability of the algorithm is analysed. Moreover, optimization for possible iterative methods is dealt with. Copyright © 2001 John Wiley & Sons, Ltd.
A new enzymic method for the isolation and culture of human bladder body smooth muscle cells
Authors: Ma F.‐H. , Higashira H. , Ukai Y. , Hanai T. , Kiwamoto H. , Park Y.C. , Kurita T. 
Published: August 2002

AbstractCultured cells of the human urinary bladder smooth muscle are useful for investigating bladder function, but methods for culturing them are not well developed. We have now established a novel enzymic technique. The smooth muscle layer was separated out and incubated with 0.2% trypsin for 30 min at 37°C. The samples were then minced and incubated with 0.1% collagenase for 30 min and centrifuged at 900 g. The pellets were resuspended in RPMI‐1640 medium containing 10% fetal calf serum (FCS) and centrifuged at 250 g. The smooth muscle cells from the supernatant were cultured in RPMI‐1640 containing 10% FCS. The cells grew to confluence after 7–10 days, forming the “hills and valleys” growth pattern characteristic of smooth muscle cells. Immunostaining with anti‐α‐actin, anti‐myosin, and anti‐caldesmon antibodies demonstrated that 99% of the cells were smooth muscle cells. To investigate the pharmacological properties of the cultured cells, we determined the inhibitory effect of muscarinic receptor antagonists on the binding of [3H]N‐methylscopolamine to membranes from cultured cells. The pKi values obtained for six antagonists agreed with the corresponding values for transfected cells expressing the human muscarinic M2 subtype. Furthermore, carbachol produced an increase in the concentration of cytoplasmic free Ca2+ an action that was blocked by 4‐diphenylacetoxy‐N‐methylpiperidine methiodide, an M3 selective antagonist. This result suggests that these cells express functional M3 muscarinic receptors, in addition to M2 receptors. The subcultured cells therefore appear to be unaffected by our new isolation method. Neurourol. Urodynam. 21:71–79, 2002. © 2002 Wiley‐Liss, Inc.
Rare‐event component importance for the consecutive‐k system
Authors: Chang Hsun‐Wen , Hwang F.K. 
Published: August 2002

AbstractVarious indices of component importance with respect to system reliability have been proposed. The most popular one is the Birnbaum importance. In particular, a special case called uniform Birnbaum importance in which all components have the same reliability p has been widely studied for the consecutive‐k system. Since it is not easy to compare uniform Birnbaum importance, the literature has looked into the case p = ½, p → 1, or p ≥ ½. In this paper, we look into the case p → 0 to complete the spectrum of examining Birnbaum importance over the whole range of p. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 159–166, 2002; DOI 10.1002/nav.10001
Detection of a Markovian target with optimization of the search efforts under generalized linear constraints
Authors: Dambreville Frédéric , Le Cadre Jean‐Pierre 
Published: August 2002

AbstractThis paper deals with search for a target following a Markovian movement or a conditionally deterministic motion. The problem is to allocate the search efforts, when search resources renew with generalized linear constraints. The model obtained is extended to resource mixing management. New optimality equations of de Guenin's style are obtained. Practically, the problem is solved by using an algorithm derived from the FAB method. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 117–142, 2002; DOI 10.1002/nav.10009
Antennal SNMPs (sensory neuron membrane proteins) of lepidoptera define a unique family of invertebrate CD36‐like proteins
Authors: Rogers Matthew E. , Krieger Jürgen , Vogt Richard G. 
Published: August 2002

AbstractSNMP1‐Apol is an antennal‐specific protein of the wild silk moth Antheraea polyphemus; the protein is abundantly expressed and localized to the receptor membranes of sex‐pheromone specific olfactory sensory neurons (OSNs). SNMP1‐Apol is thought to function in odor detection based on its olfactory‐specific expression, localization within OSNs, developmental time of expression, and apparent homology to the CD36 family of membrane‐bound receptor proteins. In the current study, SNMP1‐Apol homologues were identified from the moths Bombyx mori, Heliothis virescens, and Manduca sexta. These species posses antennal mRNAs encoding proteins with amino acid sequence identities ranging from 75–80%; these proteins are collectively designated SNMP1. A second M. sexta SNMP homologue, previously identified and partially sequenced [Robertson et al.: Insect Mol Biol 8:501–518, 1999] was fully sequenced and characterized. The encoded protein shares only 26–27% sequence identity with the SNMP1 proteins, and is thus designated SNMP2‐Msex. The SNMP sequences were used to identify 14 and four possible homologues in Drosophila melanogaster and Caenorhabditis elegans genome databases, respectively; thus, greatly expanding CD36 family membership among the invertebrate lineages. Despite their sequence difference, SNMP1‐Msex and SNMP2‐Msex expression is localized to OSNs and occurs simultaneously with the onset of olfactory function. These findings suggest that SNMPs play a central role in odor detection in insects, and that the CD36 gene family is widely represented among animal phyla. The SNMPs are the only identified neuronal members of the CD36 family, and as such expand the activities of this gene family into roles influencing brain function and behavioral action. © 2001 John Wiley & Sons, Inc. J Neurobiol 49: 47–61, 2001
Synthesis of methyl methacrylate oligomers with substituted tetraphenylethane initiator
Authors: Roussel J , Boutevin B 
Published: August 2002

AbstractThe radical polymerization of (meth)acrylic monomers (eg methyl methacrylate; MMA) with benzopinacolate‐type initiators has been investigated mainly by Bledzki and Braun. With respect to this work, the typical system (MMA/1,1,2,2‐tetraphenyl‐1,2‐bis(trimethylsiloxy)ethane) has been investigated.The concomitant uses of 1H NMR and size exclusion chromatography have allowed the percentage of MMA telechelic oligomers present in the medium versus reaction time to be followed. The results show clearly a decrease in the living character of this type of radical polymerization with evolution from telechelic oligomers to monofunctional polymers. In addition, the polymerization features versus reaction time are simulated using the GEAR package; good agreement between the calculated and experimental data is obtained.© 2001 Society of Chemical Industry
Mechanical characteristics of modified unsaturated polyester resins derived from poly(ethylene terephthalate) waste
Authors: Farahat Medhat S 
Published: August 2002

AbstractThe depolymerization of poly(ethylene terephthalate) (PET), by an alcoholysis reaction is an easy operation and gives prospects for the utilization of wastes. PET waste was first depolymerized by glycolysis reaction at three different molar ratios of diethylene glycol (DEG), in the presence of manganese acetate as a transesterification catalyst. Copolyesters of PET modified with varied mole ratios of p‐hydroxybenzoic acid (PHBA) were reported to exhibit excellent mechanical and chemical properties due to their liquid crystalline behaviour. Here we study the effect of incorporating (PHBA) units into the building structures of different unsaturated polyesters synthesized originally from glycolysed PET waste. Modified unsaturated polyesters were synthesized by depolymerizing PET with DEG, and the obtained oligoesters were reacted with PHBA and maleic anhydride (MA). The molar ratio of the added PHBA was varied to investigate its effect on the mechanical characteristics of these modified unsaturated polyesters. The data obtained reveal that increasing the molar ratio of PHBA within the studied range of concentrations leads to a pronounced improvement in the mechanical characteristics, which is represented mainly by the values of/maximum compression strength (σmax) and Young's modulus (EY).© 2002 Society of Chemical Industry
Theoretical studies on heats of formation for polynitrocubanes using the density functional theory B3LYP method and semiempirical MO methods
Authors: Zhang Ji , Xiao Heming , Gong Xuedong 
Published: August 2002

AbstractThe heats of formation (HOFs) have been calculated for 21 polynitrocubane compounds using semiempirical MO methods (MINDO/3, MNDO, AM1 and PM3) and for eight of 21 polynitrocubanes containing one to four nitro groups using the density functional theory method at the B3LYP/6‐31G* level by means of designed isodesmic reactions. The cubane cage skeletons in the polynitrocubane molecules have been kept in setting up the isodesmic reactions to produce more accurate and reliable results. It is found that there is a good linear relationship between the HOFs of eight polynitrocubanes calculated using the B3LYP/6‐31G* and PM3 methods, but not for the other methods, and the linear correlation coefficient equals 0.9971. Subsequently, accurate HOFs at the B3LYP/6‐31G* level of the other 13 polynitrocubanes containing four to eight nitro groups were obtained by systematically correcting their PM3‐calculated HOFs. All 21 polynitrocubane compounds have high HOFs, implying that they can be very powerful energetic materials. The relationship between the HOFs and molecular structures for polynitrocubanes is discussed. Copyright © 2001 John Wiley & Sons, Ltd.
From well‐defined diblock copolymers prepared by a versatile atom transfer radical polymerization method to supramolecular assemblies
Authors: Ranger Maxime , Jones Marie‐Christine , Yessine Marie‐Andrée , Leroux Jean‐Christophe 
Published: August 2002

AbstractThe synthesis of well‐defined diblock copolymers by atom transfer radical polymerization (ATRP) was explored in detail for the development of new colloidal carriers. The ATRP technique allowed the preparation of diblock copolymers of poly(ethylene glycol) (PEG) (number‐average molecular weight: 2000) and ionic or nonionizable hydrophobic segments. Using monofunctionalized PEG macroinitiator, ionizable and hydrophobic monomers were polymerized to obtain the diblock copolymers. This polymerization method provided good control over molecular weights and molecular weight distributions, with monomer conversions as high as 98%. Moreover, the copolymerization of hydrophobic and ionizable monomers using the PEG macroinitiator made it possible to modulate the physicochemical properties of the resulting polymers in solution. Depending on the length and nature of the hydrophobic segment, the nonionic copolymers could self‐assemble in water into nanoparticles or polymeric micelles. For example, the copolymers having a short hydrophobic block (5 < degree of polymerization < 9) formed polymeric micelles in aqueous solution, with an apparent critical association concentration between 2 and 20 mg/L. The interchain association of PEG‐based polymethacrylic acid derivatives was found to be pH‐dependent and occurred at low pH. The amphiphilic and nonionic copolymers could be suitable for the solubilization and delivery of water‐insoluble drugs, whereas the ionic diblock copolymers offer promising characteristics for the delivery of electrostatically charged compounds (e.g., DNA) through the formation of polyion complex micelles. Thus, ATRP represents a promising technique for the design of new multiblock copolymers in drug delivery. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3861–3874, 2001
Vinyl polymerization with a binary system of p‐chlorobenzenediazonium salt and sodium tetraphenylborate
Authors: Sato Tsuneyuki , Takahashi Toru , Seno Makiko , Hirano Tomohiro 
Published: August 2002

AbstractA combined system of sodium tetraphenylborate (STPB) and p‐chlorobenzenediazonium tetrafluoroborate (CDF) serves as an effective initiator at low temperatures for acrylate monomers such as methyl methacrylate (MMA), ethyl acrylate, and di‐2‐ethylhexyl itaconate. The polymerization of MMA with the STPB/CDF system has been kinetically investigated in acetone. The polymerization shows a low overall activation energy of 60.3 kJ/mol. The polymerization rate (Rp) at 40 °C is given by Rp = k[STPB/CDF]0.5[MMA]1.6, when the molar ratio of STPB to CDF is kept constant at unity, suggesting that STPB and CDF form a complex with a large stability constant and play an important role in initiation and that MMA participates in the initiation process. From the results of a spin trapping study, p‐chlorophenyl and phenyl radicals are presumed to be generated in the polymerization system. A plausible initiation mechanism is proposed on the basis of kinetic and electron spin resonance results. A large solvent effect on the polymerization can be observed. The largest Rp value in dimethyl sulfoxide is 11 times the smallest value in N,N‐dimethylformamide. The copolymerization of MMA and styrene with the STPB/CDF system gives results somewhat different from those of conventional radical copolymerization. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4206–4213, 2001
Molecular structure determination of Ni(II) diimine complex and DMA analysis of Ni(II) diimine‐based polyethenes
Authors: Liimatta J. O. , Löfgren B. , Miettinen M. , Ahlgren M. , Haukka M. , Pakkanen T. T. 
Published: August 2002

AbstractDynamic mechanical thermoanalysis showed that polyethene, prepared under suitable polymerization conditions with the Brookhart‐type catalyst dibromo‐N,N′‐1,2‐acenaphthylenediylidenebis[2,6‐bis(1‐methylethyl)benzeneamine]Ni(II)/methylaluminoxane (MAO), behaved like an elastomer, even though no comonomer was added. A structural characterization showed that the polymers contained methyl to hexyl branches and some longer branches. The effect of the polymerization conditions on branching was investigated through variations in the pressure and temperature of the polymerization. Depending on the degree and type of branching, polyethene was either quite amorphous or highly crystalline with a high melting temperature. The solid‐state structure of the catalyst dibromo‐N,N′‐1,2‐acenaphthylenediylidenebis[2,6‐bis(1‐methylethyl)benzeneamine]Ni(II) consisted of two centrosymmetrically related monomeric moieties, where Ni atoms were bridged by two bromide ligands. The Ni atom was five‐coordinated, with a square pyramidal coordination polyhedron. The sixth coordination site of the octahedral geometry was effectively blocked by the isopropyl groups of the 2,6‐C6H3(i‐Pr) substituents of the diimine ligand. In solution in the presence of MAO, the longer bridging NiBr bonds broke, and the complex dissociated to a monomeric species. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1426–1434, 2001
Synthesis of polyphenylquinoxaline copolymers via aromatic nucleophilic substitution reactions of an A‐B quinoxaline monomer
Authors: Klein Daniel J. , Korleski Joseph E. , Harris Frank W. 
Published: August 2002

AbstractA self‐polymerizable quinoxaline monomer (A‐B) has been synthesized and polymerized via aromatic nucleophilic substitution reactions. An isomeric mixture of self‐polymerizable quinoxaline monomers—2‐(4‐hydroxyphenyl)‐3‐phenyl‐6‐fluoroquinoxaline and 3‐(4‐hydroxyphenyl)‐2‐phenyl‐6‐fluoroquinoxaline—was polymerized in N‐methyl‐2‐pyrrolidinone (NMP) to afford high molecular weight polyphenylquinoxaline (PPQ) with intrinsic viscosities up to 1.91 dL/g and a glass‐transition temperature (Tg) of 251 °C. A series of comonomers was polymerized with A‐B to form PPQ/polysulfone (PS), PPQ/polyetherether ketone (PEEK), and PPQ/polyethersulfone (PES) copolymers. The copolymers readily obtained high intrinsic viscosities when fluorine was displaced in NMP under reflux. However, single‐electron transfer (SET) side reactions, which limit molecular weight, played a more dominant role when chlorine was displaced instead of fluorine. SET side reactions were minimized in the synthesis of PPQ/PS copolymers through mild polymerization conditions in NMP for longer polymerization times. Thus, the Tg's of PES (Tg = 220 °C), PEEK (Tg = 145 °C), and PS (Tg = 195 °C) were raised through the incorporation of quinoxaline units into the polymer. Copolymers with high intrinsic viscosities resulted in all cases, except in the case of PPQ/PEEK copolymers when 4,4′‐dichlorobenzophenone was the comonomer. © 2001 John Wiley & Sons, Inc. J Polym Sci A Part A: Polym Chem 39: 2037–2042, 2001
Star‐polymer synthesis via radical reversible addition–fragmentation chain‐transfer polymerization
Authors: Stenzel‐Rosenbaum Martina , Davis Thomas P. , Chen Vicki , Fane Anthony G. 
Published: August 2002

AbstractPolystyrene stars were synthesized by reversible addition–fragmentation chain‐transfer (RAFT) polymerization using hexakis(thiobenzoylthiomethyl)benzene (I) as a hexafunctional RAFT agent at 80, 100, and 120 °C. The polymerizations conformed to pseudo‐first‐order kinetic behavior. The molecular weight distributions displayed characteristics consistent with a living radical process. A number of salient features were observed in the molecular weight distributions with the star distribution accompanied by a linear polymer‐chain distribution and shoulders on the distributions that can be attributed to radical–radical‐termination events. The evidence suggests that high temperatures are required to activate all the RAFT active sites on I, and a hypothesis proposes that there is significant steric hindrance in the initial stages of the RAFT process with I. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2777–2783, 2001