bluuebunny/crossref_metadata_2025_split huggingface dataset:
Age‐related expression of σ1 receptors and antidepressant efficacy of a selective agonist in the senescence‐accelerated (SAM) mouse
Authors: Phan Vân‐Ly , Miyamoto Yoshiaki , Nabeshima Toshitaka , Maurice Tangui 
Published: January 2005

AbstractThe σ1 receptor is a unique intracellular receptor whose activation results in an efficient modulation of several neurotransmitter responses. Its role as a target for the rapid nongenomic effects of neuro(active)steroids and the age‐related diminutions in steroid levels suggested that targeting the σ1 receptor might allow alleviation of age‐related neuronal dysfunctions. We examined here the expression and behavioral efficacy of σ1 receptors in the senescence‐accelerated (SAM) mouse model. The σ1 receptor mRNA expression was measured by using comparative RT‐PCR in the olfactory bulb, hippocampus, hypothalamus, cortex, or cerebellum of senescence‐prone SAMP/8 and senescence‐resistant SAMR/1 control animals. No difference was observed between substrains in 6‐, 9‐, and 12‐month‐old (m.o.) mice. The σ1 protein expression was analyzed by using immunohistochemical techniques. Labeling was intense in the olfactory bulb, hippocampus, hypothalamus, and midbrain of both SAMR/1 and SAMP/8 mice, and the distribution appeared unchanged in 6‐, 9‐, and 12‐m.o. animals. The receptor's in vivo availability was examined by using in vivo [3H](+)‐SKF‐10,047 binding. No age‐related difference was observed in the olfactory bulb, hippocampus, hypothalamus, cortex, cerebellum, and brainstem of 6‐ or 12‐m.o. SAMR/1 or SAMP/8 mice. The antidepressant efficacy of the selective agonist igmesine was examined in the forced‐swimming test. The compound decreased significantly the immobility duration at 60 mg/kg in 6‐ and 12‐m.o. SAMR/1 and in 6‐m.o. SAMP/8 mice. In 12‐m.o. SAMP/8 mice, the drug efficacy was facilitated; a significant effect was measured at 30 mg/kg. Decreased neurosteroid levels, particularly of progesterone, were seen in 12‐m.o. SAMP/8 mice that might explain the enhanced efficacy of igmesine. Preserved σ1 receptor expression and enhanced behavioral efficacy of σ1 agonists were measured in SAM animals, confirming the therapeutic opportunies for selective ligands against age‐related mood disorders. © 2005 Wiley‐Liss, Inc.
Stereoblock Poly(lactic acid): Synthesis via Solid‐State Polycondensation of a Stereocomplexed Mixture of Poly(L‐lactic acid) and Poly(D‐lactic acid)
Authors: Fukushima Kazuki , Furuhashi Yukiko , Sogo Kazuaki , Miura Shigenobu , Kimura Yoshiharu 
Published: January 2005

AbstractSummary: Stereoblock poly(lactic acid) consisting of D‐ and L‐lactate stereosequences can be successfully synthesized by solid‐state polycondensation of a 1:1 mixture of poly(L‐lactic acid) and poly(D‐lactic acid). In the first step, melt‐polycondensation of L‐ and D‐lactic acids is conducted to synthesize poly(L‐lactic acid) and poly(D‐lactic acid) with a medium‐molecular‐weight, respectively. In the next step, these poly(L‐lactic acid) and poly(D‐lactic acid) are melt‐blended in 1:1 ratio to allow formation of their stereocomplex. In the last step, this melt‐blend is subjected to solid‐state polycondensation at temperature where the dehydrative condensation is allowed to promote chain extension in the amorphous phase with the stereocomplex crystals preserved. Finally, stereoblock poly(lactic acid) having high‐molecular‐weight is obtained. The stereoblock poly(lactic acid) synthesized by this way shows a higher melting temperature in consequence of the controlled block lengths and the resulting higher‐molecular‐weight. The product characterization as well as the optimization of the polymerization conditions is described.Changes in $\overline M _{\rm w}$ of stereoblock poly(lactic acid) (sb‐PLA) as a function of the reaction time.imageChanges in $\overline M _{\rm w}$ of stereoblock poly(lactic acid) (sb‐PLA) as a function of the reaction time.
Comb‐Like Ionic Complexes of Cationic Surfactants with Bacterial Poly(γ‐glutamic acid) of Racemic Composition
Authors: García‐Alvarez Monserrat , Alvarez José , Alla Abdelilah , Martínez de Ilarduya Antxon , Herranz Concepción , Muñoz‐Guerra Sebastián 
Published: January 2005

AbstractSummary: Comb‐like ionic complexes, nATMA · PG(DL)GA, were prepared from microbial poly(γ‐glutamic acid), with a nearly racemic configuration, and alkyltrimethylammoniun bromides, with linear alkyl chains containing an even number of carbon atoms, n, ranging from 12 to 22. The complexes had a nearly stoichiometric composition, displayed thermal stability up to temperatures above 200 °C and were insoluble in water but soluble in organic solvents. In the solid state, they were arranged in a regularly layered structure with the alkyl side chain crystallized for n ≥ 18. Heating above melting entailed a contraction in the interlayer distance which varied from 1 to 10% depending on the value of n. Comparison with data reported on similar complexes obtained from nearly enantiomerically pure poly(γ‐glutamic acid) revealed an overall behavior very similar for the two series but with specific significant differences concerning side chain crystallinity and dimensional response to temperature.image
Cover Picture: Macromol. Mater. Eng. 12/2004
Authors: Sharma Lakshmi , Ogino Yoshino , Kanaya Toshiji 
Published: January 2005

Cover: For the first time, a shish kebab structure has been discovered in PHB, using a series of in‐situ rheo SAXS and DPLS methods. This finding changes the fundamentals of this unique biopolymer and creates a ‘new’ PHB macromolecule possessing a range of previously unforeseen chemical and physical properties.Further details can be found in the Full Paper by L. Sharma,* Y. Ogino, and T. Kanaya on page 1059.
Cover Picture: Macromol. Rapid Commun. 1/2005
Authors: Vyazovkin Sergey , Dranca Ion , Lang Anthony J. 
Published: January 2005

Cover: The application of an oscillating tensile load to a nitrocellulose film causes its degradation as detected by mass spectrometry (MS). An isothermal dynamic mechanical analysis (DMA)‐MS run is shown. This combination of DMA with MS provides a new approach to detecting mechanochemical degradation under moderate strain fields.Further details can be found in the Communication by S. Vyazovkin,* I. Dranca, and A. J. Lang on page 29.
Interface Orientation and Chain Conformation in Simulated Symmetric Diblock Copolymer Lamellar Systems
Authors: Yang Jian , Winnik Mitchell A. , Pakula Tadeusz 
Published: January 2005

AbstractSummary: We describe the results of Monte Carlo simulations, based on the cooperative motion algorithm, of the lamellar structure generated at finite temperature by a symmetric diblock copolymer. The (70 × 70 × 70) simulation box in which the polymer chains were embedded for each simulation was rotated, based on the interface orientation, to bring the interfacial planes of the simulated structure into parallel. We found that the interface thickness, as defined by the distribution of the junction points, became narrower at lower temperature, and that the interface plane was characterized by a waviness with a maximum peak‐to‐valley distance of 20–30 lattice bonds. Compared with the isotropic state (T/N = ∞), chains at lower temperatures were stretched in the direction perpendicular to the interface; but only modestly compressed in the direction parallel to the interface. Individual block chains within the lamellar domains still behave like random coils. The block copolymer molecules exhibit only a modest tendency to orient themselves with their end‐to‐end vector perpendicular to the plane of the lamellar interface. Considered as an ensemble average, the results we obtained are similar to those reported from small angle neutron scattering measurements for the mean conformation of the PSd blocks of symmetrical PSd‐PVP diblock copolymers.2‐D projections onto the X‐Z plane of the end beads for the A‐ and B‐chains (gray) and the junction points J (black) at T/N = 0.2. The interface plane is oriented parallel to the Y‐Z plane by rotating the simulation box. The distribution profiles of junction points and the end beads across the system in the direction of interface normal are shown in the lower part of the figure.image2‐D projections onto the X‐Z plane of the end beads for the A‐ and B‐chains (gray) and the junction points J (black) at T/N = 0.2. The interface plane is oriented parallel to the Y‐Z plane by rotating the simulation box. The distribution profiles of junction points and the end beads across the system in the direction of interface normal are shown in the lower part of the figure.
Properties of stationary states of delay equations with large delay and applications to laser dynamics
Authors: Yanchuk Serhiy 
Published: January 2005

AbstractWe consider properties of periodic solutions of the differential‐delay system, which models a laser with optical feedback. In particular, we describe a set of multipliers for these solutions in the limit of large delay. As a preliminary result, we obtain conditions for stability of an equilibrium of a generic differential‐delay system with fixed large delay τ. We also show a connection between characteristic roots of the equilibrium and multipliers of the mapping obtained via the formal limit τ→∞. Copyright © 2004 John Wiley & Sons, Ltd.
Short‐segment nerve conduction studies in ulnar neuropathy at the elbow
Authors: Visser Leo H. , Beekman Roy , Franssen Hessel 
Published: January 2005

AbstractThe aim of the study was to assess the diagnostic value of short‐segment nerve conduction studies (NCS) at 2‐cm intervals from 4 cm above to 4 cm below the medial epicondyle in a large group of patients with ulnar neuropathy at the elbow (UNE). Furthermore, we wanted to compare electrodiagnostic and clinical findings. We evaluated 73 arms in 70 patients with UNE and observed the following abnormalities on short‐segment NCS: focal conduction block (CB) in 1, focal CB with increased latency change in 34, and increased latency change alone in 25. Short‐segment NCS had an additional localizing value in 28 arms of the 37 patients (76%) with motor conduction velocity (MCV) slowing across the elbow only or with nonlocalizing electrodiagnostic findings. The lesion was located above the elbow in 32 arms (53%), at the epicondyle in 16 arms (27%), and below the epicondyle in 12 (20%) of the 60 arms with focal CB or increased latency change on short‐segment NCS. Patients with CB on routine and short‐segment NCS had muscle weakness significantly more often than patients without CB. Thus, short‐segment NCS are useful in localizing the lesion in patients with UNE and CB on routine NCS and have additional diagnostic value in patients with MCV slowing across the elbow or with nonlocalizing signs on routine nerve conduction studies. We recommend its use in all patients in whom UNE is suspected. Muscle Nerve, 2005
Oxygen infusions (hemoglobin‐vesicles and albumin‐hemes) based on nano‐molecular sciences
Authors: Tsuchida Eishun , Sakai Hiromi , Komatsu Teruyuki , Takeoka Shinji , Huang Yubin , Sou Keitaro , Nakagawa Akito , Teramura Yuji , Kobayashi Koichi 
Published: January 2005

AbstractSince the discovery of a red‐colored saline solution of a heme derivative that reversibly binds and releases oxygen (1983), significant efforts have been made to realize an oxygen infusion as a red cell substitute based on the sciences of both molecular assembling phenomena and macromolecular metal complexes. The authors have specified that hemoglobin (Hb)‐vesicles (HbV) and recombinant human serum albumin‐hemes (rHSA‐heme) would be the best systems that meet the clinical requirements. (A) Hb is rigorously purified from outdated, donated red cells via pasteurization and ultrafiltration, to completely remove blood type antigen and pathogen. The HbV encapsulates thus purified concentrated Hb solution with a phospholipid bimolecular membrane (diameter, 250 nmϕ), and its solution properties can be adjusted comparable with blood. Surface modification of HbV with a water‐soluble polymer ensures stable dispersion state and storage over a year at 20°C. In vivo tests have clarified the efficacy for extreme hemodilution and resuscitation from hemorrhagic shock, and safety in terms of biodistribution, metabolism in reticuloendothelial system (RES), clinical chemistry, blood coagulation, etc. The HbV does not induce vasoconstriction thus maintains blood flow and tissue oxygenation. (B) rHSA is now manufactured in Japan as a plasma‐expander. The rHSA can incorporate eight heme derivatives (axial base substituted hemes) as oxygen binding sites, and the resulting rHSA‐heme is a totally synthetic O2‐carrier. Hb binds endothelium‐derived relaxation factor, NO, and induces vasoconstriction. The rHSA‐heme binds NO as Hb does, however, it does not induce vasoconstriction due to its low pI (4.8) and the resulting low permeability across the vascular wall (1/100 of Hb). A 5%‐albumin solution possesses a physiologic oncotic pressure. Therefore, to increase the O2‐transporting capacity, albumin dimer is effective. Albumin dimer can incorporate totally 16 hemes with a regulated oncotic pressure. The rHSA‐heme is effective not only as a red cell substitute but also for oxygen therapeutics (e.g. oxygenation for tumor). Significant efforts have been made to produce HbV and rHSA‐heme with a facility of Good Manufacturing Practice (GMP) standard, and to start preclinical and finally clinical trials. Copyright © 2005 John Wiley & Sons, Ltd.
Transient shear rheology and rheo‐optical microstructural characterization of a thermotropic liquid crystalline polymer
Authors: Guo Tianren , Harrison Graham M. , Ogale Amod A. 
Published: January 2005

AbstractThe shear rheology and the corresponding microstructure evolution during transient flow of a thermotropic liquid crystalline polymer (LCP; Vectran V400P) are reported; the polymer does not display a crystalline melting phenomenon. The steady shear viscosity displays three regions that are typical of LCPs. However, the transient shear stress displays a local stress maximum at a strain of ≈ 2, a local minimum at a strain of ≈ 20, and then a stress overshoot at a strain of ≈ 100 before attaining a steady state value. The transient first normal stress difference exhibits a distinct overshoot at ≈ 100 strain units. The steady‐state first normal stress difference is always positive in the tested shear rate range 0.1–10 s–1. In situ rheo‐optical characterization revealed that the melt shows a threaded texture at rest. Upon start up of shear flow, this threaded texture becomes deformed, and the domains initially appear to stretch and align in the shearing direction. Next, the domains break up, and a significant drop in the optical intensity is observed. These microstructural features are used to explain the presence of the first maximum and the minimum observed in the transient shear stress. Polym. Eng. Sci. 45:187–197, 2005. © 2005 Society of Plastics Engineers.
Theoretical model for flash generation
Authors: Higuchi Hiroyuki , Kosaka Wataru , Koyama Kiyohito 
Published: January 2005

AbstractReduction of flash generated in a gas vent is of great concern for manufacturers of electronic parts. The present study proposes a theoretical model for flash generation through consideration of flow characteristics in a gas vent. The model predicts the factors controlling flash, i.e., material parameters such as zero‐shear viscosity, crystallization temperature, thermal conductivity, and heat capacity, and process parameters such as injection and mold wall temperatures, packing pressure, and the clearance of a gas vent. On the other hand, we measure the amount of flash generated in the molding of poly(phenylene sulfide) (PPS) composites containing glass fiber and spherical fillers (CaCO3 or Al2O3). Flash reduces with decreasing size of spherical fillers. These experimental data are successfully interpreted using the flash model. Polym. Eng. Sci., 45:198–206, 2005. © 2005 Society of Plastics Engineers
Structural characterization and mass transfer properties of segmented polyurethane: influence of block length of hydrophilic segments
Authors: Hu Jin‐Lian , Mondal Subrata 
Published: January 2005

AbstractAn attempt has been made to investigate the effect of the block length of hydrophilic segments on the structure and mass transfer properties of segmented polyurethane (HSPU). Three different block lengths of hydrophilic poly(ethylene glycol) (PEG) segments were used, namely PEG‐200, PEG‐2000 and PEG‐3400, where the numbers indicate the molecular weight of the PEG in g mol−1. The HSPU were characterized using Fourier‐transform infrared (FTIR) spectroscopy, wide‐angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and tensile testing. Mass transfer properties were measured by sorption and water vapour flux (WVF) measurements. The control sample polyurethanes without PEG and a sample with PEG‐200 showed amorphous structure and an unclear phase separation as detected by WAXD, DSC and DMTA. There is evidence that the introduction of PEG blocks into the polyurethane matrix aids soft‐segment crystallization. The percentage crystallinity of soft segments was the highest with PEG‐2000 and an increase of PEG block length to 3400 g mol−1 resulted in a decrease in crystallinity. Mechanically, polyurethane without PEG is tough while percentage strain at maximum load increased with increasing block length of PEG. In addition, sorption and WVF increased linearly with increasing PEG block length and with temperature. The permeability of such HSPUs is a function of temperature and showed a good fit to an Arrhenius form. Copyright © 2005 Society of Chemical Industry
Marcus‐grunwald theory and the nitroalkane anomaly
Authors: Albery W. John , Bernasconi Claude F. , Kresge A. Jerry 
Published: January 2005

AbstractThe Disparity reaction proposed in a recent application of Marcus‐Grunwald theory to nitroalkane ionization is shown to put the reaction's transition state in an energy‐diagram region where electronic rearrangement leads proton transfer, contrary to experimental evidence; it is suggested that addition of solvent reorganization to electronic rearrangement as the second reaction progress variable would remedy this situation.
Reaction of triethylsilyl radical with sulfides, a laser flash photolysis study
Authors: Soundararajan N. , Jackson James E. , Platz Matthew S. 
Published: January 2005

AbstractTriethylsilyl radical was generated by laser flash photolysis of a 1:1 (v/v) solution of triethylsilane and di‐tert‐butyl peroxide. The silicon centered radical was reacted with sulfides to give carbon centered radicals by displacement at sulfur. The carbon radicals were readily detected by their transient absorption spectra. The absolute rate of reaction of triethylsilyl radical with 9‐fluorenylphenylsulfide, di‐n‐butylsulfide, di‐sec‐butyl sulfide, di‐tert‐butyl sulfide and di‐n‐butyl disulfide are 2.40 ± 0.12 × 108 M−1S−1, 1.1 × 107±0.89×106M−1S−1, 8.79± 0.73×106M−1S−1, 3.29±0.18×106 M−1S−1, and 3.41±0.09×108 M−1S−1, respectively.
Reaction of sulfur ylides with elemental sulfur and selenium. Aspects and mechanistic considerations
Authors: Nakayama Juzo , Akimoto Keiichi , Hoshino Masamatsu 
Published: January 2005

AbstractThe reaction of sulfur ylides with elemental sulfur or selenium initially affords thio‐ or seleno‐carbonyl compounds, which then react with starting ylides to give episulfides or episelenides from which the heteroatom (sulfur or selenium) is extruded to give olefins as the final product. In the case of carbonyl‐stabilized ylides, the resulting thio‐ or seleno‐carbonyl compounds react with starting ylides to afford 1,3‐oxathioles or 1,3‐oxaselenoles as previously reported. Supporting evidence for the intermediacy of thio(seleno)‐carbonyl compounds and episulfides (episelenides) is presented.
Non‐planar structures of the pentafluoroallyl and 1,1‐difluoroallyl anions
Authors: Dixon David A. , Fukunaga Tadamichi , Smart Bruce E. 
Published: January 2005

AbstractThe structures of the allyl anion (1) and two fluoro‐substituted derivatives, perfluoro (2) and 1,1‐difluoro (3) have been calculated by ab inito molecular orbital theory. Geometries were gradient optimized, and force fields and an MP‐2 correlation correction were determined at stationary points. The calculations were done with a double zeta basis set augmented by d functions on carbon (DZ + Dc). Final self‐consistent field (SCF) and MP‐2 energy calculations were done with the DZ + Dc basis set augmented by diffuse functions. The ground state of 1 is the planar allyl anion (C2v). The rotation barrier in 1 is 21·1 kcal/mol at the MP‐2 level. The cyclopropyl carbanion is 27·0 kcal/mol higher in energy at the MP‐2 level. The perfluoroallyl anion is not planar, and the rotated structure is 25·7 kcal/mol more stable than the C2v structure at the MP‐2 level. The lowest energy structure on the potential energy surface for 2 is the perfluorocyclopropyl carbanion which is 27·8 kcal/mol more stable than the C2v structure at the MP‐2 level. The 1,1‐difluoroallyl anion is also not planar. Here the most stable structure on the potential energy surface is the rotated allyl anion which is 8·3 kcal/mol more stable than the all‐planar allyl anion structure.
Nonplanar phenyl ring and inverse order of solvolytic reactivity for tertiary benzylic substrates
Authors: Liu Kwang‐Ting , Kuo Mann‐Yan , Wang Yu 
Published: January 2005

AbstractThe rates of solvolysis of l‐aryl‐l‐phenyl‐2,2‐dimethylpropyl(1) p‐nitrobenzoates and of aryldiphenylmethyl‐p‐nitrobenzoates (2) were measured in 80% acetone. An inverse order of reactivity, k/km‐ CF3 > l was observed for 1 but not for 2. The X‐ray crystallogoraphic study of the parent compounds, l,l‐diphenyl‐2,2‐dimethylpropyl‐p‐nitrobenzoate (1b) and triphenylemethyl benzoate (3b), and of 2‐phenyl‐2‐propyl‐p‐nitrobenzoate (4) indicated that in the highly congested system 1 both phenyl rings were nonplanar, whereas the phenyl rings in 3 and 4 were essentially planar.
Oxygen‐atom transfer chemistry of α‐AZO hydroperoxides: Effect of competitive intramolecular hydrogen bonding and α‐methyl substitution
Authors: Baumstark Alfons L. , Vasquez Pedro C. 
Published: January 2005

Abstract1‐(Phenylazo)‐1‐(2‐pyridyl)ethyl hydroperoxide, 1, 1‐(phenylazo)‐1‐(2‐furyl)ethyl hydroperoxide, 2, phenylazo(2‐furyl)methyl hydroperoxide, 3, 1‐(phenylazo)‐1‐(4‐anisyl)ethyl hydroperoxide, 4, were synthesized in moderate yield by autoxidation of the phenylhydrazones in benzene. The ionic oxidation of benzyl methyl sulfide in benzene by 1‐4 yielded the sulfoxide and the metastable α‐azo hydroxides in essentially quantitative yield. The reaction was of the first order in α‐azo hydroperoxide and sulfide, respectively. The relative reactivity series found was: 1(1.0) <4(1.4) < phenylazo(4‐anisyl)methyl hydroperoxide 5 (2·9) <2 (3·8) < 3 (9·6). α‐Methyl substitution was found to slow the rate of oxygen‐atom trasfer by a factor of 2 to 2.5. The low relative reactivity of 1 was opposite that expected based on electronic effects. Competitive intramolecular hydrogen bonding of the hydroperoxy proton to the pyridyl nitrogen in 1 accounted for the observed result.
Homocub‐1(9)‐ene trapped
Authors: Chen Ning , Jones Maitland 
Published: January 2005

AbstractDecomposition of the tosylhydrazone salts formed from cubyl carboxaldehyde and homocubanone, potential precursors of cubylcarbene (5) and homocubanylidene (6), leads in each case to products derived from 6. It is suggested that homocub‐1(9)‐ene (7) is the active ingredient in the formation of 6 from both precursors. The hydrazones formed from N‐aziridylamines are useful photochemical sources of 6, and presumably other carbenes. Flash vacuum pyrolysis of the tosyl hydrazone salts and hydrazones at 600°C leads to indene.