bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyimide/Diamond Nanocomposites: Microstructure and Indentation Behavior
Authors: Zhang Qingxin , Naito Kimiyoshi , Tanaka Yoshihisa , Kagawa Yutaka 
Published: September 2007

AbstractPolyimide/diamond nanocomposites have been synthesized from 4,4′‐diaminodiphenyl ether (ODA) and 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA). All the polyimides show non‐crystalline X‐ray diffraction. The frequent occurrence of particular interatomic distances (R) denoted by the non‐crystalline X‐ray diffraction maxima are determined. An ultramicro‐indentation technique is employed to evaluate the effects of nano‐diamond particles on the indentation behavior of polyimides. Indentation size effect is observed and discussed.magnified image
Access to Poly{N‐[3‐(dimethylamino)propyl](meth)acrylamide} via Microwave‐Assisted Synthesis and Control of LCST‐Behavior in Water
Authors: Schmitz Sarah , Ritter Helmut 
Published: September 2007

AbstractIn the present paper, the microwave (MW)‐assisted synthesis of the alkaline N‐[3‐(dimethylamino)propyl]methacrylamide (4) and ‐acrylamide (5) monomers within minutes is described. The reaction was carried out by mixing and subsequent irradiation of 3‐dimethylamino‐1‐propylamine (3) and (meth)acrylic acid (1/2) without addition of solvent. After polymerization, the obtained homopolymers (6/7) exhibit lower critical solution temperature (LCST) behavior in water at 35 °C only at pH = 14. The LCST‐behavior can be influenced by N‐oxidation of the tertiary amino group with hydrogen peroxide or by formation of a polymer‐inclusion complex (6a) of 6 and β‐cyclodextrin (β‐CD) by addition of randomly‐methylated β‐CD.magnified image
Role of vitamin A elimination or supplementation diets during postnatal development on the allergic sensitisation in mice
Authors: Rühl Ralph , Hänel Andrej , Garcia Ada L. , Dahten Anja , Herz Udo , Schweigert Florian J. , Worm Margitta 
Published: September 2007

AbstractVitamin A (VA) and its derivatives, the retinoids, are important factors for the development of the immune system. It has been shown in adult animals that proliferation of lymphocyte populations and antibody secretion are retinoid dependent, while little is known about the effects of retinoids during postnatal development. The aim of this study was to investigate the role of VA on allergic sensitisation during lactation and after weaning using an in vivo system for postnatal allergic sensitisation in mice. Different VA diets (basal/VA elimination/VA (as retinyl palmitate) supplemented) were fed to the dams throughout lactation and directly to the pups after weaning. Allergic sensitisation was induced with a single peritoneal ovalbumin (OVA) injection at day 28 after weaning. The phenotype of lymphocytes was analysed by flow cytometry and functional data were obtained by analysis of (IL‐4/IFN‐γ) cytokine production and antibody production (OVA‐specific IgG1 and IgE) in the offspring. VA/retinyl palmitate supplementation during lactation and after weaning decreased CD3+, CD4+, CD8+ and B220+ populations in splenic lymphocytes but also significantly enhanced IL‐4 production and OVA‐specific IgE after sensitisation. In contrast, mice fed VA‐elimination diet displayed no significant alteration of lymphocyte numbers and a slightly increased IL‐4 production. Our results showed that a single allergen injection during postnatal development induces allergic sensitisation whose degree is modified by the VA content of the maternal diet during lactation and the diet of the pups after weaning, indicating an important role of VA on the severity of the allergic sensitisation.
Expression of gonadotropin and gonadotropin receptor genes during early sexual maturation in male Atlantic salmon parr
Authors: Maugars Gersende , Schmitz Monika 
Published: September 2007

AbstractAtlantic salmon males may mature already as small parr in freshwater. Sexual maturation in teleosts as in vertebrates is characterized by the activation of the brain–pituitary–gonad axis. The endocrine regulation of early puberty is still not well understood. In the present study, one‐summer‐old male Atlantic salmon parr were sampled regularly from December several months prior to the beginning of spermatogenesis until spawning in October. Pituitary expression levels of follicle‐stimulating hormone (FSH) and luteinizing hormone (LH) β subunit genes were analyzed in parallel with testis expression of FSH receptor (FSHR) and LH receptor (LHR) genes by RT‐PCR and plasma 11‐ketostestosterone (11‐KT) was measured. Expression levels of FSHβ, low during winter and spring started to increase prior to the onset of gonadal growth at the end of May while LHβ mRNA levels were hardly detectable. Both gonadotropin receptor genes were expressed in immature testis with FSHR transcripts being more abundant (8‐fold). FSHR transcript levels increased in parallel to FSHβ levels from early spermatogenesis onwards, while LHR mRNA started to increase prior to any large changes in LHβ expression. Both transcript levels of LHβ and LHR were highest during spermiation. Plasma 11‐KT increased at the beginning of spermatogenesis reaching highest levels at spermiogenesis suggesting a possible role of FSH in inducing 11‐KT production during early spermatogenesis while LH stimulates via its specific receptor 11‐KT production at spermiogenesis. The commitment into sexual maturation appears to be dependant on both the presence of FSHR in immature testis and the increase of FSH expression. Mol. Reprod. Dev. 75: 403–413, 2008. © 2007 Wiley‐Liss, Inc.
Osteopontin improves in vitro development of porcine embryos and decreases apoptosis
Authors: Hao Yanhong , Murphy Clifton N. , Spate Lee , Wax David , Zhong Zhisheng , Samuel Melissa , Mathialagan Nagappan , Schatten Heide , Prather Randall S. 
Published: September 2007

AbstractAn optimal environment for fertilization and early embryonic development is provided by the mammalian oviduct and uterus. The secretory cells lining the lumen of the oviduct and uterus synthesize and secrete proteins that have been shown to interact with and influence the activities of gametes and embryos. Western blotting in this study demonstrated that a 50‐kDa secreted phosphoprotein 1 (SPP1) form was present in the uterus on Days 0, 3, and 5 in pregnant and nonbred gilts, and the concentration of SPP1 on Day 0 was higher than on Days 3 and 5 in pregnant gilts, but in nonbred gilts the concentration of SPP1 on Day 0 was higher than Day 3, but not Day 5. In addition, we show that addition of 0.1 µg/ml SPP1 to the culture medium after fertilization increased the percent cleaved (24 hr: 23.6 ± 1.29a vs. 18.7 ± 0.65b (2‐cell %)), and the percent blastocyst (37.2 ± 1.12a vs. 30.9 ± 0.56b) derived from IVF (P < 0.05). In parthenogenetic‐derived embryos the percent cleaved was increased due to SPP1 at 24 hr (24.0 ± 1.59a vs. 19.7 ± 1.59b (>2‐cell %)), and at 48 hr (72.9± 2.99a vs. 63.3 ± 2.99b), but not the percent blastocyst. By TUNEL assay, SPP1 decreased both apoptosis (7.9 ± 0.04a vs. 13.1 ± 0.02b) and the percent fragmentation (45.2  ± 0.07a vs. 58.8  ± 0.03b). We conclude that SPP1 can improve development in vitro possibly by reducing the rate of apoptosis. Mol. Reprod. Dev. 75: 291–298, 2008. © 2007 Wiley‐Liss, Inc.
Cryogenic effect of antifreeze protein on transgenic mouse ovaries and the production of live offspring by orthotopic transplantation of cryopreserved mouse ovaries
Authors: Bagis Haydar , Akkoç Tolga , Tasş Arzu , Aktoprakligil Digdem 
Published: September 2007

AbstractThe purpose of the present study was to evaluate the cryogenic effect of antifreeze protein (AFP) on transgenic mouse ovaries which is expressed AFP type III from Ocean pout and the production of live offspring by orthotopic transplantation of cryopreserved mouse ovaries. In this study, whole transgenic and nontransgenic mouse ovaries were vitrified with 20% DMSO and 20% EG in M2 medium supplemented with 0.5 M sucrose. All vitrified and toxicity control and fresh ovaries were transplanted orthotopically into ovariectomized recipients bilaterally. For fresh ovaries transplantation, 5 mice delivered litters of 18 and 19 live pups in first and second matings, respectively. For toxicity control of chemicals, 6 mice delivered litters of 22 and 23 live pups. For nontransgenic mouse ovaries (vitrified) transplantation, 7 mice delivered litters of 22 and 23 live pups. For transgenic mouse ovaries (vitrified) transplantation, 10 mice delivered litters of 35 and 37 live pups. Litter sizes from pups of freshly transplanted ovaries were not significantly different from AFP‐transplanted transgenic ovaries but those from nontransgenic‐transplanted ovaries were significantly different from the AFP‐transplanted transgenic ovaries group (P < 0.05). In this study, for the first time, it was shown that the ovarian tissue of AFP transgenic mice was protected from cryopreservation by vitrification. These results demonstrate that a normal reproductive lifespan can be restored by orthotopic transplantation of AFP transgenic‐vitrified ovary. Mol. Reprod. Dev. 75: 608–613, 2008. © 2007 Wiley‐Liss, Inc.
Expression of the vascular endothelial growth factor‐receptor system in the porcine endometrium throughout the estrous cycle and early pregnancy
Authors: Kaczmarek Monika M. , Waclawik Agnieszka , Blitek Agnieszka , Kowalczyk Anna E. , Schams Dieter , Ziecik Adam J. 
Published: September 2007

AbstractThe objective of this study was to investigate the protein and mRNA expression of vascular endothelial growth factor (VEGF), VEGFR‐1 (fms‐like tyrosine kinase, Flt‐1) and VEGFR‐2 (fetal liver kinase‐1/kinase insert domain‐containing receptor, Flk‐1/KDR) in the endometrium during the estrous cycle and early pregnancy in pigs. The VEGF‐receptor system was localized in epithelial and stromal cells, blood vessels, and myometrium. Western blot analysis showed higher levels of VEGF protein during the periovulatory and periimplantation periods (P < 0.001, and P < 0.05, respectively). Constant expression of VEGF mRNA during the cycle and significant upregulation on Days 22–25 of gestation (vs. Days 9–17; P < 0.001) was observed. Stable levels of VEGFR‐1 mRNA and protein were detected in the endometrium of cyclic animals. However, higher VEGFR‐1 protein expression was found on Days 16–17 of the estrous cycle (P < 0.01) and Days 13–15 of gestation (P < 0.05). Protein expression of VEGFR‐2 was elevated on Days 2–4 of the estrous cycle (P < 0.001), but mRNA levels were constant during the cycle. In pregnancy, VEGFR‐2 protein expression started to increase after Day 15 (vs. Days 9–12; P < 0.05), but induction of VEGFR‐2 mRNA expression occurred earlier on Days 13–15. It appears from the present study that the VEGF‐receptor system is regulated in a temporal and spatial manner during the estrous cycle and early pregnancy in pigs. The results suggest that VEGF‐A family members are probably involved in appropriate preparation of endometrium for implantation and in vascular events during implantation in pigs. Mol. Reprod. Dev. 75: 362–372, 2008. © 2007 Wiley‐Liss, Inc.
Production of quail (Coturnix japonica) germline chimeras derived from in vitro‐cultured gonadal primordial germ cells
Authors: Park Tae Sub , Kim Mi A , Lim Jeong Mook , Han Jae Yong 
Published: September 2007

AbstractA previous report from our laboratory documented successful production of quail (Coturnix japonica) germline chimeras by transfer of gonadal primordial germ cells (gPGCs). Subsequently, this study was designed to evaluate whether gPGCs can be maintained in vitro for extended period, and furthermore, these cultured PGCs can induce germline transmission after transfer into recipient embryos. In experiment 1, gonadal cells from the two strains (wild‐type plumage (WP) and black (D) quail) were cultured in vitro for 10 days. Using antibody QCR1, we detected a continuous, significant (P = 0.0002) increase in the number of WP, but not D, PGCs. QCR1‐positive WP colonies began to form after 7 days in culture. On Day 10 of culture, 803 WP PGCs were present as a result of a continuous increase, whereas no D PGC colonies could be detected and the D gonadal stroma cells were rolled up. Differences in the PGCs or the gonadal stroma cells of the two different strains might account for these differences. In experiment 2, WP PGC colonies were maintained in vitro up to Day 20 of culture, and 10‐ or 20‐day‐cultured PGCs were microinjected into dorsal aortas of 181 recipient D embryos. Thirty‐five (19.3%) of the transplanted embryos hatched after incubation, and 25 (71.4%) of the hatchlings reached sexual maturity. Testcrossing of the sexually mature hatchlings resulted in three (10 days, 33.3%) and eight (20 days, 50.0%) germline chimeras respectively. This report is the first to describe successful production of germline chimera by transfer of in vitro‐cultured gPGCs in quail. Mol. Reprod. Dev. 75: 274–281, 2008. © 2007 Wiley‐Liss, Inc.
Estimation of effective stress parameter of unsaturated soils by using artificial neural networks
Authors: Kayadelen C. 
Published: September 2007

AbstractGreat efforts are required for determination of the effective stress parameter χ, applying the unsaturated testing procedure, since unsaturated soils that have the three‐phase system exhibit complex mechanical behavior. Therefore, it seems more reasonable to use the empirical methods for estimation of χ. The objective of this study is to investigate the practicability of using artificial neural networks (ANNs) to model the complex relationship between basic soil parameters, matric suction and the parameter χ. Five ANN models with different input parameters were developed. Feed‐forward back propagation was applied in the analyses as a learning algorithm. The data collected from the available literature were used for training and testing the ANN models. Furthermore, unsaturated triaxial tests were carried out under drained condition on compacted specimens. ANN models were validated by a part of data sets collected from the literature and data obtained from the current study, which were not included in the training phase. The analyses showed that the results obtained from ANN models are in satisfactory agreement with the experimental results and ANNs can be used as reliable tool for prediction of χ. Copyright © 2007 John Wiley & Sons, Ltd.
Chemical speciation by selective heteronuclear single‐quantum coherence spectroscopy: determination of double‐bond quantity in unsaturated fatty acid compounds
Authors: Tesiram Yasvir A. , Saunders Debra , Towner Rheal A. 
Published: September 2007

AbstractA method for identifying fatty acid species based on the number of double bonds contained in a lipid molecule is presented. Common to all polyunsaturated fatty acids are two signature resonances at ∼5.3 and 2.8 ppm in the proton chemical‐shift spectrum of NMR. These resonances are from the vinyl and bis‐allyl protons, respectively, and, although they can be readily observed by NMR from lipid extracts of biological samples, direct speciation has never been demonstrated by NMR. By modifying a conventional HSQC pulse sequence with a J‐pulse on the spin system of the vinyl group (generalized as an IS spin system) at the beginning of the initial polarization transfer period and selectively inverting the 13C (I) spins with a narrowband sech/tanh inversion pulse, the collection of data in both dimensions can be restricted to a narrow slice of the chemical‐shift range. The resolution is subsequently determined by digitizer efficiency, and spectra can be collected optimally from within a very narrow 1 × 6 ppm window of the respective proton and carbon chemical‐shift ranges. With this modification it is possible to distinguish at least one resonance each from the multiple shifts expected from the indirectly detected nuclei of the fatty acid species, oleic acid, linoleic acid, linolenic acid and arachidonic acid, which contain one, two, three and four double bonds, respectively. This and similar methods of applied selectivity are of potential interest in characterizing speciation in biological samples where mixtures are often encountered and chemical shifts of the same structural group of similar molecules give rise to complicated overlapping resonances but are important for diagnosis of disease processes such as cancer. Copyright © 2007 John Wiley & Sons, Ltd.
Effects of shadowing on photovoltaic module performance
Authors: Silvestre S. , Chouder A. 
Published: September 2007

AbstractA procedure of simulation and modelling PV modules' performance, working partially shadowed, is presented. Several shadow rates have been tested on a single cell forming part of a PV module having 36 solar cells serially connected, and the influence of shadow rate in most of the important PV module characteristic parameters has been evaluated.The correlation between PV module output lowering due to shadowing and the variation of resistive losses is also reported. Copyright © 2007 John Wiley & Sons, Ltd.
A computational study into the reactivity of epichlorohydrin and epibromohydrin under acidic conditions in the gas phase and aqueous solution
Authors: Shields E. S. , Merrill G. N. 
Published: September 2007

AbstractAb initio molecular orbital calculations have been carried out upon epichlorohydrin and epibromohydrin at the Hartree–Fock (HF) and Møller–Plesset (MP2) levels of theory to explore the reactivity of these species with respect to nucleophilic attack by water under acidic conditions in the gas phase and aqueous solution. These results suggest that nucleophilic attack occurs preferentially at the epoxy carbon atoms in both the gas phase and aqueous solution. These results are in contrast to those found for nucleophilic attack under basic conditions, where attack at the halocarbon atom is competitive with that at the epoxy carbon atoms. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis and optical properties of fluorene‐based polymers incorporating organosilicon unit
Authors: Takagi Koji , Kakiuchi Hiroki , Yuki Yasuo , Suzuki Masato 
Published: September 2007

AbstractThe synthesis and optical properties of polymers bearing the repeating unit of terfluorene and various organosilicon groups were investigated. Polymers with high molecular weight and good solubility could be obtained by Suzuki coupling polymerization from silylene‐containing fluorene‐based dibromo monomers and 9,9‐dihexylfluorene‐2,7‐bis(trimethyleneborate). From UV spectra of polymers bearing acyclic silylene bridge, the organosilicon units not only interrupted a π‐conjugation but also contributed to an electronic communication between connected fluorenes. The emission maximum wavelengths (ca. 400 nm) blue‐shifted when compared with that of polyfluorene (418 nm) and the fluorescence quantum yields were considerably high (>0.82) in the CHCl3 solution. On the other hand, rather broad emission was observed at 480 nm and the fluorescence quantum yield was quite low (0.004) in the solution‐state PL spectrum of tetraphenylsilole‐containing polymer. The polymer emitted visible green light in the spin‐coated film. The fluorescence peak intensity at 486 nm gradually decreased when the film was illuminated with the UV light of 359 nm in air. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4786–4794, 2007
Synthesis of ABCD‐type miktoarm star copolymers and transformation into zwitterionic star copolymers
Authors: Wang Xiaojun , He Junpo , Yang Yuliang 
Published: September 2007

AbstractABCD‐type 4‐miktoarm star copolymers of styrene (St), α‐methylstyrene (αMSt), tert‐butyl methacrylate (tBuMA), and 4‐vinylpyridine (4VP) were synthesized via anionic polymerization using 1,3‐bis(1‐phenylvinyl)benzene (m‐DDPE) as the linking molecule. The synthetic route was rationally designed with respect to the reactivity of individual propagating anion towards the double bond of m‐DDPE. Thus the synthesis includes several consecutive key reactions, for example, the monoaddition of polystyryllithium towards m‐DDPE, the polymerization of tBuMA initiated by the resulting monoadduct to produce a diblock macromonomer, the coupling of the macromonomer with poly(α‐methylstyryl)lithium to form a 3‐arm star anion, and the polymerization of 4‐vinylpyridine initiated by the star anion. These reactions were conducted either in a one‐pot process, in which the diblock macromonomer was in situ coupled with poly(α‐methylstyryl)lithium, or in a batch polymerization process, in which the same diblock macromonomer was separated. The final product was hydrolyzed to produce a zwitterionic miktoarm star copolymer, which was soluble at lower pH but insoluble in neutral and basic solution. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4818–4828, 2007
Segmented sulfonated poly(arylene ether sulfone)‐b‐polyimide copolymers for proton exchange membrane fuel cells. I. Copolymer synthesis and fundamental properties
Authors: Lee Hae‐Seung , Badami Anand S. , Roy Abhishek , McGrath James E. 
Published: September 2007

AbstractSegmented disulfonated poly(arylene ether sulfone)‐b‐polyimide copolymers based on hydrophilic and hydrophobic oligomers were synthesized and evaluated for use as proton exchange membranes (PEMs). Amine terminated sulfonated poly (arylene ether sulfone) hydrophilic oligomers and anhydride terminated naphthalene based polyimide hydrophobic oligomers were synthesized via step growth polymerization including high temperature one‐pot imidization. Synthesis of the multiblock copolymers was achieved by an imidization coupling reaction of hydrophilic and hydrophobic oligomers oligomers in a m‐cresol/NMP mixed solvent system, producing high molecular weight tough and ductile membranes. Proton conductivities and water uptake increased with increasing ion exchange capacities (IECs) of the copolymers as expected. The morphologies of the multiblock copolymers were investigated by tapping mode atomic force microscopy (TM‐AFM) and their measurements revealed that the multiblock copolymers had well‐defined nano‐phase separated morphologies which were clearly a function of block lengths. Hydrolytic stability test at 80 °C water for 1000 h showed that multiblock copolymer membranes retained intrinsic viscosities of about 80% of the original values and maintained flexibility which was much improved over polyimide random copolymers. The synthesis and fundamental properties of the multiblock copolymers are reported here and the systematic fuel cell properties will be provided in a separate article. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4879–4890, 2007
Effect of supercritical carbon dioxide on the crystallization behavior of poly(ether ether ketone)
Authors: Wang Dong , Gao Hong , Jiang Wei , Jiang Zhenhua 
Published: September 2007

AbstractThe supercritical CO2 (sc‐CO2) provided a moderate condition to make the amorphous CO2/poly(ether ether ketone) (PEEK) mixtures at 30 MPa and 40 °C. The crystal is obtained directly after treating CO2/PEEK mixture from 70 to 240 °C. The crystallization behavior of CO2/PEEK mixtures before and after treatment is investigated in detail by using differential scanning calorimetry (DSC), dynamic mechanical analysis, and wide‐angle X‐ray diffraction. DSC curves of CO2/PEEK samples showed the double cold crystallization peaks. The lower cold crystallization peak moves to higher temperature with the content of CO2 decreasing, and the higher cold crystallization peak keeps their temperatures at about 172 °C without a remarkable change. The dynamic mechanical spectrometry was also introduced to explain the relaxation behavior of the glass transition and crystallization. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2927–2936, 2007