bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temporospatial expression of placental lactogen and prolactin‐related protein‐1 genes in the bovine placenta and uterus during pregnancy
Authors: Patel O.V. , Yamada O. , Kizaki K. , Todoroki J. , Takahashi T. , Imai K. , Schuler L.A. , Hashizume K. 
Published: July 2004

AbstractThe anatomical location of binucleate cells (BNC) influences protein expression but not steroid synthesis in ruminants. In order to determine if BNC in disparate locations differentially express bovine placental lactogen (bPL) and prolactin‐related protein‐1 (bPRP‐1), we quantitated bPL and bPRP‐1 transcripts in placentomal (cotyledonary, caruncular) and interplacentomal (intercotyledonary, intercaruncular) tissues throughout pregnancy in the bovine using real‐time reverse transcription PCR (RT‐PCR) and in situ hybridization. Levels of both bPL and bPRP‐1 transcripts at peri‐implantation were significantly higher (P < 0.01) in the fetal membrane than in caruncular and intercaruncular tissues. Thereafter, mRNA for these related proteins demonstrated different spatial as well as temporal patterns of expression. Levels of bPRP‐1 transcripts peaked at day 60 of pregnancy. Between day 60 and 100, bPRP‐1 transcripts fell by approximately sevenfold (P < 0.01) in cotyledonary and intercotyledonary tissues, and fourfold in caruncular (P < 0.01) tissue. Levels of bPRP‐1 transcripts remained low in the cotyledonary, intercotyledonary, and caruncular tissues until peripartum. In contrast, bPL expression in placentomes increased with progression of gestation (P < 0.01), but decreased in interplacentomal tissue around peripartum. To conclude, disparate patterns of bPRP‐1 and bPL genes are transcribed in the placentomal and interplacentomal tissues during gestation in the bovine, suggesting that these prolactin‐like hormones serve distinct functions and are regulated differently in the uteroplacental unit in this species. Mol. Reprod. Dev. 69: 146–152, 2004. © 2004 Wiley‐Liss, Inc.
Regulation of histone acetylation during meiotic maturation in mouse oocytes
Authors: Akiyama Tomohiko , Kim Jin‐Moon , Nagata Masao , Aoki Fugaku 
Published: July 2004

AbstractHistone acetylation is an important epigenetic modification implicated in the regulation of chromatin structure and, subsequently, gene expression. Global histone deacetylation was reported in mouse oocytes during meiosis but not mitosis. The regulation of this meiosis‐specific deacetylation has not been elucidated. Here, we demonstrate that p34cdc2 kinase activity and protein synthesis are responsible for the activation of histone deacetylases and the inhibition of histone acetyltransferases (HATs), respectively, resulting in deacetylation of histone H4 at lysine‐12 (H4K12) during mouse oocyte meiosis. Temporal changes in the acetylation state of H4K12 were examined immunocytochemically during meiotic maturation using an antibody specific for acetylated H4K12. H4K12 was deacetylated during the first meiosis, temporarily acetylated around the time of the first polar body (PB1) extrusion, and then deacetylated again during the second meiosis. Because these changes coincided with the known oscillation pattern of p34cdc2 kinase activity, we investigated the involvement of the kinase in H4K12 deacetylation. Roscovitine, an inhibitor of cyclin‐dependent kinase activity, prevented H4K12 deacetylation during both the first and second meiosis, suggesting that p34cdc2 kinase activity is required for deacetylation during meiosis. In addition, cycloheximide, a protein synthesis inhibitor, also prevented deacetylation. After PB1 extrusion, at which time H4K12 had been deacetylated, H4K12 was re‐acetylated in the condensed chromosomes by treatment with cycloheximide but not with roscovitine. These results demonstrate that HATs are present but inactivated by newly synthesized protein(s) that is (are) not involved in p34cdc2 kinase activity. Our results suggest that p34cdc2 kinase activity induces the deacetylation of H4K12 and that the deacetylated state is maintained by newly synthesized protein(s) that inhibits HAT activity during meiosis. Mol. Reprod. Dev. 69: 222–227, 2004. © 2004 Wiley‐Liss, Inc.
Production of transgenic rats by ooplasmic injection of spermatogenic cells exposed to exogenous DNA: A preliminary study
Authors: Kato Megumi , Ishikawa Ayako , Kaneko Ryosuke , Yagi Takeshi , Hochi Shinichi , Hirabayashi Masumi 
Published: July 2004

AbstractThe aim of the present study was to investigate the efficiencies of producing transgenic rats by the ooplasmic injection of sperm heads (intracytoplasmic sperm injection: ICSI) and elongating spermatids (elongating spermatid injection: ELSI) exposed to the EGFP DNA solution. A slightly lower proportion of ICSI oocytes using sperm heads exposed to a concentration of 0.5 μg/ml DNA solution for 1 min developed into offspring (13.3%, 48/361) when compared to that of oocytes injected with nontreated sperm heads (19.4%, 32/165). Eight ICSI offspring were found to be EGFP‐carrying transgenic rats (16.7% per offspring; 2.2% per embryo). After a 1‐min exposure of the elongating spermatids to 5 μg/ml of DNA solution, 8.8% (45/511) of the ELSI oocytes developed into offspring while 12.7% (22/173) of the ELSI oocytes using nontreated spermatids developed. Six ELSI offspring carried the EGFP DNA (13.3% per offspring; 1.2% per embryo). The conventional pronuclear microinjection of 5 μg/ml of DNA solution resulted in the higher production of offspring (29.7%, 104/350) and the birth of three transgenic rats (2.9% per offspring; 0.9% per embryo). Thus, sperm heads and elongating spermatids were practically useful as the vector of exogenous DNA if the DNA‐exposed spermatogenic cells were microinseminated into rat oocytes. Mol. Reprod. Dev. 69: 153–158, 2004. © 2004 Wiley‐Liss, Inc.
Isolation and characterization of a haploid germ cell specific sperm associated antigen 9 (SPAG9) from the baboon
Authors: Shankar S. , Mohapatra B. , Verma S. , Selvi R. , Jagadish N. , Suri A. 
Published: July 2004

AbstractPreviously, we cloned and sequenced a sperm specific antigen, designated as HSS (EMBL nomenclature human sperm associated antigen 9: hSPAG9) from human testis (Shankar et al.: Biochem Biophys Res Commun 243:561–565, 1998). The present study was conducted to isolate baboon proteomic homologue in order to find out whether the baboon can provide a suitable model for examining its immunocontraception effects. Baboon SPAG9 (bSPAG9) was cloned and sequenced from the baboon testis cDNA library. The baboon cDNA contained open reading frame encoding 760 amino acids. A 90.6 and 96.8% homology between baboon and human SPAG9 was found at protein and DNA levels. Analysis for tissue specificity by Northern blot procedure using various baboon tissues indicated that bSPAG9 was specifically expressed only in the baboon testis. Further, cell type expression analysis by in situ hybridization in baboon testis demonstrated the expression of bSPAG9 mRNA transcript only in the round spermatid suggesting haploid germ cell expression. Anti‐human SPAG9 antibodies recognized the acrosomal compartment region of baboon sperm in indirect immunofluorescence (IIF). Flow cytometry analysis showed surface localization of bSPAG9 in live baboon sperm. The amino acid sequence data for nonhuman primate SPAG9 suggest that antibodies generated by vaccinating baboon with hSPAG9 will recognize nonhuman primate SPAG9, supporting the testing of SPAG9 contraceptive vaccine based on hSPAG9 in the nonhuman primate model. Mol. Reprod. Dev. 69: 186–193, 2004. © 2004 Wiley‐Liss, Inc.
Isolation and characterization of a bovine trophectoderm cell line derived from a parthenogenetic blastocyst
Authors: Talbot Neil C. , Caperna Thomas J. , Powell Anne M. , Garrett Wesley M. , Ealy Alan D. 
Published: July 2004

AbstractA bovine trophectoderm cell line was established from a parthenogenetic in vitro‐produced blastocyst. To initiate the cell line, 8‐day parthenogenetic blastocysts were attached to a feeder layer of STO fibroblasts and primary outgrowths occurred that consisted of trophectoderm, endoderm, and very occasionally epiblast tissue. Any endoderm and epiblast outgrowths were removed from the primary cultures within the first 10 days of culture by dissection. One of the primary trophectoderm cell cultures was chosen for further propagation and was passaged by physical dissociation and replating on STO feeder cells. The cell culture, designated BPT‐1, was maintained in T25 flasks and passaged at a 1:3 split ratio for the first 15 passages approximately once every 2 weeks. Thereafter, the cell culture was passaged at 1:10–1:40 split ratios. Transmission electron microscopic examination showed the cells to be a polarized epithelium with apical microvilli, a thin basal lamina, and lateral junctions consisting of tight junctions and desmosomes. Lipid vacuoles and digestive vacuoles were also prominent features of the BPT‐1 cells. Metaphase spread analysis at passage 59 indicated a near diploid cell population (2n = 60) with a mode and median of 60 and a mean of 64. BPT‐1 cells secreted interferon‐tau into the medium as measured by anti‐viral assay and Western blot analysis. The cell line provides an in vitro model of parthenogenote trophectoderm whose biological characteristics can be compared to trophectoderm cell lines derived from bovine embryos produced by normal fertilization or nuclear transfer. Mol. Reprod. Dev. 69: 164–173, 2004. © 2004 Wiley‐Liss, Inc.
Exact static element stiffness matrices of non‐symmetric thin‐walled curved beams
Authors: Kim Nam‐II , Yun Hee‐Taek , Kim Moon‐Young 
Published: July 2004

AbstractAn evaluation procedure of exact static stiffness matrices for curved beams with non‐symmetric thin‐walled cross section are rigorously presented for the static analysis. Higher‐order differential equations for a uniform curved beam element are first transformed into a set of the first‐order simultaneous ordinary differential equations by introducing 14 displacement parameters where displacement modes corresponding to zero eigenvalues are suitably taken into account. This numerical technique is then accomplished via a generalized linear eigenvalue problem with non‐symmetric matrices. Next, the displacement functions of displacement parameters are exactly calculated by determining general solutions of simultaneous non‐homogeneous differential equations. Finally an exact stiffness matrix is evaluated using force–deformation relationships. In order to demonstrate the validity and effectiveness of this method, displacements and normal stresses of cantilever thin‐walled curved beams subjected to tip loads are evaluated and compared with those by thin‐walled curved beam elements as well as shell elements. Copyright © 2004 John Wiley & Sons, Ltd.
Accurate stresses in the thin‐layer method
Authors: Kausel Eduardo 
Published: July 2004

AbstractA method is described by means of which accurate strains and stresses can be obtained for problems of wave motion in laminated media modelled with the thin layer method (TLM), a semi‐discrete procedure that combines the power of finite elements with that of analytical solutions. It is shown that when the displacements in the TLM are combined with the consistent stresses at the layer interfaces, strains and stresses anywhere in the medium can be obtained with the same level of accuracy as the displacements. The proposed method thus circumvents the intrinsic problem that arises when strains are obtained via differentiation. As a bonus, it also renders the stresses continuous across layer interfaces, which is not the case when stresses are obtained via differentiation of the primary interpolation field. Copyright © 2004 John Wiley & Sons, Ltd.
Fatigue life prediction using 2‐scale temporal asymptotic homogenization
Authors: Oskay Caglar , Fish Jacob 
Published: July 2004

AbstractIn this manuscript, fatigue of structures is modelled as a multiscale phenomenon in time domain. Multiple temporal scales are introduced due to the fact that the load period is orders of magnitude smaller than the useful life span of a structural component. The problem of fatigue life prediction is studied within the framework of mathematical homogenization with two temporal co‐ordinates. By this approach the original initial boundary value problem is decomposed into coupled micro‐chronological (fast time‐scale) and macro‐chronological (slow time‐scale) problems. The life prediction methodology has been implemented in ABAQUS and validated against direct cycle‐by‐cycle simulations. Copyright © 2004 John Wiley & Sons, Ltd.
Exposure misclassification as a result of free sample drug utilization in automated claims databases and its effect on a pharmacoepidemiology study of selective COX‐2 inhibitors
Authors: Jacobus Susanna , Schneeweiss Sebastian , Chan K. Arnold 
Published: July 2004

AbstractPurposeFree drug samples are widely used in clinical practice. We were concerned about free sample drug utilization as a source of misclassification in pharmacoepidemiology research using claims data that may result in biased effect estimates.MethodsWe investigated the magnitude of potential bias with sensitivity analyses based on a published study that examined cardiovascular risk associated with selective cyclooxygenase 2 (COX‐2) inhibitors. We derived an estimate of free sample drug utilization with market data for rofexcoxib and calculated sensitivity of the exposure ascertainment method using claims data. We corrected the incidence rate ratio assuming the observed unexposed incidence rate was actually a weighted average rate of the truly unexposed and free sample drug users. The impact of exposure misclassification measured as the percentage change from a corrected to the reported crude incidence rate ratio was examined under a range of free sample drug utilization proportions and unexposed cohort sizes.ResultsThe proportion of free sample drug utilization of all rofecoxib use in our base case scenario was 15.48%, resulting in sensitivity of 84.52% for exposure ascertainment. The magnitude of bias was an underestimation of the unadjusted incidence rate ratio by 0.03%. With a free sample drug utilization proportion of 1.48% and the same unexposed cohort size of 237 975 person‐years, the underestimation was 0.003%. If the unexposed cohort were 975 person‐years given a 15.48% proportion, the underestimation was 8.82%.ConclusionsIn the pharmacoepidemiology study, we examined that uses claims data to ascertain drug exposure, our results suggest that adjustment for free sample drug utilization is probably not warranted. Copyright © 2004 John Wiley & Sons, Ltd.
Starch‐based nanocomposites by reactive extrusion processing
Authors: Kalambur Sathya B , Rizvi Syed SH 
Published: July 2004

AbstractNanocomposites with unique material properties have been prepared from synthetic plastics and nanosilicates (nanoclay) until now, but not from biopolymers such as starch. The primary challenge in making biopolymeric nanocomposites is to achieve strong adhesion between nanoclay and polymer matrix. For the first time nanocomposites with superior properties have been successfully made from starch‐polycaprolactone (PCL) blends in the presence of montmorillonite (MMT) nanoclay. Reactive extrusion results showed that addition of a modified nanoclay at 3 % wt level increased elongation almost fourfold over that of pristine starch–PCL blends. X‐ray diffractions results showed dispersion of clay in the polymer matrix. The nanocomposites have better solvent‐resistance properties because of resistance to diffusion offered by clay platelets in the polymer matrix. Copyright © 2004 Society of Chemical Industry
Comparative study of lignins from ultrasonic irradiated sugar‐cane bagasse
Authors: Sun J‐X , Xu F , Sun X‐F , Sun R‐C , Wu S‐B 
Published: July 2004

AbstractAfter ultrasonic irradiation of sugar‐cane bagasse (SCB) in distilled water at 55 °C for 40 min and continuing stirring for 80 min, the irradiated SCB was sequentially treated with 0.5 M NaOH, 0.5 %, 1.0 %, 1.5 %, 2.0 % and 3.0 % H2O2 at pH 11.5, and 2 M NaOH at 55 °C for 2 h, which solubilized 3.3, 59.7, 15.5, 4.4, 5.5, 1.7, 0.6 and 0.6 % of the original lignin, and 13.4, 38.2, 11.9, 4.5, 9.0, 2.4, 1.2, and 11.3 % of the original hemicelluloses, respectively. In total, the sequential extractions resulted in a release of 91.2 % of the original lignin and 91.9 % of the original hemicelluloses, which were higher than in the case of corresponding extractions without ultrasound pre‐treatment. The eight lignin fractions were comparatively characterized by chemical composition, structural features, molecular weights, and thermal stability using alkaline nitrobenzene oxidation, acid hydrolysis, UV, FT‐IR, 1H and 13CNMR spectroscopy, GPC, and thermal analysis. Compared to the lignins obtained without ultrasound, the lignin fractions prepared with the assistance of ultrasound had the same primary structure, composition, and similar or slightly higher purity. Copyright © 2004 Society of Chemical Industry
Platelet adhesion on a polyurethane surface grafted with a zwitterionic monomer of sulfobetaine via a Jeffamine spacer
Authors: Yuan J , Zhu J , Zhu CH , Shen J , Lin SC 
Published: July 2004

AbstractA possible approach to improve the blood compatibility of poly(ether urethane)s (PU) involves the covalent attachment of key molecules on its surface. The purpose of the present study was to design and synthesise a novel non‐thrombogenic biomaterial by modifying the surface of the PU with a zwitterionic monomer of sulfobetaine via a Jeffamine spacer. In this study, sulfobetaine was grafted onto a PU surface through the following reaction steps: (1) The PU surface was activated with hexamethylene diisocyanate (HDI) in toluene at 50 °C in the presence of di‐n‐butyltin dilaurate (DBTDL) as a catalyst. The extent of the reaction was measured by ATR‐FTIR spectra; a maximum number of free NCO groups was obtained after a reaction time of 90 min. (2) One cap of Jeffamine was reacted with isocyanate groups bound on the surface, so Jeffamine was introduced. (3) The PU surface terminated by Jeffamine was recoupled with isocyanate groups by HDI. (4) The hydroxyl groups of 4‐dimethylamino‐1‐butanol (DMAB) or 2‐dimethylaminoethanol (DMAE) were allowed to react with the isocyanate groups capped on Jeffamine. (5) Sulfobetaines were constructed on the surface through the ring‐opening reaction between tertiary amine and 1,3‐propanesultone (PS). It was confirmed by ATR‐FTIR and XPS that the grafted surfaces were composed of sulfobetaine. The results of the contact‐angle measurements and water absorption showed that they were strongly hydrophilic. The results of this platelet adhesion experiment as a preliminary test showed that PU grafted with sulfobetaine has good blood compatibility featured by the low platelet adhesion. Copyright © 2004 Society of Chemical Industry
Modeling extremely thin absorber solar cells for optimized design
Authors: Taretto K. , Rau U. 
Published: July 2004

AbstractExtremely thin absorber (ETA) solar cells based on inorganic semiconductors are theoretically analyzed by a model that considers the absorber as being a pin junction, with tunneling‐assisted defect recombination. Tunneling recombination turns out to be very important in ETA solar cells, owing to the high electrical fields in the absorber, which establishes a minimum thickness for the absorber layer, which is calculated to be around 15 and 20 nm for CdTe and CuInS2, respectively. Nevertheless, 15% efficient CdTe and CuInS2 ETA solar cells are possible, even at low diffusion lengths down to 10 nm. Additionally, the modeling provides optimum values for the thickness and number of absorber layers for CdTe and CuInS2 ETA solar cells, as a function of the minority‐carrier diffusion length and diffusion constant, for cells with and without light trapping. The calculations predict that light trapping serves two purposes: to enhance the cell efficiency by up to 5% absolute, and to use a simpler structure compared with the situation without light‐trapping. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis and photopolymerization of novel multifunctional vinyl esters
Authors: Lee Tai Y. , Kaung W. , Jönsson E. Sonny , Lowery K. , Guymon C. A. , Hoyle C. E. 
Published: July 2004

AbstractNovel mono‐ and multifunctional vinyl ester monomers containing thioether groups were synthesized via an amine‐catalyzed Michael addition reaction between vinyl acrylate and multifunctional thiols. Using photo‐differential scanning calorimetry and real‐time Fourier transform infrared (RTIR) spectroscopy, the polymerization kinetics and oxygen inhibition of the homopolymerizations of the vinyl ester monomers were investigated. The effect of the vinyl ester and thioether group on acrylate/vinyl ester and thiol/vinyl ester copolymerizations was determined using real‐time IR spectroscopy to monitor polymerization rates of acrylate, vinyl, and thiol groups simultaneously. Polymerization of the vinyl esters used was found to be relatively insensitive to oxygen inhibition. We propose that the thioether group is responsible for reducing oxygen inhibition by a series of chain transfer/oxygen‐scavenging reactions. In polymerization of a acrylate/vinyl ester mixture both in nitrogen and in air, the vinyl ester monomer significantly enhances the polymerization rates and the conversion of the acrylate double bonds via plasticization of the crosslinked matrix and reduction of inhibition by oxygen. Ultimately, the vinyl ester monomer is incorporated into the polymer network. Thiol/vinyl ester free‐radical copolymerization is much faster than either thiol/allylether copolymerization or vinyl ester homopolymerization. The electron‐rich vinyl ester double bonds ensure rapid copolymerization with thiol. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4424–4436, 2004
Kinetic study of the crosslinking reaction of 1,2‐polybutadiene with dicumyl peroxide in the absence and presence of vinyl acetate
Authors: Masaki Kohji , Ohkawara Shin‐ichi , Hirano Tomohiro , Seno Makiko , Sato Tsuneyuki 
Published: July 2004

AbstractThe crosslinking reaction of 1,2‐polybutadiene (1,2‐PB) with dicumyl peroxide (DCPO) in dioxane was kinetically studied by means of Fourier transform near‐infrared spectroscopy (FTNIR). The crosslinking reaction was followed in situ by the monitoring of the disappearance of the pendant vinyl group of 1,2‐PB with FTNIR. The initial disappearance rate (R0) of the vinyl group was expressed by R0 = k[DCPO]0.8[vinyl group]−0.2 (120 °C). The overall activation energy of the reaction was estimated to be 38.3 kcal/mol. The unusual rate equation was explained in terms of the polymerization of the pendant vinyl group as an allyl monomer involving degradative chain transfer to the monomer. The reaction mixture involved electron spin resonance (ESR)‐observable polymer radicals, of which the concentration rapidly increased with time owing to a progress of crosslinking after an induction period of 200 min. The crosslinking reaction of 1,2‐PB with DCPO was also examined in the presence of vinyl acetate (VAc), which was regarded as a copolymerization of the vinyl group with VAc. The vinyl group of 1,2‐PB was found to show a reactivity much higher than 1‐octene and 3‐methyl‐1‐hexene as model compounds in the copolymerization with VAc. This unexpectedly high reactivity of the vinyl group suggested that an intramolecular polymerization process proceeds between the pendant vinyl groups located on the same polymer chain, possibly leading to the formation of block‐like polymer. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4437–4447, 2004