bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fate of the first polar bodies in mouse oocytes
Authors: Miao Yiliang , Ma Suofeng , Liu Xinyong , Miao Deqiang , Chang Zhongle , Luo Mingjiu , Tan Jinghe 
Published: July 2004

AbstractBoth nuclear transfer and intracytoplasmic sperm injection (ICSI) practice necessitates studies on the spatial relationship between the MII spindle and the first polar bodies (FPB). Although recent observations have shown that the FPB position does not predict accurately the location of the meiotic spindle in metaphase II oocytes of monkey, hamster, and human, detailed studies on FPB deviation and its affecting factors are lacking. Since polar bodies can be used for genetic testing and oocyte quality grading, their life span under different conditions should be studied. The timing of formation and degeneration and the position relative to the MII spindle of the FPB and the factors affecting FPB deviation and degeneration during in vivo and in vitro aging of both in vivo and in vitro matured mouse oocytes were investigated in this study. Mice of the Kun‐ming breed were used, and the intact and degenerated FPB were identified through microscopic morphology in combination with propidium iodide (PI) exclusion test and the chromosomes visualized by Hoechst staining. Results are summarized as follows: (i) oocytes started FPB extrusion at 8 hr after the onset of in vivo or in vitro maturation, but the number of FPB reached maximum much later in vitro (14 hr of culture) than in vivo (10 hr post hCG). (ii) Some FPB began to degenerate before ovulation and around 70% became degenerated within 6 hr after maximal nuclear maturation both in vivo and in vitro; they disappeared faster during in vivo than in vitro aging but turned from intact to degenerated at a similar tempo. (iii) Some FPB began to deviate from the MII spindle 10 hr after hCG injection or in vitro culture and the distance between FPB and the spindle increased with time during both in vivo and in vitro aging. (iv) FPB deviated more slowly in the in vitro matured oocytes than in in vivo matured. (v) Denudation performed after FPB extrusion markedly enhanced its deviation. (vi) The perivitelline space (PVS) increased with time during maturation and aging in vivo and in vitro and the values of PVS and the percentages of FPB adjacent to the spindle were significantly negatively correlated. (vii) Cytochalasin B and colchicine had no effect on FPB deviation. (viii) None of the more than 3,500 FPBs observed was found to be dividing or have divided into two cells at any time points before or after ovulation or in vitro maturation. Our results were consistent with the possibility that the displacement of the FPB was a time‐ and PVS‐dependent process, indicating that PVS would increase with time and its formation and enlargement would facilitate the lateral displacement of the degenerating FPB. Mol. Reprod. Dev. 69: 66–76, 2004. © 2004 Wiley‐Liss, Inc.
Differential expression and activation of Stat3 during mouse embryo implantation and decidualization
Authors: Teng Chun‐Bo , Diao Hong‐Lu , Ma Xing‐Hong , Xu Li‐Bin , Yang Zeng‐Ming 
Published: July 2004

AbstractSignal transducer and activator of transcription (STATs) can be activated by many cytokines and growth factors. Stat3, a member of STAT family, is essential for embryonic development. Stat3 is specifically activated during mouse embryo implantation. This study was to investigate the expression, activation, and regulation of Stat3 in mouse uterus during early pregnancy, pseudopregnancy, delayed implantation, artificial decidualization, and hormonal treatments using in situ hybridization and immunohistochemistry. There was a strong level of Stat3 phosphorylation in the luminal epithelium only at the midnight of day 4 pregnancy, which coincides with attachment reaction between the blastocyst and luminal epithelium. However, there was no detectable Stat3 phosphorylation at the corresponding period during pseudopregnancy. On day 5 of pregnancy, Stat3 phosphorylation was strongly observed in the luminal epithelium and the stroma surrounding the implanting blastocyst at implantation sites, but not at the inter‐implantation sites. Stat3 phosphorylation was also not detected on day 5 of pseudopregnancy. Stat3 phosphorylation was at a high level in the decidual cells on days 6–8 of pregnancy. Under artificial decidualization, Stat3 was also phosphorylated in the decidual cells. In the ovariectomized mice, there was no Stat3 expression and activation in the uterus. Progesterone had no obvious effects. However, Stat3 mRNA expression and phosphorylation were significantly stimulated by estrogen treatment. Our data suggest that Stat3 phosphorylation may be important for mouse embryo implantation and decidualization, and may also be regulated by maternal estrogen. Mol. Reprod. Dev. 69: 1–10, 2004. © Wiley‐Liss, Inc.
Retinoid‐dependent mRNA expression and poly‐(A) contents in bovine oocytes meiotically arrested and/or matured in vitro
Authors: Gomez Enrique , Rodríguez Aida , Goyache Felix , Dd́ez Carmen , José Royo Luis , Moreira Pedro N. , Néstor Caamaño José , Morán Erica , Gutiérrez‐Adán Alfonso 
Published: July 2004

AbstractThe presence of retinoic acid (RA) during in vitro maturation (IVM) improves bovine oocyte quality and developmental potential. In this work, we investigated the underlying molecular mechanisms. Cumulus–oocyte complexes were meiotically arrested by roscovitine and/or matured in defined medium containing RA, 1% ethanol (vehicle), or no additives. Cumulus‐free oocytes were analyzed for poly‐(A) mRNA contents and relative mRNA expression of genes involved in cell cycle regulation (cyclin B1 and H1) and antioxidative defence (Mn‐superoxide dismutase and glucose‐6‐phosphate dehydrogenase). Poly‐(A) mRNA increased after meiotic inhibition and decreased with IVM completion, both in meiotically arrested and permissively matured oocytes, i.e., matured without previous meiotic arrest. RA dramatically increased poly‐(A) mRNA in meiotically arrested oocytes, but more than half of the poly‐(A) mRNA disappeared during maturation. Irrespective of oocyte origin, transcripts were detected for all the genes analyzed. IVM, with or without previous meiotic inhibition, increased expression of cyclin B1 and glucose‐6‐phosphate dehydrogenase, and decreased cyclin H1 and Mn‐superoxide dismutase. Except for a decreasing of Mn‐superoxide dismutase in meiotically arrested and matured oocytes, RA did not affect mRNA expression. Ethanol led to an abnormal poly‐(A) mRNA profile and expression of all the genes analyzed. RA does not modify expression of cyclin B1 and HI genes in the bovine oocyte, and probably does not generate oxidative stress. In addition, RA enhanced mRNA amount as measured by poly‐(A) mRNA contents. Mol. Reprod. Dev. 69: 101–108, 2004. © 2004 Wiley‐Liss, Inc.
Effect of paternal tamoxifen on the expression of insulin‐like growth factor 2 and insulin‐like growth factor type 1 receptor in the post‐implantation rat embryos
Authors: Kedia Neelam , Gill‐Sharma Manjit K. , Parte Priyanka , Juneja Harbans S. , Balasinor Nafisa 
Published: July 2004

AbstractNuclear transplantation studies demonstrated the importance of paternal contribution to embryogenesis. Paternal treatment with agents like cyclophosphamide and 5‐azacytidine has been shown to cause an increase in pre‐implantation loss (PIL) and post‐implantation loss (POL). Studies from our laboratory have shown that paternal tamoxifen treatment increases PIL and POL. It was observed that the PIL occurred at day 2 of gestation (embryo at 2–4 cell stage) and the POL occurred around day 9 of gestation (mid‐gestation). The insulin‐like growth factor (IGF) system represents one of the major growth‐controlling system expressed in the embryo. Several studies suggest that in rodents, insulin‐like growth factor 2 (Igf2) signaling through the insulin‐like growth factor type 1 receptor (Igf1r) modulates embryo growth at around days 9–11 of gestation (mid‐gestation). The present study was undertaken to evaluate the expression of Igf2 and Igf1r transcript by RT‐PCR in the post‐implantation embryos obtained after paternal tamoxifen treatment. It was observed that both the genes were down regulated in resorbed embryos (POL). Since Igf2 is an imprinted gene and the imprint mark is established during spermatogenesis, the present study suggests that paternal tamoxifen treatment may have affected imprinting of the gene during spermatogenesis thereby decreasing its expression and leading to increase in POL. This is to our knowledge the first study correlating the increase in post‐implantation embryo loss obtained after paternal drug treatment with the decrease in the expression of Igf2 in these embryos. Mol. Reprod. Dev. 69: 22–30, 2004. © 2004 Wiley‐Liss, Inc.
Transcutaneous magnetic stimulation of the quadriceps via the femoral nerve
Authors: Kremenic Ian J. , Ben‐Avi S. Simon , Leonhardt Dan , McHugh Malachy P. 
Published: July 2004

AbstractWe investigated the efficacy of different frequencies and intensities of magnetic stimulation for activating the quadriceps muscles; a painless method for stimulating the quadriceps would be useful in the rehabilitation of patients who have difficulty in voluntarily activating their muscles after injury or surgery. Eleven subjects underwent magnetic stimulation of the femoral nerve over a range of frequencies and intensities using a MagStim Rapid magnetic stimulator. Magnetic stimulation at 30 Hz at 80% of the power output of the stimulator used was capable of generating 72% of quadriceps maximal voluntary contraction torque. Subjects reported little or no pain during the procedure. Magnetic stimulation of the femoral nerve is a well‐tolerated way to activate the quadriceps muscles. Muscle Nerve 30: 379–381, 2004
β‐synemin localizes to regions of high stress in human skeletal myofibers
Authors: Mizuno Yuji , Guyon Jeffrey R. , Watkins Simon C. , Mizushima Kazuyuki , Sasaoka Toshikuni , Imamura Michihiro , Kunkel Louis M. , Okamoto Koichi 
Published: July 2004

AbstractSynemin is an intermediate filament protein shown previously to interact with α‐dystrobrevin and desmin. Immunoblot analysis detects a β‐synemin protein of 170 kDa in human skeletal muscle and an α‐synemin protein of 225 kDa in monkey brain. Low‐resolution immunohistochemical analysis localizes β‐synemin within muscle along the sarcolemma, whereas confocal microscopic analysis further refines localization to the costamere and muscle Z‐lines. In addition to these locations, β‐synemin is also enriched at the neuromuscular and myotendinous junctions, other regions that undergo high stress during myofiber contraction. Based on its localization and its expression pattern, it is proposed that β‐synemin functions as a structural protein involved in maintaining muscle integrity through its interactions with α‐dystrobrevin, desmin, and other structural proteins. Muscle Nerve 30: 337–346, 2004
Polystyrene magadiite nanocomposites
Authors: Wang Dongyan , Jiang David D. , Pabst Jaclyn , Han Zhidong , Wang Jianqi , Wilkie Charles A. 
Published: July 2004

AbstractAn organically modified magadiite has been prepared and used to make a mixed intercalated‐exfoliated polystyrene nanocomposite by bulk polymerization. This system gives excellent improvement in mechanical properties, but the thermogravimetric analysis curves do not show any change in the onset of the degradation and the degradation pathway is not changed from that for virgin polystyrene, unlike the situation for an aluminosilicate clay, montmorillonite. By cone calorimetry, the peak heat release rate is not changed, again unlike the results with the aluminosilicate. This suggests that not all clays exhibit the same behavior in nanocomposite formation. Polym. Eng. Sci. 44:1122–1131, 2004. © 2004 Society of Plastics Engineers.
Epoxy nanocomposites: Analysis and kinetics of cure
Authors: Ton‐That M.‐T. , Ngo T.‐D. , Ding P. , Fang G. , Cole K. C. , Hoa S. V. 
Published: July 2004

AbstractThe effect of organo‐nanoclay (Nanomer I30E) on the cure mechanism and kinetics of epoxy nanocomposites based on Epon 828 and Epicure 3046 was studied by means of dynamic differential scanning calorimetry (DSC) at four heating rates (2.5, 5, 10, and 20°C·min−1) and by Fourier transform infrared (FT‐IR) spectroscopy. The DSC cure data for epoxy‐amine mixtures with and without nanoclay was modeled by means of different approaches; the Kissinger and isoconversional models were used to calculate the kinetics parameters while the Avrami model was utilized to compare the cure behavior of the two systems. The Nanomer I30E was shown to initiate rapid homopolymerization of the Epon 828 resin at temperatures above 180°C. For the epoxy‐amine mixtures, the presence of nanoclay had little effect on the cure kinetics in the early stages (i.e., at lower temperatures), and the apparent activation energy was around 60 kJ·mol−1. However, in the later stages, the apparent activation energy increased significantly in the absence of nanoclay, but did not do so when it was present. The presence of nanoclay also lowered the final glass transition temperature by about 4°C. Polym. Eng. Sci. 44:1132–1141, 2004. © 2004 Society of Plastics Engineers.
Polyolefin nanocomposites: Essential work of fracture analysis
Authors: Bureau M. N. , Perrin‐Sarazin F. , Ton‐That M.‐T. 
Published: July 2004

AbstractThe tensile properties and the fracture toughness, based on the essential work of fracture (EWF) method, of melt‐compounded polymer nanocomposites based on polypropylene (PP) with organo‐modified clays (montmorillonite) and maleic anhydride (MA)–grafted PP coupling agents were studied. Depending on the compounding sequence and on whether a coupling agent was used, some improvements in tensile properties were observed. These improvements were related to the level of dispersion of clay particles. The highest tensile properties were obtained for the PP/clay compound showing the highest surface density of uniform sub‐micron particles. The mechanical improvements of the PP/clay compounds were those of a microcomposite in which the fiber reinforcement has an average aspect ratio of 17–35. The PP/clay compounds with coupling agents and with highest surface density of uniform sub‐micron particles showed very good fracture toughness, with EWF values slightly higher than those of unfilled PP. Fractographic observations showed that clay particles acted as void nucleation sites, which then grew and coalesced, promoting fibrillation of the remaining material between the voids. The EWF results indicated that the void nucleation density determined the fracture toughness. The EWF results also indicated that the plastic work dissipation related to the stability of the fibrillation, which was promoted by the use of a coupling agent. Polym. Eng. Sci. 44:1142–1151, 2004. © 2004 Society of Plastics Engineers.
Bending behavior of hydrogels composed of poly(methacrylic acid) and alginate by electrical stimulus
Authors: Kim Seon Jeong , Yoon Seoung Gil , Lee Yong Hee , Kim Sun I 
Published: July 2004

AbstractInterpenetrating polymer networks (IPNs) prepared from poly(methacrylic acid) (PMAAc) and sodium alginate (SA) exhibited electrical sensitive behavior. The swelling behavior of the PMAAc/SA IPN hydrogel was studied by immersion of the gel into aqueous HCl solutions at various concentrations and into various pH buffer solutions, and their responses to electric fields were also investigated. When swollen IPN hydrogel was placed between a pair of electrodes it exhibited bending behavior on application of an electric field, and showed stepwise bending behavior depending on the magnitude of the electrical stimulus. Copyright © 2004 Society of Chemical Industry
First hyperpolarizabilities of 1,3,5‐tricyano‐2,4,6‐tris(styryl)benzene derivatives: ab initio studies and Hammett correlation
Authors: Park Gyoosoon , Cho Bong Rae 
Published: July 2004

AbstractFirst hyperpolarizabilities (β) of the 1,3,5‐tricyano‐2,4,6‐tris(styryl)benzene derivatives were studied by an ab initio method (HF/6–31G). The β values of these molecules increase with increase in donor strength, reaching a maximum value of 262 × 10−30 esu with an oxyanion as the donor. Also, the electronic charge is more delocalized, and the HOMO–LUMO energy gap (ΔE) and the bond length alternation (BLA) decrease with the same variation of the donor. Noteworthy is the excellent linear relationship between β and 1/ΔE2 and σgas+. These results may serve as a useful guideline for the design of two‐dimensional octupoles with large first hyperpolarizabilities. Copyright © 2004 John Wiley & Sons, Ltd.
Tuning carbanion reactivity by complexing with boranes: γ‐elimination reaction as a model
Authors: Habusha Uri , Rozental Esther , Hoz Shmaryahu 
Published: July 2004

AbstractThe anion of 3‐chloro‐3‐phenylselenocyclobutanecarbonitrile undergoes in DME, in the presence of alcohols, competitive protonation and γ‐elimination reactions [Eqn (1)]. With highly acidic alcohols such as trifluoroethanol the protonation is diffusion controlled and the rate for the cross ring elimination reaction is greater by a factor of three (at an alcohol concentration of 1 M). However, in the presence of BH3 or Bu3B, the protonated product becomes dominant. This result is attributed to the binding of the carbanion by the boranes. Experimental data as well as ab initio calculations show that the preferred complexation site is the ring carbon and not the cyano nitrogen of the complex. The results also show that direct protonation of the complex is not a viable rationalization of the findings. It is suggested that the enhanced protonation results from the formation of a hydrogen bond between the alcohol and the cyano nitrogen, thus increasing the effective molarity of the proton donor which migrates to the α‐carbon upon dissociation of the C—B bond. Copyright © 2004 John Wiley & Sons, Ltd.
Preparation and Screening of Diboronate Arrays for Identification of Carbohydrate Binders
Authors: Hoeg‐Jensen Thomas 
Published: July 2004

AbstractBoronic acids and their anionic counterpart, boronates, are known to bind reversibly to polyols, such as carbohydrates, under aqueous conditions. Monoboronic acids generally display a common selectivity rank exemplified by fructose>galactose>mannose>glucose. This order can however be modulated by the use of diboronic acids, which may give increased selectivity for e.g. glucose. Diboronic acids have previously typically been prepared and tested individually, but this paper reports a solid‐phase method for parallel synthesis of diboronate arrays, along with visual screening of the compounds for carbohydrate binding by competitive binding to alizarin. Diboronate arrays were prepared based on Fmoc‐Lys(Boc) and related amino acids, and screening identified diboronates with enhanced affinity to melibiose and glucose.
Analysis of Water Solubility Data on the Basis of HYBOT Descriptors. Part 3. Solubility of Solid Neutral Chemicals and Drugs
Authors: Raevsky Oleg A. , Raevskaja Olga E. , Schaper Klaus‐Jürgen 
Published: July 2004

AbstractA detailed QSPR investigation of the water solubility (logS) of 1063 solid neutral chemicals, agrochemicals, drugs and prodrugs has been carried out. The application of the “General Solubility Equation” of Yalkowskyet al.resulted in a correlation between experimental and calculated solubility with rather modest statistic criteria. It was found that 191 compounds (18%) have calculated logS with deviations above one logarithmic unit. A comparison of experimental values with those calculated by an equation previously derived for liquid chemicals demonstrates that a part of the total set of compounds containing certain substructures such as chloroalkyls, phenyls, biphenyls, nitrogen (acyclic and in cycles), benzanthracenes, phenols, and chemicals with ether, ester, and N,N‐disubstituted carboxamide groups obey to the equation for liquids. Not unexpectedly, the other part of compounds containing both strong H‐bond acceptor and donor groups is essentially less soluble than calculated for compounds in the liquid state. It is proposed that this low solubility is connected with a specific H‐bond association of these compounds in their crystal lattice.
Dynamic Method of Determination of Octanol‐Water Partition Coefficient of 2,4‐Dihydroxythiobenzanilides in QSAR Studies
Authors: Persona Andrzej , Marczewska Barbara , Fekner Zygmunt , Senczyna Bogdan , Matysiak Joanna , Niewiadomy Andrzej 
Published: July 2004

AbstractThe dynamic method to determine the octanol‐water partition coefficient of 2,4‐dihydroxythiobenzanilides on the basis of the spectrophotometrical data was used. The spectrophotometric investigations of lipophilicity were based on the changes of absorbance in time as the result of permeation of analyte from the aqueous to the octanol phase. The interpretation of the data was based on the reference equation for the correlation of the experimental results and the calculated values obtained from the calibration process (log Pτ). The calculated log P values from three different approaches were used comparatively. The best correlation between the experimental log P values and those determined according to the Broto's method was found. The linear relationships between log P obtained in different ways and the logarithmically transformed 1/MIC values are presented. The strains of dermatophytes, moulds and yeasts were used as bioindicators. In comparison to the experimentally obtained log Pτ, the calculated log P values correlated better with bioactivity. Significantly higher correlation was found with the fungistatic activity determined on moulds and yeasts than on dermatophytes.
Unified analytical treatment of two‐electron multicenter integrals of central and noncentral interaction potentials over Slater orbitals
Authors: Guseinov I. I. 
Published: July 2004

AbstractThe complete orthonormal sets of Ψα‐exponential‐type orbitals (ETOs) (α = 1, 0, −1, −2, …) introduced by the author for expanding Slater‐type orbitals (STOs) enable two‐electron multicenter integrals of arbitrary central and noncentral interaction potentials (CIPs and NCIPs) to be reduced to one‐center two‐electron integrals. These one‐center integrals are advantageously reduced using Fourier convolution methods. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004