bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of pre‐treating in vitro‐matured bovine oocytes with the cytoskeleton stabilizing agent taxol prior to vitrification
Authors: Morató Roser , Izquierdo Dolors , Albarracín José Luis , Anguita Begoña , Palomo María Jesús , Jiménez‐Macedo Ana Raquel , Paramio María Teresa , Mogas Teresa 
Published: May 2007

AbstractThe purpose of this study was to determine the efficacy of pre‐treating mature bovine oocytes with Taxol before vitrification by the open pulled Straw method (OPS). We evaluated the effects of pre‐treating the oocytes with 1 µM Taxol on chromosome organization, spindle morphology, cortical granule distribution and the ability of fertilized oocytes to develop to the blastocyst stage. After calf or cow oocyte vitrification without Taxol, significantly higher proportions of spindle abnormalities in the form of abnormal spindle structures or dispersed or decondensed chromosomes were observed compared to fresh control oocytes. In contrast, when we compared calf oocytes pre‐treated with Taxol before vitrification with control calf oocytes, similar percentages of oocytes showing a normal spindle morphology were observed. The percentages of oocytes with a peripheral cortical granule (CG) distribution increased when the oocytes were pretreated with Taxol and vitrified, while oocytes vitrified without Taxol pre‐treatment gave rise to higher cortical distribution percentages. Cleavage and blastocyst rates were significantly lower for vitrified versus untreated oocytes, both in cow and calf oocytes. Significantly higher cleavage rates were obtained when calf and cow oocytes were vitrified with Taxol. Pre‐treatment with Taxol before cow oocyte vitrification yielded significantly higher blastocyst rates. Calf oocytes, however, were unable to develop to the blastocyst stage, irrespective of previous Taxol treatment. These results indicate that the pre‐treatment of oocytes with Taxol before vitrification helps to reduce the damage induced by the cryopreservation process, and potentially improves the subsequent development of vitrified bovine oocytes. Summary sentence: Pre‐treatment of oocytes with Taxol before vitrification helps to reduce the damage induced by vitrification and potentially improves the development of vitrified bovine oocytes. Mol. Reprod. Dev. 75: 191–201, 2008. © 2007 Wiley‐Liss, Inc.
Immunocontraception in mice using repeated, multi‐antigen peptides: immunization with purified recombinant antigens
Authors: Hardy Christopher M. , Beaton Sandra , Hinds Lynette A. 
Published: May 2007

AbstractTwo immunocontraceptive antigens (AgE and AgF) were constructed that included different combinations of highly species‐specific peptides from the mouse reproductive antigens SP56, ZP3, ZP2, and ZP1 in the form of multi‐antigen peptides (MAPs). Both AgE and AgF contained three tandem repeats each of ZP2 and ZP3 peptide epitopes and a single copy of a ZP1 peptide sequence all of which had previously been demonstrated to individually have immunodominant or contraceptive effects. In addition, AgF contained a single contraceptive peptide derived from SP56, the putative ZP3 receptor protein on sperm. The antigens were expressed and affinity purified as recombinant repeated multi‐antigen (polyepitope) peptides using an Escherichia coli maltose binding protein (MBP) expression system. Female BALB/c mice actively immunized with these antigens in Freund's adjuvants produced variable serum antibody responses to the component peptides. Fertility rates for animals immunized with AgE (40%) and AgF (20%) were significantly reduced compared to MBP immunized mice (90%), but the reduction in fertility did not correlate with peptide‐specific serum antibody levels. Ovaries from all immunized mice appeared histologically normal with no evidence of oophoritis. These results demonstrate that high levels of immunocontraception can be achieved in mice, without apparent side‐effects, using species‐specific immunogens that include repeated peptides from proteins involved in fertilization. Mol. Reprod. Dev. 75: 126–135, 2008. © 2007 Wiley‐Liss, Inc.
The PKC pathway and in particular its β1 isoform is clearly involved in meiotic arrest maintenance but poorly in FSH‐induced meiosis resumption of the mouse cumulus cell enclosed oocyte
Authors: Denys Anne , Avazeri Nathalie , Lefèvre Brigitte 
Published: May 2007

AbstractPKC modulators were used to investigate the role of the PKC pathway either on the maintenance of meiotic arrest or on FSH‐induced maturation of mouse cumulus cell enclosed oocytes (CEOs). (1) Whereas PKC activation (PMA 8 µM) overcomed clearly the HX‐maintained meiotic arrest (83.7 ± 3.6% vs. 16.1 ± 10.6% GVBD oocytes), PKC inhibition (Calphostin C 100 nM) did not. On the contrary, it better maintained the meiotic arrest than HX alone. (2) No significant effect of PKC activation or inhibition was observed. (3) HX alone maintained PKCβ1 in the cytoplasm, whereas FSH and PKC activation induced partly its translocation into the nucleus. The results show that whereas the PKC pathway is clearly involved in maintenance of the meiotic arrest through PKCβ1, it is not involved in FSH‐induced meiosis of CEOs. Mol. Reprod. Dev. 74: 1575–1580, 2007. © 2007 Wiley‐Liss, Inc.
Expression of X‐linked genes in deceased neonates and surviving cloned female piglets
Authors: Jiang Le , Lai Liangxue , Samuel Melissa , Prather Randall S. , Yang Xiangzhong , Tian X. Cindy 
Published: May 2007

AbstractAnimal cloning through somatic cell nuclear transfer (NT) is very inefficient, probably due to insufficient reprogramming of the donor nuclei, which in turn would cause the dysregulation of gene expression. X‐Chromosome inactivation (XCI) is a multi‐step epigenetic process utilized by mammals to achieve dosage compensation in females. Our aim was to determine if any dysregulation of X‐linked genes, which would be indicative of unfaithful reprogramming of donor nuclei, was present in cloned pigs. Real time reverse transcription polymerase chain reaction (RT‐PCR) was performed to quantify the transcript levels of five X‐linked genes, X inactivation‐specific transcript (XIST), TSIX (the reverse spelling of XIST), hypoxanthine guanine phosphoribosyltransferase 1 (HPRT1), glucose‐6‐phosphate dehydrogenase (G6PD), V‐raf murine sarcoma 3,611 viral oncogene homolog 1 (ARAF1), and one autosomal gene, alpha‐1 type IV collagen (COL4A1) in major organs of neonatal deceased and surviving female cloned pigs as well as their age‐matched control pigs from conventional breeding. Aberrant expression level of these genes was prevalent in the neonatal deceased clones, while it was only moderate in cloned pigs that survived after birth. These results suggest a correlation between the viability of the clones and the normality of their gene expression and provide a possible explanation for the death of a large portion of cloned animals around birth. Mol. Reprod. Dev. 75: 265–273, 2008. © 2007 Wiley‐Liss, Inc.
Identification and gene expression profiling of the Pum1 and Pum2 members of the Pumilio family in the chicken
Authors: Lee Jee Young , Lim Jeong Mook , Kim Duk Kyung , Zheng Ying Hui , Moon Sunjin , Han Beom Ku , Song Ki DuK , Kim Heebal , Han Jae Yong 
Published: May 2007

AbstractMembers of the Pumilio (Pum) family of RNA‐binding proteins act as translational repressors and are required for germ cell development and asymmetric division. We identified the chicken Pum1 and Pum2 genes and analyzed their expression patterns in various tissues. Comparative sequence analysis of the Pum1 and Pum2 proteins from the drosophila, chicken, mouse, and human revealed a high degree of evolutionary conservation in terms of the levels of homology of the peptide sequences and the structure of Pumilio homology domain (PUM‐HD), C‐terminal RNA‐binding domain, with similar spacing between the adjacent Pum eight tandem repeats. In addition, phylogenetic patterns of pumilio family showed that Pum 1 and 2 of chicken are more closely related to those of mouse and human than other species and Pum1 is more conserved than Pum2. Using real‐time RT‐PCR, the expression levels of the Pum1 and Pum2 genes were found to be highest in hatched female gonads, and high‐level expression of Pum2 was detected in 12‐day and hatched gonads among the various chicken embryonic tissues tested. In adult tissues, the expression levels of Pum1 and Pum2 were expressed at higher levels in the testis and muscle than in any other tissue. The characteristics of the tissue‐specific expression of Pum genes suggest that Pum1 and Pum2 have effects crucially in particular stage during development of chicken gonads depending on sexual maturation. Mol. Reprod. Dev. 75: 184–190, 2008. © 2007 Wiley‐Liss, Inc.
Controller design for optimal tracking response in discrete‐time systems
Authors: Sebakhy O. A. , Yousef H. A. 
Published: May 2007

AbstractThe problem of designing a controller, which results in a closed‐loop system response with optimal time‐domain characteristics, is considered. In the approach presented in this paper, the controller order is fixed (higher than pole‐placement order) and we seek a controller that results in closed‐loop poles at certain desired and pre‐specified locations; while at the same time the output tracks the reference input in an optimal way. The optimality is measured by requiring certain norms on the error sequence—between the reference and output signals—to be minimum. Several norms are used. First, l2‐norm is used and the optimal solution is computed in one step of calculations. Second, l∞‐norm (i.e. minimal overshot) is considered and the solution is obtained by solving a constrained affine minimax optimization problem. Third, the l1‐norm (which corresponds to the integral absolute error‐(IAE)‐criterion) is used and linear programming techniques are utilized to solve the problem. The important case of finite settling time (i.e. deadbeat response) is studied as a special
case. Examples that illustrate the different design algorithms and demonstrate their feasibility are presented. Copyright © 2007 John Wiley & Sons, Ltd.
Novel highly elastic magnetic materials for dampers and seals: part II. Material behavior in a magnetic field
Authors: Abramchuk S. , Kramarenko E. , Grishin D. , Stepanov G. , Nikitin L. V. , Filipcsei G. , Khokhlov A. R. , Zrínyi M. 
Published: May 2007

AbstractThe combination of polymers with magnetic particles displays novel and often enhanced properties compared to the traditional materials. They can open up possibilities for new technological applications. The magnetic field sensitive elastomers represent a new type of composites consisting of small particles, usually from nanometer range to micron range, dispersed in a highly elastic polymeric matrix. In this paper, we show that in the presence of built‐in magnetic particles it is possible to tune the elastic modulus by an external magnetic field. We propose a phenomenological equation to describe the effect of the external magnetic field on the elastic modulus. We demonstrate the engineering potential of new materials on the examples of two devices. The first one is a new type of seals fundamentally different from those used before. In the simplest case, the sealing assembly includes a magnetoelastic strip and a permanent magnet. They attract due to the magnetic forces. This ensures that due to high elasticity of the proposed composites and good adhesion properties, the strip of magnetoelastic will adopt the shape of the surface to be sealed, this fact leading to an excellent sealing. Another straightforward application of the magnetic composites is based on their magnetic field dependent elastic modulus. Namely, we demonstrate in this paper the possible application of these materials as adjustable vibration dampers. Copyright © 2007 John Wiley & Sons, Ltd.
Revision of the dual substituent parameter treatment using the DFT‐calculated reaction energies
Authors: Exner Otto , Böhm Stanislav 
Published: April 2007

AbstractThe dual substituent parameter (DSP) data treatment is a broadly used procedure correlating the reaction energies or other physical quantities with two sets of substituent constants, inductive (σI) and resonance (σR). It was here revised using the most extensive sets of experimental reactivities available in the literature and two sets of reaction energies calculated at the level B3LYP/6‐311+G(d,p): acidities of 4‐substituted benzoic acids and 5‐(E)‐substituted penta‐2,4‐diene‐(E)‐acids with 19 or 15 common substituents. The latter two series enabled us to investigate the substituent effects more systematically than it was ever possible with the experimental data; this means in particular separate treatment of the undissociated acid molecules and of their anions, further separation of donor and acceptor substituents. In addition, the standard statistical treatment was improved when testing the significance of the resonance term.The DSP treatment is not valid generally, this applies both to the standard reference series and to the series commonly investigated. At best, DSP may be considered to hold for donor substituents but the effects of acceptors are much less variable and do not depend on the constants σR nor on any other measure of resonance. The small efficiency of acceptor substituents is due by the fact that the constant functional group (COOH in the standard series) is itself an acceptor. A correct treatment would be to investigate the donor and acceptor substituents separately, donors with an acceptor functional groups, and vice versa; substituents with weak resonance effect should be not included. The popularity and apparent success of the DSP treatment can be attributed to several grounds, most important has been the unbalanced choice of substituents. Copyright © 2007 John Wiley & Sons, Ltd.
Computational studies of the cyclization of thiosemicarbazides
Authors: Siwek Agata , Paneth Piotr 
Published: April 2007

AbstractWhile typically cyclodehydration of thiosemicarbazides in acidic media leads to 1,3,4‐thiadiazoles, we have recently shown that under reflux conditions in anhydrous acetic acid the cyclization yields an imidazolidine derivative. The mechanism of this reaction has been characterized theoretically. Calculations indicate that this direction, facilitated by the presence of the CH2CO2 moiety in the N4 substituent is favored over the direction leading toward the thiadiazole product. Formation of the CN bond that closes the five‐member ring appears to be concerted with the departure of ethanol molecule, although the proton transfer from the nitrogen atom to oxygen atom is much more advanced in the transition state. Copyright © 2007 John Wiley & Sons, Ltd.
Investigation of cation complexation behavior of azacrown ether substituted benzochromene
Authors: Fedorova O. A. , Maurel F. , Chebun'kova A. V. , Strokach Yu. P. , Valova T. M. , Kuzmina L. G. , Howard J. A. K. , Wenzel M. , Gloe K. , Lokshin V. , Samat A. 
Published: April 2007

AbstractThe study of the complex formation of 3,3‐diphenyl‐3H‐benzo[f]chromenes containing aza‐18‐crown‐6‐ether, diaza‐18‐crown‐6‐ether or morpholine units with alkali, alkaline earth, heavy and transition metal cations in acetonitrile is reported. The spectroscopic and kinetic behavior of the photomerocyanine isomers of these chromenes is strongly affected by complexation with a metal cation. In order to interpret some of experimental data, an ab initio theoretical analysis of photochromic‐crown ether and its cation complexes was conducted. The different site of coordination of mono‐ and divalent cations to determine the minimum‐energy structure of benzochromene complexes in gas phase as well as in acetonitrile as solvent was explored. The coordination of both carbonyl oxygen and crown‐ether macrocyle with divalent cations in carbonyl‐capped structure is found to be the most stable isomer in gas as well as in condensed media. The crown‐containing benzochromenes were studied in liquid‐liquid extraction experiments toward there capacity to transfer metallic salts from water into an organic phase.The high selectivity to extraction of Ag+ was found. Copyright © 2007 John Wiley & Sons, Ltd.
Rational design of a new class of diffusion‐inhibited HABI with fast back‐reaction
Authors: Iwahori Fumiyasu , Hatano Sayaka , Abe Jiro 
Published: April 2007

AbstractThe fast reversible photochromic molecule was synthesized with the aid of triphenylimidazolyl radicals (TPI˙) and naphthalene linker. The crystal structure, photochemical properties, and kinetics of the target compound (1,8‐TPID‐naphthalene) were investigated. 1,8‐TPID‐naphthalene photochemically cleaved into 1,8‐bisTPI˙‐ naphthalene and the color of the solution changed from colorless to green. ESR spectroscopy detected the light‐induced triplet radical pair in frozen matrix. After the UV irradiation is ceased, the back‐reaction of 1,8‐bisTPI˙‐naphthalene occurred by thermal conversion in the dark. The kinetic study on the back‐reaction revealed that the reaction obeys the first‐order kinetics with 2.04 s of half‐life time at 295 K. The activation energy and frequency factor of the back‐reaction were determined as 42.0 kJ/mol and 9.25 × 106 s−1, respectively. Copyright © 2007 John Wiley & Sons, Ltd.
Cumulative π‐π interaction triggers unusually high stabilization of linear hydrocarbons inside the single‐walled carbon nanotube
Authors: Dinadayalane T. C. , Gorb Leonid , Simeon Tomekia , Dodziuk Helena 
Published: May 2007

AbstractThe interactions of linear hydrocarbons C2nH4 and C2nH2 (n = 1–4) with a finite‐length armchair (5,5) single‐walled carbon nanotube have been investigated using HF and MP2 methods in conjunction with 6‐31G(d) basis set, and molecular mechanics (MM) with MM2 force field. In all cases, the results obtained at MP2/6‐31G(d) level show stabilization of these supramolecular systems, contrary to the repulsive interactions obtained with the HF method. The interaction energies computed using MM with MM2 force field are in close agreement with the results obtained using the MP2/6‐31G(d) level. They increase gradually as the length of linear hydrocarbon chain increases. The present study indicates that cumulative π‐π interaction is the origin for the exceptionally high stabilization of the long nanotube‐hydrocarbon complexes. Mulliken population analysis reveals a very small charge transfer between the nanotube and the guest. Essentially there is no change in HOMO‐LUMO energy gap by the insertion of linear hydrocarbons. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Dipole induced photodetachment dynamics of halide anions
Authors: Mondal Chandan Kumar 
Published: May 2007

AbstractIn this article the dynamics of photodetachment from closed shell anion in the presence of two color (bichromatic) laser field have been explored in the context of polar environmental situation. The electronic states of halide ions are modeled by a one dimensional Hamiltonian with a potential V(x) = −V0e. The two parameters V0 and σ are fixed by requiring V(x) to reproduce the experimentally observed ground state ionization energy of the halide ion concerned. The potential so generated are shown to support only one bound state. The time‐dependent Fourier grid Hamiltonian method is used to follow the detachment dynamics with fairly high intensities of light. The environmental effects on the dynamics are sought to be modeled by two ways i) allowing the well depth (V0) to fluctuate randomly V0(t) = V0[1+ΔVR(t)]; R(t) randomly fluctuates between +1 and −1 with time, when ΔV (strength of fluctuation) is fixed and ii) in the presence of perturbation produced by a neighboring solvent dipole, which changes the effective potential. The detachment rate constant is studied as a function of important system parameters of the used light field. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Nonempirical calculations of nonlinear optical properties of p‐nitroaniline in acetone: Comparison of supermolecule and semicontinuum approaches
Authors: Balakina Marina Yu. , Fominykh Olga D. 
Published: May 2007

AbstractThe comparison of the conventional continuum, supermolecule, and semicontinuum models for the description of solvent effect on the (hyper)polarizability of p‐nitroaniline (PNA) in acetone is performed. The supermolecule approach is used for the clusters containing PNA and one or two acetone molecules. The account of the specific solute–solvent interactions via the hydrogen bonds formation is shown to result in the enhancement of (hyper)polarizability values. The continuum approach exploited in the framework of polarizable continuum model (PCM) was shown to describe mainly the solvent effect on (hyper)polarizability. The semicontinuum approach, accounting explicitly the interaction between PNA and solvent molecules and treating the rest of the solvent as a continuum, results in a moderate increase of the (hyper)polarizability values compared to those obtained within the conventional PCM approach. All the calculations of (hyper)polarizabilities are performed at the Hartree–Fock level in the aug‐cc‐pVDZ' Dunning basis set. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Structure and relative energies of regioisomers and valence isomers of C60 adducts. HF and DFT study
Authors: Zverev Vladislav V. , Kovalenko Valeriy I. , Romanova Irina P. , Sinyashin Oleg G. 
Published: May 2007

AbstractFullerene C60 and N‐bridged C60NH regioisomeres are investigated by HF and DFT methods with BLYP, B3LYP and PBE functionals at the 6‐31G**, 6‐311G** and TZ2P levels. Method DFT/PBE/TZ2P, providing the good compliance with experimental results, is chosen. Cross‐sections of potential energy surface of adducts at a variation of 5,6‐ or 6,6‐ bonds lengths are investigated. It is shown, that C60C2H4NH and C60H2 are characterized by local minima for [5,6]‐closed forms, whereas local minima for [5,6]‐open forms are absent. So absence of stable conformations of the [5,6]‐closed forms of methanofullerenes and aziridinofullerenes is a consequence of strain energy in three‐membered rings. It is shown that relative stability of the regioisomers depends from the lengths of single or double bonds of monoadducts, participating in reactions. The coordinated change of relative energies of the open and closed isomers N‐bridged mono‐(C60NR 1–7) and bis‐adducts (C60(NR)2 8–14) is revealed. The [6,6]‐closed form is more stable for compounds C60NR (2,3) and cis‐1‐C60 (NR)2 (9,10) (R = Me, Ph), while [5,6]‐open and cis‐1 [6,6]‐open forms are more stable for compounds C60NR (6,7) and cis‐1‐C60(NR)2 (13,14) (R = COOMe, R*‐the nitropyrimidine), what has been confirmed by experiment. The factors, defining relative isomers stability are investigated. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Adjusting Moran'sIfor population density
Authors: Oden Neal 
Published: April 2007

AbstractI derive two new statistics,IpopandI*pop, that adjust Moran'sIto study clustering of disease cases in areas (for example, counties) with different, known population densities. A simulation of Lyme disease in Georgia suggests that these new statistics can be more powerful than those currently in use. This is because they consider both spatial pattern and non‐binomial variance in rates as evidence supporting disease clusters.
A direct approach for correcting aids incidence: Variance formula and comparison with other methods
Authors: Alioum Ahmadou , Commenges Daniel 
Published: April 2007

AbstractWe present a direct approach for correcting the acquired immunodeficiency syndrome (AIDS) incidence data for reporting delays, based on a non‐parametric method for the analysis of right truncated data. We show that the proposed method when applied for grouped data is equivalent to three other published methods. We give a simple formula for the variance of the estimated AIDS incidence. Both estimator and variance are assessed in a simulation study. It is important for the estimation of AIDS incidence in the last quarter of the period under consideration to use month rather than quarter or half‐year as the time unit for the analyses. The method is illustrated using data from the United States Centers for Disease Control.