bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modification of actions of heat shock on development and apoptosis of cultured preimplantation bovine embryos by oxygen concentration and dithiothreitol
Authors: de Castro e Paula L.A. , Hansen P.J. 
Published: February 2008

AbstractPreimplantation embryos exposed to elevated temperatures have reduced developmental competence. The involvement of reactive oxygen species in these effects has been controversial. Here we tested hypotheses that (1) heat shock effects on development and apoptosis would be greater when embryos were cultured in a high oxygen environment (air; oxygen concentration = ∼20.95%, v/v) than in a low oxygen environment (5% oxygen) and (2) that these effects would be reversed by addition of the antioxidant dithiothreitol (DTT). Heat shock of 41°C for 9 hr reduced development of two‐cell embryos and Day 5 embryos to the blastocyst stage embryos when in high oxygen. There was no effect of heat shock on development when embryos were in low oxygen. Furthermore, induction of TUNEL‐positive cells in Day 5 embryos by heat shock only occurred when embryos were in high oxygen. Addition of DTT to two‐cell embryos either did not reduce effects of a heat shock of 41°C for 15 hr on development or caused slight protection only. In contrast, treatment of Day 5 embryos with DTT reduced effects of heat shock on development and apoptosis. In summary, oxygen tension was shown to be a major determinant of the effects of heat shock on development and apoptosis in preimplantation bovine embryos. Protective effects of the antioxidant DTT were stage specific and more pronounced at later stages of development. Mol. Reprod. Dev. 75: 1338–1350, 2008. © 2008 Wiley‐Liss, Inc.
Mos 3′ UTR regulatory differences underlie species‐specific temporal patterns of Mos mRNA cytoplasmic polyadenylation and translational recruitment during oocyte maturation
Authors: Prasad C. Krishna , Mahadevan Mahendran , MacNicol Melanie C. , MacNicol Angus M. 
Published: February 2008

AbstractThe Mos proto‐oncogene is a critical regulator of vertebrate oocyte maturation. The maturation‐dependent translation of Mos protein correlates with the cytoplasmic polyadenylation of the maternal Mos mRNA. However, the precise temporal requirements for Mos protein function differ between oocytes of model mammalian species and oocytes of the frog Xenopus laevis. Despite the advances in model organisms, it is not known if the translation of the human Mos mRNA is also regulated by cytoplasmic polyadenylation or what regulatory elements may be involved. We report that the human Mos 3′ untranslated region (3′ UTR) contains a functional cytoplasmic polyadenylation element (CPE) and demonstrate that the endogenous Mos mRNA undergoes maturation‐dependent cytoplasmic polyadenylation in human oocytes. The human Mos 3′ UTR interacts with the human CPE‐binding protein and exerts translational control on a reporter mRNA in the heterologous Xenopus oocyte system. Unlike the Xenopus Mos mRNA, which is translationally activated by an early acting Musashi/polyadenylation response element (PRE)‐directed control mechanism, the translational activation of the human Mos 3′ UTR is dependent on a late acting CPE‐dependent process. Taken together, our findings suggest a fundamental difference in the 3′ UTR regulatory mechanisms controlling the temporal induction of maternal Mos mRNA polyadenylation and translational activation during Xenopus and mammalian oocyte maturation. Mol. Reprod. Dev. 75: 1258–1268, 2008. © 2008 Wiley‐Liss, Inc.
Molecular electron paramagnetic resonance imaging of melanin in melanomas: a proof‐of‐concept
Authors: Vanea Emilia , Charlier Nicolas , DeWever Julie , Dinguizli Mustapha , Feron Olivier , Baurain Jean‐François , Gallez Bernard 
Published: February 2008

AbstractThe incidence of malignant melanoma is increasing at an alarming rate. As the clinical outcome of the disease strongly depends on the localization of the lesion, early detection at the initial stages of development is critical. Here, we suggest spatial characterization of melanoma based on the presence of endogenous stable free radicals in melanin pigments. Taking into account the abundance of these naturally occurring free radicals in proliferating melanocytes and their localization pattern, we hypothesized that electron paramagnetic resonance (EPR) imaging could be a unique tool for mapping melanomas with high sensitivity and high resolution. The potential of EPR to image melanoma samples was demonstrated in vitro in animal and human samples. Using EPR systems operating at low frequency, we were also able to record in vivo EPR spectra and images from the melanin present in a subcutaneous melanoma implanted in a mouse. In addition to the proof‐of‐concept and the achievement of providing the first non‐invasive image of an endogenous radical, this technology may represent a key advance in improving the diagnosis of suspected melanoma lesions. Copyright © 2008 John Wiley & Sons, Ltd.
Convergence analysis of the Newton–Shamanskii method for a nonsymmetric algebraic Riccati equation
Authors: Lin Yiqin , Bao Liang 
Published: February 2008

AbstractIn this paper, we consider the nonsymmetric algebraic Riccati equation arising in transport theory. An important feature of this equation is that its minimal positive solution can be obtained via computing the minimal positive solution of a vector equation. We apply the Newton–Shamanskii method to solve the vector equation. Convergence analysis shows that the sequence of vectors generated by the Newton–Shamanskii method is monotonically increasing and converges to the minimal positive solution of the vector equation. Numerical experiments show that the Newton–Shamanskii method is feasible and effective, and outperforms the Newton method. Copyright © 2008 John Wiley & Sons, Ltd.
An improved numerical scheme for the sine‐Gordon equation in 2+1 dimensions
Authors: Bratsos A. G. 
Published: February 2008

AbstractA rational approximant of order 4, which is applied to a three‐time‐level recurrence relation, is used to transform the initial/boundary‐value problem associated with the two‐dimensional sine‐Gordon (SG) equation arising in the Josephson junctions problem. The resulting non‐linear system, which is analyzed for stability, is solved using an appropriate predictor–corrector (P–C) scheme, in which an explicit scheme of order 2 is used as predictor. For the implementation of the corrector, in order to avoid extended matrix evaluations, an auxiliary vector was successfully introduced. In this P–C scheme, a modification in the corrector has been proposed according to which the already evaluated corrected values are considered. The behavior of this P–C scheme is tested numerically on line and ring solitons known from the bibliography regarding the SG equation and conclusions for both undamped and damped problems are derived. Copyright © 2008 John Wiley & Sons, Ltd.
The Hu–Washizu variational principle for the identification of imperfections in beams
Authors: Caddemi S. , Di Paola M. 
Published: February 2008

AbstractThis paper presents a procedure for the identification of imperfections of structural parameters based on displacement measurements by static tests. The proposed procedure is based on the well‐known Hu–Washizu variational principle, suitably modified to account for the response measurements, which is able to provide closed‐form solutions to some inverse problems for the identification of structural parameter imperfections in beams. Copyright © 2008 John Wiley & Sons, Ltd.
Modal validation of sandwich shell finite elements based on a p‐order shear deformation theory including zigzag terms
Authors: Sulmoni Mattia , Gmür Thomas , Cugnoni Joël , Matter Marco 
Published: February 2008

AbstractThis paper describes a set of improved C0‐compatible composite shell finite elements for evaluating the global dynamic response (natural frequencies and mode shapes) of sandwich structures. Combining a through‐the‐thickness displacement approximation of variable high order with a first‐order zigzag function, the proposed finite elements are suited for modelling sandwich plates and doubly curved shells with a non‐uniform thickness and are more accurate than conventional models based on the first‐ and third‐order shear deformation theories, especially in sandwich panels with highly heterogeneous properties. The new finite element model is then validated by a comparison with the standard shell and 3D solid models. From these investigations, it can be concluded that adding a zigzag function even to high‐order polynomial approximations of the through‐the‐thickness displacement is a useful tool for refining the modelling of sandwich structures. In addition, the proposed formulation is sufficiently versatile to represent with the same level of accuracy the behaviour of thin‐to‐thick laminated shells as well as of strongly heterogeneous sandwich structures. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis and characterization of N‐substituted polyaniline with mesogen molecules
Authors: Gheybi Homa , Bagheri Massoumeh , Alizadeh Zahra , Entezami Ali Akbar 
Published: February 2008

AbstractThe N‐substituted polyaniline (PANi) was synthesized by incorporation of bromine‐terminated mesogens onto the emeraldine form of polyaniline. Firsty three liquid crystalline molecules containing biphenyl units were synthesized. These mesogenic molecules are named as: 6‐bromo‐ (4‐hexyloxy‐biphenyl‐4′‐oxy) hexane (C6C6Br), 5‐bromo‐(4‐hexyloxy‐biphenyl‐4′‐oxy) pentane (C6C5Br), 6‐bromo‐(4‐octyloxy‐biphenyl‐4′‐oxy) hexane (C8C6Br). Differential scanning calorimetry (DSC) in combination with polarizing optical microscopy (POM) were used to investigate the thermal properties of them. Optical microscopy showed focal conic texture characteristic of the Smectic A phase for (C6C5Br) and (C8C6Br). For (C6C6Br) smectic phase was determined. DSC experiments were also found in accord with mesophase formation. For the synthesis of N‐substituted polyaniline with these mesogen molecules, the emeraldine base polyaniline was reacted with BuLi to produce the N‐anionic polyaniline and then deprotonated polyaniline was reacted with bromine‐end mesogen to prepare mesogen‐substituted polyaniline through N‐substitution reaction. The degree of N‐substitution can be controlled by adjusting the molar feed ratio of mesogen to the number of repeat units of PANi. The microstructure and compositions of obtained polymers were characterized by FT‐IR, elemental analysis, DSC, and scanning electron microscopy (SEM). The cyclicvoltammetry show that the electroactivity of N‐substituted polyaniline is strongly dependent on the degree of N‐grafting. The solubility of mesogen‐substituted polyaniline in common organic solvents such as THF and chloroform was improved by increasing the degree of N‐substitution and also the samples are partially soluble in xylene. Liquid crystalline behavior of mesogen‐substituted polyanilines was investigated via POM, but no mesophase was observed. Copyright © 2008 John Wiley & Sons, Ltd.
Transplantation of human fetal mesenchymal stem cells improves glomerulopathy in a collagen type Iα2‐deficient mouse
Authors: Guillot PV , Cook HT , Pusey CD , Fisk NM , Harten S , Moss J , Shore I , Bou‐Gharios G 
Published: February 2008

AbstractFetal mesenchymal stem cell (fetal MSC) therapy has potential to treat genetic diseases with early onset, including those affecting the kidney and urinary tract. A collagen type Iα2‐deficient mouse has a deletion in the α2 chain of the procollagen type I gene, resulting in the synthesis of abnormal α1(I)3 homotrimers, which replace normal α1(I)2α2(I)1 heterotrimers and a glomerulopathy. We first confirmed that col1α2‐deficient homozygous mice show abnormal collagen deposition in the glomeruli, which increases in frequency and severity with postnatal age. Intrauterine transplantation of human MSCs from first trimester fetal blood led postnatally to a reduction of abnormal homotrimeric collagen type I deposition in the glomeruli of 4–12 week‐old col1α2‐deficient mice. Using bioluminescence imaging, in situ hybridization and immunohistochemistry in transplanted col1α2‐deficient mice, we showed that the damaged kidneys preferentially recruited donor cells in glomeruli, around mesangial cells. Real‐time RT–PCR demonstrated that this effect was seen at an engraftment level of 1% of total cells in the kidney, albeit higher in glomeruli. We conclude that intrauterine transplantation of human fetal MSCs improves renal glomerulopathy in a collagen type I‐deficient mouse model. These data support the feasibility of prenatal treatment for hereditary renal diseases. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Prenatal diagnosis of cystic fibrosis: the 18‐year experience of Brittany (western France)
Authors: Scotet Virginie , Duguépéroux Ingrid , Audrézet Marie‐Pierre , Blayau Martine , Boisseau Pierre , Journel Hubert , Parent Philippe , Férec Claude 
Published: February 2008

AbstractObjectiveThis study reports 18 years of experience in prenatal diagnosis (PD) of cystic fibrosis (CF) in a region where CF is frequent and the uptake of PD is common (Brittany, western France).MethodAll PDs made over the period 1989–2006 in women living in Brittany were collected.ResultsWe recorded 268 PDs made in 1 in 4 risk couples, plus 22 PDs directly made following the sonographic finding of echogenic bowel. Most of the 268 PDs were done in couples already having CF child(ren) (n = 195, 72.8%). Close to one‐fifth followed cascade screening (n = 49, 18.3%), which identified 26 new 1 in 4 risk couples among the relatives of CF patients or of carriers identified through newborn screening (NBS). The remaining PDs were mainly made in couples whose 1 in 4 risk was evidenced following the diagnosis of echogenic bowel in a previous pregnancy (n = 22, 8.2%). Although patients' life expectancy has considerably improved, in our population the great majority of couples chose pregnancy termination when PD indicated that the foetus had CF (95.9%).ConclusionThis study describes the distribution of PDs according to the context in which the 1 in 4 risk was discovered and highlights the real decisions of couples as regards pregnancy termination after a positive PD. Copyright © 2008 John Wiley & Sons, Ltd.
Ovarian cancer proteomics: Many technologies one goal
Authors: Narasimhan Kothandaraman , Changqing Zhao , Choolani Mahesh 
Published: February 2008

AbstractThe last decade has seen major changes in the technologies used to identify markers for diagnosing cancer. This review focuses on recent developments on the evolving field of biomarker discovery, and validation techniques using proteomics platforms for ovarian cancer. It is possible now to diagnose various disease conditions using microliter quantities of body fluids. Currently the major developments were made in three distinct areas: (i) protein profiling, (ii) high‐throughput validation techniques, and (iii) solid and liquid phase protein microarray platforms for analyzing candidate markers across subclasses and stages of cancers. The recent addition to the long list of technologies is metabolomics using metabolite profiling and informatics‐based filtering of information for biomarker discovery of ovarian cancer. Emerging technologies need to address ways to eliminate the limitations posed by the complex dynamic nature of body fluids as well as ways to enrich low‐abundance tumor markers if they were to become a successful biomarker discovery tool. These new technologies hold significant promise in identifying more robust markers for ovarian cancer. Since the prevalence of this disease in the population is low, the test must have a high specificity.
Oxidation of proteins: Basic principles and perspectives for blood proteomics
Authors: Barelli Stefano , Canellini Giorgia , Thadikkaran Lynne , Crettaz David , Quadroni Manfredo , Rossier Joël S. , Tissot Jean‐Daniel , Lion Niels 
Published: February 2008

AbstractProtein oxidation mechanisms result in a wide array of modifications, from backbone cleavage or protein crosslinking to more subtle modifications such as side chain oxidations. Protein oxidation occurs as part of normal regulatory processes, as a defence mechanism against oxidative stress, or as a deleterious processes when antioxidant defences are overcome. Because blood is continually exposed to reactive oxygen and nitrogen species, blood proteomics should inherently adopt redox proteomic strategies. In this review, we recall the biochemical basis of protein oxidation, review the proteomic methodologies applied to analyse redox modifications, and highlight some physiological and in vitro responses to oxidative stress of various blood components.
Phosphoproteomics: A possible route to novel biomarkers of breast cancer
Authors: Metodiev Metodi , Alldridge Louise 
Published: February 2008

AbstractProteomics is rapidly transforming the way that cancer and other pathologies are investigated. The ability to identify hundreds of proteins and to compare their abundance in different clinical samples presents a unique opportunity for direct identification of novel disease markers. Furthermore, recent advances allow us to analyse and compare PTMs. This gives an additional dimension for defining a new class of protein biomarker based not only on abundance and expression but also on the occurrence of covalent modifications specific to a disease state or therapy response. Such modifications are often a consequence of the activation/inactivation of a particular disease related pathway. In this review we evaluate the available information on breast cancer related protein‐phosphorylation events, illustrating the rationale for investigating this PTM as a target for breast cancer research with eventual clinical relevance. We present a critical survey of the published experimental strategies to study protein phosphorylation on a system wide scale and highlight recent specific advances in breast cancer phosphoproteomics. Finally we discuss the feasibility of establishing novel biomarkers for breast cancer based on the detection of patterns of specific protein phosphorylation events.
Modulation of cancer cell line differentiation: A neglected proteomic analysis with potential implications in pathophysiology, diagnosis, prognosis, and therapy of cancer
Authors: Scatena Roberto , Bottoni Patrizia , Giardina Bruno 
Published: February 2008

AbstractThe recent development of compounds that induce cell differentiation in various types of cancer cells has enabled the molecular mechanisms governing this kind of induced cancer regression to be investigated. Moreover, this approach to investigating the pathophysiology of neoplasia represents a promising experimental model for proteomic analysis of cancer cells. Modulating neoplastic cell differentiation grade may reveal cytodifferentiation‐related protein expression changes, and doing soin vitrohas the advantage of less biological variation. Hence, this analysis brings attention to molecular targets of the so‐called differentiating factors (i.e., retinoids, hybrid polar compounds, tyrosine kinase inhibitors,etc.) as well as proteins that are frequently associated with differentiation/dedifferentiation processes. Thein vitrostudy of these proteins and of their pathogenetic roles in cancer may ultimately result in the discovery of cancer biomarkers with diagnostic, prognostic, and therapeutic applications.
Exciting prospects for solids: Exact‐exchange based functionals meet quasiparticle energy calculations
Authors: Rinke Patrick , Qteish Abdallah , Neugebauer Jörg , Scheffler Matthias 
Published: February 2008

AbstractFocussing on spectroscopic aspects of semiconductors and insulators we will illustrate how quasiparticle energy calculations in the G0W0 approximation can be successfully combined with density‐functional theory calculations in the exact‐ exchange optimised effective potential approach (OEPx) to achieve a first principles description of the electronic structure that overcomes the limitations of local‐ or gradient‐corrected DFT functionals (LDA and GGA). (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structure of gallium‐doped mayenite and its reduction behaviour
Authors: Palacios Luis , Bruque Sebastián , Aranda Miguel A. G. 
Published: February 2008

AbstractThe isovalent Al/Ga substitution in mayenite has been studied by preparing the (Ca12Al14–x Gax O32)O1□5 series. Single phase compounds can be prepared up to x = 1 and the structure of this compound has been studied by joint Rietveld analysis of neutron and X‐ray powder diffraction data. The results showed that gallium substitutes aluminium, which provokes the expansion of the unit cell, as expected. (Ca12Al13GaO32)O1□5 has been treated at high temperature under strong reducing conditions to prepare an electride derivative. Unfortunately, instead the reduction leaving electrons into the mayenite cages, the Ga‐doped mayenite undergoes decomposition. The initial compound transforms to Ca3Al2O6, (Ca12Al14O32)O1□5 and amorphous Ga metal, which is likely deposited on the mayenite crystal surfaces. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structure–charge mobility relation for hexabenzocoronene derivatives
Authors: Andrienko Denis , Kirkpatrick James , Marcon Valentina , Nelson Jenny , Kremer Kurt 
Published: February 2008

AbstractCharge mobilities of several derivatives of discotic liquid crystals have been determined by combining three methods into one scheme: (i) quantum chemical methods for the calculation of molecular electronic structures and reorganization energies (ii) molecular dynamics for simulation of the relative positions and orientations of molecules in a columnar mesophase, and (iii) kinetic Monte Carlo simulations and Master Equation approach to simulate charge transport. Applying this scheme to differently substituted hexabenzocoronene derivatives we reproduce the trends and magnitudes of mobilities as measured by pulse‐radiolysis time‐resolved microwave conductivity (PR‐TRMC) and connect mobility directly to the microscopic morphology of the columns. Our study also shows that it is possible to understand and reproduce experimental charge transport parameters, and, in some cases, accurately predict them. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stability analysis of graphene nanoribbons by molecular dynamics simulations
Authors: Dugan N. , Erkoç S¸. 
Published: February 2008

AbstractIn this work, stability of graphene nanoribbons are investigated using molecular dynamics. Simulations include heating armchair and zigzag‐edged nanoribbons of widths varying between one and nine hexagonal rings until the bonds between carbon atoms start to break. Breaking temperatures and binding energies per atom for different widths are presented for both armchair and zigzag‐edged cases. A nontrivial relation between stability and width is observed and discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A study of flexoelectric coupling associated internal electric field and stress in thin film ferroelectrics
Authors: Ma Wenhui 
Published: February 2008

AbstractBy discussions in the framework of tensor representations and phenomenological theory, general piezoelectricity equations that incorporate direct and inverse flexoelectric effects were analyzed and interlink between direct and inverse flexoelectricity discovered. Due to flexoelectric coupling, mechanical strain gradient is equivalent to internal electric field. In ferroelectrics above the Curie temperature, it was shown theoretically that strain gradient associated electric field leads to non‐zero polarization without external electric field. It was also shown theoretically that polarization (or electric field) gradient is an extra source of internal stress. Magnitudes of flexoelectricity associated internal electric field and stress were analyzed for heteroepitaxial thin films of barium strontium titanate. Flexoelectric coupling is expected to intensify with reducing lateral dimensions and thickness and get large enough at nanoscale to modify ferroelectric phase transitions and functional response. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)