bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of Sox8, Sf1, Gata4, Wt1, Dax1, and Fog2 in the mouse ovarian follicle: Implications for the regulation of Amh expression
Authors: Salmon Nicholas A. , Handyside Alan H. , Joyce Ieuan M. 
Published: December 2004

AbstractAnti‐Müllerian hormone (Amh) is expressed in the granulosa cells of growing and preovulatory follicles in the mouse ovary where it acts to decrease responsiveness to follicle stimulating hormone (FSH) and plays a role in inhibiting primordial follicle recruitment. Recently, co‐culture of isolated oocytes and granulosa cells has demonstrated that Amh expression is up‐regulated in the presence of oocytes and, at preantral stages, this effect is dependent upon close contact. In Sertoli cells, Amh expression is regulated by several transcription factors including SOX9, SF1, GATA4, WT1, and DAX1, which, with the exception of SOX9, are also expressed in granulosa cells where GATA4 is known to up‐regulate Amh expression antagonised by FOG2. Here, we demonstrate that Sox8, which is closely related to Sox9 and encodes the protein SOX8 which can transactivate Amh, is expressed in the postnatal mouse ovarian follicle but is not co‐expressed with Amh in the granulosa cells of preantral follicles. Sox8 expression was found only in the oocytes of preantral follicles and in the oocytes, cumulus cells, and mural granulosa cells of preovulatory follicles. Also, increased expression of Amh in granulosa cells co‐cultured with oocytes was not associated with increased mRNA levels of the transcription factors Sf1, Gata4, Wt1, Dax1, or Fog2. These findings reveal Sox8 expression in the ovarian follicle and show that oocyte regulation of Amh expression is not due to oocyte regulation of Sf1, Gata4, Wt1, Dax1, or Fog2 expression in granulosa cells. Mol. Reprod. Dev. 70: 271–277, 2005. © 2005 Wiley‐Liss, Inc.
Development of cloned pig embryos by nuclear transfer following different activation treatments
Authors: Kim Yang‐Sil , Lee Sung‐Lim , Ock Sun‐A , Balasubramanian S. , Choe Sang‐Young , Rho Gyu‐Jin 
Published: December 2004

AbstractThis study compared the effects of activation treatments on the development and ploidy of nuclear transferred (NT) pig embryos. After in vitro maturation of oocytes collected from the slaughterhouse, oocytes were enucleated and reconstructed by transfer of donor cells and fusion with three DC pulses (1.4 kV/cm, 20 μsec). Oocytes were pulsed thrice electrically with 1.4 kV/cm for 20 μsec and NT eggs were divided into three treatment groups: Group 1 (no further treatment), Group 2 (10 μg/mL cycloheximide [CHX], 3 hr), and Group 3 (1.9 mM 6‐dimethylaminopurine [DMAP], 3 hr). All the eggs were cultured in sets of 30 in 60 μL drops of NCSU‐23 supplemented with 4 mg/mL fatty acid free BSA, and compared for the rates of development and ploidy. The rates of cleavage, development, and total cell number of parthenotes in Group 3 were significantly (P < 0.05) higher than those in Groups 1 and 2. Cleavage rates of NT embryos in Group 1 were significantly (P < 0.05) lower than those in Groups 2 and 3 (73% vs. 81% and 82%, respectively). Development into blastocyst stage and total cell number of NT embryos in Group 3 were significantly (P < 0.05) higher than those in Groups 1 and 2. Although the embryos in Group 3 had higher development, ∼58% of NT embryos evaluated were abnormal ploidy (6% haploidy, 9% polyploidy, and 42% mixoploid). The results suggested that although DMAP enhanced development and higher cell number, due attention should be paid to abnormal ploidy in pig NT embryos. Mol. Reprod. Dev. 70: 308–313, 2005. © 2005 Wiley‐Liss, Inc.
Indomethacin preserves muscle mass and reduces levels of E3 ligases and TNF receptor type 1 in the gastrocnemius muscle of tumor‐bearing mice
Authors: Hitt Andrew , Graves Erin , McCarthy Donna O. 
Published: December 2004

AbstractTumor‐induced skeletal muscle wasting involves tumor necrosis factor (TNF) and the ubiquitin‐proteasome pathway of muscle protein degradation. In this study, growth of the colon‐26 adenocarcinoma in mice was associated with diminished gastrocnemius muscle mass and increased muscle levels of actin, ubiquitin‐conjugated proteins, free ubiquitin, E3 ubiquitin ligases, and the type 1 TNF receptor (TNFR1). Indomethacin at 1 or 5 mg/kg/day reduced tumor growth and muscle levels of TNFR1. However, only the 5 mg dose of indomethacin reduced muscle wasting and muscle levels of the E3 ligases and actin. These data suggest that the beneficial effects of indomethacin in the treatment of tumor‐induced skeletal muscle wasting may involve inhibition of TNF‐ and ubiquitin‐mediated pathways of muscle protein degradation. These data also demonstrate that E3 ligases, which are involved in disuse atrophy, also are associated with tumor‐induced skeletal muscle wasting. © 2004 Wiley Periodicals, Inc. Res Nurs Health 28:56–66, 2005
Error estimations for some meshless boundary interpolation methods
Authors: Gáspár Csaba 
Published: December 2004

AbstractMeshless methods have become quite popular in numerical treatment of partial differential equations because of their simplicity and the fact that they require neither domain nor boundary mesh. In general, however, they convert the original problem to a highly ill‐conditioned linear system of algebraic equations with a dense matrix. Recently, a special technique has been proposed which circumvents this computational difficulty. This method, called Direct Multi‐Elliptic Interpolation Method, is based on a scattered data interpolation which defines the interpolation function as a solution of a higher order multi‐elliptic equation. Here the boundary version of this meshless method which is based on a multi‐elliptic boundary interpolation is considered. Error estimations are derived justifying the interpolation function to be a good approximation of the solution of the original boundary value problem as well. At the same time, the problem of large, dense and ill‐conditioned matrices as well as the mesh generation are completely avoided. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On The Atmospheric Boundary Layer Flow Modelling
Authors: Sládek I. , Kozel K. , Jaňour Z. 
Published: December 2004

AbstractThe paper presents a mathematical and numerical investigation of the flow in the atmospheric boundary layer (ABL) over complex topography. The flow is supposed to be viscous, incompressible, turbulent and stationary. Two different mathematical–numerical approaches are briefly mentioned. Both models have been used to simulate a flow and pollution dispersion over a complex surface coal field in the North Bohemia which is supposed to be partially covered by a high forest stand. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
More About Geršgorin‐type theorems
Authors: Cvetković Ljiljana , Kostić Vladimir 
Published: December 2004

AbstractIn the recent book of R.S. Varga, [3], one of two main recurring themes is that a nonsingular theorem for matrices gives rise to an equivalent eigenvalue inclusion set in the complex plane, and conversely. If such nonsingularity result can be extended via irreducibility, usually this can be used for obtaining more information about the boundary of the corresponding eigenvalue inclusion set. Here we will start with one of Geršgorin‐type theorem for eigenvalue inclusion, given in [1], (for which exists corresponding equivalent statement about nonsingularity of a particular class of matrices) and use it for proving necessary conditions for an eigenvalue to lie on the boundary of localization area. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical Treatment of Catenary Systems
Authors: Teichelmann Gunnar 
Published: December 2004

AbstractSimulation is of great importance in the development of railway cable systems. Mathematical models and numerical methods for the computation of both static equilibria and dynamic oscillations of railroad catenaries are being derived. These cable systems form a complex network of string and beam elements and lead to coupled partial differential equations in space and time where constraints and corresponding Lagrange multipliers express the interaction between carrier, contact wire, and pantograph head. For computing static equilibria, two different algorithms are presented, while the dynamic case is treated by a finite element method in space, combined with stabilized time integration of the resulting differential algebraic system. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Least‐Squares Formulation for the Shallow Water Equations with Small Viscosity
Authors: Danisch Garvin 
Published: December 2004

AbstractA least‐squares finite element method for the shallow water equations with viscosity parameter μ > 0 is proposed and studied. The shallow water equations are reformulated as a first order system by adding a new variable for the velocity flux. The reformulated first order system is combined with a characteristic‐based time discretization and a least squares approach. For the correct boundary treatment in the limit case μ → 0, a trace theorem is presented. For the numerical computation of the velocity, the finite element spaces introduced recently by Mardal, Tai and Winther (SIAM Journal on Numerical Analysis 40, pp. 1605–1631) are used. The degrees of freedom in these spaces can be identified with the normal and tangential components, respectively. Numerical results for some test examples are shown. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On‐line mixing during injection and simultaneous curing in liquid composite molding processes
Authors: Devillard Mathieu , Laut Antoine , Advani Suresh G. 
Published: December 2004

AbstractLiquid composite molding (LCM) processes such as resin transfer molding (RTM) and vacuum assisted RTM (VARTM) are used to manufacture high quality and net‐shape fiber reinforced composite parts. All LCM processes impregnate fiber preforms packed in a mold cavity with a thermoset resin. After the preform is fully saturated, the injection is discontinued but the resin continues to cure. Once the curing step is complete, the part is de‐molded. The resin has to be mixed with a curing agent to cure. Typically, the resin and the curing agent are mixed together in a pressure pot before the injection. This has several disadvantages, such as storage of large amounts of hazardous polymerizing resin, wastage, and cleaning of cured resin from the injection line. This paper proposes the implementation and calibration of an alternative to this technique. The approach is to mix the curing agent with the resin as the resin enters the mold through a separate system featuring two feed‐lines. Such a system will enable one to maintain a uniform gel time throughout the part by varying the mixing ratio of resin and the catalyst during the injection. An experimental study of such on‐line mixing to obtain simultaneous curing and to reduce the overall curing time is conducted and presented in this paper. Implementation of a control scheme that varies the curing agent during injection and its effect on cure time is benchmarked with the process in which the percentage of curing agent is held constant. The gel time for the fabricated parts was reduced by 20–25% by continuously varying the percentage of curing agent during injection. POLYM. COMPOS., 26:74–83, 2005. © 2004 Society of Plastics Engineers
Salicylic acid modified high performance epoxy matrices
Authors: Ibrahim A. Mahammad , Seferis James C. 
Published: December 2004

AbstractThis study focuses on the processing‐structure‐property relations for salicylic acid modified high performance epoxy matrix systems for carbon fiber composites. Differential scanning calorimetry and dynamic mechanical data have shown that as the concentration of salicylic acid increases, the degree of cure first increases, reaches a maximum, and then decreases steadily. Analysis of the results indicated that small amounts of salicyclic acid accelerates the amine‐epoxide reactions resulting into crosslinked networks with increased degree of cure; increasing amounts, however, give rise to networks with reduced crosslinking by reducing the net available diaminodiphenyl sulfone (DDS) content in the system by a reaction of the DDS with salicylic acid. Overall, this study has demonstrated that salicyclic acid modification offers the potential for monitoring and controlling amine‐epoxide reactions that may influence the application and usage of epoxy matrices in composite systems.
Optimization of polyester sheet molding compound. Part II: Theoretical modeling
Authors: Fan J. D. , Lee L. James 
Published: December 2004

AbstractA mechanistic kinetic and heat transfer model is used to describe the cure of sheet molding compounds (SMC). Kinetic parameters such as rate constant of initiator decomposition and rate constant of propagation are estimated from the induction time and the time to reach the peak exotherm of isothermal reaction curves measured by the differential scanning calorimetry (DSC). Temperature and conversion profiles inside plate sections of SMC parts during molding are measured. The predicted results compare well with the experimental data except the limiting conversion. A set of predictive parameters are proposed from this model as guidelines for the optimal molding of SMC. Several moldability diagrams are also constructed which can be easily used to design the optimum SMC recipe for a given processing condition.
The effect of the applied field on the electrical properties of metal polymer composites
Authors: Nobile M. R. , Nicodemo L. , Nicolais L. , Egiziano L. , Lupo G. , Tucci V. 
Published: December 2004

AbstractThe effect of filler content and applied electrical field on the electrical resistivity of poly(methyl methacrylate) (PMMA) filled with aluminum particles was investigated. The resistivity of such composite suddenly decreases by several orders of magnitude at a critical volume concentration ϕc. In addition, for filler contents lower than ϕc, the PMMA/Al composite undergoes a transition from a high to a low resistance material in correspondence of a critical value of the external applied electrical field. This value has been related to thermal breakdown occurring in the regions between conductive particles. Moreover, the permittivity spectrum as a function of frequency is reported for composites of several filler contents, and the Lal and Parshad law was used to correlate the experimental data.
A boundary element analysis of flow in sheet molding compound
Authors: Barone M. R. , Osswald T. A. 
Published: December 2004

AbstractA new boundary element method has been developed for analyzing the flow of sheet molding compound (SMC) during compression molding. The boundary element equations can be used to determine the velocities on the perimeter of the charge. Successive flow front configurations are then generated by a simple explicit updating procedure. This approach was used to predict the flow front progression for elliptical, rectangular, and L‐shaped charges. Comparisons with experimental data for elliptical and rectangular charges were encouraging. The fact that it was possible to obtain reasonable agreement for charges with different shapes and thicknesses lends support to the underlying flow model. Furthermore, valuable insight regarding knit line formation was acquired by analyzing the L‐shaped charge. Results from the boundary element analysis showed that the initial thickness of the charge has a pronounced effect on knit line development. Even though there is considerable industrial experience in making SMC parts, the important role of charge thickness on knit line formation appears to have been largely overlooked. Prior analyses gave no indication of this effect because they were based on lubrication models that were independent of charge thickness.
Effect of the textural characteristics of the new silicas on the dynamic properties of styrene‐butadiene rubber (SBR) vulcanizates
Authors: Rueda L. Ibarra , Hernandez L. González , Anton C. Chamorro 
Published: December 2004

AbstractIt is possible to obtain silicas with different textural characteristics from natural silicates by means of an acid treatment, where the textural characteristics of the new silicas obtained are greatly influenced by the reaction conditions. The mechanodynamical behavior of compounds filled with these silicas and based on Styrenebutadiene rubber (SBR) matrices was studied. The influence of the textural characteristics on dynamic properties is explained in terms of the stiffness, porosity, and structure of the silica particles. Silicas obtained at drastic reaction conditions yield compounds with a higher storage modulus, E′, at low strain amplitudes, but with a lower storage modulus at high strain amplitudes. The maximum loss factor, tanδ, is a function of the silica external surface area.
A note on polymeric inner‐layered single fiber interfacial strength determination
Authors: Davé Raju , Lorenzo Luis 
Published: December 2004

AbstractThe role of inner‐layer (interphase) in fiber‐reinforced composites is often assessed by measuring the interfacial shear strength of single fibers embedded in matrix blocks. Interfacial shear strength is calculated using simple shear lag analyses (Kelly and Tyson model). This paper shows that application of Kelly and Tyson's equation may result in gross overprediction of interfacial shear strengths if the thickness of the inner‐layer is not negligible in comparison with the fiber diameter.
Interfacial shear strength studies using the single‐filament‐composite test. I: Experiments on graphite fibers in epoxy
Authors: Netravali A. N. , Henstenburg R. B. , Phoenix S. L. , Schwartz P. 
Published: December 2004

AbstractThe failure of the interface in a carbon fiber‐epoxy system was studied for six different epoxy blends using the single‐filament‐composite technique. The blends were formulated to yield a wide range of stiffnesses, and their effect on interfacial failure was examined. Specimens were made from Hercules IM6‐G carbon fiber and the different blends of epoxy, and then strained to obtain a distribution of fiber fragment lengths. Birefringence patterns near the fiber breaks were observed and recorded. Some of the specimens were strained until they failed and the resulting fracture surfaces were observed under a scanning electron microscope to determine fracture patterns and the existence of debonding. The fragment length distributions were interpreted using a Monte‐Carlo simulation of a Poisson/Weibull model for fiber strength and flaw occurrence. The results were used to calculate an effective interfacial shear strength. From this analysis we conclude that one cannot accurately predict the interfacial properties of a composite based solely upon conventional single fiber and bulk matrix properties. Local matrix properties and fiber/matrix interactions, on a microscale, play a key role in composite strength.
Dilatancy of concentrated suspensions with Newtonian matrices
Authors: Yilmazer Ulku , Kalyon Dilhan M. 
Published: December 2004

AbstractSuspensions filled close to their maximum packing fraction present special challenges in their processing and in their rheological characterization. In this report, the literature in the area of dilatancy of concentrated suspensions is reviewed. Furthermore, the shear viscosity of a Newtonian polymeric liquid filled with 60 vol. percent of ammonium sulfate has been investigated. Both capillary and parallel disk torsional flows, were employed, spanning three decades in shear stress. Upon correction for slip, the suspension exhibited shear thinning at low shear stresses and shear thickening at higher shear stresses. Above a critical wall shear stress, the shear viscosity of the suspension increased unboundedly and the flow became pluglike with apparent slip at the wall. These findings have important ramifications in the processing of composites from such concentrated suspensions.
Issues in diaphragm forming of continuous fiber reinforced thermoplastic composites
Authors: O'Brádaigh Conchúr M. , Pipes R. Byron , Mallon Patrick J. 
Published: December 2004

AbstractA literature survey is presented on sheet‐forming methods and mechanisms for continuous fiber reinforced thermoplastics. The diaphragm forming process is shown to be one of the more promising fabrication routes for complex‐curvature structures. The primary deformation mechanisms involved in the sheet‐forming processes are identified and discussed. Earlier approaches to develop mathematical models either have been kinematically based or have treated only one of the primary deformation mechanisms. A promising constitutive model for the highly anisotropic behavior of the composite at forming temperature is examined. The composite sheet is assumed to behave as a transversely isotropic Newtonian fluid that is both incompressible and inextensible in the fiber direction. The second section of the paper treats the experimental development of the polymeric diaphragm forming process for thermoplastic composites. The viscoelastic properties of the diaphragm material are characterized by dynamic mechanical analysis. The rate sensitivity of the phenomenon of shear‐buckling during forming of certain cross‐ply and quasi‐isotropic composite laminates is investigated, using a shallow female mold. Finally, the interface condition between the diaphragm and the composite during forming is examined.
The electromagnetic interference shielding of polypyrrole impregnated conducting polymer composites
Authors: Ruckenstein E. , Park J. S. 
Published: December 2004

AbstractA lightweight conducting polymer composite was prepared by the incorporation of conducting polypyrrole in the pores of a host polymer to form a conductive network. The inclusion of polypyrrole in a porous cross‐linked polystyrene host polymer, prepared by the concentrated emulsion polymerization method, was carried out by imbibing the host polymer with a pyrrole solution (or oxidant solution), partially drying the saturated host polymer, and imbibing it again with the oxidant solution (or pyrrole solution) for 2 h. The conductivity of the polymer composite is as high as 0.5 S/cm and the shielding effectiveness of the composite reaches 26 dB in the frequency range from 1.0 to 2.0 GHz.
Instrumented thermoforming of advanced thermoplastic composites. II: Dynamics of double curvature part formation and structure development from PEEK/carbon fiber prepreg tapes
Authors: Cakmak M. , Dutta A. 
Published: December 2004

AbstractPoly(ether ether ketone) (PEEK) carbon fiber prepreg tapes (APC‐2) have been thermoformed into a hemispherical double curvature part under a variety of processing conditions. Conventional matched die molding using aluminum molds (at 200°C) were not successful in thermoforming acceptable parts. Parts with severe wrinkling and folding were obtained. A novel three‐piece (steel) mold with built‐in sheet clamping arrangement was, therefore, designed and fabricated. This mold was used at 400°C temperature to thermoform parts from preheated preconsolidated laminates. More interestingly, using the above conditions, 8‐ and 16‐ply unconsolidated laminates could be directly thermoformed into parts that were microstructurally sound and exhibited good shape conformity. Results suggest a cycle time of 15 min, with scope for further reduction, if mold cooling is employed. Notwithstanding the simplicity of the thermoforming process, such a short cycle time compares quite favorably with cycle times of several hours for conventional thermosetting resin based composites.