bluuebunny/crossref_metadata_2025_split huggingface dataset:
Performance and Durability of Membrane Electrode Assemblies Based on Radiation‐Grafted FEP‐g‐Polystyrene Membranes
Authors: Gubler L. , Kuhn H. , Schmidt T.J. , Scherer G.G. , Brack H.‐P. , Simbeck K. 
Published: July 2004

AbstractMembrane electrode assemblies (MEAs) based on radiation‐grafted proton exchange membranes developed at PSI have shown encouraging performance in the past in hydrogen and methanol fuelled polymer electrolyte fuel cells. In this study, the effect of the pre‐treatment of crosslinked radiation‐grafted FEP membranes prior to lamination with the electrodes on the performance of the MEAs was investigated. Two approaches were assessed separately and in combination: (1) the impregnation of the radiation‐grafted membranes with solubilised Nafion®, and (2) the use of a swollen vs. dry membrane. It is found that the combination of coating the membrane with Nafion® ionomer and hot‐pressing the MEA with the membrane in the wet state produce the best single cell performance. In the second part of the study, the durability of an MEA, based on a radiation‐grafted FEP membrane, was investigated. The performance was stable for 4,000 h at a cell temperature of 80 °C. Then, a notable degradation of the membrane, as well as the electrode material, started to occur as a consequence of either controlled or uncontrolled start‐stop cycles of the cell. It is assumed that particular conditions, to which the cell is subjected during such an event, strongly accelerate materials degradation, which leads to the premature failure of the MEA.
Bilayer Anodes for Improved Reformate Tolerance of PEM Fuel Cells
Authors: Janssen G.J.M. , de Heer M.P. , Papageorgopoulos D.C. 
Published: July 2004

AbstractThe concept of bilayer anodes for improved reformate tolerance was analysed using model calculations. It was found that for a bilayer anode to give good results the catalyst in the layer adjacent to the backing should enable CO oxidation at low potentials and have a relatively low rate of H2 oxidation. The catalyst in the second layer should enable fast H2 oxidation, and have limited CO adsorption. Experimental results are presented showing that the bilayer anode works especially well with reformate gas. It was found that the water gas shift equilibrium plays an important role in the mechanism for reformate tolerance. The implementation of the bilayer concept seems to be very useful in optimising both CO and CO2 tolerance of PEMFCs, including at high fuel utilisation.
Fuel Cells for People
Authors: Cropper M. 
Published: July 2004

AbstractPortable power promises to be the first truly commercial market for fuel cell technology. In this keynote presentation, which is accompanied by an up‐to‐date survey published on 1 July 2003 at www.fuelcelltoday.com/surveys, we review the activity that has so far taken place worldwide in this exciting sector of the fuel cell industry. Features include a review of the number of systems so far built, the different fuel cell types under development, fuel choice and region of development. In addition, this article will also discuss the various potential markets for portable fuel cells, and the some of the issues that are associated with them.
Characterising PEM Fuel Cell Performance Using a Current Distribution Measurement in Comparison with a CFD Model
Authors: Hakenjos A. , Tüber K. , Schumacher J.O. , Hebling C. 
Published: July 2004

AbstractThe characterisation of a proton exchange membrane (PEM) fuel cell with a straight channel flow field design is performed. Spatially resolved current distribution measurements, at different air flow rates, are compared to numerical simulation results. The numerical model is validated by agreement of the measured and simulated current distribution.The test cell is segmented. It is operated at steady state conditions and the gas flow rates and cell temperature are controlled. The numerical simulation is realised with a PEM fuel cell model based on FLUENT™ computational fluid dynamics (CFD) software. It accounts for mass transport in the gaseous phase, heat transfer, electrical potential field and the electrochemical reaction. It provides three‐dimensional distributions of, e.g., current densities, reactant concentrations and temperature.
The impact of time duration between trades on the price of treasury note futures contracts
Authors: Holder Mark E. , Qi Min , Sinha Amit K. 
Published: July 2004

AbstractRecent research in finance has indicated that the institutional structure in which financial asset prices are determined can have a nontrivial impact on pricing. This report examines transaction level data for Treasury Note futures contracts traded at the Chicago Board of Trade (CBOT) to identify institutional, or market microstructure, impacts on the pricing of these contracts. Relatively few articles have conducted empirical research on the microstructure of U.S. futures trading due to the limited availability of comprehensive transaction level data from the futures exchanges. This report uses the CBOT's Computerized Trade Reconstruction database, a comprehensive transaction level dataset, to identify the price impact of the time duration between trades in a manner analogous to that of A. Dufour and R. F. Engle (2000). Unique differences from prior research include the application to futures contracts with their relative higher frequency of trading, as well as the investigation of the price impact of the number of active traders present on the trading floor and the trading volume. Subsequent price and sign of trade significantly relate to the time duration between trades, the number of floor brokers, and the trading volume. © 2004 Wiley Periodicals, Inc. Jrl. Fut Mark 24:965–980, 2004
Sonographically guided injection of anesthetic for iliopsoas tendinopathy after total hip arthroplasty
Authors: Wank Ross , Miller Theodore T. , Shapiro Jeffrey F. 
Published: July 2004

AbstractWe report 2 patients who developed pain in the region of the iliopsoas tendon after undergoing total hip arthroplasty. The pain was temporarily relieved by sonographically guided injection of steroid and anesthetic and was subsequently treated by surgical release of the tendon. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:354–357, 2004
Value of sonography in the diagnosis of abnormal vaginal bleeding
Authors: Dubinsky Theodore J. 
Published: July 2004

AbstractAbnormal vaginal bleeding is one of the most common presenting complaints in women of any age seeking gynecologic health care. Two of the most frequently used diagnostic tests to investigate the cause of the bleeding are endometrial biopsy and transvaginal sonography. The most worrisome cause of abnormal bleeding is endometrial carcinoma, yet benign etiologies are far more prevalent, including fibroids, polyps, and endometrial atrophy. Endometrial biopsy and transvaginal sonography have equal sensitivities for carcinoma, but sonography is far more effective in diagnosing benign disease. This article reviews the state‐of‐the‐art in the diagnostic evaluation of abnormal vaginal bleeding and analyzes the data, with emphasis on the prevalence of benign and malignant disease as the basis for determining whether sonography or biopsy is more cost‐effective in evaluating women with abnormal vaginal bleeding. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:348–353, 2004
Sonographic guidance for electron boost planning after breast‐conserving surgery
Authors: Warszawski Antje , Baumann Rolf , Karstens Johann H. 
Published: July 2004

AbstractPurposeThis study was conducted to determine the feasibility of using sonography for electron boost planning in breast cancer treatment and to define the factors that influence the accuracy and reproducibility of this technique.Patients and MethodsSeventy‐seven patients underwent 102 sonographic examinations after breast‐conserving surgery and before and after radiotherapy. The size of the electron boost field was defined by measuring the postoperative cavity. Reproducibility of the sonographic findings was investigated in 25 of the patients who were examined before and after radiotherapy (at a total dose of 46–50.4 Gy). Depth (distance from the skin surface to the posterior aspect of the postoperative cavity) was measured, and sonographic appearance of the postoperative cavity was evaluated. Type of surgical procedure, time elapsed since surgery, use of systemic therapy, menopausal status, breast size, and radiation dose were investigated for their influence on sonographic appearance and visualization of the postoperative cavity.ResultsThe postoperative cavity was well visualized in 78% of patients and visualized with some difficulty in 22%. In all but 5 patients, it was hypoechoic and inhomogeneous. The mean depth of the postoperative cavity after radiotherapy was 27 ± 4 mm. Smaller breast (p < 0.001) and younger age (p < 0.05) were associated with decreased visibility of the postoperative cavity. Sonographic appearance was the same before and after radiotherapy, but the mean difference in postoperative cavity depth between the 2 measurements was 2 mm (range, 0–4 mm). In 43/77 (56%) of the patients, changes in electron energy or in field size were required after sonographic measurement.ConclusionSonography is a useful and reproducible means of electron boost planning, helping to avoid underdosage of the postoperative cavity and overdosage of normal tissue. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:333–337, 2004
Role of sonography in diagnosing and staging invasive lobular carcinoma
Authors: Selinko Veronica L. , Middleton Lavinia P. , Dempsey Peter J. 
Published: July 2004

AbstractPurposeThe goal of this study was to compare the sensitivity of sonography with that of mammography in the detection of invasive lobular carcinoma (ILC), to identify ILC's typical imaging characteristics, and to further show the important role of ultrasound in the staging and treatment planning of this elusive tumor.MethodsWe identified all patients with ILC seen at our institution from 1998 through 2001; 62 had pathologically proven pure ILC. We retrospectively reviewed and analyzed the sonographic appearances in correlation with mammographic, pathologic, and clinical findings. We reviewed the results of sonographic examinations of the nodal basins and fine‐needle aspiration (FNA) of suspicious nodes and correlated them with initial clinical and final pathologic staging. We noted all cases of multicentricity or multifocality and analyzed the relative sensitivity of mammography and sonography according to tumor size.ResultsSonography had a sensitivity of 98% versus 65% for mammography. The most common mammographic pattern was a spiculated mass or architectural distortion (39%). On sonography the most common pattern was a hypoechoic mass with (58%) or without (27%) shadowing. An infiltrative pattern was observed in 13% of the cases. Ultrasound‐guided FNA confirmed disease was present in the axillary lymph nodes in 21% of the patients, and sonographic examination of the nodal basins resulted in a change of clinical staging from N0 to N1 in 75% and from N1 to N0 in 30% of the cases. Multicentricity/multifocality was identified sonographically and proved by FNA in 21% of patients.ConclusionsSonography has a much higher sensitivity than mammography in detecting ILC and therefore is an important adjunctive tool in the diagnosis of this form of cancer. Routine examination of node‐bearing areas in patients with ILC proved useful in refining the disease staging. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:323–332, 2004
P26h and dicarbonyl/L‐xylulose reductase are two distinct proteins present in the hamster epididymis
Authors: St‐cyr Antoine , Légaré Christine , Frenette Gilles , Gaudreault Christian , Sullivan Robert 
Published: July 2004

AbstractWe have previously identified a 34 kDa protein (P34H) on the human sperm surface covering the acrosome. Using the hamster, we have also described a sperm protein, P26h, which is acquired by spermatozoa during epididymal transit. Both P34H and P26h belong to the carbonyl reductase family. Using molecular tools derived from P34H, we searched in the hamster epididymis for another protein related to the human sperm protein. Cloning and sequencing of P31h cDNA revealed 100% homology with the kidney DCXR (Dicarbonyl/L‐Xylulose reductase). Northern Blot experiments revealed a single mRNA that was more expressed in the caput than in the corpus and cauda segment of adult epididymides. In situ hybridization was performed on sexually mature hamsters showing that the mRNA was localized in the principal cells throughout the epididymis. Using an anti‐P34H antibody we have identified a P34H related protein named P31h (for 31 kDa). This protein showed 2D‐electrophoretic behavior different from P26h and was detectable all along the epididymis (caput, corpus, and cauda) by Western Blot analysis. Immunohistochemistry techniques showed that P31h was localized in the perinuclear region of the principal cells of the epididymal epithelium within the three sections, both in sexually mature and immature animals. Results are discussed with regards to the potential function of DCXR in the epididymis. Mol. Reprod. Dev. 69: 137–145, 2004. © 2004 Wiley‐Liss, Inc.
A unique mechanism for cyclic adenosine 3′,5′‐monophosphate‐induced increase of 32‐kDa tyrosine‐phosphorylated protein in boar spermatozoa
Authors: Harayama Hiroshi , Sasaki Kiyomi , Miyake Masashi 
Published: July 2004

AbstractA cAMP‐induced increase of tyrosine‐phosphorylated proteins is involved in the expression of fertilizing ability in mammalian spermatozoa. We (Harayama, 2003: J Androl 24:831–842) reported that incubation of boar spermatozoa with a cell‐permeable cAMP analog (cBiMPS) increased a 32‐kDa tyrosine‐phosphorylated protein (TyrP32). The purpose of this study is to characterize the signaling cascades that regulate the cAMP‐induced increase of TyrP32. We examined effects of tyrosine kinase inhibitor (lavendustin A), tyrosine phosphatase inhibitor (Na3VO4), cell‐permeable calcium chelator (BAPTA‐AM), and cholesterol acceptor (methyl‐β‐cyclodextrin: MBC) on the increase of TyrP32 and the change and loss of acrosomes in boar spermatozoa. The spermatozoa were used for detection of tyrosine‐phosphorylated proteins by Western blotting and indirect immunofluorescence and for examination of acrosomal integrity by Giemsa staining. At least eight tyrosine‐phosphorylated proteins including TyrP32 exhibited the cAMP‐dependent increase during incubation with cBiMPS. In many proteins of them, this increase was reduced by lavendustin A but was enhanced by Na3VO4. In contrast, the cAMP‐induced increase of TyrP32 was abolished by Na3VO4 but was hardly affected by lavendustin A. Giemsa staining showed that the increase of spermatozoa with weakly Giemsa‐stained acrosomes (severely damaged acrosomes) or without acrosomes was correlative to the cAMP‐induced increase of TyrP32. Moreover, the lack of calcium chloride in the incubation medium or pretreatment of spermatozoa with BAPTA‐AM blocked the change and loss of acrosomes and the increase of TyrP32, suggesting these events are dependent on the extracellular and intracellular calcium. On the other hand, incubation of spermatozoa with MBC in the absence of cBiMPS could mimic the change and loss of acrosomes and increase of TyrP32 without increase of other tyrosine‐phosphorylated proteins. Based on these results, we conclude that the cAMP‐induced increase of TyrP32 is regulated by a unique mechanism that may be linked to the calcium‐dependent change and loss of acrosomes. Mol. Reprod. Dev. 69: 194–204, 2004. © 2004 Wiley‐Liss, Inc.
Origin of the murine implantation serine proteinase subfamily
Authors: O'Sullivan Colleen M. , Tang Lin , Xu Hui , Liu Shiying , Rancourt Derrick E. 
Published: July 2004

AbstractThe S1 serine protease family is one of the largest gene families known. Within this family there are several subfamilies that have been grouped together as a result of sequence comparisons and substrate identification. The grouping of related genes allows for the speculation of function for newly found members by comparison and for novel subfamilies by contrast. Analysis of the evolutionary patterns of genes indicates whether or not orthologs are likely to be identified in other species as well as potentially indicating that hypothesized orthologs are in fact not. Looking at subtle differences between subfamily members can reveal intricacies about function and expression. Previously, we have described genes encoding two novel serine proteinases, ISP1 and ISP2, which are most closely related to tryptases. The ISP1 gene encodes the embryo‐derived enzyme strypsin, which is necessary for blastocyst hatching and invasion in vitro. Additionally both ISP1 and ISP2 are co‐expressed in the endometrial gland during the time of hatching, suggesting that they may also both participate in zona lysis from within the uterine lumen. Here, we demonstrate that the ISPs are tandemly linked within the tryptase cluster on 17A3.3. We suggest that remarkable similarities within the 5′‐untranslated and first intron regions of ISP1 and ISP2 may explain their intimate co‐regulation in uterus. We also suggest that ISP genes have evolved through gene duplication and that the ISP1 gene has also begun to adopt an additional new function in the murine preimplantation embryo. Mol. Reprod. Dev. 69: 126–136, 2004. © 2004 Wiley‐Liss, Inc.
Changes in germinal vesicle (GV) chromatin configurations during growth and maturation of porcine oocytes
Authors: Sun Xing‐Shen , Liu Yong , Yue Kui‐Zhong , Ma Suo‐Feng , Tan Jing‐He 
Published: July 2004

AbstractChanges in germinal vesicle (GV) chromatin configurations during growth and maturation of porcine oocytes were studied using a new method that allows a clearer visualization of both nucleolus and chromatin after Hoechst staining. The GV chromatin of porcine oocytes was classified into five configurations, based on the degree of chromatin condensation, and on nucleolus and nuclear membrane disappearance. While the GV1 to 4 configurations were similar to those reported by previous studies, the GV0 configuration was distinct by the diffuse, filamentous pattern of chromatin in the whole nuclear area. Most of the oocytes were at the GV0 stage in the <1 and 1–1.9 mm follicles, but the GV0 pattern disappeared completely in the 2–2.9 and 3–6 mm follicles. As follicles grew, the number of oocytes with GV1 configurations increased and reached a maximum in the preovulatory follicles 4 hr post‐hCG injection. During maturation in vivo, the number of GV1 oocytes decreased while oocytes undergoing GVBD increased. The percentage of oocytes with GV3 and GV4 configurations was constant during oocyte growth except at the 2–2.9 mm follicle stage, but these configurations disappeared completely after hCG injection. On the contrary, the in vitro maturing oocytes showed a large proportion of GV3 and GV4 configurations. There was no significant difference in distribution of chromatin configurations between the nonatretic and atretic follicles, and between oocytes with more than two layers of cumulus cells and those with less than one layer or no cumulus cells. Overall, our results suggested that (i) the GV0 configuration in porcine oocytes corresponded to the “nonsurrounded nucleolus” pattern in mice and other species; (ii) all the oocytes were synchronized at the GV1 stage before GVBD and this pattern might, therefore, represent a nonatretic state; (iii) the GV3 and GV4 configurations might represent stages toward atresia, or transient events prior to GVBD that could be switched toward either ovulation or atresia, depending upon circumstances; (iv) the in vitro systems currently used were not favorable for oocytes to switch toward ovulation (or final maturation); (v) the number of cumulus cells was not correlated with the chromatin configuration of oocytes, indicating that the beneficial effect of cumulus cells on oocyte maturation and development may simply be attributed to their presence during in vitro culture. Mol. Reprod. Dev. 69: 228–234, 2004. © 2004 Wiley‐Liss, Inc.
Ovine ooplasm directs initial nucleolar assembly in embryos cloned from ovine, bovine, and porcine cells
Authors: Hamilton Hamish M. , Peura Teija T. , Laurincik Jozef , Walker Simon K. , Maddocks Simon , Maddox‐Hyttel Poul 
Published: July 2004

AbstractHere we present ultrastructural and immunocytochemical evidence that ovine ooplasm is directing the initial assembly of the nucleolus independent of the species of the nuclear donor. Intergeneric porcine–ovine somatic cell nuclear transfer (SCNT) and intrageneric ovine–ovine SCNT embryos were constructed and the nucleolus ultrastructure and nucleolus associated rRNA synthesis examined in 1‐, 2‐, 4‐, early 8‐, late 8‐, and 16‐cell embryos using transmission electron microscopy (TEM) and light microscopical autoradiography. In addition, immunocytochemical localization by confocal microscopy of nucleolin, a key protein involved in processing rRNA transcripts, was performed on early 8‐, late 8‐, and 16‐cell embryos for both groups of SCNT embryos. Intergeneric porcine–ovine SCNT embryos exhibited nucleolar precursor bodies (NPBs) of an ovine (ruminant) ultrastructure, but no active rRNA producing fibrillo‐granular nucleoli at any of the stages. Unusually, cytoplasmic organelles were located inside the nucleus of two porcine–ovine SCNT embryos. The ovine–ovine SCNT embryos, on the other hand, revealed fibrillo‐granular nucleoli in 16‐cell embryos. In parallel, autoradiographic labeling over the nucleoplasm, and in particular, the nulcleoli was detected. Bovine–ovine SCNT embryos at the eight‐cell stage were examined for nucleolar morphology and exhibited ruminant‐type NPBs as well as structures that appeared as fibrillar material surrounded by a rim of electron dense granules, perhaps formerly of nucleolar origin. Nucleolin was localized throughout the nucleoplasm and with particular intensity around the presumptive nucleolar compartments for all developmental stages examined in porcine–ovine and ovine–ovine SCNT embryos. In conclusion, this study suggests that factors within the ovine ooplasm are playing a role in the initial assembly of the embryonic nucleolus in intrageneric SCNT embryos. Mol. Reprod. Dev. 69: 117–125, 2004. © 2004 Wiley‐Liss, Inc.
Studies on Ca2+‐channel distribution in maturation arrested mouse oocyte
Authors: Lee Jae‐Hyun , Yoon Sook‐Young , Bae In‐Ha 
Published: July 2004

AbstractThe present study was carried out to identify the existence of voltage‐dependent Ca2+‐channels (P/Q‐, N‐, and L‐type) and their distributional differences in germinal vesicle (GV) and GV breakdown (GVBD)‐arrested mouse oocytes which includes GVBD to telophase I of meiosis I and matured oocytes (MII, metaphase of meiosis II) by using the immunocytochemical method and a confocal laser scanning microscope. (1) Comparison between follicular oocytes (GV) and GV‐arrested oocytes after 17 hr of in vitro culture. In follicular oocytes, P/Q‐, N‐, L (anti‐α1C anti‐α1D)‐type Ca2+‐channels showed both localized and uniform staining. In contrast, GV‐arrested oocytes, after in vitro culture for 17 hr, showed no presence of Ca2+‐channels in most oocytes. (2) Comparison between GVBD oocytes after culture in vitro for 3 hr and GVBD‐arrested oocytes after culture in vitro for 17 hr. In GVBD oocytes, P/Q‐, N‐, L (anti‐1C, anti‐α1D)‐type Ca2+‐channels showed both localized and uniform staining. In contrast, in GVBD‐arrested oocytes, none of the three types of Ca2+‐channels were identified in 72–86% of oocytes. The present study demonstrates that in most GVBD‐arrested oocytes that do not mature to MII, there is no Ca2+‐channel identified. Therefore, most of the GVBD‐arrested oocytes seem to have defects in Ca2+‐channel expression/translation. Also, distributional changes of Ca2+‐channels take place depending on the maturation progress in GV oocytes and MII stage oocytes (ovulated and 17 hr cultured MII stage oocytes). In addition, we found evidence that a functional voltage‐dependent Ca2+‐channel (L‐type) exists in mouse oocytes (ovulated and cultured MII staged oocytes by a confocal laser scanning microscope). Mol. Reprod. Dev. 69: 174–185, 2004. © 2004 Wiley‐Liss, Inc.