bluuebunny/crossref_metadata_2025 huggingface dataset:
Sonographic guidance for electron boost planning after breast‐conserving surgery
Authors: Warszawski Antje , Baumann Rolf , Karstens Johann H.
Published: July 2004

Purpose

This 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 Methods

Seventy‐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.

Results

The 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.

Conclusion

Sonography 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

Purpose

The 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.

Methods

We 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.

Results

Sonography 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.

Conclusions

Sonography 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

We 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

A 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

The 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

Changes 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

Here 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

The 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.
Effects of bone morphogenetic protein‐7 (BMP‐7) on primordial follicular growth in the mouse ovary
Authors: Lee Woo‐Sik , Yoon Se‐Jin , Yoon Tae‐Ki , Cha Kwang‐Yul , Lee Sook‐Hwan , Shimasaki Shunichi , Lee Sangho , Lee Kyung‐Ah
Published: July 2004

Previously, bone morphogenetic protein‐7 (BMP‐7) was suggested as a factor that may act to facilitate the transition of follicles from primordial stage to the pool of developed primary, preantral, and antral follicles (Lee et al. 2001: Biol Reprod 65:994–999.). Thus, aim of the present study was to evaluate effect(s) of BMP‐7 on the primordial‐primary follicle transition. Neonatal mouse ovaries were cultured in the presence or absence of 100 mIU/ml FSH with various doses of BMP‐7 (0, 10, and 100 ng/ml). After 4‐day culture period, number of follicles was counted and the expression of transcripts for FSH receptor (FSHR), kit ligand (KL), and c‐kit was measured by RT‐PCR. BMP‐7 alone at 100 ng/ml concentration stimulated follicle development with concurrent increase of mRNA for FSHR. BMP‐7 alone down‐regulated KL expression however, the ratio between KL1 and KL2 was increased. There was no change in the c‐kit mRNA expression. Results of the present study suggest that the BMP‐7 is one of the factors involved in primordial‐primary follicle transition in the mouse ovary and it may play a role in expression of FSHR for further follicular development. Mol. Reprod. Dev. 69: 159–163, 2004. © 2004 Wiley‐Liss, Inc.
Expression of gp20, a human sperm antigen of epididymal origin, is reduced in spermatozoa from subfertile men
Authors: Giuliani V. , Pandolfi C. , Santucci R. , Pelliccione F. , Macerola B. , Focarelli R. , Rosati F. , Della Giovampaola C. , Francavilla F. , Francavilla S.
Published: July 2004

gp20, a sialylglycoprotein of human sperm homologous to CD52, is present everywhere on the surface of the freshly ejaculated sperm but is prevalently localized in the equatorial region of the head of capacitated sperm. In the present study, we confirmed this feature on large scale and correlated equatorial exposure of the antigen to the presence of serum albumin (SA) in the capacitation medium. Furthermore, we analyzed the relationship between the presence of the antigen and its equatorial exposure after capacitation and fertility, by comparing immunostaining for gp20 in the motile fraction of spermatozoa from fertile and subfertile men. A significantly higher percentage of nonimmunostained spermatozoa before capacitation (38.5% ± 23 vs. 12% ± 7, P < 0.0001) and a lower increase in the percentage of sperm with equatorial localization after capacitation (19.3% ± 25 vs. 34.6% ± 22, P = 0.039) were observed in subfertile men (n = 60) compared to fertile men (n = 15). In the whole study group, a positive correlation was also found between the percentage of spermatozoa exhibiting equatorial localization in capacitated samples and normal head forms (R = 0.50; P < 0.0001). Mol. Reprod. Dev. 69: 235–240, 2004. © 2004 Wiley‐Liss, Inc.
Second‐order accurate constraint formulation for subdivision finite element simulation of thin shells
Authors: Green Seth , Turkiyyah George
Published: July 2004

We present a new method for enforcing boundary conditions within subdivision finite element simulations of thin shells. The proposed framework is demonstrated to be second‐order accurate with respect to increasing refinement in the displacement and energy norm for simply supported, clamped, free and symmetric boundary conditions. Second‐order accuracy on the boundary is consistent with the accuracy of subdivision‐based approaches for the interior of a body. Our proposed framework is applicable to both triangular and quadrilateral refinement schemes, and does not impose any topological requirements upon the underlying subdivision control mesh. Several examples from an obstacle course of benchmark problems are used to demonstrate the convergence of the scheme. Copyright © 2004 John Wiley & Sons, Ltd.
Healthcare resource utilization during 1‐year treatment with long‐acting, injectable risperidone
Authors: Leal A. , Rosillon D. , Mehnert A. , Jarema M. , Remington G.
Published: July 2004

Background

Schizophrenia is associated with disproportionately high costs, mainly due to hospitalization rates. This study assessed healthcare resource use in patients with schizophrenia and schizoaffective disorder during treatment with long‐acting risperidone.

Methods

Patients (n = 397 [inpatients, 24%; outpatients, 76%]) receiving stable doses of an antipsychotic for ≥4 weeks were eligible to enter this 1‐year, open‐label study. Following a 2‐week run‐in period (oral risperidone 1–6 mg/day), patients received intramuscular long‐acting risperidone (25 or 50 mg modal dose) every 2 weeks. Healthcare resource use in the previous 12 weeks was assessed at baseline and 12‐weekly intervals.

Results

Patients needing hospitalization decreased significantly and continuously from 38% during the 12 weeks before study entry to 12% during the last 12 weeks. Mean hospitalization length during the study was 30.5 days (outpatients, 4.9 days; inpatients, 110 days). This included 28 patients (7%) who remained in hospital throughout the study. During treatment, 71% of those hospitalized at baseline were discharged. Partial hospitalization decreased significantly from 7% of patients during the 12 weeks before treatment to 3% during the last 12 weeks. Outpatient consultations also decreased significantly from 70% of patients to 30% in the first 12 weeks of treatment and remained stable thereafter. Only 9% of patients required an emergency room visit; mostly for non‐psychiatric conditions.

Conclusion

Healthcare resource use is significantly reduced in patients with stable schizophrenia or schizoaffective disorder receiving long‐acting risperidone. It is highly likely that these reductions will decrease healthcare costs in patients receiving long‐acting risperidone. Copyright © 2004 John Wiley & Sons, Ltd.
Effectiveness of amoxicillin, azithromycin, cefprozil and clarithromycin in the treatment of acute otitis media in children: a population‐based study
Authors: Quach Caroline , Collet Jean‐Paul , LeLorier Jacques
Published: July 2004

Population‐based studies may give results different from randomized clinical trials assessing the efficacy of antibiotics.

Objective

To determine the effectiveness of amoxicillin, azithromycin, cefprozil and clarithromycin in the treatment of acute otitis media (AOM) in children.

Methods

Using Quebec Health Insurance databases (RAMQ), we selected a cohort of children aged ≤6 years, with a first episode of AOM between 1999 and 2002. The index AOM was defined as a medical service claim with a diagnosis of AOM and an antibiotic dispensation in the following 72 hours. Failures were defined as a new antibiotic dispensation, a hospitalization or outpatient visit for complications related to AOM in the 30 days after the index AOM. Data were analyzed using logistic regression.

Results

Overall, 12 693 failures occurred among 60 513 first episodes of AOM. Azithromycin was the only antibiotic that was associated with a decreased risk of failure overall, when compared to amoxicillin (OR 0.88, 95%CI: 0.82, 0.94). However in the first 3 days of treatment (n = 680), azithromycin was more associated with treatment failure (OR 1.6, 95%CI: 1.3, 2.0). Compared to amoxicillin, post‐therapy failures (n = 9387) were more likely to occur with cefprozil (OR 1.2, 95%CI: 1.2, 1.3) but were less with azithromycin (OR 0.8 95%CI: 0.8, 0.9).

Conclusions

Azithromycin had the lowest risk of failure 30 days after the onset of treatment but an increased risk of failure during the first few days of treatment. Amoxicillin remains an effective first‐line drug for treating first AOM episodes. Copyright © 2004 John Wiley & Sons, Ltd.
Molecular distribution analysis of melt‐crystallized ethylene copolymers
Authors: Chen Fei , Shanks Robert A , Amarasinghe Gandara
Published: July 2004

A simple technique employing differential scanning calorimetry (DSC) to investigate the molecular structure of ethylene copolymers is presented in this paper. Three commercial Ziegler–Natta catalysed linear low density polyethylenes (LLDPE) and a commercial single‐site catalysed very low density polyethylene (VLDPE) were subjected to continuous cooling at a slow rate of 0.08 °C min−1. Like other thermal fractionation techniques, the slow continuous cooling (SCC) technique segregates polymers according to their branching density, allowing the short chain branching (SCB), lamellar thickness (L) and methylene sequence length (MSL) distribution to be determined using the DSC melting curves. It was found that the single‐site catalysed VLDPE exhibits narrow SCB, L and MSL distributions, with shorter methylene sequences. In contrast, the Ziegler–Natta catalysed LLDPEs have much broader bimodal SCB, L and MSL distributions, with less SCB, and are composed of both short and long methylene sequences. LLDPEs have thicker lamellae compared with VLDPE (12.9, 12.5, 9.8 nm versus 6.7 nm) and the lamellar thickness values are consistent with the results measured by transmission electron microscopy (TEM). The slow continuous cooling and stepwise cooling techniques are complementary: the former provides a continuous distribution profile and the latter a well‐defined histogram for the lamellar thickness. The results obtained are qualitatively comparable to those gained by temperature rising elution fractionation (TREF), because the cooling rate used here is of the order of the rates used in TREF analysis. Copyright © 2004 Society of Chemical Industry
Effects of solvents on electrospun polymeric fibers: preliminary study on polystyrene
Authors: Wannatong Ladawan , Sirivat Anuvat , Supaphol Pitt
Published: July 2004

Six solvents [acetic acid, acetonitrile, m‐cresol, toluene, tetrahydrofuran (THF) and dimethylformamide (DMF)] with different properties (eg density, boiling point, solubility parameter, dipole moment and dielectric constant) were used to prepare electrospun polystyrene (PS) fibers. Fiber diameters were found to decrease with increasing density and boiling point of the solvents. A large difference between the solubility parameters of PS and the solvent was responsible for the bead‐on‐string morphology observed. Productivity of the fibers (the numbers of fiber webs per unit area per unit time) increased with increasing dielectric constant and dipole moment of the solvents. Among the solvents studied, DMF was the best solvent that provided PS fibers with highest productivity and optimal morphological characteristics. The beadless, well‐aligned PS fibers with a diameter of ca 0.7 µm were produced from the solution of 10 % (w/v) of PS in DMF at an applied electrostatic field of 15 kV/10 cm, a nitrogen flow rate of 101 ml min−1 and a rotational speed of the collector of 1500 rev min−1. Copyright © 2004 Society of Chemical Industry
Predictive reconstruction of the mitochondrial iron‐sulfur cluster assembly metabolism. II. Role of glutaredoxin Grx5
Authors: Alves Rui , Herrero Enrique , Sorribas Albert
Published: July 2004

Grx5 is a Saccharomyces cerevisiae glutaredoxin involved in iron‐sulfur cluster (FeSC) biogenesis. Previous work suggests that Grx5 is involved in regulating protein cysteine glutathionylation, prompting several questions about the systemic role of Grx5. First, is the regulation of mixed protein‐glutathione disulfide bridges in FeSC biosynthetic proteins by Grx5 sufficient to account for the observed phenotypes of the Δgrx5 mutants? If so, does Grx5 regulate the oxidation state of mixed protein‐glutathione disulfide bridges in FeSC biogenesis in general? Alternatively, can the Δgrx5 mutant phenotypes be explained if Grx5 acts on just one or a few of the FeSC biogenesis proteins?

In the first part of this article, we address these questions by building and analyzing a mathematical model of FeSC biosynthesis. We show that, independent of the tested parameter values, the dynamic behavior observed in cells depleted of Grx5 can only be qualitatively reproduced if Grx5 acts by regulating the initial assembly of FeSC in scaffold proteins. This can be achieved by acting on the cysteine desulfurase (Nfs1) activity and/or on scaffold functionality.

In the second part of this article, we use structural bioinformatics methods to evaluate the possibility of interaction between Grx5 and proteins involved in FeSC biogenesis. Based on such methods, our results indicate that the proteins with which Grx5 is more likely to interact are consistent with the kinetic modeling results.

Thus, our theoretical studies, combined with known Grx5 biochemistry, suggest that Grx5 acts on FeSC biosynthesis by regulating the redox state of important cysteine residues in Nfs1 and/or in the scaffold proteins where FeSC initially assemble. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Prediction of protein accessible surface areas by support vector regression
Authors: Yuan Zheng , Huang Bixing
Published: July 2004

A novel support vector regression (SVR) approach is proposed to predict protein accessible surface areas (ASAs) from their primary structures. In this work, we predict the real values of ASA in squared angstroms for residues instead of relative solvent accessibility. Based on protein residues, the mean and median absolute errors are 26.0 Å2 and 18.87 Å2, respectively. The correlation coefficient between the predicted and observed ASAs is 0.66. Cysteine is the best predicted amino acid (mean absolute error is 13.8 Å2 and median absolute error is 8.37 Å2), while arginine is the least predicted amino acid (mean absolute error is 42.7 Å2 and median absolute error is 36.31 Å2). Our work suggests that the SVR approach can be directly applied to the ASA prediction where data preclassification has been used. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Characterization of the conformational space of a triple‐stranded β‐sheet forming peptide with molecular dynamics simulations
Authors: Soto Patricia , Colombo Giorgio
Published: July 2004

Molecular dynamics (MD) simulations have been performed on a series of mutants of the 20 amino acid peptide Betanova in order to critically assess the ability of MD simulations to reproduce the folding and stability of small β‐sheet–forming peptides on currently accessible timescales. Simulations were performed in both water and in 40% methanol solution, using an explicit solvent model. The simulations suggest that all mutants adopt a wide range of conformations in solution, that the structures are highly flexible, and that stabilization of compact structures is due to a delicate balance of hydrophobic and polar side‐chain interactions. Simulations longer than 100 ns, although not sufficient for a complete thermodynamic and kinetic description of the system, sample an ensemble of compact conformations characterized by the loss of ordered β‐sheet secondary structure. This suggests that no significant free energy barrier separates the different conformations available. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Multi‐method global analysis of thermodynamics and kinetics in reconstitution of monellin
Authors: Xue Wei‐Feng , Carey Jannette , Linse Sara
Published: July 2004

Accurate and precise determinations of thermodynamic parameters of binding are important steps toward understanding many biological mechanisms. Here, a multi‐method approach to binding analysis is applied and a detailed error analysis is introduced. Using this approach, the binding thermodynamics and kinetics of the reconstitution of the protein monellin have been quantitatively determined in detail by simultaneous analysis of data collected with fluorescence spectroscopy, surface plasmon resonance and isothermal titration calorimetry at 25°C, pH 7.0 and 150 mM NaCl. Monellin is an intensely sweet protein composed of two peptide chains that form a single globular domain. The kinetics of the reconstitution reaction are slow, with an association rate constant, kon of 8.8 × 103 M−1 s−1 and a dissociation rate constant, koff of 3.1 × 10−4 s−1. The equilibrium constant KA is 2.8 × 107 M−1 corresponding to a standard free energy of association, ΔG°, of −42.5 kJ/mol. The enthalpic component, ΔH°, is −18.7 kJ/mol and the entropic contribution, ΔS°, is 79.8 J mol−1 K−1 (−TΔS° = −23.8 kJ/mol). The association of monellin is therefore a bimolecular intra‐protein association whose energetics are slightly dominated by entropic factors. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Probabilistic models for life‐cycle performance of deteriorating structures: review and future directions
Authors: Frangopol Dan M , Kallen Maarten‐Jan , Noortwijk Jan M van
Published: July 2004

In comparison with the well‐researched field of analysis and design of structural systems, the life‐cycle performance prediction of these systems under no maintenance as well as under various maintenance scenarios is far more complex, and is a rapidly emergent field in structural engineering. As structures become older and maintenance costs become higher, different agencies and administrations in charge of civil infrastructure systems are facing challenges related to the implementation of structure maintenance and management systems based on life‐cycle cost considerations. This article reviews the research to date related to probabilistic models for maintaining and optimizing the life‐cycle performance of deteriorating structures and formulates future directions in this field.
Studies of observed trends in values of Bethe–Bloch parameters extracted from stopping power measurements
Authors: Porter L. E.
Published: July 2004

In the course of previous investigations, trends in values of the Bethe–Bloch parameters, mean excitation energy (I) and Barkas‐effect parameter (b), have been observed. Generally I values decrease with increasing projectile atomic number (z) whereas b values increase. However, the opposite trends have been previously observed for ZnSe and GaAs targets traversed by 1H and 4He projectiles. In the present study, that opposite trend was also followed when 7Li projectiles were included. When selected measurements for 4He, 12C, 14N, and 16O projectiles impinging on Si targets were analyzed, extracted I and b values followed essentially the original trends in z dependence. Stopping power measurements for 12 elemental targets with atomic numbers (Z) lying between 12 and 48 traversed by 29Si projectiles have been analyzed for determination of values of a single effective charge parameter, as part of a continuing study of systematics in such values in terms of both z and Z. Two other sets of measurements featuring 7Li projectiles and eight elemental targets with Z values between 5 and 48 have been similarly analyzed. In some of the effective charge studies the data proved amenable to extraction of three parameters, so that results could be included in the ongoing study of z dependences of extracted values of I and b. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Generation and characterization of ionic and neutral methylene isothiocyanate by a combined tandem mass spectrometry and computational study
Authors: Reddy P. Nagi , Srikanth R. , Bhanuprakash K. , Srinivas R.
Published: July 2004

The heterocumulene, methyleneisothiocyanate ion, CH2NCS+ (1a+), is generated by the dissociative electron ionization of 2‐mercaptoimidazole. This conclusion follows from tandem mass spectrometry experiments and theoretical calculations at the B3LYP/6‐311G** and G2/G2(MP2) levels. The calculations predict that 1a+ is separated by high energy barriers from its isomers CHNCHS (1b+), CHNCSH (1d+), CNCHSH (1e+) and CHNHCS (1f+). The low energy metastable ions 1a+ dissociate by loss of HCN via the pathway 1a+ → 1b+ → HCS+ + HCN. Neutralization‐reionization experiments confirm the theoretical prediction that the hitherto unknown heterocumulene CH2NCS. is a stable species in the rarefied gas phase. Copyright © 2004 John Wiley & Sons, Ltd.
Determination of ochratoxin A in meat products by high‐performance liquid chromatography coupled to electrospray ionisation sequential mass spectrometry
Authors: Losito I. , Monaci L. , Palmisano F. , Tantillo G.
Published: July 2004

A method based on liquid chromatography with electrospray ionisation ion trap mass spectrometry, for the determination of ochratoxin A (OTA) in meat products using ochratoxin B (OTB) as an internal standard, is described. Fragmentation patterns of OTA and OTB were studied by sequential mass spectrometry. Trace determination was then accomplished by consecutive reaction monitoring (CRM) of a fragment obtained by MS3 experiments. This led to a better signal‐to‐noise ratio and to a higher specificity of the technique. The response to OTA was linear over at least one concentration decade with a limit of detection of 0.6 ng/g. The method was applied to pig tissue samples naturally contaminated by OTA. Copyright © 2004 John Wiley & Sons, Ltd.
Abgehängte Fassaden im Zentrum Paul Klee
Authors: Lang Robert , Schmid Volker
Published: July 2004

Die sichtbare Gebäudehülle des “Zentrum Paul Klee” in Bern besteht nur aus zwei Elementen – der wellenförmigen Dachstruktur und der markanten, zweistöckigen Frontfassade. Der vorliegenden Aufsatz erläutert den Entwurf und die Konstruktionsprinzipien der bis zu 19,5 m hohen, von den Frontbögen abgehängten Glasfassaden. Die Wahl des Tragsystems wird insbesondere von den großen Verformungen des Bogendaches bestimmt, die möglichst zwängungsfrei von den Fassaden aufgenommen werden müssen. Ein quer zur Fassadenebene angeordneter “Balancier” wird eingeführt, um Spannkraftverluste in den oberen vorgespannten Kabeln zu vermeiden.
Form follows performance: Entwicklung des modularen, weitgespannten Tragwerks für ein neues Montagewerk
Authors: Reichardt Jürgen , Eckert Andreas , Baum Thomas
Published: July 2004

Zunehmender globaler Wettbewerb erfordert gegenwärtig für alle Projektbeteiligten besondere Anstrengungen im Hinblick auf Qualität, Termintreue und Kostenbewußtsein. Für Konzeption, Projektsteuerung, Realisierung und das Betreiben komplexer Fabrikbauten bedeutet das in der Automobilindustrie geläufige Prinzip der ‘zero tolerance’ insbesondere die Vermeidung von Schnittstellen bisweilen separierter Fachplanungen. Der Aufbau eines integrierten, durchgängigen 3D‐Datenmodells nutzt die Potentiale gegenwärtiger CAD/CAM‐Datenbanktechniken zugunsten einer übergreifenden Projektoptimierung und zyklischen 3D‐Qualitätssicherung. Die Methodik der synergetischen Fabrikplanung wird am Fallbeispiel der Entwicklung eines modularen, weitgespannten Tragwerks erläutert und zur Diskussion gestellt.
Numerische Untersuchungen zur Ermüdungsbeanspruchung vorgespannter Ringflanschstöße mit Imperfektionen
Authors: Jakubowski Alexander , Schmidt Herbert
Published: July 2004

Für die Bemessung vorgespannter geschraubter Ringflanschstöße in turmartigen Stahlbauten (z. B. Schornsteine oder Rohrtürme von Windenergieanlagen) ist der Nachweis gegen Ermüdung der Schrauben sehr wichtig. Klaffungen zwischen den Kontaktflächen vor dem Vorspannen der Schrauben (sogenannte Flanschimperfektionen) können einen negativen Einfluß auf die ermüdungsrelevanten Schraubenspannungen haben. Es wurde ein FE‐Modell für imperfekte Ringflansche aufgebaut und mit Hilfe der Ergebnisse großmaßstäblicher Rohrbiegeversuche an Ringflanschstößen validiert. Über diese Versuche war ebenfalls in dieser Zeitschrift berichtet worden. Mit dem validierten FE‐Modell wurde eine Parameterstudie an imperfekt simulierten L‐Ringflanschverbindungen mit baupraktischen Abmessungen aus dem WEA‐Bau durchgeführt. Die Ergebnisse ermöglichen eine Differenzierung der verschiedenen Klaffungsformen hinsichtlich ihres negativen Einflusses auf die Schraubenermüdung. Dieser Einfluß darf beim Ermüdungssicherheitsnachweis der Schrauben keinesfalls vernachlässigt werden.
Selective dopamine D3 receptor antagonist SB‐277011‐A potentiates phMRI response to acute amphetamine challenge in the rat brain
Authors: Schwarz Adam , Gozzi Alessandro , Reese Torsten , Bertani Simone , Crestan Valerio , Hagan Jim , Heidbreder Christian , Bifone Angelo
Published: July 2004

Dopamine (DA) receptors are a major target for drugs employed in the treatment of neuropsychiatric disorders such as schizophrenia and drug dependence. The D3 subtype of the D2 DA receptor family presents a particularly focal distribution in limbic brain areas known to be associated with cognitive and emotional functions. This study examined the modulation of brain activation induced by acute administration of amphetamine in the rat by the highly selective DA D3 receptor antagonist SB‐277011‐A using relative cerebral blood volume (rCBV) pharmacological MRI (phMRI). The acute administration of D‐amphetamine (1 mg/kg i.v.) produced a widespread rCBV response that was strongest in cortical regions. SB‐277011‐A (20 mg/kg i.p.) itself did not produce significant changes in rCBV, but potentiated the phMRI response to 1 mg/kg i.v. D‐amphetamine in a regionally specific manner, involving a number of structures outside the focal distribution of the D3 receptor. Potentiated regions included the accumbens, dorsal caudate putamen, islands of Calleja, thalamus, cingulate cortex, ventral tegmental area, dorsal Raphe nucleus, and ventral subiculum. The increased response following D3 receptor antagonism is consistent with this receptor mediating an inhibitory action on brain activity following a dopaminergic stimulus. Synapse 54:1–10, 2004. © 2004 Wiley‐Liss, Inc.
Cocaine alters GABAB‐mediated G‐protein activation in the ventral tegmental area of female rats: Modulation by estrogen
Authors: Febo Marcelo , Segarra Annabell C.
Published: July 2004

In female rats, estrogen has been reported to enhance cocaine sensitization. Here we investigated the effect of estrogen and cocaine treatments on GABAB‐stimulated [35S]GTPγS binding. Ovariectomized rats without (OVX) and with estrogen treatment (OVX‐EB) were pretreated with saline or cocaine (15 mg/kg, i.p.) for 5 days and after 1 week of withdrawal challenged with cocaine. One hour after the final injection, animals were sacrificed, brains immediately frozen, and stored at −70°C for subsequent cryosectioning. In vitro functional autoradiography was performed using baclofen (300 μM), a GABAB receptor agonist, to stimulate [35S]GTPγS binding in tissue sections at the level of the ventral tegmental area (VTA). OVX‐EB rats showed lower levels of [35S]GTPγS binding in the VTA (−15%) and entorhinal cortex (EC) (−60%). The effect of cocaine on GABAB‐mediated G‐protein activation varied with the presence of estrogen. Repeated cocaine administration reduced [35S]GTPγS binding in the VTA and EC of OVX rats and increased it in OVX‐EB. Thus, our data suggest that estrogen reduces GABAB‐mediated G‐protein activation in female rats. The results also show that estrogen strongly influences cocaine‐induced alterations in GABAB function in the VTA and EC of female rats. Synapse 54:30–36, 2004. © 2004 Wiley‐Liss, Inc.
FI Catalysts: new olefin polymerization catalysts for the creation of value‐added polymers
Authors: Mitani Makoto , Saito Junji , Ishii Sei‐ichi , Nakayama Yasushi , Makio Haruyuki , Matsukawa Naoto , Matsui Shigekazu , Mohri Jun‐ichi , Furuyama Rieko , Terao Hiroshi , Bando Hideki , Tanaka Hidetsugu , Fujita Terunori
Published: July 2004

This contribution reports the discovery and application of phenoxy–imine‐based catalysts for olefin polymerization. Ligand‐oriented catalyst design research has led to the discovery of remarkably active ethylene polymerization catalysts (FI Catalysts), which are based on electronically flexible phenoxy–imine chelate ligands combined with early transition metals. Upon activation with appropriate cocatalysts, FI Catalysts can exhibit unique polymerization catalysis (e.g., precise control of product molecular weights, highly isospecific and syndiospecific propylene polymerization, regio‐irregular polymerization of higher α‐olefins, highly controlled living polymerization of both ethylene and propylene at elevated temperatures, and precise control over polymer morphology) and thus provide extraordinary opportunities for the syntheses of value‐added polymers with distinctive architectural characteristics. Many of the polymers that are available via the use of FI Catalysts were previously inaccessible through other means of polymerization. For example, FI Catalysts can form vinyl‐terminated low molecular weight polyethylenes, ultra‐high molecular weight amorphous ethylene–propylene copolymers and atactic polypropylenes, highly isotactic and syndiotactic polypropylenes with exceptionally high peak melting temperatures, well‐defined and controlled multimodal polyethylenes, and high molecular weight regio‐irregular poly(higher α‐olefin)s. In addition, FI Catalysts combined with MgCl2‐based compounds can produce polymers that exhibit desirable morphological features (e.g., very high bulk density polyethylenes and highly controlled particle‐size polyethylenes) that are difficult to obtain with conventionally supported catalysts. In addition, FI Catalysts are capable of creating a large variety of living‐polymerization‐based polymers, including terminally functionalized polymers and block copolymers from ethylene, propylene, and higher α‐olefins. Furthermore, some of the FI Catalysts can furnish living‐polymerization‐based polymers catalytically by combination with appropriate chain transfer agents. Therefore, the development of FI Catalysts has enabled some crucial advances in the fields of polymerization catalysis and polymer syntheses. © 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 137–158; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20010
Metal‐catalyzed living radical polymerization: discovery and developments
Authors: Kamigaito Masami , Ando Tsuyoshi , Sawamoto Mitsuo
Published: July 2004

Control of radical polymerization has been one of the most challenging frontiers in polymerization chemistry. This review presents the discovery of metal‐catalyzed living radical polymerization and recent developments in the evolution of catalysts in terms of versatility and activity, scope of monomers, controlled polymerization in water, catalyst removal, and precision synthesis of well‐controlled polymers such as random, block, end‐functionalized, and star polymers. © 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 159–175; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20011