bluuebunny/crossref_metadata_2025 huggingface dataset:
New Attempt at the Stereoselective Polymerization of Lactide by Using Crystallization during Polymerization
Authors: Ando Akihiro , Kimura Kunio , Onda Yuko , Yamashita Yuhiko
Published: January 2005

Summary: The stereoselective polymerization of partial rac‐lactide was attempted by using crystallization during polymerization. Polymerizations were carried out with trifluoromethanesulfonic acid in a mixed solvent of toluene and octane. The molar content of L‐lactate in the feed was 95%. Polymerization proceeded with the elimination of D‐lactate by means of crystallization. Poly(L‐lactic acid) (PLLA) crystals were first precipitated and then plate‐like poly(lactic acid) (PLA) crystals were finally obtained, of which the composition of L‐lactate was 97.6% and the $\overline M _{\rm n}$ was 1.68 × 104.

The polymerization time dependence of the microstructure of poly(lactic acid), i.e., the percentage of mm triads (mm%), prepared from partial rac‐lactide in toluene‐70.

image

The polymerization time dependence of the microstructure of poly(lactic acid), i.e., the percentage of mm triads (mm%), prepared from partial rac‐lactide in toluene‐70.
Synthesis of Glucose‐Containing Polyaniline by the Oxidative Polymerization of N‐Glucosylaniline
Authors: Kadokawa Jun‐ichi , Shinmen Yuusuke , Shoda Shin‐ichiro
Published: January 2005

Summary: The oxidative polymerization of N‐glucosylaniline was carried out using ammonium persulfate as the oxidant in phosphate buffer. The structure of the isolated polymer was determined by 1H NMR, 13C NMR, and UV‐vis spectroscopy to be the polyaniline having glucose residues attached to the general polyaniline unit. Participation of the ortho‐position of the aromatic ring in the polymerization was also confirmed by the analyses.

The oxidative polymerization of N‐glucosylaniline.

image

The oxidative polymerization of N‐glucosylaniline.
Crystallization of Polystyrene‐block‐[Syndiotactic Poly(propylene)] Block Copolymers from Confinement to Breakout
Authors: Ho Rong‐Ming , Chung Tsai‐Ming , Tsai Jing‐Cherng , Kuo Jing‐Chang , Hsiao Benjamin S. , Sics Igors
Published: January 2005

Summary: Various crystalline textures have been identified in a crystallizable block copolymer system, polystyrene‐block‐[syndiotactic poly(propylene)] (PS‐sPP), having a glass‐transition temperature of PS (Tg,PS) located in the midst of the sPP crystallization window. A confined morphology for the crystallization of sPP was observed while the crystallization temperature of sPP (Tc,sPP) was less than Tg,PS. A further increase in Tc,sPP could lead to a breakout in nanostructure. This study revealed the Tg effect on crystallization‐induced morphological changes of block copolymers from confinement to breakout.

TEM images and one‐dimensional SAXS profiles of PS‐sPP isothermally crystallized at TODT > Tg,PS > Tc,sPP (top) and TODT > Tc,sPP > Tg,PS (bottom).

image

TEM images and one‐dimensional SAXS profiles of PS‐sPP isothermally crystallized at TODT > Tg,PS > Tc,sPP (top) and TODT > Tc,sPP > Tg,PS (bottom).
Oxidative stress and uremia
Authors: Floccari Fulvio , Aloisi Carmela , Crascì Eleonora , Sofi Tito , Campo Susanna , Tripodo Donatella , Criseo Manila , Frisina Nicola , Buemi Michele
Published: January 2005

Oxidative stress is a pathogenic element of great importance in uremic patients, with a great impact on their survival. The cause of oxidative stress in patients on hemodialysis is traditionally attributed to the recurrent activation of polymorphonucleate neutrophils and monocytes. The effects of oxidative stress are evident on all biochemical components of biological tissues: lipids, proteins, carbohydrates, and nucleic acids. This study briefly reviews the effects of different dialytic techniques and of kidney transplant on several parameters of oxidative stress. Many different modalities of pharmaceutical intervention are then analyzed, and the clinical evidences reported. © 2005 Wiley Periodicals, Inc.
X‐linked Charcot–Marie–Tooth disease: Phenotypic expression of a novel mutation Ile127Ser in the GJB1 (connexin 32) gene
Authors: Vondracek Petr , Seeman Pavel , Hermanova Marketa , Fajkusova Lenka
Published: January 2005

We report a family with X‐linked dominant Charcot–Marie–Tooth disease (CMTX1). Three affected family members are described, who underwent detailed clinical, electrophysiological, molecular genetic, and histopathological studies. A novel isoleucine at position 127 with serine (Ile127Ser) mutation in the gap junction protein beta 1 (GJB1) gene was detected. The electrophysiological findings were consistent with a primary demyelinating neuropathy with secondary axonal loss and support this model of disease progression. All patients having the CMT phenotype and intermediate conduction velocities who are negative for CMT1A duplication/hereditary neuropathy with liability to pressure palsies (HNPP) deletion, and whose family shows a dominant trait without male‐to‐male transmission, should be screened for CMTX1. Muscle Nerve, 2004
Diversity in expression and prognostic significance of G1/S cyclins in human primary lung carcinomas
Authors: Dobashi Yoh , Jiang Shi‐Xu , Shoji Mitsuhiko , Morinaga Shojiroh , Kameya Toru
Published: January 2005

Expression of cyclin A, cyclin E and cdk2 was examined immunohistochemically in 144 cases of primary non‐small cell lung carcinoma to evaluate their prognostic value. Cyclin A was co‐expressed with cdk2 in the proliferating cells, ie those showing positive Ki‐67 staining. The labelling index (LI) of cyclin A revealed a positive correlation with the S‐phase fraction and an inverse correlation with histological differentiation. Furthermore, high cyclin A LIs indicated a poor prognosis in all histological types. Cyclin E exhibited a characteristic staining pattern: in squamous cell carcinoma (SCC), differentiated cells without Ki‐67 staining revealed cyclin E positivity with expression of cdk2. Conversely, in adenocarcinoma (AC), proliferating cells revealed cyclin E positivity. Cases of large cell carcinoma showed heterogeneous cyclin E staining patterns, unlike those of SCC or AC. Statistical analyses also revealed a marked contrast between SCC and AC. In AC, the LI of cyclin E was inversely correlated with histological differentiation and a high LI predicted a worse prognosis. In contrast, in SCC, the LI of cyclin E correlated positively with histological differentiation and better prognosis. However, the expression levels of cyclin E mRNA evaluated by quantitative RT‐PCR were higher in poorly differentiated SCC and AC, suggesting that protein turnover plays a large role in determining cyclin E protein levels. Although the expression of cyclins was demonstrated to be diversely regulated depending on the histological type, the combined immunohistochemical analyses performed in this study on these proteins could be useful tools for evaluating patient prognosis in lung carcinomas. Copyright © 2002 John Wiley & Sons, Ltd.
Liver pathology and hepatocarcinogenesis in a long‐term mouse model of erythropoietic protoporphyria
Authors: Libbrecht Louis , Meerman Leo , Kuipers Folkert , Roskams Tania , Desmet Valeer , Jansen Peter
Published: January 2005

Erythropoietic protoporphyria (EPP) is an inherited disease of haem synthesis caused by a mutation in one of the alleles of the enzyme ferrochelatase. This mutation leads to partial deficiency of the enzyme, resulting in increased concentrations of protoporphyrin (PP) in blood, liver, and faeces. Five to ten per cent of patients with EPP develop severe liver disease characterized by the presence of PP deposits. This study used histochemistry and immunohistochemistry to investigate the histopathological features present in the livers of 44 mice with a heterozygous or homozygous point mutation in the ferrochelatase gene (fch/+ and fch/fch mice, respectively). Some fch/+ mouse livers showed mixed steatosis and large cell dysplasia. The livers of fch/fch mice showed periportal or septal fibrosis accompanied by an atypical ductular reaction. These findings suggest that the obstruction and damage of a proportion of large and small bile ducts by PP deposits cause an accumulation of PP in the parenchyma, which leads to damage and loss of hepatocytes due to the toxic effects of PP. The classical stages of hepatocarcinogenesis were observed and hepatic progenitor cells appear to be involved in this process. PP acts as the promoting agent and is probably also the initiating agent. Copyright © 2002 John Wiley & Sons, Ltd.
Papillary carcinoma of the thyroid: evidence for a role for hepatocyte growth factor (HGF) in promoting tumour angiogenesis
Authors: Scarpino Stefania , Cancellario d'Alena Francesca , Di Napoli Arianna , Ballarini Francesca , Prat Maria , Ruco Luigi P
Published: January 2005

The pattern of vascularization of papillary carcinoma was investigated in tumour sections from 31 cases and in primary cultures from 12 cases. Tumour sections were immunostained for von Willebrand Factor (vWF) to visualize blood vessels; for endothelial‐specific nitric‐oxide‐synthase (EC‐NOS), as a marker of endothelial cell activation; and for Ki‐67 to evaluate endothelial cell proliferation. It was found that endothelial cells lining venous vessels located in peritumoural fibrous tissue were intensely EC‐NOS‐positive and occasionally Ki‐67‐positive. Capillary vessels of tumour papillae were not stained for Ki‐67 and were weakly EC‐NOS‐positive. Primary cultures of papillary carcinoma cells were used as a potential source of factors active on endothelial cells. It was found that thyroid tumour cells contain RNAs for angiopoietin, vascular endothelial growth factor (VEGF), and VEGF‐C; moreover, they release large amounts of VEGF into culture supernatants and exert chemotactic activity in vitro for the endothelial cell line SIEC. The ability of papillary carcinoma cells to release angiogenic factors could be stimulated in vitro. Hepatocyte growth factor (HGF; 25 ng/ml) induced a 1.2‐ to 5‐fold increase in the amount of VEGF released by tumour cells and a 1.2‐ to 4.2‐fold increase in the amount of chemotactic activity present in culture supernatants. Met protein, the high affinity HGF‐receptor, is overexpressed in a large proportion of cases of papillary carcinoma. These findings are consistent with the possibility that HGF–Met protein interaction is one of the molecular mechanisms promoting the vascularization of papillary carcinoma of the thyroid. Copyright © 2003 John Wiley & Sons, Ltd.
High‐throughput tissue microarray analysis of G1‐cyclin alterations in classical Hodgkin's lymphoma indicates overexpression of cyclin E1
Authors: Tzankov Alexandar , Zimpfer Annette , Lugli Alessandro , Krugmann Jens , Went Philip , Schraml Peter , Maurer Robert , Ascani Stefano , Pileri Stefano , Geley Stephan , Dirnhofer Stephan
Published: January 2005

Deregulation of G1‐cyclins (CCN) plays a key role in the pathogenesis of many human malignancies, including non‐Hodgkin's lymphomas (NHLs). In contrast to NHL, little is known about phenotypic and genotypic changes in the regulation of the cell cycle in classical Hodgkin's lymphoma (cHL). To facilitate analysis of aberrant gene expression in cHL, a lymphoma tissue microarray (TMA) containing 752 cores of 330 different cHL samples was constructed. Direct comparison of Epstein–Barr virus (EBV) latent membrane protein 1 (LMP‐1) expression in Hodgkin's and Reed–Sternberg (HRS) cells on conventional full sections with the corresponding duplicate/triplicate tumour cores on the TMA showed a concordance of 100%, indicating that cHL‐TMA is a reliable and representative method for evaluating gene expression profiles in situ. Using TMA technology, protein expression and gene amplification of different G1‐CCNs in cHL were analysed. Among the G1‐CCNs analysed, cyclin E (CCNE) was expressed in 212/253 cases (84%). In most of the individual tumours, over 75% of the HRS cells stained positive for CCNE, suggesting that CCNE is overexpressed in cHL. This overexpression was not due to CCNE gene amplification, as judged by fluorescence in situ hybridization, and did not correlate with EBV infection, as assessed by the expression of LMP‐1. Thus, the overexpression of CCNE could be caused by profound changes in HRS cell‐cycle regulation that could contribute to the malignant phenotype. Copyright © 2003 John Wiley & Sons, Ltd.
NEDD8 protein is involved in ubiquitinated inclusion bodies
Authors: Dil Kuazi Afroz , Kito Katsumi , Abe Yasuhito , Shin Ryong‐Woon , Kamitani Tetsu , Ueda Norifumi
Published: January 2005

Proteolysis by the ubiquitin–proteasome system is considered to play a pathological role in several degenerative diseases that involve ubiquitinated inclusion bodies. In recent years, several ubiquitin‐like proteins have been isolated, but it is uncertain whether their roles are associated with protein degradation through the ubiquitin–proteasome system. NEDD8 (neural precursor cell‐expressed and developmentally down‐regulated gene), which consists of 81 amino acid residues, possesses the highest sequence similarity to ubiquitin. Recent studies have indicated that NEDD8 is covalently ligated to cullin family proteins, which are components of certain ubiquitin E3 ligases, by a pathway analogous to that of ubiquitin. Thus, by focusing on the structural and functional association between NEDD8 and ubiquitin, it would be of interest to know whether the NEDD8 system is involved in pathological disorders of the ubiquitin–proteasome system. This study has examined the immunohistochemical distribution of NEDD8 protein by using a highly purified antibody in normal tissues and in tissues known to contain ubiquitinated inclusions. NEDD8 protein expression was widely observed in most types of tissues. Furthermore, accumulation of the NEDD8 protein was commonly observed in ubiquitinated inclusion bodies, including Lewy bodies in Parkinson's disease, Mallory bodies in alcoholic liver disease, and Rosenthal fibres in astrocytoma. Two of ten cases of neurofibrillary tangles and senile plaques from patients with Alzheimer's disease showed intense staining for NEDD8 as well as for ubiquitin. These findings suggest the possibility that the NEDD8 system is involved in the metabolism of these inclusion bodies via the ubiquitin–proteasome system. Copyright © 2003 John Wiley & Sons, Ltd.
Self‐efficacy and self‐concept as predictors of college students' academic performance
Authors: Choi Namok
Published: January 2005

Social cognitive theory suggests that self‐constructs are better predictors when the specificity levels of self‐constructs (as predictors) and the criterion variable closely correspond. In this study it was examined whether self‐constructs measured at an intermediate level of specificity better correspond with the criterion variable (course grades: an intermediate level of specificity) than general self‐constructs or specific self‐constructs. Self‐constructs in this study included self‐efficacy and self‐concept at varying degrees of specificity: general self‐efficacy, academic self‐efficacy, specific self‐efficacy, academic self‐concept, and specific self‐concept. College students (N = 230) in general education courses voluntarily completed the three self‐efficacy measures and the two self‐concept measures. Results of correlation and simultaneous multiple regression analyses indicated that the closer the level of specificity of self‐efficacy and self‐concept, the stronger the relationship between the two constructs. Both academic self‐concept and specific self‐concept were significant predictors of term grades. In addition, academic self‐concept was also a significant predictor, whereas neither general self‐efficacy nor academic self‐efficacy was significant. Measurement issues and implications of the findings are discussed. © 2005 Wiley Periodicals, Inc. Psychol Schs 42: 197–205, 2005.
Using behavioral and academic indicators in the classroom to screen for at‐risk status
Authors: Belsito Laura , Ryan Bruce A. , Brophy Kathleen
Published: January 2005

The present study validated a brief at‐risk screening instrument designed for easy use by teachers in the elementary school. School performance measures were collected for students in first to sixth grade one year following initial teacher ratings using the Screening For At‐Risk Status screening instrument. Findings indicated that the instrument is best seen as measuring a single at‐risk construct with items drawn from three domains: academic skills, social confidence, and social cooperation. Correlations between at‐risk scores and school performance measures taken one year later demonstrated predictive validity. The screening instrument correctly identified at‐risk students with 88% accuracy and not‐at‐risk students with 74% accuracy. There were 12% false negatives. Use of the instrument provides teachers with a quick, easy screening of students who may develop difficulties in the future. For schools, the screening can be used as the first step in a supportive response system to assist at‐risk students from developing serious school difficulties and possibly failure in the longer term. © 2005 Wiley Periodicals, Inc. Psychol Schs 42: 151–158, 2005.
Situational specificity makes the difference in assessment of youth behavior disorders
Authors: McDermott Paul A. , Steinberg Carrie M. , Angelo Lauren E.
Published: January 2005

In this article we examine the ability of contextual information to enhance assessment of behavior problems in schools. Capitalizing on the multisituational structure of the Adjustment Scales for Children and Adolescents, exploratory and confirmatory analyses with a representative national sample (N= 1,400, ages 5–17 years) revealed three unique and reliable behavioralsitutypes(problems in Peer Contexts, Academic Contexts, and Teacher Contexts). The situtypes were found internally consistent and structurally generalizable across age, sex, and ethnicity. Multiple logistic and discriminant analyses confirmed the ability of the situtypes to identify accurately those youth independently diagnosed as emotionally disturbed, as well as distinguish those diagnosed as learning disabled. Information gleaned from the situtypes was substantially better able than conventional psychopathology syndromes (attention‐deficit hyperactivity, oppositional defiance, etc.) to forecast later academic achievement. Implications for informing motivation and intervention are discussed. © 2005 Wiley Periodicals, Inc. Psychol Schs 42: 121–136, 2005.
A contextual approach to the assessment of social skills: Identifying meaningful behaviors for social competence
Authors: Warnes Emily D. , Sheridan Susan M. , Geske Jenenne , Warnes William A.
Published: January 2005

An exploratory study was conducted which assessed behaviors that characterize social competence in the second and fifth grades. A contextual approach was used to gather information from second‐ and fifth‐grade children and their parents and teachers regarding the behaviors they perceived to be important for getting along well with peers. Data were gathered from children through structured interviews with the researcher. Parents and teachers provided information through open‐ended paper‐pencil surveys. Qualitative methodology was used to analyze the data in this study. Specifically, a three‐stage coding process derived from grounded theory was utilized (A. Strauss & J. Corbin, 1998). Triangulation, a technique common to qualitative research whereby multiple sources are used to verify themes identified from data, also was used throughout the coding process to enhance standards of rigor (J.W. Creswell, 1998). Results indicated substantial overlap among the types of behaviors reported by children, parents, and teachers in both grades. Likewise, a number of noteworthy similarities and differences were found among second‐ and fifth‐grade sources. Findings are discussed in terms of their implications for social skills assessment and intervention. Limitations and directions for future research also are discussed. © 2005 Wiley Periodicals, Inc. Psychol Schs 42: 173–187, 2005.
Development of the California school climate and safety survey‐short form
Authors: Furlong Michael J. , Greif Jennifer L. , Bates Michael P. , Whipple Angela D. , Jimenez Terese C. , Morrison Richard
Published: January 2005

Planning is essential to creating safe schools and it is required by the Federal No Child Left Behind legislation (U.S. Department of Education, 2004) and implemented via district local education action plans. The implementation of these plans involves continuous monitoring and reevaluation of information pertinent to each campus. As such, this process is facilitated by the availability of measures that are simple to administer, inexpensive, and whose psychometric properties have been evaluated. The California School Climate and Safety Survey (CSCSS), originally developed by M.J. Furlong, R. Morrison, and S. Boles (1991), was specifically developed for these purposes. The CSCSS is a student self‐report questionnaire created to measure general school climate and personal safety‐related experiences. In this article, we present the results of an evaluation of the CSCSS including exploratory and confirmatory factor analyses. These analyses reduced the original CSCSS research version from 102 items to 54 items. The psychometric properties of this CSCSS‐SF (Short Form) are presented. © 2005 Wiley Periodicals, Inc. Psychol Schs 42: 137–149, 2005.
Consequences of proton transfer in guanidine
Authors: Raczyńska Ewa D. , Cyrański Michał K. , Gutowski Maciej , Rak Janusz , Gal Jean‐François , Maria Pierre‐Charles , Darowska Małgorzata , Duczmal Kinga
Published: January 2005

Consequences of proton‐transfer reactions in guanidine in the solid state, solution and gas phase are discussed. Y‐delocalization, resonance and symmetry strongly influence the basicity of guanidine in the gas phase. These effects are, however, insufficient to explain the basicity of guanidine which in aqueous solution is stronger than that of trisubstituted alkylamines and proton sponge (DMAN). The intrinsic (gas‐phase) basicity of guanidine is close to that of triethylamine. The large difference between the basicities of amines and guanidine in solution is attributed to the important role played by effects such as polarizability and internal and external solvation. Copyright © 2003 John Wiley & Sons, Ltd.
Semi‐empirical studies of substituent effects on the ionization of bicyclooctane carboxylic acids and quinuclidines
Authors: Diez y Riega Helena , Rincón Luis , Almeida Rafael
Published: January 2005

Semiempirical AM1 calculations were performed for a representative series of 4‐substituted bicyclooctane carboxylic acids and quinuclidines. It was found that the Hammett constant, σI, and the Swain and Lupton field constant, F, correlate linearly with the differences in the heat of formation of isodesmic reactions. These constants also correlate with the charges on the acid moiety of the bicyclooctane acids and their anions, and with the hydrogen net charge on the protonated quinuclidines. For all cases, the NO2 was the poorest correlated substituent. Copyright © 2003 John Wiley & Sons, Ltd.
Facile synthesis, characterization, and potential applications of two kinds of polymeric pH indicators: Phenolphthalein formaldehyde and o‐cresolphthalein formaldehyde
Authors: Liu Zhihong , Liu Junfeng , Chen Tianlu
Published: January 2005

Two kinds of applicable polymeric pH indicators were synthesized by the reaction of phenolphthalein and o‐cresolphthalein with formaldehyde under alkaline conditions by a one‐pot method. The synthesized products were fully characterized with Fourier transform infrared, 1H NMR, ultraviolet–visible spectroscopy, and gel permeation chromatography. The results indicated that the reaction was a typical phenol formaldehyde reaction. The dosage of formaldehyde and the reaction time were well controlled to obtain soluble polymers, instead of crosslinked products. The polymeric‐pH‐indicator‐immobilized poly(vinyl alcohol) (PVA) membranes were easily fabricated and had good long‐term stability under highly basic conditions and a fast equilibrium response. Moreover, the phenolphthalein formaldehyde immobilized PVA membrane had a linear response from pH 10.0 to 14.0, and so it has promise as a optical transducer for high pH value determinations. The o‐cresolphthalein formaldehyde immobilized PVA membrane had a nonlinear response from pH 9.0 to 13.0. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1019–1027, 2005
Conformational behavior of nylon 6 in mixed solvents
Authors: Baloch Musa Kaleem , Nawaz Mohsan
Published: January 2005

The intrinsic viscosity [η], Huggins constant (KH), laser light scattering, UV and IR measurements of Nylon 6 are made in m‐cresol and its mixture with 1,4‐dioxane at 20–60 °C. The intrinsic viscosity, Rg, A2, (2)1/2 (calculated from viscosity data), RH, and UV absorbance initially increase and then decrease with the rise in 1,4‐dioxane contents. The KH and the transmittance of OH group in IR spectra show an opposite trend to that of [η]. The dielectric constant calculated from the refractive index of the solvent (m‐cresol with 1,4‐dioxane) and polymer solution shows a continuous decrease with the amount of 1,4‐dioxane. Activation energy shows a minimum while linear expansion coefficient (α3) maximum with the addition of 1,4‐dioxane. Change in [η], KH, and other characteristics of the polymer solutions with alterations in solvent composition and temperature are the result of variation in the thermodynamic quality of the solvent, its selective adsorption, hydrogen bonding, and conformational transitions. It has been concluded that the addition of 1,4‐dioxane first enhances the quality of the solvent, encourages hydrogen bonding, and specific adsorption, and then deteriorates, bringing conformational transitions in the polymer molecules. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 534–541, 2005
Synthesis of poly(urethane urea) by in situ polymerization inside stone
Authors: Cocca M. , D'Arienzo L. , D'Orazio L. , Gentile G. , Martuscelli E.
Published: January 2005

The first synthesis of poly(urethane urea) by in situ polymerization inside stone was successfully carried out. Poly(propylene glycol), isophorondiisocyanate, and a catalyst [tin(II) ethyl hexanoate, aluminum acetylacetonate, or zirconium acetylacetonate] were mixed with acetone in petri dishes, and tuff samples were placed in the dishes at room temperature. The effects of the comonomer ratio, catalyst, and catalyst concentration on the chemical structure of the synthesized poly(urethane urea) were investigated. The poly(urethane urea) distribution inside the tuff and the related morphology were also analyzed, as well as the reversibility of the performed treatments. Finally, the effects of the in situ polymerization polymer on the properties of the stone, such as water capillary absorption and permeability to water vapor, were assessed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 542–552, 2005
Crystallization kinetics and melting behavior of syndiotactic 1,2‐polybutadiene
Authors: Ren Minqiao , Chen Qingyong , Song Jianbin , Zhang Huiliang , Sun Xiaohong , Mo Zhishen , Zhang Hongfang , Zhang Xuequan , Jiang Liansheng
Published: January 2005

Differential scanning calorimetry was used to investigate the isothermal crystallization, subsequent melting behavior, and nonisothermal crystallization of syndiotactic 1,2‐polybutadiene (st‐1,2‐PB) produced with an iron‐based catalyst system. The isothermal crystallization of two fractions was analyzed according to the Avrami equation. The morphology of the crystallite was observed with polarized optical microscopy. Double melting peaks were observed for the samples isothermally crystallized at 125–155 °C. The low‐temperature melting peak, which appeared approximately 5 °C above the crystallization temperature, was attributed to the melting of imperfect crystals formed by the less stereoregular fraction. The high‐temperature melting peak was associated with the melting of perfect crystals formed by the stereoregular fraction. With the Hoffman–Weeks approach, the value of the equilibrium melting temperature was derived. During the nonisothermal crystallization, the Ozawa method was limited in obtaining the kinetic parameters of st‐1,2‐PB. A new method that combined the Ozawa method and the Avrami method was employed to analyze the nonisothermal crystallization of st‐1,2‐PB. The activation energies of crystallization under nonisothermal conditions were calculated. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 553–561, 2005
Kinetics of fluid spreading on viscoelastic substrates
Authors: Kaneko Daisaku , Gong Jian Ping , Zrínyi Miklós , Osada Yoshihito
Published: January 2005

The spontaneous spreading of non‐film‐forming fluids on the surfaces of aqueous solutions of poly(2‐acrylamido‐2‐methyl‐propanesulfonic acid) and its chemically crosslinked gels was studied. The experiments were performed in the same concentration range for the solutions and gels, far above the overlap concentration of the polymer solutions. The leading edge (R) of the spreading liquid showed a power‐law behavior with time t: R = K(t + c)α, where α is the spreading exponent and K is the spreading prefactor. α and K were significantly different for the polymer solutions and gels. Here c was a constant that depended on the initial conditions of the spreading liquids. Depending on the polymer concentration, α of the polymer solutions varied between the upper (3/4) and lower (1/10) theoretical limits for viscose liquids and solids, respectively. This indicates that no universal scaling law exists for the spreading process on viscoelastic surfaces. On the polymer gels, which were elastic substrates, universal values of α could be observed and could be expressed as R ∝ (t + c)0.45 and R ∝ (t + c)0.3 for miscible and nonmiscible spreading liquids, respectively; they showed no dependence on the polymer concentration or network mesh size. This shows that on an elastic gel surface, spreading is more or less similar to that on a solid surface. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 562–572, 2005
Reliability of the lung‐to‐head ratio in predicting outcome and neonatal ventilation parameters in fetuses with congenital diaphragmatic hernia
Authors: Heling K. S. , Wauer R. R. , Hammer H. , Bollmann R. , Chaoui R.
Published: January 2005

Objectives

The ratio of the lung area (on the contralateral side of the hernia) to the head circumference, the lung‐to‐head ratio (LHR), has been proposed as a reliable tool in the assessment of the prognosis of congenital diaphragmatic hernia (CDH). An LHR < 0.6 has been associated with poor outcome whereas one > 1.4 has been associated with survival. We aimed to analyze the role of LHR in predicting fetal outcome and ventilation parameters in cases of isolated CDH in our center.

Methods

During the 40‐month study period, 22 fetuses with an isolated CDH were delivered alive under optimized conditions at our perinatal center. LHR was measured at the time of diagnosis (median, 27 weeks' gestation). In addition to survival, postnatal ventilation parameters including pCO2, pO2, inspiratory O2 partial pressure, inspiratory pressure and oxygenation index were determined, as was the occurrence of pulmonary hypertension.

Results

The overall survival rate was 59%. The LHR was not able to predict fetal outcome reliably. There was no correlation between the liver herniation, LHR and fetal outcome. The prenatally determined lung size reflected in the LHR did not show any significant association with individual ventilation parameters. Eleven of 17 infants examined had signs of pulmonary hypertension and the LHR did not predict this condition.

Conclusion

Our study cannot support the optimistic results reported by other groups on the use of LHR as a reliable predictor of outcome in fetuses with CDH. The LHR, as a reflection of lung size, correlates neither with survival patterns nor with various postnatal ventilation parameters. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
Quantitative determination of major systematics in synchrotron x‐ray experiments: seeing through harmonic components
Authors: Tran C. Q. , Barnea Z. , de Jonge M. D. , Dhal B. B. , Paterson D. , Cookson D. J. , Chantler C. T.
Published: January 2005

In line with an ongoing programme to determine accurately x‐ray attenuation coefficients, we have developed a method for the quantitative determination of the effect on experimental results of monochromator harmonic components in a synchrotron beam. The technique can be adapted to suit a wide variety of experiments, and is of particular interest because it determines the effect of the harmonic components directly. This avoids the necessity for modelling and is therefore robust. Results of a direct determination of the effect of harmonic components illustrate the power of the technique. We extended the technique to quantify the effects of dark current‐induced errors. Copyright © 2003 John Wiley & Sons, Ltd.
Response of coccinellids to their aphid prey at different spatial scales
Authors: Schellhorn Nancy A. , Andow David A.
Published: January 2005

Predators that have an increasing numerical response for aggregation, attack and oviposition to increasing prey density are thought to be ideal for biological control. However density‐dependent processes are infrequently detected and explanations include differences in the scales at which observations are made, behavioral differences among species, and habitat features. We examined the aggregation of four species of colonizing adult coccinellids to varying prey densities at two spatial scales in a maize system. Three of the species, Adalia bipunctata, Hippodamia tredecimpunctata, and Hippodamia convergens, responded to aphid abundance at the plant scale, and one species, Coleomegilla maculata, responded to the average aphid density at the plot (10×10 m) scale. In addition, H. convergens responded to individual plants with high aphid abundance in those plots with many plants of high aphid abundance. These results suggests that C. maculata (and possibly H. convergens) may be better able to colonize fields before aphid populations reach high levels, whereas A. bipunctata and H. tredecimpunctata may only be able to respond to high aphid abundance at the plant scale. This study suggests that spatial scale can affect predator–prey dynamics in a species‐specific manner. However, the differences among coccinellid species in the community appear to be complementary, potentially contributing to greater aphid suppression.
Growth and competition between seedlings of an invasive plantation tree, Acacia mangium, and those of a native Borneo heath‐forest species, Melastoma beccarianum
Authors: Osunkoya Olusegun O. , Othman Farah E. , Kahar Rafhiah S.
Published: January 2005

An introduced plantation tree species, Acacia mangium Willd., is becoming invasive in the Brunei region of Borneo. To examine its invasive potential, a greenhouse, additive series experiment (target–neighbour) involving seedlings of A. mangium and those of a common native heath‐forest (kerangas), Melastoma beccarianum Cogn. was carried out under low and high light regimes in intra‐ and interspecific combinations over a 6‐month period. Significant variations in growth parameters (other than biomass allocation patterns) existed amongst seedlings from different treatments. A major part of this variation in growth could be attributed to the main factors of target species, neighbour species, and competition (seedling density). For the growth variables examined, the target–species response was not consistent across light regimes. Under high light conditions, Acacia was the better competitor; the Lotka‐Volterra competition coefficient effect of Melastoma on Acacia was lower (α=0.30) than the effect of Acacia on Melastoma (β=0.54). However, the reverse occurred under low light conditions with Melastoma gaining the upper hand (α=1.45 and β=0.44). These results show that light (and hence disturbance) can strongly influence the pattern and intensity of both intra‐ and interspecific competition between invasive and local flora species. Relatively intact forest is unlikely to be invaded by Acacia trees (as they are poor competitors under this scenario). On the other hand, the Acacia trees can easily invade disturbed forests, especially those prone to recurring drought and fire, and over time convert the habitats to nearly monospecific stands, as is presently being observed in Brunei.
Coping style and psychological health among adolescent prisoners: a study of young and juvenile offenders
Authors: Ireland Jane L. , Boustead Rebecca , Ireland Carol A.
Published: January 2005

The current study explores the role of coping styles as a predictor of poor psychological health among adolescent offenders. It presents the first study to compare young and juvenile offenders. Two hundred and three male offenders took part: 108 young (18–21 years) and 95 juvenile (15–17 years) offenders. All completed the General Health Questionnaire (GHQ‐28) and a revised version of the Coping Styles Questionnaire (CSQ‐3). Young offenders reported using emotional, avoidant and detached coping styles more than juveniles. They also reported more overall psychological distress than juveniles, with a trend to report increased depression, anxiety and insomnia. For both young and juvenile offenders, emotional coping predicted increased psychological distress. This was consistent across different symptoms (i.e. somatic, anxiety and insomnia, social dysfunction and severe depression). For young offenders, rational coping predicted a decrease in overall distress and was found across all symptoms. For juveniles, although detached coping predicted a decrease in overall psychological distress, across symptoms it only predicted social dysfunction. Increased rational coping was also found to predict decreased depression for juveniles. The study highlights differences between young and juvenile offenders regarding coping styles and how this relates to psychological distress. It highlights the complexities of trying to understand the coping‐health relationship in a prison setting and asks if such settings are increasing the potential for adolescents to over‐use coping styles that may not be the most effective.
Brief report: Acceptance of physical violence (APV) among adolescents in a Norwegian normal sample; statistical description of the assessment
Authors: Naevdal F.
Published: January 2005

The article presents a psychometric description of 11 statements related to use of physical violence. The items were tested in a normal sample (, age: 15–16) from urban and rural areas in Western Norway. The internal reliability was , and the factor analysis resulted in two factors. Boys had higher mean scores than girls. Self‐reported violence was predicted by acceptance of physical violence.
The tRNA aminoacylation co‐factor Arc1p is excluded from the nucleus by an Xpo1p‐dependent mechanism
Authors: Galani Kyriaki , Hurt Ed , Simos George
Published: January 2005

Arc1p, a yeast tRNA‐binding protein, forms a complex with the aminoacyl‐tRNA synthetases, methionyl tRNA synthetase (MetRS) and glutamyl tRNA synthetase (GluRS). Although this complex localizes normally in the cytoplasm, in the absence of Arc1p the two free synthetases are also found inside the nucleus. In this work, in order to localize free Arc1 we abolished complex assembly by deleting the appended domains from both MetRS and GluRS. Surprisingly, free Arc1p remained cytoplasmic even when fitted with a strong nuclear localization signal (NLS). However, NLS‐Arc1p accumulated in the nucleus when Xpo1/Crm1, the export receptor for NES‐containing cargo proteins, was mutated. Thus, the cytoplasmic location of Arc1p is maintained by Xpo1p‐dependent nuclear export and Arc1p could act as an adapter in the nucleocytoplasmic trafficking of tRNA and/or the tRNA‐aminoacylation machinery.
Msp1p is an intermembrane space dynamin‐related protein that mediates mitochondrial fusion in a Dnm1p‐dependent manner in S. pombe
Authors: Guillou Emmanuelle , Bousquet Céline , Daloyau Marlène , Emorine Laurent J. , Belenguer Pascale
Published: January 2005

Mitochondrial morphology is controlled by large GTPases, such as Msp1p, whose action on mitochondrial membranes is not yet understood. The sub‐mitochondrial localization of Msp1p, the subject of ongoing controversies, was found to be within the intermembrane space. Overexpression of Msp1p led to aggregation of the mitochondrial network, while its downregulation resulted in fragmentation of this network. Mutations affecting the integrity of the Msp1p GTPase function had a dominant phenotype and induced mitochondrial fragmentation followed by mitochondrial DNA loss and cell death. These effects were not observed in cells deleted for Dnm1p, an actor in mitochondrial fission, suggesting that Msp1p is involved in the fusion of mitochondria.
Infection resistance of unreamed solid, hollow slotted and cannulated intramedullary nails: An in‐vivo experimental comparison
Authors: Horn J. , Schlegel U. , Krettek C. , Ito K.
Published: January 2005

Infection continues to be a problematic complication of fracture treatment, particularly in severe open fractures. The implant design and material as well as implantation technique play an important role in the pathogenesis of local infection. The aim of our study was to determine if the local resistance to infection of a cannulated IM nail is less than that of a solid nail and more similar to that of a hollow nail. In 65 female White Zealand rabbits, the intramedullary cavity was inoculated with matching concentrations of Staphylococcus aureus, and one of the three nails was inserted. The solid nail had a greater than twofold higher resistance to infection (23%) compared to that of the other two nails (hollow, 65%; cannulated, 61%) which was statistically significant (p < 0.2). No difference in infection resistance was detected between the hollow slotted and cannulated nail designs (p = 1). Although these experimental results may be clinically considered, direct extrapolation to clinical infection rates is ill advised. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Enrichment of HFSE in chlorite‐harzburgite produced by high‐pressure dehydration of antigorite‐serpentinite: Implications for subduction magmatism
Authors: Garrido Carlos J. , López Sánchez‐Vizcaíno Vicente , Gómez‐Pugnaire María Teresa , Trommsdorff Volkmar , Alard Olivier , Bodinier Jean‐Louis , Godard Marguerite
Published: January 2005

Depletion of high‐field‐strength trace elements (HFSE) relative to normal mid‐ocean basalts (N‐MORB) is the most distinctive geochemical fingerprint of subduction magmatism. Proposed hypotheses advocate that this “subduction” signature is acquired during melting and/or fluid transfer either in the mantle wedge or in the crust of the subducting oceanic plate. Here we provide field‐based and geochemical evidence showing that high‐pressure dehydration of antigorite‐serpentinite produces chlorite‐harzburgite relatively enriched in HFSE due to the stabilization of F‐OH‐Ti‐clinohumite intergrowths with prograde olivine. Available experimental data indicate that in hydrated, intermediate to warm subduction zones, clinohumite‐olivine intergrowths can be stable in prograde chlorite‐harzburgite olivine at subarc depths. In these settings, deserpentinization may act as a source of fluids leaching large‐ion lithophile elements (LILE), Pb, and Sr from the overlying crust and sediments on their way up to the mantle wedge. Stabilization of chlorite‐harzburgites with clinohumite‐olivine intergrowths in the mantle wedge, on the other hand, acts as a sink of HFSE by selectively fractionating them from other incompatible trace elements in fluids emanating from the slab. Resulting arc fluids in equilibrium with wedge chlorite‐harzburgite are strongly depleted in HFSE and transfer this depletion to the overlying hot mantle wedge, where subduction magmas are generated.
The October 28, 2003 extreme EUV solar flare and resultant extreme ionospheric effects: Comparison to other Halloween events and the Bastille Day event
Authors: Tsurutani B. T. , Judge D. L. , Guarnieri F. L. , Gangopadhyay P. , Jones A. R. , Nuttall J. , Zambon G. A. , Didkovsky L. , Mannucci A. J. , Iijima B. , Meier R. R. , Immel T. J. , Woods T. N. , Prasad S. , Floyd L. , Huba J. , Solomon S. C. , Straus P. , Viereck R.
Published: January 2005

Some of the most intense solar flares measured in 0.1 to 0.8 nm x‐rays in recent history occurred near the end of 2003. The Nov 4 event is the largest in the NOAA records (X28) and the Oct 28 flare was the fourth most intense (X17). The Oct 29 flare was class X7. These flares are compared and contrasted to the July 14, 2000 Bastille Day (X10) event using the SOHO SEM 26.0 to 34.0 nm EUV and TIMED SEE 0.1–194 nm data. High time resolution, ∼30s ground‐base GPS data and the GUVI FUV dayglow data are used to examine the flare‐ionosphere relationship. In the 26.0 to 34.0 nm wavelength range, the Oct 28 flare is found to have a peak intensity greater than twice that of the Nov 4 flare, indicating strong spectral variability from flare‐to‐flare. Solar absorption of the EUV portion of the Nov 4 limb event is a possible cause. The dayside ionosphere responds dramatically (∼2.5 min 1/e rise time) to the x‐ray and EUV input by an abrupt increase in total electron content (TEC). The Oct 28 TEC ionospheric peak enhancement at the subsolar point is ∼25 TECU (25 × 1012 electrons/cm2) or 30% above background. In comparison, the Nov 4, Oct 29 and the Bastille Day events have ∼5–7 TECU peak enhancements above background. The Oct 28 TEC enhancement lasts ∼3 hrs, far longer than the flare duration. This latter ionospheric feature is consistent with increased electron production in the middle altitude ionosphere, where recombination rates are low. It is the EUV portion of the flare spectrum that is responsible for photoionization of this region. Further modeling will be necessary to fully understand the detailed physics and chemistry of flare‐ionosphere coupling.
Electron pressure effects on driven auroral Alfvén waves
Authors: Vedin Jörgen , Rönnmark Kjell
Published: January 2005

Fluid models for the auroral electron acceleration processes have almost exclusively been derived by assuming cold or isothermal electrons. The consequences of these assumptions have never been thoroughly analyzed. In this study we compare results from an isothermal simulation with those obtained when the pressure is calculated from a double adiabatic approximation and from stationary kinetic theory. We find that the reflection of shear Alfvén waves, as well as the current‐voltage relation, is very sensitive to the description of the electron pressure variations. Using pressures calculated from steady‐state kinetic theory, we find that driven shear Alfvén waves can build up auroral currents and fields that are consistent with a linear current‐voltage relation.