bluuebunny/crossref_metadata_2025 huggingface dataset:
Outcomes Following Mindfulness-Based Cognitive Therapy in a Heterogeneous Sample of Adult Outpatients
Authors: Ree Melissa J. , Craigie Mark A.
Published: July 2007

Research on mindfulness-based cognitive therapy (MBCT; Segal, Williams, & Teasdale, 2002a) has supported the effectiveness of this approach for use with preventing relapse in recurrent depression. This study evaluated the use of MBCT in a heterogeneous sample of 26 psychiatric outpatients with mood and/or anxiety disorders. Results from both completer and intent to treat analyses showed that MBCT was associated with statistically significant improvements in depression, anxiety, stress, and insomnia symptoms. Rates of clinically significant improvement were comparable with effectiveness studies of cognitive behaviour therapy and mindfulness-based stress reduction in heterogeneous samples. It is concluded that MBCT may be of value for a range of psychological presentations, administered in heterogeneous groups. Future, controlled, research is required to further evaluate this conclusion and to investigate mechanisms of change.
Book Reviews
Authors: Rabine Leslie W.
Published: July 2007

Fashioning Africa: Power and the Politics of Dress. Jean Allman, ed. Bloomington: Indiana University Press, 2004. vii + 247 pp., photographs, index.
Book Reviews
Authors: VAN DER GEEST SJAAK
Published: July 2007

Pharmaceutical Reason: Knowledge and Value in Global Psychiatry. Andrew Lakoff. Cambridge: Cambridge University Press, 2005. x + 206 pp., references, index.
Book Reviews
Authors: HITCHNER SARAH
Published: July 2007

Wild Profusion: Biodiversity Conservation in an Indonesian Archipelago. Celia Lowe. Princeton: Princeton University Press, 2006. vii + 196 pp., map, photographs, tables, references, index.
Book Reviews
Authors: LILLIOS KATINA T.
Published: July 2007

Interacting with the Dead: Perspectives on Mortuary Archaeology for the New Millennium. Gordon F. M. Rakita, Jane E. Buikstro, Lane A. Beck, Sloan R. Williams, eds. Gainesville: University Press of Florida, 2005. xii + 390 pp., maps, photographs, tables, references, index.
Book Reviews
Authors: CARRIER JAMES G.
Published: July 2007

Out of the Pits: Traders and Technology from Chicago to London. Caitlin Zaloom. Chicago: University of Chicago Press, 2006. xii + 224 pp., photographs, references, index.
Ways of reading as religious power in print globalization
Authors: KIRSCH THOMAS G.
Published: July 2007

In this article, I address issues of power with regard to religious print media distributed worldwide. I show that mission societies seek to ensure a homogenous interpretation of their publications by making them “obligatory passage points” for socioreligious advancement and standardizing literacy practices. Once successfully established, networks created through religious print media evolve as a twofold process in which the construction of power by media distributors and their audiences' seeking of empowerment form an integrated whole. In this trajectory, literacy practices bridge local and global realms by enabling extensive religious networking based on the shared use of print media.
Differences in Response to a Hepatitis B Vaccine Booster Dose Among Alaskan Children and Adolescents Vaccinated During Infancy
Authors: Samandari Taraz , Fiore Anthony E. , Negus Susan , Williams James L. , Kuhnert Wendi , McMahon Brian J. , Bell Beth P.
Published: July 2007

BACKGROUND. The duration of protection provided by hepatitis B vaccination is unknown, but the presence of immune memory can be evaluated indirectly by measuring the immune response to a booster dose of vaccine.

METHODS. Participants included 74 adolescents (aged 11.7–14.9 years) who had received a plasma-derived 3-dose primary vaccine series and 138 adolescents (aged 10.0–14.7 years) and 166 children (aged 5.0–7.0 years) who received a recombinant 3-dose primary vaccine series. All were born to hepatitis B surface antigen–negative mothers and had received the first dose of hepatitis B vaccine within 7 days of birth. The proportion of participants with serologic evidence of protective immunity (antibody to hepatitis B surface antigen ≥10 mIU/mL) at baseline (prebooster), the proportion who developed an anamnestic response (increase to ≥10 mIU/mL or at or more than fourfold increase in antibody to hepatitis B surface antigen to >10 mIU/mL), and the geometric mean concentration by 1, 2, and 4 weeks after a 5-μg recombinant vaccine booster dose were determined.

RESULTS. No participant had evidence of chronic hepatitis B virus infection. Overall, 99% of the group of children who received recombinant hepatitis B vaccine, 83% of the group of adolescents who received recombinant hepatitis B vaccine, and 69% of the group of adolescents who received the plasma-derived vaccine had an anamnestic response to a booster dose; among responders, the geometric mean concentration at 2 weeks postbooster was 3360 and 128 mIU/mL among adolescents who received plasma-derived vaccine with antibodies to hepatitis B surface antigen ≥10 and <10 mIU/mL at baseline, respectively, compared with 1283 and 369 mIU/mL among adolescents who received recombinant hepatitis B vaccine and 5091 and 696 mIU/mL for children who received recombinant hepatitis B vaccine. The anamnestic response rate at 2 weeks postbooster among participants with antibodies to hepatitis B surface antigen <10 mIU/mL at baseline was inversely associated with age; 97% of 5-year-olds responded compared with 60% of 14-year-olds.

CONCLUSIONS. Although most participants responded to a booster dose of hepatitis B vaccine, the significance of the increased proportion of nonresponses among older adolescents might indicate waning immune memory.
A PCR-based expression signature of malignancy in follicular thyroid tumors
Authors: Foukakis Theodoros , Gusnanto Arief , Au Amy YM , Höög Anders , Lui Weng-Onn , Larsson Catharina , Wallin Göran , Zedenius Jan
Published: July 2007

The diagnosis of follicular thyroid carcinoma (FTC) in the absence of metastasis can only be established postoperatively. Moreover, high-risk FTCs are often not identifiable at the time of diagnosis. In this study, we aimed to identify transcriptional markers of malignancy and high-risk disease in follicular thyroid tumors. The expression levels of 26 potential markers of malignancy were determined in a panel of 75 follicular thyroid tumors by a TaqMan quantitative RT-PCR approach. Logistic regression analysis (LRA) was used for gene selection and generation of diagnostic and prognostic algorithms. An algorithm based on the expression levels of five genes (TERT, TFF3, PPARγ, CITED1, and EGR2) could effectively predict high-risk disease with a specificity of 98.5%. The metastatic potential could be predicted in all four cases with apparently benign or minimally invasive (MI) disease at the time of diagnosis, but poor long-term outcome. In addition, a second model was produced by implementing two genes (TERT and TFF3), which was able to distinguish adenomas from de facto carcinomas. When this model was tested in an independent series of atypical adenomas (AFTA) and MI-FTCs, 16 out of 17 AFTAs were classified as ‘benign’, while MI-FTCs with vascular invasion (sometimes referred to as ‘moderately invasive’) and/or large tumor size tended to classify in the ‘malignant’ group. The reported models can be the foundation for the development of reliable preoperative diagnostic and prognostic tests that can guide the therapeutic approach of follicular thyroid neoplasms with indeterminate cytology.
Prognostic relevance of increased Rac GTPase expression in prostate carcinomas
Authors: Engers R , Ziegler S , Mueller M , Walter A , Willers R , Gabbert H E
Published: July 2007

Rac proteins of the Rho-like GTPase family, including the ubiquitous Rac1, the hematopoiesis-specific Rac2, and the least-characterized Rac3 play a major role in oncogenic transformation, tumor invasion and metastasis. However, the prognostic relevance of Rac expression in human tumors has not been investigated yet. In the present study, Rac protein expression was analyzed in benign secretory epithelium, high-grade prostatic intraepithelium neoplasia (HG-PIN), and prostate carcinomas of 60 R0-resected radical prostatectomy specimens by semiquantitative immunohistochemistry. Thus, Rac proteins were significantly strongly expressed in HG-PIN (P < 0.001) and prostate carcinomas (P < 0.001) when compared with benign secretory epithelium. Accordingly, all tumor tissues analyzed by isoform-specific real-time PCR (n = 7) exhibited significantly higher RNA expression levels of Rac (i.e. sum of Rac1 and Rac3 expression levels) than the respective benign counterparts (P = 0.018) and this appeared to result mainly from increased expression of the Rac3 isoform as verified by immunoblotting. Univariate analyses showed statistically significant associations of increased Rac protein expression in prostate cancer (P = 0.045), preoperative prostate-specific antigen levels (P = 0.044), pT stage (P = 0.002), and Gleason score (P = 0.001) with decreased disease-free survival (DFS). This prognostic effect of increased protein expression of Rac remained significant even in a multivariate analysis including all these four factors (relative risk = 3.22, 95% confidence interval = 1.04–10.00; P = 0.043). In conclusion, our data suggest that increased Rac protein expression in prostate cancer relative to the corresponding benign secretory epithelium is an independent predictor of decreased DFS and appears to result mainly from increased expression of the Rac3 isoform.
Candidate gene mutation analysis in bilateral adrenal pheochromocytoma and sympathetic paraganglioma
Authors: Korpershoek Esther , Petri Bart-Jeroen , van Nederveen Francien H , Dinjens Winand N M , Verhofstad Albert A , de Herder Wouter W , Schmid Sonja , Perren Aurel , Komminoth Paul , de Krijger Ronald R
Published: July 2007

Pheochromocytomas (PCCs) are rare tumors that arise from chromaffin tissue in the adrenal medulla, but can also occur in the abdomen outside the adrenals and are then called sympathetic paragangliomas (sPGLs). According to the literature, between 15 and 25% of apparently sporadic adrenal PCC and sPGL are caused by germline mutations in RET, von Hippel–Lindau disease (VHL), succinate dehydrogenase subunit B (SDHB), or subunit D SDHD. However, few studies have addressed the mutationfrequency of these candidate genes in selected subgroups of PCC andsPGL, such as bilateral adrenal PCC or extra-adrenal sPGL, and none have looked at somatic mutations by analyzing tumor tissue. Therefore, we have investigated the occurrence of germline and somatic mutations in RET, VHL, SDHB, and SDHD in comparatively large series of bilateral adrenal PCC (n = 33 patients) and sPGL (n = 26 patients), with the aim of determining the mutation frequency of each of these genes and to establish a genetic testing algorithm. Twenty-one RET, two VHL germline, and one SDHD mutations were found in the patients with bilateral adrenal PCC. In sPGL, one novel SDHB germline and one novel SDHB somatic mutation were observed. In addition, two SDHD germline mutations were found. We conclude that germline RET mutations are predominantly found in bilateral PCC, and that somatic and germline SDHB and SDHD mutations usually occur in sPGL, which has practical consequences for genetic testing algorithms. We suggest that sequential mutation analysis should be directed first at RET, followed by VHL and SDHD for patients with bilateral adrenal PCC at diagnosis, and at SDHB and SDHD for patients with sPGL.
Prolactin upregulates sphingosine kinase-1 expression and activity in the human breast cancer cell line MCF7 and triggers enhanced proliferation and migration
Authors: Döll Frauke , Pfeilschifter Josef , Huwiler Andrea
Published: July 2007

Sphingosine kinases (SK) catalyze the formation of sphingosine-1-phosphate (S1P) which plays a crucial role in cell growth and survival. Here, we show that prolactin (PRL) biphasically activates the SK-1, but not the SK-2 subtype, in the breast adenocarcinoma cell-line MCF7. A first peak occurs after minutes of stimulation and is followed by a second delayed activation after hours of stimulation. A similar biphasic effect on SK-1 activity is seen for 17β-estradiol (E2). The delayed activation of SK-1 derives from an upregulated mRNA and protein expression and is due to increased SK-1 promoter activity and mechanistically involves STAT5 activation as well as protein kinase C and the classical mitogen-activated protein kinases. Furthermore, glucocorticoids also block both hormone-induced SK-1 expression and activity. Functionally, long-term stimulation of MCF7 cells with PRL or E2 is well known to trigger increased cell proliferation and migration. Both hormone-induced cell responses critically involve SK-1 activation since the depletion of SK-1, but not SK-2, by siRNA transfection abolishes the hormone-induced cell proliferation and migration. In summary, our data show that PRL and E2 cause a pronounced delayed SK-1 activation which is due to increased gene transcription, and critically determines the capability of cells to grow and move. Thus, the SK-1 may represent a novel attractive target for anti-tumor therapy.
Adipokines as endocrine, paracrine, and autocrine factors in breast cancer risk and progression
Authors: Vona-Davis Linda , Rose David P
Published: July 2007

Adipokines (leptin, adiponectin, and hepatocyte growth factor (HGF)) secreted from adipose tissue have come to be recognized for their contribution to the mechanisms by which obesity and related metabolic disorders influence breast cancer risk. In this review, we discuss the direct and indirect effects of these protein factors on the biological and clinical aspects of breast cancer biology, and emphasize their distinctive modes of action through endocrine-, paracrine-, and autocrine-mediated pathways. The stimulatory effects of leptin on breast cancer growth were considered to occur primarily via activation of the estrogen receptor; however, new evidence suggests that leptin may be acting on downstream cell signaling pathways in both estrogen-dependent and -independent cell types. Another secretory adipokine, HGF, may act largely not only to promote tumor cell invasion, but also to enhance tumor growth indirectly by stimulating angiogenesis. In contrast, adiponectin, an endogenous insulin sensitizer, exerts a direct growth-inhibitory effect on tumor cells by downregulating cell proliferation and upregulating apoptosis, and also inhibits tumor-related angiogenesis.
Polymorphisms in the Janus kinase 2 (JAK)/signal transducer and activator of transcription (STAT) genes: putative association of the STAT gene region with familial breast cancer
Authors: Vaclavicek Annika , Bermejo Justo Lorenzo , Schmutzler Rita K , Sutter Christian , Wappenschmidt Barbara , Meindl Alfons , Kiechle Marion , Arnold Norbert , Weber Bernhard H F , Niederacher Dieter , Burwinkel Barbara , Bartram Claus R , Hemminki Kari , Försti Asta
Published: July 2007

The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway mediates the signals of a wide range of cytokines, growth factors and hormones. Thus, aberrant activation of the JAK/STAT pathway may predispose to malignancy due to deregulation of proliferation, differentiation or apoptosis. In this study, we investigated whether genetic variation in the JAK2 gene and the STAT gene region (STAT3, STAT5A and STAT5B) is associated with breast cancer (BC) risk. We carried out a case-control study using a German sample set with 441 familial, unrelated BC cases and 552 controls matched by age, ethnicity and geographical region. A second similar set (381 cases, 460 controls) was applied to validate the findings. Haplotypes in the JAK2 gene were not associated with the risk of BC. In the STAT gene region, the rare haplotype CAGCC containing the variant alleles of each single nucleotide polymorphism (SNP) was associated with an increased risk odds ratio (OR = 5.83, 95% confidence interval (CI) 1.51–26.28). According to Akaike’s information criterion, the best model to describe the relationship between the haplotypes and BC was based on the SNPs rs6503691 (STAT5B) and rs7211777 (STAT3). Carriers of the AC haplotype, which represents the variant alleles of both SNPs, were at an increased risk (OR = 1.41, 95% CI 1.09–1.82). A decreased risk was observed for carriers of the AT haplotype (OR = 0.60, 95% CI 0.38–0.94). Furthermore, individuals with the AC/GC diplotype were at a significantly increased risk (OR = 1.88, 95% CI 1.13–3.14). The observed genetic variation may also influence the inter-individual variation in response to STAT-signalling targeted therapy.
Endothelins and hypoxia-inducible factor in cancer
Authors: Grimshaw M J
Published: July 2007

The endothelin system is a family of three similar small peptides, two G-protein-coupled receptors and two proteinases. Endothelins have several physiological roles, notably in embryonic differentiation and vascular homeostasis. Numerous types of tumour express endothelins and their regulation is often aberrant when compared with the normal tissue from which the tumour arose. However, endothelin expression is tumour-type specific, and in some instances, expression of individual members of the endothelin system will be upregulated, while in other tumour types, they may be downregulated. Endothelins have numerous potential roles in tumours including modulating angiogenesis, inducing mitogenesis and invasion of tumour cells, and protecting cells from apoptosis. Expression of endothelins is controlled by the tumour microenvironment, whilst the endothelins themselves modify that environment; a case in point is that hypoxia stimulates endothelin expression via hypoxia-inducible factor (HIF)-1, while endothelins stabilise HIF-1 leading to expression of, for instance, vascular endothelial growth factor. This review highlights the potential roles of endothelins in various cancers and describes the pre-clinical and clinical progress that has been made in several tumour types – notably prostate, ovary, melanoma and breast cancer. The interactions between the endothelin network and HIF-1 are highlighted.
Analysis of Gene Expression during Brassica Seed Germination Using a Cross‐Species Microarray Platform
Authors: Hudson Matthew E. , Bruggink Tonko , Chang Sherman H. , Yu Wenjin , Han Bin , Wang Xun , van der Toorn Peter , Zhu Tong
Published: July 2007

We have developed an approach to facilitate the use of model organism microarrays in related, nonmodel organisms. We demonstrate the method by using Arabidopsis oligonucleotide microarrays to analyze gene expression in Brassica Probes with low hybridization signals to Brassica genomic DNA were excluded from the transcriptional analysis of an Arabidopsis microarray at the software level, forming a virtual Brassica microarray. We then performed an experiment on transcriptional responses during seed germination in Brassica using 17 886 homologous probesets of the virtual array where Brassica mRNA hybridization was detected. We subjected seed to hydration or priming (a step to improve germination vigor) and subsequent heating and drying treatments (steps to prolong shelf life of dried seed). Exploration of the microarray results indicated two likely expression patterns shared by many genes. One class of transcripts was strongly, globally, and irreversibly downregulated by priming, while other transcripts were induced, but often reversibly. Legacy seed‐storage protein messages were in the first class, and many protein synthesis components and some resource mobilization enzymes were in the second. We were able to validate our results by confirming transcriptional responses using reverse transcription polymerase chain reaction (RT–PCR).
Third Trimester Intrauterine Fetal Death Caused by Arterial Aneurysm of the Umbilical Cord
Authors: Weber Martin A. , Sau Ashis , Maxwell Darryl J. , Mounter Norman A. , Lucas Sebastian B. , Sebire Neil J.
Published: July 2007

Umbilical artery aneurysm (UAA) of the umbilical cord is an extremely rare lesion, with only 8 reported cases in the English-language literature; 7 of these were associated with significant fetal morbidity or mortality and 4 were associated with fetal trisomy 18. We report an additional case of UAA with normal karyotype that resulted in intrauterine growth restriction and fetal demise. It has been suggested that these aneurysms cause fetal hypoxia and intrauterine fetal death, either by compression of the umbilical vein or by acute kinking of the umbilical cord. Cytogenetic analysis should be performed in all cases diagnosed with this unusual lesion, and placental mosaicism for trisomy 18 should be excluded.
Primary Desmoplastic Small round Cell Tumor of the Kidney: A Case Report in a 14-Year-Old Girl with Molecular Confirmation
Authors: Collardeau-Frachon Sophie , Ranchère-Vince Dominique , Delattre Olivier , Hoarau Stelly , Thiesse Philippe , Dubois Rémi , Bergeron Christophe , Dijoud Frédérique , Bouvier Raymonde
Published: July 2007

We report a case of desmoplastic small round cell tumor (DSRCT) arising in the kidney of a 14-year-old female. The subject presented with gross hematuria. Medical imaging uncovered a left renal mass without regional or metastatic extension. The tumor showed morphological, immunohistochemical, and molecular features of DSRCT. Immunostaining revealed polyphenotypic differentiation. Molecular analysis detected the fusion transcript resulting from the t(11;22)(p13;q12) reciprocal translocation, which characterized this neoplasm. Desmoplastic small round cell tumor is a rare, aggressive neoplasm that mainly affects young males and that usually presents with widespread abdominal serosal involvement. This unusual localization should lead one to consider this tumor in the differential diagnosis of small blue round cell tumors of the kidney.
Real-time in vivo visualization of oxidative stress in duckweed (Lemna minor L.)
Authors: Razinger Jaka , Drinovec Luka , Zrimec Alexis
Published: July 2007

An experimental set-up which enabled non-invasive, real-time reactive oxygen species (ROS) visualization on a whole plant level was constructed. In the test organism, Lemna minor L. (common duckweed), apoplastic and symplastic oxidative stress was evaluated by exposure to menadione (50 μM), menadione (50 μM) + ascorbate (100 μM) or neither for control. Menadione (50 μM) caused a statistically significant increase in H2DCFDA fluorescence in the apoplast after 60 minutes of exposure. The addition of ascorbate (100 μM) in the test medium significantly decreased apoplastic oxidative stress. 50 μM menadione caused an increase in symplastic H2DCFDA fluorescence in 57% of fronds. The exposure of L. minor plants to both menadione and ascorbate decreased the rate of fluorescence intensity accumulation in the symplast to control levels. The method has proven to be quick and straightforward and could be applied to a range of chemicals in various physiological and toxicological plant studies. The advantages of the set-up and different possible artefacts are discussed.
Charge Transfer Excitons in Bulk Heterojunctions of a Polyfluorene Copolymer and a Fullerene Derivative
Authors: Loi M. A. , Toffanin S. , Muccini M. , Forster M. , Scherf U. , Scharber M.
Published: July 2007

The photophysical properties of blends of fluorene copolymer and the fullerene derivative PCBM are analyzed with a particular attention to photovoltaic applications. The properties of the blends are determined by the relative alignment of the HOMO energy levels. In the blend where the HOMO levels of the copolymer and the fullerene are aligned there is not signature of charge stabilization and photovoltaic effect. While in the blend where there is an offset between the HOMO levels the charge stabilization is accompanied by good photovoltaic performances. The photoluminescence spectrum of the latter blend is characterized by the appearance of a new peak at low energy with a lifetime of a few ns that red‐shifts with the increase of the PCBM percentage. The feature is attributed to the emission from a charge‐transfer exciton that is red‐shifted by the change of dielectric constant of the medium.
Dual‐Activity Controlled Asymmetric Synthesis of Superconducting Lead Hemispheres**
Authors: Lu X. L. , Wang W. , Zhang G. Q. , Li X. G.
Published: July 2007

A binary surfactant mixture of cetyltrimethylammonium bromide and polyvinyl pyrrolidone is used as the tailoring agent in the fabrication of lead micro/nanostructures. Electron microscopy studies indicate that the morphologies of the products can be efficiently controlled in this simple one‐step synthetic procedure. Intriguingly, well‐defined asymmetric functional colloids, Pb hemispheres, are obtained for the first time, and a dual‐activity‐controlled growth process is proposed to explain their formation. The magnetization measurements show that the as‐prepared samples are superconducting with the same transition temperature as bulk Pb. These findings prove the unique morphology tailoring efficacy of mixed surfactants, which could be used to obtain more variform structures or architectures in the fabrication of advanced materials.
Photoemission Electron Microscopy of TiO2 Anatase Films Embedded with Rutile Nanocrystals
Authors: Xiong G. , Shao R. , Droubay T. C. , Joly A. G. , Beck K. M. , Chambers S. A. , Hess W. P.
Published: July 2007

Photoemission electron microscopy (PEEM) excited by X‐ray and UV sources is used to investigate epitaxial anatase thin films with embedded rutile nanocrystals, a model system for the study of heterocatalysis on mixed‐phase TiO2. Both excitation sources show distinct contrast between the two TiO2 phases; however, the contrast is reversed. Rutile nanocrystals appear darker than the anatase film in X‐ray PEEM images but brighter in UV‐PEEM images. We observe that topography‐induced contrast is dominant in X‐ray PEEM imaging, whereas work function and density‐of‐state‐based contrast, dominates in UV‐PEEM. This assertion is confirmed by UPS and conducting AFM data that shows the rutile work function to be 0.2 eV lower and a greater occupied valence band density‐of‐states in rutile (100) than in anatase (001). Since the boundaries between rutile nanocrystals and the anatase film are clearly resolved, these results indicate that PEEM studies of excited state dynamics and heterocatalysis are possible at chemically intriguing mixed‐phase TiO2 interfaces and grain boundaries.
Effects of the vulcanizing reagent addition on the properties of CNTs/SBR powder composites
Authors: Zhou Xiangwen , Zhu Yuefeng , Liang Ji
Published: July 2007

Vulcanizing reagent (VR) suspensions with different sulfur additions were mixed with CNTs suspensions and SBR latex, and then powder CNTs/SBR (PSBR) composites were prepared by spray‐drying process. Investigations showed that VR additions have significant influences on the properties of CNTs/PSBR composites. With the increment of VR additions, glass transition temperature (Tg) of the composites increased gradually, and reached the maximum when the sulfur addition was 4.0 phr, and then it would decrease if the sulfur addition continued to rise. The elongation at break of the vulcanizates decreased linearly. The tensile strength and hardness reached the maximum when the sulfur addition was 4.0 phr, and almost kept constant when the addition continued to rise. Yet the tear strength reached the maximum when the addition was of 2.5 phr, and then decreased slightly when the addition exceeded 4.0 phr, which was corresponding to the structure designability of the composites affected by the sulfur aggregates in the matrix. Under different temperatures, when the vulcanizing temperature was 150°C, the vulcanizing speed was proper, vulcanizing time was prolonged, and the vulcanizing security was intensified. Compared with the vulcanization of carbon black/PSBR composites, more sulfur additions are needed in the vulcanization of CNTs/PSBR composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Effects of the injection‐molding temperatures and pyrolysis cycles on the butadiene phase of high‐impact polystyrene
Authors: Parres F. , Balart R. , Crespo J. E. , López J.
Published: July 2007

Recycling is a thermal process in which polymers are melted to produce new products. It is possible that these thermal processes could modify their mechanical and thermal properties. Polymer degradation can be characterized with thermogravimetric analysis and differential scanning calorimetry. Recycled materials tested with these methods have shown variations in some thermal properties, such as the glass‐transition temperature and thermal degradation onset, but the sensitivity of these methods is not sufficient to investigate the changes in the characteristics of polymers when materials are exposed to moderate temperature conditions or several thermal cycles. To study these structural changes, a much more sensitive technique, such as pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS), is needed. Small variations in the structure can be determined by Py–GC/MS. Each pyrolysis product can be identified by its retention time and mass spectrum with the use of reference literature. In this work, we have studied structural changes in high‐impact polystyrene as a function of the injection‐molding temperature and pyrolysis cycles. The results do not show significant changes in samples processed at different temperatures with Py–GC/MS, but the values of the pyrolysis products differ as a function of the pyrolysis cycles. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Preparation and characterization of konjac glucomannan/poly(diallydimethylammonium chloride) blend films
Authors: Lu Jun , Zhang Jinhua , Xiao Chaobo
Published: July 2007

A novel preservative film was prepared by blending konjac glucomannan (KGM) and poly (diallydimethylammonium chloride) (PDADMAC) in aqueous system. The effects of PDADMAC content on the miscibility, morphology, thermal stability, and mechanical properties of the blend films were investigated by density determination, scanning electron microscopy (SEM), attenuated total reflection infrared spectroscopy (ATR‐IR), X‐ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and tensile tests. The results of the density determination predicted that the blends of KGM and PDADMAC were miscible when the PDADMAC content was less than 70 wt %. Moreover, SEM and XRD confirmed the result. ATR‐IR showed that strong intermolecular hydrogen bonds interaction occurred between the negative charge groups of KGM and the quaternary ammonium groups of PDADMAC in the blends. The tensile strength and the break elongation of the blends were improved largely to 106.5 MPa and 32.04%, when the PDADMAC content was 20 wt %. The thermal stability of the blends was higher than pure KGM. Results from the film‐coating preservation experiments with lichi and grapes showed that the blend film had excellent water‐holding and preservative ability. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synthesis, characterization, and cure reaction of methacrylate‐based multifunctional monomers for dental composites
Authors: Ghaemy Mousa , Heidaripour Maryam , Barghamadi Mohamad
Published: July 2007

The synthesis of 2,2‐bis[(4‐(2‐hydroxy‐3‐methacryloxyethoxy)phenyl]propane (BHEP) and (1‐methacryloxy‐3‐ethoxymethacryloxy‐2‐hydroxy)propane (MEHP) for use as the monomer phase in dental composites are reported. The monomers were prepared by the reaction of 2‐hydroxyethyl methacrylate (HEMA) with diglycidyl‐ether of bisphenol A (DGEBA) and with glycidyl methacrylate (GMA), respectively. The progress of the reaction was followed by measuring the disappearance of the epoxide group peak using FTIR and the structure of the monomers was characterized by 1H‐NMR. BHEP and MEHP have lower viscosity because of the presence of long aliphatic spacer on both sides of the aromatic ring in BHEP and the absence of aromatic rings and the presence of only one hydroxyl group in each molecule of MEHP. Thermal curing of the monomers was conducted in a DSC using benzoyl peroxide as an initiator. Photopolymerization of the monomers was also conducted with the visible light using camphorquinone and N,N‐dimethylaminoethyl methacrylate as the photoinitiating system. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Reduction of the Volatile Matter Evolution Rate from a Plastic Pellet during Bubbling Fluidized Bed Pyrolysis by Using Porous Bed Material
Authors: Winaya I. N. S. , Shimizu T.
Published: July 2007

Rapid volatile matter evolution from high‐volatile fuels such as wastes and biomass is one of problems associated with fluidized bed incinerators and gasifiers. When volatile matter evolves rapidly in the vicinity of the fuel feed point, the mixing of volatile matter with reactant gas is poor, and therefore, unreacted volatile matter is expected to be released from the reactor. In the present work, reduction of the volatile matter evolution rate was attempted by employing porous solids as bed materials instead of nonporous sand. The effect of bed material on the onset of devolatilization was measured by use of a bench‐scale bubbling fluidized bed reactor. Volatile matter capture by the porous solids (capacitance effect) and the heat transfer rate within the bed, both of which affect volatile matter evolution rate, were also measured. Four types of porous solids, both with and without capacitance effect, were employed as the bed material. By employing porous solids without capacitance effect, the contributions of reduced heat transfer rate and capacitance effect to the delay of volatile matter evolution can be evaluated separately. For porous bed materials with a moderate capacitance effect (volatile matter capture of up to 20 %), the delay of the onset of devolatilization, which was measured by detecting the flame combustion of the volatile matter, was explained by the lower heat transfer between the fuel and bed. However, for a porous particle with high capacitance effect (volatile matter capture of 30 %), the capacitance effect also affected the delay of the onset of the flame combustion.
Investigation of the Effect of a Dividing Wall in a Moving Bed
Authors: Chen Y.‐H. , Zhu X.‐D. , Wu Y.‐Q. , Zhu Z.‐B.
Published: July 2007

Moving beds are widely used in many scientific fields due to their advantages, but their operation is affected by the phenomena of cavity and pinning, which should be avoided. In this article, a perforated dividing wall was located in a two‐dimensional rectangular moving bed with gas cross‐flow and the effect of the wall on some properties of the moving bed was investigated. Experimental results show that the location of the perforated dividing wall can improve the upper limit of the gas velocity of the moving bed since it prohibits the existence of a cavity and pinning. The dividing wall separates the apparatus into two channels. A cavity forms in the channel close to the upstream face while pinning occurs in the other channel. In comparison to a moving bed without a dividing wall, the cavity size and pinning width in a moving bed with a dividing wall are smaller at the same gas velocity.
Elucidation of Factors Affecting the Electronic Structures of Magnesium(II) and Zinc(II) Tetraarylporphyrin Radical Cations
Authors: Barzilay Claudia M. , Sibilia Sharon A. , Spiro Thomas G. , Gross Zeev
Published: July 2007

A series of magnesium and zinc tetraarylporphyrins and their porphyrinoxidized derivatives were studied by UV/Vis, ESR, and resonance Raman spectroscopy at various temperatures. The series included tetra(meta‐dichlorophenyl)porphyrinatozinc (5), tetra(ortho‐dichlorophenyl)porphyrinatozinc (6), tetra(ortho‐difluorophenyl)porphyrinatozinc and ‐magnesium (9 and 10), and tetra(pentafluorophenyl)porphyrinatozinc and ‐magnesium (7 and 8). The radical cations (3a‐10a) were isolated by chemical one‐electron oxidation of their neutral precursors (3‐10). Despite the structural similarity of all these radicals, their electronic ground state varied within the series. The position of the chloro groups was found to play a key role. While the radical cation of the meta‐dichloro‐substituted derivative 5a exhibited A2u spectroscopic features, the ortho‐dichlorophenyl derivative (6a) showed A1u spectral features. Radicals of the fluoro‐substituted porphyrins, especially that of 10, were found to have state‐admixed (A1u/A2u) electronic structures, and the relative contributions of the two states was found to vary with temperature and to depend on the axial ligand. The results indicate that the fluoro‐substituted porphyrins are primarily A2u at low temperature, even though their room temperature spectroscopic features resemble those of A1u cations. The elucidation of factors that affect the electronic structures of the radicals in the present series is helpful in providing a greater understanding of the spin‐spin interactions in the intermediates of heme‐dependant enzymatic reactions and their synthetic analogues.
Synthesis, Reactions, and Molecular Structures of Ethylzinc Enolates of Chiral N‐Substituted β‐Carbonyl Sulfoximines
Authors: Bolm Carsten , Müller Jürgen , Zehnder Margareta , Neuburger Markus A.
Published: July 2007

The preparation, structural characterization, and reactivity of ethylzinc‐containing enolates and organometallics derived from β‐carbonyl sulfoximines are reported. X‐ray crystal structures show significant differences between aggregated species obtained from β‐keto and β‐amido sulfoximines. Whereas the former gives an O‐metalated ethylzinc enolate, the latter crystallizes as C‐metalated carbonyl species. NMR investigations reveal the presence of chelated zinc enolates in solution. The relationship between structure and reactivity is demonstrated by the reaction profiles of the ethylzinc‐containing compounds. A high diastereoselectivity (> 90% de) was observed in the aldol reaction between the metalated β‐amido sulfoximine and benzaldehyde in the presence of trimethylsilyl chloride.
ortho‐Chelating Arenethiolatocopper(I) Complexes as Versatile Catalysts in the Regioselective Cross‐Coupling of Allylic Derivatives with nBuMgI—An Example of Reversed Reactivity of Leaving Groups
Authors: Persson Eva S. M. , van Klaveren Mayra , Grove David M. , Bäckvall Jan E. , van Koten Gerard
Published: July 2007

The regioselectivity in the arenethiolatocopper(I)‐catalyzed crosscoupling reaction of allylic substrates was studied. It was found that allylic acetates gave highly γ‐selective reactions in Et2O at 0°C with slow addition of the Grignard reagent, whereas α‐selective reactions were obtained in THF at −30°C with fast addition of the Grignard reagent. It is proposed that the formation of an intermediate in Et2O, in which the allylic acetate coordinates in a bidentate fashion the arenethiolatocopper(I) catalyst, dramatically increases the reactivity of the leaving group and results in excellent γ‐selectivity. The remarkable observation that an allylic acetate can be made more reactive than an allylic chloride by using the arenethiolatocopper(I) catalyst 1a supports the theory of a bidentate coordination of the substrate to the catalyst through its double bond and acetate oxygen.
The Stereochemistry of Carbenoid Cyclopropanation Reactions
Authors: Stiasny Hans Christian , Hoffmann Reinhard W.
Published: July 2007

The stereochemical course of the intramolecular carbenoid cyclopropanation reaction has been studied for the epimeric carbenoids 12a and 12b. In these reactions the tert‐butyldimethylsilyloxy substituent serves as an internal stereochemical reference point. It was found that 12b cyclizes rapidly at −110°C in a complexation‐assisted concerted process to give the bicyclo[3.1.0]hexane 16. The diastereomer 12a cyclizes more slowly at −100°C to give both 16 and 17; the former is probably formed by a complexation‐assisted carbolithiation pathway.
What Do Ab Initio Calculations Predict for the Structure of Lithiated Azaenolates of Peptides?
Authors: Feigel Martin , Martinek Gisela , Sauer Wolfgang H. B.
Published: July 2007

Structures and conformations of the azaenolate lithium salts of amides (formamide, acetamide, and N‐methylacetamide) and of the dipeptide model N‐formylalaninamide were investigated by means of ab initio MO theory. Four possible structures of the lithiated C‐enolates of acetamide were also included in the study. All structures were calculated at the HF/6‐31+G(d) and MP2(fc)/6‐31 + G(d)/HF/6‐31 + G(d) levels; the lithiated azaenolates of formamide were also investigated at higher theoretical levels (up to MP4(fc)/6‐311 + G(d,p)/MP2(fc)/6‐311 + G(d,p)). For the lithiated azaenolates of all amides investigated, the most stable structure contains a four‐membered ring in which the lithium ion is complexed by the oxygen and nitrogen atoms; the substituents attached to the carbon and nitrogen atoms of the azaenolate are in a cis arrangement. The lithiated azaenolates of acetamide are predicted to be more stable than the corresponding C‐enolates. To simulate solvation, calculations on complexes of the lithiated azaenolates of formamide with up to three molecules dimethyl ether were also performed, and all azaenolates of amides were also reoptimized by ab initio reaction‐field calculations. Both solvation models reduce the preference for lithium‐chelated cis structures. The Ramachandran maps of the dilithiated bis(azaenolate) of N‐formylalaninamide (having cis or trans arrangements of the azaenolate substituents) were scanned by MNDO calculations for conformational accessible regions. Thirteen stable structures were subsequently optimized at the HF/6‐31 + G(d) ab initio level. The global minimum resembles a peptide in C7 conformation, but other conformations, not known for peptides, are close in energy. The structures of dimers of the lithiated azaenolates of N‐methylacetamide and of glycinaldehyde were also calculated. The NMR chemical shielding of carbon, nitrogen, and oxygen atoms in all structures were predicted ab initio by using the gauge‐including atomic orbital (GIAO) method.
The “Peroxo Perrhenic Acid” H4Re2O13: An Oxygen‐Rich Metal Peroxide and Oxidation Catalyst
Authors: Herrmann Wolfgang A. , Correia João D. G. , Kühn Fritz E. , Artus Georg R. J. , Romã Carlos C.
Published: July 2007

The rhenium oxides Re2O7 and ReO3 react with hydrogen peroxide solutions yielding peroxo complexes that efficiently catalyze the oxidation of olefins, aromatics, and certain organometallic compounds. In contrast, related oxides of molybdenum (MoO3) and vanadium (V2O5) do not activate H2O2 under comparable conditions. The active rhenium peroxo complex was isolated from the system Re2O7/H2O2: the crystalline red‐orange, explosive compound of formula H4Re2O13 is the most oxygen rich rhenium compound isolated to date. Its structure resembles a “peroxo perrhenic acid”. The binuclear compound could be isolated in the form of a diglyme adduct, structurally defined as two corner‐sharing pentagonal bipyramids with apical oxo and aquo ligands; the equatorial positions are occupied by the bridging oxygen and by n2‐peroxo groups (two [O2]2− ligands per rhenium). In contrast to the known complex [CH3ReO(O2)2].H2O, the new peroxo species [O{ReO(O2)2.H2O}2] decomposes hydrolytically during the catalytic cycle and can thus not compete in terms of catalytic activity in oxidation reactions involving H2O2. Hydrolysis yields “perrhenic acid” Re2O7.2H2O, the diglyme adduct of which compound was also characterized by means of an X‐ray diffraction analysis.
The Effect of Microsolvation on E2 and SN2 Reactions: Theoretical Study of the Model System F− + C2H5F + nHF
Authors: Matthias Bickelhaupt F. , Baerends Evert Jan , Anibbering Nico M. M.
Published: July 2007

The model reaction system F− +C2H5F + nHF (n = 0–4) has been investigated by use of a density‐functional method, in order to achieve a qualitative understanding of the effect of solvation on the E2 and SN2 reactions. Two characteristic effects already occur upon monosolvation: a) the activation energies of the E2 and SN2 pathways increase significantly and even become positive, because reactants are more strongly solvated than transition states; b) the SN2 transition state is stabilized much more and becomes lower in energy than the anti‐E2 transition state. This agrees with general experience from gas‐ and condensed‐phase experiments. The solvation is analyzed from two complementary viewpoints: a) as an interaction between solvent molecules and the F−/C2H5F reaction system; b) as an interaction between the [F−, nHF] solvated base and the C2H5F substrate. The extent to which condensed‐phase characteristics can be modeled by this microsolvation approach is discussed.
A Novel Route to Racemic and Nonracemic Products of the Ugi Reaction: Synthesis of Ugi′s Labile α‐Adducts from Iminoaziridines and Carboxylic Acids, and their Transformations
Authors: Quast Helmut , Aldenkortt Sven
Published: July 2007

Iminoaziridines (11) are highly reactive synthetic equivalents for three of the four components in the Ugi four‐component condensation. Thus, iminoaziridines react rapidly with carboxylic acids at temperatures as low as –20°C to afford α‐amino isoimides (14), which are identical to the elusive α‐adducts of isocyanides in the Ugi reaction. 1,4‐Migration of the acyl group (O → α‐N) in 14 furnishes the α‐acylamino amides 15. Very little, if any, racemisation is observed when carboxylic acids react with nonracemic iminoaziridines [(R)‐11 a,c], which are readily available. Mumm rearrangement by O → N‐acyl 1,3‐migration to afford α‐amino imides (16 e, f) competes if the O → α‐N 1,4‐shift is slowed down by steric hindrance. The latter acyl shift is catalysed by carboxylic acids while the former is not. The iminoaziridines (R)‐11 a,c react quantitatively and without racemisation with hydrazoic acid to produce the 5‐aminoalkyltetrazoles (R)‐21 a,c.
Nucleophilic Addition of Secondary Phosphines to Cationic Dienyl Tricarbonyliron Complexes: A novel Route to Optically Active Phosphines
Authors: Englert Ulli , Ganter Beate , Käser Markus , Klinkhammer Elke , Wagner Trixie , Salzer Albrecht
Published: July 2007

Secondary phosphines such as HPPh2 and to the cationic iron dienyl complex [η5‐(1R)‐ethylnopadienyl)Fe‐(CO)3]+ (1) by nucleophilic addition. The phosphonium salt initially formed is readily deprotonated to yield an optically active tertiary phosphine [(n4‐(1 R)‐ethylnopadienePPh2)Fe(CO)3] (2b). A similar reaction also occurs with [C6H7Fe‐(CO)3]+ (3) and [C7H9Fe(CO)3]+ (4) to give [(C6H7PPh2)Fe(CO)3] (5) and [(C7H9PPh2)Fe(CO)3] (6) in good yields. The mechanism of formation of these novel phosphines is discussed. Complex 2 b crystallizes in the space group P212121 (no. 19); 5 crystallizes in the space group P21/c (no. 14). Like other monodentate optically active phosphines, 2 b is capable of coordinating to transition metal complexes. It forms palladium complexes on reaction with [{μ‐chloro(allyl)palladium}2] as well as with [{μ‐chloro[(N,N‐dimethylamino‐kN‐2‐methyl)phenyl‐kC]palladium}2] (11). The latter reaction product crystallizes in the space group P31 (no. 144).