bluuebunny/crossref_metadata_2025 huggingface dataset:
Protective role of 1α, 25‐dihydroxyvitamin D3 against oxidative stress in nonmalignant human prostate epithelial cells
Authors: Bao Bo‐Ying , Ting Huei‐Ju , Hsu Jong‐Wei , Lee Yi‐Fen
Published: March 2008

Overproduction of reactive oxygen species (ROS), through either endogenous or exogenous sources, could induce DNA damage, and accumulation of DNA damage might lead to multistep carcinogenesis. The antioxidative effects of vitamin D have been suggested by epidemiological and many in vitro and in vivo laboratory studies. While exploring the antioxidative effects of vitamin D in prostate cells, we found that the active form of vitamin D, 1α, 25‐dihydroxyvitamin D3 (1,25‐VD), can protect nonmalignant human prostate epithelial cell lines, BPH‐1 and RWPE‐1, but not malignant human prostate epithelial cells, CWR22R and DU 145, from oxidative stress‐induced cell death. Glucose‐6‐phosphate dehydrogenase (G6PD), a key antioxidant enzyme, was dose‐ and time‐dependently induced by 1,25‐VD. Mechanistic studies using chromatin immunoprecipitation (ChIP) assay revealed that a direct repeat‐3 (DR3) vitamin D response element located in the first intron of the G6PD genome can be bound by liganded vitamin D receptor, thereby regulating G6PD gene expression. Increasing G6PD activity and glutathione level by 1,25‐VD can scavenge cellular ROS. Moreover, the protective effects of 1,25‐VD were abolished by dehydroepiandrosterone, a noncompetitive inhibitor of G6PD activity. Together, our results showed that 1,25‐VD can protect nonmalignant prostate cells from oxidative stress‐induced cell death by elimination of ROS‐induced cellular injuries through transcriptional activation of G6PD activity. The antioxidative effect of vitamin D strengthens its roles in cancer chemoprevention and adds to a growing list of beneficial effects of vitamin D against cancer. © 2008 Wiley‐Liss, Inc.
Expression and localization of estrogen receptor α in the C2C12 murine skeletal muscle cell line
Authors: Milanesi Lorena , de Boland Ana Russo , Boland Ricardo
Published: March 2008

The classical model of 17β‐estradiol action has been traditionally described to be mediated by the estrogen receptor (ER) localized exclusively in the nucleus. However, there is increasing functional evidence for extra nuclear localization of ER. We present biochemical, immunological and molecular data supporting mitochondrial‐microsomal localization of ERα in the C2C12 skeletal muscle cell line. We first established [3H]17βestradiol binding characteristics in whole cells in culture. Specific and saturable [3H]17βestradiol binding sites of high affinity were then detected in mitochondrial fractions (Kd = 0.43 nM; Bmax = 572 fmol/mg protein). Immunocytological studies revealed that estrogen receptors mainly localize at the mitochondrial and perinuclear level. These results were also confirmed using fluorescent 17βestradiol‐BSA conjugates. The immunoreactivity did not translocate into the nucleus by 17β‐estradiol treatment. Western and Ligand blot approaches corroborated the non‐classical localization. Expression and subcellular distribution of ERα proteins were confirmed in C2C12 cells transfected with ERα siRNA and by RT‐PCR employing specific primers. The non‐classical distribution of native pools of ERα in skeletal muscle cells suggests an alternative mode of ER localization/function. J. Cell. Biochem. 104: 1254–1273, 2008. © 2008 Wiley‐Liss, Inc.
Non‐enzymatic glycation of type I collagen diminishes collagen–proteoglycan binding and weakens cell adhesion
Authors: Reigle Kristin L. , Di Lullo Gloria , Turner Kevin R. , Last Jerold A. , Chervoneva Inna , Birk David E. , Funderburgh James L. , Elrod Elizabeth , Germann Markus W. , Surber Charles , Sanderson Ralph D. , San Antonio James D.
Published: March 2008

Non‐enzymatic glycation of type I collagen occurs in aging and diabetes, and may affect collagen solubility, charge, polymerization, and intermolecular interactions. Proteoglycans1 (PGs) bind type I collagen and are proposed to regulate fibril assembly, function, and cell–collagen interactions. Moreover, on the collagen fibril a keratan sulfate (KS) PG binding region overlaps with preferred collagen glycation sites. Thus, we examined the effect of collagen modified by simple glycation on PG–collagen interactions. By affinity coelectrophoresis (ACE), we found reduced affinities of heparin and KSPGs for glycated but not normal collagen, whereas the dermatan sulfate (DS)PGs decorin and biglycan bound similarly to both, and that the affinity of heparin for normal collagen decreased with increasing pH. Circular dichroism (CD) spectroscopy revealed normal and glycated collagens to assume triple helical conformations, but heparin addition caused precipitation and decreased triple helical content—effects that were more marked with glycated collagen. A spectrophotometric assay revealed slower polymerization of glycated collagen. However, ultrastructural analyses indicated that fibrils assembled from normal and glycated collagen exhibited normal periodicity, and had similar structures and comparable diameter distributions. B‐cells expressing the cell surface heparan sulfate PG syndecan‐1 adhered well to normal but not glycated collagen, and endothelial cell migration was delayed on glycated collagen. We speculate that glycation diminishes the electrostatic interactions between type I collagen and PGs, and may interfere with core protein‐collagen associations for KSPGs but not DSPGs. Therefore in vivo, collagen glycation may weaken PG–collagen interactions, thereby disrupting matrix integrity and cell–collagen interactions, adhesion, and migration. J. Cell. Biochem. 104: 1684–1698, 2008. © 2008 Wiley‐Liss, Inc.
CBF/NF‐Y controls endoplasmic reticulum stress induced transcription through recruitment of both ATF6(N) and TBP
Authors: Luo Rong , Lu Jing‐Fang , Hu Qianghua , Maity Sankar N.
Published: March 2008

Previously the analysis of promoters regulated by endoplasmic reticulum (ER) stress identified a composite promoter element, ERSE that interacts with both CBF/NF‐Y (CBF) and ATF6(N) transcription factors. This prompted us to investigate the underlying mechanism by which CBF, a ubiquitously binding transcription factor, specifically controls transcription activation during ER stress. The in vitro DNA binding study performed using purified recombinant proteins revealed that CBF specifically recruits ATF6(N) to ERSE DNA but it does not interact with ATF6(N) in absence of DNA binding. Inhibition of CBF binding resulted in a significant reduction of optimal transcription activation of cellular genes during ER stress. Analysis of cellular promoters by ChIP demonstrated that CBF is needed for recruitment of both ATF6(N) and TBP but not for either acetylation of histone H3‐K9 or trimethylation of histone H3‐K4 during ER stress. Together these study results reveal that CBF controls ER stress‐inducible transcription through recruitment of both ATF6(N) and TBP but not through chromatin modifications. Our observations are in agreement with the results of recently published studies that have shown that CBF controls transcription of varieties of inducible promoters through recruitment of general transcription factors but not through acetylation of histone H4. These findings provide a paradigm of the function of CBF in inducible transcription. J. Cell. Biochem. 104: 1708–1723, 2008. © 2008 Wiley‐Liss, Inc.
Differential regulation of mTOR‐dependent S6 phosphorylation by muscarinic acetylcholine receptor subtypes
Authors: Slack Barbara E. , Blusztajn Jan K.
Published: March 2008

Muscarinic receptors subserve many functions in both peripheral and central nervous systems. Some of these processes depend on increases in protein synthesis, which may be achieved by activation of mammalian target of rapamycin (mTOR), a kinase that regulates protein translation capacity. Here, we examined the regulation of mTOR‐dependent signaling pathways by muscarinic receptors in SK‐N‐SH human neuroblastoma cells, and in human embryonic kidney (HEK) cell lines transfected with individual muscarinic receptor subtypes. In SK‐N‐SH cells, the acetylcholine analog carbachol stimulated phosphorylation of the ribosomal S6 protein, a downstream target of mTOR. The sensitivity of the response to subtype‐selective muscarinic receptor antagonists indicated that it was mediated by M3 receptors. Carbachol‐evoked S6 phosphorylation was blocked by the mTOR inhibitor rapamycin, but was independent of phosphoinositide 3‐kinase activation. The response was significantly reduced by the mitogen‐activated protein kinase kinase (MEK) inhibitor U0126, which also inhibited carbachol‐evoked S6 phosphorylation in HEK cells expressing M2 receptors, but was ineffective in M3 receptor‐expressing HEK cells, although carbachol activated MAPK in both transfected lines. The p90 ribosomal S6 kinase has been implicated in mTOR regulation by phorbol esters, but was not activated by carbachol in any of the cell lines tested. The protein kinase C inhibitor bisindolylmaleimide I reduced carbachol‐stimulated S6 phosphorylation in SK‐N‐SH cells, and in HEK cells expressing M3 receptors, but not in HEK cells expressing M2 receptors. The results demonstrate that multiple muscarinic receptor subtypes regulate mTOR, and that both MAPK‐dependent and ‐independent mechanisms may mediate the response in a cell context‐specific manner. J. Cell. Biochem. 104: 1818–1831, 2008. © 2008 Wiley‐Liss, Inc.
PEDF from mouse mesenchymal stem cell secretome attracts fibroblasts
Authors: Sarojini Harshini , Estrada Rosendo , Lu Hongwei , Dekova Silvia , Lee Menq‐Jer , Gray Robert D. , Wang Eugenia
Published: March 2008

Conditioned medium (secretome) derived from an enriched stem cell culture stimulates chemotaxis of human fibroblasts. These cells are classified as multipotent murine mesenchymal stromal cells (mMSC) by immunochemical analysis of marker proteins. Proteomic analysis of mMSC secretome identifies nineteen secreted proteins, including extracellular matrix structural proteins, collagen processing enzymes, pigment epithelium‐derived factor (PEDF) and cystatin C. Immunodepletion and reconstitution experiments show that PEDF is the predominant fibroblast chemoattractant in the conditioned medium, and immunofluorescence microscopy shows strong staining for PEDF in the cytoplasm, at the cell surface, and in intercellular space between mMSCs. This stimulatory effect of PEDF on fibroblast chemotaxis is in contrast to the PEDF‐mediated inhibition of endothelial cell migration, reported previously. These differential functional effects of PEDF toward fibroblasts and endothelial cells may serve to program an ordered temporal sequence of scaffold building followed by angiogenesis during wound healing. J. Cell. Biochem. 104: 1793–1802, 2008. © 2008 Wiley‐Liss, Inc.
DNA damage, RAD9 and fertility/infertility of Echinococcus granulosus hydatid cysts
Authors: Cabrera Gonzalo , Cabrejos María Eugenia , Morassutti Alessandra Loureiro , Cabezón Carolina , Orellana Juana , Hellman Ulf , Zaha Arnaldo , Galanti Norbel
Published: March 2008

Hydatidosis, caused by the larval stage of the platyhelminth parasite Echinococcus granulosus, affects human and animal health. Hydatid fertile cysts are formed in intermediate hosts (human and herbivores) producing protoscoleces, the infective form to canines, at their germinal layers. Infertile cysts are also formed, but they are unable to produce protoscoleces. The molecular mechanisms involved in hydatid cysts fertility/infertility are unknown. Nevertheless, previous work from our laboratory has suggested that apoptosis is involved in hydatid cyst infertility and death. On the other hand, fertile hydatid cysts can resist oxidative damage due to reactive oxygen and nitrogen species. On these foundations, we have postulated that when oxidative damage of DNA in the germinal layers exceeds the capability of DNA repair mechanisms, apoptosis is triggered and hydatid cysts infertility occurs. We describe a much higher percentage of nuclei with oxidative DNA damage in dead protoscoleces and in the germinal layer of infertile cysts than in fertile cysts, suggesting that DNA repair mechanisms are active in fertile cysts. rad9, a conserved gene, plays a key role in cell cycle checkpoint modulation and DNA repair. We found that RAD9 of E. granulosus (EgRAD9) is expressed at the mRNA and protein levels. As it was found in other eukaryotes, EgRAD9 is hyperphosphorylated in response to DNA damage. Our results suggest that molecules involved in DNA repair in the germinal layer of fertile hydatid cysts and in protoscoleces, such as EgRAD9, may allow preserving the fertility of hydatid cysts in the presence of ROS and RNS. J. Cell. Physiol. 216: 498–506, 2008. © 2008 Wiley‐Liss, Inc.
Adenovirus E1A oncoprotein liberates c‐Myc activity to promote cell proliferation through abating Bin1 expression via an Rb/E2F1‐dependent mechanism
Authors: Kinney Erica L. , Tanida Satoshi , Rodrigue Amelie A. , Johnson Joanna K. , Tompkins Van S. , Sakamuro Daitoku
Published: March 2008

Adenovirus E1A oncogene transforms primary rodent fibroblasts in cooperation with activated Ras. Conversely, the c‐Myc oncoprotein‐binding tumor suppressor, Bin1, inhibits Ras/E1A‐mediated cell transformation. Since E1A does not directly bind to and inhibit Bin1, the primary mechanism by which E1A counteracts Bin1 to liberate oncogenic c‐Myc activity is poorly understood. Here we show that wild‐type E1A, but not an Rb binding‐defective E1A mutant, suppresses endogenous Bin1 expression in cultured rodent fibroblasts. Similarly, other anti‐Rb agents, such as human papillomavirus E7, mitogenic stimuli, and small interfering RNA (siRNA) for Rb, consistently decrease Bin1 promoter activity. In contrast, serum starvation, which activates Rb, enhances endogenous Bin1 levels. These findings suggest that Bin1 may be a novel component of Rb‐mediated G1 arrest. Consistent with this premise, chromatin immunoprecipitation assays demonstrate that Rb protein directly interacts with the Bin1 promoter only upon removal of serum. Furthermore, ectopically expressed E2F1, which is primarily inhibited by Rb under serum‐starved condition, represses Bin1 promoter activity in a manner that is dependent on the DNA‐binding and transactivation domains of E2F1. Lastly, depletion of endogenous Bin1 per se is biologically meaningful since antisense or siRNA of Bin1 transfection releases endogenous c‐Myc transcriptional activity and, concomitantly, accelerates cell proliferation. Our results suggest that Bin1 gene suppression caused by oncogenic E1A via Rb inactivation is an essential step in cell cycle progression promoted by c‐Myc, and subsequently, E1A transformation. We propose a novel G1 arrest signaling mechanism by which Rb indirectly curbs oncogenic c‐Myc activity via sustaining Bin1 expression. J. Cell. Physiol. 216: 621–631, 2008, © 2008 Wiley‐Liss, Inc.
Synthesis and Raman spectroscopic characterisation of the oxalate mineral wheatleyite Na2Cu2+(C2O4)2·2H2O
Authors: Frost Ray L. , Locke Ashley , Martens Wayde N.
Published: March 2008

The mineral wheatleyite has been synthesised and characterised by Raman spectroscopy complimented with infrared spectroscopy. Two Raman bands at 1434 and 1470 cm−1 are assigned to the ν(CO) stretching mode and implies two independent oxalate anions. Two intense Raman bands observed at 904 and 860 cm−1 are assigned to the ν(CC) stretching mode and support the concept of two non‐equivalent oxalate units in the wheatleyite structure. Two strong bands observed at 565 and 585 cm−1 are assigned to the symmetric CCO in plane bending modes. The Raman band at 387 cm−1 is attributed to the CuO stretching vibration and the bands at 127 and 173 cm−1 to OCuO bending vibrations. A comparison is made with Raman spectra of selected natural oxalate bearing minerals. Oxalates are markers or indicators of environmental events. Oxalates are readily determined by Raman spectroscopy. Thus, deterioration of works of art, biogeochemical cycles, plant metal complexation, the presence of pigments and minerals formed in caves can be analysed. Copyright © 2008 John Wiley & Sons, Ltd.
A new limb salvage surgery in cases of high‐grade soft tissue sarcoma using photodynamic surgery, followed by photo‐ and radiodynamic therapy with acridine orange
Authors: Nakamura Tomoki , Kusuzaki Katsuyuki , Matsubara Takao , Matsumine Akihiko , Murata Hiroaki , Uchida Atsumasa
Published: March 2008

Background

To maintain excellent limb function after tumor resection in patients with high‐grade malignant sarcomas, we developed and established a new surgical adjuvant therapy using acridine orange (AO) after intra‐lesional or marginal resection while sparing normal tissues of major nerves, vessels or bones adjacent to the tumor.

Method

Our AO therapy procedure was combined with photodynamic surgery (PDS), photodynamic therapy (PDT) and radiodynamic therapy (RDT). In this study, 26 patients with primary high‐grade soft tissue sarcomas were treated with AO therapy.

Result

Results showed a low local recurrence rate (7.7%) and good local recurrence‐free rate (88%) after AO therapy. Limb function of all patients was maintained at 100% of ISOLS criteria.

Conclusion

Based on these results, we concluded that AO therapy is useful for local control after margin‐positive tumor resection and for preserving excellent limb function in patients with high‐grade soft tissue sarcomas. J. Surg. Oncol. 2008;97:523–528. © 2008 Wiley‐Liss, Inc.
Identification of protein‐coding and intronic noncoding RNAs down‐regulated in clear cell renal carcinoma
Authors: Brito Glauber Costa , Fachel Ângela A. , Vettore Andre Luiz , Vignal Giselle M , Gimba Etel R.P. , Campos Franz S. , Barcinski Marcello A. , Verjovski‐Almeida Sergio , Reis Eduardo M.
Published: March 2008

The clear cell subtype of renal cell carcinoma (RCC) is the most lethal and prevalent cancer of the urinary system. To investigate the molecular changes associated with malignant transformation in clear cell RCC, the gene expression profiles of matched samples of tumor and adjacent non‐neoplastic tissue were obtained from six patients. A custom‐built cDNA microarray platform was used, comprising 2292 probes that map to exons of genes and 822 probes for noncoding RNAs mapping to intronic regions. Intronic transcription was detected in all normal and neoplastic renal tissues. A subset of 55 transcripts was significantly down‐regulated in clear cell RCC relative to the matched nontumor tissue as determined by a combination of two statistical tests and leave‐one‐out patient cross‐validation. Among the down‐regulated transcripts, 49 mapped to untranslated or coding exons and 6 were intronic relative to known exons of protein‐coding genes. Lower levels of expression of SIN3B, TRIP3, SYNJ2BP and NDE1 (P < 0.02), and of intronic transcripts derived from SND1 and ACTN4 loci (P < 0.05), were confirmed in clear cell RCC by Real‐time RT‐PCR. A subset of 25 transcripts was deregulated in additional six nonclear cell RCC samples, pointing to common transcriptional alterations in RCC irrespective of the histological subtype or differentiation state of the tumor. Our results indicate a novel set of tumor suppressor gene candidates, including noncoding intronic RNAs, which may play a significant role in malignant transformations of normal renal cells. © 2008 Wiley‐Liss, Inc.
Distributive smoothers in multigrid for problems with dominating grad–div operators
Authors: Gaspar F. J. , Gracia J. L. , Lisbona F. J. , Oosterlee C. W.
Published: March 2008

In this paper, we present efficient multigrid methods for systems of partial differential equations that are governed by a dominating grad–div operator. In particular, we show that distributive smoothing methods give multigrid convergence factors that are independent of problem parameters and of the mesh sizes in space and time. The applications range from model problems to secondary consolidation Biot's model. We focus on the smoothing issue and mainly solve academic problems on Cartesian‐staggered grids. Copyright © 2008 John Wiley & Sons, Ltd.
Epoxy resin/plasticized carbon black composites. Part I. Electrical and thermal properties and their applications
Authors: Abdel‐Aal N. , El‐Tantawy Farid , Al‐Hajry A. , Bououdina M.
Published: March 2008

The development of conductive polymer composites remains an important endeavor in light of growing energy concerns. A conducting polymer composite in the presence of plasticized carbon black (CB) and epoxy resin has been developed. Room temperature electrical conductivity, mobility carriers (μ), and number of charges (N) increase by increasing CB content. Electrical conductivity–temperature dependence of the composite was investigated and negative temperature coefficient of conductivity (NTC) behavior of the composites was revealed. The mechanism of the NTC effect in materials is related to the thermal expansion of the epoxy matrix and barriers height energy. The current–voltage behavior of epoxy/CB composites shows a switching effect and the mechanism of negative resistance is interpreted in details. Thermal conductivity (γ) increases with increasing filler content and the experimental data was compared with a theoretical model based on energy balance equation. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Mechanical properties of wood plastic composite panels made from waste fiberboard and particleboard
Authors: Chaharmahali Majid , Tajvidi Mehdi , Najafi Saeed Kazemi
Published: March 2008

The possibility of producing wood‐plastic panels using a melt blend/hot press method was studied in this research. The studied panels were compared with conventional medium density fiberboard (MDF) and particleboard (PB) panels. Wood‐plastic panels were made from high density polyethylene (as resin) and MDF waste and PB waste (as natural fiber) at 60, 70, and 80% by weight fiber loadings. Nominal density and dimensions of the panels were 1 g/cm3 and 35 × 35 × 1 cm3, respectively. Mechanical properties of the panels including flexural modulus, flexural strength, screw and nail withdrawal resistances, and impact strength were studied. Results indicated that the mechanical properties of the composites were strongly affected by the proportion of the wood flour and polymer. Maximum values of flexural modulus of wood plastic panels were reached at 70% fiber content. Flexural strength, screw and nail withdrawal resistance, and impact strength of wood plastic composites declined with the increase in fiber content from 60 to 80%. This was attributed to the lack of compatibility between the phases. The produced panels outperformed conventional PB panels regarding their mechanical properties, which were acceptable when compared with MDF panels as well. The best feature in the produced panels was their screw withdrawal resistance, which is extremely important for screw joints in cabinet making. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Synthesis and characterizations of poly(α‐naphthylamine)—Nanocomposites
Authors: Anbarasan R. , Anandhakrishnan R. , Vivek G.
Published: March 2008

Poly(α‐naphthylamine) (PNA)—natural clay nanocomposites were prepared by in situ polymerization method through oxidative initiation method. Effect of nanoclay on the rate of polymerization (Rp) of Naphthylamine (NA), thermal stability of PNA, and conductivity of PNA were tested. Effect of nanoclay on the morphology of PNA was also tested. The TGA results inferred that the % weight residue remain above 700°C was increased with the increase of amount of clay. XRD results confirmed the intercalation of PNA into the basal spacing of natural clay. TEM showed the presence of nanosized particle in the PNA‐natural clay nanocomposites. The conductivity value of polymer‐nanocomposite has increased with the increase of amount of natural clay. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Effect of fiber‐mat anisotropy on 1D mold filling in LCM: A numerical investigation
Authors: Tan Hua , Pillai Krishna M.
Published: March 2008

The 1D flow experiment is one of the most common methods to measure the saturated and unsaturated permeabilities as well as to study the unsaturated flow in liquid composite molding (LCM) processes used for manufacturing polymer composites. The effective permeability along a flow direction in an anisotropic fiber mat, which is a function of the principal components of the permeability tensor and the angle between the principal and flow directions, is based on the assumption of uniform 1D flow in the mat. In the present paper, the validity of such unidirectional flow assumption is shown to depend on three factors, i.e., the fiber‐mat aspect ratio, the anisotropy ratio (the ratio of the major and minor principal in‐plane permeabilities), and the angle of the principal permeability direction. A mold‐filling simulation for hard‐mold LCM processes based on the control volume/finite element formulation is used to investigate how these three factors affect the 1D flow. A new algorithm for applying the uniform inlet‐pressure condition prevalent in the 1D flow mold under the constant‐flow‐rate injection is developed to match the actual conditions in the mold. Our numerical results show that the three aforementioned factors have significant influence on the inlet‐pressure history as well as on the mold‐filling pattern. Maximum deviations from the unidirectional flow predictions in the inlet‐pressure history as well as the flow‐front progress is seen when the principal permeability direction is at an angle of 45° with respect to the flow direction; these deviations worsen with a decrease in the mat aspect ratio and with an increase in the anisotropy ratio. However, the inlet‐pressure history remains linear and the progress of the average flow‐front remains predictable by the 1D flow theory. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
The effect of gamma and electron beam irradiation on the thermal and mechanical properties of injection‐moulded high crystallinity poly(propylene)
Authors: Hassan Medhat M. , El‐kelesh Nabil A. , Dessouki Ahmed M.
Published: March 2008

In the present study, the effect of gamma and electron beam (EB) irradiation on the thermal and mechanical properties of high crystalline polypropylene (HPP) was studied. To study the structural modifications of HPP polymer which could occur following these treatments at different doses (20, 40, 60, 80, 100, and 120 kGy) were applied to all samples. Nonirradiated HPP were used as control samples, differential scanning calorimetry analysis, thermogravimetric analysis, and Mechanical tests were carried out to evaluate the effect of both irradiation treatments (EB and gamma irradiation) on HPP samples. Irradiated samples of HPP decreases melting temperature (Tm) of matrix in EB more than in gamma rays up to 5°C. The changes of mechanical properties exhibit different radiation stability towards 60Co‐gamma radiation and EB radiation. This difference reflects much higher penetration of the gamma radiation through the polymeric material as a function of sample thickness. The degradation on polymer properties caused by gamma irradiation was more than that caused by EB irradiation. Next, we compared the effects of gamma and EB irradiation to determine which of these two processes better maintained the integrity of the irradiated product. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers.
Boehmite nanorod‐reinforced‐polyethylenes and ethylene/1‐octene thermoplastic elastomer nanocomposites prepared by in situ olefin polymerization and melt compounding
Authors: Halbach Tobias S. , Thomann Yi , Mülhaupt Rolf
Published: March 2008

Nanocomposites of polyethylene (HDPE) and poly(ethylene‐co‐1‐octene) thermoplastic elastomers, both containing boehmites with variable sizes, shapes, and aspect ratios (1–20), were prepared by means of in situ olefin polymerization and melt compounding. The in situ olefin polymerization in the presence of boehmite nanorods afforded nanocomposites containing 4–8 wt % of boehmite. In an alternative process, the in situ olefin polymerization was used to produce polyolefins with high boehmite content of 50 wt % as masterbatches for polyolefin melt compounding with ethylene homo‐ and copolymers. The addition of the boehmite nanofillers improved the stiffness without sacrificing high elongation at break. The stiffness, as expressed by Young's modulus, increased with increasing boehmite aspect ratio. In case of thermoplastic elastomer nanocomposites the increase of stiffness was accompanied by a simultaneous increase of elongation at break. According to transmission electron microscopy (TEM), fine dispersion of the polar boehmite nanorods and nanoplatelets within the nonpolar hydrocarbon polymer matrix was obtained without requiring the addition of special dispersing agents or functionalized polyolefin compatibilizers. The comparison of melt compounding of polyethylene with boehmites or polyethylene/boehmite masterbatches revealed that compounding of masterbatches prepared by in situ polymerization filling afforded much finer and more uniform nanoboehmite dispersions. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2755–2765, 2008
N‐vinylcaprolactam‐based microgels: Effect of the concentration and type of cross‐linker
Authors: Imaz Ainara , Forcada Jacqueline
Published: March 2008

New microgel particles produced by using N‐vinylcaprolactam (VCL) and poly(ethylene glycol) diacrylate (PEGDA) or N,N′‐methylenbisacrylamide (BA) were synthesized in a batch reactor. The influence of the concentration and type of crosslinker on polymerization kinetics and colloidal characteristics of such temperature‐sensitive particles was studied. The partial and total conversion evolutions of VCL, PEGDA, and BA were determined by quantitative 1H NMR and the average diameters of microgel particles together with the swelling–deswelling behavior were analyzed by means of photon correlation spectroscopy (PCS). Partial and total conversions, final average diameters at collapsed state, and the swelling–deswelling behavior varied as a function of the type of crosslinker. These results were attributed to the higher solubility and stabilizing ability of PEGDA compared with that of BA. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2766–2775, 2008
Polymerization of 3‐ethynylthiophene with homogeneous and heterogeneous Rh catalysts
Authors: Svoboda Jan , Sedláček Jan , Zedník Jiří , Dvořáková Gita , Trhlíková Olga , Rédrová Dana , Balcar Hynek , Vohlídal Jiří
Published: March 2008

3‐Ethynylthiophene (3ETh) was polymerized with Rh(I) complexes: [Rh(cod)acac], [Rh(nbd)acac], [Rh(cod)Cl]2, and [Rh(nbd)Cl]2 (cod is η2:η2‐cycloocta‐1,5‐diene and nbd η2:η2‐norborna‐2,5‐diene), used as homogeneous catalysts and with the last two complexes anchored on mesoporous polybenzimidazole (PBI) beads: [Rh(cod)Cl]2/PBI and [Rh(nbd)Cl]2/PBI used as heterogeneous catalysts. All tested catalyst systems give high‐cis poly(3ETh). In situ NMR study of homogeneous polymerizations induced with [Rh(cod)acac] and [Rh(nbd)acac] complexes has revealed: (i) a transformation of acac ligands into free acetylacetone (Hacac) occurring since the early stage of polymerization, which suggests that this reaction is part of the initiation, (ii) that the initiation is rather slow in both of these polymerization systems, and (iii) a release of cod ligand from [Rh(cod)acac] complex but no release of nbd ligand from [Rh(nbd)acac] complex during the polymerization. The stability of diene ligand binding to Rh‐atom in [Rh(diene)acac] catalysts remarkably affects only the molecular weight but not the yield of poly(3ETh). The heterogeneous catalyst systems also provide high‐cis poly(3ETh), which is of very low contamination with catalyst residues since a leaching of anchored Rh complexes is negligible. The course of heterogeneous polymerizations is somewhat affected by limitations arising from the diffusion of monomer inside catalyst beads. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2776–2787, 2008
Styrene 4‐vinylbenzocyclobutene copolymer for microelectronic applications
Authors: So Ying‐Hung , Hahn Stephen F. , Li Yongfu , Reinhard Molly T.
Published: March 2008

Styrene and 4‐vinylbenzocyclobutene (vinyl‐BCB) random copolymers were prepared by free radical polymerization and studied for suitability as a dielectric material for microelectronic applications. The percentage of vinyl‐BCB in the copolymer was varied from 0 to 26 mol % to optimize the physical and mechanical properties of the cured copolymer as well as the cost. Copolymer in which 22 mol % of vinyl‐BCB was incorporated along with styrene produced a thermoset polymer which, after cure, did not show a Tg before decomposition at about 350 °C. The polymeric material has a very low dielectric constant, dissipation factor, and water uptake. The fracture toughness of the copolymer was improved with the addition of 20 wt % of a star‐shaped polystyrene‐block‐polybutadiene. Blends of the poly(styrene‐co‐vinyl‐BCB) with the thermoplastic elastomer provided material that maintained high Tg of the cured copolymer with only a slight decrease in thermal stability. The crosslinked styrenic polymer and toughened blends possess many properties that are desirable for high frequency‐high speed mobile communication applications. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2799–2806, 2008
Nonisothermal crystallization and melting behavior of syndiotactic polypropylenes of different microstructure
Authors: Vanegas Ma. Eulalia , Quijada Raúl , Serafini Daniel , Galland Griselda B. , Palza Humberto
Published: March 2008

Syndiotactic polypropylenes and their copolymers with 1‐olefins were synthesized using two metallocene/MAO catalytic systems, and the effect of the different microstructures on nonisothermal crystallization and subsequent melting was studied. Using differential scanning calorimetry (DSC) it was observed that samples with lower content of defects showed crystallization on cooling from the melt, and a double melting peak in the subsequent heating scan, the latter associated with melt, recrystallization and remelt processes that it was confirmed by its nonreversing exothermic process found by means of temperature modulated DSC (MDSC). However, polymers with high amount of defects showed cold crystallization on heating followed by a melting process, that it was observed by MDSC. Wide angle X‐ray diffraction was used for characterizing the changes of crystalline forms in relationship with crystallization process. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 798–806, 2008
Adiabatic runaway reaction, blowdown, quench, and inhibition in fire‐engulfed vessels: An experimental study
Authors: Waldram Simon , Tee Daren , Ladlow Caroline
Published: March 2008

Two linked PHI‐TEC adiabatic calorimeters were used to simulate a fire heating and runaway reaction scenario. This corresponded to plant‐scale continuous flow reactors that are used for the production of acrylamide: two‐phase venting from a fire‐exposed “blocked in” reactor into a dump tank containing water and a chemical inhibitor was simulated. After venting, continuous supplies of electrical power to both the reactor and the quench vessel were maintained so as to simulate sustained fire exposure. The main purpose of the study was to determine whether this venting and continued fire exposure could induce any secondary decomposition reactions. © 2008 American Institute of Chemical Engineers Process Saf Prog, 2008
Optical phase diagram of amorphous carbon films determined by spectroscopic ellipsometry
Authors: Budai J. , Toth Z.
Published: March 2008

In this study we show how amorphous carbon films can be categorized using their optical properties which change according to their structure and composition. Hydrogenated and hydrogen free diamond‐ and graphite‐like carbon films, characterized previously by several methods, were analyzed with spectroscopic ellipsometry in the 1.24‐5 eV photon energy range. To model the measuredΨandΔspectra the optical properties of the films were described with Tauc‐Lorentz oscillator model, Gaussian line shape and Cauchy's dispersion relation. The results and the films are compared in terms of the highest refractive index (nmax) and the corresponding pho‐ ton energy (Emax). When plottingEmaxas a function of the maximal refractive index the data draw out a curved track. The data of different type films are located at different parts of the curve which are placed at corresponding positions for all models. Thus the trends derived with different modeling are the same, even though the optical properties of the films derived from ellipsometric measurements may slightly depend on the applied model. Hence this representation of the refractive index of a‐C and a‐C:H films can be utilized for qualitative analysis. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In‐situ and real‐time investigation of ZnO thin films growth onto rigid and flexible substrates
Authors: Koidis C. , Logothetidis S. , Georgiou D. , Laskarakis A.
Published: March 2008

Zinc Oxide (ZnO) has emerged as one of the most promising TCO materials due to its intrinsic properties. In this work, in‐situ and real‐time Vis‐fUV Spectroscopic Ellipsometry (SE) (1.5‐6.5 eV) has been employed for the monitoring of the growth of ZnO thin films. Films were firstly deposited on Si substrates in order to find the optimum deposition conditions and then to Poly‐Ethylene Terephthalate and Poly‐Ethylene Naphthalate substrates, using the Magnetron Sputtering tech‐ nique. The ability of acquiring real‐time measurements simultaneously and rapidly at 32 wavelengths at the 3‐6.5 eV spectral region, provided accurately the thin films material response. By the analysis of the measured SE spectra, using the appropriate models, it has been determined in detail the time dependence of thickness and optical parameters of the films, providing significant insight on the ZnO growth mechanisms from the early stages of growth. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectroscopic ellipsometry studies of In2S3top window and Mo back contacts in chalcopyrite photovoltaics technology
Authors: Marsillac S. , Barreau N. , Khatri H. , Li J. , Sainju D. , Parikh A. , Podraza N. J. , Collins R. W.
Published: March 2008

Spectroscopic ellipsometry (SE) was used to characterize the conventional back contact layer (Mo) as well as a novel top window layer (In2S3) for use in chalcopyrite photovoltaics technology. For the Mo back contact,in‐situSE measurements of thin films magnetron sputtered onto glass enabled determination ofεat different thicknesses during growth. The observed strong variations could be understood on the basis of a Drude relaxation time that varies with the Mo film thickness. For the In2S3window layer,ex‐situSE measurements showed critical point structures at 2.77±0.08 eV, 4.92±0.005 eV, and 5.64 ± 0.005 eV, as well as an absorption tail with an onset near 1.9 eV. A comparison of the solar cell performance in simulations using either In2S3or conventional CdS revealed similar quantum efficiencies irrespective of the selected window layer. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In situ ellipsometric studies of formation kinetics of rare earth metal conversion coatings on magnesium alloy
Authors: Li Lingjie , Lei Jinglei , Yu Shenghai , He Donghai , Qu Weijuan , Pan Fusheng
Published: March 2008

In situ spectroscopic ellipsometry was employed to investigate the initial regime of rare earth metal (REM) conversion coatings formation on AZ31 magnesium alloy. Three REM salts solutions, 0.05 mol·dm‐3 Ce(NO3)3, La(NO)3 and Sm(NO)3 solutions, were used for REM conversion coatings preparation. By deconvoluting the ellipsometric data, the surface of the fresh well‐polished AZ31 magnesium alloy was found to be covered with 15.80 nm thick native (hydr)oxide film; the refractive indices and the thickness of Ce, La and Sm conversion coatings were obtained. The formation kinetics of three REM coatings follows different exponential functions and the coatings exhibit different optical properties. La conversion coating has the largest n values and the lowest k values while Sm conversion coating is just opposite. Moreover, the pH variation of the bulk conversion solutions upon the coatings formation was recorded. It is confirmed that the reduction of protons leads to the interfacial pH increasing and further results in the precipitation of REM hydroxide gel, which is critical for the REM conversion coatings formation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Infrared ellipsometry studies of thermal stability of protein monolayers and multilayers
Authors: Arwin H. , Askendahl A. , Tengvall P. , Thompson D. W. , Woollam J. A.
Published: March 2008

Methodology for studies of effects of heating multilayers of human serum albumin (HSA) and anti‐HSA is presented. Multilayers of anti‐HSA were prepared on silicon substrates and studied with infrared spectroscopic ellipsometry equipped with a heat stage. The refractive index N = n + ik and the layer thickness are determined and the amide bands are analyzed. It is found that HSA/anti‐HSA multilayers are stable for shorter times at temperatures above 100 °C, except for small thickness changes. Also pilot studies of effects of heating monolayers of proteins adsorbed on gold substrates is presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Development of the VBLaST™: a virtual basic laparoscopic skill trainer
Authors: Maciel Anderson , Liu Youquan , Ahn Woojin , Singh T. Paul , Dunnican Ward , De Suvranu
Published: March 2008

Background

The FLS training tool box has now been adopted by the Society of Gastrointestinal Endoscopic Surgeons (SAGES) as an official training tool for minimally invasive procedures.

Methods

To overcome the limitations of the physical FLS training tool box, we have developed a Virtual Basic Laparoscopic Skill Trainer (VBLaSTTM) system, which is a 3D simulator that will allow trainees to acquire basic laparoscopic skill.

Results

The outcome of this work is the development of an integrated visio‐haptic workstation environment including force feedback devices and a stereo display interface whereby trainees can practice on virtual versions of the FLS. Realistic graphical rendering and high fidelity haptic interactions are achieved.

Conclusions

Surgical skill training is a long and tedious process of acquiring fine motor skills. It is expected that residents would start on trainers such as VBLaSTTM and after reaching a certain level of competence would progress to the more complex trainers for training on specific surgical procedures. Copyright © 2008 John Wiley & Sons, Ltd.
Computer‐assisted implantology: historical background and potential outcomes—a review
Authors: Azari Abbas , Nikzad Sakineh
Published: March 2008

Background

The accurate transfer of preoperatively determined implant positions to the patient mouth is very beneficial to the dental practitioner as well as patients. The objective of this paper was to review the gradual development of computer‐assisted implant surgery.

Methods

All of the major data sources including unpublished data in the internet are considered

Results and Conclusions

Computer‐assisted/‐guided/‐aided implantology has been founded to overcome the errors encountered during implant osteotomies and to position the implants more precisely. The protocols followed by this sophisticated technique are based upon the advocated concept of prosthetic‐driven implantology and CT‐scan analysis recently approved. Although several attempts have been made to improve this approach more and more, little has been done regarding the patient's demands, including cost. The inherent complexity of the techniques and materials utilized necessitates several degrees of training before attempting treatment and must be taken into account. Copyright © 2008 John Wiley & Sons, Ltd.
Oral administration of cyanobacterial bloom extract induced the altered expression of the PP2A, Bax, and Bcl‐2 in mice
Authors: Huang Pu , Zheng Yi‐Fan , Xu Li‐Hong
Published: March 2008

The frequent occurrences of the toxic cyanobacterial (specifically Microcystis aeruginosa) bloom are becoming a global environmental issue. Lots of researches have been focused on the pure cyanobacterial toxins, but little on the natural cyanobacterial bloom. This study was undertaken to investigate the effect of the natural cyanobacterial bloom extract on the expression of proteins, which have been shown to be affected by pure microcystins. In current study, the cyanobacterial bloom extract has been administered orally to ICR mice for 7 days with different dosages. The expression level of PP2A, Bcl‐2, and Bax was measured via western blotting. The results showed that after 7 days of exposure to cyanobacteria extract, in mice liver tissue, the expression level of PP2A andBax was increased significantly between the control and treatment groups, but there is no significant change on the Bcl‐2 expression. This is the first report to describe the altered expression of PP2A in vivo when mice exposure to natural water blooms extract that means many cellular pathways would be interfered via the change of PP2A activity. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008.
Urinary felinine excretion in intact male cats is increased by dietary cystine
Authors: Hendriks Wouter H. , Rutherfurd-Markwick Kay J. , Weidgraaf Karin , Hugh Morton R. , Rogers Quinton R.
Published: March 2008

Felinine is a branched-chain sulfur amino acid present in the urine of certain Felidae, including domestic cats. The objective of the present study was to determine if additional cystine and/or dietaryNwould increase felinine andN-acetylfelinine excretion by intact male cats fed a low-protein (LP) diet. Feeding five adult intact male cats an LP diet (18·8 % of metabolisable energy (ME) as protein)v.a high-protein diet (38·6 % of ME as protein) resulted in a trend (P = 0·08) for decreased urinary felinine and no change inN-acetylfelinine excretion. In a 23 d study, when the LP diet was supplemented withl-cystine at 9·3 g/kg DM, urinary felinine:creatinine ratio showed a linear two-fold (121 %) increase (P < 0·01) from 0·24 (sem0·05) to 0·53 (sem0·13) after 10 d. Subsequent feeding of the LP diet resulted in a decrease in felinine excretion to base levels. Plasma γ-glutamylfelinylglycine concentrations were consistent with the excretion of felinine. Supplementation of the LP diet withl-cystine (9·3 g/kg DM), dispensable amino acids and arginine to a second group (n5) also resulted in a significant (P < 0·01) but smaller (+72 %) increase in the daily felinine:creatinine ratio (0·25 (sem0·04) to 0·43 (sem0·05)). The degree of felinineN-acetylation within groups was unaffected by dietary addition and withdrawal of amino acids. The results indicate that felinine synthesis is regulated by cystine availability, and that arginine may be physiologically important in decreasing felinine biosynthesis in intact male cats.
How reliable and robust are current biomarkers for copper status? – comments by Brewer and Althaus
Authors: Brewer George J. , Althaus John
Published: March 2008

We read the paper by Danzeisen et al.(1) with interest and would like to take issue with the authors on a number of topics.