bluuebunny/crossref_metadata_2025 huggingface dataset:
A finite‐volume particle method for conservation laws on moving domains
Authors: Teleaga D. , Struckmeier J.
Published: March 2008

The paper deals with the finite‐volume particle method (FVPM), a relatively new method for solving hyperbolic systems of conservation laws. A general formulation of the method for bounded and moving domains is presented. Furthermore, an approximation property of the reconstruction formula is proved. Then, based on a two‐dimensional test problem posed on a moving domain, a special Ansatz for the movement of the particles is proposed. The obtained numerical results indicate that this method is well suited for such problems, and thus a first step to apply the FVPM to real industrial problems involving free boundaries or fluid–structure interaction is taken. Finally, we perform a numerical convergence study for a shock tube problem and a simple linear advection equation. Copyright © 2008 John Wiley & Sons, Ltd.
Surrogate model‐based strategy for cryogenic cavitation model validation and sensitivity evaluation
Authors: Goel Tushar , Thakur Siddharth , Haftka Raphael T. , Shyy Wei , Zhao Jinhui
Published: March 2008

The study of cavitation dynamics in cryogenic environment has critical implications for the performance and safety of liquid rocket engines, but there is no established method to estimate cavitation‐induced loads. To help develop such a computational capability, we employ a multiple‐surrogate model‐based approach to aid in the model validation and calibration process of a transport‐based, homogeneous cryogenic cavitation model. We assess the role of empirical parameters in the cavitation model and uncertainties in material properties via global sensitivity analysis coupled with multiple surrogates including polynomial response surface, radial basis neural network, kriging, and a predicted residual sum of squares‐based weighted average surrogate model. The global sensitivity analysis results indicate that the performance of cavitation model is more sensitive to the changes in model parameters than to uncertainties in material properties. Although the impact of uncertainty in temperature‐dependent vapor pressure on the predictions seems significant, uncertainty in latent heat influences only temperature field. The influence of wall heat transfer on pressure load is insignificant. We find that slower onset of vapor condensation leads to deviation of the predictions from the experiments. The recalibrated model parameters rectify the importance of evaporation source terms, resulting in significant improvements in pressure predictions. The model parameters need to be adjusted for different fluids, but for a given fluid, they help capture the essential fluid physics with different geometry and operating conditions. Copyright © 2008 John Wiley & Sons, Ltd.
Risk factors for invasive squamous cell carcinoma of the vulva and vagina—Population‐based case–control study in Denmark
Authors: Madsen Birgitte S. , Jensen Helle L. , van den Brule Adriaan J.C. , Wohlfahrt Jan , Frisch Morten
Published: March 2008

The etiology of vulvar and vaginal squamous cell carcinoma (VV‐SCC) has received little attention. A total of 182 women with invasive VV‐SCC (116 with VV‐SCCvulva, 66 with VV‐SCCvagina), 164 uterine corpus cancer controls and 518 population controls were interviewed in a population‐based case–control study in Denmark, and 87 (48%) of the VV‐SCC cases had tissue samples examined for human papillomavirus (HPV) DNA using the GP5+/6+ PCR‐EIA assay and subsequent reverse line blotting for HPV typing. Logistic regression‐derived odds ratios with 95% confidence intervals served as relative risks. Cervical cancer‐associated high‐risk HPVs (hrHPVs) were detectable in most (89%) examined cases of VV‐SCCvagina and in half (50%) of cases of VV‐SCCvulva (p < 0.001). In site‐specific multivariate logistic regression analyses, statistically significant risk factors for both VV‐SCCvulva and VV‐SCCvagina included measures of hrHPV exposure (anogenital warts for VV‐SCCvulva; cervical neoplasia and poor genital hygiene for VV‐SCCvagina), tobacco smoking and alcohol consumption. Furthermore, socioeconomic variables (marital status and years at school) were associated with risk of VV‐SCCvulva. Comparing hrHPV‐positive and hrHPV‐negative VV‐SCCs in polytomous logistic regression analysis revealed that tobacco smoking and cervical neoplasia were significant risk factors only for hrHPV‐positive VV‐SCCs. Our study shows that VV‐SCCvulva and VV‐SCCvagina share measures of prior hrHPV exposure, tobacco smoking and alcohol consumption as statistically significant risk factors. HPV vaccination programs aimed at reducing the burden of cervical cancers are likely to also provide considerable protection against VV‐SCCs. © 2008 Wiley‐Liss, Inc.
Effect of p53 codon 72 genotype on breast cancer survival depends on p53 gene status
Authors: Xu Ye , Yao Lihua , Zhao Ailian , Ouyang Tao , Li Jinfeng , Wang Tianfeng , Fan Zhaoqing , Fan Tie , Lin Benyao , Lu Youyong , Xie Yuntao
Published: March 2008

In vitro studies suggest that p53 codon 72 genotype alters the apoptotic capacity of p53 protein, with the 72 arginine (R) form of wild‐type p53 harboring a greater apoptosis‐inducing potential than the 72 proline (P) variant. The aim of this study was to investigate whether the association between the p53 codon 72 genotype and breast cancer survival was modified by p53 gene status. In our study, we examined the p53 codon 72 genotype and p53 mutations (through exons 4–9) in paraffin‐embedded specimens from 414 breast cancer patients with a median follow‐up of 8.2 years. We report that the p53 codon 72 genotype was significantly associated with disease‐free survival (DFS, p = 0.02) but not with disease‐specific survival (DSS, p = 0.24) in the entire study population (n = 414). In contrast, the codon 72 genotype was strongly associated with both DFS (p = 0.001) and DSS (p = 0.04) among patients with a wild‐type p53 tumor (n = 346), patients with the P/P variant had worse DFS and DSS than did those with the P/R or R/R variant in this subgroup of patients. More importantly, as compared with the P/R or R/R variant, the P/P variant remained an independent prognostic factor of DFS among patients with a wild‐type p53 tumor (HR = 2.5; 95%CI = 1.4–4.4; p = 0.003). We conclude that the effect of p53 codon 72 genotype on breast cancer survival is dependent on p53 gene status, the P/P variant is strongly associated with poor prognosis among patients with a wild‐type p53 tumor. © 2008 Wiley‐Liss, Inc.
Non‐invasive analysis of cell cycle dynamics in single living cells with Raman micro‐spectroscopy
Authors: Swain Robin J. , Jell Gavin , Stevens Molly M.
Published: March 2008

Raman micro‐spectroscopy is a laser‐based technique which enables rapid and non‐invasive biochemical analysis of cells and tissues without the need for labels, markers or stains. Previous characterization of the mammalian cell cycle using Raman micro‐spectroscopy involved the analysis of suspensions of viable cells and individual fixed and/or dried cells. Cell suspensions do not provide cell‐specific information, and fixing/drying can introduce artefacts which distort Raman spectra, potentially obscuring both qualitative and quantitative analytical results. In this article, we present Raman spectral characterization of biochemical changes related to cell cycle dynamics within single living cells in vitro. Raman spectra of human osteosarcoma cells synchronized in G0/G1, S, and G2/M phases of the cell cycle were obtained and multivariate statistics applied to analyze the changes in cell spectra as a function of cell cycle phase. Principal components analysis identified spectral differences between cells in different phases, indicating a decrease in relative cellular lipid contribution to Raman spectral signatures from G0/G1 to G2/M, with a concurrent relative increase in signal from nucleic acids and proteins. Supervised linear discriminant analysis of spectra was used to classify cells according to cell cycle phase, and exhibited 97% discrimination between G0/G1‐phase cells and G2/M‐phase cells. The non‐invasive analysis of live cell cycle dynamics with Raman micro‐spectroscopy demonstrates the potential of this approach to monitoring biochemical cellular reactions and processes in live cells in the absence of fixatives or labels. J. Cell. Biochem. 104: 1427–1438, 2008. © 2008 Wiley‐Liss, Inc.
Osteoclast inhibitory peptide‐1 (OIP‐1) inhibits measles virus nucleocapsid protein stimulated osteoclast formation/activity
Authors: Shanmugarajan Srinivasan , Youssef Rimon F. , Pati Parmita , Ries William L. , Rao D. Sudhaker , Reddy Sakamuri V.
Published: March 2008

Paget's disease (PD) of bone is characterized by increased activity of large abnormal osteoclasts (OCLs) which contain paramyxoviral nuclear and cytoplasmic inclusions. MVNP gene expression has been shown to induce pagetic phenotype in OCLs. We previously characterized the osteoclast inhibitory peptide‐1 (OIP‐1/hSca) which inhibits OCL formation/bone resorption. OIP‐1 is a glycophosphatidylinositol (GPI)‐linked membrane protein containing a 79 amino acid extra cellular peptide and a 32 amino acid carboxy terminal GPI‐linked peptide (c‐peptide) which is critical for OCL inhibition. In this study, we demonstrate that OIP‐1 c‐peptide significantly decreased (43%) osteoclast differentiation of peripheral blood mononuclear cells from patients with PD. Also, OIP‐1 treatment to normal human bone marrow mononuclear cells transduced with the MVNP inhibited (41%) osteoclast precursor (CFU‐GM) growth in methyl‐cellulose cultures. We further tested if OIP‐1 overexpression in the OCL lineage in transgenic mice inhibits MVNP stimulated OCL formation. MVNP transduction and RANKL stimulation of OIP‐1 mouse bone marrow cells showed a significant decrease (43%) in OCL formation and inhibition (38%) of bone resorption area compared to wild‐type mice. Western blot analysis identified that OIP‐1 decreased (3.5‐fold) MVNP induced TRAF2 expression during OCL differentiation. MVNP or OIP‐1 expression did not affect TRAF6 levels. Furthermore, OIP‐1 expression resulted in a significant inhibition of MVNP stimulated ASK1, Rac1, c‐Fos, p‐JNK, and NFATc1 expression during OCL differentiation. These results suggest that OIP‐1 inhibits MVNP induced pagetic OCL formation/activity through suppression of RANK signaling. Thus, OIP‐1 may have therapeutic utility against excess bone resorption in patients with PD. J. Cell. Biochem. 104: 1500–1508, 2008. © 2008 Wiley‐Liss, Inc.
Protein phosphatase 1 activation and alternative splicing of Bcl‐X and Mcl‐1 by EGCG + ibuprofen
Authors: Kim Myoung H.
Published: March 2008

Epigallocatechin‐3‐gallate (EGCG) and ibuprofen synergistically act to suppress proliferation and enhance apoptosis of prostate cancer cell lines, PC‐3 and LNCaP. The purpose of this study was to investigate the mechanism of underlying this synergism. Most interestingly, EGCG + ibuprofen treatment in PC‐3 cells resulted in altering the ratio of the splice variants of Bcl‐X and Mcl‐1, downregulating the mRNA levels of anti‐apoptotic Bcl‐X(L) and Mcl‐1(L) with a concomitant increase in the mRNA levels of pro‐apoptotic Bcl‐X(s) and Mcl‐1(s). However, there were no apparent changes in splicing variants in either ibuprofen or EGCG treated cells. Induction of alternative splicing was correlated with increased activity of protein phosphatase 1 (PP1) in EGCG + ibuprofen‐treated cells, since pretreatment with calyculin A and tautomycin blocked EGCG + ibuprofen‐induced alternative splicing in PC‐3 cells in contrast to pretreatment with okadaic acid. On the other hand, EGCG + ibuprofen treatment in LNCaP cells did not alter splicing variants of Bcl‐X and Mcl‐1, despite the increase in protein phosphatase activity. In both cell lines, EGCG + ibuprofen inhibited cell proliferation synergistically. Taken together, this study demonstrate for the first time that EGCG + ibuprofen upregulated PP1 activity, which in turn induced alternative splicing of Bcl‐X and Mcl‐1 in a cell‐type specific manner. Our study also demonstrates that the activation of PP1 contributes to the alternative splicing of Mcl‐1. J. Cell. Biochem. 104: 1491–1499, 2008. © 2008 Wiley‐Liss, Inc.
Importance of autophosphorylation at Ser186 in the A‐loop of salt inducible kinase 1 for its sustained kinase activity
Authors: Hashimoto Yoshiko Katoh , Satoh Tomohiro , Okamoto Mitsuhiro , Takemori Hiroshi
Published: March 2008

Autophosphorylation is an important mechanism by which protein kinases regulate their own biological activities. Salt inducible kinase 1 (SIK1) is a regulator in the feedback cascades of cAMP‐mediated gene expression, while its kinase domain also features autophosphorylation activity. We provide evidence that Ser186 in the activation loop is the site of autophosphorylation and essential for the kinase activity. Ser186 is located at the +4 position of the critical Thr residue Thr182, which is phosphorylated by upstream kinases such as LKB1. The relationship between phosphorylation at Ser186 and at Thr182 in COS‐7 cells indicates that the former is a prerequisite for the latter. Glycogen synthase kinase‐3β (GSK‐3β) phosphorylates Ser/Thr residues located at the fourth position ahead of the pre‐phosphorylated Ser/Thr residues, and inhibitors of GSK‐3β reduce the phosphorylation at Thr182. The results of an in vitro reconstitution assay also indicate that GSK‐3β could be the SIK1 kinase. However, overexpression and knockdown of GSK‐3β in LKB1‐defective HeLa cells suggests that GSK‐3β alone may not be able to phosphorylate or activate SIK1, indicating that LKB1 may play a crucial role by phosphorylating SIK1 at Thr182, possibly as an initiator of the autophosphorylation cascade, and GSK‐3β may phosphorylate SIK1 at Thr182 by recognizing the priming‐autophosphorylation at Ser186 in cultured cells. This may also be the case for the other isoform SIK2, but not for SIK3. J. Cell. Biochem. 104: 1724–1739, 2008. © 2008 Wiley‐Liss, Inc.
Selective inhibition of cyclooxygenase‐2 (COX‐2) by 1α,25‐dihydroxy‐16‐ene‐23‐yne‐vitamin D3, a less calcemic vitamin D analog
Authors: Aparna Rachamallu , Subhashini Jagu , Roy Karnati R. , Reddy G. Satyanarayana , Robinson Matthew , Uskokovic Milan R. , Venkateswara Reddy Gorla , Reddanna Pallu
Published: March 2008

Inducible cyclooxygenase‐2 (COX‐2) has been implicated to play a role in inflammation and carcinogenesis and selective COX‐2 inhibitors have been considered as anti‐inflammatory and cancer chemopreventive agents. 1α,25‐dihydroxyvitamin D3 (1α,25(OH)2D3), the active hormonal form of vitamin D3 also has been considered to be a cancer chemopreventive agent in addition to its important role in maintaining calcium homeostasis. Based on these observations, we studied the direct effect of 1α,25(OH)2D3 and one of its less calcemic synthetic analogs, 1α,25(OH)2‐16‐ene‐23‐yne‐D3 on the activity of both COX‐1 and COX‐2 in an in vitro enzyme assay. Preliminary data indicated that both 1α,25(OH)2D3 and 1α,25(OH)2‐16‐ene‐23‐yne‐D3 inhibited selectively the activity of COX‐2 with no effect on the activity of COX‐1. Out of the two compounds, 1α,25(OH)2‐16‐ene‐23‐yne‐D3 was found to be more effective with an IC50 of 5.8 nM. Therefore, the rest of the experiments were performed using 1α,25(OH)2‐16‐ene‐23‐yne‐D3 only. 1α,25(OH)2‐16‐ene‐23‐yne‐D3 inhibited the proliferation of lipopolysaccharide (LPS) stimulated mouse macrophage cells (RAW 264.7) with a reduction in the expression of COX‐2 along with other inflammatory mediators like inducible nitric oxide synthase (iNOS) and interleukin‐2 (IL‐2). Furthermore, 1α,25(OH)2‐16‐ene‐23‐yne‐D3 also inhibited carrageenan induced inflammation in an air pouch of a rat and effectively reduced the expression of COX‐2, iNOS, and IL‐2 in the tissues of the same air pouch. In both cases, 1α,25(OH)2‐16‐ene‐23‐yne‐D3 did not show any effect on the expression of COX‐1. In summary, our results indicate that 1α,25(OH)2‐16‐ene‐23‐yne‐D3, a less calcemic vitamin D analog, exhibits potent anti‐inflammatory effects and is a selective COX‐2 inhibitor. J. Cell. Biochem. 104: 1832–1842, 2008. © 2008 Wiley‐Liss, Inc.
Effect of [Cl−]i on ENaC activity from mouse cortical collecting duct cells
Authors: Gu Yuchun
Published: March 2008

Na+ transport via epithelial Na+ channel (ENaC) occurs across many epithelial surfaces and plays a key role in regulating salt and water absorption. In this study, we have examined the effects of cytosolic Na+ and Cl− on ENaC activity by patch clamping single channel recording method in mouse cortical collecting duct cells (M1). Cytosolic Na+ exerts its effect in change of ENaC open probability (Po). High cytosolic Na+ significantly reduces ENaC Po. No change in channel conductance by cytosolic Na+ is observed. However, decrease of cytosolic Cl− concentration significantly increases channel conductance and ENaC Po. This effect is due to the right shift of ENaC I–V curve to positive membrane potential. The virtue of ENaC conductance remains the same. Cl− channels like CFTR and VRAC are unlikely to be involved in this regulation. The results suggest that cytosolic Cl− could serve as a mediator to regulate ENaC activity, in accordance with the activities of Cl− channels. J. Cell. Physiol. 216: 453–457, 2008. © 2008 Wiley‐Liss, Inc.
Acrylonitrile‐butadiene‐styrene nanocomposites filled with nanosized alumina
Authors: Kar Kamal K. , Srivastava S. , Rahaman Ariful , Nayak S.K.
Published: March 2008

A polymer nanocomposite was produced by acrylonitrile‐butadiene‐styrene (ABS) and α‐alumina was prepared through sol‐gel process using aluminum nitrate and citric acid. The particle size was analyzed by X‐ray diffraction and scanning electron microscopy (SEM) studies. The nanocomposites were characterized through tensile strength, Young's modulus, strain% at break, flexural strength, flexural modulus, and impact strength. The ABS/Al2O3 nanocomposites are found to have slightly higher Young's modulus, but lower tensile strength, strain% at break, flexural and impact strength than the virgin ABS. But its flexural modulus increases with increasing Al2O3 content in ABS matrix. The d‐spacing was calculated in nanocomposites to evaluate the interaction between Al2O3 and ABS. The particle distributions in nanocomposites were studied by SEM. The fractured surfaces of tensile test samples were also examined through SEM and show that the ductile fracture of ABS is converted to brittle fracture with addition of Al2O3. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
The unidirectional glass fiber reinforced furfuryl alcohol for pultrusion. I. Process feasibility and kinetic analysis
Authors: Chen Chin‐Hsing , Chen I‐Ken
Published: March 2008

The development of unidirectional glass fiber reinforced furfuryl alcohol (FA) composites has been conducted using an in situ polymerization method. The FA prepolymer synthesized in this study was prepared from blends of FA monomer and catalyst (p‐toluene sulfonic acid). The process feasibility, and kinetic analysis of the unidirectional glass fiber reinforced FA composites by pultrusion has been investigated. From the investigations of the long pot life of FA prepolymer, the high reactivity of FA and FA/glass fiber, and excellent fiber wet‐out of FA resin and glass fiber, it was found that the FA resin showed excellent process feasibility for pultrusion. A kinetic autocatalytic model, dα/dt = A exp(−E/RT)αm(1−α)n, was proposed to describe the curing behavior of FA/glass fiber composites. Kinetic parameters for the model were obtained from dynamic differential scanning calorimetry scans using a multiple regression technique. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
A new controllable approach to synthesize hyperbranched poly(siloxysilanes)
Authors: Wang Sheng‐Jie , Fan Xiao‐Dong , Kong Jie , Wang Xin , Liu Yu‐Yang , Zhang Guo‐Bin
Published: March 2008

A new controllable approach to synthesize hyperbranched poly(siloxysilanes) via hydrosilylation of A2‐ and B′Bx‐type monomers was developed in this work. A2 monomers (dimethylbis(dimethylsiloxy)siloxane and tetramethyldisiloxane), B′Bx monomers (methylvinyldiallylsilane and vinyltriallylsilane), and the resultant hyperbranched poly(siloxysilanes) were well characterized using FTIR, 1H NMR, 13C NMR, 29Si NMR, and SEC/MALLS. The In situ FTIR results indicate that the controllable polymerization can be carried out quickly and the reaction process was obviously performed in two stages. At the first stage, silicon hydride selectively reacts with vinyl silane groups, which produces intermediate structures with one SiH and two (or three) allyl groups. Consequently, at the second stage, these intermediates act as new AB2 (or AB3) type monomers and continue to be self‐polymerized to generate hyperbranched polymers. By this novel controllable approach, molecular weights and their polydispersity of the resulted hyperbranched poly(siloxysilanes) can be conveniently regulated via adjusting the process parameters, such as feeding ratio of two monomers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2708–2720, 2008
Iterative tandem catalysis of racemic AB monomers
Authors: Kanca üMit , Van Buijtenen Jeroen , Van As Bart A. C. , Korevaar Peter A. , Vekemans Jef A. J. M. , Palmans Anja R. A. , Meijer E. W.
Published: March 2008

Racemic AB monomers encompassing a secondary hydroxy group and a methyl ester moiety were synthesized and converted to chiral polyesters by iterative tandem catalysis (ITC). The concurrent action of an enantioselective acylation catalyst (Novozym 435) and a racemization catalyst (Ru(Shvo)) results in the high conversion of the racemic monomers to enantio‐enriched polymers. Several factors are important for attaining high ee's and high molecular weights. The enantioselectivities observed for the novel AB monomers by Novozym 435 are high enough at 70 °C (E ratio ≥ 200) for the monomers to be useful for ITC. ITC of methyl 6‐hydroxyheptanoate showed that a catalyst loading of ∼1.4 mol % Ru(Shvo), 25 mg Novozym 435/mmol AB monomer, and 0.5 mmol DMP/mmol monomer employing a monomer concentration of 1 mol/L gave a monomer conversion of 94%, an ee of 91%, and an Mp of 6.0 kg/mol. Application of these conditions to the other AB monomers revealed the sensitivity of the system. Reduced enantioselectivities were observed when longer reaction times were required for attaining high conversions. These long reaction times were necessary due to the slow (or absent) racemization activity of the Ru(Shvo) catalyst as a result of catalyst deactivation. Since quantitative conversions are crucial to attain high molecular weight polymers in polycondensation reactions, we could significantly improve the system by switching to isopropyl esters of the AB monomers and/or by strict exclusion of oxygen during the ITC. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2721–2733, 2008
Synthesis, characterization, and fluorescence of pyrene‐containing eight‐arm star‐shaped dendrimer‐like copolymer with pentaerythritol core
Authors: Yuan Weizhong , Yuan Jinying , Zhou Mi , Pan Caiyuan
Published: March 2008

Novel and well‐defined pyrene‐containing eight‐arm star‐shaped dendrimer‐like copolymers were successfully achieved by combination of esterification, atom transfer radical polymerization (ATRP), divergent reaction, ring‐opening polymerization (ROP), and coupling reaction on the basis of pentaerythritol. The reaction of pentaerythritol with 2‐bromopropionyl bromide permitted ATRP of styrene (St) to form four‐arm star‐shaped polymer (PSt‐Br)4. The molecular weights of these polymers could be adjusted by the variation of monomer conversion. Eight‐hydroxyl star‐shaped polymer (PSt‐(OH)2)4 was produced by the divergent reaction of (PSt‐Br)4 with diethanolamine. (PSt‐(OH)2)4 was used as the initiator for ROP of ε‐caprolactone (CL) to produce eight‐arm star‐shaped dendrimer‐like copolymer (PSt‐b‐(PCL)2)4. The molecular weights of (PSt‐b‐(PCL)2)4 increased linearly with the increase of monomer. After the coupling reaction of hydroxyl‐terminated (PSt‐b‐(PCL)2)4 with 1‐pyrenebutyric acid, pyrene‐containing eight‐arm star‐shaped dendrimer‐like copolymer (PSt‐b‐(PCL‐pyrene)2)4 was obtained. The eight‐arm star‐shaped dendrimer‐like copolymers presented unique thermal properties and crystalline morphologies, which were different from those of linear poly(ε‐caprolactone) (PCL). Fluorescence analysis indicated that (PSt‐b‐(PCL‐pyrene)2)4 presented slightly stronger fluorescence intensity than 1‐pyrenebutyric acid when the pyrene concentration of them was the same. The obtained pyrene‐containing eight‐arm star‐shaped dendrimer‐like copolymer has potential applications in biological fluorescent probe, photodynamic therapy, and optoelectronic devices. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2788–2798, 2008
Structure and properties of poly(ethylene terephthalate)/Na+‐montmorillonite nanocomposites prepared by solid state shear milling (S3M) method
Authors: Wang Guoli , Chen Yinghong , Wang Qi
Published: March 2008

This article reported a novel technology, solid state shear milling (S3M), to prepare poly(ethylene terephthalate)/Na+‐montmorillonite nanocomposites using the pristine Na+‐MMT without organic modification so as to avoid the problem that the organic modifiers, used for MMT treatment will decompose at high processing temperature of PET, and the structure and properties of the obtained samples were investigated. XRD and TEM analyses showed that Na+‐MMT layers were partially delaminated and intercalated, and uniformly dispersed in the PET matrix when suffering from the strong three dimensional shearing forces of pan‐milling. DSC analysis showed that Na+‐MMT serves as a nucleating agent, increasing the crystallization rate as well as the crystallization temperature of PET. The properties such as thermal stability and tensile strength of the PET/Na+‐MMT nanocomposites prepared by S3M got remarkably improved. Solid state shear milling (S3M) method was a simple and efficient method to get polymer/Na+‐MMT nanocomposites with pretty good performances without organic modification of pristine Na+‐MMT. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 807–817, 2008
Development of a process safety culture of chemical engineers
Authors: Mckay Maxime , Lacoursière J.P.
Published: March 2008

Chemical engineers are frequently responsible for designing and operating process facilities. These facilities could cause major accidents with consequences on site and off site. Equilibrium has to be maintained between production pressure and safety requirements. This equilibrium can only be achieved if the people involved with the process plant develop and maintain a strong process safety culture. Lessons from the Challenger, Columbia, BP Texas City accidents, etc. indicate that there are five important key organization culture themes that need to be taken into account:

Maintain sense of vulnerability

Establish an imperative for safety

Perform valid/timely hazard/risk assessments

Ensure open and frank communications

Learn and advance the culture

This paper will describe how a chemical engineer can integrate these as a safety roadmap. © 2008 American Institute of Chemical Engineers Process Saf Prog, 2008
Facile synthesis of large scale Er‐doped ZnO flower‐like structures with enhanced 1.54 μm infrared emission
Authors: Yang Wei‐Chieh , Wang Chun‐Wen , He Jr‐Hau , Chang Yu‐Cheng , Wang Jen‐Cheng , Chen Lih‐Juann , Chen Hung‐Ying , Gwo Shangir
Published: March 2008

A new strategy to introduce metallic dopant into ZnO structures by a wet chemical reaction is presented. Single‐crystal Er‐doped ZnO flower‐like structures have been synthesized on ZnO‐coated silicon substrate by a low temperature hydrothermal process. The Er‐doped ZnO structures exhibit promising 1.54 μm photoluminescence emission for optoelectronic communication. The successful doping has been confirmed by the X‐ray diffraction, transmission electron microscopy, X‐ray photoemission spectroscopy and photoluminescence measurements. The achievement to introduce Er dopants into ZnO flower‐like structures by the time‐ and cost‐effective wet chemical reaction at low temperature for the first time has vast potential to scale up for possible applications. The photoluminescence properties are significantly improved compared to that reported in the literature for the Er‐doped nanowires and thin films and shall be much more applicable in optical and communication devices. The flower‐like structures are expected to be advantageous in serving as a multi‐directional infrared emitters and/or detectors. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Introducing crystalline rare‐earth oxides into Si technologies
Authors: Osten H. J. , Laha A. , Czernohorsky M. , Bugiel E. , Dargis R. , Fissel A.
Published: March 2008

The ability to integrate crystalline metal oxide dielectric barrier layers into silicon structures can open the way for a variety of novel applications which enhances the functionality and flexibility ranging from high‐K replacements in future MOS devices to oxide/silicon/oxide heterostructures for nanoelectronic application in quantum‐effect devices. We present results for crystalline gadolinium oxides on silicon in the cubic bixbyite structure grown by solid source molecular beam epitaxy. Additional oxygen supply during growth improves the dielectric properties significantly. Experimental results for Gd2O3‐based MOS capacitors grown under optimized conditions show that these layers are excellent candidates for application as very thin high‐K materials replacing SiO2 in future MOS devices. Epitaxial growth of lanthanide oxides on silicon without any interfacial layer has the advantage of enabling defined interfaces engineering. We will show that the electrical properties of epitaxial Gd2O3 thin films on Si substrates can further be improved significantly by an atomic control of interfacial structures. Finally, we will present a new approach for nanostructure formation which is based on solid‐phase epitaxy of the Si quantum‐well combined with simultaneous vapor‐phase epitaxy of the insulator on top of the quantum‐well. Ultra‐thin single‐crystalline Si buried in a single‐crystalline insulator matrix with sharp interfaces was obtained by this approach on Si(111). In addition, structures consisting of a single‐crystalline oxide layer with embedded Si nanoclusters for memory applications will also be demonstrated. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tunneling phenomena in carbon nanotube field‐effect transistors
Authors: Knoch Joachim , Appenzeller Joerg
Published: March 2008

In the present article we will discuss the electronic trans‐ port properties of carbon nanotube field‐effect transistors (CNFETs). Three different device concepts will be studied in more detail: Schottky‐barrier CNFETs with metallic source and drain contacts, conventional‐type CNFETs with doped nanotube segments as source and drain electrodes and finally a new concept, the tunneling CNFET. As it turns out, tunneling phenomena play a prominent role in all three CNFET designs and determine their electrical behavior to a large extend. In addition, the one‐dimensionality of the electronic transport makes them ideally suited for novel device architecture such as the tunneling CNFET. Analytical as well as simulation results will be given and compared with each other and with experimental data in order to explain the different influences on the electronic transport in CNFETs and thus on the device behavior. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of the free charge carrier properties at the ZnO‐sapphire interface in a‐plane ZnO films studied by generalized infrared ellipsometry
Authors: Sturm C. , Chavdarov T. , Schmidt‐Grund R. , Rheinländer B. , Bundesmann C. , Hochmuth H. , Lorenz M. , Schubert M. , Grundmann M.
Published: March 2008

The free charge carrier properties at the film‐substrate interface of non‐polar ZnO films were investigated by generalized infrared spectroscopic ellipsometry in dependence on film thickness and annealing time. For all samples a highly‐conductive film‐substrate interface layer was found. It was observed that the charge density at the interface increases with increasing film thickness and decreases with increasing annealing time. Possible explanations could be the diffusion of Al from the substrate into the ZnO film, the formation of zinc aluminate, or structural changes, respectively. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Immunodetection using computer screen photo‐assisted ellipsometry
Authors: Bakker J. W. P. , Arwin H. , Lundström I. , Filippini D.
Published: March 2008

Detection of antibody‐antigen reactions is demonstrated by measuring changes in reflectance of light polarized parallel to the plane of incidence, using a computer screen as light source and a web camera as detector, giving results similar to traditional off‐null ellipsometry and in accordance with a simplified theoretical model. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of ion track and shapes with damage simulations on the base of ellipsometric and backscattering spectrometric measurements
Authors: Polgár O. , Fried M. , Khanh N. , Petrik P. , Bársony I.
Published: March 2008

On the base of geometrical and statistical considerations a damage simulator was created in order to determine the ion track‐radius and ‐shape of ion‐implantation caused damage in single‐crystalline Si. Damage vs. dose curves calculated by spectroscopic ellipsometry (SE) and Rutherford backscattering/channeling spectrometry (RBS/C) measurements, using different doses of 100 keV Xe implantation, gave information about the damage profile in depth. Both methods are required, because of dose‐dependent discrepancies of SE compared with RBS/C [Fried et al., Thin Solid Films 455/456, 404 (2004)]. Different kinds of damage models were investigated to calculate the ion track‐radius and to describe the damages in depth and the shape of ion track. Comparing directly the simulated and the measured damage vs. dose curves, the damage function and the other simulation parameters were optimized and hence the ion track size and even the shape can be determined. The dose dependent mean size of the unchanged crystalline regions, obtained from the simulation was correlated with the complex dielectric functions, obtained from the SE analysis. The results clearly show the effect of decreasing size of the unchanged crystalline regions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural and optical properties of ZrO2 and Al2O3 thin films and Bragg reflectors grown by pulsed laser deposition
Authors: Sellmann J. , Sturm Ch. , Schmidt‐Grund R. , Czekalla Ch. , Lenzner J. , Hochmuth H. , Rheinländer B. , Lorenz M. , Grundmann M.
Published: March 2008

ZrO2‐Al2O3 Bragg reflectors for future application in ZnO based resonators grown by pulsed laser deposition on c‐plane sapphire and silicon substrates show a reflectivity up to 99.8% with a layer pair number of 12.5. Layer thicknesses obtained from standard ellipsometry agree very well with thicknesses observed by transmission scanning electron microscopy. A very smooth surface roughness of Ra = 0.5 nm was observed for these Bragg reflectors. ZnO thin films grown on bulk c‐plane sapphire and on Bragg reflectors revealed comparable high photoluminescence intensity. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of heteroepitaxy on nanoscopically roughened (001)Si by real‐time spectroscopic polarimetry
Authors: Liu X. , Kim I.‐K. , Aspnes D. E.
Published: March 2008

We use a real‐time spectroscopic polarimeter integrated with an organometallic chemical vapor deposition system to investigate growth of GaP on Si, and particularly nanoscopically roughened (nr‐)Si. We find nanoroughening is necessary to increase the density of nucleation sites and decrease reactant mobility and thereby grow continuous films instead of widely spaced islands. The nrSi surfaces are more highly reactive to the trimethylgallium precursor than III‐V growth surfaces, leading to the appearance of metallic Ga if standard growth conditions are used in the initial phase of heteroepitaxy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of ion concentration on refractive indices of fluids measured by the minimum deviation technique
Authors: Berlind T. , Pribil G. K. , Thompson D. , Woollam J. A. , Arwin H.
Published: March 2008

The prism minimum deviation technique has been used to measure the fluid dependence of refractive indices. Fluids with varying ion concentration (0 to 1.0 M) and varying protein concentration (0.01‐10 mg/ml) have been examined and the measurements show that these parameters influence the refractive index values. Also it is shown by simulations that it is important to take the change of refractive index of the fluid into account when evaluating insitu protein adsorption measurements. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conceptualizations of argumentation from science studies and the learning sciences and their implications for the practices of science education
Authors: Bricker Leah A. , Bell Philip
Published: March 2008

Argumentation has become an increasingly recognized focus for science instruction‐‐‐as a learning process, as an outcome associated with the appropriation of scientific discourse, and as a window onto the epistemic work of science. Only a small set of theoretical conceptualizations of argumentation have been deployed and investigated in science education, however, while a plethora of conceptualizations have been developed in the interdisciplinary fields associated with science studies and the learning sciences. This paper attempts to review a range of such theoretical conceptualizations of argumentation and discuss the possible implications for the orchestration of science education; the goal being that the science education research community might consider a broader range of argumentation forms and roles in conjunction with the learning of science. © 2008 Wiley Periodicals, Inc.Sci Ed92:473–493, 2008
Demotivators of software process improvement: an empirical investigation
Authors: Niazi Mahmood , Ali Babar Muhammad , Katugampola Nolin Mark
Published: March 2008

We have conducted an empirical study with 23 Vietnamese software practitioners to determine Software Process Improvement (SPI) demotivators. We have compared the demotivators identified by the Vietnamese practitioners with the demotivators identified by UK practitioners. The main objective of this study is to provide SPI managers with insight into the nature of factors that can hinder the success of a SPI program, so that SPI managers can better manage those demotivators to maximize practitioners' support for an SPI program.

We used face‐to‐face questionnaire‐based survey sessions for gathering data. We also asked the participants to rank each identified SPI demotivator on a five‐point scale (high, medium, low, zero or do not know) to determine the perceived importance of each demotivator. From this, we proposed the notion of ‘perceived value’ associated with each identified demotivator.

Our findings identify the ‘high’ and ‘medium’ perceived value demotivators that can undermine SPI initiatives. The findings also show that there are differences in SPI demotivators across practitioners' groups (i.e., developers and managers) and across organisational sizes (i.e. large and small‐to‐medium). Moreover, our results reveal the similarities and differences between SPI demotivators as perceived by practitioners in Vietnam and the United Kingdom. The findings are expected to provide SPI managers with insight to design and implement suitable strategies to deal with the identified SPI demotivators. Copyright © 2008 John Wiley & Sons, Ltd.
Effects of 2,4‐dichlorophenol on the expression of vitellogenin and estrogen receptor genes and physiology impairments in Chinese rare minnow (Gobiocypris rarus)
Authors: Zhang Xiaoyan , Zha Jinmiao , Li Wei , Yang Lihua , Wang Zijian
Published: March 2008

2,4‐Dichlorophenol (2,4‐DCP) is known as a toxicant, but unknown as an environmental endocrine disruptor. In the present work, Chinese rare minnow (Gobiocypris rarus) was exposed to 0.03, 0.3, and 3 mg/L 2,4‐DCP for 3 d and 0.1, 0.3, and 1 mg/L 2,4‐DCP for 21 d, respectively. Endpoints including somatic index, vitellogenin (VTG) mRNA and protein level, estrogen receptor (ER) mRNA and histopathology were measured. In the 3‐d exposure experiment, the effect concentrations were 0.3 mg/L and above, and in 21‐d exposure, the effect concentrations were 0.1 mg/L and above. When exposed to the effect concentrations, GSI was significantly reduced for both male and female, ER mRNA was upregulated in male and downregulated in female. There were no significant variations of VTG mRNA in both male and female in 3‐d exposure and in male in 21‐d exposure. However, VTG mRNA in female in 21‐d exposure was upregulated, corresponding to an increase of VTG protein in serum. Histopathological observation showed that ovaries were degenerated in the effect concentrations, where follicular atresias were more frequently observed. Because the sex hormones related genes and toxicological endpoints were affected in the dose‐dependent manner, the results suggest that 2,4‐DCP could be a potential endocrine disruptor and might cause adverse effects in female sex organs through interruption of ER‐mediated processes. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008.
Oxygen decline in biotesting of environmental samples—Is there a need for consideration in the acute zebrafish embryo assay?
Authors: Küster Eberhard , Altenburger Rolf
Published: March 2008

Environmental samples such as groundwater, sediment pore water, native or freeze dried sediments may be difficult to analyze for toxic effects with organismic aquatic bioassays. These samples might evoke low oxygen concentration or oxygen depletion during the test. The toxicity assessment could thus be confounded by low oxygen concentrations. The acute zebrafish embryo assay was used to analyze the influence of oxygen deficit on the embryonic development in the first 48 h post fertilization. Embryos were exposed to varying oxygen concentrations ranging from <30 to >80% oxygen saturation of water. A clear concentration dependent retardation of fish embryo development was observed. Because of a retarded development toxic thresholds of environmental samples which might include substances slowing down the development will be altered. For the purpose of identification of critical contaminants in complex environmental samples, it is proposed to actively aerate environmental samples which are likely to be oxygen depleted during the duration of the zebrafish embryo bioassay. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008.
New charts for ultrasound dating of pregnancy and assessment of fetal growth: longitudinal data from a population‐based cohort study
Authors: Verburg B. O. , Steegers E. A. P. , De Ridder M. , Snijders R. J. M. , Smith E. , Hofman A. , Moll H. A. , Jaddoe V. W. V. , Witteman J. C. M.
Published: March 2008

Objectives

Correct assessment of gestational age and fetal growth is essential for optimal obstetric management. The objectives of this study were, first, to develop charts for ultrasound dating of pregnancy based on crown–rump length and biparietal diameter and, second, to derive reference curves for normal fetal growth based on biparietal diameter, head circumference, transverse cerebellar diameter, abdominal circumference and femur length from 10 weeks of gestational age onwards.

Methods

A total of 8313 pregnant women were included for analysis in this population‐based prospective cohort study. All women had repeated ultrasound assessments to examine fetal growth.

Results

Charts for ultrasound dating of pregnancy, based on crown–rump length and biparietal diameter, were derived. Internal validation with the actual date of delivery showed that ultrasound imaging provided reliable gestational age estimates. Up to 92% of deliveries took place within 37–42 weeks of gestation if gestational age was derived from ultrasound data, compared with 87% based on a reliable last menstrual period. The earlier the ultrasound assessment the more accurate the prediction of date of delivery. After 24 weeks of gestation a reliable last menstrual period provided better estimates of gestational age. Reference curves for normal fetal growth from 10 weeks of gestational age onwards were derived.

Conclusions

Charts for ultrasound dating of pregnancy and reference curves for fetal biometry are presented. The results indicate that, up to 24 weeks of pregnancy, dating by ultrasound examination provides a better prediction of the date of delivery than does last menstrual period. The earlier the ultrasound assessment in pregnancy, preferably between 10 and 12 weeks, the better the estimate of gestational age. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Prognostic Factors and Availability of D2 Lymph Node Dissection for the Patients with Stage II Gastric Cancer: Comparative Analysis of Subgroups in Stage II
Authors: Park Joong‐Min , Kim Jong‐Han , Park Sung‐Soo , Kim Seung‐Joo , Mok Young‐Jae , Kim Chong‐Suk
Published: March 2008

Background

According to the fifth edition of the UICC TNM classification, stage II gastric cancer has three subgroups: T1N2M0, T2N1M0, and T3N0M0. This study was designed to investigate the prognosis of stage II gastric cancer according to the T and N category to verify the accuracy of TNM staging for stage II and to determine the prognostic factors for patients with stage II gastric cancer by subgroup.

Methods

Clinicopathologic data from 326 patients with stage II gastric cancer were studied. We stratified the patients into T2N1 and T3N0 groups and performed comparative analysis between the two groups as well as univariate and multivariate survival analyses for each group.

Results

The five‐year survival rate for patients with T2N1 disease was 75.6%, whereas for patients with T3N0 disease it was 68.3%. There was no significant difference in survival between T2N1 and T3N0 groups (p = 0.174). Univariate survival analysis showed that age, gender, histological type, and the extent of lymph node dissection were significant prognostic factors for stage II gastric cancer. However, multivariate analysis demonstrated that only gender and the extent of lymph node dissection were significant variables. Among these variables, gender was an independent prognostic factor for survival only in the T2N1 group. On the other hand, the extent of lymph node dissection was an independent prognostic factor in the T3N0 group, not in the T2N1 group.

Conclusions

There was no significant difference in survival between the T2N1 and the T3N0 groups. Thus, our data support the accuracy of the TNM staging classification for stage II gastric cancer. We found a significant survival benefit with D2 dissection for T3N0 but not T2N1. However, before recommending limited lymph node dissection for T2N1 stage disease, development of a preoperative method for prediction of depth of invasion and lymph node status is needed.
Experiences of Teens Living in the Shadow of Huntington Disease
Authors: Sparbel Kathleen J. H. , Driessnack Martha , Williams Janet K. , Schutte Debra L. , Tripp‐Reimer Toni , McGonigal‐Kenney Meghan , Jarmon Lori , Paulsen Jane S.
Published: March 2008

Research on families with Huntington Disease (HD) has primarily focused on adult decision‐making surrounding predictive genetic testing and caregiver stress. Little is known about the experiences of teens living in these families. This qualitative study explored the experiences of 32 teens living in families with HD. Six focus groups were conducted across the U.S. and Canada. Data were analyzed using descriptive qualitative analysis. Huntington disease appeared to cast a shadow over the experiences described by teens. Four themes were identified: watching and waiting; alone in the midst of others; family life is kind of hard; and having to be like an adult. These experiences highlight the need for genetic counselors, health care providers, and school personnel to be aware of issues facing teens living in families with HD. Recognizing patterns of teen experiences may help health care providers develop strategies to support coping by teens in HD families.