bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of a secretory protein c19orf10 activated in hepatocellular carcinoma
Authors: Sunagozaka Hajime , Honda Masao , Yamashita Taro , Nishino Ryuhei , Takatori Hajime , Arai Kuniaki , Yamashita Tatsuya , Sakai Yoshio , Kaneko Shuichi
Published: December 2010

The identification of genes involved in tumor growth is crucial for the development of inventive anticancer treatments. Here, we have cloned a 17‐kDa secretory protein encoded by c19orf10 from hepatocellular carcinoma (HCC) serial analysis of gene expression libraries. Gene expression analysis indicated that c19orf10 was overexpressed in approximately two‐thirds of HCC tissues compared to the adjacent noncancerous liver tissues, and its expression was significantly positively correlated with that of alpha‐fetoprotein (AFP). Overexpression of c19orf10 enhanced cell proliferation of AFP‐negative HLE cells, whereas knockdown of c19orf10 inhibited cell proliferation of AFP‐positive Hep3B and HuH7 cells along with G1 cell cycle arrest. Supplementation of recombinant c19orf10 protein in culture media enhanced cell proliferation in HLE cells, and this effect was abolished by the addition of antibodies developed against c19orf10. Intriguingly, c19orf10 could regulate cell proliferation through the activation of Akt/mitogen‐activated protein kinase pathways. Taken together, these data suggest that c19orf10 might be one of the growth factors and potential molecular targets activated in HCC.
FoxO1: A molecule for all seasons
Authors: Kousteni Stavroula
Published: December 2010

The FoxO family of forkhead transcription factors is at the crossroads of many signal transduction pathways that are evolutionarily conserved. Such pathways have been co-opted in differentiated tissues for a variety of vital and specialized functions, such as differentiation, proliferation, and survival in cells as diverse as adipocytes, hepatocytes, β-cells, myoblasts, thymocytes, and cancer cells. FoxO metabolic functions are relevant to glucose metabolism, tumor suppression, hematopoiesis, angiogenesis, and antioxidant defense. Among the FoxO isoforms, FoxO1 is a main target of insulin signaling and regulates metabolic homeostasis and organismal survival at many different levels. FoxO1 entered into the field of skeletal biology by a property that is unique among its functions in other organs. With the osteoblast as its target cell, FoxO1 not only acts on it to regulate bone homeostasis but also through it as a transcriptional modulator of the endocrine function of the skeleton in regulating glucose metabolism. Through its direct skeletal actions, FoxO1 promotes osteoblast proliferation by maintaining protein synthesis and redox balance. Through its endocrine actions on target tissues of insulin, FoxO1 acts by way of osteocalcin to suppress glucose production by pancreatic beta cells and hepatocytes and to decrease insulin production and sensitivity. These two parallel but opposing actions, one in favor of the skeleton and the other in disadvantage of glucose-regulating tissues, may signify an adaptive mechanism that integrates responses between different organs and is beneficial for whole-body physiology during stress and aging. © 2011 American Society for Bone and Mineral Research.
Expectations
Authors: Constantino Michael J. , Arnkoff Diane B. , Glass Carol R. , Ametrano Rebecca M. , Smith JuliAnna Z.
Published: December 2010

Patients' expectations have long been considered a contributory factor to successful psychotherapy. Expectations come in different guises, with outcome expectations centered on prognostic beliefs about the consequences of engaging in treatment. In this article, we define outcome expectations and present assessment methods and clinical examples of outcome expectations. Our research review includes a comprehensive meta‐analysis (N =8,016 patients across 46 independent samples) of the association between pretherapy or early‐therapy outcome expectations and posttreatment outcomes. The overall weighted effect size was d=.24, p<.001, indicating a small but significant positive effect of outcome expectations on adaptive treatment outcomes. We also provide a narrative review of mediators of the expectation‐outcome link and patient factors that relate to their outcome expectations. Finally, we discuss limitations of the research base and offer therapeutic practices based on our findings. © 2010 Wiley Periodicals, Inc. J Clin Psychol: In Session 67:184–192, 2011.
Working to make it work: the role of parents in the youth mentoring process
Authors: Spencer Renée , Basualdo‐Delmonico Antoinette , Lewis Terrence O.
Published: December 2010

Theoretical and empirical work on youth mentoring relationships has been largely focused on the mentor‐youth dyad, with little attention to the larger context within which such relationships form and develop. The perspectives of parents have been absent for the most part from the mentoring literature to date. In‐depth, semistructured, qualitative interviews were conducted with parents (n=13) of youth who were participating in a community‐based mentoring program. Four major themes were identified: parents' (a) hopes and expectations for the mentoring relationship, (b) trust in the mentor and satisfaction with the relationship, (c) roles in the mentoring relationship, and (d) reflections on and experiences with cultural differences between their child and the mentor. © 2010 Wiley Periodicals, Inc.
Associations between mothers' experience with the troubles in Northern Ireland and mothers' and children's psychological functioning: the moderating role of social identity
Authors: Merrilees Christine E. , Cairns Ed , Goeke‐Morey Marcie C. , Schermerhorn Alice C. , Shirlow Peter , Cummings E. Mark
Published: December 2010

Relatively little research has examined the relations between growing up in a community with a history of protracted violent political conflict and subsequent generations' well‐being. The current article examines relations between mothers' self‐report of the impact that the historical political violence in Northern Ireland (known as the Troubles) has on her and her child's current mental health. These relations are framed within the social identity model of stress, which provides a framework for understanding coping responses within societies that have experienced intergroup conflict. Mother‐child dyads (N=695) living in Belfast completed interviews. Results suggest that the mother‐reported impact of the Troubles continue to be associated with mothers' mental health, which, in turn, is associated with her child's adjustment. The strength of mothers' social identity moderated pathways between the impact of the Troubles and her mental health, consistent with the social identity model of stress. © 2010 Wiley Periodicals, Inc.
Social capital and community participation among migrant workers in China
Authors: Palmer Neal A. , Perkins Douglas D. , Xu Qingwen
Published: December 2010

In China, rapid development has prompted massive migration from rural to urban areas. Migrants' participation in Urban Residents Committees (URCs) and other community organizations offers opportunities for the development of social capital and democracy in contemporary China. We use 2006 survey data from a stratified convenience sample of 3,024 migrant workers in 7 Chinese cities to examine individual and community social capital and their relation to 3 types of community participation: (a) amount of contact with community organizations, (b) frequency of help sought from community organizations, and (c) the rate of participation in URC meetings. Multiple regressions yield, among 12 measures of individual and community‐focused social capital, only neighborhood interaction and organizational social capital as consistently and significantly associated for all 3 types of participation. Other measures were associated with certain types of participation, or were nonsignificant. Implications for migration policy, community participation, and social capital in China are discussed. © 2010 Wiley Periodicals, Inc.
Competing hypotheses analyses of the associations between group task conflict and group relationship conflict
Authors: Choi Kyoosang , Cho Bongsoon
Published: December 2010

Although previous research have reported strong and positive intercorrelations between group task conflict and group relationship conflict, several different theoretical rationales exist for the positive link and the empirical literature remains equivocal. To clarify the causal linkage between the two types of conflict, we derived seven models specifying how group task and relationship conflict can be related to each other, including some rival explanations. We tested the competing models using a longitudinal panel design, with data collected from 74 project teams comprising a total of 388 students. The results indicated that relationship conflict led to an increased subsequent task conflict through negative group affect. Task conflict, however, predicted a subsequent relationship conflict under a specific context, that is, groups that had lower levels of trust among the members. Copyright © 2010 John Wiley & Sons, Ltd.
Proteome profile of zebrafish caudal fin based on one‐dimensional gel electrophoresis LCMS/MS and two‐dimensional gel electrophoresis MALDI MS/MS analysis
Authors: Singh Sachin K. , Meena Lakshmi Mula G. , Saxena Sandeep , Swamy Cherukuvada V. Brahmendra , Idris Mohammed M.
Published: December 2010

Zebrafish (Danio rerio) is the widely used vertebrate model animal for understanding the complexity of development and disease process. Zebrafish has been also extensively used in understanding the mechanism of regeneration for its extensive capability of regenerating fins and other tissues. We have analyzed the proteome profile of zebrafish caudal fin in its native state based on one‐dimensional gel electrophoresis LCMS/MS and two‐dimensional gel electrophoresis MS/MS analyses. A total of 417 proteins were identified as zebrafish fin tissue specific, which includes 397 proteins identified based on one‐dimensional gel electrophoresis LCMS/MS analysis and 101 proteins identified based on two‐dimensional gel electrophoresis MALDI MS/MS. The proteins mapped to the zebrafish fin tissue were shown to be involved in various biological activities related to development, apoptosis, signaling and metabolic process. Focal adhesion, regulation of actin cytoskeleton, cancer‐related pathways, mitogen‐activated protein kinase signaling, antigen processing and presentation, and proteasome are some of the important pathways associated with the identified proteome data set of the zebrafish fin.
Reconstruction of the second metacarpal bone with a free vascularized scapular bone flap combined with nonvascularized free osteocartilagineous grafts from both second toes: A case report
Authors: Jaminet Patrick , Pfau Matthias , Greulich Michael
Published: November 2010

In this report, we present a case of a giant cell tumor of the second metacarpal bone. The tumor was treated by en bloc resection of the distal portion of the second metacarpal with adjacent interosseus muscle. Reconstruction was achieved using a free vascularized scapular bone flap with nonvascularized free osteocartilagineous grafts from both second toes. Structural integrity and metacarpophalangeal joint motion were preserved with good functional result. A brief review of literature is presented. © 2010 Wiley‐Liss, Inc. Microsurgery, 2011.
Validation of VASO cerebral blood volume measurement with positron emission tomography
Authors: Uh Jinsoo , Lin Ai‐Ling , Lee Kihak , Liu Peiying , Fox Peter , Lu Hanzhang
Published: December 2010

Cerebral blood volume (CBV) has been shown to be an important biomarker in a number of neurological disorders and in the quantitative interpretation of functional MRI. One approach to determine CBV in humans is vascular‐space‐occupancy MRI, and this technique has been applied to the studies of brain glioma, Schizophrenia, and Alzheimer's disease. However, validation of this technique with a gold standard method has not been reported. In this study, we compared vascular‐space‐occupancy MRI with a radiotracer‐based positron emission tomography technique in a group of healthy subjects. It was found that regional CBV measured with vascular‐space‐occupancy MRI was highly correlated with that of the positron emission tomography data (R = 0.79 ± 0.10, N = 8). Furthermore, absolute CBV values quantified by vascular‐space‐occupancy were also in excellent agreement with those by positron emission tomography (slope = 1.00 ± 0.15). Because of the differences in the labeling principles between the two modalities, systematic CBV differences were observed in large vessel and ventricle regions. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Zwei parallele Karrierewelten
Authors: Junk Christiane
Published: December 2010

Die Durchlässigkeit zwischen Akademia und Industrie ist gering. Was sind die Ursachen?
Discussing the definition of the second‐order work for unsaturated soils
Authors: Buscarnera Giuseppe , Prisco Claudio di
Published: December 2010

The volumetric compaction due to wetting processes is a phenomenon observed quite often in unsaturated soils. Under certain circumstances, saturation events can result into a sudden and unexpected collapse of the system. These phenomena are usually referred to as wetting‐induced collapses, without providing any detailed theoretical justification for this terminology. In order to predict in a general fashion the occurrence of coupled instabilities induced by saturation processes, a generalization of the theoretical approaches usually employed for saturated geomaterials is here provided. More specifically, this paper addresses the problem of hydro‐mechanical instability in unsaturated soils from an energy standpoint. For this purpose, an extension of the definition of the second‐order work is here suggested for the case of unsaturated porous media. On the basis of some examples of numerical simulations of laboratory tests, coupled hydro‐mechanical instabilities are then interpreted in the light of this second‐order energy measure. Finally, the implications of the theoretical results here presented are commented from a constitutive modelling perspective. Two possible alternative approaches to formulate incremental coupled constitutive relations are indeed discussed, showing how the onset of hydro‐mechanical instabilities can be predicted using an extended form of Hill's stability criterion. Copyright © 2010 John Wiley & Sons, Ltd.
Cytotoxicity, drug combinability, and biological correlates of ABT‐737 against acute lymphoblastic leukemia cells with MLL rearrangement
Authors: Jayanthan Aarthi , Incoronato Andrea , Singh Anjali , Blackmore Christopher , Bernoux Delphine , Lewis Victor , Stam Ronald , Whitlock James. A. , Narendran Aru
Published: November 2010

Background

ABT‐737 is a BH3 mimetic small‐molecule inhibitor that binds with high affinity to Bcl‐2 to induce apoptosis in malignant cells and has shown promise as an effective anti‐leukemic agent in pediatric preclinical tests. This study focuses on the effects of ABT‐737 on leukemia cells with MLL rearrangement and identifies some of the biological correlates of its activity.

Procedure

Cells were cultured in the presence of increasing concentrations of ABT‐737 alone or in combination with other agents. After 4 days in culture, cell growth inhibition was measured by Alamar blue assay. The expression and activation of potential intracellular targets of ABT‐737 activity were determined by Western blot analysis.

Results

Significant Bcl‐2 expression was detected in all infant leukemia cells investigated. ABT‐737 induced cell death in all cell lines studied although the IC50 values differed somewhat between cell lines. Western blot analysis identified the effects of ABT‐737 on survival and apoptosis‐regulatory proteins PARP, caspase‐8, and cytochrome‐c. Drug combination studies indicated synergy with distinct anti‐neoplastic agents, including the multi‐tyrosine kinase inhibitor sunitinib. This effective drug synergy appears to be mediated by the combined inhibition of Bcl‐2 and intracellular signaling pathways.

Conclusions

We describe the in vitro studies to demonstrate the activity and drug combinability of ABT‐737 against MLL rearranged leukemia cells. In addition, identification of the molecular changes that occur in the presence of ABT‐737 provides information regarding effective target validation and target modulation analyses in future clinical trials. Pediatr Blood Cancer 2011;56:353–360. © 2010 Wiley‐Liss, Inc.
Neurocognitive deficits in children with sickle cell disease are associated with the severity of anemia
Authors: Hijmans Channa T. , Grootenhuis Martha A. , Oosterlaan Jaap , Heijboer Harriët , Peters Marjolein , Fijnvandraat Karin
Published: December 2010

Background

Although neurocognitive deficits in children with sickle cell disease (SCD) have been well documented, the etiology of these deficits has not been completely clarified. The aim of this study was to investigate the association of laboratory markers of disease severity and radiological parameters with neurocognitive functioning in children with SCD.

Design and Methods

Participants were 37 children with SCD ((HbSS or HbS‐β0‐thalassemia) aged 6–18 years. All participants underwent extensive neurocognitive assessment. Further data (TCD values, laboratory test results, and MRI data) were obtained from medical charts. Associations were analyzed by hierarchical regression analysis.

Results

Hemoglobin was associated with a decrease in verbal short‐term memory. There was no association between TCD velocities and neurocognitive functioning, when controlled for age. Children with silent infarcts did not differ from children with normal MRI in neurocognitive functioning. Children with right–left asymmetries in cerebral blood flow as measured by continuous arterial spin labelling (CASL) MRI had better sustained attention than children without asymmetries.

Conclusions

Neurocognitive deficits are associated with the severity of anemia, indicating reduced oxygen delivery to the brain as an etiological mechanism. This implies that children with SCD and normal MRIs may still suffer from neurocognitive impairments, possibly affecting their academic development and full participation in society. Pediatr Blood Cancer 2011; 57: 297–302. © 2010 Wiley‐Liss, Inc.
Critical review of controversial issues in the management of advanced pediatric liver tumors
Authors: Gupta Abha A. , Gerstle J. Ted , Ng Vicky , Wong Ansely , Fecteau Annie , Malogolowkin Marcio H. , Meyers Rebecka L. , Grant David , Grant Ronald M.
Published: December 2010

Hepatocellular carcinoma (HCC) and hepatoblastoma (HB) are the most common primary tumors of liver in children. The management of patients with locally advanced, unresectable disease or those with extra‐hepatic distant metastases provides substantial challenges to pediatric oncologists, hepatologists, and surgeons. Herein, we critically debate the two sides of three specific controversies: (1) the role of chemotherapy in the treatment of advanced pediatric HCC; (2) the indications for liver transplantation in children with HCC, specifically, the appropriateness of using adult Milan criteria; and (3) the role of liver trasplantation in children with unresectable HB that present with metastatic disease. Pediatr Blood Cancer 2011;56:1013–1018. © 2010 Wiley‐Liss, Inc.
Acute chest syndrome is associated with history of asthma in hemoglobin SC disease
Authors: Poulter Elana Y. , Truszkowski Piotr , Thompson Alexis A. , Liem Robert I.
Published: November 2010

Background

Acute chest syndrome (ACS) is a frequent cause of morbidity and leading cause of death among individuals with sickle cell disease. Yet, ACS in hemoglobin SC disease is not well characterized. The objective of this study was to compare the presentation and clinical course of ACS in individuals with hemoglobin SC disease to that observed in individuals with hemoglobin SS disease.

Procedure

We retrospectively reviewed 71 inpatient episodes of ACS in patients with hemoglobin SC disease over a 20‐year period. Continuous and categorical data from index cases were compared with that from 71 control cases of ACS in patients with hemoglobin SS disease.

Results

Median length of hospitalization was shorter for hemoglobin SC episodes when compared to hemoglobin SS episodes (3.0 vs. 5.0 days, P < 0.001). In comparison to hemoglobin SS patients, a greater proportion of hemoglobin SC patients had a previous history of asthma or wheezing (50.7 vs. 33.8%, OR = 2.01 [1.02–3.96], P = 0.041) and a respiratory complaint of wheeze (11.3 vs. 2.8%, OR = 4.38 [0.90–21.4], P = 0.049). In our multivariate regression model, time to ACS diagnosis and total number of days of oxygen supplementation were independent predictors of length of hospitalization in both hemoglobin SC and SS episodes of ACS.

Conclusions

ACS appears to be less severe in children with hemoglobin SC disease compared to that in children with SS disease. Asthma and wheezing may represent more significant risk factors for the development of ACS in children with hemoglobin SC disease. Pediatr Blood Cancer 2011; 57: 289–293. © 2010 Wiley‐Liss, Inc.
Treatment of children with B‐cell non‐Hodgkin lymphoma in a low‐income country
Authors: Moleti Maria Luisa , Al‐Hadad Salma Abbas , Al‐Jadiry Mazin Faisal , Al‐Darraji Amir Fadhil , Al‐Saeed Raghad Majid , De Vellis Annalisa , Piciocchi Alfonso , Uccini Stefania , Foà Robin , Testi Anna Maria
Published: December 2010

Background

An adapted LMB 96 derived protocol for B‐cell non‐Hodgkin lymphoma (NHL) was implemented at the pediatric oncology unit of the Children Welfare Teaching Hospital in Baghdad (Iraq) from 2000 to present. The purpose was to evaluate the feasibility and efficacy of this intensive therapeutic regimen in a limited resource country.

Methods

Patients <15 years of age with high grade B‐cell NHL were included. A modified LMB 96 regimen was employed with a reduction of cyclophosphamide and methotrexate dosages due to inadequate laboratory facilities and supportive care.

Results

Between 2000 and 2005, 261 children with non‐lymphoblastic NHL were registered; 239 were eligible for the analysis. Two patients had stage I disease, 20 stage II, 179 stage III, and 38 stage IV. Fifty‐two patients (22%) had bulky disease. Twelve children were assigned to therapeutic group A (low risk), 184 to group B (intermediate risk), and 43 to group C (high risk). One hundred and eighty‐four patients (77%) had a complete response after the COP pre‐phase. Sixty‐nine patients (29%) died during treatment. Twenty‐nine patients abandoned treatment. At 24 months, the overall survival rate of the entire patient population was 66% (CI 95%: 62.2–70.6) and the event‐free survival rate 53.3% (CI 95%: 50.0–56.8).

Conclusions

The treatment schedule proved effective, but the treatment‐related mortality due to infections and metabolic complications was very high owing to the limited supportive care available. The high rate of treatment abandonment was also an important cause of failure, especially for children living far away from the hospital. Pediatr Blood Cancer 2011;56:560–567. © 2010 Wiley‐Liss, Inc.
Stereochemical control in the structures of linear δ,α‐hybrid tripeptides containing tetrahydrofuran amino acids
Authors: Chakraborty Tushar Kanti , Kumar N. V. Suresh , Roy Saumya , Dutta Samit Kumar , Kunwar Ajit Chand , Sridhar Balasubramanian , Singh Harjinder
Published: December 2010

Structural and electronic properties of diastereomers of tetrahydrofuran amino acids (TAA) derived tripeptide, Boc‐TAA‐Leu‐Val‐OMe, are studied using density functional theory. Predicted secondary folding patterns with hydrogen bonded pseudocycles of different sizes in peptides containing (2R,5S)‐cis‐TAA and (2S,5R)‐cis‐TAA are confirmed by detailed NMR studies of both, and single crystal X‐ray analysis of the former. A novel unusual folding pattern emanating from three‐centered hydrogen bond is found in peptide with (2R,5S)‐cis relationship. Stereochemical control on the orientation of interacting sites is substantiated by structural analysis of the peptides. Using natural bonding orbital and atoms in molecules analyses, charge transfer interactions are analyzed. Copyright © 2010 John Wiley & Sons, Ltd.
Degradable multisegmented polymers synthesized by consecutive radical addition‐coupling reaction of α,ω‐macrobiradicals and nitroso compound
Authors: Zhang Chengyu , Wang Qi
Published: December 2010

A consecutive radical addition‐coupling reaction induced by spin‐trapping agent is applied to produce degradable multisegmented polymer using α,ω‐dibromo polymer as a precursor. The macroradical generated by single electron transfer process catalyzed by Cu/PMDETA from α,ω‐dibromo polymer can be efficiently captured by 2‐methyl‐2‐nitrosopropane (MNP), which results in nitroxide radical. The in situ formed nitroxide radical immediately undergoes cross‐coupling reaction with polymeric radical, generating block polymer bridged with alkoxyamine moiety. The consecutive radical addition‐coupling reaction generates multisegmented polymer via step‐growth mechanism. Different multisegmented polymers have been prepared from α,ω‐dibromo‐PS, PtBA, and PtBA‐PS‐PtBA. The block number of multisegmented polymers can be tailored by varying the feed ratio of α,ω‐dibromo precursor to MNP. The multisegmented polymer can be degraded in the presence of hydrogen atom donor or air, and the molecular weight distribution transformed back into shape of its original precursor as it is conjugated by alkoxyamine moieties. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Kinetic analyses of disulfide formation between thiol groups attached to linear poly(acrylamide)
Authors: Hisano Nobuharu , Iwata Hiroo , Teramura Yuji , Chen Hao , Ikada Yoshito
Published: December 2010

Kinetic analyses were carried out for formation of disulfide crosslinkages between thiol groups on linear polymers, poly(acrylamide‐co‐N‐acrylcysteamine) (P‐SH). Disulfide crosslinkages were formed by auto‐oxidation of pendant thiol groups or through the thiol‐disulfide exchange reaction induced by addition of disulfide compounds gluthathione. In the auto‐oxidation reaction, the rate constant for disulfide formation highly depended on pH values of the reaction mixtures and the P‐SH concentrations. Gelation rate is too slow to enclose living cells into hydrogel under physiological pH 7.4. The hydrogel formation rate can be accelerated by addition of disulfides, such as oxidized glutathione. In the later case, oxygen in the reaction mixture is not consumed. The thiol‐disulfide exchange reaction is much more suitable for the cell encapsulation than the thiol auto‐oxidation reaction. These findings give a basis for enclosure of living cells in a hydrogel. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Crystal structure and substrate‐binding mode of cellulase 12A from Thermotoga maritima
Authors: Cheng Ya‐Shan , Ko Tzu‐Ping , Wu Tzu‐Hui , Ma Yanhe , Huang Chun‐Hsiang , Lai Hui‐Lin , Wang Andrew H.‐J. , Liu Je‐Ruei , Guo Rey‐Ting
Published: December 2010

Cellulases have been used in many applications to treat various carbohydrate‐containing materials. Thermotoga maritima cellulase 12A (TmCel12A) belongs to the GH12 family of glycoside hydrolases. It is a β‐1,4‐endoglucanase that degrades cellulose molecules into smaller fragments, facilitating further utilization of the carbohydrate. Because of its hyperthermophilic nature, the enzyme is especially suitable for industrial applications. Here the crystal structure of TmCel12A was determined by using an active‐site mutant E134C and its mercury‐containing derivatives. It adopts a β‐jellyroll protein fold typical of the GH12‐family enzymes, with two curved β‐sheets A and B and a central active‐site cleft. Structural comparison with other GH12 enzymes shows significant differences, as found in two longer and highly twisted β‐strands B8 and B9 and several loops. A unique Loop A3‐B3 that contains Arg60 and Tyr61 stabilizes the substrate by hydrogen bonding and stacking, as observed in the complex crystals with cellotetraose and cellobiose. The high‐resolution structures allow clear elucidation of the network of interactions between the enzyme and its substrate. The sugar residues bound to the enzyme appear to be more ordered in the −2 and −1 subsites than in the +1, +2 and −3 subsites. In the E134C crystals the bound −1 sugar at the cleavage site consistently show the α‐anomeric configuration, implicating an intermediate‐like structure. Proteins 2011; © 2011 Wiley‐Liss, Inc.
Stain etching of silicon with V2O5
Authors: Kolasinski Kurt W. , Yadlovskiy Julia
Published: December 2010

Formation of porous silicon by etching of silicon with vanadium pentoxide dissolved in HF(aq) has been studied with infrared spectroscopy and electron microscopy. The rate of film growth depends strongly on the V2O5 concentration. Addition of ethanol greatly decreases the etch rate and changes the pore morphology from a mixture of {100} + {110} planes to predominantly {100} planes. A plot of thickness vs. etch time in aqueous solutions evolves from a quadratic to a linear dependence. A model is developed in which the surface area depends linearly on film thickness and the thickness exhibits the measured functional form with respect to time. In this model pores with a uniform diameter nucleate randomly, initially grow rapidly before slowing to grow at a constant rate. The pore density increases linearly with time then saturates causing the transition to the linear growth rate phase. This model simultaneously fits both the short time and long time behaviour of the thickness and surface area. Pore formation does not involve an oxide intermediate. Films emit brilliant visible photoluminescence, and are highly uniform both in structure and photoluminescence. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Porous silicon‐based microtexturing of textured monocrystalline silicon solar cells
Authors: Saadoun Moncef , Fethi Boujmil Mohamed , Aouida Selma , Ben Rabha Mohamed , Bessaïs Brahim
Published: December 2010

This work aims to examine the effects of surface micro‐texturing on the performances of pyramidal textured monocrystalline silicon (c‐Si) photovoltaic solar cells. The surface micro‐textures were performed on the emitter of alkaline‐textured PV solar cells without damaging the junction, using the HNO3/HF vapor etching (VE) method. Scanning Electron Microscopy (SEM) shows that vapour etched pyramidal textures exhibit a high texture density essentially composed of porous silicon (PS) microstructure. The VE technique notably decreases the surface reflectivity from 12% for alkaline‐textured c‐Si wafers to about 6% after micro‐texturing. Subsequent to VE, the sheet resistance was found to increase indicating a reduction of the dead layer. Fourier Transform Infrared Spectroscopy (FTIR) measurements showed that the PS‐based micro‐textures are hydrogen‐rich, which could have passivation capabilities of the emitter. Taking into account basic phenomena occurring during carrier photogeneration and minority carrier collection, we tried explaining the variation of the short circuit current density (Jsc), the open circuit voltage (Voc) and the Fill factor (FF) due to PS‐microtexturing of the emitter of c‐Si solar cells (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Porous II‐VI vs. porous III‐V semiconductors
Authors: Langa S. , Tiginyanu I. M. , Monaico E. , Föll H.
Published: December 2010

In this work a morphological comparison of porous structures obtained by means of electrochemical etching in II‐VI (ZnSe, CdSe) and III‐V (InP, GaAs, GaP) semiconductors is presented. It is shown that in III‐V semiconductors current‐line and crystallographically oriented pores can be grown, whereas in II‐VI semiconductors only current line oriented pores can form. The lack of crystallographically oriented pores in II‐VI is a possible reason why no long range order for the current line oriented pores was observed in these materials up to now. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Antimony doped tin oxide nanoparticles and their assembly in mesostructured film
Authors: Müller Vesna , Rasp Matthias , Stefanic Goran , Günther Sebastian , Rathousky Jiri , Niederberger Markus , Fattakhova‐Rohlfing Dina
Published: December 2010

Mesoporous transparent conducting films of antimony‐doped tin oxide (ATO) were prepared by self‐assembly of crystalline ATO nanoparticles, which enables to obtain a fully crystalline frameworks with a sufficient electric conductivity. Such frameworks are promising as transparent electrodes with a high surface area, as shown for ferrocene molecules covalently immobilized within a conducting mesoporous matrix. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chemical resistance of porous silicon: photolithographic applications
Authors: Lai Meifang , Parish Gia , Dell John , Liu Yinong , Keating Adrian
Published: December 2010

Low‐temperature passivation is employed in this study to improve the chemical resistance of porous silicon to both weak‐alkali and HF solutions, enabling complex and multi‐mask patterning of porous silicon. Passivation is achieved by annealing the film in N2 atmosphere at temperatures ranging from 560°C‐800°C. The resistance of the passivated porous silicon to both KOH and HF solutions was examined by immersing the sample into these solutions and working out the optical thickness change. It is shown that higher passivation temperatures result in improved chemical resistance. Infrared spectroscopy show that exposing the films to HF can remove the passivation layer, enabling repeated anodisation; the restoration of the hydrogen bond on the porous silicon surface after HF immersion makes repeated passivation and processing possible (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Porous silicon used as an oxide diffusion mask to produce a periodic micro doped n++/n regions
Authors: Dimassi Wissem , Jafel Hayet , Lajnef Mohamed , Ali Kanzari M. , Bouaïcha Mongi , Bessaïs Brahim , Ezzaouia Hatem
Published: December 2010

The realization of screen‐printed contacts on silicon solar cells requires highly doped regions under the fingers and lowly doped and thin ones between them. In this work, we present a low‐cost approach to fabricate selective emitter (n++/n doped silicon regions), using oxidized porous silicon (ox‐PS) as a mask. Micro‐periodic fingers were opened on the porous silicon layer using a micro groove machining process. Optimized phosphorous diffusion through the micro grooved ox‐PS let us obtain n++ doped regions in opened zones and n doped large regions underneath the ox‐PS layer. The dark I‐V characteristics of the obtained device and Fourier transform infrared (FTIR) spectroscopy investigations of the PS layer show the possibility to use PS as a dielectric layer. The Light Beam Induced Current (LBIC) mapping of the realized device, confirm the presence of a micro periodic n++/n type structure. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of CdCl2 annealing treatment on CdS thin films and CdTe/CdS thin film solar cells
Authors: Bai Zhizhong , Wan Lei , Hou Zerong , Wang Deliang
Published: December 2010

In order to study the effect of CdCl2 annealing treatment on thin CdS films and CdTe/CdS thin film solar cells, a comparative study was carried out on three types of CdTe/CdS solar cells, which had different kinds of CdS window layer: as‐deposited CdS, air‐annealed CdS without CdCl2 pre‐coating, and CdCl2‐annealed CdS. When annealed in air the CdS film was partially oxidated to CdO and CdSO4. These oxides increased the series resistance of the CdTe solar cell and led to the lowest fill factor. The presence of CdCl2 on the surface of a CdS thin film during heat treatment in air protected it from oxidation and promoted the recrystallization of the CdS film, resulting in large and closely packed grains with a grain size of ∼ 50 ‐150 nm. CdTe/CdS solar cell with such a kind of CdS window layer showed the largest short circuit current and highest conversion efficiency of 12.4%. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characteristic of (Pb1‐xZnx)S tandem structured quantum dot‐sensitized solar cell having wide light absorbance
Authors: Shin Inyoung , Seo Hyunwoong , Son Min‐Kyu , Kim Jin‐Kyoung , Kim Heeje
Published: December 2010

A quantum dot‐sensitized solar cell (QD‐SSC) is one of these new type solar cells because of their advantages such as the inverse Auger effect, the tuning the particle size. Many quantum dot semiconductors such as CdS, CdSe, PbS and PbSe are used as the sensitizers instead of the ruthenium dye molecules in the QD‐SSC. The light absorbance of the quantum dot materials is changed as the dipping cycle and the amount of the materials. Therefore, the light absorbance and the efficiency of the QD‐SSC can be increased by using these characteristics.

In this study, we tried to widen the light absorbance of the QD‐SSC by changing the doping amounts of Pb and Zn in the (Pb1‐xZnx)S material. Finally, we fabricated the (Pb1‐xZnx)S tandem structured QD‐SSC. When the tandem structure multilayer as the layer which contains less Zn amount is placed on the bottom and the layer which contains more Pb amount is placed on the top side, the light absorbance is broaden effectively by using this tandem structure. As a result, we got the I‐V characteristics of (Pb1‐xZnx)S QD‐SSC with 3 multilayer, 0.38 V, 3.219 mA/cm2, 0.39 of FF, 0.48%. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Novel composite contact design and fabrication for planar Gunn devices for millimeter‐wave and terahertz frequencies
Authors: Khalid A. , Li C. , Pilgrim N. J. , Holland M. C. , Dunn G. M. , Cumming D. R. S.
Published: December 2010

Contacts to planar Gunn devices on the semiconductor surface suffer from high electric field stress and current crowding leading to premature burn out. We have developed a new composite contact design using a Schottky extension of the conventional Ohmic contact. The composite contact structures have been fabricated and tested to mitigate the effects of high concentrations of charge and high electric fields at the anode edge of the planar Gunn diode. Monte Carlo simulations confirm these experimental results in composite contacts. These results suggest a mechanism of increased lifetime when using composite contacts as compared to conventional Ohmic contacts. This is of significant importance for planar Gunn device operation at millimetre wave and terahertz frequencies where high doping density (∼1017cm‐ 3) and short cathode to anode separation (1µm or less) is required. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
HVPE growth of c‐plane AlN on a‐plane sapphire using nitridation layer
Authors: Takagi Yuta , Miyagawa Reina , Miyake Hideto , Hiramatsu Kazumasa
Published: December 2010

c‐plane AlN was grown on a‐ and c‐plane sapphire substrates by low‐pressure hydride vapor phase epitaxy with nitridation layer. The a‐plane sapphire was confirmed to be effective for obtaining high‐quality AlN with RMS surface roughness of 0.19 nm for 2 x 2 μm2 image and a large crack‐free thickness of 3.0 μm. The full widths at half maximum of (0002) and (10‐10) ω scans were 311 and 632 arcsec. for AlN on a‐plane sapphire substrate, respectively (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Surface plasmons for improving the performance of quantum dot structures for third generation solar cell applications
Authors: Pillai Supriya , Perez‐Wurfl Ivan , Conibeer Gavin J. , Green Martin A.
Published: December 2010

We use room temperature photoluminescence (PL) measurements to investigate the effect of surface plasmons on the emission from a single layer quantum dot structure. Silver metal nanoparticles are fabricated using self assembly techniques and tailored to provide selective scattering by varying the size of the particles. We report an 8 fold increase in the PL intensity at the peak emission wavelength of the silicon nanocrystals and up to a 15 fold increase in the emission corresponding to the surface plasmon resonance frequency. We attribute this enhnacement to both the scattering in and outcoupling of light by excitation of surface plasmons. The energy transfer from the nanocrystal excitons to surface plasmons and vice versa is tunable and has the potential to increase absorption in the bandgap engineered quantum dot cells for third generation photovoltaic (PV) applications such as tandem solar cells and hot‐carrier cells. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoinduced dynamics of the multi‐orbital Hubbard model
Authors: Maeshima Nobuya , Hino Ken‐ichi , Yonemitsu Kenji
Published: December 2010

We investigate photoinduced dynamical properties of the one‐dimensional two‐orbital degenerate Hubbard model by calculating the time‐dependent many‐electron wave function. The transient optical response spectra around the charge‐transferpeak show characteristic coherent oscillations, which can be attributed to the Raman‐active orbital excitations (orbitons). An analysis for the oscillating component shows that the photoinduced oscillations are caused by the quantum interference between photogenerated states. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Excitation power dependence of nonlinear optical response of excitons in GaAs/AlAs superlattices
Authors: Yamashita Takae , Kojima Osamu , Kita Takashi , Akahane Kouichi
Published: December 2010

We studied effects of the miniband structure to control the nonlinear optical response of excitons in GaAs/AlAs superlattices. The excitation‐power dependence of the degenerate four‐wave‐mixing signal shows different saturation power in the samples with the thinner and thicker barriers, while the dependence of dephasing time is almost independent of the barrier width. The analysis of the excitation‐power dependence of the photoluminescence spectrum indicates the biexciton generation at lower excitation power in the sample with the thicker barrier width. These results demonstrate that the saturation of the four‐wave‐mixing signal intensity of the exciton comes from the contribution of the biexcitons. Our results support a possibility that the nonlinear optical response of excitons can be controlled by controlling the barrier width. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ground state of electron‐hole bilayer with density imbalance
Authors: Yamashita Kazuo , Asano Kenichi , Ohashi Takuma
Published: December 2010

We study electron‐hole bilayer system with density imbalance at zero temperature. By means of the mean‐field theory, we derive phase diagram and find that the FuldeFerrell state exists in vast areas of high density regions.

We clarify that the system with long‐range interaction is fairly efficient for the realization of the Fulde‐Ferrell state due to the order parameter mixing effect. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photogenerated carriers in Si‐related random composites
Authors: Itoh Takashi
Published: December 2010

Behaviors of photogenerated carriers in Si‐related random composites, hydrogenated microcrystalline silicon (μc‐Si:H) and hydrogenated amorphous silicon (a‐Si:H) have been discussed. In μc‐Si:H film, the γ ‐value changes from 0.82 to around 1 with decreasing the temperature from 300 K to 180 K. In a‐Si:H film, the gradual increase in the γ ‐value due to the photo‐degradation. In a‐Si:H thin film solar cell, the γ‐value of 0.95 is obtained from the light intensity dependence of photoconductivity. The discussions have been focused on recombination processes through the γ ‐value in μc‐Si:H and a‐Si:H films, and also in a‐Si:H thin film solar cell. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High vertical breakdown strength in with low specific on‐resistance AlGaN/AlN/GaN HEMTs on silicon
Authors: Arulkumaran S. , Vicknesh S. , Ng G. I. , Liu Z. H. , Selvaraj S. L. , Egawa T.
Published: December 2010

Off‐state and vertical breakdown characteristics of AlGaN/AlN/GaN high‐electron‐mobility transistors (HEMTs) on high‐resistivity (HR)‐Si substrate were investigated and analysed. Three‐terminal off‐state breakdown (BVgd) was measured as a function of gate–drain spacing (Lgd). The saturation of BVgdwithLgdis because of increased gate leakage current. HEMTs withLgd= 6 µm exhibited a specific on‐resistanceRDS[ON]of 0.45 mΩ cm2. The figure of merit (FOM = BVgd2/RDS[ON]) is as high as 2.0 × 108V2Ω–1cm–2, the highest among the reported values for GaN HEMTs on Si substrate. A vertical breakdown of ∼1000 V was observed on 1.2 µm thick buffer GaN/AlN grown on Si substrate. The occurrence of high breakdown voltage is due to the high quality of GaN/AlN buffer layers on Si substrate with reduced threading dislocations which has been confirmed by transmission electron microscopy (TEM). This indicates that the AlGaN/AlN/GaN HEMT with 1.2 µm thick GaN/AlN buffer on Si substrate is promising candidate for high‐power and high‐speed switching device applications. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An evaluation of resampling methods for assessment of survival risk prediction in high‐dimensional settings
Authors: Subramanian Jyothi , Simon Richard
Published: December 2010

Resampling techniques are often used to provide an initial assessment of accuracy for prognostic prediction models developed using high‐dimensional genomic data with binary outcomes. Risk prediction is most important, however, in medical applications and frequently the outcome measure is a right‐censored time‐to‐event variable such as survival. Although several methods have been developed for survival risk prediction with high‐dimensional genomic data, there has been little evaluation of the use of resampling techniques for the assessment of such models. Using real and simulated datasets, we compared several resampling techniques for their ability to estimate the accuracy of risk prediction models. Our study showed that accuracy estimates for popular resampling methods, such as sample splitting and leave‐one‐out cross validation (Loo CV), have a higher mean square error than for other methods. Moreover, the large variability of the split‐sample and Loo CV may make the point estimates of accuracy obtained using these methods unreliable and hence should be interpreted carefully. Ak‐fold cross‐validation withk= 5 or 10 was seen to provide a good balance between bias and variability for a wide range of data settings and should be more widely adopted in practice. Published in 2010 by John Wiley & Sons, Ltd.
First Coordination Polymer of 1,4‐Dihydro‐2,3‐Quinoxalinedione in Ketoamine Tautomeric Form
Authors: Shi Ling , Cai Bin , Huang Guang , Wu Jian‐Zhong , Yu Ying
Published: December 2010

The first coordination compound of 1,4‐dihydro‐2,3‐quinoxalinedione in ketoamine tautomeric form (denoted as H2qdione) was reported. H2qdione was obtained by a solid‐state reaction of o‐phenylenediamine and oxalic acid. Reaction of this ligand with CdCl2 solvothermally yielded a coordination polymer [Cd(H2qdione)Cl2]n, which was structurally characterized by X‐ray diffraction and IR spectroscopy. Continuous Cd2Cl2 diamonds form a double‐sided comb with terminal H2qdione‐κ2O,O′ as the comb teeth. Interaction of these combs through very extensive π–π stacking, C–H···Cl, and N–H···Cl hydrogen bonds leads to a novel 3D architecture and significant enhancement of solid‐state luminescence of about 10 times compared to the free H2qdione ligand.
The past, present, and future of experimental software engineering
Authors: Basili Victor Robert
Published: December 2010

This paper gives a 40 year overview of the evolution of experimental software engineering, from the past to the future, from a personal perspective. My hypothesis is that my work followed the evolution of the field. I use my own experiences and thoughts as a barometer of how the field has changed and present some opinions about where we need to go.