bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequent Truncating Mutation of TFAM Induces Mitochondrial DNA Depletion and Apoptotic Resistance in Microsatellite-Unstable Colorectal Cancer
Authors: Guo Jianhui , Zheng Li , Liu Wenyong , Wang Xianshu , Wang Zemin , Wang Zehua , French Amy J. , Kang Dongchon , Chen Lin , Thibodeau Stephen N. , Liu Wanguo
Published: April 2011

The mitochondrial transcription factor A (TFAM) is required for mitochondrial DNA (mtDNA) replication and transcription. Disruption of TFAM results in heart failure and premature aging in mice. But very little is known about the role of TFAM in cancer development. Here, we report the identification of frequent frameshift mutations in the coding mononucleotide repeat of TFAM in sporadic colorectal cancer (CRC) cell lines and in primary tumors with microsatellite instability (MSI), but not in microsatellite stable (MSS) CRC cell lines and tumors. The presence of the TFAM truncating mutation, in CRC cells with MSI, reduced the TFAM protein level in vivo and in vitro and correlated with mtDNA depletion. Furthermore, forced overexpression of wild-type TFAM in RKO cells carrying a TFAM truncating mutation suppressed cell proliferation and inhibited RKO cell-induced xenograft tumor growth. Moreover, these cells showed more susceptibility to cisplatin-induced apoptosis due to an increase of cytochrome b (Cyt b) expression and its release from mitochondria. An interaction assay between TFAM and the heavy-strand promoter (HSP) of mitochondria revealed that mutant TFAM exhibited reduced binding to HSP, leading to reduction in Cyt b transcription. Collectively, these data provide evidence that a high incidence of TFAM truncating mutations leads to mitochondrial copy number reduction and mitochondrial instability, distinguishing most CRC with MSI from MSS CRC. These mutations may play an important role in tumorigenesis and cisplatin-induced apoptotic resistance of most microsatellite-unstable CRCs. Cancer Res; 71(8); 2978–87. ©2011 AACR.
Prognostic Significance of Truncating TP53 Mutations in Head and Neck Squamous Cell Carcinoma
Authors: Lindenbergh-van der Plas Marlon , Brakenhoff Ruud H. , Kuik Dirk J. , Buijze Marijke , Bloemena Elisabeth , Snijders Peter J.F. , Leemans C. René , Braakhuis Boudewijn J.M.
Published: April 2011

Purpose: TP53 is a key gene in cellular homeostasis and is frequently mutated in head and neck squamous cell carcinoma (HNSCC). There is a variety of TP53 mutations, each with its own biological and clinical implication. Aim of the study was to assess the prognostic significance of TP53 mutations in HNSCCs and to identify the most relevant mutation.

Experimental Design: TP53 mutation status was investigated in 141 consecutive HNSCCs treated by surgery with radiotherapy when indicated and with a known human papilloma virus status. The type of mutation was correlated with overall and progression-free survival in a multivariate two-sided Cox regression analysis with wild type as reference.

Results: A TP53 mutation was found in 88 (62.4%) of the carcinomas and was not significantly associated with overall survival (HR = 1.65, P = 0.11). Patients with a mutation resulting in a truncated protein (n = 36, 25.5%) had a significantly worse overall survival (HR = 2.54, P = 0.008) and progression-free survival (HR = 2.65, P = 0.002). Four of these mutations were at a splice site, 13 were nonsense mutations (produces stop codon), and 19 were insertions or deletions resulting in a frameshift. After multivariate analysis, a truncating mutation remained a significant prognosticator. A missense (i.e., nontruncating) mutation did not influence prognosis. Other ways of classification (disruptive vs. nondisruptive, hotspot vs. nonhotspot, and DNA binding vs. non–DNA binding) were less discriminative.

Conclusion: In HNSCCs, a truncating TP53 mutation is associated with a poor prognosis. This patient group seems as a target population for adjuvant therapy with chemoradiation or viral vector–mediated TP53 gene transfer. Clin Cancer Res; 17(11); 3733–41. ©2011 AACR.
Genome-Wide DNA Methylation Profiles in Renal Tumors of Various Histological Subtypes and Non-Tumorous Renal Tissues
Authors: Arai Eri , Wakai-Ushijima Saori , Fujimoto Hiroyuki , Hosoda Fumie , Shibata Tatsuhiro , Kondo Tadashi , Yokoi Sana , Imoto Issei , Inazawa Johji , Hirohashi Setsuo , Kanai Yae
Published: April 2011

Objective: The aim of this study is to clarify genome-wide DNA methylation profiles in renal tumors of various histological subtypes. Methods: Bacterial artificial chromosome (BAC) array-based methylated CpG island amplification was performed using tissue samples of 17 patients with papillary renal cell carcinomas (RCCs), chromophobe RCCs and oncocytomas, and the results were compared with those from 51 patients with clear cell RCCs. Results: Unsupervised hierarchical clustering analysis based on DNA methylation status clustered type 1 and type 2 papillary RCCs into different subclasses. Although chromophobe RCCs and oncocytomas were clustered into the same subclass, the DNA methylation status of 21 BAC clones was able to discriminate chromophobe RCCs from oncocytomas. The number of BAC clones showing DNA methylation alteration in non-tumorous renal tissue from patients with chromophobe RCCs and oncocytomas was smaller than that from patients with clear cell RCCs. Biphasic accumulation of DNA methylation alterations was observed in non-tumorous renal tissue from all 68 patients, and patients showing such alterations on more BAC clones had a poorer outcome than patients showing them on fewer BAC clones. Conclusions: DNA methylation profiles determining the histological subtypes of renal tumors developing in individual patients and/or patient outcome may be already established in non-tumorous renal tissue at the precancerous stage.
Localization of the Invadopodia-Related Proteins Actinin-1 and Cortactin to Matrix-Contact-Side Cytoplasm of Cancer Cells in Surgically Resected Lung Adenocarcinomas
Authors: Hirooka Shinichi , Akashi Takumi , Ando Noboru , Suzuki Yoshimi , Ishida Noriko , Kurata Morito , Takizawa Touichirou , Kayamori Kou , Sakamoto Kei , Fujiwara Naoyuki , Kojima Masao , Eishi Yoshinobu
Published: April 2011

Objectives: Actin-associated proteins at cell-matrix-contact sites form invadopodia in cancer cells and participate in migration, matrix degradation and invasion. We investigated an alteration of subcellular localization of invadopodia-related actin-associated proteins, actinin-1 and cortactin, in lung adenocarcinomas, its clinical significance, and its possible regulatory factors. Methods: Invadopodia-related proteins, actinin-1 and cortactin, were immunohistochemically examined in 90 cases of lung adenocarcinomas. Expression of invadopodia-associated proteins and their possible regulators in lung adenocarcinomas were examined by real-time RT-PCR, database search, and immunohistochemistry. Results: Actinin-1 and cortactin showed matrix-contact-side localization in adenocarcinoma cells, but rarely in normal bronchiolar epithelial cells, alveolar cells, or precursor lesion atypical adenomatous hyperplasia cells. Immunoelectron-microscopic examination of adenocarcinoma cells revealed actinin-1 localization to matrix-contact-side cytoplasm with cytoplasmic protrusions. Matrix-contact-side localization of actinin-1 and cortactin was correlated with tumor stages, lymph node metastasis, vascular permeation, and loss of basement membrane. The tumor-specific survival rate was worse for the group in which matrix-contact-side localization of cortactin was high than for the low group. mRNA of the Rho guanine exchange factor epithelial cell transforming sequence-2 (Ect2) tended to be overexpressed in lung adenocarcinomas and cytoplasmic expression of Ect2 tended to be correlated with matrix-contact-side localization of actinin-1. Conclusion: Matrix-contact-side localization of invadopodia-related proteins in the lung adenocarcinoma cells were correlated with invasion, metastasis, and poor prognosis. Ect2 was a possible regulator of matrix-contact-side localization of invadopodia-related proteins.
Vascular Pericyte Density and Angiogenesis Associated with Adenocarcinoma of the Prostate
Authors: Killingsworth Murray C. , Wu Xiaojuan
Published: April 2011

Background/Aims: Angiogenesis facilitates metabolism, proliferation and metastasis of adenocarcinoma cells in the prostate, as without the development of new vasculature tumor growth cannot be sustained. However, angiogenesis is variable with the well-known phenomenon of vascular ‘hotspots’ seen associated with viable tumor cell mass. With the recent recognition of pericytes as molecular regulators of angiogenesis, we have examined the interaction of these cells in actively growing new vessels. Methods: Pericyte interactions with developing new vessels were examined using transmission electron microscopy. Pericyte distribution was mapped from α-SMA+ immunostained histological sections and quantified using image analysis. Data was obtained from peripheral and more central regions of 27 cases with Gleason scores of 4–9. Results: Pericyte numbers were increased around developing new vessel sprouts at sites of luminal maturation. Numbers were reduced around the actively growing tips of migrating endothelial cells and functional new vessels. Tumor regions internal to a 500-µm peripheral band showed higher microvessel pericyte density than the peripheral region. Conclusion: Pericytes were found to be key cellular components of developing new vessels in adenocarcinoma of the prostate. Their numbers increased at sites of luminal maturation with these cells displaying an activated phenotype different to quiescent pericytes. Increased pericyte density was found internal to the peripheral region, suggesting more mature vessels lie more centrally.
Non-Neoplastic TdT-Positive Cells in Bone Marrow Trephines with Acute Myeloid Leukaemia before and after Treatment Express Myeloid Molecules
Authors: Jöhrens Korinna , Franke Aylin , Dietel Manfred , Anagnostopoulos Ioannis
Published: April 2011

Objectives: Terminal deoxynucleotidyltransferase (TdT)-positive cells in non-neoplastic bone marrow are regarded as haematogones and show a characteristic morphology and immunophenotype. During our routine bone marrow trephine analysis of patients with acute myeloid leukaemia (AML) before and after treatment, we observed the presence of TdT-positive cells lacking CD34, CD10 and B cell antigens. Methods: To verify the nature of these TdT-positive cells, we analyzed 140 paraffin-embedded and decalcified trephines from 67 AML patients before and after therapy using double immunolabellings. Results: In 61% of the cases TdT-positive cells were present. After exclusion of neoplastic cells and haematogones, we identified that 16% of the cases harboured cells co-expressing myeloperoxidase and TdT, 15% glycophorin C and TdT, 13% CD117 and TdT and one case CD3 and TdT. These cells made up to 30% of the non-neoplastic TdT-positive cells. No differences in the number of TdT-positive cells before and after chemotherapy or stem cell transplantation could be observed. Conclusion: While the reason of TdT expression by non-neoplastic myeloid cells is unknown, their presence should be taken into account when evaluating such cases.
Characteristics and Outcomes of Very Elderly Patients After First Hospitalization for Heart Failure
Authors: Shah Rashmee U. , Tsai Vivian , Klein Liviu , Heidenreich Paul A.
Published: April 2011

Background—

The very elderly (age 80 years and older) with heart failure (HF) is a growing population that is rarely included in clinical trials. The aim of this investigation was to describe the characteristics and outcomes of very elderly patients after a first HF hospitalization.

Methods and Results—

We identified very elderly patients (age 80 years and older) discharged with HF from the Veteran's Administration National Patient Care Database from 1999 to 2008. Outcomes of interest were death during index admission, 30-day and 1-year mortality, and 30-day all-cause and HF readmissions. We used generalized estimating equations to evaluate outcome differences between age groups within the very elderly cohort (ages 80 to 84, 85 to 89, and 90 and older), adjusting for comorbidities, demographics, and clustering by treatment facility. We identified 21 397 very elderly veterans with a first HF hospitalization during the study period. Thirty-day mortality decreased from 14% to 7% (both
P
<0.001) and 1-year mortality decreased from 49% to 27% (
P
<0.001). Although these improvements were most notable for patients age 90 and older (1-year mortality improved by 25.9%), the adjusted odds of death within 1 year were highest for the oldest veterans (odds ratio, 1.85; 95% confidence interval, 1.64 to 2.09, using the 80- to 85-year age group as reference). For all patients, 30-day all-cause readmissions remained largely unchanged and did not differ between age groups.

Conclusions—

Mortality for very elderly HF patients has improved over time, but 30-day readmissions remain frequent. Future studies should identify interventions to reduce cardiac and noncardiac rehospitalization of very elderly HF patients.
Stationary Atmospheric Responses to an Idealized Sea Surface Temperature Anomaly in the Southern Ocean
Authors: Maze Guillaume , D’Andrea Fabio , Colin de Verdière Alain , Klein Patrice
Published: April 2011

The stationary atmospheric response to an idealized sea surface temperature anomaly (SSTA) is studied with a quasigeostrophic atmospheric model of the Southern Hemisphere. Sensitivity of the stationary response to the midlatitude SSTA location is determined and responses are decomposed on vertical modes.

The SSTA almost directly forces baroclinic responses, inducing warm-air anomalies 40°–50° downstream, eastward, to the SSTA. These baroclinic responses arise from an equilibrium between the SSTA-induced anomalous vortex stretching and (i) advection by the quasi-stationary flow and (ii) dissipation by high-frequency eddies.

The barotropic response consists of a midlatitude ridge (trough) and a South Pole trough (ridge) for SSTAs localized from the Drake Passage to the western Indian Ocean (from south of Australia to the center of the Pacific Ocean). This response can be further decomposed into (i) a zonally asymmetric component, a quasi-stationary wave train forced by a barotropic ridge downstream of the SSTA; and (ii) a zonal-mean component similar to a meridional shift of westerlies and hence a southern annular mode (SAM)-like pattern. The former component is phase locked with the SSTA position, while the latter has a phase that depends on the relative SSTA position with regard to the background quasi-stationary wave pattern. The study shows that the barotropic downstream ridge response is responsible for modifying the low-frequency eddy–mean flow interactions through relative vorticity fluxes and inducing the bipolar projection of the zonal-mean response.
miR-223 regulates migration and invasion by targeting Artemin in human esophageal carcinoma
Authors: Li Shujun , Li Zhigang , Guo Fengjie , Qin Xuebo , Liu Bin , Lei Zhe , Song Zuoqing , Sun Liya , Zhang Hong-Tao , You Jiacong , Zhou Qinghua
Published: April 2011

Background

Artemin (ARTN) is a neurotrophic factor belonging to the glial cell-derived neurotrophic factor family of ligands. To develop potential therapy targeting ARTN, we studied the roles of miR-223 in the migration and invasion of human esophageal carcinoma.

Methods

ARTN expression levels were detected in esophageal carcinoma cell lines KYSE-150, KYSE-510, EC-9706, TE13, esophageal cancer tissues and paired non-cancerous tissues by Western blot. Artemin siRNA expression vectors were constructed to knockdown of artemin expression mitigated migration and invasiveness in KYSE150 cells. Monolayer wound healing assay and Transwell invasion assay were applied to observe cancer cell migration and invasion. The relative levels of expression were quantified by real-time quantitative PCR.

Results

ARTN expression levels were higher in esophageal carcinoma tissue than in the adjacent tissue and was differentially expressed in various esophageal carcinoma cell lines. ARTN mRNA contains a binding site for miR-223 in the 3'UTR. Co-transfection of a mir-223 expression vector with pMIR-ARTN led to the reduced activity of luciferase in a dual-luciferase reporter gene assay, suggesting that ARTN is a target gene of miR-223. Overexpression of miR-223 decreased expression of ARTN in KYSE150 cells while silencing miR-223 increased expression of ARTN in EC9706 cells. Furthermore, overexpression of miR-223 in KYSE150 cells decreased cell migration and invasion. Silencing of miR-223 in EC9706 cells increased cell migration and invasiveness.

Conclusions

These results reveal that ARTN, a known tumor metastasis-related gene, is a direct target of miR-223 and that miR-223 may have a tumor suppressor function in esophageal carcinoma and could be used in anticancer therapies.
Fnr (EtrA) acts as a fine-tuning regulator of anaerobic metabolism in Shewanella oneidensisMR-1
Authors: Cruz-García Claribel , Murray Alison E , Rodrigues Jorge LM , Gralnick Jeffrey A , McCue Lee Ann , Romine Margaret F , Löffler Frank E , Tiedje James M
Published: April 2011

Background

EtrA in Shewanella oneidensis MR-1, a model organism for study of adaptation to varied redox niches, shares 73.6% and 50.8% amino acid sequence identity with the oxygen-sensing regulators Fnr in E. coli and Anr in Pseudomonas aeruginosa, respectively; however, its regulatory role of anaerobic metabolism in Shewanella spp. is complex and not well understood.

Results

The expression of the nap genes, nrfA, cymA and hcp was significantly reduced in etrA deletion mutant EtrA7-1; however, limited anaerobic growth and nitrate reduction occurred, suggesting that multiple regulators control nitrate reduction in this strain. Dimethyl sulfoxide (DMSO) and fumarate reductase gene expression was down-regulated at least 2-fold in the mutant, which, showed lower or no reduction of these electron acceptors when compared to the wild type, suggesting both respiratory pathways are under EtrA control. Transcript analysis further suggested a role of EtrA in prophage activation and down-regulation of genes implicated in aerobic metabolism.

Conclusion

In contrast to previous studies that attributed a minor regulatory role to EtrA in Shewanella spp., this study demonstrates that EtrA acts as a global transcriptional regulator and, in conjunction with other regulators, fine-tunes the expression of genes involved in anaerobic metabolism in S. oneidensis strain MR-1. Transcriptomic and sequence analyses of the genes differentially expressed showed that those mostly affected by the mutation belonged to the "Energy metabolism" category, while stress-related genes were indirectly regulated in the mutant possibly as a result of a secondary perturbation (e.g. oxidative stress, starvation). We also conclude based on sequence, physiological and expression analyses that this regulator is more appropriately termed Fnr and recommend this descriptor be used in future publications.
Prevalence of active HCV infection among the blood donors of Khyber Pakhtunkwa and FATA region of Pakistan and evaluation of the screening tests for anti-HCV
Authors: Khan Najib U , Ali Ijaz , Ahmad Naeem U , Iqbal Aqib , Rehman Latif U , Munir Iqbal , Rehman Muti U , Khan Sanaullah , Ali Sajid , Siddique Lubna , Swati Zahoor A
Published: April 2011

Hepatitis C is a fatal liver disease caused by the hepatitis C virus. In this study, blood donors, from various districts of the KPK province and the federally administered tribal area (FATA) of Pakistan were tested for anti-HCV antibodies and HCV RNA by ICT (Immuno-chromatographic test), ELISA and RT-PCR. Out of the 7148 blood donors, 224 (3.13%) were positive for anti-HCV antibodies by ICT, 135 (1.89%) by ELISA while 118 (1.65%) blood donors had active HCV infection as detected by RT-PCR. We suggest that ELISA should be used for anti-HCV screening in public sector hospitals and health care units.
Bridging the gap between basic science and clinical practice: The role of organizations in addressing clinician barriers
Authors: Beckett Megan , Quiter Elaine , Ryan Gery , Berrebi Claude , Taylor Stephanie , Cho Michelle , Pincus Harold , Kahn Katherine
Published: April 2011

Background

New National Institutes of Health policies call for expansion of practice-based research to improve the clinical research enterprise and facilitate dissemination of evidence-based medicine.

Objective

This paper describes organizational strategies that influence clinicians' decisions to participate in clinical research.

Design

We reviewed the literature and interviewed over 200 clinicians and stakeholders.

Results

The most common barriers to community clinician participation in clinical research relate to beliefs that clinical research is too burdensome and has little benefit for the participating clinician or patient. We identified a number of approaches healthcare organizations can use to encourage clinicians to participate in research, including an outreach campaign to promote the benefits of clinical research; selection of study topics of interest to clinicians; establishment and enforcement of a set of research principles valuing the clinician and patient; development of a transparent schedule of reimbursement for research tasks; provision of technological and technical assistance to practices as needed; and promotion of a sense of community among clinicians involved in practice-based research.

Conclusions

Many types of existing healthcare organizations could provide the technical and intellectual assistance community clinicians need to participate in clinical research. Multiple approaches are possible.
A giant adrenal lipoma presenting in a woman with chronic mild postprandial abdominal pain: a case report
Authors: Kapetanakis Stylianos , Drygiannakis Ioannis , Tzortzinis Anastasios , Papanas Nikolaos , Fiska Aliki
Published: April 2011

Introduction

Adrenal lipomas are rare, small, benign, non-functioning tumors, which must be histopathologically differentiated from other tumors such as myelolipomas or liposarcomas. They are usually identified incidentally during autopsy, imaging, or laparotomy. Occasionally, they may present acutely due to complications such as abdominal pain from retroperitoneal bleeding, or systemic symptoms of infection. We report a giant adrenal lipoma (to the best of our knowledge, the second largest in the literature) clinically presenting with chronic mild postprandial pain.

Case presentation

A 54-year-old Caucasian woman presented several times over a period of 10 years to various emergency departments complaining of long-term mild postprandial abdominal pain. Although clinical examinations were unrevealing, an abdominal computed tomography scan performed at her most recent presentation led to the identification of a large lipoma of the left adrenal gland, which occupied most of the retroperitoneal space. Myelolipoma was ruled out due to the absence of megakaryocytes, immature leukocytes, or erythrocytes. Liposarcoma was ruled out due to the absence of lipoblasts. The size of the lipoma (16 × 14 × 7 cm) is, to the best of our knowledge, the second largest reported to date. After surgical resection, our patient was relieved of her symptoms and remains healthy six years postoperatively.

Conclusion

Physicians should be aware that differential diagnosis of mild chronic abdominal pain in patients presenting in emergency rooms may include large adrenal lipomas. When initial diagnostic investigation is not revealing, out-patient specialist evaluation should be planned to enable appropriate further investigations.
Life expectancies and incidence rates of patients under prolonged mechanical ventilation: a population-based study during 1998 to 2007 in Taiwan
Authors: Hung Mei-Chuan , Lu Hsin-Ming , Chen Likwang , Hu Fu-Chang , Chan Soa-Yu , Yan Yuan-Horng , Fan Po-Sheng , Lin Ming-Shian , Chen Cheng-Ren , Kuo Lu-Cheng , Yu Chong-Jen , Wang Jung-Der
Published: April 2011

Introduction

The present study examined the median survival, life expectancies, and cumulative incidence rate (CIR) of patients undergoing prolonged mechanical ventilation (PMV) stratified by different underlying diseases.

Methods

According to the National Health Insurance Research Database of Taiwan, there were 8,906,406 individuals who obtained respiratory care during the period from 1997 to 2007. A random sample of this population was performed, and subjects who had continuously undergone mechanical ventilation for longer than 21 days were enrolled in the current study. Annual incidence rates and the CIR were calculated. After stratifying the patients according to their specific diagnoses, latent class analysis was performed to categorise PMV patients with multiple co-morbidities into several groups. The life expectancies of different groups were estimated using a semiparametric method with a hazard function based on the vital statistics of Taiwan.

Results

The analysis of 50,481 PMV patients revealed that incidence rates increased as patients grew older and that the CIR (17 to 85 years old) increased from 0.103 in 1998 to 0.183 in 2004 before stabilising thereafter. The life expectancies of PMV patients suffering from degenerative neurological diseases, stroke, or injuries tended to be longer than those with chronic renal failure or cancer. Patients with chronic obstructive pulmonary disease survived longer than did those co-morbid with other underlying diseases, especially septicaemia/shock.

Conclusions

PMV provides a direct means to treat respiratory tract diseases and to sustain respiration in individuals suffering from degenerative neurological diseases, and individuals with either of these types of conditions respond better to PMV than do those with other co-morbidities. Future research is required to determine the cost-effectiveness of this treatment paradigm.
The CRIT framework for identifying cross patterns in systems biology and application to chemogenomics
Authors: Gianoulis Tara A , Agarwal Ashish , Snyder Michael , Gerstein Mark B
Published: April 2011

Biological data is often tabular but finding statistically valid connections between entities in a sequence of tables can be problematic - for example, connecting particular entities in a drug property table to gene properties in a second table, using a third table associating genes with drugs. Here we present an approach (CRIT) to find connections such as these and show how it can be applied in a variety of genomic contexts including chemogenomics data.
Bayart's Broken Kettle
Authors: Young Robert J. C.
Published: April 2011

A critique of Jean-François Bayart's polemics against postcolonial studies, which, it is argued, works through unsubstantiated generalizations rather than detailed analysis of the key texts in the field.
Re-examining covariance risk dynamics in international stock markets using quantile regression analysis
Authors: Li M. , Yen S.
Published: April 2011

This investigation is one of the first to adopt quantile regression (QR) technique to examine covariance risk dynamics in international stock markets. Feasibility of the proposed model is demonstrated in G7 stock markets. Additionally, two conventional random-coefficient frameworks, including time-varying betas derived from GARCH models and state-varying betas implied by Markov-switching models, are employed and subjected to comparative analysis. The empirical findings of this work are consistent with the following notions. First, the beta smile (beta skew) curve for the Italian, U.S. and U.K. (Canadian, French and German) markets. That is, covariance risk among global stock markets in extremely bull and/or bear market states is significantly higher than in stable periods. Additionally, the Japanese market provides a special case, and its beta estimate at extremely bust state is significantly lower, not higher than that at the middle region. Second, the quantile-varying betas are identified as possessing two key advantages. Specifically, the comparison of the system with quantile-varying betas against that with time-varying betas implied by GARCH models provides meaningful implications for correlation-volatility relationship among international stock markets. Furthermore, the quantile-varying beta design in this study relaxes a simple dual beta setting implied by Markov-switching models of Ramchand — Susmel (1998) and can identify dynamics of asymmetry in betas.
Bank selection factors in the banking industry: An empirical investigation from potential customers in Northern Cyprus
Authors: Katircioglu S. , Fethi S. , Unlucan D. , Dalci I.
Published: April 2011

This study investigates the bank selection criteria of undergraduate students who are future potential customers of banks from different regions of the world in a small island economy by comparing the selection factors of international students for the first time. Survey results of 258 respondents show that there are not huge differences in the bank selection factors between Turkish and non-Turkish international students in the case of a state university in North Cyprus. “Availability and convenient location of ATM services” and “speed and quality of service” are the most important factors for considering banks and their services for both Turkish and non-Turkish undergraduate students.
Effect of SiC Shape on The Crack-Healing Mechanism of Alumina/SiC Composite
Authors: Nakao Wataru , Osada Toshio , Yamane Kazuya , Yokouchi Masahiro , Takahashi Koji , Ando Kotoji
Published: April 2011

Crack-healing of structural ceramics is a most valuable technique to overcome their weak point such as surface cracks. Crack-healing ability appeared by admixing SiC to ceramics, because this function is to use the oxidation of SiC. Endowment of crack-healing ability as well as improvement in fracture toughness was expected to be achieved by compositing SiC whiskers. For this purpose, alumina / 30 vol% SiC whiskers and alumina/ 20vol% SiC whiskers/ 10 vol% SiC particles multi-composites were developed. Crack-healing ability and fracture toughness of these composites were investigated. Alumina/ 20 vol% SiC whiskers/ 10 vol% SiC particles multi-composite and alumina/ 30vol% SiC whiskers composite were found to have 1.43 times and 1.65 times higher fracture toughness than monolithic alumina, respectively. From the results of the strength recovery by crack-healing, alumina/ 20 vol% SiC whiskers/ 10 vol% SiC particles multi-composite and alumina / 30vol% SiC whiskers composite were found to be able to heal the pre-crack below 0.250 μm and 0.200 μm in surface length, respectively. In spite of the same SiC content, SiC particles and SiC whiskers multi-compositing enlarged the limit crack size to be able to crack-heal. On the other hand, increasing SiC whiskers content enhanced strength recovery of the specimen with the large crack above limit crack-size.
Modification of Ge2Sb2Te5 by the Addition of SiOx for Improved Operation of Phase Change Random Access Memory
Authors: Noh Jin-Seo , Suh Dong-Seok , Lee Sang Mock , Kim Kijoon H. P. , Shin Woong-Chul , Lee Eunhye , Kang Youn-Seon , Park Ju-Cheol , Kim Ki-Hong , Khang Yoonho
Published: April 2011

Conventional Ge2Sb2Te5 (GST) was modified by adding up a small amount of SiOx, using co-sputtering technique from multiple targets. The SiOx content was gradually increased by increasing the power applied to SiOx target, up to 8 volume percent. The sheet resistance of SiOx-containing GST exponentially increased, when the room-temperature-deposited samples were annealed at 300 °C. Transmission electron microscopy images revealed that no SiOx particulates were formed, which was confirmed by Gattan image filtering. It was indicated by x-ray diffraction patterns that the grain size of SiOx-containing GST is smaller than normal GST with lattice locally distorted at its crystalline state, suggesting that molecular SiOx is homogeneously distributed throughout the GST matrix. We observed that the crystallization temperature of SiOx-containing GST is gradually elevated by increasing the SiOx content, while the melting point decreased. These observations led to the reset current reduction, which is a critical requirement for the high density PRAM.
Material Properties of Rapid-solidified Ni-free Shape Memory TiNb Alloy
Authors: Kubo Yasuko , Yokoyama Masanori , Furuya Yasubumi
Published: April 2011

Ti-Ni shape memory alloy is used for bio-medical and industrial fields even if Ni is a substance which has strong allergic nature and carcinogenicity to a human body, then, Ti-Ni alloy system is in a prohibition tendency in the medical field in Europe in recent years. Therefore, Ni-free shape memory alloy is desired in the near future medical field. In this research, we pay our attention to the Ti-Nb alloy which has shape memory as well as superelastic effects. The Ti-Nb fiber was fabricated by using the ark melting and nozzelless rapid solidification method. The fiber samples were used to investigate the following characteristics relating with shape memory effect, that is to say, (1) cross sectional microstructure observation, (2) DSC(phase transformation temperature changes), (3) temperature-shape recovery relationship. Moreover, heat-treated effect on shape recovery phenomena was observed in comparison with the starting bulk material. Finally, the fundamental discussion to correlate the rapid-solidification process condition with the characteristic of Ti-Nb shape memory alloy for bio-medical engineering application was conducted.
The Dielectric, Piezoelectric and Pyroelectric Properties of (1-x)PST-xPZT Relaxor Ferroelectric Ceramics
Authors: Lan Dejun , Chen Qiang , Chen Yi , Xu Zhuo , Jiang Yihang , Yue Xi , Xiao Dingquan , Zhu Jianguo
Published: April 2011

Pb(Sc1/2Ta1/2)O3 (PST) relaxor ferroelectric ceramics were investigated widely in the past decades for their excellent pyroelectric, ferroelectric and dielectric properties and comprehensive applications in uncooled focal plane arrays infrared detectors and other electronic devices. However, some other ferroelectrics could be added into the PST ceramics to form the complex perovskite ferroelectrics with better electric properties. In this paper, (1-x)PST-xPZT(PSTZT) relaxor ferroelectric ceramics were prepared by wolframite precursor process (named two-step -sintering method, TSSM). The experiment results showed that the PSTZT ceramics with pure perovskite structure could be prepared by using TSSM. The temperature dependence of permittivity and dielectric loss of PSTZT ceramics were investigated in detail, which indicated that PSTZT ceramics showed partly diffusive phase transition with little frequency dispersion. The dielectric and pyroelectric properties of PSTZT ceramics were also investigated and discussed.
Side Chain Liquid Crystalline Thermoplastic Elastomers for Actuator and Electromechanical Applications
Authors: Verploegen Eric , McAfee LaRuth C. , Tian Lu , Verploegen Darren , Hammond Paula T.
Published: April 2011

The synthesis of a polystyrene-b-polyvinylmethylsiloxane-b-polystyrene diblock and triblock copolymer functionalized with liquid crystals exhibiting a smectic C* phase on the PVMS central block is described. The synthetic route is based on the anionic polymerization of styrene and trimethyltrivinylsiloxane monomers and the functionalization of resulting triblock copolymers. The resulting polymer can self assemble into a thermoplastic elastomer where the high Tg styrene blocks serve as physical crosslinks for a low Tg siloxane block. The presence of a smectic liquid crystalline phase and the block copolymer mesophase are observed across various temperature ranges depending on the length of the spacer connecting the liquid crystalline moiety to the polymer backbone. The influence of mechanical deformation upon the morphologies of the liquid crystalline and block copolymer mesophases was investigated. The interactions between the smectic LC and the block copolymer morphologies and their influence upon their respective orientations in response to shear fields are detailed. The parallel-transverse orientation of the hexagonally close packed (HCP) cylinders of the block copolymer morphology and the smectic liquid crystalline phase, respectively, was observed for melt fiber drawn samples. However, the transverse-perpendicular orientation was observed for liquid crystalline block copolymers that experienced oscillatory shear. The transverse orientation of HCP cylinders was observed while shearing took place above the smectic to isotropic transition temperature, indicating that the presence of an isotropic liquid crystalline phase alters the orientation of the block copolymer morphology. Additionally, it was found that the spacer length was a key factor in the clearing points for the smectic liquid crystalline phase, as well as significantly influencing the nanophase segregation of the block copolymer.
Electronic Structure Calculations of Electronic and Structural Properties of Plutonium 115 Compounds
Authors: Wills John , Lizarraga Raquel , Joyce John J. , Durakiewicz Tomasz , Sarrao John L. , Morales Luis , Eriksson Olle
Published: April 2011

The 5f electronic states in elemental Pu and Pu compounds exhibit elements of both itinerant and localized behavior. Several first-principles calculations have been presented to describe this balance, differing in the manner in which electron correlation is included in the calculation. This paper describes a calculations performed with the Mixed Level Model (MLM), presenting calculated results for the two Pu compounds, PuRhGa5 and PuCoGa5. The MLM results are compared with other calculations and the differences discussed.
Theory of the Knight Shift and Spin-Lattice Relaxation Rate in Pu-115
Authors: Bang Yunkyu , Graf Matthias J. , Curro Nicholas J. , Balatsky Alexander J.
Published: April 2011

We calculated the Knight shift and spin-lattice relaxation rates of Pu-115 compounds assuming d-wave superconductivity in the presence of strong impurity scattering. We discuss the implications for recent measurements of the spin-lattice relaxation rate in the Pu-115 compound PuRhGa5 by Sakai and coworkers [J. Phys. Soc. Jpn. 74, 1710 (2005)] and present a prediction for the corresponding Knight shift. In addition, we noticed a significant round-off of the spin-lattice relaxation rate 1/T1 just above the superconducting transition temperature that is not observed in the sister compound PuCoGa5. It appears that in PuRhGa5 superconductivity is mediated by spin fluctuations, too. This provides additional support to the scenario of superconducting pairing mediated by spin fluctuations in the Pu-115 compounds similar to the Ce-115 compounds and the high-temperature copper-oxide superconductors.
Multi-scale modeling of self-irradiation effects in plutonium alloys - Molecular dynamic simulations results
Authors: Berlu Lilian , Rosa Gaelle , Faure Philippe , Baclet Nathalie , Jomard Gérald
Published: April 2011

The plutonium α decay leads to the formation of numerous point defects in the metal structure. The multi-scale modeling of self-irradiation effects in plutonium alloys needs a quantitative knowledge of defects population properties. In this work, we initiated a parametric study of molecular dynamics displacement cascade simulations to get properties of defects microstructure such as number of point defects, number and size of clusters, spatial repartition and spatial expansion of the cascade. These data constitute some of the input parameters for the mesoscopic scale simulations. First results obtained for two 2 keV energy cascades simulations are presented and discussed.
Ultrafast dynamics of the Itinerant Antiferromagnet UNiGa5
Authors: Chia Ee Min Elbert , Lee H. J. , Hur Namjung , Bauer E. D. , Durakiewicz T. , Averitt R. D. , Sarrao J. L. , Taylor A. J.
Published: April 2011

Time-resolved photoinduced reflectivity data were measured for the itinerant antiferromagnet UNiGa5 (TN ≈ 85 K) from room temperature down to 10 K. The relaxation time τ increases sharply near TN, which we attribute to the opening of a spin gap. In addition, at the lowest temperatures τ increases with a T1 dependence, which is similar to that shown by the heavy fermion YbAgCu4, but with no blocking of electron-phonon scattering within the DOS peak. The transient amplitude increase at TN with a temperature dependence that is consistent with the appearance of a spin gap.
Affects of Hydrogen Peroxide on the Stability of Becquerelite
Authors: Kubatko Karrie-Ann , Unruh Daniel , Burns Peter C.
Published: April 2011

While the majority of studies of alteration of UO2 and commercial spent nuclear fuel under simulated geological repository conditions have emphasized the importance of uranyl oxide hydrates and uranyl silicates, the influence of peroxide on repository performance has been largely overlooked. There is considerable evidence that uranyl peroxides will be important alteration phases of nuclear waste, and that these phases may impact the long-term performance of a geologic repository such as Yucca Mountain. Here we report the thermodynamics and kinetics of becquerelite, Ca[(UO2)6O4(OH)6](H2O)8, in the presence of solutions containing hydrogen peroxide. Thermodynamic calculations reveal that in solutions containing 3.5 × 10-6 M hydrogen peroxide, studtite is thermodynamically favorable over becquerelite at 298 K. To access the kinetics of this reaction, batch experiments were conducted by the reaction of becquerelite and solutions containing hydrogen peroxide. In the presence of 0.1 M hydrogen peroxide, becquerelite altered to studtite within eight hours.
High-Throughput Screening of Barrier and Adhesive Behavior of Polymeric Coatings
Authors: Grunlan Jaime C. , Mehrabi Ali R.
Published: April 2011

A combinatorial factory for the preparation and screening of polymeric coatings was developed. Coating formulations were prepared and coated using novel combinatorial techniques to obtain libraries of varying composition and thickness. The thickness of each film in a combinatorial array is rapidly determined via visible-light absorbance of optical dyes in conjunction with the Beer-Lambert relationship. These combinatorial libraries were then tested and screened using a variety of custom-made high-throughput methods. Combinatorial screening of oxygen and moisture vapor transmission rate, along with adhesive properties, are shown here. OTR and MVTR are determined using spectroscopic techniques. For adhesion, a spherical probe adhesive tester is able to generate parameters linked to tack, peel, and shear in one measurement. In addition to describing the testing methodology, benefits and shortcomings of these techniques will be highlighted.
Combinatorial Catalysis for Hydrogen Production from Ethanol
Authors: Yamada Yusuke , Akita Tomoki , Umegaki Tetsuo , Mathew Thomas , Ueda Atshushi , Shioyama Hiroshi , Kobayashi Tetsuhiko
Published: April 2011

Combinatorial catalysis on EtOH steam reforming has been performed on referring catalysis database on elemental reactions of EtOH SR.
High-throughput characterization of shape memory thin films using automated temperature-dependent resistance measurements
Authors: Thienhaus Sigurd , Zamponi Christiane , Rumpf Holger , Hattrick-Simpers Jae , Takeuchi Ichiro , Ludwig Alfred
Published: April 2011

Shape memory alloy (SMA) thin films are used as actuator materials in MEMS due to their unique properties. Binary thin films with a composition close to Ni50Ti50 are well-established materials, whereas ternaries like NiTiCu, NiTiPd, NiTiHf are less studied. Furthermore, new alloys are being developed which show a magnetic shape memory effect, e.g. Ni2MnGa. For the optimization of known, and the development of new, SMA thin films, a fast and reliable characterization technology is needed, which rapidly identifies the transformation temperatures (i.e. martensite and austenite start and finish temperatures) for a range of material compositions deposited on a whole wafer. In this paper, automated temperature-dependent resistance measurements are discussed as a means which yields the thermal hysteresis of the investigated thin films. Results of monitoring the uniformity of shape memory film depositions on the wafer level, as well as results on the use of this method as a tool for screening for new SMA films by characterization of materials libraries are reported.
Focused ion beam microscope as an analytical tool for nanoscale characterization of gradient-formulated polymeric sensor materials
Authors: Dovidenko Katharine , Potyrailo Radislav A. , Grande Games
Published: April 2011

In this study, we are demonstrating localized nano-scale analysis of sensor materials which are developed using combinatorial gradient approach. Our technique based on Focused Ion Beam cross-sectioning at specific locations affords establishing metal nano-particles concentrations at best-performing area(s) of gradient-formulated polymer samples. We have achieved three-dimensional characterization/mapping of nano-fillers (30-100 nm metal particles) in composite thin films on variety of substrates.
Computational DFT Study of ZrSiO4 Polymorphs: Microelectronic, Nuclear Safety and Geological Implications
Authors: Korkin Anatoli , Kamisaka Hideyuki , Yamashita Koichi , Safonov Andrey , Bagatur'yants Alexander
Published: April 2011

Zirconium silicate is an extremely durable materials with the variety of useful optical and electronic properties and broad range of existing and potential applications. Using Density Functional Theory (DFT) in local density approximation (LDA) and generalized gradient approximation (GGA) with plane wave (PW) basis set we have revealed eight new polymorphs of ZrSiO4 within the energy range ∼1 eV above the most stable zircon which have higher and lower density than experimentally known zircon and reidite. Two structures, which have both silicon and zirconium atoms six-fold coordinated, orthorhombic AlTaO4-like (alumotantite) and monoclinic PbWO4-like (raspite), have similar energies at GGA level ∼0.35 eV above reidite and density intermediate between zircon and reidite. Among two low-density structures, which can be potentially revealed experimentally in the nanocrystalline thin films, the orthorhombic CaSO4-like form has energy similar to reidite but much lower density. We also conducted a comparative study of existing ZrO2 and SiO2 polymorphs, which demonstrates the higher accuracy of GGA approach.
Information-Based Development of New Radiation Detection Materials
Authors: Ferris Kim , webb-robertson bobbie-jo m , jones dumont m
Published: April 2011

With our present concern for a secure environment, the development of new radiation detection materials has focused on the capability of identifying potential radiation sources at increased sensitivity levels. As the initial framework for a materials-informatics approach to radiation detection materials, we have explored the use of both supervised (Support Vector Machines – SVM and Linear Discriminant Analysis – LDA) and unsupervised (Principal Component Analysis – PCA) learning methods for the development of structural signature models. Application of these methods yields complementary results, both of which are necessary to reduce parameter space and variable degeneracy. Using a crystal structure classification test, the use of the nonlinear SVM significantly increases predictive performance, suggesting trade-offs between smaller descriptor spaces and simpler linear models.