bluuebunny/crossref_metadata_2025 huggingface dataset:
Lift-off of Porous Germanium Layers
Authors: Rojas E. Garralaga , Hensen J. , Carstensen J. , Föll H. , Brendel R.
Published: April 2011

We demonstrate reproducible formation of mesoporous germanium layers suitable for solar energy applications by electrochemical etching in highly concentrated electrolytes. For long anodization times or thick layer formation a porosity gradient is observed leading eventually to high porosity regions and cavity formation at the bottom of the porous layer. A 30 min annealing step at a temperature of 575°C in hydrogen atmosphere allows for reorganization and subsequent lift-off. The mean surface roughness increases from 0.31 nm for unprocessed Ge up to 7.85 nm for reorganized Ge as measured by atomic force microscopy. μ-Raman confocal spectroscopy analysis confirms that etching and annealing do not affect the crystalline structure.
Exercise-mediated changes in conduit artery wall thickness in humans: role of shear stress
Authors: Thijssen Dick H. J. , Dawson Ellen A. , van den Munckhof Inge C. L. , Tinken Toni M. , den Drijver Evert , Hopkins Nicola , Cable N. Timothy , Green Daniel J.
Published: April 2011

Episodic increases in shear stress have been proposed as a mechanism that induces training-induced adaptation in arterial wall remodeling in humans. To address this hypothesis in humans, we examined bilateral brachial artery wall thickness using high-resolution ultrasound in healthy men across an 8-wk period of bilateral handgrip training. Unilaterally, shear rate was attenuated by cuff inflation around the forearm to 60 mmHg. Grip strength, forearm volume, and girth improved similarly between the limbs. Acute bouts of handgrip exercise increased shear rate ( P < 0.005) in the noncuffed limb, whereas cuff inflation successfully decreased exercise-induced increases in shear. Brachial blood pressure responses similarly increased during exercise in both the cuffed and noncuffed limbs. Handgrip training had no effect on baseline brachial artery diameter, blood flow, or shear rate but significantly decreased brachial artery wall thickness after 6 and 8 wk (ANOVA, P < 0.001) and wall-to-lumen ratio after week 8 (ANOVA, P = 0.005). The magnitude of decrease in brachial artery wall thickness and wall-to-lumen ratio after exercise training was similar in the noncuffed and cuffed arms. These results suggest that exercise-induced changes in shear rate are not obligatory for arterial wall remodeling during a period of 8 wk of exercise training in healthy humans.
Role of splanchnic constriction in governing the hemodynamic responses to gravitational stress in conscious dogs
Authors: Wong Brett J. , Sheriff Don D.
Published: April 2011

Octreotide is a somatostatin analog that constricts the splanchnic circulation, thereby improving orthostatic tolerance. We tested the hypotheses that octreotide improves orthostatic tolerance by 1)increasing cardiac filling (right atrial) pressure via reductions in vascular capacity; 2) by causing an upward (i.e., cranial) shift of the hydrostatic indifferent point; and 3) by increasing arterial pressure via a reduction in total vascular conductance. Studies were carried out in acepromazine-sedated, hexamethonium-treated atrioventricular-blocked conscious dogs lightly restrained in lateral recumbency. Beat-by-beat cardiac output was held constant via computer-controlled ventricular pacing at rest and during 30 s of 30° head-up tilt. Octreotide (1.5 μg/kg iv) raised right atrial pressure by 0.5 mmHg and raised mean arterial pressure by 11 mmHg by reducing total vascular conductance (all P < 0.05). Right atrial pressure fell by a similar amount in response to tilting before and after octreotide, thus there was no difference in location of the hydrostatic indifferent point. These data indicate that octreotide improves orthostatic tolerance by decreasing total vascular conductance and by increasing cardiac filling pressure via a reduction in unstressed vascular volume and not by eliciting a cranial shift of the location of the hydrostatic indifferent point.
EZH2-Mediated Concordant Repression of Wnt Antagonists Promotes β-Catenin–Dependent Hepatocarcinogenesis
Authors: Cheng Alfred S.L. , Lau Suki S. , Chen Yangchao , Kondo Yutaka , Li May S. , Feng Hai , Ching Arthur K. , Cheung Kin F. , Wong Hoi K. , Tong Joanna H. , Jin Hongchuan , Choy Kwong W. , Yu Jun , To Ka F. , Wong Nathalie , Huang Tim H.-M. , Sung Joseph J.Y.
Published: April 2011

Enhancer of zeste homolog 2 (EZH2) is the catalytic subunit of the Polycomb-repressive complex 2 (PRC2) that represses gene transcription through histone H3 lysine 27 trimethylation (H3K27me3). Although EZH2 is abundantly present in various cancers, the molecular consequences leading to oncogenesis remain unclear. Here, we show that EZH2 concordantly silences the Wnt pathway antagonists operating at several subcellular compartments, which in turn activate Wnt/β-catenin signaling in hepatocellular carcinomas (HCC). Chromatin immunoprecipitation promoter array and gene expression analyses in HCCs revealed EZH2 occupancy and reduced expression of Wnt antagonists, including the growth-suppressive AXIN2, NKD1, PPP2R2B, PRICKLE1, and SFRP5. Knockdown of EZH2 reduced the promoter occupancy of PRC2, histone deacetylase 1 (HDAC1), and H3K27me3, whereas the activating histone marks were increased, leading to the transcriptional upregulation of the Wnt antagonists. Combinatorial EZH2 and HDAC inhibition dramatically reduced the levels of nuclear β-catenin, T-cell factor–dependent transcriptional activity, and downstream pro-proliferative targets CCND1 and EGFR. Functional analysis revealed that downregulation of EZH2 reduced HCC cell growth, partially through the inhibition of β-catenin signaling. Conversely, ectopic overexpression of EZH2 in immortalized hepatocytes activated Wnt/β-catenin signaling to promote cellular proliferation. In human HCCs, concomitant overexpression of EZH2 and β-catenin was observed in one-third (61/179) of cases and significantly correlated with tumor progression. Our data indicate that EZH2-mediated epigenetic silencing contributes to constitutive activation of Wnt/β-catenin signaling and consequential proliferation of HCC cells, thus representing a novel therapeutic target for this highly malignant tumor. Cancer Res; 71(11); 4028–39. ©2011 AACR.
Mutationally Activated BRAFV600E Elicits Papillary Thyroid Cancer in the Adult Mouse
Authors: Charles Roch-Philippe , Iezza Gioia , Amendola Elena , Dankort David , McMahon Martin
Published: April 2011

Mutated BRAF is detected in approximately 45% of papillary thyroid carcinomas (PTC). To model PTC, we bred mice with adult-onset, thyrocyte-specific expression of BRAFV600E. One month following BRAFV600E expression, mice displayed increased thyroid size, widespread alterations in thyroid architecture, and dramatic hypothyroidism. Over 1 year, without any deliberate manipulation of tumor suppressor genes, all mice developed PTC displaying nuclear atypia and marker expression characteristic of the human disease. Pharmacologic inhibition of MEK1/2 led to decreased thyroid size, restoration of thyroid form and function, and inhibition of tumorigenesis. Mice with BRAFV600E-induced PTC will provide an excellent system to study thyroid tumor initiation and progression and the evaluation of inhibitors of oncogenic BRAF signaling. Cancer Res; 71(11); 3863–71. ©2011 AACR.
MST1 Is a Multifunctional Caspase-Independent Inhibitor of Androgenic Signaling
Authors: Cinar Bekir , Collak Filiz Kisaayak , Lopez Delia , Akgul Seckin , Mukhopadhyay Nishit K. , Kilicarslan Murat , Gioeli Daniel G. , Freeman Michael R.
Published: April 2011

The MST1 serine–threonine kinase, a component of the RASSF1-LATS tumor suppressor network, is involved in cell proliferation and apoptosis and has been implicated in cancer. However, the physiologic role of MST1 in prostate cancer (PCa) is not well understood. Here, we investigated the possibility of a biochemical and functional link between androgen receptor (AR) and MST1 signaling. We showed that MST1 forms a protein complex with AR and antagonizes AR transcriptional activity as shown by coimmunoprecipitation (co-IP), promoter reporter analysis, and molecular genetic methods. In vitro kinase and site-specific mutagenesis approaches indicate that MST1 is a potent AR kinase; however, the kinase activity of MST1 and its proapoptotic functions were shown not to be involved in inhibition of AR. MST1 was also found in AR–chromatin complexes, and enforced expression of MST1 reduced the binding of AR to a well-characterized, androgen-responsive region within the prostate-specific antigen promoter. MST1 suppressed PCa cell growth in vitro and tumor growth in mice. Because MST1 is also involved in regulating the AKT1 pathway, this kinase may be an important new link between androgenic and growth factor signaling and a novel therapeutic target in PCa. Cancer Res; 71(12); 4303–13. ©2011 AACR.
Consequences of Epidermal Growth Factor Receptor (ErbB1) Loss for Vascular Smooth Muscle Cells From Mice With Targeted Deletion of ErbB1
Authors: Schreier Barbara , Döhler Maria , Rabe Sindy , Schneider Bettina , Schwerdt Gerald , Ruhs Stefanie , Sibilia Maria , Gotthardt Michael , Gekle Michael , Grossmann Claudia
Published: April 2011

Objective—

Pathophysiological effects of the epidermal growth factor receptor (EGFR or ErbB1) include vascular remodeling. EGFR transactivation is proposed to contribute significantly to heterologous signaling and remodeling in vascular smooth muscle cells (VSMC).

Methods and Results—

We investigated the importance of EGFR in primary VSMC from aorta of mice with targeted deletion of the EGFR (
EGFR

Δ/Δ
VSMC

→VSMC
EGFR−/−
and
EGFR

Δ/+
VSMC

→VSMC
EGFR+/−
) and the respective littermate controls (
EGFR

+/+
VSMC

→VSMC
EGFR+/+
) with respect to survival, pentose phosphate pathway activity, matrix homeostasis, extracellular signal–regulated kinase 1/2 (ERK1/2) phosphorylation, and Ca
2+
homeostasis. In VSMC
EGFR−/−
, epidermal growth factor–induced signaling was abolished; VSMC
EGFR+/−
showed an intermediate phenotype. EGFR deletion enhanced spontaneous cell death, reduced pentose phosphate pathway activity, disturbed cellular matrix homeostasis (collagen III and fibronectin), and abolished epidermal growth factor sensitivity. In VSMC
EGFR−/−
endothelin-1- or α
1
-adrenoceptor-induced ERK1/2 phosphorylation and the fraction of Ca
2+
responders were significantly reduced, whereas responsive cells showed a significantly stronger Ca
2+
signal. Oxidative stress (H
2
O
2
) induced ERK1/2 activation in VSMC
EGFR+/+
and VSMC
EGFR+/−
but not in VSMC
EGFR−/−
. The Ca
2+
signal was enhanced in VSMC
EGFR−/−
, similar to purinergic stimulation by ATP.

Conclusion—

In conclusion, EGFR was found to be important for basal VSMC homeostasis and ERK1/2 activation by the tested G-protein–coupled receptors or radical stress. Ca
2+
signaling was modulated by EGFR differentially with respect to the fraction of responders and magnitude of the signal. Thus, EGFR seems to be Janus-faced for VSMC biology.
Evidence of Platelet Activation at Medically Used Hypothermia and Mechanistic Data Indicating ADP as a Key Mediator and Therapeutic Target
Authors: Straub Andreas , Krajewski Stefanie , Hohmann Jan David , Westein Erik , Jia Fu , Bassler Nicole , Selan Carly , Kurz Julia , Wendel Hans Peter , Dezfouli Shala , Yuan Yuping , Nandurkar Harshal , Jackson Shaun , Hickey Michael J. , Peter Karlheinz
Published: April 2011

Objective—

Hypothermia is used in various clinical settings to inhibit ischemia-related organ damage. However, prothrombotic effects have been described as potential side effects. This study aimed to elucidate the mechanism of hypothermia-induced platelet activation and subsequent prothrombotic events and to develop preventative pharmacological strategies applicable during clinically used hypothermia.

Methods and Results—

Platelet function was investigated ex vivo and in vivo at clinically used hypothermia (28°C/18°C). Hypothermic mice demonstrated increased expression of platelet activation marker P-selectin, platelet-leukocyte aggregate formation, and thrombocytopenia. Intravital microscopy of FeCl
3
-injured murine mesenteric arteries revealed increased platelet thrombus formation with hypothermia. Ex vivo flow chamber experiments indicated increased platelet-fibrinogen adhesion under hypothermia. We show that hypothermia results in reduced ADP hydrolysis via reduction of CD39 (E-NTPDase1) activity, resulting in increased levels of ADP and subsequent augmented primary and secondary platelet activation. In vivo administration of ADP receptor P
2
Y
12
antagonists and recombinant soluble CD39 prevented hypothermia-induced thrombus formation and thrombocytopenia, respectively.

Conclusion—

The platelet agonist ADP plays a key role in hypothermia-induced platelet activation. Inhibition of receptor binding or hydrolysis of ADP has the potential to protect platelets against hypothermia-induced activation. Our findings provide a rational basis for further evaluation of novel antithrombotic strategies in clinically applied hypothermia.
Tetrahydrobiopterin Deficiency and Nitric Oxide Synthase Uncoupling Contribute to Atherosclerosis Induced by Disturbed Flow
Authors: Li Li , Chen Wei , Rezvan Amir , Jo Hanjoong , Harrison David G.
Published: April 2011

Objective—

Tetrahydrobiopterin (BH
4
) is a critical cofactor for nitric oxide (NO) synthesis by NO synthase (NOS). Recently, we demonstrated that disturbed flow produced by partial carotid ligation decreases BH
4
levels in vivo. We therefore aimed to determine whether atherosclerosis induced by disturbed flow is due to BH
4
deficiency and NOS uncoupling and whether increasing BH
4
would prevent endothelial dysfunction, plaque inflammation, and atherosclerosis.

Methods and Results—

We produced a region of disturbed flow in apolipoprotein E
−/−
mice using partial carotid ligation and fed these animals a high-fat diet. This caused endothelial NOS uncoupling as characterized by increased vascular superoxide production, altered vascular reactivity, and a change in endothelial NOS migration on low-temperature gel. These perturbations were accompanied by severe atherosclerosis, infiltration of T cells and macrophages, and an increase in cytokine production. Treatment with BH
4
recoupled NOS, decreased superoxide production, improved endothelium-dependent vasodilatation, and virtually eliminated atherosclerosis. BH
4
treatment also markedly reduced vascular inflammation and improved the cytokine milieu induced by disturbed flow.

Conclusion—

Our results highlight a key role of BH
4
deficiency and NOS uncoupling in atherosclerosis induced by disturbed flow and provide insight into the effect of modulating vascular BH
4
levels on atherosclerosis and inflammation at these sites of the circulation.
Is There an Association Between External Cardioversions and Long-Term Mortality and Morbidity?
Authors: Elayi Claude S. , Whitbeck Matthew G. , Charnigo Richard , Shah Jignesh , Macaulay Tracy E. , Morales Gustavo , Gurley John C. , Kakavand Bahram , Thal Sergio , Ching Chi Keong , Khaykin Yaariv , Verma Atul , Barrett Conor , Bai Rong , Di Biase Luigi , Patwardhan Abhijit , Moliterno David J. , Natale Andrea ,   the AFFIRM Study Investigators
Published: April 2011

Background—

Cardiac electric therapies effectively terminate tachyarrhythmias. Recent data suggest a possible increase in long-term mortality associated with implantable cardioverter-defibrillator shocks. Little is known about the association between external cardioversion episodes (ECVe) and long-term mortality. We sought to assess the safety of repeated ECVe with regard to cardiovascular mortality and morbidity.

Methods and Results—

We analyzed the data of the 4060 patients from the AFFIRM (Atrial Fibrillation Follow-up Investigation of Rhythm Management) trial. In particular, associations of ECVe with all-cause mortality, cardiovascular mortality, and hospitalizations after ECVe were studied. Over an average follow-up of 3.5 years, 660 (16.3%) patients died, 331 (8.2%) from cardiovascular causes. A total of 207 (5.1%) and 1697 (41.8%) patients had low ejection fraction and nonparoxysmal atrial fibrillation, respectively; 2460 patients received no ECVe, whereas 1600 experienced ≥1 ECVe. Death occurred in 412 (16.7%), 196 (16.5%), 39 (13.5%), and 13 (10.4%) of patients with 0, 1, 2, and ≥3 ECVe, respectively. There was no significant association between ECVe and mortality within any of the 4 subgroups defined by ejection fraction and atrial fibrillation type, although myocardial infarction, coronary artery bypass graft, and digoxin were significantly associated with death (estimated hazard ratios, 1.65, 1.59, and 1.62, respectively;
P
<0.0001). ECVe were associated with increased cardiac hospitalization reported at the next follow-up visit (39.3% versus 5.8%; estimated odds ratio, 1.39;
P
<0.0001).

Conclusions—

In the AFFIRM study, there was no significant association between ECVe and long-term mortality, even though ECVe were associated with increased hospitalizations from cardiac causes. Digoxin, myocardial infarction, and coronary artery bypass graft were significantly associated with mortality.
Sarcomere Protein Gene Mutations in Patients With Apical Hypertrophic Cardiomyopathy
Authors: Gruner Christiane , Care Melanie , Siminovitch Katherine , Moravsky Gil , Wigle E. Douglas , Woo Anna , Rakowski Harry
Published: April 2011

Background—

Apical hypertrophic cardiomyopathy (HCM) is a unique form of HCM with left ventricular hypertrophy confined to the cardiac apex. The purpose of our study was to report genetic findings in a large series of unrelated patients with apical HCM and compare them with a nonapical HCM cohort.

Methods and Results—

Overall, 429 patients with HCM underwent genetic testing. The panel included 8 sarcomere protein genes and 3 other genes
(GLA, PRKAG2,
and
LAMP2).
Sixty-one patients were diagnosed with apical HCM. A positive genotype was found in 8 patients with apical HCM. The genotype-positive and genotype-negative patients had similar maximal wall thicknesses (17.5±3.5 mm versus 17.6±3.3 mm,
P
=0.71) and similar frequency of HCM-related events (2/8; 25% versus 13/53; 25%;
P
=0.98). Thirteen percent with apical HCM and 40% with nonapical HCM had a positive genotype (
P
<0.001) most often involving the
MYBPC3
and
MYH7
genes.

Conclusions—

In apical HCM, a positive genotype was found less frequently than in nonapical HCM, and it was most often involving
MYBPC3
and
MYH7
genes. Only 13% of patients with apical HCM were found to be genotype positive, indicating that genome-wide association studies and gene expression profiling are needed for better understanding of the genetic background of the disease. There was no significant genotype-phenotype correlation in our cohort with apical HCM.
Common Genetic Variants, QT Interval, and Sudden Cardiac Death in a Finnish Population-Based Study
Authors: Noseworthy Peter A. , Havulinna Aki S. , Porthan Kimmo , Lahtinen Annukka M. , Jula Antti , Karhunen Pekka J. , Perola Markus , Oikarinen Lasse , Kontula Kimmo K. , Salomaa Veikko , Newton-Cheh Christopher
Published: April 2011

Background—

Although sudden cardiac death (SCD) is heritable, its genetic underpinnings are poorly characterized. The QT interval appears to have a graded relationship to SCD, and 35% to 45% of its variation is heritable. We examined the relationship among recently reported common genetic variants, QT interval, and SCD.

Methods and Results—

We genotyped 15 common (minor allele frequency >1%) candidate single nucleotide polymorphisms (SNPs), based on association with the QT interval in prior studies, in individuals in 2 cohort studies (Health 2000, n=6597; Mini-Finland, n=801). After exclusions, we identified 116 incident SCDs from the remaining sample (n=6808). We constructed a QT genotype score (QT
score
) using the allele copy number and previously reported effect estimates for each SNP. Cox proportional hazards models adjusting for age, sex, and geographical area were used for time to SCD analyses. The QT
score
was a continuous independent predictor of the heart rate–corrected QT interval (
P
<10
−107
). Comparing the top with the bottom quintile of QT
score
, there was a 15.6-ms higher group mean QT interval (
P
<10
−84
). A 10-ms increase in the observed QT interval was associated with an increased risk of SCD (hazard ratio, 1.19; 95% confidence interval, 1.07 to 1.32;
P
=0.002). There was no linear relationship between QT
score
and SCD risk; although in post hoc secondary analysis there was increased risk in the top compared with the middle QT
score
quintile (hazard ratio, 1.92; 95% confidence interval, 1.05 to 3.58;
P
=0.04).

Conclusions—

Our study strongly replicates the relationship between common genetic variants and the QT interval and confirms the relationship between the QT interval and SCD but does not show evidence for a linear relationship between QT
score
and SCD risk.
Comparative Lipidomics Profiling of Human Atherosclerotic Plaques
Authors: Stegemann Christin , Drozdov Ignat , Shalhoub Joseph , Humphries Julia , Ladroue Christophe , Didangelos Athanasios , Baumert Mark , Allen Mark , Davies Alun H. , Monaco Claudia , Smith Alberto , Xu Qingbo , Mayr Manuel
Published: April 2011

Background—

We sought to perform a systematic lipid analysis of atherosclerotic plaques using emerging mass spectrometry techniques.

Methods and Results—

A chip-based robotic nanoelectrospray platform interfaced to a triple quadrupole mass spectrometer was adapted to analyze lipids in tissue sections and extracts from human endarterectomy specimens by shotgun lipidomics. Eighteen scans for different lipid classes plus additional scans for fatty acids resulted in the detection of 150 lipid species from 9 different classes of which 24 were detected in endarterectomies only. Further analyses focused on plaques from symptomatic and asymptomatic patients and stable versus unstable regions within the same lesion. Polyunsaturated cholesteryl esters with long-chain fatty acids and certain sphingomyelin species showed the greatest relative enrichment in plaques compared to plasma and formed part of a lipid signature for vulnerable and stable plaque areas in a systems-wide network analysis. In principal component analyses, the combination of lipid species across different classes provided a better separation of stable and unstable areas than individual lipid classes.

Conclusions—

This comprehensive analysis of plaque lipids demonstrates the potential of lipidomics for unraveling the lipid heterogeneity within atherosclerotic lesions.
Globalization and Diversity in Cultural Fields: Comparative Perspectives on Television, Music, and Literature
Authors: Dowd Timothy J. , Janssen Susanne
Published: April 2011

Scholarship in the social sciences and the humanities often approaches globalization, particularly that involving that media content, by emphasizing such concepts as “imperialism” and “hybridization.” While theoretically rich, this scholarship can sometimes given little attention to how various actors and arrangements can impinge on the global flow and circulation of media content. This special issue seeks to move beyond such limitations by wedding theoretical concerns with an emphasis on empirical evidence—thereby heeding the specific contexts in which globalization unfolds. Our introductory essay thus provides a brief overview of the articles contained within this issue.
A Cultural Globalization of Popular Music? American, Dutch, French, and German Popular Music Charts (1965 to 2006)
Authors: Achterberg Peter , Heilbron Johan , Houtman Dick , Aupers Stef
Published: April 2011

In this article, the authors address the question of whether and how the appreciation of popular music consumers has globalized in the four decades since the mid-1960s. They use information from American, Dutch, French, and German popular music charts from 1965 through 2006. They find no corroboration for an overall trend toward an internationalization of hits. However, important shifts are noticeable underneath the surface. For the period up until 1989, the authors find increasing international diversity as well as increasing Americanization. From the 1990s onwards, they find a growing popularity of national music in all three European countries in the study.
Classifying Popular Music in the United States and the Netherlands
Authors: van Venrooij Alex
Published: April 2011

This article focuses on the classification of popular music by newspaper critics in the United States and the Netherlands. By using the “mentions technique” of Rosengren, the author investigates cross-national differences in the use of commercial, aesthetic, and racial logics in the classification of popular music artists, relating them to field-level and macrostructural differences between the United States and the Netherlands. U.S. reviewers are found to mention commercially successful artists more often than their Dutch counterparts. Racial boundaries appear to be strong in both countries.
Mechanical properties of hemp-lime reinforced mortars: influence of the chemical treatment of fibers
Authors: Le Troëdec M. , Dalmay P. , Patapy C. , Peyratout C. , Smith A. , Chotard T.
Published: April 2011

In addition to being an environmental-friendly material, hemp fibers are also inexpensive reinforcements in thermoplastics or concrete composites, due to their intrinsic mechanical, thermal, and acoustic properties. However, chemical treatments of fibers are required to enhance the matrix/fiber interface. In this article, the influence of the addition of hemp fibers chemically treated or not, on the mechanical properties of a lime composite was investigated. Mechanical properties were evaluated by ultrasonic pulse echography and four-point bending test associated with acoustic emission analysis. The physical and chemical surface modifications of the hemp fibers were monitored with gas chromatography and scanning electron microscopy. It appears that chemical modification of the fiber surface degrades the amorphous materials present in the fiber structure, which results in an increase in the surface reactivity and also improves the mechanical properties of the composites.
Navigating the Terrain of Third Space: Tensions With/In Relationships in School-University Partnerships
Authors: Martin Susan D. , Snow Jennifer L. , Franklin Torrez Cheryl A.
Published: April 2011

Using theoretical conceptions of third space and hybrid teacher education, the authors engaged in a collaborative self-study of their practices as university-based teacher educators working in student teaching partnership settings. The authors sought to understand ways in which hybrid teacher educators foster and mediate relationships to work toward a collective third space. In this article, the authors describe the nature of relationships in their work, the tensions wrought by complexities of these relationships, and ways they negotiated tensions to foster relationships that productively mediated processes of teacher education. The authors also propose a framework for moving beyond traditional notions of oppositional triadic relationships of student teacher, mentor teacher, and supervisor in recognition of complex social interactions in the third space.
The Impact of Principal Leadership Behaviors on the Efficacy of New and Experienced Middle School Teachers
Authors: Walker Jeff , Slear Sharon
Published: April 2011

There is a positive relationship between high levels of teacher efficacy and increased student achievement as well as a positive link between principal behavior and teacher efficacy. A diverse group of middle school teachers from a mid-Atlantic state were surveyed. Responses from 366 teachers were analyzed to determine whether various principal behaviors affected the efficacy of new and experienced teachers differently. Findings suggest that teacher efficacy is significantly affected by principal behaviors based on years of teaching experience.
One-year prognosis of patients with normal myocardial perfusion imaging using technitium-99m sestamibi in suspected coronary artery disease: a single-center experience of 1,047 patients
Authors: Raziei Ghasem , Tavakoli Alireza , Shahram Seifollahi asl  , Amoiei Mahasti , Javadi Hamid , Assadi Majid
Published: April 2011

Introduction: The aim of the present study was to evaluate the clinical outcome of a normal stress technetium-99m (99mTc)-Sestamibi single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) with different probabilities of coronary artery disease (CAD).

Material and Methods: A total of 1,047 subjects with a normal 99mTc-MIBI SPECT were followed up for one year and hard and soft cardiac events were assessed. Hard cardiac events were defined as cardiac death or non-fatal myocardial infarction (MI). Soft cardiac events included the patient’s development of recurrent chest pain requiring coronary revascularization or significant stenosis in coronary arteries on angiography.

Results: Overall, 1,047 patients (248 men and 799 women; mean age: 60.07 ± 12.31, range 29—92) were enrolled. Three hard cardiac events occurred in the groups; two had cardiac arrest and one non-fatal MI. As a result, the annualized hard cardiac event rate was 0.28%, the annualized cardiac mortality rate was 0.19%, and the rate of overall annualized cardiac events was 1.25%. Furthermore, there was a significant difference in cardiac events among patients with various pretest likelihoods of CAD (p value=0.04).

Conclusion: Our data confirmed that patients with a normal 99mTc-Sestamibi myocardial SPECT are associated with a very low incidence of cardiovascular events.
Migraine, migraine aura, and cervical artery dissection: A systematic review and meta-analysis
Authors: Rist Pamela M , Diener Hans-Christoph , Kurth Tobias , Schürks Markus
Published: April 2011

Objective: We evaluated the current evidence on the association between migraine, including aura status, and cervical artery dissection.

Methods: We performed a systematic review and meta-analysis of studies investigating the association between migraine or migraine subtypes (e.g. migraine with aura) and cervical artery dissection published through October 2010.

Results: We identified five case-control studies investigating the association between migraine and cervical artery dissection. In pooled analysis, migraine doubled the risk of cervical artery dissection (pooled odds ratio [OR] = 2.06, 95% confidence interval [CI] 1.33–3.19). All studies allowed evaluation of migraine aura status. While the effect estimate for migraine without aura (pooled OR = 1.94, 95% CI 1.21–3.10) was similar to overall migraine, the association was weaker for migraine with aura (pooled OR = 1.50, 95% CI 0.76–2.96). However, there is no evidence that aura status significantly modifies the association between migraine and cervical artery dissection (meta-regression on aura status p = .58). The risk does not appear to differ between women and men; however, only few studies presented gender-specific data. Heterogeneity among studies was low to moderate.

Conclusion: In this meta-analysis migraine is associated with a two-fold increased risk of cervical artery dissection. This risk does not appear to significantly differ by migraine aura status or gender.
Increased risk of stroke after trigeminal neuralgia – a population-based follow-up study
Authors: Pan Shin-Liang , Chen Li-Sheng , Yen Ming-Fang , Chiu Yueh-Hsia , Chen Hsiu-Hsi
Published: April 2011

Background: There are no reports on the risk of stroke after trigeminal neuralgia (TN). The aim of this population-based follow-up study was to investigate whether the occurrence of TN is associated with a higher risk of developing stroke.

Methods: A total of 1453 people with at least three ambulatory visits in 2001 with the principal diagnosis of TN were enrolled in the TN cohort. The non-TN cohort consisted of 5812 age- and sex-matched, randomly sampled subjects without TN. The 2-year stroke-free survival rate between the two groups was compared using the Kaplan-Meier method. The Cox proportional hazards regression model was used to estimate the hazard ratio of stroke after adjustment for demographic and clinical covariates.

Results: In the TN cohort, 73 patients developed stroke during follow-up, while in the non-TN cohort, 157 subjects suffered a stroke. The crude hazard ratio of stroke for the subjects with TN was 1.86 (95% CI, 1.41–2.45; p < 0.0001). The adjusted hazard ratio was 1.76 (95% CI, 1.33–2.33; p < 0.0001) after adjusting for demographic characteristics and comorbid medical disorders.

Conclusion: This study showed a significantly increased risk of developing stroke after TN. Further studies are needed to investigate the underlying mechanism of this association.
Spinal manipulations for the treatment of migraine: A systematic review of randomized clinical trials
Authors: Posadzki P , Ernst E
Published: April 2011

Aims: The objective of this systematic review was to assess the effectiveness of spinal manipulations as a treatment for migraine headaches.

Method: Seven databases were searched from inception to November 2010. All randomized clinical trials (RCTs) investigating spinal manipulations performed by any type of healthcare professional for treating migraine headaches in human subjects were considered. The selection of studies, data extraction and validation were performed independently by two reviewers.

Results: Three RCTs met the inclusion criteria. Their methodological quality was mostly poor and ranged between 1 and 3 on the Jadad scale. Two RCTs suggested no effect of spinal manipulations in terms of Headache Index or migraine duration and disability compared with drug therapy, spinal manipulation plus drug therapy, or mobilization. One RCT showed significant improvements in migraine frequency, intensity, duration and disability associated with migraine compared with detuned interferential therapy. The most rigorous RCT demonstrated no effect of chiropractic spinal manipulation compared with mobilization or spinal manipulation by medical practitioner or physiotherapist on migraine duration or disability.

Conclusions: Current evidence does not support the use of spinal manipulations for the treatment for migraine headaches.
Protective effects of zinc and selenium against benzene toxicity in rats
Authors: Ibrahim Khadiga S , Saleh Zeinab A , Farrag Abdel-Razik H , Shaban Eman E
Published: April 2011

The presented study investigates the protective role of zinc (Zn) and selenium (Se) in attenuating benzene-induced toxicity in rats. Male Sprague—Dawley rats were injected with benzene (0.5 mL/kg body weight ip) and received a diet supplement containing Zn and Se. Several hematological and biochemical parameters (representing antioxidant status) were estimated. Histopathological examinations were performed. Results showed that food intake and body weight gain of benzene-injected rats were significantly lower than that of the control rats. Benzene-injected rats showed increased plasma malondialdehyde (MDA) and decreased activity of: glutathione peroxidase (GSH-Px), catalase, superoxide dismutase (SOD) enzymes, as well as reduced glutathione (GSH) when compared to the control group. Histopathological investigations revealed structural changes in benzene-injected rats’ liver. Supplementation with Zn and Se resulted in a significant decrease in MDA, elevation in GSH, GSH-Px, SOD and catalase levels. This study shows that Zn and Se supplementation can improve the activity of antioxidant enzymes in rats and decrease the histological anomalies induced by benzene toxicity as well.
Elaidic acid enhanced the simultaneous neurotoxicity attributable to the cerebral pathological lesion resulted from oxidative damages induced by acrylamide and benzo(a)pyrene
Authors: Zhang MA , Chen FH , Huang ZY , Zhang XC
Published: April 2011

Acrylamide (ACR), benzopyrene [B(a)P] and trans-fatty acids (TFA) could be found to co-exist in many foods processed by high temperature. Our study investigated the effects of elaidic acid (ELA), a predominant TFA, on neuropathology induced by simultaneous exposure of ACR and B(a)P to mice. Results showed ELA enhanced the decrease of weight gains induced by simultaneous exposure of ACR and B(a)P (AB). Moreover, ELA enhanced ACR-induced increase of gait abnormality, B(a)P-induced damage to learning and memory, and AB-induced both of the damage above. Meanwhile, ELA enhanced B(a)Pinduced axonal degeneration in hippocamp, ACR- and AB-induced up-regulating of abnormal cerebellar Purkinje cells. ELA enhanced ACR-induced up-regulating of MDA in cerebrum and 8-OHdG in cerebrum and cerebellum; ELA enhanced B(a)P-induced up-regulating of MDA in cerebrum, PCO in cerebellum and 8-OHdG in cerebrum and cerebellum. Meanwhile, the enhancing role of ELA, on ACR-induced reduction of SOD activity in cerebrum and cerebellum, on B(a)P-induced reduction of GPx activity in cerebrum were found. Results suggested that ELA play a enhancing role on ACR-induced and B(a)P-induced oxidative damage, which attributable to the cerebral pathological lesion, and subsequent effect on gait abnormality and deficit on learning and memory in mice.
Anti-oxidative and anti-genotoxic effects of methanolic extract of Mentha pulegium on human lympocyte culture
Authors: Alpsoy Lokman , Şahin Hilal , Karaman Şeyda
Published: April 2011

In the present work, methanolic extract of Mentha pulegium from Erzurum, Turkey, was used in order to report the results of anti-oxidant capacity, anti-oxidant activity and anti-genotoxic effects. The total antioxidant capacity and total phenolic content were measured by using CUPRAC, ABTS and Folin—Ciocalteu colorimetric methods. The total phenolic content was higher than the total antioxidant capacity (for the results of both the CUPRAC and ABTS methods) of methanolic extract of M pulegium (ME). Also, we evaluated the anti-oxidant enzyme activity such as superoxide dismutase (SOD) and glutation peroxidase, total glutation (GSH) and malondialdehyde (MDA) in human lymphocyte culture. In CCI4-treated group, the activity of SOD, glutathione peroxidase (GPx) and GSH decreased significantly and the level of MDA increased significantly. A significant increase in the activity of SOD, GPx and the level of GSH were seen when supplemented with ME to CCI4-treated group. Furthermore, a significant decrease in the level of MDA was observed when compared with CCI4 alone treated group. In addition, anti-genotoxic effect of ME was studied by using sister chromatid exchange (SCE) method. As a result, ME has shown anti-genotoxic effect depend on anti-oxidative effect on human lymphocyte culture.
Hippocampal neuron number loss in rats exposed to ingested sulfite
Authors: Akdogan Ilgaz , Kocamaz Erdogan , Kucukatay Vural , Yonguc Nilufer Goksin , Ozdemir Mehmet Bulent , Murk William
Published: April 2011

Sulfite, which is continuously formed in the body during metabolism of sulfur-containing amino acids, is commonly used in preservatives. It has been shown that there are toxic effects of sulfite on many cellular components. The aim of this study was to investigate the possible toxic effects of sulfite on pyramidal neurons by counting cell numbers in CA1 and CA2-CA3 subdivisions of the rat hippocampus. For this purpose, male albino rats were divided into a control group and a sulfite group (25 mg/kg). Sulfite was administered to the animals via drinking water for 8 weeks. At the end of the experimental period, brains were removed and neurons were estimated in total and in a known fraction of CA1 and CA2-CA3 subdivisions of the left hippocampus by using the optical fractionator method—a stereological method. Results showed that sulfite treatment caused a significant decrease in the total number of pyramidal neurons in three subdivisions of the hippocampus (CA1 and CA2-CA3) in the sulfite group compared with the control group (p < 0.05, Mann Whitney U test). It was concluded that exogenous administration of sulfite causes loss of pyramidal neurons in CA1 and CA2-CA3 subdivisions of the rat hippocampus.
Effects of two plant growth regulators, indole-3-acetic acid and β-naphthoxyacetic acid, on genotoxicity in Drosophila SMART assay and on proliferation and viability of HEK293 cells from the perspective of carcinogenesis
Authors: Karadeniz Asuman , Kaya Bülent , Savaş Burhan , Topcuoğlu Ş. Fatih
Published: April 2011

In this study, the mutagenic and recombinogenic effects of indole-3-acetic acid (IAA), a plant growth regulator naturally synthesized in plants but produced synthetically, and β-naphthoxyacetic acid (BNOA), a synthetic plant growth regulator widely used in agricultural regions, were investigated using the somatic mutation and recombination test (SMART) in Drosophila wings. The effect of the same plant growth regulators against the proliferation and viability of a human immortalized embryonic kidney HEK293 cells which is at the early stage of carcinogenesis were also examined with MTT and trypan-blue exclusion assays. For the SMART assay, two different crosses were used: a standard and a high-bioactivation (HB) cross, involving the flare-3 and the multiple wing hairs markers. The HB cross involved flies characterized by an increased cytochrome P-450-dependent bioactivation capacity, which permits the more efficient biotransformation of promutagens and procarcinogens. In both crosses, the wings of the two types of progeny, inversion-free marker heterozygotes and balancer heterozygotes, were analyzed. The results show that IAA and BNOA are not mutagenic or recombinogenic in the wing cells of Drosophila. Furthermore, neither plant growth regulator affected the proliferation rate of HEK293 cells; however, both of them induced cell death at high concentrations.
Protective effect of chrysin on carbon tetrachloride (CCl4)—induced tissue injury in male Wistar rats
Authors: Anand Kalaiselvi Velayutham , Anandhi Ramalingam , Pakkiyaraj Murugesan , Geraldine Pitchairaj
Published: April 2011

Chrysin, a natural flavonoid has been reported to possess potent anti-inflammatory, anti-cancer and antioxidation properties. In the present study, we aimed to evaluate the putative protective effect of chrysin, an isoflavone, on carbon tetrachloride (CCl4)-induced toxicity in male Wistar rats. Intraperitoneal administration of CCl4 (2 ml/kg) to rats for 4 days resulted in significantly elevated ( p < 0.05) serum levels of glutamic oxaloacetic transaminase (SGOT), glutamic pyruvate transaminase (SGPT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH), when compared to normal rats. In addition, the tissues (liver, kidney and brain) and haemolysate samples showed considerable increase in levels ( p < 0.05) of malondialdehyde (MDA) and lowered levels ( p < 0.05) of reduced glutathione (GSH), vitamin C and E when compared to values in normal rats. Quantitative analysis of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (Gpx) exhibited lower activities of these antioxidant enzymes in the tissues and haemolysate of CCl4-administered rats. The protective action of chrysin on CCl4-induced rat was demonstrated with SGPT, SGOT, ALP and LDH resuming to near normal levels, while the mean levels of GSH and of vitamin C and E were elevated, the mean activities of CAT, SOD and Gpx were enhanced and the mean level of MDA was lowered in the tissue and haemolysate samples when compared to the CCl4-exposed untreated rats. The expression of the iNOS gene appeared to be up-regulated in the liver and kidney samples of CCl4-exposed untreated rats, whereas in CCl4-exposed chrysin-treated rats, the mRNA transcript levels of iNOS approximated normal levels. These results strongly suggest that chrysin is able to prevent the oxidative damage induced by CCl4 in the liver, brain, kidney and haemolysate of male Wistar rats.
The Process of Healing Transformations
Authors: Rosa Katherine Cowen
Published: April 2011

This article presents an emerging model of healing transformations to guide nurses in caring for those living with a chronic illness. A review of the literature on chronic illness and its relationship to lifestyle behavior change and transformative nursing practice is included. Derived from qualitative narratives, this work reports the clusters of phenomena within each phase of the model. The model emerged from data gathered during 36 in-depth interviews with 18 men and women living with chronic skin wounds. During two interviews, each participant shared important life stories and meaningful reflections on living with a chronic skin wound. Using the theory of health as expanding consciousness, analysis of each participant’s life story revealed individual life patterns and patterns across participants. These patterns were validated and reflected on with participants during the second interview. Synthesizing participants’ patterns of responses, the model of healing transformations emerged. Developed from clients’ experiences, the model of healing transformations provides rich insight into the nature of healing and the central role of the nurse practicing from a holistic perspective in this process. Nurses make a positive difference in the healing trajectory of those living with chronic illnesses such as chronic skin wounds.
Human versus climatic influences on late-Holocene fire regimes in southwestern Nicaragua
Authors: Avnery Shiri , Dull Robert A. , Keitt Timothy H.
Published: April 2011

Fire regimes in the lowland Neotropics are affected both by anthropogenic land use practices and natural climate variability. In Central America it is widely recognized that fire has been used as an agricultural tool for thousands of years, but the role of anthropogenic ignition as a determinant of past biomass burning frequency and magnitude has been debated. Little is known about the effects of short-term climate variability on fire regimes in this region of the world because of both the low temporal resolution of the available charcoal records and the obfuscating effects of anthropogenic burning throughout the late Holocene. Here we reconstruct 1400 years of fire history and environmental change on Ometepe Island, Lake Nicaragua, and perform statistical wavelet analysis on multiple proxy records to identify natural cycles of environmental variability possibly related to climate forcing. Our results indicate that extensive indigenous burning and landscape modification largely mask any climate signal in the paleo-fire record from AD 580 to 1400, with the exception of the period AD 775—1000 where high wavelet power exists at scales of 2—24 years. This time period coincides with a severe, two-century long regional drought that has been identified at other locations in Central America. High wavelet power at climate-relevant scales after ~AD 1400 in the Ometepe fire record suggests that periodic drought possibly caused by the El Niño Southern Oscillation and/or high-frequency solar cycles may have played a significant role in influencing the post-contact fire regime — a role that is largely concealed in the pre-European strata because of the overriding effects of anthropogenic burning.
Palaeoenvironmental signals in ancient urban setting: The heavy rainfall record in Sumhuram, a pre-Islamic archaeological site of Dhofar (S Oman)
Authors: Lippi Marta Mariotti , Bellini Cristina , Benvenuti Marco , Fedi Mariaelena
Published: April 2011

A case study of an archaeological section in the pre-Islamic town of Sumhuram (third century bc–fifth century ad; Dhofar, S Oman) is presented. Sedimentological and palynological data have been integrated with the aim of finding signals of natural processes within an urban context. Two main types of deposits alternate in the section: anthropogenic (AD) and waterlain (WD). The presence of laminated sediments within the WD deposits, suggesting short-term street flooding from heavy rainfall, encouraged the development of a targeted palynological sampling strategy. The results of the pollen analysis in these laminated sediments, e.g. high pollen concentrations (particularly of wet environment plants), clumped pollen grains, long distance pollen grains, and overall good state of preservation, suggest a stronger monsoonal influence than the present and high precipitation in S Oman between 204 bc and ad 130.