bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of the innate and adaptive immunity in type I and type II focal cortical dysplasias
Authors: Iyer Anand , Zurolo Emanuele , Spliet Wim G.M. , Van Rijen Peter C. , Baayen Johannes C. , Gorter Jan A. , Aronica Eleonora
Published: March 2010

Purpose:  Induction of inflammatory pathways has been reported in epileptic patients with focal malformations of cortical development. In the present study we examined the innate and adaptive immune responses in focal cortical dysplasia (FCD) with different histopathologic and pathogenetic features.

Methods:  The inflammatory cell components and the induction of major proinflammatory pathways and molecules [complement pathway, interleukin (IL)‐1β, and chemokine monocyte chemotactic protein‐1 (MCP1)] was investigated in surgical specimens of sporadic type IA and type IIB FCD using immunocytochemical methods.

Results:  FCD II but not FCD I cases exhibit activation of the mammalian target of rapamycin (mTOR) cascade with strong neuronal expression of the phosphorylated isoform of S6 protein. Microglia reactivity was increased in all lesions (FCD I and II) compared to control tissue; however, the number of HLA‐DR–positive cells was significantly higher in FCD II than in FCD I. In FCD II specimens we also observed perivascular and parenchymal T lymphocytes (CD3+), with a predominance of CD8+ T‐cytotoxic/suppressor lymphocytes, as well as a few dendritic cells. Expression of components of the complement cascade, IL‐1β, and MCP1 was prominent in FCD II cases.

Discussion:  Our findings indicate a prominent activation of both innate and adaptive immunity, with involvement of different inflammatory pathways in FCD II cases, supporting the possible involvement of inflammation in the epileptogenesis of these lesions, as well as the notion that FCD II is pathologically distinct from FCD I.
Predicting Well‐Being Among Ethnic Minorities: Psychological Empowerment and Group Identity
Authors: Molix Lisa , Bettencourt B. Ann
Published: March 2010

Two studies examine the impact of individual differences in group identity on psychological empowerment and well‐being among members of the ethnic minority and majority. Study 1 revealed an interaction between ethnicity and group identity in predicting empowerment and well‐being. Moreover, the results revealed that psychological empowerment partially mediated the relationship between group identity and well‐being among ethnic minorities. Using a mini‐longitudinal design, the results of Study 2 revealed interactions between ethnicity and group identity at Time 1 predicting psychological empowerment, well‐being, and positive affect at Time 2. In addition, the results confirmed psychological empowerment at Time 2 as a mediator of the relationship between group identity at Time 1 and well‐being at Time 2.
The Scientific Impotence Excuse: Discounting Belief‐Threatening Scientific Abstracts
Authors: Munro Geoffrey D.
Published: March 2010

The scientific impotence discounting hypothesis predicts that people resist belief‐disconfirming scientific evidence by concluding that the topic of study is not amenable to scientific investigation. In 2 studies, participants read a series of brief abstracts that either confirmed or disconfirmed their existing beliefs about a stereotype associated with homosexuality. Relative to those reading belief‐confirming evidence, participants reading belief‐disconfirming evidence indicated more belief that the topic could not be studied scientifically and more belief that a series of other unrelated topics could not be studied scientifically. Thus, being presented with belief‐disconfirming scientific evidence may lead to an erosion of belief in the efficacy of scientific methods.
The Objective Value of Subjective Value: A Multi‐Round Negotiation Study
Authors: Curhan Jared R. , Elfenbein Hillary Anger , Eisenkraft Noah
Published: March 2010

A 2‐round negotiation study provided evidence that positive feelings resulting from one negotiation can be economically rewarding in a second negotiation. Negotiators experiencing greater subjective value (SV)—that is, social, perceptual, and emotional outcomes from a negotiation—in Round 1 achieved greater individual and joint objective negotiation performance in Round 2, even with Round 1 economic outcomes controlled. Moreover, Round 1 SV predicted the desire to negotiate again with the same counterpart, whereas objective negotiation performance had no such association. Taken together, the results suggest that positive feelings, not just positive outcomes, can evoke future economic success.
The Power of Positive Recollections: Reducing Test Anxiety and Enhancing College Student Efficacy and Performance
Authors: Nelson Donna Webster , Knight Ashley E.
Published: March 2010

This research sought to develop an intervention (targeting positive emotions and thoughts) as a mechanism for reducing test anxiety and raising confidence and performance in a sample of college students. Participants were randomly assigned to a positive thought task or a control task. Those in the positive‐thought condition, who were assigned to write about successful personal experiences, derived several benefits, when compared with control participants who wrote about their morning routines. Specifically, they experienced more positive affect and less negative affect, exhibited a more optimistic outlook, and reported less test anxiety. They were more likely to appraise the quiz confidently, perceiving it as a challenge rather than a threat. Perhaps most importantly, they exhibited superior performance on the quiz.
Increased expression of APAF‐1 in low‐risk myelodysplastic syndrome: a possible role in the pathophysiology of myelodysplasia
Authors: Benites Bruno Deltreggia , Traina Fabiola , Duarte Adriana da Silva Santos , Lorand‐Metze Irene Gyongyver H. , Costa Fernando Ferreira , Saad Sara Teresinha
Published: March 2010

Objectives: APAF‐1 is a central component of the intrinsic pathway of apoptosis, where APAF‐1 dysregulation results in the development of diverse human neoplasms. The aim of this study was to characterize the mRNA expression levels of APAF‐1 transcripts in low‐risk and high‐risk MDS and to elucidate whether the expression levels of APAF‐1 transcripts are modulated with increased apoptosis in CD34+ MDS cells undergoing erythroid differentiation. Methods: APAF‐1 (NM_181861) expression was verified, by quantitative RT‐PCR, in bone marrow aspirates from 33 patients with myelodysplastic syndromes (MDS), at the time of diagnosis, and in erythroid differentiation cultures from CD34+ from normal donors and patients with MDS. Results: APAF‐1 expression was significantly higher in low‐risk, compared to high‐risk MDS, according to IPSS (P < 0.0001), FAB (P = 0.0265), and cytogenetic risk (P = 0.0134). Low‐risk MDS‐derived differentiated erythroid cells demonstrated an increased expression of APAF‐1, compared with normal cells, accompanied by an augmented rate of apoptosis. Conclusions: Increased expression of APAF‐1 in low‐risk disease and its positive correlation with the apoptotic rate observed during the erythroblast differentiation of low‐risk MDS cells may indicate that the modulation of APAF‐1, at the transcriptional level, participates in the pathophysiology of MDS.
APPLICATION OF ARTIFICIAL NEURAL NETWORKS TO PREDICT CLOSTRIDIUM BOTULINUM GROWTH AS A FUNCTION OF ZATARIA MULTIFLORA ESSENTIAL OIL, pH, NaCl AND TEMPERATURE
Authors: KHANZADI SAEID , GHARIBZADEH SHAHRIAR , RAOUFY MOHAMMAD REZA , RAZAVILAR VADUD , KHAKSAR RAMIN , RADMEHR BEHRAD
Published: March 2010

The present study is undertaken to predict the effects of Zataria multflora essential oil, NaCl, temperature and pH on the probability percentage of growth of Clostridium botulinum using artificial neural network (ANN).

To assess the effects of essential oil, NaCl, pH and temperature on Log P% of C. botulinum type A spores, the experiment was arranged in a factorial design. This design (4 × 3 × 3 × 3) included four levels of EO (0.0, 0.015, 0.03 and 0.06%), three levels of NaCl (0.5, 4 and 6%), three levels of pH (6, 6.5 and 7.4), three storage temperatures (15, 25 and 35C) and repeated observations (12 times) for growth in BHI broth for up to 43 days (D).

According to our results, the log P% of C. botulinum was affected significantly (P < 0.01) by Essential oil, pH, NaCl and temperature.

The numbers of neurons in input hidden and output layers were 5, 11 and 1, respectively.

The inputs to the ANN were temperature, pH, NaCl, essential oil and the number of days after inoculation. The output of the ANN was log P%.

Our results show that the ANN is a suitable model for predicting the growth of C. botulinum when it is affected by different levels of pH, temperature, NaCl and essential oil.

PRACTICAL APPLICATIONS

Clostridium botulinum is an anaerobic bacterium that produces a powerful neurotoxin. Because there is concern over the safety of some chemical preservatives, an increased interest is started into more natural alternatives. Zataria multiflora has been used traditionally as flavor agent and its antimicrobial activities has been established in previous studies. In addition, predictive food microbiology involves the knowledge of microbial growth responses to environmental factors summarized as mathematical models. Over the last few years, artificial neural networks (ANNs), as nonlinear modeling techniques, have been proposed for use in predictive microbiology. Considering the importance of C. botulinum and using natural preservative in food safety and the power of ANN in predicting purposes, we suggest that ANN can be used as a prediction tool in food safety.
ISOLATION AND IDENTIFICATION OF SALMONELLA ENTERITIDIS AND SALMONELLA TYPHIMURIUM FROM THE EGGS OF RETAIL STORES IN MASHHAD, IRAN USING CONVENTIONAL CULTURE METHOD AND MULTIPLEX PCR ASSAY
Authors: JAMSHIDI A. , KALIDARI G.A. , HEDAYATI M.
Published: March 2010

In this study, a total of 250 eggs were collected randomly from 50 retail stores in Mashhad city over a period of 3 months in the summer of 2008. Five samples from each store were collected, and transferred to the laboratory. In order to isolate Salmonella spp., conventional culture method – including pre‐enrichment, enrichment, selective plating and differential plating – were performed. To confirm the identification of isolated colonies as Salmonella spp. and determining serovars as Typhimurium and Enteritidis serovars, a multiplex polymerase chain reaction assay using three pairs of primers were employed: S141 and S139 for the invA gene, specific for the genus of Salmonella; Fli15 and Tym for the fliC gene, specific for Typhimurium serovar; and Prot6e‐5 and Prot6e‐6 for Prot6E gene, specific for Enteritidis serovar. Four out of 250 samples (1.6%) from eggshells were determined as contaminated with Salmonella spp. Isolated colonies were confirmed as Salmonella, and their serovar was determined as Typhimurium. Salmonella spp. was not isolated from the eggs' contents.

PRACTICAL APPLICATIONS

It seems that Salmonella Typhimurium is the most prevalent serotype of egg contaminant in the Mashhad area of Iran, and the multiplex polymerase chain reaction method based on amplification from conserved genes could be a reliable alternative for conventional culture methods.
STUDIES ON ENTEROTOXIGENIC BACILLUS CEREUS IN RAW MILK AND SOME DAIRY PRODUCTS
Authors: HASSAN G.M. , AL‐ASHMAWY M.A.M. , MESHREF A.M.S. , AFIFY S.I.
Published: March 2010

A total of 150 samples of raw milk, ice cream and yogurt (50 of each) were collected randomly in their packages from different localities in Beni‐Suef governorate, Egypt, to study the presence of Bacillus cereus in these products. B. cereus could be detected in 30, 48 and 2% of examined raw milk, ice cream and yogurt samples with a mean count of 9.11 × 102 ± 4.87 × 102, 6.37 × 103 ± 2.83 × 103 and 6 ± 5.9 cells/mL or g, respectively. All B. cereus isolates showed hemolytic activity; 95% of isolates showed vero cell toxicity and 27.5% of them killed adult mice. B. cereus could not be detected in artificially inoculated yogurt after 24 and 48 h. B. cereus was sensitive to pefloxacin, gentamycin, chloramphenicol and nalidixic acid, whereas all isolates were resistant to colistin sulfate. Public health significance and suggestive control measures are discussed.

PRACTICAL APPLICATIONS

The incidence of contamination of raw milk and ice cream by Bacillus cereus is fairly high, and nearly all of the isolates showed hemolysin and cytotoxic toxin activities, so the risk of food poisoning caused by B. cereus in such products should not be neglected. B. cereus rapidly dies in yogurt, so acidification is a common method of preservation, and as the acidity of fermented milk increased, B. cereus fails to survive. Pefloxacin, gentamicin and chloramphenicol are effective antibiotics against B. cereus infection. B. cereus is highly resistant to colistin sulfate.
The analysis of JAK2 and MPL mutations and JAK2 single nucleotide polymorphisms in MPN patients by MassARRAY assay
Authors: ZHANG S.‐J. , QIU H.‐X. , LI J.‐Y. , SHI J.‐Y. , XU W.
Published: March 2010

Recent studies have shown that JAK2 V617F, MPL W515L/K and JAK2 exon 12 mutations underlie the major molecular pathogenesis of myeloproliferative disorders (MPN). Allele‐Specific Polymerase Chain Reaction (AS‐PCR), direct sequencing and MassARRAY assay were used to ascertain the real prevalence of these mutations and the influence of genetic susceptibility in Chinese MPN patients. The positive rate of JAK2 V617F in polycythaemia vera (PV), essential thrombocythaemia (ET) and primary myelofibrosis (PMF) was 82.0%, 36.6% and 51.1% respectively. One ET patient and two PMF patients harboured the MPL W515L mutation and three PV patients harboured JAK2 exon 12 mutations. All of these patients were confirmed as JAK2 V617F negative. Clinical data demonstrated that PV patients with JAK2 exon 12 mutations were younger, had higher haemoglobin levels and white blood cell counts than PV patients with JAK2 V617F. In addition, through analysis of 4 polymorphic loci of JAK2 gene, no significant difference of distribution frequency was found among PV, ET and PMF patients. Distribution frequency of haplotype also was not significantly different among PV, ET and PMF patients. We conclude that JAK2 V617F is a major molecular pathogenesis in Chinese MPN patients. MPL W515L mutation and JAK2 exon 12 mutations can also be found in JAK2 V617F negative MPN patients.
Moderation of Success and Failure Feedback by Validation Seeking on Affect Change: Implications for Theories of Cognitive Adaptation and Self‐Worth Regulation
Authors: Horvath Peter , Wambolt Pamela
Published: March 2010

The present study examined validation seeking as a form of cognitive adaptation and self‐worth regulation. A total of 88 undergraduates completed questionnaires on validation seeking and affect, a sequence task, and randomly received positive, negative, or neutral feedback on their performance. Validation seeking was associated with anxiety and dysphoria. It also moderated negative feedback to increase dysphoria and positive feedback to increase positive affect and decrease anxiety at posttest. The findings were compatible with the proposition that validation seeking can have positive coping aspects in certain circumstances, and can be more generally conceptualized as a form of cognitive adaptation. The findings extend our understanding of how components in cognitive adaptation and self‐regulation facilitate well‐being.
From Intentions to Quit to the Actual Quitting Process: The Case of Smoking Behavior in Light of the TPB
Authors: Kovač Velibor Bobo , Rise Jostein , Moan Inger Synnøve
Published: March 2010

The purpose of the present paper was to examine the path from intentions to quit smoking to the actual quitting process in light of the theory of planned behavior. Data derives from a longitudinal internet survey (N = 939) over a period of 4 months. Attitudes, subjective norms, perceived behavioral control (PBC), and past behavior emerged as significant direct predictors of quitting intention (R2 = 34%). Ordinal regression analysis showed that intention, PBC, planning, past quit attempts and habit were significant predictors of the subsequent quitting process. Consistent with previous research the results show that addicted individuals have serious problems in sticking to their initial plans. Theoretical and practical implications of the results are discussed.
Permanent Genetic Resources added to Molecular Ecology Resources Database 1 December 2009–31 January 2010
Authors:   Molecular Ecology Resources Primer Development Consortium, ANDERSON CYNTHIA M. , APARICIO GALLEGO J. , ATANGANA ALAIN R. , BEAULIEU JEAN , BRUFORD M.W. , CAIN FORREST , CAMPOS T. , CARIANI A. , CARVALHO M.A. , CHEN NAN , CHEN P.P. , CLAMENS A.‐L. , CLARK ANN M. , COEUR D’ACIER A. , CONNOLLY PAUL , CORDERO‐RIVERA ADOLFO , COUGHLAN JAMES P. , CROSS THOMAS S. , DAVID BRUNO , DE BRUYN COLIN , DE MEYER M. , DE RIDDER CHANTAL , DELATTE H. , DETTORI M.T. , DOWNER S.J. , DUBREUIL CHRISTINE , EVANS K.J. , FAN BIN , FERRARA G. , GAGNÉ ANDRÉ , GAILLARD MARIA , GIGLIARELLI L. , GIOVINAZZI J. , GOMEZ D.R. , GRÜNWALD N.J. , HANSSON BENGT , HUOTARI T. , JANK L. , JOUSSELIN E. , JUNGMANN L. , KACZMAREK M.E. , KHASA DAMASE P. , KNEEBONE JEFF , KORPELAINEN H. , KOSTAMO K. , LANFALONI L. , LIN HAORAN , LIU XIAOCHUN , LUCENTINI L. , MAES G.E. , MAHAFFEE W.F. , MENG ZINING , MICALI S. , MILANO I. , MOK H.F. , MORIN L. , NEILL T.M. , NEWTON CRAIG H. , GIGI OSTROW D. , PALOMBA A. , PANARA F. , PULETTI M.E. , QUARTA R. , QUILICI S. , RAMOS A.K.B. , RIGAUD THIERRY , RISTERUCCI A.M. , SALOMON MATTHEW P. , SÁNCHEZ‐GUILLÉN ROSA A. , SARVER SHANE K. , SEQUEIRA A.S. , SFORÇA D.A. , SIMIAND C. , SMITH BRIAN , SOUSA A.C.B. , SOUZA A.P. , STEPIEN C.C. , STUCKERT A.J. , SULIKOWSKI JAMES , TAYEH A. , TINTI F. , TSANG PAUL C.W. , VAN HOUDT J.K.J. , VENDRAMIN E. , VERDE I. , VIRGILIO M. , WANG HUAN L. , WANG LE , WATTIER RÉMI A. , WELLENREUTHER MAREN , XIE CONG X. , ZANE L. , ZHANG XIU J. , ZHANG YONG , ZHUANG ZHIMENG , ZUCCHI M.I.
Published: March 2010

This article documents the addition of 220 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Allanblackia floribunda, Amblyraja radiata, Bactrocera cucurbitae, Brachycaudus helichrysi, Calopogonium mucunoides, Dissodactylus primitivus, Elodea canadensis, Ephydatia fluviatilis, Galapaganus howdenae howdenae, Hoplostethus atlanticus, Ischnura elegans, Larimichthys polyactis, Opheodrys vernalis, Pelteobagrus fulvidraco, Phragmidium violaceum, Pistacia vera, and Thunnus thynnus. These loci were cross‐tested on the following species: Allanblackia gabonensis, Allanblackia stanerana, Neoceratitis cyanescens, Dacus ciliatus, Dacus demmerezi, Bactrocera zonata, Ceratitis capitata, Ceratitis rosa, Ceratits catoirii, Dacus punctatifrons, Ephydatia mülleri, Spongilla lacustris, Geodia cydonium, Axinella sp., Ischnura graellsii, Ischnura ramburii, Ischnura pumilio, Pistacia integerrima and Pistacia terebinthus.
A new environment for aerobic anoxygenic phototrophic bacteria: biological soil crusts
Authors: Csotonyi Julius T. , Swiderski Jolantha , Stackebrandt Erko , Yurkov Vladimir
Published: March 2010

Phototrophic microorganisms are critical to the carbon cycling and productivity of biological soil crusts, which enhance water content, nutrient relations and mechanical stability of arid soils. Only oxygen‐producing phototrophs, including cyanobacteria and algae, are known from soil crusts, but Earth's second major branch of photosynthetic organisms, the evolutionarily earlier anoxygenic phototrophs, is unreported. We announce the discovery of aerobic anoxygenic phototrophs in three Canadian soil crust communities. We found in a culture‐based study that they comprised 0.1–5.9% of the cultivable bacterial community in moss‐, lichen‐ and cyanobacteria‐dominated crust from sand dunes and sandy soils. Comparable in density to aerobic phototrophs in other habitats, the bacteriochlorophyll a‐possessing pink and orange isolates were related to species of Methylobacterium (99.0–99.5%), Belnapia (97.4–98.8%), Muricoccus (94.4%) and Sphingomonas (96.6–98.5%), based on 16S rRNA gene sequences. Our results demonstrate that proteobacterial anoxygenic phototrophs may be found in dry soil environments, implying desiccation resistance as yet unreported for this group. By utilizing sunlight for part of their energy needs, aerobic phototrophs can accelerate organic carbon cycling in nutrient‐poor arid soils. Their effects will be especially important as global climate change enhances soil erosion and consequent nutrient loss.
Enhanced biodegradation of petroleum hydrocarbons in the mycorrhizosphere of sub‐boreal forest soils
Authors: Robertson Susan J. , Kennedy Nabla M. , Massicotte Hugues B. , Rutherford P. Michael
Published: March 2010

Petroleum hydrocarbon (PHC) contamination is becoming more common in boreal forest soils. However, linkages between PHC biodegradation and microbial community dynamics in the mycorrhizosphere of boreal forest soils are poorly understood. Seedlings (lodgepole pine, paper birch, lingonberry) were established in reconstructed soil systems, consisting of an organic layer (mor humus, coarse woody debris, or previously oil‐contaminated mor humus) overlying mineral (Ae, Bf) horizons. Light crude oil was applied to the soil surface after 4 months; systems were destructively sampled at 1 and 16 weeks following treatment. Soil concentrations of four PHC fractions were determined using acetone–hexane extraction followed by gas chromatography – flame ionization detection analysis. Genotypic profiles of root‐associated bacterial communities were generated using length heterogeneity‐PCR of 16S rDNA. Most plant–soil treatments showed significant loss in the smaller fraction PHCs indicating an inherent capacity for biodegradation. Concentrations of total PHCs declined significantly only in planted (pine‐woody debris and birch‐humus) systems (averaging 59% and 82% loss between 1 and 16 weeks respectively), reinforcing the importance of the mycorrhizosphere for enhancing microbial catabolism. Bacterial community structure was correlated more with mycorrhizosphere type and complexity than with PHC contamination. However, results suggest that communities in PHC‐contaminated and pristine soils may become distinct over time.
Performance Audit of the Operational Stage of Long‐Term Partnerships for the Private Sector Provision of Public Services
Authors: English Linda M. , Guthrie James , Broadbent Jane , Laughlin Richard
Published: March 2010

This study investigates the challenges associated with designing a system to evaluate the mature operating phase of long‐term partnerships with the private sector for the provision of public services (PPPS), an area largely neglected by a performance audit (PA) focus. It argues that assessing economy, efficiency and effectiveness (the three Es) are key to any PA, but that their nature is contextually defined; that auditing for effectiveness involves going beyond a ‘watchdog’ to a ‘sheepdog’ role; and that internal evaluation procedures provide insights that are necessary, but not necessary and sufficient to evaluating the achievement of the three Es in the PPPS mature operating stage. Findings are based on an analysis of the literature and an engagement with an audit office. The paper elucidates the meaning of each of the three Es in the context of PA of the PPPS mature operating stage.
Producing Spaces for Academic Discourse: The Impact of Research Assessment Exercises and Journal Quality Rankings
Authors: Northcott Deryl , Linacre Simon
Published: March 2010

This study examines the impact of national research assessment exercises (NRAEs) and associated journal quality rankings on the development, scope and sustainability of the academic journals in which accounting research is disseminated. The reported exploratory study focused on the United Kingdom (UK), Australia and New Zealand as three countries in which NRAEs are well developed or imminent. Data were collected via a survey of authors, interviews with journal editors, and feedback from publishers responsible for producing academic accounting journals.

The findings suggest that, despite cynicism around the reliability of published journal quality rankings, the entrenchment of NRAE ‘rules’ and journal quality perceptions has changed authors’ submission choices and left lower ranked journals struggling with a diminished quantity and quality of submissions. A clear perception is that NRAEs have done little to improve the overall quality of the accounting literature, but are impeding the diversity, originality and practical relevance of accounting research.

Although strategies are suggested for meeting these challenges, they require strategic partnerships with publishers to enhance the profile and distribution of emerging journals, and depend on the willingness of accounting researchers to form supportive communities around journals that facilitate their research interests. The alternative may be a withering of the spaces for academic discourse, a stifling of innovation and a further entrenchment of current perceptions of what counts as ‘quality’ research.
N‐Acetylcysteine infusion does not affect glucose disposal during prolonged moderate‐intensity exercise in humans
Authors: Merry Troy L. , Wadley Glenn D. , Stathis Christos G. , Garnham Andrew P. , Rattigan Stephen , Hargreaves Mark , McConell Glenn K.
Published: March 2010

There is evidence that reactive oxygen species (ROS) signalling is required for normal increases in glucose uptake during contraction of isolated mouse skeletal muscle, and that AMP‐activated protein kinase (AMPK) is involved. The aim of this study was to determine whether ROS signalling is involved in the regulation of glucose disposal and AMPK activation during moderate‐intensity exercise in humans. Nine healthy males completed 80 min of cycle ergometry at 62 ± 1% of peak oxygen consumption (. A 6,6‐2H‐glucose tracer was infused at rest and during exercise, and in a double‐blind randomised cross‐over design, N‐acetylcysteine (NAC) or saline (CON) was co‐infused. NAC was infused at 125 mg kg−1 h−1 for 15 min and then at 25 mg kg−1 h−1 for 20 min before and throughout exercise. NAC infusion elevated plasma NAC and cysteine, and muscle NAC and cysteine concentrations during exercise. Although neither NAC infusion nor exercise significantly affected muscle reduced or oxidised glutathione (GSH or GSSG) concentration (P > 0.05), S‐glutathionylation (an indicator of oxidative stress) of a protein band of ∼270 kDa was increased ∼3‐fold with contraction and this increase was prevented by NAC infusion. Despite this, exercised‐induced increases in tracer determined glucose disposal, plasma lactate, plasma non‐esterified fatty acids (NEFAs), and decreases in plasma insulin were not affected by NAC infusion. In addition, skeletal muscle AMPKα and acetyl‐CoA carboxylase‐β (ACCβ) phosphorylation increased during exercise by ∼3‐ and ∼6‐fold (P < 0.05), respectively, and this was not affected by NAC infusion. Unlike findings in mouse muscle ex vivo, NAC does not attenuate skeletal muscle glucose disposal or AMPK activation during moderate‐intensity exercise in humans.
Study of the driving force for the self-assembly of heterojunction quantum dots (zero D molecules) using finite element analysis
Authors: Eyink K. G. , Grazulis L. , Twyman M. , Mahalingam K.
Published: March 2010

The formation and control of quantum dots have been the focus of considerable research. This research is largely motivated by the unique properties zero dimensional structure possess. During heteroepitaxy, quantum dots form through a self-assembly process in order to reduce the strain energy of the heteroepitaxial material while increasing the surface area. Using this procedure, quantum dots composed of many different materials have been formed on various substrates or buffer layers. These structures have been classified into two basic groups (type I and type II) based on how the dot band structure lines up relative to the surrounding barrier band structure. In the case of a type I quantum dot the dot band gap is contained within the energy range of the band gap of the barrier material. This arrangement is typical for InxGa1−xAs on GaAs and InP. The other type of quantum dot, referred to as type II, indicates that the quantum dot band gap straddles the conduction band (or valence band) of the barrier layer, which is the case of GaSb or InP on GaAs. With this alignment, the hole (or electron) states are located in the quantum dot material while the other state is held in barrier region in the vicinity of the quantum dot through electrostatic interactions. Recently, the authors have shown that quantum dots structures can be formed through the self-assembly process that allow the zero-dimensional region to be composed of multiple materials which produce heterojunctions within the quantum dot structure. In these structures, the authors refer to the initial material as a quantum dot and the second material to be a quantum crown. In this article, they discuss various characteristics of these structures which can be utilized in the production of devices. In addition, they study the variation in strain energy for the nucleation and growth of the crown material on an existing quantum dot structure through finite element analysis. They find that even for compositions which have a significant difference in lattice constant from the existing quantum dot materials, an enhancement exists for nucleating the crown material on the existing quantum dot structure. In addition, by carefully selecting the composition (i.e., lattice constant) of the quantum crown material, the optimum location for nucleation can be controlled.
Molecular beam epitaxy growth and characterization of type-II InAs/GaSb strained layer superlattices for long-wave infrared detection
Authors: Plis E. , Khoshakhlagh A. , Myers S. , Kim H. S. , Gautam N. , Sharma Y. D. , Krishna S. , Lee S. J. , Noh S. K.
Published: March 2010

The authors report on investigation of type-II InAs/GaSb and InAs/InxGa1−xSb strained layer superlattices (SLSs) for long-wave infrared detection. Growth conditions were optimized to obtain nearly lattice matched (Δa/a∼0.03%) 13 ML InAs/7 ML GaSb SLS nBn detector structure with cutoff wavelength of ∼8.5 μm (77 K). Dark current density was equal to 3.2×10−4 A/cm2 (Vb=+50 mV, 77 K) for this detector structure. Thin 10 ML InAs/6 ML In0.35Ga0.65Sb SLS was grown with zero lattice mismatch achieved by incorporation of 2.5 ML of GaAs in every SLS period.
Growth of Znx,Cd(1−x′)Se∕ZnxCdyMg(1−x−y)Se–InP quantum cascade structures for emission in the 3–5μm range
Authors: Charles W. O. , Yao Y. , Franz K. J. , Zhang Q. , Shen A. , Gmachl C. , Tamargo M. C.
Published: March 2010

The molecular beam epitaxial growth and electroluminescence (EL) properties of Zn0.48Cd0.52Se∕Zn0.24Cd0.18Mg0.58Se quantum cascade (QC) structures are reported. The samples were composed of 30 repeats of a three-well active region. Cladding layers were inserted to isolate the core of the EL structure from the heavily doped contact region and to obtain optical confinement. Electroluminescence was observed in the 4–5μm range. The observed narrowing of the electroluminescence linewidth was tentatively attributed, in part, to the incorporation of the ZnCdMgSe waveguide layers. A test sample consisting of multiple asymmetric coupled quantum well active regions separated by quaternary barrier layers was also investigated. The Fourier transform infrared (FTIR) absorption spectroscopy measurements suggest that QC structures with EL emission in the 3–4μm range can be achieved with these materials.
Molecular beam epitaxy and characterization of InGaAs∕AlAs∕AlAsSb coupled double quantum wells with extremely thin coupling barriers
Authors: Mozume T. , Gozu S.
Published: March 2010

In Ga As ∕ Al As ∕ Al As Sb coupled double quantum wells (CDQWs) with extremely thin AlAs coupling barriers between InGaAs wells were gown by molecular beam epitaxy. The structural quality was examined by the high-resolution x-ray diffraction and the high-energy transmission electron microscopy. It is confirmed that the CDQWs with the 2 monolayer (ML) AlAs coupling barrier was successfully grown. Clear and sharp peaks corresponding to interband transitions were observed in the photoreflectance spectra of CDQWs with 2 and 3 ML of AlAs coupling barrier. The calculated transition energies correspond well with the measured energies. By reducing the AlAs coupling barrier thickness from 3 to 2 ML, the interband transition energy was redshifted toward the communication wavelength of 1.55μm as expected.
Hole mobility in pseudomorphic InGaSb quantum well modulation doped with carbon
Authors: Liao Chichih , Cheng K. Y.
Published: March 2010

Carbon-tetrabromide (CBr4) is utilized as the p-type doping source in modulation-doped pseudomorphic In0.3Ga0.7Sb/AlxGa1−xSb quantum well structure. Carbon delta-doping is achieved by switching off group III elements while the flow of CBr4 is on during the growth of AlSb barrier layer. The hole mobility of strained In0.3Ga0.7Sb quantum well decreases monotonically from 600 to 400 cm2/V s while the sheet carrier concentration increases from 7.5×1011 to 4.1×1012 cm−2 with increasing carbon delta-doping.
Investigation of Cu–Al surface alloy formation on Cu substrate
Authors: Sartale Shrikrishna Dattatraya , Yoshitake Michiko
Published: March 2010

The authors investigated the Cu–Al surface alloy formation by depositing thin films of Al by radio frequency magnetron sputtering on commercially available pure copper substrates kept at different temperatures. The crystal structure and composition of the alloys were studied by x-ray diffraction and x-ray photoelectron spectroscopy. Despite the polycrystalline nature of the copper substrate, CuAl alloy films are highly oriented along the Cu(111) direction. The deposition of Al onto Cu substrates in the temperature range from 450 to 500 °C leads to a mixture of intermetallic Cu9Al4 and αCu phases. However, 525 °C deposition temperature is enough to get αCu solid solution. These findings can be replicated on Cu single crystals to get a CuAl alloy free from intermetallic phases, which can be used as a substrate to fabricate an electron emitter with a metal-insulator-metal structure.
Degradation of 150 nm mushroom gate InAlAs/InGaAs metamorphic high electron mobility transistors during dc stressing and thermal storage
Authors: Chen K. H. , Chang C. Y. , Leu L. C. , Lo C. F. , Chu B. H. , Pearton S. J. , Ren F.
Published: March 2010

Reliability studies of InAlAs/InGaAs metamorphic high electron mobility transistors (MHEMTs) grown on GaAs substrates for high frequency/power applications are reported. The MHEMTs were stressed at a drain voltage of 3 V for 36 h, as well as undergoing a thermal storage test at 250 °C for 48 h. The drain current density of the MHEMTs at zero gate bias dropped about 12.5% after either the thermal storage experiment or dc stress. The gate current of the MHEMT devices with thermal storage was much higher than that of devices after dc stress. In the latter case, significant gate sinking was observed by transmission electron microscopy. The main degradation mechanism during thermal storage was the reaction of the Ohmic contact with the underlying semiconductor.
Solving the vibroacoustic equations of plates by minimization of error on a sample of observation points
Authors: Collery Olivier , Guyader Jean-Louis
Published: March 2010

In the context of better understanding and predicting sound transmission through heterogeneous fluid-loaded aircraft structures, this paper presents a method of solving the vibroacoustic problem of plates. The present work considers fluid-structure coupling and is applied to simply supported rectangular plates excited mechanically. The proposed method is based on the minimization of the error of verification of the plate vibroacoustic equation of motion on a sample of points. From sampling comes an aliasing effect; this phenomenon is described and solved using a wavelet-based filter. The proposed approach is validated in presenting very accurate results of sound radiation immersed in heavy and light fluids. The fluid-structure interaction appears to be very well described avoiding time-consuming classical calculations of the modal radiation impedances. The focus is also put on different samplings to observe the aliasing effect. As perspectives sound radiation from a non-homogeneous plate is solved and compared with reference results proving all the power of this method.
Do ferrets perceive relative pitch?
Authors: Yin Pingbo , Fritz Jonathan B. , Shamma Shihab A.
Published: March 2010

The existence of relative pitch perception in animals is difficult to demonstrate, since unlike humans, animals often attend to absolute rather than relative properties of sound elements. However, the results of the present study show that ferrets can be trained using relative pitch to discriminate two-tone sequences (rising vs. falling). Three ferrets were trained using a positive-reinforcement paradigm in which sequences of reference (one to five repeats) and target stimuli were presented, and animals were rewarded only when responding correctly to the target. The training procedure consisted of three training phases that successively shaped the ferrets to attend to relative pitch. In Phase-1 training, animals learned the basic task with sequences of invariant tone-pairs and could use absolute pitch information. During Phase-2 training, in order to emphasize relative cues, absolute pitch was varied each trial within a two-octave frequency range. In Phase-3 training, absolute pitch cues were removed, and only relative cue information was available to solve the task. Two ferrets successfully completed training on all three phases and achieved significant discriminative performance over the trained four-octave frequency range. These results suggest that ferrets can be trained to discern the relative pitch relationship of a sequence of tone-pairs independent of frequency.
Using a reflection model for modeling the dynamic feedback path of digital hearing aids
Authors: Ma Guilin , Gran Fredrik , Jacobsen Finn , Agerkvist Finn
Published: March 2010

Feedback whistling is one of the severe problems with hearing aids, especially in dynamic situations when the users hug, pick up a telephone, etc. This paper investigates the properties of the dynamic feedback paths of digital hearing aids and proposes a model based on a reflection assumption. The model is compared with two existing models: a direct model and an initialization model, using the measured dynamic feedback paths. The comparison shows that the proposed approach is able to model the dynamic feedback paths more efficiently and accurately in terms of mean-square error and maximum stable gain. The method is also extended to dual-microphone hearing aids to assess the possibility of relating the two dynamic feedback paths through the reflection model. However, it is found that in a complicated acoustic environment, the relation between the two feedback paths can be very intricate and difficult to exploit to yield better modeling of the dynamic feedback paths.
Binaural masking level differences in actual and simulated bilateral cochlear implant listeners
Authors: Lu Thomas , Litovsky Ruth , Zeng Fan-Gang
Published: March 2010

At present commercially available bilateral cochlear implants (CIs) improve their users’ speech understanding in noise but they employ two independent speech processors that cannot provide accurate and appropriate interaural level and time differences as seen binaurally in normal hearing (NH) listeners. Previous work suggests that binaural cues are accessible to bilateral CI users when presented to single pairs of pitch-matched electrodes, but the scope was limited and the mechanisms remained unclear. In this study, binaural masking level differences (BMLDs) were measured in five bilateral Nucleus-24 CI users over multiple pairs of pitch-matched electrodes. Average BMLD was 4.6±4.9 dB, but large individual variability prevented significance (p=0.09). Considering just the 125 Hz condition, as in previous work, phase (N0S0 vs N0Sπ) and electrode effects were significant. Compared with simulated bilateral CI users, actual bilateral CI users had proportionally higher thresholds for N0Sπ than N0S0. Together the present results suggest that the performance gap in BMLDs between CI and NH listeners is not due to a lack of sufficient acoustic cues in the temporal envelope domain but to a true binaural deficit related to a central mechanism in deprived binaural processing.
Speech localization in a multitalker mixture
Authors: Kopčo Norbert , Best Virginia , Carlile Simon
Published: March 2010

An experiment was performed that measured, for the frontal audio-visual horizon, how accurately listeners could localize a female-voice target amidst four spatially distributed male-voice maskers. To examine whether listeners can make use of a priori knowledge about the configuration of the sources, performance was examined in two conditions: either the masker locations were fixed (in one of five known patterns) or the locations varied from trial to trial. The presence of maskers disrupted speech localization, even after accounting for reduced target detectability. Averaged across all target locations, the rms error in responses decreased by 20% when a priori knowledge about masker locations was available. The effect was even stronger for the target locations that did not coincide with the maskers (error reduction of 36%), while no change in errors was observed for targets coinciding with maskers. The benefits were reduced when the target-to-masker intensity ratio was increased or when the maskers were in a pattern that made it difficult to make use of the a priori information. The results confirm that localization in speech mixtures is modified by the listener’s expectations about the spatial arrangement of the sources.
Observation of energy cascade creating periodic shock waves in a resonator
Authors: Biwa Tetsushi , Yazaki Taichi
Published: March 2010

Nonlinear excitation of periodic shock waves in high-amplitude standing waves was studied from measurements of the acoustic intensity. A gas column of atmospheric air in a cylindrical resonator was driven sinusoidally by an oscillating piston at the fundamental resonance frequency. Acoustic pressure and axial acoustic particle velocity were simultaneously measured and decomposed into the Fourier components, from which the intensity associated with each of the oscillating modes in the resonator was determined. This letter reports the energy cascade from the driven mode to the second harmonic in the periodic shock waves in the resonator.
Detecting blast-induced infrasound in wind noise
Authors: Howard Wheeler B. , Dillion Kevin L. , Shields F. Douglas
Published: March 2010

Current efforts seek to monitor and investigate such naturally occurring events as volcanic eruptions, hurricanes, bolides entering the atmosphere, earthquakes, and tsunamis by the infrasound they generate. Often, detection of the infrasound signal is limited by the masking effect of wind noise. This paper describes the use of a distributed array to detect infrasound signals from four atmospheric detonations at White Sands Missile Range in New Mexico, USA in 2006. Three of the blasts occurred during times of low wind noise and were easily observed with array processing techniques. One blast was obscured by high wind conditions. The results of signal processing are presented that allowed localization of the blast-induced signals in the presence of wind noise in the array response.
High frequency poroelastic waves in hydrogels
Authors: Chiarelli Piero , Lanatà Antonio , Carbone Marina , Domenici Claudio
Published: March 2010

In this work a continuum model for high frequency poroelastic longitudinal waves in hydrogels is presented. A viscoelastic force describing the interaction between the polymer network and the bounded water present in such materials is introduced. The model is tested by means of ultrasound wave speed and attenuation measurements in polyvinylalcohol hydrogel samples. The theory and experiments show that ultrasound attenuation decreases linearly with the increase in the water volume fraction β of the hydrogel. The introduction of the viscoelastic force between the bounded water and the polymer network leads to a bi-phasic theory, showing an ultrasonic fast wave attenuation that can vary as a function of the frequency with a non-integer exponent in agreement with the experimental data in literature. When β tends to 1 (100% of interstitial water) due to the presence of bounded water in the hydrogel, the ultrasound phase velocity acquires higher value than that of pure water. The ultrasound speed gap at β=1 is confirmed by the experimental results, showing that it increases in less cross-linked gel samples which own a higher concentration of bounded water.
The importance of temporal fine structure information in speech at different spectral regions for normal-hearing and hearing-impaired subjects
Authors: Hopkins Kathryn , Moore Brian C. J.
Published: March 2010

Speech reception thresholds (SRTs) were measured for target and competing-speech signals, processed to contain variable amounts of temporal fine structure (TFS) information. Signals were filtered into 30 1-ERBN wide channels (where ERBN refers to the bandwidth of normal auditory filters), which were either tone vocoded, preserving temporal envelope information (extracted using the Hilbert transform), or left unprocessed, containing both TFS and envelope information. Improvements in SRT were compared when TFS was progressively introduced, starting with the high- or low-frequency channels. The results suggest some redundancy in the TFS information across frequency regions. In a second experiment, the signal was divided into five, 6-ERBN-wide spectral regions, four of which were tone vocoded. The remaining region was either absent (creating a spectral notch) or was present and unprocessed. SRTs were measured for normal-hearing and hearing-impaired subjects. Conditions where all channels were vocoded or unprocessed were also included. Normal-hearing subjects benefited similarly when TFS information was added to each region, suggesting that TFS information is important over a wide frequency range. Hearing-impaired subjects benefited less, although the benefit varied across subjects. Benefit from TFS information in speech was correlated with a psychophysical measure of TFS sensitivity obtained at two center frequencies.
Consonant identification in consonant-vowel-consonant syllables in speech-spectrum noise
Authors: Woods David. L. , Yund E. William , Herron Timothy J. , Cruadhlaoich Matthew A. I. Ua
Published: March 2010

Identification functions of 20 initial and 20 final consonants were characterized in 9600 randomly sampled consonant-vowel-consonant (CVC) tokens presented in speech-spectrum noise. Because of differences in the response criteria for different consonants, signal detection measures were used to quantify identifiability. Consonant-specific baseline signal-to-noise ratios (SNRs) were adjusted to produce a d′ of 2.20 for each consonant. Consonant identification was measured at baseline SNRs (B), at B−6, and at B+6 dB. Baseline SNRs varied by more than 40 dB for different consonants. Confusion analysis revealed that single-feature place-of-articulation errors predominated at the highest SNR, while combined-feature errors predominated at the lowest SNR. Most consonants were identified at lower SNRs in initial than final syllable position. Vowel nuclei (/ɑ/, /i/, or /u/) significantly influenced the identifiability of 85% of consonants, with consistent vowel effects seen for consonant classes defined by manner, voicing, and place. Manner and voicing of initial and final consonants were processed independently, but place cues interacted: initial and final consonants differing in place of articulation were identified more accurately than those sharing the same place. Consonant identification in CVCs reveals contextual complexities in consonant processing.