bluuebunny/crossref_metadata_2025 huggingface dataset:
Fully secure ciphertext policy attribute‐based encryption with constant length ciphertext and faster decryption
Authors: Doshi Nishant , Jinwala Devesh C.
Published: November 2013

In PKC 2010, Herranz et al. proposed the first fully threshold ciphertext policy attribute‐based encryption (CP‐ABE) scheme with constant length ciphertext. However, their scheme is selectively secure with respect to the chosen plaintext attack. They have left three open problems for CP‐ABE with constant ciphertext length, that is, Security against the Chosen Ciphertext Attacks, Security Reduction to a better mathematical problem and to make the scheme Fully Secure. Indeed, in ACISP 2012, Ge et al. proposed the solutions to the first two problems but left their proposed scheme selective secure. This makes their scheme weaker because it is secure only for a particular policy. With an aim to propose a fully secure constant ciphertext length CP‐ABE scheme, in this paper, we discuss our attempts at extending the approach of Lewko et al. (in EUROCRYPT 2010). The scheme that we propose here allows any subset of attributes of the secret key as a part of the ciphertext policy. Copyright © 2013 John Wiley & Sons, Ltd.
Gravity duals of $ \mathcal{N} $ = 2 superconformal field theories with no electrostatic description
Authors: Petropoulos P. Marios , Sfetsos Konstadinos , Siampos Konstadinos
Published: November 2013

Abstract

We construct the first eleven-dimensional supergravity solutions, which are regular, have no smearing and possess only SO(2, 4) × SO(3) × U(1)
R
isometry. They are dual to four-dimensional field theories with
$ \mathcal{N} $
= 2 superconformal symmetry. We utilise the Toda frame of self-dual four-dimensional Euclidean metrics with SU(2) rotational symmetry. They are obtained by transforming the Atiyah-Hitchin instanton under SL(2,
$ \mathbb{R} $
) and are expressed in terms of theta functions. The absence of any extra U(1) symmetry, even asymptotically, renders inapplicable the electrostatic description of our solution.
Rare variants in LRRK1 and Parkinson's disease
Authors: Schulte Eva C. , Ellwanger Daniel C. , Dihanich Sybille , Manzoni Claudia , Stangl Katrin , Schormair Barbara , Graf Elisabeth , Eck Sebastian , Mollenhauer Brit , Haubenberger Dietrich , Pirker Walter , Zimprich Alexander , Brücke Thomas , Lichtner Peter , Peters Annette , Gieger Christian , Trenkwalder Claudia , Mewes Hans-Werner , Meitinger Thomas , Lewis Patrick A. , Klünemann Hans H. , Winkelmann Juliane
Published: November 2013

Approximately 20 % of individuals with Parkinson's disease (PD) report a positive family history. Yet, a large portion of causal and disease-modifying variants is still unknown. We used exome sequencing in two affected individuals from a family with late-onset PD to identify 15 potentially causal variants. Segregation analysis and frequency assessment in 862 PD cases and 1,014 ethnically matched controls highlighted variants in EEF1D and LRRK1 as the best candidates. Mutation screening of the coding regions of these genes in 862 cases and 1,014 controls revealed several novel non-synonymous variants in both genes in cases and controls. An in silico multi-model bioinformatics analysis was used to prioritize identified variants in LRRK1 for functional follow-up. However, protein expression, subcellular localization, and cell viability were not affected by the identified variants. Although it has yet to be proven conclusively that variants in LRRK1 are indeed causative of PD, our data strengthen a possible role for LRRK1 in addition to LRRK2 in the genetic underpinnings of PD but, at the same time, highlight the difficulties encountered in the study of rare variants identified by next-generation sequencing in diseases with autosomal dominant or complex patterns of inheritance.
Habitat-specific type I polyketide synthases in soils and street sediments
Authors: Hill Patrick , Piel Jörn , Aris-Brosou Stéphane , Krištůfek Václav , Boddy Christopher N , Dijkhuizen Lubbert
Published: November 2013

Actinomycetes produce many pharmaceutically useful compounds through type I polyketide biosynthetic pathways. Soil has traditionally been an important source for these actinomycete-derived pharmaceuticals. As the rate of antibiotic discovery has decreased and the incidence of antibiotic resistance has increased, researchers have looked for alternatives to soil for bioprospecting. Street sediment, where actinomycetes make up a larger fraction of the bacterial population than in soil, is one such alternative environment. To determine if these differences in actinomycetal community structure are reflected in type I polyketide synthases (PKSI) distribution, environmental DNA from soils and street sediments was characterized by sequencing amplicons of PKSI-specific PCR primers. Amplicons covered two domains: the last 80 amino acids of the ketosynthase (KS) domain and the first 240 amino acids of the acyltransferase (AT) domain. One hundred and ninety clones from ten contrasting soils from six regions and nine street sediments from six cities were sequenced. Twenty-five clones from two earthworm-affected samples were also sequenced. UniFrac lineage-specific analysis identified two clades that clustered with actinomycetal GenBank matches that were street sediment-specific, one similar to the PKSI segment of the mycobactin siderophore involved in mycobacterial virulence. A clade of soil-specific sequences clustered with GenBank matches from the ambruticin and jerangolid pathways of Sorangium cellulosum. All three of these clades were found in sites >700 km apart. Street sediments are enriched in actinomycetal PKSIs. Non-actinomycetal PKSI pathways may be more chemically diverse than actinomycetal PKSIs. Common soil and street sediment PKIs are globally distributed.
Feasibility and validity of ecological momentary assessment in adolescents with high‐functioning autism and Asperger's disorder
Authors: Khor Angela S. , Gray Kylie M. , Reid Sophie C. , Melvin Glenn A.
Published: November 2013

Ecological Momentary Assessment (EMA) may increase accuracy of data compared with retrospective questionnaires by assessing behaviours as they occur, hence decreasing recall biases and increasing ecological validity. This study examined the feasibility and concurrent validity of an EMA tool for adolescents with High‐Functioning Autism Spectrum Disorders (HFASD). Thirty‐one adolescents with HFASD completed a mobile phone EMA application that assessed stressors and coping for two weeks. Parents and adolescents also completed retrospective measures of the adolescent's coping/stressors. Moderate compliance with the EMA tool was achieved and some concurrent validity was established with the retrospective measure of coping. Concordance was found between the types of stressors reported by parents and adolescents but not the quantity. The results suggest adolescents with HFASD are capable of reporting on their stressors and coping via EMA. EMA has the potential to be a valuable research tool in this population.
Weak observability estimates for 1-D wave equations with rough coefficients
Authors: Fanelli Francesco , Zuazua Enrique
Published: November 2013

In this paper we prove observability estimates for 1-dimensional wave equations with non-Lipschitz coefficients. For coefficients in the Zygmund class we prove a “classical” estimate, which extends the well-known observability results in the energy space for
BV
regularity. When the coefficients are instead log-Lipschitz or log-Zygmund, we prove observability estimates “with loss of derivatives”: in order to estimate the total energy of the solutions, we need measurements on some higher order Sobolev norms at the boundary. This last result represents the intermediate step between the Lipschitz (or Zygmund) case, when observability estimates hold in the energy space, and the Hölder one, when they fail at any finite order (as proved in [9]) due to an infinite loss of derivatives. We also establish a sharp relation between the modulus of continuity of the coefficients and the loss of derivatives in the observability estimates. In particular, we will show that under any condition which is weaker than the log-Lipschitz one (not only Hölder, for instance), observability estimates fail in general, while in the intermediate instance between the Lipschitz and the log-Lipschitz ones they can hold only admitting a loss of a finite number of derivatives. This classification has an exact counterpart when considering also the second variation of the coefficients.

Dans cet article on démontre des inégalités d'observabilité pour l'équation des ondes à coefficients non-Lipschitzien en une dimension d'espace. Pour des coefficients qui sont dans la classe de Zygmund, on prouve une estimation « classique », qui étend le résultat bien connu d'observabilité dans l'espace d'énergie pour des coefficients à variation bornée. Au contraire, quand les coefficients sont log-Lipschitz ou log-Zygmund, on prouve des estimations d'observabilité « avec perte de dérivées » : pour contrôler l'énergie totale des solutions, il faut mesurer des normes de Sobolev d'ordre plus élevé au bord de l'intervalle. Ce dernier résultat représente le cas intermédiaire entre le cas des coefficients Lipschitz (ou Zygmund), où les estimations d'observabilité sont satisfaites dans l'espace d'énergie, et celui des coefficients Hölder, où elles échouent à n'importe quel ordre (comme prouvé dans [9]) à cause d'une perte infinie de dérivées. On établit aussi une relation optimale entre le module de continuité des coefficients et la perte de dérivées dans les inégalités d'observabilité. En particulier, on démontre que, quelle que soit l'hypothèse plus faible que celle de log-Lipschitz (pas seulement celle de Hölder, par exemple), les estimations ne sont pas valables en général, tandis que pour toute condition intermédiaire entre celle de Lipschitz et log-Lipschitz on a une inégalité avec une perte d'un nombre fini de dérivées. Cette classification a un équivalent aussi au niveau de la variation seconde des coefficients.
Permeability through a perforated domain for the incompressible 2D Euler equations
Authors: Bonnaillie-Noël V. , Lacave C. , Masmoudi N.
Published: November 2013

We investigate the influence of a perforated domain on the 2D Euler equations. Small inclusions of size
ε
are uniformly distributed on the unit segment or a rectangle, and the fluid fills the exterior. These inclusions are at least separated by a distance

\varepsilon ^{\alpha }

and we prove that for
α
small enough (namely, less than 2 in the case of the segment, and less than 1 in the case of the square), the limit behavior of the ideal fluid does not feel the effect of the perforated domain at leading order when

\varepsilon \rightarrow 0

.
Use of principal component analysis for identification of Rockland and Trego Hot Springs tephras in the Hat Creek Graben, northeastern California, USA
Authors: Pouget Solène , Bursik Marcus , Cortés Joaquín A. , Hayward Chris
Published: November 2013

Discontinuous tephra layers were discovered at Burney Spring Mountain, northern California. Stratigraphic relationships suggest that they are two distinct tephras. Binary plots and standard similarity coefficients of electron probe microanalysis data have been supplemented with principal component analysis to correlate the two tephra layers to known regional tephras. Using principal component analysis, we are furthermore able to bound our uncertainty in the correlation of the two tephra layers. After removal of outliers, within the 95% prediction interval, we can say that one tephra layer is likely the Rockland tephra, aged 565–610 ka, and the second layer is likely from Mt. Mazama, the Trego Hot Springs tephra, aged ~ 29 ka. In the case of the Rockland tephra, the new findings suggest that dispersal to the north was highly restricted. For Trego Hot Springs ash, the new findings extend the distribution to the southwest, with a rapid thinning in that direction. Coupled with considerations of regular tephra dispersal patterns, the results suggest that the primary dispersal direction for both tephras was to the south, and that occurrences in other directions are unlikely or otherwise anomalous.
A Candidate for the Abelian Category of Mixed Elliptic Motives
Authors: Patashnick Owen
Published: November 2013

In this work, we s uggest a defnition for the category of mixed motives generated by the motive h1 (E) for E an elliptic curve without complex multiplication. We then compute the cohomology of this category. Modulo a strengthening of the Beilinson-Soulé conjecture, we show that the cohomology of our category agrees with the expected motivic cohomology groups. Finally for each pure motive (Symnh1 (E)) (–1) we construct families of nontrivial motives whose highest associated weight graded piece is (Symnh1 (E)) (–1).
Equivariant KK-theory for generalised actions and Thom isomorphism in groupoid twisted K-theory
Authors: Moutuou El-Kaïoum M.
Published: November 2013

We develop equivariant KK–theory for locally compact groupoid actions by Morita equivalences on real and complex graded C*-algebras. Functoriality with respect to generalised morphisms and Bott periodicity are discussed. We introduce Stiefel-Whitney classes for real or complex equivariant vector bundles over locally compact groupoids to establish the Thom isomorphism theorem in twisted groupoid K–theory.
Recent advances in animal model experimentation in autism research
Authors: Tania Mousumi , Khan Md. Asaduzzaman , Xia Kun
Published: November 2013

Objective

Autism, a lifelong neuro-developmental disorder is a uniquely human condition. Animal models are not the perfect tools for the full understanding of human development and behavior, but they can be an important place to start. This review focused on the recent updates of animal model research in autism.

Methods

We have reviewed the publications over the last three decades, which are related to animal model study in autism.

Results

Animal models are important because they allow researchers to study the underlying neurobiology in a way that is not possible in humans. Improving the availability of better animal models will help the field to increase the development of medicines that can relieve disabling symptoms. Results from the therapeutic approaches are encouraging remarkably, since some behavioral alterations could be reversed even when treatment was performed on adult mice. Finding an animal model system with similar behavioral tendencies as humans is thus vital for understanding the brain mechanisms, supporting social motivation and attention, and the manner in which these mechanisms break down in autism. The ongoing studies should therefore increase the understanding of the biological alterations associated with autism as well as the development of knowledge-based treatments therapy for those struggling with autism.

Conclusion

In this review, we have presented recent advances in research based on animal models of autism, raising hope for understanding the disease biology for potential therapeutic intervention to improve the quality of life of autism individuals.
PLANT SPECIES MIXTURES FOR FORAGE PRODUCTION FOR RUMINANT FEEDING UNDER MEDITERRANEAN CONDITIONS
Authors: TSIPLAKOU E. , ECONOMOU G. , HADJIGEORGIOU I. , KOMINAKIS A. , ZERVAS G.
Published: November 2013

The establishment of leys for biomass production during the winter months could be an alternative feed resource of low cost for small ruminants in Mediterranean basin. For this purpose, an experiment was carried out with six plant species mixtures (PSM) that were cut up to seven times from seeding. The results showed that all the PSM had their highest growth at the 2nd cut withFestuca arundinacea,Lolium perenne,Dactylis glomerata,Trifolium repens(FLDT) being superior as the dry matter production concerns compared with the PSM that gave seven cuts. The crude protein and the ether extracts contents in all the PSM decreased from the 1st to the last cut, while that of NDF and ADF increased. The concentrations of myristic, palmitic, stearic, oleic and linoleic acid increased in all the PSMs from the 2nd to the 5th cut, while the opposite was observed for the α-linolenic acid content. The concentration of α-linolenic acid was higher in the FLDT PSM when compared to others during all cuts. Taking into account all the examined parameters together, the FLDT seems to be superior to the other PSMs as animal feed for small ruminants, particularly during the period where there is no available grass from natural grasslands.
Property Rights Under Administrator-Dictators: The Rise and Fall of America's First Bank
Authors: Goldberg Dror , Milchtaich Igal
Published: November 2013

The dictatorial Dominion of New England (1686–1689) saw the rise and fall of the first operational bank scheme in America. Both events resulted from the appointed rulers' attempts to personally profit from real estate, subject to an absolutist constitution imposed by England. The first,localruler led a nominally private land bank. The subsequent,foreignruler invalidated all land titles and thus killed the bank. This unusual case study exemplifies an extension of Mancur Olson's model of stationary and roving bandits, and demonstrates how economic development can be affected in different ways by different types of dictators.
Spatial segregation and similar trophic-level diet among eastern Canadian Arctic/north-west Atlantic killer whales inferred from bulk and compound specific isotopic analysis
Authors: Matthews Cory J.D. , Ferguson Steven H.
Published: November 2013

Killer whales in the Eastern Canadian Arctic (ECA) prey on narwhal, beluga, bowhead whales and seals, while further south in the north-west Atlantic (NWA), killer whales off the coast of Newfoundland and Labrador prey on both marine mammals and fish. Bulk and amino acid (AA) specific isotopic composition of dentinal collagen in teeth of 13 ECA/NWA killer whales were analysed to assess the degree, if any, of dietary specialization of killer whales across the region. Dentine was sampled from within annual growth layer groups (GLGs) to construct chronological profiles of stable nitrogen (δ15N) and carbon (δ13C) isotopic compositions for individual whales spanning 3–25 years. Interannual isotopic variation across GLGs was less than that among individuals, and median bulk δ15N values differed by up to 5‰ among individuals. Significant correlation between bulk δ15N values and baseline (source AA) δ15N values indicates much of the observed isotopic variation among individuals reflects foraging within isotopically distinct food webs, rather than diet differences. This interpretation is supported by consistent differences in bulk δ13C values between the two individuals with lowest source AA δ15N values and the remaining whales. After accounting for baseline isotopic variation, comparable δ15N values among individuals indicates similar trophic-level diet, although uncertainties in relative trophic15N enrichment of individual AAs currently limits trophic position estimates for top consumers. Further research is required to clarify seasonal movement patterns and possible diet shifts of ECA/NWA killer whales to better define their role in marine ecosystems across the region.
Group therapy for people with bulimia nervosa: systematic review and meta-analysis
Authors: Polnay A. , James V. A. W. , Hodges L. , Murray G. D. , Munro C. , Lawrie S. M.
Published: November 2013

Background

Approximately 25% of people with bulimia nervosa (BN) who undertake therapy are treated in groups. National guidelines do not discriminate between group and individual therapy, yet each has potential advantages and disadvantages and it is unclear how their effects compare. We therefore evaluated how group therapy for BN compares with individual therapy, no treatment, or other therapies, in terms of remission from binges and binge frequency.

Method

We performed a systematic review and meta-analysis of randomized controlled trials of group therapies for BN, following standard guidelines.

Results

A total of 10 studies were included. Studies were generally small with unclear risk of bias. There was low-quality evidence of a clinically relevant advantage for group cognitive behavioural therapy (CBT) over no treatment at therapy end. Remission was more likely with group CBT versus no treatment [relative risk (RR) 0.77, 95% confidence interval (CI) 0.62–0.96]. Mean weekly binges were lower with group CBT versus no treatment (2.9 v. 6.9, standardized mean difference = −0.56, 95% CI −0.96 to −0.15). One study provided low-quality evidence that group CBT was inferior compared with individual CBT to a clinically relevant degree for remission at therapy end (RR 1.24, 95% CI 1.03–1.50); there was insufficient evidence regarding frequency of binges.

Conclusions

Conclusions could only be reached for CBT. Low-quality evidence suggests that group CBT is effective compared with no treatment, but there was insufficient or very limited evidence about how group and individual CBT compared. The risk of bias and imprecise estimates of effect invite further research to refine and increase confidence in these findings.
Bacterial lipodipeptide, Lipid 654, is a microbiome‐associated biomarker for multiple sclerosis
Authors: Farrokhi Vahid , Nemati Reza , Nichols Frank C , Yao Xudong , Anstadt Emily , Fujiwara Mai , Grady James , Wakefield Daniel , Castro Wanda , Donaldson James , Clark Robert B
Published: November 2013

Multiple sclerosis (MS) is an autoimmune disease of unknown etiology. Infectious agents have been suggested to have a role as environmental factors in MS, but this concept remains controversial. Recently, gastrointestinal commensal bacteria have been implicated in the pathogenesis of autoimmune diseases, but mechanisms underlying the relationship of human systemic autoimmunity with the commensal microbiome have yet to be identified. Consistent with the lack of understanding of pathogenic mechanisms and relevant environmental factors in MS, no blood biomarkers have been identified that distinguish MS patients from healthy individuals. We recently identified a unique gastrointestinal and oral bacteria‐derived lipodipeptide, Lipid 654, which is produced by commensal bacteria and functions as a human and mouse Toll‐like receptor 2 ligand. Using multiple‐reaction‐monitoring mass spectrometry, a critical approach in targeted lipidomics, we now report that Lipid 654 can be recovered in the serum of healthy individuals. Most interestingly, we find that Lipid 654 is expressed at significantly lower levels in the serum of patients with MS compared with both healthy individuals and patients with Alzheimer's disease. These results thus identify for the first time a potential mechanism relating the gastrointestinal and oral commensal microbiome to a human systemic autoimmune disease. In addition, these results also identify a potential etiologic environmental factor and novel clinically relevant serum biomarker for MS.
Building and remodelling Cullin–RING E3 ubiquitin ligases
Authors: Lydeard John R , Schulman Brenda A , Harper J Wade
Published: November 2013

Cullin–RING E3 ubiquitin ligases (CRLs) control a plethora of biological pathways through targeted ubiquitylation of signalling proteins. These modular assemblies use substrate receptor modules to recruit specific targets. Recent efforts have focused on understanding the mechanisms that control the activity state of CRLs through dynamic alterations in CRL architecture. Central to these processes are cycles of cullin neddylation and deneddylation, as well as exchange of substrate receptor modules to re‐sculpt the CRL landscape, thereby responding to the cellular requirements to turn over distinct proteins in different contexts. This review is focused on how CRLs are dynamically controlled with an emphasis on how cullin neddylation cycles are integrated with receptor exchange.
mTOR plays critical roles in pancreatic cancer stem cells through specific and stemness-related functions
Authors: Matsubara Shyuichiro , Ding Qiang , Miyazaki Yumi , Kuwahata Taisaku , Tsukasa Koichiro , Takao Sonshin
Published: November 2013

Pancreatic cancer is characterized by near-universal mutations in KRAS. The mammalian target of rapamycin (mTOR), which functions downstream of RAS, has divergent effects on stem cells. In the present study, we investigated the significance of the mTOR pathway in maintaining the properties of pancreatic cancer stem cells. The mTOR inhibitor, rapamycin, reduced the viability of CD133+ pancreatic cancer cells and sphere formation which is an index of self-renewal of stem-like cells, indicating that the mTOR pathway functions to maintain cancer stem-like cells. Further, rapamycin had different effects on CD133+ cells compared to cyclopamine which is an inhibitor of the Hedgehog pathway. Thus, the mTOR pathway has a distinct role although both pathways maintain pancreatic cancer stem cells. Therefore, mTOR might be a promising target to eliminate pancreatic cancer stem cells.
A DFT study of oxygen dissociation on platinum based nanoparticles
Authors: Jennings Paul C. , Aleksandrov Hristiyan A. , Neyman Konstantin M. , Johnston Roy L.
Published: November 2013

A DFT investigation of O2 activation on pure Pt and Ti@Pt core–shell nanoparticles and the importance of shell flexibility for fast reaction kinetics.
Spatiotemporal effects of a bioautocatalytic chemical wave revealed by time-resolved mass spectrometry
Authors: Ting Hsu , Urban Pawel L.
Published: November 2013

Mass spectrometry has been implemented as an on-line detection tool to monitor transmission of chemical signals due to natural processes such as diffusion and convection as well as a bienzymatic autocatalytic process.
SIM-dependent enhancement of substrate-specific SUMOylation by a ubiquitin ligase in vitro
Authors: Parker Joanne L. , Ulrich Helle D.
Published: November 2013

SIMs (SUMO-interaction motifs), which mediate the non-covalent binding of SUMO (small ubiquitin-related modifier) to other proteins, are usually involved in the recognition of SUMOylated substrates by downstream effectors that transmit the biological signal of the modification. In ubiquitin ligase Rad18 (radiation-sensitive 18) from Saccharomyces cerevisiae, a SIM, contributes to the recognition of SUMOylated PCNA (proliferating-cell nuclear antigen) as its physiological ubiquitylation target. In the present study we show that Rad18 is also capable of enhancing PCNA SUMOylation in a SIM-dependent manner in vitro, most probably by means of directing SUMO-loaded Ubc9 (ubiquitin-conjugating enzyme 9) towards the substrate. The process shares important features with Rad18-dependent ubiquitylation, such as an exquisite specificity for the modification site on PCNA and the requirement of DNA, and the reaction proceeds under conditions that are widely used in other in vitro assays for SUMO ligase activity. However, there is no evidence that Rad18 contributes to PCNA SUMOylation in vivo. The findings of the present study therefore illustrate the problematic nature of in vitro SUMOylation assays and highlight the danger of extrapolating from this type of experiment to the biological function of a SUMO-interacting protein.
Molecular basis of cancer-therapy-induced cardiotoxicity: introducing microRNA biomarkers for early assessment of subclinical myocardial injury
Authors: Sandhu Hardip , Maddock Helen
Published: November 2013

Development of reliable biomarkers for early clinical assessment of drug-induced cardiotoxicity could allow the detection of subclinical cardiac injury risk in vulnerable patients before irreversible damage occurs. Currently, it is difficult to predict who will develop drug-induced cardiotoxicity owing to lack of sensitivity and/or specificity of currently used diagnostics. miRNAs are mRNA regulators and they are currently being extensively profiled for use as biomarkers due to their specific tissue and disease expression signature profiles. Identification of cardiotoxicity-specific miRNA biomarkers could provide clinicians with a valuable tool to allow prognosis of patients at risk of cardiovascular injury, alteration of a treatment regime or the introduction of an adjunct therapy in order to increase the long-term survival rate of patients treated with cardiotoxic drugs.
In vivoevidence of an age-related increase in ATP cost of contraction in the plantar flexor muscles
Authors: Layec Gwenael , Trinity Joel D. , Hart Corey R. , Kim Seong-Eun , Groot Henderik Jonathan , Le Fur Yann , Sorensen Jacob R. , Jeong Eun-Kee , Richardson Russell S.
Published: November 2013

Impaired skeletal muscle efficiency potentially contributes to the age-related decline in exercise capacity and may explain the altered haemodynamic response to exercise in the elderly. Thus we examined whether (i) the ATP cost of contraction increases with age, and (ii) this results in altered convective O2 delivery to maintain microvascular oxygenation in the calf muscle. To this aim, we used an integrative experimental approach combining 31P-MRS (magnetic resonance spectroscopy), Doppler ultrasound imaging and NIRS (near-IR spectroscopy) during dynamic plantar flexion exercise at 40% of WRmax (maximal power output) in 20 healthy young and 20 older subjects matched for physical activity. The ATP cost of contraction was significantly higher in the old (7.2±4.1 mM/min per W) compared with the young (2.4±1.9 mM/min per W; P<0.05) and this was only significantly correlated with the plantar flexion WRmax value in the old subjects (r=−0.52; P<0.05). Even when differences in power output were taken into account, end-exercise blood flow (old, 259±168 ml/min per W and young, 134±40 ml/min per W; P<0.05) and convective O2 delivery (old, 0.048±0.031 l/min per W and young, 0.026±0.008 l/min per W; P<0.05) were greater in the old in comparison with the young subjects. In contrast, the NIRS oxyhaemoglobin, deoxyhaemoglobin and microvascular oxygenation indices were not significantly different between the groups (P>0.05). Therefore the present study reveals that, although the peripheral haemodynamic responses to plantar flexion exercise appear to be appropriate, the elevated energy cost of contraction and associated reduction in the WRmax value in this muscle group may play a role in limiting exercise capacity with age.
A model for low temperature interface passivation between amorphous and crystalline silicon
Authors: Mitchell J.
Published: November 2013

Excellent passivation of the crystalline surface is known to occur following post-deposition thermal annealing of intrinsic hydrogenated amorphous silicon thin-film layers deposited by plasma-enhanced chemical vapour deposition. The hydrogen primarily responsible for passivating dangling bonds at the crystalline silicon surface has often been singularly linked to a bulk diffusion mechanism within the thin-film layer. In this work, the origins and the mechanism by which hydrogen passivation occurs are more accurately identified by way of an interface-diffusion model, which operates independent of the a-Si:H bulk. This first-principles approach achieved good agreement with experimental results, describing a linear relationship between the average diffusion lengths and anneals temperature. Similarly, the time hydrogen spends between shallow-trap states is shown to decrease rapidly with increases in temperature circuitously related to probabilistic displacement distances. The interface reconfiguration model proposed in this work demonstrates the importance of interface states and identifies the misconception surrounding hydrogen passivation of the c-Si surface.
Measuring non-condensable gases in steam
Authors: van Doornmalen J. P. C. M. , Kopinga K.
Published: November 2013

In surgery, medical devices that are used should be sterilized. To obtain surface steam sterilization conditions, not only in the sterilizer chamber itself but also in the loads to be sterilized, the amount of non-condensable gases (NCGs), for instance air, should be very low. Even rather small fractions of NCGs (below 1 %) seriously hamper steam penetration in porous materials or devices with hollow channels (e.g., endoscopes). A recently developed instrument which might detect the presence of residual NCGs in a reliable and reproducible way is the 3MTM Electronic Test System (ETS). In this paper, a physical model is presented that describes the behavior of this instrument. This model has been validated by experiments in which known fractions of NCGs were introduced in a sterilizer chamber in which an ETS was placed. Despite several approximations made in the model, a good agreement is found between the model predictions and the experimental results. The basic principle of the ETS, measuring the heat transfer by condensation on a cooled surface, permits a very sensitive detection of NCGs in harsh environments like water vapor at high temperatures and pressures. Our model may serve to develop adapted and optimized versions of this instrument for use outside the field of sterilization, e.g., in heat exchangers based on steam condensation.
Phase separation of mixed polymer brushes on surfaces with nonuniform curvature
Authors: Tung Clarion , Cacciuto A.
Published: November 2013

Using numerical simulations and a simple scaling theory, we study the microphase separation of a mixture of polymer brushes with different chain lengths tethered to surfaces with nonuniform curvature. We measure the free energy difference of the phase separated configurations as a function of spheroid eccentricity and ordering of the microdomains formed on them. We find that there is a preference for the longer chains to locate in high curvature regions, and identify and quantify the driving forces associated with this phenomenon. We also find that nonuniform curvature typically limits the number of striped domains that would normally form on a spherical surface under identical physical conditions. Finally, we generalize the scaling theory developed for brushes on spherical surfaces to include prolate and oblate spheroids, and show explicitly that while immiscibility between the chains is required for phase separation to occur on spheroids, it is unnecessary for certain surfaces with regions of positive and negative curvature. We present a phase diagram showing the conditions under which curvature-driven phase separation of miscible, but lengthwise asymmetric chains is expected to occur.
Iron (III)/multiacrylate-based holographic mixtures
Authors: Lucchetta D. E. , Nucara L. , Criante L. , Simoni F. , Boni A. , Xu Ji-Hua , Bizzarri R. , Castagna R.
Published: November 2013

We propose an holographic mixture, based on a nonconventional photoinitiator mixed with an acrylate monomer, in which high resolution thick holographic gratings are written. The used mixture that preferably works at UV and Blue-visible wavelengths shows many interesting features, such as high post-polymerization transparency, high writing resolution, and high angular selectivity. The information is permanently storable. Standard experimental techniques have been used to characterize the physical properties of the written gratings.
Electrochemical control of creep in nanoporous gold
Authors: Ye Xing-Long , Jin Hai-Jun
Published: November 2013

We have investigated the mechanical stability of nanoporous gold (npg) in an electrochemical environment, using in situ dilatometry and compression experiments. It is demonstrated that the gold nano-ligaments creep under the action of surface stress which leads to spontaneous volume contractions in macroscopic npg samples. The creep of npg, under or without external forces, can be controlled electrochemically. The creep rate increases with increasing potential in double-layer potential region, and deceases to almost zero when the gold surface is adsorbed with oxygen. Surprisingly, we also noticed a correlation between creep and surface diffusivity, which links the deformation of nanocrystals to mobility of surface atoms.
Structure of multilayered Cr(Al)N/SiOx nanocomposite coatings fabricated by differential pumping co-sputtering
Authors: Kawasaki Masahiro , Nose Masateru , Onishi Ichiro , Shiojiri Makoto
Published: November 2013

A Cr(Al)N/38 vol. % SiOx hard coating was prepared on a (001) Si substrate at 250 °C in a differential pumping co-sputtering system, which has two chambers for radio frequency (RF) sputtering and a substrate holder rotating on the chambers. The composite coating was grown by alternate sputter-depositions from CrAl and SiO2 targets with flows of N2+Ar and Ar at RF powers of 200 and 75 W, respectively, on transition layers grown on the substrate. Analytical electron microscopy reveled that the Cr(Al)N/SiOx coating had a multilayered structure of Cr(Al)N crystal layers ∼1.6 nm thick and two-dimensionally dispersed amorphous silicon oxide (a-SiOx) particles with sizes of ∼1 nm or less. The a-SiOx particles were enclosed with the Cr(Al)N layers. The coating had a low indentation hardness of ∼25 GPa at room temperature, due to a high oxide fraction of 38 vol. % and a low substrate rotational speed of 1 rpm. Faster rotation and lower oxide fraction would make a-SiOx particles smaller, resulting in the formation of Cr(Al)N crystal including the very fine a-SiOx particles with small number density. They would work as obstacles for the lattice deformation of the Cr(Al)N crystals. We have fabricated a superhard coating of Cr(Al)N/17 vol. % SiOx with a hardness of 46 GPa prepared at 12 rpm.
Very large dielectric response from ferroelectric nanocapacitor films due to collective surface and strain relaxation effects
Authors: Misirlioglu I. B. , Yildiz M.
Published: November 2013

Dependence of the dielectric response of ferroelectrics on defect types, particularly those with long range strain fields in confined geometries have been often mentioned, especially in interpreting experimental results in films. However, detailed discussions on the mechanisms with which defects alter properties, particularly in the presence of interfaces imposing certain boundary conditions, are seldom made. Here, we studied the thickness dependence of transition temperatures and dielectric response of Metal/BaTiO3/Metal ferroelectric nanocapacitor structures grown on SrTiO3 using a phenomenological approach accounting for the equations of electrostatics and semiconductors. Relaxation of the misfit strain via misfit dislocations amplify the surface effects in films below a critical thickness and favor electrical domains leading to very large dielectric responses in this regime. Thin film structures with relaxed misfit strain in this work are fully depleted in the presence of moderate densities of impurities ( ∼ 1025 m −3). This is due to the reduction of polarization amplitude parallel to the film normal and its mplications for near-micron thick films are discussed. Consequently, the misfit dislocation sites have nearly no free carrier localization, making the role of these sites on leakage currents highly questionable. Dielectric response of intrinsic thicker films ( > 40 nm) is mostly under the influence of strain relaxation only with minimal interface impact in the limit of ideal electrodes. Our results point out that control of the dislocation density can lead to non-conventional functionalities in ferroelectric thin film capacitors via electromechanical coupling of properties to structure and domain stabilization.
Effect of defect clusters on carrier recombination in high-resistivity CdZnTe
Authors: Kamieniecki Emil
Published: November 2013

Carrier recombination in high-resistivity CdZnTe is investigated using the non-contact Defect Specific Photoconductance (DSPC) method that allows for the separation of the photoconductance components associated with recombination at point defects and defect clusters. Unlike photoconductance component controlled by the recombination at point defects that decays exponentially upon cessation of illumination, the component associated with carrier recombination at defect clusters decays logarithmically with time. It is shown that this decay is associated with formation of a Schottky-type depletion space-charge region around the cluster. In high-resistivity CdZnTe the time constant of the logarithmic decay exceeds 1 ms. Reduction of the height of cluster potential barrier with increasing photo-excited excess carrier density increases carrier recombination through the cluster states and leads to its dominance over the recombination through the point defects. At higher carrier injection densities the contribution of the carrier recombination through the clusters exceeds 80% of the total recombination rate.
Fabrication and optical properties of non-polar III-nitride air-gap distributed Bragg reflector microcavities
Authors: Tao Renchun , Arita Munetaka , Kako Satoshi , Arakawa Yasuhiko
Published: November 2013

Using the thermal decomposition technique, non-polar III-nitride air-gap distributed Bragg reflector (DBR) microcavities (MCs) with a single quantum well have been fabricated. Atomic force microscopy reveals a locally smooth DBR surface, and room-temperature micro-photoluminescence measurements show cavity modes. There are two modes per cavity due to optical birefringence in the non-polar MCs, and a systematic cavity mode shift with cavity thickness was also observed. Although the structures consist of only 3 periods (top) and 4 periods (bottom), a quality factor of 1600 (very close to the theoretical value of 2100) reveals the high quality of the air-gap DBR MCs.
Hydrogen passivation of electron trap in amorphous In-Ga-Zn-O thin-film transistors
Authors: Hanyu Yuichiro , Domen Kay , Nomura Kenji , Hiramatsu Hidenori , Kumomi Hideya , Hosono Hideo , Kamiya Toshio
Published: November 2013

We report an experimental evidence that some hydrogens passivate electron traps in an amorphous oxide semiconductor, a-In-Ga-Zn-O (a-IGZO). The a-IGZO thin-film transistors (TFTs) annealed at 300 °C exhibit good operation characteristics; while those annealed at ≥400 °C show deteriorated ones. Thermal desorption spectra (TDS) of H2O indicate that this threshold annealing temperature corresponds to depletion of H2O desorption from the a-IGZO layer. Hydrogen re-doping by wet oxygen annealing recovers the good TFT characteristic. The hydrogens responsible for this passivation have specific binding energies corresponding to the desorption temperatures of 300–430 °C. A plausible structural model is suggested.
Longevity in maternal transmission of isotopic marks in a tropical freshwater rainbowfish and the implications for offspring morphology
Authors: Starrs D. , Ebner B. C. , Eggins S. M. , Fulton C. J.
Published: November 2013

Transgenerational marking is increasingly being used to study the early life history, biology and ecology of fishes. However, the timeframe over which the injected enriched stable isotopes remain in the mother and are passed onto her offspring is largely unknown. Similarly, we have relatively little knowledge of the effects of isotope labelling on the morphology of offspring. In this study, we injected adult female eastern rainbowfish (Melanotaenia splendida) with two doses (20 µg g–1 and 40 µg g–1) of enriched 137Ba or 87Sr stable isotopes to mark the otoliths of their larvae and examine the effects of isotope labelling on larvae morphology. Isotope ratios in larval otoliths were significantly different from controls in larvae hatched up to 174 days post-injection, indicating that enriched isotopes can mark the larvae of this daily spawning species up to 6 months after a single injection. Isotope-marked larvae displayed variable, but generally increased physical size, indicating that enriched stable isotope labelling may have some unintended effects on larvae morphology. Consequently, transgenerational marking provides a long-term tool for marking the offspring of M. splendida to disentangle their patterns of survivorship and dispersal, with the caveat that such studies should be interpreted in light of potential isotope-related changes in offspring morphology.
Green manures and plant disease management.
Authors: Larkin R. P.
Published: November 2013

The use of green manures, which involves the incorporation of fresh plant material, has traditionally been primarily for the purpose of soil enrichment through the addition of plant organic matter and nutrients. However, green manures produce many changes in soil physical, chemical and biological properties, and may also result in suppression of specific plant pathogens and diseases. Green manures increase soil microbial biomass and activity, and cause distinct changes in soil microbial populations that may be partially responsible for suppression of diseases. However, green manures of different crops and cultivars may vary considerably in their activity or efficacy against different pathogens and diseases. In particular, green manures of Brassica and related crops have emerged as most effective for management of multiple plant diseases due to their biofumigation potential, which refers to the suppression of pathogens and disease through the release of volatile toxic breakdown products, as well as other unique effects on soil microbial ecology. Brassica crops and other green manures have been used to control a variety of plant pathogens, including species of
Rhizoctonia
,
Verticillium
,
Sderotinia
,
Phythophthora
,
Pythium
,
Aphanomyces
and
Macrophomina
, in various crop production systems, such as for the management of multiple soilborne diseases of potato, including black scurf, common scab and Verticillium wilt. Although disease reduction with green manures can be variable and provides only partial control, it is a versatile and readily-implementable additional management strategy that should be used as an important component within a larger integrated disease management program to provide improved sustainable production systems.
Polyunsaturated fatty acids and fertility in female mammals: an update.
Authors: Wathes D. C. , Cheng ZhangRui Cheng ZhangRui , Marei W. , Fouladi-Nashta A.
Published: November 2013

Both
n
-3 and
n
-6 polyunsaturated fatty acids (PUFAs) are derived from the diet, with concentrations in the reproductive tract reflecting dietary intake. PUFAs have multiple functions: as precursors to eicosanoids, regulators of steroid biosynthesis, inflammatory mediators and supplying energy (particularly in oocytes). The PUFA composition of cell membranes affects signalling pathways and susceptibility to oxidative damage. All of these roles may influence reproduction although results are often inconsistent between studies. Supplementation of cows with various PUFAs can increase the numbers of antral follicles although work on polyovular species (pigs, rodents) has usually failed to detect a change in ovulation rate. The anti-inflammatory actions of
n
-3 PUFAs may reduce follicular PGE production, delaying ovulation and allowing ovulatory follicles to grow larger and produce more steroid. Various PUFA supplements can reduce the interval from calving until first ovulation in cattle although the mechanism is uncertain. Both
n
-3 and
n
-6 PUFA supplements have been fed to various species before collecting oocytes for
in vitro
fertilization. Positive, negative and no effects on subsequent embryo development have all been reported. When PUFAs are added directly to oocyte maturation medium, high doses of linoleic acid (18:2
n
-6) are consistently deleterious, while α-linolenic acid (18:3
n
-3) has been associated with positive outcomes. Uterine prostaglandin production regulates luteal regression and pregnancy recognition. Supplementary
n
-3 PUFAs have either increased or decreased PGF
2α
production in different studies. There is some evidence that cattle and pigs fed a PUFA supplement post insemination may have an increased pregnancy rate.