bluuebunny/crossref_metadata_2025 huggingface dataset:
The lanthanide contraction within the sparkle model
Authors: Freire Ricardo O. , Simas Alfredo M.
Published: August 2010

The sparkle model has been introduced to allow the a priori quantum chemical calculation of properties, mainly geometries, of lanthanide complexes. In this work, we compute Sparkle/PM3 optimized geometries for the isostructural series of complexes Ln[TREN‐1,2‐HOIQO(H2O)2] and Ln[(H2O)9]3+, with Ln = La‐Lu (except Pm). The results reveal the expected contraction for each series of complexes. We conclude that the lanthanide contraction phenomenon is indeed present within Sparkle/PM3, a fact which can only reinforce the sparkle model as a powerful tool for the prediction and rationalization of the geometric features of lanthanide complexes and for their a priori design. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Active access control (AAC) with fine‐granularity and scalability
Authors: Park Joon S. , An Gaeil , Liu Ivy Y.
Published: August 2010

Strong access control mechanisms become most critical when we need security services in large‐scale computing environments of sensitive organizations. Furthermore, if users join or leave such computing environment frequently, requiring different access control decisions based on their current job responsibilities and contexts, the need for advanced access control is pressing. Although the currently available access control approaches have a great potential for providing reliable service, there are still critical obstacles to be solved, especially in large‐scale, dynamic computing environments. In this paper we introduce an advanced access control mechanism, Active Access Control (AAC), which accounts for the ability to make dynamic access control decisions based not only on pre‐defined privileges, but also on the current situation of the user. The framework of the proposed AAC approach provides fine‐grained access control, by considering a variety of attributes about the user and the current computing environment, especially, when the users contexts are frequently changed. Although the outputs of the AAC approach can be integrated with any other existing access control mechanisms and improve the overall fine‐granularity, as a full demonstration of our approach for fine‐granularity as well as scalability, in this particular paper we focus on large‐scale computing environments and integrate the AAC results with the role‐based approach. Finally, in order to prove the feasibility of our proposed idea we implement the AAC approach with roles and discuss the evaluation results with existing approaches. Copyright © 2010 John Wiley & Sons, Ltd.
Random‐effects meta‐regression models for studying nonlinear dose–response relationship, with an application to alcohol and esophageal squamous cell carcinoma
Authors: Rota Matteo , Bellocco Rino , Scotti Lorenza , Tramacere Irene , Jenab Mazda , Corrao Giovanni , La Vecchia Carlo , Boffetta Paolo , Bagnardi Vincenzo
Published: August 2010

A fundamental challenge in meta‐analyses of published epidemiological dose–response data is the estimate of the function describing how the risk of disease varies across different levels of a given exposure. Issues in trend estimate include within studies variability, between studies heterogeneity, and nonlinear trend components. We present a method, based on a two‐step process, that addresses simultaneously these issues. First, two‐term fractional polynomial models are fitted within each study included in the meta‐analysis, taking into account the correlation between the reported estimates for different exposure levels. Second, the pooled dose–response relationship is estimated considering the between studies heterogeneity, using a bivariate random‐effects model. This method is illustrated by a meta‐analysis aimed to estimate the shape of the dose–response curve between alcohol consumption and esophageal squamous cell carcinoma (SCC). Overall, 14 case–control studies and one cohort study, including 3000 cases of esophageal SCC, were included. The meta‐analysis provided evidence that ethanol intake was related to esophageal SCC risk in a nonlinear fashion. High levels of alcohol consumption resulted in a substantial risk of esophageal SCC as compared to nondrinkers. However, a statistically significant excess risk for moderate and intermediate doses of alcohol was also observed, with no evidence of a threshold effect. Copyright © 2010 John Wiley & Sons, Ltd.
Sleep after stress induction: the role of stressful memory reactivation
Authors: Bader Klaus , Bauer Catherine , Christen Regula , Schäfer Valérie
Published: August 2010

Exposure to extreme stress is known to have immediate as well as long‐term effects on sleep. There is some evidence that adverse childhood experiences as well can increase the vulnerability of sleep to stress in the long term. In order to validate these assumptions, 39 healthy female undergraduate students were exposed to a video stress induction procedure before bedtime. Self‐reports and actigraphic measures were collected through a period of three baseline nights and the test night. Participants' self‐reports of the subsequent night's sleep were significantly associated with the degree to which they reported that the stress inducing film had triggered own stressful memories of their past. This finding supports the assumption that early stress history can increase an individual's vulnerability of sleep to stress, in particularly when actual stressors lead to the reactivation of stressful memories. Yet, actigraphic measures did not corroborate this subjective impression of sleep impairment. Copyright © 2010 John Wiley & Sons, Ltd.
Portability in MAC protocol and transceiver software implementations for LR‐WPAN platforms
Authors: Schoofs Anthony , Stanley‐Marbell Phillip
Published: August 2010

In a variety of emerging networked computing system domains over the years, there have been bursts of activity on new medium access control (MAC) protocols, as new communication transceiver technologies with greater data‐movement performance or lower power dissipation have been introduced. To enable implementations flexible to evolving standards and improving application‐domain insight, such MAC protocols are typically initially implemented in software, and interface between applications or system software, typically executing on an embedded processor or microcontroller, and the evolving radio transceiver hardware. Many challenges exist in implementing MAC protocols across evolving or competing transceiver hardware implementations and processor architectures. Some of these challenges are peculiar to the requirements of MAC protocols, and others are a result of the plethora of system and processor architectures in the embedded systems domain. This article studies the challenges facing software implementations of MAC protocols running on embedded microcontrollers, and interfacing with radio transceiver hardware. Experience with an implementation of the IEEE 802.15.4 MAC across three hardware platforms with different processor, system, and systems software architectures is presented, focusing on implementation approach and interfaces. Pitfalls are pointed out, and guidelines are provided for ensuring that new MAC implementations are easily portable across processor architectures and transceiver hardware. Copyright © 2010 John Wiley & Sons, Ltd.
Allogeneic Periodontal Ligament Stem Cell Therapy for Periodontitis in Swine
Authors: Ding Gang , Liu Yi , Wang Wei , Wei Fulan , Liu Dayong , Fan Zhipeng , An Yunqing , Zhang Chunmei , Wang Songlin
Published: August 2010

Periodontitis is one of the most widespread infectious diseases in humans. It is the main cause of tooth loss and associated with a number of systemic diseases. Until now, there is no appropriate method for functional periodontal tissue regeneration. Here, we establish a novel approach of using allogeneic periodontal ligament stem cells (PDLSCs) sheet to curing periodontitis in a miniature pig periodontitis model. Significant periodontal tissue regeneration was achieved in both the autologous and the allogeneic PDLSCs transplantation group at 12 weeks post-PDLSCs transplantation. Based on clinical assessments, computed tomography (CT) scanning, and histological examination, there was no marked difference between the autologous and allogeneic PDLSCs transplantation groups. In addition, lack of immunological rejections in the animals that received the allogeneic PDLSCs transplantation was observed. Interestingly, we found that human PDLSCs fail to express human leukocyte antigen (HLA)-II DR and costimulatory molecules. PDLSCs were not able to elicit T-cell proliferation and inhibit T-cell proliferation when stimulated with mismatched major histocompatibility complex molecules. Furthermore, we found that prostaglandin E2 (PGE2) plays a crucial role in PDLSCs-mediated immunomodulation and periodontal tissue regeneration in vitro and in vivo. Our study demonstrated that PDLSCs possess low immunogenicity and marked immunosuppression via PGE2-induced T-cell anergy. We developed a standard technological procedure of using allogeneic PDLSCs to cure periodontitis in swine.
Structural abnormalities revealed by magnetic resonance imaging in rats prenatally exposed to methylazoxymethanol acetate parallel cerebral pathology in schizophrenia
Authors: Chin Chih‐Liang , Curzon Peter , Schwartz Annette J. , O'Connor Elizabeth M. , Rueter Lynne E. , Fox Gerard B. , Day Mark , Basso Ana M.
Published: August 2010

Schizophrenia is a highly familial, neurodevelopmental disorder that is associated with several neuropsychiatric, psychological, and neuropathological features. Although pharmacological animal models of dopaminergic and glutamatergic dysfunction have helped advance our understanding of the disease biology, there is a clear need for translational models that capture the neuropathological and functional manifestations associated with the intermediate phenotype and the clinical illness. Neuroimaging of preclinical neurodevelopmental approaches such as methylazoxymethanol acetate (MAM) exposure may afford a powerful translational tool to establish endpoints with greater congruency across animals and humans. Using in vivo volumetric magnetic resonance imaging (MRI), manganese‐enhanced MRI, and diffusion tensor imaging (DTI), we investigated morphological and cytoarchitectural changes of brain structures in MAM‐exposed rats, a neurodevelopmental model of schizophrenia. Compared to saline‐exposed controls, MAM‐exposed rats showed significant enlargement of lateral and third ventricles as well as reduced hippocampal volumes, which is consistent with findings observed in schizophrenia. In addition, DTI revealed that diffusion fractional anisotropy retrieved from corpus callosum and cingulum were significantly decreased in MAM‐exposed rats, suggesting that demyelination occurred in these white‐matter fiber tracts. Imaging findings were confirmed by conducting histological analysis using hematoxylin and eosin and Luxol fast blue stainings. In summary, structural abnormalities resulting from a MAM environmental challenge parallel cerebral pathology observed in schizophrenia. The MAM model incorporating noninvasive imaging techniques may therefore serve as an improved translational research tool for assessing new treatments for schizophrenia. Synapse, 2010. © 2010 Wiley‐Liss, Inc.
BSiZer
Authors: Holmström Lasse
Published: August 2010

BSiZer is a smoothing‐based Bayesian data analysis tool that can be used to find scale‐dependent features in scatter plots. It uses a scale space approach which means that, instead of just one smooth, a whole family of smoothing levels are explored, with each level thought to describe the object of interest at a particular scale or resolution. While the original BSiZer was used to analyze curves underlying noisy data, we discuss also its subsequent extensions to the analysis of images and random fields. The methodology is demonstrated with applications to climate reconstruction and prediction and image analysis. © 2010 John Wiley & Sons, Inc.

This article is categorized under:

Statistical Learning and Exploratory Methods of the Data Sciences > Knowledge Discovery
On the predictability of zero‐stiffness postbuckling
Authors: Mang H.A. , Höfinger G. , Jia X.
Published: August 2010

The purpose of this paper is to derive sufficient and necessary conditions for zero‐stiffness postbuckling which is bound up with a favorable form of transition from imperfection sensitivity to imperfection insensitivity in the course of sensitivity analysis of the initial postbuckling path. Zero‐stiffness postbuckling as such is shown to be imperfection insensitive. Choosing Koiter's initial postbuckling analysis as the vehicle for answering the question of predictability of zero‐stiffness postbuckling seems, at first sight, to be a contradiction in terms, since zero‐stiffness postbuckling includes the entire postbuckling path whereas Koiter's initial postbuckling analysis is practically restricted to the neighborhood of the bifurcation point. The theoretical findings presented in this work are verified numerically.
Craniella sputnika sp. nov. (Porifera: Spirophorida: Tetillidae) from the Aleutian Islands, Alaska, with suggested nomenclatural changes for the genera Tetilla and Craniella
Authors: Lehnert Helmut , Stone Robert P.
Published: August 2010

A new species of Craniella from the Aleutian Islands is described. Craniella sputnika sp. nov. differ from all other species of Craniella in its habitus, absence of microscleres and size of spicules. The name refers to its resemblance to Earth's first artificial satellite, due to its spherical body with long spines. The new species was observed growing on another demosponge, Myxilla sp. We propose transferring two species currently in Craniella to Tetilla (Craniella ellipsoidea Hoshino, 1982 and Craniella laminaris (George & Wilson, 1919)) and two subspecies (Craniella globosa anamonaena Tanita, 1968 and Craniella laminaris symmetrica (Wilson, 1931)) from Craniella to Tetilla. As Craniella globosa anamonaena Tanita, 1968, is actually a species of Tetilla we suggest raising the subspecies to species rank as Tetilla anamonaena. Conversely we think that two species, Tetilla ovata (Thiele, 1898) and Tetilla hamatum Koltun, 1966 should be transferred to Craniella.
The Making and Remaking of a Chinese Hospital in Hong Kong
Authors: MA SHU-YUN
Published: August 2010

Hong Kong's hospital system has long been the territory of Western medicine. However, during the Severe Acute Respiratory Syndrome (SARS) outbreak in 2003, an integrative approach, combining Chinese and Western medicines, was used in some hospitals in Hong Kong, suggesting a revival of Chinese medicine in the hospital system of this former British colony. This paper will explain how this could happen, by situating the event in the over 160 years' long history of Chinese medicine in Hong Kong. Specifically, it will focus on the role of ‘Chinese medicine’ and ‘traditional Chinese medicine’ in Tung Wah Hospital, a local charity established in 1870, which grew subsequently into one of the largest voluntary organizations in Hong Kong. It will also show how the fall and revival of Chinese medicine in this hospital were related to two epidemics: the bubonic plague in 1894, and the SARS outbreak in 2003.
A review of early supported discharge after stroke
Authors: Brewer Linda , Williams David
Published: August 2010

Stroke is a leading cause of disability worldwide and patients with stroke frequently require prolonged periods of in-patient rehabilitation prior to discharge. This poses a large economic strain on health services, and the cost-effectiveness of this system has been questioned. However, in implementing changes in the delivery of post-acute stroke care it is important that patient outcome is not compromised. Early supported discharge (ESD) was introduced approximately 15 years ago and allows suitable patients to be discharged home early with increased support from a well co-ordinated, multi-disciplinary rehabilitation team in the patient's own home. This paper focuses upon the evidence available from multiple international studies of ESD over the last decade, including both clinical benefit and cost-effectiveness. Findings from these trials are largely positive resulting from a reduction in bed days, therefore overall cost, and an improvement in function and independence reported in many studies. Suitable patient selection, careful discharge planning and continuity of care by the ESD linked to a stroke unit are essential components of the success of this service.
Scanning Electron and Confocal Scanning Laser Microscopy Imaging of the Ultrastructure and Viability of Vaginal Candida albicans and Non-Albicans Species Adhered to an Intrauterine Contraceptive Device
Authors: Paiva Luciene C. Farias , Donatti Lucélia , Patussi Eliana V. , Svizdinski Terezinha I.E. , Lopes-Consolaro Márcia E.
Published: August 2010

Although bacterial biofilms have been studied in detail, adhesion of Candida albicans and non-albicans species to an intrauterine contraceptive device (IUD) is not clear. The objective of this study was to evaluate aspects of imaging of the ultrastructure and viability of vaginal yeasts adhered to different parts of an IUD, through scanning electron microscopy (SEM) and confocal scanning laser microscopy (CSLM). We studied yeasts isolated from different patients with vulvovaginal candidiasis: C. albicans, C. glabrata, C. guillermondii, C. parapsilosis, C. tropicalis, and Saccharomyces cerevisiae. A suspension of the each yeast was prepared and incubated with IUD parts (tail, without copper, and copper-covered). SEM and CSLM showed that all the vaginal yeasts adhered to all the parts of the IUD and demonstrated viability, including 30 days after contact for C. albicans. Possibly irregularities of IUD surface contribute to the adherence process. Although all of the IUD parts contribute to retention of yeasts in the genital tract, high concentration of yeast cells on the tail may indicate the importance of this segment in maintaining the colonization by yeast cells because the tail forms a bridge between the external environment, the vagina that is colonized by yeast cells, and the upper genital tract where there is no colonization.
Suberized Cell Walls of Cork from Cork Oak Differ from Other Species
Authors: Teixeira Rita Teresa , Pereira Helena
Published: August 2010

Plants have suberized cells that act as protective interfaces with the environment or between different plant tissues. A lamellar structure of alternating dark and light bands has been found upon transmission electron microscopy (TEM) observation of cork cells and considered a typical feature of the suberized secondary wall. We observed cork cells from periderms ofQuercus suber,Quercus cerris, Solanum tuberosum, andCalotropis proceraby TEM after uranyl acetate and lead citrate staining. A lamellated structure was observed inS. tuberosumandC. procerabut not inQ. suberandQ. cerriswhere the suberized cell wall showed a predominantly hyaline aspect with only a dark dotted staining. Removal of suberin fromQ. subercells left a thinner secondary wall that lost the translucent aspect. We hypothesize that the species' specific chemical composition of suberin will result in different three-dimensional macromolecular development and in a different spatial location of lignin and other aromatics. A lamellated ultrastructure is therefore not a general feature of suberized cells.
Viscoplastic flow in migmatites deduced from fabric anisotropy: An example from the Naxos dome, Greece
Authors: Kruckenberg Seth C. , Ferré Eric C. , Teyssier Christian , Vanderhaeghe Olivier , Whitney Donna L. , Seaton Nicholas C. A. , Skord Justin A.
Published: August 2010

Many migmatites represent crystallized partially molten crust and therefore record the mechanisms and pathways of orogenic crustal flow. Field and microstructural methods may be insufficient to characterize the planar and linear elements of rock fabric in migmatites due to obscured flow fabrics or protracted deformation. In the Naxos dome (Greece), we test the anisotropy of magnetic susceptibility (AMS) as a tool for recovering mineral fabric symmetry and the kinematic axes of flow in migmatites. Measurements of 155 migmatite samples yield dominantly low values (<300 × 10−6[SI]) of bulk magnetic susceptibility (Km) consistent with biotite being the dominant carrier of the AMS. Higher values of Km, thermomagnetic, hysteresis, and microstructural data, however, suggest a ferromagnetic contribution from magnetite in a subset of samples (N = 15). Using electron backscatter diffraction (EBSD) analysis, we establish the correspondence of the biotite subfabric with the AMS and structural fabric of the Naxos migmatites. EBSD data from biotite suggests that magnetic lineation in these dominantly paramagnetic migmatites arises from a zone axis orientation of biotite crystals organized about the direction of viscoplastic flow. Over a range of spatial scales, migmatitic foliation and magnetic foliation are well correlated. The magnetic lineation recovered by AMS displays a coherent organization despite the heterogeneous structure and composition of the Naxos migmatites. These data suggest that the apparent complexity of migmatites masks a simpler flow regime controlled by bulk viscoplastic flow. Furthermore, our study demonstrates the utility of the AMS method for studying the dynamics of partially molten orogenic crust.
A model for wet aggregation of ash particles in volcanic plumes and clouds: 1. Theoretical formulation
Authors: Costa Antonio , Folch Arnau , Macedonio Giovanni
Published: August 2010

We develop a model to describe ash aggregates in a volcanic plume. The model is based on a solution of the classical Smoluchowski equation, obtained by introducing a similarity variable and a fractal relationship for the number of primary particles in an aggregate. The considered collision frequency function accounts for different mechanisms of aggregation, such as Brownian motion, ambient fluid shear, and differential sedimentation. Although model formulation is general, here only sticking efficiency related to the presence of water is considered. However, the different binding effect of liquid water and ice is discerned. The proposed approach represents a first compromise between the full description of the aggregation process and the need to decrease the computational time necessary for solving the full Smoluchowski equation. We also perform a parametric study on the main model parameters and estimate coagulation kernels and timescales of the aggregation process under simplified conditions of interest in volcanology. Further analyses and applications to real eruptions are presented in the companion paper by Folch et al.
Lightning electromagnetic fields at very close distances associated with lightning strikes to the Gaisberg tower
Authors: Mosaddeghi A. , Shoory A. , Rachidi F. , Diendorfer G. , Pichler H. , Pavanello D. , Rubinstein M. , Zweiacker P. , Nyffeler M.
Published: August 2010

In this paper we present and discuss measurements of electric (vertical and radial) and magnetic fields from leaders and return strokes associated with lightning strikes to the 100 m tall Gaisberg tower in Austria obtained in 2007 and 2008. The fields were measured at a distance of about 20 m from the tower. Simultaneously, return stroke currents were also measured at the top of the tower. The data include, for the first time at such close distances, simultaneous records of vertical and horizontal electric fields. The vertical electric field waveforms appeared as asymmetrical V‐shaped pulses. The initial, relatively slow, negative electric field change is due to the downward leader, and the following, fast, positive electric field change is due to the upward return stroke phase of the lightning discharge. The horizontal (radial) electric field due to the leader phase has a waveshape similar to that of the vertical electric field. However, the horizontal field due to the return stroke is characterized by a short negative pulse of the order of 1μs or so, starting with a fast negative excursion followed by a positive one. The return stroke vertical electric field changes appear to be significantly smaller than similar measurements obtained using triggered lightning. This finding confirms the shadowing effect of the tower, which results in a significant decrease of the electric field at distances of about the height of the tower or less. The vertical and horizontalEfield changes due to the return stroke were also found to be larger on average than the leader electric field changes. In a significant number of cases (33%), the vertical electric field waveforms due to the return stroke were characterized by a first peak exceeding the typical late‐time flattening due to the electrostatic term. This is in contrast with similar measurements related to triggered lightning which do not exhibit such a first peak. About one quarter of the measured vertical electric field waveforms (18 pulses out of 76) featured an unusual waveform characterized by a positive leader field change followed by a bipolar return stroke field change with a zero crossing time of about 60μs.
Catalyzing Interdisciplinary Research on Climate Change: DISCCRS: Dissertations Initiative for the Advancement of Climate Change Research; Mesa, Arizona, 13–20 March 2010
Authors: Marlon Jennifer R. , Patenaude Genevieve , Barnes Rebecca T.
Published: August 2010

Each year, the Dissertations Initiative for the Advancement of Climate Change Research (DISCCRS; http://disccrs.org) brings together a select group of 34 recent Ph.D. graduates to facilitate peer networking and professional development and to encourage interdisciplinary research related to climate change. This year, the invited scholars included physical, biological, and social scientists specializing in fields ranging from atmospheric science to environmental governance. The meeting focused on the challenges and benefits of collaborative interdisciplinary research and the imperative to achieve climate change solutions. Professional development activities provided participants with new tools for scientific communication, leadership, and facilitation of collaboration. The symposium demonstrated the value of interacting in an intensive, structured setting with a highly diverse group around a shared scientific interest.
Non‐detection of impulsive radio signals from lightning in Martian dust storms using the radar receiver on the Mars Express spacecraft
Authors: Gurnett D. A. , Morgan D. D. , Granroth L. J. , Cantor B. A. , Farrell W. M. , Espley J. R.
Published: August 2010

Here we report the results of a nearly five‐year search for impulsive radio signals from lightning discharges in Martian dust storms using the radar receiver on the Mars Express spacecraft. The search covered altitudes from 275 km to 1400 km and frequencies from 4.0 to 5.5 MHz with a time resolution of 91.4 μs and a detection threshold of 2.8 × 10−18 Watts m−2 Hz−1. At comparable altitudes the intensity of terrestrial lightning is several orders of magnitude above this threshold. Although two major dust storms and many small storms occurred during the search period, no credible detections of radio signals from lightning were observed.
Constraints on black carbon aerosol distribution from Measurement of Pollution in the Troposphere (MOPITT) CO
Authors: Arellano Avelino F. , Hess Peter G. , Edwards D. P. , Baumgardner D.
Published: August 2010

We present an approach to constrain simulated atmospheric black carbon (BC) using carbon monoxide (CO) observations. The approach uses: (1) the Community Atmosphere Model with Chemistry to simulate the evolution of BC and CO within an ensemble of model simulations; (2) satellite CO retrievals from the MOPITT/Terra instrument to assimilate observed CO into these simulations; (3) the derived sensitivity of BC to CO within these simulations to correct the simulated BC distributions. We demonstrate the performance of this approach through model experiments with and without the BC corrections during the period coinciding with the Intercontinental Chemical Transport Experiment (INTEX‐B). Our results show significant improvements (∼50%) in median BC profiles using constraints from MOPITT, based on comparisons with INTEX‐B measurements. We find that assimilating MOPITT CO provides considerable impact on simulated BC concentrations, especially over source regions. This approach offers an opportunity to augment our current ability to predict BC distributions.
Managing academic research
Authors: van Helden Paul
Published: August 2010

Paul van Helden argues that the waxing of research management undermines scientists’ power to make decisions. Researchers should take a firmer stand against the creeping administration of research before it threatens their work.
Bystander inhibition of dendritic cell differentiation by Mycobacterium tuberculosis‐induced IL‐10
Authors: Remoli Maria Elena , Giacomini Elena , Petruccioli Elisa , Gafa Valerie , Severa Martina , Gagliardi Maria Cristina , Iona Elisabetta , Pine Richard , Nisini Roberto , Coccia Eliana Marina
Published: August 2010

Mycobacterium tuberculosis (Mtb) evades the immune response by impairing the functions of different antigen‐presenting cells. We have recently shown that Mtb hijacks differentiation of monocytes into dendritic cells (DCs). To further characterize the mechanisms underlying this process, we investigated the consequences of inducing dendritic cell differentiation using interferon‐α and granulocyte‐macrophage colony‐stimulating factor in the presence of supernatants (SNs) obtained from monocyte cultures treated with or without heat‐inactivated Mtb. Although the SNs from control cultures do not interfere with the generation of fully differentiated DCs, monocytes stimulated with SNs from Mtb‐stimulated cells (SN Mtb) remained CD14+ and poorly differentiated into CD1a+ cells. Among cytokines known to affect dendritic cell differentiation, we observed a robust production of interleukin‐1β, interleukin‐6, interleukin‐10 and tumor necrosis factor‐α upon Mtb stimulation. However, only interleukin‐10 neutralization through the addition of soluble interleukin‐10 receptor reversed the inhibitory activity of SN Mtb. Accordingly, the addition of recombinant interleukin‐10 was able to significantly reduce CD1a expression. The interaction of Mtb with differentiating monocytes rapidly activates p38 mitogen‐activated protein kinase, signal transducer and activator of transcription pathways, which are likely involved in interleukin‐10 gene expression. Taken together, our results suggest that Mtb may inhibit the differentiation of bystander non‐infected monocytes into DCs through the release of interleukin‐10. These results shed light on new aspects of the host–pathogen interaction, which might help to identify innovative immunological strategies to limit Mtb virulence.
Thermal expansion of thermoelectric type-I-clathrates
Authors: Falmbigl M. , Rogl G. , Rogl P. , Kriegisch M. , Müller H. , Bauer E. , Reinecker M. , Schranz W.
Published: August 2010

Thermal expansion was determined for two series of ternary compounds, Ba8MxGe46−x and Ba8MxSi46−x, with M=Cu, Zn, Pd, Ag, Cd, Pt, and Au and for several quaternary compounds for which we investigated the influence of substitution by Zn/Ni in Ba8ZnxGe46−x as well as the dependence of thermal expansion on the Si/Ge ratio in Ba8Cu5SixGe41−x. In the temperature range from 4.2 to 300 K the thermal expansion of all ternary compounds was measured with a capacitance dilatometer, whereas from 300 to 700 K for several selected samples a dynamic mechanical analyzer was employed. The low temperature data compare well with the lattice parameters of single crystals, gained from measurements at three different temperatures (100, 200, and 300 K). For a quantitative description of thermal expansion the semiclassical model of Mukherjee et al. [Phys. Rev. Lett. 76, 1876 (1996)] was used, which also provided reliable accurate values of the Debye and Einstein temperatures. Results in this respect show good agreement with the corresponding data derived from temperature dependent x-ray diffraction and specific heat measurements. Furthermore the present paper is a comprehensive collection and discussion of all thermal expansion data of intermetallic type-I-clathrate materials so far available in the literature including our results of thermal expansion measurements of the Ge- and Si-based type-I-clathrates listed above.
Global and local Voronoi analysis of solvation shells of proteins
Authors: Neumayr Gregor , Rudas Tibor , Steinhauser Othmar
Published: August 2010

This paper presents the structure and dynamics of hydration shells for the three proteins: ubiquitin, calbindin, and phospholipase. The raw data derived from molecular dynamics simulations are analyzed on the basis of fully atomistic Delaunay tesselations. In order to cope with the high numerical effort for the computation of these Voronoi shells, we have implemented and optimized an intrinsically periodic algorithm. Based on this highly efficient Voronoi decomposition, a variety of properties is presented: three dimensional water and ion nuclear densities as well as the geometrical packing of water molecules are discussed. Thereby, we develop Voronoi interface surface area, the Voronoi analog of the well known solvent accessible surface area. The traditional radial distribution functions are resolved into Voronoi shells as a transient device to the new concept of shell-grained orientational order. Thus, we analyze the donor-acceptor property as well as the amount of dielectric screening. Shell dynamics is described in terms of mean residence times. In this way, a retardation factor for different shells can be derived and was compared to experimental values. All these results and properties are presented both at the global protein level as well as at the local residue level.
Real space mapping of polarization dynamics and hysteresis loop formation in relaxor-ferroelectric PbMg1/3Nb2/3O3–PbTiO3 solid solutions
Authors: Rodriguez B. J. , Jesse S. , Morozovska A. N. , Svechnikov S. V. , Kiselev D. A. , Kholkin A. L. , Bokov A. A. , Ye Z.-G. , Kalinin S. V.
Published: August 2010

Polarization switching in ergodic relaxor and ferroelectric phases in the PbMg1/3Nb2/3O3–PbTiO3 (PMN-PT) system is studied using piezoresponse force microscopy, single point electromechanical relaxation measurements, and voltage spectroscopy mapping. The dependence of relaxation behavior on voltage pulse amplitude and time is found to follow a universal logarithmic behavior with a nearly constant slope. This behavior is indicative of the progressive population of slow relaxation states, as opposed to a linear relaxation in the presence of a broad relaxation time distribution. The role of relaxation behavior, ferroelectric nonlinearity, and the spatial inhomogeneity of the tip field on hysteresis loop behavior is analyzed in detail. The hysteresis loops for ergodic PMN-10%PT are shown to be kinetically limited, while in PMN with larger PT content, true ferroelectric hysteresis loops with low nucleation biases are observed.
Analysis of the degradation induced by focused ion Ga3+ beam for the realization of piezoelectric nanostructures
Authors: Rémiens D. , Liang R. H. , Soyer C. , Deresmes D. , Troadec D. , Quignon S. , Da Costa A. , Desfeux R.
Published: August 2010

Piezoelectric nanostructures (islands of dimensions in the lateral size range 50–500 nm) have been fabricated by focused Ga3+ ion beam (FIB) etching on PbZr0.54Ti0.46O3 thin films obtained by magnetron sputtering. The degradation induced by the etching process is investigated through the evolution of electromechanical activity measured by means of local piezoelectric hysteresis loops produced by piezoresponse force microscopy. The analysis of surface potential is performed by kelvin force microscopy and the measurement of current-voltage curves is carried out by conducting atomic force microscopy. Two kinds of structures, namely one based on crystallized films and the other based on amorphous ones, were studied. In this latter case, the amorphous films are postannealed after etching to obtain crystallized structure. For the structures based on the crystallized and then etched films, no piezoelectric signal was registered that evidences a serious degradation of material induced by Ga3+ ion implantation. For the structures based on the films etched in amorphous state and then crystallized, the piezoresponse signal was near to that of the reference films (crystallized and not etched) whatever were the ion dose and the island dimensions. Even for very small lateral size (50 nm), no size effect was observed. The island shapes fabricated by Ga3+ FIB etching process (islands with less than 50 nm lateral size) show a limitation of FIB processing and electron beam lithography seems to be necessary.
Optical constants of graphene measured by spectroscopic ellipsometry
Authors: Weber J. W. , Calado V. E. , van de Sanden M. C. M.
Published: August 2010

A mechanically exfoliated graphene flake (∼150×380 μm2) on a silicon wafer with 98 nm silicon dioxide on top was scanned with a spectroscopic ellipsometer with a focused spot (∼100×55 μm2) at an angle of 55°. The spectroscopic ellipsometric data were analyzed with an optical model in which the optical constants were parameterized by B-splines. This parameterization is the key for the simultaneous accurate determination of the optical constants in the wavelength range 210–1000 nm and the thickness of graphene, which was found to be 3.4 Å.
Spatial sensitivity mapping of Hall crosses using patterned magnetic nanostructures
Authors: Alexandrou M. , Nutter P. W. , Delalande M. , de Vries J. , Hill E. W. , Schedin F. , Abelmann L. , Thomson T.
Published: August 2010

Obtaining an accurate profile of the spatial sensitivity of Hall cross structures is crucial if such devices are to be used to analyze the switching behavior of magnetic nanostructures and determine the switching field distribution of bit patterned media. Here, we have used the anomalous Hall effect to investigate the switching of patterned Co/Pt multilayer magnetic nanoislands, where the Hall cross has been integrated into the Pt seed layer. Using the anomalous Hall output voltage we have observed the magnetic switching of individual islands, allowing the spatial sensitivity across a Hall cross structure to be determined. The experimental results agree well with numerical simulation studies, using a three-dimensional finite element model, and with existing theoretical studies, where the spatial sensitivity of two-dimensional Hall cross structures have been found numerically.
Image processing with cellular nonlinear networks implemented on field-programmable gate arrays for real-time applications in nuclear fusion
Authors: Palazzo S. , Murari A. , Vagliasindi G. , Arena P. , Mazon D. , De Maack A. ,   JET-EFDA Contributors
Published: August 2010

In the past years cameras have become increasingly common tools in scientific applications. They are now quite systematically used in magnetic confinement fusion, to the point that infrared imaging is starting to be used systematically for real-time machine protection in major devices. However, in order to guarantee that the control system can always react rapidly in case of critical situations, the time required for the processing of the images must be as predictable as possible. The approach described in this paper combines the new computational paradigm of cellular nonlinear networks (CNNs) with field-programmable gate arrays and has been tested in an application for the detection of hot spots on the plasma facing components in JET. The developed system is able to perform real-time hot spot recognition, by processing the image stream captured by JET wide angle infrared camera, with the guarantee that computational time is constant and deterministic. The statistical results obtained from a quite extensive set of examples show that this solution approximates very well an ad hoc serial software algorithm, with no false or missed alarms and an almost perfect overlapping of alarm intervals. The computational time can be reduced to a millisecond time scale for 8 bit 496×560-sized images. Moreover, in our implementation, the computational time, besides being deterministic, is practically independent of the number of iterations performed by the CNN—unlike software CNN implementations.
System for time resolved spectral studies of pulsed atmospheric discharges in the visible to vacuum ultraviolet range
Authors: Laity G. , Neuber A. , Rogers G. , Frank K.
Published: August 2010

Vacuum ultraviolet (VUV) emission is believed to play a major role in the development of plasma streamers in pulsed atmospheric discharges, but detection of VUV light is difficult in pulsed experiments at atmospheric pressures. Since VUV light is absorbed in most standard optical materials as well, careful attention must be given to the selection of the lens and mirror optics used in these studies. Of highest interest is the VUV emission during the initial stage of pulsed atmospheric discharges, which has a typical duration in the nanosecond regime. An experiment was designed to study this fast initial stage of VUV emission coupled with fast optical imaging of streamer propagation, both with temporal resolution on the order of nanoseconds. A repetitive solid-state high voltage pulser was constructed which produces triggered flashover discharges with low jitter and consistent pulse amplitude. VUV emission is captured utilizing both photomultiplier and intensified charge-coupled device detectors during the fast stage of streamer propagation. These results are discussed in context with the streamer formation photographed in the visible wavelength regime with 3 ns exposure time.
Renner–Teller intersections along the collinear axes of polyatomic molecules: H2CN as a case study
Authors: Das Anita , Mukhopadhyay Debasis , Adhikari Satrajit , Baer Michael
Published: August 2010

The tetra-atomic C2H2+ cation is known to form Renner–Teller-type intersections along its collinear axis. Not too long ago, we studied the nonadiabatic coupling terms (NACTs) of this molecule [G. J. Halász et al., J. Chem. Phys. 126, 154309 (2007)] and revealed two kinds of intersections. (i) By employing one of the hydrogens as a test particle, we revealed the fact that indeed the corresponding (angular) NACTs produce topological (Berry) phases that are equal to 2π, which is a result anticipated in the case of Renner–Teller intersections. (ii) However, to our big surprise, repeating this study when one of the atoms (in this case a hydrogen) is shifted from the collinear arrangement yields for the corresponding topological phase a value that equals π (and not 2π). In other words, shifting (even slightly) one of the atoms from the collinear arrangement causes the intersection to change its character and become a Jahn–Teller intersection. This somewhat unexpected novel result was later further analyzed and confirmed by other groups [e.g., T. Vertesi and R. Englman, J. Phys. B 41, 025102 (2008)]. The present article is devoted to another tetra-atomic molecule, namely, the H2CN molecule, which just like the C2H2+ ion, is characterized by Renner–Teller intersections along its collinear axis. Indeed, we revealed the existence of Renner–Teller intersections along the collinear axis, but in contrast to the C2H2+ case a shift of one atom from the collinear arrangement did not form Jahn–Teller intersections. What we found instead is that the noncollinear molecule was not affected by the shift and kept its Renner–Teller character. Another issue treated in this article is the extension of (the two-state) Berry (topological) phase to situations with numerous strongly interacting states. So far the relevance of the Berry phase was tested for systems characterized by two isolated interacting states, although it is defined for any number of interacting states [M. V. Berry, Proc. R. Soc. London, Ser. A 392, 45 (1984)]. We intend to show how to overcome this limitation and get a valid, fully justified definition of a Berry phase for an isolated system of any number of interacting states (as is expected).
Formation of low-resistance Ohmic contacts to N-face n-GaN for high-power GaN-based vertical light-emitting diodes
Authors: Jeon Joon-Woo , Park Seong-Han , Jung Se-Yeon , Lee Sang Youl , Moon Jihyung , Song June-O , Seong Tae-Yeon
Published: August 2010

We report on the formation of low-resistance Ohmic contacts to N-face n-GaN for high-power vertical light-emitting diodes using an Al–Ga solid solution (50 nm)/Ti(30 nm)/Al(200 nm) scheme and compare them with Ti(30 nm)/Al(200 nm) contacts. The Al–Ga solid solution layer is introduced to minimize the formation of Ga vacancies near the N-face n-GaN surface. It is shown that, unlike the Ti/Al contacts, the Al–Ga solid solution/Ti/Al contacts exhibit Ohmic behavior with a resistivity of 4.1×10−4 Ω cm2, even after annealing at 250 °C. X-ray photoemission spectroscopy and secondary ion mass spectrometry examinations are performed to understand the temperature dependence of the electrical properties.
Impacts of red meat production on biodiversity in Australia: a review and comparison with alternative protein production industries
Authors: Williams J. E. , Price R. J.
Published: August 2010

All food production systems are under pressure to comply with societal expectations that the produce is not only of good nutritional value but is also sustainably produced. This review compares the performance of the red meat industry in Australia against white meat, plant-protein and other protein production systems across a range of biodiversity pressures through a review of over 500 peer-reviewed and other scientific sources. The review finds that taking into account the past legacy of red meat production systems, these industries make the largest relative potential contribution to the impact on terrestrial biodiversity in Australia, by both the area covered and the nature of the impacts. The review also finds that many initiatives of the beef and sheep industries have the potential to improve the management of biodiversity. To minimise the impact of beef and sheep meat systems on biodiversity, the conservation of natural resources needs to become a core and integral part of production systems, rather than it being perceived as an optional extra if times are good. To help address these challenges, stewardship payments for the ecosystem services (such as carbon, water and biodiversity) provided by the farming community to the wider society warrant further consideration.