bluuebunny/crossref_metadata_2025 huggingface dataset:
Mesenchymal Lineage Stem Cells Have Pronounced Anti-Inflammatory Effects in the Twitcher Mouse Model of Krabbe's Disease
Authors: Ripoll Cynthia B. , Flaat Mette , Klopf-Eiermann Jessica , Fisher-Perkins Jeanne M. , Trygg Cynthia B. , Scruggs Brittni A. , McCants Marjorie L. , Leonard Helen Paige , Lin Amy F. , Zhang Shijia , Eagle Michelle E. , Alvarez Xavier , Li Yu Teh , Li Su Chen , Gimble Jeffrey M. , Bunnell Bruce A.
Published: November 2010

The twitcher mouse is an animal model of Krabbe's disease (KD), which is a neurodegenerative lysosomal storage disorder resulting from the absence of functional lysosomal enzyme galactocerebrosidase (GALC). This disease affects the central and peripheral nervous systems and in its most severe form results in death before the age of 2 in humans and approximately 30–40 days in mice. This study evaluates the effect of intracerebroventricular administration of mesenchymal stem cells derived from adipose tissue (ASCs) and bone marrow (BMSCs) on the pathology of KD. Subsequent to the intracerebroventricular injection of ASCs or BMSCs on postnatal day (PND) 3–4, body weight, lifespan, and neuromotor function were evaluated longitudinally beginning on PND15. At sacrifice, tissues were harvested for analysis of GALC activity, presence of myelin, infiltration of macrophages, microglial activation, inflammatory markers, and cellular persistence. Survival analysis curves indicate a statistically significant increase in lifespan in stem cell-treated twitcher mice as compared with control twitcher mice. Body weight and motor function were also improved compared with controls. The stem cells may mediate some of these benefits through an anti-inflammatory mechanism because the expression of numerous proinflammatory markers was downregulated at both transcriptional and translational levels. A marked decrease in the levels of macrophage infiltration and microglial activation was also noted. These data indicate that mesenchymal lineage stem cells are potent inhibitors of inflammation associated with KD progression and offer potential benefits as a component of a combination approach for in vivo treatment by reducing the levels of inflammation.
Validation of reference tissue model of PET ligand [11C](+)3‐MPB for the muscarinic cholinergic receptor in the living brain of conscious monkey
Authors: Yamamoto Shigeyuki , Ohba Hiroyuki , Nishiyama Shingo , Takahashi Kazuhiro , Tsukada Hideo
Published: November 2010

N‐[11C]Methyl‐3‐piperidyl benzilate ([11C](+)3‐MPB) was developed as a positron emission tomography (PET) ligand for muscarinic cholinergic receptor (mAChR). The aim of the present study was to validate a Logan reference tissue method as an analytical method for in vivo binding of [11C](+)3‐MPB to mAChR. Seven monkeys (Macaca mulatta) underwent [11C](+)3‐MPB PET scans with an arterial blood sampling. Logan plot with arterial input function (Logan arterial input method) was performed to determine the binding potential (BPND). The BPNDwas also determined by Logan plot with the cerebellum as the reference region (Logan reference tissue method). BPNDvalues determined by Logan arterial input method and Logan reference tissue method showed a significant linear relationship. The present study suggests that the cerebellum is a suitable reference region for quantification of mAChR in the living brain with [11C](+)3‐MPB and PET. Synapse, 2011. © 2010 Wiley‐Liss, Inc.
Association between ultrasound‐based assessment of fetal head station and clinically assessed cervical dilatation
Authors: Haberman S. , Paltieli Y. , Gonen R. , Ohel G. , Ville Y. , Nizard J.
Published: November 2010

Objectives

To describe the association between ultrasound‐based determination of fetal head station and clinical assessment of cervical dilatation during active labor.

Methods

From 427 women with singleton uncomplicated term pregnancies we obtained, during the active phase of labor, 907 pairs of measurements. Fetal head station and position were determined using the LaborPro system, based on position tracking and ultrasound imaging technology, and degree of cervical dilatation was determined by digital vaginal examination. The association between them was analyzed.

Results

The overall correlation between cervical dilatation and fetal head station was 0.64 (P < 0.001). Complete dilatation was observed in 78% of women with fetal head engagement, and in all women with a fetal head station of + 1.5 or more.

Conclusions

There is good association between non‐invasive ultrasound‐based determination of fetal head station and clinically assessed cervical dilatation. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Public engagement with large‐scale renewable energy technologies: breaking the cycle of NIMBYism
Authors: Devine‐Wright Patrick
Published: November 2010

In response to the threat of climate change, many governments have set policy goals to rapidly and extensively increase the use of renewable energy in order to lessen reliance upon fossil fuels and reduce emissions of greenhouse gases. Such policy goals are ambitious, given past controversies over large‐scale renewable energy projects, particularly onshore wind farms, that have occurred in many countries and involved bitter disputes between private developers and local ‘NIMBYs’ (not in my backyard) protestors. This article critically reviews recent research into how public engagement is conceived and practiced by policy makers and developers, with a specific focus upon the UK. The review reveals a distinction between different scales of technology deployment, with active public engagement only promoted at smaller scales, and a more passive role promoted at larger scales. This passive role stems from the influence of widely held NIMBY conceptions that presume the public to be an ‘ever present danger’ to development, arising from a deficit in factual knowledge and a surfeit of emotion, to be marginalized through streamlined planning processes and one‐way engagement mechanisms. It is concluded that NIMBYism is a destructive, self‐fulfilling way of thinking that risks undermining the fragile, qualified social consent that exists to increase renewable energy use. Breaking the cycle of NIMBYism requires new ways of thinking and practicing public engagement that better connect national policy making with local places directly affected by specific projects. Such a step would match the radical ambitions of rapid increases in renewable energy use with a process of change more likely to facilitate its achievement. WIREs Clim Change 2011 2 19–26 DOI: 10.1002/wcc.89

This article is categorized under:

Perceptions, Behavior, and Communication of Climate Change > Behavior Change and Responses
From “Water Boiling in a Peruvian Town” to “Letting them Die”: Culture, Community Intervention, and the Metabolic Balance Between Patience and Zeal
Authors: Trickett Edison J.
Published: November 2010

While the concept of culture has long been central to community psychology research and intervention, it has most frequently referred to the communities in which such work occurs. The purpose of this paper is to reframe this discussion by viewing community interventions as instances of intercultural contact between the culture of science, reflected in community intervention research, and the culture of the communities in which those interventions occur. Following a brief discussion of the complexities of culture as a concept, two illustrative stories of failed community interventions are provided to highlight the centrality of cultural and contextual understanding as prelude to community intervention. These stories, set 50 years apart, reflect the depth and pervasive influence of both the culture of science and the culture of communities. Next, a series of propositions about the culture of social science as a partial reflection of the broader culture of the United States are offered, and their implications for the conduct of community interventions drawn. The paper concludes with a series of recommendations which, together, provide an ecological mind‐set for taking culture seriously in community interventions. Central to this mind set are the importance of focusing on communities rather than programs and emphasizing the intervention goal of choice over change.
A Sandwich-Type Standard Error Estimator of SEM Models with Multivariate Time Series
Authors: Zhang Guangjian , Chow Sy-Miin , Ong Anthony D.
Published: November 2010

Structural equation models are increasingly used as a modeling tool for multivariate time series data in the social and behavioral sciences. Standard error estimators of SEM models, originally developed for independent data, require modifications to accommodate the fact that time series data are inherently dependent. In this article, we extend a sandwich-type standard error estimator of independent data to multivariate time series data. One required element of this estimator is the asymptotic covariance matrix of concurrent and lagged correlations among manifest variables, whose closed-form expression has not been presented in the literature. The performance of the adapted sandwich-type standard error estimator is evaluated using a simulation study and further illustrated using an empirical example.
Effects of changing dietary fat content on plasma gut hormone concentrations in diet-induced obese and diet-resistant rats
Authors: Li Jie , Wang Shuran , Zhang Na , Li Ze , Li Rui , Li Cong
Published: November 2010

Gut hormones play key roles in the regulation of energy homeostasis. However, little is known about the long- and short-term effects of changing dietary fat content on gut hormones. We aim to examine the effects of changing dietary fat content on plasma gut hormone concentrations in diet-induced obese (DIO) and diet-resistant (DR) rats. After inducing obesity with a high-fat (HF) diet, male Sprague–Dawley rats were divided into three groups according to their body-weight gain: DIO; DR; control (CON). The DIO and DR rats were further divided in random into two groups. One continued on a HF diet and the other switched to a low-fat (LF) diet for an additional 4 weeks. Finally, each group was randomly divided into three subgroups (n 8): fasted; fasted-refed HF; fasted-refed LF diet groups. Replacing a HF diet with a LF diet for 4 weeks resulted in less fat mass, higher fasting and post-HF plasma ghrelin concentration and lower postprandial plasma cholecystokinin concentration in the DIO and DR rats. Acute switching dietary fat resulted in significantly higher post-HF plasma ghrelin concentrations than post-LF ghrelin concentrations in the DR rats on LF diet (DRLF) and DIO rats on LF diet (DIOLF) rats, and significantly higher post-HF obestatin concentrations than post-LF obestatin concentrations in the CON, DR rats on HF diet (DRHF) and DRLF rats. Dietary fat content appears to play a role in the gut hormone profile, which may consequently influence fat mass.
Manufacturing process influences properties of probiotic bacteria
Authors: Grześkowiak Łukasz , Isolauri Erika , Salminen Seppo , Gueimonde Miguel
Published: November 2010

Production and manufacturing methods and the food carrier may influence the properties of probiotic strains, and have an impact on the outcome of clinical intervention studies. The aim of the present study was to establish whether the properties of a specific probiotic strain,Lactobacillus rhamnosusGG, may differ depending on the product and source of the strain. In total, fifteen differentL. rhamnosusisolates, among them fourteen labelled asL.rhamnosusGG, were isolated from specific probiotic products. The micro-organisms were phenotypically and genotypically characterised. Their adhesion properties were compared using the human intestinal mucus model, and the ability of the isolates to influence model pathogen adhesion to human colonic mucus was assessed. AllL. rhamnosusisolates used were confirmed as members of the speciesL. rhamnosus. Except the reference strain OL, allL.rhamnosusisolates showed randomly amplified polymorphic DNA, enterobacterial repetitive intergenic consensus and pulsed-field gel electrophoresis profiles identical to that ofL. rhamnosusGG (ATCC 53103). AllL.rhamnosusisolates showed similar tolerance to acid and were able to bind to human colonic mucus. However, pathogen exclusion by inhibition and competition varied significantly among the differentL. rhamnosusisolates and pathogens tested. The results suggest that different sources of the same probiotic may have significantly altered strain properties. This should be considered inin vivostudies on human subjects and also for quality control of probiotic products.
Liberal Leviathan or Imperial Outpost? J. S. Furnivall on Colonial Rule in Burma
Authors: ENGLEHART NEIL A.
Published: November 2010

J. S. Furnivall, in his influential account of the impact of British rule in Burma 1824–1948, argues that British officials laid down a Liberal administration that exposed the colony to market forces, monetized the economy and devastated communities. However, there is little evidence that British administrators actually thought in Liberal terms: they relied heavily on institutions inherited from the Burmese monarchy, and when they introduced new administrative methods these were drawn from other parts of British India and only indirectly influenced by Liberalism. Furnivall's view of the ideological origins of British administration, in turn, distorts his reading of the impact of British rule, as illustrated by recent work on the pre-colonial economy showing that it was in fact more monetized and commercialized than he claims. If his account of the pre-modern economy is not viable, Furnivall's claims about the impact of British colonialism in Burma demand re-evaluation.
Use It and Still Lose It?
Authors: Schwaninger Adrian , Hardmeier Diana , Riegelnig Judith , Martin Mike
Published: November 2010

In recent years, research on cognitive aging increasingly has focused on the cognitive development across middle adulthood. However, little is still known about the long-term effects of intensive job-specific training of fluid intellectual abilities. In this study we examined the effects of age- and job-specific practice of cognitive abilities on detection performance in airport security x-ray screening. In Experiment 1 (N = 308; 24–65 years), we examined performance in the X-ray Object Recognition Test (ORT), a speeded visual object recognition task in which participants have to find dangerous items in x-ray images of passenger bags; and in Experiment 2 (N = 155; 20–61 years) in an on-the-job object recognition test frequently used in baggage screening. Results from both experiments show high performance in older adults and significant negative age correlations that cannot be overcome by more years of job-specific experience. We discuss the implications of our findings for theories of lifespan cognitive development and training concepts.
On the impact of shrub encroachment on microclimate conditions in the northern Chihuahuan desert
Authors: He Yufei , D'Odorico Paolo , De Wekker Stephan F. J. , Fuentes Jose D. , Litvak Marcy
Published: November 2010

Changes in vegetation cover are known for their ability to modify the surface energy balance and near‐surface microclimate conditions. A major change in vegetation composition that has been occurring in many dryland regions around the world is associated with the replacement of arid grasslands by desert shrublands. The impact of shrub encroachment on regional climate conditions remains poorly investigated, and, to date, it is unclear how this shift in plant community composition may affect the microclimate. Here we used concurrent meteorological observations at two adjacent sites dominated by Larrea tridentata shrubs and native grass species, respectively, in the northern Chihuahuan desert to investigate differences in nighttime air temperatures between the shrubland and grassland vegetation covers. The nighttime air temperature was found to be substantially higher (>2°C) in the shrubland than in the grassland, especially during calm winter nights. These differences in surface air temperature were accompanied by differences in longwave radiation and sensible and ground heat fluxes. We developed a one‐dimensional model to show how longwave radiation emitted by the ground at night can explain the higher nighttime air temperature over the shrubland. Because of the larger fraction of bare soil typically existing in the shrub cover, the ground surface remains less insulated and more energy flows into the ground at the shrubland site than in the grassland during daytime. This energy is then released at night mainly as longwave radiation, which causes the differences in the nighttime air temperatures between the two land covers.
On the use of fire radiative power, area, and temperature estimates to characterize biomass burning via moderate to coarse spatial resolution remote sensing data in the Brazilian Amazon
Authors: Schroeder Wilfrid , Csiszar Ivan , Giglio Louis , Schmidt Christopher C.
Published: November 2010

Spaceborne instruments provide a unique view of global vegetation fire activity many times a day. In this study, we assessed the fire characterization information provided by two major products: the Terra and Aqua MODIS Thermal Anomalies product (MOD14 and MYD14, respectively) and the Wildfire Automated Biomass Burning Algorithm (WF_ABBA) product derived from GOES East Imager. Using higher spatial resolution imagery data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Landsat Enhanced Thematic Mapper Plus (ETM+) instruments, we analyzed the characterization of subpixel fires detected by MOD14, MYD14, and WF_ABBA over parts of Brazilian Amazonia. Our results suggest that MODIS and GOES fire radiative power (FRP) estimates derived for individual fire‐pixel clusters are subject to errors due to the effects of the point spread function of those instruments (underestimation of up to 75%), improper fire background characterization (overestimation of up to 80% assuming a 10 K cold bias in background temperature), and omission of small fire lines. Detection limits were approximately 11 and 9 MW for MOD14 and MYD14, respectively, and were equivalent to 27 and 19 MW for WF_ABBA data acquired coincidently with MOD14 and MYD14, respectively. We found a positive correlation between FRP and percentage tree cover indicating that FRP is sensitive to biomass density. Fire area and temperature estimates derived from the application of Dozier's (1981) approach to GOES data did not agree with our reference data (i.e., ASTER and ETM+ active fire masks and in situ fire temperature data), suggesting that large and variable errors could affect the retrieval of those parameters.
AGU Council to Meet in December
Authors: Enderlein Cheryl L.
Published: November 2010

The AGU Council will hold a meeting on Sunday, 12 December 2010, in San Francisco in conjunction with the Fall Meeting. This is the first meeting of the reconfigured Council, chaired by President‐elect Carol Finn. As an outcome of the membership vote a year ago, the composition and the focus of the Council changed. With the creation of the Board of Directors to handle the business and fiduciary responsibilities of the organization, the Council is free to focus on science policy and other science‐related matters.
Predictability of Indian summer monsoon weather during active and break phases using a high resolution regional model
Authors: Taraphdar S. , Mukhopadhyay P. , Goswami B. N.
Published: November 2010

As the active and break phases of Indian monsoon are associated with different large scale background regimes, the predictability of monsoon weather is expected to be different during these phases. In the present study, an ensemble of ‘identical twin’ perturbation experiments are carried out using Weather Research Forecast model at 15 km resolution to demonstrate the predictability of weather during these phases. The initial conditions are taken from the 9 years (2001–2009) control simulations during periods of strong intra‐seasonal oscillations events. The study revealed that the background estimates are different in these two contrasting regimes with more errors in the active phases confined mostly along the monsoon trough region. As a consequence, the predictability of active (break) period is found to be around 4 (10) days. Thus, the rapid (sluggish) error growth indicates that the monsoon weather such as lows are less (more) predictable during active (break) phases.
Quasi‐electrostatic whistler mode wave excitation by linear scattering of EM whistler mode waves from magnetic field‐aligned density irregularities
Authors: Foust F. R. , Inan U. S. , Bell T. , Lehtinen N. G.
Published: November 2010

Recent observations by Starks et al. (2008) from multiple spacecraft suggest that the actual nighttime intensity of VLF transmitter signals in the radiation belts is approximately 20 dB below the level that is assumed in the model developed by Abel and Thorne (1998) and approximately 10 dB below model values during the day. In the present work, we discuss one experimentally established mechanism which might be responsible for some of this intensity discrepancy, linear mode coupling as electromagnetic whistler mode waves propagate through regions containing small‐scale (2–100 m) magnetic field‐aligned plasma density irregularities. The scattering process excites quasi‐electrostatic whistler mode waves, which represents a power loss for the input waves. Although the distribution and amplitude of the irregularities is not well known at present, we construct plausible models in order to use numerical simulations to determine the characteristics of the mode coupling mechanism and the conditions under which the input VLF waves can lose significant power to the excited quasi‐electrostatic whistler mode waves. For short propagation paths of approximately 15 km, the full‐wave model predicts power losses ranging from −3 dB (25% probability) to −7 dB (2% probability). For longer propagation paths of approximately 150 km, the full‐wave model predicts power losses ranging from −4 dB (25% probability) to over −10 dB (2% probability). We conclude that for the irregularity models investigated, the mode coupling mechanism can result in significant power loss for VLF electromagnetic whistler mode waves.
Hot spots of vegetation‐climate feedbacks under future greenhouse forcing in Europe
Authors: Wramneby Anna , Smith Benjamin , Samuelsson Patrick
Published: November 2010

We performed simulations of future biophysical vegetation‐climate feedbacks with a regional Earth System Model, RCA‐GUESS, interactively coupling a regional climate model and a process‐based model of vegetation dynamics and biogeochemistry. Simulated variations in leaf area index and in the relative coverage of evergreen forest, deciduous forest, and open land vegetation in response to simulated climate influence atmospheric state via variations in albedo, surface roughness, and the partitioning of the land‐atmosphere heat flux into latent and sensible components. The model was applied on a ∼50 × 50 km grid over Europe under a future climate scenario. Three potential “hot spots” of vegetation‐climate feedbacks could be identified. In the Scandinavian Mountains, reduced albedo resulting from the snow‐masking effect of forest expansion enhanced the winter warming trend. In central Europe, the stimulation of photosynthesis and plant growth by “CO2 fertilization” mitigated warming, through a negative evapotranspiration feedback associated with increased vegetation cover and leaf area index. In southern Europe, increased summer dryness restricted plant growth and survival, causing a positive warming feedback through reduced evapotranspiration. Our results suggest that vegetation‐climate feedbacks over the European study area will be rather modest compared to the radiative forcing of increased global CO2 concentrations but may modify warming projections locally, regionally, and seasonally, compared with results from traditional “off‐line” regional climate models lacking a representation of the relevant feedback mechanisms.
Accumulation and local proliferation of antigen‐specific CD4+ T cells in antigen‐bearing tissue
Authors: Doebis Cornelia , Menning Astrid , Neumann Katrin , Ghani Saeed , Schlawe Kerstin , Lauer Uta , Hamann Alf , Huehn Jochen , Syrbe Uta
Published: November 2010

Although activation and subsequent expansion of naive CD4+ T cells within lymph nodes is well characterized, the fate of T effector cells activated within peripheral tissues during secondary reactions is poorly defined. Therefore, we studied the recruitment, proliferation and egress of antigen‐specific Th1 effector cells in comparison with nonspecific Th1 cells throughout a delayed‐type hypersensitivity reaction (DTH). Although we observed a high turnover of Th1 effector cells with unspecific high‐rate recruitment and CCR7‐dependent egress from the inflamed tissue in the early, acute DTH phase, a strong, selective accumulation of antigen‐specific T cells occurred during the chronic, late DTH phase. This was mainly based on local proliferation of CD4+ effector cells within the DTH tissue and concomitant retention. Considering the strong CCR7‐dependent Th cell egress found in this model, the reduced CCR7 expression on antigen‐specific T cells isolated from late‐phase DTH tissue most likely contributes to the retention of these cells within the tissue. Thus, peripheral tissues can support not only the proliferation of CD8+ T cells, as recently shown, but also that of CD4+ T effector cells, forming a pool of tissue‐resident T cells.
Modulation of the magnetism in ion implanted MnxGe1−x thin films by rapid thermal anneal
Authors: Yin Wenjing , He Li , Dolph Melissa Commisso , Lu Jiwei , Hull Robert , Wolf Stuart A.
Published: November 2010

We introduced 1.1 at. % of Mn ions into Ge thin films in order to explore the ferromagnetism in Mn implanted Ge. Rapid thermal anneal (RTA) was applied after the implantation to recrystallize the Ge and enhance the incorporation of Mn ions into the Ge lattice. A maximum saturation moment of 0.7 μB/Mn at 5 K was reached when the sample was annealed at 300 °C for 1 min, and the moment decreased with higher annealing temperatures. Two transitions temperatures Tc and Tcl were observed corresponding to the global ferromagnetism in Mn:Ge bulk and short range magnetic ordering in Mn-rich clusters. Both critical temperatures increased with RTA temperatures and Tcl even persisted close to room temperature for the 400 °C, 1 min anneal. No secondary phases were observed.
Effect of indium surfactant on stress relaxation by V-defect formation in GaN epilayers grown by metalorganic chemical vapor deposition
Authors: Won Dongjin , Weng Xiaojun , Redwing Joan M.
Published: November 2010

The effect of indium surfactant on the stress in GaN films grown on SiC at 950 °C by metalorganic chemical vapor deposition was investigated using a combination of in situ wafer curvature measurements and ex situ high resolution x-ray diffraction (HRXRD). As the molar flow rate of trimethylindium was varied from 0 to 4.5 μmol/min during growth, the real-time stress measurements showed that the mean compressive stress of the GaN films decreased from −0.60 to −0.30 GPa. The lattice constants of the GaN epilayers determined by HRXRD confirmed the stress relaxation promoted by the presence of indium while the rocking curve measurements showed that the threading dislocation (TD) density of GaN films remains nearly unchanged. Atomic force microscopy measurements showed that the indium improved step-flow growth, but simultaneously it drove V-defect formation on the GaN surface, which plays a critical role in stress relaxation of GaN films. Cross-sectional transmission electron microscopy revealed the minor contribution of plastic dislocation motion to stress relaxation by localized TD bending toward V-defects. A nucleation and growth model for the V-defect formation was developed to explain that V-defects are energetically favorable to form at TDs under indium-rich conditions. This model shows that the energy barrier for V-defect formation is significantly reduced when indium is present, which leads to the relaxation of misfit strain energy by increasing the size and density of V-defects. Initiation of V-defects and the role of TDs in V-defect formation are discussed based on the presented model.
Efficient algorithm for asymptotics-based configuration-interaction methods and electronic structure of transition metal atoms
Authors: Mendl Christian B. , Friesecke Gero
Published: November 2010

Asymptotics-based configuration-interaction (CI) methods [G. Friesecke and B. D. Goddard, Multiscale Model. Simul. 7, 1876 (2009)] are a class of CI methods for atoms which reproduce, at fixed finite subspace dimension, the exact Schrödinger eigenstates in the limit of fixed electron number and large nuclear charge. Here we develop, implement, and apply to 3d transition metal atoms an efficient and accurate algorithm for asymptotics-based CI. Efficiency gains come from exact (symbolic) decomposition of the CI space into irreducible symmetry subspaces at essentially linear computational cost in the number of radial subshells with fixed angular momentum, use of reduced density matrices in order to avoid having to store wave functions, and use of Slater-type orbitals (STOs). The required Coulomb integrals for STOs are evaluated in closed form, with the help of Hankel matrices, Fourier analysis, and residue calculus. Applications to 3d transition metal atoms are in good agreement with experimental data. In particular, we reproduce the anomalous magnetic moment and orbital filling of chromium in the otherwise regular series Ca, Sc, Ti, V, Cr.
Time-resolved measurements of plasma-induced momentum in air and nitrogen under dielectric barrier discharge actuation
Authors: Leonov Sergey , Opaits Dmitry , Miles Richard , Soloviev Victor
Published: November 2010

There has been much recent interest in boundary layer (BL) actuation by offset surface dielectric barrier discharges (SDBD). These discharges either act directly on the gas momentum through the mechanism of charge separation or they increase the flow stability through the creation of disturbances to the BL at a particular frequency. The objective of the work reported here is to clarify the physical mechanism of plasma-flow interaction. Two problems are considered in detail: the exact spatial/temporal distribution of the plasma-related force, and the specific role of negative ions in the net force budget. The experiments were made with an offset electrode configuration of SDBD at voltage amplitude U≤12 kV and frequency f=0.02–2 kHz. The main data were obtained by time-resolved Pitot tube pressure measurements in air and nitrogen at atmospheric pressure. Three main features of SDBD behavior were considered. First, the strong inhomogeneity in the spatial distribution of the plasma-induced flow were detected. Second, the principal role of negative ions in plasma-induced flow generation was established. Third, the two types of gas disturbances were observed: the thermal effect and momentum transfer effect (ion wind). To explain the aforementioned features of SDBD behavior in air and nitrogen the results of numerical simulation have been used.
Dipole moment surface of the van der Waals complex CH4–N2
Authors: Zvereva-Loëte Natalia , Kalugina Yulia N. , Boudon Vincent , Buldakov Mikhail A. , Cherepanov Victor N.
Published: November 2010

The interaction-induced dipole moment surface of the van der Waals CH4–N2 complex has been calculated for a broad range of intermolecular separations R and configurations in the approximation of the rigid interacting molecules at the MP2 and CCSD(T) levels of theory using the correlation-consistent aug-cc-pVTZ basis set with the basis set superposition error correction. The simple model to account for the exchange effects in the range of small overlap of the electron shells of interacting molecules and the induction and dispersion interactions for large R has been suggested. This model allows describing the dipole moment of van der Waals complexes in analytical form both for large R, where induction and dispersion have the key role, and for smaller R including whole ranges of their potential wells, where the exchange effects are important. The proposed model was tested on a number of configurations of the CH4–N2 complex and was applied for the analytical description of the dipole moment surface for the family of the most stable configurations of the CH4–N2 complex.
A novel laser wavelength meter based on the measurement of synthetic wavelength
Authors: Yan Liping , Chen Benyong , Yang Wanfu , Wei Ruofei , Zhao Siwei
Published: November 2010

The accuracy of the current wavelength meter using optical interferometry is limited by the numbers of fringe counted. To solve this problem, a novel laser wavelength meter based on the measurement of synthetic wavelength is proposed. The unknown wavelength is obtained by measuring the value of synthetic wavelength produced by the unknown and reference wavelengths, and half of this value corresponds to 2π variation of the phase difference between the interference signals of the unknown and reference wavelengths. The optical configuration of the wavelength meter is designed and the measurement principle is analyzed theoretically. To verify its feasibility, three helium-neon lasers’ wavelengths were determined experimentally, and a relative uncertainty on the unknown wavelength of the order of 10−8 was realized. Accuracy analysis shows that this wavelength meter has the advantage of high accuracy when the unknown wavelength is around the standard laser wavelength recommended by CIPM.
Investigation of electrical conductivity and equations of state of non-ideal plasma through underwater electrical wire explosion
Authors: Sheftman D. , Krasik Ya. E.
Published: November 2010

The results of experiments and magnetohydrodynamic simulations of nanosecond time scale underwater electrical explosions of Al, Cu, and W wires are presented. Experiments were performed using a nanosecond pulsed generator with a ∼30 kA amplitude and ∼60 ns rise time current pulse. The electrical conductivity of the tested materials in the density and temperature ranges of 0.1–20 g/cm3 and 0.03–8 eV, respectively, is presented. It is shown that for the physical conditions obtained in these experiments, the equation of state data used in the SESAME tables must be modified in order to reproduce the experimental results. Also, it was shown that the electrical conductivity of the metals does not consistently fit over the entire range of experimental conditions with either of the transport models presented.
Effect of Zn substitution on magnetic properties of nanocrystalline cobalt ferrite
Authors: Jadhav Santosh S. , Shirsath Sagar E. , Patange Sunil M. , Jadhav K. M.
Published: November 2010

The Zn substituted cobalt ferrite nanoparticles having the generic formula Co1−xZnxFe2O4 (x=0.0–0.7) were prepared by wet chemical coprecipitation technique using analytical reagent (AR) grade sulphates. The prepared samples were heated at 150 °C to remove water molecules and then annealed at 725 °C for 16 h. Investigation of the structural properties were carried out using x-ray diffraction, transmission electron microscopy (TEM), and scanning electron microscopy techniques. The nanocrystalline nature of the samples is confirmed by TEM data. Substitution of the nonmagnetic Zn2+ ions considerably changes the magnetic properties. Néel’s model fails to explain the observed magnetic behavior above x=0.2. For x≥0.2 the Yafet–Kittel model can be fitted. AC susceptibility measurements confirm the decrease in Curie temperature.
Monte Carlo simulation of carrier dynamics in terahertz quantum cascade lasers
Authors: Han Y. J. , Cao J. C.
Published: November 2010

We employ a Monte Carlo method to investigate the carrier dynamics in the terahertz quantum cascade lasers with vertical and diagonal radiative transition designs. Electron-electron and electron-phonon scattering are included in the calculations and their effects on the temperature dependence of electron transport are evaluated. The simulation shows that the degradation of temperature performance is mainly due to the rapid electron relaxation from upper to lower laser levels, in which the electron-phonon interaction is the dominant scattering mechanism. The parasitic coupling between laser levels is weakened in the diagonal design, resulting in better device performance such as lower current density, higher operating temperature, and less hot electron effects. The calculations are in good agreement with experimental results.
Mechanically tunable conjugated polymer distributed feedback lasers
Authors: Wenger Bernard , Tétreault Nicolas , Welland Mark E. , Friend Richard H.
Published: November 2010

Herein we report a low-threshold organic laser device based on semiconducting poly(9,9′-dioctylfluoren-2,7-diyl-alt-benzothiadiazole) (F8BT) encapsulated in a mechanically stretchable polydimethylsiloxane (PDMS) matrix. We take advantage of the natural flexibility of PDMS to alter the periodicity of the distributed feedback grating which in turn tunes the gain wavelength at which the resonant feedback is obtained. This way, we demonstrate that low-threshold lasing [6.1 μJ cm−2 (5.3 nJ)] is maintained over a large stretching range of 0%–7% which translates into a tuning range of about 20 nm.
Color-tunable multilayer organic light emitting diode composed of DNA complex and tris(8-hydroxyquinolinato)aluminum
Authors: Nakamura Kazuki , Ishikawa Takayuki , Nishioka Daisuke , Ushikubo Takahiro , Kobayashi Norihisa
Published: November 2010

In this study, the voltage-controlled color tunability of an organic light emitting diode composed of a DNA/Polyaniline/Ru(bpy)32+ complex (as the hole transport layer) and tris(8-hydroxyquinolinato)aluminum (as the electron transport layer) was demonstrated. At applied voltage of 5 V, green emission was observed from Alq3. As the voltage was increased, the emission color changed from green to yellow (14 V) to orange (16 V) and finally to red (18 V), with strong contribution of red emission from Ru(bpy)32+. This color tunability of the emission was principally a result of the shift in the carrier recombination region with an increase in applied voltage.
Propagation of acoustic waves and waveguiding in a two-dimensional locally resonant phononic crystal plate
Authors: Oudich Mourad , Assouar M. Badreddine , Hou Zhilin
Published: November 2010

We demonstrate the waveguiding of Lamb waves in a locally resonant phononic crystal (LRPC) and we present an analysis of the guiding of elastic waves in straight and bent waveguides. The finite element method combined with the supercell technique was used to analyze the band gap and the dispersion relation of LRPC waveguides. Unlike the traditional phononic crystals, we show the possibility of guiding only one confined mode inside a LRPC waveguide. We discuss the confinement and the transmission of the guided mode as a function of the width of the waveguide based on both the band structure and the displacement field.
High performance long wavelength infrared mega-pixel focal plane array based on type-II superlattices
Authors: Manurkar Paritosh , Ramezani-Darvish Shaban , Nguyen Binh-Minh , Razeghi Manijeh , Hubbs John
Published: November 2010

A large format 1k×1k focal plane array (FPA) is realized using type-II superlattice photodiodes for long wavelength infrared detection. Material growth on a 3 in. GaSb substrate exhibits a 50% cutoff wavelength of 11 μm across the entire wafer. The FPA shows excellent imaging. Noise equivalent temperature differences of 23.6 mK at 81 K and 22.5 mK at 68 K are achieved with an integration time of 0.13 ms, a 300 K background and f/4 optics. We report a dark current density of 3.3×10−4 A cm−2 and differential resistance-area product at zero bias R0A of 166 Ω cm2 at 81 K, and 5.1×10−5 A cm−2 and 1286 Ω cm2, respectively, at 68 K. The quantum efficiency obtained is 78%.
Light-induced instability of an InGaZnO thin film transistor with and without SiOx passivation layer formed by plasma-enhanced-chemical-vapor-deposition
Authors: Chen Te-Chih , Chang Ting-Chang , Hsieh Tien-Yu , Tsai Chih-Tsung , Chen Shih-Ching , Lin Chia-Sheng , Hung Ming-Chin , Tu Chun-Hao , Chang Jiun-Jye , Chen Po-Lun
Published: November 2010

This paper investigates the illuminated behaviors of InGaZnO thin film transistors with and without a SiOx passivation. For the passivated device, more interface states were generated during SiOx passivation layer deposition by plasma-enhanced-chemical-vapor-deposition. The enhanced trap-assisted photoexcited hole generation induces source side barrier lowering and causes an apparent subthreshold stretch-out phenomenon. However, for the unpassivated device, the fact that the threshold voltage shift in ambient oxygen is lower than in vacuum under light illumination suggests oxygen desorption and readsorption occurs simultaneously, which is consistent with the accelerated recovery rate in oxygen ambiance.
AlGaN solar-blind avalanche photodiodes with high multiplication gain
Authors: Sun Lu , Chen Jilin , Li Jianfei , Jiang Hao
Published: November 2010

We report the fabrication and characterization of the solar-blind AlGaN avalanche photodiodes grown by metal-organic chemical vapor deposition on c-plane sapphire substrate. The fabricated devices with 100 μm diameter active area exhibit a peak responsivity of 79.8 mA/W at 270 nm and zero bias, corresponding to an external quantum efficiency of 37%. Multiplication gains as high as more than 2500 were obtained in these devices.
Salmonella
pathogenicity island 2 expression negatively controlled by EIIA
Ntr
–SsrB interaction is required for
Salmonella
virulence
Authors: Choi Jeongjoon , Shin Dongwoo , Yoon Hyunjin , Kim Jiae , Lee Chang-Ro , Kim Minjeong , Seok Yeong-Jae , Ryu Sangryeol
Published: November 2010

SsrA/SsrB is a primary two-component system that mediates the survival and replication of
Salmonella
within host cells. When activated, the SsrB response regulator directly promotes the transcription of multiple genes within
Salmonella
pathogenicity island 2 (SPI-2). As expression of the SsrB protein is promoted by several transcription factors, including SsrB itself, the expression of SPI-2 genes can increase to undesirable levels under activating conditions. Here, we report that
Salmonella
can avoid the hyperactivation of SPI-2 genes by using
ptsN
-encoded EIIA
Ntr
, a component of the nitrogen-metabolic phosphotransferase system. Under SPI-2–inducing conditions, the levels of SsrB-regulated gene transcription increased abnormally in a
ptsN
deletion mutant, whereas they decreased in a strain overexpressing EIIA
Ntr
. We found that EIIA
Ntr
controls SPI-2 genes by acting on the SsrB protein at the posttranscriptional level. EIIA
Ntr
interacted directly with SsrB, which prevented the SsrB protein from binding to its target promoter. Finally, the
Salmonella
strain, either lacking the
ptsN
gene or overexpressing EIIA
Ntr
, was unable to replicate within macrophages, and the
ptsN
deletion mutant was attenuated for virulence in mice. These results indicated that normal SPI-2 gene expression maintained by an EIIA
Ntr
–SsrB interaction is another determinant of
Salmonella
virulence.
Sex difference in cell proliferation in developing rat amygdala mediated by endocannabinoids has implications for social behavior
Authors: Krebs-Kraft Desiree L. , Hill Matthew N. , Hillard Cecilia J. , McCarthy Margaret M.
Published: November 2010

The amygdala is a sexually dimorphic brain region critical for the regulation of social, cognitive, and emotional behaviors, but both the nature and the source of sex differences in the amygdala are largely unknown. We have identified a unique sex difference in the developing rat medial amygdala (MeA) that is regulated by cannabinoids. Newborn females had higher rates of cell proliferation than males. Treatment of neonates with the cannabinoid receptor agonist, WIN 55,212–2 (WIN), reduced cell proliferation in females to that of males and a wide range of WIN doses had no effect on cell proliferation in males. The effect of WIN on cell proliferation in the MeA was prevented by coinfusions of a CB2 but not CB1 receptor antagonist. Females had higher amygdala content of the endocannabinoid degradation enzymes, fatty acid amid hydrolase, and monoacylglycerol lipase than males, and lower amounts of the endocannabinoids 2-arachidonoylglycerol and
N
-arachidonylethanolamide (anandamide). Inhibition of the degradation of 2-arachidonoylglycerol in females occluded the sex difference in cell proliferation. Analyses of cell fate revealed that females had significantly more newly generated glial cells but not more newly generated neurons than males, and treatment with WIN significantly decreased glial cell genesis in females but not males. Finally, early exposure to cannabinoids masculinized juvenile play behavior in females but did not alter this behavior in males. Collectively, our findings suggest that sex differences in endocannabinoids mediate a sex difference in glial cell genesis in the developing MeA that impacts sex-specific behaviors in adolescence.
Hydrogenation of N over Fe{111}
Authors: Iyngaran Poobalasuntharam , Madden David C. , Jenkins Stephen J. , King David A.
Published: November 2010

Over the past five decades, ultra high vacuum (uhv) techniques applied to well-defined single-crystal samples (the “surface science paradigm”) have transformed our understanding of fundamental surface chemistry. To translate this success to the world of realistic heterogeneous catalysis, however, requires one seriously to address the fact that real heterogeneous catalysts usually operate under near-ambient or higher pressures. Nevertheless, the surface science paradigm can undoubtedly provide crucial insights into catalytic processes, so long as care is exercised in the design of experiments. Forging a secure link between two radically different pressure regimes is the major challenge, which we illustrate here with reference to the vitally important ammonia synthesis reaction, achieved industrially only under extremely high pressure.
Electronic decoupling of a cyclophane from a metal surface
Authors: Matino Francesca , Schull Guillaume , Köhler Felix , Gabutti Sandro , Mayor Marcel , Berndt Richard
Published: November 2010

Electronic self-decoupling of an organic chromophore from a metal substrate is achieved using a naphtalenediimide cyclophane to spatially separate one chromophore unit of the cyclophane from the substrate. Observations of vibronic excitations in scanning tunneling spectra demonstrate the success of this approach. These excitations contribute a significant part of the tunneling current and give rise to clear structure in scanning tunneling microscope images. We suggest that this approach may be extended to implement molecular functions at metal surfaces.