bluuebunny/crossref_metadata_2025 huggingface dataset:
Synergistic induction of apoptosis by the Bcl‐2 inhibitor ABT‐737 and imatinib mesylate in gastrointestinal stromal tumor cells
Authors: Reynoso David , Nolden Laura K. , Yang Dan , Dumont Sarah N. , Conley Anthony P. , Dumont Amaury G.P. , Zhou Kim , Duensing Anette , Trent Jonathan C.
Published: October 2010

Background: Although imatinib mesylate has revolutionized the management of patients with gastrointestinal stromal tumor (GIST), resistance and progression almost inevitably develop with long‐term monotherapy. To enhance imatinib‐induced cytotoxicity and overcome imatinib‐resistance in GIST cells, we examined the antitumor effects of the pro‐apoptotic Bcl‐2/Bcl‐xL inhibitor ABT‐737, alone and in combination with imatinib.

Methods: We treated imatinib‐sensitive, GIST‐T1 and GIST882, and imatinib‐resistant cells with ABT‐737 alone and with imatinib. We determined the anti‐proliferative and apoptotic effects by cell viability assay, flow cytometric apoptosis and cell cycle analysis, immunoblotting, and nuclear morphology. Synergism was determined by isobologram analysis.

Results: The IC50 of single‐agent ABT‐737 at 72 h was 10 μM in imatinib‐sensitive GIST‐T1 and GIST882 cells, and 1 μM in imatinib‐resistant GIST48IM cells. ABT‐737 and imatinib combined synergistically in a time‐ and dose‐dependent manner to inhibit the proliferation and induce apoptosis of all GIST cells, as evidenced by cell viability and apoptosis assays, caspase activation, PARP cleavage, and morphologic changes. Isobologram analyses revealed strongly synergistic drug interactions, with combination indices <0.5 for most ABT‐737/imatinib combinations. Thus, clinically relevant in vitro concentrations of ABT‐737 have single‐agent antitumor activity and are synergistic in combination with imatinib.

Conclusion: We provide the first preclinical evidence that Bcl‐2/Bcl‐xL inhibition with ABT‐737 synergistically enhances imatinib‐induced cytotoxicity via apoptosis, and that direct engagement of apoptotic cell death may be an effective approach to circumvent imatinib‐resistance in GIST.
Cochlear Implantation in Brown–Vialetto–Van-Laere syndrome
Authors: Sinnathuray A R , Watson D R , Fruhstorfer B , Olarte J R , Toner J G
Published: October 2010

Objective:

To report outcomes for the first known cochlear implantation procedures in two patients with Brown–Vialetto–Van-Laere syndrome.

Patients:

Two adult patients (a brother and sister) with post-lingual sensorineural deafness associated with Brown–Vialetto–Van-Laere syndrome. The female patient presented with a milder form of the syndrome.

Intervention:

Cochlear implantation.

Main outcome measure:

Post-implantation speech discrimination scores.

Results:

Auditory evoked potential testing suggested pathological changes in both patients' cochleae, auditory nerves, brainstem and (probably) central auditory pathways. In the male patient, despite implantation of the better ear, the Bamford–Kowal–Bench sentence score was zero at 21 months post-implantation. In the female patient, Bamford–Kowal–Bench sentence scores at six months post-implantation were 25 per cent in quiet and 3 per cent in noise.

Conclusion:

These poor clinical outcomes appear to be related to retrocochlear and probable central auditory pathway degeneration.
Serum matrix metalloproteinases and tympanosclerosis
Authors: Aslan H , Başoğlu M Sinan , Şentürk B , Özbay C , Katilmiş H , Öztürkcan S
Published: October 2010

Aim:

To investigate levels of matrix metalloproteinases 2 and 9, and of their tissue inhibitor (i.e. tissue inhibitor matrix metalloproteinase 1), in the serum of patients with tympanosclerosis.

Materials and method:

We included 40 patients (age range 13–63 years) who had undergone surgery in the ENT department of İzmir Atatürk Training and Research Hospital between 2002 and 2007. Twenty had uncomplicated chronic otitis media and 20 had tympanosclerosis. We also included as the control group 20 individuals with no history of previous otic complaints or systemic or infectious disease. Serum levels of serum matrix metalloproteinases 2 and 9 and of tissue inhibitor matrix metalloproteinase 1 were measured in all subjects and compared.

Result:

Significantly higher levels of serum matrix metalloproteinases 2 and 9 were found in the tympanosclerosis group, compared with the chronic otitis media and control groups. There was no statistically significant difference in tissue inhibitor matrix metalloproteinase 1 level between the three groups.

Conclusion:

Tympanosclerosis surgery has poor success rates, since the pathological process is still active. We suggest that high levels of matrix metalloproteinases may play a role in the continuation of the disease process.
Metabolic syndrome in the elderly living in marginal peri-urban communities in Quito, Ecuador
Authors: Sempértegui Fernando , Estrella Bertha , Tucker Katherine L , Hamer Davidson H , Narvaez Ximena , Sempértegui Mercy , Griffiths Jeffrey K , Noel Sabrina E , Dallal Gerard E , Selhub Jacob , Meydani Simin N
Published: October 2010

Objective

The proportion of the Latin American population aged >60 years is expected to double during the next few decades. Metabolic syndrome (MetS) is associated with high morbidity and mortality worldwide. However, little is known about MetS in Latin America in general, and in Ecuador in particular. The present study aimed to examine the prevalence of MetS and its association with blood micronutrient, homocysteine (Hcy) and C-reactive protein (CRP) concentrations in the elderly living in a low-income urban area.

Design

We performed a cross-sectional study. MetS, using the International Diabetes Federation definition, dietary intake and plasma micronutrient, CRP and Hcy concentrations were assessed.

Subjects

A total of 352 elderly (≥65 years) Ecuadorians.

Setting

Quito, Ecuador.

Results

MetS was prevalent (40 %) – considerably more so among women (81 %) than men (19 %;χ2= 32·6,P< 0·0001). Further, 53 % of those without MetS exhibited two or more of its components. Micronutrient deficiencies were prevalent, including those of vitamin C, zinc, vitamin B12and folate. Vitamin C and E concentrations were inversely (OR = 0·78, 95 % CI 0·71, 0·86; OR = 0·16, 95 % CI 0·03, 0·81, respectively) and CRP (OR = 1·79, 95 % CI 1·04, 3·06) was positively associated with MetS.

Conclusions

The coexistence of MetS with micronutrient deficiencies suggests that elderly Ecuadorians suffer from the double burden of diseases that are increasingly being observed in less developed countries. More research is needed to determine the causal factors, but results presented suggest that these older adults would benefit from interventions to reduce the risk factors for MetS, in particular higher consumption of micronutrient-rich foods.
On the rise and Decline of the Monarchical Principle: Constitutional Vicissitudes in Spain and Germany
Authors: Prakke Lucas
Published: October 2010

Nation-state formation – Holy Roman Empire – Dissolution and realignment – Spain, fragmented – Reconquista – Charles V – Wars of succession – Centralisation under house of Bourbon – Napoleon – Spanish war of independence – History of the Cortes – Constitution of Cádiz – Weakness of Spanish Constitutionalism – German Confederation – Monarchical principle in Vienna Final Act – Old and new ideas of sovereignty – Metternich and fear of revolution – March revolution – Bismarckian empire as constitutional monarchy – Degeneration of the Reich – Exit the Kings – Enter Juan Carlos
An Eventful Life Remembered: Recent Considerations of the Contributions and Legacy of Francis O'Neill
Authors: SOMMERS SMITH SALLY K.
Published: October 2010

Francis O'Neill, one of the towering figures of Irish traditional music, was among the first to collect and publish Irish dance music. His compilations form the most complete glimpse into Irish musical practice at the turn of the twentieth century and are still regarded as the definitive source for traditional tunes. Three recent publications on O'Neill and his times throw light on his life, his passion for the music, and his legacy among today's traditional music community.
Wheels of the World: How Recordings of Irish Traditional Music Bridged the Gap between Homeland and Diaspora
Authors: SPENCER SCOTT
Published: October 2010

At the dawn of the twentieth century and the height of the Recording Age, Irish American musicians began to record Irish traditional music on both commercial and subcommercial recordings. Circulated within the diaspora during a changing sense of Irish identity and sent home to a nationalist revival, these recordings had a profound impact on both traditional performance practices and modes of transmission. Quickly accepted by many at the heart of the tradition, these recordings were used by practitioners to bridge vast geographic distances and solidify vital lines of communication, allowing the diaspora to engage actively with the larger tradition.
60 GHz current gain cut-off frequency graphene nanoribbon FET
Authors: Meng Nan , Ferrer Francsico-Javier , Vignaud Dominique , Dambrine Gilles , Happy Henri
Published: October 2010

We report investigations on the fabrication and characterization of graphene nanoribbon (GNR) field-effect transistors. Graphene layers are obtained from the thermal decomposition of a Si-face 4H-SiC substrate. To achieve high dynamic performance, a structure with an array of GNR connected in parallel was fabricated by e-beam lithography. The best intrinsic current gain cut-off frequency of 60 GHz and maximum oscillation frequency of 28 GHz were achieved. This study demonstrates the exciting potential of GNR in high-frequency electronics.
ENSO influences on Southern Hemisphere column ozone during the winter to spring transition
Authors: Hitchman M. H. , Rogal M. J.
Published: October 2010

This study investigates how the El Nino Southern Oscillation (ENSO) modulates the distribution of column ozone during the Southern Hemisphere (SH) winter to spring transition, when a zonal asymmetry in column ozone develops near 55°S, with a maximum south of Australia. ENSO differences in column ozone and planetary wave structure are explored for the average of seven El Nino (EN) versus six La Nina (LN) events during 1982–2004. A westward shift in convection during LN corresponds to a 30–50° westward shift of SH planetary wave and column ozone patterns. The extratropical lower stratospheric temperature anomalies are inversely correlated with tropical anomalies in similar longitude bands and are highly correlated with local column ozone anomalies. The tropical signal is communicated to higher latitudes by modulating subtropical anticyclones, with distinctive responses for EN and LN years for each month. During August and EN a subtropical anticyclone extends from South America to South Africa, and the wave one asymmetry of the Antarctic vortex is more pronounced and shifted eastward, along with column ozone. In September and EN a strong anticyclone exists over South Africa, with a corresponding cold, ozone‐poor anomaly in the stratosphere, diminishing the western edge of the ozone maximum. In October and LN a strong anticyclone exists over Australia, with an amplified trough on its poleward flank. This trough is overlain by an ozone‐rich warm anomaly, which expands the western edge of the ozone maximum, and the polar vortex asymmetry is amplified and rotated westward.
Combined GRACE and InSAR estimate of West Antarctic ice mass loss
Authors: Sasgen I. , Martinec Z. , Bamber J.
Published: October 2010

We estimate the mass balance of eight drainage basins in West Antarctica from the Gravity Recovery and Climate Experiment (GRACE) data (GFZ RL04, GSM Level 2) using a constrained inverse‐gravimetric approach. We consider InSAR observations of ice surface velocity as an indication of mass change, assuming that large mass loss occurs in areas of fast glacier flow. From these mass distribution functions we construct forward models of the geoid height change and their spatial correlations for each drainage basin. Then the difference between the GRACE data and the forward model is minimized by adjusting the total amount of mass change within each drainage basin. To overcome the ambiguity inherent in this inverse problem, we constrain its solution by including a priori estimates based on the InSAR mass‐budget method. However, unconstrained (GRACE only) mass‐change estimates can be recovered for three to four combined drainage basins. Differences between GRACE and InSAR values exist mainly for the Pine Island Glacier and Getz Ice Shelf region, resulting in a lower unconstrained GRACE total of −91.0 ± 3.5 Gt/yr (for the years 2002–2008) compared to the InSAR estimate of −116.6 ± 19.0 Gt/yr (outflow measurement for the years 1992, 1996, and 2006). There is evidence that this difference arises from anomalously large accumulation within the GRACE time interval (August 2002 to August 2008) in the Amundsen Sea sector and possibly from an overestimation of ice thickness for parts of the Bellinghausen Sea sector underlying the InSAR mass‐budget values.
The mARM3D spatially distributed soil evolution model: Three‐dimensional model framework and analysis of hillslope and landform responses
Authors: Cohen Sagy , Willgoose Garry , Hancock Greg
Published: October 2010

We present a three‐dimensional landscape‐pedogenesis model, mARM3D (matrices ARMOUR 3D), which simulates soil evolution as a function of erosion and pedogenic processes. The model simulates the discretized soil profile for points on a spatial grid. The approach, using transition matrices, is computationally efficient and allows the simulation of large‐scale spatial coupling and long‐term soil evolution. We study the effect of the depth‐dependent soil‐weathering rate (i.e., the rate of soil particle breakdown) and bedrock‐lowering rate (i.e., the rate of conversion of bedrock to soil). The difference in depth‐dependent weathering functions has a significant effect on the in‐profile soil properties through depth, specifically particle size grading. However, the depth dependency has a relatively minor effect on the surface properties of the soil profile, with all weathering functions generating very similar surface properties. The surface properties were a function of the cumulative amount of weathering (i.e., the integral of the weathering function over exhumation) with finer surface grading for higher weathering rates. Soil thickness could be estimated without explicitly modeling soil thickness. Thickness was negatively correlated with surface median grain size. As thickness decreases, the surface grading coarsens. This was driven by surface erosion, where as surface grading coarsens, erosion decreases and the soil deepens. Weathering and erosion interact to spatially organize the surface soil grading with a log‐log relationship between surface grading, contributing area, and local slope. This relationship was independent of the weathering function. This relationship might be useful for the spatial description of soil properties in digital soil mapping.
Simultaneous observations of reconnection pulses at Cluster and their effects on the cusp aurora observed at the Chinese Yellow River Station
Authors: Zhang Q.‐H. , Dunlop M. W. , Lockwood M. , Liu R.‐Y. , Hu H.‐Q. , Yang H.‐G. , Hu Z.‐J. , Bogdanova Y. V. , Shen C. , Zhang B.‐C. , Han D.‐S. , Liu S.‐L. , McCrea I. W. , Lester M.
Published: October 2010

While the Cluster spacecraft were located near the high‐latitude magnetopause, between 1010 and 1040 UT on 16 January 2004, three typical flux transfer event (FTE) signatures were observed. During this interval, simultaneous and conjugated all‐sky camera measurements, recorded at Yellow River Station, Svalbard, are available at 630.0 and 557.7 nm that show poleward‐moving auroral forms (PMAFs), consistent with magnetic reconnection at the dayside magnetopause. Simultaneous FTEs seen at the magnetopause mainly move northward, but having duskward (eastward) and tailward velocity components, roughly consistent with the observed direction of motion of the PMAFs in all‐sky images. Between the PMAFs meridional keograms, extracted from the all‐sky images, show intervals of lower intensity aurora which migrate equatorward just before the PMAFs intensify. This is strong evidence for an equatorward eroding and poleward moving open‐closed boundary associated with a variable magnetopause reconnection rate under variable IMF conditions. From the durations of the PMAFs, we infer that the evolution time of FTEs is 5–11 minutes from its origin on the magnetopause to its addition to the polar cap.
Extraordinary field‐aligned current signatures in Saturn's high‐latitude magnetosphere: Analysis of Cassini data during Revolution 89
Authors: Bunce E. J. , Cowley S. W. H. , Talboys D. L. , Dougherty M. K. , Lamy L. , Kurth W. S. , Schippers P. , Cecconi B. , Zarka P. , Arridge C. S. , Coates A. J.
Published: October 2010

During the periapsis pass of Revolution 89, specifically on day 291 of 2008, the Cassini spacecraft observed unusual field‐aligned current signatures in Saturn's high‐latitude southern hemisphere in the midnight and dawn sector. The region of open field lines was found to be contracted close to the pole, and surrounded by an unusual region containing hot keV electrons and ‘leading’ field signatures indicative of super‐corotating flow. Usual ‘lagging’ fields indicative of sub‐corotating flow were also present at lower latitudes, though of unusual strength. Unique within the ∼40 similar nightside auroral region Cassini passes during 2008, the overall field‐aligned current system thus consisted of a central region of downward current flanked by two regions of upward current. This distinctive signature coincided with the first in situ encounter of Cassini with a source region of Saturn kilometric radiation, located within the unusual poleward region of upward current adjacent to the open‐closed field line boundary. We propose that these unusual conditions relate to a major open flux closure event in Saturn's tail, possibly triggered by solar wind compression of the magnetosphere.
Foregut microbiome in development of esophageal adenocarcinoma
Authors: Nossa Carlos , Francois Fritz , Torralba Manolito , Brown Stuart , Traube Morris , Yooseph Shibu , Chen Yu , Singh Navjeet , Rogers Yu-Hui , Liu Mengling , DeSantis Todd , Brodie Eoin , Andersen Gary , Nelson Karen , Yang Liying , Bihan Monika , Pei Zhiheng , Oberdorf William , Foster Les , Gerz Erika , Tenney Aaron , Parsons Tamasha , Brami Daniel , Thiagarajan Mathangi , Shah Pinak , Poles Michael , Singh Indresh , Bedi Sukhleen
Published: October 2010

Esophageal adenocarcinoma (EA), the type of cancer linked to heartburn due to gastroesophageal reflux diseases (GERD), has increased six fold in the past 30 years. This cannot currently be explained by the usual environmental or by host genetic factors. EA is the end result of a sequence of GERD-related diseases, preceded by reflux esophagitis (RE) and Barrett’s esophagus (BE). Preliminary studies by Pei and colleagues at NYU on elderly male veterans identified two types of microbiotas in the esophagus. Patients who carry the type II microbiota are >15 fold likely to have esophagitis and BE than those harboring the type I microbiota. In a small scale study, we also found that 3 of 3 cases of EA harbored the type II biota. The findings have opened a new approach to understanding the recent surge in the incidence of EA.Our long-term goal is to identify the cause of GERD sequence. The hypothesis to be tested is that changes in the foregut microbiome are associated with EA and its precursors, RE and BE in GERD sequence. We will conduct a case control study to demonstrate the microbiome disease association in every stage of GERD sequence, as well as analyze the trend in changes in the microbiome along disease progression toward EA, by two specific aims. Aim 1 is to conduct a comprehensive population survey of the foregut microbiome and demonstrate its association with GERD sequence. Furthermore, spatial relationship between the esophageal microbiota and upstream (mouth) and downstream (stomach) foregut microbiotas as well as temporal stability of the microbiome-disease association will also be examined. Aim 2 is to define the distal esophageal metagenome and demonstrate its association with GERD sequence. Detailed analyses will include pathway-disease and gene-disease associations. Archaea, fungi and viruses, if identified, also will be correlated with the diseases. A significant association between the foregut microbiome and GERD sequence, if demonstrated, will be the first step for eventually testing whether an abnormal microbiome is required for the development of the sequence of phenotypic changes toward EA. If EA and its precursors represent a microecological disease, treating the cause of GERD might become possible, for example, by normalizing the microbiota through use of antibiotics, probiotics, or prebiotics. Causative therapy of GERD could prevent its progression and reverse the current trend of increasing incidence of EA.
Trends in High-Temperature Polymer Electrolyte Fuel Cells
Authors: Lehnert Werner , Wannek Christoph , Zeis Roswitha
Published: October 2010

The HT-PEFC, based on polybenzimidazole type membranes doped with phosphoric acid, has a typical operating temperature of 160 °C. As a result of the high temperature level, it has a high CO tolerance, which means that it is particularly suitable for operation in combination with reformers. Compared to Nafion-based polymer electrolyte membrane fuel cells, water is not required for the ionic conductivity of the membrane; therefore the gases do not need to be humidified. Another advantage of HT-PEFC technology is that due to the high temperature difference between the stack and the ambient temperatures, cooling can be designed in a much more compact manner than is necessary in classical PEMFC systems.

However, for all these advantages, prevention measures must be in place to ensure that the acid is not discharged from the membrane. Operating conditions that could create liquid water in the cells should be avoided. Save operation below 120°C is possible only with pure hydrogen. Due to the decreasing CO tolerance with decreasing temperature operation above 120°C is necessary if the fuel contains typical CO concentrations of 1%. Operation in low temperature ranges should therefore be avoided. This has been taken into account by operating strategies and the specific areas of application. In this context the oxygen reduction reaction and operation behaviour of cells and stacks will be discussed.
Capturing a Single Cell
Authors: Rey Catherine , Wierinckx Anne , Croze Séverine , Legras-Lachuer Catherine , Lachuer Joel
Published: October 2010

A major problem encountered in genomic and proteomic studies arises from the heterogeneous nature of different tissue. Analysis of a pure cell population is essential for correlating relevant molecular signatures in diseased and disease-free cells. During the last 30 years this challenge has led to the development of different technologies able to isolate cells of interest. Laser capture microdissection (LCM) is the last available technology using the precision of a laser beam to isolate single cells from complex tissue. In this chapter we will review the different technologies available and some applications.
Looking at the DNA of a Single Cell
Authors: Polzer Bernhard , Klein Christoph A.
Published: October 2010

Small amounts of genomic DNA frequently impede genetic analyses in many fields of research, including forensic research, prenatal diagnosis or, as discussed earlier in chapter 6, oncology. To overcome these limitations amplification of genomic DNA may provide quantities of DNA needed for downstream applications. This chapter will describe methods currently available to analyse the DNA of single cells. A focus will be on whole genome amplification (WGA) of single cells and the advantages and drawbacks of available protocols will be discussed.
Analysis of Proteins at the Single Cell Level
Authors: Le Gac Séverine
Published: October 2010

Proteins bring a consequent additional level of information in comparison with nucleic acids on a cell's state as proteins are dynamically processed and chemically modified in the cell as a function of the cell life. Yet, the analysis of proteins is challenging as no amplification step is possible as is the case for nucleic acids, and another difficulty lies in the dynamic range of protein expression in a single sample (e.g. a single cell). While the same challenges are still found for microfluidic-based analysis of proteins, microsystems bring about enhanced analytical performance and novel analysis opportunities. This is illustrated here for two different strategies that can be adopted for protein analysis in a chip format. A first strategy consists of transposing the standard proteomic protocol in miniaturized analytical tools, and this provides a number of advantages and enhancement for the analysis: an overall improvement is expected when using smaller systems whose capacity matches better the size of the samples; sample manipulation is minimized when using LOC technology, and this goes together with a decrease in sample loss and contamination; enhanced analytical performance in terms of analysis time and detection sensitivity is ensured by micro- and nano-scale features; last, the use of microfabricated structures guarantees higher analysis reproducibility. In a second strategy, the analysis is actually performed at the single cell level. This strategy does not enable protein mapping anymore, but the investigation focuses on given proteins (a single protein of a small number thereof) which are specifically targeted. For that purpose, innovative microfluidic-based protocols have been developed, and we classify them in three categories of fully destructive, partially invasive and non invasive protocols. Ongoing developments in the area of nanotechnology would enable truly protein mapping at the single cell level, with the use of nanofabricated tools in a LOC platform
Studying Multilingualism and Group Differences in Adult Communication
Authors: Obler Loraine K.
Published: October 2010

The focus of this article is on the study of bilingual and multilingual adults at the Howard Goodglass Aphasia Research Center and the Language in the Aging Brain Laboratory by Drs. Obler and Albert along with former students and colleagues. Summaries of studies examining research in healthy bilingual adults, healthy monolingual older adults, and monolingual and bilingual individuals with aphasia are presented.
Potential structure around the Cassini spacecraft near the orbit of Enceladus
Authors: Olson J. , Miloch W. J. , Ratynskaia S. , Yaroshenko V.
Published: October 2010

We present the results of numerical simulations of the potential structure around an object in a streaming plasma with parameters relevant for the Cassini spacecraft passing through Saturn’s plasma disk near the orbit of Enceladus. Two- and three-dimensional particle-in-cell codes have been used allowing the potential of the simulated spacecraft body to develop self-consistently through the collection of charge by its surface. The dependence of the density and potential profiles on ambient plasma density, electron temperature, and ion drift speed is discussed. The spacecraft floating potential values, found in the simulations, are compared to those deduced from the analysis of Cassini Langmuir probe characteristics.
Design of an ignition target for the laser megajoule, mitigating parametric instabilities
Authors: Laffite S. , Loiseau P.
Published: October 2010

Laser plasma interaction (LPI) is a critical issue in ignition target design. Based on both scaling laws and two-dimensional calculations, this article describes how we can constrain a laser megajoule (LMJ) [J. Ebrardt and J. M. Chaput, J. Phys.: Conf. Ser. 112, 032005 (2008)] target design by mitigating LPI. An ignition indirect drive target has been designed for the 2/3 LMJ step. It requires 0.9 MJ and 260 TW of laser energy and power, to achieve a temperature of 300 eV in a rugby-shaped Hohlraum and give a yield of about 20 MJ. The study focuses on the analysis of linear gain for stimulated Raman and Brillouin scatterings. Enlarging the focal spot is an obvious way to reduce linear gains. We show that this reduction is nonlinear with the focal spot size. For relatively small focal spot area, linear gains are significantly reduced by enlarging the focal spot. However, there is no benefit in too large focal spots because of necessary larger laser entrance holes, which require more laser energy. Furthermore, this leads to the existence, for a given design, of a minimum value for linear gains for which we cannot go below.
Influence of a low frequency vibration on a long-wave Marangoni instability in a binary mixture with the Soret effect
Authors: Fayzrakhmanova I. S. , Shklyaev S. , Nepomnyashchy A. A.
Published: October 2010

We study the influence of a low frequency vibration on a long-wave Marangoni convection in a layer of a binary mixture with the Soret effect. A linear stability analysis is performed numerically by means of the Floquet theory; several limiting cases are treated analytically. Competition of subharmonic, synchronous, and quasiperiodic modes is considered. The vibration is found to destabilize the layer, decreasing the stability threshold. Also, a vibration-induced mode is detected, which takes place even for zero Marangoni number.
Toroidal universal drift instability: A global gyrokinetic study
Authors: Chowdhury J. , Ganesh R. , Brunner S. , Vaclavik J. , Villard L.
Published: October 2010

An electron density gradient driven instability identified as the toroidal branch of the universal drift instability is studied using a global gyrokinetic model treating both electrons and ions fully nonadiabatically and valid at all orders in the ratio of the Larmor radius to the wavelength. The physics of the magnetic drift resonance, Landau resonance and transit resonance, which are considered to be important for the toroidal universal mode, are kept for both species. A systematic parametric study is carried out for the mode. The toroidal universal drift mode is observed to sustain finite temperature gradient and can thus coexist with the temperature gradient driven modes and may contribute to the observed particle transport along with other drift modes. Especially at intermediate scales between the ion temperature gradient driven mode and electron temperature gradient driven mode, this branch of the drift instability can also be a plausible candidate for the observed particle loss. The effect of magnetic fluctuations on the mode is also investigated. In contrast to the slab mode, the toroidal branch of the universal drift mode is found to be strongly stabilized by electromagnetic effects at finite plasma β. Finally, the effect of trapped electrons on the universal mode is studied and compared with the other possible modes in the same parameter regime, namely, ion temperature gradient mode in the presence of trapped electrons and pure trapped electron modes.
Stochastic quantization of real-time thermal field theory
Authors: de Aguiar T. C. , Svaiter N. F. , Menezes G.
Published: October 2010

We use the stochastic quantization method to obtain the free scalar propagator of a finite temperature field theory formulated in the Minkowski space-time. First, we use the Markovian stochastic quantization approach to present the two-point function of the theory. Second, we assume a Langevin equation with a memory kernel and a colored noise. The convergence of the Markovian and non-Markovian stochastic processes in the asymptotic limit of the fictitious time is obtained. Our formalism can be the starting point to discuss systems at finite temperature out of equilibrium.
Translocation of α-helix chains through a nanopore
Authors: Yang Zhiyong , Li Shiben , Zhang Linxi , ur Rehman Ateeq , Liang Haojun
Published: October 2010

The translocation of α-helix chains through a nanopore is studied through Langevin dynamics simulations. The α-helix chains exhibit several different characteristics about their average translocation times and the α-helix structures when they transport through the nanopores under the driving forces. First, the relationship between average translocation times τ and the chain length N satisfies the scaling law, τ∼Nα, and the scaling exponent α depends on the driving force f for the small forces while it is close to the Flory exponent (ν) in the other force regions. For the chains with given chain lengths, it is observed that the dependence of the average translocation times can be expressed as τ∼f−1/2 for the small forces while can be described as τ∼f in the large force regions. Second, for the large driving force, the average number of α-helix structures Nh decreases first and then increases in the translocation process. The average waiting time of each bead, especially of the first bead, is also dependent on the driving forces. Furthermore, an elasticity spring model is presented to reasonably explain the change of the α-helix number during the translocation and its elasticity can be locally damaged by the large driving forces. Our results demonstrate the unique behaviors of α-helix chains transporting through the pores, which can enrich our insights into and knowledge on biopolymers transporting through membranes.
Spatially resolved probing of Preisach density in polycrystalline ferroelectric thin films
Authors: Guo S. , Ovchinnikov O. S. , Curtis M. E. , Johnson M. B. , Jesse S. , Kalinin S. V.
Published: October 2010

Applications of the ferroelectric materials for the information storage necessitate the understanding of local switching behavior on the level of individual grains and microstructural elements. In particular, implementation of multilevel neuromorphic elements requires the understanding of history-dependent polarization responses. Here, we introduce the spatially resolved approach for mapping local Preisach densities in polycrystalline ferroelectrics based on first-order reversal curve (FORC) measurements over spatially resolved grid by piezoresponse force spectroscopy using tip-electrode. The band excitation approach allowed effective use of cantilever resonances to amplify weak piezoelectric signal and also provided insight in position-, voltage-, and voltage history-dependent mechanical properties of the tip-surface contact. Several approaches for visualization and comparison of the multidimensional data sets formed by FORC families or Preisach densities at each point are introduced and compared. The relationship between switching behavior and microstructure is analyzed.
Power series expansion of the random phase approximation correlation energy: The role of the third- and higher-order contributions
Authors: Lu Deyu , Nguyen Huy-Viet , Galli Giulia
Published: October 2010

We derive a power expansion of the correlation energy of weakly bound systems within the random phase approximation (RPA), in terms of the Coulomb interaction operator, and we show that the asymptotic limit of the second- and third-order terms yields the van der Waals (vdW) dispersion energy terms derived by Zaremba–Kohn and Axilrod–Teller within perturbation theory. We then show that the use of the second-order expansion of the RPA correlation energy results in rather inaccurate binding energy curves for weakly bonded systems, and discuss the implications of our findings for the development of approximate vdW density functionals. We also assess the accuracy of different exchange energy functionals used in the derivation of vdW density functionals.
Intramolecular energy transfer dynamics in 24-mode pyrazine by partitioning technique: A time-dependent approach
Authors: Thanopulos Ioannis , Brumer Paul , Shapiro Moshe
Published: October 2010

We investigate the intramolecular energy transfer dynamics of the S2 excited electronic state of pyrazine due to radiationless transitions to energetically lower-lying singlet electronic states using a new time-dependent method. The femtosecond decay of S2 to the S1 excited state and the picosecond decay of S2 to the ground electronic state S0 are studied within an efficient methodology for computing the intramolecular dynamics in multidimensional configurational spaces. Our method is based on partitioning the full configuration space into the (small) subspace of interest Q and the rest, the subspace P. The exact equations of motion for the states in Q, under the influence of P, are derived in the time domain in form of a system of integrodifferential equations. Their numerical solution is readily obtained when the Q space consists of just a few states. Otherwise, the integrodifferential equations for the states in Q are transformed into a (larger) system of ordinary differential equations, which can be solved by a single diagonalization of a general complex matrix. The former approach is applied to study the pyrazine picosecond S2→S0 dynamics and the latter is applied to the study of the ultrafast pyrazine S2→S1 decay dynamics.
Treadmilling of actin filaments via Brownian dynamics simulations
Authors: Guo Kunkun , Shillcock Julian , Lipowsky Reinhard
Published: October 2010

Actin polymerization is coupled to the hydrolysis of adenosine triphosphate (ATP) into adenosine diphosphate (ADP) and inorganic phosphate (Pi). Therefore, each protomer within an actin filament can attain three different nucleotide states corresponding to bound ATP, ADP/Pi, and ADP. These protomer states form spatial patterns on the growing (or shrinking) filaments. Using Brownian dynamics simulations, the growth behavior of long filaments is studied, together with the associated protomer patterns, as a function of ATP-actin monomer concentration, CT, within the surrounding solution. For concentrations close to the critical concentration CT=CT,cr, the filaments undergo treadmilling, i.e., they grow at the barbed and shrink at the pointed end, which leads to directed translational motion of the whole filament. The corresponding nonequilibrium states are characterized by several global fluxes and by spatial density and flux profiles along the filaments. We focus on a certain set of transition rates as deduced from in vitro experiments and find that the associated treadmilling (or turnover) rate is about 0.08 monomers per second.
Sculpting nanoscale precipitation patterns in nanocomposite thin films via hyperthermal ion deposition
Authors: Abrasonis Gintautas , Kovács György J. , Tucker Mark D. , Heller René , Krause Matthias , Guenette Mathew C. , Munnik Frans , Lehmann Jan , Tadich Anton , Cowie Bruce C. C. , Thomsen Lars , Bilek Marcela M. M. , Möller Wolfhard
Published: October 2010

Control of the morphology of self-organized nanostructures is the key issue in bottom-up approaches. Here, morphological transitions of precipitation patterns in C:Cu nanocomposite films are studied. The films have been grown by oblique incidence ionized physical vapor deposition. We show that the ion energy and directionality are transferred into the C–Cu phase separation process resulting in nanopattern formation and tilt. Increasing metal content induces the “tilted”-“lying” transition accompanied with Cu nanoparticle prolate-spherical-oblate shape transformations. The results allow the identification of metal subplantation as the key atomistic mechanism, and demonstrate the possibility to achieve nanoscale sculpting via energetic ion deposition.
Hindered rotor models with variable kinetic functions for accurate thermodynamic and kinetic predictions
Authors: Reinisch Guillaume , Leyssale Jean-Marc , Vignoles Gérard L.
Published: October 2010

We present an extension of some popular hindered rotor (HR) models, namely, the one-dimensional HR (1DHR) and the degenerated two-dimensional HR (d2DHR) models, allowing for a simple and accurate treatment of internal rotations. This extension, based on the use of a variable kinetic function in the Hamiltonian instead of a constant reduced moment of inertia, is extremely suitable in the case of rocking/wagging motions involved in dissociation or atom transfer reactions. The variable kinetic function is first introduced in the framework of a classical 1DHR model. Then, an effective temperature and potential dependent constant is proposed in the cases of quantum 1DHR and classical d2DHR models. These methods are finally applied to the atom transfer reaction SiCl3+BCl3→SiCl4+BCl2. We show, for this particular case, that a proper accounting of internal rotations greatly improves the accuracy of thermodynamic and kinetic predictions. Moreover, our results confirm (i) that using a suitably defined kinetic function appears to be very adapted to such problems; (ii) that the separability assumption of independent rotations seems justified; and (iii) that a quantum mechanical treatment is not a substantial improvement with respect to a classical one.
Excited-state lifetime of adenine near the first electronic band origin
Authors: Kang Hyuk , Chang Jinyoung , Lee Sang Hak , Ahn Tae Kyu , Kim Nam Joon , Kim Seong Keun
Published: October 2010

The excited-state lifetime of supersonically cooled adenine was measured in the gas phase by femtosecond pump-probe transient ionization as a function of excitation energy between 36 100 and 37 500 cm−1. The excited-state lifetime of adenine is ∼2 ps around the 0-0 band of the L1b ππ∗ state (36 105 cm−1). The lifetime drops to ∼1 ps when adenine is excited to the L1a ππ∗ state with the pump energy at 36 800 cm−1 and above. The excited-state lifetimes of L1a and L1b ππ∗ states are differentiated in accordance with previous frequency-resolved and computational studies.
Making Sense of EU State Aid Requirements: The Case of Green Services
Authors: Zwaan Pieter , Goverde Henri
Published: October 2010

The concept of green services, developed in the Netherlands, aimed at rewarding activities by farmers in the field of nature and landscape management with a ‘market-based price’ provided by public and private actors. Despite a positive stance on the concept at member-state level, it took considerable efforts to get the concept implemented. The selected case, which is an exemplary case for a more general reorientation on the provision of agrienvironmental measures (eg in the context of the EU Common Agricultural Policy), shows that uncertainties of the EU state aid regime and complex power relationships within a multilevel governance setting led to much delay. We explain these difficulties by drawing from new-institutional and sense-making literature and the literature on escalation. We also show how a modus vivendi was found for establishing the green service concept and thereby provide insights for initiators of new agrienvironmental schemes or other horizontal modes of governance.
The Impact of Internal and External Characteristics on the Adoption of Climate Mitigation Policies by US Municipalities
Authors: Pitt Damian
Published: October 2010

Many US municipalities are engaged in climate mitigation planning, or efforts to reduce their communities' greenhouse gas (GHG) emissions through land-use, transportation, and energy planning. However, they face a number of procedural and institutional obstacles that limit the adoption and implementation of those plans. The literature identifies some of the factors that lead municipalities to join relevant policy networks, but provides little guidance for overcoming the aforementioned obstacles and adopting policies to reduce community-wide GHG emissions. With this study I increase the understanding of climate mitigation planning by examining whether the adoption of these plans and policies is driven primarily by local demographic, economic, environmental, or political – institutional characteristics. My research is based upon a survey of 255 US municipalities. I combine the survey responses with secondary data and use multiple regression techniques to estimate the impact of fifteen demographic, political – institutional, economic, and environmental variables on the adoption of climate mitigation plans and policies. The influence of neighboring jurisdictions, the presence of staff members assigned to energy or climate planning, and the level of community environmental activism are found to have the greatest impact on climate mitigation policy adoption. These findings support the conclusion that the extent of climate mitigation planning is driven primarily by internal processes, and municipalities that are successful in this area do not fit any one profile according to their demographic, economic, or environmental characteristics.
Giant panda habitat networks and conservation: is this species adequately protected?
Authors: Gong M. , Yang Z. , Yang W. , Song Y.
Published: October 2010

Context. Giant pandas (Ailuropoda melanoleuca) are restricted to six mountain ranges at the edge of the Tibetan Plateau. One of these ranges, the Qinling Mountains, contains the highest density of giant pandas and is home to ~20% of those remaining in the wild. Commercial logging and other developments have resulted in habitat fragmentation, and an efficient and powerful conservation network is now needed for the species in this area. Aims. This study sought to assess giant panda habitat and estimate the carrying capacity of this reserve network. Our goal was to improve the function and carrying capacity of the reserve network and facilitate population growth and gene flow among subpopulations of giant pandas. Methods. We use habitat suitability models to assess the efficacy of conservation networks. With estimation of carrying capacity by home range, we can reveal issues facing reserves and populations of endangered species they contain. Here, we define key habitat, linkages, corridors and overall connectivity and then use habitat network modelling and spatial analyses to design a conservation landscape for giant pandas across their Qinling Mountains stronghold. Key results. We found that 91% of giant panda sightings were in suitable or marginally suitable habitat. The total area of giant panda habitat present in the Qinling Mountains is ~1600 km2 fragmented across four key habitat blocks by national roads or other human activity. The current nature reserve network encompasses 71% of available suitable habitat and 62% of available marginal habitat, meaning a significant proportion of panda habitat remains outside the current conservation network. We found that giant panda reserves across this region are not equal in their carrying capacity; some reserves contain an overabundance of giant pandas and the wellbeing of these populations are in doubt. Conclusions. Our results highlight the potential risk of high densities and bamboo flowering events to the safety of giant pandas. With poor population size and heavy isolation, small populations will not persist without translocation. Implication. Redrawing the reserve network to correct localised problems may improve the function of the giant panda protection system, build capacity in the reserve network, and decrease human–wildlife conflict. We propose a new reserve and adjustment of the borders and region for three reserves.