bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential expression of human placental neurotrophic factors in preterm and term deliveries
Authors: Dhobale Madhavi V. , Pisal Hemlata R. , Mehendale Savita S. , Joshi Sadhana R.
Published: September 2013

Neurotrophic factors such as brain derived neurotrophic factor (BDNF) and nerve growth factor (NGF) are involved in development of the placenta and fetal brain. A series of human and animal studies in our department have shown that micronutrients (folic acid, vitamin B12) and omega 3 fatty acids like DHA are all interlinked in the one carbon cycle. Any alterations in one carbon components will lead to changes in methylation patterns that further affect the gene expression at critical periods of development resulting in complications during pregnancy. This may further contribute to risk for neurodevelopmental disorders in children born preterm. Therefore this study for the first time examines the mRNA levels from preterm and term placentae. A total number of 38 women delivering preterm (<37 weeks gestation) and 37 women delivering at term (=>37 weeks gestation) were recruited. The mRNA levels of BDNF and NGF were analyzed by real time quantitative polymerase chain reaction. Our results indicate that BDNF and NGF mRNA levels were lower in preterm group as compared to term group. There was a positive association of placental BDNF and NGF mRNA levels with cord plasma BDNF and NGF levels. The differential expression of BDNF and NGF gene in preterm placentae may also alter the vascular development in preterm deliveries. Our data suggests that the reduced mRNA levels of BDNF and NGF may possibly be a result of altered epigenetic mechanisms and may have an implication for altered fetal programming in children born preterm.
Cold War redux in US–Russia relations? The effects of US media framing and public opinion of the 2008 Russia–Georgia war
Authors: Bayulgen Oksan , Arbatli Ekim
Published: September 2013

This paper examines the Cold War rhetoric in US–Russia relations by looking at the 2008 Russia–Georgia war as a major breaking point. We investigate the links between media, public opinion and foreign policy. In our content analysis of the coverage in two major US newspapers, we find that the framing of the conflict was anti-Russia, especially in the initial stages of the conflict. In addition, our survey results demonstrate that an increase in the media exposure of US respondents increased the likelihood of blaming Russia exclusively in the conflict. This case study helps us understand how media can be powerful in constructing a certain narrative of an international conflict, which can then affect public perceptions of other countries. We believe that the negative framing of Russia in the US media has had important implications for the already-tenuous relations between the US and Russia by reviving and perpetuating the Cold War mentality for the public as well as for foreign policymakers.
Interplay of magmatism, sedimentation, and collision processes in the Siberian craton and the flanking orogens
Authors: Dobretsov N.L. , Buslov M.M. , De Grave J. , Sklyarov E.V.
Published: September 2013

The interplay of geodynamic and sedimentation processes in the Central Asian orogen and the Siberian craton is discussed in several aspects: (i) general tectonics of the Central Asian orogen, (ii) correlation of deposition and collision events, (iii) deposition history and sediment sources on the northern and eastern margins of the Siberian craton, compared, and (iv) history of the Central Asian orogen (Altaids) and formation of Early Mesozoic sedimentary basins.

Chemical and isotope compositions and geochronology of Neoproterozoic–Paleozoic sedimentary sequences indicate deposition synchronicity in basins of different types, within both the craton and the orogen. Thus geodynamic models of deposition in separate basins provide reliable evidence of the history of orogens flanking the Siberian craton.

The study has confirmed the existence of the Vendian–Early Paleozoic Charysh–Terekta–Ulagan–Sayan–Olkhon strike-slip suture between the continental-margin complexes of Siberia and Kazakhstan, with the crust of juvenile and mixed types, respectively. Late Paleozoic large-scale strike-slip faulting deformed the previous tectonic framework and caused tectonic mixing of the older structures on different margins. This superposed deformation makes it difficult to decipher the paleogeography, paleotectonics, and paleogeodynamics of the Central Asian orogen.
Early evolution of the Paleoasian ocean: LA-ICP-MS dating of detrital zircon from Late Precambrian sequences of the southern margin of the Siberian craton
Authors: Gladkochub D.P. , Stanevich A.M. , Mazukabzov A.M. , Donskaya T.V. , Pisarevsky S.A. , Nicoll G. , Motova Z.L. , Kornilova T.A.
Published: September 2013

We present U–Pb (LA-ICP-MS) data on detrital zircon from the Late Precambrian terrigenous rocks of the Baikal Group and Ushakovka Formation, western Cisbaikalia (southern flank of the Siberian craton). The sources of clastic material for the studied sediments are interpreted. The youngest group of detrital zircon grains from the upper Baikal Group and Ushakovka Formation permits assigning these sediments to the Vendian. The lack of Mesoproterozoic detrital zircon in most of the analyzed samples confirms the hypothesis of a global (~1 Gyr) break in endogenic activity within the southern flank of the Siberian craton through the Precambrian. The abundance of Neoproterozoic zircon in sandstones from the upper horizons of the Baikal Group and the Ushakovka Formation might be due to the shrinkage of the ocean basin as a result of the convergence of the craton with the microcontinents and island arcs within the Paleoasian ocean.
The Vendian passive continental margin in the southern Siberian Craton: geochemical and isotopic (Sr, Sm–Nd) evidence and U–Pb dating of detrital zircons by the LA-ICP-MS method
Authors: Letnikova E.F. , Kuznetsov A.B. , Vishnevskaya I.A. , Veshcheva S.V. , Proshenkin A.I. , Geng H.
Published: September 2013

Geochemical and isotopic (Sm–Nd and Sr) studies of deposits of the Baikal and Oselok Groups in the southern Siberian Craton and LA-ICP-MS U–Pb dating of detrital zircons show that they accumulated in passive continental-margin settings in the Vendian. The time limits of sedimentation were assessed on the basis of Sr chemostratigraphy of carbonate deposits of the Baikal Group and LA-ICP-MS U–Pb dating of detrital zircons in first-cycle terrigenous deposits of the Oselok Group. The main provenances for rocks of these groups were constant. These were rocks of the cover and basement of the Siberian Craton. Tuffite horizons in upper portions of the groups are the only sign of Late Vendian activation of this block, which is reflected in changes of geochemical indices of terrigenous rocks and their younger Sm–Nd model ages.
Late Quaternary fluvial terraces near the Daocheng Ice Cap, eastern Tibetan Plateau
Authors: Xu Liubing , Zhou Shangzhe
Published: September 2013

The timing of terrace formation relative to the glacial–interglacial cycle and what factors control that timing, such as changes in climate and/or uplift, are controversial. Here we present a study of the terraces along the Yazheku River using electron spin resonance (ESR) dating and analysis of the sedimentary characteristics in order to establish the timing of terrace formation and to assess the forcing mechanisms that have been proposed. The Yazheku River flows in glacial trough leading from the Haizi Shan, on the eastern Tibetan Plateau. The range was uplifted during the Quaternary and repeatedly glaciated by ice caps. The four highest major terraces (T5, T4, T3, and T2) are the result of both climatic and tectonic influences. Strath terraces T5–T2 were created during Haizi Shan glacial expansions during MIS 16, 12, 6 and 3–4, respectively. The major aggradation phases of the four terraces occurred during the deglaciations at the ends of MIS 16, 12, 6, and 2. Down-cutting, which led to the generation of the four terraces, immediately followed the deposition of the T5–T2 gravel units. These incisions occurred during the transitions between MIS 16–15, MIS 12–11, MIS 6–5, and MIS 2–1.
Influence of aspect ratio on tumbling plates
Authors: Wang W. B. , Hu R. F. , Xu S. J. , Wu Z. N.
Published: September 2013

The tumbling motion of freely falling plates with aspect ratio ranging from 2 to 10 is studied using both experimental measurement and simplified lifting line theory. The trajectories of plates are recorded by high-speed video camera and analysed to obtain instantaneous and average kinematic and aerodynamic parameters, including the descent angle, rotating speed, descent velocities, lift and drag coefficients, and their fluctuation spectrums. A double period rotation with period doubling is observed here for some range of aspect ratio and the double frequency is determined from a Fourier analysis. By adding a correction from the inducing effect of trailing vortices and wing-tip vortices to the corresponding two-dimensional force and torque expressions, a simplified kinematic model is obtained which successfully predicts the qualitative influence of aspect ratio on the averaged kinematics, that the descent angle and the vertical descent velocity component are decreasing functions of the aspect ratio, while the rotation speed and horizontal velocity component are increasing functions of the aspect ratio. For decreasing aspect ratio, the induced drag due to the trailing and tip vortices reduces the lift to drag ratio and thus increases the descent angle, while the dissipative torque due to translational induced drag decreases the rotation speed.
Oil and Autocratic Regime Survival
Authors: Wright Joseph , Frantz Erica , Geddes Barbara
Published: September 2013

This article uncovers a new mechanism linking oil wealth to autocratic regime survival: the investigation tests whether increases in oil wealth improve the survival of autocracies by lowering the chances of democratization, reducing the risk of transition to subsequent dictatorship, or both. Using a new measure of autocratic durability shows that, once models allow for unit effects, oil wealth promotes autocratic survival by lowering the risk of ouster by rival autocratic groups. Evidence also indicates that oil income increases military spending in dictatorships, which suggests that increasing oil wealth may deter coups that could have caused a regime collapse.
Excavating the Roman peasant II: excavations at Case Nuove, Cinigiano (GR)
Authors: Vaccaro Emanuele , Ghisleni Mariaelena , Arnoldus-Huyzendveld Antonia , Grey Cam , Bowes Kim , MacKinnon Michael , Mercuri Anna Maria , Pecci Alessandra , Cau Ontiveros Miguel Ángel , Rattigheri Eleonora , Rinaldi Rossella
Published: September 2013

This report details the survey, excavations and materials analysis carried out at Case Nuove (GR) in Tuscany, a site identified by surface survey as a possible rural house, but which excavation and materials analysis suggest was a small-scale agro-processing point of late Republican date. Through accompanying analysis of pollen and land-use data, the article considers the problems this type of site — the stand-alone agro-processing point — presents for interpretations of the Roman landscape.
Imaging the Golden Age: the coinage of Antoninus Pius
Authors: Rowan Clare
Published: September 2013

Given that few ancient accounts of the reign of Antoninus Pius survive from antiquity, other monuments, in particular coinage, become important in reconstructing his reign. In this article coin hoards are used to reconstruct a quantitative understanding of Pius's numismatic imagery. It is clear from the results that the three different coin metals (gold, silver andaes) differed in their messages: while gold coinage emphasized the imperial family and the concept ofpietas, silver andaescoinage focused on the emperor's concern for the grain supply (annona). This broad understanding of Pius's numismatic image is supplemented by more detailed analysis of coin iconography in particular years. Theliberalitasand Britannia series of Pius are explored in depth. The study highlights coinage's role as one imperial monument among many, contributing to the communication of imperial ideologies. It is clear that the image of Pius as a virtuous emperor ruling in a ‘Golden Age’ was one cultivated by the imperial bureaucracy, and so it is not surprising that the concept features in the preserved texts. The long-term impact of Pius's coinage is also considered. In the absence of significant quantities ofaescoinage struck by the Severans, the coinage of Pius continued to be of importance in many regions throughout the third century, conveying impressions of Empire among users well after the emperor's death.
Herculaneum from thead79 eruption to the medieval period: analysis of the documentary, iconographic and archaeological sources, with new data on the beginning of exploration at the ancient town
Authors: Camardo Domenico
Published: September 2013

This article, divided into two main parts, first analyses the archaeological data for a return to the site of Herculaneum after its destruction in thead79 eruption. The evidence includes a necropolis above the Roman town, along with burials and other finds in the Herculaneum area up to the late antique period. The second part looks at how the medieval settlement of Resina grew up over ancient Herculaneum and how new archaeological research has demonstrated that tunnelling was already being carried out to retrieve marble and building materials from the Roman town in the fourteenth century. This occurred sporadically, but it seems to have continued, without being continuous, through the subsequent centuries and pre-dates by several centuries the so-called ‘re-discovery’ of Herculaneum in 1710, which took place over twenty years before the beginning of systematic excavations in 1738.
Notes from Rome 2012–13
Authors: Coates-Stephens Robert
Published: September 2013

This gazette presents to the reader outside Rome news of recent archaeological activity (primarily in 2012, but also in the first part of 2013), gleaned from public lectures, conferences, exhibitions and newspaper reports.
Decrease in the incidence of culture-positive meningitis and cerebral tuberculomas in France from 1990 to 2007
Authors: BUI T. V. , MEYSSONNIER V. , BOELLE P. Y. , CHE D. , ANTOINE D. , JARLIER V. , ROBERT J.
Published: September 2013

We evaluated the incidence rate of culture-positive central nervous system tuberculosis (CNS TB) in France in 2007 and its time trend between 1990 and 2007. We used a capture–recapture analysis by using data recorded in 2007 by the mandatory notification system and the national network of the National Reference Centre (NRC). The 2007 sensitivity of the NRC was 79·4%. The previous sensitivity for 2000 (75·6%) and that for 2007 yielded a pooled estimate of 77·4% (95% confidence interval 64·8–88·0), which was used to extrapolate the number of culture-positive CNS TB cases from those reported in four surveys (1990, 1995, 2000, 2007). The extrapolated number of culture-positive CNS TB cases fell from 90 to 35 between 1990 and 2007, and the extrapolated incidence rates fell from 1·6 to 0·55 cases/million (P < 0·001). This favourable trend should be closely monitored following the change of the BCG vaccination policy in 2007.
Response to farmer mass selection in early generation progeny of bread wheat landrace crosses
Authors: Rivière Pierre , Goldringer Isabelle , Berthellot Jean-François , Galic Nathalie , Pin Sophie , De Kochko Patrick , Dawson Julie C.
Published: September 2013

A participatory plant breeding (PPB) program involving the French farmers' association ‘Réseau Semences Paysannes’ and the French National Agricultural Research Institute (INRA) at Le Moulon was initiated in 2005. In the process of designing the breeding scheme, we evaluated the impact of farmer selection at an early stage (F2) on bread wheat cross progeny populations. The objectives were to characterize the effect of farmer selection, to evaluate the impact of farmer selection on intra-varietal diversity, to provide farmers with relevant information that they can use to improve their selection practices. Early selection was found efficient for some traits and for some of the 35 F2-derived F3 families. For traits of interest such as thousand kernel weight or grain weight per spike, when the response was significant, it was always positive. For most of the traits studied, the among-family genetic variance increased after selection while the average within-family genetic variance decreased. This study provides the first quantitative results for this PPB program and information that will help optimize it in the future.
Suicides in Urban and Rural Counties in the United States, 2006–2008
Authors: Searles Veronica B. , Valley Morgan A. , Hedegaard Holly , Betz Marian E.
Published: September 2013

Background: Suicide rates are higher in rural areas. It has been hypothesized that inadequate access to care may play a role, but studies examining individual decedent characteristics are lacking. Aims: We sought to characterize the demographic, socioeconomic, and mental health features of individual suicide decedents by urban–rural residence status. Method: We analyzed suicides in 16 states using 2006–2008 data from the National Violent Death Reporting System and examined associations between decedent residence type and suicide variables with separate logistic regressions adjusted for age, sex, race, and ethnicity. Results: Of 17,504 analyzed suicides, 78% were in urban, 15% in rural adjacent, and 8% in rural nonadjacent locations. Rural decedents were less likely than urban decedents to have a mental health diagnosis or mental health care, although the prevalence of depressed moods appeared similar. Most suicides were by firearm, and rural decedents were more likely than urban decedents to have used a firearm. Conclusion: Rural decedents were less likely to be receiving mental health care and more likely to use firearms to commit suicide. A better understanding of geographic patterns of suicide may aid prevention efforts.
Linking N2O emissions from biochar-amended soil to the structure and function of the N-cycling microbial community
Authors: Harter Johannes , Krause Hans-Martin , Schuettler Stefanie , Ruser Reiner , Fromme Markus , Scholten Thomas , Kappler Andreas , Behrens Sebastian
Published: September 2013

Nitrous oxide (N2O) contributes 8% to global greenhouse gas emissions. Agricultural sources represent about 60% of anthropogenic N2O emissions. Most agricultural N2O emissions are due to increased fertilizer application. A considerable fraction of nitrogen fertilizers are converted to N2O by microbiological processes (that is, nitrification and denitrification). Soil amended with biochar (charcoal created by pyrolysis of biomass) has been demonstrated to increase crop yield, improve soil quality and affect greenhouse gas emissions, for example, reduce N2O emissions. Despite several studies on variations in the general microbial community structure due to soil biochar amendment, hitherto the specific role of the nitrogen cycling microbial community in mitigating soil N2O emissions has not been subject of systematic investigation. We performed a microcosm study with a water-saturated soil amended with different amounts (0%, 2% and 10% (w/w)) of high-temperature biochar. By quantifying the abundance and activity of functional marker genes of microbial nitrogen fixation (nifH), nitrification (amoA) and denitrification (nirK, nirS and nosZ) using quantitative PCR we found that biochar addition enhanced microbial nitrous oxide reduction and increased the abundance of microorganisms capable of N2-fixation. Soil biochar amendment increased the relative gene and transcript copy numbers of the nosZ-encoded bacterial N2O reductase, suggesting a mechanistic link to the observed reduction in N2O emissions. Our findings contribute to a better understanding of the impact of biochar on the nitrogen cycling microbial community and the consequences of soil biochar amendment for microbial nitrogen transformation processes and N2O emissions from soil.
The CCHamide 1 receptor modulates sensory perception and olfactory behavior in starved Drosophila
Authors: Farhan Abu , Gulati Jyotasana , Groβe-Wilde Ewald , Vogel Heiko , Hansson Bill S. , Knaden Markus
Published: September 2013

The olfactory response of the vinegar fly Drosophila melanogaster to food odor is modulated by starvation. Here we show that this modulation is not restricted to food odors and their detecting sensory neurons but rather increases the behavioral response to odors as different as food odors, repellents and pheromones. The increased behavioral responsiveness is paralleled by an increased physiological sensitivity of sensory neurons regardless whether they express olfactory or ionotropic receptors and regardless whether they are housed in basiconic, coeloconic, or trichoid sensilla. Silencing several genes that become up-regulated under starvation confirmed the involvement of the short neuropeptide f receptor in the starvation effect. In addition it revealed that the CCHamide-1 receptor is another important factor governing starvation-induced olfactory modifications.
Manageable N-doped Graphene for High Performance Oxygen Reduction Reaction
Authors: Zhang Yuewei , Ge Jun , Wang Lu , Wang Donghong , Ding Feng , Tao Xiaoming , Chen Wei
Published: September 2013

Catalysts for oxygen reduction reaction (ORR) are at the heart of key green-energy fuel cell technology. N-doped graphene is a potential metal-free electrode with much better electrocatalytic activity, long-term stability and tolerance to crossover effect than expensive platinum-based electrocatalysts. Here, we report a feasible direct-synthesis method in preparing N-graphene with manageable N contents in a large scale. The resultant N-graphene used as electrocatalysts exhibits similar catalytic activity but superior stability compared to commercial Pt/C for ORR in an alkaline solution. It was found that their electrocatalytic activities were demonstrated to depend largely on N-doping content. When nitrogen content reaches a high value at about 24–25%, ORR reaction exhibits a favorable formation of water via a four-electron pathway. Furthermore, the effect of pyrolysis temperature and precursor on the activity of N-graphene is systematically analyzed and may shed some light on the principle of choosing appropriate way for preparing N-graphene.
Green tea polyphenol decreases the severity of portosystemic collaterals and mesenteric angiogenesis in rats with liver cirrhosis
Authors: Hsu Shao-Jung , Wang Sun-Sang , Hsin I-Fang , Lee Fa-Yauh , Huang Hui-Chun , Huo Teh-Ia , Lee Wen-Shin , Lin Han-Chieh , Lee Shou-Dong
Published: September 2013

Abnormal angiogenesis in liver cirrhosis often leads to severe complications such as variceal haemorrhage and encephalopathy. Furthermore, splanchnic angiogenesis elevates portal pressure, in which angiogenic factors play pivotal roles. GTP (green tea polyphenol) extracted from Camellia sinensis has anti-angiogenic properties, but the effects on the parameters described above in cirrhosis have not been investigated. The aim of the present study was to determine the effects of GTP in cirrhosis and to investigate the underlying mechanism. Liver cirrhosis was induced in Spraque–Dawley rats by common BDL (bile duct ligation). They randomly received GTP or DW (distilled water, vehicle) for 28 days, then haemodynamic parameters, portosystemic shunting, mesenteric window vascular density, intrahepatic angiogenesis, liver fibrosis, plasma VEGF (vascular endothelial growth factor) concentration, mesenteric angiogenic factor and receptor protein expression, and serum and mesenteric oxidative stress parameters were assessed. Compared with the DW group, GTP significantly decreased portosystemic shunting, liver fibrosis, intrahepatic angiogenesis, mesenteric window vascular density, VEGF concentration and down-regulated the mesenteric HIF (hypoxia-inducible factor)-1α, VEGF and phospho-Akt expression. In conclusion, GTP ameliorates the severity of portosystemic shunting and mesenteric angiogenesis via the suppression of HIF-1α, Akt activation and VEGF. GTP appears to be an appropriate agent in controlling portal hypertension-related complications via anti-angiogenesis.
Multi‐level fuzzy contourlet‐based image fusion for medical applications
Authors: Darwish Saad M.
Published: September 2013

Multi‐modal images fusion is one of the most truthful and useful diagnostic techniques in medical imaging system. This study proposes an image fusion system for medical engineering based on contourlet transform and multi‐level fuzzy reasoning technique in which useful information from two spatially registered medical images is integrated into a new image that can be used to make clinical diagnosis and treatment more accurate. The system applies pixel‐based fuzzy fusion rule to contourlet's coefficients of high‐frequency details and feature‐based fuzzy fusion to its low‐frequency approximations, which can help the development of sophisticated algorithms that consider not only the time cost but also the quality of the fused image. The developed fusion system eliminates undesirable effects such as fusion artefacts and loss of visually vital information that compromise their usefulness by means of taking into account the physical meaning of contourlet coefficients. The experimental results show that the proposed fusion system outperforms the existing fusion algorithms and is effective to fuse medical images from different sensors with applications in brain image processing.
Coherent angle estimation in bistatic multi‐input multi‐output radar using parallel profile with linear dependencies decomposition
Authors: Chen Chen , Zhang Xiaofei , Ben De
Published: September 2013

This study investigates the topic of coherent angle estimation in bistatic multi‐input multi‐output (MIMO) radar, and derives a scheme for coherent angle estimation by exploiting a parallel profile with linear dependencies (PARALIND) decomposition. The receive data can be mapped to a PARALIND model, after which the estimations of transmit/receive directional matrices and the correlated matrix of the sources are all obtained through PARALIND decomposition. Finally, the estimates of direction of departures and direction of arrivals can be obtained by least‐square principle. In contrast to the forward–backward spatial smoothing‐propagator (FBSS) method and FBSS‐estimation method of signal parameters via rotational invariance techniques algorithms, the proposed method not only reaches paired estimates of the angles automatically but also has much better performance for angle estimation. On the other hand, our algorithm can be used for angle estimation in non‐uniform linear transmit/receive array. Simulations present the effectiveness of our approach.
Femtosecond x-ray absorption spectroscopy with hard x-ray free electron laser
Authors: Katayama Tetsuo , Inubushi Yuichi , Obara Yuki , Sato Takahiro , Togashi Tadashi , Tono Kensuke , Hatsui Takaki , Kameshima Takashi , Bhattacharya Atanu , Ogi Yoshihiro , Kurahashi Naoya , Misawa Kazuhiko , Suzuki Toshinori , Yabashi Makina
Published: September 2013

We have developed a method of dispersive x-ray absorption spectroscopy with a hard x-ray free electron laser (XFEL), generated by a self-amplified spontaneous emission (SASE) mechanism. A transmission grating was utilized for splitting SASE-XFEL light, which has a relatively large bandwidth (ΔE/E ∼ 5 × 10−3), into several branches. Two primary split beams were introduced into a dispersive spectrometer for measuring signal and reference spectra simultaneously. After normalization, we obtained a Zn K-edge absorption spectrum with a photon-energy range of 210 eV, which is in excellent agreement with that measured by a conventional wavelength-scanning method. From the analysis of the difference spectra, the noise ratio was evaluated to be ∼3 × 10−3, which is sufficiently small to trace minute changes in transient spectra induced by an ultrafast optical laser. This scheme enables us to perform single-shot, high-accuracy x-ray absorption spectroscopy with femtosecond time resolution.
Molecular simulation of aqueous electrolytes: Water chemical potential results and Gibbs-Duhem equation consistency tests
Authors: Moučka Filip , Nezbeda Ivo , Smith William R.
Published: September 2013

This paper deals with molecular simulation of the chemical potentials in aqueous electrolyte solutions for the water solvent and its relationship to chemical potential simulation results for the electrolyte solute. We use the Gibbs-Duhem equation linking the concentration dependence of these quantities to test the thermodynamic consistency of separate calculations of each quantity. We consider aqueous NaCl solutions at ambient conditions, using the standard SPC/E force field for water and the Joung-Cheatham force field for the electrolyte. We calculate the water chemical potential using the osmotic ensemble Monte Carlo algorithm by varying the number of water molecules at a constant amount of solute. We demonstrate numerical consistency of these results in terms of the Gibbs-Duhem equation in conjunction with our previous calculations of the electrolyte chemical potential. We present the chemical potential vs molality curves for both solvent and solute in the form of appropriately chosen analytical equations fitted to the simulation data. As a byproduct, in the context of the force fields considered, we also obtain values for the Henry convention standard molar chemical potential for aqueous NaCl using molality as the concentration variable and for the chemical potential of pure SPC/E water. These values are in reasonable agreement with the experimental values.
Parity-dependent oscillations in collisional polarization transfer: CN(A2Π, v = 4) + Ar
Authors: McGurk S. J. , McKendrick K. G. , Costen M. L. , Alexander M. H. , Dagdigian P. J.
Published: September 2013

We report the first systematic experimental and theoretical study of the state-to-state transfer of rotational angular momentum orientation in a 2Π-rare gas system. CN(X2Σ+) was produced by pulsed 266 nm photolysis of ICN in a thermal bath (296 K) of Ar collider gas. A pulsed circularly polarized tunable dye laser prepared CN(A2Π, v = 4) in two fully state-selected initial levels, j = 6.5 F1e and j = 10.5 F2f, with a known laboratory-frame orientation. Both the prepared levels and a range of product levels, j′ F1e and j′ F2f, were monitored using the circular polarized output of a tunable diode laser via cw frequency-modulated (FM) spectroscopy in stimulated emission on the CN(A-X) (4,2) band. The FM Doppler lineshapes for co-rotating and counter-rotating pump-and-probe geometries reveal the time-dependence of the populations and orientations. Kinetic fitting was used to extract the state-to-state population transfer rate constants and orientation multipole transfer efficiencies (MTEs), which quantify the degree of conservation of initially prepared orientation in the product level. Complementary full quantum scattering (QS) calculations were carried out on recently computed ab initio potential energy surfaces. Collision-energy-dependent tensor cross sections for ranks K = 0 and 1 were computed for transitions from both initial levels to all final levels. These quantities were integrated over the thermal collision energy distribution to yield predictions of the experimentally observed state-to-state population transfer rate constants and MTEs. Excellent agreement between experiment and theory is observed for both measured quantities. Dramatic oscillations in the MTEs are observed, up to and including changes in the sign of the orientation, as a function of even/odd Δj within a particular spin-orbit and e/f manifold. These oscillations, along with those also observed in the state-to-state rate constants, reflect the rotational parity of the final level. In general, parity-conserving collisions conserve rotational orientation, while parity-changing collisions result in large changes in the orientation. The QS calculations show that the dynamics of the collisions leading to these different outcomes are fundamentally different. We propose that the origin of this behavior lies in interferences between collisions that sample the even and odd-λ terms in the angular expansions of the PESs.
Convergence and low temperature adaptability analysis of the high temperature series expansion of the free energy
Authors: Zhou Shiqi
Published: September 2013

By appealing to the coupling parameter series expansion to calculate the first seven perturbation coefficients of the high temperature series expansion (HTSE) of the free energy, analysis of convergence and low temperature adaptability of the HTSE in calculating fluid thermodynamic properties is performed for the first time; the fluid thermodynamic properties considered include critical parameters, vapor-liquid coexistence curve, thermodynamic characteristic functions, chemical potential, pressure, and constant volume excess heat capacity. To proceed with the analysis, a well known square well model is used as sample; the well widths considered range over a wide interval, and the relevant temperatures amenable to simulation calculations (used as “exact” results to analyze the HTSE) can be both very high and very low. The main discoveries reached are summarized as follows: (1) The HTSE usually converges at the 4th-order truncation, but with decrease of the temperature considered, the lowest truncation order, which makes the HTSE to converge, tends to rise. As a conservative estimate, it is considered that the HTSE always converges for reduced temperature T* higher than 0.25, whereas for T* < 0.25 there appear signs indicating that the HTSE may diverge from the 7th-order truncation. (2) Within the temperature interval with T* ⩾ 0.5, the HTSE converges approximately to the correct solution, and the HTSE can be reliably used to calculate the fluid thermodynamic properties, and within this temperature interval, the 4th-order truncation is enough; whereas for T* < 0.5, such as within the temperature interval with 0.275 ⩽ T* ⩽ 0.355, although the HTSE does converge, it does not converge to the correct solution, and the deviations between the HTSE calculations and MC simulations become an ever-prominent issue with the rising of the density, and the slopes of the thermodynamic properties over density are not satisfactorily represented. As a result, the HTSE is not suited for calculations for temperature interval T* < 0.5.
Self-similar vortex dynamics in superfluid 4He under the Cartesian representation of the Hall-Vinen model including superfluid friction
Authors: Van Gorder Robert A.
Published: September 2013

We determine conditions under which the fully nonlinear form of the local induction approximation (LIA) governing the motion of a vortex filament in superfluid 4He (that is, the Hall-Vinen model) in the Cartesian frame of reference permits the existence of self-similar solutions, even in the presence of superfluid friction parameters. Writing the Cartesian Hall-Vinen LIA in potential form for the motion of a vortex filament, we find that a necessary condition for self-similarity is that the normal-fluid component vanishes (which makes sense in the low temperature limit), and we reduce the potential form of the Hall-Vinen LIA to a complex nonlinear ordinary differential equation governing the behavior of a similarity solution. In the limit where superfluid friction parameters are negligible, we provide some analytical and asymptotic results for various regimes. While such analytical results are useful for determining the qualitative behavior of the vortex filament in the limit where superfluid friction parameters vanish, numerical simulations are needed to determine the true behavior of the filaments in the case of non-zero superfluid friction parameters. While the superfluid friction parameters are small, the numerical results demonstrate that the influence of the superfluid friction parameters on the self-similar vortex structures can be strong. We classify two types of filaments from the numerical results: singular filaments (which demonstrate growing oscillations and hold kink-type solutions as a special case) and bounded filaments (whose behavior is a bounded function of x). We also comment on how to include the case where there is a non-zero normal fluid, and we find a transformation of the self-similar solutions into non-similar solutions that can account for this.
The effect of the H2 density on the electron energy distribution in H− ion sources
Authors: Wang Huihui , Meng Lin , Liu Dagang , Liu Laqun , Yang Chao
Published: September 2013

The electron energy distribution in H− ion sources is studied. By three-dimensional Monte Carlo simulations (3D-MCC) and cross sections of collisions, the crucial collisions in the JAEA 10A are chosen to develop theoretical models for the low electron temperature and the high electron temperature, respectively. The effects of the H2 density on the low electron temperature and the high electron temperature in H− ion sources are predicted with analytic expressions and verified by 3D-MCC. The results show that both the low and high electron temperatures become lower while nH2 increases.
A comparison of parametric decay of oblique Langmuir wave in high and low density magneto-plasmas
Authors: Shahid M. , Hussain A. , Murtaza G.
Published: September 2013

The parametric decay instability of an obliquely propagating Langmuir wave into the low-frequency electromagnetic shear Alfven wave and the Left-Handed Circularly Polarized wave has been investigated in an electron-ion plasma, immersed in a uniform external magnetic field. Quantum magneto-hydrodynamic model has been used to find the linear and non-linear response of a high density quantum magneto-plasma. Going to the classical limit (ℏ→0) retrieves the results for low density classical plasma. Nonlinear dispersion relations and growth rates are derived with analytically and numerically. It is observed that growth rate in the high density degenerate magneto-plasma increases exponentially, while in the low density classical case it increases logarithmically.
Thermally activated in-plane magnetization rotation induced by spin torque
Authors: Chotorlishvili L. , Toklikishvili Z. , Sukhov A. , Horley P. P. , Dugaev V. K. , Vieira V. R. , Trimper S. , Berakdar J.
Published: September 2013

We study the role of thermal fluctuations on the spin dynamics of a thin permalloy film with a focus on the behavior of spin torque and find that the thermally assisted spin torque results in new aspects of the magnetization dynamics. In particular, we uncover the formation of a finite, spin torque-induced, in-plane magnetization component. The orientation of the in-plane magnetization vector depends on the temperature and the spin-torque coupling. We investigate and illustrate that the variation of the temperature leads to a thermally induced rotation of the in-plane magnetization.
Giant optical field enhancement in multi-dielectric stacks by photon scanning tunneling microscopy
Authors: Ndiaye C. , Zerrad M. , Lereu A. L. , Roche R. , Dumas Ph. , Lemarchand F. , Amra C.
Published: September 2013

Dielectric optical thin films, as opposed to metallic, have been very sparsely explored as good candidates for absorption-based optical field enhancement. In such materials, the low imaginary part of the refractive index implies that absorption processes are usually not predominant. This leads to dielectric-based optical resonances mainly via waveguiding modes. We show here that when properly designed, a multi-layered dielectric thin films stack can give rise to optical resonances linked to total absorption. We report here, on such dielectric stack designed to possess a theoretical optical field enhancement above 1000. Using photon scanning tunneling microscopy, we experimentally evaluate the resulting field enhancement of the stack as well as the associated penetration depth. We thus demonstrate the capability of multi-dielectric stacks in generating giant optical field with tunable penetration depth (down to few dozens of nm).
Electride mediated surface enhanced Raman scattering
Authors: Anderson Mark S.
Published: September 2013

A ceramic electride is demonstrated to provide surface enhanced Raman scattering. The electride, an ionic crystal where the electrons serve as anions, is a conductive ceramic derived from mayenite. The textured electride surface was found to strongly enhance the Raman scattering of an organic analyte at 532 nm and 785 nm excitation wavelengths. This provides a sensitive method for monitoring the chemistry and electronic environment at the electride surface. The results are evidence of a surface electride-polariton resonance mechanism that is analogous to the surface plasmon-polariton resonance that mediates conventional surface enhance Raman scattering.
Suppression of the quantum-confined Stark effect in AlxGa1−xN/AlyGa1−yN corrugated quantum wells
Authors: Toropov A. A. , Shevchenko E. A. , Shubina T. V. , Jmerik V. N. , Nechaev D. V. , Yagovkina M. A. , Sitnikova A. A. , Ivanov S. V. , Pozina G. , Bergman J. P. , Monemar B.
Published: September 2013

We report comparative studies of 6-nm-thick AlxGa1−xN/AlyGa1−yN pyroelectric quantum wells (QWs) grown by plasma-assisted molecular beam epitaxy on c-sapphire substrates with a thick AlN buffer deposited under different growth conditions. The Al-rich growth conditions result in a 2D growth mode and formation of a planar QW, whereas the N-rich conditions lead to a 3D growth mode and formation of a QW corrugated on the size scale of 200–300 nm. Time-resolved photoluminescence (PL) measurements reveal a strong quantum-confined Stark effect in the planar QW, manifested by a long PL lifetime and a red shift of the PL line. In the corrugated QW, the emission line emerges 200 meV higher in energy, the low-temperature PL lifetime is 40 times shorter, and the PL intensity is stronger (∼4 times at 4.5 K and ∼60 times at 300 K). The improved emission properties are explained by suppression of the quantum-confined Stark effect due to the reduction of the built-in electric field within the QW planes, which are not normal to the [0001] direction, enhanced carrier localization, and improved efficiency of light extraction.
Abnormal threshold voltage shift under hot carrier stress in Ti1−xNx/HfO2 p-channel metal-oxide-semiconductor field-effect transistors
Authors: Tsai Jyun-Yu , Chang Ting-Chang , Lo Wen-Hung , Ho Szu-Han , Chen Ching-En , Chen Hua-Mao , Tseng Tseung-Yuen , Tai Ya-Hsiang , Cheng Osbert , Huang Cheng-Tung
Published: September 2013

This work investigates the channel hot carrier (CHC) effect in HfO2/Ti1−xNx p-channel metal oxide semiconductor field effect transistors (p-MOSFETs). Generally, the subthreshold swing (S.S.) should increase during CHC stress (CHCS), since interface states will be generated near the drain side under high electric field due to drain voltage (Vd). However, our experimental data indicate that S.S. has no evident change under CHCS, but threshold voltage (Vth) shifts positively. This result can be attributed to hot carrier injected into high-k dielectric near the drain side. Meanwhile, it is surprising that such Vth degradation is not observed in the saturation region during stress. Therefore, drain-induced-barrier-lowering (DIBL) as a result of CHC-induced electron trapping is proposed to explain the different Vth behaviors in the linear and saturation regions. Additionally, the influence of different nitrogen concentrations in HfO2/Ti1−xNx p-MOSFETs on CHCS is also investigated in this work. Since nitrogen diffuses to SiO2/Si interface induced pre-Nit occurring to degrades channel mobility during the annealing process, a device with more nitrogen shows slightly less impact ionization, leading to insignificant charge trapping-induced DIBL behavior.
A white light interferometric microscope for measuring dose-dependent reversible photodegradation
Authors: Anderson Benjamin , Bernhardt Elizabeth , Kuzyk Mark G.
Published: September 2013

We have developed a white light interferometric microscope (WLIM), which can spatially resolve the change in the complex index of refraction and apply it to study reversible photodegradation of 1,4-Diamino-9,10-anthraquinone doped into (poly)methyl-methacrylate. The measured change in absorbance is consistent with standard spectrometer measurements. The refractive index of a pristine sample measured with the WLIM is also found to be consistent with the spectrum found by independent means [F. Yakuphanoglu and B. Senkal, “Electrical conductivity, photoconductivity, and optical properties of poly(1,4-diaminoanthraquinone) organic semiconductor for optoelectronic applications,” Polym. Adv. Technol. 19, 1193–1198 (2008)]. We report on measurements of the change in refractive index due to photodegradation, which is found to be consistent with Embaye's two-population model [N. Embaye et al., “Mechanisms of reversible photodegradation in disperse orange 11 dye doped in PMMA polymer,” J. Chem. Phys. 129, 054504 (2008)]. We show that the WLIM can be used as a powerful tool to image the complex refractive index of a planar surface and to detect changes in a material's optical properties.
Cell viability monitoring using Fano resonance in gold nanoslit array
Authors: Wu Shu-Han , Hsieh Shu-Yi , Lee Kuang-Li , Weng Ruei-Hung , Chiou Arthur , Wei Pei-Kuen
Published: September 2013

Cell viability is a crucial issue in biological research. We present label-free monitoring of adhesion cells viability by gold nanoslits-based Fano resonance biosensors. Plastic multiple wells with gold nanoslits substrate were made using a thermal nanoimprint method. Adhesion cells in the wells were treated with doxorubicin for inducing cell death and compared with conventional colorimetric assay. The nanoslits method shows better respones of viability tests under low concentration and short interaction time due to its high surface sensitivies. The vinculin labelling indicates that the measured signals are in good agreement with the adhesion abilities of cells.
Terahertz electrodynamics in high electron-mobility transistors
Authors: Evangelisti F.
Published: September 2013

Plasmon current, charge oscillations, and associated electromagnetic fields in the THz range of a two-dimensional electron gas forming the channel of a high electron mobility transistor have been analysed by solving the full set of Euler, continuity, and Maxwell equations. Upon imposing boundary conditions, a finite-length channel behaves as a plasmonic cavity exhibiting strong resonance effects when the wavelength is commensurate with the channel length. It is shown that, if the relaxation time is not exceedingly short, the resonance effects should survive and be detectable. The presence of a metallic gate has a strong effect on the longitudinal waves, by changing both dispersion relation and propagation velocity for modes of wavelength larger than the gate-channel separation. Furthermore, gate and channel behave as a planar transmission line that readily transfers the gate-source signal to the gate-drain load impedance. Finally, it is suggested that the non-linear nature of the Euler equation can explain the observation of mixing and detection upon application of THz excitations to high-electron-mobility transistors devices.
Control of domain wall motion by interference of spin wave
Authors: Moon Kyoung-Woong , Sun Chun Byong , Kim Wondong , Hwang Chanyong
Published: September 2013

We propose a method to control the motions of magnetic domain walls using the interference phenomenon of the spin wave. It is found that when the distances between two neighboring walls are integer multiples of half wavelengths of the spin wave, the transmission coefficients of the spin wave are local maxima. This interference effect provides a new method for controlling the spin-wave-induced domain-wall motion, not only the speed of the domain wall motion but also its moving direction. In addition, tuning the distance of walls, we can find the direct relationship between the domain-wall velocity and the transmission coefficient, a crucial parameter of the spin-wave-induced domain-wall motions.