bluuebunny/crossref_metadata_2025 huggingface dataset:
Effectiveness of prevention programmes for obesity and chronic diseases among immigrants to developed countries – a systematic review
Authors: Renzaho Andre MN , Mellor David , Boulton Kelly , Swinburn Boyd
Published: September 2009

Objective

To determine whether interventions tailored specifically to particular immigrant groups from developing to developed countries decrease the risk of obesity and obesity-related diseases.

Design

Databases searched were MEDLINE (1966–September 2008), CINAHL (1982–September 2008) and PsychINFO (1960–September 2008), as well as Sociological Abstracts, PsychARTICLES, Science Direct, Web of Knowledge and Google Scholar. Studies were included if they were randomised control trials, ‘quasi-randomised’ trials or controlled before-and-after studies. Due to the heterogeneity of study characteristics only a narrative synthesis was undertaken, describing the target population, type and reported impact of the intervention and the effect size.

Results

Thirteen studies met the inclusion criteria. Ten out of thirteen (77 %) studies focused on diabetes, seven (70 %) of which showed significant improvement in addressing diabetes-related behaviours and glycaemic control. The effect on diabetes was greater in culturally tailored and facilitated interventions that encompassed multiple strategies. Six out of the thirteen studies (46 %) incorporated anthropometric data, physical activity and healthy eating as ways to minimise weight gain and diabetes-related outcomes. Of the six interventions that included anthropometric data, only two (33 %) reported improvement in BMI Z-scores, total skinfold thickness or proportion of body fat. Only one in three (33 %) of the studies that included cardiovascular risk factors reported improvement in diastolic blood pressure after adjusting for baseline characteristics. All studies, except four, were of poor quality (small sample size, poor internal consistency of scale, not controlling for baseline characteristics).

Conclusions

Due to the small number of studies included in the present review, the findings that culturally tailored and facilitated interventions produce better outcomes than generalised interventions, and that intervention content is more important than the duration or venue, require further investigation.
Geometry and evolution of low‐angle normal faults (LANF) within a Cenozoic high‐angle rift system, Thailand: Implications for sedimentology and the mechanisms of LANF development
Authors: Morley Chris K.
Published: September 2009

At least eight examples of large (5–35 km heave), low‐angle normal faults (LANFs, 20°–30° dip) occur in the Cenozoic rift basins of Thailand and laterally pass into high‐angle extensional fault systems. Three large‐displacement LANFs are found in late Oligocene–Miocene onshore rift basins (Suphan Buri, Phitsanulok, and Chiang Mai basins), they have (1) developed contemporaneous with, or after the onset of, high‐angle extension, (2) acted as paths for magma and associated fluids, and (3) impacted sedimentation patterns. Displacement on low‐angle faults appears to be episodic, marked by onset of lacustrine conditions followed by axial progradation of deltaic systems that infilled the lakes during periods of low or no displacement. The Chiang Mai LANF is a low‐angle (15°–25°), high‐displacement (15–35 km heave), ESE dipping LANF immediately east of the late early Miocene Doi Inthanon and Doi Suthep metamorphic core complexes. Early Cenozoic transpressional crustal thickening followed by the northward motion of India coupled with Burma relative to east Burma and Thailand (∼40–30 Ma) caused migmatization and gneiss dome uplift in the late Oligocene of the core complex region, followed by LANF activity. LANF displacement lasted 4–6 Ma during the early Miocene and possibly transported a late Oligocene–early Miocene high‐angle rift system 35 km east. Other LANFs in Thailand have lower displacements and no associated metamorphic core complexes. The three LANFs were initiated as low‐angle faults, not by isostatic rotation of high‐angle faults. The low‐angle dips appear to follow preexisting low‐angle fabrics (thrusts, shear zones, and other low‐angle ductile foliations) predominantly developed during Late Paleozoic and early Paleogene episodes of thrusting and folding.
Volcano‐tectonic implications of 3‐D velocity structures derived from joint active and passive source tomography of the island of Hawaii
Authors: Park Jaewoo , Morgan Julia K. , Zelt Colin A. , Okubo Paul G.
Published: September 2009

We present a velocity model of the onshore and offshore regions around the southern part of the island of Hawaii, including southern Mauna Kea, southeastern Hualalai, and the active volcanoes of Mauna Loa, and Kilauea, and Loihi seamount. The velocity model was inverted from about 200,000 first‐arrival traveltime picks of earthquakes and air gun shots recorded at the Hawaiian Volcano Observatory (HVO). Reconstructed volcanic structures of the island provide us with an improved understanding of the volcano‐tectonic evolution of Hawaiian volcanoes and their interactions. The summits and upper rift zones of the active volcanoes are characterized by high‐velocity materials, correlated with intrusive magma cumulates. These high‐velocity materials often do not extend the full lengths of the rift zones, suggesting that rift zone intrusions may be spatially limited. Seismicity tends to be localized seaward of the most active intrusive bodies. Low‐velocity materials beneath parts of the active rift zones of Kilauea and Mauna Loa suggest discontinuous rift zone intrusives, possibly due to the presence of a preexisting volcanic edifice, e.g., along Mauna Loa beneath Kilauea's southwest rift zone, or alternatively, removal of high‐velocity materials by large‐scale landsliding, e.g., along Mauna Loa's western flank. Both locations also show increased seismicity that may result from edifice interactions or reactivation of buried faults. New high‐velocity regions are recognized and suggest the presence of buried, and in some cases, previously unknown rift zones, within the northwest flank of Mauna Loa, and the south flanks of Mauna Loa, Hualalai, and Mauna Kea.
Microseismicity at the North Anatolian Fault in the Sea of Marmara offshore Istanbul, NW Turkey
Authors: Bulut Fatih , Bohnhoff Marco , Ellsworth William L. , Aktar Mustafa , Dresen Georg
Published: September 2009

The North Anatolian Fault Zone (NAFZ) below the Sea of Marmara forms a “seismic gap” where a major earthquake is expected to occur in the near future. This segment of the fault lies between the 1912 Ganos and 1999 İzmit ruptures and is the only NAFZ segment that has not ruptured since 1766. To monitor the microseismic activity at the main fault branch offshore of Istanbul below the Çınarcık Basin, a permanent seismic array (PIRES) was installed on the two outermost Prince Islands, Yassiada and Sivriada, at a few kilometers distance to the fault. In addition, a temporary network of ocean bottom seismometers was deployed throughout the Çınarcık Basin. Slowness vectors are determined combining waveform cross correlation and P wave polarization. We jointly invert azimuth and traveltime observations for hypocenter determination and apply a bootstrap resampling technique to quantify the location precision. We observe seismicity rates of 20 events per month for M < 2.5 along the basin. The spatial distribution of hypocenters suggests that the two major fault branches bounding the depocenter below the Çınarcık Basin merge to one single master fault below ∼17 km depth. On the basis of a cross‐correlation technique we group closely spaced earthquakes and determine composite focal mechanisms implementing recordings of surrounding permanent land stations. Fault plane solutions have a predominant right‐lateral strike‐slip mechanism, indicating that normal faulting along this part of the NAFZ plays a minor role. Toward the west we observe increasing components of thrust faulting. This supports the model of NW trending, dextral strike‐slip motion along the northern and main branch of the NAFZ below the eastern Sea of Marmara.
Compositional variations of the lunar crust: Results from radiative transfer modeling of central peak spectra
Authors: Cahill J. T. S. , Lucey P. G. , Wieczorek M. A.
Published: September 2009

We present model mineralogy of impact crater central peaks combined with crustal thickness and crater central peak depth of origin models to report multiple perspectives of lunar crustal composition with depth. Here we report the analyses of 55 impact crater central peaks and how their compositions directly relate to the lunar highlands sample suite. A radiative transfer model is used to analyze Clementine visible plus near‐infrared spectra to place compositional constraints on these central peak materials. Central peaks analyzed are dominantly magnesian‐ and plagioclase‐poor; strong compositional similarities to lunar Mg‐suite materials are evident. Relative to crustal thickness estimates, central peak mineralogy becomes more plagioclase‐rich as the crust thickens. Relative to the crust‐mantle boundary, the origin of peaks with dominantly mafic mineralogy are confined to the lower crust and primarily within the South‐Pole Aitken and Procellarum KREEP Terranes (PKT); additionally, central peaks with anorthositic mineralogy (>60 vol % plagioclase) are transported to the surface from all depths in the crustal column and confined to the Feldspathic Highlands Terrane (FHT). The discovery of mafic and magnesian materials, consistent with Mg‐suite rocks of the sample collection, in all lunar terranes suggests that the process and sources that give rise to these types of rocks is not unique to the PKT and not necessarily dependent on incompatible elements for formation. The identification of ferroan and magnesian anorthositic material near the crust‐mantle boundary of the FHT is also inconsistent with an increasing mafic/feldspar ratio and Mg' with depth in the crust.
Spatial and temporal dynamics of coupled groundwater and nitrogen fluxes through a streambed in an agricultural watershed
Authors: Kennedy Casey D. , Genereux David P. , Corbett D. Reide , Mitasova Helena
Published: September 2009

This paper presents results on the spatiotemporal dynamics of the coupled water flux (v) and nitrogen fluxes (fN = v[N], where [N] is the concentration of a dissolved N species) through a streambed in an agricultural watershed in North Carolina. Physical and chemical variables were measured at numerous points in the streambed of a 0.26‐km reach: hydraulic conductivity (K) and head gradient (J) and the concentrations of NO3− and other N species in streambed groundwater, from which water flux (v = KJ) and N fluxes (e.g., fNO3 = v[NO3−]) through the streambed were computed, mapped, and integrated in space. The result was a novel set of streambed maps of the linked variables (K, J, v, and N concentrations and fluxes), showing their spatial variability and how it changed over a year (on the basis of seven bimonthly sets of maps). Mean fNO3 during the study year was 154 mmol m−2 d−1; this NO3− flux, together with that of dissolved organic nitrogen (fDON = 17 mmol m−2 d−1), accounted for >99% of the total dissolved N flux through the streambed. Repeat measurements at the same locations on the streambed show significant temporal variability in fNO3, controlled largely by changes in v rather than changes in [NO3−]. One of the clearest and most persistent aspects of spatial variability was lateral variability across the channel from bank to bank. K and v values were greater in the center of the channel; this distribution of K (ultimately a reflection of sediment dynamics in the channel) apparently focuses groundwater discharge toward the center of the channel. The opposite pattern (low values in the center) was found for J, [NO3−], and (to a lesser extent) fNO3. Overall, fNO3 was characterized by localized zones of high and low values that changed in size and shape over time but remained in basically the same locations (the same was true of K, J, and [NO3−], though less so for v), with 70% of NO3− flux occurring through about 38% of the streambed area. Lateral distributions of the physical hydrologic attributes (K, J, and v) were highly symmetrical across the channel, while those of [NO3−] and fNO3 showed higher values on the left than on the right, likely a reflection of different N use on opposite sides of the stream. The streambed‐based approach taken here offers insights concerning the spatial and temporal dynamics of linked water and N fluxes through a streambed and their controls.
Bayesian model averaging for groundwater head prediction and uncertainty analysis using multimodel and multimethod
Authors: Li Xiaobao , Tsai Frank T.‐C.
Published: September 2009

This study introduces a Bayesian model averaging (BMA) method that incorporates multiple groundwater models and multiple hydraulic conductivity estimation methods to predict groundwater heads and evaluate prediction uncertainty. BMA is able to distinguish prediction uncertainty arising from individual models, between models, and between methods. Moreover, BMA is able to identify unfavorable models even though they may present small prediction uncertainty. Uncertainty propagation, from model parameter uncertainty to model prediction uncertainty, can also be studied through BMA. This study adopts a variance window to obtain reasonable BMA weights for the best models, which are usually exaggerated by Occam's window. Results from a synthetic case study show that BMA with the variance window can provide better head prediction than individual models, or at least can obtain better predictions close to the best model. The BMA was applied to predicting groundwater heads in the “1500‐foot” sand of the Baton Rouge area in Louisiana. Head prediction uncertainty was assessed by the BMA prediction variance. BMA confirms that large head prediction uncertainty occurs at areas lacking head observations and hydraulic conductivity measurements. Further study in these areas is necessary to reduce head prediction uncertainty.
Variability in tornado frequency associated with U.S. landfalling tropical cyclones
Authors: Belanger James I. , Curry Judith A. , Hoyos Carlos D.
Published: September 2009

A statistical model for tornado frequency from Gulf of Mexico landfalling tropical cyclones (TCs) is developed using TC size, intensity, recurvature, and mid‐level specific humidity data. New datasets are assembled for tornado frequency and for TC size at landfall as measured by the radius of outer closed isobar and distance of tornado from the TC center. Owing to systematic undercounting of tornadoes, the model is used to reconstruct the TC tornado climatology back to 1948, and further back to 1920 using a modified model that does not include mid‐level specific humidity. Relative to the previous active period for Gulf TC landfalls of 1948–1964, the active period since 1995 has seen a statistically significant increase (95% level) in median TC tornadoes and in the frequency of large TC tornado outbreaks. These changes are linked to an increase in the median size and frequency of large Gulf landfalling TCs.
In vivo Assessment of Macrophage CNS Infiltration during Disruption of the Blood–Brain Barrier with Focused Ultrasound: A Magnetic Resonance Imaging Study
Authors: Liu Hao-Li , Wai Yau-Yau , Hsu Po-Hong , Lyu Lee-Ang , Wu Jia-Shin , Shen Chia-Rui , Chen Jin-Chung , Yen Tzu-Chen , Wang Jiun-Jie
Published: September 2009

Focused ultrasound has been discovered to locally and reversibly increase permeability of the blood–brain barrier (BBB). However, inappropriate sonication of the BBB may cause complications, such as hemorrhage and brain tissue damage. Tissue damage may be controlled by selecting optimal sonication parameters. In this study, we sought to investigate the feasibility of labeling cells with superparamagnetic iron oxide particles to assess the inflammatory response during focused-ultrasound-induced BBB opening. We show that infiltration of phagocytes does not occur using optimal parameters of sonication. Taken together, the results of our study support the usefulness and safety of focused-ultrasound-induced BBB opening for enhancing drug delivery to the brain. These findings may have implications for the optimization of sonication parameters.
Anomalous Venous Blood Flow and Iron Deposition in Multiple Sclerosis
Authors: Singh Ajay Vikram , Zamboni Paolo
Published: September 2009

Multiple sclerosis (MS) is primarily an autoimmune disorder of unknown origin. This review focuses iron overload and oxidative stress as surrounding cause that leads to immunomodulation in chronic MS. Iron overload has been demonstrated in MS lesions, as a feature common with other neurodegenerative disorders. However, the recent description of chronic cerebrospinal venous insufficiency (CCSVI) associated to MS, with significant anomalies in cerebral venous outflow hemodynamics, permit to propose a parallel with chronic venous disorders (CVDs) in the mechanism of iron deposition. Abnormal cerebral venous reflux is peculiar to MS, and was not found in a miscellaneous of patients affected by other neurodegenerative disorders characterized by iron stores, such as Parkinson's, Alzheimer's, amyotrophic lateral sclerosis. Several recently published studies support the hypothesis that MS progresses along the venous vasculature. The peculiarity of CCSVI-related cerebral venous blood flow disturbances, together with the histology of the perivenous spaces and recent findings from advanced magnetic resonance imaging techniques, support the hypothesis that iron deposits in MS are a consequence of altered cerebral venous return and chronic insufficient venous drainage.
Spontaneous Intracerebral Hemorrhage during Acute and Chronic Hypertension in Mice
Authors: Wakisaka Yoshinobu , Chu Yi , Miller Jordan D , Rosenberg Gary A , Heistad Donald D
Published: September 2009

Oxidative stress and matrix metalloproteinases (MMPs) contribute to hemorrhagic transformation after ischemic stroke and brain injury after intracerebral hemorrhage (ICH). The goal of this study was to develop a new model of spontaneous ICH, based on the hypothesis that acute, superimposed on chronic, hypertension produces ICH. We hypothesized that increases in angiotensin II (AngII)-mediated oxidative stress and activation of MMPs are associated with, and may precede, spontaneous ICH during hypertension. In C57BL/6 mice, chronic hypertension was produced with AngII infusion and an inhibitor of nitric oxide synthase. During chronic hypertension, mice with acute hypertension from injections of AngII developed ICH. Oxidative stress and MMP levels increased in the brain even before developing ICH. Active MMPs colocalized with a marker of oxidative stress, especially on cerebral vessels that appeared to lead toward regions with ICH. Incidence of ICH and levels of oxidative stress and MMP-9 were greater in mice with acute hypertension produced by AngII than by norepinephrine. In summary, we have developed an experimental model of ICH during hypertension that may facilitate studies in genetically altered mice. We speculate that acute hypertension, especially when induced by AngII, may be critical in spontaneous ICH during chronic hypertension, possibly through oxidative stress and MMP-9.
Fenofibrate Improves Cerebral Blood Flow after Middle Cerebral Artery Occlusion in Mice
Authors: Guo Qingmin , Wang Guangming , Namura Shobu
Published: September 2009

Fibrates, one group of peroxisome proliferator-activated receptor (PPAR) activators, are lipid lowering drugs. Fibrates have been shown to attenuate brain tissue injury after focal cerebral ischemia. In this study, we investigated the impact of fenofibrate on cerebral blood flow (CBF) in male wild type and PPARα-null mice. Animals were treated for 7 days with fenofibrate and subjected to 2 h of filamentous middle cerebral artery occlusion and reperfusion under isoflurane anesthesia. Cortical surface CBF was measured by laser speckle imaging. Regional CBF (rCBF) in nonischemic animals was measured by 14C-iodoantipyrine autoradiography. Fenofibrate did not affect rCBF and mean arterial blood pressure in nonischemic animals. In ischemic animals, laser speckle imaging showed delayed expansions of ischemic area, which was attenuated by fenofibrate. Fenofibrate also enhanced CBF recovery after reperfusion. However, such effects of fenofibrate on CBF in the ischemic brain were not observed in PPARα-null mice. These findings show that fenofibrate improves CBF in the ischemic hemisphere. Moreover, fenofibrate requires PPARα expression for the cerebrovascular protective effects in the ischemic brain.
MUEGANO: A divide and conquer algorithm to overcome memory limitations when assembling shotgun projects
Authors: Martinez Octavio , Fernandez-Cortes Araceli
Published: September 2009

When assembling a large quantity of reads in a genomic shotgun project a serious limitation is the amount of random access memory (RAM) of the computers used in the project. This arises because all assembling programs must look at all the overlaps between reads at the same time, using RAM in order to construct contigs, and the memory of the computer can be filled up during this step, causing the abortion of the assembling process.Here we propose an algorithm that is capable of overcoming any memory limitation by using redundancy of processing and thus producing an increase in computing time but overcoming the memory limitation.The proposed algorithm consists in dividing the reads in a set of groups which size is half the maximum capability in memory of the computer used and performing assembling for all the possible combination pairs of such groups. After eliminating the redundancy of the set of contigs obtained in the previous step, the process is iterated until a set of contigs of manageable size is obtained such that the set can be handled by the assembler in a final step.Each step of the procedure increases the time of computing from k to approximately k + k(k-1)/2, but in many practical cases only one step is needed to finish the assembling process. The procedure is suitable for any kind of assembler and was successfully applied to the assembly of a very large set of reads from the maize genome.
Effects of silylation on fracture and mechanical properties of mesoporous silica films interfaced with copper
Authors: Gandhi D. D. , Singh B. , Singh A. P. , Moore R. , Simonyi E. , Lane M. W. , Ramanath G.
Published: September 2009

Mesoporous silica (MPS) films are attractive for isolating Cu wiring in nanodevices but are susceptible to pore wall collapse and water and metal uptake. Pore-sealing and chemical passivation with molecular surfactants are potential solutions that could address these challenges. Here, we show that silylated MPS films capped with a Cu overlayer fracture near the Cu/MPS interface at a distance that correlates with the Cu penetration depth into MPS. Pristine MPS films fracture farther from the MPS/Cu interface than silylated MPS, where silylation-induced pore passivation hinders Cu penetration. Silylation also lowers the tensile stress and the fracture toughness of MPS films, but the relative extent of the decreases in these properties decreases the overall driving force for cracking. Such effects of molecular passivation on metal penetration, film stress, and fracture toughness and pathways are important for engineering stable porous dielectrics for nanodevice wiring structures.
Wakefield driven by Gaussian (1,0) mode laser pulse and laser-plasma electron acceleration
Authors: Che H. O. , Kong Q. , Mao Q. Q. , Wang P. X. , Ho Y. K. , Kawata S.
Published: September 2009

An ultraintense Gaussian (1,0) mode pulsed laser applied to laser-plasma electron acceleration is investigated based on 2.5-dimensional particle-in-cell simulation (PIC). It has been found that Gaussian (1,0) mode laser pulse may blow out plasma electrons and form two symmetrical electron cavities with an electron wall between them. This electron wall separates two twisting bunches of transverse injected electrons and lets each of them be accelerated in one cavity, respectively. At the front of the wall, a bunch of reflux electrons with a magnetic field contributes to the electron self-bunching effect. This mechanism may generate two symmetrical, high-density, and monoenergetic electron beams with small transverse emittances.
Investigation of the additive induced doping effects in gelcast soft lead zirconate titanate ceramics
Authors: Guo Dong , Cai Kai , Li Longtu , Gui Zhilun
Published: September 2009

Due to the high sensitivity of the electrical properties of electronic ceramics to various factors, knowledge about the possible influence of the processing procedure on their electrical performance is critical for applying a new technique to the fabrication of the materials. In this study, various electrical parameters, complex impedance spectra, ferroelectric hysteresis loops, and microstructures of soft lead zirconate titanate (PZT) ceramics formed by the gelcasting technique from suspensions with various dispersants were investigated in comparison with those of the conventional dry pressed ones. We found that the sodium ion, which is the main cation in many commercial surfactants, exhibited obvious hard doping effects; thus causing deteriorated performance of the gelcast PZT ceramics. While a certain impurity ion introduced by a dispersant was also found to induce soft doping characteristics and improve the electrical performance of the materials. The results suggest that the doping effects of the metal ions or impurities introduced by the dispersants, or other additives, should be generally considered for applying a wet processing technique to forming multicomponent electronic ceramics.
Translational cooling versus vibrational quenching in ultracold OH−–Rb collisions: A quantum assessment
Authors: Tacconi M. , Gianturco F. A.
Published: September 2009

A new three-dimensional potential energy surface (PES), which describes the interaction between the OH−(X Σ1+) anionic molecule and the Rb(S2) atomic gas has been obtained by using a highly correlated ab initio model of the electronic structure and a large atomic basis set supplemented with a set of midbond Gaussian functions. This accurate PES is being employed to evaluate the OH−(X Σ1+) vibrational quenching efficiency induced by collisions with Rb(S2) at low and ultralow energies. Calculations employ the coupled-channel ansatz to describe the nuclear quantum dynamics and finally show a very marked dependence of the inelastic cross sections and rates, at vanishing collision energies, on the initial vibrational energy content of the partner molecules. The present findings allow us to make specific suggestions on the likely outcomes from energy interplay between the title species within a mixed MOT/Paul Trap environment.
Resolving the coverage puzzle of the Pb/Si(111)−7×3 phase
Authors: Švec Martin , Cháb Vladimír , Tringides Michael C.
Published: September 2009

The dense Pb/Si(111)-α−3×3 has been extensively studied over the last 20 years with scanning tunneling microscopy (STM) and surface diffraction to determine its structure and its phase transformations with temperature T and coverage θ. Two apparently incompatible models have been proposed for the structure and have been debated in the literature. One model was based on a coverage assignment θ=1 ML. The other model was based on assigning coverage in the range 1.2 ML<θ<4/3 ML. The current experiments show that there are two different 7×3 phases with the same unit cell symmetry but different stoichiometry. This hopefully answers the debated question.
Ionic velocities in an ionic liquid under high electric fields using all-atom and coarse-grained force field molecular dynamics
Authors: Daily John W. , Micci Michael M.
Published: September 2009

Molecular dynamics has been used to estimate ionic velocities and electrical conductivity in the ionic liquid 1-ethyl-3-methylimidazolium/tetraflouroborate (EMIM-BF4). Both an all-atom and coarse grained force fields were explored. The simulations were carried out at high electric fields where one might expect the Wien effect to become important in conventional electrolytes and that effect is observed. While the original Wilson theory used to explain the Wien effect in conventional electrolytes does not work well for ionic liquids, a minor modification of the theory allowed it to be used to qualitatively describe the data. The two coarse-graining methods were noisier as expected, but result in a significant savings in computational cost.
Methods and analysis of processing signals of incremental optoelectronic transducer
Authors: Szcześniak Adam , Szcześniak Zbigniew
Published: September 2009

This article is a presentation of designed methods which interpolate signals from the optoelectronic transducer. This enables a way to distinguish the motion direction of the optoelectronic transducer and also to increase its accuracy. In this article methods based on logic functions, logic functions and RC circuits, phase processing were analyzed. In methods which are based on processing logic functions of transducer’s signals there is a possibility of two times and four times increase in the transducer glass scale. The presented method of generating and processing sine signals with 18° of the shift enables the reception of square signals with five times higher frequency compared to the basic signals. This method is universal and it can be used to the different scale of frequency multiplication of the optoelectronic transducer. The simulations of the methods were performed by using the MATLAB-SIMULINK software.
Electrochemical growth and resistive switching of flat-surfaced and (111)-oriented Cu2O films
Authors: Kang Sung-Oong , Hong Sahwan , Choi Jinsik , Kim Jin-Soo , Hwang Inrok , Byun Ik-Su , Yun Kyu-Sik , Park Bae Ho
Published: September 2009

Flat-surfaced and fully (111)-oriented Cu2O films were grown through a chelate-assisted electrochemical approach. Based on key roles of chelating agent, the flat surface of films controlled over the columnar-grained growth was obtainable with a root-mean-square roughness value below 3 nm. Cu2O films treated by a rapid-thermal-annealing process at 200 °C exhibited unipolar switching I-V characteristics, presenting the bistable resistance states with a high resistance ratio (Roff/Ron) over 3 orders of magnitude and considerably stable switching properties within 100 switching cycles.
Precise determination of the pressure distortion coefficient of new controlled-clearance piston-cylinders based on the Heydemann–Welch model
Authors: Kajikawa Hiroaki , Ide Kazunori , Kobata Tokihiko
Published: September 2009

A new controlled-clearance (CC) pressure balance has been developed with the aim of improving hydraulic pressure standards up to pressures of 1 GPa. The pressure balance is equipped with a weight-loading unit that can load/unload selected weights automatically and a CC piston-cylinder that is designed for the jacket pressure to be applied independently. In this paper, the effective area Ae of two kinds of the CC piston-cylinders for pressures of 200 and 500 MPa was examined based on the Heydemann–Welch model. The two parameters in the model, the jacket pressure coefficient and the zero clearance jacket pressure, were precisely determined by the characterization experiments, after which the pressure dependence of Ae and its uncertainty were estimated. The uncertainty due to the pressure dependence of Ae for the 500 MPa CC piston-cylinder was less than 7.5×10−8 MPa−1. To confirm the consistency of the estimations, the results of the two CC piston-cylinders were compared through a free-deformation (FD) piston-cylinder; the two estimations were in agreement with each other. Moreover, it was shown that the extent of nonlinearity in the pressure dependence of Ae of the FD piston-cylinder can be evaluated by calibration against the CC piston-cylinder.
Simulated-tempering replica-exchange method for the multidimensional version
Authors: Mitsutake Ayori
Published: September 2009

In this article, the general formulation of the multidimensional simulated-tempering replica-exchange method is described. In previous works, the one-dimensional replica-exchange simulated-tempering and simulated-tempering replica-exchange methods were developed. For the former method, the weight factor of the one-dimensional simulated tempering is determined by a short replica-exchange simulation and multiple-histogram reweighing techniques. For the latter method, the production run is a replica-exchange simulation with a few replicas not in the canonical ensembles but in the simulated-tempering ensembles which cover wide ranges of temperature. Recently, the general formulation of the multidimensional replica-exchange simulated tempering was presented. In this article, the extension of the simulated-tempering replica-exchange method for the multidimensional version is given. As an example of applications of the algorithm, a two-dimensional replica-exchange simulation and two simulated-tempering replica-exchange simulations have been performed. Here, an α-helical peptide system with a model solvent has been used for the applications.
Study of electrical performance and stability of solution-processed n-channel organic field-effect transistors
Authors: Tiwari Shree Prakash , Zhang Xiao-Hong , Potscavage William J. , Kippelen Bernard
Published: September 2009

Solution processed n-channel organic field-effect transistors based on [6,6]-phenyl C61 butyric acid methyl ester with high mobility and low contact resistance are reported. Ca, Au, or Ca capped with Au (Ca/Au) was used as the top source/drain electrodes. The devices with Ca electrodes exhibit excellent n-channel behavior with electron mobility values of 0.12 cm2/V s, low threshold voltages (∼2.2 V), high current on/off ratios (105–106) and subthreshold slopes of 0.7 V/decade. By varying the channel lengths (25–200 μm) in devices with different metal/semiconductor interfaces, the effect of channel length scaling on mobility is studied and the contact resistance is extracted. The width-normalized contact resistance (RCW) for Au (12 kΩ cm) is high in comparison to Ca (7.2 kΩ cm) or Ca/Au (7.5 kΩ cm) electrodes at low gate voltage (VGS=10 V). However, in the strong accumulation regime at high gate voltage (VGS=30 V), its value is nearly independent of the choice of metal electrodes and in a range of 2.2–2.6 kΩ cm. These devices show stable electrical behavior under multiple scans and low threshold voltage instability under electrical bias stress (VDS=VGS=30 V, 1 h) in N2 atmosphere.
Ab initio studies of electronic properties of bare GaN(0001) surface
Authors: Kempisty Paweł , Krukowski Stanisław , Strąk Paweł , Sakowski Konrad
Published: September 2009

Laplace correction was used for solutions of Poisson equation in density functional theory (DFT) slab simulations of GaN (0001) surface. In accordance to the scenario of Meyer and Marx [Phys. Rev. B 67, 35403 (2003)], the electric field, emerging within the slab, is determined by the condition that Fermi energy is equal to the energies of valence band maximum and conduction band minimum at both sides of the slab. In contrast to their predictions that the field is identical for different slab thicknesses, it was found from DFT calculations that the electric potential difference between two sides of the slab is kept constant. Therefore, the energy of the slab does not diverge for large slab thickness. It was also found that, in most cases, the field in the slab is determined by pinning by surface states. Thus the change in opposite side slab termination, both by different types of atoms and by their location, can be used to change electric field in the slab, creating a tool that can be used to simulate the change in surface properties due to doping of the bulk. It was shown that, depending on the electric field, the energy of surface states changes in the way different from the band states. This change could be large, comparable to the bandgap. Despite the fact that the Fermi energy can be pinned to surface states, it may change its energy with respect to valence band and conduction band as a function of the doping of bulk semiconductor. These results are in agreement with the experimental data showing variation in Fermi energy at the GaN (0001) surface in function of the doping in the bulk. It was also shown using the electron density and potential profiles that ten Ga–N atomic layers are necessary to achieve small quantum overlap of the surface states of both sides of the slab, which is required for high precision simulations of the surface.
Probabilistic sensitivity analysis of biochemical reaction systems
Authors: Zhang Hong-Xuan , Dempsey William P. , Goutsias John
Published: September 2009

Sensitivity analysis is an indispensable tool for studying the robustness and fragility properties of biochemical reaction systems as well as for designing optimal approaches for selective perturbation and intervention. Deterministic sensitivity analysis techniques, using derivatives of the system response, have been extensively used in the literature. However, these techniques suffer from several drawbacks, which must be carefully considered before using them in problems of systems biology. We develop here a probabilistic approach to sensitivity analysis of biochemical reaction systems. The proposed technique employs a biophysically derived model for parameter fluctuations and, by using a recently suggested variance-based approach to sensitivity analysis [Saltelli et al., Chem. Rev. (Washington, D.C.) 105, 2811 (2005)], it leads to a powerful sensitivity analysis methodology for biochemical reaction systems. The approach presented in this paper addresses many problems associated with derivative-based sensitivity analysis techniques. Most importantly, it produces thermodynamically consistent sensitivity analysis results, can easily accommodate appreciable parameter variations, and allows for systematic investigation of high-order interaction effects. By employing a computational model of the mitogen-activated protein kinase signaling cascade, we demonstrate that our approach is well suited for sensitivity analysis of biochemical reaction systems and can produce a wealth of information about the sensitivity properties of such systems. The price to be paid, however, is a substantial increase in computational complexity over derivative-based techniques, which must be effectively addressed in order to make the proposed approach to sensitivity analysis more practical.
Slow light in narrow paraffin-coated vapor cells
Authors: Klein M. , Hohensee M. , Nemiroski A. , Xiao Y. , Phillips D. F. , Walsworth R. L.
Published: September 2009

Alkali vapor cells with antirelaxation coated walls can have long atomic coherence times. However, using such coated cells in the hyperfine configuration for electromagnetically induced transparency (EIT) requires longitudinal atomic motion to be confined to less than the hyperfine wavelength. We employed a narrow (1 mm) coated cell geometry to study hyperfine EIT and slow and stored light in warm R87b vapor, with results comparable to those in buffer gas cells and showing the promise of such cells for several applications.
Nonuniform doping distribution along silicon nanowires measured by Kelvin probe force microscopy and scanning photocurrent microscopy
Authors: Koren E. , Rosenwaks Y. , Allen J. E. , Hemesath E. R. , Lauhon L. J.
Published: September 2009

We use Kelvin probe force microscopy and scanning photocurrent microscopy to measure the doping distribution along single phosphorous-doped silicon nanowire grown by the vapor-liquid-solid method. A nonlinear potential drop along biased silicon nanowires is detected both by measuring the surface potential directly via Kelvin probe force microscopy and by integrating the photocurrent measured by scanning photocurrent microscopy. These variations in the potential and field are further analyzed to extract the longitudinal dopant distribution along an individual silicon nanowire. The results show a very good agreement between the two methods to quantitatively detect potential, field, and doping variations within doped silicon nanowires.
The reduction of Eu3+ to Eu2+ in BaMgAl10O17:Eu and the photoluminescence properties of BaMgAl10O17:Eu2+ phosphor
Authors: Liu Bitao , Wang Yuhua , Zhou Jun , Zhang Feng , Wang Zhaofeng
Published: September 2009

The variations in emission intensities of AlO4-tetrahedron-containing compound BaMgAl10O17:Eu (BAM) phosphor prepared in different atmospheres is discussed in view of the structure of host compounds. A reduction phenomenon of Eu3+→Eu2+ was observed by emission and excitation spectra measurement in BAM for the first time. This reduction was explained by a charge compensation mechanism and the photoluminescence properties were discussed. By comparison, it was found that Eu2+ ions occupy three different lattice sites by substitution for Ba2+ ions in BaMgAl10O17:Eu2+. BaMgAl10O17:Eu2+ phosphors exhibited more excellent thermal stability when Eu2+ ions occupied more Eu (1) sites, and gave a dominating contribution for the photoluminescence when Eu2+ ions occupied Eu (2) sites.
Polaron relaxation associated with the localized oxygen vacancies in Ba0.85Sr0.15TiO3 ceramics at high temperatures
Authors: Li Zhuo , Fan Huiqing
Published: September 2009

The temperature and frequency dependences of dielectric properties of barium strontium titanate [Ba0.85Sr0.15TiO3 (BST15)] ceramics have been investigated. The dielectric relaxation behavior above 180 °C was observed in BST15 ceramics with broad dielectric peaks. The contribution of dc conduction and universal dielectric response to the relaxation has been studied. In contrast to typical ion conductor such as La2Mo2O9, the extent of dielectric dispersion shows the similar temperature dependence characteristic. Polaron theory indicates that the relaxation in BST15 ceramics at high temperatures is associated with the hopping localized oxygen vacancies.
Investigation of biferroic properties in La0.6Sr0.4MnO3/0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 epitaxial bilayered heterostructures
Authors: Chaudhuri Ayan Roy , Krupanidhi S. B. , Mandal P. , Sundaresan A.
Published: September 2009

Epitaxial bilayered thin films consisting of La0.6Sr0.4MnO3 (LSMO) and 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 (PMN-PT) layers of relatively different thicknesses were fabricated on LaNiO3 coated LaAlO3 (100) single crystal substrates by pulsed laser ablation technique. The crystallinity, ferroelectric, ferromagnetic, and magnetodielectric properties have been studied for all the bilayered heterostructures. Their microstructural analysis suggested possible Stranski–Krastanov type of growth mechanism in the present case. Ferroelectric and ferromagnetic characteristics of these bilayered heterostructures over a wide range of temperatures confirmed their biferroic nature. The magnetization and ferroelectric polarization of the bilayered heterostructures were enhanced with increasing PMN-PT layer thickness owing to the effect of lattice strain. In addition, evolution of the ferroelectric and ferromagnetic properties of these heterostructures with changing thicknesses of the PMN-PT and LSMO layers indicated possible influence of several interfacial effects such as space charge, depolarization field, domain wall pinning, and spin disorder on the observed properties. Dielectric properties of these heterostructures studied over a wide range of temperatures under different magnetic field strengths suggested a possible role of elastic strain mediated magnetoelectric coupling behind the observed magnetodielectric effect in addition to the influence of rearrangement of the interfacial charge carriers under an applied magnetic field.
A study of hard:soft layer ratios and angular switching in exchange coupled media
Authors: Baker A. , Billard M. , Brown K. , Goadsby A. , Green S. , Howard C. , Kodippili S. , Newton A. , Ning X. , Stead M. , Vallance L. , Zang L. , Allwood D. A. , Bryan M. T. , Dean J.
Published: September 2009

We have performed micromagnetic simulations to investigate the magnetic behavior of exchange spring grains for hard disk recording applications. The thickness ratio between magnetically hard and soft layers was varied while the soft layer anisotropy was altered to maintain a suitable energy barrier between opposite magnetization states. The minimum required magnetic field for switching a grain and the corresponding field angle were both significantly reduced in exchange spring material compared with single-phase grains. This could lead to reduced cross-track write errors in hard drive systems and assist the development of magnetic multilayer recording technologies.
Determination of second-order elastic constants of cyclotetramethylene tetranitramine (β-HMX) using impulsive stimulated thermal scattering
Authors: Sun B. , Winey J. M. , Gupta Y. M. , Hooks D. E.
Published: September 2009

The second-order elastic constants for cyclotetramethylene tetranitramine (β-HMX) single crystals were determined using the impulsive stimulated thermal scattering (ISTS) method. Despite the low symmetry of these crystals, the complete set of 13 elastic constants were determined accurately from acoustic velocity measurements using samples cut parallel to three different crystal planes. Our acoustic velocities are consistent with the limited sound speed data available from ultrasonic measurements. However, significant differences are observed between the elastic constants determined from our experiments and those obtained previously using Brillouin scattering. Our results demonstrate the usefulness and efficiency of the ISTS method for determining the full set of elastic constants of low-symmetry molecular crystals, including energetic crystals.
Laser pulse guiding and electron acceleration in the ablative capillary discharge plasma
Authors: Kameshima T. , Kotaki H. , Kando M. , Daito I. , Kawase K. , Fukuda Y. , Chen L. M. , Homma T. , Kondo S. , Esirkepov T. Zh. , Bobrova N. A. , Sasorov P. V. , Bulanov S. V.
Published: September 2009

The results of experiments are presented for the laser electron acceleration in the ablative capillary discharge plasma. The plasma channel is formed by the discharge inside the ablative capillary. The intense short laser pulse is guided over a 4 cm length. The generated relativistic electrons show both the quasimonoenergetic and quasi-Maxwellian energy spectra, depending on laser and plasma parameters. The analysis of the inner walls of the capillaries that underwent several tens of shots shows that the wall deformation and blistering resulted from the discharge and laser pulse effects.
Protein dynamics from single-molecule fluorescence intensity correlation functions
Authors: Gopich Irina V. , Nettels Daniel , Schuler Benjamin , Szabo Attila
Published: September 2009

Fluorescence intensity correlation functions contain information about photophysical and conformational dynamics. We propose and implement a simple procedure to analyze such functions measured in the presence of resonance energy transfer. When there is a separation of time scales and the conformational dynamics is modeled as diffusion in the potential of mean force along the interdye distance, we obtain an analytic expression for the conformational correlation time. This can be used to find the diffusion coefficient describing conformational fluctuations given the photon count rate and equilibrium distribution.