bluuebunny/crossref_metadata_2025 huggingface dataset:
PRE-MARKET CLINICAL EVALUATIONS OF INNOVATIVE HIGH-RISK MEDICAL DEVICES IN EUROPE
Authors: Hulstaert Frank , Neyt Mattias , Vinck Imgard , Stordeur Sabine , Huić Mirjana , Sauerland Stefan , Kuijpers Marja R. , Abrishami Payam , Vondeling Hindrik , Flamion Bruno , Garattini Silvio , Pavlovic Mira , van Brabandt Hans
Published: September 2012

Objectives:High-quality clinical evidence is most often lacking when novel high-risk devices enter the European market. At the same time, a randomized controlled trial (RCT) is often initiated as a requirement for obtaining market access in the US. Should coverage in Europe be postponed until RCT data are available? We studied the premarket clinical evaluation of innovative high-risk medical devices in Europe compared with the US, and with medicines, where appropriate.

Methods:The literature and regulatory documents were checked. Representatives from industry, Competent Authorities, Notified Bodies, Ethics Committees, and HTA agencies were consulted. We also discuss patient safety and the transparency of information.

Results:In contrast to the US, there is no requirement in Europe to demonstrate the clinical efficacy of high-risk devices in the premarket phase. Patients in Europe can thus have earlier access to a potentially lifesaving device, but at the risk of insufficiently documented efficacy and safety. Variations in the stringency of clinical reviews, both at the level of Notified Bodies and Competent Authorities, do not guarantee patient safety. We tried to document the design of premarket trials in Europe and number of patients exposed, but failed as this information is not made public. Furthermore, the Helsinki Declaration is not followed with respect to the registration and publication of premarket trials.

Conclusions:For innovative high-risk devices, new EU legislation should require the premarket demonstration of clinical efficacy and safety, using an RCT if possible, and a transparent clinical review, preferably centralized.
STRENGTHENING THE HEALTH SYSTEM TO ENHANCE MENTAL HEALTH IN ZAMBIA: A POLICY BRIEF
Authors: Mwape Lonia , Mweemba Prudencia , Kasonde Joseph
Published: September 2012

Background: Mental illness constitutes a large proportion of the burden of disease in Zambia. Yet mental health services at the primary care level are either provided in a fragmented manner or are lacking altogether.

Methods: A literature review focused on terms including mental health and primary care and strategic options were analyzed.

Results: From the analysis, two options were considered for integrating mental health into primary health care. An incremental option would start with a pilot project introducing mental health services into primary care with a well-designed evaluation before scaling up. One key advantage of this option is that it is possible to make improvements in the plan, if needed, before scaling up. A comprehensive option would entail introducing mental health services into primary care in all nine provinces of Zambia. In this option, scaling up could occur more rapidly than an incremental approach.

Conclusions: Strategies to implement either option must address several barriers, including insufficient funding for mental health services, inadequate mental health indicators, lack of general public awareness of and social stigma attached to mental illnesses and mental health care not being perceived as cost-effective or affordable.
HEALTH TECHNOLOGY REASSESSMENT: SCOPE, METHODOLOGY, & LANGUAGE
Authors: Noseworthy Tom , Clement Fiona
Published: September 2012

Health systems are challenged continuously to provide the highest quality universal health care within their means. While for 30 years, health technology assessment (HTA) has contributed to the process of evidence-informed decision making and the managed entry of new technologies, its remit has not expanded to include assessment of technologies currently in use, as a means of managing their use and potentially their exit. We propose that health technology reassessment (HTR) become standard practice, an integral part of all health technology assessment agencies, and that we develop standardized models and methodologies for reassessment drawing from what we have learned from HTA.
Cryoprotective effects of low-density lipoproteins, trehalose and soybean lecithin on murine spermatogonial stem cells
Authors: Wang Peng , Li Ying , Hu Xiao-chen , Cai Xiao-Li , Hou Li-Peng , Wang Yan-Feng , Hu Jian-Hong , Li Qing-Wang , Suo Li-Juan , Fan Zhi-Guo , Zhang Bo
Published: September 2012

Spermatogonial stem cells (SSCs) have the ability to self-renew and offer a pathway for genetic engineering of the male germ line. Cryopreservation of SSCs has potential value for the treatment of male infertility, spermatogonial transplantation, and so on. In order to investigate the cryopreservation effects of different cryoprotectants on murine SSCs, 0.2 M of low-density lipoproteins (LDL), trehalose and soybean lecithin were added to the cryoprotective medium, respectively, and the murine SSCs were frozen at −80°C or −196°C. The results indicated that the optimal recovery rates of murine SSCs in the cryoprotective medium supplemented with LDL, trehalose and soybean lecithin were 92.53, 76.35 and 75.48% at −80°C, respectively. Compared with freezing at −196°C, the optimum temperature for improvement of recovery rates of frozen murine SSCs, cryopreservation in three different cryoprotectants at −80°C, were 17.11, 6.68 and 10.44% respectively. The recovery rates of murine SSCs in the cryoprotective medium supplemented with 0.2 M LDL were significantly higher than that of other cryoprotectants (P < 0.05). Moreover, the recovery rates were demonstrated to be greater at −80°C compared with at −196°C (P < 0.05). In conclusion, 0.2 M of LDL could significantly protect murine SSCs at −80°C. In the freezing–thawing process, LDL is responsible for the cryopreservation of murine SSCs because it can form a protective film at the surface of membranes. However, more research is needed to evaluate and understand the precise role of LDL during the freezing–thawing of SSCs.
Orthographic influences on division of labor in learning to read Chinese and English: Insights from computational modeling
Authors: YANG JIANFENG , SHU HUA , McCANDLISS BRUCE D. , ZEVIN JASON D.
Published: September 2012

Learning to read in any language requires learning to map among print, sound and meaning. Writing systems differ in a number of factors that influence both the ease and the rate with which reading skill can be acquired, as well as the eventual division of labor between phonological and semantic processes. Further, developmental reading disability manifests differently across writing systems, and may be related to different deficits in constitutive processes. Here we simulate some aspects of reading acquisition in Chinese and English using the same model for both writing systems. The contribution of semantic and phonological processing to literacy acquisition in the two languages is simulated, including specific effects of phonological and semantic deficits. Further, we demonstrate that similar patterns of performance are observed when the same model is trained on both Chinese and English as an “early bilingual”. The results are consistent with the view that reading skill is acquired by the application of statistical learning rules to mappings among print, sound and meaning, and that differences in the typical and disordered acquisition of reading skill between writing systems are driven by differences in the statistical patterns of the writing systems themselves, rather than differences in cognitive architecture of the learner.
Dietary patterns throughout childhood and associations with nutrient intakes
Authors: Cribb Victoria , Emmett Pauline , Northstone Kate
Published: September 2012

Objective

To examine how the dietary patterns of children at various time points throughout childhood relate to estimated nutrient intakes.

Design

FFQ at 3, 4, 7 and 9 years of age were completed by mothers. Dietary patterns were identified cross-sectionally using principal component analysis; ‘processed’, ‘health conscious’ and ‘traditional’ patterns were consistently obtained. Correlations between pattern scores and nutrient intakes and proportions of variance in nutrients explained by the patterns were calculated.

Setting

Avon Longitudinal Study of Parents and Children (ALSPAC), Bristol, UK.

Subjects

Children provided data between 3 and 9 years of age (n8010 to 10 023).

Results

Dietary patterns explained substantial proportions of the variance of the absolute intake for most nutrients (>25 % at 3 years of age, >40 % other ages). After energy adjustment, protein, fibre, K, Mg, Fe, Zn, folate, thiamin and vitamin B6continued to be well explained. Strong correlations were observed between the ‘processed’ pattern and macronutrients including energy (r= 0·481–0·619), total fat (r= 0·529–0·662) and total sugar (r= 0·475–0·693). However correlations with most micronutrients were reversed after energy adjustment, suggesting that the ‘processed’ pattern is energy-dense but nutrient-poor. The ‘health conscious’ and ‘traditional’ patterns were strongly positively correlated with protein, fibre and most micronutrients, whether energy adjusted or not. Higher scores on these patterns were associated with a better nutrient profile.

Conclusions

Dietary patterns explain a reasonable amount of the variation in the nutrient content of diets. Higher scores on the ‘health conscious’ and ‘traditional’ dietary patterns were related to better nutrient profiles; conversely, with higher scores on the ‘processed’ pattern the nutrient profile was poorer.
The prism of fundamental rights
Authors: Gerards Janneke
Published: September 2012

European Court of Human Rights – Suggestions for reducing case backlog and national criticism of the Court – Alternative to incremental case law and reasoning by analogy – Greater deference to national courts where individual interests, rather than fundamental rights are at stake – Guidelines to find objective criteria for the definition of fundamental rights – Sharper delineation of Convention rights – Procedural review preceding substantive review
Setting up the European External Action Service: an act of institutional balance
Authors: Erkelens Leendert , Blockmans Steven
Published: September 2012

European External Action Service – Treaty of Lisbon – High Representative of the Union for Foreign Affairs and Security Policy – combination with role of Vice President of the European Commission responsible for external action – Institutional balance between the Commission and the Council – Curtailment in practice of High Representative's ‘Vice Presidential’ powers – Hybrid approach toward role of EEAS: both intergovernmental and communitarian
Karriereunsicherheit, Zielkonflikte und Wohlbefinden bei Nachwuchswissenschaftlerinnen und -wissenschaftlern
Authors: Höge Thomas , Brucculeri Andreas , Iwanowa Anna N.
Published: September 2012

Der Beitrag beschreibt eine web-basierte Fragebogenstudie zur erlebten Karriere- und Arbeitsplatzunsicherheit, dem Erleben von Konflikten zwischen beruflichen und privaten Zielen, sowie dem Wohlbefinden von Nachwuchswissenschaftlerinnen und -wissenschaftlern in Deutschland, Österreich und Großbritannien. Untersucht wurden N = 702 Nachwuchswissenschaftler und -wissenschaftlerinnen aus unterschiedlichen Fachdisziplinen. Es zeigen sich signifikante Zusammenhänge zwischen der Karriereunsicherheit und dem Geschlecht der Befragten, der Art der Beschäftigung (befristet vs. unbefristet), dem Qualifikationsgrad (Post-Doc vs. Doktorand), der Fachdisziplin sowie der Ausprägung der proteischen Karriereorientierung. Neben einer höheren Karriereunsicherheit berichten die weiblichen Befragten auch über ausgeprägtere Konflikte zwischen beruflichen und privaten Zielen. Karriereunsicherheit und Zielkonflikte sind signifikante Prädiktoren für das Wohlbefinden der befragten Nachwuchswissenschaftler und -wissenschaftlerinnen. Der Zusammenhang zwischen Arbeitsplatzunsicherheit und Wohlbefinden wird durch die Karriereunsicherheit mediiert. Ländereffekte spielen hingegen eine untergeordnete Rolle.
Surface molecules on HaCaT keratinocytes after interaction with non‐thermal atmospheric pressure plasma
Authors: Haertel Beate , Hähnel Marcel , Blackert Susanne , Wende Kristian , von Woedtke Thomas , Lindequist Ulrike
Published: September 2012

Non‐thermal atmospheric‐pressure plasmas have been developed that will be used in future for several purposes, e.g. medicine. Living tissues and cells are at the focus of plasma treatment, e.g. to improve wound healing, or induce apoptosis and growth arrest in tumour cells. Detailed investigations of plasma‐cell interactions are needed. Cell surface adhesion molecules as integrins, cadherins or the EGFR (epidermal growth factor receptor) are of importance in wound healing and also for development of cancer metastasis. This study has focused on measurement of cell surface molecules on human HaCaT keratinocytes (human adult low calcium temperature keratinocytes) promoting adhesion, migration and proliferation as one important feature of plasma‐cell interactions. HaCaT keratinocytes were treated with plasma by a surface dielectric barrier discharge in air. Cell surface molecules and induction of intracellular ROS (reactive oxygen species) were analysed by flow cytometry 24 h after plasma treatment. Besides a reduction of cell viability a significant down‐regulation of E‐cadherin and the EGFR expression occurred. The influence on α2‐ and β1‐integrins was less pronounced, and expression of ICAM‐1 (intercellular adhesion molecule 1) was unaffected. The extent of effects depended on the exposure time of cells to the plasma and the treatment regimen. Intracellular level of ROS detected by the fluorescent dye H2DCFDA (2′,7′‐dichlorodihydrofluorescein diacetate) increased by plasma treatment, but it was neither dependent on the treatment time nor related to the different treatment regimens. Two‐dimensional cultures of HaCaT keratinocytes appear to be a suitable method of investigating plasma‐cell interactions.
ADAM23 knockdown promotes neuronal differentiation of P19 embryonal carcinoma cells by up‐regulating P27KIP1 expression
Authors: Wang Yingming , Sun Yaping , Qiao Shouyi
Published: September 2012

ADAM23 (a disintegrin and metalloprotease 23), a member of brain MDC (macrophage‐derived chemokine) family, is important for the development of CNS (central nervous system). P19 mouse embryonal carcinoma cells can differentiate into neurons when cultured in aggregates and induced with RA (retinoic acid). We have found that under conditions without RA induction, knocking down ADAM23 with RNAi (RNA interference) promoted neuronal differentiation, and similarly recombinant GST (glutathione transferase)‐ADAM23‐DIS protein inhibited neuronal differentiation of P19/ADAM23KD (P19/ADAM23‐knockdown) cells. In P19/ADAM23KD, there were more cells arrested in G1 phase than normal P19 cells, due to the up‐regulation of P57KIP2 and P27KIP1 expression. P27KIP1 was up‐regulated during the differentiation process of both P19/ADAM23KD cells without RA induction, and P19 cells with RA induction. Transient overexpression of P27KIP1 in P19 cells also promoted neuronal differentiation of P19 cells. The findings indicate that ADAM23 suppresses neuronal differentiation through its disintegrin domain, and Adam23 KD up‐regulates P27KIP1 in P19/ADAM23KD cells, one reason that P19/ADAM23KD cells can differentiate into neurons without RA induction.
Near-field enhanced ultraviolet resonance Raman spectroscopy using aluminum bow-tie nano-antenna
Authors: Li Ling , Fang Lim Shuang , Puretzky Alexander A. , Riehn Robert , Hallen H. D.
Published: September 2012

An aluminum bow-tie nano-antenna is combined with the resonance Raman effect in the deep ultraviolet to dramatically increase the sensitivity of Raman spectra to a small volume of material, such as benzene used here. We further demonstrate gradient-field Raman peaks for several strong infrared modes. We achieve a gain of ∼105 in signal intensity from the near field enhancement due to the surface plasmon resonance in the aluminum nanostructure. The on-line resonance enhancement contributes another factor of several thousands, limited by the laser line width. Thus, an overall gain of hundreds of million is achieved.
In-plane dielectric properties of epitaxial Ba0.7Sr0.3TiO3 thin films grown on GaAs for tunable device application
Authors: Yang Zhibin , Hao Jianhua
Published: September 2012

We have epitaxially deposited ferroelectric Ba0.7Sr0.3TiO3 (BST) thin films grown on GaAs substrate via SrTiO3 buffer layer by laser molecular beam epitaxy. Structural characteristics of the heterostructure were measured by various techniques. The in-plane dielectric properties of the heteroepitaxial structure under different applying frequency were investigated from −190 to 90 °C, indicating Curie temperature of the BST film to be around 52 °C. At room temperature, the dielectric constant of the heterostructure under moderate dc bias field can be tuned by more than 30% and K factor used for frequency agile materials is found to be close to 8. Our results offer the possibility to combine frequency agile electronics of ferroelectric titanate with the high-performance microwave capabilities of GaAs for room temperature tunable device application.
Dehydroxyl effect of Sn-doped silicon oxide resistance random access memory with supercritical CO2 fluid treatment
Authors: Tsai Tsung-Ming , Chang Kuan-Chang , Chang Ting-Chang , Syu Yong-En , Liao Kuo-Hsiao , Tseng Bae-Heng , Sze Simon M.
Published: September 2012

The tin-doped can supply conduction path to induce resistance switching behavior. However, the defect of tin-doped silicon oxide (Sn:SiOx) increased the extra leakage path lead to power consumption and joule heating degradation. In the study, supercritical CO2 fluids treatment was used to improve resistive switching property. The current conduction of high resistant state in post-treated Sn:SiOx film was transferred to Schottky emission from Frenkel-Poole due to the passivation effect. The molecular reaction model is proposed that the defect was passivated through dehydroxyl effect of supercritical fluid technology, verified by material analyses of x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy.
Multi-functional properties of CaCu3Ti4O12 thin films
Authors: Felix A. A. , Rupp J. L. M. , Varela J. A. , Orlandi M. O.
Published: September 2012

In this work, electric transport properties of CaCu3Ti4O12 (CCTO) thin films were investigated for resistive switching, rectifying and gas sensor applications. Single phase CCTO thin films were produced by polymeric precursor method (PPM) on different substrates and their electrical properties were studied. Films produced on LNO/Si substrates have symmetrical non-ohmic current-voltage characteristics, while films deposited on Pt/Si substrates have a highly asymmetrical non-ohmic behavior which is related to a metal-semiconductor junction formed at the CCTO/Pt interface. In addition, results confirm that CCTO has a resistive switching response which is enhanced by Schottky contacts. Sensor response tests revealed that CCTO films are sensitive to oxygen gas and exhibit n-type conductivity. These results demonstrate the versatility of CCTO thin film prepared by the PPM method for gas atmosphere or bias dependent resistance applications.
The inter-sublevel optical properties of a spherical quantum dot-quantum well with and without a donor impurity
Authors: Taş Hatice , Şahin Mehmet
Published: September 2012

In this study, we have investigated the inter-sublevel optical properties of a core/shell/well/shell spherical quantum dot (QD) with the form of quantum dot-quantum well heterostructure. In order to determine the energy eigenvalues and corresponding wave functions, the Schrödinger equation has been solved full numerically by using shooting method in the effective mass approximation for a finite confining potential. The inter-sublevel optical absorption and the oscillator strength between ground (1 s) and excited (1 p) states have been examined based on the computed energies and wave functions. Also, the effect of a hydrogenic donor impurity, located at the center of the multi-shell spherical quantum dot (MSQD), has been researched for different core radii (R1), shell thicknesses (Ts), and well widths (Tw) in certain potential. It is observed that the oscillator strengths and the absorption coefficients are strongly depend on the core radii and layer thicknesses of the MSQD.
Computer simulation study of collective dynamics in the glass former Ca(NO3)2·4H2O
Authors: Ribeiro Mauro C. C.
Published: September 2012

Time correlation functions of current fluctuations were calculated by molecular dynamics (MD) simulations in order to investigate sound waves of high wavevectors in the glass-forming liquid Ca(NO3)2·4H2O. Dispersion curves, ω(k), were obtained for longitudinal (LA) and transverse acoustic (TA) modes, and also for longitudinal optic (LO) modes. Spectra of LA modes calculated by MD simulations were modeled by a viscoelastic model within the memory function framework. The viscoelastic model is used to rationalize the change of slope taking place at k ∼ 0.3 Å−1 in the ω(k) curve of acoustic modes. For still larger wavevectors, mixing of acoustic and optic modes is observed. Partial time correlation functions of longitudinal mass currents were calculated separately for the ions and the water molecules. The wavevector dependence of excitation energies of the corresponding partial LA modes indicates the coexistence of a relatively stiff subsystem made of cations and anions, and a softer subsystem made of water molecules.
Revisiting plasma hysteresis with an electronically compensated Langmuir probe
Authors: Srivastava P. K. , Singh S. K. , Awasthi L. M. , Mattoo S. K.
Published: September 2012

The measurement of electron temperature in plasma by Langmuir probes, using ramped bias voltage, is seriously affected by the capacitive current of capacitance of the cable between the probe tip and data acquisition system. In earlier works a dummy cable was used to balance the capacitive currents. Under these conditions, the measured capacitive current was kept less than a few mA. Such probes are suitable for measurements in plasma where measured ion saturation current is of the order of hundreds of mA. This paper reports that controlled balancing of capacitive current can be minimized to less than 20 μA, allowing plasma measurements to be done with ion saturation current of the order of hundreds of μA. The electron temperature measurement made by using probe compensation technique becomes independent of sweep frequency. A correction of ≤45% is observed in measured electron temperature values when compared with uncompensated probe. This also enhances accuracy in the measurement of fluctuation in electron temperature as δTpk-pk changes by ∼30%. The developed technique with swept rate ≤100 kHz is found accurate enough to measure both the electron temperature and its fluctuating counterpart. This shows its usefulness in measuring accurately the temperature fluctuations because of electron temperature gradient in large volume plasma device plasma with frequency ordering ≤50 kHz.
Role of shocks and mix caused by capsule defects
Authors: Bradley P. A. , Cobble J. A. , Tregillis I. L. , Schmitt M. J. , Obrey K. D. , Glebov V. , Batha S. H. , Magelssen G. R. , Fincke J. R. , Hsu S. C. , Krasheninnikova N. S. , Murphy T. J. , Wysocki F. J.
Published: September 2012

An Eulerian code with a turbulent mix model is used to model a set of plastic (CH) ablator capsules with and without equatorial grooves. The “perfect” capsule results were used to calibrate simulations of capsules with equatorial grooves of different depths that provided information on increasingly perturbed implosions. Simulations with a turbulence model were able to calculate the same yield over mix (YOM) ratio (experiment/mix simulation) of 0.2 to 0.3 for thin (8-μm thick) and thick shell (15-μm thick) capsules with no grooves and thin capsules with shallow grooves. When the capsules have deep grooves, the YOM ratio increases to greater than unity, probably because the deformed shocks focus too strongly on the symmetry axis in our two-dimensional simulations. This is supported by a comparison of simulated and experimental x-ray images.
Millisecond kinetics of photo-darkening/bleaching in xGe45Se55-(1−x)As45Se55 chalcogenide amorphous films
Authors: Yan Qiqi , Jain Himanshu , Yang Guang , Ren Jing , Chen Guorong
Published: September 2012

Photosensitivity of thermally evaporated chalcogenide amorphous films of xGe45Se55-(1−x)As45Se55 (x = 0, 0.25, 0.5, 0.75, 1) composition is investigated when exposed to the laser light of 660 nm wavelength. The photo-induced effects transition from photodarkening (PD) to photobleaching (PB) as Ge45Se55 x increases from 0 to 1. The degree of PB correlates with the concentration of Ge–Ge homopolar bonds. The kinetics of PD and PB can be well described by a stretched exponential function. The dynamic response of PB is much faster than that of PD films in the present glass system.
Laser-produced aluminum plasma expansion inside a plastic plasma envelope
Authors: Kasperczuk A. , Pisarczyk T. , Chodukowski T. , Kalinowska Z. , Parys P. , Renner O. , Gus'kov S. Yu. , Demchenko N. N. , Ullschmied J. , Krousky E. , Pfeifer M. , Rohlena K. , Skala J.
Published: September 2012

Previous experimental results demonstrated that the plasma pressure decreases with the growing atomic number of the target material. In this context, a question arose if the Al plasma outflow could be collimated using the plastic plasma as a compressor. To solve this problem, an experiment using a plastic target with an Al cylindrical insert was performed. The focal spot diameter substantially larger than that of the insert ensured simultaneous heating both target materials. This experiment proved that a production of Al plasma jets collimated by an action of outer plastic plasma is feasible [Kasperczuk et al., Laser Part. Beams 30, 1 (2012)]. The results of investigations presented here provide additional information on distributions of electron temperature in the outflowing plasma and time and space characteristics of ion emission, both registered at bare and constrained-flow Al targets. The experiment was carried out at the Prague asterix laser system iodine laser facility. The laser provided a 250 ps (full width at half maximum) pulse with the energy of 130 J at the third harmonic frequency (λ3 = 0.438 μm). A plastic target with an Al cylindrical insert of 400 μm in diameter as well as a bare Al target (for comparison) was used. The focal spot diameter (ΦL) 1200 μm ensured the lateral pressure effect of the plastic plasma strong enough to guarantee the effective Al plasma compression. The electron temperature measurements have shown that such Al plasma compression is accompanied by the increase of its temperature, dominance of which starts at distance of 0.5 mm from the target surface. Measurements of ion emission characteristics confirm the earlier numerical simulation prediction that in these conditions the plasma expansion geometry is closer to planar. The constrained Al plasma jet is very narrow and its axial velocity is considerably larger than the velocity of freely expanding Al plasma stream. It means that the plastic plasma envelope, besides the Al plasma compression, also strongly accelerates the Al plasma in its axial motion.
Electronic structure and optical properties of β-FeSi2(100)/Si(001) interface at high pressure
Authors: Liu L. Z. , Wu X. L. , Liu X. X. , Shen J. C. , Li T. H. , Chu Paul K.
Published: September 2012

The electronic structure and optical absorption properties of the β-FeSi2(100)/Si(001) interface are investigated by first-principle calculation at high pressure. As the pressure increases, the optical gap decreases sharply, reaches a minimum, and then increases slowly. Structural analysis reveals that the Si(001) slab partially offsets the pressure exerted on the β-FeSi2 (100) interface, thus downshifting the lowest unoccupied electronic states of the interface and decreasing the optical gap. As the pressure increases further, this offsetting effect weakens and the optical gap increases again gradually. Hence, a high pressure plays an important role in the optical behavior.
Surface adsorption of colloidal brushes at good solvents conditions
Authors: Striolo Alberto
Published: September 2012

Monte Carlo simulations are presented for a minimal model of one spherical colloidal particle as it interacts with one attractive flat substrate. The colloidal particle is decorated by either 6 or 14 grafted polymer chains. The chains are always rather short, with their radius of gyration, estimated at infinite dilution in good solvent conditions, never larger than the spherical colloid diameter. Although all simulations are conducted under “good-solvent” conditions for the grafted polymer chains, we find that small changes in the polymer segment – polymer segment energetic interaction parameter can lead to significantly different scenarios. When the Lennard-Jones attraction is weak, 0.12 kBT, increasing the polymer length decreases the likelihood of colloidal adsorption, as expected. On the contrary, when the attraction is 0.18 kBT, increasing the length of the grafted polymer chains promotes the adsorption of the colloidal brush onto the surface. When the Lennard-Jones energetic parameter that describes polymer segment – polymer segment interactions is 0.15 kBT, as the length of the grafted polymer chains increases the probability of colloidal adsorption decreases to a minimum, and then increases. The results, explained in terms of a competition between entropic (due to the reduction in degrees of freedom available to the grafted polymer chains upon colloidal brush adsorption) and enthalpic driving forces (due to favorable colloid – surface and polymer segment – surface interactions), could be useful for controlling the circulation lifetime of liposomes within the blood stream, and optimizing solar energy harvesting by depositing colloidal particles on solid surfaces.
Topological classification of Brownian orbits
Authors: Tanaka Fumihiko
Published: September 2012

This paper presents the exact formula for the bivariate probability distribution function of a Brownian particle as a function of its position and velocity, whose orbit makes a specified number of turns around an infinite straight line. In the limit of large friction constant, the solution reduces to the well-known results for random Wiener paths. Topological entanglements of stiff polymers are discussed on the basis of this solution. The method to find the solution is applied to the velocity space of a Brownian motion, and the probability to find a closed path with a specified winding number is obtained. Hence, closed two-dimensional Brownian orbits are classified into regular homotopy classes, whose statistical weight is derived as a function of the total length and the friction constant.
Head-on collisions of electrostatic solitons in multi-ion plasmas
Authors: Verheest Frank , Hellberg Manfred A. , Hereman Willy A.
Published: September 2012

Head-on collisions between two electrostatic solitons are dealt with by the Poincaré-Lighthill-Kuo method of strained coordinates, for a plasma composed of a number of cold (positive and negative) ion species and Boltzmann electrons. The nonlinear evolution equations for both solitons and their phase shift due to the collision, resulting in time delays, are established. A Korteweg-de Vries description is the generic conclusion, except when the plasma composition is special enough to replace the quadratic by a cubic nonlinearity in the evolution equations, with concomitant repercussions on the phase shifts. Applications include different two-ion plasmas, showing positive or negative polarity solitons in the generic case. At critical composition, a combination of a positive and a negative polarity soliton is possible.
Hierarchical self-assembly of actin in micro-confinements using microfluidics
Authors: Deshpande Siddharth , Pfohl Thomas
Published: September 2012

We present a straightforward microfluidics system to achieve step-by-step reaction sequences in a diffusion-controlled manner in quasi two-dimensional micro-confinements. We demonstrate the hierarchical self-organization of actin (actin monomers—entangled networks of filaments—networks of bundles) in a reversible fashion by tuning the Mg2+ ion concentration in the system. We show that actin can form networks of bundles in the presence of Mg2+ without any cross-linking proteins. The properties of these networks are influenced by the confinement geometry. In square microchambers we predominantly find rectangular networks, whereas triangular meshes are predominantly found in circular chambers.
Polarization Coulomb field scattering in In0.18Al0.82N/AlN/GaN heterostructure field-effect transistors
Authors: Luan Chongbiao , Lin Zhaojun , Feng Zhihong , Meng Lingguo , Lv Yuanjie , Cao Zhifang , Yu Yingxia , Wang Zhanguo
Published: September 2012

Using the measured capacitance-voltage curves of Ni Schottky contacts with different areas and the current-voltage characteristics for the rectangular and circular In0.18Al0.82N/AlN/GaN heterostructure field-effect transistors (HFETs) at low drain-source voltage, we found that the Ohmic contact processing and the gate bias cause the irregular distribution of the polarization charges at the In0.18Al0.82N/AlN interface which generates the polarization Coulomb field, and the polarization Coulomb field scattering has an important influence on the two-dimensional electron gas electron mobility in both our rectangular and circular In0.18Al0.82N/AlN/GaN HFET devices as same as in AlGaN/AlN/GaN HFET devices.
Plasma flows in scrape-off layer of Aditya tokamak
Authors: Sangwan Deepak , Jha Ratneshwar , Brotankova Jana , Gopalkrishna M. V.
Published: September 2012

The magnetized Mach probe is used to make measurement of plasma flows in the scrape-off layer of the Aditya tokamak [R. Jha et al., Plasma Phys. Controlled Fusion 51, 095010 (2009)]. This probe is further used to measure dependencies of Mach number on local plasma densities and radial distances of the probe in the scrape-off layer. The measured Mach number has contributions from E×B drift, Pfrisch-Schlüter, and transport driven flows. We have determined that the toroidal flow is towards the ion side of the limiter and the poloidal flow direction is towards the contact of the last closed flux surface with the limiter.
Account of nonlocal ionization by fast electrons in the fluid models of a direct current glow discharge
Authors: Rafatov I. , Bogdanov E. A. , Kudryavtsev A. A.
Published: September 2012

We developed and tested a simple hybrid model for a glow discharge, which incorporates nonlocal ionization by fast electrons into the “simple” and “extended” fluid frameworks. Calculations have been performed for an argon gas. Comparison with the experimental data as well as with the hybrid (particle) and fluid modelling results demonstated good applicability of the proposed model.
Superhydrophobic surfaces cannot reduce ice adhesion
Authors: Chen Jing , Liu Jie , He Min , Li Kaiyong , Cui Dapeng , Zhang Qiaolan , Zeng Xiping , Zhang Yifan , Wang Jianjun , Song Yanlin
Published: September 2012

Understanding the mechanism of ice adhesion on surfaces is crucial for anti-icing surfaces, and it is not clear if superhydrophobic surfaces could reduce ice adhesion. Here, we investigate ice adhesion on model surfaces with different wettabilities. The results show that the superhydrophobic surface cannot reduce the ice adhesion, and the ice adhesion strength on the superhydrophilic surface and the superhydrophobic one is almost the same. This can be rationalized by the mechanical interlocking between the ice and the surface texture. Moreover, we find that the ice adhesion strength increases linearly with the area fraction of air in contact with liquid.
Modulation doping to control the high-density electron gas at a polar/non-polar oxide interface
Authors: Cain Tyler A. , Moetakef Pouya , Jackson Clayton A. , Stemmer Susanne
Published: September 2012

A modulation-doping approach to control the carrier density of the high-density electron gas at a prototype polar/non-polar oxide interface is presented. It is shown that the carrier density of the electron gas at a GdTiO3/SrTiO3 interface can be reduced by up to 20% from its maximum value (∼3 × 1014 cm−2) by alloying the GdTiO3 layer with Sr. The Seebeck coefficient of the two-dimensional electron gas increases concurrently with the decrease in its carrier density. The experimental results provide insight into the origin of charge carriers at oxide interfaces exhibiting a polar discontinuity.
Flat bands near Fermi level of topological line defects on graphite
Authors: Feng Lei , Lin Xianqing , Meng Lan , Nie Jia-Cai , Ni Jun , He Lin
Published: September 2012

Here, we report direct experimental evidence for the presence of flat bands, close to the Fermi level, in one-dimensional topological defects of graphite. The flat bands are manifested by a pronounced peak in the tunnelling density of states. Our ab initio calculations indicate that the flat bands with vanishing Fermi velocity originate from sp2 dangling bonds (with antibonding nature) of undercoordinated carbon atoms at the edges of the defects. We further demonstrate that the presence of flat bands could be an inevitable behavior of 1D defects of graphene/graphite with undercoordinated carbon atoms at the edges of the defects.
Defect mechanisms in high resistivity BaTiO3–Bi(Zn1/2Ti1/2)O3 ceramics
Authors: Raengthon Natthaphon , DeRose Victoria J. , Brennecka Geoffrey L. , Cann David P.
Published: September 2012

The defect mechanisms that underpin the high energy density dielectric 0.8BaTiO3–0.2Bi(Zn1/2Ti1/2)O3 were investigated. Characterization of the nominally stoichiometric composition revealed the presence of a Ti3+-related defect center, which is correlated with lower resistivities and an electrically heterogeneous microstructure. In compositions with 2 mol. % Ba-deficiency, a barium vacancy-oxygen vacancy pair (VBa−VO), acted as an electron-trapping site. This defect was responsible for a significant change in the transport behavior with a high resistivity and an electrically homogeneous microstructure.
Effect of electrode materials on the scaling behavior of energy density in Pb(Zr0.96Ti0.03)Nb0.01O3 antiferroelectric films
Authors: Ge Jun , Pan Gang , Remiens Denis , Chen Ying , Cao Fei , Dong Xianlin , Wang Genshui
Published: September 2012

Antiferroelectric Pb(Zr, Nb, Ti)O3 (PZNT) films were deposited via a sol-gel process on Pt(111)/Ti/SiO2/Si, LaNiO3- and La0.5Sr0.5CoO3-buffered Si substrate. The scaling behavior of the energy density W of antiferroelectric films was investigated. The scaling behavior of W against frequency f of PZNT on LaNiO3-buffered Si takes the form of W ∝ f0.08, which differs significantly from that form of W ∝ f−0.14 of PZNT on La0.5Sr0.5CoO3-buffered Si. This indicates that the scaling relations of W vary substantially as bottom electrodes change and might be closely related to the variation of nonuniform strain field and depolarization field within the AFE films.
Scanning internal photoemission microscopy for the identification of hot carrier transport mechanisms
Authors: Differt D. , Pfeiffer W. , Diesing D.
Published: September 2012

Linear and nonlinear internal photoemission in a thin-film metal-insulator-metal heterosystem, i.e., a Ta-TaOx-Ag junction, together with surface reflectivity are mapped with a lateral resolution of better than 5 μm. The spatial correlation of the different signals and time-resolved internal photoemission spectroscopy reveal excitation mechanisms and ballistic hot carrier injection. The internal photoemission yield variation with Ag layer thickness is quantitatively explained by above-barrier injection. The hot-spot-like behavior of the two-photon induced internal photoemission observed for short pulse excitation is attributed to local field enhancements because of Ag-film thickness reduction and plasmonic effects at structural defects.
Properties of magnetic nickel/porous-silicon composite powders
Authors: Nakamura Toshihiro , Adachi Sadao
Published: September 2012

The magnetic and photoluminescence (PL) properties of nickel/porous-silicon (Ni/PSi) composite powders are investigated. Ni/PSi composite powders are prepared by stain etching of Si powder in a HF/HNO3 solution followed by electroless plating of Ni nanoparticles on the stain-etched PSi powder in a NiCl2 solution. The Ni/PSi powders exhibit hydrophillicity, superparamagnetism caused by the deposited Ni nanoparticles, and orange-red PL owing to the nanostructured PSi surface. The degree of magnetization decreases with increasing Ni plating time, indicating its dependence on the size of the Ni nanoparticles. The Ni/PSi composite powders also show a stronger magnetization as compared to that of the Ni-particle-plated Si powder. The stronger magnetization results from the larger surface area of PSi. The PL intensity, peak wavelength, and lifetime of Ni/PSi are strongly dependent on the NiCl2 concentration. This dependence is due to the different thickness of the oxide overlayer on the PSi surface formed during the Ni plating process. The existence of the oxide overlayer also results in a small change in the PL intensity against excitation time.
Media, Religion and the Marketplace in the Information Economy: Evidence from Singapore
Authors: Poon Jessie P H , Huang Shirlena , Cheong Pauline Hope
Published: September 2012

In this paper we suggest that the exchange of communication in a mediatized environment is transforming the nature of transactions in the religious marketplace. In this economy of religious informational exchanges, digitalization facilitates a process of mediatization that converts religious performance into forms suitable for commodification and commoditization. The intersection of digital media, religion, and the marketplace is demonstrated in the context of mega Protestant and Buddhist organizations in Singapore. We show how these large organizations embed media relations in their sacred spaces through a process of hybridization. In turn, hybrid spaces are converted into material outputs that may be readily transacted in real and virtual spaces. Hybridization attends to a postmodern audience and consumers who value experience and sensorial stimulations. It integrates retail, entertainment, and the aesthetics into a space of ascetic performance that is digitally transportable. Digital transactional spaces thrive on the abundance of information, and information multiplies when communication is unfettered by the absence of proprietary safeguards. The religious marketplace may therefore be understood as a medially driven performance space where points of interaction are digitally convertible for further reproduction, reconsumption, and redistribution in media form.
Consumer Satisfaction with Local Retail Diversity in the UK: Effects of Supermarket Access, Brand Variety, and Social Deprivation
Authors: Clarke Ian , Kirkup Malcolm , Oppewal Harmen
Published: September 2012

Levels of concentration in the grocery sector have led to concerns about reduced diversity of local retail provision and its potential negative effects on consumer welfare and choice. Using empirical evidence from a study of consumer perceptions of retail choice across nine purposefully sampled neighbourhoods in the city of Worcester in the UK, the paper illuminates consumer satisfaction with local provision and investigates how satisfaction varies with the local mix of grocery stores. The study adopts a stated-preference approach with realistic but hypothetical scenarios being presented to consumers in which the level, form, brand composition, and accessibility of local retail provision is systematically varied to gauge the sensitivity of householders in different types of neighbourhoods to variations in local retail assortments. The contributions of the paper are reflected in three main findings: (1) residents value having a large supermarket close by and reveal that they value diversity of provision rather than overconcentration; (2) consumers in deprived areas overall display greater satisfaction for the same offer than consumers in less deprived areas; and (3) although small stores in a local store assortment significantly contribute to reducing dissatisfaction with the local retail offer, they contribute little to achieving higher levels of consumer satisfaction. The study stresses the need for planners and policy makers to maximise choice and welfare through both the number and the diversity of stores in local neighbourhood areas.
Land-Conservation Strategies: The Dynamic Relationship between Acquisition and Land-Use Planning
Authors: Gerber Jean-David , Rissman Adena R
Published: September 2012

Nonprofit organizations often pursue land acquisition as a nonpolitical, private property rights approach to conservation of ecological and cultural resources. Yet acquisition and regulatory land-use planning are intertwined, both in terms of political strategies and conservation outcomes. Our objectives are (1) to understand the relationship between the acquisition strategies of land trusts and their involvement in land-use planning and zoning, and (2) to examine how the interactions between acquisition and land-use planning may shape conservation outcomes. We focus on the strategies of The Nature Conservancy, one of the largest conservation NGOs in the United States. Drawing from an institutional analysis framework, we compare case studies from Tehama and Monterey Counties, California. Through semistructured interviews, analysis of land-use plans and conservation-easement agreements, and GIS mapping we examine political strategies and conservation outcomes. Our analysis reveals that acquisition strategies and the regulatory context influence each other strongly, but that tensions between the politics of these strategies challenge conservation actors to deploy both effectively. Finally, we develop themes for future research, suggesting that the implementation and assessment of regional conservation efforts would benefit from an integrated strategy that recognizes the synergistic linkages between acquisition and regulatory land-use planning.
Business and Professional Networks: Scope and Outcomes in Oxfordshire
Authors: Smith Helen Lawton , Romeo Saverio , Virahsawmy Malika
Published: September 2012

This paper examines the relationship between formal networks, such as business and occupationally based professional networks, and place in determining network patterns and types in regional economic development. It distinguishes between ‘network-rich’ and ‘network-poor’ regions and considers why and how formal networks operate as a service and a resource to participants and as components of regional business infrastructures. Formal networks in the Oxfordshire to Cambridge Arc in the UK are used to illustrate these points.