bluuebunny/crossref_metadata_2025 huggingface dataset:
Tensions between Medical Professionals and Patients in Mainland China
Authors: ZHANG XINQING , SLEEBOOM-FAULKNER MARGARET
Published: May 2011

In China, state investment into public hospitals has radically decreased since the early 1980s and has brought on the dismantling of the healthcare system in most parts of the country, especially in rural areas. As a result of this overhaul, the majority of public hospitals have needed to compete in the so-called socialist market economy. The market economy stimulated public hospitals to modernize, take on highly qualified medical professionals, and dispense new therapies and drugs. At same time, liberalization has clearly affected the attitude and behavior of both medical professionals and the general public. The public has many concerns about the healthcare system for various reasons: there are long hospital waiting lists, patients experience difficulties in obtaining an appointment to see a qualified doctor, and, over the past decades, there has been an increase in out-of-pocket healthcare expenditure. These and other changes in post-reform China have radically reshaped the doctor–patient interaction, which is increasingly eroded by tension and violence.
CQ Sources/Bibliography
Authors: Anton Bette
Published: May 2011

These CQ Sources were compiled by Bette Anton.
A Comparison of Student Performance between Two Instructional Delivery Methods for a Healthcare Ethics Course
Authors: STODDARD HUGH A. , SCHONFELD TOBY
Published: May 2011

Healthcare ethics has become part of the standard curriculum of students in the health professions. The goals of healthcare ethics education are to give students the skills they need to identify, assess, and address ethical issues in clinical practice and to develop virtuous practitioners. Incorporating the medical humanities into medical school, for example, is intended to foster empathy and professionalism among students and to provide mechanisms for enhanced physician well-being. Yet, despite the long-standing inclusion of the humanities in nursing curricula, increases in the amount and kinds of scientific knowledge essential for clinical practice has resulted in the erosion of the “humanistic arts” from nursing education. One potential solution to this challenge comes with the increase in interprofessional education, where students in a variety of healthcare professions programs come together to learn about issues common to all healthcare fields.
The potential role of small fish species in improving micronutrient deficiencies in developing countries: building evidence
Authors: Kawarazuka Nozomi , Béné Christophe
Published: May 2011

Objective

To build a comprehensive overview of the potential role of fish in improving nutrition with respect to certain micronutrient deficiencies in developing countries.

Design

A comprehensive literature review was completed. For this the electronic library databases ASFA, CABD and Scopus were systematically searched and relevant references cited in these sources were carefully analysed. The search terms used were ‘fish’, ‘small fish species’, ‘micronutrients’, ‘food-based strategies’, ‘fish consumption’ and ‘developing countries’. The quality of data on nutritional analyses was carefully reviewed and data that lacked proper information on methods, units and samples were excluded.

Results

The evidence collected confirmed the high levels of vitamin A, Fe and Zn in some of the small fish species in developing countries. These small fish are reported to be more affordable and accessible than the larger fish and other usual animal-source foods and vegetables. Evidence suggests that these locally available small fish have considerable potential as cost-effective food-based strategies to enhance micronutrient intakes or as a complementary food for undernourished children. However, the present review shows that only a few studies have been able to rigorously assess the impact of fish consumption on improved nutritional status in developing countries.

Conclusions

Further research is required in areas such as determination of fish consumption patterns of poor households, the nutritional value of local fish and other aquatic animals and the impact of fish intake on improved nutritional status in developing countries where undernutrition is a major public health problem.
Mutually agreed solutions under the WTO Dispute Settlement Understanding: An Analytical Framework after theSoftwood LumberArbitration
Authors: ALVAREZ-JIMÉNEZ ALBERTO
Published: May 2011

The unprecedented enforcement of the mutually agreed solution (MAS) in the WTOSoftwood Lumberdisputes – but outside the WTO dispute settlement system – and the recent use of MAS to resolve important trade disputes should trigger a hard look at these dispute settlement instruments provided for by the DSU. This article seeks to provide a detailed framework of analysis of MAS under the DSU that allows the WTO dispute settlement system to adjudicate MAS-related disputes. WTO Members should not go outside the system to enforce MAS. The article illustrates that MAS can create binding obligations and that MAS are WTO law, given the explicit reference to them in the DSU, their intimate relation with the WTO-covered agreements and the requirement for compliance with these agreements. In addition, the article offers an interpretation of the DSU that allows panels and the Appellate Body to regard MAS as applicable law. This interpretation is offered in the view that there is no policy reason to sustain that these controversies – always fully related to WTO rights and obligations and framed under the corners of the covered agreements – have to be resolved by an adjudication system other than that of the WTO.
Controlled studies further the development of practical guidelines to manage dodder (Cuscuta gronovii) in cranberry production with short-term flooding
Authors: O'Connell James M. , Sandler Hilary A. , Adler Lynn S. , Caruso Frank L.
Published: May 2011

Flooding is an inexpensive cultural practice used for pest management in Massachusetts cranberry (Vaccinium macrocarponAit.) production. This project examined the use of short-term floods (<72 h) for dodder (Cuscuta gronoviiWilld.) management under controlled conditions. Using incubators, seed was submerged in water for 0, 24 and 48 h at 10, 15 and 20°C (simulating spring water temperatures) and 0, 12, 24, 36 and 48 h at 15, 20 and 25°C (simulating summer water temperatures). Two 1-year controlled studies (field and greenhouse) evaluated three flood durations (0, 24 and 48 h) and four flood initiations (1, 2, 3 and 4 weeks after early seedling emergence (AEE)). Treated seeds were planted to cranberry vines and to Petri dishes; percent germination, degree of dodder attachment and dodder biomass data were collected. Treatments had limited effect on seed germination. Flooding 4 weeks AEE resulted in the lowest mean attachment ratings and dodder stem biomass on cranberry. This preliminary work provides evidence that flooding may retard dodder stem growth rather than reducing seed germination and that floods initiated after some time has elapsed after early emergence may be more effective than those initiated closer to the time of seedling emergence. More information is needed to thoroughly understand the processes involved; however, small projects such as this can provide interim guidelines that growers can immediately consider when deciding on a dodder management program.
The accretion of aeolian dust in soils of the San Juan Mountains, Colorado, USA
Authors: Lawrence Corey R. , Neff Jason C. , Farmer G. Lang
Published: May 2011

Recent observations suggest a contemporary aeolian dust flux of at least 5–10 g m−2 yr−1 to high‐elevation ecosystems of the San Juan Mountains of southwestern Colorado. To better quantify the influence of dust on San Juan soil geochemistry, we used Sr and Nd isotopic mixing models to estimate the total mass of accreted dust in soils of two alpine basins underlain by bedrocks of different geochemical composition. In order to minimize the potentially confounding effects caused by transient soil pools of Sr and Nd, we implemented a sequential leaching procedure that isolates the residual mineral fraction of soils and their putative parent materials, including local saprolite and exogenous dust inputs. Using this approach, we calculated masses of accreted dust in soils, which were similar across the two isotopic tracers and differing local geologies. Long‐term rates of dust accretion were estimated to be slightly higher than contemporary rates of dust deposition. We conclude that dust inputs comprise from 10% to 40% of the total soil mass in these ecosystems. Our observations suggest that dust inputs have exerted a primary control on soil development in the San Juan Mountains and have likely influenced the physical and chemical characteristics of soils in this region.
Hydrological variability in Florida Straits during Marine Isotope Stage 5 cold events
Authors: Bahr André , Nürnberg Dirk , Schönfeld Joachim , Garbe‐Schönberg Dieter
Published: May 2011

Modeling and proxy studies indicate that a reduction of Atlantic Meridional Overturning Circulation (AMOC) strength profoundly impacts temperatures and salinities in the (sub)tropical Atlantic, especially on subsurface levels. While previous studies focused on prominent periods of AMOC reduction during the last deglaciation, we aim to test whether similar reconfigurations of the subtropical hydrography occurred during the moderate climatic alterations punctuating the last interglacial Marine Isotope Stage (MIS) 5. Here, we present temperature and salinity records from a Florida Straits core by combining δ18O and Mg/Ca analyses on surface (Globigerinoides ruber, white) and deep‐dwelling (Globorotalia crassaformis) foraminifera covering MIS 5 in high resolution. The data reveal increasing salinities at intermediate depths during interglacial cooling episodes, decoupled from relatively stable surface conditions. This probably indicates the spatial expansion of saline subtropical gyre waters due to enhanced Ekman downwelling and might also point to a changed density structure and altered geostrophic balance in Florida Straits. Notably, these oceanographic alterations are not consistently occurring during periods of AMOC reduction. The data suggest that the expansion of gyre waters into Florida Straits was impeded by the increasing influence of Antarctic Intermediate Water (AAIW) from MIS 5.5 to ∼107 kyr BP. Afterward, increasingly positive benthic δ13C values imply a recession of AAIW, allowing the temporary expansion of gyre waters into Florida Straits. We argue that the inferred transient subtropical salt accumulation and warm pool expansion might have played a pivotal role in reinvigorating meridional overturning and dampen the severity of interglacial cold phases.
On the use of the method of moments in plasmonic applications
Authors: Vandenbosch Guy A. E. , Volski V. , Verellen N. , Moshchalkov V. V.
Published: May 2011

In the last 40 years the method of moments (MOM) has been a cornerstone in the field of computational electromagnetics. Traditionally, this method has been used to solve integral equations formulated for antennas and other components in the microwave frequency range and below. In this paper, the application of MOM in the field of plasmonics is briefly reviewed. First, existing literature is referenced. Then the differences with the classical implementations are pointed out. Finally, its applicability, advantages, and disadvantages are discussed. This is done by comparing it with a numerical finite difference time domain solver well‐known in the plasmonics research community for a number of example structures. It is shown that also at these higher frequencies, namely in the IR and optical range, MOM is a very powerful technique.
Design soil moisture estimation by comparing continuous and storm‐based rainfall‐runoff modeling
Authors: Camici S. , Tarpanelli A. , Brocca L. , Melone F. , Moramarco T.
Published: May 2011

In recent years local, national, and international authorities have showed an increasing awareness of flood and inundation hazard, likely due to the large floods which occurred in the past years in many regions of the world. In this context, the estimation of the design flood values to be adopted for flood risk assessment or floodplain management represents a crucial factor. In the case of ungauged or scarcely gauged catchments where a sufficiently long discharge time series is missing, a relevant uncertainty is involved in the flood frequency analysis and a possible solution to reduce this uncertainty is the application of continuous simulation (CS) approaches. Because of the complex structure of this type of approaches and pursuing the parameters parsimony criteria, in the hydrological practice the approaches based on the design storm (DS) estimation are more widely known and applied, mainly for their simplicity. However, one major limit of the DS method is the choice of the “design soil moisture” conditions, representing a critical parameter for assessing the initial wetness of the basin. To that end, this study of investigating six subcatchments of the upper Tiber River basin (Central Italy), with drainage area ranging from 13 to 284 km2, proposes a procedure based on the application of the CS approach as a tool to define the design soil moisture to be afterwards incorporated into the more simple DS method. For each catchment, the procedure consists of (1) stochastic generation of long synthetic rainfall and temperature series starting from observed hourly data; (2) application of a lumped continuous rainfall‐runoff model to generate synthetic discharge series and, hence, to obtain the corresponding flood frequency curves; (3) estimation of the design soil moisture, for each return period, by varying in the DS approach the initial wetness conditions of the catchment so that the peak discharge estimated by the DS method matches the one given by the synthetic flood frequency curve. Moreover, in order to apply the more simple DS approach avoiding the use of the CS one, a preliminary analysis to regionalize the design soil moisture as a function of the geo‐morphological characteristics and the return period is also shown.
Simulating unsteady flow, anabranching, and hyporheic dynamics in a glacial meltwater stream using a coupled surface water routing and groundwater flow model
Authors: Koch J. C. , McKnight D. M. , Neupauer R. M.
Published: May 2011

Flooding affects ecosystems by transporting water and solutes across aquatic‐terrestrial interfaces, removing nutrient and organic substrate limitations, and spurring biogeochemical activity. Few studies have considered the influence of flooding on surface water–groundwater interactions. This research examines the temporally variable water storage and exchange in a stream in the McMurdo Dry Valleys (MDV) of Antarctica, where diel flood pulses occur due to glacial melt. Several MDV streams display truncated discharge peaks, suggesting water storage between the source glacier and the gauging station. We tested the hypothesis that stream braids and subsurface water storage contribute to the difference between glacial melt and stream outflow hydrographs by constructing a coupled surface water routing and subsurface water flow model. This model routes water into stream braids at high flows and allows this water to infiltrate and return to the stream via subsurface flow paths as flows recede. Our simulation demonstrates the importance of surface–subsurface water interactions in controlling the hydrograph shape. Maximum simulated discharge was sensitive to storage parameters including aquifer depth and the flooding threshold, while minimum discharge was sensitive to hydraulic conductivity. Subsurface storage volume varied by 38% over a diel cycle and stream‐subsurface exchange rates varied from 0 to 0.19 m3 h−1 m−1, with exchange from the stream to the subsurface during high flows, and vice versa at low flows. These results underscore how unsteady flow can increase hyporheic interactions and ecosystem productivity, and provide support for maintaining natural stream morphology and flow regimes.
How restructuring river connectivity changes freshwater fish biodiversity and biogeography
Authors: Lynch Heather J. , Campbell Grant Evan H. , Muneepeerakul Rachata , Arunachalam Muthukumarasamy , Rodriguez‐Iturbe Ignacio , Fagan William F.
Published: May 2011

Interbasin water transfer projects, in which river connectivity is restructured via man‐made canals, are an increasingly popular solution to address the spatial mismatch between supply and demand of fresh water. However, the ecological consequences of such restructuring remain largely unexplored, and there are no general theoretical guidelines from which to derive these expectations. River systems provide excellent opportunities to explore how network connectivity shapes habitat occupancy, community dynamics, and biogeographic patterns. We apply a neutral model (which assumes competitive equivalence among species within a stochastic framework) to an empirically derived river network to explore how proposed changes in network connectivity may impact patterns of freshwater fish biodiversity. Without predicting the responses of individual extant species, we find the addition of canals connecting hydrologically isolated river basins facilitates the spread of common species and increases average local species richness without changing the total species richness of the system. These impacts are sensitive to the parameters controlling the spatial scale of fish dispersal, with increased dispersal affording more opportunities for biotic restructuring at the community and landscape scales. Connections between isolated basins have a much larger effect on local species richness than those connecting reaches within a river basin, even when those within‐basin reaches are far apart. As a result, interbasin canal projects have the potential for long‐term impacts to continental‐scale riverine communities.
UV irradiation resistance‐associated gene suppresses apoptosis by interfering with BAX activation
Authors: Yin Xiaocheng , Cao Lizhi , Kang Rui , Yang Minghua , Wang Zhuo , Peng Yanhui , Tan Yanfang , Liu Liying , Xie Min , Zhao Yiming , Livesey Kristen M , Tang Daolin
Published: May 2011

Ultraviolet irradiation resistance‐associated gene (UVRAG) is a well‐known regulator of autophagy by promoting autophagosome formation and maturation. However, little is known about the non‐autophagic functions of UVRAG. Here, we present evidence that UVRAG functions as an unusual BCL2‐associated X protein (Bax) suppressor to regulate apoptosis. Chemotherapy and radiation induces UVRAG expression and subsequently upregulates autophagy and apoptosis in tumour cells. Depletion of UVRAG expression by RNA interference renders tumour cells more sensitive to chemotherapy‐ and radiation‐induced apoptosis in vitro and in vivo. Moreover, UVRAG interacts with Bax, which inhibits apoptotic stimuli‐induced mitochondrial translocation of Bax, reduction of mitochondrial membrane potential, cytochrome c release and activation of caspase‐9 and ‐3. Our findings show that UVRAG has an essential role in the intrinsic mitochondrial pathway of apoptosis by regulating the localization of Bax. This pathway represents a target for clinical intervention against tumours.
Transformation of eEF1Bδ into heat‐shock response transcription factor by alternative splicing
Authors: Kaitsuka Taku , Tomizawa Kazuhito , Matsushita Masayuki
Published: May 2011

Protein translation factors have crucial roles in a variety of stress responses. Here, we show that eukaryotic elongation factor 1Bδ (eEF1Bδ) changes its structure and function from a translation factor into a heat‐shock response transcription factor by alternative splicing. The long isoform of eEF1Bδ (eEF1BδL) is localized in the nucleus and induces heat‐shock element (HSE)‐containing genes in cooperation with heat‐shock transcription factor 1 (HSF1). Moreover, the amino‐terminal domain of eEF1BδL binds to NF‐E2‐related factor 2 (Nrf2) and induces stress response haem oxygenase 1 (HO1). Specific inhibition of eEF1BδL with small‐interfering RNA completely inhibits Nrf2‐dependent HO1 induction. In addition, eEF1BδL directly binds to HSE oligo DNA in vitro and associates with the HSE consensus in the HO1 promoter region in vivo. Thus, the transcriptional role of eEF1BδL could provide new insights into the molecular mechanism of stress responses.
Lipid models for united-atom molecular dynamics simulations of protein
Authors: Kukol Andreas
Published: May 2011

Molecular dynamics (MD) simulations of biomolecules are performed at various levels of atomic detail from all-atom models to coarse grained models. United-atom models are at an intermediate level, in which non-polar hydrogen atoms are subsumed into their adjacent carbon-atom reducing the number of particles for a DPPC lipid molecule by 60%. United-atom models of the lipids DPPC, DMPC, POPC and POPG in the GROMOS96 53a6 force field were developed, that reproduced experimental properties of lipid bilayers without assumption of a constant surface area or inclusion of surface pressure. In the absence of experimental data a surface per lipid area for the negatively charged POPG of 0.700±0.007 nm2 was obtained that is higher than 0.53 to 0.56 nm2 reported in previous simulation studies in the literature. It is argued that MD simulations of anionic bilayers may have underestimated the steric requirements of sodium counter ions entering the head group region in order to compensate the negative charge. The use of the DMPC GROMOS96 53a6 model was evaluated in an MD simulation of the ErbB2 transmembrane peptide and showed closer agreement with the NMR-derived structure than the GROMOS87 force field that was most commonly used for membrane protein simulations previously. Lipid topologies and coordinates are available via LipidBook (http://lipidbook.bioch.ox.ac.uk/).
Influence of different breathing patterns on heart rate variability indices and reproducibility during experimental endotoxaemia in human subjects
Authors: Kox Matthijs , Pompe Jan C. , van der Hoeven Johannes G. , Hoedemaekers Cornelia W. , Pickkers Peter
Published: May 2011

HRV (heart rate variability) analysis is a widely employed method to assess cardiac autonomic nervous system activity. Accurate HRV measurement is critical to its value as a diagnostic and prognostic tool. Different breathing patterns may affect HRV, but results obtained under static conditions are conflicting. HRV indices decrease considerably during systemic inflammation evoked by experimental endotoxaemia, enabling the determination of the effects of different breathing patterns on HRV in a dynamic setting. We investigated the impact of different breathing patterns on short-term HRV measurements during experimental endotoxaemia. Furthermore, we assessed whether paced breathing improved HRV reproducibility. Twelve healthy male volunteers received an intravenous bolus (2 ng/kg of body weight) of endotoxin [LPS (lipopolysaccharide), derived from Escherichia coli O:113] on two occasions with an interval of 2 weeks. Five-minute HRV recordings were performed just prior to LPS administration and hourly thereafter until 8 h post-LPS. Three breathing protocols were employed every hour: (i) spontaneous breathing, (ii) metronome-guided breathing at the subject's normal respiratory rate (‘paced’) and (iii) metronome-guided breathing at 150% of the subject's normal respiratory rate (‘mild hyperventilation’). LPS administration resulted in a sharp decrease in all of the HRV indices measured, which was similar during both LPS administrations. Neither paced breathing nor mild hyperventilation influenced HRV indices compared with spontaneous breathing. Paced breathing did not improve reproducibility as it did not exert a significant effect on intra-subject coefficients of variation and intra-class correlation coefficients (calculated between both visits). In conclusion, over a wide range of HRV magnitudes during experimental endotoxaemia, neither paced breathing nor mild hyperventilation affected HRV indices. Moreover, paced breathing did not result in a significant improvement in reproducibility. Therefore employing a paced breathing protocol is not required to obtain valid HRV data during endotoxaemia.
Development of Compton radiography of inertial confinement fusion implosions
Authors: Tommasini R. , Hatchett S. P. , Hey D. S. , Iglesias C. , Izumi N. , Koch J. A. , Landen O. L. , MacKinnon A. J. , Sorce C. , Delettrez J. A. , Glebov V. Yu. , Sangster T. C. , Stoeckl C.
Published: May 2011

An important diagnostic tool for inertial confinement fusion will be time-resolved radiographic imaging of the dense cold fuel surrounding the hot spot. The measurement technique is based on point-projection radiography at photon energies from 60 to 200 keV where the Compton effect is the dominant contributor to the opacity of the fuel or pusher. We have successfully applied this novel Compton radiography technique to the study of the final compression of directly driven plastic capsules at the OMEGA facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. The radiographs have a spatial and temporal resolution of ∼10 μm and ∼10 ps, respectively. A statistical accuracy of ∼0.5% in transmission per resolution element is achieved, allowing localized measurements of areal mass densities to 7% accuracy. The experimental results show 3D nonuniformities and lower than 1D expected areal densities attributed to drive asymmetries and hydroinstabilities.
Evolution of glassy gratings with variable aspect ratios under surface diffusion
Authors: Malshe Rohit , Ediger M. D. , Yu Lian , de Pablo J. J.
Published: May 2011

The structural evolution of surface gratings on a glassy material is investigated by means of molecular simulations. The gratings provide a means to probe surface diffusion in the vicinity of the glass transition temperature. A theory by Mullins [J. Appl. Phys. 30, 77 (1959)]10.1063/1.1734979 is used to extract qu-antitative measures of surface diffusivity that rely on calculation of grating amplitude as a function of time. The simulations are implemented in the context of a model binary glass mixture [S. S. Ashwin and S. Sastry, J. Phys.: Condens. Matter 15, S1253 (2003)10.1088/0953-8984/15/11/343]. We find that surface diffusion is faster than bulk diffusion by several orders of magnitude, consistent with recent experimental data for an organic glass former. The diffusivities extracted by the grating-decay approach are consistent with those estimated on the basis of mean–squared particle displacements. The grating-decay approach, however, is more efficient than traditional techniques based on Einstein's diffusion equation. Grating decay is also more versatile and is shown to be applicable in a variety of sample geometries.
Equivalence problem for the orthogonal webs on the 3-sphere
Authors: Cochran Caroline M. , McLenaghan Raymond G. , Smirnov Roman G.
Published: May 2011

We solve the equivalence problem for the orthogonally separable webs on the 3-sphere under the action of the isometry group. This continues a classical project initiated by Olevsky in which he solved the corresponding canonical forms problem. The solution to the equivalence problem together with the results by Olevsky forms a complete solution to the problem of orthogonal separation of variables for the Hamilton–Jacobi equation defined on the 3-sphere via orthogonal separation of variables. It is based on invariant properties of characteristic Killing tensors in addition to properties of the corresponding algebraic curvature tensor and the associated Ricci tensor. The result is illustrated by a nontrivial application to a natural Hamiltonian defined on the 3-sphere.
The interface morphology of a spherical crystal in the undercooled melt affected by a far-field uniform flow
Authors: Chen M. W. , Wang Y. L. , Zhang H. , Wu L. Y. , Wang Z. D.
Published: May 2011

The effect of the convective flow caused by the far-field uniform flow on the interface morphology of a spherical crystal is studied by using the matched asymptotic expansion method. For the case that the far-field uniform flow is far less than the characteristic velocity of the interface, we obtain the uniformly valid asymptotic solution of the spherical crystal in the entire melt region. The analytical results show that the far-field uniform flow has significant effect on the interface morphology of the spherical crystal. The convection flow makes the interface of the growing spherical crystal enhance growth velocity in the upstream direction of the far-field uniform flow, inhibit growth in the downstream direction and decrease growth velocity on the two sides of the spherical crystal. The drag effect of the far-field uniform flow makes the interface morphology of the spherical crystal evolve into a pearlike oval shape. Our analytical result is consistent with the experimental and simulation results.
Analytical theory of bioheat transport
Authors: Fan Jing , Wang Liqiu
Published: May 2011

Macroscale thermal models for biological tissues can be developed either by the mixture theory of continuum mechanics or by the porous-media theory. Characterized by its simplicity, the former applies scaling-down from the global scale. The latter uses scaling-up from the microscale by the volume averaging, thus offers the connection between microscale and macroscale properties and is capable of describing the rich blood-tissue interaction in biological tissues. By using the porous-media approach, a general bioheat transport model is developed with the required closure provided. Both blood and tissue macroscale temperature fields are shown to satisfy the dual-phase-lagging (DPL) energy equations. Thermal waves and possible resonance may appear due to the coupled conduction between blood and tissue. For the DPL bioheat transport, contributions of the initial temperature distribution, the source term and the initial rate of change of temperature are shown to be inter-expressible under linear boundary conditions. This reveals the solution structure and considerably simplifies the development of solutions of the DPL bioheat equations. Effectiveness and features of the developed solution structure theorems are demonstrated via examining bioheat transport in skin tissue and during magnetic hyperthermia.
Electrical conduction and optical properties of doped silicon-on-insulator photonic crystals
Authors: Cardile Paolo , Franzò Giorgia , Lo Savio Roberto , Galli Matteo , Krauss Thomas F. , Priolo Francesco , O’ Faolain Liam
Published: May 2011

We investigate the electrical properties of silicon-on-insulator (SOI) photonic crystals as a function of both doping level and air filling factor. The resistance trends can be clearly explained by the presence of a depletion region around the sidewalls of the holes that is caused by band pinning at the surface. To understand the trade-off between the carrier transport and the optical losses due to free electrons in the doped SOI, we also measured the resonant modes of L3 photonic crystal nanocavities and found that surprisingly high doping levels, up to 1018/cm3, are acceptable for practical devices with Q factors as high as 4×104.
Calculus structure on the Lie conformal algebra complex and the variational complex
Authors: De Sole Alberto , Hekmati Pedram , Kac Victor G.
Published: May 2011

We construct a calculus structure on the Lie conformal algebra cochain complex. By restricting to degree one chains, we recover the structure of a \documentclass[12pt]{minimal}\begin{document}${\mathfrak g}$\end{document}g-complex introduced in [A. De Sole and V. G. Kac, Commun. Math. Phys. 292, 667 (2009)10.1007/s00220-009-0886-1]. A special case of this construction is the variational calculus, for which we provide explicit formulas.
Poisson–Boltzmann–Nernst–Planck model
Authors: Zheng Qiong , Wei Guo-Wei
Published: May 2011

The Poisson–Nernst–Planck (PNP) model is based on a mean-field approximation of ion interactions and continuum descriptions of concentration and electrostatic potential. It provides qualitative explanation and increasingly quantitative predictions of experimental measurements for the ion transport problems in many areas such as semiconductor devices, nanofluidic systems, and biological systems, despite many limitations. While the PNP model gives a good prediction of the ion transport phenomenon for chemical, physical, and biological systems, the number of equations to be solved and the number of diffusion coefficient profiles to be determined for the calculation directly depend on the number of ion species in the system, since each ion species corresponds to one Nernst–Planck equation and one position-dependent diffusion coefficient profile. In a complex system with multiple ion species, the PNP can be computationally expensive and parameter demanding, as experimental measurements of diffusion coefficient profiles are generally quite limited for most confined regions such as ion channels, nanostructures and nanopores. We propose an alternative model to reduce number of Nernst–Planck equations to be solved in complex chemical and biological systems with multiple ion species by substituting Nernst–Planck equations with Boltzmann distributions of ion concentrations. As such, we solve the coupled Poisson–Boltzmann and Nernst–Planck (PBNP) equations, instead of the PNP equations. The proposed PBNP equations are derived from a total energy functional by using the variational principle. We design a number of computational techniques, including the Dirichlet to Neumann mapping, the matched interface and boundary, and relaxation based iterative procedure, to ensure efficient solution of the proposed PBNP equations. Two protein molecules, cytochrome c551 and Gramicidin A, are employed to validate the proposed model under a wide range of bulk ion concentrations and external voltages. Extensive numerical experiments show that there is an excellent consistency between the results predicted from the present PBNP model and those obtained from the PNP model in terms of the electrostatic potentials, ion concentration profiles, and current–voltage (I–V) curves. The present PBNP model is further validated by a comparison with experimental measurements of I–V curves under various ion bulk concentrations. Numerical experiments indicate that the proposed PBNP model is more efficient than the original PNP model in terms of simulation time.
An integrated capacitance bridge for high-resolution, wide temperature range quantum capacitance measurements
Authors: Hazeghi Arash , Sulpizio Joseph A. , Diankov Georgi , Goldhaber-Gordon David , Wong H. S. Philip
Published: May 2011

We have developed a highly sensitive integrated capacitance bridge for quantum capacitance measurements. Our bridge, based on a GaAs HEMT amplifier, delivers attofarad (aF) resolution using a small AC excitation at or below kBT over a broad temperature range (4–300 K). We have achieved a resolution at room temperature of \documentclass[12pt]{minimal}\begin{document}$\mathrm{60\;aF}/\sqrt{\mathrm{Hz}}$\end{document}60 aF / Hz for a 10  mV ac excitation at 17.5 kHz, with an improved resolution at cryogenic temperatures, for the same excitation amplitude. We demonstrate the utility of our bridge for measuring the quantum capacitance of nanostructures by measuring the capacitance of top-gated graphene devices and cleanly resolving the density of states.
The angular velocity of a freely rotating sphere in a weakly viscoelastic matrix fluid
Authors: Housiadas Kostas D. , Tanner Roger I.
Published: May 2011

This letter reports on the angular velocity of a freely rotating rigid sphere in a weakly viscoelastic matrix fluid subject to simple shear flow imposed at infinity. The three-dimensional creeping flow around the sphere is assumed steady and isothermal. The solution for the angular velocity, which is derived here is the first available analytical result in the literature and is in accordance with the few existing experimental data and simulation results for non-Newtonian ambient fluids. We show that the rotation of the sphere is slower than in the Newtonian case, and that this phenomenon is at least a third-order fluid effect.
Effects of elemental distributions on the behavior of MgO-based magnetic tunnel junctions
Authors: Schreiber Daniel K. , Choi Young-suk , Liu Yuzi , Chiaramonti Ann N. , Seidman David N. , Petford-Long Amanda K.
Published: May 2011

Three-dimensional atom-probe tomography and transmission electron microscopy have been utilized to study the effects of Ta getter presputtering and either a Mg or Ru free-layer cap on the elemental distributions and properties of MgO-based magnetic tunnel junctions after annealing. Annealing the samples resulted in crystallization of the amorphous CoFeB layer and diffusion of the majority of the boron away from the crystallized CoFeB layers. The Ta getter presputter is found to reduce the segregation of boron at the MgO/CoFeB interface after annealing, improving the tunneling magnetoresistance of the tunnel junction. This effect is observed for samples with either a Ru free-layer cap or a Mg free-layer cap and is thought to be a result of a reduced oxygen concentration within the MgO due to the effect of Ta getter presputtering. A Ru free-layer cap provides superior magnetic and magnetotransport properties compared to a Mg free-layer cap. Mg from the Mg free-layer cap is observed to diffuse toward the MgO tunnel barrier upon annealing, degrading both the crystalline quality of the CoFeB and magnetic isolation of the CoFeB free-layer from the CoFeB reference-layer. Lateral variations in the B distribution within the CoFeB free-layer are observed in the samples with a Ru free-layer cap, which are associated with crystalline and amorphous grains. The B-rich, amorphous grains are found to be depleted in Fe, while the B-poor crystalline grains are slightly enriched in Fe.
Elimination mechanisms of Br2+ and Br+ in photodissociation of 1,1- and 1,2-dibromoethylenes using velocity imaging technique
Authors: Hua Linqiang , Lee Wei-Bin , Chao Meng-Hsuan , Zhang Bing , Lin King-Chuen
Published: May 2011

Elimination pathways of the Br2+ and Br+ ionic fragments in photodissociation of 1,2- and 1,1-dibromoethylenes (C2H2Br2) at 233 nm are investigated using time-of-flight mass spectrometer equipped with velocity ion imaging. The Br2+ fragments are verified not to stem from ionization of neutral Br2, that is a dissociation channel of dibromoethylenes reported previously. Instead, they are produced from dissociative ionization of dibromoethylene isomers. That is, C2H2Br2 is first ionized by absorbing two photons, followed by the dissociation scheme, C2H2Br2+ + hv→Br2+ + C2H2. 1,2-C2H2Br2 gives rise to a bright Br2+ image with anisotropy parameter of −0.5 ± 0.1; the fragment may recoil at an angle of ∼66° with respect to the C = C bond axis. However, this channel is relatively slow in 1,1-C2H2Br2 such that a weak Br2+ image is acquired with anisotropy parameter equal to zero, indicative of an isotropic recoil fragment distribution. It is more complicated to understand the formation mechanisms of Br+. Three routes are proposed for dissociation of 1,2-C2H2Br2, including (a) ionization of Br that is eliminated from C2H2Br2 by absorbing one photon, (b) dissociation from C2H2Br2+ by absorbing two more photons, and (c) dissociation of Br2+. Each pathway requires four photons to release one Br+, in contrast to the Br2+ formation that involves a three-photon process. As for 1,1-C2H2Br2, the first two pathways are the same, but the third one is too weak to be detected.
Two-dimensional streaming flows in high-intensity discharge lamps
Authors: Dreeben Thomas D. , Chini Gregory P.
Published: May 2011

High-intensity discharge (HID) lamps embody a practical application in which acoustically generated streaming flows are used to significantly improve energy efficiency. Streaming in these lamps is examined using finite-element simulations in conjunction with available experimental results on the basis of the assumption that the streaming motion is excited by two-dimensional acoustic standing waves. Neither the magnitude nor the direction of the time-averaged flows is adequately explained by existing theory. Consequently, a modified streaming analysis is proposed in which the fluctuating flow is driven by an oscillating pressure field rather by a moving boundary and convective terms in both the instantaneous and streaming flows are included. Density variations are also shown to be important to the generation of the observed and simulated streaming. This analysis highlights the differences between streaming flows in HID lamps and those described in canonical problems appearing elsewhere in the literature.
Molecular monolayers for conformal, nanoscale doping of InP nanopillar photovoltaics
Authors: Cho Kee , Ruebusch Daniel J. , Lee Min Hyung , Moon Jae Hyun , Ford Alexandra C. , Kapadia Rehan , Takei Kuniharu , Ergen Onur , Javey Ali
Published: May 2011

Semiconductor nanopillar arrays with radially doped junctions have been widely proposed as an attractive device architecture for cost effective and high efficiency solar cells. A challenge in the fabrication of three-dimensional nanopillar devices is the need for highly abrupt and conformal junctions along the radial axes. Here, a sulfur monolayer doping scheme is implemented to achieve conformal ultrashallow junctions with sub-10 nm depths and a high electrically active dopant concentration of 1019–1020 cm−3 in arrays of InP nanopillars. The enabled solar cells exhibit a respectable conversion efficiency of 8.1% and a short circuit current density of 25 mA/cm3. The work demonstrates the utility of well-established surface chemistry for fabrication of nonplanar junctions for complex devices.
Modeling and analysis of the spectral response for AlGaAs/GaAs HPTs for short wavelength optical communication
Authors: Khan Hassan A. , Rezazadeh Ali A. , Sohaib Sarmad
Published: May 2011

Detailed spectral response (SR) modeling for heterojunction bipolar phototransistors (HPTs) is presented in this work. All the related physical parameters are taken into account for the resolution of photogenerated excess minority carrier continuity equations in the active layers of the HPT. The layer dependence of the optical flux absorption profile at near-bandgap wavelengths is also investigated and its generalization as a single-exponential has been refuted for HPTs based on GaAs material systems (InGaP-GaAs/AlGaAs-GaAs). The variation in the responsivity of the device with changing base width is analyzed at various wavelengths and a detailed experimental setup for optical characterization of HPTs is also provided. The measured results at 635, 780, 808, and 850 nm show good agreement to the modeled data, validating the newly developed theoretical model.
Experimental study on electron field emission, Raman scattering, and low temperature electrical properties of nanocrystalline lead selenide thin films
Authors: Mukherjee Nillohit , Ahmed Sk. F. , Maji Swarup Kumar , Mondal Anup
Published: May 2011

We report the electron field emission properties, Raman scattering, and low (77 K) and room temperature electrical properties of nanocrystalline PbSe thin films. Structural characterizations (high resolution x-ray diffraction, atomic force microscopy, and high resolution transmission electron microscopy) revealed the formation of cubic PbSe with an average crystallite diameter of ca. 8 nm. Raman analysis showed a strong peak at 136 cm−1. Due to the nanocrystalline nature, the threshold field (5.5 V/μm) and approximate work function values were high, making the films a very efficient field emitter.
Numerical studies of transient gain reduction process in a multi-wire proportional chamber
Authors: Katagiri Ken , Furukawa Takuji , Noda Koji
Published: May 2011

A gain reduction process caused by successive beam irradiation in a multi-wire proportional chamber was numerically investigated to clarify the relations between the gas gain variation and the ion density distribution. A numerical code was developed based on a two-dimensional drift-diffusion model in order to evaluate the ion and electron density distributions and the electric field variation caused by the space charge effect. In order to consider the gain reduction process which occurs under the high rate and successive irradiation, the simulations were performed for the time period of ∼10–100 μs, which is much longer than the time required for ions to travel from an anode to a cathode. The numerical simulation results showed that for the low gas gain regime of ∼10, quasi-stationary density distribution of the ions was formed by the high-rate beams of ∼108 − 1010 particles per second, and that the transient variation of the gas gain became constant after establishment of the quasi-stationary ion density distributions.
Density-functional expansion methods: Generalization of the auxiliary basis
Authors: Giese Timothy J. , York Darrin M.
Published: May 2011

The formulation of density-functional expansion methods is extended to treat the second and higher-order terms involving the response density and spin densities with an arbitrary single-center auxiliary basis. The two-center atomic orbital products are represented by the auxiliary functions centered about those two atoms, and the mapping coefficients are determined from a local constrained variational procedure. This two-center variational procedure allows the mapping coefficients to be pretabulated and splined as a function of internuclear separation for efficient look up. The splines of mapping coefficients have a range no longer than that of the overlap integrals, and the auxiliary density appears as a single point-multipole expansion to all nonoverlapping atoms, thus allowing for the trivial implementation of a linear-scaling algorithm. The method is tested using Gaussian multipole expansions, and the effect of angular and radial completeness is explored. Several auxiliary basis sets are parametrized and compared to an auxiliary basis analogous to that used in the self-consistent-charge density-functional tight-binding model, and the method is demonstrated to greatly improve the representation of the density response with respect to a reference expansion model that does not use an auxiliary basis.
Structural, electronic, and magnetic properties of C-doped GaN nanoribbon
Authors: Zheng Fang-Ling , Zhang Yan , Zhang Jian-Min , Xu Ke-Wei
Published: May 2011

First-principles calculations are performed to study the structural, electronic, and magnetic properties of pure and C-doped GaN nanoribbon with both zigzag edge (ZGaNNR) and armchair edge (AGaNNR). With increasing ribbon width, both the indirect bandgap of ZGaNNR and the direct bandgap of AGaNNR decrease monotonically and become closer to each other approaching their asymptotic limit of a single layer of GaN sheet. One C atom substituting for one N atom causes a slight local expansion, while one C atom substituting for one Ga atom results in a large local contraction. Furthermore, the C atom is preferred to substitute for an edge N or Ga atom in either 6-ZGaNNR or 6-AGaNNR, especially edge Ga atoms in 6-AGaNNR. There exists about 0.65 µB magnetic moment, which arises mainly from doped C atom while a single N atom is substituted by one C atom in either 6-ZGaNNR or 6-AGaNNR, which may open a way to design magnetic nanodevices based on GaNNR.
The weakly bound states and resonances of the BeHe2 triatomic system
Authors: Han Hui-li , Li Yong , Shi Ting-yun
Published: May 2011

In the present study, we carry out a full search of the bound states and resonances of the He2Be triatomic system, with its isotopic variants 3He29Be, 3He4He9Be, and 4He29Be using the hyperspherical method. Three-body long-range effects are also included in the computation by adding to the additive potential the Axilrod-Teller triple-dipole term. In addition, the possibility of the occurrence of Efimov-type states in these systems is discussed. We have found a bound state for each of the 3He29Be and 3He4He9Be trimers, while one weakly bound excited state is also found to exist for the 4He29Be system.