bluuebunny/crossref_metadata_2025 huggingface dataset:
Survival and early recourse to care for dementia: A population based study
Authors: Pimouguet Clément , Delva Fleur , Le Goff Mélanie , Stern Yaakov , Pasquier Florence , Berr Claudine , Tzourio Christophe , Dartigues Jean‐François , Helmer Catherine
Published: August 2014

Background

A large proportion of dementia cases are still undiagnosed. Although early dementia care has been hypothesized to benefit both patients and families, evidence‐based benefits are lacking. Thus, investigating the benefits for newly demented persons according to their recourse to care in the “real life” appears critical.

Methods

We examined the relation between initial care recourse care and demented individuals' survival in a large cohort of incident dementia cases screened in a prospective population‐based cohort, the Three‐City Study. We assessed recourse to care for cognitive complaint at the early beginning of dementia when incident cases were screened. We classified patients in three categories: no care recourse, general practitioner consultation or specialist consultation. We used proportional hazard regression models to test the association between recourse to care and mortality, adjusting on socio‐demographical and clinical characteristics.

Results

Two hundred and fifty‐three incident dementia participants were screened at the 2 year or 4 year follow‐up. One third of the incident demented individuals had not consulted a physician for cognitive problems. Eighty‐six (34.0%) individuals had reported a cognitive problem only to their general practitioner (GP) and 80 (31.6%) had consulted a specialist. Mean duration of follow‐up after incident dementia was 5.1 years, during which 146 participants died. After adjustment on potential confounders, participants who had consulted a specialist early in the disease course presented a poorer survival than those who did not consult any physician (hazard ratio = 1.64, 95% confidence interval 1.03–2.62). There was a trend but no significant differential survival profile between participants who complained to their GP and those without any care recourse.

Conclusion

Neither recourse to a specialist nor recourse to GP improve survival of new dementia cases. Those who had consulted a specialist early in the disease course even reported a worse life expectancy than those who did not.
A presenilin 1 mutation in the first case of Alzheimer's disease: Revisited
Authors: Rupp Carsten , Beyreuther Konrad , Maurer Konrad , Kins Stefan
Published: August 2014

Background

Recently, a single point mutation in the presenilin 1 (PSEN1) gene of the first described Alzheimer's disease (AD) patient Auguste D was reported by Müller and co‐workers. However, the sequencing results of the DNA from a 100‐year‐old tissue contained some uncertainties.

Methods

We heat extracted DNA from an original histological slice of Auguste D's brain and used nested polymerase chain reaction for the amplification of different exons of genes known to be affected in familial forms of AD.

Results

Our sequencing analysis did not validate the reported mutation. Furthermore, an extended sequencing analysis of Auguste D's DNA revealed no indication of a nonsynonymous hetero‐ or homozygous mutation in the exons of APP, PSEN1, and PSEN2 genes comprising the already known familial AD mutations.

Conclusion

Despite the wealth of data from Müller and co‐workers, our results emphasize the requirement of more detailed analysis of Auguste D's DNA in future.
Patency Rates Among Heparin-Bonded and Conventional Polytetrafluoroethylene Grafts for Upper Extremity Hemodialysis Access
Authors: Cox Samantha R. , Moawad John A. , Marshall Lee Anne , Petrinec Drazen , McShannic Joseph R. , Steiner Richard , Fink John A.
Published: August 2014

Background: Although arteriovenous fistulae are the gold standard for vascular access, many patients do not have veins that are suitable for arteriovenous fistulae. These patients require arteriovenous grafts (AVGs). There have been no long-term trials designed to analyze the complication and patency rates of heparin-bonded versus conventional upper extremity AVGs. We aimed to compare patency and complication rates of upper extremity conventional versus heparin-bonded AVGs.

Methods: A retrospective chart review from 2008 through 2012 was conducted. Institutional review board approval was obtained. Patients with an upper extremity conventional or heparin-bonded AVG were included. Exclusion criteria included use of therapeutic anticoagulation and forearm loop grafts. Complication rates, reinterventions, and primary and secondary patency rates were compared using logistic regression analysis.

Results: The cohort consisted of 93 patients. Conventional and heparin-bonded grafts were compared and there was no statistically significant difference between the median time to use (29 vs 32 days; P =.440) or primary patency (P =.673). The duration of time elapsed until intervention was a median of 69 days (mean ±standard error =94.7 ± 10.4 days). Demographic characteristics of patients did not differ between the graft types (61% women; P =0.342). No statistically significant differences were seen between comorbidities in the 2 groups and body mass index did not differ (P =.986).

Conclusions: There is no improved primary patency, secondary patency, or difference in complication rates between patients who received conventional versus heparin-bonded AVGs.
Vein Port Access: YouTube as a Tool for Learning Vein Port Access Technique
Authors: Burbridge Brent , Stoneham Grant
Published: August 2014

Purpose: Vein port systems are often used for infusion therapy. Safe access of these devices is necessary to ensure optimal device performance and the minimization of possible complications. We assessed the utility of YouTube for learning vein port access technique.

Materials and methods: The YouTube video database was searched for video files demonstrating vein port access technique. A scoring tool was developed to acquire objective data about the adherence of the operator to accepted access technique.

Results: Fifty-one YouTube videos were assessed for their value for learning vein port access technique. Using a scoring tool with a maximum score of 36, the scores for the 51 videos ranged from 7 to 32 (mean score =18.7). The best scores were for videos recorded as instructional videos by nurses and patients, with scores ranging from 17 to 32 (mean score =24.0).

Conclusions: There was considerable variability in the utility and value of the videos reviewed. Some videos were very informative and instructional, some were very uninformative, and some conveyed incorrect information that could lead to device failure and undue complications related to inappropriate port access technique. Health care providers, patients, and other caregivers should be very skeptical of the value of YouTube videos demonstrating medical techniques and should only accept the information provided if it is from a reputable source, which can often be very difficult to ascertain.
Introduction: Exploring the Scope of the Australian Indigenous Studies Learning and Teaching Network
Authors: Barney Katelyn , Shannon Cindy , Nakata Martin
Published: August 2014

The Australian Indigenous Studies Learning and Teaching Network was established in 2011 to develop a focused national network of scholars to engage in key discussions about teaching Indigenous Studies at tertiary level. Funded by the Office for Learning and Teaching (2011–14), the Network combines leaders and early career academics and builds relationships between scholars in the discipline, identifies key issues and explores effective teaching and learning approaches. This introductory essay places this Special Issue of The Australian Journal of Indigenous Education (AJIE) in context by exploring the aims and outcomes of the Network along with the positioning of the Network team. It also examines key challenges for the Network and possible future directions.
Rethinking Majors in Australian Indigenous Studies
Authors: Nakata Martin , Nakata Vicky , Keech Sarah , Bolt Reuben
Published: August 2014

The challenges of finding more productive ways of teaching and learning in Australian Indigenous Studies have been a key focal point for the Australian Indigenous Studies Learning and Teaching Network. This article contributes to this discussion by drawing attention to new possibilities for teaching and learning practices amid the priority being given to the more practice-oriented educational approaches for future professionals and the cultural competencies of all students and staff. We explore courses sequenced as Indigenous Studies Majors and discuss two different conceptualisations for framing teaching and learning in Indigenous Studies courses — decolonising theory and cultural interface theory — and the implications for some of the teaching and learning practices they facilitate, including the positioning of students and the development of dispositions for future professional practice. We suggest that those academic teams who structure course sequences in Indigenous Studies have a role to play in experimenting with shifts in teaching and learning frameworks and the design of course sequences to encourage approaches that are more focused on developing students’ breadth and depth of knowledge of the field, as well as their capacities for deeper engagements with Indigenous thought and the scholarly disciplines.
Mapping More Than Aboriginal Studies: Pedagogy, Professional Practice and Knowledge
Authors: Norman Heidi
Published: August 2014

As undergraduate curriculum is increasingly required to meet a range of intellectual, professional practice and personal learning outcomes, what purpose does Australian Aboriginal Studies have in curriculum? Most Australian universities are currently in the process of developing institution-wide approaches to Indigenous Australian content in undergraduate curricula. One Australian university began this task by mapping how, where and why Indigenous perspectives, issues and content are included in undergraduate curriculum. This article reports on the findings of the mapping of Indigenous content and approaches to teaching at the University of Technology, Sydney (UTS) and thereby contributes to a strengths-based approach to understanding the purpose of Indigenous perspectives and issues in undergraduate curricula.
A U–Pb zircon age (479 ± 5 Ma) from the uppermost layers of the Ollo de Sapo Formation near Viveiro (NW Spain): implications for the duration of rifting-related Cambro-Ordovician volcanism in Iberia
Authors: LOPEZ-SANCHEZ M.A. , IRIONDO A. , MARCOS A. , MARTÍNEZ F.J.
Published: August 2014

The uppermost metavolcanic layer of the Cambro-Ordovician Ollo de Sapo Formation, the largest accumulation of pre-Variscan igneous rocks in the Iberian Peninsula, have been dated in its northernmost part using U–Pb SHRIMP-RG zircon age techniques at 479.0 ± 4.7 Ma. The age obtained is the youngest age found so far in the metavolcanic facies of Ollo de Sapo Formation and represents the cessation of the rifting-related Cambro-Ordovician Ollo de Sapo volcanism at the northernmost tip of the Iberian Peninsula. Our results show that the Cambro-Ordovician volcanism in the NW of the Iberian Peninsula is not as short-lived as previously thought and confirm the correlation between the Cambro-Ordovician volcanic sequences that crop out in the Central Iberian Zone and the French Southern Armorican Massif. Finally, our study suggests that the cessation of the Cambro-Ordovician volcanism along the Ibero-Armorican Arc was synchronic or, less probably, slightly diachronic with younger ages towards the north (in present-day geographical coordinates).
Survival rates and causes of mortality of leopards Panthera pardus in southern Africa
Authors: Swanepoel Lourens H. , Somers Michael J. , van Hoven Wouter , Schiess-Meier Monika , Owen Cailey , Snyman Andrei , Martins Quinton , Senekal Charl , Camacho Gerrie , Boshoff Willem , Dalerum Fredrik
Published: August 2014

Estimation of survival rates is important for developing and evaluating conservation options for large carnivores. However, telemetry studies for large carnivores are often characterized by small sample sizes that limit meaningful conclusions. We used data from 10 published and 8 unpublished studies of leopards Panthera pardus in southern Africa to estimate survival rates and investigate causes of leopard mortality. Mean survival rates were significantly lower in non-protected (0.55 ± SE 0.08) compared to protected areas (0.88 ± 0.03). Inside protected areas juveniles had significantly lower survival (0.39 ± 0.10) compared to subadults (0.86 ± 0.07) and adults (0.88 ± 0.04). There was a greater difference in cause of death between protected and non-protected areas for females compared to males, with people being the dominant cause of mortality outside protected areas for both females and males. We suggest there is cause for concern regarding the sustainability of leopard populations in South Africa, as high female mortality may have severe demographic effects and a large proportion of suitable leopard habitat lies in non-protected areas. However, because a large proportion of deaths outside protected areas were attributed to deliberate killing by people, we suggest that management interventions may have the potential to increase leopard survival dramatically. We therefore stress the urgency to initiate actions, such as conflict mitigation programmes, to increase leopard survival in non-protected areas.
Laser driven electron acceleration in a CNT embedded gas jet target
Authors: Kumar Ashok , Dahiya Deepak , Tripathi V. K.
Published: August 2014

The bubble regime acceleration of electrons by a short pulse laser in a carbon nanotube (CNT) embedded plasma is investigated, employing two-dimensional Particle-in-Cell simulations. The laser converts the CNT placed on the laser axis into dense plasma and expels the electrons out, to form a co-moving positive charged sheet inside the bubble. The additional field generated due to sheet enhances the energy of the monoenergetic bunch by about 5% and their number by 5–20%. For a typical 40 fs, 7.5 × 1019 Wcm−2 pulse in an underdense plasma of density n0, CNT of thickness 25 nm and electron density 30n0, produces a monoenergetic bunch of 115 MeV with 5% energy spread. When CNT density is raised to 90n0, the energy gain, energy spread and accelerated charge increases further. The analytical framework supports these features.
Mechanisms of level population in gas lasers pumped by ionizing radiation
Authors: Khasenov Mendykhan U.
Published: August 2014

The mechanisms of level population in high pressure gas lasers pumped by ionizing radiation at the 3p-3s transitions of neon, the d-p transitions of argon, krypton, xenon, and triplet lines of mercury are analyzed. It is shown that dissociative recombination of molecular ions with electrons is not the basic process responsible for populating the p levels of inert gas atoms. It is assumed that the most likely channel for d-level population is direct excitation of atoms by secondary electrons and excitation transfer from buffer gas atoms, with p levels being populated by transitions from upper levels. Dissociative recombination of mercury molecular ions with electrons is the basic process responsible for populating the 73S1 level of mercury atoms.
Impact of melt segregation on tonalite-trondhjemite-granodiorite (TTG) petrogenesis
Authors: Rushmer Tracy , Jackson Matt
Published: August 2014

“In searching for the origin of granites, it is tempting to view them as purely chemical systems”

(Pitcher 1979, p. 90)

Although sophisticated geochemical studies tell us that tonolite-trondhjemite-granodiorite (TTG) plutonic complexes must be formed by partial melting of metabasaltic source material, they cannot tell us the tectonic regime in which this crust was formed, nor how large volumes of TTG magma can be generated. This study suggests that a solution to TTG arc crust formation requires a strongly interdisciplinary approach, to resolve the tectonic setting (slab melt verses mafic lowermost crust sources), the time and length scales for melting and extraction, and the role of melt segregation mechanisms in the formation of both Archean TTGs and more recent adakite-like magmas. The aim of this paper is to present an experimental approach which, when coupled with numerical models, allows some of these issues to be addressed. The experiments are designed to reproduce the local changes in bulk composition that are predicted to occur in response to buoyancy-driven melt segregation along grain edges and associated compaction of the solid residue. The preliminary study presented here documents the changes we observe in the melt composition and melt and solid phase modes between earlier direct partial melting and the new segregation equilibration experiments on metabasalt bulk compositions. The results suggest that if dynamic melt segregation and equilibrium processes are active, they may modify the normally robust geochemical indicators, such as Mg-numbers, which are typically used to develop models of TTG petrogenesis.
Clinical features and treatment outcome in newly diagnosed Chinese patients with multiple myeloma: results of a multicenter analysis
Authors: Lu J , Lu J , Chen W , Huo Y , Huang X , Hou J ,   the Chinese Medical Doctor Association Hematology Branch
Published: August 2014

The aim of this study was to understand the clinical features and treatment outcome of Chinese patients with multiple myeloma (MM). This retrospective study enrolled 940 newly diagnosed inpatients (median age, 59 years; immunoglobulin (Ig)D isotype, 6.5%) with complete follow-up data at three centers. In all, 85.8% of patients were of Durie-Salmon stage III and 48.3% were of International Staging System (ISS) stage III at diagnosis. Also, 9.6% of patients had extramedullary plasmacytoma. Compared with IgG, IgD-type patients were diagnosed at a younger age, and more patients were of ISS stage III, with hypercalcemia, elevated levels of lactate dehydrogenase, hyperuricemia, renal dysfunction and 1q21 amplification (P=0.03). The overall survival (OS) benefit was more prominent in IgG than in IgD when patients received bortezomib; however, they showed no significant difference when they received older therapies such as melphalan combined with prednisone or vincristine combined with adriamycin and dexamethasone. Fluorescence in situ hybridization (FISH) results showed that 17.6% had 17p13 deletion. Conventional cytogenetics revealed that 13.3% were hypodiploid and those cases had the worst survival, but hyperdiploid cases (9.3%) did not show any survival benefit compared with those with a normal karyotype (77.4%). Median OS and progression-free survival for all patients were 54 and 26 months, respectively. Significant factors for survival by multivariate analysis were gender, ISS stage, number of FISH abnormalities and extramedullary disease. MM in mainland China presents with different features, with patients being of younger age and having higher risk and more survival benefit in IgG patients receiving bortezomib.
The influence of N-fertilization regimes on N2O emissions and denitrification in rain-fed cropland during the rainy season
Authors: Dong Zhixin , Zhu Bo , Zeng Zebin
Published: August 2014

Crop residue combined with synthetic fertilizer is recommended as an optimal strategy for mitigating N2O emissions and denitrification-induced N loss.
Tissue-culture light sheet fluorescence microscopy (TC-LSFM) allows long-term imaging of three-dimensional cell cultures under controlled conditions
Authors: Pampaloni Francesco , Berge Ulrich , Marmaras Anastasios , Horvath Peter , Kroschewski Ruth , Stelzer Ernst H. K.
Published: August 2014

This novel system for the long-term fluorescence imaging of live three-dimensional cultures provides minimal photodamage, control of temperature, CO2, pH, and media flow.
A high-performance Pt–Co bimetallic catalyst with polyethyleneimine decorated graphene oxide as support for hydrolysis of ammonia borane
Authors: Li Mengxiong , Hu Jiantong , Chen Zhongxin , Lu Hongbin
Published: August 2014

PEI–GO/Pt0.17Co0.83was synthesized and showed the best catalytic activity of the reported Pt-based bimetallic catalysts for the hydrolysis of ammonia borane.
Influence of surfactant alkyl length in functionalizing sol–gel derived microporous cobalt oxide silica
Authors: Olguin Gianni , Yacou Christelle , Smart Simon , Diniz da Costa João C.
Published: August 2014

The size or alkyl chain length of cationic surfactants can be used to tailor both the pore morphology and the functionality or oxidation state of cobalt in silica materials.
Tuning of the freezing and melting points of [Hmim][NO3] by the addition of water and nitrate salts
Authors: Di Francesco Fabio , Ferrari Carlo , Moni Letizia , Melai Bernardo , Bernazzani Luca , Chiappe Cinzia
Published: August 2014

Simple chemometric models can be used to describe properties of ionic liquids.
Electronic infrared light absorption of a tri-palladium complex containing two π-expanded tetracene ligands
Authors: Suzuki Tsuyoshi , Nakagawa Takafumi , Ohkubo Kei , Fukuzumi Shunichi , Matsuo Yutaka
Published: August 2014

Three palladium atoms connect two π-expanded tetracene ligands to extend π-conjugation, realizing low energy absorption in the infrared region.
Hyaluronic acid/poly-l-lysine bilayered silica nanoparticles enhance the osteogenic differentiation of human mesenchymal stem cells
Authors: Amorim Sara , Martins Albino , Neves Nuno M. , Reis Rui L. , Pires Ricardo A.
Published: August 2014

The coating of silica nanoparticles with a bilayer of poly-l-lysine and hyaluronic acid enhances the osteogenic differentiation of human bone marrow stem cells at low nanoparticle concentrations (25 μg mL−1 and 12.5 μg mL−1).
Stimuli-responsive metallo-supramolecular polymer films: design, synthesis and device fabrication
Authors: Higuchi Masayoshi
Published: August 2014

Based on the metal–ligand or metal–metal interactions, metallo-supramolecular polymer films showed stimuli-responsive electro- and photo-chemical properties such as electrochromism.
Maximizing the rigidity of a large planar orifice air bearing
Authors: Mullen Michael , Broadhurst John
Published: August 2014

A rotating support for a large astronomical mirror has been implemented using an opposed surface planar orifice air bearing. This bearing needs to provide rotation as free as possible of static and dynamic friction, as well as maximizing the resistance to sudden angular deviations produced by wind gusts. Information on the design of traditional bearings, namely, a cavity supplied with air under pressure through an orifice or diffuser flow restriction and closed by the moving member, has been published in detail. These traditional bearings are not suitable for the application described, due to their slow speed of response to transient changes in forces, a considerable volume of air being needed to change the pressure in the cavity. The air bearing used in this application has no cavity but consists of two flat surfaces in close proximity with air under pressure introduced at the center of one of the surfaces. The volume of air in the bearing is therefore minimized, improving the response to load change transients. The load capacity of this type bearing is reduced as the air between the bearing surfaces is not at constant pressure, but is expanding from the center point of injection to its escape at the edges. This paper indicates a quantitative method of determining the size of the air supply orifices to achieve the maximum rigidity orthogonal to the direction of motion. The approach described can also be applied to optimizing the geometry of other non-cavity air bearings.
The cyclopropene radical cation: Rovibrational level structure at low energies from high-resolution photoelectron spectra
Authors: Vasilatou K. , Michaud J. M. , Baykusheva D. , Grassi G. , Merkt F.
Published: August 2014

The cyclopropene radical cation (c-C3\documentclass[12pt]{minimal}\begin{document}${\rm H}_4^+$\end{document}H4+) is an important but poorly characterized three-membered-ring hydrocarbon. We report on a measurement of the high-resolution photoelectron and photoionization spectra of cyclopropene and several deuterated isotopomers, from which we have determined the rovibrational energy level structure of the \documentclass[12pt]{minimal}\begin{document}$\widetilde{\rm X}^+$\end{document}X̃+ 2B2 ground electronic state of c-C3\documentclass[12pt]{minimal}\begin{document}${\rm H}_4^+$\end{document}H4+ at low energies for the first time. The synthesis of the partially deuterated isotopomers always resulted in mixtures of several isotopomers, differing in their number of D atoms and in the location of these atoms, so that the photoelectron spectra of deuterated samples are superpositions of the spectra of several isotopomers. The rotationally resolved spectra indicate a C2v-symmetric R0 structure for the ground electronic state of c-C3\documentclass[12pt]{minimal}\begin{document}${\rm H}_4^+$\end{document}H4+. Two vibrational modes of c-C3\documentclass[12pt]{minimal}\begin{document}${\rm H}_4^+$\end{document}H4+ are found to have vibrational wave numbers below 300 cm−1, which is surprising for such a small cyclic hydrocarbon. The analysis of the isotopic shifts of the vibrational levels enabled the assignment of the lowest-frequency mode (fundamental wave number of ≈110 cm−1 in c-C3\documentclass[12pt]{minimal}\begin{document}${\rm H}_4^+$\end{document}H4+) to the CH2 torsional mode (\documentclass[12pt]{minimal}\begin{document}$\nu _8^+$\end{document}ν8+, A2 symmetry) and of the second-lowest-frequency mode (≈210 cm−1 in c-C3\documentclass[12pt]{minimal}\begin{document}${\rm H}_4^+$\end{document}H4+) to a mode combining a CH out-of-plane with a CH2 rocking motion (\documentclass[12pt]{minimal}\begin{document}$\nu _{15}^+$\end{document}ν15+, B2 symmetry). The potential energy along the CH2 torsional coordinate is flat near the equilibrium structure and leads to a pronounced anharmonicity.
Theoretical predictions of properties and volatility of chlorides and oxychlorides of group-4 elements. I. Electronic structures and properties of MCl4 and MOCl2 (M = Ti, Zr, Hf, and Rf)
Authors: Pershina V. , Borschevsky A. , Iliaš M.
Published: August 2014

Relativistic, infinite order exact two-component, density functional theory electronic structure calculations were performed for MCl4 and MOCl2 of group-4 elements Ti, Zr, Hf, and element 104, Rf, with the aim to predict their behaviour in gas-phase chromatography experiments. RfCl4 and RfOCl2 were shown to be less stable than their lighter homologs in the group, tetrachlorides and oxychlorides of Zr and Hf, respectively. The oxychlorides turned out to be stable as a bent structure, though the stabilization energy with respect to the flat one (C2v) is very small. The trend in the formation of the tetrachlorides from the oxychlorides in group 4 is shown to be Zr < Hf < Rf, while the one in the formation of the oxychlorides from the chlorides is opposite. All the calculated properties are used to estimate adsorption energy of these species on various surfaces in order to interpret results of gas-phase chromatography experiments, as is shown in Paper II.
Universal scaling of potential energy functions describing intermolecular interactions. I. Foundations and scalable forms of new generalized Mie, Lennard-Jones, Morse, and Buckingham exponential-6 potentials
Authors: Xantheas Sotiris S. , Werhahn Jasper C.
Published: August 2014

Based on the formulation of the analytical expression of the potential V(r) describing intermolecular interactions in terms of the dimensionless variables r* = r/rm and ɛ* = V/ɛ, where rm is the separation at the minimum and ɛ the well depth, we propose more generalized scalable forms for the commonly used Mie, Lennard-Jones, Morse, and Buckingham exponential-6 potential energy functions. These new generalized forms have an additional parameter from the original forms and revert to the original ones for some choice of that parameter. In this respect, the original forms of those potentials can be considered as special cases of the more general forms that are introduced. We also propose a scalable, non-revertible to the original one, 4-parameter extended Morse potential.
Optimizing biased semiconductor superlattices for terahertz amplification
Authors: Lei Xiaoli , Wang Dawei , Wu Zhaoxin , Dignam M. M.
Published: August 2014

Over the past 15 yr or more, researchers have been trying to achieve gain for electromagnetic fields in the terahertz frequency region using biased semiconductor superlattices, but with little success. In this work, we employ our model of the excitonic states in biased GaAs/Al0.3Ga0.7As semiconductor superlattices to find the optimal structures for amplification of terahertz radiation. In particular, we determine the optimum well width, barrier width, and bias field for terahertz fields with frequencies ranging from 1 to 4 terahertz. We find that gain coefficients on the order of 40 cm−1 should be achievable over most of this frequency range.
Perfect electrical switching of edge channel transport in HgTe quantum wells controlled by gate voltage
Authors: Fu Hua-Hua , Wu Dan-Dan , Gu Lei
Published: August 2014

We present a proposal to realize a perfect electrical switching of topological edge-state transport in a HgTe quantum well (QW). In our device design, we place a strip-like top gate voltage in a conventional quantum-point-contact (QPC) region in the HgTe QW. The numerical calculations show that upon increasing the gate voltage, two new conductance channels are developed in the transport direction and just neighbouring the boundaries of the top gate. The quantum states in the new channels can couple with the edge states to open a gap in energy spectrum, and in turn the gap width can be adjusted by the gate voltage, indicating that switch-on/off of the edge channels can be manipulated in a controllable way. Our device can not only be considered as a development of the conventional QPC structure based on the HgTe QW but also provides a new route to realize topological electrical switchers.
Overall current-voltage characteristics of space charge controlled currents for thin films by a single carrier species
Authors: Seki Kazuhiko
Published: August 2014

The Mott-Gurney equation (Child's law) has been frequently applied to measure the mobility of carrier transport layers. One of the main assumption in the Mott-Gurney theory is ignoring the diffusive currents. It was not obvious, however, whether the diffusive currents can be ignored for thin carrier transport layers. We obtained the current-voltage relation using analytical solutions of drift-diffusion equation coupled with the Poisson's equation. The integration constants were numerically determined using nonlinear equations obtained from boundary conditions. A simple analytical relation between the voltage and current was also derived. The analytical equation improved over the Mott-Gurney equation when the voltage is between 0.1 and 2 (V) at room temperature. By using published data, we show that both the mobility and the layer thickness can be simultaneously obtained by applying the analytical expression. The effect of diffusion on the current-voltage relation is explained by the movement of the virtual electrode formed by space charge accumulation.
Theoretical comparison of multiple quantum wells and thick-layer designs in InGaN/GaN solar cells
Authors: Cavassilas Nicolas , Michelini Fabienne , Bescond Marc
Published: August 2014

This theoretical work analyzes the photovoltaic effect in non-polar InGaN/GaN solar cells. Our electronic transport model considers quantum behaviors related to confinement, tunneling, electron-phonon, and electron-photon scatterings. Based on this model, we compare a multiple quantum wells cell with its thick-layer counterpart. We show that the structure of multiple quantum wells is a promising design providing better compromise between photon-absorption and electronic transport. This balance is necessary since these two phenomena are shown to be antagonist in nanostructure based solar cells. In these devices, we also show that phonon absorption increases the short-circuit current, while phonon emission reduces the open-circuit voltage.
Optimization of double-layer graphene plasmonic waveguides
Authors: Lin I.-Tan , Liu Jia-Ming
Published: August 2014

Optimization of waveguides based on surface plasmons in double-layer graphene (DLG) is presented. In contrast to previous treatments, the effects of both extrinsic scattering and intrinsic Landau damping are simultaneously considered in this analysis. We show that an optimum frequency and an optimum spacing between two graphene sheets can be found to minimize the attenuation of the plasmon propagation. The optical mode is found to be less lossy than the acoustic mode below a certain frequency, but above this frequency the situation is reversed. All observable features of DLG are corroborated by analytical or numerical results, shedding light on the possibility of compact and tunable DLG-based plasmonic waveguides.
Asymmetric multiscale detrended cross-correlation analysis of financial time series
Authors: Yin Yi , Shang Pengjian
Published: August 2014

We propose the asymmetric multiscale detrended cross-correlation analysis (MS-ADCCA) method and apply MS-ADCCA method to explore the existence of asymmetric cross-correlation for daily price returns in US and Chinese stock markets and to assess the properties of these asymmetric cross-correlations. The results all show the existences of asymmetric cross-correlations, while small asymmetries at small scales and larger asymmetries at larger scales are also displayed. There is a strong similarity between S&P500 and DJI, and we reveal that the asymmetries depend more on the cross-correlations of S&P500 vs. DJI, S&P500 vs. NQCI, DJI vs. NQCI, and ShangZheng vs. ShenCheng when the market is falling than rising, respectively. By comparing the spectra of S&P500 vs. NQCI and DJI vs. NQCI with uptrends and downtrends, we detect some new characteristics which lead to some new conclusions. Likewise, some new conclusions also can be drawn by the new characteristics displayed through the comparison between the spectra of ShangZheng vs. HSI and ShenCheng vs. HSI. Obviously, we conclude that although the overall spectra are similar and one market has the same effect when it is rising and falling in the study of asymmetric cross-correlations between it and different markets, the cross-correlations and asymmetries on the trends of the different markets are all different. MS-ADCCA method can detect the differences on the asymmetric cross-correlations by different trends of markets. Moreover, the uniqueness of cross-correlation between NQCI and HSI can be detected in the study of the asymmetric cross-correlations, which confirms that HSI is unique in the Chinese stock markets and NQCI is unique in the US stock markets further.
Drug-resistant tuberculosis.
Authors: Kwaghe A. V. , Ameh J. A. , Ambali A. G. , Kudi C. , Kwaghe V. G.
Published: August 2014

Drug-resistant tuberculosis (TB) is a challenge in the treatment and eradication of TB worldwide. Over the years, resistance to the treatment of TB emerged as a result of poor management of the disease. The benefits of rapid diagnosis for TB and drug resistance in patients are enormous, particularly with regard to increased chances of the patients' survival and decrease in the possible spread and acquisition of drug-resistant TB. This review highlights the mutational genes responsible for resistance for each of the drugs and the various methods used in detecting drug-resistant TB. This review shed more light on the available techniques, their merits and demerits. Studies have shown advancement in this area but the high cost of using molecular techniques, which provides timely results in the detecting of multi-drug-resistant TB and extensively drug-resistant TB still poses challenges for developing countries. Unfortunately, it can take months to detect TB and drug-resistant TB using the conventional methods which is quite cumbersome and poses a risk to both the patient and the public due to delay in appropriate commencement of treatment. Also, the use of endorsed liquid culture medium such as the microscopic-observation drug and nitrate reductase assay is still a challenge to developing nations. A lot has been done in the treatment and diagnosis of drug-resistant TB but more needs to be done especially in the developing countries in order to curtail the menace of drug-resistant TB.
Dense flag triangulations of 3-manifolds via extremal graph theory
Authors: Adamaszek Michał , Hladký Jan
Published: August 2014

We characterize

f
f

-vectors of sufficiently large three-dimensional flag Gorenstein

∗

^*

complexes, essentially confirming a conjecture of Gal [Discrete Comput. Geom., 34 (2), 269–284, 2005]. In particular, this characterizes

f
f

-vectors of large flag triangulations of the

3
3

-sphere. Actually, our main result is more general and describes the structure of closed flag 3-manifolds which have many edges.

Looking at the 1-skeleta of these manifolds we reduce the problem to a certain question in extremal graph theory. We then resolve this question by employing the Supersaturation Theorem of Erdős and Simonovits.
Cross-validation under separate sampling: strong bias and how to correct it
Authors: Braga-Neto Ulisses M. , Zollanvari Amin , Dougherty Edward R.
Published: August 2014

Motivation: It is commonly assumed in pattern recognition that cross-validation error estimation is ‘almost unbiased’ as long as the number of folds is not too small. While this is true for random sampling, it is not true with separate sampling, where the populations are independently sampled, which is a common situation in bioinformatics.

Results: We demonstrate, via analytical and numerical methods, that classical cross-validation can have strong bias under separate sampling, depending on the difference between the sampling ratios and the true population probabilities. We propose a new separate-sampling cross-validation error estimator, and prove that it satisfies an ‘almost unbiased’ theorem similar to that of random-sampling cross-validation. We present two case studies with previously published data, which show that the results can change drastically if the correct form of cross-validation is used.

Availability and implementation: The source code in C++, along with the Supplementary Materials, is available at: http://gsp.tamu.edu/Publications/supplementary/zollanvari13/.

Contact: ulisses@ece.tamu.edu

Supplementary information:  Supplementary data are available at Bioinformatics online.
SCDFinder, a Web-based tool for the identification of putative novel ATM and ATR targets
Authors: Cara Lukas , Baitemirova Medina , Duong Franklin , Larios-Sanz Maia , Ribes-Zamora Albert
Published: August 2014

Motivation: The S/TQ cluster domain (SCD) constitutes a new type of protein domain that is not defined by sequence similarity but by the presence of multiple S/TQ motifs within a variable stretch of amino acids. SCDs are recognized targets for DNA damage response (DDR) kinases like ATM and ATR. Characterizing DDR targets is of significant interest. The aim of this work was to develop a web-based tool to allow for easy identification and visualization of SCDs within specific proteins or in whole proteome sets, a feature not supported by current domain and motif search tools.

Results: We have developed an algorithm that (i) generates a list of all proteins in an organism containing at least one user-defined SCD within their sequence, or (ii) identifies and renders a visual representation of all user-defined SCDs present in a single sequence or batch of sequences.

Availability and implementation: The application was developed using Pearl and Python, and is available at the following URL: http://ustbioinfo.webfactional.com/scd/.

Contact:  ribesza@stthom.edu or lariosm@stthom.edu
Gastroesophageal Reflux Disease
Authors: Murray Joseph A.
Published: August 2014

Gastroesophageal reflux is the reflux of gastric contents other than air into or through the esophagus. Gastroesophageal reflux disease (GERD) refers to reflux that produces frequent symptoms or results in damage to the esophageal mucosa or contiguous organs of the upper aerodigestive system and occasionally the lower respiratory tract. Etiology, contributing factors, presentation, symptoms (heartburn and acid regurgitation), diagnosis, and treatment of the disease (including histamine receptor blockers, proton pump inhibitors, prokinetics, and procedural treatments) are addressed.
Viral Hepatitis
Authors: Poterucha John J.
Published: August 2014

Viral infections are important causes of liver disease worldwide. The five primary hepatitis viruses that have been identified are A, B, C, D (or delta), and E. Other viruses such as cytomegalovirus and Epstein-Barr virus also can result in hepatitis as part of a systemic infection. It is useful to divide hepatitis syndromes into acute and chronic forms. Acute hepatitis can last from weeks up to 6 months and is often accompanied by jaundice. Symptoms of acute hepatitis tend to be similar regardless of cause and include anorexia, malaise, dark urine, fever, and mild abdominal pain. In chronic hepatitis, patients are often asymptomatic but may complain of fatigue. Each hepatitis virus causes acute hepatitis, but only hepatitis B, C, and D viruses can cause chronic hepatitis. The purpose of this chapter is to review the primary hepatitis viruses. A more comprehensive discussion of acute hepatitis is found in other chapters.
Portal Hypertension–Related Bleeding
Authors: Sanchez William , Kamath Patrick S.
Published: August 2014

Portal hypertensive bleeding encompasses a spectrum of conditions that include esophageal, gastric, and ectopic varices and portal hypertensive gastrointestinal enteropathy. Esophageal variceal hemorrhage occurs through a combination of increased portal pressure and local factors within the varix itself. Management of esophageal varices includes primary prophylaxis of variceal hemorrhage, treatment of actively bleeding varices, and prevention of variceal rebleeding (secondary prophylaxis). The choice of therapy for primary prophylaxis depends on patient preferences and includes pharmacologic therapy with ?-blockers or variceal band ligation, especially if ?-blocker therapy fails or the therapy is not tolerated by the patient. Active bleeding is best treated endoscopically. A combination of pharmacologic and endoscopic therapy is preferred for secondary prophylaxis. Surgical shunts or transjugular intrahepatic portosystemic shunts (TIPSs) are second-line therapy.
Metabolic Liver Disease
Authors: Sanchez William
Published: August 2014

Metabolic liver disease refers to inherited disorders of metabolism that manifest prominently with liver disease. The three major inherited disorders that cause liver disease in adults include alpha1-antitrypsin deficiency, Wilson disease, and hereditary hemochromatosis. All are multisystem disorders that cause liver injury by various mechanisms but which can ultimately lead to cirrhosis and complications of liver failure. Also, various inborn errors of metabolism cause liver disease that manifests during childhood. These inborn errors of metabolism are, in aggregate, a major indication for pediatric liver transplantation. As an increasing number of patients with childhood syndromes with liver involvement survive into adulthood, adult gastroenterologists will need to become familiar with their care.
Nonalcoholic Fatty Liver Disease
Authors: Watt Kymberly D.
Published: August 2014

Nonalcoholic fatty liver disease (NAFLD) refers to the accumulation of fat (mainly triglycerides) in hepatocytes that result from insulin resistance. NAFLD is recognized as the most common chronic liver disease in the Western world. NAFLD encompasses a wide spectrum of disease from bland hepatic steatosis, which is generally benign, to nonalcoholic steatohepatitis (NASH), which may progress to cirrhosis, liver failure, and hepatocellular carcinoma. Hence, distinguishing between hepatic steatosis and NASH has important prognostic and management implications.
Gallstones
Authors: Gleeson Ferga C.
Published: August 2014

The prevalence of gallstones varies widely and is as high as 60% to 70% among American Indians and 10% to 15% among white adults of developed countries. In the United States, gallstone disease is one of the most common and costly digestive diseases that requires hospitalization. The estimated annual direct cost is $6.2 billion. It is newly diagnosed in more than 1 million people annually, and approximately 700,000 cholecystectomies are performed each year. Therefore, an understanding of the anatomy and physiology, clinical presentation, and efficient approaches to investigations and management of gallstone disease are important. Optimal clinical management varies considerably, depending on the presentation.
Gastrointestinal Manifestations of Systemic Disease
Authors: Sweetser Seth R.
Published: August 2014

Many systemic disorders can have gastrointestinal manifestations. This chapter is an overview of these diseases as they affect the gastrointestinal tract and liver, with emphasis on disorders not considered elsewhere in this book. Gastrointestinal symptoms that can point to systemic disease are rapid weight loss or gain, nausea, vomiting, diarrhea, constipation, abdominal pain, jaundice, and abnormal results of liver function tests. Various gastrointestinal symptoms can be signs of dermatologic, immunologic, cardiovascular, pulmonary, renal, endocrine, hematologic, oncologic, neuromuscular, and rheumatologic disease. Pregnancy and gynecologic conditions may also have gastroenterologic manifestations.
Using Self‐Reported Health Measures to Predict High‐Need Cases among Medicaid‐Eligible Adults
Authors: Wherry Laura R. , Burns Marguerite E. , Leininger Lindsey Jeanne
Published: August 2014

Objective

To assess the ability of different self‐reported health (SRH) measures to prospectively identify individuals with high future health care needs among adults eligible for Medicaid.

Data Sources

The 1997–2008 rounds of the National Health Interview Survey linked to the 1998–2009 rounds of the Medical Expenditure Panel Survey (n = 6,725).

Study Design

Multivariate logistic regression models are fitted for the following outcomes: having an inpatient visit; membership in the top decile of emergency room utilization; and membership in the top cost decile. We examine the incremental predictive ability of six different SRH domains (health conditions, mental health, access to care, health behaviors, health‐related quality of life [HRQOL], and prior utilization) over a baseline model with sociodemographic characteristics. Models are evaluated using the c‐statistic, integrated discrimination improvement, sensitivity, specificity, and predictive values.

Principal Findings

Self‐reports of prior utilization provide the greatest predictive improvement, followed by information on health conditions and HRQOL. Models including these three domains meet the standard threshold of acceptability (c‐statistics range from 0.703 to 0.751).

Conclusions

SRH measures provide a promising way to prospectively profile Medicaid‐eligible adults by likely health care needs.