bluuebunny/crossref_metadata_2025_split huggingface dataset:
Size‐tuneable synthesis of photoconducting poly‐(3‐hexylthiophene) nanofibres and nanocomposites
Authors: Zhao Yichen , Sugunan Abhilash , Rihtnesberg David B. , Wang Qin , Toprak Muhammet S. , Muhammed Mamoun 
Published: May 2012

AbstractPoly‐(3‐hexylthiophene) (P3HT) has been applied in many fields such as organic solar cells, printed electronic circuits, due to superior semiconducting properties compared to other semiconducting polymers. The presence of π–π interaction causes regio‐regular P3HT to form ordered lamellar stacks during crystallisation. Here we report a simple room temperature, solution based method to synthesise P3HT nanofibres with controllable sizes. Our method is based on differing solubility of P3HT in various solvents. In a mixed solvent environment, we could control the precipitation of P3HT to obtain nanofibres with various diameters by varying the ratios of the solvents. We found that the lengths of the nanofibres could be controlled with concentration of the solution. Other methods to obtain nanofibres of P3HT invariably involves heating and controlled cooling which makes reproducibility and morphology control difficult. Furthermore, we synthesised a nanocomposite consisting of P3HT nanofibres and quasi‐type‐II quantum dots and evaluated the photoelectric properties of the nanofibres as well as the nanocomposites using interdigitated gold microelectrodes (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultrafast photoconductors from low‐temperature‐grown GaAs for terahertz components activated by femtosecond 1‐μm wavelength laser pulses
Authors: Adamonis Juozas , Bertulis Klemensas , Bičiūnas Andrius , Adomavičius Ramūnas , Krotkus Arūnas 
Published: May 2012

AbstractTerahertz time‐domain spectroscopy (TDS) system based on femtosecond Yb:KGW laser, photoconductive emitters and detectors made using low‐temperature‐grown (LTG) GaAs layers annealed at moderate temperatures (∼400 °C) was demonstrated. Measured photoexcited charge carriers concentration of these layers increased lineary with an optical power, showing that the transitions from defect band to conduction band are dominant. The largest amplitude THz pulse was emitted by the device made from the LTG‐GaAs layer annealed at 420 °C temperature with useful signal bandwidth reaching 3 THz. On the other hand, detectors made from this material were more than an order of magnitude less sensitive than conventional GaBiAs detectors (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural and optical optimization of ZnSe‐based laser heterostructures with graded index waveguide
Authors: Gronin S. V. , Sedova I. V. , Sorokin S. V. , Klimko G. V. , Belyaev K. G. , Lebedev A. V. , Sitnikova A. A. , Toropov A. A. , Ivanov S. V. 
Published: May 2012

AbstractWe report on structural and photoluminescence (PL) studies of wide gap II‐VI laser heterostructures involving the graded index waveguide (GIW) based on short period Zn(Mg)SSe/ZnSe superlattices (SLs) and the active region comprising single or multiple electronically‐coupled CdSe/ZnSe QD sheets. Precise compensation of elastic stresses in the SL waveguide and optimization of the ZnSe/GaAs initial growth stage have resulted in good crystalline quality of the laser structures and reduction of the extended defect density down to 104 cm‐2. Express monitoring of the defect density by using the photoluminescence microscope was supported by transmission electron microscopy studies. PL data have demonstrated efficient transport of nonequilibrium carriers through the GIW SLs to the active region (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Raman spectra and emission of CdSe/ZnS quantum dots bioconjugated to OC125 antibodies
Authors: Quintos‐Vazquez A. L. , Vega‐Macotela L. G. , Torchynska T. V. , Shcherbyna L. 
Published: May 2012

AbstractThis paper presents the analysis of photoluminescence (PL) and Raman scattering spectra of CdSe/ZnS quantum dots (QDs) covered by the amine (NH2)‐derivatized PEG polymer nonconjugated and bioconjugated to ovarian cancer (OC 125) antibodies and localized on the Si substrate. Commercial CdSe/ZnS QDs used are characterized by the color emission with the maxima at 525 nm (2.36 eV) and 605 nm (2.05 eV) at 300 K. PL spectra of nonconjugated 525 nm QDs can be presented as a superposition of PL bands related to exciton emission in CdSe cores (2.36 eV) and to hot electron‐hole emission via interface states (2.04, 2.20, 2.71 and 3.06 eV) localized at the CdSe/ZnS or ZnS/polymer interfaces. It is revealed that PL spectra of bioconjugated 525 nm QDs have changed dramatically with essential decreasing the hot electron‐hole recombination flow via interface states. This effect is explained on the base of the model deals with re‐charging QD interface states at the bioconjugation to OC125 antibodies. Raman scattering spectra of bioconjugated QDs can be presented as a superposition of Raman lines related to the silicon substrate. Raman lines deal with the vibration of COH, CH and OH groups of PEG polymer, which covered QDs, were detected additionally in nonconjugated QDs. It is revealed that the QD bioconjugation to OC 125 antibodies is accompanied by the changes in the intensity of all types of Raman lines. The explanation of details of bioconjugation effects has been proposed and discussed (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of growth temperature and spraying rate on the properties of ZnO:In films
Authors: Vent Merike , Kärber Erki , Unt Tarmo , Mere Arvo , Krunks Malle 
Published: May 2012

AbstractZnO:In thin films were deposited by chemical spray pyrolysis from zinc acetate solutions containing 3 at.% of InCl3. The films were grown in the temperature region of 400‐500 °C using solution spraying rates 0.6‐7.1 ml/min. ZnO:In films were characterized by XRD, Hall and van der Pauw methods. The dependence of the film resistivity vs growth temperature is parabolic. ZnO:In films with resistivity minimum of 3x10‐3 Ωcm can be deposited at 450 °C. The solution spraying rate has strong effect on the film resistivity, deposition rates below 3 ml/min result in high resistivities (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Band alignment at sputtered ZnSx O1–x/Cu(In,Ga)(Se,S)2 heterojunctions
Authors: Kieven D. , Grimm A. , Lauermann I. , Lux‐Steiner M. Ch. , Palm J. , Niesen T. , Klenk R. 
Published: May 2012

AbstractValence band offsets ΔEVBM at ZnSx O1–x/Cu(In,Ga)(Se,S)2 (CIGSSe) heterojunctions have been studied by photoemission spectroscopy (XPS, UPS) as a function of composition x in sputtered ZnSx O1–x films. In the composition range from ZnO to ZnS we found ΔEVBM between –(2.1 ± 0.3) eV and –(0.8 ± 0.4) eV, respectively. Considering the optical band gaps, the conduction band offsets ΔECBM range from –(0.1 ± 0.3) eV to +(1.4 ± 0.4) eV. These results suggest that sputtered ZnSx O1–x is suitable as substitution for the CdS buffer and ZnO window layers in standard chalcopyrite‐based solar cells. Current–voltage characteristics of the solar cells have been investigated as a function of the composition x. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A geometrical view of the shallow‐atmosphere approximation, with application to the semi‐Lagrangian departure point calculation
Authors: Thuburn J. , White A. A. 
Published: May 2012

AbstractThe widely used shallow‐atmosphere approximation is a geometrical approximation in which the metric departs from the usual Euclidean metric. This leads to a number of important consequences: shallow‐atmosphere space is intrinsically curved (i.e. non‐Euclidean), geodesics are not unique, the status of the centre of the Earth is uncertain, and position vectors are not well‐defined. Vector semi‐Lagrangian numerical models that use the shallow‐atmosphere approximation must allow explicitly for the non‐Euclidean geometry. During early testing of a new semi‐implicit, semi‐Lagrangian dynamical core, a semi‐implicit (Crank–Nicolson) discretization of the vector departure point equation was found to lead to an instability in deep‐atmosphere (i.e. Euclidean) geometry, but not in shallow‐atmosphere geometry. The instability can be avoided by an alternative treatment in which the departure point equation is projected onto its horizontal and vertical components before discretization. Interestingly, this stable treatment of the deep‐atmosphere case makes use of much of the mathematical machinery of the shallow‐atmosphere departure point calculation. Copyright © 2012 Royal Meteorological Society and British Crown Copyright, the Met Office
Benzothiadiazoles as DNA intercalators: Docking and simulation
Authors: Netz Paulo Augusto 
Published: May 2012

AbstractSome organic dyes, derivatives of the 4‐(arylethynyl)‐7‐(4‐methoxyphenyl)‐2,1,3‐benzothiadiazoles (BTDs) bind strongly to double stranded DNA, exhibiting a strong increase in the fluorescence intensity. Due to this property, they were proposed as very sensitive probes for DNA detection and quantification. The details of the interaction mechanism, however, are unknown. In this work, we use docking and molecular dynamics simulations to study the interactions of these BTDs with DNA. We used a docking protocol where the receptor is a modified canonical oligonucleotide, with a gap, to sample intercalation and minor groove binding modes. Starting from several independent but energetically favorable docking poses, molecular dynamics simulations were carried out, investigating the ligand‐DNA interactions and the time evolution of the DNA structure. We observed, in agreement with experimental results, that the presence of the ethynyl spacer in the ligand stabilizes the intercalation binding mode, yielding strong interactions with DNA and large residence times. © 2012 Wiley Periodicals, Inc.
The impacts of performance relative to analyst forecasts and analyst coverage on firm R&D intensity
Authors: Gentry Richard J , Shen Wei 
Published: May 2012

AbstractTaking an agency theory perspective of managers as risk averse and self‐interest seeking and focusing on externally generated analyst forecasts as the performance target, we propose that managers tend to cut R&D expenses when they are under pressure to meet analyst forecasts, especially when they face an increase in employment risk after missing the forecasts. We further argue that analyst coverage can serve as an external monitoring mechanism to help contain this agency problem. We test these arguments with data from a sample of U.S. manufacturing firms during the period of 1979 to 2005. Copyright © 2012 John Wiley & Sons, Ltd.
Numerical Prediction of Iron Flow and Bottom Erosion in the Blast Furnace Hearth
Authors: Shao Lei , Saxén Henrik 
Published: May 2012

AbstractThe blast furnace (BF) campaign life, which is limited by the hearth erosion, will be decisive for the process to maintain its dominance in ore‐based iron production, so timely prediction of the hearth erosion and proper measures to protect the hearth are important issues. The erosion at the hearth bottom has not received much attention, even though the region is believed to be the most vulnerable part of the hearth. A computational fluid dynamic (CFD) model has been developed to deepen the understanding of iron flow and refractory erosion at the bottom of the hearth. Key boundary and internal conditions, such as slag–iron interface and dead man state, are provided by a BF drainage model which reproduces the tapping process. Simulations with the CFD model illustrate how different factors affect the flow pattern, hearth erosion profile, and bottom breakage ratio. It is shown that the dead man state plays an important role for the flow behavior and erosion conditions in the hearth. The model is demonstrated to predict two erosion types that are commonly encountered in practice.
Gut stem cells in tissue renewal and disease: methods, markers, and myths
Authors: Rizk Pamela , Barker Nick 
Published: May 2012

AbstractHomeostasis in adult tissue is maintained by the activity of a minor population of long‐lived resident stem cells. These adult stem cells are defined by two essential attributes, self‐renewal and multipotency, and their physiological activity is regulated by a specialized microenvironment, the stem cell niche. These adult stem cells are generally considered to divide infrequently, and cell expansion is mainly achieved through the rapid proliferation of transit amplifying progenitors before they undergo terminal differentiation. Organs that operate in abrasive environments, such as the mucosa of the skin, intestine, and stomach, display a higher tissue turnover rate, which consequently places them at higher risk of developing cancer. Indeed, colorectal cancer (CRC) is one of the most frequent cancers worldwide, with over a million new cases every year. Our understanding of stem cell function in tissue homeostasis and their potential role in cancer development has been greatly hampered by the lack of reliable specific biomarkers, but recent discoveries of membrane bound biomarkers promise great progress in the field. Here we review the current advances toward identifying the stem cells of the gastrointestinal tract and in understanding their microenvironmental regulation, and also discuss their implications for human cancer. WIREs Syst Biol Med 2012. doi: 10.1002/wsbm.1176This article is categorized under:

Developmental Biology > Developmental Processes in Health and Disease
Developmental Biology > Stem Cell Biology and Regeneration
The Effects of Childhood SNAP Use and Neighborhood Conditions on Adult Body Mass Index
Authors: Vartanian Thomas P. , Houser Linda 
Published: May 2012

Abstract
The disproportionate number of individuals who are obese or overweight in the low-income U.S. population has raised interest in the influence of neighborhood conditions and public assistance programs on weight and health. Generally, neighborhood effects and program participation effects have been explored in separate studies. We unite these two areas of inquiry, using the 1968–2005 Panel Study of Income Dynamics (PSID) to examine the long-term effects of childhood Supplemental Nutrition Assistance Program (SNAP) participation, neighborhood conditions, and the interaction of these two, on adult body mass index (BMI). Using sibling fixed-effects models to account for selection bias, we find that relative to children in other low-income families, children in SNAP-recipient households have higher average adult BMI values. However, the effects of childhood SNAP usage are sensitive to both residential neighborhood and age at receipt. For those growing up in advantaged neighborhoods, projected adult BMI is higher for children in SNAP-recipient households than for children in low-income, nonrecipient households. In contrast, for those growing up in less-advantaged areas, adult BMI differences between children in SNAP-recipient and those in low-income, nonrecipient households are small. SNAP usage during preschool years (0 to 4) has no impact on adult BMI scores. However, at later childhood ages, the time elapsed receiving SNAP income increases adult BMI values relative to a condition of low-income nonreceipt.
Relationship of roll and pitch oscillations in a fin flapping at transitional to high Reynolds numbers
Authors: Bandyopadhyay Promode R. , Beal David N. , Hrubes J. Dana , Mangalam Arun 
Published: May 2012

AbstractHydrodynamic effects of the relationship between the roll and pitch oscillations in low-aspect-ratio fins, with a laminar section and a rounded leading edge, flapping at transitional to moderately high Reynolds numbers, are considered. The fin is hinged at one end and its roll amplitude is large. Also examined is how this relationship is affected by spanwise twist, which alters the pitch oscillation amplitude and its phase relative to the roll motion. Force, efficiency and surface hot-film-anemometry measurements, and flow visualization are carried out in a tow tank. A fin of an abstracted penguin-wing planform and a NACA 0012 cross-section is used, and the chord Reynolds number varies from 3558 to 150 000 based on total speed. The fin is forced near the natural shedding frequency. Strouhal number and pitch amplitude are directly related when thrust is produced, and efficiency is maximized in narrow combinations of Strouhal number and pitch amplitude when oscillation of the leading-edge stagnation point is minimal. Twist makes the angle of attack uniform along the span and enhances thrust by up to 24 %, while maintaining high efficiency. Only 5 % of the power required to roll is spent to pitch, and yet roll and pitch are directly related. During hovering, dye visualization shows that a diffused leading-edge vortex is produced in rigid fins, which enlarges along the span; however, twist makes the vortex more uniform and the fin in turn requires less power to roll. Low-order phase maps of the measurements of force oscillation versus its derivative are modelled as due to van der Pol oscillators; the higher-order maps show trends in the sub-regimes of the transitional Reynolds number. Fin oscillation imparts a chordwise fluid motion, yielding a Stokes wave in the near-wall vorticity layer. When the roll and pitch oscillations are directly related, the wave is optimized: causing vorticity lift-up as the fin is decelerated at the roll extremity; the potential energy at the stagnation point is converted into kinetic energy; a vortex is produced as the lifted vorticity is wrapped around the leading edge; and free-stream reattachment keeps the vortex trapped. When the twist oscillation is phased along the span, this vortex becomes self-preserving at all amplitudes of twist, indicating the most stable (low-bandwidth) tuned nature.
Protein v. carbohydrate intake differentially affects liking- and wanting-related brain signalling
Authors: Born Jurriaan M. , Martens Mieke J. I. , Lemmens Sofie G. T. , Goebel Rainer , Westerterp-Plantenga Margriet S. 
Published: May 2012

Extreme macronutrient intakes possibly lead to different brain signalling. The aim of the present study was to determine the effects of ingesting high-protein v. high-carbohydrate food on liking and wanting task-related brain signalling (TRS) and subsequent macronutrient intake. A total of thirty female subjects (21·6 (sd 2·2) years, BMI 25·0 (sd 3·7) kg/m2) completed four functional MRI scans: two fasted and two satiated on two different days. During the scans, subjects rated all food items for liking and wanting, thereby choosing the subsequent meal. The results show that high-protein (PROT) v. high-carbohydrate (CARB) conditions were generated using protein or carbohydrate drinks at the first meal. Energy intake and hunger were recorded. PROT (protein: 53·7 (sd 2·1) percentage of energy (En%); carbohydrate: 6·4 (sd 1·3) En%) and CARB conditions (protein: 11·8 (sd 0·6) En%; carbohydrate: 70·0 (sd 2·4) En%) were achieved during the first meal, while the second meals were not different between the conditions. Hunger, energy intake, and behavioural liking and wanting ratings were decreased after the first meal (P< 0·001). Comparing the first with the second meal, the macronutrient content changed: carbohydrate − 26·9 En% in the CARB condition, protein − 37·8 En% in the PROT condition. After the first meal in the CARB condition, wanting TRS was increased in the hypothalamus. After the first meal in the PROT condition, liking TRS was decreased in the putamen (P< 0·05). The change in energy intake from the first to the second meal was inversely related to the change in liking TRS in the striatum and hypothalamus in the CARB condition and positively related in the PROT condition (P< 0·05). In conclusion, wanting and liking TRS were affected differentially with a change in carbohydrate or protein intake, underscoring subsequent energy intake and shift in macronutrient composition.
HEALTH INEQUALITIES AMONG URBAN CHILDREN IN INDIA: A COMPARATIVE ASSESSMENT OF EMPOWERED ACTION GROUP (EAG) AND SOUTH INDIAN STATES
Authors: AROKIASAMY P. , JAIN KSHIPRA , GOLI SRINIVAS , PRADHAN JALANDHAR 
Published: May 2012

SummaryAs India rapidly urbanizes, within urban areas socioeconomic disparities are rising and health inequality among urban children is an emerging challenge. This paper assesses the relative contribution of socioeconomic factors to child health inequalities between the less developed Empowered Action Group (EAG) states and more developed South Indian states in urban India using data from the 2005–06 National Family Health Survey. Focusing on urban health from varying regional and developmental contexts, socioeconomic inequalities in child health are examined first using Concentration Indices (CIs) and then the contributions of socioeconomic factors to the CIs of health variables are derived. The results reveal, in order of importance, pronounced contributions of household economic status, parent's illiteracy and caste to urban child health inequalities in the South Indian states. In contrast, parent's illiteracy, poor economic status, being Muslim and child birth order 3 or more are major contributors to health inequalities among urban children in the EAG states. The results suggest the need to adopt different health policy interventions in accordance with the pattern of varying contributions of socioeconomic factors to child health inequalities between the more developed South Indian states and less developed EAG states.
Laryngeal paraganglioma in an irradiated neck
Authors: Pham T A , De Freitas R , Young G , Safdar A 
Published: May 2012

AbstractObjective:We present the first reported case of a paraganglioma of the larynx occurring concurrently with squamous cell carcinoma in an irradiated neck.Method:We present a case report and a literature review of paraganglioma of the larynx.Case report:A 78-year-old woman was found to have a mass on the laryngeal surface of the epiglottis and non-functioning larynx, four months after radical radiotherapy for biopsy-proven squamous cell carcinoma. Repeated positron emission tomography computed tomography was highly suggestive of residual malignancy. Given these findings, and the fact that the patient was aspirating, she was treated with total laryngectomy, and was found to have a paraganglioma of the larynx.Conclusion:This is the first report of such a case. Its importance is three-fold in that it demonstrates: the coexistence of paraganglioma and squamous cell carcinoma; the difficulties that can be encountered in the diagnosis; and the use of radiotherapy in the treatment of paraganglioma.
Chronic non-granulomatous supraglottitis: a rare and difficult disease
Authors: Ledgerwood L G , Belafsky P C 
Published: May 2012

AbstractObjectives:To examine chronic non-granulomatous supraglottitis, a rare disorder of uncertain aetiology with few reported cases in the literature.Case reports:We describe two cases of chronic non-granulomatous supraglottitis that led to persistent respiratory compromise. Patients underwent extensive investigation that failed to reveal a definitive diagnosis.Conclusion:In patients suffering from chronic inflammation of the supraglottic larynx without evidence of infection, neoplasm or granulomatous disease, many disorders must be ruled out in order to diagnose chronic non-granulomatous supraglottitis, which is a diagnosis of exclusion. We review the literature on this rare entity, discuss current management strategies, and suggest an algorithm for diagnostic investigation.