bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of young age on outcomes in head and neck cancer
Authors: Lassig Amy Anne D. , Lindgren Bruce R. , Fernandes Patricia , Cooper Sarah , Ardeshipour Farhad , Schotzko Chelsea , Yueh Bevan 
Published: May 2013

Objectives/HypothesisMany head and neck surgeons believe that young patients with head and neck cancer (HNCA) have poorer outcomes than older patients, whereas the evidence in the literature is mixed. We sought to review our HNCA population to evaluate for survival differences between young and older patients.Study DesignMatched pair retrospective cohort study.MethodsA matched pair retrospective cohort study was completed of mucosal HNCA patients at our academic center (2003–2008). Patients aged 45 or less when diagnosed were identified as cases and matched one‐to‐one to controls by site of tumor, stage of disease, and gender. Risk factors, disease and treatment variables, and survival outcomes were compared between groups. In addition, a subset survival analysis was completed with oropharyngeal cancer patients and nonoropharyngeal cancer patients.ResultsThere were 87 cases matched to 87 controls. Despite no difference in T and N stage between groups, cases more frequently underwent neck dissection. On Kaplan‐Meier and multivariate analysis, overall survival was marginally better for all young patients, whereas disease‐free survival was significantly better. Within the subgroup analysis, the statistically significant disease‐free survival advantage was lost for young patients with oropharyngeal cancer but maintained for all other sites.ConclusionsIn this cohort, young HNCA patients had mildly improved overall survival but statistically greater disease‐free survival. There was no statistically significant survival difference between young and older patients with oropharyngeal cancer, potentially secondary to a human papillomavirus effect.Level of Evidence2b. Laryngoscope, 123:1896–1902, 2013
CO2‐Responsive Polymers
Authors: Lin Shaojian , Theato Patrick 
Published: May 2013

AbstractThis Review focuses on the recent progress in the area of CO2‐responsive polymers and provides detailed descriptions of these existing examples. CO2‐responsive polymers can be categorized into three types based on their CO2‐responsive groups: amidine, amine, and carboxyl groups. Compared with traditional temperature, pH, or light stimuli‐responsive polymers, CO2‐responsive polymers provide the advantage to use CO2 as a “green” trigger as well as to capture CO2 directly from air. In addition, the current challenges of CO2‐responsive polymers are discussed and the different solution methods are compared. Noteworthy, CO2‐responsive polymers are considered to have a prosperous future in various scientific areas.magnified image
Synthesis of π‐Conjugated Polymer Consisting of Pyrrole and Fluorene Units by Ru‐Catalyzed Site‐Selective Direct Arylation Polycondensation
Authors: Lu Wei , Kuwabara Junpei , Kanbara Takaki 
Published: May 2013

AbstractPolycondensation of 1‐(2‐pyrimidinyl)pyrrole with 2,7‐dibromo‐9,9‐dioctylfluorene via Ru‐catalyzed direct arylation gives the corresponding conjugated polymer with a molecular weight of 19 800 in 86% yield. The introduction of directing group, 2‐pyrimidinyl substituent, into the pyrrole monomer induces ortho‐metalation and provides the site‐selective direct arylation polycondensation at the α‐position of pyrrole unit without the protection of β‐position. The removal of 2‐pyrimidinyl substituent on the pyrrole unit proceeds efficiently and results in the enhancement of coplanarity along the main chain of the polymer.
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Polymer Solar Cells: An Overview
Authors: Singh Ram Prakash , Kushwaha Omkar Singh 
Published: May 2013

SummaryPolymer Solar cells being flexible, light weight, inexpensive, colorful and large area devices, portend potential for large scale grid power generation. The first major breakthrough in organic solar cell performance came in 1986 when Tang discovered that much higher efficiencies about 1% can be attained when electron donor (D) and electron acceptor (A) are brought together in one cell. With the discovery of photo induced electron transfer from a conjugated polymer to fullerene molecules in 1992, the bulk heterojunction (BHJ) polymer solar cell has become the most successful device structure developed in the field till date. Poly(3‐hexyl thiophene) (P3HT) has been the subject of intensive investigations upto 2008 yielding power conversion efficiencies (PCEs) around 5‐6%. OPV technology has grown during the past decade with cell efficiencies quadrupling. As alternative route of higher performance, two or more single cells can be combined in tandem structure. The most efficient tandem organic solar cell reported by Yang Yang's group has 8.62% power conversion efficiency (PCE) which has been further improved with an NREL – certified PCE of 10.6%. An overview of the above will be presented in this paper.
Silica based aerogel‐like materials obtained by quick microwave drying
Authors: Durães L. , Matias T. , Patrício R. , Portugal A. 
Published: May 2013

AbstractAerogel‐like silica based materials were obtained by microwave drying of the gels synthesized with methyltrimethoxysilane (MTMS) precursor. The microwave drying is an alternative ambient pressure drying technique for these nanostructured materials that allows a fast fine drying stage and avoids the high temperature cycles of conventional evaporative drying. The gels were synthesized by a two‐step acid‐base catalyzed sol‐gel process following the procedures described in an earlier work. After 2 days of aging, they were placed in an oven at 60°C, during one day, and then washed with distilled water at 40°C. Finally, the gels were dried in a microwave oven, at 450 W, in three cycles of two minutes each with two minutes of interval. During drying, a reduction of the gel volume was observed, but the major part of this volume was recovered by spring‐back effect in 2 days, giving aerogel‐like materials with a density in the interval 60–80 kg/m3. The final materials are monolithic, flexible and have a thermal conductivity of ˜0.04 W/(m K), which make them suitable for insulation applications. Additionally, they exhibit high hydrophobicity (contact angle ˜150°) and surface area (414 m2/g), what can be beneficial for adsorption of some organic pollutants.
The effect of Bi addition on the microstructure and tensile properties of cast Al‐15%Mg2Si composite
Authors: Akrami A. , Emamy M. , Mousavian H. 
Published: May 2013

AbstractIn the current research, the influence of different concentrations of Bi (0.01–0.3 wt.%) on the microstructure and tensile properties of Al‐15 wt.% Mg2Si in‐situ metal matrix composite (MMC) has been investigated. It was found that 0.03 wt.% Bi changes the primary Mg2Si shape from large to irregular or dendritic to polyhedral shape. The average particle size of Mg2Si also decreases from 65 μm to 20 μm by adding 0.03% Bi. Microstructural observations by scanning electron microscope (SEM) also depicted that the morphology of the eutectic Mg2Si phase alters from flake‐like to fine fiber or dot like. Further investigations on tensile testing revealed that the optimum amount of Bi level is 0.03% for improving both ultimate tensile test (UTS) and elongation values.
Parametric analysis of constant‐moment zone length in four point bending of reinforced concrete beams
Authors: Galić M. , Marović P. , Harapin A. 
Published: May 2013

AbstractThis paper describes performed numerical parametric analyses of constant‐moment zone length in four point bending of reinforced concrete structures by a developed three‐dimensional numerical material model for analyzing reinforced concrete structures. The model is defined by elementary material parameters which can be obtained by a standard uniaxial test so that the very complex behaviour of reinforced concrete structures can be described simply and effectively but with a sufficiently accurate model. The aim is to reproduce and to compare obtained results with numerical two‐dimensional model by Fantilli et al. and experimental results by Weiss et al. where a constant‐moment zone length is investigated to determine whether the flexural response of reinforced concrete beams is size (length) dependent. Parametric analyses will be performed on normal‐strength concrete (NSC) and high‐strength concrete (HSC) beams with four different constant‐moment zone lengths and two different reinforcement ratios. As the developed model enables a very detailed and precise analysis of reinforced concrete structures until crushing with a high accuracy, we hope to confirm Fantilli et al. results what could lead to the improvement of Eurocode 2 where the size effect on the structural response of compressed concrete is not taken into account.
Simulation of pulse laser welding of a thin metal and comparison with other heat sources
Authors: Arai T. 
Published: May 2013

AbstractLaser welding by a pulse beam became recently more common than the welding by continuous wave in the case of performed precise and accurate welding of sheet metal. However, the exact theoretical analysis of laser welding by a pulse beam was not conducted. In most of the cases, only the processing results of pulse welding were shown. In laser welding, the internal welding conditions during the processing cannot be observed from the outside. To show more concrete insights of the processing, simulation is one of the effective methods for that purpose. Furthermore, phenomenons which occur insight the material due to one pulse are not understood well. At the present, laser pulse beam processing comes to be required for an exact welding. Thus, the elucidation of the phenomenons helps to understand pulsed welding and will result in a decrease of the sheet metal deformation. This paper describes the processing of pulsed welding by theoretical analysis and simulation. Furthermore, the deformation of the sheet metal which results from the pulsed welding was considered. The welding characteristics were compared in detail using the different continuous wave heat source of circular laser. As a result, it could be shown that in the case of pulse beam welding the heat influence was 70% or less and due to deformations it became 1/10 or less compared to with continuous wave welding.
Heat transfer and stress concentrations in a two‐phase polycrystalline composite structure. Part I: Theoretical modelling of heat transfer
Authors: Sadowski T. , Golewski P. 
Published: May 2013

AbstractThe aim of the paper is a numerical analysis of heat transfer in polycrystalline composites, containing metallic or elastic interfaces, i. e. metal‐ceramic composites (MCCs) or ceramic matrix composites (CMCs). An example of MCCs is a two‐phase material composed of brittle grains WC joined by the plastic binder Co. The work focuses also on the description of the heat concentrations in composites due to temperature changes, taking into account the real material internal structure, which includes grain shapes and interfaces. Under thermal loading the heat transfer in MMCs is mainly through metallic interfaces, where the heat flux concentrations occur due to different thermal properties of both phases. They can cause also stress concentrations and act as sources of damage initiators at the binder/carbide grains interfaces. The different contents of the interphase between elastic grains were taken into account in the analysis, starting from the interfaces of the small thickness: 2–4 μm and volume content approximately 10% (e. g. Co), to the higher values up to 30%. The major conclusion is the following: the volume content of the metallic phase (Co binder) and its architecture (spatial distribution) inside the material strongly influences the heat transfer through the composites.
Temperature‐induced changes of magnetic resonance relaxation times in the human brain: A postmortem study
Authors: Birkl Christoph , Langkammer Christian , Haybaeck Johannes , Ernst Christina , Stollberger Rudolf , Fazekas Franz , Ropele Stefan 
Published: May 2013

PurposeMagnetic resonance relaxation times of most tissues are expected to depend on temperature, which can impact findings in postmortem magnetic resonance imaging or when using magnetic resonance imaging for relaxation‐based thermometry. The purpose of this study was to investigate the exact temperature dependency of the relaxation times T1, T2, T2*, and the magnetization transfer ratio in different structures of the human brain.MethodsTo prevent fixation and autolysis effects, this study was performed with fresh postmortem brain tissues. Following autopsy, coronal brain slices from five deceased subjects were subjected to relaxometry at 3T in a temperature range between 4°C and 37°C. Heating of the tissue was achieved by flushing the vacuum packed brain slices with water at a predefined temperature.ResultsT1 showed a linear dependency on temperature with the highest temperature coefficient in the cortex (17.4 ms/°C) and the lowest in the white matter (3.4 ms/°C). T2 did not depend on temperature. T2* and magnetization transfer ratio scaled with temperature only in deep gray matter.ConclusionThe temperature coefficient for T1 is higher than expected from previous reports and varies across brain structures. The coefficients obtained in this study can serve as reference for thermometry or for correcting quantitative postmortem magnetic resonance imaging. Magn Reson Med 71:1575–1580, 2014. © 2013 Wiley Periodicals, Inc.
Longitudinal features of stir bright signal in FSHD1
Authors: Friedman Seth D. , Poliachik Sandra L. , Otto Randolph K. , Carter Gregory T. , Budech Christopher B. , Bird Thomas D. , Miller Daniel G. , Shaw Dennis W.W. 
Published: May 2013

ABSTRACTIntroduction: Magnetic resonance imaging of muscle shows short tau‐inversion recovery (STIR) brightness in autosomal dominant facioscapulohumeral muscular dystrophy (FSHD1) suggestive of active inflammation/injury. We measured the longitudinal stability/progression of this potential disease biomarker. Methods: Nine subjects underwent calf MRI imaging over 2 years. Two radiologists evaluated qualitative muscle changes. Results: In 3/9 subjects, calf muscles demonstrated moderate/severe STIR hyperintensity at Time 1 that had progressed to fatty replacement 2 years later (Time 2). In the remaining subjects, moderate/severe muscle STIR abnormalities, when present, were consistent between exams. Mild STIR+ elevations had roughly similar patterns between exams. Conclusions: Moderate/severe STIR hyperintensities often foreshadow fatty replacement over a 2‐year interval. Whether longer time courses are required to observe muscle degeneration and fatty replacement in some subjects remains to be explored. Muscle Nerve 49: 257–260, 2014
Influence of multiple stimuli on the lower critical solution temperature of new cationic poly(N‐acryloyl‐N′‐ethylpiperazine‐co‐N‐isopropylacrylamide) solutions
Authors: Deen G. Roshan , Zhen Quah Li , Hao Mah Chin , Jun Loh Xian 
Published: May 2013

ABSTRACTNew multi‐stimuli responsive cationic copolymers based on N‐acryloyl‐N′‐ethyl piperazine (AcrNEP) and N‐isopropylacrylamide (NIPAM) were prepared by thermal free‐radical solution polymerization in dioxane at 75 °C. The chemical composition of the copolymers was determined by 1H NMR spectroscopy and was found that the copolymers were slightly rich in NIPAM content than that of AcrNEP. The reactivity of the two monomers for the copolymerization reaction was evaluated by the extended Kelen‐Tüdös method. The distribution of monomer sequence in the copolymer chain was estimated using the terminal copolymerization model. The maximum tendency to alternation (∼ 70%) was at 60 mol % of AcrNEP in the monomer feed. The copolymers were readily soluble in water at room temperature at all compositions and exhibited well‐defined lower critical solution temperature (LCST) phenomenon. The influence of various stimuli such as pH, temperature, simple inorganic salts, and surfactants on the LCST of the copolymers was studied in detail. Simple inorganic salts such as sodium chloride, sodium bromide, and sodium sulfate showed a salting‐out effect while sodium iodide showed a salting‐in effect. The salting‐out coefficient of the salts were calculated using the Sestchenow method, and the salting trend followed the order SO42− > Cl− > Br− > I−. The divalent salt was more effective in lowering the LCST than the monovalent salts. The cationic surfactant hexadecyl trimethylammonium bromide at concentrations above the critical micelle concentration caused a gradual increase in the LCST of the copolymer solutions. The intrinsic viscosity and light scattering behavior of the copolymers in water and in sodium chloride solutions were studied in detail. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1175–1183
What Functional Aspects Explain Patients' Impression of Change after Rehabilitation for Long‐lasting Low Back Pain?
Authors: Anderson Bodil , Lygren Hildegunn , Magnussen Liv Heide , Eide Geir Egil , Strand Liv Inger 
Published: May 2013

AbstractBackgroundPhysical tests and self‐report measures are being used to measure physical functioning. The latter tends to be preferred in intervention studies.PurposeTo examine whether the patients' global impression of change (PGIC) after rehabilitation was explained by change in pain, daily functioning, fear‐avoidance of activities and various physical aspects, expecting contribution primarily by the self‐reported measures.MethodsA test‐retest design, within a prospective cohort study of patients with long‐lasting low back pain. 96 patients were consecutively recruited from an outpatient spine clinic, assessed by three self‐report questionnaires and seven physical tests at inclusion and after 3.5 weeks of multidisciplinary treatment. With PGIC as the dependent variable, linear regression analyses of all variables were performed. The study was approved by the Regional Committee for Medical Research Ethics and the National Data Inspectorate of Norway.ResultsIn unadjusted analysis, change in pain, daily functioning and change in six physical tests contributed to the explained variance (R2: 6–24%). In the adjusted analysis, only pain and back endurance strength contributed (adjusted R2: 48%). In the final backward stepwise blockwise analyses, daily functioning and spinal mobility were also found to contribute to the explained variance (R2: 48%). The time span of 3.5 weeks of training is too short to give a lasting effect, but the contribution to explained variance of PGIC of self‐report measures and physical tests were the focus of this study, not the effect of training.ConclusionMost measures demonstrated change that was of significance to the patients after rehabilitation. Change in spinal mobility and back strength assessed by physical tests contributed to explain the patients' impression of change after controlling for change in pain and daily life functioning and may seem important to assess in addition to the self‐report measures in intervention studies. Copyright © 2013 John Wiley & Sons, Ltd.
Spin relaxation length in quantum dot spin LEDs
Authors: Höpfner Henning , Fritsche Carola , Ludwig Arne , Ludwig Astrid , Stromberg Frank , Wende Heiko , Keune Werner , Reuter Dirk , Wieck Andreas D. , Gerhardt Nils C. , Hofmann Martin R. 
Published: May 2013

AbstractWe analyse the spin relaxation length during vertical electron transport in spin light‐emitting diode devices at room temperature. We obtain a spin relaxation length of 27 nm in remanence. When a magnetic field is applied, spin relaxation is significantly reduced during transport to the active region of the device. This results in a nearly doubled spin relaxation length at 2T magnetic field strength.
An enhanced technique for automated determination of 15N signatures of N2, (N2+N2O) and N2O in gas samples
Authors: Lewicka‐Szczebak Dominika , Well Reinhard , Giesemann Anette , Rohe Lena , Wolf Ulrike 
Published: May 2013

RATIONALEAn enhanced analytical approach for analyzing gaseous products from 15N‐enriched pools has been developed. This technique can be used to quantify nitrous oxide (N2O) and dinitrogen (N2) fluxes from denitrification. It can also help in distinguishing different N2‐ and N2O‐forming processes, such as denitrification, nitrification, anaerobic ammonium oxidation or co‐denitrification.METHODSThe measurement instrumentation was based on a commercially available automatic preparation system allowing collection and separation of gaseous samples. The sample transfer paths, valves, liquid nitrogen traps, gas chromatography column and open split of the original system were modified. A reduction oven (Cu) was added in order to eliminate oxygen and measure N2O‐N as N2. Gases leaving the separation system entered an isotope ratio mass spectrometer where masses 28N2, 29N2 and 30N2 were measured.RESULTSThe enhanced technique enabled rapid simultaneous measurement of stable isotope ratios 29N2/28N2 and 30N2/28N2 originating from dinitrogen alone (N2) and from the sum of the denitrification products (N2+N2O) as well as the determination of 15N enrichment in N2O. The 15N fraction in the N pool undergoing N2 and N2O production (15XN) and the contribution of N2 and N2O originating from this pool (d) were determined with satisfactory accuracy of better than 3.3% and 2.9%, respectively.CONCLUSIONSThe precision and accuracy of this method were comparable with or better than previously reported for similar measurements. The proposed method allows for the analysis of all quantities within one run, thus reducing the measurement and sample preparation time as well as increasing the reliability of the results. Copyright © 2013 John Wiley & Sons, Ltd.
Predicting dependences using domain‐based coupling
Authors: Aryani Amir , Perin Fabrizio , Lungu Mircea , Mahmood Abdun Naser , Nierstrasz Oscar 
Published: May 2013

SUMMARYSoftware dependences play a vital role in programme comprehension, change impact analysis and other software maintenance activities. Traditionally, these activities are supported by source code analysis; however, the source code is sometimes inaccessible or difficult to analyse, as in hybrid systems composed of source code in multiple languages using various paradigms (e.g. object‐oriented programming and relational databases). Moreover, not all stakeholders have adequate knowledge to perform such analyses. For example, non‐technical domain experts and consultants raise most maintenance requests; however, they cannot predict the cost and impact of the requested changes without the support of the developers. We propose a novel approach to predicting software dependences by exploiting the coupling present in domain‐level information. Our approach is independent of the software implementation; hence, it can be used to approximate architectural dependences without access to the source code or the database. As such, it can be applied to hybrid systems with heterogeneous source code or legacy systems with missing source code. In addition, this approach is based solely on information visible and understandable to domain users; therefore, it can be efficiently used by domain experts without the support of software developers. We evaluate our approach with a case study on a large‐scale enterprise system, in which we demonstrate how up to 65% of the source code dependences and 77% of the database dependences are predicted solely based on domain information. Copyright © 2013 John Wiley & Sons, Ltd.