bluuebunny/crossref_metadata_2025 huggingface dataset:
Rigid Polyimide Networks End‐Linked with Tri‐ and Tetra‐armed Crosslinkers
Authors: Yoshihara Naoki , Hosono Nobuhiko , Ohshima Ryota , Totani Kenro , Watanabe Toshiyuki
Published: April 2014

Rigid polymer networks with aromatic polyimide (PI) backbones end‐linked with symmetric crosslinkers are designed. 1,3,5‐Tris(4‐aminophenyl)benzene (TAPB) and tetra(4‐aminophenyl)methane (TAPM) are used as the crosslinkers. Whereas TAPB has three reactive amines at planar threefold symmetric (C3) positions, TAPM has four amines at tetragonal (S4) positions. Poly(amide acid) (PAA) precursors are end‐linked with TAPB or TAPM to make PAA networks. The crosslinking reaction efficiencies and mechanical properties of the PAA gels are investigated by the sol fraction method and compressive stress–strain tests, respectively. The PAA gels are successively transformed to PI gels through chemical imidization treatments. From the swelling behavior, it is found that the PI gels have high void contents up to 70%.

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A Meyers type regularity result for approximations of second order elliptic operators by P1 finite elements
Authors: Badr Nadine , Russ Emmanuel
Published: April 2014

We prove a Meyers type regularity estimate for approximate solutions of second order elliptic equations obtained by P1 finite elements. The proofs rely on interpolation results for Sobolev spaces on graphs. Estimates for second order elliptic operators on rather general graphs are also obtained.
Generalized Hardy, Copson, Leindler and Bennett inequalities on time scales
Authors: Saker S. H. , O'Regan D. , Agarwal R.
Published: April 2014

In this paper, we prove some new dynamic inequalities on time scales using Hölder's inequality and Keller's chain rule on time scales. These inequalities, as special cases when the time scale and when , contain some generalizations of integral and discrete inequalities due to Hardy, Copson, Leindler and Bennett.
Interval vortex methods
Authors: Lin Qun , Ying Lung‐an
Published: April 2014

By means of the integral version of vortex equation, the technique of Green's function, and the vorticity‐to‐velocity map, a new kind of interval methods for solving the initial‐periodic boundary value problem of two‐dimensional incompressible Navier–Stokes equation is introduced, which consists of both an approximate scheme and a set of pointwise intervals covering the exact solution. The convergence theorem corresponding to the scheme is proved, and the order of error width for the two‐sided bounds is also considered. Finally, a simple numerical example illustrates our corroboration. © 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 1368–1396, 2014
Synthesis of a new rhodamine‐containing block copolymer for highly selective and sensitive detection of Cu2+ and CN− ions in aqueous media
Authors: Banerjee Rakesh , Pal Deep Sankar , Dhara Dibakar
Published: April 2014

Development of new chemosensors that are selective and sensitive to Cu2+ and CN− ions, especially in aqueous media, is of tremendous importance. We report the synthesis of a new block copolymer that is capable of highly selective and sensitive detection of Cu2+ and CN− ions in aqueous media. Poly(t‐butylacrylate)‐block‐poly(3‐bromopropylacrylate) was prepared using the reversible addition–fragmentation chain transfer polymerization technique. This block copolymer was reacted with 2,4‐dihydroxybenzaldehyde followed by reaction with rhodamine B hydrazide for successful incorporation of the desired rhodamine units into the block copolymer structure. Cu2+‐induced opening of the spirolactam ring of the rhodamine units resulted in rapid and easily noticeable colour change, thus enabling a highly selective detection of Cu2+ ions in aqueous media for concentrations as low as 2 µmol L−1. We further demonstrate that this Cu2+ bound polymer complex can further act as a selective and sensitive sensing platform for CN− in aqueous media with concentrations <1 µmol L−1 (0.06 ppm). Moreover, the polymer can also be used to remove Cu2+ from aqueous media. © 2014 Society of Chemical Industry
Inter‐hospital variation in the frequency of sinus surgery in children with cystic fibrosis
Authors: Virgin Frank W. , Huang Lin , Roberson David W. , Sawicki Gregory S.
Published: April 2014

Background

Chronic rhinosinusitis and nasal polyposis are common conditions in cystic fibrosis (CF). Approximately 2–3% of pediatric CF patients per year have sinus disease requiring surgery. The purpose of this study was to evaluate the variation of sinus surgery rates in pediatric CF patients across multiple US pediatric hospitals.

Methods

The Pediatric Health Information System (PHIS) compiles inpatient administrative data from 42 pediatric hospitals. We conducted a retrospective analysis of PHIS for the period January 1, 2008 to January 1, 2011 to evaluate frequency of sinus surgery at each hospital. We identified CF patients and sinus surgery during inpatient encounters using ICD‐9 codes. Demographic data and data for each hospital on hospital size, number of pediatric otolaryngologists, average FEV1, and percentage of patients meeting minimum care guidelines were collected. Twenty‐nine hospitals were included in analysis using mixed‐effects logistic regression models for occurrence of sinus surgery.

Results

We identified 5,194 CF patients, accounting for 18,788 unique encounters among 29 hospitals. 880 patients underwent 1,397 sinus operations. Total number of CF patients at each institution ranged from 39 to 364 and total number of sinus surgeries ranged from 4 to 205, over the 3‐year period. Variation in the rate of sinus surgery with hospital encounter was observed (1–24%). Hospital‐average lung function (P = 0.56), number of otolaryngologists (P = 0.65) were not found to be predictors of sinus surgery. The size of the CF center (P = 0.01), hospital size (P = 0.05), and age at admission (P ≤ 0.0001) were associated with an increased frequency of sinus surgery. However, with multivariable analysis, only size of the CF center and age of admission remained statistically significant predictors of surgery with admission.

Conclusions

There is large variation in the incidence of sinus surgery for CF in 29 of the largest freestanding pediatric hospitals. This study highlights remarkable variation in clinical practice and underscores the need for further research into the indications and benefits of sinus surgery in pediatric patients with CF. Pediatr Pulmonol. 2015; 50:231–235. © 2014 Wiley Periodicals, Inc.
A review and re‐interpretation of a group‐sequential approach to sample size re‐estimation in two‐stage trials
Authors: Bowden J. , Mander A.
Published: April 2014

In this paper, we review the adaptive design methodology of Li et al. (Biostatistics 3:277–287) for two‐stage trials with mid‐trial sample size adjustment. We argue that it is closer in principle to a group sequential design, in spite of its obvious adaptive element. Several extensions are proposed that aim to make it even more attractive and transparent alternative to a standard (fixed sample size) trial for funding bodies to consider. These enable a cap to be put on the maximum sample size and for the trial data to be analysed using standard methods at its conclusion. The regulatory view of trials incorporating unblinded sample size re‐estimation is also discussed. © 2014 The Authors. Pharmaceutical Statistics published by John Wiley & Sons, Ltd.
Importance of Reservoir Tributaries to Spawning of Migratory Fish in the Upper Paraná River
Authors: da Silva P. S. , Makrakis M. C. , Miranda L. E. , Makrakis S. , Assumpção L. , Paula S. , Dias J. H. P. , Marques H.
Published: April 2014

Regulation of rivers by dams transforms previously lotic reaches above the dam into lentic ones and limits or prevents longitudinal connectivity, which impairs access to suitable habitats for the reproduction of many migratory fish species. Frequently, unregulated tributaries can provide important habitat heterogeneity to a regulated river and may mitigate the influence of impoundments on the mainstem river. We evaluated the importance of tributaries to spawning of migratory fish species over three spawning seasons, by comparing several abiotic conditions and larval fish distributions in four rivers that are tributaries to an impounded reach of the Upper Paraná River, Brazil. Our study confirmed reproduction of at least 8 long‐distance migrators, likely nine, out of a total of 19 occurring in the Upper Paraná River. Total larval densities and percentage species composition differed among tributaries, but the differences were not consistent among spawning seasons and unexpectedly were not strongly related to annual differences in temperature and hydrology. We hypothesize that under present conditions, densities of larvae of migratory species may be better related to efficiency of fish passage facilities than to temperature and hydrology. Our study indicates that adult fish are finding suitable habitat for spawning in tributaries, fish eggs are developing into larvae, and larvae are finding suitable rearing space in lagoons adjacent to the tributaries. Our findings also suggest the need for establishment of protected areas in unregulated and lightly regulated tributaries to preserve essential spawning and nursery habitats. Copyright © 2014 John Wiley & Sons, Ltd.
Determination of Mg concentration and distribution in MgxZn1−xO films for photonic devices application
Authors: Ferlito E. P. , Ricciari R. , Padalino M. , Grasso S. , Battaglia A. , Sciuto M. , Mello D. , Tapfer L. , Gerardi C.
Published: April 2014

Among the transparent conductor, one of the most interesting is the Al doped MgxZn1−xO films for their electrical properties that make it very attracting for solar cell application. In this work, the Mg distribution in Al doped MgxZn1−xO films was investigated in order to find a reliable methods to determine Mg distribution. In particular, X‐ray diffraction, Auger electron spectroscopy and time of flight secondary ion mass spectrometry were used to characterize the film. Time of flight secondary ion mass spectrometry MCs+ results appear to be the most promising analytical technique. Copyright © 2014 John Wiley & Sons, Ltd.
Continuous sequential boundaries for vaccine safety surveillance
Authors: Li Rongxia , Stewart Brock , Weintraub Eric , McNeil Michael M.
Published: April 2014

Various recently developed sequential methods have been used to detect signals for post‐marketing surveillance in drug and vaccine safety. Among these, the maximized sequential probability ratio test (MaxSPRT) has been used to detect elevated risks of adverse events following vaccination using large healthcare databases. However, a limitation of MaxSPRT is that it only provides a time‐invariant flat boundary. In this study, we propose the use of time‐varying boundaries for controlling how type I error is distributed throughout the surveillance period. This is especially useful in two scenarios: (i) when we desire generally larger sample sizes before a signal is generated, for example, when early adopters are not representative of the larger population; and (ii) when it is desired for a signal to be generated as early as possible, for example, when the adverse event is considered rare but serious. We consider four specific time‐varying boundaries (which we call critical value functions), and we study their statistical power and average time to signal detection. The methodology we present here can be viewed as a generalization or flexible extension of MaxSPRT. Published 2014. This article is a US Government work and is in the public domain in the USA.
Strategy tools‐in‐use: A framework for understanding “technologies of rationality” in practice
Authors: Jarzabkowski Paula , Kaplan Sarah
Published: April 2014

In response to critiques of strategy tools as unhelpful or potentially dangerous for organizations, we suggest casting a sociological eye on how tools are actually mobilized by strategy makers. In conceptualizing strategy tools as tools‐in‐use, we offer a framework for examining the ways that the affordances of strategy tools and the agency of strategy makers interact to shape how and when tools are selected and applied. Further, rather than evaluating the correct or incorrect use of tools, we highlight the variety of outcomes that result, not just for organizations but also for the tools and the individuals who use them. We illustrate this framework with a vignette and propose an agenda and methodological approaches for further scholarship on the use of strategy tools. Copyright © 2014 John Wiley & Sons, Ltd.
Re: Which factors are associated with trainees' confidence in performing obstetric and gynecological ultrasound examinations? M. G. Tolsgaard, M. B. Rasmussen, C. Tappert, M. Sundler, J. L. Sorensen, B. Ottesen, C. Ringsted and A. Tabor. Ultrasound Obstet Gynecol 2014; 43: 444–451
Authors: Gonçalves L. F.
Published: April 2014

Linked Comment: Ultrasound Obstet Gynecol 2014; 43: 444–451
Re: Detection of submicroscopic chromosomal aberrations by array‐based comparative genomic hybridization in fetuses with congenital heart disease. Y. Yan, Q. Wu, L. Zhang, X. Wang, S. Dan, D. Deng, L. Sun, L. Yao, Y. Ma and L. Wang. Ultrasound Obstet Gynecol 2014; 43: 404–412
Authors: de Wit M. C.
Published: April 2014

Linked Comment: Ultrasound Obstet Gynecol 2014; 43: 404–412
Physicochemical Properties Improvement of Soy Protein Using Divalent Ions During a Two‐Step Fractionation Process
Authors: Wu Na‐Na , Zheng Er‐Li , Tan Bin , Teng Zi , Yang Xiao‐Quan , Gao Zhi‐Ming
Published: April 2014

This study proposed a two‐step fractionation (TSF) method with the addition of divalent ions to produce a soy protein with lower contents of lipophilic proteins and polar lipids (less‐LP SPI). Flavor volatiles profiles and some functional properties of less‐LP SPI were compared with soy protein prepared from conventional acid precipitated methods (APP). Protein composition and thermal behavior analysis indicated that less‐LP SPI prepared with the addition of 10 mM Ca2+ during TSF process contained less lipophilic proteins and less denatured proteins. Gas chromatography–mass spectrometry analysis showed that the flavor volatiles content of less‐LP SPI was significantly lower than that of APP (p < 0.05). The emulsifying stability of less‐LP SPI was improved in comparison to that of APP (p < 0.05), as indicated by a less significant change in the creaming index and particle size (after 14 and 30 days of storage) of the emulsion prepared with the former than with the latter. Less‐LP SPI had a similar or slightly lower water solubility compared to APP, but it possessed a higher protein content and a lower lipid level. These improvements in the properties of less‐LP SPI might be due to the removal of lipophilic proteins and polar lipids by the divalent ions during the TSF process.
Aerobic cervical bacteriology and antibiotic sensitivity patterns in patients with advanced cervical cancer before and after radiotherapy at a national referral hospital in Uganda
Authors: Mubangizi Louis , Namusoke Fatuma , Mutyaba Twaha
Published: April 2014

Objective

To determine prevalent aerobic cervical bacteria and sensitivity to commonly used antibiotics in patients with advanced cervical cancer before and after 4 weeks of external beam radiotherapy (EBRT).

Methods

Cervical swabs were collected prior to the initial radiation dose and after 4 weeks of radiotherapy at Mulago Hospital. Aerobic culture was performed on blood agar, chocolate agar, and MacConkey agar, and incubated at 35–37 ° for 24–48 hours. Isolates were identified using colonial morphology, Gram staining, and biochemical analysis. Sensitivity testing was performed via Kirby–Bauer disk diffusion and dilution. Differences in the proportions of bacteria isolated before and after radiotherapy were compared. Paired t test was used to obtain differences in sensitivity before and after radiotherapy.

Results

Normal flora increased significantly after EBRT (P = 0.02). There was no significant change in overall proportion of positive cultures. Sensitivity to commonly used antibiotics improved (P = 0.05) and resistance significantly decreased (P = 0.005). Significant differences were seen mainly with ciprofloxacin, ceftriaxone, and gentamicin.

Conclusion

Four weeks of EBRT did not sterilize the cervix but resulted in an increase in normal flora. Radiotherapy appeared to reduce resistance to commonly used antibiotics. Sensitivity to chloramphenicol was higher than for the more commonly used antibiotics.
Interleukin‐23 and its correlation with disease activity, joint damage, and functional disability in rheumatoid arthritis
Authors: Dalila Adnan Siti , Mohd Said Mohd Shahrir , Shaharir Syahrul Sazliyana , Asrul Abdul Wahab , Low Soo Fin , Shamsul Azhar Shah , Sakthiswary Rajalingham
Published: April 2014

The purpose of this study was to compare the serum interleukin (IL)‐23 levels between rheumatoid arthritis (RA) patients and healthy controls and to determine the correlation of IL‐23 levels with disease activity, joint damage and functional disability in RA. Serum samples were obtained from 45 patients with RA and 45 healthy controls. The enzyme‐linked immunosorbent assay method was used for quantitative analysis of IL‐23. All the RA patients were assessed for disease activity based on the 28‐joint disease activity score, joint damage based on modified Sharp score, and functional ability using the Health Assessment Questionnaire–Disability Index. The mean serum IL‐23 level was much higher among the RA patients (24.50 ± 13.98 pg/mL) compared to the controls (5.98 ± 3.40 pg/mL;p < 0.01). There was a significant positive relationship between IL‐23 levels and disease activity and questionnaire scores (p = 0.003 and 0.020, respectively). On logistic regression analysis, IL‐23 levels were significantly higher in patients with moderate to high disease activity (p = 0.008, odds ratio = 1.073, 95% confidence interval = 1.019–1.130) and patients with significant functional disability (p = 0.008, odds ratio = 1.085, 95% confidence interval = 1.021–1.153). RA patients have significantly higher levels of serum IL‐23. The IL‐23 levels correlate well with disease activity and functional disability but not with radiographic joint damage.
Review of the current status of fast ignition research at the IAPCM
Authors: Cai Hong-bo , Wu Si-zhong , Wu Jun-feng , Chen Mo , Zhang Hua , He Min-qing , Cao Li-hua , Zhou Cang-tao , Zhu Shao-ping , He Xian-tu
Published: April 2014

We review the present status and future prospects of fast ignition (FI) research of the theoretical group at the IAPCM (Institute of Applied Physics and Computational Mathematics, Beijing) as a part of the inertial confinement fusion project. Since the approval of the FI project at the IAPCM, we have devoted our efforts to improving the integrated codes for FI and designing advanced targets together with the experimental group. Recent FI experiments [K. U. Akli et al., Phys. Rev. E 86, 065402 (2012)] showed that the petawatt laser beam energy was not efficiently converted into the compressed core because of the beam divergence of relativistic electron beams. The coupling efficiency can be improved in three ways: (1) using a cone–wire-in-shell advanced target to enhance the transport efficiency, (2) using external magnetic fields to collimate fast electrons, and (3) reducing the prepulse level of the petawatt laser beam. The integrated codes for FI, named ICFI, including a radiation hydrodynamic code, a particle-in-cell (PIC) simulation code, and a hybrid fluid–PIC code, have been developed to design this advanced target at the IAPCM. The Shenguang-II upgraded laser facility has been constructed for FI research; it consists of eight beams (in total $24~ {\rm kJ}/3\omega $, 3 ns) for implosion compression, and a heating laser beam (0.5–1 kJ, 3–5 ps) for generating the relativistic electron beam. A fully integrated FI experiment is scheduled for the 2014 project.
Steady turbulent density currents on a slope in a rotating fluid
Authors: Manucharyan G. E. , Moon W. , Sévellec F. , Wells A. J. , Zhong J.-Q. , Wettlaufer J. S.
Published: April 2014

We consider the dynamics of actively entraining turbulent density currents on a conical sloping surface in a rotating fluid. A theoretical plume model is developed to describe both axisymmetric flow and single-stream currents of finite angular extent. An analytical solution is derived for flow dominated by the initial buoyancy flux and with a constant entrainment ratio, which serves as an attractor for solutions with alternative initial conditions where the initial fluxes of mass and momentum are non-negligible. The solutions indicate that the downslope propagation of the current halts at a critical level where there is purely azimuthal flow, and the boundary layer approximation breaks down. Observations from a set of laboratory experiments are consistent with the dynamics predicted by the model, with the flow approaching a critical level. Interpretation in terms of the theory yields an entrainment coefficient $E\propto 1/\Omega $ where the rotation rate is $\Omega $. We also derive a corresponding theory for density currents from a line source of buoyancy on a planar slope. Our theoretical models provide a framework for designing and interpreting laboratory studies of turbulent entrainment in rotating dense flows on slopes and understanding their implications in geophysical flows.
Wealth, Consumerism, and Culture among the Artisans of Göppingen: Dynamism and Tradition in an Eighteenth-Century Hometown
Authors: Frey Dennis A.
Published: April 2014

April 21, 1771, brought unusual weather conditions, namely a springtime blizzard, to the Swabian town of Göppingen. We know this because the worsted-wool weaver Ernst Jacob Vayhinger wrote about it in a chronicle that he kept from 1756 to 1784. His exact words were, “The weather is also quite something. I have a barometer, which indicates the clearest weather today, and yet it is snowing so badly. The same thing happened a year ago. As the upper wind brought rain, it [the barometer] was instead showing nice conditions, and the rain was freezing cold.” While the vivid description of inclement weather certainly catches the eye, the presence of a barometer in this weaver's household in 1771 stands out even more. In fact, this weather-based technology was barely a century old in the latter half of the eighteenth century, having been invented by Evangelista Torricelli, an Italian mathematician, in 1643. To be sure, Vayhinger's malfunctioning barometer was almost certainly a water-filled glass instrument rather than the more precise mercury-based instruments of early-modern natural philosophers, but what matters here is that Vayhinger had a relatively new, ornamental wall hanging that indicated an awareness of new scientific principles. And, as this article will show, he was not at all the only one to acquire such novelties in this hometown full ofHandwerker(artisans).
Approaches to the detection of very small, common, and easily missed outbreaks that together contribute substantially to human Cryptosporidium infection
Authors: BRIGGS A. D. M. , BOXALL N. S. , VAN SANTEN D. , CHALMERS R. M. , McCARTHY N. D.
Published: April 2014

Water supply-associated cryptosporidiosis outbreaks have decreased in England since the application of risk reduction measures to public water supplies. We hypothesized that smaller outbreaks were occurring which could be better detected by enhanced surveillance. Rolling analysis of detailed questionnaire data was applied prospectively in a population of 2·2 million in the south of England in 2009 and 2010. Detection of spatiotemporal clusters using SaTScan was later undertaken retrospectively. Together these approaches identified eight outbreaks, compared to an expectation of less than one based on national surveillance data. These outbreaks were small and associated with swimming pool use or, less commonly, direct (e.g. petting-farm) contact with animals. These findings suggest that frequent small-scale transmission in swimming pools is an important contributor to disease burden. Identification of swimming pool-level risk factors may inform preventative measures. These findings and the approaches described may be applicable to many other populations and to some other diseases.
Going Places: Recent Histories of European Tourism
Authors: WILLIAMS TOM
Published: April 2014

Writing in 1997, Britain's leading historian of tourism John K. Walton lamented that ‘tourism has not been accepted into the charmed circle of acceptable themes in European history’. While it would be premature to suggest that tourism has now been welcomed into this select inner circle on equal terms with more traditional fields of research, there is nevertheless much for historians of tourism to be positive about. Over the course of the last two decades, a growing body of scholarship has demonstrated not only that tourism needs to be taken seriously as a factor that shaped the modern world but also that the study of tourist practices has the potential to shed new light on seemingly familiar historical issues and debates. The complex range of factors that have enabled and hindered tourism's rise towards respectability within historical studies have been discussed in detail elsewhere by prominent exponents of the genre and will not be reiterated here. However, three flourishing and interconnected fields of historical inquiry, to which historians of tourism are making valuable contributions, deserve particular mention. Each of the works discussed below can be situated broadly within these three historiographical trends.
‘Modernity’ and the Making of Social Order in Twentieth-Century Europe
Authors: SWEENEY DENNIS
Published: April 2014

It is hard not to be struck by the continuing interest in the concept of ‘modernity’ or ‘the modern’ for making sense of the economic, cultural and political transformations of twentieth-century Europe. Seemingly laid to rest by the early 1980s for its association with modernisation theory, modernity as a concept was revived during the late 1980s and 1990s largely by European historians working on countries, especially Germany and Russia, with nineteenth- and twentieth-century histories that modernisation theorists deemed models of developmental backwardness or case studies in the failure to modernise and its consequences. But, like its striking re-appearance in scholarship on those areas of the world – especially Asia and Africa – written off as the most irredeemably un-modern or ‘traditional’ by modernisation theorists, this renewed interest in modernity derives from very different interventions in post-structuralist theory and cultural and postcolonial studies, which have generated new definitions, and critiques ‘modernity’ and its ‘dark side’ from the vantage point of ‘postmodernity’.
TEM Investigation of Deformation Mechanisms in FeMnCrCN TWIP Steel
Authors: Wittig J.E. , Pierce D.T. , Mosecker L. , Saeed-Akbari A. , Beigmohamadi M. , Mayer J.
Published: April 2014

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.
Lokale Abhängigkeit von Items im TestDaF-Leseverstehen
Authors: Eckes Thomas
Published: April 2014

Testlets sind Teilmengen von Testitems, die sich auf denselben Input beziehen. Testverfahren, die Testlets enthalten, sind in der pädagogisch-psychologischen Diagnostik weit verbreitet. Mit der Verwendung von Testlets ist allerdings ein ernstes psychometrisches Problem verbunden: Items, die einem Testlet angehören, verletzen die grundlegende Annahme der lokalen Unabhängigkeit. Gegenstand dieser Arbeit waren Einflüsse von Testlets im Prüfungsteil Leseverstehen des Tests Deutsch als Fremdsprache (TestDaF). Anhand eines Modells der Testlet-Response-Theorie ( Wainer, Bradlow & Wang, 2007 ) wurden Antworten von Teilnehmenden (N = 2 859) auf 30 Items, aufgeteilt auf drei Lesetexte (Testlets) mit je 10 Items, analysiert. Im ersten Lesetext fielen die Testlet-Effekte deutlich aus; in den beiden anderen Lesetexten ergaben sich nur schwache Effekte. Weitere Analysen zeigten, dass die Vernachlässigung der Testlet-Effekte eine erhöhte Schätzung der Testreliabilität sowie abweichende Schätzungen der Itemtrennschärfe und Itemschwierigkeit zur Folge hatte. Implikationen der Ergebnisse für die Entwicklung, Analyse und Evaluation testlet-basierter Testverfahren werden diskutiert.
Dressed-photon–phonon (DPP)-assisted visible- and infrared-light water splitting
Authors: Yatsui Takashi , Imoto Tsubasa , Mochizuki Takahiro , Kitamura Kokoro , Kawazoe Tadashi
Published: April 2014

A dressed-phonon–phonon (DPP) assisted photocatalyst reaction was carried out to increase the visible light responsibility, where the photon energy of the radiation, which ranged from visible to infrared light is less than band gap energy of the photocatalyst (ZnO, 3.3 eV). The dependence of the photocurrent on excitation power indicated that two-step excitation occurred in DPP-assisted process. A cathodoluminescence measurement also supported the conclusion that the visible- and infrared-light excitation originated from DPP excitation, not from defect states in the ZnO nanorod photocatalyst.
Highly connected hierarchical textured TiO2spheres as photoanodes for dye-sensitized solar cells
Authors: Lin Jianjian , Nattestad Andrew , Yu Hua , Bai Yang , Wang Lianzhou , Dou Shi Xue , Kim Jung Ho
Published: April 2014

Highly connected hierarchical textured TiO2spheres, composed of high aspect-ratio nanosheets, gave high conversion efficiency in dye-sensitized solar cells.
Label-free identification and characterization of murine hair follicle stem cells located in thin tissue sections with Raman micro-spectroscopy
Authors: Tsai Tsung-Hua , Short Michael A. , McLean David I. , Zeng Haishan , McElwee Kevin , Lui Harvey
Published: April 2014

Stem cells offer tremendous opportunities for regenerative medicine.
Determination of methylarginines in infant plasma by CE-LIF
Authors: Linz Thomas H. , Lunte Susan M.
Published: April 2014

Novel sample preparation and CE-LIF separation methods are described that can be implemented to quantify biomarkers of the nitric oxide metabolic pathway in plasma samples from critically ill infants.
Unusual coordination of tetrylenes to molybdenum carbonyl fragments
Authors: Lips Felicitas , Queen Joshua D. , Fettinger James C. , Power Philip P.
Published: April 2014

Reactions of tetrylenes Ge(SArMe6)2and Sn(SArMe6)2with [Mo(CO)4(NBD)] (NBD = bicyclo[2.2.1]hepta-2,5-diene (norbornadiene)) yield compounds with unusual coordination of the molybdenum carbonyl fragment to the sulfur atoms of the thiolato ligands.
A concise [C+NC+CC] coupling-enabled synthesis of kaitocephalin
Authors: Garner Philip , Weerasinghe Laksiri , Van Houten Ian , Hu Jieyu
Published: April 2014

An efficient synthesis of the iGluR antagonist kaitocephalin is reported, employing an asymmetric [C+NC+CC] reaction in the key step.
A novel fullerene oxide functionalized silica composite as stationary phase for high performance liquid chromatography
Authors: Liu Houmei , Guo Yong , Wang Xusheng , Liang Xiaojing , Liu Xia , Jiang Shengxiang
Published: April 2014

An FO/SiO2 composite was successfully synthesized and revealed good separation for four kinds of hydrophilic compounds in HILIC.
Mussel-inspired modification of a polymer membrane for ultra-high water permeability and oil-in-water emulsion separation
Authors: Yang Hao-Cheng , Liao Kun-Jian , Huang He , Wu Qing-Yun , Wan Ling-Shu , Xu Zhi-Kang
Published: April 2014

Polydopamine/polyethyleneimine-decorated membranes were fabricated with excellent surface hydrophilicity and high water permeability for oil/water emulsion separation under atmospheric pressure.
Design and optical investigations of a spironaphthoxazine/polyoxometalate/spiropyran triad
Authors: Saad Ali , Oms Olivier , Marrot Jérôme , Dolbecq Anne , Hakouk Khadija , El Bekkachi Houda , Jobic Stéphane , Deniard Philippe , Dessapt Rémi , Garrot Damien , Boukheddaden Kamel , Liu Rongji , Zhang Guangjin , Keita Bineta , Mialane Pierre
Published: April 2014

The richness of the optical properties of covalent polyoxometalate/organic chromophores compounds is reported.
Human pleural B-cells regulate IFN-γ production by local T-cells and NK cells in aMycobacterium tuberculosis-induced delayed hypersensitivity reaction
Authors: Schierloh Pablo , Landoni Verónica , Balboa Luciana , Musella Rosa M. , Castagnino Jorge , Moraña Eduardo , de Casado Graciela C. , Palmero Domingo , Sasiain María C.
Published: April 2014

DTH (delayed type hypersensitivity) reactions are secondary cellular immune responses that appear 24–72 h after antigen exposure. Tuberculous pleurisy is a common manifestation of extrapulmonary TB (tuberculosis) and is considered a human model of Th1-mediated DTH. In order to identify functional cross-talk among cellular populations sited in this inflammatory microenvironment, we analysed phenotypic and functional features of human B-cells isolated from the PF (pleural fluid) of TB patients. Freshly isolated PF-B-cells displayed a lower expression of CD20, CD1d and HLA-DR, and a higher expression of CD95, CD38, CD25, CXCR3 (CXC chemokine receptor 3) and CXCR4 (CXC chemokine receptor 4) than their PB (peripheral blood) counterparts, suggesting a non-classical in situ activation. Although memory PF-T-cell frequencies were increased, the frequencies of memory PF-B-cells were not. We demonstrated that, upon stimulation with γ-irradiated M. tuberculosis, mycobacterially secreted proteins or a lectin mitogen, PF-B-cells had a strong activation and produced IL-10 by a mechanism that was dependent on bystander activation of CD19− PF cells. Besides, within PF cells, B-cells diminished in vitro M. tuberculosis-induced IFN (interferon)-γ production by T-cells and NK (natural killer) cells in an IL-10-dependent manner. Finally, we found that the lower the frequency of B-cells, the higher the ratio of IFN-γ/IL-10 within PF. Thus our results suggest that B-cells can regulate a human DTH reaction induced by M. tuberculosis.
Spin dependent transport properties of Mn-Ga/MgO/Mn-Ga magnetic tunnel junctions with metal(Mg, Co, Cr) insertion layer
Authors: Liang S. H. , Tao L. L. , Liu D. P. , Lu Y. , Han X. F.
Published: April 2014

We report a first principles theoretical investigation of spin polarized quantum transport in Mn2Ga/MgO/Mn2Ga and Mn3Ga/MgO/Mn3Ga magnetic tunneling junctions (MTJs) with the consideration of metal(Mg, Co, Cr) insertion layer effect. By changing the concentration of Mn, our calculation shows a considerable disparity in transport properties: A tunneling magnetoresistance (TMR) ratio of 852% was obtained for Mn2Ga-based MTJs, however, only a 5% TMR ratio for Mn3Ga-based MTJs. In addition, the influence of insertion layer has been considered in our calculation. We found the Co insertion layer can increase the TMR of Mn2Ga-based MTJ to 904%; however, the Cr insertion layer can decrease the TMR by 668%; A negative TMR ratio can be obtained with Mg insertion layer. Our work gives a comprehensive understanding of the influence of different insertion layer in Mn-Ga based MTJs. It is proved that, due to the transmission can be modulated by the interfacial electronic structure of insertion, the magnetoresistance ratio of Mn2Ga/MgO/Mn2Ga MTJ can be improved by inserting Co layer.
Synchronization of spin torque nano-oscillators through dipolar interactions
Authors: Chen Hao-Hsuan , Lee Ching-Ming , Wu Jong-Ching , Horng Lance , Chang Ching-Ray , Chang Jui-Hang
Published: April 2014

In an array of spin-torque nano-oscillators (STNOs) that combine a perpendicular polarized fixed layer with strong in-plane anisotropy in the free layers, magnetic dipolar interactions can effectively phase-lock the array, thus further enhancing the power of the output microwave signals. We perform a qualitative analysis of the synchronization of an array based on the Landau-Lifshitz-Gilbert equation, with a spin-transfer torque that assumes strong in-plane anisotropy. Finally, we present the numerical results for four coupled STNOs to provide further evidence for the proposed theory.
Stokes' theorem, gauge symmetry and the time-dependent Aharonov-Bohm effect
Authors: Macdougall James , Singleton Douglas
Published: April 2014

Stokes' theorem is investigated in the context of the time-dependent Aharonov-Bohm effect—the two-slit quantum interference experiment with a time varying solenoid between the slits. The time varying solenoid produces an electric field which leads to an additional phase shift which is found to exactly cancel the time-dependent part of the usual magnetic Aharonov-Bohm phase shift. This electric field arises from a combination of a non-single valued scalar potential and/or a 3-vector potential. The gauge transformation which leads to the scalar and 3-vector potentials for the electric field is non-single valued. This feature is connected with the non-simply connected topology of the Aharonov-Bohm set-up. The non-single valued nature of the gauge transformation function has interesting consequences for the 4-dimensional Stokes' theorem for the time-dependent Aharonov-Bohm effect. An experimental test of these conclusions is proposed.
Hermite polynomials and quasi-classical asymptotics
Authors: Ali S. Twareque , Engliš Miroslav
Published: April 2014

We study an unorthodox variant of the Berezin-Toeplitz type of quantization scheme, on a reproducing kernel Hilbert space generated by the real Hermite polynomials and work out the associated quasi-classical asymptotics.
Efficiency analysis of diffusion on T-fractals in the sense of random walks
Authors: Peng Junhao , Xu Guoai
Published: April 2014

Efficiently controlling the diffusion process is crucial in the study of diffusion problem in complex systems. In the sense of random walks with a single trap, mean trapping time (MTT) and mean diffusing time (MDT) are good measures of trapping efficiency and diffusion efficiency, respectively. They both vary with the location of the node. In this paper, we analyze the effects of node's location on trapping efficiency and diffusion efficiency of T-fractals measured by MTT and MDT. First, we provide methods to calculate the MTT for any target node and the MDT for any source node of T-fractals. The methods can also be used to calculate the mean first-passage time between any pair of nodes. Then, using the MTT and the MDT as the measure of trapping efficiency and diffusion efficiency, respectively, we compare the trapping efficiency and diffusion efficiency among all nodes of T-fractal and find the best (or worst) trapping sites and the best (or worst) diffusing sites. Our results show that the hub node of T-fractal is the best trapping site, but it is also the worst diffusing site; and that the three boundary nodes are the worst trapping sites, but they are also the best diffusing sites. Comparing the maximum of MTT and MDT with their minimums, we find that the maximum of MTT is almost 6 times of the minimum of MTT and the maximum of MDT is almost equal to the minimum for MDT. Thus, the location of target node has large effect on the trapping efficiency, but the location of source node almost has no effect on diffusion efficiency. We also simulate random walks on T-fractals, whose results are consistent with the derived results.
Tuning the electronic structure of SrTiO3/SrFeO3−x superlattices via composition and vacancy control
Authors: Berger Robert F. , Broberg Daniel P. , Neaton Jeffrey B.
Published: April 2014

Using density functional theory-based calculations, we explore the effects of oxygen vacancies and epitaxial layering on the atomic, magnetic, and electronic structure of (SrTiO3)n(SrFeO3−x)1 superlattices. While structures without oxygen vacancies (x = 0) possess small or non-existent band gaps and ferromagnetic ordering in their iron layers, those with large vacancy concentrations (x = 0.5) have much larger gaps and antiferromagnetic ordering. Though the computed gaps depend numerically on the delicate energetic balance of vacancy ordering and on the value of Hubbard \documentclass[12pt]{minimal}\begin{document}$U_{\textrm {eff}}$\end{document}U eff used in the calculations, we demonstrate that changes in layering can tune the band gaps of these superlattices below that of SrTiO3 (3.2 eV) by raising their valence band maxima. This suggests the possibility that these superlattices could absorb in the solar spectrum, and could serve as water-splitting photocatalysts.
Brillouin light scattering study of spin waves in NiFe/Co exchange spring bilayer films
Authors: Haldar Arabinda , Banerjee Chandrima , Laha Pinaki , Barman Anjan
Published: April 2014

Spin waves are investigated in Permalloy(Ni80Fe20)/Cobalt(Co) exchange spring bilayer thin films using Brillouin light scattering (BLS) experiment. The magnetic hysteresis loops measured by magneto-optical Kerr effect show a monotonic decrease in coercivity of the bilayer films with increasing Py thickness. BLS study shows two distinct modes, which are modelled as Damon-Eshbach and perpendicular standing wave modes. Linewidths of the frequency peaks are found to increase significantly with decreasing Py layer thickness. Interfacial roughness causes to fluctuate exchange coupling at the nanoscale regimes and the effect is stronger for thinner Py films. A quantitative analysis of the magnon linewidths shows the presence of strong local exchange coupling field which is much larger compared to macroscopic exchange field.
Second harmonic generation from metamaterials strongly coupled to intersubband transitions in quantum wells
Authors: Campione Salvatore , Benz Alexander , Sinclair Michael B. , Capolino Filippo , Brener Igal
Published: April 2014

We theoretically analyze the second harmonic generation capacity of two-dimensional periodic metamaterials comprising sub-wavelength resonators strongly coupled to intersubband transitions in quantum wells (QWs) at mid-infrared frequencies. The metamaterial is designed to support a fundamental resonance at ∼30 THz and an orthogonally polarized resonance at the second harmonic frequency (∼60 THz), while the asymmetric quantum well structure is designed to provide a large second order susceptibility. Upon continuous wave illumination at the fundamental frequency we observe second harmonic signals in both the forward and backward directions, with the forward efficiency being larger. We calculate the overall second harmonic conversion efficiency of the forward wave to be ∼1.3 × 10−2 W/W2—a remarkably large value, given the deep sub-wavelength dimensions of the QW structure (about 1/15th of the free space wavelength of 10 μm). The results shown in this Letter provide a strategy for designing easily fabricated sources across the entire infrared spectrum through proper choice of QW and resonator designs.
Symmetry breaking induces band gaps in periodic piezoelectric plates
Authors: Huang Y. , Wang H. M. , Chen W. Q.
Published: April 2014

In this study, we propose a phononic plate model with periodically corrugated surfaces and investigate the propagation behavior of Lamb waves in it. In contrast to the traditional phononic crystals which are composed of isotropic materials, the electroelastic coupling is taken into account in this investigation. Based on the Floquet's theorem, the Lamb wave solution is expanded in the series form of spatially harmonic plane waves. Band structures in the first Brillouin zone are presented graphically. The band gaps can be tuned by adjusting the structural parameters. We find that the structural symmetry of the plate has significant influence on the band gap properties. The symmetry breaking of the plate structure leads to more band gaps appearing in the first Brillouin zone. Moreover, the band gaps are also sensitive to the symmetry of the electric boundary conditions, which provides a feasible way to electrically control the acoustic band structure.
Comparative electron paramagnetic resonance investigation of reduced graphene oxide and carbon nanotubes with different chemical functionalities for quantum dot attachment
Authors: Pham Chuyen V. , Krueger Michael , Eck Michael , Weber Stefan , Erdem Emre
Published: April 2014

Electron paramagnetic resonance (EPR) spectroscopy has been applied to different chemically treated reduced graphene oxide (rGO) and multiwalled carbon nanotubes (CNTs). A narrow EPR signal is visible at g = 2.0029 in both GO and CNT-Oxide from carbon-related dangling bonds. EPR signals became broader and of lower intensity after oxygen-containing functionalities were reduced and partially transformed into thiol groups to obtain thiol-functionalized reduced GO (TrGO) and thiol-functionalized CNT (CNT-SH), respectively. Additionally, EPR investigation of CdSe quantum dot-TrGO hybrid material reveals complete quenching of the TrGO EPR signal due to direct chemical attachment and electronic coupling. Our work confirms that EPR is a suitable tool to detect spin density changes in different functionalized nanocarbon materials and can contribute to improved understanding of electronic coupling effects in nanocarbon-nanoparticle hybrid nano-composites promising for various electronic and optoelectronic applications.
Transient and persistent current induced conductivity changes in GaAs/AlGaAs high-electron-mobility transistors
Authors: Schulte-Braucks Christian , Valentin Sascha R. , Ludwig Arne , Wieck Andreas D.
Published: April 2014

We report the observation of a current induced change of the low temperature conductivity of two-dimensional electron gases in GaAs/AlGaAs-high-electron-mobility transistors. By applying voltage pulses on the ohmic contacts of a Hall bar-mesa-structure, both sheet-carrier-density n2D and electron mobility μ are decreased. At temperatures below 50 K, a persistent change combined with a partial transient recovery of n2D has been observed. The transient behaviour and the lateral spreading of the effect are studied. Moreover, a temperature dependent investigation has been done in order to get insight into the addressed defect energy levels. A model based on the phenomenology of the effect is proposed. The observed effect is not a permanent degradation as the original carrier concentration can be restored by warming up the sample to room temperature and recooling it.
Feasibility of Schottky diode as selector for bipolar-type resistive random access memory applications
Authors: Li Yingtao , Gong Qingchun , Jiang Xinyu
Published: April 2014

The feasibility of Schottky diode as selector has been investigated for possible application in bipolar-type resistive random access memory (RRAM) devices. In order to evaluate the feasibility of Schottky diode as selector for bipolar-type RRAM applications, a full device simulation has been performed utilizing a Schottky diode + bipolar-type RRAM structure (1SD-1R). On the other hand, we confirmed its successful operation under experimental results with Ni/TiOx/W Schottky diode + Pt/HfO2/Cu bipolar-type RRAM structure. Furthermore, by applying a lower Set voltage in the 1SD-1R structure device, the Reset current and Reset voltage are found to decrease due to the reduced compliance current. Such dependence provides the possibility of lower power consumption in the 1SD-1R structure device.