bluuebunny/crossref_metadata_2025 huggingface dataset:
The signal game: Missions and playground to motivate vocational education students toward periodic signals
Authors: Marzo Asier
Published: April 2015

Vocational Education is a modality of regulated learning that emphasizes practical and applied skills over theoretical approaches. Nevertheless, some theoretical subjects are contained in the program. These subjects are not well perceived by the students, even when the concepts taught in them represent physically perceptible phenomena. The Signal Game represents periodical signals as audible sounds to help students learning concepts such as frequency, amplitude and summation, or multiplexing of signals. To play the game, the students can drag and wire blocks visually and thus it does not require a strong theoretical background. The game allows the users to play through sequential missions. Thereby, the student can learn and assimilate the concepts gradually. The other game mode is the playground, in it the students have all the possibilities enabled. A user study revealed that the game increased intrinsic motivation and that the students acquired applicable concepts about signal theory. © 2015 Wiley Periodicals, Inc. Comput. Appl. Eng. Educ. Comput Appl Eng Educ 23:771–777, 2015; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21649
Both serum 25‐hydroxyvitamin D and calcium levels may increase the risk of incident prostate cancer in Caribbean men of African ancestry
Authors: Jackson Maria D. , Tulloch‐Reid Marshall K. , Lindsay Carole M. , Smith Garrett , Bennett Franklyn I. , McFarlane‐Anderson Norma , Aiken William , Coard Kathleen C. M.
Published: April 2015

Circulating 25‐hydroxyvitamin D [25(OH)D] concentrations have been associated with both higher and lower risk of prostate cancer (PCa), whereas elevated levels of circulating calcium has been related to higher risks. However, there are few studies that account for effects of both calcium and 25(OH)D concentrations on incident PCa in a black population. We examined these relationships in a case–control study of men 40–80 years old with newly diagnosed, histologically confirmed PCa in Jamaica, a tropical country. Mean serum calcium concentrations was higher among cases (2.32 ± 0.19 mmol/L) than controls, (2.27 ± 0.30 mmol/L) (P = 0.023) however, there were no differences in 25(OH)D by cancer status (cases, 33.67 ± 12.71 ng/mL; controls (32.25 ± 12.59 ng/mL). Serum calcium was not correlated with 25(OH)D (partial correlation: r, 0.06; P = 0.287). Multivariable‐adjusted models showed a positive linear relationship between PCa and serum calcium (OR, 1.12; CI, 1.00–1.25 per 0.1 nmol/L). Serum 25(OH)D concentration also showed a positive association with PCa (OR, 1.23; CI, 1.01–1.49 per 10 ng/mL). The odds of PCa in men with serum 25(OH)D tertile 2 was OR, 2.18; CI, 1.04–4.43 and OR, 2.47 CI, 1.20–4.90 for tertile 3 (Ptrend = 0.013). Dietary intakes of calcium showed no relationship with PCa. Despite the strong relationship between serum calcium and vitamin D the mechanism by which each affects prostate cancer risk in men of African ancestry needs additional investigation.
Persistent topology for cryo‐EM data analysis
Authors: Xia Kelin , Wei Guo‐Wei
Published: April 2015

In this work, we introduce persistent homology for the analysis of cryo‐electron microscopy (cryo‐EM) density maps. We identify the topological fingerprint or topological signature of noise, which is widespread in cryo‐EM data. For low signal‐to‐noise ratio (SNR) volumetric data, intrinsic topological features of biomolecular structures are indistinguishable from noise. To remove noise, we employ geometric flows that are found to preserve the intrinsic topological fingerprints of cryo‐EM structures and diminish the topological signature of noise. In particular, persistent homology enables us to visualize the gradual separation of the topological fingerprints of cryo‐EM structures from those of noise during the denoising process, which gives rise to a practical procedure for prescribing a noise threshold to extract cryo‐EM structure information from noise contaminated data after certain iterations of the geometric flow equation. To further demonstrate the utility of persistent homology for cryo‐EM data analysis, we consider a microtubule intermediate structure Electron Microscopy Data (EMD 1129). Three helix models, an alpha‐tubulin monomer model, an alpha‐tubulin and beta‐tubulin model, and an alpha‐tubulin and beta‐tubulin dimer model, are constructed to fit the cryo‐EM data. The least square fitting leads to similarly high correlation coefficients, which indicates that structure determination via optimization is an ill‐posed inverse problem. However, these models have dramatically different topological fingerprints. Especially, linkages or connectivities that discriminate one model from another, play little role in the traditional density fitting or optimization but are very sensitive and crucial to topological fingerprints. The intrinsic topological features of the microtubule data are identified after topological denoising. By a comparison of the topological fingerprints of the original data and those of three models, we found that the third model is topologically favored. The present work offers persistent homology based new strategies for topological denoising and for resolving ill‐posed inverse problems. Copyright © 2015 John Wiley & Sons, Ltd.
Experimental research of effects of different rotation radii on the growth rate of potassium dihydrogen phosphate crystals
Authors: Cheng Min , Kang Daoyuan , Zhang Xiaoli , Yin Huawei , Wang Yuhong
Published: April 2015

Comparing with the traditional concentric rotation method (rotation radius is 0 cm), the effects of different rotation radii on the growth rate of KDP crystals were studied by experimental methods. It was found that with the increase of rotation radius from 0 cm, the growth rate of each direction of crystals first increased and then decreased in a size‐unchanged vessel. The smaller the distance between the crystal and vessel wall, the less the growth rate. This phenomenon was named the “wall collision effect”. Also, the value of growth rate reached a maximum when the rotation radius was about half of its allowable largest value in the size‐unchanged vessel. In addition, an increase of the rotation radius could improve the crystal growth rate under the same linear velocity of crystal movement. Finally, the uniformity of crystal growth has also been analyzed compared with the concentric rotation radius. It was found that the uniformity of crystal growth was best when the rotation radius was half of its allowable maximum value, and it was more conducive to the actual application of KDP crystals.
Outcomes and cost minimisation associated with outpatient parenteral antimicrobial therapy (OPAT) for foot infections in people with diabetes
Authors: Malone Matthew , West Dana , Xuan Wei , Lau Namson S. , Maley Michael , Dickson Hugh G.
Published: April 2015

Objective

To determine clinical outcomes in patients with diabetic foot infections receiving outpatient parenteral antimicrobial therapy (OPAT), to evaluate cost savings from the use of OPAT and to analyse demographic, clinical and laboratory data that may predict OPAT failure.

Research Design and Methodology

A retrospective cohort analysis was conducted between 1 January 2007 and 7 July 2012 at a tertiary referral hospital in metropolitan Sydney. Patients with diabetic foot infection were identified from the outpatient parenteral antimicrobial therapy database. Demographic, clinical, laboratory and operative report data were obtained from patient charts and electronic medical records. Potential cost savings were calculated on the estimated cost of expenditure versus the expected savings. Linear regression was used to explore outcomes associated with outpatient parenteral antimicrobial therapy failure.

Results

Fifty‐nine patients were identified over the 5‐year study period. The outpatient parenteral antimicrobial therapy success rate for diabetic foot infections was 88%. Following the resolution of the primary episode of infection, new infective episodes within the study period were high (n = 26, 44%). Regression analysis of variables for OPAT failure failed to indicate any factors reaching statistical significance. A total of 1569 days were saved by using outpatient parenteral antimicrobial therapy for an estimated total cost saving of $983 645 or $16 672 per patient.

Conclusion

Outpatient intravenous therapy for diabetic foot infections is an effective mode of treatment that can contribute to significant healthcare savings. High re‐infection rates associated with diabetes foot ulceration in this population underline the need for close monitoring and management of these patients in multidisciplinary high‐risk foot setting. Copyright © 2015 John Wiley & Sons, Ltd.
IL‐1β inhibits ILC3 while favoring NK‐cell maturation of umbilical cord blood CD34+ precursors
Authors: Ambrosini Paolo , Loiacono Fabrizio , Conte Romana , Moretta Lorenzo , Vitale Chiara , Mingari Maria Cristina
Published: April 2015

NK cells are innate lymphocytes characterized by the expression of nuclear factor interleukin 3 regulated (NFIL3 or E4BP4), eomesodermin (EOMES) transcription factors (TFs), and by the ability to exert cytolytic activity and release IFN‐γ. In the haploidentical‐hematopoietic stem cell transplantation (haplo‐HSCT) setting, CD34+ donor derived NK cells play a major role in the control of leukemic relapses. Therefore, it is important to better define cytokines that influence NK‐cell differentiation from CD34+ precursors. We analyzed the effects of IL‐1β on NK‐cell differentiation from umbilical cord blood (UCB) CD34+ cells. While IL‐1β inhibited CD161+CD56+ cell proliferation, an increased expression of LFA‐1, CD94/NKG2A, KIRs, and perforin on CD56+ cells was detected. In addition, within the CD161+CD56+IL‐1RI+LFA‐1− cell fraction (representing group 3 innate lymphoid cells, ILC3‐like cells), a significant increase of EOMES, NKp46, and CD94/NKG2A receptors, cytolytic granules, and IFN‐γ was detected. This increase was paralleled by a decrease of related orphan receptors (RORγt) TF, NKp44 expression, and IL‐22 production. These data suggest that IL‐1β inhibits ILC3‐ while favoring NK‐cell maturation. Since in haplo‐HSCT conditioning regimen, infections or residual leukemia cells may induce IL‐1β production, this may influence the NK/ILC3 development from donor‐derived CD34+ precursors.
Tandem Prins Cyclization for the Stereoselective Synthesis of the 4,5‐Diaryl‐hexahydropyrano[3,4‐c]chromene Skeleton of Calyxins I and J
Authors: Reddy Basi V. Subba , Reddy Mittapalli Ramana , Reddy Sama Gopal , Sridhar Balasubramanyan , Kumar Singarapu Kiran
Published: April 2015

A Prins bicyclization strategy for the stereoselective synthesis of trans‐fused hexahydropyrano[3,4‐c]chromene derivatives in good to excellent yields has been developed. The synthetic versatility of this approach has been demonstrated in the synthesis of calyxin I and J analogues. This is the first example of the synthesis of hexahydropyrano[3,4‐c]chromene derivatives from (E)‐3‐[2‐(benzyloxy)phenyl]‐5‐phenylpent‐4‐en‐1‐ol (4b) and aldehydes.
Silver(I)‐Catalyzed Tandem Approach to β‐Oxo Amides
Authors: Vandavasi Jaya Kishore , Hsiao Cheng‐Tien , Hu Wan‐Ping , Boominathan Siva Senthil Kumar , Wang Jeh‐Jeng
Published: April 2015

A facile and efficient AgI‐catalytic approach is reported for the first time to synthesize β‐oxo amides from β‐oxo esters a with broad substrate scope in good to excellent yields. Crossover and in situ NMR studies confirmed that the reaction occurred through a new pathway and not by the traditional condensation reaction. The key advantages of this method are the readily available starting materials, the air‐stable reaction, the simple protocol, and the environmental friendliness.
Total Synthesis of (±)‐8‐Oxo‐erythrinine, (±)‐8‐Oxo‐erythraline, and (±)‐Clivonine
Authors: He Maomao , Qu Chunrong , Ding Bingbing , Chen Hao , Li Yangyan , Qiu Guofu , Hu Xianming , Hong Xuechuan
Published: April 2015

Total syntheses of the erythrina alkaloids (±)‐8‐oxo‐erythrinine and (±)‐8‐oxo‐erythraline have been developed, based on a substrate‐controlled intramolecular 6‐exo‐trig selective radical spirocyclization that establishes the quaternary center of the B‐rings. An improved total synthesis of (±)‐clivonine has also been reported, based on an intramolecular 6‐endo‐trig free‐radical cyclization of a highly functionalized enamide, and a biomimetic ring‐switch of a lycorine‐type intermediate. These endo/exo‐selective sequences enabled us to rapidly assemble two different complex alkaloids from a common building block in an economical fashion.
Validation and comparison of geostatistical and spline models for spatial stream networks
Authors: Rushworth A. M. , Peterson E. E. , Ver Hoef J. M. , Bowman A. W.
Published: April 2015

Scientists need appropriate spatial‐statistical models to account for the unique features of stream network data. Recent advances provide a growing methodological toolbox for modelling these data, but general‐purpose statistical software has only recently emerged, with little information about when to use different approaches. We implemented a simulation study to evaluate and validate geostatistical models that use continuous distances, and penalised spline models that use a finite discrete approximation for stream networks. Data were simulated from the geostatistical model, with performance measured by empirical prediction and fixed effects estimation. We found that both models were comparable in terms of squared error, with a slight advantage for the geostatistical models. Generally, both methods were unbiased and had valid confidence intervals. The most marked differences were found for confidence intervals on fixed‐effect parameter estimates, where, for small sample sizes, the spline models underestimated variance. However, the penalised spline models were always more computationally efficient, which may be important for real‐time prediction and estimation. Thus, decisions about which method to use must be influenced by the size and format of the data set, in addition to the characteristics of the environmental process and the modelling goals. ©2015 The Authors. Environmetrics published by John Wiley & Sons, Ltd.
Spot Market Volatility and Futures Trading: The Pitfalls of Using a Dummy Variable Approach
Authors: Bohl Martin T. , Diesteldorf Jeanne , Salm Christian A. , Wilfling Bernd
Published: April 2015

This study challenges the existing literature examining the impact of the introduction of index futures trading on the volatility of its underlying. To overcome econometric shortcomings of previously published work using the dummy variable approach, we employ a Markov‐switching‐GARCH technique. This approach endogenously identifies distinct volatility regimes rather than modeling an exogenously defined one‐step change in the volatility process. We investigate stock market volatility in France, Germany, Japan, the United Kingdom, and the United States. Our empirical results indicate that index futures trading does neither stabilize nor destabilize the underlying spot market. © 2015 Wiley Periodicals, Inc. Jrl Fut Mark 36:30–45, 2016
Change in therapeutic apheresis practices: Role of continuing medical education (CME)
Authors: Tiwari Aseem Kumar , Dara Ravi C. , Pandey Prashant , Arora Dinesh , Rawat Ganesh , Raina Vimarsh
Published: April 2015

Introduction

American society for apheresis (ASFA) publishes guidelines for therapeutic apheresis (TA) and physicians ordering TA procedures should be aware of the appropriate indications based on scientific evidence. Transfusion Medicine specialists (apheresis physicians) can steer physicians in right direction through CME on right indications, duration of therapy and replacement fluid. Therefore, authors reviewed, collated, and interpreted effect of formal CME interventions.

Materials and Methods

Retrospective study was conducted in a large hospital in India. CME interventions to teach clinical and managerial aspects of TA were conducted in the first quarter of 2012. Sessions involved ASFA guidelines and recommendations for TA. Data was collected and changes in practice related to TA before (March 2010 to December 2011) and after (April 2012 to December 2013) the intervention was analyzed.

Results

Seventy‐three subjects participated in the interventions. Five hundred and eighty‐nine TA procedures were performed during study period; 214 procedures in 49 patients before intervention and 375 procedures in 84 patients after intervention. After intervention there was significant improvement in indications of category I (38.7% vs. 64.3%; P = 0.004), category II (22.5% vs. 16.6%), category III (12.2% vs. 11.9%), and category IV (6.1% vs. 2.4%; P = 0.0001). Significant reduction was seen in procedures not belonging to any category from 20.5% to 4.8% (P = 0.002). Change in practices was also observed in context of duration of therapy and replacement fluid.

Conclusion

CME intervention, based on the 2010 edition of ASFA guidelines for therapeutic apheresis appears to have had a positive impact on physicians TA practices. J. Clin. Apheresis 31:16–21, 2016. © 2015 Wiley Periodicals, Inc.
Hematopoietic progenitor cells collection in pediatric patients with brain tumor
Authors: Spínola Ana , Ferreira Sara , Amado Fátima , Lopes Sérgio , Roncon Susana
Published: April 2015

Aim

To analyze the efficacy and safety of hematopoietic progenitor cells (HPC) collections by leukapheresis in pediatric patients with brain tumors.

Results

Between 2003 and 2014, we collected HPC from 19 children (12 boys/7 girls), median age at the diagnosis of 5 years old (<1–15 years old) and weight of 16.8 Kg (6.7–42). Diagnoses were Medulloblastoma (n = 10), Primitive Neuroectodermal Tumor (n = 5), Atypical Teratoid Rhabdoid Tumor (n = 3) and Secreting Germ Cell Tumor (n = 1). All patients performed leukapheresis by a central venous catheter, at the fifth day of mobilization with G‐CSF (median dose 11.7 µg/Kg/day), 9 of them with COBE® Spectra and 10 with Spectra Optia®. The anticoagulant used was ACD‐A, ratio of 14:1 or ACD‐A plus heparin, ratio 25:1. The tubing set was primed with a compatible, irradiated, leukodepleted and hematocrit adjusted packed red cells for all children <30 kg (n = 17). A median of 1.5 (1–3) leukapheresis per patient was performed with an average of 3 (1.5–5.4) blood volumes processed; 3 children did a second mobilization and one additional leukapheresis. The median number of CD34+ cells collected was 4.6 × 106/Kg (0.18–22.6) of patient body weight; 12 children collected for a tandem transplant. The median time between cell collection and infusion was 3 (0.6–9.1) months.

Conclusions

HPC collection in children is an efficient and well tolerated technique, performed as an outpatient procedure. With the new mobilization schemes and leukapheresis technology, we can collect a high number of HPC allowing pediatric oncologist to establish more aggressive chemotherapy protocols hoping to improve patient outcome. J. Clin. Apheresis 31:22–28, 2016. © 2015 Wiley Periodicals, Inc.
Nonsuicidal Self‐Injury and Affect Regulation: Recent Findings From Experimental and Ecological Momentary Assessment Studies and Future Directions
Authors: Hamza Chloe A. , Willoughby Teena
Published: April 2015

Context

Although research indicates that nonsuicidal self‐injury (NSSI) may be used as a form of emotion regulation, studies have largely relied on the use of retrospective self‐report data, which limits inferences about directionality of effects. Recently, researchers have started to employ lab‐based experimental (e.g., guided imagery, acute pain) and moment sampling approaches to the study of NSSI.

Methods

In the present study, we conducted a review of this recent literature, using several electronic databases (e.g., PsychINFO, ERIC, CINAHL).

Results

We identified 18 studies that met our inclusion criteria. Findings indicated that the administration of pain was associated with decreases in negative affect among both self‐injurers and noninjurers, although these declines were more pronounced for self‐injurers in some studies.

Conclusions

We discuss findings within the context of two central theories (i.e., opponent‐process theory and distraction theory) and offer several recommendations for future research in this area.
Noninvasive investigation of exocrine pancreatic function: Feasibility of cine dynamic MRCP with a spatially selective inversion‐recovery pulse
Authors: Yasokawa Kazuya , Ito Katsuyoshi , Tamada Tsutomu , Yamamoto Akira , Hayashida Minoru , Tanimoto Daigo , Higaki Atsushi , Noda Yasufumi , Kido Ayumu
Published: April 2015

Purpose

To investigate the feasibility of noncontrast‐enhanced cine dynamic magnetic resonance cholangiopancreatography (MRCP) with a spatially selective inversion‐recovery (IR) pulse for evaluating exocrine pancreatic function in comparison with the N‐benzoyl‐L‐tyrosyl‐p‐aminobenzoic acid (BT‐PABA) test as a pancreatic exocrine function test.

Materials and Methods

Twenty subjects with or without chronic pancreatitis were included. MRCP with a spatially selective IR pulse was repeated every 15 seconds for 5 minutes to acquire a total of 20 images (cine‐dynamic MRCP). The median and mean frequency of the observation (the number of times) and the moving distance (mean secretion grading scores) of pancreatic juice inflow on cine‐dynamic MRCP were compared with a BT‐PABA test.

Results

The urinary PABA excretion rate (%) had significant positive correlations with both the mean secretion grade (r = 0.66, P = 0.002) and frequency of secretory inflow (r = 0.62, P = 0.004) in cine dynamic MRCP. Both the mean frequency of observations of pancreatic secretory inflow (1.4 ± 1.6 times vs. 14.3 ± 4.2 times, P < 0.001) and the mean secretion grade (grade = 0.16 ± 0.24 vs. grade = 1.81 ± 0.81, P < 0.001) was significantly lower in the chronic pancreatitis group than in the normal subject group.

Conclusion

Cine dynamic MRCP with a spatially selective IR pulse may have potential for estimating the pancreatic exocrine function noninvasively as a substitute for the BT‐PABA test. J. Magn. Reson. Imaging 2015;42:1266–1271.
Thermal lens detection of one and two‐color laser excitation of benzene in cryogenic liquid solutions
Authors: Diez‐y‐Riega Helena , Camejo David , Manzanares Carlos E.
Published: April 2015

The thermal lens technique is applied to vibrational overtone spectroscopy of cryogenic solutions of benzene. The pump and probe thermal lens technique has been found to be very sensitive for detecting samples of low concentration in transparent liquefied gas solvents at low temperatures. The C–H fifth vibrational (Δυ = 6) overtone of benzene in liquefied ethane, krypton, and argon have been recorded at concentrations between 10 and 58 p.p.m. in a range of temperatures between 87 and 150 K. Experiments with one‐color laser excitation are sensitive enough to detect benzene at parts per million mole fraction. The dependence of the signal on the physical properties of the solvent and the excitation wavelength are shown. Finally, a thermal lens experiment with two‐color laser excitation is presented showing an increase in the magnitude of the peak absorption that will result in an increase of the limit of detection. A three‐level model to explain signal enhancement with respect to one‐color laser excitation under the same experimental conditions is presented. Copyright © 2015 John Wiley & Sons, Ltd.
Backpacking Through an Ontology of Becoming: A Never‐ending Cycle of Journeys
Authors: Tomazos Konstantinos
Published: April 2015

By adopting an ontological stance of becoming, this study traces qualitatively the journeys of contemporary backpacker tourists using the theoretical construct of the ‘Hero's Journey’ as a conceptual vehicle. This process allows for the development of a cyclical model of experience that illustrates the backpacker's experience in three stages of departure, initiation and return. This approach reveals the role that former backpackers play through the sharing of knowledge and the invaluable support they offer to novice backpackers through a network of support that is available to contemporary backpackers who choose to follow established backpacking trails. This never ending cycle of journeys becomes instrumental into the shaping of what this paper see as the common, collective consciousness of the backpacking experience and the evolution of the backpacking experience market. Copyright © 2015 John Wiley & Sons, Ltd.
Validating the Use of 137Cs Measurements to Derive the Slope Component of the Sediment Budget of a Small Rangeland Catchment in Southern Italy
Authors: Porto Paolo , Walling Desmond E. , La Spada Carmelo , Callegari Giovanni
Published: April 2015

The sediment budget is a key concept and tool for characterizing the mobilization, transfer and storage of fine sediment within a catchment. Caesium‐137 measurements can provide valuable information on gross and net erosion rates associated with sheet and rill erosion that can be used to establish the slope component of a catchment sediment budget. However, there is a need to validate the use of 137Cs measurements for this purpose, because their reliability has sometimes been questioned. The study reported focuses on a small (3·04 ha) steepland (mean slope 37%) catchment in Southern Italy. It exploits the availability of information on the medium‐term sediment output from the catchment provided by the construction of a reservoir at its outlet in 1978 and the existence of estimates of soil redistribution rates derived from 137Cs measurements made on 68 replicate soil cores collected from the slopes of a substantial proportion of the catchment in 2001, to validate the use of 137Cs measurements to construct the slope component of the catchment sediment budget. An additional 50 replicate soil cores were collected from the catchment slopes for 137Cs analysis, to complement the data already available. Nine cores collected from the area occupied by the reservoir were used to estimate the mean annual sediment input to the reservoir. In the absence of evidence that the poorly developed channel system in the catchment was either a significant sediment source or sink, it was possible to directly compare the estimate of net soil loss from the catchment slopes (7·33 Mg ha−1 y−1) with the estimate of sediment output from the catchment provided by the reservoir deposits (7·52 Mg ha−1 y−1). Taking account of the uncertainties involved, the close agreement of the two values is seen as providing a convincing validation of the use of 137Cs measurements to both estimate soil redistribution rates and as a basis for constructing the slope component of the sediment budget of a small catchment. Copyright © 2015 John Wiley & Sons, Ltd.
Dating archaeological copper using electrochemical impedance spectroscopy. Comparison with voltammetry of microparticles dating
Authors: Doménech‐Carbó A. , Capelo S. , Piquero J. , Doménech‐Carbó M. T. , Barrio J. , Fuentes A. , Al Sekhaneh W.
Published: April 2015

A methodology for dating copper/bronze archaeological objects aged under atmospheric environments using electrochemical impedance spectroscopy (EIS) is described. The method is based on the measurement of resistance associated to the growth of corrosion layers in EIS recorded upon immersion of the pieces in mineral water and applying a bias potential for the reduction of dissolved oxygen. Theoretical expressions for the time variation of such resistance following a potential rate law are presented. Equivalent expressions are derived and applied for estimating the variation of the tenorite/cuprite ratio from their specific voltammetric signals using voltammetry of microparticles data. Calibration curves were constructed from a set of well‐documented coins.
Modeling of Highly Branched Water‐Soluble Polymers with Applications to Drug Delivery Model Extensions and Validation
Authors: Kim Seung Yeon , Van Dyke Robert , Chang Kai , Taite Lakeshia J. , Schork Francis Joseph
Published: April 2015

Reversible addition fragmentation transfer (RAFT) polymerization can be used to produce highly branched polymer approximating the structure of dendrimers, but with less regularity and much less synthetic complexity. This can be accomplished by using a RAFT agent with a polymerizable double bond. Thus, the stoichiometry is fixed, with one branch point (RAFT agent double bond) per chain. Since each of these branch points will also branch, a highly regular highly branched material is formed. If this RAFT chemistry is applied to the monomer N‐isopropyl‐acrylamide (NIPAAm), the resulting water‐soluble polymer has unique applications in drug delivery, due to the hyperbranched nature of the polymer, and also to the lower critical solution temperature exhibited by poly(NIPAAm). In this paper, a previous mathematical model of the RAFT‐pNIPAAm system is extended, and validated against experimental polymerization data.
Vom Gewinn des Scheiterns
Authors: Huesmann David , Neidlinger Andreas , Reusch Nicola
Published: April 2015

Negativ‐ und Nullresultate sind wichtig auf dem Weg zu neuen Erkenntnissen. Unerwartete Ergebnisse werden jedoch häufig nicht publiziert, weil die Untersuchungen scheinbar nicht erfolgreich waren. Das will das Journal of Unsolved Questions ändern und dient deshalb seit vier Jahren als Medium für solche Publikationen.
Staub oder Diamant?
Authors: Fischer Lars
Published: April 2015

Die Chemie macht selbst vor dem Tod nicht halt — im Gegenteil, manchmal geht sie dann erst richtig los: beim Erhalten und beim Zerstören einer Leiche.
Ganz genau getankt
Authors: Bulmahn Maren
Published: April 2015

Für Wasserstoffperoxid statt Benzin entschieden sich die meisten Wettbewerber, um ihr Chemcar voranzubringen. Aber auch Ameisensäure war gefragt.
Vom Laborat zum Chloratat
Authors: Guggolz Ernst
Published: April 2015

In diesem Jahr geht es nicht nur um Stilblüten in deutschen Zeitungen und Zeitschriften und online, sondern auch um allerlei Sonderbares im täglichen Lebenskampf.
Künstliche Intelligenz aus dem Chemiereaktor
Authors: Braun Artur , Toth Rita , Lagzi Istvan
Published: April 2015

Der zeitlich‐räumliche Verlauf von chemischen Reaktionen ermöglicht analoge und parallele Simulationen von Transportprozessen. Dieses Verfahren kann schneller sein als das mit herkömmlichen digitalen, sequenziellen Computern. Ein Beispiel sind Flüssigkeiten in einem Labyrinth.
Positiver Trend bei Chemietransaktionen
Authors: Schneider Bernd , Riemann Raphael
Published: April 2015

Nach einem herausragenden Jahr sind die Märkte für Fusionen und Übernahmen in der chemischen Industrie auch in diesem Jahr auf einem guten Weg.
Unersetzlich oder nicht?
Authors: Prechtl Fritz
Published: April 2015

Immer noch glauben zu viele der für Produktsicherheit zuständigen Personen, dass der Ablauf der Reach‐Registrierfrist am 31. Mai 2018 noch Zeit zum Abwarten ließe. Die noch anstehenden Aufgaben und die möglichen Konsequenzen machen aber klar, wie notwendig die frühzeitige Vorbereitung ist.
Blei im Hirsch, Kupfer im Reh?
Authors: Stawitz Melanie , Schlösser Joachim
Published: April 2015

Jagdverbände und Handel fördern gezielt das Bio‐Image von Wildfleisch. Auch die Möglichkeit, Wildfleisch über lokale Jäger zu beziehen, kommt dem Wunsch vieler Verbraucher nach Lebensmitteln aus der Region entgegen. Doch wie stark ist Wildfleisch mit giftigen Metallen belastet? Elementanalytik mit ICP‐MS schafft Klarheit.
Cerebral white matter fractional anisotropy and tract volume as measured by MR imaging are associated with impaired cognitive and motor function in pediatric posterior fossa tumor survivors
Authors: Rueckriegel Stefan M. , Bruhn Harald , Thomale Ulrich W. , Hernáiz Driever Pablo
Published: April 2015

Background

Disease and therapy cause brain damage and subsequent functional loss in pediatric patients with posterior fossa tumors. Treatment‐related toxicity factors are resection in patients with pilocytic astrocytoma (PA) and, additionally, cranio‐spinal irradiation together with chemotherapy in patients with medulloblastoma (MB). We tested whether damage to white matter (WM) as revealed by diffusion tensor MR imaging (DTI) correlated with specific cognitive and motor impairments in survivors of pediatric posterior fossa tumors.

Procedures

Eighteen MB (mean age ± SD, 15.2 ± 4.9 y) and 14 PA (12.6 ± 5.0 y) survivors were investigated with DTI on a 3‐Tesla‐MR system. We identified fractional anisotropy (FA) of WM, the volume ratio of WM to gray matter and cerebrospinal fluid (WM/GM + CSF), and volume of specific frontocerebellar tracts. Ataxia was assessed using the International Cooperative Ataxia Rating Scale (ICARS), while the Wechsler Intelligence Scale for Children determined full‐scale intelligence quotients (FSIQ). Amsterdam Neuropsychological Tasks (ANT) was used to assess processing speed. Handwriting automation was analyzed using a digitizing graphic tablet.

Results

The WM/GM + CSF ratio correlated significantly with cognitive measures (IQ, P = 0.002; ANT baseline speed, P = 0.04; ANT shifting attention, P = 0.004). FA of skeletonized tracts correlated significantly with FSIQ (P = 0.008), ANT baseline speed (P = 0.028) and ANT shifting attention (P = 0.045). Moreover, frontocerebellar tract volumes correlated with both the FSIQ (P = 0.011) and ICARS (P = 0.007).

Conclusion

DTI provides a method for quantification of WM damage by tumor and by therapy‐associated effects in survivors of pediatric posterior fossa tumors. DTI‐derived WM integrity may be a representative marker for cognitive and motor deterioration. Pediatr Blood Cancer 2015;62:1252–1258. © 2015 Wiley Periodicals, Inc.
Direct drawing of gel fibers enabled by twist‐gel spinning process
Authors: Wyatt Tom , Gainey Teyana , Fang Xudong , Yao Donggang
Published: April 2015

A new twist‐gel spinning process for ultrahigh molecular weight polyethylene fibers is demonstrated which significantly increases the extraction rate of nonvolatile spin solvent while simultaneously reducing the consumption of extraction solvent by more than 75%. Applying twist to the gel fiber enables it to be directly hot‐drawn, allowing conventional solvent extraction to proceed significantly faster. While solvent extraction effectiveness is largely enhanced, the new process does not show reduced fiber properties. The tensile strength, Young's modulus, surface morphology, and geometry are relatively unaffected when compared to fibers produced using the conventional gel‐spinning process. The new twist‐gel spinning process is expected to improve the processing efficiency of gel‐spun high‐strength fibers, promoting broad expansion of these high performance fibers into applications that were previously prohibitive due to extremely slow production. POLYM. ENG. SCI., 55:1389–1395, 2015. © 2015 Society of Plastics Engineers
Investigation of polyacrylonitrile solution inhomogeneity by dynamic light scattering
Authors: Raghavan Vijay , Gupta Murari , Xiao Zhiwei , Gi Chae Han , Liu Tao , Kumar Satish
Published: April 2015

Dynamic light scattering (DLS) has been used to quantify nanoscale heterogeneity in the industrially significant polyacrylonitrile (PAN) polymer solution. The heterogeneity in polymer solution, traced by the ratio of amplitudes of the slow to fast mode, is observed to be related to various parameters, such as molecular weight of the polymer, the type of co‐monomer, processing time, concentration of the solution, and the choice of the solvents. It has been identified that low molecular weight PAN homopolymer have the least heterogeneity issues. Amongst the chosen co‐polymers for this study, similar degree of heterogeneity was observed at concentration slightly above the critical concentration at which the polymer chains begin to overlap. Whereas, at higher concentration, PAN‐methacrylic acid (4 wt%) copolymer showed the least heterogeneity issue. The aggregate diffusion coefficient of PAN‐methacrylic acid (4 wt%) copolymer solution in dimethylformamide (DMF) andN,N‐dimethylacetamide (DMAc) are respectively determined to be ∼1.6 × 10−12cm2/s and ∼1.6 × 10−13cm2/s, which results in an estimated aggregate size of 9 nm and 90 nm. POLYM. ENG. SCI., 55:1403–1407, 2015. © 2015 Society of Plastics Engineers
Phthalonitrile end‐capped polyarylene ether nitrile: crystals embedded in matrix through crosslinking reaction
Authors: Tong Lifen , Jia Kun , Liu Xiaobo
Published: April 2015

A novel single‐component composite based on phthalonitrile end‐capped polyarylene ether nitrile (PEN‐Ph) which undergoes a crosslinking reaction combined with crystallization behavior has been prepared successfully by hot compressing. The project focuses on studying the influence of the processing temperature and curing time on the crosslinking reaction and crystallization behavior. Differential scanning calorimetry analysis indicates that the crosslinking degree increases with an increase of processing temperature and curing time. In contrast, the crystallinity increases first and then decreases as the curing time increases, owing to the effect of the restriction of the crosslinking reaction on the crystallization behavior. Thermal polarizing microscope images provide direct evidence for crystal formation as a result of crosslinking reaction. Moreover, through comparative analysis of amorphous and crystallized PEN‐Ph sheets, the conclusion is drawn that the glass transition temperature and mechanical properties are affected by not only the degree of crosslinking but also by the crystallinity. © 2015 Society of Chemical Industry
Mechanical metamaterials with anisotropic and negative effective mass‐density tensor made from one constituent material
Authors: Bückmann T. , Kadic M. , Schittny R. , Wegener M.
Published: April 2015

If one replaces the bulk masses in a three‐dimensional (3D) mass‐and‐spring model of a solid by composite masses made of different springs connected to a heavy internal mass, one obtains a paradigm for a metamaterial with an effectively frequency‐dependent and anisotropic mass‐density tensor. Besides the different internal eigenfrequencies, components of this tensor can become negative. Today, such structures can be fabricated by using 3D printing – usually, however, only out of one constituent material and with constraints regarding the maximum ratio of unit cell size to minimum feature size. Here, we use numerical phonon band structure calculations to study what performance can be expected with current fabrication technology.
A 5.1% efficient kesterite Cu2ZnSnS4 (CZTS) thin film solar cell prepared using modified sulfurization process
Authors: Gang Myeng G. , Gurav Kishor V. , Shin Seung W. , Hong Chang W. , Min Jung H. , Suryawanshi Mahesh P. , Vanalakar Sharad A. , Lee Dong S. , Kim Jin H.
Published: April 2015

Cu2ZnSnS4 (CZTS) absorber thin films are prepared by sulfurization of sputtered Cu/Sn/Zn (CZT) stacked metallic precursor. The modified sulfurization process is adapted to prepare photovoltaic quality CZTS films. Specifically, sputtered CZT precursor films are sulfurized in sulfur powder contained graphite box using rapid thermal processing furnace at 580 °C for 10 min, in N2(95%) + H2S (5%) atmosphere. The Cu‐poor CZTS films with various Cu/(Zn+Sn) ratio are prepared by varying Cu layer deposition time. The effect of Cu/(Zn+Sn) ratio on the properties of CZTS films is investigated. The CZTS thin film solar cells with Cu/(Zn+Sn)=0.76 shows best conversion efficiency of 5.1% (Voc: 573 mV, Jsc: 18.38 mA/cm2, FF: 0.48%, and active area: 0.31 cm2). (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization and effect of calcination temperature on structural properties of spinel zinc aluminate synthesized via Co‐precipitation process
Authors: Mekprasart Wanichaya , Worasawat Suchada , Tangcharoen Thanit , Pecharapa Wisanu
Published: April 2015

Zinc aluminate (ZnAl2O4) nanopowders were synthesized by co‐precipitation method using zinc chloride and aluminum chloride as starting precursors. The calcination temperature which was a crucial preparation factor was varied and its influence on relevant physical properties of the product was investigated. Structural properties of synthesized nanoparticles were investigated by X‐ray diffraction, X‐ray absorption spectroscopy, scanning electron microscope, and Raman spectroscopy. The results suggest that that ZnAl2O4 in spinel structure with high crystallinity can be obtained after calcination beyond specific temperature affirmed by XRD results. Raman result indicates the correlated chemical bonding relating to the formation of ZnAl2O4 structure. Meanwhile, the Zn K‐edge X‐ray absorption near‐edge structure (XANES) spectra of these samples with different calcination temperature obtained from the synchrotron X‐ray absorption spectroscopy measurement show the existence of accurate oxidation state for zinc ion (Zn2+) in the spinel crystal structure. Moreover, it is revealed that the calcination temperature has significant effect on the local environment of the zinc absorbing atoms through the interesting change of white line appearance. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The validities of centrifugal sudden approximations in chemical reaction dynamics
Authors: Chu Tianshu , Liang Dongyue , Xu Jinmei , Dong Shunle
Published: April 2015

In this review article, we discuss and analyze the validities of centrifugal sudden (CS) approximations in chemical reactions, with emphasis on the recent progress in the comparison studies of close‐coupling and CS approximations in chemical dynamics both adiabatically and nonadiabatically. All these relevant studies are performed using the time‐dependent wave packet approach, focusing on several typical and benchmark chemical reactions, for example, the triatomic adiabatic ion–molecule reactions of Ne + 
, He + HeH+, O+ + H2, O+ + D2, and O+ + HD, the triatomic nonadiabatic reactions of N + NH and O + N2, and the tetraatomic and polyatomic adiabatic reactions of H2 + D2 and H + CHD3. © 2015 Wiley Periodicals, Inc.
Do‐no‐harm versus do‐good social responsibility: Attributional thinking and the liability of foreignness
Authors: Crilly Donal , Ni Na , Jiang Yuwei
Published: April 2015

Research summary: The efforts of multinational corporations to be socially responsible do not always engender positive evaluations from overseas stakeholders. Drawing on attribution theory, we argue that two heuristics guide stakeholders in evaluating firms' social performance: foreignness and the valence of firms' social responsibility. We provide evidence from a field study of secondary stakeholders and an experimental study involving 129 non‐governmental organizations. Consistent with attribution theory, the liability of foreignness is minimized when firms engage in “do‐good” social responsibility (focused on proactive engagement creating positive externalities) but is substantial when firms engage in “do‐no‐harm” social responsibility (focused on attenuating negative externalities). In online supporting information, Appendix S1, we demonstrate that these evaluations have consequences for whether stakeholders subsequently cooperate, or sow conflict, with firms.

Managerial summary: There is no guarantee that efforts to be socially responsible will improve multinational corporations' relations with overseas stakeholders, such as customers, governments, and activists. In a field study and an experiment, we unpack when foreign firms suffer from harsh stakeholder evaluations. Foreign firms especially suffer from harsh evaluations when they conduct “do‐no‐harm” CSR rather than “do‐good” CSR. Stakeholders attribute the motive for foreign firms' do‐no‐harm CSR to managerial interests and shareholder pressures, perceiving a wedge between managers and owners (who may be unmotivated to reduce the negative impacts of their business activities) and local stakeholders (who bear the social costs). A practical implication is that foreign firms gain more from highlighting do‐good rather than do‐(no)‐harm CSR initiatives. Copyright © 2015 John Wiley & Sons, Ltd.
Disruption of cardiogenesis in human embryonic stem cells exposed to trichloroethylene
Authors: Jiang Yan , Wang Dan , Zhang Guoxing , Wang Guoqing , Tong Jian , Chen Tao
Published: April 2015

Trichloroethylene (TCE) is ubiquitous in our living environment, and prenatal exposure to TCE is reported to cause congenital heart disease in humans. Although multiple studies have been performed using animal models, they have limited value in predicting effects on humans due to the unknown species‐specific toxicological effects. To test whether exposure to low doses of TCE induces developmental toxicity in humans, we investigated the effect of TCE on human embryonic stem cells (hESCs) and cardiomyocytes (derived from the hESCs). In the current study, hESCs cardiac differentiation was achieved by using differentiation medium consisting of StemPro‐34. We examined the effects of TCE on cell viability by cell growth assay and cardiac inhibition by analysis of spontaneously beating cluster. The expression levels of genes associated with cardiac differentiation and Ca2+ channel pathways were measured by immunofluorescence and qPCR. The overall data indicated the following: (1) significant cardiac inhibition, which was characterized by decreased beating clusters and beating rates, following treatment with low doses of TCE; (2) significant up‐regulation of the Nkx2.5/Hand1 gene in cardiac progenitors and down regulation of the Mhc‐7/cTnT gene in cardiac cells; and (3) significant interference with Ca2+ channel pathways in cardiomyocytes, which contributes to the adverse effect of TCE on cardiac differentiation during early embryo development. Our results confirmed the involvement of Ca2+ turnover network in TCE cardiotoxicity as reported in animal models, while the inhibition effect of TCE on the transition of cardiac progenitors to cardiomyocytes is unique to hESCs, indicating a species‐specific effect of TCE on heart development. This study provides new insight into TCE biology in humans, which may help explain the development of congenital heart defects after TCE exposure. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1372–1380, 2016.
Effect of MnOx Loading on Structural, Surface, and Catalytic Properties of CeO2‐MnOx Mixed Oxides Prepared by Sol‐Gel Method
Authors: Jampaiah Deshetti , Venkataswamy Perala , Tur Katie M. , Ippolito Samuel J. , Bhargava Suresh K. , Reddy Benjaram M.
Published: April 2015

Nanosized CeO2‐MnOx mixed oxides with different Ce/Mn ratios were prepared by a citric acid‐assisted sol‐gel method. The effect of the MnOx content on structural, redox, and surface properties of the CeO2‐MnOx was investigated by various techniques, namely, BET surface area, SEM, XRD, ICP‐OES, Raman and FT‐IR spectroscopy, H2‐TPR, and XPS. Catalytic activity was evaluated with soot‐catalyst mixture under tight contact conditions. BET surface area analysis indicated that Mn doping favors an enhancement in the surface area of pure CeO2. Raman active peaks for both pure CeO2 and CeO2‐MnOx mixed oxides were determined at ca. 460 cm–1. The observed Raman shift can also be assigned to Raman active modes of CeO2 that are shifted from the original position due to different Mn doping. Formation of Ce1–xMnxO2–δ solid solutions was further confirmed by XRD and FT‐IR analysis. H2‐TPR results demonstrate that Ce1–xMnxO2–δ solid solutions significantly improved the redox property over the pure CeO2 or MnOx. XPS analysis reveal that Ce is in the form of Ce4+ and Ce3+, and Mn existed in the form of Mn4+, Mn3+, and Mn2+ on the surface of the samples. Catalytic activity results indicate that the oxidation temperature of soot can be significantly reduced by CeO2‐MnOx mixed oxides, which render higher Ce3+ concentration and more surface oxygen vacancies compared with pure CeO2. Particularly, the Ce0.7Mn0.3O2–δ sample exhibited highest activity (a shift of T50 by ca. 122 K) compared to pure ceria.