bluuebunny/crossref_metadata_2025_split huggingface dataset:
The 3‐Acetyloxaphosphirane/1,3,2‐Dioxaphosphol‐4‐ene Rearrangement
Authors: Abdrakhmanova Liliya , Schnakenburg Gregor , Espinosa Arturo , Streubel Rainer 
Published: October 2013

AbstractAn Li/Cl phosphinidenoid complex, obtained by chlorine/lithium exchange from a [dichloro(organo)phosphane]tungsten(0) complex, reacted with aliphatic dicarbonyl derivatives to provide oxaphosphirane complexes, a 1,3,2‐dioxaphosphol‐4‐ene complex, and a P‐alkoxyphosphane complex; the latter is formally derived from the enol form of the β‐diketone. DFT calculations on the ring‐expansion rearrangement support a preferred mechanism involving a pericyclic [1,3] shift of the phosphorus fragment in an oxaphosphirane complex rather than a stepwise diradical or ionic mechanism. The latter is slightly unfavored (ΔΔE‡ = 2.2 kcal/mol) and involves heterolytic P–C bond cleavage to give a methylene oxonium phosphanide intermediate and cyclization through a low‐lying transition state featuring an unusual linear C–O–P geometry.
Estimation of the caloric value of low‐calorie cocoa butter and evaluation of its effects on biochemical and physiological parameters of rats fed high‐fat diet in vivo
Authors: Wu Wei‐Liang , Pan Lu‐Yun , Tan Zhi‐Qiang , Yuan Lu , Zhu Wen‐Liang , Li Xiao‐Ming , Liang De‐Pei , Zhou Yong , Li Jiang , Zheng Jian‐Xian 
Published: October 2013

The first aim of the present work was to assess the caloric value of low‐calorie cocoa butter (LCCB) prepared by enzymatic transesterification. A growth method on restricted diet was utilized for the assessment with cocoa butter (CB) as a caloric control. Thirty weanling Wistar male rats were divided into six groups and fed for 3 weeks. The estimated caloric value of LCCB was 4.70 kcal/g, exhibited a decrement of 31%. Furthermore, a growth experiment using pair‐feeding protocol was performed to evaluate whether high LCCB diet could have any effect on the biochemical and physiological parameters, such as TAG, total cholesterol, high‐density lipoprotein cholesterol, low‐density lipoprotein cholesterol, enzymatic activities of superoxide dismutase and catalase, Lee's index, liver index, the atherosclerosis index, and the risk of coronary heart disease. The results revealed that high LCCB dietary intake did not significantly alter the biochemical parameters except for the LDL‐c. The fatty acid compositions of plasmas and feces demonstrated that caprylic acid was completely consumed through hepatic portal vein for energy supply, while most behenic acid was excreted. These results suggest that the calorie of CB has been lowered by transesterification and the high LCCB diet do not readily induce obesity or oxidative stress.Practical applications: A method to evaluate the caloric value of fats and oils is presented. A low‐calorie cocoa butter may be useful for the chocolate industry.
Enzymatic hydrolysis of p‐nitrophenyl butyrate in CO2‐based micelle systems
Authors: Shang Wenting , Zhang Xiaogang , Yang Xiaoxi , Zhang Shuang 
Published: October 2013

AbstractBACKGROUNDIn this work, CO2‐based micelles with TMN series surfactants were used as reactive medium. Hydrolysis of p‐nitrophenyl butyrate catalyzed by porcine pancreas was used as a model reaction. The reactive behavior was used to optimize the reaction temperature, pH, pressure, enzyme concentration and the added water.RESULTS AND DISCUSSIONGenerally, the reaction parameters depended on the types of substrates and enzymes. For the hydrolysis of p‐nitrophenyl butyrate in CO2‐based micelles, the reactive yield reached a high level at temperature 303 K, system pressure 15 MPa, pH 6.8, water to surfactant ratio W0 15, and enzyme concentration 1 g mL‐1. In addition, the system reactivity was highest when TMN‐6 surfactant was used.CONCLUSIONSThe activity of lipase‐catalyzed hydrolysis in CO2‐based micelle was increased significantly compared with that obtained in cyclohexane oil micelle. The combination of enzyme with supercritical CO2 represented a promising ‘green’ reaction system for bioconversions. © 2013 Society of Chemical Industry
Differentiated Overt Learning Activities for Effective Instruction in Engineering Classrooms
Authors: Menekse Muhsin , Stump Glenda S. , Krause Stephen , Chi Michelene T. H. 
Published: October 2013

AbstractBackgroundSimilar to other domains, engineering education lacks a framework to classify active learning methods used in classrooms, which makes it difficult to evaluate when and why they are effective for learning.Purpose/HypothesisThis study evaluated the effectiveness and applicability of the Differentiated Overt Learning Activities (DOLA) framework, which classifies learning activities as interactive, constructive, or active, for engineering classes. We tested the ICAP hypothesis that student learning is more effective in interactive than constructive activities, which are more effective than active activities, which are more effective than passive activities.Design/MethodWe conducted two studies to determine how and to what degree differentiated activities affected student learning outcomes; we measured student knowledge and understanding of materials science and engineering concepts.ResultsStudy 1 showed that students scored higher on all postclass quiz questions after participating in interactive and constructive activities than after the active activities. Student scores on more difficult, inference questions suggested that interactive activities provided significantly deeper learning than constructive or active activities. Study 2 showed that student learning, in terms of gain scores, increased systematically from passive to active to constructive to interactive, as predicted by the ICAP hypothesis. All the increases, from condition to condition, were significant.ConclusionsOur analyses of classroom activities in the engineering domain showed that they fit within the taxonomy of the DOLA framework. The results of the two studies provided evidence to support the predictions of the ICAP hypothesis.
Conceptual Understanding of Electrical Circuits in Secondary Vocational Engineering Education: Combining Traditional Instruction with Inquiry Learning in a Virtual Lab
Authors: Kollöffel Bas , de Jong Ton 
Published: October 2013

AbstractBackgroundTraditionally, engineering curricula about electrical circuits use textbook instruction and hands‐on lessons, which are effective approaches for teaching terms and definitions, the procedural use of formulas, and how to build circuits. Nonetheless, students often lack conceptual understanding.Purpose (Hypothesis)The aim of this study was to discover how to facilitate the acquisition of conceptual understanding. We hypothesized that adding an instructional approach in the form of inquiry learning in a virtual lab would be more effective than relying on traditional instruction alone.Design/MethodStudents in secondary vocational engineering education were randomly assigned to one of two conditions in a quasi‐experimental study. In the traditional condition, the curriculum was supplemented with computer‐based practice. In the virtual lab condition, the traditional curriculum was supplemented with inquiry learning in a virtual lab.ResultsResults showed that students in the virtual lab condition scored significantly higher on conceptual understanding (Cohen's d = 0.65) and on procedural skills (d = 0.76). In particular, students in this condition scored higher (d = 1.19) on solving complex problems. This result occurred for both complex conceptual and procedural problems.ConclusionSince students in the virtual lab condition acquired better conceptual understanding and also developed better procedural skills than students in the traditional condition, it appears that conceptual understanding and procedural skills develop in an iterative fashion.
Diversity of rotavirus strains circulating in Northern Brazil after introduction of a rotavirus vaccine: High prevalence of G3P[6] genotype
Authors: da Silva Soares Luana , de Fátima dos Santos Guerra Sylvia , do Socorro Lima de Oliveira Alessilva , da Silva dos Santos Fabiola , de Fátima Costa de Menezes Euzeni Maria , Mascarenhas Joana d'Arc Pereira , Linhares Alexandre C. 
Published: October 2013

AbstractRotavirus A (RVA) is the most common cause of severe acute gastroenteritis in infants and young children worldwide, causing 453,000 deaths annually. In Brazil, the most frequent genotype identified was G1 during almost three decades in the pre‐vaccination period; however, after anti‐rotavirus vaccine introduction, there was a predominance of G2 genotype. The aim of this study was to determine the G and P genotypes of rotaviruses isolated from children under 5 years of age with acute gastroenteritis in the Northern region of Brazil, and discuss the emergence of G3P[6] genotype. A total of 783 stool specimens were obtained between January 2011 and March 2012. RVA antigen was detected in 33% (272/783) of samples using a commercial enzyme‐linked immunosorbent assay and type‐specificity was determined by reverse‐transcription polymerase chain reaction. The most common binary combination was G2P[4], representing 41% of cases, followed by G3P[6] (15%), G1P[8] (8%), G3P[8] (4%), G9P[8] (3%), and G12P[6] (2%). G3P[6] strains were analyzed further and phylogenetic analysis of VP7 gene showed that G3 strains clustered into lineage I and showed a high degree of amino acid identity with vaccine strain RV3 (95.1–95.6%). For VP4 sequences, G3P[6] clustered into lineage Ia. It was demonstrated by the first time the emergence of unusual genotype G3P[6] in the Amazon region of Brazil. This genotype shares neither VP7 nor VP4 specificity with the used vaccine and may represent a challenge to vaccination strategies. A continuous monitoring of circulating strains is therefore needed during the post‐vaccine era in Brazil. J. Med. Virol. 86:1065–1072, 2014. © 2013 Wiley Periodicals, Inc.
Emergence of two novel norovirus genotype II.4 variants associated with viral gastroenteritis in China
Authors: Fu Jian‐guang , Ai Jing , Qi Xian , Zhang Jun , Tang Fen‐yang , Zhu Ye‐fei 
Published: October 2013

AbstractNoroviruses (NoVs) are the principal cause of epidemic viral gastroenteritis worldwide, including industrialized and developing countries. Eight hundred and fifty sporadic specimens from hospitalized children with acute gastroenteritis and 131 specimens from seven gastroenteritis outbreaks were collected during 2011–2012 in Jiangsu, China. All specimens were tested for the presence of norovirus (NoV) by real time RT‐PCR, and in these, 225/850 of sporadic specimens and 76/131 of outbreak specimens were positive. By sequencing, two novel variants termed JS2011/CHN variant and JS2012/CHN variant were found. By complete genome sequencing and phylogenetic analysis confirmed that both JS2011/CHN variant and JS2012/CHN variant shared more than 98% identity with GII.4 New Orleans/2009/USA strain and GII.4 Sydney/2012/AUS. Both of them had mutations in some key sites in nucleotide sequence and amino acid sequence of ORF1‐ORF3. Whether two novel variants will cause epidemic of NoV outbreaks in China deserves further attention. A national surveillance network may be needed to identify trends in molecular evolution of NoVs for prevention of future epidemics. J. Med. Virol. 86:1226–1234, 2014. © 2013 Wiley Periodicals, Inc.
Transcranial application of near‐infrared low‐level laser can modulate cortical excitability
Authors: Konstantinović Ljubica M. , Jelić Milan B. , Jeremić Aleksandra , Stevanović Vuk B. , Milanović Sladjan D. , Filipović Saša R. 
Published: October 2013

AbstractBackground and ObjectiveNear‐infrared low‐level laser (NIR‐LLL) irradiation penetrates scalp and skull and can reach superficial layers of the cerebral cortex. It was shown to improve the outcome of acute stroke in both animal and human studies. In this study we evaluated whether transcranial laser stimulation (TLS) with NIR‐LLL can modulate the excitability of the motor cortex (M1) as measured by transcranial magnetic stimulation (TMS).MethodsTLS was applied for 5 minutes over the representation of the right first dorsal interosseal muscle (FDI) in left primary motor cortex (M1), in 14 healthy subjects. Motor evoked potentials (MEPs) from the FDI, elicited by single‐pulse TMS, were measured at baseline and up to 30 minutes after the TLS.ResultsThe average MEP size was significantly reduced during the first 20 minutes following the TLS. The pattern was present in 10 (71.5%) of the participants. The MEP size reduction correlated negatively with the motor threshold at rest.ConclusionsTLS with NIR‐LLL induced transitory reduction of the excitability of the stimulated cortex. These findings give further insights into the mechanisms of TLS effects in the human cerebral cortex, paving the way for potential applications of TLS in treatment of stroke and in other clinical settings. Lasers Surg. Med. 45:648–653, 2013. © 2013 Wiley Periodicals, Inc.
Near‐Infrared Photovoltaic Performance of Conjugated Polymers Containing Thienoisoindigo Acceptor Units
Authors: Karakawa Makoto , Aso Yoshio 
Published: October 2013

Donor–acceptor‐type conjugated copolymers containing a thienoisoindigo unit are synthesized and characterized. In combination with benzodithiophene donor units, this strong acceptor moiety can be used to extend the light absorption of their conjugated copolymers to longer wavelengths. The absorption spectra of the copolymers show features that extended up to 1200 nm in the near infrared (NIR). The resulting optical energy gaps are very narrow, ranging from 1.20 to 1.29 eV. The copolymers are used as the donor material with PC61BM acceptor in the active layer of bulk‐heterojunction organic photovoltaic cells, and the devices exhibit photocurrent at NIR wavelengths with a power‐conversion efficiency of 0.52% under air mass (AM) 1.5 illumination.
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Tailoring the LCST of PNIPAAM‐b‐PLA‐b‐PNIPAAM Triblock Copolymers via Stereocomplexation
Authors: Zhang Xing , Tan Beng H. , He Chaobin 
Published: October 2013

Poly(N‐isopropylacrylamide)‐block‐poly(l‐lactic acid)‐block‐poly(N‐isopropylacrylamide) (PNIPAAM‐b‐PLLA‐b‐PNIPAAM) and PNIPAAM‐b‐PDLA‐b‐PNIPAAM triblock copolymers with varying polylactic acid (PLA) lengths are synthesized using a combination of ring‐opening polymerization and atom‐transfer radical polymerization. Results of 1H NMR and gel permeation chromatography analyses show that the copolymers have a well‐defined triblock structure and the PLA segment lengths can be readily controlled with monomer feed ratio. Stereocomplexation between the enantiomeric PLA segments is confirmed with differential scanning calorimetry and wide‐angle X‐ray scattering. Dynamic light scattering experiments show that (1) the LCST of PNIPAAM in water could be tailored from 32 °C up to 38.5 °C by increasing the length of PLA segments and mixing copolymers of similar molecular weight with enantiomeric PLA segments to induce stereocomplexation, and (2) the LCST of each mixed copolymer system could be tailored within a 2–3 °C range of body temperature by manipulating the ratio of the enantiomeric copolymers in solution.
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Granite rock fragmentation at percussive drilling – experimental and numerical investigation
Authors: Saadati M. , Forquin P. , Weddfelt K. , Larsson P.L. , Hild F. 
Published: October 2013

SUMMARYThe aim of this study is to numerically model the fracture system at percussive drilling. Because of the complex behavior of rock materials, a continuum approach is employed relying upon a plasticity model with yield surface locus as a quadratic function of the mean pressure in the principal stress space coupled with an anisotropic damage model. In particular, Bohus granite rock is investigated, and the material parameters are defined based on previous experiments. This includes different tests such as direct tension and compression, three‐point bending, and quasi‐oedometric tests to investigate the material behavior at both tension and confined compression stress states. The equation of motion is discretized using a finite element approach, and the explicit time integration method is employed. Edge‐on impact tests are performed, and the results are used to validate the numerical model. The percussive drilling problem is then modeled in 3D, and the bit‐rock interaction is considered using contact mechanics. The fracture mechanism in the rock and the bit penetration‐ resisting force response are realistically captured by the numerical model. Copyright © 2013 John Wiley & Sons, Ltd.
Efficacy of Glucarpidase (Carboxypeptidase G2) in Patients with Acute Kidney Injury After High‐Dose Methotrexate Therapy
Authors: Widemann Brigitte C. , Schwartz Stefan , Jayaprakash Nalini , Christensen Robbin , Pui Ching‐Hon , Chauhan Nikhil , Daugherty Claire , King Thomas R. , Rush Janet E. , Howard Scott C. 
Published: October 2013

Study ObjectiveBecause the incidence rate of renal impairment is 2–10% for patients treated with high‐dose methotrexate and renal impairment develops in 0–12.4% of patients treated for osteosarcoma, we sought to evaluate the efficacy of glucarpidase, a recently approved drug that rapidly hydrolyzes methotrexate to inactive metabolites, which allows for nonrenal clearance in patients with delayed renal methotrexate elimination.DesignPooled analysis of efficacy data from four multicenter single‐arm compassionate‐use clinical trials using protocols from 1993 to 2007.PatientsOf 476 patients with renal toxicity and delayed methotrexate elimination who were treated with intravenous glucarpidase for rescue after high‐dose methotrexate, 169 patients had at least one preglucarpidase (baseline) plasma methotrexate concentration greater than 1 μmol/L and one postglucarpidase methotrexate concentration measurement by high‐performance liquid chromatography and were included in the efficacy analysis; renal recovery was assessed in 436 patients who had at least one recorded preglucarpidase and postglucarpidase serum creatinine concentration measurement.Measurements and Main ResultsEfficacy was defined as rapid and sustained clinically important reduction (RSCIR) in plasma methotrexate concentration, with a concentration of 1 μmol/L or lower at all postglucarpidase determinations. Median age of efficacy‐evaluable patients was 20 years (range 5 weeks–84 years). Osteosarcoma (36%), non‐Hodgkin lymphoma (27%), and acute lymphoblastic leukemia (20%) were the most frequent underlying diagnoses. Median preglucarpidase serum methotrexate was 11.7 μmol/L. At the first (median 15 minutes) through the last (median 40 hours) postglucarpidase measurement, plasma methotrexate concentrations demonstrated consistent 99% median reduction. RSCIR was achieved by 83 (59%) of 140 patients. A total of 64% of patients with renal impairment greater than or equal to Common Terminology Criteria for Adverse Events grade 2 recovered to grade 0 or 1 at a median of 12.5 days after glucarpidase administration.ConclusionGlucarpidase caused a clinically important 99% or greater sustained reduction of serum methotrexate levels and provided noninvasive rescue from methotrexate toxicity in renally impaired patients.
Dampening variations in wind power generation—the effect of optimizing geographic location of generating sites
Authors: Reichenberg Lina , Johnsson Filip , Odenberger Mikael 
Published: October 2013

ABSTRACTThis paper presents a method to dampen the variations in the output of aggregated wind power through geographic allocation of wind power generation sites. The method, which is based on the sequential optimization of site localization, is applied to the Nordic countries and Germany, using meteorologic wind speed data as the input. The results show that the variability in aggregated wind power output mitigates by applying sequential optimization. For the data used in this work, the coefficient of variation (standard deviation/mean) was 0.54 for the optimized aggregation of sites, as compared with 0.91 for the present day installation. An optimal allocation of wind power generation site reduces the need for dispatch and other measures to deal with the intermittent nature of wind power. Copyright © 2013 John Wiley & Sons, Ltd.
Cost‐effective shaft torque observer for condition monitoring of wind turbines
Authors: Perišić Nevena , Kirkegaard Poul Henning , Pedersen Bo Juul 
Published: October 2013

AbstractImprovement of condition monitoring (CM) systems for wind turbines (WTs) and reduction of the cost of wind energy are possible if knowledge about the condition of different WT components is available. CM based on the WT drive train shaft torque signal can give a better understanding of the gearbox failure mechanisms as well as provide a method for detecting mass imbalance and aerodynamic asymmetry. The major obstacle preventing the industrial application of CM based on the shaft torque signal is the costly measurement equipment which is impractical for long‐term use on operating WTs. This paper suggests a novel approach for low‐cost, indirect monitoring of the shaft torque from standard WT measurements. The shaft torque is estimated recursively from measurements of generator torque, high speed shaft and low speed shaft angular speeds using the well‐known Kalman filter theory. The performance of the augmented Kalman filter with fading memory (AKFF) is compared with the augmented Kalman filter (AKF) using simulated data of the WT for different load conditions, measurement noise levels and WT fault scenarios. A multiple‐model algorithm, based on a set of different Kalman filters, is designed for practical implementation of the shaft torque estimator. Its performance is validated for a scenario where there are frequent changes of operating points. The proposed cost‐effective shaft torque estimator overcomes all major problems, which prevent the industrial application of CM systems based on shaft torque measurements. Future work will be focused on validating the method using experimental data and developing suitable signal processing algorithms for fault detection. Copyright © 2013 John Wiley & Sons, Ltd.
Evolutionary computation for feature selection in classification problems
Authors: de la Iglesia Beatriz 
Published: October 2013

Feature subset selection (FSS) has received a great deal of attention in statistics, machine learning, and data mining. Real world data analyzed by data mining algorithms can involve a large number of redundant or irrelevant features or simply too many features for a learning algorithm to handle them efficiently. Feature selection is becoming essential as databases grow in size and complexity. The selection process is expected to bring benefits in terms of better performing models, computational efficiency, and simpler more understandable models. Evolutionary computation (EC) encompasses a number of naturally inspired techniques such as genetic algorithms, genetic programming, ant colony optimization, or particle swarm optimization algorithms. Such techniques are well suited to feature selection because the representation of a feature subset is straightforward and the evaluation can also be easily accomplished through the use of wrapper or filter algorithms. Furthermore, the capability of such heuristic algorithms to efficiently search large search spaces is of great advantage to the feature selection problem. Here, we review the use of different EC paradigms for feature selection in classification problems. We discuss details of each implementation including representation, evaluation, and validation. The review enables us to uncover the best EC algorithms for FSS and to point at future research directions. WIREs Data Mining Knowl Discov 2013, 3:381–407. doi: 10.1002/widm.1106This article is categorized under:

Technologies > Classification
Technologies > Computational Intelligence
Technologies > Data Preprocessing