bluuebunny/crossref_metadata_2025_split huggingface dataset:
Student conceptions about the DNA structure within a hierarchical organizational level: Improvement by experiment‐ and computer‐based outreach learning
Authors: Langheinrich Jessica , Bogner Franz X. 
Published: October 2015

AbstractAs non‐scientific conceptions interfere with learning processes, teachers need both, to know about them and to address them in their classrooms. For our study, based on 182 eleventh graders, we analyzed the level of conceptual understanding by implementing the “draw and write” technique during a computer‐supported gene technology module. To give participants the hierarchical organizational level which they have to draw, was a specific feature of our study. We introduced two objective category systems for analyzing drawings and inscriptions. Our results indicated a long‐ as well as a short‐term increase in the level of conceptual understanding and in the number of drawn elements and their grades concerning the DNA structure. Consequently, we regard the “draw and write” technique as a tool for a teacher to get to know students' alternative conceptions. Furthermore, our study points the modification potential of hands‐on and computer‐supported learning modules. © 2015 by The International Union of Biochemistry and Molecular Biology, 43:393–402, 2015.
Prestenting for prevention of melody valve stent fractures: A systematic review and meta‐analysis
Authors: Cardoso Rhanderson , Ansari Mohammad , Garcia Daniel , Sandhu Satinder , Brinster Derek , Piazza Nicolo 
Published: October 2015

IntroductionThe role of right ventricular outflow tract (RVOT) prestenting in the prevention of Melody valve stent fractures (SFs) is not well defined. We aimed to perform a systematic review and meta‐analysis comparing the incidence of SF in Melody valve transcatheter pulmonary implants with and without prestenting.MethodsPubMed, EMBASE, and Cochrane Central were searched for studies that reported the incidence of SF in Melody valve transcatheter pulmonary implants stratified by the presence or absence of RVOT prestenting. Subgroup analyses were performed for (1) SF associated with a loss of stent integrity and (2) SF requiring reintervention.ResultsFive studies and 360 patients were included, of whom 207 (57.5%) received prestenting. Follow‐up ranged from 15 to 30 months. SF were significantly reduced in the prestenting group (16.7%) when compared to no prestenting (33.5%) (odds‐ratio [OR] 0.39; 95%CI 0.22–0.69). Patients who received prestenting also had a lower incidence of (1) SF associated with loss of stent integrity (OR 0.16; 95%CI 0.05–0.48) and (2) SF requiring reintervention (OR 0.15; 95%CI 0.02–0.91).ConclusionOur findings suggest that stenting of the RVOT prior to Melody valve implantation is associated with a reduction in the incidence of SF and fracture‐related reinterventions. © 2015 Wiley Periodicals, Inc.
Embolic protection device use and its association with procedural safety and long‐term outcomes following saphenous vein graft intervention: An analysis from the British Columbia Cardiac registry
Authors: Iqbal M. Bilal , Nadra Imad J. , Ding Lillian , Fung Anthony , Aymong Eve , Chan Albert W. , Hodge Steven , Della Siega Anthony , Robinson Simon D. ,   on behalf of the British Columbia Cardiac Registry Investigators
Published: October 2015

BackgroundEmbolic protection devices (EPDs) have been designed and introduced to reduce distal embolization and peri‐procedural myocardial infarction during saphenous vein graft (SVG) intervention. Current guidelines give a class I recommendation to EPD use during SVG intervention when technically feasible. However, the routine use of these devices has recently been debated.MethodsWe analyzed 1,359 patients undergoing isolated SVG intervention between 2008 and 2013 in the British Columbia Cardiac Registry. We analyzed (a) post‐procedural TIMI flow; and (b) target vessel revascularization (TVR) and mortality at 1 and 2 years.ResultsEPD use was an independent predictor of post‐procedural TIMI 2/3 flow (OR = 2.38, 95% CI: 1.51–3.74, P < 0.001). At 1 year, EPD use was an independent predictor for lower TVR (HR = 0.35, 95% CI: 0.14–0.85, P = 0.021) and a trend towards lower mortality (HR = 0.45, 95% CI: 0.18–1.10, P = 0.082). These associations were lost at 2 years where EPD use was not predictive of mortality (HR = 0.62, 95% CI: 0.33–1.17, P = 0.144) or TVR (HR = 0.70, 95% CI: 0.41–1.17, P = 0.176). These findings were confirmed in propensity‐matched and inverse probability treatment weighted analyses.ConclusionsIn this analysis of patients undergoing SVG intervention, EPD use was a strong predictor for improved post‐procedural TIMI flow. Whilst EPD use was associated with lower TVR and a trend for lower mortality at 1 year, these associations were lost at 2 years. These findings would appear to support the use of EPD for SVG intervention. © 2015 Wiley Periodicals, Inc.
Arylation of Amines in Alkane Solvents by using Well‐Defined Palladium–N‐Heterocyclic Carbene Complexes
Authors: Marelli Enrico , Chartoire Anthony , Le Duc Gaetan , Nolan Steven P. 
Published: October 2015

AbstractThe use of the ITent‐based series of Pd‐N‐heterocyclic carbenes precatalysts (Tent= Tentacular) enables the Buchwald–Hartwig amine arylation reaction in apolar alkane solvents. The use of such solvents is rare because of their poor solvation properties. Nonetheless, they could be of interest for industrial applications, as they can be disposed of in an energetically favorable manner and may potentially simplify product isolation. The excellent solubility of the precatalysts permitted the desired products to be obtained in yields ranging from 75 to 96 %, even with deactivated and functionalized coupling partners.
Pd‐Ag/α‐Al2O3 Catalyst Deactivation in Acetylene Selective Hydrogenation Process
Authors: Ravanchi Maryam Takht , Sahebdelfar Saeed , Fard Maryam Rahimi , Fadaeerayeni Siavash , Bigdeli Peyman 
Published: October 2015

AbstractThe selective hydrogenation of acetylene to ethylene over Pd‐Ag/α‐Al2O3 catalysts prepared by different impregnation/reduction methods was studied. The best catalytic performance was achieved with the sample prepared by sequential impregnation. A kinetic model based on first order in acetylene and 0.5th order in hydrogen for the main reaction and second‐order independent decay law for catalyst deactivation was used to fit the conversion time data and to obtain quantitative assessment of catalyst performances. Fair fits were observed from which the reaction and deactivation rate constants were evaluated. Coke deposition amounts showed a good correlation with catalyst deactivation rate constants, indicating that coke formation should be the main cause of catalyst deactivation.
Revamping an Existing Aromatics Complex with Simulated Moving‐Bed Reactor for p‐Xylene Production
Authors: Gonçalves Jonathan C. , Rodrigues Alírio E. 
Published: October 2015

AbstractA simulated moving‐bed reactor (SMBR) for the production of p‐xylene is studied as part of a proposal to modify an existing aromatics complex in order to increase the production of benzene and p‐xylene. The proposed complex includes a single‐stage crystallization unit to further purify high p‐xylene streams from a selective toluene disproportionation and said SMBR units. Mass balances for two cases are estimated, namely, the current flow of reformate fed to the complex and a twofold flow. Results show significant increases of benzene and p‐xylene for both cases compared to the current production of the complex.
Diastereomer Interconversion via Enolization: A Case Study
Authors: Renzetti Andrea , Di Crescenzo Antonello , Nie Feilin , Bond Andrew D. , Gérard Stéphane , Sapi Janos , Fontana Antonella , Villani Claudio 
Published: October 2015

AbstractThe three‐component reaction of indole, isobutyraldehyde, and methyl acetoacetate affords methyl 2‐(acetyl)‐3‐(1H‐indol‐3‐yl)‐4‐methylpentanoate as a single diastereomer. To investigate the origin of the observed diastereoselectivity, the thermodynamics and kinetics of interconversion of diastereomers 1 and 2 in solution were studied by a combination of 1H nuclear magnetic resonance (NMR) spectroscopy, high‐performance liquid chromatography (HPLC), mass spectrometry, and deuteration experiments. The results indicate that interconversion is both acid‐ and base‐catalyzed, and that the alpha carbon is the only stereolabile center in the molecule. The evidence points to an enolization mechanism for the interconversion process. The selective precipitation of 1 in the presence of the equilibrium 1⇆2 eventually results in the exclusive formation of 1 (crystallization‐induced asymmetric transformation). Chirality 27:779–783, 2015. © 2015 Wiley Periodicals, Inc.
High‐performance Polymer Membranes with Multi‐functional Amphiphilic Micelles for CO2 Capture
Authors: Kim Sang Jin , Jeon Harim , Kim Dong Jun , Kim Jong Hak 
Published: October 2015

AbstractHerein, we report a high performance polymer membrane with simultaneously large improvements in the CO2 permeability and CO2/N2 selectivity. These improvements are obtained by incorporation of a multi‐functional amphiphilic comb copolymer micelle, that is, poly(dimethylsiloxane)‐g‐poly(oxyethylene methacrylate) (PDMS‐g‐POEM), into a poly(amide‐b‐ethylene oxide) (Pebax) matrix. Both CO2 and N2 permeabilities continuously increased with PDMS‐g‐POEM content, whereas the CO2/N2 selectivity increased up to 40 wt % of PDMS‐g‐POEM, which enabled the maximum performance to approach the upper bound limit (2008). The membranes with PDMS‐g‐POEM exhibited greater CO2 permeability and CO2/N2 selectivity than those with a zeolitic imidazolate framework (ZIF‐8), a well‐known expensive inorganic filler, indicating the effectiveness of PDMS‐g‐POEM micelles for CO2 capture.
Double resonant tank LLC‐DCX based two‐stage power supply for magnetic levitation control system applications
Authors: Ma Hongbo , Liu Wenjun , Yang Jie , Qiu Zhongcai 
Published: October 2015

SummaryMagnetic levitation train power supply systems, or Maglev, are most commonly powered by 330‐V high‐voltage direct current power systems. The power supply for maglev control system is used to provide a stable voltage to the suspension control circuit, which is the key part of Maglev trains. The suspension control power supply is typically a DC–DC converter with a high voltage input and multiple low voltage outputs. The traditional solutions typically lead to the following issues, such as uncontrolled duty ratio, poor cross‐regulation capability, and low reliability. In order to solve these problems, a novel two‐stage solution employing a double resonant tank LLC DC transformer (LLC‐DCX) is proposed and developed in this paper. The proposed solution not only increases the overall conversion efficiency significantly because of the achieved soft‐switching over the entire operation range, but also realizes the low input current ripple and high reliability owing to a uniform thermal distribution. A 210‐W, 220–380‐V input laboratory prototype with four outputs is fabricated and tested, and the experimental results are presented in this paper. The declared features of the proposed solution are well demonstrated by the experimental results. Copyright © 2015 John Wiley & Sons, Ltd.
Ester‐Substituted Electron‐Poor Alkenes for Cycloaddition–Retroelectrocyclization (CA–RE) and Related Reactions
Authors: Reekie Tristan A. , Donckele Etienne J. , Ruhlmann Laurent , Boudon Corinne , Trapp Nils , Diederich François 
Published: October 2015

AbstractWe report the reactions of electron‐deficient alkenes, tetrasubstituted by carboxylic ester and cyano groups, with electron‐rich (dimethylamino)phenyl‐substituted alkynes. Mono‐ or diester‐substituted alkenes exclusively undergo the [2+2] cycloaddition–retroelectrocyclization (CA–RE) reaction, well established for multicyanated ethenes, whereas tri‐ and tetraester‐substituted alkenes also undergo a [4+2] hetero‐Diels–Alder (HDA) reaction with a third product being formed, presumably by a [3+2] cycloaddition reaction followed by rearrangement. Electrochemical studies revealed cathodic shifts of the first reduction potential of the buta‐1,3‐dienes obtained from the CA–RE reaction as cyano groups are substituted for ester moieties. Post‐CA–RE functionalization of the ester‐substituted buta‐1,3‐dienes by transesterification, diazonium chemistry, and cross‐coupling is described. The formation of a pharmacologically interesting pyrazolopyran illustrates the synthetic utility of ester‐substituted CA–RE products.
Pectenotoxin's ABCDE Ring System: A Complex Target to Test the Potential of Singlet Oxygen Super Cascades as Tools for Synthesis
Authors: Kouridaki Antonia , Sofiadis Manolis , Montagnon Tamsyn , Vassilikogiannakis Georgios 
Published: October 2015

AbstractA difuran substrate was synthesized that then participated in a singlet oxygen mediated super cascade reaction sequence to give the ABCDE ring skeleton of certain pectenotoxins. During this super cascade, two separate reaction sequences occurred in parallel to create both the [6,6]‐spiroketal and the 2,8‐dioxabicyclo[3.2.1]octane motifs in one synthetic operation.
Revealing the natural complexity of topographic change processes through repeat surveys and decision‐tree classification
Authors: Wyrick Joshua R. , Pasternack Gregory B. 
Published: October 2015

AbstractTopographic change processes (TCPs) are the mechanisms by which a landscape is interpreted to be experiencing landform deformation, and are defined by the specific actions occurring within a contiguous, localized region that cause sediment to be either deposited or eroded. Past topographic change studies have mostly been focused at the site scale. The goal of this study was to identify and delineate spatially explicit TCP types across the valley width in a 34‐km long cobble‐gravel river at the scale of one‐tenth of the bankfull channel width over a period of seven to nine years. To accomplish this, a new procedure was developed that analyzes spatial patterns of topographic change evident from differencing two raster digital elevation models and accounting for sources of uncertainty, then identifying and classifying those changes using a decision tree framework that invokes the locations of those changes as they relate to the locations of specific geographic characteristics. Once mapped, TCP polygons were analyzed for areal patterns and volumetric rates of change. Results showed that 19 unique TCP types occurred and that they have organized but complex spatial patterns. Within this study segment, overbank storage processes occurred over the most area and displaced the most net volume of sediment, while cohesive bank retreat created the largest net change in topographic elevations. Analyses of the TCPs reveal that the regulated lower Yuba River (LYR) is not experiencing the expected combination of channel incision and floodplain deposition commonly reported below dams. Instead, the LYR is a dynamic valley that is still adjusting valley‐wide to the upstream dam with a diverse suite of processes that cause the channel and floodplains to scour and fill in concert. Copyright © 2015 John Wiley & Sons, Ltd.
The role of cognitive reserve on terminal decline: a cross‐cohort analysis from two European studies: OCTO‐Twin, Sweden, and Newcastle 85+, UK
Authors: Cadar Dorina , Stephan Blossom C. M. , Jagger Carol , Johansson Boo , Hofer Scott M. , Piccinin Andrea M. , Muniz‐Terrera Graciela 
Published: October 2015

ObjectiveCognitive performance shows a marked deterioration in close proximity to death, as postulated by the terminal decline hypothesis. The effect of education on the rate of terminal decline in the oldest people (i.e. persons 85+ years) has been controversial and not entirely understood. In the current study, we investigated the rate of decline prior to death with a special focus on the role of education and socioeconomic position, in two European longitudinal studies of ageing: the Origins of Variance in the Old‐Old: Octogenarian Twins (OCTO‐Twin) and the Newcastle 85+ study.MethodsA process‐based approach was used in which individuals' cognitive scores were aligned according to distance to death. In a coordinated analysis, multilevel models were employed to examine associations between different markers of cognitive reserve (education and socioeconomic position) and terminal decline using the mini‐mental state examination (MMSE), controlling for age at baseline, sex, dementia incidence and time to death from the study entry to the time of death within each cohort.ResultsThe current findings suggest that education was positively associated with higher MMSE scores prior to death in the OCTO‐Twin, but not in the Newcastle 85+ study, independent of socioeconomic position and other factors such as baseline age, sex and time to death from the study entry. However, education was not associated with the rate of terminal decline in both of these studies.ConclusionsOur results offer only partial support to the cognitive reserve hypothesis and cognitive performance prior to death. © 2015 The Authors International Journal of Geriatric Psychiatry Published by John Wiley & Sons Ltd.
Pulmonary toxicity of indium‐tin oxide production facility particles in rats
Authors: Badding Melissa A. , Fix Natalie R. , Orandle Marlene S. , Barger Mark W. , Dunnick Katherine M. , Cummings Kristin J. , Leonard Stephen S. 
Published: October 2015

AbstractIndium‐tin oxide (ITO) is used to make transparent conductive coatings for touch‐screen and liquid crystal display electronics. Occupational exposures to potentially toxic particles generated during ITO production have increased in recent years as the demand for consumer electronics continues to rise. Previous studies have demonstrated cytotoxicity in vitro and animal models have shown pulmonary inflammation and injury in response to various indium‐containing particles. In humans, pulmonary alveolar proteinosis (PAP) and fibrotic interstitial lung disease have been observed in ITO facility workers. However, which indium materials or specific processes in the workplace may be the most toxic to workers is unknown. Here we examined the pulmonary toxicity of three different particle samples that represent real‐life worker exposures, as they were collected at various production stages throughout an ITO facility. Indium oxide (In2O3), sintered ITO (SITO) and ventilation dust (VD) particles each caused pulmonary inflammation and damage in rats over a time course (1, 7 and 90 days post‐intratracheal instillation), but SITO and VD appeared to induce greater toxicity in rat lungs than In2O3 at a dose of 1 mg per rat. Downstream pathological changes such as PAP and fibrosis were observed in response to all three particles 90 days after treatment, with a trend towards greatest severity in animals exposed to VD when comparing animals that received the same dose. These findings may inform workplace exposure reduction efforts and provide a better understanding of the pathogenesis of an emerging occupational health issue. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
Giant gain enhancement in surface‐confined resonant Stimulated Brillouin Scattering
Authors: Dostart Nathan , Kim Seunghwi , Bahl Gaurav 
Published: October 2015

AbstractThe notion that Stimulated Brillouin Scattering (SBS) is primarily defined by bulk material properties has been overturned by recent work on nanoscale waveguides. It is now understood that boundary forces of radiation pressure and electrostriction appearing in such highly confined waveguides can make a significant contribution to the Brillouin gain. Here, this concept is extended to show that gain enhancement does not require nanoscale or subwavelength features, but generally appears where optical and acoustic fields are simultaneously confined near a free surface or material interface. This situation routinely occurs in whispering gallery resonators (WGRs), making gain enhancements much more accessible than previously thought. To illustrate this concept, the first full‐vectorial analytic model for SBS in WGRs is developed, including optical boundary forces, and the SBS gain in common silica WGR geometries is computationally evaluated. These results predict that gains 104 times greater than the predictions of scalar theory may appear in WGRs even in the 100 μm size range. Further, trapezoidal cross‐section microdisks can exhibit very large SBS gains approaching 102 m−1W−1. With resonant amplification included, extreme gains on the order of 1012 m−1W−1 may be realized, which is 108 times greater than the highest predicted gains in linear waveguide systems.
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Autonomously Sensing Hydrogels for the Rapid and Selective Detection of Pathogenic Bacteria
Authors: Ebrahimi Mir‐Morteza Sadat , Laabei Maisem , Jenkins A. Tobias A. , Schönherr Holger 
Published: October 2015

The development of a versatile approach for the rapid and sensitive detection of relevant pathogenic bacteria and autonomous signaling of the detection events in reporter hydrogel film coatings is reported. Exploiting chitosan hydrogel films equipped with chromogenic or fluorogenic reporter moieties, the presence of the Gram‐negative bacterium Pseudomonas aeruginosa and the Gram‐positive bacterium Staphylococcus aureus is sensed within 1 h by detecting the characteristic enzymes α‐glucosidase and elastase with limits of detection (LOD) <45 × 10−9m and <20 × 10−9m, respectively, for this observation time. The values for the LOD are two to three orders of magnitude smaller than the concentrations of the enzymes detected in the corresponding bacterial supernatants. The results show that the covalently conjugated reporter moieties are exclusively and efficiently reacted by the associated enzyme, allowing in principle for discrimination among different types of bacteria. Since high enzyme concentrations are a result of proliferating bacteria, e.g., in wounds or food, and since the selectivity of the reporting function is easily adapted to bacteria of choice, these reporter hydrogels comprise an interesting platform for the rapid detection of bacteria.
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Rapid simulation of multiple radially growing hydraulic fractures using an energy‐based approach
Authors: Cheng Cheng , Bunger Andrew P. 
Published: October 2015

SummaryThe goal of hydraulic fracturing stimulation of horizontal wells is typically to generate uniform, simultaneously growing hydraulic fractures from 3 to 6 initiation/entry sites that are spaced within a certain interval of the wellbore comprising a so‐called stage. Because of the stress interaction among growing hydraulic fractures, however, it is hard to attain simultaneous growth of all hydraulic fractures. While models have been proven useful for devising mitigation strategies of these so‐called stress‐shadow effects, the required simulations are so computationally expensive that optimization is possible only in the simplest cases. Here, we present an approximate (energy‐based) model capable of running an entire simulation in 1–2s, which is about one million times faster than the benchmark model. The approach is built on asymptotic solutions to approximate growth of radial hydraulic fractures, a far field approximation for the stress shadow interactions among growing hydraulic fractures, and coupling the effect of the stress shadow to fracture growth via a global energy balance equation. We show very close agreement in predictions of the lengths of each fracture in the array between the approximate model and the benchmark model, thus verifying that the new approximate model is useful for optimization of hydraulic fracture design. Copyright © 2015 John Wiley & Sons, Ltd.