bluuebunny/crossref_metadata_2025 huggingface dataset:
FROM BIOLOGY TO EDUCATION: SCORING AND CLUSTERING MULTILINGUAL TEXT SEQUENCES AND OTHER SEQUENTIAL TASKS
Authors: Sukkarieh Jana Z. , von Davier Matthias , Yamamoto Kentaro
Published: August 2014

This document describes a solution to a problem in the automatic content scoring of the multilingual character‐by‐character highlighting item type. This solution is language independent and represents a significant enhancement. This solution not only facilitates automatic scoring but plays an important role in clustering students' responses; consequently, it has a nontrivial impact on the refinement of the items and/or their scoring guidelines. Furthermore, though designed for a specific problem, the proposed solution is general enough for any educational task that can be transformed into a sequential one. To name a few: It can be used for a set of actions expected from a student in simulations or learning trajectories as projected by a teacher, inside an intelligent tutoring system, or even in a game—or it can simply be used for a set of student clicks, button selections, or keyboard hits expected to reach a correct answer. This solution provides flexibility for existing automatic‐scoring techniques and potentially could provide more flexibility if coupled with statistical data‐mining techniques.
LENGTH OF TEXTUAL RESPONSE AS A CONSTRUCT‐IRRELEVANT RESPONSE STRATEGY: THE CASE OF SHELL LANGUAGE
Authors: Bejar Isaac I. , VanWinkle Waverely , Madnani Nitin , Lewis William , Steier Michael
Published: August 2014

The paper applies a natural language computational tool to study a potential construct‐irrelevant response strategy, namely the use of shell language. Although the study is motivated by the impending increase in the volume of scoring of students responses from assessments to be developed in response to the Race to the Top initiative, the data for the study were obtained from the GRE® Analytical Writing measure. The functioning of the shell detection computational tool was first evaluated by applying it to a corpus of over 200,000 issue and argument essays and by means of a study to evaluate whether the shell language score agreed with the characterization of shell by two scoring experts. It was concluded that the computational tool worked well. The tool was then used to select essays for rescoring to determine whether the presence of shell language had had an effect on the operational scores they received. We found no evidence that such an effect was present. However, we did find a leniency effect in the operational scores. That is, the essays that were rescored as part of this project received a lower score compared to the operational score. The validity implications of these results are discussed.
IDENTIFYING THE MOST IMPORTANT 21ST CENTURY WORKFORCE COMPETENCIES: AN ANALYSIS OF THE OCCUPATIONAL INFORMATION NETWORK (O*NET)
Authors: Burrus Jeremy , Jackson Teresa , Xi Nuo , Steinberg Jonathan
Published: August 2014

To identify the most important competencies for college graduates to succeed in the 21st century workforce, we conducted an analysis of the Occupational Information Network (O*NET) database. O*NET is a large job analysis operated and maintained by the U.S. Department of Labor. We specifically analyzed ratings of the importance of abilities (52 ratings), work styles (16 ratings), skills (35 ratings), and knowledge (33 ratings) to succeed in one's occupation. First, we conducted descriptive analyses. Next, data were split into 2 sets, according to the theoretical structure proposed by the O*NET content model, and principal component analyses (PCAs) were run on each dataset. The PCAs identified 15 components: problem solving, mechanical skills, service orientation, cultural literacy, business literacy, science literacy, civic literacy, information processing, athleticism, visual acuity, fluid intelligence, communication skills, teamwork, achievement/innovation, and attention to detail/near vision. Components were then ranked in importance using the mean component scores over all occupations. A comparison of this ranking with previous 21st century competencies frameworks suggested that 5 competencies stand out as important for most occupations: problem solving (e.g., complex problem solving), fluid intelligence (e.g., category flexibility), teamwork (e.g., cooperation), achievement/innovation (e.g., persistence), and communication skills (e.g., oral expression). Consistent with this conclusion, a correlation of component scores with wages found that 4 of these 5 competencies were strongly related to wages, with the exception being teamwork.
EXAMINING THE EFFICACY OF A TIME MANAGEMENT INTERVENTION FOR HIGH SCHOOL STUDENTS
Authors: Burrus Jeremy , Jackson Teresa , Holtzman Steven , Roberts Richard D. , Mandigo Terri
Published: August 2014

The current paper reports the results of 2 quasiexperimental studies conducted to examine the efficacy of a new time management intervention designed for high school students. In both studies, there was no difference between the treatment and control groups in improvement in self‐reported time management skills as a result of the intervention. However, the treatment group reported significantly greater improvement than the control group for secondary outcomes such as stress (Studies 1 and 2), anxiety (Studies 1 and 2), depression (Study 1), and knowledge of time management strategies (Study 1). Additionally, advisor ratings of student time management skills were higher for the treatment than for the control group in Study 2. Implications and suggestions for improving the intervention are discussed.
CONSTRUCTED‐RESPONSE DIF EVALUATIONS FOR MIXED‐FORMAT TESTS
Authors: Moses Tim , Liu Jinghua , Tan Adele , Deng Weiling , Dorans Neil J.
Published: August 2014

In this study, differential item functioning (DIF) methods utilizing 14 different matching variables were applied to assess DIF in the constructed‐response (CR) items from 6 forms of 3 mixed‐format tests. Results suggested that the methods might produce distinct patterns of DIF results for different tests and testing programs, in that the DIF methods' results might be similar for tests with multiple‐choice (MC) and CR scores that are similar in their measurement characteristics but would exhibit larger variations for tests with MC and CR scores having more distinct measurement characteristics. Impact measures of the MC and CR scores appeared to be a useful basis for indicating the scores' measurement similarity, for predicting the variations of DIF results from using these scores as matching variables, and possibly for indicating the most appropriate DIF method and matching variable for a particular test. The results are described in terms of their implications for research and practice.
COLLABORATIVE PROBLEM SOLVING AND THE ASSESSMENT OF COGNITIVE SKILLS: PSYCHOMETRIC CONSIDERATIONS
Authors: von Davier Alina A. , Halpin Peter F.
Published: August 2014

Collaboration is generally recognized as a core competency of today's knowledge economy and has taken a central role in recent theoretical and technological developments in education research. Yet, the methodology for assessing the learning benefits of collaboration continues to rely on educational tests designed for isolated individuals. Thus, what counts as evidence of learning does not correspond to current best practices for teaching, and it does not reflect what students are ultimately expected to be able to do with their knowledge. The goals of this paper are to give an overview of the research conducted in several fields of work related to collaboration, propose a framework for the assessment of cognitive skills (such as science or math) through collaborative problem‐solving tasks, and propose several statistical approaches to model the data collected from collaborative interactions. This research contributes to the knowledge needed to support a new generation of assessments based on collaboration.
Mutant disrupted‐in‐schizophrenia 1 in astrocytes: Focus on glutamate metabolism
Authors: Abazyan Sofya , Yang Eun Ju , Abazyan Bagrat , Xia Meng , Yang Chunxia , Rojas Camilo , Slusher Barbara , Sattler Rita , Pletnikov Mikhail
Published: August 2014

Disrupted‐in‐schizophrenia 1 (DISC1) is a genetic risk factor that has been implicated in major mental disorders. DISC1 binds to and stabilizes serine racemase to regulate production of D‐serine by astrocytes, contributing to glutamate (GLU) neurotransmission. However, the possible involvement of astrocytic DISC1 in synthesis, metabolism, reuptake, or secretion of GLU remains unexplored. Therefore, we studied the effects of dominant‐negative mutant DISC1 on various aspects of GLU metabolism by using primary astrocyte cultures and hippocampal tissue from transgenic mice with astrocyte‐restricted expression of mutant DISC1. Although mutant DISC1 had no significant effects on astrocyte proliferation, GLU reuptake, glutaminase, or glutamate carboxypeptidase II activity, expression of mutant DISC1 was associated with increased levels of alanine‐serine‐cysteine transporter 2, vesicular glutamate transporters 1 and 3 in primary astrocytes and in the hippocampus, and elevated expression of the NR1 subunit and diminished expression of the NR2A subunit of N‐methyl‐D‐aspartate (NMDA) receptors in the hippocampus, at postnatal day 21. Our findings indicate that decreased D‐serine production by astrocytic mutant DISC1 might lead to compensatory changes in levels of the amino acid transporters and NMDA receptors in the context of tripartite synapse. © 2014 Wiley Periodicals, Inc.
Volcanic stratigraphy of the Quaternary La Garrotxa Volcanic Field (north‐east Iberian Peninsula)
Authors: BOLÓS XAVIER , PLANAGUMÀ LLORENÇ , MARTÍ JOAN
Published: August 2014

The monogenetic Quaternary La Garrotxa Volcanic Field forms part of the Catalan Volcanic Zone (north‐east Iberian Peninsula), one of the alkaline volcanic provinces of the European rift system. It harbours more than 50 basaltic monogenetic cones that range in age from the Middle Pleistocene to the Early Holocene and include cinder and scoria cones, lava flows, tuff rings and maars. This study is the result of extensive fieldwork, including the study of ephemeral outcrops and the stratigraphic logging of new water wells and geotechnical drill holes, also taking into account existing information gathered by recent geophysical studies that have applied shallow geophysical methods to establish the substrate geology of this volcanic field. We have obtained a comprehensive volcanic stratigraphy of the area that identifies the products of each single eruption, their relative stratigraphy and their surface area. This volcanic stratigraphy constitutes an essential tool for understanding the evolution of this volcanic field and for establishing a correct volcanic hazard assessment for the area, but it also provides a precise reference for the Quaternary tephrochronology of the lake sediments in neighbouring areas.
Characterization of enzymatically prepared sugar medium‐chain fatty acid monoesters
Authors: Zhang Xi , Wei Wei , Cao Xi , Feng Fengqin
Published: August 2014

BACKGROUND

Sugar medium‐chain fatty acid esters are a new type of biodegradable, non‐toxic, non‐irritant and non‐ionic surfactant with proven antimicrobial activity. Various sugar medium‐chain fatty monoesters were prepared enzymatically using Lipozyme TLIM in organic solvent. Properties such as surface tension, antimicrobial activity, and ability to foam, emulsify and stabilize emulsions at room temperature were evaluated to conduct systematic studies on the structure–function relationships of these compounds.

RESULTS

Results showed that all monoesters displayed good surface activity properties. In particular, sucrose monolaurate was the most excellent surfactant among 12 monoesters. Sugar monoesters containing C8 to C12 alkyl chains showed a broad spectrum of increasing antimicrobial activity. All tested monoesters were more effective against Staphylococcus aureus (Gram‐positive bacterium) than Escherichia coli O157:H7 (Gram‐negative bacterium). Methyl α‐d‐glycoside monoesters were the most effective, whereas raffinose monoesters possessed poor antimicrobial activity.

CONCLUSIONS

Generally, the length of fatty acid chain (hydrophobic group) and sugar groups (hydrophilic group) for sugar medium‐chain fatty acid monoesters both affected the surface properties and antimicrobial activities. © 2014 Society of Chemical Industry
Simultaneous determination of 7‐O‐succinyl macrolactin A and its active major metabolite, macrolactin A in dog plasma using high‐performance liquid chromatography with UV detection
Authors: Kim Eunyoung , Shin Beomsoo , Kwon Kwang‐il , Bang Joon Seok , Kang Wonku
Published: August 2014

We developed a method for the simultaneous quantification of 7‐O‐succinyl macrolactin A and its active metabolite, macrolactin A, in dog plasma. After protein precipitation with acetonitrile including flufenamic acid as an internal standard, 7‐O‐succinyl macrolactin A, macrolactin A, and flufenamic acid were chromatographed on a reverse‐phase C18 analytical column. The mobile phase, consisting of 20 mM acetate buffer and acetonitrile, was eluted using a gradient program at 1 mL/min, and the UV absorbance was measured at 230 nm. The retention times of 7‐O‐succinyl macrolactin A, flufenamic acid, and macrolactin A were 3.4, 4.8, and 6.9 min, respectively. The coefficient of variation in the assay precision for both substances was less than 6%, and the accuracy ranged from 96 to 105%. This method was used to measure the concentrations of 7‐O‐succinyl macrolactin A and macrolactin A in dog plasma following an intravenous administration of a single dose (25 mg/kg) of 7‐O‐succinyl macrolactin A salt.
Open Innovation in Universities: The Relationship Between Innovation and Commercialisation
Authors: Abdul Razak Arbaiah , Murray Peter A. , Roberts David
Published: August 2014

Increasing calls from university stakeholders to optimise innovation capabilities has never been more urgent given the increasing link between industry and universities. However, innovation activities that underpin the commercialisation attempts of universities are seldom translated into commercialisation success. This is mainly attributed to poor management of innovation processes between innovation networks. Empirical evidence indicates that trust relationships between innovation actors are difficult to achieve because of the perceived risk of disclosure, managerial complexity and conflicts of culture. The purpose of this review paper is to examine how open innovation within universities enhances innovation practices that lead to commercialisation success. Other connecting variables that embody trust, motivation to innovate and strategic leadership are equally important. Several hypotheses are developed, and a research model connects the innovation constructs. This paper is expected to make a significant contribution to connecting literatures that inform successful university‐led and industry‐led partnerships. Copyright © 2014 John Wiley & Sons, Ltd.
Naïve Responses to Kind Delegation
Authors: Eisenkopf Gerald , Fischbacher Urs
Published: August 2014

People do not like to delegate the distribution of favors. To explain this reluctance, we disentangle reward motives in an experiment in which an investor can directly transfer money to a trustee or delegate this decision to another investor. Varying the transfer values of the investor and delegate, we find that the trustee's rewards follow a rather simple pattern. In all situations, both investors are rewarded, but the person who ultimately decides gets a higher reward. Unlike studies on the punishment of delegated unkind decisions, our results do not reveal a more sophisticated reward behavior that takes people's responsibility into account. Copyright © 2014 John Wiley & Sons, Ltd.
Terminal osseous dysplasia with pigmentary defects (TODPD) due to a recurrent filamin A (FLNA) mutation
Authors: Brunetti‐Pierri Nicola , Torrado Maria , Fernandez Maria del Carmen , Tello Ana Maria , Arberas Claudia L. , Cardinale Antonella , Piccolo Pasquale , Bacino Carlos A.
Published: August 2014

Terminal osseous dysplasia with pigmentary defects (TODPD) is an X‐linked dominant syndrome with distal limb anomalies, pigmentary skin defects, digital fibromas, and generalized bone involvement due to a recurrent mutation in the filamin A (FLNA) gene. We here report the mutation c.5217G>A in FLNA in three families with TODPD and we found possible germline and somatic mosaicism in two out of the three families. The occurrence of somatic and germline mosaicism for TODPD indicates that caution should be taken in counseling recurrence risks for these conditions upon presentation of an isolated case.
Measurement of T1 relaxation time of osteochondral specimens using VFA‐SWIFT
Authors: Nissi Mikko J. , Lehto Lauri J. , Corum Curtis A. , Idiyatullin Djaudat , Ellermann Jutta M. , Gröhn Olli H.J. , Nieminen Miika T.
Published: August 2014

Purpose

To evaluate the feasibility of SWIFT with variable flip angle (VFA) for measurement of T1 relaxation time in Gd‐agarose‐phantoms and osteochondral specimens, including regions of very short T2*, and compare with T1 measured using standard methods

Methods

T1s of agarose phantoms with variable concentration of Gd‐DTPA2− and nine pairs of native and trypsin‐treated bovine cartilage‐bone specimens were measured. For specimens, VFA‐SWIFT, inversion recovery (IR) fast spin echo (FSE) and saturation recovery FSE were used. For phantoms, additionally spectroscopic IR was used. Differences and agreement between the methods were assessed using nonparametric Wilcoxon and Kruskal‐Wallis tests and intraclass correlation.

Results

The different T1 mapping methods agreed well in the phantoms. VFA‐SWIFT allowed reliable measurement of T1 in the osteochondral specimens, including regions where FSE‐based methods failed. The T1s measured by VFA‐SWIFT were shifted toward shorter values in specimens. However, the measurements correlated significantly (highest correlation VFA‐SWIFT versus FSE was r = 0.966). SNR efficiency was generally highest for SWIFT, especially in the subchondral bone.

Conclusion

Feasibility of measuring T1 relaxation time using VFA‐SWIFT in osteochondral specimens and phantoms was demonstrated. A shift toward shorter T1s was observed for VFA‐SWIFT in specimens, reflecting the higher sensitivity of SWIFT to short T2* spins. Magn Reson Med 74:175–184, 2015. © 2014 Wiley Periodicals, Inc.
Accelerated cardiac MR stress perfusion with radial sampling after physical exercise with an MR‐compatible supine bicycle ergometer
Authors: Pflugi Silvio , Roujol Sébastien , Akçakaya Mehmet , Kawaji Keigo , Foppa Murilo , Heydari Bobby , Goddu Beth , Kissinger Kraig , Berg Sophie , Manning Warren J. , Kozerke Sebastian , Nezafat Reza
Published: August 2014

Purpose

To evaluate the feasibility of accelerated cardiac MR (CMR) perfusion with radial sampling using nonlinear image reconstruction after exercise on an MR‐compatible supine bike ergometer.

Methods

Eight healthy subjects were scanned on two separate days using radial and Cartesian CMR perfusion sequences in rest and exercise stress perfusion. Four different methods (standard gridding, conjugate gradient SENSE [CG‐SENSE], nonlinear inversion with joint estimation of coil‐sensitivity profiles [NLINV] and compressed sensing with a total variation constraint [TV]) were compared for the reconstruction of radial data. Cartesian data were reconstructed using SENSE. All images were assessed by two blinded readers in terms of image quality and diagnostic value.

Results

CG‐SENSE and NLINV were scored more favorably than TV (in both rest and stress perfusion cases, P < 0.05) and gridding (for rest perfusion cases, P < 0.05). TV images showed patchy artifacts, which negatively influenced image quality especially in the stress perfusion images acquired with a low number of radial spokes. Although CG‐SENSE and NLINV received better scores than Cartesian sampling in both rest and exercise stress perfusion cases, these differences were not statistically significant (P > 0.05).

Conclusion

We have demonstrated the feasibility of accelerated CMR perfusion using radial sampling after physical exercise using a supine bicycle ergometer in healthy subjects. For reconstruction of undersampled radial perfusion, CG‐SENSE and NLINV resulted in better image quality than standard gridding or TV reconstruction. Further technical improvements and clinical assessment are needed before using this approach in patients with suspected coronary artery disease. Magn Reson Med 74:384–395, 2015. © 2014 Wiley Periodicals, Inc.
Less noise, more activation: Multiband acquisition schemes for auditory functional MRI
Authors: De Martino Federico , Moerel Michelle , Ugurbil Kamil , Formisano Elia , Yacoub Essa
Published: August 2014

Purpose

To improve acquisition in fMRI studies of audition by using multiband (MB) gradient‐echo echo planar imaging (GE‐EPI).

Methods

Data were acquired at 3T (Siemens Skyra) with a 32‐channel head coil. Functional responses were obtained by presenting stimuli [tones and natural sounds (voices, speech, music, tools, animal cries)] in silent gaps between image acquisitions. Two‐fold slice acceleration (MB2) was compared with a standard GE‐EPI (MB1). Coverage and sampling rate (TR = 3 s) were kept constant across acquisition schemes. The longer gap in MB2 scans was used to present: (i) sounds of the same length as in conventional GE‐EPI (type 1; 800 ms stimuli); (ii) sounds of double the length (type 2; 1600 ms stimuli).

Results

Functional responses to all sounds (i.e., main effect) were stronger when acquired with slice acceleration (i.e., shorter acquisition time). The difference between voice and nonvoice responses was greater in MB2 type 1 acquisitions (i.e., same length sounds as GE‐EPI but presented in a longer silent gap) than in standard GE‐EPI acquisitions (interaction effect).

Conclusion

Reducing the length of the scanner noise results in stronger functional responses. Longer “silent” periods (i.e., keeping the sound length the same as in standard acquisitions) result in stronger response to voice compared with nonvoice stimuli. Magn Reson Med 74:462–467, 2015. © 2014 Wiley Periodicals, Inc.
Dielectric relaxation studies of some poly(ether imide)s containing main‐chain ethyleneoxide units
Authors: Eastmond G. C. , Paprotny J. , Pawson A. , Pethrick R. A. , Santamaria‐Mendia F.
Published: August 2014

Broad band dielectric relaxation spectra are reported for some poly(ether imide)s based on 2,2‐bis[4′‐(3″,4″‐dicarboxyphenoxy)phenyl]hexafluoropropane dianhydride and 1,2‐bis(4‐aminophenyl) diamines derived from ethylene glycol oligomers of different specific lengths. Spectra were obtained over the temperature range −150–−20 °C and which covers the low temperature relaxation region for these materials. In the case of the polymer with no EO units, a single broad dipole relaxation feature is observed. The introduction of a single CH2CH2O unit significantly broadens the relaxation suggesting the existence of two separate relaxation processes. Increasing the number of EO units per repeat to 3 and 6, allows resolution of two relaxations processes; one due to an oscillatory–librational motion of the imide segment and the other to conformational changes involving the EO sequences. Analysis of the relaxation using the Havriliak‐Negami equation indicates that both processes deviate for the description of a simple dipole relaxation and indicate cooperativity of bond motion in the relaxation process. The ability of a polymer to change its packing density is reflected in changes in the relaxation spectra on annealing and changes in the value of the higher frequency limiting values of the permittivity. The activation energy for dipole reorientation ranges from a value of 34 kJ mol−1 for the relaxation of the dipole associated with the imide relaxation process to a value of 60 kJ mol−1 for the polymer containing 3 EO segments. In this latter polymer, system a lower activation energy process is observed with a magnitude of ∼15 kJ mol−1 associated with conformational changes of the aliphatic ether. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 1326–1336
Determination of the single crystal Ge Young’s modulus between room temperature and melting temperature using the impulse excitation technique
Authors: Swarnakar Akhilesh K. , Van der Biest Omer , Van Humbeeck Jan , Vanhellemont Jan
Published: August 2014

In the present study, the vibrational properties of single crystal Ge samples are studied between room and melt‐ing temperature using the impulse excitation technique (IET). From the IET measurements, the temperature dependent Young's moduli Eijk of single crystal Ge are extracted in the (100), (110) and (111) crystallographic directions in inert atmosphere.

The results show an anomalous softening of an elastic constant around 890 °C temperature during the measure‐ment. The Young's moduli values between 88 to 132 GPa are obtained close to the melting temperature, depending on the crystallographic direction. Empiric expressions are derived for the temperature dependence of E(100), E(110) and E(111). (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High dose proton implantations into silicon: a combined EBIC, SRP and TEM study
Authors: Kirnstoetter Stefan , Faccinelli Martin , Gspan Christian , Grogger Werner , Jelinek Moriz , Schustereder Werner , Laven Johannes G. , Schulze Hans‐Joachim , Hadley Peter
Published: August 2014

Proton (H+) implantations are used in power semiconductor devices to introduce recombination centers (Hazdra et al., Microelectron. J. 32(5), 449–456 (2001)) or to form hydrogen related donor complexes (Zohta et al., Jpn. J. Appl. Phys. 10, 532–533 (1991)). Proton implantations are also used in the 'smart cut' process to generate defects that can be used to cleave thin wafers (Romani and Evans, Nucl. Instrum. Methods Phys. Res. B 44, 313–317 (1990)). However, the implantation damage resulting from H+implantations is not completely understood. In this study, protons with energies from 400 keV up to 4 MeV and doses up to 1016 H+/cm² were implanted into highly ohmic boron doped m:Cz silicon (100). Electron Beam Induced Current (EBIC) measurements were performed to locally determine the minority charge carrier diffusion length. The diffusion length decreases with increasing implantation dose and incorporated damage. Spreading Resistance Profiling (SRP) measurements were performed to analyze the charge carrier concentration profiles for different annealing procedures. The electrical activation and growth of the defect complexes varies strongly with the annealing parameters. Transmission Electron Microscopy measurements were made to investigate the microscopic structures formed by the high dose implantation processes. Due to the high local damage density resulting from low energy and high dose H+ implants, platelet structures are formed. During high‐energy high‐dose H+implantations, the implanted hydrogen generates strain in the crystal lattice resulting in changes in the distances between atomic planes. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sol–gel deposited phosphorus and boron doped thin silica films for diffused n+p and n+pp+ structures
Authors: Pene Armel Duvalier , Hartiti Bouchaib , Bitjoka Laurent , Thevenin Phillippe , Kapseu Cesar
Published: August 2014

The realization of a silicon solar cell emitter is a critical and very important step in photovoltaic technology. Indeed, the surface concentration of boron (B) or phosphorus (P) and junction depth determines the photovoltaic conversion efficiency of silicon solar cells. Several techniques are used for the realization of emitters n+p and n+pp+ among which the vapor diffusion, ionic implantation and diffusion from solid sources are the most common. This work will be devoted to the realization of emitters made by diffusion of P or B from solid doping sources developed by the sol–gel method associated to spin coating on monocrystalline and polycrystalline silicon wafers. The doping solutions were prepared by sol–gel method using methyltriethoxysilane “MTEOS” or tetramethoxysilane “TEOS” and H4PO3 or H3BO3 as precursors. The n+ junction was realized by emulsion of phosphoric acid in isopropanol while the p+ junction was obtained by emulsion of boric acid H3BO3 in isopropanol or by diffusion of aluminium at high temperatures. Our samples were annealed at temperatures ranging from 850 to 1000 °C in a classical furnace under Nitrogen atmosphere. The four point technique has been used to study the electrical properties of n+p and n+pp++ structures. The results of measurements showed values of the sheet resistance Rs comparable to those of literature and confirm the diffusion of phosphorus and boron from liquid and solid sources prepared by sol–gel method. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Bayesian Approach to Sequential Optimization based on Computer Experiments
Authors: Tajbakhsh Sam Davanloo , del Castillo Enrique , Rosenberger James L.
Published: August 2014

Computer experiments are used frequently for the study and improvement of a process under study. Optimizing such process based on a computer model is costly, so an approximation of the computer model, or metamodel, is used. Efficient global optimization (EGO) is a sequential optimization method for computer experiments based on a Gaussian process model approximation to the computer model response. A long‐standing problem in EGO is that it does not consider the uncertainty in the parameter estimates of the Gaussian process. Treating these estimates as if they are the true parameters leads to an improper assessment of the precision of the approximation, a precision that is crucial to assess not only in optimization but in metamodeling in general. One way to account for these uncertainties is to use bootstrapping, studied by previous authors. Alternatively, some other authors have mentioned how a Bayesian approach may be the best way to incorporate the parameter uncertainty in the optimization, but no fully Bayesian approach for EGO has been implemented in practice. In this paper, we present a fully Bayesian implementation of the EGO method. The proposed Bayesian EGO algorithm is validated through simulation of noisy nonlinear functions and compared with the standard EGO method and the bootstrapped EGO. We also apply the Bayesian EGO algorithm to the optimization of a stochastic computer model. It is shown how a Bayesian approach to EGO allows one to optimize any function of the posterior predictive density. Copyright © 2014 John Wiley & Sons, Ltd.
Chemistry and sputtering induced by fullerene and argon clusters in carbon‐based materials
Authors: Czerwinski Bartlomiej , Delcorte Arnaud
Published: August 2014

Classical MD computer simulations are used as a tool for the theoretical investigation of the processes initiated in carbon‐based materials by the irradiation with C60 and Arn clusters. This paper shows the comparison of data regarding the chemical reactions occurring in polystyrene and fullerite bombarded by C60 and Arn projectiles with the initial energy of 2.5 and 10 keV. Its main focus is to elucidate the influence of material type on the bond breaking as new bond formation processes induced by impinging cluster projectiles. Copyright © 2014 John Wiley & Sons, Ltd.
Manganese Doped Fluorescent Paramagnetic Nanocrystals for Dual‐Modal Imaging
Authors: Sharma Vijay Kumar , Gokyar Sayim , Kelestemur Yusuf , Erdem Talha , Unal Emre , Demir Hilmi Volkan
Published: August 2014

In this work, dual‐modal (fluorescence and magnetic resonance) imaging capabilities of water‐soluble, low‐toxicity, monodisperse Mn‐doped ZnSe nanocrystals (NCs) with a size (6.5 nm) below the optimum kidney cutoff limit (10 nm) are reported. Synthesizing Mn‐doped ZnSe NCs with varying Mn2+ concentrations, a systematic investigation of the optical properties of these NCs by using photoluminescence (PL) and time resolved fluorescence are demonstrated. The elemental properties of these NCs using X‐ray photoelectron spectroscopy and inductive coupled plasma‐mass spectroscopy confirming Mn2+ doping is confined to the core of these NCs are also presented. It is observed that with increasing Mn2+ concentration the PL intensity first increases, reaching a maximum at Mn2+ concentration of 3.2 at% (achieving a PL quantum yield (QY) of 37%), after which it starts to decrease. Here, this high‐efficiency sample is demonstrated for applications in dual‐modal imaging. These NCs are further made water‐soluble by ligand exchange using 3‐mercaptopropionic acid, preserving their PL QY as high as 18%. At the same time, these NCs exhibit high relaxivity (≈2.95 mM−1 s−1) to obtain MR contrast at 25 °C, 3 T. Therefore, the Mn2+ doping in these water‐soluble Cd‐free NCs are sufficient to produce contrast for both fluorescence and magnetic resonance imaging techniques.
Writing and Functionalisation of Suspended DNA Nanowires on Superhydrophobic Pillar Arrays
Authors: Miele Ermanno , Accardo Angelo , Falqui Andrea , Marini Monica , Giugni Andrea , Leoncini Marco , De Angelis Francesco , Krahne Roman , Di Fabrizio Enzo
Published: August 2014

Nanowire arrays and networks with precisely controlled patterns are very interesting for innovative device concepts in mesoscopic physics. In particular, DNA templates have proven to be versatile for the fabrication of complex structures that obtained functionality via combinations with other materials, for example by functionalisation with molecules or nanoparticles, or by coating with metals. Here, the controlled motion of the a three‐phase contact line (TCL) of DNA‐loaded drops on superhydrophobic substrates is used to fabricate suspended nanowire arrays. In particular, the deposition of DNA wires is imaged in situ, and different patterns are obtained on hexagonal pillar arrays by controlling the TCL velocity and direction. Robust conductive wires and networks are achieved by coating the wires with a thin layer of gold, and as proof of concept conductivity measurements are performed on single suspended wires. The plastic material of the superhydrophobic pillars ensures electrical isolation from the substrate. The more general versatility of these suspended nanowire networks as functional templates is outlined by fabricating hybrid organic–metal–semiconductor nanowires by growing ZnO nanocrystals onto the metal‐coated nanowires.
Rapid Determination of Olive Oil Chlorophylls and Carotenoids by Using Visible Spectroscopy
Authors: Cayuela José A. , Yousfi Khaled , Carmen Martínez M. , García José M.
Published: August 2014

The determination of total chlorophylls and total carotenoids in olive oil by using visible spectroscopy (VIS) is reported. The proposed technique has been compared with the determination of these pigments by near infrared spectroscopy (NIRS) and VIS together with NIRS. Several procedures for multivariate regression were tested. The reference methods used were the determination of the extinction coefficient K670 for total chlorophylls and K470 for total carotenoids. A total of 258 samples were tested. The optimization of the calibration for total chlorophylls was set by using multiple linear regression (MLR) from the wavelengths 670–686 nm exclusively visible. Its satisfactory performance was proven from the model coefficients standard error of calibration SEC 2.63 and R2 0.97, and the residual predictive deviation (RPD) 5.76 from the external validation. For the total carotenoids the best VIS calibration was fit by using the window of 465–475 nm and partial least squares (PLS), which provided an RPD of 3.68. However, the model built using the entire spectrum VIS‐NIRS available (350–2,500 nm) was slightly better for this last pigment, showing an RPD of 3.86. Hence, this study showed that the proposed VIS technique can be advantageous for the determination of total chlorophylls in olive oils while it is also suitable for determining total carotenoids.
Coding causal–noncausal verb alternations: A form–frequency correspondence explanation
Authors: HASPELMATH MARTIN , CALUDE ANDREEA , SPAGNOL MICHAEL , NARROG HEIKO , BAMYACI ELİF
Published: August 2014

We propose, and provide corpus-based support for, a usage-based explanation for cross-linguistic trends in the coding of causal–noncausal verb pairs, such asraise/rise, break(tr.)/break(intr.). While English mostly uses the same verb form both for the causal and the noncausal sense (labile coding), most languages have extra coding for the causal verb (causative coding) and/or for the noncausal verb (anticausative coding). Causative and anticausative coding is not randomly distributed (Haspelmath 1993): Some verb meanings, such as ‘freeze’, ‘dry’ and ‘melt’, tend to be coded as causatives, while others, such as ‘break’, ‘open’ and ‘split’, tend to be coded as anticausatives. We propose an explanation of these coding tendencies on the basis of the form–frequency correspondence principle, which is a general efficiency principle that is responsible for many grammatical asymmetries, ultimately grounded in predictability of frequently expressed meanings. In corpus data from seven languages, we find that verb pairs for which the noncausal member is more frequent tend to be coded as anticausatives, while verb pairs for which the causal member is more frequent tend to be coded as causatives. Our approach implies that linguists should not rely on form–meaning parallelism when trying to explain cross-linguistic or language-particular patterns in this domain.
Does GenBank provide a reliable DNA barcode reference to identify small alien oysters invading the Mediterranean Sea?
Authors: Crocetta F. , Mariottini P. , Salvi D. , Oliverio M.
Published: August 2014

The Mediterranean Sea is currently under siege by a conspicuous alien pressure, and, within some families (e.g. the Ostreidae), the number of native species seems to be remarkably outnumbered by that of the alien ones. We wanted to test the reliability of the molecular data currently available on the small alien oysters recently invading the Mediterranean Sea. Samples from Greece and Turkey, encompassing the known species-specific morphological variation, were sequenced for the markers with the widest taxonomic coverage in the group of small oysters (i.e. the 16S rDNA and the COI). The sequences obtained have been compared with those available in GenBank, and a possible identification at the species level has been finally tested in a DNA-barcoding fashion. The present results clearly demonstrated that our samples belong to a single, morphologically highly variable species. Their 16S sequences were closely related to a sequence registered under the nameDendostrea folium, with a genetic distance which does not warrant conspecificity. Additionally, a remarkable number of sequences retrieved from the GenBank (of both genes) did not form a monophyletic group according to the published classification of the vouchers, suggesting—at least in part—an origin from specimens not properly identified. Both genes seem promising for use as DNA-barcode, although the COI will probably prove more effective. Therefore, we urge the availability of a baseline of oyster pedigreed DNA barcode sequences in the public databases, to allow the use of such genetic data to reliably monitor bio-invasions in the Mediterranean Sea.
Grouping of large populations into few CTL immune ‘response‐types’ from influenza H1N1 genome analysis
Authors: Mukherjee Sumanta , Chandra Nagasuma
Published: August 2014

Despite extensive work on influenza, a number of questions still remain open about why individuals are differently susceptible to the disease and why only some strains lead to epidemics. Here we study the effect of human leukocyte antigen (HLA) genotype heterogeneity on possible cytotoxic T‐lymphocyte (CTL) response to 186 influenza H1N1 genomes. To enable such analysis, we reconstruct HLA genotypes in different populations using a probabilistic method. We find that epidemic strains in general correlate with poor CTL response in populations. Our analysis shows that large populations can be classified into a small number of groups called response‐types, specific to a given viral strain. Individuals of a response‐type are expected to exhibit similar CTL responses. Extent of CTL responses varies significantly across different populations and increases with increase in genetic heterogeneity. Overall, our analysis presents a conceptual advance towards understanding how genetic heterogeneity influences disease susceptibility in individuals and in populations. We also obtain lists of top‐ranking epitopes and proteins, ranked on the basis of conservation, antigenic cross‐reactivity and population coverage, which provide ready short‐lists for rational vaccine design. Our method is fairly generic and has the potential to be applied for studying other viruses.
Synovial fluid myeloid dendritic cells display important differences compared to monocyte‐derived dendritic cells prepared in vitro
Authors: Moghaddami Mahin , James Michael , Whittle Samuel L , Cleland Leslie G
Published: August 2014

The object of this study was to characterise synovial fluid dendritic cells (SFDCs) with regard to morphology, phenotype and responses to 1,25hydroxy‐cholecalciferol (1,25D) and lipopolysaccharide (LPS), and to compare these characteristics with those of peripheral blood (PB) monocyte‐derived DCs (MDDCs). SF was aspirated from knees with inflammatory effusions. PB samples were obtained contemporaneously. SFDCs were separated by flow cytometry. Morphology was determined on cytosmears. Expression of accessory molecules, cytokines and prostaglandin synthases mRNA was quantified by reverse transcription PCR. Analyses were performed on freshly prepared DCs and after incubation with 1,25D and LPS, separately and in combination. SFDCs and MDDCs displayed broadly similar morphology. Expression of accessory molecules, cytokines, cyclooxygenase‐2 (COX‐2) and prostaglandin E‐synthase (PGES) was similar. SFDCs, but not MDDCs, expressed prostaglandin D‐synthase (PGDS). PGDS was lost on incubation with SFDCs, but was induced by 1,25D in MDDCs. LPS in the presence or absence of 1,25D, induced interleukin 23 (IL23), IL1β and tumour necrosis factor‐α in SFDCs and MDDCs, with SFDC showing stronger expression of these cytokines. 1,25D in combination with LPS induced PGES and enhanced LPS induction of IL6 in SFDCs and MDDCs. LPS reduced 1,25D‐induced expression of PGDS in MDDCs. SFDCs and MDDCs display similar basal characteristics but differ in PGDS expression and responsiveness to LPS and 1,25D. MDDCs have limitations as a model of SFDCs which have differentiated in vivo.
Physicochemical impacts associated with natural gas development on methanogenesis in deep sand aquifers
Authors: Katayama Taiki , Yoshioka Hideyoshi , Muramoto Yoshiyuki , Usami Jun , Fujiwara Kazuhiro , Yoshida Satoshi , Kamagata Yoichi , Sakata Susumu
Published: August 2014

The Minami-Kanto gas field, where gases are dissolved in formation water, is a potential analogue for a marine gas hydrate area because both areas are characterized by the accumulation of microbial methane in marine turbidite sand layers interbedded with mud layers. This study examined the physicochemical impacts associated with natural gas production and well drilling on the methanogenic activity and composition in this gas field. Twenty-four gas-associated formation water samples were collected from confined sand aquifers through production wells. The stable isotopic compositions of methane in the gases indicated their origin to be biogenic via the carbonate reduction pathway. Consistent with this classification, methanogenic activity measurements using radiotracers, culturing experiments and molecular analysis of formation water samples indicated the predominance of hydrogenotrophic methanogenesis. The cultivation of water samples amended only with methanogenic substrates resulted in significant increases in microbial cells along with high-yield methane production, indicating the restricted availability of substrates in the aquifers. Hydrogenotrophic methanogenic activity increased with increasing natural gas production from the corresponding wells, suggesting that the flux of substrates from organic-rich mudstones to adjacent sand aquifers is enhanced by the decrease in fluid pressure in sand layers associated with natural gas/water production. The transient predominance of methylotrophic methanogens, observed for a few years after well drilling, also suggested the stimulation of the methanogens by the exposure of unutilized organic matter through well drilling. These results provide an insight into the physicochemical impacts on the methanogenic activity in biogenic gas deposits including marine gas hydrates.
Imaging the dynamics of free-electron Landau states
Authors: Schattschneider P. , Schachinger Th. , Stöger-Pollach M. , Löffler S. , Steiger-Thirsfeld A. , Bliokh K. Y. , Nori Franco
Published: August 2014

Landau levels and states of electrons in a magnetic field are fundamental quantum entities underlying the quantum Hall and related effects in condensed matter physics. However, the real-space properties and observation of Landau wave functions remain elusive. Here we report the real-space observation of Landau states and the internal rotational dynamics of free electrons. States with different quantum numbers are produced using nanometre-sized electron vortex beams, with a radius chosen to match the waist of the Landau states, in a quasi-uniform magnetic field. Scanning the beams along the propagation direction, we reconstruct the rotational dynamics of the Landau wave functions with angular frequency ~100 GHz. We observe that Landau modes with different azimuthal quantum numbers belong to three classes, which are characterized by rotations with zero, Larmor and cyclotron frequencies, respectively. This is in sharp contrast to the uniform cyclotron rotation of classical electrons, and in perfect agreement with recent theoretical predictions.
Single Molecule Investigation of Ag+ Interactions with Single Cytosine-, Methylcytosine- and Hydroxymethylcytosine-Cytosine Mismatches in a Nanopore
Authors: Wang Yong , Luan Bin-Quan , Yang Zhiyu , Zhang Xinyue , Ritzo Brandon , Gates Kent , Gu Li-Qun
Published: August 2014

Both cytosine-Ag-cytosine interactions and cytosine modifications in a DNA duplex have attracted great interest for research. Cytosine (C) modifications such as methylcytosine (mC) and hydroxymethylcytosine (hmC) are associated with tumorigenesis. However, a method for directly discriminating C, mC and hmC bases without labeling, modification and amplification is still missing. Additionally, the nature of coordination of Ag+ with cytosine-cytosine (C-C) mismatches is not clearly understood. Utilizing the alpha-hemolysin nanopore, we show that in the presence of Ag+, duplex stability is most increased for the cytosine-cytosine (C-C) pair, followed by the cytosine-methylcytosine (C-mC) pair and the cytosine-hydroxymethylcytosine (C-hmC) pair, which has no observable Ag+ induced stabilization. Molecular dynamics simulations reveal that the hydrogen-bond-mediated paring of a C-C mismatch results in a binding site for Ag+. Cytosine modifications (such as mC and hmC) disrupted the hydrogen bond, resulting in disruption of the Ag+ binding site. Our experimental method provides a novel platform to study the metal ion-DNA interactions and could also serve as a direct detection method for nucleobase modifications.
Measuring bacterial adaptation dynamics at the single-cell level using a microfluidic chemostat and time-lapse fluorescence microscopy
Authors: Long Zhicheng , Olliver Anne , Brambilla Elisa , Sclavi Bianca , Lagomarsino Marco Cosentino , Dorfman Kevin D.
Published: August 2014

We grewE. coliin a microfluidic chemostat and monitored the dynamics of cell dimensions and reporter GFP expression in individual cells during nutritional upshift or downshift.
Rapid and sensitive detection of abamectin in edible oils by solid phase extraction combined with ultra-high-pressure liquid chromatography-tandem mass spectrometry
Authors: Wu Jian-Yuan , Zhang Yu , Peng Xi-Tian , Yu Qiong-Wei , Feng Yu-Qi
Published: August 2014

Determination of abamectin in edible oils has been developed and validated by UPLC-MS/MS coupled with a novel HAS-based SPE method.