bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design of tunable bandpass filter with an improved J‐inverter
Authors: Nam Hee , Lee Myeong‐Gil , Park Joung‐Geun , Lee Byungje , Choi Jin‐Joo , Kim Jin‐Young , Lee Jong‐Chul 
Published: February 2013

AbstractIn this paper, a novel tunable bandpass filter with an improved J‐inverter is suggested. In this resonator, as the loading capacitance is increased, the resonant frequency is decreased. Also, the phase of the admittance inverter has characteristics that are variable by series capacitors and parallel varactor diodes. The electrical length of the inverter always maintains 90° at a given physical length of the inverter, which should be changed for different operating frequencies. This new bandpass filter has a tuning range of 1.8 GHz ∼ 2.45 GHz and an insertion loss of less than 2.5 dB. Also, the bandwidth is almost constant within the tuning range. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:852–855, 2013; View this article online at wileyonlinelibrary.com. DOI: 10.1002/mop.27467
In vivo investigation of restricted diffusion in the human brain with optimized oscillating diffusion gradient encoding
Authors: Van Anh T. , Holdsworth Samantha J. , Bammer Roland 
Published: February 2013

PurposePrevious studies in phantoms and animals using animal MR systems have shown promising results in using oscillating gradient spin echo (OGSE) diffusion acquisition to depict microstructure information. The OGSE approach has also been shown to be a sensitive biomarker of tumor treatment response and white matter‐related diseases. Translating these studies to a human MR scanner faces multiple challenges due to the much weaker gradient system. The goals of this study are to optimize the OGSE acquisition for a human MR system and investigate its applicability in the in vivo human brain.MethodsAn analytical analysis of the OGSE modulation spectrum was provided. Based on this analysis and thorough simulation experiments, the OGSE acquisition was optimized in terms of diffusion waveform shape, waveform timing, and sequence timing—to achieve higher diffusion sensitivity and better sampling of the diffusion spectrum.ResultsThe trapezoid‐cosine waveform was found to be the optimal OGSE waveform. At the three employed peak encoding frequencies of 18 Hz, 44 Hz, and 63 Hz, the waveform polarity for the least blurry sampling of the diffusion spectrum was 90+/180−, 90+/180+, and 90+/180+, respectively. For the highest diffusion‐to‐noise ratio at 63 Hz, the b‐value was 200 s/mm2 and the echo time was 116 ms. Using the optimized sequence, a frequency dependence of the measured apparent diffusion coefficients was observed in white matter‐dominant regions such as the corpus callosum.ConclusionThe obtained results demonstrate, for the first time, the potential of using an OGSE acquisition for investigating microstructure information on a human MR system. Magn Reson Med 71:83–94, 2014. © 2012 Wiley Periodicals, Inc.
Functional MRI in human subjects with gradient‐echo and spin‐echo EPI at 9.4 T
Authors: Budde Juliane , Shajan G. , Zaitsev Maxim , Scheffler Klaus , Pohmann Rolf 
Published: February 2013

PurposeThe increased signal‐to‐noise ratio and blood oxygen level dependent signal at ultra‐high field can only help to boost the resolution in functional MRI studies if the spatial specificity of the activation signal is improved. At a field strength of 9.4 T, both gradient‐echo and spin‐echo based echo‐planar imaging were implemented and applied to investigate the specificity of human functional MRI. A finger tapping paradigm was used to acquire functional MRI data with scan parameters similar to standard neuroscientific applications.MethodsSpatial resolution, echo, and readout times were varied to determine their influence on the distribution of the blood oxygen level dependent signal. High‐resolution co‐localized images were used to classify the signal according to its origin in veins or tissue.ResultsHigh‐quality activation maps were obtained with both sequences. Signal contributions from tissue were found to be smaller or slightly larger than from veins. Gradient‐echo echo‐planar imaging yielded lower ratios of micro‐/macro‐vascular signals of around 0.6 than spin‐echo based functional MRI, where this ratio varied between 0.75 and 1.02, with higher values for larger echo and shorter readout time.ConclusionThis study demonstrates the feasibility of human functional MRI at 9.4 T with high spatial specificity. Although venous contributions could not be entirely suppressed, venous effects in spin‐echo echo‐planar imaging are significantly reduced compared with gradient‐echo echo‐planar imaging. Magn Reson Med 71:209–218, 2014. © 2013 Wiley Periodicals, Inc.
Effects of combined heat and light soaking on device performance of Cu(In,Ga)Se2 solar cells with ZnS(O,OH) buffer layer
Authors: Kobayashi Taizo , Yamaguchi Hiroshi , Nakada Tokio 
Published: February 2013

ABSTRACTThe impacts of air annealing, light soaking (LS), and heat–light soaking (HLS) on cell performances were investigated for ZnS(O,OH)/Cu(In,Ga)Se2 (CIGS) thin‐film solar cells. It was found that the HLS post‐treatment, a combination of LS and air annealing at 130 °C, is the most effective process for improving the cell performances of ZnS(O,OH)/CIGS devices. The best solar cell yielded a total area efficiency of 18.4% after the HLS post‐treatment. X‐ray photoelectron spectroscopy showed that the improved cell performance was attributable to the decreased S/(S + O) atomic ratio, not only in the surface region but also the interface region between the ZnS(O,OH) and CIGS layers, implying the shift to an adequate conduction‐band offset at the ZnS(O,OH)/CIGS interface. Copyright © 2013 John Wiley & Sons, Ltd.
Extracting knowledge from protein structure geometry
Authors: Røgen Peter , Koehl Patrice 
Published: February 2013

AbstractProtein structure prediction techniques proceed in two steps, namely the generation of many structural models for the protein of interest, followed by an evaluation of all these models to identify those that are native‐like. In theory, the second step is easy, as native structures correspond to minima of their free energy surfaces. It is well known however that the situation is more complicated as the current force fields used for molecular simulations fail to recognize native states from misfolded structures. In an attempt to solve this problem, we follow an alternate approach and derive a new potential from geometric knowledge extracted from native and misfolded conformers of protein structures. This new potential, Metric Protein Potential (MPP), has two main features that are key to its success. Firstly, it is composite in that it includes local and nonlocal geometric information on proteins. At the short range level, it captures and quantifies the mapping between the sequences and structures of short (7‐mer) fragments of protein backbones through the introduction of a new local energy term. The local energy term is then augmented with a nonlocal residue‐based pairwise potential, and a solvent potential. Secondly, it is optimized to yield a maximized correlation between the energy of a structural model and its root mean square (RMS) to the native structure of the corresponding protein. We have shown that MPP yields high correlation values between RMS and energy and that it is able to retrieve the native structure of a protein from a set of high‐resolution decoys. Proteins 2013. © 2012 Wiley Periodicals, Inc.
Photoconductivity and optical properties of silicon coated by thin TiO2 film in situ doped by Au nanoparticles
Authors: Töfflinger Jan Amaru , Pedrueza Esteban , Chirvony Vladimir , Leendertz Caspar , García‐Calzada Raúl , Abargues Rafael , Gref Orman , Roczen Maurizio , Korte Lars , Martínez‐Pastor Juan P. , Rech Bernd 
Published: February 2013

AbstractLight trapping enhancement by plasmonic‐active metal nanoparticles (NPs) is believed to be a promising approach to increase silicon‐based solar cell efficiency. Therefore, we investigated TiO2 films in situ doped by Au NPs (TiO2:AuNPs) deposited by spin coating on a silicon substrate. Photoconductivity and optical properties of the TiO2:AuNPs/Si structures were studied in comparison with those of TiO2/Si reference samples. We found that an introduction of the 40–50 nm diameter AuNPs into the antireflective TiO2 layer deteriorates the antireflection properties and decreases the external yield of photogeneration of charge carriers. This is due to an increase of the layer reflection in the red‐IR part of the spectrum, and due to the parasitic absorption of light by AuNPs in the blue‐green part. Charge carrier recombination effect at the TiO2:AuNPs/Si interface is also found to decrease the external yield. We conclude that the TiO2:AuNPs layers could potentially be applied on the rear but not on the front side of Si solar cells.
Photoluminescence decay time studies on ZnS in cubic and hexagonal phase and its mechanico‐chemical interaction with polyaniline
Authors: Scocioreanu Malvina , Mihut Lucian , Baibarac Mihaela , Baltog Ioan 
Published: February 2013

AbstractWe report new photoluminescence (PL) data generated by pulsed optical excitation on the composites achieved by a mechanico‐chemical reaction between ZnS in the cubic (c) and wurtzite (w) phases and polyaniline‐emeraldine base (PANI‐EB). Under continuous and pulsed optical excitation, powders of the (w)ZnS and (w)ZnS/PANI‐EB composites display PL with different spectral compositions. Contrary to expectations, the (c)ZnS and the (c)ZnS/PANI‐EB composite displayed weak PL and decay time in the range of nanoseconds. This results from the great involvement of the surface states in nanometric powders which creates efficient channels for the non‐radiative recombination of the carriers. magnified imagePL spectra of (w)ZnS/PANI‐EB under continous (a) and pulsed optical excitation (b).
Collective states of two‐dimensional electron–hole system under the influence of Rashba spin–orbit coupling
Authors: Dumanov E. V. , Gherciu L. E. 
Published: February 2013

AbstractThis study is concerned with a two‐dimensional (2D) electron–hole (e–h) system in a strong perpendicular magnetic field with special attention devoted to the Rashba spin–orbit coupling (RSOC). The influence of this interaction on the chemical potential of the Bose–Einstein condensed magnetoexcitons and on the ground‐state energy of the metallic‐type electron–hole liquid (EHL) is investigated in the Hartree–Fock approximation (HFA). The magnetoexciton ground‐state energy, and the energy of the single‐particle elementary excitations were obtained. We demonstrated that chemical potential is a monotonic function versus the value of the filling factor with negative compressibility, which leads to instability of the Bose–Einstein condensate of magnetoexcitons. The energy per one e–h pair inside the electron–hole droplets (EHD) is found to be situated on the energy scale lower than the value of the chemical potential of the Bose–Einstein condensed magnetoexcitons with wave vector ${\bf k} = 0$ calculated in the HFA.
Biodegradation of Single‐Walled Carbon Nanotubes by Eosinophil Peroxidase
Authors: Andón Fernando T. , Kapralov Alexandr A. , Yanamala Naveena , Feng Weihong , Baygan Arjang , Chambers Benedict J. , Hultenby Kjell , Ye Fei , Toprak Muhammet S. , Brandner Birgit D. , Fornara Andrea , Klein‐Seetharaman Judith , Kotchey Gregg P. , Star Alexander , Shvedova Anna A. , Fadeel Bengt , Kagan Valerian E. 
Published: February 2013

AbstractEosinophil peroxidase (EPO) is one of the major oxidant‐producing enzymes during inflammatory states in the human lung. The degradation of single‐walled carbon nanotubes (SWCNTs) upon incubation with human EPO and H2O2 is reported. Biodegradation of SWCNTs is higher in the presence of NaBr, but neither EPO alone nor H2O2 alone caused the degradation of nanotubes. Molecular modeling reveals two binding sites for SWCNTs on EPO, one located at the proximal side (same side as the catalytic site) and the other on the distal side of EPO. The oxidized groups on SWCNTs in both cases are stabilized by electrostatic interactions with positively charged residues. Biodegradation of SWCNTs can also be executed in an ex vivo culture system using primary murine eosinophils stimulated to undergo degranulation. Biodegradation is proven by a range of methods including transmission electron microscopy, UV‐visible‐NIR spectroscopy, Raman spectroscopy, and confocal Raman imaging. Thus, human EPO (in vitro) and ex vivo activated eosinophils mediate biodegradation of SWCNTs: an observation that is relevant to pulmonary responses to these materials.
Gold Nanoparticle–Protein Agglomerates as Versatile Nanocarriers for Drug Delivery
Authors: Khandelia Rumi , Jaiswal Amit , Ghosh Siddhartha Sankar , Chattopadhyay Arun 
Published: February 2013

AbstractThe fabrication of a versatile nanocarrier based on agglomerated structures of gold nanoparticle (Au NP)–lysozyme (Lyz) in aqueous medium is reported. The carriers exhibit efficient loading capacities for both hydrophilic (doxorubicin) and hydrophobic (pyrene) molecules. The nanocarriers are finally coated with an albumin layer to render them stable and also facilitate their uptake by cancer cells. The interaction between agglomerated structures and the payloads is non‐covalent. Cell viability assay in vitro showed that the nanocarriers by themselves are non‐cytotoxic, whereas the doxorubicin‐loaded ones are cytotoxic, with efficiencies higher than that of the free drug. Transmission electron microscopy and fluorescence microscopy along with flow cytometry analysis confirm the uptake of the drug‐loaded nanocarriers by a human cervical cancer HeLa cell line. Field‐emission scanning electron microscopy reveals the formation of apoptotic bodies leading to cell death, confirming the release of the payloads from the nanocarriers into the cell. Overall, the findings suggest the fabrication of novel Au NP–protein agglomerate‐based nanocarriers with efficient drug‐loading and ‐releasing capabilities, enabling them to act as multimodal drug‐delivery vehicles.
Entropy Metrics for System Identification and Analysis
Authors: Simpson Joseph J. , Simpson Mary J. 
Published: February 2013

ABSTRACTWhole system metrics are valuable tools for use in systems science and engineering. Entropy metrics are defined, developed, and demonstrated in this paper. Based on classical systems engineering methods and practices, these entropy metrics indicate the degree of order/disorder in any given system. A physical‐entropy based metric and an information‐based entropy metric are aligned with the two primary components of a system: objects and relationships. The physical‐entropy based metric is called a relational score, and the information‐based metric is called an object score. A subsystem score, based on the relational score and object score, is also developed and presented in this paper. A well‐defined process, using these metrics, is used to evaluate the reduction of entropy and complexity associated with any specific system. The metrics and processes developed in this work have a prose component, a graphic component, and a mathematical component. These three components are aligned with the systems science techniques developed by John N. Warfield.
Game‐Based Curricula in Biology Classes: Differential Effects Among Varying Academic Levels
Authors: Sadler Troy D. , Romine William L. , Stuart Parker E. , Merle‐Johnson Dominike 
Published: February 2013

AbstractVideo games have become a popular medium in our society, and recent scholarship suggests that games can support substantial learning. This study stems from a project in which we created a video game enabling students to use biotechnology to solve a societal problem. As students engaged in the game, they necessarily interacted with the underlying biological principles. The study focused on the extent to which students learned biology concepts in the context of a game‐based curriculum. In particular, we explored learning among high school students, stratified across different academic levels (i.e., general, honors, and advanced). We used a pre/post‐test repeated measures multiple analysis of variance (MANOVA) design and a multi‐level assessment strategy with assessments positioned at variable distances from the curriculum to illuminate the nature of student learning and the potential interactions of academic level and learning associated with the game‐based curriculum. A total of 647 students from 31 different biology classes, taught by 10 different teachers, participated in the study. Results indicated statistically and practically significant gains in student performance on both a proximal (curriculum‐aligned) test and a distal (standards‐aligned) exam of biological content knowledge. Students from classes across all three academic levels demonstrated gains with relatively large effect sizes on the proximal test. Whereas the honors and advanced students demonstrated less substantial gains on the distal exam, the general students demonstrated gains of similar effect size on both the proximal and distal assessments. These results suggest that, despite teacher concerns about the potential effectiveness of gaming to support learning among students in lower academic levels, game‐based curricula can support learning of important biological content for students of varying academic levels and may, in fact, be most beneficial for lower level students. The affordances of employing a multi‐level assessment model for the investigation of innovative curricula are discussed. © 2013 Wiley Periodicals, Inc. J Res Sci Teach 50: 479‐499, 2013
Attention maps in the brain
Authors: Somers David C. , Sheremata Summer L. 
Published: February 2013

AbstractOver 20 distinct cerebral cortical areas contain spatial map representations of the visual field. These retinotopic, or visuotopic, cortical areas occur not only in the occipital lobe but also in the parietal, temporal, and frontal lobes. The cognitive influences of visuospatial attention operate via these cortical maps and can support selection of multiple objects at the same time. In early visual cortical areas, spatial attention enhances responses of selected items and diminishes the responses to distracting items. In higher order cortex, the maps support a spatial indexing role, keeping track of the items to be attended. These maps also support visual short‐term memory (VSTM) representations. In each hemisphere, all the known maps respond selectively to stimuli presented within the contralateral visual field. However, a hemispheric asymmetry emerges when the attentional or VSTM demands of a task become significant. In the parietal lobe, the right hemisphere visuotopic maps switch from coding only contralateral visual targets to coding memory and attention targets across the entire visual field. This emergent asymmetry has important implications for understanding hemispatial neglect syndrome, and supports a dynamic network form of the representational model of neglect. WIREs Cogn Sci 2013, 4:327–340. doi: 10.1002/wcs.1230This article is categorized under:

Psychology > Attention
Neuroscience > Cognition
Core pathways controlling shoot meristem maintenance
Authors: Lee Chunghee , Clark Steven E. 
Published: February 2013

AbstractEssential to the function of shoot meristems in plants to act as sites of continuous organ and tissue formation is the ability of cells within the meristem to remain undifferentiated and proliferate indefinitely. These are characteristics of the stem cells within meristems that are critical for their growth properties. Stem cells are found in tight association with the stem cell niche—those cells that signal to maintain stem cells. Shoot meristems are unique among stem cell systems in that the stem cell niche is a constantly changing population of recent daughter stem cells. Recent progress from Arabidopsis and other systems have uncovered a large number of genes with defined roles in meristem structure and maintenance. This review will focus on well‐studied pathways that represent signaling between the stem cells and the niche, that prevent ectopic differentiation of stem cells, that regulate the chromatin status of stem cell factors, and that reveal intersection of hormone signaling and meristem maintenance. WIREs Dev Biol 2013, 2:671–684. doi: 10.1002/wdev.110This article is categorized under:

Gene Expression and Transcriptional Hierarchies > Cellular Differentiation
Plant Development > Vegetative Development
Plant Development > Inflorescence, Flower, and Fruit Development
Lymph Node Ratio May Be Supplementary to TNM Nodal Classification in Node‐positive Breast Carcinoma Based on the Results of 2,151 Patients
Authors: Duraker Nüvit , Batı Bakir , Çaynak Zeynep Civelek , Demir Davut 
Published: February 2013

AbstractBackgroundThe aim of the present study was to determine how lymph node ratio (LNR; the ratio of the number of metastatic lymph nodes to the number of removed lymph nodes) can supplement the TNM nodal classification in breast carcinoma.MethodsWe retrospectively reviewed the file records of 2,151 patients.ResultsLymph node ratio‐based low‐ (LNR ≤ 0.20), intermediate‐ (LNR 0.21–0.65), and high‐risk (LNR > 0.65) patient groups had significantly different disease‐free survival (DFS) (P < 0.001). The DFS of patients with N1, N2, and N3 disease was significantly different (P < 0.001). When LNR and TNM nodal groupings were included together in the Cox analysis, both groupings had independent prognostic significance (P < 0.001 and P < 0.001, respectively). The most significant LNR threshold value separating patients in low‐risk and high‐risk groups in terms of disease recurrence was 0.20 for N1 disease (P < 0.001), 0.35 for N2 disease (P < 0.001), and 0.90 for N3 disease (P < 0.001).ConclusionsLymph node ratio and TNM nodal groupings show no superiority over each other in categorizing patients with node‐positive breast carcinoma into prognostic groups of low‐, intermediate‐, and high‐risk. However, LNR grouping may supplement TNM nodal classification by categorizing patients within each TNM nodal group into low‐risk and high‐risk groups with significantly different survival.