bluuebunny/crossref_metadata_2025 huggingface dataset:
EDGE coupled variable microfluidic directional coupler
Authors: Murray Casey , Franklin Rhonda R.
Published: February 2013

A microstrip directional coupler with a microfluidic superstrate in the coupling gap is investigated.In the microfluidic channel, relative dielectric constant values ranging from εr = 81 to εr = 1, deionized water and air are studied, respectively. The tuning range of the coupler is evaluated experimentally and compared to its full‐wave simulation. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:756–758, 2013; View this article online at wileyonlinelibrary.com. DOI: 10.1002/mop.27436
Design and development of U‐notched corner truncated square microstrip antenna for X to Ku band operation
Authors: Singh Kishan , Mulgi S.N.
Published: February 2013

This article reports the design and development of horizontally U‐notched corner truncated square microstrip antenna (UCSQMA) for dual‐band operation. If one more U‐notch is placed perpendicular to the horizontal U‐notches on the radiating patch, the antenna resonates for triple band of frequencies. Further, if H‐slot is placed on the ground plane of this antenna, the antenna operates for single band and gives a maximum impedance bandwidth of 82.68% covering X to Ku bands without changing the nature of broadside radiation characteristics. The proposed antenna may find applications for the systems operating in the frequency range of 7.53 GHz to 18 GHz. Details of antenna design are described and experimental results are discussed. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:719–723, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27438
Applying line‐series‐shunt calibration to one‐tier on‐wafer device de‐embedding up to millimeter waves
Authors: Huang Chien‐Chang , Chen Yu‐Chuan
Published: February 2013

In this article, a one‐tier on‐wafer device de‐embedding methodology up to millimeter wave regions is presented by using the line‐series‐shunt calibration technique. All the calibration and de‐embedding processes are accomplished without the needs of impedance‐standard‐substrate (ISS), which defines the reference impedance in the conventional on‐wafer measurements. Three on‐chip standards, namely a section of transmission line (TL), a series resistor, and a shunt resistor, are utilized to perform the calibration where the characteristics of the standards need not to be known in advance and can be evaluated through the self‐calibration procedure. The proposed method is examined by the GaAs 0.15 μm pseudomorphic high electron mobility transistor (pHEMT) device in the measured frequencies from 2 GHz to 90 GHz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:744–747, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27445
Design of a multi‐band asymmetric patch antennal for wireless applications
Authors: Malekpoor Hossein , Jam Shahrokh
Published: February 2013

A novel design for probe‐fed compact multiband microstrip patch antenna for wireless applications is presented in this article. The antenna is achieved by cutting the different slots' length on the patch and using unequal resonance arms. By adjusting unequal arms, various resonant frequencies are obtained. Also, this antenna presents resonance tuning ability within impedance bands by varying the length of the slots. The proposed antenna is designed and fabricated for operating at 3.66 GHz, 5.3 GHz, 5.8 GHz, and 7.03 GHz. The size of patch is 0.314λL × 0.342λL at its lower operating frequency. In addition, parametric studies are performed by investigating the effects of some key parameters on obtaining an optimal design of the proposed antenna. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:730–734, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27449
A novel terahertz multiband resonator based on tu‐shaped microstructure
Authors: Wang Wen‐Tao , Liu Jian‐Jun , Hong Zhi
Published: February 2013

We have designed and fabricated a terahertz multiband resonator based on TU‐shaped metallic microstructure on polyimide substrate. The performance of the fabricated device was examined by using a terahertz time‐domain spectroscopy system. The experimental results show three distinct resonant peaks at 0.37, 0.73 and 0.96 THz, which are in good agreement with the finite‐difference time‐domain (FDTD) simulation. The multiband resonators have great potential applications in the fields such as terahertz imaging and biosensors. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:857–859, 2013; View this article online at wileyonlinelibrary.com. DOI: 10.1002/mop.27457
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

In 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

Purpose

Previous 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.

Methods

An 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.

Results

The 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.

Conclusion

The 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

Purpose

The 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.

Methods

Spatial 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.

Results

High‐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.

Conclusion

This 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

The 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.
Managing Risks in Complex Projects
Authors: Thamhain Hans
Published: February 2013

Dealing effectively with risks in complex projects is difficult and requires management interventions that go beyond simple analytical approaches. This is one finding of a major field study into risk management practices and business processes of 35 major product developments in 17 high-technology companies. Almost one-half of the contingencies that occur are not being detected before they impact project performance. Yet, the risk-impact model presented in this article shows that risk does not affect all projects equally but depends on the effectiveness of collective managerial actions dealing with specific contingencies. The results of this study discuss why some organizations are more successful in detecting risks early in the project life cycle, and in decoupling risk factors from work processes before they impact project performance. The field data suggest that effective project risk management involves an intricately linked set of variables, related to work process, organizational environment, and people. Some of the best success scenarios point to the critical importance of recognizing and dealing with risks early in their development. This requires broad involvement and collaboration across all segments of the project team and its environment, and sophisticated methods for assessing feasibilities and usability early and frequently during the project life cycle. Specific managerial actions, organizational conditions, and work processes are suggested for fostering a project environment most conducive to effective cross-functional communication and collaboration among all stakeholders, a condition important to early risk detection and effective risk management in complex project situations.
Extracting knowledge from protein structure geometry
Authors: Røgen Peter , Koehl Patrice
Published: February 2013

Protein 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

Light 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

We 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 image

PL 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

This 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.
Antiplatelet Activity of a Novel Formula Composed of Malic Acid, Succinic Acid and Citric Acid from Cornus officinalis Fruit
Authors: Zhang Qi‐Chun , Zhao Yue , Bian Hui‐Min
Published: February 2013

The present study investigated the antiplatelet activity of a novel formula composed by malic acid, succinic acid and citric acid with a ratio of 3:2:2. The IC50 and inhibition of platelet aggregation induced by various agonists as well as platelet adhesion were evaluated in vitro. Of note, the IC50 for the formula inhibiting adenosine diphosphate (ADP)‐induced platelet aggregation was 0.185 mg/mL. Meanwhile, the formula showed more potent inhibitory effect on platelet aggregation induced by ADP and thrombin than the single component at same concentration (0.37 mg/mL). Moreover, the formula could prevent platelet adhesion significantly without influence on platelet viability. Copyright © 2013 John Wiley & Sons, Ltd.
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

Eosinophil 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

The 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

Whole 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

Video 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

Over 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.1230

This article is categorized under:

Psychology > Attention

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

Essential 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.110

This 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

Background

The 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.

Methods

We retrospectively reviewed the file records of 2,151 patients.

Results

Lymph 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).

Conclusions

Lymph 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.
Conformation‐specific crosslinking of mitochondrial complex I
Authors: Ciano Margherita , Fuszard Matthew , Heide Heinrich , Botting Catherine H. , Galkin Alexander
Published: February 2013

ND3
and
NDUFA9
physically interact by cross‐linking study (View interaction)
CACTIN is an essential nuclear protein in Arabidopsis and may be associated with the eukaryotic spliceosome
Authors: Baldwin Katherine L. , Dinh Elizabeth M. , Hart Brian M. , Masson Patrick H.
Published: February 2013

ATG7
physically interacts with
ATG12A
by two hybrid (View Interaction: 1, 2)
Prognosis for Functional Deterioration and Functional Improvement in Late Life Among Community‐Dwelling Persons
Authors: Stineman Margaret G. , Zhang Guangyu , Kurichi Jibby E. , Zhang Zi , Streim Joel E. , Pan Qiang , Xie Dawei
Published: February 2013

Objective

To examine how health‐related, socioeconomic, and environmental factors combine to influence the onset of activity of daily living (ADL) limitations or prognosis for death or further functional deterioration or improvement among elderly people.

Design

A national representative sample with 2‐year follow‐up.

Setting

Community‐dwelling people.

Participants

Included were 9447 persons (≥70 years of age) in the United States from the Second Longitudinal Study of Aging who were interviewed in 1994, 1995, or 1996.

Methods

Self‐ or proxy‐reported health conditions, ADLs expressed as 5 stages describing severity and pattern of limitations, and other baseline characteristics were obtained. A multinomial logistic regression model was used to predict stage transitions. Because of incomplete follow‐up (17.7% of baseline sample), primary analyses were determined by multiple imputation to address potential bias associated with loss to follow‐up.

Main Outcome Measurement

ADL stage transitions in 2 years (death, deteriorated, stable, and improved ADL function).

Results

In the imputed‐case analysis, the percentages for those who died, deteriorated, were stable, and improved were 12.6%, 32.7%, 48.4%, and 6.2%, respectively. Persons at a mild stage of ADL limitation were most likely to deteriorate further. Persons at advanced stages were most likely to die. Married people and high school graduates had a lower likelihood of deterioration. The risk of mortality and functional deterioration increased with age. Certain conditions, such as diabetes, were associated both with mortality and functional deterioration; other conditions, such as cancer, were associated with mortality only, and arthritis was associated only with functional deterioration.

Conclusions

Although overlap occurs, different clinical traits are associated with mortality, functional deterioration, and functional improvement. ADL stages might aid physical medicine and rehabilitation clinicians and researchers in developing and monitoring disability management strategies targeted to maintaining and enhancing self‐care among community‐dwelling older people.
The Prevalence of Fluid Associated With the Iliotibial Band in Asymptomatic Recreational Runners: An Ultrasonographic Study
Authors: Jelsing Elena J. , Finnoff Jonathan , Levy Bruce , Smith Jay
Published: February 2013

Objective

To evaluate the prevalence and distribution of fluid associated with the iliotibial band (ITB) in asymptomatic recreational runners.

Design

Prospective cohort study.

Setting

Sports medicine center at a tertiary medical center.

Patients

Five male and 15 female asymptomatic recreational runners (10‐30 miles per week) ages 18‐40 years.

Methods

Participants were examined with the use of ultrasonography to assess for the presence of fluid at the level of the lateral femoral epicondyle and determine its relationship to the ITB at 0 and 30° of knee flexion in both supine (non–weight‐bearing) and standing (weight‐bearing) positions.

Results

Fluid was associated with the ITB in 100% of asymptomatic recreational runners and was bilateral in 90%. When examined in full extension with the subject supine, fluid was seen in 67.5% of knees (n = 40) compared with 95% of the knees when standing. When examined in 30° of flexion, the presence of fluid decreased to 30% when supine and 22.5% when standing. With the knee in full extension in a supine/standing position, fluid was located anterior and deep 70%/74% of the time and was anterior only 11%/0% of the time. With the knee flexed to 30° in a supine/standing position, fluid was located anterior and deep 50%/33% of the time and anterior only 33%/67% of the time.

Conclusion

The prevalence of fluid associated with the ITB varied with body and knee position, was most common in the standing position with the knee extended, and was generally located anterior or anterior and deep to the ITB. The clinical significance of our findings are 2‐fold: (1) body position should be considered when searching for fluid in the vicinity of the ITB, and (2) clinicians and imagers should exercise caution when interpreting the clinical significance of fluid associated with the ITB during ultrasonographic evaluation of runners with lateral knee pain.
Initial growth of a disturbance in a boundary layer influenced by a circular cylinder wake
Authors: He Guosheng , Wang Jinjun , Pan Chong
Published: February 2013

The initial growth of a disturbance induced by a near-wall circular cylinder in a flat-plate boundary layer is experimentally investigated using both particle image velocimetry and hydrogen bubble visualization techniques. The secondary spanwise vortices appear in the near-wall region as a direct response to the outside passing wake vortices, consistent with previous studies on similar models (Pan et al., J. Fluid Mech., vol. 603, 2008, pp. 367–389; Mandal & Dey, J. Fluid Mech., vol. 684, 2011, pp. 60–84). The streamwise variation of the total disturbance energy within the boundary layer shows a two-stage growth, which characterizes the initial transition process: the first exponential growth stage, followed by a region with slower growth rate. It is revealed that these two stages of growth are related to the formation and the destabilization of the secondary vortex in the near-wall region. The technique of dynamic mode decomposition is used to decompose the total disturbance into temporally orthogonalized modes, and it shows that the first growth stage largely results from the increased disturbance at the same frequency as that of the wake vortex shedding, while the second growth stage comprises the disturbance growth in a number of frequencies, especially the lower ones.
Stability of a liquid ring on a substrate
Authors: González Alejandro G. , Diez Javier A. , Kondic Lou
Published: February 2013

We study the stability of a viscous incompressible fluid ring on a partially wetting substrate within the framework of long-wave theory. We discuss the conditions under which a static equilibrium of the ring is possible in the presence of contact angle hysteresis. A linear stability analysis (LSA) of this equilibrium solution is carried out by using a slip model to account for the contact line divergence. The LSA provides specific predictions regarding the evolution of unstable modes. In order to describe the evolution of the ring for longer times, a quasi-static approximation is implemented. This approach assumes a quasi-static evolution and takes into account the concomitant variation of the instantaneous growth rates of the modes responsible for either collapse of the ring into a single central drop or breakup into a number of droplets along the ring periphery. We compare the results of the LSA and the quasi-static model approach with those obtained from nonlinear numerical simulations using a complementary disjoining pressure model. We find remarkably good agreement between the predictions of the two models regarding the expected number of drops forming during the breakup process.
Skin friction on a moving wall and its implications for swimming animals
Authors: Ehrenstein Uwe , Eloy Christophe
Published: February 2013

Estimating the energetic costs of undulatory swimming is important for biologists and engineers alike. To calculate these costs it is crucial to evaluate the drag forces originating from skin friction. This topic has been controversial for decades, some claiming that animals use ingenious mechanisms to reduce the drag and others hypothesizing that undulatory swimming motions induce a drag increase because of the compression of the boundary layers. In this paper, we examine this latter hypothesis, known as the ‘Bone–Lighthill boundary-layer thinning hypothesis’, by analysing the skin friction in different model problems. First, we study analytically the longitudinal drag on a yawed cylinder in a uniform flow by using the approximation of the momentum equations in the laminar boundary layers. This allows us to demonstrate and generalize a result first observed semi-empirically by G.I. Taylor in the 1950s: the longitudinal drag scales as the square root of the normal velocity component. This scaling arises because the fluid particles accelerate as they move around the cylinder. Next we propose an analogue two-dimensional problem where the same scaling law is recovered by artificially accelerating the flow in a channel of finite height. This two-dimensional problem is then simulated numerically to assess the robustness of the analytical results when inhomogeneities and unsteadiness are present. It is shown that spatial or temporal changes in the normal velocity usually tend to increase the skin friction compared with the ideal steady case. Finally, these results are discussed in the context of swimming energetics. We find that the undulatory motions of swimming animals increase their skin friction drag by an amount that closely depends on the geometry and the motion. For the model problem considered in this paper the increase is of the order of 20 %.
Contact lines with a contact angle
Authors: Benilov E. S. , Vynnycky M.
Published: February 2013

This work builds on the foundation laid by Benney & Timson (Stud. Appl. Maths, vol. 63, 1980, pp. 93–98), who examined the flow near a contact line and showed that, if the contact angle is $18{0}^{\circ } $, the usual contact-line singularity does not arise. Their local analysis, however, does not allow one to determine the velocity of the contact line and their expression for the shape of the free boundary involves undetermined constants. The present paper considers two-dimensional Couette flows with a free boundary, for which the local analysis of Benney & Timson can be complemented by an analysis of the global flow (provided that the slope of the free boundary is small, so the lubrication approximation can be used). We show that the undetermined constants in the solution of Benney & Timson can all be fixed by matching the local and global solutions. The latter also determines the contact line’s velocity, which we compute among other characteristics of the global flow. The asymptotic model derived is used to examine steady and evolving Couette flows with a free boundary. It is shown that the latter involve brief intermittent periods of rapid acceleration of contact lines.
Self-similar mean dynamics in turbulent wall flows
Authors: Klewicki J. C.
Published: February 2013

This study investigates how and why dynamical self-similarities emerge with increasing Reynolds number within the canonical wall flows beyond the transitional regime. An overarching aim is to advance a mechanistically coherent description of turbulent wall-flow dynamics that is mathematically tractable and grounded in the mean dynamical equations. As revealed by the analysis of Fife, Klewicki & Wei (J. Discrete Continuous Dyn. Syst.A, vol. 24, 2009, pp. 781–807), the equations that respectively describe the mean dynamics of turbulent channel, pipe and boundary layer flows formally admit invariant forms. These expose an underlying self-similar structure. In all cases, two kinds of dynamical self-similarity are shown to exist on an internal domain that, for all Reynolds numbers, extends from$O(\nu / {u}_{\tau } )$to$O(\delta )$, where$\nu $is the kinematic viscosity,${u}_{\tau } $is the friction velocity and$\delta $is the half-channel height, pipe radius, or boundary layer thickness. The simpler of the two self-similarities is operative on a large outer portion of the relevant domain. This self-similarity leads to an explicit analytical closure of the mean momentum equation. This self-similarity also underlies the emergence of a logarithmic mean velocity profile. A more complicated kind a self-similarity emerges asymptotically over a smaller domain closer to the wall. The simpler self-similarity allows the mean dynamical equation to be written as a closed system of nonlinear ordinary differential equations that, like the similarity solution for the laminar flat-plate boundary layer, can be numerically integrated. The resulting similarity solutions are demonstrated to exhibit nearly exact agreement with direct numerical simulations over the solution domain specified by the theory. At the Reynolds numbers investigated, the outer similarity solution is shown to be operative over a domain that encompasses${\sim }40\hspace{0.167em} \% $of the overall width of the flow. Other properties predicted by the theory are also shown to be well supported by existing data.
A simple constitutive model for predicting the pressure histories developed behind rigid porous media impinged by shock waves
Authors: Ram O. , Sadot O.
Published: February 2013

Shock wave attenuation by means of rigid porous media is often applied when protective structures are dealt with. The passage of a shock wave through a layer of porous medium is accompanied by diffractions and viscous effects that attenuate and weaken the transmitted shock, thus reducing the load that develops on the target wall that is placed behind the protective layer. In the present study, the parameters governing the pressure build-up on the target wall are experimentally investigated using a shock tube facility. Different porous samples are impinged by normal shock waves of various strengths and the subsequent pressure histories that are developed on the target wall are recorded. In addition, different standoff distances from the target wall are investigated. Assuming that the flow through the porous medium is close to being isentropic enabled us to develop a general constitutive model for predicting the pressure history developed on the target wall. This model can be applied to predict the pressure build-up on the target wall for any pressure history that is imposed on the front face of the porous sample without the need to conduct numerous experiments. Results obtained by other investigators are found to be in very good agreement with the predictions of the presently developed constitutive model.
Wall effects on pressure fluctuations in turbulent channel flow
Authors: Gerolymos G. A. , Sénéchal D. , Vallet I.
Published: February 2013

The purpose of the present paper is to study the influence of wall echo on pressure fluctuations${p}^{\prime } $, and on statistical correlations containing${p}^{\prime } $, namely, redistribution${\phi }_{ij} $, pressure diffusion${ d}_{ij}^{(p)} $and velocity pressure-gradient${\Pi }_{ij} $. We extend the usual analysis of turbulent correlations containing pressure fluctuations in wall-bounded direct numerical simulations (Kim,J. Fluid Mech., vol. 205, 1989, pp. 421–451), separating${p}^{\prime } $not only into rapid${ p}_{(r)}^{\prime } $and slow${ p}_{(s)}^{\prime } $parts (Chou,Q. Appl. Maths, vol. 3, 1945, pp. 38–54), but also further into volume (${ p}_{(r; \mathfrak{V})}^{\prime } $and${ p}_{(s; \mathfrak{V})}^{\prime } $) and surface (wall echo,${ p}_{(r; w)}^{\prime } $and${ p}_{(s; w)}^{\prime } $) terms. An algorithm, based on a Green’s function approach, is developed to compute the above splittings for various correlations containing pressure fluctuations (redistribution, pressure diffusion, velocity pressure-gradient), in fully developed turbulent plane channel flow. This exact analysis confirms previous results based on a method-of-images approximation (Manceau, Wang & Laurence,J. Fluid Mech., vol. 438, 2001, pp. 307–338) showing that, at the wall,${ p}_{(\mathfrak{V})}^{\prime } $and${ p}_{(w)}^{\prime } $are usually of the same sign and approximately equal. The above results are then used to study the contribution of each mechanism to the pressure correlations in low-Reynolds-number plane channel flow, and to discuss standard second-moment-closure modelling practices.