bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fluorescence Study of Chiral β‐Ketoiminate‐Based Newly Synthesized Boron Hybrid Polymers
Authors: Jiang Xiaoxiang , Liu Xunhua , Jiang Yuliang , Quan Yiwu , Cheng Yixiang , Zhu Chengjian 
Published: January 2014

Two novel chiral β‐ketoiminate‐based boron hybrid polymers, P‐1 and P‐2, are synthesized from a chiral β‐ketoiminate‐based boron hybrid complex (M‐1), with 1,4‐dioctyl‐2,5‐diethynyl­benzene (M‐2) and 3,6‐diethynyl‐9‐octyl‐9H‐carbazole (M‐3), respectively, via a Pd‐catalyzed Sonogashira coupling reaction. The resulting polymers P‐1 and P‐2 show strong fluorescence emission centered at 525 nm and 534 nm with large Stokes’ shifts and high quantum yields. Most importantly, compared with the circularly polarized luminescence (CPL) dissymmetry factor (glum = +0.042) of chiral small model molecules, P‐1 and P‐2 can exhibit a large glum as high as +0.105 and +0.349 in CH2Cl2 solution, which can be attributed to the amplification effect of CPL arising from the conjugated polymer structure.
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Developing Sub‐Nanofibers in Electrospun Nylon‐6 Web by Controlling the Parameters of the Process
Authors: Rahmani H. , Karimi M. 
Published: January 2014

SummaryThe aim of the present work is to subject the polyelectrolyte solutions of nylon‐6 in formic acid undergoes an electrospinning process. To form sub‐nanofibers (<50 nm in diameter) within the electrospun nanofibers mats, polymer concentration, applied voltage, solution temperature and environmental condition were chosen as variables. Scanning electron microscope was used to probe the presence of sub‐nanofibers into the electrospun mat. To appear sub‐nanofibers significantly, during the process of electrospinning, an optimum condition was obtained by finding a proper concentration of solution, applied voltage and temperature of solution which were 15 wt.%, 22 kV and 25 °C, respectively.
Analysis of risk factors associated with microvascular free flap failure using a multi‐institutional database
Authors: Wong Alex K. , Joanna Nguyen T. , Peric Mirna , Shahabi Ahva , Vidar Evan N. , Hwang Brian H. , Niknam Leilabadi Solmaz , Chan Linda S. , Urata Mark M. 
Published: January 2014

BackgroundThere are numerous factors that may contribute to microvascular free flap failure. Although technical issues are dominant factors, patient and clinical characteristics are also contributory. The aim of this study was to investigate non‐technical variables associated with microsurgical free flap failure using a multi‐institutional dataset.MethodsUtilizing the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database, we identified all patients who underwent microvascular free tissue transfer from 2005 through 2009. Univariate analysis was performed to determine the association of flap failure with the following factors: age, gender, ethnicity, body mass index, intraoperative transfusion, diabetes, smoking, alcohol, American Society of Anesthesiologists classification, year of operation, operative time, number of flaps, and type of reconstruction. Factors with a significance of P < 0.2 in the univariate analysis were included in the multivariate logistic regression model to identify independent risk factors.ResultsA total of 639 patients underwent microsurgical free flap reconstruction with 778 flaps over the 4‐year study period; 139 patients had two free flaps during the same operation. The overall incidence of flap failure was 4.4% (34/778) (95% confidence interval [CI]: 3.0%, 6.2%). Operative time was identified as an independent risk factor for free flap failure. After adjusting for other factors, those whose operative time was equal to or greater than the 75th percentile (625.5 min) were twice as likely to experience flap failure (AOR 2.09; 95% CI: 1.01–4.31; P = 0.045). None of the other risk factors studied were significant contributors.ConclusionsIn this series, the overall flap loss rate of was 4.4%. Operative time was a significant independent risk factor for flap failure. © 2014 Wiley Periodicals, Inc. Microsurgery 35:6–12, 2015.
Tighter uncertainty principles for periodic signals in terms of frequency
Authors: Dang Pei 
Published: January 2014

AbstractIn this study, we propose some new uncertainty principles for periodic signals with sharper lower bounds than those in the existing ones. The improved lower bounds, in particular, are related to the frequency of the signal. Three examples are employed to demonstrate sharpness of the new uncertainty principles. Copyright © 2014 John Wiley & Sons, Ltd.
Strategies to address participant misrepresentation for eligibility in Web‐based research
Authors: Kramer Jessica , Rubin Amy , Coster Wendy , Helmuth Eric , Hermos John , Rosenbloom David , Moed Rich , Dooley Meghan , Kao Ying‐Chia , Liljenquist Kendra , Brief Deborah , Enggasser Justin , Keane Terence , Roy Monica , Lachowicz Mark 
Published: January 2014

AbstractEmerging methodological research suggests that the World Wide Web (“Web”) is an appropriate venue for survey data collection, and a promising area for delivering behavioral intervention. However, the use of the Web for research raises concerns regarding sample validity, particularly when the Web is used for recruitment and enrollment. The purpose of this paper is to describe the challenges experienced in two different Web‐based studies in which participant misrepresentation threatened sample validity: a survey study and an online intervention study. The lessons learned from these experiences generated three types of strategies researchers can use to reduce the likelihood of participant misrepresentation for eligibility in Web‐based research. Examples of procedural/design strategies, technical/software strategies and data analytic strategies are provided along with the methodological strengths and limitations of specific strategies. The discussion includes a series of considerations to guide researchers in the selection of strategies that may be most appropriate given the aims, resources and target population of their studies. Copyright © 2014 John Wiley & Sons, Ltd.
Assessing impact of differential symptom functioning on post‐traumatic stress disorder (PTSD) diagnosis
Authors: He Qiwei , Glas Cees A. W. , Veldkamp Bernard P. 
Published: January 2014

AbstractThis article explores the generalizability of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM‐IV) diagnostic criteria for post‐traumatic stress disorder (PTSD) to various subpopulations. Besides identifying the differential symptom functioning (also referred to as differential item functioning [DIF]) related to various background variables such as gender, marital status and educational level, this study emphasizes the importance of evaluating the impact of DIF on population inferences as made in health surveys and clinical trials, and on the diagnosis of individual patients. Using a sample from the National Comorbidity Study‐Replication (NCS‐R), four symptoms for gender, one symptom for marital status, and three symptoms for educational level were significantly flagged as DIF, but their impact on diagnosis was fairly small. We conclude that the DSM‐IV diagnostic criteria for PTSD do not produce substantially biased results in the investigated subpopulations, and there should be few reservations regarding their use. Further, although the impact of DIF (i.e. the influence of differential symptom functioning on diagnostic results) was found to be quite small in the current study, we recommend that diagnosticians always perform a DIF analysis of various subpopulations using the methodology presented here to ensure the diagnostic criteria is valid in their own studies. Copyright © 2014 John Wiley & Sons, Ltd.
One‐minute exercise is best for evaluation of postexercise exhaustion in myasthenia gravis
Authors: OH Shin J. , Nagai Taiichi , Kizilay Ferah , Kurt Semiha 
Published: January 2014

ABSTRACTIntroduction: To find the best exercise duration for postexercise exhaustion by decrement (PEE‐D) in myasthenia gravis (MG). Methods: In 32 tests in 32 MG patients, repetitive nerve stimulation was performed in the abductor digiti quinti muscle. The 3 Hz responses for 2 s were obtained with supramaximal stimulation at rest, and immediately after (PE0), 30 s after (PE30s), and 1, 2, 3, and 4 min after 10‐s, 30‐s, and 1‐min exercises. Results: Compared with the decrement at rest, a significantly greater decrement was found at PE2m and PE3m after 30‐s exercise, and at PE2m, PE3m, and PE4m after 1‐min exercise. In 11 patients who showed a decremental response only with exercise, PEE‐D was observed in 5 after 30‐s exercise and in 8 after 1‐min exercise. Conclusions: One‐minute exercise is best for evaluation of PEE‐D in MG. Muscle Nerve 50: 413–416, 2014
Effect of caffeine ingestion on torque and muscle activity during resistance exercise in men
Authors: Duncan Michael J. , Thake Charles D. , Downs Philip J. 
Published: January 2014

ABSTRACTIntroduction: We examined the effect of caffeine ingestion on muscle torque production and muscle activity at different contraction speeds in trained men. Methods: 10 men (mean age ± SD = 22 ± 1.1 years) volunteered to participate. A double‐blind, randomized cross‐over design was used. Sixty minutes postingestion of caffeine (6 mg kg−1) or placebo, participants completed 6 repetitions of isokientic knee extension at 3 angular velocities (30°s−1, 150°s−1, 300°s−1) from which peak torque was determined. Electromyographic activity of the vastus medialis was also collected. Results: Repeated measures analysis of variance indicated that muscle torque production was significantly higher (P = 0.02) with caffeine compared with placebo. A significant (P = 0.02) substance by velocity interaction for muscle activity indicated significantly higher vastus medialis muscle activity in the presence of caffeine versus placebo, and this difference was amplified as angular velocity increased. Conclusions: Acute caffeine ingestion improves muscle performance and increases muscle activity during short‐duration maximal dynamic contractions. Muscle Nerve 50: 523–527, 2014
Efficient methods for implicit geometrical representation of complex material microstructures
Authors: Yuan Rui , Singh Sudhanshu S. , Chawla Nikhilesh , Oswald Jay 
Published: January 2014

SUMMARYWe present two methods for initializing distance functions on adaptively‐refined finite element meshes to represent complex material microstructures from segmented x‐ray tomographic data. Implicit microstructure representation combined with the extended FEM allows modelers to represent complex material microstructures with consistent mesh quality and accuracy. In the first method, a level set evolution equation is formulated and solved by the Galerkin method on an adaptively‐refined mesh. We show that the convergence and stability of this method is optimal for the order of elements used. In the second approach, we initialize the distance field by the fast marching method on a uniform grid, and then project the solution onto the finite element mesh by least‐squares. We show that this latter approach is superior in speed and accuracy. As an example problem, both methods are demonstrated in the initialization of distance fields for two inclusion phases within a Al‐7075 alloy. Copyright © 2014 John Wiley & Sons, Ltd.
New strategies for some issues of numerical manifold method in simulation of crack propagation
Authors: Zheng Hong , Xu Dongdong 
Published: January 2014

SUMMARYAiming to solve, in a unified way, continuous and discontinuous problems in geotechnical engineering, the numerical manifold method introduces two covers, namely, the mathematical cover and the physical cover. In order to reach the goal, some issues in the simulation of crack propagation have to be solved, among which are the four issues to be treated in this study: (1) to reduce the rank deficiency induced by high degree polynomials as local approximation, a new variational principle is formulated, which suppresses the gradient‐dependent DOFs; (2) to evaluate the integrals with singularity of 1/r, a new numerical quadrature scheme is developed, which is simpler but more efficient than the existing Duffy transformation; (3) to analyze kinked cracks, a sign convention for argument in the polar system at the crack tip is specified, which leads to more accurate results in a simpler way than the existing mapping technique; and (4) to demonstrate the mesh independency of numerical manifold method in handling strong singularity, a mesh deployment scheme is advised, which can reproduce all singular locations of the crack with regard to the mesh. Corresponding to the four issues, typical examples are given to demonstrate the effectiveness of the proposed schemes. Copyright © 2013 John Wiley & Sons, Ltd.
Serum levels of arachidonic acid metabolites change during prostate cancer progression
Authors: Rodríguez‐Blanco Giovanny , Burgers Peter C. , Dekker Lennard J. M. , IJzermans Jan J. N. , Wildhagen Mark F. , Schenk‐Braat Ellen A. M. , Bangma Chris H. , Jenster Guido , Luider Theo M. 
Published: January 2014

BACKGROUNDArachidonic acid (AA) pathway has been shown to play a role in the development and progression of prostate cancer (PCa). In this study we aimed to assess the changes in concentrations of hydroxyeicosatetraenoic acids (HETEs) in serum samples from patients diagnosed with PCa compared to controls.METHODSHETEs were determined using ultrahigh pressure liquid chromatography‐tandem mass spectrometry (UHPLC‐MS/MS).RESULTSElevated concentrations of 5‐HETE, 8‐HETE, 11‐HETE and 15‐HETE were observed in 6 out of 20 patients diagnosed with PCa; no statistical differences with controls were observed for 12‐HETE and AA in the discovery set. An independent validation set composed of 222 samples divided in five groups ranging from subjects with low PSA and no PCa, to patients with advanced PCa was included. In 30% of the patients in the advanced PCa group, up to ten times higher concentrations of the same set of HETEs were observed with a significant concomitant decrease of the concentration of AA. Logistic regression and Kaplan–Meier curves illustrate that a decreased concentration of AA is a predictor of PCa biochemical recurrence after radical prostatectomy (RP).CONCLUSIONSFrom the present study we conclude that a significant association between AA and AA metabolites in serum and PCa progression exists, although serum concentrations of HETEs exhibited low sensitivity toward the diagnosis of PCa. Prostate 74:618–627, 2014. © 2014 Wiley Periodicals, Inc.
Synoptic‐scale dust emissions over the Sahara Desert initiated by a moist convective cold pool in early August 2006
Authors: Bou Karam Diana , Williams Earle , Janiga Matthew , Flamant Cyrille , McGraw‐Herdeg Michael , Cuesta Juan , Auby Antoine , Thorncroft Chris 
Published: January 2014

This article is concerned with a dust‐raising cold pool over the Sahara desert that occurred on 3–5 August 2006. Both the quantity of the uplifted dust and its spatio‐temporal evolution are examined using satellite observations and a numerical simulation. The dust emission during this event was initiated by a mesoscale cold pool emanating from mesoscale convective systems (MCSs) that developed over northern Niger and Mali on 3 August. This event is one of several exceptional northward surges of the West African Monsoon (WAM) during the 2006 wet season. We examine the propagation of the cold pool and associated dust lofting using high temporal resolution false‐colour dust product images from the Meteosat Second Generation Spinning Enhanced Visible and InfraRed Imager (MSG‐SEVIRI). Observations from Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) are used to characterize the vertical structure of the dust cloud as it spreads over the Sahara and across the Atlantic coast. The European Centre for Medium‐range Weather Forecasts African Monsoon Multidisciplinary Analysis (ECMWF‐AMMA) special reanalysis was used to describe the synoptic conditions that accompanied this event. Furthermore, a numerical simulation using the mesoscale model MesoNH was performed to estimate the emissions and the westward transport of dust during this event. MODIS aerosol optical depth (AOD) satellite imagery has then been used to track the dust plume across the Atlantic Ocean to Barbados, where comparisons are made with the local dust record there.The dusty cold pool covered southern Algeria and a large part of northern Mali and western Niger attaining a total area close to 2 × 106 km2. It extended over 2–3 km in altitude and had an AOD on the order of 1.5 and an estimated total dust load of about 1.5 Tg on average. Following daytime heating, the dusty cold pool and associated northward surge of moisture favoured the development of new convection and additional precipitation over the Sahara. The northward extension of the dusty cold pool was accompanied by a collapse of the Saharan heat‐low, a characteristic feature of monsoon surges. A model‐estimated quantity of 0.4 Tg of the dust produced during this event was subjected to westward transport toward the Atlantic Ocean after being mixed upward in the thickening boundary layer by the daytime heating over the Sahara to altitudes as high as 5–6 km. The arrival of the dust plume in Barbados in the Caribbean Sea 9 days after its departure from the west coast of Africa was characterized by a peak in dust concentration of 48.5 µg m−3.
Forces exerted during microneurosurgery: a cadaver study
Authors: Marcus Hani J. , Zareinia Kourosh , Gan Liu Shi , Yang Fang Wei , Lama Sanju , Yang Guang‐Zhong , Sutherland Garnette R. 
Published: January 2014

AbstractBackgroundA prerequisite for the successful design and use of robots in neurosurgery is knowledge of the forces exerted by surgeons during neurosurgical procedures. The aim of the present cadaver study was to measure the surgical instrument forces exerted during microneurosurgery.MethodsAn experimental apparatus was set up consisting of a platform for human cadaver brains, a Leica microscope to provide illumination and magnification, and a Quanser 6 Degrees‐Of‐Freedom Telepresence System for tissue manipulation and force measurements.ResultsThe measured forces varied significantly depending on the region of the brain (P = 0.016) and the maneuver performed (P < 0.0001). Moreover, blunt arachnoid dissection was associated with greater force exertion than sharp dissection (0.22 N vs. 0.03 N; P = 0.001).ConclusionsThe forces necessary to manipulate brain tissue were surprisingly low and varied depending on the anatomical structure being manipulated, and the maneuver performed. Knowledge of such forces could well increase the safety of microsurgery. © 2014 The Authors. The International Journal of Medical Robotics and Computer Assisted Surgery published by John Wiley & Sons, Ltd.
Smart gateways for terabit/s satellite
Authors: Jeannin Nicolas , Castanet Laurent , Radzik José , Bousquet Michel , Evans Barry , Thompson Paul 
Published: January 2014

SUMMARYTo reach the terabit per second of throughput, telecommunication satellites cannot make use of frequency below Ka band only. Therefore, the use of broad portion of the spectrum available at Q/V (40/50 GHz) band is foreseen for the feeder link. This study presents the evaluation of performances of different macro‐diversity schemes that may allow mitigating the deep fades experienced at Q/V bands by introducing cooperation and a limited redundancy between the different gateways of the system. Two different solutions are firstly described. The performances resulting from the use of those assumptions are derived in a second stage. Copyright © 2014 John Wiley & Sons, Ltd.
Security enhancement of the authenticated RFID security mechanism based on chaotic maps
Authors: Benssalah Mustapha , Djeddou Mustapha , Drouiche Karim 
Published: January 2014

ABSTRACTWith the fast growth of the automatic authentication and asset tracking usage in a wide variety of applications in different fields, government, logistics, transportation and retail are among the most supportive of the radio‐frequency identification (RFID) market. Security is a crucial issue and must be addressed seriously. RFID security must meet the public demand of data protection. Recently, several lightweight RFID authentication protocols conforming to the EPCglobal Class 1 Generation 2 (EPC C1‐G2) standard have been proposed. In this paper, we present efficient attacks against the authenticated RFID security mechanism of Chang et al. based on Chebyshev chaotic maps, which is the first solution that adopted the chaos in the RFID authentication process. It turns out that this protocol has fundamental weaknesses that can be used by an adversary to break the system. We will show that this protocol is vulnerable to tracking attack, secret disclosure attack, impersonation attack and desynchronization attack. The proposed attack techniques are in light of two flaws related to the message generation and the shared‐secret update process, which are not neatly scrutinized. Then, we propose an improved RFID authentication protocol based on the Chebyshev chaotic map hard problem, conforming to the EPC C1‐G2 standard with more flexibility, security and mobility for the RFID application. Copyright © 2014 John Wiley & Sons, Ltd.
Einfluss von Querkraftanschlüssen auf das Biegedrillknicken von Einfeldträgern – Teil 1: Wissenschaftlicher Hintergrund
Authors: Mensinger Martin , Möller Heidrun 
Published: January 2014

AbstractQuerkraftanschlüsse stellen eine häufig verwendete oberkantenbündige Verbindungsmöglichkeit eines Nebenträgers an einen Hauptträger dar. Hierbei zeichnen sich insbesondere lange Fahnenblechanschlüsse durch ihre Vorteile in der Montage aus. Ausgeklinkte Träger mit Doppelwinkel‐ oder Fahnenblechanschlüssen müssen aufgrund der Ausklinkung des Nebenträgers umständlich zwischen die Hauptträger eingeschwenkt werden, stellen aber nichts desto trotz eine gerne verwendete Anschlussform mit großer Tradition dar. Allen Varianten gemein ist die Tatsache, dass sie kein Gabellager bilden sondern ein torsionsweiches Auflager. Damit sind die üblichen Berechnungsmöglichkeiten zur Ermittlung des idealen Biegedrillknickmomentes Mcr nicht anwendbar. Um für Träger mit diesen Anschlüssen Mcr ermitteln zu können und damit die Grundlage für einen normkonformen Nachweis zu legen, bedurfte es einiger eingehender Untersuchungen. Im Rahmen des AiF‐Forschungsvorhabens 16872 N wurden diese Untersuchungen am Lehrstuhl für Metallbau der Technischen Universität München durchgeführt. Der nachfolgende erste Teil des Beitrags beschäftigt sich mit den wissenschaftlichen Hintergründen.Influence of hinged connections on the lateral‐torsional buckling of single‐span beams – Part 1: Scientific background. Hinged connections are an often used type of connection between secondary and primary beam with flushed upper flanges. A very economic type of connection in terms of manufacturing and erection are long fin‐plates. Unfortunately they are no fork bearing, therefore the usual formula for the elastic critical moment Mcr for beams cannot be used. To design a beam according to DIN EN 1993‐1‐1 it is necessary to know the actual stiffness of such connections to be able to consider it in the calculation of Mcr. This is also the case for other typical hinged connections like notched beams with either fin‐plate or double angle connection. This problem of otherwise very economic connections is the reason for taking a closer look at their influence on the lateral‐torsional buckling in the research project AiF‐No. 16872 N at the Lehrstuhl für Metallbau der Technischen Universität München (Chair of Metal Structures at the TU München). The following first part of the paper deals with the scientific background.