bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Physical and Chemical Treatments on the Molecular Weight and Degradation of Alginate–Hydroxyapatite Composites
Authors: Cardoso Daniel Alves , Ulset Ann‐Sissel , Bender Johan , Jansen John A. , Christensen Bjørn E. , Leeuwenburgh Sander C. G.
Published: January 2014

Degradation of alginate remains a critical issue to allow predictable biological performance upon implantation of alginate‐based materials. Therefore, the objective of the current study is to compare the effects of γ‐irradiation (dry state, 20–80 kGy), partial (1 and 4%) periodate oxidation (aqueous solution), and autoclaving (dry state) on the molecular weight of alginate, as well as the degradation behavior of alginate‐based composites. The results show that γ‐irradiation is by far the most destructive technique characterized by strongly reduced molecular weights and rapid loss of composite integrity upon soaking in simulated body fluid. Partial periodate oxidation is less destructive as characterized by more moderate decreases in molecular weight, but the production of hydrolytically labile bonds compromises the integrity of the resulting composites. Autoclaving is shown to be a powerful tool to reduce the molecular weight of alginate in a controllable and mild manner without compromising the integrity of the resulting alginate–hydroxyapatite composites, simply by increasing the number of repetitive autoclaving cycles.
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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Positive solutions for an elliptic equation in an annulus with a superlinear nonlinearity with zeros
Authors: Iturriaga Leonelo , Massa Eugenio , Sánchez Justino , Ubilla Pedro
Published: January 2014

We study existence, multiplicity, and the behavior, with respect to λ, of positive radially symmetric solutions of in annular domains in . The nonlinear term has a superlinear local growth at infinity, is nonnegative, and satisfies for a suitable positive and concave function a. For this, we combine several methods such as the sub and supersolutions method, a priori estimates and degree theory.
Developing Sub‐Nanofibers in Electrospun Nylon‐6 Web by Controlling the Parameters of the Process
Authors: Rahmani H. , Karimi M.
Published: January 2014

The 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

Background

There 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.

Methods

Utilizing 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.

Results

A 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.

Conclusions

In 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

In 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

Emerging 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

This 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

Introduction: 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

Introduction: 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

We 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

Aiming 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.
Interest representation in Germany
Authors: Meier Dominik
Published: January 2014

The German public affairs sector has experienced considerable growth and noticeable changes since the millennium including the shift of the government seat from Bonn to Berlin. For a long time, public affairs was characterised by an effectively tripartite system composed of an interplay among state, economy and trade unions. Nowadays, observers recognise the emergence of a multitude of new players in this field and a fundamental change to a highly fragmented and extensive public affairs landscape. This development brought new challenges to the profession of interest representation. ‘Lobbying’ has become a highly discussed topic in the public debate carrying a rather negative connotation. Do we notice an increasing lack of transparency due to a multitude of players? How can we win back trust? First, this paper describes the need for interest representation and the necessity of defining political conditions for the public affairs sector within Germany. Second, the paper focuses on the development of the profession and addresses issues relating to the changes that have taken place in the course of time. Lastly, this article concludes with an evaluation of how public affairs and politics cope with the rising external and internal pressures in order to address current challenges and provide an outlook for future directions. Copyright © 2014 John Wiley & Sons, Ltd.
Reactivity of the intermediates of the reduction of SO2. Functionalization of graphite, graphite oxide and graphene oxide
Authors: Humeres Eduardo , de Castro Karen M. , Smaniotto Alessandra , Lopes Cristiane N. , Debacher Nito A. , Moreira Regina de F. P. M. , Schreiner Wido H. , Aliev Abil E.
Published: January 2014

Graphite particles (0.505 mm) were oxidized to graphite oxide with KClO3 in a H2SO4/HNO3 mixture. Graphite and graphite oxide particles were modified by reaction with SO2 at 630 °C. Thiolysis with sodium dodecane‐1‐thiolate and aminolysis with dodecane‐1‐amine of these particles occurred with the insertion of the organic moiety in the carbon matrix. Graphite microparticles (6.20 µm) were oxidized by H2SO4/ KMnO4/ H2O2 mixture and were exfoliated to graphene oxide sheets (MPGO). MPGO was modified by reaction with SO2 at 630 °C. The modified MPGO was refluxed in DMSO with dodecane‐1‐thiol, dodecane‐1‐amine, and hexadecane‐1‐bromide. The reactions occurred with the insertion of the organic moiety in the carbon matrix, according to the X‐ray photoelectron and nuclear magnetic resonance spectra. Mechanisms for the reactions were postulated using the atom inventory technique. Despite the structural differences, graphite, graphite oxide, and graphene oxide present the same selectivity for aminolysis and thiolysis reactions, with respect to the oxidized and non‐oxidized intermediates of the reduction of SO2, as was found for the activated carbon. Copyright © 2014 John Wiley & Sons, Ltd.
4‐Phenyl‐1,2,4‐triazoline‐3,5‐dione in the ene reactions with cyclohexene, 1‐hexene and 2,3‐dimethyl‐2‐butene. The heat of reaction and the influence of temperature and pressure on the reaction rate
Authors: Kiselev Vladimir D. , Kornilov Dmitry A. , Kashaeva Helen A. , Potapova Lyubov N. , Konovalov Alexander I.
Published: January 2014

The values of the enthalpy (53.3; 51.3; 20.0 kJ mol−1), entropy (−106; −122; −144 J mol−1K−1), and volume of activation (−29.1; −31.0; −cm3 mol−1), the reaction volume (−25.0; −26.6; −cm3 mol−1) and reaction enthalpy (−155.9; −158.2; −150.2 kJ mol−1) have been obtained for the first time for the ene reactions of 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione 1, with cyclohexene 4, 1‐hexene 6, and with 2,3‐dimethyl‐2‐butene 8, respectively. The ratio of the values of the activation volume to the reaction volume (∆V≠corr/ΔVr − n) in the ene reactions under study, 1 + 4→5 and 1 + 6→7, appeared to be the same, namely 1.16. The large negative values of the entropy and the volume of activation of studied reactions 1 + 4→ 5 and 1 + 6→7 better correspond to the cyclic structure of the activated complex at the stage determining the reaction rate. The equilibrium constants of these ene reactions can be estimated as exceeding 1018 L mol−1, and these reactions can be considered irreversible. Copyright © 2014 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

BACKGROUND

Arachidonic 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.

METHODS

HETEs were determined using ultrahigh pressure liquid chromatography‐tandem mass spectrometry (UHPLC‐MS/MS).

RESULTS

Elevated 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).

CONCLUSIONS

From 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.
Coupling a minimal stochastic lattice gas model of a cloud system to an atmospheric general circulation model
Authors: Ragone Francesco , Fraedrich Klaus , Borth Hartmut , Lunkeit Frank
Published: January 2014

We propose a strategy to couple a stochastic lattice gas model of a cloud system to a rather general class of convective parametrization schemes. As proposed in similar models recently presented in the literature, a cloud system in a grid box of a general circulation model (GCM) is modelled as a subgrid lattice of N elements that can be in one of S states, each corresponding to a different convective regime. The time evolution of each element of the lattice is represented as a Markov process characterized by transition rates dependent on large‐scale fields and/or local interactions. In order to make application to GCMs computationally feasible, we propose a reduction method leading to a system of S − 1 stochastic differential equations with multiplicative noise. The accuracy of the reduction method is tested in a minimal version of the model. The coupling to a convective scheme is performed in such a way that, in the limit of space‐ and time‐scale separation, the modified stochastic parametrization converges to the original deterministic version of the host scheme. Experiments with a real GCM are then performed, coupling the minimal version of the stochastic model to the Betts–Miller scheme in an aquaplanet version of the Planet Simulator. In this configuration, the stochastic extension of the parametrization keeps the climatology of its deterministic limit but strongly impacts the statistics of the extremes of daily convective precipitation.
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

Background

A 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.

Methods

An 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.

Results

The 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).

Conclusions

The 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

To 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

With 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

Querkraftanschlüsse 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.
Momententragfähigkeit schlanker Biegeträger – Einfluss des flanschinduzierten Stegblechbeulens
Authors: Unterweger Harald , Kettler Markus
Published: January 2014

Bei biegebeanspruchten Trägern mit sehr schlanken Stegen besteht die Gefahr des so genannten flanschinduzierten Stegblechbeulens – bzw. Gurtknickens – infolge der zusätzlich auftretenden Druckspannungen σz im Steg aus der Abtriebswirkung der beiden Gurte. Aktuell wird im Eurocode ein Grenzwert der Stegschlankheit hw/tw ausgewiesen, der diese Versagensform verhindern soll, demgegenüber schlankere Stege sind nicht erlaubt. Bei geringerer Stegschlankheit ist beim Beulnachweis des Steges keinerlei Interaktion mit der Abtriebswirkung der Gurte vorgesehen.

Nachfolgend wird, nach einer kurzen Darstellung des Hintergrundes zum Grenzwert der Stegschlankheit, systematisch auf die Momententragfähigkeit von Biegeträgern mit I‐Querschnitt, in Abhängigkeit der Stegschlankheit hw/tw – auch bei Überschreitung des Grenzwertes, eingegangen. Die numerisch ermittelten Momententragfähigkeiten werden mit jener der beiden Bemessungsmodelle des Eurocodes – Methode des effektiven Querschnitts und Methode der reduzierten Spannungen – verglichen.

Moment capacity of slender plate girders – Effect of flange induced buckling. For plate girders in bending with very slender webs the curvature due to bending along with the axial forces of the flanges generate transverse compression forces in the web, that are likely to produce web buckling. The current version of Eurocode gives a limit value for the web slenderness ratio hw/tw in order to avoid this phenomenon of flange induced buckling. Higher slenderness ratios are not within the scope of the code. For smaller slenderness ratios no interaction between buckling due to axial forces and transversal forces is considered.

Subsequently, after a short introduction on the limit slenderness ratio, the moment capacity of I shaped girders is systematically analysed as a function of the web slenderness ratio hw/tw – even for ratios higher than the limit value. The numerically determined moment capacities are then compared with the design criteria of Eurocode (i. e. effective widths method and reduced stress method).
Optimal placement of steel plate shear walls for steel frames by bat algorithm
Authors: Gholizadeh Saeed , Shahrezaei Amir Masoud
Published: January 2014

Layout optimization of steel frames with steel plate walls (SPWs) using a meta‐heuristic search algorithm is the main aim of the present study. SPWs are lateral load‐resisting systems, especially against earthquake excitation. These systems offer significant advantages in terms of cost, performance and ease of design compared with other systems. In this study, orthotropic membrane model is used to model the behaviour of steel plate shear walls. The newly developed bat algorithm, which is based on the echolocation behaviour of bats, is employed as the present study optimizer. Design variables of the optimization problem consist of the cross sections of beams and columns of the frame, the web plate thicknesses of SPWs and the placement of SPW in the frame. The bat algorithm performs suitable selection of sections from the AISC wide‐flange (W) shapes list. Strength constraints of the American Institute of Steel Construction Load and Resistance Factor Design and displacement constraints are checked during the optimization process. The results reveal the effectiveness of the proposed method for optimization of steel frames with SPWs. Copyright © 2014 John Wiley & Sons, Ltd.
Automated theorem proving
Authors: Plaisted David A.
Published: January 2014

Automated theorem proving is the use of computers to prove or disprove mathematical or logical statements. Such statements can express properties of hardware or software systems, or facts about the world that are relevant for applications such as natural language processing and planning. A brief introduction to propositional and first‐order logic is given, along with some of the main methods of automated theorem proving in these logics. These methods of theorem proving include resolution, Davis and Putnam‐style approaches, and others. Methods for handling the equality axioms are also presented. Methods of theorem proving in propositional logic are presented first, and then methods for first‐order logic. WIREs Cogn Sci 2014, 5:115–128. doi: 10.1002/wcs.1269

This article is categorized under:

Computer Science > Artificial Intelligence

Philosophy > Artificial Intelligence

Philosophy > Knowledge and Belief
Synthesis and Structure of Copper(II) Nitrate Complexes with 2, 6‐Bis(pyrazolyl)pyridine
Authors: Dolzhenko Vladimir D. , Kurnosov Nikon M. , Troyanov Sergey I.
Published: January 2014

Three mononuclear copper(II) complexes of copper nitrate with 2, 6‐bis(pyrazol‐1‐yl)pyridine (bPzPy) and 2, 6‐bis(3′,5′‐dimethylpyrazol‐1‐yl)pyridine (bdmPzPy), [Cu(bPzPy)(NO3)2] (1), [Cu(bPzPy)(H2O)(NO3)2] (2) and [Cu(bdmPzPy)(NO3)2] (3) were synthesized by the reaction of copper nitrate with the ligand in ethanol solution. The complexes have been characterized through analytical, spectroscopic and EPR measurements. Single crystal X‐ray structure analysis of complexes 1 and 2 revealed a five‐coordinate copper atom in 1, whereas 2 contains a six‐coordinate (4+2) CuII ion with molecular units acting as supramolecular nodes. These neutral nodes are connected through O–H···O(nitrate) hydrogen bonds to give couples of parallel linear strips assembled in 1D‐chains in a zipper‐like motif.
Chromium Tricarbonyl η6‐Complexes of [3]Cyclacene – A DFT Study
Authors: Türker Lemi
Published: January 2014

Chromium tricarbonyl η6 complexes of 3cyclacene are considered quantum chemically at the levels of B3LYP/6‐31G(d), B3LYP/6‐31++G(d, p), B3LYP/LANL2DZ, and RF/6‐31G(d, p)//B3LYP/6‐31++G(d, p). One of the complexes involves the top ring (A‐type) and the other one (B‐type) makes use of ring of the acene belt of the cyclacene in the complex formation. Energy calculations reveal that B‐type complex is more stable than A‐type. Some geometrical and quantum chemical properties were obtained. Additionally, vibrational and UV/Vis spectra of the complexes were produced.
Superconformal index and 3d-3d correspondence for mapping cylinder/torus
Authors: Gang Dongmin , Koh Eunkyung , Lee Sangmin , Park Jaemo
Published: January 2014

Abstract

We probe the 3d-3d correspondence for mapping cylinder/torus using the superconformal index. We focus on the case when the fiber is a once-punctured torus (Σ1,1). The corresponding 3d field theories can be realized using duality domain wall theories in 4d
$ \mathcal{N} $
 = 2∗ theory. We show that the superconformal indices of the 3d theories are the SL(2, C) Chern-Simons partition function on the mapping cylinder/torus. For the mapping torus, we also consider another realization of the corresponding 3d theory associated with ideal triangulation. The equality between the indices from the two descriptions for the mapping torus theory is reduced to a simple basis change of the Hilbert space for the SL(2,
$ \mathbb{C} $
) Chern-Simons theory on
$ \mathbb{R} $
 
× Σ1,1.
A Prospective Randomized Trial Comparing the Effectiveness of One versus Two (Staged) Corticosteroid Injections for the Treatment of Stenosing Tenosynovitis
Authors: Sheikh Emran , Peters John D. , Sayde Will , Maltenfort Mitchell , Leinberry Charles
Published: January 2014

Background

Stenosing tenosynovitis or trigger finger is a common clinical condition regularly treated with steroid injections. Varied success is reported at early time points following injection. We present a prospective, randomized IRB-approved study to confirm these findings at a long-term follow-up.

Methods

Adult patients presenting with symptoms of stenosing tenosynovitis who agreed to participate were randomized into two groups. Group 1 received an initial injection of triamcinolone and local anesthetic mixture. Group 2 received the same initial injection and an additional staged injection at 6 weeks. The patients were then followed beyond 2 years. If Group 1 patients were still symptomatic at 6 weeks, another injection was given. An additional injection or surgery was defined as treatment failure. DASH scores were obtained at baseline, 3, 6, and 12 months.

Results

Ninety-seven patients (101 trigger digits) were enrolled in the prospective trial. Fifty-six digits were randomized to the one-injection group versus 45 digits randomized to the two-injection group (“intention to treat analysis”—ITT). After accounting for crossover between the groups, 42 patients received one-injection versus fifty-nine patients receiving two injections (“actual” analysis). Overall failure was the same between the two groups. However, a higher surgery rate was noted for patients having undergone two injections versus one injection [47 % versus 27 % ( p<0.013), ITT]. Diabetes was associated with a higher surgery rate at 1 year within the group of overall failures [56 % versus 37 % ( p=0.0505), ITT]. High baseline DASH score (>40) was associated with a median time of 10 months for failure and 6 months for surgery as per a Kaplan-Meier survival analysis ( p<0.005 and p<0.001, respectively, ITT).

Conclusions

As overall failure of steroid injection for trigger finger is not improved with staged, two-injection treatment, we recommend a single injection initial treatment for trigger finger with a second injection given in cases of recurrence or failure. Diabetes was a risk factor for needing surgery if failure occurred within 1 year. The baseline DASH score is helpful in predicting which patients have a higher chance of failing as well as needing surgery.
Política de Emprendimiento en Colombia 2002-2010
Authors: Tarapuez Chamorro Edwin , Osorio Ceballos Hugo , Botero Villa Juan José
Published: January 2014

El artículo pretende determinar, bajo el enfoque de políticas públicas, los principales factores que condujeron a generar una política de emprendimiento en Colombia en el periodo 2002-2010, resaltando el papel del Servicio Nacional de Aprendizaje (SENA) y las universidades. El trabajo corresponde a una investigación exploratoria-descriptiva. Se utiliza información primaria (encuestas y entrevistas a expertos en el tema) y secundaria (revisión de documentos varios). Se obtienen dos lecciones principales: 1) para generar una política de emprendimiento no es condición previa contar con una ley o documento que la impulse, sino con voluntad política y visión clara de lo que se persigue por parte de los actores involucrados, y 2) las entidades gubernamentales que lideran su diseño y ejecución, al igual que sus directivos, deben contar al menos con amplia credibilidad, experiencia y estabilidad.
Cultura organizacional: evolución en la medición
Authors: Cújar Vertel Angélica del Carmen , Ramos Paternina Carlos David , Hernández Riaño Helman Enrique , López Pereira Jorge Mario
Published: January 2014

La cultura organizacional es conocida universalmente como el conjunto de significados compartidos y creencias en poder de una colectividad; su estudio evidenciará la forma como trabajan las empresas y las conductas que sus miembros toman al enfrentarse a diferentes situaciones. El presente artículo acerca al lector al concepto de cultura organizacional a partir de autores destacados en la historia, y registra el progreso cronológico en los métodos de medición, iniciando desde la observación y análisis psicológico hasta la elaboración de instrumentos especializados que midan el comportamiento de las personas y su influencia en la organización. Todo esto, con el fin de respaldar el avance científico regional, al considerar diversos estudios como precedente para futuras investigaciones.
Targeting of the MET receptor tyrosine kinase by small molecule inhibitors leads to MET accumulation by impairing the receptor downregulation
Authors: Leiser Dominic , Pochon Benoît , Blank-Liss Wieslawa , Francica Paola , Glück Astrid A. , Aebersold Daniel M. , Zimmer Yitzhak , Medová Michaela
Published: January 2014

The MET receptor tyrosine kinase is deregulated primarily via overexpression or point mutations in various human cancers and different strategies for MET inhibition are currently evaluated in clinical trials. We observed by Western blot analysis and by Flow cytometry that MET inhibition by different MET small molecule inhibitors surprisingly increases in a dose‐dependent manner total MET levels in treated cells. Mechanistically, this inhibition‐related MET accumulation was associated with reduced Tyr1003 phosphorylation and MET physical association with the CBL ubiquitin ligase with concomitant decrease in MET ubiquitination. These data may suggest careful consideration for design of anti‐MET clinical protocols.
Second cohomotopy and nonabelian cohomology
Authors: Pirashvili Mariam
Published: January 2014

The main difficulty in the theory of non-abelian cohomology is that for cosimplicial groups only zero-th and first dimensional cohomotopy are known. In this article we introduce a new class of cosimplicial groups, called centralised cosimplicial groups, for which we are able to define a second cohomotopy, with all expected properties. The main examples of such cosimplicial groups come from 2-categories.
Top management teams and performance in non-listed family firms
Authors: Cabrera-Suárez M Katiuska , Martín-Santana Josefa D
Published: January 2014

Supporting on recent theoretical approaches to the concept of familiness based on the notion of social capital, this study analyzes the composition of top management teams in non-listed family firms and its effect on the performance of these firms. An empirical analysis comprising 929 Spanish private family firms highlights the positive and significant influence of the inclusion of non-family managers, the family nature of top executives, as well as the presence of the founder. The study includes no significant results regarding homogeneity within family managers, or the interaction between a top family executive and the proportion of non-family managers.
The impact of comparative state-directed development on working conditions and employee satisfaction
Authors: Westover Jonathan H
Published: January 2014

In this research, I apply and extend Kohli's state-directed development framework to better understand country-level factors influencing cross-national differences in job characteristics and job satisfaction. Prior research has indicated that the nature of work has changed dramatically in recent years in response to economic shifts and an increasingly global economy. However, there is little agreement on whether the overall quality of work has improved or declined over that period and little is known about the overall comparative quality of work and job satisfaction across the global economy. In this study I use non-panel longitudinal data from the International Social Survey Program (survey questions on job characteristics and job quality) and various country-contextual variables. This article explores the impact of state-directed development on job satisfaction, first identifying and explaining the foundations of the statist literature, and then using various statistical methods to test for statistically significant impact and variation across countries.
How family control influences FDI entry mode choice
Authors: Kao Ming-Sung , Kuo Anthony , Chang Yi-Chieh
Published: January 2014

This study investigates how family control influences entry mode choice between joint ventures and wholly owned subsidiaries. Based on past studies revealing family-controlled firms’ unique concerns regarding the preservation of socioemotional wealth, the researchers posit that, firms with higher family control respond more drastically to perceived environmental uncertainty when choosing their entry mode. The researchers hypothesize that, when perceiving high environmental uncertainty, firms with higher versus lower family control are more likely to choose joint ventures. However, when perceiving low environmental uncertainty, firms with higher versus lower family control tend to choose wholly owned subsidiaries. The empirical results obtained from a sample of 1,644 investments undertaken by publicly listed companies in Taiwan support the hypotheses.
Higher-Level Conformal Blocks Divisors on
Authors: Alexeev Valery , Gibney Angela , Swinarski David
Published: January 2014

We study a family of semi-ample divisors on the moduli space of n-pointed genus 0 curves given by higher-level conformal blocks. We derive formulae for their intersections with a basis of 1-cycles, show that they form a basis for the Sn-invariant Picard group, and generate a full-dimensional subcone of the Sn-invariant nef cone. We find their position in the nef cone and study their associated morphisms.