bluuebunny/crossref_metadata_2025 huggingface dataset:
Die ersten Briefe Albert Einsteins an Arnold Sommerfeld: Erstveröffentlichung von bisher unbeachteten Briefen
Authors: Eckert M. , Pricha W.
Published: February 2013

Vor kurzem wurde in einem bislang unbeachteten Teilnachlaß Sommerfelds aus dem Institut für theoretische Physik der Universität München eine bedeutende und umfangreiche Korrespondenz gefunden — darunter auch vier Briefe Einsteins aus den Jahren 1908‐1910. Zusammen mit einem Brief vom 29. September 1909 aus der Dibner Library der Smithsonian Institution stellt dies die früheste, bis heute bekannte Korrespondenz von Einstein mit Sommerfeld dar [1]. Diese Briefe fehlen in dem in Buchform veröffentlichten Briefwechsel der beiden Gelehrten. (A. Hermann (Hrsg.): Albert Einstein/Arnold Sommerfeld. Briefwechsel. Sechzig Briefe aus dem goldenen Zeitalter der modernen Physik. Basel, Stuttgart: Schwabe u. Co. 1968) Die darin enthaltene und ausführlich kommentierte Korrespondenz umfaßt den Zeitraum 1912‐1954. Aus physikhistorischer Sicht ist der Wert der fünf Briefe kaum zu überschätzen, da sie Einblick in die frühe Diskussion über Relativität und Quanten gewährt. Leider befinden sich Sommerfelds Gegenbriefe weder im Einstein‐ noch im Sommerfeld‐Nachlaß.
Optimization of processing parameters for the synthesis of low‐density polyethylene/organically modified montmorillonite nanocomposites using X‐ray diffraction with experimental design
Authors: Campos‐Requena Víctor H , Rivas Bernabé L , Pérez Mónica A , Contreras David , Muñoz Eduardo
Published: February 2013

The influence of the processing parameters on the synthesis of low‐density polyethylene (LDPE)/organically modified montmorillonite (OMM) nanocomposite films was studied using experimental design. Intercalation in the nanocomposites was analysed using X‐ray diffraction and verified using atomic force microscopy. Four direct melt processing parameters were studied to obtain surface maps of intercalation in the nanocomposites: concentration of OMM (clay‐%), concentration of Polybond® 3149 (compatibilizer‐%), mixing temperature (Tmix) and mixing time. An ANOVA validated the polynomial function, and intercalation maps from response surface methodology (RSM) were obtained. The clay‐% parameter had the most significant effect, and Tmix showed no significant effect on intercalation (p < 0.05). A strong synergic interaction between clay‐% and compatibilizer‐% was observed, which is not possible to detect using univariate experiments. RSM provides a powerful tool for choosing the best processing conditions that lead to formulations with the highest intercalations by considering the main factors and their interactions. © 2013 Society of Chemical Industry
Change in I–V characteristics of thin‐film photovoltaic (PV) modules induced by light soaking and thermal annealing effects
Authors: Ishii Tetsuyuki , Otani Kenji , Takashima Takumi , Ikeda Kazuaki
Published: February 2013

The performance of photovoltaic (PV) modules is generally rated under standard test conditions (STC). However, the performance of thin‐film photovoltaic modules is not unique even under STC, because of the “metastability”. The effects of the light soaking and thermal annealing shall be incorporated into an appropriate energy rating standard. In this study, the change in I–V characteristics of thin‐film PV modules caused by the metastability was examined by repeated indoor measurements in addition to round‐robin outdoor measurements. The investigated thin‐film modules were copper indium gallium (di)selenide (CIGS), a‐Si : H, and a‐Si : H/µc‐Si : H (tandem) modules. The increase in the performance of the CIGS module between the initial and final indoor measurements was approximately 8%. Because of light‐induced degradation, the indoor performance of the a‐Si : H and a‐Si : H/µc‐Si : H modules decreased by approximately 35% and 20%, respectively. The performance was improved by about 4–6% under high temperature conditions after the initial degradation. The results suggest that the performance of thin‐film silicon modules can seasonally vary by approximately 4–6% only due to thermal annealing and light soaking effects. The effect of solar spectrum enhanced the outdoor performance of the a‐Si : H module by about 10% under low air mass conditions, although that of the a‐Si : H/µc‐Si : H modules showed a little increase. The currents of these a‐Si : H/µc‐Si : H modules may be limited by the bottom cells. Therefore, it is required to optimize the effect of solar spectrum in addition to the effects of light soaking and thermal annealing, in order to achieve the best performance for thin‐film silicon tandem modules. Copyright © 2013 John Wiley & Sons, Ltd.
Quantitative analysis of chaperone network throughput in budding yeast
Authors: Brownridge Philip , Lawless Craig , Payapilly Aishwarya B. , Lanthaler Karin , Holman Stephen W. , Harman Victoria M. , Grant Christopher M. , Beynon Robert J. , Hubbard Simon J.
Published: February 2013

The network of molecular chaperones mediates the folding and translocation of the many proteins encoded in the genome of eukaryotic organisms, as well as a response to stress. It has been particularly well characterised in the budding yeast, Saccharomyces cerevisiae, where 63 known chaperones have been annotated and recent affinity purification and MS/MS experiments have helped characterise the attendant network of chaperone targets to a high degree. In this study, we apply our QconCAT methodology to directly quantify the set of yeast chaperones in absolute terms (copies per cell) via SRM MS. Firstly, we compare these to existing quantitative estimates of these yeast proteins, highlighting differences between approaches. Secondly, we cast the results into the context of the chaperone target network and show a distinct relationship between abundance of individual chaperones and their targets. This allows us to characterise the ‘throughput’ of protein molecules passing through individual chaperones and their groups on a proteome‐wide scale in an unstressed model eukaryote for the first time. The results demonstrate specialisations of the chaperone classes, which display different overall workloads, efficiencies and preference for the sub‐cellular localisation of their targets. The novel integration of the interactome data with quantification supports re‐estimates of the level of protein throughout going through molecular chaperones. Additionally, although chaperones target fewer than 40% of annotated proteins we show that they mediate the folding of the majority of protein molecules (∼62% of the total protein flux in the cell), highlighting their importance.
Haloferax mediterraneiGlnK proteins are post‐translationally modified by uridylylation
Authors: Pedro‐Roig Laia , Camacho Mónica , Bonete María José
Published: February 2013

In this work we report for the first time a post‐translational modification of PII homologues from the Archaea Domain. Haloferax mediterranei is the first haloarchaea whose PII proteins have been studied, it possesses two of them (GlnK1 and GlnK2), both encoded adjacent to a gene for the ammonia transporter Amt. An approach based on 2DE, anti‐GlnK immunoblot and peptide mass fingerprint (MALDI‐TOF‐MS) of the reactive spots showed that GlnK proteins in H. mediterranei are post‐translationally uridylylated. A third spot with lower pI suggests the existence of a non‐descript post‐translational modification in this protein family.
Electroactive methacrylate‐based triblock copolymer elastomer for actuator application
Authors: Cho Kie Yong , Hwang Seung Sang , Yoon Ho Gyu , Baek Kyung‐Youl
Published: February 2013

A series of ABA triblock copolymers of methyl methacrylate (MMA) and dodecyl methacrylate (DMA) [poly(MMA‐b‐DMA‐b‐MMA)] (PMDM) were synthesized by Ru‐based sequential living radical polymerization. For this, DMA was first polymerized from a difunctional initiator, ethane‐1,2‐diyl bis(2‐chloro‐2‐phenylacetate) with combination of RuCl2(PPh3)3 catalyst and nBu3N additive in toluene at 80 °C. As the conversion of DMA reached over about 90%, MMA was directly added into the reaction solution to give PMDM with controlled molecular weight (Mw/Mn ≤ 1.2). These triblock copolymers showed well‐organized morphologies such as body centered cubic, hexagonal cylinder, and lamella structures both in bulk and in thin film by self‐assembly phenomenon with different poly(methyl methacrylate) (PMMA) weight fractions. Obtained PMDMs with 20–40 wt % of the PMMA segments showed excellent electroactive actuation behaviors at relatively low voltages, which was much superior compared to conventional styrene‐ethylene‐butylene‐styrene triblock copolymer systems due to its higher polarity derived from the methacrylate backbone and lower modulus. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
Chain transfer agents in cationic photopolymerization of a bis‐cycloaliphatic epoxide monomer: Kinetic and physical property effects
Authors: Dillman Brian , Jessop Julie L. P.
Published: February 2013

The effects of chain transfer agents (CTA) on cationic ring‐opening polymerization of 3,4‐epoxycyclohexylmethyl‐3′,4′‐epoxycyclohexane carboxylate (EEC) were explored. EEC was polymerized in the presence of various CTAs, and epoxide conversions monitored via Raman spectroscopy. Polymer films were prepared and analyzed by dynamic mechanical analysis. Many of the organic alcohols studied greatly enhanced epoxide polymerization rates and conversion levels. The gel fraction of polymer specimens decreased rapidly with increasing amounts of octanol (gel fraction >90% up to 0.3 equiv OH) but remained high with increasing amounts of 1,2‐propanediol (gel fraction >90% up to 0.6 equiv OH). Increasing the size of primary alcohols had little effect on the polymerization rates and conversions. The polymerization rate decreased with increasing alcohol substitution (1°>2°>3°). Acidic alcohols had very low impact on conversion and polymerization rates relative to the neat epoxy resin. The glass transition temperature was inversely related to the size and amount of CTA. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
Block copolystyrene derivatives having flexible alkylsulfonated side chains and hydrophobic alkoxy chains as a proton exchange membrane for fuel cell application
Authors: Sheng Li , Higashihara Tomoya , Maeda Rina , Hayakawa Teruaki , Ueda Mitsuru
Published: February 2013

A series of block copolystyrene derivatives, poly{[4‐(4‐sulfobutyloxy)styrene]x‐block‐[4‐(n‐butoxystyrene)]y} (PSBOSx‐b‐PnBOSy), containing a flexible alkylsufonated side chain and hydrophobic alkoxy chain with various ion exchange capacities (IECs) have been synthesized based on living anionic polymerization. The resulting crosslinked membranes were prepared using 4,4′‐methylene‐bis[2,6‐bis(hydroxyethyl)phenol] as the crosslinker in the presence of methanesulfonic acid. The crosslinked PSBOS2.2‐b‐PnBOS1 membrane with IEC of 2.89 mequiv g−1 displays a high proton conductivity (0.01 S cm−1) at 30% relative humidity and 80 °C, which is comparable to that of Nafion. The well‐developed phase separation and the continuous hydrophilic domains in the crosslinked PSBOS2.2‐b‐PnBOS1 membranes have been observed in a transmission electron microscope image. Moreover, the dynamic mechanical analysis measurement and Fenton's reagent testing show that the crosslinked PSBOSx‐b‐PnBOSy membranes have good mechanical properties and oxidative stability. These results indicate that the introduction of flexible alkylsulfonated side chains to the polystyrene main chains positively affect both the proton conductivity and oxidative stability. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
Diels‐alder click reaction for the preparation of polycarbonate block copolymers
Authors: Omurtag Pinar Sinem , Gunay Ufuk Saim , Dag Aydan , Durmaz Hakan , Hizal Gurkan , Tunca Umit
Published: February 2013

The Diels‐Alder reaction as a click reaction strategy is applied to the preparation of well‐defined polycarbonate (PC)‐block copolymers. A well‐defined α‐anthracene‐terminated polycarbonate (PC‐anthracene) is prepared using 9‐anthracene methanol as an initiator in the ring opening polymerization of benzyl 5‐methyl‐2‐oxo‐1,3‐dioxane‐5‐carboxylate in CH2Cl2 at room temperature for 5 h. Next, a well‐defined α‐furan protected maleimide‐terminated‐poly(ethylene glycol) (PEG11‐MI or PEG37‐MI), ‐poly(methyl methacrylate) (PMMA26‐MI), and ‐poly(ε‐caprolactone) (PCL27‐MI) were clicked with the PC‐anthracene at reflux temperature of toluene to yield their corresponding PC‐based block copolymers (PC‐b‐PEG, PC‐b‐PMMA, and PC‐b‐PCL). The homopolymer precursors and their block copolymers were characterized by using the GPC, NMR and UV analysis. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
Discharge Dynamics and Modes of an Atmospheric Pressure Non‐Equilibrium Air Plasma Jet
Authors: Xian YuBin , Wu ShuQun , Wang Zhan , Huang QuanJun , Lu XinPei , Kolb Juergen F.
Published: February 2013

A plasma jet operated with atmospheric pressure air is presented. Unlike the dynamics of plasma jets working with noble gases, the propagation of the jet that is operated with air is primarily determined by the gas flow. This jet can be generated by applying a continuous, i.e., DC high voltage. However, depending on the applied voltage and gas flow rate a true DC operation can be distinguished from a self‐pulsing mode. The gas temperature of the plasma plume when operated in the pulsed mode is lower than for the DC mode. Conversely, emission intensities of atomic oxygen, O, and nitrogen species, N2 and ${\rm N}_{2}^{ + } $, are much higher for the pulsed mode than observed for DC operation.

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Tailoring Surface Properties of Polymeric Separators for Lithium‐Ion Batteries by Cyclonic Atmospheric‐Pressure Plasma
Authors: Huang Chun , Lin Chi‐Cheng , Tsai Ching‐Yuan , Juang Ruey‐Shin
Published: February 2013

This paper reported surface modification and characterization of polymeric separators by cyclonic atmospheric‐pressure plasma for Li‐ion battery use. Water contact angles of the plasma‐modified polymeric separator decreased with increasing treatment time and plasma power. Variations in surface morphology and chemical structure of the plasma‐modified polymeric separators were confirmed by FESEM and XPS. XPS analysis revealed that the surfaces of plasma‐modified polymeric separators had significantly higher concentrations of oxygen functional groups. Moreover, the cyclonic atmospheric‐pressure plasma‐modified polymeric separators showed excellent performance in electrochemical measurements.

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Interaction of cisplatin with a CCHC zinc finger motif
Authors: Castiglione Morelli Maria Antonietta , Ostuni Angela , Cristinziano Pier Luigi , Tesauro Diego , Bavoso Alfonso
Published: February 2013

The interaction between cisplatin and an 18‐residue CCHC zinc finger motif derived from a retroviral nucleocapsid protein (PyrZf18) has been studied using UV–visible, CD and 1H NMR spectroscopies and ESI‐MS spectrometry.

Cisplatin irreversibly blocks the cysteine zinc binding groups in the free peptide and is able to slowly eject zinc from the zinc–peptide complex. The observed end product of the reaction with cisplatin is a complex in which only one ammonia molecule is coordinated to platinum. After an initial binding with two cysteine residues and the formation of the (PyrZf18)–platinum–(NH3)2 complex, a release of one ammonia molecule occurs because of trans‐labilization, and the third cysteine is coordinated, leading to a mixture of isomers and/or conformers of the (PyrZf18)–platinum–NH3 complex. The results are discussed with respect to the potential antiretroviral activity of platinum(II) compounds and to the possible interaction of cisplatin with the cellular nucleic acid binding proteins. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.
Study of silicon thin film solar cells with different back‐reflectors
Authors: Zhu H. , Huang Y. , Mai Y. , Wang Y. , Yin J. , Feng Y. , He T. , Gao J. , Wang Z. , Lan L. , Ni J. , Guan F. , Bai Y. , Ma Y. , Wan M.
Published: February 2013

In this study, hydrogenated amorphous silicon (a‐Si:H) single junction and amorphous/microcrystalline silicon tandem (a‐Si:H/µc‐Si:H) solar cells with different back‐reflectors (BRs) are systematically investigated. A novel white polyvinyl butyral (PVB) foil was used as BR. In addition, the specular aluminum (Al) films and rough Al films were deposited on back float glasses as BRs as well, which were integrated onto the front glass covered with solar cells by laminating with a transparent PVB encapsulation foil. It is found that both types of solar cells (a‐Si:H and a‐Si:H/µc‐Si:H) with white PVB foil BRs show a higher short circuit current density (Jsc) compared to the cells with a specular Al BR. It is mainly due to a high light scattering of white PVB foils. Moreover, the cell with a rough Al film BR shows a low Jsc close to that of cell without any BRs. The great light losses inside the solar cell may be mainly caused by the plasmonic absorption on the rough Al film surface. An a‐Si:H solar cell of 8.3% and an a‐Si:H/µc‐Si:H tandem solar cell of 10.1% were obtained, in which the white PVB foils were used as BRs.
Quantum critical transition from Kondo insulator to metallic state studied by band‐structure calculations for doped compounds: CeRhSb and CeNiSn
Authors: Goraus Jerzy , Ślebarski Andrzej
Published: February 2013

We present the ab initio calculations of the on‐site hybridization between Ce 4f and Ce 5d electrons as well as the Mulliken Ce 5d occupation for the doped Kondo insulators CeRhSb and CeNiSn. In our investigations we have examined the following series: CeRhSb1 − xSnx, CeRh1 − xPdxSb, CeRhSb1 − xTex, Ce1 − xLaxRhSb and CeNi1 − xCuxSn, CeNiSn1 − xSbxSb, Ce1 − xLaxNiSn. The transition from the Kondo insulator to the metallic state induced by doping at some critical concentration xc was recently reported for various dopants based on the resistivity, susceptibility and spectroscopic data. Our calculations show that both the Mulliken occupation of Ce 5d states and the onsite hybridization between Ce 4f and Ce 5d states exhibit critical behavior at nearly the same dopant concentrations as observed in experiment. We also note that for the CeRhSb‐based alloys the disorder is not necessary to explain their critical behavior, in contrast to the CeNiSn‐based series.
High pressure electrical resistivity and specific heat of the heavy fermion compound CeCoGe2.2Si0.8
Authors: Larrea J. J. , Teyssier J. , Rϕnnow H. M. , Lorenzer K.‐A. , Paschen S.
Published: February 2013

We study the evolution of the magnetic ground state close to the putative quantum critical point in CeCoGe2.2Si0.8 by using electrical resistivity and specific heat measurements under the same high hydrostatic pressure conditions. The electrical resistivity shows that the antiferromagnetic ordering temperature, TN, is suppressed above PC = 5.9 kbar, with the emergence of non‐Fermi liquid behavior. On the other hand, the specific heat shows two different magnetic transitions at 0 kbar, one at TN and another one at Tl ≈ 0.3 K. Both transition temperatures are reduced by pressure but remain finite up to at least 7.2 kbar. The height of the specific heat anomaly at TN, ΔCN, is strongly reduced above PC. These features suggest that the quantum criticality in CeCoGe2.2Si0.8 is governed by disorder.
Electronic nematicity and its relation to quantum criticality in Sr3Ru2O7 studied by thermal expansion
Authors: Stingl C. , Perry R. S. , Maeno Y. , Gegenwart P.
Published: February 2013

We report high‐resolution measurements of the in‐plane thermal expansion anisotropy in the vicinity of the electronic nematic phase in Sr3Ru2O7 down to very low temperatures and in varying magnetic field orientation. For fields applied along the c‐direction, a clear second‐order phase transition is found at the nematic phase, with critical behavior compatible with the two‐dimensional Ising universality class (although this is not fully conclusive). Measurements in a slightly tilted magnetic field reveal a broken fourfold in‐plane rotational symmetry, not only within the nematic phase, but extending towards slightly larger fields. We also analyze the universal scaling behavior expected for a metamagnetic quantum critical point, which is realized outside the nematic region. The contours of the magnetostriction suggest a relation between quantum criticality and the nematic phase.
Study of an auxetic structure made of tubes and corrugated sheets
Authors: Zhang Zhengkai , Hu Hong , Liu Shirui , Xu Binggang
Published: February 2013

Materials and structures with negative Poisson's ratio are characterized as auxetics. They are interesting for engineering applications due to their non‐conventional behavior. However, most of the auxetic structures suffer with a disadvantage that they are difficult to be fabricated because of their complicated geometry structure. To overcome this problem, an auxetic structure made of tubes and corrugated sheets using conventional technology is proposed in this study. Its auxetic effect is investigated by both geometrical analysis and finite element method. For validating the analyses, a real auxetic structure is made with aluminum material and tested under compression condition. All the results obtained show that the proposed structure has very significant negative Poisson's ratio effect under compression. The study has provided a simple way to fabricate auxetic structure for using in a wide range of industrial fields at a low cost.
High transconductance ion‐implanted GaN MISFETs using atomic layer deposited high‐k dielectrics
Authors: Gu S. , Katayose H. , Nomoto K. , Nakamura T. , Ohoka A. , Lee K. , Lu W. , Asbeck P. M.
Published: February 2013

We demonstrate MISFETs based on GaN p‐epilayers with ion‐implanted source/drain regions and atomic layer deposited (ALD) gate dielectrics of Al2O3 and HfO2. The fabrication technology is similar to that used for silicon MOSFETs. We find that there are significant shifts (of order 1 V) in threshold voltage between FETs produced with Al2O3 and HfO2 films, enabling depletion mode and enhancement mode device operation for the same substrate doping. The GaN MISFETs obtained maximum drain current of 580mA/mm and an extrinsic transconductance as high as 160 mS/mm. To the authors' knowledge, the transconductance achieved represents record performance for ion‐implanted MISFETs of GaN without heterostructure barriers. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A New Distribution‐free Control Chart for Joint Monitoring of Unknown Location and Scale Parameters of Continuous Distributions
Authors: Chowdhury S. , Mukherjee A. , Chakraborti S.
Published: February 2013

While the assumption of normality is required for the validity of most of the available control charts for joint monitoring of unknown location and scale parameters, we propose and study a distribution‐free Shewhart‐type chart based on the Cucconi statistic, called the Shewhart‐Cucconi (SC) chart. We also propose a follow‐up diagnostic procedure useful to determine the type of shift the process may have undergone when the chart signals an out‐of‐control process. Control limits for the SC chart are tabulated for some typical nominal in‐control (IC) average run length (ARL) values; a large sample approximation to the control limit is provided which can be useful in practice. Performance of the SC chart is examined in a simulation study on the basis of the ARL, the standard deviation, the median and some percentiles of the run length distribution. Detailed comparisons with a competing distribution‐free chart, known as the Shewhart‐Lepage chart (see Mukherjee and Chakraborti) show that the SC chart performs just as well or better. The effect of estimation of parameters on the IC performance of the SC chart is studied by examining the influence of the size of the reference (Phase‐I) sample. A numerical example is given for illustration. Summary and conclusions are offered. Copyright © 2013 John Wiley & Sons, Ltd.
SHIP‐LOCK–INDUCED SURGES IN AN IMPOUNDED RIVER AND THEIR IMPACT ON SUBDAILY FLOW VELOCITY VARIATION
Authors: Maeck A. , Lorke A.
Published: February 2013

The majority of large rivers are fragmented by dams, and navigation is often supported by the installation of ship locks. Despite their ubiquitous existence, the effect of ship locks on river basin hydrodynamics is rarely considered in an environmental context.

Ship‐lock operation induces single‐wave crests or troughs called surges, which propagate along the basin and are subject to reflection at the up‐ and downstream impoundments. We used pressure sensors and acoustic Doppler current profiler measurements to investigate the effects of up‐ and downstream ship locking on the water level and the current velocity dynamics in a 12.9‐km‐long basin of the impounded river Saar (Germany).

Ship lifting at the lower dam and the associated water export from the basin results in a negative surge propagating upstream, whereas a descending ship‐lock operation at the upper dam of the basin creates a positive surge propagating downstream. Both types of waves are subject to positive reflection at the opposing dams. Frequent lock operations lead to a complex pattern of multiple superimposing surges. The resulting water level fluctuations are comparable in magnitude with those associated with discharge variations due to hydropower peaking but occur at much shorter timescales. Associated with the water surface displacement during wave passage is a corresponding increase or decrease of the longitudinal current velocity. The magnitude of wave‐induced velocity fluctuations can exceed mean flow velocities by a factor of three and, depending on wave type and direction, can result in a reversal of the main flow direction of the river. Because of their longevity of several hours and superposition effects, ship‐lock–induced surges govern 66.3% and 45.4% of the subdaily variations in flow velocity and water level, respectively. This article concludes with a discussion of the potential effects of lock‐induced flow dynamics in impoundments on oxygen dynamics and methane ebullition. Copyright © 2013 John Wiley & Sons, Ltd.
Efficient group‐based authentication protocol for location‐based service discovery in intelligent transportation systems
Authors: Abrougui Kaouther , Boukerche Azzedine
Published: February 2013

Intelligent transportation systems have attracted many researchers. These latter have invested much effort to develop many applications and services mainly for vehicular systems. Services can be classified as safety or convenience services. A service discovery mechanism is needed to permit the discovery and the interaction with the existing services. However, so far security issues for service discovery in vehicular systems have not been widely considered, mainly for the convenience type of applications. Thus, a secure service discovery and communication protocol is necessary to prevent from many attacks and malicious processes in the vehicular system. In this paper, we investigate the possible attacks that can occur during the service discovery and communication processes. Then, we present our proposed group‐based authentication scheme for secure service discovery and communication in vehicular systems. Our proposed scheme is mainly dedicated for the convenience type of applications. We discuss the security requirements achieved by our proposed protocol and we report on its performance evaluation. We prove through our extensive set of simulations that our proposed scheme achieves a high success rate for the secure discovery of services, while maintaining the scalability of the network and low discovery delays. Copyright © 2013 John Wiley & Sons, Ltd.
Boron Nitride Nanotubes: Biocompatibility and Potential Spill‐Over in Nanomedicine
Authors: Ciofani Gianni , Danti Serena , Genchi Giada Graziana , Mazzolai Barbara , Mattoli Virgilio
Published: February 2013

Boron nitride nanotubes (BNNTs) represent an innovative and extremely intriguing class of nanomaterials. Thanks to their special chemical and physical characteristics, they have already found a large number of applications in the field of nanotechnology, and recent studies have shown their possible exploitation in the biomedical domain, both as nanocarriers and, more interestingly, as nanotransducers. In this review, the latest findings on the interactions between BNNTs and living systems are summarized, starting with the major issues of their stabilization in physiological media and their functionalization with bioactive molecules. Thereafter the biocompatibility data which have so far been made available are discussed, and the need for further extensive and standardized tests is highlighted. Finally, the appealing diagnostic and therapeutic opportunities offered by BNNT‐based systems are described, envisioning the potential spill‐over effects of such 'smart' and 'active' nanoparticles in nanomedicine.
Tuning the Stability of Graphene Layers by Phthalocyanine‐Based oPPV Oligomers Towards Photo‐ and Redoxactive Materials
Authors: Brinkhaus Linda , Katsukis Georgios , Malig Jenny , Costa Rubén D. , Garcia‐Iglesias Miguel , Vázquez Purificación , Torres Tomás , Guldi Dirk M.
Published: February 2013

In contrast to pristine zinc phthalocyanine (1), zinc phthalocyanine based oPPV‐oligomers (2–4) of different chain lengths interact tightly and reversibly with graphite, affording stable and finely dispersed suspensions of mono‐ to few‐layer graphene—nanographene (NG)—that are photoactive. The p‐type character of the oPPV backbones and the increasing length of the oPPV backbones facilitate the overall π–π interactions with the graphene layers. In NG/2, NG/3, and NG/4 hybrids, strong electronic coupling between the individual components gives rise to charge transfer from the photoexcited zinc phthalocyanines to NG to form hundreds of picoseconds lived charge transfer states. The resulting features, namely photo‐ and redoxactivity, serve as incentives to construct and to test novel solar cells. Solar cells made out of NG/4 feature stable and repeatable photocurrent generation during several ‘on‐off’ cycles of illumination with monochromatic IPCE values of around 1%.
Bifunctional Graphene/γ‐Fe2O3 Hybrid Aerogels with Double Nanocrystalline Networks for Enzyme Immobilization
Authors: Chen Liang , Wei Bin , Zhang Xuetong , Li Chun
Published: February 2013

Highly porous hosting materials with conducting (favorable to electron transfer) and magnetic (favorable to product separation) bicontinuous networks should possess great potentials for immobilization of various enzymes in the field of biocatalytic engineering, but the synthesis of such materials is still a great challenge. Herein, bifunctional graphene/γ‐Fe2O3 hybrid aerogels with quite low density (30–65 mg cm−3), large specific surface area (270–414 m2 g−1), high electrical conductivity (0.5–5 × 10−2 S m−1), and superior saturation magnetization (23–54 emu g−1) are fabricated. Single networks of either graphene aerogels or γ‐Fe2O3 aerogels are obtained by etching of the hybrid aerogels with acid solution or calcining of the hybrid aerogels in air, indicative of the double networks of the as‐synthesized graphene/γ‐Fe2O3 hybrid aerogels for the first time. The resulting bifunctional aerogels are used to immobilize β‐glucuronidase for biocatalytic transformation of glycyrrhizin into glycyrrhetinic acid monoglucuronide or glycyrrhetinic acid, with high biocatalytic activity and definite repeatability.
Automatic Segmentation of Method Code into Meaningful Blocks: Design and Evaluation
Authors: Wang Xiaoran , Pollock Lori , Vijay‐Shanker K.
Published: February 2013

Good programming practice and guidelines suggest that programmers use both vertical and horizontal spacing to visibly delineate between code segments that represent different algorithmic steps or high‐level actions. Unfortunately, programmers do not always follow these guidelines. Editors and integrated development environments (IDEs) can easily indent codes based on syntax, but they do not currently support automatic blank line insertion, which presents more significant challenges involving the semantics.

This paper presents and evaluates a heuristic solution to the automatic blank line insertion problem by leveraging both program structure and naming information to identify ‘meaningful blocks’, consecutive statements that logically implement a high‐level action. Our tool, SEGMENT, takes as input a Java method and outputs a segmented version that separates meaningful blocks by vertical spacing. We report on several studies involving human judgments to evaluate the effectiveness of the automatic blank line insertion algorithm, for different size methods and for different levels of programmer expertise. The results indicate strong positive overall opinion of SEGMENT's effectiveness in comparison with both developer‐written blank lines and blank lines inserted by newcomers to the code. The results vary only slightly among short and long methods, and among novice and advanced programmers. SEGMENT assists in making users obtain an overall picture of a method's actions and comprehend it quicker as well as provides hints for internal documentation placement. Copyright © 2013 John Wiley & Sons, Ltd.
Dichromatic dark matter
Authors: Bai Yang , Su Meng , Zhao Yue
Published: February 2013

Abstract

Both the robust INTEGRAL 511 keV gamma-ray line and the recent tentative hint of the 135 GeV gamma-ray line from Fermi-LAT have similar signal morphologies, and may be produced from the same dark matter annihilation. Motivated by this observation, we construct a dark matter model to explain both signals and to accommodate the two required annihilation cross sections that are different by more than six orders of magnitude. In our model, to generate the low-energy positrons for INTEGRAL, dark matter particles annihilate into a complex scalar that couples to photon via a charge-radius operator. The complex scalar contains an excited state decaying into the ground state plus an off-shell photon to generate a pair of positron and electron. Two charged particles with non-degenerate masses are necessary for generating this charge-radius operator. One charged particle is predicted to be long-lived and have a mass around 3.8 TeV to explain the dark matter thermal relic abundance from its late decay. The other charged particle is predicted to have a mass below 1 TeV given the ratio of the two signal cross sections. The 14 TeV LHC will concretely test the main parameter space of this lighter charged particle.
Etiology and Outcome of Acute Pancreatitis in Children in Kashmir (India). An Endemic Area of Hepatobiliary Ascariasis
Authors: Javid Gul , Zargar Showkat , Shah Altaf , Shoukat Abid , Iqball Asif , Gupta Amit
Published: February 2013

Background

The purpose of the present study was to determine the etiology, management, and outcome of acute pancreatitis (AP) in children in an endemic area of hepatobiliary ascariasis (HBA).

Methods

This was a prospective, hospital‐based study over a 9‐year period that included 156 children younger than 12 years of age who had a diagnosis of AP.

Results

Of the 156 patients, 71 were boys and 85 were girls with a mean age of 8.4 ± 1.5 years (range 3–12 years). The various factors contributing to AP were biliary ascariasis in 93 cases (60 %), gallstones 16 (10 %), trauma 5 (3 %), choledochal cyst 4 (3 %), impacted bile duct stone 3 (2 %), and gallbladder sludge 2 (1 %). Idiopathic group 33 cases (21 %). Diagnosis was based on clinical picture, abdominal ultrasonography, and elevated serum amylase level. Pancreatitis was mild in 113 (72 %) patients and severe in 43 (28 %). With conservative therapy, 123 patients (79 %) improved, whereas the remaining 33, who had intractable abdominal pain, cholangitis, or worsening cholecystitis, underwent emergency endoscopic retrograde cholangiopancreatography for removal of worms (26 patients) and stones in the bile duct (7 patients). Bile duct stones were extracted in all 7 patients with that condition, and worms were extracted from 23 of the 26 patients with ascariasis. Emergency surgery was performed in five patients. Three patients died. Pancreatitis recurred in 16 patients due to HBA.

Conclusions

Pancreatitis is not uncommon in children. Ascariasis is a leading cause of AP in endemic areas. Patients usually respond to conservative management, but endoscopic treatment is effective. Surgery is rarely required.
An Investigation of the Dynamic Processes Promoting Citizen Participation
Authors: Foster-Fishman Pennie G. , Collins Charles , Pierce Steven J.
Published: February 2013

This study expanded the citizen participation literature by examining the dynamic nature of citizen participation and the extent to which the factors associated with citizen participation may be moderated by resident leadership status. Longitudinal survey data collected from 542 residents in one small Midwestern city implementing a community change initiative provide some insight into the challenges surrounding the promotion of an active citizenry. Within this one community, citizenship behaviors of emergent resident leaders and residents uninterested in a leadership role were influenced, to some extent, by different factors and the importance of these factors shifted in only a 2 years time span. Future research is needed to determine if the dynamics uncovered in this study were due to the initiative or to the nature of citizen participation processes.
Positive solutions to Kirchhoff type equations with nonlinearity having prescribed asymptotic behavior
Authors: Li Fuyi , Shi Junping , Liang Zhanping
Published: February 2013

Existence and bifurcation of positive solutions to a Kirchhoff type equation

\begin{cases}
−\left(a + b\int \limits_{\Omega }|\mathrm{∇}u|^{2}\right)\mathrm{\Delta }u = \nu f(x,u), & \text{in }\Omega , \\
u = 0, & \text{on }\partial \Omega
\end{cases}

are considered by using topological degree argument and variational method. Here

f

is a continuous function which is asymptotically linear at zero and is asymptotically 3-linear at infinity. The new results fill in a gap of recent research about the Kirchhoff type equation in bounded domain, and in our results the nonlinearity may be resonant near zero or infinity.
The genetics and functional analysis of primary osteoarthritis susceptibility
Authors: Reynard Louise N. , Loughlin John
Published: February 2013

Recent genome-wide association scans (GWASs) along with several adequately powered candidate gene studies have yielded a number of risk alleles for osteoarthritis (OA). This number is now sufficiently large to allow conclusions to be drawn regarding the nature of genetic susceptibility, including the fact that the risk alleles have variable effects depending on sex, ethnicity and on the skeletal site of the disease. Several of the alleles that have emerged from the GWASs are within or close to highly plausible candidate genes, includingRUNX2andCHST11. However, the majority of risk alleles do not map to genes previously reported to play a role in musculoskeletal biology, indicating that the GWAS datasets are telling us something new about the OA disease process. Functional studies have so far revealed that effects on gene expression are likely to be one of the main mechanisms through which OA susceptibility is acting. Epigenetic mechanisms such as DNA methylation also influence OA risk, and integration of genetic, transcriptomic and epigenetic data will allow us to use the genetic discoveries for informed development of new OA biological treatments.
Dromions of flexural-gravity waves
Authors: Alam Mohammad-Reza
Published: February 2013

Here we show that weakly nonlinear flexural-gravity wave packets, such as those propagating on the surface of ice-covered waters, admit three-dimensional fully localized solutions that travel with a constant speed without dispersion or dissipation. These solutions, that are formed at the intersection of line-soliton mean-flow tracks, have exponentially decaying tails in all directions and are called dromions in contrast to lumps that decay only algebraically. We derive, by asymptotic expansion and assuming multiple scales for spatial and temporal variations, the three-dimensional weakly nonlinear governing equations that describe the coupled motion of the wavepacket envelope and the underlying mean current. We show that in the limit of long waves and strong flexural rigidity these equations reduce to a system of nonlinear elliptic–hyperbolic partial differential equations similar to the Davey–Stewartson I (DSI) equation, but with major differences in the coefficients. Specifically, and contrary to DSI equations, the elliptic and hyperbolic operators in the flexural-gravity equations are not canonical resulting in complications in analytical considerations. Furthermore, standard computational techniques encounter difficulties in obtaining the dromion solution to these equations owing to the presence of a spatial hyperbolic operator whose solution does not decay at infinity. Here, we present a direct (iterative) numerical scheme that uses pseudo-spectral expansion and pseudo-time integration to find the dromion solution to the flexural-gravity wave equation. Details of this direct simulation technique are discussed and properties of the solution are elaborated through an illustrative case study. Dromions may play an important role in transporting energy over the ice cover in the Arctic, resulting in the ice breaking far away from the ice edge, and also posing danger to icebreaker ships. In fact we found that, contrary to DSI dromions that only exist in water depths of less than 5 mm, flexural-gravity dromions exist for a broad range of ice thicknesses and water depths including values that may be realized in polar oceans.
Optimal Taylor–Couette flow: direct numerical simulations
Authors: Ostilla Rodolfo , Stevens Richard J. A. M. , Grossmann Siegfried , Verzicco Roberto , Lohse Detlef
Published: February 2013

We numerically simulate turbulent Taylor–Couette flow for independently rotating inner and outer cylinders, focusing on the analogy with turbulent Rayleigh–Bénard flow. Reynolds numbers of $R{e}_{i} = 8\times 1{0}^{3} $ and $R{e}_{o} = \pm 4\times 1{0}^{3} $ of the inner and outer cylinders, respectively, are reached, corresponding to Taylor numbers $Ta$ up to $1{0}^{8} $. Effective scaling laws for the torque and other system responses are found. Recent experiments with the Twente Turbulent Taylor–Couette (${T}^{3} C$) setup and with a similar facility in Maryland at very high Reynolds numbers have revealed an optimum transport at a certain non-zero rotation rate ratio $a= - {\omega }_{o} / {\omega }_{i} $ of about ${a}_{\mathit{opt}} = 0. 33$. For large enough $Ta$ in the numerically accessible range we also find such an optimum transport at non-zero counter-rotation. The position of this maximum is found to shift with the driving, reaching a maximum of ${a}_{\mathit{opt}} = 0. 15$ for $Ta= 2. 5\times 1{0}^{7} $. An explanation for this shift is elucidated, consistent with the experimental result that ${a}_{\mathit{opt}} $ becomes approximately independent of the driving strength for large enough Reynolds numbers. We furthermore numerically calculate the angular velocity profiles and visualize the different flow structures for the various regimes. By writing the equations in a frame co-rotating with the outer cylinder a link is found between the local angular velocity profiles and the global transport quantities.
Freeze-dried jaboticaba peel powder improves insulin sensitivity in high-fat-fed mice
Authors: Dragano Nathalia R. V. , Marques Anne y Castro , Cintra Dennys E. C. , Solon Carina , Morari Joseane , Leite-Legatti Alice V. , Velloso Lício A. , Maróstica-Júnior Mário R.
Published: February 2013

The peel of the native Brazilian fruit jaboticaba is rich in anthocyanins, which are known for their anti-obesity effects in animal models. The aim of the present study was to evaluate the effects of freeze-dried jaboticaba peel powder (FDJPP) on a number of metabolic parameters in a model of diet-induced obesity. Mice (n8 per group) were initially fed on a high-fat diet (HFD, 35 % w/w) for 4 weeks and then switched to a HFD supplemented with FDJPP (1, 2 or 4 % w/w) for an additional 6 weeks. Energy intake, weight loss, glucose tolerance, insulin resistance and lipid profile were determined, and the results were evaluated using ANOVA and Tukey's tests. The FDJPP exerted no protective effect on HFD-induced weight gain, hyperleptinaemia and glucose intolerance. However, the supplementation was effective to reduce insulin resistance, as evidenced in the insulin tolerance test, and subsequently confirmed by improved signal transduction through the insulin receptor/insulin receptor substrate-1/Akt/forkhead box protein pathway and by the attenuation of HFD-induced inflammation in the liver, verified by lower expressions of IL-1β and IL-6 and decreased phosphorylated IκB-α protein levels in all jaboticaba-treated mice. These results suggest that FDJPP may exert a protective role against obesity-associated insulin resistance.
The effect of dietary fibre on reducing the glycaemic index of bread
Authors: Scazzina Francesca , Siebenhandl-Ehn Susanne , Pellegrini Nicoletta
Published: February 2013

As bread is the most relevant source of available carbohydrates in the diet and as lowering dietary glycaemic index (GI) is considered favourable to health, many studies have been carried out in order to decrease the GI of bread. The most relevant strategy that has been applied so far is the addition of fibre-rich flours or pure dietary fibre. However, the effectiveness of dietary fibre in bread in reducing the GI is controversial. The purpose of the present review was to discuss critically the effects obtained by adding different kinds of fibre to bread in order to modulate its glycaemic response. The studies were selected because they analysedin vivowhether or not dietary fibre, naturally present or added during bread making, could improve the glucose response. The reviewed literature suggests that the presence of intact structures not accessible to human amylases, as well as a reduced pH that may delay gastric emptying or create a barrier to starch digestion, seems to be more effective than dietary fibrepersein improving glucose metabolism, irrespective of the type of cereal. Moreover, the incorporation of technologically extracted cereal fibre fractions, the addition of fractions from legumes or of specifically developed viscous or non-viscous fibres also constitute effective strategies. However, when fibres or wholemeal is included in bread making to affect the glycaemic response, the manufacturing protocol needs to reconsider several technological parameters in order to obtain high-quality and consumer-acceptable breads.
Chronic stressors and trauma: prospective influences on the course of bipolar disorder
Authors: Gershon A. , Johnson S. L. , Miller I.
Published: February 2013

Background

Exposure to life stress is known to adversely impact the course of bipolar disorder. Few studies have disentangled the effects of multiple types of stressors on the longitudinal course of bipolar I disorder. This study examines whether severity of chronic stressors and exposure to trauma are prospectively associated with course of illness among bipolar patients.

Method

One hundred and thirty-one participants diagnosed with bipolar I disorder were recruited through treatment centers, support groups and community advertisements. Severity of chronic stressors and exposure to trauma were assessed at study entry with in-person interviews using the Bedford College Life Event and Difficulty Schedule (LEDS). Course of illness was assessed by monthly interviews conducted over the course of 24 months (over 3000 assessments).

Results

Trauma exposure was related to more severe interpersonal chronic stressors. Multiple regression models provided evidence that severity of overall chronic stressors predicted depressive but not manic symptoms, accounting for 7.5% of explained variance.

Conclusions

Overall chronic stressors seem to be an important determinant of depressive symptoms within bipolar disorder, highlighting the importance of studying multiple forms of life stress.