bluuebunny/crossref_metadata_2025_split huggingface dataset:
A study of the stabilization of vertical alignment for liquid crystals by increasing the side‐chain rigidity of polyimides
Authors: Yi Long‐Fei , Xia Sen‐Lin , Sun Zhen , Liu Meng‐Si , Wang Ying‐Han 
Published: August 2012

AbstractA series of polyimides (PIs) with various side‐chain structures were prepared via copolymerization of pyromellitic dianhydride, 3,3′‐dimethyl‐4,4′‐methylenediamine and three functional diamines: 4‐(4‐octyloxybenzoyloxy)biphenyl‐3′,5′‐diaminobenzoate (C8‐BPDA), 4‐octyloxybiphenyl‐3′,5′‐diaminobenzoate (C8‐PDA) and 4‐(4‐butoxybenzoyloxy)biphenyl‐3′,5′‐diaminobenzoate (C4‐BPDA). PIs derived from C8‐BPDA and C4‐BPDA exhibited excellent rubbing resistance in comparison with PI from C8‐PDA and the pretilt angle could be controlled over 89° after rubbing. Thermogravimetric analysis showed that the thermal degradation of PIs under nitrogen atmosphere occurred above 320 °C, and PI derived from C8‐BPDA showed the best thermal stability. Wide‐angle X‐ray diffraction patterns indicated an amorphous morphology of the PIs, and the PIs also had outstanding solubility in polar aprotic solvents. The resultant PI films were light colored and maintained high transparency in the visible light region. By increasing the rigidity of side‐chains, the rubbing resistance and the thermal stability of PIs could be promoted at the same time. © 2012 Society of Chemical Industry
Exceptionally good, transparent and flexible FeS2/poly(vinyl pyrrolidone) and FeS2/poly(vinyl alcohol) nanocomposite thin films with excellent UV‐shielding properties
Authors: Sajimol Augustine M , Anand Puthirath B , Anilkumar Kollery M , Jayalekshmi Sankaran 
Published: August 2012

AbstractComposites of nanocrystalline iron disulfide (FeS2) coated with poly(vinyl pyrrolidone) (PVP) or poly(vinyl alcohol) (PVA) have been successfully synthesized using a solvothermal process, in which PVP and PVA serve as soft templates. Transparent, flexible thin films of these nanocomposites were prepared from homogeneous solution using a solution‐casting approach. X‐ray diffraction and thermogravimetric analysis and energy‐dispersive X‐ray, Fourier transform infrared and UV‐visible absorption spectroscopic techniques were employed to study the structural and optical properties of these nanocomposite films. UV‐visible spectra in transmission mode reveal the UV‐shielding efficiency of these nanocomposite films and the films are found to be exceptionally good for UV‐shielding applications in the wavelength range 200 to 400 nm. The present work aims at developing transparent and flexible UV‐shielding materials and colour filters using cost‐effective and non‐toxic inorganic–polymer nanocomposites. © 2012 Society of Chemical Industry
Psycho‐educational interventions for melanoma survivors: a systematic review
Authors: McLoone Jordana , Menzies Scott , Meiser Bettina , Mann Graham J. , Kasparian Nadine A. 
Published: August 2012

AbstractObjectiveTo systematically review psycho‐educational interventions developed for melanoma survivors.MethodsElectronic databases Medline, PsycINFO, Embase, and CINAHL were systematically searched using key words and subject headings for articles describing educational or psychological interventions designed specifically for people affected by melanoma.ResultsTwenty‐seven articles, generated by 16 unique interventions, were included for detailed review. Overall, educational interventions showed increased patient satisfaction with clinical care and information provision, as well as increased frequency of skin self‐examination, although accuracy and thoroughness of skin examination were seldom reported. Participation in psychological interventions was associated with decreases in anxiety, health‐related distress, and melanoma recurrence rates, as well as positive changes in coping with illness. Programs, when implemented as part of routine clinical care, were found to be cost‐effective.ConclusionsInterventions in this field vary widely, limiting the identification of ‘active ingredients' for psychological or behavioral change. Future intervention studies should ensure sufficient information is provided to support program replication and comprehensive assessment of program outcomes. Copyright © 2012 John Wiley & Sons, Ltd.
Suppression of short‐range scattering via hydrophobic substrates and the fractional quantum Hall effect in graphene
Authors: Hansel Stefan , Lafkioti Myrsini , Krstić Vojislav 
Published: August 2012

AbstractWe demonstrate that a hydrophobic layer between substrate and graphene largely eliminates Coulomb interaction between the graphene monolayer and charged impurities on the substrate, significantly reducing short‐range scattering. At high carrier concentrations the mobilities thus obtained, deliver a ratio of Coulomb scattering mean free path to average charge carrier separation comparable to that of the highest mobility samples that exhibit the fractional quantum Hall effect (FQHE). We observe the FQHE in the lowest mobility samples reported up to now and conclude that increasing the ratio of Coulomb scattering mean free path to charge carrier separation overcomes the limitations for the observation of the FQHE imposed by overall mobility. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Secure identity‐based multisignature schemes under quadratic residue assumptions
Authors: Wei Lifei , Cao Zhenfu , Dong Xiaolei 
Published: August 2012

ABSTRACTDigital signatures are one of the fundamental security primitives because they provide authenticity and nonrepudiation in the broadcast/multicast communication networks. However, the current broadcast/multicast authentication standards are vulnerable to signature flooding because excessive signature verification requests exhaust the computational resource of victims. The situation becomes worse in the case of the energy‐constrained networks such as wireless sensor networks and mobile ad hoc networks. As an essential variation of ordinary digital signature schemes, multisignature schemes enable a single compact signature to authenticate a message under a set of different signers. In this paper, we first propose an efficient identity‐based multisignature scheme with three interactive rounds under quadratic residue assumption, which equals to the large integer factoring assumption. By using the technique of quadratic residue‐based multiplicatively homomorphic equivocable commitment, an advanced identity‐based multisignature scheme is proposed to achieve to reduce the interactive round complexity to two rounds. We give the formal security proof that our schemes are existentially unforgeable under adaptively chosen message attacks and chosen identity attacks in the random oracle model. Compared with the previous work, our schemes are very efficient. In particular, our schemes are featured by the weak assumption and the efficient signing and verification procedures. Copyright © 2012 John Wiley & Sons, Ltd.
Secure group and multi‐layer group communication schemes based on polynomial interpolation
Authors: B. R. Purushothama , Amberker B. B. 
Published: August 2012

ABSTRACTSecure group communication model poses the challenge of key management to enforce the access control among the users of the group. Secure group key management schemes should be designed such that there is less rekeying and storage cost involved to manage the group keys. We propose a centralized, scalable, share‐based secure group key management scheme employing a new approach on the basis of the polynomial interpolation technique. We prove the security of the scheme. We design a multilayer share‐based key management scheme to manage the keys in the multilayer communication model. A new aggregate tree structure is proposed to manage the keys in the multilayer communication model. We analyze and evaluate the performance of the designed schemes in detail for storage and rekeying cost. We show that the proposed share‐based group key management scheme and the multilayer key management schemes are efficient in terms of storage and rekeying cost in comparison with two schemes based on threshold secret‐sharing method available in the literature. Copyright © 2012 John Wiley & Sons, Ltd.
A communication and computation‐efficient three‐party authenticated key agreement protocol
Authors: Tan Zuowen 
Published: August 2012

ABSTRACTThe three‐party authenticated key agreement protocol enables two clients to authenticate each other and agree on a session key over an insecure public network with the help of a trusted server. The password‐based three‐party authenticated key agreement protocols often have two drawbacks: (1) the server must store large numbers of passwords and (2) low‐entropy passwords easily suffer from potential guessing attacks. The public key infrastructure‐based three‐party authenticated key agreement protocols need no password. In 2008, Chen et al. proposed a round‐efficient three‐party authenticated key agreement protocol that needs no password or public key cryptosystem. However, the computation costs and communication loads of their protocol are still high. In 2009, Yang et al. proposed an efficient three‐party authenticated key exchange protocol based upon elliptic curve cryptography for mobile commerce environments. Unfortunately, both three‐party authenticated key agreement protocols are insecure. In this paper, we propose a novel three‐party authenticated key agreement protocol that requires neither public key cryptosystem nor password. Compared with the previous three‐party authenticated key agreement protocols, the novel three‐party authenticated key agreement protocol requires considerably fewer rounds, lower communication cost and smaller computation cost. The comparisons have shown that our three‐party authenticated key agreement protocol is more practical than other three‐party authenticated key agreement protocols. The proposed protocol is provably secure on the basis of the intractability of the computational Diffie–Hellman problems in the random oracle model. Copyright © 2012 John Wiley & Sons, Ltd.
Distributed monitoring for misbehaviour detection in wireless sensor networks
Authors: Benahmed Khelifa , Merabti Madjid , Haffaf Hafid 
Published: August 2012

ABSTRACTWireless sensor networks (WSNs) often consist of tiny devices and offer a variety of potential means to monitor the environment. However, WSNs are vulnerable to several types of attack because of their use in critical applications, their deployment in open and unprotected environments and their limited system resources. Therefore, security design is an important aspect of WSNs. In this work, we focus on detecting misbehaving nodes in WSNs. To the best of our knowledge, we are the first to present a complete and formal study on finding optimised monitor nodes and combining the organisation of the network with monitoring for misbehaviour detection in WSNs. The main idea of this work is to propose simple and efficient distributed monitoring algorithm capable of detecting misbehaviours based on a clustered architecture, where the cluster head is elected according to a new set of metrics. These new election metrics are based on a multiple‐criteria decision approach in order to monitor the health status of cluster members and detect misbehaviour. Our proposed strategy ensures a good selection of the nodes responsible for monitoring, reduces energy consumption during the monitoring process—effectively reducing the amount of security information that flows through the network—and reduces latency. The efficiency of our method is evaluated through simulation experiments. Copyright © 2012 John Wiley & Sons, Ltd.
A new versatile system for rapid control of gene expression in the fission yeast Schizosaccharomyces pombe
Authors: Zilio Nicola , Wehrkamp‐Richter Sophie , Boddy Michael Nicholas 
Published: August 2012

AbstractThe ability to regulate the expression of a gene greatly aids the process of uncovering its functions. The fission yeast Schizosaccharomyces pombe has so far lacked a system for rapidly controlling the expression of chromosomal genes, hindering its full potential as a model organism. Although the widely used nmt1 promoter displays a wide dynamic range of activity, it takes > 14–15 h to derepress. The urg1 promoter also shows a large dynamic range and can be induced quickly (< 2 h), but its implementation requires laborious strain construction and it cannot be used to study meiosis. To overcome these limitations, we constructed a tetracycline‐regulated system for inducible expression of chromosomal genes in fission yeast, which is easily established and implemented. In this system the promoter of a gene is replaced by simple one‐step substitution techniques with a tetracycline‐regulated promoter cassette (tetO7–TATACYC1) in cells where TetR/TetR′‐based transcription activators/repressors are also produced. Using top1 and nse6 as reporter genes, we show that Top1 and Nse6 appear after just 30 min of activating tetO7–TATACYC1 and plateau after ~4–6 h. The amount of synthesised protein is comparable to that produced from the attenuated nmt1 promoter Pnmt8, which should be closer to wild‐type levels for most genes than those generated from excessively strong promoters and can be controlled by changing the concentration of the effector antibiotic. This system also works efficiently during meiosis, thus making it a useful addition to the toolkit of the fission yeast community. Copyright © 2012 John Wiley & Sons, Ltd.
The mechanism of olfactory organ ventilation in Periophthalmus barbarus (Gobiidae, Oxudercinae)
Authors: Kuciel Michał 
Published: August 2012

AbstractPeriophthalmus barbarus Linnaeus, 1766 has many adaptations for amphibious life as a consequence of tidal zone occupation. One of them is the ability to keep a little amount of water and air in mouth while on land or in hypoxic water, correlated with closing a gill lid for gas exchange improvement. It causes that mechanisms of olfactory organ ventilation described in other species of actinopterygians (compression of accessory nasal sac(s) by the skull and jaw elements while mouth and gill lid moving) are not in operation. There is a specific mechanism of olfactory organ ventilation independent on jaw and skull elements movements. Compression of accessory nasal sacs is possible by a0 contraction and it is a movement effect on bones combined by ligaments. This process can be observed on P. barbarus as lifting the rostral part of the head.
Anorexia/cachexia of chronic diseases: a role for the TGF‐β family cytokine MIC‐1/GDF15
Authors: Tsai Vicky W. W. , Husaini Yasmin , Manandhar Rakesh , Lee-Ng K. K. Michelle , Zhang Hong Ping , Harriott Kate , Jiang Lele , Lin Shu , Sainsbury Amanda , Brown David A. , Breit Samuel N. 
Published: August 2012

Anorexia/cachexia is a common and currently mostly untreatable complication of advanced cancer. It is also a feature of a number of chronic diseases and can also occur as part of the normal ageing process. Over recent years, two different, but sometimes overlapping, processes have been identified to mediate anorexia/cachexia: those that act primarily on muscle reducing its mass and function, and processes that decrease nutrition leading to loss of both fat and muscle. In the case of at least some cancers, the latter process is sometimes driven by marked overexpression of macrophage inhibitory cytokine‐1/growth differentiation factor 15 (MIC‐1/GDF15). MIC‐1/GDF15 is a transforming growth factor beta (TGF‐β) family cytokine that is found in the serum of all normal individuals at an average concentration of about 0.6 ng/ml. Its increased expression in both cancers and other diseases can result in 10–100‐fold or more elevation of its serum levels. In experimental animals, serum MIC‐1/GDF15 levels at the lower end of this range induce anorexia by direct actions of the circulating cytokine on feeding centres in the brain. Mice with tumours overexpressing MIC‐1/GDF15 display decreased food intake, loss of lean and fat mass and cachexia. That this process also mediates anorexia/cachexia in humans is suggested by the fact that there is a direct correlation between the degree of serum MIC‐1/GDF15 elevation and the amount of cancer‐related weight loss, the first such relationship demonstrated. Further, in experimental animals, weight loss can be reversed by neutralisation of tumour‐produced MIC‐1/GDF15 with a specific monoclonal antibody, suggesting the possibility of effective therapy of patients with the devastating complication of anorexia/cachexia.
Construct Validity of a New Rating Scale for Self‐Reported Impairments in Persons With Late Effects of Polio
Authors: Brogårdh Christina , Lexell Jan , Lundgren‐Nilsson Åsa 
Published: August 2012

ObjectiveTo evaluate the construct validity of a new rating scale for self‐reported impairments in persons with late effects of polio.DesignPsychometric analysis of data on self‐perceived impairments in persons with prior polio.ParticipantsTwo hundred seventy‐three persons with prior polio (119 men and 154 women; mean age, 63.5 years).MethodRasch analysis of a 13‐item rating scale with 5 response categories, in which the participants rated how much they have been bothered by various post‐polio–related impairments during the past 2 weeks.ResultsThe initial analysis showed disordered categories, misfit with some of the items, multidimensionality, and local dependency. After adjustment of the categories, which resulted in a 4‐category rating scale, fit to the model was achieved, but the scale still showed signs of multidimensionality. Analyses of local dependency revealed correlations among some of the items, which resulted in a 5 testlet solution, which gave fit to the model and unidimensionality.ConclusionAfter adjustment of the categories and local dependency, this new rating scale, Self‐Reported Impairments in Persons With Late Effects of Polio, can be considered as unidimensional. The good psychometric properties implies that the Self‐Reported Impairments in Persons With Late Effects of Polio scale could be a useful rating scale that would increase our understanding of the impairments that persons with late effects of polio can experience. With further refinements, this scale may assist in the planning and evaluation of appropriate rehabilitation interventions.
Relationships of the Mediterranean dietary pattern with insulin resistance and diabetes incidence in the Multi-Ethnic Study of Atherosclerosis (MESA)
Authors: Abiemo Eunice E. , Alonso Alvaro , Nettleton Jennifer A. , Steffen Lyn M. , Bertoni Alain G. , Jain Aditya , Lutsey Pamela L. 
Published: August 2012

Type 2 diabetes (T2D) is a highly prevalent but preventable disorder. We assessed the association between an a priori Mediterranean diet (MeDiet) score and fasting glucose and insulin at baseline and incident T2D after a 6-year follow-up in the Multi-Ethnic Study of Atherosclerosis. Dietary intake was measured at baseline using a 127-item FFQ in 5390 men and women aged 45–84 years free of prevalent diabetes and clinical CVD. A MeDiet score was created based on the intake of ten food components: vegetables; whole grains; nuts; legumes; fruits; ratio of monounsaturated:saturated fat; red and processed meat; dairy products; fish; alcohol. Multivariable linear and proportional hazards models were used to estimate the association of the MeDiet, categorised in quintiles, with baseline insulin and glucose, and incident diabetes, respectively. The models were adjusted for demographic, physiological and behavioural characteristics. After multivariable adjustment, individuals with a higher MeDiet score had lower baseline mean insulin levels (Q1: 5·8 (95 % CI 5·6, 6·0) μmol/l; Q5: 4·8 (95 % CI 4·6, 5·0) μmol/l; P for trend < 0·0001). A higher MeDiet score was also associated with significantly lower glucose levels after basic adjustment, but was attenuated after adjustment for waist circumference. During the follow-up, 412 incident diabetes events accrued. The MeDiet was not significantly related to the risk of incident diabetes (P for trend = 0·64). In summary, greater consistency with a Mediterranean-style diet, reflected by a higher a priori MeDiet score, was cross-sectionally associated with lower insulin levels among non-diabetics, and with lower blood glucose before adjustment for obesity, but not with a lower incidence of diabetes.
Minimal spectral functions of an ordinary differential operator
Authors: Mogilevskii Vadim 
Published: August 2012

AbstractLetl[y]be a formally self-adjoint differential expression of an even order on the interval [0,b〉(b ≤ ∞) and letL0be the corresponding minimal operator. By using the concept of a decomposing boundary triplet, we consider the boundary problem formed by the equationl[y] − λy = f,f ∈ L2[0, b〉, and the Nevanlinna λ-dependent boundary conditions with constant values at the regular endpoint 0. For such a problem we introduce the concept of them-function, which in the case of self-adjoint separated boundary conditions coincides with the classical characteristic (Titchmarsh–Weyl) function. Our method allows one to describe all minimal spectral functions of the boundary problem, i.e. all spectral functions of the minimally possible dimension. We also improve (in the case of intermediate deficiency indicesn±(L0)and non-separated boundary conditions) the known estimate of the spectral multiplicity of the (exit space) self-adjoint extensionÃ ⊃ L0. Results are obtained for expressionsl[y]with operator-valued coefficients and arbitrary (equal or unequal) deficiency indicesn±(L0).
Singular solutions of a fully nonlinear 2 × 2 system of conservation laws
Authors: Kalisch Henrik , Mitrović Darko 
Published: August 2012

AbstractExistence and admissibility of δ-shock solutions is discussed for the non-convex strictly hyperbolic system of equationsThe system is fully nonlinear, i.e. it is nonlinear with respect to both unknowns, and it does not admit the classical Lax-admissible solution for certain Riemann problems. By introducing complex-valued corrections in the framework of the weak asymptotic method, we show that a compressive δ-shock solution resolves such Riemann problems. By letting the approximation parameter tend to zero, the corrections become real valued, and the solutions can be seen to fit into the framework of weak singular solutions defined by Danilov and Shelkovich. Indeed, in this context, we can show that every 2 × 2 system of conservation laws admits δ-shock solutions.
A higher category approach to twisted actions on c* -algebras
Authors: Buss Alcides , Meyer Ralf , Zhu Chenchang 
Published: August 2012

AbstractC*-algebras form a 2-category with *-homomorphisms or correspondences as morphisms and unitary intertwiners as 2-morphisms. We use this structure to define weak actions of 2-categories, weakly equivariant maps between weak actions and modifications between weakly equivariant maps. In the group case, we identify the resulting notions with known ones, including Busby–Smith twisted actions and the equivalence of such actions, covariant representations and saturated Fell bundles. For 2-groups, weak actions combine twists in the sense of Green, and Busby and Smith.The Packer–Raeburn Stabilization Trick implies that all Busby–Smith twisted group actions of locally compact groups are Morita equivalent to classical group actions. We generalize this to actions of strict 2-groupoids.
Commutative algebras in Drinfeld categories of abelian Lie algebras
Authors: Davydov Alexei , Futorny Vyacheslav 
Published: August 2012

AbstractWe describe (braided-) commutative algebras with non-degenerate multiplicative form in certain braided monoidal categories, corresponding to abelian metric Lie algebras (so-called Drinfeld categories). We also describe local modules over these algebras and classify commutative algebras with a finite number of simple local modules.