bluuebunny/crossref_metadata_2025_split huggingface dataset:
Finite element analysis of geometrically necessary dislocations in crystal plasticity
Authors: Hurtado Daniel E. , Ortiz Michael 
Published: June 2012

SUMMARYWe present a finite element method for the analysis of ductile crystals whose energy depends on the density of geometrically necessary dislocations (GNDs). We specifically focus on models in which the energy of the GNDs is assumed to be proportional to the total variation of the slip strains. In particular, the GND energy is homogeneous of degree one in the slip strains. Such models indeed arise from rigorous multiscale analysis as the macroscopic limit of discrete dislocation models or from phenomenological considerations such as a line‐tension approximation for the dislocation self‐energy. The incorporation of internal variable gradients into the free energy of the system renders the constitutive model non‐local. We show that an equivalent free‐energy functional, which does not depend on internal variable gradients, can be obtained by exploiting the variational definition of the total variation. The reformulation of the free energy comes at the expense of auxiliary variational problems, which can be efficiently solved using finite element approximations. The addition of surface terms in the formulation of the free energy results in additional boundary conditions for the internal variables. The proposed framework is verified by way of numerical convergence tests, and simulations of three‐dimensional problems are presented to showcase its applicability. A performance analysis shows that the proposed framework solves strain‐gradient plasticity problems in computing times of the order of local plasticity simulations, making it a promising tool for non‐local crystal plasticity three‐dimensional large‐scale simulations. Copyright © 2012 John Wiley & Sons, Ltd.
Structural Characterisation and Identification of Phenylethanoid Glycosides from Cistanches deserticola Y.C. Ma by UHPLC/ESI–QTOF–MS/MS
Authors: Han Lifeng , Boakye‐Yiadom Mavis , Liu Erwei , Zhang Yi , Li Wei , Song Xinbo , Fu Fenghua , Gao Xiumei 
Published: June 2012

ABSTRACTIntroductionPhenylethanoid glycosides (PhGs) are the major active constituents of Cistanches deserticola Y.C. Ma. However, the isolation, purification and identification procedures of PhGs are difficult and time‐consuming.ObjectiveTo establish a rapid and sensitive ultrahigh‐pressure liquid chromatography (UHPLC)/ESI (electrospray ion source)–quadrupole time of flight (QTOF)–MS/MS method that could be applied to rapidly profile and identify PhGs.MethodologySeven standard compounds were used for the investigation of the fragmentation pattern. Based on the UHPLC/ESI–QTOF–MS/MS method, the important structural information on the types of aglycone and saccharide sequences present should be obtained.ResultsAccording to the HPLC retention behaviour, the proposed fragmentation pathways provided by high‐resolution MS and MS/MS spectra and literature sources, a total of 13 PhGs in the crude extract of C. deserticola were identified or tentatively identified.ConclusionA rapid and accurate UHPLC/ESI–QTOF–MS/MS method was established for the identification of PhGs in the crude extract of C. deserticola. This method therefore can be used for rapid prediction of the chemical constituents and qualities of this plant. Copyright © 2012 John Wiley & Sons, Ltd.
Deposition of hard and adherent TiBCN films for cutting tools applications
Authors: Tillmann Wolfgang , Bejarano Gilberto , Hoffmann Fabian 
Published: June 2012

AbstractMetal cutting tools having wear resistant and chemically stable ceramic coatings are in many applications superior in performance to uncoated tools. Titanium boron carbon nitride (TiBCN) is a hard material particularly suitable as a protective coating for cutting tools due to its excellent properties, such as a high hardness and high wear and corrosion resistance, among other. TiBCN films were grown on Si (100) and high speed steel substrates by means of reactively pulsed DC magnetron sputtering technique. Two B4C‐ and two Ti‐targets, to which a pulsed DC voltage of middle frequency was applied, were used for the deposition of TiBCN. A chromium layer was first deposited to obtain a better adhesion of TiBCN to the substrates. The mechanical properties of these coatings deposited under different N2 contents were investigated. The substrates were biased through a medium frequency power supply. The bias voltage value was −90 V for all coatings. The total film thickness was maintained at approximately 2 µm. The hardness of the coatings increased with reduced nitrogen content, while the adhesion decreased from 40.8 to 24.2 N, and the wear rate increased from 0.154 to 0.744 × 10−16 m3/N.m, the latter probably caused by the low content of the self‐lubricating amorphous matrix of our coatings. However, the sample deposited by a nitrogen gas flow of 60 sccm presented a wear rate of four orders of magnitude smaller than the uncoated sample. The deposition method presented in this work seems very promising for the manufacture of TiBCN coatings.
Divide‐and‐conquer‐based quantum chemical study for interaction between HIV‐1 reverse transcriptase and MK‐4965 inhibitor
Authors: Saparpakorn Patchreenart , Kobayashi Masato , Hannongbua Supa , Nakai Hiromi 
Published: June 2012

AbstractMK‐4965, 3‐{5‐[(6‐Amino‐1H‐pyrazolo[3,4‐b]pyridine‐3‐yl)methoxy]‐2‐chlorophenoxy}‐5‐chloro‐benzonitrile, is a novel non‐nucleoside reverse transcriptase inhibitor (NNRTI) revealing high levels of potency against wild‐type (WT) the human immunodeficiency virus type‐1 (HIV‐1) and some important mutants. The divide‐and‐conquer (DC) based Hartree–Fock (HF) and second‐order Møller–Plesset perturbation theory (MP2) calculations were performed for the binding modes of MK‐4965 in the reverse transcriptase (RT) of the WT HIV‐1 and a mutant Y181C, 181 tyrosine mutated by cysteine. The binding pockets of MK‐4965 consisting of 19 residues are selected for the study. Numerical assessments confirmed the efficiency and accuracy of the DC‐MP2 method in comparison with the conventional MP2 one. Subsystem interaction energies obtained by the DC‐MP2 calculations clarified the key parts of the binding between MK‐4965 and HIV‐1: hydrogen bonding with 102 lysine, which is apart from mutated 181 residue. The present information can give a helpful guide for the future inhibitor design. © 2012 Wiley Periodicals, Inc.
Electrostatic potential effects of β‐cyclodextrin on optical properties of the 4‐dimethyl‐aminobenzonitrile
Authors: Nieto‐Malagón Guillermo , Hernández‐Pérez Julio M. , Vargas Rubicelia , Garza Jorge 
Published: June 2012

AbstractEffects of the electrostatic potential on absorption spectra of the 4‐dimethyl‐aminobenzonitrile (DMAB) were analyzed theoretically by methods based on the density functional theory. The electrostatic potential was imposed by three different ways: (a) applying a uniform electric field, (b) immersing the system within the cavity of the β‐cyclodextrin (BCD), (c) immersing the system in a cavity built with a charges set that fit to the electrostatic potential generated by the BCD, (d) a superposition of (b) or (c) with a continuum solvent model. The DMAB absorption spectra were estimated using the time dependent density functional theory with the Perdew, Burke, and Ernzerhof exchange–correlation functional. Additionally, to obtain the correct asymptotic behavior on the corresponding potential the van Leeuwen and Baerends proposal was used. The basis set effect on the predictions was estimated by comparing the TZVP and TZVP plus one additional diffuse function. We found that optical properties of the DMAB are modified in an important way if this system is immersed in an electrostatic potential imposed in several ways. By contrasting our theoretical results with the experimental observations we found that the effect observed on an optical sensor, designed with the BCD, and on the DMAB..BCD inclusion complex is due mainly by the electrostatic potential generated by the BCD. © 2012 Wiley Periodicals, Inc.
Relationship between local reactivity indices and the hammett constant for isatoic anhydride and its derivatives
Authors: Durand‐Niconoff José S. , Cruz‐Kuri Luis , Cruz‐Sánchez Jesús S. , Matus Myrna H. , Ramos‐Morales Fernando R. 
Published: June 2012

AbstractLocal reactivity is obtained for isatoic anhydride (ISA) (2H 3,1‐benzoxazin‐2,4(1H)‐dione) and 20 of its derivatives, using reactivity indices such as: local softness, condensed Fukui function, relative electrophilicity index, and relative nucleophilicity index. The local reactivity results for ISA show the best sites for a nucleophilic attack and for an electrophilic attack. A linear model is proposed from statistical methods to describe the substituent effect for the relationship between gas phase reactivity indices with respect to the Hammett constant values. © 2012 Wiley Periodicals, Inc.
Computational thermochemistry of glycolaldehyde
Authors: Bleda Erdi A. , Yavuz Ilhan , Altun Zikri , Trindle Carl 
Published: June 2012

AbstractWe use a variant of the focal point analysis to refine estimates of the relative energies of the four low‐energy torsional conformers of glycolaldehyde. The most stable form is the cis‐cis structure which enjoys a degree of H‐bonding from hydroxyl H to carbonyl O; here dihedral angles τ1 (OCCO) and τ2 (CCOH) both are zero. We optimized structures in both CCSD(T)/aug‐cc‐pVDZ and aug‐cc‐pVTZ; the structures agree within 0.01 Å for bond lengths and 1.0 degrees for valence angles, but the larger basis brings the rotational constants closer to experimental values. According to our extrapolation of CCSD(T) energies evaluated in basis sets ranging to aug‐cc‐pVQZ the trans‐trans form (180°, 180°) has a relative energy of 12.6 kJ/mol. The trans‐gauche conformer (160°, ±75°) is situated at 13.9 kJ/mol and the cis‐trans form (0°, 180°) at 18.9 kJ/mol. Values are corrected for zero point vibrational energy by MP2/aug‐cc‐pVTZ frequencies. Modeling the vibrational spectra is best accomplished by MP2/aug‐cc‐pVTZ with anharmonic corrections. We compute the Watsonian parameters that define the theoretical vibrational‐rotational spectra for the four stable conformers, to assist the search for these species in the interstellar medium. Six transition states are located by G4 and CBS‐QB3 methods as well as extrapolation using energies for structures optimized in CCSD(T)/aug‐cc‐pVDZ structures. We use two isodesmic reactions with two well‐established thermochemical computational schemes G4 and CBS‐QB3 to estimate energy enthalpy and Gibbs energy of formation as well as the entropy of the gas phase system. Our extrapolated electronic energies of species appearing in the isodesmic reactions produce independent values of thermodynamic quantities consistent with G4 and CBS‐QB3. © 2013 Wiley Periodicals, Inc.
Constructing protein nano‐fiber and estimation of the electronic state around metal ions
Authors: Komatsu Yu , Fukuda Masaki , Yamada Hironao , Kawamoto Shuhei , Miyakawa Takeshi , Morikawa Ryota , Takasu Masako , Yokojima Satoshi , Akanuma Satoshi , Yamagishi Akihiko 
Published: June 2012

AbstractWe aim to construct a nano‐fiber using proteins by mixing two kinds of proteins. The binding sites are expected to be formed between two α‐helices of one protein and two α‐helices of another protein. As model proteins, we use Lac repressor four helix protein (LARFH), sulerythrin, and 3‐isopropylmalate dehydrogenase. With these proteins, we performed molecular dynamics (MD) simulations with a coarse‐grained (CG) model. In MD simulations with the CG model for LARFH, we found that the molecules approached faster in the system where the mutant protein with positively charged amino acids was placed with the mutant protein with negatively charged amino acids than in the system containing two wild‐type protein molecules. In the system with the variants, the number of contact interfaces with the positive variant‐negative variant combination after 150 ns simulation is larger than that with the positive–positive variants combination or the negative–negative variants combination. Sulerythrin has two pairs of Fe2+ and Zn2+. Electronic structure calculation was performed around metal ions in sulerythrin. By electronic structure calculation for sulerythrin around metal ions, the electric charge and spin density were estimated. © 2012 Wiley Periodicals, Inc.
Client cloud Web service: reducing traffic consumption
Authors: Paik Jung Ha , Cho Kwantae , Jung Boo Geum , Lee Dong Hoon 
Published: June 2012

AbstractThe availability of the Web service has been exposed to several threats such as distributed denial‐of‐service attack, which is not an unfamiliar terminology anymore. Sustaining availability against various attacks becomes the critical issue for high‐profile Web sites. In this paper, we propose a novel architecture providing Web service among client, called client cloud Web service, by utilizing resources of clients to enhance the availability. Client cloud Web service can be easily integrated into the current Internet protocol suite by providing a transparent layer in the middle of Hypertext Transfer Protocol layer and Transmission Control Protocol/Internet Protocol layer. It is shown by simulations that the proposed architecture can efficiently reduce the traffic when both the size of Web items and the number of requests from clients increase. Copyright © 2012 John Wiley & Sons, Ltd.
More efficient CCA‐secure unidirectional proxy re‐encryption schemes without random oracles
Authors: Wang Hongbing , Cao Zhenfu 
Published: June 2012

ABSTRACTIn this paper, we present a more efficient chosen‐ciphertext secure proxy re‐encryption scheme in the standard model with less ciphertext size and without any strong unforgeable one‐time signature. Our scheme is unidirectional and single‐hop. The security of our scheme is under the reasonable complexity assumption—the decisional bilinear Diffie–Hellman assumption in bilinear groups. There are no proxy re‐encryption schemes achieving chosen‐ciphertext security in the standard model without a strong unforgeable one‐time signature in the literature. Copyright © 2012 John Wiley & Sons, Ltd.
Secure SIP authentication scheme supporting lawful interception
Authors: Pu Qiong , Wang Jian , Wu Shuhua 
Published: June 2012

ABSTRACTThe session initiation protocol (SIP) is the most widely used signaling protocol for creating, modifying, and terminating multimedia sessions in an Internet Protocol‐based telephony environment. Recently, Arshad et al. proposed an authentication scheme based on elliptic curve cryptosystems for SIP. In this paper, we first show that their scheme is vulnerable to the password‐guessing attack. Thereafter, we propose a new authentication and key agreement scheme for SIP, which is immune to the presented attacks. Our scheme achieves provable security and, yet, is efficient. Moreover, we also provide an extended scheme capable of protecting media stream's privacy even against SIP servers while supporting lawful interception, which is inevitably required for protecting the national security or for detecting the criminal evidence. Copyright © 2012 John Wiley & Sons, Ltd.
Research and implementation of M2M smart home and security system
Authors: Jiang Ting , Yang Ming , Zhang Yi 
Published: June 2012

AbstractOver recent years, the concept of Internet of Things has been put forward and undergone gradual progress. Machine to machine (M2M) technology, as the most prevalent application form of Internet of Things now, is widely used in various fields, among which smart home takes on tremendous market potential in virtue of its intimate relationship with human life. This paper endeavors to propose the smart home and security system, an M2M application system based on wireless networks, by combining wireless sensor network, mobile communication network, and the Internet together and briefly introduces the architecture, function, interface, identity addressing, and security mechanism of this system. Copyright © 2012 John Wiley & Sons, Ltd.
Threat‐oriented security framework in risk management using multiagent system
Authors: Bedi Punam , Gandotra Vandana , Singhal Archana , Narang Himanshi , Sharma Sumit 
Published: June 2012

SUMMARYPresent day sophisticated and innovative attacks have resulted in exponentially increasing security problems. This paper therefore presents a three‐phased threat‐oriented security model to meet the above security challenges as a part of proactive risk management. This model is based on a spiral process for software development because it is a risk driven approach and provides an incremental method for a progressively growing system with decreasing risk. Integration of threat management during the development process in the proposed work provides necessary security cover against both unforeseen and known threats. Identification of these threats has been made possible by fusion of a threat modeling process and research honeytokens in conjunction with a statistical model in the first phase. Necessary security measures to mitigate the above identified threats have been adopted in the second phase using multiagent system planning. Risk reduction as a result of adoption of countermeasures has been evaluated in the third phase using meta‐agents in association with fuzzy logic in a multiagent environment. The proposed proactive measures of this model have been demonstrated with a case study on ‘Online Banking’ to show its feasibility and has been implemented using Java Agent Development Environment, Apache Tomcat Server, with MySQL Server at the backend. Copyright © 2012 John Wiley & Sons, Ltd.
Targeting p90 Ribosomal S6 Kinase Eliminates Tumor-Initiating Cells by Inactivating Y-Box Binding Protein-1 in Triple-Negative Breast Cancers
Authors: Stratford Anna L. , Reipas Kristen , Hu Kaiji , Fotovati Abbas , Brough Rachel , Frankum Jessica , Takhar Mandeep , Watson Peter , Ashworth Alan , Lord Christopher J. , Lasham Annette , Print Cristin G. , Dunn Sandra E. 
Published: June 2012

AbstractY-box binding protein-1 (YB-1) is the first reported oncogenic transcription factor to induce the tumor-initiating cell (TIC) surface marker CD44 in triple-negative breast cancer (TNBC) cells. In order for CD44 to be induced, YB-1 must be phosphorylated at S102 by p90 ribosomal S6 kinase (RSK). We therefore questioned whether RSK might be a tractable molecular target to eliminate TICs. In support of this idea, injection of MDA-MB-231 cells expressing Flag-YB-1 into mice increased tumor growth as well as enhanced CD44 expression. Despite enrichment for TICs, these cells were sensitive to RSK inhibition when treated ex vivo with BI-D1870. Targeting RSK2 with small interfering RNA (siRNA) or small molecule RSK kinase inhibitors (SL0101 and BI-D1870) blocked TNBC monolayer cell growth by ∼100%. In a diverse panel of breast tumor cell line models RSK2 siRNA predominantly targeted models of TNBC. RSK2 inhibition decreased CD44 promoter activity, CD44 mRNA, protein expression, and mammosphere formation. CD44+ cells had higher P-RSKS221/227, P-YB-1S102, and mitotic activity relative to CD44− cells. Importantly, RSK2 inhibition specifically suppressed the growth of TICs and triggered cell death. Moreover, silencing RSK2 delayed tumor initiation in mice. In patients, RSK2 mRNA was associated with poor disease-free survival in a cohort of 244 women with breast cancer that had not received adjuvant treatment, and its expression was highest in the basal-like breast cancer subtype. Taking this further, we report that P-RSKS221/227 is present in primary TNBCs and correlates with P-YB-1S102 as well as CD44. In conclusion, RSK2 inhibition provides a novel therapeutic avenue for TNBC and holds the promise of eliminating TICs.
Recognition of peak oil
Authors: Campbell C.J. 
Published: June 2012

AbstractOil and gas have provided much of the energy to drive the Industrial Revolution over the past two centuries, but they are finite resources formed in the geological past, which means they are subject to depletion. The peak of world oil discovery in the 1960s must deliver a corresponding peak of production. The onset of the decline of this critical energy source will likely have far‐reaching social, economic, and political consequences. This turning point in history would be self‐evident but for lax reporting standards and ambiguous definitions. © 2012 John Wiley & Sons, Ltd.This article is categorized under:

Fossil Fuels > Economics and Policy
Fossil Fuels > Systems and Infrastructure
Applications of real number theorem proving in PVS
Authors: Gottliebsen Hanne , Hardy Ruth , Lightfoot Olga , Martin Ursula 
Published: June 2012

Abstract
Real number theorem proving has many uses, particularly for verification of safety critical systems and systems for which design errors may be costly. We discuss a chain of developments building on real number theorem proving in PVS. This leads from the verification of aspects of an air traffic control system, through work on the integration of computer algebra and automated theorem proving to a new tool, NRV, first presented here that builds on the capabilities of Maple and PVS to provide a verified and automatic analysis of Nichols plots. This automates a standard technique used by control engineers and greatly improves assurance compared with the traditional method of visual inspection of the Nichols plots.
Microsatellite Instability Is Associated With a Better Prognosis for Gastric Cancer Patients After Curative Surgery
Authors: Fang Wen‐Liang , Chang Shih‐Ching , Lan Yuan‐Tzu , Huang Kuo‐Hung , Chen Jen‐Hao , Lo Su‐Shun , Hsieh Mao‐Chih , Li Anna Fen‐Yau , Wu Chew‐Wun , Chiou Shih‐Hwa 
Published: June 2012

AbstractBackgroundMicrosatellite instability (MSI) is one of the leading mechanisms for the carcinogenesis of gastric cancer. Its prognostic value is controversial.MethodsBetween May 1988 and Oct 2003, a total of 214 gastric cancer patients undergoing curative surgery were enrolled, and their MSI statuses were classified as MSI‐H (high) or MSI‐L/S (low/stable). The clinicopathologic characteristics of MSI‐H and MSI‐L/S gastric cancers were compared.ResultsThe MSI‐H tumors accounted for 11.7 % (n = 25) of the 214 total gastric cancers. Although not statistically significant, the MSI‐H gastric cancers were more frequently located in the lower third of the stomach (64 % vs. 49.2 %) and were more often the intestinal type (72 % vs. 61.4 %) compared to the MSI‐L/S gastric cancers. The MSI‐H gastric cancers had a significantly better 5‐year overall survival (OS) rate (68 % vs. 47.6 %, p = 0.030) and a trend of a better 3‐year disease‐free survival rate (71.8 % vs. 55.2 %, p = 0.076) compared to the MSI‐L/S gastric cancers. A multivariate analysis revealed that pathologic TNM stage and MSI status were the independent prognostic factors for OS after curative surgery.ConclusionsCompared to MSI‐L/S tumors, MSI‐H tumors are associated with a better OS rate for gastric cancer patients after R0 resection.