bluuebunny/crossref_metadata_2025_split huggingface dataset:
Disulfiram is a DNA demethylating agent and inhibits prostate cancer cell growth
Authors: Lin Jianqing , Haffner Michael C. , Zhang Yonggang , Lee Byron H. , Brennen W. Nathaniel , Britton Justin , Kachhap Sushant K. , Shim Joong Sup , Liu Jun O. , Nelson William G. , Yegnasubramanian Srinivasan , Carducci Michael A. 
Published: August 2010

AbstractBACKGROUNDThe clinical success of the nucleoside analogs 5‐aza‐cytidine (5‐azaC) and 5‐aza‐2′deoxycytidine (5‐aza‐dC) as DNA methyltransferase (DNMT) inhibitors has spurred interest in the development of non‐nucleoside inhibitors with improved pharmacologic and safety profiles. Because DNMT catalysis features attack of cytosine bases by an enzyme thiol group, we tested whether disulfiram (DSF), a thiol‐reactive compound with known clinical safety, demonstrated DNMT inhibitory activity.METHODSInhibition of DNMT1 activity by DSF was assessed using methyltransferase activity assays with recombinant DNMT1. Next, prostate cancer cell lines were exposed to DSF and assessed for: i) reduction of global 5‐methyl cytosine (5meC) content using liquid chromatography/tandem mass spectrometry (LC‐MS/MS); ii) gene‐specific promoter demethylation by methylation‐specific PCR (MSP); and iii) gene‐reactivation by real‐time RT‐PCR. DSF was also tested for growth inhibition using prostate cancer cell lines propagated in vitro in cell culture and in vivo as xenografts in nude mice.RESULTSDisulfiram showed a dose‐dependent inhibition of DNMT1 activity on a hemimethylated DNA substrate. In prostate cancer cells in culture, DSF exposure led to reduction of global genomic 5meC content, increase in unmethylated APC and RARB gene promoters, and associated re‐expression of these genes, but did not significantly alter prostate‐specific antigen (PSA) expression. DSF significantly inhibited growth and clonogenic survival of prostate cancer cell lines in culture and showed a trend for reduced growth of prostate cancer xenografts.CONCLUSIONSDisulfiram is a non‐nucleoside DNMT1 inhibitor that can reduce global 5meC content, reactivate epigenetically silenced genes, and significantly inhibit growth in prostate cancer cell lines. Prostate 77:333–343, 2011. © 2010 Wiley‐Liss, Inc.
Measuring disorder in graphene with the G and D bands
Authors: Jorio Ado , Ferreira Erlon H. Martins , Moutinho Marcus V. O. , Stavale Fernando , Achete Carlos A. , Capaz Rodrigo B. 
Published: August 2010

AbstractHere we analyse the evolution of the disorder induced D‐band (∼1350 cm−1) and of the first‐order allowed G‐band (∼1584 cm−1) in the Raman spectra of ion bombarded graphene. By increasing the bombardment time, we increase the disorder and, consequently, decrease the average distance (LD) between defects. We describe how the intensity, full width at half maximum (FWHM) and integrated area vary for the D and G bands as a function of LD. Finally, we compare the evolution of the intensity ratio ID/IG and of the integrated area ratio AD/AG between the D and G bands as a method for quantifying disorder in graphene. For practical use and inter‐laboratorial comparison, the authors advise using the intensity ratio for a more suitable measure for analysing defect density.
A mollified ensemble Kalman filter
Authors: Bergemann Kay , Reich Sebastian 
Published: August 2010

AbstractIt is well recognized that discontinuous analysis increments of sequential data assimilation systems, such as ensemble Kalman filters, might lead to spurious high‐frequency adjustment processes in the model dynamics. Various methods have been devised to spread out the analysis increments continuously over a fixed time interval centred about the analysis time. Among these techniques are nudging and incremental analysis updates (IAU). Here we propose another alternative, which may be viewed as a hybrid of nudging and IAU and which arises naturally from a recently proposed continuous formulation of the ensemble Kalman analysis step. A new slow–fast extension of the popular Lorenz‐96 model is introduced to demonstrate the properties of the proposed mollified ensemble Kalman filter. Copyright © 2010 Royal Meteorological Society
Assessing atmospheric predictability on Mars using numerical weather prediction and data assimilation
Authors: Rogberg P. , Read P. L. , Lewis S. R. , Montabone L. 
Published: August 2010

AbstractThe intrinsic and practical predictability of the Martian atmosphere is determined by use of a comprehensive numerical circulation model and ensemble forecasting techniques. Initial conditions were derived for various seasons of the Martian climate from newly available assimilations of global observations of temperature and dust optical depth in the Martian atmosphere, obtained by the Thermal Emission Spectrometer (TES) instrument on the Mars Global Surveyor orbiter. A range of initial value forecasts were obtained and the growth rate of forecast errors measured against the assimilated re‐analysis were determined as a function of season during the period from the late Martian year 24 to early 27 (from May 1999 to August 2004). The intra‐ensemble growth rates confirm earlier stand‐alone model results, indicating that internal baroclinic transients lead to significant chaotic growth of model ‘error’ on time‐scales of 3–10 sols only during Northern Hemisphere autumn and winter seasons. At other seasons, ensembles retain coherence at least over several tens of sols. Imperfections in dust distribution and coupling with other aerosols can lead to large errors in the dust field when it evolves rapidly. Owing to the very short time‐scale on Mars, these errors can lead to rapid divergence of the entire ensemble from the observed atmospheric state. These results demonstrate the importance of even relatively small errors in the aerosol fields and so in the computed radiative balance of the Martian atmosphere for deterministic forecasts throughout the Martian year, including times at which baroclinic transients are inactive. Copyright © 2010 Royal Meteorological Society
Modeling of plastic scintillation composition of poly(methyl methacrylate)–naphthalene–POPOP
Authors: Irgibaeva Irina Smailovna , Barashkov Nikolay , Aldongarov Anuar , Mantel Artur , Barashkova Irina 
Published: August 2010

AbstractGeometry optimizations of monomers were carried out with the use of Becke's three‐parameter hybrid method with Lee, Yang, and Parr (B3LYP) gradient‐corrected correlation functional and the standard 6‐31G(d) basis set. UV–vis spectra of different naphthalene‐POPOP complexes using ZINDO/S method were calculated. In these complexes, poly(methyl methacrylate) effect on chromophores was neglected and chromophores were staked. Analyzing available experimental data and obtained theoretical results, the most probable complex structure is determined. Molecular model of POPOP and naphthalene dimer corresponds to this structure. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Theoretical assessment of new molecules for second‐order nonlinear optics
Authors: Labidi Sofiane Nouar , Kanoun Mohammed Benali , De Wergifosse Marc , Champagne Benoît 
Published: August 2010

AbstractThe polarizabilities and first hyperpolarizabilities of nine recently synthesized compounds have been calculated ab initio to assess the effects of basis sets, of electron correlation (at the MP2 level), of frequency dispersion, and of the solvent within the polarizable continuum model, as well as to address structure–property relationships. These calculations confirm that moderate‐size basis sets like 6‐31+G* or 6‐311+G* are enough to provide accurate estimates of the polarizabilities and first hyperpolarizabilities for these systems build from the combination of π‐conjugated linkers with donor/acceptor moieties. They describe the specific behavior of the hyper‐Rayleigh scattering (HRS) first hyperpolarizability and of its depolarization ratio as a function of the incident light frequency. Then, these calculations exemplify the large impact of including electron correlation and solvent effects on the first hyperpolarizabilities, and the crucial issue in view of optimizing the NLO compounds, that these effects are strongly system dependent. Finally, this theoretical investigation draws attention to the interplay between several second‐order nonlinear optical molecular responses: the norm of the first hyperpolarizability (β), the projection on the dipole moment (β//), which can be obtained from electric field–induced second‐harmonic generation measurements, and the HRS response (βHRS). © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Computed stabilities in metallofullerene series: Al@C82, Sc@C82, Y@C82, and La@C82
Authors: Slanina Zdeněk , Uhlík Filip , Lee Shyi‐Long , Adamowicz Ludwik , Akasaka Takeshi , Nagase Shigeru 
Published: August 2010

AbstractThis article reports computations for Al@C82, Sc@C82, Y@C82, and La@C82 based on encapsulation into the IPR (isolated pentagon rule) C2v C82 cage. Their structural and bonding features are also used for evaluations of the relative production yields, employing the encapsulation Gibbs‐energy terms and saturated metal pressures. The results can be well related to the ionization potentials of the free metal atoms and thus also rationalized. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Stability and protonation of multielectron systems: The concept of proton affinity. I. Vague limits
Authors: Kryachko Eugene S. 
Published: August 2010

AbstractThe present work is a kind of a “polyphonic” collection of thoughts about the relationship between the stability of multi‐electron systems and the protonation. The intricacy of the protonation sites and the protonated states that are absorbed into the concept of the proton affinity is discussed, particularly addressing its range of validity. This work can also be considered as an attempt to have a look “at different angles” at one of the most important molecular processes that occur in nature and that are reflected in our mirror of the perception of nature. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
How to solve the problem of dynamical correlation of electrons in the ground state helium atom?
Authors: Ignatiev V. D. 
Published: August 2010

AbstractIt is found that, for the ground state helium atom, a stationary wave function obtained from the stationary Shrödinger equation for one of the interacting electrons is much more physically meaningful than that from the equation for both electrons. Hamiltonian includes one‐electron Laplacian and operators of electron–nuclear attraction and electron–electron repulsion. Corresponding energy is equal to the first ionization potential. This approach recovers evident insufficiency of summation of potential energies accompanied by determination of kinetic energy from the virial relation. It appears that the kinetic energy must be determined independently. The kinetic energy of both electrons lowers due to inertia of the electron movement. It demands for a time‐resolved consideration of the electron movement in helium. The total energy cannot be minimized in one step, that is, by help of a single stationary wave function. It should be minimized with means of two wave functions in accord with experimental sequential ionization. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Polarizabilities of carbon nanotubes: Importance of the crystalline orbitals relaxation in presence of an electric field
Authors: Ehinon Daniel , Baraille Isabelle , Rérat Michel 
Published: August 2010

AbstractThe static polarizabilities of a series of zigzag single walled carbon nanotubes [(m, 0) with m ≠ 3n for m = 7–25] were computed by the coupled perturbed Kohn‐Sham (CPKS) coupled method recently implemented in the periodic CRYSTAL code. This method makes it possible to compute both the longitudinal and transverse polarizabilities with the same approach including the local field depolarization effects for the whole series of the investigated nanotubes. To quantify these effects, the unscreened longitudinal and transverse polarizabilities were also calculated within the linear response theory using the Sum Over States (SOS) method. Our results confirmed the inverse‐square dependence on the bandgap of the longitudinal polarizabilities which are found weakly affected by the crystalline orbital relaxation. On the other hand, the comparison between the screened (CPKS) and unscreened (Sum Over States) transverse polarizabilities permit to calibrate more precisely the classical correction of Benedict et al. (Phys Rev B, 1995, 52, 8541) which must be applied to include the local field effect at the SOS level. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Aromatic pathways in conjugated rings connected by single bonds
Authors: Taubert Stefan , Kaila Ville R. I. , Sundholm Dage 
Published: August 2010

AbstractMagnetically induced current densities and molecular structures for molecules consisting of two conjugated rings formally connected by a single bond have been studied at correlated ab initio and density functional theory levels. The molecular structures and magnetically induced current densities were calculated for the lowest singlet and triplet states of biphenyl, bicyclobutadiene, phenyl‐cyclobutadiene, and crosslinked phenol–imidazole, which is a model system for the crosslinked histidine–tyrosine found in heme–copper oxidases. Gauge‐origin independent current densities were obtained by using the gauge‐including magnetically induced current method. The lowest triplet states have a significantly shorter bond between the conjugated rings and generally a more planar structure when compared with the singlet ground state. The shorter bond distance between the conjugated rings indicates a π‐electron delocalization between the rings. Current‐density calculations show that the singlet states sustain ring currents mainly in the individual rings. The calculations also suggest that the shorter crosslink between the rings in the triplet states is accompanied with an increased current delocalization over the connected rings. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Theoretical study of solvent effect on the structure, first electronic excited state, and nonlinear optical properties of substituted stilbazolium cations
Authors: Inerbaev Talgat M. , Gu Feng Long , Mizuseki Hiroshi , Kawazoe Yoshiyuki 
Published: August 2010

AbstractMolecular structure, first excited state properties and charge distribution of a series of substituted stilbazolium cations in different media are theoretically investigated. First static hyperpolarizability (β0) of considered compounds is studied by both finite‐field and two‐state model methods. In contrast to the recent theoretical studies, in present contribution the mutually consistent description of solvent polarity dependence of β0 calculated by both employed approaches is achieved. It is shown that the ground‐to‐excited state intramolecular charge‐transfer is significantly affected by the solvent that provides the hyperpolarizability variation. Taking into account both solvent polarity and substituent effect the peculiarities of β0 behavior of stilbazolium derivatives are re‐examined. The effect of molecular geometry on the calculated electronic excitation properties is investigated. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
A null despreader for interference suppression in GPS
Authors: Hwang Suk‐seung , Shynk John J. 
Published: August 2010

AbstractThe Global Positioning System (GPS) utilizes low‐power spread‐spectrum signals and thus is vulnerable to various types of high‐power interference sources. It requires at least four satellites for estimating three‐dimensional user positions and the receiver clock bias. In this paper, we propose a blind adaptive GPS receiver that is based on a new despreader and the one‐stage constant modulus (CM) array. The despreader consists of a conventional GPS despreader and a so‐called null despreader, which together modify the received signal so that the CM array can extract the GPS signal of interest. The beamformer not only rejects jammers and extracts the GPS signal of interest without explicit direction‐of‐arrival (DOA) information of any of the signals but also it has a low computational complexity compared with conventional techniques, such as minimum‐variance distortionless‐response (MVDR) beamforming. As a conventional despreader can recover only one GPS signal, multiple despreaders are usually required for separating multiple GPS signals. We also explore an extension of the proposed null despreader to detect multiple GPS signals. Computer simulation examples are presented to illustrate the performance of the receiver for different types of jammer signals. Copyright © 2010 John Wiley & Sons, Ltd.
On the quality of broadcast services in vehicularad hocnetworks
Authors: Rossi Dario , Fracchia Roberta , Meo Michela 
Published: August 2010

AbstractWe investigate the broadcast problem in suburban and highway inter‐vehicular networks, aiming at providing a definitive comparison of two antipodean broadcast algorithm classes: the first one makes use of someinstantaneous informationlocally available at the vehicles (such as vehicle position and speed), while the second one relies onlong‐term knowledgegained through a beaconing procedure. Using a realistic microscopic model to represent the vehicular traffic flow, we investigate the performance of the above broadcast algorithm classes by simulation, considering different classes of network services (e.g., Critical, Normal, and Low‐priority). In order to explore a very large algorithmic design space, we devise a convex hull framework that allows us to effectively compare and compactly present the boundaries of the solution space for each algorithm class. By the use of such framework, we show that the beaconless performance encompasses a wider spectrum with respect to the beaconed one, with lower complexity and overhead. Copyright © 2010 John Wiley & Sons, Ltd.
From mobile phones to responsible devices
Authors: Traynor Patrick , Amrutkar Chaitrali , Rao Vikhyath , Jaeger Trent , McDaniel Patrick , La Porta Thomas 
Published: August 2010

AbstractMobile phones have evolved from simple voice terminals into highly‐capable, general‐purpose computing platforms. While people are becoming increasingly more dependent on such devices to perform sensitive operations, protect secret data, and be available for emergency use, it is clear that phone operating systems are not ready to become mission‐critical systems. Through a pair of vulnerabilities and a simulated attack on a cellular network, we demonstrate that there are a myriad of unmanaged mechanisms on mobile phones, and that control of these mechanisms is vital to achieving reliable use. Through such vectors, mobile phones introduce a variety of new threats to their own applications and the telecommunications infrastructure itself. In this paper, we examine the requirements for providing effective mediation and access control for mobile phones. We then discuss the convergence of cellular networks with the Internet and its impact on effective resource management and quality of service. Based on these results, we argue for user devices that enable predictable behavior in a network—where their trusted computing bases can protect key applications and create predictable network impact. Copyright © 2010 John Wiley & Sons, Ltd.
A WLAN security management framework based on formal spatio‐temporal RBAC model
Authors: Bera P. , Ghosh S. K. , Dasgupta Pallab 
Published: August 2010

AbstractIn today's organizations, the large scale deployment of wireless networks has opened up new directions in network security management. The organizational security policies aim at protecting the network resources from unauthorized accesses in the wireless local area networks (WLAN). In WLAN security policy management, the standard IP‐based access control mechanisms are not sufficient due to dynamic changes in network topology and access control states. The role‐based access control (RBAC) models may be appropriate to strengthen the security perimeter over the network resources. However, formalizing the dynamic binding of the access policies to the roles, depending on various control states, is a major challenge. In this paper, we propose a WLAN security policy management framework based on a formalspatio‐temporal RBAC(STRBAC) model. The present work primarily focuses on dynamic computation of security policies based on various control states, its formal representation using STRBAC model, and security property verification of the proposed STRBAC model. The proposed policy management framework logically partitions the WLAN topology into various security policy zones. The framework includes aCentral Authentication & Role Server(CARS) which authenticates the users (nodes) and access points (AP) and also assigns appropriate roles to the users; aGlobal Policy Server(GPS) that dynamically computes the global security policy and policy configurations for different policy zones based on local user‐role and control state information; a distributed policy zone control architecture. Each policy zone consists of aPolicy Zone Controller(WPZCon) which dynamically computes the low‐level access configurations. Finally, a SAT based verification procedure has been presented for verifying the security properties of the proposed STRBAC model. Copyright © 2010 John Wiley & Sons, Ltd.
A comparison of multiple imputation and fully augmented weighted estimators for Cox regression with missing covariates
Authors: Qi Lihong , Wang Ying‐Fang , He Yulei 
Published: August 2010

AbstractSeveral approaches exist for handling missing covariates in the Cox proportional hazards model. The multiple imputation (MI) is relatively easy to implement with various software available and results in consistent estimates if the imputation model is correct. On the other hand, the fully augmented weighted estimators (FAWEs) recover a substantial proportion of the efficiency and have the doubly robust property. In this paper, we compare the FAWEs and the MI through a comprehensive simulation study. For the MI, we consider the multiple imputation by chained equation and focus on two imputation methods: Bayesian linear regression imputation and predictive mean matching. Simulation results show that the imputation methods can be rather sensitive to model misspecification and may have large bias when the censoring time depends on the missing covariates. In contrast, the FAWEs allow the censoring time to depend on the missing covariates and are remarkably robust as long as getting either the conditional expectations or the selection probability correct due to the doubly robust property. The comparison suggests that the FAWEs show the potential for being a competitive and attractive tool for tackling the analysis of survival data with missing covariates. Copyright © 2010 John Wiley & Sons, Ltd.