bluuebunny/crossref_metadata_2025 huggingface dataset:
Ion Association Trends in Alkaline Earth‐Metal Tetraphenylborates
Authors: Verma Abhilasha , Guino‐o Marites , Gillett‐Kunnath Miriam , Teng Weijie , Ruhlandt‐Senge Karin
Published: April 2009

A family of cationic heavy alkaline earth‐metal complexes based on the weakly coordinating tetraphenylborate anion [BPh4]– provides unique insight into ion association trends within this family of compounds. The compounds were prepared by protonolysis of the respective alkaline earth‐metal bis[bis(trimethylsilyl)]amides M[N(SiMe3)2]2(thf)2 (M = Ca, Sr, Ba) with ammonium tetraphenylborates [R3NH][BPh4] (R = Me, Et) in various stoichiometric ratios, resulting in the separated ions [M(donor)n][BPh4]2 (M = Ca, Sr, Ba; n = number of donors). All compounds but [Ba(hmpa)6][BPh4]2 (3c) were characterized using single‐crystal X‐ray diffraction, 1H and 13C NMR, IR spectroscopy and melting point.
Aspects of the Coordination Chemistry of 1,1′‐Bis(benzothiazol‐2‐ylthio)ferrocene
Authors: Siemeling Ulrich , Girod Alexander , Rother Dag , Bruhn Clemens
Published: April 2009

1,1′‐Bis(benzothiazol‐2‐ylthio)ferrocene (1) acts as a bridging bidentate N,N‐ligand and affords coordination polymers with a range of CuI, AgI, CuII, ZnII and HgII salts. The crystal structures of [Ag(CF3SO3)(μ‐1)]n, [CuCl2(μ‐1)]n, [ZnCl2(μ‐1)]n and [HgBr2(μ‐1)]n have been determined. The silver atom exhibits a weak contact to a cyclopentadienyl π‐system in addition to its trigonal‐planar coordination. The copper atom is in a square‐planar coordination environment, whereas the coordination of zinc and mercury is best described as distorted tetrahedral in the corresponding complexes.
Neuropathological study of skeletal muscle, heart, liver, and brain in a neonatal form of glycogen storage disease type IV associated with a new mutation in GBE1 gene
Authors: Lamperti C. , Salani S. , Lucchiari S. , Bordoni A. , Ripolone M. , Fagiolari G. , Fruguglietti M. E. , Crugnola V. , Colombo C. , Cappellini A. , Prelle A. , Bresolin N. , Comi G. P. , Moggio M.
Published: April 2009

Glycogen storage disease type IV (GSD IV, or Andersen disease) is an autosomal recessive disorder due to the deficiency of 1,4‐α‐glucan branching enzyme (or glycogen branching enzyme, GBE1), resulting in an accumulation of amylopectin‐like polysaccharide in muscle, liver, heart and central and peripheral nervous system. Typically, the presentation is in childhood with liver involvement up to cirrhosis. The neuromuscular form varies in onset (congenital, perinatal, juvenile and adult) and in severity. Congenital cases are rare, and fewer than 20 cases have been described and genetically determined so far. This form is characterized by polyhydramnios, neonatal hypotonia, and neuronal involvement; hepatopathy is uncommon, and the babies usually die between 4 weeks and 4 months of age. We report the case of an infant who presented severe hypotonia, dilatative cardiomyopathy, mild hepatopathy, and brain lateral ventricle haemorrhage, features consistent with the congenital form of GSD IV. He died at one month of life of cardiorespiratory failure. Muscle biopsy and heart and liver autoptic specimens showed many vacuoles filled with PAS‐positive diastase‐resistant materials. Electron‐microscopic analysis showed mainly polyglucosan accumulations in all the tissues examined. Postmortem examination showed the presence of vacuolated neurons containing this abnormal polysaccharide. GBE1 biochemical activity was virtually absent in muscle and fibroblasts, and totally lacking in liver and heart as well as glycogen synthase activity. GBE1 gene sequence analysis revealed a novel homozygous nonsense mutation, p.E152X, in exon 4, correlating with the lack of enzyme activity and with the severe neonatal involvement. Our findings contribute to increasing the spectrum of mutation associated with congenital GSD IV.
A representation formula for the voltage perturbations caused by diametrically small conductivity inhomogeneities. Proof of uniform validity
Authors: Nguyen Hoai-Minh , Vogelius Michael S.
Published: April 2009

We revisit the asymptotic formulas originally derived in [D.J. Cedio-Fengya, S. Moskow, M.S. Vogelius, Identification of conductivity imperfections of small diameter by boundary measurements. Continuous dependence and computational reconstruction, Inverse Problems 14 (1998) 553–595; A. Friedman, M. Vogelius, Identification of small inhomogeneities of extreme conductivity by boundary measurements: A theorem on continuous dependence, Arch. Ration. Mech. Anal. 105 (1989) 299–326]. These formulas concern the perturbation in the voltage potential caused by the presence of diametrically small conductivity inhomogeneities. We significantly extend the validity of the previously derived formulas, by showing that they are asymptotically correct, uniformly with respect to the conductivity of the inhomogeneities. We also extend the earlier formulas by allowing the conductivities of the inhomogeneities to be completely arbitrary

L^{\infty }

, positive definite, symmetric matrix-valued functions. We briefly discuss the relevance of the uniform asymptotic validity, and the admission of arbitrary anisotropically conducting inhomogeneities, as far as applications of the perturbation formulas to “approximate cloaking” are concerned.
The RNA aptamer disrupts protein–protein interaction between β‐catenin and nuclear factor‐κB p50 and regulates the expression of C‐reactive protein
Authors: Choi Yong Seok , Hur Jung , Lee Hee Kyu , Jeong Sunjoo
Published: April 2009

MINT‐7023862: beta catenin (uniprotkb:P35222) binds (MI:0407) to NF‐kappa‐B p50 (uniprotkb:P19838) by pull down (MI:0096)
Automatic recognition of type III solar radio bursts: Automated Radio Burst Identification System method and first observations
Authors: Lobzin Vasili V. , Cairns Iver H. , Robinson Peter A. , Steward Graham , Patterson Garth
Published: April 2009

Because of the rapidly increasing role of technology, including complicated electronic systems, spacecraft, etc., modern society has become more vulnerable to a set of extraterrestrial influences (space weather) and requires continuous observation and forecasts of space weather. The major space weather events like solar flares and coronal mass ejections are usually accompanied by solar radio bursts, which can be used for a real‐time space weather forecast. Coronal type III radio bursts are produced near the local electron plasma frequency and near its harmonic by fast electrons ejected from the solar active regions and moving through the corona and solar wind. These bursts have dynamic spectra with frequency rapidly falling with time, the typical duration of the coronal burst being about 1–3 s. This paper presents a new method developed to detect coronal type III bursts automatically and its implementation in a new Automated Radio Burst Identification System. The central idea of the implementation is to use the Radon transform for more objective detection of the bursts as approximately straight lines in dynamic spectra. Preliminary tests of the method with the use of the spectra obtained during 13 days show that the performance of the current implementation is quite high, ∼84%, while no false positives are observed and 23 events not listed previously are found. Prospects for improvements are discussed. The first automatically detected coronal type III radio bursts are presented.
The Scalable Reasoning System: Lightweight Visualization for Distributed Analytics
Authors: Pike William , Bruce Joe , Baddeley Bob , Best Daniel , Franklin Lyndsey , May Richard , Rice Douglas , Riensche Rick , Younkin Katarina
Published: April 2009

A central challenge in visual analytics is the creation of accessible, widely distributable analysis applications that bring the benefits of visual discovery to as broad a user base as possible. Moreover, to support the role of visualization in the knowledge creation process, it is advantageous to allow users to describe the reasoning strategies they employ while interacting with analytic environments. We introduce an application suite called the scalable reasoning system (SRS), which provides web-based and mobile interfaces for visual analysis. The service-oriented analytic framework that underlies SRS provides a platform for deploying pervasive visual analytic environments across an enterprise. SRS represents a ‘lightweight’ approach to visual analytics whereby thin client analytic applications can be rapidly deployed in a platform-agnostic fashion. Client applications support multiple coordinated views while giving analysts the ability to record evidence, assumptions, hypotheses and other reasoning artifacts. We describe the capabilities of SRS in the context of a real-world deployment at a regional law enforcement organization.
Solar and wind energy potential in GCC countries and some related projects
Authors: Alnaser W. E. , Alnaser N. W.
Published: April 2009

The paper highlights the solar and wind energy potentials in the Gulf Cooperation Council (GCC) countries. The potential projects in each GCC country are also highlighted herein. We are expecting that the amount of new solar and wind electricity by 2015 in these countries may reach 5000MW distributed as follows: 1000MW in Bahrain, Qatar, 3500MW solar electricity, UAE: 400MW, and Kuwait and Oman: few MW. The paper also proposes a mechanism to accelerate the renewable energy utility in these countries.
Toward black-box-type full- and reduced-dimensional variational (ro)vibrational computations
Authors: Mátyus Edit , Czakó Gábor , Császár Attila G.
Published: April 2009

A black-box-type algorithm is presented for the variational computation of energy levels and wave functions using a (ro)vibrational Hamiltonian expressed in an arbitrarily chosen body-fixed frame and in any set of internal coordinates of full or reduced vibrational dimensionality. To make the required numerical work feasible, matrix representation of the operators is constructed using a discrete variable representation (DVR). The favorable properties of DVR are exploited in the straightforward and numerically exact inclusion of any representation of the potential and the kinetic energy including the G matrix and the extrapotential term. In this algorithm there is no need for an a priori analytic derivation of the kinetic energy operator, as all of its matrix elements at each grid point are computed numerically either in a full- or a reduced-dimensional model. Due to the simple and straightforward definition of reduced-dimensional models within this approach, a fully anharmonic variational treatment of large, otherwise intractable molecular systems becomes available. In the computer code based on the above algorithm, there is no inherent limitation for the maximally coupled number of vibrational degrees of freedom. However, in practice current personal computers allow the treatment of about nine fully coupled vibrational dimensions. Computation of vibrational band origins of full and reduced dimensions showing the advantages and limitations of the algorithm and the related computer code are presented for the water, ammonia, and methane molecules.
Modeling semiconductor nanostructures thermal properties: The dispersion role
Authors: Terris Damian , Joulain Karl , Lemonnier Denis , Lacroix David
Published: April 2009

We study heat transport in semiconductor nanostructures by solving the Boltzmann transport equation by means of the discrete ordinate method. Relaxation time and phase and group velocity spectral dependencies are taken into account. The Holland model of phonon relaxation time is revisited and recalculated from dispersion relations (taken in literature) in order to match bulk silicon and germanium values. This improved model is then used to predict silicon nanowire and nanofilm thermal properties in both ballistic and mesoscopic regimes.
Microwave-assisted switching of NiFe magnetic microstructures
Authors: Laval M. , Bonnefois J. J. , Bobo J. F. , Issac F. , Boust F.
Published: April 2009

We have calculated by either macrospin analytical method or micromagnetic numerical solving the microwave-assisted switching of a small rectangular platelet as a function of the amplitude and the frequency of a microwave excitation field. The spectral analysis of this phenomenon reveals that microwave-assisted switching is optimal for a rf slightly lower than the linear magnetic resonance frequency measured at low level. Similar experimental results, obtained on 100 μm scale NiFe structures, reveal the same tendency. Switching time for such a process was obtained from calculations that show that subnanosecond switching times require combinations of large dc and rf magnetic fields.
Process parameters and their relations for the dielectrophoretic assembly of carbon nanotubes
Authors: An Libao , Friedrich Craig R.
Published: April 2009

The selection of process parameters, which include the concentration of the carbon nanotube (CNT) suspension, the magnitude of the applied voltage, and the duration of the electric field, is significant in the assembly of a small number of CNTs across an electrode gap by dielectrophoresis (DEP). This paper investigates by simulation and experimentation these parameter relations. The simulation is based on the effective dipole moment method and considers the DEP force and viscous force on the CNT by the liquid medium. The method can be used to predict the assembly of a CNT originally located at any position within the electric field. The results demonstrate that the assembly time depends on the distance between the CNT and the electrode gap, as well as the magnitude of the applied voltage. Experiments confirm assembly times after recognizing the differences between the simulation and the experimental conditions. The results can help analyze the assembly of CNTs between electric conductors and help select DEP process parameters.
Single particle dynamics of water confined in a hydrophobically modified MCM-41-S nanoporous matrix
Authors: Faraone Antonio , Liu Kao-Hsiang , Mou Chung-Yuan , Zhang Yang , Chen Sow-Hsin
Published: April 2009

The single particle dynamics of water confined in a hydrophobically modified MCM-41-S sample has been studied using three high resolution quasielastic neutron scattering spectrometers in the temperature range from 300 to 210 K. A careful modeling of the dynamics allowed us to obtain good agreement among the results obtained with the three instruments, which have very different energy resolutions. The picture arising from the data is that, because of the heterogenous environment experienced by the water molecules, the dynamics show a broad distribution of relaxation times. However, the Fickian diffusive behavior is retained. In the investigated temperature range we found no evidence of the dynamic crossover, from a non-Arrhenius to an Arrhenius behavior, which was detected for water confined in hydrophilic MCM-41-S. This finding is in agreement with what was reported by Chu et al. [Phys. Rev. E 76, 021505 (2007)] for water confined in other hydrophobic confining media that the dynamic crossover takes place at a much lower temperature. The results reported in the paper help clarify the role that the chemical interaction between the water molecules and the walls of the confining host plays in determining the characteristics of the water dynamics, as compared to purely geometric constraints such as the size and shape of the pores.
The mean activity coefficients of 2:2 electrolyte solutions: An integral equation study of the restricted primitive model
Authors: Chung Ting-Horng , Lee Lloyd L.
Published: April 2009

We apply the closure theory ZSEP (self-consistent zero-separation based closures) developed earlier to the restricted primitive model (RPM) of 2:2 electrolytes in order to (i) obtain the activity coefficient information via the direct formula for chemical potentials [L. L. Lee, J. Chem. Phys. 97, 8606 (1992)] and (ii) test the performance of this flexible ZSEP closure at high-coupling strengths (i.e., high valency and low temperatures) for cases of 2:2 electrolytes where other closure schemes have encountered difficulties [e.g., the hypernetted chain (HNC) equation]. In particular, we shall remedy the shortcomings of the HNC theory at low concentrations (from 0.001M to 0.2M). The ZSEP closure is found to perform well at coupling strengths β′=|z1z2|e2/(εmkTd) approaching ∼10 where some other closure theories cease to give good results. In addition, by applying the direct chemical potential formula, we demonstrate numerically that, in the RPM cases examined, the logarithm of the mean activity coefficients of electrolytes are closely approximated by the electrostatic internal energy, an easily accessible quantity, a fact that shall afford ready access to the chemical potentials for phase equilibrium and electrochemical calculations on electrolytic systems.
Spectroscopic measurements of temperature and plasma impurity concentration during magnetic reconnection at the Swarthmore Spheromak Experiment
Authors: Chaplin V. H. , Brown M. R. , Cohen D. H. , Gray T. , Cothran C. D.
Published: April 2009

Electron temperature measurements during counterhelicity spheromak merging studies at the Swarthmore Spheromak Experiment (SSX) [M. R. Brown, Phys. Plasmas 6, 1717 (1999)] are presented. VUV monochromator measurements of impurity emission lines are compared with model spectra produced by the non-LTE excitation kinematics code PRISMSPECT [J. J. MacFarlane et al., in Proceedings of the Third Conference on Inertial Fusion Science and Applications (2004)] to yield the electron temperature in the plasma with 1 μs time resolution. Average Te is seen to increase from 12 to 19 eV during spheromak merging. Average C III ion temperature, measured with a new ion Doppler spectrometer (IDS) [C. D. Cothran et al., Rev. Sci. Instrum. 77, 063504 (2006)], likewise rises during spheromak merging, peaking at ∼22 eV, but a similar increase in Ti is seen during single spheromak discharges with no merging. The VUV emission line measurements are also used to constrain the concentrations of various impurities in the SSX plasma, which are dominated by carbon, but include some oxygen and nitrogen. A burst of soft x-ray emission is seen during reconnection with a new four-channel detector (SXR). There is evidence for spectral changes in the soft x-ray emission as reconnection progresses, although our single-temperature equilibrium spectral models are not able to provide adequate fits to all the SXR data.
Higher dimensional integrable mappings derived from coupled discrete nonlinear Schrödinger equations
Authors: Sahadevan R. , Rajakumar S.
Published: April 2009

A systematic investigation to derive higher dimensional coupled autonomous integrable mappings from scalar and coupled discrete nonlinear Schördinger equations is presented. The integrability (in the sense of Liouville) of the obtained higher dimensional mappings is ensured by showing that each of them is symplectic and possesses sufficient number of integrals of motion.
Study of ultraintense laser propagation in overdense plasmas for fast ignition
Authors: Lei A. L. , Tanaka K. A. , Kodama R. , Adumi K. , Habara H. , Kitagawa Y. , Kondo K. , Matsuoka T. , Tanimoto T. , Yabuuchi T. , Mima K. , Nagai K. , Nagatomo H. , Norimatsu T. , Sawai K. , Suzuki K. , Yu Wei , Xu Han , Yang X. Q. , Cao L. H. , Cai H. B. , Sentoku Y. , Pukhov A. , Kumar R. , Snavely R. , Freeman R. , Yu Min , Zheng J.
Published: April 2009

Laser plasma interactions in a relativistic regime relevant to the fast ignition in inertial confinement fusion have been investigated. Ultraintense laser propagation in preformed plasmas and hot electron generation are studied. The experiments are performed using a 100 TW 0.6 ps laser and a 20 TW 0.6 ps laser synchronized by a long pulse laser. In the study, a self-focused ultraintense laser beam propagates along its axis into an overdense plasma with peak density 1022/cm3. Channel formation in the plasma is observed. The laser transmission in the overdense plasma depends on the position of its focus and can take place in plasmas with peak densities as high as 5×1022/cm3. The hot electron beams produced by the laser-plasma interaction have a divergence angle of ∼30°, which is smaller than that from laser-solid interactions. For deeper penetration of the laser light into the plasma, the use of multiple short pulse lasers is proposed. The latter scheme is investigated using particle-in-cell simulation. It is found that when the pulse duration and the interval between the pulses are appropriate, the laser pulse train can channel into the plasma deeper than a single longer pulse laser of similar peak intensity and total energy.
Superdiffusive-like motion of colloidal nanorods
Authors: Campos Daniel , Méndez Vicenç
Published: April 2009

In recent experiments, the temporal average C(t) of the mean square displacement for nanorods moving through a chemical monolayer was explored. The results showed a scaling C(t)∼t1.6, which suggest the existence of superdiffusive motion for these particles. In this paper, we interpret these results by means of a continuous-time random walk (CTRW) model from which we can reproduce the exponent 1.6 and the curve C(t) versus time found in the experiments. We show that the behavior observed arises as a consequence of the superposition of different transport mechanisms: directional propulsion plus translational and rotational diffusion. Our model reveals that this superdiffusive-like scaling may also be found in other systems as in chemotactic biological motion, provided that the characteristic times for translational and rotational diffusions are very different.
Detailed analysis of bathocuproine layer for organic solar cells based on copper phthalocyanine and C60
Authors: Huang Jiang , Yu Junsheng , Lin Hui , Jiang Yadong
Published: April 2009

The electrical characteristics of double heterojunction organic solar cells with various thicknesses of bathocuproine (BCP) as an exciton-blocking layer (EBL) were studied. A theoretical analysis using optical transfer matrix theory was carried out to obtain insight into how the EBL influences light-absorbing and exciton-transporting properties in the organic layers. The results showed that by employing an 8–10 nm BCP layer exciton density was increased by 46%. By using an improved equivalent circuit model, photovoltaic characteristics were parametrized and modeled, which revealed that the thin BCP layer <10 nm did not affect the charge collection process. The mechanism of metallic cathode influence on solar cells was also discussed.
Size dependent optical band gap of ternary I-III-VI2 semiconductor nanocrystals
Authors: Omata Takahisa , Nose Katsuhiro , Otsuka-Yao-Matsuo Shinya
Published: April 2009

The size dependent optical band gap of the less-toxic ternary I-III-VI2 chalcopyrite-type semiconductor quantum dots (QDs), CuInS2, CuInSe2, CuGaS2, CuGaSe2, AgInSe2, AgGaS2, and AgGaSe2, were evaluated using the finite-depth-well effective mass approximation calculation. From the comparison of the calculation result with the experimental values for the CuInS2 case, it was shown that the calculation was highly valid to predict the size dependent optical gap of the ternary semiconductor QDs. The optical band gap of the above seven I-III-VI2 QDs covers a wide wavelength range from the near-infrared to ultraviolet. It has been shown that the I-III-VI2 semiconductor QDs have a significant potential as alternatives to the highly toxic cadmium-containing II-VI semiconductor QDs and they are applicable to the wide range of light emitting devices and solar cells.
Effect of wall perturbations on the receptivity of a hypersonic boundary layer
Authors: Wang Xiaowen , Zhong Xiaolin
Published: April 2009

The receptivity of a Mach 5.92 flat plate boundary layer to periodic two-dimensional wall perturbations is studied by numerical simulations and linear stability theory (LST). Free stream flow conditions are the same as the leading edge receptivity experiment of Maslov et al., J. Fluid Mech. 426, 73 (2001). Steady base flow is simulated by solving compressible Navier–Stokes equations with a combination of a fifth-order shock-fitting method and a second-order total variation diminishing scheme. The accuracy of the steady base flow is validated by comparisons with the experimental measurements of Maslov et al. and self-similar boundary-layer solution. In receptivity simulations, streamwise velocity perturbation, blowing suction, and temperature perturbation are introduced to the steady base flow with a forcing slot on flat plate. A model of wall perturbation is proposed based on physical properties of the electric pulse generator used in the experiment of Maslov et al. Stability characteristics of boundary-layer waves are identified and evaluated by comparing the results of LST and numerical simulation. Numerical simulation results show that all three types of wall perturbations eventually result in the same type of instability wave (mode S) in the boundary layer, which indicates that receptivity mechanism of the hypersonic boundary layer to wall perturbation is independent of specific perturbation type. On the other hand, the hypersonic boundary layer is found to be most sensitive to blowing-suction and least sensitive to temperature perturbation.
An “optimal” spawning algorithm for adaptive basis set expansion in nonadiabatic dynamics
Authors: Yang Sandy , Coe Joshua D. , Kaduk Benjamin , Martínez Todd J.
Published: April 2009

The full multiple spawning (FMS) method has been developed to simulate quantum dynamics in the multistate electronic problem. In FMS, the nuclear wave function is represented in a basis of coupled, frozen Gaussians, and a “spawning” procedure prescribes a means of adaptively increasing the size of this basis in order to capture population transfer between electronic states. Herein we detail a new algorithm for specifying the initial conditions of newly spawned basis functions that minimizes the number of spawned basis functions needed for convergence. “Optimally” spawned basis functions are placed to maximize the coupling between parent and child trajectories at the point of spawning. The method is tested with a two-state, one-mode avoided crossing model and a two-state, two-mode conical intersection model.
Electrical explosion of metals in fast-rising megagauss magnetic fields
Authors: Chaikovsky S. A. , Oreshkin V. I. , Mesyats G. A. , Ratakhin N. A. , Datsko I. M. , Kablambaev B. A.
Published: April 2009

A criterion for the surface explosion of metal conductors in strong magnetic fields with the magnetic induction rising at rates over 4×1013 G/s has been obtained for a current skinning mode: the explosion occurs as the magnetic energy density at the metal surface becomes as high as a factor of 1.5–2 of the sublimation energy density for the metal under normal conditions.
Structure of polyamidoamide dendrimers up to limiting generations: A mesoscale description
Authors: Maiti Prabal K. , Li Youyong , Cagin Tahir , Goddard William A.
Published: April 2009

The polyamidoamide (PAMAM) class of dendrimers was one of the first dendrimers synthesized by Tomalia and co-workers at Dow. Since its discovery the PAMAMs have stimulated many discussions on the structure and dynamics of such hyperbranched polymers. Many questions remain open because the huge conformation disorder combined with very similar local symmetries have made it difficult to characterize experimentally at the atomistic level the structure and dynamics of PAMAM dendrimers. The higher generation dendrimers have also been difficult to characterize computationally because of the large size (294852 atoms for generation 11) and the huge number of conformations. To help provide a practical means of atomistic computational studies, we have developed an atomistically informed coarse-grained description for the PAMAM dendrimer. We find that a two-bead per monomer representation retains the accuracy of atomistic simulations for predicting size and conformational complexity, while reducing the degrees of freedom by tenfold. This mesoscale description has allowed us to study the structural properties of PAMAM dendrimer up to generation 11 for time scale of up to several nanoseconds. The gross properties such as the radius of gyration compare very well with those from full atomistic simulation and with available small angle x-ray experiment and small angle neutron scattering data. The radial monomer density shows very similar behavior with those obtained from the fully atomistic simulation. Our approach to deriving the coarse-grain model is general and straightforward to apply to other classes of dendrimers.
Molecular dynamics simulation of amphiphilic molecules in solution: Micelle formation and dynamic coexistence
Authors: Fujiwara Susumu , Itoh Takashi , Hashimoto Masato , Horiuchi Ritoku
Published: April 2009

The micelle formation and the dynamic coexistence in amphiphilic solution are investigated by molecular dynamics simulation of coarse-grained rigid amphiphilic molecules with explicit solvent molecules. Our simulations show that three kinds of isolated micelles (disk, cylindrical, and spherical micelles) are observed at a lower temperature by quenching from a random configuration of amphiphilic molecules in solution at a higher temperature. The micellar shape changes from a disk into a cylinder, and then into a sphere as the hydrophilic interaction increases whereas it is not so sensitive to the variation of the hydrophobic interaction. This fact indicates that the hydrophilic interaction plays an important role in determining the micellar shape in the range of the interaction parameters used. It is also found that in a certain interaction parameter range, two kinds of micellar shapes coexist dynamically. From the detailed analyses of the dynamic coexistence, it is ascertained that the dynamic coexistence of a cylindrical micelle and a spherical micelle accompanies the coalescence and fragmentation of micelles while that of a disk micelle and a cylindrical micelle does not, but exhibits the continuous change between them.
Calculation of resonant interatomic Coulombic decay widths of inner-valence-excited states delocalized due to inversion symmetry
Authors: Kopelke S. , Gokhberg K. , Cederbaum L. S. , Averbukh V.
Published: April 2009

Inner-valence-excited states of clusters can decay by electron emission via several of mechanisms, the leading ones being intra-atomic autoionization and resonant interatomic Coulombic decay. Recently, we have derived the Wigner–Weisskopf theory for the calculation of the decay widths of the inner-valence excitations [J. Chem. Phys. 124, 144315 (2006)]. While the new method has been successful in producing the decay rates of heteronuclear diatomic clusters, it cannot be applied to systems possessing inversion symmetry, e.g., to homonuclear diatoms, due to delocalization of the molecular orbitals involved in the decay processes. In the present work, we show that the Wigner–Weisskopf theory of the decay of inner-valence-excited states can be generalized to systems with inversion symmetry using a technique of adapted final states [J. Chem. Phys. 125, 094107 (2006)]. The same technique can be employed when going beyond the Wigner–Weisskopf theory. We consider the experimentally relevant case of competing resonant interatomic Coulombic decay and autoionization in neon dimer and calculate the rates of these processes for a series of inner-valence-excited states which has been measured by Aoto et al. [Phys. Rev. Lett. 97, 243401 (2006)].
Healing of oxygen vacancies on reduced surfaces of gold-doped ceria
Authors: Nolan Michael
Published: April 2009

As an oxidation-reduction catalyst, ceria can catalyze molecular oxidation and reduction. There has been a focus on understanding and enhancing the vacancy formation process to improve the oxidative power of ceria. However, it is important to also address healing of the surface vacancy. To investigate healing of oxygen vacancies in ceria, we study the interaction of atomic and molecular oxygen and NO2 with oxygen vacancies on gold-doped (110) and (100) surfaces using density functional theory, corrected for on-site Coulomb interactions (DFT+U). For atomic and molecular oxygen, adsorption at the reduced surface is favorable and results in an oxygen atom sitting in an oxygen lattice site, healing the oxygen vacancy. On undoped surfaces, O2 adsorbs as a peroxo (O22−) species. However, on the doped (110) surface a superoxo (O2−) species is present. When NO2 adsorbs (exothermically) at a divacancy surface, one oxygen of the molecule sits in the vacancy site and the N–O distances are elongated and an [NO2]− anion forms, similar to the undoped surface. Vacancy healing of ceria surfaces is favorable, even if vacancy formation is enhanced, justifying the current focus on improving the oxidative power of ceria. We briefly examine a catalytic cycle: the reaction of CO with adsorbed O2 on the undoped and doped surfaces, and find that the doped (110) surface facilitates CO oxidation.
Fast imaging of laser-blow-off plume: Lateral confinement in ambient environment
Authors: George Sony , Kumar Ajai , Singh R. K. , Nampoori V. P. N.
Published: April 2009

The dynamics of plasma plume, formed by the laser-blow-off of multicomponent LiF-C thin film under various ambient pressures ranging from high vacuum to argon pressure of 3 Torr, has been studied using fast imaging technique. In vacuum, the plume has ellipsoidal shape. With the increase in the ambient pressure, sharp plume boundary is developed showing a focusing-like (confinement in the lateral space) behavior in the front end, which persists for long times. At higher ambient pressure (>10−1 Torr), structures are developed in the plasma plume due to hydrodynamic instability/turbulences.
Time-resolved pump-probe experiments beyond the jitter limitations at FLASH
Authors: Azima A. , Düsterer S. , Radcliffe P. , Redlin H. , Stojanovic N. , Li W. , Schlarb H. , Feldhaus J. , Cubaynes D. , Meyer M. , Dardis J. , Hayden P. , Hough P. , Richardson V , Kennedy E. T. , Costello J. T.
Published: April 2009

Using a noninvasive, electro-optically based electron bunch arrival time measurement at FLASH (free electron laser in Hamburg) the temporal resolution of two-color pump-probe experiments has been significantly improved. The system determines the relative arrival time of the extended ultraviolet pulse of FLASH and an amplified Ti:sapphire femtosecond-laser pulse at the interaction region better than 90 fs rms. In a benchmarking pump-probe experiment using two-color above threshold ionization of noble gases, an enhancement in the timing resolution by a factor of 4 compared to the uncorrected data is obtained.
Origin of low threshold field emission from nitrogen-incorporated nanocrystalline diamond films
Authors: Ikeda Tomohiro , Teii Kungen
Published: April 2009

Highly conductive, nitrogen-incorporated nanocrystalline diamond films with quasimetallic character emit electrons at low turn-on fields (∼3 V μm−1). These films exhibit stronger delocalization of carriers, indicative of smaller energy separation between the defect bands in the band gap. We show that the emission level derived from the measured emission characteristic and electron affinity shifts upward (up to a few eV) with increasing the film conductivity, thereby decreasing the effective potential barrier height for the emission. This is attributed to higher probabilities of electron injection into upper defect levels during the transport process, originating from internal band bending and increasing band continuity.
Eternity or Infinity? Badiou's Point
Authors: MacCannell Juliet Flower
Published: April 2009

I argue for a psychoanalytic approach to spatial questions. I then examine whether the topological (philosophical and mathematical) work of Alain Badiou is compatible with such an approach. French psychoanalyst Jacques Lacan, whom Badiou cites, also deployed topology, but I argue that Lacan's use of topology is fundamentally antithetical to Badiou's. As illustration, I analyze Badiou's treatment of The Paris Commune (also contrasting it with the work of Walter Benjamin on the same subject). I then draw out the implications for social and spatial thinking of Badiou's concept of the site (the locus of an Event which is, according to Badiou, the place of the advent of truth).
Requirement for balanced Ca/NFAT signaling in hematopoietic and embryonic development
Authors: Müller Martin R. , Sasaki Yoshiteru , Stevanovic Irena , Lamperti Edward D. , Ghosh Srimoyee , Sharma Sonia , Gelinas Curtis , Rossi Derrick J. , Pipkin Matthew E. , Rajewsky Klaus , Hogan Patrick G. , Rao Anjana
Published: April 2009

NFAT transcription factors are highly phosphorylated proteins residing in the cytoplasm of resting cells. Upon dephosphorylation by the phosphatase calcineurin, NFAT proteins translocate to the nucleus, where they orchestrate developmental and activation programs in diverse cell types. NFAT is rephosphorylated and inactivated through the concerted action of at least 3 different kinases: CK1, GSK-3, and DYRK. The major docking sites for calcineurin and CK1 are strongly conserved throughout vertebrate evolution, and conversion of either the calcineurin docking site to a high-affinity version or the CK1 docking site to a low-affinity version results in generation of hyperactivable NFAT proteins that are still fully responsive to stimulation. In this study, we generated transgenic mice expressing hyperactivable versions of NFAT1 from the ROSA26 locus. We show that hyperactivable NFAT increases the expression of NFAT-dependent cytokines by differentiated T cells as expected, but exerts unexpected signal-dependent effects during T cell differentiation in the thymus, and is progressively deleterious for the development of B cells from hematopoietic stem cells. Moreover, progressively hyperactivable versions of NFAT1 are increasingly deleterious for embryonic development, particularly when normal embryos are also present in utero. Forced expression of hyperactivable NFAT1 in the developing embryo leads to mosaic expression in many tissues, and the hyperactivable proteins are barely tolerated in organs such as brain, and cardiac and skeletal muscle. Our results highlight the need for balanced Ca/NFAT signaling in hematopoietic stem cells and progenitor cells of the developing embryo, and emphasize the evolutionary importance of kinase and phosphatase docking sites in preventing inappropriate activation of NFAT.
“Oh” in Shakespeare
Authors: Person Raymond F.
Published: April 2009

The use of “oh” in conversation has been widely studied. These studies demonstrate various uses of “oh” in different sequences. For example, John Heritage (1984) has identified six different sequences in which “oh” is used as a “change-of-state token”. Ian Hutchby (2001) has demonstrated how “oh” can be used ironically in disputations.

This study compares the observations concerning “oh” in spoken modern English with “oh”/“O” in The First Folio and Early Quartos of William Shakespeare. This comparison demonstrates that all of the identified contemporary uses of “oh” were also used in the Elizabethan English of Shakespeare. Furthermore, the Shakespeare corpus includes some previously unidentified uses of “oh” (for example, “oh” prefacing a refusal to a request) that augment our understanding of “oh”.
Settling the thymus: immigration requirements
Authors: Cyster Jason G.
Published: April 2009

Thymus settling by precursor cells is essential for the production of T cells, yet the immigration requirements are poorly defined. P-selectin and CC chemokine receptor-9 (CCR9) are involved, and settling is favored when existing residents have moved on. A new study strengthens the correlation between niche emptying and the induction of thymic P-selectin and CCR9 ligand, and provides evidence for feedback from the periphery to thymic P-selectin expression via sphingosine-1-phosphate.
The role of acoustics in ecosystem-based fishery management
Authors: Koslow J. Anthony
Published: April 2009

Koslow, J. A. 2009. The role of acoustics in ecosystem-based fishery management. – ICES Journal of Marine Science, 66: 966–973. For more than half a century, acoustics has been a leading tool in fishery stock assessment. Today, the need for ecosystem-based management poses new challenges for fishery scientists: the need to assess the ecological relationships of exploited species with predators and prey and to predict the potential effects of climate variability and climate change on recruitment. No research tool is likely to prove as effective as acoustics in meeting these needs, if it is properly integrated into interdisciplinary research programmes involving ecology and oceanography, as well as fisheries. Integration of data from acoustics and ocean-observation, as well as from satellites and other high-resolution oceanographic mapping tools, is likely to lead to major advances in fishery oceanography. New developments in acoustic technology, such as three-dimensional, multibeam acoustics, and shelf-scale acoustic mapping, may also lead to significant advances. Notwithstanding these developments, critical biases and shortcomings of acoustic methods that were noted 50 years ago remain with us. For example, the identification of insonified biota and single-target discrimination remains relatively primitive. Progress is urgently needed in these basic underpinnings of the acoustic method.
The influence of uncertainty in target strength on abundance indices based on acoustic surveys: examples of the Baltic Sea herring and sprat
Authors: Kasatkina Svetlana M.
Published: April 2009

Kasatkina, S. M. 2009. The influence of uncertainty in target strength on abundance indices based on acoustic surveys: examples of the Baltic Sea herring and sprat. – ICES Journal of Marine Science, 66: 1404–1409. In situ, target-strength (TS) measurements at 38 kHz and an analysis of biometric fish characteristics are presented for the Baltic Sea herring (Clupea harengus membras) and sprat (Sprattus sprattus). It is demonstrated that the application of two TS–length functions for the Baltic Sea clupeids, the first for young herring and sprat and the second for adult herring, is reasonable, and the two functions can therefore replace the well-known equation used since 1983. Parameters of the proposed relationships, accompanied by their statistical characteristics, are included in a model to obtain uncertainty in acoustically derived abundance indices. Major components of survey uncertainty, such as spatial variability, species composition, and size structure, are also included in the simulation. The proposed TS functions should permit estimates of more realistic abundance dynamics of Baltic Sea clupeids, by years and age groups, thereby providing important information for stock assessment models.
Genome sequencing of linezolid-resistant Streptococcus pneumoniae mutants reveals novel mechanisms of resistance
Authors: Feng Jie , Lupien Andréanne , Gingras Hélène , Wasserscheid Jessica , Dewar Ken , Légaré Danielle , Ouellette Marc
Published: April 2009

Linezolid is a member of a novel class of antibiotics, with resistance already being reported. We used whole-genome sequencing on three independent Streptococcus pneumoniae strains made resistant to linezolid in vitro in a step-by-step fashion. Analysis of the genome assemblies revealed mutations in the 23S rRNA gene in all mutants including, notably, G2576T, a previously recognized resistance mutation. Mutations in an additional 31 genes were also found in at least one of the three sequenced genomes. We concentrated on three new mutations that were found in at least two independent mutants. All three mutations were experimentally confirmed to be involved in antibiotic resistance. Mutations upstream of the ABC transporter genes spr1021 and spr1887 were correlated with increased expression of these genes and neighboring genes of the same operon. Gene inactivation supported a role for these ABC transporters in resistance to linezolid and other antibiotics. The hypothetical protein spr0333 contains an RNA methyltransferase domain, and mutations within that domain were found in all S. pneumoniae linezolid-resistant strains. Primer extension experiments indicated that spr0333 methylates G2445 of the 23S rRNA and mutations in spr0333 abolished this methylation. Reintroduction of a nonmutated version of spr0333 in resistant bacteria reestablished G2445 methylation and led to cells being more sensitive to linezolid and other antibiotics. Interestingly, the spr0333 ortholog was also mutated in a linezolid-resistant clinical Staphylococcus aureus isolate. Whole-genome sequencing and comparative analyses of S. pneumoniae resistant isolates was useful for discovering novel resistance mutations.
Apolipoprotein B‐associated cholesterol is a determinant of treatment outcome in patients with chronic hepatitis C virus infection receiving anti‐viral agents interferon‐alpha and ribavirin
Authors: SHERIDAN D. A. , PRICE D. A. , SCHMID M. L. , TOMS G. L. , DONALDSON P. , NEELY D. , BASSENDINE M. F.
Published: April 2009

Background  Hepatitis C virus (HCV) co‐opts very‐low‐density lipoprotein (VLDL) pathways for replication, secretion and entry into hepatocytes and associates with apolipoprotein B (apoB) in plasma. Each VLDL contains apoB‐100 and variable amounts of apolipoproteins E and C, cholesterol and triglycerides.

Aim  To determine whether baseline lipid levels predicted treatment outcome.

Methods  Retrospective analysis was performed of 250 chronic hepatitis C (CHC) patients who had received anti‐viral agents interferon‐alpha and ribavirin; 165 had a sustained virological response (SVR). Pre‐ and post‐treatment nonfasting lipid profiles were measured and non‐high‐density lipoprotein (non‐HDL) cholesterol (i.e. apoB‐associated) was calculated. Binary logistic regression analysis assessed factors independently associated with treatment outcome.

Results  There was an independent association between higher apoB‐associated cholesterol (non‐HDL‐C) and increased odds of SVR (odds ratio 2.09, P = 0.042). In multivariate analysis, non‐HDL‐C was significantly lower in HCV genotype 3 (g3) than genotype 1 (P = 0.007); this was reversible upon eradication of HCVg3 (pre‐treatment non‐HDL‐C = 2.8 mmol/L, SVR = 3.6 mmol/L, P < 0.001).

Conclusions  Higher apoB‐associated cholesterol is positively associated with treatment outcome in CHC patients receiving anti‐viral therapy, possibly due to competition between apoB‐containing lipoproteins and infectious low‐density HCV lipo‐viral particles for hepatocyte entry via shared lipoprotein receptors.
Linkage confirms canine pkd1 orthologue as a candidate for bull terrier polycystic kidney disease
Authors: O’Leary C. A. , Duffy D. , Biros I. , Corley S.
Published: April 2009

Bull terrier polycystic kidney disease (BTPKD) is a Mendelian disorder with many features reminiscent of human autosomal dominant polycystic disease, the latter disease being due to mutations at PKD1 and PKD2 loci. We investigated the role of the canine pkd1 orthologue in BTPKD via linkage analysis of a large kindred in which the disorder is segregating. Twelve microsatellite markers around the canine pkd1 locus (CFA6) were amplified from the genomic DNA of 20 affected and 16 unaffected bull terriers. An additional 28 affected dogs were genotyped at five key microsatellites. A highly significant multi‐point LOD score that peaked over the canine pkd1 locus was observed (LOD = 6.59, best two‐point LOD score LOD = 6.02), implicating this as the BTPKD locus.