bluuebunny/crossref_metadata_2025 huggingface dataset:
Security communities and the habitus of restraint: Germany and the United States on Iraq
Authors: BJOLA CORNELIU , KORNPROBST MARKUS
Published: June 2007

Borrowing from Norbert Elias, we introduce the habitus of restraint to the study of security communities. This habitus constitutes a key dimension of the glue that holds security communities together. The perceived compatibility of practices emanating from the habitus that members hold fosters the collective identity upon which a security community is built. The violation of a member’s habitus by the practices of another member, however, disrupts the reproduction of collective identity and triggers a crisis of the security community. Our analysis of Germany’s reaction to Washington’s case for war against Iraq provides empirical evidence for the salience of the habitus for the internal dynamics of security communities.
Eddy length scales in the North Atlantic Ocean
Authors: Eden Carsten
Published: June 2007

Eddy length scales are calculated from satellite altimeter products and in an eddy‐resolving model of the North Atlantic Ocean. Four different measures for eddy length scales are derived from kinetic energy densities in wave number space and spatial decorrelation scales. Observational estimates and model simulation agree well in all these measures near the surface. As found in previous studies, all length scales are, in general, decreasing with latitude. They are isotropic and proportional to the local first baroclinic Rossby radius (Lr) north of about 30°N, while south of 30°N (or for Lr > 30 km), zonal length scales tend to be larger than meridional ones, and (scalar) length scales show no clear relation to Lr anymore. Instead, they appear to be related to the local Rhines scale. In agreement with a recent theoretical prediction by Theiss [2004], the observed and simulated pattern of eddy length scales appears to be indicative of two different dynamical regimes in the North Atlantic: anisotropic turbulence in the subtropics and isotropic turbulence in the subpolar North Atlantic. Both regions can be roughly characterized by the ration between Lr and the Rhines scales (LR), with LR > Lr in the isotropic region and LR < Lr in the anisotropic region. The critical latitude that separates both regions, i.e., where LR = Lr, is about 30°N.
Dependence of CCN activity of less volatile particles on the amount of coating observed in Tokyo
Authors: Kuwata M. , Kondo Y. , Mochida M. , Takegawa N. , Kawamura K.
Published: June 2007

A novel observation system has been developed to measure cloud condensation nuclei (CCN) activity simultaneously with volatility of aerosol particles at 400°C. CCN/CN ratios were measured using a CCN counter and a condensation particle counter, and volatility was measured with a volatility tandem differential mobility analyzer (VTDMA). This system was connected to a hygroscopicity tandem differential mobility analyzer in tandem to measure these properties of hygroscopicity‐selected particles. These instruments were deployed in Tokyo in November 2004. In Tokyo, the dominant fraction of nonvolatile cores at 400°C has been found to be black carbon (BC). Therefore the number size distribution measured by VTDMA represents the mixing state of black carbon particles. The VTDMA measurement of hygroscopicity‐selected particles revealed that most of the less hygroscopic particles were less volatile, while more hygroscopic particles were more volatile. CCN/CN ratios of less volatile particles [(CCN/CN)LV] are estimated from CCN activity and volatility measurements of less hygroscopic particles. (CCN/CN)LV at SS = 0.5% is correlated with the decrease of peak diameter due to volatilization (Δdm), and (CCN/CN)LV is nearly equal to unity at Δdm = 10 nm. This result suggests that the CCN activity of BC particles significantly depends on the amount of coating.
Atmospheric temperature responses to solar irradiance and geomagnetic activity
Authors: Lu Hua , Jarvis Martin J. , Graf Hans‐F. , Young Peter C. , Horne Richard B.
Published: June 2007

The relative effects of solar irradiance and geomagnetic activity on the atmospheric temperature anomalies (Ta) are examined from the monthly to interdecadal timescales. Geomagnetic Ap (Ap) signals are found primarily in the stratosphere, while the solar F10.7‐cm radio flux (Fs) signals are found in both the stratosphere and troposphere. In the troposphere, 0.1–0.4 K increases in Ta are associated with Fs. Enhanced Fs signals are found when the stratospheric quasi‐biennial oscillation (QBO) is westerly. In the extrapolar region of the stratosphere, 0.1–0.6 and 0.1–0.7 K increases in Ta are associated with solar irradiance and with geomagnetic activity, respectively. In this region, Fs signals are strengthened when either the QBO is easterly, or geomagnetic activity is high, while Ap signals are strengthened when either the QBO is westerly, or solar irradiance is high. High solar irradiance and geomagnetic activity tend to enhance each other's signatures either making the signals stronger and symmetric about the equator or extending the signals to broader areas, or both. Positive Ap signals dominate the middle Arctic stratosphere and are two to five times larger than those of Fs. When solar irradiance is low, the signature of Ap in Ta is asymmetric about the equator, with positive signals in the Arctic stratosphere and negative signals at midlatitudes of the NH stratosphere. Weaker stratospheric QBO signals are associated with high Ap and Fs, suggesting possible disturbances on the QBO. The signals of Ap and Fs are distinct from the positive temperature anomalies resulting from volcanic eruptions.
State and bias estimation for soil moisture profiles by an ensemble Kalman filter: Effect of assimilation depth and frequency
Authors: De Lannoy Gabriëlle J. M. , Houser Paul R. , Pauwels Valentijn R. N. , Verhoest Niko E. C.
Published: June 2007

An ensemble Kalman filter for state estimation and a bias estimation algorithm were applied to estimate individual soil moisture profiles in a small corn field with the CLM2.0 model through the assimilation of measurements from capacitance probes. Both without and with inclusion of bias correction, the effect of the assimilation frequency, the assimilation depth, and the number of observations assimilated per profile were studied. Assimilation of complete profiles had the highest impact on deeper soil layers, and the optimal assimilation frequency was about 1–2 weeks, if bias correction was applied. The optimal assimilation depth depended on the calibration results. Assimilation in the surface layer had typically less impact than assimilation in other layers. Through bias correction the soil moisture estimate greatly improved. In general, the correct propagation of the innovations for both the bias‐blind state and bias filtering from any layer to other layers was insufficient. The approximate estimation of the a priori (bias) error covariance and the choice of a zero‐initialized persistent bias model made it impossible to estimate the bias in layers for which no observations were available.
Ground truth from the Opportunity Rover for Mars thermal inertia data
Authors: Hynek Brian M. , Singer Kelsi
Published: June 2007

The temperature of the Martian surface has been measured by a number of spacecraft and numerical models of the surface thermal response constrain the near‐surface physical properties. The results allow inferences regarding the surface layer and help determine potential hazards for landed spacecraft. However, thermal models generally do not incorporate the degree of surface complexity that is seen from landers. Here we examine potential contributions to the thermal response along the Opportunity Rover's traverse by using ground truth in conjunction with orbiter data from the THEMIS instrument on Mars Odyssey. We show that the size distribution of the ubiquitous hematite spherules varies in a way that is consistent with expectations from orbiter data. Secondly, exposures of bedrock along Opportunity's traverse have no observable effect on the bulk thermal response seen from orbit. These field observations are an important step toward improving understanding of the physical composition of the Martian surface.
Studies of the defect structures and g factors for two trigonal Ti3+ centers in LaMgAl11O19:Ti3+ crystal
Authors: Wen-Chen Zheng , Wang Fang
Published: June 2007

The defect models of two trigonal Ti3+ centers in the LaMgAl11O19:Ti3+ (LMA:Ti3+) crystal are resuggested as center 1 at the 2a site and center 3 at the 4f site. By using the crystal field parameters Dq based on the suggestion, the g factors g∥ and g⊥ for both Ti3+ centers are calculated from two microscopic spin-Hamiltonian theory methods, the complete diagonalization (of the energy matrix) method (CDM) and the perturbation theory method (PTM), based on the two spin-orbit (SO) parameter model (where both the contribution to spin-Hamiltonian parameters from the SO coupling parameter of the central 3dn ion and that of ligand ions are included). The calculated results from CMD and PTM are not only close to each other, but are also in agreement with the observed values. This suggests that (i) the present defect models of the two Ti3+ centers in the LMA:Ti3+ crystal are suitable and (ii) both CDM and PTM methods are effective to the explanations of spin-Hamiltonian parameters of 3d1 ions in crystals. The defect structures of both Ti3+ centers (which are quite different from the corresponding structures in the host LMA crystal, in particular, for center 1, the oxygen octahedron changes from the trigonal elongation in the host LMA crystal to the trigonal compression in the Ti3+ center) are also estimated from the calculations. The results are discussed.
Investigation of intrinsic gettering for germanium doped Czochralski silicon wafer
Authors: Chen Jiahe , Yang Deren , Ma Xiangyang , Wang Weiyan , Zeng Yuheng , Que Duanlin
Published: June 2007

The intrinsic gettering (IG) effects in a germanium-doped Czochralski (GCz) silicon wafer have been investigated through a processing simulation of dynamic random access memory making and an evaluation on IG capability for copper contamination. It has been suggested that both the good quality defect-free denuded zones (DZs) and the high-density bulk microdefect (BMD) regions could be generated in GCz silicon wafer during device fabrication. Meanwhile, it was also indicated that the tiny oxygen precipitates were hardly presented in DZs of silicon wafer with the germanium doping. Furthermore, it was found in GCz silicon wafer that the BMDs were higher in density but smaller in size in contrast to that in conventional Cz silicon wafer. Promoted IG capability for metallic contamination was therefore induced in the germanium-doped Cz silicon wafer. A mechanism of the germanium doping on oxygen precipitation in Cz silicon was discussed, which was based on the hypothesis of germanium-related complexes.
Near infrared long lasting emission of Yb3+ and its influence on the optical storage ability of Mn2+-activated zinc borosilicate glasses
Authors: Li Chengyu , Wang Jing , Liang Hongbin , Su Qiang
Published: June 2007

The near infrared long lasting phosphorescence of Yb3+ is observed in Yb3+ and Mn2+ codoped zinc borosilicate glasses. Compared with the glasses solely activated by Mn2+, when the Yb3+ ion is codoped, the red long lasting phosphorescence of the samples is largely improved in both brightness and persistent time but the photostimulated long lasting phosphorescence is greatly depressed. It is considered that the appearance of the phosphorescence of Yb3+ is due to the alteration of the energy transfer channel; additionally, Yb3+ also changes the trap depth of the glasses with the shallower trap predominating therefrom the red long lasting phosphorescence is improved and the photostimulated long lasting phosphorescence is degraded.
Characterization of superparamagnetic nanoparticles by analyzing the magnetization and relaxation dynamics using fluxgate magnetometers
Authors: Ludwig F. , Heim E. , Schilling M.
Published: June 2007

We have investigated the magnetization and relaxation dynamics of diluted, freeze-dried superparamagnetic magnetite (Fe3O4) nanoparticle samples with organic shells using a differential fluxgate magnetorelaxometry system. The experimental data were analyzed within the framework of the moment superposition model (MSM), providing information on size and size distribution of particle cores as well as on magnetic properties such as saturation magnetization and anisotropy constant. The MSM was refined by introducing an expression for the Néel time constant depending on magnetic field, anisotropy energy, saturation magnetization, and orientation of the magnetic moment of an individual magnetic nanoparticle (MNP) with respect to the external magnetic field. It is shown that especially the dependence of the magnetization and relaxation curves on magnetizing field and magnetization time provides valuable information for an unambiguous and comprehensive determination of MNP core parameters. All experimental findings could be explained with the refined MSM; however, so far, no self-consistent parameter set was obtained quantitatively explaining all measured data. Deviations from the assumed lognormal distribution of core sizes and yet too simplified expressions for the Néel time constant are discussed as potential reasons for the observed discrepancies.
Localized laser trimming of critical current in niobium based Josephson devices
Authors: Granata C. , Vettoliere A. , Petti L. , Rippa M. , Ruggiero B. , Mormile P. , Russo M.
Published: June 2007

A thermal annealing technique for Nb∕Al–AlOx∕Nb Josephson devices based on laser heating is presented. This technique allows “locally” modifying the Josephson critical current density, which is not possible using standard procedures based on oven or hot plate heating. In fact, the heating of a single circuit element with a good spatial resolution is possible. At room temperature, the selected junction is exposed to a focused Ar+ laser beam aligned by an optical system. A thermographic imaging allows controlling the temperature distribution on the whole chip. Experimental results on high quality Josephson junction measured in liquid helium have shown a continuous reduction of the critical current density up to about 40%. Neighboring junctions have not exhibited any measurable change ensuring the capability to locally modify the Josephson critical current density. As first application, the present technique has been employed to recover noisy dc superconducting quantum interference device magnetometers with nonoptimal critical current values obtaining a reduction of the spectrum density of magnetic field noise from about 30to2.5fT∕Hz1∕2.
Effects of microwave irradiation on the dehydriding reaction of the composites of lithium borohydride and microwave absorber
Authors: Matsuo Motoaki , Nakamori Yuko , Yamada Keitaro , Orimo Shin-ichi
Published: June 2007

Effects of microwave irradiation on the dehydriding reaction of the composites of LiBH4 and a microwave absorber such as TiH2, B, or C were experimentally investigated. The composites with TiH2 exhibited faster temperature increases than pure LiBH4; however, they took more than 30min to release hydrogen. In contrast, the composites with B or C as efficient microwave absorbers were heated much more rapidly to release 6 mass % hydrogen within 5min. The composites with C were superior to those with B, probably due to the higher thermal conductivity of C.
Adaptive bonding technique for precise assembly of three-dimensional microstructures
Authors: Park Sang-Hu , Jeong Jun-Ho , Choi Dae-Geun , Kim Ki-Don , Altun Ali Ozhan , Lee Eung-Sug , Yang Dong-Yol , Lee Kwang-Sup
Published: June 2007

Precise fabrication of three-dimensional (3D) self-standing microstructures on thin glass plates via two-photon induced polymerization (TPP) has been an important issue for innovative 3D nanodevices and microdevices. However, there are still issues remaining to be solved, such as building 3D microstructures on opaque materials via TPP and being able to implant them as functional parts onto practical systems. To settle these issues simply and effectively, the authors propose a contact print lithography (CPL) method using an ultraviolet-curable polymer layer. They report some of the possibilities and potential of CPL by presenting their results for transplanting 3D microstructures onto large-area substrates and also their examination of some of the effects of the process parameters on CPL.
Reversible and irreversible current induced domain wall motion in CoFeB based spin valves stripes
Authors: Laribi S. , Cros V. , Muñoz M. , Grollier J. , Hamzić A. , Deranlot C. , Fert A. , Martínez E. , López-Díaz L. , Vila L. , Faini G. , Zoll S. , Fournel R.
Published: June 2007

The authors present results on current induced domain wall motion in Co∕Cu∕CoFeB trilayered stripes. The threshold current densities are around 106A∕cm2 at zero field, i.e., about two orders of magnitude smaller than in single NiFe stripes. The domain wall motion is assisted when the field torque acts in the same direction as the spin torque. When the field torque is opposed to the spin transfer one and above a threshold field, the authors observe a reversible displacement of the domain wall (peak in the dV∕dI measurements). This can be ascribed to the onset of domain wall fluctuations, which is confirmed by micromagnetic simulations.
Femtosecond nonlinear optical properties of lead-germanium oxide amorphous films
Authors: Rativa Diego , de Araujo Renato E. , de Araújo Cid B. , Gomes Anderson S. L. , Kassab Luciana R. P.
Published: June 2007

The nonlinear (NL) response of lead-germanium oxide amorphous films was investigated using a Ti:saphire laser delivering pulses of ≈150fs at 800nm. The Kerr shutter technique was employed to reveal the time response of the nonlinearity that is smaller than 150fs. The sign and magnitude of the nonlinearity were obtained using a novel technique called thermally managed eclipse Z scan which allows the simultaneous characterization of cumulative and noncumulative NL effects. The NL refractive index of electronic origin, n2≈2×10−17m2∕W, and the NL absorption coefficient, α2≈3×103cm∕GW, were determined.
Self-annihilation of electron-irradiation-induced defects in InAsxP1−x∕InP multiquantum well solar cells
Authors: Khan Aurangzeb , Freundlich A. , Gou Jihua , Gapud A. , Imazumi M. , Yamaguchi M.
Published: June 2007

Irradiation by 1MeV electron of InAsxP1−x∕InP multiquantum well (MQW) solar cells results in the appearance of a dominant electron-emitting level E1, in the upper half of the band gap. The level E1, however, exhibits an interesting behavior as it was found to completely anneal out with storage at room temperature with no change in other majority carrier levels. No any other defect has been observed in electron-irradiated n-type InAsxP1−x∕InP MQW solar cell structures, which contrasts to conventional n-InP solar cell counterparts (structures without QWs). The study reveals that introduction of QWs in the intrinsic region of p-i-n structures enhances significantly the device radiation tolerance well beyond what has been thus far reported for conventional Si or III-V semiconductor-based solar cells.
On the connection between Gaussian statistics and excited-state linear response for time-dependent fluorescence
Authors: Laird Brian B. , Thompson Ward H.
Published: June 2007

Time-dependent fluorescence (TDF) of a chromophore in a polar or nonpolar solvent is frequently simulated using linear-response approximations. It is shown that one such linear-response-type approximation for the TDF Stokes shift derived by Carter and Hynes [J. Chem. Phys. 94, 5961 (1991)] that is based on excited-state dynamics gives the same result as that obtained by assuming Gaussian statistics for the energy gap. The derivation provides insight into the much discussed relationship between linear response and Gaussian statistics. In particular, subtle but important differences between the two approximations are illuminated that suggest that the result is likely more generally applicable than suggested by the usual linearization procedure. In addition, the assumption of Gaussian statistics directly points to straightforward checks of the validity of the approximation with essentially no additional computational effort.
Imaging protein interactions with bioluminescence resonance energy transfer (BRET) in plant and mammalian cells and tissues
Authors: Xu Xiaodong , Soutto Mohammed , Xie Qiguang , Servick Stein , Subramanian Chitra , von Arnim Albrecht G. , Johnson Carl Hirschie
Published: June 2007

FRET is a well established method for cellular and subcellular imaging of protein interactions. However, FRET obligatorily necessitates fluorescence excitation with its concomitant problems of photobleaching, autofluorescence, phototoxicity, and undesirable stimulation of photobiological processes. A sister technique, bioluminescence resonance energy transfer (BRET), avoids these problems because it uses enzyme-catalyzed luminescence; however, BRET signals usually have been too dim to image effectively in the past. Using a new generation electron bombardment-charge-coupled device camera coupled to an image splitter, we demonstrate that BRET can be used to image protein interactions in plant and animal cells and in tissues; even subcellular imaging is possible. We have applied this technology to image two different protein interactions: (
i
) dimerization of the developmental regulator, COP1, in plant seedlings; and (
ii
) CCAAT/enhancer binding protein α (C/EBPα) in the mammalian nucleus. This advance heralds a host of applications for imaging without fluorescent excitation and its consequent limitations.
Three-dimensional structure of a human connexin26 gap junction channel reveals a plug in the vestibule
Authors: Oshima Atsunori , Tani Kazutoshi , Hiroaki Yoko , Fujiyoshi Yoshinori , Sosinsky Gina E.
Published: June 2007

Connexin molecules form intercellular membrane channels facilitating electronic coupling and the passage of small molecules between adjoining cells. Connexin26 (Cx26) is the second smallest member of the gap junction protein family, and mutations in Cx26 cause certain hereditary human diseases such as skin disorders and hearing loss. Here, we report the electron crystallographic structure of a human Cx26 mutant (M34A). Although crystallization trials used hemichannel preparations, the density map revealed that two hemichannels redocked at their extracellular surfaces into full intercellular channels. These orthorhombic crystals contained two sets of symmetry-related intercellular channels within three lipid bilayers. The 3D map shows a prominent density in the pore of each hemichannel. This density contacts the innermost helices of the surrounding connexin subunits at the bottom of the vestibule. The density map suggests that physical blocking may play an important role that underlies gap junction channel regulation. Our structure allows us to suggest that the two docked hemichannels can be independent and may regulate their activity autonomously with a plug in the vestibule.
Pinching holomorphic correspondences
Authors: Bullett Shaun , Haïssinsky Peter
Published: June 2007

For certain classes of holomorphic correspondences which are matings between Kleinian groups and polynomials, we prove the existence of pinching deformations, analogous to Maskit’s deformations of Kleinian groups which pinch loxodromic elements to parabolic elements. We apply our results to establish the existence of matings between quadratic maps and the modular group, for a large class of quadratic maps, and of matings between the quadratic mapz→z2z\to z^2and circle-packing representations of the free productC2∗C3C_2*C_3of cyclic groups of order22and33.
Finding cis-regulatory modules in Drosophila using phylogenetic hidden Markov models
Authors: Wong Wendy S.W. , Nielsen Rasmus
Published: June 2007

Motivation: Finding the regulatory modules for transcription factors binding is an important step in elucidating the complex molecular mechanisms underlying regulation of gene expression. There are numerous methods available for solving this problem, however, very few of them take advantage of the increasing availability of comparative genomic data.

Results: We develop a method for finding regulatory modules in Eukaryotic species using phylogenetic data. Using computer simulations and analysis of real data, we show that the use of phylogenetic hidden Markov model can lead to an increase in accuracy of prediction over methods that do not take advantage of the data from multiple species.

Availability: The new method is made accessible under GPL in a new publicly available JAVA program: EvoPromoter. It can be downloaded at http://sourceforge.net/projects/evopromoter/

Contact:  sww8@cornell.edu
Virulence of a mouse-adapted Semliki Forest virus strain is associated with reduced susceptibility to interferon
Authors: Deuber Stefan A. , Pavlovic Jovan
Published: June 2007

Type I interferons (IFNs) are essential components of the innate immune system. This study characterized the distinct IFN sensitivities of two closely related Semliki Forest virus (SFV) strains in cell culture. The virulent L10 strain was derived from the original virus isolate by propagation in mice. In contrast, the avirulent SFV strain, designated V42, was derived from an earlier passage of the original virus isolated from mosquitoes. The virulent L10 strain produced a cytopathic effect (CPE) in IFN-treated cells and the production of infectious virus was only two orders of magnitude lower compared with untreated cells. In contrast, the avirulent V42 exerted no CPE in IFN-treated cells and production of infectious virus was four orders of magnitude lower compared with untreated cells. The reduced CPE in IFN-treated cells infected with the avirulent V42 strain was due to inhibition of productive infection and not to reduced cell death. The virulent L10 strain synthesized less genomic RNA but more non-structural proteins than the avirulent V42 strain, suggesting more efficient translation of the L10 genomic RNA. Using a cell line unable to produce IFN, it was shown that the reduced susceptibility of the L10 strain to the action of IFN was not due to reduced IFN induction. Hence, the reduced susceptibility of the virulent L10 strain to the action of IFN allows it to overcome the established IFN-induced antiviral state of the cell, thereby increasing its virulence.
Differential cleavage of the norovirus polyprotein precursor by two active forms of the viral protease
Authors: Scheffler Ulrike , Rudolph Wolfram , Gebhardt Julia , Rohayem Jacques
Published: June 2007

Protein translation in noroviruses requires translational processing of a polyprotein precursor by the viral protease. So far, the molecular mechanisms of catalytic cleavage by the viral protease are poorly understood. In this study, the catalytic activities and substrate specificities of the viral protease were examinedin vitroby using synthetic peptides (11–15 residues) corresponding to the cleavage sites of the norovirus polyprotein. Both predicted forms of the viral protease, the 3C-like protease (3Cpro) and the 3CD-like protease polymerase protein (3CDpropol), displayed a specifictranscleavage activity of peptides bearing Gln–Gly at the scissile bond. In contrast, peptides bearing Glu–Gly at the scissile bond (p20/VPg and 3Cpro/3Dpoljunctions) were resistant totrans-cleavage by 3Cproand 3CDpropol. Interestingly, the VPg/3Cproscissile bond (Glu–Ala) was cleaved only by 3CDpropol, and examination of relative cleavage efficiencies revealed significant differences in processing of peptides, indicating differential cleavage patterns for 3Cproand 3CDpropol.
Infection of cynomolgus macaques (Macaca fascicularis) and rhesus macaques (Macaca mulatta) with different wild-type measles viruses
Authors: El Mubarak H. Sittana , Yüksel Selma , van Amerongen Geert , Mulder Paul G. H. , Mukhtar Maowia M. , Osterhaus Albert D. M. E. , de Swart Rik L.
Published: June 2007

Both rhesus and cynomolgus macaques have been used as animal models for measles vaccination and immunopathogenesis studies. A number of studies have suggested that experimental measles virus (MV) infection induces more-characteristic clinical features in rhesus than in cynomolgus monkeys. In the present study, both macaque species were infected with two different wild-type MV strains and clinical, virological and immunological parameters were compared. The viruses used were a genotype C2 virus isolated in The Netherlands in 1991 (MV-Bil) and a genotype B3 virus isolated from a severe measles case in Sudan in 1997 (MV-Sudan). Following infection, all rhesus monkeys developed a skin rash and conjunctivitis, which were less obvious in cynomolgus monkeys. Fever was either mild or absent in both species. Virus reisolation profiles from peripheral blood mononuclear cells and broncho-alveolar lavage cells and the kinetics of MV-specific IgM and IgG responses were largely identical in the two animal species. However, in animals infected with MV-Sudan, viraemia appeared earlier and lasted longer than in animals infected with MV-Bil. This was also reflected by the earlier appearance of MV-specific serum IgM antibodies after infection with MV-Sudan. Collectively, these data show that cynomolgus and rhesus macaques are equally susceptible to wild-type MV infection, although infection in the skin seems to follow a different course in rhesus macaques. MV-Sudan proved more pathogenic for non-human primates than MV-Bil, which may render it more suitable for use in future pathogenesis studies.
Absence of viral escape within a frequently recognized HLA-A26-restricted CD8+ T-cell epitope targeting the functionally constrained hepatitis C virus NS5A/5B cleavage site
Authors: Neumann-Haefelin Christoph , Killinger Thomas , Timm Jörg , Southwood Scott , McKinney Denise , Blum Hubert E. , Thimme Robert
Published: June 2007

CD8+ T-cell responses are central for the resolution of hepatitis C virus (HCV) infection, and viral escape from these CD8+ T-cell responses has been suggested to play a major role in HCV persistence. However, the factors determining the emergence of CD8 escape mutations are not well understood. Here, the first identification of four HLA-A26-restricted CD8+ T-cell epitopes is reported. Of note, two of these four epitopes are located in the NS3/4A and NS5A/5B cleavage sites. The latter epitope is targeted in all (three of three) patients with acute, resolving HCV infection and in a relatively high proportion (four of 14) of patients with chronic HCV infection. Importantly, the epitope corresponding to the NS5A/5B cleavage site is characterized by the complete absence of sequence variations, despite the presence of functional virus-specific CD8+ T cells in our cohort. These results support previous findings that showed defined functional constraints within this region. They also suggest that the absence of viral escape may be determined by viral fitness cost and highlight an attractive target for immunotherapies.
Infection with recombinant orf viruses demonstrates that the viral interleukin-10 is a virulence factor
Authors: Fleming Stephen B. , Anderson Ian E. , Thomson Jackie , Deane David L. , McInnes Colin J. , McCaughan Catherine A. , Mercer Andrew A. , Haig David M.
Published: June 2007

Orf virus is the prototype parapoxvirus that causes the contagious skin disease orf. It encodes an orthologue of the cytokine interleukin (IL)-10. Recombinant orf viruses were constructed in which the viral interleukin-10 (vorfIL-10) was disabled (vorfIL-10ko) and reinserted (vorfrevIL-10) at the same locus and compared to wild-type virus for their ability to induce skin lesions in sheep. After either primary infection or reinfection, smaller less severe lesions were recorded in the vorfIL-10ko-infected animals compared with either of the vorfIL-10-intact virus-infected animals. Thus, the vorfIL-10ko virus was attenuated compared with the vorfIL-10 intact viruses, demonstrating that orf virus IL-10 is a virulence factor. The virus IL-10 is one of several virulence or immuno-modulatory factors expressed by orf virus. Removal of any one of these genes would be expected to have only a partial effect on virulence, which is what was observed in this study with vorfIL-10.
Mutations at the palmitoylation site of non-structural protein nsP1 of Semliki Forest virus attenuate virus replication and cause accumulation of compensatory mutations
Authors: Žusinaite Eva , Tints Kairit , Kiiver Kaja , Spuul Pirjo , Karo-Astover Liis , Merits Andres , Sarand Inga
Published: June 2007

The replicase of Semliki Forest virus (SFV) consists of four non-structural proteins, designated nsP1–4, and is bound to cellular membranes via an amphipathic peptide and palmitoylated cysteine residues of nsP1. It was found that mutations preventing nsP1 palmitoylation also attenuated virus replication. The replacement of these cysteines by alanines, or their deletion, abolished virus viability, possibly due to disruption of interactions between nsP1 and nsP4, which is the catalytic subunit of the replicase. However, during a single infection cycle, the ability of the virus to replicate was restored due to accumulation of second-site mutations in nsP1. These mutations led to the restoration of nsP1–nsP4 interaction, but did not restore the palmitoylation of nsP1. The proteins with palmitoylation-site mutations, as well as those harbouring compensatory mutations in addition to palmitoylation-site mutations, were enzymically active and localized, at least in part, on the plasma membrane of transfected cells. Interestingly, deletion of 7 aa including the palmitoylation site of nsP1 had a relatively mild effect on virus viability and no significant impact on nsP1–nsP4 interaction. Similarly, the change of cysteine to alanine at the palmitoylation site of nsP1 of Sindbis virus had only a mild effect on virus replication. Taken together, these findings indicate that nsP1 palmitoylation as such is not the factor determining the ability to bind to cellular membranes and form a functional replicase complex. Instead, these abilities may be linked to the three-dimensional structure of nsP1 and the capability of nsP1 to interact with other components of the viral replicase complex.
Murine gammaherpesvirus-68 productively infects immature dendritic cells and blocks maturation
Authors: Hochreiter Romana , Ptaschinski Catherine , Kunkel Steven L. , Rochford Rosemary
Published: June 2007

Many viruses have evolved mechanisms to evade host immunity by subverting the function of dendritic cells (DCs). This study determined whether murine gammaherpesvirus-68 (γHV-68) could infect immature or mature bone-marrow-derived DCs and what effect infection had on DC maturation. It was found thatγHV-68 productively infected immature DCs, as evidenced by increased viral titres over time. If DCs were induced to mature by exposure to LPS and then infected withγHV-68, only a small percentage of cells was productively infected. However, limiting-dilution assays to measure viral reactivation demonstrated that the mature DCs were latently infected withγHV-68. Electron microscopy revealed the presence of capsids in the nucleus of immature DCs but not in mature DCs. Interestingly, infection of immature DCs byγHV-68 did not result in upregulation of the co-stimulatory molecules CD80 and CD86 or MHC class I and II, or induce cell migration, suggesting that the virus infection did not induce DC maturation. Furthermore,γHV-68 infection of immature DCs did not result in elevated interleukin-12, an important cytokine in the induction of T-cell responses. Finally, lipopolysaccharide and poly(I : C) stimulation ofγHV-68-infected immature DCs did not induce increases in the expression of co-stimulatory molecules and MHC class I or II compared with mock-treated cells, suggesting thatγHV-68 infection blocked maturation. Taken together, these data demonstrate thatγHV-68 infection of DCs differs depending on the maturation state of the DC. Moreover, the block in DC maturation suggests a possible immunoevasion strategy byγHV-68.
Eye-blink conditioning is associated with changes in synaptic ultrastructure in the rabbit interpositus nuclei
Authors: Weeks Andrew C.W. , Connor Steve , Hinchcliff Richard , LeBoutillier Janelle C. , Thompson Richard F. , Petit Ted L.
Published: June 2007

Eye-blink conditioning involves the pairing of a conditioned stimulus (usually a tone) to an unconditioned stimulus (air puff), and it is well established that an intact cerebellum and interpositus nucleus, in particular, are required for this form of classical conditioning. Changes in synaptic number or structure have long been proposed as a mechanism that may underlie learning and memory, but localizing these changes has been difficult. Thus, the current experiment took advantage of the large amount of research conducted on the neural circuitry that supports eye-blink conditioning by examining synaptic changes in the rabbit interpositus nucleus. Synaptic quantifications included total number of synapses per neuron, numbers of excitatory versus inhibitory synapses, synaptic curvature, synaptic perforations, and the maximum length of the synapses. No overall changes in synaptic number, shape, or perforations were observed. There was, however, a significant increase in the length of excitatory synapses in the conditioned animals. This increase in synaptic length was particularly evident in the concave-shaped synapses. These results, together with previous findings, begin to describe a sequence of synaptic change in the interpositus nuclei following eye-blink conditioning that would appear to begin with structural change and end with an increase in synaptic number.
Pathophysiology of Hypertension in the Elderly
Authors: VanAuker Michael D. , Storm Joel A.
Published: June 2007

The onset and progression of hypertension is associated with alterations in structure, function, and hemodynamics of the heart, vascular system, and other major organs. An understanding of the structural and functional changes in the cardiovascular system associated with this process would allow for early detection and the development of treatment strategies. In this paper, we focus on the anatomic alterations that accompany vascular aging and the resulting cardiovascular dynamics. Techniques to measure changes in cardiovascular dynamics and left ventricular performance are reviewed. The impact of therapeutic strategies on cardiovascular dynamics and left ventricular function are also discussed.
Treatment of Hypertension in the Institutionalized Elderly
Authors: Aronow Wilbert S.
Published: June 2007

The goal of antihypertensive therapy in elderly institutionalized persons is to reduce the blood pressure to <140/90 mm Hg if possible. Elderly persons with diastolic hypertension should have their diastolic blood pressure lowered to 80–85 mm Hg. Elderly persons with stage 2 or 3 hypertension, stage 1 hypertension and target organ damage, evidence of clinical cardiovascular disease, or diabetes mellitus should be treated with antihypertensive drug therapy immediately in addition to lifestyle modification. The initial antihypertensive drug in elderly persons without associated medical conditions should be a diuretic or β‐blocker because these drugs have been shown to decrease cardiovascular morbidity and mortality in controlled clinical trials. The initial antihypertensive drug in elderly persons should depend on the associated medical condition. If a second antihypertensive drug is indicated, a drug from another class should be administered. If a diuretic is not the initial drug, it is usually indicated as the second drug. If the antihypertensive response is inadequate after reaching the full dose of two classes of drugs, a third drug from another class should be added. Causes of secondary hypertension should be identified and treated.
An Elderly Man With Progressive Dyspnea on Exertion and Atrial Fibrillation as Manifestations of Senile Cardiac Amyloidosis
Authors: Yunis Nidal A. , Petrasko Marion S. , Cannistra Lauralyn B.
Published: June 2007

Senile cardiac amyloidosis is a form of amyloidosis seen more commonly in the elderly population. It was previously believed to have no functional significance, but more recent studies suggest that it is an important cause for cardiovascular morbidity and mortality in the elderly. The diagnosis may be challenging and it is important to have a high suspicion for this disease in the proper clinical setting. A patient with cardiac amyloidosis is presented in this paper to illustrate the clinical context in which one should consider this diagnosis. Information regarding diagnostic evaluation and a brief review of senile cardiac amyloidosis is presented.
Rotational Atherectomy in Octogenarians: Results and Follow Up
Authors: Cohen Barry M. , Blum Mark A. , Weber Vance J. , Kammona Hussein , Phillips Ann , Daniels Sharon , Mirabella Diane , Santiago Derek , Banas John S.
Published: June 2007

We examined our first 390 rotational atherectomy procedures to determine success and complications rates of patients aged ≥80 (Group I, N=35) as compared to those younger (Group II, N=355). Procedural success was achieved in 32/35 (91%) of Group I and 42/355 (96%) of Group II patients (p=NS). Coronary artery bypass graft surgery was required in 2/35 (5.7%) of Group I and 7/355 (2%) of Group II patients. No deaths, Q wave infarctions, or perforations occurred in the elderly patients and only one of each was observed in the younger group. During clinical follow up (26 months, 3–50), 4/25 patients (16%) in the octogenarian group died. Two of the deaths were cardiac (including the only crossover to surgery). One patient who sustained a late non Q myocardial infarction was asymptomatic. Of the remaining 20 patients the anginal class was 0–II in 19 and III in one. Rotational atherectomy can achieve excellent short and long term outcomes in selected octogenarians.
Transesophageal Echocardiographic Assessment of Proximal Coronary Artery Stenosis in Elderly Patients With Ischemic Stroke
Authors: Voros Szilard , Nanda Navin C.
Published: June 2007

Coronary artery disease is common in elderly patients with ischemic stroke. Most patients with ischemic stroke undergo transesophageal echocardiography to rule out cardiac sources of cerebral embolism. Transesophageal echocardiography has been shown to be very accurate in diagnosing significant proximal coronary artery stenosis, and may be used to evaluate the coronary arteries for the presence of stenosis in elderly patients with ischemic stroke. Transesophageal echocardiographic detection of these lesions might lead to subsequent coronary angiography and revascularization, dramatically changing the management and outcome of these patients.
Quality of Life and Self Efficacy in Cardiac Rehabilitation Patients Over 70 Years of Age Following Acute Myocardial Infarction and Bypass Revascularization Surgery
Authors: McConnell Timothy R. , Laubach Charles A. , Memon Mumtaz , Gardner Jacqueline K. , Klinger Troy A. , Palm Rebecca J.
Published: June 2007

Does 12 weeks of cardiac rehabilitation improve quality of life and self efficacy in patients >70 years of age following an acute myocardial infraction or bypass surgery? Three hundred forty four patients were divided into an Older group (70–89 years of age; n=122) and a younger group (50–69 years of age; n=222). Two hundred fifteen had bypass surgery (Surgical group) and 129 had a myocardial infarction (MI group). Quality of life emotions domain was greater for the Older group at week 12 (p=0.066). The Surgical group had greater increases in overall quality of life and quality of life limitations domain (p=0.012; p<0.001). Self efficacy scores were greater for the Younger group. MI group had greater self efficacy at week 1, while the Surgical group was greater at week 12 (p<0.001). These results suggest age and diagnosis related differences in quality of life and self efficacy.
Ethical Issues in the Management of Geriatric Cardiac Patients
Authors: Crowell Pamela C. , Basta Lofty L.
Published: June 2007

Ethical Issue: A terminally ill patient changes his mind and opts for futile intervention after discovering that his insurance will pay for it.
Apoptosis in Cardiovascular Aging Research: Future Directions
Authors: Duque Gustavo
Published: June 2007

Apoptosis is the process by which cells are induced to activate their own suicide. Programmed cell death occurs in a wide variety of cell types, including cardiovascular tissues. There is increasing evidence of a relationship between apoptosis and cardiovascular disease, particularly ischemic heart disease and congestive heart failure, the most frequent heart diseases in the older population. Research directed to the treatment and possible prevention of apoptosis may provide a means of decreasing the incidence of cardiac failure and increasing the survival of endothelial and smooth muscle cells in the elderly.
Elderly Patients with Acute Coronary Syndromes: Higher Risk and Greater Benefit from Antithrombotic and Interventional Therapies
Authors: Cannon Christopher P.
Published: June 2007

In elderly patients with acute coronary syndromes, outcomes are poorer than in younger patients and, disappointingly, some therapies—including thrombolysis for ST elevation myocardial infarction—confer less benefit than in younger patients. In contrast, in unstable angina and non‐ST elevation myocardial infarction, the elderly appear to derive greater relative and absolute benefit from the newer, more potent antithrombotic therapies. In both the Efficacy and Safety of Subcutaneous Enoxaparin in Non‐Q‐Wave Coronary Events and Thrombolysis in Myocardial Infarction 11B trials, the low molecular weight heparin enoxaparin, compared with unfractionated heparin, appeared to have greater relative and absolute benefit in patients aged 65 years and older, as compared with younger patients. For the glycoprotein IIb/IIIa inhibitors, an equivalent relative benefit has been observed, which translated into a greater absolute benefit in older vs. younger patients. Similarly, in the FRagmin and Fast Revascularisation during InStability in Coronary Artery Disease II trial, patients 65 years and older derived significantly greater benefit from an invasive than from a conservative strategy, whereas there was no difference in outcome by strategy in younger patients. A similar trend was observed in the Thrombolysis in Myocardial Infarction IIIB trial. Thus, in unstable angina and non‐ST elevation myocardial infarction, elderly patients are at higher risk and appear to derive particular benefit from the more aggressive antithrombotic and interventional therapies.
Ischemic Heart Disease in the Elderly: A Need to Understand the Causes of High Mortality After Acute Myocardial Infarction
Authors: Bueno Héctor
Published: June 2007

The short‐ and long‐term mortality of patients >75 years of age with acute myocardial infarction is still very high. These patients have been excluded from most randomized controlled trials designed to test interventions directed to improve the outcome of acute myocardial infarction. Contrary to young‐old patients (65–74 years) in whom the benefit obtained with these interventions is even greater than that observed in younger patients, there is a lack of information concerning the optimal treatment of acute myocardial infarction in the oldest patients. Research specifically directed to assess the optimal reperfusion strategy and coadjuvant therapies in patients >75 years old is critically important. The causes for such high mortality are still poorly understood. Several clinical observations suggest that old patients with acute myocardial infarction have specific pathophysiologic behaviors. As the knowledge of the mechanisms of disease is, in clinical practice, the basis of therapy development, clinical and basic research designed to elucidate the specific pathophysiological mechanisms and causes of the high mortality in the oldest patients with acute myocardial infarction should be regarded as a priority in geriatric cardiovascular research.