bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactive‐Injecting Follow‐Through Shaped Charges from Sequent‐Material Conical Liners
Authors: Schilling Thomas J.
Published: August 2007

Shaped charges using reactive‐metal liners have the potential for beyond‐penetration effects, e.g. thermodynamic events that increase pressure in a volume adjacent to the penetration. Shaped charge liners made from a copper penetrating‐ and an aluminum reactive‐component in a sequent‐material configuration were compared in tests to baseline homogeneous copper liners. Copper lined shaped charges had greater mild steel penetration performance, but lacked beyond‐penetration pressurization effects exhibited by the sequent‐material lined units. Jet capture experiments, beyond‐penetration constant‐volume tests, and thermochemical equilibrium calculations provide evidence supporting the aluminum slug comminution into unoxidized reactive fuel, augmenting beyond‐penetration effects.
Theoretical Prediction of Heats of Sublimation of Energetic Materials Using Pseudo‐Atomic Orbital Density Functional Theory Calculations
Authors: Hu Anguang , Larade Brian , Dudiy Sergey , Abou‐Rachid Hakima , Lussier Louis‐Simon , Guo Hong
Published: August 2007

We present a predictive model for the heats of sublimation of the condensed phases of energetic materials that combine the empirical relations of Politzer with first‐principles density‐functional calculations of the electronic properties of the molecular surfaces. The distinct features of our methodology are the use of numerical pseudo‐atomic orbitals for the quantum mechanical calculation of the electronic charge density, as well as an improved technique for the molecular surface area determination. As applications, we used our model to predict heats of sublimation of energetic molecules CL‐20, HMX, RDX, TNT, FOX‐7, TATB, and LLM‐105, with the Politzer parameters fit based on a set of eight nitro‐aromatic molecules. In comparison with conventional quantum chemistry calculations, our approach is tremendously less computationally demanding, yet it still demonstrates competitive accuracy and predictive power.
Outcome of Segmental Gastrectomy versus Distal Gastrectomy for Early Gastric Cancer
Authors: Ishikawa Koichi , Arita Tsuyoshi , Ninomiya Shigeo , Bandoh Toshio , Shiraishi Norio , Kitano Seigo
Published: August 2007

Background

Because of the frequent occurrence of postgastrectomy disturbances after distal gastrectomy (DG), segmental gastrectomy (SG) has recently been applied to early gastric cancer (EGC). Outcomes of SG and DG in patients with EGC were compared to clarify the usefulness of SG as a treatment for EGC.

Methods

This retrospective study involved 61 patients with EGC: 28 patients who underwent DG before March 1996 and 33 patients who underwent SG after April 1996 during the period April 1991 through March 2002. Patient and tumor characteristics, operative results, and postoperative outcomes were compared between the two groups.

Results

The postoperative/preoperative body weight ratio was higher in the SG group than in the DG group. Early dumping syndrome and reflux gastritis occurred less frequently after SG than after DG. The incidence of postoperative complications was similar in the two groups. All patients remained alive without recurrence during a mean follow‐up period of 54.7 months in the SG group and 99.9 months in the DG group.

Conclusions

In comparison to DG, SG is associated with improved postoperative quality of life with no decrease in operative curability of EGC. Thus, SG is a feasible treatment for EGC.
Effects of different management regimes on aquatic macroinvertebrate diversity in Australian rice fields
Authors: Wilson A. L. , Watts R. J. , Stevens M. M.
Published: August 2007

The maintenance of invertebrate diversity within agricultural environments can enhance a number of agronomically important processes, such as nutrient cycling and biological pest control. However, few Australian studies have been undertaken which specifically address the effects of commercial management regimes on rice field biodiversity. In this study, we compared aquatic macroinvertebrate communities within Australian rice fields cultivated under three commercial management regimes: conventional‐aerial (agrochemicals applied, aerially sown), conventional‐drill (agrochemicals applied, directly drill‐sown) and organic‐drill (agrochemical‐free, directly drill‐sown). These comparisons were undertaken using a combination of community assessment approaches, including morphospecies richness, abundance, diversity and community composition. In general, greater biodiversity existed within macroinvertebrate communities that developed under organic management regimes than under conventional regimes (i.e., higher morphospecies richness and Shannon diversity). Although there were significant differences in several parameters across management regimes early in the rice‐growing season, as the growing season progressed the invertebrate communities that developed in the different management regimes became more similar. Only community composition analyses showed significant differences late in the growing season, with functional differences across aquatic faunal assemblages suggested by increased predator abundance in communities sampled from the organic management regime. In order to improve biodiversity within these aquatic environments, management techniques need to be examined individually and the most disruptive processes identified. Alternative management procedures can then be developed that minimise biodiversity loss whilst still delivering required agronomic outcomes.
Die Genetik atopischer Erkrankungen
Authors: Marenholz I. , Lee Y.-A.
Published: August 2007

Die atopischen Erkrankungen – atopische Dermatitis (AD), allergische Rhinokonjunktivitis und Asthma bronchiale – sind häufige, chronisch-entzündliche Erkrankungen der Haut und Atemwege, die oft mit Allergien (Bildung von spezifischen IgE-Antikörpern) gegen Umweltallergene assoziiert sind. Als komplexe genetische Erkrankungen werden sie sowohl durch genetische Faktoren als auch durch Umwelteinflüsse verursacht.

Bisherige Anstrengungen bei der Suche nach Krankheitsgenen zielten daher häufig auf die der Immunreaktion zugrunde liegenden Mechanismen ab. Jüngste Erfolge bei der Genidentifizierung belegen dagegen den großen Einfluss, den der epitheliale Barrieredefekt auf die Ätiologie von AD und Asthma hat. Sie stellen einen wichtigen Meilenstein bei der Aufdeckung der genetischen Ursachen dieser komplexen Erkrankungen dar und ermöglichen eine neue Sicht auf die molekularen Mechanismen, die zur Krankheitsentstehung führen. Darüber hinaus können sie wegweisend für die Entwicklung neuer Behandlungs- und Präventionsstrategien sein.
Relation of Depression, Natural Killer Cell Function, and Infections after Coronary Artery Bypass in Women
Authors: Doering Lynn V. , Martínez-Maza Otoniel , Vredevoe Donna L. , Cowan Marie J.
Published: August 2007

Background: After hospital discharge for coronary artery bypass grafting (CABG), infection is a common cause of morbidity. Although depression has been associated with immune dysfunction, its role in post-CABG infection is unknown.

Aims: The purpose of this study was to: 1) compare natural killer cell cytotoxicity (NKCC) and post-hospitalization infections in depressed and non-depressed women after CABG; and 2) test whether NKCC mediated the relationship between post-discharge depression and infections.

Methods: Sixty-seven women recovering from CABG were assessed for depression prior to hospital discharge and followed for six months. Major depression was identified by a structured clinical interview. Infections were identified by patient report using the Modified Health Review and by medical chart audit.

Results: Compared to non-depressed women after CABG, women with major depression had reduced NKCC, more all-cause infections, and more self-reported illnesses. Although NKCC did not mediate the relationship between depression and wound (i.e. incisional) infections after CABG, it did mediate the relationship between depression and non-wound infections, including pneumonias and upper respiratory infections.

Conclusions: For the first six months after CABG, women with major depression are at increased risk for infections. Natural killer cell cytotoxicity may be related to this phenomenon, particularly to non-wound infections.
Characterisation of endothelin converting enzyme‐1 shedding from endothelial cells
Authors: Kuruppu Sanjaya , Reeve Shane , Ian Smith A.
Published: August 2007

The aim of this study was to determine if endothelin converting enzyme‐1 (ECE‐1) like other members of this metalloprotease family undergoes ectodomain shedding. The release/shedding of catalytically active ECE‐1 was measured by monitoring the fluorescence resulting from the cleavage of a specific quenched fluorescent substrate. Catalytically active ECE‐1 was detected in the media of human umbilical vein endothelial cells, and was confirmed by mass spectrometry based assays. Specificity of cleavage was confirmed by using both narrow and broad specificity inhibitors. In conclusion we demonstrate and characterize for the first time, ECE‐1 shedding from the surface of endothelial cells.
Proteins of the malaria parasite sexual stages: expression, function and potential for transmission blocking strategies
Authors: PRADEL G.
Published: August 2007

The sexual phase of the malaria pathogen,Plasmodium falciparum, culminates in fertilization within the midgut of the mosquito and represents a crucial step in the completion of the parasite's life-cycle and transmission of the disease. Two decades ago, the first sexual stage-specific surface proteins were identified, among themPfs230,Pfs48/45, andPfs25, which were of scientific interest as candidates for the development of transmission blocking vaccines. A decade later, gene information gained from the sequencing of theP. falciparumgenome led to the identification of numerous additional sexual-stage proteins with antigenic properties and novel enzymes that putatively possess regulatory functions during sexual-stage development. This review aims to summarize the sexual-stage proteins identified to date, to compare their stage specificities and expression patterns and to highlight novel regulative mechanisms of sexual differentiation. The prospective candidacy of select sexual-stage proteins as targets for transmission blocking strategies will be discussed.
Cloning and characterization of an orphan seven transmembrane receptor from Schistosoma mansoni
Authors: PEARSON M. S. , McMANUS D. P. , SMYTH D. J. , JONES M. K. , SYKES A. M. , LOUKAS A.
Published: August 2007

A partial cDNA sequence was obtained from the human blood fluke, Schistosoma mansoni using a signal sequence trap approach. The full-length cDNA was cloned and termed Sm-7TM. The corresponding open reading frame had 7 membrane spanning domains and shared identity with a small, novel group of seven transmembrane (7TM) receptors from vertebrates and invertebrates, including the human ee3 receptor – a heptahelical protein implicated in neuronal signalling. Phylogenetic analysis of this novel family showed that the Sm-7TM ORF formed a clade with exclusively invertebrate sequences. Based on topology modelling with ee3, Sm-7TM was predicted to possess an intracellular C-terminal tail, which was expressed as a soluble thioredoxin fusion protein (Sm-7TMC) in Escherichia coli and purified using metal ion-affinity chromatography. A polyclonal antiserum against this domain was used to detect Sm-7TM in detergent-soluble parasite extracts and to immunolocalize the receptor to the tegument of adult S. mansoni.
Biotic and abiotic predictors of tick (Dermacentor variabilis) abundance and engorgement on free-ranging raccoons (Procyon lotor)
Authors: MONELLO R. J. , GOMPPER M. E.
Published: August 2007

We examined the relative importance of abiotic and biotic factors on the ability of adultDermacentor variabilisticks to attach and engorge with blood across 10 populations of free-ranging raccoons (Procyon lotor). We developeda priorimodels that represented explicit hypotheses based on the literature and tested the ability of these models to explain non-replete and replete (fully engorged with blood) tick infestation using generalized linear models and Akaike's Information Criterion. Abiotic models that included month and site of collection clearly provided a better fit for non-replete tick abundance data, while biotic models with host age and sex covariates best fit the replete tick data. Abiotic models of non-replete abundance were superior to biotic models because of large seasonal and site fluctuations in non-replete abundance that masked differences due to host characteristics. Conversely, best-fitting models of replete tick abundance included only age and sex and suggest that once a tick has reached a host, host-parasite interactions are the primary determinant of engorgement by female ticks. Host population structure may have a large influence on potential cohort size of ticks by reducing or increasing the total number and proportion that can become engorged and moult or lay eggs.
Bifurcations of stationary measures of random diffeomorphisms
Authors: ZMARROU HICHAM , HOMBURG ALE JAN
Published: August 2007

Random diffeomorphisms with bounded absolutely continuous noise are known to possess a finite number of stationary measures. We discuss the dependence of stationary measures on an auxiliary parameter, thus describing bifurcations of families of random diffeomorphisms. A bifurcation theory is developed under mild regularity assumptions on the diffeomorphisms and the noise distribution (e.g. smooth diffeomorphisms with uniformly distributed additive noise are included). We distinguish bifurcations where the density function of a stationary measure varies discontinuously or where the support of a stationary measure varies discontinuously. We establish that generic random diffeomorphisms are stable. The densities of stable stationary measures are shown to be smooth and to depend smoothly on an auxiliary parameter, except at bifurcation values. The bifurcation theory explains the occurrence of transients and intermittency as the main bifurcation phenomena in random diffeomorphisms. Quantitative descriptions by means of average escape times from sets as functions of the parameter are provided. Further quantitative properties are described through the speed of decay of correlations as a function of the parameter. Random differentiable maps which are not necessarily injective are studied in one dimension; we show that stable one-dimensional random maps occur open and dense and that in one-parameter families bifurcations are typically isolated. We classify codimension-one bifurcations for one-dimensional random maps; we distinguish three possible kinds, the random saddle node, the random homoclinic and the random boundary bifurcation. The theory is illustrated on families of random circle diffeomorphisms and random unimodal maps.
On the existence of non-trivial homoclinic classes
Authors: BONATTI CHRISTIAN , GAN SHAOBO , WEN LAN
Published: August 2007

We show that, for C1-generic diffeomorphisms, every chain recurrent class C that has a partially hyperbolic splitting $E^s\oplus E^c\oplus E^u$ with dimEc=1 either is an isolated hyperbolic periodic orbit, or is accumulated by non-trivial homoclinic classes. We also prove that, for C1-generic diffeomorphisms, any chain recurrent class that has a dominated splitting $E\oplus F$ with dim(E)=1 either is a homoclinic class, or the bundle E is uniformly contracting. As a corollary we prove in dimension three a conjecture of Palis, which announces that any C1-generic diffeomorphism is either Morse–Smale, or has a non-trivial homoclinic class.
Thermospheric nitric oxide at higher latitudes: Model calculations with auroral energy input
Authors: Sætre C. , Barth C. A. , Stadsnes J. , Østgaard N. , Bailey S. M. , Baker D. N. , Germany G. A. , Gjerloev J. W.
Published: August 2007

The nitric oxide (NO) density in the lower thermosphere has been calculated by a photochemical model for NOx and compared with measured NO densities from Student Nitric Oxide Explorer (SNOE). At higher latitudes the most important contributor for NO density increases is energetic electron precipitation. The electron energy is estimated in two ways, from auroral ultraviolet (UV) and X‐ray measurements obtained from Ultraviolet Imager (UVI) and Polar Ionospheric X‐ray Imaging Experiment (PIXIE) on board the Polar satellite and from ground magnetometer measurements. For the time intervals when the Polar satellite was not above the northern hemisphere, a parameterization of the electron energy flux from ground magnetic measurements was used. This parameterization was based on data from the SuperMAG database compared to UVI/PIXIE derived electron energy fluxes. The negative perturbation in the northward ground magnetic component is found to be linearly related to the precipitating electron energy flux. The 4‐day period studied is from 30 April (day 120) until 4 May 1998, where the onset of a geomagnetic storm occurred 2 May (day 122). The results of the comparisons show an overall larger modeled nitric oxide density at auroral latitudes than what was measured by SNOE. The largest discrepancies were for the day of the storm onset, when the background atmosphere was more distorted by Joule heating. The next day the agreement between the model and the observations was far better, which might be due to less amount of Joule heating this day.
Sea ice feedback and Cenozoic evolution of Antarctic climate and ice sheets
Authors: DeConto Robert , Pollard David , Harwood David
Published: August 2007

The extent and thickness of Antarctic sea ice have important climatic effects on radiation balance, energy transfer between the atmosphere and ocean, and moisture availability. This paper explores the role of sea ice and related feedbacks in the Cenozoic evolution of Antarctic climate and ice sheets, using a numerical climate model with explicit, dynamical representations of sea ice and continental ice sheets. In a scenario of decreasing Cenozoic greenhouse gas concentrations, our model initiates continental glaciation before any significant sea ice forms around the continent. Once variable ice sheets are established, seasonal sea ice distribution is highly sensitive to orbital forcing and ice sheet geometry via the ice sheet’s control on regional temperature and low‐level winds. Although the expansion of sea ice has significant climatic effects near the coast, it has only minimal effects in the continental interior and on the size of the ice sheet. Therefore the Cenozoic appearance of Antarctic sea ice was primarily a response to the growth of grounded ice sheets and was not a critical factor in episodes of Paleogene and Neogene glaciation. The influence of the East Antarctic Ice Sheet on sea ice, Southern Ocean surface temperatures, and winds has important implications for ocean circulation, the marine carbon cycle, and the development of the West Antarctic Ice Sheet. The sensitivity of sea ice to grounded ice sheets implies reconstructions of sea ice based on marine diatoms are good indicators of glacial conditions in the continental interior and may provide insight into the long‐term stability of Antarctic Ice Sheets.
Fault heterogeneity and earthquake scaling
Authors: Hetherington Alison , Steacy Sandy
Published: August 2007

There is an on‐going debate in the seismological community as to whether stress drop is independent of earthquake size and this has important implications for earthquake physics. Here we investigate this question in a simple 2D cellular automaton that includes heterogeneity. We find that when the range of heterogeneity is low, the scaling approaches that of constant stress drop. However, clear deviations from the constant stress drop model are observed when the range of heterogeneity is large. Further, fractal distributions of strength show more significant departures from constant scaling than do random ones. Additionally, sub‐sampling the data over limited magnitude ranges can give the appearance of constant stress drop even when the entire data set does not support this. Our results suggest that deviations from constant earthquake scaling are real and reflect the heterogeneity of natural fault zones, but may not provide much information about the physics of earthquakes.
Association of tropical Pacific sea surface temperatures with the stratospheric Holton‐Tan Oscillation in the Northern Hemisphere winter
Authors: Wei Ke , Chen Wen , Huang Ronghui
Published: August 2007

Based on 45 years of the European Centre for Medium Range Weather Forecasting ERA‐40 reanalysis dataset and the NOAA Extended Reconstructed sea surface temperature (SST) data, the associated anomalies in the stratospheric Holton‐Tan Oscillation (HTO) with the tropical eastern Pacific SST in the Northern Hemisphere winter are investigated. It is found that the HTO, which is induced by equatorial quasi‐biennial oscillation (QBO), is significant in the cold SST phase, but the HTO becomes much weaker in the warm SST phase. The conventional QBO modulation on the planetary wave propagation in the stratosphere is only significant when the SST anomaly is cold in the tropical eastern Pacific. However, the modulation tends to be weak when the SST anomaly is warm. It is suggested that this difference may arise from the interaction between the tropical eastern Pacific SST‐ and the QBO‐associated planetary wave propagation.
Mantle convection and magma production on present‐day Mars: Effects of temperature‐dependent rheology
Authors: Li Qingsong , Kiefer Walter S.
Published: August 2007

Using recent volcanism on Mars as an important constraint, we explore the nature of present‐day mantle convection using numerical simulations with temperature‐dependent Arrhenius viscosity. Increasing the activation energy decreases both the magma production rate and the convective heat flux, while increasing the thermal Rayleigh number increases these quantities. For values of the activation energy inferred from lab studies of olivine, a thermal Rayleigh number (defined with a volume‐averaged viscosity) exceeding 2 · 106 best fits the observational constraints, including the recent volcanism rate and the range of melt fractions in the shergottites. The heat flux out of the core is low enough to avoid a magnetic dynamo, an important improvement over prior work. These results indicate that present‐day mantle convection on Mars remains relatively vigorous.
Relaxation time effects of wave ripples on tidal beaches
Authors: Austin M. J. , Masselink G. , O'Hare T. J. , Russell P. E.
Published: August 2007

Seabed roughness due to wave ripples is a key factor in controlling sediment transport processes in the nearshore zone. Roughness is commonly considered a function of the ripple geometry, which in turn, can be predicted from sediment and hydrodynamic parameters. Existing ripple predictors consider the bed morphology to be in equilibrium with the hydrodynamics, whereas recent laboratory measurements show that the time scale for ripple development is of the order of tens of minutes to hours. Here we show that wave ripples on tidal beaches are significantly affected by relaxation time effects, with ripple height and length progressively increasing during the rising tide and remaining constant during the falling tide. Moreover, we examine the ripples in the context of existing empirical models and suggest how the temporal evolution over a tidal cycle may be predicted.
Dynamically‐based seasonal forecasts of Atlantic tropical storm activity issued in June by EUROSIP
Authors: Vitart F. , Huddleston M. R. , Déqué M. , Peake D. , Palmer T. N. , Stockdale T. N. , Davey M. K. , Ineson S. , Weisheimer A.
Published: August 2007

Most seasonal forecasts of Atlantic tropical storm numbers are produced using statistical‐empirical models. However, forecasts can also be made using numerical models which encode the laws of physics, here referred to as “dynamical models”. Based on 12 years of re‐forecasts and 2 years of real‐time forecasts, we show that the so‐called EUROSIP (EUROpean Seasonal to Inter‐annual Prediction) multi‐model ensemble of coupled ocean atmosphere models has substantial skill in probabilistic prediction of the number of Atlantic tropical storms. The EUROSIP real‐time forecasts correctly distinguished between the exceptional year of 2005 and the average hurricane year of 2006. These results have implications for the reliability of climate change predictions of tropical cyclone activity using similar dynamically‐based coupled ocean‐atmosphere models.
Multiple magnetic reconnection sites associated with a coronal mass ejection in the solar wind
Authors: Gosling J. T. , Eriksson S. , McComas D. J. , Phan T. D. , Skoug R. M.
Published: August 2007

Magnetic reconnection exhausts in the solar wind are often associated with interplanetary coronal mass ejections (ICMEs). Occasionally, an exhaust is observed at the interface between ambient solar wind and the leading edge of an ICME where reconnection serves to erode away some of the magnetic flux carried by the ICME. More often the exhausts are observed at thin current sheets within the interiors of ICMEs or near their trailing edges. We have examined an unusually large set of seven reconnection exhausts, including both sunward and antisunward directed events, observed within the interior of and near the trailing edge of an ICME. Six of these exhausts occurred as pairs on the opposite sides of relatively small magnetic filaments of locally reversed fields. For three of the exhausts the local magnetic shear was considerably less than 90°, indicating that reconnection can occur at times when the so‐called guide field component considerably exceeds the antiparallel field component. One exhaust had a local width of only 1.6 × 103 km (25.4 ion inertial lengths) and was convected past the Wind spacecraft in ∼5.4 s. No Hall field rotations were observed in association with this event, probably because of the significant guide field present and because even this extremely narrow exhaust was probably sampled well downstream (∼380 ion inertial lengths) from the reconnection site. The current sheets bounding the exhaust had widths of 3.5 and 5.2 ion inertial lengths, respectively, exceeding by several times the expected scale size of the associated diffusion region.
Linearly polarized waves with constant phase velocity in relativistic plasmas
Authors: Pesch T. C. , Kull H.-J.
Published: August 2007

The propagation of plane linearly polarized electromagnetic waves in cold plasmas at relativistic intensities is studied analytically under the assumption of a constant phase velocity. A system of coupled relativistic harmonic oscillators for the Lagrangian coordinates of the particles is derived. Based on this model, a perturbation expansion is carried out to solve the equations for small plasma densities on the one hand and nearly critical plasma densities on the other hand. In both cases fully relativistic expressions for the particle trajectories and the dispersion relations are derived. For small plasma densities the particle trajectory approaches the vacuum figure-eight orbit. For plasma densities close to the critical density a deformed circular orbit is found that differs from the commonly considered almost-transverse solution. Finally, the transition between the two classes of solutions at intermediate plasma densities is numerically investigated.
No nonlocal box is universal
Authors: Dupuis Frédéric , Gisin Nicolas , Hasidim Avinatan , Méthot André Allan , Pilpel Haran
Published: August 2007

We show that standard nonlocal boxes, also known as Popescu-Rohrlich machines, are not sufficient to simulate any nonlocal correlations that do not allow signaling. This was known in the multipartite scenario, but we extend the result to the bipartite case. We then generalize this result further by showing that no finite set containing any finite-output-alphabet nonlocal boxes can be a universal set for nonlocality.
Carrier mobility characteristics in GaInNAs dilute nitride films grown by atomic hydrogen-assisted molecular beam epitaxy
Authors: Miyashita Naoya , Shimizu Yukiko , Okada Yoshitaka
Published: August 2007

We have investigated the electrical properties of GaInNAs dilute nitride films grown by atomic hydrogen-assisted molecular beam epitaxy. We found that although the hole mobilities in Be-doped p-GaInNAs films exhibit a temperature dependence nearly identical to that for the homoepitaxial p-GaAs films, the electron mobilities in Si-doped n-GaInNAs films are strongly affected by the introduction of nitrogen into Ga(In)As. Further, the degree of scattering by the ionized impurity-like centers generated by N atoms decreased with increasing Si doping, while neutral impurity-like scattering became more dominant with increasing Si doping. These results suggest that the decrease of electron mobility and carrier concentration in Si-doped n-GaInNAs films is strongly correlated with the presence of N and Si atoms.
Single-chip pulse programmer for magnetic resonance imaging using a 32-bit microcontroller
Authors: Handa Shinya , Domalain Thierry , Kose Katsumi
Published: August 2007

A magnetic resonance imaging (MRI) pulse programmer has been developed using a single-chip microcontroller (ADμC7026). The microcontroller includes all the components required for the MRI pulse programmer: a 32-bit RISC CPU core, 62kbytes of flash memory, 8kbytes of SRAM, two 32-bit timers, four 12-bit DA converters, and 40bits of general purpose I/O. An evaluation board for the microcontroller was connected to a host personal computer (PC), an MRI transceiver, and a gradient driver using interface circuitry. Target (embedded) and host PC programs were developed to enable MRI pulse sequence generation by the microcontroller. The pulse programmer achieved a (nominal) time resolution of approximately 100ns and a minimum time delay between successive events of approximately 9μs. Imaging experiments using the pulse programmer demonstrated the effectiveness of our approach.
Enhanced microwave transmission through quasicrystal hole arrays
Authors: Papasimakis N. , Fedotov V. A. , Schwanecke A. S. , Zheludev N. I. , García de Abajo F. J.
Published: August 2007

The authors report on the observation of enhanced microwave transmission through quasiperiodic hole arrays in metal films. The fraction of transmitted light reaches 50% in a self-standing metal film and approaches 90% when the film is sandwiched between thin dielectric slabs, while the holes occupy only 10% of the sample area. The maximum transmission exhibits a Breit-Wigner resonance behavior, accompanied by zero phase change and rendering the film almost invisible over a wide frequency range. The extraordinary transmission phenomenon is interpreted in terms of resonances in the self-consistent interaction between holes, which are represented by effective electric and magnetic dipoles.
Instrument for x-ray magnetic circular dichroism measurements at high pressures
Authors: Haskel D. , Tseng Y. C. , Lang J. C. , Sinogeikin S.
Published: August 2007

An instrument has been developed for x-ray magnetic circular dichroism (XMCD) measurements at high pressures and low temperatures. This instrument couples a nonmagnetic copper-beryllium diamond anvil cell featuring perforated diamonds with a helium flow cryostat and an electromagnet. The applied pressure can be controlled in situ using a gas membrane and calibrated using Cu K-edge x-ray absorption fine structure measurements. The performance of this instrument was tested by measuring the XMCD spectra of the Gd5Si2Ge2 giant magnetocaloric material.
Touching the properties of NbTi by carbon doped tapes with mechanically alloyed MgB2
Authors: Herrmann Marko , Haessler Wolfgang , Rodig Christian , Gruner Wolfgang , Holzapfel Bernhard , Schultz Ludwig
Published: August 2007

Combining mechanical alloying and powder-in-tube processing is a promising way to obtain tapes with excellent properties. Taking advantage of the properties of nanocrystalline precursor powders, it was possible to obtain Jc values of 104A∕cm2 at 12.1T and 4.2K. Evidential substitution of carbon into the MgB2 changed the electron scattering and therefore raised the Bc2 up to 12T at 10K. Systematic investigation on the influence of the heat treatment showed that, although an interfering Fe2B reaction layer was formed, an excellent Jc of 104A∕cm2 at 14.3T and 4.2K was achieved.
Efficient deep blue emitters for organic electroluminescent devices
Authors: Ho Meng-Huan , Wu Yao-Shan , Wen Shih-Wen , Chen Teng-Ming , Chen Chin H.
Published: August 2007

Highly efficient deep blue organic light emitting devices have been fabricated with a 4-(styryl)biphenyl-core based fluorescent dopant (SK-1) in the wide band gap 2-methyl-9,10-di(1-naphthyl)anthracene (α,α-MADN) host system which achieved an electroluminescence efficiency of 5.0cd∕A and an external quantum efficiency of 4.2% at 20mA∕cm2 with a saturated blue Commission Internationale de l’Eclairage coordinates of (0.15, 0.14) and a half-decay lifetime of 8000h at an initial brightness of 100cd∕m2. The current efficiency and electroluminescent color of SK-1 doped devices have been shown to be essentially immune to drive current density.
Piezoresistor-equipped fluorescence-based cantilever probe for near-field scanning
Authors: Kan Tetsuo , Matsumoto Kiyoshi , Shimoyama Isao
Published: August 2007

Scanning near-field optical microscopes (SNOMs) with fluorescence-based probes are promising tools for evaluating the optical characteristics of nanoaperture devices used for biological investigations, and this article reports on the development of a microfabricated fluorescence-based SNOM probe with a piezoresistor. The piezoresistor was built into a two-legged root of a 160-μm-long cantilever. To improve the displacement sensitivity of the cantilever, the piezoresistor’s doped area was shallowly formed on the cantilever surface. A fluorescent bead, 500nm in diameter, was attached to the bottom of the cantilever end as a light-intensity-sensitive material in the visible-light range. The surface of the scanned sample was simply detected by the probe’s end being displaced by contact with the sample. Measuring displacements piezoresistively is advantageous because it eliminates the noise arising from the use of the optical-lever method and is free of any disturbance in the absorption or the emission spectrum of the fluorescent material at the probe tip. The displacement sensitivity was estimated to be 6.1×10−6nm−1, and the minimum measurable displacement was small enough for near-field measurement. This probe enabled clear scanning images of the light field near a 300×300nm2 aperture to be obtained in the near-field region where the tip-sample distance is much shorter than the light wavelength. This scanning result indicates that the piezoresistive way of tip-sample distance regulation is effective for characterizing nanoaperture optical devices.
Collagen-binding proteoglycan fibromodulin can determine stroma matrix structure and fluid balance in experimental carcinoma
Authors: Oldberg Åke , Kalamajski Sebastian , Salnikov Alexei V. , Stuhr Linda , Mörgelin Matthias , Reed Rolf K. , Heldin Nils-Erik , Rubin Kristofer
Published: August 2007

Research on the biology of the tumor stroma has the potential to lead to development of more effective treatment regimes enhancing the efficacy of drug-based treatment of solid malignancies. Tumor stroma is characterized by distorted blood vessels and activated connective tissue cells producing a collagen-rich matrix, which is accompanied by elevated interstitial fluid pressure (IFP), indicating a transport barrier between tumor tissue and blood. Here, we show that the collagen-binding proteoglycan fibromodulin controls stroma structure and fluid balance in experimental carcinoma. Gene ablation or inhibition of expression by anti-inflammatory agents showed that fibromodulin promoted the formation of a dense stroma and an elevated IFP. Fibromodulin-deficiency did not affect vasculature but increased the extracellular fluid volume and lowered IFP. Our data suggest that fibromodulin controls stroma matrix structure that in turn modulates fluid convection inside and out of the stroma. This finding is particularly important in relation to the demonstration that targeted modulations of the fluid balance in carcinoma can increase the response to cancer therapeutic agents.
Protection of telomeres by a conserved Stn1–Ten1 complex
Authors: Martín Victoria , Du Li-Lin , Rozenzhak Sophie , Russell Paul
Published: August 2007

Telomeres are specialized chromatin structures that protect chromosome ends. Critical among telomere proteins are those that bind the telomeric single-strand DNA (ssDNA) overhangs. These proteins are thought to differ among eukaryotes. Three interacting proteins (Cdc13, Stn1, and Ten1) associate with the telomeric overhang in budding yeast, a single protein known as Pot1 (protection of telomeres-1) performs this function in fission yeast, and a two-subunit complex consisting of POT1 and TPP1 associates with telomeric ssDNA in humans. Cdc13 and Pot1 have related oligonucleotide/oligosaccharide-binding fold (OB-fold) domains that bind the telomeric ssDNA overhang. Here we show that
Schizosaccharomyces pombe
has Stn1- and Ten1-like proteins that are essential for chromosome end protection. Stn1 orthologs exist in all species that have Pot1, whereas Ten1-like proteins can be found in all fungi. Fission yeast Stn1 and Ten1 localize at telomeres in a manner that correlates with the length of the ssDNA overhang, suggesting that they specifically associate with the telomeric ssDNA. Unlike in budding yeast, in which Cdc13, Stn1, and Ten1 all interact, fission yeast Stn1 and Ten1 associate with each other, but not with Pot1. Our findings suggest that two separate protein complexes are required for chromosome end protection in fission yeast. Structural profiling studies detect OB-fold domains in Stn1 and Ten1 orthologs, indicating that protection of telomeres by multiple proteins with OB-fold domains is conserved in eukaryotic evolution.
Spatial reduction algorithm for atmospheric chemical transport models
Authors: Rastigejev Y. , Brenner M. P. , Jacob D. J.
Published: August 2007

Numerical modeling of global atmospheric chemical dynamics presents an enormous challenge, associated with simulating hundreds of chemical species with time scales varying from milliseconds to years. Here we present an algorithm that provides a significant reduction in computational cost. Because most of the fast reactants and their quickly decomposing reaction products are localized near emission sources, we use a series of reduced chemical models of decreasing complexity with increasing distance from the source. The algorithm diagnoses the chemical dynamics on-the-run, locally and separately for every species according to its characteristic reaction time. Unlike conventional time-scale separation methods, the spatial reduction algorithm speeds up not only the chemical solver but also advection–diffusion integration. Through several examples we demonstrate that the algorithm can reduce computational cost by at least an order of magnitude for typical atmospheric chemical kinetic mechanisms.
Cultural mosaics and mental models of nature
Authors: Bang Megan , Medin Douglas L. , Atran Scott
Published: August 2007

For much of their history, the relationship between anthropology and psychology has been well captured by Robert Frost's poem, “Mending Wall,” which ends with the ironic line, “good fences make good neighbors.” The congenial fence was that anthropology studied what people think and psychology studied how people think. Recent research, however, shows that content and process cannot be neatly segregated, because cultural differences in what people think affect how people think. To achieve a deeper understanding of the relation between process and content, research must integrate the methodological insights from both anthropology and psychology. We review previous research and describe new studies in the domain of folk biology which examine the cognitive consequences of different conceptualizations of nature and the place of humans within it. The focus is on cultural differences in framework theories (epistemological orientations) among Native Americans (Menominee) and European American children and adults living in close proximity in rural Wisconsin. Our results show that epistemological orientations affect memory organization, ecological reasoning, and the perceived role of humans in nature. This research also demonstrates that cultural differences in framework theories have implications for understanding intergroup conflict over natural resources and are relevant to efforts to improve science learning, especially among Native American children.
Routine Histologic Examination is Unnecessary for Tonsillectomy or Adenoidectomy
Authors: Randall David A. , Martin Peter J. , Thompson Lester D. R.
Published: August 2007

Objective: To determine whether the current practice and incurred cost of histologic examination of tonsillectomy and adenoidectomy specimens is warranted.

Study Design: Review article based on medical literature.

Subjects and Methods: A retrospective PubMed review of all pertinent literature regarding tonsillectomy, adenoidectomy, and related surgical pathology was conducted. References of the articles obtained were reviewed for additional sources.

Results: Twenty studies report 54,901 patients and found 54 malignancies (0.087% prevalence). Of these, 48 (88% of the patients) had suspicious features such as tonsillar asymmetry, cervical lymphadenopathy, or abnormal tonsil appearance, preoperatively. The remaining six patients without any suspicious features (better representing true occult malignancy) were 0.011% of the total cases.

Conclusion: Submission of tonsillectomy, adenoidectomy, or both specimens is warranted only when patients demonstrate findings associated with malignancy: tonsillar asymmetry, history of cancer, neck mass, tonsil firmness or lesion, weight loss, and constitutional symptoms.
Incidence and Significance of Myocardial Injury After Surgical Treatment of Head and Neck Cancer
Authors: Nouraei S. A. Reza , Al‐Yaghchi Chadwan , Sandhu Guri S. , Giussani Dino A. , Doyle Patrick , Clarke Peter M.
Published: August 2007

Objective/Hypothesis: To review the incidence of, and risk factors for myocardial injury after head and neck surgery to help optimize patient care and develop perioperative cardioprotective strategies.

Study Design: Observational cohort study.

Methods: Records of 65 patients surgically treated for upper aerodigestive tract squamous cell carcinoma between 2005 and 2006 were reviewed. Information about cardiovascular history, tumor characteristics, details of surgery, and postoperative complications were recorded. Patients had troponin assays on the third postoperative day. Logistic regression was used to identify risk factors for postoperative myocardial injury.

Results: The average age at presentation was 62 ± 12 years. There were 46 (71%) males and 19 (29%) females. Troponin‐positive and ‐negative groups were matched for age, sex, cardiovascular risks, comorbidity, site, tumor‐node‐metastasis status, and duration of the operations. Sixteen (25%) patients had postoperative myocardial injury including five clinical myocardial infarctions. Factors identified as independent predictors of postoperative myocardial injury were blood pressure level (odds ratio [OR] 1.17; 95% confidence interval [CI] 1.04–1.31; P < .02), intraoperative heart rate variability (OR 1.33; 95% CI 1.04–1.71; P < .02), and the degree of postoperative inflammatory response (OR 1.07; 95% CI 1.02–1.13; P < .001).

Conclusions: Postoperative myocardial injury is a known independent predictor of cardiovascular prognosis. Its incidence in head and neck patients could potentially be reduced through stringent blood pressure management, tight intraoperative heart rate control, and dampening of the postoperative inflammatory response. Troponin testing is a valuable screening tool, and patients who have elevated levels postoperatively should be closely monitored and referred to a cardiologist for optimization of cardiovascular care.
Molecular analysis of Malassezia microflora in the lesional skin of psoriasis patients
Authors: AMAYA Misato , TAJIMA Mami , OKUBO Yukari , SUGITA Takashi , NISHIKAWA Akemi , TSUBOI Ryoji
Published: August 2007

Systemic and focal infections by microorganisms have been known to induce or exacerbate psoriasis. To investigate the role of Malassezia species in the development of psoriasis, we analyzed the Malassezia microflora in psoriasis patients using a nested polymerase chain reaction (PCR) assay, and compared it with those in atopic dermatitis (AD) patients and healthy subjects. Fungal DNA was directly collected from the lesional and non‐lesional skin of the trunk of 22 psoriasis patients by applying a transparent dressing. The extracted DNA was amplified by using specific primers designed for the PCR in the intergenic spacer or internal transcribed spacer area of the ribosomal RNA. All nine of the Malassezia species were detected at different rates from the 22 psoriasis patients. The overall detection rates in lesional and non‐lesional skin of M. restricta, M. globosa and M. sympodialis were high (96%, 82% and 64%, respectively), whereas the detection rates of the other species were relatively low. However, there was no difference in the rates between lesional and non‐lesional skin areas. The average number of Malassezia species detected in overall sites of the psoriasis patients was 3.7 ± 1.6 species, although this fact showed no correlation with the severity of the symptoms. The number of Malassezia species detected was 4.1 ± 1.9 in the AD patients, and 2.8 ± 0.8 in the healthy subjects, suggesting that the skin microflora of psoriasis patients and AD patients show greater diversity than that of healthy subjects.
Childhood bullous pemphigoid treated by i.v. immunoglobulin
Authors: XIAO Ting , LI Bo , WANG Ya‐Kun , HE Chun‐Di , CHEN Hong‐Duo
Published: August 2007

Bullous pemphigoid is an acquired autoimmune subepidermal blistering disorder mostly seen in the elderly. Childhood bullous pemphigoid is very rare. For the first time we report a case of childhood bullous pemphigoid associated with infantile eczema. Two weeks after a routine vaccination, a 3.5‐month‐old boy with infantile eczema developed a generalized blistering disorder. Histopathology revealed a subepidermal blister. Direct immunofluorescence showed linear depositions of C3 along the basement membrane zone. Indirect immunofluorescence studies demonstrated the presence of circulating immunoglobulin G antibodies directed against the epidermal side of salt‐split skin. Enzyme‐linked immunosorbent assay demonstrated serum level of anti‐BP180 antibody elevated. The patient was successfully treated by high‐dose i.v. immunoglobulin.
Juvenile systemic sclerosis: Report of three cases and review of Japanese published work
Authors: AOYAMA Kumi , NAGAI Yayoi , ENDO Yukie , ISHIKAWA Osamu
Published: August 2007

Juvenile or childhood onset systemic sclerosis (SSc) is rare. In our department, we encountered three juvenile SSc patients among the overall 206 SSc patients. All three cases were diffuse cutaneous type SSc (dSSc) with positive antinuclear antibodies. In this report, we report the three patients and analyze clinical and serological features of 58 Japanese patients with juvenile SSc. Forty‐eight patients (92.3%) were classified as dSSc and 21 out of 35 patients (60%) had anti‐topoisomelase I antibodies, while anticentromere antibodies were not detected in any patients. Prevalence of lung fibrosis and scleroderma renal crisis was low, however, the rate of cardiac involvement was higher than that in adult patients.