bluuebunny/crossref_metadata_2025 huggingface dataset:
Diagnostik und Therapie der Lungenembolie
Authors: Konstantinides
Published: September 2006

Die Diagnose und Therapie der venösen Thromboembolie war bis vor wenigen Jahren durch ein hohes Maß an Komplexität und durch fehlende Effizienz gekennzeichnet. Angesichts der unspezifischen Symptome und klinischen Befunde der akuten Lungenembolie (LE) und der multiplen Einschränkungen älterer diagnostischer Verfahren wie die Lungenszintigraphie und Pulmonalisangiographie waren für die definitive Bestätigung der Diagnose komplizierte, für die klinische Praxis ungeeignete Algorithmen erforderlich. Damit konnte bei vielen Patienten eine lebensbedrohliche Lungenembolie nicht rechtzeitig erkannt werden, während anderen Patienten aufgrund eines schlecht begründeten und dokumentierten Verdachts unnötige, potenziell gefährliche und zeitaufwändige Untersuchungen zugemutet wurden. Die Entwicklung und erfolgreiche Erprobung praxisnaher, strukturierter klinischer Modelle zur Semi-Quantifizierung der Wahrscheinlichkeit (pre-test probability) der Lungenembolie, der zunehmende Einsatz des D-Dimer-Tests bei stabilen, ambulanten Patienten und insbesondere die technische Entwicklung der Spiral-Computertomographie haben in letzter Zeit unsere diagnostische Vorgehensweise bei Lungenembolie-Verdacht wesentlich vereinfacht, beschleunigt und verbessert. Darüber hinaus wurde die pathophysiologische Bedeutung der rechtsventrikulären (RV) Dysfunktion – noch vor dem Auftreten einer klinischen Instabilität und Schocksymptomatik – erkannt, und zahlreiche Studien konnten zeigen, dass laborchemische und echokardiographische Parameter eine rechtzeitige Risikostratifizierung der Lungenembolie ermöglichen. Für die hämodynamisch stabilen Patienten ohne RV Dysfunktion (nicht-massive LE) setzen sich die niedermolekularen Heparine zunehmend als Therapie der Wahl in der Akutphase durch, während instabile Patienten mit massiver LE einer sofortigen medikamentösen (mittels Thrombolyse), operativen oder kathetertechnischen Rekanalisation bedürfen. Andererseits ist die Therapie stabiler Patienten mit RV Dysfunktion (submassive LE) derzeit noch umstritten, und die möglichen klinischen Vorteile einer frühen thrombolytischen Behandlung gegenüber einer alleinigen Heparin-Antikoagulation sollen demnächst in einer großen internationalen kontrollierten Studie überprüft werden.
Endovascular stenting of a renal transplant vein
Authors: Diehm  , Baumgartner  , Mohaupt  , Dick  , Triller  , Mahler
Published: September 2006

We describe successful endovascular stenting of a high-grade stenosis of a renal transplant vein in a 53-year old patient. Kidney transplantation had been performed due to IgA nephropathy and the patient had become symptomatic two months after uneventful recovery from operation.
Therapie der Hepatitis-B-Infektion unter der Berücksichtigung von Problemfällen
Authors: Trautwein
Published: September 2006

In den letzten Jahren konnte die Therapie der chronischen Hepatitis-B-Virus-(HBV)-Infektion kontinuierlich verbessert werden. Mittlerweile kann unter verschiedenen Therapieoptionen gewählt werden. Daher wird die Indikation und Differenzierung der Therapie anhand klinischer, biochemischer, virologischer und ggf. histologischer Befunde durchgeführt. Bei Vorliegen positiver Prognosefaktoren und Fehlen von Kontraindikationen sollte eine Therapie mit Interferon-alpha oder pegylierten Interferonen durchgeführt werden, speziell die pegylierten Interferone zeigen in aktuellen Studien relativ hohe dauerhafte Therapie-Ansprechraten. Alternativ können aktuell die oralen Nukleosid-/Nukleotidanaloga Lamivudin, Adefovir oder Entecavir eingesetzt werden. Unter Lamivudin besteht ein erhöhtes Risiko zur Selektion resistenter Virusstämme. Adefovir und Entecavir zeigen ein günstigeres Resistenzprofil, allerdings stellt die Reaktivierung nach Resistenzentwicklung bei allen Nukleosid-/Nukleotidanaloga ein grosses Problem dar. Zum jetzigen Zeitpunkt sind die Kriterien zur Beendigung einer Therapie mit Nukleosid-/Nukleotidanaloga nur unzureichend definiert. Bei Patienten mit fortgeschrittener Leberzirrhose (Child B und C) sollten ausschliesslich Nukleosid-/Nukleotidanaloga eingesetzt werden. Zukünftig könnten Kombinationstherapien die Therapie der chronischen HBV-Infektion weiter verbessern. Allerdings sollte zum jetzigen Zeitpunkt diese Therapieoption nur im Rahmen von klinischen Studien zum Einsatz kommen, da für manche der möglichen Kombinationen noch nicht feststeht, ob sich hier synergistische oder eventuell auch antagonistische Effekte ergeben.
Strategiemodell vs. Optimierungsmodell
Authors: Hünnerkopf Michael , Schneider Wolfgang , Hasselhorn Marcus
Published: September 2006

Zusammenfassung. Forschungsarbeiten zur kognitiven Entwicklungspsychologie beschäftigten sich während der letzten vier Jahrzehnte hauptsächlich damit, die Ursachen für die Verbesserung von Gedächtnisleistungen im Laufe des Grundschulalters zu finden. Dabei wurden verschiedene Faktoren wie beispielsweise der Strategieeinsatz als entscheidende Determinante der Gedächtnisentwicklung identifiziert. Neben den höheren kognitiven Prozessen wurden in alternativen Theorien allerdings auch basale Prozesse als wichtige Motoren für die Entwicklung angesehen. So etwa in der Fuzzy-Trace-Theorie, deren “Optimierungsmodell“ sich auf den Abruf von Gedächtnisinhalten aus dem Langzeitgedächtnis bezieht. Gemäß dem Optimierungsmodell ist die Erinnerungsleistung dann optimal, wenn die gelernten Items nach einem bestimmten Muster - dem so genannten Cognitive Triage Effekt - erinnert werden. In der vorliegenden Längsschnittstudie wurden Strategiemodell und Optimierungsmodell mittels einer seriellen Lernaufgabe mit akustisch dargebotenem, kategorisierbarem Material unmittelbar miteinander verglichen. Anhand einer Stichprobe von ca. 90 Kindern, deren Leistungen in den relevanten Gedächtnisaufgaben zu sieben verschiedenen Zeitpunkten erfasst wurden, ließ sich der Cognitive-Triage-Effekt in allen Klassenstufen nachweisen, zeigte sich allerdings nicht als stabiles Phänomen, das individuelle Unterschiede in der Erinnerungsleistung bedeutsam erklären kann. Demgegenüber wies der Strategieeinsatz einen engeren Zusammenhang zur Abrufleistung auf. Die Befunde legen nahe, dass der Abruf seriell dargebotener Items eher durch den Einsatz von Gedächtnisstrategien als durch basale kognitive Prozesse bedingt wird.
Wissensschema und Skript
Authors: Kopp Birgitta , Ertl Bernhard , Mandl Heinz
Published: September 2006

Zusammenfassung. Die Studie befasst sich mit der Unterstützung kooperativer Aufgabenbearbeitung in Videokonferenzen, um die Anwendung von Theoriewissen auf Aufgabenstellungen zu verbessern. Untersucht wurden die Effekte eines Wissensschemas und eines Skripts. Während das Wissensschema darauf abzielte, wichtigste Komponenten einer Aufgabe salient zu machen, stellte das Skript eine Strategie zur Aufgabenbearbeitung bereit. Wissensschema und Skript wurden als Faktoren in einem 2×2-faktoriellen Design variiert. Insgesamt nahmen 156 Lernende an der Untersuchung teil, die in Dreiergruppen eingeteilt und zufällig einer der vier Bedingungen zugeordnet wurden. Die Lernenden hatten die Aufgabe, sich individuell die Inhalte der Attributionstheorie anzueignen und im Anschluss daran dieses Theoriewissen kooperativ auf einen Fall anzuwenden. Um die Effektivität der Intervention zu erfassen, wurden neben den Ergebnissen der kooperativen Aufgabenbearbeitung auch die Ergebnisse einer individuellen Aufgabenlösung analysiert. Die Befunde zeigen einen großen Effekt für das Wissensschema hinsichtlich der kooperativen und individuellen Anwendung des Theoriewissens.
Profitiert das kindliche Sprachsystem von anderen kognitiven Entwicklungsbereichen?
Authors: Marx Edeltrud
Published: September 2006

Zusammenfassung. In der vorliegenden Pilotstudie wird untersucht, ob sich der kindliche Spracherwerb im Sinne einer Kompetenzsteigerung a) durch ein Sprachtraining oder b) durch ein Training induktiven Denkens fördern lässt. Der Nachweis von trainingsspezifischen und Transfereffekten bei Kindern zeigt folgendes Bild: Das eingesetzte Sprachtraining fördert die Dimensionen Semantik und Morphologie, nicht aber das induktive Denken. Das Training induktiven Denkens dagegen fördert sowohl die sprachlichen Leistungen als auch induktives Denken. Damit stellen sich die Leistungen des kindlichen Sprachsystems nicht nur als sensibel für sprachliche Trainings dar, sondern auch für die Förderung induktiver Strategien, wohingegen die Leistung induktiven Denkens nicht von einer sprachlichen Förderung zu profitieren vermag.
Late Neogene history of deepwater ventilation in the Southern Ocean
Authors: Hodell David A. , Venz‐Curtis Kathryn A.
Published: September 2006

We compiled carbon isotope records from the North Atlantic, South Atlantic, and Pacific oceans to estimate changes in vertical and interbasinal δ13C gradients for the last 9 Myr. Benthic δ13C values of deep water in the South Atlantic decreased in a series of steps at ∼7, 2.75, and 1.55 Ma away from the North Atlantic and toward the Pacific. The benthic δ13C of intermediate water in the South Atlantic evolved differently from deep waters, resulting in an increase in the intermediate‐to‐deep δ13C gradient (Δ13CID). The Δ13CID increased in steps at ∼2.75 and 1.55 Ma, marking the development and intensification of a chemical divide in the Atlantic Ocean between well‐ventilated intermediate water and poorly ventilated deep water. We suggest these changes in interbasinal and vertical gradients resulted from decreasing Northern Component Water and reduced ventilation of Southern Component Water (SCW). The latter was caused by several interrelated processes in Antarctic sources areas, including increased sea ice cover, enhanced surface water stratification, decreased Ekman‐induced upwelling, and reduced vertical mixing across the thermocline. Because Antarctic surface water processes and deepwater ventilation rates ultimately influence atmospheric CO2 concentration, these processes may have acted as a positive feedback that contributed to the major cooling steps in late Neogene climate.
Diurnal, semiannual, and solar cycle variations of solar wind–magnetosphere–ionosphere coupling
Authors: Nagatsuma T.
Published: September 2006

Using the Km index, the F10.7 index, and solar wind data from 1965 to 1996, we have examined the variations for the efficiency of solar wind–magnetosphere–ionosphere (SMI) coupling. It is found that the efficiency of SMI coupling depends on the total solar zenith angle, which is defined by the sum of cosine of the solar zenith angles at the northern and southern corrected geomagnetic (CGM) poles. This result suggests that the diurnal and semiannual variations of the coupling efficiency are explained by the variations of the total solar zenith angle. Further, we find that the coupling efficiency during the period of high solar activity (F10.7) tends to be lower than that during the period of low solar activity. This suggests that the efficiency of SMI coupling has a dependence on the solar activity. Our interpretation of these characteristics is that the total Pedersen conductivity on both northern and southern polar caps controls the efficiency of SMI coupling. We find that the variations of the coupling efficiency can be reproduced when our empirical conductivity model is applied in the Siscoe‐Hill model. This suggests that the ionospheric conductivity plays a significant role in SMI coupling and produces diurnal, semiannual, and solar cycle variations of geomagnetic activity.
Cohesive strengthening of fault zones during the interseismic period: An experimental study
Authors: Tenthorey Eric , Cox Stephen F.
Published: September 2006

There is widespread evidence indicating that faults regain a portion of their strength during the interseismic period. Here, we present experiments designed to understand and quantify the interseismic cohesive strengthening resulting from fluid‐rock reactions in fault zones. The triaxial experiments consisted of fracturing cores of Fontainebleau sandstone under dry conditions, forming a localized shear failure zone (stage 1). The specimens were then reacted hydrothermally under isostatic conditions, allowing the fault damage zone to compact, consolidate and strengthen (stage 2). Following reaction, the specimens were then reloaded to failure under nominally dry conditions, so that the increase in cohesive strength of the fault could be measured (stage 3). Experiments show that cohesion increase is positively correlated to temperature and pore pressure during reaction. After 6 hours of reaction at the highest temperatures (927°C) and pore pressures (200 MPa), cohesion increases by as much as 35 MPa. Microstructural examination of the specimens showed that the gouge particles within the fault compacted and cemented together, exhibiting textures typical of pressure solution and that fractures in the surrounding damage zone had healed. A theoretical treatment of the data was conducted using these experiments in combination with results on time‐dependent changes in fault cohesion presented by Tenthorey et al. (2003). We find that the rate‐controlling process in our experiments has an activation energy (Q) of approximately 70 kJ mol−1. We use this information to develop a model for time‐dependent cohesive strengthening in fault zones within the continental seismogenic regime. We conclude that significant cohesive strengthening of fault zones can occur during the interseismic period of medium to large earthquakes given the presence of reactive pore fluids.
Long‐term forecast of oceanic conditions off California and their biological implications
Authors: Auad Guillermo , Miller Arthur , Di Lorenzo Emanuele
Published: September 2006

The impact of global warming due to an increased content of atmospheric CO2 is studied by forcing a numerical eddy‐resolving ocean model with wind stresses, heat fluxes, and open boundary conditions obtained from a state‐of‐the‐art coupled model. Specifically, we have compared the 1986–1996 and 2040–2050 decades to describe and analyze the changes attained by several oceanographic variables in the California Current System. A richer atmosphere in CO2 leads to increased sea surface and near‐surface temperatures in the model domain and to an increased stratification along the coast that, however, is not strong enough to overcome the effect of increased upwelling favorable winds. A mild oceanic cooling is forecast below the 70‐m depth, in agreement with recent studies of global warming trends. Near‐surface vertical velocities increase by about 30% in April, but our simulations also forecast anomalous offshore transports in most of the coastal areas. The eddy kinetic energy decreases, on an annual mean, along the California Current main path with maximum negative anomalies in winter. The upward displacement of the 26.5 isopycnal surface, especially in the northern half of our study area, leads to an increase in the concentration of nutrients in the subsurface. The agreement between some results of this forecasting study and recent published findings would suggest that the current global warming trend would persist in the study area with similar changes to those observed over the last half century.
Postperovskite phase transition and its geophysical implications
Authors: Hirose Kei
Published: September 2006

The stability of (Mg,Fe)SiO3 perovskite in the deep lower mantle has long been uncertain. Recently, a phase transition from perovskite to postperovskite was discovered through a significant change in the X‐ray diffraction pattern at high‐pressure and high‐temperature conditions corresponding to the core‐mantle boundary region. This phase transition was also confirmed by first‐principles calculations. These suggest that (Mg,Fe)SiO3 postperovskite is the predominant mineral in the lowermost mantle called the D″ layer, and phase transition from perovskite to postperovskite has significant geophysical implications for its nature and dynamics. The postperovskite phase may account for the large seismic anomalies observed in the D″ region, such as the D″ discontinuity, S wave anisotropy, and anticorrelation between the anomalies in S wave and bulk sound velocities. In addition, this phase transition is a strongly exothermic reaction. It destabilizes the thermal boundary layer at the base of the mantle and should promote the formation of high‐temperature upwelling plumes.
Analysis of tide gauge records from the December 2004 Indian Ocean tsunami
Authors: Leonard Mark
Published: September 2006

I analyze records of the tsunami caused by the 2004 Sumatra – Andaman M9.3 earthquake from tide gauges, seismic stations and satellites, in the central Indian Ocean. I demonstrate that the tide gauge records with sampling intervals of 4 minutes or more are seriously aliased and under‐sample the tsunami waveform. Care needs to be taken when using this data for modeling this or future tsunami. The 1 minute sampling interval data accurately record the main features of the tsunami. The tsunami had significant energy at periods shorter than 1 minute and this resulted in, probably minor, aliasing of the 1 minute data. It is suggested that tide gauges intended for monitoring of tsunami use a sampling interval of at most 60 seconds, with effective anti aliasing filters being applied. Where the data is to be used for modeling at least 4 samples per minute data should be recorded.
Loki, Io: New ground‐based observations and a model describing the change from periodic overturn
Authors: Rathbun J. A. , Spencer J. R.
Published: September 2006

Loki Patera is the most powerful volcano in the solar system. We have obtained measurements of Loki's 3.5 micron brightness from NASA's Infrared Telescope Facility (IRTF) and have witnessed a major change in eruptive behavior. While Loki brightened by a factor of several every 540 days prior to 2001, from 2001 through 2004 Loki remained at a constant, intermediate brightness. We have constructed a quantitative model of Loki as a basaltic lava lake whose solidified crust overturns when it becomes buoyantly unstable. By altering the speed at which the overturn propagates across the patera, we can match our ground‐based brightness data. In addition, we can match other data taken at other times and wavelengths. By slowing the propagation speed dramatically, we can match the observations from 2001–2004. Such slowing could be due to a small change in volatile content in the lava.
Semidiurnal M2 internal tides in the Indo‐Australian Basin
Authors: Katsumata K. , Wijffels S.
Published: September 2006

Clear signals of internal tide propagation are found at the semidiurnal M2 frequency in the eastern South Indian Ocean over the abyssal plain of the Indonesian Australian Basin. We find a spatially and temporally coherent internal tide with phase propagation estimated from satellite altimetry suggesting generation along the Indonesian Archipelago and the Australian North West Shelf east of 115°E. A sinusoidal fit is used to estimate internal tide phase and amplitude along vertical cross sections from expendable bathythermograph (XBT) data along volunteer merchant shipping lines. It is likely tidal energy in the middle of the Indonesian Australian Basin is from both northern and southern source regions, and may sustain a second region of enhanced mixing for the Indonesian Throughflow.
Surface‐wave tomography from ambient seismic noise of accelerograph networks in southern Korea
Authors: Kang Tae‐Seob , Shin Jin Soo
Published: September 2006

An efficient and robust cross‐correlation technique for estimation of surface wave Green's function between two locations is applied to a set of ambient noise data recorded by accelerograph networks in the southern Korea. We have estimated 1843 group velocities of Rayleigh waves in the period band of 2–4 seconds from correlation pairs of 91 accelerograph stations. Relatively dense and uniform coverage of the pairs provides us with high‐resolution tomographic image of surface‐wave group velocities in the region. The resulting group‐velocity distribution correlates well with the characteristic features of geological map of the region, displaying low velocities for the sedimentary basins and regions of volcanic and metasedimentary rocks, and high velocities for the regions where granitoid basement rocks outcrop. The short‐period information from the accelerograph network can enhance resolution of the subsurface structures at depths within a few kilometers, which may be predominantly responsible for simulation results of strong ground motions.
A biological origin for climate signals in corals—Trace element “vital effects” are ubiquitous in Scleractinian coral skeletons
Authors: Sinclair D. J. , Williams B. , Risk M.
Published: September 2006

Laser ablation ICP/MS was used to analyze Mg, Sr and U at fine (hundreds of microns) and seasonal spatial scales in the reef coral Porites and the non‐photosynthetic “deep‐sea” corals Lophelia, Oculina, and Desmophyllum. Tropical corals display strong seasonal correlations between Mg, Sr and U, even when normal cycles are perturbed by unknown factors. An inverse relationship between Mg and U is a universal feature of all the corals, but is much larger in deep corals despite stable environmental conditions. This correlation originates from two aragonitic skeletal types: Mg‐rich opaque centers of calcification, and U‐rich large translucent crystals. The Mg‐rich material probably precipitates rapidly and corresponds to materials strongly deficient in 18O and 13C compared to isotopic equilibrium. Combined, these observations imply that varying proportions of the two skeletal types may account for most of the “temperature” or “climate” signal in tropical corals, as well as anomalous “vital effects”.
Patterns as indicators of productivity enhancement by facilitation and competition in dryland vegetation
Authors: D'Odorico Paolo , Laio Francesco , Ridolfi Luca
Published: September 2006

Well‐defined vegetation patterns are a widespread feature of dryland landscapes, where spotted, banded, or other organized systems of vegetation patches are bordered by bare soil. A number of different mechanisms have been invoked to explain the emergence of these patterns and to associate their geometrical features to the driving (biotic and abiotic) processes. A commonly accepted theory of pattern formation is based on the interplay between mechanisms of short‐range facilitation and long‐range competition with surrounding vegetation. Recently associated with the emergence of vegetation patterns, these short‐ and long‐range interactions have been seldom interpreted as a means for plants to enhance their chances of survival in arid environments. Here we develop a simplistic facilitation‐competition model to show how these spatial interactions increase the productivity of dryland ecosystems. Stable (sparsely) vegetated states are shown to occur even in systems in which unvegetated conditions are the only stable state of the local dynamics (i.e., in the absence of spatial interaction). Pattern emergence is also interpreted as an easily detectable sign of the occurrence of highly effective resource allocation and use due to spatial interactions. Moreover, the resilience of vegetated states is qualitatively related to pattern geometry.
Heme oxygenase/carbon monoxide‐biliverdin pathway down regulates neutrophil rolling, adhesion and migration in acute inflammation
Authors: Freitas A , Alves‐Filho J C , Secco D D , Neto A F , Ferreira S H , Barja‐Fidalgo C , Cunha F Q
Published: September 2006

Background and purpose:

Heme oxygenase (HO) activity is known to down‐regulate inflammatory events. Here, we address the role of HO and its metabolites, carbon monoxide (CO) and biliverdin (BVD), in leukocyte rolling, adhesion and neutrophil migration during inflammatory processes.

Experimental approach:

Intravital microscopy was used to evaluate leukocyte rolling and adhesion in the mesenteric microcirculation of mice. TNFα and IL‐1β were determined by ELISA and HO‐1 protein expression by Western blot.

Key results:

Intraperitoneal challenge with carrageenan enhanced HO‐1 protein expression in mesentery and bilirubin concentration in peritoneal exudates. Pretreatment of mice with a non‐specific inhibitor of HO (ZnDPBG) or with a HO‐1 specific inhibitor (ZnPP IX) enhanced neutrophil migration, rolling and adhesion on endothelium induced by carrageenan. In contrast, HO substrate (hemin), CO donor (DMDC) or BVD reduced these parameters. The reduction of neutrophil recruitment promoted by HO metabolites was independent of the production of chemotactic cytokines. Inhibitory effects of CO, but not of BVD, were counteracted by treatment with a soluble guanylate cyclase (sGC) inhibitor, ODQ. Furthermore, inhibition of HO prevented the inhibitory effect of a nitric oxide (NO) donor (SNAP) upon neutrophil migration, while the blockade of NO synthase (NOS) activity by aminoguanidine did not affect the CO or BVD effects.

Conclusions and Implications:

Metabolites of HO decreased leukocyte rolling, adhesion and neutrophil migration to the inflammatory site by a mechanism partially dependent on sGC. Moreover, inhibition by NO of neutrophil migration was dependent on HO activity.

British Journal of Pharmacology(2006)149, 345–354. doi:10.1038/sj.bjp.0706882
Opposite diastereoselective activation of P2Y1 and P2Y11 nucleotide receptors by adenosine 5′‐O‐(α‐boranotriphosphate) analogues
Authors: Ecke D , Tulapurkar M E , Nahum V , Fischer B , Reiser G
Published: September 2006

Background and purpose:

We explored the stereoselective activation of the P2Y11 receptor, stably expressed and tagged with GFP, in 1321N1 cells, in comparison to its closest homologue, the P2Y1 receptor.

Experimental approach:

The potency of several chiral ATP analogues was determined by measuring increases in intracellular calcium concentration ([Ca2+]i). In a series of ATP‐α‐B and ATP‐α‐S analogues, a non‐bridging oxygen atom of P was substituted by BH3 or sulphur, respectively, introducing a chiral center at P. The pairs of diastereoisomers (A and B isomers) were each applied as purified compounds.

Key results:

The (B) isomers (ATP‐α‐B Sp isomers and ATP‐α‐S Rp isomers) of all derivatives tested were more potent at the P2Y11 receptor than the corresponding (A) isomers (ATP‐α‐B Rp isomers and ATP‐α‐S Sp isomers) and the parent compounds. This characteristic of the P2Y11 receptor is opposite to the behaviour of the same diastereoisomers at the P2Y1 receptor, at which the (A) isomers are more active.

Conclusions and implications:

The distinctly opposite diastereoselective activity of ATP derivatives at the P2Y11 and the P2Y1 receptor will allow the deciphering of structural differences of the ligand recognition sites between these receptor subtypes and may aid in the development of subtype‐selective agonists. Moreover, ATP‐α‐B diastereoisomers are not active at the P2Y2 receptor. Thus, they are compounds suitable for distinguishing the functional contribution of the two ATP‐activated P2Y receptors, the P2Y2 and P2Y11 receptor, in physiological or pathophysiological responses of cells.

British Journal of Pharmacology (2006) 149, 416–423. doi:10.1038/sj.bjp.0706887
Inside the brain of a neuron
Authors: Sidiropoulou Kyriaki , Pissadaki Eleftheria Kyriaki , Poirazi Panayiota
Published: September 2006

For many decades, neurons were considered to be the elementary computational units of the brain and were assumed to summate incoming signals and elicit action potentials only in response to suprathreshold stimuli. Although modelling studies predicted that single neurons constitute a much more powerful computational entity, able to perform an array of nonlinear calculations, this possibility was not explored experimentally until the discovery of active mechanisms in the dendrites of most neuron types. Here, we review several modelling studies that have addressed information processing in single neurons, starting with those characterizing the arithmetic of different dendritic components, to those tackling neuronal integration at the cell body and, finally, those analysing the computational abilities of the axon. We present modelling predictions along with supporting experimental data in an effort to highlight the significant contribution of modelling work to enhancing our understanding of single‐neuron arithmetic.
The Mind or the Heart? it Depends on the (definition of) Situation
Authors: Ciborra Claudio , Willcocks Leslie
Published: September 2006

This paper1 establishes the importance of situatedness of experience in Information Systems (IS) studies, but also critiques the limited notion of situatedness all too frequently employed. In the original language of phenomenology as used by Heidegger, ‘Befindlichkeif means not just ‘state of mind’ but also refers to disposition, mood, affectedness and emotion. The paper reviews the controversies in the literature generated by opponents to the situatedness literature and provides two case studies to show how current IS uses of the situatedness perspectives differ from the original one. From this discussion, the paper argues that the limited IS research agendas on situated action found in Al, cognitive and social sciences need to capture the inner life of the actor, mind and heart, through the scope of a renewed, authentic, phenomenological tradition.
Optical determination of three-dimensional nanotrack profiles generated by single swift-heavy ion impacts in lithium niobate
Authors: Olivares J. , García-Navarro A. , García G. , Mýndez A. , Agulló-López F.
Published: September 2006

Three-dimensional (3D) profiles of single nanotracks generated by a low impact density of Cl ions at 46MeV have been determined by optical methods, using an effective-medium approach. The buried location of the maximum stopping power induces a surface optical waveguiding layer even at ultralow fluences (1011–1013at.∕cm2) that allows to obtain the effective refractive index profiles (from dark-mode measurements). Combining the optical information with Rutherford backscattering spectroscopy/channeling experiments, the existence of a surrounding defective halo around the amorphous track core has been ascertained. The 3D profile of the halo has also been determined.
Gas phase electronic spectra of the carbon chains C5, C6, C8, and C9
Authors: Boguslavskiy A. E. , Maier J. P.
Published: September 2006

Three electronic absorption systems for C5 at 511, 445, and 232nm and one for C6, C8, and C9 centered at 228, 259, and 288nm have been observed in the gas phase. The C5 chain was produced in both discharge and ablation sources and detected using resonant two-color two-photon ionization spectroscopy involving 10.5eV photons. The decay of the excited singlet electronic states indicates fast intramolecular processes on a subpicosecond time scale. The internal energy is assumed to be trapped in a triplet state for at least 15μs. Hole-burning experiments on the 2Σu−3←XΣg−3 transition of C6, C8, and Σu+1←XΣg+1 of C9 confirm the predissociative nature of the excited electronic states.
Direct measurement of composition of buried quantum dots using aberration-corrected scanning transmission electron microscopy
Authors: Wang P. , Bleloch A. L. , Falke M. , Goodhew P. J. , Ng J. , Missous M.
Published: September 2006

The authors present a direct method to quantitatively measure the indium composition of buried InAs quantum dots embedded in a GaAs matrix. In this method, spatially resolved electron-energy-loss spectroscopy combined with aberration-corrected scanning transmission electron microscopy at atomic resolution was employed to measure compositional profiles across the center of a quantum dot and the adjacent wetting layer. The size and shape of the quantum dots were determined using the Z contrast in high angle annular dark field images. A substantial enrichment in indium at the top of the quantum dots was identified, which is consistent with theoretical predictions.
Tunable electromagnetic noise suppressor integrated with a magnetic thin film
Authors: Sohn Jaecheon , Han S. H. , Yamaguchi M. , Lim S. H.
Published: September 2006

A tunable electromagnetic noise suppressor based on a coplanar waveguide transmission line integrated with a magnetic thin film is presented. High resonance frequencies (above 10GHz) and good signal attenuation characteristics are observed in the device, making it suitable for high frequency noise suppressors. The main mechanism of the loss generation is found to be the L-C resonance, not ferromagnetic resonance observed in previous similar devices. With the inclusion of a magnetic material, the resonance frequency can be tuned during the operation with an applied magnetic field.
Search for suitable approximation methods for fullerene structure and relative stability studies: Case study with C50
Authors: Tian Wei Quan , Feng Ji-Kang , Wang Yan Alexander , Aoki Yuriko
Published: September 2006

Local density approximation (LDA), several popular general gradient approximation (GGA), hybrid module based density functional theoretical methods: SVWN, BLYP, PBE, HCTH, B3LYP, PBE1PBE, B1LYP, and BHandHLYP, and some nonstandard hybrid methods are applied in geometry prediction for C60 and C70. HCTH with 3-21G basis set is found to be one of the best methods for fullerene structural prediction. In the predictions of relative stability of C50 isomers, PM3 is an efficient method in the first step for sorting out the most stable isomers. HCTH with 3-21G predicts very good geometries for C50, similar to the performance of B3LYP∕6−31G(d). The gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital from the predictions of all the density functional theory methods has the following descending order: Egap(half-and-halfhybrid)>Egap(B3LYP)>Egap(HCTH)(GGA)>Egap(SVWN)(LDA).
A restricted-open-shell complete-basis-set model chemistry
Authors: Wood Geoffrey P. F. , Radom Leo , Petersson George A. , Barnes Ericka C. , Frisch Michael J. , Montgomery John A.
Published: September 2006

A restricted-open-shell model chemistry based on the complete basis set-quadratic Becke3 (CBS-QB3) model is formulated and denoted ROCBS-QB3. As the name implies, this method uses spin-restricted wave functions, both for the direct calculations of the various components of the electronic energy and for extrapolating the correlation energy to the complete-basis-set limit. These modifications eliminate the need for empirical corrections that are incorporated in standard CBS-QB3 to compensate for spin contamination when spin-unrestricted wave functions are used. We employ an initial test set of 19 severely spin-contaminated species including doublet radicals and both singlet and triplet biradicals. The mean absolute deviation (MAD) from experiment for the new ROCBS-QB3 model (3.6±1.5kJmol−1) is slightly smaller than that of the standard unrestricted CBS-QB3 version (4.8±1.5kJmol−1) and substantially smaller than the MAD for the unrestricted CBS-QB3 before inclusion of the spin correction (16.1±1.5kJmol−1). However, when applied to calculate the heats of formation at 298K for the moderately spin-contaminated radicals in the G2/97 test set, ROCBS-QB3 does not perform quite as well as the standard unrestricted CBS-QB3, with a MAD from experiment of 3.8±1.6kJmol−1 (compared with 2.9±1.6kJmol−1 for standard CBS-QB3). ROCBS-QB3 performs marginally better than standard CBS-QB3 for the G2/97 set of ionization energies with a MAD of 4.1±0.1kJmol−1 (compared with 4.4±0.1kJmol−1) and electron affinities with a MAD of 3.9±0.2kJmol−1 (compared with 4.3±0.2kJmol−1), but the differences in MAD values are comparable to the experimental uncertainties. Our overall conclusion is that ROCBS-QB3 eliminates the spin correction in standard CBS-QB3 with no loss in accuracy.
Red-light-emitting diodes fabricated by near-ultraviolet InGaN chips with molybdate phosphors
Authors: Wang Zhengliang , Liang Hongbin , Wang Jing , Gong Menglian , Su Qiang
Published: September 2006

Phosphors Na5La(MoO4)4:xEu3+ and NaEu(MoO4)2 were prepared with a solid-state reaction technique. Their photoluminescent properties were investigated at room temperature. Bright red-light-emitting diodes were fabricated by coating the phosphors onto near-ultraviolet/violet-emitting InGaN chips, respectively. The diodes prepared with phosphor Na5Eu(MoO4)4 show appropriate CIE chromaticity coordinates (x=0.65,y=0.34) and exhibit more intensive red emission than that prepared with NaEu(MoO4)2, indicating that Na5Eu(MoO4)4 may be applied as an excellent red component for near-ultraviolet InGaN-based white diodes.
Compact X-pinch based point x-ray source for phase contrast imaging of inertial confinement fusion capsules
Authors: Beg F. N. , Stephens R. B. , Xu H.-W. , Haas D. , Eddinger S. , Tynan G. , Shipton E. , DeBono B. , Wagshal K.
Published: September 2006

Results from experiments performed to characterize plastic capsules containing foam layers are presented. A compact X-pinch pulser with a footprint <1m2 having a peak current of 80kA and a rise time of 50ns was used. Various wire materials including tungsten, molybdenum, and aluminum were employed. Results with plastic capsules (1mm diameter, 20μm thick wall with 80μm foam inside the capsule) show phase contrast effects at the edges of the wall due to the foam, which mimics the ice inside the shell. The sharpness of the image reveals a source less than 2μm in size and x-ray diodes show a pulse length of ∼10ns. The small source size allows high-resolution phase contrast imaging of capsules. The x-ray pulse from an X-pinch is sufficiently short to avoid the motional blurring due to cryogenic system vibrations, which is not possible with low flux sources.
Hydrogen bonding in liquid and supercritical 1-octanol and 2-octanol assessed by near and midinfrared spectroscopy
Authors: Palombo F. , Tassaing T. , Danten Y. , Besnard M.
Published: September 2006

The near and midinfrared spectra of 1-octanol (and 2-octanol) have been measured along the liquid-gas coexistence curve from room temperature up to the critical point and in the supercritical domain along the isotherm T=385°C (and T=365°C) above the critical point of both 1-octanol and 2-octanol for pressure ranging from 0.5 up to 15MPa. The density values of SC 1- and 2-octanol have been estimated by analysing the near infrared (NIR) spectra in the 3νa(CH) region. A quantitative analysis of the absorption band associated with the OH stretching vibration [ν(OH)] and its first and second overtones [2ν(OH) and 3ν(OH)] was carried out in order to estimate the percentage of “free” OH groups in both alcohols in the whole thermodynamic domain investigated here. Very consistent results have been obtained from the independent analysis of these three different absorption bands which gave us a good confidence in the degree of hydrogen bonding reported here for 1- and 2-octanol. Thus, the percentage of free OH groups which is around 5% in liquid 1-octanol under ambient conditions strongly increase up to 70%–80% at a temperature of about 340°C. Then, in the supercritical domain, upon a decrease of the density from 0.4to0.1gcm−3, the fraction of free hydroxyl groups is nearly constant presenting a plateaulike regime around 80%. As the density decreases again, this plateau regime is followed by a further increase of Xnb which reaches a value of 96% for the system in the gaseous phase (0.01gcm−3; P=0.45MPa). Finally, it comes out from this study that the percentage of free OH groups is always greater in 2-octanol than in 1-octanol at the same density.
Photodissociation of Mg+–XCH3 (X=F, Cl, Br, and I) complexes. II. Fragment angular and energy distributions
Authors: Furuya Ari , Misaizu Fuminori , Ohno Koichi
Published: September 2006

Angular and energy distributions of photofragments from Mg+–XCH3 (X=F, Cl, Br, and I) were deduced from time-of-flight (TOF) profiles measured by rotating the polarization direction of the dissociation laser with respect to ion beam direction. The TOF profiles of ICH3+ and MgI+ fragment ions produced from Mg+–ICH3 complex with 266 and 355nm photons showed clear but opposite recoil anisotropy to each other. In addition, BrCH3+ formed by a dissociation of the Mg+–BrCH3 complex at a photolysis wavelength of 266nm also showed an anisotropic distribution in the TOF profile which had the same behavior as the profile of ICH3+. For Mg+–FCH3 complex, CH3+ and MgF+ formed with a 266nm photon had also spatial anisotropy, in which the TOF profile of MgF+ was almost opposite to that of MgI+. These anisotropic distributions were explained by (1) local excitation on the Mg+ ion, (2) rapid dissociation compared with a rotational period of the parent complex, and (3) geometrical structures of the parent complexes. Anisotropy β parameter values were determined to be +1.30(ICH3+), −0.50(MgI+), +0.74(BrCH3+), and +0.75(CH3+ and MgF+). This dependence on the halogen atom observed in β values was qualitatively explained by both the geometrical parameters and classical rotational periods of parent complexes. In the product energy distribution, 46%, 40%, 21%, 16%, and 16% of available energies were found to be transferred into translational energies of ICH3+, MgI+, BrCH3+, CH3+, and MgF+, respectively. These values were compared with energy distributions estimated by a statistical prior distribution and a nonstatistical impulsive model. For ICH3+ and MgI+, the translational energies determined from the measurement had values between those estimated from statistical and nonstatistical models. On the other hand, the energy partitioning for the product ions of BrCH3+, CH3+, and MgF+ was found to be almost statistical. From these considerations, we concluded that nonstatistical processes were more important in the dissociation of Mg+–ICH3 than in other systems.
Proton radiation hardness of single-nanowire transistors using robust organic gate nanodielectrics
Authors: Ju Sanghyun , Lee Kangho , Janes David B. , Dwivedi Ramesh C. , Baffour-Awuah Habibah , Wilkins R. , Yoon Myung-Han , Facchetti Antonio , Mark Tobin J.
Published: September 2006

In this contribution, the radiation tolerance of single ZnO nanowire field-effect transistors (NW-FETs) fabricated with a self-assembled superlattice (SAS) gate insulator is investigated and compared with that of ZnO NW-FETs fabricated with a 60nm SiO2 gate insulator. A total-radiation dose study was performed using 10MeV protons at doses of 5.71 and 285krad(Si). The threshold voltage (Vth) of the SAS-based ZnO NW-FETs is not shifted significantly following irradiation at these doses. In contrast, Vth parameters of the SiO2-based ZnO NW-FETs display average shifts of ∼−4.0 and ∼−10.9V for 5.71 and 285krad(Si) H+ irradiation, respectively. In addition, little change is observed in the subthreshold characteristics (off current, subthreshold slope) of the SAS-based ZnO NW-FETs following H+ irradiation. These results strongly argue that the bulk oxide trap density and interface trap density formed within the SAS and/or at the SAS-ZnO NW interface during H+ irradiation are significantly lower than those for the corresponding SiO2 gate dielectrics. The radiation-robust SAS-based ZnO NW-FETs are thus promising candidates for future space-based applications in electronics and flexible displays.
Photoluminescence and multiphonon resonant Raman scattering in low-temperature grown ZnO nanostructures
Authors: Kumar Bhupendra , Gong Hao , Chow Shue Yin , Tripathy Sudhiranjan , Hua Younan
Published: September 2006

The authors report on the optical properties of nanocrystalline ZnO grown at 200°C by radio-frequency magnetron sputtering. The nanocrystalline nature of the films was confirmed by cross-sectional transmission electron microscopy. In these films, ZnO nanocrystals with an average size of about 3–5nm were embedded in an amorphous matrix. The photoluminescence spectra from such nanostructured thin films show the near-band-edge emissions around 3.3eV. A redshift of about 8–11cm−1 is observed in the case of first-order longitudinal-optical (LO) phonon of ZnO in such nanostructures when compared to the LO phonon peak of bulk ZnO. The ultraviolet resonant Raman excitation at 77K shows multiphonon LO modes up to eighth order.
Nonlocality-controlled interaction of spatial solitons in nematic liquid crystals
Authors: Hu Wei , Zhang Tao , Guo Qi , Xuan Li , Lan Sheng
Published: September 2006

The authors demonstrate experimentally that interaction between nonlocal solitons in nematic liquid crystals (NLCs) can be controlled by the degree of nonlocality. For a given beam width, the degree of nonlocality can be modulated by changing the pretilt angle θ0 of NLC molecules through bias voltage V. As V increases (so does θ0), the degree of nonlocality decreases. When the degree of nonlocality is below a critical value, the solitons behave in the way like their local counterpart, i.e., in-phase solitons attract while out-of-phase solitons repulse each other. Such a voltage-controlled interaction between the solitons can be readily implemented in experiments.
Dynamic behavior and phase transition of magic Al clusters on Si(111)-7×7 surfaces
Authors: Li Run-Wei , Owen J. H. G. , Kusano S. , Miki K.
Published: September 2006

By means of high-temperature scanning tunneling microscopy, the authors present a direct observation on the dynamic behavior and phase transition of magic Al clusters on Si(111)-7×7 surfaces at high temperature. When the temperature is above 500°C, fast diffusion of magic Al clusters on Si(111)-7×7 surfaces occurs while the magic cluster phase transforms into √3×√3-Al phase on downterraces (the downstep side of a terrace). From an Arrhenius plot, the activation energy of magic Al clusters on Si(111)-7×7 surfaces was extracted to be 2.0±0.3eV. This study supplies important information for understanding the formation and phase transition process of magic Al nanoclusters on Si(111)-7×7 surfaces.
Surface morphologies of homoepitaxial ZnO on Zn- and O-polar substrates by plasma assisted molecular beam epitaxy
Authors: Xu Huaizhe , Ohtani K. , Yamao M. , Ohno H.
Published: September 2006

Homoepitaxial ZnO layers are grown on Zn-polar (0001) and O-polar (0001¯) surfaces of single crystal ZnO substrates by plasma assisted molecular beam epitaxy. It is found that the growth conditions to obtain smooth surfaces are significantly different for the two surface polarities. For growth on Zn-polar surface, moderate temperature (650°C) and highly O-rich condition (low Zn∕O2) are required, while high temperature (1000–1050°C) and Zn-rich condition (high Zn∕O2 ratio) are essential for growth on O-polar surfaces.
Local epitaxial growth of aluminum nitride and molybdenum thin films in fiber texture using aluminum nitride interlayer
Authors: Kamohara Toshihiro , Akiyama Morito , Ueno Naohiro , Nonaka Kazuhiro , Kuwano Noriyuki
Published: September 2006

The authors have found the local epitaxial growth of aluminum nitride (AlN) and molybdenum (Mo) films in fiber texture, although the interface between the AlN and Mo films has different crystal symmetries. The local heteroepitaxial relationship is (0001)AlN[21¯1¯0]‖(110)Mo[1¯11]‖(0001)AlN[21¯1¯0]. The AlN films changes from nonequiaxed microstructures to equiaxed columnar structures. The authors think that the AlN interlayer is effective in decreasing the crystallization energy of the Mo electrode due to the coherent heteroepitaxial nucleation. It is interesting that the local heteroepitaxial relationship does not satisfy the criteria for heteroepitaxial growth.
Role of monomer packing fraction in rubber elasticity
Authors: Bower Allan F. , Weiner Jerome H.
Published: September 2006

In a recent paper [A. F. Bower and J. H. Weiner, J. Chem. Phys. 120, 11948 (2004)] we presented an extensive set of molecular dynamic simulations that examined the effects of confining pressure on the deviatoric stress-v-stretch behavior of a model rubber. In this note, we reconsider the implications of these data on the behavior of rubber under standard conditions. It is shown that simulations with realistic packing fractions predict stresses that are substantially larger than the predictions of the classical affine network model of rubber elasticity, suggesting that nonbonded interactions contribute significantly to the deviatoric stress even at standard conditions.