Width and Magnetic Field Dependence of Transition Temperature in Ultranarrow Superconducting Wires

We calculate the transition temperature in ultranarrow superconducting wires as a function of wire width, resistance and applied magnetic field. We compare the results of first-order perturbation theory and the non-perturbative resummation technique developed by Oreg and Finkel'stein. The latter technique is found to be superior as it is valid even in the strong disorder limit. In both cases the predicted additional suppression of the transition temperature due to the reduced dimensionality is strongly dependent upon the boundary conditions used. When we use the correct (zero-gradient) boundary conditions, we find that theory and experiment are consistent, although more experimental data is required to verify this systematically. We calculate the magnetic field dependence of the transition temperature for different wire widths and resistances in the hope that this will be measured in future experiments. The predicted results have a rich structure - in particular we find a dimensional crossover which can be tuned by varying either the width of the wire or its resistance per square.Comment: 12 pages, 1 table, 7 figures. The changes made to the paper are ones of emphasis. The comparison between theory and experiment has been altered, and detailed comparisons of various approximations have been omitted, although the results are summarised in the paper. Much more emphasis has been placed on the new predictions of the effect of an applied magnetic field on transition temperature in wires (Figs. 5-7

Development of a suitable detection method for silver nanoparticles in fish tissue using single particle ICP-MS

A strong alkali extraction technique and suitable single particle ICP-MS method is described for the routine quantifying of particle number concentration, particle size and particle mass concentration for silver nanomaterials in fish tissue.</p

Tetragonal Diiodotetrapyridinedicopper(I): Structure, Luminescence, and Computational Modeling

We report on a new crystal modification of (CuIPy2) n (Py = pyridine), a compound first reported by White et al. In contrast to White’s orthorhombic structure, which is comprised of rhomboid iodide-bridged dimers, Cu2I2Py4, our new tetragonal crystal structure in space group P41212 is disordered and can be interpreted as either iodide-bridged dimers or helical chains. To determine the structure type, variable temperature X-ray diffraction and luminescence measurements were carried out. The photoluminescence spectrum shows a distinct cluster-centered transition at high excitation energies which is consistent with the dimer structure. DFT and TD-DFT calculations were performed to explain the difference between the emission spectrum at high energies compared to low energies. Furthermore, correlation of the luminescence spectrum with the X-ray results as temperature is varied demonstrates that the cluster-centered luminescence band in Cu2I2Py4 arises from close Cu⋯Cu distances which vary with temperature. A low temperature X-ray crystallographic redetermination of the cubane tetrameric Cu4I4Py4 is also presented. Both Cu2I2Py4 and Cu4I4Py4 structures show distortion of the Cu n I n core cluster at low temperature resulting in reduced Cu⋯Cu distances, but with I⋯I distances roughly unchanged

Development of a method for the determination of ultra-trace level mercury in adipose tissue by cold vapour atomic fluorescence spectrometry

A method for the determination of total mercury in rat adipose tissue by cold vapour atomic fluorescence spectrometry (CVAFS) has been developed. Adipose samples were initially subjected to a lyophilization procedure in order to facilitate the homogenization and accurate weighing of small tissue aliquots (~50 mg). A closed vessel microwave digestion procedure using a mixture of sulphuric and nitric acids was used to liberate mercury from the adipose matrix. All mercury species were quantitatively oxidized to Hg(II) by a potassium bromate/bromide oxidation, then reduced to Hg(0) vapour by stannous chloride prior to fluorescence detection. The CVAFS exhibited a linear range of 10 pg Hg/ml to 120 pg Hg/ml. The method detection limit in solution was 2 pg Hg/ml, or 1 ng Hg/g adipose tissue, based on a nominal 50 mg sample and a final volume of 25 ml. A reference material from the National Research Council of Canada (DOLT-2, trace metals in dogfish liver) was prepared in quadruplicate in order to assess the accuracy and precision of the method. Mercury in this material was recovered at 2.22 ± 0.08 μ g/g, which is 104% of the certified level (2.14 ± 0.10 μ g/g)

SensorWeb Evolution Using the Earth Observing One (EO-1) Satellite as a Test Platform

The Earth Observing One (EO-1) satellite was launched in November 2000 as a one year technology demonstration mission for a variety of space technologies. After the first year, in addition to collecting science data from its instruments, the EO-1 mission has been used as a testbed for a variety of technologies which provide various automation capabilities and which have been used as a pathfinder for the creation of SensorWebs. A SensorWeb is the integration of variety of space, airborne and ground sensors into a loosely coupled collaborative sensor system that automatically provides useful data products. Typically, a SensorWeb is comprised of heterogeneous sensors tied together with a messaging architecture and web services. This paper provides an overview of the various technologies that were tested and eventually folded into normal operations. As these technologies were folded in, the nature of operations transformed. The SensorWeb software enables easy connectivity for collaboration with sensors, but the side benefit is that it improved the EO-1 operational efficiency. This paper presents the various phases of EO-1 operation over the past 12 years and also presents operational efficiency gains demonstrated by some metrics

The Northwest Tropical Atlantic Station (NTAS) : NTAS-1 mooring deployment cruise report

A surface mooring outfitted for meteorological and oceanographic measurement was deployed near 14°50'N, 51°00'W in the northwest tropical Atlantic on 30 March 2001. This was the initial deployment of the Northwest Tropical Atlantic Station (NTAS) project for air–sea flux measurement. These observations will be used to investigate air–sea interaction processes related to climate variability. The deployment was done on R/V Oceanus Cruise 365, Leg 5 by the Upper Ocean Processes Group (UOP) of the Woods Hole Oceanographic Institution. The 3-meter discus buoy was outfitted with two Air–Sea Interaction Meteorology (ASIMET) systems. Each system measures, records, and transmits via Argos satellite the surface meteorological variables necessary to compute air–sea fluxes of heat, moisture and momentum. The upper 120 m of the mooring line was outfitted with oceanographic sensors for the measurement of temperature and velocity. This report describes the initial deployment of the NTAS mooring (NTAS-1), including some of the pre-cruise buoy preparations and post cruise data comparisons.Funding was provided by the National Oceanic and Atmospheric Administration (NOAA) through the Cooperative Institute for Climate and Ocean Research (CICOR) under Grant No. NA87RJ0445

The Namibia Early Flood Warning System, A CEOS Pilot Project

Over the past year few years, an international collaboration has developed a pilot project under the auspices of Committee on Earth Observation Satellite (CEOS) Disasters team. The overall team consists of civilian satellite agencies. For this pilot effort, the development team consists of NASA, Canadian Space Agency, Univ. of Maryland, Univ. of Colorado, Univ. of Oklahoma, Ukraine Space Research Institute and Joint Research Center(JRC) for European Commission. This development team collaborates with regional , national and international agencies to deliver end-to-end disaster coverage. In particular, the team in collaborating on this effort with the Namibia Department of Hydrology to begin in Namibia . However, the ultimate goal is to expand the functionality to provide early warning over the South Africa region. The initial collaboration was initiated by United Nations Office of Outer Space Affairs and CEOS Working Group for Information Systems and Services (WGISS). The initial driver was to demonstrate international interoperability using various space agency sensors and models along with regional in-situ ground sensors. In 2010, the team created a preliminary semi-manual system to demonstrate moving and combining key data streams and delivering the data to the Namibia Department of Hydrology during their flood season which typically is January through April. In this pilot, a variety of moderate resolution and high resolution satellite flood imagery was rapidly delivered and used in conjunction with flood predictive models in Namibia. This was collected in conjunction with ground measurements and was used to examine how to create a customized flood early warning system. During the first year, the team made use of SensorWeb technology to gather various sensor data which was used to monitor flood waves traveling down basins originating in Angola, but eventually flooding villages in Namibia. The team made use of standardized interfaces such as those articulated under the Open Cloud Consortium (OGC) Sensor Web Enablement (SWE) set of web services was good [1][2]. However, it was discovered that in order to make a system like this functional, there were many performance issues. Data sets were large and located in a variety of location behind firewalls and had to be accessed across open networks, so security was an issue. Furthermore, the network access acted as bottleneck to transfer map products to where they are needed. Finally, during disasters, many users and computer processes act in parallel and thus it was very easy to overload the single string of computers stitched together in a virtual system that was initially developed. To address some of these performance issues, the team partnered with the Open Cloud Consortium (OCC) who supplied a Computation Cloud located at the University of Illinois at Chicago and some manpower to administer this Cloud. The Flood SensorWeb [3] system was interfaced to the Cloud to provide a high performance user interface and product development engine. Figure 1 shows the functional diagram of the Flood SensorWeb. Figure 2 shows some of the functionality of the Computation Cloud that was integrated. A significant portion of the original system was ported to the Cloud and during the past year, technical issues were resolved which included web access to the Cloud, security over the open Internet, beginning experiments on how to handle surge capacity by using the virtual machines in the cloud in parallel, using tiling techniques to render large data sets as layers on map, interfaces to allow user to customize the data processing/product chain and other performance enhancing techniques. The conclusion reached from the effort and this presentation is that defining the interoperability standards in a small fraction of the work. For example, once open web service standards were defined, many users could not make use of the standards due to security restrictions. Furthermore, once an interoperable sysm is functional, then a surge of users can render a system unusable, especially in the disaster domain

Early Miocene tectono-sedimentary shift in the eastern North Alpine Foreland Basin and its relation to changes in tectonic style in the Eastern Alps

A striking difference along the Alpine Orogen is the style of collisional tectonics during the Oligo-Miocene, with the onset of escape tectonics in the Eastern Alps (Fig. 1A). The indentation of the Adriatic Plate into the Eastern Alpine Orogen resulted in the formation of conjugate dextral and sinistral strike-slip faults in the vicinity of the Tauern Window. Moreover, major changes occurred in the foreland of the Eastern and Southern Alps in the Early Miocene, with the cessation of the northern Alpine front propagation and the onset of thrusting along the Southern Alpine Front. In this study, we present new results from structural, stratigraphic and subsidence analyses of the eastern North Alpine Foreland Basin (NAFB; Fig. 1B) as part of the “Mountain Building in 4 Dimensions” project, German branch of the European AlpArray initiative, which aims at better understanding the deep crustal-mantle structures of the Alpine Orogen and their relation to surface processes. Our results show a first phase of onset of foreland sedimentation in the eastern NAFB between c. 33-28 Ma, followed by a strong tectonic-driven subsidence between c. 28-25 Ma ending by a phase of erosion and the formation of a basin-wide Northern Slope Unconformity (NSU; Fig. 1C & 1D). During this time period, the rift-related Mesozoic normal faults of the European platform were reactivated and are capped by the NSU (Fig. 1D). We interpret this phase as an increase in the flexure of the subducting European Plate under the growing Alpine Orogen. Between 25-19 Ma, the eastern NAFB remained in a deep-marine, underfilled state with a gently increase in subsidence. A major shift took place around 19-17 Ma with strong tectonic-driven uplift, ranging from 200 m (absolute minimum) to 1200 m depending on uncertainties on paleo-water depths, and rapid sedimentary infill of the basin (Fig. 1C & 1D). We discuss the possible causes for this major tectono-sedimentary shift in the eastern NAFB in relation to contemporaneous changes in collisional tectonics within the Eastern and Southern Alps, and with a potential Early Miocene slab break-off event beneath the Eastern Alps

Graphene-doped photo-patternable ionogels: tuning of conductivity and mechanical stability of 3D microstructures

This work reports for the first time the development of enhanced conductivity, graphene- doped photo-patternable hybrid organic-inorganic ionogels and the effect of the subsequent materials condensation on the conductivity and mechanical stability of three- dimensional microstructures fabricated by multi-photon polymerisation (MPP). Ionogels were based on photocurable silicon/zirconium hybrid sol-gel materials and phosphonium (trihexyltetradecylphosphonium dicyanamide [P6,6,6,14][DCA] ionic liquid (IL). To optimise the dispersion of graphene within the ionogel matrices, aqueous solutions of graphene were prepared, as opposed to the conventional graphene powder approach, and employed as catalysts of hydrolysis and condensation reactions occurring in the sol-gel process. Ionogels were prepared via a two step process by varying the hydrolysis degree from 25 to 50%, IL content between 0-50 w/w%, and the inorganic modifier (zirconate complex) concentration from 30 to 60 mol.% against the photocurable ormosil and they were characterised via Raman, Electrochemical Impedance Spectroscopy and Transmission Electron Microscopy. MPP was performed on the hybrid ionogels, resulting in three- dimensional microstructures that were characterised using scanning electron microscopy. It is clearly demonstrated that the molecular formulation of the ionogels, including the concentration of graphene and the zirconate network modifier, play a critical role in the conductivity of the ionogels and influence the resulting mechanical stability of the fabricated three-dimensional microstructures. This work aims to establish for the first time the relationship between the molecular design and condensation of materials in the physico-chemistry and dynamic of ionogels

Increasing Glucose 6-Phosphate Dehydrogenase Activity Restores Redox Balance in Vascular Endothelial Cells Exposed to High Glucose

Previous studies have shown that high glucose increases reactive oxygen species (ROS) in endothelial cells that contributes to vascular dysfunction and atherosclerosis. Accumulation of ROS is due to dysregulated redox balance between ROS-producing systems and antioxidant systems. Previous research from our laboratory has shown that high glucose decreases the principal cellular reductant, NADPH by impairing the activity of glucose 6-phosphate dehydrogenase (G6PD). We and others also have shown that the high glucose-induced decrease in G6PD activity is mediated, at least in part, by cAMP-dependent protein kinase A (PKA). As both the major antioxidant enzymes and NADPH oxidase, a major source of ROS, use NADPH as substrate, we explored whether G6PD activity was a critical mediator of redox balance. We found that overexpression of G6PD by pAD-G6PD infection restored redox balance. Moreover inhibition of PKA decreased ROS accumulation and increased redox enzymes, while not altering the protein expression level of redox enzymes. Interestingly, high glucose stimulated an increase in NADPH oxidase (NOX) and colocalization of G6PD with NOX, which was inhibited by the PKA inhibitor. Lastly, inhibition of PKA ameliorated high glucose mediated increase in cell death and inhibition of cell growth. These studies illustrate that increasing G6PD activity restores redox balance in endothelial cells exposed to high glucose, which is a potentially important therapeutic target to protect ECs from the deleterious effects of high glucose