bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensitivity of WRF cloud microphysics to simulations of a severe thunderstorm event over Southeast India
Authors: Rajeevan M. , Kesarkar A. , Thampi S. B. , Rao T. N. , Radhakrishna B. , Rajasekhar M.
Published: June 2010

Abstract. In the present study, we have used the Weather Research and Forecasting (WRF) model to simulate the features associated with a severe thunderstorm observed over Gadanki (13.5° N, 79.2° E), over southeast India, on 21 May 2008 and examined its sensitivity to four different microphysical (MP) schemes (Thompson, Lin, WSM6 and Morrison). We have used the WRF model with three nested domains with the innermost domain of 2 km grid spacing with explicit convection. The model was integrated for 36 h with the GFS initial conditions of 00:00 UTC, 21 May 2008. For validating simulated features of the thunderstorm, we have considered the vertical wind measurements made by the Indian MST radar installed at Gadanki, reflectivity profiles by the Doppler Weather Radar at Chennai, and automatic weather station data at Gadanki. There are major differences in the simulations of the thunderstorm among the MP schemes, in spite of using the same initial and boundary conditions and model configuration. First of all, all the four schemes simulated severe convection over Gadanki almost an hour before the observed storm. The DWR data suggested passage of two convective cores over Gadanki on 21 May, which was simulated by the model in all the four MP schemes. Comparatively, the Thompson scheme simulated the observed features of the updraft/downdraft cores reasonably well. However, all the four schemes underestimated strength and vertical extend of the updraft cores. The MP schemes also showed problems in simulating the downdrafts associated with the storm. While the Thompson scheme simulated surface rainfall distribution closer to observations, the other three schemes overestimated observed rainfall. However, all the four MP schemes simulated the surface wind variations associated with the thunderstorm reasonably well. The model simulated reflectivity profiles were consistent with the observed reflectivity profile, showing two convective cores. These features are consistent with the simulated condensate profiles, which peaked around 5–6 km. As the results are dependent on initial conditions, in simulations with different initial conditions, different schemes may become closer to observations. The present study suggests not only large sensitivity but also variability of the microphysical schemes in the simulations of the thunderstorm. The study also emphasizes the need for a comprehensive observational campaign using multi-observational platforms to improve the parameterization of the cloud microphysics and land surface processes over the Indian region.
Atmospheric composition forecasting in Europe
Authors: Menut L. , Bessagnet B.
Published: June 2010

Abstract. The atmospheric composition is a societal issue and, following new European directives, its forecast is now recommended to quantify the air quality. It concerns both gaseous and particles species, identified as potential problems for health. In Europe, numerical systems providing daily air quality forecasts are numerous and, mostly, operated by universities. Following recent European research projects (GEMS, PROMOTE), an organization of the air quality forecast is currently under development. But for the moment, many platforms exist, each of them with strengths and weaknesses. This overview paper presents all existing systems in Europe and try to identify the main remaining gaps in the air quality forecast knowledge. As modeling systems are now able to reasonably forecast gaseous species, and in a lesser extent aerosols, the future directions would concern the use of these systems with ensemble approaches and satellite data assimilation. If numerous improvements were recently done on emissions and chemistry knowledge, improvements are still needed especially concerning meteorology, which remains a weak point of forecast systems. Future directions will also concern the use of these forecast tools to better understand and quantify the air pollution impact on health.
Auroral and sub-auroral phenomena: an electrostatic picture
Authors: De Keyser J. , Echim M.
Published: June 2010

Abstract. Many auroral and sub-auroral phenomena are manifestations of an underlying magnetosphere-ionosphere coupling. In the electrostatic perspective the associated auroral current circuit describes how the generator (often in the magnetosphere) is connected to the load (often in the ionosphere) through field-aligned currents. The present paper examines the generic properties of the current continuity equation that characterizes the auroral circuit. The physical role of the various elements of the current circuit is illustrated by considering a number of magnetospheric configurations, various auroral current-voltage relations, and different types of behaviour of the ionospheric conductivity. Based on realistic assumptions concerning the current-voltage relation and the ionospheric conductivity, a comprehensive picture of auroral and sub-auroral phenomena is presented, including diffuse aurora, discrete auroral arcs, black aurora, and subauroral ion drift. The electrostatic picture of field-aligned potential differences, field-aligned currents, ionospheric electric fields and plasma drift, and spatial scales for all these phenomena is in qualitative agreement with observations.
Observational features of equatorial coronal hole jets
Authors: Nisticò G. , Bothmer V. , Patsourakos S. , Zimbardo G.
Published: June 2010

Abstract. Collimated ejections of plasma called "coronal hole jets" are commonly observed in polar coronal holes. However, such coronal jets are not only a specific features of polar coronal holes but they can also be found in coronal holes appearing at lower heliographic latitudes. In this paper we present some observations of "equatorial coronal hole jets" made up with data provided by the STEREO/SECCHI instruments during a period comprising March 2007 and December 2007. The jet events are selected by requiring at least some visibility in both COR1 and EUVI instruments. We report 15 jet events, and we discuss their main features. For one event, the uplift velocity has been determined as about 200 km s−1, while the deceleration rate appears to be about 0.11 km s−2, less than solar gravity. The average jet visibility time is about 30 min, consistent with jet observed in polar regions. On the basis of the present dataset, we provisionally conclude that there are not substantial physical differences between polar and equatorial coronal hole jets.
Field-aligned current associated with low-latitude plasma blobs as observed by the CHAMP satellite
Authors: Park J. , Lühr H. , Stolle C. , Rother M. , Min K. W. , Michaelis I.
Published: June 2010

Abstract. Here we give two examples of low-latitude plasma blobs accompanied by linearly polarized perpendicular magnetic deflections which imply that associated field-aligned currents (FACs) have a 2-D sheet structure located at the blob walls. The estimated FAC density is of the order of 0.1 μA/m2. The direction of magnetic deflections points westward of the magnetic meridian and there is a linear correlation between perpendicular and parallel variations. All these properties are similar to those of equatorial plasma bubbles (EPBs). According to CHAMP observations from August 2000 to July 2004, blobs show except for these two good examples no clear signatures of 2-D FAC sheets at the walls. Generally, perpendicular magnetic deflections inside blobs are weaker than inside EPBs on average. Our results are consistent with existing theories: if a blob exists, (1) a significant part of EPB FAC will be closed through it, exhibiting similar perpendicular magnetic deflection inside EPBs and blobs, (2) the FAC closure through blobs leads to smaller perpendicular magnetic deflection at its poleward/downward side, and (3) superposition of different FAC elements might result in a complex magnetic signature around blobs.
Observations of the auroral width spectrum at kilometre-scale size
Authors: Partamies N. , Syrjäsuo M. , Donovan E. , Connors M. , Charrois D. , Knudsen D. , Kryzanowsky Z.
Published: June 2010

Abstract. This study examines auroral colour camera data from the Canadian Dense Array Imaging SYstem (DAISY). The Dense Array consists of three imagers with different narrow (compared to all-sky view) field-of-view optics. The main scientific motivation arises from an earlier study by Knudsen et al. (2001) who used All-Sky Imager (ASI) combined with even earlier TV camera observations (Maggs and Davis, 1968) to suggest that there is a gap in the distribution of auroral arc widths at around 1 km. With DAISY observations we are able to show that the gap is an instrument artifact and due to limited spatial resolution and coverage of commonly used instrumentation, namely ASIs and TV cameras. If the auroral scale size spectrum is indeed continuous, the mechanisms forming these structures should be able to produce all of the different scale sizes. So far, such a single process has not been proposed in the literature and very few models are designed to interact with each other even though the range of their favourable conditions do overlap. All scale-sizes should be considered in the future studies of auroral forms and electron acceleration regions, both in observational and theoretical approaches.
The Empirical Forcing Function as a tool for the diagnosis of large-scale atmospheric anomalies
Authors: Andrade C. , Santos J. A. , Pinto J. G. , Corte-Real J. , Leite S.
Published: June 2010

Abstract. The time-mean quasi-geostrophic potential vorticity equation of the atmospheric flow on isobaric surfaces can explicitly include an atmospheric (internal) forcing term of the stationary-eddy flow. In fact, neglecting some non-linear terms in this equation, this forcing can be mathematically expressed as a single function, called Empirical Forcing Function (EFF), which is equal to the material derivative of the time-mean potential vorticity. Furthermore, the EFF can be decomposed as a sum of seven components, each one representing a forcing mechanism of different nature. These mechanisms include diabatic components associated with the radiative forcing, latent heat release and frictional dissipation, and components related to transient eddy transports of heat and momentum. All these factors quantify the role of the transient eddies in forcing the atmospheric circulation. In order to assess the relevance of the EFF in diagnosing large-scale anomalies in the atmospheric circulation, the relationship between the EFF and the occurrence of strong North Atlantic ridges over the Eastern North Atlantic is analyzed, which are often precursors of severe droughts over Western Iberia. For such events, the EFF pattern depicts a clear dipolar structure over the North Atlantic; cyclonic (anticyclonic) forcing of potential vorticity is found upstream (downstream) of the anomalously strong ridges. Results also show that the most significant components are related to the diabatic processes. Lastly, these results highlight the relevance of the EFF in diagnosing large-scale anomalies, also providing some insight into their interaction with different physical mechanisms.
Decrease of the electric field penetration into the ionosphere due to low conductivity at the near ground atmospheric layer
Authors: Ampferer M. , Denisenko V. V. , Hausleitner W. , Krauss S. , Stangl G. , Boudjada M. Y. , Biernat H. K.
Published: June 2010

Abstract. It is well known that lithospheric electromagnetic emissions are generated before earthquakes occurrence. In our study, we consider the physical penetration mechanism of the electric field from the Earth's surface, through the atmosphere-ionosphere layers, and until its detection in space by satellites. A simplified approach is investigated using the electric conductivity equation, i.e., ∇ˆσ·∇Φ)=0 in the case of a vertical inclination of the geomagnetic field lines. Particular interest is given to the conductivity profile near the ground and the electric field distribution at the Earth's surface. Our results are discussed and compared to the models of Pulinets et al. (2003) and Denisenko et al. (2008). It is shown that the near ground atmospheric layer with low conductivity decreases the electric field penetration into the ionosphere. The model calculations have demonstrated that the electric field of lithospheric origin is too weak to be observed at satellite altitudes.
Time delay and duration of ionospheric total electron content responses to geomagnetic disturbances
Authors: Liu J. , Zhao B. , Liu L.
Published: June 2010

Abstract. Although positive and negative signatures of ionospheric storms have been reported many times, global characteristics such as the time of occurrence, time delay and duration as well as their relations to the intensity of the ionospheric storms have not received enough attention. The 10 years of global ionosphere maps (GIMs) of total electron content (TEC) retrieved at Jet Propulsion Laboratory (JPL) were used to conduct a statistical study of the time delay of the ionospheric responses to geomagnetic disturbances. Our results show that the time delays between geomagnetic disturbances and TEC responses depend on season, magnetic local time and magnetic latitude. In the summer hemisphere at mid- and high latitudes, the negative storm effects can propagate to the low latitudes at post-midnight to the morning sector with a time delay of 4–7 h. As the earth rotates to the sunlight, negative phase retreats to higher latitudes and starts to extend to the lower latitude toward midnight sector. In the winter hemisphere during the daytime and after sunset at mid- and low latitudes, the negative phase appearance time is delayed from 1–10 h depending on the local time, latitude and storm intensity compared to the same area in the summer hemisphere. The quick response of positive phase can be observed at the auroral area in the night-side of the winter hemisphere. At the low latitudes during the dawn-noon sector, the ionospheric negative phase responses quickly with time delays of 5–7 h in both equinoctial and solsticial months. Our results also manifest that there is a positive correlation between the intensity of geomagnetic disturbances and the time duration of both the positive phase and negative phase. The durations of both negative phase and positive phase have clear latitudinal, seasonal and magnetic local time (MLT) dependence. In the winter hemisphere, long durations for the positive phase are 8–11 h and 12–14 h during the daytime at middle and high latitudes for 20≤Ap<40 and Ap≥40.
Waves in shallow water off west coast of India during the onset of summer monsoon
Authors: Sanil Kumar V. , Sajiv Philip C. , Balakrishnan Nair T. N.
Published: June 2010

Abstract. The wave growth characteristics during the onset of summer monsoon in a swell dominated open ocean at a location off the west coast of India at 14 m water depth are studied. 67% of the measured waves are due to the swells arriving from south and south-west and the balance was due to the seas from south-west to north-west. Wave age of the measured data indicates that the measured waves are young sea with presence of swells. Even when the wind speed reduced to less than 3 m/s, significant wave height more than 2 m is present due to the swells in the Arabian Sea. The maximum wave height increased from 2 to 8 m within 60 h. The mean wave directions at the high frequencies align with the westerly wind direction and gradually shift to south-westerly swell direction at low frequencies during the wave growth. The strong westerly winds present between longitude 72° and 72.5° at latitude 12.5° has created the high waves (Hm0 upto 5.65 m) during the measurement period.
Relative O- and X-mode transmitted power from SuperDARN as it relates to the RRI instrument on ePOP
Authors: Gillies R. G. , Hussey G. C. , Sofko G. J. , James H. G.
Published: June 2010

Abstract. The Cascade Demonstrator Small-Sat and Ionospheric Polar Explorer (CASSIOPE) satellite is scheduled to be launched in 2010. On board this satellite will be a suite of eight scientific instruments comprising the enhanced Polar Outflow Probe (ePOP). One instrument is the Radio Receiver Instrument (RRI) which will be used to receive HF transmissions from various ground transmitters such as the Super Dual Auroral Radar Network (SuperDARN) array. Magnetoionic polarization and propagation theory have been used to model the relative power that SuperDARN delivers to the Ordinary (O) and Extraordinary (X) modes of propagation. These calculations have been performed for various frequencies in the SuperDARN transmitting band and for all five Canadian based SuperDARN radars. The geometry of the radars with respect to the background magnetic field results in the X-mode dominating the transmitted signal when the modelled wave propagates northward and is nearly perpendicular to the magnetic field lines. Other propagation directions (i.e., above or southwards of the radar) results in propagation which is anti-parallel to the magnetic field lines and an equal splitting of transmitted power between the O- and X-modes occurs. The modelling analysis shows that for either high transmitting frequencies or low ionospheric electron densities, the range of latitudes that signal will be received is quite large (up to ~90° of latitude). Also for these conditions, the range of elevations where the X-mode signal strongly dominates the O-mode signal will be apparent in the received signal. Conversely, for lower transmitting frequencies or higher ionospheric electron densities, the latitudinal range that signal will be received over is smaller. Here the X-mode-only band is not apparent in the received signal as both modes will be received with roughly equal power. These relative mode power calculations can be used to characterize the average electron density content in the ionosphere or provide a measure of relative absorption in the D- and E-regions when the satellite passes through the field-of-view of a SuperDARN radar.
Ground-based observations of diffuse auroral structures in conjunction with Reimei measurements
Authors: Samara M. , Michell R. G. , Asamura K. , Hirahara M. , Hampton D. L. , Stenbaek-Nielsen H. C.
Published: June 2010

Abstract. We present results from ground-based auroral observations coordinated with the Japanese satellite, Reimei, that took place during the winters of 2006, 2007 and 2008 at Poker Flat, Alaska. Comparable temporal and spatial resolution for the optical and in situ particle data, allowed for investigation of small scale and/or rapidly time-varying auroral structures. Four satellite passes through diffuse auroral structures were identified. The structures within the aurora, whether stationary or time-varying (pulsating aurora), were most closely correlated with the highest energy precipitating electrons measured by these detectors (8 to 12 keV). This relation is found to be consistent across all four examples, revealing that the electron precipitation responsible for these diffuse auroral structures is primarily that of the ≥8 keV electrons.
Storming the Bastille: the effect of electric fields on the ionospheric F-layer
Authors: Rishbeth H. , Heelis R. A. , Makela J. J. , Basu S.
Published: June 2010

Abstract. We discuss different phenomena occurring during ionospheric F-region storms that in principle might be caused by electric fields and point out challenges that must be faced when considering the physical processes at work. We consider the transport of plasma across many degrees of latitude at sub-auroral latitudes, the origin of patches of so-called "storm enhanced density" at high mid-latitudes, and the very high reported heights of the F2 peak at low latitudes. We discuss the role that electric fields might play in changing locally the net production of ionization as well as transporting it. We suggest that the local change in ionization production should be considered as a more important process for producing plasma density enhancements than transport from a more remote source of enhanced density.
The relationship between subsurface hydrology and dissolved carbon fluxes for a sub-arctic catchment
Authors: Lyon S. W. , Mörth M. , Humborg C. , Giesler R. , Destouni G.
Published: June 2010

Abstract. In recent years, there has been increased interest in carbon cycling in natural systems due to its role in a changing climate. Northern latitude systems are especially important as they may serve as a potentially large source or sink of terrestrial carbon. There are, however, a limited number of investigations reporting on actual flux rates of carbon moving from the subsurface landscape to surface water systems in northern latitudes. In this study, we determined dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) fluxes from the subsurface landscape for a sub-arctic catchment located in northern Sweden. These are based on observed annual flux-averaged concentrations of DOC and DIC for the 566 km2 Abiskojokken catchment. We demonstrate the importance to correctly represent the spatial distribution of the advective solute travel times along the various flow and transport pathways. The fluxes of DOC and DIC from the subsurface landscape to the surface water system were comparable in magnitude. This balance could shift under future climatic changes that influence the hydrological and biogeochemical system.
Potassium: Radonuclides
Authors: Jun Taehong , Tsay Olga G. , Churchill David G.
Published: June 2010

There are currently 28 known nuclides of potassium (K). Three of these are naturally occurring:
39
K,
40
K, and
41
K of which potassium‐40 is the only naturally occurring radionuclide. With its long half‐life of 1.28 × 10
9
years and an abundance of 0.012%,
40
K is a discrete source of natural radiation. Thus, in potassium‐rich foods, minerals, etc., a distinct natural dose is unavoidable for humans and all living creatures on Earth. Thus, it may be quantified in soil, plants, and animals and allows for various studies. Potassium‐40 may decay to calcium‐40 (89% probability) or may undergo electron capture (EC) to give argon‐40 (11% probability). The
biological
half‐life (excretion time decay) of
40
K, however, is 30 days. As it is often found in many mineral forms, potassium‐40 is a common constituent of soil and water, but not air. There are various reports in which
40
K is tracked migrating from soil(s) into various plants. In countries such as Europe and Brazil, drinking water was also scrutinized and found to contain
abnormal
levels of
40
K. The abundance of
40
K in human diet and foods from places such as China, Pakistan, and Ukraine has also been studied.
Cesium: Radionuclide
Authors: Lima Enrique
Published: June 2010

Radionuclides of cesium are generated mainly from nuclear fission. Many cesium radionuclides are known, but
134
Cs and
137
Cs are of the greatest concern because of their radiological properties. Cesium is present in polluted effluents of nuclear power plants. Gas, liquid, and solid wastes contaminated with cesium can be found but aqueous effluents, where cesium is present in the cationic form, are the most common. These cations can reach agricultural fields due to their high affinity for clays. Thus, cesium radionuclides can be incorporated into the food chain, and ultimately transported to human beings.
Phosphorus: Radionuclides
Authors: Kim Kibong , Churchill David G.
Published: June 2010

32P and33P are important radionuclides of phosphorus with half‐lives of 14.3 and 25.3 days, respectively, and which decay via β−emission. These isotopes (of 23 known) have anthropogenic sources and are prepared by the enrichment of sulfur. The radionuclides are used in tracer studies primarily as phosphate, or other common phosphate forms such as “phosphate rock” or ortho‐phosphoric acid. Various labeling and therapeutic studies have been performed in the fields of biology, botany, and in clinical medicine and are mentioned herein. Radioisotopes of phosphorus can be detected by liquid scintillation counting. There is, however, limited knowledge about remediation as32P and33P are short‐lived.
Uranium: Radionuclides
Authors: Vandenhove Hildegarde , Hurtgen Christian , Payne Timothy E.
Published: June 2010

This article describes the occurrence, chemistry, and bioavailability of uranium (U) in terrestrial and aquatic environments, its analysis in environmental samples, and remedial measures applicable to uranium‐contaminated water and soil. Uranium is widely distributed throughout the world. There are three main isotopes present in natural uranium, which comprises234U (0.0055%),235U (0.72%), and238U (99.27%). Uranium can occur either in its reduced state (U(IV)), which is generally highly immobile, or in its more soluble and mobile (U(VI)) state. Uranium mobility and bioavailability are governed by oxidation state, complexation by organic and inorganic ligands, pH, sorption by minerals including clays and hydroxides, and interactions with organic matter. In uncontaminated surface waters uranium content is generally low (<1 ppb). Most groundwaters are low in uranium but the concentration range is large (<0.001–2600 ppb), resulting from the interaction of groundwater with naturally occurring uranium‐bearing materials or anthropogenic contamination sources. Since groundwater is a major source for drinking water, various methods have been developed to remove uranium from potable water. Similar methods are applied in wastewater treatment. Extraction and processing of uranium ore or minerals containing natural radionuclides has resulted in the generation of waste streams. The major challenge associated with these contaminated waste streams, residues, or sites is typically the larger volumes of material and the relatively low specific activities.
Mediterranean Sea: Radionuclides
Authors: Delfanti Roberta , Papucci Carlo
Published: June 2010

The main sources of anthropogenic radioactivity in the Mediterranean Sea are fallout from atmospheric nuclear weapon testing and from the Chernobyl accident in 1986, while the releases from the nuclear industry are small. Consequently, the present radionuclide levels in the marine environment are of no concern from the radiological point of view. However, the Mediterranean Sea is an ideal environment to show how both coastal and open‐sea processes act to redistribute radionuclides in the different compartments of the marine environment. In fact, the Mediterranean Sea is considered a miniature ocean, where all the processes characterizing the global ocean take place on smaller space and timescales. For these reasons, in the past decades it had largely been used as a “laboratory basin” for process studies. In this framework, anthropogenic and natural radionuclides were often measured to be used as tracers of water mass dynamics, transit and renewal times, particle dynamics, sediment accumulation, etc. In this article, we first briefly describe the physical and biogeochemical characteristics of the Mediterranean Sea. After reviewing and quantifying the sources of radioactivity, we mainly focus on two radionuclides: (i)137Cs: conservative in the open sea, the most abundant anthropogenic radionuclide, and, among these, the main contributor to radioactive dose to the population, and (ii) the very long‐lived239,240Pu: nonconservative and the most abundant among transuranics. We describe their distribution and time trend in seawater, sediments, and biota, define their budgets in the basin, quantify the exchanges at the Gibraltar and Turkish Straits, and indicate future trends. We also report levels and distributions of selected natural radionuclides: (i)238U, with234Th as the main tracer for particle dynamics and whose concentration in the Mediterranean slightly differs from that in the oceans, and (ii)210Po, which is efficiently accumulated by marine organisms and is the main contributor to radioactive dose to the population. Finally, we identify topics for future research, mainly related to the application of nuclear techniques to the study of oceanographic processes.
Cesium: Global Ocean Distribution
Authors: Inomata Yayoi
Published: June 2010

Since the 1950s Cesium‐137(137Cs) concentrations in the surface waters of the global ocean have been extensively measured in numerous studies. This article, based on the analysis of the137Cs concentrations in the HAM‐global database, summarizes the results of spatial and temporal variations in137Cs concentrations in the surface waters (0–10 m) of the global ocean for the period 1957 to 2005.137Cs in the surface waters of the North Pacific Ocean and North Atlantic Ocean has mainly originated from the nuclear weapon testing global fallout in the late 1950s and early 1960s. In the 1970s and 1980s, the discharge from the nuclear fuel reprocessing plants was the dominant source for the North Atlantic Ocean and its northeast marginal seas. The seas that were largely affected by the fallout of the Chernobyl accident in 1986 were the Baltic, the Black, and the Mediterranean Seas. In the 1990s and 2000s, the137Cs concentrations were decreasing in the global ocean. During this time, the difference in concentrations in the various seas reduced when compared with those in the 1960s and 1970s. In 2005, the most anthropogenic137Cs contaminated area of the global ocean was Baltic Sea, whereas the most undisturbed area was the Antarctic Ocean.137Cs in the surface water had an almost homogeneous distribution in the North Pacific, the equatorial region in the Pacific, and the Indian Ocean. The fact that the apparent‐half residence time (the decreasing rate of137Cs concentration) is almost equal in these regions suggests that the137Cs injected into the western North Pacific Ocean by global fallout was transported to the subtropics and tropics through oceanographic processes. Part of137Cs was recirculated in the Pacific Ocean, and the rest was transported into the Indian Ocean via the Indonesian through flow.
Perfluorinated Polymers, Polytetrafluoroethylene
Authors: Gangal Subhash V. , Brothers Paul D.
Published: June 2010

Polytetrafluoroethylene (PTFE) has a unique position in the plastics industry due to its chemical inertness, heat resistance, excellent electrical insulation properties, and low coefficient of friction over a wide temperature range. The white to translucent solid polymer has an extremely high molecular weight in the 106–107 range. PTFE is a highly crystalline polymer with high thermal stability derived from the strong carbon‐fluorine bond. As a result, PTFE is a very useful high temperature polymer. Commercial PTFE is manufactured by two different polymerization processes that result in two different types of chemically identical polymers. Suspension polymerization produces a granular resin and emulsion polymerization is used to produce fine powder resins (coagulated dispersion) or aqueous dispersions. Because of its high molecular weight, PTFE does not flow and can not be fabricated by conventional techniques. The suspension polymerized PTFE is usually fabricated by modified metallurgy techniques. Emulsion polymerized, coagulated PTFE is processed by a cold extrusion process while the stabilized aqueous dispersions are processed according to latex processing techniques.
Pulsed Power Applications with Conductive (Carbon‐Loaded) Composite Polymer Electrodes—Requirements and Characterization
Authors: Roodenburg Bart , de Haan Sjoerd , Malchev Plamen , Leitão Telma , Mendes Eduardo
Published: June 2010

Pulsed power (PP) is a technology where energy is released to a load in a short time. Every device using this technology needs electrodes to transfer the electric energy to the load. Recent developments in composite conductive polymers make them suitable as electrodes for new or existing PP applications, where normally metals were used. Composite polymers, consisting of conductive filler and a nonconductive matrix, can solve several specific problems in common and to be developed (PP) applications, due to their ability to conduct current or to store electrical charge, in combination with their elasticity. In general, polymer electrodes behave differently on pulsed stimuli compared to a static load and metal electrodes. An overview of many existing characterization methods and a newly developed technique suited for characterization of conductive polymers for PP applications in particular is described. For three different applications,artificial muscles, cell electroporation, andbiofouling prevention, the requirements for the polymer electrodes and specific application‐related issues are addressed with examples.
Microstructure Analysis of Acrylate‐Methacrylate Copolymers by
13
C Nuclear Magnetic Resonance Spectroscopy
Authors: Matlengiewicz Marek
Published: June 2010

Microstructure of acrylate‐methacrylate copolymers can be determined in detail by means of
13
C nuclear magnetic resonance (NMR) spectroscopy. Several signals in the
13
C NMR spectra of such copolymers are sensitive to compositional and conformational differences in the macromolecular chain. However, only the carbonyl and β‐CH
2
carbons from the main chain provide complete and complementary information on distribution of configurational–compositional sequences, since only these two carbons are present in all (meth)acrylate units. Carbonyl signal is the source of information on distribution of odd sequences, usually up to configurational–compositional pentads. Complementary information, on distribution of even sequences, can be derived from the signal of β‐CH
2
carbons of the main chain. Spectral simulation can verify the signal assignment to respective sequences and incremental calculations of the chemical shifts of individual sequences were found to be useful for both carbonyl and methylene signal.
On‐line parameter estimation for a class of time‐varying continuous systems with bounded disturbances
Authors: Chen Jie , Zhang Guozhu , Li Zhiping
Published: June 2010

In this paper, we proposed an on‐line parameter estimation algorithm for a class of time‐varying continuous systems with bounded disturbance. In this method, a novel polynomial approximator with a bounded regressor vector is constructed and utilized to approximate the time‐varying parameters. The direct least‐squares algorithm is employed to acquire the on‐line estimates, so that several useful properties of the direct estimation, such as fast convergence and robustness to the bounded disturbance, are reflected in our method. We have proved that the estimation error of this method is bounded. Furthermore, the bound on the Euclidean norm of the estimation error is derived. The simulation results demonstrate that this method can provide accurate estimates of time‐varying parameters even under the influence of bounded disturbance. Copyright © 2010 John Wiley & Sons, Ltd.
The Bipolar Association Case–Control Study (BACCS) and meta‐analysis: No association with the 5,10‐Methylenetetrahydrofolate reductase gene and bipolar disorder
Authors: Cohen‐Woods Sarah , Craig Ian , Gaysina Darya , Gray Joanna , Gunasinghe Cerisse , Craddock Nick , Elkin Amanda , Jones Lisa , Kennedy James , King Nicole , Korszun Ania , Knight Jo , Owen Michael , Parikh Sagar , Strauss John , Sterne Abram , Tozzi Federica , Perry Julia , Muglia Pierandrea , Vincent John , McGuffin Peter , Farmer Anne
Published: June 2010

Bipolar disorder (BD) is a complex genetic disease for which the underlying pathophysiology has yet to be fully explained. 5,10‐Methylenetetrahydrofolate reductase (MTHFR) is a crucial enzyme in folate‐mediated one‐carbon metabolism and folate deficiency can be associated with psychiatric symptoms. A single base variant in MTHFR gene (C677T) results in the production of a mildly dysfunctional thermolabile enzyme and has recently been implicated in BD. We conducted an association study of this polymorphism in 897 patients with bipolar I or bipolar II disorder, and 1,687 healthy control subjects. We found no evidence for genotypic or allelic association in this sample. We also performed a meta‐analysis of our own, and all published data, and report no evidence for association. Our findings suggest that the MTHFR C677T polymorphism is not involved in the genetic etiology of clinically significant BD. © 2010 Wiley‐Liss, Inc.
Identification of a novel genetic locus on chromosome 8p21.1–q11.23 for idiopathic basal ganglia calcification
Authors: Dai Xiaohua , Gao Yong , Xu Zhenping , Cui Xiaoniu , Liu Juan , Li Yulei , Xu Haibo , Liu Mugen , Wang Qing K. , Liu Jing Yu
Published: June 2010

Idiopathic basal ganglia calcification (IBGC) is a neurodegenerative disorder that is characterized by basal ganglia and extrabasal ganglia calcification, and usually inherited in an autosomal dominant pattern. To date, two genetic loci for IBGC were identified on chromosomes 14q and 2q, but further genetic heterogeneity clearly exists. In this study, a large Chinese family with autosomal dominant IBGC was characterized. Linkage analysis excluded the 14q13 and 2q37 loci. The large family was then characterized by genome‐wide linkage analysis to identify a novel genetic locus for IBGC. Significant linkage was identified with markers on chromosome 8p21.1–q11.23 with a maximum LOD score of 4.10. Fine mapping defined the new genetic locus within a 25 Mb region between markers D8S1809 and D8S1833. Future studies of the candidate genes at the 8p21.1–q11.23 locus may lead to identification of a disease‐causing gene with IBGC. © 2010 Wiley‐Liss, Inc.
Positive symptoms of psychosis correlate with expression of ubiquitin proteasome genes in peripheral blood
Authors: Bousman Chad A. , Chana Gursharan , Glatt Stephen J. , Chandler Sharon D. , May Todd , Lohr James , Kremen William S. , Tsuang Ming T. , Everall Ian P.
Published: June 2010

Several brain‐ and blood‐based gene expression studies in patients with psychotic disorders (e.g., schizophrenia) have identified genes in the ubiquitin proteasome system (UPS) pathway as putative biomarkers. However, to date an examination of the UPS pathway in the broader context of symptom severity in psychosis has not been conducted. The purpose of this study was to investigate the correlation between clinical scores on the Scales for the Assessment of Positive and Negative Symptoms (SAPS–SANS) and expression of 43 highly annotated genes within the UPS pathway in blood from patients with psychosis. A sample of 19 psychotic patients diagnosed with schizophrenia (n = 13) or bipolar disorder (n = 6) were recruited. Pearson's partial correlations, adjusting for gender, ethnicity, age, education, medication, smoking, and past 6‐month substance use, were performed between each of the selected UPS genes and both scales. Significant Bonferroni‐adjusted positive associations were observed between SAPS scores and two ubiquitin conjugation genes (i.e., UBE2K, SIAH2), while a negative association was observed with one deubiquitination gene (i.e., USP2). No gene expression levels were significantly associated with scores on the SANS after correction for multiple testing. Our findings suggest that dysregulation of the UPS, specifically ubiquitin conjugation and deubiquitination, may point to a possible underlying biological mechanism for severity of positive but not negative symptoms. © 2010 Wiley‐Liss, Inc.
Association of a KCNA5 gene polymorphism with systemic sclerosis–associated pulmonary arterial hypertension in the European Caucasian population
Authors: Wipff J. , Dieudé P. , Guedj M. , Ruiz B. , Riemekasten G. , Cracowski J. L. , Matucci‐Cerinic M. , Melchers I. , Humbert M. , Hachulla E. , Airo P. , Diot E. , Hunzelmann N. , Caramaschi P. , Sibilia J. , Valentini G. , Tiev K. , Girerd B. , Mouthon L. , Riccieri V. , Carpentier P. H. , Distler J. , Amoura Z. , Tarner I. , Degano B. , Avouac J. , Meyer O. , Kahan A. , Boileau C. , Allanore Y.
Published: June 2010

Objective

Pulmonary arterial hypertension (PAH) has emerged as a leading cause of death in systemic sclerosis (SSc). The genetic basis of PAH has been unraveled in recent years, with a major role played by transforming growth factor β receptors; however, some other candidate genes have also been advocated, including potassium voltage‐gated channel, shaker‐related subfamily, member 5 (KCNA5). We undertook this study to determine whether KCNA5 polymorphisms confer susceptibility to SSc and its vascular phenotype, including PAH.

Methods

Four KCNA5 single‐nucleotide polymorphisms (SNPs), rs10744676, rs1860420, rs3741930, and rs2284136, were genotyped in a discovery set of 638 SSc patients and 469 controls. In addition, rs10744676 was genotyped in an independent replication sample (938 SSc patients and 564 controls) and in a cohort of 168 patients with different PAH subtypes.

Results

The KCNA5 rs10744676 variant was found to be associated with SSc in the discovery sample, with an odds ratio (OR) of 0.62 (95% confidence interval [95% CI] 0.48–0.79, adjusted P = 0.0003) in comparison with controls (C allele frequency 11.4% versus 17.2%). When subphenotypes were investigated, an association was found solely for PAH associated with SSc (OR 0.31 [95% CI 0.13–0.71], adjusted P = 0.04). The other KCNA5 SNPs tested were not associated with any SSc subset. The above association with PAH associated with SSc was replicated in the second set. In the combined population, rs10744676 was strongly associated with PAH associated with SSc in comparison with controls (OR 0.36 [95% CI 0.21–0.63], P = 0.0002). In the independent cohort of patients with PAH, after investigating PAH subtypes, only rs10744676 showed an association with PAH associated with SSc.

Conclusion

Our results provide the first evidence for an association between the KCNA5 rs10744676 variant and PAH associated with SSc.
The Fms‐like tyrosine kinase 3 ligand, a mediator of B cell survival, is also a marker of lymphoma in primary Sjögren's syndrome
Authors: Tobón Gabriel J. , Renaudineau Yves , Hillion Sophie , Cornec Divi , Devauchelle‐Pensec Valérie , Youinou Pierre , Pers Jacques‐Olivier
Published: June 2010

Objective

To determine if the Fms‐like tyrosine kinase 3 ligand (Flt‐3L), a cytokine implicated in B cell ontogenesis and proliferation in hematologic malignancies, might be responsible for the increased numbers of circulating Bm2 and Bm2′ B cell subsets in patients with primary Sjögren's syndrome (SS).

Methods

Serum levels of Flt‐3L were measured in 64 patients with primary SS and in 20 healthy controls matched for age and sex. Flt‐3L and its receptor Flt‐3 were quantified in circulating B cells and in salivary gland (SG) biopsy tissues by immunofluorescence analysis. The effect of Flt‐3L on circulating B lymphocytes was then determined by coculture with cells of a human SG (HSG) epithelial cell line.

Results

Serum levels of Flt‐3L were increased in patients with primary SS as compared with controls (mean ± SD 135.8 ± 5.5 versus 64.4 ± 4.5 pg/ml; P < 0.001). Serum levels of Flt‐3L in primary SS patients correlated with the numbers of Bm2 and Bm2′ cells (r = 0.46, P < 0.0006), and Flt‐3 was selectively expressed in Bm2 and Bm2′ cells. B cell culture experiments showed that Flt‐3L potentiated the proliferative effect of anti‐IgM stimulation. In SGs, we found that infiltrating B cells expressed Flt‐3 and epithelial cells produced Flt‐3L. Finally, Flt‐3L levels were associated with high disease activity scores and increased risk of developing lymphoma.

Conclusion

Serum levels of Flt‐3L are elevated in patients with primary SS and correlate with abnormal B cell distribution. Flt‐3 is mainly expressed by Bm2 and Bm2′ cells. Serum levels of Flt‐3L might explain the clinical evolution of primary SS to B cell lymphoma that is observed in some patients, thus opening the possibility of new avenues for therapy.
Effect of absorption site on the pharmacokinetics of sublingual asenapine in healthy male subjects
Authors: Gerrits Mireille , de Greef Rik , Peeters Pierre
Published: June 2010

Asenapine is a psychopharmacologic agent approved in the United States for the acute treatment of schizophrenia in adults and the acute treatment of manic or mixed episodes associated with bipolar I disorder with or without psychotic features in adults. It is pending approval for the treatment of schizophrenia and manic episodes associated with bipolar I disorder in Europe. Asenapine is administered as a sublingual formulation. To determine whether the pharmacokinetics of asenapine are impacted by placing the tablet buccally (‘cheeking’) or allowing the tablet to dissolve on the top of the tongue, pharmacokinetics were compared following buccal and supralingual administration versus sublingual administration. In this open‐label, randomized, 3‐way crossover trial, healthy men (n=36) received single 5 mg doses of asenapine via sublingual, supralingual and buccal routes, at least 1 week apart. With buccal administration, the area under the concentration‐over‐time curve (AUC0–∞) and peak concentration (Cmax) were, respectively, 24%, and 19% higher than with sublingual administration; these routes were not bioequivalent. With supralingual administration, AUC0–∞ and Cmax were 6% and 13% lower than with sublingual administration; bioequivalence was established based on AUC0–∞ only; bioequivalence based on Cmax could not be assessed due to 40% within‐subject variability. The most common adverse events were oral paresthesia (sublingual, 75.8%; supralingual, 55.9%; buccal, 45.7%) and somnolence (81.8%; 76.5%; 68.6%). Compared with the recommended sublingual route of asenapine administration, exposure was 24% higher with buccal administration and comparable to supralingual administration. However, differences in exposure associated with variable placement in the oral cavity did not compromise safety in healthy subjects. Copyright © 2010 John Wiley & Sons, Ltd.
Effect of varying feedstock–pretreatment chemistry combinations on the formation and accumulation of potentially inhibitory degradation products in biomass hydrolysates
Authors: Du Bowen , Sharma Lekh N. , Becker Christopher , Chen Shou‐Feng , Mowery Richard A. , van Walsum G. Peter , Chambliss C. Kevin
Published: June 2010

A variety of potentially inhibitory degradation products are produced during pretreatment of lignocellulosic biomass. Qualitative and quantitative interrogation of pretreatment hydrolysates is paramount to identifying potential correlations between pretreatment chemistries and microbial inhibition in downstream bioconversion processes. In the present study, corn stover, poplar, and pine feedstocks were pretreated under eight different chemical conditions, which are representative of leading pretreatment processes. Pretreatment processes included: 0.7% H2SO4, 0.07% H2SO4, liquid hot water, neutral buffer solution, aqueous ammonia, lime, lime with oxygen pressurization, and wet oxidation. Forty lignocellulosic degradation products resulting from pretreatment were analyzed using high performance liquid chromatography in combination with UV spectroscopy or tandem mass spectrometry detection (HPLC‐PDA‐MS/MS) and ion chromatography (IC). Of these compounds, several have been reported to be inhibitory, including furfural, hydroxymethyl furfural, ferulic acid, 3,4‐dihydroxybenzaldehyde, syringic acid among others. Formation and accumulation of monitored compounds in hydrolysates is demonstrated to be a function of both the feedstock and pretreatment conditions utilized. Biotechnol. Bioeng. 2010;107: 430–440. © 2010 Wiley Periodicals, Inc.