Despite the extensive use of 10Be as the most significant information source on past solar activity, there has been only one record (Dye‐3, Greenland) providing annual resolution over several ...centuries. Here we report a new annual resolution 10Be record spanning the period 1389–1994 AD, measured in an ice core from the NGRIP site in Greenland. NGRIP and Dye‐3 10Be exhibits similar long‐term variability, although occasional short term differences between the two sites indicate that at least two high resolution 10Be records are needed to assess local variations and to confidently reconstruct past solar activity. A comparison with sunspot and neutron records confirms that ice core 10Be reflects solar Schwabe cycle variations, and continued 10Be variability suggests cyclic solar activity throughout the Maunder and Spörer grand solar activity minima. Recent 10Be values are low; however, they do not indicate unusually high recent solar activity compared to the last 600 years.
Organic Bioelectronics Berggren, M.; Richter-Dahlfors, A.
Advanced materials (Weinheim),
10/2007, Letnik:
19, Številka:
20
Journal Article
Recenzirano
During the last two decades, organic electroactive materials have been explored as the working material in a vast array of electronic devices, promising low‐cost, flexible, and easily manufactured ...systems. The same materials also possess features that make them unique in bioelectronics applications, where electronic signals are translated into biosignals and vice versa. Here we review, in the broadest sense, the field of organic bioelectronics, describing the electronic properties and mechanisms of the organic electronic materials that are utilized in specific biological experiments.
Bioelectronics is a technology platform that enables signal transduction between biology and traditional electronics. This technology becomes successful only if electronic signals can be translated into biological equivalences, and vice versa, at proper temporal and spatial resolution. In addition, bioelectronic devices must exhibit proper biocompatibility and biostability to function properly over time. Organic electronic devices enable several advantages as compared to inorganic electronics, in many respects, and recent progress in organic bioelectronics is described in this Review.
Graft failure may contribute to increased morbidity and mortality after allogeneic hematopoietic SCT (allo-HSCT). Here, we present risk factors for graft failure in all first allo-HSCTs performed at ...our center from 1995 to mid-2010 (n=967). Graft failure was defined as >95% recipient cells any time after engraftment with no signs of relapse, or re-transplantation because of primary or secondary neutropenia (<0.5 × 10(9)/L) and/or thrombocytopenia (<30 × 10(9)/L). Fifty-four patients (5.6%) experienced graft failure. The majority were because of autologous reconstitution (n=43), and only a few patients underwent re-transplantation because of primary (n=6) or secondary (n=5) graft failures. In non-malignant disorders, graft failure had no effect on survival, whereas in malignant disease graft failure was associated with reduced 5-year survival (22 vs 53%, P<0.01). In multivariate analysis, ex vivo T-cell depletion (relative risk (RR) 8.82, P<0.001), HLA-mismatched grafts (RR 7.64, P<0.001), non-malignant disorders (RR 3.32, P<0.01) and reduced-intensity conditioning (RR 2.58, P<0.01) increased the risk for graft failure, whereas graft failures were prevented by total nucleated cell doses of ≥ 2.5 × 10(8)/kg (RR 0.36, P<0.01). In conclusion, graft failure was only associated with inferior survival in malignant disease. Non-malignant disorders, HLA match, conditioning intensity, immunosuppression regimen and cell dose all influenced graft failure risk.
All‐organic active matrix addressed displays based on electrochemical smart pixels made on flexible substrates are reported. Each individual smart pixel device combines an electrochemical transistor ...with an electrochromic display cell, thus resulting in a low‐voltage operating and robust display technology. Poly(3,4‐ethylenedioxythiophene) (PEDOT) doped with poly(styrenesulfonate) (PSS) served as the active material in the electrochemical smart pixels, as well as the conducting lines, of the monolithically integrated active‐matrix display. Different active‐matrix display addressing schemes have been investigated and a matrix display fill factor of 65 % was reached. This is achieved by combining a three‐terminal electrochemical transistor with an electrochromic display cell architecture, in which an additional layer of PEDOT:PSS was placed on top of the display cell counter electrode. In addition, we have evaluated different kinds of electrochromic polymer materials aiming at reaching a high color switch contrast. This work has been carried out in the light of achieving a robust display technology that is easily manufactured using a standard label printing press, which forced us to use the fewest different materials as well as avoiding exotic and complex device architectures. Together, this yields a manufacturing process of only five discrete patterning steps, which in turn promise for that the active matrix addressed displays can be manufactured on paper or plastic substrates in a roll‐to‐roll production procedure.
A holistic approach to improve fill factor, color contrast, and updating procedures of all‐organic electrochromic active‐matrix displays is reported. Further, the simplified electrochemical smart pixel design yields a robust technology that paves the way for roll‐to‐roll manufacturing of low‐voltage operating flexible displays utilizing standard printing techniques.
Dissolved organic matter (DOM) is a master variable in aquatic systems. Modern fluorescence techniques couple measurements of excitation emission matrix (EEM) spectra and parallel factor analysis ...(PARAFAC) to determine fluorescent DOM (FDOM) components and DOM quality. However, the molecular signatures associated with PARAFAC components are poorly defined. In the current study we characterized river water samples from boreal Québec, Canada, using EEM/PARAFAC analysis and ultrahigh resolution mass spectrometry (FTICR-MS). Spearman's correlation of FTICR-MS peak and PARAFAC component relative intensities determined the molecular families associated with 6 PARAFAC components. Molecular families associated with PARAFAC components numbered from 39 to 572 FTICR-MS derived elemental formulas. Detailed molecular properties for each of the classical humic- and protein-like FDOM components are presented. FTICR-MS formulas assigned to PARAFAC components represented 39% of the total number of formulas identified and 59% of total FTICR-MS peak intensities, and included significant numbers compounds that are highly unlikely to fluoresce. Thus, fluorescence measurements offer insight into the biogeochemical cycling of a large proportion of the DOM pool, including a broad suite of unseen molecules that apparently follow the same gradients as FDOM in the environment.
Organic materials can offer a low-cost alternative for printed electronics and flexible displays. However, research in these systems must exploit the differences - via molecular-level control of ...functionality - compared with inorganic electronics if they are to become commercially viable.
Reconstructing solar activity variability beyond the time scale of actual measurements provides invaluable data for modeling of past and future climate change. The 10Be isotope has been a primary ...proxy archive of past solar activity and cosmic ray intensity, particularly for the last millennium. There is, however, a lack of direct high‐resolution atmospheric time series on 10Be that enable estimating atmospheric modulation on the production signal. Here we report quasi‐weekly data on 10Be and 7Be isotopes covering the periods 1983–2000 and 1975–2006 respectively, that show, for the first time, coherent variations reflecting both atmospheric and production effects. Our data indicate intrusion of stratosphere/upper troposphere air masses that can modulate the isotopes production signal, and may induce relative peaks in the natural 10Be archives (i.e., ice and sediment). The atmospheric impact on the Be‐isotopes can disturb the production signals and consequently the estimate of past solar activity magnitude.
Recent published results in inverse scattering generally show the difficulty in dealing with moderate to high contrast inhomogeneities when employing linearized or iteratively linearized algorithms ...(e.g., distorted Born iterative method). This paper presents a fully nonlinear algorithm utilizing full wave field data, that results in ultrasound computed tomographic images from a laboratory breast scanner, and shows several such unique images from volunteer subjects. The forward problem, data collection process and inverse scattering algorithm used are discussed. A functional that represents the "best fit" between predicted and measured data is minimized, and therefore requires a very fast forward problem solver, Jacobian calculation, and gradient estimation, all of which are described. The data collection device is described. The algorithm and device yield quantitative estimates of human breast tissue in vivo. Several high resolution images, measuring ∼150 by 150 wavelengths, obtained from the 2D inverse scattering algorithms, using data collected from a first prototype, are shown and discussed. The quantitative values are compared with previous published work.
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