442 research outputs found
Polymers for spacecraft hardware materials specifications and engineering information Monthly technical progress report no. 19, Dec. 10, 1965 - Jan. 9, 1966
Thermal vacuum weight loss determinations of polymers for spacecraft construction material application
Polymers for spacecraft hardware materials specifications and engineering information Monthly technical progress report no. 18, Nov. 10 - Dec. 9, 1965
Chemical test procedures for analyzing potting compound bases for spacecraft construction material
Universal Behavior of the Coefficients of the Continuous Equation in Competitive Growth Models
The competitive growth models involving only one kind of particles (CGM), are
a mixture of two processes one with probability and the other with
probability . The dependance produce crossovers between two different
regimes. We demonstrate that the coefficients of the continuous equation,
describing their universality classes, are quadratic in (or ). We show
that the origin of such dependance is the existence of two different average
time rates. Thus, the quadratic dependance is an universal behavior of all
the CGM. We derive analytically the continuous equations for two CGM, in 1+1
dimensions, from the microscopic rules using a regularization procedure. We
propose generalized scalings that reproduce the scaling behavior in each
regime. In order to verify the analytic results and the scalings, we perform
numerical integrations of the derived analytical equations. The results are in
excellent agreement with those of the microscopic CGM presented here and with
the proposed scalings.Comment: 9 pages, 3 figure
The future of stem cells in liver diseases.
Preliminary experience with clinical hepatocyte transplantation during the past decade has provided proof of concept that cell therapy can be effective for the treatment of some liver diseases. Recent progress in cell biology resulting in the isolation and characterization of hepatic stem cells and progenitor cells further increased the expectation for a new approach to the treatment of genetic and chronic liver disease. Several potential sources have been identified of hepatic stem/ progenitor cells exhibiting both differentiation towards the hepatic lineage in vitro and hepatic parenchymal repopulation with liver-specific metabolic activity in liver-injured animal models. However, a few of these results proved to be poorly reproducible in different laboratories, and it was recognized that some initial optimistic conclusions were drawn from incorrect interpretation of experimental data or from insufficient knowledge of the mechanisms involved in tissue regeneration. Moreover, only modest results have emerged so far from ongoing clinical experience involving the use of putative stem cells in liver disease. There is much need for a joined effort to concentrate the resources on a specific cell population, in order to better characterize its function, to assess its safety and Concise Revie
Proteomics boosts translational and clinical microbiology
The application of proteomics to translational and clinical microbiology is one of the most advanced frontiers in the management and control of infectious diseases and in the understanding of complex microbial systems within human fluids and districts. This new approach aims at providing, by dedicated bioinformatic pipelines, a thorough description of pathogen proteomes and their interactions within the context of human host ecosystems, revolutionizing the vision of infectious diseases in biomedicine and approaching new viewpoints in both diagnostic and clinical management of the patient.Indeed, in the last few years, many laboratories have matured a series of advanced proteomic applications, aiming at providing individual proteome charts of pathogens, with respect to their morph and/or cell life stages, antimicrobial or antimycotic resistance profiling, epidemiological dispersion. Herein, we aim at reviewing the current state-of-the-art on proteomic protocols designed and set-up for translational and diagnostic microbiological purposes, from axenic pathogens' characterization to microbiota ecosystems' full description. The final goal is to describe applications of the most common MALDI-TOF MS platforms to advanced diagnostic issues related to emerging infections, increasing of fastidious bacteria, and generation of patient-tailored phylotypes. This article is part of a Special Issue entitled: Trends in Microbial Proteomics. © 2013 The Authors
Ultrafast extreme ultraviolet photoemission without space charge
Time- and Angle-resolved photoelectron spectroscopy from surfaces can be used
to record the dynamics of electrons and holes in condensed matter on ultrafast
time scales. However, ultrafast photoemission experiments using
extreme-ultraviolet (XUV) light have previously been limited by either
space-charge effects, low photon flux, or limited tuning range. In this
article, we describe space-charge-free XUV photoelectron spectroscopy
experiments with up to 5 nA of average sample current using a tunable
cavity-enhanced high-harmonic source operating at 88 MHz repetition rate. The
source delivers photons/s in isolated harmonics to the sample over
a broad photon energy range from 18 to 37 eV with a spot size of m. From photoelectron spectroscopy data, we place conservative upper
limits on the XUV pulse duration and photon energy bandwidth of 93 fs and 65
meV, respectively. The high photocurrent, lack of space charge distortions of
the photoelectron spectra, and excellent isolation of individual harmonic
orders allow us to observe the laser-assisted photoelectric effect with
sideband amplitudes as low as , enabling time-resolved XUV
photoemission experiments in a qualitatively new regime
Long-Term Prognostic Impact of Right Ventricular Dysfunction in Patients with COVID-19
The characteristics and clinical course of hospitalized patients with coronavirus disease 2019 (COVID-19) have been widely described, while long-term data are still poor. The aim of this study was to evaluate the long-term clinical outcome and its association with right ventricular (RV) dysfunction in hospitalized patients with COVID-19. This was a prospective multicenter study of consecutive COVID-19 patients hospitalized at seven Italian Hospitals from 28 February to 20 April 2020. The study population was divided into two groups according to echocardiographic evidence of RV dysfunction. The primary study outcome was 1-year mortality. The propensity score matching was performed to balance for potential baseline confounders. The study population consisted of 224 patients (mean age 69 \ub1 14, male sex 62%); RV dysfunction was diagnosed in 63 cases (28%). Patients with RV dysfunction were older (75 vs. 67 years, p < 0.001), had higher prevenance of coronary artery disease (27% vs. 11%, p = 0.003), and lower left ventricular ejection fraction (50% vs. 55%, p <0.001). The rate of 1-year mortality (67% vs. 28%; p 64 0.001) was significantly higher in patients with RV dysfunction compared with patients without. After propensity score matching, patients with RV dysfunction showed a worse long-term survival (62% vs. 29%, p <0.001). The multivariable Cox regression model showed an independent association of RV dysfunction with 1-year mortality. RV dysfunction is a relatively common finding in hospitalized COVID-19 patients, and it is independently associated with an increased risk of 1-year mortality
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