48 research outputs found
Structure of a-Si:H/a-Si1-xCx:H multilayers deposited in a reactor with automated substrate holder
This paper deals with the structural properties of a-Si:H/a-Si1-xCx: H multilayers deposited by glow-discharge decomposition of SiH4 and SiH4 and CH4 mixtures. The main feature of the rf plasma reactor is an automated substrate holder. The plasma stabilization time and its influence on the multilayer obtained is discussed. A series of a-Si:H/a-Si1-xCx: H multilayers has been deposited and characterized by secondary ion mass spectrometry (SIMS), X-ray diffraction (XRD) and transmission electron microscopy (TEM). No asymmetry between the two types of interface has been observed. The results show that the multilayers present a very good periodicity and low roughness. The difficulty of determining the abruptness of the multilayer at the nanometer scale is discussed
The SWR1 Histone Replacement Complex Causes Genetic Instability and Genome-Wide Transcription Misregulation in the Absence of H2A.Z
The SWR1 complex replaces the canonical histone H2A with the variant H2A.Z (Htz1 in yeast) at specific chromatin regions. This dynamic alteration in nucleosome structure provides a molecular mechanism to regulate transcription, gene silencing, chromosome segregation and DNA repair. Here we show that genetic instability, sensitivity to drugs impairing different cellular processes and genome-wide transcriptional misregulation in htz1Δ can be partially or totally suppressed if SWR1 is not formed (swr1Δ), if it forms but cannot bind to chromatin (swc2Δ) or if it binds to chromatin but lacks histone replacement activity (swc5Δ and the ATPase-dead swr1-K727G). These results suggest that in htz1Δ the nucleosome remodelling activity of SWR1 affects chromatin integrity because of an attempt to replace H2A with Htz1 in the absence of the latter. This would impair transcription and, either directly or indirectly, other cellular processes. Specifically, we show that in htz1Δ, the SWR1 complex causes an accumulation of recombinogenic DNA damage by a mechanism dependent on phosphorylation of H2A at Ser129, a modification that occurs in response to DNA damage, suggesting that the SWR1 complex impairs the repair of spontaneous DNA damage in htz1Δ. In addition, SWR1 causes DSBs sensitivity in htz1Δ; consistently, in the absence of Htz1 the SWR1 complex bound near an endonuclease HO-induced DSB at the mating-type (MAT) locus impairs DSB-induced checkpoint activation. Our results support a stepwise mechanism for the replacement of H2A with Htz1 and demonstrate that a tight control of this mechanism is essential to regulate chromatin dynamics but also to prevent the deleterious consequences of an incomplete nucleosome remodelling
Controls on explosive-effusive volcanic eruption styles
One of the biggest challenges in volcanic hazard assessment is to understand how and why eruptive style changes within the same eruptive period or even from one eruption to the next at a given volcano. This review evaluates the competing processes that lead to explosive and effusive eruptions of silicic magmas. Eruptive style depends on a set of feedbacks involving interrelated magmatic properties and processes. Foremost of these are magma viscosity, gas loss, and external properties such as conduit geometry. Ultimately, these parameters control the speed at which magmas ascend, decompress and outgas en route to the surface, and thus determine eruptive style and evolution
Efficacy of a self-management plan in exacerbations for patients with advanced COPD
Juan Miguel Sánchez-Nieto,1,2 Rubén Andújar-Espinosa,3 Roberto Bernabeu-Mora,1,2 Chunshao Hu,1 Beatriz Gálvez-Martínez,1 Andrés Carrillo-Alcaraz,1 Carlos Federico Álvarez-Miranda,3 Olga Meca-Birlanga,1 Eva Abad-Corpa4 1Division of Pneumology, Hospital Morales Meseguer, 2University of Murcia, 3Division of Pneumology, Hospital Arrixaca, Murcia, 4Department of Professional Development Unit, Murcia, Spain Background: Self-management interventions improve different outcome variables in various chronic diseases. Their role in COPD has not been clearly established. We assessed the efficacy of an intervention called the self-management program on the need for hospital care due to disease exacerbation in patients with advanced COPD.Methods: Multicenter, randomized study in two hospitals with follow-up of 1 year. All the patients had severe or very severe COPD, and had gone to either an accident and emergency (A&E) department or had been admitted to a hospital at least once in the previous year due to exacerbation of COPD. The intervention consisted of a group education session on the main characteristics of the disease, an individual training session on inhalation techniques, at the start and during the 3rd month, and a written action plan containing instructions for physical activity and treatment for stable phases and exacerbations. We determined the combined number of COPD-related hospitalizations and emergency visits per patient per year. Secondary endpoints were number of patients with visits to A&E and the number of patients hospitalized because of exacerbations, use of antibiotics and corticosteroids, length of hospital stay, and all-cause mortality.Results: After 1 year, the rate of COPD exacerbations with visits to A&E or hospitalization had decreased from 1.37 to 0.89 (P=0.04) and the number of exacerbations dropped from 52 to 42 in the group of patients who received the intervention. The numbers of patients hospitalized, at 19 (40.4%) versus 20 (52.6%) (P=0.26), and those who went to A&E, at 9 (19.1%) versus 14 (36.8%) (P=0.06), due to exacerbation of COPD were also lower in this group. Intake of antibiotics was higher in the intervention group, whereas use of glucocorticoids was slightly lower, though there were no significant differences (P=0.30). There were also no differences between groups in the length of hospital stay (P=0.154) or overall mortality (P=0.191).Conclusion: The implementation of a self-management program for patients with advanced COPD reduced exacerbations that required hospital care. Keywords: self-management, COPD, severe exacerbation
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Giant barocaloric tunability in [(CH<inf>3</inf>CH<inf>2</inf>CH<inf>2</inf>)<inf>4</inf>N]Cd[N(CN)<inf>2</inf>]<inf>3</inf> hybrid perovskite
We report the barocaloric performance of cadmium-dicyanamide perovskite [(CH3CH2CH2)4N]Cd[N(CN)2]3 ([TPrA]Cd[dca]3). The introduction of Cd, a large second-row post-transition metal, into this hybrid organic-inorganic perovskite structure leads to three separate thermally driven phase transitions and four polymorphs, which we characterize in full using temperature-dependent X-ray diffraction and temperature-dependent calorimetry. Amongst these transitions, the non-isochoric orthorhombic to tetragonal phase transition at high temperatures, with a large volume change of ∼0.4%, leads to a large reversible pressure-driven isothermal change in entropy of ∼11.5 J K-1 kg-1, and a giant barocaloric tunability of the transition temperature with pressure of ∼38.2 K kbar-1, which are both desirable for future low-pressure barocaloric cooling applications.The authors are grateful for financial support from Ministerio de Economía y Competitividad MINECO and EU-FEDER (project MAT2017-86453-R), and ERC Starting Grant no 680032. J. M. B. G. acknowledges Xunta de Galicia for a Postdoctoral Fellowship. X. M. is grateful for support from the Royal Society
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Near-room-temperature reversible giant barocaloric effects in [(CH<inf>3</inf>)<inf>4</inf>N]Mn[N<inf>3</inf>]<inf>3</inf>hybrid perovskite
We report giant reversible barocaloric effects in [(CH3)4N]Mn[N3]3 hybrid organic–inorganic perovskite, near its first-order cubic-monoclinic structural phase transition at T0 ∼ 305 K.</p
Improving Skills and Perception in Robot Navigation by an Augmented Virtuality Assistance System
Site-Specific Based Models
This chapter reviews the major conceptual approaches and specifications for the design of Site-Specific Weed Management Decision Support Systems (SSWM-DSS), recent advances in the use of remote and ground platforms and sensors for information gathering and processing and initial experiences translating this information into chemical and physical weed control actuations through decision algorithms and modelsPeer reviewe
Site-Specific Based Models
This chapter reviews the major conceptual approaches and specifications for the design of site-specific weed management decision support systems (SSWM-DSS), recent advances in the use of remote and ground platforms and sensors for information gathering and processing, and initial experiences translating this information into chemical and physical weed control actuations through decision algorithms and models.Peer reviewe