2,404 research outputs found
Real-space study of the growth of magnesium on ruthenium
The growth of magnesium on ruthenium has been studied by low-energy electron
microscopy (LEEM) and scanning tunneling microscopy (STM). In LEEM, a
layer-by-layer growth is observed except in the first monolayer, where the
completion of the first layer in inferred by a clear peak in electron
reflectivity. Desorption from the films is readily observable at 400 K.
Real-space STM and low-energy electron diffraction confirm that sub-monolayer
coverage presents a moir\'e pattern with a 1.2 nm periodicity, which evolves
with further Mg deposition by compressing the Mg layer to a 2.2 nm periodicity.
Layer-by-layer growth is followed in LEEM up to 10 ML. On films several ML
thick a substantial density of stacking faults are observed by dark-field
imaging on large terraces of the substrate, while screw dislocations appear in
the stepped areas. The latter are suggested to result from the mismatch in
heights of the Mg and Ru steps. Quantum size effect oscillations in the
reflected LEEM intensity are observed as a function of thickness, indicating an
abrupt Mg/Ru interface.Comment: 21 pages, 10 figure
Oligosacáridos utilizados para inhibir la mitosis de los astrocitos y de las células tumorales del sistema nervioso; y procedimiento de obtención de estos oligosacáridos
Traducción de Patente Europea E92923821 (fecha de solicitud, 13/11/1992).-- Prioridad: ES199111139102522.-- Titular: Consejo Superior de Investigaciones Científicas (CSIC).La invención se refiere a oligosacáridos y a preparaciones medicinales que contienen ingredientes
orgánicos activos.Peer reviewe
Magnetism in nanometer-thick magnetite
The oldest known magnetic material, magnetite, is of current interest for use
in spintronics as a thin film. An open question is how thin can magnetite films
be and still retain the robust ferrimagnetism required for many applications.
We have grown one-nanometer-thick magnetite crystals and characterized them in
situ by electron and photoelectron microscopies including selected-area x-ray
circular dichroism. Well-defined magnetic patterns are observed in individual
nano-crystals up to at least 520 K, establishing the retention of
ferrimagnetism in magnetite two-unit-cells thick.Comment: 5 pages, 4 figure
Hydrogen-induced reversible spin-reorientation transition and magnetic stripe domain phase in bilayer Co on Ru(0001)
Imaging the change in the magnetization vector in real time by spin-polarized
low-energy electron microscopy, we observed a hydrogen-induced, reversible
spin-reorientation transition in a cobalt bilayer on Ru(0001). Initially,
hydrogen sorption reduces the size of out-of-plane magnetic domains and leads
to the formation of a magnetic stripe domain pattern, which can be understood
as a consequence of reducing the out-of-plane magnetic anisotropy. Further
hydrogen sorption induces a transition to an in-plane easy-axis. Desorbing the
hydrogen by heating the film to 400 K recovers the original out-of-plane
magnetization. By means of ab-initio calculations we determine that the origin
of the transition is the local effect of the hybridization of the hydrogen
orbital and the orbitals of the Co atoms bonded to the absorbed hydrogen.Comment: 5 figure
Magnetism in nanometer-thick magnetite
The oldest known magnetic material, magnetite, is of current interest for use in spintronics as a thin film. An open question is how thin can magnetite films be and still retain the robust ferrimagnetism required for many applications. We have grown 1-nm-thick magnetite crystals and characterized them in situ by electron and photoelectron microscopies including selected-area x-ray circular dichroism. Well-defined magnetic patterns are observed in individual nanocrystals up to at least 520 K, establishing the retention of ferrimagnetism in magnetite two unit cells thick
Guia prático para usar o modulo intercâmbio (importação e exportação) do Alelo vegetal.
O intercâmbio de germoplasma vegetal, em suas mais diferentes formas (sementes, embriões, plântulas, estacas, borbulhas, pólen), tem papel fundamental no Brasil para a segurança alimentar, o agronegócio e a pesquisa. A Embrapa Recursos Genéticos e Biotecnologia, em cumprimento das disposições legais designadas pelo Ministério da Agricultura e Pecuária, atende ao Sistema Nacional de Pesquisa Agropecuária na demanda por importação e exportação de germoplasma vegetal, bem como nos procedimentos quarentenários do material. A documentação referente a cada processo de intercâmbio e sua disponibilização para rastreamento e acompanhamento são possíveis graças ao desenvolvimento do Alelo – Intercâmbio Vegetal da Embrapa. Nesta publicação da série Embrapa Documentos, estão descritas as etapas necessárias para o cumprimento do fluxo de intercâmbio de germoplasma vegetal
An Innovative Photoreactor, FluHelik, To Promote UVC/H2O2 Photochemical Reactions: Tertiary Treatment of an Urban Wastewater
This is the accepted manuscript of the following article: Espíndola et al. Science of the Total Environment, 2019, 667, 197-207. https://doi.org/10.1016/j.scitotenv.2019.02.335An innovative photoreactor, FluHelik, was used to promote the degradation of contaminants of emerging concern (CECs) by a photochemical UVC/H2O2 process. First, the system was optimized for the oxidation of a model antibiotic, oxytetracycline (OTC), using both ultrapure water (UPW) and a real urban wastewater (UWW) (collected after secondary treatment) as solution matrices. Following, the process was evaluated for the treatment of a UWW spiked with a mixture of OTC and 10 different pharmaceuticals established by the Swiss legislation at residual concentrations (∑CECs <660 μg L−1). The performance of the FluHelik reactor was analyzed both at lab and pre-pilot scale in multiple and single pass flow modes.
The efficiency of the FluHelik photoreactor, at lab-scale, was evaluated at different operational conditions (H2O2 concentration, UVC lamp power (4, 6 and 11 W) and flow rate) and further compared with a conventional Jets photoreactor. Both photoreactors exhibited similar OTC removal efficiencies at the best conditions; however, the FluHelik reactor showed to be more efficient (1.3 times) in terms of mineralization when compared with the Jets reactor. Additionally, the efficiency of the UVC/H2O2 photochemical system using the FluHelik photoreactor in reducing the toxicity of the real effluent containing 11 pharmaceuticals was evaluated through zebrafish (Danio rerio) embryo toxicity bioassays. FluHelik scale-up from laboratory to pre-pilot to promote UVC/H2O2 photochemical process proved to be feasibleThis work was financially supported by: Associate Laboratory LSRE-LCM - UID/EQU/50020/2019 - funded by national funds through FCT/MCTES (PIDDAC). V.J.P. Vilar acknowledges the FCT Investigator 2013 Programme (IF/00273/2013). J.C.A. Espíndola acknowledges CNPq (Brazil) for his scholarship (205781/2014-4). R. Montes, R. Rodil and J.B. Quintana acknowledge the financial support of Spanish "Agencia Estatal de Investigación" (ref. CTM2017-84763-C3-R-2) and Xunta de Galicia (ref. ED431C2017/36), both confounded by FEDER/ERDFS
Aquaporin-4 Antibodies Are Not Related to HTLV-1\ud Associated Myelopathy
Introduction: The seroprevalence of human T-cell leukemia virus type 1 (HTLV-1) is very high among Brazilians (,1:200).\ud
HTLV-1 associated myelopathy or tropical spastic paraparesis (HAM/TSP) is the most common neurological complication of\ud
HTLV-1 infection. HAM/TSP can present with an acute/subacute form of longitudinally extensive myelitis, which can be\ud
confused with lesions seen in aquaporin-4 antibody (AQP4-Ab) positive neuromyelitis optica spectrum disorders (NMOSD)\ud
on MRI. Moreover, clinical attacks in patients with NMOSD have been shown to be preceded by viral infections in around\ud
30% of cases.\ud
Objective: To evaluate the frequency of AQP4-Ab in patients with HAM/TSP. To evaluate the frequency of HTLV-1 infection\ud
in patients with NMOSD.\ud
Patients and Methods: 23 Brazilian patients with HAM/TSP, 20 asymptomatic HTLV-1+ serostatus patients, and 34 with\ud
NMOSD were tested for AQP4-Ab using a standardized recombinant cell based assay. In addition, all patients were tested for\ud
HTLV-1 by ELISA and Western blotting.\ud
Results: 20/34 NMOSD patients were positive for AQP4-Ab but none of the HAM/TSP patients and none of the\ud
asymptomatic HTLV-1 infected individuals. Conversely, all AQP4-Ab-positive NMOSD patients were negative for HTLV-1\ud
antibodies. One patient with HAM/TSP developed optic neuritis in addition to subacute LETM; this patient was AQP4-Ab\ud
negative as well. Patients were found to be predominantly female and of African descent both in the NMOSD and in the\ud
HAM/TSP group; Osame scale and expanded disability status scale scores did not differ significantly between the two\ud
groups.\ud
Conclusions: Our results argue both against a role of antibodies to AQP4 in the pathogenesis of HAM/TSP and against an\ud
association between HTLV-1 infection and the development of AQP4-Ab. Moreover, the absence of HTLV-1 in all patients\ud
with NMOSD suggests that HTLV-1 is not a common trigger of acute attacks in patients with AQP4-Ab positive NMOSD in\ud
populations with high HTLV-1 seroprevalence.This study received financial support from the Brazilian government agencies FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo - www. fapesp.br/en) and CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - www.capes.gov.br). The work of S.J. and B.W. was supported by research grants from Bayer Schering Healthcare and from Merck Serono. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Plasmacytoid dendritic cells are increased in cerebrospinal fluid of untreated patients during multiple sclerosis relapse
The plasmacytoid dendritic cells (pDCs) express a high level of Toll-like receptor 9 (TLR-9), which recognizes viral DNA. Activated via TLR-9, pDCs also secrete large amounts of type I interferon which are involved either in stimulation or down regulation of immune response in multiple sclerosis (MS). In the present study, we determinate pDCs levels by flow cytometry in Cerebrospinal Fluid (CSF) and Peripheral Blood from MS patients in relapsing and in remitting phases of the disease, comparing with other non-inflammatory diseases (OND). We provide evidence that MS patients in relapse without any treatment have a significantly (p < 0.01) higher percentage of pDCs in CSF than do patients in remission or those with OND. No change in the percentage of pDCs was observed in the peripheral blood of any of these patients. The increase of pDCs in central nervous system during relapse may be explained either by a virus infection or a down regulatory process
Percutaneous mitral valve repair : Outcome improvement with operator experience and a second-generation device
Background and aim: Recent randomized data comparing percutaneous mitral valve repair (PMVR) versus optimal medical treatment in patients with functional MR (FMR) seemed to highlight the importance of the learning curve not only for procedural outcomes but also for patient selection. The aim of the study was to compare a contemporary series of patients undergoing PMVR using a second-generation Mitraclip device (Mitraclip NT) with previous cohorts treated with a first-generation system. Methods: This multicenter study collected individual data from 18 centers between 2012 and 2017. The cohort was divided into three groups according to the use of the first-generation Mitraclip during the first (control-1) or second half (control-2) or the Mitraclip NT sys-tem. Results: A total of 545 consecutive patients were included in the study. Among all, 182 (33.3%), 183 (33.3%), and 180 (33.3%) patients underwent mitral repair in the control-1, control-2, and NT cohorts, respectively. Procedural success was achieved in 93.3% of patients without differences between groups. Major adverse events did not statistically differ among groups, but there was a higher rate of pericardial effusion in the control-1 group (4.3%, 0.6%, and 2.6%, respectively; p = 0.025). The composite endpoint of death, surgery, and admission for congestive heart failure (CHF) at 12 months was lower in the NT group (23.5% in control-1, 22.5% in control-2, and 8.3% in the NT group; p = 0.032). Conclusions: The present paper shows that contemporary clinical outcomes of patients undergoing PMVR with the Mitraclip system have improved over time
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