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1.
J Synchrotron Radiat ; 29(Pt 5): 1209-1215, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-36073879

RESUMO

A newly designed setup to perform steady-state X-ray excited optical luminescence (XEOL) spectroscopy and simultaneous XEOL and X-ray absorption spectroscopy characterization at beamline P65 of PETRA III is described. The XEOL setup is equipped with a He-flow cryostat and state-of-the-art optical detection system, which covers a wide wavelength range of 300-1700 nm with a high spectral resolution of 0.4 nm. To demonstrate the setup functioning, low-temperature XEOL studies on polycrystalline CuInSe2 thin film, single-crystalline GaN thin film and single-crystalline ZnO bulk semiconductor samples are performed.

2.
Rev Sci Instrum ; 92(6): 063903, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34243590

RESUMO

We present a new autoclave that enables in situ characterization of hydrothermal fluids at high pressures and high temperatures at synchrotron x-ray radiation sources. The autoclave has been specifically designed to enable x-ray absorption spectroscopy in fluids with applications to mineral solubility and element speciation analysis in hydrothermal fluids in complex compositions. However, other applications, such as Raman spectroscopy, in high-pressure fluids are also possible with the autoclave. First experiments were run at pressures between 100 and 600 bars and at temperatures between 25 °C and 550 °C, and preliminary results on scheelite dissolution in fluids of different compositions show that the autoclave is well suited to study the behavior of ore-forming metals at P-T conditions relevant to the Earth's crust.

3.
Sci Rep ; 11(1): 524, 2021 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-33436754

RESUMO

Band structure tailoring has been a great avenue to achieve the half-metallic electronic ground state in materials. Applying this approach to the full Heusler alloy Fe2TiSn, Cr is introduced systematically at Ti site that conforms to the chemical formula [Formula: see text]Sn. Compositions so obtained have been investigated for its electronic, magnetic, and electrical transport properties with an aim to observe the half-metallic ferromagnetic ground state, anticipated theoretically for Fe2CrSn. Our experimental study using synchrotron X-ray diffraction reveals that only compositions with [Formula: see text] 0.25 yield phase pure L2[Formula: see text] cubic structures. The non-magnetic ground state of Fe2TiSn gets dramatically affected upon inclusion of Cr giving rise to a localized magnetic moment in the background of Ruderman-Kittel-Kasuya-Yosida (RKKY) correlations. The ferromagnetic interactions begin to dominate for x = 0.25 composition. Results of its resistivity and magnetoresistance (MR) measurement point towards a half-metallic ground state. The calculation of exchange coupling parameter, [Formula: see text], and orbital projected density of states that indicate a change in hybridization between 3d and 5p orbital, support the observations made from the study of local crystal structure made using the extended X-ray absorption fine structure spectroscopy. Our findings here highlight an interesting prospect of finding half-metallicity via band structure tailoring for wide application in spintronics devices.

4.
J Hazard Mater ; 329: 131-140, 2017 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-28131040

RESUMO

The surface chemistry and bulk chemical speciation of solid industrial wastes containing 8wt-% antimony (Sb) were investigated using synchrotron X-ray Absorption Near Edge Structure (XANES) and Time-of-Flight Ion Secondary Mass Spectrometry (ToF-SIMS). Leaching experiments were conducted in order to better understand the behavior of Sb in waste streams and to inform regulatory management of antimony-containing wastes. The experiments also demonstrate how a combination of XANES and ToF-SIMS adds value to the field of waste investigations. Leaching treatments (acid and base) were performed at a synchrotron over 24h time periods. Surface analyses of the wastes before leaching showed the presence of Sb associated with S and O. Bulk analyses revealed Sb to be present, primarily, as trivalent sulfide species. Both acid and base leaching did not change the antimony speciation on the solid. Leaching transferred about 1% of the total Sb into solution where Sb was found to be present as Sb(V). XANES data showed similarities between leachate and FeSbO4. During base leaching, the Sb content in solution gradually increased over time, and potential desorption mechanisms are discussed.

5.
J Gynecol Obstet Biol Reprod (Paris) ; 45(4): 407-13, 2016 Apr.
Artigo em Francês | MEDLINE | ID: mdl-26321610

RESUMO

Heart diseases complicate 1 to 3% of pregnancies and are the leading cause of indirect maternal deaths. Prior ischaemic heart event in pregnant patients is increasing. Most knowledge is based on few reports and there are no French nor international recommendations about the specific management of these patients. The specificity of the management of these patients during pregnancy, delivery and post-partum depends on the severity of the prior cardiac event and its consequences. This will be illustrated by the report of four recent cases managed in our hospital. First patient had myocardial infarction with normal left ventricular ejection fraction (LVEF). Second patient had a Tako-Tsubo syndrome with LVEF 45%. Third patient had ischemic cardiopathy with LVEF 30%. Fourth patient had myocardial infarction with LVEF 20%. A multidisciplinary follow-up should be required, especially in patients with severe ventricular dysfunction. The risk of fetal growth restriction appears to be increased, suggesting that closer ultrasound monitoring is necessary.


Assuntos
Isquemia Miocárdica/terapia , Complicações Cardiovasculares na Gravidez/terapia , Adulto , Feminino , Humanos , Gravidez
6.
Gynecol Obstet Fertil ; 42(12): 832-7, 2014 Dec.
Artigo em Francês | MEDLINE | ID: mdl-25458806

RESUMO

OBJECTIVES: A retrospective monocentric clinical trial was performed to evaluate the efficacy of the association of mifepristone and misoprostol for the management of early pregnancy failure. PATIENTS AND METHODS: Ninety-two women with early pregnancy failure or anembryonic pregnancy were first treated with 600 mg of mifepristone and 48 hours later with 400 µg of misoprostol by oral administration. Successful treatment, defined as an empty uterus, was searched at day 3, with the association of misoprostol-mifepristone alone or with complementary medical treatment, prostaglandins or ocytocine. RESULTS: The overall treatment success was 82% (75 of 92 women) with 69 successful cases at day 3 (75%). Six of 92 women (7%) needed a second-line medical treatment. For the last 17 women (18%), the failure of the associated tested medical treatment lead to a secondary surgery. No prognostic factor for the successful medical treatment has been highlighted. DISCUSSION AND CONCLUSION: A high efficacy for the management of early pregnancy failure is demonstrated for the mifepristone and misoprostol medical treatment. The specific contribution of mifepristone, although proven in the cases of termination of evolutive pregnancies, should be further evaluated in the future for the specific management of early pregnancy failure. Nevertheless, no prognostic factor for the success of the propose treatment can be determined, as the amount of patients enrolled in this study was not sufficient.


Assuntos
Aborto Espontâneo/tratamento farmacológico , Mifepristona/administração & dosagem , Misoprostol/administração & dosagem , Adulto , Quimioterapia Combinada , Feminino , Idade Gestacional , Humanos , Ocitócicos , Gravidez , Primeiro Trimestre da Gravidez , Estudos Retrospectivos , Resultado do Tratamento
7.
J Gynecol Obstet Biol Reprod (Paris) ; 42(2): 117-22, 2013 Apr.
Artigo em Francês | MEDLINE | ID: mdl-22459804

RESUMO

Mastocytosis is a rare disorder characterized by an accumulation of mastocytes in cutaneous and visceral tissues. In the presence of stimuli such as stress, pain, drug administration and cutaneous compression, it can ultimately lead to cardiovascular collapse. In women with mastocytosis, pregnancy monitoring and pain management in the peripartum period can be challenging and should involve a multidisciplinary approach. In this article, we discuss our ante partum care and intra partum management, as illustrated by three recent cases.


Assuntos
Mastocitose/complicações , Complicações na Gravidez/terapia , Adulto , Analgesia Obstétrica , Doenças Cardiovasculares/etiologia , Feminino , Ruptura Prematura de Membranas Fetais , Humanos , Masculino , Mastocitose/terapia , Mastocitose Cutânea/complicações , Mastocitose Cutânea/terapia , Mastocitose Sistêmica/complicações , Mastocitose Sistêmica/terapia , Ocitócicos/administração & dosagem , Ocitocina/administração & dosagem , Manejo da Dor , Gravidez , Resultado da Gravidez , Cuidado Pré-Natal/métodos
8.
J Synchrotron Radiat ; 19(Pt 1): 126-8, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22186653

RESUMO

Spray deposition of thin films and coatings is a widely used manufacturing process owing to its low cost, versatility and simple implementation. The objective of the presented experiments was to investigate whether X-ray absorption measurements on solutes carried by aerosols are possible, and what count rates can be achieved depending on solution flow through and the resulting mass density in the interrogation volume. The investigated prototypical spray aerosol was InCl(3) dissolved in water or ethanol dispersed via an ultrasonic nebulizer. InCl(3) spray is essential for the ion layer gas reaction process used for the deposition of In(2)S(3) buffer layers for highly efficient chalcopyrite solar cells. The discussed experiments demonstrate that measurements are possible, but that the achievement of good signal-to-noise ratios requires extended sampling times and concentrated solutions.

9.
Nanotechnology ; 20(20): 204003, 2009 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-19420651

RESUMO

Reactive hydride composites (RHCs) are very promising hydrogen storage materials for future applications due to their reduced reaction enthalpies and high gravimetric capacities. At present, the materials' functionality is limited by the reaction kinetics. A significant positive influence can be observed with addition of transition-metal-based additives. To understand the effect of these additives, the chemical state and changes during the reaction as well as the microstructural distribution were investigated using x-ray absorption near-edge structure (XANES) spectroscopy and anomalous small-angle x-ray scattering (ASAXS). In this work, zirconium- and vanadium-based additives were added to 2LiBH4-MgH2 composites and 2LiH-MgB2 composites and measured in the vicinity of the corresponding absorption edge. The measurements reveal the formation of finely distributed zirconium diboride and vanadium-based nanoparticles. The potential mechanisms for the observed influence on the reaction kinetics are discussed.


Assuntos
Hidrogênio/química , Hidrogênio/isolamento & purificação , Modelos Químicos , Nanoestruturas/química , Nanotecnologia/métodos , Vanádio/química , Zircônio/química , Simulação por Computador , Fontes de Energia Elétrica , Nanoestruturas/ultraestrutura , Tamanho da Partícula
10.
J Chem Phys ; 129(21): 214502, 2008 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-19063564

RESUMO

A systematic and detailed investigation of the structure of As(x)Te(100-x) glasses (20

11.
Talanta ; 75(5): 1284-92, 2008 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-18585214

RESUMO

Time-resolved synchrotron X-ray absorption near edge structure (XANES) spectroscopy was used to study changes of chromium speciation in soils upon soil-water interaction. The time resolution was 30-45 min. In a flow-column apparatus operated near the synchrotron beamline, two different types of soil were treated with potassium-dichromate solution, and soil samples were taken and directly analysed by XANES. The results provide insight into different equilibrium times of a few hours, depending on the type of soil. The XANES speciation analyses, based on a model comprising insoluble Cr(III) and Cr(VI) compounds, show how the fate of Cr species on soils can be followed close to real-time. Since the method allowed the soils to be investigated close to real-time, sampling in the field and preservation before analysis were made redundant. This study benefits the development of corresponding in situ remediation techniques.


Assuntos
Cromo/análise , Poluentes do Solo/análise , Espectrometria por Raios X/métodos , Cromo/química , Dicromato de Potássio/química , Sensibilidade e Especificidade , Poluentes do Solo/química , Soluções/química , Fatores de Tempo
12.
Environ Sci Technol ; 39(20): 8038-44, 2005 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-16295872

RESUMO

Several recent investigations have shown encouraging potential for the removal of arsenic (As) from groundwater by granular zerovalent iron (Fe0). In contrast to previous studies conducted, we have investigated the applicability of this method and the nature of As bonding under conditions with dissolved sulfide. Three column tests were performed over the period of 1 year using solutions with either As(V) or As(II) (2-200 mg/L) in the input solution. Arsenic outflow concentrations decreased from initially 30-100 microg/L to concentrations of below 1 microg/L with time. XANES (X-ray absorptions near edge structure) and EXAFS (expanded X-ray absorption fine structure) spectra indicated that As in the solid phase is not only directly coordinated with oxygen, as is the case in adsorbed or coprecipitated arsenite and arsenate. Samples with high sulfur content showed additional bonding, for which Fourier transformations of EXAFS data exhibited a peak between 2.2 and 2.4 A. This bonding most likely originated from the direct coordination of sulfur or iron with As, which was incorporated in iron sulfides orfrom adsorbed thioarsenites. The formation of this sulfide bonding supports the removal of As by Fe0 because sulfide production by microbial sulfate reduction is ubiquitous in permeable reactive barriers composed of Fe0.


Assuntos
Arsênio/química , Água Doce/química , Ferro/química , Sulfetos/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Arsênio/análise , Purificação da Água/instrumentação , Difração de Raios X
13.
Fresenius J Anal Chem ; 371(6): 823-30, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11768472

RESUMO

The chemical processes that occur during sequential extraction of a highly Pb-contaminated soil sample were investigated using XAFS spectroscopy for the identification of the Pb species in the solid residues after each step. The sequential extraction was performed following the procedure described by Salomons and Förstner. It was found that during the sequential extraction serious alteration of the chemical binding forms of the Pb occurs. The most important processes underlying the chemical changes are the re-adsorption of solubilized Pb ions by soil matrix components and the precipitation of insoluble Pb species with anions from the extractant.


Assuntos
Artefatos , Chumbo/análise , Poluentes do Solo/análise , Alemanha , Microscopia Eletrônica de Varredura , Solubilidade , Espectrometria por Raios X
14.
Chirurgia (Bucur) ; 45(6): 311-2, 1996.
Artigo em Romano | MEDLINE | ID: mdl-9110966

RESUMO

The experimental study (on rabbits and dogs) and the clinical study followed one layer sutures performed with eversing or inversing separate stitches, with ordinary or nontraumatic needles or mechanical sutures. Sutures were performed on oesophagus, stomach, small and large bowel. Excepting the oeso-jejunal or ileo-colic anastomosis (termino-lateral), the majority of sutures were used to accomplish termino-terminal anastomosis. The results were improved using high-quality materials (resistant, nonhygroscopical, resorbable threads), on correctly evacuated digestive tract, under antibiotic protection, avoiding perioperative hemodynamic fluctuations, with a complex postoperative care and a gradual renutrition.


Assuntos
Procedimentos Cirúrgicos do Sistema Digestório , Técnicas de Sutura , Suturas , Animais , Cães , Humanos , Coelhos , Grampeadores Cirúrgicos
15.
Proc Natl Acad Sci U S A ; 88(8): 3019-23, 1991 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-1826558

RESUMO

Upon activation of human neutrophils, C3b receptors (type 1 complement receptors, CR1) are rapidly translocated from an intracellular pool to the surface, increasing plasma membrane expression 6- to 10-fold. This is followed by reinternalization and degradation of the receptors, even in the absence of ligand. Upregulation of surface CR1 may occur without exocytosis of primary or secondary granules, and intracellular CR1 in resting neutrophils does not sediment with these granules on density gradient fractionation. To directly localize the intracellular pools of CR1, we used immunoelectron microscopy of fixed, permeabilized cells. In resting neutrophils, CR1 is associated with the membranes of smooth-surfaced, empty-appearing vesicles whose irregular borders clearly distinguish them from primary and secondary granules. After activation by fMet-Leu-Phe, the intracellular pool is primarily found in large, conspicuous, multivesicular bodies. These bodies also incorporate colloidal gold from the extracellular fluid, suggesting that they are formed by endocytosis. Thus, the sites in which CR1 is stored in resting cells, and recycled in activated cells, are structurally unique and morphologically distinguishable.


Assuntos
Neutrófilos/metabolismo , Receptores de Complemento/metabolismo , Compartimento Celular , Membrana Celular/metabolismo , Endocitose , Humanos , Membranas Intracelulares/metabolismo , Microscopia Eletrônica , N-Formilmetionina Leucil-Fenilalanina/farmacologia , Neutrófilos/ultraestrutura , Organelas/metabolismo , Receptores de Complemento 3b
16.
Neuroscience ; 45(2): 467-77, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-1722291

RESUMO

Plasmalemmal fractions from cultured astrocytes have been used as the immunogen in generating a monoclonal antibody, termed 8C10, which binds to the surface of cultured astrocytes of the rat. 8C10 immunoreactivity is present on the membrane surface of cultured type 1 astrocytes, type 2 astrocytes, oligodendrocytes, meningeal cells, and 02A progenitor cells, and it persists after aldehyde fixation. The antibody also stains aldehyde-fixed central nervous system, in a pattern which suggests that the plasma membranes of fine astrocytic processes in adult neuropil express the epitope. Astrocytic perikarya and processes in white matter are also stained, but there is no immunoreactivity present in neuronal processes or perikarya. Astrocytic processes in developing cerebellar cortex are stained at postnatal ages when some of these processes are guiding the migration of neuronal perikarya.


Assuntos
Antígenos de Superfície/imunologia , Astrócitos/imunologia , Epitopos/imunologia , Animais , Animais Recém-Nascidos , Anticorpos Monoclonais/imunologia , Astrócitos/citologia , Biomarcadores , Diferenciação Celular , Células Cultivadas , Córtex Cerebelar/citologia , Córtex Cerebelar/crescimento & desenvolvimento , Córtex Cerebral/citologia , Endotélio Vascular/citologia , Proteína Glial Fibrilar Ácida/análise , Meninges/citologia , Especificidade de Órgãos , Ratos , Ratos Endogâmicos
20.
J Occup Med ; 20(8): 535-8, 1978 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-690737

RESUMO

A high speed automated machining process on gray iron has been functioning over a period of 70 months with a variety of coolant-lubricant-additives used. The author followed 118 employees for variable lengths of time, with 12 having a 70-month exposure period. To date, no significant chest x-ray, pulmonary function, lung cytology, or liver function abnormalities have been discovered. Any respiratory symptomatology seems to be related to either smoking or preexisting respiratory pathology. This is the initial report of an on-going surveillance program.


Assuntos
Poluentes Ocupacionais do Ar/efeitos adversos , Poluentes Atmosféricos/efeitos adversos , Lubrificação , Óleo Mineral/efeitos adversos , Física , Poluentes Ocupacionais do Ar/análise , Alanina Transaminase/sangue , Aspartato Aminotransferases/sangue , Humanos , Fígado/enzimologia , Masculino , Óleo Mineral/análise , Fenômenos Físicos , Capacidade Vital
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