A5001480933- Astrophysics and Star Formation Studies
- Advanced Chemical Physics Studies
- Atmospheric Ozone and Climate
- Atomic and Molecular Physics
- Molecular Spectroscopy and Structure
- Atmospheric chemistry and aerosols
- Mass Spectrometry Techniques and Applications
- Aortic aneurysm repair treatments
- Astro and Planetary Science
- Sinusitis and nasal conditions
- Aortic Disease and Treatment Approaches
- Inorganic Fluorides and Related Compounds
- Health and Wellbeing Research
- Catalysis for Biomass Conversion
- Tuberculosis Research and Epidemiology
- Chemical Synthesis and Reactions
- Catalysts for Methane Reforming
- Boron Compounds in Chemistry
- Ear Surgery and Otitis Media
- Reservoir Engineering and Simulation Methods
- Isotope Analysis in Ecology
- Catalytic Processes in Materials Science
- Sepsis Diagnosis and Treatment
- Carbon dioxide utilization in catalysis
- Hemodynamic Monitoring and Therapy
Pontifical Catholic University of Rio de Janeiro
2017-2021
Universidade Federal do Rio de Janeiro
2012-2020
Centro Universitário Serra dos Órgãos
2005
Bifunctional catalysts of Cu·ZnO supported on modified γ-Al2O3 were prepared and tested in the direct hydrogenation CO2 to methanol dimethyl ether (DME). The modification was carried out using a solution (NH4)2SiF6, aiming incorporate Si atoms alumina structure. metals added support by wet impregnation. characterized Brunauer–Emmett–Teller area, chemical composition, 29Si 27Al magic angle spinning nuclear magnetic resonance, acidity, temperature-programmed reduction. All able convert into...
Nitrous oxide, N2O, is found in the interstellar medium associated with dense molecular clouds and its abundance explained by active chemistry occurring on N2 rich ice surfaces of dust grains. Such regions are being constantly exposed to ionizing radiation that triggers chemical processes which change abundances time. Due non-zero dipole moment, N2O can be used as an important tracer for such well characterization nitrogen content ices outer bodies Solar system. In this work, we...
OBJECTIVE: To define the epidemiological profile and main determinants of morbidity mortality in noncardiac high surgical risk patients Brazil. METHODS: This was a prospective, observational multicenter study. All admitted to intensive care units, i.e., those considered risk, within 1-month period were evaluated monitored daily for maximum 7 days unit determine complications. The 28-day postoperative, hospital rates evaluated. RESULTS: Twenty-nine units participated Surgeries performed...
Acetone, one of the most important molecules in organic chemistry, also a precursor prebiotic species, was found interstellar medium associated with star-forming environments. The mechanisms proposed to explain gas phase abundance acetone are based on grain mantle chemistry. High energy photons coming from stellar radiation field nearby stars interact ice mantles dust grains leading photoionization, photodissociation, and photodesorption processes. In this work we investigate photostability...
Non-thermal desorption by electron impact constitutes an important route which neutral and ionic fragments from simple nitrile-bearing ices may be delivered back to the gas-phase of astrophysical environments, contributing production more complex molecules.
The organic compounds HCN and C2H2, present in protoplanetary discs, may react to form precursor molecules of the nucleobases, such as pyrimidine molecule, C4H4N2. Depending on temperature a given region disc, are gas phase or condensed grain surfaces. action X-ray photons MeV protons, emitted by young central star, lead several physical chemical processes pre-stellar environments. In this work we have experimentally investigated ionization, dissociation desorption stimulated soft X-rays...
The desorption process induced by photons, electrons, or ions onto icy surfaces is an important mechanism for leading neutral ionized molecular species to the gas phase in interstellar and circumstellar environments. In this work, we report results of high energy electron impact a condensed pyrimidine ice means electron-stimulated ion (ESID). Desorbed cations from surface were analyzed time-of-flight mass spectrometry (TOF-MS). most abundant desorbed are H+ H2+, although several other...
Methanol and ethanol, precursors of prebiotic molecules, are found in interstellar circumstellar environments. At low temperatures, electrons may interact with these frozen molecules on dust grain surfaces stimulating desorption atomic molecular ions charged clusters. These heavy fragments released from the icy mantles could contribute to abundance gas phase organic such In this work, we investigate ionic desorbed methanol ethanol pure ices due high energy electron impact. Absolute yields...
In cold core of dark molecular clouds, where the UV radiation from external sources is strongly attenuated, cosmic rays can induce chemical reactions on surface ice-covered grains promoting ejection processed material to gas phase. We report positive and negative secondary ion emission pure CH3CN, C2H3CN i-C3H7CN ices due bombardment heavy ions (252Cf fission fragments), simulating incidence onto icy surfaces. The emitted each sample were analysed by time-of-flight mass spectrometry...
The room temperature dissociative recombination of ions formed in an acetone/argon plasma has been studied using the flowing afterglow Langmuir probe-mass spectrometer method. By changing concentration acetone density, it is possible to have a dominated by different types (fragments, adducts, and dimer ions). application these measurements astrophysical plasmas discussed.
The aldol condensation between furfural and acetone was studied in the presence of organic bases, such as Piperazine (PIP), 3-Aminopropyltriethoxysilane (APTES) 1,5,7-Triazabicyclo [4.4.0] dec-5-ene (TBD), basic catalysts.The latter base showed highest conversion rates high selectivity to single-condensation product 4-(2-Furyl)-3-buten-2-on (F-Ac).These data are consistent with greater basicity TBD relation other amines.This study carried out aiming at future anchoring bases inorganic...
Methyl cyanide (CH3CN) is the simplest organic nitrile and it found in almost all astrophysical environments, including cometary comae, Titan's atmosphere interstellar medium (ISM), especially starforming regions hot cores. In this work, role of ion desorption caused by electron collisions onto a CH3CN ice discussed. New ionic species, clusters are produced, pointing to delivery more complex species from surfaces gas-phase ISM.
The photoionization and the photodissociation of pyrimidine in condensed phase due to soft X-ray interaction were experimentally investigated. measurements performed at Brazilian Synchrotron Light Source (LNLS), operated single-bunch mode, employing photons energies around C1s (288 eV) N1s (400 resonances. Mass spectra ionic fragments desorbed from ice obtained using time-of-flight mass spectrometry (TOF-MS). photodesorption yields (ions photons−1) ion (cm−3 s−1) determined, providing data...
We have employed soft X-ray photons at the oxygen 1s-edge and variable energy electrons to simulate effects of stellar radiation field on astrophysics ices. Several ionic fragments been identified their desorption rate per impact determined, providing data astrochemistry models. This study helped understand how some precursor species are formed qualitatively quantitatively by determining photodesorption ion yields, pointing out important role in evolution molecular abundance complexity...
Objective To describe a case of frontal sinus cholesteatoma and review the characteristics this pathology. Method Case report: 32‐year‐old white man. First symptoms: pressure, proptosis left eye with downward displacement (no visual symptoms or movement impairment). ENT examination nasal endoscopy were normal. CT paranasal sinuses: large mass in sinus, destruction orbital cranial blades. Results An endoscopic approach was attempted no success. Nothing could be extracted from sinus. Therefore...
The aim of the present study was to investigate detection percentage tuberculosis among patients that are respiratory symptomatic (TB suspects). In this work, we preliminary results research carried out at "Hospital das Clínicas de Teresópolis Costantino Ottaviano da Fundacao Educacional Serra dos Orgãos (FESO)" from November 2003 April 2004. Among 40 individuals identified and referred Tuberculosis Control Program in , two (5.0%) were characterized as smear-positive. These confirm reports...
Abstract Background A methodology to identify patients with ascending aortic aneurysm (AsAA) under high risk of growth is not completely defined. Objective This research seeks numerically characterize the blood flow and relate resulting stress distribution AsAA growth. Methods Analytical, observational, single-center study in which a computational fluid dynamics (CFD) protocol was applied Computed Tomography Angiogram (CTA) images AsAA. Two exams at least one year difference were obtained....