Search results for " circulation"

Carbon-doped titania as a precursor for titanate nanotubes

2018

Carbon-doped titania was fabricated via carbothermal treatment in nitrogen–acetylene gas flow and further used as a precursor for multiwalled titanate nanotube (TNT) synthesis via alkaline hydrothermal route. Investigation of the reaction products after hydrothermal treatment of carbon-doped titania using Transmission electron microscopy, X-ray diffraction, and Brunauer–Emmett–Teller method shows the successful formation of TNTs. The presence of carbon was proved although the type of incorporation could not be certified. All samples show approximately the same carbon content before and after hydrothermal treatment. An increasing pretreatment temperature of titania precursor powders yields m…

Sensitivity Analysis of the MASLWR Helical Coil Steam Generator Using TRACE

2011

Accurate simulation of transient system behavior of a nuclear power plant is the goal of systems code calculations, and the evaluation of a code's calculation accuracy is accomplished by assessment and validation against appropriate system data. These system data may be developed either from a running system prototype or from a scaled model test facility, and characterize the thermal hydraulic phenomena during both steady state and transient conditions. The identification and characterization of the relevant thermal hydraulic phenomena, and the assessment and validation of thermal hydraulic systems codes, has been the objective of multiple international research programs. The validation and…

Luminescence Properties of ZnO Nanocrystals and Ceramics

2008

The luminescence excitation spectra, luminescence spectra and the nanosecond-scale decay kinetics were studied. The ZnO and ZnO:Al nanopowders were prepared by vaporization-condensation in a solar furnace using different raw powders: commercial, hydrothermal and those obtained by plasma synthesis. Exciton-phonon as well as exciton-exciton interaction processes in nanopowders, a bulk crystal and ZnO ceramics were studied and compared. The fast decay and low afterglow intensity of ZnO nanopowders and ceramics support these materials for scintillators.

Magnetic resonance imaging of dissolved hyperpolarized 129Xe using a membrane-based continuous flow system.

2009

Abstract A technique for continuous production of solutions containing hyperpolarized 129Xe is explored for MRI applications. The method is based on hollow fiber membranes which inhibit the formation of foams and bubbles. A systematic analysis of various carrier agents for hyperpolarized 129Xe has been carried out, which are applicable as contrast agents for in vivo MRI. The image quality of different hyperpolarized Xe solutions is compared and MRI results obtained in a clinical as well as in a nonclinical MRI setting are provided. Moreover, we demonstrate the application of 129Xe contrast agents produced with our dissolution method for lung MRI by imaging hyperpolarized 129Xe that has been…

Evolution de la circulation oécanique profonde durant le Crétacé : apport des isotopes du néodyme

2014

The Cretaceous is depicted as the warmest period of the last 300 Ma. The oceanic circulation and location of the source zones of deep-waters are essential to understand the role of oceans in the evolution of the climate during the Cretaceous, yet they remain unclear for this period. The neodymium (Nd) isotopes are used to track oceanic circulation and exchanges between water masses, in both past and modern oceans. The Nd isotope composition (εNd) in the ocean is related to the nature of the surrounding continental landmasses. The oceanic currents transport this isotopic signature, thus every oceanic basin acquires a singular εNd. Unequivocal interpretations of the Cretaceous seawater εNd va…

The Effects of Tamoxifen on Plasma Lipoprotein(a) Concentrations: Systematic Review and Meta-Analysis

2017

Introduction: Tamoxifen is a selective estrogen receptor modulator widely used in the treatment of breast cancer. Tamoxifen therapy is associated with reduced circulating low-density lipoprotein cholesterol and increased triglycerides, but its effects on other lipids are less-well studied. Aims: We aimed to investigate the effect of tamoxifen on circulating concentrations of lipoprotein(a) (Lp(a)) through systematic review and meta-analysis of available randomized controlled trials (RCTs) and observational studies. Methods: This study was registered in the PROSPERO database (CRD42016036890). Scopus, Medline and EMBASE were searched from inception until 22nd March 2016 to identify studies in…

Heterogeneity of P2-Purinoceptors in Brain Circulation

1990

The existence of P2-purinoceptors in the cerebrovascular bed was examined by testing the effects of ATP and its stable analog, α,β-methylene-ATP, on CBF in the unanesthetized goat as well as on isometric tension in isolated goat middle cerebral artery. When injected directly into the cerebral circulation, ATP increased and α,β-methylene-ATP decreased CBF. Indomethacin did not modify either of these effects. The vasoconstrictor action of α,β-methylene-ATP was reduced by nicardipine. “In vitro,” both ATP and α,β-methylene-ATP contracted the cerebral arteries at resting tone, but the analog was more potent than ATP. Repeated application of α,β-methylene-ATP as well as indomethacin significant…

Le limitazioni al regime di circolazione e valorizzazione delle azioni e quote, profili civilistici

2022

Il presente contributo propone l'analisi di alcuni strumenti giuridici offerti dall’autonomia privata in ambito societario, in modo da permettere all’imprenditore – in tutte le ipotesi in cui quest’ultimo intenda determinare, prima della sua morte, la successione dell’azienda di famiglia – di pianificare in modo efficace il passaggio generazionale, avvantaggiando o sfavorendo, a seconda dei casi, il trasferimento delle partecipazioni societarie, con il proposito di disinnescare i rischi di disgregazione dell’unità dell’impresa e di conflitti tra i membri della famiglia. This contribution proposes the analysis of some legal instruments offered by private autonomy in the corporate sphere, in …

Acute electrocorticographic changes following localized cortical freezing in the cat. Preliminary report.

1968

Use of photoplethysmography to determine gastrointestinal perfusion pressure: an experimental canine model.

2002

<i>Objectives:</i> To develop an experimental model to assess the parietal perfusion pressure (PPP) of the digestive tract using photoplethysmography. <i>Materials and Methods:</i> Twenty-two mongrel dogs were used. Progressive external compression was applied to the intestinal wall and the PPP was assessed with photoplethysmography. The study group was divided into two groups. In group 1 PPP was measured at the levels of the stomach, duodenum, jejunum and transverse colon. In group 2 PPP was measured after temporary occlusion of the truncal and marginal circulation of the jejunum to provide further variables. <i>Results:</i> The PPP decreased significant…