Search results for "Reactive"
showing 10 items of 1469 documents
Characterization of micromixing in a Continuous Oscillatory Baffled Reactor
2018
International audience; Micromixing is the limiting step in the progress of fast reactions and fast crystallization processes. Micromixing performance of a Nitech© glass COBR has been characterized using the competing parallel iodide-iodate test reactions. Macromixing length was also qualitatively determined by visualization of a tracer. The results show that an increase in the amplitude to baffle space ratio and a decrease of oscillation frequency improves mixing performance.
Iron, oxidative stress, and redox signaling in the cardiovascular system.
2014
The redox state of the cell is predominantly dependent on an iron redox couple and is maintained within strict physiological limits. Iron is an essential metal for hemoglobin synthesis in erythrocytes, for oxidation-reduction reactions, and for cellular proliferation. The maintenance of stable iron concentrations requires the coordinated regulation of iron transport into plasma from dietary sources in the duodenum, from recycled senescent red cells in macrophages, and from storage in hepatocytes. The absorption of dietary iron, which is present in heme or nonheme form, is carried out by mature villus enterocytes of the duodenum and proximal jejunum. Multiple physiological processes are invo…
The Friedreich's Ataxia protein frataxin modulates DNA base excision repair in prokaryotes and mammals
2010
DNA-repair mechanisms enable cells to maintain their genetic information by protecting it from mutations that may cause malignant growth. Recent evidence suggests that specific DNA-repair enzymes contain ISCs (iron–sulfur clusters). The nuclearencoded protein frataxin is essential for the mitochondrial biosynthesis of ISCs. Frataxin deficiency causes a neurodegenerative disorder named Friedreich's ataxia in humans. Various types of cancer occurring at young age are associated with this disease, and hence with frataxin deficiency. Mice carrying a hepatocyte-specific disruption of the frataxin gene develop multiple liver tumours for unresolved reasons. In the present study, we show that frata…
Acute pancreatitis in children. An Italian multicentre study
2002
Abstract Aim . To evaluate the clinical, morphological and aetiological aspects of acute pancreatitis in children in Italy. Patients . The hospital records of 50 consecutive patients with acute pancreatitis observed in 5 Italian Pediatric Departments were reviewed. Results . A total of 25 males and 25 females (median age 10.5 years, range 2–17) were studied. Of these patients, 48 (96%) had abdominal pain. The pancreatitis was associated with biliary disease in 10 patients (20%); it was due to viral infection in 6 patients (12%), pancreatic duct abnormalities in 4 (8%), familial chronic pancreatitis in 3 (6%), trauma in 5 (10%) and other causes in 5 (10%); the pancreatitis was of unknown ori…
An experimental and kinetic modeling study on the oxidation of 1,3-dioxolane
2021
International audience; The modern catalytic or enzymatic advances allow the production of novel biofuel. Among them, 1,3dioxolane can be produced from formaldehyde and ethylene glycol, both can be obtained from biomass. In this study, the oxidation of 1,3-dioxolane is studied at stoichiometric conditions. The ignition delay times of 1,3-dioxolane/O 2 /inert mixtures were measured in a shock tube and in a rapid compression machine at pressures of 20 to 40 bar and temperatures ranging from 630 to 1300 K. The pressure profiles recorded in the rapid compression machine show a first stage of ignition enlightening the influence of the low temperature chemistry of combustion. Furthermore, mole fr…
An experimental and modeling study of the oxidation of 3-pentanol at high pressure
2019
International audience; High pressure oxidation of 3-pentanol is investigated in a jet-stirred reactor and in a shock tube. Experiments in the reactor were carried out at 10 atm, between 730 and 1180 K, for equivalence ratios of 0.35, 0.5, 1, 2, 4 and 1000 ppm fuel, at a constant residence time of 0.7 s. Reactant, product and intermediate species mole fractions were recorded using Fourier transform infrared spectroscopy (FTIR) and gas chromatography (GC). Ignition delay times were measured for 3-pentanol/O2 mixtures in argon in a shock tube at 20 and 40 bar, in a temperature range of 1000–1470 K and for equivalence ratios of 0.5, 1 and 2. The fuel did not show any low-temperature reactivity…
Effect of boldine, secoboldine, and boldine methine on angiotensin II-induced neutrophil recruitment in vivo.
2005
AbstractAngiotensin-II (Ang-II) has inflammatory activity and is involved in different diseases associated with the cardiovascular system. This study has evaluated the effect of boldine (B), and two phenanthrene alkaloids semisynthesized by us, secoboldine (SB) and boldine methine (BM), on Ang-II-induced neutrophil recruitment. Intraperitoneal administration of 1 nM Ang-II induced significant neutrophil accumulation, which was maximal at 4–8 h. BM inhibited neutrophil infiltration into the peritoneal cavity at 4 h and 8 h by 73% and 77%, respectively, SB at 8 h by 55%, and B had no effect on this response. Although BM inhibited the release of cytokine-inducible neutrophil chemoattractant/ke…
A Combined Experimental and Theoretical Approach to the Photogeneration of 5,6-Dihydropyrimidin-5-yl Radicals in Nonaqueous Media
2016
The chemical fate of radical intermediates is relevant to understand the biological effects of radiation and to explain formation of DNA lesions. A direct approach to selectively generate the putative reactive intermediates is based on the irradiation of photolabile precursors. But, to date, radical formation and reactivity have only been studied in aqueous media, which do not completely mimic the micro environment provided by the DNA structure and its complexes with proteins. Thus, it is also important to evaluate the photogeneration of nucleoside-based radicals in nonaqueous media. The attention here is focused on the independent generation of 5,6-dihydropyrimidin-5-yl radicals in organic…
Biochemical biomarkers alterations in Coronavirus Disease 2019 (COVID-19)
2020
Abstract Coronavirus Disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a respiratory disease, which can evolve into multi-organ failure (MOF), leading to death. Several biochemical alterations have been described in COVID-19 patients. To date, many biomarkers reflecting the main pathophysiological characteristics of the disease have been identified and associated with the risk of developing severe disease. Lymphopenia represents the hallmark of the disease, and it can be detected since the early stage of infection. Increased levels of several inflammatory biomarkers, including c-reactive protein, have been found in COVID-19 patients and associ…
Essential oil of Cyphostemma juttae (Vitaceae): Chemical composition and antitumor mechanism in triple negative breast cancer cells
2019
The genus Cyphostemma (Planch.) Alston (Vitaceae) includes about 150 species distrib- uted in eastern and southern Africa and Madagascar. Some species are used in traditional medicine and their biological activities, including antiproliferative effects against cancer cell lines, have been demonstrated. To date no investigations on Cyphostemma essential oils have been carried out. Essential oils, which play important roles in plant defenses have been demonstrated to be active in the treatment of several human diseases and to enhance bioavability of other drugs. The aim of this paper was to identify the chemical composition of the essential oil of the leaves of Cyphostemma juttae (Dinter &…