31 research outputs found
The chemistry of sulfur and nitrogen species in a fog system A multiphase approach
Concentration and phase distribution of sulfur and nitrogen species during a particular fog episode in the Po Valley are experimentally described in this paper. Chemical measurements were carried out simultaneously at different heights within the fog layer, up to 50 m. Microphysical and meteorological parameters necessary for the description of the fog multiphase system were also concurrently measured as a function of height. The fog cycle (formation, evolution, dissipation) is described in terms of the total acidity of a unit volume of air containing gas species, interstitial aerosol particles and fog droplets. The fog system was not closed and input of acidic and basic components was observed during fog evolution. The driving force which determines the acidity of the fog multiphase atmospheric system was found to be the presence of NH 3 and its partitioning among the different phases. A strong decrease of fog water pH (from 5.6 down to 2.8) was observed during fog evolution and was attributed to a HNO 3 input to the system. These acidic and basic inputs are described in terms of a titration/back-titration process of the fog system. The SO 2 oxidation process in fog water was found to be of minor importance in determining the SO 4 = concentration within the fog system, due to both low SO 2 concentration and limited oxidant availability during the experiment. DOI: 10.1034/j.1600-0889.1992.t01-4-00005.
Extraction of valuable compounds from Arthrospira platensis using pulsed electric field treatment
Pulsed electric field (PEF) treatment was evaluated for phycocyanin and proteins extraction from Arthrospira platensis (Spirulina platensis). PEF extractions were performed using different specific energies (28, 56 and 122 J·ml−1 of suspension) and the results were compared to the extraction with bead milling. At highest PEF- treatment energies a damage of the cell morphology could be observed and the highest yields (up to 85.2 ± 5.7 mg·g−1 and 48.4 ± 4.4 g·100 g−1 of phycocyanins and proteins, respectively) could be obtained at 122 and 56 J·ml−1. The yields increased with incubation time after PEF-treatment. The antioxidant capacity of the extracts obtained after PEF-treatment was higher than of those obtained after bead milling. PEF treatment is a promising technology to obtain blue-green antioxidant extracts from A. platensis in an environmental friendly process
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Contribution of mGluR5 to hippocampal pathophysiology in a mouse model of human chromosome 16p11.2 microdeletion
Human chromosome 16p11.2 microdeletion is the most common gene copy number variation in autism, but the synaptic pathophysiology caused by this mutation is largely unknown. Here we show using a mouse with the same genetic deficiency that metabotropic glutamate receptor 5-(mGluR5-) dependent synaptic plasticity and protein synthesis is altered in the hippocampus, and that hippocampus-dependent memory is impaired. Remarkably, chronic treatment with a negative allosteric modulator of mGluR5 reverses the cognitive deficit
Chronic Pharmacological mGlu5 Inhibition Corrects Fragile X in Adult Mice
Fragile X syndrome (FXS) is the most common form of inherited intellectual disability. Previous studies have implicated mGlu5 in the pathogenesis of the disease, but a crucial unanswered question is whether pharmacological mGlu5 inhibition is able to reverse an already established FXS phenotype in mammals. Here we have used the novel, potent, and selective mGlu5 inhibitor CTEP to address this issue in the Fmr1 knockout mouse. Acute CTEP treatment corrects elevated hippocampal long-term depression, protein synthesis, and audiogenic seizures. Chronic treatment that inhibits mGlu5 within a receptor occupancy range of 81% ± 4% rescues cognitive deficits, auditory hypersensitivity, aberrant dendritic spine density, overactive ERK and mTOR signaling, and partially corrects macroorchidism. This study shows that a comprehensive phenotype correction in FXS is possible with pharmacological intervention starting in young adulthood, after development of the phenotype. It is of great interest how these findings may translate into ongoing clinical research testing mGlu5 inhibitors in FXS patients.Eunice Kennedy Shriver National Institute of Child Health and Human Development (U.S.)Autism Science Foundation (Fellowship
Rational design, synthesis, and structure-activity relationship of benzoxazolones: new potent mglu5 receptor antagonists based on the fenobam structure
A novel class of potent and stable mGlu5 receptor antagonists was developed by combining information from a high-throughput screening campaign with the structure of the known anxiolytic fenobam. Representative compounds from this class show favorable pharmacokinetic properties and are active in an in vivo model of anxiety