Search results for "Osmosi"
showing 10 items of 84 documents
Optical experiments on a crystallizing hard-sphere–polymer mixture at coexistence
2010
We report on the crystallization kinetics in an entropically attractive colloidal system using a combination of time resolved scattering methods and microscopy. Hard sphere particles are polystyrene microgels swollen in a good solvent (radius a=380nm, starting volume fraction 0.534) with the short ranged attractions induced by the presence of short polymer chains (radius of gyration rg = 3nm, starting volume fraction 0.0224). After crystallization, stacking faulted face centred cubic crystals coexist with about 5% of melt remaining in the grain boundaries. From the Bragg scattering signal we infer the amount of crystalline material, the average crystallite size and the number density of cry…
Optimal design of cogeneration plants for seawater desalination
2004
Multi-stage flash (MSF) and reverse osmosis (RO) are the most common techniques for seawater desalination. A significant difference between these methodologies consists of their different energy requirements, i.e., thermal energy for MSF and mechanical energy for RO plants. The presence of both desalination systems (MSF and RO) appears to be suitable for cogeneration plants. The reject heat from the power cycle can feed an MSF section, while some power feeds the RO section and the MSF auxiliary equipment; the rest is sold to the grid. A criterion for the optimal design of such tri-functional cogeneration plants is proposed, based on exergo-economics and on profit maximization. In particular…
Diversità nei luoghi: condizioni da esplorare
2012
Contributo scientifico sulla diversità dei luoghi in relazione alla definizione di “Progetto” quale connotazione imprescindibile della sua natura disciplinare nell’ambito della ricerca Turismo Relazionale Integrato, per il progetto regionale e internazionale MOTRIS II. Curato dal Collegio Universitario ARCES con il supporto scientifico del Centro Ricerche nuovo Umanesimo Edoardo Caracciolo (CRUEC).
Cytotoxic Action of Serratia marcescens Hemolysin on Human Epithelial Cells
1999
ABSTRACT Incubation of human epithelial cells with nanomolar concentrations of chromatographically purified Serratia marcescens hemolysin (ShlA) caused irreversible vacuolation and subsequent lysis of the cells. Vacuolation differed from vacuole formation by Helicobacter pylori VacA. Sublytic doses of ShlA led to a reversible depletion of intracellular ATP. Restoration to the initial ATP level was presumably due to the repair of the toxin damage and was inhibited by cycloheximide. Pores formed in epithelial cells and fibroblasts without disruption of the plasma membrane, and the pores appeared to be considerably smaller than those observed in artificial lipid membranes and in erythrocytes a…
Experimental investigation and modeling of diffusion dialysis for HCl recovery from waste pickling solution
2019
Abstract Hydrochloric acid recovery from pickling solutions was studied by employing a batch diffusion dialysis (DD) laboratory test-rig equipped with Fumasep membranes. The effect of main operating parameters such as HCl concentration (0.1–3 M) and the presence of Fe2+ (up to 150 g/l) was investigated to simulate the system operation with real industrial streams. The variation of HCl, Fe2+ and water flux was identified. When only HCl is present, a recovery efficiency of 100% was reached. In the presence of FeCl2, higher acid recovery efficiencies, up to 150%, were observed due to the so-called “salt effect”, which promotes the passage of acid even against its concentration gradient. A 7% l…
Desiccation and osmotic stress increase the abundance of mRNA of the tonoplast aquaporin BobTIP26-1 in cauliflower cells.
1999
Changes in vacuolar structure and the expression at the RNA level of a tonoplast aquaporin (BobTIP26-1) were examined in cauliflower (Brassicaoleracea L. var. botrytis) under water-stress conditions. Gradual drying out of slices of cauliflower floret tissue caused its collapse, with a shrinkage in tissue and cell volumes and an apparent vesiculation of the central vacuole, whereas osmotic stress resulted in plasmolysis with a collapse of the cytoplasm and the central vacuole within. Osmotic stress caused a rapid and substantial increase in BobTIP26 mRNA in slices of floret tissue. Exposure of tissue slices to a regime of desiccation showed a slower but equally large rise in BobTIP26 mRNA fo…
On the nature of the forces controlling selectivity in the high performance capillary electrochromatographic separation of peptides
2003
In this minireview, the nature of the forces controlling selectivity in the high performance capillary electrochromatographic (HP-CEC) separation of peptides has been examined. For uncharged and charged peptides, a synergistic interplay occurs in HP-CEC systems between adsorptive/partitioning events and electrokinetically driven motion. Moreover, at high field strengths, both bulk electrophoretic migration and surface electrodiffusion occur. Thus, the migration behavior of peptides in different HP-CEC systems can be rationalized in terms of the combined consequences of these various processes. Moreover, in HP-CEC, the buffer electrolyte interacts with both the peptide analytes and the sorbe…
Iontophoretic Transdermal Delivery of Sumatriptan: Effect of Current Density and Ionic Strength
2005
ABSTRACT: Iontophoretic transdermal delivery of sumatriptan was investigated in vitro . Among the conditions tested, 0.25 mA/cm 2 and low ionic strength (NaCl 25 mM) was the best experimental condition to increase its transport across the skin. The flux increased 385-fold respective to passive diffusion, thus resulting in a transdermal flux of sumatriptan of 1273 ± 83 nmol/cm 2 h. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association
Nonsense-mediated mRNA decay controls the changes in yeast ribosomal protein pre-mRNAs levels upon osmotic stress.
2013
The expression of ribosomal protein (RP) genes requires a substantial part of cellular transcription, processing and translation resources. Thus, the RP expression must be tightly regulated in response to conditions that compromise cell survival. In Saccharomyces cerevisiae cells, regulation of the RP gene expression at the transcriptional, mature mRNA stability and translational levels during the response to osmotic stress has been reported. Reprogramming global protein synthesis upon osmotic shock includes the movement of ribosomes from RP transcripts to stress-induced mRNAs. Using tiling arrays, we show that osmotic stress yields a drop in the levels of RP pre-mRNAs in S. cerevisiae cell…
Characterization of pressure retarded osmosis lab-scale systems
2016
Power generation from salinity gradient is a viable alternative to produce energy from renewable sources. Pressure Retarded Osmosis (PRO) is one of the technologies proposed so far for the exploitation of such energy source. In the present preliminary work, two different geometry modules were tested under atmospheric pressure (i.e. forward osmosis or depressurized-PRO conditions). The first one is a conventional planar geometry cell. The second is a customized cylindrical membrane module, able to mechanically support the osmotic membrane along with the spacers. The latter, thanks to its design, allows membranes and spacers to be easily changed for testing purposes. A novel simplified proced…