Search results for "DIALYSIS"

Reverse electrodialysis heat engine (REDHE)

2022

Abstract Reverse electrodialysis (RED) is a membrane technology for the production of electricity via the “controlled mixing” of solutions at different salt concentrations, i.e., a diluted solution and a concentrated solution. The presence of ion-exchange membranes (IEMs) allows the production of renewable energy by converting the salinity gradient, which would be dissipated during a spontaneous (i.e., uncontrolled) mixing process, into an ionic current and, in a second step, into electricity at the electrodes. RED is the inverse process of the well-known electrodialysis process for salty water desalination, in which an electric field is applied at the electrodes and ionic currents are gene…

Bioaccessibility of minerals in school meals: Comparison between dialysis and solubility methods

2005

Abstract Determinations have been made of content and bioaccessibility of Ca, Fe, Zn and Cu in 13 dishes collected from a catering service delivering to a school. Bioaccessibility was estimated by measuring the soluble or dialyzable mineral fraction resulting from in vitro gastrointestinal digestion of the meal. The analyzed dishes had mineral contents (μg/g) in the following ranges: Ca (74.1–913), Fe (2.8–17.9), Zn (2.8–13.1), Cu (0.28–1.90). Mineral solubility and dialysis percentages were as follows: Ca (1.7–96.2; 0.75–61.3), Fe (16.0–97.8; 0.23–19.0), Zn (22.6–93; 5.78–31.45), Cu (35.7–92.3; 0.66–25.0). The highest bioaccessible Ca content corresponded to fish-based dishes, while vegeta…

A Dialysis Photocatalytic Reactor for the Green Production of Vanillin

2020

In the present work, dialysis was used to recover vanillin while being produced by partial photocatalytic oxidation of ferulic acid in an aqueous solution at ambient temperature. The relatively high value of the permeate flux through a dense polyether-block amide membrane allowed continuously extracting vanillin from the reacting solution, thus avoiding its successive oxidation. The rate of vanillin formation was improved, compared to other reactor configurations, because intermediate compounds permeated from the reacting solution and did not hinder the reaction, while ferulic acid permeated in the opposite direction to partially replenish the reactor with the substrate. The photocatalytic …

1997

A bipolar membrane (BM) is a layered structure composed of one cation and one anion ion-exchange layers joined together in series. Polymer BMs offer promising applications for many industrial processes (e. g., the use of bipolar electrodialysis for environmentally clean technologies and the treatment of salt-water effluents) because of their unique electrochemical properties. The most important of these properties is the electric field enhanced (EFE) water dissociation which arises when an electric current is forced through the membrane. This phenomenon occurs at the bipolar junction of the BM, and its coupling with ion transport, though still poorly understood, is the basis of most of the …

Role of serotonin in central dopamine dysfunction

2010

The interaction between serotonin (5-HT) and dopamine (DA)-containing neurons in the brain is a research topic that has raised the interest of many scientists working in the field of neuroscience since the first demonstration of the presence of monoamine-containing neurons in the mid 1960. The bulk of neuroanatomical data available clearly indicate that DA-containing neurons in the brain receive a prominent innervation from serotonin (5-hydroxytryptamine, 5-HT) originating in the raphe nuclei of the brainstem. Compelling electrophysiological and neurochemical data show that 5-HT can exert complex effects on the activity of midbrain DA neurons mediated by its various receptor subtypes. The m…

Special applications of reverse electrodialysis

2016

Reverse electrodialysis (RED) is a process for direct electricity production from salinity gradients, based on the use of suitable exchange membranes. To develop the RED process on an applicative scale and to add value to the overall process, a key role is entrusted to the selection of electrodic system, redox species, and electrode materials. In particular, it was shown that a proper selection of redox processes allows the use of a RED cell for the wastewater treatment of organic and inorganic pollutants resistant to conventional biological methods and for the synthesis of chemicals without energy supply. The utilization of microbial reverse electrodialysis cells was also proposed to incre…

Molecular epidemiology of a hepatitis C virus outbreak in a hemodialysis unit.

2005

ABSTRACT We analyzed a hepatitis C virus (HCV) transmission case in the hemodialysis unit of a private clinic by sequencing two genome regions of virus isolates from a number of patients attending this unit and some external controls. The analysis of 337 nucleotides (nt) in the NS5B region did not provide enough resolution to ascertain which patients were actually involved in the outbreak and the potential source. Nevertheless, this region allowed the exclusion of several patients as putative sources of the transmission case based on their genotypes and phylogenetic relationships. On the other hand, the analysis of several 472-nt-long clone sequences per sample in a more rapidly evolving re…

Epidemiology and molecular investigation of hepatitis C infection following holiday haemodialysis

2012

Background: Hepatitis C virus infection (HCV) is not infrequent among haemodialysis patients. Most published reports suggest that patient-to-patient spread, either directly or indirectly, is the most common mode of transmission in renal units. Aim: To investigate the source of an outbreak, and the route of transmission, of acute HCV infection in two Scottish patients occurring within eight weeks of receiving haemodialysis in the same unit while on holiday in Majorca. Methods: This was an international epidemiological and molecular investigation of HCV infection among a cohort of haemodialysis patients from nine countries. Findings: No further HCV-positive infections were observed among resi…

COVID-19—Importance for Patients on the Waiting List and after Kidney Transplantation—A Single Center Evaluation in 2020–2021

2021

(1) Background: Dialysis patients and recipients of a kidney allograft are at high risk for infection with SARS-CoV-2. It has been shown that the development of potent neutralizing humoral immunity against SARS CoV-2 leads to an increased probability of survival. However, the question of whether immunocompromised patients develop antibodies has not yet been sufficiently investigated; (2) Methods: SARS-CoV-2 antibodies were examined in hemodialysis patients on the waiting list for kidney transplantation as well as patients after kidney transplantation. Patients were interviewed about symptoms and comorbidities, BMI, and smoking history; (3) Results: SARS-CoV-2 antibodies were found in 16 out…

KA-672 inhibits rat brain acetylcholinesterase in vitro but not in vivo.

1999

Abstract KA-672, a lipophilic benzopyranone derivative which is currently under development as a cognitive enhancer and antidementia drug, has previously been shown to have facilitatory effects on learning and memory in rats at doses of 0.1–1 mg/kg. We now report that KA-672 inhibited the activity of acetylcholinesterase (AChE), measured in vitro in rat brain cortical homogenate, with an IC 50 value of 0.36 μ M indicating that KA-672 may improve cognitive functions as a consequence of AChE inhibition. However, when we employed the microdialysis procedure to monitor acetylcholine (ACh) release from rat hippocampus, no effect of KA-672 (0.1–10 mg/kg) was found, indicating a lack of inhibition…