Search results for "DIALYSIS"
showing 10 items of 528 documents
Neutralization of acid and base solutions by Reverse Electrodialysis with Bipolar Membranes: a sustainable way to recover energy
2020
The large amount of acidic wastewaters produced in various industrial processes can have a large economic and environmental impact. Companies producing waste acid solutions have to send them to specific sites for the neutralization with alkaline solutions. However, efforts have been devoted so far to promote the acid recovery or its reuse. In the perspective of a more circular manufacturing approach, the present work proposes for the first time the use of the novel Bipolar Membrane Reverse Electrodialysis technology as a viable on-site way to convert the chemical energy associated to the pH gradient of waste acid/base solutions into electrical energy. Bipolar Membrane Reverse Electrodialysi…
Structure of calcium and zinc pectinate films investigated by FTIR spectroscopy
2010
International audience; Calcium and zinc pectinate gels were prepared using a method which allowed calcium or zinc to diffuse from the cross-linking solution through a dialysis membrane to form a gel with amidated low-methoxyl pectin. The gel thus obtained was then dried, and the film structure was studied using FTIR spectroscopy as a function of the cation content (0%, 5%, 10%, and 15% w/v). Important consideration was given to the three functional groups (amide, carboxyl ester, and carboxylate groups) present in the pectin. When the zinc content was increased, the three wavenumber values corresponding to these three functional groups did not change significantly, while for calcium pectina…
Bioavailability of calcium from milk-based formulas and fruit juices containing milk and cereals estimated by in vitro methods (solubility, dialyzabi…
2005
An adequate calcium intake during the first years of life is needed for normal growth and development and to prevent rickets. The bioavailability of calcium from infant foods (milk-based formulas and fruit juices containing milk and cereals, FMC), the dietary sources of calcium in these stages of life, has been estimated on the basis of simulated gastrointestinal digestion and calcium solubility and dialyzability values and on the efficiency of transport and uptake by Caco-2 cells. The ranking of samples according to calcium bioavailability depends on the use of solubility or dialyzability as criterion. On the basis of the former, the highest value corresponded to adapted formulas and the l…
Vitom® 3D in arterio-venous fistulas: Single centre preliminary surgical experience
2021
Background: Arteriovenous fistula (AVF) is the vascular access of choice for hemodialysis patients. A correct microsurgical vascular anastomoses is essential to the optimal care of patients. Loupes can help surgeons perform such procedures, but often cause neck or back pain and fatigue. Aim: This study aimed to evaluate whether a video telescopic operating microscope (VITOM®; Karl Storz Endoscopy GmbH, Tuttlingen, Germany) could be used as a substitute for loupes to create microsurgical vascular anastomoses. Methods: We evaluated microsurgical anastomoses with VITOM® in 10 patients (6 male, 4 female) from January 2019 to December 2019. The created anastomoses were 7 side-to-side, 2 side-to-…
Imūnā atbildes reakcija uz vakcināciju pret vīrushepatītu B hemodialīzes pacientiem
2018
Pamatojums: Hemodialīzes (HD) pacientiem ir paaugstināts ar asinīm pārnesamām infekciju risks, piemēram, vīrushepatīta B infekcija (HBV). Pacientiem ar terminālu nieru mazspēju bieži ir imūnsistēmas nomākums, kas rezultējās ar nepietiekamu imūnās atbildes reakciju pret HBV vakcināciju. Adekvāta imunoloģiska atbilde it tad, ja anti-HBs-antivielu titrs >10 mSV/ml. Lai gan atbildes reakcija vispārējā populācijā ir aptuveni 95%, HD pacientiem tā ir robežās no 50-80%. Mērķis: noteikt HBV infekcijas izplatību, identificēt imūno atbildes reakciju HD pacientiem uz HBV vakcināciju un izvērtēt tās ietekmējošus klīniskus un laboratoriskus faktorus. Materiāli un metodes: Tika analizēta HBV izplatība HD…
Nitric oxide metabolites (nitrite and nitrate) in several clinical condition.
2013
We determined the concentration of nitric oxide metabolites (NO2-+NO3-), expressed as NOx, in several clinical conditions. Regarding this, we have examined 25 subjects with arterial hypertension, 41 subjects with chronic kidney disease in conservative treatment, 106 subjects with metabolic syndrome subdivided according to the presence (n = 43) or not (n = 63) of diabetes mellitus, 48 subjects with obstructive sleep apnea syndrome (OSAS), 14 women with systemic sclerosis complicated with Raynaud's phenomenon, 42 dialyzed subjects and 105 young subjects with acute myocardial infarction (AMI). In subjects with arterial hypertension, chronic kidney disease, metabolic syndrome, systemic sclerosi…
Pressure-Induced Deformation of Pillar-Type Profiled Membranes and Its Effects on Flow and Mass Transfer
2019
In electro-membrane processes, a pressure difference may arise between solutions flowing in alternate channels. This transmembrane pressure (TMP) causes a deformation of the membranes and of the fluid compartments. This, in turn, affects pressure losses and mass transfer rates with respect to undeformed conditions and may result in uneven flow rate and mass flux distributions. These phenomena were analyzed here for round pillar-type profiled membranes by integrated mechanical and fluid dynamics simulations. The analysis involved three steps: (1) A conservatively large value of TMP was imposed, and mechanical simulations were performed to identify the geometry with the minimum pillar density…
A hierarchical model for novel schemes of electrodialysis desalination
2019
Abstract A new hierarchical model for the electrodialysis (ED) process is presented. The model has been implemented into gPROMs Modelbuilder (PSE), allowing the development of a distributed-parameters simulation tool that combines the effectiveness of a semi-empirical modelling approach to the flexibility of a layered arrangement of modelling scales. Thanks to its structure, the tool makes possible the simulation of many different and complex layouts, requiring only membrane properties as input parameters (e.g. membrane resistance or salt and water permeability). The model has been validated against original experimental data obtained from a lab scale ED test rig. Simulation results concern…
Optimisation analysis of Reverse Electrodialysis systems for power production from concentrated brines
2016
Reverse Electrodialysis (RED) is rapidly growing as technology to produce electric energy by mixing saline solutions with different salinity. Recent developments have shown promising results on real site installations, demonstrating the feasibility of the RED process on the pilot scale. Therefore, further modelling efforts are now needed to optimise the technology, in order to enhance the performance. In this work, an optimisation study for the RED process is presented, taking into account saline waters and concentrated brine as feed streams. The model, which is developed within GAMS environment, predicts the optimal set of process variables that maximise the process yield, as well as the g…
Green Synthesis of Vanillin: Pervaporation and Dialysis for Process Intensification in a Membrane Reactor.
2019
In the present work, two different membrane processes (pervaporation and dialysis) are compared in view of their utilization in a membrane reactor, where vanillin, which is probably the most important aroma of the food industry, is synthesized in a green and sustainable way. The utilized precursor (ferulic acid, which is possibly a natural product from agricultural wastes) is partially oxidized (photocatalytically or biologically) and the product is continuously recovered from the reacting solution by the membrane process to avoid its degradation. It is observed that pervaporation is much more selective towards vanillin than dialysis, but the permeate flux of dialysis is much higher. Furthe…