Dialyser unit

For consistency, clearance here is expressed in cm /s although the more common clinical units, and those used later in this chapter, are ml,/min. Combination and rearrangement of equations 6—8 allows clearance to be estimated from mass-transfer coefficient and vice versa the conditions of countercurrent flow with no dialysate recycling are shown below. 

Figure 3.12 — Interfacing of a fermenter to an FI system. The fermenter medium is continuously recycled by a pump to the filter unit, from which the filtrate is guided to a small reservoir (500 /xL). The sample solution is aspirated through a dialyser, the acceptor stream of which is fed to the injector of the FIA system. The analyte content is assayed amperometrically by using the glucose sensor incorporating the enzyme-containing chemically modified electrode. (Reproduced from [86] with permission of Elsevier Science Publishers).

Figure 29.14 demonshates a schematic of connection of HSGD-containing unit to a hemodialysis machine. Here hydrodynamic stability of the column with uncoated dehganding sorbent is achieved via local citrate injection followed by removal of excessive citrate, and concentration of Ca is restored in the connected dialyser. 

Additional checks were made using a dialysis procedure in which zeolite samples which had been isotopically equilibrated with a 22Na O.OlAf NaCl solution were dialyzed against distilled water. After repeated washings, the sodium loss from NaX reached a steady value of 2.8 ( 0.1) ions/ unit cell at a zeolite content of 0.44 gram/liter, i.e. a value which is nearly identical to the data in Table I for a 10 NaCl concentration. Under similar conditions, the sodium loss from NaY is much less and corresponds to 1.5 ( 0.1) ions/unit cell. These results were confirmed by electrical conductivity measurements on the respective dialysates the conductivity for NaX is about twice as large (7.5 X 10 6 mhos/cm) as for NaY (3.9 X 10 6 mhos/cm). 

The capacity for toxin removal of an hemodialyzer is expressed by the dialysance or the clearance which have the same unit as a flow rate. The dialysance D is defined, for each toxin as... 

In the Liver Dialysis Unit (HemoCleanse Technologies, Lafayette, USA), the adsorbents (powdered activated charcoal and cation-exchangers) are located in the dialysate-moving phase [31]. Dialysate content is adjusted so as to prevent... 

Hot dialysis In hot dialysis, a temperature of 65-90°C increases the rate of dialysis by about three times. Heating is done by placing an electrical heating unit in the dialyser. All hydrophobic sols cannot withstand the high temperature and the membranes may give off undrained colloidal impurities. 

In Curacao, the major island of the Netherlands Antilles with a population of 130,000 inhabitants, distilled seawater from the water plant was used without further purification for hemodialysis for several decades. Unfortunately, two months before the planned installation of a water treatment system including a reversed osmosis (RO) in the dialysis center Diatel, a new distribution pipe supplying water to a dialysis center on the island was installed in 1996. To protect it from corrosion, this pipe was lined on the inside with a cement mortar. Because of the aggressiveness of the distilled water, calcium and Al leached from the cement mortar into the water used to prepare dialysate. At the time of replacement of the new conduit pipe, 29 patients were dialyzed in the dialysis unit. Patients were dialyzed three times per week during 3.5 to 4.5 hours using hollow fiber kidneys (Fresenius, F6 and F8). Untreated tap... 

A unique set of circumstances was responsible for symptoms resembling hard water syndrome [64] followed by an epidemic of acute Al encephalopathy in a dialysis unit (Diatel) on the island of Curasao. A tragic coincidence is that the intoxication happened about two months before the planned installation of a water treatment system with deionization and reverse osmosis (RO). Traditionally, municipal water had been used for more than two decades without extended purification for the production of dialysate. The pure... 

Haemodialysis usually takes about 4-7 h and the dialysing solutions are changed periodically. Ask in your hospital about the exact procedures used for dialysis, usually organized by the renal unit. You also might ask what stringent safety and health risk precautions the workers must undertake when working in the unit. 

Materials. Starting materials were obtained as follows Fresh whole blood was obtained as a "short unit" (Irwin Memorial Blood Bank, San Francisco, CA) hemoglobin was prepared from washed red blood cells by cell lysis using three volumes of sterile H2O at 4°C. The cell debris was removed by centrifugation (12 000 g, 15 min), and residual serum proteins were precipitated in 20% (v/v) ammonium sulfate. The hemoglobin-containing supernatant was dialysed against 0.01 M Bis-Tris (pH 7.0) [8—14C]... 

For simultaneous determinations and /or speciation, different separation/ concentration steps can be implemented in the same manifold, as in, e.g., the determination of nitrogen, phosphorus and potassium in fertilisers [314]. The sample was inserted and passed successively through a dialysis unit and a gas diffusion unit to a flow cell for the spectrophotometric determination of phosphate. The dialysed potassium ions and the diffused gaseous ammonia were collected in specific streams and determined by flame photometry and potentiometry, respectively. 

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