Monitors flow radioactivity

Another method, which is routinely used for gradient determinations is flow dialysis [48]. In this method a compartment containing the membrane preparation and the radioactively labeled solute or indicator molecules is separated from a second compartment via a dialysis membrane. The solution in the second compartment is replaced with a constant rate and the radioactivity in the outflowing solution is monitored. The radioactivity monitored reflects the concentration of the radioactive probe in the external medium in the first compartment. Recently, an automatization of this technique has been described which considerably increases the... 

PGA extracts were analyzed by HPLG using described methods (6). Purine nucleosides and bases were separated with a reversed-phase column. Purine nucleotides were separated by anion-exchange HPLG. Simultaneous UV monitoring and radioactivity detection were performed with an on-line radioactivity flow detector. 

The vent air from the controlled area, amounting to about 200,000 mVh is continuously monitored for radioactive substances. To this end, bypass flows are extracted and passed through radioactivity monitoring lines. After radioactivity measurement, these air flows converge again and then are passed to the vent stack. 

The radiation monitors associated witii the steam generator blowdown system provide a means of recognising when the secondary side becomes radioactively contaminated, an indication of a steam generator tube mpture. The blowdown flow and the ion exchange waste stream (brine) flow are both continuously monitored for radioactivity. If such radioactivity is detected, the liquid radwaste system is aligned to process the blowdown and ion-exchange waste effluent. If radioactivity should exceed a preset level, the blowdown flow control valves and the isolation valves would automatically close. 

The supply air flow is automatically modulated to maintain a negative pressure in the areas served with respect to the outdoors and to surrounding areas which do not have their exhausts monitored for radioactivity. Differential pressure controllers, with sensors in the general health physics area and sensors mounted outdoors (shielded from wind effects), modulate the automatic inlet vanes of the supply fan to maintain area negative pressure. In addition, a separate differential pressure controller with a sensor in the hot machine shop modulates a damper in the supply air duct to the hot machine shop to maintain a negative pressure in the shop with respect to outdoors and to surrounding areas which do not have their exhausts monitored for radioactivity. 

Gas ionization detectors are widely used in radiochemistry and X-ray spectrometry. They are simple and robust in construction and may be employed as static or flow detectors. Flow studies have received attention in the interfacing of radioactive detectors with gas chromatographs. A radio-gas chromatograph (Figure 10.9) uses a gas flow proportional counter to monitor the effluent from the gas chromatography column. To achieve... 

Monetary system, bimetallic, 22 647—648 Money flows, annual, 9 537-540 Monitored retrievable storage (MRS) facility, for spent radioactive fuel, 25 855... 

Nuclear A test of the structure, blood flow, and function of the kidneys. The doctor injects a mildly radioactive solution into an arm vein and uses x-rays to monitor its progress through the kidneys. [NIH]... 

A batch of radioactive material is dumped into the Columbia River at Hanford, Washington. At Bonneville Dam, about 400 km downstream the flowing waters (6000 m /s) are monitored for a particular radioisotope ty2 > 10 yr) and the data of Fig. P11.5 are obtained. 

Following its emergence from the other end of the column, the eluent flows through the detector. Detectors operate on various principles. For example, some monitor the ultraviolet, visible, or fluorometric properties of molecules others monitor radioactivity and still others monitor differences in oxidation-reduction potential and refractive index. These detectors are listed in Table 2.1 together with some examples of the specific reactions with which they have been used. 

Figure 9.57 Separation of [5-l4C]a-ketoglutarate (A) and [4-,4C]aminolevulinic acid (B) by HPLC on a Hypersil column with methanol-aqueous PIC B-7 (50 150, v/v) as the mobile phase at a flow rate of 1 mL/min. (a) Mixture in distilled water. (b) Mixture in presence of salts recovered from a freeze-dried incubation mixture. Solid lines, spectrophotometric monitoring at 278 nm and 0.05 AUFS dashed lines, radioactive distribution (0.5 mL fractions counted). (From Tikerpae et al., 1981.)...

Radiolabeled UDP-glucose and sucrose-P were separated on a Selectispher-10 boronate column (5 mm x 250 mm). The mobile phase was 0.12 M sodium phosphate (pH 7.6) delivered at a rate of 1 mL/min. The column eluent was monitored for absorbance at 262 nm, and for radioactivity by a radioactive flow-through detector. 

Reaction mixtures are chromatographed on a PolyHydroxyethyl Aspartam-ide column (4.6 mm X 100 mm) from Poly LC (Columbia, MD). Inorganic phosphate is not adsorbed to the column under the initial conditions (40 mM triethylamine-phosphoric acid, pH 2.8), while elution of ATP requires 800 mM triethylamine-phosphoric acid (pH 2.8). Initial conditions are maintained for 16 minutes and total run time was 30 minutes including reequilibration. Column effluent was monitored by a flow-through radioactivity monitor. 

---