Glass Wool Filter Research Articles

Interferences in the spectrophotometric S-diphenylcarbazide determination of environmental hexavalent chromium in a chromium and zinc plating plant.

A study on the determination of environmental hexavalent chromium [Cr(VI)] was carried out in a chromium and zinc plating plant. The atmospheric particulate was collected both on glass wool filters and with an electrostatic sampler; Cr(VI) was determined by the S-diphenylcarbazide method. The filtered and electrostatically collected Cr(VI) was extracted with both 1.4% sulfuric acid and 7% sodium carbonate. Strong interference was observed when extraction was carried out with the acid medium. Alkaline extraction permits 95 +/- 6 (+/- SD)% recovery of the total chromium and has been shown to be suitable in releasing Cr(VI). The analyses of the alkaline samples were carried out with the standard addition method to compensate for a depressive interference of 26 +/- 8 (+/- SD)%. The absorbance decrease of the Cr-S-diphenylcarbazide complex is a time function, and it should be measured within a few minutes of the reagent addition.

Modification of the Friberg microagglutination tray technique for detection of sperm antibodies.

The Friberg microagglutination tray technique for the detection of sperm-agglutinating antibodies in the serum has several advantages over other techniques. Microquantities of a single-donor sperm specimen may be used for several tests and the agglutinates may be examined directly with an inverted lense microscope. However, in its original form, there were a few technical problems. The technique has been modified to eliminate the problems. The donor sperm is filtered through a glass wool filter. The procedure was adapted for Terasaki tissue culture plates. With these modifications the technique seems more practical for clinical usage.

Routine direct injection gas—liquid chromatographic procedure for the analysis of volatile halogenated anaesthetics in whole blood using a new external injection port

This communication describes the design and construction of a new external injection port for the direct gas—liquid chromatographic analysis of volatile compounds in whole blood. Aliquots (4–40 μl) of EDTA anti-coagulated blood containing the volatile compound and a weighed quantity of the internal standard, isobutanol, were injected into the disposable glass wool filter of the heated injection port. The volatiles released were led by means of the carrier gas stream directly onto the chromatographic column. Typical data are presented from chromatography performed with dual 6 ft. × 2 mm I.D. glass columns containing Chromosorb 101 programmed from 110–180° at 6°/min and the external injection port maintained at 180°. The method eliminated the problems usually associated with direct injection methods and permitted the accurate analysis of halothane, methoxy-flurane, diethyl ether and ethanol over the approximate range 1–100 mg%. Using this analytical procedure the distribution of halothane between the cells and plasma of human blood at 4° was found to be 2.0 ± 0.2.

Prevention of postischemic impairment of microvascular perfusion.

Two groups of conditioned male mongrel dogs, designated group 1 and group 2, were subjected to 35 minutes of cerebrospinal fluid compression ischemia followed by 30 minutes of recirculation. Animals in both groups were heparinized, but in addition, the blood of group 2 animals was circulated through three glass-wool filters over the course of 1 hour prior to induction of ischemia. Focal zones of impaired perfusion were prevented and general reflow was significantly enhanced in group 2 animals, whose blood had been filtered through glass-wool. Animals in group 1 had focal zones of impaired perfusion and relatively poor general postischemic reflow. A hypothesis concerning blood-damaged tissue interaction in zones of acute tissue damage is introduced.

Effect of conductivity on charge generation in hydrocarbon fuels flowing through fiber glass filters

The quantity of electrostatic charge generated when hydrocarbon fuels are passed over a phenol-formaldehyde resin-coated fiber glass filter is dependent upon the conductivity of the liquid and the flow velocity through the filter. As the conductivity of the liquid is increased, the charging tendency, as measured by the filter current, increases, passes through a maximum, and then decreases. At higher flow velocities, the position of the maximum in the filter current vs. conductivity curve was found to shift to a higher conductivity range. In most cases, the sign of the charge on the fuel was found to be dependent upon the nature of the surface of the filter material. Thus, when phenol-formaldehyde resin-coated fiber glass, nylon, dacron, and Kel-F filters were used, the sign of the streaming current was usually positive. When ordinary glass wool or fiber glass filters, from which the resin coating had been removed by baking, were used, the current was negative. By dividing the flow of fuel from a storage tank into two streams each containing different filter materials, one causing the fuel to acquire a positive charge and the other a negative charge, and by carefully controlling the flow through each filter, it was possible to deliver fuel to the receiving tank with virtually no net charge on it. The results suggest a possible method of reducing the charge level on fuel in a practical system by employing two types of filter elements in a filter separator unit, each producing charges of the opposite sign in the fuel. Another possibility would be to fabricate the filter element using alternate layers of filter materials which produce charges of opposite sign in the fuel. Although the latter method appears to be less effective, it may offer some advantages from a manufacturing standpoint.

Rapid flow, isolated renal perfusion

Rapid flow, isolated perfusion of the kidney has been extended from 5 minutes to several hours, and even to 22 hours in the case of in vitro perfusion. In accomplishing this it was found that the block that occurs 5 minutes after perfusion begins could be eliminated by prior filtration of the perfusate through a glass-wool filter. A second perfusion block occurred 20 to 40 minutes after the onset of perfusion. This block could be eliminated by the addition of a serotonin antagonist, UML-491, to the perfusate. The cause of the first block is most probably platelet aggregates. It is not established whether the second block is caused by further platelet aggregation or by the vasoconstrictor effects of serotonin. A marked decrease in circulating platelets occurred in 5 of the experiments during the first 10 minutes of perfusion, but subsequent changes were either minimal or absent. Kidneys that are perfused for 3 or 4 hours in situ function normally after contralateral nephrectomy. Subsequent examination, however, reveals focal areas of cortical scarring. Reimplantation of kidneys which have been perfused 8 hours has been unsuccessful because a severe clotting defect develops in the recipient dog which results in exsanguination. The kidneys, however, appear to be viable and capable of regaining function.

Rapid Modified Eriochrome Cyanine R Method for Determination of Aluminum in Water

This study developed a rapid, sensitive, accurate method for the determination of small amounts of aluminum in water. The method uses an eriochrome cyanine R dye that is a modification of Knight's method. The key factors in the modification are adjustment of the dye solutions and elimination of alkalinity, which, even in “trace” amounts, has a marked inhibitory effect. Other interferences are also eliminated, including iron and manganese with ascorbic acid, complex phosphates by boiling with acid, and fluoride, removed either by volatilization or by adding known concentrations of the ion to the aluminum solutions used in preparing calibration curves. Data are also presented to show that glass wool, absorbent cotton, and most filter papers remove nearly all the soluble aluminum from an aluminum solution. Only membrane filters can be used with confidence for this purpose. Finally, using the PSW modified method, it has been possible to demonstrate that aluminum concentrations of 0.05 mg/l or less can be expected in the filter effluent from a well‐operated water treatment plant.

ALTERATION OF BLOOD DURING ACUTE HYPOTENSION: EFFECT OF CONTINUOUS GLASS WOOL FILTRATION.

Acute hypotension was produced in heparinized and nonheparinized dogs by hemorrhage and by injections of histamine, and adhesiveness and aggregation of blood elements determined periodically by the screen filtration pressure method. This method measures the pressure required to force blood at a constant rate through a standardized screen with multiple square holes each 20 x 20 micra. In some cases the arterial blood was perfused through a glass wool filter in an extracorporeal system both before and during periods of hypotension. The results of these studies justify the following conclusions: 1. Increased adhesiveness and aggregation of platelets and other blood elements which occur during hypotension produced by hemorrhage or intravenous injections of histamine were indicated by an increase in the screen filtration pressure of blood. These changes were not prevented from developing, or significantly altered by heparinization of the animal. 2. The amount of blood which could be obtained during arterial hemorrhage was significantly increased by heparinization of the animal. 3. The adhesive and aggregated platelets and leucocytes, which formed during hypotension, were removed from the blood when it was perfused through a column of glass wool. This treatment was attended by a decrease in the screen filtration pressure of the blood to or below normal. 4. The increase in screen filtration pressure which occurred during hypotension was much less marked if the animals' blood had first been circulated through pyrex glass wool. 5. Filtration of blood through pyrex glass wool was also attended by a progressive decrease in the mean arterial blood pressure of the animal.

MICROBIOLOGICAL STUDIES OF AIR OVER SOME NONARCTIC REGIONS OF CANADA

Using aircraft, studies were carried out on the numbers of bacteria and fungi in the air and 10 separate flights were made during 1948 and 1949 covering territory between Goose Bay, Labrador, and Fairbanks, Alaska. Quantitative samples were taken on agar plates, and silicone coated slides in the McGill G.E. Sampler, as well as in glass wool filters and the results correlated with definite air masses. A comparison of methods showed that the McGill G.E. Sampler gives higher and more consistent results for the total viable count than the filters. Silicone coated slides give the total fungus count including nonviable spores and spores that will not grow on the agar plates.From various air masses and during different times of the year, there was considerable variation in the average number of bacteria and fungi found. The highest fungus count was 23.6 per cu. ft. and the lowest 0.01. There was less variation in the number of bacteria, the highest being 5.6 and the lowest 0.2 per cubic foot. The highest fungus counts were found in continental polar air during the summer months while for the bacteria the highest counts were found in Pacific polar air during the spring and fall. The bacteria and fungi isolated were all soil types.