scholarly journals Studying the Dependence of the Toxic Effect on the Time of the Toxicant's Contact with the Algae Culture

2019 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Toxic Effect ◽  
Contact Time ◽  
Photosynthetic Activity ◽  
Toxic Substances ◽  
Toxicity Bioassay ◽  
Before And After ◽  
Direct Dependency ◽  
Test Objects

Relevance. The intensity of photosynthesis is the most common toxicity test when using algae as test objects. All methods for determining photosynthesis are based on measuring the rate of oxygen evolution or absorption of carbon dioxide in an incubation medium before and after a certain exposure of algae culture to light. Purpose. Determination of threshold concentrations of toxic substances for this method and study of the dependence of the type of dose-value of the toxic effect. Results. Toxicity bioassay by evaluating the photosynthetic activity of algae is possible only for wastewater with acute toxicity. A direct dependency between the magnitude of the toxic effect and the duration of contact of algae with toxicants is observed for about an hour. A further increase in the contact time almost does not increase the toxic effect. Conclusions. By increasing the contact time of algae with toxicants, it is possible to significantly increase the sensitivity of the method and, possibly, use it to evaluate low-toxic wastewater. However, for the final conclusions about the limits of sensitivity of the method, and, therefore, about the scope of its application, additional studies are needed.

Gravimetric Determination of Carbon Dioxide in Wines

1975 ◽  
Vol 58 (1) ◽  
pp. 136-139
Author(s):  
Graham A Castillo
Keyword(s):  
Carbon Dioxide ◽  
Vacuum Pump ◽  
Vacuum System ◽  
Reaction Flask ◽  
Magnesium Perchlorate ◽  
Titrimetric Method ◽  
Gravimetric Determination ◽  
Before And After ◽  
Gravimetric Procedure

Abstract A gravimetric determination of CO2 in wines was both accurate and relatively fast when compared with the titrimetric method. When 21 samples of lightly carbonated wine were analyzed by both methods the average results agreed within 0.2 mg (range of agreement from 0.1 to 5.0 mg CO2/100 ml wine). In the gravimetric procedure, the CO2 contained in the wines is converted into the carbonate by adding 50% NaOH to the previously chilled sample. An aliquot is introduced into a closed vacuum system. The CO2 is evolved by adding HCl and shaking and warming the reaction flask. The generated gases are pulled through the system by a vacuum pump. Along the path, the gases are dried and purified, and finally the CO2 is absorbed by Indicarb reagent between layers of anhydrous magnesium perchlorate. The absorption bulb is weighed before and after absorption of CO2.

scholarly journals The Determination of Total Carbon Dioxide in Water

1960 ◽  
Vol 37 (3) ◽  
pp. 444-460
Author(s):  
T. R. MILBURN ◽  
L. C. BEADLE
Keyword(s):  
Carbon Dioxide ◽  
Sodium Hydroxide Solution ◽  
Carbon Dioxide Concentration ◽  
Total Carbon ◽  
Original Sample ◽  
Dissolved Gas ◽  
Hydroxide Solution ◽  
Extraction Apparatus ◽  
Before And After

1. The method described involves extraction of the dissolved gas from an acidified sample in a modified van Slyke apparatus, and measurement of the electrical resistance of a standard sodium hydroxide solution before and after equilibration with the extracted gas. 2. The original sample must be not less than about 30 ml. for which a 10 ml. sample is drawn into the extraction apparatus. 3. There is a linear relation between the resistance finally measured and the total carbon dioxide content of the original sample up to a maximum determined by the strength of the standard hydroxide solution, which is thus adjusted to the desired range of carbon dioxide concentration, e.g. 0.005N-NaOH for 0-50 mg./l. and 0.02N for 0-200 mg./l. CO2. 4. The method is easily sensitive to 0.3 mg./l. in the range 0-50 mg./l. total carbon dioxide and about 1 mg./l. in the range 0-200 mg./l. With a rigidly standardized procedure increased accuracy was obtained so that replicate determinations on standard solutions in the 0-50 mg./l. range did not differ by more than 0.16 mg./l. 5. Precautions for handling samples containing carbon dioxide in solution prior to determination have been suggested. 6. About 15-20 min. are required for each determination and to Mrs D. E.

The Plasmin Inhibitors of Plasma

1964 ◽  
Vol 12 (01) ◽  
pp. 119-125 ◽  
Author(s):  
Y Shamash ◽  
A Rimon
Keyword(s):  
Human Plasma ◽  
New Method ◽  
Normal Amount ◽  
Caseinolytic Activity ◽  
Before And After ◽  
Plasmin Inhibitors

SummaryA new method for the assay of plasmin inhibitors in human plasma is described. The method consists of determination of the caseinolytic activity of a standard plasmin solution before and after incubation with the inhibitor, with lysine added to the mixture as a stabilizer of plasmin. Using this method, it was found that plasma contains enough inhibitors to inactivate 30 caseinolytic units of plasmin, or 10 times the normal amount of plasminogen in human plasma.

FRACTIONAL DETERMINATIONS OF URINARY 17-KETOSTEROIDS IN HYPEREMESIS GRAVIDARUM

1962 ◽  
Vol 41 (1) ◽  
pp. 123-128 ◽  
Author(s):  
Pentti A. Järvinen ◽  
Sykkö Pesonen ◽  
Pirkko Väänänen
Keyword(s):  
Hyperemesis Gravidarum ◽  
First Trimester ◽  
Control Group ◽  
Before And After ◽  
Daily Urine ◽  
First Trimester Of Pregnancy ◽  
The Difference

ABSTRACT The fractional determination of 17-ketosteroids in the daily urine was performed in nine cases of hyperemesis gravidarum and in four control cases, in the first trimester of pregnancy both before and after corticotrophin administration. The excretion of total 17-KS is similar in the two groups. Only in the hyperemesis group does the excretion of total 17-KS increase significantly after corticotrophin administration. The fractional determination reveals no difference between the two groups of patients with regard to the values of the fractions U (unidentified 17-KS), A (androsterone) and Rest (11-oxygenated 17-KS). The excretion of dehydroepiandrosterone is significantly higher in the hyperemesis group than in the control group. The excretion of androstanolone seems to be lower in the hyperemesis group than in the control group, but the difference is not statistically significant. The differences in the correlation between dehydroepiandrosterone and androstanolone in the two groups is significant. The high excretion of dehydroepiandrosterone and low excretion of androstanolone in cases of hyperemesis gravidarum is a sign of adrenal dysfunction.

DETERMINATION OF BLOOD CORTICOIDS USING THE IN VITRO RESIN UPTAKE OF 3H-PREDNISOLONE

1968 ◽  
Vol 57 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Hironori Nakajima ◽  
Mitsunori Murala ◽  
Masumitsu Nakata ◽  
Takeshi Naruse ◽  
Seiji Kubo
Keyword(s):  
Thyroid Function Test ◽  
Normal Subjects ◽  
Adrenal Function ◽  
Function Test ◽  
Before And After ◽  
Adrenal Response ◽  
Suppression Test

ABSTRACT The in vitro resin uptake of 3H-prednisolone was used for the determination of blood cortisol after addition of radioactive prednisolone followed by Amberlite CG 400 Type 1 to the test serum, and incubation of the mixture. The radioactivity of the supernatant was compared before and after the addition of the resin. The principle of this method is similar to that of the 131I-triiodothyronine resin uptake for the thyroid function test. The tests for the specificity, reproducibility and sensitivity gave satisfactory results. The mean basal value ± SD of the 3H-prednisolone resin uptake was 35.3 ± 9.2% in normal subjects, and 27.1 ± 4.8% in pregnant women. This method was valid in various adrenal function tests, i. e. the adrenal circadian rhythm, corticotrophin (ACTH) test, dexamethasone suppression test and the adrenal response to lysine-8-vasopressin. It proved to be a sensitive indicator of the adrenal function. These results suggest that this method should be useful for a routine adrenal function test.

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