Oxidation of metal-diethylenetriaminepentaacetate (DTPA)--complexes during drinking water ozonation.

This study investigates the oxidative transformation of diethylenetriaminepentaacetate (DTPA), a synthetic ligand, during drinking water ozonation. The rate coefficients for the reactions of CaDTPA3- and ZnDTPA3- with ozone were determined to be 6200 and 3500 +/- 150 M-1 s-1, respectively. The reactivity of Fe(III)DTPA2- towards ozone was found to be much lower (< 10 M-1 s-1), but near neutral pH the reactivity of the Fe(III)-complexes is dominated by [Fe(III)(OH)]DTPA3-. For the reaction of Fe[(III)(OH)]DTPA3- with ozone a rate coefficient of 2.4 +/- 0.2 x 10(5) M-1 s-1 was measured. The rate coefficients of the reactions of the ZnDTPA- and Fe(III)DTPA with OH radicals have been determined by a competitive method as 2.4 +/- 0.4 x 10(9) and 1.5 +/- 0.1 x 10(9) M-1 s-1, respectively at pH = 7. The degradation of low concentrations of DTPA complexes during ozonation was investigated in natural waters under drinking water relevant conditions. Based on our findings CaDTPA3- and ZnDTPA3- are judged as easily degradable. Fe(III)DTPA complexes showed a somewhat lower reactivity, but were still typically degraded by one order of magnitude at ozone dosages of approximately 20 microM (1 mg L-1) in the three natural waters tested. Molecular ozone was found to be the major oxidant for the metal-DTPA complexes during ozonation.

[The effect of long-term hypokinesia on the course of pathological processes in animals]. / Vliianie dlitel'noi gipokinezii na techenie patologicheskikh protsessov u zhivotnykh.

Reported are results of studying the development of pathology in rats and rabbits. Immobilization was found to markedly influence super-heating, local inflammation, and fever. In superheated animals, rise in the rectal temperature in the experiment and control proceeded at a similar speed; however, recovery of temperature in the control rats progressed significantly slower due to, probably, the hyper-compensatory reaction of animals to the thermal exposure. Life span of the control animals following heat exposure amounted to 160 +/- 13 min with a 100% lethality, whereas in the experimental animals the lethality rate was essentially lower and they lived much longer before death. At all times symptoms of inflammation in the experimental animals were more distinct and complications on the background of immobilization were more frequent and severe; edema of tissues exceeded that in the control by 36.6-49.0%. Local hyperthermia also was greater by 1.1-1.4 degrees C compared with the control. Observed was higher frequency of secondary infections and complications. According to the pathomorphological examinations, immobilization enhanced the alterative processes, inhibited formation of the demarcation area, suppressed melting of necrotic masses and engendered other signs of more serious pathology. Analysis of the course of pyrogenous fever evidenced shortening of the T upward phase and extension of the post-peak fever as an effect of long-term immobilization.

Contaminated environments in the subsurface and bioremediation: organic contaminants.

Due to leakages, spills, improper disposal and accidents during transport, organic compounds have become subsurface contaminants that threaten important drinking water resources. One strategy to remediate such polluted subsurface environments is to make use of the degradative capacity of bacteria. It is often sufficient to supply the subsurface with nutrients such as nitrogen and phosphorus, and aerobic treatments are still dominating. However, anaerobic processes have advantages such as low biomass production and good electron acceptor availability, and they are sometimes the only possible solution. This review will focus on three important groups of environmental organic contaminants: hydrocarbons, chlorinated and nitroaromatic compounds. Whereas hydrocarbons are oxidized and completely mineralized under anaerobic conditions in the presence of electron acceptors such as nitrate, iron, sulfate and carbon dioxide, chlorinated and nitroaromatic compounds are reductively transformed. For the aerobic often persistent polychlorinated compounds, reductive dechlorination leads to harmless products or to compounds that are aerobically degradable. The nitroaromatic compounds are first reductively transformed to the corresponding amines and can subsequently be bound to the humic fraction in an aerobic process. Such new findings and developments give hope that in the near future contaminated aquifers can efficiently be remediated, a prerequisite for a sustainable use of the precious-subsurface drinking water resources.

Initial reactions in the anaerobic oxidation of toluene and m-xylene by denitrifying bacteria.

Pseudomonas sp. strain T and Pseudomonas sp. strain K172 grow with toluene under denitrifying conditions. We demonstrated that anaerobic degradation of toluene was initiated by direct oxidation of the methyl group. Benzaldehyde and benzoate accumulated sequentially after toluene was added when cell suspensions were incubated at 5 degrees C. Strain T also grows anaerobically with m-xylene, and we demonstrated that degradation was initiated by oxidation of one methyl group. In cell suspensions incubated at 5 degrees C 3-methylbenzaldehyde and 3-methylbenzoate accumulated after m-xylene was added. Toluene- or m-xylene-grown strain T cells were induced to the same extent for oxidation of both hydrocarbons. In addition, the methyl group-oxidizing enzyme system of strain T also catalyzed the oxidation of each isomer of the chloro- and fluorotoluenes to the corresponding halogenated benzoate derivatives. In contrast, strain K172 only oxidized 4-fluorotoluene to 4-fluorobenzoate, probably because of the narrow substrate specificity of the methyl group-oxidizing enzymatic system. During anaerobic growth with toluene strains T and K172 produced two transformation products, benzylsuccinate and benzylfumarate. About 0.5% of the toluene carbon was converted to these products.

[Pharmacological agents for the correction of the processes of work capacity rehabilitation in flight personnel]. / Farmakologicheskie sredstva korrektsii protsessov vosstanovleniia rabotosposobnosti letnogo sostava.

Pharmacological correction of performance capability of rehabilitation processes in flight crews depends on the character and intensity of sustained loads under the influence of flight and corresponding changes of energoplastical synthesis in human organism. The authors make a proposal to influence upon the processes of energoproducts not only after the work (postlabour rehabilitation), and immediately in the process of work (current rehabilitation), but also before the flight activities (preventive rehabilitation). The article contains the results of administration of bemitil, panangin, asaparal, acephen, fenibut, natrium oxibutirate and ascorbic acid. There are recommendations for aviation physicians concerning the usage of these medications for performance capability correction of the flight crews.

[The electrolyte balance of the blood in dogs exposed to multiple +Gz overloads]. / Elektrolitnyi balans krovi sobak pri mnozhestvennykh peregruzkakh +Gz.

Experiments of the series were carried out using 7 noninbred dogs. In the first series, the animals were exposed to + GZ acceleration of increasing value once or twice a week during 5 months. Each exposure continued until distinct cardiac arrhythmias were seen in ECG. Two weeks after the onset of exposure the dogs displayed hyponatremia and higher K-Na coefficient and two months later they showed hyperkalemia and hypermagnesemia which led to a 1.5 G increase of acceleration tolerance. In the second experimental series, the animals exhibited a beneficial effect of hypermagnesemia on circulation parameters and frequency of cardiac arrhythmias in response to a single + GZ exposure. These observations have demonstrated that electrolyte balance plays an important part in the development of adaptation to sustained acceleration.

[Hypovolemic reactions of man and animals to exposure to +GZ load factors of increasing intensity]. / Gipovolemicheskie reaktsii cheloveka i zhivotnykh pri vozdeistvii peregruzok +GZ narastaiushchei intensivnosti.

Maximal variations of the circulating blood and plasma volumes after water load and/or exposure to increasing +GZ were investigated in manned and animal studies. The animal study demonstrated that the relative changes in the circulating blood and plasma volumes can be calculated using hematocrit or hemoglobin values. On the 2nd minute after exposure to increasing +GZ of up to 14.5 G the animals showed a decrease (by 11.7%) of the circulating blood volume which was primarily associated with plasma losses. The change was not appreciably modified by the use of an anti-G suit. In the manned studies the decrease was 5.9% during exposure to 7 G and 11% during exposure to 9 G with an anti-G suit used. These observations show that the acceleration duration and value play an important part in the mechanism of plasma filtration in response to an increase in the hydrostatic pressure.

[Adaptive and cumulative effects in the dog exposed to routine +GZ acceleration]. / Adaptatsionnye i kumuliativnye éffekty u sobak pri sistematicheskom vozdeistvii peregruzok napravleniia +GZ.

The development of adaptive and cumulative effects was investigated in 13 noninbred dogs regularly exposed to +GZ acceleration: Group I dogs were exposed 3 to 4 times a week for 2 months and Group 11 dogs were exposed 1 to 2 times a week for 5 months. The tolerance threshold was evaluated with respect to ECG abnormalities. The study of circulation reactions and acceleration tolerance threshold revealed the predominant development of adaptive changes that were more distinct in Group 11 dogs. Cumulative effects in the form of functional disorders of pulmonary vessels occurred in all experimental dogs but less frequently in Group II dogs. Morphological lesions of the lung tissue developed in Group I animals after 2 to 3 exposures and in Group II animals after 2 to 3 months, the incidence rate being lower in those latter. These findings suggest that adaptive and cumulative effects in response to regular exposures to threshold +GZ acceleration develop more or less in parallel.

[Incidence and nature of electrocardiographic disorders in the dog after single and multiple exposure to +Gz]. / Chastota i kharakter narushenii élektrokardiogrammy u sobak pri odnokratnom i mnogokratnom deistvii peregruzok +GZ.

Pathological changes of the ECG were examined in 10 adult dogs exposed to +Gz once a day or 3 times a day for three days a week during 2 to 12 weeks. In response to acceleration all of the dogs developed ECG changes. The frequency and level of these disorders were dependent on the acceleration magnitude and the health state that varied during repeated exposure. These findings were used to develop a 5-score scale for measuring ECG disorders and to identify phase changes in acceleration tolerance during repeated exposure to +Gz. It was also demonstrated that animals can be specifically trained to tolerate sustained and high acceleration +Gz.

[Effect of tranquilizers on the motivation components and the tactics of operator activities]. / Vliianie trankvilizatorov na motivatsionnye komponenty i taktiku deiatel'nosti operatora.

The effect of tranquilizers on the motivation components and tactics of operator's activities was investigated, using a model of discrete tracking of a moving object. The correlation-matrix method was applied to determine the region of no error correction. It was shown that specific changes in the tactics of operator's activities developing in response to tranquilizers and reduced motivation were identical. It appears probable that decreased motivation of failure avoidance forms the phenomenon of preparedness of risk taking and optimization of operator's activities when tranquilizers are used under psychological conflict conditions.

[Biochemical shifts in the blood plasma of dogs in multiple G-load exposure]. / Biokhimicheskie sdvigi v plazme krovi sobak pri mnogokratnom vozdeistvii peregruzok.

For 3 months experimental dogs were exposed to +Gz acceleration applied 3 times a day for 3 days a week. The initial acceleration value was 8-9 G, then the parameter varied, depending on the tolerance limit which was evaluated with respect to heart rate disorders. Biochemical measurements showed the largest changes (decrease in total protein, increase in sugar, bilirubin, cholesterol, alkaline phosphatase and transaminases) after the first day of the repeated exposure to +Gz. Following 1-3 months of the exposure, the changes decreased significantly; however, the K+ concentration continued to decline and that of alkaline phosphatase continued to increase. The results obtained indicate the development of adaptation to repeated +Gz exposures which differs from that to short-term exposures.

[Characteristics of the course of pyrogenal fever in animals after prolonged hypokinesia]. / Ob osobennostiakh techeniia pirogenalovoi likhoradki u zhivotnykh posle dlitel'noi gipokinezii.

The experiments on rabbits with pyrogenal fever and amidopyrine injection have demonstrated that their 15- and 30-day exposure to hypokinesia produces changes in the reactivity of thermoregulating centers, their overexcitation and depletion. These changes are more distinct after 15-day hypokinesia.

[Effect of long-term hypokinesia on the course of acute aseptic inflammation]. / Vliianie dlitel'noi gipokinezii na techenie ostrogo asepticheskogo vospaleniia.

White rats were kept under hypokinetic conditions for 15, 28 and 60 days. By physiological, microbiological and morphological methods it was demonstrated that hypokinesia had an adverse effect on the clinical development of aseptic inflammation. This effect included a more marked edema and its delayed resorption, an increased temperature of the inflammatory focus, an increased number of infectious complications, involving necrotic foci and ulcerations, enhanced alteration processes, inhibited formation of the demarcation zone, generalized inflammation, etc. Resistance to phlogogenic stimulation fell down to a minimum during the first two hypokinetic weeks; afterwards it gradually returned to normal but did not recover entirely even after 60 days of hypokinesia. Following 15- and 28-day hypokinetic experiments resistance to phlogogenic agents reached the pretest level within 7 days of the recovery period.

[Psychopharmacology in aviation and astronautics]. / Psikhofarmakologiia v aviatsii i kosmonavtike.

Flights aboard modern vehicles are associated with high nervous-emotional and physical stresses. This may induce depletion of reserve capabilities, development of fatigue and, consequently, reduction of work capacity of crewmembers. The paper discusses approaches and results of the use of drugs by pilots and cosmonauts in order to alleviate their fatigue and emotional stress. It gives indications and contraindications for the adminstration of stimulants and tranquilizers. On the basis of a comprehensive analysis of the literature data and their own findings, the authors draw the conclusion that the use of stimulants and anxiolytics may increase the level of reliability and performance of air- and spacecraft pilots during programmed and, particularly, contigent situations of the flight.