Course Of Changes In Concentrations Research Articles

Comparative Аssessment of Еmission Рroducts Distribution from Siberian Aluminum Plants

The results of a comparative analysis of the distribution of the components of the Bratsk (BrAZ), Irkutsk (IrkAZ), Sayanogorsk (SAZ) and Krasnoyarsk (KrAZ) aluminum components emissions from the air onto the snow cover are presented. It was found that the dependence of the decrease in the concentration of fluorine, sodium and lithium in the snow cover with distance from these industries is exponential. The same course of changes in the concentrations of Al, F, Ca, Mg, Li, Si, As, Zn, Sr, Sb in the snow water filtrate in the KrAZ, BrAZ and IrkAZ emissions zones was established. This course of concentration changes differs from that of the same elements in the background region. Based on the calculation of the element enrichment coefficient in the solid sediment of the snow cover, the anthropogenic origin of Zn, As, Sb in the region of influence of BrAZ and KrAZ emissions is shown. Based on the calculation of the element enrichment factor in snow water, the natural origin of Zn, As, Sb in snow water is shown in the area of impact of BrAZ and KrAZ emissions (from 1 km to 5–7 km). It is suggested to reduce fluoride emissions in the source by using lithium additives in the electrolyte. To reduce the emission distribution range, it is suggested to precipitate the aerosols included in the emissions within a radius chosen based on the exponential dependence of the deposition, and also to apply the approaches of ecological landscaping and improvement of the industrial territory.

Research on the influence of anaerobic stabilization of various dairy sewage sludge on biodegradation of polycyclic aromatic hydrocarbons PAHs with the use of effective microorganisms

Sewage sludge was taken from a dairy WWTP belonging to Mlekovita Cooperative in Wysokie Mazowieckie. There were excess sludge, flotation sludge and a mixture of excess and flotation sludge from pre-treatment of dairy sewage.The initial content of 16 PAHs in excess sludge before fermentation was approximately 689µg·kg−1 in dry mass, whereas in post-flotation sludge (which constituted around 30% of raw sludge) it was approximately 95µg·kg−1 in dry mass. A mixture of excess and flotation sludge had the content of 497,7µg·kg−1 in dry mass. Through comparison of particular hydrocarbons content in raw sewage sludge to the total PAHs content, it was shown that tricyclic compounds, which constituted 46,3% of the PAHs sum (excess sludge), and tetracyclic compounds, which constituted 60,0% of the PAHs sum (flotation sludge), were the dominating fractions.In the sludge subjected to fermentation in reactors with mixed sludge and surplus activated sludge, the general trend of the course of changes in concentrations of PAHs was similar. Both in the sludge inoculated with EM and in that not inoculated with EM, a significant increase in the total PAHs contents was observed in the first fermentation phase (acidic fermentation) after 7 days of the process. Addition of EM into the sludge did not prevent the PAHs release, and therefore higher concentrations of PAHs sum were recorded during the hydrolysis stage than in sludge before fermentation. A decrease in the sum of PAHs was observed after 2 weeks of fermentation in relation to the quantity observed after 1 week of fermentation (except from post-flotation sludge). In the following weeks, there was further decrease in the concentration of the 16 PAHs sum in all sludge types. However, in sludge without EM inoculation, it was lower than in sludge with EM inoculation. The loss of the majority of tested hydrocarbons was reported in the final phase of fermentation.

USING TISSUE AMMONIA AND FERMENTATIVE VOLATILE CONCENTRATIONS AS INDICATORS OF BENEFICIAL AND STRESSFUL MODIFIED ATMOSPHERES FOR LEAFY AND FLORAL VEGETABLES

Ammonia, a product of protein catabolism associated with senescence of leafy green vegetables, is toxic to plant cells if not efficiently re-incorporated by glutamate synthetase. In experiments on various intact and fresh-cut leafy and floral vegetables (broccoli, cauliflower, romaine lettuce, spinach and sugar snap peas) at 5-7.5°C, tissue ammonia concentrations were measured as a possible indicator of stressful modified atmospheres and compared with the time course of changes in concentrations of the fermentative volatiles ethanol and acetaldehyde. In spinach, increases in ammonia were observed with high CO 2 atmospheres and were associated with darkening of leaf tissues. In cauliflower florets, increases in ammonia and tissue discoloration were associated with the increases in fermentative volatiles in 15% CO 2 atmospheres, but minimal changes in ammonia and the fermentative volatiles occurred in air or non-damaging low O 2 atmospheres with 7.5% CO 2 . Increases in ammonia concentrations in sugar snap peas were also associated with increases in fermentative volatiles in 12 and 18% CO 2 atmospheres with 3% 0 2 ; these conditions resulted in browning discoloration. The same CA conditions resulted in no damage and only small increases in ammonia and fermentative volatiles in broccoli florets. In cut romaine lettuce, atmospheres with 9% but not 6% CO 2 resulted in notable increases in ammonia, but ammonia was not much affected by differences in O 2 concentrations (0.2, 1.0, or 21%). Increases in fermentative volatiles only occurred in cut lettuce stored in 0.2% O 2 alone or in combination with high CO 2 . These results indicate that ammonia may be a useful indicator of stress in modified atmosphere storage of leafy tissues. In cauliflower and spinach, atmosphere conditions that resulted in increases in ammonia also resulted in increases in fermentative volatiles. In romaine lettuce, ammonia concentrations indicated stressful atmospheres that were not associated with increases in fermentative volatiles. In other vegetables (sugar snap peas), increases in ammonia and fermentative volatiles had different time courses.

Adrenocortical responsiveness to infusions of physiological doses of ACTH is not altered in posttraumatic stress disorder

Early studies of posttraumatic stress disorder (PTSD) reported that abnormal function of the hypothalamic–pituitary–adrenocortical (HPA) system was associated with the disorder. However, subsequent studies attempting to identify a specific aspect of HPA dysfunction that characterizes PTSD have been marked by considerable inconsistency of results. A facet of HPA regulation that has been considered but not definitively investigated is the possibility that the responsiveness of the adrenal cortex to physiological concentrations of adrenocorticotropin (ACTH) is diminished in PTSD. Relationships between PTSD and the adrenal androgen dehydroepiandrosterone (DHEA) have also been postulated. In this study we investigated the magnitude and time course of changes in concentrations of plasma cortisol and DHEA in response to bolus infusions of physiological doses of ACTH 1–24 in PTSD patients and control subjects. We found no evidence for PTSD-related alterations in cortisol or DHEA secretion in response to stimulation by low doses of ACTH and conclude that adrenocortical responsiveness is normal in PTSD. Results from this and other studies suggest that the occurrence of defects in HPA function in PTSD may be specific responses to particular combinations of trauma type, genetic susceptibility, and individual history.

Visualizing localized dynamic changes during epileptic seizure onset in vivo with diffuse optical tomography

Diffuse optical tomography (DOT) is a promising functional imaging modality due to its ability to provide quantitative and dynamic tomographic imaging of brain functions. This pilot study was conducted to demonstrate that DOT can be used to visualize the changes in local hemodynamics during seizures. The focal seizure was induced by microinjection of 10 microl of 1.9 mM GABAA antagonist bicuculline methiodide (BMI) into the left parietal neocortex of male Harlen Sprague-Dawley rats, which was imaged by a multispectral continuous-wave DOT system. Functional images were obtained by our finite element based image reconstruction algorithm. A series of dynamic 2D images were obtained to delineate the time course of concentration changes of oxyhaemoglobin, deoxyhaemoglobin, and total hemoglobin in the rat brain during seizure onset. The BMI induced epileptic foci were localized and observed over time from the images obtained. Our results suggest that diffuse optical tomography may be a promising modality for epilepsy imaging due to its ability to localize epileptic foci as well as its potential to map the functional activity in the area of human cerebral cortex in planning of epilepsy surgery.

Equilibrium of Nucleotides in the Dogfish Brain

In the past, the results of experiments on the time course of concentration changes of adenylates, phosphocreatine, and free creatine in muscle appeared compatible with an equilibrium hypothesis involving only the Lohmann and the myokinase reactions. Other reports, however, denied the applicability of the equilibrium hypothesis to the same tissue. The controversy may have been due to the high probability of experimental errors since time sampling was performed at second intervals. We presently test the hypothesis in the living brain of the small-spotted dogfish shark (Scyliorhinus canicula), an animal-model allowing for timing of sampling at hourly intervals. According to our earlier work, the dogfish shark can easily be resuscitated 8.2 h on average after being brought into the state of "suspended animation" at 0 degree C body temperature and exposed, out of water, to an atmosphere of nitrogen gas. To obtain a complete mathematical description of the time course of concentration changes of brain adenylates and phosphocreatine, we devised a kinetic model based on principles of classical multicompartmental analysis and biochemical kinetics. Model testing of the equilibrium hypothesis resulted in very good agreement between the hypothesis and our experimental data. Time-course modeling, achieved by simultaneously fitting the time series of our data by the set of four equations constituting our model resulted in an excellent agreement between data points and the computed curves. Finally, modeling of the depletion profiles of brain energy status concerning three of its descriptors (energy charge, total adenylate, and primary energy stores expressed in high-energy phosphate equivalents) allowed for a correlation to be established between energy status and the "revival time," a valuable physiological descriptor of tolerance.

Dynamics of cytokine production in human peripheral blood mononuclear cells stimulated by LPS, or infected by Borrelia.

To specify the role of individual cytokines in the immune response to pyrogens, isolated and cultivated human peripheral blood mononuclear cells (PBMC) were used for the experiments. Different pyrogens (lipopolysaccharide from Escherichia coli - LPS and live Borrelia afzelii) were applied and the time course of changes in concentrations of different cytokines in the medium was followed using the ELISA method. It was found that nonstimulated human PBMC proliferate under in vitro conditions and produce IL-6, TNF-a, IL-10 and finally also IL-1b. Productions of IL-12 and INF-g are not changed. Proliferation of PBMC is potentiated after incubation with LPS or live Borrelia. PBMC stimulated by LPS increase the net production (stimulated minus unstimulated) of IL-1b and TNF-a significantly, while production of IL-6 was smaller. A delayed increase in the production of IL-10 was also observed. Productions of IL-12 and INF-g were not influenced. In contrast to LPS, stimulation of PBMC with live Borrelia, increases also the production of IL-12 and IFN-g, besides IL-1b, TNF-a, IL-6 and IL-10. Productions of IL-1b, IL-6 and TNFa increased immediately after incubation with both LPS and Borrelia, while productions of IL-12 and INF-g begin to increase 8 hours and production of IL-10 12 hours after stimulation. Data indicate that stimulation with different pyrogens may activate the cells of the immune cascade in a different way. Stimulation of BPMC by LPS seems to activate the initial steps of the immune response (macrophages and granulocytes) only, while infection with live Borrelia also stimulates the later phase of the immune response, probably due to effect of initially produced cytokines.

Cytochemical localization of guanylate cyclase in photoreceptor cells of the mouse.

Light-stimulated excitation causes a decrease of the cGMP concentration in vertebrate photoreceptor cells. The cGMP content is restored by the catalytic action of a guanylate cyclase (EC 4.6.1.2). The spatial distribution of guanylate cyclase was determined cytochemically in rod visual cells of the mouse. In retinal tissue of the mouse guanylate cyclase was found throughout the photoreceptor cells, in the outer and the inner segments, and was especially prominent in the cilia and in elongations of cilia extending into the outer segments. A reaction product of adenylate cyclase (EC 4.6.1.1) could not be demonstrated in vertebrate rod outer segments. The relatively high amount of guanylate cyclase in the inner segments and the cilia may contribute-at least in part-to the actual concentration and the time course of concentration changes of the cGMP concentration in rod outer segments.

Regulation of rCBF by diffusible signals: An analysis of constraints on diffusion and elimination

AbstractLocal changes in cerebral hemodynamics are observed within a few hundred milliseconds of changes in neural activity. If hemodynamic responses are mediated by passive diffusion of a spatial signal (from the site of neural activity to the microvessels) then the dynamics of the response suggest a lower limit on the signal's apparent diffusion and elimination. The aim of this work was to estimate these limits and narrow the field of possible candidate substances.A simple biophysical simulation was used to examine how the time course of concentration changes in a spatial signal, at the site of action (microvessels), depends on key diffusion parameters (source geometry, apparent diffusion and elimination half‐life). The simulations suggested (1) that the rise in signal concentration is mostly a function of source geometry and diffusion. Conversely falls in concentration depend on elimination and (2) even when sources are very sparsely distributed Nitric Oxide would have a sufficiently fast diffusion and elimination to signal the early components of activity‐dependent hemodynamic response by passive diffusion. © 1995 Wiley‐Liss, Inc.

C-reactive protein in femoral head necrosis.

Serum concentrations of C-reactive protein (CRP), alpha 1-antitrypsin, orosomucoid, and haptoglobin were determined in 28 patients with a medial fracture of the femoral neck. The serum concentrations were compared with the result of hip scintigraphy with technetium-99m pyrophosphate, a method which can detect femoral head necrosis and predict the development of late segmental collapse. Serum concentrations of the four acute-phase proteins were measured immediately before osteosynthesis and at the time of hip scintigraphy 1 to 4, 8 to 13, and 37 to 47 days postoperatively. During the same period 15 patients had constantly normal, five varying abnormal/normal, and eight constantly abnormal scintigrams, the latter indicating femoral head necrosis. All four acute-phase proteins had a typical course of concentration changes, which were most pronounced for CRP. However, none of them were useful for the detection of femoral head necrosis or the prediction of late segmental collapse, since the observed serum concentrations could not be used to distinguish between the three scintigraphic groups.