Determination of laminar burning velocity of methane/air flames in sub atmospheric environments

The global energy demand enhances the environmental and operational benefits of natural gas as an energy alternative, due to its composition, mainly methane (CH4), it has low polluting emissions and benefits in energy and combustion systems. In the present work, the laminar burning velocity of methane was determined numerically and experimentally at two pressure conditions, 0.85 atm and 0.98 atm, corresponding to the city of Medellín and Caucasia, respectively, located in Colombia. The environmental conditions were 0.85 atm, 0.98 atm, and 295±1 K. The simulations and experimental measurements were carried out for different equivalence relations. Experimental laminar burning velocities were determined using the burner method and spontaneous chemiluminescence technique, flames were generated using burners with contoured rectangular ports to maintain laminar Reynolds numbers for the equivalence ratios under study and to reduce the effects of stretch and curvature in the direction of the burner's axis. In general, the laminar burning velocity fits well with the numerical results. With the results obtained, a correlation is proposed that relates the laminar burning velocity with the effects of pressure, in the form SL=aPb, where a and b are model constants. Sensitivity analysis was performed using the GRI-Mech 3.0 mechanism which showed that the most sensitive reaction was H+O2=O+OH (R38). Additionally, it was found that the reactions H+CH3 (+M)=CH4 (+M) (R52), 2CH3 (+M)=C2H6 (+M) (R158), and O+CH3=H+CH2O (R10) dominate the consumption of CH3 which is an important radical in the oxidation of methane, this analysis is carried out for equivalence ratios of 0.8 and 1.0, and atmospheric pressures of 0.85 atm and 0.98 atm

Evaluation of immunotoxicity of the extended-release form of Afobazol

The research of immunotoxicity of extended-release form of Afobazol was conducted on male CBA, C57BL/6 and F1 hybrids (CBA×C57BL/6) mice. Afobazol was administered per os for 14 days in doses of 12 mg/kg and 120 mg/kg. Control group received a placebo. Weight of thymus, spleen and popliteal lymph nodes was not affected by the extended-release form of Afobazol in doses of 12 mg/kg and 120 mg/kg in F1 hybrids (CBA×C57BL/6) mice compared to the control group (p> 0.05). Cellularity of thymus was significantly increased by the extended-release form of Afobazol in dose of 12 mg/kg (p< 0.01 vs control group). Administration of the extended-release form of Afobazol in doses of 12 mg/kg and 120 mg/kg decreased spontaneous chemiluminescence activity of peripheral blood lymphocytes in 2.0 and 2.2 times, in dose of 120 mg/kg level integral chemiluminescence response S was decreased in 2.4 times (p< 0.05 vs control group). Phagocytic activity of peritoneal macrophages and antibody production in F1 hybrids (CBA×C57BL/6) mice were not affected by administration of the extended-release form of Afobazol in doses of 12 mg/kg and 120 mg/kg (p > 0.05 vs control group). 14 days of the extended-release form of Afobazol in doses of 12 mg/kg and 120 mg/kg did not cause any significant change to intensity of delayed-type hypersensitivity reactions (p> 0.05 vs control group). The results of the study allow us to conclude that administration of the extended-release form Afobazol in the range of studied doses does not induce immunotoxicity.

Monocyte Chemiluminescence Traits in Gastric Cancer

Aim. A study of monocyte chemiluminescent activity at variant stages of gastric cancer.Materials and methods. The study enrolled 90 gastric cancer patients and 70 healthy donors. Spontaneous and induced chemiluminescence in monocytes was assessed for 90 min with a “BLM 3607” 36-channel chemiluminescence analyser (Russia). Opsonized zymosan-induced chemiluminescence enhancement was measured as a ratio of the areas under the induced vs. spontaneous chemiluminescence curves, the activation index. Statistical significance was estimated with the Mann—Whitney criterion (p < 0.05).Results. The maximal spontaneous monocyte chemiluminescence intensity significantly decreased in stage IV gastric cancer patients compared to the control cohort (p = 0.035). Time to maximum in spontaneous chemiluminescence increased in all gastric cancer patients vs. control (p = 0.001), and in stage IV gastric cancer vs. stage I patients (p = 0.043). The areas under a curve in spontaneous and induced monocyte chemiluminescence increased in all gastric cancer patients vs. control (p = 0.001), and in stage IV gastric cancer vs. stage I patients (p = 0.037). The activation index was higher in all gastric cancer cases compared to control (p = 0.001).Conclusion. All patients with gastric adenocarcinoma, irrespective of the stage, revealed changes in the monocyte chemiluminescence activity, i.e. a longer time to maximum in spontaneous chemiluminescence and larger area under the curve of spontaneous and induced chemiluminescence, the activation index. Maximal monocyte spontaneous chemiluminescence intensity diminished in stage IV gastric cancer compared to the control cohort. Immune activity reflected in monocyte chemiluminescence correlates with the stage of gastric adenocarcinoma.

THE INCREASED KINETICS OF H2O2-INDUCED CHEMILUMINESCENCE IN THE PATIENTS WITH LONG-TERM CONSEQUENCES AFTER CEREBRAL CONTUSION

Purpose of the study. The aim was to study in the patients with long-term consequences after cerebral contusion the intensity of spontaneous and H2O2-induced chemiluminescence in order to evaluate the early fast-flowing reactions caused by oxidative stress and associated with the formation of primary radicals such as free radical oxidations. Materials and Methods. Forty-two patients with long-term consequences after cerebral contusion were investigated (39,04 ± 12,84 years mean age; mean onset years 32,56 ± 6,4) where both spontaneous and H2O2-induced chemiluminescences were measured directly by HPLC-chemiluminescence assay. Results. The study have showed that sera of the investigated patients with long-term consequences after cerebral contusion have the increased H2O2-induced chemiluminescence associated with the high amplitude of «fast» burst and the tendency to increase of spontaneous chemiluminescence (p = 0,039 and p = 0,58, accordingly). Thus, the patients with long-term consequences after cerebral contusion showed the abnormal high kinetics of H2O2-induced chemiluminescence (p < 0,05). The statistically significant increase serum Н2О2-induced chemiluminescence intensity detected in examined patients (3085,6 ± 114,2 vs 669,1 ± 214,83 controls) have showed the development of certain oxidative stress processes in this category of patients associated with the increasing of primary free radical reactions and their activity were getting increased with the progression of the disease duration (p < 0,05). Conclusions. The study provides the novel data revealing the increased kinetics of H2O2-induced chemiluminescence in the patients with long-term consequences after cerebral contusion accompanied by the tendency to increase of spontaneous chemiluminescence that may play the certain pathogenetic role. Keywords: H2O2-induced chemiluminescence, long-term consequences after cerebral contusion, oxidative stress.

OXYGEN-DEPENDENT PHAGOCYTOSIS OF BLOOD MONOCYTES IN CHILDREN WITH HELICOBACTER PYLORI-ASSOCIATED GASTRIC AND DUODENAL EROSIONS AND ULCER

The aim of the research is to study oxygen-dependent phagocytosis of blood monocytes in children with gastric and duodenal erosions and ulcers by chemiluminescence analysis. The subjects of the research were blood monocytes, extracted from blood in 44 children with gastric and duodenal erosions and ulcers in the ages from 11 to 18 years. Microscopic tests for the bioptats of gastric mucosa of both standard regions and edges of ulcer defects had resulted in the determination of 2 groups of the patients with gastric and duodenal erosions and ulcers. The 1st group was represented by Helicobacter pylori high dissemination. As for the 2nd group, the patients showed low bacterization. The tests for luminol-dependent hemiluminescence of blood monocytes in patients with H. pylorihigh dissemination of gastric and duodenal mucosa demonstrated the significant increase of the intensity and the growth of areas both under the curve of spontaneous response and under the curve in the zimozan-induced process as compared to the monocyte activity in the group with low dissemination. Following the lucigenin- dependent chemiluminescence reactions in the group with H. pylori high dissemination we had found significant increase of the time of approaching the peak in both spontaneous response and zimozan- induced processes while the activation index was higher in comparison with phagocyte activities of monocytes in the group with low dissemination. Further stage of the research was to identify CagA-positive strains of H. pylori in the children with gastric and duodenal erosions and ulcers. Studying chemiluminescence activity of blood lymphocytes in the patients with anti-CagA antibodies we found the true increase of the time of reaching the peak, the intensity and the area under the curve in spontaneous process in luminol-dependent response and the time of reaching intensity peak and the intensity of spontaneous chemiluminescence reaction, lucigenin being an activator. So we marked the increase of the activity of oxygen-dependent phagocytosis of blood monocytes in children with H. pylori associated with gastric and duodenal erosions and ulcers related to H. pylori increased bacterization. The growth of H. pylori dissemination results in the higher stage of stomach mucosa inflammation. Therefore active phagocytes generate more intensively the formation of active forms of oxygen, free radicals and the products of peroxide oxidation. CagA-positive strains of H. pylori, as a rule, are associated with the higher level of inflammatory activity than CagA-negative ones. As a result of such influence the functional activity of monocytes increases, because they are «professional » phagocytes. The ability to perform phagocytosis is better expressed in them as compared to other leukocytes.

Neurotoxic Effects oftrans-Glutaconic Acid in Rats

trans-Glutaconic acid (tGA) is an unsaturated C5-dicarboxylic acid which may be found accumulated in glutaric aciduria type I, whose pathophysiology is still uncertain. In the present work it was investigated thein vitroeffect of increasingtGA concentrations on neurochemical and oxidative stress parameters in rat cerebral cortex. We observed that Na+, K+-ATPase activity was reduced bytGA, but not creatine kinase, respiratory chain complex IV, and ATP synthase activities. On the other hand,tGA significantly increased lipid peroxidation (thiobarbituric acid-reactive species levels and spontaneous chemiluminescence), as well as protein oxidative damage (oxidation of sulfhydryl groups).tGA also significantly decreased nonenzymatic antioxidant defenses (TRAP and reduced glutathione levels). Our data suggest thattGA may be neurotoxic in rat brain.