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At least 19 recordsLinked to original sources
PubMed2026

In situ product monitoring in heterogeneous reaction of gaseous trimethylamine on Fe2O3/Fe(NO3)3: Effect of environmental factor and particle property.

Gas-particle reactions represent an important atmospheric heterogeneous transformation process for organic amines (OAs). Environmental factors and particle properties may impact the gas-particle reaction products. Although the products from gas-particle reactions can be monitored by various in situ techniques, related data remain scarce. Here, the interfacial and gaseous products from the reaction of trimethylamine on Fe2O3/Fe(NO3)3 particles under light irradiation with mixed NO2, O2, SO2 and H2O were monitored using in-situ diffuse reflectance Fourier transform infrared spectroscopy and proton transfer reaction time-of-flight mass spectrometry. Dark reaction of gaseous trimethylamine on Fe2O3/Fe(NO3)3 generated two interfacial products types: N-containing ones (CH3NCH2, CH3NO2, (CH3)2NCHO, and CH3N(OH)CHO) and N-free ones (alcohols, aldehydes and acids), both accumulating with reaction progression. Light irradiation and O2 oxidation enhanced formation of these products, while NO2 promoted the production of CH3NO2 and (CH3)2NCHO. H2O and SO2 occupied the active sites of particles to inhibit the formation of all products. Compared to Fe(NO3)3, Fe2O3 showed absolute dominance in contribution to the formation of products. Considering the smaller particle size of Fe2O3 and excess Fe(NO3)3, the physical mixing of them reduced the generation of interfacial products. Furthermore, gaseous products of CH3OH, HCHO, CH3CHO, HCOOH and CH3COOH detection clarified the N-free interfacial products. The presence of Fe(NO3)3 inhibited the formation of HCOOH and favored the formation of CH3CHO in the gas phase. By combining product information with thermodynamic calculations, the heterogeneous reaction pathways of trimethylamine were tentatively proposed. These findings provide a guiding significance for the migration of OAs in real atmospheric environment.

Methylamines↗
PubMed1979

Heterogeneous phase reactions of Martian volatiles with putative regolith minerals.

The chemical reactivity of several minerals thought to be present in Martian fines is tested with respect to gases known in the Martian atmosphere. In these experiments, liquid water is excluded from the system, environmental temperatures are maintained below 0 degrees C, and the solar illumination spectrum is stimulated in the visible and UV using a Xenon arc lamp. Reactions are detected by mass spectrometric analysis of the gas phase over solid samples. No reactions were detected for Mars nominal gas over sulfates, nitrates, chloride, nontronite clay, or magnetitie. Oxidation was not observed for basaltic glass, nontronite, and magnetite. However, experiments incorporating SO2 gas--an expected product of volcanism and intrusive volatile release--gave positive results. Displacement of CO2 by SO2 occurred in all four carbonates tested. These reactions are catalyzed by irradiation with the solar simulator. A calcium nitrate hydrate released NO2 in the presence of SO2. These results have implications for cycling of atmospheric CO2, H2O, and N2 through the regolith.

Atmosphere↗
PubMed1978

The influence of pH on the conductance of lipid bimolecular membranes in relation to the alkaline ion transport induced by carboxylic carriers grisorixin, alborixin and monensin.

The influence of the pH on the stability and stoichiometry of the complexes formed by carboxylic-antibiotics such as grisorixin, alborixin and monensin with alkaline and alkaline earth cations has been investigated. The maximum values of bimolecular lipid membrane conductance are obtained with grisorixin and potassium ion. The conductance-pH curves show a very pronounced maximum in the neutral pH range. The results are analysed on the basis of a dimeric form of the ionophore in the complex and the possibility of having several charged complexes resulting from an heterogeneous reaction, the number of each complexed form depending on the pH of the bulk solutions.

Anti-Bacterial Agents↗
PubMed1979

[Clinical aspects of hypertensive crises].

Hypertensive crises were studied in 80 patients. In severe cases the ECG provided evidence of systolic overloading of the left ventricle with intensification of coronary circulation and development of acute myocardial ischemia. Phase analysis showed prolongation of the mechanical systole with increase of the myocardial index. In more complicated cases there was a more evident hypodynamic syndrome with marked myocardial insufficiency. Hemodynamic disturbance were marked by a sharply increased peripheral resistance with a heterogenous reaction of the cardiac output. Blood supply to the cerebral tissue reduced sharply with an increase in the resistance of cerebral vessels. Renin activity was directly related to the severity of the crisis. A sharp onset of cerebral and cardiac ischemia was marked by changes in the antigen albumin. Timely diagnosis and differentiated treatment made it possible to avoid vascular complications in hypertensive crisis.

Acute Disease↗
PubMed1978

[Role of heterogenized cellular antigens in cross immunity reactions in paramyxovirus infections].

Heterogenized antigens similar to the antigens of sheep and guinea pig red blood cells were revealed by indirect immunofluorescence in tissue cultures infected with parotitis virus. Participation of these antigens in cross immunofluorescence reactions observed in tissue cultures infected with various paramyxoviruses and in a suspension of erythrocytes loaded with these viruses was established. It was shown that immunization of children with parotitis virus was accompanied by a specific anamnestic reaction for heterogenized antigens. It is supposed that the corresponding antibodies can take part in cross serological tests with parainfluenza viruses.

Animals↗
PubMed1977

Cellology of HLA. 22. Heterogeneity of cellular reactions in negative HLA-D typing.

We have demonstrated that in more than half of the mixed lymphocyte reactions, proliferative reactions, in which responders were reacted against HLA-D-compatible homozygous typing cells, were significantly greater than zero. These reactions often masked the true HLA-D identity of the cells under test, as was subsequently shown by primed lymphocyte testing.

HLA Antigens↗
PubMed1975

Antigenic heterogeneity in patients with reactions in borderline leprosy.

Fifteen patients with borderline leprosy who developed "reversal" reactions were studied from the inception of treatment. Thirteen showed an appreciable increase in lymphocyte transformation (LT) when preparations of Mycobacterium leprae were used as antigen. The LT responses to either "whole" or "sonicated" preparations of the bacillus in these 15 patients and in nine others also in reaction correlated with the clinical presentation. Those with skin disease predominating in the reaction showed an appreciable increase in LT when whole M leprae was used as antigen. Those with nerve disease predominating showed an increase with sonicated M leprae. In those with both skin and nerve disease there was an increase with both antigen preparations. The ratios of the LT test results (whole to sonicated M leprae) showed highly significant differences between the three groups.

Adolescent↗
PubMed1979

Evaluation of the tissue response to the wear products of the hip joint endo-arthroprosthesis.

The causes of tissue reaction surrounding heterogeneous materials are: cell-mediated hypersensitivity due to an implant material; infection; post-surgery hematoma, following lysis of red cells and deposition of hemosiderin; "True" implant reaction, i.e., tissue modifications produced by wear particles of components of the prosthetic devices used. The stages of inflammation due to wear particles are: phagocytosis of particles by newly formed fibrous capsule cells; lymphatic drainage of particles through the newly formed joint capsule; granulation tissue reaction in the internal surface of the joint capsule which stores non-removed particles from inadequate drainage; necrosis of granulation tissue in contacting the artificial joint surface; formation of free masses of necrotic tissue in the joint cavity; formation of new granulation tissue due to these necrotic masses and by wear particles liberated from them (the beginning of a vicious cycle); insufficient storage by granulation tissue; formation of "auxiliary" granulation tissue in the fibrous layer of the bone-cement interfaces and in the R.E.S. of the bone-marrow; bone resorption and its replacement by granulation tissue; loosening of the prosthesis.

Acetabulum↗
PubMed1979

Monitoring adverse drug reactions-the problem of integration of heterogeneous data.

Effective systems for a meaningful integration and interpretation of data of heterogeneous origin are essential for successful monitoring of adverse drug reactions internationally or in multicenter programs. Particular difficulties are encountered in the area of suspected drug adverse reactions and in the area of drugs. Both problem areas are discussed in the paper.

Drug-Related Side Effects and Adverse Reactions↗
PubMed1979

Involvement of host Fc receptors in antibody-mediated cutaneous basophil hypersensitivity reactions.

Cutaneous basophil hypersensitivity (CBH) reactions are heterogeneous delayed time course basophil-rich responses that can be mediated by either T cells, B cells, or serum antibodies. The current study examined the mechanism by which antibodies mediate CBH in guinea pigs. Fc competition experiments were constructed by passively transferring mixtures of anti-KLH serum and normal heterologous gamma-globulins. It was found that rabbit IgG and its isolated and purified Fc fragment [but not the (Fab')2 fragment] inhibited the ability of guinea pig immune serum to transfer CBH. Concurrent inhibition of transferred KLH-specific CBH and systemic passive cutaneous anaphylaxis (PCA) reactions by rabbit IgG or its Fc fragment, and not by sheep or bovine gamma-globulins, indicated that Fc receptors on cutaneous mast cells were probably involved in both CBH and PCA. It was also found that the basophil aspect of delayed cutaneous responses elicited by PHA was inhibited by Fc competition maneuvers. This could mean that some forms of apparently T cell-mediated CBH may be T cell dependent, but via secretion of molecules that bind to Fc receptors, as seems required in antibody-mediated CBH.

Animals↗
PubMed1979

[Role of T- and B-lymphocytes in the heterogeneity of human cell-mediated reactions to bacterial antigens].

Leucocytes from 30 patients with allergy to tuberculin and bacterial antigens were treated with antithymus (ATS) and anti-immune globulin (AIGS) sera. The leucocyte migration inhibition test (LMIT) was performed with these antigens. ATS abolished the LMIT induced by tuberculin and sometimes by bacterial antigens (staphylococcal, streptococcal etc.). AIGS frequently abolished the LMIT induced by bacterial antigens, but not by tuberculin. In some cases the treatment with any serum abolished the LMIT induced by the antigens, or, on the contrary, it was abolished only by a successive treatment with both sera. The lymphocyte types (T or B) determining the secondary immune response to the same antigen are different in various patients, as well as they differ in the same patients in relation to diverse antigens. Five types of lymphocyte - antigen interrelation in the LMIT have been distinguished.

Adult↗
PubMed1976

Quantitative and thermodynamic measurements on I and i antigens of human red blood cells.

Different homogeneous IgM cold agglutinins (two anti-I, two anti-i and one anti-Il cross-reacting antibodies) have been used to determine the antigen site densities of adult I and i erythrocytes and of cord red cells. The equilibirium constants and the thermodynamic constants of these reactions have been determined. The two anti-I antibodies, which did not combine with i or cord red blood cells, recognized two different determinants on I red cells. The antigen density of the I Fla. receptor was 120,000 sites per erythrocyte and the standard enthalpy change (-deltaH degrees) of the reaction was 18 to 25 kcal/mole. The antigen density of the I Loi. determinant varied according to the red cells tested and the enthalpy change (-deltaH degrees) of these reactions was 50-65 kcal/mole. The i and cord erythrocytes reactive structures were more heterogeneous than those present on I erythrocytes. The equilibrium constants rapidly decreased as the temperature rose and the standard enthalpy changes (-deltaH degrees) ranged from 50 to 90 kcal/mole. Two types of i determinants were observed; one of the anti-i antibodies reacted mainly with an i component present on cord erythrocytes, the other antibody reacted with a different i component present on i adult red-cells. The determinants, recognized by the cross -reacting antibody on I red cells, differed fromthose on i or cord red cells in equilibrium constant, thermodynamic constants, index of heterogeneity of the reaction and in their sensitivity to formalin treatment.

Adult↗
PubMed1978

Selective homogenous and heterogeneous catalysis.

Catalysis of organic reactions by micellar aggregates in aqueous solution lacks synthetic utility in its present state, largely for two reasons: first, the selectivity attainable in a loose unstructured micelle is low, with little possibility of attaining the degree of substrate differentiation possible in enzymes, and, second, the scale of reaction is limited, since surfactant must be in large excess over reactant to avoid swamping of the catalytic effect. The discussion will cover initial attempts to overcome these drawbacks. Increased selectivity is apparent in the promotion of ester hydrolysis by micelles of asymmetric chain-functionalized surfactants. In the most favourable circumstances 3:1 discrimination in the rate of reaction of ester enantiomers may be observed. Increased scale of reaction is obtainable when polymer-linked cationic surfactants are used as insoluble catalysts, and these hold promise for various anionactivation reas are used as insoluble catalysts, and these hold promise for varous anion-activation reactions. Specific attention is given to mechanistic aspects of homogenous and heterogeneous catalysis.

Acylation↗
PubMed1975

Nature of photochemical reactions in chromatophores of Chromatium D. III. Heterogeneity of the photosynthetic units.

The effect of isooctane extraction on photooxidation of c-type cytochromes was investigated in Chromatium chromatophores. Photooxidation of cytochrome c-555 was not affected by isooctane-extraction was abolished by thorough extraction of ubiquinone-7, but the quantum yield of the cytochrome photooxidation remained unchanged until 90% of the total ubiquinone was extracted. The photooxidation of cytochrome c-552 was recovered by the addition of ubiquinone-7 but not by menaquinone. A dark incubation of sufficient length was needed for maximal quantum yield of cytochrome c-555 photooxidation in the presence of 30 mM ascorbate. It is proposed that there are two types of photosynthetic units (or associations of molecules involved in the primary redox reactions) in Chromatium chromatophores. The combinations of primary electron donor-reaction center chlorophyll-primary electron acceptor may be cytochrome c-552-P890=ubiquinone in one type and cytochrome c-555-P890-X in another.

Ascorbic Acid↗