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The effect of environmental humidity on the self-lubricating properties of a thin film of boric acid (H3BO3) was evaluated. H3BO4 films were successfully formed on the surface of AISI 316L steel. The study was conducted on AISI 316L steel because of its use in biomedical applications. First, the samples were exposed to boriding to generate a continuous surface layer of iron borides. The samples were then exposed to a short annealing process (SAP) at 1023 K for 5 min and cooled to room temperature while controlling the relative humidity (RH). Five different RH conditions were tested. The purpose of SAP was to promote the formation of a surface film of boric acid from the boron atoms present in the iron boride layers. The presence of the boric acid at the surface of the borided layer was confirmed by Raman spectroscopy and X-ray diffraction (XRD). The self-lubricating capability of the films was demonstrated using the pin-on-disk technique. The influence of RH was reflected by the friction coefficient (FC), as the samples cooled with 20% of RH exhibited FC values of 0.16, whereas the samples cooled at 60% RH showed FC values of 0.02. [ABSTRACT FROM AUTHOR]

Abstract: Ferromagnetism is observed in LiNiO3 nanocrystals exposed to a reducing atmosphere intended to create oxygen vacancies. The existence of vacancies is confirmed by measuring the oxygen depletion across the selected nanoparticles by TEM. The magnetism shows no temperature dependence in the range of 4–300K. The density functional theory was used to perform spin polarized electronic structure calculations for LiNiO3 with and without oxygen vacancies. The calculated magnetic data qualitatively support the observed magnetic behavior. [Copyright &y& Elsevier]

Examines the effect of co-stimulatory signals on the reactivity of gamma delta T cells to mycobacterial antigens. Enhancement of gamma delta T cells reactivity; Association of tuberculosis with HIV infection; Role of interleukin-10 in gamma delta T cell proliferation.

In Mycobacterium tuberculosis culture filtrates, three concanavalin A (ConA)-binding bands of 55, 50 and 38 kilodaltons (kD) were identified by labelling blotted proteins with a ConA-peroxidase conjugate. Binding was inhibited by the competitor sugar a-methylmannoside and by reduction with sodium m-periodate. Bands of 55, 50 and 38 kD stained with Coomasie blue were sensitive to digestion with proteases, thus indicating that they are proteins. Glycoproteins were isolated by lectin affinity chromatography or by elution from nitrocellulose membranes. On the isolated form, the 55-50 kD doublet glycoprotein was 65.4% protein and 34.6% sugar. The purified 38 kD molecule was 74.3% protein and 25.7% carbohydrate. By immunoblot, antibodies against mycobacterial glycoproteins were demonstrated in immunized rabbits and in patients with pulmonary tuberculosis, but not in healthy individuals. Treatment with sodium m-periodate abolished binding of rabbit antibodies to the 38 kD glycoprotein. Reactivity of the 55-50 kD doublet glycoprotein was not altered by reduction. By immunoblot with monoclonal antibodies TB7I and TB72. a carbohydratedependent and a carbohydrate-independent epitope could be identified on the 38 kD glycoprotein. [ABSTRACT FROM AUTHOR]

We induced lung granulomas in BALB/c mice by intratracheal instillation of Sepharose beads coated with a Mycobacterium tuberculosis protein extract. Granulomas composed of macrophages and lymphocytes were induced. The granulomatous reaction reached its peak 3-7 days after challenge and lasted for approximately 1 month. Immunolabelling of tissue sections and bronchial washings revealed that granulomas were predominantly composed of T lymphocytes with the cytotoxic-suppressor phenotype (CD8+). Oranulomas were associated with a significant decrease in anti-mycobacterial immunity manifested by a drop in delayed-type hypersensitivity reactions and antibody titres. The immunosuppressive phenomena were abolished with cyclophosphamide or indomethacin. Control granulomas induced with methylated bovine serum albumin (BSA) were smaller and composed by similar numbers of CD4+ and CD8+ cells. BSA granulomas did not alter antibody titres but they decreased delayed-type hypersensitivity to BSA which was restored to normal with indomethacin but not with cyclophosphamide. Our findings show that mycobacterial proteins anchored to Sepharose beads are granulomatogenic and that they preferentially recruit CD8+ cells which, together with locally produced prostaglandins, down-modulate cell-mediated and humoral immunity to mycobacterial antigens. [ABSTRACT FROM AUTHOR]

Immunobiot assays showed that mycobacierial fibronectin-binding antigens are important targets of the humoral immune response in tuberculosis and leprosy. Using culture filtrate antigens of Mycobaeterium tuberculosis, strong reactivity with the fibronectin-binding of 30-31 kD (Fn 30-31) was demonstrated in 55.9% of tuberculosis sera and in 56.5% of lepromatous leprosy sera. Sera from patients with tuberculoid leprosy and control sera gave very weak binding. Reactivity of tuberculosis and lepromatous leprosy sera with the fibronectin-binding antigen of 58-60 kD (Fn 58-60) was less conspicuous. The ability to react with fibronectin of the antigens of 58-60 and 30-31 kD was demonstrated by parallel labelling with a fibronectin biotin conjugate. Fn 30-31 was purified to homogeneity by a two-step procedure and used for ELISA. Positive titres were found in 63% out of 65 tuberculosis sera and in 60.5% out of 43 lepromatous leprosy sera. Antibody titres in lepromatous leprosy sera were higher than in tuberculosis sera. Our observations indicate indirectly that M. leprae possess a highly immunogenic molecule homologous to M. tuberculosis Fn 30-31, which elicits a high antibody response in lepromatous leprosy but not in tubereuloid leprosy. In this investigation, direct evidence for the presence of this antigen in M. leprae was obtained by immunochemistry of lepromatous leprosy lesions with a monospecific antibody raised against M. tuberculosis Fn 30-31. [ABSTRACT FROM AUTHOR]

To identify antigens that could be specifically associated with tuberculosis infection, the antibody response to Mycobacterium tuberculosis antigens of patients with pulmonary tuberculosis and of healthy individuals were compared by immunoblot. In healthy individuals, scrum antibodies were found in the majority of cases. Bands of 60 and 32-31 kilodaltons (kD) were the antigens more frequently recognized by antibodies of normal sera (55.8 and 64.7%, respectively). In patients with pulmonary tuberculosis, the number and intensity of the developed antigen bands were much higher than in normal individuals. Antigens reacting preferentially with tuberculosis sera were also identified. Furthermore, a unique disease-associated protein antigen or 38 kD was found to react with 57% of patients' sera but with none of the controls. This antigen was isolated by elution from nitrocellulose membranes and tested as an ELISA reagent in the serodiagnosis of pulmonary tuberculosis. A specificity of 0.96 and sensitivity of 0.68 were obtained. [ABSTRACT FROM AUTHOR]