ABSTRACT
This paper examines the effectiveness of the method for producing synthetic rutile from ilmenite through pre-oxidation and reductive leaching of pre-oxidized ilmenite in hydrochloric acid. Thermodynamic simulation of the pre-oxidation of ilmenite concentrate was performed to evaluate the phases formed during the process as a function of temperature. The pre-oxidation experiments were performed at different temperatures between 700 and 1000 °C in a muffle furnace for 6 h. The optimum temperature of pre-oxidation was revealed to be at 700 °C where ilmenite transformed into hematite and rutile, which is in accordance with the result of the thermodynamic simulation. Series of the leaching experiments were carried out under variations of HCl concentration (5-8 M), leaching temperature (70-100 °C), solid/liquid ratio (1/5-1/20 g/mL), ilmenite ore particle size distribution, and duration of leaching (6-12 h). Taguchi method utilizing L16 orthogonal array was adopted in the leaching step to design and reduce the required number of experiments. Analysis of variance (ANOVA) indicated that the temperature and solid/liquid (S/L) ratio were the most influential leaching parameters for the dissolution of iron and titanium. The optimum conditions for maximising the dissolution of iron, while minimizing the dissolution of titanium were at a temperature of 80 °C, HCl of 6 M, S/L ratio of 1/20 g/mL, ore particle size distribution of 44-77 µm (-200 + 325 mesh), and leaching duration of 6 h. The leaching experiment conducted under these conditions resulted in iron extraction of 98.07% with co-extraction of titanium of 11.35%. The leach-residue contains 92.6% rutile, 2.9% hematite, and 2.5% cassiterite which can be classified as synthetic grade rutile.
ABSTRACT
Studies on mucosal-associated invariant T cells (MAITs) in nonhuman primates (NHP), a physiologically relevant model of human immunity, are handicapped due to a lack of macaque MAIT-specific reagents. Here we show that while MR1 ligand-contact residues are conserved between human and multiple NHP species, three T-cell receptor contact-residue mutations in NHP MR1 diminish binding of human MR1 tetramers to macaque MAITs. Construction of naturally loaded macaque MR1 tetramers facilitated identification and characterization of macaque MR1-binding ligands and MAITs, both of which mirrored their human counterparts. Using the macaque MR1 tetramer we show that NHP MAITs activated in vivo in response to both Bacillus Calmette-Guerin vaccination and Mycobacterium tuberculosis infection. These results demonstrate that NHP and human MR1 and MAITs function analogously, and establish a preclinical animal model to test MAIT-targeted vaccines and therapeutics for human infectious and autoimmune disease.
Subject(s)
Histocompatibility Antigens Class I/metabolism , Minor Histocompatibility Antigens/metabolism , Mucosal-Associated Invariant T Cells/immunology , Mycobacterium tuberculosis/immunology , T-Lymphocytes/immunology , Tuberculosis Vaccines/immunology , Tuberculosis/immunology , Animals , Cells, Cultured , Disease Models, Animal , Histocompatibility Antigens Class I/genetics , Humans , Macaca mulatta , Minor Histocompatibility Antigens/genetics , Protein Binding , Protein Engineering , Receptors, Antigen, T-Cell/metabolism , Sequence Alignment , Species Specificity , VaccinationABSTRACT
AIM: to identify the prevalence of laboratoric ASA resistance using platelet function tests in patients with ischemic stroke at Cipto Mangunkusumo Hospital and its associated factors. METHODS: this study was a cross-sectional study involving 50 patients with ischemic stroke who only received ASA treatment. Evaluation of resistance to ASA was performed using Verifynow® platelet function test. ASA resistance was defined as ASA reaction unit (ARU) 550. RESULTS: there were 7 patients with ASA resistance. The mean age of subjects in ASA resistance group was 51.3±9.2 years; while in ASA responsive group was 57.8±9.7 years. In ASA resistance group, there were 85.7% male patients, 57.1% active smoker and 100% subjects with hypertension. CONCLUSION: the prevalence of laboratoric ASA resistance in patients with ischemic stroke evaluated using platelet function test at Cipto Mangunkusumo Hospital is 14%. The prevalence is more likely to occur in male patients who were active smoker, at younger age and with comorbidity of hypertension.
