Diffusion of Silicon and Manganese in Liquid Iron. I : Diffusion in Liquid Iron Saturated with Carbon

Diffusion coefficients of silicon and manganese in liquid iron (carbon-saturated) were determined in temperature range between 1, 300°and 1, 600°by the method of so-called semi-infinite medium. Blank values accompanied with the measurement of diffusion in liquid state were examined and the following results were obtained : (i) Diffusion coefficients of silicon in Fe-C (saturated)-Si(1.5%) alloys can be expressed as follows : log D (cm^2sec^) = -3.62 - 0.179 × 10^4/T, activation energy Q = 8.2 kcal/g・atom. (ii) Diffusion coefficients of manganese in Fe-C(saturated)-Mn(2.5%) alloys can be expressed as follows : log D (cm^2sec^) = -3.71 - 0.127 × 10^/ T, activation energy Q = 5.8 kcal/g・atom

Elimination of Nitrogen Dissolved in Iron by Addition of Aluminium

When nitrogen gas is reacted on melts of binary Fe-Al alloys under a pressure of one atmosphere, a part of the nitrogen enters the melts, (1) as non-metallic inclusions in the form of AlN compound, while the other part becomes (2) interstitially dissolved nitrogen in its atomic state. We measured the quantity of nitrogen in the two above states separately with respect to samples of Fe-Al alloys of various compositions. In particular, we investigated the relation between the quantity of the interstitially dissolved nitrogen and the aluminium content of the various samples, and arrived at important results suggesting a basic relation in the elimination of nitrogen in iron. melt at variance with the theory accepted hitherto. A statistico-thermodynamical study of the results gave satisfactory answers

Diffusion of Calcium in Liquid Slags

Self-diffusion coefficients of calcium in molten slags (CaO-SiO_2, CaO-Al_2O_3, CaO-SiO_2-Al_2O_3 and CaO-SiO_2-Al_2O_3-MgO systems) were measured by the method of semi-infinite medium in the temperature range from 1350°to 1600℃. The diffusion coefficients were of the order of 10^6～10^7cm^2 sec^ and the activation energies were 40～70kcal/g・mol for all slags investigated. The diffusion coefficient has good correspondence to both the specific electric conductivity and the viscosity coefficient. Some behaviors of Al_2O_3 and MgO in basic slags were also discussed

ACPA-negative RA consists of two genetically distinct subsets based on RF positivity in Japanese.

HLA-DRB1, especially the shared epitope (SE), is strongly associated with rheumatoid arthritis (RA). However, recent studies have shown that SE is at most weakly associated with RA without anti-citrullinated peptide/protein antibody (ACPA). We have recently reported that ACPA-negative RA is associated with specific HLA-DRB1 alleles and diplotypes. Here, we attempted to detect genetically different subsets of ACPA-negative RA by classifying ACPA-negative RA patients into two groups based on their positivity for rheumatoid factor (RF). HLA-DRB1 genotyping data for totally 954 ACPA-negative RA patients and 2,008 healthy individuals in two independent sets were used. HLA-DRB1 allele and diplotype frequencies were compared among the ACPA-negative RF-positive RA patients, ACPA-negative RF-negative RA patients, and controls in each set. Combined results were also analyzed. A similar analysis was performed in 685 ACPA-positive RA patients classified according to their RF positivity. As a result, HLA-DRB1*04:05 and *09:01 showed strong associations with ACPA-negative RF-positive RA in the combined analysis (p = 8.8×10(-6) and 0.0011, OR: 1.57 (1.28-1.91) and 1.37 (1.13-1.65), respectively). We also found that HLA-DR14 and the HLA-DR8 homozygote were associated with ACPA-negative RF-negative RA (p = 0.00022 and 0.00013, OR: 1.52 (1.21-1.89) and 3.08 (1.68-5.64), respectively). These association tendencies were found in each set. On the contrary, we could not detect any significant differences between ACPA-positive RA subsets. As a conclusion, ACPA-negative RA includes two genetically distinct subsets according to RF positivity in Japan, which display different associations with HLA-DRB1. ACPA-negative RF-positive RA is strongly associated with HLA-DRB1*04:05 and *09:01. ACPA-negative RF-negative RA is associated with DR14 and the HLA-DR8 homozygote

Diffusion of Some Alloying Elements in Liquid Iron

The diffusion coefficients of silicon, sulfur and manganese in liquid iron were measured. At low concentrations, the diffusion coefficients of these elements were 2-5×10^cm^2/sec and the activation energies for diffusion were 6-10kcal/mole. With respect to silicon, the variation of diffusivity with the content of silicon were examined up to about 20%. The diffusion coefficient increased with the content of silicon both in pure liquid iron and in carbon-saturated liquid iron. The diffusion coefficients of silicon and sulfur decreased in the presence of carbon. These results were discussed in relation to the thermodynamic property of the liquids

A large-scale association study identified multiple HLA-DRB1 alleles associated with ACPA-negative rheumatoid arthritis in Japanese subjects.

[Background] HLA-DRB1 is associated with rheumatoid arthritis (RA). However, it has recently been suggested that HLA-DRB1 is only associated with patients with RA who have anticitrullinated peptide/protein antibodies (ACPA), which are specific to RA. [Objective] To elucidate whether specific HLA-DR alleles are associated with ACPA-negative RA development. [Methods] HLA-DRB1 typing was carried out in 368 Japanese ACPA-negative patients with RA and 1508 healthy volunteers as the first set, followed by HLA-DRB1 typing of 501 cases and 500 controls as the second set. The HLA-DRB1 allele frequency and diplotype frequency were compared in each group, and the results of the two studies were combined to detect HLA-DRB1 alleles or diplotypes associated with ACPA-negative RA. [Results] HLA-DRB1*12:01 was identified as a novel susceptibility allele for ACPA-negative RA (p=0.000088, OR=1.72, 95% CI 1.31 to 2.26). HLA-DRB1*04:05 and *14:03 showed moderate associations with ACPA-negative RA (p=0.0063, OR=1.26, 95% CI 1.07 to 1.49 and p=0.0043, OR=1.81, 95% CI 1.20 to 2.73, respectively). The shared epitope was weakly associated with ACPA-negative RA, but no dosage effect was detected (p=0.016, OR=1.17, 95% CI 1.03 to 1.34). A combination of HLA-DRB1*12:01 and DRB1*09:01 showed a strong association with susceptibility to ACPA-negative RA (p=0.00013, OR=3.62, 95% CI 1.79 to 7.30). Homozygosity for HLA-DR8 was significantly associated with ACPA-negative RA (p=0.0070, OR=2.16, 95% CI 1.22 to 3.82). It was also found that HLA-DRB1*15:02 and *13:02 were protective against ACPA-negative RA (p=0.00010, OR=0.68, 95% CI 0.56 to 0.83 and p=0.00059, OR=0.66, 95% CI 0.52 to 0.84, respectively). [Conclusions] In this large-scale association study multiple alleles and diplotypes were found to be associated with susceptibility to, or protection against, ACPA-negative RA