Reduction of In Composition in Heavily Zn-Doped InAlGaAs Layers Grown at Low Temperature by Metalorganic Chemical Vapor Deposition

Growth of heavily Zn-doped InAlGaAs at low temperature (560 C) by metalorganic chemical vapor deposition (MOCVD) is investigated. The lattice constant contracts and the growth rate decreases with increasing dithylzinc (DEZn) flow rate. To clarify the reason, the growth rates of InAs, AlAs, and GaAs components are examined. The growth rates of AlAs and GaAs components are almost constant; only that of InAs dramatically decreases when the DEZn flow increases. This indicates that the incorporation of In is suppressed by the DEZn supply. The doping behavior during the growth is well fit by the surface adsorption-trapping model, which suggests that excess Zn atoms on the growth surface induce the reduction of the InAs component.

Characteristics of InP/InGaAs HPT-based Optically Injection-Locked Self-oscillating Optoelectronic Mixers and Their Influence on RoF System Performance

Abstract A 30GHz optically injection-locked self-oscillating optoelectronic mixer (OIL-SOM) is implemented with a high-performance InP/InGaAs heterojunction phototransistor. The sub-harmonic conversion efficiency and phase noise characteristics of OIL-SOM are investigated and used for analyzing OIL-SOM-based 60GHz radio-on-fiber downlink data transmission performance. The OIL-SOM characteristics provide lower and upper boundaries for the input optical LO power range within which the link performance does not significantly depend on input optical LO power. Index Terms: heterojunction phototransistor (HPT), optically injection-locked selfoscillating optoelectronic mixer (OIL-SOM), phase noise, conversion efficiency, 60GHz, radio-on-fiber system, optical LO power

Identification of Disease-Promoting HLA Class I and Protective Class II Modifiers in Japanese Patients with Familial Mediterranean Fever

Objectives: The genotype-phenotype correlation of MEFV remains unclear for the familial Mediterranean fever (FMF) patients, especially without canonical MEFV mutations in exon 10. The risk of FMF appeared to be under the influence of other factors in this case. The contribution of HLA polymorphisms to the risk of FMF was examined as strong candidates of modifier genes. Methods: Genotypes of HLA-B and -DRB1 loci were determined for 258 mutually unrelated Japanese FMF patients, who satisfied modified Tel-Hashomer criteria, and 299 healthy controls. The effects of carrier status were evaluated for the risk of FMF by odds ratio (OR). The HLA effects were also assessed for clinical forms of FMF, subsets of FMF with certain MEFV genotypes and responsiveness to colchicine treatment. Results: The carriers of B?39:01 were increased in the patients (OR = 3.25, p = 0.0012), whereas those of DRB1?15:02 were decreased (OR = 0.45, p = 0.00050), satisfying Bonferroni\u27s correction for multiple statistical tests (n = 28, p<0.00179). The protective effect of DRB1?15:02 was completely disappeared in the co-existence of B?40:01. The HLA effects were generally augmented in the patients without a canonical MEFV variant allele M694I, in accordance with the notion that the lower penetrance of the mutations is owing to the larger contribution of modifier genes in the pathogenesis, with a few exceptions. Further, 42.9% of 14 colchicine-resistant patients and 13.5% of 156 colchicine-responders possessed B?35:01 allele, giving OR of 4.82 (p = 0.0041). Conclusions: The differential effects of HLA class I and class II polymorphisms were identified for Japanese FMF even in those with high-penetrance MEFV mutations

The Contribution of SAA1 Polymorphisms to Familial Mediterranean Fever Susceptibility in the Japanese Population

Background/Aims: Familial Mediterranean Fever (FMF) has traditionally been considered to be an autosomal-recessive disease, however, it has been observed that substantial numbers of patients with FMF possess only 1 demonstrable MEFV mutation. The clinical profile of familial Mediterranean fever (FMF) may be influenced by MEFV allelic heterogeneity and other genetic and/or environmental factors. Methodology/Principal Findings: In view of the inflammatory nature of FMF, we investigated whether serum amyloid A (SAA) and interleukin-1 beta (IL-1β) gene polymorphisms may affect the susceptibility of Japanese patients with FMF. The genotypes of the -13C/T SNP in the 5′-flanking region of the SAA1 gene and the two SNPs within exon 3 of SAA1 (2995C/T and 3010C/T polymorphisms) were determined in 83 Japanese patients with FMF and 200 healthy controls. The same samples were genotyped for IL-1β-511 (C/T) and IL-1 receptor antagonist (IL-1Ra) variable number of tandem repeat (VNTR) polymorphisms. There were no significant differences between FMF patients and healthy subjects in the genotypic distribution of IL-1β -511 (C/T), IL-1Ra VNTR and SAA2 polymorphisms. The frequencies of SAA1.1 allele were significantly lower (21.7% versus 34.0%), and inversely the frequencies of SAA1.3 allele were higher (48.8% versus 37.5%) in FMF patients compared with healthy subjects. The frequency of -13T alleles, associated with the SAA1.3 allele in the Japanese population, was significantly higher (56.0% versus 41.0%, p = 0.001) in FMF patients compared with healthy subjects. Conclusions/Significance: Our data indicate that SAA1 gene polymorphisms, consisting of -13T/C SNP in the 5′-flanking region and SNPs within exon 3 (2995C/T and 3010C/T polymorphisms) of SAA1 gene, are associated with susceptibility to FMF in the Japanese population