Diffusion and activation of n-type dopants in germanium

The diffusion and activation of $n$-type impurities (P and As) implanted into $p$-type Ge(100) substrates were examined under various dose and annealing conditions. The secondary ion mass spectrometry profiles of chemical concentrations indicated the existence of a sufficiently high number of impurities with increasing implanted doses. However, spreading resistance probe profiles of electrical concentrations showed electrical concentration saturation in spite of increasing doses and indicated poor activation of As relative to P in Ge. The relationships between the chemical and electrical concentrations of P in Ge and Si were calculated, taking into account the effect of incomplete ionization. The results indicated that the activation of P was almost the same in Ge and Si. The activation ratios obtained experimentally were similar to the calculated values, implying insufficient degeneration of Ge. The profiles of P in Ge substrates with and without damage generated by Ge ion implantation were compared, and it was clarified that the damage that may compensate the activated $n$-type dopants has no relationship with the activation of P in Ge.Comment: 6 pages, 4 figure

A New Second-order Cone Programming Relaxation for MAX-CUT Problems

We propose a new relaxation scheme for the MAX-CUT problem using second-order cone programming. We construct relaxation problems to reflect the structure of the original graph. Numerical experiments show that our relaxation gives better bounds than those based on the spectral decomposition proposed by Kim and Kojima [16], and that the efficiency of the branch-and-bound method using our relaxation is comparable to that using semidefinite relaxation in some cases

The structural differences between α glycoprotein specific F-box protein Fbs1 and its homologous protein FBG3

The Skp1-Cul1-F-box protein (SCF) complex catalyzes protein ubiquitination in diverse cellular processes and is one of the best-characterized ubiquitin ligases. F-box proteins determine the substrate specificities of SCF ubiquitin ligases. Among these, Fbs1/FBG1/FBXO2, Fbs2/FBG2/FBXO6, and Fbs3/FBG5/FBXO27 recognize the N-glycans of glycoproteins, whereas FBG3/FBXO44 has no sugar-binding activity, despite the high sequence homology and conservation of the residues necessary for oligosaccharide binding between Fbs1.3 and FBG3. Here we determined the crystal structure of the Skp1.FBG3 complex at a resolution of 2.6 A. The substrate-binding domain of FBG3 is composed of a 10-stranded antiparallel β-sandwich with three helices. Although the overall structure of FBG3 is similar to that of Fbs1, the residues that form the Fbs1 carbohydrate-binding pocket failed to be superposed with the corresponding residues of FBG3. Structure-based mutational analysis shows that distinct hydrogen bond networks of four FBG3 loops, i.e., β2-β3, β5-β6, β7-β8, and β9-β10, prevent the formation of the carbohydrate-binding pocket shown in Fbs1

Der f 16: a novel gelsolin-related molecule identified as an allergen from the house dust mite, Dermatophagoides farinae11The sequence data reported in this paper have been deposited in the GenBank sequence database under the accession number AF465625.

AbstractAllergen from the house dust mite (Dermatophagoides sp.) is a major trigger factor of allergic disorders, and its characterization is crucial for the development of specific diagnosis or immunotherapy. Here we report the identification of a novel dust mite (Dermatophagoides farinae) antigen whose primary structure belongs to the gelsolin family, a group of actin cytoskeleton-regulatory proteins. Isolated mite cDNA, termed Der f 16, encodes 480 amino acids comprising a four-repeated gelsolin-like segmental structure, which is not seen in conventional gelsolin family members. Enzyme immunoassay indicated that recombinant Der f 16 protein, prepared using an Escherichia coli expression system, bound IgE from mite-allergic patients at 47% (8/17) frequency. This is the first evidence that the gelsolin family represents a new class of allergen recognizable by atopic patient IgE

Purification and characterization of M-177, a 177 kDa allergen, from the house dust mite Dermatophagoides farinae

A high molecular weight allergen, M-177, was recently discovered in the house dust mite, Dermatophagoides farinae (D. farinae). The aims of this study were to develop a conventional purification procedure for M-177 and then to analyze some of the immunochemical properties of M-177. Mite extracts obtained from purified mite bodies were a suitable material for preparing M-177, because the purified mite extract contained large amounts of M-177. The purification of this allergen from the extract was achieved by ethanol fractionation, anion exchange chromatography, and gel filtration chromatography. The purified antigen was immunochemically equivalent to that of a preparation obtained by a previous affinity method using an anti-Mag 3-immobilized column. The yield of this purification procedure was 36.8% of the initial amount of M-177 in the extract, 40-fold greater than that of the previous immunoaffinity method. Our purification method was useful for preparing this allergen. The purified M-177 reacted in skin tests in 11 of 16 miteallergic patients, compared to 10 of 16 with Der f 2. The amount of M-177 in the purified mite extract determined by enzyme-linked immunosorbent assay inhibition was as much as 0.95% of the total protein, which was higher than the amounts of Der f 1 (0.52%) and Der f 2 (0.32%). The potent allergenic activity and large amount of M-177 in the mites indicate that it is an important mite allergen