Superluminescent diode with a broadband gain based on self-assembled InAs quantum dots and segmented contacts for an optical coherence tomography light source

We report a broadband-gain superluminescent diode (SLD) based on self-assembled InAs quantum dots (QDs) for application in a high-resolution optical coherence tomography (OCT) light source. Four InAs QD layers, with sequentially shifted emission wavelengths achieved by varying the thickness of the In0.2Ga0.8As strain-reducing capping layers, were embedded in a conventional p-n heterojunction comprising GaAs and AlGaAs layers. A ridge-type waveguide with segmented contacts was formed on the grown wafer, and an as-cleaved 4-mm-long chip (QD-SLD) was prepared. The segmented contacts were effective in applying a high injection current density to the QDs and obtaining emission from excited states of the QDs, resulting in an extension of the bandwidth of the electroluminescence spectrum. In addition, gain spectra deduced with the segmented contacts indicated a broadband smooth positive gain region spanning 160 nm. Furthermore, OCT imaging with the fabricated QD-SLD was performed, and OCT images with an axial resolution of ∼4 μm in air were obtained. These results demonstrate the effectiveness of the QD-SLD with segmented contacts as a high-resolution OCT light source

Discovery of Genes Activated by the Mitochondrial Unfolded Protein Response (mtUPR) and Cognate Promoter Elements

In an accompanying paper, we show that the mitochondrial Unfolded Protein Response or mtUPR is initiated by the activation of transcription of chop through an AP-1 element in the chop promoter. Further, we show that the c/ebpβ gene is similarly activated and CHOP and C/EBPβ subsequently hetero-dimerise to activate transcription of mtUPR responsive genes. Here, we report the discovery of six additional mtUPR responsive genes. We found that these genes encoding mitochondrial proteases YME1L1 and MPPβ, import component Tim17A and enzymes NDUFB2, endonuclease G and thioredoxin 2, all contain a CHOP element in their promoters. In contrast, genes encoding mitochondrial proteins Afg3L2, Paraplegin, Lon and SAM 50, which do not have a CHOP element, were not up-regulated. Conversely, genes with CHOP elements encoding cytosolic proteins were not induced by the accumulation of unfolded proteins in mitochondria. These results indicate that mtUPR responsive genes appear to share a requirement for a CHOP element, but that this is not sufficient for the regulation of the mtUPR. A more detailed analysis of promoters of mtUPR responsive genes revealed at least two additional highly conserved, putative regulatory sites either side of the CHOP element, one a motif of 12 bp which lies 14 bp upstream of the CHOP site and another 9 bp element, 2 bp downstream of the CHOP site. Both of these additional elements are conserved in the promoters of 9 of the ten mtUPR responsive genes we have identified so far, the exception being the Cpn60/10 bidirectional promoter. Mutation of each of these elements substantially reduced the mtUPR responsiveness of the promoters suggesting that these elements coordinately regulate mtUPR

Gastric cancer screening by combined assay for serum anti-Helicobacter pylori IgG antibody and serum pepsinogen levels — “ABC method”

The current status of screening for gastric cancer-risk (gastritis A, B, C, D) method using combined assay for serum anti-Helicobacter pylori (Hp) IgG antibody and serum pepsinogen (PG) levels, “ABC method”, was reviewed and the latest results of our ongoing trial are reported. It was performed using the following strategy: Subjects were classified into 1 of 4 risk groups based on the results of the two serologic tests, anti-Hp IgG antibody titers and the PG I and II levels: Group A [Hp(−)PG(−)], infection-free subjects; Group B [Hp(+)PG(−)], chronic atrophic gastritis (CAG) free or mild; Group C [Hp(+)PG(+)], CAG; Group D [Hp(−)PG(+)]), severe CAG with extensive intestinal metaplasia. Continuous endoscopic follow-up examinations are required to detect early stages of gastric cancer. Asymptomatic Group A, which accounts for 50–80% of all the subjects may be excluded from the secondary endoscopic examination, from the viewpoint of efficiency. Hp-infected subjects should be administered eradication treatment aimed at the prevention of gastric cancer

Biological detoxification of the mycotoxin deoxynivalenol and its use in genetically engineered crops and feed additives

Deoxynivalenol (DON) is the major mycotoxin produced by Fusarium fungi in grains. Food and feed contaminated with DON pose a health risk to humans and livestock. The risk can be reduced by enzymatic detoxification. Complete mineralization of DON by microbial cultures has rarely been observed and the activities turned out to be unstable. The detoxification of DON by reactions targeting its epoxide group or hydroxyl on carbon 3 is more feasible. Microbial strains that de-epoxidize DON under anaerobic conditions have been isolated from animal digestive system. Feed additives claimed to de-epoxidize trichothecenes enzymatically are on the market but their efficacy has been disputed. A new detoxification pathway leading to 3-oxo-DON and 3-epi-DON was discovered in taxonomically unrelated soil bacteria from three continents; the enzymes involved remain to be identified. Arabidopsis, tobacco, wheat, barley, and rice were engineered to acetylate DON on carbon 3. In wheat expressing DON acetylation activity, the increase in resistance against Fusarium head blight was only moderate. The Tri101 gene from Fusarium sporotrichioides was used; Fusarium graminearum enzyme which possesses higher activity towards DON would presumably be a better choice. Glycosylation of trichothecenes occurs in plants, contributing to the resistance of wheat to F. graminearum infection. Marker-assisted selection based on the trichothecene-3-O-glucosyltransferase gene can be used in breeding for resistance. Fungal acetyltransferases and plant glucosyltransferases targeting carbon 3 of trichothecenes remain promising candidates for engineering resistance against Fusarium head blight. Bacterial enzymes catalyzing oxidation, epimerization, and less likely de-epoxidation of DON may extend this list in future

エレクトロセラミックスに於ける応用鉱物学の実践―マイクロ波/ミリ波誘電体を例に = Practicing applied mineralogy on the electroceramics:examples: microwave and millimeter-wave dielectrics

Abstract The author and his coleage have been studying electroceramics based on the applied mineralogy. The mineralogy has long history and has been the origin of all science. The material science is also based on the mineralogy. The author studied crystal structure analysis at the Mineralogical School of the University of Tokyo, and material science at the Department of Ceramics of Nagoya Institute of Technology, so he applied mineralogy to material science. He has been studying in following area: microwave dielectrics, millimeter-wave dielectrics, multilayer ceramic condenser, piezoelectric materials and so on. In this paper, pseudo-tungstenbronze dielectrics and homologous compound series on the microwave dielectrics and indialite/cordierite glass ceramics on the millimeter-wave dielectrics has been reviewed. The pseudo-tungstenbronze solid solutions have special point of x = 2/3 on the Ba₆₋₃xR₈+₂ₓTi₁₈O₅₄ (R = rare earth) that is the compositional ordering performed high quality factor based on the relationship between crystal structure and properties. Based on the knowledge of high Qf due to compositional ordering, new dielectrics with high Qf had been designed. On the homologous compounds, the relationship between the Qf properties and crystal structure due to substitute large cataion has been clarified for the design of base station resonator. On the millimeter-wave dielectrics, indialite glass ceramics are presented, which has low dielectric constant of 4.7 and extremely high Qf of more than 200 × 10³ GHz. It will be applied for resonators, patch antennas and LTCC substrates. The other materials such as multilayer capacitors and piezoelectric materials will be reviewed near future.抄録 The author and his coleage have been studying electroceramics based on the applied mineralogy. The mineralogy has long history and has been the origin of all science. The material science is also based on the mineralogy. The author studied crystal structure analysis at the Mineralogical School of the University of Tokyo, and material science at the Department of Ceramics of Nagoya Institute of Technology, so he applied mineralogy to material science. He has been studying in following area: microwave dielectrics, millimeter-wave dielectrics, multilayer ceramic condenser, piezoelectric materials and so on. In this paper, pseudo-tungstenbronze dielectrics and homologous compound series on the microwave dielectrics and indialite/cordierite glass ceramics on the millimeter-wave dielectrics has been reviewed. The pseudo-tungstenbronze solid solutions have special point of x = 2/3 on the Ba₆₋₃xR₈+₂ₓTi₁₈O₅₄ (R = rare earth) that is the compositional ordering performed high quality factor based on the relationship between crystal structure and properties. Based on the knowledge of high Qf due to compositional ordering, new dielectrics with high Qf had been designed. On the homologous compounds, the relationship between the Qf properties and crystal structure due to substitute large cataion has been clarified for the design of base station resonator. On the millimeter-wave dielectrics, indialite glass ceramics are presented, which has low dielectric constant of 4.7 and extremely high Qf of more than 200 × 10³ GHz. It will be applied for resonators, patch antennas and LTCC substrates. The other materials such as multilayer capacitors and piezoelectric materials will be reviewed near future