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21.
Eiji Hayase Takehiko Shibata Tadahiko Ando 《Biochemical and biophysical research communications》1975,62(4):849-855
An enzyme activity specific for UV-DNA1 was found in the extract of (Marburg 168). The enzyme preparation obtained from the extract by ammonium sulfate precipitation acts on UV-DNA endonucleolytically and induces single strand breaks. The number of single strand breaks introduced in DNA is proportional to UV dose. 相似文献
22.
Yoshinori Funama Yoshiaki Sugaya Osamu Miyazaki Daisuke Utsunomiya Yasuyuki Yamashita Kazuo Awai 《Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB)》2013,29(1):39-47
PurposeTo develop a new automatic exposure control (AEC) technique based on the contrast-to-noise ratio (CNR) and provide constant lesion detectability.MethodsLesion detectability is affected by factors such as image noise, lesion contrast, and lesion size. We performed ROC analysis to assess the relationship between the optimum CNR and the lesion diameter at various levels of lesion contrast. We then developed a CNR-based AEC algorithm based on lesion detectability. Using CNR- based AEC algorithm, we performed visual evaluation of low-contrast detectability by 5 radiologists on a low-contrast module of the Catphan phantom, a contrast-difference level of 1.0% (difference in the CT number = 10 HU), and objects 3.0–9.0 mm in diameter.ResultsOn step-and-shoot scans the mean detection fraction with CNR-based AEC remained almost constant from 88 to 99 % regardless of the lesion size. We observed the same trend on helical scans, the mean detection fraction with CNR-based AEC exhibited a high score from 91 to 100%. Although CNR-based AEC maintains higher CNR for smaller size or lower contrast lesion, radiation dose on 3 mm lesion resulted in about 13 times larger than that of 9 mm lesion size. CTDIvol for the CNR-based AEC technique changed dramatically with the SDZ from 7.5 to 100.0 mGy for step-and-shoot scans and from 9.1 to 121.5 mGy for helical scans.ConclusionsFrom the viewpoint of ROC analysis-based CNR for lesion detection, CNR-based AEC potentially provide image quality advantages for clinical implementation. 相似文献
23.
Sheila Unger Maria?W. Górna Antony Le?Béchec Sonia Do?Vale-Pereira Maria?Francesca Bedeschi Stefan Geiberger Giedre Grigelioniene Eva Horemuzova Faustina Lalatta Ekkehart Lausch Cinzia Magnani Sheela Nampoothiri Gen Nishimura Duccio Petrella Francisca Rojas-Ringeling Akari Utsunomiya Bernhard Zabel Sylvain Pradervand Keith Harshman Belinda Campos-Xavier Luisa Bonafé Giulio Superti-Furga Brian Stevenson Andrea Superti-Furga 《American journal of human genetics》2013,92(6):990-995
Kenny-Caffey syndrome (KCS) and the similar but more severe osteocraniostenosis (OCS) are genetic conditions characterized by impaired skeletal development with small and dense bones, short stature, and primary hypoparathyroidism with hypocalcemia. We studied five individuals with KCS and five with OCS and found that all of them had heterozygous mutations in FAM111A. One mutation was identified in four unrelated individuals with KCS, and another one was identified in two unrelated individuals with OCS; all occurred de novo. Thus, OCS and KCS are allelic disorders of different severity. FAM111A codes for a 611 amino acid protein with homology to trypsin-like peptidases. Although FAM111A has been found to bind to the large T-antigen of SV40 and restrict viral replication, its native function is unknown. Molecular modeling of FAM111A shows that residues affected by KCS and OCS mutations do not map close to the active site but are clustered on a segment of the protein and are at, or close to, its outer surface, suggesting that the pathogenesis involves the interaction with as yet unidentified partner proteins rather than impaired catalysis. FAM111A appears to be crucial to a pathway that governs parathyroid hormone production, calcium homeostasis, and skeletal development and growth. 相似文献
24.
An alkaline proteinase of Aspergillus Candidus was purified from wheat bran solid culture by batchwise treatment with Amberlite IRC–50 and sequential chromatography on DEAE-cellulose, hydroxylapatite and Sephadex G–100 gel. This purification results in a 18-fold increase of proteolytic activity and the enzyme preparation was homogeneous in sedimentation analysis of the ultracentrifuge and polyacrylamide gel disc electrophoresis. The molecular weight was estimated to be about 23,000 by gel glltration and 22,000 by calculation from the amino acid composition. The enzyme consisted of Lys14, His4, Arg3, Asp25, Thr15, Ser23, Glu15, Pro7, Gly22, Ala24, Met2, Val16, Ile11, Leu10, Tyr6, Phe7, Trp2 and amide ammonia14 and did not contain cysteine or cystine. 相似文献
25.
Some enzymatic properties were examined with the purified alkaline proteinase from Aspergillus candidus. The isoelectric point was determined to be 4.9 by polyacrylamide gel disc electrofocusing. The optimum pH for milk casein was around 11.0 to 11.5 at 30°C. The maximum activity was found at 47°C at pH 7.0 for 10 min. The enzyme was stable between pH 5.0 and 9.0 at 30°C and most stable at pH 6.0 at 50°C. The enzyme activity over 95% remained at 40°C, but was almost completely lost at 60°C for 10 min. Calcium ions protected the enzyme from heat denaturation to some extent. No metal ions examined showed stimulatory effect and Hg2+ ions inhibited the enzyme. The enzyme was also inhibited by potato inhibitor and diisopropylphosphorofluoridate, but not by metal chelating agent or sulfhydryl reagents. A. candidus alkaline proteinase exhibited immunological cross-reacting properties similar to those of alkaline proteinases of A. sojae and A. oryzae. 相似文献
26.
Akikazu Hatanaka Tadahiko Kajiwara Takatoshi Koda 《Bioscience, biotechnology, and biochemistry》2013,77(10):2115-2117
The substrate specificity of enzyme system producing C6-aldehyde in Thea chloroplasts was clarified with an entire series of synthesized positional isomers, in which the position of cis-1, cis-4-pentadiene system varies from C-3 to C-13 in C18 fatty acid and geometrical isomers of linoleic acid. The structural requirement for the substrate of enzyme system producing C6-aldehyde is the presence of cis-1, cis-4-pentadiene system between ω-6 and ω-10. 相似文献
27.
The oxidation of methionine to its sulfoxide, as a possible cause of decrease in the biological value of red clover during drying with aeration, was examined using various model systems, in the presence or absence of polyphenol oxidase. The effects of catalase were also examined. Results indicated hydrogen peroxide as a possible intermediate that directly oxidizes methionine. The methionine oxidation can be one of the causes of the decrease in biological value of red clover during drying, beside the known damage of lysine in the same process. 相似文献
28.
Seiichi Nasuno Tadahiko Ohara Nobuyoshi Iguchi 《Bioscience, biotechnology, and biochemistry》2013,77(2):291-293
Hydrochloric acid treatment of methyl 3-(4-isobutylphenyl)-3-methylglycidate and methyl 2-hydroxy-3-(4-isobutylphenyl)-3-butenoate, a rearrangement product of the former, in acetic acid gave 3-(4-isobutylphenyl)-3-methylpyruvic acid and 2-(4-isobutylphenyl)-pro-panal. The same treatment of 2-hydroxy-3-(4-isobutylphenyl)-3-butenoic acid gave 2-(4-isobutylphenyl)-propanal. Both 3-(4-isobutylphenyl)-3-methylpyruvic acid and 2-(4-iso-butylphenyl)-propanal were oxidized to 2-(4-isobutylphenyl)-propionic acid. 相似文献
29.
Jiro Sekiya Tadahiko Kajiwara Akikazu Hatanaka 《Bioscience, biotechnology, and biochemistry》2013,77(3):677-678
A simple electronic device was constructed which, in combination with a conventional titrator, records close approximation of the buffer capacity curve (β-pH curve) for the solution of unknown composition. Since the recorded curves provide the overall picture of the distribution of weak Brönsted acids in the solution on the pKa axis, this apparatus may be useful in various fields such as chemistry of food and agricultural products and clinical medicine, where the characterization of the complex mixtures of weak electrolytes — carboxylic acids, amono acids, proteins, amines, phenols and etc. — are important. 相似文献
30.
Jiro Sekiya Wataru Kawasaki Tadahiko Kajiwara Akikazu Hatanaka 《Bioscience, biotechnology, and biochemistry》2013,77(8):1677-1678
d-Coronamic acid was deaminated by 1-aminocyclopropane-1-carboxylate (ACPC) deaminase to produce α-keto-n-caproic acid. This deaminase which was purified from Pseudomonas sp. ACP was active to only d-coronamic acid among its stereoisomers. l-Coronamic acid or dl-allocoronamic acid was inactive or negligibly poor as the substrate. In addition, both deamination of ACPC and d-coronamic acid were inhibited by l-alanine, not by d-isomer and the inhibition of ACPC deamination by l-alanine was competitive. On the basis of these results, stereoselectivity of the enzymatic deamination was discussed. 相似文献