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971.
Trevor Hastie Debra Ikeda Robert Tibshirani 《Journal of computational and graphical statistics》2013,22(3):531-543
Abstract We propose statistical measures for finding masses in mammograms. The measures are based on fitting broken line regressions to local intensity plots of the images. The method is illustrated on a small database of mammograms that have been read by a radiologist and confirmed by operative data. This work illustrates some of the statistical challenges in working with large diagnostic images 相似文献
972.
Kazuhide Yamashita Takeshi Fukushima Tsukasa Sasaki Kotaro Arai Toshimasa Toyo'oka 《Biomedical chromatography : BMC》2009,23(8):793-797
Enantiomeric separation of d ‐ and l ‐serine on an octadecylsilica column was investigated using (2R)‐2,5‐dioxopyrrolidin‐1‐yl‐2,5,7,8‐tetramethyl‐6‐(tetrahydro‐2H‐pyran‐2‐yloxy)chroman‐2‐carboxylate (R‐NPCA), which was developed for a pre‐column derivatization reagent for electrochemical detection. In addition, (2S)‐2,5‐dioxopyrrolidin‐1‐yl‐2,5,7,8‐tetramethyl‐6‐(tetrahydro‐2H‐pyran‐2‐yloxy)chroman‐2‐carboxylate (S‐NPCA) was newly synthesized from (S)‐(?)‐6‐hydroxy‐2,5,7,8‐tetramethylchroman‐2‐carboxylic acid (S‐α‐CA), and the enantiomeric separation of d ‐ and l ‐serine using S‐NPCA was also examined. The enantiomeric separation of d ,l ‐serine was achieved using the R‐ or S‐NPCA as a chiral derivatization reagent, and the elution orders of the enantiomers were reversed between R‐ and S‐NPCA. The elution orders of d ‐ and l ‐serine unexpectedly reversed between the phosphate buffer at pH 4.0 and pH 2.2, both of which were used in the mobile phase. Separation factors obtained using R‐ and S‐NPCA were similar—1.09 and 1.07, respectively. The detection limit was approximately 940 fmol on the column (signal‐to‐noise ratio 3) when the applied voltage was +650 mV. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
973.
In 1951, P. Lévy represented the Euler and Bernoulli numbers in terms of the moments of Lévy?s stochastic area. Recently the authors extended his result to the case of Eulerian polynomials of types A and B. In this paper, we continue to apply the same method to the Euler and Bernoulli polynomials, and will express these polynomials with the use of Lévy?s stochastic area. Moreover, a natural problem, arising from such representations, to calculate the expectations of polynomials of the stochastic area and the norm of the Brownian motion will be solved. 相似文献
974.
Akio Ohta Takanori Takiue Norihiro Ikeda Makoto Aratono 《Journal of solution chemistry》2001,30(4):335-350
The micellar solutions of polyethylene glycol monooctyl ethers C8Ej (j = 3,4,5) were investigated by employing the high-precision isothermal titration microcalorimeter at seven temperatures from 10° to 40°C. From the thermodynamic analysis of the experimental results, the differential enthalpies of solution of monomer and micelle of C8Ej were obtained separately; they are negative and increase with increasing temperature and decrease with the number j. It was found that C8Ej molecules interact with water molecules more strongly in the monomeric than in micellar state. The enthalpy of micelle formation of C8Ej was positive and decreased with rising temperature, while they increased slightly with increasing j. By comparing the results of ethylene glycol oligomers (C0Ej) with those of C8Ej, it seems reasonable to suppose that the driving force of micelle formation of C8Ej is mainly the increment of entropy caused by dehydration of hydrophilic parts at higher temperatures, while the increment caused by dehydration of hydrophobic parts becomes dominant at lower temperatures in the micellization process. 相似文献
975.
Noriyuki Yonezawa Tetsuo Hino Tsuyoshi Kinuno Toshiyuki Matsuki Tomiki Ikeda 《合成通讯》2013,43(10):1687-1695
Pyruvic acid (3) was found to be arylated chemoselectively at the a-ketocarbonyl carbon in P2O5-MsOH affording decarbonylative α,α-diarylated products 5, decarbonylative a-monoarylated compounds 6, or non-decarbonylative α,α-diarylated adducts 7 depending on the reactivity of arenes (4a-g), in contrast to Lewis acid-catalyzed reaction of its acid chloride (2). 相似文献
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979.
Nohara T Kiyota Y Sakamoto T Manabe H Ono M Ikeda T Fujiwara Y Nakano D Kinjo J 《Chemical & pharmaceutical bulletin》2012,60(6):747-751
Several novel sulfides from acetone extracts of bulbs of garlic (Allium sativum L.), were identified and investigated. These were named garlicnins B(1) (1), C(1) (2), and D (3), and they were found to have the ability to control macrophage activation. Garlicnins B(1) (1) and C(1) (2) possess a new skeleton of cyclic sulfoxide and their structures of garlicnins B(1) (1) and C(1) (2) were characterized as 3,4-dimethyltetrahydrothiophene-S-oxide derivatives carrying the substitutions of a propenyl and a sulfenic acid, and an allyldithiine and a 1-propene-sulfenic acid (a), respectively. The mechanism of the proposed production of these compounds is discussed. Garlicnin D (3), dithiine-type, was estimated to be derived by addition of (a)+allyl thiosulfenic acid (b) derived from allicin. The identification of these novel sufoxides from onion and garlic accumulates a great deal of new chemistry to the Allium sulfide field, and future pharmacological investigations aid the development of natural, healthy foods and anti-cancer agents that could potentially prevent or combat disease. 相似文献
980.
Masato Noguchi Tsukasa Fujieda Wei Chun Huang Masaki Ishihara Atsushi Kobayashi Shin‐ichiro Shoda 《Helvetica chimica acta》2012,95(10):1928-1936
A facile and practical method for synthesis of sugar oxazolines (=dihydrooxazoles) from the corresponding N‐acetyl‐2‐amino sugars has been developed by using 2‐chloro‐1,3‐dimethyl‐1H‐benzimidazol‐3‐ium chloride (CDMBI) as a dehydrative condensing agent. The intramolecular dehydrative reaction between the 2‐acetamido group and the anomeric OH group of unprotected N‐acetyl‐2‐amino sugars took place smoothly in H2O, leading to the formation of a 1,2‐oxazoline (=4,5‐dihydrooxazole) moiety in good yield. Since the reaction proceeds in H2O without using any protecting groups, the resulting oxazolines can be utilized as effective glycosyl donors for the subsequent enzymatic glycosylation. We have successfully demonstrated a highly efficient chemoenzymatic transglycosylation of a disialo‐oligosaccharide moiety to p‐nitrophenyl N‐acetylglucosaminide catalyzed by a mutant endo‐N‐acetylglucosaminidase without isolating disialo‐oligosaccharide oxazoline as synthetic intermediate. 相似文献