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91.
Malay Patra Gilles Gasser Dr. Antonio Pinto Klaus Merz Dr. Ingo Ott Prof. Dr. Julia E. Bandow Prof. Dr. Nils Metzler‐Nolte Prof. Dr. 《ChemMedChem》2009,4(11):1930-1938
The recent discovery of the natural product platensimycin as a new antibiotic lead structure has triggered the synthesis of numerous organic derivatives for structure–activity relationship studies. Herein, we describe the synthesis, characterization and biological evaluation of the first organometallic antibiotic inspired by platensimycin. Two bioorganometallic compounds containing (η6‐pentamethylbenzene)Cr(CO)3 ( 2 ) and (η6‐benzene)Cr(CO)3 ( 3 ), linked by an amide bond to the aromatic part of platensimycin, were synthesized. Their antibiotic activities were tested against B. subtilis 168 (Gram positive) and E. coli W3110 (Gram negative) bacterial strains. Both compounds were found to be inactive against E. coli but derivative 2 inhibits B. subtilis growth at a moderate MIC value of 0.15 mM . To test the intrinsic toxicity of chromium, several chromium salts along with {η6‐(3‐pentamethylphenyl propionic acid)}Cr(CO)3 ( 5 ) and {η6‐(3‐phenyl propionic acid)}Cr(CO)3 ( 6 ) were tested against both bacterial strains. No activity was observed against E. coli for any of the compounds; B. subtilis growth was not inhibited by Cr(NO3)3 and only very weakly by 5 , K2Cr2O7 and Na2CrO4 at MIC values of 0.5, 0.68 and 1.24 mM , respectively. Compounds 2 , 3 , 5 and 4 (the pure organic analogue of 2 ) show similar cytotoxicity against HeLa, HepG2 and HT‐29 mammalian cell lines. Furthermore, the cellular uptake and the intracellular distribution of compounds 2 , 3 and Cr(NO3)3 in B. subtilis were studied using atomic absorption spectroscopy to gain insight in to the possible cellular targets. Compound 2 was found to be readily taken up and distributed almost equally among cytosol, cell debris and cell membrane in B. subtilis. 相似文献
92.
This study investigated the influence of verbal self-instructions (VSI) on the transfer of task-switching training in older adults (56–78 years). We applied an internally cued switching paradigm in a pretest–training–posttest design. Training-related improvements were not modulated by VSI. Transfer (the pretest–posttest reduction of switch costs) was most pronounced when participants applied the VSI at posttest after practicing the switching task without VSI. The results indicate that in contrast to transfer of executive control training, transfer of (verbal) strategy training seems to be limited and that VSI is most beneficial when the task-switching abilities are already well practiced. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
93.
In 2002, the authors established a baseline for Internet users' online privacy values, finding information transfer, notice/awareness, and information storage were the top online privacy concerns. Since this survey, many privacy-related events have occurred, including changes in online trends and the creation of laws, prompting the authors to rerun the survey in 2008 to examine how these events might have affected users' online privacy concerns. In this article, they discuss the 2008 survey, which revealed that US Internet users' top three privacy concerns didn't change over the course of six years, although their level of concern did. The authors also examine differences in privacy concerns between US and international respondents. The Web extra groups the survey statements according to six dimensions of privacy concerns based on the following classifications—personalization, notice/awareness, information transfer, information collection, information storage, and access/participation. 相似文献
94.
Julia Heidemann 《Informatik-Spektrum》2010,49(6):262-271
Online Social Networks wie Xing.com oder Facebook.com geh?ren zu den am st?rksten wachsenden Diensten im Internet. Im Jahr
2008 nutzten gesch?tzte 580 Mio. Menschen weltweit diese Angebote. Entsprechend schnell haben sich Online Social Networks
innerhalb weniger Jahre von einem Nischenph?nomen zu einem weltweiten Medium der IT-gestützten Kommunikation entwickelt. Insbesondere
aufgrund stark wachsender Mitgliederzahlen entfalten Online Social Networks eine erhebliche gesellschaftliche und wirtschaftliche
Bedeutung. Vor diesem Hintergrund ist es Ziel dieses Beitrags, Begriff und Eigenschaften, Entstehung und Entwicklung sowie
Nutzenpotenziale und Herausforderungen von Online Social Networks n?her zu untersuchen. 相似文献
95.
Andreas Opitz Bernhard Ecker Julia Wagner Alexander Hinderhofer Frank Schreiber Jochen Manara Jens Pflaum Wolfgang Brütting 《Organic Electronics》2009,10(7):1259-1267
Blends of organic electron and hole conductive materials are widely used for ambipolar charge carrier transport and photovoltaic cells. An obvious choice for donor–acceptor blends are organic semiconducting materials in their hydrogenated and fluorinated form, since they combine potentially suitable electronic properties with structural compatibility of the two constituents. This study focuses on the structural, optical, and electrical properties of blends using hydrogenated copper-phthalocyanine (H16CuPc) in combination with its per-fluorinated version (F16CuPc). Using X-ray scattering, scanning force microscopy and optical absorption measurements we show that mixed crystalline films are obtained by co-evaporation of the two materials. Electrical transport measurements reveal a profound reduction of the current for bipolar charge injection in mixed films. We discuss the formation of self-trapped charge transfer excitons as possible explanation for this unexpected behaviour, which impedes the usability of this system in photovoltaic cells. 相似文献
96.
Toluenesulfonate-acyl esters of ethylene glycol and other 1,2-diols as industrial antioxidants with cupric ion 总被引:2,自引:0,他引:2
Yongyi?Julia?Jiang Earl?G.?HammondEmail author 《Journal of the American Oil Chemists' Society》2002,79(8):791-796
Ethylene glycol esters of soybean oil FA increased in viscosity much more slowly than methyl or glycerol esters when oxidized
at 105°C in the presence of flowing air and colloidal copper. This increased stability was caused by a minor constituent of
the ethylene glycol esters, which was shown by MS to be a mixed ethanediol fatty acylate p-toluenesulfonate (EFAT). The p-toluenesulfonate group came from the catalyst used in the formation of the ethylene glycol esters. EFAT was quantified by
UV spectrometry, HPLC, or GC of the acyl group that it contains. EFAT could be synthesized in good yield by reacting ethylene
glycol, a FA, and p-toluenesulfonic acid (TSA) in a 1∶1∶1 molar ratio using a benzene azeotrope to remove water of esterification. EFAT increased
the time required for the polymerization of soybean oil by about 27 times but required concentrations of 2–5% by weight. EFAT
made with a variety of FA were active in delaying viscosity increase. Ethyl and decyl p-toluenesulfonate were inactive. Replacing ethylene glycol by glycerol and 1,2-propylene glycol but not by 1,3-propylene glycol
resulted in active EFAT. TSA itself delayed the polymerization of soybean oil, especially in the presence of free ethylene
glycol and FA, but this probably was caused by formation of EFAT during the oxidation test. Colloidal copper could be replaced
by cupric ion. EFAT-copper appeared to act as an antioxidant by destroying hydroperoxides without initiation of free radical
chains. 相似文献
97.
Automatic construction of multiple-object three-dimensional statistical shape models: application to cardiac modeling 总被引:3,自引:0,他引:3
Frangi AF Rueckert D Schnabel JA Niessen WJ 《IEEE transactions on medical imaging》2002,21(9):1151-1166
A novel method is introduced for the generation of landmarks for three-dimensional (3-D) shapes and the construction of the corresponding 3-D statistical shape models. Automatic landmarking of a set of manual segmentations from a class of shapes is achieved by 1) construction of an atlas of the class, 2) automatic extraction of the landmarks from the atlas, and 3) subsequent propagation of these landmarks to each example shape via a volumetric nonrigid registration technique using multiresolution B-spline deformations. This approach presents some advantages over previously published methods: it can treat multiple-part structures and requires less restrictive assumptions on the structure's topology. In this paper, we address the problem of building a 3-D statistical shape model of the left and right ventricle of the heart from 3-D magnetic resonance images. The average accuracy in landmark propagation is shown to be below 2.2 mm. This application demonstrates the robustness and accuracy of the method in the presence of large shape variability and multiple objects. 相似文献
98.
Jeffrey A. Cook Jing Sun Julia H. Buckland Ilya V. Kolmanovsky Huei Peng Jessy W. Grizzle 《Asian journal of control》2006,8(3):237-260
This paper surveys recent and historical publications on automotive powertrain control. Control‐oriented models of gasoline and diesel engines and their aftertreatment systems are reviewed, and challenging control problems for conventional engines, hybrid vehicles and fuel cell powertrains are discussed. Fundamentals are revisited and advancements are highlighted. A comprehensive list of references is provided. 相似文献
99.
Hay Julia L.; Milders Maarten M.; Sahraie Arash; Niedeggen Michael 《Canadian Metallurgical Quarterly》2006,32(4):885
Recent visual marking studies have shown that the carry-over of distractor inhibition can impair the ability of singletons to capture attention if the singleton and distractors share features. The current study extends this finding to first-order motion targets and distractors, clearly separated in time by a visual cue (the letter X). Target motion discrimination was significantly impaired, a result attributed to the carry-over of distractor inhibition. Increasing the difficulty of cue detection increased the motion target impairment, as distractor inhibition is thought to increase under demanding (high load) conditions in order to maximize selection efficiency. The apparent conflict with studies reporting reduced distractor inhibition under high load conditions was resolved by distinguishing between the effects of "cognitive" and "perceptual" load. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
100.