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591.
592.
Wolfgang Pfeiffer 《Journal of chemical ecology》1978,4(6):665-673
Fifty-nine pteridine, purine, and pyrimidine derivatives were tested with schools of the giant danioDanio malabaricus (Jerdon). The fright reaction was elicited by three pteridine derivatives: 2,6-diamino-4-oxodihydropteridine, isoxanthopterin, and 6-acetonyliso-xanthopterin. A minor effect could not be excluded for three purine derivatives: I-5-MP, IDP, and ITP. 相似文献
593.
Thorsten Falk Ralf Heese Christian Kaspar Malgorzata Mochol Daniel Pfeiffer Michael Thygs Robert Tolksdorf 《Informatik-Spektrum》2006,48(1):201-209
The importance of the Internet for job procurement is increasing for the reason that three quarters of the people in the employment
age are online. On the other hand because ever more companies are publishing their job offers on the Web. However, due to
the large number of openings published online it is almost impossible for job seekers and job portals to gain an overview
of the entire employment market. Since job offers lack semantically meaningful annotations, the search and integration into
databases are made highly difficult. Applying Semantic Web technologies to the e-recruitment process provides advantages for
all participants in the market. In this paper we describe a method for analysing the domain-specific language of an application
domain. We use this method to describe the e-recruitment process and the necessary ontologies for annotating job offers and
job applications. In conclusion, we present the prototypical implementation of the scenario based on Semantic Web, especially
semantic matching. 相似文献
594.
We report the influence of the nonlinearities in the wavelength-sweeping speed on the resulting interferometric signals in an absolute distance interferometer. The sweeping signal is launched in the reference and target interferometers from an external cavity laser source. The experimental results demonstrate a good resolution in spite of the presence of nonlinearities in the wavelength sweep. These nonlinearities can be modeled by a sum of sinusoids. A simulation is then implemented to analyze the influence of their parameters. It shows that a sinusoidal nonlinearity is robust enough to give a good final measurement uncertainty through a Fourier transform technique. It can be concluded that an optimal value of frequency and amplitude exists in the case of a sinusoidal nonlinearity. 相似文献
595.
Glucuronidation is an important pathway in the metabolism of curcumin, but the isoforms of uridine-5'-diphosphoglucuronosyltransferase (UGT) involved are not known. Here, we report on the glucuronidation of the three natural curcuminoids and their major phase I metabolites with microsomes from human liver and intestine as well as with human recombinant UGTs. Microsomes from human liver generated predominantly the phenolic and small amounts of the alcoholic glucuronide of each curcuminoid, whereas intestinal microsomes formed only the phenolic conjugates but with higher activities. The phenolic glucuronidation of the curcuminoids was predominantly catalyzed by hepatic UGT1A1 and intestinal UGT1A8 and 1A10, whereas UGT1A9, 2B7, and 1A8 exhibited high activities for hexahydro-curcuminoids. UGT1A9 was able to form the alcoholic glucuronide of each curcuminoid in addition to the phenolic conjugate. These data suggest that the gastrointestinal tract contributes substantially to the glucuronidation of curcuminoids in humans, which may have important implications for their pharmacokinetic fate in vivo. 相似文献
596.
“Digitalizing Walkability”: Comparing Smartphone-Based and Web-Based Approaches to Measuring Neighborhood Walkability in Singapore 总被引:1,自引:0,他引:1
We evaluated two digitally enabled approaches to measuring neighborhood walkability: a smartphone-based, on-site pedestrian environmental audit tool, WalkTracker (WTracker), and remote, Web-based (Web) observations. Specifically, we examined street segments and intersections of a neighborhood in Singapore assessing: (1) the Inter-Rater Reliability (IRR) of each approach; (2) the Inter-Method Reliability (IMR) across the two approaches; and (3) the average observation times of the two approaches. Each approach had high IRR for the land use and traffic-related domains, with the Web performing better than WTracker for land use. In these same two domains, the two tools were relatively consistent (high IMR), although higher agreement was found within the tools than across them (IRR higher than IMR). For subjective or fine-grained features, both approaches had low IRR, with the Web-based approach performing worse than the app-based approach. Performance across the instruments was also worse than the reliability of measurements within each instrument (IMR lower than IRR). Some items were not observable via the Web. In terms of observation time, there was no statistically significant time difference in measurements between the two observation methods, not including the round-trip travel time to the site. A hybrid approach, combining the two approaches, might be most appropriate. 相似文献
597.
Roland Fitzner Egon Reinold Amaresh Mishra Elena Mena‐Osteritz Hannah Ziehlke Christian Körner Karl Leo Moritz Riede Matthias Weil Olga Tsaryova André Weiß Christian Uhrich Martin Pfeiffer Peter Bäuerle 《Advanced functional materials》2011,21(5):897-910
Efficient synthesis of a series of terminally dicyanovinyl (DCV)‐substituted oligothiophenes, DCVnT 1–6, without solubilizing side chains synthesized via a novel convergent approach and their application as electron donors in vacuum‐processed m‐i‐p‐type planar and p‐i‐n‐type bulk heterojunction organic solar cells is described. Purification of the products via gradient sublimation yields thermally highly stable organic semiconducting materials in single crystalline quality which allows for X‐ray structure analysis. Important insights into the packing features and intermolecular interactions of these promising solar cell materials are provided. Optical absorption spectra and electrochemical properties of the oligomers are investigated and valuable structure–property relationships deduced. Photovoltaic devices incorporating DCVnTs 4–6 showed power conversion efficiencies up to 2.8% for planar and 5.2% for bulk heterojunction organic solar cells under full sun illumination (mismatch corrected simulated AM 1.5G sunlight). The 5.2% efficiency shown here represents one of the highest values ever reported for organic vacuum‐deposited single heterojunction solar cells. 相似文献
598.
D. Gebeyehu B. Maennig J. Drechsel K. Leo M. Pfeiffer 《Solar Energy Materials & Solar Cells》2003,79(1):393
We present a systematic study on photovoltaic devices that combine an organic small molecule photoactive donor–acceptor bulk heterojunction system with controlled doping of the charge transport layers. The doped transport layers are formed using high vacuum co-evaporation deposition technique (i.e. co-sublimation of matrix and dopant). Solar cell devices have been fabricated based on zinc-phthalocyanine (ZnPc) as donor (D) and fullerene (C60) as electron acceptor (A) with doped charge transport layers. The cells show a short circuit current, Isc=1.5 mA/cm2, an open circuit voltage, Voc=450 mV, a fill factor, FF=0.5, and a power conversion efficiency, ηe=3.37% under
sun (10 mW/cm2) white light illumination. In addition, these bulk-heterojunction photovoltaic devices were characterized under 1 sun (100 mW/cm2) white light illumination showing Isc=6.3 mA/cm2, Voc=500 mV, and ηe=1.04%. We have observed that the performance of such ‘bulk-heterojunction’ photovoltaic devices is critically dependent on the transport properties of the interpenetrating network D/A system and doped charge transport layers. 相似文献
599.
The elastic properties of thermal barrier coatings (TBCs) are important for modelling the lifetime of these coatings. A new test setup has been developed to measure the system modulus of electron-beam enhanced physical vapour deposited (EB-PVD) TBC coatings by miniaturized bend tests.Due to the brittleness, low stiffness and small thickness of the top coat and its complex microstructure, it is difficult to measure its Young's modulus by standard mechanical testing. For this reason, a special sample material has been prepared which consists of a 1 mm thick layer of EB-PVD TBC. This material was isothermally heat treated for different times at 950 °C, 1100 °C and 1200 °C and then tested in a specially developed miniaturized bend test. The bend test setup permits mechanical tests with a high resolution in stress and strain, where the strain is measured by digital image correlation. So the stiffness of the free-standing TBC samples could be measured with a high accuracy and the sintering behaviour of the EB-PVD TBC and the consequent rise of Young's modulus could be determined. The results show a significant increase of the system modulus with heat treatment time and temperature caused by sintering of the coating. An activation energy of 220 kJ/mol for the process has been determined.In addition, the material was tested by nanoindentation in order to measure Young's modulus on a local scale, and the porosity of the samples was determined by quantitative image analysis. 相似文献
600.
Jacqueline A. Treat Ryan Pfeiffer Hector Barajas-Martinez Robert J. Goodrow Corina Bot Rodolfo J. Haedo Ronald Knox Jonathan M. Cordeiro 《International journal of molecular sciences》2021,22(13)
Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are used for genetic models of cardiac diseases. We report an arrhythmia syndrome consisting of Early Repolarization Syndrome (ERS) and Short QT Syndrome (SQTS). The index patient (MMRL1215) developed arrhythmia-mediated syncope after electrocution and was found to carry six mutations. Functional alterations resulting from these mutations were examined in patient-derived hiPSC-CMs. Electrophysiological recordings were made in hiPSC-CMs from MMRL1215 and healthy controls. ECG analysis of the index patient showed slurring of the QRS complex and QTc = 326 ms. Action potential (AP) recordings from MMRL1215 myocytes showed slower spontaneous activity and AP duration was shorter. Field potential recordings from MMRL1215 hiPSC-CMs lack a “pseudo” QRS complex suggesting reduced inward current(s). Voltage clamp analysis of ICa showed no difference in the magnitude of current. Measurements of INa reveal a 60% reduction in INa density in MMRL1215 hiPSC-CMs. Steady inactivation and recovery of INa was unaffected. mRNA analysis revealed ANK2 and SCN5A are significantly reduced in hiPSC-CM derived from MMRL1215, consistent with electrophysiological recordings. The polygenic cause of ERS/SQTS phenotype is likely due to a loss of INa due to a mutation in PKP2 coupled with and a gain of function in IK,ATP due to a mutation in ABCC9. 相似文献