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排序方式: 共有185条查询结果,搜索用时 109 毫秒
71.
So HM Won K Kim YH Kim BK Ryu BH Na PS Kim H Lee JO 《Journal of the American Chemical Society》2005,127(34):11906-11907
We report the real-time detection of protein using SWNT-FET-based biosensors comprising DNA aptamers as molecular recognition elements. Anti-thrombin aptamers that are highly specific to serine protein thrombin were immobilized on the sidewall of a SWNT-FET using CDI-Tween linking molecules. The binding of thrombin aptamers to SWNT-FETs causes a rightward shift of the threshold gate voltages, presumably due to the negatively charged backbone of the DNA aptamers. While the addition of thrombin solution causes an abrupt decrease in the conductance of the thrombin aptamer immobilized SWNT-FET, no noticeable change was observed with elastase. 相似文献
72.
Mi Jin Kim Myung Jin Jung Yeong Joon Kim Ha Kyoung Sung Ju Young Lee Sung Jin Ham Chan Pil Park 《Tetrahedron letters》2018,59(31):2989-2993
The Pd(II) complexes strongly chelated by two β-iminoenolate ligands were easily synthesized in only two steps, and purified based on their sublimable and highly stable property. The Pd(II) complexes anchored on a silica surface showed good catalytic activity in Suzuki-Miyaura reactions (up to 99% yield with 0.05?mol% catalyst). They tolerated a wide range of temperature (rt~110?°C) and various solvents, and could be reused multiple times after simple recovering process. 相似文献
73.
Lucia Očenášová Peter Kutschy Jozef Gonda Martina Pilátová Gabriela Gönciová Ján Mojžiš Pavel Pazdera 《Chemical Papers》2016,70(5):635-648
Electrophilic aromatic substitution is one of the most thoroughly studied reactions in organic chemistry. In the present paper, the 5-brominated spirobrassinol methyl ethers VII, VIII were obtained by electrophilic substitution of the aromatic core of indoline at the C-5 position in the presence of various brominating agents. The same products were also prepared from 5-bromoindole (IX) following the sequence for the synthesis 1-methoxyspirobrassinol methyl ether (V) from indoline. In addition, the new related 5-bromospiroindoline derivatives XX–XXIII were synthesised and their biological activity on human tumour cell lines was examined. The presence of bromine in the indole or indoline skeleton at the C-5 position resulted in the partial increase in anticancer activity on leukaemia cell lines (Jurkat, CEM). The structures of the newly prepared products were determined by 1H and 13C NMR spectroscopy, including HSQC, HMBC, COSY, NOESY and DEPT measurements. 相似文献
74.
Larchenko A. V. Lebed’ O. M. Blagoveshchenskaya N. F. Pil’gaev S.V. Beketova E. B. Fedorenko Yu.V. 《Radiophysics and Quantum Electronics》2022,64(11):761-779
Radiophysics and Quantum Electronics - We consider the results of observations of the ELF/VLF horizontal magnetic field of the ionospheric source using a high-latitude network of PGI stations in... 相似文献
75.
76.
An-Sofie Goessaert Kristof Pil Jolien Veramme Alain Verstraete 《Analytical and bioanalytical chemistry》2010,396(7):2461-2468
There is a need for a reliable rapid on-site oral fluid test that can be used in police controls to detect impaired drivers. We evaluated the Varian Oralab®6 and collected two oral fluid samples from 250 subjects, one with the Varian Oralab®6 and one with the StatSure? Saliva?Sampler?. The Oralab®6 can detect six drug types: amphetamines, methamphetamine, cocaine, opiates, delta9-tetrahydrocannabinol (THC), and phencyclidine (PCP). On-site results were obtained within 10 to 15 min. The sample collected with StatSure? was analyzed using liquid chromatography–tandem mass spectrometry after liquid–liquid extraction and these results were used as a reference to determine prevalence, sensitivity, and specificity. Two cut-off values were used in the evaluation. The Varian cut-off values were: amphetamine 50 ng/mL, cocaine 20 ng/mL, opiates 40 ng/mL, and THC 50 ng/mL. The DRUID cut-offs were: amphetamine 25 ng/mL, cocaine 20 ng/mL, opiates 20 ng/mL, and THC 1 ng/mL. Applying the first cut-offs, prevalence, sensitivity, and specificity were: amphetamine 10%, 76%, 100%; cocaine 23%, 34%, 100%; opiates 38%, 83%, 94%; and THC 18%, 41%, 99%. The DRUID cut-off values gave the following results: amphetamine 14%, 56%, 100%; cocaine 28%, 34%, 100%; opiates 49%, 68%, 98%, and THC 45%, 16%, 99%. The specificity of the Oralab®6 is generally good. For both cut-offs, sensitivity was low for cocaine and THC. Therefore, the Varian Oralab®6 test is not sensitive enough to be applied during roadside police controls. 相似文献
77.
78.
We investigate the effect of delay in feedback on the oscillation characteristics (amplitude and frequency) of a string generator,
which, as is well known, works in a self-induced oscillation mode and is a part of a string accelerometer (a device for measuring
the acceleration of ballistic missiles, launch vehicles, and other moving objects). A mathematical model of the dynamics of
a string generator is taken in the form of a quasilinear second-order hyperbolic equation with constant delay with respect
to one of independent variables (time). For the analysis of the mathematical model, we use the one-frequency asymptotic Krylov-Bogolyubov-Mitropol'skii
method (its first and second approximations) of nonlinear mechanics. We show that an increase in the delay in the nonlinear
feedback amplifier results in a decrease in the frequency of self-induced oscillations, which transforms the string generator
into a low-frequency device.
__________
Translated from Neliniini Kolyvannya, Vol. 11, No. 2, pp. 168–190, April–June, 2008. 相似文献
79.
Kang SH Na JH Moon SN Lee WI Yoo PJ Lee SD 《Langmuir : the ACS journal of surfaces and colloids》2012,28(7):3576-3582
Anisotropic wrinkling which utilizes the anisotropic nature of liquid crystalline polymer (LCP) is demonstrated as a means of physical self-assembly to produce periodic microstructures. Through the plasma treatment on the molecularly aligned LCP film surface, one-dimensionally ordered wrinkle pattern was spontaneously formed on glass substrates without employing external thin-film deposition or prestrain control of the system. Experimental results indicate that the directionality of the wrinkle pattern can be tailored by the structural ordering of LCP molecules in the bilayer system of a hard skin layer on a soft substrate. Studies on process variables, such as the plasma treatment time and the film thickness, were conducted to figure out the effect on the wrinkling morphology. Due to its spatial periodicity over a large area and undemanding requirement of the process, this approach can be a candidate for the microfabrication in various applications. 相似文献
80.
Alison G. Pacheco Viviane C. Abreu Heitor A. De Abreu Dorila Piló-Veloso Antônio F. de C. Alcântara 《Structural chemistry》2012,23(3):703-710
Aristolactam AII (1) and aristolochic acid I (2) were employed as examples in choosing the most suitable theoretical methodology for computing carbon chemical shifts (Calc
δ
C) and for the structural elucidations of aristolactams and aristolochic acids. Geometries of 1 and 2 optimized using HF, BLYP, B3LYP, and PBE methods and 6-311++G** basis set were subjected to δC calculations and the calculated chemical shifts obtained were correlated with their 13C NMR data. Different possibilities were considered (in the gaseous phase, model PCM (DMSO), and for dimeric systems 1-1 and 2-2), and an explicit solvent (DMSO) model employing BLYP/6-31G* calculations was determined to be the most efficient (R
2 = 0.99631 and 0.97713, for 1 and 2, respectively). 相似文献