排序方式: 共有41条查询结果,搜索用时 15 毫秒
11.
Kovalenko E. S. Podurets K. M. Greshnikov E. A. Zaytseva I. Y. Agafonov S. S. Somenkov V. A. Kolobylina N. N. Kaloyan A. A. Govor L. I. Kurkin V. A. Yatsishina Y. B. 《Crystallography Reports》2019,64(5):841-846
Crystallography Reports - The medieval Russian bronze reliquary cross pendant was investigated using a complex of nondestructive methods in order to determine the degree its integrity and identify... 相似文献
12.
The development of a microfluidic biosensor module with fluorescence detection for the identification of pathogenic organisms and viruses is presented in this article. The microfluidic biosensor consists of a network of microchannels fabricated in polydimethylsiloxane (PDMS) substrate. The microchannels are sealed with a glass substrate and packed in a Plexiglas housing to provide connection to the macro-world and ensure leakage-free flow operation. Reversible sealing permits easy disassembly for cleaning and replacing the microfluidic channels. The fluidic flow is generated by an applied positive pressure gradient, and the module can be operated under continuous solution flow of up to 80 microL min(-1). The biosensor recognition principle is based on DNA/RNA hybridization and liposome signal amplification. Superparamagnetic beads are incorporated into the system as a mobile solid support and are an essential part of the analysis scheme. In this study, the design, fabrication and the optimization of concentrations and amounts of the different biosensor components are carried out. The total time required for an assay is only 15 min including sample incubation time. The biosensor module is designed so that it can be easily integrated with a micro total analysis system, which will combine sample preparation and detection steps onto a single chip. 相似文献
13.
Aye Aye Mar Ali Koohang Nathan D.Majewski Erika L.Szotek David A.Eiznhamer Michael T.Flavin 《中国化学快报》2009,(10)
28-Carboxymethoxy lupane tritepenoids 3 and 4 were synthesized by alkylation of betulin with the THP protected 2- hydroxyethyl iodide followed by oxidation and reduction.Direct reaction of betulin(5) or betulone(10) with ethyl bromoacetate led to 28-O-acylation,instead of 28-O-alkylation.The targeted compounds 3 and 4 were not cytotoxic at the highest concentration tested(75μmol/L),suggesting that elongation of the chain length at the 28-position in both betulinic acid(1) and betulonic acid(2) was detrim... 相似文献
14.
E. V. Zaytseva Yu. V. Gatilov S. A. Amitina R. Tamura I. A. Grigor’ev D. G. Mazhukin 《Russian Journal of Organic Chemistry》2014,50(1):72-77
Stable spirocyclic 2,5-dihydro-1H-imidazole 1-oxyl radicals containing a mesogenic fragment were synthesized on the basis of 1-[4-hydroxy(alkoxy)phenyl]-2-hydroxyamino-2-methylpropan-1-ones. The crystalline structure of two aminoxyl radicals was determined by X-ray analysis. 相似文献
15.
A. A. Shutilov M. N. Simonov Yu. A. Zaytseva G. A. Zenkovets I. L. Simakova 《Kinetics and Catalysis》2013,54(2):184-192
The phase composition, microstructure, and catalytic properties of the samples of ZrO2 and CeO2-ZrO2 calcined in air at 450–500°C in the ketonization reaction of pentanoic acid were studied. It was found that ZrO2 of tetragonal and monoclinic modifications is characterized by sufficiently high activity and selectivity for 5-nonanone; the yield of 5-nonanone was 66.3–64.9%. The modification of zirconium dioxide with cerium oxide leads to the formation of a substitutional solid solution based on tetragonal ZrO2. Upon the addition of CeO2 in an optimum amount of 10 wt % to zirconium dioxide, an increase in the conversion of pentanoic acid was observed with the retention of high selectivity for the target product, which led to an increase in the yield of 5-nonanone to 73.3%. Based on the results of physicochemical studies performed by high-resolution transmission electron microscopy, X-ray diffraction analysis, and X-ray photoelectron spectroscopy, the physicochemical and catalytic properties of the test catalysts were compared. 相似文献
16.
Bondarenko Marina Zaytseva Olga Trusova Valeriya Moiseenko Anton Rukin Aleksey Utytskykh Tetyana Morozova Oksana 《Journal of fluorescence》2021,31(4):1065-1073
Journal of Fluorescence - This study is devoted to the development of a methodological approach to mathematical analysis and data interpretation of blood serum phosphorescence intensity in cancer... 相似文献
17.
In this paper, electrical and structural properties of mono-, di-, tri- and tetrachlorothiophenes and their radical cations
have been studied using the density functional theory and B3LYP method with 6-311++G** basis set. The effects of the number
and position of the substituent of chlorine atoms on the properties of the thiophene ring for all chlorothiophenes and their
radical cations have been studied. Vibrational frequencies, nuclear chemical shielding constants, spin-density distribution,
size and direction of dipole moment vector, ionization potential, electric polarizabilities and NICS values of these compounds
have been calculated as well. The analysis of these data showed that double bonds in 3-chlorothiophene are more delocalized
and it is the best possible candidate monomer among all chlorothiophenes for the synthesis of corresponding conducting polymers
with modified characteristics. 相似文献
18.
Zaytseva NV Montagna RA Lee EM Baeumner AJ 《Analytical and bioanalytical chemistry》2004,380(1):46-53
A multi-analyte biosensor based on nucleic acid hybridization and liposome signal amplification was developed for the rapid serotype-specific detection of Dengue virus. After RNA amplification, detection of Dengue virus specific serotypes can be accomplished using a single analysis within 25 min. The multi-analyte biosensor is based on single-analyte assays (see Baeumner et al (2002) Anal Chem 74:1442–1448) developed earlier in which four analyses were required for specific serotype identification of Dengue virus samples. The multi-analyte biosensor employs generic and serotype-specific DNA probes, which hybridize with Dengue RNA that is amplified by the isothermal nucleic acid sequence based amplification (NASBA) reaction. The generic probe (reporter probe) is coupled to dye-entrapping liposomes and can hybridize to all four Dengue serotypes, while the serotype-specific probes (capture probes) are immobilized through biotin–streptavidin interaction on the surface of a polyethersulfone membrane strip in separate locations. A mixture of amplified Dengue virus RNA sequences and liposomes is applied to the membrane and allowed to migrate up along the test strip. After the liposome-target sequence complexes hybridize to the specific probes immobilized in the capture zones of the membrane strip, the Dengue serotype present in the sample can be determined. The amount of liposomes immobilized in the various capture zones directly correlates to the amount of viral RNA in the sample and can be quantified by a portable reflectometer. The specific arrangement of the capture zones and the use of unlabeled oligonucleotides (cold probes) enabled us to dramatically reduce the cross-reactivity of Dengue virus serotypes. Therefore, a single biosensor can be used to detect the exact Dengue serotype present in the sample. In addition, the biosensor can simultaneously detect two serotypes and so it is useful for the identification of possible concurrent infections found in clinical samples. The various biosensor components have been optimized with respect to specificity and sensitivity, and the system has been ultimately tested using blind coded samples. The biosensor demonstrated 92% reliability in Dengue serotype determination. Following isothermal amplification of the target sequences, the biosensor had a detection limit of 50 RNA molecules for serotype 2, 500 RNA molecules for serotypes 3 and 4, and 50,000 molecules for serotype 1. The multi-analyte biosensor is portable, inexpensive, and very easy to use and represents an alternative to current detection methods coupled with nucleic acid amplification reactions such as electrochemiluminescence, or those based on more expensive and time consuming methods such as ELISA or tissue culture. 相似文献
19.
E. M. Zaytseva R. D. Govorun G. V. Mitsin A. G. Molokanov 《Physics of Particles and Nuclei Letters》2011,8(6):599-605
The effectiveness of the impact of therapeutic proton beams in human cells with respect to the criterion of formation of chromosome
aberrations in human-blood lymphocytes is estimated. The physical characteristics of radiation (proton LET at the input of
the object and in the region of the modified Bragg peak) and the role of the biological factor (the differences in the radiosensitivity
of nondividing cells corresponding to the irradiation of normal tissues along the proton-beam path and tumor tissues) are
taken into account. The relative biological effectiveness of protons is ∼1 at the beam input of the object and ∼1.2 in the
Bragg peak region. Taking into account the higher radiosensitivity of dividing cells in the G
2 phase of the cell cycle, the irradiation effectiveness increases to ∼1.4. 相似文献
20.
The Advanced Photon Source (APS) at Argonne National Laboratory is considering the development of a superconducting linac-based fourth-generation hard X-ray source to meet future scientific needs of the hard X-ray user community. This work specifically focuses on the design of an optimized 5-cell superconducting radio-frequency structure well suited for a high-energy, high-beam-current energy recovery linac. The cavity design parameters are based on the APS storage ring nominal 7 GeV and 100 mA beam operation. A high-current 5-cell cw superconducting cavity operating at 1.4 GHz has been designed. In order to achieve a high current, the accelerating cavity shape has been optimized and large end-cell beam pipes have been adopted. The beam break-up threshold of the cavity has been estimated using the code TDBBU, which predicts a high threshold beam current for a 7 GeV energy recovery linac model. A copper prototype cavity has been fabricated that uses half-cell modules, initially assembled by clamping the cells together. 相似文献