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71.
Circularly polarized luminescence of helically assembled pyrene π‐stacks on RNA and DNA duplexes
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Mitsunobu Nakamura Fuyuki Ota Tadao Takada Kazuo Akagi Kazushige Yamana 《Chirality》2018,30(5):602-608
In this report, we describe the circularly polarized luminescence (CPL) of the RNA duplexes having one to four 2′‐O‐pyrene modified uridines ( Upy ) and the DNA duplexes having two, four, and six pyrene modified non‐nucleosidic linkers ( Py ). Both the pyrene π‐stack arrays formed on the RNA and DNA double helical structures exhibited pyrene excimer fluorescence. In the pyrene‐modified RNA systems, the RNA duplex having four Upy s gives CPL emission with glum value of <0.01 at 480 nm. The structure of pyrene stacks on the RNA duplex may be rigidly regulated with increase in the Upy domains, which resulted in the CPL emission. In the DNA systems, the pyrene‐modified duplexes containing two and four Pys exhibited CPL emission with glum values of <0.001 at 505 nm. The pyrene π‐stack arrays presented here show CPL emission. However, the glum values are relatively small when compared with our previous system consisting of the pyrene‐zipper arrays on RNA. 相似文献
72.
73.
Traditional techniques for assessment of microbial numbers and activity generally lack the specificity required for risk assessment
following environmental release of genetically engineered microbial inocula. Immunological and molecular-based techniques,
such as DNA probing and genetic tagging, were initially used to determine the presence or absence of microorganisms in environmental
samples. Increasingly they are being developed for quantification of populations of specific organisms, either indigenous
or introduced, in the environment. In addition, they are being used to quantify the activity of particular organisms or groups
of organisms, greatly extending the range of techniques available to the microbial ecologist. This article reviews the use
of traditional techniques for the quantification of microbial population size and activity and the application of molecular
techniques, including DNA probing, genetic marking, use of fluorescent probes, and quantitative PCR, in combination with advanced
cell detection techniques such as confocal laser scanning microscopy and flow cytometry. 相似文献
74.
Eu(2+), Dy(3+) and Tb(3+) co-doped strontium aluminate phosphor with high brightness and long afterglow was synthesized by a combustion method, using urea as a reducer. The properties of SrAl(2)O(4):Eu(2+),Dy(3+),Tb(3+) phosphor with a series of initiating combustion temperatures, urea concentrations and boric acid molar fractions were investigated. The sample at initiating combustion temperature of 600 degrees C exhibited an intense emission peak at 513 nm, in which the phosphor existed as a single-phase monoclinic structure. The experimental results showed that the optimum ratio of urea is 2.0 times higher than theoretical quantities and that the suitable molar fraction of H(3)BO(3) is 0.08. The average particle size of the phosphor was 50-80 nm and its luminescence properties were studied systematically. Compared with SrAl(2)O(4):Eu(2+),Dy(3+) phosphor, the initial luminescence brightness improved from 2.50 candela (cd)/m(2) to 3.55 cd/m(2) and the long afterglow time was prolonged from 1290 s to 2743 s. 相似文献
75.
76.
Stanislav Forman Jan Ks Fabiana Fini Mark Steinberg Toms Ruml 《Journal of biochemical and molecular toxicology》1999,13(1):11-15
Testing of the effects of xenobiotics in cultured cells often requires the use of organic solvents to effect suspension of the test agents in cell culture media. However, the toxic effects of the solvents themselves may introduce artifacts, which obscure interpretation of the experimental results. In this article, the toxicity of different solvents commonly used for solvation of a variety of xenobiotic agents was studied. We show that ethanol, acetone, isooctane, methanol, and hexane were considerably less toxic than the more commonly used solvent, DMSO, when ATP content and growth rates of HeLa cells exposed to these solvents was measured. © 1998 John Wiley & Sons, Inc. J Biochem Toxicol 13: 11–15, 1999 相似文献
77.
Volodymyr Maslyuk Oksana Pop Vadym Holovey Vasyl Loya Natalia Svatiuk Mykhailo Birov 《Luminescence》2024,39(4):e4733
The effect of optical radiation during the phase transition from the amorphous to the crystalline state of matter was investigated for the first time. The results were obtained on nanoscale films of (LiF)x(Li2B4O7)1-x compositions by sputtering on cold Ni substrates. The starting materials for films were chosen due to their wide use for tissue-equivalent ionizing radiation dosimetry. It is shown that the detected thermoluminescence effect is sensitive to the thickness of the films. The paper compares the results of these studies with the study of the thermoluminescence characteristics of films irradiated by an M-30 microtron with bremsstrahlung radiation with a maximum energy of 6 MeV. The absorbed radiation dose was 1 kGy. Differences in the luminescence characteristics of irradiated and nonirradiated films were revealed. The nature of the demonstrated structural–optical effect is discussed. 相似文献
78.
Kiran R. Princy A. Masilla S. Moses Kennedy Mohammad I. Sayyed Vikash Mishra Sudha D. Kamath 《Luminescence》2024,39(5):e4750
Ultra-high thermally stable Ca2MgWO6:xSm3+ (x = 0.5, 0.75, 1, 1.25, and 1.5 mol%) double perovskite phosphors were synthesized through solid-state reaction method. Product formation was confirmed by comparing the X-ray diffraction (XRD) patterns of the phosphors with the standard reference file. The structural, morphological, thermal, and optical properties of the prepared phosphor were examined in detail using XRD, Fourier transform infrared spectra, scanning electron microscopy, diffused reflectance spectra, thermogravimetric analysis (TGA), photoluminescence emission, and temperature-dependent PLE (TDPL). It was seen that the phosphor exhibited emission in the reddish region for the near-ultraviolet excitation with moderate Colour Rendering Index values and high colour purity. The optimized phosphor (x = 1.25 mol%) was found to possess a direct optical band gap of 3.31 eV. TGA studies showed the astonishing thermal stability of the optimized phosphor. Additionally, near-zero thermal quenching was seen in TDPL due to elevated phonon-assisted radiative transition. Furthermore, the anti-Stokes and Stokes emission peaks were found to be sensitive toward the temperature change and followed a Boltzmann-type distribution. All these marked properties will make the prepared phosphors a suitable candidate for multifield applications and a fascinating material for further development. 相似文献
79.
Ou Hai Bin Qin Xin Nan Xiao Qiang Ren Xiu Lan Wu Meng Kang Pei Jian Li 《Luminescence》2024,39(2):e4695
The afterglow properties of long afterglow luminescent materials are greatly affected by their defects, which are distributed on the grain surface. Increasing the exposed surface area is an important method to improve the afterglow performance. In this research, long rod-shaped long afterglow materials Sr2MgSi2O7:Eu2+,Dy3+ were prepared using the hydrothermal-coprecipitation method. When the reaction time reached 96 h, the length of the afterglow materials could grow to 2 mm, and the sintering temperature was just 1150°C. The emission spectra of all obtained samples upon excitation at 397 nm had a maximum of 465 nm, which belonged to the representative transition of Eu2+. The initial brightness was 1.35 cd/m2. The afterglow time could reach 19 h, giving a good afterglow performance. The research on this kind of material has essential significance in the exploration of luminescence mechanisms and their applications. 相似文献
80.
《Cell calcium》2017
Aequorins are excellent tools for measuring intra-organellar Ca2+ and assessing its role in physiological and pathological functions. Here we review targeting strategies to express aequorins in various organelles. We address critical topics such as probe affinity tuning as well as normalization and calibration of the signal. We also focus on bioluminescent Ca2+ imaging in nucleus or mitochondria of living cells. Finally, recent advances with a new chimeric GFP-aequorin protein (GAP), which can be used either as luminescent or fluorescent Ca2+ probe, are presented. GAP is robustly expressed in transgenic flies and mice, where it has proven to be a suitable Ca2+ indicator for monitoring physiological Ca2+ signaling ex vivo and in vivo. 相似文献