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排序方式: 共有127条查询结果,搜索用时 437 毫秒
1.
2.
Congo red (CR) is an azo dye which not only preferentially binds to elastin, an extracellular matrix protein found in the media of arterial vessel walls, but also fluoresces when it binds to this protein. Protein solubilization data following laser irradiation of elastin:CR suspensions determined that the amount of elastin solubilized by laser irradiation increased with the increase in CR. The saturation point of CR to elastin was attained when 400 g CR was added to 20 mg elastin suspension. When 20 ml of a 5% CR solution in 5% dextrose was administered intravenously, the CR was absorbed in levels sufficient to produce fluorescence of the main arteries in rabbits. Layers of tissue both in the media of the vessels and at the endothelial/intimal interface were clearly differentiated. Therefore, the elastin:CR complex appears to be an ideal system in which the elastin fluorescence could aid in distinguishing between normal and diseased tissue in certain pathological conditions, such as atherosclerosis and some types of breast tumors. 相似文献
3.
A. A. Naqvi Faris A. Al-Matouq F. Z. Khiari Khateeb-ur-Rehman M. A. Gondal A. A. Isab 《Journal of Radioanalytical and Nuclear Chemistry》2013,296(1):215-221
A thermal neutron capture-based Prompt Gamma ray Activation Analysis setup has been designed to analyze the elemental concentration of environmental bulk samples using a D(d,n) reaction-based portable neutron generator. The performance of the setup was tested through mercury concentration measurements in Hg-contaminated water samples using a large volume cylindrical bismuth germinate (BGO) gamma ray detector. Excellent agreement of experimental count rate of 2.64, 3.19 + 3.29 and 4.67–5.05 MeV Hg prompt gamma rays with theoretical count rate obtained through Monte Carlo simulations, indicates excellent performance of the newly designed portable neutron generator-based PGNAA setup. 相似文献
4.
Mohamed A. Salem Samir Y. Abbas Mohamed H. Helal Abdullah Y. Alzahrani 《Journal of heterocyclic chemistry》2021,58(11):2117-2123
As trail to overcome on the antimicrobial drug-resistance problems, new functionalized 2-pyridinone and 2-iminochromene derivatives bearing morpholine moiety were designed and synthesized. The 2-pyridinone derivatives were obtained through the cyclization of cyanoacetohydrazone of 4-morpholinylacetophenone with 1,3-dicarbonyl compounds, α,β-unsaturated nitriles or 2-(arylidene)malononitriles. The 2-iminochromene derivatives were synthesized through the ring closure of cyanoacetohydrazonewith salicylaldehyde derivatives. The antibacterial and antifungal activities for the synthesized 2-pyridinone and 2-iminochromene derivatives were investigated. Most of the tested compounds showed moderate activity against P. vulgaris. Compounds 4a,b and 5a,b showed moderate activity against G −ve bacteria. All iminochromene derivatives showed moderate activity against C. albicans. Compound 8c was the most active compound. 相似文献
5.
Ibrahim Mssillou Abdelkrim Agour Aimad Allali Hamza Saghrouchni Mohammed Bourhia Abdelfattah El Moussaoui Ahmad Mohammad Salamatullah Abdulhakeem Alzahrani Mourad A. M. Aboul-Soud John P. Giesy Badiaa Lyoussi Elhoussine Derwich 《Molecules (Basel, Switzerland)》2022,27(7)
Since some synthetic insecticides cause damage to human health, compounds in plants can be viable alternatives to conventional synthetic pesticides. Dittrichia viscosa L. is a perennial Mediterranean plant known to possess biological activities, including insecticidal properties. The chemical composition of an essential oil (EOD) from D. viscosa, as well as its antioxidant, antimicrobial, and insecticidal effects on the cowpea weevil (Callosobruchus maculatus) were determined. Forty-one volatile compounds were identified in EOD, which accounted for 97.5% of its constituents. Bornyl acetate (41%) was a major compound, followed by borneol (9.3%), α-amorphene (6.6%), and caryophyllene oxide (5.7%). EOD exhibited significant antioxidant activity in all tests performed, with an IC50 of 1.30 ± 0.05 mg/mL in the DPPH test and an EC50 equal to 36.0 ± 2.5 mg/mL in the FRAP assay. In the phosphor-molybdenum test, EOD results ranged from 39.81 ± 0.7 to 192.1 ± 0.8 mg AAE/g E. EOD was active on E. coli (9.5 ± 0.5 mm), S. aureus (31.0 ± 1.5 mm), C. albicans (20.4 ± 0.5 mm), and S. cerevisiae (28.0 ± 1.0 mm), with MICs ranging from 0.1 mg/mL to 3.3 mg/mL. We found that 1 µL of EOD caused 97.5 ± 5.0% insect mortality after 96 h in the inhalation test and 60.0 ± 8.3% in the ingestion assay. The median lethal concentration (LC50) was 7.8 ± 0.3 μL EO/L, while the effective concentration in the ingestion test (LC50) was 15.0 ± 2.1 μL EO/L. We found that 20 µL of EOD caused a reduction of more than 91% of C. maculatus laid eggs. 相似文献
6.
The nonlinear interaction of electron beam with inhomogeneous semi-bounded collisional magnetized warm plasma under external static magnetic field has been studied. The second-harmonic generation at the beam entrance into the plasma is considered. This process leads to an increase in the amplitude of the electric field in the inhomogeneous region and, in turn, to higher absorption. 相似文献
7.
Dynamics of cooperative emissions in a cascade three-level molecular system driven by an ultrashort laser pulse
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This paper investigates the dynamics of cooperative emissions in a cascade three-level system driven by an ultra, short laser pulse by solving numerically the full-wave Maxwell-Bloch equations. The 4, 4'-bis(dimethylamino) stilbene molecule is used as the model molecule because of its strong two-photon absorption property. The two-colour cooperative emissions are studied as functions of molecular number density and dephasing rate of the dipole coherence. The propagation effects on the evolution of the cooperative radiations are also taken into account. The cooperative radiations are enhanced for large number density of the molecule, while the fast dephasing of the dipole coherence reduces the intensity of the cooperative radiations and delays the emission times or even inhibits the formation of the emissions. The delay time of the radiation decreases with the increase of the molecular number density and the propagation distance. 相似文献
8.
We report high-precision measurements of the absorption and the reduced scattering coefficients for turbid media. Using a frequency-domain measurement technique for a point-source infinite-medium geometry, we find that the standard deviations of multiple measurements of the absorption coefficient mu(a) and the reduced scattering coefficient mu(s)(?) are less than 0.6%, and three independently derived values for mu(a) and mu(s)(?) agree to better than 1%. Measurements of mu(a) agree with measurements of a nonscattering medium to within 1.2%. To obtain high precision requires attention to proper conditions for the spherical photon-density wave model, the detection linearity, and the ratio of the absorption rate to the source modulation rate. Frequency-domain amplitude and phase measurements deviate from fitted curves by 0.1% and 0.06 degrees rms, respectively. 相似文献
9.
William G. Faris 《Communications in Mathematical Physics》1973,30(1):23-34
LetH
00 be a self-adjoint operator acting in a spaceL
2(M, ). It is assumed thatH
0
e=0, wheree is strictly positive, and that exp(–tH
0) is positivity preserving fort0. LetV be a real function onM such that its positive part is inL
2(M,e
2) and its negative part is relatively small with respect toH
0. ThenH=H
0+V is essentially self-adjoint on the intersection of the domains ofH
0 andV. This result is applied to Schrödinger operators and to quantum field Hamiltonians. 相似文献
10.
We have prepared and characterized several lanthanide ion complexes of multidentate ligands or chelates in an effort to develop new upconverting luminescent labels that can be immune to autofluorescence and photobleaching. This study has involved the characterization of various chelates of Nd, Er, and Tm with respect to relative luminescent efficiency and excited-state lifetimes and explored various two-photon stepwise excitation mechanisms. Using peak laser powers near 100 kW, the upconversion emissions of Nd in Nd(EDTA)2(5-) at 386 nm, Er in Er(DPA)3(3-) at 550 nm, and Tm in Tm(DPA)3(3-) at 480 nm, at levels of approximately 10(-12) moles can be detected. 相似文献