78 research outputs found
Flavonoids, bioactive components of propolis, exhibit cytotoxic activity and induce cell cycle arrest and apoptosis in human breast cancer cells MDA-MB-231 and MCF-7 : A comparative study
Breast cancer is one of the most common causes of mortality in women. Flavonoids, among other compounds, are bioactive constituents of propolis. In this comparative study, we investigated the effects of flavonoids apigenin (API), genistein (GEN), hesperidin (HES), naringin (NAR) and quercetin (QUE) on the proliferation, apoptosis, and cell cycle of two different human cancer cells - MDA-MB-231, estrogen-negative, and MCF-7, estrogen-positive receptor breast carcinoma cells. Many cytotoxic reports of flavonoids were performed by MTT assay. However, it's reported that MTT is reduced in metabolically active cells and yields an insoluble purple formazan, which indicates that obtained cytotoxic results of flavonoids could be inconsistent. Cell viability was measured by NR, neutral red assay, while the percentage of apoptotic cells and cell cycle arrest were determined by flow cytometry and Muse cell cycle assay, respectively. The results showed a high dose-dependent effect in cell viability tests. IC50 values were as follows (MCF-7/MDA-MB-231, for 48 h, in \u3bcM): 9.39/50.83 for HES, 25.19/88.17 for API, 40.26/333.51 for NAR, 49.49/47.50 for GEN and 95.12/130.10 for QUE. Flavonoid-induced apoptosis was dose- and time-dependent, for both cancer cell lines, though flavonoids were more active on MCF-7 cells. The flavonoids also induced cell cycle arrest in cancer cells
Determination of Effective Capitalization Rates for Commercial Real Estate
For effective management of the commercial real estate, it is important to determine the capitalization rate. For this purpose, the revenue approach is used. In order for the result to be real for each segment of commercial real estate, it is important to determine the capitalization rates as accurately as possible. This article discusses two methods for calculating the capitalization rate. For the purity of the experiment, the same commercial real estate items in three different segments were used for both methods. This is an office, retail and industrial warehouse. Based on the comparison, one of the two options is selected, which is optimal and detailed. All calculations were made on the example of the city of Yekaterinburg. The time period is six months. Based on the experience gained, the authors suggest using the data obtained for further calculation of the capitalization rate. For clarity of the results obtained, graphs of the dependence of values were compiled. To calculate this indicator, the authors formed a sample of 26 pairs of offers that were simultaneously in the status of full sale and lease. The article presents a constructive and consistent analysis of the capitalization rate calculation using various methods, as well as informative conclusions. We hope that this method will be useful for practical evaluation. © Published under licence by IOP Publishing Ltd
Structural Analysis with Visualization Elements as a Factor in the Development of the Commercial Real Estate Market
This paper presents a universal method of structural analysis of the commercial real estate market with a detailed step-by-step analysis. For example, the analysis was carried out based on commercial real estate in the city of Ekaterinburg. The method is unique in creating visual content that is a map of typical territorial zones of the city of Ekaterinburg. The analysis method also includes the classical structuring of information in the form of tables and diagrams based on real offers for the sale and lease of real estate. The authors formulated forecasts for each segment of the commercial real estate market. Based on this work, anyone can conduct a similar analysis in their city or use it as a base for creating a visualization of the territory according to the zoning given in the work. Having information structured in this way will make it easier to evaluate real estate objects by their real environment. © Published under licence by IOP Publishing Ltd
Fabrication and potential of tunable Ba₀̣₆Sr₀̣₄TiO₃ - Mg₃B₂O₆ composites for microwave applications
An Optical Lattice Clock with Spin-polarized 87Sr Atoms
We present a new evaluation of an 87Sr optical lattice clock using spin
polarized atoms. The frequency of the 1S0-3P0 clock transition is found to be
429 228 004 229 873.6 Hz with a fractional accuracy of 2.6 10^{-15}, a value
that is comparable to the frequency difference between the various primary
standards throughout the world. This measurement is in excellent agreement with
a previous one of similar accuracy
TRIGA-SPEC: A setup for mass spectrometry and laser spectroscopy at the research reactor TRIGA Mainz
The research reactor TRIGA Mainz is an ideal facility to provide neutron-rich
nuclides with production rates sufficiently large for mass spectrometric and
laser spectroscopic studies. Within the TRIGA-SPEC project, a Penning trap as
well as a beam line for collinear laser spectroscopy are being installed.
Several new developments will ensure high sensitivity of the trap setup
enabling mass measurements even on a single ion. Besides neutron-rich fission
products produced in the reactor, also heavy nuclides such as 235-U or 252-Cf
can be investigated for the first time with an off-line ion source. The data
provided by the mass measurements will be of interest for astrophysical
calculations on the rapid neutron-capture process as well as for tests of mass
models in the heavy-mass region. The laser spectroscopic measurements will
yield model-independent information on nuclear ground-state properties such as
nuclear moments and charge radii of neutron-rich nuclei of refractory elements
far from stability. This publication describes the experimental setup as well
as its present status.Comment: 20 pages, 17 figure
Effects of Perfluorocarbons on surfactant exocytosis and membrane properties in isolated alveolar type II cells
<p>Abstract</p> <p>Background</p> <p>Perfluorocarbons (PFC) are used to improve gas exchange in diseased lungs. PFC have been shown to affect various cell types. Thus, effects on alveolar type II (ATII) cells and surfactant metabolism can be expected, data, however, are controversial.</p> <p>Objective</p> <p>The study was performed to test two hypotheses: (I) the effects of PFC on surfactant exocytosis depend on their respective vapor pressures; (II) different pathways of surfactant exocytosis are affected differently by PFC.</p> <p>Methods</p> <p>Isolated ATII cells were exposed to two PFC with different vapor pressures and spontaneous surfactant exocytosis was measured. Furthermore, surfactant exocytosis was stimulated by either ATP, PMA or Ionomycin. The effects of PFC on cell morphology, cellular viability, endocytosis, membrane permeability and fluidity were determined.</p> <p>Results</p> <p>The spontaneous exocytosis was reduced by PFC, however, the ATP and PMA stimulated exocytosis was slightly increased by PFC with high vapor pressure. In contrast, Ionomycin-induced exocytosis was decreased by PFC with low vapor pressure. Cellular uptake of FM 1-43 - a marker of membrane integrity - was increased. However, membrane fluidity, endocytosis and viability were not affected by PFC incubation.</p> <p>Conclusions</p> <p>We conclude that PFC effects can be explained by modest, unspecific interactions with the plasma membrane rather than by specific interactions with intracellular targets.</p
Phase- coherent comparison of two optical frequency standards over 146 km using a telecommunication fiber link
We have explored the performance of two "dark fibers" of a commercial
telecommunication fiber link for a remote comparison of optical clocks. The two
fibers, linking the Leibniz University of Hanover (LUH) with the
Physi-kalisch-Technische Bundesanstalt (PTB) in Braunschweig, are connected in
Hanover to form a total fiber length of 146 km. At PTB the performance of an
optical frequency standard operating at 456 THz was imprinted to a cw trans-fer
laser at 194 THz, and its frequency was transmitted over the fiber. In order to
detect and compensate phase noise related to the optical fiber link we have
built a low-noise optical fiber interferometer and investigated noise sources
that affect the overall performance of the optical link. The frequency
stability at the remote end has been measured using the clock laser of PTB's
Yb+ frequency standard operating at 344 THz. We show that the frequency of a
frequency-stabilized fiber laser can be transmitted over a total fiber length
of 146 km with a relative frequency uncertainty below 1E-19, and short term
frequency instability given by the fractional Allan deviation of
sy(t)=3.3E-15/(t/s)
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