2,428 research outputs found
Seasonal variations in the Sr-Nd isotopic compositions of suspended particulate matter in the lower Changjiang River: Provenance and erosion constraints
Study on Smoke Control of Wuhan CBD Urban Traffic Link Tunnel
AbstractAn Urban Traffic Link Tunnel (UTLT) is a novel type of underground transportation system consisting of a main tunnel in a loop shape and several linked tunnels. It has a higher level of fire risk compared to other common road tunnels. In this study, numerical and experimental study has been conducted to investigate the smoke control of Wuhan Central Business District (CBD) UTLT. The transient distributions of the smoke spread have been analyzed, and the optimal smoke control strategy for the Wuhan CBD UTLT has been put forward
TMRT observations of 26 pulsars at 8.6 GHz
Integrated pulse profiles at 8.6~GHz obtained with the Shanghai Tian Ma Radio
Telescope (TMRT) are presented for a sample of 26 pulsars. Mean flux densities
and pulse width parameters of these pulsars are estimated. For eleven pulsars
these are the first high-frequency observations and for a further four, our
observations have a better signal-to-noise ratio than previous observations.
For one (PSR J0742-2822) the 8.6~GHz profiles differs from previously observed
profiles. A comparison of 19 profiles with those at other frequencies shows
that in nine cases the separation between the outmost leading and trailing
components decreases with frequency, roughly in agreement with
radius-to-frequency mapping, whereas in the other ten the separation is nearly
constant. Different spectral indices of profile components lead to the
variation of integrated pulse profile shapes with frequency. In seven pulsars
with multi-component profiles, the spectral indices of the central components
are steeper than those of the outer components. For the 12 pulsars with
multi-component profiles in the high-frequency sample, we estimate the core
width using gaussian fitting and discuss the width-period relationship.Comment: 33 pages, 49 figures, 5 Tables; accepted by Ap
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In Vivo Regulation of E2F1 by Polycomb Group Genes in Drosophila
The E2F transcription factors are important regulators of the cell cycle whose function is commonly misregulated in cancer. To identify novel regulators of E2F1 activity in vivo, we used Drosophila to conduct genetic screens. For this, we generated transgenic lines that allow the tissue-specific depletion of dE2F1 by RNAi. Expression of these transgenes using Gal4 drivers in the eyes and wings generated reliable and modifiable phenotypes. We then conducted genetic screens testing the capacity of Exelixis deficiencies to modify these E2F1-RNAi phenotypes. From these screens, we identified mutant alleles of Suppressor of zeste 2 [Su(z)2] and multiple Polycomb group genes as strong suppressors of the E2F1-RNA interference phenotypes. In validation of our genetic data, we find that depleting Su(z)2 in cultured Drosophila cells restores the cell-proliferation defects caused by reduction of dE2F1 by elevating the level of dE2f1. Furthermore, analyses of methylation status of histone H3 lysine 27 (H3K27me) from the published modENCODE data sets suggest that the genomic regions harboring dE2f1 gene and certain dE2f1 target genes display H3K27me during development and in several Drosophila cell lines. These in vivo observations suggest that the Polycomb group may regulate cell proliferation by repressing the transcription of dE2f1 and certain dE2F1 target genes. This mechanism may play an important role in coordinating cellular differentiation and proliferation during Drosophila development
Tricyclic Neovibsanin Scaffold Inhibits Glioma by Targeting Glioma-Initiating Cells
Purpose: To investigate the effect of tricyclic neovibsanin scaffold (TCNS) on cell viability, colony formation capacity and induction of apoptosis in glioma cells.Methods: 3-(4, 5-Dimethylthiazol-2-yl) 2, 5-diphe¬nyltetrazolium bromide (MTT) assay was used to analyze the effect of TCNS on cell proliferation. Light microscopic examination of giemsa solution stained cells was used to calculate the number of colonies with > 50 cells. Flow cytometry using a flow cytometer, while apoptosis detection kit were used to analyze induction of apoptosis.Results: TCNS treatment significantly inhibited the viability of U138 NS and U138 AC cells in a concentration-dependent manner (p < 0.05). TCNS caused 86 % reduction in the capacity of U138 NS cells to form colonies and led to significant induction of apoptosis. The activation of caspase 3 and expression of Bax was increased significantly (p < 0.05). Moreover, TCNS treatment increased the median survival time of mice bearing glioma to 34 days compared to 22 days in untreated mice.Conclusion: Thus, TCNS treatment significantly inhibits the viability of glioma cells and colony formation, but induces apoptosis and increases the median survival of mice. Hence, TCNS may be of therapeutic value for the treatment of glioma.Keywords: Glioma, Tricyclic neovibsanin scaffold, Survival time, Colony formation, Apoptosi
Peripheral Progenitor Cell Graft in the Rat: A Technique of Graft Processing
The aim of this study was to establish a procedure for blood progenitor cell graft processing in rats. As a first step the mobilization protocol was optimized. The second step was dedicated to define the optimal source for subsequent graft manufacturing: either peripheral blood or spleen. The third step was designed to establish a protocol for purification of stem cells. The best mobilization results in terms of white blood cell count, granulocyte colony forming units (CFUG) and CD90 positive progenitor cells were obtained after pre-treatment of the donors for 5 days with recombinant human granulocyte colony stimulating factor (100 μg/kg) in combination with murine stem cell factor (33 μg/kg). Splenectomy prior to mobilization increased the yield of stem cells from peripheral blood. The numbers of CD90-positive progenitor cells recovered from the spleen of one rat after stem cell mobilization were sufficient to generate one stem cell graft. Grafts containing 1 x 106 progenitor cells – and thus sufficient for transplantation - were obtained after Tcell depletion and positive selection of CD90 positive cells. The grafts were characterized and showed a purity exceeding 70%, a T-cell depletion of 3.6 log10 and a 3-fold increase in CFU-G compared to the yield post mobilization.
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