1,767 research outputs found
4,6-Dimethyl-2-(naphthalen-1-yl)pyrimidine
The asymmetric unit of the title compound, C16H14N2, contains two independent molecules in which the dihedral angles between the pyrimidine and naphthaline rings are 38.20 (5) and 39.35 (5)°. Intermolecular C—H⋯π contacts and π–π stacking interactions [centroid–centroid distances = 3.766 (1) and 3.792 (1) Å] are present in the crystal structure
Streptococcus pneumoniae early response genes to human lung epithelial cells
<p>Abstract</p> <p>Background</p> <p><it>Streptococcus pneumoniae </it>infection starts from colonization of the host respiratory tract where interaction with host respiratory tract epithelial cells occurs. To investigate pneumococcal genes that are involved in the early stage of interaction with host epithelial cells, transcriptional responses of an encapsulated pathogenic pneumococcal strain TIGR4 upon exposure to human lung epithelial cells A549 for 0.5 h and 1 h time periods were investigated by using TIGR (JCVI) microarray technology. Gene expression changes were validated by quantitative real-time PCR (qRT-PCR) analysis.</p> <p>Findings</p> <p>We observed different transcriptional profiles at two incubation time periods in which most gene expressions were down-regulated at 0.5 h but up-regulated at 1 h. Many genes associated with ribonucleotide biosynthesis were down-regulated at both time points, whereas the genes associated with cell envelope, energy metabolism, transport and protein synthesis were mostly up-regulated at 1 h. Furthermore, these profiles were compared to the transcriptomes of a TIGR4-derived strain in response to human macrophages for the same time periods. We found one set of genes that exhibited similar expression changes upon exposure to both types of host cells, including cell envelope-associated <it>bgaA </it>(SP0648) and <it>nanA </it>(SP1693), and uncharacterized gene clusters such as SP1677–SP1680 and SP1688–SP1690.</p> <p>Conclusion</p> <p>These data indicate that at the early stage of interaction with host epithelial cells, a complex gene regulation and expression change occur in bacteria. Some of them might play an essential role during pathogen-host interactions and for the establishment of infection.</p
2,2′-(p-Phenylene)bis(4,5-dihydro-1H-imidazol-3-ium) bis(3-nitrobenzoate)
In the title compound, C12H16N4
+·2C7H4NO4
−, the complete 2,2′-(p-phenylene)bis(4,5-dihydro-1H-imidazol-3-ium) (bib) dication is generated by crystallographic inversion symmetry. The bib cations reside on crystallographic inversion centers, which coincide with the centroids of the respective benzene rings. In the cation, the imidazole ring adopts an envelop conformation with the flap atom displaced by 0.082 (3) Å from the plane through the other ring atoms. In the crystal, the cations and anions are linked through intermolecular N—H⋯O hydrogen bonds, forming chains running along the a axis. C—H⋯O interactions also occur. Weak π–π contacts between the imidazole rings of bib and between the benzene rings of NB [centroid–centroid distances = 3.501 (1) and 3.281 (2) Å, respectively] may further stabilize the structure
Study on Roadway Parameters of Broken Compound Roof of Gently Inclined Thick Coal Seam
AbstractThis paper through investigation of the geological conditions of Da’ Anshan's coal mine, according to the special of the broken compound roof on inclined thick coal seam, select the anchor suspension theory and composite beam theory, design the roadway support's anchor parameters, and apply the finite element software ADINA carry out simulation analysis, through the contrast of analysis and engineering data, proved that the design of support parameters is reasonably and practicable. The research has practical value and can guide similar projects
County-level CO2 emissions and sequestration in China during 1997–2017
With the implementation of China’s top-down CO2 emissions reduction strategy, the regional differences should be considered. As the most basic governmental unit in China, counties could better capture the regional heterogeneity than provinces and prefecture-level city, and county-level CO2 emissions could be used for the development of strategic policies tailored to local conditions. However, most of the previous accounts of CO2 emissions in China have only focused on the national, provincial, or city levels, owing to limited methods and smaller-scale data. In this study, a particle swarm optimization-back propagation (PSO-BP) algorithm was employed to unify the scale of DMSP/OLS and NPP/VIIRS satellite imagery and estimate the CO2 emissions in 2,735 Chinese counties during 1997–2017. Moreover, as vegetation has a significant ability to sequester and reduce CO2 emissions, we calculated the county-level carbon sequestration value of terrestrial vegetation. The results presented here can contribute to existing data gaps and enable the development of strategies to reduce CO2 emissions in China
Caffeic Acid Phenethyl Ester (CAPE) mediated decrease in metastasis of colon cancer cells: an in vitro and in vivo study
Background: Caffeic acid phenethyl ester (CAPE) is a phytochemically active component obtained from honeybee hive propolis. CAPE has been reported to show antimitogenic, anticancer, and other beneficial medicinal properties. Many of its activities have been reported to be mediated by inhibiting levels of matrix metalloproteinase, that is, MMP-2 and MMP-9. We hypothesize the effect of CAPE on the metastasis of colon cancer cells in both in vitro and in vivo.Methods: Cell migration, motility, invasion were evaluated also expression of protein and matrix metalloproteinases (MMPs) such as MMP-2 and MMP-9 were measured in SW-480 cancer cells in vitro. The cells were exposed to Phorbol 12-myristate 13-acetate (PMA) and were treated with various concentration of CAPE.Results: The treatment of CAPE caused significant decrease (P<0.05) in both cell motility and invasion. The treatment of CAPE inhibited activity of MMP-2 and MMP-9 and their protein with increasing dose in SW-480 cancerous cells. Antimetastatic activity was evaluated in vivo in BALB/c mice by injecting them with CT-26 mouse colon cancer cells via tail vein and were treated with CAPE (20 mg/kg) orally for 21 days. The CAPE treatment significantly (P<0.05) reduced count of pulmonary nodules. The mice showed decreased plasma MMP-2 and MMP-9 activity after 21 days treatment with CAPE.Conclusion: The study suggested beneficial role of CAPE in preventing invasion of colon cancer and metastasis via MMP- 2 and MMP-9 mediated pathway.Keywords: CAPE, colon cancer, SW-480, CT-26, anti-metastati
Spin waves and magnetic exchange interactions in the spin ladder compound RbFeSe
We report an inelastic neutron scattering study of the spin waves of the
one-dimensional antiferromagnetic spin ladder compound RbFeSe. The
results reveal that the products, 's, of the spin and the magnetic
exchange interactions 's along the antiferromagnetic (leg) direction and the
ferromagnetic (rung) direction are comparable with those for the stripe ordered
phase of the parent compounds of the iron-based superconductors. The
universality of the 's implies nearly universal spin wave dynamics and the
irrelevance of the fermiology for the existence of the stripe antiferromagnetic
order among various Fe-based materials.Comment: 6 pages, 4 figure
Resonant cyclotron scattering in pulsar magnetospheres and its application to isolated neutron stars
Resonant cyclotron scattering (RCS) in pulsar magnetospheres is considered.
The photon diffusion equation (Kompaneets equation) for RCS is derived. The
photon system is modeled three dimensionally. Numerical calculations show that
there exist not only up scattering but also down scattering of RCS, depending
on the parameter space. RCS's possible applications to the spectra energy
distributions of magnetar candidates and radio quiet isolated neutron stars
(INSs) are point out. The optical/UV excess of INSs may caused by the down
scattering of RCS. The calculations for RX J1856.5-3754 and RX J0720.4-3125 are
presented and compared with their observational data. In our model, the INSs
are proposed to be normal neutron stars, although the quark star hypothesis is
still possible. The low pulsation amplitude of INSs is a natural consequence in
the RCS model.Comment: 16 pages, 5 figures, 2 tables, accepted for publication in RA
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