366 research outputs found
On the relation between the mass of Compact Massive Objects and their host galaxies
Supermassive black holes and/or very dense stellar clusters are found in the
central regions of galaxies. Nuclear star clusters are present mainly in faint
galaxies while upermassive black holes are common in galaxies with masses M. In the intermediate galactic mass range both types of
central massive objects (CMOs) are found. Here we present our collection of a
huge set of nuclear star cluster and massive black hole data that enlarges
significantly already existing data bases useful to investigate for
correlations of their absolute magnitudes, velocity dispersions and masses with
structural parameters of their host galaxies. In particular, we directed our
attention to some differences between the correlations of nuclear star clusters
and massive black holes as subsets of CMOs with hosting galaxies. In this
context, the mass-velocity dispersion relation plays a relevant role because it
seems the one that shows a clearer difference between the supermassive black
holes and nuclear star clusters. The has a slope of while has the much smaller slope of .
The slopes of the CMO mass- host galaxy B magnitude of the two types of CMOs
are indistinguishable within the errors while that of the NSC mass-host galaxy
mass relation is significantly smaller than for supermassive black holes.
Another important result is the clear depauperation of the NSC population in
bright galaxy hosts, which reflects also in a clear flattening of the NSC mass
vs host galaxy mass at high host masses.Comment: 12 pages, 22 figures, 2 tables, accepted for publication in MNRA
Chain or Ring: Which One Is Favorable in Nitrogen-Rich Molecules N<sub>6</sub>XH<i><sub>m</sub></i>, N<sub>8</sub>XH<i><sub>m</sub></i>, and N<sub>10</sub>XH<i><sub>m</sub></i> (X = B, Al, Ga, <i>m</i> = 1 and X = C, Si, Ge, <i>m</i>Â =Â 2)?
A series of nitrogen-rich molecules
N<sub>6</sub>XH<sub><i>m</i></sub>, N<sub>8</sub>XH<sub><i>m</i></sub>, and
N<sub>10</sub>XH<sub><i>m</i></sub> (X = B, Al, Ga, <i>m</i> = 1 and X = C, Si, Ge, <i>m</i> = 2) consisting
of N<sub>3</sub> and N<sub>5</sub> radicals, are systematically investigated
by using B3LYP and B3PW91 DFT methods. It is found that for the nitrogen-rich
molecules, the structures with N<sub>3</sub>-chains (N<sub>5</sub>-ring) are more stable than those containing a N<sub>3</sub>-ring
(N<sub>5</sub>-chain). This result could be well-explained by the
intrinsic stability of the N<sub>3</sub> and N<sub>5</sub> radicals
and their charge distribution in nitrogen-rich molecules. The dissociation
energies further indicate that the B-doped and C-doped structures
are the most stable among the molecules with three elements of group
13 and 14, respectively. Energy decomposition analysis shows the bond
of boron–nitrogen is stronger than that of carbon–nitrogen.
Detailed bonding analysis demonstrates that the B–N bond is
determined by σ and π interactions between the B and N
atoms, whereas C–N bonds by only σ interactions. These
results imply that the boron atom is more suitable than the carbon
atom for building the nitrogen-rich molecules studied in this article
Cell Number Expansion analysis of MES and MEF cells after five days incubation under 1G or SMG.
<p>(A) The initial MES cells seeding number was 3×10<sup>4</sup>. The cell doubling curve was generated by dividing the cell number by10<sup>4</sup> and then transforming the values to logarithm base2. (B) The initial MEF cells seeding number was 10<sup>5</sup>. The cell doubling curve was generated by dividing the cell number by10<sup>4</sup> and then transforming the values to logarithm base2. The data represent mean ±SD of three independent experiments.</p
Effects of SMG on NADPH oxidase2 (Nox2) expression in <i>Mdc1</i><sup><i>+/+</i></sup> and <i>Mdc1</i><sup><i>-/-</i></sup> MEF cells.
<p>(A) Western blot analysis of Nox2 protein expression in <i>Mdc1</i><sup><b><i>+/+</i></b></sup> and <i>Mdc1</i><sup><b><i>-/-</i></b></sup> MEF cells exposed to 1G or SMG condition for 1 or 5days. GAPDH was used as an internal control. The representative results of three independent experiments were shown. (B) Quantitative comparison of Nox2 expression. Data were derived from three independent experiments as in A). The expression levels of Nox2 were normalized to the endogenous control GAPDH expression. The data represent mean ± SD of three independent experiments. Student’s t test, *P<0.05.</p
Effects of SMG on antioxidant enzyme activity in MES cells.
<p><i>Rad9</i><sup><b><i>+/+</i></b></sup> MES cells and <i>Rad9</i><sup><b><i>-/-</i></b></sup> MES cells were cultured under 1G and SMG for 1 and 5 days, respectively. The activities of the antioxidant enzymes in MES cell lysates were determined. (A) Histograms of superoxide dismutase enzyme activity. (B) Histograms of catalase enzyme activity. (C) Histogram of Glutahione peroxidase. The data represent mean ± SD of three independent experiments.</p
Effects of SMG on DNA damage in <i>Mdc1</i><sup><i>+/+</i></sup> and <i>Mdc1</i><sup><i>-/-</i></sup> MEF cells.
<p>Evaluation of DNA double strand break by neutral comet assay in <i>Mdc1</i><sup><b><i>+/+</i></b></sup> and <i>Mdc1</i><sup><b><i>-/-</i></b></sup> MEF cells cultured under 1G or SMG condition for 1 or 5 days. At least 50 cells for each condition were scored for comet tail moment. The data represent mean ± SD of three independent experiments. Student’s t test, *P<0.05.</p
Chemical Sensing on a Single SERS Particle
We report a new chemical
sensing platform on a single surface-enhanced
Raman scattering (SERS) particle. A cabbage-like Au microparticle
(CLMP) with high SERS enhancement was applied as an ultrasensitive
SERS substrate. A new Raman reporter bisÂ[4,4′-[dithiodiphenyl
azo-phenol] (DTDPAP) was synthesized to display multiple fingerprints
and high reactivity toward sodium dithionite. The reaction of DTDPAP
with sodium dithionite was in situ monitored by SERS on a single CLMP.
The DTDPAP fingerprint change is dependent on the sodium dithionite
concentration, providing a simple and sensitive method for sodium
dithionite profiling
Effects of SMG on DNA damage and apoptosis in <i>Rad9</i><sup><i>+/+</i></sup> and <i>Rad9</i><sup><i>-/-</i></sup> MES cells.
<p>(A) Evaluation of DNA double strand break by neutral comet assay in <i>Rad9</i><sup><b><i>+/+</i></b></sup> and <i>Rad9</i><sup><b><i>-/-</i></b></sup> MES cells cultured under 1G or SMG condition. Time points were 1, 2, 3, 4 and 5 days. At least 50 cells for each condition were scored for comet tail moment. (B) Flow cytometric analysis of γ-H2AX formation in <i>Rad9</i><sup><b><i>+/+</i></b></sup> and <i>Rad9</i><sup><b><i>-/-</i></b></sup> mMES cells cultured under 1G or SMG condition for 1 or 5 days. (C) Evaluation of DNA damage by alkaline comet assay in <i>Rad9</i><sup><b><i>+/+</i></b></sup> and <i>Rad9</i><sup><b><i>-/-</i></b></sup> MES cells cultured under 1G or SMG condition for 1 or 5 days. At least 50 cells for each condition were scored for comet tail moment. (D) Evaluation of DNA damage by alkaline comet assay in <i>Rad9</i><sup><b><i>-/-</i></b></sup> MES cells with ectopic expression of <i>Rad9</i> (<i>Rad9</i><sup><b><i>-/-</i></b></sup><i>+Rad9</i> MES cells) cultured under 1G or SMG condition for 1 or 5 days. At least 50 cells for each condition were scored for comet tail moment. (E) Flow cytometric analysis of <i>Rad9</i><sup><b><i>+/+</i></b></sup> and <i>Rad9</i><sup><b><i>-/-</i></b></sup> MES cells cultured under 1G or SMG condition for 1 day to assess apoptosis using Annexin V labeling. Experiments were performed three times and representative analyses are shown (upper). The lower part is the quantitative comparison of apoptosis between the 1G Group and the SMG Group. The data represent mean ± SD of at least three independent experiments. Student’s t test, *P<0.05.</p
Characterizing Binding of Small Molecules. II. Evaluating the Potency of Small Molecules to Combat Resistance Based on Docking Structures
Drug
resistance severely erodes the efficacy of therapeutic treatments
for many diseases. Assessing the potency of a drug lead to combat
resistance is no doubt critical for designing new drugs or new therapeutic
combinations. Virtual screening is often the first step in drug discovery
and a challenging problem is to accurately predict the resistant profile
of an inhibitor based on the docking structures. Using a well studied
system HIV-1 protease, we have illustrated the success of a computational
method called MIEC-SVM on tackling this problem. We computed molecular
interaction energy components (MIECs) between the ligand and the protease
residues to characterize the docking poses, which were input to support
vector machine (SVM) to distinguish resistant from nonresistant mutants.
More importantly, the method is able to predict resistant profiles
for new drugs based on the docking structures as indicated by its
satisfactory performance in leave-one-drug-out and leave-drug/mutants-out
tests. Therefore, the MIEC-SVM method can also facilitate designing
effective therapeutic combinations by combining drugs with complementary
resistant profiles
Effects of SMG on NADPH oxidase2 (Nox2) and NADPH oxidase4 (Nox4) expression in <i>Rad9</i><sup><i>+/+</i></sup> and <i>Rad9</i><sup><i>-/-</i></sup> MES cells.
<p>(A) Quantitative real-time PCR analysis of Nox2 mRNA expression in <i>Rad9</i><sup><b><i>+/+</i></b></sup> and <i>Rad9</i><sup><b><i>-/-</i></b></sup> MES cells exposed to 1G or SMG condition for 1 or 5 days. The expression levels of Nox2 were normalized to the endogenous control GAPDH expression. (B) Quantitative real-time PCR analysis of Nox4 mRNA expression in <i>Rad9</i><sup><b><i>+/+</i></b></sup> and <i>Rad9</i><sup><b><i>-/-</i></b></sup> MES cells exposed to 1G or SMG condition for 1 or 5 days. The expression levels of Nox4 were normalized to the endogenous control GAPDH expression. (C) Western blot analysis of Nox2 protein expression in <i>Rad9</i><sup><b><i>+/+</i></b></sup> and <i>Rad9</i><sup><b><i>-/-</i></b></sup> MES cells exposed to 1G or SMG condition for 1 or 5 days. GAPDH was used as an internal control. The representative results of three independent experiments were shown. (D) Quantitative comparison of Nox2 expression. Data were derived from three independent experiments. The expression levels of Nox2 protein were normalized to the endogenous control GAPDH protein expression. The data represent mean ± SD of three independent experiments. Student’s t test, *P<0.05.</p
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