2,607 research outputs found
Genetically engineered pre-microRNA-34a prodrug suppresses orthotopic osteosarcoma xenograft tumor growth via the induction of apoptosis and cell cycle arrest.
Osteosarcoma (OS) is the most common primary malignant bone tumor in children, and microRNA-34a (miR-34a) replacement therapy represents a new treatment strategy. This study was to define the effectiveness and safety profiles of a novel bioengineered miR-34a prodrug in orthotopic OS xenograft tumor mouse model. Highly purified pre-miR-34a prodrug significantly inhibited the proliferation of human 143B and MG-63 cells in a dose dependent manner and to much greater degrees than controls, which was attributed to induction of apoptosis and G2 cell cycle arrest. Inhibition of OS cell growth and invasion were associated with release of high levels of mature miR-34a from pre-miR-34a prodrug and consequently reduction of protein levels of many miR-34a target genes including SIRT1, BCL2, c-MET, and CDK6. Furthermore, intravenous administration of in vivo-jetPEI formulated miR-34a prodrug significantly reduced OS tumor growth in orthotopic xenograft mouse models. In addition, mouse blood chemistry profiles indicated that therapeutic doses of bioengineered miR-34a prodrug were well tolerated in these animals. The results demonstrated that bioengineered miR-34a prodrug was effective to control OS tumor growth which involved the induction of apoptosis and cell cycle arrest, supporting the development of bioengineered RNAs as a novel class of large molecule therapeutic agents
Memory effect and multifractality of cross-correlations in financial markets
An average instantaneous cross-correlation function is introduced to quantify
the interaction of the financial market of a specific time. Based on the daily
data of the American and Chinese stock markets, memory effect of the average
instantaneous cross-correlations is investigated over different price return
time intervals. Long-range time-correlations are revealed, and are found to
persist up to a month-order magnitude of the price return time interval.
Multifractal nature is investigated by a multifractal detrended fluctuation
analysis.Comment: 11 pages, 4 figures
Dynamics of Bid-ask Spread Return and Volatility of the Chinese Stock Market
Bid-ask spread is taken as an important measure of the financial market
liquidity. In this article, we study the dynamics of the spread return and the
spread volatility of four liquid stocks in the Chinese stock market, including
the memory effect and the multifractal nature. By investigating the
autocorrelation function and the Detrended Fluctuation Analysis (DFA), we find
that the spread return is lack of long-range memory, while the spread
volatility is long-range time correlated. Moreover, by applying the
Multifractal Detrended Fluctuation Analysis (MF-DFA), the spread return is
observed to possess a strong multifractality, which is similar to the dynamics
of a variety of financial quantities. Differently from the spread return, the
spread volatility exhibits a weak multifractal nature
Colorectal cancer screening with fecal occult blood test: A 22-year cohort study.
The aim of the present study was to investigate the efficacy of colorectal cancer (CRC) screening with a three-tier fecal occult blood test (FOBT) in the Chinese population. The study was performed between 1987 and 2008 at the Beijing Military General Hospital, in a cohort of army service males and females aged >50 years. Between 1987 and 2005, a three-tier screening program, comprising guaiac-based FOBTs (gFOBTs), followed by immunochemical FOBTs for positive guaiac test samples and then colonoscopy for positive immunochemical test subjects, was performed annually. The cohort was followed up until 2008. The cohort included 5,104 subjects, of which, 3,863 subjects participated in screening (screening group) and 1,241 did not (non-screening group). The two groups did not differ in age, gender or other major risk factors for colon cancer. Overall, 36 CRCs occurred in the screening group and 21 in the non-screening group. Compared with the non-screening group, the relative risk for the incidence and mortality of CRC was 0.51 [95% confidence interval (CI), 0.30-0.87] and 0.36 (95% CI, 0.18-0.71), respectively, in the screening group. The general sensitivity of this three-tier FOBT was 80.6% (95% CI, 65.3-91.1). Thus, annual screening using the three-tier FOBT program may reduce the CRC incidence and mortality rate
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
Elliptical Galaxies with Emission Lines from the Sloan Digital Sky Survey
We present the results of 11 elliptical galaxies with strong nebular emission
lines during our study of star formation history along the Hubble sequence.
After removing the dilution from the underlying old stellar populations by use
of stellar population synthesis model, we derive the accurate fluxes of all
emission lines for these objects, which are later classified with emission line
ratios into one Seyfert 2, six LINERs and four HII galaxies. We also identify
one HII galaxy (A1216+04) as a hitherto unknown Wolf-Rayet galaxy from the
presence of the Wolf-Rayet broad bump at 4650 \AA. We propose that the
star-forming activities in elliptical galaxies are triggered by either
galaxy-galaxy interaction or the merging of a small satellite/a massive star
cluster, as already suggested by recent numerical simulations
The quasar SDSS J142507.32+323137.4 : dual AGNs?
We analyze the optical spectrum of type 1 QSO SDSS J1425+3231. This ob- ject
is interesting since its narrow emission lines such as [O
III]{\lambda}{\lambda}4959, 5007 are double- peaked, and the line structure can
be modeled well by three Gaussian components: two components for the two peaks
(we refer the peaks at low/high redshift as "the blue/red component") and
another one for the line wing which has the same line center as that of the
blue component, but ~ 3 times broader. The separation between the blue and red
components is ~ 500 km/s with blue component ~ 2 times broader than the red
one. The H{\beta} emission can be separated into four components: two for the
double-peaked narrow line and two for the broad line which comes from the broad
line region (BLRs). The black hole mass estimated from the broad H{\beta}
emission line using the typical reverberation map- ping relation is 0.85 \times
108M\odot, which is consistent with that derived from parameters of [O
III]{\lambda} 5007 of the blue component. We suggest this QSO might be a dual
AGN system, the broad H{\beta} emission line is mainly contributed by the
primary black hole (traced by the blue component) while the broad H{\beta}
component of the secondary black hole (traced by the red component) is hard to
be separated out considering a resolution of ~2000 of SDSS spectra or it is
totally obscured by the dusty torus.Comment: 9 pages, 2 figures, accepted for publication in RA
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Revealing of the Activation Pathway and Cathode Electrolyte Interphase Evolution of Li-Rich 0.5Li2MnO3·0.5LiNi0.3Co0.3Mn0.4O2 Cathode by in Situ Electrochemical Quartz Crystal Microbalance.
The first-cycle behavior of layered Li-rich oxides, including Li2MnO3 activation and cathode electrolyte interphase (CEI) formation, significantly influences their electrochemical performance. However, the Li2MnO3 activation pathway and the CEI formation process are still controversial. Here, the first-cycle properties of xLi2MnO3·(1- x) LiNi0.3Co0.3Mn0.4O2 ( x = 0, 0.5, 1) cathode materials were studied with an in situ electrochemical quartz crystal microbalance (EQCM). The results demonstrate that a synergistic effect between the layered Li2MnO3 and LiNi0.3Co0.3Mn0.4O2 structures can significantly affect the activation pathway of Li1.2Ni0.12Co0.12Mn0.56O2, leading to an extra-high capacity. It is demonstrated that Li2MnO3 activation in Li-rich materials is dominated by electrochemical decomposition (oxygen redox), which is different from the activation process of pure Li2MnO3 governed by chemical decomposition (Li2O evolution). CEI evolution is closely related to Li+ extraction/insertion. The valence state variation of the metal ions (Ni, Co, Mn) in Li-rich materials can promote CEI formation. This study is of significance for understanding and designing Li-rich cathode-based batteries
Twist1 enhances hypoxia induced radioresistance in cervical cancer cells by promoting nuclear EGFR localization
Twist1 is a crucial transcription factor that regulates epithelial mesenchymal transition and involves in metastasis. Recent evidence suggests that Twist1 plays important role in hypoxia-induced radioresistance, but the underlying mechanism remains elusive. Here we investigated the change of Twist1 expression in human cervical squamous cancer cell line SiHa after hypoxia treatment. We also explored the role of Twist1 in radioresistance by manipulating the expression level of Twist1.We observed that hypoxia treatment elevated the expression of Twist1 in SiHa cells. Knockdown of Twist1 with siRNA increased the radiosensitivity of SiHa cells under hypoxia condition, accompanied by reduced levels of nuclear Epidermal Growth Factor Receptor (EGFR) and DNA-dependent protein kinase (DNA-PK). Conversely, overexpression of Twist1 led to increased radioresistance of SiHa cells, which in turn increased nuclear EGFR localisation and expression levels of nuclear DNA-PK. Moreover, concomitant high expression of hypoxia-inducible factor-1? (HIF-1?) and Twist1 in primary tumors of cervical cancer patients correlated with the worse prognosis after irradiation treatment. Taken together, these data provide new insights into molecular mechanism underlying hypoxia-induced radio resistance in cervical cancer cells, and suggest that Twist1 is a promising molecular target to improve the efficacy of cancer radiotherapy
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