15,176 research outputs found
Inhibition effects of paeonol on mice bearing EMT6 breast cancer through inducing rumor cell apoptosis
Paeonol, a phenolic component from the root bark of Paeonia moutan, has been identified to
possess antitumor effects on mice bearing EMT6 breast cancer in our previous studies. However, the underlying mechanisms remain unknown. In the present study the molecular mechanisms of paeonol were
further investigated in EMT6 mice model. The results showed that treatment of mice with 175 and 350
mg/kg/day of paeonol significantly inhibited the growth of the EMT6 tumor in mice, and induced tumor
cell apoptosis which were demonstrated by light microscopy after hematoxylin and eosin staining and
apoptosis analysis by flow cytometry. In addition, compared with the control group, paeonol increased the
number of tumor cells in G0/G1 phase but decreased the number of cells in S and G2/M phase. Paeonol
treatment (350 mg/kg body weight) also resulted in a decrease of Bcl-2 and an increase in Bax and caspase-3 expressions, which were demonstrated by immunohistochemical and western blot analysis. These
results indicate that the antitumor effects of paeonol might be associated with arresting tumor cells in the
G0/G1 phase, inducing cell apoptosis and regulation of the expression of Bcl-2, Bax and activation of caspase-3
Antitumor effect of salidroside on mice bearing HepA hepatocellular carcinoma
Salidroside, a phenylpropanoid glycoside extracted from Rhodiola rosea L., has antiproliferative effects on tumour cells in mice. However it’s antitumor mechanism remains largely unknown. In this study, 4 groups of mice bearing hepatocarcinoma cells were given treatment with vehicle alone, cyclophosphamide (25 mg/kg, i.p.) and salidroside, either 100 or 200 mg/kg (p.o.) for 14 days. The morphology of tumour specimens was analysed by transmission electron microscopy. Apoptotic cells in sections of mouse tumour tissue were analysed using an in situ apoptosis kit. The expression of Bcl-2, Bax and caspase 3 mRNA were examined with RT-PCR. The results showed that the tumour weights in groups 100 or 200 mg/kg/day of salidroside were reduced significantly (45.34 and 52.48% respectively), compared to vehicle groups. Salidroside increased apoptotic cells index, e.g. in 200 mg/kg group, it was four times higher compared to the control group. Even more, treatment with salidroside decreased Bcl-2 mRNA expression and increased Bax and caspase 3 mRNA expressions. These indicated that the antitumor mechanism of salidroside may induce tumour cell apoptosis in mice by triggering the mitochondrial-dependent pathway and activation of caspase 3
The macroeconomic and financial effects of oil price shocks
The oil price shock is considered as a major contributor to economic fluctuation. In this paper, we investigate whether the impulse responses of different macroeconomic variables and financial variables to the oil price shock and the effect of interest rates change. And we also use Granger Causality Test to evaluate the correlation between oil prices, stock markets and gold prices. Estimation results based on the U.S. data suggest that: (i) The oil price shock has a significant impact on inflation, stock markets and gold prices and it also has a short-term impact on interest rates. (ii) Co-movement of oil prices, stock markets and gold prices exist. (iii) Changing interest rates as monetary policy can induce price puzzle in order to reduce the inflation caused by the oil price shock
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Analysis of interspecies adherence of oral bacteria using a membrane binding assay coupled with polymerase chain reaction-denaturing gradient gel electrophoresis profiling.
Information on co-adherence of different oral bacterial species is important for understanding interspecies interactions within oral microbial community. Current knowledge on this topic is heavily based on pariwise coaggregation of known, cultivable species. In this study, we employed a membrane binding assay coupled with polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) to systematically analyze the co-adherence profiles of oral bacterial species, and achieved a more profound knowledge beyond pairwise coaggregation. Two oral bacterial species were selected to serve as "bait": Fusobacterium nucleatum (F. nucleatum) whose ability to adhere to a multitude of oral bacterial species has been extensively studied for pairwise interactions and Streptococcus mutans (S. mutans) whose interacting partners are largely unknown. To enable screening of interacting partner species within bacterial mixtures, cells of the "bait" oral bacterium were immobilized on nitrocellulose membranes which were washed and blocked to prevent unspecific binding. The "prey" bacterial mixtures (including known species or natural saliva samples) were added, unbound cells were washed off after the incubation period and the remaining cells were eluted using 0.2 mol x L(-1) glycine. Genomic DNA was extracted, subjected to 16S rRNA PCR amplification and separation of the resulting PCR products by DGGE. Selected bands were recovered from the gel, sequenced and identified via Nucleotide BLAST searches against different databases. While few bacterial species bound to S. mutans, consistent with previous findings F. nucleatum adhered to a variety of bacterial species including uncultivable and uncharacterized ones. This new approach can more effectively analyze the co-adherence profiles of oral bacteria, and could facilitate the systematic study of interbacterial binding of oral microbial species
Evolution of worldwide stock markets, correlation structure and correlation based graphs
We investigate the daily correlation present among market indices of stock
exchanges located all over the world in the time period Jan 1996 - Jul 2009. We
discover that the correlation among market indices presents both a fast and a
slow dynamics. The slow dynamics reflects the development and consolidation of
globalization. The fast dynamics is associated with critical events that
originate in a specific country or region of the world and rapidly affect the
global system. We provide evidence that the short term timescale of correlation
among market indices is less than 3 trading months (about 60 trading days). The
average values of the non diagonal elements of the correlation matrix,
correlation based graphs and the spectral properties of the largest eigenvalues
and eigenvectors of the correlation matrix are carrying information about the
fast and slow dynamics of correlation of market indices. We introduce a measure
of mutual information based on link co-occurrence in networks, in order to
detect the fast dynamics of successive changes of correlation based graphs in a
quantitative way.Comment: 8 pages, 11 figure
Kondo Phase in Twisted Bilayer Graphene -- A Unified Theory for Distinct Experiments
A number of interesting physical phenomena have been discovered in
magic-angle twisted bilayer graphene (MATBG), such as superconductivity,
correlated gapped and gapless phases, etc. The gapped phases are believed to be
symmetry-breaking states described by mean-field theories, whereas gapless
phases exhibit features beyond mean field. This work, combining poor man's
scaling, numerical renormalization group, and dynamic mean-field theory,
demonstrates that the gapless phases are the heavy Fermi liquid state with some
symmetries broken and the others preserved. We adopt the recently proposed
topological heavy fermion model for MATBG with effective local orbitals around
AA-stacking regions and Dirac fermions surrounding them. At zero temperature
and most non-integer fillings, the ground states are found to be heavy Fermi
liquids and exhibit Kondo resonance peaks. The Kondo temperature is found
at the order of 1meV. A higher temperature than will drive the system
into a metallic LM phase where disordered LM's and a Fermi liquid coexist. At
integer fillings , is suppressed to zero or a value weaker
than RKKY interaction, leading to Mott insulators or symmetry-breaking states.
This theory offers a unified explanation for several experimental observations,
such as zero-energy peaks and quantum-dot-like behaviors in STM, the
Pomeranchuk effect, and the saw-tooth feature of inverse compressibility, etc.
For future experimental verification, we predict that the Fermi surface in the
gapless phase will shrink upon heating - as a characteristic of the heavy Fermi
liquid. We also conjecture that the heavy Fermi liquid is the parent state of
the observed unconventional superconductivity because the Kondo screening
reduces the overwhelming Coulomb interaction (~60meV) to a rather small
effective interaction (~1meV) comparable to possible weak attractive
interactions.Comment: DMFT calculations for the THF model and discussions on possible
symmetry-breaking states are adde
A Performance Analysis Model of TCP over Multiple Heterogeneous Paths for 5G Mobile Services
Driven by the primary requirement of emerging 5G mobile services, the demand
for concurrent multipath transfer (CMT) is still prominent. Yet, multipath
transport protocols are not widely adopted and TCP-based CMT schemes will still
be in dominant position in 5G. However, the performance of TCP flow transferred
over multiple heterogeneous paths is prone to the link quality asymmetry, the
extent of which was revealed to be significant by our field investigation. In
this paper, we present a performance analysis model for TCP over multiple
heterogeneous paths in 5G scenarios, where both bandwidth and delay asymmetry
are taken into consideration. The evaluation adopting parameters from field
investigation shows that the proposed model can achieve high accuracy in
practical environments. Some interesting inferences can be drawn from the
proposed model, such as the dominant factor that affect the performance of TCP
over heterogeneous networks, and the criteria of determining the appropriate
number of links to be used under different circumstances of path heterogeneity.
Thus, the proposed model can provide a guidance to the design of TCP-based CMT
solutions for 5G mobile services
Friction-induced nanofabrication method to produce protrusive nanostructures on quartz
In this paper, a new friction-induced nanofabrication method is presented to fabricate protrusive nanostructures on quartz surfaces through scratching a diamond tip under given normal loads. The nanostructures, such as nanodots, nanolines, surface mesas and nanowords, can be produced on the target surface by programming the tip traces according to the demanded patterns. The height of these nanostructures increases with the increase of the number of scratching cycles or the normal load. Transmission electron microscope observations indicated that the lattice distortion and dislocations induced by the mechanical interaction may have played a dominating role in the formation of the protrusive nanostructures on quartz surfaces. Further analysis reveals that during scratching, a contact pressure ranged from 0.4Py to Py (Py is the critical yield pressure of quartz) is apt to produce protuberant nanostructures on quartz under the given experimental conditions. Finally, it is of great interest to find that the protrusive nanostructures can be selectively dissolved in 20% KOH solution. Since the nanowords can be easily 'written' by friction-induced fabrication and 'erased' through selective etching on a quartz surface, this friction-induced method opens up new opportunities for future nanofabrication
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