904 research outputs found
A longitudinal study of influences on alcohol consumption and related harm in Central Australia: with a particular emphasis on the role of price.
Made available by the Northern Territory Library via the Publications (Legal Deposit) Act 2004 (NT).Northern Territory, Department of Health,
Central Australian Aboriginal Congres
Episodic X-ray Emission Accompanying the Activation of an Eruptive Prominence: Evidence of Episodic Magnetic Reconnection
We present an X-ray imaging and spectroscopic study of a partially occulted
C7.7 flare on 2003 April 24 observed by RHESSI that accompanied a prominence
eruption observed by TRACE. (1) The activation and rise of the prominence
occurs during the preheating phase of the flare. The initial X-ray emission
appears as a single coronal source at one leg of the prominence and it then
splits into a double source. Such a source splitting happens three times, each
coinciding with an increased X-ray flux and plasma temperature, suggestive of
fast reconnection in a localized current sheet and an enhanced energy release
rate. In the late stage of this phase, the prominence displays a helical
structure. These observations are consistent with the tether-cutting and/or
kink instability model for triggering solar eruptions. (2) The eruption of the
prominence takes place during the flare impulsive phase. Since then, there
appear signatures predicted by the classical CSHKP model of two-ribbon flares
occurring in a vertical current sheet trailing an eruption. These signatures
include an EUV cusp and current-sheet-like feature (or ridge) above it. There
is also X-ray emission along the EUV ridge both below and above the cusp, which
in both regions appears closer to the cusp at higher energies in the thermal
regime. This trend is reversed in the nonthermal regime. (3) Spectral analysis
indicates thermal X-rays from all sources throughout the flare, while during
the impulsive phase there is additional nonthermal emission which primarily
comes from the coronal source below the cusp. This source also has a lower
temperature, a higher emission measure, and a much harder nonthermal spectrum
than the upper sources.Comment: 8 pages, 5 figures, submitted to Ap
Synergistic interactions of cannabidiol with chemotherapeutic drugs in MCF7 cells : mode of interaction and proteomics analysis of mechanisms
Cannabidiol (CBD), a nonpsychoactive phytocannabinoid, has recently emerged as a potential cytotoxic agent in addition to its ameliorative activity in chemotherapy-associated side effects. In this work, the potential interactions of CBD with docetaxel (DOC), doxorubicin (DOX), paclitaxel (PTX), vinorelbine (VIN), and 7-ethyl-10-hydroxycamptothecin (SN−38) were explored in MCF7 breast adenocarcinoma cells using different synergy quantification models. The apoptotic profiles of MCF7 cells after the treatments were assessed via flow cytometry. The molecular mechanisms of CBD and the most promising combinations were investigated via label-free quantification proteomics. A strong synergy was observed across all synergy models at different molar ratios of CBD in combination with SN−38 and VIN. Intriguingly, synergy was observed for CBD with all chemotherapeutic drugs at a molar ratio of 636:1 in almost all synergy models. However, discording
synergy trends warranted the validation of the selected combinations against different models. Enhanced apoptosis was observed for all synergistic CBD combinations compared to monotherapies or negative controls. A shotgun proteomics study highlighted 121 dysregulated proteins in CBD-treated MCF7 cells compared to the negative controls. We reported the inhibition of topoisomerase II β and α, cullin 1, V-type proton ATPase, and CDK-6 in CBD-treated MCF7 cells for the first time as additional cytotoxic mechanisms of CBD, alongside sabotaged energy production and reduced mitochondrial translation. We observed 91 significantly dysregulated proteins in MCF7 cells treated with the synergistic combination of CBD with SN−38 (CSN−38), compared to the monotherapies. Regulation of telomerase, cell cycle, topoisomerase I, EGFR1, protein metabolism, TP53 regulation
of DNA repair, death receptor signalling, and RHO GTPase signalling pathways contributed to the proteome-wide synergistic molecular mechanisms of CSN−38. In conclusion, we identified significant synergistic interactions between CBD and the five important chemotherapeutic drugs and the key molecular pathways of the combination of CBD and CSN−38 in MCF7 cells. Further in vivo and clinical studies are warranted to evaluate the implementation of CBD-based synergistic adjuvant therapies for breast cancer
Crocins for ischemic stroke : a review of current evidence
Crocins (CRs) and the related active constituents derived from Crocus sativus L. (Saffron) have demonstrated protective effects against cerebral ischemia and ischemic stroke, with various bioactivities including neuroprotection, anti-neuroinflammation, antioxidant, and cardiovascular protection. Among CRs, crocin (CR) has been shown to act on multiple mechanisms and signaling pathways involved in ischemic stroke, including mitochondrial apoptosis, nuclear factor kappa light chain enhancer of B cells pathway, S100 calcium-binding protein B, interleukin-6 and vascular endothelial growth factor-A. CR is generally safe and well-tolerated. Pharmacokinetic studies indicate that CR has poor bioavailability and needs to convert to crocetin (CC) in order to cross the blood-brain barrier. Clinical studies have shown the efficacy of saffron and CR in treating various conditions, including metabolic syndrome, depression, Alzheimer’s disease, and coronary artery disease. There is evidence supporting CR as a treatment for ischemic stroke, although further studies are needed to confirm their efficacy and safety in clinical settings
Endothelium-independent vasodilatory effect of Sailuotong (SLT) on rat isolated tail artery
Background. Sailuotong (SLT) is a standardized three-herb formulation consisting of extracts of Panax ginseng, Ginkgo biloba, and Crocus sativus for the treatment of vascular dementia (VaD). Although SLT has been shown to increase cerebral blood flow, the direct effects of SLT on vascular reactivity have not been explored. (is study aims to examine the vasodilatory effects of SLT and the underlying mechanisms in rat isolated tail artery. Methods. Male (250–300 g) Wistar Kyoto (WKY) rat tail artery was isolated for isometric tension measurement. (e effects of SLT on the influx of calcium through the cell membrane calcium channels were determined in Ca2+-free solution experiments. Results. SLT (0.1–5,000 μg/ml) caused a concentration-dependent relaxation in rat isolated tail artery precontracted by phenylephrine. In the contraction experiments, SLT (500, 1,000, and 5,000 μg/mL) significantly inhibited phenylephrine (0.001 to 10 μM)- and KCl (10–80 mM)-induced contraction, in a concentration-dependent manner. In Ca2+-free solution, SLT (500, 1,000, and 5,000 μg/mL) markedly suppressed Ca2+-induced (0.001–3 mM) vasoconstriction in a concentration-dependent manner in both phenylephrine (10 μM) or KCl (80 mM) stimulated tail arteries. L-type calcium channel blocker nifedipine (10 μM) inhibited PE-induced contraction. Furthermore, SLT significantly reduced phenylephrine-induced transient vasoconstriction in the rat isolated tail artery. Conclusion. SLT induces relaxation of rat isolated tail artery through endothelium-independent mechanisms. (e SLT-induced vasodilatation appeared to be jointly meditated by blockages of extracellular Ca2+ influx via receptor-gated and voltage-gated Ca2+ channels and inhibition of the release of Ca2+ from the sarcoplasmic reticulum
KK Parity in Warped Extra Dimension
We construct models with a Kaluza-Klein (KK) parity in a five- dimensional
warped geometry, in an attempt to address the little hierarchy problem present
in setups with bulk Standard Model fields. The lightest KK particle (LKP) is
stable and can play the role of dark matter. We consider the possibilities of
gluing two identical slices of 5D AdS in either the UV (IR-UV-IR model) or the
IR region (UV-IR-UV model) and discuss the model-building issues as well as
phenomenological properties in both cases. In particular, we find that the
UV-IR-UV model is not gravitationally stable and that additional mechanisms
might be required in the IR-UV-IR model in order to address flavor issues.
Collider signals of the warped KK parity are different from either the
conventional warped extra dimension without KK parity, in which the new
particles are not necessarily pair-produced, or the KK parity in flat universal
extra dimensions, where each KK level is nearly degenerate in mass. Dark matter
and collider properties of a TeV mass KK Z gauge boson as the LKP are
discussed.Comment: 35 pages, 11 figure
Turbulence in the ICM from mergers, cool-core sloshing and jets: results from a new multi-scale filtering approach
We have designed a simple multi-scale method that identifies turbulent
motions in hydrodynamical grid simulations. The method does not assmume ant
a-priori coherence scale to distinguish laminar and turbulent flows. Instead,
the local mean velocity field around each cell is reconstructed with a
multi-scale filtering technique, yielding the maximum scale of turbulent eddies
by means of iterations. The method is robust, fast and easily applicable to any
grid simulation. We present here the application of this technique to the study
of spatial and spectral properties of turbulence in the intra cluster medium,
measuring turbulent diffusion and anisotropy of the turbulent velocity field
for a variety of driving mechanisms: a) accretion of matter in galaxy clusters
(simulated with ENZO); b) sloshing motions around cool-cores (simulated with
FLASH); c) jet outflows from active galactic nuclei, AGN (simulated with
FLASH). The turbulent velocities driven by matter accretion in galaxy clusters
are mostly tangential in the inner regions (inside the cluster virial radius)
and isotropic in regions close to the virial radius. The same is found for
turbulence excited by cool core sloshing, while the jet outflowing from AGN
drives mostly radial turbulence motions near its sonic point and beyond.
Turbulence leads to a diffusivity in the range =10^29-10^30 cm^2/s in the intra
cluster medium. On average, the energetically dominant mechanism of turbulence
driving in the intra cluster medium is represented by accretion of matter and
major mergers during clusters evolution.Comment: 19 pages, 20 figures. Astronomy and Astrophysics, in pres
Phase Space Description of the Leading Order Quark and Gluon Production from a Space-Time Dependent Chromofield
We derive source terms for the production of quarks and gluons from the QCD
vacuum in the presence of a space-time dependent external chromofield A_{cl} to
the order of S^{(1)}. We found that the source terms for the parton production
processes A_{cl} -> q\bar{q} and A_{cl},A_{cl}A_{cl} -> gg also include the
annihilation processes q\bar{q} -> A_{cl} and gg -> A_{cl},A_{cl}A_{cl}. The
source terms we derive are applicable for the description of the production of
partons with momentum p larger rhan gA which itself must be larger than
\Lambda_{QCD}. We observe that these source terms for the production of partons
from a space-time dependent chromofield can be used to study the production and
equilibration of the quark-gluon plasma during the very early stages of an
ultrarelativistic heavy-ion collision.Comment: 30 pages latex (single spaced), 7 eps figures, Revised Version, To
appear in Physical Review
The Temperature of Interstellar Clouds from Turbulent Heating
To evaluate the effect of turbulent heating in the thermal balance of
interstellar clouds, we develop an extension of the log-Poisson intermittency
model to supersonic turbulence. The model depends on a parameter, d,
interpreted as the dimension of the most dissipative structures. By comparing
the model with the probability distribution of the turbulent dissipation rate
in a simulation of supersonic and super-Alfvenic turbulence, we find a best-fit
value of d=1.64. We apply this intermittency model to the computation of the
mass-weighted probability distribution of the gas temperature of molecular
clouds, high-mass star-forming cores, and cold diffuse HI clouds. Our main
results are: i) The mean gas temperature in molecular clouds can be explained
as the effect of turbulent heating alone, while cosmic ray heating may dominate
only in regions where the turbulent heating is low; ii) The mean gas
temperature in high-mass star-forming cores with typical FWHM of ~6 km/s
(corresponding to a 1D rms velocity of 2.5 km/s) may be completely controlled
by turbulent heating, which predicts a mean value of approximately 36 K, two to
three times larger than the mean gas temperature in the absence of turbulent
heating; iii) The intermittency of the turbulent heating can generate enough
hot regions in cold diffuse HI clouds to explain the observed CH+ abundance, if
the rms velocity on a scale of 1 pc is at least 3 km/s, in agreement with
previous results based on incompressible turbulence. Because of its importance
in the thermal balance of molecular clouds and high-mass star-forming cores,
the process of turbulent heating may be central in setting the characteristic
stellar mass and in regulating molecular chemical reactions.Comment: Accepted by ApJ, 15 pages, 7 figure
- …