1,323 research outputs found
Energy levels and radiative rates for transitions in Ti VII
We report calculations of energy levels, radiative rates, oscillator
strengths and line strengths for transitions among the lowest 231 levels of Ti
VII. The general-purpose relativistic atomic structure package ({\sc grasp})
and flexible atomic code ({\sc fac}) are adopted for the calculations.
Radiative rates, oscillator strengths and line strengths are provided for all
electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2) and
magnetic quadrupole (M2) transitions among the 231 levels, although
calculations have been performed for a much larger number of levels (159,162).
In addition, lifetimes for all 231 levels are listed. Comparisons are made with
existing results and the accuracy of the data is assessed. In particular, the
most recent calculations reported by Singh {\em et al} [Can J. Phys. {\bf 90}
(2012) 833] are found to be unreliable, with discrepancies for energy levels of
up to 1 Ryd and for radiative rates of up to five orders of magnitude for
several transitions, particularly the weaker ones. Based on several comparisons
among a variety of calculations with two independent codes, as well as with the
earlier results, our listed energy levels are estimated to be accurate to
better than (within 0.1 Ryd), whereas results for radiative rates and
other related parameters should be accurate to better than .Comment: Text 11p, Tables 6, to appear in Physica Scripta 88 (2013) XXX. arXiv
admin note: substantial text overlap with arXiv:1307.2732, arXiv:1307.247
Energy levels, radiative rates and electron impact excitation rates for transitions in Si II
Energies for the lowest 56 levels, belonging to the 3s3p, 3s3p,
3p, 3s3d, 3s3p3d, 3s4 and 3s5 configurations of Si
II, are calculated using the {\sc grasp} (General-purpose Relativistic Atomic
Structure Package) code. Analogous calculations have also been performed (for
up to 175 levels) using the Flexible Atomic Code ({\sc fac}). Furthermore,
radiative rates are calculated for all E1, E2, M1 and M2 transitions. Extensive
comparisons are made with available theoretical and experimental energy levels,
and the accuracy of the present results is assessed to be better than 0.1 Ryd.
Similarly, the accuracy for radiative rates (and subsequently lifetimes) is
estimated to be better than 20% for most of the (strong) transitions. Electron
impact excitation collision strengths are also calculated, with the Dirac
Atomic R-matrix Code ({\sc darc}), over a wide energy range up to 13 Ryd.
Finally, to determine effective collision strengths, resonances are resolved in
a fine energy mesh in the thresholds region. These collision strengths are
averaged over a Maxwellian velocity distribution and results listed over a wide
range of temperatures, up to 10 K. Our data are compared with earlier
-matrix calculations and differences noted, up to a factor of two, for
several transitions. Although scope remains for improvement, the accuracy for
our results of collision strengths and effective collision strengths is
assessed to be about 20% for a majority of transitions.Comment: Text: 8 pages, Tables: 6, Figures: 8 Will appear in MNRAS (2014
Assessment of atomic data: problems and solutions
For the reliable analysis and modelling of astrophysical, laser-produced and
fusion plasmas, atomic data are required for a number of parameters, including
energy levels, radiative rates and electron impact excitation rates. Such data
are desired for a range of elements (H to W) and their many ions. However,
measurements of atomic data, mainly for radiative and excitation rates, are not
feasible for many species and therefore calculations are needed. For some ions
(such as of C, Fe and Kr) there are a variety of calculations available in the
literature, but often they significantly differ from one another. Therefore,
there is a great demand from the user community to have data `assessed' for
accuracy so that they can be confidently applied to the modelling of plasmas.
In this paper we highlight the difficulties in assessing atomic data and offer
some solutions for improving the accuracy of calculated results.Comment: 17 pages of Text only with 60 References - to be published in FS&T
(2013
Energy levels and radiative rates for transitions in Ti VI
We report on calculations of energy levels, radiative rates, oscillator
strengths, and line strengths for transitions among the lowest 253 levels of
the (1s2s2p) 3s3p, 3s3p, 3s3p3d, 3s3p3d,
3s3p, 3s3p4s, 3s3p4p and 3s3p4d
configurations of Ti VI. The general-purpose relativistic atomic structure
package ({\sc grasp}) and flexible atomic code ({\sc fac}) are adopted for the
calculations. Radiative rates, oscillator strengths and line strengths are
reported for all electric dipole (E1), magnetic dipole (M1), electric
quadrupole (E2) and magnetic quadrupole (M2) transitions among the 253 levels,
although calculations have been performed for a much larger number of levels.
Comparisons are made with existing available results and the accuracy of the
data is assessed. Additionally, lifetimes for all 253 levels are listed,
although comparisons with other theoretical results are limited to only 88
levels. Our energy levels are estimated to be accurate to better than 1%
(within 0.03 Ryd), whereas results for other parameters are probably accurate
to better than 20%. A reassessment of the energy level data on the NIST website
for Ti VI is suggested.Comment: 12p Text and 9 Tables will appear in Physica Scripta 88 (2013) xxxxx
Energy levels, radiative rates, and lifetimes for transitions in W XL
Energy levels and radiative rates are reported for transitions in Br-like W
XL, calculated with the general-purpose relativistic atomic structure package
({\sc grasp}). Configuration interaction (CI) has been included among 46
configurations (generating 4215 levels) over a wide energy range up to 213 Ryd.
However, for conciseness results are only listed for the lowest 360 levels
(with energies up to 43 Ryd), which mainly belong to the 4s4p,
4s4p4d, 4s4p4f, 4s4p, 4p4d, 4s4p4d,
4s4p4d, and 4s4p4d4f configurations, and provided for four
types of transitions, i.e. E1, E2, M1, and M2. Comparisons are made with
existing (but limited) results. However, to fully assess the accuracy of our
data, analogous calculations have been performed with the flexible atomic code
({\sc fac}), including even a larger CI than in {\sc grasp}. Our energy levels
are estimated to be accurate to better than 0.02 Ryd, whereas results for
radiative rates (and lifetimes) should be accurate to better than for a
majority of the strong transitions.Comment: 12p Text+2 Tables. The paper will appear this year in ADND
An Australian longitudinal pilot study examining health determinants of cardiac outcomes 12 months post percutaneous coronary intervention
Background
Percutaneous coronary intervention (PCI) is a very common revascularisation procedure for coronary artery disease (CAD). The purpose of this study was to evaluate cardiac outcomes, health related quality of life (HRQoL), resilience and adherence behaviours in patients who have undergone a PCI at two time points (6 and 12 months) following their procedure.
Methods
A longitudinal pilot study was conducted to observe the cardiac outcomes across a cohort of patients who had undergone a percutaneous coronary intervention (PCI). Participants who had undergone PCI 6 months prior were invited. Those participants who met the inclusion criteria and provided consent then completed a telephone survey (time point 1). These participants were then contacted 6 months later (i.e. 12 months post-intervention, time point 2) and the measures were repeated.
Results
All patients (n = 51) were recorded as being alive at time point 1. The multiple model indicated that controlling for other factors, gender was significantly associated with a linear combination of outcome measures (p = 0.004). The effect was moderate in magnitude (partial-η2 = 0.303), where males performed significantly better than females 6 months after the PCI procedure physically and with mood. Follow-up univariate ANOVAs indicated that gender differences were grounded in the scale measuring depression (PHQ9) (p = 0.005) and the physical component score of the short form measuring HRQoL (SF12-PCS) (p = 0.003). Thirteen patients were lost to follow-up between time points 1 and 2. One patient was confirmed to have passed away. The pattern of correlations between outcome measures at time point 2 revealed statistically significant negative correlation between the PHQ instrument and the resilience scale (CD-RISC) (r = -0.611; p < 0.001); and the physical component score of the SF-12 instrument (r = -0.437; p = 0.054).
Conclusions
Men were performing better than women in the 6 months post-PCI, particularly in the areas of mood (depression) and physical health. This pilot results indicate gender-sensitive practices are recommended particularly up to 6 months post-PCI. Any gender differences observed at 6 month appear to disappear at 12 months post-PCI. Further research into the management of mood particularly for women post-PCI is warranted. A more detailed inquiry related to access/attendance to secondary prevention is also warranted
Snippet based trajectory statistics histograms for assistive technologies
Due to increasing hospital costs and traveling time, more and more patients decide to use medical devices at home without traveling to the hospital. However, these devices are not always very straight-forward for usage, and the recent reports show that there are many injuries and even deaths caused by the wrong use of these devices. Since human supervision during every usage is impractical, there is a need for computer vision systems that would recognize actions and detect if the patient has done something wrong. In this paper, we propose to use Snippet Based Trajectory Statistics Histograms descriptor to recognize actions in two medical device usage problems; inhaler device usage and infusion pump usage. Snippet Based Trajectory Statistics Histograms encodes the motion and position statistics of densely extracted trajectories from a video. Our experiments show that by using Snippet Based Trajectory Statistics Histograms technique, we improve the overall performance for both tasks. Additionally, this method does not require heavy computation, and is suitable for real-time systems. © Springer International Publishing Switzerland 2015
Correlations of Behavioral Deficits with Brain Pathology Assessed through Longitudinal MRI and Histopathology in the R6/2 Mouse Model of HD
Huntington's disease (HD) is caused by the expansion of a CAG repeat in the huntingtin (HTT) gene. The R6/2 mouse model of HD expresses a mutant version of exon 1 HTT and develops motor and cognitive impairments, a widespread huntingtin (HTT) aggregate pathology and brain atrophy. Despite the vast number of studies that have been performed on this model, the association between the molecular and cellular neuropathology with brain atrophy, and with the development of behavioral phenotypes remains poorly understood. In an attempt to link these factors, we have performed longitudinal assessments of behavior (rotarod, open field, passive avoidance) and of regional brain abnormalities determined through magnetic resonance imaging (MRI) (whole brain, striatum, cortex, hippocampus, corpus callosum), as well as an end-stage histological assessment. Detailed correlative analyses of these three measures were then performed. We found a gender-dependent emergence of motor impairments that was associated with an age-related loss of regional brain volumes. MRI measurements further indicated that there was no striatal atrophy, but rather a lack of striatal growth beyond 8 weeks of age. T2 relaxivity further indicated tissue-level changes within brain regions. Despite these dramatic motor and neuroanatomical abnormalities, R6/2 mice did not exhibit neuronal loss in the striatum or motor cortex, although there was a significant increase in neuronal density due to tissue atrophy. The deposition of the mutant HTT (mHTT) protein, the hallmark of HD molecular pathology, was widely distributed throughout the brain. End-stage histopathological assessments were not found to be as robustly correlated with the longitudinal measures of brain atrophy or motor impairments. In conclusion, modeling pre-manifest and early progression of the disease in more slowly progressing animal models will be key to establishing which changes are causally related. © 2013 Rattray et al
New structural analogues of curcumin exhibit potent growth suppressive activity in human colorectal carcinoma cells
<p>Abstract</p> <p>Background</p> <p>Colorectal carcinoma is one of the major causes of morbidity and mortality in the Western World. Novel therapeutic approaches are needed for colorectal carcinoma. Curcumin, the active component and yellow pigment of turmeric, has been reported to have several anti-cancer activities including anti-proliferation, anti-invasion, and anti-angiogenesis. Clinical trials have suggested that curcumin may serve as a potential preventive or therapeutic agent for colorectal cancer.</p> <p>Methods</p> <p>We compared the inhibitory effects of curcumin and novel structural analogues, GO-Y030, FLLL-11, and FLLL-12, in three independent human colorectal cancer cell lines, SW480, HT-29, and HCT116. MTT cell viability assay was used to examine the cell viability/proliferation and western blots were used to determine the level of PARP cleavages. Half-Maximal inhibitory concentrations (IC<sub>50</sub>) were calculated using Sigma Plot 9.0 software.</p> <p>Results</p> <p>Curcumin inhibited cell viability in all three of the human colorectal cancer cell lines studied with IC<sub>50 </sub>values ranging between 10.26 μM and 13.31 μM. GO-Y030, FLLL-11, and FLLL-12 were more potent than curcumin in the inhibition of cell viability in these three human colorectal cancer cell lines with IC<sub>50 </sub>values ranging between 0.51 μM and 4.48 μM. In addition, FLLL-11 and FLLL-12 exhibit low toxicity to WI-38 normal human lung fibroblasts with an IC-50 value greater than 1,000 μM. GO-Y030, FLLL-11, and FLLL-12 are also more potent than curcumin in the induction of apoptosis, as evidenced by cleaved PARP and cleaved caspase-3 in all three human colorectal cancer cell lines studied.</p> <p>Conclusion</p> <p>The results indicate that the three curcumin analogues studied exhibit more potent inhibitory activity than curcumin in human colorectal cancer cells. Thus, they may have translational potential as chemopreventive or therapeutic agents for colorectal carcinoma.</p
Cardiosphere-derived cells suppress allogeneic lymphocytes by production of PGE2 acting via the EP4 receptor
derived cells (CDCs) are a cardiac progenitor cell population, which have been shown to possess cardiac regenerative properties and can improve heart function in a variety of cardiac diseases. Studies in large animal models have predominantly focussed on using autologous cells for safety, however allogeneic cell banks would allow for a practical, cost-effective and efficient use in a clinical setting. The aim of this work was to determine the immunomodulatory status of these cells using CDCs and lymphocytes from 5 dogs. CDCs expressed MHC I but not MHC II molecules and in mixed lymphocyte reactions demonstrated a lack of lymphocyte proliferation in response to MHC-mismatched CDCs. Furthermore, MHC-mismatched CDCs suppressed lymphocyte proliferation and activation in response to Concanavalin A. Transwell experiments demonstrated that this was predominantly due
to direct cell-cell contact in addition to soluble mediators whereby CDCs produced high levels of PGE2
under inflammatory conditions. This led to down-regulation of CD25 expression on lymphocytes via the
EP4 receptor. Blocking prostaglandin synthesis restored both, proliferation and activation (measured via CD25 expression) of stimulated lymphocytes. We demonstrated for the first time in a large animal model that CDCs inhibit proliferation in allo-reactive lymphocytes and have potent immunosuppressive activity mediated via PGE2
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