110 research outputs found
Angular correlation measurements in O15
An accurate measurement of the energy of a gamma transition from the 7.56-Mev level in O15 discloses that the transition takes place to the 5.19-Mev level in O15 rather than to the 5.25-Mev level. Another transition takes place through the 6.15-Mev level. The third known transition occurs through the 6.79-Mev level rather than through the 6.86-Mev level. The angular correlations of cascades from the 7.56-Mev level through the levels at 6.79 Mev, 6.15 Mev, and 5.19 Mev are measured. These results, combined with previous results on these levels, are consistent only with JĎ€=3/2+ and 3/2-, respectively, for the 6.79-Mev and 6.15-Mev levels. For the 5.19-Mev level, the present results indicate J=1/2, but are consistent also with J=3/2, if a suitable mixing ratio of E2 to M1 radiation is chosen. The preferred assignments are all consistent with the shell-model predictions and with comparisons with the N15 level scheme. It is noted that the doublets near 5.2 Mev in O15 and N15 are reversed in order
Optical absorption spectra and monomer interaction in polymers. Investigation of exciton coupling in DNA hairpins
We investigate the effect of exciton coupling on the optical absorption
spectrum of polymer molecules under conditions of strong inhomogeneous
broadening. We demonstrate that the dependence of the maximum in the rescaled
absorption spectrum on the number of monomers is determined by the average
monomer excitation energies and their resonant coupling and insensitive to the
inhomogeneous broadening. Thus the absorption spectrum can be used to determine
optical interactions between monomers. The results are applied to the
absorption spectra of poly-A poly-T DNA hairpins and used to interpret the
dependence of the absorption spectrum on the number of monomers. We also
discuss exciton localization in these hairpins.Comment: Submitted to Journal of Chemical Physic
Revision of the 15N(p,{\gamma})16O reaction rate and oxygen abundance in H-burning zones
The NO cycle takes place in the deepest layer of a H-burning core or shell,
when the temperature exceeds T {\simeq} 30 {\cdot} 106 K. The O depletion
observed in some globular cluster giant stars, always associated with a Na
enhancement, may be due to either a deep mixing during the RGB (red giant
branch) phase of the star or to the pollution of the primordial gas by an early
population of massive AGB (asymptotic giant branch) stars, whose chemical
composition was modified by the hot bottom burning. In both cases, the NO cycle
is responsible for the O depletion. The activation of this cycle depends on the
rate of the 15N(p,{\gamma})16O reaction. A precise evaluation of this reaction
rate at temperatures as low as experienced in H-burning zones in stellar
interiors is mandatory to understand the observed O abundances. We present a
new measurement of the 15N(p,{\gamma})16O reaction performed at LUNA covering
for the first time the center of mass energy range 70-370 keV, which
corresponds to stellar temperatures between 65 {\cdot} 106 K and 780 {\cdot}106
K. This range includes the 15N(p,{\gamma})16O Gamow-peak energy of explosive
H-burning taking place in the external layer of a nova and the one of the hot
bottom burning (HBB) nucleosynthesis occurring in massive AGB stars. With the
present data, we are also able to confirm the result of the previous R-matrix
extrapolation. In particular, in the temperature range of astrophysical
interest, the new rate is about a factor of 2 smaller than reported in the
widely adopted compilation of reaction rates (NACRE or CF88) and the
uncertainty is now reduced down to the 10% level.Comment: 6 pages, 5 figure
Astrophysical S-factor for the radiative capture reaction 13C(p,g)14N
The phase shift analysis, done on the basis of the known measurements of the
differential cross-sections of the p13C elastic scattering at the energy range
250-750 keV, shows that it is enough to take into account only 3S1 wave in the
considered energy region. The potential for the triplet 3S1 state in p13C
system at the resonance energy 0.55 MeV corresponding to quantum numbers JpT =
1-1 as well as the potential for the 3P1 bound state of 14N were constructed on
the basis of the obtained scattering phase shifts. The possibility to describe
the experimental data of the astrophysical S-factor of the p13C radiative
capture at the energies 0.03-0.8 MeV was considered within the potential
cluster model with the forbidden states. It was shown that we properly succeed
in explanation of the energy behavior of the astrophysical S-factor for the
p13C radiative capture at the resonance energy range 0.55 MeV (laboratory
system).Comment: 8 p., 2 fi
Australian clinical practice guidelines for the diagnosis and management of Barrett's esophagus and early esophageal adenocarcinoma
Author version made available following 12 month embargo from date of publication according to publisher copyright policy.Barrett's esophagus (BE), a common condition, is the only known precursor to esophageal adenocarcinoma (EAC). There is uncertainty about the best way to manage BE as most people with BE never develop EAC and most patients diagnosed with EAC have no preceding diagnosis of BE. Moreover, there have been recent advances in knowledge and practice about the management of BE and early EAC. To aid clinical decision making in this rapidly moving field, Cancer Council Australia convened an expert working party to identify pertinent clinical questions. The questions covered a wide range of topics including endoscopic and histological definitions of BE and early EAC; prevalence, incidence, natural history, and risk factors for BE; and methods for managing BE and early EAC. The latter considered modification of lifestyle factors; screening and surveillance strategies; and medical, endoscopic, and surgical interventions. To answer each question, the working party systematically reviewed the literature and developed a set of recommendations through consensus. Evidence underpinning each recommendation was rated according to quality and applicability
Hepatitis C Virus Induces the Cannabinoid Receptor 1
BACKGROUND: Activation of hepatic CB(1) receptors (CB(1)) is associated with steatosis and fibrosis in experimental forms of liver disease. However, CB(1) expression has not been assessed in patients with chronic hepatitis C (CHC), a disease associated with insulin resistance, steatosis and metabolic disturbance. We aimed to determine the importance and explore the associations of CB(1) expression in CHC. METHODS: CB(1) receptor mRNA was measured by real time quantitative PCR on extracted liver tissue from 88 patients with CHC (genotypes 1 and 3), 12 controls and 10 patients with chronic hepatitis B (CHB). The Huh7/JFH1 Hepatitis C virus (HCV) cell culture model was used to validate results. PRINCIPAL FINDINGS: CB(1) was expressed in all patients with CHC and levels were 6-fold higher than in controls (P<0.001). CB(1) expression increased with fibrosis stage, with cirrhotics having up to a 2 fold up-regulation compared to those with low fibrosis stage (p<0.05). Even in mild CHC with no steatosis (F0-1), CB(1) levels remained substantially greater than in controls (p<0.001) and in those with mild CHB (F0-1; p<0.001). Huh7 cells infected with JFH-1 HCV showed an 8-fold upregulation of CB(1), and CB(1) expression directly correlated with the percentage of cells infected over time, suggesting that CB(1) is an HCV inducible gene. While HCV structural proteins appear essential for CB(1) induction, there was no core genotype specific difference in CB(1) expression. CB(1) significantly increased with steatosis grade, primarily driven by patients with genotype 3 CHC. In genotype 3 patients, CB(1) correlated with SREBP-1c and its downstream target FASN (SREBP-1c; R=0.37, FASN; R=0.39, p<0.05 for both). CONCLUSIONS/SIGNIFICANCE: CB(1) is up-regulated in CHC and is associated with increased steatosis in genotype 3. It is induced by the hepatitis C virus
Synchronous appendiceal and intramucosal gastric signet ring cell carcinomas in an individual with CDH1-associated hereditary diffuse gastric carcinoma: a case report of a novel association and review of the literature
NUDT2 Disruption Elevates Diadenosine Tetraphosphate (Ap4A) and Down-Regulates Immune Response and Cancer Promotion Genes.
Regulation of gene expression is one of several roles proposed for the stress-induced nucleotide diadenosine tetraphosphate (Ap4A). We have examined this directly by a comparative RNA-Seq analysis of KBM-7 chronic myelogenous leukemia cells and KBM-7 cells in which the NUDT2 Ap4A hydrolase gene had been disrupted (NuKO cells), causing a 175-fold increase in intracellular Ap4A. 6,288 differentially expressed genes were identified with P < 0.05. Of these, 980 were up-regulated and 705 down-regulated in NuKO cells with a fold-change ≥ 2. Ingenuity® Pathway Analysis (IPA®) was used to assign these genes to known canonical pathways and functional networks. Pathways associated with interferon responses, pattern recognition receptors and inflammation scored highly in the down-regulated set of genes while functions associated with MHC class II antigens were prominent among the up-regulated genes, which otherwise showed little organization into major functional gene sets. Tryptophan catabolism was also strongly down-regulated as were numerous genes known to be involved in tumor promotion in other systems, with roles in the epithelial-mesenchymal transition, proliferation, invasion and metastasis. Conversely, some pro-apoptotic genes were up-regulated. Major upstream factors predicted by IPA® for gene down-regulation included NFκB, STAT1/2, IRF3/4 and SP1 but no major factors controlling gene up-regulation were identified. Potential mechanisms for gene regulation mediated by Ap4A and/or NUDT2 disruption include binding of Ap4A to the HINT1 co-repressor, autocrine activation of purinoceptors by Ap4A, chromatin remodeling, effects of NUDT2 loss on transcript stability, and inhibition of ATP-dependent regulatory factors such as protein kinases by Ap4A. Existing evidence favors the last of these as the most probable mechanism. Regardless, our results suggest that the NUDT2 protein could be a novel cancer chemotherapeutic target, with its inhibition potentially exerting strong anti-tumor effects via multiple pathways involving metastasis, invasion, immunosuppression and apoptosis
Recommendations for effective documentation in regional anesthesia: an expert panel Delphi consensus project
Background and objectives: Documentation is important for quality improvement, education, and research. There is currently a lack of recommendations regarding key aspects of documentation in regional anesthesia. The aim of this study was to establish recommendations for documentation in regional anesthesia.
Methods: Following the formation of the executive committee and a directed literature review, a long list of potential documentation components was created. A modified Delphi process was then employed to achieve consensus amongst a group of international experts in regional anesthesia. This consisted of 2 rounds of anonymous electronic voting and a final virtual round table discussion with live polling on items not yet excluded or accepted from previous rounds. Progression or exclusion of potential components through the rounds was based on the achievement of strong consensus. Strong consensus was defined as ≥75% agreement and weak consensus as 50%-74% agreement.
Results: Seventy-seven collaborators participated in both rounds 1 and 2, while 50 collaborators took part in round 3. In total, experts voted on 83 items and achieved a strong consensus on 51 items, weak consensus on 3 and rejected 29.
Conclusion: By means of a modified Delphi process, we have established expert consensus on documentation in regional anesthesia
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