The Aarhus red giants challenge Christensen-Dalsgaard, J.; Silva Aguirre, V.; Cassisi, S. ...
Astronomy and astrophysics (Berlin),
03/2020, Volume:
635
Journal Article
Peer reviewed
Open access
Contact.
The large quantity of high-quality asteroseismic data that have been obtained from space-based photometric missions and the accuracy of the resulting frequencies motivate a careful ...consideration of the accuracy of computed oscillation frequencies of stellar models, when applied as diagnostics of the model properties.
Aims.
Based on models of red-giant stars that have been independently calculated using different stellar evolution codes, we investigate the extent to which the differences in the model calculation affect the model oscillation frequencies and other asteroseismic diagnostics.
Methods.
For each of the models, which cover four different masses and different evolution stages on the red-giant branch, we computed full sets of low-degree oscillation frequencies using a single pulsation code and, from these frequencies, typical asteroseismic diagnostics. In addition, we carried out preliminary analyses to relate differences in the oscillation properties to the corresponding model differences.
Results.
In general, the differences in asteroseismic properties between the different models greatly exceed the observational precision of these properties. This is particularly true for the nonradial modes whose mixed acoustic and gravity-wave character makes them sensitive to the structure of the deep stellar interior and, hence, to details of their evolution. In some cases, identifying these differences led to improvements in the final models presented here and in Paper I; here we illustrate particular examples of this.
Conclusions.
Further improvements in stellar modelling are required in order fully to utilise the observational accuracy to probe intrinsic limitations in the modelling and improve our understanding of stellar internal physics. However, our analysis of the frequency differences and their relation to stellar internal properties provides a striking illustration of the potential, in particular, of the mixed modes of red-giant stars for the diagnostics of stellar interiors.
Purpose: The purpose of this study was to evaluate the effect of chitosan on lingual hemostasis in rabbits whose coagulation pathway had been impaired by administration of intravenous heparin.
...Materials and Methods: Bleeding times were measured for bilateral (15 mm × 2 mm) tongue incisions in 10 New Zealand white rabbits. Using a randomized, blinded experimental design, one incision in each animal was treated with chitosan, and the other was treated with the control vehicle without chitosan. Activated coagulation times and extraoral bleeding times were measured for each animal before, during, and after heparinization.
Results: Intravenous infusion of heparin more than tripled the mean activated coagulation time and increased mean systemic bleeding time by 40%. In this heparinized animal model, lingual incisions receiving the experimental substance showed a 43% improvement in bleeding time as compared with lingual incisions receiving the control solution (
P ≤.001). Chitosan treatment brought bleeding time of the lingual incision for heparinized animals within the normal range. Scanning electron microscopic evaluation of the incisions treated with chitosan showed an altered red blood cell morphology and an unusual affinity between erythrocytes.
Conclusions: Topical application of chitosan to lingual incisions effectively decreased intraoral bleeding time in a therapeutically anticoagulated (heparinized) rabbit model. Chitosan facilitated lingual hemostasis, possibly through interaction with erythrocytes, linking them together to establish a cellular clot or hemostatic plug.
Obesity-related decline in high-density lipoprotein (HDL) functions such as cholesterol efflux capacity (CEC) has supported the notion that this lipoprotein dysfunction may contribute for ...atherogenesis among obese patients. We investigated if potentially other HDL protective actions may be affected with weight gain and these changes may occur even before the obesity range in a cross-sectional analysis.
Lipid profile, body mass index (BMI), biochemical measurements, and carotid intima-media thickness (cIMT) were obtained in this cross-sectional study with 899 asymptomatic individuals. Lipoproteins were separated by ultracentrifugation and HDL physical-chemical characterization, CEC, antioxidant activity, anti-inflammatory activity, HDL-mediated platelet aggregation inhibition were measured in a randomly-selected subgroup (n = 101).
Individuals with increased HDL-C had an attenuated increase in cIMT with elevation of BMI (interaction effect β = −0.054; CI 95% −0.0815, −0.0301). CEC, HDL-C, HDL size and HDL-antioxidant activity were negatively associated with cIMT. BMI was inversely correlated with HDL-mediated inhibition of platelet aggregation (Spearman's rho −0.157, p < 0.03) and CEC (Spearman's rho −0.32, p < 0.001), but surprisingly it was directly correlated with the antioxidant activity (Spearman's rho 0.194, p = 0.052). Thus, even in non-obese, non-diabetic individuals, increased BMI is associated with a wide change in protective functions of HDL, reducing CEC and increasing antioxidant activity. In these subjects, decreased HDL concentration, size or function are related to increased atherosclerotic burden.
Our findings demonstrate that in non-obese, non-diabetic individuals, the increasing values of BMI are associated with impaired protective functions of HDL and concomitant increase in atherosclerotic burden.
•Multiple and complex relationship exists between HDL functions and excess weight.•BMI is inversely associated with HDL-mediated inhibition of platelet aggregation and CEC, but directly associated with the antioxidant activity.•Decreased HDL concentration, size or function are related to increased atherosclerotic burden and increased BMI.
Background
Various imaging techniques are used for management of patients with multiple myeloma (MM) after Autologous Stem Cell Transplantation (ASCT). Between them, PET-CT is a whole-body, ...high-sensitive imaging tool used to discriminate bone involvement. About the prognostic role of PET-CT, the NCCN guidelines state that “PET-CT results after induction therapy and stem cell transplant help in predicting prognosis of patients with symptomatic MM”. Several previous studies demonstrated that the presence of at least 3 focal lesions with SUV>4.2 and extra-medullary disease was associated to shorter PFS and OS Zamagni E, 2011. With these premises, we decided to retrospectively assess if PET-CT precociously performed after ASCT (at 3-6 months) would be able to predict the quality of response or survival in our series of autotransplanted MM patients.
Methods
45 patients underwent to PET-CT after ASCT: two third of them received as induction the combination of bortezomib, thalidomide, and dexamethasone (VTD); another quarter received bortezomib, anthracycline, and dexamethasone (VAD); the remaining subjects were treated with bortezomib or thalidomide and dexamethasone (VD, TD).
Results
The 67% of patients receiving VTD as induction achieved a response, with 69% of CR+VGPR versus the only 7% of optimal responses offered by the VAD regimen. At the end of the high-dose procedure, overall 62% of our patients were in CR o VGPR. The median OS was 58 months, and at 40 months the 45% of our patients was still progression-free. In order to avoid positive and negative falses, we calculated the specificity and the sensitivity of PET-CT: in our hands, PET-CT sensitivity resulted 60.7% and specificity 29.4%. For further details, see Table1.The PET-CT positivity did not significantly correlate with the clinical response assessed at the same time-points: indeed, in the subgroup of PET-CT-positive cases, the 26.7% showed a poor response, as expected. Nevertheless, unexpectedly, the 37.8% of positive cases achieved at least a VGPR. On the other hand, the 24.4% of cases with negative PET-CT were in good response, but, conversely, 11.1% of these PET-negative patients were in poor response (p=ns). Overall, the median OS was 17 months in PET-CT-positive patients versus not reached at 40 months in the negative subgroup; nevertheless, this difference was not statistically significant (p=0.29). Finally, we assessed if PET-CT status after ASCT could predict the OS length: in this setting, the median OS was 23 months for PET-CT-positive patients versus not reached at 40 months in the negative subgroup; even in this case, this difference was not statistically significant (p=0.28). The same analysis was performed in terms of PFS: overall, the median PFS was 18 months in PET-CT-positive patients versus 37 months in the negative subgroup; (p=0.55). Finally, we assessed if PET-CT status during follow-up could predict the PFS length: the median PFS of the entire series was 32 months for PET-CT-positive patients versus 60 months in the negative subgroup; once more, this difference was not statistically significant (p=0.15).
Conclusions
In conclusion, the status of PET-CT precociously performed after ASCT was not able to discriminate quality of response or survivals in our patients. This result does not confirm already published data; we argue that this discrepancy could depend on the adoption in our series of the newer and more effective regimens in respect of the VAD, previously adopted in the studies where a significant prognostic impact of PET-CT was demonstrated. Finally, another relevant aspect of our study is that it represents the output of a real-life experience.
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MicroRNAs are key regulators of many biological processes, including cell differentiation. These small RNAs exert their function assembled in the RNA-induced silencing complexes (RISCs), where ...members of Argonaute (Ago) family of proteins provide a unique platform for target recognition and gene silencing. Here, by using myeloid cell lines and primary blasts, we show that Ago2 has a key role in human monocytic cell fate determination and in LPS-induced inflammatory response of 1,25-dihydroxyvitamin D3 (D3)-treated myeloid cells. The silencing of Ago2 impairs the D3-dependent miR-17-5p/20a/106a, miR-125b and miR-155 downregulation, the accumulation of their translational targets AML1, VDR and C/EBPβ and monocytic cell differentiation. Moreover, we show that Ago2 is recruited on miR-155 host gene promoter and on the upstream region of an overlapping antisense lncRNA, determining their epigenetic silencing, and miR-155 downregulation. These findings highlight Ago2 as a new factor in myeloid cell fate determination in acute myeloid leukemia cells.
The MDR1 gene encodes the P-glycoprotein, an efflux transporter with broad substrate specificity. P-glycoprotein has raised great interest in pharmacogenetics because it transports a variety of ...structurally divergent drugs, including lipid-lowering drugs. The synonymous single-nucleotide polymorphism C3435T and the nonsynonymous single-nucleotide polymorphism G2677T/A in MDR1 have been indicated as potential determinants of variability in drug disposition and efficacy. In order to evaluate the effect of G2677T/A and C3435T MDR1 polymorphisms on serum levels of lipids before and after atorvastatin administration, 69 unrelated hypercholesterolemic individuals from São Paulo city, Brazil, were selected and treated with 10 mg atorvastatin orally once daily for four weeks. MDR1 polymorphisms were analyzed by PCR-RFLP. C3435T and G2677T polymorphisms were found to be linked. The allelic frequencies for C3435T polymorphism were 0.536 and 0.464 for the 3435C and 3435T alleles, respectively, while for G2677T/A polymorphism allele frequencies were 0.580 for the 2677G allele, 0.384 for the 2677T allele and 0.036 for the 2677A allele. There was no significant relation between atorvastatin response and MDR1 polymorphisms (repeated measures ANOVA; P > 0.05). However, haplotype analysis revealed an association between T/T carriers and higher basal serum total (TC) and LDL cholesterol levels (TC: 303 +/- 56, LDL-C: 216 +/- 57 mg/dl, respectively) compared with non-T/T carriers (TC: 278 +/- 28, LDL-C: 189 +/- 24 mg/dl; repeated measures ANOVA/Tukey test; P < 0.05). These data indicate that MDR1 polymorphism may have an important contribution to the control of basal serum cholesterol levels in Brazilian hypercholesterolemic individuals of European descent.
Working in the context of a proposal for collisional dark matter, we derive bounds on the Higgs boson coupling g′ to a stable light scalar particle, which we refer to as phion (φ), required to solve ...problems with small scale structure formation which arise in collisionless dark matter models. We discuss the behaviour of the phion in the early universe for different ranges of its mass. We find that a phion in the mass range of 100 MeV is excluded and that a phion in the mass range of 1 GeV requires a large coupling constant, g′≳2, and mh≲130 GeV in order to avoid overabundance, in which case the invisible decay mode of the Higgs boson would be dominant.
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