2,973 research outputs found
Self-pulsing dynamics of ultrasound in a magnetoacoustic resonator
A theoretical model of parametric magnetostrictive generator of ultrasound is
considered, taking into account magnetic and magnetoacoustic nonlinearities.
The stability and temporal dynamics of the system is analized with standard
techniques revealing that, for a given set of parameters, the model presents a
homoclinic or saddle--loop bifurcation, which predicts that the ultrasound is
emitted in the form of pulses or spikes with arbitrarily low frequency.Comment: 5 pages, 5 figure
Excitability in a nonlinear magnetoacoustic resonator
We report a nonlinear acoustic system displaying excitability. The considered
system is a magnetostrictive material where acoustic waves are parametrically
generated. For a set of parameters, the system presents homoclinic and
heteroclinic dynamics, whose boundaries define a excitability domain. The
excitable behaviour is characterized by analyzing the response of the system to
different external stimuli. Single spiking and bursting regimes have been
identified.Comment: 4 pages, 5 figure
Selective Inhibition of Vascular Endothelial Growth Factor–mediated Angiogenesis by Cyclosporin A: Roles of the Nuclear Factor of Activated T Cells and Cyclooxygenase 2
Cyclosporin A (CsA) is an immunosuppressive drug that inhibits the activity of transcription factors of the nuclear factor of activated T cells (NFAT) family, interfering with the induction of cytokines and other inducible genes required for the immune response. Here we show that CsA inhibits migration of primary endothelial cells and angiogenesis induced by vascular endothelial growth factor (VEGF); this effect appears to be mediated through the inhibition of cyclooxygenase (Cox)-2, the transcription of which is activated by VEGF in primary endothelial cells. Consistent with this, we show that the induction of Cox-2 gene expression by VEGF requires NFAT activation. Most important, the CsA-mediated inhibition of angiogenesis both in vitro and in vivo was comparable to the Cox-2 inhibitor NS-398, and reversed by prostaglandin E2. Furthermore, the in vivo corneal angiogenesis induced by VEGF, but not by basic fibroblast growth factor, was selectively inhibited in mice treated with CsA systemically. These findings involve NFAT in the regulation of Cox-2 in endothelial cells, point to a role for this transcription factor in angiogenesis, and may provide a novel mechanism underlying the beneficial effects of CsA in angiogenesis-related diseases such as rheumatoid arthritis and psoriasis.This work was supported by grant PM99-0116 from Ministerio de Educación y Cultura (MEC-DGES) of Spain (to J.M. Redondo) and grants FEDER 1FD97-0514-CO2-01 and FEDER FD97-0275 from MEC-DGES and the European Community to J.M. Redondo and M. Fresno, respectively. G.L. Hernández was supported by grants from Consejo Superior de Investigaciones Científicas y Tecnológicas (CONICET) of Argentina and Comunidad Autónoma de Madrid grant 8.3/0024/2000, and M. Fresno by grant PM97-0130, O. Volpert by American Heart Association grant AHA SDG 0030023N, and S. Martínez-Martínez by grant 8.3/19/1998 from the Comunidad Autónoma de Madrid. The Centro de Biología Molecular "Severo Ochoa" is supported by a grant from the Fundación Ramón ArecesPeer reviewe
Selective Inhibition of Vascular Endothelial Growth Factor–Mediated Angiogenesis by Cyclosporin a: Roles of the Nuclear Factor of Activated T Cells and Cyclooxygenase 2
Cyclosporin A (CsA) is an immunosuppressive drug that inhibits the activity of transcription factors of the nuclear factor of activated T cells (NFAT) family, interfering with the induction of cytokines and other inducible genes required for the immune response. Here we show that CsA inhibits migration of primary endothelial cells and angiogenesis induced by vascular endothelial growth factor (VEGF); this effect appears to be mediated through the inhibition of cyclooxygenase (Cox)-2, the transcription of which is activated by VEGF in primary endothelial cells. Consistent with this, we show that the induction of Cox-2 gene expression by VEGF requires NFAT activation. Most important, the CsA-mediated inhibition of angiogenesis both in vitro and in vivo was comparable to the Cox-2 inhibitor NS-398, and reversed by prostaglandin E2. Furthermore, the in vivo corneal angiogenesis induced by VEGF, but not by basic fibroblast growth factor, was selectively inhibited in mice treated with CsA systemically. These findings involve NFAT in the regulation of Cox-2 in endothelial cells, point to a role for this transcription factor in angiogenesis, and may provide a novel mechanism underlying the beneficial effects of CsA in angiogenesis-related diseases such as rheumatoid arthritis and psoriasis
Bone health in children and youth with Cystic Fibrosis: a systematic review and meta-analysis of matched cohort studies
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordObjective
To assess the evidence regarding the differences in areal bone mineral density (aBMD) between children and adolescents with cystic fibrosis (CF) compared with their healthy peers, based on data from longitudinal studies.
Study design
We searched MEDLINE, SPORTDiscus, the Cochrane Library, PEDro (Physiotherapy Evidence Database), and Embase databases. Observational studies addressing the change of aBMD in children with CF and healthy children and adolescents were eligible. The DerSimonian and Laird method was used to compute pooled estimates of effect sizes (ES) and 95% CIs for the change of whole body (WB), lumbar spine (LS), and femoral neck (FN) aBMD.
Results
Six studies with participants with CF and 26 studies with healthy participants were included in the systematic review and meta-analysis. For the analysis in children with CF, the pooled ES for the change of WB aBMD was 0.29 (95% CI –0.15 to 0.74), for the change of LS aBMD was 0.13 (95% CI –0.16 to 0.41), and for the change of FN aBMD was 0.09 (95% CI –0.39 to 0.57). For the analysis in healthy children, the pooled ES for the change of WB aBMD was 0.37 (95% CI 0.26-0.49), for the change of LS aBMD was 0.13 (95% CI –0.16 to 0.41), and for the change of FN aBMD was 0.52 (95% CI 0.19-0.85).
Conclusions
aBMD development might not differ between children and adolescents with CF receiving medical care compared with their healthy peers. Further longitudinal studies in a CF population during growth and development are required to confirm our findings
Agreement between dual-energy X-ray absorptiometry and quantitative ultrasound to evaluate bone health in adolescents: The PRO-BONE study
Purpose: The present study aims to investigate the association between dual-energy X-ray absorptiometry (DXA) and quantitative ultrasound (QUS) parameters and the intermethods agreement in active males.
Methods: In this cross-sectional study, bone health (by DXA and calcaneal QUS), physical activity (by accelerometers), and anthropometrics measurements were assessed in 117 active adolescents (12–14 y old). Bivariate correlation coefficients were calculated to assess the relationships between DXA standard regions of interest and QUS parameters. Intraclass correlation coefficients and Bland–Altman plots were used to assess the level of agreement between bone mineral content regions derived from DXA and stiffness index. The measurements were z score transformed for comparison.
Results: Most QUS parameters were positive and significantly correlated with DXA outcomes (stiffness index: r = .43–.52; broadband ultrasound attenuation: r = .50–.58; speed of sound: r = .25–.27) with the hip showing the highest correlations. Moreover, the present study found fair to good intraclass correlation coefficients of agreement (.60–.68) between DXA and QUS to assess bone health. The Bland–Altman analysis showed a limited percentage of outliers (3.2%–8.6%).
Conclusion: QUS device could represent an acceptable alternative method to assess bone health in active adolescent males
Prevalence of Overweight and Obesity among European Preschool Children: A Systematic Review and Meta-Regression by Food Group Consumption
The aim of this review was to estimate the prevalence of overweight and obesity among European children aged 2–7 years from 2006 to 2016 and to analyze these estimations by gender, country, and food group consumption. We searched CINAHL, EMBASE, MEDLINE, and Web of Science databases from their inception until 27 February 2019 including cross-sectional studies and baseline measurements of cohort studies with overweight and obesity defined according to the International Obesity Task Force criteria. Both the inverse-variance fixed-effects method and the DerSimonian and Laird random effects method were used to determinate pooled prevalence estimates and their respective 95% confidence intervals (CIs). A total of 32 studies (n = 197,755 children) with data from 27 European countries were included. Overall, the pooled prevalence estimates of overweight/obesity in European children (aged 2–7 years) during the period 2006–2016 was 17.9% (95% CI: 15.8–20.0), and the pooled prevalence estimate of obesity was 5.3% (95% CI: 4.5–6.1). Southern European countries showed the highest prevalence of excess weight. Additional measures to address the obesity epidemic in early life should be established, especially in European countries where the prevalence of excess weight is very high.M.G.-M. is supported by grants from the Ministerio de Educación, Cultura y Deporte, (FPU15/03847). A.S.-C. is supported by a grant from Spanish Ministry of Economy, Industry, and Competitiveness (Fi 17/332)
Handgrip and knee extension strength as predictors of cancer mortality: A systematic review and metaâ analysis
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145272/1/sms13206.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145272/2/sms13206_am.pd
Glycated haemoglobin A1c as a risk factor of cardiovascular outcomes and all-cause mortality in diabetic and non-diabetic populations: a systematic review and meta-analysis
Objective: To examine the relationship between glycated haemoglobin A1c (HbA1c) levels and the risk of cardiovascular outcomes and all-cause mortality based on data from observational studies and to determine the optimal levels of HbA1c for preventing cardiovascular events and/or mortality in diabetic and non-diabetic populations.
Review methods: We systematically searched Medline, Embase, the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews and Web of Science databases, from inception to July 2016, for observational studies addressing the association of HbA1c levels with mortality and cardiovascular outcomes. Random effects models were used to compute pooled estimates of HR and respective 95% CI for all-cause mortality, cardiovascular mortality and risk of cardiovascular events, separately for people with and without diabetes.
Results: Seventy-four published studies were included in the systematic review, but only 46 studies could be incorporated in the meta-analysis. In both diabetic and non-diabetic populations, there was an increase in the risk of all-cause mortality when HbA1c levels were over 8.0% and 6.0%, respectively. The highest all-cause mortality in people with diabetes was HbA1c above 9.0% (HR=1.69; 95% CI 1.09 to 2.66) and in those without diabetes was HbA1c above 6.0% (HR=1.74; 95% CI 1.38 to 2.20). However, both diabetic and non-diabetic populations with lower HbA1c levels (below 6.0% HR=1.57; 95% CI 1.14 to 2.17 and below 5.0% HR=1.19; 95% CI 1.04 to 1.36, respectively) had higher all-cause mortality. Similar pooled estimates were found when cardiovascular mortality was the outcome variable.
Conclusion: HbA1c is a reliable risk factor of all-cause and cardiovascular mortality in both diabetics and non-diabetics. Our findings establish optimal HbA1c levels, for the lowest all-cause and cardiovascular mortality, ranging from 6.0% to 8.0% in people with diabetes and from 5.0% to 6.0% in those without diabetes.ICR is supported by a grant from the Universidad de Castilla-La Mancha (FPU13/01582). CAB is supported by a grant from the Spanish Ministry of Ministry of Education, Culture and Sport (FPU13/03137). BP is supported by a grant from the Portuguese Foundation for Science and Technology (SFRH/BPD/108751/2015)
Incidents control in radiotherapy oncology
Primer pla de l'escut del monarca del s. XVI,
conservat i ubicat a la porta de la UB. Mesura
1,60 x 2,20 metre si és de pedra sorrenca
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