10 research outputs found
Analytic estimates and topological properties of the weak stability boundary
The weak stability boundary (WSB) is the transition region of the phase space where the change from gravitational escape to ballistic capture occurs. Studies on this complicated region of chaotic motion aim to investigate its unique, fuel saving properties to enlarge the frontiers of low energy transfers. This âfuzzy stabilityâ region is characterized by highly sensitive motion, and any analysis of it has been carried out almost exclusively using numerical methods. On the contrary this paper presents, for the planar circular restricted 3 body problem (PCR3BP), 1) an analytic definition of the WSB which is coherent with the known algorithmic definitions; 2) a precise description of the topology of the WSB; 3) analytic estimates on the âstable regionâ (nearby the smaller primary) whose boundary is, by definition, the WSB
Adipose tissue concentrations of non-persistent environmental phenols and local redox balance in adults from Southern Spain
The aim was to evaluate the associations of environmental phenol and paraben concentrations with the oxidative
microenvironment in adipose tissue. This study was conducted in a subsample (n=144) of the GraMo cohort
(Southern Spain). Concentrations of 9 phenols and 7 parabens, and levels of oxidative stress biomarkers were
quantified in adipose tissue. Associations were estimated using multivariable linear regression analyses adjusted
for potential confounders.
Benzophenone-3 (BP-3) concentration was borderline associated with enhanced glutathione peroxidase (GPx)
activity [exp(β)=1.20, p=0.060] and decreased levels of reduced glutathione (GSH) [exp(β)=0.55,
p=0.070]. Concentrations of bisphenol A (BPA) and methylparaben (MeP) were associated to lower glutathione
reductase (GRd) activity [exp(β)=0.83, exp(β)=0.72, respectively], and BPA was borderline associated
to increased levels of oxidized glutathione (GSSG) [exp(β)=1.73, p-value=0.062]. MeP was inversely
associated to both hemeoxygenase-1 (HO-1) and superoxide dismustase (SOD) activity, as well as to the levels of
thiobarbituric acid reactive substances (TBARS) [0.75 < exp(β) < 0.79].
Our results suggest that some specific non-persistent pollutants may be associated with a disruption of the
activity of relevant antioxidant enzymes, in addition to the depletion of the glutathione stock. They might act as
a tissue-specific source of free radicals, contributing to the oxidative microenvironment in the adipose tissue.This research was supported
in part by research grants from the European Union Commission
(H2020-EJP-HBM4EU and SOE1/P1/F0082), Biomedical Research
Networking Center-CIBER de EpidemiologĂa y Salud PĂşblica
(CIBERESP), from the Institute of Health Carlos III, supported by
European Regional Development Fund/FEDER (FIS-PI13/02406, FISPI14/
00067, FIS-PI16/01820, FIS-PI16/01812, FIS-PI16/01858 and
FIS-PI17/01743), and from the ConsejerĂa de Salud, Junta de AndalucĂa
(PS-0506-2016). Funding for the equipment used was provided by
Velux Fonden, Augustinus Fonden and Svend Andersen Fonden. The
authors thank Kirsten og Freddy Johansens Fond and the International
Centre for Research and Research Training in Endocrine Disruption of
Male Reproduction and Child Health (EDMaRC, Rigshospitalet,
Copenhagen University) for economic support. Dr. Juan Pedro Arrebola
is under contract within RamĂłn y Cajal Program (Ministerio de
EconomĂa, Industria y Competitividad de EspaĂąa, RYC-2016-20155)