Resonance energy transfer in self-organized organic/inorganic dendrite structures

Hybrid materials formed by semiconductor quantum dots and J-aggregates of cyanine dyes provide a unique combination of enhanced absorption in inorganic constituents with large oscillator strength and extremely narrow exciton bands of the organic component. The optical properties of dendrite structures with fractal dimension 1.7–1.8, formed from J-aggregates integrated with CdTe quantum dots (QDs), have been investigated by photoluminescence spectroscopy and fluorescence lifetime imaging microscopy. Our results demonstrate that (i)J-aggregates are coupled to QDs by F¨orster-type resonant energy transfer and (ii) there are energy fluxes from the periphery to the centre of the structure, where the QD density is higher than in the periphery of the dendrite. Such an anisotropic energy transport can be only observed when dendrites are formed from QDs integrated with J-aggregates. These QD/ J-aggregate hybrid systems can have applications in light harvesting systems and optical sensors with extended absorption spectra.Fundação para a Ciência e a Tecnologia (FCT

Vibrational spectra of C60C8H8 and C70C8H8 in the rotor-stator and polymer phases

C60-C8H8 and C70-C8H8 are prototypes of rotor-stator cocrystals. We present infrared and Raman spectra of these materials and show how the rotor-stator nature is reflected in their vibrational properties. We measured the vibrational spectra of the polymer phases poly(C60C8H8) and poly(C70C8H8) resulting from a solid state reaction occurring on heating. Based on the spectra we propose a connection pattern for the fullerene in poly(C60C8H8), where the symmetry of the C60 is D2h. On illuminating the C60-C8H8 cocrystal with green or blue light a photochemical reaction was observed leading to a similar product to that of the thermal polymerization.Comment: 26 pages, 8 figures, to appear in Journal of Physical Chemistry B 2nd version: minor changes in wording, accepted version by journa

Prognostic value of cardiac magnetic resonance early after ST-segment elevation myocardial infarction in older patients

[EN] Background older patients with ST-segment elevation myocardial infarction (STEMI) represent a very high-risk population. Data on the prognostic value of cardiac magnetic resonance (CMR) in this scenario are scarce. Methods the registry comprised 247 STEMI patients over 70 years of age treated with percutaneous intervention and included in a multicenter registry. Baseline characteristics, echocardiographic parameters and CMR-derived left ventricular ejection fraction (LVEF, %), infarct size (% of left ventricular mass) and microvascular obstruction (MVO, number of segments) were prospectively collected. The additional prognostic power of CMR was assessed using adjusted C-statistic, net reclassification index (NRI) and integrated discrimination improvement index (IDI). Results during a 4.8-year mean follow-up, the number of first major adverse cardiac events (MACE) was 66 (26.7%): 27 all-cause deaths and 39 re-admissions for acute heart failure. Predictors of MACE were GRACE score (HR 1.03 [1.02-1.04], P 155, LVEF = 2 segments. A simple score (0, 1, 2, 3) based on the number of altered factors accurately predicted the MACE per 100 person-years: 0.78, 5.53, 11.51 and 78.79, respectively (P < 0.001). Conclusions CMR data contribute valuable prognostic information in older patients submitted to undergo CMR soon after STEMI. The Older-STEMI-CMR score should be externally validated.This work was supported by Instituto de Salud Carlos III and Fondos Europeos de Desarrollo Regional FEDER (grant numbers PI20/00637, PI15/00531, and CIBERCV16/11/00486,CIBERCV16/11/00420, CIBERCV16/11/00479), apostgraduate contract FI18/00320 to C.R.-N., CM21/00175 to V.M.-G. and JR21/00041 to C.B., Fundacio La MaratoTV3 (grant 20153030-31-32), La Caixa Banking Foundation (HR17-00527), by Conselleria de Educacion-Generalitat Valenciana (PROMETEO/2021/008) and by Sociedad Espanola de Cardiologia (grant SEC/FEC-INV-CLI 21/024). J.G. acknowledges financial support from the Agencia Estatal de Investigacion (grant FJC2020-043981-I/AEI/10.13039/501100011033). D.M. acknowledges financial support from the Conselleria d'Educacio,Investigacio, Cultura i Esport, Generalitat Valenciana (grants AEST/2019/037, AEST/2020/029).Gabaldón-Pérez A; Marcos-Garcés, V.; Gavara-Doñate, J.; López-Lereu, MP.; Monmeneu, JV.; Pérez, N.; Ríos-Navarro, C.... (2022). Prognostic value of cardiac magnetic resonance early after ST-segment elevation myocardial infarction in older patients. Age and Ageing. 51(11):1-11. https://doi.org/10.1093/ageing/afac248111511

The Cauchy problem of f(R) gravity

The initial value problem of metric and Palatini f(R)gravity is studied by using the dynamical equivalence between these theories and Brans-Dicke gravity. The Cauchy problem is well-formulated for metric f(R)gravity in the presence of matter and well-posed in vacuo. For Palatini f(R)gravity, instead, the Cauchy problem is not well-formulated.Comment: 16 latex pages, to appear in Class. Quantum Grav; typographical errors corrected, new references adde

Search for subsolar-mass black hole binaries in the second part of Advanced LIGO’s and Advanced Virgo’s third observing run

We describe a search for gravitational waves from compact binaries with at least one component with mass 0.2 M⊙–1.0 M⊙ and mass ratio q ≥ 0.1 in Advanced LIGO and Advanced Virgo data collected between 1 November 2019, 15:00 UTC and 27 March 2020, 17:00 UTC. No signals were detected. The most significant candidate has a false alarm rate of 0.2yr−1 ⁠. We estimate the sensitivity of our search over the entirety of Advanced LIGO’s and Advanced Virgo’s third observing run, and present the most stringent limits to date on the merger rate of binary black holes with at least one subsolar-mass component. We use the upper limits to constrain two fiducial scenarios that could produce subsolar-mass black holes: primordial black holes (PBH) and a model of dissipative dark matter. The PBH model uses recent prescriptions for the merger rate of PBH binaries that include a rate suppression factor to effectively account for PBH early binary disruptions. If the PBHs are monochromatically distributed, we can exclude a dark matter fraction in PBHs fPBH ≳ 0.6 (at 90% confidence) in the probed subsolar-mass range. However, if we allow for broad PBH mass distributions we are unable to rule out fPBH = 1. For the dissipative model, where the dark matter has chemistry that allows a small fraction to cool and collapse into black holes, we find an upper bound fDBH &lt; 10−5 on the fraction of atomic dark matter collapsed into black holes

Brane effective actions, kappa-symmetry and applications

This is a review on brane effective actions, their symmetries and some of their applications. Its first part covers the Green–Schwarz formulation of single M- and D-brane effective actions focusing on kinematical aspects: the identification of their degrees of freedom, the importance of world volume diffeomorphisms and kappa symmetry to achieve manifest spacetime covariance and supersymmetry, and the explicit construction of such actions in arbitrary on-shell supergravity backgrounds. Its second part deals with applications. First, the use of kappa symmetry to determine supersymmetric world volume solitons. This includes their explicit construction in flat and curved backgrounds, their interpretation as Bogomol’nyi–Prasad–Sommerfield (BPS) states carrying (topological) charges in the supersymmetry algebra and the connection between supersymmetry and Hamiltonian BPS bounds. When available, I emphasise the use of these solitons as constituents in microscopic models of black holes. Second, the use of probe approximations to infer about the non-trivial dynamics of strongly-coupled gauge theories using the anti de Sitter/conformal field theory (AdS/CFT) correspondence. This includes expectation values of Wilson loop operators, spectrum information and the general use of D-brane probes to approximate the dynamics of systems with small number of degrees of freedom interacting with larger systems allowing a dual gravitational description. Its final part briefly discusses effective actions for N D-branes and M2-branes. This includes both Super-Yang-Mills theories, their higher-order corrections and partial results in covariantising these couplings to curved backgrounds, and the more recent supersymmetric Chern–Simons matter theories describing M2-branes using field theory, brane constructions and 3-algebra considerations

Bovine oviductal and uterine fluid support in vitro embryo development

In order to mimic the maternal oviductal environment, we evaluated the effect of oviductal fluid (OF) and/or uterine fluid (UF) supplementation on in vitro embryo development and quality. In vitro-produced zygotes were cultured with 1.25% OF from Day 1 to Day 4 after insemination (OF group), 1.25% OF from Day 1 to Day 4 followed by 1.25% UF from Day 4 to Day 9 (OF+UF group) or 1.25% UF only from Day 4 to Day 9 (UF group). Control groups were cultured in the presence of synthetic oviduct fluid (SOF) supplemented with 3mgmL-1 bovine serum albumin (BSA) or 5% fetal calf serum (FCS). Supplementation of the culture medium with OF and/or UF (both at 1.25%) supported embryo development (Day 9 blastocyst rate 28.2-30.6%). At 72h after vitrification-warming, the survival of blastocysts from the OF and OF+UF groups was similar to that of blastocysts in the SOF+BSA group (61.0±5.7% and 62.8±6.4% vs 64.8±6.4% respectively), but significantly higher than that of blastocysts from the SOF+FCS group (31.6±4.9%; P<0.001). Blastocysts from the OF group exhibited upregulation of epigenetic genes (i.e. DNA methyltransferase 3α (DNMT3A) and insulin-like growth factor 2 receptor (IGF2R)), compared with expression in the SOF+FCS group (P<0.05). Whereas those from OF+UF and UF groups exhibited downregulation of oxidative stress genes compared to SOF+BSA and OF groups for glutathione peroxidase (GPX1) and to SOF+FCS, SOF+BSA and OF groups for chloride intracellular channel 1 (CLIC1) (P<0.05). In addition, accumulation of reactive oxygen species was lower in blastocysts from the OF, OF+UF and UF groups. In conclusion, the use of low concentrations of OF and UF in in vitro serum-free culture supports embryo development, with OF providing a better control of embryo methylation, whereas UF may have antioxidant activity