Current status of the research on transparent YAG ceramics as laser hosts from an Italian network

This work describes the results obtained using two different processing systems for the production of YAG based ceramics. One involves the use of commercially available oxide powders (Yb2O3, Y2O3, Al2O3) The other involves the use of Yb-doped Y2O3 (Yb, 9.8%) powders obtained by microwave assisted co-precipitation from salts solution and a commercial alumina (Al2O3). Both systems are processed by wet mechanical mixing of starting oxides and reactive sintering of the obtained mixtur

3-D numerical simulation of Yb:YAG active slabs with longitudinal doping gradient for thermal load effects assessment.

We present a study of Yb:YAG active media slabs, based on a ceramic layered structure with different doping levels. We developed a procedure allowing 3D numerical analysis of the slab optical properties as a consequence of the thermal load induced by the pump process. The simulations are compared with a set of experimental results in order to validate the procedure. These structured ceramics appear promising in appropriate geometrical configurations, and thus are intended to be applied in the construction of High Energy Diode Pumped Solid State Laser (DPSSL) systems working in high repetition-rate pulsed regimes. (C) 2014 Optical Society of Americ

Gene silencing of endothelial von Willebrand Factor attenuates angiotensin II-induced endothelin-1 expression in porcine aortic endothelial cells.

Expression of endothelin (ET)-1 is increased in endothelial cells exposed to angiotensin II (Ang II), leading to endothelial dysfunction and cardiovascular disorders. Since von Willebrand Factor (vWF) blockade improves endothelial function in coronary patients, we hypothesized that targeting endothelial vWF with short interference RNA (siRNA) prevents Ang II-induced ET-1 upregulation. Nearly 65 ± 2% silencing of vWF in porcine aortic endothelial cells (PAOECs) was achieved with vWF-specific siRNA without affecting cell viability and growth. While showing ET-1 similar to wild type cells at rest, vWF-silenced cells did not present ET-1 upregulation during exposure to Ang II (100 nM/24 h), preserving levels of endothelial nitric oxide synthase activity similar to wild type. vWF silencing prevented AngII-induced increase in nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) activity and superoxide anion (O2-) levels, known triggers of ET-1 expression. Moreover, no increase in O2- or ET-1 levels was found in silenced cells treated with AngII or NOX-agonist phorbol ester (PMA 5 nM/48 h). Finally, vWF was required for overexpression of NOX4 and NOX2 in response to AngII and PMA. In conclusion, endothelial vWF knockdown prevented Ang II-induced ET-1 upregulation through attenuation of NOX-mediated O2- production. Our findings reveal a new role of vWF in preventing of Ang II-induced endothelial dysfunction

Quantifying partial hole-particle distance at the excited state: A revised version of the DCT index

International audienc

Exosomes released from sulforaphane-treated fibroblasts protect the cardiomyocytes from angiotensin II-induced hypertrophy

Introduction: The communication between fibroblasts and cardiomyocytes underlies the pathological cardiac hypertrophy induced by angiotensin-II (AngII), which contributes to heart failure. Fibroblast-derived exosomes (F-Exo) have been implicated in mediating AngII-induced cardiomyocyte hypertrophy. However, how release of anti-hypertrophic F-Exo is induced, remains an unanswered issue. Sulforaphane (SFN), a naturally occurring isothiocyanate extracted from cruciferous vegetables, attenuates AngII-induced cardiomyocytes hypertrophy. We tested the effects of SFN on the release of anti-hypertrophic F-Exo in vitro. Methods: Murine embryo fibroblasts were treated with non-toxic dose of SFN (3 μM/7 days). Intact F-Exo were isolated from cell culture media by differential centrifugation. F-Exo were quantified by Western blot using CD63. Hypertrophy of HL-1 cardiomyocytes was induced by AngII (100 nM/12 h). Cell viability was assessed by MTT assay. Cell surface area, an indicator of cell hypertrophy, was measured after 3 or 24 h incubation with 30 μg exosomes isolated from SFN-treated (SFN-F-Exo) or untreated (F-Exo, control) fibroblasts. Uptake by HL-1 of DiA-labeled exosomes was measured under rest or AngII. Exosomal content of Maspin, a protease inhibitor with function of inhibitor of histone deacetylase 1, was assessed by Western blot. Results: Treatment with F-Exo significantly increased HL-1 viability by 53% under stress compared to control. Stressed HL-1 treated for 24 h with SFN-F-Exo displayed cell surface area similar to resting cells, but not those treated with F-Exo. Stressed HL-1 exhibited a ~3-fold increase in SFN-F-Exo uptake rather than F-Exo. SFN-F-Exo are enriched in Maspin. Summary/conclusion: SFN increases the uptake of F-Exo which display the ability to prevent AngII-induced cardiomyocytes hypertrophy. Higher content of Maspin in SFN-F-Exo suggests that modulation of exosomal uptake and hypertrophy in stressed cardiomyocytes may be epigenetically driven

Epigenetic regulation of myocardial homeostasis, self-regeneration and senescence

The adult myocardium has limited capacity to preserve, renew or rejuvenate itself. The local microenvironment may induce epigenetic changes affecting the survival, proliferation, function and senescence of cardiac cells at rest and following the exposure to different stressors. The cellular response to microenvironment is characterized by the release of ions, oxygen free radicals, auto/paracrine factors and RNAs that drive the magnitude of gene reprogramming through the interaction with specific promoters. The epigenetic alterations may act at transcriptional and post-transcriptional level and change cardiac physiological traits. The abnormal DNA methylation underlies the progressive decay of contractile function and the angiogenic ability; while, the histone acetylation promotes the survival, function and proliferation of cardiac cells in the presence of ischemic microenvironment. At least, the expression and secretion of microRNAs and long noncoding RNAs may regulate the threshold to stress tolerance of adult cardiac cells and induce the matrix turnover as well. Natural or synthetic active compounds effectively modulate the epigenetic state of cardiac cells. Plant foods contain many active compounds with epigenetic properties and might assume a clinical significance as natural cardiac regenerators or rejuvenators. Our review describes novel epigenetic mechanisms that underpin myocardial remodeling, repair/ regeneration or senescence in order to support the development of most effective and reproducible rescue therapy of adult heart

Excited state tracking during the relaxation of coordination compounds

International audienceThe ability to locate minima on electronic excited states (ESs) potential energy surfaces both in the case of bright and dark states is crucial for a full understanding of photochemical reactions. This task has become a standard practice for small-to medium-sized organic chromophores thanks to the constant developments in the field of computational photochemistry. However, this remains a very challenging effort when it comes to the optimization of ESs of transition metal complexes (TMCs), not only due to the presence of several electronic ESs close in energy, but also due to the complex nature of the ESs involved. In this article, we present a simple yet powerful method to follow an ES of interest during a structural optimization in the case of TMCs, based on the use of a compact hole-particle representation of the electronic transition, namely the natural transition orbitals (NTOs). State tracking using NTOs is unambiguously accomplished by computing the mono-electronic wave function overlap between consecutive steps of the optimization. Here, we demonstrate that this simple but robust procedure works not only in the case of the cytosine but also in the case of the ES optimization of a ruthenium nitrosyl complex which is very problematic with standard approaches