ABSTRACT
OBJECTIVE: Epidemiology studies indicate that green tea polyphenols (GTP) perform a protective effect on cardiovascular diseases, but the underlying mechanisms are complex. The present study aimed to investigate the effect of GTP on high-fat diets (HFD) induced-early vascular aging. METHODS: Six-week young adult Wistar rats were fed with standard chow or HFD in the presence and absence of GTP (200 mg/kg body weight) for 18 weeks. In vitro experiment, human umbilical vascular endothelial cells (HUVECs) were treated with palmitic acid (PA) and GTP. RESULTS: The results showed that GTP alleviated the disorganized arterial wall and the increased intima-media thickness induced by HFD. In addition, the vascular oxidative injury was suppressed following GTP treatment. Furthermore, GTP elevated the ratio of LC3-II/LC3-I and suppressed expression of p62/SQSTM1, and restored SIRT3 expression in the aorta of HFD rats. Consistently, in cultured HUVECs, GTP inhibited cell senescence indicated by SA-ß-gal and promoted endothelial autophagy compared with the PA treatment group. The activity of SIRT3 was specifically inhibited by 3-TYP, and the protective effect of GTP was consequently abolished. CONCLUSION: The findings indicated that GTP protected against early vascular senescence in young HFD rats via ameliorating oxidative injury and promoting autophagy which was partially regulated by the SIRT3 pathway.
Subject(s)
Diet, High-Fat , Sirtuin 3 , Animals , Rats , Aging , Antioxidants/pharmacology , Autophagy , Carotid Intima-Media Thickness , Diet, High-Fat/adverse effects , Endothelial Cells/metabolism , Guanosine Triphosphate/pharmacology , Palmitic Acid/pharmacology , Polyphenols/pharmacology , Rats, Wistar , Sequestosome-1 Protein/metabolism , Sirtuin 3/metabolism , Sirtuin 3/pharmacology , Tea/metabolismABSTRACT
Coherent XUV sources, which may operate at MHz repetition rate, could find applications in high-precision spectroscopy and for spatio-time-resolved measurements of collective electron dynamics on nanostructured surfaces. We theoretically investigate utilizing the enhanced plasmonic fields in an ordered array of gold nanoparticles for the generation of high-harmonic, extreme-ultraviolet (XUV) radiation. By optimization of the chirp of ultrashort laser pulses incident on the array, our simulations indicate a potential route towards the temporal shaping of the plasmonic near-field and, in turn, the generation of single attosecond pulses. The inherent effects of inhomogeneity of the local fields on the high-harmonic generation are analyzed and discussed. While taking the inhomogeneity into account does not affect the optimal chirp for the generation of a single attosecond pulse, the cut-off energy of the high-harmonic spectrum is enhanced by about a factor of two.
Subject(s)
Gold/chemistry , Lasers , Lighting/methods , Metal Nanoparticles/chemistry , Surface Plasmon Resonance/methods , Gold/radiation effects , Materials Testing , Metal Nanoparticles/radiation effects , Scattering, RadiationABSTRACT
We report on a high-power (cw) red laser at 671 nm by intracavity frequency doubling of a double-end-pumped 1342 nm Nd:YVO4 laser based on the nonlinear crystal LiB3O5. A red output power of 3.38 W is obtained for a pump power of 27 W, with corresponding optical-to-optical efficiency of 12.5%. The 671 nm beam is nearly diffraction limited.
