Nebivolol improves diastolic dysfunction and myocardial remodeling through reductions in oxidative stress in the transgenic (mRen2) rat

Angiotensin II contributes to myocardial tissue remodeling and interstitial fibrosis through NADPH oxidase-mediated generation of oxidative stress in the progression of heart failure. Recent data have suggested that nebivolol, a third-generation β-blocker, improves diastolic dysfunction by targeting nitric oxide (NO) and metabolic pathways that decrease interstitial fibrosis. We sought to determine if targeting NO would improve diastolic function in a model of tissue renin-angiotensin system overactivation. We used the transgenic (TG) (mRen2)27 rat, which overexpresses the murine renin transgene and manifests insulin resistance and left ventricular dysfunction. We treated 6- to 7-wk-old TG (mRen2)27 rats and age-matched Sprague-Dawley control rats with nebivolol (10 mg·kg(-1)·day(-1)) or placebo via osmotic minipumps for a period of 21 days. Compared with Sprague-Dawley control rats, TG (mRen2)27 rats displayed a prolonged diastolic relaxation time and reduced initial filling rate associated with increased interstitial fibrosis and left ventricular hypertrophy. These findings were temporally related to increased NADPH oxidase activity and subunits p47(phox) and Rac1 and increased total ROS and peroxynitrite formation in parallel with reductions in the antioxidant heme oxygenase as well as the phosphorylation/activation of endothelial NO synthase and PKB/Akt. Treatment with nebivolol restored diastolic function and interstitial fibrosis through increases in the phosphorylation of 5'-AMP-activated protein kinase, Akt, and endothelial NO synthase and reductions in oxidant stress. These results support that targeting NO with nebivolol treatment improves diastolic dysfunction through reducing myocardial oxidative stress by enhancing 5'-AMP-activated protein kinase and Akt activation of NO biosynthesis.     

Study of Pyrex and quartz insulators contamination effect on the X-ray intensity in a 4-kJ plasma focus device

The variation of the X-ray intensity has been investigated with the Pyrex and quartz insulators surface contamination in a 4-kJ plasma focus device with argon gas at 11.5-kV charging voltage. Elemental analysis (EDAX) showed that the Cu evaporated from the electrode material and was deposited on the sleeve surface improves the breakdown conditions. A small level of sleeve contamination by copper is found to be essential for good focusing action and high HXR intensity. The SEM imaging showed the grain-type structure of Cu formed on the surface and it changed the surface property. Resistance measurements of original and coated Pyrex surface proved that the copper deposition on the sleeve surface will reduce its resistance as compared to the almost infinitely large resistance of the uncontaminated sleeve. As the contamination is surpassed to some critical level, the HXR intensity from the device is deteriorated.     

Constructing circular phylogenetic networks from weighted quartets using simulated annealing

In this paper, we present a heuristic algorithm based on the simulated annealing, SAQ-Net, as a method for constructing phylogenetic networks from weighted quartets. Similar to QNet algorithm, SAQ-Net constructs a collection of circular weighted splits of the taxa set. This collection is represented by a split network. In order to show that SAQ-Net performs better than QNet, we apply these algorithm to both the simulated and actual data sets containing salmonella, Bees, Primates and Rubber data sets. Then we draw phylogenetic networks corresponding to outputs of these algorithms using SplitsTree4 and compare the results. We find that SAQ-Net produces a better circular ordering and phylogenetic networks than QNet in most cases. SAQ-Net has been implemented in Matlab and is available for download at http://bioinf.cs.ipm.ac.ir/softwares/saq.net.     

Conodont biostratigraphy of the Upper Devonian-Lower Carboniferous Shahmirzad section, central Alborz, Iran

The conodont fauna from the Devonian-Carboniferous Shahmirzad section, located in the Central Alborz Mountains (North Iran), have been studied mainly for biostratigraphic purposes. Some levels were barren of conodonts, whereas others yielded a not very abundant, but quite differentiated fauna. No conodonts have been found from the mainly terrigenous and shaly Geirud Formation, whereas representative of genera Bispathodus, Clydagnathus, Gnathodus, Hindeodus, Mehlina, Polygnathus, Protognathodus, Pseudopolygnathus and Siphonodella have been collected from the mainly calcareous overlaying Mobarak Formation. The fauna allowed to discriminate five biointervals, from the sulcata Zone to a “Lower typicus - anchoralis-latus interval” in the central part of the section, while the lower and upper parts cannot be zoned on the basis of conodonts. This paper is the first report on lowermost Carboniferous conodonts from the Mobarak Formation in central Alborz.     

Isolation and structure of D-xylans from pericarp seeds of Opuntia ficus-indica prickly pear fruits

Xylans were isolated from the pericarp of prickly pear seeds of Opuntia ficus-indica (OFI) by alkaline extraction, fractionated by precipitation and purified. Six fractions were obtained and characterized by sugar analysis and NMR spectroscopy. They were assumed to be (4-O-methyl-D-glucurono)-D-xylans, with 4-O-alpha-D-glucopyranosyluronic acid groups linked at C-2 of a (1-->4)-beta-D-xylan. The sugar composition and the 1H and 13C NMR spectra showed that their chemical structures were very similar, but with different proportions of D-Xyl and 4-O-Me-D-GlcA. Our results showed that, on average, the water soluble xylans have one nonreducing terminal residue of 4-O-methyl-D-glucuronic acid for every 11 to 14 xylose units, whereas in the water non-soluble xylans, xylose units can varied from 18 to 65 residues for one nonreducing terminal residue of 4-O-methyl-D-glucuronic acid.