University of Tsukuba

About: University of Tsukuba is a education organization based out in Tsukuba, Ibaraki, Japan. It is known for research contribution in the topics: Population & Gene. The organization has 36352 authors who have published 79483 publications receiving 1934752 citations. The organization is also known as: Tsukuba daigaku & Tsukuba University.

Nanoscale nuclear magnetic resonance with chemical resolution

Abstract: Nuclear magnetic resonance (NMR) spectroscopy is a key analytical technique in chemistry, biology, and medicine However, conventional NMR spectroscopy requires an at least nanoliter-sized sample volume to achieve sufficient signal We combined the use of a quantum memory and high magnetic fields with a dedicated quantum sensor based on nitrogen vacancy centers in diamond to achieve chemical shift resolution in 1H and 19F NMR spectroscopy of 20-zeptoliter sample volumes We demonstrate the application of NMR pulse sequences to achieve homonuclear decoupling and spin diffusion measurements The best measured NMR linewidth of a liquid sample was ~1 part per million, mainly limited by molecular diffusion To mitigate the influence of diffusion, we performed high-resolution solid-state NMR by applying homonuclear decoupling and achieved a 20-fold narrowing of the NMR linewidth

Endogenous endothelin-1 participates in the maintenance of cardiac function in rats with congestive heart failure : Marked increase in endothelin-1 production in the failing heart

Abstract: Background Although it was demonstrated that circulating endothelin-1 (ET-1) levels are elevated in congestive heart failure (CHF), the production and roles of ET-1 in the failing heart are not known. We investigated the production of ET-1 in the heart and the density of myocardial ET receptors in rats with CHF. We also investigated the effects of intravenously infused BQ-123, an endothelinA (ETA) receptor antagonist, on both heart rate and myocardial contractility in rats with CHF. Methods and Results We used the left coronary artery–ligated rat model of CHF (CHF rats). Three weeks after surgery, the rats developed CHF. Plasma ET-1 concentration was significantly higher in the CHF rats than in the sham-operated rats (P<.01). In the left ventricle, the expression of prepro–ET-1 mRNA was markedly higher in the CHF rats than in the sham-operated rats. The peptide level of ET-1 in the left ventricle was also significantly higher in the CHF rats than in the sham-operated rats (500±41 versus 102±10 pg/g tissue...