scholarly journals Nuclear Spin Relaxation of Longitudinal and Singlet Order in Liquid-CO2 Solutions

2021 ◽  
Vol 9 ◽  
Author(s):  
Aliki Moysiadi ◽  
Francesco Giustiniano ◽  
Andrew M. R. Hall ◽  
Topaz A. A. Cartlidge ◽  
Lynda J. Brown ◽  
...  

Hyperpolarization techniques can enormously enhance the NMR signal thus allowing the exploitation of hyperpolarized substrates for in-vivo MRI applications. The short lifetime of hyperpolarized spin order poses significant limitations in such applications. Spin order storage can be prolonged through the use of long-lived spin states. Additionally, the storage of spin polarization–either in the form of longitudinal or singlet order–can be prolonged in low viscosity solutions. Here, we report the use of low viscosity liquid-CO2 solutions to store nuclear spin polarization in the form of longitudinal and singlet order for extended periods. Our results demonstrate that this storage time can be considerably sustained in liquid-CO2 solutions in comparison to other low viscosity solvents, opening up the possibility of new, exciting storage experiments in the future.

2011 ◽  
Author(s):  
Takashi Nakajima ◽  
Yasuko Kobayashi ◽  
Susumu Komiyama ◽  
Jisoon Ihm ◽  
Hyeonsik Cheong

Author(s):  
M. M. Glazov

The transfer of nonequilibrium spin polarization between the electron and nuclear subsystems is studied in detail. Usually, a thermal orientation of nuclei in magnetic field is negligible due to their small magnetic moments, but if electron spins are optically oriented, efficient nuclear spin polarization can occur. The microscopic approach to the dynamical nuclear polarization effect based on the kinetic equation method, along with a phenomenological but very powerful description of dynamical nuclear polarization in terms of the nuclear spin temperature concept is given. In this way, one can account for the interaction between neighbouring nuclei without solving a complex many-body problem. The hyperfine interaction also induces the feedback of polarized nuclei on the electron spin system giving rise to a number of nonlinear effects: bistability of nuclear spin polarization and anomalous Hanle effect, dragging and locking of optical resonances in quantum dots. Theory is illustrated by experimental data on dynamical nuclear polarization.


Author(s):  
Akiyoshi Shimatani ◽  
Hiromitsu Toyoda ◽  
Kumi Orita ◽  
Yuta Ibara ◽  
Yoshiyuki Yokogawa ◽  
...  

AbstractThis study investigated whether mixing low viscosity alginic acid with calcium phosphate cement (CPC) causes interconnected porosity in the CPC and enhances bone replacement by improving the biological interactions. Furthermore, we hypothesized that low viscosity alginic acid would shorten the setting time of CPC and improve its strength. CPC samples were prepared with 0, 5, 10, and 20% low viscosity alginic acid. After immersion in acetate buffer, possible porosification in CPC was monitored in vitro using scanning electron microscopy (SEM), and the setting times and compressive strengths were measured. In vivo study was conducted by placing CPC in a hole created on the femur of New Zealand white rabbit. Microcomputed tomography and histological examination were performed 6 weeks after implantation. SEM images confirmed that alginic acid enhanced the porosity of CPC compared to the control, and the setting time and compressive strength also improved. When incorporating a maximum amount of alginic acid, the new bone mass was significantly higher than the control group (P = 0.0153). These biological responses are promising for the translation of these biomaterials and their commercialization for clinic applications.


2016 ◽  
Vol 93 (8) ◽  
Author(s):  
F. Heisterkamp ◽  
E. Kirstein ◽  
A. Greilich ◽  
E. A. Zhukov ◽  
T. Kazimierczuk ◽  
...  

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