In patients with NVAF, D-dimer may be helpful for predicting the absence of LAA thrombi. D-dimer level was clinically useful to guide the management of patients with NVAF, especially for those complicated with congestive heart failure and/or recent embolic events.

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Magnetization measurements under hydrostatic pressure were performed on an S ¼ 1=2 coupled spin dimer system TlCuCl 3 with a gapped ground state under magnetic field H parallel to the ½201 direction. With increasing applied pressure P, the gap decreases and closes completely at P c ¼ 0:42 AE 0:05 kbar. For P > P c , TlCuCl 3 undergoes antiferromagnetic ordering. A spin-flop transition was observed at H sf ' 0:7 T. The spin-flop field is approximately independent of pressure, although the sublattice magnetization increases with pressure. The gap and Néel temperature are presented as functions of pressure. The occurrence of the pressure-induced quantum phase transition is attributed to the relative enhancement of the interdimer exchange interactions compared with the intradimer exchange interaction. A quantum phase transition (QPT) is a phase transition between different quantum ground states induced by a continuous change in interaction constants or applied field. 1)In the vicinity of the transition point called the quantum critical point (QCP), physical properties are governed by quantum fluctuations. Novel ground states are stabilized by quantum fluctuations and the critical behavior associated with QPT is of current interest in condensed matter physics. In this letter, we report on the magnetic QPT induced by the applied pressure in the coupled spin dimer system TlCuCl 3 .TlCuCl 3 crystallizes in a monoclinic structure, 2) which is the same as the structure of KCuCl 3 .3) The crystal structure consists of planar dimers of Cu 2 Cl 6 , in which Cu 2þ ions have spin 1=2. The magnetic ground state is a spin singlet with an excitation gap of Á=k B ¼ 7:5 K.2,4,5) The origin of the spin gap is the antiferromagnetic exchange interaction J=k B ¼ 65:9 K on the planar dimer Cu 2 Cl 6 . 6,7) The markedly small gap as compared with the intradimer exchange interaction J is ascribed to strong interdimer exchange interactions with the three-dimensional network.Because of the small gap, the field-induced magnetic QPT from the gapped spin liquid state to the antiferromagnetic state with transverse-ordered moments can be observed in TlCuCl 3 using a conventional superconducting magnet. 5)Thus, the static and dynamic properties of the field-induced magnetic QPT have been extensively investigated in various experiments.8-10) The results were clearly described in terms of the Bose-Einstein condensation of spin triplets called magnons or triplons. [10][11][12][13] It is considered that the application of hydrostatic pressure enhances interdimer interactions, because the distances between dimers are contracted. Since the spin gap shrinks with increasing the magnitude of interdimer interactions, and, in general, the effect of pressure on exchange interactions is fairly large in chlorides, we can expect the occurence of a pressure-induced magnetic QPT in the pressure range of P < 10 kbar, which is easily accessible with a high-pressure cramp cell. With this reasoning, we performed magnetization measurements on TlCuCl 3 under hydrostati...

Magnetic measurements under high pressures have been performed on the hexagonal ABX3 type antiferromagnets, CsFeCl3, CsNiCl3 and RbNiCl3 to investigate the pressure effect on the magnetic phase transitions. CsFeCl3 has the singlet ground state due to the large single-ion anisotropy of the easy-plane type at ambient pressure. Above the critical pressure Pc 0.9 GPa, CsFeCl3 exhibits the long range magnetic ordering at zero field as the result of the collapse of the energy gap between the singlet state and the lowest excited doublet. CsNiCl3 and RbNiCl3 having the easy-axis type magnetic anisotropy undergo the successive phase transitions in the temperature variations and exhibit the spin-flop phase transition in the field parallel to the c-axis. With increasing pressure, the temperature range of the collinear intermediate phase and the spin-flop field HSF are enhanced. This fact indicates that the easy-axis anisotropies of CsNiCl3 and RbNiCl3 are enhanced by the pressure as compared with the increase of the intra-and inter-chain interactions. * )