Dynamic switching of the spin circulation in tapered magnetic nanodisks

Magnetic vortices are characterized by the sense of in-plane magnetization circulation and by the polarity of the vortex core. With each having two possible states, there are four possible stable magnetization configurations that can be utilized for a multibit memory cell. Dynamic control of vortex core polarity has been demonstrated using both alternating and pulsed magnetic fields and currents. Here, we show controlled dynamic switching of spin circulation in vortices using nanosecond field pulses by imaging the process with full-field soft X-ray transmission microscopy. The dynamic reversal process is controlled by far-from-equilibrium gyrotropic precession of the vortex core, and the reversal is achieved at significantly reduced field amplitudes when compared with static switching. We further show that both the field pulse amplitude and duration required for efficient circulation reversal can be controlled by appropriate selection of the disk geometry.

Association of angiotensin I-converting enzyme gene insertion/deletion polymorphism and IgA nephropathy: a meta-analysis

BACKGROUND/AIMS

The angiotensin I-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been extensively examined for the association with immunoglobulin A (IgA) nephropathy (IgAN), however, conflicting results have occurred. We performed a meta-analysis to evaluate the association of ACE I/D polymorphism with IgAN in different ethnic groups.

METHODS

11 studies testing the association between ACE I/D polymorphism and IgAN susceptibility, and 9 studies testing the association of ACE I/D with IgAN progression were used in this analysis. The overall odds ratio (OR) was estimated by a fixed or random effect model.

RESULTS

The overall OR for the risk of susceptibility and progression of IgAN in Asians for the DD genotype is 2.37 (95% CI 1.04-5.41) and 1.75 (95% CI 1.24-2.56). The overall OR for the D allele in Asians also showed a similar magnitude, though without statistical significance (p = 0.09, p = 0.13, respectively). In Caucasians, both the DD genotype and D allele were associated with IgAN progression (OR 1.90, 1.61, respectively), but not IgAN susceptibility (p = 0.30, p = 0.41, respectively).

CONCLUSION

Our findings support the notion that ACE I/D polymorphism is associated with IgAN. Meanwhile, the role of ACE I/D polymorphism in Asians is different from that of Caucasians.

Mechanisms underlying the induction of vasorelaxation in rat thoracic aorta by sanguinarine

In the present study, the effect of sanguinarine (SANG) on smooth muscle was investigated in thoracic aorta isolated from rats. SANG dose-dependently relaxed the phenylephrine (PE, 3 microM)-precontracted aorta; and the concentrations to produce 50% relaxation were 3.18 +/- 0.37 and 3.42 +/- 1.14 microM, respectively, in intact and denuded aorta. These results suggest that the relaxing effect of SANG was endothelium-independent. The total contraction induced by PE was inhibited in aorta pretreated with SANG at microM concentration. Both phasic and tonic contractions induced by PE were inhibited by SANG independently, which were further supported by the fact that inositol 1,4,5-trisphosphate (IP3) formation and 45Ca2+ influx induced by 3 microM PE in denuded aorta were inhibited by SANG concentration-dependently. In addition, the vasocontraction induced by high-K+ was also inhibited by SANG, however, at higher concentrations. The inhibitory effects of SANG were reversed by dithiothreitol, a thiol reducing agent, implying that the oxidation of critical sulfhydryl groups on key molecules that regulate the smooth muscle contraction were involved. These data suggested that the inhibitory effects of SANG on PE-induced vasocontraction might involve the inhibition of IP3 formation and blockade of calcium channel.