Efficacy of suprascapular nerve blocks for management of hemiplegic shoulder pain: a systematic review and meta-analysis.

OBJECTIVE: To compare the efficacy of suprascapular nerve block (SSNB) with other treatment modalities for management of HSP in terms of relieving pain and improving range of motion of shoulder joints. MATERIALS AND METHODS: An electronic search was carried out in PubMed, CENTRAL, SCOPUS and EMBASE databases using a series of relevant keywords, along with a manual search. Randomized clinical trials comparing the efficacy of SSNB with placebo injections, intra-articular injections (IAI), ultrasound and Pulsed RF were identified. The outcomes assessed were pain relief measured with visual analogue scale and improvement in the range of motion (ROM) at the end of the follow-up period. The meta-analysis was carried out for quantitative analysis of outcome data. RESULTS: Eight randomized clinical trials were included. The quality of the included trials was low to moderate. SSNB showed improved pain relief at the end of 1 month, compared to placebo (normal saline injections) with mean difference (MD) 1.20 95% CI [0.59,1.80], p<0.0001. When compared to Pulsed radio-frequency (RF), the pain relief at the end of 1 month and 3 months was greater for patients treated with Pulsed RF than SSNB. No significant improvement in the range of motion for flexion, external and internal rotation was observed between SSNB and inter-articular injections. CONCLUSIONS: SSNB is more effective in pain relief than placebo injections and ultrasound, but similar to pulsed RF. Similar effectiveness in ROM improvement was observed with SSNB and intra-articular injections.

Universality classes of the domain-wall creep motion driven by spin-transfer torques.

With the stochastic Landau-Lifshitz-Gilbert equation, we numerically simulate the creep motion of a magnetic domain wall driven by the adiabatic and nonadiabatic spin-transfer torques induced by the electric current. The creep exponent µ and the roughness exponent ζ are accurately determined from the scaling behaviors. The creep motions driven by the adiabatic and nonadiabatic spin-transfer torques belong to different universality classes. The scaling relation between µ and ζ based on certain simplified assumptions is valid for the nonadiabatic spin-transfer torque, while invalid for the adiabatic one. Our results are compatible with the experimental ones, but go beyond the existing theoretical prediction. Our investigation reveals that the disorder-induced pinning effect on the domain-wall rotation alters the universality class of the creep motion.

Spin-reorientation critical dynamics in the two-dimensional XY model with a domain wall.

In recent years, static and dynamic properties of non-180^{∘} domain walls in magnetic materials have attracted a great deal of interest. In this paper, spin-reorientation critical dynamics in the two-dimensional XY model is investigated with Monte Carlo simulations and theoretical analyses based on the Langevin equation. At the Kosterlitz-Thouless phase transition, the dynamic scaling behaviors of the magnetization and the two-time correlation function are carefully analyzed, and critical exponents are accurately determined. When the initial value of the angle between adjacent domains is slightly lower than π, a critical exponent is introduced to characterize the abnormal power-law increase of the magnetization in the horizontal direction inside the domain interface, which is measured to be ψ=0.0568(8). In addition, the relation ψ=η/2z is analytically deduced from the Langevin dynamics in the long-wavelength approximation, well consistent with numerical results.

Numerical simulations of critical dynamics in anisotropic magnetic films with the stochastic Landau-Lifshitz-Gilbert equation.

With the stochastic Landau-Lifshitz-Gilbert (sLLG) equation, critical dynamic behaviors far from equilibrium or stationary around the order-disorder and pinning-depinning phase transitions in anisotropic magnetic films are investigated. From the dynamic relaxation with and without an external field, the Curie temperature and critical exponents of the order-disorder phase transition are accurately determined. For the pinning-depinning phase transition induced by quenched disorder, the nonstationary creep motion of domain wall activated by finite temperatures is simulated, and the thermal rounding exponent is extracted. The results show that the dynamic universality class of the sLLG equation is different from those of the Monte Carlo dynamics and quenched Edwards-Wilkinson equation, and it may lead to alternative understanding of experiments. The dynamic approach shows its great efficiency for the sLLG equation.

Nonsteady dynamic properties of a domain wall for the creep state under an alternating driving field.

With Monte Carlo simulations, the nonsteady dynamic properties of a domain wall have been systematically investigated for the thermally activated creep state under an alternating driving field. Taking the driven random-field Ising model in two dimensions as an example, two distinct growth stages of the domain interface are identified with both the correlation length and roughness function. One stage belongs to the universality class of the random depositions, and the other to that of the quenched Edwards-Wilkinson equation. In the latter case, due to the dynamic effect of overhangs, the domain interface may exhibit an intrinsic anomalous scaling behavior, different from that of the quenched Edwards-Wilkinson equation.

Dynamic approach to finite-temperature magnetic phase transitions in the extended J1-J2 model with vacancy order.

The recently discovered iron-based superconductors A(y)Fe(2-x)Se(2) (A=K, Rb, Cs, Tl) show a long-range antiferromagnetic order with an unexpectedly high transition temperature T(N)~550 K and a unique √5×√5 vacancy order. Taking the extended J(1)-J(2) model as a minimal model, we investigate the finite-temperature magnetic phase transitions in a square lattice with a √5×√5 vacancy superstructure by using large-scale Monte Carlo simulations. By the parallel tempering technique, the block spin checkerboard and stripe antiferromagnetic states are detected to be the ground states for three representative sets of model parameters. The short-time dynamic approach is applied to accurately determine the critical temperature as well as the static and dynamic exponents. Our results indicate that the dramatic enhancement of the critical temperature as observed in experiments should be mainly due to a combination of the vacancy order and the block lattice contraction.

Sex differences in ICR mice in the Morris water maze task.

The Morris water maze (MWM) is one of the most common tasks used to assess spatial learning and memory ability in rodents. Genetic strain and gender are two prominent variants that influence spatial performance. Although it was reported that ICR (Institute of Cancer Research) mice exhibited an unchanged baseline performance in the training phase of the MWM task, this outbred strain has been widely used in learning and memory studies, and little is known regarding the effects of sex on behavioral performance. In this study, we demonstrated that both male and female ICR mice could complete the MWM task. Furthermore, a significant sex difference was observed, with females having shorter escape latencies and longer durations in the target quadrant in both the acquisition and test phases. Our findings emphasize the necessity of careful examination of not only the strain effect on behavioral performance but also the sex effect.

Depinning phase transition in the two-dimensional clock model with quenched randomness.

With Monte Carlo simulations, we systematically investigate the depinning phase transition in the two-dimensional driven random-field clock model. Based on the short-time dynamic approach, we determine the transition field and critical exponents. The results show that the critical exponents vary with the form of the random-field distribution and the strength of the random fields, and the roughening dynamics of the domain interface belongs to the new subclass with ζ≠ζ(loc)≠ζ(s) and ζ(loc)≠1. More importantly, we find that the transition field and critical exponents change with the initial orientations of the magnetization of the two ordered domains.

Dynamic effect of overhangs and islands at the depinning transition in two-dimensional magnets.

With the Monte Carlo methods, we systematically investigate the short-time dynamics of domain-wall motion in the two-dimensional random-field Ising model with a driving field (DRFIM). We accurately determine the depinning transition field and critical exponents. Through two different definitions of the domain interface, we examine the dynamics of overhangs and islands. At the depinning transition, the dynamic effect of overhangs and islands reaches maximum. We argue that this should be an important mechanism leading the DRFIM model to a different universality class from the Edwards-Wilkinson equation with quenched disorder.

Critical domain-wall dynamics of model B.

With Monte Carlo methods, we simulate the critical domain-wall dynamics of model B, taking the two-dimensional Ising model as an example. In the macroscopic short-time regime, a dynamic scaling form is revealed. Due to the existence of the quasirandom walkers, the magnetization shows intrinsic dependence on the lattice size L . An exponent which governs the L dependence of the magnetization is measured to be sigma=0.243(8) .

Logarithmic correction to scaling in domain-wall dynamics at Kosterlitz-Thouless phase transitions.

With Monte Carlo simulations, we investigate the relaxation dynamics of domain walls at the Kosterlitz-Thouless phase transition, taking the two-dimensional XY model as an example. The dynamic scaling behavior is carefully analyzed, and a domain-wall roughening process is observed. Two-time correlation functions are calculated and aging phenomena are investigated. Inside the domain interface, a strong logarithmic correction to scaling is detected.

Nonequilibrium critical dynamics with domain wall and surface.

With Monte Carlo simulations, we investigate the relaxation dynamics with a domain wall for magnetic systems at the critical temperature. The dynamic scaling behavior is carefully analyzed, and a dynamic roughening process is observed. For comparison, similar analysis is applied to the relaxation dynamics with a free or disordered surface.