In Situ Characterization of 17-4PH Stainless Steel by Small-Angle Neutron Scattering.

17-4PH martensitic steel is usually used as valve stems in nuclear power plants and it suffers from thermal aging embrittlement due to long-time service in a high-temperature and high-pressure environment. Here, we characterized the evolution of microstructures at the nano-scale in 17-4PH steel by in situ small-angle neutron scattering (SANS) with a thermo-mechanically coupled loading device. The device could set different temperatures and tensile so that an in situ SANS experiment could dynamically characterize the process of nanoscale structural changes. The results showed that with increasing thermal aging time, the ε-Cu phase precipitates and grows as the temperature is 475 °C and 590 °C, and the ε-Cu phase is spherical at 475 °C but became elongated cylinders at 590 °C. Moreover, the loading stress could aid in the growth of the ε-Cu phase at 475 °C.

Development of a semi-empirical interatomic potential appropriate for the radiation defects in V-Ti-Ta-Nb high-entropy alloy.

High-entropy alloys (HEAs) hold promise as candidate structural materials in future nuclear energy systems. Body-centred cubic V-Ti-Ta-Nb HEAs have received extensive attention due to their excellent mechanical properties. In this work, the Finnis-Sinclair interatomic potential for quaternary V-Ti-Ta-Nb HEAs has been fitted based on the defect properties obtained with the density functional theory (DFT) calculations. The new potential for Nb accurately reproduces the vacancy formation energy, vacancy migration energy and interstitial formation energy. The typical radiation defect properties predicted by the alloy potential were consistent with the DFT results, including the binding energies between substitutional solute atoms, the binding energy between substitutional atoms and vacancies, and the formation energy of interstitial solute atoms. In addition, the mixing enthalpies of the alloys were also consistent with the DFT results. The present potential can also describe reasonably the collision cascade process of quaternary V-Ti-Ta-Nb HEAs.

High-frequency Repetitive Transcranial Magnetic Stimulation (rTMS) Accelerates onset Time of Beneficial Treating Effects and Improves Clinical Symptoms of Depression.

BACKGROUND: In recent years, more and more patients with depression demonstrate suicidal intention and suicidal behavior. OBJECTIVE: To evaluate the effectiveness of repetitive transcranial magnetic stimulation (rTMS) in treating depression with suicidal ideation. METHODS: Eighty-nine depression patients with suicide intention were administrated drugs combined with four weeks of Active rTMS (n=40) or sham (n=49) rTMS treatment. The 24-item Hamilton Depression Rating Scale for Depression (HAMD-24) and Self-rating Idea of Suicide Scale (SIOSS) were used to evaluate suicide risk and depression severity at baseline, weeks 2 and 4. A 25% reduction in HAMD-24 score from baseline was defined as treatment response. More than a 20% reduction in HAMD-24 score from baseline within the first 2 weeks of treatment was defined as an early improvement. RESULTS: No statistical significance was found for baseline sociodemographic and illness characteristics between the two groups (P >0.05). There was a significant difference for HAMD-24 and SIOSS scores between the two groups at weeks 2 and 4. Active rTMS group demonstrated a more significant score reduction compared to the Sham rTMS group at weeks 2 and 4. There was a significantly greater number of patients with early improvement observed in the Active rTMS group compared to those in the Sham rTMS group at weeks 2 (P <0.05). There was a significant difference in responder rates between the two groups at weeks 4 for HAMD-24 scores (P <0.05). CONCLUSION: rTMS could accelerate the onset time of beneficial treating effects and improve clinical symptoms of depression. During the treatment course, cognitive disorder, sleep disorder, anxiety/ somatization, retardation, and hopelessness symptoms were improved dramatically, and suicidal ideation was reduced.

The therapeutic effect of repetitive transcranial magnetic stimulation in elderly depression patients.

BACKGROUND: Depression, a common psychiatric disorder in elderly, serves as a remarkable precipitating factor for suicide among the elderly people. Here, a randomized double-blinded study was performed to investigate the efficacy of repetitive transcranial magnetic stimulation (rTMS) on improving the clinical symptoms and reducing suicidal ideation in elderly patients with depression. METHODS: In this study, 103 elderly patients with depression and suicidal ideation were randomly divided into 2 groups, 48 cases in the rTMS group and 55 cases in the control group (sham rTMS). Both groups received routine drug therapy with rTMS or sham rTMS. The patients received evaluation by Hamilton depression scale and self-rating idea of suicide scale before treatment and after 2 and 4 weeks of treatment, respectively. RESULTS: The measurement from the present study demonstrated that Hamilton depression scale and self-rating idea of suicide scale scores decreased to varying degrees in the 2 groups after treatment, and the decrease was more significant in rTMS group. The rate of marked effectiveness was much higher in rTMS group after 2 weeks of treatment compared with the control group. Furthermore, the rate of moderate effectiveness at 4 weeks after treatment was significantly higher in rTMS group compared with the control group. CONCLUSION: Together, the present study shows that rTMS with routine drug therapy exhibited effect with quick onset to improve the clinical symptoms and reduce suicidal ideation in elderly patients with depression.

Improved Dielectric Properties of Thermoplastic Polyurethane Elastomer Filled with Core-Shell Structured PDA@TiC Particles.

Insulating interlayer between nanoparticles and polymer matrix is crucial for suppressing the dielectric loss of polymer composites. In this study, titanium carbide (TiC) particles were surface modified by polydopamine (PDA), and the obtained PDA@TiC powders were used to reinforce thermoplastic polyurethane (TPU). The results indicate that the PDA@TiC were homogenously dispersed in the matrix compared with the pristine TiC, and that the PDA@TiC/TPU composites show improved dielectric and mechanical properties, i.e., much lower dissipation factors and obviously enhanced dielectric breakdown strength, as well as higher tensile strength and elongation at break as compared to the raw TiC/TPU. The nanoscale PDA interlayer contributes to the dielectric and mechanical enhancements because it not only serves as an insulating shell that prevents TiC particles from direct contacting and suppresses the loss and leakage current to very low levels, but also enhances the interfacial interactions thereby leading to improved mechanical strength and toughness. The prepared flexible PDA@TiC/TPU with high permittivity but low loss will find potential applications in electronic and electrical applications.