A new approach to improve the electrochemical performance of ZnMn2O4 through a charge compensation mechanism using the substitution of Al3+ for Zn2.

ZnMn2O4 and Zn1-x Al x Mn2O4 were synthesized by a spray drying process followed by an annealing treatment. Their structural and electrochemical characteristics were investigated by SEM, XRD, XPS, charge-discharge tests and EIS. XPS data indicate that the substitution of Al3+ for Zn2+ causes manganese to be in a mixed valence state by a charge compensation mechanism. Moreover, the presence of this charge compensation significantly improves the electrochemical performance of Zn1-x Al x Mn2O4, such as increasing the initial coulombic efficiency, stabilizing the cycleability as well as improving the rate capability. The sample with 2% Al doping shows the best performance, with a first cycle coulombic efficiency of 69.6% and a reversible capacity of 597.7 mA h g-1 after 100 cycles. Even at the high current density of 1600 mA g-1, it still retained a capacity of 558 mA h g-1.

Reliability and Validity of a Chinese Version of the Stroke Action Test: A New Instrument for Assessment of Stroke Knowledge and Response.

BACKGROUND: The public's cognition of stroke and responses to stroke symptoms are important to prevent complications and decrease the mortality when stroke occurs. The aim of study was to develop and validate the Chinese version of the Stroke Action Test (C-STAT) in a Chinese population. METHODS: This study was rigorously implemented with the published guideline for the translation, adaptation and validation of instruments for the cross-cultural use in healthcare care research. A cross-sectional study was performed among 328 stroke patients and family members in the Department of Neurology in the Second Hospital of Lanzhou University, Gansu province, China in 2014. RESULTS: The Chinese version of the instrument showed favorable content equivalence with the source version. Values of Cronbach's alpha and test-retest reliability of the C-STAT were 0.88 and 0.86, respectively. Principal component analysis supported four-factor solutions of the C-STAT. Criterion-related validity showed that the C-STAT was a significant predictor of the 7-item stroke symptom scores (R = 0.77; t = 21.74, P< 0.001). CONCLUSION: The C-STAT is an intelligible and brief psychometrical tool to assess individuals' knowledge of the appropriate responses to stroke symptoms in Chinese populations. It could also be used by health care providers to assess educational programs on stroke prevention.