RESUMO
This paper examines possible causes, consequences, and potential solutions for addressing vaccine hesitancy in the United States, focusing on the perspectives of academic scientists. By examining the experiences of scientists, who are arguably a critical community in US society, we gain deeper insights into how they understand the complexities of vaccine hesitancy and whether their insights and opinions converge with or diverge from the current literature. We present findings from a national survey of a representative sample of academic scientists from the fields of biology and public health regarding vaccine hesitancy and related topics. Empirical analysis using descriptive, bivariate, and multivariate analyses covers multiple topics, including vaccine controversy, trust in science, causes of vaccine hesitancy, preferred policy and regulatory approaches, risk perceptions, and scientists' ethics and perceived communication roles. The results highlight a diversity of opinions within the scientific community regarding how to improve science-society communication in regard to vaccines, including the need to be transparent and candid to the public about the risk of vaccines and their research.
RESUMO
As one of the key factors that affect the application of hydrazine hydrate as a potential hydrogen source, efficient and cheap catalyst is particularly important. Nickel based catalysts have been widely studied because of their excellent catalytic performance for the decomposition of hydrazine hydrate to hydrogen. Herein, a Ni catalyst supported on anatase TiO2 through reduction and impregnation methods was prepared. Structure of the catalyst was investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), and X-ray photoelectron spectroscopy (XPS). The effects of the amount of TiO2 and the concentration of NaOH on the activity of the catalyst were investigated. The results showed that the catalyst prepared with a metal nickel content of 0.2 mmol using 100 mg of the nano-TiO2 support had the best catalytic performance. Hydrazine hydrate could be completely decomposed at 343 K in 2.83 min, the hydrogen selectivity attained 100%, and the turnover frequency (TOF) value was 265.49 h-1. In this catalyst, transition metal Ni was dispersed on the support surface in the form of amorphous elemental or oxide. Anatase TiO2 support had the advantages of promoting the dispersion of metal Ni, exposing the active site, changing the electronic state of the active center, strengthening the strong metal-support interaction (SMSI), and improving the activity of the catalyst. After ten cycles of use, the performance of the catalyst stabilized and the hydrogen selectivity was still as high as 100%.