Herd immunity through vaccination is a key measure to control COVID-19 pandemic. However, vaccine hesitancy remains a public health threat, which is still common among healthcare workers (HCWs). This systematic review aimed to synthesise evidence on HCWs’ attitudes towards COVID-19 vaccination and analyse associated factors to provide information for vaccine policy development and practice. We searched PubMed, Embase, ScienceDirect, Web of Science and three Chinese databases for literature published on 12 February 2021. Two researchers screened the literature independently, and 13 studies were included in the systematic review. Vaccine acceptance varied widely and ranged from 27.7% to 77.3%. HCWs had positive attitudes towards future COVID-19 vaccines, while vaccine hesitancy was still common. Demographic variables such as men, older age and physicians were positive predictive factors. Women and nurses had more vaccine hesitancy. Previous influenza vaccination and self-perceived risk were facilitators. Concerns for safety, efficacy and effectiveness and distrust of the government were barriers. Influences of direct (COVID-19) patient care towards vaccination intention were less conclusive. Tailored communication strategies were needed to increase the uptake rate of COVID-19 vaccines among HCWs. More importantly, more data and information on the safety and efficacy of vaccines should be provided with transparency.

We present a new approach to carry out non-adiabatic molecular dynamics to study the carrier mobility in an organic monolayer. This approach allows the calculation of a 4802 atom system for 825 fs in about three hours using 51,744 computer cores while maintaining a plane wave pseudopotential density functional theory level accuracy for the Hamiltonian. Our simulation on a pentathiophene butyric acid monolayer reveals a previously unknown new mechanism for the carrier transport in such systems: the hole wave functions are localized by thermo fluctuation induced disorder, while its transport is via charge transfer during state energy crossing. The simulation also shows that the system is not in thermo dynamic equilibrium in terms of adiabatic state populations according to Boltzmann distribution. Our simulation is achieved by introducing a linear time dependence approximation of the Hamiltonian within a fs time interval, and by using the charge patching method to yield the Hamiltonian, and overlapping fragment method to diagonalize the Hamiltonian matrix.

There is a small, but growing, body of literature describing the use of osmotic coefficient measurements to validate and reparameterize simulation force fields. Here we have investigated the ability of five very commonly used force field and water model combinations to reproduce the osmotic coefficients of seven neutral amino acids and five small molecules. The force fields tested include AMBER ff99SB-ILDN, CHARMM36, GROMOS54a7, and OPLS-AA, with the first of these tested in conjunction with the TIP3P and TIP4P-Ew water models. In general, for both the amino acids and the small molecules, the tested force fields produce computed osmotic coefficients that are lower than experiment; this is indicative of excessively favorable solute-solute interactions. The sole exception to this general trend is provided by GROMOS54a7 when applied to amino acids: in this case, the computed osmotic coefficients are consistently too high. Importantly, we show that all of the force fields tested can be made to accurately reproduce the experimental osmotic coefficients of the amino acids when minor modifications – some previously reported by others and some that are new to this study – are made to the van der Waals interactions of the charged terminal groups. Special care is required, however, when simulating Proline with a number of the force fields, and a hydroxyl-group specific modification is required in order to correct Serine and Threonine when simulated with AMBER ff99SB-ILDN. Interestingly, an alternative parameterization of the van der Waals interactions in the latter force field, proposed by the Nerenberg and Head-Gordon groups, is shown to immediately produce osmotic coefficients that are in excellent agreement with experiment. Overall, this study reinforces the idea that osmotic coefficient measurements can be used to identify general shortcomings in commonly used force fields’ descriptions of solute-solute interactions, and further demonstrates that modifications to van der Waals parameters provides a simple route to optimizing agreement with experiment.