The nature of pH in a pure water pool that is too small to have a continuous population of ions formed by water dissociation is not settled. Here, we use stochastic kinetics simulations of the water dissociation reaction in pools ranging from 103 to 1016 waters to characterize water ion lifetimes and populations. An availability coefficient is defined to quantify the intermittent presence of ion pairs during an arbitrary observation period and used in a proposed definition for the effective pH of nanoscopic pools. The effective pH converges to the bulk value of 7 for water pools in the range of 1010 waters. The lifetimes of water ion pairs are found to increase with increasing water pool size due to the balance between their formation and recombination kinetics, with a maximum near the size where bulk-like characteristics begin to dominate and ion pairs are continuously present.

Corrosion resistance has become an important factor to consider in integrated computational materials engineering, yet generating science-based indicators of corrosion resistance for hypothetical materials remains challenging. We explore the quantitative relations between work function and corrosion potential, taking a theoretical approach that considers the relation between these thermodynamic and kinetically-determined variables. The work function is a fundamental thermodynamic property of a metallic surface in isolation, whereas the corrosion potential is kinetically determined as the potential at which the rates of anodic and cathodic processes active on the metal surface are equal. The latter quantity is therefore time dependent, as well as dependent on the material, surface preparation, ageing/history and the environment. Reasoning from Mixed Potential Theory, we develop a rationale for the correlation between the corrosion potential and the electronic work function. Two distinct Born-Haber cycles for the anodic dissolution reaction are analyzed to allow calculation of a related quantity, the ionic work function, which embodies the energy of desorption for metal cations from an electrode. The ionic work function is not only highly correlated with, but of similar magnitude to the cation hydration energy. The theoretical analysis provided herein establishes the significance of not only the electronic work function, but also the ionic work function, cation hydration energy, cohesive energy and the ionization potential as co-descriptors for the corrosion resistance of candidate corrosion resistant metal alloys, with the role of the environment to be considered in future work.

Background

Zika virus (ZIKV) infection and ZIKV epidemic have been continuously spreading silently throughout the world and its associated microcephaly and other serious congenital neurological complications poses a significant global threat to public health. Type I interferon response to ZIKV infection in host cells suppresses viral replication by inducing the expression of interferon-stimulated genes (ISGs).

Methods

The study aims to demonstrate the anti-ZIKV mechanism of PARP11. PARP11 knock out and overexpressing A549 cell lines were constructed to evaluate the anti-ZIKV function of PARP11. PARP11^-/-, PARP12^-/- and PARP11^-/-PARP12^-/- HEK293T cell lines were constructed to explain the synergistic effect of PARP11 and PARP12 on NS1 and NS3 protein degradation. Western blotting, immunofluorescence and immunoprecipitation assay were performed to illustrate the interaction between PARP11 and PARP12.

Results

Both mRNA and protein levels of PARP11 were induced in WT but not IFNAR1^-/- cells in response to IFNα or IFNβ stimulation and ZIKV infection. ZIKV replication was suppressed in cells expressed PARP11 but was enhanced in PARP11^-/- cells. PARP11 suppressed ZIKV independently on itself PARP enzyme activity. PARP11 interacted with PARP12 and promoted PARP12-mediated ZIKV NS1 and NS3 protein degradation.

Conclusion

We identified ADP-ribosyltransferase PARP11 as an anti-ZIKV ISG and found that it cooperated with PARP12 to enhance ZIKV NS1 and NS3 protein degradation. Our findings have broadened the understanding of the anti-viral function of ADP-ribosyltransferase family members, and provided potential therapeutic targets against viral ZIKV infection.

Corrosion is an electrochemical phenomenon. It can occur via different modes of attack, each having its own mechanisms, and therefore there are multiple metrics for evaluating corrosion resistance. In corrosion resistant alloys (CRAs), the rate of localized corrosion can exceed that of uniform corrosion by orders of magnitude. Therefore, instead of uniform corrosion rate, more complex electrochemical parameters are required to capture the salient features of corrosion phenomena. Here, we collect a database with an emphasis on metrics related to localized corrosion. The six sections of the database include data on various metal alloys with measurements of (1) pitting potential, E_pit, (2) repassivation potential, E_rp, (3) crevice corrosion potential, E_crev, (4) pitting temperature, T_pit, (5) crevice corrosion temperature, T_crev, and (6) corrosion potential, E_corr, corrosion current density, i_corr, passivation current density, i_pass, and corrosion rate. The experimental data were collected from 85 publications and include Al- and Fe-based alloys, high entropy alloys (HEAs), and a Ni-Cr-Mo ternary system. This dataset could be used in the design of highly corrosion resistant alloys.