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Background China has been using inactivated coronavirus disease 2019 (COVID-19) vaccines as primary series and booster doses to protect the population from severe to fatal COVID-19. We evaluated primary and booster vaccine effectiveness (VE) against Omicron BA.2 infection outcomes. Methods This was a 13-province retrospective cohort study of quarantined close contacts of BA.2-infected individuals. Outcomes were BA.2 infection, COVID-19 pneumonia or worse, and severe/critical COVID-19. Absolute VE was estimated by comparison with an unvaccinated group. Results There were 289 427 close contacts ≥3 years old exposed to Omicron BA.2 cases; 31 831 turned nucleic acid amplification test–positive during quarantine, 97.2% with mild or asymptomatic infection, 2.6% with COVID-19 pneumonia, and 0.15% with severe/critical COVID-19. None died. Adjusted VE (aVE) against any infection was 17% for primary series and 22% when boosted. Primary series aVE in adults >18 years was 66% against COVID-19 pneumonia or worse and 91% against severe/critical COVID-19. Booster dose aVE was 74% against pneumonia or worse, and 93% against severe/critical COVID-19. Conclusions Inactivated COVID-19 vaccines provided modest protection from infection, very good protection against pneumonia, and excellent protection against severe/critical COVID-19. Booster doses are necessary to provide strongest protection.

We found the binding affinities of amide naphthotube to neutral organic molecules in water are not influenced by most of small biomolecules, inorganic salts, and PBS and Tris buffers but are reduced in HEPES buffer through competitive binding. Nevertheless, salts do change the binding affinities of amide naphthotube to charged molecules through a screening effect.

Molecular recognition and spectral tuning of organic dyes were achieved in water by amide naphthotubes. The association affinity is up to 4.5 × 107 M−1, and great fluorescence enhancement was observed for styryl derivatives.

Stabilizing water-sensitive reaction intermediates is challenging but desirable for guiding reactions to desired products in water. Herein, we report that labile imine and hemiaminal functional groups can be stabilized inside a synthetic container compound, a water-soluble naphthotube. The naphthotube features a primary amine group anchored in a cavity with both hydrogen bonding sites and hydrophobic surfaces. Aldehydes in bulk aqueous solution are trapped in the cavity by the amine to form hemiaminals stabilized through hydrogen bonding and hydrophobic effects. Dehydration of the hemiaminal to the imine is favored by the release of water from the hydrophobic microenvironment. Both the hemiaminals and imines can be detected at room temperature by NMR spectroscopy and mass spectrometry.

Molecular recognition in water is the basis of numerous biological functions. The key for efficient and selective recognition of an organic drug molecule is to bind both its polar and nonpolar grou...

During the last half a century, great achievements have been made in molecular recognition in parallel with the invention of numerous synthetic receptors. However, the selective recognition of hydrophilic molecules in water remains a generally accepted challenge in supramolecular chemistry but is commonplace in nature. In an earlier Communication [ Huang et al. J. Am. Chem. Soc. 2016 , 138 , 14550 ], we reported a pair of endo-functionalized molecular tubes that surprisingly prefer highly hydrophilic molecules over hydrophobic molecules of a similar size and shape. The hydrophobic effect and hydrogen bonding were proposed to be responsible, but their exact roles were not fully elucidated. In this Article, we present a thorough study on the binding behavior of these molecular tubes toward 44 hydrophilic molecules in water. Principal component analysis reveals that the binding strength is weakly correlated to the hydrophobicity, volume, surface area, and dipole moment of guests. Furthermore, molecular dynamics simulations show the hydrophobic effect through releasing the poorly hydrogen-bonded cavity water contributes to the binding of all the hydrophilic molecules, while hydrogen bonding differentiates these molecules and is thus the key to achieve a high selectivity toward certain hydrophilic molecules over other molecules with a similar size and shape. Therefore, a good guest for these molecular tubes should meet the following criteria: the hydrogen-bonding sites should be complementary, and the molecular volume should be large enough to expel all the cavity water but not too large to cause steric hindrance. This rule of thumb may also be used to design a selective receptor for certain hydrophilic molecules. Following these guidelines, a "best-fit" guest was found for the syn-configured molecular tube with a binding constant as high as 10

The microstructure and electrical properties of ZnO-Bi2O3-based varistor ceramics prepared by the high-energy ball milling were studied. The varistor ceramics samples were characterized by XRD and SEM analysis, as well as by dc electrical measurements, such as the nonlinearity coefficients, leakage current and threshold voltage. The best electrical characteristics were found in sample by the high-energy ball milling 1 h and sintered at 1000 °C for 2 h, which exhibited the threshold voltage was 457 V/mm, the nonlinear coefficient was 59.3 and the leakage current was 1.18 μA.