Self-assembling subnanometer pores with unusual mass-transport properties

A long-standing aim in molecular self-assembly is the development of synthetic nanopores capable of mimicking the mass-transport characteristics of biological channels and pores. Here we report a strategy for enforcing the nanotubular assembly of rigid macrocycles in both the solid state and solution based on the interplay of multiple hydrogen-bonding and aromatic π − π stacking interactions. The resultant nanotubes have modifiable surfaces and inner pores of a uniform diameter defined by the constituent macrocycles. The self-assembling hydrophobic nanopores can mediate not only highly selective transmembrane ion transport, unprecedented for a synthetic nanopore, but also highly efficient transmembrane water permeability. These results establish a solid foundation for developing synthetically accessible, robust nanostructured systems with broad applications such as reconstituted mimicry of defined functions solely achieved by biological nanostructures, molecular sensing, and the fabrication of porous materials required for water purification and molecular separations

Clinical characteristics of 199 discharged patients with COVID-19 in Fujian Province: A multicenter retrospective study between January 22nd and February 27th, 2020.

BackgroundCoronavirus disease 2019 (COVID-19) has quickly spread throughout the country and the world since first broke out in Wuhan, China. The outbreak that started from January 22, 2020, in Fujian Province has been controlled as the number of indigenous cases has not increased since March. We aimed to describe the clinical characteristics of patients with COVID-19 in Fujian Province, China.MethodsIn this retrospective, multicenter study, we collected and analyzed the epidemiological, clinical, and laboratory data of all cases confirmed by nucleic acid tests in five designated hospitals in Fujian Province between January 22 and February 27, 2020. All patients were followed up until discharge. COVID-19 severity was classified as mild, moderate, severe, or critical.ResultsOf 199 discharged patients with COVID-19, 105 patients were male, with a median age of 46.3 years, and 17 patients were severe, and 5 patients were critical on admission. Hypertension and diabetes were the most common comorbidities. The symptoms at illness onset were mainly fever (76.4%), cough (60.8%), and myalgia or fatigue (27.6%). A total of 96.5% of patients had abnormal imaging findings on chest computed tomography. Lymphopenia (37.2%) and hypoxemia (13.6%) were observed. Acute respiratory distress syndrome and respiratory failure occurred in 9 patients (4.5%) and 8 patients (4.0%) respectively. One patient died and the others were cured and discharged with the median hospital stay of 19 days. Old age was negatively correlated with lymphocyte count (r = - 0.296, p ConclusionsPatients in Fujian Province were mostly nonsevere cases with mild or moderate symptoms, and had a lower mortality than patients in Wuhan (4.3%-15%). Older age, hypertension, diabetes, and lymphopenia were risk factors for severity of COVID-19

Self-assembling subnanometer pores with unusual mass-transport properties

A long-standing aim in molecular self-assembly is the development of synthetic nanopores capable of mimicking the mass-transport characteristics of biological channels and pores. Here we report a strategy for enforcing the nanotubular assembly of rigid macrocycles in both the solid state and solution based on the interplay of multiple hydrogen-bonding and aromatic π − π stacking interactions. The resultant nanotubes have modifiable surfaces and inner pores of a uniform diameter defined by the constituent macrocycles. The self-assembling hydrophobic nanopores can mediate not only highly selective transmembrane ion transport, unprecedented for a synthetic nanopore, but also highly efficient transmembrane water permeability. These results establish a solid foundation for developing synthetically accessible, robust nanostructured systems with broad applications such as reconstituted mimicry of defined functions solely achieved by biological nanostructures, molecular sensing, and the fabrication of porous materials required for water purification and molecular separations

Enforced Tubular Assembly of Electronically Different Hexakis(<i>m</i>‑Phenylene Ethynylene) Macrocycles: Persistent Columnar Stacking Driven by Multiple Hydrogen-Bonding Interactions

Hexakis­(<i>m</i>-phenylene ethynylene) (<i>m</i>-PE) macrocycles <b>1</b>–<b>4</b>, sharing the same hydrogen-bonding side chains but having backbones of different electronic properties, are designed to probe the effectiveness of multiple H-bonding interactions in enforcing columnar assemblies. ¹H NMR, absorption, fluorescence, and circular dichroism (CD) spectroscopy indicate that, compared with analogous macrocycles that self-associate based on aromatic stacking which is highly sensitive to the electronic nature of the macrocyclic backbones, macrocycles <b>1</b>–<b>4</b> all exhibit strong aggregation down to the micromolar (μM) concentrations in nonpolar solvents. Increasing solvent polarity quickly weakens aggregation. In THF and DMF, the macrocycles exist as free molecules. The observed solvent effects, along with the behavior of <b>5-F</b>_<b>6</b> that cannot self-associate via H-bonding, confirm that H-bonding plays the dominating role in driving the self-association of <b>1</b>–<b>4</b>. The backbone electronic nature does not change the self-assembling pattern common to <b>1</b>–<b>4</b>. Fluorescence and CD spectra confirm that macrocycles <b>1</b>–<b>4</b> assemble anisotropically, forming helical stacks in which adjacent molecules undergo relative rotation to place individual benzene residues in the favorable offset fashion. Columnar alignment of <b>1</b>–<b>4</b> is confirmed by atomic force microscopy (AFM), which resolves single tubes consisting of stacked macrocycles. In addition, macrocycles with backbones of different electronic properties are found to undergo heteroassociation, forming hybrid nanotubes. This study has demonstrated the generality of enforcing the alignment of shape-persistent macrocycles, which represents an invaluable addition to the small number of known tubular stacks capable of accommodating structurally varied molecular components and provides self-assembling nanotubes with inner pores allowing ready structural and functional modification