SARS-CoV-2 Infection, Inflammation, Immunonutrition, and Pathogenesis of COVID-19.

The COVID-19 pandemic, caused by the coronavirus, SARS-CoV-2, has claimed millions of lives worldwide in the past two years. Fatalities among the elderly with underlying cardiovascular disease, lung disease, and diabetes have particularly been high. A bibliometrics analysis on author's keywords was carried out, and searched for possible links between various coronavirus studies over the past 50 years, and integrated them. We found keywords like immune system, immunity, nutrition, malnutrition, micronutrients, exercise, inflammation, and hyperinflammation were highly related to each other. Based on these findings, we hypothesized that the human immune system is a multilevel super complex system, which employs multiple strategies to contain microorganism infections and restore homeostasis. It was also found that the behavior of the immune system is not able to be described by a single immunological theory. However, one main strategy is "self-destroy and rebuild", which consists of a series of inflammatory responses: 1) active self-destruction of damaged/dysfunctional somatic cells; 2) removal of debris and cells; 3) rebuilding tissues. Thus, invading microorganisms' clearance could be only a passive bystander response to this destroy-rebuild process. Microbial infections could be self-limiting and promoted as an indispensable essential nutrition for the vast number of genes existing in the microorganisms. The transient nutrition surge resulting from the degradation of the self-destroyed cell debris coupled with the existing nutrition state in the patient may play an important role in the pathogenesis of COVID-19. Finally, a few possible coping strategies to mitigate COVID-19, including vaccination, are discussed.

Nutrition acquisition by human immunity, transient overnutrition and the cytokine storm in severe cases of COVID-19.

The human immunity has a pivotal role in nutrition acquisition from the pathogens and damaged body tissue during the SARS-CoV-2 virus infection, which may lead to transient overnutrition in the patients, lead to lipotoxicity and further damage in non-adipose tissues, and cause hyperinflammation and cytokine storm in severe cases of COVID-19. In view of this, high-quality clinical trials on restrictive eating should be designed to investigate the possible benefits of food intake restriction on patients' recovery from COVID-19 disease.

Commentary: Reconciling Hygiene and Cleanliness: A New Perspective from Human Microbiome.

Human beings have co-evolved with the microorganisms in our environment for millions of years, and have developed into a symbiosis in a mutually beneficial/defensive way. Human beings have significant multifaceted relationships with the diverse microbial community. Apart from the important protective role of microbial community exposure in development of early immunity, millions of inimitable bacterial genes of the diverse microbial community are the indispensable source of essential nutrients like essential amino acids and essential fatty acids for human body. The essential nutrition from microbiome is harvested through xenophagy. As an immune effector, xenophagy will capture any microorganisms that touch the epithelial cells of our gastrointestinal tract, degrade them and turn them into nutrients for the use of our body.

Skeleton Engineering of Homocoupled Conjugated Microporous Polymers for Highly Efficient Uranium Capture via Synergistic Coordination.

Developing efficient adsorbents for uranium enrichment is of great significance for resource sustainability and environmental safety. This study presents a facile and adaptable post-synthetic strategy to prepare highly efficient uranium adsorbents via engineering the π-conjugated skeletons of homocoupled conjugated microporous polymers (HCMPs). Taking advantage of the diyne units in the π-conjugated skeletons, bis-amidoxime uranophiles, one of the state-of-the-art ligands of uranyl ions, were introduced to the frameworks of HCMPs. The functionalized HCMPs preserved the interconnected 3D microporous networks and rigid conjugated skeletons with abundant bis-amidoxime ligands uniformly distributed in the pore channels. Such structural advantages of the adsorbents afforded very fast adsorption kinetics within 15 min to reach the equilibrium and high capacity of uranium (450 mg/g). Moreover, DFT calculation suggests a synergistic coordination as the most energetically favored coordination mode of the uranyl/bis-amidoxime complexes. This study contributes new insights into the underlying mechanism responsible for the highly efficient adsorption ability of the bis-amidoxime-functionalized HCMPs toward uranium. Meanwhile, the synthetic methodology established here could be extended to task-specific design and skeleton engineering of more functional HCMPs for broadened applications.

Membrane-supported 1D MOF hollow superstructure array prepared by polydopamine-regulated contra-diffusion synthesis for uranium entrapment.

This work reports the architecture of a novel class of membrane-supported 1D MOF hollow superstructures, by using the bio-inspired polydopamine (PDA) mediated contra-diffusion synthetic strategy, for facile and efficient separation of uranium in a flow-through mode. PDA chemistry was firstly employed to modify the inner surfaces of the cylindrical pore channels of polycarbonate track-etched membrane (PCTM), thereby regulating the heterogeneous nucleation and interfacial growth of ZIF-8 crystals. ZIF-8 hollow superstructures embedded in membrane matrix with well-defined 1D channels were obtained. These membrane-supported MOF hollow superstructures then, for the first time, served as integrated chromatographic micro-column arrays for effective entrapment of uranium from aqueous solutions. It is highlighted that the PCTM supported ZIF-8 superstructures exhibited outstanding uranium entrapment ability in both traditional batch mode (capacity 62.3 mg/g) and fast flow-through mode (removal rate over 90% for 3 level). Moreover, new insights into the interaction between ZIF-8 and uranyl ions were obtained, suggesting that an ion-exchange mechanism involved synergistic effect was responsible for uranium binding, especially in a long-term exposure. The membrane-supported 1D MOF hollow superstructures developed in this work represent a new category of organic-inorganic composite membrane. And, it is envisioned that the methodology established in this work would be versatile for preparing more MOF superstructures with deployable form for separation applications. In summary, a novel class of membrane-supported ZIF-8 hollow superstructure was fabricated for effective separation of uranyl ions.

N-doped catalytic graphitized hard carbon for high-performance lithium/sodium-ion batteries.

Hard carbon attracts wide attentions as the anode for high-energy rechargeable batteries due to its low cost and high theoretical capacities. However, the intrinsically disordered microstructure gives it poor electrical conductivity and unsatisfactory rate performance. Here we report a facile synthesis of N-doped graphitized hard carbon via a simple carbonization and activation of a urea-soaked self-crosslinked Co-alginate for the high-performance anode of lithium/sodium-ion batteries. Owing to the catalytic graphitization of Co and the introduction of nitrogen-functional groups, the hard carbon shows structural merits of ordered expanded graphitic layers, hierarchical porous channels, and large surface area. Applying in the anode of lithium/sodium-ion batteries, the large surface area and the existence of nitrogen functional groups can improve the specific capacity by surface adsorption and faradic reaction, while the hierarchical porous channels and expanded graphitic layers can provide facilitate pathways for electrolyte and improve the rate performance. In this way, our hard carbon provides its feasibility to serve as an advanced anode material for high-energy rechargeable lithium/sodium-ion batteries.

Polydopamine Induced in-Situ Formation of Metallic Nanoparticles in Confined Microchannels of Porous Membrane as Flexible Catalytic Reactor.

Oxidant-regulated polymerization of dopamine was exploited, for the first time, for effective surface engineering of the well-defined cylindrical pores of nuclear track-etched membranes (NTEMs) to develop novel catalytic membrane reactor. First, in the presence of a strong oxidant, controlled synthesis of polydopamine (PDA) with tunable particle size was achieved, allowing a homogeneous deposition to the confined pore channels of NTEMs. The PDA interfaces rich in catechol and amine groups provided enhanced hydrophilicity to promote mass transport across the membrane and abundant nucleation sites for formation and stabilization of metallic nanoparticles (NPs). In-situ reductive growth of multiple metallic NPs, including Pd, Ag, and Au, was then achieved inside the cylindrical pores of NTEMs. Using the functionalized membrane as a catalytic reactor, efficient reduction of 4-nitrophenol (4-NP) was demonstrated in a flow-through mode. Moreover, after dissolution removal of the NTEMs, self-sustained one-dimensional (1D) PDA/M (M = Pd, Ag, or Au) hybrid nanotubes (NTs), with determined aspect ratio and a length reaching up to 10 µm, were obtained for catalysis of 4-NP in a batch reaction mode. This study established a facile and versatile method, by rational tuning of the polymerization behavior of dopamine, for effective modification of confined microscale/nanoscale cavities with different surface characteristics. The integration of PDA chemistry with NTEMs would provide more opportunities for development of novel catalytic membrane reactors as well as for the tailored synthesis of functional 1D nanotubes for broadened applications.