SARS-CoV-2 vaccines in China could reduce COVID-19-related respiratory syndromes and deaths: A retrospective cohort study.

Background: Information is limited regarding the effectiveness of the inactivated vaccine for COVID-19 approved in China in preventing infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) when administered in real-world conditions. Methods: We retrospectively surveyed 1352 patients with a positive SARS-CoV-2 nucleic acid test treated at a major tertiary medical center in Foshan city (Guangdong, China) between November 2022 and February 2023. The exposure group was patients who had previously received the COVID-19 vaccine, which included patients who had received different doses of the vaccine and different vaccine types. The primary outcome of this study was the effectiveness of the vaccine in preventing severe disease and death among SARS-CoV-2-infected patients. Results: We found a mortality rate of 12.1 % associated with COVID-19. The results showed that an increase in the number of vaccine doses was associated with a reduction in in-hospital mortality. When compared to unvaccinated patients, vaccinated patients had an 8.5 % lower mortality rate. There was also a statistically significant reduction in the risk of death among vaccinated patients compared to unvaccinated patients (OR = 0.521 [95 % CI, 0.366 to 0.741]). Patients who had received the vaccine had a 22.8 % reduction in the risk of severe disease. In addition, the use of antiviral drugs decreased progressively with increasing vaccine doses (P < 0.05). Of these, anticoagulation, Paxlovid, and mechanical ventilation were used least frequently in the one-dose group. Conclusions: The vaccines approved in China mitigated the incidence of severe COVID-19 and reduced mortality. These findings suggest that COVID-19 vaccination can help to control the pandemic.

Constructing the quinonyl groups and structural defects in carbon for supercapacitor and capacitive deionization applications.

The structural defects and oxygen-containing functional groups of carbon materials as electrode materials for supercapacitors or capacitive deionization devices are critical to their electrochemical performance. The tuning of surface oxygen-containing functional groups and carbon defects during pyrolysis is key to achieve a high performance in ion storage. Herein, quinonyl-dominant defective porous carbon is prepared by a pyrolysis and cross-linking route using lavender stem and potassium acetate as precursor. Benefiting from the presence of abundant defect and surface quinonyl groups, porous carbon shows an ultra-high specific capacitance of 401 F g-1 (1 A g-1) and a high capacitance retention of 63% at a high current density of 100 A g-1 in a KOH solution. Meanwhile, as a capacitive deionization electrode material, it also exhibited a high adsorption capacity of 25.5 mg g-1 in 500 mg L-1 NaCl solution at 1.2 V. Theoretical density functional theory (DFT) calculation demonstrates that surface quinonyl groups and carbon defects can synergistically facilitate the adsorption of K+ and Na+ during the charge/discharge process. This work provides a new perspective for understanding the role of surface oxygen-containing groups and intrinsic defects of porous carbon materials in electrochemical energy storage and desalination applications.

Hybrid nanoarchitectonics of coal-derived carbon with oxidation-induced morphology-selectivity for high-performance supercapacitor.

Coal-derived porous carbon with a large specific surface area is a common electrode material for supercapacitors. Its deep and branched micropores, dense bulk morphology and amorphous structure have greatly limited its practical applications. Herein, hybrid carbon materials were obtained from coal through oxidation followed by activation. The method allows tuning the morphology, porosity, structure, and the degree of graphitization. The pre-oxidation with KMnO4 can break raw coal into small hydrocarbon fragments, which deposit and grow on the surface of generated MnO during pyrolysis leading to hybrid carbon with mesoporous and graphitic nanostructures. Meanwhile, homogeneous etching of the carbon skeleton by the reaction intermediate of K2CO3 led to the formation of abundant active sites. Hence, the optimized sample exhibited a high capacitance of 333 F g-1 at 1 A g-1, an excellent rate capability with 58% capacitance retention at 100 A g-1 and superior cycle durability in a three-electrode system. Besides, an assembled symmetric two-electrode device displayed a high energy density of 8.9 Wh·kg-1 at 250 W·kg-1. This work proposed a facile and rational synthesis strategy by balancing the tradeoff between active sites and intrinsic conductivity and thus provided a new avenue for the value-added utilization of coal.

Homogeneous activation induced by bacterial cellulose nanofibers to construct interconnected microporous carbons for enhanced capacitive storage.

Porous carbons have been widely applied for capacitive energy storage, yet usually suffer from insufficient rate performance because of the sluggish ion transport kinetics in deep and multi-branched pores. Herein, we fabricated an interconnected microporous capacitive carbon (IMCC) by growing D (+)-glucosamine on bacterial cellulose (BC) nanofibers scaffold, followed by carbonization and activation. The BC nanofibers acted as a sacrificial template during pre-carbonization, facilitating the subsequent KOH permeation and homogeneous activation. By taking advantage of the interconnected microporous structure, the IMCC delivers a high capacitance of 302 F g-1 at 1 A g-1 and an excellent rate capability of 165 F g-1 at 100 A g-1 for aqueous supercapacitor, demonstrating its fast ion transport capability. Impressively, it also shows a superior gravimetric capacity of 177 mAh g-1 at 0.5 A g-1 and remains a high value of 72 mAh g-1 at 20 A g-1 as a cathode material for Zn-ion hybrid capacitor. This facile and cost-effective design strategy exhibits a great potential to construct carbohydrates-derived interconnected microporous carbon materials for high-rate energy storage.

Improving the surface area of metal organic framework-derived porous carbon through constructing inner support by compatible graphene quantum dots.

Metal-organic frameworks (MOFs) have emerged as promising precursors to prepare porous carbons due to their unique coordination structure with abundant pores and various chemical compositions. However, the structural collapse and pore shrinkage during pyrolysis severely decrease the surface area of the prepared porous carbons. Herein, we propose an inner support strategy to prepare MOF-derived carbons with improved surface area using graphene quantum dots (GQDs) as the compatible frameworks. GQDs with abundant carboxyl groups (-COOH) and rigid structure can uniformly distribute in MOF-5 precursor by coordinating with [Zn4O]6+ clusters and effectively reinforce the carbon skeleton during pyrolysis. Therefore, the rational GQDs embedded MOF-5 derived porous carbon (GMPC-0.35) shows greatly improved specific surface area (1841 m2 g-1) and mesopore volume (1.62 cm3 g-1) than pure MOF-5 derived carbon (1358 m2 g-1, 0.59 cm3 g-1). As an application exemplification, GMPC-0.35 performs high specific capacitance of 200 F g-1 at 1 A g-1 and good capacitance retention of 53% at 100 A g-1 as the electrode material for supercapacitors, which are higher than most of the reported MOF-5 derived carbons. Therefore, the compatible GQDs support is promising for preparing functional MOF-derived carbon materials.

Enabling a Large Accessible Surface Area of a Pore-Designed Hydrophilic Carbon Nanofiber Fabric for Ultrahigh Capacitive Deionization.

Although porous carbons have been widely used for capacitive deionization, the low accessible surface area because of the hydrophobic microporous structure results in unsatisfied desalination capacity, which drastically hinders their practical application. Herein, a novel carbon nanofiber fabric with a large accessible surface area was prepared by electrospinning using the uniformly dispersed ferrocene as a pore former. The carbon nanofiber fabric with good mechanical strength and flexibility can be directly used as a filter membrane to filter simulated sandy seawater. The high content of heteroatoms increases the surface polarity of the carbon nanofiber, while the well-controlled interconnected mesoporous structure of the optimized sample facilitates fast transport and adsorption of hydrated Na+ and Cl-. Thus, the hydrophilic carbon nanofiber fabric shows a Brunauer-Emmett-Teller surface area of 922 m2 g-1 and a large accessible surface area of 405 m2 g-1, leading to a high capacitance of 263 F g-1 in the NaCl electrolyte. Most importantly, it shows an ultrahigh desalination capacity of 19.34 mg g-1, which is much higher than most of the previously reported carbon materials. The high desalination capacity, fast adsorption rate, and good cycle stability make the as-prepared carbon nanofiber fabric an attractive candidate for practical application.