IMPORTANCE A surge of COVID-19 occurred from March to June 2021, in New Delhi, India, linked to the B.1.617.2 (Delta) variant of SARS-CoV-2. COVID-19 vaccines were rolled out for health care workers (HCWs) starting in January 2021. OBJECTIVE To assess the incidence density of reinfection among a cohort of HCWs and estimate the effectiveness of the inactivated whole virion vaccine BBV152 against reinfection. DESIGN, SETTING, AND PARTICIPANTS This was a retrospective cohort study among HCWs working at a tertiary care center in New Delhi, India.EXPOSURES Vaccination with 0, 1, or 2 doses of BBV152. MAIN OUTCOMES AND MEASURESThe HCWs were categorized as fully vaccinated (with 2 doses and Ն15 days after the second dose), partially vaccinated (with 1 dose or 2 doses with <15 days after the second dose), or unvaccinated. The incidence density of COVID-19 reinfection per 100 personyears was computed, and events from March 3, 2020, to June 18, 2021, were included for analysis.Unadjusted and adjusted hazard ratios (HRs) were estimated using a Cox proportional hazards model. Estimated vaccine effectiveness (1 − adjusted HR) was reported. RESULTS Among 15 244 HCWs who participated in the study, 4978 (32.7%) were diagnosed with COVID-19. The mean (SD) age was 36.6 (10.3) years, and 55.0% were male. The reinfection incidence density was 7.26 (95% CI: 6.09-8.66) per 100 person-years (124 HCWs [2.5%], total person follow-up period of 1696 person-years as time at risk). Fully vaccinated HCWs had lower risk of reinfection (HR, 0.14 [95% CI, 0.08-0.23]), symptomatic reinfection (HR, 0.13 [95% CI, 0.07-0.24]), and asymptomatic reinfection (HR, 0.16 [95% CI, 0.05-0.53]) compared with unvaccinated HCWs.Accordingly, among the 3 vaccine categories, reinfection was observed in 60 of 472 (12.7%) of unvaccinated (incidence density, 18.05 per 100 person-years; 95% CI, 14.02-23.25), 39 of 356 (11.0%) of partially vaccinated (incidence density 15.62 per 100 person-years; 95% CI,, and 17 of 1089 (1.6%) fully vaccinated (incidence density 2.18 per 100 person-years; 95% CI, 1.35-3.51) HCWs. The estimated effectiveness of BBV152 against reinfection was 86% (95% CI, 77%-92%); symptomatic reinfection, 87% (95% CI, 76%-93%); and asymptomatic reinfection, 84% (95% CI, 47%-95%) among fully vaccinated HCWs. Partial vaccination was not associated with reduced risk of reinfection. (continued) Key Points Question What are the rate of reinfection of SARS-CoV-2 among a cohort of health care workers (HCWs) and the estimated effectiveness of the inactivated whole virion vaccine BBV152 against reinfection? Findings In this cohort study of 4978 HCWs who were infected with SARS-CoV-2 from March 3, 2020, to June 18, 2021, the incidence density of reinfection was 7.26 per 100 personyears. A protective association of 86% against reinfection was observed among HCWs who completed the 2-dose schedule of BBV152 and for whom at least 15 days elapsed without reinfection after vaccination. Meaning The results of this study suggest that complete vaccination with BBV152 amo...

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Emulsification of immiscible two-phase fluids, i.e., one condensed phase dispersed homogeneously as tiny droplets in an outer continuous medium, plays a key role in medicine, food, chemical separations, cosmetics, fabrication of micro- and nanoparticles and capsules, and dynamic optics. Herein, we demonstrate that water clusters/droplets can be formed in an organic phase via the spontaneous assembling of ionic bilayers. We term these clusters ionosomes, by analogy with liposomes where water clusters are encapsulated in a bilayer of lipid molecules. The driving force for the generation of ionosomes is a unique asymmetrical electrostatic attraction at the water/oil interface: small and more mobile hydrated ions reside in the inner aqueous side, which correlate tightly with the lipophilic bulky counterions in the adjacent outer oil side. These ionosomes can be formed through electrochemical (using an external power source) or chemical (by salt distribution) polarization at the liquid–liquid interface. The charge density of the cations, the organic solvent, and the synergistic effects between tetraethylammonium and lithium cations, all affecting the formation of ionosomes, were investigated. These results clearly prove that a new emulsification strategy is developed providing an alternative and generic platform, besides the canonical emulsification procedure with either ionic or nonionic surfactants as emulsifiers. Finally, we also demonstrate the detection of individual ionosomes via single-entity electrochemistry.

Highly ordered mesoporous C with a well-ordered porous structure and a high crystallinity is prepared through the nanohard templating method using a saturated solution of C in 1-chloronaphthalene (51 mg mL ) as a C precursor and SBA-15 as a hard template. The high solubility of C in 1-chloronaphthalene helps not only to encapsulate a huge amount of the C into the mesopores of the template but also supports the oligomerization of C and the formation of crystalline walls made of C . The obtained mesoporous C exhibits a rod-shaped morphology, a high specific surface area (680 m g ), tuneable pores, and a highly crystalline wall structure. This exciting ordered mesoporous C offers high supercapacitive performance and a high selectivity to H O production and methanol tolerance for ORR. This simple strategy could be adopted to make a series of mesoporous fullerenes with different structures and carbon atoms as a new class of energy materials.

The layered ternary chalcogenide, palladium phosphorous sulphide (PdPS), and its composite with reduced graphene oxide are shown to be efficient hydrogen evolution electrocatalysts. The Tafel slope and the exchange current density values associated with hydrogen evolution reaction are determined to be 46 mV dec(-1) and 1.4 × 10(-4) A cm(-2) respectively.