Poor durability of the neutralizing response against XBB sublineages after a bivalent mRNA COVID-19 booster dose in persons with HIV.

We estimated the dynamics of the neutralizing response against XBB sublineages and T cell response in persons with HIV (PWH) with previous AIDS and/or CD4 < 200/mm3 receiving the bivalent original strain/BA.4-5 booster dose in fall 2022. Samples were collected before the shot (Day 0), 15 days, 3, and 6 months after. PWH were stratified by immunization status: hybrid immunity (HI; vaccination plus COVID-19) versus nonhybrid immunity (nHI; vaccination only). Fifteen days after the booster, 16% and 30% of PWH were nonresponders in terms of anti-XBB.1.16 or anti-EG.5.1 nAbs, respectively. Three months after, a significant waning of anti-XBB.1.16, EG.5.1 and -XBB.1 nAbs was observed both in HI and nHI but nAbs in HI were higher than in nHI. Six months after both HI and nHI individuals displayed low mean levels of anti-XBB.1.16 and EG.5.1 nAbs. Regarding T cell response, IFN-γ values were stable over time and similar in HI and nHI. Our data showed that in PWH, during the prevalent circulation of the XBB.1.16, EG.5.1, and other XBB sublineages, a mRNA bivalent vaccine might not confer broad protection against them. With a view to the 2023/2024 vaccination campaign, the use of the monovalent XBB.1.5 mRNA vaccine should be urgently warranted in PWH to provide adequate protection.

Unexpected Electronic Features of NiO Quantum Dots Produced by Femtosecond Pulsed Laser Ablation in Water.

This study examines the effect of quantum confinement and surface orientations on the electronic properties of NiO quantum dots. It compares NiO nanocrystals produced via atmospheric-pressure microplasma and femtosecond laser (fs-laser) ablation in water, finding that both methods yield quantum-confined nanocrystals with a defined face-centered cubic lattice. Notably, fs-laser synthesis generates crystalline nanocrystals from both crystalline and amorphous targets. While the electronic properties, i.e., energy of the highest occupied molecular orbital and lowest unoccupied molecular orbital (LUMO), of microplasma-synthesized NiO nanocrystals are consistent with the literature, the electronic characteristics of NiO nanocrystals produced by a fs-laser, particularly the high-lying LUMO level, are unusual for NiO quantum dots. Supported by density functional theory calculations, we show that the observed level positions are related to the different polar and nonpolar faces of the nanocrystal surface.

Flexible Bifunctional Electrode for Alkaline Water Splitting with Long-Term Stability.

Progress in electrochemical water-splitting devices as future renewable and clean energy systems requires the development of electrodes composed of efficient and earth-abundant bifunctional electrocatalysts. This study reveals a novel flexible and bifunctional electrode (NiO@CNTR) by hybridizing macroscopically assembled carbon nanotube ribbons (CNTRs) and atmospheric plasma-synthesized NiO quantum dots (QDs) with varied loadings to demonstrate bifunctional electrocatalytic activity for stable and efficient overall water-splitting (OWS) applications. Comparative studies on the effect of different electrolytes, e.g., acid and alkaline, reveal a strong preference for alkaline electrolytes for the developed NiO@CNTR electrode, suggesting its bifunctionality for both HER and OER activities. Our proposed NiO@CNTR electrode demonstrates significantly enhanced overall catalytic performance in a two-electrode alkaline electrolyzer cell configuration by assembling the same electrode materials as both the anode and the cathode, with a remarkable long-standing stability retaining ∼100% of the initial current after a 100 h long OWS run, which is attributed to the "synergistic coupling" between NiO QD catalysts and the CNTR matrix. Interestingly, the developed electrode exhibits a cell potential (E10) of only 1.81 V with significantly low NiO QD loading (83 µg/cm2) compared to other catalyst loading values reported in the literature. This study demonstrates a potential class of carbon-based electrodes with single-metal-based bifunctional catalysts that opens up a cost-effective and large-scale pathway for further development of catalysts and their loading engineering suitable for alkaline-based OWS applications and green hydrogen generation.

Effect of chemical and physical agents on monkeypox virus infectivity and downstream research applications.

The 2022 global spread of Monkeypox Virus (MPXV) underlined the need to investigate safe-handling procedures of clinical and research samples. Here we evaluated the efficiency in reducing MPXV infectious titer of Triton X-100 (0.1 and 0.2%), UV-C irradiation (15 or 30 min), and heat (56 °C 30 min or 70 °C 5 min). The treatment of MPXV at 70 °C resulted in the strongest decrease of MPXV infectious titer (5.4 Log TCID50/mL), 56 °C and UV-C had a lighter impact (3.9 and 4.3Log), Triton X-100 was less efficient (1.8-2.5Log). Notably, SARS-CoV-2 was much more susceptible to Triton X-100 (4.0 Log decrease). UV-C had the highest impact on MPXV DNA detection by PCR (2.2-4.3 Ct value increase); protein detection by ELISA was dramatically impaired by heating. Overall, UV-C and heating were more effective in lowering MPXV infectious titer but their impact on nucleic acids or protein detection assays must be considered.

Dielectric Barrier Plasma Discharge Exsolution of Nanoparticles at Room Temperature and Atmospheric Pressure.

Exsolution of metal nanoparticles (NPs) on perovskite oxides has been demonstrated as a reliable strategy for producing catalyst-support systems. Conventional exsolution requires high temperatures for long periods of time, limiting the selection of support materials. Plasma direct exsolution is reported at room temperature and atmospheric pressure of Ni NPs from a model A-site deficient perovskite oxide (La0.43Ca0.37Ni0.06Ti0.94O2.955). Plasma exsolution is carried out within minutes (up to 15 min) using a dielectric barrier discharge configuration both with He-only gas as well as with He/H2 gas mixtures, yielding small NPs (<30 nm diameter). To prove the practical utility of exsolved NPs, various experiments aimed at assessing their catalytic performance for methanation from synthesis gas, CO, and CH4 oxidation are carried out. Low-temperature and atmospheric pressure plasma exsolution are successfully demonstrated and suggest that this approach could contribute to the practical deployment of exsolution-based stable catalyst systems.

Real World Use of Tixagevimab/Cilgavimab Pre-Exposure Prophylaxis of COVID-19 in Immunocompromised Individuals: Data from the OCTOPUS Study.

Objective. We aimed to report the real-world use and outcomes over time in immunocompromised individuals receiving tixagevimab/cilgavimab (T/C) pre-exposure prophylaxis (PrEP). Methods. This observational study included participants who received T/C PrEP, categorized into three groups: (i) No COVID-19 (NoC), i.e., participants who never had COVID-19; (ii) Hybrids (H), i.e., participants who had COVID-19 before PrEP; and (iii) Break-through Infections (BTIs), i.e., participants who had COVID-19 after PrEP. The study measured several immune markers at the administration of T/C (T0) at 3 (T1), 6 (T2), and 9 (T3) months afterward. These markers included: anti-receptor-binding domain (RBD) IgG antibodies; BA.5-neutralizing antibodies (nAbs); mucosal IgG; and T cell immunity. The incidence rate ratios for BTIs were analyzed using a Poisson regression model. Results. A total of 231 participants with a median age of 63 years (IQR 54.0-73.0). were included. Among these, 84% had hematological diseases and received a median of three vaccine doses. N = 72 participants belonged to the NoC group, N = 103 to the H group, and n = 56 to the BTI group (24%), with most BTIs being mild/moderate. The incidence rate (IR) of BTIs was 4.2 per 100 patient-months (95% CI 3.2-5.4), with no associated risk factors identified. There was a significant increase in anti-RBD IgG levels 3 months after the T/C administration in all groups, followed by a decline at 6 months, whereas at the same time points, geometric mean titers (GMTs) of anti-BA.5 nAbs were low for all groups and were around or below the detection threshold. No significant changes were observed in IFN-γ levels. The mucosal immune response was observed only 3 months after the PrEP administration. Conclusion. We provided a real-world experience model on the clinical efficacy of T/C PrEP in preventing severe COVID-19 during the Omicron wave through a comprehensive virological and immunological study. While waiting for the arrival of new monoclonal antibodies that can effectively neutralize the most recent variants, T/C PrEP remains the only viable strategy in the available armamentarium today to prevent COVID-19 complications in an extremely fragile population with suboptimal immune responses to COVID-19 vaccines.

Long Term Assessment of Anti-SARS-CoV-2 Immunogenicity after mRNA Vaccine in Persons Living with HIV.

(1) Background: Waning of neutralizing and cell-mediated immune response after the primary vaccine cycle (PVC) and the first booster dose (BD) is of concern, especially for PLWH with a CD4 count ≤200 cells/mm3. (2) Methods: Neutralizing antibodies (nAbs) titers by microneutralization assay against WD614G/Omicron BA.1 and IFNγ production by ELISA assay were measured in samples of PLWH at four time points [2 and 4 months post-PVC (T1 and T2), 2 weeks and 5 months after the BD (T3 and T4)]. Participants were stratified by CD4 count after PVC (LCD4, ≤200/mm3; ICD4, 201-500/mm3, and HCD4, >500/mm3). Mixed models were used to compare mean responses over T1-T4 across CD4 groups. (3) Results: 314 PLWH on ART (LCD4 = 56; ICD4 = 120; HCD4 = 138) were enrolled. At T2, levels of nAbs were significantly lower in LCD4 vs. ICD4/HCD4 (p = 0.04). The BD was crucial for increasing nAbs titers above 1:40 at T3 and up to T4 for WD614G. A positive T cell response after PVC was observed in all groups, regardless of CD4 (p = 0.31). (4) Conclusions: Waning of nAbs after PVC was more important in LCD4 group. The BD managed to re-establish higher levels of nAbs against WD614G, which were retained for 5 months, but for shorter time for Omicron BA.1. The T cellular response in the LCD4 group was lower than that seen in participants with higher CD4 count, but, importantly, it remained above detectable levels over the entire study period.