Carbon-based cyclic molecules with alternating polycyclic regions and double carbon chains referred to as carbon nanobracelets are studied using spin-polarized density functional theory (DFT) calculations with PBE functional. Optimized structure of considered nanobracelets consisting of 1–5 identical monomers with and without hydrogen atoms at the edge of polycyclic regions is found to have highest possible symmetry and bond length alternation in chains. Nanobracelets consisting of odd number of monomers have lower HOMO energy, greater HOMO-LUMO gap and greater bond length variation in the carbon atomic chains than nanobracelets with even number of monomers.

The paper discusses the development of a multiscale computational model for predicting the permeability of multilayer protective films consisting of multiple polymeric and hybrid layers containing clay minerals as fillers. The presented approach combines three levels of computation: continuous, full atomic, and quantitative structure–property correlations (QSPR). Oxygen and water are chosen as penetrant molecules. The main predictions are made using the continuum model, which takes into account the real scales of films and nanoparticles. It is shown that reliable predictions of the permeability coefficients can be obtained for oxygen molecules, which is not always possible for water. The latter requires the refinement of existing QSPR methods and interatomic interaction potentials for the atomistic level of calculations. Nevertheless, we show that the maximum effect on permeability reduction from the addition of clay fillers to the hybrid layer can be achieved by using nanoparticles with large aspect ratios and a high degree of orientational order. In addition, the use of the hybrid layer should be combined with the use of polymer layers with minimal oxygen and water permeability. The constructed model can be used to improve the properties of protective coatings for food and drug storage and to regulate the gas permeability of polymeric materials.

Abstract Understanding the interaction between small alkane radical ions and methane could lead to more efficient ways of hydrogen production, which is an essential component in the field of green energy. It can contribute to developing new plasma processing methods for natural gas utilization or for its conversion into other useful products. In this study, using first-principles calculations we analyzed interactions between small alkane radical ions and methane molecules, which result in growth of carbon clusters and production of hydrogen in methane plasma. Our observations revealed that anion-methane interactions initiate from C-H bond rupture in CH4, with the lowest activation barrier seen in negative ions undergoing a hydrogen transfer reaction. Positive alkane ion radicals demonstrated a different initial step in the clustering process where CH3 and H transfer reactions occur simultaneously. The total reaction between positive ethyl ion and methane has low activation energy in accordance with experimental studies. Also, estimated rate constants are in reasonable agreement with experimental values for a wide range of temperatures. Our calculations showed that both negative and positive ethyl ions readily react with methane, forming hydrogen molecules and C3 ion radicals. However, the continued growth of these radicals encounters increasing activation barriers, suggesting a slowdown in the carbon ion clusterization rate and hydrogen production for larger clusters. These findings are crucial for carbon nanoparticle generation and hydrogen production using the plasma catalysis process.

Allogenic hematopoietic stem cell transplantation (HSCT) and gene therapy (GT) are potentially curative treatments for severe combined immunodeficiency (SCID). Late-onset posttreatment manifestations (such as persistent hepatitis) are not uncommon. We sought to characterize the prevalence and pathophysiology of persistent hepatitis in transplanted SCID patients (SCIDH+) and to evaluate risk factors and treatments. We used various techniques (including pathology assessments, metagenomics, single-cell transcriptomics, and cytometry by time of flight) to perform an in-depth study of different tissues from patients in the SCIDH+ group and corresponding asymptomatic similarly transplanted SCID patients without hepatitis (SCIDH-). Eleven patients developed persistent hepatitis (median of 6 years after HSCT or GT). This condition was associated with the chronic detection of enteric viruses (human Aichi virus, norovirus, and sapovirus) in liver and/or stools, which were not found in stools from the SCIDH- group (n= 12). Multiomics analysis identified an expansion of effector memory CD8+ Tcells with high type I and II interferon signatures. Hepatitis was associated with absence of myeloablation during conditioning, split chimerism, and defective B-cell function, representing 25% of the 44 patients with SCID having these characteristics. Partially myeloablative retransplantation or GT of patients with this condition (which we have named as "enteric virus infection associated with hepatitis") led to the reconstitution of T- and B-cell immunity and remission of hepatitis in 5 patients, concomitantly with viral clearance. Enteric virus infection associated with hepatitis is related to chronic enteric viral infection and immune dysregulation and is an important risk for transplanted SCID patients with defective B-cell function.

Background and aimsBeckman Coulter hematology analysers identify leukocytes by their volume (V), conductivity (C) and scatter (S) of a laser beam at different angles. Each leukocyte sub-population [neutrophils (NE), lymphocytes (LY), monocytes (MO)] is characterized by the mean (MN) and the standard deviation (SD) of 7 measurements called “cellular population data” (@CPD), corresponding to morphological analysis of the leukocytes. As severe forms of infections to SARS-CoV-2 are characterized by a functional activation of mononuclear cells, leading to a cytokine storm, we evaluated whether CPD variations are correlated to the inflammation state, oxygen requirement and lung damage and whether CPD analysis could be useful for a triage of patients with COVID-19 in the Emergency Department (ED) and could help to identify patients with a high risk of worsening. Materials and methodThe CPD of 825 consecutive patients with proven COVID-19 presenting to the ED were recorded and compared to classical biochemical parameters, the need for hospitalization in the ward or ICU, the need for oxygen, or lung injury on CT-scan. Results40 of the 42 CPD were significantly modified in COVID-19 patients in comparison to 245 controls. @MN-V-MO and @SD-V-MO were highly correlated with C-reactive protein, procalcitonin, ferritin and D-dimers. SD-UMALS-LY > 21.45 and > 23.92 identified, respectively, patients with critical lung injuries (>75%) and requiring tracheal intubation. @SD-V-MO > 25.03 and @SD-V-NE > 19.4 identified patients required immediate ICU admission, whereas a @MN-V-MO < 183 suggested that the patient could be immediately discharged. Using logistic regression, the combination of 8 CPD with platelet and basophil counts and the existence of diabetes or obesity could identify patients requiring ICU after a first stay in conventional wards (area under the curve = 0.843). ConclusionCPD analysis constitutes an easy and inexpensive tool for triage and prognosis of COVID-19 patients in the ED.

The method of precise cutting of 2D materials by simultaneous action of a catalyst at the tip of the scanning microscope probe and an electron beam in a high-resolution transmission electron microscope is proposed and studied using atomistic simulations by the example of graphene and a nickel catalyst. Reactive molecular dynamics simulations within the Compu-TEM approach for the description of electron impact effects show that the combination of the nickel catalyst and electron irradiation is crucial for graphene cutting. Cuts with straight edges with widths of about 1-1.5 nm can be obtained. The detailed atomistic mechanism of graphene cutting is investigated via the analysis of statistics on atom ejection and bond reorganization reactions induced by the irradiation. The principal and secondary channels of atom ejection which lead to propagation of the cut are shown to be ejection of two-coordinated atoms at the cut edges bonded to the nickel tip and three-coordinated atoms from the defective graphene structure near the tip. At the same time, the ejection of two-coordinated atoms not bonded to the tip and atoms in chains at the cut edges favors smoothing of free cut edges behind the tip. A considerable difference from the atomistic mechanism of cutting a carbon nanotube via the simultaneous action of electron irradiation and nickel catalyst is discussed. The ab initio calculations performed show a decrease of the binding energy of two-coordinated carbon atoms bonded to the nickel cluster in comparison with the same cut edge in the absence of the cluster confirming that the principal channel of atom ejection is related to the cut propagation.