Microstructure evolution in high-entropy alloy CoCrFeNiMn during plane-strain multipass rolling to a thickness strain of 80% at 293 and 77 K was studied. Deformation at both temperatures was found to ...be accompanied by twinning. At 77 K, twinning was more extensive in terms of the fraction of twinned grains and the length of the twinning stage thereby providing faster kinetics of the microstructure evolution. Micro-shear bands formed in the microstructure of the alloy at the late stages of rolling (at ε ≈ 80% at 293 K and ε ≈ 40% at 77 K). The ultimate tensile strength of specimens rolled at 77 K or 293 K was found to be 1500 or 1200 MPa, respectively while the strength in the initial homogenized condition was 440 MPa. The contribution of various mechanisms to the hardening of the alloy following rolling at 77 K and 293 K was analyzed quantitatively.
•Microstructure evolution in CoCrFeNiMn during rolling at 77 and 293 K was studied.•Twinning, accompanied deformation at both temperatures, was more extensive at 77 K.•Shear bands formed at the late stages of deformation.•At both temperatures twin boundaries had less hardening effect than dislocations.•Rolling to e = 80% at 77 and 293 K yielded strength of 1500 and 1200 MPa, respectively.
An extended microscopic version of the interacting-boson model is developed. The properties of yrast-band states in even cerium isotopes up to the spin–parity of
are calculated on the basis of this ...model. These spin values include those at which band crossing occurs. The model parameters are calculated on the basis of employing an average spherical potential and residual multipole forces. An extension of the model is accomplished via taking into account high-spin quasiparticle pairs, whereby a satisfactory description of energies and
values was obtained without introducing effective charges. The present investigation is a continuation of a similar analysis of the properties of low-lying collective states in even xenon and barium isotopes.
COVID-19 is a global pandemic caused by the SARS-CoV-2 coronavirus. T cells play a key role in the adaptive antiviral immune response by killing infected cells and facilitating the selection of ...virus-specific antibodies. However, neither the dynamics and cross-reactivity of the SARS-CoV-2-specific T-cell response nor the diversity of resulting immune memory is well understood. In this study, we use longitudinal high-throughput T-cell receptor (TCR) sequencing to track changes in the T-cell repertoire following two mild cases of COVID-19. In both donors, we identified CD4
and CD8
T-cell clones with transient clonal expansion after infection. We describe characteristic motifs in TCR sequences of COVID-19-reactive clones and show preferential occurrence of these motifs in publicly available large dataset of repertoires from COVID-19 patients. We show that in both donors, the majority of infection-reactive clonotypes acquire memory phenotypes. Certain T-cell clones were detected in the memory fraction at the pre-infection time point, suggesting participation of pre-existing cross-reactive memory T cells in the immune response to SARS-CoV-2.
A further development of the expanded microscopic version of the IBM is presented by considering two-quasiparticle phonons with multipolarity up to
. The developed theoretical scheme is applied to ...describe the properties of the yrast-band states in
Cm up to spin 34
. This heavy transactinide nucleus is the only nucleus in this mass region where the values of
up to spin
are measured. That is why it is considered foremost, because this information allows testing the presented theoretical scheme based on a larger volume of experimental data. The region of transactinide nuclei differs from lighter ones by the absence of the effect of the back bending in the moment of inertia dependence on the square of the rotation frequency up to the spin
. This article is intended in particular to find out the reason for this effect. Peculiar properties of the rotational bands in heavy and superheavy nuclei are discussed.
T cells play a vital role in combatting SARS-CoV-2 and forming long-term memory responses. Whereas extensive structural information is available on neutralizing antibodies against SARS-CoV-2, such ...information on SARS-CoV-2-specific T-cell receptors (TCRs) bound to their peptide-MHC targets is lacking. Here we determine the structures of a public and a private TCR from COVID-19 convalescent patients in complex with HLA-A2 and two SARS-CoV-2 spike protein epitopes (YLQ and RLQ). The structures reveal the basis for selection of particular TRAV and TRBV germline genes by the public but not the private TCR, and for the ability of the TCRs to recognize natural variants of RLQ but not YLQ. Neither TCR recognizes homologous epitopes from human seasonal coronaviruses. By elucidating the mechanism for TCR recognition of an immunodominant yet variable epitope (YLQ) and a conserved but less commonly targeted epitope (RLQ), this study can inform prospective efforts to design vaccines to elicit pan-coronavirus immunity.
The experimental energies of yrast-band states are known up to the spin of
for some Pu, Cm, Fm, and No isotopes—in particular, for
Cm. Their unique property is that all states of very long bands in ...them remain purely collective. The collective character of these bands manifests itself in the fact that the band energies are faithfully reproduced within the phenomenology of the interacting-boson model (IBM1). The uncertainty in the parameters of the model used becomes smaller upon imposing the condition that the deformation-energy depth obtained on the basis of realistic interactions is equal to the deformation-energy depth calculated for the intrinsic state with the values found for the parameters of the IBM1 Hamiltonian.
The effect of annealing on the porous structure formed upon deformation of poly(ethylene terephthalate) (PET) in a physically active liquid medium has been studied by means of small-angle X-ray ...scattering. Isometric annealing of the crazed polymer at temperatures below
T
g
has been ccompanied by decrease in specific surface area of the fibrils connecting the walls of the crazes, the bulk porosity remaining unchanged. During PET annealing at temperatures exceeding
T
g
, reduction in the dispersion of the fibrillated material of crazes has been accompanied by decrease in the volume of microvoids, more pronounced at higher treatment temperature. The obtained results have been analyzed from the point of view of changes in the structure of crazes during annealing.
To determine the immunogenicity, efficacy, reactogenicity, and safety of a single dose of recombinant adenovirus type-5 vectored COVID-19 vaccine (Ad5-nCoV, 5 × 1010 viral particles per 0.5 mL dose), ...we conducted a single-dose, randomised, double-blind, placebo-controlled, parallel group (3:1 Ad5-nCoV:placebo), phase 3 trial (Prometheus).
From 11-September-2020 to 05-May-2021, across six sites in the Russian Federation, 496 participants were injected with either placebo or Ad5-nCoV expressing the full-length spike (S) protein from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
Seroconversion (the primary endpoint) rates of 78.5% (95% CI: 73.9; 82.6) against receptor binding domain (RBD), 90.6% (95% CI: 87.2; 93.4) against S protein and 59.0% (95% CI: 53.3; 64.6) seroconversion of neutralising antibodies against SARS-CoV-2 at 28 days post-vaccination were observed. Geometric mean titres (GMTs) were also elevated for antibodies against the RBD (405 95% CI: 366; 449) and S protein (677 95% CI: 608; 753) compared to the GMT of neutralising antibodies against SARS-CoV-2 (16.7 95% CI: 15.3; 18.3). Using an IFN-γ ELISpot assay after stimulating the cells with recombinant S protein ectodomain we showed that the Ad5-nCoV vaccine induced the most robust cellular immune response on Days 14 and 28. Up to Day 28, the primary and all secondary endpoints of the Ad5-nCoV vaccine were statistically significant compared with the placebo (р<0.001). Systemic reactions were reported in 113 of 496 (22.8%) participants (Ad5-nCoV, 26.9%; Placebo, 10.5%), and local reactions were reported in 108 (21.8%) participants (Ad5-nCoV, 28.5%; Placebo, 1.6%). These were generally mild and resolved within 7 days after vaccination. Of the six serious adverse events reported, none of the events were vaccine related. There were no deaths or premature withdrawals.
A single-dose of Ad5-nCoV vaccine induced a marked specific humoral and cellular immune response with a favourable safety profile.
Trial registration: ClinicalTrials.gov: NCT04540419.
On the basis of an extended microscopic version of the interacting-boson model (IBM1), yrast-band states in
Dy are described up to the spin–parity of
. Some states of this bands, the
,
, and
ones, ...are populated from the
excitation that lies at 2.788 MeV and whose population is in turn due to the
EC decay of the
isomeric state in
Ho.
We present radiation mechanism exhibited by a higher order soliton. In a course of its evolution the higher-order soliton emits polychromatic radiation resulting in formation of multipeak frequency ...comb-like spectral band. The shape and spectral position of this band can be effectively controlled by the relative strength of the third order dispersion. An analytical description is corroborated by numerical simulations. It is shown that for longer pulses the described effect persists also under the action of higher order perturbations such as Raman and self-steepening.
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