51 research outputs found
Transport properties of Layer-Antiferromagnet CuCrS2: A possible thermoelectric material
The electrical, thermal conductivity and Seebeck coefficient of the quenched,
annealed and slowly cooled phases of the layer compound CuCrS2 have been
reported between 15K to 300K. We also confirm the antiferromagnetic transition
at 40K in them by our magnetic measurements between 2K and 300K. The crystal
flakes show a minimum around 100K in their in-plane resistance behavior. For
the polycrystalline pellets the resistivity depends on their flaky texture and
it attains at most 10 to 20 times of the room temperature value at the lowest
temperature of measurement. The temperature dependence is complex and no
definite activation energy of electronic conduction can be discerned. We find
that the Seebeck coefficient is between 200-450 microV/K and is unusually large
for the observed resistivity values of between 5-100 mOhm-cm at room
temperature. The figure of merit ZT for the thermoelectric application is 2.3
for our quenched phases, which is much larger than 1 for useful materials. The
thermal conductivity K is mostly due to lattice conduction and is reduced by
the disorder in Cu- occupancy in our quenched phase. A dramatic reduction of
electrical and thermal conductivity is found as the antiferromagnetic
transition is approached from the paramagnetic region, and K subsequently rises
in the ordered phase. We discuss the transport properties as being similar to a
doped Kondo-insulator
Vaccine breakthrough hypoxemic COVID-19 pneumonia in patients with auto-Abs neutralizing type I IFNs
Life-threatening `breakthrough' cases of critical COVID-19 are attributed to poor or waning antibody response to the SARS- CoV-2 vaccine in individuals already at risk. Pre-existing autoantibodies (auto-Abs) neutralizing type I IFNs underlie at least 15% of critical COVID-19 pneumonia cases in unvaccinated individuals; however, their contribution to hypoxemic breakthrough cases in vaccinated people remains unknown. Here, we studied a cohort of 48 individuals ( age 20-86 years) who received 2 doses of an mRNA vaccine and developed a breakthrough infection with hypoxemic COVID-19 pneumonia 2 weeks to 4 months later. Antibody levels to the vaccine, neutralization of the virus, and auto- Abs to type I IFNs were measured in the plasma. Forty-two individuals had no known deficiency of B cell immunity and a normal antibody response to the vaccine. Among them, ten (24%) had auto-Abs neutralizing type I IFNs (aged 43-86 years). Eight of these ten patients had auto-Abs neutralizing both IFN-a2 and IFN-., while two neutralized IFN-omega only. No patient neutralized IFN-ss. Seven neutralized 10 ng/mL of type I IFNs, and three 100 pg/mL only. Seven patients neutralized SARS-CoV-2 D614G and the Delta variant (B.1.617.2) efficiently, while one patient neutralized Delta slightly less efficiently. Two of the three patients neutralizing only 100 pg/mL of type I IFNs neutralized both D61G and Delta less efficiently. Despite two mRNA vaccine inoculations and the presence of circulating antibodies capable of neutralizing SARS-CoV-2, auto-Abs neutralizing type I IFNs may underlie a significant proportion of hypoxemic COVID-19 pneumonia cases, highlighting the importance of this particularly vulnerable population
Autoantibodies against type I IFNs in patients with life-threatening COVID-19
Interindividual clinical variability in the course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is vast. We report that at least 101 of 987 patients with life-threatening coronavirus disease 2019 (COVID-19) pneumonia had neutralizing immunoglobulin G (IgG) autoantibodies (auto-Abs) against interferon-w (IFN-w) (13 patients), against the 13 types of IFN-a (36), or against both (52) at the onset of critical disease; a few also had auto-Abs against the other three type I IFNs. The auto-Abs neutralize the ability of the corresponding type I IFNs to block SARS-CoV-2 infection in vitro. These auto-Abs were not found in 663 individuals with asymptomatic or mild SARS-CoV-2 infection and were present in only 4 of 1227 healthy individuals. Patients with auto-Abs were aged 25 to 87 years and 95 of the 101 were men. A B cell autoimmune phenocopy of inborn errors of type I IFN immunity accounts for life-threatening COVID-19 pneumonia in at least 2.6% of women and 12.5% of men
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