Elastic, thermodynamic, and electronic properties of MnSi, FeSi, and CoSi

Measurements of the sound velocities, heat capacities, magnetic susceptibilities, and electrical resistivities of single crystals of MnSi, FeSi, and CoSi were performed in the temperature range 2.5–300 K and the elastic constants were calculated. The temperature dependence of the mentioned quantities reveals nontrivial features, reflecting specifics of magnetic and electron subsystems in these materials

Magnetic phase transition in the itinerant helimagnet MnSi: Thermodynamic and transport properties

A careful study of thermodynamic and transport properties of a high-quality single crystal of MnSi at ambient pressure suggests that its transition to a helical magnetic state near 29 K is weakly first order. The heat capacity, temperature derivative of resistivity, thermal expansion, and magnetic susceptibility exhibit a specific structure around the phase transition point, interpreted as a combination of first- and second-order features. Striking mirror symmetry between the temperature derivative of resistivity and the thermal expansion coefficient is observed. Conclusions drawn from these experiments question prevailing views on the phase diagram of MnSi

Magnetic phase transition in the itinerant helimagnet MnSi: Thermodynamic and transport properties

A careful study of thermodynamic and transport properties of a high-quality single crystal of MnSi at ambient pressure suggests that its transition to a helical magnetic state near 29 K is weakly first order. The heat capacity, temperature derivative of resistivity, thermal expansion, and magnetic susceptibility exhibit a specific structure around the phase transition point, interpreted as a combination of first- and second-order features. Striking mirror symmetry between the temperature derivative of resistivity and the thermal expansion coefficient is observed. Conclusions drawn from these experiments question prevailing views on the phase diagram of MnSi.This article is from Physical Review B 76 (2007): 052405, doi:10.1103/PhysRevB.76.052405.</p

Mosaicism in preimplantation human embryos

Since the very first publications on preimplantation genetic testing, researchers have faced a serious problem — a high mosaicism level in the preimplantation human embryos obtained by means of in vitro fertilization cycles. The nature of this mosaicism and its high impact on embryo development draws attention to this issue. In this research we studied the cells from different parts of preimplantation human embryos with mosaicism in the trophectoderm cells detected using Next-generation Sequencing (NGS). Six human blastocysts with mosaicism in their trophectoderm cells were each sectioned in three parts: two containing only trophectoderm cells and one predominantly inner cell mass. These parts were then analyzed individually. Our data indicate that the proportion of aneuploid cells in bioptate taken for preimplantation genetic testing does not necessarily reflect the true chromosomal status of the whole embryo and cannot be extrapolated to that in the embryoblast cells. The results of our study strongly suggest that mosaicism revealed in blastocyst reduces the likelihood of finding the euploid chromosome set in the other parts of the embryo. Karyotypes of cells from different parts of mosaic embryos show low concordance. Chromosomal abnormalities in mosaic embryos are unpredictably diverse, which may lead not only to loss of conception, but also to the development of genetic disease in the offspring. According to our data, the mosaic rate tends to increase in the samples containing trophectoderm adjacent to the embryoblast, which may have physiological significance for the implantation. Comparative studies focused on the concordance of mosaicism level of and the type of chromosomal abnormalities detected in different parts of preimplantation human embryos will improve clinical recommendations regarding the transfer of mosaic embryos

Identification of Genetic Risk Factors of Severe COVID-19 Using Extensive Phenotypic Data: A Proof-of-Concept Study in a Cohort of Russian Patients

The COVID-19 pandemic has drawn the attention of many researchers to the interaction between pathogen and host genomes. Over the last two years, numerous studies have been conducted to identify the genetic risk factors that predict COVID-19 severity and outcome. However, such an analysis might be complicated in cohorts of limited size and/or in case of limited breadth of genome coverage. In this work, we tried to circumvent these challenges by searching for candidate genes and genetic variants associated with a variety of quantitative and binary traits in a cohort of 840 COVID-19 patients from Russia. While we found no gene- or pathway-level associations with the disease severity and outcome, we discovered eleven independent candidate loci associated with quantitative traits in COVID-19 patients. Out of these, the most significant associations correspond to rs1651553 in MYH14p = 1.4 &times; 10&minus;7), rs11243705 in SETX (p = 8.2 &times; 10&minus;6), and rs16885 in ATXN1 (p = 1.3 &times; 10&minus;5). One of the identified variants, rs33985936 in SCN11A, was successfully replicated in an independent study, and three of the variants were found to be associated with blood-related quantitative traits according to the UK Biobank data (rs33985936 in SCN11A, rs16885 in ATXN1, and rs4747194 in CDH23). Moreover, we show that a risk score based on these variants can predict the severity and outcome of hospitalization in our cohort of patients. Given these findings, we believe that our work may serve as proof-of-concept study demonstrating the utility of quantitative traits and extensive phenotyping for identification of genetic risk factors of severe COVID-19