Band structure of semimagnetic Hg1-yMnyTe quantum wells

The band structure of semimagnetic Hg_1-yMn_yTe/Hg_1-xCd_xTe type-III quantum wells has been calculated using eight-band kp model in an envelope function approach. Details of the band structure calculations are given for the Mn free case (y=0). A mean field approach is used to take the influence of the sp-d exchange interaction on the band structure of QW's with low Mn concentrations into account. The calculated Landau level fan diagram and the density of states of a Hg_0.98Mn_0.02Te/Hg_0.3Cd_0.7Te QW are in good agreement with recent experimental transport observations. The model can be used to interpret the mutual influence of the two-dimensional confinement and the sp-d exchange interaction on the transport properties of Hg_1-yMn_yTe/Hg_1-xCd_xTe QW's.Comment: 12 pages, 4 figure

Computer simulations of domain growth and phase separation in two-dimensional binary immiscible fluids using dissipative particle dynamics

We investigate the dynamical behavior of binary fluid systems in two dimensions using dissipative particle dynamics. We find that following a symmetric quench the domain size R(t) grows with time t according to two distinct algebraic laws R(t) = t^n: at early times n = 1/2, while for later times n = 2/3. Following an asymmetric quench we observe only n = 1/2, and if momentum conservation is violated we see n = 1/3 at early times. Bubble simulations confirm the existence of a finite surface tension and the validity of Laplace's law. Our results are compared with similar simulations which have been performed previously using molecular dynamics, lattice-gas and lattice-Boltzmann automata, and Langevin dynamics. We conclude that dissipative particle dynamics is a promising method for simulating fluid properties in such systems.Comment: RevTeX; 22 pages, 5 low-resolution figures. For full-resolution figures, connect to http://www.tcm.phy.cam.ac.uk/~ken21/tension/tension.htm

Spinodal decomposition of off-critical quenches with a viscous phase using dissipative particle dynamics in two and three spatial dimensions

We investigate the domain growth and phase separation of hydrodynamically-correct binary immiscible fluids of differing viscosity as a function of minority phase concentration in both two and three spatial dimensions using dissipative particle dynamics. We also examine the behavior of equal-viscosity fluids and compare our results to similar lattice-gas simulations in two dimensions.Comment: 34 pages (11 figures); accepted for publication in Phys. Rev.

The Quantum Spin Hall Effect: Theory and Experiment

The search for topologically non-trivial states of matter has become an important goal for condensed matter physics. Recently, a new class of topological insulators has been proposed. These topological insulators have an insulating gap in the bulk, but have topologically protected edge states due to the time reversal symmetry. In two dimensions the helical edge states give rise to the quantum spin Hall (QSH) effect, in the absence of any external magnetic field. Here we review a recent theory which predicts that the QSH state can be realized in HgTe/CdTe semiconductor quantum wells. By varying the thickness of the quantum well, the band structure changes from a normal to an "inverted" type at a critical thickness $d_c$. We present an analytical solution of the helical edge states and explicitly demonstrate their topological stability. We also review the recent experimental observation of the QSH state in HgTe/(Hg,Cd)Te quantum wells. We review both the fabrication of the sample and the experimental setup. For thin quantum wells with well width $d_{QW}< 6.3$ nm, the insulating regime shows the conventional behavior of vanishingly small conductance at low temperature. However, for thicker quantum wells ($d_{QW}> 6.3$ nm), the nominally insulating regime shows a plateau of residual conductance close to $2e^2/h$. The residual conductance is independent of the sample width, indicating that it is caused by edge states. Furthermore, the residual conductance is destroyed by a small external magnetic field. The quantum phase transition at the critical thickness, $d_c= 6.3$ nm, is also independently determined from the occurrence of a magnetic field induced insulator to metal transition.Comment: Invited review article for special issue of JPSJ, 32 pages. For higher resolution figures see official online version when publishe

Ultrapotent antibodies against diverse and highly transmissible SARS-CoV-2 variants

IC80 1.5 to 34.5 nanograms per milliliter). We define the structural and functional determinants of binding for all four VOC-targeting antibodies and show that combinations of two antibodies decrease the in vitro generation of escape mutants, suggesting their potential in mitigating resistance development.The emergence of highly transmissible SARS-CoV-2 variants of concern (VOCs) that are resistant to therapeutic antibodies highlights the need for continuing discovery of broadly reactive antibodies. We identified four receptor binding domain-targeting antibodies from three early-outbreak convalescent donors with potent neutralizing activity against 23 variants, including the B.1.1.7, B.1.351, P.1, B.1.429, B.1.526, and B.1.617 VOCs. Two antibodies are ultrapotent, with subnanomolar neutralization titers [half-maximal inhibitory concentration (IC50) 0.3 to 11.1 nanograms per millilite

Бронхиальная астма: федеральные клинические рекомендации по диагностике и лечению

Bronchial asthma is a heterogeneous disease that requires identification of its phenotype and a personalized approach to therapy. At the same time, despite a wide range of therapeutic options, many patients with asthma cannot achieve control over the disease.Methodology. The target audience of these clinical recommendations are general practitioners, therapists, pediatricians, allergologists-immunologists, pulmonologists, and functional diagnostics doctors. Each thesis-recommendation about diagnostic and therapeutic procedures has been scored according to the scales of classes of recommendations from 1 to 5 and A, B, C scale of the levels of evidence. The clinical recommendations also contain comments and explanations to the theses, algorithms for the diagnosis and treatment of bronchial asthma, and reference materials.Conclusion. The presented clinical guidelines cover current information about the etiology and pathogenesis, classification, clinical manifestations, diagnosis, treatment, and prevention of bronchial asthma. These guidelines were approved by the Scientific and Practical Council of the Ministry of Health of the Russian Federation in 2021. Бронхиальная астма (БА) является гетерогенным заболеванием, при котором требуется выделение различных фенотипов и персонифицированный подход к терапии. При этом несмотря на широкий выбор терапевтических возможностей, у многих пациентов с БА не удается достичь контроля над заболеванием.Методы. Целевой аудиторией данных клинических рекомендаций являются врачи общей практики, терапевты, педиатры, аллергологи-иммунологи, пульмонологи и врачи функциональной диагностики. Каждый тезис-рекомендация по проведению диагностических и лечебных мероприятий оценивается по шкалам уровней достоверности доказательств от 1 до 5 и шкале оценки уровней убедительности рекомендаций по категориям А, В, С. Клинические рекомендации содержат также комментарии и разъяснения к указанным тезисам-рекомендациям, алгоритмы по диагностике и лечению БА, справочные материалы.Заключение. По данным представленных клинических рекомендаций освещаются современные сведения об этиологии и патогенезе, классификации, клинических проявлениях, диагностике, лечении и профилактике БА. Клинические рекомендации одобрены Научно-практическим Советом Министерства здравоохранения Российской Федерации (2021).

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead