Three-dimensional borophene: A light-element topological nodal-line semimetal with direction-dependent type-II Weyl fermions

2020 ◽  
Vol 102 (15) ◽  
Author(s):  
Leyuan Cui ◽  
Tielei Song ◽  
Jiangtao Cai ◽  
Xin Cui ◽  
Zhifeng Liu ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Light Element ◽  
Nodal Line ◽  
Type Ii ◽  
Dependent Type ◽  
Weyl Fermions

Collective modes of type-II Weyl fermions with repulsive S-wave interaction

2021 ◽  
Author(s):  
XunGao Wang ◽  
Yuan Sun ◽  
Liang Liu ◽  
WuMing Liu
Keyword(s):  
Fermi Surface ◽  
Random Phase ◽  
Three Dimensional ◽  
Wave Interaction ◽  
Repulsive Interaction ◽  
Type I ◽  
Type Ii ◽  
S Wave ◽  
Momentum Direction ◽  
Weyl Fermions

Abstract Three-dimensional type-II Weyl fermions possess overtilted conelike low-energy band dispersion. Unlike the closed ellipsoidal Fermi surface for type-I Weyl fermions, the Fermi surface is an open hyperboloid for type-II Weyl fermions. We evaluate the spin and density susceptibility of type-II Weyl fermions with repulsive S-wave interaction by means of Green’s functions. We obtain the particle-hole continuum along the tilted momentum direction and perpendicular to the tilted momentum direction, respectively. We find the zero sound mode in some repulsive interaction strengths by numerically solving the pole equations of the susceptibility within the random-phase approximation.

scholarly journals MnNBr Monolayer: A High‐Temperature Ferromagnetic Half‐Metal with Type‐II Weyl Fermions

2021 ◽  
Vol 15 (7) ◽  
pp. 2170027
Author(s):  
Yongting Shi ◽  
Lingjun Li ◽  
Xin Cui ◽  
Tielei Song ◽  
Zhifeng Liu
Keyword(s):  
High Temperature ◽  
Type Ii ◽  
Half Metal ◽  
Weyl Fermions

scholarly journals Type II degenerations of K3 surfaces

1985 ◽  
Vol 99 ◽  
pp. 11-30 ◽  
Author(s):  
Shigeyuki Kondo
Keyword(s):  
Number Field ◽  
Complex Manifold ◽  
Complex Number ◽  
Three Dimensional ◽  
K3 Surfaces ◽  
Type Ii ◽  
Holomorphic Map ◽  
Canonical Class ◽  
Proper Holomorphic Map ◽  
Complex Number Field

A degeneration of K3 surfaces (over the complex number field) is a proper holomorphic map π: X→Δ from a three dimensional complex manifold to a disc, such that, for t ≠ 0, the fibres Xt = π-1(t) are smooth K3 surfaces (i.e. surfaces Xt with trivial canonical class KXt = 0 and dim H1(Xt, Oxt) = 0).

scholarly journals Dirac and Nodal Line Magnons in Three-Dimensional Antiferromagnets

2017 ◽  
Vol 119 (24) ◽  
Author(s):  
Kangkang Li ◽  
Chenyuan Li ◽  
Jiangping Hu ◽  
Yuan Li ◽  
Chen Fang
Keyword(s):  
Three Dimensional ◽  
Nodal Line

GENETICS OF NON-INSULIN-DEPENDENT (TYPE-II) DIABETES MELLITUS

1996 ◽  
Vol 47 (1) ◽  
pp. 509-531 ◽  
Author(s):  
C. Ronald Kahn, M.D ◽  
David Vicent, M.D ◽  
Alessandro Doria, M.D., Ph.D
Keyword(s):  
Diabetes Mellitus ◽  
Type Ii Diabetes ◽  
Type Ii Diabetes Mellitus ◽  
Type Ii ◽  
Insulin Dependent ◽  
Dependent Type

scholarly journals Purification and Three-Dimensional Electron Microscopy Structure of the Neisseria meningitidis Type IV Pilus Biogenesis Protein PilG

2007 ◽  
Vol 189 (17) ◽  
pp. 6389-6396 ◽  
Author(s):  
Richard F. Collins ◽  
Muhammad Saleem ◽  
Jeremy P. Derrick
Keyword(s):  
Electron Microscopy ◽  
Neisseria Meningitidis ◽  
Metal Ion ◽  
Polyacrylamide Gel Electrophoresis ◽  
Three Dimensional ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Type Iv Pilus ◽  
Type Iv ◽  
Pilus Biogenesis

ABSTRACT Type IV pili are surface-exposed retractable fibers which play a key role in the pathogenesis of Neisseria meningitidis and other gram-negative pathogens. PilG is an integral inner membrane protein and a component of the type IV pilus biogenesis system. It is related by sequence to the extensive GspF family of secretory proteins, which are involved in type II secretion processes. PilG was overexpressed and purified from Escherichia coli membranes by detergent extraction and metal ion affinity chromatography. Analysis of the purified protein by perfluoro-octanoic acid polyacrylamide gel electrophoresis showed that PilG formed dimers and tetramers. A three-dimensional (3-D) electron microscopy structure of the PilG multimer was determined using single-particle averaging applied to samples visualized by negative staining. Symmetry analysis of the unsymmetrized 3-D volume provided further evidence that the PilG multimer is a tetramer. The reconstruction also revealed an asymmetric bilobed structure approximately 125 Å in length and 80 Å in width. The larger lobe within the structure was identified as the N terminus by location of Ni-nitrilotriacetic acid nanogold particles to the N-terminal polyhistidine tag. We propose that the smaller lobe corresponds to the periplasmic domain of the protein, with the narrower “waist” region being the transmembrane section. This constitutes the first report of a 3-D structure of a member of the GspF family and suggests a physical basis for the role of the protein in linking cytoplasmic and periplasmic protein components of the type II secretion and type IV pilus biogenesis systems.

Development of type II pneumocytes in rat lung

1991 ◽  
Vol 260 (2) ◽  
pp. L113-L122 ◽  
Author(s):  
S. L. Young ◽  
E. K. Fram ◽  
C. L. Spain ◽  
E. W. Larson
Keyword(s):  
Three Dimensional ◽  
Alveolar Epithelium ◽  
Type Ii Cells ◽  
Type Ii ◽  
Time Period ◽  
Type Ii Pneumocytes ◽  
Type Ii Cell ◽  
Membrane Type ◽  
Cytoplasmic Processes ◽  
Homogenous Population

At a late stage of fetal development, the mammalian alveolar epithelium undergoes an abrupt differentiation as a part of the preparation of the lung for the postnatal demands of gas exchange. Some of the most striking changes occur in the type II pneumocytes as they lose their glycogen and start to produce the lamellated inclusion granules that contain pulmonary surfactant. Premature birth before adequate type II cell maturation results in the neonatal respiratory distress syndrome, which is frequently fatal. We have used serial ultrathin sectioning, electron microscopy, and three-dimensional reconstructions to study the ultrastructural features of maturation of rat type II cells from a single rat each at age gestational day 20 through adult stages. We found evidence over this time span for compartmentation of several secretory granule precursors within type II cells. Changes in the polarization of lamellar bodies were observed over the time period studied. We also found marked gestational changes in the number and morphology of type II cell cytoplasmic processes that perforate the basement membrane. Type II cell mitochondria changed in shape during postnatal development from single, spherical to complex, branched structures. Volume composition obtained from serial sections of a small number of type II cells agreed closely with published morphometric data, indicating that throughout the animal's lifespan, type II cells are a homogenous population.

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