Picosecond Dynamics of Excited 9,9‘-Bianthryl Adsorbed on Porous Glass:  Role of Symmetry Breaking in the Ground State†

2002 ◽  
Vol 106 (10) ◽  
pp. 2067-2073 ◽  
Author(s):  
Yasuyuki Tsuboi ◽  
Tamami Kumagai ◽  
Masato Shimizu ◽  
Akira Itaya ◽  
Gerd Schweitzer ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Porous Glass ◽  
Ground State

Centrosome Aurora A gradient ensures single polarity axis in C. elegans embryos

2020 ◽  
Vol 48 (3) ◽  
pp. 1243-1253 ◽  
Author(s):  
Sukriti Kapoor ◽  
Sachin Kotak
Keyword(s):  
Symmetry Breaking ◽  
Cell Fate ◽  
Cell Cortex ◽  
Axis Formation ◽  
Aurora A Kinase ◽  
Aurora A ◽  
C Elegans ◽  
Cell Embryo ◽  
Polarity Establishment

Cellular asymmetries are vital for generating cell fate diversity during development and in stem cells. In the newly fertilized Caenorhabditis elegans embryo, centrosomes are responsible for polarity establishment, i.e. anterior–posterior body axis formation. The signal for polarity originates from the centrosomes and is transmitted to the cell cortex, where it disassembles the actomyosin network. This event leads to symmetry breaking and the establishment of distinct domains of evolutionarily conserved PAR proteins. However, the identity of an essential component that localizes to the centrosomes and promotes symmetry breaking was unknown. Recent work has uncovered that the loss of Aurora A kinase (AIR-1 in C. elegans and hereafter referred to as Aurora A) in the one-cell embryo disrupts stereotypical actomyosin-based cortical flows that occur at the time of polarity establishment. This misregulation of actomyosin flow dynamics results in the occurrence of two polarity axes. Notably, the role of Aurora A in ensuring a single polarity axis is independent of its well-established function in centrosome maturation. The mechanism by which Aurora A directs symmetry breaking is likely through direct regulation of Rho-dependent contractility. In this mini-review, we will discuss the unconventional role of Aurora A kinase in polarity establishment in C. elegans embryos and propose a refined model of centrosome-dependent symmetry breaking.

t+t clustering in He-isotopes

2006 ◽  
Vol 21 (31n33) ◽  
pp. 2499-2502
Author(s):  
S. Aoyama ◽  
N. Itagaki ◽  
K. Arai ◽  
K. Katō ◽  
M. Oi
Keyword(s):  
Configuration Space ◽  
Ground State ◽  
Cluster Component ◽  
Theoretical Approaches ◽  
He Isotopes

t+t clustering in He isotopes is investigated by using two theoretical approaches. A role of the t+t cluster component in the ground state is examined with AMD triple-S, allowing the wider configuration space containing simultaneously the "t+t+valence neutrons" structure and "4 He +valence neutrons" structure. We understand the importance of the t + t component even for the ground state. Further, t + t resonances are investigated with RGM type approach. We obtained many t + t states as resonances near to t + t threshold.

scholarly journals Instability of the marginal commutative model of tunneling centers interacting with a metallic environment: Role of the electron-hole symmetry breaking

1997 ◽  
Vol 56 (20) ◽  
pp. 12947-12960 ◽  
Author(s):  
A. Zawadowski ◽  
G. Zaránd ◽  
P. Nozières ◽  
K. Vladár ◽  
G. T. Zimányi
Keyword(s):  
Symmetry Breaking ◽  
Electron Hole ◽  
Tunneling Centers

Two-photon absorption spectra of a near-infrared 2-azaazulene polymethine dye: solvation and ground-state symmetry breaking

2013 ◽  
Vol 15 (20) ◽  
pp. 7666 ◽  
Author(s):  
Honghua Hu ◽  
Olga V. Przhonska ◽  
Francesca Terenziani ◽  
Anna Painelli ◽  
Dmitry Fishman ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Absorption Spectra ◽  
Ground State ◽  
Near Infrared ◽  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Polymethine Dye

scholarly journals Time-reversal symmetry breaking superconducting ground state in the doped Mott insulator on the honeycomb lattice

2013 ◽  
Vol 88 (15) ◽  
Author(s):  
Zheng-Cheng Gu ◽  
Hong-Chen Jiang ◽  
D. N. Sheng ◽  
Hong Yao ◽  
Leon Balents ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Ground State ◽  
Time Reversal ◽  
Mott Insulator ◽  
Honeycomb Lattice ◽  
Time Reversal Symmetry ◽  
Doped Mott Insulator

A meta-analysis and review examining a possible role for oxidative stress and singlet oxygen in diverse diseases

2017 ◽  
Vol 474 (16) ◽  
pp. 2713-2731 ◽  
Author(s):  
Athinoula L. Petrou ◽  
Athina Terzidaki
Keyword(s):  
Oxidative Stress ◽  
Excited State ◽  
Singlet Oxygen ◽  
Ground State ◽  
Meta Analysis ◽  
Common Mechanism ◽  
High Electron ◽  
A Value ◽  
First Excited State

From kinetic data (k, T) we calculated the thermodynamic parameters for various processes (nucleation, elongation, fibrillization, etc.) of proteinaceous diseases that are related to the β-amyloid protein (Alzheimer's), to tau protein (Alzheimer's, Pick's), to α-synuclein (Parkinson's), prion, amylin (type II diabetes), and to α-crystallin (cataract). Our calculations led to ΔG≠ values that vary in the range 92.8–127 kJ mol−1 at 310 K. A value of ∼10–30 kJ mol−1 is the activation energy for the diffusion of reactants, depending on the reaction and the medium. The energy needed for the excitation of O2 from the ground to the first excited state (1Δg, singlet oxygen) is equal to 92 kJ mol−1. So, the ΔG≠ is equal to the energy needed for the excitation of ground state oxygen to the singlet oxygen (1Δg first excited) state. The similarity of the ΔG≠ values is an indication that a common mechanism in the above disorders may be taking place. We attribute this common mechanism to the (same) role of the oxidative stress and specifically of singlet oxygen, (1Δg), to the above-mentioned processes: excitation of ground state oxygen to the singlet oxygen, 1Δg, state (92 kJ mol−1), and reaction of the empty π* orbital with high electron density regions of biomolecules (∼10–30 kJ mol−1 for their diffusion). The ΔG≠ for cases of heat-induced cell killing (cancer) lie also in the above range at 310 K. The present paper is a review and meta-analysis of literature data referring to neurodegenerative and other disorders.

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