scholarly journals Entropic Analysis of Mirror Symmetry Breaking in Chiral Hypercycles

Life ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 28 ◽  
Author(s):  
David Hochberg ◽  
Josep Ribó
Keyword(s):  
Symmetry Breaking ◽  
Entropy Production ◽  
Mirror Symmetry ◽  
Flow Reactor ◽  
Evolutionary Selection ◽  
Replicator System ◽  
Stoichiometric Network Analysis ◽  
Underlying Mechanisms ◽  
The Individual ◽  
Origin Of Homochirality

Replicators are fundamental to the origin of life and evolvability. Biology exhibits homochirality: only one of two enantiomers is used in proteins and nucleic acids. Thermodynamic studies of chemical replicators able to lead to homochirality shed valuable light on the origin of homochirality and life in conformity with the underlying mechanisms and constraints. In line with this framework, enantioselective hypercyclic replicators may lead to spontaneous mirror symmetry breaking (SMSB) without the need for additional heterochiral inhibition reactions, which can be an obstacle for the emergence of evolutionary selection properties. We analyze the entropy production of a two-replicator system subject to homochiral cross-catalysis which can undergo SMSB in an open-flow reactor. The entropy exchange with the environment is provided by the input and output matter flows, and is essential for balancing the entropy production at the non-equilibrium stationary states. The partial entropy contributions, associated with the individual elementary flux modes, as defined by stoichiometric network analysis (SNA), describe how the system’s internal currents evolve, maintaining the balance between entropy production and exchange, while minimizing the entropy production after the symmetry breaking transition. We validate the General Evolution Criterion, stating that the change in the chemical affinities proceeds in a way as to lower the value of the entropy production.

scholarly journals Chaotic oscillations, dissipation and mirror symmetry breaking in a chiral catalytic network

2020 ◽  
Vol 22 (46) ◽  
pp. 27214-27223 ◽  
Author(s):  
David Hochberg ◽  
Antonio Sánchez Torralba ◽  
Federico Morán
Keyword(s):  
Symmetry Breaking ◽  
Entropy Production ◽  
Mirror Symmetry ◽  
Unit Volume ◽  
Flow Reactor ◽  
Chaotic Regime ◽  
Chaotic Oscillations ◽  
Open Flow ◽  
Catalytic Network

The entropy production per unit volume in the chaotic regime of a chiral hypercycle in an open-flow reactor.

Spontaneous mirror symmetry breaking: an entropy production survey of the racemate instability and the emergence of stable scalemic stationary states

2020 ◽  
Vol 22 (25) ◽  
pp. 14013-14025 ◽  
Author(s):  
Josep M. Ribó ◽  
David Hochberg
Keyword(s):  
Symmetry Breaking ◽  
Entropy Production ◽  
Mirror Symmetry ◽  
Flow System ◽  
Stationary States ◽  
Open Flow ◽  
Continuous Range ◽  
Non Equilibrium

Stability of non-equilibrium stationary states and spontaneous mirror symmetry breaking, provoked by the destabilization of the racemic thermodynamic branch, is studied for enantioselective autocatalysis in an open flow system, and for a continuous range n of autocatalytic orders.

Stoichiometric network analysis of spontaneous mirror symmetry breaking in chemical reactions

2017 ◽  
Vol 19 (27) ◽  
pp. 17618-17636 ◽  
Author(s):  
David Hochberg ◽  
Rubén D. Bourdon García ◽  
Jesús A. Ágreda Bastidas ◽  
Josep M. Ribó
Keyword(s):  
Network Analysis ◽  
Symmetry Breaking ◽  
Chemical Reactions ◽  
Chemical Reaction ◽  
Mirror Symmetry ◽  
Stoichiometric Network Analysis ◽  
Reaction Schemes

Stoichiometric network analysis (SNA) is used to study spontaneous mirror symmetry breaking in chemical reaction schemes.

scholarly journals Correction: Spontaneous mirror symmetry breaking: an entropy production survey of the racemate instability and the emergence of stable scalemic stationary states

2021 ◽  
Author(s):  
Josep M. Ribó ◽  
David Hochberg
Keyword(s):  
Symmetry Breaking ◽  
Entropy Production ◽  
Mirror Symmetry ◽  
Chem Phys ◽  
Stationary States ◽  
Phys Chem Chem Phys

Correction for ‘Spontaneous mirror symmetry breaking: an entropy production survey of the racemate instability and the emergence of stable scalemic stationary states’ by Josep M. Ribó et al., Phys. Chem. Chem. Phys., 2020, 22, 14013–14025, DOI: 10.1039/D0CP02280B.

2,6-Dibromogallates as a new building block for controlling π-stacking, network formation and mirror symmetry breaking

2021 ◽  
Author(s):  
Ohjin Kwon ◽  
Xiaoqian Cai ◽  
Azhar Saeed ◽  
Feng Liu ◽  
Silvio Poppe ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Building Block ◽  
Mirror Symmetry ◽  
Network Formation ◽  
Network Structures ◽  
Π Stacking ◽  
Bicontinuous Cubic ◽  
Substituted 1 ◽  
End Group

Achiral multi-chain (polycatenar) compounds based on the 2,7-diphenyl substituted [1]benzothieno[3,2-b]benzothiophene (BTBT) unit and a 2,6-dibromo-3,4,5-trialkoxybenzoate end group lead to materials forming bicontinuous cubic liquid crystaline phases with helical network structures...

scholarly journals Finding an easy way to harmonize: a review of advances in clinical research and combination strategies of EZH2 inhibitors

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Chen Li ◽  
Yan Wang ◽  
Yueqing Gong ◽  
Tengrui Zhang ◽  
Jiaqi Huang ◽  
...  
Keyword(s):  
Treatment Modalities ◽  
Preclinical Studies ◽  
Combination Therapies ◽  
Tumor Treatment ◽  
Antitumor Effects ◽  
Therapeutic Modalities ◽  
Combination Strategies ◽  
Anti Cancer ◽  
Underlying Mechanisms ◽  
The Individual

AbstractEnhancer of zeste homolog 2 inhibitors (EZH2i) have garnered increased attention owing to their anticancer activity by targeting EZH2, a well-known cancer-promoting factor. However, some lymphomas are resistant to EZH2i, and EZH2i treatment alone is ineffective in case of EZH2-overexpressing solid tumors. The anti-cancer efficacy of EZH2i may be improved through safe and effective combinations of these drugs with other treatment modalities. Preclinical evidence indicates that combining EZH2i with other therapies, such as immunotherapy, chemotherapy, targeted therapy, and endocrine therapy, has complementary or synergistic antitumor effects. Therefore, elucidating the underlying mechanisms of the individual constituents of the combination therapies is fundamental for their clinical application. In this review, we have summarized notable clinical trials and preclinical studies using EZH2i, their progress, and combinations of EZH2i with different therapeutic modalities, aiming to provide new insights for tumor treatment.

scholarly journals Magnetic Transitions in the Co-Modified Mn2Sb System

Inorganics ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 113 ◽  
Author(s):  
Johanna Wilden ◽  
Andreas Hoser ◽  
Mamuka Chikovani ◽  
Jörg Perßon ◽  
Jörg Voigt ◽  
...  
Keyword(s):  
Phase Transition ◽  
Magnetic Moments ◽  
Induction Melting ◽  
Magnetic Structures ◽  
Co Substitution ◽  
First Order Phase Transition ◽  
Phase Transition Temperatures ◽  
Underlying Mechanisms ◽  
The Individual ◽  
First Order Phase

Mn2Sb is ferrimagnetic below its Curie temperature (TC) and passes through a spin flip transition with decreasing temperature. The Co substitution induces an additional first-order phase transition from the ferrimagnetic (FRI) to an antiferromagnetic (AFM) state. This phase transition is connected to a sizable magnetocaloric effect (MCE). To understand the underlying mechanisms, the temperature dependence of structural and magnetic changes was analyzed. At the same time, the influence of the Co substitution was explored. Three Mn2−xCoxSb (x = 0.1, 0.15, 0.2) compounds were synthesized by cold crucible induction melting. Neutron powder diffraction was performed to determine the magnetic structures and to obtain the individual magnetic moments on both symmetrically independent Mn sites. In combination with the temperature-dependent magnetization measurements, the magnetic phase transition temperatures were identified. In the low-temperature range, additional antiferromagnetic peaks were detected, which could be indexed with a propagation vector of (0 0 ½). In Mn1.9Co0.1Sb at 50 K and in Mn1.8Co0.2Sb at 200 K, a co-existence of the FRI and the AFM state was observed. The pure AFM state only occurs in Mn1.8Co0.2Sb at 50 K.

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