REWRITING LOGIC-BASED SEMANTICS OF P SYSTEMS AND THE MAXIMAL CONCURRENCY

2009 ◽  
Vol 20 (03) ◽  
pp. 395-410
Author(s):  
DOREL LUCANU
Keyword(s):  
Modal Logics ◽  
P Systems ◽  
Rewriting Logic ◽  
Membrane Interactions ◽  
Transition Systems ◽  
Interleaving Semantics

We use distributed labeled transition systems and their modal logics in order to compare the concurrency degrees of the P systems and their encoding as rewrite theories in rewriting logic. We show that the maximal concurrency given by the maximal parallel rewriting semantics of the P systems can be expressed in rewriting logic only by interleaving semantics. The maximal concurrency of the membrane interactions is only partially captured.

A Non-Interleaving Semantics for CCS Based on Proved Transitions

1988 ◽  
Vol 11 (4) ◽  
pp. 433-452 ◽  
Author(s):  
Gérard Boudol ◽  
Ilaria Castellani
Keyword(s):  
Partial Order ◽  
Transition Systems ◽  
Structural Rules ◽  
Labelled Transition Systems ◽  
Interleaving Semantics ◽  
Partial Order Semantics ◽  
The Given

When using labelled transition systems to model languages like CCS or TCSP, one specifies transitions by a set of structural rules. We consider labelling transitions with their proofs – in the given system of rules – instead of simple actions. Then the label of a transition identifies uniquely that transition, and one may use this information to define a concurrency relation on (proved) transitions, and a notion of residual of a (proved) transition by a concurrent one. We apply Berry and Lévy’s notion of equivalence by permutations to sequences of proved transitions for CCS to obtain a partial order semantics for this language.

scholarly journals CCS Semantics via Proved Transition Systems and Rewriting Logic

1998 ◽  
Vol 15 ◽  
pp. 369-387 ◽  
Author(s):  
Georgia Carabetta ◽  
Pierpaolo Degano ◽  
Fabio Gadducci
Keyword(s):  
Rewriting Logic ◽  
Transition Systems

Trophoblast Cell Membrane Interactions at Implantation

1970 ◽  
Vol 28 ◽  
pp. 310-311
Author(s):  
A. C. Enders
Keyword(s):  
Epithelial Cells ◽  
Cell Membrane ◽  
Membrane Fusion ◽  
Trophoblast Cell ◽  
Membrane Interactions ◽  
Uterine Epithelial Cells ◽  
Functional Complex ◽  
Cytotrophoblast Cells ◽  
Complex Relationships ◽  
Syncytial Trophoblast

The alteration in membrane relationships seen at implantation include 1) interaction between cytotrophoblast cells to form syncytial trophoblast and addition to the syncytium by subsequent fusion of cytotrophoblast cells, 2) formation of a wide variety of functional complex relationships by trophoblast with uterine epithelial cells in the process of invasion of the endometrium, and 3) in the case of the rabbit, fusion of some uterine epithelial cells with the trophoblast.Formation of syncytium is apparently a membrane fusion phenomenon in which rapid confluence of cytoplasm often results in isolation of residual membrane within masses of syncytial trophoblast. Often the last areas of membrane to disappear are those including a desmosome where the cell membranes are apparently held apart from fusion.

Symmetry Breaking and the Turn-On Fluorescence of Small, Highly Strained Carbon Nanohoops

2019 ◽  
Author(s):  
Terri Lovell ◽  
Curtis Colwell ◽  
Lev N. Zakharov ◽  
Ramesh Jasti
Keyword(s):  
Symmetry Breaking ◽  
Theoretical Work ◽  
P Systems ◽  
Quantum Yields ◽  
Size Dependent ◽  
New Class ◽  
Carbon Carbon Bond ◽  
Conjugated Macrocycles ◽  
Structural Manipulation ◽  
Highly Strained

<p>[<i>n</i>]Cycloparaphenylenes, or “carbon nanohoops,” are unique conjugated macrocycles with radially oriented p-systems similar to those in carbon nanotubes. The centrosymmetric nature and conformational rigidity of these molecules lead to unusual size-dependent photophysical characteristics. To investigate these effects further and expand the family of possible structures, a new class of related carbon nanohoops with broken symmetry is disclosed. In these structures, referred to as <i>meta</i>[<i>n</i>]cycloparaphenylenes, a single carbon-carbon bond is shifted by one position in order to break the centrosymmetric nature of the parent [<i>n</i>]cycloparaphenylenes. Advantageously, the symmetry breaking leads to bright emission in the smaller nanohoops, which are typically non-fluorescent due to optical selection rules. Moreover, this simple structural manipulation retains one of the most unique features of the nanohoop structures-size dependent emissive properties with relatively large extinction coefficents and quantum yields. Inspired by earlier theoretical work by Tretiak and co-workers, this joint synthetic, photophysical, and theoretical study provides further design principles to manipulate the optical properties of this growing class of molecules with radially oriented p-systems.</p>

Symmetry Breaking and the Turn-On Fluorescence of Small, Highly Strained Carbon Nanohoops

2019 ◽  
Author(s):  
Terri Lovell ◽  
Curtis Colwell ◽  
Lev N. Zakharov ◽  
Ramesh Jasti
Keyword(s):  
Symmetry Breaking ◽  
Theoretical Work ◽  
P Systems ◽  
Quantum Yields ◽  
Size Dependent ◽  
New Class ◽  
Carbon Carbon Bond ◽  
Conjugated Macrocycles ◽  
Structural Manipulation ◽  
Highly Strained

<p>[<i>n</i>]Cycloparaphenylenes, or “carbon nanohoops,” are unique conjugated macrocycles with radially oriented p-systems similar to those in carbon nanotubes. The centrosymmetric nature and conformational rigidity of these molecules lead to unusual size-dependent photophysical characteristics. To investigate these effects further and expand the family of possible structures, a new class of related carbon nanohoops with broken symmetry is disclosed. In these structures, referred to as <i>meta</i>[<i>n</i>]cycloparaphenylenes, a single carbon-carbon bond is shifted by one position in order to break the centrosymmetric nature of the parent [<i>n</i>]cycloparaphenylenes. Advantageously, the symmetry breaking leads to bright emission in the smaller nanohoops, which are typically non-fluorescent due to optical selection rules. Moreover, this simple structural manipulation retains one of the most unique features of the nanohoop structures-size dependent emissive properties with relatively large extinction coefficents and quantum yields. Inspired by earlier theoretical work by Tretiak and co-workers, this joint synthetic, photophysical, and theoretical study provides further design principles to manipulate the optical properties of this growing class of molecules with radially oriented p-systems.</p>

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