Characteristic Polynomial in Assessment of Carbon-Nano Structures

Author(s):  
Sorana D. Bolboacă ◽  
Lorentz Jäntschi

Six dodecahedrane assemblies as multiple of five and respectively six structures were constructed and investigated from the topological point of view. The investigation was conducted using characteristic polynomials, graph invariant encoding important properties of the graph of the chemical structure. The assemblies of 5, 6, 15 and 25 dodecahedranes proved to have the center in the same plane while the assemblies of 12 and 24 dodecahedranes degenerated from the planar central form to a chair conformation. Generally, the number of real roots of characteristic polynomials is equal to the number of atoms in the assembly. The obtained roots of the characteristic polynomial were split into intervals and the frequency apparition spectra were simulated. The obtained spectra were used to investigate the behavior of investigated assembly.

2021 ◽  
Vol 22 (8) ◽  
pp. 4203
Author(s):  
Giorgio Valabrega ◽  
Giulia Scotto ◽  
Valentina Tuninetti ◽  
Arianna Pani ◽  
Francesco Scaglione

Poly(ADP-ribose) polymerases (PARP) are proteins responsible for DNA damage detection and signal transduction. PARP inhibitors (PARPi) are able to interact with the binding site for PARP cofactor (NAD+) and trapping PARP on the DNA. In this way, they inhibit single-strand DNA damage repair. These drugs have been approved in recent years for the treatment of ovarian cancer. Although they share some similarities, from the point of view of the chemical structure and pharmacodynamic, pharmacokinetic properties, these drugs also have some substantial differences. These differences may underlie the different safety profiles and activity of PARPi.


2014 ◽  
Vol 284 ◽  
pp. 60-69
Author(s):  
Mariola Wicka ◽  
◽  
Piotr Chołbiński ◽  
Dorota Kwiatkowska ◽  
Andrzej Pokrywka ◽  
...  

Year on year, one can observe an increase in the use of addictive substances. This leads to occurring the problem of addiction as well as the use of psychoactive substances as a serious hazard to road users. The Regulation of the Minister of Health on agents acting similarly to alcohol and the conditions and manner of conducting research on their presence in the human body, requires adequate benchmarks for performing these tests. An importantfactor, from consultative point of view, is the knowledge of the chemical structure of substances belonging to different groups of drugs of abuse, their metabolic transformations that occur in the body as well as their influence on the body. This is to aid in the proper interpretation of the results of the analytical tests.


1960 ◽  
Vol 199 (6) ◽  
pp. 1008-1010 ◽  
Author(s):  
C.S. Narayana Setty ◽  
A. C. Ivy

A basal sterol-free diet consisting of casein, 18%; dextrin, 57%; oleic acid, 9%; U.S.P. salt mixture, 2%; yeast, 5%; and cellulose, 9%; along with 1% sulfasuxidine and 0.2% streptomycin sulfate was fed to eight rats during a control period of 12 days, the feces being collected under alcohol the last 4 days and assayed for digitonide sterol. The experiment was repeated with the addition of 28 mg of coprostanol to the diet. It was found that from 41 to 61% (average 48%) of the coprostanol was absorbed. The relation of chemical structure to the absorbability of cholesterol derivatives is discussed with the finding that all absorbable cholesterol derivatives have the ‘chair’ conformation, but are not alike in digitonide formation and Liebermann-Burchard color reaction.


2007 ◽  
Vol 2007 ◽  
pp. 1-8
Author(s):  
Takashi Uno

We estimate a lower bound for the number of real roots of a random alegebraic equation whose random coeffcients are dependent normal random variables.


1973 ◽  
Vol 52 ◽  
pp. 405-412 ◽  
Author(s):  
Mikio Shimizu

The analysis of the abundance of interstellar molecules in compact H II regions suggests that the molecules are formed in stellar atmospheres (possibly of protostars or of late type stars), transported to the location of the neutral clouds in the cpmpact H II regions, and shielded from decomposition due to stellar radiation by the dust in the clouds. Cometary nuclei and interstellar dust are argued from the astrochemical point of view to be dirty ice of the second kind (or a sort of frozen interstellar molecules). The chemical structure of the primordial solar nebula is discussed under the assumption that long-period comets consist of the most primordial substances of the solar system.


2018 ◽  
Vol 146 (12) ◽  
pp. 5437-5449 ◽  
Author(s):  
D. Armentano ◽  
J-M. Azaïs ◽  
F. Dalmao ◽  
J. R. León

Author(s):  
Rajesh Pavan Sunkari ◽  
Linda C. Schmidt

The kinematic chain isomorphism problem is one of the most challenging problems facing mechanism researchers. Methods using the spectral properties, characteristic polynomial and eigenvectors, of the graph related matrices were developed in literature for isomorphism detection. Detection of isomorphism using only the spectral properties corresponds to a polynomial time isomorphism detection algorithm. However, most of the methods used are either computationally inefficient or unreliable (i.e., failing to identify non-isomorphic chains). This work establishes the reliability of using the characteristic polynomial of the Laplace matrix for isomorphism detection of a kinematic chain. The Laplace matrix of a graph is used extensively in the field of algebraic graph theory for characterizing a graph using its spectral properties. The reliability in isomorphism detection of the characteristic polynomial of the Laplace matrix was comparable with that of the adjacency matrix. However, using the characteristic polynomials of both the matrices is superior to using either method alone. In search for a single matrix whose characteristic polynomial unfailingly detects isomorphism, novel matrices called the extended adjacency matrices are developed. The reliability of the characteristic polynomials of these matrices is established. One of the proposed extended adjacency matrices is shown to be the best graph matrix for isomorphism detection using the characteristic polynomial approach.


2004 ◽  
Vol 2004 (31) ◽  
pp. 1617-1622
Author(s):  
Bau-Sen Du

Letn≥2be an integer and letP={1,2,…,n,n+1}. LetZpdenote the finite field{0,1,2,…,p−1}, wherep≥2is a prime. Then every mapσonPdetermines a realn×nPetrie matrixAσwhich is known to contain information on the dynamical properties such as topological entropy and the Artin-Mazur zeta function of the linearization ofσ. In this paper, we show that ifσis acyclicpermutation onP, then all such matricesAσare similar to one another overZ2(but not overZpfor any primep≥3) and their characteristic polynomials overZ2are all equal to∑k=0nxk. As a consequence, we obtain that ifσis acyclicpermutation onP, then the coefficients of the characteristic polynomial ofAσare all odd integers and hence nonzero.


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