611 research outputs found
Electrically neutral Dirac particles in the presence of external fields: exact solutions
In the present article we present exact solutions of the Dirac equation for
electric neutral particles with anomalous electric and magnetic moments. Using
the algebraic method of separation of variables, the Dirac equation is
separated in cartesian, cylindrical and spherical coordinates, and exact
solutions are obtained in terms of special functions.Comment: 20pp, IVIC-CFLE-93/02 (this is a version without Tex problems, the
first version was corrupted
Structure of 5-nitro-2-tosylaminobenzaldehyde di(morpholin-4-yl)aminal Complex with Carbon Tetrachloride
The 5-nitro-2-tosylaminobenzaldehyde di(morpholin-4-yl)aminal forms a stable complex with carbon tetrachloride in the crystal phase. X-ray structural study of this complex indicates an essentially shortened intermolecular contact of 2.89 Å between the oxygen atom of the nitro group and one of the chlorine atom of the CCI4 molecule. Quantum-chemical calculations by semiempirical AMI method showed that the formation of such complex did not cause considerable decrease of system energy or change of charge distribution in molecules. It was supposed that this associate has van der Waals character
Exact solution of the two-dimensional Dirac oscillator
In the present article we have found the complete energy spectrum and the
corresponding eigenfunctions of the Dirac oscillator in two spatial dimensions.
We show that the energy spectrum depends on the spin of the Dirac particle.Comment: revtex, 6pp. IVIC-CFLE 93/0
The Angular Momentum Operator in the Dirac Equation
The Dirac equation in spherically symmetric fields is separated in two
different tetrad frames. One is the standard cartesian (fixed) frame and the
second one is the diagonal (rotating) frame. After separating variables in the
Dirac equation in spherical coordinates, and solving the corresponding
eingenvalues equations associated with the angular operators, we obtain that
the spinor solution in the rotating frame can be expressed in terms of Jacobi
polynomials, and it is related to the standard spherical harmonics, which are
the basis solution of the angular momentum in the Cartesian tetrad, by a
similarity transformation.Comment: 13 pages,CPT-94/P.3027,late
Synthesis and structure of N-alkoxyhydrazines and N-alkoxy-N',N',N'-trialkylhydrazinium salts
New types of 1,1,1-trialkyl-2-alkoxyhydrazinium chlorides and N-alkoxyhydrazines were obtained by reactions of N-chloro-N-alkoxyureas with trimethylamine or 1,4-diaza[2.2.2]bicyclooctane and by reactions of methyl N chloro-N-methoxycarbamate with potassium salt of N-acetylbenzenesulfonylamide. The XRD studies of N,N' bis(methoxycarbonyl)-N,N'-dimethoxyhydrazine, N'-methoxy-N'‑methoxycarbonyl-N-acetylbenzenesulfonylhydrazide and 1,1,1-trimethyl-2-methoxyhydrazinium perchlorate revealed the pyramidal configuration of the central nitrogen atoms in O–N–N geminal system, unusual elongation of N–N+ bond and shortening of N–OMe bond in 1,1,1-trimethyl-2-methoxyhydrazinium perchlorate
New approach to N,N-dialkoxy-N'-arylureas and N,N-dialkoxycarbamates
Methanolysis of N-chloro-N-alkoxy-N'-arylureas in the presence of silver trifluoroacetate gives the corresponding N,N-dialkoxy-N'‑arylureas, whereas N-chloro-N-alkoxycarbamates react with alcohols in the presence of silver trifluoroacetate to afford N,N-dialkoxycarbamates
Relationship between various pathways of cellular death at distinct stages of ontogenesis in normal state and systemic diseases of connective tissue
The aim of our research was to reveal quantitative ratios existing between the pathways of cellular death in normal state, as well as in immunocomplex pathology. The proportion of different pathways of cell death (autophagy, apoptosis, necrosis) in autoimmune (systemic connective tissue diseases (SDCT) – rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and systemic scleroderma (SSD) is a subject of age-related changes. On the one hand, aging process can be considered a genetically determined overall decrease in adaptive potential of the body, and a systemic age-related chronic inflammatory response, with a pronounced cytokine proinflammatory shift. On the other hand, a polygenic decrease in energy and information capacity of the cells, represent the basis of multisystem and multiorgan functional and metabolic disorders in SDCT.Blood plasma samples were analyzed in the patients of two age groups. The first group consisted of 10 SLE cases (4 men and 6 women, average age 43.8 years), 13 patients with RA (5 men and 8 women, average age 45.6 years), 7 SSD (women, average age 35.8 years), and 10 healthy donors (6 men and 4 women, average age 40.7 years). The second age group consisted of 9 SLE cases (2 men and 7 women, average age 69.8 years), 10 patients with RA (5 men and 5 women, average age 65.6 years), 5 patients with SSD (women, average age 65.7 years) and 12 healthy donors (normal biological aging – 7 men and 5 women, average age 64.7 years). The data presented in this paper were obtained with informed consent of the patients. When carrying out biomedical research, we followed internationally recognized ethical standards of the Helsinki Declaration (International Medical Association, 1996, revision 2013). The proportion of various cell death types (autophagy, apoptosis, necrosis) in autoimmune disorders (systemic diseases of connective tissue, SDCT), i.e., rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and systemic scleroderma (SSD) proved to be subject to age-dependent changes. Close interaction were revealed between the ways of cellular death in SDCT (most pronounced in SLE), correlating with age changes and clinical manifestations of autoimmune process. In SDCT, the affected tissues exhibit all types of cellular death, however, degree of their expression depends on the disease nosology. Upon systemic diffuse pathology of connective tissue, autophagy (especially in case of SLE and RA) is directly involved in development of immune response and inflammatory process.In normal biological aging, like as in SDCT, one may observe a sharply increased activity of the metabolic trigger – AMP-activated protein kinase (AMPK), a sensor of intracellular energy, along with shifted acid-base equilibrium. The quantity of active oxygen radicals increases, oxidoreductive potential of the cells is changed, with activation of cellular destruction components. Activity of cytokine system in the organism is changed causing apoptosis regulation; expression of chaperons is decreased, and the immune-oxygenase homeostasis is also displaced. Inhibition of genetically determined process of death of cells (apoptosis) comprises the basis for development of autoimmune diseases. Transition of late apoptosis into secondary necrosis is accompanied by decrease of antioxidant protection and development of autoimmune pathology. The chaperon-mediated induction of immune response as the signaling mechanism of autophagy, being evolutionarily fixed in mammals only, may be the common central link and “the molecular switch” causing both development of autoimmune diseases of connective tissue, and aging processes
The properties and structure of N-chloro-N-methoxy-4-nitrobenzamide
The XRD study of N-chloro-N-methoxy-4-nitrobenzamide revealed the high pyramidality degree of its amide nitrogen atom in O–N–Cl moiety. N-Chloro-N-methoxy-4-nitrobenzamide reacts with AcONa in MeCN selectively forming N-acetoxy-N-methoxy-4-nitrobenzamide, whereas its methanolysis in the presence of AcONa yields N,N' bis(4-nitrobenzoyl)-N,N'-dimethoxyhydrazine
Pyramidal amide nitrogen in N-acyloxy-N-alkoxyureas and N-acyloxy-N-alkoxycarbamates
The XRD studies of N-acyloxy-N-alkoxyamides 1, 2 have revealed a highly pyramidal configuration of amide nitrogen in the O–N–O group
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