611 research outputs found

    Electrically neutral Dirac particles in the presence of external fields: exact solutions

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    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

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    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

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    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

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    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

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    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

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    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

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    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

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    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

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    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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