Spectrum of classical two-dimensional Coulomb clusters.

The frequency spectrum of a system of classical charged particles interacting through a Coulomb repulsive potential and which are confined in a two-dimensional parabolic trap is studied. It is shown that, apart from the well-known center-of-mass and breathing modes, which are independent of the number of particles in the cluster, there are more "universal" modes whose frequencies depend only slightly on the number of particles. To understand these modes the spectrum of excitations as a function of the number of particles is compared with the spectrum obtained in the hydrodynamic approach. The modes are classified according to their averaged vorticity and it is shown that these "universal" modes have the smallest vorticity and follow the hydrodynamic behavior.

A quasiclassical approach to strongly correlated quantum dots in intense magnetic fields.

We present a general quasiclassical description of parabolic many-electron quantum dots in the limit of high magnetic fields. The key points of our approach are the transition to a rotating frame of reference, in order to decouple rotational and vibrational modes, as well as the recognition and inclusion of the role of potential anisotropy felt by the vibrational modes. We are able to obtain the complete wavefunction of quantum dots containing any number of electrons in the Gaussian form, and present results concerning inter-particle correlation and deformation of large quantum dots.

Structure and spectrum of two-dimensional clusters confined in a hard wall potential.

The structural and dynamical properties of two-dimensional (2D) clusters of equally charged classical particles, which are confined in an external hard wall potential, are investigated through the Monte Carlo simulation technique. The ground-state configuration is investigated as a function of the interparticle interaction (Coulomb, dipole, logarithmic, and screened Coulomb). The excitation spectrum corresponding to the ground-state configuration of the system is discussed. The eigenmodes are investigated and the corresponding divergence and rotor are calculated, which indicates the "shearlike" and "compressionlike" aspects of the different modes. Both small and large clusters are considered.

Structure and correlations in two-dimensional classical artificial atoms confined by a Coulomb potential.

The ordering of N equally charged particles (-e) moving in two dimensions and confined by a Coulomb potential, resulting from a displaced positive charge Ze is discussed. This is a classical model system for atoms. We obtain the configurations of charged particles which, depending on the value of N and Z, may result in ring structures, hexagonal-type configurations, and for N/Z approximately 1 in an inner structure of particles which is separated by an outer ring of particles. For N/Z<<1, the Hamiltonian of the parabolic confinement case is recovered. For N/Z approximately 1, the configurations are very different from those found in the case of a parabolic confinement potential. A hydrodynamic analysis is presented in order to highlight the correlations effects.

Aberrant vascularity and von Willebrand factor distribution in inflamed synovial membrane.

OBJECTIVE: Von Willebrand factor (vWF) is an adhesive glycoprotein produced and secreted constitutively by endothelial cells. vWF is released upon endothelial stimulation and/or vascular injury, and mediates adhesion and aggregation of platelets. Our aim was to quantify synovial vasculature and to evaluate vWF distribution in situ in synovial membranes in various arthritides. METHODS: Immunohistochemical staining of vWF in synovial membranes from patients with rheumatoid arthritis (RA) (N = 9), psoriatic (PsA) (N = 3), and reactive (ReA) (N = 4) arthritis, and from 6 noninflammatory controls: osteoarthritis (N = 1), chondromatosis (N = 1), meniscus lesion (N = 4). Morphometric assessments were performed with an image analyzer. RESULTS: In RA, mean number of blood vessels/mm2 in the thickened synovium was relatively low (131 +/- 57 vs control 257 +/- 115, p = 0.0137, ReA 346 +/- 83, p = 0.0002, PsA 434 +/- 157, p = 0.0127). In particular, the superficial layer, corresponding to the thickness of normal synovial membrane (i.e., 56 +/- 5 microns), was sparsely vascularized (70 +/- 37 in the superficial vs 219 +/- 104 in the deeper layer, p = 0.0047). Synovial thickening was not seen in ReA and PsA. In accordance with its constitutive metabolism, vWF was found in the endothelial cells, inside the blood vessels, and in the subendothelium. In addition, RA was characterized by weak endothelial immunoreactivity and perivascular vWF. In ReA, perivascular vWF staining was visible in areas of inflammatory cell infiltrates. CONCLUSION: Morphometric findings indicate decreased vascularization of the superficial synovial membrane in RA. Second, vWF may play a role in the inflammatory/reparative responses in synovium in RA and ReA, which were characterized by vascular stimulation/injury and abnormal vWF distribution.

[Assessment of the possibility of using the photodynamic effect in rheumatology]. / Otsenka vozmozhnosti ispol'zovaniia fotodinamicheskogo éffekta v revmatologii.

Results of the analysis of a number of parameters which determine the efficiency of using the photodynamic action for treating rheumatoid arthritis are reported. The investigations are based on determining the character of sensitizer stabilization in the joint tissue and evaluating its stability. As the sensitizer chlorin e6 was chosen. We have established the fact of contrast accumulation of chlorin e6 in the synovial membrane and cartilage, developed the system of intrajoint introduction of the pigment, studied the kinetics of sensitizer destruction under irradiation.

[A new chondroprotector--polyvinylpyrrolidone for treating osteoarthrosis patients]. / Novyi khondroprotektor--polivinilpirrolidon dlia lecheniia bol'nykh osteoartrozom.

The authors demonstrate the role of chondroprotector therapy in the management of patients with osteoarthrosis (OA). They suggest the use of the polymeric drug polyvinylpyrrolidone as artificial synovial fluid. The drug is administered intra-articularly and is capable of replacing pathological synovial fluid. It has been established that 10 and 20% polyvinylpyrrolidone solutions possess high viscosity and low compressibility, they are isolated from the articular cavity for 6 to 7 days and manifest antiarthrosis action in chondrocytic cultures. The short- and long-terms results of the clinical trials of polyvinylpyrrolidone solutions allow recommending them for the treatment of OA.

[Levels of the C 4 component of the complement, lactoferrin and leukocytic thermostabile alpha glycoprotein during the treatment of patients with systemic rheumatic diseases]. / Dinamika soderzhaniia C4-komponenta komplementa, laktoferrina i leikotsitarnogo termostabi'lnogo alpha-glikoproteina v protsesse lecheniia bo'lnykh revmaticheskimi zabolevaniiami.

The authors studied the dynamics of C4-component of complement (C4), lactoferrin (LF), leukocytic thermostable alpha-glycoprotein (LT alpha G) in the blood serum of 54 patients with rheumatoid arthritis, 32 patients with systemic lupus erythematosus, 8 patients with systemic vasculitis under the effect of hemosorption (HS), enterosorption (ES) and also immunosuppressants (IS). In severe forms of systemic rheumatic diseases the blood serum exhibits a decreased content of C4 but an elevated level of LF and LT alpha G. It has been established that HS is more active than ES or IS, and it influences the mechanisms of humoral immunity. This finds its expression in normalization of C4 level. The favourable clinical effect of HS correlates with a decrease in the level of LF and LT alpha G in the blood serum of patients during treatment.

[Clinico-immunologic analysis of sorption methods of treatment of rheumatoid arthritis and systemic lupus erythematosus]. / Klinicho-immunologicheskii analiz sorbtsionnykh metodov lecheniia revmatoidnogo artrita i sistemnoi krasnoi volchanki.

The paper is concerned with the results of the application of the sorption methods for the treatment of patients with rheumatoid arthritis and systemic lupus erythematosus. The authors show the advisability of the use of the above methods for different variants of the disease course, define the time of the treatment and complications common to the sorption methods of the treatment. The results of the treatment by hemoperfusion and enterosorption are compared with the results of the patients' treatment with immunodepressants. A study was made of the action of the sorption methods and immunodepressants on the blood content of the main autoantigens and autoantibodies capable of participation in the forming of the immune complexes. The concentration and the qualitative composition of the circulating immune complexes were studied in the course of the treatment.

[Efficacy of polyvinylpyrrolidone solutions of various concentrations in patients with rheumatic diseases of the joints]. / Izuchenie éffektivnosti rastvorov polivinilpirrolidona razlichnykh kontsentratsii u bol'nykh s revmaticheskimi zabolevaniiami sustavov.

Twenty-six experimental animals, 93 patients with osteoarthrosis (OA) and 30 patients with rheumatoid arthritis (RA) were examined. Intraarticular injection of both 15% and 20% polyvinylpyrrolidone (PVP) solutions suppressed the development of experimental arthrosis in rabbits, which manifested in a decrease of the degenerative changes in the cartilaginous tissue of the joints. The clinical examination has demonstrated that the use of different concentrations of PVP produces an equally marked effect in OA. In the group of RA and OA patients given placebo the time-course of changes in the clinical data was pronounced less powerfully. PVP turned out to be effective in secondary synovitis, to influence the immunologic responses occurring in synovitis, and to exert a beneficial action on the rheological properties of the synovial fluid. The drug is completely eliminated from the articular cavity and the body during 5 days.

[Quantitative assessment of the status of patients with rheumatic diseases]. / Kolichestvennaia otsenka sostoianiia bol'nykh nekotorymi revmaticheskimi zabolevaniiami.

A system of operative quantitative assessment of the status of patients with rheumatoid arthritis (RA), osteoarthrosis (OA), systemic lupus erythematosus (SLE) and systemic scleroderma (SSD) was developed using a mathematical model of discriminant analysis. Data contained in case histories of 120 patients with RA, 112 with OA, 106 with SLE and 63 with SSD were used to determine discriminant coefficients of linear discriminant equations of some functional systems: locomotor, cardiovascular, respiratory, renal, digestive, nervous, skin and subcutaneous fat, immunological as well as laboratory findings on disease standing. Knowing discriminant coefficients, one can determine an index in any values of functional indicators that characterize the status of one or another system in any phase of the treatment of a patient. The system can be used in practice in a rheumatological hospital using CM-1600 minicomputer.

[Cyclic AMP level in T- and B lymphocytes in patients with rheumatoid arthritis and systemic lupus erythematosus]. / Uroven' TsAMP v T- i B-limfotsitakh krovi bol'nykh revmatoidnym artritom i sistemnoi krasnoi volchankoi.

The content of cAMP in blood T and B lymphocytes was measured in 30 patients with rheumatoid arthritis (RA), 10 patients with systemic lupus erythematosus (SLE) and 28 donors. A statistically significant increase in the cAMP content in T lymphocytes of RA and SLE patients was established. On the contrary, in B lymphocytes of blood of RA patients and of SLE patients, in particular, the cAMP content was below normal. In female patients with RA, the cAMP content in T lymphocytes was appreciably higher than in male patients.