Some aspects of the theory of the propagation of nonlinear waves in unstable media

The behaviour of waves in stable and unstable media in the nonlinear regime is of considerable interest and relevance to many physical systems. New, tractable techniques are required to account for the possible interactions of dispersive, dissipative and modulational effects and their effects on the propagation of nonlinear waves. The reductive perturbation technique an asymptotic expansion in multiple time and space scales — is extended to apply to wave propagation in unstable media in both one and two dimensions. It is shown that, to lowest order, the wave amplitude satisfies a form of nonlinear Schrödinger equation and the validity of this equation is established for a much wider class of systems than was previously supposed. Explicit expressions are given for determining the complex coefficients of this equation from the coefficients of the system of equations describing the original physical system. These general methods are applied to two physical systems. A nonlinear theory of the propagation of acoustic waves in piezoelectric semiconductors is presented and an explicit solution of the relevant generalised nonlinear Schrödinger is found using a perturbation technique. This solution is found to be an envelope soliton and theoretically confirms domain propagation in piezoelectric semiconductors. A nonlinear theory of a two-stream instability in a marginally stable state is given and the wave equation is found to be a different form of the nonlinear Schrödinger equation. The nonlinear effects are found to enhance rather than suppress the instability in agreement with previously published results. A discussion is given of the stability of inhomogeneous plasma streams in mutually perpendicular electric and magnetic fields and suggestions are made for the development of a nonlinear theory of such systems using the general techniques developed

Ablacja łącza przedsionkowo-komorowego jako terapia pomostowa tachykardiomiopatii i niewydolności nerek w przebiegu migotania przedsionków z szybkim rytmem komór

We present the case of a 67 year-old woman with tachycardiomyopathy induced by atrial fibrillation with high frequency ventricular response. The patient underwent resynchronisation pacemaker implantation and atrioventricular junction ablation as a bridging therapy prior to cryoballoon pulmonary vein ostia ablation.W pracy przedstawiono przypadek 67-letniej chorej z tachykardiomiopatią w przebiegu migotania przedsionków z szybkim rytmem komór leczoną implantacją stymulatora resynchronizującego i ablacją łącza przedsionkowo-komorowego jako terapią pomostową przed krioablacją balonową ujść żył płucnych

The expansion of CD4(+)CD28(- )T cells in patients with rheumatoid arthritis

Clonal expansion of CD4(+)CD28(- )T cells is a characteristic finding in patients with rheumatoid arthritis (RA). Expanded CD4(+ )clonotypes are present in the peripheral blood, infiltrate into the joints, and persist for years. CD4(+)CD28(- )T cells are oligoclonal lymphocytes that are rare in healthy individuals but are found in high percentages in patients with chronic inflammatory diseases. The size of the peripheral blood CD4(+)CD28(- )T-cell compartment was determined in 42 patients with RA and 24 healthy subjects by two-color FACS analysis. The frequency of CD4(+)CD28(- )T cells was significantly higher in RA patients than in healthy subjects. Additionally, the number of these cells was significantly higher in patients with extra-articular manifestations and advanced joint destruction than in patients with limited joint manifestations. The results suggest that the frequency of CD4(+)CD28(- )T cells may be a marker correlating with extra-articular manifestations and joint involvement

The role of interleukin-18 in the pathogenesis of bronchial asthma and other allergic diseases and in activation of basophils and mastocytes

Interleukina 18 (IL-18) jest prozapalną cytokiną produkowaną przez szereg komórek, biorącą udział w patogenezie chorób o podłożu zapalnym jak na przykład astma atopowa. Wykazano, że IL-18 wpływa na limfocyty T, wywołując nadwrażliwość drzewa oskrzelowego oraz rozwój stanu zapalnego. Ponadto stymuluje limfocyty Th1 do wydzielania cytokin i chemokin stymulujących nacieki w drogach oddechowych i odczyn zapalny. Pobudza także mastocyty i bazofile biorące udział w odczynie atopowym. Astma atopowa jest chorobą charakteryzującą się eozynofilowymi naciekami w drogach oddechowych wraz z remodelingiem, nadmiernym wydzielaniem śluzu oraz wysokimi stężeniami IgE w surowicy. Wyniki ostatnich badań wykazały, że w patogenezie astmy rolę odgrywa także odpowiedź immunologiczna typu Th2 związana z atopią oraz rozwojem stanu zapalnego przy udziale IgE oraz prozapalnych cytokin, jak na przykład Il-18. W niniejszym opracowaniu omówiono rolę IL-18 w aktywacji mastocytów i bazofili oraz patogenezie chorób atopowych.Interleukin-18 is a proinflammatory cytokine produced by a wide range of cells and is involved in the pathogenesis of several inflammatory diseases such as atopic asthma. It was recently demonstrated that IL-18 acts on T cells to induce airway inflammation and airway hyperresponsiveness. These observations strongly indicate that IL-18 stimulates Th1 cells to produce cytokines and chemokines responsible for the airway infiltration and inflammatory responsiveness. Moreover IL-18 activates mast cells and basophils playing the important role in atopy. Atopic asthma is characterized by eosinophilic airway inflammation, remodeling, mucus hypersecretion and high serum levels of IgE. Most current data suggest that asthma drives development of a Th2 lymphocyte-predominant immune response, which is associated with atopy and IgE mediated inflammation via pathways involving the production of proinflammatory cytokines such as IL-18. Here we discuss the functional role of IL-18 in activation of mast cells and basophils and pathogenesis of allergic diseases

Deciphering the history of forest disturbance and its effects on landforms and soils : lessons from a pit-and-mound locality at Rogowa Kopa, Sudetes, SW Poland

The historical dimension of pit-and-mound topography has been studied at Mt Rogowa Kopa locality, Stołowe Mountains, SW Poland. This site represents one of the best developed regional examples of hummocky forest floor relief due to widespread tree uprooting and subsequent degradation of root plates. Through map analysis and dendrochronology the disturbance history was traced at least to the 1930s and most likely a strong wind episode from 1933 was the reason of forest calamity that resulted in nearly complete destruction of the original stand. However, the forest affected was a planted Norway spruce monoculture, introduced and managed at least till the beginning of 20th century, not a natural forest. The windthrow niche was then used by beech whose individuals preferentially chose mounds to grow, conserving hummocky microtopography. Changes in soil evolutionary pathways brought about by wind-driven disturbance include both homogenization (rejuvenation) and horizonation (differentiation). Evidence of soil rejuvenation includes decrease of organic carbon content and pH increase in the upper parts of soils developed on mounds in comparison with undisturbed references soils. Soil texture was relatively homogenized in pits and mounds. Dating of pit-and-mound microrelief by means of soil properties (organic carbon content, iron forms) was only partly successful. Although young age of pits and mounds is evident, the actual age inferred from soil properties was underestimated by a few tens of years. Evaluation of factors potentially controlling the propensity to widespread treethrow suggests that the type of forest is a far more important variable than local abiotic factors of bedrock geology, regolith characteristics, and slope inclination