187 research outputs found

    Stimulated emission in organic films for longitudinal pulsed pumping

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    In this paper the generation of Rhodamine 800 (Rh 800) in ethanol and also mixtures of Pirrometen 597 and Rh 800 in transversal pumping and longitudinal types is investigated. TGF PMMA, Rh 800 solvents with copolymer PMMA IBMA films generation characteristics are obtained. Research was conducted at exaltation by the pulse laser wavelength of excitement is 532 nm, duration of an impulse is 10 ns, pumping power density is 13 MW/cm2). Films doped with the dye were created by a watering method (concentration of days = 5 × 10 - 4 moll/l). Thickness of films was measured using the optical profilometer KLA – Tencor MicroXam 100 and was obtained 5.8 microns

    Pathogenic and therapeutic role of bile acids at reflux-gastritis

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    The aim of review. To present data on pathogenic significance of bile acids for upper regions of gastrointestinal tract (GIT) and to describe medical properties ursodeoxycholic acid (UDCA) at reflux-gastritis.Summary. Reflux-gastritis is chemical type gastritis, morphologically manifested by foveolar hyperplasia, edema, proliferation of smooth-muscle fibres of lamina propria, insignificant chronic inflammation. There is evidences of relation of intestinal metaplasia to duodenogastric reflux (DGR). Bile acids at certain conditions possess damage effect on mucosa of the stomach and all GIT. They can increase endocellular concentration of calcium which is responsible for toxic effects of bile acids as a secondary messenger. Increase of endocellular calcium stimulates secretion of pepsinogen and acid production in the stomach,  that in the case of decreased cytoprotective factors by DGR can cause changes mucosal injury. According to the modern point of view bile acids are associated with a lot of neoplasms of digestive organs, including esophageal, stomach, small intestine, liver, pancreas and colorectal cancer. Exposition of bile acids results in formation of active forms of oxygen and nitrogen, damage of DNA, mutagenicity, induction of apoptosis in short-term prospect and resistance to apoptosis in long-term prospect. Gastric remnant gastritis is consideres to be a premalignant disease, thus bile acids play essential role in carcinogenesis. UDCA possesses choleretic effect and ability to displace toxic hydrophobic bile acids. It protects from oxydative stress, stabilizes cell membranes and inhibits apoptosis. At reflux-gastritis UDCA relieves clinical symptoms, improves of state of mucosa of the stomach and esophagus, and possess series of cytoprotective properties.Conclusion. Prescription of UDCA is pathogenicly proved in patients with reflux-gastritis and gastroesopha geal reflux disease (GERD) with non-acidic refluxes. Cytoprotective and antiapoptotic effects of UDCA at reflux-gastritis are especially significant from the point of view of smoothing cancerogenic potential of bile acids

    Inflammation, impaired motor function and visceral hypersensitivity: the main mechanisms of functional disorders of the gastrointestinal tract (materials of the Expert Council and literature review)

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    Aim. To review the main mechanisms of functional disorders of the gastrointestinal tract and to present the materials of an Expert Council, which was held on 10 December 2021 in Moscow.Key points. The pathogenesis of the most common functional diseases of the gastrointestinal tract — functional dyspepsia (FD) and irritable bowel syndrome (IBS) is multifactorial and includes motor disorders of various parts of the gastrointestinal tract, visceral hypersensitivity, changes in the intestinal microbiome, impairment of the permeability of the protective barrier, low-grade inflammation of the gastrointestinal mucosa, etc. This often leads to the prescription of a complex of various medications to such patients, which increases the risk of undesirable drug interactions and side effects. Multitargeted therapy involves the use of drugs that simultaneously affect different pathogenetic links. One of these drugs is Iberogast®, which normalizes gastrointestinal motility and visceral sensitivity, has an anti-inflammatory action and is highly effective in treatment of FD and IBS.Conclusion. In the treatment of functional gastrointestinal diseases characterized by multifactorial pathogenesis, preference should be given to multi-targeted therapy with the use of drugs that have an effect on its various links

    First observation of proton reflection from bent crystals

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    We recently suggested using short bent crystals as primary collimators in a two stage cleaning system for hadron colliders, with the aim of providing larger impact parameters in the secondary bulk absorber, through coherent beam-halo deflection [1]. Tests with crystals a few mm long, performed with 70 GeV proton beams at IEHP in Protvino, showed a channeling efficiency exceeding 85 %. We also observed disturbing phenomena such as dechannelling at large impact angle, insufficient bending induced by volume capture inside the crystal, multiple scattering of non-channeled protons and, for the first time, a proton flux reflected by the crystalline planes. Indeed, protons with a tangent path to the curved planes somewhere inside the crystal itself are deflected in the opposite direction with respect to the channeled particles, with an angle almost twice as large as the critical angle. This effect, up to now only predicted by computer simulations [2], produces a flux of particles in the wrong direction with respect to the absorber, which may hamper the collimation efficiency if neglected

    ANTIBACTERIAL ACTIVITY OF CARBON-CONTAINING COATINGS

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    The surface biological effect of nanocarbon coatings, which can be used in the clinical practice of implantology due to their unique properties, has been studied
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