432 research outputs found

    Origin of second-harmonic generation in the incommensurate phase of K2SeO4

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    We show that a ferroelectric phase transition takes place in the incommensurate phase of the K2SeO4 crystal. The ferroelectric character of the IC phase explains the second-harmonic generation observed in the corresponding temperature range.Comment: 5 pages, 1 figur

    Ablation and transmission of thin solid targets irradiated by intense extreme ultraviolet laser radiation

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    The interaction of an extreme ultraviolet (EUV) laser beam with a parylene foil was studied by experiments and simulation. A single EUV laser pulse of nanosecond duration focused to an intensity of 3 × 1010 W cm−2 perforated micrometer thick targets. The same laser pulse was simultaneously used to diagnose the interaction by a transmission measurement. A combination of 2-dimensional radiation-hydrodynamic and diffraction calculations was used to model the ablation, leading to good agreement with experiment. This theoretical approach allows predictive modelling of the interaction with matter of intense EUV beams over a broad range of parameters

    The Creation of Radiation Dominated Plasmas Using Laboratory X-Ray Lasers

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    When short wavelength extreme ultraviolet (EUV) and X-ray laser radiation is focused onto solid targets, narrow deep features are ablated and a dense, low-temperature plasma is formed. We examine the radiation dominated plasma formed by 46.9 nm laser radiation focused onto solids and show that ionisation can be significantly modified by electron degeneracy effects. Some experimental and theoretical considerations for investigating the interaction of capillary discharge lasers operating at 46.9 nm with solid and gas targets are presented

    The Observed Correlations for the Strange Multibaryon States in Systems with Λ\Lambda-Hyperon from pa Collision at Momentum of 10 Gev/cc

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    he observed well-known resonances Σ0\Sigma^0 Σ∗+\Sigma^{*+}(1385) and K∗±K^{*\pm}(892) from PDG are good tests of this method. Exotic strange multibaryon states have been observed in the effective mass spectra of: Λπ±\Lambda \pi^{\pm},Λγ\Lambda \gamma, Λp\Lambda p, Λpp\Lambda p p subsystems. The mean value of mass for Σ∗−(1385)\Sigma^{*-}(1385) resonance is shifted till mass of 1370 MeV/c2c^2 and width is two times larger than the same value from PDG. Such kind of behavior for width and invariant mass of Σ∗−(1385)\Sigma^{*-}(1385) resonance is interpreted as extensive contribution from stopped Ξ−→Λπ−\Xi^-\to\Lambda\pi^- and medium effect with invariant mass. The mean value of mass for Σ∗+(1385)\Sigma^{*+}(1385) from secondary interactions is also shifted till mass of 1370 MeV/c2c^2. The width of Σ0\Sigma^0 is ≈\approx 2 times larger than the experimental error. There are enhancement production for all observed hyperons.Comment: 4 pages, 6 figures, XXIst Rencontres de Blois "Windows on the Universe " Blois, France June 21st - June 26th, 200

    Surgical treatment of wounded persons with complicated thoracic damages

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    Objective. To improve the results of complex surgical treatment of wounded and injured persons with thoracic trauma, complicated by bronchopleural fistulas, pleural empyema and defects in the thoracic wall soft tissues, basing on introduction of the proposed procedure of vacuum therapy in combination with bronchoscopic obturation of certain bronchus. Materials and methods. Analysis of results of the complex surgical help delivery for 54 wounded persons with defects of the thoracic wall soft tissues, broncho-pleural fistulas and pleural empyema, caused by the combat thoracic trauma, on ІІІ and ІV levels of medical support while conduction of the Antiterrorist operation/Operation of the Joined Forces (the main group) and 73 injured persons with thoracic trauma of the peace period (the comparison group) in the 2014 - 2019 yrs period was conducted. Results. Improvement of complex surgical treatment of the wounded and damaged persons with thoracic trauma and defects of the thoracic wall soft tissues have permitted to reduce the complications frequency by 6.7%, and lethality - by 9.2% in the main group. Conclusion. There was proposed a procedure of vacuum therapy, ultrasound cavitation together with bronchoscopic bronchial obturation for its fistula, which have proved its efficacy in complex surgical treatment of severely wounded persons with the gun-shot thoracic damages and presence of combination of pleural empyema, bronchial fistula and defects of soft tissues

    Preventive Antibacterial Therapy in Acute Ischemic Stroke: A Randomized Controlled Trial

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    BACKGROUND: Pneumonia is a major risk factor of death after acute stroke. In a mouse model, preventive antibacterial therapy with moxifloxacin not only prevents the development of post-stroke infections, it also reduces mortality, and improves neurological outcome significantly. In this study we investigate whether this approach is effective in stroke patients. METHODS: Preventive ANtibacterial THERapy in acute Ischemic Stroke (PANTHERIS) is a randomized, double-blind, placebo-controlled trial in 80 patients with severe, non-lacunar, ischemic stroke (NIHSS>11) in the middle cerebral artery (MCA) territory. Patients received either intravenous moxifloxacin (400 mg daily) or placebo for 5 days starting within 36 hours after stroke onset. Primary endpoint was infection within 11 days. Secondary endpoints included neurological outcome, survival, development of stroke-induced immunodepression, and induction of bacterial resistance. FINDINGS: On intention-to treat analysis (79 patients), the infection rate at day 11 in the moxifloxacin treated group was 15.4% compared to 32.5% in the placebo treated group (p = 0.114). On per protocol analysis (n = 66), moxifloxacin significantly reduced infection rate from 41.9% to 17.1% (p = 0.032). Stroke associated infections were associated with a lower survival rate. In this study, neurological outcome and survival were not significantly influenced by treatment with moxifloxacin. Frequency of fluoroquinolone resistance in both treatment groups did not differ. On logistic regression analysis, treatment arm as well as the interaction between treatment arm and monocytic HLA-DR expression (a marker for immunodepression) at day 1 after stroke onset was independently and highly predictive for post-stroke infections. INTERPRETATION: PANTHERIS suggests that preventive administration of moxifloxacin is superior in reducing infections after severe non-lacunar ischemic stroke compared to placebo. In addition, the results emphasize the pivotal role of immunodepression in developing post-stroke infections. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN74386719
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