121 research outputs found

    Effect of electrolysis regimes on the structure and properties of coatings on aluminum alloys formed by anode-cathode microarc oxidation

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    Наведено результати дослідження фазового складу і властивостей МДО-покриттів на алюмінієвих сплавах. Покриття були одержані в лужно-селікатному електроліті на змінному сінусоідальному струмі і в імпульсному режимі струму. Показано, що підвищена щільність мікророзрядів при імпульсної технології збільшує сумарну енергію, що виділяється в них. Це обумовлює підвищення швидкості зростання оксидного покриття і ймовірність утворення α-Al₂O₃ фази. Одержані при мікроплазмове оксидуванні в імпульсному струмовому режимі покриття мають високу твердість і електричну міцніст

    Generation of coherent terahertz pulses in Ruby at room temperature

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    We have shown that a coherently driven solid state medium can potentially produce strong controllable short pulses of THz radiation. The high efficiency of the technique is based on excitation of maximal THz coherence by applying resonant optical pulses to the medium. The excited coherence in the medium is connected to macroscopic polarization coupled to THz radiation. We have performed detailed simulations by solving the coupled density matrix and Maxwell equations. By using a simple VV-type energy scheme for ruby, we have demonstrated that the energy of generated THz pulses ranges from hundreds of pico-Joules to nano-Joules at room temperature and micro-Joules at liquid helium temperature, with pulse durations from picoseconds to tens of nanoseconds. We have also suggested a coherent ruby source that lases on two optical wavelengths and simultaneously generates THz radiation. We discussed also possibilities of extension of the technique to different solid-state materials

    Identification of electrofacies on the basis of well logging to determine sedimentation environment of horizon JK[2] in Em-Egovskoe field (Western Siberia)

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    Well logging results are one of the ways to study the buried terrigenous rocks genesis. To ensure the most objective characterization of the rock and identification of electrofacies it is necessary to use a complex geological and geophysical survey. The comprehensive investigations of environmental conditions based on well logging have been performed for the horizon JK[2] of Tumenskoe formation in Em-Egovskoe area, Krasnoleninskoe field (Western Siberia). The defined electrofacies were compared with the results of earlier conducted granulometric and mineralogical analyses. The totality of research provided for a conclusion that the investigated sediments of horizon JK2 had been formed within the destructive tidal delta. Thus, objective facies prediction can only be ensured by analyzing core and well logging data comprehensively

    DNA fragments binding CTCF in vitro and in vivo are capable of blocking enhancer activity

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    <p>Abstract</p> <p>Background</p> <p>Earlier we identified ten 100-300-bp long CTCF-binding DNA fragments selected earlier from a 1-Mb human chromosome 19 region. Here the positive-negative selection technique was used to check the ability of CTCF-binding human genomic fragments to block enhancer-promoter interaction when inserted into the genome.</p> <p>Results</p> <p>Ten CTCF-binding DNA fragments were inserted between the CMV enhancer and CMV minimal promoter driving the herpes simplex virus thymidine kinase (HSV<it>-tk</it>) gene in a vector expressing also the <it>neo</it><sup>R </sup>gene under a separate promoter. The constructs were then integrated into the genome of CHO cells, and the cells resistant to neomycin and ganciclovir (positive-negative selection) were picked up, and their DNAs were PCR analyzed to confirm the presence of the fragments between the enhancer and promoter in both orientations.</p> <p>Conclusions</p> <p>We demonstrated that all sequences identified by their CTCF binding both <it>in vitro </it>and <it>in vivo </it>had enhancer-blocking activity when inserted between the CMV minimal promoter and enhancer in stably transfected CHO cells.</p

    GABRIELA : a new detector array for gamma-ray and conversion electron spectroscopy of transfermium elements

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    With the aid of the Geant4 Monte Carlo simulation package a new detection system has been designed for the focal plane of the recoil separator VASSILISSA situated at the Flerov Laboratory of Nuclear Reactions, JINR, Dubna. GABRIELA (Gamma Alpha Beta Recoil Investigations with the Electromagnetic Analyser VASSILISSA) has been optimised to detect the arrival of reaction products and their subsequent radioactive decays involving the emission of alpha- and beta-particles, fission fragments, gamma- and X-rays, and conversion electrons. The new detector system is described and the results of the first commissioning experiments are presented.Comment: 24 pages, Submitted to NIM

    Standard and increased canakinumab dosing to quiet macrophage activation syndrome in children with systemic juvenile idiopathic arthritis

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    ObjectiveMacrophage activation syndrome (MAS) is a life-threatening, potentially fatal condition associated with systemic juvenile idiopathic arthritis (sJIA). Interleukin-1 (IL-1) is a key cytokine in the pathogenesis of sJIA MAS. Many cases of MAS are medically refractory to traditional doses of biologic cytokine inhibitors and may require increased dosing. When MAS occurs in the setting of sJIA treated with the IL-1 receptor antagonist (IL-1Ra), anakinra, increased anakinra dosing may be beneficial. Increased dosing of another IL-1 inhibitor, canakinumab, a monoclonal antibody to IL-1β, has not been reported to treat refractory MAS in the setting of sJIA.MethodsRetrospective data collection extracted from the electronic medical record focused on canakinumab usage and dosing in 8 children with sJIA who developed MAS at a single academic center from 2011 to 2020.ResultsEight sJIA children (five girls) with median age 8.5 years (range, 0.9–14.2 years) were included in the present study. Five children developed MAS at disease onset and three during ongoing canakinumab therapy. MAS resolved in all eight children with canakinumab treatment. When the canakinumab dosing was insufficient or MAS developed during canakinumab therapy, the dosing was temporally up-titrated (four patients, maximum 300 mg per dose) without observed side effects.ConclusionThis report provides evidence for the efficacy and safety of short-term increased doses (2–3-times normal) of canakinumab in treating sJIA associated MAS. Further study of the efficacy and safety of increased doses of canakinumab for treatment of MAS in children with sJIA is warranted

    Imaging oxygenation of human tumours

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    Tumour hypoxia represents a significant challenge to the curability of human tumours leading to treatment resistance and enhanced tumour progression. Tumour hypoxia can be detected by non-invasive and invasive techniques but the inter-relationships between these remains largely undefined. (18)F-MISO and Cu-ATSM-PET, and BOLD-MRI are the lead contenders for human application based on their non-invasive nature, ease of use and robustness, measurement of hypoxia status, validity, ability to demonstrate heterogeneity and general availability, these techniques are the primary focus of this review. We discuss where developments are required for hypoxia imaging to become clinically useful and explore potential new uses for hypoxia imaging techniques including biological conformal radiotherapy

    Defining criteria for disease activity states in systemic juvenile idiopathic arthritis based on the systemic Juvenile Arthritis Disease Activity Score

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    Objective To develop and validate cutoff values in the systemic Juvenile Arthritis Disease Activity Score 10 (sJADAS10) that distinguish the states of inactive disease (ID), minimal disease activity (MiDA), moderate disease activity (MoDA), and high disease activity (HDA) in children with systemic juvenile idiopathic arthritis (sJIA), based on subjective disease state assessment by the treating pediatric rheumatologist. Methods The cutoffs definition cohort was composed of 400 patients enrolled at 30 pediatric rheumatology centers in 11 countries. Using the subjective physician rating as an external criterion, 6 methods were applied to identify the cutoffs: mapping, calculation of percentiles of cumulative score distribution, Youden index, 90% specificity, maximum agreement, and ROC curve analysis. Sixty percent of the patients were assigned to the definition cohort and 40% to the validation cohort. Cutoff validation was conducted by assessing discriminative ability. Results The sJADAS10 cutoffs that separated ID from MiDA, MiDA from MoDA, and MoDA from HDA were ≤ 2.9, ≤ 10, and > 20.6. The cutoffs discriminated strongly among different levels of pain, between patients with or without morning stiffness, and between patients whose parents judged their disease status as remission or persistent activity/flare or were satisfied or not satisfied with current illness outcome. Conclusion The sJADAS cutoffs revealed good metrologic properties in both definition and validation cohorts, and are therefore suitable for use in clinical trials and routine practice

    Real-Time Imaging of HIF-1α Stabilization and Degradation

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    HIF-1α is overexpressed in many human cancers compared to normal tissues due to the interaction of a multiplicity of factors and pathways that reflect specific genetic alterations and extracellular stimuli. We developed two HIF-1α chimeric reporter systems, HIF-1α/FLuc and HIF-1α(ΔODDD)/FLuc, to investigate the tightly controlled level of HIF-1α protein in normal (NIH3T3 and HEK293) and glioma (U87) cells. These reporter systems provided an opportunity to investigate the degradation of HIF-1α in different cell lines, both in culture and in xenografts. Using immunofluorescence microscopy, we observed different patterns of subcellular localization of HIF-1α/FLuc fusion protein between normal cells and cancer cells; similar differences were observed for HIF-1α in non-transduced, wild-type cells. A dynamic cytoplasmic-nuclear exchange of the fusion protein and HIF-1α was observed in NIH3T3 and HEK293 cells under different conditions (normoxia, CoCl2 treatment and hypoxia). In contrast, U87 cells showed a more persistent nuclear localization pattern that was less affected by different growing conditions. Employing a kinetic model for protein degradation, we were able to distinguish two components of HIF-1α/FLuc protein degradation and quantify the half-life of HIF-1α fusion proteins. The rapid clearance component (t1/2 ∼4–6 min) was abolished by the hypoxia-mimetic CoCl2, MG132 treatment and deletion of ODD domain, and reflects the oxygen/VHL-dependent degradation pathway. The slow clearance component (t1/2 ∼200 min) is consistent with other unidentified non-oxygen/VHL-dependent degradation pathways. Overall, the continuous bioluminescence readout of HIF-1α/FLuc stabilization in vitro and in vivo will facilitate the development and validation of therapeutics that affect the stability and accumulation of HIF-1α
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