3,954 research outputs found

    High-Precision Heating Stage for the Bio Endstation of the Microprobe

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    Demand driven salt clean-up in a molten salt fast reactor – Defining a priority list

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    <div><p>The PUREX technology based on aqueous processes is currently the leading reprocessing technology in nuclear energy systems. It seems to be the most developed and established process for light water reactor fuel and the use of solid fuel. However, demand driven development of the nuclear system opens the way to liquid fuelled reactors, and disruptive technology development through the application of an integrated fuel cycle with a direct link to reactor operation. The possibilities of this new concept for innovative reprocessing technology development are analysed, the boundary conditions are discussed, and the economic as well as the neutron physical optimization parameters of the process are elucidated. Reactor physical knowledge of the influence of different elements on the neutron economy of the reactor is required. Using an innovative study approach, an element priority list for the salt clean-up is developed, which indicates that separation of Neodymium and Caesium is desirable, as they contribute almost 50% to the loss of criticality. Separating Zirconium and Samarium in addition from the fuel salt would remove nearly 80% of the loss of criticality due to fission products. The theoretical study is followed by a qualitative discussion of the different, demand driven optimization strategies which could satisfy the conflicting interests of sustainable reactor operation, efficient chemical processing for the salt clean-up, and the related economic as well as chemical engineering consequences. A new, innovative approach of balancing the throughput through salt processing based on a low number of separation process steps is developed. Next steps for the development of an economically viable salt clean-up process are identified.</p></div

    Estimating rainfall erosivity from daily precipitation records: a comparison among methods using data from the Ebro Basin (NE Spain)

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    Among the major factors controlling soil erosion, as vegetation cover or soil erodibility, rainfall erosivity has a paramount importance since it is difficult to predict and control by humans. Accurate estimation of rainfall erosivity requires continuous rainfall data; however, such data rarely demonstrate good spatial and temporal coverage. Daily weather records are now commonly available, providing good coverage that better represents rainfall intensity behavior than do more aggregated rainfall data. In the present study annual rainfall erosivity was estimated from daily rainfall records, and compared to data obtained employing the RUSLE R factor procedure. A spatially-dense precipitation database of high temporal resolution (15 min) was used. Two methodologies were applied: (i) daily rainfall erosivity estimated using several parametric models, and, (ii) annual rainfall erosivity estimated by regression-based techniques employing several intensity precipitation indices and the modified Fournier index. To determine the accuracy of estimates, several goodness-of-fit and error statistics were computed in addition to a spatial distribution comparison. The daily rainfall erosivity models accurately predicted annual rainfall erosivity. Parametric models with few combined parameters and a periodic function simulating intra-annual rainfall behavior provided the best results. Where daily rainfall records were not available, good estimates of annual rainfall erosivity were also obtained using regression-based techniques based on 5-day maximum precipitation events, the maximum wet spell duration, and the ratio between the lengths of average wet and dry spells. Inherent limitations remain in the use of daily weather records for estimating rainfall erosivity. Future research should focus on incorporating measures of natural rainfall properties of the particular region, including kinetic energy and intensity, and their effects on the soil.We thank the Ebro River Hydrographical Confederation (Confederación Hidrográfica del Ebro; CHE) for providing the data used in this study. The research of M.A. was supported by a JAE-Predoc Research Grant from the Spanish National Research Council (Consejo Superior de Investigaciones Científicas; CSIC).Peer reviewe

    Prior Debt and the Cost of Going Public

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    Previous studies find that firms with prior debt, particularly publicly rated, have lower information asymmetry and experience a lower opportunity cost of going public, as measured by underpricing. Subsequent research suggests that underpricing may be an inaccurate measure of indirect issuance costs. Thus, we replicate and extend existing studies to examine whether previously issued debt reduces the true opportunity cost of issuance. We find that private debt issues have little effect; however, firms with public debt (particularly rated) have both significantly lower levels of underpricing and lower issuance opportunity costs, as well as narrower filing ranges and smaller price revisions, all of which are consistent with reduced asymmetry. We find, however, that matching issues by firm size eliminates the significant relations. Thus, we conclude that although prior public debt appears to reduce information asymmetries, it is more likely a reflection of the underlying characteristics of firms with these existing securities

    Branching ratio measurements of BsB_s decays

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    We have just entered an era of precision measurements for

    The use of ketamine in electroconvulsive therapy

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    Summary In recent years, data on the possibility of rapid clinical improvement after administration of ketamine in patients diagnosed with depression have been published more frequently. Ketamine, used as an anaesthetic during ECT procedures, despite earlier concerns, has both: a good safety profile and minimal effect on seizure threshold, which is used in cases of non-response to ECT. Postulated action of ketamine causes a rapid resolution of depressive symptoms and raised hopes to accelerate therapeutic effect of ECT in patients with severe depression, but studies provide contradictory data pointing to brevity of the observed effect. Studies examining the use of ketamine combined with other anaesthetic drugs emphasised not only its antidepressant effect, but also improvement in hemodynamic parameters during ECT treatment. The aim of this work on one hand is to make psychiatrists aware that the role of anaesthesiologist at ECT is not limited to anaesthetise a patient and provide muscle relaxation, and, on the other hand, to make anaesthesiologists aware that drugs they use have a significant effect on seizure parameters and indirectly on the effectiveness of ECT. Due to small size of studied populations the issue of antidepressant efficacy of ketamine requires further exploration

    Multiple Cytochrome P450 Isozymes in Murine Skin: Induction of P450 1A, 2B, 2E, and 3A by Dexamethasone

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    Cytochrome P450s (P450s) are a supergene family of enzymes responsible for the metabolism of a wide range of endogenous and foreign compounds. P450 isozymes possess overlapping substrate specificity. Systemic administration of dexamethasone, a widely used topical agent in dermatologic practice, to animals is known to result in the induction of multiple P450 isozymes in liver. In this study the effect of topical application of dexamethasone to mice on P450-dependent monooxygenase activities, expression of P450 isozymes, and P450 mRNA levels in skin was assessed. The treatment of mice with dexamethasone resulted in significant induction of 7-ethoxyresorufin O-deethylase (2.3 times), 7-pentoxyresorufin O-depentylase (19.2 times), para-nitrophenol hydroxylase (7.5 times), and erythromycin N-demethylase (2.2 times) activities; the monooxygenases catalyzed preferentially by P450 isozymes 1A1, 2B1, 2E1, and 3A, respectively. Immunoblot analysis of cutaneous microsomes, employing antibodies directed against purified P450s 1A1/2, 2B1/2, 2E1, and 3A, showed that dexamethasone treatment results in an increased immunoreactivity (1.8 – 13.9 times). In immunohistochemical staining of skin with antibody against P4502B1/2, topical application of dexamethasone resulted in an increased reactivity towards microsomal protein in the suprabasal layer of the epidermis and with the cells of the hair follicles. Whereas constitutive expression of mRNAs for CYP1A1 and CYP2E1 was evident in murine skin, any change in the levels of these mRNAs following treatment with dexamethasone was not apparent. The results of our study indicate that the application of dexamethasone to murine skin results in the induction of several families of P450 isozymes, suggesting that murine skin contains multiple inducible P450 isozymes capable of participating in the metabolism of a wide range of xenobiotics and endogenous compounds

    ВДОСКОНАЛЕННЯ УПРАВЛІННЯ ФІНАНСУВАННЯМ ІННОВАЦІЙНО-ІНВЕСТИЦІЙНОЇ ДІЯЛЬНОСТІ НА ПРОМИСЛОВИХ ПІДПРИЄМСТВАХ

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    Метою статті є дослідження особливостей фінансових аспектів управління інноваційно-інвестиційною діяльністю промислових підприємств і визначення шляхів підвищення ефективності фінансування ІІДРозкрито сутність і зміст системи управління фінансуванням інноваційно-інвестиційної діяльності на промислових підприємства

    Development of Light‐Activated LXR Agonists

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    Activation of the oxysterol-sensing transcription factor liver X receptor (LXR) has been studied as a therapeutic strategy in metabolic diseases and cancer but is compromised by the side effects of LXR agonists. Local LXR activation in cancer treatment may offer an opportunity to overcome this issue suggesting potential uses of photopharmacology. We report the computer-aided development of photoswitchable LXR agonists based on the T0901317 scaffold, which is a known LXR agonist. Azologization and structure-guided structure-activity relationship evaluation enabled the design of an LXR agonist, which activated LXR with low micromolar potency in its light-induced (Z)-state and was inactive as (E)-isomer. This tool sensitized human lung cancer cells to chemotherapeutic treatment in a light-dependent manner supporting potential of locally activated LXR agonists as adjuvant cancer treatment
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