855 research outputs found

    Mode-selective toroidal mirrors for unstable resonator planar waveguide and thin slab solid-state lasers

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    Multivalued SK-contractions with respect to b-generalized pseudodistances

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    A new class of multivalued non-self-mappings, called SK-contractions with respect to b-generalized pseudodistances, is introduced and used to investigate the existence of best proximity points by using an appropriate geometric property. Some new fixed point results in b-metric spaces are also obtained. Examples are given to support the usability of our main result

    Effect of osmolytes on the activity of anti-cancer enzyme L-Asparaginase II from Erwinia chrysanthemi

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    L-asparaginase is used for the treatment of acute lymphoblastic leukaemia (ALL); however, its formulation presents drawbacks such as a lack of stability and formation of aggregates. Osmolytes are small molecules accumulated by cells in response to environmental stresses and present a protective behaviour, favouring the equilibrium of macromolecules towards the native conformation. Therefore, osmolytes are employed as excipients in pharmaceutical protein formulations. Herein, recombinant L-ASNase II from Erwinia chrysanthemi (ErA II) was analysed with respect to the effect of osmolytes on kinetic and stability of this biopharmaceutical. The aggregation profiles were analysed trough nanotracking particle analysis and dynamic light scattering. The majority of the tested osmolytes increased ErA II specific activity and stability, being more pronounced for sucrose and sorbitol, which increased almost 70% of ErA II activity. The polyol preserved total enzyme activity for 30 days while sucrose preserved 81.1 ± 5.3% total enzyme activity over this period. Each osmolyte resulted in a specific aggregation profile and the presence of sucrose or sorbitol resulted in a lower quantity of aggregates in the range of 100–300 nm. The present findings may contribute to the improvement of adjuvants in L-ASNase formulations and the optimization of other biopharmaceutical formulations.publishe

    Transverse Momentum Spectra of Pions in Particle and Nuclear Collisions and Some Ratio-Behaviours: Towards A Combinational Approach

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    The nature of transverse momentum dependence of the inclusive cross-sections for secondary pions produced in high energy hadronic(PPPP), hadronuclear(PAPA) and nuclear(AAAA) collisions has here been exhaustively investigated for a varied range of interactions in a unified way with the help of a master formula. This formula evolved from a new combination of the basic Hagedorn's model for particle(pion) production in PP scattering at ISR range of energies, a phenomenological approach proposed by Peitzmann for converting the results of NN(PP)NN(PP) reactions to those for either PAPA or AAAA collisions, and a specific form of parametrization for mass number-dependence of the nuclear cross sections. This grand combination of models(GCM) is then applied to analyse the assorted extensive data on various high energy collisions. The nature of qualitative agreement between measurements and calculations on both the inclusive cross-sections for production of pions, and some ratios of them as well, is quite satisfactory. The modest successes that we achieve here in dealing with the massive data-sets are somewhat encouraging in view of the diversity of the reactions and the very wide range of interaction energies.Comment: 19 pages, 19 figure

    Review of Microfluidic Devices and Imaging Techniques for Fluid Flow Study in Porous Geomaterials

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    Understanding transport phenomena and governing mechanisms of different physical and chemical processes in porous media has been a critical research area for decades. Correlating fluid flow behaviour at the micro-scale with macro-scale parameters, such as relative permeability and capillary pressure, is key to understanding the processes governing subsurface systems, and this in turn allows us to improve the accuracy of modelling and simulations of transport phenomena at a large scale. Over the last two decades, there have been significant developments in our understanding of pore-scale processes and modelling of complex underground systems. Microfluidic devices (micromodels) and imaging techniques, as facilitators to link experimental observations to simulation, have greatly contributed to these achievements. Although several reviews exist covering separately advances in one of these two areas, we present here a detailed review integrating recent advances and applications in both micromodels and imaging techniques. This includes a comprehensive analysis of critical aspects of fabrication techniques of micromodels, and the most recent advances such as embedding fibre optic sensors in micromodels for research applications. To complete the analysis of visualization techniques, we have thoroughly reviewed the most applicable imaging techniques in the area of geoscience and geo-energy. Moreover, the integration of microfluidic devices and imaging techniques was highlighted as appropriate. In this review, we focus particularly on four prominent yet very wide application areas, namely “fluid flow in porous media”, “flow in heterogeneous rocks and fractures”, “reactive transport, solute and colloid transport”, and finally “porous media characterization”. In summary, this review provides an in-depth analysis of micromodels and imaging techniques that can help to guide future research in the in-situ visualization of fluid flow in porous media

    Total Cross Section, Inelasticity and Multiplicity Distributions in Proton -- Proton Collisions

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    Multiparticle production in high energy proton -- proton collisions has been analysed in the frame of Strongly Correlated Quark Model (SCQM) of the hadron structure elaborated by the author. It is shown that inelasticity decreases at high energies and this effect together with the total cross section growth and the increasing with collision energy the masses of intermediate clusters result in the violation of KNO -- scaling.Comment: 21 pages, 11 figures, submitted to Yad. Fisik
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