29 research outputs found

    Continuous laser hardening with induction pre-heating

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    A novel way of continuous surface hardening of steel bodies by a laser beam is modeled. This heat treatment is supplemented with pre-heating of the hardened parts by a classic inductor in order to reduce the temperature gradients and subsequent mechanical stresses in the processed material. The mathematical model of the process is solved numerically in 3D and the solution respects all important nonlinearities (a saturation curve of the hardened steel and temperature dependences of its physical properties). The methodology is illustrated with a typical example, whose results are presented and discussed

    31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

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    Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

    Laser hardening variables prediction by mathematical model

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    The paper deals with modeling of the laser hardening with the aim to anticipate the process of hardening and estimate the properties of the hardened body without expensive experiments

    Studie integrálního uspořádání magnetohydrodynamického čerpadla pro transport roztavených kovů či solí

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    The paper deals with one of the fundamental possibilities of improving magnetohydrodynamic (MHD) pumps based on the integration of effects of elementary MHD minipumps distributed along the pipe through which they transport the considered liquid. The crucial point of the work consists in computer modeling of this integral arrangement (system of minipumps) and presentation of the results that demonstrate their advantages–reduction of electric currents flowing through the minipumps and consequent reduction of the total ohmic losses in the system

    Proposal of induction shrink fit between disk and shaft

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    A complete proposal of induction shrink fit between a disk and shaft is presented. The proposal consists of two parts. First, a suitable interference between both parts has to be suggested that is be able to transfer the required mechanical torque at a permissible mechanical stress. Then, the process of induction heating of the disk before its putting on the shaft is mapped. The model of the process respecting all nonlinearities is solved numerically in the hard-coupled formulation. The methodology is illustrated by the example of induction shrink fit between the active wheel of gas turbine and shaft

    Study of suitable arrangement of axial electromagnetic clutch

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    A methodology of designing axial magnetic clutch is presented. Except for the prescribed force, the clutch must satisfy certain requirements concerning its temperature rise and several other aspects. The methodology is illustrated by two examples

    Electromagnetic friction clutch for fixing accurate position of sliding elements

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    A complete mathematical model of an electromagnetic friction clutch is presented, whose numerical solution provides its basic operation characteristics. The clutch represents a part of various devices working with the movable plunger and its purpose is to fix it in a prescribed accurate position. Its application is illustrated by a typical example

    Approaches to Modernize Induction Heater for Purpose of Heat Treatment of Titanium Alloys

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    Through heating of titanium before plastic deformation is energy and time-consuming process. The main problem carrying out the process is used resistance furnaces which require a lot of time and power. The paper suggests implementing induction heating for purpose of reducing treatment time and power. In order to realize it, the authors are considering several approaches of optimization to find out optimal modes of operation. The proposed ways to optimize heater is shape and topology optimization. The ways are implemented to Comsol Multiphysics and based on obtaining results of finite element analysis. It also discusses what geometric parameters and to what extent affect the technological mode

    Model of induction shrink fit between disk and shaft

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    A complete proposal of induction shrink fit between a disk and shaft is presented. The proposal consists of two parts. First, a suitable interference between both parts has to be suggested that is be able to transfer the required mechanical torque at a permissible mechanical stress. Then, the process of induction heating of the disk before its putting on the shaft is mapped. The model of the process respecting all nonlinearities is solved numerically in the hard-coupled formulation. The methodology is illustrated with the example of induction shrink fit between the active wheel of gas turbine and shaft
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