Work Cycle of Internal Combustion Engine Due to Rightsizing

It is worth still working on the development of the internal combustion engine, because its time was not yet over. This was demonstrated by the author’s review of the literature, indicating at least the perspective of 2050 the universality of the engine as the primary propulsion or support in hybrid transport units. The presented considerations may have a broader perspective, when the thermodynamic problems of a thermal machine such as an internal combustion engine are indicated. This chapter deals with the issues of changing the swept volume known as downsizing/rightsizing. An equivalent swept volume was introduced, defined by the coefficients determining changes in the cylinder diameter and the stroke of the piston. An attempt was made to find the mutual relations to the efficiency of the work cycle and engine operating parameters. The research methodology was proposed as a mix of laboratory tests and theoretical analyses, on the basis of which it was established that while maintaining the same value of the downsizing index, despite the various permissible combinations of cylinder diameter and piston stroke changes, the cycle efficiency remains unchanged. The engine operating parameters are changing, resulting from the use of support systems for rightsizing geometric changes

The Analysis of Scheduling Algorithms in Microcellular 4G MIMO WINNER System

In this paper impact of resource scheduling algorithms on the in the microcellular 4G environment has been analyzed. Among studied metrics were average user throughput,average cell’s capacity and the quality of provided services,which has been defined as a percentage of users achieving given data rate with defined error rate. Well known memoryless scheduling algorithms such as Round Robin, MaxSNR and Fair Rate have been compared with the algorithms proposed for fading channels in [1], namely Proportional Fair and Score Based algorithms. The latter algorithms take into account both history of the scheduled users and channel conditions. A simple modification has been proposed for all examined scheduling algorithms and its impact on the users and system performance has been analyzed. The above modification rely on a preselection of scheduled users, thus significantly reducing number of computations at the cost of some performance loss.Presented results have been obtained for both uplink anddownlink OFDMA transmission in the multipath MIMOchannels in the Metropolitan Area scenario proposed within the WINNER project. Only the frequency adaptive transmission mode has been considered

The role of microtubules in electrotaxis of rat Walker carcinosarcoma WC256 cells

The endogenous electric field may provide an important signal for directional cell migration during cancer metastasis but the mechanism of cell electrotaxis is poorly understood. It was postulated that microtubules play a central role in the polarization and directional migration of several types of cells. In this paper we investigated the role of microtubules in electrotaxis of rat Walker carcinosarcoma WC256 cells. We found that colchicine-stimulated disassembly of microtubules caused the formation of blebs instead of lamellipodia at the front of about 45% of cells. Most of the remaining cells contracted and became rounded or transformed into non-polar cells. Depolymerization of microtubules in both subpopulations of cells reduced the directionality of cell migration to about 50% of the control, but bleb- forming cells migrated much more efficiently than lamellipodia-forming cells. The analysis of microtubules architecture in the presence of an endogenous electric field showed that there is no relationship between the direction of migration and the polarization of microtubules. These results suggest that microtubules are not indispensable for electrotaxis of WC256 cells, however they may improve the directionality of cell migration

Fenofibrate interferes with the diapedesis of lung adenocarcinoma cells through the interference with Cx43/EGF-dependent intercellular signaling

Extravasation of circulating cancer cells is regulated by the intercellular/intracellular signaling pathways that locally impair the endothelial barrier function. Co-cultures of human umbilical vein endothelial cells (HUVECs) with lung adenocarcinoma A549 cells enabled us to identify these pathways and to quantify the effect of fenofibrate (FF) on their activity. A549 cells induced the disruption and local activation of endothelial continuum. These events were accompanied by epidermal growth factor (EGF) up-regulation in endothelial cells. Impaired A549 diapedesis and HUVEC activation were seen upon the chemical inhibition of connexin(Cx)43 functions, EGF/ERK1/2-dependent signaling, and RhoA/Rac1 activity. A total of 25 μM FF exerted corresponding effects on Cx43-mediated gap junctional coupling, EGF production, and ERK1/2 activation in HUVEC/A549 co-cultures. It also directly augmented endothelial barrier function via the interference with focal adhesion kinase (FAK)/RhoA/Rac1-regulated endothelial cell adhesion/contractility/motility and prompted the selective transmigration of epithelioid A549 cells. N-acetyl-L-cysteine abrogated FF effects on HUVEC activation, suggesting the involvement of PPARα-independent mechanism(s) in its action. Our data identify a novel Cx43/EGF/ERK1/2/FAK/RhoA/Rac1-dependent signaling axis, which determines the efficiency of lung cancer cell diapedesis. FF interferes with its activity and reduces the susceptibility of endothelial cells to A549 stimuli. These findings provide the rationale for the implementation of FF in the therapy of malignant lung cancers

Electric field as a potential directional cue in homing of bone marrow-derived mesenchymal stem cells to cutaneous wounds

AbstractBone marrow-derived cells are thought to participate and enhance the healing process contributing to skin cells or releasing regulatory cytokines. Directional cell migration in a weak direct current electric field (DC-EF), known as electrotaxis, may be a way of cell recruitment to the wound site. Here we examined the influence of electric field on bone marrow adherent cells (BMACs) and its potential role as a factor attracting mesenchymal stem cells to cutaneous wounds. We observed that in an external EF, BMAC movement was accelerated and highly directed with distinction of two cell populations migrating toward opposite poles: mesenchymal stem cells migrated toward the cathode, whereas macrophages toward the anode. Analysis of intracellular pathways revealed that macrophage electrotaxis mostly depended on Rho family small GTPases and calcium ions, but interruption of PI3K and Arp2/3 had the most pronounced effect on electrotaxis of MSCs. However, in all cases we observed only a partial decrease in directionality of cell movement after inhibition of certain proteins. Additionally, although we noticed the accumulation of EGFR at the cathodal side of MSCs, it was not involved in electrotaxis. Moreover, the cell reaction to EF was very dynamic with first symptoms occurring within <1min. In conclusion, the physiological DC-EF may act as a factor positioning bone marrow cells within a wound bed and the opposite direction of MSC and macrophage movement did not result either from utilizing different signalling or redistribution of investigated cell surface receptors