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Number of results: 33
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Abstract

The homogeneous stirred reactor designed for kinetic studies of the combustion of hydrocarbons with intensive internal recirculation in high temperature combustion chamber is described. The originality of our reactor lies in its construction which allows to intensively mix fuel and flue gases, measure gas temperature as well as obtain samples which can be used to investigate diffusion flames. The cylindrical construction enables to use the reactor in laboratory cylindrical electrically heated ovens. The CFD analysis of the reactors, the mixing parameters (turbulent Peclet number and mixing level) and the volume average temperature in the reactors were elaborated on the basis of the typical dimensions of classical reactors to kinetics research as well as the own reactor design. The results of the analysis allow to reveal advantages of our construction.
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Abstract

The paper presents methods of on-line and off-line estimation of UAV position on the basis of measurements from its integrated navigation system. The navigation system installed on board UAV contains an INS and a GNSS receiver. The UAV position, as well as its velocity and orientation are estimated with the use of smoothing algorithms. For off-line estimation, a fixed-interval smoothing algorithm has been applied. On-line estimation has been accomplished with the use of a fixed-lag smoothing algorithm. The paper includes chosen results of simulations demonstrating improvements of accuracy of UAV position estimation with the use of smoothing algorithms in comparison with the use of a Kalman filter.
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Abstract

An economical alternative for the steel industry which uses a separate ferrosilicon and aluminum for the deoxidization of steel is a complex deoxidizer in the form of FeSiAl alloys. The effectiveness of complex deoxidizers is higher and they have a positive effect on quality improvement and also for mechanical properties of the finished steel. It is associated with a smaller number of non-metallic inclusions and a more favorable its distribution in the structure of steel. Noteworthy are the waste from the mining industry simultaneously contains SiO2 and Al2O3 oxides with a few of dopants in the form of CaO, MgO, FeO, TiO2 oxides. These wastes are present in large quantities and can be a cheap raw material for obtaining complex FeSiAl ferroalloys by an electrothermal method. “Poor” hard coal grades which so far did not apply as a reducing agent in the ferroalloy industry because of the high ash content can also be a raw material for the electrothermal FeSiAl process. The electrothermal FeSiAl melting process is similar to the ferrosilicon process in the submerged arc furnace. For this reason, a model based on Gibbs’ free enthalpy minimization algorithm was used to analyze the simultaneous reduction of SiO2 and Al2O3 oxides, which was originally elaborated for the ferrosilicon smelting process. This is a system of two closed reactors: the upper one with the lower temperature and the lower one with the higher temperature. Between the reaction system and the environment, and between the reactors inside the system, there is a cyclical mass transfer in moments when the state of equilibrium is reached in the reactors. Based on the model, the basic parameters of the electrothermal reduction process of SiO2 and Al2O3 oxides were determined and a comparative analysis was made towards the ferrosilicon process.
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Abstract

The prevalence of vitamin D deficiency in the American and European population is estimated to be extremely high. Although fewer people today suff er from serious health problems related to calcium and phosphate metabolism resulting from vitamin D deficiency, there are more and more studies suggesting that calcitriol may play an important role in the pathogenesis of other diseases in virtually every body system. A growing body of research shows that through its ubiquitously expressed receptor, calcitriol displays potent anti-angiogenic an anti-inflammatory activity. Th is review summarizes recent discoveries regarding these non-classical eff ects of vitamin D and their clinical implications. Data collection focused on the prevention and treatment of ocular diseases as well as on the underlying mechanisms.
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Abstract

In the paper, on the basis of our studies and the available literature data, a model of changes in the number of active centers corresponding to the structure of the reactive coal particle has been developed. A new distribution function that links the specific surface area of a particle with its porosity and reaction degree has been proposed. An equation for estimation of changes in this parameter during the reaction, on the basis of the initial value, has been presented. In the range of our data and the analysis of the literature data, the model, with satisfactory accuracy, describes internal structural changes of coal and coal char particles. The present results may constitute a basis for complex modelling of coal conversion processes. Based on the results it was found that the total active centres are related to the internal surface area and porosity of the particle. For a specific coal type, this value depends on the porosity, true density and size of the particle. Changes in total active centres, when these structural properties during thermal conversion of coal are considered, are described in equations.
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Abstract

Extremely intense development of civilization requires from foundry casting technologies very high quality and not expensive castings. In the foundries, there are many treatments that allow increasing of the final properties of produced castings such as refining, modification, heat treatment, etc. One of the methods of increasing the quality of the casting by removing inclusions from the liquid alloy is filtration. The use of ceramic-carbon foam filters in filtration process is still analysed phenomenon that allows improving the final properties of castings. A modern method of research, testing and synthesis of innovative chemical compositions allows improving the properties of such filters. In the paper the evaluation of application properties of developed ceramic-carbon bonded foam filters is presented. The quality of the foam filters is evaluated by Computer Tomography and foundry trials in pouring of liquid metal in test molds. Additionally computer simulations were made to visualize the flow characteristics in the foam filter. The analysed filters are the result of the research work of Foundry Research Institute and the Institute of Ceramics and Building Materials, Refractory Materials Department in Gliwice.
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Abstract

O b j e c t i v e: The main goal of our studies was to investigate the eff ect exerted by pulsed electromagnetic filed (PEMF) on adipocytokines secretion in cell culture supernatants from rat adipose derived stem cells (ADSCs) grown on varied energy-rich diet. Off spring and adult animals were randomly selected for two types of experimental diets: low (LF) or high fat (HF) diet for 7 weeks. After the diet period, serum glucose level was measured, ADSCs were isolated from adipose tissues from different locations. ADSCs from all experimental groups were exposed to PEMF, supernatants collected and adipokines level was determined. R e s u l t s: HF diet feed in pups/adult animals elevated blood glucose level and increased the level of adiponectin (Apn) and leptin of both genders and age measured in serum. ADSCs cell cultures originated from female pups on LF diet and exposed to PEMF released large amounts of Apn. PEMF effect exerted on Apn release was also observed in ADSCs isolated from male pups HF diet. ADSCs from female pups on LF diet exposed to PEMF released smaller amounts of leptin in comparison to cell cultures without PEMF treatment. PEMF exposure of ADSCs cell cultures originated from female adults on LF diet decreased release of Apn, contrary adult male on LF diet ADSCs under PEMF treatment produced more leptin. PEMF treated male HF diet-originated ADSCs cultures released significantly more leptin than controls. C o n c l u s i o n: Our results suggest that PEMF exposure is responsible for metabolic physiological balance effects obtained in ADSCs cultures originating from adult animals on HF diet.
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Abstract

Objective: The aim of this study was to verify if the exposure to the pulsed electromagnetic field (PEMF) infl uenced the release of proinfl ammatory cytokines from adipose-derived stem cells (ADSCs) of normal and overweight rats of various age and sex. Moreover, we compared body temperatures of normal-weight and overweight rats. Methods: ADSCs of Wistar rats were isolated from the subcutaneous area in females and paratesticular region in males, cultured and exposed to PEMF (7 Hz, 30 mT). Concentrations of proinflammatory cytokines were determined in rat sera and supernatant from ADSCs cultures exposed and non-exposed to PEMF. Body temperature (BT) was measured twice a week, using an infrared and rectal thermometer. Results: Irrespective of age and sex, animals maintained on low-fat (LF) diet had higher BT than those grown on high-fat (HF) diet. Exposure to PEMF reduced the release of TNF-α and enhanced the production of IL-6 in ADSCs cultures from female pups maintained on LF diet. In contrast, a decrease in IL-6 level was observed in PEMF-exposed ADSCs cultures from female pups grown on HF diet. A similar phenomenon, i.e. a post-exposure increase in IL-6 level was also observed in male pups fed with the LF diet. In the case of ADSCs cultures from adult rats maintained on an HF diet, either males or females, PEMF exposure contributed to a dramatic increase in TNF-α production. Conclusion: Our findings suggest that PEMF exposure may affect the production of proinflammatory cytokines in ADSCs cultures. The intergroup diff erences in BT may result from the presence of an underlying inflammation in obese rats.
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Abstract

Telocyte (TC) is an interstitial cell type with a small cellular body and extremely long tentacle-like extensions. TCs were discovered a decade ago and have specific morphological characteristics, immunohistochemical and secretome profi les, electrophysiological properties, microRNA expression. Moreover, they are different in gene expression from other cells. TCs play an important role in plenty of processes. Apparently, they are involved in homeostasis, remodelling, regeneration, repair, embryogenesis, angiogenesis and even tumorigenesis. “Telocytes need the world”, was emphasized by Professor Popescu and it will be actual at any time. This review summarizes particular features of TCs in different organs and systems, emphasizing their involvement in physiological and pathophysiological processes.
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Abstract

Background: Anorexia nervosa is a widely prevalent eating disorder that often leads to life-threatening complications. Since it mostly concerns females, many authors have focused on studying the reproductive system in anorexic women. Recently discovered telocytes may give a new insight into the pathophysiology of gynecological complications in these patients. Material and Methods: We adopted an animal model of anorexia nervosa induced by voluntary physical activity. Sixteen female Wistar rats were divided into two groups: control and activity-based anorexia. When the weight loss of activity-based anorexia (ABA) rats reached 25% animals were euthanized. Size and weight measurements as well as histopathological analysis of the reproductive organs were performed. Additionally, we used immunohistochemical staining for detection of telocytes. Results: Telocytes were identified in uteri of anorectic rats but no diff erences were observed when compared to the control group. Nevertheless, in the ABA group the weight of the uteri and the number of follicles in the ovaries decreased significantly. Conclusions: Our rat model of anorexia nervosa mimics the effects of this eating disorder that occur in the female reproductive system since we reported ovarian dysfunction and uterine involution in the experimental animals. It supports its potential role in the further studies of anorexia pathophysiology and treatment possibilities.
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Abstract

Introduction: Uterine leiomyoma is the most widespread benign tumor affecting women of childbearing age. There are still gaps in the understanding of its pathogenesiss. Telocytes are unique cells described in greater than 50 different locations inside the human body. The functional relationship of cells could clarify the pathogenesis of leiomyomata. In the current study, we focused on the identification of telocytes in all regions of the human uterus to explain their involvement in leiomyoma development. Materials and Methods: Tissue samples from a healthy and myomatous uterus were stained for c-kit, tryptase, CD34 and PDGFRα to identify telocytes. Routine histology was performed to analyze tissue morphology and collagen deposits. Results: Telocytes were detected in the cervix, corpus of the uterus and leiomyoma. The density of telocytes in fibroid foci was reduced compared with normal myometrium. Conclusions: Our results demonstrated the existence of telocytes in all parts of the human body affected and unaff ected by leiomyoma of the uterus. In addition, telocytes were also present in leiomyoma foci. Our results suggest that the reduced density of telocytes is important for the pathomechanisms of myometrial growth, demonstrating its value as a main component of the myomatous architecture.
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