Efficiency optimisation of the thermal energy storage unit in the form of the ceiling panel for summer conditions

The thermal energy storage unit in the form of the ceiling panel made of the gypsum‐microencapsulated phase change material composite with internal U‐shaped channels was optimised applying previously developed 1D‐3D numerical simulator. Calculations were carried out for variable inlet velocities of air, different properties of the composite expressed by enthalpy‐temperature curves, and summer climatic conditions in Central Poland (Warsaw). Optimal working temperature ranges of the composite were determined. Moreover, studies showed that for Central Poland, composites with wide ranges of the working temperature are preferred due to significant daily variations of ambient temperature during the whole summer.     

The Profile of MicroRNA Expression and Potential Role in the Regulation of Drug-Resistant Genes in Doxorubicin and Topotecan Resistant Ovarian Cancer Cell Lines

Epithelial ovarian cancer has the highest mortality among all gynecological malignancies. The main reasons for high mortality are late diagnosis and development of resistance to chemotherapy. Resistance to chemotherapeutic drugs can result from altered expression of drug-resistance genes regulated by miRNA. The main goal of our study was to detect differences in miRNA expression levels in two doxorubicin (DOX)- and two topotecan (TOP)-resistant variants of the A2780 drug-sensitive ovarian cancer cell line by miRNA microarray. The next aim was to recognize miRNAs as factors responsible for the regulation of drug-resistance genes. We observed altered expression of 28 miRNA that may be related to drug resistance. The upregulation of miR-125b-5p and miR-935 and downregulation of miR-218-5p was observed in both DOX-resistant cell lines. In both TOP-resistant cell lines, we noted the overexpression of miR-99a-5p, miR-100-5p, miR-125b-5p, and miR-125b-2-3p and decreased expression of miR-551b-3p, miR-551b-5p, and miR-383-5p. Analysis of the targets suggested that expression of important drug-resistant genes such as the collagen type I alpha 2 chain (COL1A2), protein Tyrosine Phosphatase Receptor Type K (PTPRK), receptor tyrosine kinase—EPHA7, Roundabout Guidance Receptor 2 (ROBO2), myristoylated alanine-rich C-kinase substrate (MARCK), and the ATP-binding cassette subfamily G member 2 (ABCG2) can be regulated by miRNA.     

miRNAs Participate in the Regulation of Oxidative Stress-Related Gene Expression in Endometrioid Endometrial Cancer

Reactive oxygen species are formed as by-products of normal cell metabolism. They are needed to maintain cell homeostasis and signaling, which is possible due to defense systems. Disruption of this balance leads to oxidative stress that can induce cancer. Redox regulation by miRNAs may be a potential therapeutic target. The aim of the study was to assess the activity of genes associated with oxidative stress in endometrial cancer and to determine their relationship with miRNAs. The study included 45 patients with endometrioid endometrial cancer and 45 without neoplastic changes. The expression profile of genes associated with oxidative stress was determined with mRNA microarrays, RT-qPCR and ELISA. The miRNA prediction was performed based on the miRNA microarray experiment and the mirDB tool. PRDX2 and AQP1 showed overexpression that was probably not related to miRNA activity. A high level of PKD2 may be the result of a decrease in the activity of miR-195-3p, miR-20a, miR-134. A SOD3 level reduction can be caused by miR-328, miR-363. In addition, miR-363 can also regulate KLF2 expression. In the course of endometrial cancer, the phenomenon of oxidative stress is observed, the regulation of which may be influenced by miRNAs.     

CTLA-4 Expression Is a Promising Biomarker of Idiopathic Pulmonary Arterial Hypertension and Allows Differentiation of the Type of Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) is an increasingly frequently diagnosed disease, the molecular mechanisms of which have not been thoroughly investigated. The aim of our study was to investigate subpopulations of lymphocytes to better understand their role in the molecular pathomechanisms of various types of PAH and to find a suitable biomarker that could be useful in the differential diagnosis of PAH. Using flow cytometry, we measured the frequencies of lymphocyte subpopulations CD4+CTLA-4+, CD8+ CTLA-4+ and CD19+ CTLA-4+ in patients with different types of PAH, namely pulmonary arterial hypertension associated with congenital heart disease (CHD-PAH), pulmonary arterial hypertension associated with connective tissue disorders (CTD-PAH), chronic thromboembolic pulmonary hypertension (CTEPH) and idiopathic pulmonary arterial hypertension (iPAH), and in an age- and sex-matched control group in relation to selected clinical parameters. Patients in the iPAH group had the significantly highest percentage of CD4+CTLA-4+ T lymphocytes among all PAH groups, as compared to those in the control group (p < 0.001), patients with CTEPH (p < 0.001), CTD-PAH (p < 0.001) and CHD-PAH (p < 0.01). In iPAH patients, the percentages of CD4+CTLA-4+ T cells correlated strongly positively with the severity of heart failure New York Heart Association (NYHA) Functional Classification (r = 0.7077, p < 0.001). Moreover, the percentage of B CD19+CTLA-4+ cells strongly positively correlated with the concentration of NT-proBNP (r = 0.8498, p < 0.001). We have shown that statistically significantly higher percentages of CD4+CTLA-4+ (p ≤ 0.01) and CD8+ CTLA-4+ (p ≤ 0.001) T cells, measured at the time of iPAH diagnosis, were found in patients who died within 5 years of the diagnosis, which allows us to consider both of the above lymphocyte subpopulations as a negative prognostic/predictive factor in iPAH. CTLA-4 may be a promising biomarker of noninvasive detection of iPAH, but its role in planning the treatment strategy of PAH remains unclear. Further studies on T and B lymphocyte subsets are needed in different types of PAH to ascertain the relationships that exist between them and the disease.     

Monte Carlo simulation of radiation-induced solid state polymerization

A Monte Carlo method was used for a computer simulation of radiation-induced solid state polymerization. The propagation of polymer chains was simulated by means of self-avoiding random walks on a tetrahedral lattice. The initiation and termination of the chains were modelled by pseudorandom processes. The influence of conditions of the in-source process on the post-polymerization kinetics and on the degree of polymerization of the polymers was studied.     

Microstructure and mechanical properties of fine grained carbon-bonded Al2O3–C materials

Fine grained carbon-bonded Al₂O₃–C materials as used in ceramic filters have been manufactured by uniaxial and isostatic pressing, respectively. The variation in the microstructure over the cross section of the samples which in particular depends on the shaping technique plays an important role in the wetting of the material by liquid steel. Moreover, the amount and grain size of the binder has a decisive influence on the porosity and bulk density and therefore on the mechanical properties. For this, two different grain size distributions of Carbores^® P binder were used, and in addition the fraction of binder was varied from 5–30 wt%. Tests of the cold crushing strength and of the cold modulus of rupture were performed at room temperature. The adjusted bulk density, open porosity and shrinkage of the samples were determined and the microstructure was analyzed by means of scanning electron microscopy. For control of a homogeneous distribution of carbon in the samples, the residual carbon content was measured also within individual samples at different positions.     

Some Remarks on the Classification of Water Vapor Sorption Isotherms and Blahovec and Yanniotis Isotherm Equation

Mathematical analysis was performed on equations describing water vapor sorption isotherms. It was shown that an identity exists between the Blahovec and Yanniotis (BY), D'Arcy and Watt (DW), and generalized D'Arcy and Watt (GDW) models. The original BY model has been modified to account for temperature dependence of the model parameters. This modification enables the application of this model to describe sorption data obtained at different temperatures. A new method for classification of sorption isotherms has been proposed that is much simpler than the classification established by Blahovec and Yanniotis.     

Sorption Properties of Vacuum-Dried Strawberries

This work demonstrates the influence of changes in parameters of vacuum drying (temperature and pressure) on the sorption properties of dried strawberries. Fruits were dried at 50 and 70°C under pressures of 4 and 16 kPa. Vacuum drying was also conducted during the first 4 h at 70°C and then the temperature was decreased to 50°C at a pressure of 4 kPa. The other combination included increasing the pressure after the first 4 h from 4 to 16 kPa at a drying temperature of 70°C. Sorption isotherms were determined in the dried strawberries. It was shown that with increasing drying temperatures, there was a notable deterioration in the capacity for absorbing water vapor by the vacuum-dried fruit. On the other hand, the pressure at which vacuum drying proceeded did not significantly affect water vapor absorption. Changing the parameters of vacuum drying—that is, temperature in the range of 50–70°C and pressure in the range of 4–16 kPa—affected the shape and structure of the resultant dried strawberries. The combination of vacuum drying with convective drying also influenced the shape and structure of the dried fruit.     

CHANGES OF RHEOLOGICAL PROPERTIES OF APPLE TISSUE UNDERGOING CONVECTIVE DRYING

ABSTRACT

The aim of this work was to investigate rheological properties of apple cubes undergoing convective drying. Compression-relaxation test was used to follow changes of properties under investigation.

Raw apple appeared to be very heterogeneous material from the rheological point of view. The relationship between stress and strain was concave downwards and the concavity increased until water content of 2·5 g/g d.m. was reached. Then the relationship begun to straighten and for dry material developed stress was linearly dependent on strain. The resistance of deformation decreased with decreasing water content. Analysis of relaxation showed that the rate of relaxation increased with decreasing water content and the unrelaxed stress was smaller the lower was the water content.

Apple cubes undergoing drying are pictured as material composed of three compartments with different rheological properties. The outer layer is dry, inelastic and difficult to deform. Underneath is moist material with no turgor and relatively easy to compress, and the core with properties of raw apples. During drying the second layer grows in expense of the core and porous structure with many voids filled with air is formed. Share of each compartment in the volume of apple cube undergoing drying affects average rheological properties of the material.     

The Role of MgCl2 as Supporter for the New Generation of Olefin Polymerization Catalysts

Most of the research in the field of olefin polymerization is focused on TiC1, catalysts on a specially prepared MgCl, support. In order to combine a high polymer yield with good stereoselectivity, a complexed cocatalyst is used. Most frequently it is a mixture of AIEtzCl or AlEt, with an electron donor such as tetrahydrofuran (THF) or ethyl benzoate for ethylene and propylene polymerization, respectively.