Cyto- and genotoxicity evaluation of the biomedical polyesters obtained in the presence of new zinc catalytic systems

A preliminary evaluation of cyto- and genotoxicity of the biomedical polyesters obtained in the presence of new zinc catalytic systems was performed. A series of biomedical poly(ε-caprolactone)s (PCLs) and poly(rac-lactide)s (PLAs) synthesized in the presence of diethylzinc/propyl gallate or diethylzinc/gallic acid catalytic systems were tested using the luminescent bacterium Vibrio fischeri, the ciliated protozoan Spirostomum ambiguum as well as Salmonella typhimurium TA1535. The main goal of our work was to find the correlation between the zinc catalyst content in the synthesized products and cyto- or genotoxicity of the synthesized polyesters or their degradation products. To remove the metal catalyst residue, the obtained polyesters were subjected to the purification procedure. The Zn content in the synthesized polymers was determined by flame atomic absorption spectrometry. It was found that the purified PCLs and PLAs which contained the Zn below ca. 450?ppm were not cyto- or genotoxic. Importantly, the Zn content in the synthesized PCLs and PLAs after the second polymer precipitation was significantly reduced to 14?ppm. We believe that our results are satisfactory enough for the biomedical applications, i.e., for the synthesis of biomedical polyesters used as drug delivery systems.     

Automatic validation of vibration signals in wind farm distributed monitoring systems

A rapid growth of wind farms as a leading renewable energy sector has compelled a number of companies to develop dedicated distributed systems of monitoring and diagnosis (SM&D). Such systems are capable of early mechanical faults detection, which prevents from costly critical repairs. Fault detection of wind turbines is based on vibration and process signals analysis. Modern SM&D are usually advanced hardware and software technological products, which on the basis of collected data are capable of continuous execution of enormous number of analyses. However, the expansion of distributed systems has disclosed new challenges accompanying the transition from a singular signal analysis to automatic interpretation of large data sets. The paper deals with the assessment of data acquisition final products, namely the correctness of vibration signals recording process. The proposed validation, which is to be implemented a priori to data analysis, is required for significant calculation of any signal features as well as for legitimate storage of raw waveforms in the system database. The latter aspect is especially important in terms of gigabytes of disk space frequently wasted for corrupted data. The paper presents a step-by-step method for automatic signal validation, which can be implemented on a personal computer. Finally, the algorithm is evaluated on a real wind turbine database.     

Simplified numerical study of evaporation processes inside vertical tubes

The paper presents a simplified numerical model of evaporation processes inside vertical tubes. In this model only the temperature fields in the fluid domain （the liquid or two-phase mixture） and solid do- main （a tube wall） are determined. Therefore its performance and efficiency is high. The analytical formulas, which allow calculating the pressure drop and the distribution of heat transfer coefficient along the tube length, are used in this model. The energy equation for the fluid domain is solved with the Control Volume Method and for the solid domain with the Finite Element Method in order to de- termine the temperature field for the fluid and solid domains.     

Ethylene/1-olefin copolymerization behaviour of vanadium and titanium complexes bearing salen-type ligand

Ethylene/1-olefin copolymerization using vanadium and titanium complexes bearing tetradentate [O,N,N,O]-type ligand and EtAlCl₂ or MAO as a cocatalyst is carried out. In the presence of the vanadium complex activated with EtAlCl₂ is observed (a) negative “comonomer effect”, (b) high comonomer incorporation and narrow chemical composition distribution (CCD), (c) unexpected copolymer microstructure, and (d) increased molecular weight of copolymers when compared with the homopolymer. In contrast, titanium catalyst gives copolymers with lower 1-olefin content and broad CCD. Supported complexes show higher activity, lower 1-olefins incorporation and give copolymers with ultra high molecular weights.     

Environmentally friendly pathways for the evaluation of investment projects using life cycle assessment (LCA) and life cycle cost analysis (LCCA)

Issues related to improvement in the quality of products and to environmental protection in the economic policy of many countries and in the strategies of institutions and international organisations (e.g. European Union) have increased in importance in recent years as a consequence of the increase in environmental awareness of consumers. All these institutions currently recommend a comprehensive assessment of the effectiveness of planned projects during the decision-making process taking into account both economic and environmental factors. It is, therefore, important to develop methods and tools to assess environmental performance as a support to a proper choice of investment activities. The aim of this paper is to develop algorithms to link the life cycle assessment (LCA) model associated with environmental issues and the life cycle cost analysis (LCCA) model associated with economic factors to permit an integrated assessment of investment projects. The combination of LCA and LCCA results enables the assessment of ongoing or planned investments and should be used as a priority in making strategic decisions. In this paper, three environmentally friendly pathways (algorithms) using LCA–LCCA indicators as a support for decision-making processes were proposed: the first for implementing any environmental investments, the second for modernisation and innovation investments, and the third for new investments.     

A New One/Two-Dimensional Model of the Conjugate Heat Transfer in Waterwall Tubes of the Supercritical Steam Boiler Combustion Chamber

An important issue arising in supercritical steam boilers is to avoid the tube wall overheating due to high heat fluxes transferred from flue gases to the fluid. The paper presents a new hybrid one/two-dimensional model of the fluid heating in waterwall tubes in the combustion chambers of steam boilers for supercritical steam parameters. The model is based on distributed parameters. The analysis concerns tubes with externally finned surfaces. Using the proposed model, it is possible to estimate zones and locations where the tube wall overheating may occur. One-dimensional equations describing the mass, momentum and energy conservation are formulated and solved for the fluid domain. Each analyzed cross section of the finned waterwall tube is divided into 20 control volumes for which energy balance equations are solved in a two-dimensional space. In order to analyses the conjugate heat transfer between the waterwall tube and the fluid, the heat transfer coefficient is computed using the Kitoh correlation. The computations assume a variable heat flux along the combustion chamber height. Also, the heat flux variation on the waterwall tube circumference is incorporated within the model. The reduction in dimensionality in both the fluid and the solid domains leads to an improvement in the computational performance compared to complex three-dimensional computational fluid dynamics simulations. The paper presents an application of the proposed hybrid model to simulate heat and flow processes occurring in waterwall tubes of a supercritical boiler operating in one of the Polish power plants. The results of the simulations are compared with the data obtained from measurements and good agreement is obtained. Therefore, the developed model can be successfully applied, e.g. in simulators of the supercritical power boiler operation.     

At the Edges of Photosynthetic Metabolic Plasticity—On the Rapidity and Extent of Changes Accompanying Salinity Stress-Induced CAM Photosynthesis Withdrawal

The common ice plant (Mesembryanthemum crystallinum L.) is a facultative crassulacean acid metabolism (CAM) plant, and its ability to recover from stress-induced CAM has been confirmed. We analysed the photosynthetic metabolism of this plant during the 72-h response period following salinity stress removal from three perspectives. In plants under salinity stress (CAM) we found a decline of the quantum efficiencies of PSII (Y(II)) and PSI (Y(I)) by 17% and 15%, respectively, and an increase in nonphotochemical quenching (NPQ) by almost 25% in comparison to untreated control. However, 48 h after salinity stress removal, the PSII and PSI efficiencies, specifically Y(II) and Y(I), elevated nonphotochemical quenching (NPQ) and donor side limitation of PSI (Y_ND), were restored to the level observed in control (C₃ plants). Swelling of the thylakoid membranes, as well as changes in starch grain quantity and size, have been found to be components of the salinity stress response in CAM plants. Salinity stress induced an over 3-fold increase in average starch area and over 50% decline of average seed number in comparison to untreated control. However, in plants withdrawn from salinity stress, during the first 24 h of recovery, we observed chloroplast ultrastructures closely resembling those found in intact (control) ice plants. Rapid changes in photosystem functionality and chloroplast ultrastructure were accompanied by the induction of the expression (within 24 h) of structural genes related to the PSI and PSII reaction centres, including PSAA, PSAB, PSBA (D₁), PSBD (D₂) and cp43. Our findings describe one of the most flexible photosynthetic metabolic pathways among facultative CAM plants and reveal the extent of the plasticity of the photosynthetic metabolism and related structures in the common ice plant.     

The VIT technology for rapid detection of Listeria monocytogenes and other Listeria spp

Detection of Listeria monocytogenes is generally performed in a two-step cultural enrichment process and takes on average 1 week until the biochemical identification of a L. monocytogenes suspicious colony is completed. However, food processing companies depend increasingly on test methods, which attempt to generate results comparable to standard methods but in reduced time-frame and which allow to release produced batches dependent on such results. In the present study, the vermicon identification technology (VIT), a rapid commercial test system using fluorescently labelled gene probes, was compared to a cultural standard method. In total, 298 naturally contaminated samples were analysed. The sensitivity and the specificity of the VIT system were 100% for the detection of L. monocytogenes and 97.1% and 100%, respectively, for the detection of the genus Listeria.     

Serum microRNAs in Systemic Sclerosis,Associations with Digital Vasculopathy and Lung Involvement

Background and aims: Systemic sclerosis (SSc) is an autoimmune, rare multisystem chronic disease that is still not well-understood aetiologically and is challenging diagnostically. In the literature, there are ever-increasing assumptions regarding the epigenetic mechanisms involved in SSc development; one of them is circulating microRNAs. Many of them regulate TLR pathways and are significant in autoimmune balance. The aim of this study was to determine profile expression of selected microRNAs in SSc patients, including miR-126, -132, -143, -145, -155, -181a, -29a and -3148, in comparison to healthy controls. Methods: Serum microRNAs were isolated from 45 patients with SSc and 57 healthy donors (HC). Additionally, SSc patients were considered in the aspect of disease subtype, including diffuse systemic sclerosis (dcSSc) and limited systemic sclerosis (lcSSc). Results: miR-3148 was detected neither in the serum of HC nor in SSc patients. All of the rest of the analyzed microRNAs, excluding miR-126, miR-29a and miR-181a, were significantly upregulated in SSc patients in comparison to HC. However, miR-181a has been revealed only in the serum of patients with lcSSc but not dcSSc. Moderate positive correlations between the transfer factor of the lung for carbon monoxide (TLCO) and miR-126 and miR-145 were observed. A significant correlation has been found between serum miR-143 level and forced vital capacity (FVC). SSc patients with FVC ≤ 70% were characterized by significantly lower levels of miR-143 compared to patients with normal FVC. Additionally, the expression of miR-132 was significantly higher in dcSSc subgroup with detected active lung lesions compared to dcSSc patients with fibrotic lesions. Patients with an early scleroderma pattern of microangiopathy seen on nailfold video-capillaroscopy (NVC) revealed higher expression of miR-155 in serum than those with a late pattern. Conclusions: The expression profile of circulating cell-free miRNAs is significantly changed in the serum of SSc patients compared to healthy individuals. Downregulation of miRNA-181a and overexpression of miR-132, miR-143, miR-145 and miR-155 in serum may be significant in SSc in the context of biomarkers.     

Role of RBMS3 Novel Potential Regulator of the EMT Phenomenon in Physiological and Pathological Processes

RNA-binding protein 3 (RBMS3) plays a significant role in embryonic development and the pathogenesis of many diseases, especially cancer initiation and progression. The multiple roles of RBMS3 are conditioned by its numerous alternative expression products. It has been proven that the main form of RBMS3 influences the regulation of microRNA expression or stabilization. The absence of RBMS3 activates the Wnt/β-catenin pathway. The expression of c-Myc, another target of the Wnt/β-catenin pathway, is correlated with the RBMS3 expression. Numerous studies have focused solely on the interaction of RBMS3 with the epithelial–mesenchymal transition (EMT) protein machinery. EMT plays a vital role in cancer progression, in which RBMS3 is a new potential regulator. It is also significant that RBMS3 may act as a prognostic factor of overall survival (OS) in different types of cancer. This review presents the current state of knowledge about the role of RBMS3 in physiological and pathological processes, with particular emphasis on carcinogenesis. The molecular mechanisms underlying the role of RBMS3 are not fully understood; hence, a broader explanation and understanding is still needed.