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The paper presents the results of the research on the impact of process parameters of high-pressure, cold-chamber die casting of an industrial casting made of aluminium alloy on the casting properties assessed macroscopically by measuring the casting average density and microscopically through the characteristics of the casting microstructure. The analysis covers the influence of three selected velocity settings of the pressing plunger, which determine the filling time, and three values of the compression pressure setting characteristic of the third phase of the casting process. The cooling and solidification simulations of the casting were performed using the ProCAST software. During the simulation tests, the impact of the filling rate of the alloy into the die cavity on the cooling rate and the alloy solidification path at selected points were determined. The conducted research allowed linking the process parameters with the parameters of the casting structure with different wall thicknesses. Metallographic examinations of the castings were carried out using a light microscopy, SEM, and EDS analysis. The fraction of the phases α(Al), the size of dendritic cells, and the size of silicon particles, in the cross-sections of the castings with wall thickness of 3, 6, and 11 mm, respectively, were determined.

Magnesium and its alloys have been in the focus of investigation as a material for biomedical applications. The reason is that magnesium shows biodegradable properties, it could promote bone-healing effect. As it has been reported in resent studies magnesium is non-toxic, and non-allergic those criteria makes magnesium and its alloys (Mg20Zn, Mg19Zn1Ca) very attractive for orthopedic applications. It is known, that magnesium reacts easily with chlorides ions, those are present mainly in body’s liquids. In this study, organic coatings were applied for corrosion protection of magnesium alloys in aggressive conditions. Organic coatings were deposited by spin coater. The chitosan composite coatings were obtained by the addition of silicon glass and hydroxyapatite to 1% chitosan solution in the lactic acid. Electrochemical methods (Linear sweep voltamperometry (LSV), Open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) were used as well as investigate corrosion behaviour of tested samples. Hydrogen evolution tests has been performed to determine corrosion rate. The chemical composition and structure of corrosion products deposited after corrosion tests were investigated by using Fe-SEM/EDS and Xray photoelectron spectroscopy (XPS) analysis. The application of organic coatings on the Mg20Zn and Mg19Zn1Ca alloys promote corrosion resistance in solutions with high concentration of Cl-. Acknowledgements The authors would like to thanks to European Commission for financial support in the frame of project H2020-MSCA-ITN-2017, grant agreement no. 764977 –mCBEEs.

Każde przedsiębiorstwo wymaga nieustannych przemyślanych zmian, które w razie konieczności dostosują je do zmieniającej się rzeczywistości. W dobie silnej konkurencji i niepewności sytuacji rynkowej priorytetową rolę w logistyce odgrywają prognozy. Są one odpowiedzialne za szereg działań, takich jak wyprodukowanie, dostarczenie, a w dalszej kolejności sprzedanie właściwej ilości produktów lub usług, na jakie w danym czasie występuje przewidywany popyt (zainteresowanie). Prognozowanie jest narzędziem bardzo korzystnym, bowiem ułatwia osiągnięcie równowagi rynkowej. Dlatego też celem niniejszego artykułu jest ukazanie możliwości, jakie daje wykorzystanie metod prognostycznych w tej interdyscyplinarnej dziedzinie nauki.

Mg alloys exhibit attractive mechanical properties, low density and high strength-to-weight ratio. Therefore they are widely used as structural materials in the automotive and aerospace sectors. In recent years, Mg alloys are considered as a new class of biodegradable implant materials. It has been revealed that magnesium alloys exhibit very good biocompatibility and their density is close to that of natural bones (1.8 - 2.1 g cm 3 ). In vitro and in vivo studies have shown that magnesium alloys easily undergo resorption and do not cause allergic reactions. Magnesium alloys exhibit very low corrosion resistance in physiological solutions. The corrosion mechanism of Mg1Ca1Si magnesium alloys in the Ringer solution was investigated by means of electrochemical techniques like: Linear Sweep Voltamperommetry (LSV), Electrochemical Impedance Spectroscopy (EIS), chronoamperometry were performed. All electrochemical measurements have been performed in the Ringer solution at 37C and pH = 7.2. The surface analysis after corrosion tests were performed by using FE-SEM. Moreover, the chemical analysis of the solution after corrosion tests was performed by ICP-MS and UV-vis spectroscopy. It has been revealed that the corrosion of Mg1Ca1Si alloys starts at the interface matrix / precipitates and the eutectic (mixture of  and Mg 2 Ca phases) is a week place where the corrosion starts. After corrosion tests the magnesium and calcium species were detected in the solution. In order to improve the corrosion resistance the chitosan coatings were deposited on the surface of Mg1Ca1Si alloy. The electrochemical tests have been shown that such coatings enhance the corrosion resistance of Mg alloy in the Ringer solution. Acknowledgements The authors would like to thanks to European Commission for financial support in the frame of project H2020- MSCA-ITN-2017, grant agreement no. 764977 -mCBEEs

In recent years magnesium and its alloys became one of most promising materials to be used in biomedical applications. Because of its strength, toughness, elasticity modulus is very similar to the human bones. Moreover, it takes part in different important living processes in nature at all, and in humans body in particular. Magnesium shows very good biocompatible and biodegradable properties but it the other hand its nonstable in the solutions containing the chloride ions. To improve corrosion resistance of magnesium it was applied natural biopolymeric chitosan coating. In this work, the corrosion rate of Mg19Zn1Ca alloy in the Hank’s solution was investigated. In order to study the corrosion degradation of Mg alloys the following electrochemical techniques were used: Linear Sweep Voltamperommetry (LSV), Electrochemical Impedance Spectroscopy (EIS), chronoamperometry. The corrosion tests were performed in the Hank’s solution at 37°C and pH = 7.2. The microstructure of alloys has been investigated by means of XRD and FE-SEM/EDS measurements. Surface analysis techniques like XPS and FT-IR were used to study the chemical composition corrosion products. Magnesium alloys undergo the active corrosion in the Hank’s solution. The chitosan based coatings deposited on the surface of Mg alloys significantly reduce their corrosion rate. Chitosan layer on the surface of Mg alloys produce corrosion protective film and also to shows antibacterial properties. Acknowledgements The authors would like to thanks to European Commission for financial support in the frame of project H2020-MSCA-ITN-2017, grant agreement no. 764977 –mCBEEs.

AGH – University of Science and Technology, Faculty of Foundry Engineering, Reymonta 23 street, 30-059 Krakow, Poland Corresponding author (H. Krawiec): krawiec@agh.edu.pl Magnesium and its alloys exhibit low density and high strength-to-weight ratio. In recent years, many studies are devoted to the application of Mg alloys as a new class of biodegradable implant materials. It has been revealed that pure magnesium exhibits very good biocompatibility and its density is close to that of natural bones (1.8 - 2.1 g cm3). However, the low corrosion resistance of magnesium alloys in physiological fluids significantly limits their application in the biomedical sector. In vitro and in vivo studies have shown that magnesium alloys easily undergo resorption and do not cause allergic reactions. Fast corrosion of magnesium alloys is related with the presence of high concentration of chloride ions in the body fluids. In order to improve the corrosion resistance of Mg alloys and to hinder their dissolution in physiological fluids, it is necessary to perform surface treatment (coatings, laser treatment...). In this work, the corrosion behaviour of several magnesium alloys (Mg20Zn and Mg19Zn1Ca) have been investigated in the Hank’s solution at 37 °C. In order to improve the corrosion resistance of Mg alloys, protective chitosan coatings were deposited by means of spin coater. The following types of coatings were deposited on the surface of Mg alloys: chitosan, chitosan containing TiO2 nanoparticles and chitosan with addition of NaF and glass silica. Chitosan is a biodegradable polymer which is safe for health. The electrochemical performance of coated magnesium alloys was evaluated by linear sweep voltamperometry (LSV) and electrochemical impedance spectroscopy. The structure of coatings has been investigated by using Fourier – Transform Infrared (FTIR) spectroscopy. The corrosion tests have revealed that the chitosan coating improves the corrosion resistance of magnesium alloys in simulated body fluids. The highest corrosion resistance of Mg alloys was found when the chitosan coatings containing NaF and Na2SiO3 salts were deposited on their surface. Acknowledgements The authors would like to thanks to European Commission for financial support in the frame of project H2020-MSCA-ITN-2017, grant agreement no. 764977 –mCBEEs. &nbsp

A methodological approach to perceptual learning was used to allow both early blind subjects (experimental group) and blindfolded sighted subjects (control group) to experience optical information and spatial phenomena, on the basis of visuo-tactile information transmitted by a 64-taxel pneumatic sensory substitution device. The learning process allowed the subjects to develop abilities in spatial localisation, shape recognition (with generalisation to different points of view), and monocular depth cue interpretation. During the training phase, early blind people initially experienced more difficulties than blindfolded sighted subjects (having previous perceptual experience of perspective) with interpreting and using monocular depth cues. The amelioration of the performance for all blind subjects during training sessions and the quite similar level of performance reached by two groups in the final navigation tasks suggested that early blind people were able to develop and apply cognitive understanding of depth cues. Both groups showed generalisation of the learning from the initial phases to cue identification in the maze, and subjectively experienced shapes facing them. Subjects' performance depended not only on their perceptual experience but also on their previous spatial competencies.

This method is based on the determination of similarity criterion Z as the average temperature difference between the reference and analyzed curves in the solidification region. The purpose of this work is to describe the thermal express-analysis (TDA) device created by us and the substantiation of the reliability and sensitivity of the results of the new method, including the definition of a two-sided confidence interval using Student's t-test. The error of the method was determined with the Student's criterion taken into account. The high sensitivity of the method to the metallurgical prehistory of the gray and white cast iron melts was confirmed. The method has been successfully tested under laboratory and experimental-industrial conditions on induction melting cast iron. The new method uses a disposable environmentally friendly submersible steel sampler with a heat-resistant coating inside and out. The method allows for the quick adaptation to the conditions of specific foundries (especially with the frequent changes of classes and types of cast iron) due to replenishing the database of the reference samples. The basic features of the new method are its universality, self-adaptability, speed, relative simplicity, and high sensitivity to the metallurgical prehistory of molten iron.

A gene encoding a major secreted antigen, SagA, was identified in Enterococcus faecium by screening an E. faecium genomic expression library with sera from patients with E. faecium -associated endocarditis. Recombinant SagA protein showed broad-spectrum binding to extracellular matrix (ECM) proteins, including fibrinogen, collagen type I, collagen type IV, fibronectin, and laminin. A fibrinogen-binding protein, purified from culture supernatants of an E. faecium clinical isolate, was found to match the N-terminal sequence of the predicted SagA protein and to react with the anti-SagA antibody, confirming that it was the SagA protein; this protein appeared as an 80- to 90-kDa smear on a Western blot that was sensitive to proteinase K and resistant to periodate treatment and glycoprotein staining. When overexpressed in E. faecium and Escherichia coli , the native and recombinant SagA proteins formed stable oligomers, apparently via their C-terminal domains. The SagA protein is composed of three domains: (i) a putative coiled-coil N-terminal domain that shows homology to the N-terminal domain of Streptococcus mutans SagA protein (42% similarity), previously shown to be involved in cell wall integrity and cell shape maintenance, and to the P45 protein of Listeria monocytogenes (41% similarity); (ii) a central domain containing direct repeats; and (iii) a C-terminal domain that is similar to that found in various proteins, including P45 (50% similarity) and P60 (52% similarity) of L. monocytogenes . The P45 and P60 proteins both have cell wall hydrolase activity, and the latter has also been shown to be involved in virulence, whereas cell wall hydrolase activity was not detected for SagA protein. The E. faecium sagA gene, like the S. mutans homologue, is located in a cluster of genes encoding proteins that appear to be involved in cell wall metabolism and could not be disrupted unless it was first transcomplemented, suggesting that the sagA gene is essential for E. faecium growth and may be involved in cell wall metabolism. In conclusion, the extracelluar E. faecium SagA protein is apparently essential for growth, shows broad-spectrum binding to ECM proteins, forms oligomers, and is antigenic during infection.

The first outbreak caused by vancomycin-resistant enterococci of the VanB phenotype in Poland was analyzed. It occurred in a single ward of a Warsaw hospital which is a specialized center for the treatment of hematological disorders. Between July 1999 and February 2000, 11 patients in the ward were found to be infected and/or colonized by Enterococcus faecium that was resistant in vitro to vancomycin and susceptible to teicoplanin. PCR analysis confirmed that the vancomycin-resistant E. faecium (VREM) isolates carried the vanB gene, which is responsible for the VanB phenotype. Pulsed-field gel electrophoresis (PFGE) typing revealed that the isolates belonged to four distinct PFGE types and that one of these was clearly predominant, including isolates collected from seven different patients. The isolates contained one or more copies of the vanB gene cluster of the identical, unique Dra I/ Pag I ( Bsp HI) restriction fragment length polymorphism type, which resided in either the same or different plasmid molecules or chromosomal regions. All this data suggested that the outbreak was due to both clonal spread of a single strain and horizontal transfer of resistance genes among nonrelated strains, which could be mediated by plasmids and/or by vanB gene cluster-containing transposons. The comparative analysis of vancomycin-susceptible E. faecium (VSEM) isolates collected from infections in the same ward at the time of the VREM outbreak has led to identification of a widespread VSEM strain that was possibly related to the major VREM clone. It is very likely that this endemic VSEM strain has acquired vancomycin-resistance determinants and that the acquisition occurred more than once during the outbreak.

Twenty-two vancomycin-resistant enterococcal (VRE) isolates of the VanA phenotype (21 Enterococcus faecium isolates and 1 E. faecalis isolate), representative of a large outbreak that occurred in a hospital in Gdańsk, Poland, were studied. All of the isolates demonstrated resistance to a wide variety of other antimicrobial agents in addition to glycopeptides. Several lines of evidence suggested that the outbreak most probably consisted of two epidemics that followed the independent introduction of VanA determinants into two separate hematological wards of the hospital. This hypothesis is supported by the fact that isolates recovered in these wards possessed two different polymorphs of the highly conserved DNA region encompassing the vanRSHAX genes and two distinct polymorph types of Tn1546-like transposons, which contain these genes. According to pulsed-field gel electrophoresis data, the outbreak in the adult hematology ward (HW) was highly polyclonal, which suggested a major role for the horizontal transmission of Tn1546-like elements among nonrelated strains of E. faecium and E. faecalis in this environment. On the other hand, the outbreak in the pediatric hematology ward (PHW) was most probably due to the clonal spread of two epidemic E. faecium strains, which had exchanged a plasmid carrying the Tn1546-like transposon. Restriction fragment length polymorphism studies of transposons and their insertionloci in plasmid DNA have suggested that numerous isolates from both HW and PHW contained two or more copies of Tn1546-like elements that underwent diversification due to various genetic modifications. The reported data demonstrated a very complex epidemiology of the first, and up to now the only, VanA VRE outbreak characterized in Poland.

A novel type II restriction endonuclease UnbI was isolated from an unidentified psychrofilic bacterial strain from Antarctica. UnbI recognizes and cleaves the sequence 5'-GGNCC-3', producing 5 nucleotide long sticky ends. In this respect it differs from its neoschizomer Sau96I and all other restriction enzymes recognizing this sequence. UnbI has a relatively low temperature optimum of 15 degrees C to 20 degrees C and its activity is completely inhibited by inorganic phosphate.

A mixed outbreak caused by vancomycin-resistant Enterococcus raffinosus and Enterococcus faecium carrying the vanA gene was analysed. The outbreak occurred in a large hospital in Poland and affected 27 patients, most of whom were colonised, in three wards, including the haematology unit. The E. raffinosus isolates had a high-level multiresistant phenotype and were initially misidentified as Enterococcus avium; their unambiguous identification was provided by multilocus sequence analysis. The molecular investigation demonstrated the clonal character of the E. raffinosus outbreak and the polyclonal structure of the E. faecium isolates. All of the isolates carried the same Tn1546-like element containing an IS1251-like insertion sequence, located on a c. 50-kb conjugative plasmid. One of the E. faecium clones, found previously to be endemic in the hospital, was probably the source of the plasmid. The results of the study suggest that difficulties in identification may have led to an underestimate of the importance of E. raffinosus in vancomycin-resistant enterococci (VRE) control strategies.

To study the population structure of Enterococcus faecalis from Polish hospitals, 291 isolates were typed by pulsed-field gel electrophoresis and a novel multilocus sequence typing scheme (P. Ruiz-Garbajosa et al., J. Clin. Microbiol. 44:2220-2228, 2006). The isolates originated from geographically widespread medical institutions and were recovered during a 10-year period (1996 to 2005) from different clinical sources. The analysis grouped the isolates into five epidemic and 71 sporadic clones. The importance of the previously identified global clonal complexes CC2 and CC9 was corroborated by our findings that two of the Polish epidemic clones, A and J, were classified into these clonal complexes (CCs). However, the two most predominant clones, C (ST40) and F (CC87), did not cluster in the aforementioned CCs and may represent novel epidemic CCs. These clones may have emerged in Central Europe. Clone F, carrying glycopeptide resistance determinants of VanA or VanB phenotypes, caused several outbreaks in hematology units and appeared to be the most prevalent clone in recent years in Poland. Antimicrobial susceptibility testing and additional tests for pathogenicity-related phenotypes (hemolysin and gelatinase production) and genes ( asa1 and esp ) were performed to further characterize these epidemic clones. Multidrug resistance, glycopeptide resistance, presence of asa1 , and production of hemolysin appeared to be statistically significant features related to epidemicity. Production of gelatinase was significant for two of the epidemic clones, whereas presence of the esp gene was not specific for the epidemic clones.

A previously identified gene sprE of Enterococcus faecalis strain OG1 was shown to encode an extracellular serine protease that appears to belong to the glutamyl endopeptidase I staphylococcal group. A single form of SprE with a molecular mass of 25 kDa and a pH optimum between 7.0 and 7.5 was isolated from culture supernatant of wild-type E. faecalis strain OG1RF (TX4002); this form was apparently generated by cleavage of the Ser −1 -Leu 1 and Arg 230 -Leu 231 peptide bonds of the secreted zymogen. In contrast, the culture supernatant of the gelatinase-null mutant, TX5264, with a nonpolar deletion of gelE which encodes the E. faecalis gelatinase, was found to contain several forms of SprE proteolytically processed on both the N and C termini; in addition to a full-length zymogen and a truncated zymogen, three mature forms of the SprE proteinase, Leu 1 -Ala 237 , Ser −1 -Glu 227 , and Leu 1 -Glu 227 , were identified. As with the V8 proteinase of Staphylococcus aureus , the closest homologue of SprE, all of the active forms cleaved specifically Glu-Xaa peptide bonds but with substantially different efficiencies, while none was able to hydrolyze peptide bonds with Asp in the P1 position. The most active of all these enzyme forms against several substrates, including human fibrinogen and β-chain insulin, was the Ser −1 -Glu 227 ( −1 S-SprE) isolated from TX5264; −1 S-SprE, in contrast to other forms of SprE, was unstable at 37°C, apparently due to autodegradation. In conclusion, our results demonstrate that sprE encodes a highly specific serine-type glutamyl endopeptidase, the maturation of which is dependent on the presence of gelatinase. In the absence of gelatinase activity, the aberrant processing of pro-SprE results in the appearance of a “superactive” form of the enzyme, −1 S-SprE.

Vancomycin-resistant enterococci (VRE) have recently become an increasing problem in hospitals in Poland, being responsible for a growing number of nosocomial outbreaks. In this work, we have analyzed the second outbreak of VRE with the VanB phenotype to be identified in the country. It was caused by clonal dissemination of a single strain of vancomycin-resistant Enterococcus faecalis (VRES) and horizontal transmission of vancomycin resistance genes among several vancomycin-resistant Enterococcus faecium (VREM) strains. Two similar restriction fragment length polymorphism types of the vanB gene cluster characterized VRES and VREM isolates, and they both contained the same vanB2 variant of the vanB gene. Two vancomycin-susceptible E. faecium (VSEM) isolates, recovered from the same wards during the outbreak, proved to be related to certain VREM isolates and could represent endemic strains that had acquired vancomycin resistance. One VSEM and four VREM isolates, all identified in the same patient, belonged to a single clone, although they revealed remarkable diversity in terms of susceptibility, PFGE patterns, plasmid content, and number of vanB gene cluster copies. Most probably they reflected the dynamic evolution of an E. faecium strain in the course of infection of a single patient. One of the VREM isolates turned out to be resistant to teicoplanin, which coincided with the use of this antibiotic in the patient's therapy. Its vanB gene variant differed by a single mutation from that found in other isolates; however, it also lacked a large part of the vanB gene cluster, including the regulatory genes vanR B and - S B , and the vancomycin-inducible promoter P YB . Expression of the resistance genes vanH B , - B , and - X B was constitutive in the mutant, and this phenomenon was responsible for its unusual phenotype.

SummaryCaspase-mediated inflammatory cell death acts as an intrinsic defense mechanism against infection. Bacterial pathogens deploy countermeasures against inflammatory cell death, but the mechanisms by which they do this remain largely unclear. In a screen for Shigella flexneri effectors that regulate cell death during infection, we discovered that Shigella infection induced acute inflammatory, caspase-4-dependent epithelial cell death, which is counteracted by the bacterial OspC3 effector. OspC3 interacts with the caspase-4-p19 subunit and inhibits its activation by preventing caspase-4-p19 and caspase-4-p10 heterodimerization by depositing the conserved OspC3 X1-Y-X2-D-X3 motif at the putative catalytic pocket of caspase-4. Infection of guinea pigs with a Shigella ospC3-deficient mutant resulted in enhanced inflammatory cell death and associated symptoms, correlating with decreased bacterial burdens. Salmonella Typhimurium and enteropathogenic Escherichia coli infection also induced caspase-4-dependent epithelial death. These findings highlight the importance of caspase-4-dependent innate immune responses and demonstrate that Shigella delivers a caspase-4-specific inhibitor to delay epithelial cell death and promote infection.

SummarySelective autophagy of bacterial pathogens represents a host innate immune mechanism. Selective autophagy has been characterized on the basis of distinct cargo receptors but the mechanisms by which different cargo receptors are targeted for autophagic degradation remain unclear. In this study we identified a highly conserved Tectonin domain-containing protein, Tecpr1, as an Atg5 binding partner that colocalized with Atg5 at Shigella-containing phagophores. Tecpr1 activity is necessary for efficient autophagic targeting of bacteria, but has no effect on rapamycin- or starvation-induced canonical autophagy. Tecpr1 interacts with WIPI-2, a yeast Atg18 homolog and PI(3)P-interacting protein required for phagophore formation, and they colocalize to phagophores. Although Tecpr1-deficient mice appear normal, Tecpr1-deficient MEFs were defective for selective autophagy and supported increased intracellular multiplication of Shigella. Further, depolarized mitochondria and misfolded protein aggregates accumulated in the Tecpr1-knockout MEFs. Thus, we identify a Tecpr1-dependent pathway as important in targeting bacterial pathogens for selective autophagy.