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  • Author: Grzegorz Cieślak x
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Grzegorz Cieślak and Maria Trzaska

Abstract

The paper presents results of studies of composite nickel/graphene coatings produced by electrodeposition method on a steel substrate. The method of producing composite coatings with nanocrystalline nickel matrix and dispersion phase in the form of graphene is presented. For comparative purposes, the study also includes nano-crystalline Ni coatings produced by electrochemical reduction without built-in graphene flakes. Graphene was characterized by Raman spectroscopy, transmission and scanning electron microscopes. Results of studies on the structure and morphology of Ni and Ni/graphene layers produced in a bath containing different amounts of graphene are presented. Material of the coatings was characterized by SEM, light microscopy, X-ray diffraction. The microhardness of the coatings was examined by Knoop measurements. The adhesion of the coatings with the substrate was tested using a scratchtester. The influence of graphene on the structure and properties of composite coatings deposited from a bath with different graphene contents was determined.

Open access

Wojciech Paul, Elżbieta Cieślak, Michał Ronikier, Grzegorz Migdałek, Aneta Słomka and Justyna Żabicka

Abstract

Viola uliginosa (bog violet) is a declining species throughout its range due to – mostly anthropogenic – drying out of the wet habitats it occupies. Using AFLP markers, we aimed to estimate the genetic diversity in Polish populations, that may give an insight into the situation of plant populations facing rapid loss of natural habitats.

Bog violet from several dispersed Polish populations is generally characterized by very low genetic diversity (H T = 0.048), even lower than several other endangered violets; therefore, we suggest that it should preserve at least EN rank in the red lists/red data books. The mean gene diversity within all populations (H S) was much lower than gene diversity (G ST) between populations (0.020 versus 0.583, respectively) which supports the prevalence of clonal propagation of the species (mainly by stolons) but may also point to some significance of autogamy in cleisto- and chasmogamous flowers. A high F ST value and the Mantel test for all populations revealed significant isolation by distance. Geographically neighboring pairs of populations formed genetic clusters supported by all (in the case of two closest populations) or most statistical analyses applied. Special attention should be paid to the locus classicus of the species in Rząska, consisting of a small number of individuals, forming a genetically distinct group, revealing very low gene diversity (H j = 0.009) and the longest genetic distance to the remaining populations. Our results can contribute to planning future protection measures for the species at this and other locations. Genetic structure of the studied populations suggests local affinities of populations but does not generally support hypothesized recent continuity of V. uliginosa range along the river valleys of southern Poland; this view may, however, be altered with widening of the scope of studied populations and chosen molecular markers.

Open access

Agnieszka Grabias, Viktoriia Basykh, Jarosław Ferenc, Grzegorz Cieślak, Tadeusz Kulik and Michał Kopcewicz

Abstract

Nanocrystalline Fe80-x-yCoxNiyCu1Nb3Si4B12 alloys were prepared by the annealing of amorphous ribbons. Primary crystallization of the alloys annealed at temperatures of between 500 and 550°C was studied by X-ray diffraction and Mössbauer spectroscopy. Magnetic properties of the alloys were investigated using a hysteresis loop tracer and vibrating sample magnetometer. The annealed ribbons are composed of a two-phase nanostructure consisting of bcc Fe-based grains embedded in an amorphous matrix. Conversion electron Mössbauer spectroscopy (CEMS) measurements reveal a more advanced crystallization process in the surface layers when compared with the volume of the ribbons. The degree of saturation magnetization of the nanocrystalline alloys is of about 1.5 T. The coercive field varies from 1.0 to 6.5 A/m and peaks at an annealing temperature of 525°C. Magnetic softening of the nanocrystalline alloys observed after annealing at 550°C is correlated with a volume fraction of the nanocrystalline bcc phase.

Open access

Marek Krawczyk, Michał Grąt, Karolina Grąt, Karolina Wronka, Maciej Krasnodębski, Jan Stypułkowski, Łukasz Masior, Wacław Hołówko, Joanna Ligocka, Paweł Nyckowski, Tadeusz Wróblewski, Rafał Paluszkiewicz, Waldemar Patkowski, Krzysztof Zieniewicz, Leszek Pączek, Piotr Milkiewicz, Urszula Ołdakowska-Jedynak, Bogusław Najnigier, Krzysztof Dudek, Piotr Remiszewski, Ireneusz Grzelak, Oskar Kornasiewicz, Marcin Kotulski, Piotr Smoter, Mariusz Grodzicki, Michał Korba, Piotr Kalinowski, Michał Skalski, Krzysztof Zając, Rafał Stankiewicz, Marta Przybysz, Bartosz Cieślak, Łukasz Nazarewski, Małgorzata Nowosad, Konrad Kobryń, Michał Wasilewicz, Joanna Raszeja-Wyszomirska, Jolanta Piwowarska, Dorota Giercuszkiewicz, Joanna Sańko-Resmer, Sławomir Rejowski, Monika Szydłowska-Jakimiuk, Barbara Górnicka, Bogna Wróblewska-Ziarkiewicz, Michał Mazurkiewicz, Grzegorz Niewiński, Jacek Pawlak and Ryszard Pacho

Abstract

Liver transplantation is a well-established treatment of patients with end-stage liver disease and selected liver tumors. Remarkable progress has been made over the last years concerning nearly all of its aspects.

The aim of this study was to evaluate the evolution of long-term outcomes after liver transplantations performed in the Department of General, Transplant and Liver Surgery (Medical University of Warsaw).

Material and methods. Data of 1500 liver transplantations performed between 1989 and 2014 were retrospectively analyzed. Transplantations were divided into 3 groups: group 1 including first 500 operations, group 2 including subsequent 500, and group 3 comprising the most recent 500. Five year overall and graft survival were set as outcome measures.

Results. Increased number of transplantations performed at the site was associated with increased age of the recipients (p<0.001) and donors (p<0.001), increased rate of male recipients (p<0.001), and increased rate of piggyback operations (p<0.001), and decreased MELD (p<0.001), as well as decreased blood (p=0.006) and plasma (p<0.001) transfusions. Overall survival was 71.6% at 5 years in group 1, 74.5% at 5 years in group 2, and 85% at 2.9 years in group 3 (p=0.008). Improvement of overall survival was particularly observed for primary transplantations (p=0.004). Increased graft survival rates did not reach the level of significance (p=0.136).

Conclusions. Long-term outcomes after liver transplantations performed in the Department of General, Transplant and Liver Surgery are comparable to those achieved in the largest transplant centers worldwide and are continuously improving despite increasing recipient age and wider utilization of organs procured from older donors.

Open access

Marek Krawczyk, Michał Grąt, Krzysztof Barski, Joanna Ligocka, Arkadiusz Antczak, Oskar Kornasiewicz, Michał Skalski, Waldemar Patkowski, Paweł Nyckowski, Krzysztof Zieniewicz, Ireneusz Grzelak, Jacek Pawlak, Abdulsalam Alsharabi, Tadeusz Wróblewski, Rafał Paluszkiewicz, Bogusław Najnigier, Krzysztof Dudek, Piotr Remiszewski, Piotr Smoter, Mariusz Grodzicki, Michał Korba, Marcin Kotulski, Bartosz Cieślak, Piotr Kalinowski, Piotr Gierej, Mariusz Frączek, Łukasz Rdzanek, Rafał Stankiewicz, Konrad Kobryń, Łukasz Nazarewski, Dorota Leonowicz, Magdalena Urban-Lechowicz, Anna Skwarek, Dorota Giercuszkiewicz, Agata Paczkowska, Jolanta Piwowarska, Remigiusz Gelo, Paweł Andruszkiewicz, Anna Brudkowska, Renata Andrzejewska, Grzegorz Niewiński, Beata Kilińska, Aleksandra Zarzycka, Robert Nowak, Cezary Kosiński, Teresa Korta, Urszula Ołdakowska-Jedynak, Joanna Sańko-Resmer, Bartosz Foroncewicz, Jacek Ziółkowski, Krzysztof Mucha, Grzegorz Senatorski, Leszek Pączek, Andrzej Habior, Robert Lechowicz, Sławomir Polański, Elżbieta Leowska, Ryszard Pacho, Małgorzata Andrzejewska, Olgierd Rowiński, Sławomir Kozieł, Jerzy Żurakowski, Bogna Ziarkiewicz-Wróblewska, Barbara Górnicka, Piotr Hevelke, Bogdan Michałowicz, Andrzej Karwowski and Jerzy Szczerbań

1000 Liver Transplantations at the Department of General, Transplant and Liver Surgery, Medical University of Warsaw - Analysis of Indications and Results

The aim of the study was to analyze indications and results of the first one thousand liver transplantations at Chair and Clinic of General, Transplantation and Liver Surgery, Medical University of Warsaw.

Material and methods. Data from 1000 transplantations (944 patients) performed at Chair and Clinic of General, Transplantation and Liver Surgery between 1994 and 2011 were analyzed retrospectively. These included 943 first transplantations and 55 retransplantations and 2 re-retransplantations. Frequency of particular indications for first transplantation and retransplantations was established. Perioperative mortality was defined as death within 30 days after the transplantation. Kaplan-Meier survival analysis was used to estimate 5-year patient and graft survival.

Results. The most common indications for first transplantation included: liver failure caused by hepatitis C infection (27.8%) and hepatitis B infection (18%) and alcoholic liver disease (17.7%). Early (< 6 months) and late (> 6 months) retransplantations were dominated by hepatic artery thrombosis (54.3%) and recurrence of the underlying disease (45%). Perioperative mortality rate was 8.9% for first transplantations and 34.5% for retransplantations. Five-year patient and graft survival rate was 74.3% and 71%, respectively, after first transplantations and 54.7% and 52.9%, respectively, after retransplantations.

Conclusions. Development of liver transplantation program provided more than 1000 transplantations and excellent long-term results. Liver failure caused by hepatitis C and B infections remains the most common cause of liver transplantation and structure of other indications is consistent with European data.