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Mariusz Gła̢bowski, Bartosz Musznicki, Przemysław Nowak and Piotr Zwierzykowski

Abstract

The Ant Colony Optimization (ACO) metaheuristic is a versatile algorithmic optimization approach based on the observation of the behaviour of ants. As a result of numerous analyses, ACO has been applied to solving various combinatorial problems. The ant colony metaheuristic proves itself to be efficient in solving NP-hard problems, often generating the best solution in the shortest amount of time. However, not enough attention has been paid to ACO as a means of solving problems that have optimal solutions which can be found using other methods.

The shortest path problem is undoubtedly one of the aspects of great significance to navigation and telecommunications. It is used, amongst others, for determining the shortest route between two geographical locations, for routing in packet networks, and to balance and optimize network utilization. Thus, this article introduces ShortestPathACO, an Ant Colony Optimization based algorithm designed to find the shortest path in a graph. The algorithm consists of several subproblems that are presented successively. Each subproblem is discussed from many points of view to enable researchers to find the most suitable solutions to the problems they investigate.

Open access

Dorota Nowak-Woźny, Wojciech Moroń, Bartosz Urbanek and Wiesław Rybak

Abstract

The paper presents the results of the mechanical, electrical, CCSEM and XRD measurements of hard coal, conducted in simulated conditions of sintering in atmospheres of O2/CO2,. The changes of the coal ash resistivity are correlated with the content of the oxides and with the sintering temperature determined by the mechanical test and Leitz method. The SEM-EDS analysis was conducted for deposits on the probe. The changes of the measured ash samples, observed during sintering process in O2/CO2 atmosphere, were discussed in the ash microstructure point of view.

Open access

Bartosz Nowak, Katarzyna Korszun-Kłak and Urszula Zielonka

Abstract

The aim of this work was to identify concentration levels of different chemical forms of mercury (TGM, TPM) in the ambient air in selected areas of the Silesian Region, characterized by low and high mercury emission. Based on the obtained data TGM and TPM concentration levels were determined. The project also focused on determination of dry and wet deposition of mercury compounds. Data concerning TGM and TPM flux rates in the ambient air and data on mercury deposition were used to determine a deposition coefficient. The coefficient was calculated as a share of mercury deposition on the land surface (dry and wet) to the amount of this contaminant transported with loads of air in the form of TGM and TPM in a given measurement station. At both monitoring stations the deposition coefficient did not exceed 0.2 %. The idea of calculating the deposition coefficient based on the analysis of TGM and TPM flux rate is a new solution. The proposed deposition coefficient allows to quantify information on a selected contaminant concentration and its potential impact resulting from deposition. Further studies on the deposition coefficient may contribute to the development of methods for estimating the impact of contaminants contained in the ambient air on other environmental components based on the analyses of the contaminant flux rate.

Open access

Janusz A. Madej, Jan P. Madej, Piotr Dzięgiel, Bartosz Puła and Marcin Nowak

Abstract

The study aimed to demonstrate the expression of hypoxia-inducible factor (HIF-1α) in soft tissue mesenchymal tumours (fibroma and fibrosarcoma) in dogs. An attempt was made to correlate the obtained results with density of blood vessels (expression of von Willebrand Factor, vWF), expression of Ki-67 proliferation antigen, and with intensity of apoptosis in studied tumours. The study was performed on paraffin sections of 15 fibromas and 40 fibrosarcomas sampled from 55 female dogs aged 6 to 16 years. Immunohistochemical staining against HIF-1α, vWF, and Ki-67 was performed. Apoptosis was detected with the use of TUNEL reaction. A significantly higher HIF-1α expression was noted in fibrosarcomas in comparison to fibromas (P < 0.0001). HIF-1α expression in fibromas manifested strong positive correlation with tumour vascularity (r = 0.67, P = 0.007). Moreover, HIF-1α expression in fibrosarcomas manifested a moderate positive correlation with tumour malignancy grade (r = 0.44, P = 0.004), tumour vascularity (r = 0.52, P < 0.001), Ki-67 antigen expression (r = 0.42; P = 0.007), and TUNELpositive cells (r = 0.37, P = 0.017). Expression of HIF-1α was detected in 86.7% of fibroma type tumours and in 100% of fibrosarcomas. In all studied tumours expression of HIF-1α manifested positive correlation with the density of blood vessels, and in fibrosarcomas it correlated also with malignancy grade, intensity of Ki-67 expression, and with intensity of apoptosis in tumour cells.

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.