Return to the city

Attempts to revolutionize the spatial structure of Wroclaw emerged in the early twentieth century. Max Berg introduced, in the years 1919 -1925, redevelopment plan of the city center involving the demolition of inter-market buildings and introduction of modern skyscrapers which are based on the American model of high buildings of the city from the late nineteenth century. Ernst May postulated the decentralization of Wroclaw by building a grid of the satellite districts for 50 to 100 thousand inhabitants, acting as independent towns with their own administrative, economic and cultural services. Adolf Rading in his visions expanded Wroclaw linearly adjusting the shape of the city to the course of the Odra River and the main rail-road trail. Expansion - intense urban sprawl - began to realize half a century later. Bedroom suburbs of metropolis started to surround Wroclaw, without adequate facilities and links with the city. The chaotic development model of urban agglomeration was in conflict with thoughtful assumptions formed half-century ago. In the nineties, together with the political economic and social transformation, buildings in Wroclaw were intensively built. These were mostly single-family houses. Sprawl, as previously global phenomenon, has now become a nationwide problem. Some residents, tempted by attractions of suburban house, moved out of the city. It took only two decades that enthusiasm waned. Reality and sociological studies have begun to argue that this model of functioning, without the execution of all elements of the spatial model surrounded by the satellite housing estates (mainly communication connections) is not optimal. The latest concepts of development of Wroclaw assume a "return to the city" and making better use of its urban potential. A few peripheral districts of the city try to be subjected to activation and revitalization, aiming at creating there new identity, remaining well connected to the city center. This is achieved, among others, by the creation of local centers with markets, using the tradition of places. These are mainly: Psie Pole, Leœnica and Brochów. An interesting experience also seems to be the implementation of the new WUWA on Zerniki. The analysis of the indicated cases can formulate initial conclusions concerning the reasonableness and attractiveness of "back to the city"

Emission of Polychlorinated Dibenzo-p-Dioxins (PCDDs) and Polychlorinated Dibenzofurans (PCDFs) from Underfiring System of Coke Oven Battery

A coke oven battery is not considered as a significant source of PCDDs/PCDFs emissions; however, due to small amounts of chlorine in coal dioxins, dibenzofurans may be formed. The paper presents the attempts to determine the level of emission of PCDDs/PCDFs from the COB underfiring system and to confront the obtained results with the calculations based on the mass balance of chlorine in the coking process and reactions of both chlorophenols formation and PCDDs and PCDFs formation from mono- and polychlorophenols. There were PCDDs/PCDFs concentrations measured in flue gases from the underfiring system of two COBs at a Polish coking plant. The measurements included both an old and a new battery. The obtained concentrations of PCDDs/PCDFs were lower than reported in the literature (0.5-1.7 ng I-TEQ/tcoke), while the results for old COB were on average 3 times higher than for the new one. It was found that PCDD/F emission from COB underfiring system is insignificant and that PCDDs/PCDFs formation during coal coking should consider the mechanisms of their formation from mono- and polychlorophenols, as well as the influence of process parameters on the synthesis

Czynnik wzrostu śródbłonka naczyniowego i jego receptory w ścianie żylaków kończyn

Background. Disturbances in the regulation of vessel wall homeostasis are a potential factor initiating varicose vein development. Vascular endothelial growth factor A (VEGF-A) may play a hypothetic role in this process. The aim of the study was to evaluate mRNA expression and protein content of VEGF-A and its receptors (VEGF R1, VEGF R2) in varicose veins and varicose veins complicated by thrombophlebitis. Material and methods. Walls of varicose veins and varicose veins complicated by thrombophlebitis were the studied material. Walls of normal saphenous veins, which were harvested from patients with chronic limb ischaemia undergoing infrainguinal by-pass grafting, were the control material. The RT-PCR method was employed to assess mRNA expression of VEGF-A and its receptors, whereas the ELISA method was used to evaluate contents of VEGF-A and its receptors. Results. VEGF-A and VEGF R2 mRNA expression is increased, whereas VEGF R1 mRNA expression is unchanged in the wall of varicose veins in comparison with the wall of normal ones. VEGF-A and VEGF R1 mRNA expression is increased in the wall of varicose veins complicated by thrombophlebitis in comparison with walls of normal and varicose veins. VEGF R2 mRNA expression is also increased in the wall of varicose veins complicated by thrombophlebitis in comparison with control veins, but it is comparable to that in the wall of varicose veins. Changes in mRNA expression are correlated with appropriate changes in protein contents of VEGF-A, VEGF R1, and VEGF R2. Conclusions. The demonstrated changes in mRNA expression, as well as in the contents of VEGF-A, VEGF R1, and VEGF R2, in the wall of varicose veins may be accepted as one of the reasons for the clinical symptoms of the disease and can predispose to its progression. Acta Angiol 2011; 17, 2: 141–149Wstęp. Zaburzenia regulacji homeostazy ściany naczyniowej są potencjalnym czynnikiem inicjującym rozwój żylaków kończyn. Hipotetyczną rolę w tym procesie może odgrywać czynnik wzrostu śródbłonka naczyniowego A (VEGF-A). Celem pracy była ocena ekspresji mRNA i zawartości VEGF-A oraz jego receptorów (VEGF R1, VEGF R2) w ścianie żylaków niepowikłanych i żylaków powikłanych zakrzepowym zapaleniem. Materiał i metody. Materiałem badanym były ściany żylaków niepowikłanych i żylaków w stanie zakrzepowego zapalenia. Materiałem kontrolnym były ściany prawidłowych żył odpiszczelowych, pobrane od chorych na przewlekłe niedokrwienie kończyn, u których wykonano zabieg pomostowania udowo-podkolanowego. Na podstawie metody reakcji polimerazy łańcuchowej w połączeniu z odwrotną transkrypcją (RT-PCR) oceniono ekspresję mRNA VEGF-A i jego receptorów, natomiast wykorzystując metodę ELISA, zbadano zawartość VEGF-A i jego receptorów. Wyniki. W ścianie żylaków w porównaniu ze ścianą żył prawidłowych ekspresja VEGF-A mRNA oraz VEGF R2 mRNA jest większa, podczas gdy ekspresja VEGF R1 mRNA nie ulega istotnym zmianom. W ścianie żylaków powikłanych zakrzepowym zapaleniem ekspresja VEGF-A mRNA i VEGF R1 mRNA jest większa w porównaniu ze ścianą żył prawidłowych i ścianą żylaków niepowikłanych. Natomiast ekspresja VEGF R2 mRNA jest również większa niż w ścianie żył prawidłowych, ale porównywalna z ekspresją w ścianie żylaków niepowikłanych. Zmianom w ekspresji mRNA odpowiadają zmiany w zawartości białka VEGF-A, VEGF R1 i VEGF R2 w ścianie żylnej. Wnioski. Wykazane zmiany w ekspresji mRNA i zawartości VEGF-A, VEGF R1 i VEGF R2 w ścianie żylaków kończyn mogą być jedną z przyczyn objawów klinicznych choroby oraz predysponować do jej postępu. Acta Angiol 2011; 17, 2: 141–14