Mismatch Repair–Independent Increase in Spontaneous Mutagenesis in Yeast Lacking Non-Essential Subunits of DNA Polymerase ε

Yeast DNA polymerase ε (Pol ε) is a highly accurate and processive enzyme that participates in nuclear DNA replication of the leading strand template. In addition to a large subunit (Pol2) harboring the polymerase and proofreading exonuclease active sites, Pol ε also has one essential subunit (Dpb2) and two smaller, non-essential subunits (Dpb3 and Dpb4) whose functions are not fully understood. To probe the functions of Dpb3 and Dpb4, here we investigate the consequences of their absence on the biochemical properties of Pol ε in vitro and on genome stability in vivo. The fidelity of DNA synthesis in vitro by purified Pol2/Dpb2, i.e. lacking Dpb3 and Dpb4, is comparable to the four-subunit Pol ε holoenzyme. Nonetheless, deletion of DPB3 and DPB4 elevates spontaneous frameshift and base substitution rates in vivo, to the same extent as the loss of Pol ε proofreading activity in a pol2-4 strain. In contrast to pol2-4, however, the dpb3Δdpb4Δ does not lead to a synergistic increase of mutation rates with defects in DNA mismatch repair. The increased mutation rate in dpb3Δdpb4Δ strains is partly dependent on REV3, as well as the proofreading capacity of Pol δ. Finally, biochemical studies demonstrate that the absence of Dpb3 and Dpb4 destabilizes the interaction between Pol ε and the template DNA during processive DNA synthesis and during processive 3′ to 5′exonucleolytic degradation of DNA. Collectively, these data suggest a model wherein Dpb3 and Dpb4 do not directly influence replication fidelity per se, but rather contribute to normal replication fork progression. In their absence, a defective replisome may more frequently leave gaps on the leading strand that are eventually filled by Pol ζ or Pol δ, in a post-replication process that generates errors not corrected by the DNA mismatch repair system

Coal-fired tile stoves: Efficiency and emissions

Coal-fired tile stoves are widely used in Poland for domestic heating. These massive stoves,are fired for short periods once or twice each day, and the stored heat is slowly released into the room by natural convection Low-quality coal is typically used, and these stoves are therefore a major source of air pollution. A facility has been constructed to study the efficiency and emissions characteristics of these stoves. Stove exhaust gas is directed into a dilution tunnel in which pollutant concentrations and emission rates are measured. Efficiency is determined using a heat loss method. In baseline tests, stove efficiencies were found to be higher than expected -- 60% to 65%. Emission factors are high for particulates, carbon monoxide (CO), and organics. Low-volatility ``smokeless fuels`` were tested as an alternative to the normal fuels. Using the normal operating procedure, these were found to yield a factor of 10 reduction in particulate emissions but a 50% increase in CO emissions. A new operating procedure was developed with these fuels in which CO levels were lower than with the normal fuel and efficiency increased to 70%. These smokeless fuels are seen as attractive options for improving regional air quality, partly because their use does not require capital investment by residents

Potencjalna aplikacja metody obrotowo-udarowej w otworach za gazem łupkowym w rejonie Basenu Podlaskiego

The following work presents investigation of possible drilling of overburden rocks, right above the gas reservoir, in shale rock formations with potential application of rotary-percussion drilling method in Podlasie Basin region. Extensive description of lithology of shale rocks together with their age, maturity of the organic matter and thickness of particular layers have been presented. Due to different thickness of formations, the depths of layers are not indicated, as it would be too big of approximation. Variously scaled and averaged thickness of particular formation layers was given in order to maintain maximum transparency of the paper. It should be noted that the formation rocks of the Devonian as well as Carboniferous period do not occur in all profiles of the Paleozoic period of the Podlasie Basin but only in the south-western part of the basin. Locally occurring (i.e. on the south-eastern border of the Podlasie basin) layers of the Devonian and Carboniferous period were omitted. A stratigraphic profile with preserved proportions between the average thicknesses of particular formation layers was constructed and presented in latter part of the research paper. The research carried out in this paper was complemented with estimates of Polish shale gas resources. The Baltic Basin region is by far most prospective area for shale gas exploitation when it comes to documented as well as undocumented resources. The areas of Podlasie as well as Lublin Basins are second and third most rich areas of this resource. Percussion-rotary drilling method enables for much higher penetration rates using similar weight on bit and rotational speed as in standard rotary drilling method. Following papers answers questions such as: under what conditions application of percussion-rotary technique is possible or what drilling fluids are the most suitable for such method. The percussion-rotary drilling method not only guarantees faster drilling but also leaves borehole much more straight and without unnecessary dog legs. Drilling rig and down hole equipment used for percussion-rotary drilling method takes much less space in comparison with standard rotary rigs for deep drilling and could be potentially implemented for drilling shale gas wells in Podlasie Basin region.Poniższa praca przedstawia badania nad potencjalnym wykorzystaniem metody udarowo-obrotowej w celu wiercenia formacji skalnych występujących tuż nad pokładami złóż gazu łupkowego w rejonie basenu podlaskiego. W poniższym artykule została przeprowadzona analiza skał łupkowych wraz z ich wiekiem, dojrzałością materii organicznej oraz miąższością poszczególnych warstw. Na skutek dość zróżnicowanej miąższości formacji skalnych, głębokość zalegania warstw nie została określona z powodu dużego błędu przy uśrednieniu ich wartości. Wyskalowane oraz uśrednione miąższości zostały przedstawiono w celu utrzymania spójności i przejrzystości pracy. Należy nadmienić, że formacje skalne z okresu dewońskiego oraz karbońskiego nie występują we wszystkich profilach z okresu paleozoiku basenu podlaskiego, a jedynie w jego południowo-zachodnich częściach. Pominięto lokalnie występujące (tj. na południowo-wschodniej granicy) warstwy dewońskie oraz karbońskie. Profil litostratygraficzny z zachowanymi proporcjami pomiędzy średnimi miąższościami poszczególnych warstw skalnych został skonstruowany oraz przedstawiony w końcowej części pracy. Badania w poniższym artykule zostały dodatkowo uzupełnione danymi szacunkowymi zasobów gazu łupkowego na terenie Polski. Obszar basenu bałtyckiego jest obecnie najbardziej lukratywny pod względem wydobycia gazu ze skał łupkowych z powodu dużej ilości udokumentowanych oraz jeszcze nierozpoznanych złóż tego surowca. Obszary basenu podlaskiego oraz lubelskiego są drugie oraz trzecie w kolejności pod względem ilości zasobów gazu łupkowego na terenie Polski. Metoda udarowo-obrotowa pozwala na dużo szybsze zwiercanie formacji skalnych przy użyciu podobnych parametrów mechanicznych takich jak nacisk na świder i prędkość obrotowa niż przy standardowym procesie wiercenia metodą obrotową. Poniższy artykuł odpowiada na pytania takie jak: w jakich warunkach możliwe jest wiercenie metodą udarowo-obrotową oraz jakie rodzaje płuczek wiertniczych są najbardziej odpowiednie do wiercenia taką techniką. Metoda udarowo-obrotowa zapewnia nie tylko dużo większy postęp wiertniczy, ale również dużo mniejsze odchylenia od osi otworu oraz zapobiega nagłym zmianom kierunku podczas procesu wiercenia. Wiertnica oraz osprzęt zapuszczany do otworu stosowany podczas wiercenia metodą udarowo-obrotową zajmuje znacznie dużo mniej miejsca w porównaniu z głębokimi wierceniami konwencjonalnymi metodami. Dzięki wspomnianym zaletom metoda udarowo-obrotowa może zostać potencjalnie wykorzystana przy wierceniu otworów za gazem łupkowym w obszarze basenu podlaskiego

The analysis of heating output evaluation methods for borehole heat exchangers

Projects involving borehole heat exchangers more often need to undergo a series of tests before implementation. Inserted pipes and cement in the borehole may have diff erent thermal properties. Until recently, such values were determined in approximate, based on values taken from the literature. Special methods are used more often to perform this type of work in order to correctly determine the properties of a borehole heat exchanger. The aim of the study was to present an analysis of thermal properties of borehole heat exchangers with the main emphasis on parameters such as thermal conductivity and thermal resistance. The analyzed data was obtained through the use of three methods:– analysis of the lithological profi le with rock conductivity based on the literature,– analysis of natural temperature profi le in aborehole heat exchanger (logger NIMO-T),– thermal response test

Identification of groundwater contributions to streamflow in a medium size catchment

Interactions between the groundwater and surface water affect the qualitative and quantitative status of water resources. Estimation of the fluxes and the associated loadings of contaminants exchanged between the aquifers and river reaches is an important but still not well recognized component of water resources management. Such estimates are available from the numerical models of flow and transport, however, coupling of the groundwater and surface water model domains is difficult. Calibration of the coupled models relies on the knowledge of the exchanged water fluxes, hydraulic conductivities of riverbed sediments and of other parameters. Preliminary application methods allowing for identification and quantification of the groundwater – surface water exchange is presented for the Kocinka catchment in Southern Poland

A study of hydraulic characteristic for borehole heat exchangers

Thermal Response Test (TRT) is a standard test performed in borehole heat exchangers (BHE), which provides thorough understanding of thermal parameters of surrounding rock mass. Following work consists of calculations for hydraulic power and pressure losses along the BHE’s length. Analysis was carried out in eight BHE’s with different diameters, lengths and heat carriers in various areas throughout Poland. In accordance with TRT results, potential power exchanged between BHE and rock mass was determined. In order to find relations between pressure losses and volumetric flow rate, hydraulic tests in average static temperature of rock mass and during heating period were investigated. Proportions between hydraulic power and total power exchange with rock mass are also presented in following research