Generalized Contour Dynamics: A Review

Contour dynamics is a computational technique to solve for the motion of vortices in incompressible inviscid flow. It is a Lagrangian technique in which the motion of contours is followed, and the velocity field moving the contours can be computed as integrals along the contours. Its best-known examples are in two dimensions, for which the vorticity between contours is taken to be constant and the vortices are vortex patches, and in axisymmetric flow for which the vorticity varies linearly with distance from the axis of symmetry. This review discusses generalizations that incorporate additional physics, in particular, buoyancy effects and magnetic fields, that take specific forms inside the vortices and preserve the contour dynamics structure. The extra physics can lead to time-dependent vortex sheets on the boundaries, whose evolution must be computed as part of the problem. The non-Boussinesq case, in which density differences can be important, leads to a coupled system for the evolution of both mean interfacial velocity and vortex sheet strength. Helical geometry is also discussed, in which two quantities are materially conserved and whose evolution governs the flow

Aerobic Training in Rats Increases Skeletal Muscle Sphingomyelinase and Serine Palmitoyltransferase Activity, While Decreasing Ceramidase Activity

Sphingolipids are important components of cell membranes that may also serve as cell signaling molecules; ceramide plays a central role in sphingolipid metabolism. The aim of this study was to examine the effect of 5 weeks of aerobic training on key enzymes and intermediates of ceramide metabolism in skeletal muscles. The experiments were carried out on rats divided into two groups: (1) sedentary and (2) trained for 5 weeks (on a treadmill). The activity of serine palmitoyltransferase (SPT), neutral and acid sphingomyelinase (nSMase and aSMase), neutral and alkaline ceramidases (nCDase and alCDase) and the content of sphingolipids was determined in three types of skeletal muscle. We also measured the fasting plasma insulin and glucose concentration for calculating HOMA-IR (homeostasis model assessment) for estimating insulin resistance. We found that the activities of aSMase and SPT increase in muscle in the trained group. These changes were followed by elevation in the content of sphinganine. The activities of both isoforms of ceramidase were reduced in muscle in the trained group. Although the activities of SPT and SMases increased and the activity of CDases decreased, the ceramide content did not change in any of the studied muscle. Although ceramide level did not change, we noticed increased insulin sensitivity in trained animals. It is concluded that training affects the activity of key enzymes of ceramide metabolism but also activates other metabolic pathways which affect ceramide metabolism in skeletal muscles

Different expressions of trypsin and chymotrypsin in relation to growth in Atlantic salmon (Salmo salar L.)

The expressions of trypsin and chymotrypsin in the pyloric caeca of Atlantic salmon (Salmo salar L.) were studied in three experiments. Two internal (trypsin phenotypes, life stages) and three common external factors (starvation, feeding, temperatures) influencing growth rates were varied. Growth was stimulated by increased temperature and higher feeding rate, and it was depressed during starvation. The interaction between trypsin phenotype and start-feeding temperature affected specific activity of trypsin, but not of chymotrypsin. Trypsin specific activity and the activity ratio of trypsin to chymotrypsin (T/C ratio) increased when growth was promoted. Chymotrypsin specific activity, on the other hand, increased when there was a reduction in growth rate whereas fish with higher growth had higher chymotrypsin specific activity resulting in lower T/C ratio value. During a rapid growth phase, trypsin specific activity did not correlate with chymotrypsin specific activity. On the other hand, a relationship between specific activities of trypsin and chymotrypsin could be observed when growth declined, such as during food deprivation. Trypsin is the sensitive key protease under conditions favouring growth and genetically and environmentally affected, while chymotrypsin plays a major role when growth is limited or depressed. Trypsin specific activity and the T/C ratio value are shown to be important factors in the digestion process affecting growth rate, and could be applicable as indicators for growth studies of fish in captive cultures and in the wild, especially when food consumption rate cannot be measured

Hepatoselective Nitric Oxide (NO) Donors, V-PYRRO/NO and V-PROLI/NO, in Nonalcoholic Fatty Liver Disease: A Comparison of Antisteatotic Effects with the Biotransformation and Pharmacokinetics

ABSTRACT V-PYRRO/NO [O(2)-vinyl-1-(pyrrolidin-1-yl)diazen-1-ium-1,2-diolate] and V-PROLI/NO (O2-vinyl-[2-(carboxylato)pyrrolidin-1-yl]diazen-1-ium-1,2-diolate), two structurally similar diazeniumdiolate derivatives, were designed as liver-selective prodrugs that are metabolized by cytochrome P450 isoenzymes, with subsequent release of nitric oxide (NO). Yet, their efficacy in the treatment of nonalcoholic fatty liver disease (NAFLD) and their comparative pharmacokinetic and metabolic profiles have not been characterized. The aim of the present work was to compare the effects of V-PYRRO/NO and V-PROLI/NO on liver steatosis, glucose tolerance, and liver fatty acid composition in C57BL/6J mice fed a high-fat diet, as well as to comprehensively characterize the ADME (absorption, distribution, metabolism and excretion) profiles of both NO donors. Despite their similar structure, V-PYRRO/NO and V-PROLI/NO showed differences in pharmacological efficacy in the murine model of NAFLD. V-PYRRO/NO, but not V-PROLI/NO, attenuated liver steatosis, improved glucose tolerance, and favorably modified fatty acid composition in the liver. Both compounds were characterized by rapid absorption following i.p. administration, rapid elimination from the body, and incomplete bioavailability. However, V-PYRRO/NO was eliminated mainly by the liver, whereas V-PROLI/NO was excreted mostly in unchanged form by the kidney. V-PYRRO/NO was metabolized by CYP2E1, CYP2C9, CYP1A2, and CYP3A4, whereas V-PROLI/NO was metabolized mainly by CYP1A2. Importantly, V-PYRRO/NO was a better NO releaser in vivo and in the isolated, perfused liver than V-PROLI/NO, an effect compatible with the superior antisteatotic activity of V-PYRRO/NO. In conclusion, V-PYRRO/NO displayed a pronounced antisteatotic effect associated with liver-targeted NO release, whereas V-PROLI/NO showed low effectiveness, was not taken up by the liver, and was eliminated mostly in unchanged form by the kidney

Radiometryczne określenie stopnia dekontaminacji mikrobiologicznej powierzchni roboczych stosowanych w przemyśle spożywczym

Bacteria ³² P were used to determine cleanability of various surfaces ised in food industries. Surfaces made of plastics, tephlon in particular, had the highest cleanability level as compared with those of steel or aluminium.Przebadana została zmywalność mikroorganizmów z różnych rodzajów powierzchni roboczych przy użyciu bakterii zawierających ³²P. Znakowanie komórek przeprowadzono przez dodanie KH₂³²PO₄ do płynnego podłoża. Po inkubacji, hodowle B. subtilis, S. aureus i P. vulgaris odwirowywano wielokrotnie w 0,85% NaCl lub 0,01% LiCl w celu usunięcia nadmiaru izotopu, a następnie nanoszono na powierzchnie robocze. Pomiary radioaktywności powierzchni wykonywano przed i po zabiegu mycia w powtarzalnych warunkach. Spośród wymienionych gatunków bakterii najłatwiejszy do zmywania okazał się P. vulgaris, niezależnie od zastosowanego nośnika i rodzaju powierzchni roboczej. Najłatwiejszą powierzchnią do zmywania okazał się teflon, najtrudniej zaś usuwano bakterie z powierzchni metalowych, niezależnie od stopnia ich chropowatości (tab. 4). Różnice w łatwości zmywania pomiędzy B. subtilis i S. aureus oraz P. vulgaris i B. subtilis powodowane były także zastosowanym nośnikiem (tab. 3). Wyniki oznaczeń radiometrycznych wykazały, że na powierzchniach roboczych znajdowały się bakterie nawet wtedy, gdy uzyskiwano negatywne rezultaty oznaczeń mikrobiologicznych (tab 1). Wskazuje to na większą przydatność opisywanej metody niż metod konwencjonalnych w badaniach nad mechanizmami procesów dekontaminacyjnych. Fotografie wykonane techniką mikroskopii elektronowej wskazują na możliwość stawiania odmiennego oporu czynnikowi myjącemu przez bakterie i potwierdzają jednocześnie wyniki radiometryczne

Effect of Refurbished Thermal Insulation of Exterior Partitions in a Building on the Primary Energy and the Air Pollutant Emission Factors

The paper contains an analysis of a multi-flat building located in Lębork. The calculations made for the existing building as required to issue an energy performance certificate demonstrated its high energy consumption. Renovation of the thermal insulation of the building was simulated, including all partitions enclosing rooms with regulated temperature, independent from the outdoor environment, and other unheated rooms. The effect of the thermal insulation renovation on the Primary Energy Factor and the Air Pollutant Emission Factor was tested. It was proven that the analyzed refurbishment of thermal insulation was insufficient to fulfill the reference value of primary non-renewable energy input, which would ensure considerable savings on costs (amounts of fuels) of heating

Health and safety in construction undertakings as exemplified by the Warmian-Masurian Voivodeship

Budownictwo jest sektorem gospodarki najbardziej narażonym na wypadki przy pracy. Główną ich przyczyną jest nieznajomość lub niestosowanie się do zasad bezpieczeństwa i higieny pracy, brak nadzoru nad pracownikami, niezapewnienie im odpowiednich do wykonywanej pracy środków ochrony indywidualnej oraz zwykłe niedbalstwo.Construction is a sector of economy which is the most exposed to accidents at work. The main cause of accidents is ignorance of Health and Safety regulations, failure to observe these regulations, lack of supervision of workers, lack of personal protection equipment for workers as well as sheer negligence