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Number of results: 48
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Abstract

The aim of the study was to develop new laparoscopic technique for repeated recovery of sheep oocytes. Oocytes were aspirated with specifically designed catheter. It allowed to recover oocytes without ovary damage and to preserve very good quality of recovered oocytes. Fifteen ewes were oocytes donors. Oocytes were collected: one time (group I, n=15), two times (group II, n=15), three times (group III, n=10), four times (group IV, n=5). The endoscope was inserted into the abdominal cavity. Two trockars for putting the manipulators were inserted 15 cm cranial from the udder. Oocytes were collected by aspiration of the follicular fluid from the ovarian follicles. The observed clinical complications were: ovary bleeding and cicatrix at place of needle insertion, the fragmentary adhesion of infundibulum and ovary, adhesions of omentum and peri- toneum near the place where the grasping forceps were inserted and adhesion of ovary and uterus. Ovarian follicles (n=204) were aspirated, 130 (63.8%) oocytes were obtained. Out of 130 obtained oocytes, 112 were qualified for in vitro maturation. The remaining 18 oocytes (13.8%) were rejected due to cytoplasmic changes. The proposed technique allows for the collecting oocytes of good quality that can be used for IMV/IVF techniques and cloning.
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Abstract

Suspended matter, phytoplankton and light attenuation were investigated in various North East Greenland, Svalbard and Siberian river mouths in 1992-1994. The amount of mineral suspensions well correlated with freshwater discharge in the case of tidal glacier bays, while such correlation in Siberian rivers and pack ice meltwater was not found. Freshwater phytoplankton species were found in Siberian estuaries only and in two other ecosystems marine and ice phytoplankton species prevailed. The light attenuation connected with freshwater discharge seems to be a key factor limiting primary production in coastal Actic waters in the summer. The amount of glacial suspensions well correlated with the salinity drop in the case of Svalbard, while Siberian river estuaries produced very turbid waters with the suspension loads not correlated to freshwater or depth.
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Abstract

The research aimed to use chemical, geochemical, and ecotoxicity indices to assess the heavy metals content in soils with different degrees of exposure to human pressure. The research was conducted in southern Poland, in the Malopolska (Little Poland) province. All metal contents exceeded geochemical background levels. The highest values of the Igeo index were found for cadmium and were 10.05 (grasslands), 9.31 (forest), and 5.54 (arable lands), indicating extreme soil pollution (class 6) with this metal. Mean integrated pollution index (IPI) values, depending on the kind of use, amounted to 3.4 for arable lands, 4.9 for forests, and 6.6 for grasslands. These values are indicative of a high level of soil pollution in arable lands and an extremely high level of soil pollution in grasslands and forests. Depending on the type of soil use, Vibrio fischeri luminescence inhibition was from -33 to 59% (arable lands), from -48 to 78% (grasslands), and from 0 to 88% (forest). Significantly the highest toxicity was found in soils collected from forest grounds.
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Abstract

In the case of mining machines, tribocorrosion damage is often observed. This type of consumption is caused by the joint action of mining environment factors such as abrasive and water. The search for methods to counteract tribocorrosion is of great practical importance, but it must be combined with the knowledge of methods of forecasting the value of wear. This paper presents a model of prediction of tribocorrosive wear adapted to corrodible materials – ADI containing Ni and Cu, with the strength class of 800 MPa – and results of a two-stage study on the tribocorrosive wear. Presented results indicate a distinct effect of synergy between friction and corrosion in the total wear of ADI. The tribocorrosion tests confimed the adequacy of the model developed for the ADI.
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