The qualitative spray analysis of liquid fuel in high-pressure piezoelectric injection system

The paper presents the methodology and tests results of the influence of the fuel injection pressure and combustion chamber back pressure on the changes of the fuel spray geometrical parameters injection uniformity and its quality during the injection. While evaluating the geometrical fuel spray parameters the spray penetration, speed of propagation were taken into account and while evaluating the quality of the fuel atomization the outflow of the fuel from the injector were considered. The tests reported here were performed for one value of the air back pressure at the various injection pressures. The fuel doses were changed by modifying the duration of the injection. A significant influence of theses parameters on the values of the operating indexes of the injection and atomization processes has been noted.

Piezo-assisted nuclear transfer affects cloning efficiency and may cause apoptosis

Even though it generates healthy adults, nuclear transfer in mammals remains an inefficient process. Mainly attributed to abnormal reprograming of the donor chromatin, this inefficiency may also be caused at least partly by a specific effect of the cloning technique which has not yet been well investigated. There are two main procedures for transferring nuclei into enucleated oocytes: fusion and piezoelectric microinjection, the latter being used mostly in mice. We have, therefore, decided to compare the quality and the developmental ability, bothin vivoandin vitro, of embryos reconstructed with electrofusion or piezoelectric injection. In addition, the effect of piezo setups of differing electric strengths was investigated. Along with the record of the rate of development, we compared the nuclear integrity in the blastomeres during the first cleavages as well as the morphological and cellular quality of the blastocysts. Our results show that the piezo-assisted micromanipulation can induce DNA damage in the reconstructed embryos, apoptosis, and reduced cell numbers in blastocysts as well as a lower rate of development to term. Even if piezo-driven injection facilitates a faster and more efficient rate of reconstruction, it should be used with precaution and with as low parameters as possible.