Search

Purpose: Does IDEF mapping help monitor the technical process of IUI and explore the potential improvements which might contribute to increased pregnancy and live birth rates? Method: Retrospective analysis of 1729 homologous IUI cycles of couples attending a fertility clinic in a university hospital setting. Standardized conventional semen parameters were analyzed and the semen samples prepared via discontinuous density gradient centrifugation. Results: There was no significant association between sperm concentration, motility and morphology (analysis phase), and pregnancy outcome. Only female and male ages were significantly associated with the pregnancy outcome. There was a significant difference in the odds on clinical pregnancies and live births when analysis was ≤ 21 min initiated, and < 107 min between sample production and IUI, adjusted for male and female age. Conclusions: Adjusting for the couple's age, we could show that time intervals between semen production and analysis and IUI when kept low significantly influenced clinical pregnancies and live births. [ABSTRACT FROM AUTHOR]

A magnetic field and temperature was shown to affect disperse composition, electrophoretic behavior, and aggregation stability of synthesized magnetite particles. When synthesis proceeds, a process of the nucleation of ultramicroscopic Fe3O4 particles prevails over a process of their aggregation. Here an electrostatic factor of stability of magnetite suspension plays an important role. An application of the magnetic field decreases the aggregation stability and increases the sedimentation rate of product particles. [ABSTRACT FROM AUTHOR]

Molecular parameters for 136 compounds with disclike molecules and known phase diagrams were calculated and analyzed by a procedure proposed previously in order to improve the method for predicting possible types of mesomorphism from molecular characteristics. A correlation between the value of the molecular parameter Mm and the existence of a nematic liquid crystal is established. An analysis of calculated values of Mm for 27 new molecules of similar structure yielded compounds that are likely to form nematic liquid crystals. To verify the prediction, one of these compounds — 1,3,5 cyclohexanebenzoatebenzene — was synthesized and its phase diagram was studied. The prediction results agree with experimental data: the range of existence of a nematic mesophase was established (130.5–134.5°). Rapid cooling followed by prolonged storage of samples at room temperature without mechanical deformation led to vitrification of the samples ith preserved mesophase texture. Mechanical deformation of vitrified samples resulted in their transition to the crystal phase. [ABSTRACT FROM AUTHOR]

This paper reports on synthesis and investigation of columnar mesophases of the new members of the homologous series of nitro and amino derivatives of hexaalkoxytriphenylenes, whose mesomorphism was predicted earlier. The forecast is in good agreement with the experimental data. The effect of the introduction of the donor and acceptor groups into the central fragment of triphenylene on the phase transition temperature, texture, and range of existence of columnar mesophases is examined. The predicting ability of the molecular parameters suggested previously for the series under analysis is discussed. It is found that introduction of a nitro group, which is a strong electron acceptor, into the central fragment of triphenylene lowers the melting temperature of the compound versus its analog and does not promote columnar mesomorphism in the lower nonmesomorphous homologs. At the same time, this slightly expands the range of existence of the mesophase in higher homologs. [ABSTRACT FROM AUTHOR]