Математичні основи визначення функціонального стану операторів складних технологічних об’єктів

Забезпечення високої надійності роботи оператора, а, відповідно, системи «людина – машина» (СЛМ), – є пріоритетним завданням для більшості сфер промисловості та сучасного виробництва. Тому важливим є розробка заходів по підвищенню кваліфікації операторів складних технологічних об’єктів (СТО), шляхом підбору математичного апарату для який б дав можливість підвищити надійність його діяльності в структурі СЛМ

The biological role of fetuin-B : inhibition of zona pellucida hardening and preservation of female fertility in mice

Fetuin-B is a hepatic plasma protein, well conserved in mammals. Fetuin-B associates with the extracellular matrix and was shown to surround the oocytes during development and maturation. A layer of extracellular matrix, the Zona pellucida (ZP), surrounds mammalian oocytes. Before fertilization sperm are able to penetrate the ZP. After fertilization proteases are released by the oocyte, leading to structural ZP modification and inhibition of further sperm binding. This process is called fertilization-triggered ZP hardening. The hardened ZP is thought to be required to block polyspermy and to support embryonic development until blastocyst hatching and implantation into the uterus wall. Premature, fertilization-independent ZP hardening is known to occur spontaneous during in vitro cultivation (IVC), leading to decreased fertilization success at in vitro fertilization (IVF). It was shown that Fetub-/- females are infertile due to premature ZP hardening. Fetub+/- females only had half the serum level of fetuin-B, but were completely fertile. Infertility of Fetub-/- females was overcome by laser-assisted IVF and subsequent embryo transfer even into fetuin-B deficient foster mothers, showing that fetuin-B is critically required before fertilization, but is dispensable during later stages of embryonic and fetal live. Recombinant murine fetuin-B was shown to inhibit the proteolytic activity of ovastacin, the oocyte specific protease that triggers definitive ZP hardening. Accordingly, recombinant murine fetuin-B inhibited ZP hardening and increased IVF success without increasing polyspermy. In conclusion, fetuin-B inhibits spontaneously released ovastacin and thus premature ZP hardening either in vivo or in vitro, to maintain ZP permeability. After fertilization, the precipitous increase of ovastacin concentration triggered by degranulation, overwhelms the inhibition capacity of fetuin-B, resulting in fertilization-triggered ZP hardening. Fertilization-triggered ZP hardening proved less important in blocking polyspermy than thought previously. Fetuin-B deficiency either in vivo or in vitro lead to ZP hardening during oocyte maturation blocking fertilization. Thus fetuin-B represents a novel target for fertilization biology and reproductive medicine