Comparison of dydrogesterone plus progesterone gel with subcutaneous aqueous progesterone plus progesterone gel for luteal phase supplementation of subsequent in vitro cycle in women after previous cycle failure

Objectives: The luteal phase supplementation (LPS) of the in vitro fertilization (IVF) cycle is crucial to increase the chance of a live birth. There is no preferred progestogen for use in the general population. The optimal progestogen regimen in the event of prior IVF failure is unknown. The aim was to compare the live birth rate for dydrogesterone plus progesterone gel versus aqueous progesterone plus progesterone gel in LPS of the IVF cycle in women with at least one previous IVF failure. Material and methods: A prospective randomized single-center study enrolled women with at least one previous IVF failure undergoing another IVF cycle. Women were randomly assigned in a 1:1 ratio to 2 arms depending on LPS protocol: dydrogesterone (Duphaston®) + progesterone in vaginal gel (Crinone®) vs aqueous progesterone solution in subcutaneous injection (Prolutex®) + progesterone in vaginal gel (Crinone®). All women underwent fresh embryo transfer. Results: The live birth rate with one prior IVF failure was 26.9% for D + PG vs 21.2% for AP + PG (p = 0.54), and with at least two IVF failures: 16% for D + PG vs 31.1% for AP + PG (p = 0.16). There were no significant differences in live birth rates between protocols, regardless of the number of prior IVF failures. Conclusions: In light of the evidence from this study that neither of the two LPS protocols is more effective in women with prior IVF failure, other factors, such as potential side effects, dosing convenience and patient preference, should be considered when choosing a treatment

Low Temperature Properties Of Fuel Mixtures Of Kerosene And Fame Type Used To Supply Turbine Engines In Marine And Other Non-Aeronautical Applications

A worldwide trend to popularise gradually increasing use of biofuels in various applications was a motivation for gaining interest in FAME as a commonly available biocomponent to fuels combusted in turbine engines. These engines are mainly used in aeronautics, but many of them are also used in other, non-aeronautical areas, including marine navigation. Specific conditions in which fuels are combusted in turbine engines used in these applications are the reason why fuel mixtures of kerosene and FAME type should reveal relevant low temperature characteristics. The article presents results of tests of low temperature properties of mixtures of the jet fuel Jet A-1 and methyl esters of higher fatty acids (FAME). The prepared mixtures contained different contents of FAME. The obtained results present changes of: viscosity, cloud point, pour point, crystallising point, and cold filter plugging point, depending on the percentage by volume of FAME. They also prove that the course of changes of low temperature properties of these mixtures is affected by chemical structure of the biocomponent

Combustion and Emissions Characteristics of the Turbine Engine Fueled with HEFA Blends from Different Feedstocks

In the next decade, due to the desire for significant reduction in the carbon footprint left by the aviation sector and the development of a sustainable alternatives to petroleum, fuel from renewable sources will play an increasing role as a propellant for turbine aircraft engines. Currently, apart from five types of jet fuel containing synthesized hydrocarbons that are certified by the ASTM D7566 standard, there is yet another synthetic blending component that is at the stage of testing and certification. Hydroprocessed esters and fatty acids enable the production of a synthetic component for jet fuel from any form of native fat or oil. Used feedstock affects the final synthetic blending component composition and consequently the properties of the blend for jet fuel and, as a result, the operation of turbine engines. A specialized laboratory test rig with a miniature turbojet engine was used for research, which is an interesting alternative to complex and expensive tests with full scale turbine engines. The results of this study revealed the differences in the parameters of engine performance and emission characteristics between tested fuels with synthetic blending components and neat jet fuel. The synthetic blending component was obtained from two different feedstock. Noticeable changes were obtained for fuel consumption, CO and NOx emissions. With the addition of the hydroprocessed esters and fatty acids (HEFA) component, the fuel consumption and CO emissions decrease. The opposite trend was observed for NOx emission. The tests presented in this article are a continuation of the authors’ research area related to alternative fuels for aviation

Influence of synthetic fuel on nitrile rubbers used in aviation

This paper investigates the influence of alternative fuel on selected butadiene–acrylonitrile rubbers used as seals in engine and fuel supply systems of post-Soviet aircrafts. The conventional fuel Jet A-1, the synthetic blending component from hydrotreated esters and fatty acids (HEFA) and its blend were interacted with the sample nitrile rubbers. HEFA technology has been approved by ASTM D7655 for use in turbine aircraft engines. The effect was evaluated on the basis of changes in the nitrile rubbers volume, mass and hardness. It has been confirmed that the synthetic component containing no aromatic hydrocarbons has a different effect on nitrile rubber than the conventional fuel. When the nitrile rubbers were subjected to microscopic observations, the most frequently observed effect was washing out or dissolving of nitrile rubber surface fragments