BackgroundLivestock-associated Staphylococcus aureus (LA-SA) draws increasing attention due to its particular ability to colonize farm animals and be transmitted to people, which in turn leads to its spread in the environment. The aim of the study was to determine the dissemination of LA-SA on pig farms selected throughout Poland, characterize the population structure of identified S. aureus, and assess the prevalence of LA-SA carriage amongst farmers and veterinarians being in contact with pigs.Methods and findingsThe study was conducted on 123 pig farms (89 farrow-to-finish and 34 nucleus herds), located in 15 out of 16 provinces of Poland. Human and pig nasal swabs, as well as dust samples were analyzed. S. aureus was detected on 79 (64.2%) farms from 14 provinces. Amongst these farms LA-SA-positive farms dominated (71/79, 89.9%, 95% CI [81.0%, 95.5%]). The prevalence of LA-MRSA-positive farms was lower than LA-MSSA-positive (36.6% of LA-SA-positive farms, 95% CI [25.5%, 48.9%] vs. 74.6%, 95% CI [62.9%, 84.2%]). In total, 190 S. aureus isolates were identified: 72 (38%) MRSA and 118 (62%) methicillin-susceptible S. aureus (MSSA), of which 174 (92%) isolates were classified to three livestock-associated lineages: CC398 (73%), CC9 (13%), and CC30/ST433 (6%). All CC398 isolates belonged to the animal clade. Four LA-MRSA clones were detected: ST433-IVa(2B) clone (n = 8, 11%), described to the best of our knowledge for the first time, and three ST398 clones (n = 64, 89%) with the most prevalent being ST398-V(5C2&5)c, followed by ST398-V(5C2), and ST398-IVa(2B).Nasal carriage of LA-SA by pig farmers was estimated at 13.2% (38/283), CC398 carriage at 12.7% (36/283) and ST398-MRSA carriage at 3.2% (9/283), whereas by veterinarians at 21.1% (8/38), 18.4% (7/38) and 10.5% (4/38), respectively.ConclusionsThe prevalence of LA-MRSA-positive pig farms in Poland has increased considerably since 2008, when the first MRSA EU baseline survey was conducted in Europe. On Polish pig farms CC398 of the animal clade predominates, this being also reflected in the prevalence of CC398 nasal carriage in farmers and veterinarians. However, finding a new ST433-IVa(2B) clone provides evidence for the continuing evolution of LA-MRSA and argues for further monitoring of S. aureus in farm animals.

Presented paper is focused on the performance analysis of turbofan engine with additional combustion chamber fueled by alternative fuel. Additional combustion chamber was situated between high pressure turbine and low pressure turbine. Such configuration is also know under the name inter turbine burner (ITB). As an alternative fuels burn in additional combustion chamber were selected cryogenics fuels: liquid hydrogen and liquid methane. The main combustion chamber was supplied by conventional aviation fuel - kerosene. Thermodynamic model of turbofan engine with ITB was implemented in MATLAB environment. The problem of modeling an additional combustion chamber was presented.Analysis was carried out for take-off conditions. Obtained results indicate that implementation of ITB exert a positive influence on engine performance result in thrust increase.

The article presents a numerical CFD simulation of a throttle-check valve used in an innovative control system for two pneumatic drives. This type of control is used in an innovative rehabilitation device for lower limbs. In order to determine the boundary conditions, experimental tests were carried out. The throttle valves on the test stand were scaled and the air flow rate values were read for different valve opening heights. The purpose of this article is to present a CFD simulation of a pre-adjusted check valve throttle. Numerical simulation (CFD) makes it possible to study the flow phenomena inside a pneumatic throttle-check valve, with different sizes of flow gaps. The obtained results made it possible to determine the distribution of physical quantities of static pressure, the velocity of the medium flowing through the valve, or the vector velocity distribution. The throttle valve assembly has been scaled for a suitable degree of synchronization of the movement of the piston actuators independently of the different external loads acting on each of them. The authors investigated airflow phenomena for different valve opening heights. The simulation provided information on the occurrence of supersonic and subsonic flow velocities at specific valve opening heights.

Presented paper is focused on the influence of additional combustor chamber named inter turbine burner on turbofan engine unit parameters. Investigation has been made how changing selected engine parameters affect its performance. A comparison has been made between the baseline turbofan engine and the engine with ITB. Engine thermodynamics model was prepared in MATLAB software. Main combustion chamber was fueled by kerosene, commmonly used in aviation transport, while inter turbine burner by alternative fuel. As an alternative fuel were choose liquid hydrogen and methane. Numerical researches were carried out for take-off conditions. Engine specific thrust and specific fuel consumption were obtained as a function of bypass ratio, turbine inlet temperature, fan pressure ratio, HPC and LPC pressure ratio. The results of the study indicate that hybrid engine with additional combustion chamber fueled by hydrogen fuel is more efficient than other studied cases.