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  • Author: P. Nawrocki x
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Open access

P. Nawrocki, A. Kochański and D. Myszka

Abstract

The article presents a statistical analysis of data collected from the observation of the production of austempered ductile iron. The impact assessment of the chemical composition, i.e. high contents of Cu and Ni on the properties of ductile iron isothermal tempered is critical to find the right chemical composition of austempered ductile iron. Based on the analyses range of the percentage of Cu and Ni which were selected in the cast iron to obtain material with high strength properties.

Open access

P. Lejba, J. Nawrocki, S. Schillak, D. Lemański, M. Lehmann and P. Nogaś

Time Transfer Realized by PPP Technique for Trimble Netrs and TTS-4 Receivers

This paper concerns determination of clock readings and position of two geodetic receivers: TRIMBLE NetRS and TTS-4, connected to the same antenna of Dorne Margolin choke ring type (IGS BOR1 point) with the usage of precise point positioning (PPP) technique. The TTS-4 receiver was constructed and provided with its software by the time and frequency team from Borowiec Astrogeodynamical Observatory (AOS). Parameters of the receiver clocks and antenna coordinates were determined for the period from 1 to 30 April 2011. The collected data in RINEX format include code and phase observations from GPS constellation recorded with 30 second interval. The computed positions of the antenna based on RINEX data files from TRIMBLE NetRS and TTS-4 receivers are practically the same. The differences of estimated coordinates are from 0.6 to 1.6 mm. However, the accuracy of the clock parameters computed for TRIMBLE NetRS receiver are by one order lower than for TTS-4. It means that TRIMBLE NetRS receiver synchronized with internal quartz oscillator can not be used for timing applications. Currently the AOS laboratory works on the realization and development of the PPP method are in progress. Ultimately, the method will allow very precise comparison of atomic clocks and atomic time scales over great distances based on GNSS phase measurements. This method will increase the quality of comparisons of the atomic time scales carried out in the world, as well as, significantly strengthen the quality of the Polish Atomic Time Scale - TA (PL).

Open access

K. Łukasik, P. Nawrocki, J. Misiak and D. Myszka

Abstract

The paper attempts to analyze distortions of cast iron and cast steel rings, after heat treatment cycles. The factors influencing distortion are: chemical composition of material, sample geometry, manufacturing process, hardenability, temperature and heat treatment method. Standard distortion tests are performed on C-ring samples. We selected a ring-model, which approximate the actual part, so that findings apply to gear rings. Because distortion depends on so many variables, this study followed strictly defined procedures. The research was started by specifying the appropriate geometry of the samples. Then, the heat treatment was conducted and samples were measured again. The obtained results allow to determine the value of the resulting distortion and their admissibility. The research will be used to evaluate the possibility of using the material to produce parts of equipment operated under extreme load conditions.

Open access

Mariusz J. Nawrocki, Piotr Celichowski, Joanna Budna, Artur Bryja, Wiesława Kranc, Sylwia Ciesiółka, Sylwia Borys, Sandra Knap, Michal Jeseta, Ronza Khozmi, Dorota Bukowska, Paweł Antosik, Klaus P. Brüssow, Małgorzata Bruska, Michał Nowicki, Maciej Zabel and Bartosz Kempisty

Abstract

The mammalian oocytes undergo significant biochemical and structural modifications during maturation both in vitro and in vivo. These changes involve chromatin reorganization and modification within metabolic status of cytoplasmic organelles. After oocytes’ successful maturation the substantially increased storage of RNA was observed. Moreover, the early embryo interaction with maternal endometrial tissue after fertilization is up to now considered as the main marker of proper embryo implantation and early growth. In this study, we first investigated the expression profile of genes involved in blood vessel formation and blood circulation in porcine oocytes before and after in vitro maturation.

The cumulus-oocyte complexes were collected from pubertal Landrace gilts and classified as before in vitro maturation (in Vivo) or after in vitro maturation (in Vitro). The RNA was isolated from these two experimental groups and analyzed using Affymetrix microarrays.

We found an increased expression of genes involved in ontological groups such as “blood circulation” (TPM1, ECE1, ACTA2, EPHX2, EDNRA, NPR2, MYOF, TACR3, VEGFA, GUCY1B3), “blood vessel development” (ANGPTL4, CYR61, SEMA5A, ID1, RHOB, RTN4, IHH, ANGPT2, EDNRA, TGFBR3, MYO1E, MMP14), and “blood vessels morphogenesis” (ANGPT2, as well as other common transcripts) in in Vivo group as compared to decreased expression of these genes in in Vitro group of oocytes.

It has been suggested that investigated genes undergo significant expression before in vitro maturation, when enhanced storage of large amount of RNA takes place. Creating templates for synthesis of proteins is required for formation of fully mature gametes and early embryo growth. Therefore we hypothesized that the processes of vascularization and/or angiogenesis reach a high activity in immature oocytes and are distinct from achievement of maturational stage by oocytes in pigs.

Open access

Mariusz J. Nawrocki, Joanna Budna, Piotr Celichowski, Ronza Khozmi, Artur Bryja, Wiesława Kranc, Sylwia Borys, Sylwia Ciesiółka, Sandra Knap, Michal Jeseta, Dorota Bukowska, Paweł Antosik, Klaus P. Brüssow, Małgorzata Bruska, Michał Nowicki, Maciej Zabel and Bartosz Kempisty

Abstract

The morphological and biochemical modification of oviductal epithelial cells (OECs) belongs to the compound process responsible for proper oocytes transport and successful fertilization. However, the main mechanisms which regulated this process are still not entirely known. Moreover, the OECs metabolism, which may be identified as the “cellular activity” marker, is poorly recognized. In this study we investigated the fructose and mannose metabolic pathway in porcine OECs primary long-term cultured in vitro.

In our study, we employ a primary long term in vitro culture (IVC) and microarray approach (the Affymetrix microarray were used for analysis of transcriptomic profile of OECs) for expression levels analysis.

We found that from the whole analyzed transcriptome, 1537 genes were upregulated and 995 were down regulated after 7 days of culture, 1471 genes were upregulated and 1061 were downregulated after 15 days of culture and 1329 genes were upregulated and 1203 were downregulated after 30 days of culture. Moreover, the differential expression of SORD, FPGT, PFKFB4, TPI1, MPI, ALDOC, HK2 and PFKFB3 at 24 hours, 7 day, 15 day and 30 day, was also observed.

We suggested that fructose and mannose metabolism may be important molecular bio-marker of porcine OECs capability in in vitro model. The metabolic profile is significantly accompanied by cells proliferation in vitro. The transcriptomic profile of SORD, FPGT, PFKFB4, TPI1, MPI, ALDOC, HK2 and PFKFB3 expression may be identified as “fingerprint” of fructose and mannose metabolism in OECs as well as involved in cellular in vitro developmental capacity in pigs.