Warsaw University of Technology

About: Warsaw University of Technology is a education organization based out in Warsaw, Poland. It is known for research contribution in the topics: Microstructure & Optical fiber. The organization has 14293 authors who have published 34362 publications receiving 492211 citations. The organization is also known as: Warsaw Polytechnic & Politechnika Warszawska.

Multiplicity distribution and spectra of negatively charged hadrons in Au + Au collisions at √SNN = 130 GeV

Abstract: The minimum-bias multiplicity distribution and the transverse momentum and pseudorapidity distributions for central collisions have been measured for negative hadrons (h{sup -}) in Au+Au interactions at s{sub NN}=130 GeV . The multiplicity density at midrapidity for the 5% most central interactions is dN{sub h{sup -}}/d{eta}|{sub {eta}=0} =280{+-}1(stat){+-}20(syst) , an increase per participant of 38% relative to p{bar p} collisions at the same energy. The mean transverse momentum is 0.508{+-}0.012 GeV/c and is larger than in central Pb+Pb collisions at lower energies. The scaling of the h{sup -} yield per participant is a strong function of p{sub {perpendicular}} . The pseudorapidity distribution is almost constant within |{eta}|<1 .

Mechanosynthesis of the hybrid perovskite CH3NH3PbI3: characterization and the corresponding solar cell efficiency

Abstract: We present a facile mechanochemical route for the preparation of hybrid CH3NH3PbI3 (MAPbI3) perovskite particles with the size of several hundred nanometers for high-efficiency thin-film photovoltaic devices. Powder X-ray diffraction measurements demonstrate that mechanosynthesis is a suitable strategy to produce a highly crystalline CH3NH3PbI3 material showing no detectable amounts of the starting CH3NH3I and PbI2 reagents. Thermal stability measurements based on the thermogravimetric analysis data of mechanosynthesized perovskite particles indicated that the as-ground MAPbI3 is stable up to 300 °C with no detectable material loss at lower temperatures. The optical properties of newly synthesized perovskite particles were characterized by applying steady state absorption and fluorescence spectroscopy, which confirmed a direct band-gap of 1.48 eV. Time resolved single photon counting measurements revealed that 70% of charges undergo recombination with a 61 ns lifetime. The solar cell devices made from mechanosynthesized perovskite particles achieved a power conversion efficiency of 9.1% when applying a one step deposition method.

A microfluidic-based platform for tumour spheroid culture, monitoring and drug screening.

Abstract: The development of novel cellular models that can replace animals in preclinical trials of drug candidates is one of the major goals of cell engineering. Current in vitro screening methods hardly correspond with the in vivo situation, whereas there is a lack of assays for more accurate cell culture models. Therefore, development of automated assays for 3D cell culture models is urgently required. In this work, we present a SpheroChip system: a microfluidic-based platform for long-term 3D cell culture and analysis. The system is compatible with commercially available microplate readers and provides continuous, in situ monitoring of tumour spheroids cultured on a chip. The microfluidic chip consists of cell culture microchambers and hemispherical microwells connected with a concentration gradient generator. HT-29 and Hep-G2 cells were successfully cultured as tumour spheroids in the SpheroChip, and metabolic activity of cells was monitored for up to two weeks by in situ fluorimetric measurements. Cellular response to an anticancer drug was observed using the SpheroChip. The experimental setup provided the unique possibility of observing dynamic changes in metabolic activity of one culture during sequencing days after drug dosage. According to this new approach, unknown phenomena of cellular response to the anticancer drug were observed, such as increase of metabolic activity shortly after drug dosage. Moreover, the influence of a second dose of a drug was evaluated. The SpheroChip system can be used by researchers working on drug screening, evaluation of anticancer procedures and chemoresistance phenomena.