Live imaging of ERK signaling dynamics in differentiating mouse embryonic stem cells

Stimulation of the ERK/MAPK pathway is required for the exit from pluripotency and onset of differentiation in mouse embryonic stem cells (ESCs). The dynamic behavior of ERK activity in individual cells during this transition is unclear. Using a FRET-based biosensor, we monitored ERK signaling dynamics of single mouse ESCs during differentiation. ERK activity was highly heterogeneous, with considerable variability in ERK signaling between single cells within ESC colonies. Different triggers of differentiation induced distinct ERK activity profiles. Surprisingly, the dynamic features of ERK signaling were not strongly coupled to loss of pluripotency marker expression, regardless of the differentiation stimulus, suggesting the normal dynamic range of ERK signaling is not rate-limiting in single cells during differentiation. ERK signaling dynamics were sensitive to the degree of cell crowding and were similar in neighbouring cells. Sister cells from a mitotic division also showed more similar ERK activity, an effect that was apparent whether cells remained adjacent or moved apart after division. These data suggest a combination of cell lineage and niche contributes to the absolute level of ERK signaling in mouse ESCs

Intergranular properties and structural fractal analysis of batio3-ceramics doped by rare earth additives

Ferroelectric BaTiO3 as one of the most important ceramics materials in electronic, used on wide range of applications, can be modified with various dopant ions. In this paper, the influence of Er2O3, Yb2O3, Ho2O3 and La2O3, on microstructure, microelectronic and dielectric properties of BaTiO3-ceramics has been investigated. The solid solubility of rare-earth ions in the BaTiO3 perovskite structure has been studied by different methods of structural analysis including SEM-JEOL 5300 and energy dispersive spectrometer (EDS) system. BaTiO3-ceramics doped with 0.01 up to 1 wt% of rare-earth additives were prepared by conventional solid state procedure and sintered from 1320 degrees C to 1380 degrees C for four hours. We also applied the fractal method in microstructure analysis of sintered ceramics, especially as influence on intergranular capacitor and dielectric peoperties of BaTiO3-ceramics. This fractal nature effect has been used for better understanding integrated microelectronics characteristics and circuits

Fluorescence lifetime imaging using a single photon avalanche diode array sensor

Single photon detectors allows us work with the weakest fluorescence signals. Single photon arrays, combined with ps-controlled gating allow us to create image maps of fluorescence lifetimes, which can be used for in-vivo discrimination of tissue activity. Here we present fluorescence lifetime imaging using the ‘SwissSPAD’ sensor, a 512-by-128-pixel array of gated single photon detectors, fabricated in a standard high-voltage 0.35 μm CMOS process. We present a protocol for spatially resolved lifetime measurements where the lifetime can be retrieved for each pixel. We demonstrate the system by imaging patterns of Fluorescein and Rhodamine B on test slides, as well as measuring mixed samples to retrieve both components of the decay lifetime. The single photon sensitivity of the sensor creates a valuable instrument to perform live cell or live animal (in vivo) measurements of the weak autofluorescent signals, for example distinguishing unlabelled free and bound NADH. Our ultimate goal is to create a real time fluorescence lifetime imaging system, possibly integrated into augmented reality goggles, which could allow immediate discrimination of in vivo tissues

Warfare tourism: an opportunity for Croatia?

This article explores only a variation of tourism – warfare tourism – in Croatia, which is a recognised tourist destination. The main objective of this multidisciplinary research is to clarify and classify young residents (undergraduate students) of Croatia into different clusters based on their views of the potential for warfare tourism development in the country. A total of 292 completed questionnaires were recorded and prepared for empirical analyses. Ward’s principal component score method, independent sample test and descriptive analysis were employed in this study. We found that two clusters of youths could be identified – believers and doubters, the latter representing the majority. The difference between clusters, in fact, is not so big: however, believers, contrary to doubters, do recognise warfare tourism opportunities for the development of war-affected areas in Croatia, opportunities that first need to be conceptualised on the strategic level (country/county/city/municipality)