Exchange Speed of Four-Component Nanorotors Correlates with Hammett Substituent Constants

Three distinct four-component supramolecular nanorotors were prepared, using, for the first time, bipyridine instead of phenanthroline stations in the stator. Following our established self-sorting protocol to multicomponent nanodevices, the nanorotors were self-assembled by mixing the stator, rotators with various pyridine head groups, copper(I) ions and 1,4-diazabicyclo[2.2.2]octane (DABCO). Whereas the exchange of a phenanthroline vs. a bipyridine station did not entail significant changes in the rotational exchange frequency, the para-substituents at the pyridine head group of the rotator had drastic consequences on the speed: 4-OMe (k298 = 35 kHz), 4-H (k298 = 77 kHz) and 4-NO2 (k298 = 843 kHz). The exchange frequency (log k) showed an excellent linear correlation with both the Hammett substituent constants and log K of the copper(I)–ligand interaction, proving that rotator–copper(I) bond cleavage is the key determining factor in the rate-determining step.

Microfluidic perfusion modulates growth and motor neuron differentiation of stem cell aggregates

This work explores how media exchange frequency and device geometry modulate the biochemical environment and impact three-dimensional stem cell differentiation.

FACTORS OF IMPLEMENTATION AND IMPORTANCE IN THE PROCESS OF KNOWLEDGE EXCHANGE IN THE CONSERVATIVE ANIMALS NETWORK OF BREEDERS AND INDUSTRY ORGANISATIONS. THE POLISH CASE

Knowledge is a key resource to support European agriculture in meeting today’s challenges such as global competition, food safety, human, animal and plant health as well as environmental protection requirements. The question arises as to which organisations in the current institutional system of agriculture provide knowledge to farmers who keep livestock of conservative breeds at the expected level of quality and exchange (frequency)? The aim of the research was to identify a new role of industry organisations in the transfer of knowledge and indicate variables determining the importance and exchange of farmers’ knowledge with industry organizations. The survey was conducted among 145 farmers in south-eastern Poland in 2017. The research instrument was a questionnaire of interviews with farms and representatives of industry organisations. Multiple regression analysis was used to demonstrate the influence of factors on the level of knowledge exchange (importance and frequency). The results of the research indicate that industry organisations can address their knowledge mainly to farms with poor financial stability (e.g. without a sales contract) and that the planned succession on the farm motivates the farmer to seek knowledge. Among the group of factors indifferent to the validity and implementation of knowledge exchange are: 1st the occurrence of a successor on the farm, 2nd the contracting of sales, 3rd the size of the farm and the 4th the age of the owner. It is recommended to create specialized industry compounds in Poland for conservative animal breeds (not only within species).