Photoinduced properties of "T-type" polyimides with azobenzene or azopyridine moieties

In this work series of “T-type” polyimides with azobenzene or azopyridine moieties were investigated. It is the first report where the “T-type” polyimides with derivatives of azopyridine were investigated. The cis-trans isomerization in the dark in the solid-state was showed. Polyimides with azobenzene derivatives exhibited higher stability of cis-trans recovery than their azobenzene analogues. For the inscription of the surface relief gratings, two different intensities of light (10 and 45 mJ/cm2) and a number of pulses (10 and 100) were used. Polyimides showed the modulation of SRGs up to almost 330 nm. Our studies showed, that azopolyimides are able to orient the nematic liquid crystal molecules in cell-based on effect at the twisted nematic. The obtained maximum value of tON was 0.9 ms (1 kHz, 1.5 V/μm) for polyimide with azobenzene moieties. Azopolyimides may be successfully used in many photonic devices based on the alignment of the liquid crystal mixture i.e. LC diffraction gratings, Fresnel lens, Vortex, in a photo-pattering technology for creating radical and azimuthal orienting layers

AI COMPONENTS FOR PERFORMANCE MEASUREMENT - A BIBLIOMETRIC APPROACH

This study employs a bibliometric approach to analyze the landscape of artificial intelligence (AI) components used in performance measurement. As organizations increasingly leverage AI for optimizing processes and decisionmaking, understanding the trends in AI components becomes imperative. The identified AI components are classified based on their roles in enhancing performance measurement, offering insights into the prevalent methodologies and emerging technologies. The bibliometric analysis encompasses a comprehensive review of scholarly articles, conference papers, and patents, systematically exploring the evolving field. In this research, the methodology involves data extraction from reputable academic databases and patent repositories, followed by applying bibliometric techniques to quantify and visualize key aspects. The findings of this study contribute to the existing knowledge by mapping the intellectual structure of AI components for performance measurement

Quick Procedure to Evaluate the Oxygen Mass Transfer Resistance in Aerated Laboratory-scale Bioreactors

Oxygen transfer intensity is a major concern whenever conducting enzymatic reactions or bioprocesses, which require air for microbial growth or enzymatic oxidative steps. Agitation in bio-reaction units is directly related to oxygen transport from the gas phase to liquid phase followed by the oxygen uptake by the individual microbial cell or oxygen consumption in enzymatic oxidation reactions. In fact, activity of microorganisms or of the enzyme (oxidase) is monitored by the use of oxygen from supplied air. A limitation in the supplied oxygen, due to mass transport resistance or a consumption rate faster than the transported oxygen rate, may cause a decrease in the cell growing rate or a decrease of the overall enzymatic reaction rate. Consequently, a close control of the available oxygen in the liquid phase is implemented for any type of aerobic bioreactor, the amount of dissolved oxygen (DO) being continuously measured by means of DO-meters. As the solubility of oxygen in water is not very high (ca. 9 mg/L at 20 o C), its overall consumption rate is dependent on a large number of factors, the most important being the diffusion coefficient, temperature, gas-liquid mass transfer coefficient K L a , and the rate of microbial/enzymatic reactions. Oxygen transfer from gas phase to the reaction site (cells, enzyme) takes place in several steps. First, oxygen is transferred through the gas-liquid interface, then it is transported through bulk liquid and finally into the microbial cell. To improve the oxygenation rate, sophisticated mixing and air sparger systems are implemented on both laboratory and industrial scale bioreactors. Air under pressure is supplied through a tube end consisting in 'O' rings with very fine holes or orifices. The size of bubbles, which affects the mass transfer process, depends on the holes' size and type of sparger. For very fine and uniform bubbles with effective gas dispersion, a micro-sparger system is used instead of a sparger, consisting in highly porous ceramic material. Air dispersion in liquid phase is not only related to the sparger, but also on the type of impeller and mixing intensity. The appropriate position and type of the impeller can ensure the even distribution of the gas in the reactor. High agitation is favourable to the mixing, but a very high stirring speed may cause shear forces, damaging the cells and leading to a spotty aeration of the liquid. Special chapters are dedicated to mass transfer evaluation in the framework of bioreactor design and operation with various areas of applicability: industrial biosynthesis To optimise the aeration rate, knowing the gas-liquid mass transfer resistance is essential not only for a theoretical process analysis, but also for practical reasons related to bioprocess development. As the experimental observation can indicate only the overall oxygen uptake by the bioprocess, it is highly important to separate the contribution of the physical gas-liquid transport to its consumption in bio-reactions. Such analysis is possible only from separate determinations of the K L a coefficient and of the (bio)reaction rates. Experiments should be conducted in the absence of reaction, or under operating regimes at high aeration rates, making the whole process kinetically controllable. The volumetric mass transfer coefficient K L a is dependent on a large number of factors. This is why its precise evaluation is difficult due to its strong dependence on the liquid phase properties, mixing, gas solubility, operating conditions (temperature), sparger depth, aeration rate, vessel volume and geometry, baffles, liquid surface tension, etc

The Mio-Pliocene transition in the Dacian Basin (Eastern Paratethys): Paleomagnetism, mollusks, microfauna and sedimentary facies of the Pontian regional stage

Well-documented, high-resolution sedimentary sections are critical to our understanding of the often eventful evolution of semi-isolated basins that form during the final stages of continent–continent convergence, as exemplified by the Mediterranean-Paratethys system. Due to its nearly land-locked position in the Late Miocene, the Mediterranean experienced the renowned Messinian Salinity Crisis. At the same time, the equally restricted Eastern Paratethys to the north-east evolved in a potentially related, but very distinctive way. The events of this period are fully recorded in the sediments deposited during the Pontian regional stage in the Dacian Basin, part of the Eastern Paratethys, which we here investigate in detail in the best available section. The studied interval of the Slănicul de Buzău section is more than 2 km thick and almost continuously exposed. It is analyzed for paleomagnetism, mollusks, microfauna and sedimentary facies. This allows us to refine previous results from nearby but less complete sections, with particular improvements concerning resolution, biostratigraphy and sedimentology. The marine incursion just below the base of the Pontian (6.1 Ma) is shown to significantly predate the early Pontian highstand. The biostratigraphically defined onset of the middle Pontian (6.0 Ma) coincides with the highstand and slightly predates the major regression (5.9–5.6 Ma) for which the middle Pontian is best known. In the here-investigated section, the transgression at the beginning of the late Pontian (5.6 Ma) is followed by a regressive trend culminating between 5.4 and 5.2 Ma around the Mio-Pliocene boundary (5.33 Ma). The late Pontian sedimentation then becomes relatively stable and the fauna gradually transitions (4.8 Ma) into assemblages characteristic for the Dacian stage of the Dacian Basin, while overall significantly diverging from the rest of the Eastern Paratethys. Finally, we discuss several factors that could affect accuracy and applicability of the updated chronostratigraphy, warranting some caution

Paratethys pacing of the Messinian Salinity Crisis:Low salinity waters contributing to gypsum precipitation?

During the so-called Messinian Salinity Crisis (MSC: 5.97-5.33 Myr ago), reduced exchange with the Atlantic Ocean caused the Mediterranean to develop into a “saline giant” wherein ∼1 million km3 of evaporites (gypsum and halite) were deposited. Despite decades of research it is still poorly understood exactly how and where in the water column these evaporites formed. Gypsum formation commonly requires enhanced dry conditions (evaporation exceeding precipitation), but recent studies also suggested major freshwater inputs into the Mediterranean during MSC-gypsum formation. Here we use strontium isotope ratios of ostracods to show that low-saline water from the Paratethys Seas actually contributed to the precipitation of Mediterranean evaporites. This apparent paradox urges for an alternative mechanism underlying gypsum precipitation. We propose that Paratethys inflow would enhance stratification in the Mediterranean and result in a low-salinity surface-water layer with high Ca/Cl and SO4/Cl ratios. We show that evaporation of this surface water can become saturated in gypsum at a salinity of ∼40, in line with salinities reported from fluid inclusions in MSC evaporites

Are the metal identity and stoichiometry of metal complexes important for colchicine site binding and inhibition of tubulin polymerization?

Quite recently we discovered that copper(II) complexes with isomeric morpholine-thiosemicarbazone (morph-TSCs) hybrid ligands show good cytotoxicity in cancer cells and that the molecular target responsible for this activity might be..