Modular Microstructured Reactors for Pilot‐ and Production Scale Chemistry

In recent years, two strategies in continuous‐flow plant technology attracted strengthened interest: First, the use of microstructured devices as a new tool for process intensification and second, the modularity of interchangeable devices which leads to more flexibility. To take advantage of both, these approaches were combined within the EU‐project CoPIRIDE. Microstructured modular reactors were fabricated by novel manufacturing techniques. Different types of such reactors were characterized in terms of reaction engineering. Residence time distribution, heat transfer performance, pressure drop, and liquid‐liquid mixing performance were investigated.     

A Specific Activity‐Based Probe to Monitor Family GH59 Galactosylceramidase,the Enzyme Deficient in Krabbe Disease

Galactosylceramidase (GALC) is the lysosomal β‐galactosidase responsible for the hydrolysis of galactosylceramide. Inherited deficiency in GALC causes Krabbe disease, a devastating neurological disorder characterized by accumulation of galactosylceramide and its deacylated counterpart, the toxic sphingoid base galactosylsphingosine (psychosine). We report the design and application of a fluorescently tagged activity‐based probe (ABP) for the sensitive and specific labeling of active GALC molecules from various species. The probe consists of a β‐galactopyranose‐configured cyclophellitol‐epoxide core, conferring specificity for GALC, equipped with a BODIPY fluorophore at C6 that allows visualization of active enzyme in cells and tissues. Detection of residual GALC in patient fibroblasts holds great promise for laboratory diagnosis of Krabbe disease. We further describe a procedure for in situ imaging of active GALC in murine brain by intra‐cerebroventricular infusion of the ABP. In conclusion, this GALC‐specific ABP should find broad applications in diagnosis, drug development, and evaluation of therapy for Krabbe disease.     

Diurnal Profiles of Melatonin Synthesis-Related Indoles,Catecholamines and Their Metabolites in the Duck Pineal Organ

This study characterizes the diurnal profiles of ten melatonin synthesis-related indoles, the quantitative relations between these compounds, and daily variations in the contents of catecholamines and their metabolites in the domestic duck pineal organ. Fourteen-week-old birds, which were reared under a 12L:12D cycle, were killed at two-hour intervals. The indole contents were measured using HPLC with fluorescence detection, whereas the levels of catecholamines and their metabolites were measured using HPLC with electrochemical detection. All indole contents, except for tryptophan, showed significant diurnal variations. The 5-hydroxytryptophan level was approximately two-fold higher during the scotophase than during the photophase. The serotonin content increased during the first half of the photophase, remained elevated for approximately 10 h and then rapidly decreased in the middle of the scotophase. N-acetylserotonin showed the most prominent changes, with a more than 15-fold increase at night. The melatonin cycle demonstrated only an approximately 5-fold difference between the peak and nadir. The 5-methoxytryptamine content was markedly elevated during the scotophase. The 5-hydroxyindole acetic acid, 5-hydroxytryptophol, 5-methoxyindole acetic acid and 5-methoxytryptophol profiles were analogous to the serotonin rhythm. The norepinephrine and dopamine contents showed no significant changes. The DOPA, DOPAC and homovanillic acid levels were higher during the scotophase than during the photophase. Vanillylmandelic acid showed the opposite rhythm, with an elevated level during the daytime.     

Consequences of Protonation of Diamines in the Gas Phase and the Solid State

An interesting model class of compounds are proton sponges—aromatic diamines characterized by exceptional basicity, such as 1,8-bis(dimethylamino)naphthalene (DMAN). For these compounds, protonation causes substantial redistribution of electron density which may be traced by observing the changes of structural parameters as well as of the properties of electron density at bond critical points. On protonation, electron density in DMAN goes from the terminal atoms towards the center of the molecule. This redistribution can also be confirmed by good quality neutron structural data. An ionic complex of DMAN with triformylmethane (TFM) acid has been studied by X-ray diffraction. We propose a multicenter model of hydrogen bonding {[Me₂N–H^0.5….^0.5H–NMe₂]⁺… X⁻} in this complex. The influence of weak intermolecular interactions of the DMANH⁺ cation with the nearest electronegative atom from the counterion on the strong intramolecular [N–H···N]⁺ hydrogen bonding has been demonstrated. Such interactions affect the localization of the proton in the intramolecular [N–H···N]⁺ hydrogen bridge.     

Synthesis and adsorption properties of nanocrystalline ferrites for kinetic modeling development

Nanocrystalline ferrites are known to be used in different applications, including industrial wastewater management. For environmental water issues, one of the most widely applied techniques is the adsorption of pollutants. The adsorption capacity of Congo red (CR) dye on different MFe₂O₄ (M = Co²⁺, Mg²⁺, Mn²⁺, Ni²⁺, and Zn²⁺) ferrites, synthesized by coprecipitation method, was determined. Specific isotherms and kinetic models were used to characterize the adsorption process. Interesting results were obtained for MgFe₂O₄ with adsorption capacity ranging from 39% up to 70% dependent on the initial dye concentration. Furthermore, an artificial intelligence model based on neural network was developed in order to model the adsorption rates followed by the generation of 3D adsorption rate models for each type of synthesized ferrite. These models were obtained in order to provide information about the particle-dye system`s kinetics at various initial CR concentration. Specific techniques were used to characterize the functionalized magnetic particles.     

Experimental assessment of heat storage properties and heat transfer characteristics of a phase change material slurry for air conditioning applications

A new microencapsulated phase change material slurry based on microencapsulated Rubitherm RT6 at high concentration (45% w/w) was tested. Some heat storage properties and heat transfer characteristics have been experimentally investigated in order to assess its suitability for the integration into a low temperature heat storage system for solar air conditioning applications. DSC tests were conducted to evaluate the cold storage capacity and phase change temperature range. A phase change interval of approximately 3 °C and a hysteresis behaviour of the enthalpy were identified. An experimental set-up was built in order to quantify the natural convection heat transfer occurring from a vertical helically coiled tube immersed in the phase change material slurry. First, tests were carried out using water in order to obtain natural convection heat transfer correlations. Then a comparison was conducted with the results obtained for the phase change material slurry. It was found that the values of the heat transfer coefficient for the phase change material slurry were higher than for water, under identical temperature conditions inside the phase change interval.     

Diffraction-Based Strategy for Monitoring Topographical Features Fabricated by Direct Laser Interference Patterning

Process monitoring in laser-based manufacturing has become a forward-looking strategy for industrial-scale laser machines to increase process reliability, efficiency, and economic profit. Moreover, monitoring techniques are successfully used in laser surface texturing workstations to improve and guarantee the quality of the produced workpieces by analyzing the resulting surface topography. Herein, dot-like periodic surface structures are fabricated on stainless steel samples by direct laser interference patterning (DLIP) using a 70 ps-pulsed laser system at an operating wavelength of 532 nm. A scatterometry-based measurement device is utilized to indirectly determine the mean depth and spatial period of the produced topography by analyzing the recorded diffraction patterns. As a result, the average depth and the spatial period of the dot-like structures can be estimated with a relative error below 15% and 2%, respectively. This new process monitoring approach enables a significant improvement in quality assurance in DLIP processing.