Development of Nd (III)-Based Terahertz Absorbers Revealing Temperature Dependent Near-Infrared Luminescence

Molecular vibrations in the solid-state, detectable in the terahertz (THz) region, are the subject of research to further develop THz technologies. To observe such vibrations in terahertz time-domain spectroscopy (THz-TDS) and low-frequency (LF) Raman spectroscopy, two supramolecular assemblies with the formula [Nd^III (phen)₃ (NCX)₃] 0.3EtOH (X = S, 1-S; Se, 1-Se) were designed and prepared. Both compounds show several THz-TDS and LF-Raman peaks in the sub-THz range, with the lowest frequencies of 0.65 and 0.59 THz for 1-S and 1-Se, and 0.75 and 0.61 THz for 1-S and 1-Se, respectively. The peak redshift was observed due to the substitution of SCN⁻ by SeCN⁻. Additionally, temperature-dependent TDS-THz studies showed a thermal blueshift phenomenon, as the peak position shifted to 0.68 THz for 1-S and 0.62 THz for 1-Se at 10 K. Based on ab initio calculations, sub-THz vibrations were ascribed to the swaying of the three thiocyanate/selenocyanate. Moreover, both samples exhibited near-infrared (NIR) emission from Nd (III), and very good thermometric properties in the 300–150 K range, comparable to neodymium (III) oxide-based thermometers and higher than previously reported complexes. Moreover, the temperature dependence of fluorescence and THz spectroscopy analysis showed that the reduction in anharmonic thermal vibrations leads to a significant increase in the intensity and a reduction in the width of the emission and LF absorption peaks. These studies provide the basis for developing new routes to adjust the LF vibrational absorption.     

Mitochondrial Dysfunction in Spinocerebellar Ataxia Type 3 Is Linked to VDAC1 Deubiquitination

Dysfunctional mitochondria are linked to several neurodegenerative diseases. Metabolic defects, a symptom which can result from dysfunctional mitochondria, are also present in spinocerebellar ataxia type 3 (SCA3), also known as Machado–Joseph disease, the most frequent, dominantly inherited neurodegenerative ataxia worldwide. Mitochondrial dysfunction has been reported for several neurodegenerative disorders and ataxin-3 is known to deubiquitinylate parkin, a key protein required for canonical mitophagy. In this study, we analyzed mitochondrial function and mitophagy in a patient-derived SCA3 cell model. Human fibroblast lines isolated from SCA3 patients were immortalized and characterized. SCA3 patient fibroblasts revealed circular, ring-shaped mitochondria and featured reduced OXPHOS complexes, ATP production and cell viability. We show that wildtype ataxin-3 deubiquitinates VDAC1 (voltage-dependent anion channel 1), a member of the mitochondrial permeability transition pore and a parkin substrate. In SCA3 patients, VDAC1 deubiquitination and parkin recruitment to the depolarized mitochondria is inhibited. Increased p62-linked mitophagy, autophagosome formation and autophagy is observed under disease conditions, which is in line with mitochondrial fission. SCA3 fibroblast lines demonstrated a mitochondrial phenotype and dysregulation of parkin-VDAC1-mediated mitophagy, thereby promoting mitochondrial quality control via alternative pathways.     

Artificial Maturation of the Highly Active Heterodimeric [FeFe] Hydrogenase from Desulfovibrio desulfuricans ATCC 7757

Hydrogenases catalyze the reduction of protons and oxidation of molecular hydrogen with high turnover frequencies and low overpotentials under ambient conditions. The heterodimeric [FeFe] hydrogenase from Desulfovibrio desulfuricans has an exceptionally high activity, and can be purified aerobically in an oxygen-stable inactive state. Recently, it was demonstrated that monomeric [FeFe] hydrogenases produced recombinantly in Escherichia coli can be artificially maturated by simply incubating the inactive “apo” enzymes with the synthetic [2Fe] cofactor mimic [Fe₂(adt)(CO)₄(CN)₂]²⁻. Here, we use the same technique to produce the heterodimeric “apo” hydrogenase from D. desulfuricans in E. coli with a high yield and purity, and maturate the “apo” enzyme with [Fe₂(adt)(CO)₄(CN)₂]²⁻ to generate fully active “holo” enzyme. Interestingly, the rate of the artificial maturation process with D. desulfuricans is significantly slower than that for all other hydrogenases tested so far. The artificially maturated enzyme is spectroscopically and electrochemically identical to the native enzyme and shows high rates of hydrogen production (3700 s⁻¹) and hydrogen oxidation (63,000 s⁻¹). We expect that our highly efficient production method will facilitate future studies of this enzyme and other related [FeFe] hydrogenases from Desulfovibrio species.     

Neue Konzepte der Reststoffverwertung in der Lebensmittelindustrie - Chancen für die Kartoffelstärkeindustrie

New concepts for the utilisation of residual products from food industry - Prospects for the potato starch industry. In disposed waste are quite a lot of reusable substances of high value. These residual products can be transferred into commercial products in dependency to the adequate technology either as raw material for secondary processes, as operating supplies or as ingredients of novel products. Numerous valuable substances in food production are suitable for separation and recycling at the end of their life cycle even though present separation and recycling processes are not absolutely cost saving. Based on a concept of food production in its entirely the actual state is exemplary demonstrated at the potato starch industry in its occurrence, quantity and utilisation of the residual products. The target state of a clean production process will be realised by the development of multifunctional food ingredients. The outlined concept can be naturally transferred to several areas of industrial food production. The intentions of this research area are located at the development of techniques, which fulfil the conditions of environmental protection with costs to a minimum.     

Synergy of combining sonolysis and photocatalysis in the degradation and mineralization of chlorinated aromatic compounds

Merits of using advanced oxidation processes such as sonolysis and photocatalysis as well as a combination of the two have been explored using model herbicides such as 2,4-dichlorophenoxy acetic acid and 2,4-dichlorophenoxypropionic acid and the chlorinated phenols 2,4-dichlorophenol and 2,4,6-trichlorophenol. Whereas sonolysis is quite effective in the initial degradation of chlorinated aromatic molecules, complete mineralization is difficult to achieve. Photocatalysis is selective toward the degradation of polar compounds but causes the build up of undesirable chemical intermediates. In contrast to sonolytic degradation, photocatalysis is very effective toward achieving complete mineralization. By simultaneously carrying out high-frequency sonolysis and photocatalysis we have succeeded in achieving faster and complete mineralization with no build up of toxic intermediates even at very low catalyst loadings. The synergy of combining the two advanced oxidation processes is discussed.     

Entwicklung eines optisch zugänglichen Reaktors zur Thermographiemessung in einer Katalysatorschüttung

To measure the microkinetics in heterogeneously catalyzed strongly exothermic gas phase reaction heat and mass transfer limitations should be excluded. Also an unequal distribution of temperature in the catalyst fixed bed, like a hot spot, distorts the results of microkinetic investigations. A promising approach to measure the temperature contactless is thermography. For this work, an optically accessible reactor is developed to measure the temperature in a catalytically powder fixed bed. In the scope of this work, this technique is used to investigate the temperature development and distribution during the exothermal CO₂ methanation depending on the bed and gas dilution and the reactor performance.     

Ultraschall-induzierte Synthese von Trlmethylsilylessigsäuresilylestern

Ultrasound-induced Synthesis of Trimethylsilylacetic Acid Trimethylsilylester . The reaction of bromoacetic acid trimethylsilylester with zinc in presence of chlorotrimethylsilane is promoted by sono-waves. The trimethylsilylacetic acid trimethylsilylester could be obtained in high yield. Different products are observed in presence of dichloro dimethylsilane. Mechanical aspects are discussed.     

Prediction of Functional Consequences of Missense Mutations in ANO4 Gene

The anoctamin (TMEM16) family of transmembrane protein consists of ten members in vertebrates, which act as Ca²⁺-dependent ion channels and/or Ca²⁺-dependent scramblases. ANO4 which is primarily expressed in the CNS and certain endocrine glands, has been associated with various neuronal disorders. Therefore, we focused our study on prioritizing missense mutations that are assumed to alter the structure and stability of ANO4 protein. We employed a wide array of evolution and structure based in silico prediction methods to identify potentially deleterious missense mutations in the ANO4 gene. Identified pathogenic mutations were then mapped to the modeled human ANO4 structure and the effects of missense mutations were studied on the atomic level using molecular dynamics simulations. Our data show that the G80A and A500T mutations significantly alter the stability of the mutant proteins, thus providing new perspective on the role of missense mutations in ANO4 gene. Results obtained in this study may help to identify disease associated mutations which affect ANO4 protein structure and function and might facilitate future functional characterization of ANO4.