Determination of Carbohydrate‐Binding Preferences of Human Galectins with Carbohydrate Microarrays

Galectins are a class of carbohydrate‐binding proteins named for their galactose‐binding preference and are involved in a host of processes ranging from homeostasis of organisms to immune responses. As a first step towards correlating the carbohydrate‐binding preferences of the different galectins with their biological functions, we determined carbohydrate recognition fine‐specificities of galectins with the aid of carbohydrate microarrays. A focused set of oligosaccharides considered relevant to galectins was prepared by chemical synthesis. Structure–activity relationships for galectin–sugar interactions were determined, and these helped in the establishment of redundant and specific galectin actions by comparison of binding preferences. Distinct glycosylations on the basic lactosyl motifs proved to be key to galectin binding regulation—and therefore galectin action—as either high‐affinity ligands are produced or binding is blocked. High‐affinity ligands such as the blood group antigens that presumably mediate particular functions were identified.     

Paradigm change: small machine tools for small workpieces

To overcome current limitations in micro manufacturing a new approach instead of evolutionary small step progress has to take place. Applying small machine tools to manufacture small workpieces allows for a leap of improvements enabled by the small size itself. This miniaturization in comparison to simply down-scaling current concepts qualifies the use of materials and technologies commonly not found in machine tools. This contribution describes the aspects, methodology, qualifications as well as cause and effects pursued by the approach of small machine tools for small workpieces.     

Evaluation of an internally spring preloaded four contact-points bearing for spindle units

In this paper, the concept of an internally spring preloaded four contact-points bearing for the use in high precision and high speed applications is investigated. It is designed as a compact self-contained fixed bearing unit that is free of play, easy to mount and resistant against temperature differences between the inner and outer ring. The concept of the bearing, its functionality and properties are introduced and the results of an experimental analysis of a first prototype are presented. The prototype bearing, which is based on a hybrid 7014 spindle bearing with an additional spring preload unit, was manufactured by hard turning. Its properties are compared to those of similar two and three contact-points spindle bearings. Typical requirements in modern high precision applications, e.g. machine tool spindle units, and limiting characteristics of bearings, such as displacement, stiffness, friction torque and operating temperature, are considered. Finally, the potential of the new bearing concept is discussed.     

In situ analysis of the strain evolution during welding using low transformation temperature filler materials

ABSTRACT

Compared to conventional welding consumables using low transformation temperature (LTT) filler materials is an innovative method to mitigate tensile residual stresses due to delayed martensite transformation of the weld. For the effective usage of LTT filler materials, a deeper understanding of the complex processes that lead to the final residual stress state during multi-pass welding is necessary. Transformation kinetics and the strain evolution of multi-pass welds during welding were investigated in situ at the beamline HEMS@PETRAIII, Germany. Compared to conventional welds, the total strain was reduced and compression strain was achieved when using LTT filler materials. For an optimal use of the LTT effect in the root of multi-pass welds, the alloying concept must be adapted taking care of dilution.     

Strain-induced internal fibrillation in looped aramid filaments

By mapping the small-angle X-ray scattering (SAXS) from a looped poly-(para-phenylene terephtalamide) (aramid, PPTA) filament using a synchrotron X-ray microbeam, we investigate the effects of axially compressive and tensile strain on internal fibrillar structures. Unique observations of oscillations in the highly anisotropic SAXS patterns indicate a regular internal structure. Upon increase of the applied compressive strain, a significant decrease in oscillation frequency is observed in the scattering pattern. With an increase in imposed tensile strain an increase in oscillation frequency in the scattering pattern is observed. One model capable of describing the intensity is a model of stacked cylinders. These cylinders could be part of the fibrillar structure present in the PPTA fibres, which consist of cylinder- to tape-like objects, the presence of which is supported by SEM images. One hypothetical physical interpretation presented here for the appearance of a regular internal structure is the occurrence of fibrillar separation in regions undergoing axially compressive strain, and the appearance of strain relief/slip planes between packs of fibrils in regions undergoing tensile strain. Compaction of these packs upon increase of tensile strain could increase the repetition distance in the structure as multiple packs combine to form a single pack.     

Luminescent Amphiphilic Aminoglycoside Probes to Study Transfection

We report the characterization of amphiphilic aminoglycoside conjugates containing luminophores with aggregation-induced emission properties as transfection reagents. These inherently luminescent transfection vectors are capable of binding plasmid DNA through electrostatic interactions; this binding results in an emission “on” signal due to restriction of intramolecular motion of the luminophore core. The luminescent cationic amphiphiles effectively transferred plasmid DNA into mammalian cells (HeLa, HEK 293T), as proven by expression of a red fluorescent protein marker. The morphologies of the aggregates were investigated by microscopy as well as ζ-potential and dynamic light-scattering measurements. The transfection efficiencies using luminescent cationic amphiphiles were similar to that of the gold-standard transfection reagent Lipofectamine® 2000.     

Hydroisomerization of Renewable and Fossil n-Alkanes over Bifunctional Dealuminated ZSM-5 Catalysts

The hydroisomerization of two long-chain n-alkane mixtures was investigated over bifunctional Pt/H-ZSM-5 catalysts before and after dealumination of preshaped zeolite/binder pellets. The hydroisomerization over the dealuminated catalysts leads to more isomers and less cracking products. Consequently, higher ratios of multi- to mono-branched isomerization products are formed as expected for large- rather than medium-pore zeolites. This indicates a higher availability of space in the vicinity of the active sites and provides an attractive route to make medium-pore zeolites suitable for upgrading higher boiling hydrocarbon feeds.     

Application of Polyimide-based Microfluidic Devices on Acid-catalyzed Hydrolysis of Dimethoxypropane

Microfluidic devices intensify transport phenomena and can improve chemical processes. New manufacturing processes and materials are perpetually developed due to constantly growing interest in process intensification. In this contribution, the authors present the design and application of polyimide-foil-based microfluidic mixing devices manufactured by reactive ion etching. As appropriate model reaction system, acid-catalyzed 2,2-dimethoxypropane (DMP) hydrolysis was chosen and investigated in three different mixing structure with varying flow rate. Energy dissipation rates were calculated to estimate mixing performances. The results show good mixing quality for Reynolds numbers between 10 and 100 and similar mixing times scales for all investigated microstructured mixers.     

NaWuReT-Workshop: Forschung in der Reaktionstechnik für und mit der Gesellschaft

In this article, the results of the NaWuReT (Early Career Reaction Engineers) workshop on the topic “Are we doing relevant science?” are presented. The topics “(In)surmountable hurdles for Citizen Scientists in reaction engineering?” and “Circular Economy in reaction engineering with/for society?” were discussed. Therefrom, a variety of ideas and suggestions were extracted.     

Energy Metabolites as Biomarkers in Ischemic and Dilated Cardiomyopathy

With more than 25 million people affected, heart failure (HF) is a global threat. As energy production pathways are known to play a pivotal role in HF, we sought here to identify key metabolic changes in ischemic- and non-ischemic HF by using a multi-OMICS approach. Serum metabolites and mRNAseq and epigenetic DNA methylation profiles were analyzed from blood and left ventricular heart biopsy specimens of the same individuals. In total we collected serum from n = 82 patients with Dilated Cardiomyopathy (DCM) and n = 51 controls in the screening stage. We identified several metabolites involved in glycolysis and citric acid cycle to be elevated up to 5.7-fold in DCM (p = 1.7 × 10⁻⁶). Interestingly, cardiac mRNA and epigenetic changes of genes encoding rate-limiting enzymes of these pathways could also be found and validated in our second stage of metabolite assessment in n = 52 DCM, n = 39 ischemic HF and n = 57 controls. In conclusion, we identified a new set of metabolomic biomarkers for HF. We were able to identify underlying biological cascades that potentially represent suitable intervention targets.