Human Milk Oligosaccharides as Promising Antivirals

Human milk oligosaccharides (HMOs) are diverse unconjugated carbohydrates that are highly abundant in human breast milk. These glycans are investigated in the context of exhibiting multiple functions in infant growth and development. They seem to provide protection against infectious diseases, including a number of poorly manageable viral infections. Although the potential mechanism of the HMO antiviral protection is rather broad, much of the current experimental work has focused on studying of HMO antiadhesive properties. HMOs may mimic structures of viral receptors and block adherence to target cells, thus preventing infection. Still, the potential of HMOs as a source for new antiviral drugs is relatively unexploited. This can be partly attributed to the extreme complexity of the virus‐carbohydrate interactions and technical difficulties in HMO isolation, characterization, and manufacturing procedures. Fortunately, we are currently entering a period of major technological advances that have enabled deeper insights into carbohydrate mediated viral entry, rational selection of HMOs as anti‐entry inhibitors, and even evaluation of individual synthetic HMO structures. Here, we provide an up‐to‐date review on glycan binding studies for rotaviruses, noroviruses, influenza viruses, and human immunodeficiency viruses. We also discuss the preventive and therapeutic potential of HMOs as anti‐entry inhibitors and address challenges on the route from fundamental studies to clinical trials.     

Virtual characterization of MDF fiber network

A virtual design method for medium density fiberboards (MDF) is proposed with the aim to optimize the fiber orientation and lay-up of MDF. The new method estimates the stiffness and strength by using microstructure models of the MDF fiber network. The virtual design is used to improve the manufacturing technology of MDF plates with multilayer oriented fiber structure. Experimental investigations of the mechanical behavior of MDF microstructure for various fiber geometries, glue content and distribution are complicated, time consuming and expensive. On the other side, virtual microstructure design allows to develop a new wood fiber based material with less experimental work. Microstructure models help to better understand the non-linear damage mechanical behavior of a wood fiber network depending on fiber geometrical parameters. Such parameters as crack distribution and fiber deformation on micro-scale level are complicated to experimentally measure, but possible to model using computer simulations. The virtual design tool requires less empirical data. The model takes into account information on average wood fiber orientation, fiber diameter, fiber length and mechanical properties of wood fiber cell wall and glue. The numerical method for strength and stiffness analysis of MDF microstructure was calibrated using standard MDF with non-oriented fibers. It turned out that this method gives precise results for MDF with oriented fibers and even with multilayer structure. The proposed virtual microstructure design tool can significantly improve and speed-up the optimization manufacturing technology of MDF and other wood fiber based composites.     

High-resolution tomographic imaging of a human cerebellum: comparison of absorption and grating-based phase contrast

Human brain tissue belongs to the most impressive and delicate three-dimensional structures in nature. Its outstanding functional importance in the organism implies a strong need for brain imaging modalities. Although magnetic resonance imaging provides deep insights, its spatial resolution is insufficient to study the structure on the level of individual cells. Therefore, our knowledge of brain microstructure currently relies on two-dimensional techniques, optical and electron microscopy, which generally require severe preparation procedures including sectioning and staining. X-ray absorption microtomography yields the necessary spatial resolution, but since the composition of the different types of brain tissue is similar, the images show only marginal contrast. An alternative to absorption could be X-ray phase contrast, which is known for much better discrimination of soft tissues but requires more intricate machinery. In the present communication, we report an evaluation of the recently developed X-ray grating interferometry technique, applied to obtain phase-contrast as well as absorption-contrast synchrotron radiation-based microtomography of human cerebellum. The results are quantitatively compared with synchrotron radiation-based microtomography in optimized absorption-contrast mode. It is demonstrated that grating interferometry allows identifying besides the blood vessels, the stratum moleculare, the stratum granulosum and the white matter. Along the periphery of the stratum granulosum, we have detected microstructures about 40 µm in diameter, which we associate with the Purkinje cells because of their location, size, shape and density. The detection of individual Purkinje cells without the application of any stain or contrast agent is unique in the field of computed tomography and sets new standards in non-destructive three-dimensional imaging.     

Damascene Light‐Weight Metals

Besides widely investigated severely plastically deformed materials that are available in laboratory scale and size only, there is a high demand for semi‐finished products such as sheets and wires with similar mechanical properties. A damascene‐like technology applying swaging and bundling/swaging allows to deform Ti? Nb? Al composites up to a log. deformation strain of 8.4. Here, Al and Ti are used because of their low density, while Nb acts as diffusion barrier to prevent the formation of hardly deformable intermetallic phases. The obtained wires show an ufg microstructure with grain sizes of Ti and Al between 100 and 200 nm. In the cold‐worked condition the wires with a density of 4.0 g cm^?3 reveal an ultimate tensile strength of 790 MPa.     

Thermoplastic elastomers with multi-walled carbon nanotubes: Influence of dispersion methods on morphology

PBT-block-PTMO thermoplastic elastomers derived from dimethyl terephthalate (DMT), 1,4-butanediol(BD) and poly(tetramethylene glycol) (PTMG) were synthesized in the presence of oxidized multi-walled carbon nanotubes (MWCNTs) by a two-stage process involving transesterification and in situ polycondensation. Two procedures were applied to nanotubes in the polymer matrices were used. In procedure 1, nanotubes were dispersed in DMT + BD before the transesterification, while in procedure 2 nanotubes were dispersed in PTMG after transesterification. The mole ratio of the starting components was selected to produce copolymers with a constant hard to soft segment weight ratio of 45:55. Characterization of the new nanocomposites was performed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), small- and wide-angle X-ray scattering (SAXS/WAXS). A better nanotube dispersion can be achieved when oxidized MWCNTs are added to the DMT + BD monomers before transesterification (procedure 1). Oxidized MWCNTs exhibit strong interfacial adhesion to the polymer matrix for both procedures.     

Holzoberflächenmodifikation mittels Atmosphärendruckplasma

Plasma surface modification of wood and wood‐based materials In this article, plasma technical, analytical and application relevant aspects of the plasma treatment of wood and wood‐based materials are presented. With the help of surface energy determinations and adhesion tests it is shown that the surfaces of wood and wood‐based materials can be changed for specific applications. Surface characteristics, which are application‐technological interesting for a later coating or adhesion, can be specifically generated with the use of air plasma. With surface energy determinations of wood and wood‐based materials, a significantly increased polar part of surface energy could be detected after a plasma treatment. Atomic force microscopy analyses of wood composites show that a plasma treatment with the use of ambient air effects an abrasion and a changed surface roughness. Tensile tests and shear tests of coated or adhered wood‐based materials with a plasma treatment show a clearly increased adherence.     

3D-Quantification of the distribution of continuous fibres in unidirectionally reinforced composites

Synchrotron microtomography is carried out for continuous C-fibre reinforced aluminium and a continuous C-reinforced polymer. The local volume fraction as well as the orientation distribution of the reinforcement are analysed three dimensionally for both composites using self-developed calculation methods. Representative elements for the analysis of the local volume fraction are determined by using two-point probability functions. The results show that regions with smaller volume fractions tend to form channels along the fibre bundles for both composites. Channels of high volume fractions, representing touching fibres (local volume fraction >55 vol%), are identified for the polymer matrix composite. The regions with high volume fraction >50 vol% tend to form clusters in the case of the metal matrix composite. The orientation of the reinforcement is followed throughout the volume of both composites. The results show preferential orientations within each bundle of the fibre reinforced metal. The orientation of the reinforcement is more homogeneous in the fibre reinforced polymer and the largest misorientations are found within the channels separating fibre bundles. The characterisation methods developed in this work can be used to evaluate quality criteria adopted in the stage of development of the composites.     

Hydroxyapatite/SiO2 Composites via Freeze Casting for Bone Tissue Engineering

Freeze casting is a fabrication method that allows producing near‐net‐shaped ceramics with variable porosity. Hydroxyapatite (HA) was modified by the addition of different amounts of SiO₂ nanoparticles during freeze cast preparation. The addition of SiO₂ introduced a partial phase transformation of HA to β‐tricalcium phosphate and improved the form stability due to less shrinkage after sintering. The impact of surface roughness of pure HA ceramics and the influence of SiO₂ introduction during freeze casting on adhesion, proliferation, and differentiation of human osteoblast‐like cells (MG‐63) was investigated. While both cell attachment and proliferation of smooth pressed HA was significantly enhanced compared to rough freeze cast HA, the addition of SiO₂ improved the cell numbers of the latter. The expression of cell differentiation markers osteocalcin and collagen I was found to be supported by rough surfaces (R_a = 5–6 µm) in particular on ceramics containing SiO₂