Micro- and nanostructured Al2O3 surfaces for controlled vascular endothelial and smooth muscle cell adhesion and proliferation

The effect of the micro- and nanotopography on vascular cell-surface interaction is investigated using nano- and microstructured Al₂O₃ as model substrate. Two different nanostructured Al₂O₃ surfaces composed of low density (LD) and high density (HD) nanowires (NWs) were synthesized by chemical vapour deposition (CVD) and commercially available microstructured Al₂O₃ plates were used for comparison. A clear diverging response of human umbilical vein endothelial cells (HUVEC) and human umbilical vein smooth muscle cells (HUVSMC) was observed on these nano- and microstructured surfaces. LD Al₂O₃ NWs seem to enhance the proliferation of HUVECs selectively. This selective control of the cell-surface interaction by topography may represent a key issue for the future stent material design.     

Wood‐Plastic‐Composites: Rheologische Charakterisierung und Füllverhalten im Spritzgießprozess

Wood‐plastic composites (WPC) show a complex and completely different material and flow behavior in comparison to pure polymers. Especially the flow behavior is very important for the processing of these composites. In the following article results of rheological characterization and investigations of the filling behavior during the injection molding process are presented. Furthermore, appearing challenges and possible methods of resolution are discussed.     

Functional Coupling of Slack Channels and P2X3 Receptors Contributes to Neuropathic Pain Processing

The sodium-activated potassium channel Slack (K_Na1.1, Slo2.2, or Kcnt1) is highly expressed in populations of sensory neurons, where it mediates the sodium-activated potassium current (I_KNa) and modulates neuronal activity. Previous studies suggest that Slack is involved in the processing of neuropathic pain. However, mechanisms underlying the regulation of Slack activity in this context are poorly understood. Using whole-cell patch-clamp recordings we found that Slack-mediated I_KNa in sensory neurons of mice is reduced after peripheral nerve injury, thereby contributing to neuropathic pain hypersensitivity. Interestingly, Slack is closely associated with ATP-sensitive P2X3 receptors in a population of sensory neurons. In vitro experiments revealed that Slack-mediated I_KNa may be bidirectionally modulated in response to P2X3 activation. Moreover, mice lacking Slack show altered nocifensive responses to P2X3 stimulation. Our study identifies P2X3/Slack signaling as a mechanism contributing to hypersensitivity after peripheral nerve injury and proposes a potential novel strategy for treatment of neuropathic pain.     

Enhanced Molecular Alignment in Poly‐l‐Lactic Acid Nanotubes Induced via Melt‐Press Template‐Wetting

Molecular ordering in polymers can have a drastic effect on their properties and can be used to induce or enhance functionality. In the case of poly‐l ‐lactic acid (PLLA), which is a widely used polymer in biomedicine, sensors, and actuators, preferential orientation of chains can lead to significantly enhanced electromechanical properties. In this context, template‐wetting is a straightforward method of producing polymer nanostructures, which can lead to some degree of molecular order in the polymer. Template‐wetting of PLLA has not been fully explored, especially in terms of morphological and/or structural characterization. In this work, PLLA nanotubes are grown via a modification of the template‐wetting process, referred to here as melt‐press template‐wetting. The nanotubes are thoroughly characterized with wide‐angle X‐ray diffraction, isothermal differential scanning calorimetry, and polarized light optical microscopy. This characterization indicates that the polymer chains in these PLLA nanotubes are aligned parallel to the cylindrical axis of the nanotube, which may be beneficial in certain applications.     

Thermoplastic Polyurethane Elastomers with Aliphatic Hard Segments Based on Plant‐Oil‐Derived Long‐Chain Diisocyanates

Novel plant‐oil‐derived long‐chain (C₁₉ and C₂₃) α,ω‐diisocyanates, optionally in combination with the corresponding long‐chain diols, provide entirely aliphatic hard segments in segmented thermoplastic polyurethane elastomers (TPUs), with carbohydrate‐based poly(trimethylene glycol) soft segments. Compared to materials based on a mid‐chain monomer analog, phase separation is higher due to an increased flexibility of the aliphatic segments. Although melting points are slightly lower than for HDPE, the long‐chain TPU's solid‐state structure is still dominated by hydrogen‐bonding.     

Corporate Reputation Effects Across Nations: The Impact of Country Distances and Firm-Specific Resources

CEOs are responsible for the development of a strong corporate reputation, which is increasingly used by multinational corporations as an important differentiation criterion in foreign markets. Because the effects of an often centrally managed but locally perceived reputation are likely to vary between countries, this study analyzes the moderating role of institutional distance and firm-specific resources on reputation effects in the chemical and pharmaceutical industry, two important aspects that have not been considered in consumer-centered corporate reputation research so far. The authors refer to signaling theory—advanced by institutional and resource-based thinking—and use data from 29,987 consumer evaluations of a multinational corporation in 43 countries. The results of the multilevel models indicate that distance between home and host countries weakens reputation effects on both consumer loyalty and trust, whereas firm-specific resources reinforce these effects. In particular, country experience and cultural-cognitive distance are important when managing reputations across nations because they explain high amounts of country-level variance.