Thermal-Disrupting Interface Mitigates Intercellular Cohesion Loss for Accurate Topical Antibacterial Therapy

Bacterial infections remain a leading threat to global health because of the misuse of antibiotics and the rise in drug-resistant pathogens. Although several strategies such as photothermal therapy and magneto-thermal therapy can suppress bacterial infections, excessive heat often damages host cells and lengthens the healing time. Here, a localized thermal managing strategy, thermal-disrupting interface induced mitigation (TRIM), is reported, to minimize intercellular cohesion loss for accurate antibacterial therapy. The TRIM dressing film is composed of alternative microscale arrangement of heat-responsive hydrogel regions and mechanical support regions, which enables the surface microtopography to have a significant effect on disrupting bacterial colonization upon infrared irradiation. The regulation of the interfacial contact to the attached skin confines the produced heat and minimizes the risk of skin damage during thermoablation. Quantitative mechanobiology studies demonstrate the TRIM dressing film with a critical dimension for surface features plays a critical role in maintaining intercellular cohesion of the epidermis during photothermal therapy. Finally, endowing wound dressing with the TRIM effect via in vivo studies in S. aureus infected mice demonstrates a promising strategy for mitigating the side effects of photothermal therapy against a wide spectrum of bacterial infections, promoting future biointerface design for antibacterial therapy.     

Through Process Modelling of Surface Densified PM Gears

Through process modelling of surface densified gears produced by powder metallurgy (PM) was established by coupling the modelling of the manufacturing processes surface densification, carburization, and heat treatment. The complete model allows the prediction of the local microstructure and hardness in the gear as well as the appearance and direction of residual stresses in the final part. The structural integrity of the part is governed, on the one hand, by the local material properties and residual stresses and, on the other hand, by the load stresses calculated for typical operating conditions. A simplified hardness dependent Haigh diagram was used to calculate the maximum allowable cyclic stresses for the gear tooth and to derive a local utilization ratio as target entity for optimization of the individual steps of the production chain.     

Contribution of peptides and polyphenols from olive water to acrylamide formation in sterilized table olives

To confirm the role of peptides as principal precursors of acrylamide formation in sterilized table olives, peptides from olive water were fractionated. After their partial fractionation by solid phase extraction (SPE) and ultrafiltration (<10,000 Da), respectively, small peptides from olive water were isolated by size-exclusion chromatography (SEC). In the fractions collected, peptides and polyphenolic compounds were determined colorimetrically, and acrylamide was quantitated by LC–MS/MS after heating of the samples. Subsequently, peptides were characterized by matrix-assisted laser desorption/ionization-tandem time of flight mass spectrometry (MALDI-TOF/TOF-MS), and polyphenols were analyzed by LC–MS in the respective fractions. Finally, peptides containing fractions were purified on a polymeric resin (Amberlite XAD 16HP) to remove unbound phenolic compounds by adsorption. The results of the different experiments performed in complete absence of free asparagine and reducing sugars strongly support small peptides bound to polyphenols to be the principal precursors of acrylamide in sterilized table olives.     

Bioaccessibility of carotenoids from plant and animal foods

The frequent consumption of carotenoid-rich foods has been associated with numerous health benefits, such as the supply of provitamin A. To exert these health benefits, carotenoids need to be efficiently liberated from the food matrix, micellized in the small intestine, taken up by the enterocytes and absorbed into the human blood stream. Enormous efforts have been made to better understand these processes. Because human studies are costly, labor-intense and time-consuming, the evaluation of carotenoid liberation and micellization at the laboratory scale using simulated in vitro digestion models has proven to be an important tool for obtaining preliminary results prior to conducting human studies. In particular, the liberation from the food matrix and the intestinal micellization can be mimicked by simulated digestion, yielding an estimate of the so-called bioaccessibility of a carotenoid. In the present review, we provide an overview of the carotenoid digestion process in vivo, the currently used in vitro digestion models and the outcomes of previous bioaccessibility studies, with a special focus on correlations with concomitantly conducted human studies. Furthermore, we advocate for the on-going requirement of better standardized digestion protocols and, in addition, we provide suggestions for the complementation of the acquired knowledge and current nutritional recommendations. © 2018 Society of Chemical Industry     

Impact of enzymatic mash maceration and storage on anthocyanin and color retention of pasteurized strawberry purées

Strawberry purées were prepared using a commercial polygalacturonase (PG) and a highly purified pectinesterase (PE) preparation, respectively. To elucidate the effect of pectin on color stability following enzymatic pulp maceration, pectin composition was studied by isolating and fractionating the alcohol-insoluble residue from the strawberry purées. The purées were stored at +20 and +4 °C in the dark over a period of 24 weeks monitoring the amounts of monomeric and polymeric anthocyanins as well as antioxidant activities (FRAP, TEAC). Individual anthocyanins were analyzed by HPLC–DAD–MS ⁿ , and color measurements were obtained in the CIE L*a*b* system. Pectin composition was significantly modified following enzymatic maceration of the purées. While PG treatment generally resulted in pectin losses, oxalate-soluble pectins were increased in PE-treated purées. After 24 weeks of storage, the best anthocyanin retention was observed in PE-treated purées. Such products also revealed greatest anthocyanin half-life values and lowest proportion of polymeric pigments. Compared to an untreated control, enzymatic purée maceration using the PG was also beneficial for pigment retention, but less effective than PE. In contrast, color and antioxidant activity were independent of both enzymatic treatments. An initial heating step (90 °C, 10 s) for immediate inactivation of native enzymes such as polyphenoloxidases slightly improved pigment stability, while lowered temperature during mash maceration was less effective. However, by far best color and pigment retention were achieved when the purées were stored at 4 °C in the dark.