Self-assembling Peptides in Current Nanomedicine: Versatile Nanomaterials for Drug Delivery

Background: The development of modern nanomedicine greatly depends on the involvement of novel materials as drug delivery system. In order to maximize the therapeutic effects of drugs and minimize their side effects, a number of natural or synthetic materials have been widely investigated for drug delivery. Among these materials, biomimetic self-assembling peptides (SAPs) have received more attention in recent years. Considering the rapidly growing number of SAPs designed for drug delivery, a summary of how SAPs-based drug delivery systems were designed, would be beneficial. Method: We outlined research works on different SAPs that have been investigated as carriers for different drugs, focusing on the design of SAPs nanomaterials and how they were used for drug delivery in different strategies. Results: Based on the principle rules of chemical complementarity and structural compatibility, SAPs such as ionic self-complementary peptide, peptide amphiphile and surfactant-like peptide could be designed. Determined by the features of peptide materials and the drugs to be delivered, different strategies such as hydrogel embedding, hydrophobic interaction, electrostatic interaction, covalent conjugation or the combination of them could be employed to fabricate SAPs-drug complex, which could achieve slow release, targeted or environment-responsive delivery of drugs. Furthermore, some SAPs could also be combined with other types of materials for drug delivery, or even act as drug by themselves. Conclusion: Various types of SAPs have been designed and used for drug delivery following various strategies, suggesting that SAPs as a category of versatile nanomaterials have promising potential in the field of nanomedicine.

Structural Compatibility of Infrastructures Utilizing Alternative Earth Construction Materials

This paper presents analysis of the structural behavior of road pavements in which alternative construction materials are replacing the traditional ones in some of the structural layers. The analysis is consider important since from the structural performance point of view many of the alternative materials have mechanical properties far different from those of the traditional road construction materials, especially unbound aggregates, and as a consequence of that, the empirically calibrated design rules applied and adjusted for the normally utilized pavements solutions are not valid any more. The analysis is exemplified by means of four different low volume road pavement structures that are in line with the existing design guidelines in Finland. The mechanical behavior of these structures is analyzed using three different approaches: semi-empirical Oedemark design approach, multi-layer linear elastic analysis and finite element analysis. The obtained calculation results indicate clearly that if a low volume road structure containing a high stiffness layer made e.g. of stabilized fly ash is resting on soft subgrade soil, tensile stresses up to 1 MPa may be developed. Therefore, the performance and respective distress mechanisms of the structure are likely to be very different from those of a traditional solution. As a key conclusion from the analysis, need for a new concept, structural compatibility, was identified. It would help in drawing due attention to the mechanical behavior of alternative materials when they are used in replacing the traditional ones in road structures exposed to repeated heavy traffic loads. Graphic Abstract

Using the Post-Descendens Hypoglossal Nerve in Hypoglossal-Facial Anastomosis: An Anatomic and Histologic Feasibility Study

BACKGROUND Hypoglossal-facial anastomosis (HFA) is a popular facial reanimation technique. Mobilizing the intratemporal segment of the facial nerve and using the post-descendens hypoglossal nerve (ie, the segment distal to the take-off of descendens hypoglossi) have been proposed to improve results. However, no anatomic study has verified the feasibility of this technique. OBJECTIVE To assess the anatomic feasibility of HFA and the structural compatibility between the 2 nerves when the intratemporal facial and post-descendens hypoglossal nerves are used. METHODS The facial and hypoglossal nerves were exposed bilaterally in 10 sides of 5 cadaveric heads. The feasibility of a side-to-end (ie, partial end-to-end) HFA with partial sectioning of the post-descendens hypoglossal nerve and the mobilized intratemporal facial nerve was assessed. The axonal count and cross-sectional area of the facial and hypoglossal nerves at the point of anastomosis were assessed. RESULTS The HFA was feasible in all specimens with a mean (standard deviation) 9.3 (5.5) mm of extra length on the facial nerve. The axonal counts and cross-sectional areas of the hypoglossal and facial nerves matched well. Considering the reduction in the facial nerve cross-sectional area after paralysis, the post-descendens hypoglossal nerve can provide adequate axonal count and area to accommodate the facial nerve stump. CONCLUSION Using the post-descendens hypoglossal nerve for side-to-end anastomosis with the mobilized intratemporal facial nerve is anatomically feasible and provides adequate axonal count for facial reanimation. When compared with use of the pre-descendens hypoglossal nerve, this technique preserves C1 fibers and has a potential to reduce glottic complications.

Role of the growth step on the structural, optical and surface features of TiO 2 /SnO 2 composites

TiO 2 /SnO 2 composites have attracted considerable attention for their application in photocatalysis, fuel cells and sensors. Structural, morphological, optical and surface features play a pivotal role in photoelectrochemical applications and are critically related to the synthetic route. Most of the reported synthetic procedures require high-temperature treatments in order to tailor the sample crystallinity, usually at the expense of surface hydroxylation and morphology. In this work, we investigate the role of a treatment in an autoclave at a low temperature (100°C) on the sample properties and photocatalytic performance. With respect to samples calcined at 400°C, the milder crystallization treatment promotes anatase phase, mesoporosity and water chemi/physisorption, while reducing the incorporation of heteroatoms within the TiO 2 lattice. The role of Sn content was also investigated, showing a marked influence, especially on the structural properties. Notably, at a high content, Sn favours the formation of rutile TiO 2 at very low reaction temperatures (100°C), thanks to the structural compatibility with cassiterite SnO 2 . Selected samples were tested towards the photocatalytic degradation of tetracycline in water under UV light. Overall, the low-temperature treatment enables to tune the TiO 2 phase composition while maintaining its surface hydrophilicity and gives rise to well-dispersed SnO 2 at the TiO 2 surface.