Wound healing is a complex process involving an integrated response by many different cell types and growth factors in order to achieve rapid restoration of skin architecture and function. The present study evaluated the applicability of a chitosan hydrogel (CH) as a wound dressing. Scanning electron microscopy analysis was used to characterize CH morphology. Fibroblast cells isolated from rat skin were used to assess the cytotoxicity of the hydrogel. CH was able to promote cell adhesion and proliferation. Cell viability studies showed that the hydrogel and its degradation by-products are noncytotoxic. The evaluation of the applicability of CH in the treatment of dermal burns in Wistar rats was performed by induction of full-thickness transcutaneous dermal wounds. Wound healing was monitored through macroscopic and histological analysis. From macroscopic analysis, the wound beds of the animals treated with CH were considerably smaller than those of the controls. Histological analysis revealed lack of a reactive or a granulomatous inflammatory reaction in skin lesions with CH and the absence of pathological abnormalities in the organs obtained by necropsy, which supported the local and systemic histocompatibility of the biomaterial. The present results suggest that this biomaterial may aid the re-establishment of skin architecture.

Introduction European Commission has promoted actions and policies with the aim of reducing the negative impacts on traffic and environment caused by city logistics. One increasingly popular measure is the use of cargo bikes in city logistics due to their improved energy efficiency, lower emissions and lower traffic disturbance. The paper assess the impacts of electric cargo bikes, from a public policy perspective and, simultaneously, taking into account variables that cover the urban logistics operators' interests. Under a public policy perspective, the considered variables evaluate mobility, environmental impacts and indirectly, the quality of life. In terms of private interests, the studied variables cover costs levels (operation and driving) and efficiency. This evaluation aims at clarifying if electric cargo bikes can indeed represent a sustainable mobility policy under specific boundaries, by leading to better environmental and social impacts and not hindering the operational efficiency of urban logistics activities. Methods For that purpose, the measurement of the traffic key performance indicators, as well as of Well-to-Wheel energy and CO 2 emission savings is performed allowing to quantify mobility, reliability and operational efficiency indicators. Several scenarios related with the introduction of electric cargo bikes replacing conventional vans were assessed and evaluated in order to compare the effects of different market shares in the mobility of the studied area located in Porto (Portugal). Acknowledging the short distance range of cargo bikes, the simulation is carried out and an estimation of the total transportation cost is performed, which includes transport and emission cost when the vehicle is driving, emission cost while idling and labor cost. Results The main conclusion is that cargo bikes can replace up to 10% of the conventional vans in areas with maximum linear distances of about 2 km, without changing the overall network efficiency. Additionally, urban logistics WTW CO 2 emission impacts can be reduced by up to 73%, which represents 746 kg of CO 2 avoided emissions. Furthermore, the introduction of electric cargo bikes in urban logistics activities has positive effects for all the vehicle categories and all the scenarios, reaching up to 25% of reductions in external costs. Conclusions As a result, cargo bikes implemented at the appropriate spatial scale within the city can be a sustainable solution for urban logistics, depending on a prior delimitation of the conditions and adequate implementation strategy, to guarantee that it actually leads to improvements in terms of mobility, environment, energy, running costs and externalities.

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