Electrospun silk-elastin-like fiber mats for tissue engineering applications

Protein-based polymers are present in a wide variety of organisms fulfilling structural and mechanical roles. Advances in protein engineering and recombinant DNA technology allow the design and production of recombinant protein-based polymers (rPBPs) with an absolute control of its composition. Although the application of recombinant proteins as biomaterials is still an emerging technology, the possibilities are limitless and far superior to natural or synthetic materials, as the complexity of the structural design can be fully customized. In this work, we report the electrospinning of two new genetically engineered silk-elastin-like proteins (SELPs) consisting of alternate silk- and elastin-like blocks. Electrospinning was performed with formic acid and aqueous solutions at different concentrations without addition of further agents. The size and morphology of the electrospun structures was characterized by scanning electron microscopy showing to be dependent of concentration and solvent used. Treatment with air saturated with methanol was employed to stabilize the structure and promote water insolubility through a time-dependent conversion of random coils into β-sheets (FTIR). The resultant methanol-treated electrospun mats were characterized for swelling degree (570-720%), water vapour transmission rate (1083 g/m2/day) and mechanical properties (modulus of elasticity of ~126 MPa). Furthermore, the methanol-treated SELP fiber mats showed no cytotoxicity and were able to support adhesion and proliferation of normal human skin fibroblasts. Adhesion was characterized by a filopodia-mediated mechanism. These results demonstrate that SELP fiber mats can provide promising solutions for the development of novel biomaterials suitable for tissue engineering applications.

Application to quantify fetal lung branching on rat explants

Recently, regulating mechanisms of branching morphogenesis of fetal lung rat explants have been an essential tool for molecular research. The development of accurate and reliable segmentation techniques may be essential to improve research outcomes. This work presents an image processing method to measure the perimeter and area of lung branches on fetal rat explants. The algorithm starts by reducing the noise corrupting the image with a pre-processing stage. The outcome is input to a watershed operation that automatically segments the image into primitive regions. Then, an image pixel is selected within the lung explant epithelial, allowing a region growing between neighbouring watershed regions. This growing process is controlled by a statistical distribution of each region. When compared with manual segmentation, the results show the same tendency for lung development. High similarities were harder to obtain in the last two days of culture, due to the increased number of peripheral airway buds and complexity of lung architecture. However, using semiautomatic measurements, the standard deviation was lower and the results between independent researchers were more coherent

Estimating Local Part Thickness in Midplane Meshes for Finite Element Analysis

Within the development of motor vehicles, crash safety (e.g. occupant protection, pedestrian protection, low speed damageability), is one of the most important attributes. In order to be able to fulfill the increased requirements in the framework of shorter cycle times and rising pressure to reduce costs, car manufacturers keep intensifying the use of virtual development tools such as those in the domain of Computer Aided Engineering (CAE). For crash simulations, the explicit finite element method (FEM) is applied. The accuracy of the simulation process is highly dependent on the accuracy of the simulation model, including the midplane mesh. One of the roughest approximations typically made is the actual part thickness which, in reality, can vary locally. However, almost always a constant thickness value is defined throughout the entire part due to complexity reasons. On the other hand, for precise fracture analysis within FEM, the correct thickness consideration is one key enabler. Thus, availability of per element thickness information, which does not exist explicitly in the FEM model, can significantly contribute to an improved crash simulation quality, especially regarding fracture prediction. Even though the thickness is not explicitly available from the FEM model, it can be inferred from the original CAD geometric model through geometric calculations. This paper proposes and compares two thickness estimation algorithms based on ray tracing and nearest neighbour 3D range searches. A systematic quantitative analysis of the accuracy of both algorithms is presented, as well as a thorough identification of particular geometric arrangements under which their accuracy can be compared. These results enable the identification of each technique’s weaknesses and hint towards a new, integrated, approach to the problem that linearly combines the estimates produced by each algorithm.

SHACC: a functional prototyper for a component calculus

Over the last decade component-based software development arose as a promising paradigm to deal with the ever increasing complexity in software design, evolution and reuse. SHACC is a prototyping tool for component-based systems in which components are modelled coinductively as generalized Mealy machines. The prototype is built as a HASKELL library endowed with a graphical user interface developed in Swing

Neural Electrode Array Based on Aluminum: Fabrication and Characterization

A unique neural electrode design is proposed with 3 mm long shafts made from an aluminum-based substrate. The electrode is composed by 100 individualized shafts in a 10 × 10 matrix, in which each aluminum shafts are precisely machined via dicing-saw cutting programs. The result is a bulk structure of aluminum with 65 ° angle sharp tips. Each electrode tip is covered by an iridium oxide thin film layer (ionic transducer) via pulsed sputtering, that provides a stable and a reversible behavior for recording/stimulation purposes, a 40 mC/cm2 charge capacity and a 145 Ω impedance in a wide frequency range of interest (10 Hz-100 kHz). Because of the non-biocompatibility issue that characterizes aluminum, an anodization process is performed that forms an aluminum oxide layer around the aluminum substrate. The result is a passivation layer fully biocompatible that furthermore, enhances the mechanical properties by increasing the robustness of the electrode. For a successful electrode insertion, a 1.1 N load is required. The resultant electrode is a feasible alternative to silicon-based electrode solutions, avoiding the complexity of its fabrication methods and limitations, and increasing the electrode performance.

Historical and conceptual landscape of the character

This paper was developed with the intention of broadly demonstrating the complexity of the area known recently as character development, as a creative process methods and implementation. It searches the understanding of the character itself, its place in the narrative and its reception by the reader or target audience. It is a multidisciplinary tool that faces a multitude of challenges from an increasingly demanding public and with specific goals in mind, and yet it also gives us valuable insight over how we interact with one another and the world around us, teaching us how to transfer such knowledge into fiction promoting empathic bonds between the reader and the characters. The human tendency to create is limitless and as old as mankind itself, we create, recreate and reinterpret and then populate such tales with believable characters from who we learn, and experience events and tales that shape our very lives.

Conceptual design of a conveyer system for supporting basic quality of life of bedridden elderly people

With the increasing number of aged people, especially in developed countries, Ambient Assisted Living solutions have become an important subject to be explored and developed. Currently, as specialized Institutions in geriatric care cannot cope with the increasing requests for support of quality of life, patients have to remain at their homes having as caregiver the other member of the couple or a member of close family. A solution for supporting the caregiver, during assisting the bedridden person with some basic tasks as eating, taking a bath and/or hygiene care is of utmost importance. This paper presents an approach for supporting the caregiver in moving and repositioning the bedridden elderly people (BEP) with the assistance of a mechanical system conveyer. The conceptual design of the mechanical system must be devoted to assist the caregiver in the handling and repositioning of the BEP. The proposed mechatronic system must, ideally, minimize the system's handling complexity, reduce the number of caregivers and the amount of spended and needed effort.