A perfusion decellularization heart model - an interesting tool for cell-matrix interaction studies

Objective. In this paper, we present a technique for whole human, pig, or rat heart decellularization in order to obtain a tool for cell-matrix interaction studies and to obtain the extracellular matrix scaffold with applications to the study of cardiac connective tissue architecture for tissue bioengineering. Material and methods. In order to achieve tissue decellularization we present two separate protocols, the first for large animal hearts (e.g., pig hearts) and human hearts, the second for smaller hearts (e.g., rat hearts). We have performed the cardiac decellularization technique on 20 pig hearts, 5 human hearts, and 20 rat hearts. Results. The decellularization technique on the heart was assessed through histological examination. Conclusion. Although the decellularization technique on the heart is currently under development, this process affords the possibility of developing research in the fields of biomaterials, tissue engineering, and cardiac cell cultures

The operational phase of GMES – a knowledge Earth observation data handling and feature extraction shared platform

Based on experience and components developed in national projects as for example components for land cover and land use monitoring, ROKEO is intended to facilitate knowledge based and interactive learning as a semantic information extraction processes

Automation and Remote Control of an Aquatic Harvester Electric Vehicle

Electric boats are evolving, following the trend of imposing electric powered vehicles in all transportation solutions. For a research project, a reed and aquatic weed harvester, the author’s goal is to develop an experimental electrical vehicle aimed at solving several particular problems such as: small speed, big throttle, high maneuverability, big load capacity, small draught and affordable cost. The solution comprises of one electric motor powered by a converter supplied from Li-Ion batteries, which drives a hydraulic pump for simultaneous operation of two lateral-placed paddle wheels and one complex mechanism of cutter and conveyor. The control system of this vehicle consists of one remote controller, with bidirectional radio communication to three on-board controllers used for the management of the electro-hydraulic actuators, the electric motor and the battery storage system. The hardware and the software architectures are presented, underlining the automated operations designed to increase the safety, the maneuverability and the predictability of the vehicle. The advantages of the use of control electronics is the increasing operability of the vehicle by supervising the available stored energy and the predicted consumption of energy, the fast and remote assistance in case of operational failure using online diagnose and the operation optimization by selecting the best load profile for the cutter and for the paddles. The results of this research are the validation of the proposed hardware and software architectures used for the control of an electro-hydraulic vehicle and the feasibility of using radio communication and remote diagnose for vehicle control

Aging of 3D Printed Polymers under Sterilizing UV-C Radiation

In the context of the COVID-19 pandemic, shortwave ultraviolet radiation with wavelengths between 200 nm and 280 nm (UV-C) is seeing increased usage in the sterilization of medical equipment, appliances, and spaces due to its antimicrobial effect. During the first weeks of the pandemic, healthcare facilities experienced a shortage of personal protective equipment. This led to hospital technicians, private companies, and even members of the public to resort to 3D printing in order to produce fast, on-demand resources. This paper analyzes the effect of accelerated aging through prolonged exposure to UV-C on mechanical properties of parts 3D printed by material extrusion (MEX) from common polymers, such as polylactic acid (PLA) and polyethylene terephthalate-glycol (PETG). Samples 3D printed from these materials went through a 24-h UV-C exposure aging cycle and were then tested versus a control group for changes in mechanical properties. Both tensile and compressive strength were determined, as well as changes in material creep properties. Prolonged UV-C exposure reduced the mechanical properties of PLA by 6–8% and of PETG by over 30%. These findings are of practical importance for those interested in producing functional MEX parts intended to be sterilized using UV-C. Scanning electron microscopy (SEM) was performed in order to assess any changes in material structure

Enhancing Mechanical Properties of Polymer 3D Printed Parts

Parts made from thermoplastic polymers fabricated through 3D printing have reduced mechanical properties compared to those fabricated through injection molding. This paper analyzes a post-processing heat treatment aimed at enhancing mechanical properties of 3D printed parts, in order to reduce the difference mentioned above and thus increase their applicability in functional applications. Polyethylene Terephthalate Glycol (PETG) polymer is used to 3D print test parts with 100% infill. After printing, samples are packed in sodium chloride powder and then heat treated at a temperature of 220 °C for 5 to 15 min. During heat treatment, the powder acts as support, preventing deformation of the parts. Results of destructive testing experiments show a significant increase in tensile and compressive strength following heat treatment. Treated parts 3D printed in vertical orientation, usually the weakest, display 143% higher tensile strength compared to a control group, surpassing the tensile strength of untreated parts printed in horizontal orientation—usually the strongest. Furthermore, compressive strength increases by 50% following heat treatment compared to control group. SEM analysis reveals improved internal structure after heat treatment. These results show that the investigated heat treatment increases mechanical characteristics of 3D printed PETG parts, without the downside of severe part deformation, thus reducing the performance gap between 3D printing and injection molding when using common polymers