Seasonality, soil attributes and root biomass in cerrado, cerradão and forest environments, western Amazon

The Amazon rainforest region presents a phytophysiognomy that ranges from savannas to cerrados, all of them intimately associated to climate and soil characteristics. Evidence has been given that plant growth and development are affected by soil quality and seasonality, thus making it crucial to understand them and how they are related to each other in order to grasp the dynamics of the whole ecosystem. In this context, the goal of this research was to assess how seasonality, soil attributes, and root system biomass are related in natural cerrado, cerradão, and forest areas in southern Amazonas State, in Brazil. Soil samples were collected during dry (June/2018) and rainy (December/2018) seasons from three different layers 0.00­0.05m; 0.05­0.15m, and 0.15­0.30m deep. In each area ten sampling points were randomly chosen. Two kinds of soil samples were collected: the first using 4.0 cm height by 5.1cm internal-diameter soil sample rings; and the second were intact soil lumps. Physical and Chemical soil attributes assessed were macro-porosity (MaP), micro-porosity (MiP), total porosity (TP), soil density (SD), aggregates texture and stability (GMD and WAR), gravimetric humidity (HG), organic carbon (OC), exchangeable aluminum (Al3+), potential acidity (H+Al), sum of bases (SB), cation exchange capacity (CEC), and root biomass (RB). All data were analysed via Tukey t test and student T test to compare results between seasons and areas. Increasing vegetation density (cerrado < cerradão < forest) was followed by an increment in CEC and OC, showing the importance of these attributes to maintaining biodiversity in environments. In amazon cerrado, rainy season as well a sandier soil textures provided favourable conditions to the growth and development of plants' root system. Soil attributes were little affected by seasonality, that had greater effect on MiP, TP, SD, and OC, leading to lesser values for these variables during rainy season.

Sistema de fabrico rápido de implantes ortopédicos / Rapid manufacturing system of orthopedics implants

Este estudo teve como objectivo o desenvolvimento uma metodologia de fabrico rápido de implantes ortopédicos, em simultaneidade com a intervenção cirúrgica, considerando duas potenciais aplicações na área ortopédica: o fabrico de implantes anatomicamente adaptados e o fabrico de implantes para substituição de perdas ósseas. A inovação do trabalho desenvolvido consiste na obtenção in situ da geometria do implante, através da impressão directa de um material elastomérico (polivinilsiloxano) que permite obter com grande exactidão a geometria pretendida. Após digitalização do modelo obtido em material elastomérico, o implante final é fabricado por maquinagem recorrendo a um sistema de CAD/CAM dedicado. O implante após esterilização, pode ser colocado no paciente. O conceito foi desenvolvido com recurso a tecnologias disponíveis comercialmente e de baixo custo. O mesmo foi testado sob a forma de uma artroplastia da anca realizada in vivo numa ovelha. O acréscimo de tempo de cirurgia foi de 80 minutos sendo 40 directamente resultantes do processo de fabrico do implante. O sistema desenvolvido revelou-se eficiente no alcance dos objectivos propostos, possibilitando o fabrico de um implante durante um período de tempo perfeitamente compatível com o tempo de cirurgia.

This study, aimed the development of a methodology for rapid manufacture of orthopedic implants simultaneously with the surgical intervention, considering two potential applications in the fields of orthopedics: the manufacture of anatomically adapted implants and implants for bone loss replacement. This work innovation consists on the capitation of the in situ geometry of the implant by direct capture of the shape using an elastomeric material (polyvinylsiloxane) which allows fine detail and great accuracy of the geometry. After scanning the elastomeric specimen, the implant is obtained by machining using a CNC milling machine programmed with a dedicated CAD/CAM system. After sterilization, the implant is able to be placed on the patient. The concept was developed using low cost technology and commercially available. The system has been tested in an in vivo hip arthroplasty performed on a sheep. The time increase of surgery was 80 minutes being 40 minutes the time of implant manufacturing. The system developed has been tested and the goals defined of the study achieved enabling the rapid manufacture of an implant in a time period compatible with the surgery time.