2D and 3D Micropatterning of Mussel-Inspired Functional Materials by Direct Laser Writing

This work addresses the critical need for multifunctional materials and substrate-independent high-precision surface modification techniques that are essential for advancing microdevices and sensing elements. To overcome existing limitations, the versatility of mussel-inspired materials (MIMs) is combined with state-of-the-art multiphoton direct laser writing (DLW) microfabrication. In this way, 2D and 3D MIM microstructures of complex designs are demonstrated with sub-micron to micron resolution and extensive post-functionalization capabilities. This study includes polydopamine (PDA), mussel-inspired linear, and dendritic polyglycerols (MI-lPG and MI-dPG), allowing their direct microstructure on the substrate of choice with the option to tailor the patterned topography and morphology in a controllable manner. The functionality potential of MIMs is demonstrated by successfully immobilizing and detecting single-stranded DNA on MIM micropattern and nanoarray surfaces. In addition, easy modification of MIM microstructure with silver nanoparticles without the need of any reducing agent is shown. The methodology developed here enables the integration of MIMs in advanced applications where precise surface functionalization is essential

Long-Time Behavior of Surface Properties of Microstructures Fabricated by Multiphoton Lithography

The multiphoton lithography (MPL) technique represents the future of 3D microprinting, enabling the production of complex microscale objects with high precision. Although the MPL fabrication parameters are widely evaluated and discussed, not much attention has been given to the microscopic properties of 3D objects with respect to their surface properties and time-dependent stability. These properties are of crucial importance when it comes to the safe and durable use of these structures in biomedical applications. In this work, we investigate the surface properties of the MPL-produced SZ2080 polymeric microstructures with regard to the physical aging processes during the post-production stage. The influence of aging on the polymeric microstructures was investigated by means of Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS). As a result, a time-dependent change in Young’s Modulus, plastic deformation, and adhesion and their correlation to the development in chemical composition of the surface of MPL-microstructures are evaluated. The results presented here are valuable for the application of MPL-fabricated 3D objects in general, but especially in medical technology as they give detailed information of the physical and chemical time-dependent dynamic behavior of MPL-printed surfaces and thus their suitability and performance in biological systems.DFG, 457594480, Funktionale Polymer- und Nanokomposit-3D-Architekturen mittels Multi-PhotonenLaserstrukturierung für hochentwickelte Anwendungen in MikrobauelementenDFG, 232311024, Wirkprinzipien nanoskaliger Matrixadditive für den Faserverbundleichtba

Desenvolvimento prático de projetos de segurança da informação no Instituto Federal de Educação de Rondônia – Campus Ariquemes / Practical development of information security projects at the Federal Institute of Education of Rondônia – Campus Ariquemes

O presente artigo relata como foram criados e executados projetos de extensão sobre temas relacionados à segurança da informação, no curso técnico em manutenção e suporte em informática, do Campus Ariquemes, do Instituto Federal de Educação, Ciência e Tecnologia de Rondônia. O objetivo foi verificar se os discentes do ensino médio técnico seriam capazes de, sobre orientação de um professor da área, elaborar e executar um projeto prático, sobre os temas, criptografia, engenharia social, SQL Injection WannaCry, dentre outros, apresentando-os e demonstrando a sua prática em uma palestra aberta à comunidade em geral. Os discentes foram alocados em grupos, onde receberam um tema específico, escreveram o projeto, aprenderam a utilizar as tecnologias pertinentes aos temas, criaram apresentações de slides e apresentaram o tema em evento do Campus, demonstrando de forma prática a sua execução, obtendo sucesso nas suas atividades

A Simple Double-Spin Closed Method for Preparing Platelet-Rich Plasma

Objective: To describe and analyze a new protocol for the extraction of platelet-rich plasma (PRP) for use in clinical practice and compare this technique with methods that have been previously described in the medical literature. Methods: Sixteen blood samples from healthy volunteers were collected. PRP was prepared using our new double-spin technique, consisting of successive centrifugation of blood samples with two different spins, without opening the container. Descriptive analysis of cell counts in baseline and PRP samples was undertaken. Comparison between cell and platelet count in baseline and PRP samples, as well as the statistical analysis, were done. Results: The mean platelet concentration ratio was 3.47 (SD: 0.85; 95% CI: 3.01-3.92; range: 2.48-5.71). The baseline whole blood platelet count correlated positively to the PRP platelet count (rP = 0.56; 95% CI: 0.09- 0.88; P = 0.023). The PRP was enriched for lymphocytes and monocytes but presented significantly lower counts of neutrophils and eosinophils in comparison to baseline. Conclusion: Results show a safe and easily reproducible method to obtain PRP for use in clinical daily practice.info:eu-repo/semantics/publishedVersio

Environmental effects of ozone depletion, UV radiation and interactions with climate change : UNEP Environmental Effects Assessment Panel, update 2017

Peer reviewe

Photodégradation de nanocomposites à matrice polymère pour l'encapsulation des cellules solaires organiques

The goal of this work was to develop EVOH/zeolite nanocomposites based on inorganic fillers such as zeolites for potential encapsulation of OSCs and to investigate their photochemical behaviour. The research was focused on the photooxidation mechanism of pristine EVOH copolymers and on the impact of the filler addition on this mechanism. EVOH/zeolite nanocomposites functional properties were characterised taking into account different particle sizes and filler contents. Properties of EVOH copolymers and EVOH/zeolites nanocomposites such as optical transparency, surface morphology, mechanical and thermal properties, and water uptake properties were investigated. On the basis of obtained results, the best candidate(s) for encapsulation of organic solar cells has been proposed. The chemical degradation mechanism of pristine polymers has been proposed, the materials photostability and the impact of the zeolite particles on the photochemical behaviour of the polymer have been studied. Electrical calcium test and performance of encapsulated OSCs were carried out in order to evaluate the ability of the studied materials to be used as potential candidates for efficient and stable encapsulation coatings for OSCs applications.L'objectif de ce travail était le développement des nanocomposites d’EVOH/zeolites à base de charges telles que les zéolites pour l’encapsulation des cellules solaires organiques, et l’étude de leur comportement photochimique. Ce travail a porté sur l’étude du mécanisme de photooxydation des copolymères d’EVOH puis sur l'impact des zéolites sur ce mécanisme. Les propriétés fonctionnelles des nanocomposites d’EVOH/zéolites ont été étudiées en prenant en compte le taux de charge et la taille des particules. Les propriétés des copolymères d’EVOH et des nanocomposites d’EVOH/zéolites comme la transparence optique, la morphologie de surface, les propriétés mécaniques et thermiques, et les propriétés d'absorption de l'eau ont été étudiées. Sur la base des résultats obtenus, les meilleurs candidats pour l'encapsulation des cellules solaires organiques ont été proposés. Le mécanisme de photooxydation des copolymères a été proposé, la photostabilité des matériaux et l'impact des zéolites sur le comportement photochimique du polymère ont été étudiés. Le test électrique de calcium et le suivi des performances des cellules solaires organiques encapsulées ont été effectués afin d'évaluer l’efficacité des matériaux étudiés comme candidats potentiels pour une encapsulation efficace et stable des cellules solaires

Influence of zeolite nanoparticles on photostability of ethylene vinyl alcohol copolymer (EVOH).

International audienceNew ethylene vinyl alcohol copolymer EVOH nanocomposites based on zeolite particles were processed by solution or melt-mixing to synthesise potential encapsulants for flexible organic solar cells (OSC). The photochemical behaviour of pristine EVOH copolymer and the influence of zeolite particles with different size and increasing nanoparticle loading were studied to evaluate the photostability of such packaging materials. Photooxidation of pristine EVOH films (with two different ethylene unit contents (27% or 44%) was performed under accelerated artificial conditions that allow for the proposal of a comprehensive mechanism of EVOH oxidation. The photochemical behaviour of EVOH/zeolite nanocomposites with different morphology and size of particles was compared, revealing a higher oxidation of the polymer in the presence of zeolite particles, which can be mainly attributed to iron impurities

Boehmite Nanofillers in Epoxy Oligosiloxane Resins: Influencing the Curing Process by Complex Physical and Chemical Interactions

In this work, a novel boehmite (BA)-embedded organic/inorganic nanocomposite coating based on cycloaliphatic epoxy oligosiloxane (CEOS) resin was fabricated applying UV-induced cationic polymerization. The main changes of the material behavior caused by the nanofiller were investigated with regard to its photocuring kinetics, thermal stability, and glass transition. The role of the particle surface was of particular interest, thus, unmodified nanoparticles (HP14) and particles modified with p-toluenesulfonic acid (OS1) were incorporated into a CEOS matrix in the concentration range of 1−10 wt.%. Resulting nanocomposites exhibited improved thermal properties, with the glass transition temperature (Tg) being shifted from 30 °C for unfilled CEOS to 54 °C (2 wt.% HP14) and 73 °C (2 wt.% OS1) for filled CEOS. Additionally, TGA analysis showed increased thermal stability of samples filled with nanoparticles. An attractive interaction between boehmite and CEOS matrix influenced the curing. Real-time infrared spectroscopy (RT-IR) experiments demonstrated that the epoxide conversion rate of nanocomposites was slightly increased compared to neat resin. The beneficial role of the BA can be explained by the participation of hydroxyl groups at the particle surface in photopolymerization processes and by the complementary contribution of p-toluenesulfonic acid surface modifier and water molecules introduced into the system with nanoparticles

Long-Time Behavior of Surface Properties of Microstructures Fabricated by Multiphoton Lithography

The multiphoton lithography (MPL) technique represents the future of 3D microprinting, enabling the production of complex microscale objects with high precision. Although the MPL fabrication parameters are widely evaluated and discussed, not much attention has been given to the microscopic properties of 3D objects with respect to their surface properties and time-dependent stability. These properties are of crucial importance when it comes to the safe and durable use of these structures in biomedical applications. In this work, we investigate the surface properties of the MPL-produced SZ2080 polymeric microstructures with regard to the physical aging processes during the post-production stage. The influence of aging on the polymeric microstructures was investigated by means of Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS). As a result, a time-dependent change in Young’s Modulus, plastic deformation, and adhesion and their correlation to the development in chemical composition of the surface of MPL-microstructures are evaluated. The results presented here are valuable for the application of MPL-fabricated 3D objects in general, but especially in medical technology as they give detailed information of the physical and chemical time-dependent dynamic behavior of MPL-printed surfaces and thus their suitability and performance in biological systems

Surface analysis of EVOH and its nanocomposite photoageing: Particles effect

International audienceThe comprehensive study of photoinduced morphological and chemical changes of the surface of ethylene vinyl alcohol copolymer (EVOH) and new EVOH/zeolite nanocomposite as a potential candidate for packaging of flexible electronics was carried out. The films ageing was performed upon accelerated photoageing conditions with low-pressure mercury lamps as a light source. The impact of particles addition was evaluated in terms of surface photochemical behaviour and durability. The morphology data obtained by atomic force microscopy (AFM) and scanning electron microscopy (SEM) were complemented by information collected by time-of-flight secondary ion mass spectrometry (ToF-SIMS), providing high sensitivity and selectivity for database analysis. The combined results showed the complexity of photoageing processes and highlighted significant difference in surface behaviour for plain polymer and nanocomposite. It reflects different evolution of surface morphology with roughness increase for nanocomposite and smoothing in case of plain polymer upon photoageing. This phenomenon was interpreted by the theory of particles accumulation at the surface of the films due to polymer photooxidation and was supported by information on chemical composition at the surface obtained by ToF-SIMS. Evolution of ion peak areas displayed an increase of the particle-related ions at the surface of the films with irradiation time. At the same time, monitoring of different CxHy− and CxHyOz− ions indicated chemical modifications of polymer structure