Dubious security practices in e-voting schemes Between tech and legal standards

Remote electronic voting has been around for a few decades now. However, some legal uncertainty regarding its uses remains. In this paper, we would like to highlight and discuss several techniques used in e-voting which may not be fully compliant with the law. We analyze several e-voting practices that rely on the addition of dummy ballots and show how they conflict with legal standards. Specifically, we focus on cases where dummy ballots are required for: better performance, testing, participation privacy, or preventing coercion. We argue that these practices may raise issues with the standards of authenticity and eligibility, as well as with the principle “one voter, one vote”. Our research aims to offer a better understanding of how legal principles can be interpreted to ensure the legality of technological proposals in e-voting

Micro- and Nanotexturization of Liquid Silicone Rubber Surfaces by Injection Molding Using Hybrid Polymer Inlays

Micro- and nanotexturization of surfaces can give to the parts different advanced functionalities, such as superhydrophobicity, self-cleaning, or antibacterial capabilities. These advanced properties in combination with the biocompatibility of Liquid Silicone Rubber are an interesting approach for obtaining high-performance medical devices. The industrial production of surface textures in polymeric materials is through the replication technique, and the best option to attain a high production rate is injection molding. Moreover, its low viscosity during processing can provide an accurate replication capacity by the easy filling by capillarity of the microtextures. An innovative replicating technique for Liquid Silicone Rubber is presented by studying the replication of different shaped textures within a diameter range of between 2 and 50 mu m. The copying process consists in the overmolding of a textured polymeric inlay obtained by nanoimprint lithography. At the end of the process, a textured part is obtained, while the imprinted film remains in the mold. The injection molding parameters are optimized to increase the replication accuracy, and their effect on texture replicability is analyzed and discussed. Finally, it is shown that the textured surfaces improve their wettability behavior, which is a necessary and important characteristic in the development of biomedical devices

Medicated Scaffolds Prepared with Hydroxyapatite/Streptomycin Nanoparticles Encapsulated into Polylactide Microfibers

The preparation, characterization, and controlled release of hydroxyapatite (HAp) nanopar-ticles loaded with streptomycin (STR) was studied. These nanoparticles are highly appropriate for the treatment of bacterial infections and are also promising for the treatment of cancer cells. The analyses involved scanning electron microscopy, dynamic light scattering (DLS) and Z-potential measurements, as well as infrared spectroscopy and X-ray diffraction. Both amorphous (ACP) and crystalline (cHAp) hydroxyapatite nanoparticles were considered since they differ in their release behavior (faster and slower for amorphous and crystalline particles, respectively). The encapsulated nanoparticles were finally incorporated into biodegradable and biocompatible polylactide (PLA) scaf-folds. The STR load was carried out following different pathways during the synthesis/precipitation of the nanoparticles (i.e., nucleation steps) and also by simple adsorption once the nanoparticles were formed. The loaded nanoparticles were biocompatible according to the study of the cytotoxicity of extracts using different cell lines. FTIR microspectroscopy was also employed to evaluate the cytotoxic effect on cancer cell lines of nanoparticles internalized by endocytosis. The results were promising when amorphous nanoparticles were employed. The nanoparticles loaded with STR increased their size and changed their superficial negative charge to positive. The nanoparticles’ crystallinity decreased, with the consequence that their crystal sizes reduced, when STR was incorporated into their structure. STR maintained its antibacterial activity, although it was reduced during the adsorption into the nanoparticles formed. The STR release was faster from the amorphous ACP nanoparticles and slower from the crystalline cHAp nanoparticles. However, in both cases, the STR release was slower when incorporated in calcium and phosphate during the synthesis. The biocompatibility of these nanoparticles was assayed by two approximations. When extracts from the nanoparticles were evaluated in cultures of cell lines, no cytotoxic damage was observed at concen-trations of less than 10 mg/mL. This demonstrated their biocompatibility. Another experiment using FTIR microspectroscopy evaluated the cytotoxic effect of nanoparticles internalized by endocytosis in cancer cells. The results demonstrated slight damage to the biomacromolecules when the cells were treated with ACP nanoparticles. Both ACP and cHAp nanoparticles were efficiently encapsulated in PLA electrospun matrices, providing functionality and bioactive properties. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Degradable Poly(ester amide)s for Biomedical Applications

Poly(ester amide)s are an emerging group of biodegradable polymers that may cover both commodity and speciality applications. These polymers have ester and amide groups on their chemical structure which are of a degradable character and provide good thermal and mechanical properties. In this sense, the strong hydrogen‑bonding interactions between amide groups may counter some typical weaknesses of aliphatic polyesters like for example poly(e-caprolactone). Poly(ester amide)s can be prepared from different monomers and following different synthetic methodologies which lead to polymers with random, blocky and ordered microstructures. Properties like hydrophilic/hydrophobic ratio and biodegradability can easily be tuned. During the last decade a great effort has been made to get functionalized poly(ester amide)s by incorporation of a-amino acids with hydroxyl, carboxyl and amine pendant groups and also by incorporation of carbon-carbon double bonds in both the polymer main chain and the side groups. Specific applications of these materials in the biomedical field are just being developed and are reviewed in this work (e.g., controlled drug delivery systems, hydrogels, tissue engineering and other uses like adhesives and smart materials) together with the main families of functionalized poly(ester amide)s that have been developed to date

Melt Electrospinning of Polymers: Blends, Nanocomposites, Additives and Applications

Melt electrospinning has been developed in the last decade as an eco-friendly and solvent-free process to fill the gap between the advantages of solution electrospinning and the need of a cost-effective technique for industrial applications. Although the benefits of using melt electrospinning compared to solution electrospinning are impressive, there are still challenges that should be solved. These mainly concern to the improvement of polymer melt processability with reduction of polymer degradation and enhancement of fiber stability; and the achievement of a good control over the fiber size and especially for the production of large scale ultrafine fibers. This review is focused in the last research works discussing the different melt processing techniques, the most significant melt processing parameters, the incorporation of different additives (e.g., viscosity and conductivity modifiers), the development of polymer blends and nanocomposites, the new potential applications and the use of drug-loaded melt electrospun scaffolds for biomedical applications

Three-level hierarchical micro/nanostructures on biopolymers by injection moulding using low-cost polymeric inlays

The industrial interest in the patterning of polymeric surfaces at the micro/nanoscale to include new functionalities has considerably increased during the last years. Hierarchical organization of micro/nanometric surface textures yields enhanced functional properties such as hydrophobicity, hydrophilicity, antibacterial activity, and optical or chromatic effects to cite some. While high accuracy methods to pattern hierarchical surfaces at the nanoscale have been developed, only some of them have been applied for high volume manufacturing with limited success, mainly because they rely on the use of expensive machinery and moulds or complicated inserts. Therefore, a method using low cost recyclable tooling and process conditions applicable to high-volume manufacturing is currently missing. In this work, a scalable and low-cost method to replicate hierarchical micro/nanostructured surfaces on plastic films is presented, which can be latter used as inlays for injection moulded parts with standard processing conditions. This method is used to demonstrate the feasibility of replicating three level hierarchical micro/nano textured surfaces using recyclable bio-based polymers (of high relevancy in the current plastic pollution context) achieving replication ratios above 90%, comparing the replication results with those obtained in polypropylene. The presence of the micro/nanotextures substantially increases the contact angle of all the polymers tested, yielding values higher than 90° in all the cases. Also, various mechanical properties of the replicated parts for all the polymers injected are characterized one and thirty days after the samples were manufactured, showing fairly constant values. This highlights the validity of the replicated surfaces, regardless of the biopolymers special crystallization characteristics.Peer reviewe

Library of Cationic Polymers Composed of Polyamines and Arginine as Gene Transfection Agents

Combinatorially synthesized materials, especially cationic polymers (CPs), with gene transfection function hold great promise in nanotechnology. However, the main limitations of the existing CPs [such as polyethylenimine (PEI), poly-l-arginine, or polyamidoamine-based dendrimers] as gene transfection agents are high cytotoxicity in the physiological environment. We have developed novel CPs composed of polyamines—endogeneous tetraamine spermine (Spm) and synthetically made triamine N-(2-aminoethyl)-1,3-propanediamine (Apd) for incorporating sec-amino groups and imparting PEI-like structure to the CP backbones. Naturally occurring building blocks such as amino acid arginine (R) was also used for incorporating guanidine-groups into the CPs. The cytotoxicity of resulting CPs—polyureas (PUs) and polyamides such as polysuccinamides and R-attached polymalamides was evaluated using murine and human fibroblasts and carcinoma cell lines. The cell compatibility screening revealed that the CPs made of Apd are less cytotoxic compared to Spm-based analogues. From the novel polymer library, total of six polymers were further studied for oligonucleotide (pDNA) complexation and transfection abilities. Highly water-soluble CPs formed nano-sized polyplexes with pDNA at rather low CP/pDNA weight ratios and showed less cytotoxicity and higher transfection ability compared to widely used PEI as well as commercially available transfection agents. Furthermore, new CPs showed selective transfection activity toward certain cell lines (4T1, HeLa, NIH3T3, and CCD 27SK), which is important for their potential applications in gene therapy.Postprint (published version

Introducing surface functionality on thermoformed polymeric films

We present a fabrication process for the production of 3-dimensional micro-structured polymeric films. The microstructures are fabricated in a single step using thermal nanoimprint lithography as patterning technique. The micro-structured polymer films are then transformed into a 3D shape by means of a plug-assisted thermoforming process, while keeping the functionality of the micro-patterned areas. The preserved functionality is characterized by water contact angle measurements, while the deformation of the micro-structured topographies due to the thermoforming process is analyzed using confocal microscopy and Digital Image Correlation (DIC) techniques. This combined fabrication process represents a promising solution to complement in-mold decoration approaches, enabling the production of new functional surfaces. As the microstructures are fabricated by means of a mechanical modification of the surface, without the need of chemical treatments or coatings, the presented technique represents a promising, simple and green solution, suitable for the industrial fabrication of 3D nonplanar shaped functional surfaces.Peer reviewe