Chitosan microparticles loaded with essential oils having in view leather applications

Chitosan is a biopolymer attracting considerable attention for diverse applications due to its unique properties like biodegradability, biocompability, non-toxicity and antimicrobial activity. It is obtained by the partial N-deacetylation of chitin, which is the second most abundant polysaccharide in nature, next to cellulose. Chitosan is a viable base material for functional coatings development, namely due to its antimicrobial activity. This characteristic is especially useful for footwear applications that constitute products prone to microbial attack. In this context, developing antimicrobial coatings to be used in footwear components in direct contact with the feet are of great interest, both at industrial level (reducing possibility of material deterioration and quality loss), as well as, from the consumer’s point of view (decrease of skin infections and minor unpleasant odours). Following our previous work, where leather impregnation with chitosan was studied at laboratorial level with quite promising results, and having in view the final application (footwear leather components), where the antimicrobial effect must need to be enhanced, we have developed the idea of microencapsulate different essential oils, with recognized antimicrobial activity like lemon, oregano, eucalyptus and pine. These chitosan-based microparticles, loaded with the chosen essential oil are intended to be applied conjunctly with the chitosan coating process previously studied. Microencapsulation will ensure that the loaded core material will be progressively released, reinforcing the antimicrobial durability and effectiveness of the final product.COMPETE, QREN and EU within the project QREN-ADI-1585-ADVANCEDSHO

Chitosan-based leather functional coatings with improved antimicrobial properties

Among the interesting biological activities that have been ascribed to chitosan, the antimicrobial activity is probably the one that generates the higher number of applications. Developing antimicrobial coatings for footwear components to be used in direct contact with the feet is of great interest; both at industrial level (reducing the possibility of material deterioration and quality loss) and from the consumer’s point of view (decreasing skin infections and minimizing unpleasant odours). One weakness of this application is addressed to the durability and efficiency of the product antimicrobial activity, since it is directly associated with the availability of the positively charged R–NH3 + groups that are depleted during use

Chitosan as an antimicrobial agent for footwear leather components

In the footwear industry, microorganisms’ growth can pose problems of material deterioration with associated unpleasant smell and generate possible infections in susceptible individuals. Generally, footwear presents high relative humidity conditions that enable the growth of bacteria and fungi. Additionally, leather itself and some tannery agents such as oils and greases, provide a substrate where microorganisms can grow. In the foot, microtraumas caused by ingrown nails, abrasions and lacerations can allow microbial invasion through epidermis, resulting in skin infection. In this work, the applicability of chitosan functional coatings to leather was tested, with the purpose to develop new base materials to produce footwear components. The leather treated with chitosan was then studied for its antibacterial properties against 3 different bacteria.COMPETE, QREN and EU (project QREN-ADI-1585-ADVANCEDSHOE)

Development of a prototype to access biodegradability of TPU shoe soles under controlled conditions

In the last years, the increasing problems posed by waste management have stimulated the interest in developing more sustainable and bio-based solutions for the footwear industry, including the use of biodegradable materials. As part of the NEWALK project, the objective of this work consisted in optimizing and implementing a respirometry system prototype. Besides evaluating different variables, two different approaches for measuring the evolved CO2 were assayed. Compared to manual titration, the use of conductivity offers the advantage of an automatic continuous monitoring.info:eu-repo/semantics/publishedVersio

The use of bio-based additives (lignin, starch and cellulose) in thermoplastic polyuretane formulations to enhance the biodegradability of footwear components

Thermoplastic polyurethanes (TPUs) are one of the most widely used polymeric materials. They can be used in an extensive range of applications, including automotive, footwear, interior design, adhesives, coatings, textile and biomedical. In what concerns the footwear sector, it is estimated that TPU based components represent about 60% of the whole European production of footwear components [1]. On the other hand, the use of a wide variety of additives in TPU formulations (e.g. pigments, coatings and fillers) limits the possibility of recycling. In such scenario, biodegradable polymers could offer an excellent solution to the environment hazard posed by the conventional materials [2]. Therefore, given the widespread use of TPUs and associated waste management problems, it makes sense to invest on the development of more biodegradable and environmental compatible solutions. For this purpose, the incorporation of bio-based and biodegradable additives is being studied in the last years [2-4]. The incorporation of a biodegradable compound, even at a low content in a TPU formulation, can promote biodegradation. It will constitute a preferential site for microorganisms’ attack thus favouring biodegradation initiation and progression. In this work, a base TPU used in the footwear industry was modified by compounding with three biobased additives (lignin, starch and cellulose). Biodegradability of the resulting materials was evaluated in agar plate tests against the fungi Aspergillus niger ATCC16404, the gram negative bacteria Pseudomonas aeruginosa ATCC9027 and an association of both (consortium). In a second phase soil tests have been also performed.info:eu-repo/semantics/publishedVersio

Screening of different microorganisms for their biodegradation capacity regarding polyester-based thermoplastic polyurethanes

and bio-based solutions in shoe manufacturing, including the use of biodegradable materials. As a first step towards the proposal of such solutions, in this work different microorganisms were screened for their intrinsic capacity to degrade a base TPU. The biodegradability was tested using the agar plate method against different bacteria, fungi and a consortium of both. The most promising results, corresponding to higher weight-loss percentages of the TPU sample, were obtained using the consortium of Pseudomonas aeruginosa and Aspergillus niger. These best conditions were thereafter applied to TPU samples compounded with biobased additives.info:eu-repo/semantics/publishedVersio

Tratamento radiocirúrgico de metástases cerebrais: a relação da histologia, localização cerebral e sintomas

Objetivo – Caracterizar clínica e estatisticamente os doentes com metástases cerebrais submetidos a radiocirurgia. Metodologia – Análise retrospetiva dos doentes com metástases cerebrais submetidos a radiocirurgia com Linac no Hospital do Meixoeiro, sendo a informação analisada no SPSS, versão 18. Resultados – Avaliaram‑se 116 doentes com metástases cerebrais. As localizações primárias de pulmão (54,30%) e mama (21,60%) predominaram. Destacaram‑se como sintomas mais frequentes: cefaleias, fraqueza motora, hemiparesia, paresia e tonturas. Confirma‑se a existência de correlação entre os sintomas decorrentes da presença de metástase e a sua localização cerebral, evidenciando a sua importância no diagnóstico precoce das metástases. O lobo frontal foi a localização cerebral predominante. Discussão e Considerações Finais – Verifica‑se que tendencialmente não existe correlação entre a localização primária e a localização cerebral da metástase. O número de metástases tratadas não sugere ter influência no tempo de sobrevida após o seu diagnóstico. A realização de cirurgia e/ou administração de radioterapia holocraniana previamente à radiocirurgia não apresentou prolongamento de sobrevida em comparação com os doentes não submetidos a tratamento prévio. ABSTRACT: Objective – To characterize clinically and statistically patients with brain metastases who underwent radiosurgery. Methodology – Retrospective analysis of patients with brain metastases that underwent linear accelerator‑based radiosurgery in Hospital do Meixoeiro, and the information analyzed in SPSS version 18. Results – Were evaluated 116 patients with brain metastases. Primary tumors of lung (54.30%) and breast (21.60%) were predominant. Symptoms that stood out as common: headache, motor deficit, hemiparesis, paresis and dizziness. It was confirmed the existence of a correlation between the symptoms arising from the presence of metastasis and its brain location, showing its importance in early diagnosis of metastases. The frontal lobe and the parietal lobe represented the most affected locations by brain metastases. Discussion of results and Concluding Remarks – It verified that tends to be no correlation between the primary location of the tumor and the location of brain metastasis. The number of treated metastases didn’t suggest influence on survival after their diagnosis. The realization of surgery and/or administration of whole‑brain irradiation therapy prior to radiosurgery, showed no prolongation of survival compared with patients that were not submitted to previous treatment

Assessement of Malaria Transmission in an Area with Very Low Mosquito Density

The increase in world travel in recent years, especially to and from areas where vector-borne diseases are endemic, has resulted in a substantial rise in imported cases of those diseases. In particular, malaria is a cause of concern. In those countries at the edge of its distribution, it can be difficult to distinguish between autochthonous and imported cases. However, distinguishing between the two is important because of the different allocation of resources to combat the disease that each requires. In general, observation of the various stages of parasite development in wild-caught female mosquitoes is considered evidence of autochthonous transmission. Observation of oocysts in the mosquito mid-gut testifies that mosquitoes are susceptible to infection but conclusions cannot be reached about their ability to complete the transmission cycle. Perhaps the best indication of autochthonous transmission is microscopic observation of sporozoites in mosquito salivary glands, since this detects parasites ready to be inoculated (BELER et al., 1990). Detection of circumsporozoite protein (CSP)(BURKOT, WILLIAMS & SCHNEIDER, 1984) in dry mosquito thoraxes, by Enzyme Linked Immunosorbent Assay (ELISA) is also widely used to determine transmission, especially when large numbers of mosquitoes need to be processed. Such assays provide information about the parasite species infecting the mosquito (BURKOT & WIRTZ, 1986; WIRTZ et al., 1987; BELER et al., 1990)

Improving positive and negative bias illumination stress stability in parylene passivated IGZO transistors

The impact of a parylene top-coating layer on the illumination and bias stress instabilities of indium-gallium-zinc oxide thin-film transistors (TFTs) is presented and discussed. The parylene coating substantially reduces the threshold voltage shift caused by continuous application of a gate bias and light exposure. The operational stability improves by 75%, and the light induced instability is reduced by 35%. The operational stability is quantified by fitting the threshold voltage shift with a stretched exponential model. Storage time as long as 7 months does not cause any measurable degradation on the electrical performance. It is proposed that parylene plays not only the role of an encapsulation layer but also of a defect passivation on the top semiconductor surface. It is also reported that depletion-mode TFTs are less sensitive to light induced instabilities. This is attributed to a defect neutralization process in the presence of free electrons. Published by AIP Publishing

Parylene C as a Multipurpose Material for Electronics and Microfluidics

Funding Information: This work was financed by national funds from FCT—Fundação para a Ciência e a Tecnologia, I.P., in the scope of the projects LA/P/0037/2020, UIDP/50025/2020 and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures, Nanomodelling and Nanofabrication—i3N. Furthermore, the work received funding from FCT in the scope of projects UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences—UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy—i4HB. This work also received funding from the European Community’s H2020 program under grant agreements 716510 (ERC-2016-StG TREND), 787410 (ERC-2019-AdG DIGISMART) and 952169 (SYNERGY, H2020-WIDESPREAD-2020-5, CSA), 101008701 (EMERGE, H2020-INFRAIA-2018-2020). B. J. Coelho acknowledges FCT for the attribution of grant SFRH/BD/132904/2017 and grant COVID/BD/152453/2022. Publisher Copyright: © 2023 by the authors.Poly(p-xylylene) derivatives, widely known as Parylenes, have been considerably adopted by the scientific community for several applications, ranging from simple passive coatings to active device components. Here, we explore the thermal, structural, and electrical properties of Parylene C, and further present a variety of electronic devices featuring this polymer: transistors, capacitors, and digital microfluidic (DMF) devices. We evaluate transistors produced with Parylene C as a dielectric, substrate, and encapsulation layer, either semitransparent or fully transparent. Such transistors exhibit steep transfer curves and subthreshold slopes of 0.26 V/dec, negligible gate leak currents, and fair mobilities. Furthermore, we characterize MIM (metal–insulator–metal) structures with Parylene C as a dielectric and demonstrate the functionality of the polymer deposited in single and double layers under temperature and AC signal stimuli, mimicking the DMF stimuli. Applying temperature generally leads to a decrease in the capacitance of the dielectric layer, whereas applying an AC signal leads to an increase in said capacitance for double-layered Parylene C only. By applying the two stimuli, the capacitance seems to suffer from a balanced influence of both the separated stimuli. Lastly, we demonstrate that DMF devices with double-layered Parylene C allow for faster droplet motion and enable long nucleic acid amplification reactions.publishersversionpublishe