Controlled delivery achieved with bi-layer matrix devices produced by co-injection moulding

The aim of this study was to design new soy protein-based bi-layered co-injection moulded matrix systems aimed to achieve controlled drug delivery. The devices consisted of a drug-free outer layer (skin) and a drug-containing core. The systems overcame the inherent disadvantage of non-linear release associated with diffusion-controlled single-layer matrix devices by providing additional releasing area with time to compensate for the decreasing release rate. As expected, the bi-layer devices presented a significant decrease in drug release rate when compared with a correspondent single layer matrix system. The skin thickness and the degree of crosslinking of the core appeared to be very important tools to tailor the release patterns. Furthermore, due to the amphoteric nature of the soy protein, the developed devices evidenced a pH-dependent behaviour. The mechanisms of drug release were also elucidated at two different pH values: i) pH 5.0, near the isoelectric point of soy (low matrix solubility); and ii) pH 7.4, physiological pH (high matrix solubility). Consequently, changing the release medium from pH 5.0 to pH 7.4 after two hours, led to an abrupt increase in drug release and the devices presented a typical controlled drug delivery profile: slow release/fast release. These evidences may provide for the development of individual systems with different release onsets that in combination may exhibit drug releases at predetermined times in a pre-programmed way. Another possibility is the production of three-layer devices presenting bimodal release profiles (fast release/slow release/fast release) by similar technologies.Portuguese Foundation for Science and Technology (FCT), Ministry of Science and Technology, Portugal

The Little Hierarchy in Universal Extra Dimensions

In the standard model in universal extra dimensions (UED) the mass of the Higgs field is driven to the cutoff of the higher-dimensional theory. This re-introduces a small hierarchy since the compactification scale 1/R should not be smaller than the weak scale. In this paper we study possible solutions to this problem by considering five-dimensional theories where the Higgs field potential vanishes at tree level due to a global symmetry. We consider two avenues: a Little Higgs model and a Twin Higgs model. An obstacle for the embedding of these four-dimensional models in five dimensions is that their logarithmic sensitivity to the cutoff will result in linear divergences in the higher dimensional theory. We show that, despite the increased cutoff sensitivity of higher dimensional theories, it is possible to control the Higgs mass in these two scenarios. For the Little Higgs model studied, the phenomenology will be significantly different from the case of the standard model in UED. This is due to the fact that the compactification scale approximately coincides with the scale where the masses of the new states appear. For the case of the Twin Higgs model, the compactification scale may be considerably lower than the scale where the new states appear. If it is as low as allowed by current limits, it would be possible to experimentally observe the standard model Kaluza-Klein states as well as a new heavy quark. On the other hand, if the compactification scale is higher, then the phenomenology at colliders would coincide with the one for the standard model in UED.Comment: 25 pages, 2 figure

Effect of processing conditions on electromagnetic shielding and electrical resistivity of injection-molded polybutylene terephthalate compounds

This research introduces an analysis of the anisotropic electrical resistivity (ER) and its relation to the electromagnetic shielding effectiveness (EMSE) for two injection-molded carbon-fiber-reinforced polybutylene terephthalates (PBTs). The properties were measured for 2-mm thick injection moldings considering the effect of melt temperature, injection velocity, and flow distance. The results for one compound showed an EMSE in the range of 30–40 dB, while EMSE for a compound with lower filler content is in the range of 45–75 dB. A combination of higher temperature and higher velocity leads to an increase of EMSE for both compounds in the range of 3%–8.5%. However, the increase in flow path reduced the EMSE for both compounds up to 10%. A novel experimental apparatus was used to measure the anisotropic ER in the three directions, that is, parallel, perpendicular, and transversal to flow. It is evident that injection molding induced high anisotropy for both compound specimens, and, depending on the processing conditions, produced similar longitudinal resistivity (0.2–4 Ω.cm) but higher transversal resistivity (8–22 Ω.cm). ER properties were compared with EMSE, evidencing an inverse relation as expected. Furthermore, it was found that the longitudinal resistivity is the main contributor to the specimens shielding.The authors would like to acknowledge all the associates from University of Minho, Centre for Innovation in Polymer Engineering (PIEP and Bosch Car Multimedia who had an active part in the development of this research and acknowledge that this project, INNOVCAR, was supported by the European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Program (COMPETE 2020) [Project no 002797; Funding Reference: POCI-01-0247-FEDER-002797]

Novel auxetic thermoset and thermoplastic composites for energy absorption

Auxetic materials are characterized as materials with negative Poisson’s ratio (NPR), i.e. stretching of these materials in longitudinal direction results in widening in the transverse direction. This counterintuitive behaviour provides higher energy absorption capacity and damage resistance. Auxetic composites can be made from conventional materials, using the laminated angle-ply method, in which the layers are stacked in a special sequence resulting in NPR. Accordingly, the use of carbon fibers as reinforcement is more appropriate than kevlar or glass fibers as they combine exceptional mechanical properties and low weight. Indeed, there are several carbon fibers and matrices that make them suitable for a range of end-uses. This research work focuses on investigating the mechanical properties of composites reinforced with unidirectional carbon fibers. For this purpose, the effects of fiber orientations and the influence of resin type on the mechanical properties and Poisson’s ratio have been investigated as regards to the tensile and impact behaviours. Carbon fiber stacked at different angles reinforcing thermoset and thermoplastic polymers were studied.FCT, projeto “Development of Auxetic Fibrous Composite for Personal Protection, ref. POCI-01-0145-FEDER-016893 e PTDC/CTM-POL/5814/201

Quasi static mechanical study of vacuum bag infused bouligand inspired composites

Three novel Bouligand inspired composites were produced by vacuum bag infusion manufacturing process and their quasi-static mechanical performance were compared to a conventional aircraft laminate. A morphologic/physical study was first conducted for all configurations and their mechanical response under tensile, three-point bending (3-PB) and interlaminar shear strength (ILSS) tests were then evaluated and discussed. No significant number of voids were detected into laminates, however, a rough and poor defined interlaminar region was observed in both Bouligand-like configurations. Under quasi-static mechanical solicitations, and when compared to reference layup, bioinspired configurations have shown similar and 18% higher tensile and flexural modulus. However, the progressive and translaminar failure mode, typically observed in these configurations, led to a lower load bearing capability. Despite presented similar interlaminar resistance than reference, finite element models built have revealed a good correlation between cross-section stress field and failure mode observed experimentally.Fundação para a Ciência e Tecnologia (FCT), Projetos UIDB/05256/2020, UIDP/05256/2020 e MITP-TB/PFM/0005/201

Characterization of auxetic and mechanical behaviours of auxetic composites developed using star knitted structures

This work evaluates the auxetic behaviour of composite materials produced from weft-knitted fabrics made from high-tenacity para-aramid (p-AR) and polyamide 6.6 (PA) fibres, which have proven to present negative Poisson’s ratios (NPR). Composites were produced by reinforcing an epoxy resin with those developed fabrics and the degree to which they were able to preserve the previous auxetic behaviour of the fibrous reinforcements investigated in order to obtain a new type of auxetic materials, reinforced with re-entrant star designed fabrics, that could present higher mechanical performance due to its NPR behaviour.This work was funded by the Operational Program of Competitiveness and Internationalization (POCI) with financial support from the European Regional Development Fund (FEDER) and Portuguese Foundation for Science and Technology (FCT), under the project “Development of Auxetic Fibrous Composite for Personal Protection” (ref. POCI-01-0145-FEDER-016893 and PTDC/CTM-POL/5814/2014).info:eu-repo/semantics/publishedVersio

Physiological and biochemical responses of Eucalyptus seedlings to hypoxia

International audienceAbstractKey messageHypoxia promoted distinct changes in the levels of hormones, amino acids and organic acids in the roots and shoots of a seedling from 2Eucalyptusclones. These results indicate that modulation of hormone production, as well as specific chemical constituents associated with primary metabolism, contributes to the regulation of growth ofEucalyptusseedlings under hypoxic conditions.ContextAlthough floods in areas under Eucalyptus cultivation in Brazil negatively affect plant growth, chemical markers and/or indicators of hypoxia contributes to the regulation.sAimsThis study aimed to evaluate the hormonal and metabolic alterations induced by hypoxia on seedling growth.MethodsSeedlings of Eucalyptus urograndis clones VCC 975 and 1004 were grown in liquid solution and submitted to bubbling with air or with nitrogen. Levels of indol-3-acetic acid (IAA), abscisic acid (ABA), ethylene, 1-aminocyclopropane-1-carboxylic acid (ACC), primary metabolite profile and photosynthetic parameters were evaluated after fourteen days.ResultsHypoxia did not affect shoot dry mass of the seedlings. However, it decreased stomatal conductance and photosynthetic CO2 assimilation rate, and increased levels of ABA in the shoot. Hypoxia greatly reduced the dry mass and volume of roots, concomitantly with higher ACC and ethylene production. Moreover, hypoxia promoted distinct changes in IAA levels, and in amino acid and organic acid metabolism in roots and shoots.ConclusionThe biosynthesis of ABA, ethylene and IAA and its quantity in root tissues indicates the regulation of metabolism in response to hypoxia in Eucalyptus clones

Unstable fields in Kerr spacetimes

We show that both the interior region $r<M-\sqrt{M^2-a^2}$ of a Kerr black hole and the $a^2>M^2$ Kerr naked singularity admit unstable solutions of the Teukolsky equation for any value of the spin weight. For every harmonic number there is at least one axially symmetric mode that grows exponentially in time and decays properly in the radial directions. These can be used as Debye potentials to generate solutions for the scalar, Weyl spinor, Maxwell and linearized gravity field equations on these backgrounds, satisfying appropriate spatial boundary conditions and growing exponentially in time, as shown in detail for the Maxwell case. It is suggested that the existence of the unstable modes is related to the so called "time machine" region, where the axial Killing vector field is time-like, and the Teukolsky equation, restricted to axially symmetric fields, changes its character from hyperbolic to elliptic

Neuromuscular facilitation in proprioceptive juvenile dermatomyositis: a case report

Introd ução: Dermatomiosite Juvenil (DMJ) é uma doença muscular inflamatória de etiologia desconhecida, auto-imune, e que se manifesta nos pequenos vasos sanguíneos dos músculos e pele. A incidência varia entre 0,8 e 4,1 por milhão de crianças nascidas por ano, com prevalência do sexo feminino. São cinco os critérios de diagnóstico: fraqueza simétrica proximal progressiva, enzimas musculares elevadas, anormalidades no eletromiograma, padrão inflamatório na amostra da biópsia muscular, e associação com distúrbios cutâneos. OBJETIVO: Relatar a Facilitação Neuromuscular Proprioceptiva (FNP) em um caso de DMJ. MÉTODO: Foi avaliada uma paciente do sexo feminino, nove anos de idade, com quadro de DMJ e com sintomas de: fraqueza muscular, dificuldade em atividades de vida diária e quedas freqüentes, que se encontra em acompanhamento médico ambulatorial no Hospital Foram realizadas três avaliações, antes (AV-1), durante (AV-2) e após (AV-3) a intervenção fisioterapêutica. Após a primeira avaliação, foi aplicado um tratamento com 24 sessões, com duração de uma hora cada sessão, durante 12 semanas, que constou de Facilitação Neuromuscular Proprioceptiva (FNP) com técnicas de estímulo de estiramento e reversões lentas nas diagonais primitiva e funcional, bem como alongamentos associados. RESULTADOS: Aumento da força muscular em membros inferiores, diminuição de contraturas, ganho de amplitude de movimento articular e melhor qualidade de vida para a paciente. CONCLUSÃO: Em vista dos resultados expostos, a utilização da FNP foi satisfatória, e estudos longitudinais são necessários para que se comprove a eficácia a longo prazo.Introduction : Juvenile dermatomyositis (DM) is an inflammatory muscle disease of unknown etiology, autoimmune disorder, which manifests itself in small blood vessels of the muscles and skin. The incidence varies between 0.8 and 4.1 per million children born each year with a prevalence of females. Five criteria are considered for diagnosis: progressive proximal symmetrical weakness, elevated muscle enzymes, abnormal electromyogram and inflammatory pattern in the muscle biopsy sample, and association with cutaneous disorders. OBJECTIVE: To report the Neuromuscular Facilitation Proprioceptive (PFN) procedure in a case of juvenile DM. METHODS: We evaluated a female patient, nine years old, with part of JDM, who manifested: muscle weakness, difficulty in daily activities and frequent falls. She attended the out patient service at our Hospital Three evaluations were performed before (AV-1), during (AV-2) and after (AV-3) to physiotherapy intervention. After the first evaluation, a treatment was applied in 24 sessions over 12 weeks, lasting an hour each, which consisted of Neuromuscular Facilitation proprioceptive (FNP) with stimulating techniques of stretching and slow reversals in diagonal primitive and functional as well as associated stretching. RESULTS: Increased muscle strength in lower limbs, reduction of contractures, gain range of motion and better quality of life for the patient. CONCLUSION: Considering the above results, longitudinal studies are required to prove efficacy in long-term

Apolipoprotein E polymorphism influences orthotopic liver transplantation outcomes in patients with hepatitis C virus-induced liver cirrhosis

BACKGROUND: Hepatitis C virus (HCV) infection is responsible for a chronic liver inflammation, which may cause end-stage liver disease and hepatocellular carcinoma. Apolipoprotein E (protein: ApoE, gene: APOE), a key player in cholesterol metabolism, is mainly synthesized in the liver and APOE polymorphisms may influence HCV-induced liver damage. AIM: To determine whether APOE alleles affect outcomes in HCV-infected patients with liver cirrhosis following orthotopic liver transplantation (OLT). METHODS: This was a cohort study in which 179 patients, both genders and aged 34-70 years, were included before or after (up to 10 years follow-up) OLT. Liver injury severity was assessed using different criteria, including METAVIR and models for end-stage liver disease. APOE polymorphisms were analyzed by quantitative real-time polymerase chain reaction. RESULTS: The APOE3 allele was the most common (67.3%). In inflammation severity of biopsies from 89 OLT explants and 2 patients in pre-transplant, the degree of severe inflammation (A3F4, 0.0%) was significantly less frequent than in patients with minimal and moderate degree of inflammation (≤ A2F4, 16.2%) P = 0.048, in patients carrying the APOE4 allele when compared to non-APOE4. In addition, a significant difference was also found (≤ A2F4, 64.4% vs A3F4, 0.0%; P = 0.043) and (A1F4, 57.4% vs A3F4, 0.0%; P = 0.024) in APOE4 patients when compared to APOE3 carriers. The fibrosis degree of the liver graft in 8 of 91 patients and the lack of the E4 allele was associated with more moderate fibrosis (F2) (P = 0.006). CONCLUSION: Our results suggest that the E4 allele protects against progression of liver fibrosis and degree of inflammation in HCV-infected patients