Thermodynamics of Chaplygin gas

We clarify thermodynamics of the Chaplygin gas by introducing the integrability condition. All thermal quantities are derived as functions of either volume or temperature. Importantly, we find a new general equation of state, describing the Chaplygin gas completely. We confirm that the Chaplygin gas could show a unified picture of dark matter and energy which cools down through the universe expansion without any critical point (phase transition).Comment: 5 pages, 4 figures, version "Accepted for publication in Astrophysics & Space Science

Insulin therapy modulates mitochondrial dynamics and biogenesis, autophagy and tau protein phosphorylation in the brain of type 1 diabetic rats

AbstractThe main purpose of this study was to examine whether streptozotocin (STZ)-induced type 1 diabetes (T1D) and insulin (INS) treatment affect mitochondrial function, fission/fusion and biogenesis, autophagy and tau protein phosphorylation in cerebral cortex from diabetic rats treated or not with INS. No significant alterations were observed in mitochondrial function as well as pyruvate levels, despite the significant increase in glucose levels observed in INS-treated diabetic rats. A significant increase in DRP1 protein phosphorylated at Ser616 residue was observed in the brain cortex of STZ rats. Also an increase in NRF2 protein levels and in the number of copies of mtDNA were observed in STZ diabetic rats, these alterations being normalized by INS. A slight decrease in LC3-II levels was observed in INS-treated rats when compared to STZ diabetic animals. An increase in tau protein phosphorylation at Ser396 residue was observed in STZ diabetic rats while INS treatment partially reversed that effect. Accordingly, a modest reduction in the activation of GSK3β and a significant increase in the activity of phosphatase 2A were found in INS-treated rats when compared to STZ diabetic animals. No significant alterations were observed in caspases 9 and 3 activity and synaptophysin and PSD95 levels. Altogether our results show that mitochondrial alterations induced by T1D seem to involve compensation mechanisms since no significant changes in mitochondrial function and synaptic integrity were observed in diabetic animals. In addition, INS treatment is able to normalize the alterations induced by T1D supporting the importance of INS signaling in the brain

Avaliação hedónica da textura de pera Rocha após armazenamento sob diferentes regimes

IX Simpósio Ibérico de Maturação e Pós Colheita. Sessões PosterA tecnologia de armazenamento de pera ‘Rocha’ influencia significativamente a textura, uma das principais características de qualidade deste fruto. As alterações tecnológicas que têm vindo a ser introduzidas no armazenamento da pera ‘Rocha’ portuguesa desde 2014 estão a provocar alterações de textura que importa compreender. Este estudo teve como objetivo avaliar a aceitação da textura de pera ‘Rocha’ por parte dos consumidores. Um painel de 100 provadores não treinados avaliou peras armazenadas a -0,5 ºC em quatro regimes distintos durante 7 meses. Foram utilizadas peras tratadas com SmartFresh e armazenadas em ar (A), tratadas com SmartFresh a metade da dose e armazenadas em 3 kPa de O2 (B) e peras não tratadas armazenadas a 3 kPa (C) e a 1 kPa de O2 (D). Os provadores classificaram a textura dos frutos numa escala 15 valores. Os provadores do sexo feminino representaram 78% do total e a distribuição etária foi: 54% [18-25]; 18% [26-35]; 15% [35-45]; 8% [46-55] e 5% com > 55 anos. A textura mediana das peras das modalidades A, B e D foi 10 e as da modalidade C foi 6. A textura das peras da modalidade C foi pior classificada por todos os escalões etários. No escalão etário [46-55] houve uma aceitação pela textura das peras da modalidade B (12,5) tendo as peras C e D sido classificadas com 7 e 6, respetivamente. No escalão etário [18-25] a mediana foi de 10, 11, 10 e 6 para as modalidades A, B, C e D respetivamente. As diferenças aproximaram-se no escalão etário [26-35] com medianas de 10 para as modalidades A, B e C e 8 para a D. As peras da modalidade D foram pior classificadas pelos escalões etários mais elevados (> 55 anos) do que pelo escalão [26-35]. O regime de armazenamento teve uma influência decisiva na textura da pera Rocha que influencia a preferência do consumidor que por sua vez não está relacionada com a dureza avaliada com o penetrómetroinfo:eu-repo/semantics/publishedVersio

High glucose and diabetes increase the release of [3H]-D-aspartate in retinal cell cultures and in rat retinas

Several evidences suggest that glutamate may be involved in retinal neurodegeneration in diabetic retinopathy (DR). For that reason, we investigated whether high glucose or diabetes affect the accumulation and the release of [3H]-D-aspartate, which was used as a marker of the glutamate transmitter pool. The accumulation of [3H]-D-aspartate did not change in cultured retinal neural cells treated with high glucose (30 mM) for 7 days. However, the release of [3H]-D-aspartate, evoked by 50 mM KCl, significantly increased in retinal cells exposed to high glucose. Mannitol, which was used as an osmotic control, did not cause any significant changes in both accumulation and release of [3H]-D-aspartate. In the retinas, 1 week after the onset of diabetes, both the accumulation and release of [3H]-D-aspartate were unchanged comparing to the retinas of agematched controls. However, after 4 weeks of diabetes, the accumulation of [3H]-D-aspartate in diabetic retinas decreased and the release of [3H]-Daspartate increased, compared to age-matched control retinas. These results suggest that high glucose and diabetes increase the evoked release of D-aspartate in the retina, which may be correlated with the hypothesis of glutamate-induced retinal neurodegeneration in DR

Evaluation of FT-Raman and FTIR-ATR spectroscopy for the quality evaluation of Lavandula spp. Honey

Monofloral Lavandula spp. honey is very appreciated by consumers due to its characteristic and pleasant aroma and flavor. Given the economic importance of this type of honey, it is important to develop a rapid and non-expensive methodology that allows certifying its quality. In this context, this study aimed to compare the applicability and accuracy of FTIR-ATR and FT-Raman techniques for the quality evaluation of Lavandula spp. honey. Calibration models, with PLS regression models, were obtained for both methodologies concerning the following parameters: total acidity, reducing sugars, hidroximetilfurfural (HMF), electrical conductivity, ash, proline content, diastase activity, apparent sucrose, total flavonoids, and total phenolic contents. The calibration models had high regression coefficients, r2 (FTIR-ATR: 0.965–0.996; FT-Raman: 0.983–0.999), high ratios of performance to deviation, RPD (FTIR-ATR: 5.4–15.7; FT-Raman: 7.6–53.7), and low root mean square errors (RMSEs; FTIR-ATR: 0.005–3.0; FT-Raman: 0.004–1.02). These results corroborate the potentiality of FTIR-ATR and FT-Raman for quality evaluation and evaluation of the chemical properties of Lavandula spp. honey even though FT-Raman technique provided more accurate models.Centro de Estudos Florestais is a research unit funded by FCT (UIDB/00239/2020). Financial support is acknowledged to CIMO Research Centre, a research unit funded by FCT (project Ref.a UIDB/00690/2020) and supported by Polytechnic Institute of Bragança. Financial support for publication is acknowledged to CERNAS Research Centre, a research unit funded by FCT (project Ref.a UIDB/00681/2020) and supported by Polytechnic Institute of Viseu. The Open Access Article Processing Charges was funded by CERNAS Project (project Ref.a UIDB/00681/2020). This research was funded by the Forest Research Centre, a research unit funded by Fundação para a Ciência e a Tecnologia I. P. (FCT), Portugal (UIDB/ 00239/2020), and CIMO Research Centre, a research unit funded by FCT (FCT), Portugal (UIDB/00690/2020) and supported by Polytechnic Institute of Bragança.info:eu-repo/semantics/publishedVersio

The Action of Polyphenols in Diabetes Mellitus and Alzheimer's Disease: A Common Agent for Overlapping Pathologies

Diabetes Mellitus (DM) and Alzheimer's disease (AD) are two prevalent diseases in modern societies, which are caused mainly by current lifestyle, aging and genetic alterations. It has already been demonstrated that these two diseases are associated, since individuals suffering from DM are prone to develop AD. Conversely, it is also known that individuals with AD are more susceptible to DM, namely type 2 diabetes (T2DM). Therefore, these two pathologies, although completely different in terms of symptomatology, end up sharing several mechanisms at the molecular level, with the most obvious being the increase of oxidative stress and inflammation. Polyphenols are natural compounds widely spread in fruits and vegetables whose dietary intake has been considered inversely proportional to the incidence of DM and AD. So, it is believed that this group of phytochemicals may have preventive and therapeutic potential, not only by reducing the risk and delaying the development of these pathologies, but also by improving brain's metabolic profile and cognitive function. The aim of this review is to understand the extent to which DM and AD are related pathologies, the degree of similarity and the relationship between them, to detail the molecular mechanisms by which polyphenols may exert a protective effect, such as antioxidant and anti-inflammatory effects, and highlight possible advantages of their use as common preventive and therapeutic alternatives.info:eu-repo/semantics/publishedVersio

Amplification of evanescent waves in a lossy left-handed material slab

We carry out finite-difference time-domain (FDTD) simulations, with a specially-designed boundary condition, on pure evanescent waves interacting with a lossy left-handed material (LHM) slab. Our results provide the first full-wave numerical evidence for the amplification of evanescent waves inside a LHM slab of finite absorption. The amplification is due to the interactions between the evanescent waves and the coupled surface polaritons at the two surfaces of the LHM slab and the physical process can be described by a simple model.Comment: 4 pages, 2 figure

Collapse dynamics of trapped Bose-Einstein condensates

We analyze the implosion and subsequent explosion of a trapped condensate after the scattering length is switched to a negative value. Our results compare very well qualitatively and fairly well quantitatively with the results of recent experiments at JILA.Comment: 4 pages, 3 figure

Evolução do perfil sensorial de textura de pera Rocha durante o período de armazenamento

IX Simpósio Ibérico de Maturação e Pós Colheita. Sessão Pós colheita de maçã e peraA textura é uma das principais características de qualidade da pera ‘Rocha’. Esta característica multidimensional tem uma complexidade mecânica e sensorial que não pode ser reduzida à simples avaliação da dureza. Este estudo teve por objetivo descrever o perfil sensorial da textura de pera ‘Rocha’ e as suas alterações durante o amadurecimento e ao longo do período de armazenamento. Frutos de pera ‘Rocha’ foram armazenados em quatro regimes distintos e analisados após 3, 5 e 7 meses de armazenamento a -0,5 ºC, em dois momentos após a retirada das câmaras. Foi efetuada a análise do perfil de textura sensorialmente com um painel treinado de 11 provadores de acordo com a norma ISO 11036:1994. O perfil de textura da pera ‘Rocha’ após 3 meses de armazenamento apresenta elevada dureza, fracturabilidade, coesividade, gomosidade e mastigabilidade, uma suculência intermédia, e reduzida adesividade e elasticidade. Com o amadurecimento da pera diminuiu a dureza, a fracturabilidade, a coesividade, a gomosidade e a mastigabilidade e aumentou a suculência e a adesividade. As variações do perfil sensorial de textura durante o amadurecimento pós-armazenamento foram equivalentes em frutos armazenados no ar ou em atmosfera controlada com 3 kPa de O2, mas distintos em peras tratadas com 1-metilciclopropeno (1-MCP). Frutos tratados apresentaram, nos diferentes períodos de armazenamento, valores de dureza, fracturabilidade, gomosidade e mastigabilidade superiores, enquanto a adesividade e coesividade foram inferiores aos dos frutos não-tratados. No período pós-armazenamento, frutos tratados com 1-MCP apresentaram dureza e fracturabilidade superior mas a mastigabilidade foi o atributo mais afetado pelo tratamento. Em períodos de armazenamento mais prolongados esta distinção é ainda mais notória pelos elevados níveis de mastigabilidade registados nos frutos tratadosinfo:eu-repo/semantics/publishedVersio

Exact time-dependent correlation functions for the symmetric exclusion process with open boundary

As a simple model for single-file diffusion of hard core particles we investigate the one-dimensional symmetric exclusion process. We consider an open semi-infinite system where one end is coupled to an external reservoir of constant density $\rho^\ast$ and which initially is in an non-equilibrium state with bulk density $\rho_0$. We calculate the exact time-dependent two-point density correlation function $C_{k,l}(t)\equiv -$ and the mean and variance of the integrated average net flux of particles $N(t)-N(0)$ that have entered (or left) the system up to time $t$. We find that the boundary region of the semi-infinite relaxing system is in a state similar to the bulk state of a finite stationary system driven by a boundary gradient. The symmetric exclusion model provides a rare example where such behavior can be proved rigorously on the level of equal-time two-point correlation functions. Some implications for the relaxational dynamics of entangled polymers and for single-file diffusion in colloidal systems are discussed.Comment: 11 pages, uses REVTEX, 2 figures. Minor typos corrected and reference 17 adde