The complex channel networks of bone structure

Bone structure in mammals involves a complex network of channels (Havers and Volkmann channels) required to nourish the bone marrow cells. This work describes how three-dimensional reconstructions of such systems can be obtained and represented in terms of complex networks. Three important findings are reported: (i) the fact that the channel branching density resembles a power law implies the existence of distribution hubs; (ii) the conditional node degree density indicates a clear tendency of connection between nodes with degrees 2 and 4; and (iii) the application of the recently introduced concept of hierarchical clustering coefficient allows the identification of typical scales of channel redistribution. A series of important biological insights is drawn and discussedComment: 3 pages, 1 figure, The following article has been submitted to Applied Physics Letters. If it is published, it will be found online at http://apl.aip.org

Color space distortions in patients with type 2 diabetes mellitus

Color vision impairment was examined in patients with type 2 diabetes mellitus (DM2) without retinopathy. We assessed the type and degree of distortions of individual color spaces. DM2 patients (n = 32), and age-matched controls (n = 20)were tested using the Farnsworth D-15 and the Lanthony D-15d tests. In addition, subsets of caps from both tests were employed in a triadic procedure (Bimler & Kirkland, 2004). Matrices of inter-cap subjective dissimilarities were estimated from each subject’s “odd-one-out” choices, and processed using non-metric multidimensional scaling. Two-dimensional color spaces, individual and group (DM2 patients; controls), were reconstructed, with the axes interpreted as the R0G and B0Y perceptual opponent systems. Compared to controls, patient results were not significant for the D-15 and D-15d. In contrast, in the triadic procedure the residual distances were significantly different compared to controls: right eye, P 0.021, and left eye, P 0.022. Color space configurations for the DM2 patients were compressed along the B0Y and R0G dimensions. The present findings agree with earlier studies demonstrating diffuse losses in early stages of DM2. The proposed method of testing uses color spaces to represent discrimination and provides more differentiated quantitative diagnosis, which may be interpreted as the perceptual color system affected. In addition, it enables the detection of very mild color vision impairment that is not captured by the D-15d test. Along with fundoscopy, individual color spaces may serve for monitoring early functional changes and thereby to support a treatment strategy

Noncommutative Thermofield Dynamics

The real-time operator formalism for thermal quantum field theories, thermofield dynamics, is formulated in terms of a path-integral approach in non-commutative spaces. As an application, the two-point function for a thermal non-commutative $\lambda \phi^4$ theory is derived at the one-loop level. The effect of temperature and the non-commutative parameter, competing with one another, is analyzed.Comment: 13 pages; to be published in IJMP-A

The cholesterol 24-hydroxylase activates autophagy and decreases mutant huntingtin build-up in a neuroblastoma culture model of Huntington’s disease

Objective Compromised brain cholesterol turnover and altered regulation of brain cholesterol metabolism have been allied with some neurodegenerative diseases, including Huntington’s disease (HD). Following our previous studies in HD, in this study we aim to investigate in vitro in a neuroblastoma cellular model of HD, the effect of CYP46A1 overexpression, an essential enzyme in cholesterol metabolism, on huntingtin aggregation and levels. Results We found that CYP46A1 reduces the quantity and size of mutant huntingtin aggregates in cells, as well as the levels of mutant huntingtin protein. Additionally, our results suggest that the observed beneficial effects of CYP46A1 in HD cells are linked to the activation of autophagy. Taken together, our results further demonstrate that CYP46A1 is a pertinent target to counteract HD progression.This work was supported by Brainvectis and E.rare: E-Rare Joint Transnational Call for Proposals 2017 “Transnational Research Projects for Innovative Therapeutic Approaches for Rare Diseases”. CN laboratory is supported by the French Muscular Dystrophy Association (AFM-Téléthon), the Ataxia UK, and the Fundação para a Ciência e Tecnologia (project ALG-01-0145-FEDER-29480 “SeGrPolyQ”). AM is supported by a Ph.D. fellowship from FCT (SFRH/BD/133192/2017)info:eu-repo/semantics/publishedVersio

Influence of Insulin-like Growth Factor I (IGF-I) on the survival and the in vitro development of caprine preantral follicles

The aim of this study was to investigate the effects of the insulin-like growth factor -I (IGF-I) on survival, activation (transition from primordial to primary follicles) and growth of caprine preantral follicles cultured in vitro. Fragments of ovarian cortex were cultured for one and seven days in the absence or presence of IGF-I (0, 50 and 100ng/ml). The non-cultured and cultured tissues were processed and analyzed by histology and transmission electron microscopy. The culture for one day in a medium with 100ng/ml of IGF-I showed 86.7% of morphologically normal follicles. These results were similar (P>0.05) to the percentage of normal follicles found in the control (96.7%). It was also found that this medium increased the percentage of follicular activation (developing follicles) with one day of culture. The oocyte and follicular diameters remained similar to the control by culturing for one day in a medium containing 100ng/ml of IGF-I. The ultrastructural analysis did not confirm the integrity of the follicular fragments in a medium containing IGF-I (100ng/ml) after one and seven days of culture. In conclusion, this study demonstrated that the addition of 100 ng/ml of IGF-I in the culture medium enables the development of preantral follicles of goats with one day of culture. However, it is not sufficient to maintain the follicular integrity and the follicular survival rate after seven days of culture.O objetivo do presente estudo foi investigar os efeitos do fator de crescimento semelhante a insulina-I (IGF-I) na sobrevivência, ativação (transição de folículos primordiais para primários) e crescimento de folículos pré-antrais caprinos cultivados in vitro. Fragmentos de córtex ovariano foram cultivados por um e sete dias na ausência ou presença de IGF-I (0, 50 e 100ng/mL). Os tecidos não cultivados e cultivados foram processados e analisados por histologia e microscopia eletrônica de transmissão. O cultivo por um dia em meio com 100ng/mL de IGF-I apresentou 86,7% de folículos morfologicamente normais. Estes resultados foram semelhantes (P>0,05) ao percentual de folículos normais encontrados no controle (96,7%). Verificou-se ainda que este meio aumentou o percentual de ativação folicular (folículos em desenvolvimento) com um dia de cultivo. Os diâmetros ovocitário e folicular mantiveram-se semelhantes ao controle ao cultivar por um dia em meio contendo 100ng/mL de IGF-I. As análises ultraestruturais não confirmaram a integridade folicular dos fragmentos em meio contendo IGF-I (100 ng/mL) após um e sete dias de cultivo. Em conclusão, esse estudo demonstrou que a adição de 100 ng/mL de IGF-I no meio de cultivo ativa o desenvolvimento de folículos pré-antrais de caprinos com um dia de cultivo. Entretanto, não é suficiente para manter a integridade folicular e a taxa de sobrevivência folicular após sete dias de cultivo

Analysis of Stationary- and Synchronous-Reference Frames for Three-Phase Three-Wire Grid-Connected Converter AC Current Regulators

The current state of the art shows that unbalance and distortion on the voltage waveforms at the terminals of a grid-connected inverter disturb its output currents. This paper compares AC linear current regulators for three-phase three-wire voltage source converters with three different reference frames, namely: (1) natural (abc), (2) orthogonal stationary (αβ), and (3) orthogonal synchronous (dq). The quantitative comparison analysis is based on mathematical models of grid disturbances using the impedance-based analysis, the computational effort assessment, as well as the steady-state and transient performance evaluation based on experimental results. The control scheme devised in the dq-frame has the highest computational effort and inferior performance under negative-sequence voltage disturbances, whereas it shows superior performance under positive-sequence voltages among the reference frames evaluated. In contrast, the stationary natural frame abc has the lowest computational effort due to its straightforward implementation, with similar results in terms of steady-state and transient behavior. The αβ-frame is an intermediate solution in terms of computational cost.This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001.© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed

Evaluation of two ultrasonic systems for analysis of porosity in ceramic

The Ultrasound Laboratory of the Nuclear Engineering Institute (LABUS / IEN) has developed an ultrasonic technique to measure porosity in nuclear fuel pellets (UO2). By difficulties related to the handling of UO2 pellets, Alumina (Al2O3) pellets have been used in preliminary tests, until a methodology for tests with pellets of UO2 could be defined. In a previous work, in which a contact ultrasonic technique was used, good results were obtained to measure the porosity of Alumina pellets. In the current studies, it was found that the frequency spectrum of an ultrasonic pulse is very sensitive to the porosity of the medium in which it propagates. In order to define the most appropriate experimental apparatus for using immersion technique in future tests, two ultrasonic systems, available in LABUS, which permit to work with the ultrasonic pulse in the frequency domain were evaluated . One system was the Explorer II (Matec INSTRUMENTS) and the other the ultrasonic pulse generator Epoch 4 Plus (Panametrics) coupled with an oscilloscope TDS 3032B (Tektronix). For this evaluation, several frequency spectra were obtained with the two equipment, by the passage of the ultrasonic wave in the same pellet of Alumina. This procedure was performed on four different days, on each day 12 ultrasonic signals were acquired, one signal every 10 minutes, with each apparatus. The results were compared and analyzed as regard the repeatability of the frequency spectra obtained