1,148 research outputs found

    ANALISYS OF THERMAL EFFICIENCY OF A MODIFIED SOLAR COLLECTOR TYPE EVACUATED TUBE

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    The need of renewable energy sources due to climate change and thus the search for clean energy sources, justify the growing investment on new types of solar collectors. The research has contributed to this expansion in the scope of solar concentrator collectors, with the efficiency as the main goal. Many works have been developed in order to optimize the thermal stratification of the fluid inside the tubes and heat reservoirs, as well as mathematical modeling considering the problem as transient heat flow as boundary condition. In this work is studied experimentally, the heating of the water by solar collector modified from the conventional evacuated tube, focusing on efficiency. With the help of CFD software, a theoretical analysis is done to visualize the phenomenon, assuming the same boundary conditions and geometric experimental problem. An important approach concerns the physical separation of the flows of both cold and hot water inside the evacuated tube. The system performance was analyzed using experimental tests performed outdoors with sunlight

    Assembly of the Auditory Circuitry by a Hox Genetic Network in the Mouse Brainstem

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    Rhombomeres (r) contribute to brainstem auditory nuclei during development. Hox genes are determinants of rhombomere-derived fate and neuronal connectivity. Little is known about the contribution of individual rhombomeres and their associated Hox codes to auditory sensorimotor circuitry. Here, we show that r4 contributes to functionally linked sensory and motor components, including the ventral nucleus of lateral lemniscus, posterior ventral cochlear nuclei (VCN), and motor olivocochlear neurons. Assembly of the r4-derived auditory components is involved in sound perception and depends on regulatory interactions between Hoxb1 and Hoxb2. Indeed, in Hoxb1 and Hoxb2 mutant mice the transmission of low-level auditory stimuli is lost, resulting in hearing impairments. On the other hand, Hoxa2 regulates the Rig1 axon guidance receptor and controls contralateral projections from the anterior VCN to the medial nucleus of the trapezoid body, a circuit involved in sound localization. Thus, individual rhombomeres and their associated Hox codes control the assembly of distinct functionally segregated sub-circuits in the developing auditory brainstem

    Ofd1 Controls Dorso-Ventral Patterning and Axoneme Elongation during Embryonic Brain Development.

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    Oral-facial-digital type I syndrome (OFDI) is a human X-linked dominant-male-lethal developmental disorder caused by mutations in the OFD1 gene. Similar to other inherited disorders associated to ciliary dysfunction OFD type I patients display neurological abnormalities. We characterized the neuronal phenotype that results from Ofd1 inactivation in early phases of mouse embryonic development and at post-natal stages. We determined that Ofd1 plays a crucial role in forebrain development, and in particular, in the control of dorso-ventral patterning and early corticogenesis. We observed abnormal activation of Sonic hedgehog (Shh), a major pathway modulating brain development. Ultrastructural studies demonstrated that early Ofd1 inactivation results in the absence of ciliary axonemes despite the presence of mature basal bodies that are correctly orientated and docked. Ofd1 inducible-mediated inactivation at birth does not affect ciliogenesis in the cortex, suggesting a developmental stage-dependent role for a basal body protein in ciliogenesis. Moreover, we showed defects in cytoskeletal organization and apical-basal polarity in Ofd1 mutant embryos, most likely due to lack of ciliary axonemes. Thus, the present study identifies Ofd1 as a developmental disease gene that is critical for forebrain development and ciliogenesis in embryonic life, and indicates that Ofd1 functions after docking and before elaboration of the axoneme in vivo

    Human-animal relationship dysfunction: A case study of animal hoarding in italy

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    “Animal hoarding” or “compulsive hoarding of animals” is a psychiatric disease, which has important social implications and a profound influence on animal welfare. To date, this phenomenon has been little investigated and largely unexplored. The present study aims to systematically describe a case of animal hoarding, which remains unresolved. The report refers to a case of a woman suffering from animal hoarding that emerged in 2005. From March 2014 to December 2019, 450 animals were seized over nine different occasions. This disease had significant implications on the welfare of the animals collected, which lived in poor housing and hygiene conditions that frequently led to their death. Since animal hoarding cases involve sanitary, legal, and veterinary aspects, we believe that a multidisciplinary approach is necessary in order to prevent a recurrence and a new accumulation of animals. A holistic approach should be taken according to the One Health principle that involves different stakeholders at every level in order to adopt an efficient solution

    ANALYSIS OF LAMINAR FORCED CONVECTION INSIDE A SQUARE VENTILATED CAVITY USING THE OPENFOAM®

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    Laminar forced convection inside a square cavity with inlet and outlet ports was numerically analyzed. The positions of the inlet and outlet ports were fixed and the ports sizes were equal 25% of the side wall. The influence of the Reynolds and Prandtl numbers on the flow and temperature fields inside the cavity was verified for nine cases, with Re = 50, 100 and 500 and Pr = 0.7, 3 and 5. The heat transfer process in the cavity was analyzed from obtained values for the average Nusselt number and the local Nusselt number on the walls. The open source computer package OpenFOAM® was used for simulations considering a two-dimensional flow. For all tested Prandtl numbers, there is a growth in the rotating vortex regions as Reynolds number is increases. The temperature fields are directly related to the presence of the rotating vortices and the temperature gradient is more noticeable at the interface sections of the throughflow stream with the neighboring vortices and the next to the walls for greater Reynolds and Prandtl numbers. It was verified that the local Nusselt number on the walls varies radically with minimum and maximum points and it is dependent on the flow and temperature fields adjacent to the respective wall. The results for average Nusselt number per wall indicated that the bottom wall is the most susceptible to variations in its average Nusselt number and that the top wall present higher values of this parameter for all tested cases. Finally, the average Nusselt number was increased with increasing the Reynolds and Prandtl numbers indicating the enhanced thermal exchange

    Redescription of Cardiosporidium cionae (Van Gaver and Stephan, 1907) (Apicomplexa: Piroplasmida), a plasmodial parassite of ascidian haemocytes

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    Cardiosporidium cionae (Apicomplexa), from the ascidian Ciona intestinalis L., is redescribed with novel ultrastructural, phylogenetic and prevalence data. Ultrastructural analysis of specimens of C. intestinalis collected from the Gulf of Naples showed sporonts and plasmodia of C. cionae within the host pericardial body. Several merogonic stages and free merozoites were found in the pericardial body, together with sexual stages. All stages showed typical apicomplexan cell organelles, i.e. apicoplasts, rhoptries and subpellicular microtubules. Merogonic stages of C. cionae were also produced inside haemocytes. A fragment of the rSSU gene of C. cionae was amplified by PCR using DNA extracted from the pericardial bodies. The amplified product showed closest affinity with other apicomplexan representatives and a 66 bp unique insertion, specific for C. cionae, at position 1644. Neighbour-joining phylogenetic analysis placed C. cionae in a clade with other piroplasm genera, including Cytauxzoon, Babesia and Theileria spp. The parasite was found in different populations of C. intestinalis with highest prevalence in October–November. Ultrastructural and DNA data showed that the organism, described in 1907 from the same host but not illustrated in detail, is a member of a novel marine apicomplexan radiation of tunicate parasites

    VALUTAZIONE DEL CALCIO INTRACELLULARE IN PIASTINE DI CANI SANI ED AFFETTI DA LEISHMANIOSI

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    Le piastrine rappresentano gli elementi cellulari fondamentali per il processo di regolazione dell’emostasi. La loro interazione con l’endotelio vasale riveste un ruolo fondamentale sia nella fisiologia che nella fisiopatologia della coagulazione. fisiologicamente, infatti, le piastrine hanno la capacità di aderire alla parete del vaso solo dopo attivazione da parte dell’endotelio vasale. In condizioni patologiche, come quelle causate dalla rottura di una placca aterosclerotica, le piastrine aderiscono all’endotelio, si attivano e reclutano numerose altre piastrine per la formazione del tappo piastrinico. In medicina veterinaria, diversamente dalla medicina umana, la conoscenza dei meccanismi fisiologici specifici alla base di tali processi è piuttosto scarsa. Le piastrine subiscono fenomeni di attivazione, fra i quali è possibile menzionare, lo shape change, l’attivazione del recettore per il fibrinogeno che causa l’aggregazione delle piastrine, il rilascio del contenuto dei granuli e la produzione di trombossano A2 (Gachet C. et al., 1996, Mills D.C.B., 1996). Tali fenomeni sono mediati da modificazioni del calcio intracellulare che origina dal rilascio di calcio dagli store intracellulari e dall’entrata di calcio dal mezzo extracellulare (Rink T.J. et al., 1985, Rink T.J. et al., 1990). D’altro canto però, sono note numerose patologie nel cane, tra cui forme di Leishmaniosi eo Ehrlichiosi, che comportano seria compromissione della funzione coagulativa (Harrus S. et al., 1996; Weiss D.J. et al., 1995). La leishmaniosi, in particolare, è una zoonosi largamente diffusa nelle zone costiere del Mediterraneo caratterizzata da una alterazione della coagulazione spesso asintomatica che si inserisce in un quadro sintomatologico estremamente vario. In precedenti ricerche abbiamo mostrato che, in corso di leishmaniosi, si verifica un danno piastrinico di entità variabile che, peraltro, non trova completa risoluzione con le terapie normalmente utilizzate in corso di tale patologia. I meccanismi attraverso i quali l’aggregazione piastrinica risulta alterata in corso di leishmaniosi non sono ancora chiari. Per tale motivo, l’obiettivo di questo studio è stato quello di valutare le variazioni di calcio nelle piastrine di cani sani ed affetti da leishmaniosi allo scopo di raggiungere una migliore comprensione dei meccanismi responsabili di alterazioni dell’emostasi in corso di tale patologia

    Improvement of fatty acid profile and studio of rheological and technological characteristics in breads supplemented with flaxseed, soybean, and wheat bran flours

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    Functional breads constitute an interesting alternative as vehicle of new essential fatty acids sources. The aim of this study was to improve the fatty acids (FA) profile of bakery products, producing breads with low saturated fatty acid (SFA) content and with high polyunsaturated fatty acid (PUFA) content, through partial substitution of wheat flour by other ingredients (soy flour, flax flour, and wheat bran) and to analyze the effect of this change on the technological, rheological, and sensorial characteristics of breads. Flaxseed flour (FF), soybeans flour (SF), or wheat bran (WB) was used to replace 50, 100, and 150 g kg-1 of wheat flour (WF) in breads. FF or SF produced a decrease in monounsaturated and SFA and an increase of PUFA in these breads. Furthermore, breads replaced with FF presented considerable increase in the content of n3 FA, while, SF or WB contributed to rise of linoleic and oleic FA, respectively. The substitution percentage increase of FF, SF, or WB to formulation produced changes in the colour, rheological, textural, and technological characteristics of breads. This replacement resulted in improved lipid profile, being breads with 50 g kg-1 SF, the better acceptance, baking features, and enhanced fatty acid profile.Centro de Investigación y Desarrollo en Criotecnología de Alimento
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