170 research outputs found

    Sodium butyrate in growing and fattening diets for early-weaned rabbits

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    [EN] To study the effect of adding coated sodium butyrate (SB) to growing-fattening rabbit diets, 2 trials were conducted. In trial 1, 180 rabbits were housed in pairs and fattened from 23 (weaning) to 63 d of age to evaluate their zootechnical performance. Trial 2 involved 30 rabbits, from 23 to 37 d of age and housed individually in digestibility cages, to evaluate digestibility, caecal fermentative activity and morphology of the intestinal mucosa. In both trials rabbits were randomly divided into 2 groups, each receiving one of the following diets: control diet [CTR, 360 g neutral detergent fibre (NDF) and 170 g crude protein (CP)/kg dry matter (DM)] and SB diet. The SB diet, similar to CTR diet, included coated SB at 5 g/kg by replacement of an identical quantity of wheat. In trial 1, after the first 2 wk, the SB content was reduced from 5 to 3 g/kg. In trial 2, faeces were collected over the last 6 d (32-37 d of age), with rabbits being slaughtered at 37 d of age. Gastric and caecal pH were measured and fermentative activity was determined in caecal contents. Three sections of the small intestine were excised from 20 rabbits (10 per treatment) for microscopic examination of intestinal villi and crypts in the proximal region, central region and distal region. In the first 2 wk after weaning, SB rabbits grew 8% less than their counterparts (P=0.002), but had a better feed conversion ratio (1.58 vs. 1.61; P=0.036). During the whole trial 1 period, SB improved feed conversion (P=0.005) and decreased feed intake (104.1 CTR vs. 98.8 g/d SB; P=0.017). No difference was recorded in daily weight gain (42.7 vs. 42.9 g/d). In both diets, the digestibility of DM, organic matter, energy, CP and NDF were similar. In the 3 intestinal regions of rabbits fed SB diet, crypts were deeper (P<0.05). There were no significant differences in villus height and width between treatments. Pectinase activity was higher (P=0.054) with SB diet, but cellulase and xylanase activity remained unaffected by diet. In our experimental conditions, the addition of SB allowed an improvement in feed conversion.Ribeiro, J.; Gaspar, S.; Pinho, M.; Freire, JPB.; Falcão-E-Cunha, L. (2012). Sodium butyrate in growing and fattening diets for early-weaned rabbits. World Rabbit Science. 20(4):199-207. doi:10.4995/wrs.2012.1233SWORD19920720

    From Bloch Oscillations to a Steady-State Current in Strongly Biased Mesoscopic Devices

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    It has long been known that quantum particles in a periodic lattice exhibit an oscillatory motion that is solely driven by a constant and uniform force field. In a strongly biased mesoscopic device, this would appear as an ongoing time-dependent current oscillation (a Bloch oscillation) but, even when electrons can move coherently and without scattering, a steady-state regime of charge transport (a Landauer current) have been seen to quickly emerge. Here, we theoretically investigate the non-equilibrium current dynamics of a strongly biased two-terminal mesoscopic device, in order to show that such a system can exhibit Bloch oscillations as a transient regime that relaxes into a Landauer steady-state from charge being drained into the leads. Analytical results from the one-dimensional Wannier-Stark ladder problem are combined with numerical quantum time-evolution of a tight-binding toy model with finite leads to characterize the decay times of transient Bloch oscillations and establish the conditions under which they can occur.Comment: Preliminary Version (13 pages + 12 Figures). Comments and Suggestions are Welcome

    Salt effects on the solubility of aromatic and dicarboxylic amino acids in water

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    The salt effect on the solubility of the amino acids l-aspartic acid, l-glutamic acid, l-tryptophan, and l-tyrosine, seldomly found in the literature, was studied at 298.2 K, in aqueous solutions of KCl and (NH4)2SO4, for salt concentrations up to 2.0 mol·kg−1. In this concentration range, both salts are salting-in agents for glutamic acid and aspartic acid, with a stronger effect induced by (NH4)2SO4. Regarding the two aromatic amino acids, a slight increase in the solubility was obtained at low salt concentrations, followed by a stronger salting-out effect, more pronounced by (NH4)2SO4 than by KCl. The relative solubility data obtained in this work were compared to literature data for other amino acids in the same electrolyte solutions to establish a relative solubility ranking connected to their structure. Finally, the solubility data were modeled using the electrolyte Perturbed-Chain Statistical Association Theory (ePC-SAFT). The modeling requires parameters for the amino acids and ions as well as melting properties of the amino acids. All these parameters and properties were obtained from previous works. To quantitatively describe the solubility of amino acids upon salt addition, binary interaction parameters (kij) between any amino acid and anions were determined, while between any amino acid and the cations were fixed to kij = 0.08. The kij parameters between amino acid and the inorganic anions show very similar values for amino acids of the same chemical class (e.g. kij between anion and amino acid with apolar side chains), which may be used to systematically reduce the number of adjustable parameters in future work.publishe

    Flow field of non-Newtonian fluids in impinging jets confined by slopping plane walls

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    An experimental investigation was carried out to characterize the flow field in a liquid impingingjet confined by slopping plane walls and emanating from a rectangular duct for various non-Newtonianfluids. These jets are frequently found in processes within the food and pharmaceutical industries, and theyare formed when a high velocity fluid impinges a solid surface leading to intense levels of heat and masstransfer. The experimental work is complemented by results from a numerical investigation for purelyviscous fluids. This work continues previous research, Cavadas et al (2006), on the same flow geometry forNewtonian fluids in laminar and turbulent flow regimes. Here detailed measurements of mean flow fieldswere carried out by laser-Doppler anemometry at inlet duct Reynolds numbers of Kozicki (1966) (Re*) of200 pertaining to the laminar flow regime. The two non-Newtonian fluids were aqueous solutions of xanthangum (XG) and polyacrylamide (PAA) at weight concentrations of 0.2% and 0.125%, respectively. ForNewtonian fluids, Cavadas et al (2006) found a characteristic three-dimensional helical flow inside therecirculation, starting at the symmetry plane and evolving towards the flat side walls. This helical floweliminates the separated flow region near the side walls and was also visualized in the non-Newtonian cases.Before reaching the flat side walls, the fluid in helical motion exits the recirculation and joins the main flowstream creating a near-wall jet which can be seen as velocity peaks near the walls in the spanwise profiles ofstreamwise velocity. The numerical simulations investigated the roles of shear-thinning and inertia on themain flow characteristics for purely viscous fluids at Reynolds numbers between 10 and 800. The length ofthe recirculation (XR) is constant in the central portion of the channel and decays to zero before reaching theflat side walls. At high Reynolds numbers a slight increase in XR at the edge of the core of the flow isapparent. As expected, inertia increases the length of the recirculation as for Newtonian fluids, but somewhatsurprisingly it also increases the three-dimensional nature of the flow by reducing the size of the central core.Shear-thinning enhances the role of inertia especially at high Reynolds numbers, whereas at low Reynoldsnumbers the behavior is quite similar for all fluids. All flow fields were found to be symmetric relative to x-zand x-y centre plane

    Classificação Geotécnica do maciço rochoso da Pedreira do Monte das Flores – Évora (Portugal)

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    No âmbito da atualização do processo de homologação da Pedreira do Monte das Flores - Évora, como fornecedora de balastro ferroviário, procedeu-se à classificação geotécnica do maciço rochoso existente no local. Esta exploração possui 96,90 ha de área arrendada estando 70,70 ha concessionados à exploração. Geologicamente, a área estudada pertence à Zona de Ossa-Morena (Maciço de Évora), enquanto parte integrante do Maciço Ibérico que constitui o setor mais ocidental e contínuo da Cadeia Orogénica Varisca na Europa. Também os eventos tectonotérmicos alpinos se fizeram sentir neste maciço de forma atenuada, permitindo a preservação da história geológica mesozóica [Moita, 2008]. A unidade geológica onde se insere a exploração é constituída por litótipos ígneos e metamórficos de idade precâmbrica e paleozóica [Andrade et al., 1976], denotando-se um domínio das formações de rochas eruptivas. Na área estudada ocorre um afloramento de quartzodiorito e granodiorito de grão médio, não porfiróide, onde os minerais mais representativos da rocha são o feldspato potássico, a plagioclase e o quartzo, sem evidenciarem qualquer orientação à vista desarmada [Moita, 2008]. Neste estudo fez-se a descrição geotécnica da qualidade do maciço rochoso que ocorre na Pedreira do Monte das Flores. Por se tratar de um sistema de classificação generalista e correntemente utilizado na avaliação do comportamento geomecânico dos maciços rochosos, utilizou-se a Descrição Geotécnica Básica (“Basic Geotechnical Description”- BGD), proposta pela Sociedade Internacional de Mecânica das Rochas [ISRM, 1981]. O principal objetivo da aplicação desta classificação foi o de efetuar um zonamento geotécnico do maciço rochoso, quer do local atualmente em exploração, quer da área contígua para onde se prevê o alargamento da corta da exploração, com base no reconhecimento geológico e, na amostragem efetuada em locais selecionados para posterior realização de ensaios laboratoriais de caracterização mecânica. Este reconhecimento geológico de superfície permitiu identificar o tipo de rocha presente, determinar as características estruturais e caracterizar a alteração do maciço rochoso, assim como, definir as diferentes famílias de fraturas presentes e quantificar o espaçamento entre as descontinuidades nestas famílias. Com o objetivo de determinar as características mecânicas, tais como, a resistência à compressão uniaxial e o ângulo de atrito das fraturas, foi realizada uma campanha de ensaios laboratoriais e de campo, nomeadamente, o ensaio de resistência à compressão uniaxial, complementado pelo ensaio de carga pontual, de modo a determinar o valor daquela resistência. Realizou-se também o ensaio com o martelo de Schmidt dado ser um ensaio simples e rápido na caracterização de materiais [Pinho, 2003], que permite estimar o valor da resistência à compressão uniaxial dos planos das descontinuidades do maciço rochoso (JCS), nos diferentes locais de amostragem. O parâmetro JCS, o coeficiente de rugosidade da descontinuidade (JRC) e a tensão efectiva normal (’n ), foram necessários para obter o ângulo de atrito das diaclases (Øpico), de acordo com o método proposto pela Sociedade Internacional de Mecânica das Rochas [ISRM, 1978]. O estudo realizado permitiu concluir que o maciço apresenta boa qualidade, em regra, homogénea relativamente às suas características geológicas e geotécnicas. No entanto, distinguem-se duas zonas, ZG1 e ZG2, com base em pequenas diferenças nos valores da resistência à compressão uniaxial da rocha e do ângulo de atrito das fraturas

    Immature hard ticks infected with Rickettsia amblyommatis on breeding birds from Pantanal

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    Immature hard ticks from the genus Amblyomma feed on blood from a wide range of Neotropical avian hosts. They serve as vectors for pathogens of medical and veterinary importance, such as Rickettsia agents of the spotted fever group (SFG). Hence, determining ecological factors that increase encounter rates between immature ticks and their avian hosts may contribute to the understanding of tick-borne diseases transmission. Here, we used 720 individual birds from 96 species surveyed in the Brazilian Pantanal to test whether host breeding season influenced tick infestation probabilities. Additionally, collected ticks were screened for Rickettsia agents to describe new avian-tick-bacteria associations. Our models revealed that the probability of an individual bird being infested with immature ticks was similar during the breeding and pre-breeding season, but higher loads of immature tick stages were found during the breeding season. Host sex did not predict infestation probability, but Rickettsia agents recovered from ticks were more prevalent during the pre-breeding season. The new records of host usage by larvae and nymphs of Amblyomma in Pantanal and the growing body of tick surveys in Neotropical avian communities, suggest that immature ticks may benefit from avian blood sources during their annual cycle. The low number of infected ticks with Rickettsia agents on Pantanal birds suggest that this vertebrate group are likely not acting as reservoirs for these microorganisms. However, long-term surveys at the same site are imperative to determine which tick species are acting as reservoirs for Rickettsia agents in Pantanal and determine whether birds are playing a role in dispersing ticks and tick-borne pathogens.Fil: Fecchio, Alan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónica. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina. Universidade Federal Do Mato Grosso (ufmt);Fil: Martins, Thiago Fernandes. Universidade de Sao Paulo; Brasil. Secretaria de Estado Da Saude de Sao Paulo; BrasilFil: Dias, Raphael I.. Universidade do Brasília; BrasilFil: Bell, Jeffrey A.. University Of North Dakota; Estados UnidosFil: Pinho, João B.. Universidade Federal Do Mato Grosso (ufmt);Fil: Silva, Victoria Luiza de Barros. Universidade Federal Do Mato Grosso (ufmt);Fil: Pacheco, Richard de Campos. Universidade Federal Do Mato Grosso (ufmt)

    Assessment of the tolerability and cycle control of two low-dose oral contraceptives: an open-label study

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    An open-label comparative study was conducted in nine centers in Brazil to evaluate the tolerability and cycle control of two low-dose oral contraceptives containing 20 mg ethynylestradiol/75 mg gestodene and 20 mg ethynylestradiol/150 mg desogestrel, during six treatment cycles. A total of 167 healthy sexually active women were enrolled (77 in the gestodene group and 90 in the desogestrel group) and 138 completed the six-cycle treatment period. A lipid and hemostatic profile was performed for a subgroup of first users. A total of 867 cycles were evaluated. Irregular bleeding did not occur in 95.4% of the cycles evaluated with gestodene and in 91.9% with desogestrel. Tolerability was good with both preparations but there was significantly more nausea in the desogestrel group. Cycle control was good with both preparations with a significantly lower incidence of irregular bleeding with gestodene when all cycles were considered. There were no clinically significant changes in the hemostatic profile. Lipid profile showed a trend to be more favorable after six cycles of treatment with both preparations. Women in the gestodene group did not present changes in the mean weight; in the desogestrel group there was a significant mean weight increase of 1 kg after six cycles of treatment. Compliance with treatment was good with both preparations. Results of this study demonstrated that low-dose preparations containing gestodene or desogestrel combined with 20 mg of ethynylestradiol are well-tolerated oral contraceptives that provide good cycle control.Realizou-se um estudo aberto comparativo em nove centros brasileiros para avaliar a tolerabilidade e o controle de ciclo obtido com o uso de dois contraceptivos orais de baixa dose contendo 20 mg etinilestradiol/75 mg gestodeno e 20 mg etinilestradiol/150 mg desogestrel, durante seis ciclos de tratamento. Foram selecionadas 167 mulheres saudáveis com vida sexual ativa (77 no grupo do gestodeno e 90 no grupo do desogestrel), das quais 138 completaram os seis ciclos de tratamento. Em um subgrupo de novas usuárias realizou-se também perfil lipídico e hemostático. Foram avaliados 867 ciclos no total. Ocorreu sangramento irregular em 4,6% dos ciclos com gestodeno e em 8,1% com desogestrel. A tolerabilidade a ambas preparações foi boa, mas houve significativamente mais náusea no grupo do desogestrel. O controle de ciclo foi bom com os dois contraceptivos, sendo que houve freqüência significativamente menor de sangramento irregular no grupo do gestodeno quando se leva em conta que todos os ciclos foram considerados. Não houve alterações clinicamente significativas no perfil hemostático. O perfil lipídico mostrou tendência a tornar-se mais favorável após seis ciclos de tratamento com as duas preparações. Não ocorreu alteração no peso médio das mulheres no grupo do gestodeno; no grupo do desogestrel houve aumento significativo no peso médio de aproximadamente 1 kg após seis meses de tratamento. A adesão ao tratamento foi boa com as duas preparações. Os resultados deste estudo mostram que preparações contendo baixa dose de gestodeno ou desogestrel associados a 20 mg de etinilestradiol são contraceptivos bem tolerados que permitem bom controle de ciclo, sem efeitos colaterais significantes.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUniversidade Federal da Bahia Faculdade de MedicinaSecretaria Estadual de Saúde de Goiás Hospital Materno-InfantilUniversidade Federal do Ceará Faculdade de MedicinaUniversidade de São Paulo Faculdade de MedicinaFaculdade de Ciências Médicas do Espírito SantoUniversidade Federal do Pará Faculdade de MedicinaUniversidade Federal do Pernambuco Faculdade de MedicinaUniversidade Federal da Paraíba Faculdade de MedicinaUNIFESP, EPMSciEL

    11th national meeting of organic chemistry and 4th meeting of therapeutic chemistry

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    This work received financial support from the European Union (FEDER funds through COMPETE) and National Funds (FCT, Fundação para a Ciência e Tecnologia) through project UID/QUI/50006/2013. Fátima Fernandes (SFRH/BPD/98732/2013) and Mariana Barbosa (SFRH/BD/95861/2013) thank FCT for the grants.For the first time under the auspices of Sociedade Portuguesa de Química, the competences of two important fields of Chemistry are brought together into a single event, the 11st National Organic Chemistry Meeting and the the 4th National Medicinal Chemistry Meeting, to highlight complementarities and to promote new synergies. Abstracts of plenary lectures, oral communications, and posters presented during the meeting are collected in this report.publishersversionpublishe

    Cholesteryl hemiesters alter lysosome structure and function and induce proinflammatory cytokine production in macrophages

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    Rationale: Cholesteryl hemiesters are oxidation products of polyunsaturated fatty acid esters of cholesterol. Their oxo-ester precursors have been identified as important components of the "core aldehydes" of human atheromata and in oxidized lipoproteins (Ox-LDL). We had previously shown, for the first time, that a single compound of this family, cholesteryl hemisuccinate (ChS), is sufficient to cause irreversible lysosomal lipid accumulation (lipidosis), and is toxic to macrophages. These features, coupled to others such as inflammation, are typically seen in atherosclerosis. Objective: To obtain insights into the mechanism of cholesteryl hemiester-induced pathological changes in lysosome function and induction of inflammation in vitro and assess their impact in vivo. Methods and results: We have examined the effects of ChS on macrophages (murine cell lines and primary cultures) in detail. Specifically, lysosomal morphology, pH, and proteolytic capacity were examined. Exposure of macrophages to sub-toxic ChS concentrations caused enlargement of the lysosomes, changes in their luminal pH, and accumulation of cargo in them. In primary mouse bone marrow-derived macrophages (BMDM), ChS-exposure increased the secretion of IL-1 beta, TNF-alpha and IL-6. In zebrafish larvae (wild-type All and PU.1:EGFP), fed with a ChS-enriched diet we observed lipid accumulation, myeloid cell-infiltration in their vasculature and decrease in larval survival. Under the same conditions the effects of ChS were more profound than the effects of free cholesterol (FC). Conclusions: Our data strongly suggest that cholesteryl hemiesters are pro-atherogenic lipids able to mimic features of Ox-LDL both in vitro and in vivo.NOVA4Health - UID/Multi/04462/2013, a program financially supported by Fundação para a Ciência e Tecnologia (FCT)/Ministério da Educação e Ciência, through national funds and co-funded by FEDER under the PT2020 Partnership Agreement. FCT fellowship references: SFRH/BPD/26843/2006, SFRH/BD/62126/2009, SFRH/BD/90258/2012, SFRH/BD/84685/2012, SFRH/BPD/102229/2014, SFRH/BD/52293/2013info:eu-repo/semantics/publishedVersio
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