5,344 research outputs found
Consumo de nutrientes de dietas contendo diferentes nĂveis de farelo de melancia forrageira (Citrullus lanatus cv. Citroides), em ovinos.
Utilizou-se 20 cordeiros, com idade mĂ©dia de seis meses e peso vivo mĂ©dio de 11,2 kg (+- 1,2), submetidos a um delineamento experimental inteiramente casuaiizado, para determinar os consumos de matĂ©ria seca (MS), matĂ©ria orgĂąnica (MO), proteĂna bruta (PB), extrato etĂ©reo (EE), fibra em detergente neutro (FDN) e carboidratos totais (CHOT). Cinco dietas contendo D1:80; D2:65; D3:50; D4:35 e D5:20% de farelo de melancia como conncentrado e feno de guandu taipeiro como volumoso, foram avaliadas. As anĂĄlises estatĂsticas das variĂĄveis estudadas foram interpretadas por anĂĄlises de variĂąncia e de regressĂŁo os consumos de MS, MO, PB, CHOT e FDN, expressos em g/dia, apresentaram um comportamento quadrĂĄtico (P<0,05) com o aumento do nĂvel de farelo de melancia nas dietas, enquanto o consumo de EE nĂŁo foi alterado. As diferentes proporçÔes de farelo de melancia e feno de guandu taipeiro, utilizadas nas dietas nĂŁo proporcionaram um consumo de nutrientes adequado para ovinos
Uso do farelo de melancia forrageira (Citrullus lanatus cv. Citroides) e do feno de guandu (Cajanus cajan (L.) Millspaugh cv. D1 Type.), em dietas para ovinos: digestibilidade de nutrientes.
Para se determinarem os coeficientes de digestibilidade da matĂ©ria seca (MS), matĂ©ria (MO), proteĂna bruta (PB), extrato etĂ©reo (EE), fibra em detergente neutro (FDN) e carboidratos totais (CHOT), foi realizado um ensaio de digestibilidade, utilizando-se cinco dietas contendo D1:80; D2:65; D3:50; 1)4:35 e D5:20% de farelo de melancia como concentrado e feno de guandu taipeiro como volumoso. Vinte cordeiros mestiços, com idade mĂ©dia de seis meses e peso vivo mĂ©dio de 11,2 kg (+-1,2), foram submetidos a um delineamento inteiramente casualizado, com cinco tratamentos e quatro repetiçÔes. O nĂvel de farelo de melancia forrageira na dieta influenciou linearmente a digestibilidade aparente da MO (62 a 54%) e dos CHOT (58 a 47%). A digestibilidade da PB teve um comportamento cĂșbico. Os nĂveis de concentrado nĂŁo influenciaram a digestibilidade da MS, FDN e do EE. Pode-se concluir que os coeficientes de digestibilidade dos nutrientes das dietas, foram satisfatĂłrios e prĂłximos aos valores encontrados para algumas dietas e forrageiras utilizadas para ovinos, no semi-ĂĄrido nordestino
Spontaneous vesicle formation in catanionic mixtures of amino acid-based surfactants: Chain length symmetry effects
The use of amino acids for the synthesis of novel surfactants with vesicle-forming properties potentially enhances the biocompatibility levels needed for a viable alternative to conventional lipid vesicles. In this work, the formation and characterization of catanionic vesicles by newly synthesized lysine- and serine-derived surfactants have been investigated by means of phase behavior mapping and PFG-NMR diffusometry and cryo-TEM methods. The lysine-derived surfactants are double-chained anionic molecules bearing a pseudogemini configuration, whereas the serine-derived amphiphile is cationic and single-chained. Vesicles form in the cationic-rich side for narrow mixing ratios of the two amphiphiles. Two pairs of systems were studied: one symmetric with equal chain lengths, 2C(12)/C(12), and the other highly asymmetric with 2C(8)/C(16) chains, where the serine-based surfactant has the longest chain. Different mechanisms of the vesicle-to-micelle transition were found, depending on symmetry: the 2C12/C12 system entails limited micellar growth and intermediate phase separation, whereas the 2C(8)/C(16) system shows a continuous transition involving large wormlike micelles. The results are interpreted on the basis of currently available models for the micelle-vesicle transitions and the stabilization of catanionic vesicles (energy of curvature vs mixing entropy)
A ZZ Ceti white dwarf in SDSS J133941.11+484727.5
We present time-resolved spectroscopy and photometry of the cataclysmic
variable (CV) SDSSJ133941.11+484727.5 (SDSS1339) which has been discovered in
the Sloan Digital Sky Survey Data Release 4. The orbital period determined from
radial velocity studies is 82.524(24)min, close to the observed period minimum.
The optical spectrum of SDSS1339 is dominated to 90% by emission from the white
dwarf. The spectrum can be successfully reproduced by a three-component model
(white dwarf, disc, secondary) with Twd=12500K for a fixed log g=8.0, d=170pc,
and a spectral type of the secondary later than M8. The mass transfer rate
corresponding to the optical luminosity of the accretion disc is very
low,~1.7x10^-13Msun/yr. Optical photometry reveals a coherent variability at
641s with an amplitude of 0.025mag, which we interpret as non-radial pulsations
of the white dwarf. In addition, a long-period photometric variation with a
period of either 320min or 344min and an amplitude of 0.025mag is detected,
which bears no apparent relation with the orbital period of the system. Similar
long-period photometric signals have been found in the CVs
SDSSJ123813.73-033933.0, SDSSJ204817.85-061044.8, GW Lib and FS Aur, but so far
no working model for this behaviour is available.Comment: MNRAS, in press, 8 pages, 10 figures, some figures downgraded to meet
the file size constraint of arxiv.or
IL-17RA-signaling modulates CD8+ T Cell survival and exhaustion during trypanosoma cruzi infection
The IL-17 family contributes to host defense against many intracellular pathogens by mechanisms that are not fully understood. CD8+ T lymphocytes are key elements against intracellular microbes, and their survival and ability to mount cytotoxic responses are orchestrated by several cytokines. Here, we demonstrated that IL-17RA-signaling cytokines sustain pathogen-specific CD8+ T cell immunity. The absence of IL-17RA and IL-17A/F during Trypanosoma cruzi infection resulted in increased tissue parasitism and reduced frequency of parasite-specific CD8+ T cells. Impaired IL-17RA-signaling in vivo increased apoptosis of parasite-specific CD8+ T cells, while in vitro recombinant IL-17 down-regulated the pro-Apoptotic protein BAD and promoted the survival of activated CD8+ T cells. Phenotypic, functional, and transcriptomic profiling showed that T. cruzi-specific CD8+ T cells derived from IL-17RA-deficient mice presented features of cell dysfunction. PD-L1 blockade partially restored the magnitude of CD8+ T cell responses and parasite control in these mice. Adoptive transfer experiments established that IL-17RA-signaling is intrinsically required for the proper maintenance of functional effector CD8+ T cells. Altogether, our results identify IL-17RA and IL-17A as critical factors for sustaining CD8+ T cell immunity to T. cruzi.Fil: Tosello Boari, Jimena. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Araujo Furlan, Cintia Liliana. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Fiocca Vernengo, Facundo. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Rodriguez, Constanza. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Ramello, MarĂa Cecilia. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Amezcua Vesely, Maria Carolina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Gorosito Serran, Melisa. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Nuñez, NicolĂĄs G.. Institute Curie; Francia. Institut National de la SantĂ© et de la Recherche MĂ©dicale; FranciaFil: Richer, Wilfrid. Institut National de la SantĂ© et de la Recherche MĂ©dicale; Francia. Institute Curie; FranciaFil: Piaggio, Eliane. Institut National de la SantĂ© et de la Recherche MĂ©dicale; Francia. Institute Curie; FranciaFil: Montes, Carolina Lucia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Gruppi, Adriana. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Acosta Rodriguez, Eva Virginia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; Argentin
Qualidade e perfil de fermentação das silagens de trĂȘs cultivares de milheto.
Objetivando avaliar a qualidade e o perfil de fermentacao da silagem de milheto, foram estudados tres genotipos (CMS01, CMS02 e BN02). Os silos foram abertos com 01, 03, 05, 07, 14, 28 e 56 dias. Os teores de MS variaram de 22,64 a 24,49, a silagem foi considerada de mediana qualidade. Os teores de PB variaram de 9,59% a 11,32% nao observou-se queda acentuada durante a ensilagem. As porcentagens de N-NH3/Ntotal variaram de 3,32% a 9,01%, classificando a silagem como bem preservada. Observou-se variacao de pH de 3,56 a 5,13, estabilizando a partir do dia 14
When the optimal is not the best: parameter estimation in complex biological models
Background: The vast computational resources that became available during the
past decade enabled the development and simulation of increasingly complex
mathematical models of cancer growth. These models typically involve many free
parameters whose determination is a substantial obstacle to model development.
Direct measurement of biochemical parameters in vivo is often difficult and
sometimes impracticable, while fitting them under data-poor conditions may
result in biologically implausible values.
Results: We discuss different methodological approaches to estimate
parameters in complex biological models. We make use of the high computational
power of the Blue Gene technology to perform an extensive study of the
parameter space in a model of avascular tumor growth. We explicitly show that
the landscape of the cost function used to optimize the model to the data has a
very rugged surface in parameter space. This cost function has many local
minima with unrealistic solutions, including the global minimum corresponding
to the best fit.
Conclusions: The case studied in this paper shows one example in which model
parameters that optimally fit the data are not necessarily the best ones from a
biological point of view. To avoid force-fitting a model to a dataset, we
propose that the best model parameters should be found by choosing, among
suboptimal parameters, those that match criteria other than the ones used to
fit the model. We also conclude that the model, data and optimization approach
form a new complex system, and point to the need of a theory that addresses
this problem more generally
Electronic structure and ferroelectricity in SrBi2Ta2O9
The electronic structure of SrBi2Ta2O9 is investigated from first-principles,
within the local density approximation, using the full-potential linearized
augmented plane wave (LAPW) method. The results show that, besides the large
Ta(5d)-O(2p) hybridization which is a common feature of the ferroelectric
perovskites, there is an important hybridization between bismuth and oxygen
states. The underlying static potential for the ferroelectric distortion and
the primary source for ferroelectricity is investigated by a lattice-dynamics
study using the Frozen Phonon approach.Comment: 17 pages, 7 figures. Phys. Rev. B, in pres
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SREBP1-induced fatty acid synthesis depletes macrophages antioxidant defences to promote their alternative activation
Macrophages exhibit a spectrum of activation states ranging from classical to alternative activation1. Alternatively, activated macrophages are involved in diverse pathophysiological processes such as confining tissue parasites2, improving insulin sensitivity3 or promoting an immune tolerant microenvironment that facilitates tumour growth and metastasis4. Recently, the role of metabolism regulating macrophage function has come into focus as both the classical and alternative activation programmes require specific regulated metabolic reprogramming5. While most of the studies regarding immunometabolism have focussed on the catabolic pathways activated to provide energy, little is known about the anabolic pathways mediating macrophage alternative activation. In this study, we show that the anabolic transcription factor sterol regulatory element binding protein 1 (SREBP1) is activated in response to the canonical Th2 cytokine interleukin 4 (IL-4) to trigger the de novo lipogenesis (DNL) programme, as a necessary step for macrophage alternative activation. Mechanistically, DNL consumes NADPH, partitioning it away from cellular antioxidant defences and raising ROS levels. ROS serves as a second messenger, signalling sufficient DNL, and promoting macrophage alternative activation. The pathophysiological relevance of this mechanism is validated by showing that SREBP1/DNL is essential for macrophage alternative activation in vivo in a helminth infection model.This work was supported by the British Heart Foundation (RG/18/7/33636), the MRC (MC_UU_00014/2) and the FP7 MITIN (223450). K.P. was a recipient of a fellowship from the Wellcome Trust. A.N.J.M. and E.J. are supported by the Wellcome Trust (100963/Z/13/Z) and the MRC (U105178805). J.L. is a recipient fellowship of the British Heart Foundation. A.D. was a Marie-Curie Early-Stage Researcher supported by the European Unionâs Horizon 2020 research and innovation programme (675585 Marie-Curie ITN âSymBioSysâ) to J.S.-R. A.K. is supported by the Wellcome Trust (106260/Z/14/Z) and an ERC award (648889). P.F. is supported by the Science Foundation Ireland (10/IN.1/B3004). The IMS Genomics and Transcriptomics and Histology cores (B.M.-A., B.Y.H.L. and M.K.M.) are funded by the UK MRC Metabolic Disease Unit (MRC_MC_UU_12012/5) and a Wellcome Trust Strategic Award (100574/Z/12/Z). The Disease Model Core is part of the MRC Metabolic Diseases Unit (MRC_MC_UU_12012/5) and Wellcome Trust Strategic Award (100574/Z/12/Z)
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