1,765 research outputs found

    The reptile type specimens preserved in the Museo Nacional de Ciencias Naturales (CSIC) of Madrid, Spain

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    13 páginas, 3 figuras y 2 tables.A first complete list of the reptile type specimens preserved in the Museo Nacional de Ciencias Naturales (CSIC) of Madrid (updated until 15 July 2012) is provided. The collection houses a total of 318 type specimens representing 24 taxa belonging to 6 families and 12 genera. There are 22 taxa represented by primary types (19 holotypes, 2 neotypes and 1 lectotype) and at least one paratype, and only two taxa are exclusively represented by one secondary type (paratype). The collection is specially rich in Spanish endemisms. Special attention is deserved by the type series of many subspecies of Podarcis lilfordi described by A. Salvador and V. Pérez-Mellado. All type specimens are housed in the Herpetological collection except Blanus mariae and Psammodromus occidentalis type series and Psammodromus hispanicus (neotype) which are preserved in the DNA/Tissues Collection.For the technical support we thank the projects CGL2008-04164 (Dr. I. de la Riva, Principal Investigator), HUM2007- 62687 (Dr C. Martín, Principal Investigator) and Fauna Ibérica Project CGL2007-66786-C08-01 (Dr. Marian Ramos, Principal Investigator).Peer reviewe

    In vitro hydrolytic degradation of polyester-based scaffolds under static and dynamic conditions in a customized perfusion bioreactor

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    Creating biofunctional artificial scaffolds could potentially meet the demand of patients suffering from bone defects without having to rely on donors or autologous transplantation. Three-dimensional (3D) printing has emerged as a promising tool to fabricate, by computer design, biodegradable polymeric scaffolds with high precision and accuracy, using patient-specific anatomical data. Achieving controlled degradation profiles of 3D printed polymeric scaffolds is an essential feature to consider to match them with the tissue regeneration rate. Thus, achieving a thorough characterization of the biomaterial degradation kinetics in physiological conditions is needed. Here, 50:50 blends made of poly(e-caprolactone)–Poly(D, L-lactic-co-glycolic acid (PCL-PLGA) were used to fabricate cylindrical scaffolds by 3D printing (Ø 7 × 2 mm). Their hydrolytic degradation under static and dynamic conditions was characterized and quantified. For this purpose, we designed and in-house fabricated a customized bioreactor. Several techniques were used to characterize the degradation of the parent polymers: X-ray Photoelectron Spectroscopy (XPS), Gel Permeation Chro-matography (GPC), Scanning Electron Microscopy (SEM), evaluation of the mechanical properties, weigh loss measurements as well as the monitoring of the degradation media pH. Our results showed that flow perfusion is critical in the degradation process of PCL-PLGA based scaffolds implying an accelerated hydrolysis compared to the ones studied under static conditions, and up to 4 weeks are needed to observe significant degradation in polyester scaffolds of this size and chemical composition. Our degradation study and characterization methodology are relevant for an accurate design and to tailor the physicochemical properties of polyester-based scaffolds for bone tissue engineering

    Imagen ecográfica de la obstrucción biliar extrahepática en el perro : descripción de 7 casos

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    Se realizó un estudio ecográfico en siete perros que presentaban un cuadro de ictericia por obstrucción biliar extrahepática. Esta técnica permitió llegar al diagnóstico en seis de los casos. Se estudió la imagen ecográfica de la dilatación de las vías biliares intra y extrahepáticas, así como los signos asociados, tales como la presencia de una masa en el área pancreática, que pudiesen orientar sobre el origen de la obstrucción.An ultrasonographic examination was carried in out 7 dogs with icterus due to an extrahepatic biliary obstruction. This technique allowed the diagnosis in 6 of the dogs. The sonographic appearance of the dilated intra and extrahepatic biliary tree was assessed, as well as the associated lesions, such as the presence of a mass in the pancreatic area, which could guide towards the origin of the obstruction

    Lump solitons in a higher-order nonlinear equation in 2+1 dimensions

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    We propose and examine an integrable system of nonlinear equations that generalizes the nonlinear Schrodinger equation to 2 + 1 dimensions. This integrable system of equations is a promising starting point to elaborate more accurate models in nonlinear optics and molecular systems within the continuum limit. The Lax pair for the system is derived after applying the singular manifold method. We also present an iterative procedure to construct the solutions from a seed solution. Solutions with one-, two-, and three-lump solitons are thoroughly discussed

    CUIDADOS DE ENFERMERÍA EN EL PACIENTE SOMETIDO A TRASPLANTE DE MÉDULA.

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    The aim of this article is to describe what a bone-marrow transplant is, how it is practiced, what possible difficulties may come up throughout the whole process and what our nursing intervention will be. The official definition of the nursing diagnosis of NAIDA connects specifically the diagnosis to the nursing interventions. But, what happens with other clinical situations (those not covered by nursing diagnosis) which need nursing interventions? Where can they fit within the field of clinical practice? In 1983, Carpenito presented a pattern for the practice which describes the clinical perspectives of nurses. The bifocal model about clinical practice identifies the clinical situations where nurses intervene, both as a primary assistant and collaborating with other disciplines. Based on the diagnoses described by L.J. Carpenito, we elaborate the different nursing activities.El objetivo de este artículo es describir qué es el trasplante de médula, cómo se realiza, qué complicaciones médicas pueden surgir a lo largo de todo el proceso y cuál va ser nuestra actuación enfermera. La definición oficial de diagnóstico de enfermería de la NANDA vincula de forma específica el diagnóstico con las intervenciones de enfermería. Pero, ¿qué sucede con otras situaciones clínicas (no cubiertas por los diagnósticos de enfermería) que necesitan intervenciones de enfermería? ¿Dónde pueden encajar en el ámbito de la práctica clínica? En 1983, Carpenito presentó un modelo para la práctica que describe la perspectiva clínica de las enfermeras. El modelo bifocal de práctica clínica identifica las situaciones clínicas en las que intervienen las enfermeras: como asistente primario y en colaboración con otras disciplinas. Basándonos en los diagnósticos descritos por L. J. Carpenito vamos a elaborar también las diferentes actividades de enfermería

    Spin dynamics in helical molecules with nonlinear interactions

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    It is widely admitted that the helical conformation of certain chiral molecules may induce a sizable spin selectivity observed in experiments. Spin selectivity arises as a result of the interplay between a helicity-induced spin-orbit coupling (SOC) and electric dipole fields in the molecule. From the theoretical point of view, different phenomena might affect the spin dynamics in helical molecules, such as quantum dephasing, dissipation and the role of metallic contacts. With a few exceptions, previous studies usually neglect the local deformation of the molecule about the carrier, but this assumption seems unrealistic to describe charge transport in molecular systems. We introduce an effective model describing the electron spin dynamics in a deformable helical molecule with weak SOC. We find that the electron-lattice interaction allows the formation of stable solitons such as bright solitons with well defined spin projection onto the molecule axis. We present a thorough study of these bright solitons and analyze their possible impact on the spin dynamics in deformable helical molecules

    Collagen-laponite nanoclay hydrogels for tumor spheroid growth

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    The extracellular matrix (ECM) plays an important regulatory role in the development and progression of tumoral tissue. Its functions and properties are crucial in determining tumor cell behavior such as invasion, migration, and malignancy development. Our study explores the role of collagen type I in cancer development and spread using engineered tumor models like multicellular spheroids grown in collagen-based hydrogels to simulate early tumor formation. We employ microfluidic techniques to test the hypothesis that (i) adding Laponite nanoclay to collagen hydrogels modifies mechanical and rheological properties and (ii) changing the stiffness of the collagen microenvironment affects tumor spheroid growth. Our findings support our theories and suggest the use of ECM components and engineered tumor models in cancer research, offering a biocompatible and biomimetic method to tailor the mechanical properties of conventional collagen hydrogels

    Scattering effects from neighboring atoms in core-level WSe2 photoemission

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    Methods of attosecond science originally developed to investigate systems in the gas phase are currently being adapted to obtain temporal information on the electron dynamics that takes place in condensed-matter systems. In particular, streaking measurements have recently been performed to determine photoemission time delays from the WSe2 dichalcogenide. In this work we present a fully atomistic description of the photoemission process in WSe2 and provide angularly resolved photoemission cross sections and time delays from the W 4f, Se 3d and Se 4s core states of the system. Since these states are spatially localized, we propose a cluster approach in which we build up from smaller to larger clusters, so that we can assess the importance of scattering effects by each new layer of neighboring atoms. We use a static-exchange density functional theory method with B-spline functions, where a one-center angular-momentum expansion is supplemented by off-center expansions with fewer partial waves. This enhances convergence in comparison with a one-center expansion, which would require very high angular momenta to characterize the localized fast oscillations near each off-center atomic core. We find that the photoemission delays and fully differential cross sections are strongly affected by scattering events that take place off the neighboring atoms, implying the need to consider their effects for quantitative descriptions of the photoemission proces

    The kinematics of the quadrupolar nebula M1-75 and the identification of its central star

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    The link between the shaping of bipolar planetary nebulae and their central stars is still poorly understood. The kinematics and shaping of the multipolar nebula M 1-75 are hereby investigated, and the location and nature of its central star are briefly discussed. Fabry-Perot data from GHaFAS on the WHT sampling the Doppler shift of the [N II] 658.3 nm line are used to study the dynamics of the nebula, by means of a detailed 3-D spatio-kinematical model. Multi-wavelength images and spectra from the WFC and IDS on the INT, and from ACAM on the WHT, allowed us to constrain the parameters of the central star. The two pairs of lobes, angularly separated by ~22 degrees, were ejected simultaneously approx. ~3500-5000 years ago, at the adopted distance range from 3.5 to 5.0 kpc. The larger lobes show evidence of a slight degree of point symmetry. The shaping of the nebula could be explained by wind interaction in a system consisting of a post-AGB star surrounded by a disc warped by radiative instabilities. This requires the system to be a close binary or a single star which engulfed a planet as it died. On the other hand, we present broad- and narrow-band images and a low S/N optical spectrum of the highly-reddened, previously unnoticed star which is likely the nebular progenitor. Its estimated V-I colour allows us to derive a rough estimate of the parameters and nature of the central star.Comment: 8 pages, 6 figures, accepted for publication in Astronomy & Astrophysic

    Effects of human versus mouse leukemia inhibitory factor on the in vitro development of bovine embryos

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    Leukemia inhibitory factor (LIF) is a cytokine that shows conflicting effects on in vitro produced (IVP) bovine embryos. Bovine LIF (bLIF) has been cloned and used in culture, but there is no commercially available bLIF. Thus, researchers use human LIF (hLIF) to supplement the culture medium for bovine embryos because of its greater sequence homology compared to murine LIF (mLIF). We compared the effects of mLIF and hLIF on the development of bovine embryos in culture with the effects described for bLIF. Oocytes were matured and fertilized in vitro and cultured in modified synthetic oviduct fluid with BSA. On Day 6 post-insemination, morulae were cultured for 48 h in the presence of: (1) mLIF, 100 ng ml−1; (2) hLIF, 100 ng ml−1; or (3) no LIF. Reduced blastocyst rates were observed on Day 8 for hLIF at the middle and expanded stages, while mLIF had no effect. In contrast, Day 8 blastocysts showed decreased cell counts both in terms of inner cell mass (ICM) and ICM/total cell proportions in the presence of mLIF, while hLIF had no effect. No changes were seen in trophectoderm (TE) and total cell counts. The increased hatching rates and TE cell counts previously described for bLIF, together with the disparate effects exhibited by hLIF and mLIF during blastocyst formation indicate these compounds are inappropriate to replace bLIF. We recommend that heterospecific LIF should not be used to supplement the culture medium for bovine embryo or embryonic stem cells
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