97 research outputs found
Unexpected morphological variability in the eggshells of the South American caimans Caiman latirostris and Caiman yacare
Eggshell morphology is a valuable indicator of the local conditions within the nests of modern crocodilians and birds. In contrast to these latter, the anatomical structure of the eggshells of most crocodilian species is practically unknown. Here, we provide the first characterization of crocodilian eggshells, using x-ray micro-CT scans. We studied eggshells of Caiman latirostris and Caiman yacare from various developmental stages that coincide with the beginning of embryonic ossification. The new 3D renderings revealed complex ornamentation, unique among crocodilians, and amphora-shaped pore canals, some of which converge in single pore openings. We also documented a high density of pore canals with a gas diffusion capacity 45 times higher than the average predicted for modern avian eggshells. The external ornamentation and the thickness of the compact layer of the eggshells (i.e. excluding ornamentation) showed ontogenetic and interspecific differences that could be related to nesting materials and nesting areas selected by each species. The shell features described here evidence a greater structural complexity than previously recognized in phylogenetically close, sympatric crocodilian species. Further comprehensive morphological analyses on other modern and fossil crocodilian eggshells using micro-CT technology will shed new light on the evolution of reproductive strategies in this intriguing archosaur clade.Fil: Hechenleitner, Esteban MartĂn. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Regional de Investigaciones CientĂficas y Transferencia TecnolĂłgica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones CientĂficas y Transferencia TecnolĂłgica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones CientĂficas y Transferencia TecnolĂłgica de La Rioja. - SecretarĂa de Industria y MinerĂa. Servicio GeolĂłgico Minero Argentino. Centro Regional de Investigaciones CientĂficas y Transferencia TecnolĂłgica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones CientĂficas y Transferencia TecnolĂłgica de La Rioja; ArgentinaFil: Fernandez Blanco, MarĂa Victoria. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. DivisiĂłn PaleontologĂa Vertebrados; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata; ArgentinaFil: NĂșñez Campero, Segundo Ricardo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Regional de Investigaciones CientĂficas y Transferencia TecnolĂłgica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones CientĂficas y Transferencia TecnolĂłgica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones CientĂficas y Transferencia TecnolĂłgica de La Rioja. - SecretarĂa de Industria y MinerĂa. Servicio GeolĂłgico Minero Argentino. Centro Regional de Investigaciones CientĂficas y Transferencia TecnolĂłgica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones CientĂficas y Transferencia TecnolĂłgica de La Rioja; ArgentinaFil: Fiorelli, Lucas Ernesto. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Regional de Investigaciones CientĂficas y Transferencia TecnolĂłgica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones CientĂficas y Transferencia TecnolĂłgica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones CientĂficas y Transferencia TecnolĂłgica de La Rioja. - SecretarĂa de Industria y MinerĂa. Servicio GeolĂłgico Minero Argentino. Centro Regional de Investigaciones CientĂficas y Transferencia TecnolĂłgica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones CientĂficas y Transferencia TecnolĂłgica de La Rioja; ArgentinaFil: Bona, Paula. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. DivisiĂłn PaleontologĂa Vertebrados; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata; Argentin
Diseño de medios quirales basados en estructuras individuales bidimensionales
In this paper, we present a new way of constructing chiral media, in 8.2-12.4 GHz band, starting from achiral individual metallic elements (right angle). We showed that an appropriate distribution of such inclusions in a dielectric host responds in a manner consistent to that obtained with other media constructed using chiral metal inclusions. Appropriately modifying the size and spatial distribution of right angles is possible to model the response of these media. The media manufactured by the inclusion of right angles can be fabricated using technology printed circuit board (PCB).IngenierĂa, Industria y ConstrucciĂł
Diseño de medios quirales basados en la distribución ordenada de manivelas
In this communication, the experimental results
obtained from the measurements of evenly distributed metallic
cranks on a dielectric plate substrate is presented. The effect we
have analyzed is the rotation of the polarization plane of an
electromagnetic wave, both in free space and inside a circular
waveguide. It is shown that the rotation of the polarization plane
by some distributions of cranks, with specific symmetry
properties, can be explicitly ascribed to a chirality effect.IngenierĂa, Industria y ConstrucciĂł
Estudio experimental de inserciones metĂĄlicas quirales en medios guiados
A new manufacturing technique of chiral material and first measurements of the rotation of the polarisation angle are presented. We have developed a flexible and low cost method to produce chiral media based on the inclusion of three segment wire hook (crank) in lossless dielectric medium. Cylindrical samples are placed into a section of circular waveguide propagating an initial single TE plane-polarised mode in the X band. The S21 parameter is measured with a rotation of the output waveguide. We have found rotations of the polarised wave produced by the samples. The effect of chirality is analyzed by chiral crank versus non-chiral staples comparison.IngenierĂa, Industria y ConstrucciĂł
Actividad electromagnética de medios quirales basados en manivelas
Materials with electromagnetic activity are usually
made by spreading helices inclusions into a host medium. In
previous work, a new manufacturing technique based on the
inclusion of few three segment wire hooks (cranks) was
presented and the rotation of the polarisation angle in circular
waveguide discussed. Here we present that the random inclusion
of many cranks into a host medium produces
electromagnetically active materials. Based on a free-wave
experimental system, we have found that the transmitted wave
through the material is rotated with respect to the incident one.
First results seem to be in agreement with the typical behaviour
of chiral media at the resonant frequency.IngenierĂa, Industria y ConstrucciĂł
Developing Chiral Media Based on the Inclusion of Metallic Cranks
A review of the manufacturing techniques for developing
chiral media based on the inclusion of cranks is presented.
Chirality is usually obtained by a randomdistribution of helices
in a host medium. Here the chiral elements are obtained by
bending thin metal-wires in three segments. We will show that a
random distribution of cranks is able of rotate the polarization
angle of the transmitted linearly polarized wave at microwave
frequencies. This effect can be enhanced by the precise location
of cranks forming a 2D periodic lattice. Several structures are
analyzed looking for isotropy, reciprocity and homogeneity.IngenierĂa, Industria y ConstrucciĂł
Metamateriales Quirales Basados en Manivelas de Cinco Segmentos
A new structure formed by five segments cranks is here presented. By using numerical simulations, we show that a material composed by a 2D periodical distribution of a unit cell based on such structures is able to produce electromagnetic rotatory dispersion and circular dichroism. The symmetry requirements on the unit cell are analyzed in order to obtain a material with homogeneous and isotropic behavior for normal incidence. The material can exhibit several resonant frequencies, where the rotation angle reaches a peak of ±90Âș and the transmitted wave changes from linear to elliptical polarization.IngenierĂa, Industria y ConstrucciĂł
Targeting fatty acid-binding protein 4 improves pathologic features of aortic stenosis
Aortic stenosis (AS) is a fibrocalcific disease of the aortic valves (AVs). Sex-differences in AS pathophysiology have recently been described. High levels of fatty acid-binding protein 4 (FAPB4) in atherosclerotic plaques have been associated with increased local inflammation, endothelial dysfunction, and plaque vulnerability. FABP4 pharmacological blockade has been shown to be effective for the treatment of atherosclerosis by modulating metabolic and inflammatory pathways. We aimed to analyze the sex-specific expression of FABP4 in AS and its potential role as a therapeutic target. A total of 226 patients (61.5% men) with severe AS undergoing surgical AV replacement were recruited. The FABP4 levels were increased in the AVs of AS patients compared to the control subjects, showing greater expression in the fibrocalcific regions. Male AVs exhibited higher levels of FABP4 compared to females, correlating with markers of inflammation (IL-6, Rantes), apoptosis (Bax, caspase-3, Bcl-2), and calcification (IL-8, BMP-2 and BMP-4). VICs derived from AS patients showed the basal expression of FABP4 in vitro. Osteogenic media induced upregulation of intracellular and secreted FABP4 levels in male VICs after 7 days, along with increased levels of inflammatory, pro-apoptotic, and osteogenic markers. Treatment with BMS309403, a specific inhibitor of FABP4, prevented from all of these changes. Thus, we propose FABP4 as a new sex-specific pharmacological therapeutic target in AS.This research was funded by Miguel Servet contract CP13/00221 from the Instituto de Salud Carlos III-FEDER, Fondo de Investigaciones Sanitarias [PI18/01875; PI21/00280]. M.G. is supported by a Miguel Servet Foundation PhD studentship, E.M.-N. is supported by a Margarita Salas postdoctoral fellowship (ULL-MS-P14), L.M. is supported by a PFIS (FI19/00302) PhD studentship, E.J. (CD19/00251) is supported by a Sara Borrell postdoctoral fellowship
Characterization of the sex-specific pattern of angiogenesis and lymphangiogenesis in aortic stenosis
Objective: We aim to analyze sex-related dierences in angiogenesis and lymphangiogenesis in aortic valves (AVs) and valve interstitial cells (VICs) from aortic stenosis (AS) patients. Approach and Results: Totally 230 patients (59% men) with severe AS undergoing surgical valve replacement were recruited. The density of total neovessels was higher in AVs from men as compared to women. Both small and medium neovessels were more abundant in menâs AVs. Accordingly, male AVs exhibited higher CD31 and VE-cadherin expressions. The levels of the pro-angiogenic markers, such as vascular endothelial growth factor (VEGF)-A, VEGF receptor (VEGFR)1, VEGFR2, insulin-like growth factor-binding protein-2 (IGFBP-2), interleukin (IL)-8, chemerin, and fibroblast growth factor (FGF)-7, were increased in AVs from men. Transforming growth factor-ÎČ expression was higher in male AVs. The expression of antiangiogenic molecules thrombospondin (Tsp)-1, endostatin, and CD36 was upregulated in male AVs, although the levels of Tsp-2, IL-4, IL-12p70, and chondromodulin-1 were similar between both sexes. The number of lymphatic vessels and the expression of the lymphangiogenic markers Lyve-1 and D2-40 was higher in menâs AV as well as VEGF-C, VEGF-D, and VEGFR3. Multivariate analyses adjusted for confounders further validated the sex-dependent expression of these targets. VICs isolated from menâs AVs secreted higher amounts of the pro-angiogenic factors, VEGF-A, VEGFR1, IGFBP-2, and FGF-7, as well as the pro-lymphangiogenic factors, VEGF-C, VEGF-D, and VEGFR3, than women without changes in antiangiogenic markers. Conclusion: Our data show that aberrant angiogenic and lymphangiogenic cues are over-represented in male AVs. Importantly, the VIC is a relevant source of multiple morphogens involved in angiogenesis and lymphangiogenesis likely endowing the AV of men with the predominant calcific AS phenotypes.This work was supported by a Miguel Servet contract (CP13/00221) and by Fondo de Investigaciones Sanitarias (PI18/01875; PI21/00280) from the Instituto de Salud Carlos III - FEDER. LM was supported by a PFIS Ph.D. studentship (FI19/00302). EJ was supported by a Sara Borrell postdoctoral fellowship (CD19/00251). EM-N was supported by a Margarita Salas postdoctoral fellowship (ULL-MS-P14). MG was supported by a Miguel Servet Foundation Ph.D. studentship
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