1,242 research outputs found

    A search for hydrogenated fullerenes in fullerene-containing planetary nebulae

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    Detections of C60 and C70 fullerenes in planetary nebulae (PNe) of the Magellanic Clouds and of our own Galaxy have raised the idea that other forms of carbon such as hydrogenated fullerenes (fulleranes like C60H36 and C60H18), buckyonions, and carbon nanotubes, may be widespread in the Universe. Here we present VLT/ISAAC spectra (R ~600) in the 2.9-4.1 microns spectral region for the Galactic PNe Tc 1 and M 1-20, which have been used to search for fullerene-based molecules in their fullerene-rich circumstellar environments. We report the non-detection of the most intense infrared bands of several fulleranes around ~3.4-3.6 microns in both PNe. We conclude that if fulleranes are present in the fullerene-containing circumstellar environments of these PNe, then they seem to be by far less abundant than C60 and C70. Our non-detections together with the (tentative) fulleranes detection in the proto-PN IRAS 01005+7910 suggest that fulleranes may be formed in the short transition phase between AGB stars and PNe but they are quickly destroyed by the UV radiation field from the central star.Comment: Accepted for publication in Astronomy & Astrophysics (7 pages, 3 figures, and 3 Tables

    Indentation Measurement in Thin Plates under Bending Using 3D Digital Image Correlation

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    T2 Q2 (39/92 Engineering, Multidisciplinary, IF = 2.838)In the current paper, a novel experimental methodology to characterize the contact behavior on thin plates under bending is presented. The method is based on the experimental measurement of the indentation observed during contact experiments. Tests were conducted using aluminum thin plates and a steel sphere to evaluate the effect of thickness and bending during contact. For this purpose, a non-contact optical technique, 3D Digital Image Correlation (3D-DIC), has been employed to measure the out-of-plane displacements experienced at the rear face of the specimens (opposite where the contact is occurring). An indirect measurement of the experimental contact law is obtained for different plate thicknesses (2 mm, 3 mm, 4 mm, 5 mm and 6 mm) as the contact load increases. An energy balance performed during contact experiments made it possible to evaluate and quantify the applied energy to generate bending and contact deformation. When the specimen thickness increases from 2 mm to 6 mm, contact deformation reaches higher values from the total applied energy. In addition, it is also possible to evaluate the portion of the elastically recovered energy for contact and bending deformation during the unloading. It has been observed that thicker specimens show a lower elastic energy recovery due to bending and a higher elastic energy recovery due to contact. Results clearly show how the ratio between absorbed and applied energy changes as the specimen thickness increases, highlighting the relevance of the proposed method for the characterization of contact behavior in thin plates.Corporación Tecnológica de Andalucía, IDEA Agency, Airbus Militar

    Alteraciones anatómicas y funcionales en la muñeca después de la fractura de la extremidad distal del radio

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    Se revisaron retrospectivamente 75 casos de fracturas de la extremidad distal del radio tratadas ortopédicamente. Los resultados se valoraron desde el punto de vista anatómico y funcional. En el 49% de los casos existió trazo articular y en el 23% se asoció la lesión de la apó- fisis estiloides del cúbito. Asimismo obtuvimos un 60% de excelentes y buenos resultados a pesar de existir en el 37% de los casos complicaciones evolutivas.A series of 75 cases with fracture of the distal radius treated by conservative methods were retrospectively reciewed. Results were evaluated from anatomical and functional standpoints. In 49% of cases there was an articular extension of the fracture, and 23% had an associated fracture of the ulnar styloid process. Satisfactory outcome was achieved in 60% of cases, although there way 37% of cases showing complications during follow-up

    Layered Software Architecture for Nanosatellites

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    Layered software architecture has been used to increase code portability and reduce development times during the Systems Development Life Cycle (SDLC). The main objective of the EMIDSS-4 project is to develop a reliable and scalable hardware and software layered architecture for data acquisition in nanosatellites. An iterative hardware/software co-design approach was employed, transitioning from an FPGA architecture to an NXP-based microcontroller. The results demonstrate that the new architecture provides continuous and adaptable data acquisition capabilities, enhancing the long-term viability of the project. In conclusion, this study contributes to the field of space exploration and lays the foundation for future research in nanosatellites.ITESO, A. C

    Promiscuous mismatch extension by human DNA polymerase lambda

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    DNA polymerase lambda (Pol λ) is one of several DNA polymerases suggested to participate in base excision repair (BER), in repair of broken DNA ends and in translesion synthesis. It has been proposed that the nature of the DNA intermediates partly determines which polymerase is used for a particular repair reaction. To test this hypothesis, here we examine the ability of human Pol λ to extend mismatched primer-termini, either on ‘open’ template-primer substrates, or on its preferred substrate, a 1 nt gapped-DNA molecule having a 5′-phosphate. Interestingly, Pol λ extended mismatches with an average efficiency of ≈10−2 relative to matched base pairs. The match and mismatch extension catalytic efficiencies obtained on gapped molecules were ≈260-fold higher than on template-primer molecules. A crystal structure of Pol λ in complex with a single-nucleotide gap containing a dG·dGMP mismatch at the primer-terminus (2.40 Å) suggests that, at least for certain mispairs, Pol λ is unable to differentiate between matched and mismatched termini during the DNA binding step, thus accounting for the relatively high efficiency of mismatch extension. This property of Pol λ suggests a potential role as a ‘mismatch extender’ during non-homologous end joining (NHEJ), and possibly during translesion synthesis

    Fracturas peritrocantéricas tratadas con el clavo proximal de fémur: Técnica y resultados

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    El Clavo Proximal de Fémur (PFN: Proximal Femoral Nail) es un sistema de osteosíntesis desarrollado por la AO/ASIF para el tratamiento quirúrgico de las fracturas de la región trocantérea del fémur y que se basa en los principios del enclavado endomedular a cielo cerrado. Se presenta un estudio prospectivo sobre 175 fracturas de cadera tratadas con P.F.N. en nuestro servicio, con un seguimiento mínimo exigido de 1 año. El 74,3% de los casos correspondieron a mujeres y el resto a hombres. La edad media fue de 81,87 años. Las fracturas se han clasificado según la AO, siendo el subtipo más frecuentemente registrado el A2. Se realizaron controles clínicos y radiológicos a los 1, 3, 6 y 12 meses. El sistema ha permitido la movilización y la deambulación precoz en la mayoría de nuestros pacientes, al igual que la consolidación de las fracturas en un tiempo aceptable (12 semanas de media). Se analizan los resultados y las diversas complicaciones registradas, así como la capacidad de recuperación de la capacidad funcional previa. El PFN se revela como un buen sistema de osteosíntesis para las fracturas de la región trocantérea del fémur, permitiendo una carga precoz que favorece la consolidación ósea. La técnica quirúrgica no es compleja, la tasa de complicaciones técnicas registradas es aceptable y los resultados globales obtenidos son equiparables e incluso superiores, en determinados aspectos, a los obtenidos con otros sistemas de osteosíntesis disponibles en el mercado para el tratamiento de este tipo de fracturas.The PFN ("proximal femoral nail") is an osteosynthesis system developed by the AO/ASIF group for the surgical treatment of fractures of the trochanteric region of the femur, which is based on the principles of closed endomedullary nailing. A prospective study of 175 hip fractures treated with the PFN is presented, with a minimum follow-up of 1 year. 74,3% of the patients were female, the rest male. The average age was 81,87 years. Fractures were classified according to the AO system, the most common sub-type recorded being the A2. Clinical and radiographic evaluations were performed at 1, 3, 6 and 12 months. The system allowed early mobilisation and walking in the majority of our patients, along with fracture consolidation in an acceptable time period (12 weeks on average). The results and the various complications recorded are analysed. The ability to recover previous walking ability was also studied. The PFN emerges as a good system of osteosynthesis for fractures of the trochanteric region of the femur, allowing early weight-bearing which favours bone consolidation. The surgical technique is not complex, the number of complications recorded is acceptable and the overall results obtained are comparable and even superior to those obtained with other osteosynthesis systems available on the market for treatment of this type of fracture

    Large Scale Flows from Orion-South

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    Multiple optical outflows are known to exist in the vicinity of the active star formation region called Orion-South (Orion-S). We have mapped the velocity of low ionization features in the brightest part of the Orion Nebula, including Orion-S, and imaged the entire nebula with the Hubble Space Telescope. These new data, combined with recent high resolution radio maps of outflows from the Orion-S region, allow us to trace the origin of the optical outflows. It is confirmed that HH 625 arises from the blueshifted lobe of the CO outflow from 136-359 in Orion-S while it is likely that HH 507 arises from the blueshifted lobe of the SiO outflow from the nearby source 135-356. It is likely that redshifted lobes are deflected within the photon dominated region behind the optical nebula. This leads to a possible identification of a new large shock to the southwest from Orion-S as being driven by the redshifted CO outflow arising from 137-408. The distant object HH 400 is seen to have two even further components and these all are probably linked to either HH 203, HH 204, or HH 528. Distant shocks on the west side of the nebula may be related to HH 269. The sources of multiple bright blueshifted Herbig-Haro objects (HH 202, HH 203, HH 204, HH 269, HH 528) remain unidentified, in spite of earlier claimed identifications. Some of this lack of identification may arise from the fact that deflection in radial velocity can also produce a change in direction in the plane of the sky. The best way to resolve this open question is through improved tangential velocities of low ionization features arising where the outflows first break out into the ionized nebula.Comment: Astronomical Journal, in press. Some figures are shown at reduced resolution. A full-resolution version is available at http://ifront.org/wiki/Orion_South_Outflows_Pape
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