1,854 research outputs found
Crop wild relatives (CWR) priority in Italy: Distribution, ecology, in situ and ex situ conservation and expected actions
The study presents an updated overview of the 14 non‐endemic threatened crop wild relatives (CWR) in Italy: Aegilops biuncialis, Ae. uniaristata, Ae. ventricosa, Asparagus pastorianus, Beta macrocarpa, Brassica insularis, B. montana, Crambe hispanica subsp. hispanica, C. tataria subsp. tataria, Ipomoea sagittata, Lathyrus amphicarpos, L. palustris, Vicia cusnae and V. serinica. Geographical distri-bution, ecology (with plant communities and habitat 92/43/EEC aspects), genetics (focused on gene pools), property, and in situ and ex situ conservation were analyzed. In addition, with the aim of their protection and valorization, specific actions are recommended
How soft is a single protein?: Stress-strain curve of antibody pentamers with 5 pN and 50 pm resolutions
Understanding the mechanical functionalities of complex biological systems requires the measurement of the mechanical compliance of their smallest components. Here, we develop a force microscopy method to quantify the softness of a single antibody pentamer by measuring the stress–strain curve with force and deformation resolutions, respectively, of 5 pN and 50 pm. The curve shows three distinctive regions. For ultrasmall compressive forces (5–75 pN), the protein's central region shows that the strain and stress are proportional (elastic regime). This region has an average Young's modulus of 2.5 MPa. For forces between 80 and 220 pN, the stress is roughly proportional to the strain with a Young's modulus of 9 MPa. Higher forces lead to irreversible deformations (plastic regime). Full elastic recovery could reach deformations amounting to 40% of the protein height. The existence of two different elastic regions is explained in terms of the structure of the antibody central region. The stress–strain curve explains the capability of the antibody to sustain multiple collisions without any loss of biological functionality.This work was supported by grants from MINECO (Spain), CSD2010-00024 and the European Research Council ERC-AdG-340177 (3DNanoMech)Peer reviewe
IUCN red list evaluation of the orchidaceae endemic to apulia (Italy) and considerations on the application of the IUCN protocol to rare species
The conservation status of the ten taxonomically currently recognised orchid species and subspecies (eight in the genus Ophrys, and one each in the genera Epipactis and Serapias) endemic to Apulia (southeast Italy) is presented. Each taxon has been assessed against the internationally accepted IUCN criteria and categories. Of the ten taxa, eight ones are classified as threatened (Endangered or Vulnerable), one as Near Threatened and one as Least Concern. Given that nine of the ten analysed taxa were recently assessed, a comparison with the previous assessments is presented: 67% of the assessed taxa changed their IUCN category. Four taxa (Ophrys murgiana, O. oxyrrhynchos subsp. ingrassiae, O. peucetiae, O. tardans) are now assigned to a higher threat category, while two taxa (Ophrys gravinensis and O. oestrifera subsp. montis-gargani) are now assigned to a lower threat category. These category changes in such a very short time are due to the better knowledge on the number of mature individuals and on the threats affecting the species, and to the discovery of new occurring sites. The most important category change affects Ophrys tardans. The new assessment leads to the category Endangered, whereas in the previous assessment this species was indicated as Least Concern, i.e. as not threatened. Another species with a noteworthy category increase is Ophrys peucetiae, previously indicated as Least Concern and now assigned to the category Vulnerable. The authors discuss these results, highlighting that especially when assessing rare species with a small distribution range against the IUCN protocol, it should be taken into account that the assessment could be influenced (also noteworthy) by the effective knowledge on the distribution, on the population size and on the threats affecting the populations. As a consequence, field work is warmly suggested before assessing the threat category of rare taxa, given that an increased effort in field research often leads to the discovery of new sites and to a better estimation of the number of individuals and of the threats
Oxidative potential associated with urban aerosol deposited into the respiratory system and relevant elemental and ionic fraction contributions
Size-segregated aerosol measurements were carried out at an urban and at an industrial site. Soluble and insoluble fractions of elements and inorganic ions were determined. Oxidative potential (OP) was assessed on the soluble fraction of Particulate Matter (PM) by ascorbic acid (AA), dichlorofluorescein (DCFH) and dithiothreitol (DTT) assays. Size resolved elemental, ion and OP doses in the head (H), tracheobronchial (TB) and alveolar (Al) regions were estimated using the Multiple-Path Particle Dosimetry (MPPD) model. The total aerosol respiratory doses due to brake and soil resuspension emissions were higher at the urban than at the industrial site. On the contrary, the doses of anthropic combustion tracers were generally higher at the industrial site. In general, the insoluble fraction was more abundantly distributed in the coarse than in the fine mode and vice versa for the soluble fraction. Consequently, for the latter, the percent of the total respiratory dose deposited in TB and Al regions increased. Oxidative potential assay (OPAA) doses were distributed in the coarse region; therefore, their major contribution was in the H region. The contribution in the TB and Al regions increased for OPDTT and OPDCFH
Atomic force microscopy dynamic modes for the quantification of nanomechanical properties: From polymers to membrane proteins
A thesis submitted to the Universidad Autónoma de Madrid in accordance with the requirements of the degree of
Doctor in Philosophy.[EN] The atomic force microscope (AFM) has been established as the key tool for the development and the study of Nanoscience and Nanotechnology fields. The expansion of AFM configurations has increased its versatility and, now, it is possible to obtain high resolution images, meaning atomic and molecular resolution, on a broad variety of materials such as semiconductors, metals, polymers or biomolecules. In addition, the AFM works in all environments, from vacuum to liquid.The AFM has evolved as a response to the need to provide non-invasive and high resolution methods for imaging surfaces and interfaces. These methods provide simultaneous information about different material properties which are needed to understand heterogeneous interfaces such as solid-liquid interfaces, polymer interfaces, energy-storage devices, cells or membrane proteins and to develop materials with tailored properties at the nanoscale. Ideally, those methods should complement the high spatial resolution of AFM with the following properties: (1) Material characterization independent of the probe properties. (2) Quantitative. (3) Minimal tip and sample preparation. (4) Compatible with high speed data acquisition and imaging. The approaches most widely used so far are the combination of force curves at each point of the surface with contact or near contact AFM imaging configurations. However, these approaches have some limitations, 1) The data acquisition speed is limited by the large number of data points per pixel needed to obtain accurate values of the mechanical properties, 2) The use of the same cantilever to measure complex surfaces is restricted since the sensitivity of the force curve depends on the cantilever force constant, 3) The expressions used to retrieve the mechanical properties are not analytical or there is a lack of theoretical approaches used to determine those expressions. In order to address these limitations, the development of nanomechanical spectroscopy methods has been inspired by bimodal excitation in combination with the main dynamic modes, amplitude modulation and frequency modulation.This doctoral thesis focuses on the main dynamic AFM configurations: amplitude modulation AFM (AM-AFM), frequency modulation (FM-AFM) and bimodal excitation. The thesis is divided in five chapters and has two main goals, 1) to develop new AFM techniques based on single or bimodal excitation, that connect the experimental observables and the properties of the material. The development of the AFM techniques is specifically focused on the application of the techniques in liquid for the study of the nanomechanical properties of biomolecules and biomaterials in their native environment; 2) to study the established dynamic AFM modes and compare their performance for imaging biomolecules in air and liquid in a non invasive manner.[ES] La microscopía de fuerzas (AFM por sus siglas en inglés) se ha establecido como una herramienta clave para el desarrollo y estudio de la nanociencia y la nanotecnología. El desarrollo de diversos modos de operación de la micropalanca ha aumentado la versatilidad de la microscopía de fuerzas para visualizar con resolución atómica, molecular o nanométrica una gran variedad de superficies y materiales como semiconductores, metales, polímeros o biomoléculas. Además, el AFM puede funcionar tanto en vacío, como a presión atmosférica o en líquido.El AFM ha evolucionado para dar una respuesta a la necesidad de métodos de alta resolución y no invasivos para medir superficies e intercaras. Estos métodos proporcionan información simultánea de las distintas propiedades que son necesarias para entender materiales como polímeros, dispositivos para almacenamiento de energía, células o proteínas y para el desarrollo de materiales con propiedades personalizadas en la nano escala. Idealmente estos métodos deberían complementar la alta resolución proporcionada por el AFM con las siguientes propiedades: (1) Caracterización del material independientemente de las propiedades de la sonda del AFM. (2) Medidas cuantitativas. (3) Preparación de punta y muestra mínima. (4) Compatible con alta velocidad de adquisición de datos y de imagen. Hasta ahora, los métodos desarrollados utilizaban la combinación de curvas de fuerza en cada punto de la superficie de la muestra con configuraciones de AFM en contacto o fuera de resonancia. Sin embargo, estos métodos tienen algunas limitaciones, (1) Debido al gran número de puntos por pixel, la adquisición de los datos y de la imagen simultáneamente es más lento. (2) El uso del mismo cantiléver para medir superficies con distintas propiedades no es posible debido a que la sensibilidad de las curvas de fuerzas depende de la constante de fuerzas del cantiléver. (3) Las ecuaciones desarrolladas para obtener las propiedades mecánicas no son analíticas, aumentando el tiempo de adquisición de los datos.En algunos casos la teoría para el desarrollo de estas ecuaciones no está explicada. Todas estas limitaciones han llevado a la comunidad de AFM a desarrollar métodos basados en la excitación bimodal en combinación con los principales modos dinámicos, amplitud modulada y frecuencia modulada.Esta tesis doctoral se centra en las distintas configuraciones de AFM con los modos dinámicos: amplitud modulada (AM-AFM), frecuencia modulada (FM-AFM) y excitación bimodal. La tesis se divide en cinco capítulos y tiene dos objetivos principales, a) El desarrollo de nuevas técnicas de AFM, basadas en excitación simple o bimodal, que permiten conectar los observables experimentales con las propiedades del material. El desarrollo de las técnicas de AFM está especialmente enfocado en la aplicación de las técnicas en líquido para el estudio de las propiedades mecánicas de biomoléculas y biomateriales en su medio nativo; 2) El estudio de los modos dinámicos del AFM ya establecidos y comparar su comportamiento para medir biomoléculas en aire y en liquido de forma no invasiva.Peer reviewe
Subsurface imaging of silicon nanowire circuits and iron oxide nanoparticles with sub-10 nm spatial resolution
Non-destructive subsurface characterization of nanoscale structures and devices is of significant interest in nanolithography and nanomanufacturing. In those areas, the accurate location of the buried structures and their nanomechanical properties are relevant for optimization of the nanofabrication process and the functionality of the system. Here we demonstrate the capabilities of bimodal and trimodal force microscopy for imaging silicon nanowire devices buried under an ultrathin polymer film. We resolve the morphology and periodicities of silicon nanowire pairs. We report a spatial resolution in the sub-10 nm range for nanostructures buried under a 70 nm thick polymer film. By using numerical simulations we explain the role of the excited modes in the subsurface imaging process. Independent of the bimodal or trimodal atomic force microscopy approach, the fundamental mode is the most suitable for tracking the topography while the higher modes modulate the interaction of the tip with the buried nanostructures and provide subsurface contrast.This work was funded by the European Union FP7/2007-2013 under Grant Agreement No. 318804 (SNM), the Ministerio de Economía y Competitividad (Spain) under grants MAT2013-44858-R, CSD2010-00024 and the European Research Council ERC-AdG-340177 (3DNanoMech).Peer reviewe
Imaging Tests for Predicting the Presence of Difficult Airway in Head and Neck Cancer Patients Undergoing Otorhinolaryngological Surgery
Patients with head and neck cancers represent a challenge for the surgical team from many points of view, but, especially, the surgical moment where greater stress generated corresponds to the perioperative management of the airway, because in many occasions we can face unexpected situations, most of the time, incidental findings can hinder ventilation and endotracheal intubation. Gutierrez et al., in 2018, decided to study four tomography measures and their correlation in anesthesia records with airway management difficulties. Material and methods: A retrospective, observational study was carried out in 104 patients operated by head and neck cancers over a period of 36 months, only in those with access to tomographic records. Four tomographic measurements were considered and were statistically related to the extreme degrees of visualization of the glottis (Cormack III–IV) and the presence of the physical examination of Mallampati III–IV. Results: After performing a multivariate model in the group of extreme degrees of visualization of the glottis, the results were not statistically significant (p > 0.05; 95% CI: 0.030–2.31: EPI/PPW, 0.018–1.37 TB/PPW). In the Mallampati III–IV group, in the multivariate model only the VC/PPW showed clinically significant results (p < 0.05; 95% CI: 0.104–8.53). Conclusions: Tomographic measurements and the physical examination predictors could represent a useful guide in the prediction of the difficult airway in these patients
ATLAS RPC Quality Assurance results at INFN Lecce
The main results of the quality assurance tests performed on the Resistive
Plate Chamber used by the ATLAS experiment at LHC as muon trigger chambers are
reported and discussed.
Since July 2004, about 270 RPC units has been certified at INFN Lecce site
and delivered to CERN, for being integrated in the final muon station of the
ATLAS barrel region.
We show the key RPC characteristics which qualify the performance of this
detector technology as muon trigger chamber in the harsh LHC enviroments.
These are dark current, chamber efficiency, noise rate, gas volume
tomography, and gas leakage.Comment: Comments: 6 pages, 1 table, 9 figures Proceedings of XXV Physics in
Collision-Prague, Czech Republic, 6-9 July 200
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