333 resultados para Sers, Phillipe


Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this thesis, new advances in the development of spectroscopic based methods for the characterization of heritage materials have been achieved. As concern FTIR spectroscopy new approaches aimed at exploiting near and far IR region for the characterization of inorganic or organic materials have been tested. Paint cross-section have been analysed by FTIR spectroscopy in the NIR range and an “ad hoc” chemometric approach has been developed for the elaboration of hyperspectral maps. Moreover, a new method for the characterization of calcite based on the use of grinding curves has been set up both in MIR and in FAR region. Indeed, calcite is a material widely applied in cultural heritage, and this spectroscopic approach is an efficient and rapid tool to distinguish between different calcite samples. Different enhanced vibrational techniques for the characterisation of dyed fibres have been tested. First a SEIRA (Surface Enhanced Infra-Red Absorption) protocol has been optimised allowing the analysis of colorant micro-extracts thanks to the enhancement produced by the addition of gold nanoparticles. These preliminary studies permitted to identify a new enhanced FTIR method, named ATR/RAIRS, which allowed to reach lower detection limits. Regarding Raman microscopy, the research followed two lines, which have in common the aim of avoiding the use of colloidal solutions. AgI based supports obtained after deposition on a gold-coated glass slides have been developed and tested spotting colorant solutions. A SERS spectrum can be obtained thanks to the photoreduction, which the laser may induce on the silver salt. Moreover, these supports can be used for the TLC separation of a mixture of colorants and the analyses by means of both Raman/SERS and ATR-RAIRS can be successfully reached. Finally, a photoreduction method for the “on fiber” analysis of colorant without the need of any extraction have been optimised.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The research project object of this thesis is focused on the development of an advanced analytical system based on the combination of an improved thin layer chromatography (TLC) plate coupled with infrared (FTIR) and Raman microscopies for the detection of synthetic dyes. Indeed, the characterization of organic colorants, which are commonly present in mixtures with other components and in a very limited amount, still represents a challenging task in scientific analyses of cultural heritage materials. The approach provides selective spectral fingerprints for each compound, foreseeing the complementary information obtained by micro ATR-RAIRS-FTIR and SERS-Raman analyses, which can be performed on the same separated spot. In particular, silver iodide (AgI) applied on a gold coated slide is proposed as an efficient stationary phase for the discrimination of complex analyte mixtures, such as dyes present in samples of art-historical interest. The gold-AgI-TLC plate shows high performances related both to the chromatographic separation of analytes and to the spectroscopic detection of components. The use of a mid-IR transparent inorganic salt as the stationary phase avoids interferences of the background absorption in FTIR investigations. Moreover, by ATR microscopy measurements performed on the gold-AgI surface, a considerable enhancement in the intensity of spectra is observed. Complementary information can be obtained by Raman analyses, foreseeing a SERS activity of the AgI substrate. The method has been tested for the characterization of a mixture of three synthetic organic colorants widely used in dyeing processes: Brilliant Green (BG1), Rhodamine B (BV10) and Methylene Blue (BB9).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Calcineurin-inhibitor refractory bronchiolitis obliterans (BO) represents the leading cause of late graft failure after lung transplantation. T helper (Th)2 and Th17 lymphocytes have been associated with BO development. Taking advantage of a fully allogeneic trachea transplantation model in mice, we addressed the pathogenicity of Th cells in obliterative airway disease (OAD) occurring in cyclosporine A (CsA)-treated recipients. We found that CsA prevented CD8+ T cell infiltration into the graft and downregulated the Th1 response but affected neither Th2 nor Th17 responses in vivo. In secondary mixed lymphocyte cultures, CsA dramatically decreased donor-specific IFN-γ production, enhanced IL-17 production and did not affect IL-13. As CD4+ depletion efficiently prevented OAD in CsA-treated recipients, we further explored the role of Th2 and Th17 immunity in vivo. Although IL-4 and IL-17 deficient untreated mice developed an OAD comparable to wild-type recipients, a single cytokine deficiency afforded significant protection in CsA-treated recipients. In conclusion, CsA treatment unbalances T helper alloreactivity and favors Th2 and Th17 as coexisting pathways mediating chronic rejection of heterotopic tracheal allografts.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

BACKGROUND: We aimed to study the incidence and outcome of severe traumatic brain injury (TBI) in Switzerland and to test the feasibility of a large cohort study with case identification in the first 24 hours and 6-month follow-up. METHODS: From January to June 2005, we consecutively enrolled and followed up all persons with severe TBI (Abbreviated Injury Score of the head region >3 and Glasgow Coma Scale <9) in the catchment areas of 3 Swiss medical centres with neurosurgical facilities. The primary outcome was the Extended Glasgow Outcome Scale (GOSE) after 6 months. Secondary outcomes included survival, Functional Independence Mea - sure (FIM), and health-related quality of life (SF-12) at defined time-points up to 6 months after injury. RESULTS: We recruited 101 participants from a source population of about 2.47 million (ie, about 33% of Swiss population). The incidence of severe TBI was 8.2 per 100,000 person-years. The overall case fatality was 70%: 41 of 101 persons (41%) died at the scene of the accident. 23 of 60 hospitalised participants (38%) died within 48 hours, and 31 (53%) within 6 months. In all hospitalised patients, the median GOSE was 1 (range 1-8) after 6 months, and was 6 (2-8) in 6-month survivors. The median total FIM score was 125 (range 18-126); median-SF-12 component mea - sures were 44 (25-55) for the physical scale and 52 (32-65) for the mental scale. CONCLUSIONS: Severe TBI was associated with high case fatality and considerable morbidity in survivors. We demonstrated the feasibility of a multicentre cohort study in Switzerland with the aim of identifying modifiable determinants of outcome and improving current trauma care.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

To assess the prevalence of tooth wear on buccal/facial and lingual/palatal tooth surfaces and identify related risk factors in a sample of young European adults, aged 18-35 years. Calibrated and trained examiners measured tooth wear, using the basic erosive wear examination (BEWE) on in 3187 patients in seven European countries and assessed the impact of risk factors with a previously validated questionnaire. Each individual was characterized by the highest BEWE score recorded for any scoreable surface. Bivariate analyses examined the proportion of participants who scored 2 or 3 in relation to a range of demographic, dietary and oral care variables. The highest tooth wear BEWE score was 0 for 1368 patients (42.9%), 1 for 883 (27.7%), 2 for 831 (26.1%) and 3 for 105 (3.3%). There were large differences between different countries with the highest levels of tooth wear observed in the UK. Important risk factors for tooth wear included heartburn or acid reflux, repeated vomiting, residence in rural areas, electric tooth brushing and snoring. We found no evidence that waiting after breakfast before tooth brushing has any effect on the degree of tooth wear (p=0.088). Fresh fruit and juice intake was positively associated with tooth wear. In this adult sample 29% had signs of tooth wear making it a common presenting feature in European adults.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

OBJECTIVES Dentine hypersensitivity (DH) manifests as a transient but arresting oral pain. The incidence is thought to be rising, particularly in young adults, due to increases in consumption of healthy, yet erosive, diets. This study aimed to assess the prevalence of DH and relative importance of risk factors, in 18-35 year old Europeans. METHODS In 2011, 3187 adults were enrolled from general dental practices in France, Spain, Italy, United Kingdom, Finland, Latvia and Estonia. DH was clinically evaluated by cold air tooth stimulation, patient pain rating (yes/no), accompanied by investigator pain rating (Schiff 0-3). Erosive toothwear (BEWE index 0-3) and gingival recession (mm) were recorded. Patients completed a questionnaire regarding the nature of their DH, erosive dietary intake and toothbrushing habits. RESULTS 41.9% of patients reported pain on tooth stimulation and 56.8% scored ≥1 on Schiff scale for at least one tooth. Clinical elicited sensitivity was closely related to Schiff score and to a lesser degree, questionnaire reported sensitivity (26.8%), possibly reflecting the transient nature of the pain, alongside good coping mechanisms. Significant associations were found between clinically elicited DH and erosive toothwear and gingival recession. The questionnaire showed marked associations between DH and risk factors including heartburn/acid reflux, vomiting, sleeping medications, energy drinks, smoking and acid dietary intake. CONCLUSION Overall, the prevalence of DH was high compared to many published findings, with a strong, progressive relationship between DH and erosive toothwear, which is important to recognise for patient preventive therapies and clinical management of DH pain.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

En el marco de la carrera de Licenciatura en Ciencias de la Educación se ofrece, hace cinco años, un seminario de carácter electivo sobre la propuesta pedagógica de Philippe Meirieu. Principalmente, se define este seminario de autor con el convencimiento de que su obra teórico práctica permite objetivar diversos aspectos de la trayectoria de formación de los estudiantes, tanto en su dimensión pasada como en la futura, a la vez que ampliar la reflexión sobre los intereses profesionales respecto de la educación. También, porque la mirada interdisciplinaria que sustenta la obra de P. Meirieu nos permite problematizar el proceso de producción de la teoría pedagógica a la vez que reconocer en la labor propositiva de la disciplina una diversidad de elementos estructurantes. En este sentido, nos presenta un modo posible de encarar la tarea de construir alternativas frentes los problemas de la práctica educativa, en el proceso de formación de futuros profesores y licenciados en Ciencias de la Educación. En este trabajo presentamos de modo descriptivo la propuesta del seminario a los fines de comprender los énfasis que se realizan en la enseñanza, tratando de explicitar cuestiones epistemológicas y propiamente educativas que atraviesan las discusiones en el campo de las Ciencias de la Educación y el proceso de innovación pedagógica, en términos generales, los caminos abierto por el autor a estas cuestiones y las posibilidades que estas abren. Por un lado, nos interesa indagar respecto de las posibilidades que ofrece el seminario, a los estudiantes, para el replanteo y profundización de nociones como: educación, educador, pedagogía, método, ética, escuela, disciplina, principios teóricos político pedagógicos y propuesta pedagógica y el surgimiento de intereses nuevos, suscitados por el encuentro con la propuesta del autor. La información empírica con la que contamos se corresponde a un conjunto de entrevistas en profundidad que realizamos a estudiantes que terminan el seminario, algunos de los cuales muestran un interés específico por las corrientes pedagógicas contemporáneas.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

En el marco de la carrera de Licenciatura en Ciencias de la Educación se ofrece, hace cinco años, un seminario de carácter electivo sobre la propuesta pedagógica de Philippe Meirieu. Principalmente, se define este seminario de autor con el convencimiento de que su obra teórico práctica permite objetivar diversos aspectos de la trayectoria de formación de los estudiantes, tanto en su dimensión pasada como en la futura, a la vez que ampliar la reflexión sobre los intereses profesionales respecto de la educación. También, porque la mirada interdisciplinaria que sustenta la obra de P. Meirieu nos permite problematizar el proceso de producción de la teoría pedagógica a la vez que reconocer en la labor propositiva de la disciplina una diversidad de elementos estructurantes. En este sentido, nos presenta un modo posible de encarar la tarea de construir alternativas frentes los problemas de la práctica educativa, en el proceso de formación de futuros profesores y licenciados en Ciencias de la Educación. En este trabajo presentamos de modo descriptivo la propuesta del seminario a los fines de comprender los énfasis que se realizan en la enseñanza, tratando de explicitar cuestiones epistemológicas y propiamente educativas que atraviesan las discusiones en el campo de las Ciencias de la Educación y el proceso de innovación pedagógica, en términos generales, los caminos abierto por el autor a estas cuestiones y las posibilidades que estas abren. Por un lado, nos interesa indagar respecto de las posibilidades que ofrece el seminario, a los estudiantes, para el replanteo y profundización de nociones como: educación, educador, pedagogía, método, ética, escuela, disciplina, principios teóricos político pedagógicos y propuesta pedagógica y el surgimiento de intereses nuevos, suscitados por el encuentro con la propuesta del autor. La información empírica con la que contamos se corresponde a un conjunto de entrevistas en profundidad que realizamos a estudiantes que terminan el seminario, algunos de los cuales muestran un interés específico por las corrientes pedagógicas contemporáneas.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

SeaBeam echo sounding, seismic reflection, magnetics, and gravity profiles were run along closely spaced tracks (5 km) parallel to the Atlantis II Fracture Zone on the Southwest Indian Ridge, giving 80% bathymetric coverage of a 30- * 170-nmi strip centered over the fracture zone. The southern and northern rift valleys of the ridge were clearly defined and offset north-south by 199 km. The rift valleys are typical of those found elsewhere on the Southwest Indian Ridge, with relief of more than 2200 m and widths from 22 to 38 km. The ridge-transform intersections are marked by deep nodal basins lying on the transform side of the neovolcanic zone that defines the present-day spreading axis. The walls of the transform generally are steep (25°-40°), although locally, they can be more subdued. The deepest point in the transform is 6480 m in the southern nodal basin, and the shallowest is an uplifted wave-cut terrace that exposes plutonic rocks from the deepest layer of the ocean crust at 700 m. The transform valley is bisected by a 1.5-km-high median tectonic ridge that extends from the northern ridge-transform intersection to the midpoint of the active transform. The seismic survey showed that the floor of the transform contains up to 0.5 km of sediment. Piston-coring at two locations on the transform floor recovered more than 1 m of sand and gravel, which appears to be turbidites shed from the walls of the fracture zone. Extensive dredging showed that more than two-thirds of the crust exposed in the transform valley and its walls were plutonic rocks, principally gabbros and residual mantle peridotites. In contrast, based on dredging and seafloor morphology, only relatively undisrupted pillow basalt flows have been exposed on crust of the same age spreading away from the transform. Magnetic anomalies are well defined out to 11 m.y. over the flanking transverse ridges and transform valley, even where layer 2 appears to be absent. The total opening rate is 1.6 cm/yr, but the arrangement of the anomalies indicates that the spreading for each ridge is asymmetric, with the ridge flanks facing the transform spreading at a rate of 1.0 cm/yr. Such an asymmetric spreading pattern requires that both the northern and southern ridges migrate away from each other at 0.2 cm/yr, thus lengthening the transform at 0.4 cm/yr for the last 11 m.y. To the north, the fracture zone valley is oriented differently from the present-day transform, indicating a paleospreading direction change at 17 m.y. from N10°E to due north-south. This change placed the transform into extension for the 11-m.y. period required for simple orthogonal ridge-transform geometry to be reestablished and produced a large transtensional basin within the transform valley. This basin was split by continued transform slip after 11 m.y., with the larger half moving to the north with the African Plate.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Organization of transgenes in rice transformed through direct DNA transfer strongly suggests a two-phase integration mechanism. In the “preintegration” phase, transforming plasmid molecules (either intact or partial) are spliced together. This gives rise to rearranged transgenic sequences, which upon integration do not contain any interspersed plant genomic sequences. Subsequently, integration of transgenic DNA into the host genome is initiated. Our experiments suggest that the original site of integration acts as a hot spot, facilitating subsequent integration of successive transgenic molecules at the same locus. The resulting transgenic locus may have plant DNA separating the transgenic sequences. Our data indicate that transformation through direct DNA transfer, specifically particle bombardment, generally results in a single transgenic locus as a result of this two-phase integration mechanism. Transgenic plants generated through such processes may, therefore, be more amenable to breeding programs as the single transgenic locus will be easier to characterize genetically. Results from direct DNA transfer experiments suggest that in the absence of protein factors involved in exogenous DNA transfer through Agrobacterium, the qualitative and/or quantitative efficiency of transformation events is not compromised. Our results cast doubt on the role of Agrobacterium vir genes in the integration process.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Surface-enhanced raman scattering (SERS) spectra of self-assembled monolayers of 4-aminobenzenethiol (4-ABT) on copper (Cu) and silver (Ag) surfaces decorated with Cu and Ag nanostructures, respectively, have been obtained with lasers at 532, 632.8, 785, and 1064 nm. Density functional theory (DFT) has been used to obtain calculated vibrational frequencies of the 4-ABT and 4,4′-dimercaptoazobenzene (4,4′-DMAB) molecules adsorbed on model Cu surfaces. The features of the SERS spectra depend on the electrode potential and the type and power density of the laser. SERS spectra showed the formation of the 4,4′-DMAB on the nanostructured Cu surface independently of the laser employed. For the sake of comparison SERS spectra of a self-assembled monolayer of the 4-ABT on Ag surfaces decorated with Ag nanostructures have been also obtained with the same four lasers. When using the 532 and 632.8 nm lasers, the 4,4′-DMAB is formed on Cu surface at electrode potentials as low as −1.0 V (AgCl/Ag) showing a different behavior with respect to Ag (and others metals such as Au and Pt). On the other hand, the surface-enhanced infrared reflection absorption (SEIRA) spectra showed that in the absence of the laser excitation the 4,4′-DMAB is not produced from the adsorbed 4-ABT on nanostructured Cu in the whole range of potentials studied. These results point out the prevalence of the role of electron–hole pairs through surface plasmon activity to explain the obtained SERS spectra.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This layer is a georeferenced raster image of the historic paper map entitled: Grund Riss der Ka�. K�ningl. residenz stadt Wien unter glorw�rdigster Regierung be�der ma�ten. Josephs des IIten. R�m. Ka�sers un Mari� Theresi� R�m. Ka�serin und Apost. K�nigin auf allerh�chsten Befehl, unter der Direction dero hof Mathematici Joseph Nagel aufgenommen von den N.�. Reg.Ingenieur Franz Gruss und Joseph Ne�ssner ; J.E. Mansfeld Sculp. It was published in 1770. Scale [ca. 1:1,300]. Covers Vienna, Austria. This layer is image 1 of 4 total images, representing the southeast portion of the four sheet source map. Map in German. The image inside the map neatline is georeferenced to the surface of the earth and fit to the MGI 3-Degree Gauss Kruger coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map.This map shows features such as roads, drainage, built-up areas and selected buildings, fortification and more.This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.