Analytical Description of X-Ray Peaks: Application to L X-Ray Spectra Processing of Lanthanide Elements by Means of the Electron Probe Micro-Analyzer

The shape of Lα X-ray peaks analyzed by means of a LiF (200 plane) monochromator was described by a pseudo-Voigt function: P(λ) = 0.35 P1(λ)+ 0.65 P2(λ) where P1(λ) and P2(λ) are a Gaussian and a Lorentzian distribution centered at the same wavelength, with the same amplitude and half-width and in relative proportion 0.35 and 0.65 respectively. For peaks occurring at wavelength greater than ≃ 0.17 nm, a Gaussian offset was added in order to correct the asymmetry of peaks resulting from the monochromator mounting within the spectrometer. The effective wavelength resolution was obtained by quadrature addition of the instrumental resolution and the natural width of the X-ray peaks. It has been shown that the difference in peak width of the L emission peaks of the lanthanide elements resulted from their difference in their natural widths. For these elements, the Lβ2, Lγ1 and Lγ2 were found to be accompanied by non-diagram lines, Lβ14, Lγ9 and Lγ10 respectively. The wavelength separation distances Lβ14-Lβ2, Lγ9-Lγ1 and Lγ10-Lγ2 were found consistent with the distances derived from the plasmon theory

Cathodoluminescence Applied to the Microcharacterization of Mineral Materials: A Present Status in Experimentation and Interpretation

Experimentation and interpretation of cathodoluminescence (CL) microscopy and spectroscopy applied to the microcharacterization of material minerals are reviewed. The origins of the intrinsic (host lattice) and extrinsic (impurities) luminescence emissions in crystals are briefly discussed. Merits and limitations of the available techniques are illustrated. CL emission changes as a function of the incident electron dose are illustrated for the case of natural quartz and sphalerite (ZnS) crystals. These effects are discussed in terms of the development of bulk charging, production of heat, diffusion of impurities, and creation of lattice defects induced by the incident ionizing particles. Although CL emission is mostly extrinsic in origin there is no general rule for identifying the nature of impurities from the CL emission spectra of minerals. However there is potential for using CL spectroscopy for trace element analysis as presented for the case of minerals containing rare-earth luminescent ions. The CL emission is a signature of the crystal-chemistry properties of minerals and hence contains potential genetic information. Some of the applications of CL emissions in the geosciences are summarized

Scanning Mechanical Microscopy of Laser Ablated Volumes Related to Inductively Coupled Plasma-Mass Spectrometry

Scanning mechanical microscopy based on the point by point sampling of the target surface was used to characterize volumes of minerals ablated by laser pulses (Nd: YAG, = 1064 nm, 140 μs pulse-width). Differentiated volumes resulting from vaporization and exfoliation mechanisms were selectively measured. Ablated volumes of natural pyrite (cubic FeS2), marcasite (orthorhombic FeS2) and arsenopyrite AsFeS, were transported into an inductively coupled plasma torch for subsequent mass analysis. The log of the S34 Fe57, and As75 mass intensities was linearly correlated with the log of the dimensions of the vaporized crater induced by the laser shots while large particles had no effect on the measured intensities. A memory effect for As was observed when a nylon tube was used to carry the ablated materials into the plasma torch. The memory effect was decreased by using a copper tube resulting probably from a difference in the electrical properties of the tubing systems leading to a lower adsorption of As within the copper tube than for the case of the nylon tube

Une analyse en ondelettes par quintes

A wavelet analysis is introduced for discrete and periodic signals, which generalises to a scale ratio of 3/2 what is usually don e with a scale ratio of 2 . In this new context, we describe a fast transform algorithm similar to the one given in [l ], called T.O.R, and we show how can be considered an analogue to Mallat's algorithm .On introduit, pour des signaux discrétisés et périodisés, une analyse par ondelettes généralisant à un rapport d'échelles égal à 3/2 ce qui se pratique habituellement pour un rapport d'échelles égal à 2. On décrit dans ce nouveau contexte un algorithme de transformation rapide analogue à l'algorithme décrit dans [1] sous le nom de T.O.R et on montre comment peut également être envisagé un algorithme analogue à celui développé par Mallat

Resiliencia de la cubierta vegetal en un área de montaña mediterránea afectada por el fuego: el caso del incendio de Río Verde (provincia de Málaga, sur de España)

The study aim is the comparison of the vegetation cover type before and 22-years after a wildfire in order to evaluate its post-fire resilience as well as the effect of topographic attributes. The study area is that affected by a wildfire in 1991 (Río Verde, Sierra de las Nieves). By means of remote sensing and mapping techniques, the type of vegetation cover was obtained for 1991, just before the wildfire, and for 2013. The comparison of both years indicates 50% of the burned area recovered the pre-fire vegetation cover, while 1/3 presented a major vegetation cover and a type of cover more evolved. Generally speaking, after the wildfire, the most influential topographic features in the vegetal cover evolution were slope gradient, altitude and radiationEl propósito de este estudio es comparar el tipo de cubierta vegetal antes de un incendio y varios años después para evaluar su resiliencia post-incendio, así como la influencia de ciertos atributos topográficos. El área de estudio es el área afectada por el incendio de río Verde, en 1991 (Sierra de las Nieves), con una orografía muy abrupta. Mediante el tratamiento y análisis de imágenes de satélite y posterior procesamiento cartográfico en un SIG, se obtuvieron los tipos de cubierta vegetal en 1991, justo antes del incendio, y en 2013. De la comparación de ambos años, puede decirse que, tras 22 años desde el incendio, la mitad del área quemada ha recuperado la cubierta vegetal previa y 1/3 de la misma presenta actualmente una cubierta vegetal superior, con un tipo de cubierta que evidencia un estado evolutivo más avanzado respecto al determinado antes del incendio. En general, los atributos topográficos que más influyeron en la evolución post-incendio de la cubierta vegetal fueron, en este orden, pendiente, altitud y radiación

Expression of the immune modulator secretory leukocyte protease inhibitor (SLPI) in colorectal cancer liver metastases and matched primary tumors is associated with a poorer prognosis

Secretory leukocyte protease inhibitor (SLPI), a pleiotropic protein expressed by healthy intestinal epithelial cells, functions as an inhibitor of NF-κB and neutrophil proteases and exerts antimicrobial activity. We previously showed SLPI suppresses intestinal epithelial chemokine production in response to microbial contact. Increased SLPI expression was recently detected in various types of carcinoma. In addition, accumulating evidence indicates SLPI expression is favorable for tumor cells. In view of these findings and the abundance of SLPI in the colonic epithelium, we hypothesized SLPI promotes colorectal cancer (CRC) growth and metastasis. Here, we aimed to establish wh

Identification of key genes for carcinogenic pathways associated with colorectal adenoma-to-carcinoma progression

Colorectal adenomas form a biologically and clinically distinct intermediate stage in development of colorectal cancer (CRC) from normal colon epithelium. Only 5% of adenomas progress into adenocarcinomas, indicating that malignant transformation requires other biological alterations than those involved in adenoma formation. The present study aimed to explore which cancer-related biological processes are affected during colorectal adenoma-to-carcinoma progression and to identify key genes within these pathways that can serve as tumor markers for malignant transformation. The activity of 12 cancer-related biological processes was compared between 37 colorectal adenomas and 31 adenocarcinomas, using the pathway analysis tool Gene Set Enrichment Analysis. Expression of six gene sets was significantly increased in CRCs compared to adenomas, representing chromosomal instability, proliferation, differentiation, invasion, stroma activation, and angiogenesis. In addition, 18 key genes were identified for these processes based on their significantly increased expression levels. For AURKA and PDGFRB, increased mRNA expression levels were verified at the protein level by immunohistochemical analysis of a series of adenomas and CRCs. This study revealed cancer-related biological processes whose activities are increased during malignant transformation and identified key genes which may be used as tumor markers to improve molecular characterization of colorectal tumors