197 research outputs found

    Rock mass characterization by UAV and close-range photogrammetry: A multiscale approach applied along the vallone dell’elva road (Italy)

    Get PDF
    Geostructural rock mass surveys and the collection of data related to discontinues provide the basis for the characterization of rock masses and the study of their stability conditions. This paper describes a multiscale approach that was carried out using both non-contact techniques and traditional support techniques to survey certain geometrical features of discontinuities, such as their orientation, spacing, and useful persistence. This information is useful in identifying the possible kinematics and stability conditions. These techniques are extremely useful in the case study of the Elva valley road (Northern Italy), in which instability phenomena are spread across 9 km in an overhanging rocky mass. A multiscale approach was applied, obtaining digital surface models (DSMs) at three different scales: large-scale DSM of the entire road, a medium-scale DSM to assess portions of the slope, and a small-scale DSM to assess single discontinuities. The georeferenced point cloud and consequent DSMs of the slopes were obtained using an unmanned aerial vehicle (UAV) and terrestrial photogrammetric technique, allowing topographic and rapid traditional geostructural surveys. This technique allowed us to take measurements along the entire road, obtaining geometrical data for the discontinuities that are statistically representative of the rock mass and useful in defining the possible kinematic mechanisms and volumes of potentially detachable blocks. The main purpose of this study was to analyse how the geostructural features of a rock mass can affect the stability slope conditions at different scales in order to identify road sectors susceptible to different potential failure mechanisms using only kinematic analysis

    Simulation of temperature and chemical weathering effect on marble rocks

    Get PDF
    Physical and mechanical properties of building stones can vary due to different degradation mechanisms caused by temperature and chemical agents. The problem of chemical and thermal weathering on marble rocks is an important issue to consider for designing building façades since it may cause sugaring, bowing, cracking and spalling. Moreover, an accurate comprehension of induced damages is required for restoration and conservation of heritage monument purposes. While thermal weathering has been widely studied in the last years, the combined effect of thermal and chemical weathering (that here is intended as the combined action of rainwater and atmospheric pollutants) is still poorly understood. In this study, no- destructive (ultrasonic pulse velocities) and destructive tests (bending tests) were performed on Carrara marble slabs in natural and after thermal (with target temperatures respectively of 50 and 90°C) and thermo-chemical treatment. Thermo-chemical treatments were performed by soaking the specimens in a 5x10-6 mol/l solution of sulphuric acid at pH=5 to simulate the acid rain behavior, at constant target temperatures, for one week. In general, for each weathering mechanism, progressive degradation of the physical and mechanical properties of marble specimens was observed. In particular, a marked drop in flexural strength, mirrored by a wide variation in P- and S-wave velocity, was found in specimens chemically treated at target temperature equal to 90 °C

    Geostructural and geomechanical study of the piastrone quarry (Seravezza, Italy) supported by photogrammetry to assess failure mode

    Get PDF
    The use of non-contact-techniques for rock mass characterization has been growing significantly over the last decade. However, their application to stability assessment of ornamental stone has not yet received much attention from researchers. This study utilizes rock mass data both in terms of slope orientations and degree of fracturing obtained from a point cloud, a set of three-dimensional (3D) points representing a rock mass surface, to (1) investigate the influence of geostructures at different scales and (2) assess quarry stability by determining areas susceptible to different failure types. Multi-resolution point clouds are obtained through several photogrammetric survey techniques to identify important structural elements of the site. By integrating orientation data of discontinuity planes, obtained with a traditional survey, and of traces, outlined on point clouds, several joint sets were identified. Kinematic tests revealed various potential failure modes of the rock slope. Moreover, an analysis of the influence of the discontinuity strength determined by the presence of rock bridges was carried out. The study revealed that the strength of the quarry face is governed by the presence of rock bridges that act to improve the stability condition of the rock fronts

    STRUCTURAL AND FUNCTIONAL-CHARACTERIZATION OF THE PROMOTER REGIONS OF THE NFKB2 GENE

    Get PDF
    In order to clarify the transcriptional regulation of the NFKB2 gene (lyt-10, NF-kappa Bp100), we have characterized the structure and function of its promoter regions. Based on the nucleotide sequence of cDNA clones and the 5' flanking genomic region of the NFKB2 gene, RT-PCR analysis in a number of human cell lines demonstrated the presence of two alternative noncoding first exons (Ia and Ib). Two distinct promoter regions, P1 and P2, were identified upstream of each exon, containing multiple sites of transcription initiation, as shown by RNase protection analysis. Sequence analysis of these regions showed a CAAT box upstream of exon Ia and high G-C content regions within both P1 and P2. Consensus binding sites for transcription factors, including SP1, API and putative NF-kappa B (kappa B sites), were found upstream of each exon. In particular, six kappa B sites were identified, all but one of them capable of binding NF-kappa B complexes in vitro. Transfection in HeLa cells of plasmids containing PI and P2 sequences linked to a chloramphenicol acetyltransferase reporter gene indicated that both P1 and P2 can act independently as promoters. Co-transfection of NF-kappa B effector plasmids (NF-kappa Bp5a and RelA) with a reporter gene linked to P1 and P2 showed that the NFKB2 promoter regions are regulated by NF-kappa B factors. RelA transactivates the NFKB2 promoter in a dose-dependent manner, whereas NF-kappa Bp52 acts as a repressor, indicating that the NFKB2 gene may be under the control of a negative feedback regulatory circuit

    Electrophoretic variants in three Amerindian tribes: The Baniwa, Kanamari, and Central Pano of Western Brazil

    Full text link
    Data are presented on electrophoretic variants of 25 polypeptides found in the blood serum and erythrocytes, in 812 individuals from three Amerindian tribes, the Pano, the Baniwa, and the Kanamari. Two “private polymorphisms” were encountered, of PEPB in the Pano and CAII in the Baniwa. A single example of a different PEPB variant was encountered in the Baniwa, and two possible examples of an unstable variant of HGB A 2 in the Kanamari. In addition, the well-known A variant of ACP 1 , the Duarte variant of GALT, the 2 variant of Hp and the 2 variant of PGM 1 occurred in polymorphic proportions in all three tribes, and the TF D Chi variant was present as a polymorphism in the Baniwa. These data have recently been incorporated into a treatment which concludes that the eight electrophoretically-defined “private polymorphisms” thus far encountered in Amerindian tribes can be explained by a mutation pressure of 0.7 × 10 −5 /locus/generation on the assumption of neutrality of the phenotypes in question (Neel and Thompson, '78).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37590/1/1330500212_ftp.pd

    BCL10 is rarely mutated in human prostate carcinoma, small-cell lung cancer, head and neck tumours, renal carcinoma and sarcomas

    Get PDF
    We have used single-strand conformation polymorphism (SSCP) analysis to screen for mutations in the BCL 10 gene in 81 primary prostate carcinomas, 20 squamous cell cancers of the head and neck, 15 small-cell lung cancer cell lines, 24 renal carcinoma cell lines and 13 sarcoma cell lines. We failed to find evidence of somatically acquired mutations of the BCL10 gene suggesting that BCL 10 does not play a major role in the development of these malignancies
    • 

    corecore