1,259 research outputs found

    Simplified analysis of cantilever diaphragm walls in cohesive soils

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    Abstract In this paper, a method is presented for a simplified analysis of cantilever diaphragm walls in cohesive soils under undrained and drained conditions. A rectilinear distribution of the net contact stresses that are not completely predetermined by the limit state is assumed at the soil-wall interface, consistently with the mechanism usually experienced by these structures. Simple equations are derived to readily calculate the contact stress distribution on the wall and the associated internal forces in the ultimate and service conditions. Moreover, these equations require few parameters as input data. Comparisons are carried out with a limit equilibrium method commonly used in design to show the usefulness of the proposed method for practical purposes

    Simplified Methods for the Dynamic Analysis of Single Pile in Layered Soils

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    In this paper, two simplified methods are used to calculate the impedance function of an axially loaded pile embedded in layered soils. The methods are: a semi-analytical procedure which uses the discrete layer stiffness matrices derived by Kausel and Roesset (1981), and the cone model which was developed by Wolf et al. (1992). A number of comparisons with more rigorous solutions are shown in order to assess the accuracy of the methods used

    Settlements of Three Buildings Founded on Stratified Soils

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    This paper describes the movements experienced by three residential buildings located in Avellino (South Italy). A common feature of the buildings is the unsymmetrical superstructure that, for lack of construction joints, makes the resultant of the vertical loads on foundation to be highly eccentric. At the end of December 1983, when most of the dead loads had been applied, the buildings exhibited conspicuous settlements, so construction was stopped and the vertical displacement of several points of the foundation was measured during a period of almost one year. The subsoil was investigated by boreholes, CPT and conventional laboratory tests; it consists of a sequence of compressible layers of silty sand and clayey silt, overlying a gravel formation. The thickness of these layers was found to be very different from borehole to borehole. An analysis of the movements occurred is conducted using a finite element code. Good agreement is found between theoretical prediction and experimental measurements. The analysis has also shown that the compressibility and heterogeneity of the subsoil along with the eccentricity of loads on foundation were the main causes for the movements occurred

    Hydrogen-Enhanced Gasoline Stratified Combustion in SI-DI Engines

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    ABSTRACT Experimental investigations were carried out to assess the use of hydrogen in a Gasoline Direct Injection (GDI) engine. Injection of small amounts of hydrogen (up to 27% on energy basis) in the intake port creates a reactive homogeneous background for the direct injection of gasoline in the cylinder. In this way, it is possible to operate the engine with high EGR rates and, in certain conditions, to delay the ignition timing as compared to standard GDI operation, in order to reduce NOx and HC emissions to very low levels and possibly soot emissions. The results confirmed that high EGR rates can be achieved and NOx and HC emissions reduced, showed significant advantage in terms of combustion efficiency and gave unexpected results relative to the delaying of ignition, which only partly confirmed the expected behavior. A realistic application would make use of hydrogen-containing reformer gas produced on board the vehicle, but safety restrictions did not allow using carbon monoxide in the test facility. Thus pure hydrogen was used for a best-case investigation. The expected difference in the use of the two gases is briefly discussed

    Studio di procedure ed esempio applicativo per lo sviluppo e controllo di software per Programmable Electric Medical System (PEMS) secondo EN60601-1:2006 e 21CFR820

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    Tirocinio per studio delle procedure aziendali ed esempio pratico applicativo per lo sviluppo e il controllo di programmable electric medical system (PEMS) secondo le norme EN60601-1:2006 e 21CFR820ope

    Prediction of Slow-Moving Landslide Mobility Due to Rainfall Using a Two-Wedges Model

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    In the present study, the landslides cyclically reactivated by water-table oscillations due to rainfall are dealt with. The principal kind of motion that usually characterizes such landslides is a slide with rather small velocity. As another feature, soil deformations are substantially accumulated inside a narrow shear zone situated below the landslide body so that the latter approximately slides rigidly. Within this framework, a new approach is developed in this paper to predict the mobility of this type of landslides due to rainfall. To this end, a two-wedges model is used to schematize the moving soil mass. Some analytical solutions are derived to link rain recordings with water-table fluctuations and in turn to landslide displacements. A well-documented landslide frequently activated by rainfall is studied to check the forecasting capacity of the proposed method

    Kinematics of the Maierato Landslide (Calabria, Southern Italy)

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    Abstract On 15 February 2010, a landslide of great dimensions occurred at Maierato (Southern Italy) after a long rainy period. Although the zone was continuously affected by movements, no monitoring system was installed before the landslide. However, many photos were taken to document the occurrence of deformations and two videos were filmed during the paroxysmal phase of the event. Photos and videos are used in the present study to reconstruct the kinematics of the landslide. A geotechnical model of the slope is also defined on the basis of the results from field and laboratory tests

    Rare breast cancer subtypes: Histological, molecular, and clinical peculiarities

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    Breast cancer encompasses a collection of different diseases characterized by different biological and pathological features, clinical presentation, response to treatments, clinical behavior, and outcome. On the basis of cell morphology, growth, and architecture patterns, breast cancer can be classified in up to 21 distinct histological types. Breast cancer special types, including the classic lobular invasive carcinoma, represent 25% of all breast cancers. The histological diversity of breast carcinomas has relevant prognostic implications. Indeed, the rare breast cancer group includes subtypes with very different prognoses, ranging from the tubular carcinoma, associated with an indolent clinical course, to metaplastic cancer, whose outcome is generally unfavorable. New approaches based on gene expression profiling allow the identification of molecularly defined breast cancer classes, with distinct biological features and clinical behavior. In clinical practice, immunohistochemical classification based on the expression of human epidermal growth factor receptor 2 and Ki67 is applied as a surrogate of the intrinsic molecular subtypes. However, the identification of intrinsic molecular subtypes were almost completely limited to the study of ductal invasive breast cancer. Moreover, some good-prognosis triple-negative histotypes, on the basis of gene expression profiling, can be classified among the poor-prognosis group. Therefore, histopathological classification remains a crucial component of breast cancer diagnosis. Special histologies can be very rare, and the majority of information on outcome and treatments derives from small series and case reports. As a consequence, clear recommendations about clinical management are still lacking. In this review, we summarize current knowledge about rare breast cancer histologies.Breast cancer encompasses a collection of different diseases characterized by different biological and pathological features, clinical presentation, response to treatments, clinical behavior, and outcome. On the basis of cell morphology, growth, and architecture patterns, breast cancer can be classified in up to 21 distinct histological types. Breast cancer special types, including the classic lobular invasive carcinoma, represent 25% of all breast cancers. The histological diversity of breast carcinomas has relevant prognostic implications. Indeed, the rare breast cancer group includes subtypes with very different prognoses, ranging from the tubular carcinoma, associated with an indolent clinical course, to metaplastic cancer, whose outcome is generally unfavorable. New approaches based on gene expression profiling allow the identification of molecularly defined breast cancer classes, with distinct biological features and clinical behavior. In clinical practice, immunohistochemical classification based on the expression of human epidermal growth factor receptor 2 and Ki67 is applied as a surrogate of the intrinsic molecular subtypes. However, the identification of intrinsic molecular subtypes were almost completely limited to the study of ductal invasive breast cancer. Moreover, some good-prognosis triple-negative histotypes, on the basis of gene expression profiling, can be classified among the poor-prognosis group. Therefore, histopathological classification remains a crucial component of breast cancer diagnosis. Special histologies can be very rare, and the majority of information on outcome and treatments derives from small series and case reports. As a consequence, clear recommendations about clinical management are still lacking. In this review, we summarize current knowledge about rare breast cancer histologies. \ua9 AlphaMed Press

    Case Report: Generalized Mutual Information (GMI) Analysis of Sensory Motor Rhythm in a Subject Affected by Facioscapulohumeral Muscular Dystrophy after Ken Ware Treatment

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    In this case report we study the dynamics of the SMR band in a subject affected from Facioscapulohumeral Muscular Dystrophy and subjected to Ken Ware Neuro Physics treatment. We use the Generalized Mutual Information (GMI) to analyze in detail the SMR band at rest during the treatment. Brain dynamics responds to a chaotic-deterministic regime with a complex behaviour that constantly self-rearranges and self-organizes such dynamics in function of the outside requirements. We demonstrate that the SMR chaotic dynamics responds directly to such regime and that also decreasing in EEG during muscular activity really increases its ability of self-arrangement and self-organization in brain. The proposed novel method of the GMI is arranged by us so that it may be used in several cases of clinical interest. In the case of muscular dystrophy here examined, GMI enables us to quantify with accuracy the improvement that the subject realizes during such treatment

    Differential Gene Expression Induced by Insulin and Insulin-like Growth Factor-II through the Insulin Receptor Isoform A *

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    The human insulin receptor (IR) exists in two isoforms (IR-A and IR-B). IR-A is a short isoform, generated by the skipping of exon 11, a small exon encoding for 12 amino acid residues at the carboxyl terminus of the IR alpha-subunit. Recently, we found that IR-A is the predominant isoform in fetal tissues and malignant cells and binds with a high affinity not only insulin but also insulin-like growth factor-II (IGF-II). To investigate whether the activation of IR-A by the two ligands differentially activate post-receptor molecular mechanisms, we studied gene expression in response to IR-A activation by either insulin or IGF-II, using microarray technology. To avoid the interfering effect of the IGF-IR, IGF-II binding to the IR-A was studied in IGF-IR-deficient murine fibroblasts (R- cells) transfected with the human IR-A cDNA (R-/IR-A cells). Gene expression was studied at 0.5, 3, and 8 h. We found that 214 transcripts were similarly regulated by insulin and IGF-II, whereas 45 genes were differentially transcribed. Eighteen of these differentially regulated genes were responsive to only one of the two ligands (12 to insulin and 6 to IGF-II). Twenty-seven transcripts were regulated by both insulin and IGF-II, but a significant difference between the two ligands was present at least in one time point. Interestingly, IGF-II was a more potent and/or persistent regulator than insulin for these genes. Results were validated by measuring the expression of 12 genes by quantitative real-time reverse transcriptase-PCR. In conclusion, we show that insulin and IGF-II, acting via the same receptor, may differentially affect gene expression in cells. These studies provide a molecular basis for understanding some of the biological differences between the two ligands and may help to clarify the biological role of IR-A in embryonic/fetal growth and the selective biological advantage that malignant cells producing IGF-II may acquire via IR-A overexpression
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