1,722,472 research outputs found
Globin mRNA sequences in polyadenylated and nonpolyadenylated nuclear precursor-messenger RNA from avian erythroblasts.
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Acoustic tracking system for AUVs exploiting DoA sensors -calibration and performance characterisation
No full textThis work describes the calibration procedure of a tracking system for Autonomous Underwater Vehicles (AUVs) based on Direction of Arrival (DoA) acoustic sensors. The final aim is to track the AUV along a significant set of imposed underwater trajectories and to exploit the collected dataset for identification of vehicle dynamic parameters. In the framework of this activity, the DoA sensors are Ultra-Short Baseline (USBL) devices moored in fixed positions on the sea bottom of the operational area. Measurements obtained by these devices are referred to a local frame. In order to express them in a global frame, an accurate estimation of devices pose (position and attitude) is necessary. Direct measurement of the pose is usually not easy as the USBL devices are typically deployed by hand from a Rigid Hull Inflatable Boat (RHIB). Attitude may be estimated by an integrated Attitude and Heading Reference System (AHRS) but may be affected by unpredictable magnetic disturbances. The calibration procedure aims at determining the pose of the involved USBL devices exploiting acoustic measurements collected when the AUV is on the surface and the GPS signal is available. It has a twofold goal: on one hand, the global-frame measurement errors due to devices pose error estimation are minimised; on the other hand statistics on the expected tracking error, for the particular configuration, are derived to characterise the future identification process
Infection by high-risk human papillomaviruses, epithelial-to-mesenchymal transition and squamous pre-malignant or malignant lesions of the uterine cervix: a series of chained events?
Full text link: Wound healing requires static epithelial cells to gradually assume a mobile phenotype through a multi-step process termed epithelial-to-mesenchymal transition (EMT). Although it is inherently transient and reversible, EMT perdures and is abnormally activated when the epithelium is chronically exposed to pathogens: this event deeply alters the tissue and eventually contributes to the development of diseases. Among the many of them is uterine cervical squamous cell carcinoma (SCC), the most frequent malignancy of the female genital system. SCC, whose onset is associated with the persistent infection of the uterine cervix by high-risk human papillomaviruses (HR-HPVs), often relapses and/or metastasizes, being resistant to conventional chemo- or radiotherapy. Given that these fearsome clinical features may stem, at least in part, from the exacerbated and long-lasting EMT occurring in the HPV-infected cervix; here we have reviewed published studies concerning the impact that HPV oncoproteins, cellular tumor suppressors, regulators of gene expression, inflammatory cytokines or growth factors, and the interactions among these effectors have on EMT induction and cervical carcinogenesis. It is predictable and desirable that a broader comprehension of the role that EMT inducers play in SCC pathogenesis will provide indications to flourish new strategies directed against this aggressive tumor
Simultaneous detection of reverse transcriptase and high molecular weight RNA in tissue of patients with Hodgkin's disease and patients with leukemia.
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Basic fibroblast growth factor modifies the interactions between endothelial cells/fibronectin: Implications for progression of AIDS- associated Kaposi's sarcoma
No full textKaposi's sarcoma (KS) is an angioproliferative disease frequently arising in HIV-1 infected individuals (AIDS-KS). Previous studies indicated that cells derived from AIDS-KS lesions (AIDS-KS cells) produce the angiogenic basic fibroblast growth factor (bFGF) and release it in a biologically active form. Here we show that this extracellular bFGF increases in endothelial cells the expression of fibronectin (FN)-degrading proteases, such as stromelysin-1, stromelysin-3 and collagenase IV, and of the FN- binding integrin α5β1. Consequently, bFGF produced by AIDS-KS cells improves the capability of endothelial cells to migrate toward FN digested and cleaved from blood vessel basement membrane and perivascular stroma by proteases. These results suggest a mechanism for two phenomena that characterize AIDS-KS lesions and that are fundamental for its progression: the invasivity of endothelial cells and the abnormal angiogenesis
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