372 research outputs found

    Molecular biology meets Logic : context-sensitiveness in focus

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    Some real life processes, including molecular ones, are context-sensitive, in the sense that their outcome depends on side conditions that are most of the times difficult, or impossible, to express fully in advance. In this paper, we survey and discuss a logical account of context-sensitiveness in molecular processes, based on a kind of non-classical logic. This account also allows us to revisit the relationship between logic and philosophy of science (and philosophy of biology, in particular)

    An EST database from saffron stigmas

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    BACKGROUND: Saffron (Crocus sativus L., Iridaceae) flowers have been used as a spice and medicinal plant ever since the Greek-Minoan civilization. The edible part - the stigmas - are commonly considered the most expensive spice in the world and are the site of a peculiar secondary metabolism, responsible for the characteristic color and flavor of saffron. RESULTS: We produced 6,603 high quality Expressed Sequence Tags (ESTs) from a saffron stigma cDNA library. This collection is accessible and searchable through the Saffron Genes database http://www.saffrongenes.org. The ESTs have been grouped into 1,893 Clusters, each corresponding to a different expressed gene, and annotated. The complete set of raw EST sequences, as well as of their electopherograms, are maintained in the database, allowing users to investigate sequence qualities and EST structural features (vector contamination, repeat regions). The saffron stigma transcriptome contains a series of interesting sequences (putative sex determination genes, lipid and carotenoid metabolism enzymes, transcription factors). CONCLUSION: The Saffron Genes database represents the first reference collection for the genomics of Iridaceae, for the molecular biology of stigma biogenesis, as well as for the metabolic pathways underlying saffron secondary metabolism

    Cavitating Pump Rotordynamic Test Facility at ALTA S.p.A.: Upgraded Capabilities of a Unique Test Rig

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    The paper illustrates the upgrades recently introduced in Alta’s Cavitating Pump Rotordynamic Test Facility in order to extend its experimental capabilities, with special reference to the addition of an auxiliary pump for testing of turbopump inducers over a wider range of flow coefficients, and the set-up of an original apparatus specifically designed for the characterization of the dynamic transfer matrices of cavitating inducers and turbopumps. Examples are presented of the improved capabilities of the facility

    A Dual-Stream architecture based on Neural Turing Machine and Attention for the Remaining Useful Life Estimation problem

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    Estimating in a reliable way the Remaining Useful Life (RUL) of a mechanical component is a fundamental task in the field of Prognostics and Health Management (PHM). In recent years a greater availability of high quality sensors and easiness of data gathering gave rise to data-driven models based on deep learning for this task, which has recently seen the introduction of \u201cdual-stream\u201d architectures. In this paper we propose a dual-stream architecture to address the RUL estimation problem through the exploitation of a Neural Turing Machine (NTM) and a Multi-Head Attention (MHA) mechanism. The NTM is a content-based memory addressing system which gives each of the streams the ability to access to and interact with the memory and acts as a fusion technique. The MHA is an attention mechanism added as a mean for our architecture to identify the existing relations between different sensor data in order to reveal hidden patterns among them. To evaluate the performance of our model, we considered the C-MAPSS dataset, a benchmark dataset published by NASA consisting of several time series related to the life of turbofan engines. We show that our approach achieves the best prediction score (which measures the safety of the predictions) in the available literature on two of the C-MAPSS subdatasets

    Rotordynamic Forces on a Three Bladed Inducer under Forced Whirl Motion Operating at Different Conditions

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    The paper illustrates the main results of an experimental campaign conducted in the CPRTF (Cavitating Pump Rotordynamic Test Facility) at ALTA S.p.A., aimed at characterizing the rotordynamic forces acting on a whirling three-bladed, tapered-hub, variable-pitch inducer, named DAPROT3. The forces acting on the impeller have been measured by means of a rotating dynamometer mounted just behind the inducer. The roles of the imposed whirl motion of the rotor, flow coefficient, cavitation number and liquid temperature have been investigated. The results have been obtained by means of a recent experimental technique, consisting in measuring the continuous spectra of the rotordynamic forces as functions of the whirl excitation frequency. This technique allows for extrapolating valuable information from the experiments by more accurately and rapidly characterizing the spectral behavior of these forces than can be obtained from a limited number of point experiments conducted at constant whirl frequency. Therefore, it is useful to better capture the complexity of the rotordynamic forces and assess their consequences on the stability of axial inducers

    Zsyntax: A Formal Language for Molecular Biology with Projected Applications in Text Mining and Biological Prediction

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    We propose a formal language that allows for transposing biological information precisely and rigorously into machine-readable information. This language, which we call Zsyntax (where Z stands for the Greek word ζωή, life), is grounded on a particular type of non-classical logic, and it can be used to write algorithms and computer programs. We present it as a first step towards a comprehensive formal language for molecular biology in which any biological process can be written and analyzed as a sort of logical “deduction”. Moreover, we illustrate the potential value of this language, both in the field of text mining and in that of biological prediction

    Prognostic factors influencing infectious complications after cytoreductive surgery and HIPEC. Results from a tertiary referral center

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    Background. Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) showed promising results in selected patients. High morbidity restrains its wide application. The aim of this study was to report postoperative infectious complications and investigate possible correlations with preoperative nutritional status and other prognostic factors in patients with peritoneal metastases treated with CRS and HIPEC. Methods. For the study we reviewed the clinical records of all patients with peritoneal metastases from different primary cancers and treated by CRS and HIPEC in our Institution from November 2000 to December 2017. Patients were divided according to their nutritional status (SGA) in group A (well-nourished), B/C (mild or severely malnourished). Possible statistical correlations between risk factors and postoperative complications rates have been investigated by univariate and multivariate analysis. Results. Two hundred patients were selected and underwent CRS and HIPEC during the study period. Postoperative complications occurred in 44% of the patients, 35.3% in SGA-A patients and 53% in SGA-B /C patients. Cause of complications was infective in 42, non-infective in 37 and HIPEC related in 9 patients. Infectious complications occurred more frequently in SGA-B /C patients (32.6% vs. 9.8% of SGA-A patients). The most frequent sites of infection were Surgical Site Infections (SSI, 35.7%) and Central Line Associated BloodStream Infections (CLABSI, 26.2%). The most frequent isolated species was Candida (22.8%). ASA score, blood loss, performance status, PCI, large bowel resection, postoperative serum albumin levels and nutritional status correlated with higher risk for postoperative infectious complications. Conclusions. Malnourished patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy are more prone to post-operative infectious complications and adequate perioperative nutritional support should be considered, including immune-enhancing nutrition. Sequential monitoring of common sites of infection, antifungal prevention of candidiasis, and careful patient selection should be implemented to reduce complications rate

    On the Preliminary Design and Performance Prediction of Centrifugal Turbopumps—Part 2

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    The ideal flow model for the preliminary design and performance prediction of radial turbopumps presented in the companion paper of the present volume (d’Agostino et al., 2017) is here interfaced with the calculation of the boundary layers inside the blade channels and other major forms of flow losses, with the aim of developing an effective tool for rapid parametric optimization of the machine performance and geometry under appropriate design constraints, such as assigned values of the specific speed, flow coefficient and blade solidity. A mixed-flow turbopump, with a six-bladed impeller, a vaneless diffuser, a single-spiral volute and nondimensional performance characteristics similar to those typically used in liquid propellant rocket engine feed systems, has been designed, parametrically optimized and manufactured in accordance with the indications of the present model. The pumping and suction performance of the machine have been determined in a series of tests in the Cavitating Pump Rotordynamic Test Facility (CPRTF). Under fully-wetted flow conditions the measured pumping characteristics of the machine (hydraulic head and efficiency as functions of the flow coefficient) proved to be in excellent agreement with the model predictions, thus successfully confirming the validity of the proposed model as an effective tool for rapid and efficient design of high-performance centrifugal turbopumps
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