1,721,012 research outputs found
Antiplasmodial triterpenoids from the fruits of neem, Azadirachta indica.
Full text linkJ Nat Prod. 2010 Aug 27;73(8):1448-52.
Antiplasmodial triterpenoids from the fruits of neem, Azadirachta indica.
Chianese G, Yerbanga SR, Lucantoni L, Habluetzel A, Basilico N, Taramelli D, Fattorusso E, Taglialatela-Scafati O.
Abstract
Eight known and two new triterpenoid derivatives, neemfruitins A (9) and B (10), have been isolated from the fruits of neem, Azadirachta indica, a traditional antimalarial plant used by Asian and African populations. In vitro antiplasmodial tests evidenced a significant activity of the known gedunin and azadirone and the new neemfruitin A and provided useful information about the structure-antimalarial activity relationships in the limonoid class
An enhanced approach for implementing risk-based maintenance in a total productive maintenance perspective
No full textThis paper discusses how to integrate Risk-Based Maintenance (RBM) methods into the Total Productive Maintenance (TPM) approach. The research approach outlined in this study is based on the description of a working procedure that learns from historical data and plans not only predictive but also proactive maintenance activities. Many researchers analysed the combined effects of different maintenance programs. However, topics such as RBM and TPM are generally analysed separately. This study investigates the practices of the two programs simultaneously because after successfully implementing RBM, TPM is needed for a correct equipment condition monitoring, maintenance improvement and planning too. In particular, the development of a single empirical framework can be useful as guidelines for diagnostics, fault prediction, and finally analysis in terms of losses and maintenance performance trends
Learning-based algorithm for fault prediction combining different data mining techniques: A real case study
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Data-driven decision support system for managing item allocation in an ASRS: A framework development and a case study
Full text linkWhen dealing with Automated Storage and Retrieval Systems (ASRS), the allocation of items to the most convenient storage location depends on the vast amount of data produced internally (e.g., Enterprise Resource Planning, Manufacturing Enterprise Systems) and externally (e.g. Supply Chain Management). Moreover, a proper item allocation in the warehouse has a strong influence on the warehouse saturation levels and picking times. In this perspective, the present work proposes the application of data-driven algorithms for managing items in an Automated Storage and Retrieval System (ASRS) in order to reduce the picking times and storage space. Specifically, a four-layer framework is adopted for collecting data produced by different information sources and analyzing them through a data-driven approach. The analytics layer is performed by combining the Association Rule Mining (ARM) technique, to investigate the network of influences among data collected, and a simulation approach for assessing the feasibility of the proposed implementation. The Association Rule Mining allows company managers to identify the components that should be located on the same tray in the ASRS, defining the couples of items frequently picked together in order to reduce the total picking time. The proposed approach is applied to the case study of a shoe manufacturing company to explain the research approach and show how the implementation of the data-driven methodology can provide valuable support in defining item allocation and picking rules. The proposed Association Rule Mining method is new in this context and it has shown a positive impact in comparison to traditional solutions of warehouse management, providing a complete overview of the items’ interactions and identifying communities of items that define local and global patterns and locate influential entities
Big data-driven framework for viral churn prevention: A case study
No full textThe application of churn prevention represents an important step for mobile communication companies aiming at increasing customer loyalty. In a machine learning perspective, Customer Value Management departments require automated methods and processes to create marketing campaigns able to identify the most appropriate churn prevention approach. Moving towards a big data-driven environment, a deeper understanding of data provided by churn processes and client operations is needed. In this context, a procedure aiming at reducing the number of churners by planning a customized marketing campaign is deployed through a data-driven approach. Decision Tree methodology is applied to drow up a list of clients with churn propensity: in this way, customer analysis is detailed, as well as the development of a marketing campaign, integrating the individual churn model with viral churn perspective. The first step of the proposed procedure requires the evaluation of churn probability for each customer, based on the influence of his social links. Then, the customer profiling is performed considering (a) individual variables, (b) variables describing customer-company interactions, (c) external variables. The main contribution of this work is the development of a versatile procedure for viral churn prevention, applying Decision Tree techniques in the telecommunication sector, and integrating a direct campaign from the Customer Value Management marketing department to each customer with significant churn risk. A case study of a mobile communication company is also presented to explain the proposed procedure, as well as to analyze its real performance and results
Effects of a neem extract on blood feeding, oviposition and oocyteultrastructure in Anopheles stephensi Liston (Diptera: Culicidae)
Full text linkSecondary metabolites of the neem tree (Azadirachta indica A. Juss., Meliaceae) exhibit a wide range of biological activities in insects. However, few studies have addressed the effects of neem extracts or compounds in arthropods of medical importance. In this study, a laboratory strain of Anopheles stephensi was used to assess the effects of a commercial formulation (Neem Azal® (NA)), containing azadirachtin A at 34%, on blood feeding, oviposition and oocyte ultrastructure. Oral administration of Neem Azal® to A. stephensi females through artificial blood meals did impair blood intake and oviposition in a concentration dependent manner. Similar results were obtained on females, which had consumed Neem Azal® in sucrose solution before taking a blood meal of plain blood. Neem treated females displayed a delay in oocyte development in both the phase of vitellogenesis and the phase of choriogenesis. The ultrastructural studies on ovaries from Neem Azal® treated females revealed distinct structural modifications indicative of: (i) a complete block of oogenesis, (ii) impairment of vitellogenesis and vitelline envelope formation, (iii) a severe degeneration of follicle cells. In agreement with results obtained in other insects, this study indicates that Neem Azal® impairs hormone control of oogenesis and exerts a cytotoxic effect on both follicular cells and oocytes of the Asian malaria vector A. stephensi. © 2006 Elsevier Ltd. All rights reserved
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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