Μη-μεταστατικό ειλεακό λειομυοσάρκωμα σε ενήλικο περιστέρι (<i>Columba livia</i>)

Intestinal smooth muscle neoplasms are rarely reported in avian species. An aged male pouter pigeon (Columba livia) had anorexia, somnolence, progressive emaciation and yellowish diarrhea of four days' duration and died despite antibiotic and antiparasitic treatment. At necropsy, the ileum bore a whitish, nodular, 0.8 cm in diameter mass severely narrowing the lumen. Histopathologically, the ileal mass was a well-demarcated, expansile neoplasm severely expanding the tunica muscularis and invading the mucosa. The neoplasm was composed of densely packed spindle cells with elongated nuclei arranged in broad interlacing bundles, and showing mild anisocytosis and anisokaryosis. Immunohistochemically, the neoplasm was positive for desmin and smooth muscle actin, and negative for cytokeratin, and c-kit. The gross, histopathologic and immunohistochemical findings provided the diagnosis of ileal leiomyosarcoma. This is the first report of an ileal leiomyosarcoma in Columbiformes and one of few intestinal smooth muscle neoplasms described in birds.Νεοπλάσματα που προέρχονται από το μυϊκό χιτώνα του εντέρου αναφέρονται σπάνια στα πτηνά. Ενα ενήλικο αρσενικό περιστέρι “pouter” (Columba livia) παρουσιάστηκε με ανορεξία, υπνηλία, προοδευτική απίσχναση και κίτρινη διάρροια διάρκειας 4 ημερών και απεβίωσε παρά τη χορήγηση αντιβιοτικών και αντιπαρασιτικής αγωγής. Νεκροτομικά, ο ειλεός έφερε μία λευκωπή, οζώδη μάζα διαμέτρου 0.8 εκ. η οποία προκαλούσε σοβαρού βαθμού στένωση του αυλού. Ιστοπαθολογικά, η μάζα αποτελείτο από ένα καλά περιγεγραμμένο νεόπλασμα που αφορούσε και επέκτεινε το μυϊκό χιτώνα και διείσδυε στο βλεννογόνο. Το νεόπλασμα αποτελείτο από κυτταρικά εμβριθή πληθυσμό ατρακτοειδών κυττάρων διατεταγμένων σε ευρείες αλληλοπλεκόμενες δεσμίδες, με επιμήκεις πυρήνες και ήπια ανισοκυττάρωση και ανισοπυρήνωση. Ανοσοϊστοχημικά, το νεόπλασμα ήταν θετικό στη δεσμίνη και ακτίνη του λείου μυϊκού ιστού και αρνητικό στην κυτταροκερατίνη και c-kit. Με βάση τα μακροσκοπικά, ιστοπαθολογικά και ανοσοϊστοχημικά ευρήματα, ετέθη η διάγνωση του ειλεακού λειομυοσαρκώματος. Η παρούσα είναι η πρώτη αναφορά ειλεακού λειομυοσαρκώματος σε Columbiformes και μία από τις λίγες αναφορές εντερικών νεοπλασμάτων του λείου μυϊκού χιτώνα σε πτηνά.Facultad de Ciencias Veterinaria

A general framework for searching in distributed data repositories

This paper proposes a general framework for searching large distributed repositories. Examples of such repositories include sites with music/video content, distributed digital libraries, distributed caching systems, etc. The framework is based on the concept of neighborhood; each client keeps a list of the most beneficial sites according to past experience, which are visited first when the client searches for some particular content. Exploration methods continuously update the neighborhoods in order to follow changes in access patterns. Depending on the application, several variations of search and exploration processes are proposed. Experimental evaluation demonstrates the benefits of the framework in different scenarios.published_or_final_versio

Μη-μεταστατικό ειλεακό λειομυοσάρκωμα σε ενήλικο περιστέρι (<i>Columba livia</i>)

Intestinal smooth muscle neoplasms are rarely reported in avian species. An aged male pouter pigeon (Columba livia) had anorexia, somnolence, progressive emaciation and yellowish diarrhea of four days' duration and died despite antibiotic and antiparasitic treatment. At necropsy, the ileum bore a whitish, nodular, 0.8 cm in diameter mass severely narrowing the lumen. Histopathologically, the ileal mass was a well-demarcated, expansile neoplasm severely expanding the tunica muscularis and invading the mucosa. The neoplasm was composed of densely packed spindle cells with elongated nuclei arranged in broad interlacing bundles, and showing mild anisocytosis and anisokaryosis. Immunohistochemically, the neoplasm was positive for desmin and smooth muscle actin, and negative for cytokeratin, and c-kit. The gross, histopathologic and immunohistochemical findings provided the diagnosis of ileal leiomyosarcoma. This is the first report of an ileal leiomyosarcoma in Columbiformes and one of few intestinal smooth muscle neoplasms described in birds.Νεοπλάσματα που προέρχονται από το μυϊκό χιτώνα του εντέρου αναφέρονται σπάνια στα πτηνά. Ενα ενήλικο αρσενικό περιστέρι “pouter” (Columba livia) παρουσιάστηκε με ανορεξία, υπνηλία, προοδευτική απίσχναση και κίτρινη διάρροια διάρκειας 4 ημερών και απεβίωσε παρά τη χορήγηση αντιβιοτικών και αντιπαρασιτικής αγωγής. Νεκροτομικά, ο ειλεός έφερε μία λευκωπή, οζώδη μάζα διαμέτρου 0.8 εκ. η οποία προκαλούσε σοβαρού βαθμού στένωση του αυλού. Ιστοπαθολογικά, η μάζα αποτελείτο από ένα καλά περιγεγραμμένο νεόπλασμα που αφορούσε και επέκτεινε το μυϊκό χιτώνα και διείσδυε στο βλεννογόνο. Το νεόπλασμα αποτελείτο από κυτταρικά εμβριθή πληθυσμό ατρακτοειδών κυττάρων διατεταγμένων σε ευρείες αλληλοπλεκόμενες δεσμίδες, με επιμήκεις πυρήνες και ήπια ανισοκυττάρωση και ανισοπυρήνωση. Ανοσοϊστοχημικά, το νεόπλασμα ήταν θετικό στη δεσμίνη και ακτίνη του λείου μυϊκού ιστού και αρνητικό στην κυτταροκερατίνη και c-kit. Με βάση τα μακροσκοπικά, ιστοπαθολογικά και ανοσοϊστοχημικά ευρήματα, ετέθη η διάγνωση του ειλεακού λειομυοσαρκώματος. Η παρούσα είναι η πρώτη αναφορά ειλεακού λειομυοσαρκώματος σε Columbiformes και μία από τις λίγες αναφορές εντερικών νεοπλασμάτων του λείου μυϊκού χιτώνα σε πτηνά.Facultad de Ciencias Veterinaria

Canonical variable analysis and long short-term memory for fault diagnosis and performance estimation of a centrifugal compressor

© 2017 Centrifugal compressors are widely used for gas lift, re-injection and transport in the oil and gas industry. Critical compressors that compress flammable gases and operate at high speeds are prioritized on maintenance lists to minimize safety risks and operational downtime hazards. Identifying incipient faults and predicting fault evolution for centrifugal compressors could improve plant safety and efficiency and reduce maintenance and operation costs. This study proposes a dynamic process monitoring method based on canonical variable analysis (CVA) and long short-term memory (LSTM). CVA was used to perform fault detection and identification based on the abnormalities in the canonical state and the residual space. In addition, CVA combined with LSTM was used to estimate the behavior of a system after the occurrence of a fault using data captured from the early stages of deterioration. The approach was evaluated using process data obtained from an operational industrial centrifugal compressor. The results show that the proposed method can effectively detect process abnormalities and perform multi-step-ahead prediction of the system's behavior after the appearance of a fault

Potential effect of Nigella sativa against Diethylnitrosamine-induced hepatocarcinogenesis in rats

Objective of the investigation was the study of potential protective effects of the watery extract of Nigella sativa against diethylnitrosamine induced hepatocarcinogenesis in rats. N. sativa was administered to rats for protection against diethylnitrosamine-induced hepatocarcinogenesis. It was administered prior to, simultaneously with or after injection of diethylnitrosamine. Five groups of Wister rats were used. Group A was administered diethylnitrosamine and N. sativa simultaneously, group B was administered only diethylnitrosamine and group C received only N. sativa. These three groups were maintained for up to eight weeks. Group D received N. sativa six weeks after administration ofdiethylnitrosamine,while group E (“protective group”) received N. sativa on day 1 and diethylnitrosamine six weeks later. These two groups were maintained for up to 12 weeks. All rats were subjected to partial hepatectomy to enhance carcinogenesis. P-isoform of glutathione s transferase (GST-P) was detected in the cytoplasm and nuclei of hepatocytes. The number of GST-P positive foci was significantly smaller in test groups (A, D, E), particularly in groups A and E, when compared with to those in group B, indicating that N. sativa has protective effects against diethylnitrosamine induced liver cancer in rats, even in the very early stages of hepatocarcinogenesis

Dealing with missing data for prognostic purposes

© 2016 IEEE. Centrifugal compressors are considered one of the most critical components in oil industry, making the minimisation of their downtime and the maximisation of their availability a major target. Maintenance is thought to be a key aspect towards achieving this goal, leading to various maintenance schemes being proposed over the years. Condition based maintenance and prognostics and health management (CBM/PHM), which is relying on the concepts of diagnostics and prognostics, has been gaining ground over the last years due to its ability of being able to plan the maintenance schedule in advance. The successful application of this policy is heavily dependent on the quality of data used and a major issue affecting it, is that of missing data. Missing data's presence may compromise the information contained within a set, thus having a significant effect on the conclusions that can be drawn from the data, as there might be bias or misleading results. Consequently, it is important to address this matter. A number of methodologies to recover the data, called imputation techniques, have been proposed. This paper reviews the most widely used techniques and presents a case study with the use of actual industrial centrifugal compressor data, in order to identify the most suitable ones

Reciprocating compressor prognostics

Reciprocating compressors are vital components in oil and gas industry though their maintenance cost can be high. The valves are considered the most frequent failing part accounting for almost half the maintenance cost. Condition Based Maintenance and Prognostics and Health Management which is based on diagnostics and prognostics principles can assist towards reducing cost and downtime while increasing safety and availability by offering a proactive means for scheduling maintenance. Although diagnostics is an established field for reciprocating compressors, there is limited information regarding prognostics, particularly given the nature of failures can be instantaneous. This paper compares several prognostics methods (multiple liner regression, polynomial regression, K-Nearest Neighbours Regression (KNNR)) using valve failure data from an operating industrial compressor. Moreover, a variation about Remaining Useful Life (RUL) estimation process based on KNNR is proposed along with an ensemble method combining the output of all aforementioned algorithms. In conclusion it is showed that even when RUL is relatively short given the instantaneous failure mode, good estimates are feasible using the proposed methods

Reciprocating compressor prognostics of an instantaneous failure mode utilising temperature only measurements

Reciprocating compressors are critical components in the oil and gas sector, though their maintenance cost is known to be relatively high. Compressor valves are the weakest component, being the most frequent failure mode, accounting for almost half the maintenance cost. One of the major targets in industry is minimisation of downtime and cost, while maximising availability and safety of a machine, with maintenance considered a key aspect in achieving this objective. The concept of Condition Based Maintenance and Prognostics and Health Management (CBM/PHM) which is founded on the diagnostics and prognostics principles, is a step towards this direction as it offers a proactive means for scheduling maintenance. Despite the fact that diagnostics is an established area for reciprocating compressors, to date there is limited information in the open literature regarding prognostics, especially given the nature of failures can be instantaneous. This work presents an analysis of prognostic performance of several methods (multiple linear regression, polynomial regression, K-Nearest Neighbours Regression (KNNR)), in relation to their accuracy and variability, using actual temperature only valve failure data, an instantaneous failure mode, from an operating industrial compressor. Furthermore, a variation for Remaining Useful Life (RUL) estimation based on KNNR, along with an ensemble technique merging the results of all aforementioned methods are proposed. Prior to analysis, principal components analysis and statistical process control were employed to create !! and ! metrics, which were proposed to be used as health indicators reflecting degradation process of the valve failure mode and are proposed to be used for direct RUL estimation for the first time. Results demonstrated that even when RUL is relatively short due to instantaneous nature of failure mode, it is feasible to perform good RUL estimates using the proposed techniques