Gestion des connaissances : préambule à un portrait

Pour des raisons de performance, innovation ou compétitivité, les connaissances sont devenues une ressource de première importance dans les organisations de l’économie du savoir. Gérer les connaissances explicites et tacites représente une stratégie ayant ses propres concepts, méthodes, outils, qui attirent l’attention des spécialistes. En appliquant une analyse à un corpus d’articles scientifiques, cette étude se propose d’identifier les domaines traitant ou mettant en application la gestion des connaissances, afin de dresser un inventaire de ses champs d’étude et/ou d’application et contribuer ainsi à une meilleure compréhension de ses bénéfices. Ce texte présente des résultats préliminaires : douze domaines d’étude identifiés comme abordant la gestion des connaissances, à comparer aux résultats de la deuxième étape de la recherche (en cours), pour finalement élaborer un portrait de la gestion des connaissances et des aires d’études reliées.By reason of performance, innovation or competitiveness, knowledge has become an important resource for organisations in the knowledge economy. Managing the explicit and the tacit knowledge represents a strategy with its own concepts, methods, and tools, which draws the attention of specialists. Through an analysis on a corpus of scientific articles, this study aims to identify those fields related to, or utilizing knowledge management. The objective of this task is to draft an inventory of study fields and of the various applications of managing knowledge, thus to contribute to a better understanding of its benefits. This paper sums up the preliminary results of this two-part analysis : twelve fields have been identified as bearing an interest in knowledge management; they will be compared to the results obtained in the second part of the analysis (in progress), in order to work out a portrait of knowledge management and its related study areas

Identification of Cellular Host Factors That Associate With LINE-1 ORF1p and the Effect of the Zinc Finger Antiviral Protein Zap on LINE-1 Retrotransposition.

Long INterspersed Element-1 (LINE-1 or L1) is the only active autonomous retrotransposon in the human genome. The human genome contains over 500,000 L1 sequences, which account for approximately 17% of human DNA. L1 sequences mobilize throughout the human genome by a copy-and-paste mechanism known as retrotransposition. Most genomic L1 sequences are incapable of mobility (i.e., retrotransposition) because they are either 5'-truncated, internally rearranged, and/or mutated; however, it is estimated that each human cell contains at least 80-100 intact L1 sequences that are retrotransposition capable. L1 retrotransposition is inherently mutagenic and on occasion can disrupt gene expression leading to diseases such as hemophilia A and cancer. Due to the mutagenic potential of L1 retrotransposition, it thus stands to reason that the host cell has evolved mechanisms to protect the cell from unabated retrotransposition. In this thesis I identified cellular host factors that associate with the first L1 open reading frame protein, ORF1p. I demonstrate that the zinc finger antiviral protein ZAP associates with L1 ORF1p and inhibits human L1 and Alu retrotransposition as well as the retrotransposition of LINE elements from mice and zebrafish. Molecular genetic, biochemical, and fluorescence microscopy data suggest that ZAP interacts with L1 RNA and reduces the expression of full-length L1 RNA and the L1-encoded proteins, thereby providing mechanistic insight into how ZAP may restrict retrotransposition. In addition to ZAP, I show that the ORF1p-associated cellular host factors MOV10, hnRNPL, and PAR-4 also inhibit L1 retrotransposition. Mechanistic data suggest that ZAP, MOV10, hnRNPL, and PAR-4 restrict L1 retrotransposition by distinct mechanisms, suggesting that each of these cellular host factors may target different post-transcriptional steps in the L1 retrotransposition cycle. Importantly, ZAP and MOV10 were first characterized as antiviral proteins due to their ability to suppress retroviral activity. Notably, several other host cell antiviral factors such as APOBEC3 proteins, TREX1, SAMHD1 and RNase L have recently been demonstrated to inhibit L1 retrotransposition. Thus, these data suggest that ZAP, MOV10 and perhaps other ORF1p-associated cellular host factors initially may have evolved to combat L1 and other endogenous retrotransposons and subsequently were co-opted as viral restriction factors.PHDCellular and Molecular BiologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/113417/1/jmoldova_1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/113417/2/jmoldova_2.pd

The impact of treewidth on ASP grounding and solving of Answer Set Programs

Peer reviewe

iPSC-Derived Vascular Cell Spheroids as Building Blocks for Scaffold-Free Biofabrication

Recently a protocol is established to obtain large quantities of human induced pluripotent stem cells (iPSC)-derived endothelial progenitors, called endothelial colony forming cells (ECFC), and of candidate smooth-muscle forming cells (SMFC). Here, the suitability for assembling in spheroids, and in larger 3D cell constructs is tested. iPSC-derived ECFC and SMFC are labeled with tdTomato and eGFP, respectively. Spheroids are formed in ultra-low adhesive wells, and their dynamic proprieties are studied by time-lapse microscopy, or by confocal microscopy. Spheroids are also tested for fusion ability either in the wells, or assembled on the Regenova 3D bioprinter which laces them in stainless steel micro-needles (the “Kenzan” method). It is found that both ECFC and SMFC formed spheroids in about 24 h. Fluorescence monitoring indicated a continuous compaction of ECFC spheroids, but stabilization in those prepared from SMFC. In mixed spheroids, the cell distribution changed continuously, with ECFC relocating to the core, and showing pre-vascular organization. All spheroids have the ability of in-well fusion, but only those containing SMFC are robust enough to sustain assembling in tubular structures. In these constructs a layered distribution of alpha smooth muscle actin-positive cells and extracellular matrix deposition is found. In conclusion, iPSC-derived vascular cell spheroids represent a promising new cellular material for scaffold-free biofabrication

Telepathology a Useful Method in the Diagnosis Digestive Biopsies with Rare Entities. Case Presentation of a Collagenous Gastritis.

Introduction/ Background Collagenous gastritis is a rare entity in current surgical pathology practice. Since the introduction of the term until present, only small series and isolated cases have been reported, generally by high-specialized centers in gastrointestinal pathology. In current practice, the diagnosis of this unusual affection is based on clinical data corroborated with endoscopic and pathological findings. Due to the small number of cases the diagnostic criteria are partly taken from microscopic colitis diagnosis. Thus, it is considered that the association of the appropriate clinical context (stomach pain, watery diarrhea, endoscopic nodular appearance) and histological gastritis changes with collagen deposition of dense material with a 10um minimum variable thickness that comprises capillaries and inflammatory elements. The technical advantage of a digital slide scanner is allowing access to an experienced pathologist in digestive pathology’s opinion and conducting precision measurement. Aims Our presentation brings to attention of pathologist community a rarely diagnosed entity and the advantages of tele-pathology in timely accessing an expert opinion and performing accurate measurements. Methods We received gastric biopsy samples endoscopically taken from a 56-year female who complained of transit disorders, vomiting, epigastric pain that did not improve after IPP treatment. On endoscopy exam a nonspecific aspect with discrete erythema and vaguely nodular appearance of the gastric mucosae was noted. The specimens were paraffin embedded, and serial sections were stained HE, AB-PAS and MGG. The obtained slides were fully scanned and a gastrointestinal pathology expert advice was requested. Subsequently, a Mason’s Trichrome stain and tenascin immunohistochemistry test were performed. The examined section showed gastric mucosal epithelium with scarce intraepithelial lymphocytes (5-6 lymphocytes/100 cells). The surface epithelium had the tendency to roll away from the variable thickened stroma. The glandular architecture and chorion were modified by a nonspecific inflammatory infiltrate. A diagnose of chronic inactive gastritis with intestinal metaplasia areas was propose, and an expert opinion was requested. Digitally scanned sections using the Leica II Aperio slide scanner were taken. Examination of slides was made using the Imagescope12.2 Leica. Micrometeric measurements of the hyaline material varied between 9.5-51um. The review of glass slides on traditional optical microscope was made confirming the diagnosis. Results Collagenous gastritis remains an underestimated condition due to its low incidence and lack of expertise in the field. Hence telepathology becomes a useful tool for requesting a second opinion and precisions measurements

Prilagodba usnih organa kod nekih podzemnih holevina (Cholevinae) (Coleoptera, Leiodidae)

Cholevinae are a group of beetles with many cave representatives that are mainly detritivorous or saprophagous. Some species show modifications of the mouthparts on account of their dietary niche, being adapted to a semi-aquatic way of life, or on account of the degree of adaptation to the life in caves. Differences are obvious also among the genera, and cave species that are at the same level of adaptation. The main modifications concern the shape and structure of the different parts, as well as their length and the disposal of hairs, bristles and setae. The adaptation to an aquatic dietary niche has modified the mandibles, which acquired a spoon-like form to bring water near the mouth, the lacinia taking on the role of stirring and the galea of filtering the organic particles with its fine and very dense hairs. The apparent uniformity of the subterranean environmental conditions and of the trophic resources, together with the scarcity of the latter, might mistakenly lead to the conclusion of a one-way evolution for the underground colonizers. The observed differences between the mouthparts of the studied species can be good material for taxonomists, who can include some of these features in their studies, often difficult due to the homogenous morphology of many inhabitants of the underground. As a contribution to the comparative study of the mouthparts at some representatives of cholevin beetles, we can also highlight the effect of adaptation to cave life on the mouthparts and the evidence of a divergent evolution in a relatively constant environment in terms of climate and food input.Holevine su skupina kornjaša s mnogo podzemnih predstavnika koji su pretežno detritivorni ili saprofagni. Neke vrste pokazuju modifikacije usnih organa zbog svoje prehrambene niše, prilagođavajući se poluakvatičkom načinu života, ili zbog stupnja adaptacije na život u špilji. Razlike su očite i među rodovima i špiljskim vrstama koje su na istom stupnju adaptacije. Glavne modifikacije tiču se oblika i strukture različitih dijelova, kao i njihove duljine, i rasporeda dlaka, čekinja i seta. Prilagodba na akvatičku prehrambenu nišu modificirala je čeljusti, koje su dobile oblik žlice kojom se voda prinosi ustima; lacinia preuzima ulogu miješanja, a galea filtriranja organskih čestica svojim finim i vrlo gustim dlačicama. Očita jednoličnost uvjeta u podzemnom okolišu, te izvora hrane, zajedno s njenom rijetkošću, mogu pogrešno upućivati na jednosmjernu evoluciju stanovnika podzemlja. Uočene razlike između usnih organa proučavanih vrsta mogu biti dobar materijal za taksonomiste koji neke od tih osobina mogu uključiti u svoj rad, obično težak zbog homogene morfologije mnogih stanovnika podzemlja. Kao doprinos komparativnoj studiji usnih organa nekih predstavnika holevina, na temelju usnih organa naglašavamo efekt prilagodbe na špiljski život te dokaz divergentne evolucije u relativno konstantnom okolišu, u smislu klime i dotoka hrane

Nectar formation and floral nectary anatomy of Anigozanthos flavidus: a combined magnetic resonance imaging and spectroscopy study

Metabolic processes underlying the formation of floral nectar carbohydrates, especially the generation of the proportions of fructose, glucose, and sucrose, are important for understanding ecological plant–pollinator interactions. The ratio of sucrose-derived hexoses, fructose and glucose, in the floral nectar of Anigozanthos flavidus (Haemodoraceae) was observed to be different from 1:1, which cannot be explained by the simple action of invertases. Various NMR techniques were used to investigate how such an unbalanced ratio of the two nectar hexoses can be formed. High-resolution 13C NMR spectroscopy in solution was used to determine the proportion of carbohydrates in vascular bundles of excised inflorescences fed with 13C-labelled carbohydrates. These experiments verified that feeding did not affect the metabolic processes involved in nectar formation. In vivo magnetic resonance imaging (e.g. cyclic J cross-polarization) was used to detect carbohydrates in vascular bundles and 1H spin echo imaging non-invasively displayed the architecture of tepal nectaries and showed how they are connected to the vascular bundles. A model of the carbohydrate metabolism involved in forming A. flavidus floral nectar was established. Sucrose from the vascular bundles is not directly secreted into the lumen of the nectary but, either before or after invertase-catalysed hydrolyses, taken up by nectary cells and cycled at least partly through glycolysis, gluconeogenesis, and the pentose phosphate pathway. Secretion of the two hexoses in the cytosolic proportion could elegantly explain the observed fructose:glucose ratio of the nectar