325 research outputs found
Assembly of objects with not fully predefined shapes
An assembly problem in a non-deterministic environment, i.e., where parts to be assembled have unknown shape, size and location, is described. The only knowledge used by the robot to perform the assembly operation is given by a connectivity rule and geometrical constraints concerning parts. Once a set of geometrical features of parts has been extracted by a vision system, applying such a rule allows the dtermination of the composition sequence. A suitable sensory apparatus allows the control the whole operation
The Impact of Rural Nebraska Industrial Development on the Migration of Rural Youth
For more than a century Americans have migrated from the rural communities in which they were raised, but by 1970 this process had begun to change. Nebraska, however, has not reflected this change, and Nebraskans have continued to leave non-metropolitan areas in large numbers. By 1976 the State stood alone among seven central and southern plains states in having non-metropolitan population losses (Miller, 1978)
Combining Flexible Queries and Knowledge Anchors to facilitate the exploration of Knowledge Graphs
Semantic web and information extraction technologies are enabling the creation of vast information and knowledge repositories, particularly in the form of knowledge graphs comprising entities and the relationships between them. Users are often unfamiliar with the complex structure and vast content of such graphs. Hence, users need to be assisted by tools that support interactive exploration and flexible querying. In this paper we draw on recent work in flexible querying for graph-structured data and identifying good anchors for knowledge graph exploration in order to demonstrate how users can be supported in incrementally querying, exploring and learning from large complex knowledge graphs. We demonstrate our techniques through a case study in the domain of lifelong learning and career guidance
Development, characterization and application of 3D printed adsorbents for in situ recovery of taxadiene from microbial cultivations
Microbial cell factories are an attractive alternative to produce high-value natural products using sustainable processes. However, product recovery is one of the main challenges to reduce production cost and make these technologies economically interesting. In this work, new resins were formulated to 3D print hydrophobic adsorbents for the recovery of biologics from microbial cultivations. Benzyl methacrylate (BEMA) and butyl methacrylate (BUMA) were selected as functional monomers suitable for the adsorption of hydrophobic compounds. Pore morphology was tailored through the inclusion of pore forming agents (porogens) in the resin. Different porogens and porogen concentrations were evaluated resulting in materials with different porous networks. Sudan 1 and the anticancer drug paclitaxel were employed as model compounds to test the adsorption performance of hydrophobic and terpene molecules onto the developed 3D printed materials. The material with greatest adsorption capacity was obtained using BEMA monomer with 40 % (v/v) porogen (BEMA40). The performance of BEMA40 to recover taxadiene from small-scale (5 mL) Saccharomyces cerevisiae cultivations was tested and compared with commercial Diaion HP-20 beads. Taxadiene titres on BEMA40 (46 ± 2 mg/L) and Diaion HP-20 (54 ± 4 mg/L) were comparable, with no taxadiene detected in the cells and cell-free media, suggesting near 100 % taxadiene partition on the adsorbents. Compared to commercial beads, 3D printed adsorbents can be customized with adjustments in the resin formulation, are well adaptable to diverse bioreactor types, do not clog sampling ports and columns and are easier to handle during post processing. The results of this work demonstrate the potential of 3D printing to fabricate hydrophobic interaction adsorbent materials and their application in the recovery of biological products
Combining flexible queries and knowledge anchors to facilitate the exploration of knowledge graphs
Semantic web and information extraction technologies are enabling the creation of vast information and knowledge repositories, particularly in the form of knowledge graphs comprising entities and the relationships between them. Users are often unfamiliar with the complex structure and vast content of such graphs. Hence, users need to be assisted by tools that support interactive exploration and flexible querying. In this paper we draw on recent work in flexible querying for graph-structured data and identifying good anchors for knowledge graph exploration in order to demonstrate how users can be supported in incrementally querying, exploring and learning from large complex knowledge graphs. We demonstrate our techniques through a case study in the domain of lifelong learning and career guidance
In situ solid-liquid extraction enhances recovery of taxadiene from engineered Saccharomyces cerevisiae cell factories
Microbial cell factories express diverse heterologous pathways for the production of a wide range of valuable natural products. However, the recovery and purification of such compounds is a major bottleneck in commercialization. In this study, a novel in situ solid phase adsorption strategy was investigated for enhanced recovery of taxadiene, a precursor to the blockbuster anticancer drug, paclitaxel, from engineered Saccharomyces cerevisiae. A synthetic adsorbent resin (HP-20) was employed to efficiently sequester taxadiene as it was secreted during growth and a carefully optimized desorption solvent was applied following cultivation to maximize recovery of both secreted and intracellular taxadiene, across a range of scales (2 – 250 mL). Resin concentration was found to have an impact on cellular growth, with the high concentration of 12 % (w/v) resulting in fragmentation of the resin beads, which was detrimental to growth. The optimal resin concentration and desorption solvent combination elucidated at microscale (2 mL) resulted in a two-fold improvement in taxadiene titer to 61 ± 8 mg/L, compared to the traditional liquid-liquid extraction approach (dodecane overlay). Taxadiene was found to be distributed evenly between resin beads and biomass. Performance of the optimal process was subsequently investigated through scale-up using controlled mini-bioreactors (250 mL). Here, a comparable taxadiene titer of 76 ± 19 mg/L was achieved despite a 125-fold scale-up in cultivation volume. This represented a 1.4-fold improvement in taxadiene recovery compared to previous mini-bioreactor scale cultivations using the dodecane overlay extraction approach
Comparison of questionnaire exposure data to land cover map from geographical information system to assess passive exposure to pesticides: a methodological study
Background: Exposure assessment based on questionnaires is frequently implemented in case-control studies, but possible information and recall bias could lead to misclassification of exposure.
Methods: We evaluated passive exposure to pesticides as possible environmental risk factors for amyotrophic lateral scle-rosis (ALS) using a questionnaire mailed to participants in a case-control study in Emilia Romagna and Sicily. Results from questionnaire assessment were com-pared with a remote sensing methodology based on geographical information system, i.e. the land use within a circular 100-meter area around subjects' residence. Since land cover maps were made available only about once every ten years, we used the 2003 and 2009 maps for Emilia-Romagna and Sicily, respectively. Thus, we estimated the percent-age of 'recent' total crop density close to each participant's home, setting positive exposure above 10% of land use. Finally, we calculated the agreement between the two different methodologies using Cohen‟s kappa coefficients for all subjects, cases and controls.
Results and Conclusions: Cohen's kappa was 0.364 (95% CI 0.158-0.569) in total population, 0.378 (0.056-0.700) in cases and 0.354 (0.090-0.618) in controls using the most recent land use map available close to year of case diagnosis. Although a moderate-to-low agreement could be seen between two exposure methods, similar results were found in both cases and controls, suggesting that no recall bias occurred in the most recent period.
In the future, we plan to compare such agreement using historical residence over the 20-30 years prior to diagnosis, in order to validate the long-term exposure to pesticides in subjects
SMaRT lncRNA controls translation of a G-quadruplex-containing mRNA antagonizing the DHX36 helicase
Guanine-quadruplexes (G4) included in RNA molecules exert several functions in controlling gene expression at post-transcriptional level; however, the molecular mechanisms of G4-mediated regulation are still poorly understood. Here, we describe a regulatory circuitry operating in the early phases of murine muscle differentiation in which a long non-coding RNA (SMaRT) base pairs with a G4-containing mRNA (Mlx-γ) and represses its translation by counteracting the activity of the DHX36 RNA helicase. The time-restricted, specific effect of lnc-SMaRT on the translation of Mlx-γ isoform modulates the general subcellular localization of total MLX proteins, impacting on their transcriptional output and promoting proper myogenesis and mature myotube formation. Therefore, the circuitry made of lnc-SMaRT, Mlx-γ, and DHX36 not only plays an important role in the control of myogenesis but also unravels a molecular mechanism where G4 structures and G4 unwinding activities are regulated in living cells
Expanding phenotype of schimke immuno-osseous dysplasia: Congenital anomalies of the kidneys and of the urinary tract and alteration of nk cells
Schimke immuno-osseous dysplasia (SIOD) is a rare multisystemic disorder with a variable clinical expressivity caused by biallelic variants in SMARCAL1. A phenotype\u2013genotype correlation has been attempted and variable expressivity of biallelic SMARCAL1 variants may be associated with environmental and genetic disturbances of gene expression. We describe two siblings born from consanguineous parents with a diagnosis of SIOD revealed by whole exome sequencing (WES). Results: A homozygous missense variant in the SMARCAL1 gene (c.1682G>A; p.Arg561His) was identified in both patients. Despite carrying the same variant, the two patients showed substantial renal and immunological phenotypic differences. We describe features not previously associated with SIOD\u2014both patients had congenital anomalies of the kidneys and of the urinary tract and one of them succumbed to a classical type congenital mesoblastic nephroma. We performed an extensive characterization of the immunophenotype showing combined immunodeficiency characterized by a profound lymphopenia, lack of thymic output, defective IL-7R\u3b1 expression, and disturbed B plasma cells differentiation and immunoglobulin production in addition to an altered NK-cell phenotype and function. Conclusions: Overall, our results contribute to extending the phenotypic spectrum of features associated with SMARCAL1 mutations and to better characterizing the underlying immunologic disorder with critical implications for therapeutic and management strategies
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