1,798 research outputs found

    The cyclin-dependent kinase inhibitor Orysa;KRP1 plays an important role in seed development of rice

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    Kip-related proteins (KRPs) play a major role in the regulation of the plant cell cycle. We report the identification of five putative rice (Oryza sativa) proteins that share characteristic motifs with previously described plant KRPs. To investigate the function of KRPs in rice development, we generated transgenic plants overexpressing the Orysa; KRP1 gene. Phenotypic analysis revealed that overexpressed KRP1 reduced cell production during leaf development. The reduced cell production in the leaf meristem was partly compensated by an increased cell size, demonstrating the existence of a compensatory mechanism in monocot species by which growth rate is less reduced than cell production, through cell expansion. Furthermore, Orysa; KRP1 overexpression dramatically reduced seed filling. Sectioning through the overexpressed KRP1 seeds showed that KRP overproduction disturbed the production of endosperm cells. The decrease in the number of fully formed seeds was accompanied by a drop in the endoreduplication of endosperm cells, pointing toward a role of KRP1 in connecting endocycle with endosperm development. Also, spatial and temporal transcript detection in developing seeds suggests that Orysa; KRP1 plays an important role in the exit from the mitotic cell cycle during rice grain formation

    Tensiometric estimation of material properties of tissue spheroids

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    Tissue spheroids have been proposed to use as building blocks in biofabrication and as bioinks in 3D bioprinting technologies. Tissue fusion is an ubiqious phenomenon during embryonic development. Biomimetic tissue spheroid fusion is a fundamental constructional principle of emerging organ printing technology because closely placed tissue spheroids could fuse into tissue and organ-like constructs in fusion permissive bioprintable hydrogel. From physical point of view tissue spheroids could be considered as a visco-elastic-plastic soft matter or complex fluid. We hypothesize that quantitative estimation of material properties of tissue spheroids using tensiometry could predict their tissue spreading and tissue fusion behavior as well as provide a powerful insight about possible speed of post-printed tissue and organ-like constructs compaction and maturation. Tissue spheroids from human fibroblasts, ovine and human chondrocytes and immortalised human keratinocytes have been biofabricated using non-adhesive cell culture plates (Corning, USA). For estimation of material properties of tissue spheroids commercial tensiometer Microsquisher have been emploied (CellScale, Toronto, Canada). Modulus of elasticity of tissue spheroids have been calculated based on peformed tissue compression tests. In order to identify structural determinants of material properties of tissue spheroids standard perturbants of cytoskeleton such as Cytochalasin D (Sigma, USA) for disruption of microfilaments and Nocodazole (Sigma, USA) for disruption of microtubules have been used. Viability of tissue spheroids have been also estimated and their morphology have been analysed using light microscopy, histochemistry, immunohistochemistry, semithin sections stained wih toluidine blue and transmission and scanning electron microscopy. Kinetics of tissue spheroids spreading on electrospun polyurethane matrices have been analysed. Kinetics of two closely placed tissue spheroids fusion have been analysed in hanging drop. Additionally toxic effect of water solution of paramagnetic gadolinium salt (OmniscanĀ®, GE Health Care, USA) on material properties of tissue spheroids have been investigated. It have been demonstrated that material properties of tissue spheroids biofabricated from different cell types have different modulus of elasticity. Even tissue spheroids biofabricated the same cell types but from different species have different material properties. Incubation with Cytochlasin D dramatically reduces estimated material properties of tissue spheroids. Incubation with Nocodazole does not significantly change material properties of tissue spheroids. Material properties of tissue spheroids from chondrocytes (chondrospheres) correlates very well with increasing deposition and accumulation of extracellular matrix (confirmed by expression of collagen type II and glycosoaminoglycans). The incubation with toxic concentration of gadolinium solution dramatically reduces material properties of chondrospheres. There is no any significant correlation between material properties of tissue spheriods and their spreading kinetics. However, there is a certain correction between material properties of tissue spheroids and their tissue fusion kinetics. Our data demonstrate that beside already well established role of cell adhesion receptors such as cadherin and integrins in the realisation of cell cohesion inside tissue spheroids the structural determinants of material properties of tissue spheroids also include components of cytoskeleton such as actin micofilaments and accumulated extracellular matrix. It is possible to predict post-printing tissue fusion behaviour of tissue spheroids based on preliminary estimation of their material properties. Finally, it have been also shown that material properties of tissue spheroids correlate with their viability. Thus, tensiometry is a valuable method for systematic characterization of material properties of tissue spheroids and for prediction of tissue spheroids post-printed tissue fusion behaviour

    Development of methods of phosphorylation of citral by medial and acidic phosphites

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    The reactions of trimethyl phosphite with citral in the presence of acetic acid, triphenyl phosphite with citral in the presence of water and trimethyl phosphite with citral in the presence of water and triethylamine in the methanol solution were studied. On the basis of these studies, dienyl 1-hydroxyphosphonates were obtained. A convenient method of synthesizing unsaturated 1-hydroxyphosphonates was developed on the basis of reaction of dialkyl phosphites with citral in the presence of triethylamine in molar ratio 4:2:8 in alcohol solutions

    Phosphineoxide-Chelated Europium(III) Nanoparticles for Ceftriaxone Detection

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    The present work demonstrates the optimization of the ligand structure in the series of bis(phosphine oxide) and Ī²-ketophosphine oxide representatives for efficient coordination of Tb3+ and Eu3+ ions with the formation of the complexes exhibiting high Tb3+- and Eu3+-centered luminescence. The analysis of the stoichiometry and structure of the lanthanide complexes obtained using the XRD method reveals the great impact of the bridging group nature between two phosphine oxide moieties on the coordination mode of the ligands with Tb3+ and Eu3+ ions. The bridging imido-group facilitates the deprotonation of the imido- bis(phosphine oxide) ligand followed by the formation of tris-complexes. The spectral and PXRD analysis of the separated colloids indicates that the high stability of the tris-complexes provides their safe conversion into polystyrenesulfonate-stabilized colloids using the solvent exchange method. The red Eu3+-centered luminescence of the tris-complex exhibits the same specificity in the solutions and the colloids. The pronounced luminescent response on the antibiotic ceftriaxone allows for sensing the latter in aqueous solutions with an LOD value equal to 0.974 Ī¼M

    Biofabrication : reappraising the definition of an evolving field

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    Biofabrication is an evolving research field that has recently received significant attention. In particular, the adoption of Biofabrication concepts within the field of Tissue Engineering and Regenerative Medicine has grown tremendously, and has been accompanied by a growing inconsistency in terminology. This article aims at clarifying the position of Biofabrication as a research field with a special focus on its relation to and application for Tissue Engineering and Regenerative Medicine. Within this context, we propose a refined working definition of Biofabrication, including Bioprinting and Bioassembly as complementary strategies within Biofabrication

    Alignment of the CMS tracker with LHC and cosmic ray data

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    Ā© CERN 2014 for the benefit of the CMS collaboration, published under the terms of the Creative Commons Attribution 3.0 License by IOP Publishing Ltd and Sissa Medialab srl. Any further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation and DOI.The central component of the CMS detector is the largest silicon tracker ever built. The precise alignment of this complex device is a formidable challenge, and only achievable with a significant extension of the technologies routinely used for tracking detectors in the past. This article describes the full-scale alignment procedure as it is used during LHC operations. Among the specific features of the method are the simultaneous determination of up to 200 000 alignment parameters with tracks, the measurement of individual sensor curvature parameters, the control of systematic misalignment effects, and the implementation of the whole procedure in a multi-processor environment for high execution speed. Overall, the achieved statistical accuracy on the module alignment is found to be significantly better than 10Ī¼m
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