204 research outputs found

    Regulation of Emx2 expression by antisense transcripts in murine cortico-cerebral precursors

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    Background: Emx2 encodes for a transcription factor expressed in the embryonic intermediate mesoderm and central nervous system (CNS). It is implicated in several aspects of cerebral cortex development, including morphogenetic field specification, arealization, precursor proliferation and lamination. Four Emx2-associated antisense transcripts have been found in the urogenital system; one of them, Emx2OS, has been also detected in the adult brain. Until now, however, nothing is known about expression and function of Emx2OS in the developing CNS. Methodology/Principal Findings: By quantitative RT-PCR and in situ hybridization, we reconstructed the Emx2OS expression profile in the embryonic CNS, paying special attention to the developing cerebral cortex. Emx2OS was observed in a number of CNS structures expressing also Emx2. Within the cortex, Emx2OS was detectable in periventricular precursors, expressing the sense transcript, and peaked in newly born post-mitotic neurons not expressing such transcript. By integrating lentiviral gene delivery, RNAi, TetON technology, morpholino-mediated gene knock-down, drug-induced perturbation of gene expression, and quantitative RT-PCR, we addressed possible roles of Ex2 antisense RNA in Emx2 regulation, in primary CNS precursor cultures. We found that, in both cortical precursors and their neuronal progenies, Emx2 antisense RNA contributes to post-transcriptional down-regulation of its sense partner, possibly by a Dicer-promoted mechanism. The same RNA, when delivered to rhombo-spinal precursors, stimulates ectopic expression of Emx2, whereas Emx2 knock-out dramatically impairs Emx2OS transcription. This suggests that, within the developing CNS, a reciprocal Emx2/Emx2OS regulatory loop may normally sustain transcription at the Emx2 locus. Conclusions/Significance: This study shows that antisense transcripts may contribute to developmental regulation of a key transcription factor gene implicated in CNS patterning, possibly by complex and multilevel mechanisms. The activation of Emx2 by a short antisense transcript may be a prototype of a method for overexpressing single specific genes, without introducing additional copies of them into the genome

    Intervention Strategies against and Effects of Female Sexual Harassment in Workplaces of Cote d\u27Ivoire

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    Workplace sexual harassment in Cote d\u27Ivoire has been documented as extensive and commonplace, yet in West African nations, sexual harassment is not well studied or understood. Specifically, little is known about whether intervention programs instituted by the Ivorian law under Act No.98-756 forbid sexual harassment are viewed by female workers as effective. Using Hendricks and Valasek\u27s theory on gender mainstreaming as the foundation, the purpose of this study was to evaluate the perceptions of female workers in Cote d\u27Ivoire related the effectiveness of sexual harassment training programs. Data for this study were collected from 15 women who worked in public or nonprofit organizations in Cote d\u27Ivoire. Data were inductively coded and then subjected to a thematic analysis procedure. Key findings indicated that interviewees believed that exposure to sexual harassment in the workplace results in a loss of trust in the work environment and reductions in work productivity. Further, participants generally agreed that intervention programs are promising in terms of ameliorating the effects of sexual harassment and gender discrimination in the workplace. The positive social change implications stemming from this study include recommendations to local governments in Cote d\u27Ivoire to develop municipal ordinances that support the investigation and prosecution of workplace sexual harassment and individual organizations should design workplace policies to efficiently and effectively handle complaints of sexual harassment

    Innovative design and multi-objective optimization of hybrid reverse osmosis and multi-stage flash desalination plants

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    The purpose of this work is to develop a decision support tool, which will systemically assess the advantages of hybrid desalination configurations (integration between thermal and membrane technologies) by investigating and optimizing these configurations as a function of project requirements and local conditions

    Multi-objective optimization of RO desalination plants

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    A process optimization method has been developed for the design of reverse osmosis (RO) processes. RO process configurations are systematically generated using a flexible superstructure and evaluated by economical (investment and operating costs), technical (energy requirement, water recovery rate) and environmental performance indicators (Life Cycle Assessment). The simultaneous optimization of the RO process layout and operating conditions constitutes a mixed-integer nonlinear programming (MINLP) problem, which is solved using a multi-objective optimization (MOO) approach. The MOO identifies the best technological alternatives for the set of selected objectives. In a given context, it allows to define a set of optimal solutions representing the trade-off between conflicting objectives such as economical costs and environmental impacts. As a case study, the methodology is applied on a brackish water reverse osmosis (BWRO) desalination project, for which the optimal design is characterized depending on the economical conditions

    Developmental expression of Pim kinases suggests functions also outside of the hematopoietic system

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    We have cloned a novel quail cDNA with strong homology to the pint family of proto-oncogenes. The deduced amino acid (aa) sequence of the cDNA, named qpim, is more closely related to Xenopus Pim and to the recently identified rat Pim-3 than to human or rodent Pim-1 or Pim-2. The protein encoded by the qpim cDNA can autophosphorylate itself and share substrates with murine Pim-l, suggesting functional redundancy to other Pim family serine/threonine kinases. We have compared the expression of qpim in avian embryos to mouse pim-1, -2 and -3 by in situ hybridization. qpim shows a highly dynamic expression pattern, particularly at early developmental stages. Surprisingly, its expression pattern is not identical to any of the murine pint genes, which show complementary and/or partially overlapping expression sites both in- and outside of the hematopoietic system. Altogether, our results suggest novel functions for Pim family kinases during embryonic development, in particular in epithelia and in the central nervous system

    Single stage electrochemical exfoliation method for the production of few-layer graphene via intercalation of tetraalkylammonium cations

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    We present a non-oxidative production route to few layer graphene via the electrochemical intercalation of tetraalkylammonium cations into pristine graphite. Two forms of graphite have been studied as the source material with each yielding a slightly different result. Highly orientated pyrolytic graphite (HOPG) offers greater advantages in terms of the exfoliate size but the source electrode set up introduces difficulties to the procedure and requires the use of sonication. Using a graphite rod electrode, few layer graphene flakes (2 nm thickness) are formed directly although the flake diameters from this source are typically small (ca. 100–200 nm). Significantly, for a solvent based route, the graphite rod does not require ultrasonication or any secondary physical processing of the resulting dispersion. Flakes have been characterized using Raman spectroscopy, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS)

    Petit guide pratique pour la gestion des projets d'assainissement : fascicule 1 : les réseaux

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    L'étude et la mise en œuvre de canalisations d'assainissement doivent répondre à un nombre croissant d'exigences techniques, économiques et environnementales . Le guide apporte des recommandations essentielles pour une gestion rigoureuse des projets à même de répondre à de telles exigences. Il aborde successivement les points suivants : la prise de commande, les différentes contraintes (la loi sur l'eau, les aides au financement, les contraintes d'urbanisme, la coordination générale des réseaux, les études techniques préalables, l'hygiène et la sécurité de chantier, l'exploitation future du réseau), l'ordonnancement du projet, les dossiers techniques, la dévolution des travaux, la préparation de chantier, la qualité de mise en œuvre des remblais, la réception des travaux

    Species-specific differences in the expression of the HNF1A, HNF1B and HNF4A genes

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    Background: The HNF1A, HNF1B and HNF4A genes are part of an autoregulatory network in mammalian pancreas, liver, kidney and gut. The layout of this network appears to be similar in rodents and humans, but inactivation of HNF1A, HNF1B or HNF4A genes in animal models cause divergent phenotypes to those seen in man. We hypothesised that some differences may arise from variation in the expression profile of alternatively processed isoforms between species. Methodology/Principal Findings: We measured the expression of the major isoforms of the HNF1A, HNF1B and HNF4A genes in human and rodent pancreas, islet, liver and kidney by isoform-specific quantitative real-time PCR and compared their expression by the comparative Ct (??Ct) method. We found major changes in the expression profiles of the HNF genes between humans and rodents. The principal difference lies in the expression of the HNF1A gene, which exists as three isoforms in man, but as a single isoform only in rodents. More subtle changes were to the balance of HNF1B and HNF4A isoforms between species; the repressor isoform HNF1B(C) comprised only 6% in human islets compared with 24–26% in rodents (p = 0.006) whereas HNF4A9 comprised 22% of HNF4A expression in human pancreas but only 11% in rodents (p = 0.001). Conclusions/Significance: The differences we note in the isoform-specific expression of the human and rodent HNF1A, HNF1B and HNF4A genes may impact on the absolute activity of these genes, and therefore on the activity of the pancreatic transcription factor network as a whole. We conclude that alterations to expression of HNF isoforms may underlie some of the phenotypic variation caused by mutations in these genes

    Pericyte Seeded Dual Peptide Scaffold with Improved Endothelialization for Vascular Graft Tissue Engineering

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    At times when rhinoceros are fiercely poached, when some rhinoceros species are closer than ever to extinction, and when the scientific community is in debate over the use of advanced cell technologies as a remaining resort it is time to simplify and improve existing assisted reproduction techniques to enhance breeding and genetic diversity in the living populations under our care. Semen cryopreservation has been performed in all captive rhinoceros species with limited degree of success. Here we tested three freezing extenders, containing different cryoprotectants and various freezing rates for the cryopreservation of rhinoceros sperm from 14 bulls. In experiment I, semen from 9 bulls was used to determine the most suitable diluent, cryoprotectant and freezing rate for the successful cryopreservation of rhinoceros sperm. In experiment II, semen from 5 bulls was used to assess whether the removal of seminal plasma could further improve post thaw sperm quality following cryopreservation with conditions identified in Experiment I. Semen was diluted with Berliner Cryomedia, ButoCrio® or INRA Freeze®, packaged in 0.5 mL straws and frozen 3, 4, and 5 cm over liquid nitrogen (LN) vapour or directly in a dryshipper. It was found that semen extended with ButoCrio® (containing glycerol and methylformamide) and frozen 3cm over LN vapour provided the best protection to rhinoceros spermatozoa during cryopreservation. When pooled over treatments, total and progressive post thaw motility was 75.3 ± 4.2% and 68.5 ± 5.7%, respectively marking a new benchmark for the cryopreservation of rhinoceros sperm. Post thaw total and progressive motility, viability and acrosome integrity of semen diluted in ButoCrio® was significantly higher than semen extended in Berliner Cryomedia or INRA Freeze®. The removal of seminal plasma did not improve post thaw sperm survival (p > 0.05). In conclusion, the cryosurvival of rhinoceros spermatozoa was significantly improved when using a mixture of glycerol and methylformamide in combination with a fast freezing rate at 3 cm. These results describe a new protocol for the improved cryosurvival of rhinoceros spermatozoa and will enable a more successful preservation of genetic diversity between males, especially in donors whose spermatozoa may already be compromised prior to or during collection. The successful reduction of glycerol concentration in favour of methylformamide as a cryoprotectant could be a novel suggestion for the improvement of cryopreservation techniques in other wildlife species
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