152 research outputs found

    The effects of microRNAs on human neural stem cell differentiation in two- and three-dimensional cultures

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    INTRODUCTION: Stem cells have the ability to self-renew or to differentiate into numerous cell types; however, our understanding of how to control and exploit this potential is currently limited. An emerging hypothesis is that microRNAs (miRNAs) play a central role in controlling stem cell-fate determination. Herein, we have characterized the effects of miRNAs in differentiated human neural stem cells (hNSCs) by using a cell line currently being tested in clinical trials for stroke disability (NCT01151124, Clinicaltrials.gov). METHODS: HNSCs were differentiated on 2- (2D) and 3-dimensional (3D) cultures for 1 and 3 weeks. Quantification of hNSC differentiation was measured with real-time PCR and axon outgrowth. The miRNA PCR arrays were implemented to investigate differential expression profiles in differentiated hNSCs. Evaluation of miRNA effects on hNSCs was performed by using transfection of miRNA mimics, real-time PCR, Western blot, and immunocytochemistry. RESULTS: The 3D substrate promoted enhanced hNSC differentiation coupled with a loss of cell proliferation. Differentiated hNSCs exhibited a similar miRNA profiling. However, in 3D samples, the degree and timing of regulation were significantly different in miRNA members of cluster mi-R17 and miR-96-182, and hsa-miR-302a. Overall, hNSC 3D cultures demonstrated differential regulation of miRNAs involved in hNSC stemness, cell proliferation, and differentiation. The miRNA mimic analysis of hsa-miR-146b-5p and hsa-miR-99a confirmed induction of lineage-committed progenitors. Downregulated miRNAs were more abundant; those most significantly downregulated were selected, and their putative target mRNAs analyzed with the aim of unraveling their functionality. In differentiated hNSCs, downregulated hsa-miR-96 correlated with SOX5 upregulation of gene and protein expression; similar results were obtained for hsa-miR-302a, hsa-miR-182, hsa-miR-7, hsa-miR-20a/b, and hsa-miR-17 and their target NR4A3. Moreover, SOX5 was identified as a direct target gene of hsa-miR-96, and NR43A, a direct target of hsa-miR-7 and hsa-mir-17 by luciferase reporter assays. Therefore, the regulatory role of these miRNAs may occur through targeting NR4A3 and SOX5, both reported as modulators of cell-cycle progression and axon length. CONCLUSIONS: The results provide new insight into the identification of specific miRNAs implicated in hNSC differentiation. These strategies may be exploited to optimize in vitro hNSC differentiation potential for use in preclinical studies and future clinical applications

    Economics of Preserving Eucalypt Woodland: Dieback Control, Preservation of Woodland and Choices

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    Grazing properties in southern New England have approximately one third of their land as woodland. Half of this woodland is dying due to the set of diseases and conditions known as eucalypt dieback. There appear to be substantial external costs from the decline and the death of this woodland, and the control of the problem provides many public-good benefits. The attitudes of a relevant segment of the public to eucalypt dieback have been sought, their preferences for different control measures have been elicited and analysed. The choices between alternative woodland types, and preservation benefits were also studied and analysed in the process. The results in this study have been obtained by regression analyses of cross-sectional survey data. Relatively straightforward regression analyses helped determine the magnitudes of recreation, existence, and option values. To estimate the demand for alternative dieback control measures, a system of demand equations was estimated jointly by Zellner's method of seemingly unrelated regressions. A single equation estimated by ordinary least squares was used to choose between alternative types of eucalypt woodland to preserve. The recreation, existence, and option values were estimated by the direct question method approved by the U.S. Water Resources Council in 1979. Respondents' willingness-to-pay determined these preservation values. The preferences for alternative control measures, and choice between alternative types of eucalypt woodland to preserve were determined through a budget-allocation game following Hardie and Strand (1978). This game appears to overcome the free-rider difficulty inherent in the demand for public goods. This study indicates that the individuals who respond are very concerned to improve the health of the surrounding woodland. They would appear to be willing to help fund research into the dieback problem, and would benefit from the knowledge that dieback would be reduced. The demand for dieback control indicates preferences for eucalypt alternatives like preserving mature trees, and fencing-out-stock from young eucalypt regeneration, rather than other plausible control measures. Apparently members of the sample had no consistent rational preferences for introduced tree species. Between the biological characteristics for choices between woodland types, they picked healthiness as the most important attribute of woodland

    An Evaluation of the Gerangamete Catchment Management Plan Using the Safe Minimum Standard

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    In this study an evaluation of the catchment management plan for the Gerangamete catchment is undertaken. This catchment suffers from dryland salinity which is a result of current landuse practices, and can only be solved by changing those practices. Current methods of land use evaluation have been criticised for their inflexibility and lack of attention to costs (both private and social) associated with particular land use activities. These deficiencies can limit the usefulness of land evaluation procedures for defining land capability and suitability for farm and regional land use planning for salinity control. In this study a method is outlined, which is based on incorporating deterministic spreadsheet modelling and risk analysis using simulation modelling which overcomes some of these deficiencies. The technique integrates biophysical and economic data in a measure which can be readily computed, updated and communicated to land managers

    Evaluation of the Private and Social Costs of an On-Farm Biodiversity Conservation Program in Western New South Wales

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    Native vegetation, and its associated biodiversity, are becoming scarce in Australia and therefore valued resources to society. A significant quantity of native vegetation exists on privately managed farmlands, and so these landholders can play an important role in management and conservation. They do not, however, always conserve biodiversity at a level society desires because they do not receive the appropriate market signals. Consequently, regulations and other policy measures to protect native vegetation on farms have been introduced in all jurisdictions of Australia. But these regulatory policies can impose substantial costs to landholders, and may be ineffective in the provision of biodiversity and environmental outcomes, so they need to be continually reviewed. Recently the use of Market Based Instruments (MBI's) has received considerable attention. These instruments are based on the premise that the socially optimal level of biodiversity is not being conserved due to market failures. They are used to create a market that provides both incentives and signals to farmers to produce improved levels of environmental goods and services. The Western Division of New South Wales has primarily been used for grazing sheep on native pasture, and is characterised by large properties and marginal climatic conditions. Environmental issues in the region include soil erosion, encroachment of woody weeds and the decline of the pasture and groundcover conditions. Currently less than eight per cent of the Western Division is formally managed with conservation objectives, however the Western Catchment Management Authority hopes to raise this to 25 per cent conservation by 2035. This, amongst other factors has led to an interest in MBI's as a method of increasing conservation outcomes in this region

    Aluminum Direct Chill Casting Mold Metal Shutoff Methods

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    The systems and methods described herein may prevent mold damage, which would otherwise result in significant down time and costly repairs or replacement

    Economic analysis of crop-livestock integration: The case of the Ethiopian highlands

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    This study is concerned with the impact of crop-livestock integration on food production and farm incomes in highland farming systems in Ethiopia. Structural food deficits and rural poverty are important household and economy-wide problems. The study uses empirical data that were obtained from 900 rural households in 23 villages in the low potential cereal livestock agro-ecological zone of the Ethiopian highlands. Using stratified random sampling, data were collected through direct measurements, structured formal questionnaires, field observations, group interviews and from secondary sources. Statistical techniques (e.g., principal components) and whole-farm linear programming have been applied to complete the analysis
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