309 research outputs found

    Shape-Selective Supramolecular Capsules for Actinide Precipitation and Separation

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    Improving actinide separations is key to reducing barriers to medical and industrial actinide isotope production and to addressing the challenges associated with the reprocessing of spent nuclear fuel. Here, we report the first example of a supramolecular anion recognition process that can achieve this goal. We have designed a preorganized triamidoarene receptor that induces quantitative precipitation of the early actinides Th(IV), Np(IV), and Pu(IV) from industrially relevant conditions through the formation of self-assembled hydrogen-bonded capsules. Selectivity over the later An(III) elements is shown through modulation of the nitric acid concentration, and no precipitation of actinyl or transition-metal ions occurs. The Np, Pu, and Am precipitates were characterized structurally by single-crystal X-ray diffraction and reveal shape specificity of the internal hydrogen-bonding array for the encapsulated hexanitratometalates. This work complements ion-exchange resins for 5f-element separations and illustrates the significant potential of supramolecular separation methods that target anionic actinide species

    Viral Transfer and Inactivation through Zooplankton Trophic Interactions

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    Waterborne viruses are responsible for numerous diseases and are abundant in aquatic systems. Understanding the fate of viruses in natural systems has important implications for human health. This research quantifies the uptake of the bacteriophage T4 and the enteric virus echovirus 11 when exposed to the filter feeders Tetrahymena pyriformis and Daphnia magna, and also examines the potential of viral transfer due to trophic interactions. Experiments co-incubating each species with the viruses over 72-96 h showed up to a 4 log virus removal for T. pyriformis, while direct viral uptake by D. magna was not observed. However, viral uptake by D. magna occurred indirectly by viral transfer from prey to predator, through D. magna feeding on virus-loaded T. pyriformis. This prey-predator interaction resulted in a 1 log additional virus removal compared to removal by T. pyriformis alone. Incomplete viral inactivation by D. magna was observed through recovery of infective viruses from the daphnid tissue. This research furthers our understanding of the impacts of zooplankton filter feeding on viral inactivation and shows the potential for viral transfer through the food chain. The viral-zooplankton interactions observed in these studies indicate that zooplankton may improve water quality through viral uptake or may serve as vectors for infection by accumulating viruses

    All grown up? The fate after 15 years of a quarter of a million UK firms born in 1998

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    The theory of firm growth is in a rather unsatisfactory state. However, the analysis of large firm-level datasets which have become available in recent years allows us to begin building an evidence base which can, in turn, be used to underpin the development of more satisfactory theory. Here we study the 239 thousand UK private sector firms born in 1998 over their first 15 years of life. A first, and quite striking, finding is the extraordinary force of mortality. By age 15, 90% of the UK firms born in 1998 are dead, and, for those surviving to age 15, the hazard of death is still about 10% a year. The chance of death is related to the size and growth of firms in an interesting way. Whilst the hazard rate after 15 years is largely independent of size at birth, it is strongly affected by the current (age 14) size. In particular, firms with more than five employees are half as likely to die in the next year as firms with less than five employees. A second important finding is that most firms, even those which survive to age 15, do not grow very much. By age 15 more than half the 26,000 survivors still have less than five jobs. In other words, the growth paths – what we call the ‘growth trajectories’ – of most of the 26,000 survivors are pretty flat. However, of the firms that do grow, firms born smaller grow faster than those born larger. Another striking finding is that growth is heavily concentrated in the first five years. Whilst growth does continue, even up to age 15, each year after age five it involves only a relatively small proportion of firms. Finally, there are two groups of survivors which contribute importantly to job creation. Some are those born relatively large (with more than 20 jobs) although their growth rate is quite modest. More striking though, is a very small group of firms born very small with less than five jobs (about 5% of all survivors) which contribute a substantial proportion (more than one third) of the jobs added to the cohort total by age 15

    A study of patent thickets

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    Report analysing whether entry of UK enterprises into patenting in a technology area is affected by patent thickets in the technology area

    Therapeutic Targeting of ATP7B in Ovarian Carcinoma.

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    PURPOSE: Resistance to platinum chemotherapy remains a significant problem in ovarian carcinoma. Here, we examined the biological mechanisms and therapeutic potential of targeting a critical platinum resistance gene, ATP7B, using both in vitro and in vivo models. EXPERIMENTAL DESIGN: Expression of ATP7A and ATP7B was examined in ovarian cancer cell lines by real-time reverse transcription-PCR and Western blot analysis. ATP7A and ATP7B gene silencing was achieved with targeted small interfering RNA (siRNA) and its effects on cell viability and DNA adduct formation were examined. For in vivo therapy experiments, siRNA was incorporated into the neutral nanoliposome 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC). RESULTS: ATP7A and ATP7B genes were expressed at higher levels in platinum-resistant cells compared with sensitive cells; however, only differences in ATP7B reached statistical significance. ATP7A gene silencing had no significant effect on the sensitivity of resistant cells to cisplatin, but ATP7B silencing resulted in 2.5-fold reduction of cisplatin IC(50) levels and increased DNA adduct formation in cisplatin-resistant cells (A2780-CP20 and RMG2). Cisplatin was found to bind to the NH(2)-terminal copper-binding domain of ATP7B, which might be a contributing factor to cisplatin resistance. For in vivo therapy experiments, ATP7B siRNA was incorporated into DOPC and was highly effective in reducing tumor growth in combination with cisplatin (70-88% reduction in both models compared with controls). This reduction in tumor growth was accompanied by reduced proliferation, increased tumor cell apoptosis, and reduced angiogenesis. CONCLUSION: These data provide a new understanding of cisplatin resistance in cancer cells and may have implications for therapeutic reversal of drug resistance

    Understanding how immigrant entrepreneurs view business opportunity formation through ethnicity

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    Given that international research is now consistently showing higher rates of entrepreneurial activity from immigrants above native people, research regarding our understanding of how immigrant entrepreneurs view business opportunity formation remains underdeveloped. Based upon a review of the literature, this chapter examines how ethnicity relates to business opportunity formation through constant interactions. It also introduces the Visual Mixed Embeddedness Framework as an empirical lens for understanding the differences in the business opportunity formation process models between immigrant and native entrepreneurs. By explaining how factors and traits from both home and host countries impact upon the immigrant entrepreneurial business activity process, the framework clearly identifies how the concept of ethnicity influences immigrant entrepreneurial opportunity formation activities in different ways. The framework contributes to existing knowledge by offering a novel method for examining the influence on business opportunity formation of ethnicity, the role of home and host countries and variations between immigrant and native entrepreneurs

    High-growth firms and productivity:evidence from the United Kingdom

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    Abstract There is considerable evidence that high-growth firms (HGFs) contribute significantly to employment and economic growth. However, the literature so far does not adequately explore the link between HGFs and productivity. This paper investigates the empirical link between total factor productivity (TFP) growth and HGFs, defined in terms of sales growth, in the United Kingdom over the period 2001-2010, by examining two related research questions. Firstly, does higher TFP growth lead to HGF status and secondly, does HGF experience help firms achieve faster TFP growth? Our findings reveal that firms in both the manufacturing and services sectors are more likely to become HGFs when they exhibit higher TFP growth. In addition, firms that have had HGF experience tend to enjoy faster TFP growth following the high-growth episodes. Policy implications are drawn based on the self-reinforcing process of the high-growth phenomenon that is revealed by our results

    What is the value of entrepreneurship?: a review of recent research

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    This paper examines to what extent recent empirical evidence can collectively and systematically substantiate the claim that entrepreneurship has important economic value. Hence, a systematic review is provided that answers the question: What is the contribution of entrepreneurs to the economy in comparison to non-entrepreneurs? We study the relative contribution of entrepreneurs to the economy based on four measures that have most widely been studied empirically. Hence, we answer the question: What is the contribution of entrepreneurs to (i) employment generation and dynamics, (ii) innovation, and (iii) productivity and growth, relative to the contributions of the entrepreneurs counterparts, i.e. the control group? A fourth type of contribution studied is the role of entrepreneurship in increasing individuals utility levels. Based on 57 recent studies of high quality that contain 87 relevant separate analyses, we conclude that entrepreneurs have a very important but specific function in the economy. They engender relatively much employment creation, productivity growth and produce and commercialize high quality innovations. They are more satisfied than employees. More importantly, recent studies show that entrepreneurial firms produce important spillovers that affect regional employment growth rates of all companies in the region in the long run. However, the counterparts cannot be missed either as they account for a relatively high value of GDP, a less volatile and more secure labor market, higher paid jobs and a greater number of innovations and they have a more active role in the adoption of innovations

    Improving financial capability: the mediating role of financial behaviour

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    This paper investigates the collective impact of financial literacy and inclusion on individuals’ financial capability focusing on the mediating role of financial behaviour. The research is conducted on an individual-level survey. The relationships were examined by using PLS-SEM. Financial capability can be improved by increasing individuals’ financial knowledge, financial behaviour and promoting their inclusion in financial services. Furthermore, the indirect effect of financial knowledge and attitude on financial capability is found to be significant, highlighting the importance of financial behaviour. The results assist policymakers and industry leaders in understanding the most influential factors on financial capability in the context of a post-communist transition country. This enables them to design policies and services aimed at equipping citizens with knowledge and skills to make best use of their financial resources. © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.Internal Grant Agency of FaME TBU [IGA/FaME/2019/002
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