472 research outputs found

    Calcium-phosphate derived from mineralized algae for bone tissue engineering applications

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    In this work, several routes are described towards obtaining pure inorganic phases derived from Coralline officinallis red algae. The scanning electron microscopy studies have shown that it becomes possible not only to eliminate the undesired organic phase, but also to preserve or tailor the red algae typical microporosity. X-ray diffraction analysis was used to investigate the phase content of the red algae before and after performing the different treatment routes. Hydroxyapatite nanocrystallites were obtained after converting the coralline calcium carbonate skeleton by means of combining thermal and chemical routes. These results were confirmed by Fourier transform infra-red spectroscopic analysis. The processing routes herein described are very promising in order to design bioceramics of algae origin that might find useful applications as bone fillers and tissue engineering scaffolds

    Параметрична логістична модель планування роботи різних видів транспорту

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    Запропонована логістична модель планування роботи різних видів транспорту вантажної станції за умов ефективного використання вантажно-розвантажувальних механізмів, вантажних фронтів та складської обробки вантажів.Предложенная логистическая модель планирования работы различных видов транспорта грузовой станции в условиях эффективного использования погрузочно-разгрузочных механизмов, грузовых фронтов и складской обработки грузов.The proposed model of logistic planning of transport modes cargo station for the effective use of material handling equipment, commercial fronts and warehouse handling

    Strong inapproximability of the shortest reset word

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    The \v{C}ern\'y conjecture states that every nn-state synchronizing automaton has a reset word of length at most (n1)2(n-1)^2. We study the hardness of finding short reset words. It is known that the exact version of the problem, i.e., finding the shortest reset word, is NP-hard and coNP-hard, and complete for the DP class, and that approximating the length of the shortest reset word within a factor of O(logn)O(\log n) is NP-hard [Gerbush and Heeringa, CIAA'10], even for the binary alphabet [Berlinkov, DLT'13]. We significantly improve on these results by showing that, for every ϵ>0\epsilon>0, it is NP-hard to approximate the length of the shortest reset word within a factor of n1ϵn^{1-\epsilon}. This is essentially tight since a simple O(n)O(n)-approximation algorithm exists.Comment: extended abstract to appear in MFCS 201

    The excitation spectrum for weakly interacting bosons in a trap

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    We investigate the low-energy excitation spectrum of a Bose gas confined in a trap, with weak long-range repulsive interactions. In particular, we prove that the spectrum can be described in terms of the eigenvalues of an effective one-particle operator, as predicted by the Bogoliubov approximation.Comment: LaTeX, 32 page

    Extreme resistance to Potato virus Y in potato carrying the Rysto gene is mediated by a TIR-NLR immune receptor

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    Potato virus Y (PVY) is a major potato (Solanum tuberosum L.) pathogen that causes severe annual crop losses worth billions of dollars worldwide. PVY is transmitted by aphids, and successful control of virus transmission requires the extensive use of environmentally damaging insecticides to reduce vector populations. Rysto , from the wild relative S. stoloniferum, confers extreme resistance (ER) to PVY and related viruses and is a valuable trait that is widely employed in potato resistance breeding programmes. Rysto was previously mapped to a region of potato chromosome XII, but the specific gene has not been identified to date. In this study, we isolated Rysto using resistance gene enrichment sequencing (RenSeq) and PacBio SMRT (Pacific Biosciences single-molecule real-time sequencing). Rysto was found to encode a nucleotide-binding leucine-rich repeat (NLR) protein with an N-terminal TIR domain and was sufficient for PVY perception and ER in transgenic potato plants. Rysto -dependent extreme resistance was temperature-independent and requires EDS1 and NRG1 proteins. Rysto may prove valuable for creating PVY-resistant cultivars of potato and other Solanaceae crops

    Modelling adult Aedes aegypti and Aedes albopictus survival at different temperatures in laboratory and field settings.

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    BACKGROUND: The survival of adult female Aedes mosquitoes is a critical component of their ability to transmit pathogens such as dengue viruses. One of the principal determinants of Aedes survival is temperature, which has been associated with seasonal changes in Aedes populations and limits their geographical distribution. The effects of temperature and other sources of mortality have been studied in the field, often via mark-release-recapture experiments, and under controlled conditions in the laboratory. Survival results differ and reconciling predictions between the two settings has been hindered by variable measurements from different experimental protocols, lack of precision in measuring survival of free-ranging mosquitoes, and uncertainty about the role of age-dependent mortality in the field. METHODS: Here we apply generalised additive models to data from 351 published adult Ae. aegypti and Ae. albopictus survival experiments in the laboratory to create survival models for each species across their range of viable temperatures. These models are then adjusted to estimate survival at different temperatures in the field using data from 59 Ae. aegypti and Ae. albopictus field survivorship experiments. The uncertainty at each stage of the modelling process is propagated through to provide confidence intervals around our predictions. RESULTS: Our results indicate that adult Ae. albopictus has higher survival than Ae. aegypti in the laboratory and field, however, Ae. aegypti can tolerate a wider range of temperatures. A full breakdown of survival by age and temperature is given for both species. The differences between laboratory and field models also give insight into the relative contributions to mortality from temperature, other environmental factors, and senescence and over what ranges these factors can be important. CONCLUSIONS: Our results support the importance of producing site-specific mosquito survival estimates. By including fluctuating temperature regimes, our models provide insight into seasonal patterns of Ae. aegypti and Ae. albopictus population dynamics that may be relevant to seasonal changes in dengue virus transmission. Our models can be integrated with Aedes and dengue modelling efforts to guide and evaluate vector control, better map the distribution of disease and produce early warning systems for dengue epidemics

    Exploring the Origin of Sentencing Disparities in the Crown Court: Using Text Mining Techniques to Differentiate between Court and Judge Disparities

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    Research on sentence consistency in England and Wales has focused on disparities between courts, with differences between judges generally ignored. This is largely due to the limitations in official data. Using text mining techniques from Crown Court sentence records available online we generate a sample of 7,212 violent and sexual offences where both court and judge are captured. Multilevel time-to-event analyses of sentence length demonstrate that most disparities originate at the judge, not the court-level. Two important implications follow: i) the extent of sentencing consistency in England and Wales has been underestimated; and ii) the importance attributed to the location in which sentences are passed – in England and Wales and elsewhere - needs to be revisited. Further analysis of the judge level disparities identifies judicial rotation across courts as a practice conducive of sentence consistency, which suggests that sentencing guidelines could be complemented with other, less intrusive, changes in judicial practice to promote consistency

    Rhodiola rosea L.:from golden root to green cell factories

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    Rhodiola rosea L. is a worldwide popular plant with adaptogenic activities that have been and currently are exploited in the traditional medicine of many countries, as well as, examined in a number of clinical trials. More than 140 chemical structures have been identified which belong to several natural product classes, including phenylpropanoid glycosides, phenylethanoids, flavonoids and essential oils, and are mainly stored in the rhizomes and the roots of the plant. A number of mechanisms contribute to the adaptogenic activities of R. rosea preparations and its phytochemical constituents. Among them, the intrinsic inducible mammalian stress responses and their effector proteins, such as heat shock protein 70 (Hsp70), are the most prominent. Due to its popular medicinal use, which has led to depletion of its natural habitats, R. rosea is now considered as endangered in most parts of the world. Conservation, cultivation and micropropagation are all implemented as potential preservation strategies. A number of in vitro systems of R. rosea are being developed as sources of pharmaceutically valuable secondary metabolites. These are greatly facilitated by advances in elucidation of the biosynthetic pathways and the enzymes, which catalyse the production of these secondary metabolites in the plant. In addition, biotechnological approaches show promise towards achieving sustainable production of R. rosea secondary metabolites.</p

    Initial experience of a large, self-expanding, and fully recapturable transcatheter aortic valve: The UK & Ireland Implanters' registry.

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    OBJECTIVES: The UK & Ireland Implanters' registry is a multicenter registry which reports on real-world experience with novel transcatheter heart valves. BACKGROUND: The 34 mm Evolut R transcatheter aortic valve is a self-expanding and fully recapturable transcatheter aortic valve, designed to treat patients with a large aortic annulus. METHODS: Between January 2017 and April 2018, clinical, procedural and 30-day outcome data were prospectively collected from all patients receiving the 34 mm Evolut R valve across 17 participating centers in the United Kingdom and Ireland. The primary efficacy outcome was the Valve Academic Research Consortium-2(VARC-2)-defined endpoint of device success. The primary safety outcome was the VARC-2-defined composite endpoint of early safety at 30 days. RESULTS: A total of 217 patients underwent attempted implant. Mean age was 79.5 ± 8.8 years and Society of Thoracic Surgeons Predicted Risk of Mortality Score 5.2% ± 3.4%. Iliofemoral access was used in 91.2% of patients. Device success was 79.7%. Mean gradient was 7.0 ± 4.6 mmHg and effective orifice area 2.0 ± 0.6 cm2 . Paravalvular regurgitation was more than mild in 7.2%. A new permanent pacemaker was implanted in 15.7%. Early safety was demonstrated in 91.2%. At 30 days, all-cause mortality was 3.2%, stroke 3.7%, and major vascular complication 2.3%. CONCLUSIONS: Real-world experience of the 34 mm Evolut R transcatheter aortic valve demonstrated acceptable procedural success, safety, valve function, and incidence of new permanent pacemaker implantation

    Whose knowledge, whose voices? Power, agency and resistance in disability studies for the global south

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    Meekosha (2011) maintains that research and theories about disability derive mainly from the global North. Disability Studies rarely include non-metropolitan thinkers. Even when they do, these studies tend to be seen as context specific, and the social theories which emanate from these studies are rarely refered to in research theorizing disability in the North. This chapter sets out to investigate how this one way transfer of knowledge affects the way Disability Studies is conceptualised - whose experiences are incorporated within these studies; and whose are left out. Multilateral debate and dialogue between Disability Studies academics and activists in different locations around the world would help add on to the knowledge already available in the field, while keeping others informed about what is taking place in 'similar' situations elsewhere.peer-reviewe
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