16,998 research outputs found
Preparation of ethylcellulose/methylcellulose blends by supercritical antisolvent precipitation
The supercritical antisolvent (SAS) techniquewas used to prepare ethyl cellulose/methyl cellulose blends, two biocompatible polymers commonly
used as drug carriers in controlled delivery systems. Ethyl cellulose is widely used as a drug carrier. The drug release of the delivery devices can
be controlled to some extent by addition of a water-soluble or water swellable polymer, such as methyl cellulose. This leads to the solubility
enhancement of poorly water-soluble molecules. SAS experiments were carried out at different operational conditions and microspheres with mean
diameters ranging from 5 to 30 m were obtained. The effect of CO2 and liquid flow, temperature and pressure on particle size and particle size
distribution was evaluated. The microspheres were precipitated from a mixture of dichloromethane (DCM) and dimethylsulfoxide (DMSO) (4:1
ratio). The best process conditions for this mixture were according to our study 40 ◦C and 80 bar
Perfil de progestinas fecais durante a gestação de veado-campeiro (ozotoceros bezoarticus) no Pantanal brasileiro.
A constante ameaça às populações de veado-campeiro (Ozotoceros bezoarticus) faz deste cervídeo uma espécie ameaçada de extinção, trazendo à tona a necessidade de mais estudos, principalmente relacionado à biologia e fisiologia reprodutiva. Sendo assim, os objetivos do trabalho foram: definir o padrão de excreção de progestágenos fecais durante a gestação do veado-campeiro e validar possível método não-invasivo para diagnóstico de gestação, com uso de análises endócrinas. Para isso, onze fêmeas da espécie foram capturadas, marcadas e receberam colares radiotransmissores no Pantanal, região da Nhecolândia. Elas foram acompanhadas mensalmente e tiveram sua fezes colhidas para caracterização hormonal da gestação, entre o período de agosto de 2008 a novembro de 2009. Foi observada a ocorrência de parto em sete fêmeas, as quais foram utilizadas na caracterização endócrina da gestação. As dosagens das progestinas fecais foram feitas por ensaio imunoenzimático. Os níveis das progestinas fecais durante o início da gestação foram semelhantes aos períodos não-gestantes, com aumento progressivo a partir do segundo terço da gestação até o momento do parto, decaindo após esse período aos níveis não-gestantes. Os níveis de progestinas fecais acima de 6 ?g/g de fezes são sugestivos de gestação
The role of human resources on the economy: a study of the Balkan eu member states
In this paper we analyze the impact of the quality of human capital on the main economic indicators of South-Eastern Europe countries [SEE] at the NUTS 2 level. The subjects of this research are the human capital indicators of regional competitiveness. The quality of human capital depends largely on the age structure of the population and the quality of education. Those regions, which have the highest percentage of the working-age population and highly educated people, are able to achieve higher productivity and gain a competitive advantage over other regions. As main indicators of the quality of human capital we identified: population; persons aged 25-64 with tertiary education attainment; students in tertiary education and participation of adults aged 25-64 in education and training and human resources in science and technology. As main economic indicators, we identified: regional gross domestic product; employment and income of households. The aim of this paper is to determine whether there is a correlation between the indicators of the quality of human capital and economic indicators. As a main methodology we have used the correlation coefficient which shows interdependence of the analyzed indicators. As part of our analysis, we consider only EU member states that belong to the SEE countries: Slovenia, Croatia, Romania, Bulgaria and Greece. We conclude that in all countries there is a high multiple correlation coefficient between the indicators human resources in science and technology, number of students and employment.This paper is the result of the project No. 47007 III funded by the Ministry for Education, Science and Technological Development of Republic of Serbia
Tobacco rattle virus and its associated vector trichodorid nematodes in Portugal
Tobacco rattle virus (TRV, genus Tobravirus), transmitted by trichodorid nematodes, occurs as a wide range of serologically distinguishable strains that cause diseases in various economically important crops. The virus and its associated vector nematodes occur world-wide, being particularly prevalent in Europe and North America. In Portugal, an investigation is being conducted to identify TRV strains occurring in association with their natural vector species. The project has focused on potato growing areas in northern and central Portugal, with soil sampling biased in favour of areas where TRV-like symptoms have been reported. Nematodes were extracted from soil and phenotypically identified. TRV was recovered from nematodes in virus transmission studies, and identification confirmed using sap transmission tests, a leaf squash method with EM, ELISA, ISEM, and RT-PCR. Trichodorids were recovered frequently from potato fields, and the species identified were: Trichodorus lusitanicus, T. primitivus, Paratrichodorus anemones, P. hispanus, P. minor, P. pachydermus, also three new undescribed species and an unidentified Paratrichodorus species. TRV occurred in 4 of 58 (7%) soil samples in association with trichodorids: one in the North and the others in the centre of the country. Molecular characterisation of the TRV isolates and their associated vector trichodorids is presently in process
Defaults in bank loans to SMEs during the financial crisis
We investigate the role of (business) collateral and (personal) guarantees alongside small and medium enterprise (SME), lending bank and loan characteristics, macroeconomic conditions, sectors, and geographic locations while controlling for unobserved time effects in predicting default at the peak of the financial crisis. First, we find a positive relation between collateral and default, and a negative relation between guarantees and default. Second, we find a negative relation between the joint influence of collateral and high credit score, and a positive relation between the joint influence of collateral and low credit score and default. We also find a negative relation between the joint influence of guarantees and high credit score. These findings are relevant for SME policies aimed at facilitating access to credit, reducing the cost of borrowing, and decreasing default; risk management of banks; and the application of theories of financial economics in the context of a financial crisis.info:eu-repo/semantics/publishedVersio
Credit risk, owner liability and bank loan maturities during the global financial crisis
We relate credit risk and owners’ personal guarantees to bank loan maturities during the global financial crisis. The findings, which remain robust to reverse causality, show that firms rated as low risk, with a strong relationship with the bank, whose owners provided personal guarantees and with large loan sizes obtained longer maturities. Banks with larger nonperforming loans provided loans with shorter maturities. Firms with low and high risk ratings that provided owners’ personal guarantees obtained longer maturities. These findings shed additional light on the relationship between risk and loan maturities and the role of personal guarantees in reducing information asymmetries.info:eu-repo/semantics/acceptedVersio
Evaluation of commercial myxomatosis vaccines against recombinant myxoma virus (ha-MYXV) in Iberian hare and wild rabbit
Research Areas: Immunology ; Research & Experimental MedicineThe recent emergence of a new myxoma virus capable of causing disease in the Iberian hare (Lepus granatensis) has resulted in numerous outbreaks with high mortality leading to the reduction, or even the disappearance, of many local populations of this wild species in the Iberian Peninsula. Currently, the available vaccines that prevent myxomatosis in domestic rabbits caused by classic strains of myxoma virus have not been assessed for use in Iberian hares. The main objective of this study was to evaluate the efficacy of commercial rabbit vaccines in Iberian hares and wild rabbits against the natural recombinant myxoma virus (ha-MYXV), bearing in mind its application in specific scenarios where capture is possible, such as genetic reserves. The study used a limited number of animals (pilot study), 15 Iberian hares and 10 wild rabbits. Hares were vaccinated with Mixohipra-FSA vaccine (Hipra) and Mixohipra-H vaccine (Hipra) using two different doses, and rabbits were vaccinated with the Mixohipra-H vaccine or the Nobivac Myxo-RHD PLUS (MSD Animal Health) using the recommended doses for domestic rabbits. After the vaccination trials, the animals were challenged with a wild type strain of ha-MYXV. The results showed that no protection to ha-MYXV challenge was afforded when a commercial dose of Mixohipra-FSA or Mixohipra-H vaccine was used in hares. However, the application of a higher dose of Mixohipra-FSA vaccine may induce protection and could possibly be used to counteract the accelerated decrease of wild hare populations due to ha-MYXV emergence. The two commercial vaccines (Mixohipra-H and Nobivac Myxo-RHD PLUS) tested in wild rabbits were fully protective against ha-MYXV infection. This knowledge gives more insights into ha-MYXV management in hares and rabbits and emphasises the importance of developing a vaccine capable of protecting wild populations of Iberian hare and wild rabbit towards MYXV and ha-MYXV strainsinfo:eu-repo/semantics/publishedVersio
How Many Fractional Derivatives Are There?
Funding: This work was partially funded by National Funds through the FCT-Foundation for Science and Technology within the scope of the CTS Research Unit—Center of Technology and Systems/UNINOVA/FC /NOVA, under the reference UIDB/00066/2020, and also by FCT through IDMEC, under LAETA, project UID/EMS/50022/2020.
Publisher Copyright:
© 2022 by the authors. Licensee MDPI, Basel, Switzerland.In this paper, we introduce a unified fractional derivative, defined by two parameters (order and asymmetry). From this, all the interesting derivatives can be obtained. We study the one-sided derivatives and show that most known derivatives are particular cases. We consider also some myths of Fractional Calculus and false fractional derivatives. The results are expected to contribute to limit the appearance of derivatives that differ from existing ones just because they are defined on distinct domains, and to prevent the ambiguous use of the concept of fractional derivative.publishersversionpublishe
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