14,249 research outputs found

    Fungal dysbiosis predicts the diagnosis of pediatric Crohn's disease

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    AIM: To investigate the accuracy of fungal dysbiosis in mucosa and stool for predicting the diagnosis of Crohn’s disease (CD). METHODS: Children were prospectively enrolled in two medical centers: one university hospital and one private gastroenterology clinic in the city of Riyadh, Kingdom of Saudi Arabia. The children with confirmed diagnosis of CD by standard guidelines were considered cases, and the others were considered non-inflammatory bowel disease controls. Mucosal and stool samples were sequenced utilizing Illumina MiSeq chemistry following the manufacturer’s protocols, and abundance and diversity of fungal taxa in mucosa and stool were analyzed. Sparse logistic regression was used to predict the diagnosis of CD. The accuracy of the classifier was tested by computing the receiver operating characteristic curves with 5-fold stratified cross-validation under 100 permutations of the training data partition and the mean area under the curve (AUC) was calculated. RESULTS: All the children were Saudi nationals. There were 15 children with CD and 20 controls. The mean age was 13.9 (range: 6.7-17.8) years for CD children and 13.9 (3.25-18.6) years for controls, and 10/15 (67%) of the CD and 13/20 (65%) of the control subjects were boys. CD locations at diagnosis were ileal (L1) in 4 and colonic (L3) in 11 children, while CD behavior was non-stricturing and non-penetrating (B1) in 12 and stricturing (B2) in 3 children. The mean AUC for the fungal dysbiosis classifier was significantly higher in stools (AUC = 0.85 ± 0.057) than in mucosa (AUC = 0.71 ± 0.067) (P < 0.001). Most fungal species were significantly more depleted in stools than mucosal samples, except for Saccharomyces cerevisiae and S. bayanus, which were significantly more abundant. Diversity was significantly more reduced in stools than in mucosa. CONCLUSION: We found high AUC of fungal dysbiosis in fecal samples of children with CD, suggesting high accuracy in predicting diagnosis of CD. Key Words: Fungiome, Mycobiome, Crohn’s disease, Inflammation, Saudi children Core tip: We found high accuracy of fungal dysbiosis in predicting diagnosis of Crohn’s disease (CD), a finding similar to bacterial dysbiosis. However, the higher area under the curve for the fungal dysbiosis classifier in stool (0.85 ± 0.057) than in mucosa (0.71 ± 0.067) (P < 0.001), contrasts with bacterial studies, suggesting higher accuracy of stool samples. Although the clinical application of this finding is limited at present by the high cost of fungal analysis, such information is important from a scientific viewpoint, to increase the understanding of the role of fungal flora in CD and to stimulate further studies.The authors extend their appreciations to the Deanship of Scientific Research at King Saud University in Riyadh, Kingdom of Saudi Arabia for funding this work through Research Group No [RGP-1436-007]. This work was also supported by a grant from the Simons Foundation [No. 409704] to Kirill Korolev) and by the startup fund from Boston University to Kirill Korolev. Simulations were carried out on Shared Computing Cluster at Boston University. Rajita Menon was partially supported by a Hariri Graduate Fellowship from Boston University. Harland Winter, MD received support from Martin Schlaff and the Diane and Dorothy Brooks Foundation. (RGP-1436-007 - King Saud University in Riyadh, Kingdom of Saudi Arabia; 409704 - Simons Foundation; Boston University; Hariri Graduate Fellowship from Boston University; Diane and Dorothy Brooks Foundation)Published versio

    Extent of Liability of Heirs for deceased's Debts in Jordanian Civil Law

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    I have dealt in this  research  titled " Extent of Liability of Heirs for deceased’s Debts in Jordanian Civil Law" whereby it appears that liability of heirs for deceased’s debt is limited to what they received from his estate, it also appears that not everything inherited by heirs will be considered part of the estate. I have also addressed the time ownership of the estate passes to heirs and the jurisprudential dispute about it as well as the position of the Civil Law. It is evidenced by provisions that estate passes to heirs upon the deceased person’s death. I have also dealt with the effects and consequences of determining the time the ownership of estate passes to heirs, it appeared that there are important results and consequences for determining the time the estate is passed to heirs. I have also dealt with the rule of the deceased's postponed debt, and the rule of dispositions of an indebted estate property by the heirs before and after its division, and the discrepancy between the estate creditors' rights, and the rights of those disposed to by heirs or one of them. The principle is in the primacy of attachment by the creditors, or the registration of the disposition by the persons disposed to in the real estate, as for movable property, the principle is in the possession whenever it is bona fide and has a valid ground. Keywords: Liability of heirs, deceased’s debts

    High-Order Hybrid Stratified Sampling: Fast Uniform-Convergence Fourier Transform Estimation

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    This paper considers the problem of estimating the Fourier transform of continuous-time signals from N nonuniformly collected observations. Here, we introduce a new class of Hybrid Stratified sampling scheme in conjunction with a suitable estimator, which can provide the rate of convergence of order \u1d7cf/\u1d475(\u1d7d0\u1d472+\u1d7d1) in the mean-square sense, for signals with \u1d472+\u1d7cf continuous derivatives. Most importantly, it is shown that this rate is not only faster, but also uniform and independent of the analysed frequency (unlike) compared with other existing random-sampling-based techniques. In this paper, we establish the statistical properties of the proposed approach and illustrate its performance analytically as well as numerically

    The law governing oil concession agreements and the permanent sovereignty of states over their natural resources : with special reference to Islamic Shari'ah law

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    Tese de doutoramento em Engenharia Mecânica, na área de Superfícies, apresentada ao Departamento de Engenharia Mecânica da Faculdade de Ciências e Tecnologia da Universidade de CoimbraO desenvolvimento de superfícies antibacterianas representa um desafio atual em diferentes aplicações industriais, nomeadamente, dispositivos médicos, embalagens alimentares, têxteis e sistemas de tratamento de água. A maioria das bactérias existe em biofilmes que aderem fortemente a diferentes tipos de superfícies uma vez que esta adesão representa um mecanismo estratégico de sobrevivência. O fenómeno da adesão e colonização microbiana resulta na falha de diferentes dispositivos e componentes utilizados nas aplicações acima mencionadas, tendo como consequência perdas económicas elevadas e representando também um problema de saúde pública quando se tratam de aplicações como dispositivos médicos ou embalagens alimentares. Neste sentido, ao longo das últimas décadas o desenvolvimento de superfícies antibacterianas tem sido considerada uma estratégia emergente no desenvolvimento de materiais mais eficientes a serem aplicados em diferentes sectores. O objetivo da presente tese consiste no desenvolvimento e caracterização de revestimentos nanocompósitos multifuncionais baseados em revestimentos de carbono amorfo dopado com nanopartículas de prata (Ag/a-C) para potencial aplicação em superfícies antibacterianas. A Ag é atualmente considerada como o agente bactericida mais promissor e eficiente, sendo que as nanopartículas de prata representam o material mais comercializado na área da nanotecnologia. A estratégia de modificação superficial com revestimentos baseados em carbono amorfo (a-C) tem-se tornado popular do ponto de vista industrial essencialmente, devido entre outras propriedades, à sua resistência ao desgaste tribológico excecional, que permite combinar uma elevada dureza com um baixo coeficiente de atrito, elevada estabilidade química, resistência à corrosão e biocompatibilidade em diferentes aplicações biomédicas. Na atualidade os revestimentos de a-C são utilizados em diferentes aplicações industriais nomeadamente dispositivos médicos, lâminas de barbear e diferentes componentes mecânicos sujeitos a elevado desgaste tribológico. Neste sentido, a combinação das propriedades intrínsecas destes materiais pode ser considerada uma abordagem promissora para o desenvolvimento de revestimentos multifuncionais, os quais podem ser aplicados em diferentes produtos, nomeadamente, dispositivos médicos. Na presente tese os revestimentos nanocompósitos de Ag/a-C são depositados por dois métodos distintos: (i) pulverização catódica em magnetrão e (ii) combinação da pulverização catódica em magnetrão para deposição da camada de a-C e condensação em atmosfera inerte para a incorporação simultânea de nanopartículas de Ag na matrix de carbono. Os métodos acima mencionados são comparados em relação à uniformidade dos revestimentos depositados, permitindo efetuar a escolha do método de deposição mais eficaz (pulverização catódica em magnetrão). Os revestimentos nanocompósitos de Ag/a-C são caraterizados relativamente à sua estrutura, estabilidade termodinâmica em condições ambientais e propriedades funcionais (comportamento tribológico e atividade antibacteriana). O trabalho central da tese é focado na caraterização de revestimentos Ag/a-C contendo 20% at. de Ag, com diferentes espessuras e diferentes estruturas em multicamada. Os resultados sugerem que os revestimentos Ag/a-C são instáveis mesmo em condições ambientais, sendo observado que a Ag é forma nanofibras entre as fronteiras das colunas, as quais recobrem a superfície do revestimento poucas semanas após a produção. O processo de formação de nanofibras é promovido pela humidade, sendo que, as partículas crescem através de um processo de coalescência. As propriedades funcionais sugerem que os revestimentos Ag/a-C são promissores do ponto de vista de actividade antibacteriana, a qual está relacionada com a sua ionização. Os testes tribológicos revelam que em ambiente não lubrificado a presença da Ag promove a degradação dos revestimentos a-C, contudo, em meios biológicos que simulam o líquido sinovial, presente nas articulações da anca, o comportamento tribológico é semelhante aos revestimentos a-C.The development of antibacterial surfaces represents a great challenge in different industrial applications, namely, medical devices, food packaging industry, textiles or aquatic flow systems. Most of living bacteria are found to grow in biofilms which strongly adhere to different types of surfaces, where they find a strategic survival mechanism. This phenomena leads to the failure of different types of materials used in the above mentioned applications, which represent a huge economic loss and also an public health concern when it comes to fields such as medical devices or food packages. In this sense over the past years the development of antibacterial surfaces has been pointed as a new strategy for the development of more efficient materials to be applied in different industrial sectors. This thesis deals with the development and characterization of multifunctional amorphous carbon coatings doped with Ag nanoparticles (Ag/a-C) for potential application in antibacterial surfaces. Ag is nowadays pointed as the most effective bactericidal agent, which is already the leading material in nanotechnology market. In other hand, the strategy of surface modification with amorphous carbon (a-C) coatings has become very popular due to its unique tribological properties, which allow to combine high hardness and low friction coefficient, chemical inertness and biocompatibility, just to name some of its properties, which has prompted its use in different applications, namely, medical devices, razorblades, mechanical components with enhanced tribological performance. In this sense, the incorporation of Ag nanoparticles within a-C coatings can be regarded as a promising approach for achieving multifunctional properties in different applications, such as medical devices. In the present thesis Ag doped a-C nanocomposite coatings are deposited by two alternative deposition methods based on physical routes: (i) dual magnetron sputtering and (ii) combination of magnetron sputtering for a-C layer deposition and plasma gas condensation for Ag nanoparticles in-situ incorporation in the host matrix. The above mentioned deposition methods are compared with respect to the uniformity in the deposition of large surface areas, which allowed to select the most suitable deposition method (magnetron sputtering). The Ag/a-C nanocomposite coatings are characterized with respect to their structure, thermodynamic stability at room temperature conditions and functional properties (antibacterial activity and tribological behavior). The core thesis work is focused in Ag/a-C nanocomposite coatings containing 20 at.% of Ag, with different thicknesses/morphologies and different multilayer structures. The results suggest that Ag/a-C coatings are unstable even at atmospheric conditions, being found that Ag grows within the coatings column boundaries forming Ag nanowhiskers, which cover the coatings surface few weeks after deposition. The process of Ag nanowhiskering is found to be promoted by the humidity, being found that particles grew through a coalescence process. The functional properties suggest that Ag/a-C coatings are promising in terms of antibacterial activity, which is correlated with the Ag ionization. The tribological tests reveal that in dry sliding condition Ag promotes a degradation in a-C coatings tribological properties; however, in biological medium simulating the synovial fluids, found in joint prosthesis, the tribological behavior is similar to the a-C layer.FCT - SFRH/BD/82472/201

    Kinetic and equilibrium studies of the reactions of some aromatic nitro compounds with metal alkoxides

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    Kinetic and equilibrium measurements have been made for σ-adduct formation from propoxide ions in propan-1-ol with 1,3,5-trinitrobenzene and a series of l-propoxy-2,4-dinitro-6-x-benzenes ( x = NO(_2), Cl, CO(_2)Pr, H).The results are compared with those for similar additions of other alkoxide ions. There is evidence for strong association with sodium ions o f the 1,1-dipropoxy adducts, but adducts formed by base additions at unsubstituted ring positions are not strongly associated. In the nucleophilic substitution reaction with l-chloro-2,4-dinitrobenzene free propoxide ions show greater reactivity than sodium propoxide ion pairs. Rate and equilibrium studies are reported for the reactions of three aromatic nitro-compounds with tetramethylarrmonium hydroxide in t-butyl alcohol water mixtures. There is evidence that the reactive nucleophile is t he hydroxide ion rather than the t-butoxide ion. The reaction of 1,3,5-trinitrobenzene in this system leads to a σ-adduct, while l-chloro-2,4-dinitrobenzene gives 2,4-dinitrophenol. That the rates of both these reactions falls rapidly with increasing water content is attributed mainly to the good solvation of the hydroxide ion by water. In contrast the rate of formation of picric acid from picryl chloride increases with water content due to initial formation of the 3-hydroxy adduct. Similar studies have been made using sodium and/or potassium butoxide The interpretation here is complicated by association with anions of the alkali metal cations. In the presence of methoxide ions in methanol 2-methoxy-3,5-dinitrobenzoic acid gives a a-adduct. Using this reaction, acidity functions for lithium, sodium and potassium methoxide solutions have been defined. The observed b a sicity order : sodium methoxide > potassium methoxide > lithium methoxide may derive from specific interactions of the alkali cations with the σ-adduct. Using U.V./visible data the reversible equilibria between 1-x-2,4,6-trinitrobenzenes ( x = NMe(_2), NHMe, NH(_2), OMe or CCH(_2)CH(_2)O) and alkali metal methoxides have been investigated. Usually 1:1, 1:2 and 1:3 interactions are observed. One conclusion is that in general 1:2 and 1:3 adducts associate more strongly with sodium ions than with potassium ions or with lithium ions
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