52 research outputs found

    Modelling adsorption using an augmented two-dimensional statistical associating fluid theory: 2D-SAFT-VR Mie

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    We present an extension of the SAFT-VR Mie approach to model adsorption of molecular fluids based on a two-dimensional (2D) approximation to describe the adsorbed fluid. Analytical results are provided for the first- and second-order perturbation terms of the free energy for the 2D system. The adsorption model is based on the assumption that the particle pair interactions in the adsorbed and bulk phases are described with the same Mie potential exponents Ī»a and Ī»r, in contrast with the square-well version of the 2D-SAFT-VR approach in which it is considered necessary to modify the attractive ranges of the SW interactions. This important difference between the two approaches leads to a reduction in the number of molecular parameters to be determined. In order to demonstrate the performance of the 2D-SAFT-VR Mie approach, we present results for the the modelling of carbon dioxide (CO2) and methane (CH4) adsorbed onto dry coal

    From logical forms to SPARQL query with GETARUNS

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    We present a system for Question Answering which computes a prospective answer from Logical Forms produced by a full-fledged NLP for text understanding, and then maps the result onto schemata in SPARQL to be used for accessing the Semantic Web. As an intermediate step, and whenever there are complex concepts to be mapped, the system looks for a corresponding amalgam in YAGO classes. It is just by the internal structure of the Logical Form that we are able to produce a suitable and meaningful context for concept disambiguation. Logical Forms are the final output of a complex system for text understanding - GETARUNS - which can deal with different levels of syntactic and semantic ambiguity in the generation of a final structure, by accessing computational lexical equipped with sub-categorization frames and appropriate selectional restrictions applied to the attachment of complements and adjuncts. The system also produces pronominal binding and instantiates the implicit arguments, if needed, in order to complete the required Predicate Argument structure which is licensed by the semantic component

    Preexisting Depression and Ambulatory Status After Stroke: Florida-Puerto Rico Collaboration to Reduce Stroke Disparities

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    OBJECTIVE: Stroke is a global public health burden, and therefore it is critical to identify modifiable risk factors to reduce stroke incidence and improve outcomes. Depression is such a risk factor; however, the association between preexisting depression and stroke outcomes, such as independent ambulation, is not well studied, especially among racial-ethnic minority groups. To address this gap in the literature, effects of preexisting depression on ambulatory status at hospital discharge after stroke were evaluated among individuals participating in the racially and ethnically diverse Florida-Puerto Rico Collaboration to Reduce Stroke Disparities project. METHODS: Data were analyzed from a total of 42,031 ischemic stroke patients, who were independently ambulatory prior to their stroke, after discharge from 84 hospitals between 2014 and 2017. Preexisting depression was confirmed by medical history or antidepressant medication use. Multilevel multivariate logistic regression analyses were used to assess the association of preexisting depression with independent ambulation at hospital discharge. Effects of sex and race-ethnicity on this association were examined. RESULTS: Of 42,031 participants (meanĀ±SD age=70.4Ā±14.2 years; 48% were female; race-ethnicity: 16% Black, 12% Hispanic living in Florida, and 7% Hispanic living in Puerto Rico), 6,379 (15%) had preexisting depression. Compared with participants without depression, those with preexisting depression were older, were more likely to be female and non-Hispanic White, and had a greater burden of vascular risk factors or comorbid conditions. Independent ambulation at hospital discharge was less frequent among women, Black participants, and individuals with vascular risk factors or comorbid conditions. In multivariate models, preexisting depression decreased the likelihood of independent ambulation at discharge (odds ratio=0.88, 95% CI=0.81, 0.97). No interactions were found between preexisting depression and race-ethnicity or sex. CONCLUSIONS: Preexisting depression was independently associated with dependent ambulation at hospital discharge after stroke, regardless of sex and race-ethnicity. Treating depression may contribute to primary stroke prevention and could improve ambulatory status at discharge

    In vitro inhibitory activities of selected Australian medicinal plant extracts against protein glycation, angiotensin converting enzyme (ACE) and digestive enzymes linked to type II diabetes

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    This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background There is a need to develop potential new therapies for the management of diabetes and hypertension. Australian medicinal plants collected from the Kuuku Iā€™yu (Northern Kaanju) homelands, Cape York Peninsula, Queensland, Australia were investigated to determine their therapeutic potential. Extracts were tested for inhibition of protein glycation and key enzymes relevant to the management of hyperglycaemia and hypertension. The inhibitory activities were further correlated with the antioxidant activities. Methods Extracts of five selected plant species were investigated: Petalostigma pubescens, Petalostigma banksii, Memecylon pauciflorum, Millettia pinnata and Grewia mesomischa. Enzyme inhibitory activity of the plant extracts was assessed against Ī±-amylase, Ī±-glucosidase and angiotensin converting enzyme (ACE). Antiglycation activity was determined using glucose-induced protein glycation models and formation of protein-bound fluorescent advanced glycation endproducts (AGEs). Antioxidant activity was determined by measuring the scavenging effect of plant extracts against 1, 1-diphenyl-2-picryl hydrazyl (DPPH) and using the ferric reducing anti-oxidant potential assay (FRAP). Total phenolic and flavonoid contents were also determined. Results Extracts of the leaves of Petalostigma banksii and P. pubescens showed the strongest inhibition of Ī±-amylase with IC50 values of 166.50ā€‰Ā±ā€‰5.50 Ī¼g/mL and 160.20ā€‰Ā±ā€‰27.92 Ī¼g/mL, respectively. The P. pubescens leaf extract was also the strongest inhibitor of Ī±-glucosidase with an IC50 of 167.83ā€‰Ā±ā€‰23.82 Ī¼g/mL. Testing for the antiglycation potential of the extracts, measured as inhibition of formation of protein-bound fluorescent AGEs, showed that P. banksii root and fruit extracts had IC50 values of 34.49ā€‰Ā±ā€‰4.31 Ī¼g/mL and 47.72ā€‰Ā±ā€‰1.65 Ī¼g/mL, respectively, which were significantly lower (pā€‰<ā€‰0.05) than other extracts. The inhibitory effect on Ī±-amylase, Ī±-glucosidase and the antiglycation potential of the extracts did not correlate with the total phenolic, total flavonoid, FRAP or DPPH. For ACE inhibition, IC50 values ranged between 266.27ā€‰Ā±ā€‰6.91 to 695.17ā€‰Ā±ā€‰15.38 Ī¼g/mL. Conclusions The tested Australian medicinal plant extracts inhibit glucose-induced fluorescent AGEs, Ī±-amylase, Ī±-glucosidase and ACE with extracts of Petalostigma species showing the most promising activity. These medicinal plants could potentially be further developed as therapeutic agents in the treatment of hyperglycaemia and hypertension

    An investigation of free-energy-averaged (coarse-grained) potentials for fluid adsorption on heterogeneous solid surfaces

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    Coarse-grained, two-body fluidā€“solid potentials provide a simple way to describe the interaction between a fluid molecule and a solid in adsorption theories, and also a means to reduce the computational expense in molecular simulations, compared to those employing full atomistic detail. Here we investigate the applicability of a recently proposed mapping procedure to obtain free-energy-averaged (FEA) fluidā€“solid interactions for fluids on various heterogeneous surfaces. Methane and graphite are chosen as the fluid and the solid, respectively, and the surface graphene layer is modified to create chemical and geometrical heterogeneities; for the latter surfaces, the FEA mapping is appropriately modified to account for vacancies. Adsorption isotherms and fluid density profiles are obtained by performing grand canonical Monte Carlo (GCMC) simulations for explicit-solid and FEA-potential representations, and are compared to gain insights about the applicability and limitations of the FEA potentials. For solids with homogeneous and chemically heterogeneous surfaces, adsorption isotherms and density profiles obtained using FEA potentials are in good agreement with those obtained using an explicit-solid representation. For surfaces containing vacancies, isotherms and density profiles obtained using the unmodified FEA potential differ significantly from their explicit-surface analogues. When using the FEA potential obtained with the modified mapping procedure some deviations are still seen at very high pressure, however, at low to moderate pressures, agreement is, once again, good

    Monte Carlo molecular simulation study of carbon dioxide sequestration into dry and wet calcite pores containing methane

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    We perform grand canonical Monte Carlo (GCMC) simulations to study the adsorption of carbon dioxide in a calcite slit pore. The injection of carbon dioxide is simulated by increasing the chemical potential of carbon dioxide, which allows for an investigation of adsorption under varying carbon dioxide loadings. The study is carried out for three different environments: an empty pore; a pore containing methane; and a pore containing methane with trace amounts of water. We systematically investigate the impact of the presence of these other fluids on carbon dioxide adsorption. We study the influence of carbon dioxide loading on fluid density in the pore and examine individual fluid-density profiles (in the direction normal to the fluidā€“solid interface). The order of fluid adsorption affinity to the surface is found to be water > carbon dioxide > methane. The interpretation of our results is informed by the examination of free-energy-averaged fluidā€“substrate potentials, which are computed independently from the simulations. Our observations suggest that ignoring the presence of water could lead to overestimation not only of methane availability but also of carbon dioxide storage capacity in pores, with important consequences in, for example, modeling carbon dioxide sequestration in calcite-rich reservoirs. Ultimately, it is hoped that the molecular-level insights from this study will aid the multiscale modeling of reservoir fluids in the context of enhanced oil recovery and carbon dioxide sequestration

    Management of locally advanced soft tissue tumors with major vessel reconstruction - A case series

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    Management of soft tissue tumors in the advanced stage often precludes complete surgical resection in view of major vessel involvement and demands major amputation for tumor clearance. We present a series of patients presented with advanced tumor presentation by major vessel resection and reconstruction (using vein or synthetic graft) without compromising tumor clearance. This preserves the limb function without increasing the tumor recurrence rate
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