220 research outputs found

    A transferable model for adsorption in MOFs with unsaturated metal sites

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    The number of newly discovered Metal-Organic Frameworks is growing exponentially. Molecular simulation is becoming increasingly important to screen large databases of structures and identify potential candidates for challenging gas separations, but such efforts rely on the availability of accurate molecular models that can predict adsorption in a wide range of different MOFs. MOFs with co-ordinatively unsaturated sites (CUS) pose particular problems because standard force fields are unable to describe their specific interactions with certain adsorbates. In this paper, we demonstrate that our previous approach to describe adsorption in open metal sites, based on a combination of classical Monte Carlo simulations and quantum-mechanical Density Functional Theory calculations, is transferable to several Cu-containing MOFs. By fitting the parameters of our model to match adsorption energies of ethylene on HKUST-1 and transferring them to the Cu-paddlewheel units of other MOFs, we have obtained predictions in good agreement with experimental adsorption measurements. Where agreement is not as satisfactory, we show that this can be explained by limited accessibility or diffusion through the pore network. For one particular MOF, UMCM-150, we show that separate parameters need to be used for the Cu-trimer unit, for which the interaction energies with ethylene are much lower than in the Cu-paddlewheel. Overall, our approach demonstrates that the specific CUS interactions in MOFs can be parameterised separately from other interaction types, such as van der Waals, thus opening the way for the development of an accurate and fully transferable force field for this class of materials

    Coriolus versicolor biomass increases dendritic arborization of newly-generated neurons in mouse hippocampal dentate gyrus

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    Brain cognitive reserve refers to the ability of the brain to manage different challenges that arise throughout life, making it resilient to neuropathology. Hippocampal adult neurogenesis has been considered to be a relevant contributor for brain cognitive reserve and brain plasticity. Coriolus versicolor (CV), a common healthful mushroom, has been receiving increasing attention by its antitumoral, anti-inflammatory, antioxidant, antibacterial, and immunomodulatory properties, including in the hippocampus. Herein, we evaluated whether CV biomass oral administration for 2.5 months enhances hippocampal neurogenic reserve under normal/physiological conditions, by quantifying hippocampal dentate gyrus (DG) granular cell layer (GCL) and subgranular zone (SGZ) volumes, proliferation, number and dendritic complexity features of hippocampal newly-generated neurons. We also analyzed β-catenin levels in DG newly-generated immature neurons, because it plays a major role in neurogenesis. Although no differences were observed in the volume of GCL and SGZ layers, in proliferation and in the number of newly-generated neurons of controls and CV-administered mice, we found that CV administration promotes a significant increase in dendritic length and branching and total dendritic volume of immature neurons, suggesting a positive effect of oral CV administration in the hippocampal neurogenic reserve. We also observed that β-catenin levels are increased both in the nucleus and cytoplasm of DG immature neurons, suggesting that Wnt/β-catenin signalling may play an important role in the CV positive effect on the differentiation of these cells. These data unveil a so far unexplored neurogenic potential of CV supplementation, which emerges as a possible preventive strategy for different neurological conditions.This work was supported by Mycology Research Laboratories, Ltd. This work was financed by the European Regional Development Fund (ERDF), through the Centro 2020 Regional Operational Programme under projects CENTRO-01-0145-FEDER-000012-HealthyAging2020 and CENTRO-01-0145-FEDER-000008 - BrainHealth 2020, and through the COMPETE 2020 - Operational Programme for Competitiveness and Internationalisation and Portuguese national funds via FCT – Fundação para a Ciência e a Tecnologia, under project POCI-01-0145-FEDER-007440 and Strategic Project 2015- UID/NEU/04539/2013. EF and SIM are holders of FCT postdoctoral grant (SFRH/BPD/86551/2012 and SFRH/BPD/99219/2013, respectively). J.V. salary was supported by an Ikerbasque Research Fellow grant

    Double shunt technique for hybrid palliation of hypoplastic left heart syndrome: a case report

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    We report a technique to palliate hypoplastic left heart syndrome, with no PDA stenting, but with double polytetrafluoroethylene shunt from pulmonary artery to ascending and descending aorta by combined thoracotomies. A 30-day-old female was operated with this technique. Five months after first operation, the child was submitted to Norwood/Glenn operation. Good hemodinamic recovery and initial clinical evolution was observed. The child was extubated in 8th post operatory day and reentubated in the next day due to pulmonary infection. Despite antibiotic treatment, the child died after systemic infectious complications

    Impact-parameter dependent nuclear parton distribution functions: EPS09s and EKS98s and their applications in nuclear hard processes

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    We determine the spatial (impact parameter) dependence of nuclear parton distribution functions (nPDFs) using the AA-dependence of the spatially independent (averaged) global fits EPS09 and EKS98. We work under the assumption that the spatial dependence can be formulated as a power series of the nuclear thickness functions TAT_A. To reproduce the AA-dependence over the entire xx range we need terms up to [TA]4[T_A]^4. As an outcome, we release two sets, EPS09s (LO, NLO, error sets) and EKS98s, of spatially dependent nPDFs for public use. We also discuss the implementation of these into the existing calculations. With our results, the centrality dependence of nuclear hard-process observables can be studied consistently with the globally fitted nPDFs for the first time. As an application, we first calculate the LO nuclear modification factor RAA1jetR^{1jet}_{AA} for primary partonic-jet production in different centrality classes in Au+Au collisions at RHIC and Pb+Pb collisions at LHC. Also the corresponding central-to-peripheral ratios RCP1jetR_{CP}^{1jet} are studied. We also calculate the LO and NLO nuclear modification factors for single inclusive neutral pion production, RdAuπ0R_{dAu}^{\pi^0}, at mid- and forward rapidities in different centrality classes in d+Au collisions at RHIC. In particular, we show that our results are compatible with the PHENIX mid-rapidity data within the overall normalization uncertainties given by the experiment. Finally, we show our predictions for the corresponding modifications RpPbπ0R_{pPb}^{\pi^0} in the forthcoming p+Pb collisions at LHC.Comment: 36 page

    Impact of cardiovascular risk factors on the clinical presentation and survival of pulmonary embolism without identifiable risk factor

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    Background: The nature of pulmonary embolism (PE) without identifiable risk factor (IRF) remains unclear. The objective of this study is to investigate the potential relationship between cardiovascular risk factors (CVRFs) and PE without IRF (unprovoked) and assess their role as markers of disease severity and prognosis. Methods: A case-control study was performed of patients with PE admitted to our hospital [2010-2019]. Subjects with PE without IRF were included in the cohort of cases, whereas patients with PE with IRF were allocated to the control group. Variables of interest included age, active smoking, obesity, and diagnosis of arterial hypertension, dyslipidemia or diabetes mellitus. Results: A total of 1,166 patients were included in the study, of whom 64.2% had PE without IRF. The risk for PE without IRF increased with age [odds ratio (OR): 2.68; 95% confidence interval (CI): 1.95-3.68], arterial hypertension (OR: 1.63; 95% CI: 1.27-2.07), and dyslipidemia (OR: 1.63; 95% CI: 1.24-2.15). The risk for PE without IRF was higher as the number of CVRF increased, being 3.99 (95% CI: 2.02-7.90) for subjects with >/=3 CVRF. The percentage of high-risk unprovoked PE increased significantly as the number of CVRF rose [0.6% for no CVRF; 23.8% for a CRF, P/=3, P<0.001 (OR: 14.1; 95% CI: 4.06-49.4)]. No significant differences were observed in 1-month survival between cases and controls, whereas differences in 24-month survival reached significance. Conclusions: A relationship was observed between CVRF and PE without IRF, as the risk for unprovoked PE increased with the number of CVRF. In addition, the number of CVRF was associated with PE without IRF severity, but not with prognosis

    Ataxin-3 phosphorylation decreases neuronal defects in spinocerebellar ataxia type 3 models

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    Different neurodegenerative diseases are caused by aberrant elongation of repeated glutamine sequences normally found in particular human proteins. Although the proteins involved are ubiquitously distributed in human tissues, toxicity targets only defined neuronal populations. Changes caused by an expanded polyglutamine protein are possibly influenced by endogenous cellular mechanisms, which may be harnessed to produce neuroprotection. Here, we show that ataxin-3, the protein involved in spinocerebellar ataxia type 3, also known as Machado-Joseph disease, causes dendritic and synapse loss in cultured neurons when expanded. We report that S12 of ataxin-3 is phosphorylated in neurons and that mutating this residue so as to mimic a constitutive phosphorylated state counters the neuromorphologic defects observed. In rats stereotaxically injected with expanded ataxin-3–encoding lentiviral vectors, mutation of serine 12 reduces aggregation, neuronal loss, and synapse loss. Our results suggest that S12 plays a role in the pathogenic pathways mediated by polyglutamine-expanded ataxin-3 and that phosphorylation of this residue protects against toxicity

    Impact of amendments on the physical properties of soil under tropical long-term no till conditions

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    Tropical regions have been considered the world's primary agricultural frontier; however, some physico-chemical deficiencies, such as low soil organic matter content, poor soil structure, high erodibility, soil acidity, and aluminum toxicity, have affected their productive capacity. Lime and gypsum are commonly used to improve soil chemical fertility, but no information exists about the long-term effects of these products on the physical attributes and C protection mechanisms of highly weathered Oxisols. A field trial was conducted in a sandy clay loam (kaolinitic, thermic Typic Haplorthox) under a no-tillage system for 12 years. The trial consisted of four treatments: a control with no soil amendment application, the application of 2.1 Mg ha-1 phosphogypsum, the application of 2.0 Mg ha-1 lime, and the application of lime + phosphogypsum (2.0 + 2.1 Mg ha-1, respectively). Since the experiment was established in 2002, the rates have been applied three times (2002, 2004, and 2010). Surface liming effectively increased water-stable aggregates > 2.0 mm at a depth of up to 0.2 m; however, the association with phosphogypsum was considered a good strategy to improve the macroaggregate stability in subsoil layers (0.20 to 0.40 m). Consequently, both soil amendments applied together increased the mean weight diameter (MWD) and geometric mean diameter (GMD) in all soil layers, with increases of up to 118 and 89%, respectively, according to the soil layer. The formation and stabilization of larger aggregates contributed to a higher accumulation of total organic carbon (TOC) on these structures. In addition to TOC, the MWD and aggregate stability index were positively correlated with Ca2+ and Mg2+ levels and base saturation. Consequently, the increase observed in the aggregate size class resulted in a better organization of soil particles, increasing the macroporosity and reducing the soil bulk density and penetration resistance. Therefore, adequate soil chemical management plays a fundamental role in improving the soil's physical attributes in tropical areas under conservative management and highly affected by compaction caused by intensive farming
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