760 research outputs found

    Targeted classification of metal–organic frameworks in the Cambridge structural database (CSD)

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    Large-scale targeted exploration of metal–organic frameworks (MOFs) with characteristics such as specific surface chemistry or metal-cluster family has not been investigated so far. These definitions are particularly important because they can define the way MOFs interact with specific molecules (e.g. their hydrophilic/phobic character) or their physicochemical stability. We report here the development of algorithms to break down the overarching family of MOFs into a number of subgroups according to some of their key chemical and physical features. Available within the Cambridge Crystallographic Data Centre's (CCDC) software, we introduce new approaches to allow researchers to browse and efficiently look for targeted MOF families based on some of the most well-known secondary building units. We then classify them in terms of their crystalline properties: metal-cluster, network and pore dimensionality, surface chemistry (i.e. functional groups) and chirality. This dynamic database and family of algorithms allow experimentalists and computational users to benefit from the developed criteria to look for specific classes of MOFs but also enable users – and encourage them – to develop additional MOF queries based on desired chemistries. These tools are backed-up by an interactive web-based data explorer containing all the data obtained. We also demonstrate the usefulness of these tools with a high-throughput screening for hydrogen storage at room temperature. This toolbox, integrated in the CCDC software, will guide future exploration of MOFs and similar materials, as well as their design and development for an ever-increasing range of potential applications

    Automated echocardiographic detection of heart failure with preserved ejection fraction using artificial intelligence

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    Background: Detection of heart failure with preserved ejection fraction (HFpEF) involves integration of multiple imaging and clinical features which are often discordant or indeterminate. Objectives: We applied artificial intelligence (AI) to analyze a single apical four-chamber (A4C) transthoracic echocardiogram videoclip to detect HFpEF. Methods: A three-dimensional convolutional neural network was developed and trained on A4C videoclips to classify patients with HFpEF (diagnosis of HF, EF≥50%, and echocardiographic evidence of increased filling pressure; cases) versus without HFpEF (EF≥50%, no diagnosis of HF, normal filling pressure; controls). Model outputs were classified as HFpEF, no HFpEF, or non-diagnostic (high uncertainty). Performance was assessed in an independent multi-site dataset and compared to previously validated clinical scores. Results: Training and validation included 2971 cases and 3785 controls (validation holdout, 16.8% patients), and demonstrated excellent discrimination (AUROC:0.97 [95%CI:0.96-0.97] and 0.95 [0.93-0.96] in training and validation, respectively). In independent testing (646 cases, 638 controls), 94 (7.3%) were non-diagnostic; sensitivity (87.8%; 84.5-90.9%) and specificity (81.9%; 78.2-85.6%) were maintained in clinically relevant subgroups, with high repeatability and reproducibility. Of 701 and 776 indeterminate outputs from the HFA-PEFF and H2FPEF scores, the AI HFpEF model correctly reclassified 73.5 and 73.6%, respectively. During follow-up (median [IQR]:2.3 [0.5-5.6] years), 444 (34.6%) patients died; mortality was higher in patients classified as HFpEF by AI (hazard ratio [95%CI]:1.9 [1.5-2.4]). Conclusion: An AI HFpEF model based on a single, routinely acquired echocardiographic video demonstrated excellent discrimination of patients with versus without HFpEF, more often than clinical scores, and identified patients with higher mortality

    BDNF and NGF Signalling in Early Phases of Psychosis: Relationship with Inflammation and Response to Antipsychotics after 1 Year

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    Previous studies have indicated systemic deregulation of the proinflammatory or anti-inflammatory balance in individuals with first-episode psychosis (FEP) that persists 12 months later. To identify potential risk/protective factors and associations with symptom severity, we assessed possible changes in plasma levels of neurotrophins (brain-derived neurotrophic factor BDNF] and nerve growth factor NGF]) and their receptors in peripheral blood mononuclear cells (PBMCs). Expression of the 2 forms of BDNF receptors (active TrkB-FL and inactiveTrkB-T1) in PBMCs of FEP patients changed over time, TrkB-FL expression increasing by 1 year after diagnosis, while TrkB-T1 expression decreased. The TrkB-FL/TrkB-T1 ratio (hereafter FL/T1 ratio) increased during follow-up in the nonaffective psychosis group only, suggesting different underlying pathophysiological mechanisms in subgroups of FEP patients. Further, the expression of the main NGF receptor, TrkA, generally increased in patients at follow-up. After adjusting for potential confounders, baseline levels of inducible isoforms of nitric oxide synthase, cyclooxygenase, and nuclear transcription factor were significantly associated with the FL/T1 ratio, suggesting that more inflammation is associated with higher values of this ratio. Interestingly, the FL/T1 ratio might have a role as a predictor of functioning, a regression model of functioning at 1 year suggesting that the effect of the FL/T1 ratio at baseline on functioning at 1 year depended on whether patients were treated with antipsychotics. These findings may have translational relevance; specifically, it might be useful to assess the expression of TrkB receptor isoforms before initiating antipsychotic treatment in FEPs

    BDNF and NGF signalling in early phases of psychosis: relationship with inflammation and response to antipsychotics after a 1 year

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    Previous studies have indicated systemic deregulation of the proinflammatory or anti-inflammatory balance in individuals with first-episode psychosis (FEP) that persists 12 months later. To identify potential risk/protective factors and associations with symptom severity, we assessed possible changes in plasma levels of neurotrophins (brain-derived neurotrophic factor [BDNF] and nerve growth factor [NGF]) and their receptors in peripheral blood mononuclear cells (PBMCs). Expression of the 2 forms of BDNF receptors (active TrkB-FL and inactiveTrkB-T1) in PBMCs of FEP patients changed over time, TrkB-FL expression increasing by 1 year after diagnosis, while TrkB-T1 expression decreased. The TrkB-FL/TrkB-T1 ratio (hereafter FL/T1 ratio) increased during follow-up in the nonaffective psychosis group only, suggesting different underlying pathophysiological mechanisms in subgroups of FEP patients. Further, the expression of the main NGF receptor, TrkA, generally increased in patients at follow-up. After adjusting for potential confounders, baseline levels of inducible isoforms of nitric oxide synthase, cyclooxygenase, and nuclear transcription factor were significantly associated with the FL/T1 ratio, suggesting that more inflammation is associated with higher values of this ratio. Interestingly, the FL/T1 ratio might have a role as a predictor of functioning, a regression model of functioning at 1 year suggesting that the effect of the FL/T1 ratio at baseline on functioning at 1 year depended on whether patients were treated with antipsychotics. These findings may have translational relevance; specifically, it might be useful to assess the expression of TrkB receptor isoforms before initiating antipsychotic treatment in FEP

    Ion-exchanged geopolymer for photocatalytic degradation of a volatile organic compound

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    In thepresentworkitisshownhowgeopolymerscanbeusedtocontrolindoorandoutdoorair pollution byphotolysisof2-ButanoneasaVolatileOrganicCompound(VOC).Anionexchange procedurewasfollowedtoincorporateTiO2 into ageopolymer(IEG),anddifferent2-Butanone concentrations wereusedinabatchreactorunderdryandhumidconditions.Variationon 2-Butanone concentrationwasfollowedbygaschromatography.ALangmuir Hinshelwood modelwas used todeterminethedisappearancerateofreactantattheinitialstageofthereaction.Gasca-Tirado, J.; Manzano-Ramirez, A.; Vazquez-Landaverde, PA.; Herrera-Diaz, EI.; Rodriguez-Ugarte, ME.; Rubio-Avalos, JC.; Amigó Borrás, V.... (2014). Ion-exchanged geopolymer for photocatalytic degradation of a volatile organic compound. Materials Letters. 134:222-224. doi:10.1016/j.matlet.2014.07.090S22222413

    Hypofractionated radiation therapy and temozolomide in patients with glioblastoma and poor prognostic factors. A prospective, single-institution experience

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    Background: Hypofractionated radiation therapy is a feasible and safe treatment option in elderly and frail patients with glioblastoma. The aim of this study was to evaluate the effectiveness of hypofractionated radiation therapy with concurrent temozolomide in terms of feasibility and disease control in primary glioblastoma patients with poor prognostic factors other than advanced age, such as post-surgical neurological complications, high tumor burden, unresectable or multifocal lesions, and potential low treatment compliance due to social factors or rapidly progressive disease. Material and methods: GTV included the surgical cavity plus disease visible in T1WI-MRI, FLAIR-MRI and in the MET-uptake. The CTV was defined as the GTV plus 1.5-2 cm margin; the PTV was the CTV+0.3 cm margin. Forty, fourty-five, and fifty grays in 15 fractions were prescribed to 95% of PTV, CTV, and GTV, respectively. Treatment was delivered using IMRT or the VMAT technique. Simultaneously, 75 mg/m2/day of temozolomide were administered. Results: Between January 2010 and November 2017, we treated a total of 17 patients. The median age at diagnosis was 68-years; median KPS was 50-70%. MGMT-methylation status was negative in 5 patients, and 8 patients were IDH-wildtype. Eight of 18 patients were younger than 65-years. Median tumor volume was 26.95cc; median PTV volume was 322cc. Four lesions were unresectable; 6 patients underwent complete surgical resection. Median residual volume was 1.14cc. Progression-free survival was 60% at 6 months, 33% at 1-year and 13% at 2-years (median OS = 7 months). No acute grade 3-5 toxicities were documented. Symptomatic grade 3 radiation necrosis was observed in one patient. Conclusions: Patients with poor clinical factors other than advanced age can be selected for hypofractionated radiotherapy. The OS and PFS rates obtained in our series are similar to those in patients treated with standard fractionation, assuring good treatment adherence, low rates of toxicity and probable improved cost-effectiveness

    Flares, wind and nebulae: the 2015 December mini-outburst of V404 Cygni

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    After more than 26 years in quiescence, the black hole transient V404 Cyg went into a luminous outburst in June 2015, and additional activity was detected in late December of the same year. Here, we present an optical spectroscopic follow-up of the December mini-outburst, together with X-ray, optical and radio monitoring that spanned more than a month. Strong flares with gradually increasing intensity are detected in the three spectral ranges during the ∼ 10 days following the Swift trigger. Our optical spectra reveal the presence of a fast outflowing wind, as implied by the detection of a P-Cyg profile (He i–5876 ˚A) with a terminal velocity of ∼ 2500 kms−1 . Nebularlike spectra – with an H α equivalent width of ∼ 500 ˚A – are also observed. All these features are similar to those seen during the main June 2015 outburst. Thus, the fast optical wind simultaneous with the radio jet is most likely present in every V404 Cyg outburst. Finally, we report on the detection of a strong radio flare in late January 2016, when X-ray and optical monitoring had stopped due to Sun constraints
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