332 research outputs found

    Electron density of a benzoylated tetrafructopyranose

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    The electron density distribution (EDD) of a tetrasaccharide composed of four benzoylated fructopyranosyl units was obtained by refinement with scattering factors from the invariom library. X-ray diffraction data was downloaded from the Cambridge Structural Database (CSD). Bond topological and atomic properties were obtained by application of Baderā€™s QTAIM formalism. From a large number of 105 Cā€“C bonds in the molecule average bond orders for 33 single and 72 aromatic bonds were calculated yielding values of 1.33 and 1.61. Molecular Hirshfeld and electrostatic potential (ESP) surfaces show that only weak non-covalent interactions exist. The phenyl rings of the benzoyl fragments in the outer regions of the molecule generate a positive ESP shell with repulsive properties between adjacent molecules. Weak surface interactions result in a rather unusual low density around 1.3 g cmāˆ’3, which is understandable when compared to other carbohydrates where strong Oā€“Hā‹ÆO hydrogen bonds allow a 20% more dense packing with densities >1.5 g cmāˆ’3 as determined by single crystal X-ray diffraction

    "This has to be the cats": personal data legibility in networked sensing systems

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    Notions like ā€˜Big Dataā€™ and the ā€˜Internet of Thingsā€™ turn upon anticipated harvesting of personal data through ubiquitous computing and networked sensing systems. It is largely presumed that understandings of peopleā€™s everyday interactions will be relatively easy to ā€˜read offā€™ of such data and that this, in turn, poses a privacy threat. An ethnographic study of how people account for sensed data to third parties uncovers serious challenges to such ideas. The study reveals that the legibility of sensor data turns upon various orders of situated reasoning involved in articulating the data and making it accountable. Articulation work is indispensable to personal data sharing and raises real requirements for networked sensing systems premised on the harvesting of personal data

    N-Methyl-N-styrylcinnamamide (lansamide) from Clausena lansium in Vietnam

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    The title compound, C18H17NO, was isolated from the seeds of Clausena lansium (wampee) (Rutaceae). The X-ray crystal structure analysis confirmed its chemical identity and revealed that it is solvent-free, in contrast to the previously reported monohydrate [Huang, Ou & Tang (2006 ā–¶). Acta Cryst. E62, o1987ā€“o1988]. The molĀ­ecular structures are practically identical but the molĀ­ecules pack differently. In contrast to the monohydrate in which the water molecule generates two hydrogen bonds, no such intermolecular contacts are present in the title compound. The dihedral angle between the cinnamamide and the styryl group is 53.1ā€…(1)Ā°

    Analysis of two [2]catenanes based on electron densities from invariom refinement and results from DFT calculations

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    The authors are grateful to the Deutsche Forschungsgemeinschaft (DFG) for financial support by project DI 921/6-1.Catenanes are of considerable interest as potential building blocks for molecular machines. The simplest [2]catenanes, Hopf links, consist of two macrocycles that are mechanically interlocked. This unusual architecture cannot be opened without breaking at least one covalent bond. Based on these structural characteristics, unusual properties on Hirshfeld or electrostatic potential surfaces could be expected. For a comparison of their structural and electronic properties, the electron densities (EDs) of two [2]catenanes, coded H22 and H4L7 in the original papers, were examined after application of the invariom formalism, relying on X-ray diffraction data collected earlier. The obtained electron density distributions were subjected to an analysis using the QTAIM formalism to yield bond and atomic properties. Moreover, molecular Hirshfeld surfaces and electrostatic potentials (ESP) were calculated. There are different types of intra- and intermolecular interactions in these two [2]catenanes. In addition to classical N-HĀ·Ā·Ā·N and C-HĀ·Ā·Ā·O hydrogen bonds, various types of Ļ€Ā·Ā·Ā·Ļ€ interactions in H22 and in H4L7 exist. Most of them are verified by local ED concentrations visible on the corresponding Hirshfeld surfaces, except for the parallel Ļ€Ā·Ā·Ā·Ļ€ interactions in H22, which are either too weak or too diffuse to generate an ED signal on the Hirshfeld surface between the contributing aromatic rings. The electrostatic potentials (ESPs) were calculated and displayed on molecular surfaces. The interaction in the cavity of one macrocycle with the penetrated fragment of the second one was examined and it was found that corresponding to the above-mentioned contacts attractive and repulsive interactions exist. Additionally the ED was examined using results of density functional calculations, including non-covalent interaction index (NCI) and electron localizability indicator (ELI-D) surface analysis, complementing experimental findings.Publisher PDFPeer reviewe

    Automated Annotation of Functional Imaging Experiments via Multi-Label Classification

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    Identifying the experimental methods in human neuroimaging papers is important for grouping meaningfully similar experiments for meta-analyses. Currently, this can only be done by human readers. We present the performance of common machine learning (text mining) methods applied to the problem of automatically classifying or labeling this literature. Labeling terms are from the Cognitive Paradigm Ontology (CogPO), the text corpora are abstracts of published functional neuroimaging papers, and the methods use the performance of a human expert as training data. We aim to replicate the expertā€™s annotation of multiple labels per abstract identifying the experimental stimuli, cognitive paradigms, response types, and other relevant dimensions of the experiments. We use several standard machine learning methods: naive Bayes (NB), k -nearest neighbor, and support vector machines (specifically SMO or sequential minimal optimization). Exact match performance ranged from only 15% in the worst cases to 78% in the best cases. NB methods combined with binary relevance transformations performed strongly and were robust to overfitting. This collection of results demonstrates what can be achieved with off-the-shelf software components and little to no pre-processing of raw text

    Adherence to oral anticoagulant therapy in secondary stroke prevention – impact of the novel oral anticoagulants

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    Background: Oral anticoagulant therapy (OAT) potently prevents strokes in patients with atrial fibrillation. Vitamin K antagonists (VKA) have been the standard of care for long-term OAT for decades, but non-VKA oral anticoagulants (NOAC) have recently been approved for this indication, and raised many questions, among them their influence on medication adherence. We assessed adherence to VKA and NOAC in secondary stroke prevention. Methods: All patients treated from October 2011 to September 2012 for ischemic stroke or transient ischemic attack with a subsequent indication for OAT, at three academic hospitals were entered into a prospective registry, and baseline data and antithrombotic treatment at discharge were recorded. At the 1-year follow-up, we assessed the adherence to different OAT strategies and patients' adherence to their respective OAT. We noted OAT changes, reasons to change treatment, and factors that influence persistence to the prescribed OAT. Results: In patients discharged on OAT, we achieved a fatality corrected response rate of 73.3% (n=209). A total of 92% of these patients received OAT at the 1-year follow-up. We observed good adherence to both VKA and NOAC (VKA, 80.9%; NOAC, 74.8%; P=0.243) with a statistically nonsignificant tendency toward a weaker adherence to dabigatran. Disability at 1-year follow-up was an independent predictor of lower adherence to any OAT after multivariate analysis, whereas the choice of OAT did not have a relevant influence. Conclusion: One-year adherence to OAT after stroke is strong (>90%) and patients who switch therapy most commonly switch toward another OAT. The 1-year adherence rates to VKA and NOAC in secondary stroke prevention do not differ significantly between both therapeutic strategies

    Independent Prognostic Significance of Monosomy 17 and Impact of Karyotype Complexity in Monosomal Karyotype/Complex Karyotype Acute Myeloid Leukemia: Results from Four ECOG-ACRIN Prospective Therapeutic Trials

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    The presence of a monosomal karyotype (MK+) and/or a complex karyotype (CK+) identifies subcategories of AML with poor prognosis. The prognostic significance of the most common monosomies (monosomy 5, monosomy 7, and monosomy 17) within MK+/CK+ AML is not well defined. We analyzed data from 1,592 AML patients age 17ā€“93 years enrolled on ECOG-ACRIN therapeutic trials. The majority of MK+ patients (182/195; 93%) were MK+/CK+ with 87% (158/182) having ā‰„5 clonal abnormalities (CKā‰„ 5). MK+ patients with karyotype complexity ā‰¤4 had a median overall survival (OS) of 0.4y compared to 1.0y for MK- with complexity ā‰¤4 (p < 0.001), whereas no OS difference was seen in MK+ vs. MK- patients with CKā‰„ 5 (p = 0.82). Monosomy 5 (93%; 50/54) typically occurred within a highly complex karyotype and had no impact on OS (0.4y; p = 0.95). Monosomy 7 demonstrated no impact on OS in patients with CKā‰„ 5 (p = 0.39) or CK ā‰¤ 4 (p = 0.44). Monosomy 17 appeared in 43% (68/158) of CKā‰„ 5 patients and demonstrated statistically significant worse OS (0.4y) compared to CKā‰„ 5 patients without monosomy 17 (0.5y; p = 0.012). Our data suggest that the prognostic impact of MK+ is limited to those with less complex karyotypes and that monosomy 17 may independently predict for worse survival in patients with AML

    EvoChromo: towards a synthesis of chromatin biology and evolution

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    Over the past few years, interest in chromatin and its evolution has grown. To further advance these interests, we organized a workshop with the support of The Company of Biologists to debate the current state of knowledge regarding the origin and evolution of chromatin. This workshop led to prospective views on the development of a new field of research that we term ā€˜EvoChromoā€™. In this short Spotlight article, we define the breadth and expected impact of this new area of scientific inquiry on our understanding of both chromatin and evolution

    GRAPPA-OMERACT consensus-based recommendations and research agenda for use of composite measures and treatment targets in PsA

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    BACKGROUND: Many composite disease activity measures and targets have been developed for psoriatic arthritis (PsA). This GRAPPA-OMERACT work stream aimed to further the development of consensus among physicians and patients.METHODS: Prior to the meeting, physicians and patients were surveyed on outcome measures. A consensus meeting (26 rheumatologists, dermatologists, and patient representatives) reviewed evidence on composite measures and potential treatment targets, plus survey results. After discussions, participants voted on proposals for use and consensus was established in a second survey.RESULTS: Survey results from 128 HCPS and 139 patients were analysed alongside a SLR summarising evidence. A weighted vote was cast for composite measures (for RCTs, most popular measures were PASDAS [40 votes] and GRACE [28 votes]; for clinical practice, most popular were 3-VAS [45 votes], DAPSA [26 votes]). After discussion there was no consensus on a composite measure. The group agreed that several composite measures could be used. Future studies should allow further validation and comparison. The group unanimously agreed that remission should be the ideal target with minimal/low disease activity a feasible alternative. The target should include assessment of musculoskeletal disease, skin and health related quality of life. The group recommended a target of treatment as VLDA, or MDA.CONCLUSIONS: Consensus was not reached on a continuous measure of disease activity. In the interim the group recommends several composites. Consensus was reached on a treatment target of VLDA/MDA. An extensive research agenda was composed and recommends that data on all PsA clinical domains be collected in ongoing studies. This article is protected by copyright. All rights reserved.</p

    PARP1 ADP-ribosylates lysine residues of the core histone tails

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    The chromatin-associated enzyme PARP1 has previously been suggested to ADP-ribosylate histones, but the specific ADP-ribose acceptor sites have remained enigmatic. Here, we show that PARP1 covalently ADP-ribosylates the amino-terminal histone tails of all core histones. Using biochemical tools and novel electron transfer dissociation mass spectrometric protocols, we identify for the first time K13 of H2A, K30 of H2B, K27 and K37 of H3, as well as K16 of H4 as ADP-ribose acceptor sites. Multiple explicit water molecular dynamics simulations of the H4 tail peptide into the catalytic cleft of PARP1 indicate that two stable intermolecular salt bridges hold the peptide in an orientation that allows K16 ADP-ribosylation. Consistent with a functional cross-talk between ADP-ribosylation and other histone tail modifications, acetylation of H4K16 inhibits ADP-ribosylation by PARP1. Taken together, our computational and experimental results provide strong evidence that PARP1 modifies important regulatory lysines of the core histone tails
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