2,019 research outputs found

    Reluctant Cross-Metathesis Reactions: The Highly Beneficial Effect of Microwave Irradiation

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    carbene complexes ; catalysis ; cross coupling ; metathesis ; olefinationInternational audienceThe beneficial effect of microwave irradiation versus classical thermal conditions is demonstrated through a series of comparative cross-metathesis reactions

    Fabrication of Capacitive Acoustic Resonators Combining 3D Printing and 2D Inkjet Printing Techniques

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    International audienceA capacitive acoustic resonator developed by combining three-dimensional (3D) printing and two-dimensional (2D) printed electronics technique is described. During this work, a patterned bottom structure with rigid backplate and cavity is fabricated directly by a 3D printing method, and then a direct write inkjet printing technique has been employed to print a silver conductive layer. A novel approach has been used to fabricate a diaphragm for the acoustic sensor as well, where the conductive layer is inkjet-printed on a pre-stressed thin organic film. After assembly, the resulting structure contains an electrically conductive diaphragm positioned at a distance from a fixed bottom electrode separated by a spacer. Measurements confirm that the transducer acts as capacitor. The deflection of the diaphragm in response to the incident acoustic single was observed by a laser Doppler vibrometer and the corresponding change of capacitance has been calculated, which is then compared with the numerical result. Observation confirms that the device performs as a resonator and provides adequate sensitivity and selectivity at its resonance frequency

    Synthesis of functionalized tryptamines by Brønsted acid catalysed cascade reactions

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    An original synthetic protocol has been developed for the preparation of highly functionalized tryptamines from 2-hydroxycyclobutanone and secondary arylamines via a solvent-free Brønsted acid catalysed two-step reaction sequence

    Palliative care in Dutch hospitals: A rapid increase in the number of expert teams, a limited number of referrals

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    Background: Palliative care expert teams in hospitals have positive effects on the quality of life and satisfaction with care of patients with advanced disease. Involvement of these teams in medical care is also associated with substantial cost savings. In the Netherlands, professional standards state that each hospital should have a palliative care team by 2017. We studied the number of hospitals that have a palliative care team and the characteristics of these teams. Methods: In April 2015, questionnaires were mailed to key palliative care professionals in all general, teaching and academic hospitals in the Netherlands. Out of 92 hospitals, 74 responded (80 %). Results: Seventy-seven percent of all participating hospitals had a palliative care team. Other services, such as outpatient clinics (22 %), palliative care inpatient units (7 %), and palliative day care facilities (4 %) were relatively scarce. The mean number of disciplines that were represented in the teams was 6,5. The most common disciplines were nurses (72 %) and nurse practitioners (54 %), physicians specialized in internal medicine (90 %) or anaesthesiology (75 %), and spiritual caregivers (65 %). In most cases, the physicians did not have labeled hours available for their work as palliative care consultant, whereas nurses and nurse practitioners did. Most teams (77 %) were only available during office hours. Twenty-six percent of the teams could not only be consulted by healthcare professionals but also by patients or relatives. The annual number of consultations for inpatients per year ranged from 2 to 680 (median: 77). On average, teams were consulted for 0.6 % of all patients admitted to the hospitals. Conclusion: The number of Dutch hospitals with a palliative care team is rapidly increasing. There are substantial differences between teams regarding the disciplines represented in the teams, the procedures and the number of consultations. The development of quality standards and adequate staffing of the teams could improve the quality and effectiveness of the teams

    Characterization of organic ultra-thin film adhesion on flexible substrate using scratch test technique

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    International audienceThe mechanical properties of interfaces and more precisely the adhesion are of great importance for the understanding of the reliability of thin film devices. Organic thin film transistors (OTFT) on flexible substrate are a new class of electronic components. Since these devices are flexible and intended for different fields of application like sensors and displays, they will undergo a lot of mechanical and thermal stress during their useful life. Moreover, interfaces play an important role in the electrical stability of these transistors. In this context, the adhesion of two organic submicron thin films, semi conducting and dielectric respectively, deposited on polymeric substrate were investigated by scratch test method. This study demonstrates the feasibility and selectivity of the scratch test as a tool for assessing the adhesion and the damage behaviour of ultra-thin organic film on flexible plastic substrate. The semi-crystalline substrate presents a brittle cracking damage from a given strain, whereas when covered by the semi-conducting thin film, the sample exhibits a more ductile behaviour. Moreover, this technique has proven to be sensitive enough to highlight the effects of a plasma treatment prior to deposition

    Feature selection and classification of imbalanced datasets. Application to PET images of children with Autistic Spectrum Disorders

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    Learning with discriminative methods is generally based on minimizing themisclassification of training samples, which may be unsuitable for imbalanceddatasets where the recognition might be biased in favor of the most numerousclass. This problem can be addressed with a generative approach, which typicallyrequires more parameters to be determined leading to reduced performances inhigh dimension. In such situations, dimension reduction becomes a crucial issue.We propose a feature selection / classification algorithm based on generativemethods in order to predict the clinical status of a highly imbalanced datasetmade of PET scans of forty-five low-functioning children with autism spectrumdisorders (ASD) and thirteen non-ASD low-functioning children. ASDs aretypically characterized by impaired social interaction, narrow interests, andrepetitive behaviours, with a high variability in expression and severity. Thenumerous findings revealed by brain imaging studies suggest that ASD isassociated with a complex and distributed pattern of abnormalities that makesthe identification of a shared and common neuroimaging profile a difficult task.In this context, our goal is to identify the rest functional brain imagingabnormalities pattern associated with ASD and to validate its efficiency inindividual classification. The proposed feature selection algorithm detected acharacteristic pattern in the ASD group that included a hypoperfusion in theright Superior Temporal Sulcus (STS) and a hyperperfusion in the contralateralpostcentral area. Our algorithm allowed for a significantly accurate (88\%),sensitive (91\%) and specific (77\%) prediction of clinical category. For thisimbalanced dataset, with only 13 control scans, the proposed generativealgorithm outperformed other state-of-the-art discriminant methods. The highpredictive power of the characteristic pattern, which has been automaticallyidentified on whole brains without any priors, confirms previous findingsconcerning the role of STS in ASD. This work offers exciting possibilities forearly autism detection and/or the evaluation of treatment response in individualpatients
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