New magnetically recoverable heterogeneous Pd-catalyst active in the alcoxycarbonylation of iodobenzene

Carbon-carbon bond formation is a long-standing challenge to organic chemists and several catalytic approaches have been developed during the past decades. Among these, the palladium-catalyzed carbonylation of aryl halides and their derivatives represents a powerful method for the synthesis of many aromatic compounds; especially, carboxylic acids and their derivatives. However, the difficult separation of the products from catalyst in the traditional homogeneous catalysis hinders sometimes its application in industrial process. This problem can be overcome by means of heterogeneous catalysis used nowadays in many industries to produce a variety of commercial products. Although in the heterogeneous catalysts the catalyst can be readily recovered usually by filtration or centrifugation catalyst recovery and reuse remain the two most important features for many green synthetic methods.Recently, new smart supports (magnetic nanoparticles, MNPs) have emerged and have great potential for catalyst recovery, because magnetic separation from the reaction mixture with an external permanent magnet is typically simpler and more effective than filtration or centrifugation as it prevents loss of the catalyst

Sensitivity and specificity of in vivo COVID-19 screening by detection dogs: Results of the C19-Screendog multicenter study

Trained dogs can recognize the volatile organic compounds contained in biological samples of patients with COVID-19 infection. We assessed the sensitivity and specificity of in vivo SARS-CoV-2 screening by trained dogs.We recruited five dog-handler dyads. In the operant conditioning phase, the dogs were taught to distinguish between positive and negative sweat samples collected from volunteers' underarms in polymeric tubes. The conditioning was validated by tests involving 16 positive and 48 negative samples held or worn in such a way that the samples were invisible to the dog and handler. In the screening phase the dogs were led by their handlers to a drive-through facility for in vivo screening of volunteers who had just received a nasopharyngeal swab from nursing staff. Each volunteer who had already swabbed was subsequently tested by two dogs, whose responses were recorded as positive, negative, or inconclusive. The dogs’ behavior was constantly monitored for attentiveness and wellbeing.All the dogs passed the conditioning phase, their responses showing a sensitivity of 83–100% and a specificity of 94–100%. The in vivo screening phase involved 1251 subjects, of whom 205 had a COVID-19 positive swab and two dogs per each subject to be screened. Screening sensitivity and specificity were respectively 91.6–97.6% and 96.3–100% when only one dog was involved, whereas combined screening by two dogs provided a higher sensitivity. Dog wellbeing was also analyzed: monitoring of stress and fatigue suggested that the screening activity did not adversely impact the dogs’ wellbeing. This work, by screening a large number of subjects, strengthen recent findings that trained dogs can discriminate between COVID-19 infected and healthy human subjects and introduce two novel research aspects: i) assessement of signs of fatigue and stress in dogs during training and testing, and ii) combining screening by two dogs to improve detection sensitivity and specificity.Using some precautions to reduce the risk of infection and spillover, in vivo COVID-19 screening by a dog-handler dyad can be suitable to quickly screen large numbers of people: it is rapid, non-invasive and economical, since it does not involve actual sampling, lab resources or waste management, and is suitable to screen large numbers of people