385 research outputs found

    Photochemical Energy Conversion with Artificial Molecular Machines

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    The exploitation of sunlight as a clean, renewable, and distributed energy source is key to facing the energetic demand of modern society in a sustainable and affordable fashion. In the past few decades, chemists have learned to make molecular machines, that is, synthetic chemical systems in which energy inputs cause controlled movements of molecular components that could be used to perform a task. A variety of artificial molecular machines operated by light have been constructed by implementing photochemical processes within appropriately designed (supra)molecular assemblies. These studies could open up new routes for the realization of nanostructured devices and materials capable to harness, convert, and store light energy

    Cardiocirculatory intraoperative assessment during single-shot caudal anaesthesia in children: comparison between levobupivacaine and ropivacaine

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    BACKGROUND: Caudal block with levobupivacaine or ropivacaine is the most commonly used regional anaesthesia in children. METHODS: The aim of study was to compare the cardiocirculatory profile induced in two matched groups of young patients, submitted to caudal anaesthesia with levobupivacaine or ropivacaine for an elective subumbilical surgery. Sixty children were enrolled: thirty received levopubivacaine 0.25% and thirty ropivacaine 0.2%. Intraoperative heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP) were monitored at following times: Ta0 (after anaesthesia induction), Tal (after caudal anaesthesia), Ta2 (five minutes later), Ta3 (ten minutes later), Ts1 (at surgical incision), Ts2, Ts3, Ts4, Ts5 (every 10 minutes during surgery), Taw (at the awakening). RESULTS: In both groups the cardiocirculatory trend remained within normal ranges at all times considered, demonstrating the safety of the method with both drugs. Both groups showed a similar trend at the different monitoring times: low decrease in HR, SBP and DBP after caudal block, slight increase in parameters after skin incision, slight decrease during surgery, increase at awakening. Regarding SBP and DBP, the levobupivacaine group children generally showed higher levels compared to the ropivacaine group, especially for DBP. CONCLUSIONS: Paediatric caudal anaesthesia is an effective method with an very infrequent complication rate. Possible hypotheses for differing haemodynamic behaviour could include a stronger vasoconstriction reflex of innervated areas during caudal anaesthesia with levobupivacaine and a lower levobupivacaine induced block of the sympathetic fibers, related to different pharmacokinetic profile of low concentrations of the local anaesthetics used in paediatric epidural space

    Aquatic Therapy after Incomplete Spinal Cord Injury: Gait Initiation Analysis Using Inertial Sensors

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    : Populations with potential damage to somatosensory, vestibular, and visual systems or poor motor control are often studied during gait initiation. Aquatic activity has shown to benefit the functional capacity of incomplete spinal cord injury (iSCI) patients. The present study aimed to evaluate gait initiation in iSCI patients using an easy-to-use protocol employing four wearable inertial sensors. Temporal and acceleration-based anticipatory postural adjustment measures were computed and compared between dry-land and water immersion conditions in 10 iSCI patients. In the aquatic condition, an increased first step duration (median value of 1.44 s vs. 0.70 s in dry-land conditions) and decreased root mean squared accelerations for the upper trunk (0.39 m/s2 vs. 0.72 m/s2 in dry-land conditions) and lower trunk (0.41 m/s2 vs. 0.85 m/s2 in dry-land conditions) were found in the medio-lateral and antero-posterior direction, respectively. The estimation of these parameters, routinely during a therapy session, can provide important information regarding different control strategies adopted in different environments

    Giant Shape-Persistent Tetrahedral Porphyrin System: Light-Induced Charge Separation

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    Tetraphenylmethane appended with four pyridylpyridinium units works as a scaffold to self-assemble four ruthenium porphyrins in a tetrahedral shape-persistent giant architecture. The resulting supramolecular structure has been characterised in the solid state by X-ray single crystal analysis and in solution by various techniques. Multinuclear NMR spectroscopy confirms the 1 : 4 stoichiometry with the formation of a highly symmetric structure. The self-assembly process can be monitored by changes of the redox potentials, as well as by modifications in the visible absorption spectrum of the ruthenium porphyrin and by a complete quenching of both the bright fluorescence of the tetracationic scaffold and the weak phosphorescence of the ruthenium porphyrin. An ultrafast photoinduced electron transfer is responsible for this quenching process. The lifetime of the resulting charge separated state (800 ps) is about four times longer in the giant supramolecular structure compared to the model 1 : 1 complex formed by the ruthenium porphyrin and a single pyridylpyridinium unit. Electron delocalization over the tetrameric pyridinium structure is likely to be responsible for this effect

    Changes in clinical characteristics and outcomes of patients admitted to inpatient cardiac rehabilitation

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    Aims: Cardiac rehabilitation (CR) have proven to be effective and beneficial in middle-aged and older patients. However, solid data in large cohorts of elderly individuals are yet to be explored. This retrospective study investigated the general characteristics, outcomes, and the level of re-sponse of patients referred to CR over 13 consecutive years. Methods: We reviewed the medical records of patients admitted to Villa Pineta Rehabilitation Hospital for exercise-based CR from 2006 to 2018. Patients’ baseline characteristics and changes following CR in upper limb weight-lifting test (ULW), 30-second sit-to-stand test (30STS), and the 6-minute walking test (6MWT) with associated Borg-related dyspnea (D) and fatigue (F) were collected. We also calculated the number of individuals reaching the minimal clinically relevant change (MCRC) following CR for each outcome. Results: 1551 patients (70.2 ± 9.7 years, 66% men) with complete data set were in-cluded in the analysis. Coronary artery bypass graft and cardiac valve replacement surgery were the most frequent surgical procedures leading to CR referral (41.1% and 35.8%, respectively). The patients’ age (p = 0.03), number of total comorbidities (p < 0.0001), and post-surgical complica-tions (p = 0.02) significantly increased over time. In contrast, the average absolute changes in ULW, 30STS and 6MWT with associated D and F, and the proportion of patients reaching the re-spective MCRC, remained constant over the same period. Conclusion: Patients admitted to exer-cise-based CR were older and had more comorbidities and complications over time. Outcomes, however, were not influenced in terms of absolute change nor clinically meaningful response

    Chemically Induced Mismatch of Rings and Stations in [3]Rotaxanes

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    The mechanical interlocking of molecular components can lead to the appearance of novel and unconventional properties and processes, with potential relevance for applications in nanoscience, sensing, catalysis, and materials science. We describe a [3]rotaxane in which the number of recognition sites available on the axle component can be changed by acid-base inputs, encompassing cases in which this number is larger, equal to, or smaller than the number of interlocked macrocycles. These species exhibit very different properties and give rise to a unique network of acid-base reactions that leads to a fine pKa tuning of chemically equivalent acidic sites. The rotaxane where only one station is available for two rings exhibits a rich coconformational dynamics, unveiled by an integrated experimental and computational approach. In this compound, the two crown ethers compete for the sole recognition site, but can also come together to share it, driven by the need to minimize free energy without evident inter-ring interactions
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