Evidence of AlII Radical Addition to Benzene

Electrophilic AlIII species have long dominated the aluminum reactivity towards arenes. Recently, nucleophilic low-valent AlI aluminyl anions have showcased oxidative additions towards arenes C C and/or C H bonds. Herein, we communicate compelling evidence of an AlII radical addition reaction to the benzene ring. The electron reduction of a ligand stabilized precursor with KC8 in benzene furnishes a double addition to the benzene ring instead of a C H bond activation, producing the corresponding cyclohexa-1,3 (orl,4)-dienes as Birch-type reduction product. X-ray crystallographic analysis, EPR spectroscopy, and DFT results suggest this reactivity proceeds through a stable AlII radical intermediate, whose stability is a consequence of a rigid scaffold in combination with strong steric protection

Revisiting the origin of the bending in group 2 metallocenes AeCp2 (Ae = Be–Ba)

Metallocenes are well-established compounds in organometallic chemistry, and can exhibit either a coplanar structure or a bent structure according to the nature of the metal center (E) and the cyclopentadienyl ligands (Cp). Herein, we re-examine the chemical bonding to underline the origins of the geometry and stability observed experimentally. To this end, we have analysed a series of group 2 metallocenes [Ae(C5R5)2] (Ae = Be–Ba and R = H, Me, F, Cl, Br, and I) with a combination of computational methods, namely energy decomposition analysis (EDA), polarizability model (PM), and dispersion interaction densities (DIDs). Although the metal–ligand bonding nature is mainly an electrostatic interaction (65–78%), the covalent character is not negligible (33–22%). Notably, the heavier the metal center, the stronger the d-orbital interaction with a 50% contribution to the total covalent interaction. The dispersion interaction between the Cp ligands counts only for 1% of the interaction. Despite that orbital contributions become stronger for heavier metals, they never represent the energy main term. Instead, given the electrostatic nature of the metallocene bonds, we propose a model based on polarizability, which faithfully predicts the bending angle. Although dispersion interactions have a fair contribution to strengthen the bending angle, the polarizability plays a major role

An Innovative Methodology to Optimize Aerospace Eco-efficiency Assembly Processes

Sustainability and eco-efficiency have been researched in multiple scientific papers since the last years. However the literature is not so abundant when applying those concepts to industrial assembly processes. This paper presents an innovate methodology to optimize aerospace assembly processes. Authors propose the introduction of a new element, the eco-efficiency, along with the traditional criteria, cost and time, currently used for optimization. Using a large Aero-Structure as an industrial case of study, the methodology analyzes the eco-efficiency of an assembly process in connection with a Life Cycle Assessment (LCA) to compute the environmental impact. Results are shown in a dashboard along with the relevant Key Process Indicator (KPI) to help the engineers to select the best assembly processEuropean Union (UE). H2020 DILECO 785367European Union H2020-EU.3.4.5.4-IT

Patterns of knee osteoarthritis management in general practice:a retrospective cohort study using electronic health records

Objective: This study determined patterns of knee osteoarthritis (OA) management by general practitioners (GPs) using routine healthcare data from Dutch general practices from 2011 to 2019. Design: A retrospective cohort study was conducted using the Integrated Primary Care Information database between 2011 and 2019. Electronic health records (EHRs) of n = 750 randomly selected knee OA patients (with either codified or narrative diagnosis) were reviewed against eligibility criteria and n = 503 patients were included. Recorded information was extracted on GPs’ management from six months before to three years after diagnosis and patterns of management were analysed.Results: An X-ray referral was the most widely recorded management modality (63.2%). The next most widely recorded management modalities were a referral to secondary care (56.1%) and medication prescription or advice (48.3%). Records of recommendation of/referral to other primary care practitioners (e.g. physiotherapists) were found in only one third of the patients. Advice to lose weight was least common (1.2%). Records of medication prescriptions or recommendation of/referral to other primary care practitioners were found more frequently in patients with an X-ray referral compared to patients without, while records of secondary care referrals were found less frequently. Records of an X-ray referral were often found in narratively diagnosed knee OA patients before GPs recorded a code for knee OA in their EHR. Conclusion: These findings emphasize the importance of better implementing non-surgical management of knee OA in general practice and on initiatives for reducing the overuse of X-rays for diagnosing knee OA in general practice.</p

Early-stage [123I]beta-CIT SPECT and long-term clinical follow-up in patients with an initial diagnosis of Parkinson's disease

beta-CIT binding in both caudate nuclei was lower than in the group of patients with IPD. In addition, putamen to caudate binding ratios were higher in the group of APS patients. In spite of these differences, individual binding values showed considerable overlap between the groups. CONCLUSION: [(123)I]beta-CIT SPECT scanning in early-stage, untreated parkinsonian patients revealed a relative sparing of the caudate nucleus in patients with IPD as compared to patients later (re)diagnosed with APS. Nevertheless, the pattern of striatal involvement appears to have little predictive value for a later re-diagnosis of APS in individual case

Optimal spare parts management for vessel maintenance scheduling

Condition-based monitoring is used as part of predictive maintenance to collect real-time information on the healthy status of a vessel engine, which allows for a more accurate estimation of the remaining life of an engine or its parts, as well as providing a warning for a potential failure of an engine part. An engine failure results in delays and down-times in the voyage of a vessel, which translates into additional cost and penalties. This paper studies a spare part management problem for maintenance scheduling of a vessel operating on a given route that is defined by a sequence of port visits. When a warning on part failure is received, the problem decides when and to which port each part should be ordered, where the latter is also the location at which the maintenance operation would be performed. The paper describes a mathematical programming model of the problem, as well as a shortest path dynamic programming formulation for a single part which solves the problem in polynomial time complexity. Simulation results are presented in which the models are tested under different scenarios