Search

• CoPc-Mn(OAc) 2 -HBr catalytic system for selective oxidation shows high quinclorac selectivity and yield. • CoPc leads to more active species of Co3+, and thus facilitating the catalytic performance. • Experiments and theoretical calculations have proven the generation of 3,7-dichloro quinoline-CO radical species. • A Co2+/Co3+ mediated free radical mechanism is proposed. Nowadays, the use of quinoline derived synthons as precursors of quinclorac products is an important research topic in green chemistry. O 2 is a cheap, stable, and eco-friendly oxidant, holding promise for organic oxidation reactions. Herein, we have pioneered the discovery of CoPc-Mn(OAc) 2 -HBr (CoPc-Mn-Br) catalyst system for the selective oxidation of 3,7-dichloro-8-dichloro methyl quinoline (3,7-D-8-DMQ) into quinclorac with high 3,7-D-8-DMQ conversion at 59.3 %. The CoPc-Mn-Br exhibits excellent selectivity of quinclorac (up to 60.3 %), affording high quinclorac yield of 35.7 %, which is 3.1-fold higher than the yield of Co(OAc) 2 -Mn(OAc) 2 -HBr (Co-Mn-Br). Electron paramagnetic resonance (EPR) investigations and density functional theory (DFT) calculations indicate that CoPc promotes the adsorption and activation of O 2 in this oxidation process, which generates more Co3+, leading to producing the reactive intermediate species 3,7-dichloro-8-carbonyl quinoline free radicals via the radical process. The insight achieved from this fundamental study may be further applied to other organic syntheses via selective oxidation. [ABSTRACT FROM AUTHOR]

Physiologic hypertrophy of the athlete heart, compared to the heart of nonathletic controls, is characterized by an increase in the left ventricular (LV) chamber dimension, mass, and wall thickness. Comparisons of the diastolic function (DF) between athletes and controls have employed conventional echocardiographic transmitral flow (Doppler E-wave)-derived indexes such as the peak flow velocity and deceleration time (which are load-dependent) and obscure the mechanistic determinants (e.g., stiffness, relaxation, load) of E-wave. With a focus on stiffness and relaxation chamber properties, conventional kinematic model-derived and load-independent indexes of the DF were compared between athletes and controls in this study. Echocardiographic and magnetic resonance imaging (MRI) data from 22 master athletes (whose sport was canoeing) and 21 sedentary controls were analyzed (1290 Doppler E-waves; 702 from athletes and 588 from the controls; on average, there were 30 pieces of data per subject). The LV mass and chamber size were determined from the MRI data. Quantitative DF assessment utilized an established kinematic model of filling that used the digitized Doppler E-wave contour as the input and characterized the DF on the basis of the chamber stiffness (k), relaxation/visco- elasticity (c), load (x„). We observed significant chamber stiffness (k), load (x„), and E-wave duration differences between the two groups. Concordant with the findings of previous studies, we also noted significant group differences in LV mass and dimension. These results indicated that physiological LV remodeling of the athlete heart at rest generates numerically quantifiable alterations in specific chamber properties. Assessment of the DF by using these methods during exercise will further elucidate the dynamic interplay between relaxation and stiffness as DF determinants. Copyright © 2013, The Society of Chinese Scholars on Exercise Physiology and Fitness. Published by Elsevier (Singapore) Pte Ltd. All rights reserved. [ABSTRACT FROM AUTHOR]

• The paper describes the first challenge on head and neck tumor segmentation in PET/CT. • Training (n = 201 , 4 centers) and test sets (n = 53 , 1 unseen center) amount to 254 cases. • All ground truth segmentations underwent cleaning to ensure quality and homogeneity. • The winning team obtained a DSC of 0.759, showing a larg improvement over the baseline. • Additional post-challenge analyses (e.g. false positives analysis, ranking stability). [Display omitted] This paper relates the post-analysis of the first edition of the HEad and neCK TumOR (HECKTOR) challenge. This challenge was held as a satellite event of the 23rd International Conference on Medical Image Computing and Computer-Assisted Intervention (MICCAI) 2020, and was the first of its kind focusing on lesion segmentation in combined FDG-PET and CT image modalities. The challenge's task is the automatic segmentation of the Gross Tumor Volume (GTV) of Head and Neck (H&N) oropharyngeal primary tumors in FDG-PET/CT images. To this end, the participants were given a training set of 201 cases from four different centers and their methods were tested on a held-out set of 53 cases from a fifth center. The methods were ranked according to the Dice Score Coefficient (DSC) averaged across all test cases. An additional inter-observer agreement study was organized to assess the difficulty of the task from a human perspective. 64 teams registered to the challenge, among which 10 provided a paper detailing their approach. The best method obtained an average DSC of 0.7591, showing a large improvement over our proposed baseline method and the inter-observer agreement, associated with DSCs of 0.6610 and 0.61, respectively. The automatic methods proved to successfully leverage the wealth of metabolic and structural properties of combined PET and CT modalities, significantly outperforming human inter-observer agreement level, semi-automatic thresholding based on PET images as well as other single modality-based methods. This promising performance is one step forward towards large-scale radiomics studies in H&N cancer, obviating the need for error-prone and time-consuming manual delineation of GTVs. [ABSTRACT FROM AUTHOR]