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Sonne Lu posted an update 6 months ago
A copper-based complex that contains a sulfonate N-heterocyclic carbene ligand was first reported 15 years ago. Since then, these organometallic entities have proven to be uniquely effective in catalyzing an assortment of enantioselective transformations, including allylic substitutions, conjugate additions, proto-boryl additions to alkenes, boryl and silyl substitutions, hydride-allyl additions to alkenyl boronates, and additions of boron-containing allyl moieties to N-H ketimines. In this review article, we detail the shortcomings in the state-of-the-art that fueled the development of this air stable ligand class, members of which can be prepared on multigram scale. For each reaction class, when relevant, the prior art at the time of the advance involving sulfonate NHC-Cu catalysts and/or subsequent key developments are briefly analyzed, and its relevance to efficient and enantioselective total or formal synthesis of biologically active molecules is underscored. Mechanistic analysis of the structural attributes of sulfonate NHC-Cu catalysts that are responsible for their ability to facilitate transformations with high efficiency as well as regio- and enantioselectivity are detailed. This review contains several formerly undisclosed methodological advances and mechanistic analyses, the latter of which constitute a revision of previously reported proposals. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.OBJECTIVE Many people who think about suicide do not engage in suicidal behavior. Identifying risk factors implicated in the process of behavioral enaction is crucial for suicide prevention, particularly in high-risk groups such as prisoners. METHOD Cross-sectional data were drawn from a nationally representative sample of 17,891 prisoners (79% men) in the United States. We compared prisoners who attempted suicide (attempters; n = 2,496) with those who thought about suicide but never made an attempt (ideators; n = 1,716) on a range of established risk factors. RESULTS More than half (59%) of participants who experienced suicidal ideation had also attempted suicide. Violent offending, trauma, brain injury, alcohol abuse, and certain mental disorders distinguished attempters from ideators. CONCLUSION Our results fit within recent ideation-to-action theories that emphasize the role of a capability for suicide in the transition from thoughts to acts of suicide. © 2020 The American Association of Suicidology.OBJECTIVE To test for an association between blood loss and time until pushing (TUP) after full cervical dilation in nulliparous women with epidural analgesia. METHODS A prospective cohort study was performed at the University Hospital of Zurich between October 2015 and November 2016. Included were 228 nulliparous women with singleton pregnancy, planned vaginal delivery after 36 completed weeks of gestation, epidural analgesia, and guided active pushing. click here TUP was defined as the interval between full cervical dilation and initiation of active pushing. The primary outcome measure was blood loss, assessed by the postpartum decrease in hemoglobin (ΔHb), estimated blood loss, and rate of ΔHb ≥30 g/L. Associations between TUP and primary and secondary maternal and neonatal delivery outcomes were assessed using Spearman correlation, Mann-Whitney U test, Kruskal-Wallis test, or Fisher exact test, as appropriate. RESULTS Longer TUP correlated significantly with increased ΔHb (ρ=0.142, P=0.033) and higher rates of ΔHb ≥30 g/l (P=0.002). Composite adverse maternal and neonatal outcomes were unaffected. CONCLUSION On the grounds of increased maternal blood loss, and in contrast to the current International Federation of Gynecology and Obstetrics (FIGO) guideline, delayed active pushing is not recommended in nulliparous women with epidural analgesia. This article is protected by copyright. All rights reserved.OBJECTIVES/HYPOTHESIS To review the demographics, treatment, and survival of pediatric melanoma of the head and neck and to determine if melanoma of the head and neck has worse survival than melanoma of other body sites. STUDY DESIGN Retrospective database review. METHODS Pediatric patients from 0 to 21 years in the Surveillance, Epidemiology, and End Results 18 registries database were included from 1975 to 2016 based on a diagnosis of melanoma of the skin using the primary site International Classification of Diseases for Oncology, Third Edition codes from C44.0-C44.9.skin of lip, C44.1-eyelid, C44.2-external ear, C44.3-skin other/unspecified parts of face, C44.4-skin of scalp and neck, C44.5-skin of trunk, C44.6-skin of upper limb and shoulder, C44.7-skin of lower limb and hip, C44.8-overlapping lesion of skin, and C44.9-skin, NOS (not otherwise specified). RESULTS A total of 4,561 pediatric melanomas of the skin were identified. There were 854 (18.7%) cases of melanoma of the head and neck (MHN) and 3,707 (81.3%) cases of melanoma of the body (MOB). The hazard ratio for MHN versus MOB was 1.6 (95% confidence interval 1.3-2.1) after accounting for sex, race, and age. Of MHN sites, the hazard ratio for melanoma of the scalp and neck was 2.2 (1.1-4.7). The 2- and 5-year Kaplan-Meier overall survival for MHN were 94.6% and 90.7%, respectively, compared with 96.6% and 94.7%, respectively, for MOB (P less then .01). CONCLUSIONS Survival outcomes of pediatric melanoma are notably related to anatomic site. Children with melanoma of the scalp and neck have the worst survival of all sites. Additionally, children who are older/white/male are at greater risk for worse survival outcomes. LEVEL OF EVIDENCE 3 Laryngoscope, 2020. © 2020 The American Laryngological, Rhinological and Otological Society, Inc.Marine heatwaves can lead to rapid changes in entire communities, including in the case of shallow coral reefs the potential overgrowth of algae. Here we tested experimentally the differential thermal tolerance between algae and coral species from the Red Sea through the measurement of thermal performance curves and the assessment of thermal limits. Differences across functional groups (algae vs corals) were apparent for two key thermal performance metrics. First, two reef-associated algae species (Halimeda tuna and Turbinaria ornata,) had higher lethal thermal limits than two coral species (Pocillopora verrucosa and Stylophora pistillata) conferring those species of algae with a clear advantage during heatwaves by surpassing the thermal threshold of coral survival. Second, the coral species had generally greater deactivation energies for net and gross primary production rates compared to the algae species, indicating greater thermal sensitivity in corals once the optimum temperature is exceeded. Our field surveys in the Red Sea reefs before and after the marine heatwave of 2015 show a change in benthic cover mainly in the southern reefs, where there was a decrease in coral cover and a concomitant increase in algae abundance, mainly turf algae.