Fuenteschristie4484

We have quantum chemically studied the reactivity, site-, and regioselectivity of the 1,3-dipolar cycloaddition reaction between methyl azide and various allenes, including the archetypal allene propadiene, heteroallenes, and cyclic allenes, using density functional theory (DFT). The  1,3-dipolar  cycloaddition reactivity of linear (hetero)allenes decreases as the number of heteroatoms in the allene increases and the formation of the 1,5-adduct is, in all cases, favored over the 1,4-adduct, both effects find their origin from the strength of the primary orbital interactions . The cycloaddition reactivity of cyclic allenes was also investigated, and the increased predistortion of allenes,  that results upon cyclization, leads to systematically lower activation barriers not due to the expected variations in the strain energy, but instead from the differences in the interaction energy . The geometrical predistortion of cyclic allenes enhances the reactivity compared to linear allenes  through a unique mechanism that involves a smaller HOMO-LUMO gap, which manifests into more stabilizing orbital interactions . © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.BACKGROUND The association between palatin-like phospholipase domain-containing 3 (PNPLA3) I148M (rs738409) polymorphism and mortality is not well understood. We investigated the impact of PNPLA3 I148M (rs738409) polymorphism on overall and cardiovascular mortality based on the presence of NAFLD. METHODS The Third National Health and Nutrition Examination Survey (NHANES) from 1991 to 1994 and NHANES III-linked mortality data through 31 December 2015 were utilized in this study. RESULTS Of 4,814 participants, 50.7% were homozygous for the C-allele and 12.6% were homozygous for the G-allele. During a follow-up of 20 years, there were a total of 1,255 deaths, 422 attributed to cardiovascular disease. There was a significant association with overall mortality among those with the PNPLA3 I148M (rs738409) GG genotype (hazard ratio [HR] 1.34; 95% confidence interval [CI] 1.02-1.77) or G-allele (HR 1.22 95% CI 1.09-1.36) in the general population NAFLD with homozygous PNPLA3 I148M (rs738409) GG genotype had higher overall mortality after adjusting for multiple metabolic risk factors (hazard ratio [HR] 1.45; 95% confidence interval [CI] 1.01-2.08). The PNPLA3 I148M (rs738409) G-allele had a tendency of increased cardiovascular mortality in the total population. This association was not noted in those with NAFLD. CONCLUSIONS The homozygous PNPLA3 I148M (rs738409) GG genotype showed an increase in overall mortality in the general population and NAFLD independent of multiple metabolic risk factors. This article is protected by copyright. All rights reserved.OBJECTIVE There is much controversy about the neurobiological mechanisms underlying the effects of sleep-disordered breathing on the brain. The aim of this study was to investigate the association between markers of sleep-related hypoxemia and brain anatomy. METHODS We used data from a large-scale cohort from the general population (n = 775, 50.6% males, age range = 45-86 years, mean age = 60.3 ± 9.9) that underwent full polysomnography and brain MRI to correlate respiratory variables with regional brain volume estimates. RESULTS After adjusting for age, gender, and cardiovascular risk factors, only mean oxygen saturation during sleep was associated with bilateral volume of hippocampus (right p = 0.001; left p  less then  0.001), thalamus (right p  less then  0.001; left p  less then  0.001), putamen (right p = 0.001; left p = 0.001) and angular gyrus (right p = 0.011; left p = 0.001). We observed the same relationship in left hemispheric amygdala (p = 0.010), caudate (p = 0.008), inferior frontal gyrus (p = 0.004) and supramarginal gyrus (p = 0.003). The other respiratory variables - lowest oxygen saturation, % of sleep time with oxygen saturation  less then  90%, apnea-hypopnea index and oxygen desaturation index - did not show any significant association with brain volumes. INTERPRETATION Lower mean oxygen saturation during sleep was associated with atrophy of cortical and subcortical brain areas known for high sensitivity to oxygen supply. Their vulnerability to hypoxemia may contribute to behavioral phenotype and cognitive decline in patients with sleep-disordered breathing. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.While the natural transition orbital (NTO) method has allowed electronic excitations from time-dependent Hartree-Fock and density functional theory to be viewed in a traditional orbital picture, the extension to multicomponent molecular orbitals such as those used in relativistic two-component methods or generalized Hartree-Fock (GHF) or generalized Kohn-Sham (GKS) is less straightforward due to mixing of spin-components and the inherent inclusion of spin-flip transitions in time-dependent GHF/GKS. An extension of single-component NTOs to the two-component framework is presented, in addition to a brief discussion of the practical aspects of visualizing two-component complex orbitals. Unlike the single-component analog, the method explicitly describes the spin and frequently obtains solutions with several significant orbital pairs. The method is presented using calculations on a mercury atom and a CrO2 Cl2 complex. U18666A in vitro © 2020 Wiley Periodicals, Inc.OBJECTIVES To describe a novel surgical technique in which neuronavigation is used to guide a tissue resection device during excision of forebrain masses in locations difficult to visualize optically. STUDY DESIGN Short case series. ANIMALS Six dogs and one cat with forebrain masses (five neoplastic, two nonneoplastic) undergoing excision with a novel tissue resection device and veterinary neuronavigation system. METHODS The animals and resection instrument were coregistered to the neuronavigation system. Surgery was guided by real-time onscreen visualization of the resection instrument position relative to the preoperative MR images. Surgical outcome was evaluated by calculating residual tumor volume according to postoperative MRI. RESULTS The technique was technically simple and led to the collection of diagnostic tissue samples in all cases. Postoperative MRI was available in six cases, two with gross-total resection, three with near-total resection, and one with subtotal resection. CONCLUSION Neuronavigation-guided resection of intra-axial and extra-axial brain masses with the resection device resulted in gross-total or near-total resection in five of six animals with tumors otherwise difficult to visualize.