Assessing the Impact of Differential Measurement Error on Estimates of Fine Particle Mortality
摘要:
In air pollution epidemiology, error in measurements of correlated pollutants has been advanced as a reason to distrust regressions that find statistically significant weak associations. Much of the related debate in the literature and elswhere has been qualitative. To promote quantitative evaluation of such errors, this paper develops an air pollution time-series model based on correlations among unit-normal variables. Assuming there are no other sources of bias present, the model shows the expected amount of relative bias in the regression coefficients df a bivariate regression of coarse and fine particulate matter measurements on daily mortality. The model only requires information on instrumental error and spatial variability, along with the observed regression coefficients and information on the true fine-course correlation. Analytical results show that if one pollutant is truly more harmful than the other, then it must be measured more precisely than the other in order not to bias the ratio of the fine and course regression coefficients. Utilizing published data, a case study of the Harvard Six-Cities study illustrates use of the model and emphasizes the need for data on spatial variability across the study area. Current epidemiology time-series regressions can use this model to address the general concern of correlated pollutants with differing measurement errors.
Efficient reduction of sulfoxides with NaHSO 3 catalyzed by I 2
摘要:
An efficient method for the deoxygenation of sulfoxides into their corresponding sulfides at room temperature using NaHSO3 in the presence of catalytic I-2 has been reported. (C) 2015 Elsevier Ltd. All rights reserved.
A mild and efficient copper-catalyzed coupling of aryl iodides and thiols using an oxime–phosphine oxide ligand
作者:Di Zhu、Lei Xu、Fan Wu、Boshun Wan
DOI:10.1016/j.tetlet.2006.05.178
日期:2006.8
A mild and efficient copper-catalyzed system for the coupling of aryliodides and thiols was developed using a readily prepared and highly stable oxime–phosphine oxide ligand. Good to excellent yields were obtained.
C-S cross-coupling of aryl halides with alkyl thiols catalyzed by in-situ generated nickel(II) N-heterocyclic carbene complexes
作者:Fang-Jie Guo、Jing Sun、Zhao-Qing Xu、Fritz E. Kühn、Shu-Liang Zang、Ming-Dong Zhou
DOI:10.1016/j.catcom.2017.02.007
日期:2017.6
C-S cross-coupling of aryl halides with alkyl thiols catalyzed by in-situ generated Ni (II) N-heterocyclic carbene (NHC) complexes is investigated. Good to excellent yields can be obtained for a variety of aryl halides when using 5 mol% of the Ni (II)-NHC catalyst and 1.5 eq. of KOtBu. Both the electronic and steric effects of the NHC ligands on the catalytic performance of Ni (II)-NHC, as well as the
Preparation of Functionalized Diaryl- and Diheteroaryllanthanum Reagents by Fast Halogen-Lanthanum Exchange
作者:Andreas D. Benischke、Lucile Anthore-Dalion、Guillaume Berionni、Paul Knochel
DOI:10.1002/anie.201709553
日期:2017.12.18
Aryl and heteroaryl halides (X=Br, I) undergo a fast and convenient halogen–lanthanum exchange with nBu2LaMe, which leads to functionalized diaryl‐ and diheteroaryllanthanum derivatives. Subsequent trapping reactions with selected electrophiles, such as ketones, aldehydes, or amides, proceeded smoothly at −50 °C in THF, affording polyfunctionalized alcohols and carbonyl derivatives. Kinetic competition
Electrochemical Thiolation and Borylation of Arylazo Sulfones with Thiols and B
<sub>2</sub>
pin
<sub>2</sub>
作者:Rongkang Wang、Fangming Chen、Lvqi Jiang、Wenbin Yi
DOI:10.1002/adsc.202001518
日期:2021.3.29
arylazo sulfones were used as radical precursors for carbon‐heteroatom bond formation under electrochemical conditions. Moreover, the scalability of this approach was evaluated by performing the electrochemical thiolation and borylation of arylazo sulfones with thiols and B2pin2 on a gram scale. This protocol not only avoided the use of stoichiometric oxidants, metal catalysts, activating agents and
Efficient and Highly Selective Oxidation of Sulfides to Sulfoxides in the Presence of an Ionic Liquid Containing Hypervalent Iodine
作者:Weixing Qian、Lin Pei
DOI:10.1055/s-2006-933109
日期:——
A mild, efficient, highlyselective, and environmentally friendly oxidation of sulfides to sulfoxides with a recyclable ion-supportedhypervalentiodinereagent has been developed. This reaction is tolerant of hydroxyl, nitrile, methoxy, carbon-carbon double bonds, and ester functionalities. Aliphatic and aromatic sulfides are selectively oxidized to the corresponding sulfoxides at room temperature