Infrared Metrics for Fixation-Free Liver Tumor Detection

Infrared (IR) spectroscopic imaging of human liver tissue slices has been used to identify and characterize liver tumors. Liver tissue, containing a liver metastasis of breast origin (mucinous carcinoma), was surgically removed from a consenting patient and frozen without formalin fixation or dehydration procedures, so that lipids and water remained in the tissues. A set of IR metrics (ratios of various IR peaks) was determined for tumors in fixation-free liver tissues. K-means cluster analysis was used to tell tumor from nontumor. In this case, there was a large reduction in lipid content upon going from nontumor to tumor tissue, and a well-resolved IR spectrum of nontumor liver lipid was obtained and analyzed. These IR metrics may someday guide work on IR spectroscopic diagnostics on patients in the operating room. This work also suggests utility for these methods beyond the identification of liver tumors, perhaps in the study of liver lipids

Theoretical study on the BF3-catalyzed meinwald rearrangement reaction

The mechanisms of the BF3-catalyzed Meinwald rearrangement reactions of five epoxides in dichloromethane solution have been studied at the M062X/6-311++G(2df,2pd) level. Accordingly, the Lewis acid-epoxide complex can react through several alternative pathways, though three phases (ring opening, C-C bond rotation, and hydrogen or alkyl group migration) are required in any path. In some cases, a concerted pathway (involving all three successive phases) is found. Otherwise, the reaction takes place through a reaction mechanism involving a zwitterion or a BF3 addition compound (formed by fluoride transfer from the BF3 moiety to the incipient carbocationic center generated by C-O bond rupture) or both as reaction intermediate(s). The BF 2-bound fluorohydrin yields the reaction product through a concerted process involving fluoride transfer from the C-F bond to the OBF2 group and hydrogen or alkyl group migration, as first demonstrated in this work. Effects of a number of features (solvent effects, concurrent hydrogen/alkyl group migration, carbocation substitution, benzylic conjugation) are also discussed. © 2014 American Chemical Society.Financial support from the Ministerio de Ciencia e Innovación (MICINN/FEDER) of Spain (Project CTQ2011-28124) and the Gobierno de Aragón (Group E11) is gratefully acknowledged.Peer Reviewe

Measurement of the lifetimes of promptly produced Ωc0Ω^{0}_{c} and Ξc0Ξ^{0}_{c} baryons

A measurement of the lifetimes of the $\Omega^{0}_{c}$ and $\Xi^{0}_{c}$ baryons is reported using proton-proton collision data at a centre-of-mass energy of $13\text{ TeV}$, corresponding to an integrated luminosity of $5.4\text{ fb}^{-1}$ collected by the LHCb experiment. The $\Omega^{0}_{c}$ and $\Xi^{0}_{c}$ baryons are produced directly from proton interactions and reconstructed in the $pK^{-}K^{-}\pi^{+}$ final state. The $\Omega^{0}_{c}$ lifetime is measured to be $276.5\pm13.4\pm4.4\pm0.7\text{ fs}$, and the $\Xi^{0}_{c}$ lifetime is measured to be $148.0\pm2.3\pm2.2\pm0.2\text{ fs}$, where the first uncertainty is statistical, the second systematic, and the third due to the uncertainty on the $D^{0}$ lifetime. These results confirm previous LHCb measurements based on semileptonic beauty-hadron decays, which disagree with earlier results of a four times shorter $\Omega^{0}_{c}$ lifetime, and provide the single most precise measurement of the $\Omega^{0}_{c}$ lifetime

Measurement of the lifetimes of promptly produced Omega(0)(c) and Xi(9)(c) baryons

A measurement of the lifetimes of the Omega(0)(c) and Xi(0)(c) baryons is reported using proton-proton collision data at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb(-1) collected by the LHCb experiment. The Omega(0)(c) and Xi(0)(c) baryons are produced directly from proton interactions and reconstructed in the pK(-)K(-)pi(+) final state. The Omega(0)(c) lifetime is measured to be 276.5 +/- 13.4 +/- 4.4 +/- 0.7 fs, and the Xi(0)(c) lifetime is measured to be 148.0 +/- 2.3 +/- 2.2 +/- 0.2 fs, where the first uncertainty is statistical, the second systematic, and the third due to the uncertainty on the D-0 lifetime. These results confirm previous LHCb measurements based on semileptonic beauty-hadron decays, which disagree with earlier results of a four times shorter Omega(c)0 lifetime, and provide the single most precise measurement of the Omega(0 )(c)lifetime. (C) 2021 Science China Press. Published by Elsevier B.V. and Science China Press