Reported here are the isolation, structural characterization, and decomposition kinetics of the four-coordinate pentachloroethyl nickel complex, NiCl(CCl2CCl3)(CNAr(Mes2))2 (Ar(Mes2) = 2,6-(2,4,6-Me3C6H2)2C6H3). This complex is a unique example of a kinetically persistent β-chloroalkyl in a system relevant to coordination-insertion polymerization of polar olefins. Kinetic analysis of NiCl(CCl2CCl3)(CNAr(Mes2))2 decomposition indicates that β-chloride (β-Cl) elimination proceeds by a unimolecular mechanism that does not require initial dissociation of a CNAr(Mes2) ligand. The results suggest that a direct β-Cl elimination pathway is available to four-coordinate, Group 10 metal vinyl chloride polymerization systems.
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http://dx.doi.org/10.1021/ja508956q | DOI Listing |
Chirality
February 2025
Daicel Chiral Technologies, West Chester, Pennsylvania, USA.
The influence of additives and modifiers on the chiral HPLC separation of the nicotine enantiomers using UV/Vis detection is discussed. Selected alcohols as modifiers and selected amines as additives were found to have a significant effect on the resolution and retention times of nicotine enantiomers even to the point of eliminating component elution. Systematic variations in the concentration of ethanol, methanol, and isopropanol, as modifiers, along with variations in the concentration of diethylamine, triethylamine, tributylamine, ethylenediamine, isopropylamine, as additives, revealed that the average resolution (R) of the nicotine enantiomers ranged from 2.
View Article and Find Full Text PDFCell Prolif
January 2025
Department of Nursing, Sichuan Clinical Research Center for Cancer, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, University of Electronic Science and Technology of China, Chengdu, China.
Vasculogenic mimicry (VM) represents a novel form of angiogenesis discovered in numerous malignant tumours in recent years. Unlike traditional angiogenesis, VM facilitates tumour blood supply independently of endothelial cells by enabling tumour cells to form functional vascular networks. This phenomenon, where tumour cells replace endothelial cells to form tubular structures, plays a pivotal role in tumour growth and metastasis.
View Article and Find Full Text PDFMed Phys
January 2025
Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Hokkaido, Japan.
Background: The use of iodinated contrast-enhancing agents in computed tomography (CT) improves the visualization of relevant structures for radiotherapy treatment planning (RTP). However, it can lead to dose calculation errors by incorrectly converting a CT number to electron density.
Purpose: This study aimed to propose an algorithm for deriving virtual non-contrast (VNC) electron density from dual-energy CT (DECT) data.
BMC Res Notes
January 2025
Department of Surgery, Department of Clinical Sciences, Division of Surgery, Skåne University Hospital, Lund University, Lund, Sweden.
Objectives: Positive resection margins after breast-conserving surgery (BCS) most often demands a repeat surgery. To preoperatively identify patients at risk of positive margins, a multivariable model has been developed that predicts positive margins after BCS with a high accuracy. This study aimed to externally validate this prediction model to explore its generalizability and assess if additional preoperatively available variables can further improve its predictive accuracy.
View Article and Find Full Text PDFBMC Med
January 2025
Department of Pharmaceutical Biosciences, Uppsala University, Box 593, Husargatan 3, Uppsala, 751 24, Sweden.
Background: Lifestyle choices, such as dietary patterns and sleep duration, significantly impact the health of the digestive system and may influence the risk of mortality from digestive system cancer.
Methods: This study aimed to examine the associations between sleep duration, dietary habits, and mortality from digestive system cancers. The analysis included 406,584 participants from the UK Biobank cohort (54.
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