A nickel‐catalyzed three‐component reaction for the synthesis of difluoroalkylated compounds through tandem difluoroalkylation‐arylation of enamides has been developed. The reaction tolerates a ...variety of arylboronic acids and widely available difluoroalkyl bromides, and even the relatively inert substrate chlorodifluoroacetate. The significant advantages of this protocol are the low‐cost nickel catalyst, synthetic convenience, excellent functional‐group compatibility and high reaction efficiency.
All about efficiency: The title reaction tolerates a variety of arylboronic acids and widely available difluoroalkyl bromides, and even the relatively inert substrate chlorodifluoroacetate. The protocol provides a highly efficient method for the catalytic synthesis of difluoroalkylated compounds.
An efficient palladium‐catalyzed Heck‐type reaction of fluoroalkyl halides, including perfluoroalkyl bromides, trifluoromethyl iodides, and difluoroalkyl bromides, has been developed. The reaction ...proceeds under mild reaction conditions with high efficiency and broad substrate scope, and provides a general and straightforward access to fluoroalkylated alkenes which are of interest in life and material sciences.
Simplicity is beauty: The title reaction features a broad substrate scope and excellent functional‐group compatibility. Mechanistic studies reveal that the free fluoroalkyl radicals initiated by Pd0Ln through a single‐electron transfer pathway is involved in the Heck‐type catalytic cycle.
An efficient and general method for the synthesis of difluoroalkylated phenanthridine derivatives through palladium-catalyzed reaction of difluoroalkyl bromides with isocyanides is described. The ...reaction can also be extended to perfluoroalkyl iodides. Mechanistic studies reveal that a difluoroalkyl radical via a single-electron-transfer pathway is involved in the reaction.
Reactive polymer blending is basically a flow/mixing‐driven process of interfacial generation, interfacial reaction for copolymer formation, and morphology development. This work shows two ...antagonistic effects of flow/mixing on this process: while flow/mixing promotes copolymer formation by creating interfaces and enhancing collisions between reactive groups at the interfaces, excessive flow/mixing may pull the in situ formed copolymer out of the interfaces to one of the two polymer components of the blend, especially when the copolymer becomes highly asymmetrical. As such, the copolymer may lose its compatibilization efficiency. The mixing‐driven copolymer pull‐out from the interfaces is a catastrophic process (less than a minute), despite the high viscosity of the polymer blend. It depends on the molecular architecture of the reactive compatibilizer, polymer blend composition, flow/mixing intensity, and annealing. These findings are obtained using the concept of reactive compatibilizer‐tracer and a model reactive polymer blend.
Two-dimensional materials provide extraordinary opportunities for exploring phenomena arising in atomically thin crystals. Beginning with the first isolation of graphene, mechanical exfoliation has ...been a key to provide high-quality two-dimensional materials, but despite improvements it is still limited in yield, lateral size and contamination. Here we introduce a contamination-free, one-step and universal Au-assisted mechanical exfoliation method and demonstrate its effectiveness by isolating 40 types of single-crystalline monolayers, including elemental two-dimensional crystals, metal-dichalcogenides, magnets and superconductors. Most of them are of millimeter-size and high-quality, as shown by transfer-free measurements of electron microscopy, photo spectroscopies and electrical transport. Large suspended two-dimensional crystals and heterojunctions were also prepared with high-yield. Enhanced adhesion between the crystals and the substrates enables such efficient exfoliation, for which we identify a gold-assisted exfoliation method that underpins a universal route for producing large-area monolayers and thus supports studies of fundamental properties and potential application of two-dimensional materials.
Objectives
This study was conducted in order to establish and validate a radiomics model for predicting lymph node (LN) metastasis of intrahepatic cholangiocarcinoma (IHC) and to determine its ...prognostic value.
Methods
For this retrospective study, a radiomics model was developed in a primary cohort of 103 IHC patients who underwent curative-intent resection and lymphadenectomy. Radiomics features were extracted from arterial phase computed tomography (CT) scans. A radiomics signature was built based on highly reproducible features using the least absolute shrinkage and selection operator (LASSO) method. Multivariate logistic regression analysis was adopted to establish a radiomics model incorporating radiomics signature and other independent predictors. Model performance was determined by its discrimination, calibration, and clinical usefulness. The model was internally validated in 52 consecutive patients.
Results
The radiomics signature comprised eight LN-status–related features and showed significant association with LN metastasis in both cohorts (
p
< 0.001). A radiomics nomogram that incorporates radiomics signature and CA 19-9 level showed good calibration and discrimination in the primary cohort (AUC 0.8462) and validation cohort (AUC 0.8921). Promisingly, the radiomics nomogram yielded an AUC of 0.9224 in the CT-reported LN-negative subgroup. Decision curve analysis confirmed the clinical utility of this nomogram. High risk for metastasis portended significantly lower overall and recurrence-free survival than low risk for metastasis (both
p
< 0.001). The radiomics nomogram was an independent preoperative predictor of overall and recurrence-free survival.
Conclusions
Our radiomics model provided a robust diagnostic tool for prediction of LN metastasis, especially in CT-reported LN-negative IHC patients, that may facilitate clinical decision-making.
Key Points
• The radiomics nomogram showed good performance for prediction of LN metastasis in IHC patients, particularly in the CT-reported LN-negative subgroup.
• Prognosis of high-risk patients remains dismal after curative-intent resection.
• The radiomics model may facilitate clinical decision-making and define patient subsets benefiting most from surgery.
Current guidelines recommend surgical resection as the first-line option for patients with solitary hepatocellular carcinoma (HCC); unfortunately, postoperative recurrence rate remains high and there ...is no reliable prediction tool. We explored the potential of radiomics coupled with machine-learning algorithms to improve the predictive accuracy for HCC recurrence.
A total of 470 patients who underwent contrast-enhanced CT and curative resection for solitary HCC were recruited from 3 independent institutions. In the training phase of 210 patients from Institution 1, a radiomics-derived signature was generated based on 3384 engineered features extracted from primary tumor and its periphery using aggregated machine-learning framework. We employed Cox modeling to build predictive models. The models were then validated using an internal dataset of 107 patients and an external dataset of 153 patients from Institution 2 and 3.
Using the machine-learning framework, we identified a three-feature signature that demonstrated favorable prediction of HCC recurrence across all datasets, with C-index of 0.633–0.699. Serum alpha-fetoprotein, albumin-bilirubin grade, liver cirrhosis, tumor margin, and radiomics signature were selected for preoperative model; postoperative model incorporated satellite nodules into above-mentioned predictors. The two models showed superior prognostic performance, with C-index of 0.733–0.801 and integrated Brier score of 0.147–0.165, compared with rival models without radiomics and widely used staging systems (all P < 0.05); they also gave three risk strata for recurrence with distinct recurrence patterns.
When integrated with clinical data sources, our three-feature radiomics signature promises to accurately predict individual recurrence risk that may facilitate personalized HCC management.
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•We identified a three-feature fusion signature using machine-learning framework.•The signature coupled with clinical sources accurately predicted HCC recurrence.•This signature may serve as an early detector of aggressive disease.•We highlight the complementary nature of radiomics and existing variables.
An ortho‐selective CF bond borylation between N‐heterocycle‐substituted polyfluoroarenes and Bpin‐Bpin with simple and commercially available Rh(cod)2BF4 as a catalyst is now reported. The reaction ...proceeds under mild reaction conditions with high efficiency and broad substrate scope, even toward monofluoroarene, thus providing a facile access to a wide range of borylated fluoroarenes that are useful for photoelectronic materials. Preliminary mechanistic studies reveal that a RhIII/V catalytic cycle via a key intermediate rhodium(III) hydride complex (H)RhIIILn(Bpin) may be involved in the reaction.
RhIII/V for borylation: The significant features of the title reaction are the simple catalytic system, the broad substrate scope, and the efficient synthesis of photoelectronic materials. A RhIII/V catalytic cycle is proposed for the reaction, which involves a rhodium(III) hydride complex as a key intermediate.
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