Asymmetric Vinylogous Michael/Oxa-Michael Tandem Reaction between β,γ-Unsaturated Amides and Isatin-Derived β,γ-Unsaturated α-Ketoesters.

An organocatalytic asymmetric vinylogous Michael/oxa-Michael tandem reaction between β,γ-unsaturated pyrazoleamides and isatin-derived β,γ-unsaturated ketoesters has been developed with excellent regio-, diastereo-, and enantioselectivities. The methodology provides an effective approach to construct enantiomerically pure 3,4'-pyranyl spirooxindole derivatives containing three contiguous chiral centers. Moreover, the transformations of the chiral products, including the removal and reduction of the pyrazole group, have been investigated.

Selective Reduction of NO into N Catalyzed by the RhMO Clusters (M = Ta, V, and Al): Importance of the Triatomic Lewis Acid-Base-Acid M-Rh-M Site.

Catalytic NO reduction by CO into N and CO is imperative owing to the increasingly rigorous emission regulation. Identifying the nature of active sites that govern the reactivity and selectivity of NO reduction is pivotal to tailor catalysts, while it is extremely challenging because of the complexity of real-life systems. Guided by our newly discovered triatomic Lewis acid-base-acid (LABA, Ce-Rh-Ce) site that accounts for the selective reduction of NO into N catalyzed by the RhCeO cluster in gas-phase experiments, the reactivity of the RhMO (M = Ta, V, and Al) clusters in catalytic NO reduction by CO was explored.

Self-assembled FeO-COOH @ hydrogen-bonded organic framework composites for magnetic solid-phase extraction of tetracycline in food samples coupled with HPLC determination.

Magnetic solid-phase extraction (MSPE) technology for tetracycline (TCC) was developed by employing the novel and pre-designed FeO-COOH@hydrogen-bonded organic frameworks (HOFs) adsorbents in complex food samples. The HOF shell was grown onto the FeO-COOH core by in-situ self-assembled method. The excellent MSPE performances with less solvent, less adsorbent and time consumption were derived from the hydrogen bonding, π-π and hydrophobic interactions between HOF shell and TCC.

Effect of acacetin on inhibition of apoptosis in -infected gastric epithelial cell line.

Background: () infection can cause extensive apoptosis of gastric epithelial cells, serving as a critical catalyst in the progression from chronic gastritis, gastrointestinal metaplasia, and atypical gastric hyperplasia to gastric carcinoma. Prompt eradication of is paramount for ameliorating the pathophysiological conditions associated with chronic inflammation of the gastric mucosa and the primary prevention of gastric cancer. Acacetin, which has multifaceted pharmacological activities such as anti-cancer, anti-inflammatory, and antioxidative properties, has been extensively investigated across various domains.

Facile preparation of covalent-organic framework composites for magnetic solid-phase extraction of naphthaleneacetic acid in food prior to HPLC-UV analysis.

Novel magnetic covalent organic frameworks (COFs) were prepared by one-pot synthetic strategy and employed as an efficient adsorbent for magnetic solid-phase extraction (MSPE) of naphthaleneacetic acid (NAA) in food samples. Depending on the predesigned the hydrogen bonding, π-π and hydrophobic interactions of magnetic COFs, the efficient and selective extraction process for NAA was achieved within 15 min. The magnetic COFs adsorbent combined with HPLC-UV was devoted to develop a novel quantitative method for NAA in complex food.

Toward Designing Reactive Metal Clusters for Dinitrogen Activation: A Guideline Based on N Initial Adsorption.

Gas-phase metal clusters are ideal models to explore transition-metal-mediated N activation mechanism. However, the effective design and search of reactive clusters in N activation are currently hindered by the lack of clear guidelines. Inspired by the Sabatier principle, we discovered in this work that N initial adsorption energy (Δ) is an important parameter to control the N activation reactivity of metal clusters in the gas phase.

Reverse water-gas shift catalyzed by RhVO ( = 3-7) cluster anions under variable temperatures.

A fundamental understanding of the exact structural characteristics and reaction mechanisms of interface active sites is vital to engineering an energetic metal-support boundary in heterogeneous catalysis. Herein, benefiting from a newly developed high-temperature ion trap reactor, the reverse water-gas shift (RWGS) (CO + H → CO + HO) catalyzed by a series of compositionally and structurally well-defined RhVO ( = 3-7) clusters were identified under variable temperatures (298-773 K). It is discovered that the RhVO clusters can function more effectively to drive RWGS at relatively low temperatures.

Machine Learning for Experimental Reactivity of a Set of Metal Clusters toward C-H Activation.

Understanding the mechanisms of C-H activation of alkanes is a very important research topic. The reactions of metal clusters with alkanes have been extensively studied to reveal the electronic features governing C-H activation, while the experimental cluster reactivity was qualitatively interpreted case by case in the literature. Herein, we prepared and mass-selected over 100 rhodium-based clusters (RhVO and RhCoO) to react with light alkanes, enabling the determination of reaction rate constants spanning six orders of magnitude.

Spectroscopic Characterization of Thermal Methane Activation by Lewis-Acid-Base Pair in a Gas-Phase Metal Nitride Anion TaN.

Activation and transformation of methane is one of the "holy grails" in catalysis. Understanding the nature of active sites and mechanistic details via spectroscopic characterization of the reactive sites and key intermediates is of great challenge but crucial for the development of novel strategies for methane transformation. Herein, by employing photoelectron velocity-map imaging (PEVMI) spectroscopy in conjunction with quantum chemistry calculations, the Lewis acid-base pair (LABP) of [Ta-N] unit in TaN acting as an active center to accomplish the heterolytic cleavage of C-H bond in CH has been confirmed by direct characterization of the reactant ion TaN and the CH-adduct intermediate TaNCH .

Selective Reduction of NO into N Catalyzed by Rh-Doped Cluster Anions RhCeO.

Catalytic conversion of toxic nitrogen oxide (NO) and carbon monoxide (CO) into nitrogen (N) and carbon dioxide (CO) is imperative under the weight of the increasingly stringent emission regulations, while a fundamental understanding of the nature of the active site to selectively drive N generation is elusive. Herein, in combination with state-of-the-art mass-spectrometric experiments and quantum-chemical calculations, we demonstrated that the rhodium-cerium oxide clusters RhCeO can catalytically drive NO reduction by CO and give rise to N and CO. This finding represents a sharp improvement in cluster science where NO is commonly produced in the rarely established examples of catalytic NO reduction mediated with gas-phase clusters.

Using Normalized Carcinoembryonic Antigen and Carbohydrate Antigen 19 to Predict and Monitor the Efficacy of Neoadjuvant Chemotherapy in Locally Advanced Gastric Cancer.

Unlabelled: Carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) are established prognostic biomarkers for patients with gastric cancer. However, their potential as predictive markers for neoadjuvant chemotherapy (NACT) efficacy has not been fully elucidated.

Methods: We conducted a retrospective analysis to determine values of CEA and CA19-9 prior to NACT (pre-NACT) and after NACT (post-NACT) in 399 patients with locally advanced gastric cancer (LAGC) who received intended NACT and surgery.

Magnetic covalent organic frameworks for extraction and determination of endocrine-disrupting chemicals in beverage and water samples.

Background: Phenolic endocrine-disrupting chemicals (EDCs) are widespread and easily ingested through the food chain. They pose a serious threat to human health. Magnetic solid-phase extraction (MSPE) is an effective sample pre-treatment technology to determine traces of phenolic EDCs.

Activation of Dinitrogen Promoted by Adsorption of CH on FeVC Cluster Anions.

The introduction of organic ligands is one of the effective strategies to improve the stability and reactivity of metal clusters. Herein, the enhanced reactivity of benzene-ligated cluster anions FeVC(CH) with respect to naked FeVC is identified. Structural characterization suggests that CH is molecularly bound to the dual metal site in FeVC(CH).

Superior Reactivity of Molybdenum-Sulfur Cluster Anions MoS and MoS toward Dinitrogen.

Inspired by the fact that Mo is a key element in biological nitrogenase, a series of gas-phase MoS cluster anions are prepared and their reactivity toward N is investigated by the combination of mass spectrometry, photoelectron imaging spectroscopy, and density functional theory calculations. The MoS and MoS cluster anions show remarkable reactivity compared with the anionic species reported previously. The spectroscopic results in conjunction with theoretical analysis reveal that a facile cleavage of N≡N bonds takes place on MoS and MoS.

Associations of subcutaneous fat area and Systemic Immune-inflammation Index with survival in patients with advanced gastric cancer receiving dual PD-1 and HER2 blockade.

Background: Systemic Immune-inflammation Index (SII) and body composition parameters are easily assessed, and can predict overall survival (OS) in various cancers, allowing early intervention. This study aimed to assess the correlation between CT-derived body composition parameters and SII and OS in patients with advanced gastric cancer receiving dual programmed death-1 (PD-1) and human epidermal growth factor receptor 2 (HER2) blockade.

Materials And Methods: This retrospective study enrolled patients with advanced gastric cancer treated with dual PD-1 and HER2 blockade from March 2019 to June 2022.

The significance of time interval between perioperative SOX/XELOX chemotherapy and clinical decision model in gastric cancer.

Introduction: To investigate the influences of time interval between multimodality therapies on survival for locally advanced gastric cancer (LAGC) patients, 627 patients were included in a retrospective study, and 350 who received neoadjuvant chemotherapy (NACT) based on SOX (S-1 plus Oxaliplatin)/XELOX (Capecitabine plus Oxaliplatin) treatment, radical surgery, and adjuvant chemotherapy (AC) from 2005.01 to 2018.06 were eligible for analyses.

Dinitrogen Activation in the Gas Phase: Spectroscopic Characterization of C-N Coupling in the V C +N Reaction.

We report on cluster-mediated C-N bond formation in the gas phase using N as a nitrogen source. The V C +N reaction is studied by a combination of ion-trap mass spectrometry with infrared photodissociation (IRPD) spectroscopy and complemented by electronic structure calculations. The proposed reaction mechanism is spectroscopically validated by identifying the structures of the reactant and product ions.

A liquid biopsy signature of circulating exosome-derived mRNAs, miRNAs and lncRNAs predict therapeutic efficacy to neoadjuvant chemotherapy in patients with advanced gastric cancer.

At present, there is no validated marker to identify the subpopulation of patients with advanced gastric cancer (AGC) who might benefit from neoadjuvant chemotherapy (NACT). In view of this clinical challenge, the identification of non-invasive biomarkers for efficacy prediction of NACT in patients with AGC is imperative. Herein, we aimed to develop a non-invasive, liquid-biopsy-based assay by using an exosome-derived RNAs model based on multi-omics characteristics of RNAs.

A comparative study on the reactivity of ditantalum deuteride cluster anions TaD and TaD toward N.

The activation and transformation of molecular nitrogen (N) by metal hydride species has attracted widespread attention due to its critical role in nitrogen fixation. Herein, the reactions between tantalum deuteride cluster anions TaD and N were investigated experimentally and theoretically. An unprecedented reaction channel of the liberation of a single D atom was observed and much superior reactivity was identified for TaD.

Nomogram for predicting the prognosis of tumor patients with sepsis after gastrointestinal surgery.

Background: There were few studies on the prognosis of tumor patients with sepsis after gastrointestinal surgery and there was no relevant nomogram for predicting the prognosis of these patients.

Aim: To establish a nomogram for predicting the prognosis of tumor patients with sepsis after gastrointestinal surgery in the intensive care unit (ICU).

Methods: A total of 303 septic patients after gastrointestinal tumor surgery admitted to the ICU at Peking University Cancer Hospital from January 1, 2013 to December 31, 2020 were analysed retrospectively.

Mutual functionalization of dinitrogen and methane mediated by heteronuclear metal cluster anions CoTaC.

The direct coupling of dinitrogen (N) and methane (CH) to construct the N-C bond is a fascinating but challenging approach for the energy-saving synthesis of N-containing organic compounds. Herein we identified a likely reaction pathway for N-C coupling from N and CH mediated by heteronuclear metal cluster anions CoTaC , which starts with the dissociative adsorption of N on CoTaC to generate a Ta -N (terminal-nitrogen) Lewis acid-base pair (LABP), followed by the further activation of CH by CoTaCN to construct the N-C bond. The N[triple bond, length as m-dash]N cleavage by CoTaC affording two N atoms with strong charge buffering ability plays a key part, which facilitates the HC-H cleavage the LABP mechanism and the N-C formation a CH migration mechanism.

Reverse water-gas shift reaction catalyzed by diatomic rhodium anions.

The reverse water-gas shift (RWGS, CO + H → CO + HO, Δ = +0.44 eV) reaction mediated by the diatomic anion Rh was successfully constructed. The generation of a gas-phase HO molecule and ion product [Rh(CO)] was identified unambiguously at room temperature and the only elementary step that requires extra energy to complete the catalysis is the desorption of CO from [Rh(CO)].

Predictive scoring systems for molecular responses in persons with chronic phase chronic myeloid leukemia receiving initial imatinib therapy.

It is vital for physicians and persons with chronic myeloid leukemia (CML) to accurately predict the likelihood of achieving a major molecular response (MMR) and a deep molecular response (DMR; at least MR) at the start of imatinib-therapy, which could help in decision making of treatment goals and strategies. To answer this question, we interrogated data from 1369 consecutive subjects with chronic phase CML receiving initial imatinib-therapy to identify predictive co-variates. Subjects were randomly-assigned to training (n = 913) and validation (n = 456) datasets.