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1.
Nano Lett ; 24(25): 7672-7680, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38869481

RESUMO

Kagome materials have recently garnered substantial attention due to the intrinsic flat band feature and the stimulated magnetic and spin-related many-body physics. In contrast to their bulk counterparts, two-dimensional (2D) kagome materials feature more distinct kagome bands, beneficial for exploring novel quantum phenomena. Herein, we report the direct synthesis of an ultrathin kagome-structured Co-telluride (Co9Te16) via a molecular beam epitaxy (MBE) route and clarify its formation mechanism from the Co-intercalation in the 1T-CoTe2 layers. More significantly, we unveil the flat band states in the ultrathin Co9Te16 and identify the real-space localization of the flat band states by in situ scanning tunneling microscopy/spectroscopy (STM/STS) combined with first-principles calculations. A ferrimagnetic order is also predicted in kagome-Co9Te16. This work should provide a novel route for the direct synthesis of ultrathin kagome materials via a metal self-intercalation route, which should shed light on the exploration of the intriguing flat band physics in the related systems.

2.
Chem Commun (Camb) ; 60(49): 6276-6279, 2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38809134

RESUMO

A high concentration gel polymer electrolyte (GPE) was prepared by simply using LiFSI-LiNO3 dissolved in 1,3-dioxolane. The Li‖Li cell achieves stable battery cycling for over 3200 h. Furthermore, the Li‖Cu cell demonstrates a high CE of 99.2%. Even at a high current density of 8 mA cm-2, a high CE of 98.5% was still achieved. Notably, in a Li‖LiFePO4 cell, this electrolyte enables high capacity retention of 94.5% and an average CE of 99.8% over 500 cycles, showing promising prospects for high-performance lithium metal batteries.

3.
Angew Chem Int Ed Engl ; 63(26): e202404515, 2024 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-38637293

RESUMO

Reductive amination of carbonyl compounds and nitro compounds represents a straightforward way to attain imines or secondary amines, but it is difficult to control the product selectivity. Herein, we report the selective formation of C-N or C=N bond readily manipulated through a solvent-induced hydrogen bond bridge, facilitating the swift photocatalytic reductive coupling process. The reductive-coupling of nitro compounds with carbonyl compounds using formic acid and sodium formate as the hydrogen donors over CdS nanosheets selectively generates imines with C=N bonds in acetonitrile solvent; while taking methanol as solvent, the C=N bonds are readily hydrogenated to the C-N bonds via hydrogen-bonding activation. Experimental and theoretical study reveals that the building of the hydrogen-bond bridge between the hydroxyl groups in methanol and the N atoms of the C=N motifs in imines facilitates the transfer of hydrogen atoms from CdS surface to the N atoms in imines upon illumination, resulting in the rapid hydrogenation of the C=N bonds to give rise to the secondary amines with C-N bonds. Our method provides a simple way to control product selectivity by altering the solvents in photocatalytic organic transformations.

4.
J Colloid Interface Sci ; 664: 588-595, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38490034

RESUMO

Layered manganese-based cathode materials are considered as one of the promising cathodes benefit from inherent low manufacturing cost, non-toxic and high safety in aqueous zinc-ion batteries (AZIBs). However, the sluggish reaction kinetics within layered cathodes is inevitable due to the poor electrical/ionic conductivity. Herein, MnTiO3 is reported as a new cathode material for AZIBs and in-situ induced Mn-defect within MnTiO3 during the first charging is desirable to improve the reaction kinetics to a great extent. Additionally, DFT calculations further demonstrate that MnTiO3 with manganese defects exhibits a uniform charge distribution at the defect sites, enhancing the attraction towards H+ and Zn2+ ions. Furthermore, it performs good cycling stability which can obtain 115 mA h g-1 even at 400 mA g-1 after 450 cycles and the discharge capacity reaches up to 233.8 mAh/g at 100 mA g-1 when Mn-defect MnTiO3 was employed as the cathode. This research could provide a new method for the development and mechanism research of cathode materials for AZIBs.

5.
Nat Commun ; 15(1): 2722, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38548744

RESUMO

Enhancement of wakefulness is a prerequisite for adaptive behaviors to cope with acute stress, but hyperarousal is associated with impaired behavioral performance. Although the neural circuitries promoting wakefulness in acute stress conditions have been extensively identified, less is known about the circuit mechanisms constraining wakefulness to prevent hyperarousal. Here, we found that chemogenetic or optogenetic activation of GAD2-positive GABAergic neurons in the midbrain dorsal raphe nucleus (DRNGAD2) decreased wakefulness, while inhibition or ablation of these neurons produced an increase in wakefulness along with hyperactivity. Surprisingly, DRNGAD2 neurons were paradoxically wakefulness-active and were further activated by acute stress. Bidirectional manipulations revealed that DRNGAD2 neurons constrained the increase of wakefulness and arousal level in a mouse model of stress. Circuit-specific investigations demonstrated that DRNGAD2 neurons constrained wakefulness via inhibition of the wakefulness-promoting paraventricular thalamus. Therefore, the present study identified a wakefulness-constraining role DRNGAD2 neurons in acute stress conditions.


Assuntos
Núcleo Dorsal da Rafe , Vigília , Camundongos , Animais , Vigília/fisiologia , Núcleo Dorsal da Rafe/fisiologia , Nível de Alerta/fisiologia , Mesencéfalo , Neurônios GABAérgicos/fisiologia
6.
Angew Chem Int Ed Engl ; 63(9): e202317339, 2024 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-38085966

RESUMO

CeO2 nanorod based catalysts for the base-free synthesis of azoxy-aromatics via transfer hydrogenation of nitroarenes with ethanol as hydrogen donor have been synthesized and investigated. The oxygen vacancies (Ov ) and base sites are critical for their excellent catalytic properties. The Ov , i.e., undercoordinated Ce cations, serve as the sites to activate ethanol and nitroarenes by lowering the energy barrier to transfer hydrogen from α-Csp3 -H in ethanol to the nitro group coupling it to the redox reactions between Ce3+ and Ce4+ . At the same time, the base sites catalyze the condensation step to selectively produce azoxy-aromatics. The catalytic route opens a much improved way to use non-noble metal oxides without additives for the selective functional group reduction and coupling reactions.

7.
Adv Mater ; 36(14): e2311149, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38153318

RESUMO

Slow multi-proton coupled electron transfer kinetics and unexpected desorption of intermediates severely hinder the selectivity of CO2 methanation. In this work, a one-stone-two-bird strategy of pumping protons and improving adsorption configuration/capability enabled by electron localization is developed to be highly efficient for CH4 electrosynthesis over Cu single atoms anchored on bismuth vacancies of BiVO4 (Bi1-xVO4─Cu), with superior kinetic isotope effect and high CH4 Faraday efficiency (92%), far outperforming state-of-the-art electrocatalysts for CO2 methanation. Control experiments and theoretical calculations reveal that the bismuth vacancies (VBi) not only act as active sites for H2O dissociation but also induce electron transfer toward Cu single-atom sites. The VBi-induced electron localization pumps *H from VBi sites to Cu single atoms, significantly promoting the generation and stabilization of the pivotal intermediate (*CHO) for highly selective CH4 electrosynthesis. The metal vacancies as new initiators show enormous potential in the proton transfer-involved hydrogenative conversion processes.

8.
Molecules ; 28(22)2023 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-38005279

RESUMO

Salix babylonica L. is a species of willow tree that is widely cultivated worldwide as an ornamental plant, but its medicinal resources have not yet been reasonably developed or utilized. Herein, we extracted and purified the total flavonoids from willow buds (PTFW) for component analysis in order to evaluate their in vitro anti-tumor and hypoglycemic activities. Through Q-Orbitrap LC-MS/MS analysis, a total of 10 flavonoid compounds were identified (including flavones, flavan-3-ols, and flavonols). The inhibitory effects of PTFW on the proliferation of cervical cancer HeLa cells, colon cancer HT-29 cells, and breast cancer MCF7 cells were evaluated using an MTT assay. Moreover, the hypoglycemic activity of PTFW was determined by investigating the inhibitory effects of PTFW on α-amylase and α-glucosidase. The results indicated that PTFW significantly suppressed the proliferation of HeLa cells, HT-29 cells, and MCF7 cells, with IC50 values of 1.432, 0.3476, and 2.297 mg/mL, respectively. PTFW, at different concentrations, had certain inhibitory effects on α-amylase and α-glucosidase, with IC50 values of 2.94 mg/mL and 1.87 mg/mL, respectively. In conclusion, PTFW at different doses exhibits anti-proliferation effects on all three types of cancer cells, particularly on HT-29 cells, and also shows significant hypoglycemic effects. Willow buds have the potential to be used in functional food and pharmaceutical industries.


Assuntos
Flavonoides , Salix , Humanos , Flavonoides/farmacologia , Flavonoides/análise , Hipoglicemiantes/farmacologia , Hipoglicemiantes/análise , Extratos Vegetais/farmacologia , Extratos Vegetais/análise , Cromatografia Líquida , Células HeLa , alfa-Glucosidases , Espectrometria de Massas em Tandem , alfa-Amilases
9.
Inorg Chem ; 62(37): 15277-15292, 2023 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-37656824

RESUMO

The construction of strong metal-support interactions in oxide-supported noble metal nanocatalysts has been considered an emerging and efficient way in improving catalytic performance in biomass-upgrading reactions. Herein, a citric acid (CA)-assisted synthesized ZrO2 layer with improved oxygen vacancy (Ov) concentrations on a natural clay mineral of halloysite nanotubes (HNTs) was designed. Moreover, AuxPdy/ZrO2@HNTs-zCA catalysts were prepared by loading AuPd bimetal and employed for aerobic oxidation of the lignocellulosic biomass-derived 5-hydroxymethylfurfural (HMF) platform to the bioplastic monomer 2,5-furandicarboxylic acid (FDCA) with water as the solvent. The results of catalytic experiments revealed that the Au3Pd1/ZrO2@HNTs-1.0CA catalyst exhibited excellent catalytic activity at 0.5 MPa O2, with a satisfactory FDCA yield of 99.5% and outstanding FDCA formation rate of 1057.9 mmol·g-1·h-1. The improved Ov concentration in the ZrO2 support enhanced the adsorption and activation ability of the catalyst for O2, and a higher Lewis acid concentration provided a stronger adsorption ability of the catalyst for reaction substrates. Besides, the synergistic effect of AuPd bimetallic nanoparticles steered the tandem oxidation of aldehyde and alcohol groups in HMF and accelerated the rate-determining step. More importantly, the relationship between the Ov concentration and catalytic performance also demonstrated that the enhanced catalytic activity for HMF oxidation was mainly attributed to the active interface of AuPd-ZrOx. This work offers fresh insights into rationally designing oxygen vacancy-driven strong interactions between the oxide support and noble nanoparticles for the catalytic upgrade of biomass platform chemicals.

10.
Cell Discov ; 9(1): 95, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37714834

RESUMO

The extensively activated Notch signaling pathway in pancreatic cancer cells is important in carcinogenesis, chemoresistance, and recurrence. Targeting this pathway is a promising therapeutic strategy for pancreatic cancer; however, few successful approaches have been reported, and currently used molecular inhibitors of this pathway exhibit limited clinical benefits. In this study, we identified a previously uncharacterized microprotein, Notch1 degradation-associated regulatory polypeptide (N1DARP), encoded by LINC00261. N1DARP knockout accelerated tumor progression and enhanced stem cell properties in pancreatic cancer organoids and LSL-Kras, LSL-Trp53, and Pdx1-Cre (KPC) mice. Mechanistically, N1DARP suppressed canonical and non-canonical Notch1 pathways by competitively disrupting the interaction between N1ICD and ubiquitin-specific peptidase 10 (USP10), thereby promoting K11- and K48-linked polyubiquitination of N1ICD. To evaluate the therapeutic potential of N1DARP, we designed a cell-penetrating stapled peptide, SAH-mAH2-5, with a helical structure similar to that of N1DARP that confers remarkable physicochemical stability. SAH-mAH2-5 interacted with and promoted the proteasome-mediated degradation of N1ICD. SAH-mAH2-5 injection provided substantial therapeutic benefits with limited off-target and systemic adverse effects in Notch1-activated pancreatic cancer models. Taken together, these findings confirm that N1DARP acts as a tumor suppressor and chemosensitizer by regulating USP10-Notch1 oncogenic signaling, and suggest a promising therapeutic strategy targeting the N1DARP-N1ICD interaction in Notch1-activated pancreatic cancer.

11.
Chem Commun (Camb) ; 59(80): 11923-11931, 2023 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-37712348

RESUMO

The aerobic oxidative cleavage of C-C bonds is an attractive and sustainable route for constructing valuable molecules such as esters, nitriles, and amides. Traditionally homogeneous catalytic systems for C-C bond cleavage required harsh conditions, stoichiometric oxidants, and noble metal catalysts to overcome the thermodynamic and kinetic barriers of C-C bonds, imposing environmental concerns of the transformation. Therefore, developing efficient, low-cost, and environmentally benign methods for C-C bond cleavage is of great importance and a cutting-edge area in modern chemistry. This feature article summarizes the sustainable aerobic oxidative C-C bond cleavage method developed by our group in the past 5 years. Fundamental principles in catalyst design, substrate scope, and mechanism for C-C bond cleavage are also discussed.

12.
Sci Adv ; 9(37): eadi9108, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37713481

RESUMO

Normally, stirring is regarded as a technology to disperse the substances in liquid evenly. However, Einstein's tea leaf paradox (ETLP) describes the phenomenon that tea leaves concentrate in a "doughnut" shape via a secondary flow effect while stirring. Herein, to demonstrate ETLP-induced concentration in nanofluid, we simulated the nanoparticle trajectory under stirring and made a grayscale analysis of SiO2 nanofluids during stirring and standing processes. Unexpectedly, a localized concentration effect in the layer flow was found beside the macroscopic ETLP effect. Subsequently, the localized concentration was applied to achieve the ultrafast aggregation of Au nanoparticles to form gold aerogels (GAs). The skeleton size of GAs was adjusted from about 10 to 200 nm by only adjusting the temperature of HAuCl4 solution. The fabricated GAs had extremely high purity and crystallinity, revealing potential applications in photocatalysis and surface-enhanced Raman scattering.

13.
Materials (Basel) ; 16(18)2023 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-37763535

RESUMO

This paper presents the results of a test of epoxy anticorrosion coating repair. Two strategies of coating repair were studied, respectively: partial repair and integral repair. The gloss loss rate, color difference and rust area rate of the repair coating were measured. The anticorrosion performance of repair coatings under different repair methods was compared. Based on the results of the coating repair test, the repair criteria for coatings were defined, and the repair strategy for epoxy anticorrosive coatings on steel structure was proposed. The results show that Marathon 500 super abrasion resistant epoxy paint (M500) and Jotamastic 90 GF low surface treatment epoxy abrasion resistant glass flake paint (J90GF) are suitable for partial repair of epoxy anticorrosive coatings on steel structures, and that Jotamastic 90 low surface treatment epoxy abrasion resistant coating (J90) and Marathon 500 super abrasion resistant epoxy paint (M500) are suitable for integral repair of epoxy anticorrosive coatings on steel structures.

14.
ACS Nano ; 17(21): 21093-21104, 2023 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-37643288

RESUMO

Nanopore sensing of proteomic biomarkers lacks accuracy due to the ultralow abundance of targets, a wide variety of interferents in clinical samples, and the mismatch between pore and analyte sizes. By converting antigens to DNA probes via click chemistry and quantifying their characteristic signals, we show a nanopore assay with several amplification mechanisms to achieve an attomolar level limit of detection that enables quantitation of the circulating Mycobacterium tuberculosis (Mtb) antigen ESAT-6/CFP-10 complex in human serum. The assay's nonsputum-based feature and low-volume sample requirements make it particularly well-suited for detecting pediatric tuberculosis (TB) disease, where establishing an accurate diagnosis is greatly complicated by the paucibacillary nature of respiratory secretions, nonspecific symptoms, and challenges with sample collection. In the clinical assessment, the assay was applied to analyze ESAT-6/CFP-10 levels in serum samples collected during baseline investigation for TB in 75 children, aged 0-12 years, enrolled in a diagnostic study conducted in Cape Town, South Africa. This nanopore assay showed superior sensitivity in children with confirmed TB (94.4%) compared to clinical "gold standard" diagnostic technologies (Xpert MTB/RIF 44.4% and Mtb culture 72.2%) and filled the diagnostic gap for children with unconfirmed TB, where these traditional technologies fell short. We envision that, in combination with automated sample processing and portable nanopore devices, this methodology will offer a powerful tool to support the diagnosis of pulmonary TB in children.


Assuntos
Mycobacterium tuberculosis , Nanoporos , Tuberculose Pulmonar , Tuberculose , Humanos , Criança , África do Sul , Proteômica , Sensibilidade e Especificidade , Tuberculose Pulmonar/diagnóstico , Tuberculose/diagnóstico
15.
Phys Chem Chem Phys ; 25(32): 21428-21435, 2023 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-37538025

RESUMO

In the marine environment, Na+ ions have been the focus of attention owing to their high content, which is one of the important factors causing marine corrosion. With reference to the content of macro ions in seawater, circular iron samples were semi-immersed in 0.04 M MgCl2 and 0.6 M NaCl solutions containing different proportions of ethanol. Unexpectedly, we observed more severe corrosion effects in the gas phase region and at the gas-liquid interface of metal samples semi-immersed in the MgCl2 solution. Although the concentration of the MgCl2 solution was only 1/15 of that of the NaCl solution, the iron corrosion induced by MgCl2 was significantly more severe than that caused by NaCl when the ethanol content was increased. Mg2+ ions outperform Na+ ions in metal gas phase corrosion. Especially in the oxygen content of the gas phase corrosion product, MgCl2 caused an increase by up to 52.7%, while NaCl only resulted in a 10.3% increase. Ethanol is normally regarded as a corrosion inhibitor and exists in the liquid phase. Interestingly, in the gas phase and at the gas-liquid interface, ethanol aggravated rather than reducing iron corrosion, particularly in the presence of Mg2+ ions. In addition, we observed that Ca2+ ions produced more severe corrosion effects.

16.
Natl Sci Rev ; 10(7): nwad147, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37416318

RESUMO

Fabricating highly crystalline macroscopic films with extraordinary electrical and thermal conductivities from graphene sheets is essential for applications in electronics, telecommunications and thermal management. High-temperature graphitization is the only method known to date for the crystallization of all types of carbon materials, where defects are gradually removed with increasing temperature. However, when using graphene materials as precursors, including graphene oxide, reduced graphene oxide and pristine graphene, even lengthy graphitization at 3000°C can only produce graphene films with small grain sizes and abundant structural disorders, which limit their conductivities. Here, we show that high-temperature defects substantially accelerate the grain growth and ordering of graphene films during graphitization, enabling ideal AB stacking as well as a 100-fold, 64-fold and 28-fold improvement in grain size, electrical conductivity and thermal conductivity, respectively, between 2000°C and 3000°C. This process is realized by nitrogen doping, which retards the lattice restoration of defective graphene, retaining abundant defects such as vacancies, dislocations and grain boundaries in graphene films at a high temperature. With this approach, a highly ordered crystalline graphene film similar to highly oriented pyrolytic graphite is fabricated, with electrical and thermal conductivities (∼2.0 × 104 S cm-1; ∼1.7 × 103 W m-1 K-1) that are improved by about 6- and 2-fold, respectively, compared to those of the graphene films fabricated by graphene oxide. Such graphene film also exhibits a superhigh electromagnetic interference shielding effectiveness of ∼90 dB at a thickness of 10 µm, outperforming all the synthetic materials of comparable thickness including MXene films. This work not only paves the way for the technological application of highly conductive graphene films but also provides a general strategy to efficiently improve the synthesis and properties of other carbon materials such as graphene fibers, carbon nanotube fibers, carbon fibers, polymer-derived graphite and highly oriented pyrolytic graphite.

17.
Front Immunol ; 14: 1161538, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37287989

RESUMO

KRAS mutation is a significant driving factor of tumor, and KRASG12V mutation has the highest incidence in solid tumors such as pancreatic cancer and colorectal cancer. Thus, KRASG12V neoantigen-specific TCR-engineered T cells could be a promising cancer treatment approach for pancreatic cancer. Previous studies had reported that KRASG12V-reactive TCRs originated from patients' TILs could recognized KRASG12V neoantigen presented by specific HLA subtypes and remove tumor persistently in vitro and in vivo. However, TCR drugs are different from antibody drugs in that they are HLA-restricted. The different ethnic distribution of HLA greatly limits the applicability of TCR drugs in Chinese population. In this study, we have identified a KRASG12V-specific TCR which recognized classII MHC from a colorectal cancer patient. Interestingly, we observed that KRASG12V-specific TCR-engineered CD4+ T cells, not CD8+ T cells, demonstrated significant efficacy in vitro and in xenograft mouse model, exhibiting stable expression and targeting specificity of TCR when co-cultured with APCs presenting KRASG12V peptides. TCR-engineered CD4+ T cells were co-cultured with APCs loaded with neoantigen, and then HLA subtypes were identified by the secretion of IFN-γ. Collectively, our data suggest that TCR-engineered CD4+ T cells can be used to target KRASG12V mutation presented by HLA-DPB1*03:01 and DPB1*14:01, which provide a high population coverage and are more suitable for the clinical transformation for Chinese, and mediate tumor killing effect like CD8+ T cells. This TCR hold promise for precision therapy in immunotherapy of solid tumors as an attractive candidate.


Assuntos
Neoplasias Colorretais , Neoplasias Pancreáticas , Humanos , Camundongos , Animais , Proteínas Proto-Oncogênicas p21(ras)/genética , Antígenos de Neoplasias , Receptores de Antígenos de Linfócitos T , Mutação , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/terapia , Imunoterapia , Neoplasias Pancreáticas
18.
Sensors (Basel) ; 23(11)2023 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-37299960

RESUMO

Automatic Modulation Recognition (AMR) can obtain the modulation mode of the received signal for subsequent processing without the assistance of the transmitter. Although the existing AMR methods have been mature for the orthogonal signals, these methods face challenges when deployed in non-orthogonal transmission systems due to the superimposed signals. In this paper, we aim to develop efficient AMR methods for both downlink and uplink non-orthogonal transmission signals using deep learning-based data-driven classification methodology. Specifically, for downlink non-orthogonal signals, we propose a Bi-directional Long Short-Term Memory (BiLSTM)-based AMR method that exploits long-term data dependence to automatically learn irregular signal constellation shapes. Transfer learning is further incorporated to improve recognition accuracy and robustness under varying transmission conditions. For uplink non-orthogonal signals, the combinatorial number of classification types explodes exponentially with the number of signal layers, which becomes the major obstacle to AMR. We develop a spatio-temporal fusion network based on the attention mechanism to efficiently extract spatio-temporal features, and network details are optimized according to the superposition characteristics of non-orthogonal signals. Experiments show that the proposed deep learning-based methods outperform their conventional counterparts in both downlink and uplink non-orthogonal systems. In a typical uplink scenario with three non-orthogonal signal layers, the recognition accuracy can approach 96.6% in the Gaussian channel, which is 19% higher than the vanilla Convolution Neural Network.


Assuntos
Aprendizado Profundo , Memória de Longo Prazo , Redes Neurais de Computação , Distribuição Normal , Reconhecimento Psicológico
19.
JACS Au ; 3(3): 801-812, 2023 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-37006771

RESUMO

The C-N bond cleavage represents one kind of important organic and biochemical transformation, which has attracted great interest in recent years. The oxidative cleavage of C-N bonds in N,N-dialkylamines into N-alkylamines has been well documented, but it is challenging in the further oxidative cleavage of C-N bonds in N-alkylamines into primary amines due to the thermally unfavorable release of α-position H from N-Cα-H and the paralleling side reactions. Herein, a biomass-derived single Zn atom catalyst (ZnN4-SAC) was discovered to be a robust heterogeneous non-noble catalyst for the oxidative cleavage of C-N bonds in N-alkylamines with O2 molecules. Experimental results and DFT calculation revealed that ZnN4-SAC not only activates O2 to generate superoxide radicals (·O2 -) for the oxidation of N-alkylamines to generate imine intermediates (C=N), but the single Zn atoms also served as the Lewis acid sites to promote the cleavage of C=N bonds in imine intermediates, including the first addition of H2O to generate α-hydroxylamine intermediates and the following C-N bond cleavage via a H atom transfer process.

20.
Int J Surg ; 109(7): 1941-1952, 2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37026827

RESUMO

BACKGROUND: Patients with resected pancreatic adenocarcinoma (PAAD) often experience short-term relapse and dismal survival, suggesting an urgent need to develop predictive and/or prognostic biomarkers for these populations. Given the potential associations of the human leukocyte antigen class I ( HLA -I) genotype with oncogenic mutational profile and immunotherapy efficacy, we aimed to assess whether differential HLA -I genotype could predict the postoperative outcomes in resected PAAD patients. MATERIALS AND METHODS: HLA -I ( A , B , and C ) genotyping and somatic variants of 608 Chinese PAAD patients were determined by targeted next-generation sequencing of matched blood cells and tumor tissues. HLA - A / B alleles were classified with the available definition of 12 supertypes. The Kaplan-Meier curves of disease-free survival (DFS) and multivariable Cox proportional-hazards regression analyses were performed to determine the survival difference in 226 selected patients with radical resection. Early-stage (I-II) patients constituted the majority (82%, 185/226) and some stage I-II individuals with high-quality tumor samples were analyzed by RNA-sequencing to examine immunophenotypes. RESULTS: Patients with HLA-A02 + B62 + B44 - had significantly shorter DFS (median, 239 vs. 410 days; hazard ratio=1.65, P =0.0189) than patients without this genotype. Notably, stage I-II patients carrying HLA-A02 + B62 + B44 - had sharply shorter DFS than those without HLA-A02 + B62 + B44 - (median, 237 vs. 427 days; hazard ratio=1.85, P =0.007). Multivariate analysis revealed that HLA-A02 + B62 + B44 - was associated with significantly inferior DFS ( P =0.014) in stage I-II patients but not in stage III patients. Mechanistically, HLA-A02 + B62 + B44 - patients were associated with a high rate of KRAS G12D and TP53 mutations, lower HLA-A expression, and less inflamed T-cell infiltration. CONCLUSION: The current results suggest that a specific combination of germline HLA-A02/B62/B44 supertype, HLA-A02 + B62 + B44 - , was a potential predictor for DFS in early-stage PAAD patients after surgery.


Assuntos
Adenocarcinoma , Neoplasias Pancreáticas , Humanos , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/cirurgia , Adenocarcinoma/diagnóstico , Adenocarcinoma/genética , Adenocarcinoma/cirurgia , Genótipo , Estudos Retrospectivos , Antígenos HLA , População do Leste Asiático
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