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1.
Bioorg Chem ; 150: 107612, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38986418

RESUMO

The high level of tyrosinase leads to the generation of neuromelanin, further causing the abnormality of redox-related protein level and mediating the occurrence and development of Parkinson's disease (PD). However, the existing tyrosinase inhibitors are mostly natural product extracts or polyphenolic derivatives, which hindered them from penetrating the blood-brain barrier (BBB). Herein, we obtained a novel tyrosinase inhibitor, 2-06 (tyrosinase: monophenolase IC50 = 70.44 ± 22.69 µM, diphenolase IC50 = 1.89 ± 0.64 µM), through the structure-based screening method. The compound 2-06 presented good in vitro and in vivo safety, and can inhibit the tyrosinase and melanogenesis in B16F10. Moreover, this compound showed neuroprotective effects and Parkinsonism behavior improving function. 2-06 was proved to penetrate the BBB and enter the central nervous system (CNS). The exploration of the binding mode between 2-06 and tyrosinase provided the foundation for the subsequent structural optimization. This is the first research to develop a central-targeting tyrosinase inhibitor, which is crucial for in-depth study on the new strategy for utilizing tyrosinase inhibitors to treat PD.

3.
Endosc Ultrasound ; 13(2): 100-106, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38947749

RESUMO

Background and Objective: To compare the efficacy of EUS-guided celiac plexus neurolysis (CPN) and celiac plexus irradiation with iodine-125 (125I) seeds with absolute ethanol for relieving pain in patients with advanced pancreatic cancer. Methods: We retrospectively analyzed data of 81 patients with advanced pancreatic cancer who underwent EUS-CPN or EUS-125I implantation between January 2017 and December 2020. Postoperative pain was assessed using visual analog scale (VAS) scores; self-assessments of quality of life and the median survival time were compared between the 2 groups. Results: EUS-CPN and 125I implantation were performed in 43 and 38 patients, respectively. Postoperative VAS scores were significantly lower than the preoperative levels in both groups. One week after the operation, 26 patients (60.5%) in the EUS-CPN group achieved partial pain relief, whereas no patients in the EUS-125I seed group experienced pain relief. However, after 4 weeks postoperatively, VAS scores had decreased, and the rate of partial pain relief was higher for EUS-125I seeds than for EUS-CPN. Self-assessments of quality of life were similar in both groups during the first 1 month after the procedure. Conclusions: Both EUS-CPN and EUS-125I seeds can safely and effectively relieve pain in patients with advanced pancreatic cancer. Although EUS-125I seeds take additional time to show effects, the extent and duration of pain relief are better compared with CPN, and interestingly, the median survival time was different.

4.
J Nanobiotechnology ; 22(1): 400, 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38972995

RESUMO

Considerable attention has been directed towards exploring the potential efficacy of miR-155 in the realm of cancer immunotherapy. Elevated levels of miR-155 in dendritic cells (DCs) have been shown to enhance their maturation, migration, cytokine secretion, and their ability to promote T cell activation. In addition, overexpression of mir155 in M2 macrophages boost the polarization towards the M1 phenotype. Conversely, miR-155 has the propensity to induce the accumulation of immunosuppressive cells like regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) in the tumor tissue. To account for this discrepancy, it is imperative to get help from a drug that could deal with immunosuppressive effect. Curcumin (CUR) exhibits the capacity to prompt Tregs converse into T helper 1 cells, fostering the polarization of M2 tumor-associated macrophage towards the M1 phenotype, and impeding the recruitment and aggregation of MDSCs within the tumor microenvironment. Nonetheless, CUR is known to exert an immunosuppressive impact on DCs by hindering the expression of maturation markers, cytokines, and chemokines, thereby prevent DCs response to immunostimulatory agents. Hence, a reactive oxygen species/glutathione dual responsive drug conveyance platform (CUR/miR155@DssD-Hb NPs) was devised to co-deliver CUR and miR155, with the aim of exploring their synergistic potential in bolstering a sustained and robust anti-tumor immune response. In vitro and in vivo results have suggested that CUR/miR155@DssD-Hb NPs can effectively inhibit the viability of 4T1 and B16F10 tumor cells, trigger the release of damage associated molecular patterns, stimulate DCs maturation, subsequent activation of CD8+ T cells, diminish immunosuppressive cell populations (MDSCs, Tregs, M2 TAMs and exhausted T cells), promote the formation of long-term immunity and lessen the formation of metastatic nodules in the lungs. In summary, the co-delivery system integrating CUR and miR155 (CUR/miR155@DssD-Hb NPs) demonstrates promise as a promising strategy for the immunotherapy of melanoma and triple negative breast cancer.


Assuntos
Curcumina , Células Dendríticas , Imunoterapia , MicroRNAs , Nanopartículas , Espécies Reativas de Oxigênio , Curcumina/farmacologia , Curcumina/química , MicroRNAs/genética , Animais , Camundongos , Nanopartículas/química , Espécies Reativas de Oxigênio/metabolismo , Imunoterapia/métodos , Células Dendríticas/metabolismo , Células Dendríticas/imunologia , Células Dendríticas/efeitos dos fármacos , Linhagem Celular Tumoral , Feminino , Camundongos Endogâmicos C57BL , Microambiente Tumoral/efeitos dos fármacos , Camundongos Endogâmicos BALB C , Macrófagos/metabolismo , Macrófagos/efeitos dos fármacos , Humanos , Neoplasias/terapia , Neoplasias/tratamento farmacológico , Neoplasias/imunologia
5.
Small Methods ; : e2400530, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-39007247

RESUMO

Lattice-confined single-atom catalyst (LC SAC), featuring exceptional activity, intriguing stability and prominent selectivity, has attracted extensive attention in the fields of various reactions (e.g., hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), etc.). To design a "smart" LC SAC for catalytic applications, one must systematically comprehend updated advances in the preparation, the application, and especially the peculiar electron regulation mechanism of LC SAC. In this review, the specific preparation methods of LC SAC based on general coordination strategy are updated, and its applications in HER, OER, ORR, N2 reduction reaction (NRR), advanced oxidation processes (AOPs) and so forth are summarized to display outstanding activity, stability and selectivity. Uniquely, the electron regulation mechanisms are first and deeply discussed and can be primarily categorized as electron transfer bridge with monometallic active sites, novel catalytic centers with polymetallic active sites, and positive influence by surrounding environments. In the end, the existing issues and future development directions are put forward with a view to further optimize the performance of LC SAC. This review is expected to contribute to the in-depth understanding and practical application of highly efficient LC SAC.

6.
Nat Prod Res ; : 1-28, 2024 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-38910339

RESUMO

Alzheimer's disease (AD) is the most common neurodegenerative disease, which is mainly caused by the damage of the structure and function of the central nervous system. At present, there are many adverse reactions in market-available drugs, which can't significantly inhibit the occurrence of AD. Therefore, the current focus of research is to find safe and effective therapeutic drugs to improve the clinical treatment of AD. Oxidative stress bridges different mechanism hypotheses of AD and plays a key role in AD. Numerous studies have shown that natural flavonoids have good antioxidant effects. They can directly or indirectly resist -oxidative stress, inhibit Aß aggregation and Tau protein hyperphosphorylation by activating Nrf2 and other oxidation-antioxidation-related signals, regulating synaptic function-related pathways, promoting mitochondrial autophagy, etc., and play a neuroprotective role in AD. In this review, we summarised the mechanism of flavonoids inhibiting oxidative stress injury in AD in recent years. Moreover, because of the shortcomings of poor biofilm permeability and low bioavailability of flavonoids, the advantages and recent research progress of nano-drug delivery systems such as liposomes and solid lipid nanoparticles were highlighted. We hope this review provides a useful way to explore safe and effective AD treatments.

7.
Front Pharmacol ; 15: 1408135, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38939844

RESUMO

Background: Tivozanib, a vascular endothelial growth factor tyrosine kinase inhibitor, has demonstrated efficacy in a phase III clinical trials for the treatment of renal cell carcinoma. However, comprehensive evaluation of its long-term safety profile in a large sample population remains elusive. The current study assessed Tivozanib-related adverse events of real-world through data mining of the US Food and Drug Administration Adverse Event Reporting System FDA Adverse Event Reporting System. Methods: Disproportionality analyses, utilizing reporting odds ratio proportional reporting ratio Bayesian confidence propagation neural network and multi-item gamma Poisson shrinker (MGPS) algorithms, were conducted to quantify signals of Tivozanib-related AEs. Weibull distribution was used to predict the varying risk incidence of AEs over time. Results: Out of 5,361,420 reports collected from the FAERS database, 1,366 reports of Tivozanib-associated AEs were identified. A total of 94 significant disproportionality preferred terms (PTs) conforming to the four algorithms simultaneously were retained. The most common AEs included fatigue, diarrhea, nausea, blood pressure increased, decreased appetite, and dysphonia, consistent with prior specifications and clinical trials. Unexpected significant AEs such as dyspnea, constipation, pain in extremity, stomatitis, and palmar-plantar erythrodysaesthesia syndrome was observed. The median onset time of Tivozanib-related AEs was 37 days (interquartile range [IQR] 11.75-91 days), with a majority (n = 127, 46.35%) occurring within the initial month following Tivozanib initiation. Conclusion: Our observations align with clinical assertions regarding Tivozanib's safety profile. Additionally, we unveil potential novel and unexpected AE signatures associated with Tivozanib administration, highlighting the imperative for prospective clinical studies to validate these findings and elucidate their causal relationships. These results furnish valuable evidence to steer future clinical inquiries aimed at elucidating the safety profile of Tivozanib.

8.
Artif Intell Med ; 154: 102919, 2024 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-38941908

RESUMO

Pancreatic cancer does not show specific symptoms, which makes the diagnosis of early stages difficult with established image-based screening methods and therefore has the worst prognosis among all cancers. Although endoscopic ultrasonography (EUS) has a key role in diagnostic algorithms for pancreatic diseases, B-mode imaging of the pancreas can be affected by confounders such as chronic pancreatitis, which can make both pancreatic lesion segmentation and classification laborious and highly specialized. To address these challenges, this work proposes a semi-supervised multi-task network (SSM-Net) to leverage unlabeled and labeled EUS images for joint pancreatic lesion classification and segmentation. Specifically, we first devise a saliency-aware representation learning module (SRLM) on a large number of unlabeled images to train a feature extraction encoder network for labeled images by computing a contrastive loss with a semantic saliency map, which is obtained by our spectral residual module (SRM). Moreover, for labeled EUS images, we devise channel attention blocks (CABs) to refine the features extracted from the pre-trained encoder on unlabeled images for segmenting lesions, and then devise a merged global attention module (MGAM) and a feature similarity loss (FSL) for obtaining a lesion classification result. We collect a large-scale EUS-based pancreas image dataset (LS-EUSPI) consisting of 9,555 pathologically proven labeled EUS images (499 patients from four categories) and 15,500 unlabeled EUS images. Experimental results on the LS-EUSPI dataset and a public thyroid gland lesion dataset show that our SSM-Net clearly outperforms state-of-the-art methods.

9.
Sci Data ; 11(1): 667, 2024 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-38909038

RESUMO

Cnidium monnieri, a medicinal herb of the Cnidium genus and the Apiaceae family, is among the most important traditional Chinese medicines and is widely distributed in China. However, to date, no C. monnieri-related genomic information has been described. In this study, we assembled the C. monnieri genome of approximately 1210.23 Mb with a contig N50 of 83.14 Mb. Using PacBio HiFi and Hi-C sequencing data, we successfully anchored 93.86% of the assembled sequences to 10 pseudochromosomes (2n = 20). We predicted a total of 37,460 protein-coding genes, with 97.02% of them being functionally annotated in Non-Redundant, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and other databases. In addition, we identified 2,778 tRNAs, 4,180 rRNAs, 258 miRNAs, and 1,700 snRNAs in the genome. This is the first reported C. monnieri genome. Hopefully, the availability of this chromosome-level reference genome provides a significant basis for upcoming natural product-related biosynthetic pathway assessment in C. monnieri.


Assuntos
Cnidium , Genoma de Planta , Cromossomos de Plantas , Cnidium/genética , Medicina Tradicional Chinesa , Plantas Medicinais/genética
10.
Surg Endosc ; 2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38898340

RESUMO

BACKGROUND: Endoscopic ultrasound-guided pancreatic duct (PD) drainage (EUS-PDD) is being increasingly performed as an alternative method to surgical drainage to achieve PD decompression after failed endoscopic retrograde pancreatography (ERP). However, no directly study has compared EUS-PDD with surgical PD drainage after failed ERP in patients with chronic pancreatitis. METHODS: Consecutive patients who underwent EUS-PDD or longitudinal pancreaticojejunostomy after failed ERP were retrospectively identified from our endoscopy and medical information systems. The primary end point was the Izbicki pain score. The secondary end points were pain relief at the end of follow-up, procedure outcomes, adverse events, readmission, and reintervention. RESULTS: A total of 21 patients (11 EUS-PDD, 10 surgical drainages) were analyzed. There were no significant differences in mean Izbicki pain score (EUS-PDD, 13.6 ± 10.1 vs. surgical drainage 10.7 ± 7.9, p = 0.483) or complete/partial pain relief (60%/30% vs. 70%/30%, p = 0.752) at the end of follow-up of the two groups. The rates of overall adverse events (27.3% vs. 30.0%, p = 0.893) and readmission (63.6% vs. 40.0%, p = 0.290) were similar in the two treatment groups, while patients in EUS-PDD group required more reinterventions (45.5% vs. 0%, p = 0.039) compared with patients in the surgery group. CONCLUSION: EUS-PDD showed comparable pain relief and safety to surgical PD drainage after failed ERP, with a higher rate of reintervention. The selection of EUS-PDD or surgical drainage may be appropriate based on an individualized strategy.

11.
Ocul Immunol Inflamm ; : 1-11, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38709230

RESUMO

PURPOSE: We aimed to evaluate adalimumab efficacy in patients with initial-onset or recurrent Vogt-Koyanagi-Harada (VKH) syndrome. METHODS: A retrospective clinical study was performed to examine the therapeutic effect of adalimumab in 22 VKH patients,16 with initial-onset and six with recurrent VKH. Another 22 patients with initial-onset VKH who did not receive adalimumab were included as controls. The main observational parameters included the central macular thickness (CMT), subfoveal choroidal thickness (SCT), best-corrected visual acuity (BCVA), anterior chamber cell grade (ACC), glucocorticoid dose (GCD), and the development of sunset glow fundus. MRNA sequencing was used to profile the tumor necrosis factor (TNF)-α pathway in peripheral blood mononuclear cells obtained from nine patients with initial-onset VKH disease, six patients with recurrent VKH, and eight healthy controls. RESULTS: In the initial-onset group, adalimumab therapy significantly improved the BCVA, CMT, SCT, and ACC. Furthermore, adalimumab significantly decreased GCD in patients with initial-onset. In patients with recurrent VKH, the SCT significantly improved after adalimumab treatment, but no significant changes in BCVA, CMT, and ACC were observed. All six patients experienced relapse during follow-up. The TNF-α pathway exhibited a significant increase in initial-onset VKH when compared with that in both healthy controls and recurrent patients. Conversely, it was suppressed in recurrent VKH when compared with that in the initial-onset or healthy control groups. CONCLUSIONS: In patients with initial-onset VKH, adalimumab effectively reduces glucocorticoid dependence. However, adalimumab may not be effective for preventing relapse or providing long-term inflammation relief in patients with recurrent VKH.

12.
Adv Sci (Weinh) ; : e2403337, 2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38810101

RESUMO

Sepsis is an infection-triggered, rapidly progressive systemic inflammatory syndrome with a high mortality rate. Currently, there are no promising therapeutic strategies for managing this disease in the clinic. Heparanase plays a crucial role in the pathology of sepsis, and its inhibition can significantly relieve related symptoms. Here, a novel heparanase inhibitor CV122 is rationally designed and synthesized, and its therapeutic potential for sepsis with Lipopolysaccharide (LPS) and Cecal Ligation and Puncture (CLP)-induced sepsis mouse models are evaluated. It is found that CV122 potently inhibits heparanase activity in vitro, protects cell surface glycocalyx structure, and reduces the expression of adhesion molecules. In vivo, CV122 significantly reduces the systemic levels of proinflammatory cytokines, prevents organ damage, improves vitality, and efficiently protects mice from sepsis-induced death. Mechanistically, CV122 inhibits the activity of heparanase, reduces its expression in the lungs, and protects glycocalyx structure of lung tissue. It is also found that CV122 provides effective protection from organ damage and death caused by Crimean-Congo hemorrhagic fever virus (CCHFV) infection. These results suggest that CV122 is a potential drug candidate for sepsis therapy targeting heparanase by inhibiting cytokine storm.

14.
Chemistry ; 30(39): e202401243, 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-38711202

RESUMO

Axially chiral cycloalkylidenes are interesting but less developed axially chiral molecules. Here, a bispidine-based chiral amine catalytic system was developed to promote efficiently the asymmetric Knoevenagel condensation of N-protected oxindoles and benzofuranones with 4-substituted cyclohexanones. A variety of alkylidenecycloalkanes with stable axial chirality were obtained in good yields and fairly good er (enantiomeric ratio). Based on the absolute configuration determination of product and DFT calculations, a possible mechanism of stereoselective induction was proposed.

15.
Plants (Basel) ; 13(6)2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38592894

RESUMO

Fusarium crown rot (FCR), primarily caused by Fusarium pseudograminearum, has emerged as a new threat to wheat production and quality in North China. Genetic enhancement of wheat resistance to FCR remains the most effective approach for disease control. In this study, we phenotyped 435 Chinese wheat cultivars through FCR inoculation at the seedling stage in a greenhouse. Our findings revealed that only approximately 10.8% of the wheat germplasms displayed moderate or high resistance to FCR. A genome-wide association study (GWAS) using high-density 660K SNP led to the discovery of a novel quantitative trait locus on the long arm of chromosome 3B, designated as Qfcr.hebau-3BL. A total of 12 significantly associated SNPs were closely clustered within a 1.05 Mb physical interval. SNP-based molecular markers were developed to facilitate the practical application of Qfcr.hebau-3BL. Among the five candidate FCR resistance genes within the Qfcr.hebau-3BL, we focused on TraesCS3B02G307700, which encodes a protein kinase, due to its expression pattern. Functional validation revealed two transcripts, TaSTK1.1 and TaSTK1.2, with opposing roles in plant resistance to fungal disease. These findings provide insights into the genetic basis of FCR resistance in wheat and offer valuable resources for breeding resistant varieties.

16.
BMC Ophthalmol ; 24(1): 196, 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38671401

RESUMO

BACKGROUND: The aim of this study was to report the clinical profile of new-onset and relapse of uveitis following rapid spreading of coronavirus disease 2019 (COVID-19) infection due to change of anti-COVID-19 policies in China and investigate potential risk factors for inflammation relapse. METHODS: In this retrospective case-control study, patients with new-onset or a history of uveitis between December 23, 2022, and February 28, 2023, were included to assess the influence of COVID-19 infection on uveitis. Detailed information on demographic data, clinical characteristics, treatment measures, treatment response, and ocular inflammatory status before and after COVID-19 infection was collected. RESULTS: This study included 349 patients with a history of uveitis. The uveitis relapse rate was higher (28.8%, n = 288) in those with COVID-19 infection than in patients without COVID-19 infection (14.8%, n = 61) (P = 0.024). Among the relapse cases, 50.8% experienced a relapse of anterior uveitis, while 49.2% had a relapse of uveitis involving the posterior segment. Multivariable regression analysis indicated a positive correlation between disease duration and uveitis relapse, while the last relapse exceeding one year before COVID-19 infection and the use of methotrexate during COVID-19 infection were negatively correlated with relapse of uveitis. Thirteen patients who developed new-onset uveitis following COVID-19 infection were included; among them, three (23.1%) had anterior uveitis and 10 (76.9%) had uveitis affecting the posterior segment. Regarding cases involving the posterior segment, four patients (30.8%) were diagnosed with Vogt-Koyanagi-Harada disease. CONCLUSIONS: COVID-19 infection increases the rate of uveitis relapse. Long disease duration is a risk factor, while time since the last relapse more than 1 year and methotrexate use are protective factors against uveitis relapse.


Assuntos
COVID-19 , Recidiva , SARS-CoV-2 , Uveíte , Humanos , COVID-19/epidemiologia , COVID-19/complicações , Masculino , Feminino , Estudos Retrospectivos , China/epidemiologia , Fatores de Risco , Uveíte/diagnóstico , Uveíte/epidemiologia , Uveíte/etiologia , Uveíte/tratamento farmacológico , Pessoa de Meia-Idade , Adulto , Estudos de Casos e Controles , Idoso
17.
Opt Lett ; 49(8): 1993-1996, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38621059

RESUMO

Unsupervised spectral reconstruction (SR) aims to recover the hyperspectral image (HSI) from corresponding RGB images without annotations. Existing SR methods achieve it from a single RGB image, hindered by the significant spectral distortion. Although several deep learning-based methods increase the SR accuracy by adding RGB images, their networks are always designed for other image recovery tasks, leaving huge room for improvement. To overcome this problem, we propose a novel, to our knowledge, approach that reconstructs the HSI from a pair of RGB images captured under two illuminations, significantly improving reconstruction accuracy. Specifically, an SR iterative model based on two illuminations is constructed at first. By unfolding the proximal gradient algorithm solving this SR model, an interpretable unsupervised deep network is proposed. All the modules in the proposed network have precise physical meanings, which enable our network to have superior performance and good generalization capability. Experimental results on two public datasets and our real-world images show the proposed method significantly improves both visually and quantitatively as compared with state-of-the-art methods.

18.
Anal Chim Acta ; 1302: 342492, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38580406

RESUMO

The rational design of DNA tracks is an effective pathway to guide the autonomous movement and high-efficiency recognition in DNA walkers, showing outstanding advantages for the cascade signal amplification of electrochemical biosensors. However, the uncontrolled distance between two adjacent tracks on the electrode could increase the risk of derailment and interruption of the reaction. Hence, a novel four-way balanced cruciform-shaped DNA track (C-DNT) was designed as a structured pathway to improve the effectiveness and stability of the reaction in DNA walkers. In this work, two kinds of cruciform-shaped DNA were interconnected as a robust structure that could avoid the invalid movement of the designed DNA walker on the electrode. When hairpin H2 was introduced onto the electrode, the strand displacement reaction (SDR) effectively triggered movements of the DNA walker along the cruciform-shaped track while leaving ferrocene (Fc) on the electrode, leading to a significant enhancement of the electrochemical signal. This design enabled the walker to move in an excellent organized and controllable manner, thus enhancing the reaction speed and walking efficiency. Compared to other walkers moving on random tracks, the reaction time of the C-DNT-based DNA walker could be reduced to 20 min. Lead ion (Pb2+) was used as a model target to evaluate the analytical performance of this biosensor, which exhibited a low detection limit of 0.033 pM along with a wide detection ranging from 0.1 pM to 500 nM. This strategy presented a novel concept for designing a high-performance DNA walker-based sensing platform for the detection of contaminants.


Assuntos
Técnicas Biossensoriais , Chumbo , DNA Cruciforme , Limite de Detecção , DNA/química , Técnicas Eletroquímicas
19.
J Colloid Interface Sci ; 666: 66-75, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-38583211

RESUMO

Perovskite CsPbBr3 quantum dot shows great potential in artificial photosynthesis, attributed to its outstanding optoelectronic properties. Nevertheless, its photocatalytic activity is hindered by insufficient catalytic active sites and severe charge recombination. In this work, a CsPbBr3@Ag-C3N4 ternary heterojunction photocatalyst is designed and synthesized for high-efficiency CO2 reduction. The CsPbBr3 quantum dots and Ag nanoparticles are chemically anchored on the surface of g-C3N4 sheets, forming an electron transfer tunnel from CsPbBr3 quantum dots to Ag nanoparticles via g-C3N4 sheets. The resulting CsPbBr3@Ag-C3N4 ternary photocatalyst, with spatial separation of photogenerated carriers, achieves a remarkable conversion rate of 19.49 µmol·g-1·h-1 with almost 100 % CO selectivity, a 3.13-fold enhancement in photocatalytic activity as compared to CsPbBr3 quantum dots. Density functional theory calculations reveal the rapid CO2 adsorption/activation and the decreased free energy (0.66 eV) of *COOH formation at the interface of Ag nanoparticles and g-C3N4 in contrast to the g-C3N4, leading to the excellent photocatalytic activity, while the thermodynamically favored CO desorption contributes to the high CO selectivity. This work presents an innovative strategy of constructing perovskite-based photocatalyst by modulating catalyst structure and offers profound insights for efficient CO2 conversion.

20.
Phytochemistry ; 222: 114102, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38641144

RESUMO

Furanocoumarins (FCs) are widely distributed secondary metabolites found in higher plants, including Apiaceae, Rutaceae, Moraceae, and Fabaceae. They play a crucial role in the physiological functions of plants and are well-known for their diverse pharmacological activities. As a representative plant of the Apiaceae family, Angelica sinensis is highly valued for its medicinal properties and FCs are one of the main ingredients of A. sinensis. However, the biosynthetic mechanism of FCs in A. sinensis remains poorly understood. In this study, we successfully cloned and verified three types of enzymes using genome analysis and in vitro functional verification, which complete the biosynthesis of the FCs core skeleton in A. sinensis. It includes a p-coumaroyl CoA 2'-hydroxylase (AsC2'H) responsible for umbelliferone formation, two UbiA prenyltransferases (AsPT1 and AsPT2) that convert umbelliferone to demethylsuberosin (DMS) and osthenol, respectively, and two CYP736 subfamily cyclases (AsDC and AsOD) that catalyze the formation of FCs core skeleton. Interestingly, AsOD was demonstrated to be a bifunctional cyclase and could catalyze both DMS and osthenol, but had a higher affinity to osthenol. The characterization of these enzymes elucidates the molecular mechanism of FCs biosynthesis, providing new insights and technologies for understanding the diverse origins of FCs biosynthesis.


Assuntos
Angelica sinensis , Furocumarinas , Furocumarinas/química , Furocumarinas/metabolismo , Furocumarinas/biossíntese , Angelica sinensis/química , Angelica sinensis/metabolismo , Estrutura Molecular
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