Your browser doesn't support javascript.
loading
Montrer: 20 | 50 | 100
Résultats 1 - 20 de 855
Filtrer
1.
Small ; : e2403176, 2024 Jul 01.
Article de Anglais | MEDLINE | ID: mdl-38949041

RÉSUMÉ

Atomic Ag cluster bonding is employed to reinforce the interface between PF3T nano-cluster and TiO2 nanoparticle. With an optimized Ag loading (Ag/TiO2 = 0.5 wt%), the Ag atoms will uniformly disperse on TiO2 thus generating a high density of intermediate states in the band gap to form the electron channel between the terthiophene group of PF3T and the TiO2 in the hybrid composite (denoted as T@Ag05-P). The former expands the photon absorption band width and the latter facilitates the core-hole splitting by injecting the photon excited electron (from the excitons in PF3T) into the conduction band (CB) of TiO2. These characteristics enable the high efficiency of H2 production to 16 580 µmol h-1 g-1 and photocatalysis stability without degradation under visible light exposure for 96 h. Compared to that of hybrid material without Ag bonding (TiO2@PF3T), the H2 production yield and stability are improved by 4.1 and 18.2-fold which shows the best performance among existing materials in similar component combination and interfacial reinforcement. The unique bonding method offers a new prospect to accelerate the development of photocatalytic hydrogen production technologies.

2.
Ageing Res Rev ; 98: 102347, 2024 07.
Article de Anglais | MEDLINE | ID: mdl-38815933

RÉSUMÉ

Aging, a complex biological process, plays key roles the development of multiple disorders referred as aging-related diseases involving cardiovascular diseases, stroke, neurodegenerative diseases, cancers, lipid metabolism-related diseases. ADP-ribosylation is a reversible modification onto proteins and nucleic acids to alter their structures and/or functions. Growing evidence support the importance of ADP-ribosylation and ADP-ribosylation-associated enzymes in aging and age-related diseases. In this review, we summarized ADP-ribosylation-associated proteins including ADP-ribosyl transferases, the ADP-ribosyl hydrolyses and ADP-ribose binding domains. Furthermore, we outlined the latest knowledge about regulation of ADP-ribosylation in the pathogenesis and progression of main aging-related diseases, organism aging and cellular senescence, and we also speculated the underlying mechanisms to better disclose this novel molecular network. Moreover, we discussed current issues and provided an outlook for future research, aiming to revealing the unknown bio-properties of ADP-ribosylation, and establishing a novel therapeutic perspective in aging-related diseases and health aging via targeting ADP-ribosylation.


Sujet(s)
ADP-Ribosylation , Vieillissement , Humains , Vieillissement/métabolisme , Vieillissement/physiologie , ADP-Ribosylation/physiologie , Animaux , Vieillissement de la cellule/physiologie , Maladies neurodégénératives/métabolisme
3.
Chem Commun (Camb) ; 60(46): 5948-5951, 2024 Jun 04.
Article de Anglais | MEDLINE | ID: mdl-38764410

RÉSUMÉ

Structurally symmetric dyes using functionalized fluorenes and benzotriazole as the main building moieties have been synthesized and found to exhibit efficient dual-state emission (DSE) and interesting two-wavelength or dual amplified spontaneous emission (dual-ASE) behaviors in the solution phase, which may benefit the development of organic gain materials with dual-wavelength amplification.

4.
Article de Chinois | WPRIM (Pacifique Occidental) | ID: wpr-1006418

RÉSUMÉ

Budd-Chiari syndrome is a rare liver vascular disease and can be classified into hepatic vein occlusion type, inferior vena cava occlusion type, and mixed type according to the location of hepatic outflow tract obstruction. This article reviews the hepatic vein occlusion type from the aspects of epidemiology, subtypes, clinical diagnosis, and treatment strategies.

5.
Article de Chinois | WPRIM (Pacifique Occidental) | ID: wpr-1017170

RÉSUMÉ

ObjectiveTo observe the clinical efficacy of modified Zuojinwan granules in treating reflux esophagitis (RE) and functional dyspepsia (FD) with the same syndrome with disharmony between liver and stomach). MethodA randomized double-blind placebo-controlled clinical trial was conducted to enroll 144 patients with disharmony between liver and stomach, including 72 patients with RE and 72 patients with FD. These patients were then randomly divided into observation and control groups, with 36 patients in each group. The observation group was given modified Zuojinwan granules orally, and the control group was given placebo granules orally. They both were treated with two packs each time, twice a day, for four weeks. The traditional Chinese medicine (TCM) syndrome scores, cerebrointestinal peptides [calcitonin gene-associated titanium (CGRP), vasoactive intestinal peptide (VIP), 5-hydroxytryptamine (5-HT), and substance P (SP)], inflammatory factors [tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6)], common gastrointestinal related hormones [gastrin (GAS) and motilin (MTL)], and other indicators in the two groups were compared before and after treatment, and the curative effect of TCM syndromes and the occurrence of adverse reactions were determined. At the same time, the changes in the above indicators and the curative effect of TCM syndromes in the two groups of patients with the same disease were analyzed. ResultAfter treatment, CGRP, VIP, 5-HT, SP, TNF-α, IL-6, GAS, MTL, and TCM syndrome scores in the observation group and control group were significantly improved (P<0.05). After treatment, the improvement of CGRP, VIP, 5-HT, SP, TNF-α, IL-6, GAS, MTL, and TCM syndrome scores in the observation group was better than that in the control group (P<0.05). After treatment, CGRP, VIP, 5-HT, SP, TNF-α, IL-6, GAS, MTL, and TCM syndrome scores in both groups of RE patients and FD patients were significantly improved (P<0.05). After treatment, the improvement of CGRP, VIP, 5-HT, SP, TNF-α, IL-6, GAS, MTL, and TCM syndrome scores in RE patients and FD patients in the observation group were better than that in the control group (P<0.05). In the observation group and the control group, the incidence of nausea, vomiting, fatigue, dry mouth, and other adverse reactions was lower, and there was no statistical significance. ConclusionModified Zuojinwan granules can effectively improve the TCM syndromes of disharmony between liver and stomach of RE and FD, brain and intestinal peptide, gastrointestinal hormone, and inflammatory factors and provide evidence for the clinical application of TCM theory of "treating different diseases with the same method".

6.
Article de Chinois | WPRIM (Pacifique Occidental) | ID: wpr-1017319

RÉSUMÉ

Objective:To discuss the regulatory effect of berberine(BBR)on fatty acids in the human glioma T98G cells and its effect on the cell proliferation,migration,and invasion,and to clarify its potential mechanism.Methods:The T98G cells at logarithmic growth phase were divided into control group and different concentrations(25,50,and 100 mg·L-1)of BBR groups.Cell wound healing assay was used to detect the migration rates of the cells in various groups;Transwell chamber assay was used to detect the invasion rates of the cells in various groups.The T98G cells at logarithmic growth phase were divided into control group and 100 mg·L-1 BBR group,and Mass spectrometry was used to detect the fatty acid contents in the cells in two groups.The T98G cells at logarithmic growth phase were divided into control group and different concentrations(50,100,and 150 mg·L-1)of BBR groups;Western blotting method was used to detect the expression levels of phosphatidylinositol 3-kinase(PI3K),phosphorylated PI3K(p-PI3K),protein kinase B(AKT),phosphorylated AKT(p-AKT),sterol regulatory element-binding protein 1(SREBP-1),and fatty acid synthase(FASN)in the cells in various groups.The expression of FASN was suppressed by gene silencing technology,and the T98G cells at logarithmic growth phase were divided into control group,shFASN1 group,and shFASN2 group.Western blotting method was used to detect the expression levels of FASN protein in the cells in various groups;clone formation assay was used to detect the clone formation of the cells in various groups;cell wound healing assay was used to detect the migration rates of the cells in various groups.Results:Compared with control group,the migration rates and invasion rates of the cells in different concentrations of BBR groups were decreased in a concentration-dependent manner(P<0.01),and the fatty acid content in the cells in 100 mg·L-1 BBR group was significantly decreased(P<0.01).Compared with control group,the expression levels of p-PI3K,p-AKT,SREBP-1,and FASN proteins in the cells in 150 mg·L-1 BBR group were significantly decreased(P<0.05 or P<0.01),and the expression level of SREBP-1 protein in the cells in 100 and 150 mg·L-1 BBR groups were significantly decreased(P<0.01).After suppression of FASN expression,compared with control group,the expression levels of FASN protein in the cells in shFASN1 and shFASN2 groups were significantly decreased(P<0.01),and the expression level of FASN protein in the cells in shFASN2 group was lower than that in shFASN1 group(P<0.05);compared with control group,the numbers of clone formation and migration rates of the cells in shFASN1 and shFASN2 groups were significantly decreased(P<0.01),and the migration rate of the cells in shFASN2 group was significantly lower than that in shFASN1 group(P<0.05).Conclusion:BBR interferes with fatty acid synthesis in the glioma T98G cells by reducing the expression of the PI3K/AKT/SREBP-1/FASN pathway related proteins,and decrease their migration and invasion capabilities.

7.
Article de Chinois | WPRIM (Pacifique Occidental) | ID: wpr-1026216

RÉSUMÉ

A GC-LSTM model is proposed based on the characteristics of global optimization of genetic algorithm.The model automatically and iteratively searches the optimal hyper-parameter configuration of the C-LSTM model through the genetic algorithm of a specific genetic strategy,and it is configured using the genetic iteration results and validated on the MIT-BIH arrhythmia database according to the classification criteria of the Association for the Advancement of Medical Instrumentation.The testing shows that the classification accuracy,sensitivity,accuracy and F1 value of GC-LSTM model are 99.37%,95.62%,95.17%and 95.39%,respectively,higher than those of the manually established model,and it is also advantageous over the existing mainstream methods.Experimental results demonstrate that the proposed method can achieve better classification performance while avoiding a large number of experimental parameters.

8.
Article de Chinois | WPRIM (Pacifique Occidental) | ID: wpr-1028773

RÉSUMÉ

AIM To explore the clinical effects of Bufei Huatan Dingchuan Decoction on patients with acute exacerbation of chronic obstructive pulmonary disease of Lung-Kidney Deficiency Pattern.METHODS One hundred and thirty-eight patients were randomly assigned into control group(69 cases)for 4-week intervention of conventional treatment,and observation group(69 cases)for 4-week intervention of both Bufei Huatan Dingchuan Decoction and conventional treatment.The changes in clinical effects,MMP-2,HIF-1α,TGF-β1,Gal-3,IL-6,pulmonary function indices(FVC,PEF,FEV1/FVC),6-minute walk distance,CAT score and TCM syndrome score were detected.RESULTS The observation group demonstrated higher total effective rate than the control group(P<0.05).After the treatment,the two groups displayed decreased MMP-2,HIF-1α,TGF-β1,IL-6,Gal-3,CAT score,TCM syndrome score(P<0.05),increased function indices(except for FVC)(P<0.05),and prolonged 6-minute walk distance(P<0.05),especially for the observation group(P<0.05).CONCLUSION For the patients of Lung-Kidney Deficiency Pattern,Bufei Huatan Dingchuan Decoction can alleviate inflammatory reactions,improve body hypoxia state,regulate lung functions,prevent airway tissue remodeling,promote disease recovery,and enhance clinical effects.

9.
Article de Chinois | WPRIM (Pacifique Occidental) | ID: wpr-1028815

RÉSUMÉ

Objective To compare the efficacy of TightRope loop plate and Endobutton plate in the treatment of acromioclavicular joint dislocation.Methods A retrospective analysis was conducted on 94 patients with acromioclavicular joint dislocation who were treated at this center from March 2021 to February 2023.They were divided into two groups based on different admission date.The Group E(n =47)received Endobutton plate treatment between March 2021 and February 2022,while the Group T(n =47)received TightRope loop plate treatment between March 2022 and February 2023.At the last follow-up,the perioperative indicators,Visual Analogue Scale(VAS),Constant-Murley shoulder joint function scores,and surgical complications were compared between the two groups.Results The surgical time,intraoperative bleeding,incision length,and VAS scores at 7 days after surgery in the Group T were shorter or lower than those in the Group E(P<0.05).There were no statistical differences in the incidence of perioperative nerve injury,internal fixation displacement,clavicle fracture,vascular injury,and infection between the two groups(P>0.05).The subjective and objective scores of Constant-Murley shoulder joint function in both groups at9 months after surgery showed significant improvement compared to preoperative scores(all P =0.000).There was no significant difference in the subjective and objective scores of Constant-Murley shoulder joint function between the two groups at 9 months after surgery(P>0.05).Conclusions The treatment of acromioclavicular joint dislocation with TightRope loop plate ot or Endobutton plate has a significant effect and can effectively improve shoulder joint function.Compared with Endobutton plate,use of TightRope loop plate has minor surgical trauma,less bleeding,and significantly reduced postoperative pain,being more conducive to early functional exercise for patients.

10.
Chinese Journal of Neurology ; (12): 80-84, 2024.
Article de Chinois | WPRIM (Pacifique Occidental) | ID: wpr-1029177

RÉSUMÉ

COVID-19 associated Guillain-Barré syndrome (GBS) caused by peripheral nerve damage after SARS-CoV-2 infection is one of the most common COVID-19 related nervous system inflammatory diseases, with high incidence of respiratory failure and mortality. Positive SARS-CoV-2 RNA in cerebrospinal fluid of COVID-19 associated GBS patients has been rarely reported. This paper reports 4 patients with COVID-19 associated GBS in China who developed neurological symptoms 4-15 days after fever and were confirmed SARS-CoV-2 infection. All patients presented with progressive weakness of both lower limbs, 3 patients with autonomic dysfunction such as defecation and urination disorders, and 1 patient with polycranial neuritis and Miller-Fisher syndrome such as bilateral facial palsy, dysphagia, diplopia and ataxia. Nerve conduction velocity and F wave were abnormal in 3 patients, and motor conduction pathway was abnormal in 1 patient. Anti-ganglioside antibodies were tested in 3 patients, and GD1a-IgG was positive in 1 patient. All 4 patients underwent metagenomic next-generation sequencing examination in blood and cerebrospinal fluid. SARS-CoV-2 RNA was positive in blood and cerebrospinal fluid of 3 patients, and SARS-CoV-2 RNA was positive in cerebrospinal fluid of 1 patient.

11.
Article de Chinois | WPRIM (Pacifique Occidental) | ID: wpr-1023857

RÉSUMÉ

AIM:To observe how total flavonoids of Pterocarya hupehensis Skan(PHSTF)affects the migra-tion and invasion of human rheumatoid fibroblast-like synoviocyte line MH7A.METHODS:The MH7A cells were divided into control group(without any treatment),low-,medium-and high-dose(6.25,12.5 and 25 mg/L,respectively)PHSTF groups,phosphatidylinositol 3-kinase(PI3K)inhibitor 740Y-P(10 μmol/L)group,and 740Y-P(10 μmol/L)+high-dose(25 mg/L)PHSTF group.The viability of the MH7A cells was determined by CCK-8 assay,while the migration and inva-sion were assessed by scratch and Transwell assays.The protein levels of matrix metalloproteinase-2(MMP-2),MMP-9,PI3K,p-PI3K,AKT and p-AKT were detected by Western blot.RESULTS:Compared with control group,the cell via-bility in PHSTF treatment groups was reduced(P<0.05),the cell wound healing area was significantly decreased(P<0.01),migratory and invasive cells in the lower chamber were significantly reduced(P<0.01),and the protein expres-sion of MMP-2 and MMP-9 and the ratios of p-PI3K/PI3K and pAKT/AKT were decreased(P<0.01).Compared with high-dose PHSTF group,the addition of PI3K/AKT pathway agonist 740Y-P significantly increased the migration and invasion ability of MH7A cells(P<0.01)and elevated the protein expression of MMP-2 and MMP-9 and the ratios of p-PI3K/PI3K and pAKT/AKT(P<0.01)under the treatment with PHSTF.CONCLUSION:Total flavonoids of Pterocarya hupehensis Skan could inhibit the migration and invasion of MH7A cells by regulating the PI3K/AKT signaling pathway.

12.
Article de Chinois | WPRIM (Pacifique Occidental) | ID: wpr-1023874

RÉSUMÉ

AIM:To investigate the impact of total flavonoids of Pterocarya hupehensis Skan(PHSTF)on the migration,invasion,and ferroptosis of non-small-cell lung cancer A549 cells.METHODS:The A549 cells were divided into control group,low-,medium-and high-dose(100,150 and 200 μg/mL)PHSTF groups,ferroptosis inhibitor liprox-statin-1(Lip-1)group,and high-dose PHSTF combined with Lip-1 group,each cultured in corresponding media.Cell via-bility was assessed using the CCK-8 assay,while cell migration and invasion abilities were determined through scratch and Transwell assays.Cell lipid peroxidation levels were measured using the glutathione(GSH)assay kit.RT-qPCR was em-ployed to assess the mRNA expression of solute carrier family 7 member 11(SLC7A11)and glutathione peroxidase 4(GPX4),while Western blot was utilized to examine the protein expression of SLC7A11,GPX4,Kelch-like epichlorohy-drin-associated protein-1(Keap-1),nuclear factor E2-related factor 2(Nrf2)and heme oxygenase-1(HO-1).RE-SULTS:Compared with control group,PHSTF significantly diminished the viability of A549 cells in a time-and dose-de-pendent manner(P<0.01),and the cell migration and invasion were also reduced(P<0.01),along with a significant de-crease in GSH level(P<0.01).Treatment with PHSTF inhibited the mRNA and protein expression levels of ferroptosis-re-lated proteins,including SLC7A11 and GPX4(P<0.01),suppressed the protein expression of Nrf2 and HO-1(P<0.01),and enhanced the expression of Keap-1(P<0.01).The Lip-1 partially restored the decrease in cell viability in-duced by PHSTF(P<0.01),significantly up-regulated the protein expression levels of SLC7A11,GPX4,Nrf2 and HO-1,and suppressed the protein expression of Keap-1(P<0.01).CONCLUSION:Total flavonoids of Pterocarya hupehen-sis Skan can inhibit the migration and invasion of non-small-cell lung cancer A549 cells,and induce the cell ferroptosis by regulating the Keap-1/Nrf2/HO-1 pathway.

13.
Article de Chinois | WPRIM (Pacifique Occidental) | ID: wpr-1024356

RÉSUMÉ

Objective To analyze the incidence and risk factors of hypothermia in elderly patients with malnutrition during proximal femoral nail antirotation(PFNA)internal fixation under general anesthesia.Methods A total of 139 elderly patients underwent PFNA internal fixation under general anesthesia were selected,and the nutritional status scores 1 day before surgery ranged from 0 to 11 points.Univariate and multivariate Logistic binary regression analysis was performed to analyze the related factors that may lead to intraoperative hypothermia.Results Among 139 elderly patients with preoperative nutritional scores of 0 to 11 points,79 cases(56.83%)developed intraoperative hypothermia.The results of univariate and multivariate Logistic binary regression analysis suggested that age≥75 years old,mini nutritional assessment short form(MNA-SF)nutritional score 0 to 7 points,BMI<18.5 kg/m2,duration of general anesthesia≥2 hours,intraoperative flushing fluid volume≥1 000 mL and intraoperative fluid volume≥1 000 mL were the risk factors for the occurrence of intraoperative hypothermia in elderly patients(OR>1,P<0.05).The use of warm blanket insulation was the protective factor against the occurrence of intraoperative hypothermia(OR<1,P<0.05).Conclusion The incidence of intraoperative hypothermia during PFNA internal fixation under general anesthesia in elderly patients with mainutrition before operation is high,and patients with poor nutritional status are more likely to develop intraoperative hypothermia.Patients with older age,poor nutritional status,lower BMI,longer duration of general anesthesia,and more intraoperative flushing fluid volume and intraoperative fluid volume are likely to lead to intraoperative hypothermia.The use of warm blanket can reduce the incidence of intraoperative hypothermia.

14.
Article de Chinois | WPRIM (Pacifique Occidental) | ID: wpr-1036491

RÉSUMÉ

Traumatic fractures and stress fractures are common orthopedic diseases, and there is great potential in researching bone turnover, repair, and promotion of fracture healing. Basic medical experiments often use animal models of long bone fractures in limbs to study the mechanisms of various interventions on fracture healing. Fracture healing is a complex process influenced by multiple factors and involves multiple molecules and pathways. Therefore, to explore the mechanisms more deeply, accelerate the translation of results, and improve the clinical efficacy, it is particularly important to choose the appropriate animal fracture modeling methods in experimental research. Based on this, this paper conducts a literature review of animal species and modeling methods commonly used for long bone fracture models in experimental research. It summarizes five methods: bone defect method, physical impact method, mechanical bending method, open osteotomy method, and drilling method. A side-by-side comparison of their advantages, disadvantages, and scope of application is made, aiming to provide suitable fracture models for studying the mechanisms of fracture healing interventions.

15.
Chinese Medical Ethics ; (6): 206-210, 2024.
Article de Chinois | WPRIM (Pacifique Occidental) | ID: wpr-1012877

RÉSUMÉ

In order to build a global community of health for all, it is necessary to deeply understand the influencing factors of cross-cultural communication between medical professionals and patients. Factors such as different health beliefs, cultural values and communication mediators influence cross-cultural communication between medical professionals and patients, and then affect the medical satisfaction and treatment compliance. Medical education should adopt the learning concept of constructivism, advocate maintaining a humble cultural attitude, incorporate more patient perspectives and adopt cross-cultural teaching mode to improve the cross-cultural communication competence of medical students and medical staff, so as to establish a relationship based on communication and understanding.

16.
Small ; 20(17): e2307955, 2024 Apr.
Article de Anglais | MEDLINE | ID: mdl-38148312

RÉSUMÉ

Unraveling the intricacies between oxygen dynamics and cellular processes in the tumor microenvironment (TME) hinges upon precise monitoring of intracellular and intratumoral oxygen levels, which holds paramount significance. The majority of these reported oxygen nanoprobes suffer compromised lifetime and quantum yield when exposed to the robust ROS activities prevalent in TME, limiting their prolonged in vitro usability. Herein, the ruthenium-embedded oxygen nano polymeric sensor (Ru-ONPS) is proposed for precise oxygen gradient monitoring within the cellular environment and TME. Ru-ONPS (≈64±7 nm) incorporates [Ru(dpp)3]Cl2 dye into F-127 and crosslinks it with urea and paraformaldehyde, ensuring a prolonged lifetime (5.4 µs), high quantum yield (66.65 ± 2.43% in N2 and 49.80 ± 3.14% in O2), superior photostability (>30 min), and excellent stability in diverse environmental conditions. Based on the Stern-Volmer plot, the Ru-ONPS shows complete linearity for a wide dynamic range (0-23 mg L-1), with a detection limit of 10 µg mL-1. Confocal imaging reveals Ru-ONPS cellular uptake and intratumoral distribution. After 72 h, HCT-8 cells show 5.20±1.03% oxygen levels, while NIH3T3 cells have 7.07±1.90%. Co-culture spheroids display declining oxygen levels of 17.90±0.88%, 10.90±0.88%, and 5.10±1.18%, at 48, 120, and 216 h, respectively. Ru-ONPS advances cellular oxygen measurement and facilitates hypoxia-dependent metastatic research and therapeutic target identification.


Sujet(s)
Oxygène , Polymères , Oxygène/métabolisme , Humains , Polymères/composition chimique , Microenvironnement tumoral , Lignée cellulaire tumorale , Animaux , Ruthénium/composition chimique , Souris , Techniques de biocapteur/méthodes , Espace intracellulaire/métabolisme
17.
Small ; : e2308676, 2023 Dec 10.
Article de Anglais | MEDLINE | ID: mdl-38072780

RÉSUMÉ

Highly emissive semiconductor nanocrystals, or so-called quantum dots (QDs) possess a variety of applications from displays and biology labeling, to quantum communication and modern security. Though ensembles of QDs have already shown very high photoluminescent quantum yields (PLQYs) and have been widely utilized in current optoelectronic products, QDs that exhibit high absorption cross-section, high emission intensity, and, most important, nonblinking behavior at single-dot level have long been desired and not yet realized at room temperature. In this work, infrared-emissive MAPbI3 -based halide perovskite QDs is demonstrated. These QDs not only show a ≈100% PLQY at the ensemble level but also, surprisingly, at the single-dot level, display an extra-large absorption cross-section up to 1.80 × 10-12 cm2 and non-blinking single photon emission with a high single photon purity of 95.3%, a unique property that is extremely rare among all types of quantum emitters operated at room temperature. An in-depth analysis indicates that neither trion formation nor band-edge carrier trapping is observed in MAPbI3 QDs, resulting in the suppression of intensity blinking and lifetime blinking. Fluence-dependent transient absorption measurements reveal that the coexistence of non-blinking behavior and high single photon purity in these perovskite QDs results from a significant repulsive exciton-exciton interaction, which suppresses the formation of biexciton, and thus greatly reduces photocharging. The robustness of these QDs is confirmed by their excellent stability under continuous 1 h electron irradiation in high-resolution transmission electron microscope inspection. It is believed that these results mark an important milestone in realizing nonblinking single photon emission in semiconductor QDs.

18.
ACS Nano ; 17(24): 25552-25564, 2023 Dec 26.
Article de Anglais | MEDLINE | ID: mdl-38096149

RÉSUMÉ

Photomemristors have been regarded as one of the most promising candidates for next-generation hardware-based neuromorphic computing due to their potentials of fast data transmission and low power consumption. However, intriguingly, so far, photomemristors seldom display truly nonvolatile memory characteristics with high light sensitivity. Herein, we demonstrate ultrasensitive photomemristors utilizing two-dimensional (2D) Ruddlesden-Popper (RP) perovskites with a highly polar donor-acceptor-type push-pull organic cation, 4-(5-(2-aminoethyl)thiophen-2-yl)benzonitrile+ (EATPCN+), as charge-trapping layers. High linearity and almost zero-decay retention are observed in (EATPCN)2PbI4 devices, which are very distinct from that of the traditional 2D RP perovskite devices consisting of nonpolar organic cations, such as phenethylamine+ (PEA+) and octylamine+ (OA+), and traditional 3D perovskite devices consisting of methylamine+ (MA+). The 2-fold advantages, including desirable spatial crystal arrangement and engineered energetic band alignment, clarify the mechanism of superior performance in (EATPCN)2PbI4 devices. The optimized (EATPCN)2PbI4 photomemristor also shows a memory window of 87.9 V and an on/off ratio of 106 with a retention time of at least 2.4 × 105 s and remains unchanged after >105 writing-reading-erasing-reading endurance cycles. Very low energy consumptions of 1.12 and 6 fJ for both light stimulation and the reading process of each status update are also demonstrated. The extremely low power consumption and high photoresponsivity were simultaneously achieved. The high photosensitivity surpasses that of a state-of-the-art commercial pulse energy meter by several orders of magnitude. With their outstanding linearity and retention, rabbit images have been rebuilt by (EATPCN)2PbI4 photomemristors, which truthfully render the image without fading over time. Finally, by utilizing the powerful ∼8 bits of nonvolatile potentiation and depression levels of (EATPCN)2PbI4 photomemristors, the accuracies of the recognition tasks of CIFAR-10 image classification and MNIST handwritten digit classification have reached 89% and 94.8%, respectively. This study represents the first report of utilizing a functional donor-acceptor type of organic cation in 2D RP perovskites for high-performance photomemristors with characteristics that are not found in current halide perovskites.

19.
Nanomaterials (Basel) ; 13(22)2023 Nov 15.
Article de Anglais | MEDLINE | ID: mdl-37999303

RÉSUMÉ

Current study provides a novel strategy to synthesize the nano-sized MnO nanoparticles from the quick, ascendable, sol-gel synthesis strategy. The MnO nanoparticles are supported on nitrogen-doped carbon derived from the cheap sustainable source. The resulting MnO/N-doped carbon catalysts developed in this study are systematically evaluated via several physicochemical and electrochemical characterizations. The physicochemical characterizations confirms that the crystalline MnO nanoparticles are successfully synthesized and are supported on N-doped carbons, ascertained from the X-ray diffraction and transmission electron microscopic studies. In addition, the developed MnO/N-doped carbon catalyst was also found to have adequate surface area and porosity, similar to the traditional Pt/C catalyst. Detailed investigations on the effect of the nitrogen precursor, heat treatment temperature, and N-doped carbon support on the ORR activity is established in 0.1 M of HClO4. It was found that the MnO/N-doped carbon catalysts showed enhanced ORR activity with a half-wave potential of 0.69 V vs. RHE, with nearly four electron transfers and excellent stability with just a loss of 10 mV after 20,000 potential cycles. When analyzed as an ORR catalyst in dual-chamber microbial fuel cells (DCMFC) with Nafion 117 membrane as the electrolyte, the MnO/N-doped carbon catalyst exhibited a volumetric power density of ~45 mW m2 and a 60% degradation of organic matter in 30 days of continuous operation.

20.
ACS Appl Mater Interfaces ; 15(37): 44033-44042, 2023 Sep 20.
Article de Anglais | MEDLINE | ID: mdl-37694918

RÉSUMÉ

Three organic conjugated small molecules, DTA-DTPZ, Cz-DTPZ, and DTA-me-DTPZ comprising an antiaromatic 5,10-ditolylphenazine (DTPZ) core and electron-donating peripheral substituents with high HOMOs (-4.2 to -4.7 eV) and multiple reversible oxidative potentials are reported. The corresponding films sandwiched between two electrodes show unipolar and switchable hysteresis current-voltage (I-V) characteristics upon voltage sweeping, revealing the prominent features of nonvolatile memristor behaviors. The numerical simulation of the I-V curves suggests that the carriers generated by the oxidized molecules lead to the increment of conductance. However, the accumulated carriers tend to deteriorate the device endurance. The electroactive sites are fully blocked in the dimethylated molecule DTA-me-DTPZ, preventing the irreversible electrochemical reaction, thereby boosting the endurance of the memristor device over 300 cycles. Despite the considerable improvement in endurance, the decrement of on/off ratio from 105 to 101 after 250 cycles suggests that the excessive charge carriers (radical cations) remains a problem. Thus, a new strategy of doping an electron-deficient material, CN-T2T, into the unipolar active layer was introduced to further improve the device stability. The device containing DTA-me-DTPZ:CNT2T (1:1) blend as the active layer retained the endurance and on/off ratio (∼104) upon sweeping 300 cycles. The molecular designs and doping strategy demonstrate effective approaches toward more stable metal-free organic conjugated small-molecule memristors.

SÉLECTION CITATIONS
DÉTAIL DE RECHERCHE