Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 132
Filtrar
1.
Nature ; 616(7957): 482-487, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-37076728

RESUMEN

Partitioning of americium from lanthanides (Ln) present in used nuclear fuel plays a key role in the sustainable development of nuclear energy1-3. This task is extremely challenging because thermodynamically stable Am(III) and Ln(III) ions have nearly identical ionic radii and coordination chemistry. Oxidization of Am(III) to Am(VI) produces AmO22+ ions distinct with Ln(III) ions, which has the potential to facilitate separations in principle. However, the rapid reduction of Am(VI) back to Am(III) by radiolysis products and organic reagents required for the traditional separation protocols including solvent and solid extractions hampers practical redox-based separations. Herein, we report a nanoscale polyoxometalate (POM) cluster with a vacancy site compatible with the selective coordination of hexavalent actinides (238U, 237Np, 242Pu and 243Am) over trivalent lanthanides in nitric acid media. To our knowledge, this cluster is the most stable Am(VI) species in aqueous media observed so far. Ultrafiltration-based separation of nanoscale Am(VI)-POM clusters from hydrated lanthanide ions by commercially available, fine-pored membranes enables the development of a once-through americium/lanthanide separation strategy that is highly efficient and rapid, does not involve any organic components and requires minimal energy input.

2.
J Am Chem Soc ; 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38489242

RESUMEN

We present the first example of an 99TcO4- anion entrapped within the cavity of a silver cluster, revealing an unprecedented photoinduced charge transfer phenomenon. [Ag24(C≡CtBu)20(99TcO4)]·(BF4)3 (denoted as 99TcO4-@Ag24) was successfully synthesized and structurally characterized. Single-crystal X-ray diffraction and Raman spectroscopy reveal that the tetrahedral structure of the 99TcO4- anion sustains significant symmetry breaking with weakened Tc-O bond strength under confinement within the Ag24(C≡CtBu)204+ cluster. Notably, 99TcO4-@Ag24 exhibits a broadband electronic absorption spectrum in the visible region, which was absent for the other 99TcO4--containing compounds. Density functional theory calculations elucidate that host-guest electrostatic interactions result in an electron polarization effect between the 99TcO4- anion core and the Ag24 cationic shell. The emergence of an absorption band in 99TcO4-@Ag24 is rationalized by intermolecular charge transfer from the Ag24 electronic states to the lowest unoccupied molecular orbitals of 99TcO4- instead of the intramolecular electron transition observed in other 99TcO4--containing compounds.

3.
J Am Chem Soc ; 146(10): 6697-6705, 2024 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-38419157

RESUMEN

Synthesizing large metal-organic framework (MOF) single crystals has garnered significant research interest, although it is hindered by the fast nucleation kinetics that gives rise to numerous small nuclei. Given the different chemical origins inherent in various types of MOFs, the development of a general approach to enhancing their crystal sizes presents a formidable challenge. Here, we propose a simple isotopic substitution strategy to promote size growth in MOFs by inhibiting nucleation, resulting in a substantial increase in the crystal volume ranging from 1.7- to 165-fold. Impressively, the crystals prepared under optimized conditions by normal approaches can be further enlarged by the isotope effect, yielding the largest MOF single crystal (2.9 cm × 0.48 cm × 0.23 cm) among the one-pot synthesis method. Detailed in situ characterizations reveal that the isotope effect can retard crystallization kinetics, establish a higher nucleation energy barrier, and consequently generate fewer nuclei that eventually grow larger. Compared with the smaller crystals, the isotope effect-enlarged crystal shows 33% improvement in the X-ray dose rate detection limit. This work enriches the understanding of the isotope effect on regulating the crystallization process and provides inspiration for exploring potential applications of large MOF single crystals.

4.
Biochem Biophys Res Commun ; 694: 149409, 2024 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-38141558

RESUMEN

The NLRP3 inflammasome has gained significant attention due to its participation in diverse cellular processes. Nevertheless, the detailed framework of the canonical NLRP3 inflammasome assembly still remains unrevealed. This study aims to elucidate the transcriptomic landscape of the various stages involved in the canonical activation of the NLRP3 inflammasome in BMDMs by integrating RNA-seq, bioinformatics, and molecular dynamics analyses. The model for the canonical activation of the NLRP3 inflammasome was confirmed through morphological observations, functional assessments (ELISA and LDH), and protein detection (western blot). Subsequently, cells were subjected to RNA sequencing following three groups: control, priming (LPS 500 ng/ml, 4 h), and activation (LPS 500 ng/ml, 4 h; ATP 5 mM, 1 h). A total of 9116 differentially expressed genes (DEGs) were identified, which exerted regulatory effects on various pathways, including cell metabolism, ion fluxes, post-translational modifications, and organelles. Subsequently, six hub genes (Sirt3, Stat3, Syk, Trpm2, Tspo, and Txnip) were identified via integrating literature review and database screening. Finally, the three-dimensional structures of these six hub proteins were obtained using the MD-optimized RoseTTAFold and Gromacs simulations (at least 200 ns). In summary, our research offers novel insights into the transcriptomic-level understanding of the assembly of the canonical NLRP3 inflammasome.


Asunto(s)
Inflamasomas , Proteína con Dominio Pirina 3 de la Familia NLR , Inflamasomas/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/genética , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Lipopolisacáridos/metabolismo , Macrófagos/metabolismo , Perfilación de la Expresión Génica , Interleucina-1beta/metabolismo
5.
Inorg Chem ; 63(21): 9706-9710, 2024 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-38747511

RESUMEN

Herein, we detail the synthesis, structure, and photoconductivity of the uranyl dithiophosphinate single crystal UO2[S2P(C6H5)2]2(CH3OH)·CH3OH (denoted as U-DPDPP). The formation of bonds between uranyl ions and sulfur-based ligands endows U-DPDPP with a distinct electronic absorption property with a broadband spectrum spanning from 250 to 550 nm, giving rise to a unique semiconductive property. Under X-ray illumination, U-DPDPP displays a distinctive photoconductivity response, with a charge carrier mobility lifetime (µτ) of 2.78 × 10-4 cm2·V-1 achieved, which contradicts the electronic-silence behavior of uranyl nitrate crystal.

6.
Inorg Chem ; 63(8): 3642-3647, 2024 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-38346447

RESUMEN

Two X-ray scintillators based on organic-inorganic hybrids were constructed by judiciously incorporating lanthanide cations and organic ligands within a single material. The obtained Eu-pba and Tb-pba not only feature excellent radiation, hydrolytic, and thermal stabilities but also exhibit a linear response to the X-ray dose rate with detection limits of 4.92 and 3.17 µGy s-1, respectively. We further present a flexible scintillator film fabricated by embedding Tb-pba in a polydimethylsiloxane (PDMS) polymer. Their incorporation enables X-ray imaging with a spatial resolution of approximately 10 lp mm-1. These results emphasize the potential of lanthanide organic-inorganic hybrids to achieve outstanding performance in X-ray scintillation and imaging.

7.
Graefes Arch Clin Exp Ophthalmol ; 262(3): 769-776, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37878036

RESUMEN

PURPOSE: To report the characteristics and the visual and anatomical outcomes of secondary macular holes (SMHs) diagnosed after rhegmatogenous retinal detachment (RRD) repair and their associated factors. METHODS: Retrospective, interventional case series. All consecutive patients who were diagnosed with SMH after RRD repair at Beijing Tongren eye center from January 2016 to April 2021 were included. Patients who had their primary RRD repair in other hospitals and were referred to our center after diagnosis of SMH were also included. The minimum follow-up time after RRD repair was 6 months. RESULTS: 37 SMHs were diagnosed within a series of 5696 RRDs. Including 24 eyes referred from other hospitals after the diagnosis of SMH, 61 eyes were included. The type of primary RRD repair surgery included 22/61 (36%) eyes with scleral buckling procedure (SBP) and 39/61 (64%) eyes with pars plana vitrectomy (PPV). 21/61 (34%) eyes had recurrent RD. The median time to SMH diagnosis was 150 days (range, 7 ~ 4380 days). Macular hole (MH) closure was achieved in 77% eyes. Visual acuity (VA) improvement of at least 2 lines of Snellen's visual acuity was observed in 51% eyes. Final MH closure status was associated with preoperative MH diameter (for every 50 µm increment) (P = 0.046, OR = 0.875, 95%CI: 0.767 ~ 0.998). VA improvement was associated with final MH closure status (P = 0.009, OR = 8.742, 95%CI: 1.711 ~ 44.672). Final VA (logMAR) was associated with recurrent RD (P < 0.001, B = 0.663, 95%CI: 0.390 ~ 0.935), preoperative MH diameter (P = 0.001, B = 0.038, 95%CI: 0.017 ~ 0.058), VA at the time of SMH diagnosis (P < 0.001, B = 0.783, 95%CI: 0.557 ~ 1.009) and final MH closure status (P = 0.024, B = -0.345, 95%CI: -0.644 ~ -0.046). For patients without recurrent RD, VA improvement and final VA was associated with final MH closure status (P = 0.016 and P < 0.001, respectively), while for patients with recurrent RD, VA improvement or final VA did not associate with final MH closure status (P > 0.05). CONCLUSION: For SMH diagnosed after RRD repair, final MH closure status was associated with preoperative MH diameter. Recurrent RD, larger preoperative MH diameter, worse VA at the time of SMH diagnosis and failed MH closure are predictive factors for worse final VA. Visual outcome is associated with final MH closure status in patients without recurrent RD, but not as so in patients with recurrent RD.


Asunto(s)
Desprendimiento de Retina , Perforaciones de la Retina , Humanos , Perforaciones de la Retina/diagnóstico , Perforaciones de la Retina/cirugía , Perforaciones de la Retina/complicaciones , Desprendimiento de Retina/diagnóstico , Desprendimiento de Retina/cirugía , Estudios Retrospectivos , Curvatura de la Esclerótica/métodos , Retina
8.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 41(3): 527-534, 2024 Jun 25.
Artículo en Zh | MEDLINE | ID: mdl-38932539

RESUMEN

There are some problems in positron emission tomography/ computed tomography (PET/CT) lung images, such as little information of feature pixels in lesion regions, complex and diverse shapes, and blurred boundaries between lesions and surrounding tissues, which lead to inadequate extraction of tumor lesion features by the model. To solve the above problems, this paper proposes a dense interactive feature fusion Mask RCNN (DIF-Mask RCNN) model. Firstly, a feature extraction network with cross-scale backbone and auxiliary structures was designed to extract the features of lesions at different scales. Then, a dense interactive feature enhancement network was designed to enhance the lesion detail information in the deep feature map by interactively fusing the shallowest lesion features with neighboring features and current features in the form of dense connections. Finally, a dense interactive feature fusion feature pyramid network (FPN) network was constructed, and the shallow information was added to the deep features one by one in the bottom-up path with dense connections to further enhance the model's perception of weak features in the lesion region. The ablation and comparison experiments were conducted on the clinical PET/CT lung image dataset. The results showed that the APdet, APseg, APdet_s and APseg_s indexes of the proposed model were 67.16%, 68.12%, 34.97% and 37.68%, respectively. Compared with Mask RCNN (ResNet50), APdet and APseg indexes increased by 7.11% and 5.14%, respectively. DIF-Mask RCNN model can effectively detect and segment tumor lesions. It provides important reference value and evaluation basis for computer-aided diagnosis of lung cancer.


Asunto(s)
Neoplasias Pulmonares , Tomografía Computarizada por Tomografía de Emisión de Positrones , Humanos , Neoplasias Pulmonares/diagnóstico por imagen , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Pulmón/diagnóstico por imagen , Algoritmos , Procesamiento de Imagen Asistido por Computador/métodos , Redes Neurales de la Computación
9.
J Am Chem Soc ; 145(27): 14679-14685, 2023 07 12.
Artículo en Inglés | MEDLINE | ID: mdl-37366004

RESUMEN

225Ac is considered as one of the most promising radioisotopes for alpha-therapy because its emitted high-energy α-particles can efficiently damage tumor cells. However, it also represents a significant threat to healthy tissues owing to extremely high radiotoxicity if targeted therapy fails. This calls for a pressing requirement of monitoring the biodistribution of 225Ac in vivo during the treatment of tumors. However, the lack of imageable photons or positrons from therapeutic doses of 225Ac makes this task currently quite challenging. We report here a nanoscale luminescent europium-organic framework (EuMOF) that allows for fast, simple, and efficient labeling of 225Ac in its crystal structure with sufficient 225Ac-retention stability based on similar coordination behaviors between Ac3+ and Eu3+. After labeling, the short distance between 225Ac and Eu3+ in the structure leads to exceedingly efficient energy transduction from225Ac-emitted α-particles to surrounding Eu3+ ions, which emits red luminescence through a scintillation process and produces sufficient photons for clearcut imaging. The in vivo intensity distribution of radioluminescence signal originating from the 225Ac-labeled EuMOF is consistent with the dose of 225Ac dispersed among the various organs determined by the radioanalytical measurement ex vivo, certifying the feasibility of in vivo directly monitoring 225Ac using optical imaging for the first time. In addition, 225Ac-labeled EuMOF displays notable efficiency in treating the tumor. These results provide a general design principle for fabricating 225Ac-labeled radiopharmaceuticals with imaging photons and propose a simple way to in vivo track radionuclides with no imaging photons, including but not limited to 225Ac.


Asunto(s)
Estructuras Metalorgánicas , Neoplasias , Humanos , Distribución Tisular , Radioisótopos , Radiofármacos , Neoplasias/tratamiento farmacológico
10.
J Am Chem Soc ; 145(24): 13161-13168, 2023 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-37287236

RESUMEN

Lanthanide organic frameworks (Ln-MOFs) have attracted increasing research enthusiasm as photoluminescent materials. However, limited luminescence efficiency stemming from restricted energy transfer efficiency from the organic linker to the metal center hinders their applications. Herein, a uranyl sensitization approach was proposed to boost the luminescence efficiency of Ln-MOFs in a distinct heterobimetallic uranyl-europium organic framework. The record-breaking photoluminescence quantum yield (PLQY, 92.68%) among all reported Eu-MOFs was determined to benefit from nearly 100% energy transfer efficiency between UO22+ and Eu3+. Time-dependent density functional theory and ab initio wave-function theory calculations confirmed the overlap of excited state levels between UO22+ and Eu3+, which is responsible for the efficient energy transfer process. Coupled with intrinsically strong stopping power toward X-ray of the uranium center, SCU-UEu-2 features an ultralow detection limit of 1.243 µGyair/s, outperforming the commercial scintillator LYSO (13.257 µGyair/s) and satisfying the requirement of X-ray diagnosis (below 5.5 µGyair/s) in full.

11.
BMC Plant Biol ; 23(1): 455, 2023 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-37770835

RESUMEN

BACKGROUND: Salt stress is one of the key factors limiting rice production. Alginate oligosaccharides (AOS) enhance plant stress resistance. However, the molecular mechanism underlying salt tolerance in rice induced by AOS remains unclear. FL478, which is a salt-tolerant indica recombinant inbred line and IR29, a salt-sensitive rice cultivar, were used to comprehensively analyze the effects of AOS sprayed on leaves in terms of transcriptomic and metabolite profiles of rice seedlings under salt stress. RESULTS: In this experiment, exogenous application of AOS increased SOD, CAT and APX activities, as well as GSH and ASA levels to reduce the damage to leaf membrane, increased rice stem diameter, the number of root tips, aboveground and subterranean biomass, and improved rice salt tolerance. Comparative transcriptomic analyses showed that the regulation of AOS combined with salt treatment induced the differential expression of 305 and 1030 genes in FL478 and IR29. The expressed genes enriched in KEGG pathway analysis were associated with antioxidant levels, photosynthesis, cell wall synthesis, and signal transduction. The genes associated with light-trapping proteins and RLCK receptor cytoplasmic kinases, including CBA, LHCB, and Lhcp genes, were fregulated in response to salt stress. Treatment with AOS combined with salt induced the differential expression of 22 and 50 metabolites in FL478 and IR29. These metabolites were mainly related to the metabolism of amino and nucleotide sugars, tryptophan, histidine, and ß -alanine. The abundance of metabolites associated with antioxidant activity, such as 6-hydroxymelatonin, wedelolactone and L-histidine increased significantly. Combined transcriptomic and metabolomic analyses revealed that dehydroascorbic acid in the glutathione and ascorbic acid cycles plays a vital role in salt tolerance mediated by AOS. CONCLUSION: AOS activate signal transduction, regulate photosynthesis, cell wall formation, and multiple antioxidant pathways in response to salt stress. This study provides a molecular basis for the alleviation of salt stress-induced damage by AOS in rice.


Asunto(s)
Oryza , Transcriptoma , Plantones/genética , Plantones/metabolismo , Antioxidantes/metabolismo , Oryza/metabolismo , Estrés Salino/genética , Glutatión/metabolismo , Oligosacáridos/metabolismo , Oligosacáridos/farmacología
12.
Inorg Chem ; 62(39): 15834-15841, 2023 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-37724987

RESUMEN

A highly sensitive detection of ultraviolet (UV) radiation is required in a broad range of scientific research, chemical industries, and health-related applications. Traditional UV photodetectors fabricated by direct wide-band-gap inorganic semiconductors often suffer from several disadvantages such as complicated manufacturing procedures, requiring multiple operations and high-cost instruments to obtain a readout. Searching for new materials or simple strategies to develop UV dosimeters for quantitative, accurate, and on-site detection of UV radiation dose is still highly desirable. Herein, a photochromic uranyl-based coordination polymer [(UO2)(PBPCA)·DMF]·DMF (PBPCA = pyridine-3,5-bis(phenyl-4-carboxylate), DMF = N,N'-dimethylformamide, denoted as SXU-1) with highly radiolytic and chemical stabilities was successfully synthesized via the solvothermal method at 100 °C. Surprisingly, the fresh samples of SXU-1 underwent an ultra-fast UV-induced (365 nm, 2 mW) color variation from yellow to orange in less than 1 s, and then the color changed further from orange to brick red after the subsequent irradiation, inspiring us to develop a colorimetric dosimeter based on red-green-blue (RGB) parameters. The mechanism of radical-induced photochromism was intensively investigated by UV-vis absorption spectra, EPR analysis, and SC-XRD data. Furthermore, SXU-1 was incorporated into an optoelectronic device to fabricate a novel dosimeter for convenient, quantitative, and on-site detection of UV radiation dose.

13.
Angew Chem Int Ed Engl ; 62(38): e202304638, 2023 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-37258939

RESUMEN

Halide perovskites (HPs) recently have emerged as one class of competitive scintillators for X-ray detection and imaging owing to its high quantum efficiency, short decay time, superior X-ray absorption capacity, low cost, and ease of crystal growth. The tunable structure and versatile chemical compositions of halide perovskites provide distinguishable advantages over traditional inorganic scintillators for optimizing scintillation performance. Since the first observation of the scintillation phenomenon in HPs, substantial efforts have been devoted to expanding the inventory of HP scintillators and regulating material properties. Understanding the relationship between the structure and scintillation properties of HP scintillators is essential for developing materials with improved X-ray detection and imaging capacities. This review summarizes strategies for improving the light yield of HP scintillators and provides a roadmap for improving the X-ray imaging performance. Additionally, methods for controlling the light propagation direction in HP scintillators are highlighted for improving X-ray imaging resolution. Finally, we highlight the current challenge in HP scintillators and provide a perspective on the future development of this emerging scintillator.

14.
Angew Chem Int Ed Engl ; 62(33): e202306465, 2023 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-37249485

RESUMEN

The development of high-performance X-ray detectors requires scintillators with fast decay time, high light yield, stability, and X-ray absorption capacity, which are difficult to achieve in a single material. Here, we present the first example of a lanthanide chalcogenide of LaCsSiS4 : 1 % Ce3+ that simultaneously integrates multiple desirable properties for an ideal scintillator. LaCsSiS4 : 1 % Ce3+ demonstrates a remarkably low detection limit of 43.13 nGyair s-1 and a high photoluminescence quantum yield of 98.24 %, resulting in a high light yield of 50480±1441 photons/MeV. Notably, LaCsSiS4 : 1 % Ce3+ exhibits a fast decay time of only 29.35±0.16 ns, making it one of the fastest scintillators among all lanthanide-based inorganic scintillators. Furthermore, this material shows robust radiation and moisture resistance, endowing it with suitability for chemical processing under solution conditions. To demonstrate the X-ray imaging capacity of LaCsSiS4 : 1 % Ce3+ , we fabricated a flexible X-ray detector that achieved a high spatial resolution of 8.2 lp mm-1 . This work highlights the potential of lanthanide chalcogenide as a promising candidate for high-performance scintillators.

15.
J Cell Mol Med ; 26(10): 2895-2907, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35373434

RESUMEN

Pyroptosis is associated with various cardiovascular diseases. Increasing evidence suggests that long noncoding RNAs (lncRNAs) have been implicated in gene regulation, but how lncRNAs participate in the regulation of pyroptosis in the heart remains largely unknown. In this study, we aimed to explore the antipyroptotic effects of lncRNA FGF9-associated factor (FAF) in acute myocardial infarction (AMI). The expression patterns of lncRNA FAF, miR-185-5p and P21 activated kinase 2 (PAK2) were detected in hypoxia/ischaemia-induced cardiomyocytes. Hoechst 33342/PI staining, lactate dehydrogenase (LDH) release assay, immunofluorescence and Western blotting were conducted to assay cell pyroptosis. The interaction between lncRNA FAF, miR-185-5p and PAK2 was verified by bioinformatics analysis, small RNA sequencing luciferase reporter assay and qRT-PCR. The expression of LncRNA FAF was downregulated in hypoxic cardiomyocytes and myocardial tissues. Overexpression of lncRNA FAF could attenuate cardiomyocyte pyroptosis, improve cell viability and reduce infarct size during the procession of AMI. Moreover, lncRNA FAF was confirmed as a sponge of miR-185-5p and promoted PAK2 expression in cardiomyocytes. Collectively, our findings reveal a novel lncRNA FAF/miR-185-5p/PAK2 axis as a crucial regulator in cardiomyocyte pyroptosis, which might be a potential therapeutic target of AMI.


Asunto(s)
MicroARNs , Infarto del Miocardio , Miocitos Cardíacos , ARN Largo no Codificante , Quinasas p21 Activadas , Apoptosis , Humanos , Hipoxia/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Infarto del Miocardio/genética , Infarto del Miocardio/metabolismo , Miocitos Cardíacos/metabolismo , Piroptosis/genética , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , Quinasas p21 Activadas/genética , Quinasas p21 Activadas/metabolismo
16.
J Am Chem Soc ; 144(5): 2189-2196, 2022 02 09.
Artículo en Inglés | MEDLINE | ID: mdl-35073062

RESUMEN

Exciton behaviors including exciton formation and dissociation dynamics play an essential role in the optoelectronic performance of semiconductive materials but remain unexplored in semiconductive metal-organic frameworks (MOFs). Herein, we reveal that the exciton behaviors in semiconductive MOFs can be regulated by framework-guest interactions, a feature often not achievable in traditional inorganic or organic semiconductors. Incorporation of the electron-deficient molecule within the pores of a terbium-based semiconductive MOF (Tb2L2·4H2O·6DMF, L = TATAB3-, 4,4',4″-s-triazine-1,3,5-triyltri-p-aminobenzoate, DMF = N,N-dimethylformamide) results in efficient energy transfer from the MOF skeleton to molecular acceptors, with a yield of up to 77.4%. This interaction facilitates distinctive exciton type conversion, giving rise to modified conductivity and photoelectric performance. We further fabricated a MOF-based X-ray detection device to demonstrate how the new architecture bolsters the optoelectronic efficiency, which outperforms the properties of parent semiconductive MOFs, with more than 60 times and 40 times enhancement of the photocurrent on-off ratio and detection sensitivity, respectively. With judiciously optimized exciton behaviors, the detection device exhibits a high sensitivity of 51.9 µC Gyair-1 cm-2 and records a charge carrier mobility-lifetime product of 1.12 × 10-3 cm2 V-1 among MOF-based X-ray detectors, which are competitive with values for commercially available detectors. These findings demonstrate a rational synthetic approach to designing exciton arrangements to improve the optoelectronic efficiency of semiconductive MOFs.

17.
Inorg Chem ; 61(34): 13256-13260, 2022 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-35969238

RESUMEN

Hybrid metal halide perovskites are extensively synthesized using p- and d-elements. However, the properties of hybrid halide perovskites involving 5f-elements are still elusive. Herein, we first report the semiconductive property of a uranium-bearing hybrid halide perovskite, [N(C2H5)4]2UCl6 (EAUCl). Single crystal X-ray crystallography demonstrates that EAUCl adopts a zero-dimensional molecular structure consisting of isolated [UCl6]2- anions and organic cations. The intrinsically semiconductive property endows EAUCl with obvious charge transport and photoconductivity, with a high carrier mobility lifetime (µτ) product of 9.91 × 10-4 cm2/V and a photocurrent on-off ratio of 380 under X-ray excitation. Theoretical calculations corroborate that the U 5f orbitals are involved in electron transitions and the formation of band structure.

18.
Inorg Chem ; 61(11): 4561-4565, 2022 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-35261233

RESUMEN

Here, we report a series of two-dimensional lanthanide metal-organic frameworks Ln-DBTPA (where DBTPA = 2,5-dibromoterephthalic acid and Ln = Tb (1), Eu (2), or Gd (3)) showing a unique turn-up responsiveness toward ultraviolet (UV) radiation. The luminescence enhancement was derived from the accumulated radicals that can promote the intersystem crossing process. The compound 1 shows an ultralow detection limit of 9.1 × 10-9 J toward UV radiation, representing a new type of luminescent UV detectors.


Asunto(s)
Elementos de la Serie de los Lantanoides , Estructuras Metalorgánicas , Luminiscencia , Rayos Ultravioleta
19.
Entropy (Basel) ; 24(7)2022 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-35885133

RESUMEN

Quantum key distribution (QKD) can provide point-to-point information-theoretic secure key services for two connected users. In fact, the development of QKD networks needs more focus from the scientific community in order to broaden the service scale of QKD technology to deliver end-to-end secure key services. Of course, some recent efforts have been made to develop secure communication protocols based on QKD. However, due to the limited key generation capability of QKD devices, high quantum secure key utilization is the major concern for QKD networks. Since traditional routing techniques do not account for the state of quantum secure keys on links, applying them in QKD networks directly will result in underutilization of quantum secure keys. Therefore, an efficient routing protocol for QKD networks, especially for large-scale QKD networks, is desperately needed. In this study, an efficient routing protocol based on optimized link-state routing, namely QOLSR, is proposed for QKD networks. QOLSR considerably improves quantum key utilization in QKD networks through link-state awareness and path optimization. Simulation results demonstrate the validity and efficiency of the proposed QOLSR routing protocol. Most importantly, with the growth of communication traffic, the benefit becomes even more apparent.

20.
Angew Chem Int Ed Engl ; 61(37): e202208440, 2022 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-35859274

RESUMEN

Scintillators display radioluminescent properties when irradiated by high-energy photons and therefore play an essential role in radiation detection. The current inventory of scintillators is overwhelmingly represented by achiral structures, where the radioluminescence propagates isotropically after generation. Herein, we demonstrate that chiral perovskites of (R-3AP)PbBr3 Cl⋅H2 O (R-3APP) and (S-3AP)PbBr3 Cl⋅H2 O (S-3APP) emerge as a new type of scintillator displaying a distinct property of circularly polarized radioluminescence (CPRL). A high quantum yield of 27.6 %, high luminescence dissymmetric factors (glum ) of 4×10-2 , and high X-ray absorption coefficients were observed for these compounds. As proof of concept, we fabricated a polarized scintillator pair by assembling chiral scintillator crystals, which provides a new strategy to attenuate optical crosstalk between the scintillators by precisely controlling the radioluminescence propagation and improves the X-ray imaging quality at the boundary region.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA