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OBJECTIVES: To identify frailty trajectories and examine its association with allostatic load (AL) and mediating effect of physical activity (PA). METHODS: This study included 8,082 adults from the English Longitudinal Study of Aging over Waves 4-9. AL was calculated by 14 biological indicators, and a 53-item frailty index was used to evaluate frailty. Frailty trajectories were classified by group-based trajectory modeling, and the mediated effect of PA was tested by causal mediation analysis. RESULTS: Four frailty trajectories were identified: "Robustness" (n = 4,437, 54.9%), "Incident prefrailty" (n = 2,061, 25.5%), "Prefrailty to frailty" (n = 1,136, 14.1%), and "Frailty to severe frailty" (n = 448, 5.5%). High baseline AL was associated with increased odds of "Incident prefrailty," "Prefrailty to frailty," and "Frailty to severe frailty" trajectories. PA demonstrated significant mediated effects in aforementioned associations. CONCLUSIONS: AL is significantly associated with the onset and progression of frailty, and such associations are partially mediated by PA.
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Alostase , Fragilidade , Idoso , Humanos , Estudos Longitudinais , Idoso Fragilizado , Exercício FísicoRESUMO
A magnetic nitrogen-doped sludge-based biochar (NAlSB-Fe-Si) was prepared based on waterworks sludge for raw material and dicyandiamide for nitrogen source to adsorb methylene blue (MB) from water. And the magnetic particles loaded on the adsorbent were obtained through functionalizing iron and silicon ions which were extracted from the biochar by acid and alkali impregnation. Physicochemical properties of sludge-based biochar (SB) were analyzed by SEM, BET, FTIR, XRD, XPS and VSM. Compared with the original biochar, NAlSB-Fe-Si had richer pore structure and higher pore volume, and the SiO2 and Fe3O4 loading made the specific surface area increased by 200%. Possible adsorption mechanism was proposed by exploring the initial pH, MB concentration and reaction time. Results revealed that alkaline environment was more conducive to the rapid removal of cationic dyes such as MB. Pseudo-second-order kinetic model and intra-particle diffusion model could describe the adsorption behavior of MB on NAlSB-Fe-Si. The fitting results of Langmuir model showed that adsorption temperature is positively correlated with adsorption capacity, and the maximum adsorption capacity of MB on nitrogen-doped sludge-based biochar (NSB) and NAlSB-Fe-Si at 25 °C was 26.47 and 300.36 mg/g, respectively. Finally, the MB removal rate of NAlSB-Fe-Si could still reach 70% after four cycles, indicating that the composite was an efficient cationic dye adsorbent, and its preparation could be regarded as a way of resource utilization of waterworks sludge.
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Azul de Metileno , Poluentes Químicos da Água , Adsorção , Carvão Vegetal , Cinética , Esgotos , Dióxido de Silício , Poluentes Químicos da Água/análiseRESUMO
BACKGROUND: Fall incident is one of the major causes of mortality and injury in older adults. Modifiable fall risk factors are the targets for fall prevention. Since the status of some fall risk factors can change with age, insights into age-stratified fall risk factors can be beneficial for developing tailored fall prevention strategies for older adults at different ages. Therefore, the objective of this study was to identify fall risk factors in different age groups of older people. METHODS: The current study analysed data of 14,601 community-dwelling older Chinese (aged 65 years or above) recruited from the Chinese Longitudinal Healthy Longevity Survey (CLHLS, wave 2017-2018). 24 modifiable fall risk factors were selected from the CLHLS as candidate risk factors and multivariable logistic regression was used to identify significant risk factors associated with fall incidents by three age groups (65-79 years, 80-94 years, ≥95 years). RESULTS: Anxiety is identified across all age groups. Hearing impairment, stroke, rain/water leakage were found in both the 65-79 years and the 80-94 years old groups. Interactions between hearing and stroke and between hearing and rain /water leakage were found in these two groups, respectively. Medication use is a shared factor in both the 65-79 years and the ≥95 years old group. CONCLUSION: Modifiable fall risk factors varied among age groups, suggesting that customised fall prevention strategies can be applied by targeting at fall risk factors in corresponding age groups.
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Vida Independente , Acidente Vascular Cerebral , Humanos , Idoso , Idoso de 80 Anos ou mais , População do Leste Asiático , Fatores de Risco , Estudos LongitudinaisRESUMO
INTRODUCTION: Ventricular septal rupture is an important high-mortality complication in the scope of myocardial infarctions. The effectiveness of different treatment modalities is still controversial. This meta-analysis compares the efficacy of percutaneous closure vs. surgical repair for the treatment of postinfarction ventricular septal rupture (PI-VSR). METHODS: A meta-analysis was performed on relevant studies found through PubMed®, Embase, Web of Science, Cochrane Library, China National Knowledge Infrastructure (or CNKI), Wanfang Data, and VIP databases searching. The primary outcome was a comparison of in-hospital mortality between the two treatments, and the secondary outcome was documentation of one-year mortality, postoperative residual shunts, and postoperative cardiac function. Differences were expressed as odds ratios (ORs) with 95% confidence intervals (CIs) to assess the relationships between predefined surgical variables and clinical outcomes. RESULTS: Qualified studies (742 patients from 12 trials) were found and investigated for this meta-analysis (459 patients in the surgical repair group, 283 patients in the percutaneous closure group). When comparing surgical repair to percutaneous closure, it was found that the former significantly reduced in-hospital mortality (OR: 0.67, 95% CI 0.48-0.96, P=0.03) and postoperative residual shunts (OR: 0.03, 95% CI 0.01-0.10, P<0.00001). Surgical repair also improved postoperative cardiac function overall (OR: 3.89, 95% CI 1.10-13.74, P=0.04). However, there was no statistically significant difference in one-year mortality between the two surgical strategies (OR: 0.58, 95% CI 0.24-1.39, P=0.23). CONCLUSION: We found that surgical repair appears to be a more effective therapeutic option than percutaneous closure for PI-VSR.
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Procedimentos Cirúrgicos Cardíacos , Infarto do Miocárdio , Ruptura do Septo Ventricular , Humanos , Ruptura do Septo Ventricular/etiologia , Ruptura do Septo Ventricular/cirurgia , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Infarto do Miocárdio/complicações , Infarto do Miocárdio/cirurgia , Mortalidade Hospitalar , Cateterismo Cardíaco/efeitos adversos , Resultado do Tratamento , Estudos RetrospectivosRESUMO
Gliomas are the highest prevalent primary central nervous system (CNS) cancers with poor overall survival rate. There is an urgent need to conduct more research into molecular therapies targeting critical elements of gliomas. This study herein targeted to assess the impact of tripartite motif protein 6 (TRIM6) on gliomas. Using public databases, we found the increased TRIM6 expression in tissues of glioma which was linked with worst overall survival. Silencing TRIM6 promoted glioma cell proliferation, migration and angiogenesis, suggesting the promoting effects of TRIM6 on gliomas. Knockdown of TRIM6 expression downregulated the expression levels of Forkhead box M1 (FOXM1) and vascular endothelial growth factor A (VEGFA) in glioma cells. Afterwards, impact of TRIM6 on VEGFA expression was regulated by FOXM1. VEGFA overexpression reversed the decreased abilities of glioma cell proliferation, migration and angiogenesis caused by silencing TRIM6. Furthermore, we also found that TRIM6 promoted the growth of gliomas in the xenograft mouse model. In summary, the expression of TRIM6 was increased which was related to poor prognosis of glioma patients. TRIM6 promoted glioma cell proliferation, migration and angiogenesis through the FOXM1-VEGFA pathway. Therefore, TRIM6 carries capacity to be explored as a novel therapeutic target in clinical.
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Glioma , Fator A de Crescimento do Endotélio Vascular , Humanos , Animais , Camundongos , Fator A de Crescimento do Endotélio Vascular/metabolismo , Linhagem Celular Tumoral , Glioma/genética , Glioma/metabolismo , Proliferação de Células , Movimento Celular/genética , Proteínas com Motivo Tripartido/genética , Proteínas com Motivo Tripartido/farmacologia , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/farmacologiaRESUMO
Solution-processed polycrystalline perovskite film is promising for the next generation X-ray imaging. However, the spatial resolution of current perovskite X-ray panel detectors is far lower than the theoretical limit. Herein we find that the pixel level non-uniformity, also known as fixed pattern noise, is the chief culprit affecting the signal-to-noise ratio and reducing the resolution of perovskite detectors. We report a synergistic strategy of rheological engineering the perovskite suspensions to achieve X-ray flat panel detectors with pixel-level high uniformity and near-to-limit spatial resolution. Our approach includes the addition of methylammonium iodide and polyacrylonitrile to the perovskite suspension, to synergistically enhance the flowability and particle stability of the oversaturated solution. The obtained suspension perfectly suits for the blade-coating process, avoiding the uneven distribution of solutes and particles within perovskite films. The assembled perovskite panel detector exhibits greatly improved fixed pattern noise value (1.39%), high sensitivity (2.24 × 104 µC Gyair-1 cm-2), low detection limit (28.57 nGyair·s-1) as well as good working stability, close to the performance of single crystal detectors. Moreover, the detector achieves a near-to-limit resolution of 0.51 lp/pix.
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Perovskites are attracting attention for optoelectronic devices. Despite their promise, the large-scale synthesis of perovskite materials with exact stoichiometry, especially high-entropy perovskites, has been a major challenge. Moreover, the difficulty in stoichiometry control also hinders the development of perovskite X-ray flat-panel detectors. Previous reports all employed simple MAPbI3 as the active layer, while the performance still falls short of optimized single-crystal-based single-pixel detectors. Herein, a scalable and universal strategy of a mechanochemical method is adopted to synthesize stoichiometric high-entropy perovskite powders with high quality and high quantity (>1 kg per batch). By utilizing these stoichiometric perovskites, the first FA0.9 MA0.05 Cs0.05 Pb(I0.9 Br0.1 )3 -based X-ray flat-panel detector with low trap density and large mobility-lifetime product (7.5 × 10-3 cm2 V-1 ) is reported. The assembled panel detector exhibits close-to-single-crystal performance (high sensitivity of 2.1 × 104 µC Gyair -1 cm-2 and ultralow detection limit of 1.25 nGyair s-1 ), high spatial resolution of 0.46 lp/pixel, as well as excellent thermal robustness under industrial standards. The high performance in the high-entropy perovskite-based X-ray FPDs has the potential to facilitate the development of new-generation X-ray-detection systems.
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Multi-energy X-ray detection is sought after for a wide range of applications including medical imaging, security checking and industrial flaw inspection. Perovskite X-ray detectors are superior in terms of high sensitivity and low detection limit, which lays a foundation for multi-energy discrimination. However, the extended capability of the perovskite detector for multi-energy X-ray detection is challenging and has never been reported. Herein we report the design of vertical matrix perovskite X-ray detectors for multi-energy detection, based on the attenuation behavior of X-ray within the detector and machine learning algorithm. This platform is independent of the complex X-ray source components that constrain the energy discrimination capability. We show that the incident X-ray spectra could be accurately reconstructed from the conversion matrix and measured photocurrent response. Moreover, the detector could produce a set of images containing the density-graded information under single exposure, and locate the concealed position for all low-, medium- and high-density substances. Our findings suggest a new generation of X-ray detectors with features of multi-energy discrimination, density differentiation, and contrast-enhanced imaging.
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Metal halide perovskites (MHPs) have demonstrated excellent performances in detection of X-rays and gamma-rays. Most studies focus on improving the sensitivity of single-pixel MHP detectors. However, little work pays attention to the dark current, which is crucial for the back-end circuit integration. Herein, the requirement of dark current is quantitatively evaluated as low as 10-9 A/cm2 for X-ray imagers integrated on pixel circuits. Moreover, through the semiconductor device analysis and simulation, we reveal that the main current compositions of thick perovskite X-ray detectors are the thermionic-emission current (JT) and the generation-recombination current (Jg-r). The typical observed failures of p-n junctions in thick detectors are caused by the high generation-recombination current due to the band mismatch and interface defects. This work provides a deep insight into the design of high sensitivity and low dark current perovskite X-ray detectors.
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Background: Currently, there are many different drugs to improve Alzheimer's disease (AD) from different pathways. As a supplement and alternative medicine, traditional Chinese medicine (TCM) targets multiple pathways which may be different from classical Western medicine, which may be orchestrated with Western medicine to materialize multiplying efficacy in AD patients. Objective: To investigate the therapeutic effect and assess the available preclinical evidence and possible mechanisms of ß-asarone which was extracted from Acorus gramineus Soland (Araceae, AGS) for AD based on rat and mouse animal models. Methods: PubMed, Embase, Scopus, Cochrane Library, BIOSIS Previews, Web of Science, EBSCO, and Google Scholar were searched from inception to 5 May 2022. Rat and mouse experiments assessing the therapeutic effects of ß-asarone for AD were included. Primary outcomes were neuroethology, including escape latency and times of crossing platform. Second outcomes were cell apoptosis, including Bax and Bcl-2. The weighted mean difference (WMD) was generated for continuous variables. The relative outcomes were analyzed with the aid of Get Data Graph Digitizer 2.26 and software STATA version 16.0 MP. Results: For the primary endpoint, compared with the modeling group, ß-asarone significantly decreased the escape latency (WMD = -12.61, 95% CI: -18.66 to -6.57) and increased the times of crossing platform (WMD = 1.50, 95% CI: 0.31-2.70). For the secondary endpoint, ß-asarone remarkably reduced the relative expression of the amyloid precursor protein (APP) (WMD = -2.25, 95% CI: -2.49 to -2.01), decreased the expression of the apoptosis-related protein, associated X protein (Bax) (WMD = -2.40, 95% CI: -3.51 to -1.29), lowered the expression of apoptosis-related protein, B-cell lymphoma-2 (Bcl-2) (WMD = 0.42, 95% CI: 0.38-0.46), and decreased the signal pathway-related proteins, phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) (WMD = -0.70, 95% CI: -0.93 to -0.47) over the control group. Conclusion: ß-asarone spectacularly improved the learning ability and memory in rats and mice, which might be correlated with its potential neuroprotective effect through multiple signaling pathways.
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Controlling the carrier polarity and concentration underlies most electronic and optoelectronic devices. However, for the intensively studied lead halide perovskites, the doping tunability is inefficient. In this work, taking CsPbBr3 as an example, it is revealed that the coexistence of metallic Pb or CsBr3 /Br2 , rather than the precursor ratio, can provide Pb-rich/Br-poor or Br-rich/Pb-poor chemical conditions, enabling the tunability of electrical properties from weak n-type, intrinsic, to moderate p-type. Experimentally, under Br2 -exposure treatment, a shift of the Fermi level as large as 1.00 eV is achieved, which is one of the highest value among all kinds of doping methods. The X-ray detector based on the intrinsic CsPbBr3 exhibits excellent performance, with a negligible dark-current drift of 7.1 × 10-4 nA cm-1 s-1 V-1 , a low detection limit of 103.6 nGyair s-1 , and a high sensitivity of 9085 µC Gyair -1 cm-2 . This work provides a critical understanding and guidance for tuning the electrical properties of lead halide perovskites, which establishes good foundations for achieving intrinsic perovskite semiconductors and also constructing potential homojunction devices.
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The metal halide perovskites exhibit excellent performance as the direct X-ray detectors owing to their strong absorption capability, long carrier lifetime and diffusion length, radiation ruggedness, etc. For imaging applications, the ionic migration of perovskites and charge sharing effect between the adjacent pixels have a significantly negative impact on the spatial resolution. Herein, for the first time, the porous anodic aluminum oxides (AAO) have been used as a template to grow the CsPbBr2I thick film for the direct X-ray detection. Benefiting from the oxygen passivation effect, the activation energy for ionic migration has been observed to increase to 0.701 eV, whereas the dark current drift (1.01 × 10-5 nA cm-1s-1V-1) is one to two orders of magnitude lower than the other lead halide perovskite single crystals and films. Moreover, the AAO insulating wall effectively blocks the charge diffusion effect across a pixel pitch of 10 µm. Overall, the findings reported in this study open a new route for reducing the ionic migration and pixel crosstalk, thus, bringing the perovskite X-ray detectors close to the practical applications.
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Background: The development of a new strategy to overcome chemoresistance to hepatocellular carcinoma (HCC) treatment is a long-standing issue. We have previously found that upregulated SETD3 levels are closely correlated with HCC. This study aims to explore the mechanism underlying how upregulation of SETD3 promotes liver carcinogenesis. Methods: RNA-Sequencing analysis was used to explore the correlation of SETD3 with regulatory targets. In vitro assays including cell proliferation and migration were performed to study the oncogenic roles of SETD3 and PLK1. Western blotting, immunohistochemical staining, and blood biochemical assays were performed to examine protein expression or pathological index in tumor tissues and mice liver tissues. Luciferase reporter system and chromatin immunoprecipitation assays were used to explore the mechanism. Results: We revealed that SETD3 regulates gene expression in subgroups, including cell division, cell proliferation, and cell cycle, in hepatocellular tumor cells. We found that SETD3 upregulation is associated with elevated PLK1 level in both hepatic tumor cells and clinical liver tissues. We further showed that overexpression of SETD3 promoted tumor cell proliferation and migration, whereas inhibition of PLK1 activity attenuated these phenotypes caused by SETD3. By taking advantage of the Sleep Beauty transposase system, we confirmed that upregulated mouse Setd3 promoted hepatic carcinogenesis in situ, but knockdown of mouse Plk1 mitigated Setd3-promoted tumorigenesis in mice. Mechanistically, we showed that SETD3 could be recruited to the promoter of PLK1 gene to facilitate PLK1 transcription. Conclusions: Our data demonstrate that elevated SETD3 may promote HCC by enhancing PLK1 expression, which suggests that SETD3 may act as a potential drug target combined with PLK1 inhibition to treat HCC.
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Salvia miltiorrhiza (SAL) and Panax notoginseng (PNS) are widely used in treating of ischemic stroke. However, it is unknown which components of SAL and PNS protect brain microvascular pericytes after an ischemic stroke. We evaluated the protective effects and mechanisms of SAL and PNS components in pericytes subjected to oxygen-glucose deprivation/reoxygenation (OGD/R). Pericytes were subjected to OGD/R. Cell Counting Kit-8 (CCK-8) was used to evaluate cell viability. ROS and SOD kits were used to detect oxidative stress. Flow cytometry was performed to analyze cell apoptosis. To evaluate cell migration, a scratch assay was performed. Expression of cleaved caspase-3, Bcl-2, Bax, VEGF, Ang-1, PDGFR-ß, PI3K/AKT/mTOR, and JNK/ERK/P38 signaling pathways were identified using western blot. The results revealed that salvianolic acid B (Sal B), salvianolic acid D (Sal D), notoginsenoside R1 (R1), ginsenoside Rb1 (Rb1), and ginsenoside Rg1 (Rg1) increased the cell viability of pericytes subjected to OGD/R, reduced the level of ROS, and increased the expression of SOD. The components reduced cell apoptosis, increased the protein level of Bcl-2/Bax, reduced the level of cleaved caspase-3/caspase-3, increased cell migration, and enhanced the levels of Ang-1, PDGFR-ß, and VEGF. The components could activate PI3K/AKT/mTOR pathway while inhibiting the JNK/ERK/P38 pathway. Studies found that Sal B, Sal D, R1, Rb1, and Rg1 inhibited oxidative stress and apoptosis while increasing the release of pro-angiogenic regulators of pericytes related to the PI3K/AKT/mTOR and JNK/ERK/P38 signaling pathways. This provides a potential foundation for developing monomeric drugs for treating ischemic stroke.
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AVC Isquêmico , Fármacos Neuroprotetores , Panax notoginseng , Salvia miltiorrhiza , Humanos , Oxigênio/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Panax notoginseng/metabolismo , Caspase 3/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Salvia miltiorrhiza/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Proteína X Associada a bcl-2/metabolismo , Glucose/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Pericitos/metabolismo , Fármacos Neuroprotetores/farmacologia , Serina-Treonina Quinases TOR/metabolismo , Sistema de Sinalização das MAP Quinases , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , AVC Isquêmico/metabolismo , Superóxido Dismutase/metabolismo , ApoptoseRESUMO
The combined use of two or more different drugs can better promote nerve recovery and its prognosis for treatment of stroke. Salvianolate lyophilized injection (SLI) made from the aqueous extraction of salvia miltiorrhiza and Xueshuantong injection (lyophilized) (XST) made from the Panax Notoginseng extraction are two herbal standardized preparations that have been widely used in China for the treatment of ischemic stroke. In this study, we investigated the neuroprotective effects of XST combined with SLI in the recovery stage of middle cerebral artery occlusion / reperfusion (MCAO/R) injury rat. Wistar rats were subjects to MCAO/R, then were treated with SLI or XST alone, or with their combination (1X1S) via tail injection daily for 14 days. The pathological status of the brain was detected by neurological deficit scores, TTC, regional cerebral blood flow and Nissl staining. Golgi-Cox staining was used to assess dendritic, axonal and synaptic remodeling. The expression of MAP-2, ß-Tubulin, PSD95, SYN, BDNF and VEGF were analyzed by western blotting and immunofluorescence. The results showed that administration of 1X1S not only significantly decreased neurological scores and infarct volumes, but also increased regional cerebral blood flow, strengthened dendritic and synaptic remodeling compared with XST, SLI used alone. And the mechanism of combined of 1X1S to exert neuroprotection may be associated with PI3K/ AKT/ mTOR and RhoA/ROCK2 pathways. Overall, these findings suggest that combination of XST and SLI promotes dendritic spine density and synaptic plasticity via upregulation of the PI3K/ AKT/ mTOR pathways and inhabitation the RhoA/ROCK2 signaling pathway in rat with MCAO/R, showing its multiple-action-multiple-target efficacy and suggest a potential new strategy for ischemia.
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Isquemia Encefálica , Medicamentos de Ervas Chinesas , Fármacos Neuroprotetores , Traumatismo por Reperfusão , Animais , Isquemia Encefálica/tratamento farmacológico , Isquemia Encefálica/metabolismo , Medicamentos de Ervas Chinesas/uso terapêutico , Infarto da Artéria Cerebral Média/tratamento farmacológico , Isquemia/tratamento farmacológico , Plasticidade Neuronal , Fármacos Neuroprotetores/uso terapêutico , Fosfatidilinositol 3-Quinases/metabolismo , Extratos Vegetais/uso terapêutico , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Ratos Wistar , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismoRESUMO
Lead halide perovskites have exhibited excellent performance in solar cells, LEDs and detectors. Thermal properties of perovskites, such as heat capacity and thermal conductivity, have rarely been studied and corresponding devices have barely been explored. Considering the high absorption coefficient (104~105 cm-1), low specific heat capacity (296-326 J kg-1 K-1) and small thermal diffusion coefficient (0.145 mm2 s-1), herein we showcase the successful use of perovskite in optoacoustic transducers. The theoretically calculated phonon spectrum shows that the overlap of optical phonons and acoustic phonons leads to the up-conversion of acoustic phonons, and thus results in experimentally measured low thermal diffusion coefficient. The assembled device of PDMS/MAPbI3/PDMS simultaneously achieves broad bandwidths (-6 dB bandwidth: 40.8 MHz; central frequency: 29.2 MHz), and high conversion efficiency (2.97 × 10-2), while all these parameters are the record values for optoacoustic transducers. We also fabricate miniatured devices by assembling perovskite film onto fibers, and clearly resolve the fine structure of fisheyes, which demonstrates the strong competitiveness of perovskite based optoacoustic transducers for ultrasound imaging.
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Hybrid bismuth halides perovskites have emerged as promising candidates for X-ray detection, due to the strong absorptivity of high-energy X-ray photons, high resistivity, large carrier diffusion length and low toxicity. However, the mostly investigated hybrid bismuth iodides single crystals are usually opaque and require a harsh synthesis process. Herein, novel one-dimensional (1D) pentamethylenediamine bismuth bromide (PDA)BiBr5 single crystals were synthesized via an antisolvent-assisted crystallization method at room temperature. Bulk (PDA)BiBr5 single crystals have sizes of 10×1.3×1.5â mm3 and high transparency. They are shown to have low density of defects of 2.0×1010 â cm-3 and obvious photoconductivity. Moreover, they exhibit large bulk resistivity of 2.13×1011 â Ω cm and good X-ray attenuation coefficient. Consequently, the vertical structured (PDA)BiBr5 single crystal X-ray photoconductor produces a sensitivity of 3.8â µC Gyair -1 â cm-2 . This study provides a facile strategy for synthesizing bulk hybrid bismuth bromides single crystals with potential X-ray detection application.
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Direct X-ray detectors are considered as competitive next-generation X-ray detectors because of their high spatial resolution, high sensitivity, and simple device configuration. However, their potential is largely limited by the imperfections of traditional materials, such as the low crystallization temperature of α-Se and the low atomic numbers of α-Si and α-Se. Here, we report the Sb2Se3 X-ray thin-film detector with a p-n junction structure, which exhibited a sensitivity of 106.3 µC/(Gyair·cm2) and response time of < 2.5 ms. This decent performance and the various advantages of Sb2Se3, such as the average atomic number of 40.8 and µτ product (µ is the mobility, and τ is the carrier lifetime) of 1.29 × 10-5 cm2/V, indicate its potential for application in X-ray detection.
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The direct band gap CsPbBr3 perovskite is regarded as a promising alternative for low-cost and high-performance X-ray radiation detectors. Despite the fact that CsPbBr3 nanocrystals have been shown to be good scintillators in the indirect conversion mode, the direct X-ray conversion with CsPbBr3 single crystals is expected to yield higher spatial resolution. Here, rubidium (Rb) doping is demonstrated to be an efficient approach to improve carrier transport and X-ray detection performance in the direct-conversion X-ray detectors based on Cs(1-x)RbxPbBr3 single crystals. Electrical properties' characterizations as combined with X-ray photoelectron spectroscopy (XPS) measurements have revealed that Rb doping in Cs(1-x)RbxPbBr3 single crystals can enhance the atomic interaction and orbital coupling between Pb and Br atoms, leading to an enhancement of carrier transport and X-ray detection performance. X-ray detectors based on a small amount (0.037%) of Rb-doped Cs(1-x)RbxPbBr3 single crystals exhibited a high X-ray sensitivity of 8097 µC Gyair-1 cm-2. This work offers a feasible strategy to improve the X-ray detection performance by chemical doping in all-inorganic perovskite X-ray detectors.
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Radioluminescent materials (scintillators) are widely applied in medical imaging, nondestructive testing, security inspection, nuclear and radiation industries, and scientific research. Recently, all-inorganic lead halide perovskite nanocrystal (NC) scintillators have attracted great attention due to their facile solution processability and ultrasensitive X-ray detection, which allows for large area and flexible X-ray imaging. However, the light yield of these perovskite NCs is relatively low because of the strong self-absorption that reduces the light out-coupling efficiency. Here, NCs with self-trapped excitons emission are demonstrated to be sensitive, reabsorption-free scintillators. Highly luminescent and stable Cs3Cu2I5 NCs with a photoluminescence quantum yields of 73.7%, which is a new record for blue emission lead-free perovskite or perovskite-like NCs, is produced with the assistance of InI3. The PL peak of the Cs3Cu2I5 NCs locates at 445 nm that matches with the response peak of a silicon photomultiplier. Thus, Cs3Cu2I5 NCs are demonstrated as efficient scintillators with zero self-absorption and extremely high light yield (≈79 279 photons per MeV). Both Cs3Cu2I5 NC colloidal solution and film exhibit strong radioluminescence under X-ray irradiation. The potential application of Cs3Cu2I5 NCs as reabsorption-free, low cost, large area, and flexible scintillators is demonstrated by a prototype X-ray imaging with a high spatial resolution.