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Many transient receptor potential (TRP) channels respond to diverse stimuli and conditionally conduct small and large cations. Such functional plasticity is presumably enabled by a uniquely dynamic ion selectivity filter that is regulated by physiological agents. What is currently missing is a "photo series" of intermediate structural states that directly address this hypothesis and reveal specific mechanisms behind such dynamic channel regulation. Here, we exploit cryoelectron microscopy (cryo-EM) to visualize conformational transitions of the capsaicin receptor, TRPV1, as a model to understand how dynamic transitions of the selectivity filter in response to algogenic agents, including protons, vanilloid agonists, and peptide toxins, permit permeation by small and large organic cations. These structures also reveal mechanisms governing ligand binding substates, as well as allosteric coupling between key sites that are proximal to the selectivity filter and cytoplasmic gate. These insights suggest a general framework for understanding how TRP channels function as polymodal signal integrators.
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Canais de Cátion TRPV/química , Canais de Cátion TRPV/metabolismo , Regulação Alostérica , Permeabilidade da Membrana Celular/efeitos dos fármacos , Microscopia Crioeletrônica , Diterpenos/farmacologia , Células HEK293 , Humanos , Ativação do Canal Iônico , Lipídeos/química , Meglumina/farmacologia , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Prótons , Canais de Cátion TRPV/agonistasRESUMO
Thyroid hormones are vital in metabolism, growth and development1. Thyroid hormone synthesis is controlled by thyrotropin (TSH), which acts at the thyrotropin receptor (TSHR)2. In patients with Graves' disease, autoantibodies that activate the TSHR pathologically increase thyroid hormone activity3. How autoantibodies mimic thyrotropin function remains unclear. Here we determined cryo-electron microscopy structures of active and inactive TSHR. In inactive TSHR, the extracellular domain lies close to the membrane bilayer. Thyrotropin selects an upright orientation of the extracellular domain owing to steric clashes between a conserved hormone glycan and the membrane bilayer. An activating autoantibody from a patient with Graves' disease selects a similar upright orientation of the extracellular domain. Reorientation of the extracellular domain transduces a conformational change in the seven-transmembrane-segment domain via a conserved hinge domain, a tethered peptide agonist and a phospholipid that binds within the seven-transmembrane-segment domain. Rotation of the TSHR extracellular domain relative to the membrane bilayer is sufficient for receptor activation, revealing a shared mechanism for other glycoprotein hormone receptors that may also extend to other G-protein-coupled receptors with large extracellular domains.
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Microscopia Crioeletrônica , Imunoglobulinas Estimuladoras da Glândula Tireoide , Receptores da Tireotropina , Tireotropina , Membrana Celular/metabolismo , Doença de Graves/imunologia , Doença de Graves/metabolismo , Humanos , Imunoglobulinas Estimuladoras da Glândula Tireoide/química , Imunoglobulinas Estimuladoras da Glândula Tireoide/imunologia , Imunoglobulinas Estimuladoras da Glândula Tireoide/farmacologia , Imunoglobulinas Estimuladoras da Glândula Tireoide/ultraestrutura , Fosfolipídeos/metabolismo , Domínios Proteicos , Receptores Acoplados a Proteínas G/agonistas , Receptores Acoplados a Proteínas G/química , Receptores Acoplados a Proteínas G/ultraestrutura , Receptores da Tireotropina/agonistas , Receptores da Tireotropina/química , Receptores da Tireotropina/imunologia , Receptores da Tireotropina/ultraestrutura , Rotação , Tireotropina/química , Tireotropina/metabolismo , Tireotropina/farmacologiaRESUMO
More evidence shows that changes in functional connectivity with regard to brain networks and neurometabolite levels correlated to cognitive impairment in multiple sclerosis. However, the neurological basis underlying the relationship among neurometabolite levels, functional connectivity, and cognitive impairment remains unclear. For this purpose, we used a combination of magnetic resonance spectroscopy and resting-state functional magnetic resonance imaging to study gamma-aminobutyric acid and glutamate concentrations in the posterior cingulate cortex, medial prefrontal cortex and left hippocampus, and inter-network functional connectivity in 29 relapsing-remitting multiple sclerosis patients and 34 matched healthy controls. Neuropsychological tests were used to evaluate the cognitive function. We found that relapsing-remitting multiple sclerosis patients demonstrated significantly reduced gamma-aminobutyric acid and glutamate concentrations and aberrant functional connectivity involving cognitive-related networks compared to healthy controls, and both alterations were associated with specific cognition decline. Moreover, mediation analyses indicated that decremented hippocampus gamma-aminobutyric acid levels in relapsing-remitting multiple sclerosis patients mediated the association between inter-network functional connectivity in various components of default mode network and verbal memory deficits. In summary, our findings shed new lights on the essential function of GABAergic system abnormalities in regulating network dysconnectivity and functional connectivity in relapsing-remitting multiple sclerosis patients, suggesting potential novel approach to treatment.
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Disfunção Cognitiva , Esclerose Múltipla Recidivante-Remitente , Esclerose Múltipla , Humanos , Esclerose Múltipla/patologia , Esclerose Múltipla Recidivante-Remitente/complicações , Esclerose Múltipla Recidivante-Remitente/diagnóstico por imagem , Esclerose Múltipla Recidivante-Remitente/patologia , Imageamento por Ressonância Magnética , Ácido gama-Aminobutírico , Encéfalo , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/patologia , Glutamatos , Testes NeuropsicológicosRESUMO
The hierarchically organized structures of the medial temporal lobe are critically important for episodic memory function. Accumulating evidence suggests dissociable information processing pathways are maintained throughout these structures including in the medial and lateral entorhinal cortex. Cortical layers provide an additional dimension of dissociation as the primary input to the hippocampus derives from layer 2 neurons in the entorhinal cortex, whereas the deeper layers primarily receive output from the hippocampus. Here, novel high-resolution T2-prepared functional MRI methods were successfully used to mitigate susceptibility artifacts typically affecting MRI signals in this region providing uniform sensitivity across the medial and lateral entorhinal cortex. During the performance of a memory task, healthy human subjects (age 25-33 years, mean age 28.2 ± 3.3 years, 4 female) showed differential functional activation in the superficial and deep layers of the entorhinal cortex associated with task-related encoding and retrieval conditions, respectively. The methods provided here offer an approach to probe layer-specific activation in normal cognition and conditions contributing to memory impairment.SIGNIFICANCE STATEMENT This study provides new evidence for differential neuronal activation in the superficial versus deep layers of the entorhinal cortex associated with encoding and retrieval memory processes, respectively, in cognitively normal adults. The study further shows that this dissociation can be observed in both the medial and the lateral entorhinal cortex. The study was achieved by using a novel functional MRI method allowing us to measure robust functional MRI signals in both the medial and lateral entorhinal cortex that was not possible in previous studies. The methodology established here in healthy human subjects lays a solid foundation for subsequent studies investigating layer-specific and region-specific changes in the entorhinal cortex associated with memory impairment in various conditions such as Alzheimer's disease.
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Doença de Alzheimer , Memória Episódica , Adulto , Humanos , Feminino , Adulto Jovem , Córtex Entorrinal/diagnóstico por imagem , Córtex Entorrinal/fisiologia , Lobo Temporal/fisiologia , Hipocampo/diagnóstico por imagem , Hipocampo/fisiologia , Transtornos da MemóriaRESUMO
This study presents a fast and accurate data processing method for multispectral radiation thermometry that can accurately measure the true temperature of steel materials without requiring a priori emissivity model. The method generates a temperature matrix by inputting emissivity values at different wavelengths and selects a reference vector from the matrix. Then, it rearranges the temperature matrices at other wavelengths and calculates the Euclidean distance between each column element of the rearranged matrix and the reference vector. The method uses an unconstrained optimization technique to minimize the Euclidean distance and obtain the true temperature and emissivity of the object simultaneously. We evaluate the performance of the method by simulation and experiment in the response band of 1.4 â¼ 2.5â µm and temperature range of 873 â¼ 1173 K. The simulation results indicate that the relative error of the inverted temperature is within 0.229%, and the average computation time is less than 112.301 ms. The experimental results show that the maximum temperature error during the measurement process is 0.813%. Our method provides a feasible and efficient solution for real-time temperature measurement of steel materials.
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Iron Dextran is a widely used iron oxide compound to treat iron-deficiency anemia patients in the clinic. Similar to other iron oxide compounds such as Ferumoxytol, it can also be used off-label as an intravascular magnetic resonance imaging (MRI) contrast agent due to its strong iron-induced T2 and T2* shortening effects. In this study, we seek to evaluate the feasibility of using Iron Dextran enhanced multi-echo susceptibility weighted imaging (SWI) MRI at 7T to image arterial and venous blood vessels in the human brain. Phantom experiments were performed to measure the r2* relaxivity for Iron Dextran in blood, based on which the SWI sequence was optimized. Pre- and post-infusion MR images were acquired in human subjects from which maps of arteries and veins were extracted. The post-contrast SWI images showed enhanced susceptibility difference between blood and the surrounding tissue in both arteries and veins. Our results showed that the proposed Iron Dextran enhanced multi-echo SWI approach allowed the visualization of blood vessels with diameters down to ~100 µm, including small blood vessels supplying and draining small brain structures such as the hippocampus. We conclude that Iron Dextran can be an alternative iron-based MRI contrast agent for blood vessel imaging in the human brain.
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In metal smelting, precise temperature control is of vital importance for reaction rates, efficiency, and product quality. Traditional methods such as thermocouples have inherent limitations, but multispectral radiation thermometry (MRT) offers high resolution and reliability. This paper proposes a multispectral radiation thermometry platform featuring wireless data transmission, which enables remote data transfer and precise temperature measurements. The platform was meticulously calibrated, and six common emissivity models were inverted with high accuracy. The results of temperature measurements conducted at a copper smelting site demonstrated an excellent degree of agreement with those obtained using disposable thermocouples. The platform has the potential to be applied in harsh environments, offering, to our knowledge, a novel approach to temperature measurement in metal smelting processes.
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To concurrently determine the thermophysical parameters of semi-transparent materials, a novel, to the best of our knowledge, integrated approach for concurrent measurement is proposed. In the measurement setup, a high-temperature radiation source and a beam reducer are employed to minimize the influence of background radiation. In order to differentiate between the transmitted and emitted radiation in the detection signal, the radiation signals from the radiation source are measured under four different conditions, enabling the calculation of transmissivity, emissivity, and reflectivity. The reliability and accuracy of the measurement method are validated by the thermophysical parameters of sapphire, and the results demonstrate a strong agreement between the measured data and previous findings. The combined uncertainties of transmissivity and emissivity for the sapphire at 753â K are estimated, highlighting the novel contribution of this method in investigating the thermophysical parameters of semi-transparent materials.
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BACKGROUND: Inaccurate Forrest classification may significantly affect clinical outcomes, especially in high risk patients. Therefore, this study aimed to develop a real-time deep convolutional neural network (DCNN) system to assess the Forrest classification of peptic ulcer bleeding (PUB). METHODS: A training dataset (3868 endoscopic images) and an internal validation dataset (834 images) were retrospectively collected from the 900th Hospital, Fuzhou, China. In addition, 521 images collected from four other hospitals were used for external validation. Finally, 46 endoscopic videos were prospectively collected to assess the real-time diagnostic performance of the DCNN system, whose diagnostic performance was also prospectively compared with that of three senior and three junior endoscopists. RESULTS: The DCNN system had a satisfactory diagnostic performance in the assessment of Forrest classification, with an accuracy of 91.2% (95%CI 89.5%-92.6%) and a macro-average area under the receiver operating characteristic curve of 0.80 in the validation dataset. Moreover, the DCNN system could judge suspicious regions automatically using Forrest classification in real-time videos, with an accuracy of 92.0% (95%CI 80.8%-97.8%). The DCNN system showed more accurate and stable diagnostic performance than endoscopists in the prospective clinical comparison test. This system helped to slightly improve the diagnostic performance of senior endoscopists and considerably enhance that of junior endoscopists. CONCLUSION: The DCNN system for the assessment of the Forrest classification of PUB showed satisfactory diagnostic performance, which was slightly superior to that of senior endoscopists. It could therefore effectively assist junior endoscopists in making such diagnoses during gastroscopy.
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Úlcera Péptica Hemorrágica , Humanos , Úlcera Péptica Hemorrágica/diagnóstico , Úlcera Péptica Hemorrágica/classificação , Estudos Retrospectivos , Masculino , Pessoa de Meia-Idade , Feminino , Inteligência Artificial , Redes Neurais de Computação , Curva ROC , Estudos Prospectivos , Idoso , Gravação em Vídeo , Gastroscopia/métodos , Reprodutibilidade dos Testes , AdultoRESUMO
The incidence of coccidioidomycosis continues to increase. The diagnosis frequently relies on non-invasive diagnostic testing with immunodiffusion and complement fixation (CF) testing the current gold standard. A direct comparison of quantitative immunodiffusion and CF for IgG antibodies has not been previously reported. In a comparison of 368 samples, there was close concordance observed (360/368 = 97.8%) (P-value < .001). These tests can be considerably interchangeable in the reference laboratory setting.
There are several diagnostic methodologies available in coccidioidomycosis. Direct comparisons of these methods are limited. Prior studies have not compared quantitative immunodiffusion to complement fixation testing. Our results show these tests are highly concordant.
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Coccidioides , Coccidioidomicose , Animais , Testes de Fixação de Complemento/veterinária , Anticorpos Antifúngicos , Coccidioidomicose/diagnóstico , Coccidioidomicose/veterinária , Imunodifusão/veterináriaRESUMO
BACKGROUND AND AIM: Chromoendoscopy with the use of indigo carmine (IC) dye is a crucial endoscopic technique to identify gastrointestinal neoplasms. However, its performance is limited by the endoscopist's skill, and no standards are available for lesion identification. Thus, we developed an artificial intelligence (AI) model to replace chromoendoscopy. METHODS: This pilot study assessed the feasibility of our novel AI model in the conversion of white-light images (WLI) into virtual IC-dyed images based on a generative adversarial network. The predictions of our AI model were evaluated against the assessments of five endoscopic experts who were blinded to the purpose of this study with a staining quality rating from 1 (unacceptable) to 4 (excellent). RESULTS: The AI model successfully transformed the WLI of polyps with different morphologies and different types of lesions in the gastrointestinal tract into virtual IC-dyed images. The quality ratings of the real IC-dyed and AI images did not significantly differ concerning surface structure (AI vs IC: 3.08 vs 3.00), lesion border (3.04 vs 2.98), and overall contrast (3.14 vs 3.02) from 10 sets of images (10 AI images and 10 real IC-dyed images). Although the score depended significantly on the evaluator, the staining methods (AI or real IC) and evaluators had no significant interaction (P > 0.05) with each other. CONCLUSION: Our results demonstrated the feasibility of employing AI model's virtual IC staining, increasing the possibility of being employed in daily practice. This novel technology may facilitate gastrointestinal lesion identification in the future.
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Inteligência Artificial , Lesões Pré-Cancerosas , Humanos , Projetos Piloto , Endoscopia/métodos , Índigo Carmim , Carmim , Lesões Pré-Cancerosas/diagnóstico por imagemRESUMO
BACKGROUND AND AIM: Atherosclerosis is becoming a significant health burden. Serum uric acid (SUA) is the final enzymatic product of purine metabolism and can contribute to the development of atherosclerosis. The aim of this study was to explore the possible predictive value of SUA in the development of atherosclerosis in a healthy Chinese population. METHODS AND RESULTS: In this study, a total of 11,222 healthy subjects with no carotid plaque at baseline were enrolled and divided into sex-specific groups, and then the occurrence of carotid plaque during the follow-up time was documented. The association between carotid plaque and SUA levels was examined using Cox proportional-hazards regression models. The mean SUA level was 5.35 ± 1.41 mg/dL. A total of 2,911 individuals (25.94%) developed carotid plaque during the follow-up time, including 1,071 females and 1,840 males. After adjusting for potential confounding factors, the hazard ratio (HR) and 95% confidence interval (95% CI) in women for the occurrence of carotid plaque associated with SUA levels were 1.163 (1.017-1.330), but no significant correlation was found in men, as the HR was 1.050 (0.965-1.143). CONCLUSION: Our results indicate that SUA levels predict the development of carotid plaque independent of traditional risk factors only in women.
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Aterosclerose , Ácido Úrico , Masculino , Humanos , Feminino , Estudos de Coortes , Aterosclerose/diagnóstico , Aterosclerose/epidemiologia , Fatores de Risco , China/epidemiologiaRESUMO
OBJECTIVE: To explore the genetic basis for a fetus with nuchal cystic hygroma identified in the first trimester and cholecystomegaly identified in the middle trimester of pregnancy. METHODS: A 27-year-old pregnant woman who had presented at the Antenatal Diagnostic Center of Jinan Maternal and Child Health Care Hospital on October 25, 2018 was selected as the study subject. Chorionic villus sampling was carried out in the first trimester for chromosomal karyotyping and SNP-Array analysis. Amniocentesis was carried out in the second trimester, and peripheral blood of the couple was collected at the same time. Trio whole exome sequencing (WES) was carried out, and candidate variant was verified by Sanger sequencing and bioinformatic analysis. RESULTS: No abnormality was found by chromosomal karyotyping and SNP-Array, whilst high-throughput sequencing revealed that the fetus had harbored a heterozygous c.7732A>T (p.K2578X) nonsense variant of the NIPBL gene. Following elected abortion, the autopsy results were consistent with features of Cornelia de Lange syndrome (CdLS). The same variant was detected in neither parents and was unreported in the literature. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), it was classified as pathogenic (PVS1+PS2+PM2_Supporting+PP3). CONCLUSION: The novel nonsense variant of the NIPBL gene probably underlay the genetic etiology of CdLS in this fetus. Above finding has also enriched the mutational spectrum of the NIPBL gene.
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Proteínas de Ciclo Celular , Síndrome de Cornélia de Lange , Diagnóstico Pré-Natal , Humanos , Feminino , Gravidez , Síndrome de Cornélia de Lange/genética , Adulto , Diagnóstico Pré-Natal/métodos , Proteínas de Ciclo Celular/genética , Feto/anormalidades , Sequenciamento do ExomaRESUMO
The unknown emissivity still poses a significant challenge in the data processing of Multispectral radiation thermometry (MRT). In order to achieve global optimal solution with fast convergence speed and strong robustness, a systematic comparative analysis of particle swarm optimization (PSO) and simulated annealing (SA) algorithms in the application in MRT is presented in this paper. The simulations of six hypothetical emissivity models were compared, and the results indicate that the PSO algorithm is superior to the SA algorithm in accuracy, efficiency and stability. The measured data of the surface temperature of rocket motor nozzle is simulated by the PSO algorithm, the maximum absolute error and the maximum relative error are 16.27â K and 0.65%, and the calculation time is less than 0.3 s. The superior performance of the PSO algorithm indicates that it can be well used in data processing for accurate temperature measurement in MRT, and the method proposed in this paper can be extended to other multispectral systems and applied to various industrial processes under high temperature conditions.
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In this paper, what we believe to be, a new combined algorithm of artificial bee colony and slime mould algorithm (CABCSMA) and a differential evolution (DE) algorithm using target-to-best variation strategy are proposed to process the data based on Planck's radiation law and the mathematical model of reference temperature. The material model with 6 different emissivity trends is simulated. Simulation results show that the average relative error of CABCSMA algorithm is less than 0.68%, and the average calculation time is 0.44s. The average relative error of DE algorithm is less than 0.43%, and the average calculation time is only 0.06s. The two algorithms were applied to the temperature test of silicon carbide sample, tungsten material and rocket engine nozzle. The experimental results show that the relative error of silicon carbide experimental temperature is less than 0.41% and 0.28%, and the relative error of tungsten material experimental temperature is less than 0.31% and 0.3%. The relative errors of rocket engine nozzle temperature experiments are within 0.68% and 0.52%, respectively. The results show that these two algorithms are expected to be applied in practical measurement scenarios.
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Accurate temperature measurement has significant implications for product quality, industrial process control, and scientific research. As a non-contact temperature measurement method with broad application prospects, multispectral thermometry still poses significant challenges in data processing. Currently, most multispectral thermometry methods use the Wien approximation equation to construct the objective function. However, the use of the Wien approximation equation is conditional and generally applicable only to low temperatures or short wavelengths. In this paper, what we believe is a new data processing model of multispectral thermometry is established based on the Planck formula; Additionally, a feasible region constraint method is proposed to constrain the emissivity range; By utilizing a hybrid metaheuristic optimization algorithm based on differential evolution (DE) and multi-population genetic (MPG) algorithms, the simulation results of six different models and experimental results of silicon carbide demonstrate that the proposed algorithm achieves an average relative error in temperature measurement within 0.42% and a random relative error within 0.79%. The average computation time for each temperature inversion is approximately 0.26 seconds. The accuracy and efficiency of the algorithm ensure that it can be applied to real-time temperature measurement in industrial field.
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Accumulating data have revealed the pivotal function of tripartite motif protein 38 (TRIM38) in tumors. In view of this, this investigation aims to explore the function and potential mechanism of TRIM38 in non-small cell lung cancer (NSCLC). A xenotypic tumor model was established in vivo by subcutaneously injecting NSCLC cells (2 × 106 cells) in tail vein of each mouse. Relative expression of TRIM38 mRNA was detected via quantitative real-time polymerase chain reaction (qRT-PCR). For exploring the role of TRIM38 in vivo and in vitro, mice or NSCLC cells were divided into two groups: the vector group and the TRIM38 overexpression group. Also, protein expression levels of TRIM38, Vimentin, E-cadherin, and N-cadherin were determined using western blotting and immunohistochemistry staining. Tumor nodules of mouse lung tissues were assessed via performing H&E staining. Moreover, proliferation of NSCLC cells was evaluated through colony formation and CCK-8 assays. Further, migration and invasion of NSCLC cells were assessed through wound healing and transwell assays. Protein levels of pathway-related proteins including p-p65, p65, IκB, p-IκB, p-AMPK, AMPK, and NLRP3 were examined through western blotting analysis. Tumor lung tissues of mice and NSCLC cells showed low protein and mRNA expression of TRIM38. Functionally, up-regulation of TRIM38 reduced the number of tumor nodules and suppressed epithelial-to-mesenchymal transition (EMT) in lung tissues of mice. Furthermore, up-regulation of TRIM38 in NSCLC cells inhibited migration, invasion, EMT, and proliferation. With respect to the mechanism, in vivo experiments, the inhibitory effects of TRIM38 overexpression on tumor nodules, and EMT were reversed by AMPK inhibitor. In vitro experiments, TRIM38 overexpression caused down-regulation of p-IκB and p-p65 as well as up-regulation of p-AMPK. The inhibitory effects of TRIM38 overexpression on migration, proliferation, invasion, and EMT of NSCLC cells were reversed by overexpression of NLRP3. Concurrently, AMPK inhibitor enhanced the TRIM38-overexpressed NSCLC cell's abilities in migration, clone formation, invasion, and proliferation. TRIM38 regulated the AMPK/NF-κB/NLRP3 pathway to suppress the NSCLC's progression and development.
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The 2,2'-bipyridyl-6,6'-dicarboxylate ligand (bdc) has been shown in prior work to effectively capture the uranyl(VI) ion, UO22+, from aqueous solutions. However, the redox properties of the uranyl complex of this ligand have not been addressed despite the relevance of uranium-centered reduction to the nuclear fuel cycle and the presence of a bipyridyl core in bdc, a motif long recognized for its ability to support redox chemistry. Here, the bdc complex of UO22+ (1-UO2) has been synthetically prepared and isolated under nonaqueous conditions for the study of its reductive chemical and electrochemical behavior. Spectrochemical titration data collected using decamethylcobaltocene (Cp*2Co) as the reductant demonstrate that 1e- reduction of 1-UO2 is accessible, and companion near-infrared and infrared spectroscopic data, along with theoretical findings from density functional theory, provide evidence that supports the accessibility of the U(V) oxidation state. Data obtained for control ruthenium complexes of bdc and related polypyridyl dicarboxylate ligands provide a counterpoint to these findings; ligand-centered reduction of bdc in these control compounds occurs at potentials more negative than those measured for reduction of 1-UO2, further supporting the generation of uranium(V) in 1-UO2. Taken together, these results underscore the usefulness of bdc as a ligand for actinyl ions and suggest that it could be useful for further studies of the reductive activation of these unique species.
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Effective spacecraft thermal control technologies are essential to avoid undesirable effects caused by extreme thermal conditions. In this paper, we demonstrate a transparent smart radiation device (TSRD) based on vanadium dioxide (VO2) and a hyperbolic metamaterial (HMM) structure. Using the topological transition property of HMM, high transmission in the visible band and high reflection in the infrared can be achieved simultaneously. The variable emission essentially originates from the phase change material VO2 film. Due to the high reflection of HMM in the infrared band, it can form Fabry-Pérot (FP) resonance with the VO2 film after adding the dielectric layer SiO2, which further enhances the emission modulation. Under optimized conditions, solar absorption can be reduced to 0.25, while emission modulation can reach 0.44 and visible transmission can be up to 0.7. It can be found that the TSRD can simultaneously achieve infrared variable emission, high visible transparency and low solar absorption. The HMM structure instead of traditional metal reflectors offers the possibility to achieve high transparency. In addition, the formation of FP resonance between the VO2 film and HMM structure is the key to achieving variable emission. We believe that this work can not only provide a new approach for the design of spacecraft smart thermal control devices, but also show great potential for application in spacecraft solar panels.
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Optical hydrogen sensors possess significant potential in various fields, including aerospace and fuel cell applications, which is due to their compact design and immunity to electromagnetic interference. However, commonly used sensors mostly use single-band sensing, which increases the risk of inaccurate measurements due to environmental interference or operational errors. To address this issue, this study proposes a dual-band hydrogen sensor comprising a Pd metal layer, a dielectric spacer layer, a defect layer, and a photonic crystal. By leveraging the interaction between the defect mode in the excitonic microcavity structure and the Tamm plasmon polaritons (TPPs) and Fabry-Perot (FP) resonances, the structure simultaneously generates two near-zero resonance valleys in the visible wavelength range. By adjusting the thickness of the defect layer, the coupling effect of the defect mode and TPPs together with FP resonance respectively is optimized. When the thickness is 0.27 µm, the sensitivities of the Tamm resonance band and FP resonance band are 239 and 21 RIU-1, respectively. Compared with the common sensors with a single band, its low-sensitivity wavelength can be used as a reference to assist the high-sensitivity wavelength for sensing. In addition, we find that the proposed sensor, through calculation, has good fault tolerance for both the thickness of the defect layer and the incident light angle. This study demonstrates a dual-band hydrogen sensor with TPPs, which is important for exploring new optical hydrogen sensors.