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After epiphyseal fracture, the epiphyseal plate is prone to ischemia and hypoxia, leading to the formation of bone bridge and deformity. However, the exact mechanism controlling the bone bridge formation remains unclear. Notch/RBPJ signaling axis has been indicated to regulate angiogenesis and osteogenic differentiation. Our study aims to investigate the mechanism of bone bridge formation after epiphyseal plate injury, and to provide a theoretical basis for new therapeutic approaches to prevent the bone bridge formation. The expression of DLL4 and RBPJ was significantly up-regulated in HUVECs after ischemia and hypoxia treatment. Notch/RBPJ pathway positively regulated the osteogenic differentiation of BMSCs. HUVECs can induce osteogenic differentiation of BMSCs under ischemia and hypoxia. Notch/RBPJ pathway is involved in the regulation of the trans-epiphyseal bridge formation. Notch/RBPJ in HUVECs is associated with osteogenic differentiation of BMSCs and may participate in the regulation of the bone bridge formation across the epiphyseal plate.
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Diferenciação Celular , Células Endoteliais da Veia Umbilical Humana , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina , Neovascularização Fisiológica , Osteogênese , Receptores Notch , Transdução de Sinais , Humanos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Receptores Notch/metabolismo , Receptores Notch/genética , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina/metabolismo , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina/genética , Hipóxia Celular , Células-Tronco Mesenquimais/metabolismo , Células-Tronco Mesenquimais/citologia , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Células Cultivadas , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ligação ao Cálcio/genética , AngiogêneseRESUMO
IMPORTANCE: The biogenesis and clinical application of serum HBV pgRNA have been a research hotspot in recent years. This study further characterized the heterogeneity of the 3' terminus of capsid RNA by utilizing a variety of experimental systems conditionally supporting HBV genome replication and secretion, and reveal that the 3' truncation of capsid pgRNA is catalyzed by cellular ribonuclease(s) and viral RNaseH at positions after and before 3' DR1, respectively, indicating the 3' DR1 as a boundary between the encapsidated portion of pgRNA for reverse transcription and the 3' unprotected terminus, which is independent of pgRNA length and the 3' terminal sequence. Thus, our study provides new insights into the mechanism of pgRNA encapsidation and reverse transcription, as well as the optimization of serum HBV RNA diagnostics.
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Capsídeo , Genoma Viral , Vírus da Hepatite B , RNA Viral , Replicação Viral , Capsídeo/metabolismo , Genoma Viral/genética , Hepatite B/diagnóstico , Hepatite B/virologia , Vírus da Hepatite B/genética , Vírus da Hepatite B/crescimento & desenvolvimento , Vírus da Hepatite B/metabolismo , Transcrição Reversa , Ribonuclease H/metabolismo , RNA Viral/genética , RNA Viral/metabolismo , Replicação Viral/genéticaRESUMO
Lithium-sulfur batteries (LiSBs) with high energy density still face challenges on sluggish conversion kinetics, severe shuttle effects of lithium polysulfides (LiPSs), and low blocking feature of ordinary separators to LiPSs. To tackle these, a novel double-layer strategy to functionalize separators is proposed, which consists of Co with atomically dispersed CoN4 decorated on Ketjen black (Co/CoN4@KB) layer and an ultrathin 2D Ti3C2Tx MXene layer. The theoretical calculations and experimental results jointly demonstrate metallic Co sites provide efficient adsorption and catalytic capability for long-chain LiPSs, while CoN4 active sites facilitate the absorption of short-chain LiPSs and promote the conversion to Li2S. The stacking MXene layer serves as a microscopic barrier to further physically block and chemically anchor leaked LiPSs from the pores and gaps of the Co/CoN4@KB layer, thus preserving LiPSs within efficient anchoring-conversion reaction interfaces to balance the accumulation of "dead S" and Li2S. Consequently, with an ultralight loading of Co/CoN4@KB-MXene, the LiSBs exhibit amazing electrochemical performance even under high sulfur loading and lean electrolyte, and the outperforming performance for lithium-selenium batteries (LiSeBs) can also be achieved. This work exploits a universal and effective strategy of a double-layer functionalized separator to regulate the equilibrium adsorption-catalytic interface, enabling high-energy and long-cycle LiSBs/LiSeBs.
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Hepatocellular carcinoma (HCC) is one of the main principal causes of cancer death, and the late definite diagnosis limits therapeutic approaches in time. The early diagnosis of HCC is essential, and the previous investigations on the biomarkers inferred that the γ-glutamyltranspeptidase (GGT) level could indicate the HCC process. Herein, a near-infrared fluorescence/photoacoustic (NIRF/PA) bimodal probe, CySO3-GGT, was developed for monitoring the GGT level and thus to image the HCC process. After the in-solution tests, the bimodal response was convinced. The various HCC processes were imaged by CySO3-GGT at the cellular level. Then, the CCl4-induced HCC (both induction and treatment) and the subcutaneous and orthotopic xenograft mice models were selected. All throughout the tests, CySO3-GGT achieved NIRF and PA bimodal imaging of the HCC process. In particular, CySO3-GGT could effectively realize 3D imaging of the HCC nodule by visualizing the boundary between the tumor and the normal tissue. The information here might offer significant guidance for the dynamic monitoring of HCC in the near future.
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Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Animais , Camundongos , Carcinoma Hepatocelular/diagnóstico por imagem , Neoplasias Hepáticas/diagnóstico por imagem , Corantes Fluorescentes , Imagem Óptica/métodos , XenoenxertosRESUMO
Mixing in microfluidic channels is dominated by diffusion owing to the absence of chaotic flow. However, high-efficiency microscale mixing over short distances is desired for the development of lab-on-chip systems. Here, enhanced mixing in microchannels achieved using magnetic nonspherical particles (MNSPs), is reported. Benefiting from the nonspherical shape of the MNSPs, secondary vortices exhibiting cyclical characteristics appear in microchannels when the MNSPs rotate under an external magnetic field. Increasing the rotation rate enlarges the secondary vortices, expanding the mixing zone and enhancing the mixing, resulting in a mixing efficiency exceeding 0.9 at Re of 0.069-0.69. Complementary micro-particle image velocimetry (µPIV) for flow field analysis clarifies the mixing mechanism. In addition, a chaotic vortex area is generated in the presence of two MNSPs, which shortens the distance required for achieving an appropriate mixing efficiency. This study demonstrates the potential of employing MNSPs as efficient mixers in lab-on-chip devices.
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Nanozymes, a class of catalytic nanomaterials, have shown great potential to substitute natural enzymes in various applications. Nevertheless, the pursuit of high-efficiency peroxidase-like activity in a wide pH range is one of the major challenges existing in designing nanozymes. A feasible strategy is to construct an artificial active center by using porous materials as stable supporting structures, which can actively modulate biocatalytic activities via their porous atomic structures and more active sites. Herein, a gold nanoparticles/metal-organic framework (MOF) heterostructure was prepared using UiO-66 as a stable support structure (Au NPs/UiO-66), which demonstrates enhanced peroxidase-like activity, â¼8.95 times higher than that of pure Au NPs. Strikingly, Au NPs/UiO-66 exhibits excellent stability (maintains above 80% activity at 40-70 °C and retains 93% activity after 3 months of storage) and sustained high relative activity (above 90%) over a pH range of 5.0-9.0 due to the homogeneous dispersibility of free-ligand Au NPs and the strong chemical interaction between the Au NPs and the UiO-66 host. Moreover, a colorimetric assay of ascorbic acid (AA) and three AA-related biological enzymes was developed based on Au NPs/UiO-66 nanozyme, which has a good linear detection range and excellent anti-interference ability. This work provides important guidance for the expansion of metal NPs/MOF heterostructure nanozymes and their application prospects in the development of biosensors.
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Nanopartículas Metálicas , Estruturas Metalorgânicas , Ácido Ascórbico/análise , Estruturas Metalorgânicas/química , Ouro/química , Nanopartículas Metálicas/química , Peroxidases , Concentração de Íons de Hidrogênio , Peróxido de HidrogênioRESUMO
Exosomes, as potent intercellular communication tools, have garnered significant attention due to their unique cargo-carrying capabilities, which enable them to influence diverse physiological and pathological functions. Extensive research has illuminated the biogenesis, secretion, and functions of exosomes. These vesicles are secreted by cells in different states, exerting either protective or harmful biological functions. Emerging evidence highlights their role in cardiovascular disease (CVD) by mediating comprehensive interactions among diverse cell types. This review delves into the significant impacts of exosomes on CVD under stress and disease conditions, including coronary artery disease (CAD), myocardial infarction, heart failure, and other cardiomyopathies. Focusing on the cellular signaling and mechanisms, we explore how exosomes mediate multifaceted interactions, particularly contributing to endothelial dysfunction, oxidative stress, and apoptosis in CVD pathogenesis. Additionally, exosomes show great promise as biomarkers, reflecting differential expressions of NcRNAs (miRNAs, lncRNAs, and circRNAs), and as therapeutic carriers for targeted CVD treatment. However, the specific regulatory mechanisms governing exosomes in CVD remain incomplete, necessitating further exploration of their characteristics and roles in various CVD-related contexts. This comprehensive review aims to provide novel insights into the biological implications of exosomes in CVD and offer innovative perspectives on the diagnosis and treatment of CVD.
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Doenças Cardiovasculares , Doença da Artéria Coronariana , Exossomos , MicroRNAs , Infarto do Miocárdio , Humanos , Exossomos/metabolismo , Doenças Cardiovasculares/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Infarto do Miocárdio/metabolismo , Doença da Artéria Coronariana/metabolismoRESUMO
Whether pinocembrin (PCN) could be used to alleviate hip fracture-induced pain is investigated in this research. Aged rats with hip fractures were treated with vehicle or 80 mg/kg/day PCN from week 3 to week 4. Then, hind paw mechanical allodynia, unweighting, warmth, and thickness were measured. The microglia and astrocytes activation and proliferation markers in the spinal dorsal horn were detected with real-time PCR and immunofluorescence staining. The relative expression of substance P and its receptor, tachykinin receptor 1 (Tacr1), was detected with enzyme-linked immunosorbent assay (ELISA) and Western blots. The antinociceptive effect of Tacr1 inhibitor LY303870 was also testified. PCN alleviated hip fracture-induced hind paw nociceptive (allodynia and unweighting) and vascular changes (warmth and thickness) in aged rats with diminished microglia and astrocytes activation and proliferation in the spinal dorsal horn. Upregulated substance P and Tacr1 were induced after hip fracture, which could be reversed by PCN treatment. Furthermore, LY303870 treatment partially reversed both spinal nociceptive sensitization and vascular changes after hip fracture. Substance P signaling contributes to the nociceptive and vascular changes observed in the hip fracture, which could be alleviated by PCN.NEW & NOTEWORTHY Substance P signaling contributes to the nociceptive and vascular changes observed in hip fracture, which could be alleviated by PCN.
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Envelhecimento , Flavanonas/farmacologia , Fraturas do Quadril/tratamento farmacológico , Antagonistas dos Receptores de Neurocinina-1/farmacologia , Dor/tratamento farmacológico , Substância P/efeitos dos fármacos , Animais , Modelos Animais de Doenças , Flavanonas/administração & dosagem , Fraturas do Quadril/complicações , Fraturas do Quadril/metabolismo , Indóis/farmacologia , Masculino , Antagonistas dos Receptores de Neurocinina-1/administração & dosagem , Dor Nociceptiva/tratamento farmacológico , Dor Nociceptiva/etiologia , Dor Nociceptiva/metabolismo , Dor/etiologia , Dor/metabolismo , Piperidinas/farmacologia , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacosRESUMO
Exploiting low cost, water-soluble, and near-infrared (NIR) emissive electrochemiluminophores (ECLphores) is significantly important for biological applications. In this study, bright and NIR electrogenerated chemiluminescence (ECL) emissive copper nanoclusters (Cu NCs) were synthesized through a facile one-pot wet chemical reduction method. ECL properties of obtained Cu NCs were examined in the presence of potassium persulfate, resulting in maximum intensity at 735 nm, at least 135 nm red-shifted with respect to all other Cu NCs. Electrochemistry, photoluminescence (PL), and spooling ECL spectroscopies were used to track NIR ECL emission of Cu NCs ascribed to the monomeric excited states. Due to the abundant binding sites of bovine serum albumin (BSA) to anchor target biomolecules, a sandwich-type ECL immunosensor was thus fabricated using such BSA-templated Cu NCs as tags and alpha fetoprotein antigen (AFP) as a model protein for the first time. Without assisting any signal amplification strategies, the proposed NIR ECL biosensor exhibited a wide linear range (1-400 ng mL-1) and low detection limit (0.02 ng mL-1) as well as superior selectivity and reproducibility and was successfully applied in real human serum sample determination. This work sets the stage for the development of novel non-noble metal nanoclusters for large-scale and emerging nanotechnology applications.
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Técnicas Biossensoriais , Nanopartículas Metálicas , Cobre/química , Técnicas Eletroquímicas , Humanos , Imunoensaio , Luminescência , Medições Luminescentes/métodos , Nanopartículas Metálicas/química , Reprodutibilidade dos Testes , Soroalbumina Bovina , alfa-FetoproteínasRESUMO
In this paper, a Luneburg lens-based multi-beam orbital angular momentum (OAM) antenna is proposed to achieve the 2D beam scanning capability of dual-mode OAM beams. The proposed design is composed of nine compact dual-mode antennas as sources, and a 3D-printed Luneburg lens. The sources, i.e., octagonal patch antennas, can radiate both right-handed circularly polarized (RHCP) and left-handed circularly polarized (LHCP) OAM beams with mode number l = ±1 by switching the input ports. Then, the sources are put at multiple focal points of the Luneburg lens to generate the OAM beams in different directions, and the directivities of the OAM beams are also enhanced by the Luneburg lens. The proposed design can realize nine dual-mode OAM beams with ±30° beam scanning range in two orthogonal planes. It should be noted that the proposed design can be expanded to achieve a larger number of beams with a periodic extension of the source antennas, also a wider beam scanning range with a Luneburg lens of a larger radius.
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A convenient and sensitive antioxidant assay with high performance is essential for assessing food quality and monitoring the oxidative stress level of biological matrices. Although coordination polymer nanoparticles (CPNs)-based nanozymes have emerged as candidates in the analytical field, strategies to improve the catalytic activity of CPNs have been scarcely revealed and studied. Herein, we demonstrate a manganese (Mn) doping strategy to enhance the peroxidase-mimetic activity of Fe-based CPNs. By tuning the Mn doping amounts and selecting 2,5-dihydroxyterephthalic acid (H4DHTP) as ligands, the produced nanozymes in amorphous state followed the catalytic activity order of Fe5Mn-DHTP > Fe8Mn-DHTP > Fe2Mn-DHTP > Fe-DHTP > Mn-DHTP. Ulteriorly, benefitting from the best catalytic performance and definite catalytic mechanism of Fe5Mn-DHTP, versatile colorimetric assays for ultrasensitive detection of one exogenous antioxidant (ascorbic acid, AA) and two endogenous antioxidants (glutathione, GSH; cysteine, Cys) have been deftly devised based on the inhibition of the 3,3',5,5'-tetramethylbenzidine chromogenic reaction in presence of H2O2. It was found that mercaptan (GSH and Cys) and AA exhibited different inhibition mechanisms. Practically, such a colorimetric assay was viable to determine the total antioxidant capacity of drugs and foods with desirable results. This work proposes a feasible strategy for embellishing CPN nanozymes used for designing sensitive and convenient assays for various antioxidants based on an explicit detection mechanism.
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Colorimetria , Nanopartículas , Antioxidantes , Peróxido de Hidrogênio , Ferro , Manganês , Peroxidase , Peroxidases , PolímerosRESUMO
BACKGROUND: The pathogenesis of chronic rhinosinusitis (CRS) is still unclear, and little is known about angiogenesis in this disease. We utilized a fully convolutional network (FCN), which has been extensively used in image processing to study angiogenesis in CRS. OBJECTIVE: To explore the tissue quantification of microvessels and their potential association with inflammation in CRS by using FCN to reflect the angiogenesis condition in CRS. METHODS: For endotyping of CRS, tissue homogenates of 79 patients with CRS who had undergone functional endoscopic sinus surgery and 17 control subjects were analyzed for interferon gamma, transforming growth factor beta, interleukin (IL)-1ß, IL-5, IL-6, IL-8, IL-10, IL-17, tumor necrosis factor alpha, eosinophilic cationic protein, immunoglobulin E, and Staphylococcus aureus-immunoglobulin E(SE-IgE). A total of 552 hematoxylin and eosin-stained images of 27 CRS tissue samples were used to develop an FCN, going through training, validation, and evaluation processes. An optimized FCN was applied to quantify the microvessels of tissue samples of all subjects. Correlation analysis between microvessel quantification with phenotype, endotype, clinical characteristics, and cytokine expression of CRS was carried out. RESULTS: Quantification of microvessels in type 2 and non-type 2 CRS demonstrated considerable differences, with a higher expression in type 2 CRS. There was a strong negative correlation between the area ratio of microvessels with tissue tumor necrosis factor alpha and transforming growth factor beta levels and a mildly positive correlation with tissue IL-5 and eosinophilic cationic protein concentration. CONCLUSION: FCN proved to facilitate the analysis of microvessels in airway tissue samples. This study elucidated the close association of angiogenesis with endotyping, suggesting that treatment aiming at antagonizing angiogenesis may assist to the therapy for the recrudescent and refractory CRS.
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Pólipos Nasais , Rinite , Sinusite , Doença Crônica , Proteína Catiônica de Eosinófilo , Humanos , Imunoglobulina E , Inflamação , Interleucina-5 , Microvasos , Redes Neurais de Computação , Fator de Crescimento Transformador beta , Fator de Necrose Tumoral alfaRESUMO
Hepatitis E is an increasingly serious worldwide public health problem that has attracted extensive attention. It is necessary to accurately predict the incidence of hepatitis E to better plan ahead for future medical care. In this study, we developed a Bi-LSTM model that incorporated meteorological factors to predict the prevalence of hepatitis E. The hepatitis E data used in this study are collected from January 2005 to March 2017 by Jiangsu Provincial Center for Disease Control and Prevention. ARIMA, GBDT, SVM, LSTM and Bi-LSTM models are adopted in this study. The data from January 2009 to September 2014 are used as the training set to fit models, and data from October 2014 to March 2017 are used as the testing set to evaluate the predicting accuracy of different models. Selecting models and evaluating the effectiveness of the models are based on mean absolute per cent error (MAPE), root mean square error (RMSE) and mean absolute error (MAE). A total of 44 923 cases of hepatitis E are detected in Jiangsu Province from January 2005 to March 2017. The average monthly incidence rate is 0.35 per 100 000 persons in Jiangsu Province. Incorporating meteorological factors of temperature, water vapour pressure, and rainfall as a combination into the Bi-LSTM Model achieved the state-of-the-art performance in predicting the monthly incidence of hepatitis E, in which RMSE is 0.044, MAPE is 11.88%, and MAE is 0.0377. The Bi-LSTM model with the meteorological factors of temperature, water vapour pressure, and rainfall can fully extract the linear and non-linear information in the hepatitis E incidence data, and has significantly improved the interpretability, learning ability, generalisability and prediction accuracy.
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Hepatite E , China/epidemiologia , Hepatite E/epidemiologia , Humanos , Incidência , Aprendizado de Máquina , PrevalênciaRESUMO
BACKGROUND: Overweight and obesity are major public health crises among children and adolescents and contribute to a significant economic burden. We aimed to investigate the relationship between breastfeeding duration and overweight and obesity in children and adolescents in Qingdao, China in 2017. METHODS: This study conducted a survey with 10,753 students (5370 boys and 5383 girls) aged 6 to 16 years from the Shibei District of Qingdao, China in 2017. Anthropometric measurements were taken by well-trained personnel and self-completed questionnaires were used to collect data from students. A variety of statistical methods were used in this study, including univariate and multivariate analyses, as well as linear and nonlinear regression models. RESULTS: The prevalence of overweight and obesity was 15.45% and 19.76%, respectively. There was a significant negative correlation between breastfeeding duration and BMI in children and adolescents (ß = -0.025, 95% CI: -0.033, -0.005, P < 0.01). Among boys, the BMI in children and adolescences of those who have been breastfed for more than 12 months was significantly lower than that of others whose breastfeeding duration was less than 12 months (ß = -0.440, 95%CI -0.655, -0.224, P < 0.01). Breastfeeding has a particularly positive effect on the prevalence of obesity in boys aged 9 to 11 years (OR = 0.978, 95% CI: 0.958,0.999, P < 0.05). CONCLUSION: Breastfeeding can significantly reduce the prevalence of overweight and obesity among children and adolescents aged 6 to 16 years. Those who were breastfed for more than 12 months had a lower risk of developing overweight and obesity, especially boys between the ages of 9 and 11.
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Sobrepeso , Obesidade Infantil , Adolescente , Índice de Massa Corporal , Aleitamento Materno , Criança , China/epidemiologia , Estudos Transversais , Feminino , Humanos , Masculino , Sobrepeso/epidemiologia , Sobrepeso/etiologia , Obesidade Infantil/epidemiologia , Obesidade Infantil/etiologia , PrevalênciaRESUMO
The aim of this study was to solve the frequently occurring rotor-stator rub-impact fault in aero-engines without causing a significant reduction in efficiency. We proposed a fault mitigation scheme, using shape memory alloy (SMA) wire, whereby the tip clearance between the rotor and the stator is adjusted. In this scheme, an acoustic emission (AE) sensor is utilized to monitor the rub-impact fault. An active control actuator is designed with pre-strained two-way SMA wires, driven by an electric current via an Arduino control board, to mitigate the rub-impact fault once it occurs. In order to investigate the feasibility of the proposed scheme, a series of tests on the material properties of NiTi wires, including heating response rate, ultimate strain, free recovery rate, and restoring force, were carried out. A prototype of the actuator was designed, manufactured, and tested under various conditions. The experimental result verifies that the proposed scheme has the potential to mitigate or eliminate the rotor-stator rub-impact fault in aero-engines.
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Photodynamic bonds are stable in the dark and can reversibly dissociate/form under light irradiation. Photodynamic bonds are promising building blocks for responsive or healable materials, photoactivated drugs, nanocarriers, extracellular matrices, etc. However, reactive intermediates from photodynamic bonds usually lead to side reactions, which limit the use of photodynamic bonds. Here, we report that the Ru-Se coordination bond is a new photodynamic bond that reversibly dissociates under mild visible-light-irradiation conditions. We observed that Ru-Se bonds form via the coordination of a selenoether ligand with [Ru(tpy)(biq)(H2O)]Cl2 (tpy = 2,2':6',2â³-terpyridine, biq = 2,2'-biquinoline) in the dark, while the Ru-Se bond reversibly dissociates under visible-light irradiation. No side reaction is detected in the formation and dissociation of Ru-Se bonds. To demonstrate that the Ru-Se bond is applicable to different operating environments, we prepared photoresponsive amphiphiles, surfaces, and polymer gels using Ru-Se bonds. The amphiphiles with Ru-Se bonds showed reversible morphological transitions between spherical micelles and bowl-shaped assemblies for dark/light irradiation cycles. The surfaces modified with Ru-Se-bond-containing compounds showed photoswitchable wettability. Polymer gels with Ru-Se cross-links underwent photoinduced reversible sol-gel transitions, which can be used for reshaping and healing. Our work demonstrates that the Ru-Se bond is a new type of dynamic bond, which can be used for constructing responsive, reprocessable, switchable, and healable materials that work in a variety of environments.
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In this work, a novel convenient colorimetric method for sensitive detection of thiocyanate (SCN-) has been developed based on its suppression of the oxidase-like activity of palladium square nanoplates on reduced graphene oxide (Pd SP@rGO). SCN- can be adsorbed onto the surface of Pd SP@rGO via binding with Pd atoms and blocks the active sites that mimic oxidase, thus inhibiting the corresponding chromogenic reaction of 3,3',5,5'-tetramethylbenzidine, which has been comprehensively revealed by the UV-vis spectra and X-ray photoelectron spectra. The color fading exhibits SCN- concentration-dependent behavior and can be easily recorded by either UV-vis spectroscopy or naked-eye observation. Therefore, both quantitative detection via measurement of the decrease in absorbance and visual detection of SCN- can be achieved. Owing to the intrinsic amplification of signals by the oxidase-like activity of Pd SP@rGO without resorting to unstable and destructive H2O2, this assay is straightforward, robust and sensitive enough for the detection of SCN- in real samples. Furthermore, an "INH" logic gate is rationally constructed based on the proposed colorimetric SCN- sensor.
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Paládio , Tiocianatos , Domínio Catalítico , Colorimetria , Peróxido de Hidrogênio , OxirredutasesRESUMO
To understand the characteristics and influencing factors related to cluster infections in Jiangsu Province, China, we investigated case reports to explore transmission dynamics and influencing factors of scales of cluster infection. The effectiveness of interventions was assessed by changes in the time-dependent reproductive number (Rt). From 25th January to 29th February, Jiangsu Province reported a total of 134 clusters involving 617 cases. Household clusters accounted for 79.85% of the total. The time interval from onset to report of index cases was 8 days, which was longer than that of secondary cases (4 days) (χ2 = 22.763, P < 0.001) and had a relationship with the number of secondary cases (the correlation coefficient (r) = 0.193, P = 0.040). The average interval from onset to report was different between family cluster cases (4 days) and community cluster cases (7 days) (χ2 = 28.072, P < 0.001). The average time interval from onset to isolation of patients with secondary infection (5 days) was longer than that of patients without secondary infection (3 days) (F = 9.761, P = 0.002). Asymptomatic patients and non-familial clusters had impacts on the size of the clusters. The average reduction in the Rt value in family clusters (26.00%, 0.26 ± 0.22) was lower than that in other clusters (37.00%, 0.37 ± 0.26) (F = 4.400, P = 0.039). Early detection of asymptomatic patients and early reports of non-family clusters can effectively weaken cluster infections.
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COVID-19/epidemiologia , Coinfecção/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , COVID-19/virologia , Criança , Pré-Escolar , China/epidemiologia , Análise por Conglomerados , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
Enzyme-mimetic properties of nanomaterials can be efficiently tuned by controlling their size, composition, and structure. Here, ultrathin PdCu alloy nanosheet-assembled three-dimensional (3D) nanoflowers (Pd1Cux NAFs) with tunable surface composition are obtained via a generalized strategy. In presence of H2O2, the as-synthesized Pd1Cux NAFs can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to the oxidized form of TMB (oxTMB) with a characteristic absorption peak at 652 nm. Interestingly, Pd1Cux NAFs show obviously composition-dependent peroxidase-like catalytic activities because of the synergistic interaction of nanoalloy. Additionally, different from 2D Pd nanosheets, the distinctive 3D superstructures are featured with rich approachable sites and proper layer spacing, which are in favor of fast mass transport and electron transfers during the catalytic process. Among the studied Pd1Cux NAFs, the Pd1Cu1.7 NAFs show the highest enzyme-like activities and can be successfully applied for the colorimetric detection of glucose with a low detection limit of 2.93 ± 0.53 µM. This work provides an efficient avenue to fabricate PdCu NAF nanozymes in biosensing toward glucose detection. Two-dimensional (2D) PdCu ultrathin nanosheet-assembled 3D nanoflowers (Pd1Cux NAFs) with tunable surface composition exhibit substantially enhanced intrinsic peroxidase-like catalytic activities. The Pd1Cu1.7 NAFs are successfully used as peroxidase mimic catalyst for the colorimetric detection of glucose with low detection limit of 2.93 µM.
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Ligas/química , Glicemia/análise , Nanoestruturas/química , Benzidinas/química , Técnicas Biossensoriais/métodos , Glicemia/química , Catálise , Compostos Cromogênicos/química , Colorimetria/métodos , Cobre/química , Humanos , Peróxido de Hidrogênio/análise , Peróxido de Hidrogênio/química , Cinética , Limite de Detecção , Oxirredução , Paládio/químicaRESUMO
A convenient and sensitive colorimetric assay for acetylcholinesterase (AChE) and its inhibitor has been designed based on the oxidase-like activity of {100}-faceted Pd square nanoplates which are grown in situ on reduced graphene oxide (PdSP@rGO). PdSP@rGO can effectively catalyze the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) without the assistance of H2O2 to generate blue oxidized TMB (oxTMB) with a characteristic absorption peak at 652 nm. In the presence of AChE, acetylthiocholine (ATCh), a typical AChE substrate, is hydrolyzed to thiocholine (TCh). The generated TCh can effectively inhibit the PdSP@rGO-triggered chromogenic reaction of TMB via cheating with Pd, resulting in color fading and decrease in absorbance. Thus, a sensitive probe for AChE activity is constructed with a working range of 0.25-5 mU mL-1 and a limit of detection (LOD) of 0.0625 mU mL-1. Furthermore, because of the inhibition effect of tacrine on AChE, tacrine is also detected through the colorimetric AChE assay system within the concentrations range 0.025-0.4 µM with a LOD of 0.00229 µM. Hence, a rapid and facile colorimetric procedure to sensitively detect AChE and its inhibitor can be anticipated through modulating the oxidase-like activity of PdSP@rGO. Colorimetric method for detection of AChE and its inhibitor is established by modulating the oxidase mimetic activity of {100}-faceted Pd square nanoplates on reduced graphene oxide (PdSP@rGO).