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Colloidal quantum dots (QDs) are excellent luminescent nanomaterials for many optoelectronic applications. However, photoluminescence blinking has limited their practical use. Coupling QDs to plasmonic nanostructures shows potential in suppressing blinking. However, the underlying mechanism remains unclear and debated, hampering the development of bright nonblinking dots. Here, by deterministically coupling a QD to a plasmonic nanocavity, we clarify the mechanism and demonstrate unprecedented single-QD brightness. In particular, we report for the first time that a blinking QD could obtain nonblinking photoluminescence with a blinking lifetime through coupling to the nanocavity. We show that the plasmon-enhanced radiative decay outcompetes the nonradiative Auger process, enabling similar quantum yields for charged and neutral excitons in the same dot. Meanwhile, we demonstrate a record photon detection rate of 17 MHz from a colloidal QD, indicating an experimental photon generation rate of more than 500 MHz. These findings pave the way for ultrabright nonblinking QDs, benefiting diverse QD-based applications.
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BACKGROUND: Salt sensitivity of blood pressure (SSBP) is an intermediate phenotype of hypertension and is a predictor of long-term cardiovascular events and death. However, the genetic structures of SSBP are uncertain, and it is difficult to precisely diagnose SSBP in population. So, we aimed to identify genes related to susceptibility to the SSBP, construct a risk evaluation model, and explore the potential functions of these genes. METHODS AND RESULTS: A genome-wide association study of the systemic epidemiology of salt sensitivity (EpiSS) cohort was performed to obtain summary statistics for SSBP. Then, we conducted a transcriptome-wide association study (TWAS) of 12 tissues using FUSION software to predict the genes associated with SSBP and verified the genes with an mRNA microarray. The potential roles of the genes were explored. Risk evaluation models of SSBP were constructed based on the serial P value thresholds of polygenetic risk scores (PRSs), polygenic transcriptome risk scores (PTRSs) and their combinations of the identified genes and genetic variants from the TWAS. The TWAS revealed that 2605 genes were significantly associated with SSBP. Among these genes, 69 were differentially expressed according to the microarray analysis. The functional analysis showed that the genes identified in the TWAS were enriched in metabolic process pathways. The PRSs were correlated with PTRSs in the heart atrial appendage, adrenal gland, EBV-transformed lymphocytes, pituitary, artery coronary, artery tibial and whole blood. Multiple logistic regression models revealed that a PRS of P < 0.05 had the best predictive ability compared with other PRSs and PTRSs. The combinations of PRSs and PTRSs did not significantly increase the prediction accuracy of SSBP in the training and validation datasets. CONCLUSIONS: Several known and novel susceptibility genes for SSBP were identified via multitissue TWAS analysis. The risk evaluation model constructed with the PRS of susceptibility genes showed better diagnostic performance than the transcript levels, which could be applied to screen for SSBP high-risk individuals.
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Presión Sanguínea , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Humanos , Presión Sanguínea/genética , Perfilación de la Expresión Génica , Hipertensión/genética , Transcriptoma , Polimorfismo de Nucleótido Simple , Masculino , Medición de Riesgo , Femenino , Cloruro de Sodio Dietético/efectos adversosRESUMEN
Electron-phonon (e-p) coupling plays a crucial role in various physical phenomena, and regulation of e-p coupling is vital for the exploration and design of high-performance materials. However, the current research on this topic lacks accurate quantification, hindering further understanding of the underlying physical processes and its applications. In this work, we demonstrate quantitative regulation of e-p coupling, by pressure engineering andin-situspectroscopy. We successfully observe both a distinct vibrational mode and a strong Stokes shift in layered CrBr3, which are clear signatures of e-p coupling. This allows us to achieve precise quantification of the Huang-Rhys factorSat the actual sample temperature, thus accurately determining the e-p coupling strength. We further reveal that pressure efficiently regulates the e-p coupling in CrBr3, evidenced by a remarkable 40% increase inSvalue. Our results offer an approach for quantifying and modulating e-p coupling, which can be leveraged for exploring and designing functional materials with targeted e-p coupling strengths.
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Methionine adenosyltransferase 2 A (MAT2A) mediates the synthesis of methyl donor S-Adenosylmethionine (SAM), providing raw materials for methylation reactions in cells. MAT2A inhibitors are currently used for the treatment of tumors with methylthioadenosine phosphorylase (MTAP) deficiency in clinical research. Methyltransferase like 3 (METTL3) catalyzes N6-methyladenosine (m6A) modification of mRNA in mammalian cells using SAM as the substrate which has been shown to affect the tumorigenesis of non-small cell lung cancer (NSCLC) from multiple perspectives. MAT2A-induced SAM depletion may have the potential to inhibit the methyl transfer function of METTL3. Therefore, in order to expand the applicability of inhibitors, improve anti-tumor effects and reduce toxicity, the combinational effect of MAT2A inhibitor AG-270 and METTL3 inhibitor STM2457 was evaluated in NSCLC. The results showed that this combination induced cell apoptosis rather than cell cycle arrest, which was non-tissue-specific and was independent of MTAP expression status, resulting in a significant synergistic anti-tumor effect. We further elucidated that the combination-induced enhanced apoptosis was associated with the decreased m6A level, leading to downregulation of PI3K/AKT protein, ultimately activating the apoptosis-related proteins. Unexpectedly, although combination therapy resulted in metabolic recombination, no significant change in methionine metabolic metabolites was found. More importantly, the combination also exerted synergistic effects in vivo. In summary, the combination of MAT2A inhibitor and METTL3 inhibitor showed synergistic effects both in vivo and in vitro, which laid a theoretical foundation for expanding the clinical application research of the two types of drugs.
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Apoptosis , Carcinoma de Pulmón de Células no Pequeñas , Sinergismo Farmacológico , Neoplasias Pulmonares , Metionina Adenosiltransferasa , Metiltransferasas , Animales , Humanos , Ratones , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/patología , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Línea Celular Tumoral , Inhibidores Enzimáticos/farmacología , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/metabolismo , Metionina Adenosiltransferasa/metabolismo , Metionina Adenosiltransferasa/antagonistas & inhibidores , Metionina Adenosiltransferasa/genética , Metiltransferasas/metabolismo , Metiltransferasas/antagonistas & inhibidores , Ratones Endogámicos BALB C , Ratones Desnudos , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
BACKGROUND: Sjögren's Syndrome (SS) is a rare chronic autoimmune disorder primarily affecting adult females, characterized by chronic inflammation and salivary and lacrimal gland dysfunction. It is often associated with systemic lupus erythematosus, rheumatoid arthritis and kidney disease, which can lead to increased mortality. Early diagnosis is critical, but traditional methods for diagnosing SS, mainly through histopathological evaluation of salivary gland tissue, have limitations. METHODS: The study used 100 labial gland biopsy, creating whole-slide images (WSIs) for analysis. The proposed model, named Cell-tissue-graph-based pathological image analysis model (CTG-PAM) and based on graph theory, characterizes single-cell feature, cell-cell feature, and cell-tissue feature. Building upon these features, CTG-PAM achieves cellular-level classification, enabling lymphocyte recognition. Furthermore, it leverages connected component analysis techniques in the cell graph structure to perform SS diagnosis based on lymphocyte counts. FINDINGS: CTG-PAM outperforms traditional deep learning methods in diagnosing SS. Its area under the receiver operating characteristic curve (AUC) is 1.0 for the internal validation dataset and 0.8035 for the external test dataset. This indicates high accuracy. The sensitivity of CTG-PAM for the external dataset is 98.21%, while the accuracy is 93.75%. In comparison, the sensitivity and accuracy for traditional deep learning methods (ResNet-50) are lower. The study also shows that CTG-PAM's diagnostic accuracy is closer to skilled pathologists compared to beginners. INTERPRETATION: Our findings indicate that CTG-PAM is a reliable method for diagnosing SS. Additionally, CTG-PAM shows promise in enhancing the prognosis of SS patients and holds significant potential for the differential diagnosis of both non-neoplastic and neoplastic diseases. The AI model potentially extends its application to diagnosing immune cells in tumor microenvironments.
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Síndrome de Sjögren , Síndrome de Sjögren/diagnóstico , Síndrome de Sjögren/patología , Humanos , Femenino , Estudios de Cohortes , Curva ROC , Procesamiento de Imagen Asistido por Computador/métodos , Persona de Mediana Edad , Aprendizaje Profundo , Área Bajo la Curva , Adulto , AutomatizaciónRESUMEN
We demonstrated a high-performance partially corrugated waveguide distributed feedback (PCW-DFB) laser with high output power, low relative intensity noise (RIN) and narrow linewidth. By introducing offset quantum-well structure that provides enough threshold gain difference for single transverse mode operation, the laser can achieve single mode behavior with an 8-µm-wide ridge waveguide. The laser has been designed by the simulation model based on the coupled wave equations, and the fabricated PCW-DFB laser with the cavity length of 1.3 mm exhibited an output power higher than 190â mW. Stable single mode characteristics have been achieved with a side-mode suppression-ratio (SMSR) over 55â dB. The RIN was less than -160.5â dB/Hz at an injection current of 470â mA, and the linewidth reached 45 kHz.
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Extracellular vesicles (EVs), secreted by most cells, act as natural cell-derived carriers for delivering proteins, nucleic acids, and organelles between cells. Mitochondria are highly dynamic organelles responsible for energy production and cellular physiological processes. Recent evidence has highlighted the pivotal role of EVs in intercellular mitochondrial content transfer, including mitochondrial DNA (mtDNA), proteins, and intact mitochondria. Intriguingly, mitochondria are crucial mediators of EVs release, suggesting an interplay between EVs and mitochondria and their potential implications in physiology and pathology. However, in this expanding field, much remains unknown regarding the function and mechanism of crosstalk between EVs and mitochondria and the transport of mitochondrial EVs. Herein, we shed light on the physiological and pathological functions of EVs and mitochondria, potential mechanisms underlying their interactions, delivery of mitochondria-rich EVs, and their clinical applications in regenerative medicine.
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Vesículas Extracelulares , Mitocondrias , Medicina Regenerativa , Humanos , Vesículas Extracelulares/metabolismo , Medicina Regenerativa/métodos , Mitocondrias/metabolismo , AnimalesRESUMEN
BACKGROUND: Radiotherapy (RT) can drive cancer cells to enter a state of cellular senescence in which cells can secrete senescence-associated secretory phenotype (SASP) and produce small extracellular vesicles (sEVs) to interact with cells in the tumor microenvironment (TME). Tumor-derived sEVs that are taken up by recipient cells contribute to cancer cell metabolic plasticity, resistance to anticancer therapy, and adaptation to the TME. However, how radiation-induced sEVs support oral squamous cell carcinoma (OSCC) progression remains unclear. METHODS: Beta-galactosidase staining and SASP mRNA expression analysis were used to evaluate the senescence-associated activity of OSCC cells after irradiation. Nanoparticle tracking analysis was performed to identify radiation-induced sEVs. Liquid chromatography-tandem mass spectrometry (LC-MS) was used to explore changes in the levels of proteins in radiation-induced sEVs. Cell Counting Kit-8 and colony formation assays were performed to investigate the function of radiation-induced SASP and sEVs in vitro. A xenograft tumor model was established to investigate the functions of radiation-induced sEVs and V-9302 in vivo as well as the underlying mechanisms. Bioinformatics analysis was performed to determine the relationship between glutamine metabolism and OSCC recurrence. RESULTS: We determined that the radiation-induced SASP triggered OSCC cell proliferation. Additionally, radiation-induced sEVs exacerbated OSCC cell malignancy. LC-MS/MS and bioinformatics analyses revealed that SLC1A5, which is a cellular receptor that participates in glutamine uptake, was significantly enriched in radiation-induced sEVs. In vitro and in vivo, inhibiting SLC1A5 could block the oncogenic effects of radiation-induced sEVs in OSCC. CONCLUSION: Radiation-induced sEVs might promote the proliferation of unirradiated cancer cells by enhancing glutamine metabolism; this might be a novel molecular mechanism underlying radiation resistance in OSCC patients.
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Carcinoma de Células Escamosas , Progresión de la Enfermedad , Exosomas , Glutamina , Neoplasias de la Boca , Glutamina/metabolismo , Humanos , Neoplasias de la Boca/radioterapia , Neoplasias de la Boca/metabolismo , Neoplasias de la Boca/patología , Carcinoma de Células Escamosas/radioterapia , Carcinoma de Células Escamosas/metabolismo , Animales , Exosomas/metabolismo , Línea Celular Tumoral , Microambiente Tumoral , Ratones , Antígenos de Histocompatibilidad Menor/metabolismo , Ratones Desnudos , Senescencia Celular , Ratones Endogámicos BALB C , Sistema de Transporte de Aminoácidos A/metabolismo , Sistema de Transporte de Aminoácidos ASC/metabolismoRESUMEN
Investigations of two-dimensional transition-metal chalcogenides (TMCs) have recently revealed interesting physical phenomena, including the quantum spin Hall effect1,2, valley polarization3,4 and two-dimensional superconductivity 5 , suggesting potential applications for functional devices6-10. However, of the numerous compounds available, only a handful, such as Mo- and W-based TMCs, have been synthesized, typically via sulfurization11-15, selenization16,17 and tellurization 18 of metals and metal compounds. Many TMCs are difficult to produce because of the high melting points of their metal and metal oxide precursors. Molten-salt-assisted methods have been used to produce ceramic powders at relatively low temperature 19 and this approach 20 was recently employed to facilitate the growth of monolayer WS2 and WSe2. Here we demonstrate that molten-salt-assisted chemical vapour deposition can be broadly applied for the synthesis of a wide variety of two-dimensional (atomically thin) TMCs. We synthesized 47 compounds, including 32 binary compounds (based on the transition metals Ti, Zr, Hf, V, Nb, Ta, Mo, W, Re, Pt, Pd and Fe), 13 alloys (including 11 ternary, one quaternary and one quinary), and two heterostructured compounds. We elaborate how the salt decreases the melting point of the reactants and facilitates the formation of intermediate products, increasing the overall reaction rate. Most of the synthesized materials in our library are useful, as supported by evidence of superconductivity in our monolayer NbSe2 and MoTe2 samples21,22 and of high mobilities in MoS2 and ReS2. Although the quality of some of the materials still requires development, our work opens up opportunities for studying the properties and potential application of a wide variety of two-dimensional TMCs.
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Quick differentiation of current circulating variants and the emerging recombinant variants of SARS-CoV-2 is essential to monitor their transmissions. However, the widely applied gene sequencing method is time-consuming and costly especially when facing recombinant variants, because a large part or whole genome sequencing is required. Allele-specific reverse transcriptase real time RT-PCR (RT-qPCR) represents a quick and cost-effective method for SNP (single nucleotide polymorphism) genotyping and has been successfully applied for SARS-CoV-2 variant screening. In the present study, we developed a panel of 5 multiplex allele-specific RT-qPCR assays targeting 20 key mutations for quick differentiation of the Omicron subvariants (BA.1 to BA.5 and their descendants) and the recombinant variants (XBB.1 and XBB.1.5). Two parallel multiplex RT-qPCR reactions were designed to separately target the prototype allele and the mutated allele of each mutation in the allele-specific RT-qPCR assay. Optimal annealing temperatures, primer and probe dosage, and time for annealing/extension for each reaction were determined by multi-factor and multi-level orthogonal test. The variation of Cp (crossing point) values (ΔCp) between the two multiplex RT-qPCR reactions was applied to determine if a mutation occurs or not. SARS-CoV-2 subvariants and related recombinant variants were differentiated by their unique mutation patterns. The developed multiplex allele-specific RT-qPCR assays exhibited excellent analytical sensitivities (with limits of detection (LoDs) of 1.47-18.52 copies per reaction), wide linear detection ranges (109-100 copies per reaction), good amplification efficiencies (88.25 to 110.68%), excellent reproducibility (coefficient of variations (CVs) < 5% in both intra-assay and inter-assay tests), and good clinical performances (99.5-100% consistencies with Sanger sequencing). The developed multiplex allele-specific RT-qPCR assays in the present study provide an alternative tool for quick differentiation of the SARS-CoV-2 Omicron subvariants and their recombinant variants. KEY POINTS: ⢠A panel of five multiplex allele-specific RT-qPCR assays for quick differentiation of 11 SARS-CoV-2 Omicron subvariants (BA.1, BA.2, BA.4, BA.5, and their descendants) and 2 recombinant variants (XBB.1 and XBB.1.5). ⢠The developed assays exhibited good analytical sensitivities and reproducibility, wide linear detection ranges, and good clinical performances, providing an alternative tool for quick differentiation of the SARS-CoV-2 Omicron subvariants and their recombinant variants.
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COVID-19 , Humanos , Alelos , COVID-19/diagnóstico , Reproducibilidad de los Resultados , SARS-CoV-2/genéticaRESUMEN
INTRODUCTION AND OBJECTIVES: Seroclearance of hepatitis B e antigen (HBeAg) is an important treatment goal for patients with chronic hepatitis B (CHB). This study developed a nomogram for predicting HBeAg seroclearance in CHB patients treated with nucleos(t)ide analogues (NAs). PATIENTS AND METHODS: Five hundred and sixty-nine CHB patients treated with NAs from two institutions between July 2016 to November 2021 were retrospectively included. One institution served as the training set (n = 374) and the other as the external validation set (n = 195). A predictive nomogram was established based on cox regression analysis. RESULTS: The overall HBeAg seroclearance rates were 27.3 and 21.5 % after the median follow-up of 100.2 weeks and 65.1 weeks in the training set and validation set, respectively. In the training set, baseline aspartate aminotransferase, gamma-glutamyl transpeptidase, HBeAg, and hepatitis B core antibody levels were independently associated with HBeAg seroclearance and were used to establish the HBEAg SeroClearance (ESC)-nomogram. The calibration curve revealed that the ESC-nomogram had a good agreement with actual observation. The ESC-nomogram showed relatively high accuracy for predicting 48 weeks, 96 weeks, and 144 weeks of HBeAg seroclearance in the training set (AUCs: 0.782, 0.734 and 0.671) and validation set (AUCs: 0.699, 0.718 and 0.689). The patients with high ESC-nomogram scores (≥ 79.51) had significantly higher cumulative incidence of HBeAg seroclearance and seroconversion than patients with low scores (< 79.51) in both sets (P < 0.01). CONCLUSIONS: The novel ESC-nomogram showed good performance for predicting antiviral efficacy in HBeAg-positive CHB patients with NAs treatment.
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Hepatitis B Crónica , Humanos , Hepatitis B Crónica/diagnóstico , Hepatitis B Crónica/tratamiento farmacológico , Hepatitis B Crónica/complicaciones , Antígenos e de la Hepatitis B , Antivirales/uso terapéutico , Estudios Retrospectivos , Nomogramas , Virus de la Hepatitis B , Antígenos de Superficie de la Hepatitis B , Resultado del Tratamiento , ADN ViralRESUMEN
This case demonstrated intraoperative real-time transesophageal echocardiographic monitoring in minimally invasive small-incision Off-pump ligation of a coronary artery fistula,demonstrating the importance of esophageal echocardiography in surgical monitoring.
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Fístula Arterio-Arterial , Enfermedad de la Arteria Coronaria , Humanos , Ecocardiografía Transesofágica , Fístula Arterio-Arterial/diagnóstico por imagen , Fístula Arterio-Arterial/cirugía , Arteria Pulmonar/diagnóstico por imagen , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Enfermedad de la Arteria Coronaria/cirugíaRESUMEN
Aortic root pseudoaneurysm is a devastating complication post aortic valve replacement with a high mortality rate. And dissecting aneurysm into the interventricular septum is a rare variant of aortic root pseudoaneurysm, which is scarcely reported. Multimodal imaging is of great value in its diagnosis and differential diagnosis.
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Aneurisma Falso , Disección Aórtica , Imagen Multimodal , Tabique Interventricular , Humanos , Aneurisma Falso/diagnóstico por imagen , Aneurisma Falso/complicaciones , Imagen Multimodal/métodos , Tabique Interventricular/diagnóstico por imagen , Disección Aórtica/complicaciones , Disección Aórtica/diagnóstico por imagen , Disección Aórtica/diagnóstico , Aneurisma Cardíaco/etiología , Aneurisma Cardíaco/diagnóstico por imagen , Aneurisma Cardíaco/complicaciones , Diagnóstico Diferencial , Masculino , Válvula Aórtica/diagnóstico por imagen , Ecocardiografía/métodos , Implantación de Prótesis de Válvulas CardíacasRESUMEN
This article reports a case of LV outflow obstruction caused by abnormalities of the anterior leaflet connection of the mitral papillary muscle, aiming to highlight the importance of combined multimodal imaging in the differential diagnosis of the etiology of LV outflow obstruction.
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Cardiomiopatía Hipertrófica , Obstrucción del Flujo de Salida Ventricular Izquierda , Obstrucción del Flujo Ventricular Externo , Humanos , Músculos Papilares/diagnóstico por imagen , Obstrucción del Flujo Ventricular Externo/diagnóstico por imagen , Obstrucción del Flujo Ventricular Externo/etiología , Válvula Mitral/diagnóstico por imagen , Imagen Multimodal/efectos adversos , Cardiomiopatía Hipertrófica/complicacionesRESUMEN
Transesophageal echocardiography (TEE) shows pericardial effusion and a gap between the left atrium and the aortic sinus by atrial septal defect occluder.
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Cateterismo Cardíaco , Taponamiento Cardíaco , Ecocardiografía Transesofágica , Defectos del Tabique Interatrial , Dispositivo Oclusor Septal , Humanos , Defectos del Tabique Interatrial/cirugía , Defectos del Tabique Interatrial/diagnóstico por imagen , Taponamiento Cardíaco/etiología , Taponamiento Cardíaco/diagnóstico por imagen , Ecocardiografía Transesofágica/métodos , Cateterismo Cardíaco/métodos , Femenino , Complicaciones Posoperatorias/diagnóstico por imagen , Masculino , Derrame Pericárdico/diagnóstico por imagen , Derrame Pericárdico/etiologíaRESUMEN
The global pandemic of coronavirus disease 2019 (COVID-19) poses a serious threat to human health, leading to a relatively high mortality in patients with severe or critical conditions in particular. Hyperglycemia is one of the high-risk factors for poor prognosis in these patients. Patients with COVID-19 are more likely to develop hyperglycemia, regardless of whether there is a previous history of diabetes mellitus. Glucocorticoid therapy is an important part of the anti-inflammatory regimen for COVID-19. However, the use of glucocorticoid significantly increases the occurrence of hyperglycemic events in COVID-19 patients, ultimately leading to poor prognosis. Timely monitoring of blood glucose and early intervention for hyperglycemia contribute to the improvement in the outcome of COVID-19 patients. In this paper, we comprehensively reviewed the potential mechanisms of COVID-19 and concomitant hyperglycemia. We reviewed the latest findings on the blood glucose management strategies for COVID-19 patients with concomitant hyperglycemia, aiming to optimize the management of hyperglycemia in COVID-19 patients and improve the outcome of the disease.
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COVID-19 , Hiperglucemia , Humanos , Glucemia , COVID-19/complicaciones , Glucocorticoides , Hiperglucemia/complicacionesRESUMEN
Two-dimensional (2D) layered materials can stack into new material systems, with van der Waals (vdW) interaction between the adjacent constituent layers. This stacking process of 2D atomic layers creates a new degree of freedom-interlayer interface between two adjacent layers-that can be independently studied and tuned from the intralayer degree of freedom. In such heterostructures (HSs), the physical properties are largely determined by the vdW interaction between the individual layers,i.e.interlayer coupling, which can be effectively tuned by a number of means. In this review, we summarize and discuss a number of such approaches, including stacking order, electric field, intercalation, and pressure, with both their experimental demonstrations and theoretical predictions. A comprehensive overview of the modulation on structural, optical, electrical, and magnetic properties by these four approaches are also presented. We conclude this review by discussing several prospective research directions in 2D HSs field, including fundamental physics study, property tuning techniques, and future applications.
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Physiological function analysis of terminal deoxynucleotidyl transferase (TdT) in clinical medicine and hematopathology highlights its significance to be extensively utilized as a diagnostic biomarker for leukemia diagnosis. Herein, taking advantage of the spatial-confinement effect on a three-dimensional (3D) DNA nanoarchitecture, we reported a target-triggered intramolecular accelerated molecular beacon (MB) assembly for rapid and real-time analysis of TdT activity. In this strategy, the 3D DNA nanoarchitecture is first engineered via a cross-linking network hybridization chain reaction (HCR). A number of MBs, which were designed with a polythymine (poly-T) loop, were then conjugated on the scaffold DNA nanoarchitecture, allowing the obtained MB-DNA nanoarchitecture to contain lots of free 3'-hydroxyl (OH) termini inside or outside the super DNA nanostructure. Moreover, the distance between different MBs is closed, and the local concentration of MB is significantly improved owing to the confinement of MBs on this DNA nanoarchitecture. Once encountered with target TdT, the free -OH groups can be recognized by TdT immediately to catalyze the template-independent incorporation of adenine nucleotides, which results in the generation of multiple poly-A chains that rapidly react with many MBs via an intramolecular accelerated assembly process. The time-dependent substantial enhancement of the fluorescence from MBs can thus be applied for robustly analyzing TdT. Our observations suggest that the DNA nanostructure-based spatial confinement effect enables a high molecular collision frequency to accelerate the reaction kinetics, and the super DNA nanoarchitecture exhibits a better nuclease resistance to maintain signal stability. With these advantages, TdT can be rapidly detected with high sensitivity, specificity, and biostability.
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ADN Nucleotidilexotransferasa , ADN Polimerasa Dirigida por ADN , Nucleótidos de Adenina , Catálisis , ColorantesRESUMEN
Surface-enhanced Raman scattering (SERS) is regarded as the most direct and powerful tool to identify chemical fingerprints. However, current SERS substrate materials still face some critical challenges, including low molecular utilization efficiency and low selectivity. Herein, a novel oxygen vacancy heteropolyacidâH10Fe3Mo21O51 (HFMO)âis developed as a high-performance volume-enhanced Raman scattering (VERS)-active platform. Due to its merit of water solubility, HFMO forms a special coordination bond with the probe molecule at the molecular level, which allows its enhancing ability to be comparable to that of noble metals. An enhancement factor of 1.26 × 109 and a very low detection limit of 10-13 M for rhodamine 6G were obtained. A robust O-N coordination bond was formed between the anion of HFMO and the probe molecule, resulting in a special electron transfer path (Mo-O-N) with high selectivity, which is verified using X-ray photoelectron spectroscopy analysis and density functional theory calculations. That is to say, the proposed HFMO platform has excellent VERS enhancing effect, specifically for the molecules containing the imino group (e.g., methyl blue, detection limit: 10-11 M), offering the merits of high reproducibility and uniformity, high-temperature resistance, long-time laser irradiation, and strong acid resistance. Such an initial effort on the ionic type VERS platform may enable the further development of highly sensitive, highly selective, and water-soluble VERS technology.
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As an emerging two-dimensional semiconductor, rhenium disulfide (ReS2 ) is renowned for its strong in-plane anisotropy in electrical, optical, and thermal properties. In contrast to the electrical, optical, optoelectrical, and thermal anisotropies that are extensively studied in ReS2 , experimental characterization of mechanical properties has largely remained elusive. Here, it is demonstrated that the dynamic response in ReS2 nanomechanical resonators can be leveraged to unambiguously resolve such disputes. Using anisotropic modal analysis, the parameter space for ReS2 resonators in which mechanical anisotropy is best manifested in resonant responses is determined. By measuring their dynamic response in both spectral and spatial domains using resonant nanomechanical spectromicroscopy, it is clearly shown that ReS2 crystal is mechanically anisotropic. Through fitting numerical models to experimental results, it is quantitatively determined that the in-plane Young's moduli are 127 and 201 GPa along the two orthogonal mechanical axes. In combination with polarized reflectance measurements, it is shown that the mechanical soft axis aligns with the Re-Re chain in the ReS2 crystal. These results demonstrate that dynamic responses in nanomechanical devices can offer important insights into intrinsic properties in 2D crystals and provide design guidelines for future nanodevices with anisotropic resonant responses.