RESUMEN
A precise modulation of heterogeneous catalysts in structural and surface properties promises the development of more sustainable advanced oxidation water purification technologies. However, while catalysts with superior decontamination activity and selectivity are already achievable, maintaining a long-term service life of such materials remains challenging. Here, we propose a crystallinity engineering strategy to break the activity-stability tradeoff of metal oxides in Fenton-like catalysis. The amorphous/crystalline cobalt-manganese spinel oxide (A/C-CoMnOx) provided highly active, hydroxyl group-rich surface, with moderate peroxymonosulfate (PMS)-binding affinity and charge transfer energy and strong pollutant adsorption, to trigger concerted radical and nonradical reactions for efficient pollutant mineralization, thereby alleviating the catalyst passivation by oxidation intermediate accumulation. Meanwhile, the surface-confined reactions, benefited from the enhanced adsorption of pollutants at A/C interface, rendered the A/C-CoMnOx/PMS system ultrahigh PMS utilization efficiency (82.2%) and unprecedented decontamination activity (rate constant of 1.48 min-1) surpassing almost all the state-of-the-art heterogeneous Fenton-like catalysts. The superior cyclic stability and environmental robustness of the system for real water treatment was also demonstrated. Our work unveils a critical role of material crystallinity in modulating the Fenton-like catalytic activity and pathways of metal oxides, which fundamentally improves our understanding of the structure-activity-selectivity relationships of heterogeneous catalysts and may inspire material design for more sustainable water purification application and beyond.
RESUMEN
Cation exchange (CE) in metal oxides under mild conditions remains an imperative yet challenging goal to tailor their composition and enable practical applications. Herein, we first develop an amorphization-induced strategy to achieve room-temperature CE for universally synthesizing single-atom doped In2O3 nanosheets (NSs). Density functional theory (DFT) calculations elucidate that the abundant coordination-unsaturated sites present in a-In2O3 NSs are instrumental in surmounting the energy barriers of CE reactions. Empirically, a-In2O3 NSs as the host materials successfully undergo exchange with unary cations (Cu2+, Co2+, Mn2+, Ni2+), binary cations (Co2+Mn2+, Co2+Ni2+, Mn2+Ni2+), and ternary cations (Co2+Mn2+Ni2+). Impressively, high-loading single-atom doped (over 10 atom %) In2O3 NSs were obtained. Additionally, Cu/a-In2O3 NSs exhibit an excellent ethanol yield (798.7 µmol g-1 h-1) with a high selectivity of 99.5% for the CO2 photoreduction. This work offers a new approach to induce CE reactions in metal oxides under mild conditions and constructs scalable single-atom doped catalysts for critical applications.
RESUMEN
The protein nanoenvironment on the plasma membrane is intimately linked to cellular biological functions. Elucidation of the protein nanoenvironment contributes to understanding the pathological mechanism and discovery of disease biomarkers. However, methods enabling characterization of the protein nanoenvironment in the endogenous biological environment have been rarely developed. Toward this end, we created a nucleic acid tool called Apt-Gq/h for proximity labeling to decipher the endogenous protein nanoenvironment. Here, the aptamer acts as an anchor for binding the protein of interest (POI). The G-quadruplex/hemin complex induces proximity labeling of POI via catalyzing the conversion of inert small-molecule substrates into short-lived reactive species. The labeled proteins enable the subsequent affinity-based enrichment and proteomic analysis. We first characterized Apt-Gq/h-mediated POI labeling in vitro and tested its utility by interrogating the protein nanoenvironment of POI in living cells. Taking advantage of the nongenetic, multiple reaction sites, and rapid proximity labeling, Apt-Gq/h was further utilized to imaging the cell-cell connection and amplification detection of biomarkers in living cells and tissue sections. We believe that Apt-Gq/h will be a potential tool for basic science and clinical applications.
Asunto(s)
Ácidos Nucleicos , Hemina/química , Proteínas de la Membrana , Peroxidasa , ProteómicaRESUMEN
Tracking the spatial distribution of receptor tyrosine kinases in their native environment contributes to understanding the homeostatic or pathological states at a molecular level. Conjugation of DNA tags to a specific receptor is a powerful tool for monitoring receptor spatial distribution. However, long-term stable trafficking in live cells without interfering with the intrinsic receptor function remains a challenge. Here, we report a general DNA-templated glycan labeling strategy to track spatial distribution of a specific receptor in living cells. Different from existing target-selective covalent methods, the DNA tags were incorporated in glycan of a specific receptor via aptamer-assisted metabolic glycan labeling, thus resulting in minimal perturbation to the receptor's biological function. As proof of concept, covalent tagging of MET, HER2, and EGFR was achieved, and then the spatial distribution was successfully monitored, including homo-/heterodimerization and internalization. Overall, the proposed strategy will greatly aid in investigating receptor dynamics and is conducive to understanding their biological function in the native environment.
Asunto(s)
Proteínas Portadoras , Polisacáridos , DimerizaciónRESUMEN
BACKGROUND: Improved chondrogenic differentiation of mesenchymal stem cells (MSCs) by genetic regulation is a potential method for regenerating articular cartilage. MiR-127-5p has been reported to promote cartilage differentiation of rat bone marrow MSCs (rMSCs); however, the regulatory mechanisms underlying hypoxia-stimulated chondrogenic differentiation remain unknown. METHODS: rMSCs were induced to undergo chondrogenic differentiation under normoxic or hypoxic conditions. Expression of lncRNA DNM3OS, miR-127-5p, and GREM2 was detected by quantitative real-time PCR. Proteoglycans were detected by Alcian blue staining. Western blot assays were performed to examine the relative levels of GREM2 and chondrogenic differentiation related proteins. Luciferase reporter assays were performed to assess the association among DNM3OS, miR-127-5p, and GREM2. RESULTS: MiR-127-5p levels were upregulated, while DNM3OS and GREM2 levels were downregulated in rMSCs induced to undergo chondrogenic differentiation, and those changes were attenuated by hypoxic conditions (1% O2). Further in vitro experiments revealed that downregulation of miR-127-5p reduced the production of proteoglycans and expression of chondrogenic differentiation markers (COL1A1, COL2A1, SOX9, and ACAN) and osteo/chondrogenic markers (BMP-2, p-SMAD1/2). MiR-127-5p overexpression produced the opposite results in rMSCs induced to undergo chondrogenic differentiation under hypoxic conditions. GREM2 was found to be a direct target of miR-127-5p, which was suppressed in rMSCs undergoing chondrogenic differentiation. Moreover, DNM3OS could directly bind to miR-127-5p and inhibit chondrogenic differentiation of rMSCs via regulating GREM2. CONCLUSIONS: Our study revealed a novel molecular pathway (DNM3OS/miR-127-5p/GREM2) that may be involved in hypoxic chondrogenic differentiation.
Asunto(s)
Condrogénesis , Células Madre Mesenquimatosas/citología , MicroARNs/genética , Proteínas/genética , ARN Largo no Codificante/genética , Animales , Diferenciación Celular , Hipoxia de la Célula , Células Cultivadas , Regulación de la Expresión Génica , Masculino , Células Madre Mesenquimatosas/metabolismo , RatasRESUMEN
Coronavirus disease 2019 (COVID-19) outbreak, first reported in Wuhan, China, has rapidly swept around the world just within a month, causing global public health emergency. In diagnosis, chest computed tomography (CT) manifestations can supplement parts of limitations of real-time reverse transcription polymerase chain reaction (RT-PCR) assay. Based on a comprehensive literature review and the experience in the frontline, we aim to review the typical and relatively atypical CT manifestations with representative COVID-19 cases at our hospital, and hope to strengthen the recognition of these features with radiologists and help them make a quick and accurate diagnosis.Key Points⢠Ground glass opacities, consolidation, reticular pattern, and crazy paving pattern are typical CT manifestations of COVID-19.⢠Emerging atypical CT manifestations, including airway changes, pleural changes, fibrosis, nodules, etc., were demonstrated in COVID-19 patients.⢠CT manifestations may associate with the progression and prognosis of COVID-19.
Asunto(s)
Betacoronavirus , Infecciones por Coronavirus/diagnóstico por imagen , Neumonía Viral/diagnóstico por imagen , COVID-19 , Prueba de COVID-19 , Vacunas contra la COVID-19 , Técnicas de Laboratorio Clínico , Infecciones por Coronavirus/diagnóstico , Progresión de la Enfermedad , Humanos , Pandemias , Neumonía Viral/diagnóstico , Reacción en Cadena en Tiempo Real de la Polimerasa , SARS-CoV-2 , Tórax/diagnóstico por imagen , Tomografía Computarizada por Rayos XRESUMEN
Retinal diseases, such as age-related macular degeneration, diabetic retinopathy, and retinoblastoma, stand as the leading causes of irreversible vision impairment and blindness worldwide. Effectively administering drugs for retinal diseases poses a formidable challenge due to the presence of complex ocular barriers and elimination mechanisms. Over time, various approaches have been developed to fabricate drug delivery systems for improving retinal therapy including virus vectors, lipid nanoparticles, and polymers. However, conventional nanocarriers encounter issues related to the controllability, efficiency, and safety in the retina. Therefore, the development of smart nanocarriers for effective or more invasive long-term treatment remains a desirable goal. Recently, approaches have surfaced for the intelligent design of nanocarriers, leveraging specific responses to external or internal triggers and enabling multiple functions for retinal therapy such as topical administration, prolonged drug release, and site-specific drug delivery. This Review provides an overview of prevalent retinal pathologies and related pharmacotherapies to enhance the understanding of retinal diseases. It also surveys recent developments and strategies employed in the intelligent design of nanocarriers for retinal disease. Finally, the challenges of smart nanocarriers in potential clinical retinal therapeutic applications are discussed to inspire the next generation of smart nanocarriers.
Asunto(s)
Enfermedades de la Retina , Humanos , Enfermedades de la Retina/tratamiento farmacológico , Sistemas de Liberación de Medicamentos , Preparaciones FarmacéuticasRESUMEN
Integrating multiple functional components into vertically stacked heterostructures offers a prospective approach to manipulating the physicochemical properties of materials. The synthesis of vertically stacked heterogeneous noble metal oxides remains a challenge. Herein, we report a surface segregation approach to create vertically stacked amorphous Ir/Ru/Ir oxide nanosheets (NSs). Cross-sectional high-angle annular darkfield scanning transmission electron microscopy images demonstrate a three-layer heterostructure in the amorphous Ir/Ru/Ir oxide NSs, with IrOx layers located on the upper and lower surfaces, and a layer of RuOx sandwiched between the two IrOx layers. The vertically stacked heterostructure is a result of the diffusion of Ir atoms from the amorphous IrRuOx solid solution to the surface. The obtained A-Ir/Ru/Ir oxide NSs display an ultralow overpotential of 191 mV at 10 mA cm-2 toward acid oxygen evolution reaction and demonstrate excellent performance in a proton exchange membrane water electrolyzer, which requires only 1.63 V to achieve 1 A cm-2 at 60 °C, with virtually no activity decay observed after a 1300 h test.
RESUMEN
Selective photoreduction of carbon dioxide (CO2 ) into carbon-neutral fuels such as methane (CH4 ) is extremely desirable but remains a challenge since sluggish multiple proton-electron coupling transfer and various C1 intermediates are involved. Herein, a synergistic function between single Pd atoms (Pd1 ) and Pd nanoparticles (PdNPs ) on graphitic carbon nitride (C3 N4 ) for photocatalytic CO2 methanation is presented. The catalyst achieves a high selectivity of 97.8% for CH4 production with a yield of 20.3 µmol gcat. -1 h-1 in pure water. Mechanistic studies revealed that Pd1 sites activated CO2 , while PdNPs sites boosted water (H2 O) dissociation for increased H* coverage. The H* produced by PdNPs migrate to the Pd1 sites to promote multiple proton-electron coupling transfer via hydrogen spillover. Moreover, the adjacent Pd1 and PdNPs effectively stabilized intermediates such as *CHO, thereby favoring the pathway for CH4 production. This work provides a new perspective into the development of selective photocatalytic CO2 conversion through the artful design of synergistic catalytic sites.
RESUMEN
Supported single-atom catalysts (SACs), with the extremely homogenized active sites could achieve high hydrogenation selectivity toward one of the functional groups coexisting in the reactant molecule. However, as to the target group, the control of selective recognition and activation by SACs still remains a challenge. Herein, the phase engineering of the support is adopted to control the chemo-recognition behavior of SACs in selective hydrogenation. Single-atom Ru on amorphous porous ultrathin TiO2 nanosheets (Ru1/a-TiO2) is constructed, in which Ru is more positively charged than that in the crystalline counterpart (Ru1/c-TiO2). Moreover, in the nitro/vinyl selective hydrogenation process, Ru1/a-TiO2 shows superior nitro selectivity, opposite to the vinyl selectivity of Ru1/c-TiO2. Density functional theory calculations for single-atom Ru of different charge states show that the reactant adsorption configuration could be inverted in the amorphous TiO2, accounting for the chemo-recognition behavior controlled by the phase of support.
RESUMEN
An innovative g-C3N4 catalyzed surface-initiated photo atom transfer radical polymerization (SI-photoATRP) has been developed to construct MEDSAH zwitterionic polymer brushes on PVA hydrogel surface. g-C3N4 catalyzed SI-photoATRP is temporal and spatial control. As a heterogeneous reaction system, it can solve the catalyst residues problem. After grafting with MEDSAH, surface chemical composition and morphology of PVA-g-pMEDSAH hydrogel confirmed that MEDSAH was successfully grafted onto PVA hydrogel. Thermal property of PVA-g-pMEDSAH hydrogel decreased and hydrophilicity increased. No statistically significant differences between PVA and PVA-g-pMEDSAH were observed on mechanical properties. Cytotoxicity in vitro of PVA-g-pMEDSAH hydrogel could be considered as no cytotoxicity for L929 and NDHF cells. The antifouling properties of PVA-g-pMEDSAH hydrogel were significantly improved due to the enhancement of the surface hydration and steric repulsion effects caused by pMEDSAH polymer brushes. In addition, g-C3N4 is easier to modify to enhance the photocatalyst property. Thus, the heterogeneous reaction system of g-C3N4 catalyzed SI-photoATRP has huge potential applied in biomaterials surface modification.
Asunto(s)
Incrustaciones Biológicas , Hidrogeles , Incrustaciones Biológicas/prevención & control , Catálisis , Grafito , Compuestos de Nitrógeno , Polimerizacion , SemiconductoresRESUMEN
BACKGROUND: The therapeutic effects of adipose-derived mesenchymal stem cell (ADSC) transplantation have been demonstrated in several models of central nervous system (CNS) injury and are thought to involve the modulation of the inflammatory response. However, the exact underlying molecular mechanism is poorly understood. Activation of the Jagged1/Notch signaling pathway is thought to involve inflammatory and gliotic events in the CNS. Here, we elucidated the effect of ADSC transplantation on the inflammatory reaction after spinal cord injury (SCI) and the potential mechanism mediated by Jagged1/Notch signaling pathway suppression. METHODS: To evaluate the therapeutic effects of ADSC treatment and the potential inhibitory effects of ADSCs on Notch signaling, mice were subjected to contusion SCI, and GFP-labeled ADSCs were injected into the lesion site immediately after the injury. Locomotor function, spinal cord tissue morphology, and the levels of Notch-related proteins and proinflammatory transcripts were compared between groups. To validate the hypothesis that the therapeutic effects of ADSCs are partly due to Notch1 signaling inhibition, a Jagged1 small interfering RNA (siRNA) was injected into the spinal cord to knock down Jagged1/Notch signaling. Neuronal staining and analyses of microglia/macrophage activation and signaling pathways were performed. RESULTS: We demonstrated that ADSCs survived in the injured spinal cord for at least 28 days without differentiating into glial or neuronal elements. ADSC treatment resulted in significant downregulation of proinflammatory mediator expression and reduced ionized calcium-binding adapter molecule 1 (IBA1) and ED-1 staining in the injured spinal cord, eventually improving functional recovery. The augmentation of the Jagged1/Notch signaling pathway after SCI was suppressed by ADSC transplantation. The inhibition of the Jagged1/Notch signaling pathway by Jagged1 siRNA resulted in decreases in SCI-induced proinflammatory cytokines and the activation of microglia and an increase in the survival of neurons. Furthermore, Jagged1 knockdown suppressed the phosphorylation of JAK/STAT3 in astrocytes following SCI. CONCLUSION: The results of this study demonstrated that the therapeutic effects of ADSCs in SCI mice were partly due to Jagged1/Notch signaling pathway inhibition and a subsequent reduction in JAK/STAT3 phosphorylation in astrocytes.
Asunto(s)
Trasplante de Células Madre Mesenquimatosas , Células Madre Mesenquimatosas , Traumatismos de la Médula Espinal , Animales , Ratones , Receptores Notch/genética , Recuperación de la Función , Médula Espinal , Traumatismos de la Médula Espinal/terapiaRESUMEN
Multi-spectroscopy, such as FTIR, dispersive Raman spectroscopy and UV-Vis, was applied to characterize the blue gel pen inks on paper at the time in the present study. Twenty eight collected blue gel pens with different brands and serials were separated into four different classes by different absorptions or Raman shift. Composition changing of blue gel pen inks on paper during artificial ageing was studied via TD-MS as well. The advantage and disadvantage of this spectroscopy used in analyzing and identifying blue gel pen inks on paper, and the potential application in the research on relative and absolute ageing of documents were discussed.
RESUMEN
PURPOSE: This study compared the biomechanics of reinserted pedicle screws using the previous entry point and trajectory with those of correctly inserted pedicle screws. METHODS: The study used 18 lumbar vertebrae (L1-6) from three fresh calf spines to insert 6.5 × 40-mm pedicle screws. A control screw was inserted correctly along the axis of one pedicle, while an experimental screw was reinserted completely using the previous entry point and trajectory in the other pedicle. The experimental screw was removed after being completely inserted in group A and after 80% of the total trajectory inserted in group B. And the experimental screw was removed after 60% of the total trajectory was reached in group C. The biomechanical values of the pedicle screws were measured. RESULTS: There were no significant differences in pedicle screw axial pullout strength between reinserted screws and correct screws in the 3 groups (PA = 0.463, PB = 0.753, PC = 0.753). Stiffness measurement increased for the reinserted screw compared with that of the control screw. Fracturing was observed between the vertebral body and pedicle. CONCLUSION: Theoretically, a surgeon can remove the pedicle screw when necessary, inspect the trajectory, and reinsert the screw using the previous entry point and trajectory.
Asunto(s)
Vértebras Lumbares/diagnóstico por imagen , Vértebras Lumbares/cirugía , Ensayo de Materiales/métodos , Tornillos Pediculares/normas , Animales , Bovinos , Ensayo de Materiales/instrumentación , Distribución AleatoriaRESUMEN
PF898 is a strain of Penicillium expansum optimized for the high level production of Penicillium expansum lipase (PEL). This PEL is unique compared with other lipases in several aspects, For example, the PEL shows low sequence identities (<30%) to all other known lipases, and high percentage of hydrophobic residues in the N-terminal region. The PEL was purified to homogeneity and shown to be 28 kDa by SDS-PAGE. Crystals suitable for X-ray diffraction analysis were obtained by the sitting-drop method of vapor diffusion with ammonia sulfate as the precipitating agent at 298 K. The crystals have tetragonal lattice and unit-cell parameters of a=b=88.09 A, c=126.54 A. Diffraction data were collected to a resolution of 2.08 A on an in-house rotating-anode generator.
Asunto(s)
Lipasa/química , Lipasa/aislamiento & purificación , Penicillium/enzimología , Secuencia de Aminoácidos , Secuencia Conservada , Cristalografía por Rayos X , Datos de Secuencia Molecular , Alineación de Secuencia , Homología de Secuencia de Aminoácido , TermodinámicaRESUMEN
A Novel compound (Hbpy)2[[(H2O)3Ni(bpy)0.5Ni(bpy)(H2O)4]2[Mo5P2O23] [Ni((bpy)0.5)2(H2O)2][Mo5P2O23]].8H2O 1 (bpy = 4,4'-bipyridine) with an interpenetrating 2D network structure was synthesized hydrothermally and characterized by elemental analyses, IR, X-ray single crystal structure analysis and temperature-dependent magnetic susceptibility.
RESUMEN
Four novel three-dimensional (3D) microporous supramolecular compounds containing nanosized channels, namely, [Co(phen)2(H2O)2]2[Co(H2O)6].2BTC.21.5H2O (1), [Co(phen)2(H2O)2]2[Cu(H2O)6].2BTC.21.5H2O (2), [Co(phen)2(H2O)2]2[Mn(H2O)6].2BTC.18H2O (3), and [Zn(phen)2(H2O)2]2[Mn(H2O)6].2BTC.22.5H2O (4), were synthesized from 1,3,5-benzenetricarboxylate (BTC), 1,10-phenanthroline (phen), and the transition-metal salt(s) by self-assembly. Single-crystal X-ray structural analysis showed that the resulting 3D microporous supramolecular frameworks consist of a two-dimensional (2D) hydrogen-bonded host framework of [MII(H2O)6(BTC)2]4- (M=Co for 1, Cu for 2, Mn for 3, 4) with rectangular-shaped cavities containing [MII(phen)2(H2O)2]2+ (M=Co for 1-3, Zn for 4) guests. The guest complex is encapsulated in the 2D hydrogen-bonded host framework by hydrogen bonding and aromatic pi-pi stacking interactions, forming the 3D hydrogen-bonded framework. The catalytic activities of 1, 2, 3, and 4 were studied using hydroxylation of phenols with 30% aqueous H2O2 as a test reaction. The compounds displayed a good phenol conversion ratio and excellent channel selectivity in the hydroxylation reaction, with a maximum hydroquinone (HQ)/catechol (CAT) ratio of 3.9.