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1.
Artigo em Inglês | MEDLINE | ID: mdl-31573739

RESUMO

Interpenetration in metal-organic frameworks (MOFs) is an intriguing phenomenon with significant impacts on the properties, and functional applications of MOFs. Herein, we showed that a 7-fold interpenetrated MOF is transformed to an 8-fold interpenetrated MOF by the loss of DMF in a single-crystal-to-single-crystal manner. This is accompanied by a giant enhancement of the second harmonic generation (SHG ~125 times) and two-photon photoluminescence (~14 times). The strengthened π-π interaction between the individual diamondoid networks and intensified oscillator strength of the molecules render the augment of dipole moments and boost the nonlinear optical conversion efficiency. Large positive and negative thermal expansions of 1 occur at 30-150°C before the loss of DMF. These results offer an avenue to manipulate the NLO properties of MOFs using interpenetration and provide access to tunable single-crystal NLO devices.

2.
Adv Mater ; : e1905825, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31566283

RESUMO

Synergistic phototherapy has the potential to conquer the extreme heterogeneity and complexity of difficult tumors and result in better cancer treatment outcomes than monomodal photodynamic therapy (PDT) or photothermal therapy (PTT). However, the previous approaches to combining PDT and PTT are mainly focused on primary tumor obliteration while neglecting tumor metastasis, which is responsible for about 90% of cancer deaths. It is shown that a combined PDT/PTT approach, based on upconversion-polymer hybrid nanoparticles with surface-loaded chlorin e6 photosensitizer, can enhance primary tumor elimination and elicit antitumor immunity against disseminated tumors. The specifical arrangement of an external upconversion coating over the polymer core ensures adequate photoabsorption by the upconversion nanoparticles for the generation of reactive oxygen species upon single near-infrared light irradiation. Furthermore, it is found that synergistic phototherapy can elicit robust systemic and humoral antitumor immune responses. When combined with immune checkpoint blockades, it can inhibit tumor relapse and metastasis as well as prolong the survival of tumor-bearing mice in two types of tumor metastasis models. This study may establish a new modality for enhancing immunogenic cell death through a synergistic phototherapeutic nanoplatform and extend this strategy to overcome tumor metastasis with an augmented antitumor immune response.

3.
J Am Chem Soc ; 141(37): 14491-14495, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31487156

RESUMO

Insufficient brightness of fluorophores poses a major bottleneck for the advancement of super-resolution microscopes. Despite being widely used, many rhodamine dyes exhibit sub-optimal brightness due to the formation of twisted intramolecular charge transfer (TICT) upon photoexcitation. Herein, we have developed a new class of quaternary piperazine-substituted rhodamines with outstanding quantum yields (Φ = 0.93) and superior brightness (ε × Φ = 8.1 × 104 L·mol-1·cm-1), by utilizing the electronic inductive effect to prevent TICT. We have also successfully deployed these rhodamines in the super-resolution imaging of the microtubules of fixed cells and of the cell membrane and lysosomes of live cells. Finally, we demonstrated that this strategy was generalizable to other families of fluorophores, resulting in substantially increased quantum yields.

4.
Nanoscale ; 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31560008

RESUMO

The integration of large-scale 2D bimetallic Ag/Au nanodisk arrays with gold nanoparticles is developed for sensing DNA conformation with the assistance of 3D finite-difference time-domain simulation. The optimized system comprising Ag/Au nanodisk arrays and gold nanoparticles offers a more than 6-fold enhancement in surface plasmon resonance shift, enabling the feasibility for sensitive DNA detection with a detection limit down to 100 femtomolar. Importantly, owing to the distance-dependent nature of the surface plasmon signal, sensitive differentiation of DNA conformations can be achieved with a conventional optical measurement. This platform could provide new exciting capabilities for a reliable, reproducible, and label-free assay analysis for investigating the conformations of DNA and other biological molecules.

5.
Adv Mater ; 31(37): e1901851, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31364218

RESUMO

The development of high-performance contrast agents in magnetic resonance imaging (MRI) has recently received considerable attention, as they hold great promise and potential as a powerful tool for cancer diagnosis. Despite substantial achievements, it remains challenging to develop nanostructure-based biocompatible platforms that can generate on-demand MRI signals with high signal-to-noise ratios and good tumor specificity. Here, the design and synthesis of a new class of nanoparticle-based contrast agents comprising self-assembled NaGdF4 and CaCO3 nanoconjugates is reported. In this design, the spatial confinement of the T1 source (Gd3+ ions) leads to an "OFF" MRI signal due to insufficient interaction between the protons and the crystal lattices. However, when immersed in the mildly acidic tumor microenvironment, the embedded CaCO3 nanoparticles generate CO2 bubbles and subsequently disconnect the nanoconjugate, thus resulting in an "ON" MRI signal. The in vivo performance of these nanoconjugates shows more than 60-fold contrast enhancement in tumor visualization relative to the commercially used contrast agent Magnevist. This work presents a significant advance in the construction of smart MRI nanoprobes ideally suited for deep-tissue imaging and target-specific cancer diagnosis.

6.
Adv Mater ; : e1803474, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31432555

RESUMO

Optogenetics is an optical technique that exploits visible light for selective neuromodulation with spatio-temporal precision. Despite enormous effort, the effective stimulation of targeted neurons, which are located in deeper structures of the nervous system, by visible light, remains a technical challenge. Compared to visible light, near-infrared illumination offers a higher depth of tissue penetration owing to a lower degree of light attenuation. Herein, an overview of advances in developing new modalities for neural circuitry modulation utilizing upconversion-nanoparticle-mediated optogenetics is presented. These developments have led to minimally invasive optical stimulation and inhibition of neurons with substantially improved selectivity, sensitivity, and spatial resolution. The focus is to provide a comprehensive review of the mechanistic basis for evaluating upconversion parameters, which will be useful in designing, executing, and reporting optogenetic experiments.

7.
ACS Appl Mater Interfaces ; 11(38): 35005-35014, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31466452

RESUMO

Nanostructured photothermal membranes hold great potential for solar-driven seawater desalination; however, their pragmatic applications are often limited by substantial salt accumulation. To solve this issue, we have designed and prepared flexible and washable carbon-nanotube-embedded polyacrylonitrile nonwoven fabrics by a simple electrospinning route. The wet fabric exhibits a strong photoabsorption in a wide spectral range (350-2500 nm), and it has a photoabsorption efficiency of 90.8%. When coated onto a polystyrene foam, the fabric shows a high seawater evaporation rate of 1.44 kg m-2 h-1 under simulated sunlight irradiation (1.0 kW m-2). With a high concentration of simulated seawater as the model, the accumulation of solid salts can be clearly observed on the surface of the fabric, resulting in a severe decay of the evaporation rate. These salts can be effortlessly washed away from the fabric through a plain handwashing process. The washing process has a negligible influence on the morphology, photoabsorption, and evaporation performance of the fabric, demonstrating good durability. More importantly, a larger fabric can easily be fabricated, and the combination of washable fabrics with various parallel PS foams can facilitate the construction of large-scale outdoor evaporation devices, conferring the great potential for efficient desalination of seawater under natural sunlight.

8.
Phys Chem Chem Phys ; 21(30): 16798-16803, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31329206

RESUMO

A deep understanding of fluorescence on-off and off-on switching mechanisms is the foundation for rationally designing highly effective molecular logic gate components and systems. These mechanisms, however, are often subtle to perceive and interpret, as multiple effects may contribute to the change of fluorescence signals. Herein, we systematically investigated the 'off-on-off' switching mechanisms of a fluorescent logic gate molecule M1 using density functional theory (DFT) and time-dependent DFT (TD-DFT). Based on photoexcitation and photoemission calculations, and potential energy surface scans in the excited state, we have shown that as the pH of the medium continuously decreases and the sequential protonation of the molecule takes place, the prevention of twisted intramolecular charge transfer (TICT) followed by the activation of photo-induced electron transfer (PET) was responsible for the off-on-off switching mechanism of M1. Our results provided new insights for understanding the 'off-on-off' phenomenon in M1. The good agreement between theoretical calculations and experimental observations also suggests that computational chemistry is a powerful tool to aid the molecular design and engineering of fluorescent logic gate compounds.

9.
J Cardiovasc Pharmacol ; 74(1): 13-19, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31274838

RESUMO

We recently showed that ticagrelor reduced myocardial ischemia-reperfusion injury (IRI) and downregulated galectin-3 in the ischemic myocardium. This study tested the hypothesis that ticagrelor could reduce IRI through the NF-κB pathway. Rats were randomly divided into sham-operated group, placebo group (gastric administration of saline after IRI), ticagrelor group (gastric administration of ticagrelor after left anterior descending artery ligation), dextran sodium sulfate (DSS) group (DSS was added to drinking water 7 days before IRI), and DSS + ticagrelor group (DSS was added to drinking water 7 days before IRI and gastric administration of ticagrelor after left anterior descending artery ligation). Ticagrelor significantly reduced the infarct size and plasma cTnI at 3 and 7 days after IRI, significantly downregulated protein and mRNA expressions of NF-κB and galectin-3, and mRNA expressions of IL-6 and TNF-α in the ischemic area at 24 hours, 3 and 7 days after IRI. Ticagrelor also significantly decreased plasma high-sensitivity C-reactive protein and NT-proBNP levels at 24 hours and 3 days after IRI. Furthermore, pretreatment with DSS blocked the beneficial effects of ticagrelor. Our study indicates that the cardioprotective effect of ticagrelor might be partly mediated by inhibiting the NF-κB pathway in this rat model of IRI.

11.
Dalton Trans ; 48(27): 9949-9953, 2019 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-31237588

RESUMO

An unreported ruthenium(ii) complex containing bisoxazoline ligands has been synthesized and characterized. To test the catalytic ability of the ruthenium complex, the synthesis of anilines from nitro compounds in the presence of a mild reducing agent sodium borohydride and visible light has been developed. Mechanistic studies involving the experiment and DFT calculations suggest that the reaction could involve a radical pathway with the assistance of a photoredox catalyst.

12.
Angew Chem Int Ed Engl ; 58(27): 9262-9268, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31087740

RESUMO

Cargo transport along axons, a physiological process mediated by motor proteins, is essential for neuronal function and survival. A current limitation in the study of axonal transport is the lack of a robust imaging technique with a high spatiotemporal resolution to visualize and quantify the movement of motor proteins in real-time and in different depth planes. Herein, we present a dynamic imaging technique that fully exploits the characteristics of upconversion nanoparticles. This technique can be used as a microscopic probe for the quantitative in situ tracking of retrograde transport neurons with single-particle resolution in multilayered cultures. This study may provide a powerful tool to reveal dynamic neuronal activity and intra-axonal transport function as well as any associated neurodegenerative diseases resulting from mutation or impairment in the axonal transport machinery.

13.
Angew Chem Int Ed Engl ; 58(24): 7972-7976, 2019 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-31038839

RESUMO

Microglia, the brain-resident macrophage, are involved in brain development and contribute to the progression of neural disorders. Despite the importance of microglia, imaging of live microglia at a cellular resolution has been limited to transgenic mice. Efforts have therefore been dedicated to developing new methods for microglia detection and imaging. Using a thorough structure-activity relationships study, we developed CDr20, a high-performance fluorogenic chemical probe that enables the visualization of microglia both in vitro and in vivo. Using a genome-scale CRISPR-Cas9 knockout screen, the UDP-glucuronosyltransferase Ugt1a7c was identified as the target of CDr20. The glucuronidation of CDr20 by Ugt1a7c in microglia produces fluorescence.

14.
Medicine (Baltimore) ; 98(15): e15103, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30985664

RESUMO

Colorectal cancer has high incidence and mortality. Early diagnosis could increase patient survival, but early diagnosis has been poor in China for the past decades. The purpose of this study is to assess the polyp detection rate (PDR) and adenoma detection rate (ADR) by colonoscopy in a Chinese population, and to determine the risk factors for adenoma.This prospective study at Sichuan Provincial People's Hospital evaluated patients who underwent colonoscopy in September 2017 to February 2018. Basic information, exact insertion and withdrawal times, PDR, and ADR were assessed. Risk factors for colorectal adenoma in the adenoma-positive and adenoma-negative groups (based on pathology) were assessed by multivariable logistic regression analysis.A total of 1058 procedures with 767 polyps were analyzed. The overall PDR and ADR were 36.96% (391/1058) and 24.67% (261/1058), respectively. Occurrence of adenoma was associated with age, gender, body mass index (BMI), family history of colon cancer, personal history of adenoma, diabetes mellitus, and tobacco use. There was a significant association between withdrawal time and ADR (P < .001). In the multivariable analysis, age (OR = 1.041, 95%CI 1.028-1.055; P < .001), insertion time (OR = 0.999, 95%CI 0.998-1.000; P = .009), withdrawal time (OR = 1.009, 95%CI 1.007-1.011; P < .001), personal history of adenoma (OR = 2.572, 95%CI 1.115-5.932; P = .027), and diabetes mellitus (OR = 2.221, 95%CI 1.084-4.549; P = .029) were risk factors for colorectal adenoma detection.In a Chinese population, ADR increases with age, withdrawal time, a personal history of adenoma, and diabetes. Age, insertion and withdrawal times, and a personal history of adenoma may independently predict colorectal adenoma detection.


Assuntos
Adenoma/diagnóstico por imagem , Adenoma/epidemiologia , Colonoscopia , Neoplasias Colorretais/diagnóstico por imagem , Neoplasias Colorretais/epidemiologia , Detecção Precoce de Câncer , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco
15.
Angiology ; : 3319719841733, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30987432

RESUMO

We investigated the preventive effect of nicorandil on contrast-induced nephropathy (CIN) in patients with moderate renal insufficiency undergoing percutaneous coronary intervention (PCI). A total of 250 patients with a creatinine clearance (crCl) ≤60 mL/min undergoing PCI were randomly assigned to either a nicorandil group (nicorandil 10 mg 3 times/d and hydration; n = 125) or a control group (hydration only; n = 125). The first end point was the incidence of CIN defined as an increase in serum creatinine (Scr) levels by ≥0.5 mg/dL or ≥25% within 72 hours after exposure to the contrast medium. The secondary end points were (1) changes in Scr, blood urea nitrogen, and crCl and (2) the incidence of major adverse events during hospitalization. The incidence of CIN was 1.6% (2/125) in the nicorandil group and 9.6% (12/125) in the control group ( P = .011). There was no obvious difference in the incidence of major adverse events during hospitalization between the nicorandil and the control group (4.0% vs 4.8%, P = 1.000). Multivariate logistic regression analysis showed that nicorandil was a protective factor for CIN (odds ratios = 0.126, 95% confidence interval: -19.996 to -0.932, P = .012). Prophylactic administration of nicorandil may prevent against CIN in patients with moderate renal insufficiency undergoing PCI.

16.
Gut ; 68(10): 1813-1819, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30814121

RESUMO

OBJECTIVE: The effect of colonoscopy on colorectal cancer mortality is limited by several factors, among them a certain miss rate, leading to limited adenoma detection rates (ADRs). We investigated the effect of an automatic polyp detection system based on deep learning on polyp detection rate and ADR. DESIGN: In an open, non-blinded trial, consecutive patients were prospectively randomised to undergo diagnostic colonoscopy with or without assistance of a real-time automatic polyp detection system providing a simultaneous visual notice and sound alarm on polyp detection. The primary outcome was ADR. RESULTS: Of 1058 patients included, 536 were randomised to standard colonoscopy, and 522 were randomised to colonoscopy with computer-aided diagnosis. The artificial intelligence (AI) system significantly increased ADR (29.1%vs20.3%, p<0.001) and the mean number of adenomas per patient (0.53vs0.31, p<0.001). This was due to a higher number of diminutive adenomas found (185vs102; p<0.001), while there was no statistical difference in larger adenomas (77vs58, p=0.075). In addition, the number of hyperplastic polyps was also significantly increased (114vs52, p<0.001). CONCLUSIONS: In a low prevalent ADR population, an automatic polyp detection system during colonoscopy resulted in a significant increase in the number of diminutive adenomas detected, as well as an increase in the rate of hyperplastic polyps. The cost-benefit ratio of such effects has to be determined further. TRIAL REGISTRATION NUMBER: ChiCTR-DDD-17012221; Results.

17.
Nat Commun ; 10(1): 1391, 2019 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-30918264

RESUMO

Achieving efficient photon upconversion under low irradiance is not only a fundamental challenge but also central to numerous advanced applications spanning from photovoltaics to biophotonics. However, to date, almost all approaches for upconversion luminescence intensification require stringent controls over numerous factors such as composition and size of nanophosphors. Here, we report the utilization of dielectric microbeads to significantly enhance the photon upconversion processes in lanthanide-doped nanocrystals. By modulating the wavefront of both excitation and emission fields through dielectric superlensing effects, luminescence amplification up to 5 orders of magnitude can be achieved. This design delineates a general strategy to converge a low-power incident light beam into a photonic hotspot of high field intensity, while simultaneously enabling collimation of highly divergent emission for far-field accumulation. The dielectric superlensing-mediated strategy may provide a major step forward in facilitating photon upconversion processes toward practical applications in the fields of photobiology, energy conversion, and optogenetics.

18.
Angew Chem Int Ed Engl ; 58(21): 7073-7077, 2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-30916461

RESUMO

Charge transfer and separation are important processes governing numerous chemical reactions. Fundamental understanding of these processes and the underlying mechanisms is critical for photochemistry. Herein, we report the discovery of a new charge-transfer and separation process, namely the twisted intramolecular charge shuttle (TICS). In TICS systems, the donor and acceptor moieties dynamically switch roles in the excited state because of an approximately 90° intramolecular rotation. TICS systems thus exhibit charge shuttling. TICSs exist in several chemical families of fluorophores (such as coumarin, BODIPY, and oxygen/carbon/silicon-rhodamine), and could be utilized to construct functional fluorescent probes (i.e., viscosity- or biomolecule-sensing probes). The discovery of the TICS process expands the current perspectives of charge-transfer processes and will inspire future applications.

19.
ACS Nano ; 13(2): 2520-2525, 2019 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-30721023

RESUMO

Scintillators, which are capable of converting ionizing radiation into visible photons, are an integral part of medical, security, and commercial diagnostic technologies such as X-ray imaging, nuclear cameras, and computed tomography. Conventional scintillator fabrication typically involves high-temperature sintering, generating agglomerated powders or large bulk crystals, which pose major challenges for device integration and processability. On the other hand, colloidal quantum dot scintillators cannot be cast into compact solid films with the necessary thickness required for most X-ray applications. Here, we report the room-temperature synthesis of a colloidal scintillator comprising CsPbBr3 nanosheets of large concentration (up to 150 mg/mL). The CsPbBr3 colloid exhibits a light yield (∼21000 photons/MeV) higher than that of the commercially available Ce:LuAG single-crystal scintillator (∼18000 photons/MeV). Scintillators based on these nanosheets display both strong radioluminescence (RL) and long-term stability under X-ray illumination. Importantly, the colloidal scintillator can be readily cast into a uniform crack-free large-area film (8.5 × 8.5 cm2 in area) with the requisite thickness for high-resolution X-ray imaging applications. We showcase prototype applications of these high-quality scintillating films as X-ray imaging screens for a cellphone panel and a standard central processing unit chip. Our radiography prototype combines large-area processability with high resolution and a strong penetration ability to sheath materials, such as resin and silicon. We reveal an energy transfer process inside those stacked nanosheet solids that is responsible for their superb scintillation performance. Our findings demonstrate a large-area solution-processed scintillator of stable and efficient RL as a promising approach for low-cost radiography and X-ray imaging applications.

20.
Angew Chem Int Ed Engl ; 58(13): 4328-4333, 2019 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-30706599

RESUMO

Crystal-state luminophores have been of great interest in optoelectronics for years, whereas the excited state regulation at the crystal level is still restricted by the lack of control ways. We report that the singlet-triplet emissive property can be profoundly regulated by crystal conformational distortions. Employing fluoro-substituted tetrakis(arylthio)benzene luminophores as prototype, we found that couples of molecular conformations formed during different crystallizations. The deformable carbon-sulphur bond essentially drove the distortion of the molecular conformation and varied the stacking mode, together with diverse non-covalent interactions, leading to the proportional adjustment of the fluorescence and phosphorescence bands. This intrinsic strategy was further applied for solid-state multicolor emissive conversion and mechanoluminescence, probably offering new insights for design of smart crystal luminescent materials.

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