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1.
Heliyon ; 10(6): e27914, 2024 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-38509877

RESUMO

Systemic air embolism is a fatal complication of computed tomography-guided percutaneous lung biopsy. Here, we report a case of acute coronary artery air embolism following computed tomography (CT) guided percutaneous lung biopsy. The patient exhibited cardiac symptoms, and CT showed air density in left ventricle and aorta, indicating air embolism. Trendelenburg positioning and coronary angiography were performed during the treatment, and the patient was discharged without obvious complications.

2.
Sensors (Basel) ; 23(22)2023 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-38005553

RESUMO

A sandwiched piezoelectric accelerometer is developed and optimized for acquiring low-frequency, wide-band seismic data. The proposed accelerometer addresses the challenges of capturing seismic signals in the low-frequency range while maintaining a broad frequency response through the design of multi-stage charge amplifiers and a sandwiched structure. The device's design, fabrication process, and performance evaluation are discussed in detail. Experimental results demonstrate its performance in amplitude and phase response characteristics.

3.
Research (Wash D C) ; 6: 0255, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37899773

RESUMO

The limitations of autologous bone grafts necessitate the development of advanced biomimetic biomaterials for efficient cranial defect restoration. The cranial bones are typical flat bones with sandwich structures, consisting of a diploe in the middle region and 2 outer compact tables. In this study, we originally developed 2 types of flat-bone-mimetic ß-tricalcium phosphate bioceramic scaffolds (Gyr-Comp and Gyr-Tub) by high-precision vat-photopolymerization-based 3-dimensional printing. Both scaffolds had 2 outer layers and an inner layer with gyroid pores mimicking the diploe structure. The outer layers of Gyr-Comp scaffolds simulated the low porosity of outer tables, while those of Gyr-Tub scaffolds mimicked the tubular pore structure in the tables of flat bones. The Gyr-Comp and Gyr-Tub scaffolds possessed higher compressive strength and noticeably promoted in vitro cell proliferation, osteogenic differentiation, and angiogenic activities compared with conventional scaffolds with cross-hatch structures. After implantation into rabbit cranial defects for 12 weeks, Gyr-Tub achieved the best repairing effects by accelerating the generation of bone tissues and blood vessels. This work provides an advanced strategy to prepare biomimetic biomaterials that fit the structural and functional needs of efficacious bone regeneration.

4.
Environ Res ; 236(Pt 1): 116797, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37527746

RESUMO

Due to severe disturbances caused by rapid urbanization and industrialization, river ecosystems have evolved into complex natural-social composite ecosystems. At present, there is no unified evaluation method for the effect of river restoration in China. The existing research fails to fully integrate the "natural-social" characteristics of rivers, and pays less attention to the river section scale, which is not conducive to the development of accurate pollution control work. In this paper, we first put forward the division method of river section type which conforms to the "nature-society" dual attribute characteristics of the river, and divides the river section into "ecological/service/dual" functional "urban/rural" river section. Then a method for evaluating the restoration effect of different river sections based on index weight optimization was proposed. Based on the type of river section, the weights of 17 indexes were optimized, and the common evaluation method of restoration effect-multi-index evaluation method was improved. In addition, the application and verification of the established method were carried out on the main stream of Qingyi River and its typical tributaries. The evaluation results show that only the restoration effect of Baling River decreased from average in 2019 to acceptable in 2021, and ΔH (the change of the mean score of the target factor after repair) decreased from 15.6% to 6.2%. It was found that for the river sections where the repair effect cannot be maintained stably (such as Baling River), the previous methods paid more attention to the overall effect and easily ignored the specific problems. The improved method can identify problems more easily and facilitate timely post-maintenance. To further optimize the repair effect of Qingyi River, it is suggested that the restoration effect should be strengthened from the aspects of pollution source control, water quality improvement, aquatic restoration, continuous monitoring and evaluation. The evaluation results can provide a reference for the design, operation, and maintenance of restoration projects in small and medium-sized rivers.

5.
Nat Commun ; 14(1): 4211, 2023 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-37452049

RESUMO

Aqueous zinc batteries are ideal candidates for grid-scale energy storage because of their safety and low-cost aspects. However, the production of large-format aqueous Zn batteries is hindered by electrolyte consumption, hydrogen gas evolution and accumulation, and Zn dendrites growth. To circumvent these issues, here we propose an "open" pouch cell design for large-format production of aqueous Zn batteries, which can release hydrogen gas and allow the refilling of the electrolyte components consumed during cell cycling. The cell uses a gel electrolyte containing crosslinked kappa (k)-carrageenan and chitosan. It bonds water molecules and hinders their side reaction with Zn, preventing electrolyte leakage and fast evaporation. As a proof-of-concept, we report the assembly and testing of a Zn | |ZnxV2O5·nH2O multi-layer "open" pouch cell using the carrageenan/chitosan gel electrolyte, which delivers an initial discharge capacity of 0.9 Ah and 84% capacity retention after 200 cycles at 200 mA g‒1, 370 kPa and 25 °C.


Assuntos
Quitosana , Zinco , Carragenina , Metais , Eletrólitos , Hidrogênio , Água
6.
Nanotechnology ; 34(43)2023 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-37506679

RESUMO

Field-effect transistor (FET) biosensors based on two-dimensional materials have gained extensive attention due to their high sensitivity, label-free detection capability, and fast response. Molybdenum disulfide (MoS2), with tunable bandgap, high surface-to-volume ratio, and smooth surface without dangling bonds, is a promising material for FET biosensors. Previous reports have demonstrated the fabrication of MoS2-FET biosensors and their high sensitivity detection of proteins. However, most prior research has focused on the realization of MoS2-FETs for detecting different kinds of proteins or molecules, while comprehensive analysis of the sensing mechanism and dominant device factors of MoS2-FETs in response to proteins is yet to investigate. In this study, we first fabricated MoS2-FET biosensor and detected different types of proteins (immunoglobulin G (IgG),ß-actin, and prostate-specific antigen (PSA)). Secondly, we built the model of the device and analyzed the sensing mechanism of MoS2-FETs in response to proteins. Experimental and modeling results showed that the induced doping effect and gating effect caused by the target protein binding to the device surface were the major influential factors. Specifically, the channel doping concentration and gate voltage (Vg) offset exhibited monotonic change as the concentration of the protein solution increases. For example, the channel doping concentration increased up to ∼37.9% and theVgoffset was ∼-1.3 V with 10-7µgµl-1IgG. The change was less affected by the device size. We also investigated the effects of proteins with opposite acid-base properties (ß-actin and PSA) to IgG on the device sensing mechanism.ß-actin and PSA exhibited behavior opposite to that of IgG. Additionally, we studied the response behavior of MoS2-FETs with different dimensions and dielectric materials (channel length, MoS2thickness, dielectric layer thickness, dielectric layer material) to proteins. The underlying mechanisms were discussed in details. This study provides valuable guidelines for the design and application of MoS2-FET biosensors.


Assuntos
Técnicas Biossensoriais , Antígeno Prostático Específico , Humanos , Masculino , Molibdênio/química , Actinas , Técnicas Biossensoriais/métodos , Imunoglobulina G
7.
Nat Commun ; 14(1): 2418, 2023 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-37105973

RESUMO

The performance of ultrasonic transducers is largely determined by the piezoelectric properties and geometries of their active elements. Due to the brittle nature of piezoceramics, existing processing tools for piezoelectric elements only achieve simple geometries, including flat disks, cylinders, cubes and rings. While advances in additive manufacturing give rise to free-form fabrication of piezoceramics, the resultant transducers suffer from high porosity, weak piezoelectric responses, and limited geometrical flexibility. We introduce optimized piezoceramic printing and processing strategies to produce highly responsive piezoelectric microtransducers that operate at ultrasonic frequencies. The 3D printed dense piezoelectric elements achieve high piezoelectric coefficients and complex architectures. The resulting piezoelectric charge constant, d33, and coupling factor, kt, of the 3D printed piezoceramic reach 583 pC/N and 0.57, approaching the properties of pristine ceramics. The integrated printing of transducer packaging materials and 3D printed piezoceramics with microarchitectures create opportunities for miniaturized piezoelectric ultrasound transducers capable of acoustic focusing and localized cavitation within millimeter-sized channels, leading to miniaturized ultrasonic devices that enable a wide range of biomedical applications.

8.
Org Biomol Chem ; 20(27): 5481-5488, 2022 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-35775821

RESUMO

Natural enediyne antibiotics are powerful DNA-cleavage agents due to the presence of the highly reactive hex-3-ene-1,5-diyne units. However, the complicated chemical structure and thermal instability make their synthesis, derivatization, and storage challenging. Heterocycle-fused enediynes, which exhibit strong antineoplastic activity, are promising analogues of natural enediynes for medicinal applications. To this end, a series of maleimide-based enediynes with macrocyclic lactone moieties were synthesized through the Sonagashira coupling reaction. Differential scanning calorimetry and electron paramagnetic resonance results showed that these macrocyclic enediynes exhibited a rather low onset temperature and the ability to generate radicals at physiological temperature. In addition, the structure-activity relationship of enediynes was analyzed by changing the ring size and the substituents on the propargyl group. Cellular experiments indicated that the diradicals produced by these enediynes efficiently cleaved DNA and disrupted the cell cycle distribution, and consequently induced tumor cell death via an apoptosis pathway at low half inhibitory concentrations. Computational studies suggested that the maleimide moiety promoted the propargyl-allenyl rearrangement of the cyclic enediyne, enabling the generation of diradical species through the Myers-Saito cyclization, and then abstracted hydrogen atoms from the H-donors.


Assuntos
Enedi-Inos , Lactonas , Antibióticos Antineoplásicos , Ciclização , DNA , Enedi-Inos/química , Enedi-Inos/farmacologia , Maleimidas/farmacologia
9.
Science ; 376(6599): 1287-1293, 2022 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-35709267

RESUMO

Advances in additive manufacturing techniques have enabled the creation of stimuli-responsive materials with designed three-dimensional (3D) architectures. Unlike biological systems in which functions such as sensing, actuation, and control are closely integrated, few architected materials have comparable system complexity. We report a design and manufacturing route to create a class of robotic metamaterials capable of motion with multiple degrees of freedom, amplification of strain in a prescribed direction in response to an electric field (and vice versa), and thus, programmed motions with self-sensing and feedback control. These robotic metamaterials consist of networks of piezoelectric, conductive, and structural elements interwoven into a designed 3D lattice. The resulting architected materials function as proprioceptive microrobots that actively sense and move.

10.
J Mater Chem B ; 9(19): 4056-4064, 2021 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-33949615

RESUMO

Combined photothermal therapy/chemotherapy by co-delivery of a photosensitizer (PS) and a chemotherapeutic drug has demonstrated great potential for cancer treatment. The intrinsic drawbacks of traditional drug delivery systems (DDSs), such as tedious synthetic procedures, side effects originated from the carrier materials, low loading efficiency, and uncontrolled drug release, however, have impaired their further advancement. On the other hand, enediyne antibiotics are highly cytotoxic toward cancer cells through the generation of lethal carbon radicals via thermal-induced cyclization, endowing them with great potential to achieve enhanced synergistic anticancer performance by incorporation with the photothermal effect of PS. To this end, a carrier-free and NIR/acid dual-responsive DDS was constructed for combined photothermal therapy/chemotherapy. The facile co-assembly of maleimide-based enediyne and PS IR820 was achieved in aqueous solution to give nanoparticles (EICN) with a hydrodynamic diameter of 90 nm and high stability. In vitro study confirmed the acid/NIR dual-responsive degradation and drug release, free radical generation and DNA-cleaving ability of EICN, which was accomplished by the corporation of enediyne and IR820 moieties. Further tests on HeLa cells verified the excellent synergistic anticancer performance of EICN including the improved cellular uptake, NIR-enhanced drug release, DNA damage and histone deacetylase inhibitor capacity. Overall, this carrier-free DDS with dual acid/NIR-responsivity would potentially provide new insights for the development of combined photothermal/chemotherapy.


Assuntos
Antineoplásicos/química , Enedi-Inos/química , Verde de Indocianina/análogos & derivados , Raios Infravermelhos , Nanopartículas/química , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Clivagem do DNA/efeitos dos fármacos , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Hipertermia Induzida , Verde de Indocianina/química , Neoplasias/tratamento farmacológico , Neoplasias/terapia , Tamanho da Partícula , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/metabolismo , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/uso terapêutico , Fototerapia , Oxigênio Singlete/química , Oxigênio Singlete/metabolismo
11.
J Mater Chem B ; 9(22): 4502-4509, 2021 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-34019610

RESUMO

Myers-Saito cycloaromatization (MSC) is the working mechanism of many natural enediyne antibiotics with high antitumor potency. However, the presence of the equilibrium between diradical and zwitterionic intermediates in MSC severely hinders further improvement in cytotoxicity toward tumor cells. To this end, a series of maleimide-based enediynes with cyclopropane moieties were synthesized for enhanced cytotoxicity toward tumor cells. By taking advantage of radical clock reactions, the diradical intermediates generated from MSC would rearrange to new diradicals with much longer separation and weaker interactions between two radical centers. The computational study suggested a low energy barrier (4.4 kcal mol-1) for the radical rearrangement through the cyclopropane ring-opening process. Thermolysis experiments confirmed that this radical rearrangement results in the formation of a new diradical intermediate, followed by abstracting hydrogen atoms from 1,4-cyclohexadiene. Interestingly, the DNA cleavage ability and cytotoxicity of enediynes were significantly enhanced after the introduction of cyclopropane moieties. In addition, these maleimide-based enediynes exhibited a similar cytotoxicity under hypoxic conditions to that under normoxic conditions, which is beneficial for treating solid tumors where hypoxic environments frequently lead to deteriorated efficiency of many antitumor drugs. Docking studies indicated that the diradical intermediate was located between the minor groove of DNA with a binding energy of -7.40 kcal mol-1, which is in favor of intracellular DNA damage, and thereby inducing cell death via an apoptosis pathway as suggested by immunofluorescence analysis.


Assuntos
Sobrevivência Celular/efeitos dos fármacos , Ciclopropanos/química , Enedi-Inos/química , Maleimidas/química , Oxigênio/metabolismo , Ensaios de Seleção de Medicamentos Antitumorais , Humanos
12.
Chem Commun (Camb) ; 57(39): 4787-4790, 2021 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-33982730

RESUMO

Cyclic ethers are important scaffolds employed in the synthesis of various natural products and pharmaceutical ingredients. A novel free radical-initiated reaction between cyclic ethers and maleimide iodides through C-H activation is developed, avoiding the use of transition metallic catalysts. This method provides a simple approach to derive cyclic ethers, which were further applied in various cross coupling reactions.

13.
Open Med (Wars) ; 16(1): 1-13, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33336077

RESUMO

Zymogen granule protein 16B (ZG16B) has been identified in various cancers, while so far the association between ZG16B and breast cancer hasn't been explored. Our aim is to confirm whether it can serve as a prognostic biomarker in breast cancer. In this study, Oncomine, Cancer Cell Line Encyclopedia (CCLE), Ualcan, and STRING database analyses were conducted to detect the expression level of ZG16B in breast cancer with different types. Kaplan-Meier plotter was used to analyze the prognosis of patients with high or low expression of ZG16B. We found that ZG16B was significantly upregulated in breast cancer. Moreover, ZG16B was closely associated with foregone biomarkers and crucial factors in breast cancer. In the survival analysis, high expression of ZG16B represents a favorable prognosis in patients. Our work demonstrates the latent capacity of ZG16B to be a biomarker for prognosis of breast cancer.

14.
J Org Chem ; 86(2): 1549-1559, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33372795

RESUMO

The follow-up reaction pathways of the diradical species formed from cycloaromatization of enediynes or enyne-allenes determine their ability of H-abstraction from DNA, significantly affecting their biological activity performance. To gain a deeper understanding of subsequent reaction pathways of the diradical intermediates formed from acyclic enediynes based on maleimide-assisted rearrangement and cycloaromatization (MARACA), a maleimide-based enediyne featuring methylene groups adjacent to the propargyl sites of the terminal alkynes was synthesized through the Sonogashira coupling reaction. Three thermal cyclization products after intramolecular hydrogen atom transfer (HAT) were obtained from the thermolysis experiment and their structures were confirmed by 1D and 2D nuclear magnetic resonance spectroscopic analysis. Density functional theory was employed to analyze the important elementary steps including rearrangement, cycloaromatization, and intramolecular HAT processes toward the formation of the cyclized products, where the low-energy barriers of HAT pathways relative to the formation of diradicals from cycloaromatization were successfully identified. Overall, the HAT processes to consume diradicals intramolecularly have become competitive with that of intermolecular H-abstraction, implying that the DNA-cleavage ability of enediynes can be further boosted once the HAT processes are halted. This study offers a promising direction for designing novel and potent acyclic enediynes for antitumor applications.

15.
Artigo em Inglês | MEDLINE | ID: mdl-32746196

RESUMO

Currently, blindness cannot be cured and patients' living quality can be compromised severely. Ultrasonic (US) neuromodulation is a promising technology for the development of noninvasive cortical visual prosthesis. We investigated the feasibility of transcranial focused ultrasound (tFUS) for noninvasive stimulation of the visual cortex (VC) to develop improved visual prosthesis. tFUS was used to successfully evoke neural activities in the VC of both normal and retinal degenerate (RD) blind rats. Our results showed that blind rats showed more robust responses to ultrasound stimulation when compared with normal rats. ( , two-sample t-test). Three different types of ultrasound waveforms were used in the three experimental groups. Different types of cortical activities were observed when different US waveforms were used. In all rats, when stimulated with continuous ultrasound waves, only short-duration responses were observed at "US on and off" time points. In comparison, pulsed waves (PWs) evoked longer low-frequency responses. Testing different parameters of PWs showed that a pulse repetition frequency higher than 100 Hz is required to obtain the low-frequency responses. Based on the observed cortical activities, we inferred that acoustic radiation force (ARF) is the predominant physical mechanism of ultrasound neuromodulation.


Assuntos
Córtex Visual , Animais , Humanos , Ratos , Ondas Ultrassônicas , Ultrassonografia , Córtex Visual/diagnóstico por imagem
16.
Mol Biol Rep ; 47(10): 7831-7842, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33009967

RESUMO

Non-SMC condensin I complex subunit H (NCAPH) is a structural component of chromosomes during mitosis, which up-regulates in various cancers. However, the role of NCAPH in breast cancer still hasn't been clearly explored. Our aim is to confirm the value of NCAPH as a prognostic biomarker of breast cancer. We revealed the high expression of NCAPH in breast cancer by using Oncomine, Ualcan and GOBO analysis. Quantitative Real-time PCR (qRT-PCR) analysis was conducted to detect the mRNA expression of NCAPH in MCF-7 and MCF-10A cells, and thus higher mRNA level of NCAPH in MCF-7 cells was confirmed. STRING and gene enrich analysis were conducted to explore the interaction between NCAPH and other proteins, hence the functionality of NCAPH in mitosis is demonstrated. With Kaplan-Meier plotter we found that upregulation of NCAPH is indicative of a poor prognosis especially in hormone receptor positive breast cancer. We confirmed the potential competence of NCAPH as a promising biomarker in breast cancer prognosis.


Assuntos
Biomarcadores Tumorais/biossíntese , Neoplasias da Mama/metabolismo , Neoplasias da Mama/mortalidade , Proteínas de Ciclo Celular/biossíntese , Proteínas de Neoplasias/biossíntese , Proteínas Nucleares/biossíntese , Biomarcadores Tumorais/genética , Neoplasias da Mama/genética , Proteínas de Ciclo Celular/genética , Intervalo Livre de Doença , Feminino , Humanos , Células MCF-7 , Proteínas de Neoplasias/genética , Proteínas Nucleares/genética , Taxa de Sobrevida
17.
J Org Chem ; 85(15): 9808-9819, 2020 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-32657121

RESUMO

Acyclic enediynes are generally inactive under physiological conditions to be used as antitumor agents like their natural enediyne counterparts. A new mechanism named as maleimide-assisted rearrangement and cycloaromatization (MARACA) is uncovered to trigger the reactivity of acyclic enediynes. Through this mechanism, cascade 1,3-proton transfer processes are accelerated with the maleimide moiety at the ene position to enable the acyclic enediynes to undergo cycloaromatization and generate reactive radicals under physiological conditions. Computational studies suggest that the highest energy barrier for MARACA is 26.0 kcal/mol, much lower than that of Bergman cyclization pathway (39.6 kcal/mol). Experimental results show that maleimide-based enediynes exhibit low onset temperature, fast generation of radical species at 37 °C, and much faster reaction in aqueous solution than in nonpolar solvent, which is beneficial to achieve both high reactivity in physiological environment and high stability for storage and delivery in nonpolar media. The generated radical species are capable of causing high percentage of double-strand (ds) DNA cleavage, leading to significant cytotoxicity toward a panel of cancer cell lines with half inhibition concentration down to submicromolar level. Overall, the discovery of the MARACA mechanism provides a platform for designing novel acyclic enediynes with high potency for antitumor applications.


Assuntos
Antineoplásicos , Neoplasias , Antineoplásicos/farmacologia , Ciclização , Enedi-Inos/farmacologia , Humanos , Maleimidas/farmacologia
18.
J Mater Chem B ; 8(9): 1971-1979, 2020 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-32068226

RESUMO

Enyne-allene compounds undergo Myers-Saito cyclization at physiological temperature to generate diradical intermediates that are capable of inducing DNA damage and cell death. The high reactivity of enyne-allene however limits their promising prospect as anticancer agents due to the spontaneous cyclization during storage and delivery. Regulating the cyclization process by taking advantage of the characteristics of a tumor cellular microenvironment, such as employing a low pH value to activate the cyclization process, is thus of essential importance. In this work, a novel enediyne (EDY) system with locked carbonyl groups was specifically designed and synthesized. Unlocking the protected carbonyl groups in the presence of acid would facilitate the rearrangement of propargyl moieties into an allene group, enabling the formation of an enyne-allene structure and occurrence of Myers-Saito cyclization. The pH-dependent diradical generation and DNA-cleavage ability of the designed EDY system were confirmed by electron paramagnetic resonance analysis and DNA gel electrophoresis. A promising cytotoxicity against HeLa cells with half inhibition concentrations (IC50) as low as 1.40 µM was obtained, which was comparable to those of many commercially applied anticancer drugs. Further in vitro experiments revealed that this EDY system induced intracellular DNA damage and subsequently resulted in S-phase arrest and cytotoxicity through programmed apoptosis.


Assuntos
Alcinos/farmacologia , Antineoplásicos/farmacologia , Alcinos/síntese química , Alcinos/química , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ciclização , Teoria da Densidade Funcional , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Estrutura Molecular , Relação Estrutura-Atividade , Temperatura
19.
Chem Asian J ; 14(23): 4352-4357, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31777169

RESUMO

A maleimide-based acyclic enediyne with salicylaldiminato substituents at the alkyne termini was synthesized, which was further chelated with three kinds of metal-ions, CuII , ZnII , and MgII , and form metalloenediynes. The cycloaromatization of this thermally inactive enediyne ligand was greatly accelerated through the coordination with metal ions. Specifically, the CuII -metalloenediyne showed an extremely low onset temperature of 55 °C and underwent spontaneous cycloaromatization at ambient temperature to produce free radicals, followed by generation of reactive oxygen species in the physiological environment. The metalloenediyne exhibited excellent DNA cleavage ability and high cytotoxicity towards HeLa cells, with half-maximal inhibitory concentration values comparable to many commercial antitumor agents. The combination of the electron-withdrawing effect of the maleimide moiety at the ene position and metal coordination at the yne termini provides a new inspiration for designing and synthesizing highly efficient enediyne antitumor agents.


Assuntos
Enedi-Inos/química , Radicais Livres/metabolismo , Antineoplásicos/química , Antineoplásicos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Clivagem do DNA/efeitos dos fármacos , Radicais Livres/química , Células HeLa , Humanos , Ligantes , Maleimidas/química , Metais/química , Espécies Reativas de Oxigênio/metabolismo
20.
ACS Appl Mater Interfaces ; 11(46): 43473-43479, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31702891

RESUMO

The development of artificial synapses has enabled the establishment of brain-inspired computing systems, which provides a promising approach for overcoming the inherent limitations of current computer systems. The two-terminal memristors that faithfully mimic the function of biological synapses have intensive prospects in the neural network field. Here, we propose a high-performance artificial synapse based on oxide tunnel junctions with oxygen vacancy migration. Both short-term and long-term plasticities are mimicked in one device. The oxygen vacancy migration through oxide ultrathin films is utilized to manipulate long-term plasticity. Essential synaptic functions, such as paired pulse facilitation, post-tetanic potentiation, as well as spike-timing-dependent plasticity, are successfully implemented in one device by finely modifying the shape of the pre- and postsynaptic spikes. Ultralow femtojoule energy consumption comparable to that of the human brain indicates its potential application in efficient neuromorphic computing. Oxide tunnel junctions proposed in this work provide an alternative approach for realizing energy-efficient brain-like chips.

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