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1.
Phys Chem Chem Phys ; 25(14): 9987-9998, 2023 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-36960706

RESUMO

We report yellow-orange emitting phosphors Sr9-xCaxMg1.5(PO4)7:0.05Eu2+ (SCxMPO:Eu2+, x = 0.5-2.5) and Sr9-yBayMg1.5(PO4)7:0.05Eu2+ (SByMPO:Eu2+, y = 0.5-3.0) with broad emission bands (450-800 nm). All these phosphors can be excited efficiently by blue light and n-UV light. Their crystal structure, photoluminescence spectra, fluorescence decay curves and thermal stability were investigated in detail. As doping concentrations of Ca2+ or Ba2+ increase, Eu2+ emitting centers will selectively occupy different Sr2+ sites, thus leading to the regulation of optical spectra of SCxMPO:Eu2+ and SByMPO:Eu2+. Accordingly, the emission colors of SCxMPO:Eu2+ and SByMPO:Eu2+ samples can gradually turn from yellow to orange when excited using 460 nm blue light. And the emission colors of a given sample can also be varied under different excitations because there are three kinds of emitting centers in SCxMPO:Eu2+ and SByMPO:Eu2+. In addition, introducing Ca2+ and Ba2+ can enhance the thermal stability of the phosphors obviously, and overall, the thermal stability of SByMPO:Eu2+ is better than that of SCxMPO:Eu2+. We chose SB2.5MPO:zEu2+ as an example to further investigate its photoluminescence properties, and found that the optimal doping concentration of Eu2+ is 0.08, and dipole-quadrupole interaction is dominated in the concentration quenching mechanism. Furthermore, high-quality warm white light can be obtained by two ways: (a) 470 nm blue LED chip + SC1.5MPO:Eu2+ [CCT = 3639 K, Ra = 82.21] and (b) 470 nm blue LED chip + SB2.5MPO:Eu2+ and YAG:Ce3+ [CCT = 4284 K, Ra = 86.69]. The excellent performances indicate that SCxMPO:Eu2+ and SByMPO:Eu2+ are attractive candidates for warm WLEDs.

2.
Biomed Chromatogr ; 36(12): e5483, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35975594

RESUMO

Aloin A/B and aloesin are the major bioactive constituents in Aloe vera, with diverse pharmacological activities, including anti-bacterial, anti-tumour, anti-inflammatory and intestinal regulation. However, the in vivo metabolism of aloin A/B and aloesin is still unclear. In this study, the metabolic processes of aloin A/B and aloesin in rats were investigated using ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) and MetaboLynx™ software with the mass defect filter technique. Based on the proposed method, the prototype components of three compounds were all detected in rat plasma, urine and feces. Meanwhile, 25 aloin A/B metabolites (six phase I, three phase II, 16 phase I combined with phase II) and three aloesin metabolites (two phase I and one phase II) were detected in rats after oral administration of aloin A, aloin B and aloesin, and the main biotransformation reactions were hydroxylation, oxidation, methylation, acetylation and glucuronidation. In addition, aloin A and aloin B can be transformed into each other in vivo and the metabolic profiles of aloin A and aloin B are identical. These results provide essential data for further pharmaceutical research and clinical application of aloin A/B and aloesin.


Assuntos
Medicamentos de Ervas Chinesas , Espectrometria de Massas em Tandem , Ratos , Animais , Cromatografia Líquida de Alta Pressão/métodos , Espectrometria de Massas em Tandem/métodos , Ratos Sprague-Dawley
3.
Environ Toxicol ; 37(3): 637-649, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34894065

RESUMO

Diabetic nephropathy (DN) is a diabetic complication that can cause renal failure. ß-amyrin has been identified to possess anti-diabetic property. This study was designed to evaluate the potential role of ß-amyrin in DN and its underlying mechanism. Streptozotocin-induced diabetic mice were used as the in vivo model, and high glucose (HG)-stimulated human proximal tubular HK-2 cells were utilized as the in vitro model. Renal histological changes in mice were assessed by hematoxylin-eosin and periodic acid-Schiff staining. HK-2 cell viability and apoptosis were detected by Cell Counting Kit-8 assay and flow cytometry analysis, respectively. ß-amyrin was found to ameliorate kidney injury in DN mice and suppressed inflammatory response as well as apoptosis of HG-stimulated HK-2 cells. miR-181-5p expression in murine renal tissues and HK-2 cells was detected by in situ hybridization (ISH) and fluorescence in situ hybridization (FISH). MiR-181b-5p, a previously identified target for diabetic kidney disease, was downregulated in renal tissues and HG stimulated HK-2 cells, and ß-amyrin induced the upregulation of miR-181b-5p. Binding relationship between miR-181b-5p and high mobility group box 2 (HMGB2) was confirmed by luciferase reporter assay. MiR-181b-5p bound to 3' untranslated region of HMGB2 to suppress its expression. As shown by immunohistochemical staining and immunofluorescence staining, HMGB2 was upregulated in the in vivo and in vitro models of DN, and ß-amyrin induced the downregulation of HMGB2. Moreover, HMGB2 overexpression neutralized the suppressive effects of miR-181b-5p elevation on the inflammatory response and apoptosis of HG-treated HK-2 cells. Overall, ß-amyrin ameliorates DN in mice and suppresses inflammatory response and apoptosis of HG-stimulated HK-2 cells via the miR-181b-5p/HMGB2 axis.


Assuntos
Diabetes Mellitus Experimental , Nefropatias Diabéticas , MicroRNAs , Animais , Nefropatias Diabéticas/genética , Glucose , Proteína HMGB2 , Hibridização in Situ Fluorescente , Camundongos , MicroRNAs/genética , Ácido Oleanólico/análogos & derivados
4.
J Asian Nat Prod Res ; 24(8): 713-721, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34647509

RESUMO

Three new caffeoyl derivatives (1-3), together with two known ones (4-5), were isolated from the whole plant of Elephantopus scaber Linn. The structures of the new compounds were elucidated using detailed spectroscopic analysis. Compound 4 was obtained and its NMR data were given for the first time. All isolates were evaluated for their anti-inflammatory activity against lipopolysaccharide (LPS)-stimulated nitric oxide (NO) production and pro-inflammatory cytokines release in RAW 264.7 cells. Compounds 2-5 showed mild inhibitory activities with IC50 values ranging from 64.78 to 87.21 µM, and 3-4 could inhibit LPS-induced tumor necrosis factor-α (TNF-α) production.


Assuntos
Asteraceae , Lipopolissacarídeos , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Asteraceae/química , Lipopolissacarídeos/farmacologia , Camundongos , Estrutura Molecular , Óxido Nítrico , Células RAW 264.7
5.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 39(6): 565-570, 2022 Jun 10.
Artigo em Zh | MEDLINE | ID: mdl-35773756

RESUMO

OBJECTIVE: To investigate the factors affecting phenotypes in the patients of methylmalonic acidemia combined with homocysteinemia cblC type with MMACHC c.609G>A homologous variant. METHODS: A retrospective study on the clinical manifestations, complications, treatment, and outcome in 164 patients of cblC type with MMACHC c.609G>A homologous variant was conducted. The patients were diagnosed by biochemical and genetic analysis from January 1998 to December 2020. RESULTS: Among the 164 patients, 2 cases were prenatally diagnosed and began treatment after birth. They are 3 and 12 years old with normal physical and mental development. Twenty-one cases were diagnosed by newborn screening. Among them, 15 cases had with normal development. They were treated from the age of two weeks at the asymptomatic period. Six cases began treatment aged 1 to 3 months after onset. Their development was delayed. One hundred and forty-one cases were clinically diagnosed. Their onset age ranges from a few minutes after birth to 6 years old. 110 cases had early-onset (78.0%). 31 cases had late-onset (22.0%). Five of them died. 24 patients lost to follow-up. Of the 141 clinically diagnosed patients, 130 (92.2%) with psychomotor retardation, 69 (48.9%) with epilepsy, 39 (27.7%) with anemia, 30 (21.3%) had visual impairment, 27 (19.1%) had hydrocephalus, 26 (18.4%) had feeding difficulties, 7 (5.0%) with liver damage, and 5 (3.5%) with metabolic syndrome. The frequency of hydrocephalus and seizures was significantly higher in the early-onset group. The urinary methylmalonic acid increased significantly in the patients with epilepsy. During the long-term follow-up, the level of plasma total homocysteine in the seizure-uncontrolled group was significantly higher than that in the seizure-controlled group, the difference had a statistical significance (P<0.05). CONCLUSION: Most of the patients with MMACHC c.609G>A homozygous variant had early-onset disease, with a high mortality and disability rate. If not treated in time, it will lead to neurological damage, resulting in epilepsy, mental retardation, hydrocephalus, and multiple organ damage. Pre-symptomatic diagnosis and treatment are crucial to prevent irreversible neurological damage. Neonatal screening and prenatal diagnosis are important to improve the outcome of the patients.


Assuntos
Erros Inatos do Metabolismo dos Aminoácidos , Hidrocefalia , Oxirredutases , Erros Inatos do Metabolismo dos Aminoácidos/diagnóstico , Erros Inatos do Metabolismo dos Aminoácidos/enzimologia , Erros Inatos do Metabolismo dos Aminoácidos/genética , Feminino , Humanos , Hidrocefalia/diagnóstico , Hidrocefalia/enzimologia , Hidrocefalia/genética , Mutação , Oxirredutases/genética , Fenótipo , Gravidez , Estudos Retrospectivos , Convulsões/genética
6.
Nanotechnology ; 32(20): 205604, 2021 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-33567415

RESUMO

Curcumin (Cur), appeared to provide huge potential in biomedical application. However, its therapeutic efficacy was greatly limited as the result of poor solubility and instability. To address these limitations, we create a new type of hollow mesoporous titania nanoparticle (HMTN) to encapsulate Cur. HMTN was decorated with a layer of hydrophilic polyethylenimine (PEI), which controlled the release rate of Cur inside the pore due to its dendritic structure. Combined with the folic acid (FA) mediated targeting effect, the potential multifunctional Cur loaded titania nanoparticle (Cur-FA-PEI-HMTN) showed excellent biocompatibility and bioavailability, as well as the UV-responsive drug release properties. The operating parameters to prepare hollow structure were studied and the Cur-FA-PEI-HMTN nanosystem had been fully characterized by Brunauer-Emmet-Teller, Fourier transform infrared spectroscopy, transmission electron microscope, thermal gravity analysis, differential thermal analysis, x-ray diffraction, dynamic light scattering and zeta potential. In addition, the hemolytic test, as well as CCK8, flow cytometry, Hoechst 33342 staining experiment, were carried out to confirm the low cytotoxity and high biocompatibility. The confocal microscopy analysis results also revealed the increasing uptake of Cur@FA-PEI-HMTN by MCF-7 cells. The synthesized nanoparticles displayed great potential as drug nanovehicles with high biocompatibility.


Assuntos
Curcumina , Sistemas de Liberação de Medicamentos/métodos , Nanopartículas Metálicas , Titânio/química , Antioxidantes/química , Antioxidantes/farmacocinética , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Curcumina/química , Curcumina/farmacocinética , Curcumina/farmacologia , Preparações de Ação Retardada , Ácido Fólico , Células Hep G2 , Humanos , Células MCF-7 , Raios Ultravioleta
7.
Phys Chem Chem Phys ; 23(17): 10164-10173, 2021 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-33951125

RESUMO

Parameterizing an effective water model is a challenging issue because of the difficulty in maintaining a comprehensive balance among the diverse physical properties of water with a limited number of parameters. The advancement in machine learning provides a promising path to search for a reliable set of parameters. Based on the TIP4P water model, hence, about 6000 molecular dynamics (MD) simulations for pure water at 1 atm and in the range of 273-373 K are conducted here as the training data. The back-propagation (BP) neural network is then utilized to construct an efficient mapping between the model parameters and four crucial physical properties of water, including the density, vaporization enthalpy, self-diffusion coefficient and viscosity. Without additional time-consuming MD simulations, this mapping operation could result in sufficient and accurate data for high-population genetic algorithm (GA) to optimize the model parameters as much as possible. Based on the proposed parameterizing strategy, TIP4P-BG (a conventional four-site water model) and TIP4P-BGT (an advanced model with temperature-dependent parameters) are established. Both the water models exhibit excellent performance with a reasonable balance among the four crucial physical properties. The relevant mean absolute percentage errors are 3.53% and 3.08%, respectively. Further calculations on the temperature of maximum density, isothermal compressibility, thermal expansion coefficient, radial distribution function and surface tension are also performed and the resulting values are in good agreement with the experimental values. Through this water modeling example, the potential of the proposed data-driven machine learning procedure has been demonstrated for parameterizing a MD-based material model.

8.
Pharmazie ; 76(6): 249-255, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-34078518

RESUMO

Citri reticulatae pericarpium is a condiment, adding much flavor in Chinese food. Also it can be used to treat depression as a Traditional Chinese Medicine (TCM). The study here aimed to evaluate the antidepressant effect between the supercritical CO2 extract (SC-E) from Citri reticulatae pericarpium and the essential oil extracted by steam distillation (SD-E). And chemical compositions of SC-E were qualitatively analyzed by ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) and gas chromatography-mass spectrometry (GC-MS). Compared with SD-E, SC-E showed a stronger antidepressant-like effect in FST and TST mice. And it also decreased the content of monoamine oxidase (MAO) in the cerebral cortex of stressed mice. A total of 60 compounds were identified in SC-E. Among them, 28 compounds were characterized in UPLC-Q-TOF/MS analysis and all are polymethoxyflavones (PMFs). Three main compounds, 3,5,6,7,8,3',4'-heptamethoxyflavone, nobiletin and tangeretin, together account for 66.09% of the total relative peak area. 33 terpenes were identified by GC-MS analysis, such as D-limonene (12.34%), ß-elemene (8.86%), germacrene D (5.59%) and (Z, E)-α-farnesene (5.44%). Polymethoflavones and terpenes are the main constituents of SC-E responsible for its antidepressant-like effect. The study could stimulate further investigations into the antidepressant effects and mechanism of Citri reticulatae pericarpium.


Assuntos
Antidepressivos/farmacologia , Citrus , Medicamentos de Ervas Chinesas , Extratos Vegetais/farmacologia , Animais , Dióxido de Carbono , Citrus/química , Camundongos , Compostos Fitoquímicos/farmacologia
9.
Bull Environ Contam Toxicol ; 107(4): 577-584, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32166334

RESUMO

Plastics are ubiquitous in the environment and have become a hot topic in academic circles. Extensive studies have focused on analytical methods, source, abundance, transport, fate, degradation of plastics in the environment and threats to natural surroundings, wildlife or even human health. However, characteristics of plastic pollution, which are critical to understand this emerging problem, remain unknown up to now. Here, this paper reviews the major characteristics of plastic pollution in the environment to enhance present understanding of this issue. These characteristics, including diversity, persistence, global issues, combined pollution and threats to organisms and human health, are critically summarized in this work. Further, "plastic cycle" in the environment, namely, aquatic, atmospheric, and terrestrial system, is also discussed in this review. Finally, we highlight current challenges of plastic pollution posed to the public and also recommend the research trends in future work.


Assuntos
Plásticos , Poluentes Químicos da Água , Monitoramento Ambiental , Poluição Ambiental , Humanos , Poluentes Químicos da Água/análise
10.
Small ; 16(26): e2001494, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32510845

RESUMO

Persistent luminescence nanoparticles (PLNPs) with rechargeable near-infrared afterglow properties attract much attention for tumor diagnosis in living animals since they can avoid tissue autofluorescence and greatly improve the signal-to-background ratio. Using UV, visible light, or X-ray as excitation sources to power up persistent luminescence (PL) faces the challenges such as limited tissue penetration, inefficient charging capability, or tissue damage caused by irradiation. Here, it is proved that radiopharmaceuticals can efficiently excite ZnGa2 O4 :Cr3+ nanoparticles (ZGCs) for both fluorescence and afterglow luminescence via Cerenkov resonance energy transfer as well as ionizing radiation. 18 F-FDG, a clinically approved tumor-imaging radiopharmaceutical with a short decay half-life around 110 min, is successfully used as the internal light source to in vivo excite intravenously injected ZGCs for tumor luminescence imaging over 3 h. The luminescence with similar decay time can be re-obtained for multiple times upon injection of 18 F-FDG at any time needed with no health concern. It is believed this strategy can not only provide tumor luminescence imaging with high sensitivity, high contrast, and long decay time at desired time, but also guarantee the patients much less radiation exposure, greatly benefiting image-guided surgery in the future.


Assuntos
Luminescência , Nanopartículas , Neoplasias , Imagem Óptica , Compostos Radiofarmacêuticos , Animais , Humanos , Nanopartículas/química , Neoplasias/diagnóstico por imagem , Imagem Óptica/métodos , Radioatividade
11.
Opt Express ; 28(2): 2649-2660, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-32121949

RESUMO

The premise that long afterglow can be applied is its duration, and the persistent duration is closely related to the depth of the traps. Therefore, the stable deep traps are the key to obtain long persistent luminescence. Based on this, a strategy that X-ray excites high-gap phosphors to achieve long persistent luminescence is firstly proposed. Herein, rare earth (RE) ions doped YPO4 phosphor is adopted as the research object as RE ions can form stable and deeper defect centers or luminescent centers in high bandgap materials. Furthermore, the efficient method of enhancing persistent luminescence is designed so that introducing Tb3+ ions into YPO4:Sm3+ crystals forms tightly bound excitons, which modulates the depth of defect centers (Sm3+ ions), improving the afterglow behavior from Sm3+ ions for more than two days, which is approximately 14 times stronger than the afterglow of YPO4:Sm3+ phosphors itself. Finally, highly efficient in vivo deep tissue bioimaging was successfully achieved through mouse tail intravenous injection. The results indicate that the YPO4:Sm3+,Tb3+ phosphor possesses great promise in the field of in vivo imaging.


Assuntos
Imageamento Tridimensional , Luminescência , Substâncias Luminescentes/química , Metais Terras Raras/química , Animais , Sistemas Computacionais , Elementos da Série dos Lantanídeos/química , Camundongos , Espectrometria de Fluorescência , Temperatura , Térbio/química , Difração de Raios X
12.
J Sep Sci ; 43(12): 2380-2392, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32333498

RESUMO

The aerial parts of Polygonum chinense L. var. hispidum are one of the key herbs in Cantonese herbal tea, which is quite a common local beverage in LingNan area of China. Previous investigation has found that this herb possesses antioxidant activity and the ethyl acetate fraction of its ethanol extract shows the strongest antioxidant activity. However, little is known about its antioxidant chemical constituents. The aim of this research was to investigate the active constituents of this plant by identifying and characterizing the chemical profile in ethyl acetate fraction using ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry, which can provide characteristic ultraviolet absorption, accurate molecular weight, and diagnostic tandem mass spectrometry fragment ions. As a result, 85 compounds were identified including 22 flavonoids, 12 ellagic acids, 34 ellagitannins, 16 phenolic acids, and one phenolic amide. All the phenolic compounds identified in this work, especially ethyl gallate, geraniin, chebulagic acid, and quercitrin with the higher peak areas in the ultra high performance liquid chromatography with mass spectrometry chemical profile of this plant, could be the bioactive principles responsible for the antioxidant activity. These findings in the present study could benefit further studies involving the functions and chemicals of this plant, and provide scientific evidence for usage of Cantonese herbal tea.


Assuntos
Antioxidantes/análise , Medicamentos de Ervas Chinesas/análise , Componentes Aéreos da Planta/química , Polygonum/química , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas , Estrutura Molecular , Fatores de Tempo
13.
J Environ Sci (China) ; 88: 248-259, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31862066

RESUMO

Silver nanoparticles (AgNPs) are widely used in many consumer products, whereas their environmental behaviors in natural aquatic systems remain unknown, especially in natural brackish media. Therefore, it is urgent to investigate the environmental fate of AgNPs in natural brackish waters. Here, we investigated the stability of citrate-coated AgNPs in natural brackish water collected from 6 different sites with distinct salinities in the Xinglinwan Reservoir, located in Xiamen City, southeast China. The obtained results showed that AgNP colloids remained stable in low-salinity waters, which was mainly determined by the effects of dissolved organic matter (DOM) promoting the stability of the nanoparticles. However, the environmental fate of AgNPs in high-salinity waters was dominated by the salinity or ionic strength, especially the free ion concentrations of Cl-, SO42-, or S2-, resulting in rapid sedimentation and dissolution. In addition, both DOM and salinity contributed to the environmental behavior of AgNPs in moderate-salinity waters, ultimately resulting in either colloidal stability or sedimentation. Overall, these results may reveal that AgNPs remain relatively stable for a long period in low-salinity natural waters, and that the stability might gradually decrease as AgNPs are transferred from freshwaters through brackish waters and eventually end up in seawater along the bay. Our findings also further indicate that the toxicity and potential risks of AgNPs may present more serious threats to the environment and organisms in natural freshwaters than in natural estuarine systems or seawater.


Assuntos
Monitoramento Ambiental , Nanopartículas Metálicas , Prata , Poluentes Químicos da Água , China , Estuários , Água Doce , Água do Mar
14.
Bull Environ Contam Toxicol ; 103(2): 267-273, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31172221

RESUMO

The development of nanotechnology has drawn increased attention to the risks of nanoparticles (NPs). In this work, the near-infrared persistent luminescence imaging technique was used to track the biodistribution of NPs in vivo in zebrafish. Zebrafish were used as a vertebrate animal model to show NPs distribution and the effects of exposure. ZnGa2O4:Cr (ZGOC) was chosen as the probe in this work. In continuous exposure experiments, the results showed more particles accumulated in the intestines than in the gills in both groups. In both the gills and abdomen, the NPs contents were greater in the ZGOC-NH2-treated groups than in the ZGOC groups, and the NPs caused damage to the gills and intestines. Removal exposure experiments indicated that ZGOC and ZGOC-NH2 could be excreted from the body. The metabolism, excretion of NPs, the quantification and monitoring of NPs behavior in biological systems should be examined in further studies.


Assuntos
Nanopartículas/metabolismo , Poluentes Químicos da Água/farmacocinética , Peixe-Zebra/metabolismo , Animais , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/metabolismo , Medições Luminescentes , Nanopartículas/química , Nanopartículas/toxicidade , Imagem Óptica , Propriedades de Superfície , Distribuição Tecidual , Poluentes Químicos da Água/química , Poluentes Químicos da Água/toxicidade
15.
Nanotechnology ; 29(40): 405102, 2018 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-30020084

RESUMO

The aggregation of nanoparticles (NPs) on the cell membrane is crucial for the cellular uptake process and has important biological implications in protein-membrane interactions. In this paper, we systematically investigate how the aggregation is regulated by the mechanical properties of the NP-membrane system, including the membrane tension, and the size and shape of the NPs. Results show that when NPs aggregate parallel to the cell membrane, increasing the membrane tension will modulate the membrane-mediated interaction between the NPs from attractive to attractive-repulsive and finally to purely repulsive. In contrast, the membrane-mediated interaction is attractive and independent of the membrane tension when the NPs aggregate to a tubular configuration. For the aggregation of NPs of different sizes, the large-size NP is wrapped to a greater extent than the small-size NP. For the aggregation of nonspherical NPs, low aspect ratio and weak NP-membrane adhesion strength lead to the side-to-side configuration, whereas a system with a high aspect ratio and strong NP-membrane adhesion strength prefers the tip-to-tip configuration. Importantly, NPs of different sizes and anisotropic shapes are found to facilitate the aggregation process by reducing the energy barrier that should be overcome during the aggregation. The results reveal the mechanism of the aggregation of NPs on the cell membrane and provide guidelines to the design of NP-based drug delivery systems.


Assuntos
Membrana Celular/química , Nanopartículas/química , Fenômenos Biomecânicos , Sistemas de Liberação de Medicamentos , Tamanho da Partícula , Propriedades de Superfície
16.
Nanotechnology ; 29(2): 025707, 2018 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-29226852

RESUMO

Polar water molecules exhibit extraordinary phenomena under nanoscale confinement. Through the application of an electric field, a water-filled carbon nanotube (CNT) that has been successfully fabricated in the laboratory is expected to have distinct responses to the external electricity. Here, we examine the effect of electric field direction on the mechanical property of water-filled CNTs. It is observed that a longitudinal electric field enhances, but the transverse electric field reduces the elastic modulus and critical buckling stress of water-filled CNTs. The divergent effect of the electric field is attributed to the competition between the axial and circumferential pressures induced by polar water molecules. Furthermore, it is notable that the transverse electric field could result in an internal pressure with elliptical distribution, which is an effective and convenient approach to apply nonuniform pressure on nanochannels. Based on pre-strained water-filled CNTs, we designed a nanoscale trigger with an evident and rapid height change initiated by switching the direction of the electric field. The reported finding provides a foundation for an electricity-controlled property of nanochannels filled with polar molecules and provides an insight into the design of nanoscale functional devices.

17.
Anal Bioanal Chem ; 410(18): 4331-4341, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29732497

RESUMO

High resolution has been constantly pursued in both preparative and analytical chromatography. Chromatographic media are a key factor during the entire separation process. Tailor-made chromatographic media have gained more attention because of their adjustable structure appropriate for application. Uniform polysaccharide composite microspheres were prepared with a mixture of agarose and dextran solution by membrane emulsification technique for the first time. Their pore structure was deliberately regulated by adjusting both the polysaccharide composition and the molecular weight of dextran. Compared with pure agarose microspheres, polysaccharide composite microspheres had a higher separation resolution and their separation range was controllable. By increasing agarose concentration and decreasing dextran concentration at the same time during the preparation of composite microspheres, the mean pore size increased first and then decreased later, and also the pore size distribution became narrower. By increasing the molecular weight of dextran, the pores became smaller with a narrower pore size distribution. Microspheres with a composition of 10% agarose/2% dextran T40 or 8% agarose/4% dextran T150 showed a higher separation resolution for proteins within range of low molecular weight. Furthermore, the mechanical strength of this composite microsphere was improved by adjusting its composition. Atomic force microscope (AFM) results showed that pores were distributed evenly on both the surface and the inner part of microspheres, beneficial for the passage of biomolecules. These novel uniform polysaccharide composite microspheres have great potential for high-resolution bioseparation. Graphical abstract ᅟ.

18.
J Asian Nat Prod Res ; 20(11): 1055-1063, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30130142

RESUMO

Costunolide and dehydrocostuslactone are the main active ingredients of Radix Aucklandiae (RA). An accurate and sensitive LC-MS/MS method was established to simultaneously determine contents of costunolide and dehydrocostuslactone in plasma. There were significant differences in pharmacokinetic parameters (AUC0-t, Cmax,1, Cmax,2, Tmax,1, Vd, and CL) of costunolide and dehydrocostuslactone between RA group and costunolide group or dehydrocostuslactone group. The relative bioavailability of costunolide or dehydrocostuslactone of RA extract was improved. As compared to normal group, the Tmax,2 values of dehydrocostuslactone of RA in gastric ulcer group were prolonged, while the Cmax,1, Cmax,2, and AUC0-t values decreased.


Assuntos
Asteraceae/química , Lactonas/farmacocinética , Extratos Vegetais/farmacocinética , Sesquiterpenos/farmacocinética , Úlcera Gástrica/tratamento farmacológico , Administração Oral , Animais , Lactonas/administração & dosagem , Masculino , Extratos Vegetais/química , Raízes de Plantas/química , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Sesquiterpenos/administração & dosagem
19.
Z Naturforsch C J Biosci ; 73(3-4): 107-116, 2018 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-28787276

RESUMO

Di-Wu-Yang-Gan Granules is a Traditional Chinese Medicine prescription used for the treatment of HBeAg-negative chronic hepatitis B patients in China. It consists of five commonly used Chinese herbs. However, the chemical constituents of the whole prescription had not been clarified yet. Hence, in this study, the chemical profiling of Di-Wu-Yang-Gan Granules was explored by ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry, which can provide accurate molecular weight within 5-ppm error and sufficient MS/MS fragment ions without the need for precursor ion selection. As a result, 116 compounds were identified, including lignans, triterpenesaponins, flavonoids, coumarins, iridoids, nortriterpenoids, phenolic acids, and sesquiterpenes. All compounds were further assigned to the individual herbs. In conclusion, this established method was reliable and effective for the separation and identification of the constituents in Di-Wu-Yang-Gan Granules. The findings are beneficial for quality control of the prescription during production and provide helpful chemical information for exploring its efficacy and the mechanism of action. The fragmentation regularity summarized in this study also provided important information for the rapid identification of the chemical composition in herbal medicines or their prescription.


Assuntos
Cromatografia Líquida/métodos , Medicamentos de Ervas Chinesas/química , Espectrometria de Massas/métodos , Cumarínicos/análise , Flavonoides/análise , Iridoides/análise , Lignanas/análise , Fenóis/análise , Sesquiterpenos/análise
20.
Molecules ; 23(5)2018 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-29751555

RESUMO

Three new highly oxygenated (2⁻4), and two known (1 and 5) germacranolides, were isolated from the whole plant of Carpesium divaricatum. The planar structures and relative configurations of the new compounds were determined by detailed spectroscopic analysis. The absolute configuration of 1 was established using the circular dichroism (CD) method and X-ray diffraction, and the stereochemistry of the new compounds 2⁻4 were determined using similar CD spectra with 1. The new compound 2 and the known compound 5 exhibited potent cytotoxicity against hepatocellular cancer (Hep G2) and human cervical cancer (HeLa) cells, superior to those of the positive control cis-platin.


Assuntos
Asteraceae/química , Sesquiterpenos de Germacrano/química , Sesquiterpenos de Germacrano/farmacologia , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Dicroísmo Circular , Humanos , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Conformação Molecular , Estrutura Molecular , Sesquiterpenos de Germacrano/isolamento & purificação , Relação Estrutura-Atividade , Difração de Raios X
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