Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 28
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Int Heart J ; 64(2): 128-136, 2023 Mar 31.
Artículo en Inglés | MEDLINE | ID: mdl-36927935

RESUMEN

This study aimed to investigate the clinical characteristics and major adverse cardiovascular events (MACEs) of Chinese patients with premature acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). This study was a secondary retrospective analysis involving 2114 ACS patients undergoing PCI at a single center in China. The patients were divided into two groups according to age (premature ACS group: ≤ 55 years in men, ≤ 65 years in women; nonpremature ACS group: > 55 years in men, > 65 years in women). The primary endpoint was all-cause death, and the secondary endpoint was a composite of all-cause death, nonfatal myocardial infarction, nonfatal stroke, target vessel revascularization, and recurrent angina at follow-up, defined as MACEs. The incidence of all-cause death and MACEs was significantly lower in the premature than in the nonpremature ACS group (P < 0.001). Female sex, higher triglyceride levels, and higher low-density lipoprotein cholesterol levels were identified as independent risk factors that accelerated the development of ACS, whereas higher high-density lipoprotein cholesterol levels were identified as protective factors. Furthermore, in patients with premature ACS, non-ST-elevation ACS, cardiac insufficiency, multivessel disease, and left main lesion were risk factors for MACEs. Younger individuals, especially females, are advised to undergo early screening for the risk factors of premature ACS. Primary prevention of dyslipidemia should be more aggressively promoted at a young age. For premature ACS patients undergoing PCI, strengthened management and regular re-examinations are necessary to avoid adverse cardiovascular events as much as possible.


Asunto(s)
Síndrome Coronario Agudo , Intervención Coronaria Percutánea , Femenino , Humanos , Masculino , Persona de Mediana Edad , Síndrome Coronario Agudo/diagnóstico , Síndrome Coronario Agudo/epidemiología , Síndrome Coronario Agudo/etiología , Colesterol , Pueblos del Este de Asia , Estudios Retrospectivos , Resultado del Tratamiento , Anciano
2.
J Am Chem Soc ; 144(30): 13729-13739, 2022 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-35876689

RESUMEN

We are currently witnessing the dawn of hydrogen (H2) economy, where H2 will soon become a primary fuel for heating, transportation, and long-distance and long-term energy storage. Among diverse possibilities, H2 can be stored as a pressurized gas, a cryogenic liquid, or a solid fuel via adsorption onto porous materials. Metal-organic frameworks (MOFs) have emerged as adsorbent materials with the highest theoretical H2 storage densities on both a volumetric and gravimetric basis. However, a critical bottleneck for the use of H2 as a transportation fuel has been the lack of densification methods capable of shaping MOFs into practical formulations while maintaining their adsorptive performance. Here, we report a high-throughput screening and deep analysis of a database of MOFs to find optimal materials, followed by the synthesis, characterization, and performance evaluation of an optimal monolithic MOF (monoMOF) for H2 storage. After densification, this monoMOF stores 46 g L-1 H2 at 50 bar and 77 K and delivers 41 and 42 g L-1 H2 at operating pressures of 25 and 50 bar, respectively, when deployed in a combined temperature-pressure (25-50 bar/77 K → 5 bar/160 K) swing gas delivery system. This performance represents up to an 80% reduction in the operating pressure requirements for delivering H2 gas when compared with benchmark materials and an 83% reduction compared to compressed H2 gas. Our findings represent a substantial step forward in the application of high-density materials for volumetric H2 storage applications.

3.
Catheter Cardiovasc Interv ; 100(4): 674-678, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35920813

RESUMEN

Annular rupture is a rare and dreaded complication of transcatheter aortic valve replacement (TAVR) and even rarer when caused by predilatation balloon aortic valvuloplasty. This complication often presents as sudden cardiac tamponade with hypotension and requires urgent intervention. The traditional rescue strategy for patients with annular rupture is emergency surgical repair. However, the mortality rate is still high, considering that most patients who undergo TAVR are not candidates for conventional cardiac surgery. Therefore, there is a need for additional emergency treatment strategies to decrease mortality. This report describes a case of predilatation-induced annular rupture during TAVR that was successfully sealed at the rupture site by valve implantation. This case suggests that continuing with valve deployment may be a successful treatment for predilatation-induced annular rupture during TAVR.


Asunto(s)
Estenosis de la Válvula Aórtica , Valvuloplastia con Balón , Prótesis Valvulares Cardíacas , Reemplazo de la Válvula Aórtica Transcatéter , Válvula Aórtica/diagnóstico por imagen , Válvula Aórtica/cirugía , Estenosis de la Válvula Aórtica/diagnóstico por imagen , Estenosis de la Válvula Aórtica/cirugía , Valvuloplastia con Balón/efectos adversos , Humanos , Diseño de Prótesis , Reemplazo de la Válvula Aórtica Transcatéter/efectos adversos , Resultado del Tratamiento
4.
Exp Cell Res ; 391(2): 111983, 2020 06 15.
Artículo en Inglés | MEDLINE | ID: mdl-32268136

RESUMEN

OBJECTIVE: To explore the effects of breast cancer (BC)-derived exosomes on invasion and migration of BC cells. METHODS: Exosomes (Exo-MA, Exo-M7, Exo-M1) were extracted from normal breast epithelial cells (MCF-10A), BC cells (MCF-7/MDA-MB-231) and BC cells with miR-146a overexpression or knockdown using multi-step differential centrifugation. Morphologies and sizes of exosomes were observed by transmission electron microscope (TEM) and particle size analysis respectively. BC mouse models were injected with DIR labeled Exo-MA, Exo-M7 or Exo-M1. The epithelial-mesenchymal transition (EMT) in BC cells was determined by PCR and Western blot. PKH67 labeled Exo-MA, Exo-M7 and Exo-M1 were incubated with NFs or MCF-7 to measure the activation of CAFs. Cell invasion and migration abilities were determined by scratch test and Transwell assay. RESULTS: Exo-MA, Exo-M7, Exo-M1 were successfully extracted with positive expressions of Alix, CD63 and TSG101. Contents of Ki67, N-cadherin, Vimentin and Snail-1 were increased but E-cadherin was decreased, compared to Exo-MA group. Exo-M7 or Exo-M1 could increase BC cell proliferation and enhance EMT in nude mouse. Exo-M7 and Exo-M1 could accelerate the transformation of NFs into CAFs and promote the recruitment of CAFs in MCF-7. Transfection of miR-146a could promote the transformation of NFs into CAFs and promote cell invasion and migration of MCF-7 cells. As a target gene of miR-146a, TXNIP could inhibit the activation of CAFs. miR-146a overexpression or TXNIP silence enhance the activation of Wnt signal pathway. CONCLUSION: BC-derived exosomes promote the activation of CAFs through miR-146a/TXNIP axis to activate Wnt pathway, which in turn enhances invasion and metastasis of BC cells.


Asunto(s)
Biomarcadores de Tumor/metabolismo , Neoplasias de la Mama/patología , Fibroblastos Asociados al Cáncer/patología , Exosomas/patología , Regulación Neoplásica de la Expresión Génica , MicroARNs/genética , Microambiente Tumoral/genética , Animales , Apoptosis , Biomarcadores de Tumor/genética , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Fibroblastos Asociados al Cáncer/metabolismo , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Movimiento Celular , Proliferación Celular , Exosomas/genética , Exosomas/metabolismo , Femenino , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Invasividad Neoplásica , Metástasis de la Neoplasia , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de Xenoinjerto
5.
Angew Chem Int Ed Engl ; 59(40): 17600-17606, 2020 09 28.
Artículo en Inglés | MEDLINE | ID: mdl-32589318

RESUMEN

To gain insight into chiral recognition in porous materials we have prepared a family of fourth generation chiral metal-organic frameworks (MOFs) that have rigid frameworks and adaptable (flexible) pores. The previously reported parent material, [Co2 (S-mandelate)2 (4,4'-bipyridine)3 ](NO3 )2 , CMOM-1S, is a modular MOF; five new variants in which counterions (BF4- , CMOM-2S) or mandelate ligands are substituted (2-Cl, CMOM-11R; 3-Cl, CMOM-21R; 4-Cl, CMOM-31R; 4-CH3 , CMOM-41R) and the existing CF3 SO3- variant CMOM-3S are studied herein. Fine-tuning of pore size, shape, and chemistry afforded a series of distinct host-guest binding sites with variable chiral separation properties with respect to three structural isomers of phenylpropanol. Structural analysis of the resulting crystalline sponge phases revealed that host-guest interactions, guest-guest interactions, and pore adaptability collectively determine chiral discrimination.

6.
J Am Chem Soc ; 140(39): 12545-12552, 2018 Oct 03.
Artículo en Inglés | MEDLINE | ID: mdl-30196697

RESUMEN

Hydrolytically stable adsorbents are needed for water vapor sorption related applications; however, design principles for porous materials with tunable water sorption behavior are not yet established. Here, we report that a platform of fourth-generation metal-organic materials (MOMs) with rigid frameworks and self-switching pores can adapt their pores to modulate water sorption. This platform is based upon the hydrolytically stable material CMOM-3S, which exhibits bnn topology and is composed of rod building blocks based upon S-mandelate ligands, 4,4-bipyridine ligands, and extraframework triflate anions. Isostructural variants of CMOM-3S were prepared using substituted R-mandelate ligands and exhibit diverse water vapor uptakes (20-67 cm3/g) and pore filling pressures ( P/ P0, 0.55-0.75). [Co2( R-4-Cl-man)2(bpy)3](OTf) (33R) is of particular interest because of its unusual isotherm. Insight into the different water sorption properties of the materials studied was gained from analysis of in situ vibrational spectra, which indicate self-switching pores via perturbation of extraframework triflate anions and mandelate linker ligands to generate distinctive water binding sites. Water vapor adsorption was studied using in situ differential spectra that reveal gradual singlet water occupancy followed by aggregation of water clusters in the channels upon increasing pressure. First-principles calculations identified the water binding sites and provide structural insight on how adsorbed water molecules affect the structures and the binding sites. Stronger triflate hydrogen bonding to the framework along with significant charge redistribution were determined for water binding in 33R. This study provides insight into a new class of fourth-generation (self-switching pores) MOM and the resulting effect upon water vapor sorption properties.

7.
Chemistry ; 24(15): 3754-3759, 2018 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-29194823

RESUMEN

The applications of three-dimensional superstructures that consist of metal-organic framework (MOF) crystals are promising, but limited by spatial control over the crystallization process. Here a hydrophobic hierarchical metal-organic framework (HZIF-8) containing unusual micro-, meso-, and macropores was designed and synthesized by a template strategy, in which the polystyrene (PS) not only acted as the template to construct the macropores, but also modified the hydrophilic crystal surface of ZIF-8. When used as adsorbent for liquid oil/water separation, HZIF-8 demonstrated significantly enhanced oil adsorption performance while maintaining very low water uptake.

8.
Guang Pu Xue Yu Guang Pu Fen Xi ; 36(10): 3303-7, 2016 Oct.
Artículo en Zh | MEDLINE | ID: mdl-30246970

RESUMEN

Silicon is not a natural component of gasoline but it can cause silica deposition in vehicle combustion system which may lead to severe engine failure. Silicon is present in gasoline in different chemical forms. The analysis of oil products by directly measuring under organic phase through inductively coupled plasma optical emission spectrometry (ICP-OES) is becoming a widely accepted approach as it is found to be simple and fast. The work focused on the influence of the sample nebulizer systems to different silicon chemical forms by ICP-OES. For a sample introduction system consisting of micronebulizer coupled to a cyclonic spray chamber, the results indicated that the ICP-OES signals depended strongly on the silicon chemical forms, and the higher emission intensities have been attributed to the compound volatility. The variability of the signals induced by the different silicon compounds was less significant for the same nebulizer system with a temperature control device. Nevertheless, the interferences were not effectively mitigated. Nevertheless, direct injection high efficiency nebulizer (DIHEN) introduced in the present work can effectively mitigate the interferences of different silicon chemical forms, is suitable for the determination of silicon in gasoline. The quantitative method with the potential DIHEN nebulizer system showed good linearity and the recoveries ranged from 92.8%~108.7%, the limit of detection was 0.05 mg·kg-1. The relative standard deviation (RSD) was between 1.05% and 4.63%. Compared with the microwavedigestion method, the proposed method was found to be highly simple, rapid, sensitive and accurate, which has foreseen a promising application for silicon determination in gasoline.

9.
J Am Chem Soc ; 137(38): 12203-6, 2015 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-26355993

RESUMEN

Two lanthanide zeolite-like metal-organic frameworks (Ln-ZMOFs) with rho topology, Tb-ZMOF and Eu-ZMOF, were constructed by self-assembly of a 4-connected lanthanide molecular building block and a bipyridine-dicarboxylate ligand. Varying the Tb(3+) and Eu(3+) ratio during synthesis afforded three mixed-crystal isostructural MZMOFs with variable Eu:Tb stoichiometry. Fluorescence studies revealed that a methanol suspension of one of these mixed crystals, MZMOF-3, exhibits selective detection of lysophosphatidic acid (LPA), a biomarker for ovarian cancer and other gynecologic cancers. Linear correlation between the integrated fluorescence intensity and the concentration of LPA was observed, enabling quantitative analysis of LPA in physiologically relevant ranges (1.4-43.3 µM). MZMOF-3 therefore has the potential to act as a self-referencing and self-calibrating fluorescent indicator for LPA.


Asunto(s)
Biomarcadores de Tumor/análisis , Colorantes Fluorescentes/química , Neoplasias de los Genitales Femeninos/diagnóstico , Lisofosfolípidos/análisis , Compuestos Organometálicos/química , Neoplasias Ováricas/diagnóstico , Femenino , Humanos , Elementos de la Serie de los Lantanoides/química , Estructura Molecular , Zeolitas/química
10.
J Am Chem Soc ; 137(37): 12045-9, 2015 Sep 23.
Artículo en Inglés | MEDLINE | ID: mdl-26343355

RESUMEN

An enantiomeric pair of chiral metal-organic materials (CMOMs) based upon mandelate (man) and 4,4'-bipyridine (bpy) ligands, [Co2(S-man)2(bpy)3](NO3)2·guest (1S·guest) and [Co2(R-man)2(bpy)3](NO3)2·guest (1R·guest), have been prepared. The cationic frameworks exhibit one-dimensional chiral channels with dimensions of 8.0 Å × 8.0 Å. The pore chemistry is such that chiral surfaces lined with nitrate anions and phenyl groups create multiple binding sites for guest and/or solvent molecules. The performance of 1S and 1R with respect to resolution of racemic mixtures of 1-phenyl-1-propanol (PP) was studied by varying time, temperature, and the use of additives. Selectivity toward PP was determined by chiral HPLC with ee values of up to 60%. The binding sites and host-guest interactions were investigated through single-crystal X-ray structural analyses of guest-exchanged 1S and 1R. Crystallographically observed structural changes (e.g., the absolute configurations of the three PP binding sites switch from R, R, and S to R, R, and R/S) correlate with experimentally observed ee values of 33% and 60% for variants of 1S that contain PP and different solvent molecules, 1S·PPex and 1S·PPex', respectively. The fact that manipulation of guest solvent molecules, which in effect serve as cofactors, can modify chiral sites and increase enantioselectivity is likely to aid in the design of more effective CMOMs and processes for chiral separations.

11.
J Am Chem Soc ; 137(49): 15406-9, 2015 Dec 16.
Artículo en Inglés | MEDLINE | ID: mdl-26606156

RESUMEN

Chiral variants of the prototypal metal-organic framework MOF-5, Λ-CMOF-5 and Δ-CMOF-5, have been synthesized by preparing MOF-5 in the presence of L-proline or D-proline, respectively. CMOF-5 crystallizes in chiral space group P213 instead of Fm3̅m as exhibited by MOF-5. The phase purity of CMOF-5 was validated by single-crystal and powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, N2 adsorption, microanalysis, and solid-state vibrational circular dichroism. CMOF-5 undergoes a reversible single crystal-to-single crystal phase change to MOF-5 when immersed in a variety of organic solvents, although N-methyl-2-pyrrolidone (NMP) does not induce loss of chirality. Indeed, MOF-5 undergoes chiral induction when immersed in NMP, affording racemic CMOF-5.


Asunto(s)
Compuestos Organometálicos/síntesis química , Polímeros/síntesis química , Compuestos Organometálicos/química , Polímeros/química , Estereoisomerismo , Difracción de Rayos X
12.
Inorg Chem ; 54(5): 2310-4, 2015 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-25695730

RESUMEN

A ligand design approach, which requires rational design of ligand based on the knowledge of specific target, was applied for the synthesis of two interesting and robust MOFs 1 and 2 containing unusual several types of copper(II) secondary building units (SBUs). Thanks to unsaturated metal centers (UMCs) and azo group, microporous material 1 exhibited not only high CO2 uptake but also an impressive selective adsorption of CO2 over CH4 and N2. Moreover, a high H2 uptake of 1 was also observed.

13.
Guang Pu Xue Yu Guang Pu Fen Xi ; 34(12): 3406-10, 2014 Dec.
Artículo en Zh | MEDLINE | ID: mdl-25881448

RESUMEN

A new method was studied for the analysis of chlorine in gasoline by inductively coupled plasma atomic emission spectrometry (ICP-AES). Samples werediluted 1+4(φ) with kerosene. The intense spectral line for chlorine (134.724 nm) was used. In order to eliminate carbon and maintain stable plasma, small amounts of oxygen (0.050 L · min(-1)) were added to the auxiliary gas. The instrumental main condition was optimized in terms of effects of generator power, nebulizer gas flow, auxiliary gas flow, and oxygen flow on SBR for chlorine. Standard addition method was used to compensate matrix effect and signal drift. The recovery for spiking gasoline samples and the limit of detection were in the range of 96.6%~103.9% and 0.27 mg · L(-1) respectively. The relative standard deviation (RSD) was between 1.57% and 4.49%. Compared with microcoulometry, the analysis results of organic chlorine were basically the same. Moreover, chlorine content, including organic chlorine and inorganic chloride was determined by ICP-AES. The proposed method had the advantages of simplicity, speediness and sensitivity, and expanded the ICP-AES application in non-metals especially halogen elements. It can be used for the analysis of chlorine in gasoline and provides technical support for quality evaluation.

14.
Medicine (Baltimore) ; 101(45): e31724, 2022 Nov 11.
Artículo en Inglés | MEDLINE | ID: mdl-36397406

RESUMEN

Several epidemiological studies have shown a clear inverse relationship between serum levels of high-density lipoprotein cholesterol (HDL-C) and the risk of atherosclerotic cardiovascular disease (ASCVD), even at low-density lipoprotein cholesterol levels below 70 mg/dL. There is much evidence from basic and clinical studies that higher HDL-C levels are beneficial, whereas lower HDL-C levels are detrimental. Thus, HDL is widely recognized as an essential anti-atherogenic factor that plays a protective role against the development of ASCVD. Percutaneous coronary intervention is an increasingly common treatment choice to improve myocardial perfusion in patients with ASCVD. Although drug-eluting stents have substantially overcome the limitations of conventional bare-metal stents, there are still problems with stent biocompatibility, including delayed re-endothelialization and neoatherosclerosis, which cause stent thrombosis and in-stent restenosis. According to numerous studies, HDL not only protects against the development of atherosclerosis, but also has many anti-inflammatory and vasoprotective properties. Therefore, the use of HDL as a therapeutic target has been met with great interest. Although oral medications have not shown promise, the developed HDL infusions have been tested in clinical trials and have demonstrated viability and reproducibility in increasing the cholesterol efflux capacity and decreasing plasma markers of inflammation. The aim of the present study was to review the effect of HDL on stent biocompatibility in ASCVD patients following implantation and discuss a novel therapeutic direction of HDL infusion therapy that may be a promising candidate as an adjunctive therapy to improve stent biocompatibility following percutaneous coronary intervention.


Asunto(s)
Aterosclerosis , Intervención Coronaria Percutánea , Humanos , Lipoproteínas HDL , Reproducibilidad de los Resultados , Stents/efectos adversos , HDL-Colesterol , Aterosclerosis/tratamiento farmacológico
15.
Cell Physiol Biochem ; 27(3-4): 233-42, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21471712

RESUMEN

Deltonin, a steroidal saponin, isolated from Dioscorea zingiberensis Wright (DZW), has shown high-cytotoxic activity in cancer cells. However, its mechanisms and in vivo anti-cancer effects remain unknown. In the present study, we evaluated the effects and explored the anti-tumor mechanisms of deltonin on a panel of colon cancer cell lines and in a mouse model of murine colon cancer C26. Deltonin had more cytotoxic effect on C26 cells than 5-fluorouracil had, promoting dramatic G2-M phase arrest and apoptosis in C26 cells in a concentration-dependent manner; oral administration of deltonin significantly inhibited the tumor growth and prolonged survival of the tumor bearing mice. The deltonin treatment caused a noticeable apoptosis in tumor tissue, which associated with increased levels of Bax, activated caspase-3, caspase-9, and cleaved poly (ADPribose) polymerase, decreased pro-caspase-8, pro-caspase-9, Bcl-2 expression levels and extracellular signal-regulated kinase-1/2 activity; and dose-dependently inhibit angiogenesis. In conclusion, the findings in this study demonstrated that deltonin is an effective natural agent for cancer therapy, which may be mediated, in part, by induction of apoptosis, as well as involve mitogen-activated protein kinase pathways, and inhibition of angiogenesis.


Asunto(s)
Inhibidores de la Angiogénesis/uso terapéutico , Apoptosis/efectos de los fármacos , Neoplasias del Colon/tratamiento farmacológico , Neovascularización Patológica/tratamiento farmacológico , Espirostanos/uso terapéutico , Inhibidores de la Angiogénesis/química , Animales , Caspasa 3/metabolismo , Caspasa 8/metabolismo , Caspasa 9/metabolismo , Línea Celular Tumoral , Neoplasias del Colon/irrigación sanguínea , Modelos Animales de Enfermedad , Humanos , Masculino , Ratones , Ratones Endogámicos BALB C , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Molécula-1 de Adhesión Celular Endotelial de Plaqueta/inmunología , Molécula-1 de Adhesión Celular Endotelial de Plaqueta/metabolismo , Poli(ADP-Ribosa) Polimerasas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Saponinas/uso terapéutico , Espirostanos/química , Proteína X Asociada a bcl-2/metabolismo
16.
Zhonghua Yi Xue Za Zhi ; 91(25): 1746-8, 2011 Jul 05.
Artículo en Zh | MEDLINE | ID: mdl-22093731

RESUMEN

OBJECTIVE: To investigate the methods and efficacy of neuroendoscopic operation in the treatment of tethered spinal cord syndrome (TSCS). METHODS: A total of 21 cases were recruited. There were 13 males and 8 females with an average age of 12.5 years old. TSCS was diagnosed by magnetic resonance imaging (MRI). They were operated under neuroendoscope. RESULTS: No complication was found during a follow-up period of 0.5 - 3 years. The symptoms improved in 18 cases. Neither obvious improvement nor aggravation was found in 3 cases. The total effective rate was 85.71%. CONCLUSION: Neuroendoscopic treatment of TSCS is both safe and effective.


Asunto(s)
Defectos del Tubo Neural/cirugía , Neuroendoscopía , Procedimientos Neuroquirúrgicos/métodos , Adolescente , Adulto , Niño , Preescolar , Femenino , Humanos , Masculino , Adulto Joven
17.
ACS Appl Mater Interfaces ; 12(31): 35120-35131, 2020 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-32648440

RESUMEN

This work reports on a simple and general strategy for continuous fabrication of self-propelled micromotors with photocatalytic metal-organic frameworks (MOFs) for enhanced synergistic degradation of organic contaminants. With emulsion microdroplets from microfluidics as templates, uniform porous micromotors decorated with Fe3O4@Ag nanoparticles (Fe3O4@AgNPs) at the bottom and zeolitic imidazolate framework-8@ZnO nanoparticles (ZIF-8@ZnONPs) on the surface can be synthesized. The spatial location of ZIF-8@ZnONPs and Fe3O4@AgNPs in micromotors is accurately controlled in one step via their directional migration in the confined microspace of emulsion droplets driven by interfacial energy and magnetic field. The nanoengines Fe3O4@AgNPs enable asymmetric decomposition of H2O2 for bubble-propelled motion and easy magnetic recycling of the micromotor. The porous structures of micromotors provide a large surface area, benefiting decoration of Fe3O4@AgNPs and their contact with H2O2 for promoting bubble generation and reduced micromotor weight for promoting bubble-propelled motion. The nanophotocatalysts ZIF-8@ZnONPs allow enrichment of organic contaminant molecules via adsorption for efficient photocatalytic degradation. With synergistic coupling of the photocatalysis of ZIF-8@ZnONPs and advanced oxidation of the H2O2/UV system, the micromotors with bubble-propelled motion for improved mixing can achieve enhanced degradation of organic contaminants via dual synergistic degradation mechanisms. As highlighted by degradation of rhodamine B, the micromotors exhibit the highest degradation performance as compared to control groups with a single degradation mechanism and with dual degradation mechanisms but without self-propelled motion. This simple fabrication strategy is general and can be flexibly extended to other MOF materials, which may open up new avenues for developing advanced MOF-integrated micromotors for myriad applications.

18.
Guang Pu Xue Yu Guang Pu Fen Xi ; 29(12): 3335-8, 2009 Dec.
Artículo en Zh | MEDLINE | ID: mdl-20210164

RESUMEN

The present paper investigates the influence of solvent purity on the test of three-dimensional fluorescence spectra, determines the process of its pre-purification, and studies the influence of the concentrations on the three-dimensional fluorescence characteristic indexes such as the characteristic peaks position, fluorescence intensity (F), and ratio (R) of fluorescence intensity when the phenomena of fluorescence quenching won't appear. The result shows that the concentration affects the value F and value R largely but its effect on the relative peak intensity (R(s)) is relatively small. Different crude oils has different value R(s). According to those characteristics, this paper presents that the value R(s) can be used as a new characteristic index for identification of crude oil. This conclusion was confirmed by testing many crude oils stably and reliably from different areas with their concentrations at 5 mg x L(-1). This method can be applied to identify most crude oils preliminary and further accurate analysis can be carried out together with other index.

19.
ACS Appl Mater Interfaces ; 11(49): 46241-46250, 2019 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-31739661

RESUMEN

Microhelices with unique three-dimensional (3D) helical structures have attracted great attention due to applications in various fields, especially magnetic microhelices can be applied as microrobots for removal of clogging substance in microchannels, cargo transport, cell manipulation, and so on. Here, a facile and flexible strategy is developed to controllably fabricate microhelices with droplet microfluidics. On-flow fabrication of microhelices is simply achieved by generating monodisperse droplets first, transforming the spherical droplets into helical templates subsequently due to the liquid rope coiling effect, followed by polymerizing monomers in the templates via on-line UV irradiation and then degrading the shells of helical fibers. Benefitting from the flexible controllability of microfluidics, the morphologies of microhelices can be precisely controlled by adjusting the flow rates of fluids and the structures of microfluidic devices. Functional microhelices can be easily prepared by introducing functional components or elements into inner fluids. By introducing magnetic nanoparticles into inner fluids, magnetic microhelices are easily fabricated as microrobots that featured with magnetic-field-driven corkscrew-like motion for efficient cargo transport and removal of clogging substance in microchannels. This novel microfabrication method allows a precise morphological control and easy functionalization of microhelices, providing a flexible and versatile strategy for fabricating designer functional microhelices for diverse applications.

20.
Zhonghua Wai Ke Za Zhi ; 46(8): 598-601, 2008 Apr 15.
Artículo en Zh | MEDLINE | ID: mdl-18844056

RESUMEN

OBJECTIVE: To summarize the experience of surgical therapy in a series of 438 patients with intracranial aneurysms. METHODS: A retrospective analysis was made on the clinical data of 438 patients, in terms of the perioperative management, timing of surgery, surgical skills, and The HUNT-HESS grade. RESULTS: 438 patients with 476 aneurysms underwent microsurgery, in which 450 aneurysms were clipped, 14 were wrapped, 8 were isolated,4 were cut. 32 aneurysms were ruptured (6.72%) during the operation. The relation between Hunt-Hess scale and mortality is significant postpone operation (> or =7 d) has got a better curative effect than the early. CONCLUSIONS: Microsurgical treatment is a confirmed effective method with intracranial aneurysms. The higher of HUNT-HESS grade will result to the worse clinical outcome.


Asunto(s)
Aneurisma Intracraneal/cirugía , Microcirugia/métodos , Adolescente , Adulto , Anciano , Niño , Femenino , Humanos , Aneurisma Intracraneal/mortalidad , Masculino , Persona de Mediana Edad , Procedimientos Neuroquirúrgicos/métodos , Pronóstico , Estudios Retrospectivos , Resultado del Tratamiento
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA