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1.
Sleep Breath ; 26(3): 1265-1275, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35038086

RESUMEN

PURPOSE: Allergic rhinitis (AR) is an independent risk factor for sleep disorders in children, including abnormal sleep behaviors. We investigated the occurrence of abnormal sleep behaviors in children with AR to determine indoor environmental risk factors affecting sleep. METHODS: This case-control study collected the sleep status and characteristics of the indoor environment of children aged 3-14 years with and without AR using a questionnaire. The differences between the two groups were compared using the Mann-Whitney U test, chi-square test, and Fisher's exact test. The indoor environmental factors affecting sleep behavior were analyzed using logistic regression analysis. RESULTS: Children with AR (n=427) had a higher probability of snoring (8.7 % vs. 2.9 %; P < 0.001), mouth breathing (14.1 % vs. 5.2 %; P < 0.001), restless sleep (6.6 % vs. 4.1 %; P = 0.047), sleep talking (3.3 % vs. 1.1 %; P = 0.003), and hyperhidrosis (16.4 % vs. 8.5 %; P < 0.001) than those without AR (n=1046). Emulsion wall paint (odds ratio (OR) = 2.779; 95 % confidence interval (CI), 1.332-5.796; P = 0.006) and tobacco exposure in early infancy (OR = 2.065; 95 % CI 1.079-3.950; P = 0.029) were associated with hyperhidrosis. CONCLUSION: Children with AR are more likely to have abnormal sleep behaviors than those without, including snoring, mouth breathing, restless sleep, sleep talking, and hyperhidrosis. Emulsion paint wall and tobacco smoke exposure in early infancy had a twofold higher risk of hyperhidrosis during sleep.


Asunto(s)
Hiperhidrosis , Rinitis Alérgica , Trastornos de la Transición Sueño-Vigilia , Estudios de Casos y Controles , Niño , Emulsiones , Humanos , Respiración por la Boca , Factores de Riesgo , Sueño , Ronquido
2.
Anal Bioanal Chem ; 407(2): 447-53, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25433682

RESUMEN

A highly sensitive electrochemiluminescent (ECL) biosensor was designed for the detection of concanavalin A (ConA) based on glucose oxidase (GOx) as a recognition element by carbohydrate-lectin biospecific interaction, and poly(ethylenimine) (PEI) reduced graphene and hollow gold nanoparticles (HAuNPs) as supporting matrix and signal amplifier. The modification process and detection principle of the biosensor are briefly described as follows. First, PEI reduced graphene oxide with abundant amino groups was cast onto the surface of glassy carbon electrode to adsorb HAuNPs for improving the signal intensity in luminol/H2O2 ECL system. Next, GOx was further assembled onto the electrode by the interaction between Au and -NH2. In the presence of glucose in the detection solution, GOx catalyzed glucose to generate H2O2 in situ, which served as a co-reactant of luminol to enhance ECL signal of luminol. Based on the fact that ConA could result in a decrease in ECL signal when immobilized on the electrode, an ECL biosensor was prepared for the determination of ConA. The ECL signal intensity was linear with the logarithm of ConA concentration and the linear range was from 1.0 to 20 ng/mL with a low detection limit of 0.31 ng/mL (signal to noise ratio =3). This strategy led to a nearly 1000-fold improvement in detection limit for ConA assays compared with previously reported method, thus exhibiting a great potential application in sensitive bioassays of ConA.


Asunto(s)
Técnicas Biosensibles/métodos , Concanavalina A/análisis , Técnicas Electroquímicas/métodos , Nanopartículas/química , Animales , Técnicas Biosensibles/instrumentación , Bovinos , Concanavalina A/sangre , Técnicas Electroquímicas/instrumentación , Enzimas Inmovilizadas/química , Glucosa Oxidasa/química , Oro , Grafito/química , Humanos , Peróxido de Hidrógeno/química , Límite de Detección , Mediciones Luminiscentes/métodos , Luminol/química , Polietileneimina/química , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
3.
Soft Matter ; 10(18): 3301-10, 2014 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-24637918

RESUMEN

A new concept of gecko-inspired double-sided adhesives (DSAs) is presented. The DSAs, constructed by dual-angled (i.e. angled base and angled tip) micro-pillars on both sides of the backplane substrate, are fabricated by combinations of angled etching, mould replication, tip modification, and curing bonding. Two types of DSA, symmetric and antisymmetric (i.e. pillars are patterned symmetrically or antisymmetrically relative to the backplane), are fabricated and studied in comparison with the single-sided adhesive (SSA) counterparts through both non-conformal and conformal tests. Results indicate that the DSAs show controllable and bidirectional adhesion. Combination of the two pillar-layers can either amplify (for the antisymmetric DSA, providing a remarkable and durable adhesion capacity of 25.8 ± 2.8 N cm⁻² and a high anisotropy ratio of ∼8) or counteract (for the symmetric DSA, generating almost isotropic adhesion) the adhesion capacity and anisotropic level of one SSA (capacity of 16.2 ± 1.7 N cm⁻² and anisotropy ratio of ∼6). We demonstrate that these two DSAs can be utilized as a facile fastener for two individual objects and a small-scale delivery setup, respectively, complementing the functionality of the commonly studied SSA. As such, the double-sided patterning is believed to be a new branch in the further development of biomimetic dry adhesives.


Asunto(s)
Acrilatos/química , Adhesivos/química , Poliuretanos/química , Adhesividad , Animales , Biomimética , Lagartos
4.
Chem Biol Drug Des ; 104(1): e14580, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-39031936

RESUMEN

Demethylcantharidin (DEM) is a widely used antitumor drug; however, its poor tumor targeting and serious organotoxicity limit its application. The aim of this study was to develop a new drug delivery system for efficient delivery of DEM. Nanoemulsion based lipid nanoparticles containing demethylcantharidin (DNLNs) were prepared by loading nanoemulsions into lipid nanoparticles. The cells proliferation, apoptosis, cycle, and uptake were investigated by Cell counting kit-8 (CCK-8), flow cytometry, and in situ fluorescence assays, respectively. Then, we established the H22 tumor-bearing mouse model to evaluate the antitumor efficacy of DNLNs and further studied its organ toxicity and distribution. DNLNs significantly inhibited the proliferation and promoted apoptosis of H22 cells, and H22 cells could take up more DNLNs. Compared with DEM, DNLNs had certain tumor-targeting properties, and the tumor inhibition rate increased by 23.24%. Moreover, DNLNs can increase white blood cell count and reduce organ toxicity. This study paves the way for nanoemulsion-based lipid nanoparticle (NLNs)-efficient DEM delivery to treat liver cancer.


Asunto(s)
Antineoplásicos , Apoptosis , Emulsiones , Neoplasias Hepáticas , Nanopartículas , Animales , Ratones , Nanopartículas/química , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/patología , Línea Celular Tumoral , Emulsiones/química , Apoptosis/efectos de los fármacos , Antineoplásicos/química , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Lípidos/química , Humanos , Proliferación Celular/efectos de los fármacos , Compuestos Bicíclicos Heterocíclicos con Puentes/química , Compuestos Bicíclicos Heterocíclicos con Puentes/farmacología , Compuestos Bicíclicos Heterocíclicos con Puentes/uso terapéutico , Portadores de Fármacos/química , Sistemas de Liberación de Medicamentos , Liposomas
5.
Phys Chem Chem Phys ; 15(47): 20764-70, 2013 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-24196423

RESUMEN

Geckos' outstanding abilities to adhere to various surfaces are widely credited to the large actual contact areas of the fibrillar and hierarchical structures on their feet. These special features regulate the essential structural compliance for every attachment and thus provide robust yet reversible adhesions. Inspired by gecko's feet and our commonly used double-faced tape, we have successfully fabricated a gecko-inspired double-sided dry adhesive by using porous anodic alumina template assisted nano-wetting on a stiff polymer. It was determined that the obtained 2-sided structure showed largely decreased effective stiffness compared with its 1-sided counterpart, which favored better compliance and interfacial integrity. We also demonstrated that the repeatable double-sided adhesive improved the macroscopic normal and shear adhesion capacities over the widely-studied 1-side structure by ~50% and ~85%, respectively. By using the synthetic double-sided adhesive, the usage of traditional pressure-sensitive/chemical adhesives could be well avoided. Besides, the double-sided nanostructures showed great potential in finding new interesting properties and practical applications for the synthetic dry adhesives.


Asunto(s)
Adhesivos/química , Óxido de Aluminio/química , Queratinas/química , Nanofibras/química , Nanoporos , Polímeros/química , Propiedades de Superficie
6.
J Sep Sci ; 34(16-17): 2305-13, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21661109

RESUMEN

Monolithic silica capillary columns synthesized following a three-level design were evaluated for the electrochromatographic separation of acidic and neutral compounds. The influences of four factors in the sol-gel synthesis, i.e. the concentrations of tetramethylorthosilicate (TMOS) and PEG in the starting mixture, the gelation temperature and the silanization modifying time, on the electrochromatographic performance of the resulting C18-silica capillary monoliths were studied. The considered responses were retention factor, resolution, symmetry factor, column efficiency, electrokinetic porosity and the equivalent length of the monolith. The four factors were varied to change the pore structure and the surface coverage with octadecyl moieties, resulting in nine stationary phases. The retentive properties of the columns were initially characterized with alkylbenzenes. Next, the separation for acetylsalicylic acid (ASA) and its related compounds was optimized and used to evaluate the performance of the nine stationary phases considering six responses. A compromise between the different responses was found around higher concentrations of tetramethylorthosilicate and PEG with a lower gelation temperature and a modifying time of 2 h. Column efficiencies up to 96,000 plates/m and resolutions above 1.9 were obtained for the acetylsalicylic acid separation, with a sufficient EOF to yield rapid analysis, which showed improvements over the center-point stationary phase.


Asunto(s)
Electrocromatografía Capilar/instrumentación , Polímeros/química , Dióxido de Silicio/química , Concentración de Iones de Hidrógeno , Polímeros/síntesis química , Porosidad , Proyectos de Investigación , Temperatura
7.
Shanghai Kou Qiang Yi Xue ; 30(1): 85-88, 2021 Feb.
Artículo en Zh | MEDLINE | ID: mdl-33907786

RESUMEN

PURPOSE: To investigate the effects of different orthodontic treatments on gingival crevicular fluid chemokine CX3CL1, nuclear factor κB receptor activating factor ligand/osteoprotegerin(RANKL/OPG) levels in patients with malocclusion. METHODS: Ninety-six patients with malocclusion who were scheduled to undergo orthodontic treatment were randomly divided into four groups. All patients were treated with square wire appliance, and 0, 50, 150, 250 g of far-distal orthodontic force were given respectively. The levels of CX3CL1 and RANKL/OPG in gingival crevicular fluid were detected in four groups after 1, 2, 3, and 4 weeks of treatment. SPSS 25.0 software package was used for statistical analysis of the date. RESULTS: The levels of CX3CL1, RANKL and RANKL/OPG in the gingival crevicular fluid of the four groups were continuously increased after treatment for 1-3 weeks, and decreased after 4 weeks of treatment (P<0.05). The OPG in the gingival crevicular fluid was at a low level after 1-3 weeks of treatment. There was an increase after 4 weeks of treatment (P<0.05). The levels of CX3CL1, RANKL, OPG and RANKL/OPG in gingival crevicular fluid increased gradually in group A, B, C and D (P<0.05), and the differences between the groups were statistically significant (P<0.05). CONCLUSIONS: The levels of CX3CL1 and RANKL/OPG in gingival crevicular fluid are closely related to orthodontic force and treatment time, and can be used as an index to evaluate orthodontic treatment of alveolar bone remodeling.


Asunto(s)
Quimiocina CX3CL1 , Maloclusión , Remodelación Ósea , Líquido del Surco Gingival , Humanos , Osteoprotegerina , Ligando RANK , Esputo/química
8.
J Chromatogr A ; 1659: 462651, 2021 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-34749184

RESUMEN

A novel polyhedral oligomeric siloxane (POSS)-based zwitterionic monolithic capillary column was prepared via one-pot polymerization in ionic liquid porogen, using N,N-dimethyl-N-methacryloxyethyl-N-(3-sulfopropyl)ammonium betaine (DMMSA) and methacrylic ethyl trimethylammonium chloride (META) as binary functional monomers, and methacryl substituted POSS as cross-linker. The pore structure, permeability and homogeneity were well tuned by optimizing the polymerization conditions. The resultant monolith was characterized by scanning electron microscopy, nitrogen adsorption/desorption isotherm and Fourier transform infrared spectroscopy. The incorporation of zwitterionic ligand (DMMSA), quaternary amine group (META) and rigid POSS skeleton endows the hybrid organic-silica monolith with high hydrophilicity, electrostatic interaction and good mechanical stability, as well as a tunable electroosmotic flow over wide pH range. A close investigation of capillary electrochromatographic separations of different types of polar compounds such as bases, nucleosides and benzoic acids on such stationary phase exhibited a retention independent column efficiency up to 118,000 plates/m (thiourea), as well as a mixed-mode hydrophilic interaction chromatography (HILIC) retention mechanism including weak electrostatic interaction, hydrophobic interaction and anion exchange.


Asunto(s)
Electrocromatografía Capilar , Líquidos Iónicos , Interacciones Hidrofóbicas e Hidrofílicas , Polimerizacion , Siloxanos
9.
Electrophoresis ; 31(10): 1674-80, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20408131

RESUMEN

A neutral, nonpolar monolithic capillary column was evaluated as a hydrophobic stationary phase in pressurized CEC system for neutral, acidic and basic solutes. The monolith was prepared by in situ copolymerization of octadecyl methacrylate and ethylene dimethacrylate in a binary porogenic solvent consisting of cyclohexanol/1,4-butanediol. EOF in this hydrophobic monolithic column was poor; even the pH value of the mobile phase was high. Because of the absence of fixed charges, the monolithic capillary column was free of electrostatic interactions with charged solutes. Separations of neutral solutes were based on the hydrophobic mechanism with the pressure as the driving force. The acidic and basic solutes were separated under pressurized CEC mode with the pressure and electrophoretic mobility as the driving force. The separation selectivity of charged solutes were based on their differences in electrophoretic mobility and hydrophobic interaction with the stationary phase, and no obvious peak tailing for basic analytes was observed. Effects of the mobile phase compositions on the retention of acidic compounds were also investigated. Under optimized conditions, high plate counts reaching 82,000 plates/m for neutral compounds, 134,000 plates/m for acid compounds and 150,000 plates/m for basic compounds were readily obtained.


Asunto(s)
Electrocromatografía Capilar/métodos , Metacrilatos/química , Ácidos Polimetacrílicos/química , Acetonitrilos/química , Compuestos de Anilina/química , Ácidos Carboxílicos/química , Concentración de Iones de Hidrógeno , Microscopía Electrónica de Rastreo , Ácidos Polimetacrílicos/síntesis química
10.
J Sep Sci ; 33(14): 2123-30, 2010 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-20535749

RESUMEN

Molecularly imprinted polymer (MIP) monoliths with (S)-ornidazole ((S)-ONZ) as the template molecule have been designed and prepared by the simple thermal polymerization of methacrylic acid, 4-vinylpyridine, and ethylene dimethacrylate in the presence of a binary porogenic mixture of toluene and dodecanol. The influences of polymerization mixture composition on the chiral recognition of ONZ have been evaluated, and the imprint effect in the optimized MIP monolith has been clearly demonstrated. The new monolithic stationary phase with optimized porous property and good selectivity was used for the chiral separation of ONZ by pressurized CEC. The pressurized CEC conditions were also optimized to obtain the good chiral separation. The enantiomers were rapidly separated within 9 min on the MIP-based chiral stationary phase, whereas the chiral separation was not obtained on the nonimprinted polymer. Additionally, the proposed method has been successfully applied to the chiral separation of ONZ in tablet samples by injection of the crude sample. The cross-selectivity for similar antiparasitic drug was investigated. The results indicated that the chiral separation of secnidazole could also be obtained on the optimized MIP monolith within 14 min.


Asunto(s)
Amebicidas/análisis , Electrocromatografía Capilar , Impresión Molecular/métodos , Ornidazol/análisis , Polímeros/química , Antiprotozoarios/análisis , Tampones (Química) , Electrocromatografía Capilar/instrumentación , Electrocromatografía Capilar/métodos , Reactivos de Enlaces Cruzados , Concentración de Iones de Hidrógeno , Metronidazol/análogos & derivados , Metronidazol/análisis , Microscopía Electrónica de Rastreo , Estructura Molecular , Porosidad , Solventes/química , Estereoisomerismo
11.
J Chromatogr A ; 1623: 461175, 2020 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-32505279

RESUMEN

An ionic liquid hybrid zwitterionic polymer capillary microextraction (CME) column was prepared for the biomimetic enrichment of glycopeptides by one-step copolymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) and 1-butyl-3-vinylimidazolium bromide, in the presence of crosslinker trimethylolpropane trimethacrylate (TMA). The resultant monolith was characterized by scanning electron microscopy (SEM), fourier transform infrared (FT-IR) spectroscopy and pore size distribution measurement. Due to the incorporation of zwitterionic MPC owning a unique biomimic structure (i.e. hydrophilic cation/anion and hydrophobic long-alkyl chain), the monolithic column has large pore size and good biocompatibility, exhibiting high extraction efficiency, permeability and fast mass transfer to targets. Besides, the use of ionic liquids (ILs) as co-monomer in the polymerization endows the monolith with enhanced mechanical stability, uniformity and multiple interactions. The prepared column was successfully applied in CME coupled to capillary electrochromatography (CEC) for the efficient enrichment and separation of glycopeptide antibiotics in foodstuff. The method demonstrated a wide linear range (50.0-18000.0 µg L-1), low detection limits (5.0-10.0 µg L-1, S/N = 3) and satisfied recoveries (76.0-109.7%). This work shows the advantage of fine-tuning biomimetic monoliths in application-specific CME-CEC.


Asunto(s)
Antibacterianos/análisis , Electrocromatografía Capilar/métodos , Glicopéptidos/análisis , Líquidos Iónicos/química , Antibacterianos/aislamiento & purificación , Materiales Biomiméticos , Fraccionamiento Químico , Análisis de los Alimentos/métodos , Glicopéptidos/aislamiento & purificación , Interacciones Hidrofóbicas e Hidrofílicas , Imidazoles/química , Metacrilatos/química , Microscopía Electrónica de Rastreo , Fosforilcolina/análogos & derivados , Fosforilcolina/química , Polimerizacion , Polímeros/química , Espectroscopía Infrarroja por Transformada de Fourier , Compuestos de Vinilo/química
12.
J Chromatogr A ; 1556: 10-20, 2018 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-29729861

RESUMEN

A hydrophilic ionic liquids based polymer monolith microextraction (PMME) column (poly(ionic liquid-co-hydroxyethyl methacrylate-co-ethylene dimethacrylate); poly(IL-co-HEMA-co-EDMA)) was prepared for the first time in a capillary and utilized in PMME for the enrichment of glycopeptide antibiotics (GAs), followed by the online coupling analysis of capillary liquid chromatography with amperometric detection (cLC-AD). The prepared monolith exhibited large through pores and good storage stability, as well as a selective extraction machanism for GAs that was attributed to the hydrogen bonding, hydrophilic, electrostatic and π-π interactions between GAs and the imidazolium cations or hydroxyl groups on the surface of absorbent. Several experimental parameters, such as sample flow rate, composition of eluent and solvent desorption conditions, were examined to improve the extraction efficiency of PMME. Under the optimal conditions, the proposed PMME-cLC-AD method provides detection limits (S/N = 3) of 1.0-8.0 µg L-1 for three GAs, which are 1000-fold lower than those obtained by cLC-AD, with a wide linear range of 10.0-12000.0 µg L-1. It was successfully applied for the analysis of GAs residues in feed samples with good recoveries (80.3-119.1%) and satisfied intra-day/inter-day precision (<10%). Compared with LC-3Q-MS method, the proposed online approach has the merits of simple, low cost, smaller matrix interference and environmental friendly, which is demonstrated to be a feasible tool for residue analysis of peptide antibiotics in food safety application.


Asunto(s)
Antibacterianos/análisis , Cromatografía Líquida de Alta Presión/métodos , Electroquímica/métodos , Glicopéptidos/análisis , Interacciones Hidrofóbicas e Hidrofílicas , Líquidos Iónicos/química , Polímeros/química , Microextracción en Fase Sólida/métodos , Acetonitrilos/química , Metacrilatos/química , Polimerizacion , Porosidad , Reproducibilidad de los Resultados , Reología , Solventes , Espectroscopía Infrarroja por Transformada de Fourier , Factores de Tiempo
13.
J Chromatogr A ; 1570: 10-18, 2018 Oct 05.
Artículo en Inglés | MEDLINE | ID: mdl-30076008

RESUMEN

For solid phase microextraction (SPME), effective immobilization of sorbent on a stainless steel fiber surface is very essential. But, it still remains challenging because the chemical inertness of stainless steel fiber. In this work, chemical bonding method was introduced to fabricate a series of metal-organic frameworks (MOFs)-coated stainless steel fibers, and some representative MOFs (ZIF-90 (Zn), MOF-199 (Cu), MIL-101 (Cr), MOF-5 (Zn))-coated stainless steel fibers were successfully synthesized. Such strategy can noticeably increase the mechanical and chemical stability, and prolong the service lifetime due to it combine the advantages of stainless steel fiber and chemical bonding method. The stability of MOF-ZIF-90 (Zn)-coated stainless steel fibers which were preparated by different methods (chemical bonding method, adhesive method and deposition method) were studied, and results showed the chemical bonding method proved the best stability. Based on the ZIF-90 (Zn)-coated fiber, the SPME-GC-MS method was developed for detecting traces of polychlorinated biphenyls (PCBs) and satisfactory results were obtained. The linear ranges were 0.01-600 ng L-1 and the coefficient of determination was higher than 0.993. The limits of detection for the PCBs were 0.0013-0.053 ng L-1. The recoveries for the spiked PCBs in the Minjiang water, soil and vegetable oil samples were in the range of 85.9-105.8%. The extraction capacity of the ZIF-90 (Zn)-coated stainless steel fiber prepared by chemical bonding method did not show measurable change under different temperatures or organic solvents for up to 5 days.


Asunto(s)
Estructuras Metalorgánicas/química , Bifenilos Policlorados/aislamiento & purificación , Microextracción en Fase Sólida/métodos , Acero Inoxidable/química , Contaminantes Químicos del Agua/aislamiento & purificación , Bifenilos Policlorados/análisis , Contaminantes Químicos del Agua/análisis
14.
J Chromatogr A ; 1169(1-2): 220-7, 2007 Oct 26.
Artículo en Inglés | MEDLINE | ID: mdl-17875313

RESUMEN

In this report, the preparation of porous polymethacrylate-based monolithic columns by in situ copolymerization of octadecyl methacrylate (OMA), 3-sulfopropyl methacrylate (SPMA) and ethylene dimethacrylate (EDMA) in a binary porogenic solvent consisting of cyclohexanol/1,4-butanediol are proposed. These monoliths possess in their structures bonded octadecyl ligands and sulfonate groups and are evaluated in pressurized capillary electrochromatography (pCEC) system using small neutral and charged solutes. While the sulfonate groups are meant to generate the electroosmotic flow (EOF) necessary for transporting the mobile phase through the monolithic capillary; the octadecyl ligands are introduced to provide the nonpolar sites for chromatographic retention for neutral solutes. However, incorporating the sulfonate groups in the monoliths does not only support the EOF but also exhibit hydrophilic interaction as well as electrostatic interaction/repulsion with the monoliths in addition to electrophoretic migration with polar charged solutes (e.g., nucleotides). The monolithic stationary phases at different EOF velocities are easily prepared by altering the amount of SPMA in the polymerization solution as well as the composition of the porogenic solvent. Optimum EOF velocity, the highest efficiency and adequate chromatographic retention are obtained when 0.6% SPMA is added to the reaction mixture. Under these conditions, rapid separation and high plate counts reaching greater than 170,000 plates/m are readily obtained.


Asunto(s)
Cromatografía Capilar Electrocinética Micelar/instrumentación , Cromatografía Capilar Electrocinética Micelar/métodos , Nucleótidos/análisis , Polimetil Metacrilato/química , Dióxido de Silicio/química , Soluciones/análisis , Ácidos Sulfónicos/química , Tampones (Química) , Electroósmosis/métodos , Concentración de Iones de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Ligandos , Nucleótidos/química , Porosidad , Presión , Soluciones/química , Solventes/química
15.
J Chromatogr A ; 1161(1-2): 51-5, 2007 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-17307188

RESUMEN

The mutant of human basic fibroblast growth factor (hbFGF), hbFGF(Ser25,87,92), which was constructed by replacing the cysteine residues at the positions of the 25th, the 87th and the 92nd with serine residues, was coupled to polyethylene glycol (PEG) with a molecular size of 20 kDa (20K) (PEG(20K)) to obtain hbFGF derivative, PEG(20K)-hbFGF(Ser25,87,92). The optimal modified reaction was conducted at 12 degrees C for 12h with the molar ratio of PEG(20K) to hbFGF(Ser25,87,92) of 30:1. The result of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed that the modification rate was up to 60%. The PEGylated product retained binding affinity to heparin and could be purified by heparin affinity chromatography. Compared to hbFGF mutant, purified PEG(20K)-hbFGF(Ser25,87,92) retained about 34% of mitogenic activity. Heat-stability assay indicated that the modified product was more stable than the native protein at the temperature of 37 degrees C.


Asunto(s)
Factor 2 de Crecimiento de Fibroblastos/aislamiento & purificación , Polietilenglicoles/química , Electroforesis en Gel de Poliacrilamida , Factor 2 de Crecimiento de Fibroblastos/genética , Factor 2 de Crecimiento de Fibroblastos/farmacología , Humanos , Mitosis/efectos de los fármacos , Mutagénesis Sitio-Dirigida , Proteínas Recombinantes/genética , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/farmacología
16.
Toxicol Lett ; 170(2): 146-56, 2007 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-17416472

RESUMEN

Molecular modification with polyethylene glycol (PEGylation) is an effective approach to improve protein biostability and decrease protein immunogenic activity. To create a PEGylated recombinant human acid fibroblast growth factor (rhaFGF) and improve its bio-stability, we have produced a rhaFGF mutant (rhaFGF(ser98,132)) by replacing the 98th and the 132nd cysteine residues with serine residues. The rhaFGF(ser98,132) that retains the bioactivity of rhaFGF was then site-specifically conjugated with PEG-maleimide at the 31st cysteine residue. PEGylated rhaFGF(ser98,132) has less effect than the native rhaFGF(ser98,132) on stimulating 3T3 cell proliferation in vitro; however, its biostability at a prolonged incubation under various temperatures and resistance to trypsinization were significantly enhanced, and half-life time in vivo was elongated while its immunogenicity was significantly decreased. The physiological function of PEGylated rhaFGF(ser98,132) was evaluated in a rat model of retinal ischemia/reperfusion injury, showing that in vivo supplementation of PEGylated rhaFGF(ser98,132) provided a significantly better protection than the native rhaFGF(ser98,132) against ischemia/reperfusion-induced retinal morphological changes and lipid peroxidation. The protection is probably mediated by antioxidant protective mechanisms.


Asunto(s)
Factores de Crecimiento de Fibroblastos/farmacología , Polietilenglicoles/farmacología , Daño por Reperfusión/prevención & control , Degeneración Retiniana/prevención & control , Animales , Células 3T3 BALB/efectos de los fármacos , Células 3T3 BALB/metabolismo , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Estabilidad de Medicamentos , Femenino , Factores de Crecimiento de Fibroblastos/metabolismo , Humanos , Presión Intraocular/efectos de los fármacos , Peroxidación de Lípido/efectos de los fármacos , Ratones , Ratones Endogámicos BALB C , Mutagénesis Sitio-Dirigida , Polietilenglicoles/metabolismo , Ratas , Ratas Sprague-Dawley , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacología , Daño por Reperfusión/metabolismo , Daño por Reperfusión/patología , Retina/efectos de los fármacos , Retina/metabolismo , Retina/patología , Degeneración Retiniana/metabolismo , Degeneración Retiniana/patología
17.
J Pharm Biomed Anal ; 43(1): 352-7, 2007 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-16875795

RESUMEN

A pressurized capillary electrochromatography (pCEC) with monolithic column has been developed for the rapid separation and determination of five structurally related anthraquinones in Rhubarb. The possibility of rapid separation resulted from the unique pore structure with high permeability and favorable mass transfer characteristics of the monolithic stationary phase. The effect factors such as organic modifier, acidity and concentration of running buffer, separation voltage were investigated to acquire the optimum condition. In the 220 nm wavelengths, the five anthraquinones could be baseline-separated rapidly within 5 min with the separation voltage of -20 kV in 10 mmol/L phosphate buffer (pH 6.2) containing 65% acetonitrile. The calibration graphs of rhein, aloe-emodin, emodin chrysophanol and physcion were linear by plotting the peak area against the analytes concentration over the range of 0.2-65, 0.1-30, 0.1-55, 0.5-30 and 0.5-55 microg/mL, respectively. The detection limits of five anthraquinones were ranged from 0.06 to 0.2 microg/mL and the recoveries of Rhubarb samples were about 81.3-86.4% (R.S.D.< or = 5.2%). This proposed method was successfully applied to determination of the five analytes in Rhubarb with satisfactory results.


Asunto(s)
Antraquinonas/química , Rheum/química , Antraquinonas/aislamiento & purificación , Tampones (Química) , Electroforesis Capilar , Concentración de Iones de Hidrógeno , Modelos Lineales , Metacrilatos/análisis , Ácidos Polimetacrílicos/química , Reproducibilidad de los Resultados
18.
Bioresour Technol ; 183: 10-7, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25710678

RESUMEN

The continual growth in commercial aviation fuels and more strict environmental legislations have led to immense interest in developing green aviation fuels from biomass. This paper demonstrated a controllable transformation of lignin into jet and diesel fuel range hydrocarbons, involving directional production of C8-C15 aromatics by the catalytic depolymerization of lignin into C6-C8 low carbon aromatic monomers coupled with the alkylation of aromatics, and the directional production of C8-C15 cycloparaffins by the hydrogenation of aromatics. The key step, the production of the desired C8-C15 aromatics with the selectivity up to 94.3%, was achieved by the low temperature alkylation reactions of the lignin-derived monomers using ionic liquid. The synthetic biofuels basically met the main technical requirements of conventional jet fuels. The transformation potentially provides a useful way for the development of cycloparaffinic and aromatic components in jet fuels using renewable lignocellulose biomass.


Asunto(s)
Biocombustibles , Biomasa , Cicloparafinas/química , Gasolina , Lignina/química , Alcanos/química , Alquilación , Catálisis , Hidrogenación , Líquidos Iónicos/química , Polimerizacion , Reciclaje , Temperatura
19.
PLoS One ; 6(6): e20669, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21673953

RESUMEN

As one of fibroblast growth factor (FGF) family members, FGF21 has been extensively investigated for its potential as a drug candidate to combat metabolic diseases. In the present study, recombinant human FGF21 (rhFGF21) was modified with polyethylene glycol (PEGylation) in order to increase its in vivo biostabilities and therapeutic potency. At N-terminal residue rhFGF21 was site-selectively PEGylated with mPEG20 kDa-butyraldehyde. The PEGylated rhFGF21 was purified to near homogeneity by Q Sepharose anion-exchange chromatography. The general structural and biochemical features as well as anti-diabetic effects of PEGylated rhFGF21 in a type 2 diabetic rat model were evaluated. By N-terminal sequencing and MALDI-TOF mass spectrometry, we confirmed that PEG molecule was conjugated only to the N-terminus of rhFGF21. The mono-PEGylated rhFGF21 retained the secondary structure, consistent with the native rhFGF21, but its biostabilities, including the resistance to physiological temperature and trypsinization, were significantly enhanced. The in vivo immunogenicity of PEGylated rhFGF21 was significantly decreased, and in vivo half-life time was significantly elongated. Compared to the native form, the PEGylated rhFGF21 had a similar capacity of stimulating glucose uptake in 3T3-L1 cells in vitro, but afforded a significantly long effect on reducing blood glucose and triglyceride levels in the type 2 diabetic animals. These results suggest that the PEGylated rhFGF21 is a better and more effective anti-diabetic drug candidate than the native rhFGF21 currently available. Therefore, the PEGylated rhFGF21 may be potentially applied in clinics to improve the metabolic syndrome for type 2 diabetic patients.


Asunto(s)
Factores de Crecimiento de Fibroblastos/química , Factores de Crecimiento de Fibroblastos/farmacología , Hipoglucemiantes/química , Hipoglucemiantes/farmacología , Polietilenglicoles/química , Proteínas Recombinantes/química , Proteínas Recombinantes/farmacología , Células 3T3-L1 , Aldehídos/química , Animales , Glucemia/metabolismo , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Estabilidad de Medicamentos , Femenino , Factores de Crecimiento de Fibroblastos/farmacocinética , Factores de Crecimiento de Fibroblastos/uso terapéutico , Humanos , Hipoglucemiantes/farmacocinética , Hipoglucemiantes/uso terapéutico , Metabolismo de los Lípidos/efectos de los fármacos , Masculino , Ratones , Ratas , Proteínas Recombinantes/farmacocinética , Proteínas Recombinantes/uso terapéutico , Relación Estructura-Actividad
20.
Biosens Bioelectron ; 25(6): 1414-9, 2010 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-19945840

RESUMEN

A new biocompatible ECL biosensor based on enzyme/titanate nanotubes/chitosan composite film was developed for the determination of analytes in biological samples. In the fabrication of the new ECL biosensor, biocompatible titanate nanotubes (TNTs) and a model enzyme, i.e., choline oxidase (ChOX), were immobilized on a chitosan modified glassy carbon electrode (GCE) via electrostatic adsorption and covalent interaction, respectively. By this ECL biosensor, choline was enzymatically oxidized to hydrogen peroxide and detected by a sensitive luminol ECL system. The use of TNTs not only provided a biocompatible microenvironment for the immobilized enzyme, which resulted in an excellent stability and long lifetime of the ECL biosensor, but also exhibited great enhancement towards luminol ECL and thus led to a significant improvement in sensitivity of ECL biosensor. Satisfactory results were obtained when employing this biosensor in assaying the total choline in milk samples. The work would provide a common platform to develop various sensitive, selective and biocompatible ECL biosensors based on using enzyme/TNTs/CHIT composite films.


Asunto(s)
Oxidorreductasas de Alcohol/química , Técnicas Biosensibles/instrumentación , Quitosano/química , Colina/análisis , Conductometría/instrumentación , Mediciones Luminiscentes/instrumentación , Titanio/química , Materiales Biocompatibles/química , Colina/química , Electrodos , Enzimas Inmovilizadas/química , Diseño de Equipo , Análisis de Falla de Equipo , Nanotubos/química , Nanotubos/ultraestructura , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
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