Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 59
Filtrar
Más filtros

Bases de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Phys Chem Chem Phys ; 26(5): 4759-4765, 2024 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-38252531

RESUMEN

The design, synthesis and evaluation of a subphthalocyanine-flipper (SubPc-Flipper) amphiphilic dyad is reported. This dyad combines two fluorophores that function in the visible region (420-800 nm) for the simultaneous sensing of both ordered and disordered lipidic membranes. The flipper probes part of the dyad possesses mechanosensitivity, long fluorescence lifetimes (τ = 3.5-5 ns) and selective staining of ordered membranes. On the other hand, subphthalocyanines (SubPc) are short-lifetime (τ = 1-2.5 ns) fluorophores that are insensitive to membrane tension. As a result of a Förster Resonance Energy Transfer (FRET) process, the dyad not only retains the mechanosensitivity of flippers but also demonstrates high selectivity and emission in different kinds of lipidic membranes. The dyad exhibits high emission and sensitivity to membrane tension (Δτ = 3.5 ns) when tested in giant unilamellar vesicles (GUVs) with different membrane orders. Overall, the results of this study represent a significant advancement in the applications of flippers and dyads in mechanobiology.

2.
Angew Chem Int Ed Engl ; : e202406204, 2024 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-38758302

RESUMEN

Fluorescent flippers have been introduced as small-molecule probes to image membrane tension in living systems. This study describes the design, synthesis, spectroscopic and imaging properties of flippers that are elongated by one and two alkynes inserted between the push and the pull dithienothiophene domains. The resulting mechanophores combine characteristics of flippers, reporting on physical compression in the ground state, and molecular rotors, reporting on torsional motion in the excited state, to take their photophysics to new level of sophistication. Intensity ratios in broadened excitation bands from differently twisted conformers of core-alkynylated flippers thus report on mechanical compression. Lifetime boosts from ultrafast excited-state planarization and lifetime drops from competitive intersystem crossing into triplet states report on viscosity. In standard lipid bilayer membranes, core-alkynylated flippers are too long for one leaflet and tilt or extend into disordered interleaflet space, which preserves rotor-like torsional disorder and thus weak, blue-shifted fluorescence. Flipper-like planarization occurs only in highly ordered membranes of matching leaflet thickness, where they light up and selectively report on these thick membranes with red-shifted, sharpened excitation maxima, high intensity and long lifetime.

3.
Development ; 147(19)2020 10 05.
Artículo en Inglés | MEDLINE | ID: mdl-32907847

RESUMEN

Pattern formation is influenced by transcriptional regulation as well as by morphogenetic mechanisms that shape organ primordia, although factors that link these processes remain under-appreciated. Here we show that, apart from their established transcriptional roles in pattern formation, IRX3/5 help to shape the limb bud primordium by promoting the separation and intercalation of dividing mesodermal cells. Surprisingly, IRX3/5 are required for appropriate cell cycle progression and chromatid segregation during mitosis, possibly in a nontranscriptional manner. IRX3/5 associate with, promote the abundance of, and share overlapping functions with co-regulators of cell division such as the cohesin subunits SMC1, SMC3, NIPBL and CUX1. The findings imply that IRX3/5 coordinate early limb bud morphogenesis with skeletal pattern formation.


Asunto(s)
Cromátides/metabolismo , Proteínas de Homeodominio/metabolismo , Esbozos de los Miembros/embriología , Esbozos de los Miembros/metabolismo , Factores de Transcripción/metabolismo , Animales , Western Blotting , Segregación Cromosómica/genética , Segregación Cromosómica/fisiología , Femenino , Técnica del Anticuerpo Fluorescente , Células HEK293 , Proteínas de Homeodominio/genética , Humanos , Inmunoprecipitación , Espectrometría de Masas , Ratones , Mitosis/genética , Mitosis/fisiología , Embarazo , RNA-Seq , Reacción en Cadena en Tiempo Real de la Polimerasa , Factores de Transcripción/genética
4.
Appl Opt ; 62(17): 4524-4529, 2023 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-37707146

RESUMEN

In this paper, we build a Young's double-slit experimental platform with adjustable multiparameters by inserting a single slit in a Sagnac interferometer. Our experiment proves that this platform can easily control the parameters related to double slits. In addition, a new, to the best of our knowledge, type of double-slit experiment is performed on the platform. Our approach provides a detailed conceptual and experimental analysis for wave-particle duality and will be useful for research on quantum optics.

5.
Angew Chem Int Ed Engl ; 62(20): e202217868, 2023 05 08.
Artículo en Inglés | MEDLINE | ID: mdl-36734976

RESUMEN

Flipper probes have been introduced as small molecule fluorophores to image physical forces, that is, membrane tension in living systems. Their emergence over one decade is described, from evolution in design and synthesis to spectroscopic properties. Responsiveness to physical compression in equilibrium at the ground state is identified as the ideal origin of mechanosensitivity to image membrane tension in living cells. A rich collection of flippers is described to deliver and release in any subcellular membrane of interest in a leaflet-specific manner. Chalcogen-bonding cascade switching and dynamic covalent flippers are developed for super-resolution imaging and dual-sensing of membrane compression and hydration. Availability and broad use in the community validate flipper probes as a fine example of the power of translational supramolecular chemistry, moving from fundamental principles to success on the market.


Asunto(s)
Diagnóstico por Imagen , Colorantes Fluorescentes , Membrana Celular/química , Colorantes Fluorescentes/química
6.
Zhongguo Dang Dai Er Ke Za Zhi ; 25(11): 1124-1130, 2023 Nov 15.
Artículo en Zh | MEDLINE | ID: mdl-37990456

RESUMEN

OBJECTIVES: To investigate the clinical phenotypes, genetic characteristics, and pathological features of children with disorders of sex development (DSD). METHODS: A retrospective analysis was conducted on epidemiological, clinical phenotype, chromosomal karyotype, gonadal pathology, and genotype data of 165 hospitalized children with DSD at Children's Hospital of Hebei Province and Tangshan Maternal and Child Health Hospital from August 2008 to December 2022. RESULTS: Among the 165 children with DSD, common presenting symptoms were short stature (62/165, 37.6%), clitoromegaly (33/165, 20.0%), cryptorchidism (28/165, 17.0%), hypospadias (24/165, 14.5%), and skin pigmentation abnormalities/exteriorized pigmented labia majora (19/165, 11.5%). Chromosomal karyotype analysis was performed on 127 cases, revealing 36 cases (28.3%) of 46,XX DSD, 34 cases (26.8%) of 46,XY DSD, and 57 cases (44.9%) of sex chromosome abnormalities. Among the sex chromosome abnormal karyotypes, the 45,X karyotype (11/57, 19%) and 45,X/other karyotype mosaicism (36/57, 63%) were more common. Sixteen children underwent histopathological biopsy of gonadal tissues, resulting in retrieval of 25 gonadal tissues. The gonadal tissue biopsies revealed 3 cases of testes, 3 cases of dysplastic testes, 6 cases of ovaries, 11 cases of ovotestes, and 1 case each of streak gonad and agenesis of gonads. Genetic testing identified pathogenic/likely pathogenic variants in 23 cases (23/36, 64%), including 12 cases of 21-hydroxylase deficiency congenital adrenal hyperplasia caused by CYP21A2 pathogenic variants. CONCLUSIONS: Short stature, clitoromegaly, cryptorchidism, hypospadias, and skin pigmentation abnormalities are common phenotypes in children with DSD. 45,X/other karyotype mosaicism and CYP21A2 compound heterozygous variants are major etiological factors in children with DSD. The most commonly observed gonadal histopathology in children with DSD includes ovotestes, ovaries, and testes/dysgenetic testes.


Asunto(s)
Hiperplasia Suprarrenal Congénita , Criptorquidismo , Trastornos del Desarrollo Sexual , Hipospadias , Masculino , Humanos , Niño , Trastornos del Desarrollo Sexual/genética , Trastornos del Desarrollo Sexual/diagnóstico , Trastornos del Desarrollo Sexual/patología , Hipospadias/genética , Hipospadias/complicaciones , Criptorquidismo/complicaciones , Estudios Retrospectivos , Esteroide 21-Hidroxilasa
7.
Zhongguo Zhong Yao Za Zhi ; 47(14): 3898-3907, 2022 Jul.
Artículo en Zh | MEDLINE | ID: mdl-35850848

RESUMEN

This study observed the pharmacological effects of Feilike Mixture(FLKM) in stopping cough, eliminating phlegm, and relieving asthma through animal experiments, and explored its mechanism using network pharmacology. The antitussive effect was detected by citric acid-induced guinea pig cough model, the expectorant effect by mouse phenol red excretion experiment and lipopolysaccharide-induced mucus hypersecretion rat model, and the antiasthmatic effect by histamine phosphate-induced guinea pig asthma model. The chemical components of FLKM were collected by TCMSP, TCMID, TCMIP, and BATMAN-TCM databases and literature search, and the potential active components were screened through ADMETlab 2.0. The targets of FLKM were obtained by STITCH, SwissTargetPrediction, and TCMSP, and the symptom targets of cough, phlegm, and asthma were acquired through SymMap database. After taking the intersection of FLKM targets and symptom targets, this study used the OECloud tool to perform Gene Ontology(GO) and Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment analysis. RESULTS:: demonstrated that FLKM 0.43-1.74 g·kg~(-1) reduced the number of coughs in guinea pigs within 3 min(P<0.05, P<0.01), and FLKM 6-12 g·kg~(-1) increased the tracheal phenol red excretion in mice(P<0.01). Moreover, FLKM 2-8 g·kg~(-1) inhibited the number of goblet cells(P<0.05, P<0.01), and FLKM 7-11.2 g·kg~(-1) prolonged the incubation period of asthma(P<0.05). A total of 115 potential active components and 910 targets of FLKM were obtained through network pharmacological analysis. FLKM had 27, 12, and 7 targets for stopping cough, eliminating phlegm, and relieving asthma, respectively. The GO and KEGG enrichment analysis found that there were commonalities and characteristics, among which cytokine-cytokine receptor interaction and infectious disease-related signaling pathway were shared. FLKM has a good effect of stopping cough, eliminating phlegm, and relieving asthma through animal experiments and network pharmacology.


Asunto(s)
Experimentación Animal , Asma , Medicamentos Herbarios Chinos , Animales , Asma/inducido químicamente , Asma/tratamiento farmacológico , Tos/tratamiento farmacológico , Medicamentos Herbarios Chinos/farmacología , Cobayas , Ratones , Moco , Farmacología en Red , Fenolsulfonftaleína , Ratas
8.
Anal Chem ; 93(8): 3922-3928, 2021 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-33586972

RESUMEN

Clarifying the signaling pathway associated with nitric oxide (NO) and glutathione (GSH) in cardiovascular disease therapy is important for understanding its physiological and pathological processes but is challenging due to the lack of efficient analytical techniques. Herein, we report a BODIPY-based fluorescent probe for recognition of NO and GSH in sequence with high sensitivity and selectivity. The probe exhibits turn-on fluorescence triggered by NO, followed by red-shifted emission in the presence of GSH. The sequentially activated mechanism allows the visualization of NO-induced GSH upregulation in drug-treated endothelial cells and zebrafish for the first time, revealing a signal pathway during the therapy. We hope that it can be used as a convenient and efficient tool for the study of the interplay between NO and GSH and for the screening of effective drugs for cardiovascular disease therapy.


Asunto(s)
Enfermedades Cardiovasculares , Colorantes Fluorescentes , Animales , Enfermedades Cardiovasculares/tratamiento farmacológico , Células Endoteliales , Glutatión , Células HeLa , Humanos , Óxido Nítrico , Transducción de Señal , Pez Cebra
9.
Biochem Biophys Res Commun ; 568: 48-54, 2021 09 03.
Artículo en Inglés | MEDLINE | ID: mdl-34182213

RESUMEN

The F115C mutation in the MATR3 gene has been linked to amyotrophic lateral sclerosis (ALS). To determine the pathogenicity of the F115C mutation and the mechanism by which this mutation causes ALS, we generated mice that harbor the F115C mutation in the endogenous murine Matr3 locus. Heterozygous or homozygous MATR3 F115C knock-in mice were viable and did not exhibit motor deficits up to 2 years of age. The mutant mice showed no significant differences in the number of Purkinje cells or motor neurons compared to wild-type littermates. Neuropathological examination revealed an absence of MATR3 and TDP-43 pathology in Purkinje cells and motor neurons in the mutant mice. Together, our results suggest that the F115C mutation in MATR3 may not confer pathogenicity.


Asunto(s)
Esclerosis Amiotrófica Lateral/genética , Neuronas Motoras/patología , Proteínas Asociadas a Matriz Nuclear/genética , Proteínas de Unión al ARN/genética , Esclerosis Amiotrófica Lateral/patología , Animales , Técnicas de Sustitución del Gen , Ratones , Trastornos Motores/genética , Trastornos Motores/patología , Neuronas Motoras/metabolismo , Músculos/metabolismo , Músculos/patología , Mutación Puntual
10.
Clin Exp Hypertens ; 43(8): 788-792, 2021 Nov 17.
Artículo en Inglés | MEDLINE | ID: mdl-34423691

RESUMEN

Objective This study aimed to analyze the influence of SLCO1B1 and APOE gene polymorphisms on coronary heart disease in Mongolian population who living in Ordos area. Methods From January 2019 to June 2020, 200 Mongolian patients with coronary heart disease admitted to our hospital and other banner hospitals were selected as the case group. At the same time, 150 randomly selected healthy Mongolian people from medical examination centers comprised the control group. The polymorphisms of SLCO1B1 (388A>G, 521 T > C) and ApoE (388 T > C, 526 C > t) were detected by real-time polymerase chain reaction. Combined with environmental data, the effect of gene polymorphism on coronary heart disease was explored. Results Both SLCO1B1 and ApoE polymorphisms satisfied Hardy-Weinberg equilibrium. The SLCO1B1 genotype *1a/*1b showed the highest frequency in the case group, accounting for 35.0%, while The SLCO1B1 genotype *1b/*1b showed the highest frequency in the control group, accounting for 32.0%. Allele *1b was the most commonly seen allele in both the case group and control group (57.8% and 53.7%, respectively). Meanwhile, The difference in the distribution of SLCO1B1 *1a/*15 genotype between the two groups was statistically significant (P < .05). Conclusion The results showed that the SLCO1B *1a/*15 genotype, ApoE ε3 /ε3 genotype, and ε3 allele reduced the risk of coronary disease in the Mongolian population, making them protective genes against this disease, while the ApoE ε4 allele increased the risk of coronary disease, making it a coronary disease risk factor.


Asunto(s)
Apolipoproteínas E/genética , Enfermedad Coronaria , Hipertensión , Enfermedad Coronaria/epidemiología , Enfermedad Coronaria/genética , Genotipo , Humanos , Transportador 1 de Anión Orgánico Específico del Hígado/genética , Polimorfismo Genético
11.
Anal Chem ; 91(7): 4301-4306, 2019 04 02.
Artículo en Inglés | MEDLINE | ID: mdl-30829471

RESUMEN

Nitric oxide (NO) and glutathione (GSH) have interplaying roles in oxidant-antioxidant balance. In this work, we developed the first example of a single fluorescent probe that displayed a turn-on fluorescence response toward NO and GSH from dual emission channels. The probe was synthesized by introducing 4-amino-3-(methylamino)-phenol to a BODIPY scaffold. Specifically, the NO-mediated transformation of diamine into a triazole triggered the fluorescence in the green channel, and the GSH-induced SNAr substitution reaction led to the red-shifted emission in the red channel. The probe was successfully applied to detect the exogenous and endogenous NO and GSH in macrophage cells. More importantly, the probe revealed that NO induced by interferon-γ (IFN-γ), lipopolysaccharide (LPS), and l-arginine (l-Arg) could also elicit the augmentation of intracellular GSH. We anticipate the probe would hold great potential for investigating the redox balance in biological processes.


Asunto(s)
Compuestos de Boro/química , Colorantes Fluorescentes/química , Glutatión/análisis , Óxido Nítrico/análisis , Fenilendiaminas/química , Animales , Arginina/farmacología , Compuestos de Boro/toxicidad , Teoría Funcional de la Densidad , Colorantes Fluorescentes/toxicidad , Glutatión/metabolismo , Interferón gamma/farmacología , Límite de Detección , Lipopolisacáridos/farmacología , Ratones , Microscopía Confocal/métodos , Microscopía Fluorescente/métodos , Modelos Químicos , Óxido Nítrico/metabolismo , Fenilendiaminas/toxicidad , Células RAW 264.7
12.
Molecules ; 24(12)2019 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-31208101

RESUMEN

A chemical investigation of the fibrous roots of Anemarrhena asphodeloides Bge. led to the isolation of four benzophenones, including one new compound (1) and three known ones (2-4). Comprehensive 1D, 2D NMR and HRESIMS data established the structures of the isolated compounds. The absolute configurations were determined by comparison of the calculated optical rotation (OR) with experimental data. All the isolates were evaluated for their cytotoxicities on hepatocellular carcinoma cell lines (HepG2 and Hep3B). Compound 1 showed strong cytotoxicity against HepG2 and Hep3B cells, with IC50 values at 153.1 and 180.6 nM. Through MTT assay, flow cytometry and Western blot analysis, compound 1 demonstrated the ability to stimulate apoptosis via the NF-κB signaling pathway in HepG2 cells. These benzophenones are potential lead compounds for the development of better treatments for hepatocellular carcinoma.


Asunto(s)
Anemarrhena/química , Antineoplásicos Fitogénicos/farmacología , Benzofenonas/farmacología , Extractos Vegetales/farmacología , Antineoplásicos Fitogénicos/química , Apoptosis/efectos de los fármacos , Benzofenonas/química , Supervivencia Celular/efectos de los fármacos , Células Hep G2 , Humanos , Espectroscopía de Resonancia Magnética , Estructura Molecular , FN-kappa B/metabolismo , Extractos Vegetales/química , Raíces de Plantas/química , Transducción de Señal/efectos de los fármacos , Relación Estructura-Actividad
13.
Soft Matter ; 14(32): 6696-6707, 2018 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-30062357

RESUMEN

Several additives, including inorganic (NaCl) and organic salts (derivatives of benzoate), were added into aqueous solutions of a gemini cationic surfactant, 2-hydroxypropyl-1,3-bis (myristyldimethylammonium chloride) (abbreviated as 14-3(OH)-14(2Cl)). The mixed systems were investigated using rheological measurement, cryo-TEM and 1H NMR analysis. The results showed that addition of salts induced rich aggregate morphologies in the 14-3(OH)-14(2Cl)/salt systems. The influence of an inorganic salt on the viscoelasticity of 14-3(OH)-14(2Cl) solutions is much weaker than that of organic salts. Furthermore, the ability of three organic salts in enhancing the viscoelasticity of 14-3(OH)-14(2Cl) solutions is in the order sodium m-hydroxybenzoate > sodium o-hydroxybenzoate > sodium p-hydroxybenzoate. The different roles of these organic salt isomers arise from the different types of hydrogen bonding formed between 14-3(OH)-14(2Cl) and the organic counter ions.

14.
Microb Cell Fact ; 17(1): 1, 2018 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-29306327

RESUMEN

BACKGROUND: Mushroom showed pellet, clump and/or filamentous mycelial morphologies during submerged fermentation. Addition of microparticles including Talc (magnesium silicate), aluminum oxide and titanium oxide could control mycelial morphologies to improve mycelia growth and secondary metabolites production. Here, effect of microparticle Talc (45 µm) addition on the mycelial morphology, fermentation performance, monosaccharide compositions of polysaccharides and enzymes activities associated with polysaccharide synthesis in G. frondosa was well investigated to find a clue of the relationship between polysaccharide biosynthesis and morphological changes. RESULTS: Addition of Talc decreased the diameter of the pellets and increased the percentage of S-fraction mycelia. Talc gave the maximum mycelial biomass of 19.25 g/L and exo-polysaccharide of 3.12 g/L at 6.0 g/L of Talc, and mycelial polysaccharide of 0.24 g/g at 3.0 g/L of Talc. Talc altered the monosaccharide compositions/percentages in G. frondosa mycelial polysaccharide with highest mannose percentage of 62.76 % and lowest glucose percentage of 15.22 % followed with the corresponding changes of polysaccharide-synthesis associated enzymes including lowest UDP-glucose pyrophosphorylase (UGP) activity of 91.18 mU/mg and highest UDP-glucose dehydrogenase (UGDG) and GDP-mannose pyrophosphorylase (GMPPB) activities of 81.45 mU/mg and 93.15 mU/mg. CONCLUSION: Our findings revealed that the presence of Talc significantly changed the polysaccharide production and sugar compositions/percentages in mycelial and exo-polysaccharides by affecting mycelial morphology and polysaccharide-biosynthesis related enzymes activities of G. frondosa.


Asunto(s)
Grifola/metabolismo , Micelio/efectos de los fármacos , Polisacáridos/biosíntesis , Talco/farmacología , Óxido de Aluminio/farmacología , Biomasa , Medios de Cultivo , Fermentación , Grifola/efectos de los fármacos , Silicatos de Magnesio/farmacología , Microesferas , Micelio/química , Micelio/crecimiento & desarrollo , Micelio/metabolismo , Polisacáridos/análisis , Polisacáridos/metabolismo , Talco/química , Titanio/farmacología
15.
Zhongguo Zhong Yao Za Zhi ; 42(14): 2784-2788, 2017 Jul.
Artículo en Zh | MEDLINE | ID: mdl-29098838

RESUMEN

A solvent diffusion method was used to prepare pegylated asiatic acid (AA) loaded nanostructured lipid carriers (p-AA-NLC), and the ligated intestinal circulation model was established to observe the absorption and distribution in small intestine. The concentration of AA in bile after oral administration of p-AA-NLC was detected by HPLC in healthy SD rats to indirectly evaluate the oral absorption promoting effect of PEG-modified namoparticles. The results showed that the penetration of p-AA-NLC was enhanced significantly and the transport capacity was increased greatly in small intestinal after PEG modification. As compared with the normal nanoparticles (AA-NLC), the Cmax of the drug excretion was increased by 76%, the time to reach the peak (tmax ) was decreased and the elimination half-life t1/2 was doubled in the rats after oral administration of p-AA-NLC, and the AUC0→t was 1.5 times of the AA-NLC group, indicating that the oral bioavailability of AA-NLC was significantly improved by hydrophilic modification of PEG.


Asunto(s)
Portadores de Fármacos , Nanopartículas , Triterpenos Pentacíclicos/farmacocinética , Polietilenglicoles , Administración Oral , Animales , Semivida , Absorción Intestinal , Lípidos , Tamaño de la Partícula , Triterpenos Pentacíclicos/administración & dosificación , Ratas , Ratas Sprague-Dawley
16.
Zhongguo Dang Dai Er Ke Za Zhi ; 19(9): 1027-1033, 2017 Sep.
Artículo en Zh | MEDLINE | ID: mdl-28899477

RESUMEN

Mercaptopurine is a common chemotherapeutic drug and immunosuppressive agent and plays an important role in the treatment of acute lymphoblastic leukemia and inflammatory bowel disease. It may cause severe adverse effects such as myelosuppression, which may result in the interruption of treatment or complications including infection or even threaten patients' lives. However, the adverse effects of mercaptopurine show significant racial and individual differences, which reveal the important role of genetic diversity. Recent research advances in pharmacogenomics have gradually revealed the genetic nature of such differences. This article reviews the recent research advances in the pharmacogenomics and individualized application of mercaptopurine.


Asunto(s)
Antimetabolitos Antineoplásicos/uso terapéutico , Mercaptopurina/uso terapéutico , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Humanos , Mercaptopurina/metabolismo , Metiltransferasas/genética , Farmacogenética , Polimorfismo Genético , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Pirofosfatasas/genética
17.
Soft Matter ; 12(5): 1558-66, 2016 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-26659081

RESUMEN

A series of unexpected thermo-responsive phenomena were discovered in an aqueous solution of the cationic gemini surfactant, 2-hydroxypropyl-1,3-bis(alkyldimethylammonium chloride) (n-3(OH)-n(2Cl), n = 14, 16), in the presence of an inorganic salt. The viscosity change trend for the 14-3(OH)-14(2Cl) system was investigated in the 20-40 °C temperature range. As the temperature increased, the viscosity of the solution first decreased to a minimum point corresponding to 27 °C, and then increased until a maximum was reached, after which the viscosity decreased again. In the 16-3(OH)-16(2Cl) system, the gelling temperature (T(gel)) and viscosity changes upon heating were similar to those in the 14-3(OH)-14(2Cl) system above 27 °C. The reversible conversion of elastic hydrogel to wormlike micelles in the aqueous solution of the 16-3(OH)-16(2Cl) system in the presence of an inorganic salt was observed at relatively low temperatures. Various techniques were used to study and verify the phase-transition processes in these systems, including rheological measurements, cryogenic transmission electron microscopy (cryo-TEM), electric conductivity, and differential scanning calorimetry. The abovementioned phenomena were explained by the formation and destruction of intermolecular hydrogen bonds, and the transition mechanisms of the aggregates were analyzed accordingly.

18.
BMC Infect Dis ; 16: 152, 2016 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-27080231

RESUMEN

BACKGROUND: The recent emergence of azithromycin-resistant (AZM-R) N. gonorrhoeae isolates that have coevolved decreased susceptibility to extended-spectrum cephalosporins has caused great concern. Here we investigated the prevalence of decreased susceptibility to ceftriaxone (CRO(D)) in AZM-R isolates and genetically characterized AZM-R isolates in Guangzhou, China from 2009 to 2013. METHODS: The minimum inhibitory concentration (MIC) of AZM and ceftriaxone was determined using an agar-dilution method. All AZM-R isolates were screened for mutations in 23S rRNA, mtrR and penA genes and genotyped using N. gonorrhoeae multi-antigen sequence typing (NG-MAST). RESULTS: Of the 485 identified N. gonorrhoeae isolates, 445 (91.8%) were isolated from male urethritis subjects, and 77 (15.9%) were AZM-R (MIC ≥ 1 mg/L), including 33 (6.8%) with AZM low-level resistant (AZM-LLR, MIC = 1 mg/L) and 44 (9.1%) with AZM middle-level resistant (AZM-MLR, MIC ≥ 2 mg/L). Significantly more CRO(D) (MIC ≥ 0.125 mg/L) showed in AZM-MLR isolates (43.2%, 19/44) as compared with that in AZM-LLR isolates (18.2%, 6/33) (p < 0.05). For the 23S rRNA, mtrR, penA or combined 23S rRNA/MtrR/penA mutations, no significant difference was found between AZM-LLR isolates and AZM-MLR isolates (P > 0.05); similar results were detected between combined AZM-LLR/CRO(D) isolates and combined AZM-MLR/CRO(D) isolates (P > 0.05). No mutation A2059G or AZM high-level resistant (AZM-HLR, MIC ≥ 256 mg/L) isolate was detected. Among 77 AZM-R isolates, 67 sequence types (STs) were identified by NG-MAST, of which 30 were novel. Most STs were represented by a single isolate. CONCLUSIONS: The AZM-R together CRO(D) isolates are now present in Guangzhou, China, which deserve continuous surveillance and the mechanism of concurrent resistance needs further study.


Asunto(s)
Antibacterianos/farmacología , Ceftriaxona/farmacología , Gonorrea/diagnóstico , Neisseria gonorrhoeae/genética , Azitromicina/farmacología , Proteínas Bacterianas/genética , China/epidemiología , Farmacorresistencia Bacteriana/genética , Genotipo , Gonorrea/epidemiología , Gonorrea/microbiología , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Mutación , Neisseria gonorrhoeae/efectos de los fármacos , Neisseria gonorrhoeae/aislamiento & purificación , Reacción en Cadena de la Polimerasa , ARN Ribosómico 23S/análisis , ARN Ribosómico 23S/genética , Proteínas Represoras/genética , Análisis de Secuencia de ADN , Adulto Joven
19.
Biomed Environ Sci ; 29(4): 254-66, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27241736

RESUMEN

OBJECTIVE: This study explored the correlation of longitudinal changes in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels with the incidence of metabolic syndrome (Mets) based on a dynamic health examination cohort. METHODS: A Mets-free dynamic cohort involving 4541 participants who underwent at least three health examinations from 2006 to 2011 was included in the study. Mets was defined according to the Chinese Medical Association Diabetes Branch definition that included hypertension, obesity, hyperlipidemia, and hyperglycemia. Generalized estimating equation (GEE) model was used to analyze multivariate relative risk (RR) of repeated observations of ALT and AST in quartiles for Mets or its components according to gender. RESULTS: In all, 826 Mets cases were reported. Adjustment of relevant parameters indicated that time-varying changes in ALT and AST levels were positively associated with the incidence of Mets in a dose-response manner. Positive association between high ALT levels and fatty liver was much stronger than that between high AST levels and fatty liver, particularly in male participants. These associations were consistently observed in the following subgroups: participants with ALT and AST levels of <40 U/L, participants with of <25 kg/m2, and participants with non-fatty liver. Furthermore, participants with 2 Mets components at baseline showed lower multivariate adjusted RRs of ALT and AST for Mets than participants with 0-1 Mets component. CONCLUSION: These results suggested that elevated serum ALT and AST levels were early biomarkers of Mets or its components.


Asunto(s)
Alanina Transaminasa/sangre , Aspartato Aminotransferasas/sangre , Hepatitis/complicaciones , Síndrome Metabólico/complicaciones , Síndrome Metabólico/diagnóstico , Adulto , Anciano , Biomarcadores/sangre , China/epidemiología , Estudios de Cohortes , Femenino , Hepatitis/epidemiología , Hepatitis/etiología , Humanos , Incidencia , Hígado/enzimología , Hígado/fisiopatología , Masculino , Síndrome Metabólico/enzimología , Síndrome Metabólico/epidemiología , Persona de Mediana Edad , Adulto Joven
20.
Opt Express ; 22(3): 3578-84, 2014 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-24663648

RESUMEN

An asymmetrical Fabry-Perot interferometric (AFPI) force sensor is fabricated based on a narrowband reflection of low-reflectivity fiber Bragg grating (LR-FBG) and a broadband Fresnel reflection of the cleaved fiber end. The AFPI sensor includes a section of microfiber made by tapering and it achieves a force sensitivity of 0.221 pm/µN with a tapered microfiber of 40 mm length and 6.1 µm waist diameter. Compared with similar AFPI structure in 125 µm-diameter single mode fiber, the force sensitivity of the microfiber AFPI structure is greatly enhanced due to its smaller diameter and can be optimized for different force scales by controlling the diameter. The fabrication process of the AFPI sensor is simple and cost-effective. The AFPI sensor has better multiplexing capacity than conventional extrinsic fiber-optic Fabry-Perot sensors, while it also release the requirement on the wavelength matching of the FBG-pair-based FPI.


Asunto(s)
Tecnología de Fibra Óptica/instrumentación , Interferometría/instrumentación , Refractometría/instrumentación , Transductores de Presión , Diseño de Equipo , Análisis de Falla de Equipo , Miniaturización , Estrés Mecánico
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA