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1.
Niger J Clin Pract ; 24(4): 555-560, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33851678

RESUMEN

Objective: The aim of this study is to evaluate the effects of different types of mouthwashes (Klorhexidin, Curasept ADS 205, Meridol, Listerine Cool Citrus) on the surface roughness and color changes of a microhybrid (Point 4), a bulk fill (SonicFill), and a nanohybrid (Nova Compo-N) resin-based composite (RBC). Materials and Methods: Disk-shaped specimens were prepared from tested RBCs and divided into four subgroups which immersed in four different types of mouthwashes. The specimens were subjected to immersion cycles in the mouthwashes and artificial saliva (n = 8). Each cycle consisted of complete immersion in a mouthwash for 21 min and afterwards in saliva for 12 h at 37°C, and this cycle was repeated 8 times. The surface roughness was evaluated using a profilometer and coloration was evaluated using a spectrophotometer before and after immersion time. One-way analysis of variance (ANOVA) for the evaluation of surface roughness data was performed, and interrelation between groups was identified with the Sheffe's multiple comparison test. Results: There were no significant differences between the Ra values of the RBCs before and after immersion in mouthwashes (P > 0.05). There were significant differences between ΔE value of the SF and NCN groups before and after immersion time (P < 0.05). Conclusion: Mouthwashes contribute to oral health, especially in patients at high risk of caries. However, in such patients, patient-specific recommendations should be made when using mouthwashes due to the large number of composite fillings.


Asunto(s)
Resinas Compuestas , Antisépticos Bucales , Color , Humanos , Ensayo de Materiales , Espectrofotometría , Propiedades de Superficie
2.
J Esthet Restor Dent ; 33(2): 323-340, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33769698

RESUMEN

OBJECTIVE: To investigate the color difference using both ΔE*ab and CIEDE2000 formulas of all combinations of all enamel and dentin shades of three different composite systems with three different shade guides, to compare the coverage error (CE) of the shade guides for each composite and to investigate whether coverage error is affected by enamel shade layer thickness (0.5 vs 1 mm). MATERIALS AND METHODS: Disk specimens from all enamel and dentin shades of Essentia, Enamel Plus HRi, and IPS Empress Direct composites were fabricated. Color measurements were performed for all enamel-dentin combinations and for two thicknesses per enamel shade: 0.5 and 1 mm. Color was measured for three shade guides: Vitapan Classical, 3DMaster, and Ivoclar. Minimum color difference between layered composites and shade tabs, closest shade tab match and CE of all shade guides were calculated for all composite shade combinations. RESULTS: In most cases, the closest match was a mismatch. CE of 3DMaster was significantly lower for IPS Empress Direct and Enamel Plus HRi at 0.5 mm enamel thickness. Shade guides exhibited higher lightness values compared to composites and composites lower chroma values compared to shade guides. CONCLUSIONS: Shade guides do not match well to the layered composites. 3DMaster performed better than the other two shade guides, in most cases.


Asunto(s)
Resinas Compuestas , Esmalte Dental , Color , Colorimetría , Coloración de Prótesis , Espectrofotometría
3.
Methods Mol Biol ; 2278: 87-100, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33649950

RESUMEN

The biological significance of conjugated fatty acids (CFAs) has been linked to positive health effects based on biomedical, in vitro, and clinical studies. Of note, conjugated linoleic acids (CLAs) are the most widely characterized fatty acids as geometric isomers cis-9,trans-11 and trans-10,cis-12 CLA occur naturally in ruminant fats, dairy products, and hydrogenated oils. Concerning CLAs, it is known that bacterial biohydrogenation, a process whereby ruminal bacteria or starter cultures of lactic acid bacteria have the ability to synthesize CLA by altering the chemical structure of essential fatty acids via enzymatic mechanisms, produces a multitude of isomers with desirable properties. Bifidobacterium species are classed as food grade microorganisms and some of these strains harness molecular determinants that are responsible for the bioconversion of free fatty acids to CLAs. However, molecular mechanisms have yet to be fully elucidated. Reports pertaining to CLAs have been attributed to suppressing tumor growth, delaying the onset of diabetes mellitus and reducing body fat in obese individuals. Given the increased attention for their bioactive properties, we describe in this chapter the qualitative and quantitative methods used to identify and quantify CLA isomers produced by bifidobacterial strains in supplemented broth media. These approaches enable rapid detection of potential CLA producing strains and accurate measurement of fatty acids in biological matrices.


Asunto(s)
Bifidobacterium/metabolismo , Ácidos Linoleicos Conjugados/metabolismo , Bifidobacterium/química , Técnicas de Cultivo de Célula/métodos , Cromatografía de Gases/métodos , Isomerismo , Ácidos Linoleicos Conjugados/análisis , Espectrofotometría/métodos
4.
Ann Afr Med ; 20(1): 37-41, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33727510

RESUMEN

Context: Some market populations in Nigeria have been shown to have high prevalence of hypertension. Current evidence includes environmental pollutants such as heavy metals as risk factors for hypertension. Aim: To study the heavy metal content of rice meals sold in a market population with a high prevalence of hypertension. Settings and Design: This was a descriptive, cross-sectional study conducted in Ogbete market in Enugu, Southeast Nigeria. Subjects and Methods: Five different cooked rice meals were obtained from 25 locations of the market. The rice meals included jollof rice, white rice and tomato stew, fried rice, white rice and vegetable sauce, and white rice and palm oil stew (ofeakwu). Accompanying protein (meat, fish, and egg) and vegetable salad were excluded. Similar rice meals were homogenized and analyzed in triplicates using spectrophotometric methods for mercury, copper, cadmium, lead, and arsenic determination. Statistical Analysis Used: The mean concentrations of the heavy metals were compared using analysis of variance, and P < 0.05 was considered statistically significant. Results: Twenty-five rice dishes were evaluated, five of each kind. Arsenic content ranged from 503 to 550 mg/kg and was comparable across the five rice dishes (P = 0.148). Copper was significantly highest (16767 mg/kg) in the white rice and tomato stew dish (P < 0.001), while mercury was significantly highest (33 mg/kg) in white rice and ofeakwu (P < 0.001). Jollof rice had the highest cadmium content (23 mg/kg), which was statistically significant (P = 0.021). Lead was not found in any of the rice dishes. Conclusions: Risk factors such as heavy metals may play a role in the high prevalence of hypertension observed in market populations, and rice meals may be a major source of these heavy metals.


Asunto(s)
Hipertensión/epidemiología , Metales Pesados/análisis , Oryza/química , Adulto , Arsénico/análisis , Arsénico/metabolismo , Cadmio/análisis , Cadmio/metabolismo , Estudios Transversales , Femenino , Humanos , Hipertensión/etiología , Masculino , Mercurio/análisis , Mercurio/metabolismo , Metales Pesados/metabolismo , Nigeria , Oryza/metabolismo , Prevalencia , Espectrofotometría
5.
Food Chem ; 351: 129287, 2021 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-33640765

RESUMEN

Broadband acoustic resonance dissolution spectroscopy (BARDS) is a novel method that can be used for the analysis of food-based powders, which are mainly characterized by their composition and particle morphology. This study aimed to evaluate BARDS for the compositional analysis of food powders. The changes in the BARDS spectra due to the changes in composition and particle morphology of fifteen salt mixtures (constituting of NaCl, KCl, and MgCl2) in five particle size ranges were comprehensively studied. Moreover, different regression methods were utilized to estimate each mixture component content. The results revealed that the average time-frequency spectra of each mixture in a certain particle size class were highly distinct and allowed discrimination from others. The unique spectra of each salt mixture originated from the specific dissolution rate and degassing effect of each constitutive compound. Finally, the accurate prediction of each mixture component content confirmed the consistency and efficiency of the method.


Asunto(s)
Análisis de los Alimentos/métodos , Polvos/química , Sales (Química)/análisis , Acústica , Análisis de los Mínimos Cuadrados , Tamaño de la Partícula , Análisis de Componente Principal , Solubilidad , Espectrofotometría
6.
Food Chem ; 351: 129285, 2021 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-33640775

RESUMEN

Macro- and microelement determination in chocolate bars by microwave-induced plasma optical emission spectrometry (MIP OES) was evaluated after microwave-assisted sample digestion. Optimization of the sample digestion was carried out, and the recommended conditions were obtained at a temperature of 190 °C, with a digestion time of 40 min and in a mixture constituted by 2.3 mL of nitric acid, 1.0 mL of hydrogen peroxide and 4.7 mL of water. The method was applied in the analysis of chocolate bars, and the concentration ranges of the elements determined were (in mg kg-1): Ca (653-3096); Cr (<0.6-2.8); Cu (<0.16-19.5); Fe (<1.6-227); Mg (147-2775); K (3554-8573); Mn (<0.03-25.2); Na (45.6-1095); Ni (3.2-10.2); P (1111-22594) and Zn (4.8-33.3). The association of the proposed microwave-assisted acid digestion with the MIP OES technique was adequate for multi-element determination in chocolate bars for routine analysis.


Asunto(s)
Chocolate/análisis , Microondas , Gases em Plasma/química , Espectrofotometría/métodos , Digestión , Calor , Peróxido de Hidrógeno/química , Límite de Detección , Metales/análisis , Ácido Nítrico/química , Agua/química
7.
Sud Med Ekspert ; 64(1): 34-37, 2021.
Artículo en Ruso | MEDLINE | ID: mdl-33511832

RESUMEN

THE AIM OF THE STUDY: Was to investigate the distribution of (±)-N-methyl-3-phenyl-3-(para-trifluoromethyl) phenoxypropylamine hydrochloride (fluoxetine) in the body of warm-blooded animals. For the experiments, Wistar rats were used. Fluoxetine was isolated from animal organs and bio-liquids by liquid-liquid extraction. Thin layer chromatography, UV spectrophotometry, and high performance liquid chromatography were used for identification and quantification. Techniques for isolating fluoxetine from urine, blood, intestinal contents, kidneys, and liver samples using liquid-liquid extraction are presented. Methods for identification and quantitative determination of fluoxetine in extracts by thin layer chromatography, UV spectrophotometry, and high performance liquid chromatography are described. The greatest amount of fluoxetine was found in the kidneys - 12.94±2.18 mg/100 g, the small intestine with contents - 9.50±1.90 mg/100 g and liver - 9.28±1.37 mg/100 g.


Asunto(s)
Fluoxetina , Animales , Cromatografía Líquida de Alta Presión , Cromatografía en Capa Delgada , Fluoxetina/farmacocinética , Ratas , Ratas Wistar , Espectrofotometría , Espectrofotometría Ultravioleta , Distribución Tisular
8.
Artículo en Inglés | MEDLINE | ID: mdl-33429964

RESUMEN

The recent trend in green analytical chemistry is the development of green analytical methods using environmentally friendly solvents. Therefore, three ecofriendly manipulated UV spectroscopic techniques have been validated for the concurrent quantification of newly approved remogliflozin etabonate (REM) and metformin HCl (MET) tablets using water as a solvent. The first method was established using first derivative absorption spectroscopic method by determining the peak amplitude at 233.0 nm for REM and 252.2 nm for MET, a zero crossing of one the component. The second and third methods were based on the peak amplitude difference and first-order derivative absorption of the ratio spectra developed by the manipulation of scanned UV spectra. REM and MET showed good linearity in the series of 1-20 µg ml-1 and 2.5-35 µg ml-1, respectively, by all three methods with an excellent correlation coefficient (r2 ≥ 0.998). Further, the proposed UV spectroscopic techniques were validated as per International Council for Harmonization guidelines. The methods showed good sensitivity, accuracy, and precision. Anticipated procedures were effectively utilized for the concurrent quantification of REM and MET in laboratory prepared mixtures and tablets. The high percent recovery with low standard deviation found for both analytes by all three methods confirms the accuracy and precision of the procedures. Finally, the greenness of the proposed spectroscopic methods, evaluated by semi-quantitative and quantitative methods, showed the eco-friendly nature of the methods. Furthermore, the proposed approaches were simple, accurate, sensitive, economic, and environmentally friendly and hence can be utilized for regular quality control of REM and MET formulation.


Asunto(s)
Metformina , Solventes , Espectrofotometría , Espectrofotometría Ultravioleta , Comprimidos
9.
Sensors (Basel) ; 21(1)2021 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-33466275

RESUMEN

We have augmented a recently introduced method for noninvasive analysis of skin structure and composition and applied it to monitoring of dynamical processes in traumatic bruises. The approach combines diffuse reflectance spectroscopy in visible spectral range and pulsed photothermal radiometry. Data from both techniques are analyzed simultaneously using a numerical model of light and heat transport in a four-layer model of human skin. Compared to the earlier presented approach, the newly introduced elements include two additional chromophores (ß-carotene and bilirubin), individually adjusted thickness of the papillary dermal layer, and analysis of the bruised site using baseline values assessed from intact skin in its vicinity. Analyses of traumatic bruises in three volunteers over a period of 16 days clearly indicate a gradual, yet substantial increase of the dermal blood content and reduction of its oxygenation level in the first days after injury. This is followed by the emergence of bilirubin and relaxation of all model parameters towards the values characteristic for healthy skin approximately two weeks after the injury. The assessed parameter values and time dependences are consistent with existing literature. Thus, the presented methodology offers a viable approach for objective characterization of the bruise healing process.


Asunto(s)
Bilirrubina/análisis , Contusiones/diagnóstico , Contusiones/terapia , Tratamiento de Radiofrecuencia Pulsada , Radiometría/métodos , Piel/fisiopatología , Bilirrubina/metabolismo , Contusiones/metabolismo , Femenino , Humanos , Masculino , Oxígeno/sangre , Piel/metabolismo , Espectrofotometría , beta Caroteno
10.
Food Chem ; 346: 128961, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33454576

RESUMEN

OBJECTIVE: To assess the levels of heavy metals and their antagonists in dairy products available in the markets of São Luís, northeastern Brazil. METHODS: Chemical analysis of the heavy metals copper(Cu), lead(Pb), mercury(Hg), and nickel(Ni) and their antagonists iron(Fe), zinc(Zn), calcium(Ca), selenium(Se), and cobalt(Co) contained in dairy products using inductively coupled plasma optical emission spectrometry (ICP-OES). RESULTS: The main heavy metal observed in dairy products were Hg; Pb; Se and Ni. A significant negative correlation was observed between the concentrations of Cu and Fe (rho = -0.634, p = 0.001), Cu and Zn (rho = -0.794, p = 0.000) in whole milk. A non-significant positive correlation was observed between Pb and Ca (rho = 0.387, p = 0.056), and Hg and Se (rho = 0.055, p = 0.795). CONCLUSIONS: Dairy product brands available in the markets of São Luís could be considered a source of heavy metal contamination (Hg, Pb, Se, Cu, Ni) with weak correlations with their antagonists.


Asunto(s)
Metales Pesados/análisis , Leche/química , Espectrofotometría/métodos , Animales , Brasil , Niño , Cobre/análisis , Productos Lácteos/análisis , Humanos , Mercurio/análisis , Níquel/análisis , Medición de Riesgo , Espectrofotometría/instrumentación , Zinc/análisis
11.
Methods Mol Biol ; 2240: 119-124, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33423231

RESUMEN

Acetylcholinesterase (AChE) is a useful biomarker for organophosphate and carbamate pesticides exposure. The inhibition of this enzyme has been associated with neurotoxicity and alterations at higher levels of biological organization, such as behavior and development impairments. In this chapter, we describe the methodologies for analyses of AChE activity in pools of 96 h of embryos of zebrafish (Danio rerio) using a spectrophotometric method adapted to 96-well microtiter plates.


Asunto(s)
Acetilcolinesterasa/metabolismo , Proteínas de Pez Cebra/metabolismo , Pez Cebra/metabolismo , Animales , Biomarcadores/metabolismo , Larva/enzimología , Espectrofotometría/instrumentación , Factores de Tiempo , Pez Cebra/embriología
12.
Food Chem ; 348: 129053, 2021 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-33508600

RESUMEN

A combination of switchable-hydrophilicity liquid-liquid microextraction prior to magnetic nanoparticle-based dispersive solid-phase microextraction is proposed for the determination of erythrosine using UV/Vis spectrophotometry at 520 nm. Under optimum conditions (i.e., 1.0 mL octylamine as the extraction solvent, 1.5 mL of 10.0 M sodium hydroxide as the phase separation trigger, pH 4.0, 750 µL of acetone as the eluent, 10.0 mg of Fe3O4@XAD-16 as the adsorbent, and 15.0 mL of the sample solution), the method showed a superior analytical performance with limits of detection less than 25.9 ng mL-1, limits of quantitation less than 86.3 ng mL-1 and linear dynamic ranges ranging between 86.3 and 1000 ng mL-1. Percentage relative standard deviations were less than 4.1 and 7.2% for intra-day and inter-day, respectively. The method was successfully applied for the extraction and determination of erythrosine in food samples and other consumer products with recoveries in the range of 94.6-103.9% and within extraction time of 7.8 min per sample.


Asunto(s)
Eritrosina/análisis , Eritrosina/aislamiento & purificación , Análisis de los Alimentos/métodos , Microextracción en Fase Líquida/métodos , Nanopartículas de Magnetita/química , Microextracción en Fase Sólida/métodos , Solventes/química , Interacciones Hidrofóbicas e Hidrofílicas , Límite de Detección , Hidróxido de Sodio/química , Espectrofotometría
13.
Molecules ; 26(3)2021 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-33499107

RESUMEN

This paper presents the results of an investigation into the photooxidation of tocopherols (Tocs) dissolved in argonated and non-argonated n-hexane. During irradiation, steady-state absorption and fluorescence spectra as well as lifetimes were measured. In all experiments, the photoreactions were of the first order type. The reaction rate was higher for all Tocs in argonated solvent. A new emission band with a maximum at 298 nm as well as new absorption and fluorescence bands beyond the 300 nm connected with charge-transfer (C-T) complexes for all Tocs appeared during the irradiation of γ- and δ-Toc. The above results indicate that the photooxidation process is very complex and that the observed phenomena strongly depend on the number and position of methyl groups in the chromanol ring.


Asunto(s)
Hexanos/química , Tocoferoles/química , Tocoferoles/efectos de la radiación , Argón/química , Dimerización , Depuradores de Radicales Libres/química , Oxidación-Reducción , Procesos Fotoquímicos , Solventes , Espectrometría de Fluorescencia , Espectrofotometría , Estereoisomerismo , Rayos Ultravioleta
14.
Molecules ; 26(3)2021 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-33499352

RESUMEN

Green synthesis of nanoparticles using citrus peel extracts is known to be environmentally friendly and non-toxic when compared to chemical methods. In this study, different citrus peel extracts obtained with the solvents acetone and distilled water were used to synthesize copper oxide nanoparticles (CuONPs). The nanoparticles were characterized using cyclic voltammetry, ultraviolet-visible spectroscopy, energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The absorption spectrum of CuONPs prepared with acetone exhibited characteristic peaks at the wavelengths between 280-293 nm, while those with distilled water had peaks at 290 nm. The acetone-synthesized CuONPs were spherical while those produced using distilled water were rod-shaped. Based on EDS, the analysis revealed a trace spectrum of CuO nanoparticles with different weight compositions that varied with the type of citrus peel and solvent used. FTIR measurements were carried out in the range of 500-4000 cm-1 for citrus peel extract mediated CuONPs. The spectra had five vibrations occurring at approximately 473, 477, 482, 607 and 616 cm-1 for all samples, which can be attributed to the vibrations of CuO, validating the formation of highly pure CuONPs.


Asunto(s)
Antibacterianos/química , Antibacterianos/farmacología , Citrus/química , Cobre/química , Cobre/farmacología , Nanopartículas del Metal/química , Farmacorresistencia Bacteriana/efectos de los fármacos , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Gramnegativas/patogenicidad , Bacterias Grampositivas/efectos de los fármacos , Bacterias Grampositivas/patogenicidad , Tecnología Química Verde , Humanos , Nanopartículas del Metal/ultraestructura , Microscopía Electrónica , Extractos Vegetales/química , Extractos Vegetales/farmacología , Espectrometría por Rayos X , Espectrofotometría , Espectroscopía Infrarroja por Transformada de Fourier
15.
Int J Mol Sci ; 22(2)2021 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-33466834

RESUMEN

The hierarchical self-assembling kinetics of the porphyrin 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (H2TPPS44-) into J-aggregates at high ionic strength under acidic conditions and eventually in the presence of an added chiral templating agent (tartrate) were investigated through UV/Vis spectroscopy, resonance light scattering, and circular dichroism (CD). The effect of changing the mixing order of the various components in the solution on the kinetic parameters and the expression of chirality on the final J-aggregates was evaluated. In this latter case, only when the chiral tartrate anion is premixed with the porphyrin, the resulting nano-architectures exhibit CD spectra that reflect the handedness of the chiral inducer. We discuss a general mechanistic scheme, with the involvement of ion pairs or dimers that offer an alternative pathway to the aggregation process.


Asunto(s)
Modelos Químicos , Polímeros/química , Porfirinas/química , Agua/química , Dicroismo Circular , Cinética , Solubilidad , Espectrofotometría , Estereoisomerismo , Tartratos/química
16.
Food Chem ; 340: 128156, 2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-33011465

RESUMEN

The Berthelot reaction for ammonia is revisited with the aim of miniaturization and addressing interferences as encountered with food and water samples. Headspace single drop microextraction of ammonia in phosphoric acid served to attain selectivity in complex matrices, and liquid-liquid microextraction of red or blue indophenol species into 1-octanol-isooctane (60:40, v/v) resulted into high sensitivity. Fiber-optics-based cuvetteless micro-spectrophotometry has been used for colorimetric determination on microliter volumes of extract. The linear dynamic range, limit of detection and enrichment factor have been found to be 0.2-3 mg kg-1, 0.14 mg kg-1 and 38, respectively, measuring red species for milk, cheese and beer (4.9-5.5% error; 4.8-6.3% RSD; n = 5); and 5-400 µg L-1, 0.4 µg L-1 and 137, respectively, measuring blue species for water samples (3.3-5.7% error; 3.6-6.8% RSD; n = 5). A plausible reaction scheme has been proposed for nitroprusside catalysis in indophenol reaction.


Asunto(s)
Amoníaco/análisis , Indofenol/química , Espectrofotometría/métodos , Agua/química , Amoníaco/aislamiento & purificación , Cerveza/análisis , Tecnología de Fibra Óptica , Análisis de los Alimentos/métodos , Límite de Detección , Microextracción en Fase Líquida , Teoría Cuántica
17.
Food Chem ; 338: 128028, 2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-33091983

RESUMEN

Direct determination of arsenic species in real samples is challenging due to their trace concentration and spectral interferences by coexisting ions. Herein, we proposed an ultrasound-assisted dispersive solid phase microextraction (DSPME) procedure for the analyses of the trace inorganic arsenic. The hydrothermally synthesized cadmium sulfide nanoparticles (CdS NPs) completely adsorbed both arsenic species within 20 s at the initial arsenic concentration of 100 µg L-1. The detection limit (3 S/m) of the proposed method was found to be 0.5 ± 0.2 and 0.8 ± 0.2 ng L-1 for As(III) and As(V), respectively. The accuracy of the method against the systematic and constant errors was confirmed by the analysis of the Standard Reference Material (SRM) (>95% recovery with <5% RSD). The Student's t-test values were found to be less than the critical Student's t value at a 95% confidence level. The method was successfully employed for the determination of arsenic in food samples.


Asunto(s)
Arsenicales/análisis , Análisis de los Alimentos , Nanopartículas/química , Espectrofotometría/métodos , Adsorción , Arsenicales/aislamiento & purificación , Compuestos de Cadmio/química , Humanos , Concentración de Iones de Hidrógeno , Microextracción en Fase Sólida , Sonicación , Sulfuros/química
18.
Food Chem ; 339: 127848, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-32871302

RESUMEN

This work aimed to study long-term impact of micro-oxygenation and/or different aging treatments: (i) high SO2, (ii) high Fe with Cu and (iii) gelatin fining on Plavac mali red wine phenolic and in-mouthfeel sensory development in barrels and furthermore in bottles. Results showed that outcomes of micro-oxygenation strongly depend on aging treatments. High SO2 concentration during aging in barrels and bottles delayed typical phenolic changes and slightly contributed to astringency and lower color intensity, particularly in wine that was not micro-oxygenated. High metal concentrations and gelatin fining promoted intensive polymerization of proanthocyanins and a lower percentage of prodelphinidins after long-term aging in barrels. Also, flavan-3-ol and anthocyanins transformation rates in micro-oxygenated wines of both treatments significantly differed from their controls. Gelatin fining proved to be a very effective treatment for astringency reduction, particularly when combined with micro-oxygenation, but fined wines after long term aging in bottles showed lower color intensity.


Asunto(s)
Cobre/química , Gelatina/química , Hierro/química , Oxígeno/química , Fenoles/química , Dióxido de Azufre/química , Vino/análisis , Antocianinas/análisis , Antocianinas/química , Cromatografía Líquida de Alta Presión , Flavonoides/análisis , Espectrometría de Masas , Fenoles/análisis , Espectrofotometría , Factores de Tiempo
19.
Carbohydr Polym ; 254: 117280, 2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-33357856

RESUMEN

Polysaccharides have been used widely in many industries, from food technology and mining to cosmetics and biomedical applications. Over recent years there has been growing interest in the development of responsive polysaccharides with unique and switchable properties, particularly systems that display lower-critical solution temperatures (LCSTs). Therefore, in this study we aimed to investigate a novel strategy that would allow the conversion of non-responsive polysaccharides into thermoresponsive polysaccharides with tuneable LCSTs. Through the functionalisation of dextran with alkylamide groups (isopropyl amide, diethyl amide, piperidinyl and diisobutyl amide) using a carbodiimide coupling approach in conjunction with amic acid derivatives, we prepared a library of novel dextrans with various degrees of substitution (DS), which were characterised via nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC). The alkylamide-functionalised dextrans were found to have good solubility in aqueous solutions, with the exception of those having a high DS of large hydrophobic substituents. Determination of the thermoresponsive characteristics of the polymer solutions via UV-vis spectroscopy revealed that the LCST of the alkylamide-functionalised dextrans was highly dependent on the type of alkylamide group and the DS and could be tuned over a large range (5-35 °C). Above the LCST, all of the thermoresponsive alkylamide-functionalised dextrans formed colloidal dispersions with particles sizes ranging from 400 -600 nm, as determined by dynamic light scattering (DLS). In addition, the polymers were found to exhibit a fast and reversible phase transition in solution with narrow hysteresis (∼ 1-5 °C). Finally, the injectability and biocompatibility of the novel thermoresponsive dextrans was confirmed in vivo via subcutaneous and intracranial ventricle injections, with no local or systemic toxicity noted over a 14 d period. Overall, the alkylamide-functionalised dextrans display interesting thermoresponsive properties and trends that may make them useful in biomedical applications, such as drug-delivery.


Asunto(s)
Polisacáridos/química , Alquilación , Amidas/química , Animales , Materiales Biocompatibles/administración & dosificación , Materiales Biocompatibles/química , Materiales Biocompatibles/toxicidad , Cromatografía en Gel , Dextranos/administración & dosificación , Dextranos/química , Dextranos/toxicidad , Dispersión Dinámica de Luz , Ensayo de Materiales , Ratones , Ratones Endogámicos C57BL , Estructura Molecular , Peso Molecular , Resonancia Magnética Nuclear Biomolecular , Tamaño de la Partícula , Transición de Fase , Polisacáridos/administración & dosificación , Polisacáridos/toxicidad , Espectrofotometría , Temperatura
20.
J Chromatogr A ; 1636: 461739, 2021 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-33316566

RESUMEN

Most of lateral flow immunoassay (LFIA) devices rely on gold nanoparticles (GNP) labeled antibodies or other biospecific proteins, to achieve reagent-less color-based detection. GNP size, GNP-protein conjugation level and its stability are crucial points for the development of precise and accurate methods. In addition, the purification of the GNP-protein conjugates from unreacted protein and GNP, is necessary for adequate analytical performance of the assay. To assist the synthesis and production process of GNP and their protein conjugates, we use for the first time a non-destructive, particle separation-multi-detection approach based on miniaturized flow field flow fractionation (HF5). A separation method was developed to baseline size-separate GNP, GNP-protein, protein and GNP including BSA used as a surface coater in less than 30 minutes. Freshly synthesized GNP were first characterized and then conjugated with two different model antibodies: a mouse immunoglobulin (IgG) and a fluorescein-labeled mouse immunoglobulin (FITC-IgG). The IgG-GNP complexes were fractionated using the HF5 apparatus, able to separate IgG-GNP from free proteins by their hydrodynamic size, allowing purification of the conjugation product. Both IgG-GNPs and GNPs were characterized according to their size by the MALS detector, and according to their Surface Plasmon Resonance and spectrum by UV-Vis detection, improving the results obtained via batch characterization. This simple non-invasive approach is very useful for the LFIA development and optimization: the use of HF5-mutidetection offers a unique tool for this purpose facilitating the industrialization of the process and the relate optimization and standardization.


Asunto(s)
Anticuerpos/química , Fraccionamiento de Campo-Flujo/métodos , Oro/química , Inmunoglobulina G/química , Nanopartículas del Metal/química , Animales , Fluoresceína/química , Ratones , Espectrofotometría , Resonancia por Plasmón de Superficie
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