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1.
Anal Chem ; 96(1): 170-178, 2024 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-38155534

RESUMEN

Characterization of the elemental distribution of samples with rough surfaces has been strongly desired for the analysis of various natural and artificial materials. Particularly for pristine and rare analytes with micrometer sizes embedded on specimen surfaces, non-invasive and matrix effect-free analysis is required without surface polishing treatment. To satisfy these requirements, we proposed a new method employing the sequential combination of two imaging modalities, i.e., microenergy-dispersive X-ray fluorescence (micro-XRF) and Raman micro-spectroscopy. The applicability of the developed method is tested by the quantitative analysis of cation composition in micrometer-sized carbonate grains on the surfaces of intact particles sampled directly from the asteroid Ryugu. The first step of micro-XRF imaging enabled a quick search for the sparsely scattered and micrometer-sized carbonates by the codistributions of Ca2+ and Mn2+ on the Mg2+- and Fe2+-rich phyllosilicate matrix. The following step of Raman micro-spectroscopy probed the carbonate grains and analyzed their cation composition (Ca2+, Mg2+, and Fe2+ + Mn2+) in a matrix effect-free manner via the systematic Raman shifts of the lattice modes. The carbonates were basically assigned to ferroan dolomite bearing a considerable amount of Fe2+ + Mn2+ at around 10 atom %. These results are in good accordance with the assignments reported by scanning electron microscopy-energy-dispersive X-ray spectroscopy, where the thin-sectioned and surface-polished Ryugu particles were applicable. The proposed method requires neither sectioning nor surface polishing; hence, it can be applied to the remote sensing apparatus on spacecrafts and planetary rovers. Furthermore, the non-invasive and matrix effect-free characterization will provide a reliable analytical tool for quantitative analysis of the elemental distribution on the samples with surface roughness and chemical heterogeneity at a micrometer scale, such as art paintings, traditional crafts with decorated shapes, as well as sands and rocks with complex morphologies in nature.

2.
Opt Express ; 31(5): 7983-7993, 2023 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-36859917

RESUMEN

In order to increase the optical path and related sensitivity of photometers, multiple axial-reflection of parallel light-beam inside a capillary cavity is one of the most effective ways. However, there is a non-optimum trade-off between optical path and light intensity, e.g., smaller aperture on cavity mirror can increase multiple axial-reflection times (i.e., longer optical path) due to the lower cavity-loss, but it would also reduce coupling efficiency, light intensity, and related signal-to-noise ratio. Herein, an optical beam shaper, which is composed of two optical lenses with an apertured mirror, was proposed to focus the light beam (i.e., increasing coupling efficiency) without deteriorating beam parallelism and related multiple axial-reflection. Thus, by combining the optical beam shaper with a capillary cavity, large optical path enhancement (10-fold of capillary length) and high coupling efficiency (>65%) can be realized simultaneously, where the coupling efficiency was improved 50-fold. An optical beam shaper photometer (with a 7 cm long capillary) was fabricated and applied to detect water in ethanol with a detection limit of 12.5 ppm, which is 800-fold and 32∼80 fold lower than that of the commercial spectrometer (1 cm cuvette) and previous reports, respectively.

3.
Proc Natl Acad Sci U S A ; 115(41): 10287-10292, 2018 10 09.
Artículo en Inglés | MEDLINE | ID: mdl-30249648

RESUMEN

Hydrosphere interactions and alteration of the terrestrial crust likely played a critical role in shaping Earth's surface, and in promoting prebiotic reactions leading to life, before 4.03 Ga (the Hadean Eon). The identity of aqueously altered material strongly depends on lithospheric cycling of abundant and water-soluble elements such as Si and O. However, direct constraints that define the character of Hadean sedimentary material are absent because samples from this earliest eon are limited to detrital zircons (ZrSiO4). Here we show that concurrent measurements of Si and O isotope ratios in Phanerozoic and detrital pre-3.0 Ga zircon constrain the composition of aqueously altered precursors incorporated into their source melts. Phanerozoic zircon from (S)edimentary-type rocks contain heterogeneous δ18O and δ30Si values consistent with assimilation of metapelitic material, distinct from the isotopic character of zircon from (I)gneous- and (A)norogenic-type rocks. The δ18O values of detrital Archean zircons are heterogeneous, although yield Si isotope compositions like mantle-derived zircon. Hadean crystals yield elevated δ18O values (vs. mantle zircon) and δ30Si values span almost the entire range observed for Phanerozoic samples. Coupled Si and O isotope data represent a constraint on Hadean weathering and sedimentary input into felsic melts including remelting of amphibolites possibly of basaltic origin, and fractional addition of chemical sediments, such as cherts and/or banded iron formations (BIFs) into source melts. That such sedimentary deposits were extensive enough to change the chemical signature of intracrustal melts suggests they may have been a suitable niche for (pre)biotic chemistry as early as 4.1 Ga.


Asunto(s)
Isótopos/análisis , Espectrometría de Masas/métodos , Isótopos de Oxígeno/análisis , Silicatos/análisis , Silicatos/química , Silicio/análisis , Circonio/análisis , Circonio/química , Australia , Sedimentos Geológicos/química , Sudáfrica
4.
Chem Erde ; 79(4)2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32020946

RESUMEN

A coordinated mineralogical and oxygen isotopic study of four fine-grained calcium-, aluminum-rich inclusions (CAIs) from the ALHA77307 CO3.0 carbonaceous chondrite was conducted. Three of the inclusions studied, 05, 1-65, and 2-119, all have nodular structures that represent three major groups, melilite-rich, spinel-rich, and hibonite-rich, based on their primary core mineral assemblages. A condensation origin was inferred for these CAIs. However, the difference in their primary core mineralogy reflects unique nebular environments in which multiple gas-solid reactions occurred under disequilibrium conditions to form hibonite, spinel, and melilite with minor perovskite and Al,Ti-rich diopside. A common occurrence of a diopside rim on the CAIs records a widespread event that marks the end of their condensation as a result of isolation from a nebular gas. An exception is a rare inclusion 2-112 that contains euhedral spinel crystals embedded in melilite, suggesting this CAI had been re-melted. All of the fine-grained CAIs analyzed in ALHA77307 are uniformly 16O-rich with an average Δ17O value of ~-22 ± 5‰ (2σ), indicating no apparent correlation between their textures and oxygen isotopic compositions. We therefore conclude that a prevalent 16O-rich gas reservoir existed in a region of the solar nebula where CO3 fine-grained CAIs formed, initially by condensation and then later, some of them were reprocessed by melting event(s).

5.
J Sci Food Agric ; 98(8): 3057-3065, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29194631

RESUMEN

BACKGROUND: Edible bird's nests (EBNs) have been traditionally regarded as a kind of medicinal and healthy food in China. For economic reasons, they are frequently subjected to adulteration with some cheaper substitutes, such as Tremella fungus, agar, fried pigskin, and egg white. As a kind of precious and functional product, it is necessary to establish a robust method for the rapid authentication of EBNs with small amounts of samples by simple processes. In this study, the Fourier transform infrared spectroscopy (FTIR) system was utilized and its feasibility for identification of EBNs was verified. RESULTS: FTIR spectra data of authentic and adulterated EBNs were analyzed by chemometrics analyses including principal component analysis, linear discriminant analysis (LDA), support vector machine (SVM) and one-class partial least squares (OCPLS). The results showed that the established LDA and SVM models performed well and had satisfactory classification ability, with the former 94.12% and the latter 100%. The OCPLS model was developed with prediction sensitivity of 0.937 and specificity of 0.886. Further detection of commercial EBN samples confirmed these results. CONCLUSION: FTIR is applicable in the scene of rapid authentication of EBNs, especially for quality supervision departments, entry-exit inspection and quarantine, and customs administration. © 2017 Society of Chemical Industry.


Asunto(s)
Análisis de los Alimentos/métodos , Contaminación de Alimentos/análisis , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Animales , Aves , China , Análisis Discriminante , Análisis de Componente Principal , Máquina de Vectores de Soporte
6.
J AOAC Int ; 98(6): 1640-4, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26651577

RESUMEN

The special nutritious value of camel showed high potential for market exploitation. In this paper, a real-time PCR method targeting camel ingredient in camel meat and milk is reported as an approach to fight against adulteration. To understand the impact of processing procedures on the amplifiability of cytb gene, four kinds of processed camel meat were investigated, and the rate of DNA breakage was explored. The method was able to detect 5 fg/µL camel DNA and highly processed food containing 0.01% camel meat with a high confidence level.


Asunto(s)
Camelus , Contaminación de Alimentos/análisis , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Animales , ADN/análisis , Manipulación de Alimentos
7.
Am J Reprod Immunol ; 91(5): e13863, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38796740

RESUMEN

PROBLEM: Hypertensive disorders of pregnancy (HDP) are a common pregnancy disease. NANOG and Cyclin-dependent kinase 1 (CDK1) are essential for regulating the function of cell proliferation and apoptosis. However, the mechanism of action in HDP is yet unclear. METHOD: The microarray dataset GSE6573 was downloaded from the GEO database. Emt-related gene set was downloaded from Epithelial-Mesenchymal Transition gene database 2.0 were screened differentially expressed genes by bioinformatics analysis. Pathway Commons and Scansite 4.0 databases were used to predict the interaction between proteins. Placental tissue samples were collected from HDP patients and patients with uneventful pregnancies. RT-qPCR, Western blot and immunohistochemistry were used to detect the expression of NANOG, CDK1, MMP-2, MMP-9, EMT markers and the JAK/STAT3 pathway proteins. Transfection NANOG overexpression/knockdown, and CDK1 knockdown into the human chorionic trophoblast cells (HTR-8/Svneo). CCK-8, Transwell and Wound-healing assay were used to evaluate cell proliferation, invasion and migration. CO-IP and GST pull-down assays were used to confirm the protein interaction. RESULTS: A total obtained seven EMT-related differentially expressed genes, wherein NANOG, NODAL and LIN28A had protein interaction. In the HDP patients' tissue found that NANOG and CDK1 had lower expression. NANOG overexpression promoted HTR-8/Svneo proliferation, migration and EMT, while NANOG knockdown had the opposite effect. Further a protein interaction between STAT3 and CDK1 with NANOG. NANOG overexpression downregulated the JAK/STAT3 pathway to promote HTR-8/Svneo proliferation, migration and EMT, which was reversed by CDK1 knockdown. CONCLUSIONS: NANOG downregulated the JAK/STAT3 pathway to promote trophoblast cell proliferation, migration and EMT through protein interaction with CDK1.


Asunto(s)
Proteína Quinasa CDC2 , Movimiento Celular , Transición Epitelial-Mesenquimal , Quinasas Janus , Proteína Homeótica Nanog , Factor de Transcripción STAT3 , Transducción de Señal , Trofoblastos , Humanos , Femenino , Factor de Transcripción STAT3/metabolismo , Transición Epitelial-Mesenquimal/genética , Trofoblastos/metabolismo , Embarazo , Proteína Quinasa CDC2/metabolismo , Proteína Quinasa CDC2/genética , Proteína Homeótica Nanog/metabolismo , Proteína Homeótica Nanog/genética , Quinasas Janus/metabolismo , Hipertensión Inducida en el Embarazo/metabolismo , Hipertensión Inducida en el Embarazo/patología , Hipertensión Inducida en el Embarazo/genética , Adulto , Proliferación Celular , Línea Celular
8.
Geobiology ; 22(1): e12576, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-37803496

RESUMEN

The great oxidation event (GOE), ~2.4 billion years ago, caused fundamental changes to the chemistry of Earth's surface environments. However, the effect of these changes on the biosphere is unknown, due to a worldwide lack of well-preserved fossils from this time. Here, we investigate exceptionally preserved, large spherical aggregate (SA) microfossils permineralised in chert from the c. 2.4 Ga Turee Creek Group in Western Australia. Field and petrographic observations, Raman spectroscopic mapping, and in situ carbon isotopic analyses uncover insights into the morphology, habitat, reproduction and metabolism of this unusual form, whose distinctive, SA morphology has no known counterpart in the fossil record. Comparative analysis with microfossils from before the GOE reveals the large SA microfossils represent a step-up in cellular organisation. Morphological comparison to extant micro-organisms indicates the SAs have more in common with coenobial algae than coccoidal bacteria, emphasising the complexity of this microfossil form. The remarkable preservation here provides a unique window into the biosphere, revealing an increase in the complexity of life coinciding with the GOE.


Asunto(s)
Ecosistema , Fósiles , Bacterias , Isótopos de Carbono , Carbono
9.
Nutrients ; 16(9)2024 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-38732536

RESUMEN

Over the past four decades, obesity in children of all ages has increased worldwide, which has intensified the search for innovative intervention strategies. Serious games, a youth-friendly form of intervention designed with educational or behavioral goals, are emerging as a potential solution to this health challenge. To analyze the effectiveness of serious games in improving body composition, physical activity, and dietary change, we performed a systematic review and meta-analysis of randomized controlled trials (RCTs) from PubMed, Web of Science, EMBASE, and Scopus databases. Pooled standardized mean differences (SMD) were calculated for 20 studies (n = 2238 the intervention group; n = 1983 in the control group) using random-effect models. The intervention group demonstrated a slightly better, although non-significant, body composition score, with a pooled SMD of -0.26 (95% CI: -0.61 to 0.09). The pooled effect tends to be stronger with longer duration of intervention (-0.40 [95% CI: -0.96, 0.16] for >3 months vs. -0.02 [95% CI: -0.33, 0.30] for ≤3 months), although the difference was not statistically significant (p-difference = 0.24). As for the specific pathways leading to better weight control, improvements in dietary habits due to serious game interventions were not significant, while a direct positive effect of serious games on increasing physical activity was observed (pooled SMD = 0.61 [95% CI: 0.04 to 1.19]). While the impact of serious game interventions on body composition and dietary changes is limited, their effectiveness in increasing physical activity is notable. Serious games show potential as tools for overweight/obesity control among children and adolescents but may require longer intervention to sustain its effect.


Asunto(s)
Composición Corporal , Ejercicio Físico , Obesidad Infantil , Ensayos Clínicos Controlados Aleatorios como Asunto , Juegos de Video , Humanos , Niño , Adolescente , Obesidad Infantil/prevención & control , Femenino , Masculino , Dieta
10.
Sci Data ; 10(1): 874, 2023 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-38062064

RESUMEN

The UCLA Cosmochemistry Database was initiated as part of a data-rescue and -storage project aimed at archiving a variety of cosmochemical data acquired at University of California, Los Angeles (UCLA). The data collection includes elemental compositions of extraterrestrial materials analyzed by UCLA cosmochemists over the last five decades. The analytical techniques include atomic absorption spectrometry (AAS) and neutron activation analysis (NAA) at UCLA. The data collection is stored on the Astromaterials Data System (Astromat). We provide both interactive tables and downloadable datasheets for users to access all data. The UCLA Cosmochemistry Database archives cosmochemical data that are essential tools for increasing our understanding of the nature and origin of extraterrestrial materials. Future studies can reference the data collection in the examination, analysis, and classification of newly acquired extraterrestrial samples.

11.
Science ; 379(6634): eabn7850, 2023 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-35679354

RESUMEN

Carbonaceous meteorites are thought to be fragments of C-type (carbonaceous) asteroids. Samples of the C-type asteroid (162173) Ryugu were retrieved by the Hayabusa2 spacecraft. We measured the mineralogy and bulk chemical and isotopic compositions of Ryugu samples. The samples are mainly composed of materials similar to those of carbonaceous chondrite meteorites, particularly the CI (Ivuna-type) group. The samples consist predominantly of minerals formed in aqueous fluid on a parent planetesimal. The primary minerals were altered by fluids at a temperature of 37° ± 10°C, about [Formula: see text] million (statistical) or [Formula: see text] million (systematic) years after the formation of the first solids in the Solar System. After aqueous alteration, the Ryugu samples were likely never heated above ~100°C. The samples have a chemical composition that more closely resembles that of the Sun's photosphere than other natural samples do.

12.
Sci Adv ; 9(28): eadh1003, 2023 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-37450600

RESUMEN

Preliminary analyses of asteroid Ryugu samples show kinship to aqueously altered CI (Ivuna-type) chondrites, suggesting similar origins. We report identification of C-rich, particularly primitive clasts in Ryugu samples that contain preserved presolar silicate grains and exceptional abundances of presolar SiC and isotopically anomalous organic matter. The high presolar silicate abundance (104 ppm) indicates that the clast escaped extensive alteration. The 5 to 10 times higher abundances of presolar SiC (~235 ppm), N-rich organic matter, organics with N isotopic anomalies (1.2%), and organics with C isotopic anomalies (0.2%) in the primitive clasts compared to bulk Ryugu suggest that the clasts formed in a unique part of the protoplanetary disk enriched in presolar materials. These clasts likely represent previously unsampled outer solar system material that accreted onto Ryugu after aqueous alteration ceased, consistent with Ryugu's rubble pile origin.


Asunto(s)
Carbono , Meteoroides , Carbono/análisis , Sistema Solar , Silicatos
13.
Sci Adv ; 9(45): eadi7048, 2023 Nov 10.
Artículo en Inglés | MEDLINE | ID: mdl-37939187

RESUMEN

Studies of material returned from Cb asteroid Ryugu have revealed considerable mineralogical and chemical heterogeneity, stemming primarily from brecciation and aqueous alteration. Isotopic anomalies could have also been affected by delivery of exogenous clasts and aqueous mobilization of soluble elements. Here, we show that isotopic anomalies for mildly soluble Cr are highly variable in Ryugu and CI chondrites, whereas those of Ti are relatively uniform. This variation in Cr isotope ratios is most likely due to physicochemical fractionation between 54Cr-rich presolar nanoparticles and Cr-bearing secondary minerals at the millimeter-scale in the bulk samples, likely due to extensive aqueous alteration in their parent bodies that occurred [Formula: see text] after Solar System birth. In contrast, Ti isotopes were marginally affected by this process. Our results show that isotopic heterogeneities in asteroids are not all nebular or accretionary in nature but can also reflect element redistribution by water.

14.
Sci Adv ; 8(50): eade2067, 2022 Dec 16.
Artículo en Inglés | MEDLINE | ID: mdl-36525483

RESUMEN

The extraterrestrial materials returned from asteroid (162173) Ryugu consist predominantly of low-temperature aqueously formed secondary minerals and are chemically and mineralogically similar to CI (Ivuna-type) carbonaceous chondrites. Here, we show that high-temperature anhydrous primary minerals in Ryugu and CI chondrites exhibit a bimodal distribution of oxygen isotopic compositions: 16O-rich (associated with refractory inclusions) and 16O-poor (associated with chondrules). Both the 16O-rich and 16O-poor minerals probably formed in the inner solar protoplanetary disk and were subsequently transported outward. The abundance ratios of the 16O-rich to 16O-poor minerals in Ryugu and CI chondrites are higher than in other carbonaceous chondrite groups but are similar to that of comet 81P/Wild2, suggesting that Ryugu and CI chondrites accreted in the outer Solar System closer to the accretion region of comets.

15.
Sci Adv ; 8(46): eadd8141, 2022 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-36264823

RESUMEN

Little is known about the origin of the spectral diversity of asteroids and what it says about conditions in the protoplanetary disk. Here, we show that samples returned from Cb-type asteroid Ryugu have Fe isotopic anomalies indistinguishable from Ivuna-type (CI) chondrites, which are distinct from all other carbonaceous chondrites. Iron isotopes, therefore, demonstrate that Ryugu and CI chondrites formed in a reservoir that was different from the source regions of other carbonaceous asteroids. Growth and migration of the giant planets destabilized nearby planetesimals and ejected some inward to be implanted into the Main Belt. In this framework, most carbonaceous chondrites may have originated from regions around the birthplaces of Jupiter and Saturn, while the distinct isotopic composition of CI chondrites and Ryugu may reflect their formation further away in the disk, owing their presence in the inner Solar System to excitation by Uranus and Neptune.

16.
Sci Adv ; 7(40): eabg8329, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34586847

RESUMEN

Calcium-aluminum­rich inclusions (CAIs) in meteorites carry crucial information about the environmental conditions of the nascent Solar System prior to planet formation. Based on models of 50V­10Be co-production by in-situ irradiation, CAIs are considered to have formed within ~0.1 AU from the proto-Sun. Here, we present vanadium (V) and strontium (Sr) isotopic co-variations in fine- and coarse-grained CAIs and demonstrate that kinetic isotope effects during partial condensation and evaporation best explain V isotope anomalies previously attributed to solar particle irradiation. We also report initial excesses of 10Be and argue that CV CAIs possess essentially a homogeneous level of 10Be, inherited during their formation. Based on numerical modeling of 50V­10Be co-production by irradiation, we show that CAI formation during protoplanetary disk build-up likely occurred at greater heliocentric distances than previously considered, up to planet-forming regions (~1AU), where solar particle fluxes were sufficiently low to avoid substantial in-situ irradiation of CAIs.

17.
Medicine (Baltimore) ; 99(27): e20927, 2020 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-32629692

RESUMEN

BACKGROUND: The serum albumin, albumin-to-globulin ratio (AGR), and prognostic nutritional index (PNI) have been recommended to represent the nutritional and inflammatory status. Thus, they may be potential prognostic biomarkers for cancer. However, contradictory results were reported in different studies on glioma. The goal of this study was to perform a meta-analysis to re-evaluate their prognostic potential for glioma. METHODS: Databases of PubMed, EMBASE, and Cochrane Library were systematically searched to enroll all the studies investigating the prognostic significance of albumin, AGR, and PNI for glioma. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using STATA 13.0 software to indicate the intensity of association. RESULTS: Eleven studies with 2928 cases were included. Overall meta-analysis showed that the prognostic values of albumin, AGR, and PNI were limited for glioma (P > .05). However, subgroup analysis demonstrated a high preoperative serum albumin was significantly related with excellent OS of patients with GBM (HR = 0.95, 95% CI: 0.91-0.99, P = .018), while high PNI (HR = 0.56, 95% CI: 0.43-0.73, P < .001) and AGR (HR = 0.57, 95% CI: 0.34-0.96, P = .034) may be a protective factor of favorable OS for patients with high-grade gliomas. Furthermore, integration of all studies with multivariate analysis and clear cut-off also proved reduced preoperative serum albumin, AGR, and PNI were predictors of poor prognosis for patients with gliomas. CONCLUSION: Preoperative serum albumin, AGR, and PNI may represent promising biomarkers to predict the prognosis in patients with glioma, especially for high-grade.


Asunto(s)
Neoplasias del Sistema Nervioso Central/sangre , Glioma/sangre , Globulinas/metabolismo , Evaluación Nutricional , Albúmina Sérica/metabolismo , Femenino , Humanos , Masculino , Pronóstico
18.
J Food Sci ; 85(3): 824-833, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32078757

RESUMEN

The crude flavonoid extract of pollen (CFP) of four species of honeybee pollens were extracted with ethanol, and the total flavonoid contents ranged from 3.4 to 14.5 mg rutin/g dry weight. The antioxidant activities of the CFPs were evaluated from both chemical and cytological aspects. Comprehensive antioxidant scores were determined based on these two evaluation systems. The results showed that canola CFP had the highest antioxidant capacity among the four CFPs. A cytotoxicity assay was conducted to assess the safety threshold of the CFPs, and canola CFP was proved to be the least toxic to vascular endothelial cell. Of the four tested CFPs, this research suggests that canola CFP is the most promising natural antioxidant. In addition, high-performance liquid chromatography (HPLC) analysis detected seven flavonoid glycosides in the hydrolysates of the four CFPs. Among them, quercetin and kaempferol were present in all four honeybee pollen extracts, but there were significant differences between their contents. A correlation analysis revealed a strong correlation between the content of quercetin in the pollen extract and the extract's antioxidant activity. PRACTICAL APPLICATION: Many varieties of honeybee pollen are commercially available. The results of this study help guide consumers to choose honeybee pollens that have a better antioxidant effect. This report can also provide guidance and data in support of the development of honeybee pollen health products.


Asunto(s)
Antioxidantes/análisis , Extractos Vegetales/análisis , Polen/química , Animales , Abejas , Cromatografía Líquida de Alta Presión/métodos , Flavonoides/análisis , Glicósidos/análisis , Quempferoles/análisis , Quercetina/análisis , Rutina/análisis
19.
Geochim Cosmochim Acta ; 269: 639-660, 2020 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-32020947

RESUMEN

We carried out a coordinated mineralogical and isotopic study of a Wark-Lovering (WL) rim on a Ca,Al-rich inclusion (CAI) from the reduced CV3 chondrite Vigarano. The outermost edge of the CAI mantle is mineralogically and texturally distinct compared to the underlying mantle that is composed of coarse, zoned melilite (Åk~10-60) grains. The mantle edge contains fine-grained gehlenite with hibonite and rare grossite that likely formed by rapid crystallization from a melt enriched in Ca and Al. These gehlenite and hibonite layers are surrounded by successive layers of spinel, zoned melilite (Åk~0-10), zoned diopside that grades outwards from Al,Ti-rich to Al,Ti-poor, and forsteritic olivine intergrown with diopside. These layered textures are indicative of sequential condensation of spinel, melilite, diopside, and forsterite onto hibonite. Anorthite occurs as a discontinuous layer that corrodes adjacent melilite and Al-diopside, and appears to have replaced them, probably even later than the forsterite layer formation. Based on these observations, we conclude that the WL rim formation was initiated by flash melting and extensive evaporation of the original inclusion edge, followed by subsequent gas-solid reactions under highly dynamic conditions. All the WL rim minerals are 16O-rich (Δ17O = ~-23‰), indicating their formation in an 16O-rich nebular reservoir. Our Al-Mg measurements of hibonite, spinel, and diopside from the WL rim, as well as spinel and Al,Ti-diopside in the core, define a single, well-correlated isochron with an inferred initial 26Al/27Al ratio of (4.94 ± 0.12) × 10-5. This indicates that the WL rim formed shortly after the host CAI. In contrast, the lack of 26Mg excesses in the WL rim anorthite suggest its later formation or later isotopic disturbance in the solar nebula, after 26Al had decayed.

20.
J Am Chem Soc ; 131(11): 3998-4005, 2009 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-19243183

RESUMEN

Mesostructured silica synthesized using cetyltriethylammonium (CTEA) ion as the pore-directing agent in acidic environments was ready to have interfacial anions exchanged at ambient temperature. In situ techniques including small-angle X-ray scattering (SAXS) and optical microscopy were used to examine the structural and morphological changes of the as-made mesostructured materials, and pyrene fluorescence quenching experiment was used to probe the variation in interfacial environment during the anion-exchange processes. About one-half of the interfacial anions between the silica framework and micelle were exchanged based on the fluorescence quenching experiments of pyrene, which was dissolved in the hydrophobic core of the micelle. Altering in the pore structure and the architecture of the silica framework was observed when the interfacial anions were exchanged by anions of higher salting-in power. The resultant phase transformation and morphological change were always toward pore structures of lower curvature. The influence of anion follows the Hofmeister series commonly encountered in macromolecular and biological systems. The mesophase transformation induced by the interfacial anion exchange provides a unique technique to study anions which are not yet included in the Hofmeister series.


Asunto(s)
Transición de Fase , Dióxido de Silicio/química , Micelas , Porosidad
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