101,957 research outputs found
UHPLC-ESI-QTOF-MS profile of polyphenols in Goji berries (Lycium barbarum L.) and its dynamics during in vitro gastrointestinal digestion and fermentation
No full textThe phenolic profile of Goji berries from Italy and China was investigated through ultra-high-pressure liquid
chromatography coupled with quadrupole-time-of-flight mass spectrometry. Hydroxycinnamic acids, followed
by flavonols and flavanols, were the most representative phenolics, whereas glycoside forms of anthocyanins and
flavonols were the compounds best discriminating between Chinese and Italian berries.
A mix of dried berries was then subjected to in vitro gastro-intestinal digestion and fermentation to investigate
the fate and bioaccessibility of phenolic compounds. The total phenolic content and the oxygen radical absorbance
capacity recorded during the large intestine fermentation increased at 24 h, up to 1.56 mg gallic acid
equivalents g−1 and 1.76 μmol trolox equivalents g−1, respectively. Multivariate statistics applied to phenolic
profiling during the in vitro fermentation depicted those compounds having the highest bioaccessibility; stilbenes,
alkyl-resorcinols and lignans were the best markers of Goji berries during in vitro fermentation
Concentration and grain-size of dust particles from ice sections of the Talos Dome ice core (East Antarctica)
No full textCoulter counter data about concentration and grain-size of dust particles from ice sections of the Talos Dome ice core. They have been partially (from the surface to the depth of 900 m) already been published (Baccolo et al. 2018, Albani et al. 2012). For each sample 2 or 3 measurements were carried out and the average value is reported. Data were linearly interpolated and re-sampled with a spatial resolution of 1 m. Concentrations are expressed as ppb, i.e. ngdust g-1ice. The AICC2012 chronolgy has been used (Veres et al. 2013, Bazin et al. 2013)
Mineralogical study of rodingitized microgabbros and associated chromitite seams from the Nain ophiolite, Central Iran
No full textThe Nain-Dehshir-Baft Ophiolitic Belt (NDBOB), which crops out along the Nain-Baft fault, around the Central Iranian Microcontinent (CIM), comprises a set of dismembered ultramafic, mafic and sedimentary complexes.
The northernmost branch of this ophiolitic belt is known as “Nain ophiolitic mélange” and hosts small chromitite bodies, as pods and lenses, within completely serpentinized peridotites.
The focus of the present study is the interaction between a 50 cm thick chromitite lens and a crosscutting rodingite dyke. For this purpose, a full transect across chromitite, rodingite and serpentinite was continuously sampled and studied in reflected and transmitted light microscopy. Mineral chemistry of sulfides, silicates, carbonates and oxydes was determined through EMP analyses.
Rodingite shows a calc-silicate assemblage with an association of clinopyroxene, xonotlite, chlorite, garnet, vesuvianite, titanite, hornblende and chromite. Chromitite has 60-80% modal chromite, that sporadically shows a slight Fe-chromitization. Silicate assemblage is dominated by serpentine with relics of olivine and, occasionally, diopside, enstatite, hornblende and phlogopite. Later calcite veins crosscut both rodingite and chromitite, extending within serpentinite too.
Rodingite shows a widespread range of copper sulfides, the most common ones being chalcocite, followed by native copper, digenite, geerite, and few spotted grains of possible yarrowite and sponkiopite. As secondary Cu oxydes and hydroxydes tenorite and spertiinite were found.
In chromitite, close to the upper contact with rodingite, usual secondary sulfides like heazlewoodite and millerite were found together with shandite. Close to the lower rodingite contact, the presence of pyrrhotite, native iron and pentlandite was detected. Very close to the lower contact, again an unusual sulfide assemblage was found, with bornite and galena.
Within rodingite clinopyroxenes show both diopside and augite compositions, with XMg ((Mg/(Mg+Fe2+)) of 0.93-0.96 for the former and 0.82-0.86 for the latter. Garnets are grossular and hydrogrossular in the upper rodingite, to which andradite is added in the lower rodingite. Chlorite shows a wide range of compositions with XMg increasing towards the contact with chomitite from 0.47 to 0.60. Very close to the contact XMg of chlorite ranges between 0.67 and 0.94. Chromite accessory grains have XMg ranging between 0.52 and 0.68 and XCr (Cr/(Cr+Al)) ranging between 0.75 and 0.80.
Chromite in chromitite has XMg ranging between 0.65 and 0.71 and XCr ranging between 0.68 and 0.71. Olivine is forsteritic with XMg ranging between 0.95 and 0.97 and orthopyroxene is enstatitic with XMg around 0.94-0.95.
Chlorite is very rare and has around 3.5 wt% Cr2O3.
Rodingite intrusion postdates serpentinization of mantle assemblage and did not affect the chomite+silicate chromitite assemblage. The effect on sulfide variety and distribution was instead remarkable. At least lead and copper were introduced in the contact zone within chromitite to form shandite and bornite. Reducing conditions during rodingite emplacement are witnessed by the abundance of native copper and the presence of native iron.
The effect of interaction in rodingite is mainly recorded by the wide range of chlorite compostions that increases its Mg content towards chromitite
Mineral dust impact on snow radiative properties in the European Alps combining ground, UAV, and satellite observations
No full textIn this paper, we evaluate the impact of mineral dust (MD) on snow radiative properties in the European Alps at ground, aerial, and satellite scale. A field survey was conducted to acquire snow spectral reflectance measurements with an Analytical Spectral Device (ASD) Field Spec Pro spectroradiometer. Surface snow samples were analyzed to determine the concentration and size distribution of MD in each sample. An overflight of a four-rotor Unmanned Aerial Vehicle (UAV) equipped with an RGB digital camera sensor was carried out during the field operations. Finally, Landsat 8 Operational Land Imager (OLI) data covering the central European Alps were analyzed. Observed reflectance evidenced that MD strongly reduced the spectral reflectance of snow, in particular, from 350 to 600 nm. Reflectance was compared with that simulated by parameterizing the Snow, Ice, and Aerosol Radiation radiative transfer model. We defined a novel spectral index, the Snow Darkening Index (SDI), that combines different wavelengths showing nonlinear correlation with measured MD concentrations (R2= 0.87, root-mean-square error = 0.037). We also estimated a positive instantaneous radiative forcing that reaches values up to 153W/m2for the most concentrated sampling area. SDI maps at local scale were produced using the UAV data, while regional SDI maps were generated with OLI data. These maps show the spatial distribution of MD in snow after a natural deposition from the Saharan desert. Such postdepositional experimental data are fundamental for validating radiative transfer models and global climate models that simulate the impact of MD on snow radiative properties
Increased plasma PCSK-9 is associated with restenosis in patients undergoing carotid endarterectomy
No full textRegression toolbox for MATLAB
No full textThe Regression toolbox for MATLAB is a collection of MATLAB modules for calculating regression multivariate models: Ordinary Least Squares (OLS), Partial Least Squares (PLS), Principal Component Regression (PCR), Ridge regression, local regression based on K Nearest Neighbours (KNN) and Binned Nearest Neighbours (BNN) approaches, and variable selection approaches (All Subset Models, Forward selection, Genetic Algorithms and Reshaped Sequential Replacement).
Help files
HTML files are provided toghter with the MATLAB files in order to help the user. The HTML help provides some underlying information on multivariate regression (see Theory section); it also explains how to prepare your data, how to handle the model settings and how to calculate the regression models. An example of analysis is shown.
Conditions and warranty
The toolbox is freeware and may be used if proper reference is given to the authors. Please, refer to the following paper:
V. Consonni, G. Baccolo, F. Gosetti, R. Todeschini, D. Ballabio (2021) A MATLAB toolbox for multivariate regression coupled with variable selection. Chemometrics and Intelligent Laboratory Systems, 213, 104313 [link]
The Regression toolbox for MATLAB is distributed with an Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence
Dust Transport to the Taylor Glacier, Antarctica, During the Last Interglacial
No full textChanges in the composition of dust trapped in ice provide evidence of past atmospheric circulation and earth surface conditions. Investigations of dust provenance in Antarctic ice during glacial and interglacial periods indicate that South America is the primary dust source during both climate regimes. Here, we present results from a new ice core dust archive extracted from the Taylor Glacier in coastal East Antarctica during the deglacial transition from Marine Isotope Stage 6 to 5e. Radiogenic strontium and neodymium isotopes indicate that last interglacial dust is young and volcanic, in contrast to the observed preindustrial and Holocene (Marine Isotope Stage 1) dust composition. The dust composition differences from the last interglacial and current interglacial period at the site require a profound difference in atmospheric transport and environmental conditions. We consider several potential causes for enhanced transport of volcanic material to the site, including increased availability of volcanic material and large‐scale atmospheric circulation changes.Plain Language SummaryFluctuations in the isotopic composition of dust particles transported atmospherically and trapped in East Antarctic ice during glacial and interglacial periods provide glimpses into past earth surface conditions and atmospheric dynamics through time. Here we present new ice core records of dust from the Taylor Glacier (Antarctica), extending back to the transition into the last interglacial period (~130,000 years ago). Dust deposited at this site during the last interglacial period has a significantly more volcanic dust composition compared to the current interglacial dust, caused by a pronounced wind direction change and/or increased subaerial exposure of volcanic material. The distinct dust compositions during two separate interglacial periods suggest significant differences in conditions at the dust source areas and atmospheric dynamics to this peripheral Antarctic site.Key PointsLast interglacial dust composition in Taylor Glacier ice is distinct from MIS 1 recordSr and Nd isotope signatures indicate a young volcanic sourceGeochemical data suggest a change in provenance and atmospheric circulation between MIS 5e and MIS 1Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148354/1/grl58638_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148354/2/grl58638.pd
Changes in extra-virgin olive oil added with Lycium barbarum L. carotenoids during frying: Chemical analyses and metabolomic approach
No full textIn this work, an Italian extra-virgin olive oil (EVOO) sample and the same sample added with a carotenoid-rich
nutraceutical extract from Lycium barbarum L. (EVOOCar) were subjected to a frying process to comparatively
assess chemical and physical changes and heat stability. Oxidation progress was monitored by measuring oil
quality changes such as peroxide value, free acidity, K232, K268, and fatty acid composition as well as minor
compound content, phenols, α-tocopherol, and carotenoids. An UHPLC/QTOF-MS metabolomics approach
discriminated the two oil samples based on their chemical changes during frying, identifying also the phenolic
classes most exposed to statistically significant variations. Partial least square discriminant analysis and volcano
analysis were applied together to identify the most significant markers allowing group separation. The decrease
in total phenolic content was lower in EVOOCar than in EVOO during frying. Monounsaturated and polyunsaturated
fatty acids showed a significant percentage loss, 3.7% and 17.2%, respectively, in EVOO after
180 min frying at 180 °C, while they remained constant or slightly changed in EVOOCar. Zeaxanthin added to
the oil rapidly decreased during the frying process. These findings showed that the addition of a carotenoid
extract from L. barbarum can help to improve the oxidative stability of extra-virgin olive oil
- …
