Several studies have been focused on the effect of milk protein genetic variants on milk physicochemical properties and functionality in recent years. β-casein, an important protein related to milk ...processibility, has been reported to have 2 main genetic variants A
and A
, for which cows may be homozygous or heterozygous. In this study, several physicochemical properties of milk with β-casein variants A
A
, A
A
, and A
A
from 3 collection occasions were analyzed. Higher manganese content and lower pH were found to be associated with the A
A
variant compared with the other 2 genotypes. Better rennet and acid coagulation were found in A
A
milk compared with A
A
and A
A
milk (although P > 0.05), whereas A
A
milk was more stable to creaming compared with the other 2 genotypes, which may be linked to its smaller fat globule size. Thus, milk from cows with A
A
genotype could be preferable for cheese making, while that with A
A
variant can be used in formulations requiring good stability against creaming, and for example, yogurt making, where the softer yogurt texture may be easier to digest.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Context. Asteroseismology is an efficient tool not only for testing stellar structure and evolutionary theory but also constraining the parameters of stars for which solar-like oscillations are ...presently detected. As an important southern asteroseismic target τ Ceti, is a metal-poor star. The main features of the oscillations and some frequencies of τ Ceti have been identified. Many scientists propose to comprehensively observe this star as part of the Stellar Observations Network Group. Aims. Our goal is to obtain the optimal model and reliable fundamental parameters for the metal-poor star τ Ceti by combining all non-asteroseismic observations with these seismological data. Methods. Using the Yale stellar evolution code (YREC), a grid of stellar model candidates that fall within all the error boxes in the HR diagram have been constructed, and both the model frequencies and large- and small- frequency separations are calculated using the Guenther’s stellar pulsation code. The \hbox{$\chi^{2}_{\rm \nu c}$}χνc2 minimization is performed to identify the optimal modelling parameters that reproduce the observations within their errors. The frequency corrections of near-surface effects to the calculated frequencies using the empirical law, as proposed by Kjeldsen and coworkers, are applied to the models. Results. We derive optimal models, corresponding to masses of about 0.775–0.785 M⊙ and ages of about 8–10 Gyr. Furthermore, we find that the quantities derived from the non-asteroseismic observations (effective temperature and luminosity) acquired spectroscopically are more accurate than those inferred from interferometry for τ Ceti, because our optimal models are in the error boxes B and C, which are derived from spectroscopy results.
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The Grand Canal, also known as the Beijing-Hangzhou Grand Canal, is a UNESCO World Heritage Site and the longest canal in the world. It is an important trunk line of the South-to-North Water ...Diversion Project in China. The contamination status and spatial distributions of perfluoroalky substances (PFASs) in waters of the Grand Canal were investigated. The total concentrations of PFASs (∑PFASs) range from 7.8 ng/L to 218.0 ng/L, with high ∑PFASs occurring in the southern part of the Grand Canal which is located in a highly urbanized and economically developed region. The dominance of PFOA showed a decreasing trend toward north while shorter chain homologue proportions increased in the northern part of the Canal which mainly traverses underdeveloped and rural areas in Eastern China. Positive correlations were observed between ∑PFASs and the population density as well as GDP per capita. Intersection with large rivers may affect the contamination levels and composition of PFASs in the water of the Grand Canal near the intersection sites.
•Perfluorinated alkylated substances in waters of the Grand Canal are investigated.•Concentrations and contributions of PFASs differ in different sections of the Canal.•Intersections with large rivers affect contamination levels and composition of PFASs.
The impacts of urbanization and economic development on concentrations and compositions of PFASs in waters of different sections of the Grand Canal are discussed.
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The aim of this work was to establish the diltiazem hydrochloride release mechanism from the chitosan−alginate matrix tablet (MCB/AS) and chitosan−carrageenan matrix tablet (MCS/CSI). The weight loss ...for MCS/CSI is mainly due to the weight loss of the matrix while for MCB/AS it is mainly due to the diltiazem hydrochloride released from the tablet. Using the Peppa's model the release order for MCS/CSI was n = 1.07 ± 0.13 and for MCB/AS was n = 0.76 ± 0.02. Thus, MCS/CSI has a transport mechanism, and for MCB/AS the drug release mechanism is a combined process of diffusion and relaxation. MCB/AS has an elastic modulus (G‘ = 105 Pa) one order of magnitude higher than MCS/CSI (G‘ = 104 Pa). MCB/AS is able to uptake solvent without disrupting the microstructure due to its high elastic modulus. Instead MCS/CSI showed a quick erosion process, which conducted to the tablet disintegration due to a fast solvent uptake process.
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The phase relation of flare index in the northern and southern hemispheres in the time interval of January 1966 to December 2008 is investigated. It is found that, (1) the flare index in the northern ...hemisphere begin six months earlier than that in the southern one, which should lead to phase asynchrony between them but with a slight effect; (2) the main periods of the flare activity in the two hemispheres slightly differ from each other, which should also lead to phase asynchrony between them; (3) the low-frequency modes of the flare activity can be used to study the varying relationship of long-term solar activities and the high-frequency modes can be considered as the stochastic component that is amplitude modulated.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We present an asteroseismic study of the solar-like stars KIC 11395018, KIC 10273246, KIC 10920273, KIC 10339342, and KIC 11234888 using short-cadence time series of more than eight months from the ...Kepler satellite. For four of these stars, we derive atmospheric parameters from spectra acquired with the Nordic Optical Telescope. The global seismic quantities (average largefrequency separation and frequency of maximum power), combined with the atmospheric parameters, yield the mean density and surface gravity with precisions of 2% and ~0.03 dex, respectively. We also determine the radius, mass, and age with precisions of 2–5%, 7–11%, and ~35%, respectively, using grid-based analyses. Coupling the stellar parameters with photometric data yields an asteroseismic distance with a precision better than 10%. A vsini measurement provides a rotational period-inclination correlation, and using the rotational periods from the recent literature, we constrain the stellar inclination for three of the stars. An Li abundance analysis yields an independent estimate of the age, but this is inconsistent with the asteroseismically determined age for one of the stars. We assess the performance of five grid-based analysis methods and find them all to provide consistent values of the surface gravity to ~0.03 dex when both atmospheric and seismic constraints are at hand. The different grid-based analyses all yield fitted values of radius and mass to within 2.4σ, and taking the mean of these results reduces it to 1.5σ. The absence of a metallicity constraint when the average large frequency separation is measured with a precision of 1% biases the fitted radius and mass for the stars with non-solar metallicity (metal-rich KIC 11395018 and metal-poor KIC 10273246), while including a metallicity constraint reduces the uncertainties in both of these parameters by almost a factor of two. We found that including the average small frequency separation improves the determination of the age only for KIC 11395018 and KIC 11234888, and for the latter this improvement was due to the lack of strong atmospheric constraints.
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Abstract We characterized the effect of acute ischemic stroke on the activation of the hypothalamic–pituitary–adrenal (HPA) axis and evaluated the role of glucocorticoids (GC) in the clinical outcome ...following ischemic stroke. Male spontaneous hypertensive rats underwent permanent middle cerebral artery occlusion (PMCAO) and developed a cortical infarct. At 4 h post-PMCAO or sham operation, serum levels of ACTH and corticosterone (CS) were elevated 5 and 4 fold respectively as compared to controls and then returned to basal levels at 24 h post surgery. In these experimental groups we found also a significant depletion of median eminence (ME)-CRH41 . In adrenalectomized (Adx) rats that underwent PMCAO the degree of motor disability and infarct volume was similar to that of intact rats. Administration of dexamethasone (Dex) to Adx-PMCAO rats significantly improved the motor disability and decreased the infarct volume. However, in sham-Adx with PMCAO, Dex had no effect on these two parameters. In rats with PMCAO or sham-PMCAO, brain production of PGE2 was significantly increased. This effect was further enhanced in Adx-PMCAO rats and significantly inhibited by Dex. In conclusion, activation of the HPA axis following PMCAO is due to stress induced by surgery. This activation is mediated by hypothalamic CRH41 . Absence of endogenous GC or administration of Dex in naïve rats does not alter motor and pathological parameters in the acute stage following PMCAO. In contrast, administration of Dex significantly improved the outcome following cerebral ischemia in Adx rats which may be due to increased glucocorticoid receptors. Brain production of PGE2 does not play an important role in the pathophysiology of the acute phase of cerebral ischemia.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Activities of atmospheric aerosols, bulk deposition fluxes, and undisturbed soil inventories of 7Be were investigated in China's East Asian monsoon zone at various latitudes ranging from 23.8°N to ...43.5°N. The annual latitudinal distributions of 7Be concentrations in aerosols follow a distribution pattern which looks similar to a normal distribution with the maxima occurring in the mid-latitude region. Simultaneous measurements of 7Be at various latitudes suggest that atmospheric circulation may play an important role in the latitudinal distributions of 7Be in surface air. Latitude and wet precipitation are the main factors controlling the bulk 7Be depositional fluxes. Significant seasonal variations in 7Be depositional fluxes in Beijing, a mid-latitude city, were observed with the highest flux in summer and the lowest in winter, whereas less seasonality were found in the high- and the low-latitude cities. The highest 7Be inventory in undisturbed soils in summer also occurred at a mid-latitudinal area in the East Asian monsoon zone. Precipitation is the main factor controlling the 7Be soil inventory in Qingdao with the highest values occurring in autumn followed by summer.
•7Be in atmospheric aerosols, rainfall, and soils were measured at different latitudes.•The annual maxima of 7Be concentrations in aerosols occurred at ∼40°N.•Spring and autumn are seasons of high atmospheric 7Be with maxima at 30°N.•The annual maxima of 7Be deposition fluxes occurred at ∼40°N.•High rainfall in summer is the main cause of higher 7Be soil inventory.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Aims. Element diffusion is a basic physical element transport mechanism which induces the redistribution of chemical elements. Using the asteroseismic method, we study the effects of helium and heavy ...element diffusion on the internal structure and stellar evolution of solar-type stars. We also provide asteroseismic parameters for a grid of models which would be useful for direct comparison with the Kepler mission observations. Methods. We construct a grid of solar-type stellar models with various masses (from 0.8 $M_{\odot}$ to 1.2 $M_{\odot}$) and metallicities (Zi = 0.03, 0.025, 0.02, 0.015, 0.01, 0.005) with and without helium and heavy element diffusion. We compute “second differences” and “small separations” of the solar-metallicity models (Zi = 0.02) to analyze the effects of diffusion on the convection zone, helium abundance and the evolutionary sequence of the star. In order to study the asteroseismic property of models with and without diffusion, we compute the p-mode oscillation frequencies of low-degree modes for a grid of models and construct the $(\langle \Delta\nu_{0} \rangle, \langle d_{02} \rangle)$ asteroseismic diagram. Results. We find that the element diffusion could speed up the evolution of the star, especially in the main sequence. The results show that it could enlarge the convective core and change the base of the convection envelope. In addition, the helium and heavy element diffusion make the models evolve to lower large and small separations in the asteroseismic diagram. This effect is more efficient at lower metallicity.
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Aims. We attempt to develop a new asteroseismic diagram and investigate its characteristics, based on the ratio “r01” of adjacent, average, small separations. Methods. The ratio r01 is defined ...following the asymptotic formula of stellar p-modes. Using the low-degree, theoretical, numerical value of adiabatic frequencies of stellar model, we compute the ratio r01 and construct an additional asteroseismic diagram. Results. The additional asteroseismic diagram, which is similar to the C-D diagram (i.e. the famous asteroseismic HR diagram, so-called Christensen-Dalsgaard diagram), represents a composite of the average, large separations $\langle\Delta\nu\rangle$ and the ratio r01 of the adjacent, small separations. A distinct separation is identified between the effects of varying both mass and age. The diagram can therefore provide information that is complementary to that provided by a C-D diagram, which can be used to estimate directly both the stellar mass and evolutionary state. Interestingly, the age of star can be derived from the new asteroseismic diagram. Furthermore, we investigate the parameter r01, which can be a useful direct indicator of stellar age.
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