Room temperature ferromagnetism in polycrystalline CoxCe1-xO2-delta (0.001 < =x < =0.10) bulk samples has been investigated. Annealing in the forming gas transformed the as-prepared paramagnetic into ...a ferromagnetic insulating material with over two orders of magnitude enhancement (from 3.7 X 10-2 to 1.24 muB/Co) in the magnetization. Structural characterization of both the as-prepared and H2-treated samples showed a single phase material. The incorporation of Co with the formation of oxygen vacancies in the oxide lattice was revealed by x-ray photoelectron spectroscopy (XPS). The presence of oxygen vacancies is indicated by the existence of mixed valence states of cerium (Ce4+ and Ce3+) in the high resolution XPS 3d spectrum. The role of the donor defects (oxygen vacancies) has been verified through the removal of oxygen vacancies. The ferromagnetic insulating ground state has been explained in terms of the interaction of the F+ center and 3d magnetic cations. The connection between magnetic properties, electronic structure of the magnetic impurity and donor defect has been established. First principle calculations have been performed using the full potential linearized augmented plane wave method within the density functional theory (DFT) framework; these support our experimental findings. Both the experiment and calculations reinforced the crucial role of oxygen vacancies.
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•Heteronuclear J-coupling measurements in weak and grossly inhomogeneous magnetic fields.•Analysis of measurement sensitivity and frequency resolution for hydrocarbon ...mixtures.•Preliminary experimental results from a fringe-field setup.
It is difficult to measure chemical shifts in the small and inhomogeneous magnetic fields found in ex situ and single-sided NMR systems, such as those used for well-logging. However, it is still possible to obtain chemical information from J-coupling constants, which are independent of static field strength and temperature. We describe and analyze 1H–13C double-resonance pulse sequences that are suitable for measuring heteronuclear J-coupling in grossly inhomogeneous fields. We also present preliminary experimental results from a low-frequency fringe-field system.
Air–sea interaction at ocean fronts and eddies exhibits positive correlation between sea surface temperature (SST), wind speed, and heat fluxes out of the ocean, indicating that the ocean is forcing ...the atmosphere. This contrasts with larger scale climate modes where the negative correlations suggest that the atmosphere is driving the system. This paper examines the physical processes that lie behind the interaction of sharp SST gradients and the overlying marine atmospheric boundary layer and deeper atmosphere, using high resolution satellite data, field data and numerical models. The importance of different physical mechanisms of atmospheric response to SST gradients, such as the effect of surface stability variations on momentum transfer, pressure gradients, secondary circulations and cloud cover will be assessed. The atmospheric response is known to create small-scale wind stress curl and divergence anomalies, and a discussion of the feedback of these features onto the ocean will also be presented. These processes will be compared and contrasted for different regions such as the Equatorial Front in the Eastern Pacific, and oceanic fronts in mid-latitudes such as the Gulf Stream, Kuroshio, and Agulhas Return Current.
With the unique database from the Michelson Doppler Imager on board the Solar and Heliospheric Observatory in an interval embodying solar cycle 23, the cyclic behavior of solar small-scale magnetic ...elements is studied. More than 13 million small-scale magnetic elements are selected, and the following results are found. (1) The quiet regions dominated the Sun's magnetic flux for about 8 years in the 12.25 year duration of cycle 23. They contributed (0.94-1.44) X1023 Mx flux to the Sun from the solar minimum to maximum. The monthly average magnetic flux of the quiet regions is 1.12 times that of the active regions in the cycle. (2) The ratio of quiet region flux to that of the total Sun equally characterizes the course of a solar cycle. The 6 month running average flux ratio of the quiet regions was larger than 90.0% for 28 continuous months from July 2007 to October 2009, which very well characterizes the grand solar minima of cycles 23-24. (3) From the small to the large end of the flux spectrum, the variations of numbers and total flux of the network elements show no correlation, anti-correlation, and correlation with sunspots, respectively. The anti-correlated elements, covering the flux of (2.9-32.0)X1018 Mx, occupy 77.2% of the total element number and 37.4% of the quiet-Sun flux. These results provide insight into the reason for anti-correlations of small-scale magnetic activity during the solar cycle.
In this paper, Tb(OH)3 and Y(OH)3 single‐crystalline nanotubes with outer diameters of 30–260 nm, inner diameters of 15–120 nm, and lengths of up to several micrometers were synthesized on a large ...scale by hydrothermal treatment of the corresponding oxides in the presence of alkali. In addition, Tb4O7 and Y2O3 nanotubes can be obtained by calcination of Tb(OH)3 and Y(OH)3 nanotubes at 450 °C. X‐ray diffraction (XRD), field‐emission scanning electron microscopy, transmission electron microscopy (TEM), electron diffraction (ED), energy‐dispersive X‐ray spectroscopy (EDS), thermogravimetry, and differential scanning calorimetry (DSC) have been employed to characterize these nanotube materials. The growth mechanism of rare earth hydroxide nanotubes can be explained well by the highly anisotropic crystal structure of rare earth hydroxides. These new types of rare earth compound nanotubes with open ends have uses in a variety of promising applications such as luminescent devices, magnets, catalysts, and other functional materials. Advantages of this method for easily realizing large‐scale production include that it is a simple and unique one‐pot synthetic process without the need for a catalysts or template, is low cost, has high yield, and the raw materials are readily available. The present study has enlarged the family of nanotubes available, and offers a possible new, general route to one‐dimensional single‐crystalline nanotubes of other materials.
Synthesis of single‐crystalline rare earth (Tb, Y) hydroxide nanotubes is demonstrated. Nanotubular structures grow through a dissolution–recrystallization process by hydrothermal treatment of the corresponding bulk crystals in the presence of alkali. Hydroxide nanotubes were calcined in air to produce the corresponding oxide nanotubes (as shown in the scanning electron microscopy (SEM) image, right).
We demonstrate directional output from a deformed disk laser of dimensions comparable to the emission wavelength. Unlike larger deformed cavity lasers, which exhibit universal output directionality ...determined by chaotic ray dynamics, the far-field patterns differ between lasing modes. The directional emission results from weak coupling of isotropic high-quality modes to anisotropic low-quality modes, combined with chiral symmetry breaking of clockwise and counterclockwise propagating waves. This mechanism makes it possible to control the output properties of wavelength-scale lasers.
To explore the applicability of diffusion-tensor imaging (DTI) sequence quantitative parameters in differentiating uterine sarcoma (USr) from degenerative uterine fibroids (DUF).
Fourteen cases of ...USr and 30 cases of DUF were analysed retrospectively. The diffusion-weighted imaging (DWI) and DTI images were analysed by two observers using Functool software on a ADW4.6 workstation. The images were post-processed to generate an apparent diffusion coefficient (ADC) map of DWI, ADC map of DTI (ADCT map), and fractional anisotropy (FA) map. Three regions of interest (ROI) were selected from the ADC, ADCT, and FA maps to obtain the ADC, ADCT, and FA values. The receiver operating characteristic (ROC) curves of all parameters were used to analyse and compare the diagnostic value of USr and DUF.
The ADC value, ADCT value, and FA value of USr (1.190 ± 0.262 × 10−3mm2/s, 1.165 ± 0.270 × 10−9mm2/s, 0.168 ± 0.063) were significantly lower compared to the values for DUF (1.525 ± 0.314 × 10−3mm2/s, 1.650 ± 0.332 × 10−9mm2/s, 0.254 ± 0.111; all p<0.001). The diagnostic threshold values for USr were: ADC ≤1.290 × 10−3mm2/s, ADCT ≤1.322 × 10−9mm2/s and FA ≤0.192. The corresponding sensitivities and specificities were 78.6%/90%, 96.7%/92.9%, and 86.7%/85.7%, respectively. The areas under the curve (AUC) were 0.875, 0.974, and 0.831, respectively.
DTI quantitative parameters can be used to differentiate USr from DUF. The ADCT value had the highest diagnostic efficacy.
•DTI can identify uterine sarcoma (USr) and degenerative uterine fibroids (DUF).•The ADCT and FA values of USr were significantly lower compared to DUF values.•Amongst DTI parameters the ADCT has the high diagnostic efficacy for USr and DUF.
Summary
Objective
This study aimed to examine the secular trends in body mass index (BMI) and waist circumference (WC), and the prevalence of general and abdominal obesity among Chinese children and ...adolescents from 1993 to 2009.
Methods
Data were obtained from the China Health and Nutrition Survey conducted from 1993 to 2009. 9693 children and adolescents aged 6–17 years were included in this study, with their height, weight and WC measured. General obesity was defined using the BMI cut‐offs for overweight recommended by the International Obesity Task Force, and abdominal obesity was assessed when a WC is above the 90th percentile for gender and age.
Results
Among the total participants, mean BMI and WC increased significantly over the period 1993–2009: BMI increased from 17.6 to 17.8 kg m−2, and WC increased from 61.4 to 63.1 cm (both increases P < 0.001). The prevalence of general obesity and abdominal obesity increased significantly over the period: general obesity (including overweight) rose from 6.1% to 13.1% and abdominal obesity from 4.9% to 11.7% (both increases P < 0.001). WC and abdominal obesity increased at a relatively higher rate than BMI and general obesity. Upward trends in the prevalence of general and abdominal obesity were observed in all subgroups of gender, age and region (all increases P < 0.05), except for abdominal obesity in girls aged 13–17 years (P = 0.102).
Conclusion
General and abdominal obesity increased significantly over the past 17 years in Chinese children.
Although many studies have already described the physiological effects of bee products, such as honey, propolis, pollen, and royal jelly, on livestock farming, the health benefits of the honeycomb ...are still not fully understood. The problem of drug residues and bacterial resistance caused by the abuse of antibiotics is becoming increasingly serious. For this reason, a safe, green substitute has to be sought. We conducted a comparative study of honeycomb extract (HE) and an antibiotic on growth performance, carcass traits, immunity, antioxidant function and intestinal microorganisms of yellow bantam broilers. A total of four hundred eighty 21-day-old female yellow bantam broilers were randomly divided into 5 groups of 6 replicates of 16 birds each. The 5 groups were as follows, with birds receiving a basal diet supplemented with 150 ppm (mg/kg) of chlortetracycline (CTE), a basal diet without HE (control group), and a basal diet with 0.1%, 0.15%, or 0.2% HE for 60 days. The results showed that HE addition significantly increased average daily feed intake (ADFI), average daily gain (ADG), decrease feed gain ratio (F/G) from 21 to 80 and 51 to 80 days of age compared to the control group, with all 3 HE addition groups having statistically identical values to the antibiotic group. HE implementation dramatically increased spleen index, serum immunoglobulin A (IgA), immunoglobulin M (IgM,), glutathione peroxide (GSH-Px), superoxide dismutase (SOD), total antioxidant capacity (T-AOC), and total cecum bacteria and Lactobacillus compared to the control group, numerically at the same level as, or even better than, the antibiotic group. HE and CTE both markly reduced serum malondialdehyde (MDA) concentration compared to the control group, with higher concentrations of HE reducing the effect more dramatically than antibiotics. Both HE and CTE significantly raised dressed yield compared to the control group. In summary, HE, as a potential antibiotic alternative, improved growth performance, carcass traits, immune function, serum antioxidant capacity and intestinal microorganisms in yellow bantam broilers. According to the cubic regression analyses, the recommended supplemental dose of HE was calculated to be 0.15 to 0.17% for female yellow bantam broilers between 21 and 80 d of age.
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