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Vitamin D deficiency and insufficiency is a global health issue that afflicts people of different age groups all over the world. As a reliable indicator for the evaluation of vitamin D, 25OHD is usually determined by LC-MS/MS. The tandem mass spectrometry based on ion trap has the characteristics of simple structure and high sensitivity. However, there are some problems such as narrow linear range and space charge effect, which limit its analysis of trace substances in complex matrix samples. In this study, the device and technology of a new quadrupole linear ion trap mass spectrometry was used to reduce the space charge interference of trace or ultra trace target ions by high abundance impurity ions in complex matrices. For the first time, isotope dilution mass spectrometry for accurate measurement of serum 25OHD was established by QLIT-6610MD, which is quadrupole-linear ion trap tandem mass spectrometer, and was independently developed by Technology Innovation Center of Mass Spectrometry for State Market Regulation, Center for Advanced Measurement Science, National Institute of Metrology. Serum samples were precipitated with methanol, extracted with n-hexane, dried with liquid nitrogen, redissolved in the initial mobile phase, and determined by QLIT-6610MD. The matrix-matched standard curve was used for quantification. The linear ranges of 25OHD2 and 25OHD3 were in the range of 0.78-50 μg/L and 1.56-100 μg/L with R2>0.999 9, respectively. The detection and quantification limits of 25OHD2 and 25OHD3 were 0.06, 0.12 μg/L and 0.02, 0.06 μg/L, respectively. The precision of quality control was better than 4.06%. The recoveries ranged from 99.25% to 108.38%, and the coefficients of variation were all less than 5.1%. After the method confirmation, the quantitative results of clinical samples were compared with triple quadrupole tandem mass spectrometry. 50 Clinical serum samples were measured and compared by QLIT-6610MD, AB 4500MD and YS EXACT 9900MD. The correlation and consistency of the data were analyzed by Pearson and Bland-Altman. The correlation coefficient of the three groups data was R≥0.998 0, P

Millimeter‐wave dielectric characteristrics of Sr1−xCaxSmAlO4 ceramics were investigated together with their structures. The solid solution in the space group I4/mmm was determined in the entire composition range, and the excellent microwave dielectric characteristics were not only obtained in the centimeter‐wave range but also in the millimeter‐wave range. The dielectric constant εr indicated a slight decrease from 19.5, and the significantly improved Q×f value was achieved, while the temperature coefficient of resonant frequency τf became more negative (from −3.4 to −12 ppm/°C) with increasing x. Q×f value showed apparent increase with increasing frequency, and the Q×f value at 28 GHz was improved from 88 000 to 160000 GHz with increasing x. The best combination of millimeter‐wave dielectric characteristics was achieved at x = 0.6: εr = 19, Q×f = 143 300 GHz (at 27.3 GHz), and τf = −9.3 ppm/°C. The present ceramics could be expected as the promising candidates as millimeter‐wave dielectric ceramics. [ABSTRACT FROM AUTHOR]

C7H17Cl2N2NaO9, orthorhombic, Pbca (no. 61), a = 13.907(3) Å, b = 10.927(2) Å, c = 19.194(4) Å, V = 2916.8(10) Å3, Z = 8, Rgt(F) = 0.0472, wRref(F2) = 0.1129, T = 298 K.

Recently, hexagonal rare earth ferrites (h-RFeO3) have attracted much scientific attention due to their room-temperature multiferroicity. The primary issue for h-RFeO3 is how to manipulate from nonpolar orthorhombic (Pbnm) structure to polar hexagonal (P63cm) structure, and this could be realized by the wet-chemical method, epitaxial stain engineering, or introducing chemical pressure. Another key issue for h-RFeO3 is the experimental determination of its macroferroelectricity and magnetoelectric (ME) coupling because the semiconducting nature seriously obstructs the experimental characterization. In the present work, owing to the suppressed leakage current density with decreasing temperature, saturated electrical hysteresis loops were observed in A-site substituted h-Lu0.5In0.5FeO3 ceramics at 198 K, directly demonstrating the presence of the macroferroelectricity. Room-temperature switchable ferroelectric polarization was further confirmed by the piezoresponse force microscopy. Furthermore, noticeable ME coupling with a linear ME voltage coefficient of 0.67 mV/cm Oe was observed at room temperature. [ABSTRACT FROM AUTHOR]

SmFeO3 has received the increasing scientific attention as a promising room‐temperature single‐phase multiferroic material with great application potential in the next‐generation spintronic devices. However, the ferroelectricity of SmFeO3 has remained as a controversial issue. In the present work, high resistivity incipient ferroelectric CaTiO3 was introduced as a charge blocking layer on an SmFeO3 thin film to suppress the leakage current. CaTiO3/SmFeO3/Nb–SrTiO3 (1 0 0) thin films were prepared by a PLD (pulsed laser deposition) process, and the epitaxial growth of thin films was confirmed by XRD (X‐ray diffraction) and HRTEM (high resolution transmission electron microscope) images. The interface strain resulted in the polar non‐centrosymmetry in space group P42/mc for SmFeO3, and subsequently the room‐temperature ferroelectricity was achieved with a robust remanent polarization of about 4.9 μC/cm2. The 180° switchable domain structure was confirmed by PFM (piezoelectric force microscope). Meanwhile, strong magnetoelectric coupling with magnetoelectric coefficient (αME) of about 2.5 V/(cm Oe) was observed. The present work has revealed the structural origin of ferroelectricity in an SmFeO3 thin film and provided the great reference for its room temperature multiferroic applications. [ABSTRACT FROM AUTHOR]

ABSTRACT It is well known that financial asset returns have a non-normal distribution and are leptokurtic, with the tails fatter than those of the normal distribution. The Standard EWMA estimator [...]

The Epstein-Barr virus may cause some cases of nose cancer, according to a study of 9,699 men who were tested for antibodies against the virus and then followed for up to 15 years. Those who had antibodies to the virus in their blood at the start of the study were 33 times more likely to develop nose cancer than those who had no viral antibodies.

Hexagonal rare‐earth ferrites (h‐RFeO3) have attracted much scientific attention due to their room‐temperature multiferroicity. However, it is still a hard job to obtain h‐RFeO3 bulk materials because of the meta‐stability of such hexagonal phase, and the evaluation of room‐temperature ferroelectric and magnetoelectric characteristics in such materials is also a challengeable issue. In the present work, Yb1−xInxFeO3 ceramics with the stable hexagonal structure were obtained by introducing chemical pressure, where the unique ferroelectric domain structures of sixfold vortex combined with tenfold vortex with a typical size of ~400 nm were determined. Symmetry of the present system evolved from centrosymmetric orthorhombic Pbnm (x = 0–0.4) to non‐centrosymmetric hexagonal P63cm (x = 0.5 and 0.6) with a ferroelectric polarization up to 3.2 μC/cm2, and finally to centrosymmetric hexagonal P63/mmc (x = 0.7 and 0.8). The Curie point decreased monotonically from 723 K to a temperature below room temperature with increasing x, and the antiferromagnetic phase transition above room temperature was determined for all compositions. Meanwhile, a large linear magnetoelectric coefficient (αME) up to 0.96 mV/cm Oe was obtained at room temperature, and this indicated the great application potential for magnetoelectric devices. [ABSTRACT FROM AUTHOR]