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Sr2FeMoO6 ceramics with different Fe/Mo antisite defect (ASD) concentrations and grain-boundary (GB) properties were prepared. The competitive and combining effects of GB and Fe/Mo ASD on the transport and magnetoresistance were discussed. The GB properties, that is, intergrain coupling strength, positively related with resistivity value, is extremely sensitive to the total flux of reducing gas, in general, lower total gas flux leads to larger resistivity, thus stronger intergrain coupling strength, and then the contributions of GB effect to low-field magnetoresistance (LFMR) increase appreciably regardless of the amount of ASD. In detail, when ASD concentration is less than 26%, LFMR is dominantly controlled by the GB effect. However, the suppressed ASD effect on LFMR behavior comes to play when the ASD content is larger than or equal to 26%, where the GB and ASD effects contribute together to the LFMR.

Aim The objectives of this study were to elucidate the phylogenetic origins and phylogeographical history of Ligularia hodgsonii, which exhibits a disjunct distribution between south-western-central China and Japan.

In this research, we aimed to study the genetic variation and phylogeographic pattern of Ligularia tongolensis, a perennial herb endemic to the Hengduan Mountains region of China. We sequenced two chloroplast DNA (cpDNA) intergenic spacers (trnQ-5'rps16, trnL-rpl32) in 140 individuals from 14 populations of three groups (Jinshajiang vs. Yalongjiang vs. Wumeng) within this species range. High levels of haplotype diversity (Hd = 0.814) and total genetic diversity (Ht = 0.862) were detected at the species level, based on a total of 12 haplotypes identified. Low levels of intrapopulation diversity (Hs = 0.349), high levels of genetic divergence (Gst = 0.595, Nst = 0.614, Fst = 0.597), and the absence of isolation by distance tests were also found in L. tongolensis. Furthermore, H2 and H5, the dominant haplotypes that located at internal nodes and deviated from extinct ancestral haplotype in the network, were found to be shared between Jinshajiang and Yalongjiang groups. These results indicate that past fragmentation may be the important factor responsible for the present phylogeographical pattern of L. tongolensis. Meanwhile, the locations occupied by each group might have served as independent refugia for L. tongolensis during the Quaternary glaciation. Unimodal mismatch distribution and star-like genealogies indicated this species underwent past demographic expansion events, with expansion ages of 274 ka BP.

The effect of (Li,Ce) substitution for A-site on the properties of [(Na 0.52 K 0.42 Li 0.06 )Bi] 0.5 Bi 2 (Nb 1.88 Sb 0.06 Ta 0.06 )O 9 -based ceramics was investigated. The piezoelectric activity of [(Na 0.52 K 0.42 Li 0.06 )Bi] 0.5 Bi 2 (Nb 1.88 Sb 0.06 Ta 0.06 )O 9 -based ceramics is significantly improved by the modification of lithium and cerium. The Curie temperature (T C ) gradually decreases from 625 to 605 °C with increasing the (Li,Ce) modification. The piezoelectric coefficient d 33 of the [(Na 0.52 K 0.42 Li 0.06 )Bi] 0.44 (Li,-Ce) 0.03 [] 0.03 Bi 2 (Nb 1.88 Sb 0.06 Ta 0.06 )O 9 ceramic was found to be 28 pC/N, the highest value among the [(Na 0.52 K 0.42 Li 0.06 )-Bi] 0.5 Bi 2 (Nb 1.88 Sb 0.06 Ta 0.06 )O 9 -based ceramics, also almost 50% higher than the reported d 33 values of other Bismuth layer-structured ferroelectric (BLSF) systems (~5-19 pC/N). The planar coupling factor k p and k t were found to be 7.0 and 28.0%, together with the high T C (~610 °C) and stable piezoelectric properties, demonstrating that the (Li,Ce) modified [(Na 0.52 K 0.42 Li 0.06 )Bi] 0.5 Bi 2 (Nb 1.88 Sb 0.06 Ta 0.06 )O 9 -based material a promising candidate for high temperature applications.

The effect of K content on the properties of LiCe co-substituted (Na 1―x K x ) 0.5 Bi 4.5 Ti 4 O 15 -based ceramics was investigated. The Curie temperature (T C ) gradually decreases from 641 to 551 °C with increasing the K content. The piezoelectric coefficient d 33 , thickness coupling factor k t , and mechanical quality factor Q of (Na 0.5 Bi 0.5 ) 0.80 (Li 0.5 Ce 0.5 ) 0.10 [] 0.10 Bi 4 Ti 4 O 15 (x = 0.00) ceramic were found to be 28 pC/N, 25%, and 2693, respectively, together with the high T C (∼641 °C) and stable piezoelectric properties, demonstrating that the (LiCe) modified Na 0.5 Bi 4.5 Ti 4 O 15 -based material a promising candidate for high temperature applications.

BACKGROUND A G > C polymorphism (rs2910164) which is located in the sequence of miR-146a precursor, results in a change from a G:U pair to a C:U mismatch in its stem region. To explore whether rs2910164 plays any role in prostate cancer (CaP), we analyzed the association between miR-146a polymorphism and risk of CaP and the expression of miR-146a with different genotypes in CaP tissues in southern Chinese Han population. MATERIALS AND METHODS Two hundred fifty-one CaP and 280 control subjects were included in the cancer association study, and 15 CaP tissue samples were used to test the expression of the miRNA precursors by real-time quantitative reverse transcription PCR. RESULTS We found that subjects carrying CC homozygotes had a 0.65-fold reduced risk (95% CI = 0.43–0.99) than those carrying GG/GC genotypes (P = 0.03), and the C allele displayed a lower prevalence of CaP compared with the G allele (OR = 0.73, 95% CI = 0.57–0.94, P = 0.01). Moreover, hsa-miR-146a quantification showed that homozygous carriers of the C-variant had significantly decreased miRNA levels compared to the carriers of the GG/GC genotype. CONCLUSIONS The natural genetic variation in pre-miR-146a affects the amount of mature miR-146a, contributes to the genetic predisposition to CaP. Prostate 70: 467–472, 2010. © 2009 Wiley-Liss, Inc.

(Na0.48–xK0.48–xLi0.04Srx)Nb0.89Ta0.05Sb0.06O3 (abbreviated as NKLSrx NST) lead-free ceramics are fabricated by conventional solid state reaction. The material with perovskite structure contains both tetragonal and orthorhombic phases at room temperature when x ≤ 0.02, and it changes into cubic phase gradually as x increases. A second phase KSr2Nb5O15 begins to appear at x = 0.03 and becomes obvious with increasing Sr content. Dielectric studies show that the Sr2+ modification lowers the Curie temperature and induces the diffuseness of cubic–tetragonal phase transition. The addition of Sr2+ improves the density and piezoelectric properties of NKLNST. The ceramic modified with 0.008 mol SrO shows the optimum piezoelectric properties (d33 = 278 pC/N, kp = 0.504, tan δ = 0.025). Degradation of kp is found after the first thermal cycling due to the tetragonal–orthorhombic phase transition near room temperature. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The microstructure, and dielectric and piezoelectric properties of the CeO2-modified potassium bismuth titanate K0.5Bi4.5Ti4O15 (KBT) piezoelectric ceramics were investigated. X-ray diffraction analysis revealed that the cerium-modified KBT ceramics have a pure four-layer Aurivillius-type structure. The piezoelectric properties of KBT ceramics were significantly enhanced and the dielectric loss decreased by cerium doping. The Curie temperature Tc and piezoelectric coefficient d33 for the KBT ceramics with 0.50 wt% cerium modification were found to be 550°C and 28 pC/N, respectively. The Curie temperature was found to decrease gradually from 555° to 541°C with cerium modification up to 1.00 wt%. Dielectric and annealing spectroscopy showed that the materials possess stable piezoelectric properties.

An Aurivillius phase bismuth layer-structured compound potassium bismuth titanate is synthesized using conventional solid-state processing. It was found that the range of sintering temperature for the potassium bismuth titanate is very narrow. Phase analysis was performed by X-ray diffraction, and microstructural morphology was assessed by scanning electron microscopy. The Curie temperature TC, piezoelectric coefficient d33, and mechanical quality factor Qm (kp mode) of the dense potassium bismuth titanate were found to be 555°C, 21.2 pC/N, and 1602, respectively. Dielectric spectroscopy showed that potassium bismuth titanate possesses stable high-temperature dielectric properties.

The effect on microstructure and electrical properties of (Co, Nb)-doped SnO2 varistors upon the addition of Pr2O3 was investigated by scanning electron microscopy and by determining I–V, ɛ–f, and R–f relations. The threshold electric field of the SnO2-based varistors increased significantly from 850 to 2280 V/mm, and the relative dielectric constants of the SnO2-based varistors decreased greatly from 784 to 280 as Pr2O3 concentration was increased up to 0.3 mol%. The significant decrease of the SnO2 grain size, from 4.50 to 1.76 μm with increasing Pr2O3 concentration over the range of 0–0.3 mol%, is the origin for the increase in the threshold voltage and decrease of the dielectric constants. The grain size reduction is attributed to the segregation of Pr2O3 at grain boundaries hindering the SnO2 grains from conglomerating into large particles. Varistors were found to have a superhigh threshold voltage and a comparatively large nonlinear coefficient α. For 0.15 mol% Pr2O3-doped sample, threshold electric field and nonlinear coefficient α were measured to be 1540 V/mm and 61, and for 0.3 mol% Pr2O3-doped sample, V and α were 2150 V/mm and 42, respectively. Superhigh threshold voltage and large nonlinear coefficient α qualify the Pr-doped SnO2 varistor as an excellent candidate for a high voltage protection system.

The piezoelectric, dielectric, and electromechanical properties of the (KCe) co-substituted calcium bismuth niobate (CaBi2Nb2O9, CBN) were investigated. The piezoelectric activities of CBN ceramics were significantly enhanced and the dielectric loss tan δ decreased by (KCe) substitution. The Ca0.9(KCe)0.05Bi2Nb2O9 ceramics possess the optimal piezoelectric properties, and the piezoelectric coefficient (d33), Curie temperature (TC), and electromechanical coupling factors (kp and kt) were found to be 16 pC/N, 868 °C, 8.6%, and 23.8%, respectively. The excellent dielectric and electromechanical spectra, together with the high piezoelectric activities and ultrahigh Curie temperature, make CBN ceramics promising candidates for high temperature piezoelectric applications. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The piezoelectric properties of the cobalt-modified sodium bismuth titanate (Na0.5Bi4.5Ti4O15, NBT) piezoelectric ceramics were investigated. The piezoelectric properties of NBT ceramics were significantly enhanced by cobalt modification. The Curie temperature TC and piezoelectric constant d33 for the 0.3 wt% cobalt-modified NBT ceramics (NBT-C3) were found to be 663 °C and 30 pC/N, respectively. Thermal annealing studies presented that the cobalt-modified NBT ceramics possess stable piezoelectric properties, demonstrating that the cobalt-modified NBT-based ceramics are promising candidates for high temperature piezoelectric applications. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The cerium modified sodium bismuth titanate (Na0.5Bi4.5Ti4O15, NBT) piezoelectric ceramics have been prepared by using the conventional mixed oxide method. X-ray diffraction analysis revealed that the cerium modified NBT ceramics have a pure four-layer Aurivillius phase structure. The piezoelectric activity of NBT ceramics was found significantly improved by the modification of cerium. The Curie temperature Tc, and piezoelectric coefficient d33 for the NBT ceramics with 0.50 wt% cerium modification were found to be 655 °C, and 28 pC/N respectively. The Curie temperature gradually decreased from 668 °C to 653 °C with the increase of cerium modification. The dielectric spectroscopy showed that the samples possess stable piezoelectric properties, demonstrating practical potential that for high temperature applications. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

A new langasite type single crystal Ca 3 NbGa 3 Si 2 O 14 (CNGS) was grown by Czochralski (CZ) method. The structure of CNGS crystal was determined by X-ray powder diffraction, the lattice parameters were a =0.8087 ± 0.0001 nm, c =0.4974 ± 0.0002 nm, V =0.2817 ± 0.0002 nm 3 ; The congruency of CNGS was examined by measuring the chemical composition of the grown crystal by quantitative X-ray fluorescent (XRF) analysis. The melting point of CNGS crystal was measured by using the differential scanning calorimetry (DSC). Dielectric properties of (1 1 0) wafer plate were studied in the temperature range from 298.15 to 873.15 K; the frequency dependence of dielectric loss in the frequency range 10 Hz–13 MHz was measured.