Abstract Yttrium aluminium borate crystals have excellent physical and chemical properties. In this paper, the electron paramagnetic resonance g factors g ∥, g ⊥ of Yb3+ and hyperfine structure constants A ∥, A ⊥ of 171Yb3+ and 173Yb3+ isotopes in YAl3(BO3)4 crystal are calculated from the perturbation formulas. The crystal field parameters are obtained from the superposition model and the crystal structure data. The electron paramagnetic resonance parameters for trigonal Yb3+ centers in YAl3(BO3)4 are reasonably explained by considering the defect structures of doped Yb3+ centers. In the calculation, we also find that Yb3+ ion does not exactly reside in Y3+ site, but suffers an angle distortion ∆θ(≈ 3.98o) with C3 axis. The results are discussed.

OBJECTIVES: Osteoporotic vertebral compression fractures (OVCFs) affect the elderly population, especially postmenopausal women. Percutaneous kyphoplasty is designed to treat painful vertebral compression fractures for which conservative therapy has been unsuccessful. High-viscosity cement can be injected by either a hydraulic pressure delivery system (HPDS) or a balloon tamp system (BTS). Therefore, the purpose of this study was to compare the safety and clinical outcomes of these two systems. METHODS: A random, multicenter, prospective study was performed. Clinical and radiological assessments were carried out, including assessments of general surgery information, visual analog scale, quality of life, cement leakage, and height and angle restoration. RESULTS: Using either the HPDS or BTS to inject high-viscosity cement effectively relieved pain and improved the patients’ quality of life immediately, and these effects lasted at least two years. The HPDS using high-viscosity cement reduced cost, surgery time, and radiation exposure and showed similar clinical results to those of the BTS. In addition, the leakage rate and the incidence of adjacent vertebral fractures after the HPDS treatment were reduced compared with those after treatment using the classic vertebroplasty devices. However, the BTS had better height and angle restoration abilities. CONCLUSIONS: The percutaneous HPDS with high-viscosity cement has similar clinical outcomes to those of traditional procedures in the treatment of vertebral fractures in the elderly. The HPDS with high-viscosity cement is better than the BTS in the treatment of mild and moderate OVCFs and could be an alternative method for the treatment of severe OVCFs.

Abstract The spin Hamiltonian parameters (SHPs) (g factors and zero-field splittings (ZFSs) D and E) and the local structure for Cr3+ in K2PdCl4 single crystal are theoretically investigated from the perturbation calculations of the SHPs for an orthorhombically distorted octahedral 3d3 cluster. The impurity Cr3+ is found not to occupy the conventional square planar Pd2+ site but to locate at the octahedral K+ site, associated with the relative axial compression ratio ρ( ≈ 11.1%) and the perpendicular bond length variation ratio τ( ≈ 11.7%). The impurity centre exhibits much smaller axial compression distortion and much larger perpendicular orthorhombic distortion than the host K+ site in K2PdCl4 ρ H ≈ 18.6% and τ H ≈ 0) and hence a more regular ligand octahedron, corresponding to the very small ZFSs. The contributions to g-shifts Δ g C T from the CT mechanism are opposite in sign and twenty-one times larger in magnitude compared with Δ g C F from the CF mechanism. For the ZFSs, the CT contributions DCT and ECT are opposite in sign and almost the same in magnitude with respect to the corresponding DCF and ECF.

A toxoplasmose é uma zoonose global causada pelo Toxoplasma gondii, o qual pode infectar animais de sangue quente e seres humanos. Este estudo foi realizado com o objetivo de investigar a soroprevalência em cavalos para T. gondii, na região de Xinjiang, no Noroeste da China. Em 2011, foram recolhidas 637 amostras de sangue em sete distritos da Prefeitura Autônoma de Changji Hui do Xinjiang, as quais foram testadas para a presença de anticorpos, utilizando-se o teste de aglutinação modificado (MAT). Foram estimados fatores de risco relacionados com a soroprevalência (idade, sexo e distrito), através de uma análise de regressão logística multivariada. Um total de 200 equinos (31,4%, 95% IC 27,79 – 35,00) foi positivo para T. gondii. Idade, sexo e região estudada não apresentaram associação com a soroprevalência (p>0,05) na análise de regressão logística. Os resultados revelam que a infecção por T. gondii tem uma prevalência generalizada em todo o território de Xinjiang, no Noroeste da China, constituindo uma séria ameaça à saúde de animais e de humanos. Consequentemente, propõe-se que sejam adotadas medidas reforçadas para o controle e prevenção da infecção de cavalos por T. gondii, no Xinjiang, Noroeste da China.

Toxoplasmosis is a worldwide zoonosis caused by Toxoplasma gondii, which can infect warm-blooded animals and humans. The present study was performed to investigate the seroprevalence of T. gondii in horses in Xinjiang, northwestern China. A total of 637 blood samples were collected from seven regions in Changji Hui Autonomous Prefecture, Xinjiang in 2011 and assayed for T. gondiiantibodies using the modified agglutination test (MAT). Risk factors (age, gender, and region) related to seroprevalence were determined by a multivariate logistic regression analysis. A total of 200 horses (31.4%, 95% CI 27.79–35.00) were seropositive for T. gondii. Age, gender, and region present no association with seroprevalence (p>0.05) in the logistic regression analysis. The results indicated that T. gondii is widely prevalent in horses in Xinjiang, northwestern China, representing a serious threat to animal and human health. Therefore, more careful measures should be performed to control and prevent T. gondii infection in horses from Xinjiang, northwestern China.

Melt blowing is commonly used to convert polymer resin directly into nonwoven fabrics of superfine fibers. Further decrease of the fiber diameter will improve the filtration and adsorption properties remarkably and thus has been appealing to the researchers. Besides the dual slot die, the annular die is utilized to manufacture superfine fibers in the melt blowing process as well. In the dual slot die, the high velocity air flow from both sides of the polymer melt. However, the air encircles the polymer melt entirely in the annular die, which is in favor of the polymer drawing and thus manufacture of nanofibers. In this paper, the air flow field model of the annular die is established and solved numerically. The polymer drawing with the melt blowing annular die is modeled and simulated by introducing the simulation results of the air flow field. The predicted fiber diameters coincide with the experimental data. Effects of the polymer flow rate and initial air velocity on the fiber diameter are also explored. The results show good perspective of using melt blowing technology to manufacture nanofibers materials because melt blowing has a higher output than electrospinning.