Crystal Structure and Ferroelectric Evidence of BaZnSi3 O8 , a Low-Permittivity Microwave Dielectric Ceramic.

BaZnSi3 O8 ceramic was prepared by the conventional solid-state method and sintered at 1100 °C. XRD and synchrotron Rietveld refinement analyses revealed the BaZnSi3 O8 ceramic presented a monoclinic structure with a space group of P21 /a (No.14), which is reported for the first time. The BaZnSi3 O8 ceramic presented a weak ferroelectricity, which was confirmed by the P-E loop and the 90° nanoscale ferroelectric domain. Although ϵr -T displayed two ϵr abnormal peaks at 400 °C and 460 °C, the Curie temperature (Tc ) was located at 460 °C according to the dielectric loss and Curie-Weiss law. Moreover, the BaZnSi3 O8 ceramic exhibited optimized microwave dielectric properties with ϵr =6.55, Q×f=52400 GHz, and τf =-24.5 ppm/°C. Hence, the BaZnSi3 O8 ceramic in the ternary BaO-ZnO-SiO2 system possessed both weak ferroelectricity and microwave dielectric properties. These results are expected to break the technical barrier of ferroelectric phase shifter applications in microwave and even millimeter-wave frequency bands.

Preoperative and postoperative analgesic techniques in the treatment of patients undergoing transabdominal hysterectomy: a preliminary randomized trial.

BACKGROUND: Although pre-emptive analgesia is commonly used for the management of postoperative pain in developed countries, no defined protocol has been carried out and widely practiced, especially in transabdominal hysterectomy. Keeping this in mind the present study aimed to investigate the effects of multimodal pre-emptive analgesia on pain management, stress response and inflammatory factors of patients undergoing transabdominal hysterectomy to find an optimized way of pre-emptive analgesia. METHODS: One hundred patients undergoing abdominal hysterectomy were randomly divided into four groups (Trial registration: ChiCTR-IPR-15005848). Group P1 was given intravenous flurbiprofen and epidural fentanyl + ketamine before surgery; Group P2 received intravenous flurbiprofen before surgery and epidural fentanyl + ketamine after surgery; Group P3 was given epidural fentanyl + ketamine before surgery and intravenous flurbiprofen after surgery; Patients in Group C received normal saline treatment. RESULTS: Compared with control group, the first time to request additional analgesics after surgery were significantly later (P < 0.05), 24 h dosage of analgesia were significantly less (P < 0.05), VAS score at all time periods after surgery were significantly lower (P < 0.05) in Group P1, P2, or P3. At 12 h or 24 h after surgery, VAS score in Group P1 was significantly lower than that in group P2 or P3 (P < 0.05, P < 0.05). No significant adverse effects were found among the groups (P > 0.05). At 1 or 2 days after surgery, the levels of cortisol, glucose, and IL-6, TNF-α in group P1, P2, and P3 were significantly lower than those in group C (P < 0.05); while, the levels in group P2, P3 were significantly lower than those in group P1 (P < 0.05). CONCLUSION: Multimodal pre-emptive analgesia could significantly lower VAS score, inhibit stress response, and reduce inflammatory response in patients undergoing transabdominal hysterectomy, which can be a rational strategy for pain control in future. TRIAL REGISTRATION: ChiCTR-IPR-15005848 on January 17, 2015.

Effects of chitosan and its derivative added to water on immunological enhancement and disease control.

BACKGROUND: An immune system is a system of biological structures and processes within an organism that protects against diseases by identifying and killing pathogens and tumor cells. Development of novel natural immune enhancers is an urgent issue. METHODS: In experiment 1, Newcastle disease antibody titer, levels of IL-6, IL-10 and IFN-γ, and changes in CD3(+), CD4(+) and CD8(+) cells were analyzed. In experiment 2, diarrhea, respiratory symptoms and mortality of broilers were measured. RESULTS: In experiment 1, the results showed that the immune response, such as Newcastle disease antibody and CD4(+) T cells, would be significantly activated by feeding with chitosan and its derivative during 27 days. In experiment 2, the results demonstrated that diarrhea, respiratory symptoms and the mortality of the commercial medicine treatment group were decreased, with infection days increased. However, the mortality of broilers was significantly decreased, while feed intake and weight gain of the birds were significantly increased in the group treated with chitosan and its derivative as compared with other groups. CONCLUSION: Chitosan and its derivative have strong potential in immune enhancement and disease control, and can be used as a feed additive.

Direct synthesis of ultrafine tetragonal BaTiO3 nanoparticles at room temperature.

A large quantity of ultrafine tetragonal barium titanate (BaTiO3) nanoparticles is directly synthesized at room temperature. The crystalline form and grain size are checked by both X-ray diffraction and transmission electron microscopy. The results revealed that the perovskite nanoparticles as fine as 7 nm have been synthesized. The phase transition of the as-prepared nanoparticles is investigated by the temperature-dependent Raman spectrum and shows the similar tendency to that of bulk BaTiO3 materials. It is confirmed that the nanoparticles have tetragonal phase at room temperature.

Investigation of polarization-induced fading in fiber-optic interferometers with polarizer-based polarization diversity receivers.

A technique is described to eliminate polarization-induced fading in fiber-optic interferometers with two or three polarizers. Modeling and simulation show that two polarizers should be angularly spaced by 90 degrees to alleviate polarization-induced fading. A test system is set up with two 6.5 km fiber coils to link the data. A bistate polarization diversity receiver is tested for reducing polarization-induced fading. The signal is demodulated using a digital phase-generated carrier and the system demonstrates self-noise up to 7.7 microrad/square root Hz (at 1 kHz).