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PURPOSE: Treatment of spinal anesthesia-induced hypotension in patients with severe preeclampsia assumes special concern as hypotension may further reduce placental perfusion. Phenylephrine is still the first-line vasopressor for treating spinal anesthesia-induced hypotension. However, the optimal dose of phenylephrine used as intravenous (IV) boluses in patients with severe preeclampsia has not been clearly determined. We aim to calculate the 90% effective dose (ED90) of phenylephrine as IV boluses for treating spinal anesthesia-induced hypotension in patients with severe preeclampsia undergoing cesarean delivery. PATIENTS AND METHODS: Forty patients with severe preeclampsia were enrolled in this prospective sequential allocation dose-finding trial. Using the biased coin up-and-down (BCUD) method, all patients in our study received an IV bolus phenylephrine of either 40, 50, 60, 70, or 80 µg when the mean arterial pressure (MAP) decreased to less than 80% of the baseline level and the ED90 was determined. The primary outcome was the success of the assigned phenylephrine bolus to maintain the MAP at or above 80% of baseline value between the induction of spinal anesthesia and delivery of the fetus. Secondary outcomes included hypertension, nausea, vomiting, bradycardia, upper sensory level of anesthesia, umbilical blood gases, and Apgar score. Estimating of the ED90 with 95% confidence interval (CI) was achieved by isotonic regression method. RESULTS: The ED90 of phenylephrine was estimated as 62.00 µg (95% CI=50.00-67.40 µg) using the isotonic regression method. No patients enrolled in our study experienced bradycardia and those patients who developed hypertension were all observed at the dose level 70 µg. CONCLUSION: For clinical practice, we recommend that phenylephrine 60 µg may be both effective and safe for treatment of spinal anesthesia-induced hypotension in severe preeclampsia during cesarean delivery.

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Spectrum denoising is an important part of spectrum detection. As we know, spectral signal is susceptible to thermal noise, mechanical vibration on site and random noise, etc. However, online monitoring systems require to reduce the impact of parameter selection caused by human operation on denoising, so a method based on singular value decomposition is proposed to denoise spectrum signal. An improved effective singular value selection method is also proposed. First, the author specify the maximum peak of the difference spectrum of singular value for the lower bound which named θ1, using the integrated information of singular value and its difference spectrum to select the upper bound, which is called θ2. The interval θ1～θ2 is defined as a fuzzy area. Then, the membership is obtained with Fuzzy C-means clusting and corresponding weight coefficients to the singular values in the fuzzy area are given. Finally, the proposed method is used to denoise UV spectrum signal with different signal to noise ratio. The signal to noise ratio, root mean square error, normalied correlation coefficient and smoothness radio are used to evaluate the result of denoising. The result shows that: based on data-driven, the proposed method has a good denoising effect, which can effectively restore the original signal.

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As the basis of accurate diagnosis, fault early-warning of gas insulation switchgear (GIS) focuses on the time-effectiveness and the applicability. It would be significant to research the method of unified early-warning for partial discharge (PD) and overheated faults in GIS. In the present paper, SO2 is proposed as the common and typical by-product. The unified monitoring could be achieved through ultraviolet spectroscopy (UV) detection of SO2. The derivative method and Savitzky-Golay filtering are employed for baseline correction and smoothing. The wavelength range of 290-310 nm is selected for quantitative detection of SO2. Through UV method, the spectral interference of SF6 and other complex by-products, e.g., SOF2 and SOF2, can be avoided and the features of trace SO2 in GIS can be extracted. The detection system is featured by compacted structure, low maintenance and satisfactory suitability in filed surveillance. By conducting SF6 decomposition experiments, including two types of PD faults and the overheated faults between 200-400 degrees C, the feasibility of proposed UV method has been verified. Fourier transform infrared spectroscopy and gas chromatography methods can be used for subsequent fault diagnosis. The different decomposition features in two kinds of faults are confirmed and the diagnosis strategy has been briefly analyzed. The main by-products under PD are SOF2 and SO2F2. The generated SO2 is significantly less than SOF2. More carbonous by-products will be generated when PD involves epoxy. By contrast, when the material of heater is stainless steel, SF6 decomposes at about 300 "C and the main by-products in overheated faults are SO2 and SO2F2. When heated over 350 degrees C, SO2 is generated much faster. SOz content stably increases when the GIS fault lasts. The faults types could be preliminarily identified based on the generation features of SO2.

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By detecting the stable by-products of SF6 through ultraviolet spectroscopy, the present paper achieved the rapid detection of the GIS partial discharge fault. First derivative and the S-G filter were used for the spectral denoising and smoothing. The discharge experiment was used for validating feature selection. Principal component regression was used for the analysis of the concentration of SO2. The concentration of SO2 was used for fuzzy judge. By selecting the appropriate wavelength range (295~305 nm), ultraviolet spectrum can identify SO2 from the complex by-products of SF6. In this paper, firstly, the author reviewed the decomposition mechanism of SF6 under partial discharge, and then verified the rationality of detecting partial discharge by UV, and ultimately achieved the rapid detection of GIS partial discharge and fuzzy judgment of discharge time.

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OBJECTIVE: To evaluate the changes in dimensional accuracy of dental gypsum casts after immersion in stable chlorine dioxide (SCD) disinfectant solution. METHODS: Each of 90 specimens was made of type III,type IV and type V dental stone, respectively,which were further divided into 9 groups (n=10). The gypsum casts were immersed in 3.71,7.41 and 11.12 mmol/L SCD disinfectant solution for 5, 10 and 15 min, respectively. The dimensional accuracy of dental gypsum casts were measured with outside diameter in micrometer before and after immersion. The data were analyzed using analysis of variance (ANVOA) at 95% confidence level. RESULT: There were no significant changes in dimensional accuracy of all dental gypsum casts treated by same concentration of SCD solution for 5, 10 and 15 min. And the dimensional accuracy of all dental gypsum casts treated with different concentrations of SCD for the same duration did not change. CONCLUSION: SCD disinfectant solution has no impact on dimensional stability of dental gypsum casts.

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The title compound, C(10)H(12)N(2)O, is approximately planar, the r.m.s. deviation of the non-H atoms from the mean plane being 0.099 Å.

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OBJECTIVE: Purpose of the study was to investigate the content of Nickel (Ni) and Chromium (Cr) ion in gingival tissue and blood, and to discuss the reason of gray line in gingival after wearing non-noble Porcelain-Fused-to-Metal crown. METHODS: 38 rabbits were selected as experimental animals which were divided into three groups: control group, group 1 (3 months) and group 2 (6 months). The content of Ni and Cr ion in gingival tissue and blood was detected by atomic absorption spectrometer. RESULTS: The amount of Ni and Cr in group 2 was significantly higher than that in other groups (P < 0.05) . There was no difference between group 1 and control group (P > 0.05) . CONCLUSION: The reason of gingival colouration might be the electrochemical corrosion. The metal ion was released in gingival tissue and blood.

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OBJECTIVE: To study the expression of PCNA/bcl-2 protein in gray and normal gingival tissue, and to investigate the biological effect of procelain-fused-to-metals (PFM). METHODS: Gray gingival tissue animal model was established by PFM prosthesis and immunohistochemistry S-P method was used to detect the PCNA/bcl-2 protein expression in gingival tissue after 3 months, 6 months in PFM groups and control group. RESULTS: The expression of PCNA had significant difference between the 3th month group and the control group (P < 0.05); no significant difference was found between the 6th month group and the control group (P > 0.05). The expression of bcl-2 had no significant difference between the 6th month group and the control group (P > 0.05). CONCLUSION: There were a correlation between the expression of PCNA and inflammation of the gray gingival tissue; The expression of PCNA and bcl-2 protein does not indicate that gray gingival tissue had dysplasia change.

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