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991.
Taomin Huang Xiaoxia Li Shuang Hu Bo Zhao Ping Chen Xiao Liu Deyong Ye Nengneng Cheng 《Lipids》2014,49(10):1071-1079
A novel sensitive high‐performance liquid chromatography‐fluorescence detection (HPLC‐FLD) method was developed for real‐time monitoring of relative sphingomyelin synthase (SMS) activity based on the measurement of a fluorescent ceramide (Cer) analog and its metabolite, a fluorescent sphingomyelin (CerP Cho) analog, in plasma. Analyses were conducted using HPLC‐FLD following a protein precipitation procedure. The chromatographic separations were carried out on an Agilent C18 RP column (150 × 4.6 mm, 5 μm) based on a methanol—0.1 % trifluoroacetic acid aqueous solution (88:12, by vol) elution at a flow‐rate of 1 mL/min. The limit of quantification in plasma was 0.05 μM for both the fluorescent Cer analog and its metabolite. Significant differences in the fluorescent Cer analog and its metabolite concentration ratio at 5 min were found between vehicle control group and three D2 (a novel SMS inhibitor) dose groups (P < 0.05). Dose‐dependent effects (D2 doses: 0, 2.5, 5, 10 mg/kg) were observed. Our method could be used to detect relative SMS activity in biochemical assays and to screen potential SMS inhibitors in vivo. D2 was found to be a potent SMS inhibitor in vivo, and may have a potential antiatherosclerotic effect, which is under further study. D609 was also selected as another model SMS inhibitor to validate our newly developed method. 相似文献
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993.
苯系化合物降解的微生物筛选及其特性初探 总被引:2,自引:1,他引:1
为选育高效降解苯系物的菌株,该研究选用污水处理厂处理废水的活性污泥作为菌源,分别以甲苯、乙苯、二甲苯作为底物,在好氧条件下,驯化、筛选和分离出了能以上述化合物作为生长的唯一碳源和能源的微生物菌株,并对其进行了初步的鉴定,分别是假单细胞菌属(Pseudomonas sp.)、芽孢杆菌属(Bacillus sp.)、红球菌属(Rhodococcus sp.)等。结果表明,对甲苯的降解率可以达到95%~98%,对乙苯的降解率为80%~88%,对二甲苯的降解率维持在70%~80%之间。进一步研究表明混合菌的最佳生长条件为培养温度30℃,培养时间48 h,接种量10%,摇床转速180 r/min,降解甲苯、乙苯时的pH为7~9,降解二甲苯时的pH为4或10。 相似文献
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997.
Hai-Yan Du Cheng-Bo Du Karl Giboni Ke Han Sheng-Ming He Li-Qiang Liu Yue Meng Shao-Bo Wang Tao Zhang Li Zhao Ji-Fang Zhou 《核技术(英文版)》2021,32(12):103-115
In experiments searching for rare signals,back-ground events from the detector itself are some of the major factors limiting search sensitivity.Screening for ultra-low radioactive detector materials is becoming ever more essential.We propose to develop a gaseous time projection chamber(TPC)with a Micromegas readout for radio screening.The TPC records three-dimensional tra-jectories of charged particles emitted from a flat sample placed in the active volume of the detector.The detector can distinguish the origin of an event and identify the particle types with information from trajectories,which significantly increases the screening sensitivity.For a particles from the sample surface,we observe that our proposed detector can reach a sensitivity higher than 100 p Bq m-2 within two days. 相似文献
998.
为了获取不同类型调频加网对图像细节的传递能力和特性,应用快速傅立叶变换(FFT)分别对Photoshop的误差扩散法一阶调频及KODAK Stacca-to二阶调频加网图像进行了频谱分析.分析结果表明:Staccato二阶调频加网具有较为对称均匀的频谱分布;在对不同频率空间正弦波的传递方面,两种调频加网的传递能力接近. 相似文献
999.
基于可变模糊聚类迭代模型的溃坝生命损失预测 总被引:1,自引:0,他引:1
针对我国溃坝相关资料缺乏、数据均匀连续性较差的现状,将可变模糊集理论引入到溃坝生命损失预测中,建立基于可变模糊聚类(VFC)循环迭代模型的人口死亡率预测模型。采用相邻模糊标度法确定指标权重,运用模型得到最优相对隶属度矩阵和最优聚类中心矩阵,结合欧氏距离,对样本进行二次筛选,再运用指数加权平均法,计算得到待估样本人口死亡率估计值。实例验算证明,该模型符合我国现状,具有一定的实用性和较高的精度。 相似文献
1000.
Neitzer A Sun S Doss S Moran J Schiller B 《Hemodialysis international. International Symposium on Home Hemodialysis》2012,16(2):207-213
Depression is common in patients suffering from end-stage renal disease (ESRD). Various screening tools for depression in ESRD patients are available. This study aimed to validate the Beck Depression Inventory-Fast Screen (BDI-FS) with the Beck Depression Inventory-II (BDI-II) as depression screening tool in conventional hemodialysis (CHD) patients. One hundred sixty two CHD patients were studied with both screening questionnaires. We used the Pearson Correlation Coefficient to measure the agreement between BDI-II and BDI-FS scores from 134 patients who responded to both questionnaires. Receiver operating characteristics curve and area under the curve were constructed to determine a valid BDI-FS cutoff score to identify ESRD patients at risk for depression. BDI-II and BDI-FS scores strongly correlated (Pearson r = 0.85, p < 0.0001). At a BDI-II cutoff ≥16, receiver operating characteristics showed the best balance between sensitivity and specificity for the BDI-FS cutoff value of ≥4 with a sensitivity of 97.2% (95% confidence interval [CI]: 85.5%, 99.9%) and a specificity of 91.8% (95% CI: 84.5%, 96.4%). When applying the above cutoff scores, prevalence of depressive symptoms in all completed questionnaires was found to be 28.7% (BDI-II) and 30.1% (BDI-FS), respectively. The BDI-FS was found to be an efficient and effective tool for depression screening in ESRD patients which can be easily implemented in routine dialysis care. 相似文献