污水厂尾水的人工湿地处理工艺及植物筛选

利用土壤作为水平潜流人工湿地的填料,处理某生活污水处理厂的尾水。结果表明该潜流湿地对COD、NH3 N、TN和TP有很好的去除效果,其平均去除率分别达到78．7％、99．3％、67．2％和96．4％。移植土著植物,通过试验筛选出对N去除效果比较好的品种为菖蒲、马兰和石菖蒲,对P去除效果比较好的三种植物为马兰、萱草和菖蒲。     

苯系化合物降解的微生物筛选及其特性初探

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。     

透明质酸高产菌株选育研究

从新鲜水牛鼻粘膜分离筛选得到15株菌株,经生化反应鉴定其中5株为透明质酸(HA)产生菌。对产量最高的菌株B发酵液精提物进行红外吸收光谱(IR)、核磁共振(13CNMR)、紫外吸收光谱(UV)分析,证明其发酵液精提物确为HA。菌株B经超声波/紫外线复合诱变处理后,HA产量由0.793 g.L-1提高到1.46 g.L-1。     

新型化学木浆封闭筛选洗涤流程、设备及操作控制

双辊挤压型洗浆机因其洗涤因子小、洗涤效率高而在木浆生产过程中被广泛采用。控制好封闭热筛选实际运行中的压力筛压差,对于防止筛板糊堵和排渣阀堵塞非常重要,流量因子的正确设定和调整在串级控制运行模式下是封闭热筛选正常运行的关键。     

小肠肠炎耶尔森菌天然抑菌剂的快速筛选

在96孔板中培养后利用酶标仪测定了天然酚类物质香兰素、异丁香酚、丁香酚、麝香草酚、愈创木酚存在下小肠肠炎耶尔森菌的光密度(OD)值,并绘制了相应的OD-t生长曲线,该测定方法具有快速、高通量、准确的优点。受试菌生长曲线表明:一定浓度的天然酚类物质对受试菌种有不同程度的抑制作用,其大小顺序为:异丁香酚>麝香草酚>丁香酚>香兰素>愈创木酚,对受试菌的最低抑菌浓度分别为660、1180、1280、1380、2040mg/L。     

Screener3D:a gaseous time projection chamber for ultra-low radioactive material screening

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.     

一阶及二阶调频加网频谱特性及频率传递分析

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.     

基于可变模糊聚类迭代模型的溃坝生命损失预测

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。     

Beck Depression Inventory-Fast Screen (BDI-FS): an efficient tool for depression screening in patients with end-stage renal disease

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.     

A dual gradient assay for the parametric analysis of cell-surface interactions

Cellular response to microgrooves is addressed using a new assay format, comprising orthogonal gradients of continuously varied groove pitch and depth. Dual layer etch masks are created using a combination of micropatterning and plasma polymer deposition. A silicon substrate with a constant groove width of 8 μm and with ridge width increasing from 8 μm in 0.5 μm steps across 10 mm is fabricated by photolithography. A plasma-polymerized hexane film which is 120 nm thick at one end of these grooves, and 10 nm at the other, is deposited under a diffusion mask. Reactive etching of the patterned sample transfers a gradient of groove pitch and groove depth into the silicon substrate. A silicon master with a gradient of groove depth spanning more than two orders of magnitude (less than 10 nm to over 1000 nm) is used to create an injection molding inlay for mass replication of the screening topography. Polycarbonate replicas are molded for use in cell culture studies, and the functionality of the topography as a high-throughput screening platform is investigated. The response of MDCK, h-TERT fibroblasts, and LE2 endothelial cells is examined, in terms of attachment and morphological response to the variation in topographical cues, with the aim of pinpointing the optimal combination of groove pitch and depth to elicit a tailored response from each cell type. When the range of topographical features screened on a single substrate is considered, this new assay represents a significant step forward in the parametric design and analysis of topographical cues at the biomaterial interface.