纳米氧化铝对斑马鱼幼鱼早期运动行为的影响

随着纳米技术的迅猛发展,纳米材料的安全性研究具有十分重要的意义。为探讨纳米氧化铝对斑马鱼幼鱼早期运动行为的影响,本研究将受精后6 h(6 hpf)的斑马鱼胚胎随机分成空白对照组(E3培养液)、纳米氧化铝组(12.5、25、50、100μg·mL~(-1))。采用6孔板染毒,每组160颗卵,共8个孔,每孔20颗卵/10 m L试液,染毒液更新周期为1 d。观察急性毒性和运动行为。结果显示,各纳米氧化铝组无明显的急性毒性;运动行为检测发现,25、50、100μg·m L~(-1)纳米氧化铝组受精后6 d幼鱼(6dpf)黑暗状态下的运动速度、运动距离、趋触性程度较空白对照组均显著下降(P0.05);在6 dpf幼鱼对强光刺激的惊恐逃避反射试验中发现,各组幼鱼在光照1 min内运动速度较光照前的黑暗期均明显下降(P0.05),但25μg·mL~(-1)和100μg·mL~(-1)浓度组在光照时速度下降得更慢(P0.05);关闭光源后,各组幼鱼的运动速度都会上升,但25μg·mL~(-1)和100μg·mL~(-1)浓度组在打开光源后速度上升得更慢(P0.05)。上述结果表明,纳米氧化铝可以影响斑马鱼幼鱼早期的运动行为。     

脱氧雪腐镰刀菌烯醇、黄曲霉毒素B_1和玉米赤霉烯酮对秀丽隐杆线虫的联合毒性研究

脱氧雪腐镰刀菌烯醇(DON)、黄曲霉毒素B_1(AFB_1)和玉米赤霉烯酮(ZEN)是最为常见的粮食真菌毒素,易共存于谷物产品和动物饲料中,而目前对其联合毒性的研究较少,且研究结果并不完全一致。为探究DON、AFB_1和ZEN的联合毒性作用,本论文以秀丽隐杆线虫(C.elegans)为模型,分别评估了毒素混合物AFB_1+DON、AFB_1+ZEN、DON+ZEN和AFB_1+DON+ZEN对C.elegans的生长发育(体长)和生殖能力(产卵量)的毒性作用,并用Chou-Talalay模型来判定毒素混合物的相互作用类型。研究表明,AFB_1、DON和ZEN单独染毒C.elegans时,其毒作用强弱为AFB_1ZENDON。联合染毒时,AFB_1+DON对C.elegans产生协同作用,而DON+ZEN则产生拮抗作用;AFB_1+ZEN对体长(24 h)和产卵量的毒作用随着暴露浓度的增加,由弱拮抗变为协同作用,而在毒素暴露48 h后,对线虫的生长发育呈协同作用;AFB_1+DON+ZEN除在EC50-24 h和EC75-24 h时对体长产生明显的毒性增强作用外,其他普遍表现出拮抗作用。由此表明,DON、AFB_1和ZEN对C.elegans的联合毒性作用与剂量和时间相关。     

兴安落叶松林火后对土壤养分和土壤微生物生物量的影响

以大兴安岭兴安落叶松林火后不同强度(重度、中度、轻度)及未火烧区的土壤为研究对象,于火烧结束3年后(2009年)的秋季,采用氯仿熏蒸浸提法测定了不同强度火烧后土壤的微生物生物量碳(C_mic)和微生物生物量氮(N_mic),并研究其与土壤养分因子的关系。结果表明:兴安落叶松林重度火烧区的C_mic显著高于中度、轻度和未火烧区,N_mic在不同强度火烧样地间差异不显著,但在重度火烧区出现最高值。其中重度、中度、轻度和对照的C_mic平均为692.8、499.9、428.8和498.7 mg·kg^-1,而N_mic分别为70.6、55.2、50.9和54.1 mg·kg^-1。土壤含水量、土壤pH值、土壤有机碳对C_mic和N_mic的影响显著,土壤微生物生物量与土壤含水量、pH值、土壤有机碳均呈正相关。研究将为进一步开展火干扰对北方森林土壤碳平衡影响机理研究提供科学依据。     

Species and distribution of rare earth elements in the Baotou section of the Yellow River in China

This paper analyses the contents and species distributions of rare earth elements (REEs) in the water-suspended particulate-sediment system of the Baotou section of the Yellow River, China, with known anthropogenic REE input from industrial discharges. The major forms of REEs were suspended and dissolved in the mainstream and the tributaries of the Baotou section, respectively. The concentrations of the dissolved and suspended REEs had the same trends in the overlying water along the mainstream, which increased from the Seqi section (site A) to the mouth of the Sidaosha River (site D), reaching a maximum value at site D, and tending to decrease thereafter. The contents of REEs in sediment cores showed enrichment with light rare earth elements (LREEs). The bound to carbonates and to Fe–Mn oxides are the major forms of REE in the secondary phase and the REE exhibited LREE enrichment pattern and moderate Eu depletion in suspended particulates and surface sediments. The contents and species distributions of REEs in the water-suspended particulate-sediment system of the Baotou section suggest that the anthropogenic source of REEs from Baotou city have enhanced REE accumulation to the Baotou section. This information is important for predicting possible pollution resulting from anthropogenic REE input into rivers.     

预处理-气浮-氧化沟工艺处理再生纸废水

介绍了预处理-气浮-氧化沟工艺在再生纸废水处理工程中的应用。运行结果表明:该工艺处理效果稳定,耐冲击负荷能力强,进水ρ(COD)、ρ(BOD5)、ρ(SS)分别为1542,654,2254mg/L时,出水分别为77,38,22mg/L,系统出水水质达GB3544-2001《造纸工业水污染物排放标准》。     

污泥龄对高浓度含氮废水亚硝化稳定性的影响研究

为考察污泥龄与高浓度含氮废水亚硝化稳定性之间的关系,采用连续进水、间歇排水SBR工艺,当水力停留时间为0.75 d,污泥停留时间为3 d时,系统亚硝化率约为75%和氨氮降解率约为60%。试验结果证明SRT控制在一定范围内能实现对硝酸菌的"洗出",使亚硝酸菌占据系统中的优势地位,从而保证了系统较高的亚硝化率。     

A stage-structured, Aedes albopictus population model

Aedes albopictus has been the fastest spreading invasive animal species in the world from the mid-1980s until the mid-2000s. In areas it infests, it disrupts native mosquito ecology and can potentially vector up to 21 viruses. To better understand the population dynamics of this species, we created a temperature dependent population model. A stage-structured model was chosen to allow each life-stage to have different temperature dependent mortality and development rates, and each stage was modeled with an ordinary differential equation. Model parameters and distributions were based upon literature values. Initially, a basic model was constructed. This model then had parameters that were forced based upon daily average temperatures. Several criteria were used to evaluate the model, including a comparison to field data from Lubbock, TX. In a stochastic version of the model, a 95% confidence limit contained 70.7% of the field data points. Based upon these results, we feel reasonably confident that we have captured the role of temperature in driving the population dynamics of Ae. albopictus.     

Biosorption of Cr(III) from aqueous solution by freeze-dried activated sludge: Equilibrium,kinetic and thermodynamic studies

Batch biosorption experiments were conducted to remove Cr(III) from aqueous solutions using activated sludge from a sewage treatment plant. An investigation was conducted on the effects of the initial pH, contact time, temperature, and initial Cr(III) concentration in the biosorption process. The results revealed that the activated sludge exhibited the highest Cr(III) uptake capacity (120 mg·g⁻¹) at 45°C, initial pH of 4, and initial Cr(III) concentration of 100 mg·L⁻¹. The biosorption results obtained at various temperatures showed that the biosorption pattern accurately followed the Langmuir model. The calculated thermodynamic parameters, ΔG^o (−0.8– −4.58 kJ·mol⁻¹), ΔH^o (15.6–44.4 kJ·mol⁻¹), and ΔS^o (0.06–0.15 kJ·mol⁻¹·K⁻¹) clearly indicated that the biosorption process was feasible, spontaneous, endothermic, and physical. The pseudo first-order and second-order kinetic models were adopted to describe the experimental data, which revealed that the Cr(III) biosorption process conformed to the second-order rate expression and the biosorption rate constants decreased with increasing Cr(III) concentration. The analysis of the values of biosorption activation energy (E_a = −7 kJ·mol⁻¹) and the intra-particle diffusion model demonstrated that Cr(III) biosorption was film-diffusion-controlled.     

俯采工作面采空区“三带”分布研究

为了防治采空区煤炭自燃,采用热电偶测温和束管气体监测方法对五沟矿1021俯采工作面观测,得到采空区温度及氧浓度的变化情况。通过对温度和氧浓度实测结果的分析,并利用MIN-MAX方法优化,最终确定了采空区"三带"的范围。结合五沟矿煤的自然发火期,可以推算出工作面的临界推进速度,以此有效指导工作面的防灭火工作。