凹凸棒土添加对土壤蒸发及裂缝特征的影响

水分是限制干旱与半干旱地区植被恢复和农业发展的最重要因素之一,减少土壤水分无效蒸发损失可提高水分利用效率。凹凸棒土(ATP)作为一种黏土矿物,其亲水性和吸附性对限制土壤蒸发具有重要作用。本研究选取黄土高原干旱与半干旱区3种不同质地的典型土壤(黑垆土、黄绵土、风沙土),设置5种ATP添加量(0%、1%、2%、3%、4%),使用微型蒸发器在自然条件下进行土壤蒸发试验,探究ATP添加对不同土壤蒸发过程和蒸发面裂缝特征的影响。结果表明: 当ATP添加量<3%时,在同一种土壤下累积蒸发量与蒸发损失率随ATP添加量的增加而减小;ATP添加量为3%时,黑垆土、风沙土的累积蒸发量和蒸发损失率均减小,黄绵土的累积蒸发量和蒸发损失率增加;ATP添加量为4%时,黑垆土的累积蒸发量减小、蒸发损失率增加,风沙土的累积蒸发量增加、蒸发损失率减小,黄绵土的累积蒸发量和蒸发损失率均减小。不同土壤平均累积蒸发量表现为:黑垆土>黄绵土>风沙土。在同一种土壤的整个蒸发过程中,施加ATP处理的土壤含水量始终高于对照。累积蒸发量与时间平方根关系的模拟结果表明,蒸发结束时ATP处理下土壤样品可以释放的水量高于对照。添加ATP后黑垆土和黄绵土的裂缝面密度显著增加,风沙土裂缝面密度随ATP添加量的增加而增加,3种土壤的裂缝面密度在ATP添加量为4%时均达到最大值。ATP添加量为3%时可以在最大程度上减少土壤水分无效蒸发。     

Parameters Effects Evaluation of Microbial Strengthening of Sandy Soils in Mixing Experiments Using Taguchi Methodology

The effects of experimental parameters including soil type, curing duration, inoculum size, and biomass and nutrients concentration on soil strengthening due to calcite precipitation by Sporosarcina pasteurii PTCC 1645 were investigated. The laboratory-scale mixing experiments on remolded samples were designed by the Taguchi method. Soil type proved to be the most incorporating factor, followed by curing time and nutrient concentration. The main effect and the interactions of the parameters were presented and the optimal conditions were obtained. This suggests the importance of local conditions including soil type on any future large-scale, in situ application.     

Supramolecular assemblies of zwitterionic nanoliposome-polynucleotide complexes as gene transfer vectors: Nanolipoplex formulation and in vitro characterisation

Synthetic gene transfer vectors based on zwitterionic nanoliposome-DNA assemblies (nanolipoplexes), formed by the mediation of magnesium ions, were prepared by a scalable method without employing volatile solvents, high-shear force treatments or extrusion. The zwitterionic nanolipoplexes (NLP) were formulated with PC (phosphatidylcholine) and DPPC (a natural lung surfactant) incorporating different amounts of cholesterol (CHOL). The resulting structures were characterised in terms of their morphology, size and DNA content. In addition, the toxicity and transfection efficiency of the nanolipoplexes were evaluated in cultured Chinese hamster ovary-K1 (CHO-K1) cells. The effects of the multivalent cation Mg²⁺ on nanoliposome-DNA transfection potency were evaluated. Formulations containing 10% CHOL showed maximum transfection efficiency and the optimum amount of Mg²⁺ ions for transfection with minimum cytotoxicity was ca. 20 mM. The zwitterionic formulations showed significantly less cytotoxicity compared to a commercially available cationic liposome reagent or polyethylenimine (PEI) while they were superior in terms of gene transfer potency. The zwitterionic vectors formulated in this study avoid the use of toxic cationic lipids as well as toxic solvents and may have potential application in gene therapy. The new method will enable scale-up and manufacture of safe and efficacious transfection vehicles required for preclinical and clinical studies. Based on the advantages and superiority of the formulated nanolipoplexes, this method allows for the acceleration of nanolipoplex formulation, enabling the rapid development and evaluation of novel carrier systems for genes and other drugs.     

Development of software for human muscle force estimation

Muscle force estimation (MFE) has become more and more important in exploring principles of pathological movement, studying functions of artificial muscles, making surgery plan for artificial joint replacement, improving the biomechanical effects of treatments and so on. At present, existing software are complex for professionals, so we have developed a new software named as concise MFE (CMFE). CMFE which provides us a platform to analyse muscle force in various actions includes two MFE methods (static optimisation method and electromyographic-based method). Common features between these two methods have been found and used to improve CMFE. A case studying the major muscles of lower limb of a healthy subject walking at normal speed has been presented. The results are well explained from the effect of the motion produced by muscles during movement. The development of this software can improve the accuracy of the motion simulations and can provide a more extensive and deeper insight in to muscle study.     

10种黄酮类抗氧化剂活性差异的理论阐释

借助理论方法,包括结构－活性关系（ＳＡＲ）和最子化学计算阐释了１０种黄酮类抗氧化剂清除自由基活性的痉异。发现ＳＡＲ可以定性地解释抗氧化剂的活性差异。而半经验量子化学方法ＡＭＩ计算的理论参数△ＨＯＦ（抗氧化剂与其抽氢反应产生的自由基的和成热之差）可以对此给出进一步的解释。△ＨＯＦ与抗氧化清除自由基速率常数的对数还有一定相关性,相关系数为－０．７５２３。因此理论方法在解释抗氧化剂的活性差异方面是有效的     

关于数量化I方法的自变量之间交互作用计算

自变量之间存在交互作用时,在应用数量化方法Ｉ时如何计算自变量间的交互作用建立数量化方程．     

我国HEV废旧镍氢电池包中稀贵金属资源化利用环境效益分析

废旧动力电池包中含有丰富的镍、钴、稀土等稀贵金属,其资源化利用是实现混合动力汽车(Hybrid Electrical Vehicle,简称HEV)全生命周期绿色化管理的重要内容之一。随着HEV的不断发展,动力电池包在未来几年将逐渐进入批量报废阶段,其资源化利用的环境效益成为值得关注的问题。鉴于此,以丰田混合动力汽车镍氢电池包为研究对象,利用GREET模型和LIME值法测算出,相比于原生矿开采,单位废旧镍氢电池包中稀贵金属资源化利用所产生的环境效益为1083元;根据报废周期,对我国市场上现存的HEV镍氢电池包的未来报废情况进行预测。结果表明,这些电池包将从2018年开始迎来报废,在2021年达到报废高峰,至2024年基本完成报废;预计其稀贵金属资源化利用的环境效益,可累计达9421万元。提出了加强废旧动力电池回收体系和资源化利用体系建设的政策建议。     

Development and validation of a weight-bearing finite element model for total knee replacement

Total knee arthroplasty (TKA) is a successful procedure for osteoarthritis. However, some patients (19%) do have pain after surgery. A finite element model was developed based on boundary conditions of a knee rig. A 3D-model of an anatomical full leg was generated from magnetic resonance image data and a total knee prosthesis was implanted without patella resurfacing. In the finite element model, a restarting procedure was programmed in order to hold the ground reaction force constant with an adapted quadriceps muscle force during a squat from 20° to 105° of flexion. Knee rig experimental data were used to validate the numerical model in the patellofemoral and femorotibial joint. Furthermore, sensitivity analyses of Young’s modulus of the patella cartilage, posterior cruciate ligament (PCL) stiffness, and patella tendon origin were performed. Pearson’s correlations for retropatellar contact area, pressure, patella flexion, and femorotibial ap-movement were near to 1. Lowest root mean square error for retropatellar pressure, patella flexion, and femorotibial ap-movement were found for the baseline model setup with Young’s modulus of 5 MPa for patella cartilage, a downscaled PCL stiffness of 25% compared to the literature given value and an anatomical origin of the patella tendon. The results of the conducted finite element model are comparable with the experimental results. Therefore, the finite element model developed in this study can be used for further clinical investigations and will help to better understand the clinical aspects after TKA with an unresurfaced patella.     

Investigating the degradation behavior of Cypermethrin (CYP) and Chlorpyrifos (CPP) in peach orchard soils using organic/inorganic amendments

Reducing toxic effects of pesticide residues in agricultural soils through organic amendments is an eco-friendly technique. Cypermethrin (CYP) and Chlorpyrifos (CPP) are widely used pesticides in peach growing orchards in Swat valley of Pakistan. The aim of the current study was to investigate the degradation behavior of CYP and CPP in soil by the application of different combination of organic/inorganic amendments. A total of 36 soil samples were used in the current incubation study which was collected from 4 peach orchards in district Swat, Khyber Pakhtunkhwa (KPK), Pakistan. Different amendments including urea, farm yard manure (FYM) and saprofil were applied alone and in various combinations. The initial concentrations of CYP and CPP in the tested soil was range from 0.94 to 4.8 mg kg⁻¹ and 0.024 to 4.12 to mg kg⁻¹. Soil samples were taken at 5, 15, 30 and 45 days after exposure to different treatments. The extraction of pesticides from soils was done through quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction method. Soils amended with urea, FYM and saprofil individually and in combinations significantly reduced the concentrations of CYP and CPP. However, the concentration of CYP (24.6) and CPP (27.0) in soil showed higher reduction through the application of FYM. While the concentrations of CYP and CPP were declined with the 5, 15, 30 and 45 days intervals, however, reduction at day 30 and 45 was faster for CYP (16.7 to 8.46) than CPP (20.2 to 12.3). At day 5 and 15, the CYP (42.5 to 30.7) was slightly lower than CPP (42.9 to 32.7).The highest half-life value (t ½) of CYP was in control treatment (32 days) and the shortest was soil amended with FYM (18.6 days). While the longest half-life value (t ½) of CPP was maximum in control treatment (42 days) and the minimum was in FYM (22 days). Based on our findings, it was concluded that soil application of FYM is recommended for the degradation of CYP and CPP.     

加纳籽中5-羟基色氨酸的研究进展

5-羟基色氨酸主要存在于豆科植物中,尤其在加纳籽中含量居多。在体内,5-羟基色氨酸是5-羟色胺的前体,是一类重要的神经类药物。对5-羟基色氨酸的生物学作用、检测、生产方面的最新研究进行了概述,并对5-羟基色氨酸资源匮乏的问题提出了建议。