Preparation and characterization of PEG-PEI/Fe3O4 nano-magnetic fluid by co-precipitation method

PEG-PEI/Fe3O4 nano-magnetic fluids with different mass fractions of reactant were prepared by co-precipitation method. Besides particle size analyzer, the methods of XRD, IR, VSM and AFM were adopted to characterize the synthesized samples. Covalent bonding of PEG, PEI and Fe3O4 exhibits superparamagnetism. The TEM photograph shows that the particles are of stable dispersion and little aggregation, with smooth surface, spherical shape and a diameter of about 80 nm, which meets the requirements of nano-materials. When the mass fraction of PEI in reactant is 25%, the particle size, Zeta-potential and pEGFP-CI DNA loading efficiency are all satisfactory. In this case, PEG-PEI/Fe3O4 nano-magnetic fluids can be used as gene vectors or targeted drug carriers.     

修剪高度对沟叶结缕草水分利用效率和耗水量的影响

[目标]研究贵州省黔西南地区,不同修剪留茬高度对沟叶结缕草的水分利用效率和耗水系数的影响.[方法]试验设3、6、9 cm和不修剪4个修剪留茬高度处理,每个处理重复3次,随机排列.每个蒸渗仪为1个试验单元,计采用12个称重式蒸渗仪.根据沟叶结缕草的长势,每月不定期修剪3次.[结果]随着修剪留茬高度由3 cm增至不修剪,沟叶结缕草的耗水量由96.33 mm增至386.60 mm,水分利用效率8月高于7和9月,留茬6 cm的水分利用效率高达0.75 kg/(hm2·mm).[结论]对黔西南地区7～9月的沟叶结缕草的夏季修剪,留茬高度定在6 cm较为理想,既可以节水又能达到美观效果.     

38例老年糖尿病患者烧伤后的护理

总结了38例老年糖尿病患者烧伤的护理.包括清创后采用暴露疗法、抗感染治疗,同时做好血糖的监测和控制,防止并发症的发生.认为老年糖尿病患者烧伤后在做好烧伤护理的同时应积极控制血糖、加强营养支持和健康指导是促进伤口愈合的关键.