废植物油脂与废聚乙烯塑料共裂解制备燃油研究

研究在高压反应釜中,利用Zr O2/Al2O3/Ti O2多晶泡沫陶瓷催化剂,催化废植物油脂与废聚乙烯塑料共裂解制备燃油。考察了温度、时间、催化剂添加比例、物料质量比等因素对废植物油脂与废聚乙烯塑料共裂解制备燃油的影响。得到适宜的制备条件为反应温度430℃、反应时间40 min、催化剂质量分数15%、物料质量比1∶1,在此条件下,液体产物产率为65.9%。GC-MS分析表明,裂解液体中饱和烃类产物峰面积比例接近100%,其中97.85%为直链烷烃,并初步推断了废植物油脂与废聚乙烯塑料共裂解机理。产物的部分燃料油性能测定结果表明,裂解燃油热值明显高于生物柴油与0号柴油,密度和运动黏度符合0号柴油的标准,冷凝点和冷滤点均优于生物柴油,低温流动性好。     

收获沙棘振动器试验研究

该项研究的核心是研制振动器,通过振动果枝的方式来收获沙棘果实。2003到2004年间,基于我们的试验研究结果显示,沙棘品种＂印度夏季＂通过用频率为40Hz,振幅为15mm,10s为一振动周期的果枝振动器可有效获得果实。利用这个参数的振动可以有效获得90%的果实,且对果枝的损害很小,从果枝上下来的叶片、芽及木枝的碎片也很少。在2003年进行了最原始的研究,2004年测试发现这种方法存在一定缺陷。发电机利用机轴进行来回的旋转运动,利用这个原理进行各种振幅试验,但这对果树各部分会产生大量的压力。用1.5kW的电机可以在车间及没有农业机械的土地上进行试验,但这个过程需要人工看护。最原始的方法效率不高且过程复杂。2005年进行了设备的改进,通过凸轮产生的振动来驱动液压马达。尽管这种方法使用时间还很短,但是它的振动功能还是非常显著的。如果选在最佳采摘季节收获果实,收获的果实品质最佳,同时对果树的伤害也是最小的。如果在每个季节采摘500株或是更少果树的果实,这种振动收获果实的方法是一种最佳选择。     

Effects of high- vs. low-yield environments on selection for increased biomass yield in switchgrass

No information is available on the effects of different biomass yield environments on selection efficiency in switchgrass (Panicum virgatum L.) breeding improvement. This study was conducted to assess the effects of high- and low-biomass yield environments (HYE and LYE, respectively) on recurrent selection for general combining ability (RSGCA) in a lowland population of switchgrass (NL-94). The top 14 of 65 NL-94 C₀ parent plants were selected based on biomass yield of half-sib (HS) progeny tested for one post-establishment year under HYE and LYE conditions. Nine of the 14 C₀ parent plants were the same based on HS performance under HYE and LYE. Selected plants were intercrossed to produce NL-94 HYE and NL-94 LYE C₁ populations. One hundred and twenty-five HS C₁ progeny families (60 NL-94 HYE and 65 NL-94 LYE) were evaluated for biomass yield for 3 years (2002–2004) under HYE and LYE conditions. The HYE produced about 2.5 times higher biomass yields than the LYE in both C₀ and C₁ HS progeny tests. Estimated additive genetic variance and predicted gains from selection (ΔG) were high in the C₁ populations indicating that RSGCA should achieve higher biomass yields. Mean biomass yields of C₁ HS families originating from the LYE protocol were significantly higher than those of families originating from the HYE protocol in both HYE and LYE performance tests, suggesting greater selection response under LYE in the C₀ population. The estimates of narrow-sense heritability ( ) and ΔG from the C₁ populations indicate that positive response to selection for biomass yield is possible in subsequent cycles of selection under either HYE or LYE, with a possible small advantage for HYE.     

Genetic variation in Eucalyptus camaldulensis and E. tereticornis for early growth and susceptibility to the gall wasp Leptocybe invasa in China

The gall wasp Leptocybe invasa is a major insect pest on plantation Eucalyptus in many countries. Since appearing in China in 2007 it has had major impacts on commercial plantations—some commonly planted Eucalyptus varieties have proven particularly susceptible, including hybrids involving Eucalyptus camaldulensis and E. tereticornis parent species. Intra-specific variation within each species for L. invasa susceptibility was examined in two seed source and family trials in southwest of Guangdong. The E. camaldulensis trial included 101 seedlots representing five natural stand and six seed orchard sources which also represented three sub-specific taxa. The E. tereticornis trial included 143 seedlots representing 11 natural stand and four seed orchard sources, including breeding seed orchards in China. Both trials were assessed for susceptibility to L. invasa along with height at age 9 months. Sub-specific taxa within E. camaldulensis differed significantly (P < 0.01) in L. invasa susceptibility but not height or survival; subsp. acuta had the lowest average susceptibility and subsp. simulata and obtusa were of intermediate susceptibility whilst material of uncertain sub-specific taxa from India had the highest average susceptibility. In E. tereticornis regions of origin and seed sources within regions differed significantly (P < 0.01) for both L. invasa susceptibility and height; the region China (all somewhat improved sources) had both the best average height growth and lowest susceptibility whilst the region Australia (all natural stand sources) proved inferior to China for both average susceptibility and height. A strong significant correlation was found between seed source average L. invasa susceptibility and annual rainfall at seed source geographic origin in E. tereticornis (r = ?0.873; P < 0.01), implying that seedlots from higher rainfall environments are markedly less susceptible to L. invasa. The equivalent parameter in E. camaldulensis was also strong (r = ?0.730) though not significant, perhaps due to having only five data points available. Differences between families within seed sources for both L. invasa susceptibility and height growth were also highly significant (P < 0.01) with the former trait proving moderately to strongly heritable (h _i ²  = 0.54 ± 0.40 in E. camaldulensis; 0.52 ± 0.50 in E. tereticornis). Height had low to moderate heritability in both species (h _i ²  = 0.11 ± 0.15 and 0.26 ± 0.08 respectively). Tree height and L. invasa susceptibility showed a moderate negative (favourable) genetic correlation in E. camaldulensis (?0.33 ± 0.64) and a moderate to strong negative (favourable) genetic correlation in E. tereticornis (?0.47 ± 0.31). Corresponding phenotypic correlations, though significant, were somewhat weaker (?0.16 and ?0.29 respectively), indicating a trend for taller trees to have lower levels of L. invasa susceptibility.     

Effects of short-term light to heavy exercise on gastric ulcer development in horses and efficacy of omeprazole paste in preventing gastric ulceration

OBJECTIVE: To determine the effects of 8 days of light to heavy exercise on gastric ulcer development in horses and determine the efficacy of omeprazole paste in preventing gastric ulceration. DESIGN: Randomized, controlled, multicenter clinical trial. ANIMALS: 102 horses with normal-appearing gastric mucosa on endoscopic examination that were in light to heavy training. PROCEDURES: Horses at 4 trial locations were allocated into replicates and sham dosed orally (empty syringe) or treated with a paste formulation of omeprazole (1 mg/kg [0.45 mg/ lb], PO) once daily for 8 days. Training regimens varied among locations and included early training for western performance events; walking, trotting, and cantering in a mechanical exerciser; and race training (2 locations). Prevalences of gastric ulceration at the completion of the 8-day treatment period were compared between groups. RESULTS: At the end of the 8-day treatment period, the proportion of omeprazole-treated horses free from gastric ulceration (88%) was significantly higher than the proportion of sham-dosed horses free from gastric ulceration (27%). CONCLUSIONS AND CLINICAL RELEVANCE: Results showed that horses in light to heavy training for as short as 8 days were at risk of developing gastric ulcers and that administration of omeprazole paste decreased the incidence of gastric ulcers.     

Resistance to plant viruses: Obtaining genes by non-conventional approaches

Summary Plant viruses cause considerable losses to crops and none of the three current approaches to disease control are likely to give the long-term answer. The new concept of non-conventional protection, in which the expression of a viral or virus-related sequence in the plant genome interferes with the virus infection cycle, holds considerable promise for designing new resistance or protection genes. A series of targets in the viral genome is identified and a range of mechanisms for attacking those targets is discussed. There are several current systems which have been proved to give protection, at least to a certain extent, and many systems which are being researched upon for the future. Some of these are described to give a picture of the current situation and of the thinking for the future. The problems of field deployment of the transgenic plants are discussed, especially those associated with the risk to the environment. Various questions which molecular biologists and plant breeders will have to consider include what are desirable characters to have in protection genes and how these new genes should be deployed.