Lithological properties and weathering response on badland hillslopes

Rills and rill networks are important geomorphological features in clay-rich badland areas. Rill network geometry varies with climate and topography, but the lithological properties are also critical. Rill systems on mudrock and sandstone in Alberta badlands were studied to examine progressive changes in material properties as smectite-rich mudrocks and sandstones undergo weathering, and the impact of seasonal changes in precipitation patterns. Three plots with well developed rill systems on each unit were examined in May 2001 and 2003. Geometric properties were determined along a dense grid and surface and subsurface samples were analyzed for texture, crust structure (SEM), mineralogical composition (XRD), content of major elements (XRF), aggregate stability, and moisture content. The rill width/depth ratio decreased from 2001 to 2003 on mudrock rill networks. The “popcorn” crust found in 2001 changed to a thin dense crust in 2003. 2001 materials had higher Na and Ca concentrations and the 2003 materials have higher Al, K concentrations. Unweathered mudrock shards were subjected to incremental weathering in controlled laboratory conditions. Depending on moisture input, different crust types developed on materials after 10 wetting–drying cycles. Material responded to different amounts of precipitation by alteration from swelling to dispersion.     

Principal component analysis and discriminant analysis (PCA-DA) for discriminating profiles of terminal restriction fragment length polymorphism (T-RFLP) in soil bacterial communities

To assess the impact of a transgenic crop on soil environment, we compared soil bacterial communities from the rhizospheres of cucumber green mottle mosaic virus (CGMMV)-resistant transgenic watermelon (Citrullus vulgaris [Twinser] cv. Gongdae) and non-transgenic parental line watermelon at an experimental farm in Miryang, Korea. Soil microbial community structure was studied using terminal restriction fragment length polymorphism (T-RFLP) using HaeIII and HhaI enzymes on products from polymerase chain amplification reactions (PCR) of total DNA from rhizosphere. We used principal component analyses (PCA) to reduce dimensionality of T-RFLP profiles before comparison. On these PCA scores, we conducted discrimination analyses to compare soil microbial communities from the rhizosphere of transgenic and non-transgenic. Discriminant analyses indicate that microbial communities from rhizosphere of transgenic and non-transgenic watermelon did not differ with significance at 95% level. Our study could be used as a model case to assess the environmental risk assessment of transgenic crops on soil microbial organisms.     

蜂产品农兽药残留检测技术研究进展

蜂产品由于具有极高的营养价值而深受消费者的青睐。随着全球蜂产品消费量的逐渐扩大,农兽药残留的问题日益严重,危害人类的健康,影响蜂产品的出口。本文结合蜂产品农兽药残留的现状,重点阐述了农兽药残留检测的方法,并展望了未来蜂产品农兽药残留检测技术的发展趋势。     

Postnatal development of metallophilic macrophages in the rat thymus

Metallophilic macrophages (MMs) are a distinct cell type of the rodent thymus. Our previous research has focused on the morphological characteristics of MMs, as well as on the molecular mechanisms involved in the development and tissue positioning of these cells. However, the postnatal development of MMs has not been sufficiently studied. In the present study, we investigated the positioning of MMs in the rat thymus between postnatal day 0 (P0) and P30. On P0, MMs were evenly distributed all over the thymic tissue—that is, the cortex, cortico-medullary zone and medulla. From P0 to P15, the number of MMs in the thymic cortex significantly decreased, and after P15, this number did not change. Thus, the present study shows that on P15, MMs almost completely disappear from the thymic cortex and show their adult position in the cortico-medullary zone and in the medulla.     

栽培因素对北方粳稻产量及米质的影响——第8报 插秧时间对产量及米质的影响

不同插秧时间对产量及米质影响研究结果表明,晚插秧时对于水稻的株高生长、分蘖发育、叶龄增长都没有太大的影响,而影响最大的是千粒重,其次是平均每穗粒数。早插秧时每穴有效穗数有所减少。晚插秧时虽然有利于提高外观品质和食味品质,但不利于提高加工品质。本试验条件下,一般在5月25日前后5d开始和结束插秧,可以兼顾产量和米质。     

Characterization of PET/PP blend fiber and it’s application to wig

As PET (Polyester) fiber has better heat resistance than PVC fiber or modacryl fiber, it has been used as wig fiber for human hair alternatives. However, PET is heavier and has higher specific gravity than human hair, and therefore the authors attempted to make lighter wig fiber by blending PP (polypropylene) into PET by mixing the PET/PP blend with a compatibilizer, a ethylene-acrylic ester-GMA(EAG) component grafted material, to overcome poor compatibilities of PET and PP. The thermal properties of the PET/PP blend mixed with EAG were measured using DSC, and the results showed that EAG affected melting point and crystallization temperature of the blend polymer. As blend ratio of PP increased, specific gravity of blend fiber reduced and thermal shrinkage rate increased. Blend ratio of PP was greater for shorter lengths of initial curl, although curl loosening increased as time elapsed.     

Insecticidal activities of crude extracts and phospholipids from Chenopodium ficifolium against melon and cotton aphid, Aphis gossypii

Several organic solvent extracts of Chenopodium ficifolium were tested for their insecticidal activity against melon and cotton aphid, Aphis gossypii, on cucumber plants. Both methanol and ethanol extracts, at 5000 μg ml⁻¹, were highly active giving over 80% control. The other crude extracts displayed moderate or weak insecticidal activity giving control in the range of 16–69%. Two phospholipids were isolated as insecticidal active substances from C. ficifolium. Their chemical structures were identified as 1-palmitoyl-2-(3-trans)-hexadecenoyl-sn-glycero-3-phosphoglycerol and 1-palmitoyl-2-linoleoyl-3-glycerophosphocholine by GC–MS, EDS, mass and NMR spectral analyses. Both compounds displayed a dose-dependent mortality of A. gossypii. Furthermore, the liquid formulation that was obtained by partitioning with n-hexane from the methanol extract of C. ficifolium controlled melon and cotton aphid on cucumber plants effectively. These results indicate that extracts of C. ficifolium have potential for development as botanical insecticides for controlling A. gossypii infesting cucumber plants.