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Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements

Journal of Traffic and Transportation Engineering(English Edition) 2016年第5期3卷 475-482页

作者： Shuo Li dwayne harris Tim Wells Division of Research and Development Indiana Department of Transportation

Recently, diamond grinding has gained increasing attention as pavement preservation treatment to restore desired surface characteristics, particularly friction. Compared to other pavement preservation treatments such as surface overlays and high friction surface treat- ments, diamond grinding may cost less, save construction time, or require minimum maintenance. Diamond grinding produces longitudinal, continuous, and line-type texture that contains corrugations with evenly spaced ridges. The improved surface texture will immediately enhance pavement surface friction and reduce the possibility of hydroplaning in rainy weather. However, little information has been documented on the texture charac- teristics and long-term friction performance of diamond-ground pavements. A field evalu- ation was conducted to examine the surface texture and friction characteristics in diamond- ground concrete and asphalt pavements by the authors. Five pavement test sections, including two diamond-ground concrete pavements, one diamond-ground concrete bridge deck, one diamond-ground asphalt pavement, and one transversely tined concrete pave- ment, were selected for evaluation. Laser scanner testing was performed to capture both macro and microtexture profiles. Locked wheel testing was performed to measure the fric- tion numbers. The test results were examined and compared so as to evaluate two performances, after construction and long-term friction performance of diamond-ground pavements. It was found that longitudinal diamond grinding can provide durable, satisfactory surface friction performance for both concrete and asphalt pavements.

关键词： Concrete pavement Asphalt pavement Surface friction Diamond-grinding Macrotexture Microtexture

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In vitro and in vivo application of RNA interference for targeting genes involved in peritrophic matrix synthesis in a lepidopteran system

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Insect Science 2013年第1期20卷 92-100页

作者： Umut Toprak Doug Baldwin Martin Erlandson Cedric Gillott Stephanie harris dwayne D. Hegedus Agriculture and Agri-Food Canada Ottawa Ontario Canada Department of Biology University of Saskatchewan Canada Department of Plant Protection Faculty of Agriculture University of Ankara Turkey Department of Food and Bioproduct Sciences University of Saskatchewan Saskatoon SK Canada

The midgut of most insects is lined with a semipermeable acellular tube, the peritrophic matrix （PM）, composed of chitin and proteins. Although various genes encoding PM proteins have been characterized, our understanding of their roles in PM structure and function is very limited. One promising approach for obtaining functional information is RNA interference, which has been used to reduce the levels of specific mRNAs using double-stranded RNAs administered to larvae by either injection or feeding. Although this method is well documented in dipterans and coleopterans, reports of its success in lepidopterans are varied. In the current study, the silencing midgut genes encoding PM proteins （insect intestinal mucin 1, insect intestinal mucin 4, PM protein 1） and the chitin biosynthetic or modifying enzymes （chitin synthase-B and chitin deacetylase 1） in a noctuid lepidopteran, Mamestra configurata, was examined in vitro and in vivo. In vitro studies in primary midgut epithelial cell preparations revealed an acute and rapid silencing （by 24 h） for the gene encoding chitin deacetylase 1 and a slower rate of silencing （by 72 h） for the gene encoding PM protein 1. Genes encoding insect intestinal mucins were slightly silenced by 72 h, whereas no silencing was detected for the gene encoding chitin synthase-B. In vivo experiments focused on chitin deacetylase 1, as the gene was silenced to the greatest extent in vitro. Continuous feeding of neonates and fourth instar larvae with double-stranded RNA resulted in silencing of chitin deacetylase 1 by 24 and 36 h, respectively. Feeding a single dose to neonates also resulted in silencing by 24 h. The current study demonstrates that genes encoding PM proteins can be silenced and outlines conditions for RNA interference by per os feeding in lepidopterans.

关键词： chitin deacetylase chitin synthase-B lepidoptera peritrophic matrix,peritrophin RNA interference

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