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Effects of husbandry systems and Chinese indigenous chicken strain on cecum microbial diversity
Dong Xiuxue,Hu Bing,Wan Wenlong,Gong Yanzhang,Feng Yanping 아세아·태평양축산학회 2020 Animal Bioscience Vol.33 No.10
Objective: This study was to evaluate the effect of husbandry systems and strains on cecum microbial diversity of Jingyang chickens under the same dietary conditions. Methods: A total of 320 laying hens (body weight, 1.70±0.15 kg; 47 weeks old) were randomly allocated to one of the four treatments: i) Silver-feathered hens in enrichment cages (SEC) with an individual cage (70×60×75 cm), ii) Silver-feathered hens in free range (SFR) with the stocking density of 1.5 chickens per ten square meters, iii) Gold-feathered hens in enrichment cages (GEC), iv) Gold-feathered hens in free range (GFR). The experiment lasted 8 weeks and the cecum fecal samples were collected for 16S rDNA high throughput sequencing at the end of experiment. Results: i) The core microbiota was composed of Bacteroidetes (49% to 60%), Firmicutes (21% to 32%) and Proteobacteria (2% to 4%) at the phylum level. ii) The core bacteria were Bacteroides (26% to 31%), Rikenellaceae (9% to 16%), Parabacteroides (2% to 5%) and Lachnoclostridium (2% to 6%) at the genus level. iii) The indexes of operational taxonomic unit, Shannon, Simpson and observed species were all higher in SFR group than in SEC group while in GEC group than in GFR group, with SFR group showing the greatest diversity of cecum microorganisms among the four groups. iv) The clustering result was consistent with the strain classification, with a similar composition of cecum bacteria in the two strains of laying hens. Conclusion: The core microbiota were not altered by husbandry systems or strains. The free-range system increased the diversity of cecal microbes only for silver feathered hens. However, the cecum microbial composition was similar in two strain treatments under the same dietary conditions.
Fuwu Yan,Junjun Wang,Dong Yan,Wenlong Zhang,Guoqing Zhang,Jizhou Zhang,Ziyi Chen,Yu Wang 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.4
This paper studied the effects of water injection on combustion, emissions and knock. The results showed that direct water injection (DWI) absorbed more heat than inlet port water injection (PWI), resulting in lower cylinder pressure, higher oxygen content and longer combustion duration. And the turbulence kinetic energy of DWI model was greater, resulting in lower soot and CO emissions of DWI. Furthermore, the cooling effect of exhaust port side WI was better than intake port side, which reduced NOX emission. Besides, the injection pressure of single injector WI was higher than double injector, which increased the combustion duration and reduced the cylinder pressure. The decrease of temperature under water dilution was the main reason for the reduction of NOX, while the increase of incomplete combustion increased the soot and CO emission. Finally, with the same amount of WI, the knock suppression effect of DWI models was better than PWI models. The knock intensity (KI) of all models decreased gradually with the increase of water, and DWI models decreased more rapidly. For PWI models, when the amount of water became smaller, the engine pressure fluctuation of certain areas in the cylinder increased slightly, weakening the influence of WI on engine knock.
Lingdong Meng,Lijun Han,Hexuan Zhu,Wenlong Dong,Wei Li 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.4
There is a wide distribution of weakly cemented argillaceous rock masses in areas where there are many coal mines, and their complex characteristics make them more difficult to support. This paper researches this type of rock and studies the slurry diffusion mechanism and grouting reinforcement characteristics of injected rock mass and their relationship with compaction and splitting grouting. The grouting mode is dominated by compaction and splitting. The rheological behavior of cement slurries with different concentrations used in split grouting was studied. The existing grouting equipment was improved, and grouting tests were performed on loose aggregates of weakly cemented primary rock in a certain size range. Subsequently, basic physical parameter determination tests, microscopic tests, and uniaxial tests were performed on grout, and the effects of grouting pressure, moisture content of standard samples, slurry water/cement ratio, and curing time on grouting reinforcement were analyzed. During the grouting process, the pattern of plasma pulse diffusion and reinforcement was summarized as three types: compaction, splitting, and microcracking. The failure modes of rock were summarized as shear failure, shear failure along the interface of the plasma, and splitting damage.
Lingdong Meng,Lijun Han,Hexuan Zhu,Wenlong Dong,Wei Li 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.11
To study the mechanisms and potential control measures for coal mine engineering safety hazards caused by swelling rock, water absorption experiments were performed under different temperature by using an independently developed rock water absorption test system. The swelling pressure, expansion amount and water absorption amount of specimens were monitored in real time. Nuclear magnetic resonance and uniaxial compression experiments were performed. The water absorption rate of the swelling rock specimens increases significantly with increasing water absorption time. The water absorption capacity of the specimens differs considerably under different temperatures. The water absorption curve can be divided into three stages: the severe stage, deceleration stage and equilibrium stage. The water absorption amount and water absorption rate are linearly related to temperature. The curve of the swelling pressure depicts a double peak shape. The expansion curve can also be divided into three stages. With increasing temperature, the expansion rate increases, and the time needed to achieve expansion stability is prolonged. There is a negative linear correlation between the uniaxial compressive strength and the moisture content. The higher the temperature is, the higher the moisture content. The increase in the rock porosity after water absorption is one of the important factors driving the strength attenuation.
Hexuan Zhu,Lijun Han,Qingbin Meng,Jun Liu,Lingdong Meng,Wenlong Dong 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.5
Quick-setting grout has time-varying characteristics, and the space porosity of the injected medium changes after being grouted. The above two points need to be considered when loose and broken coal rock masses are grouted with rapid-setting grout. In other words, the coupling effect of the slurry-coal rock mass causes the slurry to exhibit the temporal and spatial characteristics of slurry viscosity (TSCSV). Based on the Bingham fluid constitutive model, a capillary group model with a linear increase in diameter was created, and a one-dimensional penetration grout diffusion model was established considering the TSCSV. The one-dimensional visualization splitting-permeation grout diffusion simulation test system was designed to obtain the space porosity of the broken coal rock mass under different final grouting pressures to obtain the law of the changes in grouting pressure and diffusion height with time under the condition of a fixed grouting rate. Furthermore, the mechanism of splitting-permeation grouting in loose and broken coal rock masses is analysed in depth considering the TSCSV. The results showed that the space porosity of coal rock masses increases linearly. In addition, the calculated value of the slurry diffusion distance was 0.93 − 1.1 times the experimental value considering the TSCSV. The calculated value was in good agreement with the experimental value. The calculated value of the final pressure of orifice grouting was approximately 1.5 times the test value without considering the unevenness of the space porosity distribution (USPD). The grouting pressure was overestimated without considering the USPD. Therefore, the TSCSV of the quick-setting slurry should be fully considered in the grouting design.
Bo Xu,Yingzhe WANG,Shixin ZHU,Haizhu ZHOU,Changlong GOU,Wenlong DONG,Yu Wang,Yunhang GAO,Hongxia MA 한국곤충학회 2019 Entomological Research Vol.49 No.1
Chalkbrood, which results from Ascosphaera apis infection, is one of the bee diseases that causes serious damage to the bee colony. Understanding the molecular bases underlying immune response to chalkbrood disease would facilitate the genetic breeding of bees by selecting races with superior chalkbrood resistance. In this study, transcriptome sequencing was performed to identify genes and pathways involved in the immune response to As. apis infection in A. mellifera larvae. In total, 2,890 differentially expressed genes (DEGs) (FDR < 0.001) were identified between the healthy and As. apis infected bee larvae, including 2,214 up‐regulated and 676 down‐regulated unigenes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway classification of the DEGs revealed association with development, energy metabolism, signal transduction, disease, and immune response. Among the immune‐related genes, p38, toll‐like receptors (TLRs), integrin, and antimicrobial peptides were up‐regulated under As. apis infection. This study provides valuable gene transcriptional information towards the investigation of molecular mechanisms related to chalkbrood immune response and host pathogenesis in A. mellifera.