Carnivorous plants of Nepenthes species have evolved particular organs named pitchers at the tips of their conspicuous leaves, allowing slippery trapping and effective digesting prey to acquire sufficient growing nutr...Carnivorous plants of Nepenthes species have evolved particular organs named pitchers at the tips of their conspicuous leaves, allowing slippery trapping and effective digesting prey to acquire sufficient growing nutrients. Nepenthes pitchers are generally distinguished by several morphological regions exhibiting distinct functions in prey capturing, and combined effect of the several zones results in great trapping efficiency. Depending on specific micro-structures, slippery zone performs an important role in efficiently preying arthropods, and this prey ability inspires an idea for biomimetic development of slippery trapping plate used in controlling agricultural pests. In this paper, combined with our latest results, the authors introduced the recent studies of the slippery zone, including surface structures and anti-attachment functions. They also highlighted the biomimetic application of slippery zone in developing slippery trapping plate for controlling agricultural pest.展开更多
Milk acts as a suitable peripheral culture for growth and propagation of different kinds of micro organisms. During the process of producing cheese, some micro organisms such as Escherichia coli, Coliform, Staphylococ...Milk acts as a suitable peripheral culture for growth and propagation of different kinds of micro organisms. During the process of producing cheese, some micro organisms such as Escherichia coli, Coliform, Staphylococcus, Mold and Yeast may cause its contamination. In respect to the fact that pitcher cheese is produced in traditional way in different regions in West Azarbayjan, the aim of this research is examining the rate of contamination of pitcher cheese in West Azarbayjan. About 42 samples of pitcher cheese were gathered under strill condition from different parts of West Azarbayjan. In order to study microbes contamination, the samples were examined by standard microbiologic ways in laboratory from the 42 samples of pitcher cheese, four samples were contaminated by Staphylococcus aureus coagulase positive, 16 samples were contaminated by E. Coli, 21 samples by Coliform, 17 samples by mold and yeast. The producing and delivering should be controlled because of the rate of contamination in pitcher cheese and this kind of cheese should be produced in half industrial way by controlling and making special facilities for pitcher cheese producers.展开更多
This study attempts to investigate how the slippery surface of Nepenthes alata pitchers restricts the attachment ability of ant Camponotus japonicus Mayr, via climbing behavior observation and friction force measureme...This study attempts to investigate how the slippery surface of Nepenthes alata pitchers restricts the attachment ability of ant Camponotus japonicus Mayr, via climbing behavior observation and friction force measurement. Ants exhibited ineffective climbing behaviors and rather small friction forces when attached to upward-oriented slippery surfaces, but opposite phenomena were shown when on inverted surfaces. Friction forces of intact, claw tip-removed and pad-destroyed ants were measured on intact and de-waxed slippery surfaces, exploring the roles of wax crystals and lunate cells in restricting ant＇s attachment. On downward-directed slippery surfaces, greater forces were exhibited by intact and pad-destroyed ants; on the two slippery sur- faces, pad-destroyed ants presented slightly smaller forces and clawless ants generated considerably smaller forces. Somewhat different force was provided by clawless ants on upward and downward oriented slippery surfaces, and slightly higher force was shown when ants climbed on wax-removed surface. Results indicate that the lunate cells contribute greatly to decrease the friction force, whereas the wax crystals perform a supplementary role. Mechanical analysis suggests that the directionally growing lunate cells possess a sloped structure that effectively prevents the claw＇s mechanical interlock, reducing the ant＇s attachment ability considerably. Our conclusion supports a further interpretation of slippery surface＇s anti-attachment mecha- nism, also provides theoretical reference to develop biomimetic slippery plate to trap agricultural insect.展开更多
为进一步明确影响棒球投手投球速度的关键因素,通过中国知网、Web of Science和PubMed等平台以棒球投手、投球速度、运动生物力学和鞭打动作等为关键词,检索并整理归纳20世纪90年代至今的相关文献资料。通过对比国内外优秀棒球投手投球...为进一步明确影响棒球投手投球速度的关键因素,通过中国知网、Web of Science和PubMed等平台以棒球投手、投球速度、运动生物力学和鞭打动作等为关键词,检索并整理归纳20世纪90年代至今的相关文献资料。通过对比国内外优秀棒球投手投球速度和专项技术能力,发现投球时投掷臂肩关节外旋角度、肩关节水平外展角度、肘关节角度、躯干前倾幅度、前腿膝关节角度等运动学指标,投掷臂各环节受力峰值、前腿受到的最大地面反作用力等动力学指标均对投球速度起关键性影响作用。教练员和棒球投手可通过改善上下肢关节角度和角速度等指标参数的大小、增强肌肉力量和柔韧性等手段,完善投手投球技术动作,提高投球速度。展开更多
文摘Carnivorous plants of Nepenthes species have evolved particular organs named pitchers at the tips of their conspicuous leaves, allowing slippery trapping and effective digesting prey to acquire sufficient growing nutrients. Nepenthes pitchers are generally distinguished by several morphological regions exhibiting distinct functions in prey capturing, and combined effect of the several zones results in great trapping efficiency. Depending on specific micro-structures, slippery zone performs an important role in efficiently preying arthropods, and this prey ability inspires an idea for biomimetic development of slippery trapping plate used in controlling agricultural pests. In this paper, combined with our latest results, the authors introduced the recent studies of the slippery zone, including surface structures and anti-attachment functions. They also highlighted the biomimetic application of slippery zone in developing slippery trapping plate for controlling agricultural pest.
文摘Milk acts as a suitable peripheral culture for growth and propagation of different kinds of micro organisms. During the process of producing cheese, some micro organisms such as Escherichia coli, Coliform, Staphylococcus, Mold and Yeast may cause its contamination. In respect to the fact that pitcher cheese is produced in traditional way in different regions in West Azarbayjan, the aim of this research is examining the rate of contamination of pitcher cheese in West Azarbayjan. About 42 samples of pitcher cheese were gathered under strill condition from different parts of West Azarbayjan. In order to study microbes contamination, the samples were examined by standard microbiologic ways in laboratory from the 42 samples of pitcher cheese, four samples were contaminated by Staphylococcus aureus coagulase positive, 16 samples were contaminated by E. Coli, 21 samples by Coliform, 17 samples by mold and yeast. The producing and delivering should be controlled because of the rate of contamination in pitcher cheese and this kind of cheese should be produced in half industrial way by controlling and making special facilities for pitcher cheese producers.
基金We acknowledge Zhao Lei （The State Key Labo- ratory of Tribology, TsingHua University） for helping in the SWLI examinations. We sincerely thank the National Natural Science Foundation of China （No. 51205107）, the Natural Science Foundation of Hebei province （No. E2014208056）, and the Tribology Science Fund of State Key Laboratory of Tribology （No. SKLTKF13B05） for their financial supports.
文摘This study attempts to investigate how the slippery surface of Nepenthes alata pitchers restricts the attachment ability of ant Camponotus japonicus Mayr, via climbing behavior observation and friction force measurement. Ants exhibited ineffective climbing behaviors and rather small friction forces when attached to upward-oriented slippery surfaces, but opposite phenomena were shown when on inverted surfaces. Friction forces of intact, claw tip-removed and pad-destroyed ants were measured on intact and de-waxed slippery surfaces, exploring the roles of wax crystals and lunate cells in restricting ant＇s attachment. On downward-directed slippery surfaces, greater forces were exhibited by intact and pad-destroyed ants; on the two slippery sur- faces, pad-destroyed ants presented slightly smaller forces and clawless ants generated considerably smaller forces. Somewhat different force was provided by clawless ants on upward and downward oriented slippery surfaces, and slightly higher force was shown when ants climbed on wax-removed surface. Results indicate that the lunate cells contribute greatly to decrease the friction force, whereas the wax crystals perform a supplementary role. Mechanical analysis suggests that the directionally growing lunate cells possess a sloped structure that effectively prevents the claw＇s mechanical interlock, reducing the ant＇s attachment ability considerably. Our conclusion supports a further interpretation of slippery surface＇s anti-attachment mecha- nism, also provides theoretical reference to develop biomimetic slippery plate to trap agricultural insect.
文摘为进一步明确影响棒球投手投球速度的关键因素,通过中国知网、Web of Science和PubMed等平台以棒球投手、投球速度、运动生物力学和鞭打动作等为关键词,检索并整理归纳20世纪90年代至今的相关文献资料。通过对比国内外优秀棒球投手投球速度和专项技术能力,发现投球时投掷臂肩关节外旋角度、肩关节水平外展角度、肘关节角度、躯干前倾幅度、前腿膝关节角度等运动学指标,投掷臂各环节受力峰值、前腿受到的最大地面反作用力等动力学指标均对投球速度起关键性影响作用。教练员和棒球投手可通过改善上下肢关节角度和角速度等指标参数的大小、增强肌肉力量和柔韧性等手段,完善投手投球技术动作,提高投球速度。
