AIM:To compare the influence and clearance effect of enzymatic and non-enzymatic detergents against Escherichia coli (E. coli) biofilm on the inner surface of gastroscopes.METHODS:Teflon tubes were incubated in a mixt...AIM:To compare the influence and clearance effect of enzymatic and non-enzymatic detergents against Escherichia coli (E. coli) biofilm on the inner surface of gastroscopes.METHODS:Teflon tubes were incubated in a mixture of different detergents and E. coli culture (106 CFU/mL) for 72 h at 15℃,and biofilms on the inner surface of the teflon tubes were analyzed by bacterial count and scanning electron microscopy. To evaluate the clear-ance effect of detergents,after biofilms were formed on the inner surface of Teflon tubes by 72 h lavage with E. coli culture,tubes were lavaged by enzymatic and non-enzymatic detergents at a speed of 250 mL/min,then biofilms on the inner surface were analyzed by bacterial count and scanning electron microscopy.RESULTS:Non-enzymatic detergent had a better inhi-bition function on biofilm formation than enzymatic de-tergent as it reduced bacterial burden by 2.4 log compared with the control samples (P = 0.00). Inhibition function of enzymatic detergent was not significantly different to that of control samples and reduced bac-terial burden by 0.2 log on average (P > 0.05). After lavaging at 250 mL/min for 3 min,no living bacteria were left in the tubes. Scanning electron microscopy observation showed biofi lms became very loose by the high shear force effect. CONCLUSION:Non-enzymatic detergent has a better inhibition effect on biofilm formation at room temperature. High speed pre-lavage and detergents are very important in temporal formed biofilm elimination.展开更多
The cuticle, an essential structure for insects, is produced from cuticular proteins and chitin via a series of biochemical reactions. Tweedle genes are important members of the cuticular protein family and have four ...The cuticle, an essential structure for insects, is produced from cuticular proteins and chitin via a series of biochemical reactions. Tweedle genes are important members of the cuticular protein family and have four conserved motifs binding to chitin. Tweedle family genes have been found to play a profound effect on cuticle development. Here, we report that the cuticular protein gene LmTwdll ofLocusta migratoria belongs to the Tweedle family. In situ hybridization showed that LmTwdll is localized to epidermal cells of the cuticle. The expression patterns of LmTwdll showed low expression in the cuticle during the early and middle stages of the fifth-instar nymphs; in contrast, its expression rapidly increased in the late stages of fifth-instar nymphs. We performed RNA interference to examine the function of LmTwdll in locusts. Silencing of LmTwdll resulted in high mortality during the molting process before the next stage. Also, the epicuticle of nymphs failed to molt, tended to be thinner and the arrangement of chitin in the procuticle appeared to be disordered compare to the control group. These results demonstrate that LmTwdl! plays a critical role in molting, which contributes to a better understanding of the distinct functions of the Tweedle family in locusts.展开更多
分析 BP 神经网络应用于小康水利综合评价中存在的几个关键性问题。利用层次分析法（AHP）从100余个水利统计指标中遴选出30个具有一定代表性的指标用于构建小康水利综合评价指标体系并给出相应的分级标准；采用 LM 算法弥补标准 BP 神...分析 BP 神经网络应用于小康水利综合评价中存在的几个关键性问题。利用层次分析法（AHP）从100余个水利统计指标中遴选出30个具有一定代表性的指标用于构建小康水利综合评价指标体系并给出相应的分级标准；采用 LM 算法弥补标准 BP 神经网络在实际应用中存在收敛速度慢、易陷入局部极值等不足,建立了神经网络小康水利综合评价模型---LM-BP 模型；利用随机内插方法在小康水利综合评价分级标准阈值间生成训练样本和检验样本；提出网络拟合度的概念；选取网络拟合度、平均相对误差等5个统计指标用于评价模型性能。在模型达到预期的评价精度和泛化能力后,将其用于文山州小康水利综合评价,并构建传统 BP 模型、RBF 模型作为对比模型。结果表明：（a）无论是训练样本还是检验样本,LM-BP 模型的评价精度均高于传统 BP 神经网络模型、RBF 神经网络模型近一个数量级,表明 LM-BP 模型具有较高的评价精度和泛化能力,可用于文山州小康水利综合评价,模型收敛速度快、稳定性能好。（b）2010年文山州及各县级行政区小康水利综合评价为1~2级,处于起步-基本实现阶段；2020年预测评价为3级,全州基本实现小康水利。展开更多
A lagoon in the New Binhai District, a high-speed developing area, Tianjin, China, has long been receiving the mixed chemical industrial wastewater from a chemical industrial park. This lagoon contained complex hazard...A lagoon in the New Binhai District, a high-speed developing area, Tianjin, China, has long been receiving the mixed chemical industrial wastewater from a chemical industrial park. This lagoon contained complex hazardous substances such as heavy metals and accumulative pollutants which stayed over time with a poor biodegradability. According to the characteristics of wastewater in the lagoon, the micro-electrolysis process was applied to improve the biodegradability before the bioprocess treatment. By the orthogonal experimental study of main factors influencing the efficiency of the treatment method, the best control parameters were obtained, including pH=2.0, a volume ratio of Fe and reaction wastewater of 0.03750, a volume ratio of Fe and the granular activated carbon (GAC) of 2.0, a mixing speed of 200 r/min, and a hydraulic retention time (HRT) of 1.5 h. In the meantime, the removal rate of chemical oxygen demand (COD) was up to 64.6%, and NH4+-N and Pb in the influent were partly removed. After the micro-electrolysis process, the ratio of biochemical oxygen demand (BOD) to COD (B/C ratio) was greater than 0.6, thus providing a favorable basis for bioprocess treatment.展开更多
Various force disturbances influence the thrust force of linear motors when a linear motor （LM） is running. Among all of force disturbances, the force ripple is the dominant while a linear motor runs in low speed. I...Various force disturbances influence the thrust force of linear motors when a linear motor （LM） is running. Among all of force disturbances, the force ripple is the dominant while a linear motor runs in low speed. In order to suppress the force ripple, back propagation（BP） neural network is proposed to learn the function of the force ripple of linear motors, and the acquisition method of training samples is proposed based on a disturbance observer. An off-line BP neural network is used mainly because of its high running efficiency and the real-time requirement of the servo control system of a linear motor. By using the function, the force ripple is on-line compensated according to the position of the LM. The experimental results show that the force ripple is effectively suppressed by the compensation of the BP neural network.展开更多
基金Supported by Medical and Health Research Foundation of Zhejiang Province, China, No. 2007B040, 2007B039
文摘AIM:To compare the influence and clearance effect of enzymatic and non-enzymatic detergents against Escherichia coli (E. coli) biofilm on the inner surface of gastroscopes.METHODS:Teflon tubes were incubated in a mixture of different detergents and E. coli culture (106 CFU/mL) for 72 h at 15℃,and biofilms on the inner surface of the teflon tubes were analyzed by bacterial count and scanning electron microscopy. To evaluate the clear-ance effect of detergents,after biofilms were formed on the inner surface of Teflon tubes by 72 h lavage with E. coli culture,tubes were lavaged by enzymatic and non-enzymatic detergents at a speed of 250 mL/min,then biofilms on the inner surface were analyzed by bacterial count and scanning electron microscopy.RESULTS:Non-enzymatic detergent had a better inhi-bition function on biofilm formation than enzymatic de-tergent as it reduced bacterial burden by 2.4 log compared with the control samples (P = 0.00). Inhibition function of enzymatic detergent was not significantly different to that of control samples and reduced bac-terial burden by 0.2 log on average (P > 0.05). After lavaging at 250 mL/min for 3 min,no living bacteria were left in the tubes. Scanning electron microscopy observation showed biofi lms became very loose by the high shear force effect. CONCLUSION:Non-enzymatic detergent has a better inhibition effect on biofilm formation at room temperature. High speed pre-lavage and detergents are very important in temporal formed biofilm elimination.
基金This research was supported by the National Natural Science Foundation of China Grants （Nos. 31472051, 31201710）, Natural Science Foundation of Shanxi Province of China （2014011028-3）, Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province, the Platform Project of Science and Technology in Shanxi Province （2015091010）, and National Basic Research Program of China （No. 2012CB114102）. We thank Dr. Feng Jiang for critical comments on the manuscript.
文摘The cuticle, an essential structure for insects, is produced from cuticular proteins and chitin via a series of biochemical reactions. Tweedle genes are important members of the cuticular protein family and have four conserved motifs binding to chitin. Tweedle family genes have been found to play a profound effect on cuticle development. Here, we report that the cuticular protein gene LmTwdll ofLocusta migratoria belongs to the Tweedle family. In situ hybridization showed that LmTwdll is localized to epidermal cells of the cuticle. The expression patterns of LmTwdll showed low expression in the cuticle during the early and middle stages of the fifth-instar nymphs; in contrast, its expression rapidly increased in the late stages of fifth-instar nymphs. We performed RNA interference to examine the function of LmTwdll in locusts. Silencing of LmTwdll resulted in high mortality during the molting process before the next stage. Also, the epicuticle of nymphs failed to molt, tended to be thinner and the arrangement of chitin in the procuticle appeared to be disordered compare to the control group. These results demonstrate that LmTwdl! plays a critical role in molting, which contributes to a better understanding of the distinct functions of the Tweedle family in locusts.
文摘分析 BP 神经网络应用于小康水利综合评价中存在的几个关键性问题。利用层次分析法（AHP）从100余个水利统计指标中遴选出30个具有一定代表性的指标用于构建小康水利综合评价指标体系并给出相应的分级标准；采用 LM 算法弥补标准 BP 神经网络在实际应用中存在收敛速度慢、易陷入局部极值等不足,建立了神经网络小康水利综合评价模型---LM-BP 模型；利用随机内插方法在小康水利综合评价分级标准阈值间生成训练样本和检验样本；提出网络拟合度的概念；选取网络拟合度、平均相对误差等5个统计指标用于评价模型性能。在模型达到预期的评价精度和泛化能力后,将其用于文山州小康水利综合评价,并构建传统 BP 模型、RBF 模型作为对比模型。结果表明：（a）无论是训练样本还是检验样本,LM-BP 模型的评价精度均高于传统 BP 神经网络模型、RBF 神经网络模型近一个数量级,表明 LM-BP 模型具有较高的评价精度和泛化能力,可用于文山州小康水利综合评价,模型收敛速度快、稳定性能好。（b）2010年文山州及各县级行政区小康水利综合评价为1~2级,处于起步-基本实现阶段；2020年预测评价为3级,全州基本实现小康水利。
基金Project supported by the National Natural Science Foundation of China (No. 70833003)the National Science and Technology Support Project of 11th 5-Year Plan, China (No. 200603746006)
文摘A lagoon in the New Binhai District, a high-speed developing area, Tianjin, China, has long been receiving the mixed chemical industrial wastewater from a chemical industrial park. This lagoon contained complex hazardous substances such as heavy metals and accumulative pollutants which stayed over time with a poor biodegradability. According to the characteristics of wastewater in the lagoon, the micro-electrolysis process was applied to improve the biodegradability before the bioprocess treatment. By the orthogonal experimental study of main factors influencing the efficiency of the treatment method, the best control parameters were obtained, including pH=2.0, a volume ratio of Fe and reaction wastewater of 0.03750, a volume ratio of Fe and the granular activated carbon (GAC) of 2.0, a mixing speed of 200 r/min, and a hydraulic retention time (HRT) of 1.5 h. In the meantime, the removal rate of chemical oxygen demand (COD) was up to 64.6%, and NH4+-N and Pb in the influent were partly removed. After the micro-electrolysis process, the ratio of biochemical oxygen demand (BOD) to COD (B/C ratio) was greater than 0.6, thus providing a favorable basis for bioprocess treatment.
基金National Natural Science Foundation of China(No. 60474021)
文摘Various force disturbances influence the thrust force of linear motors when a linear motor （LM） is running. Among all of force disturbances, the force ripple is the dominant while a linear motor runs in low speed. In order to suppress the force ripple, back propagation（BP） neural network is proposed to learn the function of the force ripple of linear motors, and the acquisition method of training samples is proposed based on a disturbance observer. An off-line BP neural network is used mainly because of its high running efficiency and the real-time requirement of the servo control system of a linear motor. By using the function, the force ripple is on-line compensated according to the position of the LM. The experimental results show that the force ripple is effectively suppressed by the compensation of the BP neural network.
