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Cu(In 4

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光催化 3

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Influences and mechanisms of nanofullerene on the horizontal transfer of plasmid-encoded antibiotic resistance genes between

Qingkun Ji, Caihong Zhang, Dan Li

《环境科学与工程前沿(英文)》 2020年 第14卷 第6期 doi: 10.1007/s11783-020-1287-0

摘要: Abstract • Sub-inhibitory levels of nC60 promote conjugative transfer of ARGs. • nC60 can induce ROS generation, oxidative stress and SOS response. • nC60 can increase cell membrane permeability and alter gene expression. • Results provide evidence of nC60 promoting antibiotic resistance dissemination. The spread and development of antibiotic resistance globally have led to severe public health problems. It has been shown that some non-antibiotic substances can also promote the diffusion and spread of antibiotic resistance genes (ARGs). Nanofullerene (nC60) is a type of nanomaterial widely used around the world, and some studies have discovered both the biological toxicity and environmental toxicity of nC60. In this study, cellular and molecular biology techniques were employed to investigate the influences of nC60 at sub-minimum inhibitory concentrations (sub-MICs) on the conjugation of ARGs between the E. coli strains. Compared with the control group, nC60 significantly increased the conjugation rates of ARGs by 1.32‒10.82 folds within the concentration range of 7.03‒1800 mg/L. This study further explored the mechanism of this phenomenon, finding that sub-MICs of nC60 could induce the production of reactive oxygen species (ROS), trigger SOS-response and oxidative stress, affect the expression of outer membrane proteins (OMPs) genes, increase membrane permeability, and thus promote the occurrence of conjugation. This research enriches our understanding of the environmental toxicity of nC60, raises our risk awareness toward nC60, and may promote the more rational employment of nC60 materials.

关键词: Nanofullerene     Sub-minimum inhibitory concentrations     Antibiotic resistance genes     Conjugation     Molecular biological techniques    

基于消费端的源解析表明不同区域对O<sub>3sub>浓度和健康效应的贡献 Article

Shengqiang Zhu, Peng Wang, Siyu Wang, Guannan Geng, Hongyan Zhao, Yuan Wang, Hongliang Zhang

《工程(英文)》 2023年 第28卷 第9期   页码 130-138 doi: 10.1016/j.eng.2022.11.011

摘要:

China is confronting aggravated ozone (O3) pollution, leading to adverse health impacts. This study quantifies the regional contributions to O3 in China using two approaches; estimating ① where goods are produced (the production method), and ② where goods are consumed (the consumption method). The production method predicts higher local source contribution than the consumption method; this difference can be attributed to exports. Occurrence of high-O3 episodes suggests a major contribution to O3 concentration as a result of trade activities. Based on the consumption method, 9219 out of 18 532 daily premature mortalities were caused by local sources in north China, while it increased to 14 471 of the production method when neglecting contributions due to export and consumption in other regions. This study suggests that O3 control should consider both where goods are consumed and emissions are emitted, especially taking account of international trade activities.

Sub-cytotoxic concentrations of ionic silver promote the proliferation of human keratinocytes by inducing

null

《医学前沿(英文)》 2018年 第12卷 第3期   页码 289-300 doi: 10.1007/s11684-017-0550-7

摘要:

Silver-containing preparations are widely used in the management of skin wounds, but the effects of silver ions on skin wound healing remain poorly understood. This study investigated the effects of silver ions (Ag+) on the proliferation of human skin keratinocytes (HaCaT) and the production of intracellular reactive oxygen species (ROS). After treating HaCaT cells with Ag+and/or the active oxygen scavenger N-acetyl cysteine (NAC), cell proliferation and intracellular ROS generation were assessed using CCK-8 reagent and DCFH-DA fluorescent probe, respectively. In addition, 5-bromo-2-deoxyUridine (BrdU) incorporation assays, cell cycle flow cytometry, and proliferating cell nuclear antigen (PCNA) immunocytochemistry were conducted to further evaluate the effects of sub-cytotoxic Ag+ concentrations on HaCaT cells. The proliferation of HaCaT cells was promoted in the presence of 106 and 105 mol/L Ag+ at 24, 48, and 72 h. Intracellular ROS generation also significantly increased for 5–60 min after exposure to Ag+. The number of BrdU-positive cells and the presence of PCNA in HaCaT cells increased 48 h after the addition of 106 and 105 mol/L Ag+, with 105 mol/L Ag+ markedly increasing the cell proliferation index. These effects of sub-cytotoxic Ag+ concentrations were repressed by 5 mmol/L NAC. Our results suggest that sub-cytotoxic Ag+ concentrations promote the proliferation of human keratinocytes and might be associated with a moderate increase in intracellular ROS levels. This study provides important experimental evidence for developing novel silver-based wound agents or dressings with few or no cytotoxicity.

关键词: ionic silver     human keratinocyte     cell proliferation     reactive oxygen species     active oxygen scavenger     NAC    

一种融合多特征聚类与神经网络的PM<sub>2.5sub>小时浓度预测新模型及其在中国城市的应用 Article

刘辉, 龙治豪, 段铸, 施惠鹏

《工程(英文)》 2020年 第6卷 第8期   页码 944-956 doi: 10.1016/j.eng.2020.05.009

摘要:

PM<sub>2.5sub>浓度预测对空气污染物早期预警具有重要意义。本文提出一种改进的PM<sub>2.5sub>浓度多步预测模型,即多特征聚类分解(MCD)-回声状态网络(ESN)-粒子群优化(PSO)混合模型。该模型包括分解预测部分和优化预测部分。在MCD方法中,采用RSAR算法选择重要的空气污染物变量,使用KC算法对所得变量进行聚类,利用EWT算法将PM<sub>2.5sub>浓度序列的聚类结果分解为多个子层。利用我国4个不同城市的真实PM<sub>2.5sub>浓度数据,验证了所提出模型的有效性。实验结果表明,所提出预测模型适用于PM<sub>2.5sub>浓度的多步高精度预测,具有比基准模型更优的预测性能。

关键词: PM<sub>2.5sub>2.5浓度预测     PM<sub>2.5sub>2.5浓度聚类     经验小波分解     多步预测    

Tribological mechanism of carbon group nanofluids on grinding interface under minimum quantity lubrication

《机械工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0733-z

摘要: Carbon group nanofluids can further improve the friction-reducing and anti-wear properties of minimum quantity lubrication (MQL). However, the formation mechanism of lubrication films generated by carbon group nanofluids on MQL grinding interfaces is not fully revealed due to lack of sufficient evidence. Here, molecular dynamic simulations for the abrasive grain/workpiece interface were conducted under nanofluid MQL, MQL, and dry grinding conditions. Three kinds of carbon group nanoparticles, i.e., nanodiamond (ND), carbon nanotube (CNT), and graphene nanosheet (GN), were taken as representative specimens. The [BMIM]BF4 ionic liquid was used as base fluid. The materials used as workpiece and abrasive grain were the single-crystal Ni–Fe–Cr series of Ni-based alloy and single-crystal cubic boron nitride (CBN), respectively. Tangential grinding force was used to evaluate the lubrication performance under the grinding conditions. The abrasive grain/workpiece contact states under the different grinding conditions were compared to reveal the formation mechanism of the lubrication film. Investigations showed the formation of a boundary lubrication film on the abrasive grain/workpiece interface under the MQL condition, with the ionic liquid molecules absorbing in the groove-like fractures on the grain wear’s flat face. The boundary lubrication film underwent a friction-reducing effect by reducing the abrasive grain/workpiece contact area. Under the nanofluid MQL condition, the carbon group nanoparticles further enhanced the tribological performance of the MQL technique that had benefited from their corresponding tribological behaviors on the abrasive grain/workpiece interface. The behaviors involved the rolling effect of ND, the rolling and sliding effects of CNT, and the interlayer shear effect of GN. Compared with the findings under the MQL condition, the tangential grinding forces could be further reduced by 8.5%, 12.0%, and 14.1% under the diamond, CNT, and graphene nanofluid MQL conditions, respectively.

关键词: grinding     minimum quantity lubrication     carbon group nanofluid     tribological mechanism    

Estimation of the minimum effective dose of tramadol for postoperative analgesia in infants using the

null

《医学前沿(英文)》 2012年 第6卷 第3期   页码 288-295 doi: 10.1007/s11684-012-0208-4

摘要:

Tramadol is a potent analgesic. However, the analgesia efficacy of tramadol, particularly its minimum effective dose (MED), is not clear. The aim of this study is to find MED of tramadol for postoperative analgesia in infants. The continual reassessment method (CRM) was performed to find MED. Infants undergoing surgeries were included in the 3 phases of this series. In each phase, 24 participants were allocated a different tramadol dose. Pain intensity was measured by face, legs, activity, cry, consolability (FLACC) measurement at 3-hour intervals. Tramadol was considered ineffective if the FLACC score was higher than 4 in 10 at anytime. In phase 1, seven dose levels were used within the range 0.1–0.4 mg?kg-1·h-1. Phase 1 was insufficient to identify the MED, and we increased the dose to 0.4–0.8 mg?kg-1·h-1 in phase 2. Phase 2 was insufficient to identify the MED. In phase 3, local anesthetic wound infiltration was introduced, and the tramadol dose levels tested were the same as in phase 1. The successful analgesia probability of tramadol 0.4 mg?kg-1?h-1 was 82.1% (95% CI, 0.742–0.925) in phase 1. In phase 2, it was 84.7% (95% CI, 0.789–0.991) with the dose 0.8 mg?kg-1?h-1. Phase 1 and phase 2 were insufficient to identify the MED. In phase 3, the successful analgesia probability for dose 0.35 mg?kg-1?h-1was 96.7% (95% CI, 0.853–0.997).We have demonstrated that tramadol provides insufficient analgesia for surgeries considered to cause moderate-to-severe postoperative pain in infants if used as the sole analgesic, and that local anesthetic wound infiltration enhances the efficacy of tramadol.

关键词: tramadol     minimum effective dose     postoperative analgesia     infants     continual reassessment method    

Vanadium and molybdenum concentrations in particulate from Palermo (Italy): analytical methods using

Diana AMORELLO,Santino ORECCHIO

《环境科学与工程前沿(英文)》 2015年 第9卷 第4期   页码 605-614 doi: 10.1007/s11783-014-0703-8

摘要: The main purpose of this work was to develop a reliable method for the determination of vanadium (V) and molybdenum (Mo) in atmosphere particles or aerosols because they can not be readily measured using conventional techniques. For this research, 30 particulate samples were collected from five different stations located at Palermo, Italy. We used the catalytic adsorptive stripping voltammetry and differential pulsed voltammetry to measure V and Mo in atmospheric particulate, respectively. The represented method includes advantages of high sensitivity, high selectivity, simplicity, reproducibility, speed and low costs. The quantification limits for V and Mo are, respectively, 0.57 and 0.80 ng·m . The precision, expressed as relative standard deviation (RSD %), was about 2% for both metals. The mean recoveries of added V and Mo were about 99.5% and ranged from 97% to 101%. Vanadium concentrations in particulate samples collected in Palermo area ranged from 0.57 to 7.7 ng·m , while Mo concentrations were in the range 0.8–51 ng·m . In many cases the concentrations of two elements in the particulate samples fall below the detection limits. The mean concentrations for V and Mo in particulate samples, collected in Palermo area, were respectively 3.1 and 5.9 ng·m .

关键词: vanadium     molybdenum     particulate     voltammetry     Palermo    

Cryogenic minimum quantity lubrication machining: from mechanism to application

《机械工程前沿(英文)》 2021年 第16卷 第4期   页码 649-697 doi: 10.1007/s11465-021-0654-2

摘要: Cutting fluid plays a cooling–lubrication role in the cutting of metal materials. However, the substantial usage of cutting fluid in traditional flood machining seriously pollutes the environment and threatens the health of workers. Environmental machining technologies, such as dry cutting, minimum quantity lubrication (MQL), and cryogenic cooling technology, have been used as substitute for flood machining. However, the insufficient cooling capacity of MQL with normal-temperature compressed gas and the lack of lubricating performance of cryogenic cooling technology limit their industrial application. The technical bottleneck of mechanical–thermal damage of difficult-to-cut materials in aerospace and other fields can be solved by combining cryogenic medium and MQL. The latest progress of cryogenic minimum quantity lubrication (CMQL) technology is reviewed in this paper, and the key scientific issues in the research achievements of CMQL are clarified. First, the application forms and process characteristics of CMQL devices in turning, milling, and grinding are systematically summarized from traditional settings to innovative design. Second, the cooling–lubrication mechanism of CMQL and its influence mechanism on material hardness, cutting force, tool wear, and workpiece surface quality in cutting are extensively revealed. The effects of CMQL are systematically analyzed based on its mechanism and application form. Results show that the application effect of CMQL is better than that of cryogenic technology or MQL alone. Finally, the prospect, which provides basis and support for engineering application and development of CMQL technology, is introduced considering the limitations of CMQL.

关键词: cryogenic minimum quantity lubrication (CMQL)     cryogenic medium     processing mode     device application     mechanism     application effect    

Impact and inhibitory mechanism of phenolic compounds on the formation of toxic Maillard reaction products

Jing TENG, Xiaoqian HU, Ningping TAO, Mingfu WANG

《农业科学与工程前沿(英文)》 2018年 第5卷 第3期   页码 321-329 doi: 10.15302/J-FASE-2017182

摘要:

As one of the dominant reactions occurring during thermal treatment of food, the Maillard reaction not only leads to the formation of aroma, browning color and taste compounds, but also contributes to the formation of some unpleasant toxic substances including acrylamide, heterocyclic amines and advanced glycation end products. Polyphenols, one of the most abundant antioxidants in the human diet, are contained in different kinds of foods. In this review, some recent studies on the impact of dietary polyphenols on the formation of acrylamide, heterocyclic amines and advanced glycation end products formed during the Maillard reaction are summarized, including the research work conducted with both chemical model systems and real food model systems; the possible inhibitory mechanisms of different polyphenols are also summarized and discussed in this review. Basically we found that some dietary polyphenols not only scavenge free radicals, but also react with reactive carbonyl species, thus lowering the formation of toxic Maillard reaction products. This review provides a useful theoretical foundation for the application of polyphenols in food safety, and suggests some directions for further study of natural products as inhibitors against the formation of toxic substances in thermally processed food.

关键词: advanced glycation end products     acrylamide     food safety     heterocyclic amine     Maillard reaction     polyphenols    

Mass concentrations and temporal profiles of PM

Liu YANG,Ye WU,Jiaqi LI,Shaojie SONG,Xuan ZHENG,Jiming HAO

《环境科学与工程前沿(英文)》 2015年 第9卷 第4期   页码 675-684 doi: 10.1007/s11783-014-0731-4

摘要: Mass concentrations of PM , PM and PM were measured near major roads in Beijing during six periods: summer and winter of 2001, winter of 2007, and periods before, during and after the 2008 Beijing Olympic Games. Since the control efforts for motor vehicles helped offset the increase of emissions from the rapid growth of vehicles, the averaged PM concentrations at roadsides during the sampling period between 2001 and 2008 fluctuated over a relatively small range. With the implementation of temporary traffic control measures during the Olympics, a clear “V” shaped curve showing the concentrations of particulate matter and other gaseous air pollutants at roadsides over time was identified. The average concentrations of PM , PM , CO and NO decreased by 31.2%, 46.3%, 32.3% and 35.4%, respectively, from June to August; this was followed by a rebound of all air pollutants in December 2008. Daily PM concentrations near major roads exceeded the National Ambient Air Quality Standard (Grade II) for 61.2% of the days in the non-Olympic periods, while only for 12.5% during the Olympics. The mean ratio of PM /PM near major roads remained relatively stable at 0.55 (±0.108) on non-Olympic days. The ratio decreased to 0.48 (±0.099) during the Olympics due to a greater decline in fine particles than in coarse-mode PM. The ratios PM /PM fluctuated over a wide range and were statistically different from each other during the sampling periods. The average ratios of PM /PM on non-Olympic days were 0.71.

关键词: particulate matter     traffic     control measure     Beijing Olympic Games    

Design of a cyclic inhibitory CPG controller for the locomotion of a snakelike robot

LU Zhen-li, MA Shu-gen, LI Bin, WANG Yue-chao

《机械工程前沿(英文)》 2006年 第1卷 第4期   页码 396-402 doi: 10.1007/s11465-006-0046-7

摘要: The rhythmic locomotion of a creature is a self-excitation behavior of the CPG (central pattern generator), which makes it supremely adapted for environment. Based on this fact, firstly, a snake-ike robot controller with cyclic inhibitory CPG model was designed, and then the stability of a single neuron, CPG model and the NON ( neuron oscillator network) was analyzed. By implementing this control architecture to a simulator based on the mechanical dynamics of a real snake-like robot named Perambulator-I, we presented preliminary rules for parameter setting of the CPG controller to modulate the number of S shapes, the curve of the body shape, locomotion velocity, and the curve of the locomotion trajectory for serpentine locomotion. Moreover, we demonstrated that Perambulator-I can successfully exhibit serpentine locomotion by using the output of the proposed CPG controller. The results of this paper provide a realistic approach for designing an artificial CPG controller.

Finite element analysis of stress concentrations and failure criteria in composite plates with circular

null

《机械工程前沿(英文)》 2014年 第9卷 第3期   页码 281-294 doi: 10.1007/s11465-014-0307-9

摘要:

In this study, the stress concentration factors (SCF) in cross-and-angle-ply laminated composite plates as well as in isotropic plates with single circular holes subjected to uniaxial loading is studied. A quadrilateral finite element of four-node with 32 degrees of freedom at each node, previously developed for the bending and mechanical buckling of laminated composite plates, is used to evaluate the stress distribution in laminated composite plates with central circular holes. Based up on the classical plate theory, the present finite element is a combination of a linear isoparametric membrane element and a high precision rectangular Hermitian element. The numerical results obtained by the present element compare favorably with those obtained by the analytic approaches published in literature. It is observed that the obtained results are very close to the reference results, which demonstrates the accuracy of the present element. Additionally, to determine the first ply failure (FPF) of laminated plate, several failure criterions are employed. Finally, to show the effect of ratio on the failure of plates, a number of figures are given for different fiber orientation angles.

关键词: laminated composite plates     stress concentration     geometric singularity     anisotropic effect    

Design, synthesis and HIV-RT inhibitory activity of novel thiazolidin-4-one derivatives

Hua CHEN, Zaihong GUO, Qingmei YIN, Xiaoxu DUAN, Yunjing GU, Xiaoliu LI

《化学科学与工程前沿(英文)》 2011年 第5卷 第2期   页码 231-237 doi: 10.1007/s11705-010-1022-7

摘要: A series of 2-aryl-3-(4,5,6-trimethylpyrimidin-2-yl) thiazolidin-4-ones ( – ) and their derivatives bearing a lipophilic substituent, like acetoxy group ( – ), propionyloxy group ( – ), methyl ( and ) at C-5 on thiazolidin-4-one ring were designed, synthesized and evaluated for their HIV-RT inhibitory activity. Using self-catalyzed Pummerer reaction, compounds – and – were obtained in good yield (63.1% 75.2%). Preliminary anti-HIV-RT test of these derivatives indicated that compounds – , (propionyloxy group at C-5) showed moderate HIV-RT inhibitory activity and compounds and with methyl at C-5 showed a weak HIV-RT inhibitory activity. Structure activity relationship analysis suggested that the substituted groups on C-5 would be unfavorable to anti-HIV-RT activity and that the steric effect might play a critical role in the anti-HIV RT activity.

关键词: 5-subsituted thiazolidin-4-ones     Pummerer reaction     anti-HIV-RT activity     SARs    

Modeling of the minimum cutting thickness in micro cutting with consideration of the friction around

Tianfeng ZHOU, Ying WANG, Benshuai RUAN, Zhiqiang LIANG, Xibin WANG

《机械工程前沿(英文)》 2020年 第15卷 第1期   页码 81-88 doi: 10.1007/s11465-019-0561-y

摘要: Friction modeling between the tool and the workpiece plays an important role in predicting the minimum cutting thickness during TC4 micro machining and finite element method (FEM) cutting simulation. In this study, a new three-region friction modeling is proposed to illustrate the material flow mechanism around the friction zone in micro cutting; estimate the stress distributions on the rake, edge, and clearance faces of the tool; and predict the stagnation point location and the minimum cutting thickness. The friction modeling is established by determining the distribution of normal and shear stress. Then, it is applied to calculate the stagnation point location on the edge face and predict the minimum cutting thickness. The stagnation point and the minimum cutting thickness are also observed and illustrated in the FEM simulation. Micro cutting experiments are conducted to validate the accuracy of the friction and the minimum cutting thickness modeling. Comparison results show that the proposed friction model illustrates the relationship between the normal and sheer stress on the tool surface, thereby validating the modeling method of the minimum cutting thickness in micro cutting.

关键词: tool friction     minimum cutting thickness     finite element method     tool edge radius     micro cutting    

Achieving air pollutant emission reduction targets with minimum abatement costs: An enterprise-level

《环境科学与工程前沿(英文)》 2022年 第16卷 第2期 doi: 10.1007/s11783-021-1459-6

摘要:

• Quantification of efficiency and fairness of abatement allocation are optimized.

关键词: Pollutant emission reduction allocation     Emission reduction measures     Total abatement cost     Economic efficiency     Abatement space    

标题 作者 时间 类型 操作

Influences and mechanisms of nanofullerene on the horizontal transfer of plasmid-encoded antibiotic resistance genes between

Qingkun Ji, Caihong Zhang, Dan Li

期刊论文

基于消费端的源解析表明不同区域对O<sub>3sub>浓度和健康效应的贡献

Shengqiang Zhu, Peng Wang, Siyu Wang, Guannan Geng, Hongyan Zhao, Yuan Wang, Hongliang Zhang

期刊论文

Sub-cytotoxic concentrations of ionic silver promote the proliferation of human keratinocytes by inducing

null

期刊论文

一种融合多特征聚类与神经网络的PM<sub>2.5sub>小时浓度预测新模型及其在中国城市的应用

刘辉, 龙治豪, 段铸, 施惠鹏

期刊论文

Tribological mechanism of carbon group nanofluids on grinding interface under minimum quantity lubrication

期刊论文

Estimation of the minimum effective dose of tramadol for postoperative analgesia in infants using the

null

期刊论文

Vanadium and molybdenum concentrations in particulate from Palermo (Italy): analytical methods using

Diana AMORELLO,Santino ORECCHIO

期刊论文

Cryogenic minimum quantity lubrication machining: from mechanism to application

期刊论文

Impact and inhibitory mechanism of phenolic compounds on the formation of toxic Maillard reaction products

Jing TENG, Xiaoqian HU, Ningping TAO, Mingfu WANG

期刊论文

Mass concentrations and temporal profiles of PM

Liu YANG,Ye WU,Jiaqi LI,Shaojie SONG,Xuan ZHENG,Jiming HAO

期刊论文

Design of a cyclic inhibitory CPG controller for the locomotion of a snakelike robot

LU Zhen-li, MA Shu-gen, LI Bin, WANG Yue-chao

期刊论文

Finite element analysis of stress concentrations and failure criteria in composite plates with circular

null

期刊论文

Design, synthesis and HIV-RT inhibitory activity of novel thiazolidin-4-one derivatives

Hua CHEN, Zaihong GUO, Qingmei YIN, Xiaoxu DUAN, Yunjing GU, Xiaoliu LI

期刊论文

Modeling of the minimum cutting thickness in micro cutting with consideration of the friction around

Tianfeng ZHOU, Ying WANG, Benshuai RUAN, Zhiqiang LIANG, Xibin WANG

期刊论文

Achieving air pollutant emission reduction targets with minimum abatement costs: An enterprise-level

期刊论文