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Effect of fluid motion on colony formation in Microcystis aeruginosa

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Water Science and Engineering 2013年第1期6卷 106-116页

作者： lin li wei zhu Ting-ting wang Yong-gang LUO Feng-lan CHEN xiao TAN College of Environment Hohai University School of Geography and Environment Jiangxi Normal University National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety Hohai University Zhenjiang Academy of Urban Planning and Design

Microcystis aeruginosa, generally occurring in large colonies under natural conditions, mainly exists as single cells in laboratory cultures. The mechanisms involved in colony formation in Microcystis aeruginosa and their roles in algal blooms remain unknown. In this study, based on previous research findings that fluid motion may stimulate the colony formation in green algae, cul^are experiments were conducted under axenic conditions in a circular water chamber where the flow rate, temperature, light, and nutrients were controlled. The number of cells of Microcystis aeruginosa, the number of cells per colony, and the colonial characteristics in various growth phases were observed and measured. The results indicated that the colony formation in Microcystis aeruginosa, which was not observed under stagnant conditions, was evident when there was fluid motion, with the number of cells per largest colony reaching 120 and the proportion of the number of cells in colonial form to the total number of cells and the mean number of cells per colony reaching their peak values at a flow rate of 35 crn/s. Based on the analysis of colony formation process, fluid motion stimulates the colony formation in Microcystis aeruginosa in the lag growth phase, while flushes and disaggregates the colonies in the exponential growth phase. The stimulation effect in the lag growth phase may be attributable to the involvement of fluid motion in a series of physiological processes, including the uptake of trace elements and the synthesis and secretion of polysaccharides. In addition, the experimental groups exhibiting typical colonial characteristics in the lag growth phase were found to have higher cell biomass in the later phase.

关键词： Microcystis aeruginosa colony formation," fluid motion flushing effect," viscousshear extracellular polysaccharide

Possible mechanisms of lycopene amelioration of learning and memory impairment in rats with vascular dementia

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Neural Regeneration Research 2020年第2期15卷 332-341页

作者： Ning-wei zhu xiao-lan Yin Ren lin xiao-lan Fan Shi-jie Chen Yuan-Ming zhu xiao-Zhen Zhao Department of Human Anatomy Histology and EmbryologySchool of Basic Medical SciencesFujian Medical UniversityFuzhouFujian ProvinceChina Department of Pharmacy Zhejiang Pharmaceutical CollegeNingboZhejiang ProvinceChina Key Laboratory of Brain Aging and Neurodegenerative Diseases School of Basic Medical SciencesFujian Medical UniversityFuzhouFujian ProvinceChina

Oxidative stress is involved in the pathogenesis of vascular dementia. Studies have shown that lycopene can significantly inhibit oxidative stress;therefore, we hypothesized that lycopene can reduce the level of oxidative stress in vascular dementia. A vascular dementia model was established by permanent bilateral ligation of common carotid arteries. The dosage groups were treated with lycopene(50, 100 and 200 mg/kg) every other day for 2 months. Rats without bilateral carotid artery ligation were prepared as a sham group. To test the ability of learning and memory, the Morris water maze was used to detect the average escape latency and the change of search strategy. Hematoxylin-eosin staining was used to observe changes of hippocampal neurons. The levels of oxidative stress factors, superoxide dismutase and malondialdehyde, were measured in the hippocampus by biochemical detection. The levels of reactive oxygen species in the hippocampus were observed by dihydroethidium staining. The distribution and expression of oxidative stress related protein, neuron-restrictive silencer factor, in hippocampal neurons were detected by immunofluorescence histochemistry and western blot assays. After 2 months of drug administration,(1) in the model group, the average escape latency was longer than that of the sham group, and the proportion of straight and tend tactics was lower than that of the sham group, and the hippocampal neurons were irregularly arranged and the cytoplasm was hyperchromatic.(2) The levels of reactive oxygen species and malondialdehyde in the hippocampus of the model group rats were increased, and the activity of superoxide dismutase was decreased.(3) Lycopene(50, 100 and 200 mg/kg) intervention improved the above changes, and the lycopene 100 mg/kg group showed the most significant improvement effect.(4) Neuron-restrictive silencer factor expression in the hippocampus was lower in the sham group and the lycopene 100 mg/kg group than in the model group.(5) Th

关键词： bilateral carotid artery ligation lycopene hippocampus learning and memory malondialdehyde neuron neuron-restrictive silencer factor reactive oxygen species superoxide dismutase

Micro-macro fracture mechanism of heterogeneous granite in percussive drilling

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Petroleum Science 2023年第5期20卷 3131-3142页

作者： wei-ji liu Yan-Fei wang Zhao-wang Dan xiao-Hua zhu School of Mechatronic Engineering Southwest Petroleum UniversityChengdu610500SichuanChina Geothermal Energy Research Center Southwest Petroleum UniversityChengdu610500SichuanChina Powerchina Sinohydro Bureau 7 Co. LTDChengdu610500SichuanChina

The conventional rotary rock breaking method faces a technical bottleneck in improving the rate of penetration(ROP)in deep hard *** drilling is the most potential approach to increase rock-breaking efficiency and ***,the rock-breaking mechanism of percussive drilling is still unclear enough,especially the micro-fracture mechanism of rock under confining pressure(under lateral pressure and hydraulic pressure).In this paper,the impact rock breaking experiments by four kinds of Polycrystalline Diamond Compact(PDC)cutters are carried out using a drop-weight impact testing machine and an acoustic emission(AE)recording system,the influence of parameters such as cutter shape,rake angle,and impact energy on rock-breaking are systematically *** study includes a numerical simulation to examine the process of crack initiation,propagation,and cuttings formation during the impact process with the consideration of confining *** results show the conicalshaped cutter is the most aggressive with high breaking *** penetration depth of the cutter is mainly influenced by the impact energy and cutter shape than the rake angle of the *** exists critical impact energy makes the rock breaking efficiency the *** critical impact energy is about 40 J when using the conical-shaped cutter with a rake angle of 15°.The rock mainly failed in tensile mode,and the inter-grain crack is the main *** pressure can inhibit the formation of horizontal cracks,while lateral pressure can inhibit the formation of vertical cracks and reduce the proportion of tensile *** research results can provide some reference and basis for improving the rock-breaking efficiency in deep hard formations.

关键词： Percussive drilling PFC Rock fragmentation characteristics Rock breaking efficiency

Subsurface macro-inclusions and solidified hook character in aluminum-killed deep-drawing steel slabs

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International Journal of Minerals,Metallurgy and Materials 2014年第6期21卷 531-543页

作者： xiao-xuan Deng lin-ping li Xin-hua wang Yun-qing ji Chen-xi ji Guo-sen zhu School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Shougang Research Institute of Technology Shougang Group

Subsurface macro-inclusions and hooks are detrimental to the surface quality of deep-drawing steel sheets. However, little is known about the relationship between macro-inclusions and hooks. Thus, in this work, two ultralow carbon （ULC） steel slabs and two low carbon （LC） aluminum-killed steel slabs were sampled to study the relationship between hooks and subsurface macro-inclusions, which were detected on the cross-sections of steel samples with an area of 56058 mm2 using an automated scanning electron microscopy/energy-disper-sive X-ray spectroscopy system. Results show that subsurface inclusions larger than 200 μm were almost entrapped by hook structures, whereas the location of other inclusions smaller than 200μm had no obvious dependence on the location of solidified hooks. Furthermore, the number density （ND） of subsurface inclusions larger than 200μm decreased from 0.02 to 0 cm-2 in ULC steel as the mean hook depth decreased from 1.57 to 1.01 mm. Similar trends were also observed in LC steel. In addition, the detected inclusions larger than 200μm were concentrated in the region near the slab center （3/8 width-5/8 width）, where hook depths were also larger than those at any other locations. Therefore, minimizing the hook depth is an effective way to reduce inclusion-induced sliver defects in deep-drawing steels.

关键词： low carbon steel aluminum-killed steel steel sheet deep drawing inclusions hooks

Long-term Thermo-oxidative Degradation Modeling of a Carbon Fiber Reinforced Polyimide Composite:Multistep Degradation Behaviors and Kinetics

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Chinese Journal of Polymer Science 2020年第11期38卷 1202-1213,I0007页

作者： Yi liu xiao-Zhou Xu Song Mo Bang-wei lan Cai-Zhen zhu Cui-Hua li jian Xu lin Fan Institute of Low-dimensional Materials Genome Initiative College of Chemistry and Environmental EngineeringShenzhen UniversityShenzhen 518060China Laboratory of Advanced Polymer Materials Institute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049China

This study aims to disclose the thermo-oxidative degradation behaviors and kinetics of a carbon fiber reinforced polyimide(CFRPI)composite for modeling of the Iong-term degradation *** degradation behaviors were revealed through off-gas products analysis,and the overall kinetic interpretation was achieved from study of the mass-loss curves recorded under dynamic *** was found that thermooxidative degradati on of the CFRPI composite was a multistep process,which in eluded four main reaction *** most kinetic an alysis methods were derived from simple reactions described by a single kinetic triplet,they cannot be applied reliably to such a ***,we firstly separated the four overlapped reaction steps by peak fitting of derivative thermogravimetric curves using Fraser-Suzuki equation consider!ng the asymmetrical n ature of kin etic curves,and subsequently an a lyzed each in dividual reaction employing Friedma n method and experimental master-plots *** sets of kinetic triplets were determined to characterize the entire degradation *** validity of four corresponding kinetic triplets was confirmed by perfect simulation of mass-loss curves recorded at both dynamic conditions used in kinetic analysis and entirely different isothermal ***,modeling of Iong-term aging at 400°C of the CFRPI composite was successfully achieved based on these kinetic *** predicted mass loss and flexural property correlated well with experimental *** study can serve as a basis for rapid evaluation of the long-term durability of the CFRPI composite in various application environments.

关键词： Polyimide composite Thermo-oxidative degradation Multistep process Kinetics Long-term aging modeling

An intelligent electronic capsule system for automated detection of gastrointestinal bleeding

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2010年第12期11卷 937-943页

作者： Hong-ying liU Gang wang Kang wei Xi-tian PI lan zhu xiao-lin ZHENG Zhi-yu WEN Key Laboratory of Biorheological Science and Technology of Ministry of Education College of Bioengineering Chongqing University Chongqing 400030 China Key Laboratories for National Defense Science and Technology of Innovative Micro-Nano Devices and System Technology Chongqing University Chongqing 400030 China

In clinical practice,examination of the hemorrhagic spot (HS) remains *** this paper,we describe a remote controlled capsule (RCC) micro-system with an automated,color-based sensor to identify and localize the HS of the gastrointestinal (GI) *** vitro testing of the detecting sensor demonstrated that it was capable of discriminating mimetic intestinal fluid (MIF) with and without the hemoglobin (Hb) when the concentration of Hb in MIF was above 0.05 g/***,this RCC system is able to detect the relatively accurate location of the HS in the GI tract.

关键词： Smart capsule Intestinal bleeding Color sensor Biomedical micro-electromechanical system (BioMEMS)

Poly(3-hexylthio) thiophene Field-effect Transistor Device Performance: Impact of the Content of Hexylthio Side Chain on Backbone

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Chinese Journal of Polymer Science 2024年第1期42卷 14-23,I0005页

作者： Hao-Yu liu lian-He Han ling-wei Kong li-Ping zhu xiao-lan Qiao Mei-Fang zhu State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and EngineeringDonghua UniversityShanghai 201620China School of Electronic Information and Electrical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Regioregular poly(3-hexylthio)thiopene(P3HTT) has emerged tremendous potential in organic electronic applications due to the strong noncovalent interactions from the sulfur atom linked to thiophene. However, P3HTT generally exhibits low charge mobility mostly due to poor solution processability attributed to dense arrangement of hexylthio side chain in polymer, which led to strong noncovalent interactions among sulfur atoms. To balance the nonvalent interaction and aggregation for P3HTT, herein, we systematically study the effect of hexylthio side chain content in polymer backbone on the structure and properties. A series of regioregular P3HTT-based homopolymers(P3HTT, P3HTT-50,P3HTT-33 and P3HTT-25) were prepared via Kumada catalyst transfer polycondensation method from a set of mono-, bi-, ter-and quarterthiophenes containing different contents of hexylthio side chain. The DFT calculation shows the planarity of polymers backbone could be improved through reducing the density of hexylthio side chain in polymer mainchain. And significant changes in their crystallinity, aggregation and optical properties were observed with the content of hexylthio side chain reducing. The P3HTT-33 displayed the highest field-effect transistor hole mobility of 2.83×10^(-2) cm^(2)·V^(-1)·s^(-1) resulting from a balance between the crystallinity and planarity. This study demonstrates modulating the content of hexylthio side chain in P3HTT is an effective strategy to optimize the opto-electronic properties of polymer obtaining excellent semiconductor device performance.

关键词： Conjugated polymer Polythiophene Noncovalent interaction Molecular aggregation Organic field-effect transistor

Flow characteristics of silicon oil in nanochannels

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Journal of Hydrodynamics 2021年第6期33卷 1282-1290页

作者： Yong wang Fu-quan Song Kai ji Ye-heng Sun wei-yao zhu xiao-hong wang School of Engineering Science University of Science and Technology of ChinaHefei 230026China School of Petrochemical and Energy Engineering Zhejiang Ocean UniversityZhoushan 316022China Exploration and development scientific research institute of Shengli oil field branch of Sinopec Dongying 257015China Civil and Resource Engineering School University of Science and Technology BeijingBeijing 100083China

The nonlinear flow of liquids through nanoscale channels play an important role in the separation and purification properties of porous membranes,the manufacture of biofilm ionic channels and microfluidic chips,the production of micro electro-mechanical *** oil flow experiments were conducted through anodic alumina films with pore sizes of 26,67,89,and 124 nm,in which flow mechanism and characteristics of the oil through the nanoscale channels were *** nanoflow features are revealed:(1)The experimental flow rate is less than the theoretical flow rate through nanochannels,as solid-liquid interaction increasing flow resistance.(2)At small shear rate,the boundary layer is one,indicating existence of a threshold pressure of oil flow through nanochannels.(3)The boundary layer decreases with the increasing of shear rate,and it rapidly decreases as shear rate increases when the value of shear rate is small.(4)The drag coefficient decreases nonlinearly with increasing shear rate,decreasing more slowly when value of shear rate is big,and trending towards 1 in the case of large shear *** is shown that the non-linearity of flow is induced by great solid-liquid interaction in nano and microscale,and increasing the driving force can raise the efficiency at the nanometer scale.

关键词： Nano and microflow nanofluid threshold pressure the boundary layer tight reservoir

Air pollution and meteorological conditions significantly contribute to the worsening of allergic conjunctivitis:a regional 20-city,5-year study in Northeast China

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light(Science & Applications) 2021年第11期10卷 2128-2142页

作者： Cheng-wei Lu jing Fu Xiu-Fen liu wei-wei Chen ji-Long Hao xiao-lan li Om Prakash Pant The Department of Ophthalmology The First Hospital of Jilin UniversityChangchun130021China Key Laboratory of Wetland Ecology and Environment Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun130102China Institute of Atmospheric Environment China Meteorological AdministrationShenyang110166China Dhangadhi Netralaya Eye Hospital Dhangadhi3KailaliNepal

This study is the first to explore the potential associations among allergic conjunctivitis(AC),air pollution,and meteorological conditions in Northeast *** of meteorology,ambient atmospheric pollutants,and the incidence of allergic conjunctivitis(IAC)in prefecture-level cities between the years 2014 and 2018 are *** results show an increasing trend in the AC of average growth rate per annum 7.6%,with the highest incidence in the provincial *** IAC is positively correlated with atmospheric pollutants(i.e.,PM_(2.5),PM_(10),CO,SO_(2),NO_(2),and O_(3))and meteorological factors(i.e.,air temperature and wind speed),but negatively correlated with relative *** results suggest that the IAC is directly proportional to pollution level and climatic conditions,and also the precedence of air *** have further obtained the threshold values of atmospheric pollutants concentration and meteorological factors,a turning point above which more AC may be *** with the air quality standard advised by China and the World Health Organization(WHO),both thresholds of PM_(10)(70μg m^(-3))and PM_(2.5)(45μg m^(-3))are higher than current standards and pose a less environmental risk for the ***_(2) threshold(23μg m^(-3))is comparable to the WHO standard and significantly lower than that of China’s,indicating greater environmental risks in *** thresholds of NO_(2)(27μg m^(-3))and O_(3)(88μg m^(-3))are below current standards,indicating that they are major environmental risk factors for the *** findings highlight the importance of atmospheric environmental protection and reference for health-based amendment.

关键词： allergic meteorological pollution