The multi-orifice plate gas sparger, mainly composed of a multi-orifice plate and a gas chamber, is one of the most common sparger facilities.The aeration performance of multi-orifice plate has a close relation with t...The multi-orifice plate gas sparger, mainly composed of a multi-orifice plate and a gas chamber, is one of the most common sparger facilities.The aeration performance of multi-orifice plate has a close relation with the multiorifice plate configuration.In addition, the weeping phenomenon has a considerable influence on the gas chamber condition which affects the bubble detachment volume directly.This paper conducts a set of visual experiments to study the influence of multi-orifice configuration and gas chamber condition on the aeration performance of gas sparger.For multi-orifice plate, an improved theoretical model is proposed which considers the wave effect of the previous bubbles generated from adjacent orifices and the variance of the number of active bubbling orifice.A parameter is proposed to evaluate the aeration performance in order to overcome the difficulty caused by the randomness of bubble formation process.The experimental results suggest that the gas chamber filled with water is in favor of large bubble formation.The influence of the pitch of orifice on aeration performance can only be observed in high-restricted case.According to the theoretical model and experimental results, the influences of gas flow rate and the number of open orifices on the aeration performance are analyzed and a design criterion for the number of open orifice is proposed.展开更多
Pico-and nano-eukaryotic plankton are important members of marine ecosystems.To understand their community structure and spatio-temporal variations in the Beibu Gulf,and to study the impact of Changjiang Nuclear Power...Pico-and nano-eukaryotic plankton are important members of marine ecosystems.To understand their community structure and spatio-temporal variations in the Beibu Gulf,and to study the impact of Changjiang Nuclear Power Plant(CNPP)located in the northwest coast of the Hainan Island on the eukaryotic plankton,we studied these issues in the coastal water near CNPP bimonthly from February 2018 to January 2019 via 18 S Illumina sequencing.The results reveal a higher genetic alphadiversity and less beta-diversity of the plankton community in small-size(0.45-5μm and 5-20μm)fractions than in large-size(20-200μm and>20μm)fractions.The small-sized phytoplankton,including Micromonas(Chlorophyta)and Minutocellus(Bacillariophyta),as well as heterotrophic plankton,including Paraphysomonas(Chrysophyceae),Ellobiopsis(Dinoflagellates),and Syndiniales(Dinoflagellates),took up a considerable proportion in eukaryotic plankton community.In addition,it showed a slight temperature increase and no significant difference in eukaryotic plankton community between the outfall of CNPP and other sampling sites,suggesting that the impact of the thermal discharge from the CNPP on local eukaryotic plankton community was limited.展开更多
Bubble coalescence reduces specific area and weakens the work performance of bubble column. The bubble coalescence near gas sparger which is caused mainly by bubble growing is different from the ones occurring in majo...Bubble coalescence reduces specific area and weakens the work performance of bubble column. The bubble coalescence near gas sparger which is caused mainly by bubble growing is different from the ones occurring in major liquid. Bubble coalescence efficiency near gas sparger is influenced by many factors including sparger configuration, gas flow rate, bubble deformation, solution composition, etc. This work has conducted a set of visual experiments to study the coalescence characteristics near multi-orifice plate. The experiment parameters cover a wide range of conditions including large scope of gas flow rate,different kinds of solution and orifice configurations. The experimental results suggest that coalescence time is applicable to reflect the influence of the pitch of orifices and gas flow rate on bubble coalescence efficiency. As the number of orifices increases, bubble coalescence efficiency is reduced by the disturbance from the bubbles at adjacent orifices. A hindering coefficient is used to consider the hindering effect of additives on bubble coalescence efficiency. Finally a new calculation expression is established to predict bubble coalescence efficiency near multi-orifice plate whose fundamental form is based on the logistic curve of binary response. The calculated values that refer to this calculation expression are well consistent with the experimental results.展开更多
Amphidinium species are amongst the most abundant benthic dinoflagellates in marine intertidal sandy ecosystems.Some of them are able to produce a variety of bioactive compounds that can have both harmful effects and ...Amphidinium species are amongst the most abundant benthic dinoflagellates in marine intertidal sandy ecosystems.Some of them are able to produce a variety of bioactive compounds that can have both harmful effects and pharmaceutical potentials.The diversity of Amphidinium in shallow waters along the Chinese coast was investigated by isolating single cells from sand,coral,and macroalgal samples collected from 2012 to 2020.Their morphologies were subjected to examination using light microscopy(LM)and scanning electron microscopy(SEM).A total of 74 Amphidinium strains were morphologically identified,belonging to 11 species:A.carterae,A.gibbosum,A.operculatum,A.massartii,A.cf.massartii,A.fijiensis,A.pseudomassartii,A.steinii,A.thermaeum,A.theodori,A.tomasii,as well as an undefined species.The last seven species have not been previously reported in Chinese waters.Amphidinium carterae subcladesⅠ,Ⅱ,andⅣwere found in the South China Sea,while subcladeⅢwas only found in the Yellow Sea.Threadlike body scales were observed on the surface of subcladesⅢ and Ⅳ,supporting the idea that A.carterae might contain several different species.Large subunit ribosomal RNA(LSU rRNA)sequencesbased phylogeny revealed two groups(GroupsⅠandⅡ)within Amphidinium,which is consistent with the relative position of sulcus(in touch with cingulum or not).In addition,large differences in morphology and molecular phylogeny between A.operculatum(the type species of Amphidinium)and other species,suggest that a subdivision of Amphidinium might be needed.The pigment profiles of all available strains were analyzed by high performance liquid chromatography(HPLC).Eleven pigments,including peridinin,diadinoxanthin,diatoxanthin,pheophorbide(and pheophorbide a),antheraxanthin,β-carotene,and four different chlorophylls were detected.The high pheophorbide/pheophorbide a ratio in Amphidinium implies that it may be a good candidate as a natural source of photosensitizers,a well-known anticancer drug.展开更多
Weeping is an adverse phenomenon which results in higher pressure drop and poorer aeration performance.Visual experiments have been conducted to study the mechanism by which weeping impairs the work performance of mul...Weeping is an adverse phenomenon which results in higher pressure drop and poorer aeration performance.Visual experiments have been conducted to study the mechanism by which weeping impairs the work performance of multi-orifice plate.A theoretical model is improved to analyze the weeping phenomenon of multiorifice plate based on potential flow theory.The relations of different bubbling conditions and weeping rate are analyzed.Weeping condition and average weeping rate have relation with the driven pressure differential and dynamic variation of gas chamber pressure.In addition,a set of experiments are designed to study the influence of various factors on weeping rate.The bubble coalescence during bubble formation is a fatal factor determining weeping rate,so the relation between weeping rate and gas flow rate is concerned with the pitch of orifices and orifice diameter.There is a critical plate thickness which is in favor of weeping.展开更多
The dinoflagellate cyst assemblages on the Nanji Island in the East China Sea, are documented at the first time to construct a quantitative overview of the cyst bank from 2014 to 2015. Thirty-four morphotypes from six...The dinoflagellate cyst assemblages on the Nanji Island in the East China Sea, are documented at the first time to construct a quantitative overview of the cyst bank from 2014 to 2015. Thirty-four morphotypes from six groups are identified and quantified at eight sampling sites around the island, including a high proportion of potentially toxigenic species(14%). Autotrophic dinocysts constitute 74% of the total cyst counts, which is relatively low(two to thirty-three per millilitre sediment) compared with previous studies in adjacent areas. Scrippsiella trochoidea and Protoperidinium avellana are the most abundant autotrophic and heterotrophic species, respectively. A multivariate analysis is performed to assess associations between dinocysts and abiotic or biotic variables.Differentiation among seasons is evident in the detrended correspondence analysis(DCA) ordination plot, while a spatial pattern is not clearly revealed despite heterogeneity of the hydrodynamic conditions between sampling sites. Soluble reactive phosphate, the ratio of nitrogen to phosphorus concentrations and Karenia mikimotoi bloom are the three factors significantly(P<0.05) related to surface sediment cyst assemblage defined by the canonical correspondence analysis(CCA), highlighting the importance of nutrient regime to a dinocyst distribution in this area. Although attempts to address the origin of HAB events in recent years using seed banks have failed, knowledge can be valuable for further investigation of dinocyst dynamics and potential toxin threats on the Nanji Island.展开更多
The lupane-type triterpenoids are endowed with a wide range of biological activities such as antiviral, anti-inflammatory and anticancer activity. We describe here its potential application in Alzheimer＇s disease （A...The lupane-type triterpenoids are endowed with a wide range of biological activities such as antiviral, anti-inflammatory and anticancer activity. We describe here its potential application in Alzheimer＇s disease （AD） treatment as an inhibitor of PS1/BACE1 interaction. 3-a-Akebonoic acid, which emanated from a high throughput screening （HTS）, was discovered to interfere with P S 1/BACE 1 interaction and reduce amyloid β-protein （Aβ） production. In view of the limited source, we instead used naturally rich betulinic acid （compound 2） as starting material for lead optimization and a focused library of its derivatives was constructed to gain a better understanding of the structure activity relationship （SAR） of triterpenoid-type inhibitor of PS1/BACE1 interaction. Compound 22 was finally chosen as the most potent PS 1/BACE 1 interaction inhibitor, which reduced Aβgeneration effectively.展开更多
The revolutionary induced pturipotent stem celt （iPSC） technoLogy provides a new means for celt replacement therapies and drug screening. Small molecule compounds have been found extremely useful to improve the gene...The revolutionary induced pturipotent stem celt （iPSC） technoLogy provides a new means for celt replacement therapies and drug screening. Small molecule compounds have been found extremely useful to improve the generation of iPSCs and understand the repro- gramming mechanism. Here we report the identification of a novel chemical, CYT296, which improves OSKM-mediated induction of iPSCs for 〉10 folds and enables efficient reprogramming with only Oct4 in combination with other small molecules. The derived iPSCs are genuinely pluripotent and support the development oftwo ＇All-iPSC＇ mice by tetraploid complementation. CYT296 profoundly impacts heterochromatin formation without affecting celt viability. MEFs treated with CYT296 exhibit de-condensed chromatin structure with markedly reduced loci containing heterochromatin protein 1α （HPIoL） and H3K9me3, which is very similar to the chromatin configuration in embryonic stem cells （ESCs）. Given that an open chromatin structure serves as a hallmark of pLuripotency and has to be acquired to fulfill reprogramming, we propose that CYT296 might facilitate this process by disrupting condensed chromatin, thereby creating a more favorable environment for reprogramming. In agreement of this idea, shRNA targeting HP1α also promotes the generation of iPSCs. Thus current findings not only provide a novel chemical for efficient iPSC induction, but also suggest a new approach to regulate somatic cell reprogramming by targeting chromatin de-condensation with small molecules.展开更多
The scatter-hoarding behavior of granivorous rodents plays an important role in seed dispersal and seedling regeneration of trees,as well as the evolution of several well-known mutualisms between trees and roden...The scatter-hoarding behavior of granivorous rodents plays an important role in seed dispersal and seedling regeneration of trees,as well as the evolution of several well-known mutualisms between trees and rodents in forest ecosystems.Because it is difficult to identify seed hoarders and pilferers under field conditions by traditional methods,the full costs incurred and benefits accrued by scatter-hoarding have not been fully evaluated in most systems.By using infrared radiation camera tracking and seed tagging,we investigated the benefits and losses of scatter-hoarded seeds(Camellia oleifera)for 3 sympatric rodent species(Apodemus draco,Niviventer confucianus and Leopoldamys edwardsi)in a subtropical forest of Southwest China during 2013 to 2015.We established the relationships between the rodents and the seeds at the individual level.For each rodent species,we calculated the cache recovery rate of cache owners,as well as conspecific and interspecific pilferage rates.We found that all 3 sympatric rodent species had a cache recovery advantage with rates that far exceeded average pilferage rates over a 30-day tracking period.The smallest species(A.draco)showed the highest rate of scatter-hoarding and the highest recovery advantage compared with the other 2 larger species(N.confucianus and L.edwardsi).Our results suggest that scatter-hoarding benefits cache owners in food competition,supporting the pilferage avoidance hypothesis.Therefore,scatter-hoarding behavior should be favored by natural selection,and plays a significant role in species coexistence of rodent community and in the formation of mutualism between seeds and rodents in forest ecosystems.展开更多
基金Supported by the Fundamental Research Funds for the Central Universities(HEUCFM181203)
文摘The multi-orifice plate gas sparger, mainly composed of a multi-orifice plate and a gas chamber, is one of the most common sparger facilities.The aeration performance of multi-orifice plate has a close relation with the multiorifice plate configuration.In addition, the weeping phenomenon has a considerable influence on the gas chamber condition which affects the bubble detachment volume directly.This paper conducts a set of visual experiments to study the influence of multi-orifice configuration and gas chamber condition on the aeration performance of gas sparger.For multi-orifice plate, an improved theoretical model is proposed which considers the wave effect of the previous bubbles generated from adjacent orifices and the variance of the number of active bubbling orifice.A parameter is proposed to evaluate the aeration performance in order to overcome the difficulty caused by the randomness of bubble formation process.The experimental results suggest that the gas chamber filled with water is in favor of large bubble formation.The influence of the pitch of orifice on aeration performance can only be observed in high-restricted case.According to the theoretical model and experimental results, the influences of gas flow rate and the number of open orifices on the aeration performance are analyzed and a design criterion for the number of open orifice is proposed.
基金the National Key Research and Development Program of China(No.2019YFE0124700)the Scientific Research Foundation of Third Institute of Oceanography,MNR(No.2020017)。
文摘Pico-and nano-eukaryotic plankton are important members of marine ecosystems.To understand their community structure and spatio-temporal variations in the Beibu Gulf,and to study the impact of Changjiang Nuclear Power Plant(CNPP)located in the northwest coast of the Hainan Island on the eukaryotic plankton,we studied these issues in the coastal water near CNPP bimonthly from February 2018 to January 2019 via 18 S Illumina sequencing.The results reveal a higher genetic alphadiversity and less beta-diversity of the plankton community in small-size(0.45-5μm and 5-20μm)fractions than in large-size(20-200μm and>20μm)fractions.The small-sized phytoplankton,including Micromonas(Chlorophyta)and Minutocellus(Bacillariophyta),as well as heterotrophic plankton,including Paraphysomonas(Chrysophyceae),Ellobiopsis(Dinoflagellates),and Syndiniales(Dinoflagellates),took up a considerable proportion in eukaryotic plankton community.In addition,it showed a slight temperature increase and no significant difference in eukaryotic plankton community between the outfall of CNPP and other sampling sites,suggesting that the impact of the thermal discharge from the CNPP on local eukaryotic plankton community was limited.
基金Supported by the Fundamental Research Funds for the Central Universities(HEUCFP201855)
文摘Bubble coalescence reduces specific area and weakens the work performance of bubble column. The bubble coalescence near gas sparger which is caused mainly by bubble growing is different from the ones occurring in major liquid. Bubble coalescence efficiency near gas sparger is influenced by many factors including sparger configuration, gas flow rate, bubble deformation, solution composition, etc. This work has conducted a set of visual experiments to study the coalescence characteristics near multi-orifice plate. The experiment parameters cover a wide range of conditions including large scope of gas flow rate,different kinds of solution and orifice configurations. The experimental results suggest that coalescence time is applicable to reflect the influence of the pitch of orifices and gas flow rate on bubble coalescence efficiency. As the number of orifices increases, bubble coalescence efficiency is reduced by the disturbance from the bubbles at adjacent orifices. A hindering coefficient is used to consider the hindering effect of additives on bubble coalescence efficiency. Finally a new calculation expression is established to predict bubble coalescence efficiency near multi-orifice plate whose fundamental form is based on the logistic curve of binary response. The calculated values that refer to this calculation expression are well consistent with the experimental results.
基金Supported by the Scientifi c Research Foundation of Third Institute of Oceanography,MNR(No.2017023)the National Natural Science Foundation of China(Nos.41806154,41876173,42076144)+1 种基金the Special Foundation for National Science and Technology Basic Research Program of China(Nos.2018FY100200,2018FY100100)the Project of Southern Marine Science and Engineering Guangdong Laboratory(No.311021004)。
文摘Amphidinium species are amongst the most abundant benthic dinoflagellates in marine intertidal sandy ecosystems.Some of them are able to produce a variety of bioactive compounds that can have both harmful effects and pharmaceutical potentials.The diversity of Amphidinium in shallow waters along the Chinese coast was investigated by isolating single cells from sand,coral,and macroalgal samples collected from 2012 to 2020.Their morphologies were subjected to examination using light microscopy(LM)and scanning electron microscopy(SEM).A total of 74 Amphidinium strains were morphologically identified,belonging to 11 species:A.carterae,A.gibbosum,A.operculatum,A.massartii,A.cf.massartii,A.fijiensis,A.pseudomassartii,A.steinii,A.thermaeum,A.theodori,A.tomasii,as well as an undefined species.The last seven species have not been previously reported in Chinese waters.Amphidinium carterae subcladesⅠ,Ⅱ,andⅣwere found in the South China Sea,while subcladeⅢwas only found in the Yellow Sea.Threadlike body scales were observed on the surface of subcladesⅢ and Ⅳ,supporting the idea that A.carterae might contain several different species.Large subunit ribosomal RNA(LSU rRNA)sequencesbased phylogeny revealed two groups(GroupsⅠandⅡ)within Amphidinium,which is consistent with the relative position of sulcus(in touch with cingulum or not).In addition,large differences in morphology and molecular phylogeny between A.operculatum(the type species of Amphidinium)and other species,suggest that a subdivision of Amphidinium might be needed.The pigment profiles of all available strains were analyzed by high performance liquid chromatography(HPLC).Eleven pigments,including peridinin,diadinoxanthin,diatoxanthin,pheophorbide(and pheophorbide a),antheraxanthin,β-carotene,and four different chlorophylls were detected.The high pheophorbide/pheophorbide a ratio in Amphidinium implies that it may be a good candidate as a natural source of photosensitizers,a well-known anticancer drug.
基金Fundamental Research Funds for the Central Universities(HEUCFP201855)。
文摘Weeping is an adverse phenomenon which results in higher pressure drop and poorer aeration performance.Visual experiments have been conducted to study the mechanism by which weeping impairs the work performance of multi-orifice plate.A theoretical model is improved to analyze the weeping phenomenon of multiorifice plate based on potential flow theory.The relations of different bubbling conditions and weeping rate are analyzed.Weeping condition and average weeping rate have relation with the driven pressure differential and dynamic variation of gas chamber pressure.In addition,a set of experiments are designed to study the influence of various factors on weeping rate.The bubble coalescence during bubble formation is a fatal factor determining weeping rate,so the relation between weeping rate and gas flow rate is concerned with the pitch of orifices and orifice diameter.There is a critical plate thickness which is in favor of weeping.
基金The Zhejiang Public Welfare Technology Research and Social Development Project of 2013 of China under contract Nos 2013C33081 and 2013C32040the National Natural Science Foundation of China under contract No.41306095the Doctoral Fund of Ministry of Education of China under contract No.J20130101
文摘The dinoflagellate cyst assemblages on the Nanji Island in the East China Sea, are documented at the first time to construct a quantitative overview of the cyst bank from 2014 to 2015. Thirty-four morphotypes from six groups are identified and quantified at eight sampling sites around the island, including a high proportion of potentially toxigenic species(14%). Autotrophic dinocysts constitute 74% of the total cyst counts, which is relatively low(two to thirty-three per millilitre sediment) compared with previous studies in adjacent areas. Scrippsiella trochoidea and Protoperidinium avellana are the most abundant autotrophic and heterotrophic species, respectively. A multivariate analysis is performed to assess associations between dinocysts and abiotic or biotic variables.Differentiation among seasons is evident in the detrended correspondence analysis(DCA) ordination plot, while a spatial pattern is not clearly revealed despite heterogeneity of the hydrodynamic conditions between sampling sites. Soluble reactive phosphate, the ratio of nitrogen to phosphorus concentrations and Karenia mikimotoi bloom are the three factors significantly(P<0.05) related to surface sediment cyst assemblage defined by the canonical correspondence analysis(CCA), highlighting the importance of nutrient regime to a dinocyst distribution in this area. Although attempts to address the origin of HAB events in recent years using seed banks have failed, knowledge can be valuable for further investigation of dinocyst dynamics and potential toxin threats on the Nanji Island.
基金This research was supported by the National Natural Science Foundation of China （Nos. 81573267, 91413103 and 91213303）.
文摘The lupane-type triterpenoids are endowed with a wide range of biological activities such as antiviral, anti-inflammatory and anticancer activity. We describe here its potential application in Alzheimer＇s disease （AD） treatment as an inhibitor of PS1/BACE1 interaction. 3-a-Akebonoic acid, which emanated from a high throughput screening （HTS）, was discovered to interfere with P S 1/BACE 1 interaction and reduce amyloid β-protein （Aβ） production. In view of the limited source, we instead used naturally rich betulinic acid （compound 2） as starting material for lead optimization and a focused library of its derivatives was constructed to gain a better understanding of the structure activity relationship （SAR） of triterpenoid-type inhibitor of PS1/BACE1 interaction. Compound 22 was finally chosen as the most potent PS 1/BACE 1 interaction inhibitor, which reduced Aβgeneration effectively.
文摘The revolutionary induced pturipotent stem celt （iPSC） technoLogy provides a new means for celt replacement therapies and drug screening. Small molecule compounds have been found extremely useful to improve the generation of iPSCs and understand the repro- gramming mechanism. Here we report the identification of a novel chemical, CYT296, which improves OSKM-mediated induction of iPSCs for 〉10 folds and enables efficient reprogramming with only Oct4 in combination with other small molecules. The derived iPSCs are genuinely pluripotent and support the development oftwo ＇All-iPSC＇ mice by tetraploid complementation. CYT296 profoundly impacts heterochromatin formation without affecting celt viability. MEFs treated with CYT296 exhibit de-condensed chromatin structure with markedly reduced loci containing heterochromatin protein 1α （HPIoL） and H3K9me3, which is very similar to the chromatin configuration in embryonic stem cells （ESCs）. Given that an open chromatin structure serves as a hallmark of pLuripotency and has to be acquired to fulfill reprogramming, we propose that CYT296 might facilitate this process by disrupting condensed chromatin, thereby creating a more favorable environment for reprogramming. In agreement of this idea, shRNA targeting HP1α also promotes the generation of iPSCs. Thus current findings not only provide a novel chemical for efficient iPSC induction, but also suggest a new approach to regulate somatic cell reprogramming by targeting chromatin de-condensation with small molecules.
基金supported by the key project of the Chinese Academy of Sciences(XDB11050300,KSZD-EW-TZ-008)the key project of the National Natural Science Foundation of China(31330013).
文摘The scatter-hoarding behavior of granivorous rodents plays an important role in seed dispersal and seedling regeneration of trees,as well as the evolution of several well-known mutualisms between trees and rodents in forest ecosystems.Because it is difficult to identify seed hoarders and pilferers under field conditions by traditional methods,the full costs incurred and benefits accrued by scatter-hoarding have not been fully evaluated in most systems.By using infrared radiation camera tracking and seed tagging,we investigated the benefits and losses of scatter-hoarded seeds(Camellia oleifera)for 3 sympatric rodent species(Apodemus draco,Niviventer confucianus and Leopoldamys edwardsi)in a subtropical forest of Southwest China during 2013 to 2015.We established the relationships between the rodents and the seeds at the individual level.For each rodent species,we calculated the cache recovery rate of cache owners,as well as conspecific and interspecific pilferage rates.We found that all 3 sympatric rodent species had a cache recovery advantage with rates that far exceeded average pilferage rates over a 30-day tracking period.The smallest species(A.draco)showed the highest rate of scatter-hoarding and the highest recovery advantage compared with the other 2 larger species(N.confucianus and L.edwardsi).Our results suggest that scatter-hoarding benefits cache owners in food competition,supporting the pilferage avoidance hypothesis.Therefore,scatter-hoarding behavior should be favored by natural selection,and plays a significant role in species coexistence of rodent community and in the formation of mutualism between seeds and rodents in forest ecosystems.
