Plate culture counting and strain isolation methods were utilized to assess the species richness and abundance of planktonic and attached bacteria on glass plates in the surface and bottom seawater of Qingdao Middle H...Plate culture counting and strain isolation methods were utilized to assess the species richness and abundance of planktonic and attached bacteria on glass plates in the surface and bottom seawater of Qingdao Middle Harbor over a year,with monthly and quarterly sampling.Both species richness and bacterial numbers exhibited seasonal variations.Specifically,the abundance of attached bacteria and bacterioplankton peaked in June and July,corresponding to higher water temperatures in summer and autumn,while lower abundances were noted in January and December during cooler periods.Throughout the year,the species richness of attached bacteria consistently exceeded that of planktonic bacteria in both shallow and deep waters.Pseudoalteromonas emerged as the most prevalent genus among both planktonic and attached bacteria in surface and bottom seawater samples.Furthermore,the magnitude of changes in species richness and abundance for attached bacteria(0.66×10^(5)-15.85×10^(5)CFU/cm^(2))was greater than that observed for planktonic bacteria(0.58×10^(8)-5.33×10^(8)CFU/L).We propose that the attached bacterial populations,situated in limited microenvironments within the larger seawater ecosystem,exhibit heightened sensitivity to environmental fluctuations,resulting in more rapid shifts in population dynamics and lower ecological stability.The theoretical implications and potential applications of these findings warrant further investigation.展开更多
Background:Bullying is a current social and educational problem with detrimental consequences in adolescence and later life stages.Previous research has explored the risk or protective factor at different socio-ecolog...Background:Bullying is a current social and educational problem with detrimental consequences in adolescence and later life stages.Previous research has explored the risk or protective factor at different socio-ecological levels,but further integration is needed to examine the relationships of family characteristics.This study examines how parenting style and attachment relate to adolescents’bullying and cyberbullying,and whether parental phubbing mediates these links.Methods:Grounded in social bonding theory,we surveyed a cross-sectional convenience sample of U.S.college students(N=545;Mean_(age)=19.60,SD=1.41)who retrospectively reported middle/high-school experiences from Massachusetts,Colorado,and Virginia.Measures followed established traditions of bullying involvement,parenting style,and partner phubbing).Linear regressions tested associations among parenting style,attachment to parents/teachers,parental phubbing,and bullying/cyberbullying offending and victimization.Results:Stronger parental attachment and democratic(authoritative)parenting were associated with lower bullying victimization,and teacher attachment was protective for offline and overall offending.Critically,parents’excessive personal technology use(phubbing)mediated the link between democratic parenting and bullying outcomes:high parental device use attenuated or nullified the protective association of democratic parenting.Conclusion:Findings reaffirm the value of nurturing,boundary-setting parenting and close parent–child/teacher bonds,while highlighting a contemporary risk—parental device-related inattention.Despite rapid technological change,the core need for stable human connection remains central to reducing bullying involvement.展开更多
This study analyzes the community structure, the quantity changes of the algae and the effect of important environmental factors and estimates the total biomass of the attached green algae in the survey areas. The stu...This study analyzes the community structure, the quantity changes of the algae and the effect of important environmental factors and estimates the total biomass of the attached green algae in the survey areas. The study uses data from surveys of the attached green algae on the Porphyra yezoensis aquaculture rafts and data regarding the environmental factors from October 2010 to April 2011 in the Subei Shoal. The attached green algae on the rafts included Ulva prolifera, Capsosiphon groenlandicus, U. linza, U. intestinalis, U. clathrata, and U. cornpressa. The biomass changes of the attached green algae exhibited an inverted parabola： the biomass was the highest （14 898 t） in April, and was the second highest （2 034 t） in November; it was lowest in February （only 729 t） and increased sharply from March to April. The species diversity differed significantly among the seasons. In September and October, when the P. yezoensis aquaculture rafts were initially set up, the attached green algae had a high biodiversity, while from December to the next February, a variety of green algae species coexisted on the rafts, although the biomass was low, and from March to April, as the biomass increased sharply, the species diversity dropped to the minimum. During this time, C. groenlandicus was apparently dominant with the maximum biomass proportion up to 80%, while the U. prolifera proportion increased exponentially to 20% to 40%. The water temperature had a direct regulating effect on the biomass and the species succession of the attached green algae. The estimation of the community dynamics and the biomass of the green algae provided the evidence needed to track the origin of the large-scale green tide in the southern Yellow Sea.展开更多
The quantitative change and size distribution of particles in the effluents from a sand filter and a granular activated carbon （GAC） filter in a drinking water treatment plant were investigated. The average total co...The quantitative change and size distribution of particles in the effluents from a sand filter and a granular activated carbon （GAC） filter in a drinking water treatment plant were investigated. The average total concentration of particles in the sand filter effluent during a filter cycle was 148 particles/mL, 27 of which were larger than 2 μm in size. The concentration in the GAC effluent （561 particles/mL） was significantly greater than that in the sand filter effluent. The concentration of particles larger than 2 μm in the GAC filter effluent reached 201 particles/mL, with the amount of particles with sizes between 2 μm and 15 μm increasing. The most probable number （MPN） of carbon fines reached 43 unit/L after six hours and fines between 0.45 μm and 8.0 μm accounted for more than 50%. The total concentration of outflowing bacteria in the GAC filter effluent, 350 CFU （colony-forming units） /mL, was greater than that in the sand filter effluent, 210 CFU/mL. The desorbed bacteria concentration reached an average of 310 CFU/mg fines. The disinfection efficiency of desorbed bacteria was lower than 40% with 1.5 mg/L of chlorine. The disinfection effect showed that the inactivation rate with 2.0 mg/L of chloramine （90%） was higher than that with chlorine （70%）. Experimental results indicated that the high particle concentration in raw water and sedimentation effluent led to high levels of outflowing particles in the sand filter effluent. The activated carbon fines in the effluent accounted for a small proportion of the total particle amount, but the existing bacteria attached to carbon fines may influence the drinking water safety. The disinfection efficiency of desorbed bacteria was lower than that of free bacteria with chlorine, and the disinfection effect on bacteria attached to carbon fines with chloramine was better than that with only chlorine.展开更多
Green tides caused by the unusual accumulation of high floating Ulva prolifera have occurred regularly in the Yellow Sea since 2007.The primary source of the Yellow Sea green tides is the attached algae on the Pyropia...Green tides caused by the unusual accumulation of high floating Ulva prolifera have occurred regularly in the Yellow Sea since 2007.The primary source of the Yellow Sea green tides is the attached algae on the Pyropia aquaculture rafts in the Subei Shoal.Ulva prolifera and Blidingia(Italic)sp.are the main species observed on Pyropia aquaculture rafts in the Subei Shoal.We found that U.prolifera has strong buoyancy and a rapid growth rate,which may explain why it is the dominant species of green tides that occur in the China's sea area of the Yellow Sea.The growth rate of floating U.prolifera was about 20%–31%d–1,which was much higher than Blidingia(Italic)sp.There were about 1.7×104 t of attached algae on the Pyropia aquaculture rafts in May 2012.We found that 39%of attached algae could float when the tide rose in the Subei Shoal,and U.prolifera accounted for 63%of the floating algae.Our analysis estimated that about 4000 t of attached U.prolifera floated into the surrounding waters of the Subei Shoal during the recycling period of aquaculture rafts.These results suggest that the initial floating biomass of large-scale green tides in the Yellow Sea is determined by the U.prolifera biomass attached to Pyropia aquaculture rafts,further impacting the scale of the green tide。展开更多
Network attached storage (NAS) with the properties of improved scalability, simplified management, low cost and balanced price performance, is desirable for high performance storage systems applied to extensive area...Network attached storage (NAS) with the properties of improved scalability, simplified management, low cost and balanced price performance, is desirable for high performance storage systems applied to extensive areas. Unfortunately, it also has some disadvantages such as increased network workload, and inconvenience in disaster recovery. To overcome these disadvantages, we propose a channel bonding technique and provide hot backup functions in the designed NAS system, named HUSTserver. Channel bonding means merging multiple Ethernet channels into integrated one, and that the data packets can be transferred through any available network channels in a parallel mode. The hot backup function provides automatic data mirroring among servers. In this paper, we first describe the whole system prototype from a software and hardware architecture view. Then, multiple Ethernet and hot backup technologies that distinguish HUSTserver from others are discussed in detail. The findings presented demonstrate that network bandwidth can be scaled by the use of multiple commodity networks. Dual parallel channels of commodity 100 Mbps Ethernet are both necessary and sufficient to support the data rates of multiple concurrent file transfers. And the hot backup function introduced in our system provides high data accessibility.展开更多
Attached cultivation is a promising method for microalgal biomass production. Filamentous oleaginous microalga Tribonema minus(hereafter T. minus) has shown a remarkable potential for biofuel production in terms of it...Attached cultivation is a promising method for microalgal biomass production. Filamentous oleaginous microalga Tribonema minus(hereafter T. minus) has shown a remarkable potential for biofuel production in terms of its high lipid content. However, the strain has only been cultivated in suspended cultivation systems including open pond and closed photobioreactors. Here, we attempted to study the attached cultivation of T. minus, which might be helpful for its scale-up cultivation and industrial applications. As the results, the optimal conditions for T. minus growth in the attached biofilm are 200 μmol photons m^-2 s^-1 of light intensity and 5% of CO2, and the maximum biomass density of 223 g m^-2 has been achieved under the light intensity. The non-woven fabric as substratum was found as the best substratum in thin layer attached bioreactor, on which the average biomass productivity of T. minus is about(9.73 ± 2.19) g m^-2)d^-1. Furthermore, two attached bioreactor systems, rotary drum and rotation disc, were designed following the light dilution strategy and introduced into T. minus cultivation. The highest footprint areal biomass productivity of these two systems is 33 and 47.1 g m^-2 d^-1, respectively, much higher than that in suspended cultivation system. The results shows that T. minus can be cultured with attached cultivation method to improve its biomass productivity.展开更多
Cyclin B1 is a key regulatory protein controlling cell cycle progression in vertebrates. Cyclin B1 binds CDK1, a cy-clin-dependent kinase catalytic subunit, forming a complex that orchestrates mitosis through phosphor...Cyclin B1 is a key regulatory protein controlling cell cycle progression in vertebrates. Cyclin B1 binds CDK1, a cy-clin-dependent kinase catalytic subunit, forming a complex that orchestrates mitosis through phosphorylation of key proteins. Cyclin B1 regulates both the activation of CDK1 and its subcellular localization, which may be critical for substrate selection. Here, we demonstrate that cyclin B1 is concentrated on the outer plate of the kinetochore during prometaphase. This localization requires the cyclin box region of the protein. Cyclin B1 is displaced from individual kinetochores to the spindle poles by microtubule attachment to the kinetochores, and this displacement is dependent on the dynein/dynactin complex. Depletion of cyclin B1 by vector-based siRNA causes inefficient attachment between kinetochores and microtubules, and chromosome alignment defects, and delays the onset of anaphase. We conclude that cyclin B1 accumulates at kinetochores during prometaphase, where it contributes to the correct attachment of mi- crotubules to kinetochores and efficient alignment of the chromosomes, most likely through localized phosphorylation of specific substrates by cyclin B1-CDK1. Cyclin B1 is then transported from each kinetochore as microtubule attachment is completed, and this relocalization may redirect the activity of cyclin B1-CDK1 and contribute to inactivation of the spindle assembly checkpoint.展开更多
The stigma associated with the disease may be as subtle as avoidance,or dramatic as physical aggression.COVID-19 has begun to cause social disruption by growing disease-related stigma and xenophobia against some cultu...The stigma associated with the disease may be as subtle as avoidance,or dramatic as physical aggression.COVID-19 has begun to cause social disruption by growing disease-related stigma and xenophobia against some cultural,national,racial or religious groups worldwide.1 People of East Asian origin and those with facial features like them,or those with a travel history to areas affected by the outbreak,are especially being subjected to xenophobia in personal contact and online threats.COVID-19 has arisen as an unknown and newly emerged highly contagious infection that has spread rapidly across the globe and is associated with high mortality,leading to fear of encountering those infected.2 Leaders across the world have taken strict measures such as lockdowns and shutdown of various vital services that have caused chaos in people’s lives and increased concerns about the disease.3 Box 1 lists the factors leading to stigmatisation towards those infected with COVID-19.展开更多
Bacterial community dynamics and copper leaching with applied forced aeration were investigated during low-grade copper sulphide bioleaching to obtain better bioleaching efficiency.Results illustrated that appropriate...Bacterial community dynamics and copper leaching with applied forced aeration were investigated during low-grade copper sulphide bioleaching to obtain better bioleaching efficiency.Results illustrated that appropriate aeration improved bacterial concentrations and leaching efficiencies.The highest bacterial concentration and Cu^(2+)concentration after 14-d leaching were 7.61×10^(7) cells·mL^(−1) and 704.9 mg·L^(−1),respectively,at aeration duration of 4 h·d^(−1).The attached bacteria played a significant role during bioleaching from 1 to 7 d.However,free bacteria dominated the bioleaching processes from 8 to 14 d.This phenomenon was mainly caused by the formation of passivation layer through Fe3+hydrolysis along with bioleaching,which inhibited the contact between the attached bacteria and ore.Meanwhile,16S rDNA analysis verified the effect of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans on the bioleaching process.The results demonstrate the importance of free and attached bacteria in bioleaching.展开更多
In order to investigate the effects of processing pH stimulation on bioleaching of chalcopyrite by moderate thermophiles,copper leaching rates and the dynamics of microbial community structures of free and attached ce...In order to investigate the effects of processing pH stimulation on bioleaching of chalcopyrite by moderate thermophiles,copper leaching rates and the dynamics of microbial community structures of free and attached cells were monitored. The results indicated that when the processing pH values were respectively adjusted to 1.0 and 3.0 on day 14, both free and attached cells experienced an adaptive phase. Meanwhile, the copper leaching rates were 86.9% and 64.0%,respectively, as opposed to a copper leaching rate of 87.5% in the control group without pH stimulation. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis suggested that pH stimulation imposed less impact on the attached organisms than on the free cells, indicating that the attached cells were more resistant to processing pH stimulation than the free cells. Furthermore, adjusting processing pH to 3.0 significantly disrupted both free and attached microbial communities, and the bioleaching system could not recover to the normal status as the control group.展开更多
When non-cooperative body attachment occurs in space, the inertia of the new combination and the change of the system's momentum are unknown.This uncertainty may lead to the instability of the spacecraft's att...When non-cooperative body attachment occurs in space, the inertia of the new combination and the change of the system's momentum are unknown.This uncertainty may lead to the instability of the spacecraft's attitude control.In order to solve this problem, we propose an adaptive control scheme based on the inertia estimation of the new, combined system of non-cooperative body and satellite.This method can allow the new combination of different situations to reach a stable state with a high level of precision and speed.In this paper, the stability of the adaptive control scheme is proven by constructing a Lyapunov function.A simulation environment in which a non-cooperative body attaches to a satellite attaches to is constructed.The simulation shows that the attitude error converges to a small field when using the control scheme, regardless of unfavorable cases, including unknown inertia parameters, added momentum.In addition, the simulation results show the strong robustness of the control scheme for the new combination.展开更多
A feasible method to improve the reliability and processing efficiency of large vibrating screen via the application of an elastic screen surface with multiple attached substructures （ESSMAS） was proposed. In the ES...A feasible method to improve the reliability and processing efficiency of large vibrating screen via the application of an elastic screen surface with multiple attached substructures （ESSMAS） was proposed. In the ESSMAS, every screen rod, with ends embedded into elastomer, is coupled to the main screen structure in a relatively flexible manner. The theoretical analysis was conducted, which consists of establishing dynamic model promoted from the fuzzy structure theory as well as calculating for the equivalent stiffness of each attached structure. According to the numerical simulation using the NEWMARK-fl integration method, this assembling pattern significantly leads to the screen surface/rod having larger vibration intensity than that of the corresponding position on screen structure, which specifically, with an averaged acceleration amplitude increasing ratio of 11.37% in theoretical analysis and 20.27% in experimental test. The experimental results, within a tolerant error, also confirm the established model and demonstrate the feasibility of ESSMAS.展开更多
Novel solid-contact perchlorate sensors based on cobalt phthalocyanine-C-monocarboxylic acid (I), and cobalt phthalocyanine-C,C,C,C-tetracarboxylic acid (II) as free ionophores and covalently attached to polyacryla- m...Novel solid-contact perchlorate sensors based on cobalt phthalocyanine-C-monocarboxylic acid (I), and cobalt phthalocyanine-C,C,C,C-tetracarboxylic acid (II) as free ionophores and covalently attached to polyacryla- mide (PAA)—ionophores III and IV, respectively were prepared. The all solid-state sensors were constructed by the application of a thin film of a polymer cocktail containing a phthalocyanine ionophore and cetyltrimethylammonium bromide (CTMAB) as a lipophilic cationic additive onto a gold electrode precoated with the conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT) as an ion and electron transducer. The sensor with 10.3% of ionophore (III) covalently attached to plasticizer-free poly (butyl methacrylate-co-do- decyl methacrylate) (PBDA) exhibited a good selectivity for perchlorate and discriminated many ions, in- cluding F–, Cl–, Br–, I–, SCN–, , S2– and . The covalent attachment of the ionophore to the polymer resulted in a near-Nernstian anionic slope of –62.3 mV/decade whereas a super-Nernstian slope of –79.9 mV/ decade was obtained for the free ionophore. The sensor covered a linear concentration range of 5 × 10–9 - 1 × 10–2 mol?L–1 with a lower detection limit (LDL) of 1 × 10–9 mol?L–1 and gave a stable response over a pH range of 4 - 10.5. The all-solid state sensors were utilized for the selective flow injection potentiometric determination of perchlorate in natural water and human urine samples in the nanomolar concentration range.展开更多
Numerical simulations of the non-spherical evolution of a pulsating bubble interacting with a stationary air bubble attached to a fixed structure were performed using a three-dimensional boundary integral method by im...Numerical simulations of the non-spherical evolution of a pulsating bubble interacting with a stationary air bubble attached to a fixed structure were performed using a three-dimensional boundary integral method by implementing the mirror image method to simplify the processing of the numerical model. Code validation was accomplished by comparing the numerical results with the laboratory experimental data obtained in our previous study. Complex phenomena were observed, including three types of bubble jet forms, which depended strongly on the distance parameter with respect to the initial location of the bubble from the plate, the bubble strength parameter and the initial air bubble radius parameters. The results of the simulations provide detail insight into interesting bubble jetting phenomena,such as bubble splitting, jets moving away from the plate, and bubble shedding. The dimensionless distance parameter and the initial air bubble radius parameter play a major role in determining the shapes of two bubbles and the jetting direction. The air bubble strength parameter did not change the bubble jet direction but influenced the bubble shape.The detachment of the attached air bubble under oscillating bubble suction was easily observed for a small initial air bubble. These results showed that bubble jetting toward the plate was manipulated through the effect of attached air bubble, and that cavitation-based applications and underwater explosion bubble may benefit from this erosion mitigation approach.展开更多
Inhalation of 222Rn progeny in the domestic environment contributes the greatest fraction of the natural radiation exposure to the public. The ultrafine activity of these progeny amounts up to about l 0 percent of the...Inhalation of 222Rn progeny in the domestic environment contributes the greatest fraction of the natural radiation exposure to the public. The ultrafine activity of these progeny amounts up to about l 0 percent of the total activity （attached and ultrafine）, but is considered to yield about 50 percent of the total radiation dose. Therefore, measurements of ultrafine fraction are essential for the estimation of radiation dose. The current study presents measured data on the total equilibrium equivalent concentration （EEC） and ultrafine equilibrium equivalent concentration （EECUn）, ultrafine fraction （fb）, attached and unattached activity size distributions of radon progeny in the low ventilated rooms at Minia University, Minia city, Egypt. A screen diffusion battery was used for collection the ultrafine fraction and measuring the total activity concentration of radon progeny. The attached activity size distribution of 214pb is determined by using a low pressure cascade impactor. The EEC of radon progeny varied between 1.3 and 18.9 Bq/m3 with a mean value of 5.2 ± 0.48 Bq/m2. The mean activity thermodynamic diameter （AMTD） ofultrafine of radon progeny was determined to be 1.26 nm with relative mean geometric standard deviations （GSD） of 1.3. The ultrafine fraction of radon progeny, fb, has a range 0.01 to 0.21 with an average of 0.08 ± 0.03. A relative mean GSD of 2.7 was determined for attached 2Lapb at a mean active median aerodynamic diameter （AMD） of 350 nm. Based on the above experimental results, the deposition fractions have been evaluated in each air way generation through the human lung by applying a lung deposition model. The bronchial deposition efficiencies of particles in the size range of attached radon progeny were found to be lower than those of ultrafine progeny. The effect of radon progeny deposition by adult male has been also studied for various levels of physical exertion. The dose conversion factor has been discussed as a function of fb.展开更多
An algorithm is presented to analyze the free vibration in a system composed of a cable with discrete elements, e.g., a concentrated mass, a translational spring, and a harmonic oscillator. The vibrations in the cable...An algorithm is presented to analyze the free vibration in a system composed of a cable with discrete elements, e.g., a concentrated mass, a translational spring, and a harmonic oscillator. The vibrations in the cable are modeled and analyzed with the Lagrange multiplier formalism. Some fragments of the investigated structure are modeled with continuously distributed parameters, while the other fragments of the structure are modeled with discrete elements. In this case, the linear model of a cable with a small sag serves as a continuous model, while the elements, e.g., a translational spring, a concentrated mass, and a harmonic oscillator, serve as the discrete elements. The method is based on the analytical solutions in relation to the constituent elements, which, when once derived, can be used to formulate the equations describing various complex systems compatible with an actual structure. The numerical analysis shows that, the method proposed in this paper can be successfully used to select the optimal parameters of a system composed of a cable with discrete elements, e.g., to detune the frequency resonance of some structures.展开更多
基金The National Natural Science Foundation of China under contract Nos 42206126 and 42076044the Natural Science Foundation of Shandong Province under contract No.ZR2021QD099.
文摘Plate culture counting and strain isolation methods were utilized to assess the species richness and abundance of planktonic and attached bacteria on glass plates in the surface and bottom seawater of Qingdao Middle Harbor over a year,with monthly and quarterly sampling.Both species richness and bacterial numbers exhibited seasonal variations.Specifically,the abundance of attached bacteria and bacterioplankton peaked in June and July,corresponding to higher water temperatures in summer and autumn,while lower abundances were noted in January and December during cooler periods.Throughout the year,the species richness of attached bacteria consistently exceeded that of planktonic bacteria in both shallow and deep waters.Pseudoalteromonas emerged as the most prevalent genus among both planktonic and attached bacteria in surface and bottom seawater samples.Furthermore,the magnitude of changes in species richness and abundance for attached bacteria(0.66×10^(5)-15.85×10^(5)CFU/cm^(2))was greater than that observed for planktonic bacteria(0.58×10^(8)-5.33×10^(8)CFU/L).We propose that the attached bacterial populations,situated in limited microenvironments within the larger seawater ecosystem,exhibit heightened sensitivity to environmental fluctuations,resulting in more rapid shifts in population dynamics and lower ecological stability.The theoretical implications and potential applications of these findings warrant further investigation.
文摘Background:Bullying is a current social and educational problem with detrimental consequences in adolescence and later life stages.Previous research has explored the risk or protective factor at different socio-ecological levels,but further integration is needed to examine the relationships of family characteristics.This study examines how parenting style and attachment relate to adolescents’bullying and cyberbullying,and whether parental phubbing mediates these links.Methods:Grounded in social bonding theory,we surveyed a cross-sectional convenience sample of U.S.college students(N=545;Mean_(age)=19.60,SD=1.41)who retrospectively reported middle/high-school experiences from Massachusetts,Colorado,and Virginia.Measures followed established traditions of bullying involvement,parenting style,and partner phubbing).Linear regressions tested associations among parenting style,attachment to parents/teachers,parental phubbing,and bullying/cyberbullying offending and victimization.Results:Stronger parental attachment and democratic(authoritative)parenting were associated with lower bullying victimization,and teacher attachment was protective for offline and overall offending.Critically,parents’excessive personal technology use(phubbing)mediated the link between democratic parenting and bullying outcomes:high parental device use attenuated or nullified the protective association of democratic parenting.Conclusion:Findings reaffirm the value of nurturing,boundary-setting parenting and close parent–child/teacher bonds,while highlighting a contemporary risk—parental device-related inattention.Despite rapid technological change,the core need for stable human connection remains central to reducing bullying involvement.
基金The National Basic Research Program (973 Program) of China under contract No.2010CB428703the National Natural Science Foundation of China under contract No.41306171+3 种基金the National Research Foundation-Shandong Province United Fund under contract No.U1406403the Qingdao Public Domain to Support Science and Technology Project under contract No.13–4–1–68–hythe Marine and Basic Research Funds of the First Institute of Oceanography,SOA under contract No.2015G09MOST International S&T Cooperation Program under contract No.2010DFA24340
文摘This study analyzes the community structure, the quantity changes of the algae and the effect of important environmental factors and estimates the total biomass of the attached green algae in the survey areas. The study uses data from surveys of the attached green algae on the Porphyra yezoensis aquaculture rafts and data regarding the environmental factors from October 2010 to April 2011 in the Subei Shoal. The attached green algae on the rafts included Ulva prolifera, Capsosiphon groenlandicus, U. linza, U. intestinalis, U. clathrata, and U. cornpressa. The biomass changes of the attached green algae exhibited an inverted parabola： the biomass was the highest （14 898 t） in April, and was the second highest （2 034 t） in November; it was lowest in February （only 729 t） and increased sharply from March to April. The species diversity differed significantly among the seasons. In September and October, when the P. yezoensis aquaculture rafts were initially set up, the attached green algae had a high biodiversity, while from December to the next February, a variety of green algae species coexisted on the rafts, although the biomass was low, and from March to April, as the biomass increased sharply, the species diversity dropped to the minimum. During this time, C. groenlandicus was apparently dominant with the maximum biomass proportion up to 80%, while the U. prolifera proportion increased exponentially to 20% to 40%. The water temperature had a direct regulating effect on the biomass and the species succession of the attached green algae. The estimation of the community dynamics and the biomass of the green algae provided the evidence needed to track the origin of the large-scale green tide in the southern Yellow Sea.
基金supported by the National Natural Science Foundation of China (Grant No 50638020)the National Key High-Tech Program (863) of China (Grant No 2006AA06Z311)the Natural Science Foundation of Jiangsu Province (Grant No BK2006170)
文摘The quantitative change and size distribution of particles in the effluents from a sand filter and a granular activated carbon （GAC） filter in a drinking water treatment plant were investigated. The average total concentration of particles in the sand filter effluent during a filter cycle was 148 particles/mL, 27 of which were larger than 2 μm in size. The concentration in the GAC effluent （561 particles/mL） was significantly greater than that in the sand filter effluent. The concentration of particles larger than 2 μm in the GAC filter effluent reached 201 particles/mL, with the amount of particles with sizes between 2 μm and 15 μm increasing. The most probable number （MPN） of carbon fines reached 43 unit/L after six hours and fines between 0.45 μm and 8.0 μm accounted for more than 50%. The total concentration of outflowing bacteria in the GAC filter effluent, 350 CFU （colony-forming units） /mL, was greater than that in the sand filter effluent, 210 CFU/mL. The desorbed bacteria concentration reached an average of 310 CFU/mg fines. The disinfection efficiency of desorbed bacteria was lower than 40% with 1.5 mg/L of chlorine. The disinfection effect showed that the inactivation rate with 2.0 mg/L of chloramine （90%） was higher than that with chlorine （70%）. Experimental results indicated that the high particle concentration in raw water and sedimentation effluent led to high levels of outflowing particles in the sand filter effluent. The activated carbon fines in the effluent accounted for a small proportion of the total particle amount, but the existing bacteria attached to carbon fines may influence the drinking water safety. The disinfection efficiency of desorbed bacteria was lower than that of free bacteria with chlorine, and the disinfection effect on bacteria attached to carbon fines with chloramine was better than that with only chlorine.
基金The National Key R&D Program of China under contract Nos 2016YFC1402104 and 2016YFC1402106the National Natural Science Foundation of China under contract No.41606190+2 种基金the Shandong Natural Science Foundation under contract No.ZR2016DB22the Foundation of Key Laboratory of Integrated Monitoring and Applied Technologies for Marine Harmful Algal Blooms,SOA under contract No.MATHAB 201806the Creative Team Project of the Laboratory for Marine Ecology and Environmental Science,Qingdao National Laboratory for Marine Science and Technology under contract No.LMEES-CTSP-2018-3
文摘Green tides caused by the unusual accumulation of high floating Ulva prolifera have occurred regularly in the Yellow Sea since 2007.The primary source of the Yellow Sea green tides is the attached algae on the Pyropia aquaculture rafts in the Subei Shoal.Ulva prolifera and Blidingia(Italic)sp.are the main species observed on Pyropia aquaculture rafts in the Subei Shoal.We found that U.prolifera has strong buoyancy and a rapid growth rate,which may explain why it is the dominant species of green tides that occur in the China's sea area of the Yellow Sea.The growth rate of floating U.prolifera was about 20%–31%d–1,which was much higher than Blidingia(Italic)sp.There were about 1.7×104 t of attached algae on the Pyropia aquaculture rafts in May 2012.We found that 39%of attached algae could float when the tide rose in the Subei Shoal,and U.prolifera accounted for 63%of the floating algae.Our analysis estimated that about 4000 t of attached U.prolifera floated into the surrounding waters of the Subei Shoal during the recycling period of aquaculture rafts.These results suggest that the initial floating biomass of large-scale green tides in the Yellow Sea is determined by the U.prolifera biomass attached to Pyropia aquaculture rafts,further impacting the scale of the green tide。
文摘Network attached storage (NAS) with the properties of improved scalability, simplified management, low cost and balanced price performance, is desirable for high performance storage systems applied to extensive areas. Unfortunately, it also has some disadvantages such as increased network workload, and inconvenience in disaster recovery. To overcome these disadvantages, we propose a channel bonding technique and provide hot backup functions in the designed NAS system, named HUSTserver. Channel bonding means merging multiple Ethernet channels into integrated one, and that the data packets can be transferred through any available network channels in a parallel mode. The hot backup function provides automatic data mirroring among servers. In this paper, we first describe the whole system prototype from a software and hardware architecture view. Then, multiple Ethernet and hot backup technologies that distinguish HUSTserver from others are discussed in detail. The findings presented demonstrate that network bandwidth can be scaled by the use of multiple commodity networks. Dual parallel channels of commodity 100 Mbps Ethernet are both necessary and sufficient to support the data rates of multiple concurrent file transfers. And the hot backup function introduced in our system provides high data accessibility.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences (Transformational Technologies for Clean Energy and Demonstration)(No.XDA21010211)the Shandong Provincial Natural Science Foundation (No.ZR2017QC007)the Youth Innovation Promotion Association, CAS。
文摘Attached cultivation is a promising method for microalgal biomass production. Filamentous oleaginous microalga Tribonema minus(hereafter T. minus) has shown a remarkable potential for biofuel production in terms of its high lipid content. However, the strain has only been cultivated in suspended cultivation systems including open pond and closed photobioreactors. Here, we attempted to study the attached cultivation of T. minus, which might be helpful for its scale-up cultivation and industrial applications. As the results, the optimal conditions for T. minus growth in the attached biofilm are 200 μmol photons m^-2 s^-1 of light intensity and 5% of CO2, and the maximum biomass density of 223 g m^-2 has been achieved under the light intensity. The non-woven fabric as substratum was found as the best substratum in thin layer attached bioreactor, on which the average biomass productivity of T. minus is about(9.73 ± 2.19) g m^-2)d^-1. Furthermore, two attached bioreactor systems, rotary drum and rotation disc, were designed following the light dilution strategy and introduced into T. minus cultivation. The highest footprint areal biomass productivity of these two systems is 33 and 47.1 g m^-2 d^-1, respectively, much higher than that in suspended cultivation system. The results shows that T. minus can be cultured with attached cultivation method to improve its biomass productivity.
文摘Cyclin B1 is a key regulatory protein controlling cell cycle progression in vertebrates. Cyclin B1 binds CDK1, a cy-clin-dependent kinase catalytic subunit, forming a complex that orchestrates mitosis through phosphorylation of key proteins. Cyclin B1 regulates both the activation of CDK1 and its subcellular localization, which may be critical for substrate selection. Here, we demonstrate that cyclin B1 is concentrated on the outer plate of the kinetochore during prometaphase. This localization requires the cyclin box region of the protein. Cyclin B1 is displaced from individual kinetochores to the spindle poles by microtubule attachment to the kinetochores, and this displacement is dependent on the dynein/dynactin complex. Depletion of cyclin B1 by vector-based siRNA causes inefficient attachment between kinetochores and microtubules, and chromosome alignment defects, and delays the onset of anaphase. We conclude that cyclin B1 accumulates at kinetochores during prometaphase, where it contributes to the correct attachment of mi- crotubules to kinetochores and efficient alignment of the chromosomes, most likely through localized phosphorylation of specific substrates by cyclin B1-CDK1. Cyclin B1 is then transported from each kinetochore as microtubule attachment is completed, and this relocalization may redirect the activity of cyclin B1-CDK1 and contribute to inactivation of the spindle assembly checkpoint.
文摘The stigma associated with the disease may be as subtle as avoidance,or dramatic as physical aggression.COVID-19 has begun to cause social disruption by growing disease-related stigma and xenophobia against some cultural,national,racial or religious groups worldwide.1 People of East Asian origin and those with facial features like them,or those with a travel history to areas affected by the outbreak,are especially being subjected to xenophobia in personal contact and online threats.COVID-19 has arisen as an unknown and newly emerged highly contagious infection that has spread rapidly across the globe and is associated with high mortality,leading to fear of encountering those infected.2 Leaders across the world have taken strict measures such as lockdowns and shutdown of various vital services that have caused chaos in people’s lives and increased concerns about the disease.3 Box 1 lists the factors leading to stigmatisation towards those infected with COVID-19.
基金This work was supported by National Science Foundation for Excellent Young Scholars,China(No.51722401)Key Project of National Natural Science Foundation,China(No.51734001)Fundamental Research Funds for the Central Universities(No.FRF-TP-18-003C1).
文摘Bacterial community dynamics and copper leaching with applied forced aeration were investigated during low-grade copper sulphide bioleaching to obtain better bioleaching efficiency.Results illustrated that appropriate aeration improved bacterial concentrations and leaching efficiencies.The highest bacterial concentration and Cu^(2+)concentration after 14-d leaching were 7.61×10^(7) cells·mL^(−1) and 704.9 mg·L^(−1),respectively,at aeration duration of 4 h·d^(−1).The attached bacteria played a significant role during bioleaching from 1 to 7 d.However,free bacteria dominated the bioleaching processes from 8 to 14 d.This phenomenon was mainly caused by the formation of passivation layer through Fe3+hydrolysis along with bioleaching,which inhibited the contact between the attached bacteria and ore.Meanwhile,16S rDNA analysis verified the effect of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans on the bioleaching process.The results demonstrate the importance of free and attached bacteria in bioleaching.
基金Project(31200382)supported by the National Natural Science Foundation of ChinaProject(2013FJ4068)supported by the Planned Science and Technology Project of Hunan Province,ChinaProject supported by Australia CSIRO OCE Science Leader Grant
文摘In order to investigate the effects of processing pH stimulation on bioleaching of chalcopyrite by moderate thermophiles,copper leaching rates and the dynamics of microbial community structures of free and attached cells were monitored. The results indicated that when the processing pH values were respectively adjusted to 1.0 and 3.0 on day 14, both free and attached cells experienced an adaptive phase. Meanwhile, the copper leaching rates were 86.9% and 64.0%,respectively, as opposed to a copper leaching rate of 87.5% in the control group without pH stimulation. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis suggested that pH stimulation imposed less impact on the attached organisms than on the free cells, indicating that the attached cells were more resistant to processing pH stimulation than the free cells. Furthermore, adjusting processing pH to 3.0 significantly disrupted both free and attached microbial communities, and the bioleaching system could not recover to the normal status as the control group.
基金supported by the Fundamental Research Funds for the Central Universities,China(No.NS2014092)。
文摘When non-cooperative body attachment occurs in space, the inertia of the new combination and the change of the system's momentum are unknown.This uncertainty may lead to the instability of the spacecraft's attitude control.In order to solve this problem, we propose an adaptive control scheme based on the inertia estimation of the new, combined system of non-cooperative body and satellite.This method can allow the new combination of different situations to reach a stable state with a high level of precision and speed.In this paper, the stability of the adaptive control scheme is proven by constructing a Lyapunov function.A simulation environment in which a non-cooperative body attaches to a satellite attaches to is constructed.The simulation shows that the attitude error converges to a small field when using the control scheme, regardless of unfavorable cases, including unknown inertia parameters, added momentum.In addition, the simulation results show the strong robustness of the control scheme for the new combination.
基金Projects(50574091,50774084) supported by the National Natural Science Foundation of China
文摘A feasible method to improve the reliability and processing efficiency of large vibrating screen via the application of an elastic screen surface with multiple attached substructures （ESSMAS） was proposed. In the ESSMAS, every screen rod, with ends embedded into elastomer, is coupled to the main screen structure in a relatively flexible manner. The theoretical analysis was conducted, which consists of establishing dynamic model promoted from the fuzzy structure theory as well as calculating for the equivalent stiffness of each attached structure. According to the numerical simulation using the NEWMARK-fl integration method, this assembling pattern significantly leads to the screen surface/rod having larger vibration intensity than that of the corresponding position on screen structure, which specifically, with an averaged acceleration amplitude increasing ratio of 11.37% in theoretical analysis and 20.27% in experimental test. The experimental results, within a tolerant error, also confirm the established model and demonstrate the feasibility of ESSMAS.
文摘Novel solid-contact perchlorate sensors based on cobalt phthalocyanine-C-monocarboxylic acid (I), and cobalt phthalocyanine-C,C,C,C-tetracarboxylic acid (II) as free ionophores and covalently attached to polyacryla- mide (PAA)—ionophores III and IV, respectively were prepared. The all solid-state sensors were constructed by the application of a thin film of a polymer cocktail containing a phthalocyanine ionophore and cetyltrimethylammonium bromide (CTMAB) as a lipophilic cationic additive onto a gold electrode precoated with the conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT) as an ion and electron transducer. The sensor with 10.3% of ionophore (III) covalently attached to plasticizer-free poly (butyl methacrylate-co-do- decyl methacrylate) (PBDA) exhibited a good selectivity for perchlorate and discriminated many ions, in- cluding F–, Cl–, Br–, I–, SCN–, , S2– and . The covalent attachment of the ionophore to the polymer resulted in a near-Nernstian anionic slope of –62.3 mV/decade whereas a super-Nernstian slope of –79.9 mV/ decade was obtained for the free ionophore. The sensor covered a linear concentration range of 5 × 10–9 - 1 × 10–2 mol?L–1 with a lower detection limit (LDL) of 1 × 10–9 mol?L–1 and gave a stable response over a pH range of 4 - 10.5. The all-solid state sensors were utilized for the selective flow injection potentiometric determination of perchlorate in natural water and human urine samples in the nanomolar concentration range.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 52171311 and 52271279)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (Grant No. 20KJB510046)。
文摘Numerical simulations of the non-spherical evolution of a pulsating bubble interacting with a stationary air bubble attached to a fixed structure were performed using a three-dimensional boundary integral method by implementing the mirror image method to simplify the processing of the numerical model. Code validation was accomplished by comparing the numerical results with the laboratory experimental data obtained in our previous study. Complex phenomena were observed, including three types of bubble jet forms, which depended strongly on the distance parameter with respect to the initial location of the bubble from the plate, the bubble strength parameter and the initial air bubble radius parameters. The results of the simulations provide detail insight into interesting bubble jetting phenomena,such as bubble splitting, jets moving away from the plate, and bubble shedding. The dimensionless distance parameter and the initial air bubble radius parameter play a major role in determining the shapes of two bubbles and the jetting direction. The air bubble strength parameter did not change the bubble jet direction but influenced the bubble shape.The detachment of the attached air bubble under oscillating bubble suction was easily observed for a small initial air bubble. These results showed that bubble jetting toward the plate was manipulated through the effect of attached air bubble, and that cavitation-based applications and underwater explosion bubble may benefit from this erosion mitigation approach.
文摘Inhalation of 222Rn progeny in the domestic environment contributes the greatest fraction of the natural radiation exposure to the public. The ultrafine activity of these progeny amounts up to about l 0 percent of the total activity （attached and ultrafine）, but is considered to yield about 50 percent of the total radiation dose. Therefore, measurements of ultrafine fraction are essential for the estimation of radiation dose. The current study presents measured data on the total equilibrium equivalent concentration （EEC） and ultrafine equilibrium equivalent concentration （EECUn）, ultrafine fraction （fb）, attached and unattached activity size distributions of radon progeny in the low ventilated rooms at Minia University, Minia city, Egypt. A screen diffusion battery was used for collection the ultrafine fraction and measuring the total activity concentration of radon progeny. The attached activity size distribution of 214pb is determined by using a low pressure cascade impactor. The EEC of radon progeny varied between 1.3 and 18.9 Bq/m3 with a mean value of 5.2 ± 0.48 Bq/m2. The mean activity thermodynamic diameter （AMTD） ofultrafine of radon progeny was determined to be 1.26 nm with relative mean geometric standard deviations （GSD） of 1.3. The ultrafine fraction of radon progeny, fb, has a range 0.01 to 0.21 with an average of 0.08 ± 0.03. A relative mean GSD of 2.7 was determined for attached 2Lapb at a mean active median aerodynamic diameter （AMD） of 350 nm. Based on the above experimental results, the deposition fractions have been evaluated in each air way generation through the human lung by applying a lung deposition model. The bronchial deposition efficiencies of particles in the size range of attached radon progeny were found to be lower than those of ultrafine progeny. The effect of radon progeny deposition by adult male has been also studied for various levels of physical exertion. The dose conversion factor has been discussed as a function of fb.
文摘An algorithm is presented to analyze the free vibration in a system composed of a cable with discrete elements, e.g., a concentrated mass, a translational spring, and a harmonic oscillator. The vibrations in the cable are modeled and analyzed with the Lagrange multiplier formalism. Some fragments of the investigated structure are modeled with continuously distributed parameters, while the other fragments of the structure are modeled with discrete elements. In this case, the linear model of a cable with a small sag serves as a continuous model, while the elements, e.g., a translational spring, a concentrated mass, and a harmonic oscillator, serve as the discrete elements. The method is based on the analytical solutions in relation to the constituent elements, which, when once derived, can be used to formulate the equations describing various complex systems compatible with an actual structure. The numerical analysis shows that, the method proposed in this paper can be successfully used to select the optimal parameters of a system composed of a cable with discrete elements, e.g., to detune the frequency resonance of some structures.
