The aim of this study is to develop magnetopolymer composites suitable for fabricating soft magnetoactive robots via extrusion-based3D printing.Polysiloxane copolymers with urea fragments were synthesized and characte...The aim of this study is to develop magnetopolymer composites suitable for fabricating soft magnetoactive robots via extrusion-based3D printing.Polysiloxane copolymers with urea fragments were synthesized and characterized,and their thermophysical and rheological properties were investigated.This study provides an assessment of the potential for their further use in additive manufacturing.The obtained materials were utilized as matrices for creating magnetically active polymer composites by incorporating microparticles of carbonyl iron.Samples of complex geometries were printed using both neat and filled filaments,demonstrating the feasibility of employing these materials in extrusion-based 3D printing.展开更多
Enzyme-powered micro/nanomotors(MNMs)(EMNMs)use natural enzymes to facilitate the decomposition of fuels,including hydrogen peroxide(H2O2),glucose,triglycerides,and urea to provide power.EMNMs can achieve self-propuls...Enzyme-powered micro/nanomotors(MNMs)(EMNMs)use natural enzymes to facilitate the decomposition of fuels,including hydrogen peroxide(H2O2),glucose,triglycerides,and urea to provide power.EMNMs can achieve self-propulsion through the in situ utilization of biofuels without additional fuels,exhibiting excellent biocompatibility and significant potential for application in the biomedical field.Compared with H_(2)O_(2),which may cause oxidative damage to the body,urea exhibits superior biosafety characteristics.Presently,urease-powered MNMs(UMNMs)have made notable progress in their applications in the biomedical field and have garnered considerable attention from researchers.In this review,we present the latest advancements in the biomedical field of UMNMs,primarily focusing on:1)diverse materials used for constructing the fundamental framework of motors;2)control of motor movement through the regulation of enzymatic reaction rates;and 3)research directions for the clinical application of motors,including in vivo imaging,biomarker detection,cancer treatment,optical therapy,overcoming biological barriers,antibacterial interventions,antithrombotic strategies,and gastric disease management.Despite showing immense potential in biomedical applications,there are still several challenges impeding its practical implementation,such as maintaining activity in the in vivo environment while accurately targeting specific sites to achieve the desired clinical therapeutic effects.展开更多
This paper presents a microdevice developed to measure the electrical conductivity of a liquid or a saturated porous medium using Wenner method.It is developed in the context of biocementation as soil improvement tech...This paper presents a microdevice developed to measure the electrical conductivity of a liquid or a saturated porous medium using Wenner method.It is developed in the context of biocementation as soil improvement technique,which is used in Civil Engineering applications to produce calcium carbonate through bacterial or enzymatic activity,replacing the use of other binder materials such as cement or resins,and therefore reducing carbon footprint.The microdevice was used to measure urease activity in the soil interstitial fluid,to investigate if bacterial activity could be affected by the presence of the particles and tortuosity from pore geometry.Such analysis is important to understand biocementation mechanism inside the soil and helps to improve the design of such treatment solutions.The device is basically a squared reservoir printed in polypropylene using a 3D printing machine,incorporating stainless steel electrodes in its base.The electrical resistivity was computed adopting Wenner method,by connecting 4 PCB electrodes to a signal generator and an oscilloscope for measuring the voltage when a AC current of 1 mA was applied.Both square and sinusoidal waves with 5 kHz frequency were selected among other frequencies.The measurements were adjusted during the calibration of the microdevice,done using standard salt solutions with known electrical conductivity measured using an electrical conductivity probe.For the bacterial activity measurements,the bacterial and urea solutions were added to a uniform-graded size quarzitic sand(average diameter 0.3 mm)placed inside the microdevice and covering completely the electrodes.Bacterial activity was not affected by the presence of the sand,which confirms that this treatment is effective for this type of soils.展开更多
Biomineralization based on bacterial enzyme induced carbonate precipitation(BEICP)process is a promising alternative to cement-based ground treatment technology.The bacterial urease used in BEICP process is usually ul...Biomineralization based on bacterial enzyme induced carbonate precipitation(BEICP)process is a promising alternative to cement-based ground treatment technology.The bacterial urease used in BEICP process is usually ultrasonic extracted from urease-producing bacteria.To efficiently extract urease with relatively higher activity from bacterial cells,the ultrasonic extraction parameters of urease were optimized in this study.Next,a series of bacterial urease extraction tests and sand column treatment tests were conducted to investigate the effects of vibration amplitude,upper temperature limit,and cooling method on the urease extraction process and biomineralization of sand.The results show that the upper temperature limit is an important factor affecting the extraction efficiency and the activity of the extracted urease solution,and the optimum upper temperature limit is 50℃.The results indicate that increasing vibration amplitude could improve the extraction efficiency,but it hardly affects the urease activity(UA)under the optimal temperature.Continuous cooling could effectively simplify the operation and further improve the efficiency of urease extraction.Under the same urease activity of biotreatment solution,there is no marked difference in calcium carbonate content(CCC)and unconfined compressive strength of biomineralized sand columns prepared by urease solution extracted with different vibration amplitudes and upper temperature limits.The results of this study could provide a reference for application of BEICP technology of urease extraction to large-scale soil treatment.展开更多
This study explores the adaptation of microbial enzymatic techniques,which were originally developed to eliminate amino impurities in alcoholic beverages,for stabilizing strongly alkaline sodium-based dispersive soils...This study explores the adaptation of microbial enzymatic techniques,which were originally developed to eliminate amino impurities in alcoholic beverages,for stabilizing strongly alkaline sodium-based dispersive soils from check dams.Employing acid urease from Lactobacillus reuteri(L.reuteri)and a control group using soybean-derived urease,this research aimed to modify soil alkalinity through biomineralization.Ultraviolet(UV)mutagenesis optimized L.reuteri strains for biomass and activity.Solution experiments were conducted to assess the effects of pH,temperature,and storage duration on urease activity and to evaluate the calcium carbonate production and crystal morphology of the two ureases under varying calcium ion concentrations.Dispersivity identificationtests and tensile strength evaluations were conducted to analyze the disparities in the modifieddispersive soil treated with the two types of ureases.The results showed that soybean urease should be stored under low-temperature conditions and a neutral pH,whereas acid urease from L.reuteri can be stored at room temperature across a range of pH levels.Both urease treatments effectively reduced soil dispersivity and improved tensile strength significantly(up to 94%and 177%,respectively),with acid urease from L.reuteri resulting in superior soil strengthening and ammonia regulation.These findingssuggest that treating alkaline dispersive soils with acid urease is an efficientand eco-friendly method.展开更多
[Objective]The activities of urease and phosphatase in integrated vertical flow constructed wetland and purification effect of black and malodorous river were studied.[Method]Honeycomb stone and soft filler were used ...[Objective]The activities of urease and phosphatase in integrated vertical flow constructed wetland and purification effect of black and malodorous river were studied.[Method]Honeycomb stone and soft filler were used as matrix,the biological grid integrated vertical flow constructed wetland system was built to strengthen treatment for black and malodorous river,and the activities of urease and phosphatase of two fillers in different functional areas of constructed wetland were tested to study the film formation property of two fillers in different functional areas.[Result]Both urease and phosphatase activities on biofilm of soft filler were significantly higher than on biofilm of honeycomb stone filler;indicating that choosing soft filler was more advantageous to the growth of biofilm;and urease activity had significant correlation with total nitrogen removal rate,while phosphatase activity had no significant correlation with total phosphorus removal rate.[Conclusion]This study provided evidences for utilizing the activities of urease and phosphatase to evaluate the purification effect of black and malodorous river and choose appropriate filler.展开更多
[Object] The study aimed to supply a reference for evaluating ecotoxicology of soil contaminated with phthalate acid esters(PAEs).[Method] The dynamic effects of DBP and DEHP on activities and kinetics parameters of u...[Object] The study aimed to supply a reference for evaluating ecotoxicology of soil contaminated with phthalate acid esters(PAEs).[Method] The dynamic effects of DBP and DEHP on activities and kinetics parameters of urease and phosphatase in agro-soil contaminated artificially with DBP and DEHP were studied.[Result] The activities of urease and phosphatase were both inhibited significantly by higher contents of DBP and DEHP in soils compared with CK.The inhabitations increased with increasing DBP and DEHP c...展开更多
Two Co(Ⅱ)and Ni(Ⅱ)complexes were synthesized by synergistic coordination of 3,3-diphenylpropionic acid(HDPA)and 2,2′-bipyridylamine(PAm).The structures of complexes[Co(DPA)_(2)(PAm)]·2H_(2)O(1)and[Ni(DPA)_(2)(...Two Co(Ⅱ)and Ni(Ⅱ)complexes were synthesized by synergistic coordination of 3,3-diphenylpropionic acid(HDPA)and 2,2′-bipyridylamine(PAm).The structures of complexes[Co(DPA)_(2)(PAm)]·2H_(2)O(1)and[Ni(DPA)_(2)(PAm)]·2H_(2)O(2)were determined by single-crystal X-ray diffraction,IR spectroscopy,and powder X-ray diffraction.Hirshfeld surface analysis provided quantitative insights into the intermolecular interactions within the complexes,while molecular docking studies elucidated their binding modes and affinities toward urease.Furthermore,the biological activities of both complexes were systematically evaluated through a range of assays,including DNA binding,urease inhibition,antibacterial activity,and in vitro cytotoxicity against cancer cells.Both complexes exhibited binding affinity for DNA and displayed notable urease inhibitory activity.Under in vitro conditions,both complexes showed appreciable cytotoxicity toward HepG2 cells with efficacy comparable to clinically used platinumbased anticancer agents.CCDC:2479943,1;2479944,2.展开更多
The reaction of isocyanates with aliphatic and aromatic amines in the 1-n-butyl-3- methylimidazolium tetrafluoroborate (bmimBF4) ionic liquid in good to excellent yields is described. Due to its insolubility, the des...The reaction of isocyanates with aliphatic and aromatic amines in the 1-n-butyl-3- methylimidazolium tetrafluoroborate (bmimBF4) ionic liquid in good to excellent yields is described. Due to its insolubility, the desired urea solids could be recovered by simple filtration from the ionic liquid after reaction.展开更多
The aim of this research was to synthesize a new totally bio wood adhesive entailing the use of oxidized starch(OST),urea,and oxidized lignin(OL).For this reason,non-modified(L)and oxidized lignin(OL)at different cont...The aim of this research was to synthesize a new totally bio wood adhesive entailing the use of oxidized starch(OST),urea,and oxidized lignin(OL).For this reason,non-modified(L)and oxidized lignin(OL)at different contents(20%,30%,and 40%)were used to prepare the starch-urea-lignin(SUL)and starch-urea-oxidized lignin(SUOL)resin.Sodium persulfate(SPS)as oxidizer was employed to oxidize both starch and lignin.Urea was just used as a low cost and effective crosslinker in the resin composition.The properties of the synthesized resins and the plywood panels bonded with themweremeasured according to relevant standards.The viscosity and gel time of the SUOL resins containing oxidized lignin are respectively higher and faster than for non-modified lignin(SUL).The lignin phenolic hydroxyl groups(-OH)proportion was markedly increased by oxidation as shown by Fourier Transform Infrared(FTIR)spectrometry.The molecular mass and the polydispersity of the lignin did also decrease by its oxidization pretreatment.DSC analysis showed a decrease of the glass transition temperature of the lignin(Tg)due to its oxidation.The thermal analysis of the oxidized lignin SUOL resin also showed that it had a lower peak temperature than the SUL equivalent non-modified lignin resin.The plywood panels bonded with oxidized lignin gave acceptable bending modulus,bending strength,peak temperature by thermal analysis and dry shear strength as well as a better plywood dimensional stability when used in the SUOL formulation.The synthesized SUOL adhesive is a lignin-derived,totally bio,no-aldehyde added,inexpensive resin applicable to bond plywood.展开更多
Dear Editor,Urea is a vital nitrogen(N)fertilizer in farmland soils and the natural intermediate product of various organonitrogen compounds,such as purines and amino acids(Mobley and Hausinger,1989;Glibert et al.,201...Dear Editor,Urea is a vital nitrogen(N)fertilizer in farmland soils and the natural intermediate product of various organonitrogen compounds,such as purines and amino acids(Mobley and Hausinger,1989;Glibert et al.,2014).Urea in soils is rapidly hydrolyzed to ammonium by urease secreted from ureolytic microorganisms,and then assimilated by plants and microbes or involved in other N cycling pathways,including aerobic and anaerobic ammoxidation(Mobley et al.,1995;Pajares and Bohannan,2016).展开更多
基金financially supported by the Russian Science Foundation(No.23-43-00057)the International Cooperation Program of the Natural Science Foundation of China(No.52261135542)。
文摘The aim of this study is to develop magnetopolymer composites suitable for fabricating soft magnetoactive robots via extrusion-based3D printing.Polysiloxane copolymers with urea fragments were synthesized and characterized,and their thermophysical and rheological properties were investigated.This study provides an assessment of the potential for their further use in additive manufacturing.The obtained materials were utilized as matrices for creating magnetically active polymer composites by incorporating microparticles of carbonyl iron.Samples of complex geometries were printed using both neat and filled filaments,demonstrating the feasibility of employing these materials in extrusion-based 3D printing.
基金supported by the National Natural Science Foundation of China(Grant No.:82372102).
文摘Enzyme-powered micro/nanomotors(MNMs)(EMNMs)use natural enzymes to facilitate the decomposition of fuels,including hydrogen peroxide(H2O2),glucose,triglycerides,and urea to provide power.EMNMs can achieve self-propulsion through the in situ utilization of biofuels without additional fuels,exhibiting excellent biocompatibility and significant potential for application in the biomedical field.Compared with H_(2)O_(2),which may cause oxidative damage to the body,urea exhibits superior biosafety characteristics.Presently,urease-powered MNMs(UMNMs)have made notable progress in their applications in the biomedical field and have garnered considerable attention from researchers.In this review,we present the latest advancements in the biomedical field of UMNMs,primarily focusing on:1)diverse materials used for constructing the fundamental framework of motors;2)control of motor movement through the regulation of enzymatic reaction rates;and 3)research directions for the clinical application of motors,including in vivo imaging,biomarker detection,cancer treatment,optical therapy,overcoming biological barriers,antibacterial interventions,antithrombotic strategies,and gastric disease management.Despite showing immense potential in biomedical applications,there are still several challenges impeding its practical implementation,such as maintaining activity in the in vivo environment while accurately targeting specific sites to achieve the desired clinical therapeutic effects.
基金FCT I.P,for the funding through CALCITE Project(ref.PTDC/ECI-EGC/1086/2021).
文摘This paper presents a microdevice developed to measure the electrical conductivity of a liquid or a saturated porous medium using Wenner method.It is developed in the context of biocementation as soil improvement technique,which is used in Civil Engineering applications to produce calcium carbonate through bacterial or enzymatic activity,replacing the use of other binder materials such as cement or resins,and therefore reducing carbon footprint.The microdevice was used to measure urease activity in the soil interstitial fluid,to investigate if bacterial activity could be affected by the presence of the particles and tortuosity from pore geometry.Such analysis is important to understand biocementation mechanism inside the soil and helps to improve the design of such treatment solutions.The device is basically a squared reservoir printed in polypropylene using a 3D printing machine,incorporating stainless steel electrodes in its base.The electrical resistivity was computed adopting Wenner method,by connecting 4 PCB electrodes to a signal generator and an oscilloscope for measuring the voltage when a AC current of 1 mA was applied.Both square and sinusoidal waves with 5 kHz frequency were selected among other frequencies.The measurements were adjusted during the calibration of the microdevice,done using standard salt solutions with known electrical conductivity measured using an electrical conductivity probe.For the bacterial activity measurements,the bacterial and urea solutions were added to a uniform-graded size quarzitic sand(average diameter 0.3 mm)placed inside the microdevice and covering completely the electrodes.Bacterial activity was not affected by the presence of the sand,which confirms that this treatment is effective for this type of soils.
基金the National Natural Science Foundation of China(NSFC)(Grant Nos.52108307 and 52178319)the Natural Science Foundation of Fujian Province,China(Grant No.2022J05020).
文摘Biomineralization based on bacterial enzyme induced carbonate precipitation(BEICP)process is a promising alternative to cement-based ground treatment technology.The bacterial urease used in BEICP process is usually ultrasonic extracted from urease-producing bacteria.To efficiently extract urease with relatively higher activity from bacterial cells,the ultrasonic extraction parameters of urease were optimized in this study.Next,a series of bacterial urease extraction tests and sand column treatment tests were conducted to investigate the effects of vibration amplitude,upper temperature limit,and cooling method on the urease extraction process and biomineralization of sand.The results show that the upper temperature limit is an important factor affecting the extraction efficiency and the activity of the extracted urease solution,and the optimum upper temperature limit is 50℃.The results indicate that increasing vibration amplitude could improve the extraction efficiency,but it hardly affects the urease activity(UA)under the optimal temperature.Continuous cooling could effectively simplify the operation and further improve the efficiency of urease extraction.Under the same urease activity of biotreatment solution,there is no marked difference in calcium carbonate content(CCC)and unconfined compressive strength of biomineralized sand columns prepared by urease solution extracted with different vibration amplitudes and upper temperature limits.The results of this study could provide a reference for application of BEICP technology of urease extraction to large-scale soil treatment.
基金financiallysupported by the National Natural Science Foundation of China(Grant Nos.52079116,52108343,and 51579215).
文摘This study explores the adaptation of microbial enzymatic techniques,which were originally developed to eliminate amino impurities in alcoholic beverages,for stabilizing strongly alkaline sodium-based dispersive soils from check dams.Employing acid urease from Lactobacillus reuteri(L.reuteri)and a control group using soybean-derived urease,this research aimed to modify soil alkalinity through biomineralization.Ultraviolet(UV)mutagenesis optimized L.reuteri strains for biomass and activity.Solution experiments were conducted to assess the effects of pH,temperature,and storage duration on urease activity and to evaluate the calcium carbonate production and crystal morphology of the two ureases under varying calcium ion concentrations.Dispersivity identificationtests and tensile strength evaluations were conducted to analyze the disparities in the modifieddispersive soil treated with the two types of ureases.The results showed that soybean urease should be stored under low-temperature conditions and a neutral pH,whereas acid urease from L.reuteri can be stored at room temperature across a range of pH levels.Both urease treatments effectively reduced soil dispersivity and improved tensile strength significantly(up to 94%and 177%,respectively),with acid urease from L.reuteri resulting in superior soil strengthening and ammonia regulation.These findingssuggest that treating alkaline dispersive soils with acid urease is an efficientand eco-friendly method.
基金Supported by National Major Science and Technology Projects(2009ZX07317-006)National Major Science and Technology Projects(2009ZX07317-009)~~
文摘[Objective]The activities of urease and phosphatase in integrated vertical flow constructed wetland and purification effect of black and malodorous river were studied.[Method]Honeycomb stone and soft filler were used as matrix,the biological grid integrated vertical flow constructed wetland system was built to strengthen treatment for black and malodorous river,and the activities of urease and phosphatase of two fillers in different functional areas of constructed wetland were tested to study the film formation property of two fillers in different functional areas.[Result]Both urease and phosphatase activities on biofilm of soft filler were significantly higher than on biofilm of honeycomb stone filler;indicating that choosing soft filler was more advantageous to the growth of biofilm;and urease activity had significant correlation with total nitrogen removal rate,while phosphatase activity had no significant correlation with total phosphorus removal rate.[Conclusion]This study provided evidences for utilizing the activities of urease and phosphatase to evaluate the purification effect of black and malodorous river and choose appropriate filler.
基金Supported by the Blue Project of Jiangsu ProvinceNatural Science Foundation of Huai an(SN0777)+1 种基金the Development Project of Jiangsu Key Laboratory for Eco-Agricultural Biotechnology around HongzeLake(HZHL0813)Natural Science Foundation of Huaiyin Institute of Technology(351707077)~~
文摘[Object] The study aimed to supply a reference for evaluating ecotoxicology of soil contaminated with phthalate acid esters(PAEs).[Method] The dynamic effects of DBP and DEHP on activities and kinetics parameters of urease and phosphatase in agro-soil contaminated artificially with DBP and DEHP were studied.[Result] The activities of urease and phosphatase were both inhibited significantly by higher contents of DBP and DEHP in soils compared with CK.The inhabitations increased with increasing DBP and DEHP c...
文摘Two Co(Ⅱ)and Ni(Ⅱ)complexes were synthesized by synergistic coordination of 3,3-diphenylpropionic acid(HDPA)and 2,2′-bipyridylamine(PAm).The structures of complexes[Co(DPA)_(2)(PAm)]·2H_(2)O(1)and[Ni(DPA)_(2)(PAm)]·2H_(2)O(2)were determined by single-crystal X-ray diffraction,IR spectroscopy,and powder X-ray diffraction.Hirshfeld surface analysis provided quantitative insights into the intermolecular interactions within the complexes,while molecular docking studies elucidated their binding modes and affinities toward urease.Furthermore,the biological activities of both complexes were systematically evaluated through a range of assays,including DNA binding,urease inhibition,antibacterial activity,and in vitro cytotoxicity against cancer cells.Both complexes exhibited binding affinity for DNA and displayed notable urease inhibitory activity.Under in vitro conditions,both complexes showed appreciable cytotoxicity toward HepG2 cells with efficacy comparable to clinically used platinumbased anticancer agents.CCDC:2479943,1;2479944,2.
文摘The reaction of isocyanates with aliphatic and aromatic amines in the 1-n-butyl-3- methylimidazolium tetrafluoroborate (bmimBF4) ionic liquid in good to excellent yields is described. Due to its insolubility, the desired urea solids could be recovered by simple filtration from the ionic liquid after reaction.
基金funded by Semnan University,research grant No.226/1403/T140211.
文摘The aim of this research was to synthesize a new totally bio wood adhesive entailing the use of oxidized starch(OST),urea,and oxidized lignin(OL).For this reason,non-modified(L)and oxidized lignin(OL)at different contents(20%,30%,and 40%)were used to prepare the starch-urea-lignin(SUL)and starch-urea-oxidized lignin(SUOL)resin.Sodium persulfate(SPS)as oxidizer was employed to oxidize both starch and lignin.Urea was just used as a low cost and effective crosslinker in the resin composition.The properties of the synthesized resins and the plywood panels bonded with themweremeasured according to relevant standards.The viscosity and gel time of the SUOL resins containing oxidized lignin are respectively higher and faster than for non-modified lignin(SUL).The lignin phenolic hydroxyl groups(-OH)proportion was markedly increased by oxidation as shown by Fourier Transform Infrared(FTIR)spectrometry.The molecular mass and the polydispersity of the lignin did also decrease by its oxidization pretreatment.DSC analysis showed a decrease of the glass transition temperature of the lignin(Tg)due to its oxidation.The thermal analysis of the oxidized lignin SUOL resin also showed that it had a lower peak temperature than the SUL equivalent non-modified lignin resin.The plywood panels bonded with oxidized lignin gave acceptable bending modulus,bending strength,peak temperature by thermal analysis and dry shear strength as well as a better plywood dimensional stability when used in the SUOL formulation.The synthesized SUOL adhesive is a lignin-derived,totally bio,no-aldehyde added,inexpensive resin applicable to bond plywood.
基金supported by the Funds for International Cooperation and Exchange of the National Natural Science Foundation of China(No.42020104003)。
文摘Dear Editor,Urea is a vital nitrogen(N)fertilizer in farmland soils and the natural intermediate product of various organonitrogen compounds,such as purines and amino acids(Mobley and Hausinger,1989;Glibert et al.,2014).Urea in soils is rapidly hydrolyzed to ammonium by urease secreted from ureolytic microorganisms,and then assimilated by plants and microbes or involved in other N cycling pathways,including aerobic and anaerobic ammoxidation(Mobley et al.,1995;Pajares and Bohannan,2016).
