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
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 induced carbonate precipitation(EICP)is a promising technique in the field of biocementation due to its efficiency and controllability.Although many studies have proved its reliability in different environment,...Enzyme induced carbonate precipitation(EICP)is a promising technique in the field of biocementation due to its efficiency and controllability.Although many studies have proved its reliability in different environment,little attention has been paid to the influence of humic substances on the EICP.Humic substances cover most of the surface soil across the world land with vegetation,which varies according to the density of vegetation and climate.To understand the compatibility of this technique to distinct problematic soils,it is important to figure out how humic substances could affect the carbonate precipitation process induced by urease enzyme.Therefore,this study aims to investigate the effects of humic acid(HA),one type of humic substance,on the soil solidification through EICP.For this purpose,HA was added to natural soil with varying addition amounts(0%,1%,2%,4%,8%,16%)in soil column solidification tests.The results found that the cementation effectiveness was enhanced by a small amount of HA addition(<4%),while an addition up to 8%greatly inhibited the formation of calcium carbonate.At the same time,soil samples were buffered by HA in a weak acidic condition,thus preventing the emission of undesirable by-product ammonia in the ureolysis process.Therefore,this study makes a contribution to research on enzymatic biocementation by demonstrating the effects of HA on the cementation effectiveness of EICP technique.展开更多
[Objective] The aim was to study on effects of "straw returning and ir-returning" and "irrigation with ground water and water in the Yellow River" on changes of enzyme activity in soils under wheat...[Objective] The aim was to study on effects of "straw returning and ir-returning" and "irrigation with ground water and water in the Yellow River" on changes of enzyme activity in soils under wheat at different developmental stages. [Method] Jimai 22, a kind of winter wheat, was made use of in fields to study on effects of "straw returning and ir-returning" and "irrigation with ground water and water in the Yellow River" on changes of enzyme activity in soils under wheat in different developmental stages. [Result] With advancement of developmental stage, urease activity of wheat in the four groups all showed the trend of "increasing-decreasing-increasing" and activities of invertase and phosphatase both changed from increasing to decreasing. In addition, urease activities of soils in wheat roots were improved by straw returning in four developmental stages. Meanwhile, activity of soil enzyme was better promoted by irrigation with ground water than with water in the Yellow River, except in grain-filling stage. Before developmental stage, different processing methods had a significant effect on phosphatase activity, for example, straw returning and ground water significantly enhanced activities of two kinds of phosphatase and promoted P absorption and transferring by plants and microorganisms in jointing stage; activity of acid phosphatase was higher in the group where irrigation with ground water and straw returning were adopted than those in the rest three groups in booting stage. [Conclusion] The research laid a foundation for dynamic relationship among activity of soil enzyme, crop growth and microorganisms.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
AIM: To investigate the association of colorectal adenomas with both Helicobacter pylori (H. pylori) infection and metabolic syndrome. METHODS: Using a cross-sectional hospital-based study, we analyzed physical examin...AIM: To investigate the association of colorectal adenomas with both Helicobacter pylori (H. pylori) infection and metabolic syndrome. METHODS: Using a cross-sectional hospital-based study, we analyzed physical examination data from 9311 healthy subjects with overnight physical examinations performed between January 2004 and December 2006. Examined data included gender, age, life style, anthropometric measurements, blood pressure, biochemical and hematological studies, H. pylori infection detected by esophagogastroduodenoscopy and biopsy urease tests, and colorectal adenomas detected with a complete total colonoscopy. RESULTS: The prevalence values for H. pylori infection, metabolic syndrome, and colorectal adenoma were39.2%, 18.7%, and 20.7%, respectively. Colorectal adenoma risk factors included male gender [odd ratio (OR): 2.005, 95% conf idence interval (CI): 1.740-2.310, P < 0.001], advanced age (OR: 1.046, 95% CI: 1.040-1.052, P < 0.001), smoking (OR: 1.377, 95% CI: 1.146-1.654, P = 0.001), increased body fat (OR: 1.016, 95% CI: 1.007-1.026, P = 0.001), higher white blood cell count (OR: 1.038, 95% CI: 1.005-1.073, P = 0.025), H. pylori infection (OR: 1.366, 95% CI: 1.230-1.517, P < 0.001), and metabolic syndrome (OR: 1.408, 95% CI: 1.231-1.610, P < 0.001). In addition, concomitant H. pylori infection with metabolic syndrome further increased the probability of colorectal adenomas. CONCLUSION: Our study revealed H. pylori infection with concomitant metabolic syndrome might further increase the risk of colorectal adenomas.展开更多
Over the past several years, the severity of Helicobacter pylori(H. pylori) infections has not significantly diminished. After successful eradication, the annual H. pylori recurrence rate is approximately 13% due toor...Over the past several years, the severity of Helicobacter pylori(H. pylori) infections has not significantly diminished. After successful eradication, the annual H. pylori recurrence rate is approximately 13% due tooral H. pylori infection. Established clinical diagnostic techniques do not identify an oral etiologic basis of H. pylori prior to gastric infection. There has been disagreement as to whether oral infection of H. pylori exists or not, with no definite conclusion. In medical practice, negative results with the urea breath test suggest that the stomach infection of H. pylori is cured in these patients. In fact, patients can present negative urea breath test results and yet exhibit H. pylori infection due to oral infection. The present paper provides evidence that H. pylori oral infection is nonetheless present, and the oral cavity represents a secondary site for H. pylori colonization.展开更多
The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentratio...The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.展开更多
The term gastrointestinal stromal tumors （GISTs） is defined diagnostically as the main group of mesenchymal tumors with spindle or epithelioid cells arising from the wall of the gastrointestinal tract with immunohis...The term gastrointestinal stromal tumors （GISTs） is defined diagnostically as the main group of mesenchymal tumors with spindle or epithelioid cells arising from the wall of the gastrointestinal tract with immunohistochemical reactivity for CD117 antibody. Previous studies revealed that cells in GISTs express a growth factor receptor with tyrosine kinase activity （termed c-kit）, which is the product of the c-kit protooncogene. The most specific and practical diagnostic criteria for GISTs are： immunohistochemically determined c-kit （CD117） expression; mitotic score; and tumor size. A small GIST concomitant with early gastric cancer is rarely encountered clinically. Herein we have reported a case of a 1.1-cm GIST detected by esophagogastroduo denoscopy concomitant with a IIc type of early gastric cancer （signet ring cell type）. It was detected during a routine physical health examination. To our knowledge, this is the first report of a small GIST concomitant with a signet ring cell type of early gastric cancer.展开更多
Individual and combined effects of Cu, Pb, Zn and Cd on N mineralization, urease and phosphatase were examined in a Typic Udic Ferrisol in laboratory by employing an uniform design and a single factor design.Soil poll...Individual and combined effects of Cu, Pb, Zn and Cd on N mineralization, urease and phosphatase were examined in a Typic Udic Ferrisol in laboratory by employing an uniform design and a single factor design.Soil pollution caused by heavy metals inhibited N mineralization (No value) and urease and phosphatase activities. The combined pollution of metals alleviated their toxicity to N mineralization to some extent,whereas aggravated the toxicity to urease and phosphatase. Phosphorous application could mitigate the toxic effect of heavy metals on phosphatase activities, while alleviating effect of N application on the toxicity of heavy metals to urease was inconsistent. However, the mitigating effect of the fertilizers was limited in heavily polluted soils.展开更多
Due to frequent soil Cd contamination and wide use of butachlor in China,there is a need to assess their combined toxicity to soil microorganisms.The combined effects of cadmium(Cd,10 mg kg-1 soil) and herbicide butac...Due to frequent soil Cd contamination and wide use of butachlor in China,there is a need to assess their combined toxicity to soil microorganisms.The combined effects of cadmium(Cd,10 mg kg-1 soil) and herbicide butachlor(10,50,and 100 mg kg-1 soil) on enzyme activities and microbial community structure in a paddy soil were assessed using the traditional enzyme assays and random amplified polymorphic DNA(RAPD) analysis.The results showed that urease and phosphatase activities were significantly reduced by high butachlor concentration(100 mg kg-1 soil).When the concentrations of Cd and butachlor added were at a ratio of 1:10,urease and phosphatase activities were significantly decreased whereas enzyme activities were greatly improved at the ratio of 1:5,which indicated that the combined effects of Cd and butachlor on soil urease and phosphatase activities depended largely on their addition concentration ratios.Random amplified polymorphic DNA(RAPD) analysis showed loss of original bands and appearance of new bands when compared with the control soil.Random amplified polymorphic DNA fingerprints suggested substantial differences between the control and treated soil samples,with apparent changes in the number and size of amplified DNA fragments.The addition of high concentration butachlor and the combined impacts of Cd and butachlor significantly affected the diversity of the microbial community.RAPD analysis in conjunction with other biomarkers such as soil enzyme parameters would prove a powerful ecotoxicological tool.Further investigations should be carried out to understand the clear link between RAPD patterns and enzyme activity.展开更多
To increase fertilizer use efficiency （FUE） and to minimize its negative impact on environment have been the focal points in the world for a long time. It is very important to increase FUE in China for its relativel...To increase fertilizer use efficiency （FUE） and to minimize its negative impact on environment have been the focal points in the world for a long time. It is very important to increase FUE in China for its relatively low FUE and serious losses of nutrients. Recent advances of the technologies to increase FUE are reviewed in this article. These include site-specific and real-time nitrogen management, non-destructive quick test of the nitrogen status of plants, new types of slow release and controlled release fertilizers, site-specific nutrient management, and use of urease inhibitor and nitrification inhibitor to decrease nitrogen losses. Future outlook in technologies related to FUE improvement is also discussed.展开更多
AIM:To evaluate the influence of multiple samplings during esophagogastr oduodenoscopy(EGD) on the accuracy of the rapid urease test,and the validity of newly developed rapid urease tests,HelicotecUT plus test and Hel...AIM:To evaluate the influence of multiple samplings during esophagogastr oduodenoscopy(EGD) on the accuracy of the rapid urease test,and the validity of newly developed rapid urease tests,HelicotecUT plus test and HelicotecUT test,CLO test and ProntoDry test.METHODS:A total of 355 patients undergoing EGD for dyspepsia were included.Their Helicobacter pylori(H.pylori) treatment status was either nave or eradicated.Six biopsy specimens from antrum and gastric body,respectively,were obtained during EGD.Single antral specimens and dual(antrum+body) specimens were compared.Infection status of H.pylori was evaluated by three different tests:culture,histology,and four different commercially available rapid urease tests(RUTs)-including the newly developed HelicotecUT plus test and HelicotecUT test,and established CLO test and ProntoDry test.H.pylori status was defined as positive when the culture was positive or if there were concordant positive results among histology,CLO test and ProntoDry test.RESULTS:When dual specimens were applied,sensitivity was enhanced and RUT reaction time was signif icantly reduced,regardless of their treatment status.Thirty minutes were enough to achieve an agreeable positive rate in all the RUTs.Both newly developed RUTs showed comparable sensitivity,specif icity and accuracy to the established RUTs,regardless of patient treatment status,RUT reaction duration,and EGD biopsy sites.CONCLUSION:Combination of antrum and body biopsy specimens greatly enhances the sensitivity of rapid urease test and reduces the reaction duration to 30 min.展开更多
Helicobacter pylori(H.pylori)colonizes the stomach of humans and causes chronic infection.The majority of bacteria live in the mucus layer overlying the gastric epithelial cells and only a small proportion of bacteria...Helicobacter pylori(H.pylori)colonizes the stomach of humans and causes chronic infection.The majority of bacteria live in the mucus layer overlying the gastric epithelial cells and only a small proportion of bacteria are found interacting with the epithelial cells.The bacteria living in the gastric mucus may act as a reservoir of infection for the underlying cells which is essential for the development of disease.Colonization of gastric mucus is likely to be key to the establishment of chronic infection.How H.pylori manages to colonise and survive in the hostile environment of the human stomach and avoid removal by mucus flow and killing by gastric acid is the subject of this review.We also discuss how bacterial and host factors may together go some way to explaining the susceptibility to colonization and the outcome of infection in different individuals.H.pylori infection of the gastric mucosa has become a paradigm for chronic infection.Understanding of why H.pylori is such a successful pathogen may help us understand how other bacterial species colonise mucosal surfaces and cause disease.展开更多
AIM: To investigate and compare frequencies of serum positive cagA in patients from two separate regions of Turkey who were grouped according to the presence of peptic ulcer disease or non-ulcer dyspepsia.METHODS: One...AIM: To investigate and compare frequencies of serum positive cagA in patients from two separate regions of Turkey who were grouped according to the presence of peptic ulcer disease or non-ulcer dyspepsia.METHODS: One hundred and eighty Helicobacter pyloripositive patients with peptic ulcer disease or non-ulcer dyspepsia were included in the study. One hundred and fourteen patients had non-ulcer dyspepsia and 66 had peptic ulcer disease (32 with gastric ulcers and/or erosions and 34with duodenal ulcers). Each patient was tested for serum antibody to H. pylori cagA protein by enzyme immunoassay.RESULTS: The total frequency of serum positive cagA in the study group was 97.2 %. The rates in the patients with peptic ulcers and in those with non-ulcer dyspepsia were 100% and 95.6%, respectively. These results were similar to those reported in Asian studies, but higher than those that have been noted in other studies from Turkey and Western countries.CONCLUSION: The high rates of serum positive cagA in these patients with peptic ulcer disease and non-ulcer dyspepsia were similar to results reported in Asia. The fact that there was high seroum prevalence regardless of ulcer status suggests that factors other than cagA might be responsible for ulceration or other types of severe pathology in H. pylori-positive individuals.展开更多
Soil remediation is an important part of the restoration process of degraded terrestrial ecosystems.Due to its unique properties,biochar is being used widely as an effective soil modifier in agricultural systems,but r...Soil remediation is an important part of the restoration process of degraded terrestrial ecosystems.Due to its unique properties,biochar is being used widely as an effective soil modifier in agricultural systems,but research is still rare on biochar application in grassland ecosystems,especially in degraded alpine grasslands.In this study,we conducted a plot experiment to investigate the effect of biochar application on soil physicochemical properties and microorganisms at the 0–20 cm soil depth of a degraded alpine grassland in Qinghai-Tibet Plateau,China.The experiment consisted of four corn straw biochar application levels(0%,0.5%,1%and 2%,with the percentage representing the ratio of biochar weight to the dry weight of soil in the surface 20 cm soil layer).When the biochar addition increased from 0%to 2%,total nitrogen,total organic carbon and available phosphorus in the 0–10 cm soil layer increased by 41%,55%and 45%,respectively,in the second year after biochar addition.Meanwhile,soil electrical conductivity decreased,and soil water content increased.Total microbial,fungal and bacterial biomasses in the 0–10 cm soil layer increased from 9.15 to 12.68,0.91 to 1.34,and 3.85 to 4.55μg g^(-1),respectively.The relative biomasses of saprophytic fungi and methanotrophic bacteria decreased,while the relative biomasses of ectomycorrhizal fungi and arbuscular mycorrhizal fungi increased.These results indicate that biochar has a great potential in improving microbial activity and soil fertility in soil remediation of the degraded alpine grassland.展开更多
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JST SPRING,Grant Number JPMJSP2119Japan Society for the Promotion of Science(JSPS)KAKENHI Grant Number JP22H01581。
文摘Enzyme induced carbonate precipitation(EICP)is a promising technique in the field of biocementation due to its efficiency and controllability.Although many studies have proved its reliability in different environment,little attention has been paid to the influence of humic substances on the EICP.Humic substances cover most of the surface soil across the world land with vegetation,which varies according to the density of vegetation and climate.To understand the compatibility of this technique to distinct problematic soils,it is important to figure out how humic substances could affect the carbonate precipitation process induced by urease enzyme.Therefore,this study aims to investigate the effects of humic acid(HA),one type of humic substance,on the soil solidification through EICP.For this purpose,HA was added to natural soil with varying addition amounts(0%,1%,2%,4%,8%,16%)in soil column solidification tests.The results found that the cementation effectiveness was enhanced by a small amount of HA addition(<4%),while an addition up to 8%greatly inhibited the formation of calcium carbonate.At the same time,soil samples were buffered by HA in a weak acidic condition,thus preventing the emission of undesirable by-product ammonia in the ureolysis process.Therefore,this study makes a contribution to research on enzymatic biocementation by demonstrating the effects of HA on the cementation effectiveness of EICP technique.
文摘[Objective] The aim was to study on effects of "straw returning and ir-returning" and "irrigation with ground water and water in the Yellow River" on changes of enzyme activity in soils under wheat at different developmental stages. [Method] Jimai 22, a kind of winter wheat, was made use of in fields to study on effects of "straw returning and ir-returning" and "irrigation with ground water and water in the Yellow River" on changes of enzyme activity in soils under wheat in different developmental stages. [Result] With advancement of developmental stage, urease activity of wheat in the four groups all showed the trend of "increasing-decreasing-increasing" and activities of invertase and phosphatase both changed from increasing to decreasing. In addition, urease activities of soils in wheat roots were improved by straw returning in four developmental stages. Meanwhile, activity of soil enzyme was better promoted by irrigation with ground water than with water in the Yellow River, except in grain-filling stage. Before developmental stage, different processing methods had a significant effect on phosphatase activity, for example, straw returning and ground water significantly enhanced activities of two kinds of phosphatase and promoted P absorption and transferring by plants and microorganisms in jointing stage; activity of acid phosphatase was higher in the group where irrigation with ground water and straw returning were adopted than those in the rest three groups in booting stage. [Conclusion] The research laid a foundation for dynamic relationship among activity of soil enzyme, crop growth and microorganisms.
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...
基金Supported by Buddhist Dalin Tzu Chi General Hospital
文摘AIM: To investigate the association of colorectal adenomas with both Helicobacter pylori (H. pylori) infection and metabolic syndrome. METHODS: Using a cross-sectional hospital-based study, we analyzed physical examination data from 9311 healthy subjects with overnight physical examinations performed between January 2004 and December 2006. Examined data included gender, age, life style, anthropometric measurements, blood pressure, biochemical and hematological studies, H. pylori infection detected by esophagogastroduodenoscopy and biopsy urease tests, and colorectal adenomas detected with a complete total colonoscopy. RESULTS: The prevalence values for H. pylori infection, metabolic syndrome, and colorectal adenoma were39.2%, 18.7%, and 20.7%, respectively. Colorectal adenoma risk factors included male gender [odd ratio (OR): 2.005, 95% conf idence interval (CI): 1.740-2.310, P < 0.001], advanced age (OR: 1.046, 95% CI: 1.040-1.052, P < 0.001), smoking (OR: 1.377, 95% CI: 1.146-1.654, P = 0.001), increased body fat (OR: 1.016, 95% CI: 1.007-1.026, P = 0.001), higher white blood cell count (OR: 1.038, 95% CI: 1.005-1.073, P = 0.025), H. pylori infection (OR: 1.366, 95% CI: 1.230-1.517, P < 0.001), and metabolic syndrome (OR: 1.408, 95% CI: 1.231-1.610, P < 0.001). In addition, concomitant H. pylori infection with metabolic syndrome further increased the probability of colorectal adenomas. CONCLUSION: Our study revealed H. pylori infection with concomitant metabolic syndrome might further increase the risk of colorectal adenomas.
文摘Over the past several years, the severity of Helicobacter pylori(H. pylori) infections has not significantly diminished. After successful eradication, the annual H. pylori recurrence rate is approximately 13% due tooral H. pylori infection. Established clinical diagnostic techniques do not identify an oral etiologic basis of H. pylori prior to gastric infection. There has been disagreement as to whether oral infection of H. pylori exists or not, with no definite conclusion. In medical practice, negative results with the urea breath test suggest that the stomach infection of H. pylori is cured in these patients. In fact, patients can present negative urea breath test results and yet exhibit H. pylori infection due to oral infection. The present paper provides evidence that H. pylori oral infection is nonetheless present, and the oral cavity represents a secondary site for H. pylori colonization.
基金Project supported by the National Basic Research Program (973) of China (No. 2004CB418506)the National Natural Science Foundation of China (No. 20337010+1 种基金40301022)the Key Laboratory of Environmental Engineering Foundation of Shenyang University (No. 04001).
文摘The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.
文摘The term gastrointestinal stromal tumors （GISTs） is defined diagnostically as the main group of mesenchymal tumors with spindle or epithelioid cells arising from the wall of the gastrointestinal tract with immunohistochemical reactivity for CD117 antibody. Previous studies revealed that cells in GISTs express a growth factor receptor with tyrosine kinase activity （termed c-kit）, which is the product of the c-kit protooncogene. The most specific and practical diagnostic criteria for GISTs are： immunohistochemically determined c-kit （CD117） expression; mitotic score; and tumor size. A small GIST concomitant with early gastric cancer is rarely encountered clinically. Herein we have reported a case of a 1.1-cm GIST detected by esophagogastroduo denoscopy concomitant with a IIc type of early gastric cancer （signet ring cell type）. It was detected during a routine physical health examination. To our knowledge, this is the first report of a small GIST concomitant with a signet ring cell type of early gastric cancer.
文摘Individual and combined effects of Cu, Pb, Zn and Cd on N mineralization, urease and phosphatase were examined in a Typic Udic Ferrisol in laboratory by employing an uniform design and a single factor design.Soil pollution caused by heavy metals inhibited N mineralization (No value) and urease and phosphatase activities. The combined pollution of metals alleviated their toxicity to N mineralization to some extent,whereas aggravated the toxicity to urease and phosphatase. Phosphorous application could mitigate the toxic effect of heavy metals on phosphatase activities, while alleviating effect of N application on the toxicity of heavy metals to urease was inconsistent. However, the mitigating effect of the fertilizers was limited in heavily polluted soils.
基金supported by the National Key Basic Research Program of China (No.2004CB418503)the National Natural Science Foundation of China (No.40801203)
文摘Due to frequent soil Cd contamination and wide use of butachlor in China,there is a need to assess their combined toxicity to soil microorganisms.The combined effects of cadmium(Cd,10 mg kg-1 soil) and herbicide butachlor(10,50,and 100 mg kg-1 soil) on enzyme activities and microbial community structure in a paddy soil were assessed using the traditional enzyme assays and random amplified polymorphic DNA(RAPD) analysis.The results showed that urease and phosphatase activities were significantly reduced by high butachlor concentration(100 mg kg-1 soil).When the concentrations of Cd and butachlor added were at a ratio of 1:10,urease and phosphatase activities were significantly decreased whereas enzyme activities were greatly improved at the ratio of 1:5,which indicated that the combined effects of Cd and butachlor on soil urease and phosphatase activities depended largely on their addition concentration ratios.Random amplified polymorphic DNA(RAPD) analysis showed loss of original bands and appearance of new bands when compared with the control soil.Random amplified polymorphic DNA fingerprints suggested substantial differences between the control and treated soil samples,with apparent changes in the number and size of amplified DNA fragments.The addition of high concentration butachlor and the combined impacts of Cd and butachlor significantly affected the diversity of the microbial community.RAPD analysis in conjunction with other biomarkers such as soil enzyme parameters would prove a powerful ecotoxicological tool.Further investigations should be carried out to understand the clear link between RAPD patterns and enzyme activity.
文摘To increase fertilizer use efficiency （FUE） and to minimize its negative impact on environment have been the focal points in the world for a long time. It is very important to increase FUE in China for its relatively low FUE and serious losses of nutrients. Recent advances of the technologies to increase FUE are reviewed in this article. These include site-specific and real-time nitrogen management, non-destructive quick test of the nitrogen status of plants, new types of slow release and controlled release fertilizers, site-specific nutrient management, and use of urease inhibitor and nitrification inhibitor to decrease nitrogen losses. Future outlook in technologies related to FUE improvement is also discussed.
基金Supported by A Grant from Kaohsiung Medical University Hospital (M094015, 94-KMUH-032, KMUH95-5D51)E-Da Hospital (EDAH-D-97(P)014A)+1 种基金Excellence for cancer research center grant, No DOH99-TD-C-111-002Department of Health, Executive Yuan, Taiwan
文摘AIM:To evaluate the influence of multiple samplings during esophagogastr oduodenoscopy(EGD) on the accuracy of the rapid urease test,and the validity of newly developed rapid urease tests,HelicotecUT plus test and HelicotecUT test,CLO test and ProntoDry test.METHODS:A total of 355 patients undergoing EGD for dyspepsia were included.Their Helicobacter pylori(H.pylori) treatment status was either nave or eradicated.Six biopsy specimens from antrum and gastric body,respectively,were obtained during EGD.Single antral specimens and dual(antrum+body) specimens were compared.Infection status of H.pylori was evaluated by three different tests:culture,histology,and four different commercially available rapid urease tests(RUTs)-including the newly developed HelicotecUT plus test and HelicotecUT test,and established CLO test and ProntoDry test.H.pylori status was defined as positive when the culture was positive or if there were concordant positive results among histology,CLO test and ProntoDry test.RESULTS:When dual specimens were applied,sensitivity was enhanced and RUT reaction time was signif icantly reduced,regardless of their treatment status.Thirty minutes were enough to achieve an agreeable positive rate in all the RUTs.Both newly developed RUTs showed comparable sensitivity,specif icity and accuracy to the established RUTs,regardless of patient treatment status,RUT reaction duration,and EGD biopsy sites.CONCLUSION:Combination of antrum and body biopsy specimens greatly enhances the sensitivity of rapid urease test and reduces the reaction duration to 30 min.
基金Supported by A post graduate student grant awarded by Irish Research Council for Science Engineering and Technology(To Dunne C)an award from the Health Research Board Ireland(To Dolan B)a grant from Science Foundation Ireland,No.08/SRC/B1393
文摘Helicobacter pylori(H.pylori)colonizes the stomach of humans and causes chronic infection.The majority of bacteria live in the mucus layer overlying the gastric epithelial cells and only a small proportion of bacteria are found interacting with the epithelial cells.The bacteria living in the gastric mucus may act as a reservoir of infection for the underlying cells which is essential for the development of disease.Colonization of gastric mucus is likely to be key to the establishment of chronic infection.How H.pylori manages to colonise and survive in the hostile environment of the human stomach and avoid removal by mucus flow and killing by gastric acid is the subject of this review.We also discuss how bacterial and host factors may together go some way to explaining the susceptibility to colonization and the outcome of infection in different individuals.H.pylori infection of the gastric mucosa has become a paradigm for chronic infection.Understanding of why H.pylori is such a successful pathogen may help us understand how other bacterial species colonise mucosal surfaces and cause disease.
文摘AIM: To investigate and compare frequencies of serum positive cagA in patients from two separate regions of Turkey who were grouped according to the presence of peptic ulcer disease or non-ulcer dyspepsia.METHODS: One hundred and eighty Helicobacter pyloripositive patients with peptic ulcer disease or non-ulcer dyspepsia were included in the study. One hundred and fourteen patients had non-ulcer dyspepsia and 66 had peptic ulcer disease (32 with gastric ulcers and/or erosions and 34with duodenal ulcers). Each patient was tested for serum antibody to H. pylori cagA protein by enzyme immunoassay.RESULTS: The total frequency of serum positive cagA in the study group was 97.2 %. The rates in the patients with peptic ulcers and in those with non-ulcer dyspepsia were 100% and 95.6%, respectively. These results were similar to those reported in Asian studies, but higher than those that have been noted in other studies from Turkey and Western countries.CONCLUSION: The high rates of serum positive cagA in these patients with peptic ulcer disease and non-ulcer dyspepsia were similar to results reported in Asia. The fact that there was high seroum prevalence regardless of ulcer status suggests that factors other than cagA might be responsible for ulceration or other types of severe pathology in H. pylori-positive individuals.
基金supported by Beijing Science and Technology Plan,China(No.Z181100009618031)the National Natural Science Foundation of China(No.41771255)+1 种基金the National Key Research and Development Program of China(Nos.2016YFC0501902 and 2018YFF0213405)the Key Science and Technology Project of Qinghai Province,China(No.2018-NK-A2)。
文摘Soil remediation is an important part of the restoration process of degraded terrestrial ecosystems.Due to its unique properties,biochar is being used widely as an effective soil modifier in agricultural systems,but research is still rare on biochar application in grassland ecosystems,especially in degraded alpine grasslands.In this study,we conducted a plot experiment to investigate the effect of biochar application on soil physicochemical properties and microorganisms at the 0–20 cm soil depth of a degraded alpine grassland in Qinghai-Tibet Plateau,China.The experiment consisted of four corn straw biochar application levels(0%,0.5%,1%and 2%,with the percentage representing the ratio of biochar weight to the dry weight of soil in the surface 20 cm soil layer).When the biochar addition increased from 0%to 2%,total nitrogen,total organic carbon and available phosphorus in the 0–10 cm soil layer increased by 41%,55%and 45%,respectively,in the second year after biochar addition.Meanwhile,soil electrical conductivity decreased,and soil water content increased.Total microbial,fungal and bacterial biomasses in the 0–10 cm soil layer increased from 9.15 to 12.68,0.91 to 1.34,and 3.85 to 4.55μg g^(-1),respectively.The relative biomasses of saprophytic fungi and methanotrophic bacteria decreased,while the relative biomasses of ectomycorrhizal fungi and arbuscular mycorrhizal fungi increased.These results indicate that biochar has a great potential in improving microbial activity and soil fertility in soil remediation of the degraded alpine grassland.
