The aim of this study was to evaluate the factors influencing the inactivation effect of intense pulsed light(IPL)on Aeromonas salmonicida grown on chicken meat and skin,and to further develop prediction models of ina...The aim of this study was to evaluate the factors influencing the inactivation effect of intense pulsed light(IPL)on Aeromonas salmonicida grown on chicken meat and skin,and to further develop prediction models of inactivation.In this work,chicken meat and skin inoculated with meat-borne A.salmonicida isolates were subjected to IPL treatments under different conditions.The results showed that IPL had obvious bactericidal effect in the chicken skin and thickness groups when the treatment voltage and time were 7 V combined with 5 s.In addition,the lethality curves of A.salmonicida were fitted under IPL conditions of 3.5-7.5 V.The comparison of statistical parameters revealed that the Weibull model could best fit the mortality curves and could accurately predict the mortality dynamic of A.salmonicida grown on chicken skin.And further a secondary model between the scale factor b and the treatment voltage in Weibull model was established using linear equations,which determined that the secondary model could accurately predict the inactivation of A.salmonicida.This study provides a theoretical basis for future prediction models of Aeromonas,and also provides new ideas for sterilization approaches of meat-borne Aeromonas.展开更多
A coaxial dielectric barrier discharge plasma jet was designed, which can be operated in atmospheric pressure argon under an intermediate frequency sinusoidal resonant power supply, and an atmospheric pressure glow-li...A coaxial dielectric barrier discharge plasma jet was designed, which can be operated in atmospheric pressure argon under an intermediate frequency sinusoidal resonant power supply, and an atmospheric pressure glow-like discharge was achieved. Two kinds of typical bacteria, i.e., the Staphylococcus aureus (S. aureus) and Escherichia coil (E. coil), were employed to study the bacterial inactivation mechanism by means of the non-thermal plasma. The killing log value (KLV) of S. aureus reached up to 5.38 with a treatment time of 90 s and that of E. coil up to 5.36 with 60 s, respectively. According to the argon emission spectra of the plasma jet and the scanning electron microscope (SEM) images of the two bacteria before and after the plasma treatment, it is concluded that the reactive species in the argon plasma played a major role in the bacterial inactivation, while the heat, electric field and UV photons had little effect.展开更多
Response surface methodology (RSM) was employed in the present work and a second orderquadratic equation for high hydrostatic pressure (HHP) inactivation was built. Theadequacy of the model equation for predicting the...Response surface methodology (RSM) was employed in the present work and a second orderquadratic equation for high hydrostatic pressure (HHP) inactivation was built. Theadequacy of the model equation for predicting the optimum response values was verifiedeffectively by the validation data. Effects of temperature, pressure, and pressureholding time on HHP inactivation of Escherichia coli ATCC 8739 were explored. Byanalyzing the response surface plots and their corresponding contour plots as well assolving the quadratic equation, the optimum process parameters for inactivation E. coliof six log cycles were obtained as: temperature 32.2℃, pressure 346.4 MPa, and pressureholding time 12.6min.展开更多
In this paper, the mechanism of yeast inactivation in low temperature atmospheric pressure helium, nitrogen and air plasmas generated by dielectric barrier discharge is analysed and compared. The results show that all...In this paper, the mechanism of yeast inactivation in low temperature atmospheric pressure helium, nitrogen and air plasmas generated by dielectric barrier discharge is analysed and compared. The results show that all the three gas plasmas have a high germicidal efficiency. The morphology of the yeast is observed by scanning electron microscopy, which reveals that the yeast treated in helium plasma is ruptured completely but there are only some flaws on the cell walls in the nitrogen and air plasma treated samples. Also, the flaws on the cell walls treated by air plasma are more significant than that by nitrogen treatment. Simultaneously, the pH values of the samples after 5 rain nitrogen and air plasma treatment have no remarkable change either, while the sample treated with helium plasma descends below 4.0, which is beyond the optimum one for the yeast's living environment. The difference in pH values may be caused by the treatment effect and the degree of the cell's rupture when the gas discharge plasma treatment is applied.展开更多
Objective To better understand the mechanism of chlorine resistance of mycobacteria and evaluate the efficiency of various disinfection processes.Methods Inactivation experiments of one strain Mycobacteria mucogenicum...Objective To better understand the mechanism of chlorine resistance of mycobacteria and evaluate the efficiency of various disinfection processes.Methods Inactivation experiments of one strain Mycobacteria mucogenicum,isolated from a drinking water distribution system in South China were conducted with various chlorine disinfectants.Inactivation efficiency and disinfectant residual,as well as the formation of organic chloramines,were measured during the experiments.Results This strain of M.mucogenicum showed high resistance to chlorine.The CT values of 99.9% inactivation by free chlorine,monochloramine and chlorine dioxide were detected as 29.6±1.46,170±6.16,and 10.9±1.55 min(mg/L) respectively,indicating that chlorine dioxide exhibited significantly higher efficiency than free chlorine and monochloramine.It was also found that M.mucogenicum reacted with chlorine disinfectants more slowly than S.aureus,but consumed more chlorine disinfectants during longer time of contact.Lipid analysis of the cell construction revealed that 95.7% of cell membrane lipid of M.mucogenicum was composed of saturated long chain fatty acids.Saturated fatty acids were regarded as more stable and more hydrophilic which enabled the cell membrane to prevent the diffusion of chlorine.Conclusion It was concluded that different compositions of cell membrane might endow M.mucogenicum with a higher chlorine resistance.展开更多
Pulsed plasma discharge was employed to inactivate bacteria in the injection water for an oil field. The effects of water conductivity and initial concentration of bacteria on elimination efficiency were investigated ...Pulsed plasma discharge was employed to inactivate bacteria in the injection water for an oil field. The effects of water conductivity and initial concentration of bacteria on elimination efficiency were investigated in the batch and continuous flow modes. It was demonstrated that Fe2+ contained in injection water could enhance the elimination efficiency greatly. The addition of reducing agent glutathione (GSH) indicated that active radicals generated by pulsed plasma discharges played an important role in the inactivation of bacteria. Moreover, it was found that the microbial inactivation process for both batch and continuous flow mode well fitted the model based on the Weibull's survival function.展开更多
A closed form of an analytical expression of concentration in the single-enzyme, single-substrate system for the full range of enzyme activities has been derived. The time dependent analytical solution for substrate, ...A closed form of an analytical expression of concentration in the single-enzyme, single-substrate system for the full range of enzyme activities has been derived. The time dependent analytical solution for substrate, enzyme-substrate complex and product concentrations are presented by solving system of non-linear differential equation. We employ He’s Homotopy perturbation method to solve the coupled non-linear differential equations containing a non-linear term related to basic enzymatic reaction. The time dependent simple analytical expressions for substrate, enzyme-substrate and free enzyme concentrations have been derived in terms of dimensionless reaction diffusion parameters ε, λ1, λ2 and λ3 using perturbation method. The numerical solution of the problem is also reported using SCILAB software program. The analytical results are compared with our numerical results. An excellent agreement with simulation data is noted. The obtained results are valid for the whole solution domain.展开更多
Objective To introduce synergetic inactivation of microorganisms in drinking water by short-term free chlorination for less than 15 minutes followed by monochloramination. Methods Indicator microorganisms such as Esch...Objective To introduce synergetic inactivation of microorganisms in drinking water by short-term free chlorination for less than 15 minutes followed by monochloramination. Methods Indicator microorganisms such as Escherichia coli, Staphylococcus aureus, Candida albicans, and spores of Bacillus subtilis were used to assess the efficiency of sequential chlorination and free chlorination. Results The sequential chlorination was more efficient in inactivating these microorganisms than free chlorination, indicating that synergy was provided by free chlorine and monochloramine. Ammonia addition time, temperature and pH had influences on this synergy. Conclusion The possible mechanism of this synergy might involve three aspects: free chlorine causing sublethal injury to microorganisms and monochloramine further inactivating them; different ability of free chlorine and monochloramine to penetrate and inactivate microorganism congeries; and higher concentration of residual chlorine in sequential chlorination than in free chlorination.展开更多
Objective:Angioimmunoblastic T cell lymphoma(AITL)is an aggressive form of non-Hodgkin lymphoma derived from mature T cells.However,the underlying pathogenesis of AITL remains unresolved.We aimed to explore the role o...Objective:Angioimmunoblastic T cell lymphoma(AITL)is an aggressive form of non-Hodgkin lymphoma derived from mature T cells.However,the underlying pathogenesis of AITL remains unresolved.We aimed to explore the role of FOXO1-mediated signaling in the tumorigenesis and progression of AITL.Methods:FOXO1 expression was assessed using immunohistochemistry on a total of 46 AITL tissue samples.Retroviruses encoding FOXO1 shRNA were used to knockdown FOXO1 expression in CD4^+T cells.Flow cytometric assays analyzed the proliferation and survival of FOXO1 knockdown CD4^+T cells.Furthermore,we performed adoptive T-cell transfer experiments to identify whether inactivation of FOXO1 induced neoplastic follicular-helper T(Tfh)cell polarization and function.Results:Patients with low FOXO1 protein levels were prone to have an advanced tumor stage(P=0.049),higher ECOG ps(P=0.024),the presence of bone marrow invasion(P=0.000),and higher IPI(P=0.035).Additionally,the survival rates of patients in the FOXO1 high-expression group were significantly better than those in the FOXO1 low-expression group(χ^2=5.346,P=0.021).We also observed that inactivation of FOXO1 increased CD4^+T cell proliferation and altered the survival and cell-cycle progression of CD4^+T cells.Finally,we confirmed that inactivation of FOXO1 induces Tfh cell programing and function.Conclusions:Inactivation of FOXO1 in AITL plays a key role in the tumorigenesis and progression of AITL.We propose that FOXO1 expression could be a useful prognostic marker in AITL patients to predict poor survival,and to design appropriate therapeutic strategies.展开更多
The multifunctionality and the advantages of thermal plasma for the fast inactivation of viable cells and degradation of organic compounds dissolved in waste water are presented.A complete bacterial inactivation proce...The multifunctionality and the advantages of thermal plasma for the fast inactivation of viable cells and degradation of organic compounds dissolved in waste water are presented.A complete bacterial inactivation process was observed and studied using a thermal plasma treatment source with very short application times,in particular for Staphylococcus aureus bundle spore survival.The survival curves and analyses of the experimental data of the initial and final densities of S.aureus bacteria show a dramatic inhibitory effect of the plasma discharge on the residual bacteria survival ratio.As the exposure time increased,the inactivation process rate increased for direct exposure more than it did for indirect exposure.The evaluation of direct and indirect exposure was based on the analysis of the ultraviolet spectrum from the absorbance spectra of the organic compound dye called benzene sulfonate(C(16)H(11)N2Na O4S)and of viable cells called S.aureus.Organic compounds were degraded and viable cells were killed in a short time by thermal plasma.Moreover,analyses of total carbon,total organic carbon,and total inorganic carbon showed a fast decrease in organically bound carbon,however,this was not as fast as the absorbance spectra revealed by the exposure time increasing more for direct exposure than indirect exposure.After 100 s of exposure to the organic compound dye the removal had a maximun of 40%for samples with indirect exposure to the plasma and a maximum of 90%for samples with the direct exposure.For both samples,where some organic contaminants still remained in treated water,four electrolytes(KCl,Na Cl,Na2SO4,and CH3COONa)were added to be effective for complete sterilization,reaching a purity of 100%.A proposal is made for an optimized thermal plasma water purification system(TPWPS)to improve fast inactivation of microbes and the degradation of organic compounds dissolved in water(especially for direct exposure rather than indirect exposure)using a hybrid plasma torch with an electrical power of 125 kW(500 V–250 A)producing a high-temperature(10 000 K–19 000 K)plasma jet with a maximum gas consumption of 28 mg s^-1.展开更多
The effect of plasma-processed air(PPA)treatment with different conditions(time,power andflow rate)on the inactivation of Escherichia coli(E.coli)in button mushroom was evaluated.Response surface methodology(RSM)was a...The effect of plasma-processed air(PPA)treatment with different conditions(time,power andflow rate)on the inactivation of Escherichia coli(E.coli)in button mushroom was evaluated.Response surface methodology(RSM)was applied to optimize PPA treatments on the E.coli of button mushrooms.According to the response surface analysis,the optimal treatment parameters were a treatment time of 12 min,treatment power of 90 W and flow rate of 1.2 l min-1.As with verifying tests from the optimization exercise,the number of E.coli reduced by 5.27 log CFU/g at the determined optimum conditions.The scanning electronic microscopy(SEM)micrography showed that the surface of the E.coli was significantly changed under the optimized PPA treatment.Quality parameters of button mushrooms treated at the determined optimum conditions were compared with untreated samples during the storage for 12 d at 4°C?±?1°C.The PPA treatment was found to be effective in inhibiting microbes and preserving postharvest quality in button mushrooms,and these results suggested PPA treatment may provide an alternative for the sterilization of foodborne and maintaining postharvest of fruits and vegetables.展开更多
In the last decade,soybean allergies have been on the increases to such an extent that they have now become a public health issue thus prompting more studies and researches on the topic.The allergenicity of soybean is...In the last decade,soybean allergies have been on the increases to such an extent that they have now become a public health issue thus prompting more studies and researches on the topic.The allergenicity of soybean is attributed to its protein fraction.The best way to prevent hypersensitive patients from ingesting allergenic compounds is to exclude such soybean allergens from their diet.As a result,it is essential to provide detailed and reliable knowledge of food ingredients.Therefore,precise and reliable approaches for detecting soybean allergens found in various food products must be used.The main way to reduce allergy risk is the identification of allergenic sites in food and their inactivation by various food-processing methods.It has been reported that food processing may lead to the modification of conformational structure of the protein or protein distortion that inhibit the binding of immunoglobulin E(Ig E)to epitopes on food allergens and also the mechanism of allergic reactions.Food processing technologies employed for inactivating allergenic epitopes used thermal and nonthermal techniques.Currently,several detection methods including protein-based and DNA-based approaches using analytical techniques such as enzyme-linked immunosorbent assay(ELISA),enzyme allergosorbent test(EAST),radioallergosorbent test(RAST),lateral flow immunoassay(LFIA),immunoblotting,realtime polymerase chain reaction(PCR),mass spectrometry and biosensors have been improved for identifying and quantifying these epitopes.This research focused on allergenic proteins of soybean,the most modern approaches for detecting and quantifying these allergens,and finally,the various methods used to inactivate these proteins and their effects on soy allergenicity.展开更多
This paper reviews three complex interactions between microwave energy and microorganisms (bacteria, fungi, and viruses). The first interaction comprises the detection of viruses within human blood using a 50-Ohm tran...This paper reviews three complex interactions between microwave energy and microorganisms (bacteria, fungi, and viruses). The first interaction comprises the detection of viruses within human blood using a 50-Ohm transmission-line vector net-analyzer (typically 0 to 10 dBm @ 2 to 8.5 GHz) where the blood is placed within a test chamber that acts as a non-50-Ohm discontinuity. The second interaction employs 1 to 6.5 W @ 8 to 26 GHz for microwave feed-horn illumination to inactivate microorganisms at an applied power density of 10 to 100 mW<sup>-2</sup>. The third interaction is within multi-mode microwave ovens, where microorganism cell membrane disruption occurs at a few 100 s of W @ 2.45 GHz and microorganism inactivation between 300 to 1800 W @ 2.45 GHz. Within the first microwave interaction, blood relaxation processes are examined. Whereas in the latter two microwave interactions, the following disruption, and inactivation mechanisms are examined: chemical cellular lysis and, microwave resonant absorption causing cell wall rupture, and thermodynamic analysis in terms of process energy budget and suspension energy density. In addition, oven-specific parameters are discussed.展开更多
This paper describes the use of log-linear energy phase-space projections to analyze microwave-assisted inactivation of bacteria and viruses under different fomite conditions within multimode microwave ovens. The oven...This paper describes the use of log-linear energy phase-space projections to analyze microwave-assisted inactivation of bacteria and viruses under different fomite conditions within multimode microwave ovens. The ovens are operated at a cavity-magnetron frequency of 2.45 ± 01 GHz. Porous fomites (moist face towels, cotton swabs, kitchen sponges, and scrubbing pads, cigarette filters and N95-like respirators);along with non-porous hard surface syringe fomites are studied. The fomites are classed as dielectric;and absorb microwave energy to varying degrees depending on their complex dielectric permittivity. Microorganism resilience to microwave stress (defined as ≥4 log<sub>10</sub> reduction in inactivation) when mapped using iso-volume trend-lines in energy phase-space reveals the persistence imparted by the fomite, and can be mapped between different microwave ovens. Microorganism resilience to thermal microwave-assisted treatment increases from vegetative Gram-negative to vegetative Gram-positive and on to Gram-positive spores. Bacteriophage MS2 and influenza viruses have an intermediate resilience dependency. It is shown that linear-scaled fomite temperature against process time graphs can differentiate between non-thermal and thermal micro-wave-assisted treatment of microorganisms.展开更多
We study the target inactivation and recovery in two-layer networks. Five kinds of strategies are chosen to attack the two-layer networks and to recover the activity of the networks by increasing the inter-layer coupl...We study the target inactivation and recovery in two-layer networks. Five kinds of strategies are chosen to attack the two-layer networks and to recover the activity of the networks by increasing the inter-layer coupling strength. The results show that we can easily control the dying state effectively by a randomly attacked situation. We then investigate the recovery activity of the networks by increasing the inter-layer coupled strength. The optimal values of the inter-layer coupled strengths are found, which could provide a more effective range to recovery activity of complex networks. As the multilayer systems composed of active and inactive elements raise important and interesting problems, our results on the target inactivation and recovery in two-layer networks would be extended to different studies.展开更多
UAtomic oxygen radical anion (O-) is one of the most active oxygen species, and has extremely high oxidation ability toward small-molecules of hydrocarbons. However, to our knowledge, little is known about the effec...UAtomic oxygen radical anion (O-) is one of the most active oxygen species, and has extremely high oxidation ability toward small-molecules of hydrocarbons. However, to our knowledge, little is known about the effects of O- on cells of micro-organisms. This work showed that O- could quickly react with the Bacillus subtilis cells and seriously damage the cell walls a s well as their other contents, leading to a fast and irreversible inactivation. SEM micrographs revealed that the cell structures were dramatically destroyed by their exposure to O-. The inactivation efficiencies of B. subtilis depend on the O- intensity, the initial population of cells and the treatment temperature, but not on the pH in the range of our investigation. For a cell concentration of 10^6 cfu/ml, the number of survived cells dropped from 10^6 cfu/ml to 10^3 cfu/ml after about five-minute irradiation by an O- flux in an intensity of 233 nA/cm^2 under a dry argon environment (30 ℃, 1 atm, exposed size: 1.8 cm^2). The inactivation mechanism of micro-organisms induced by O- is also discussed.展开更多
Bacterial resistance is today a matter of great medical concern,so it is urgent to investigate alternatives to alleviate it.Photodynamic inactivation(PDI)is a method that has been endorsed to inactivate diferent patho...Bacterial resistance is today a matter of great medical concern,so it is urgent to investigate alternatives to alleviate it.Photodynamic inactivation(PDI)is a method that has been endorsed to inactivate diferent pathogens,including bacteria,fungi and viruses.PDI is achieved by using a photosensitizer(PS)molecule which generates reactive oxygen species under visible or UV ra-diation.We use visible light and UV-A radiation to excite four commercial PSs(methylene blue,rose bengal,riboflavin and curcumin),and nanopartides synthesized in our laboratory.Despite these PSs having been thoroughly studied in the past by other research groups,in order to compare their effects in an appropriate way,we matched the number of photons they absorb.We found that methylene blue leads to the major inactivation of Escherichia coli.Furthermore,we evaluated the production of singlet axygen and hydroxyl radicals in the photoinactivation process.展开更多
Summary: This study examined the postoperative plasma endotoxin level, plasma endotoxin inactivation capacity and clinical outcome after administration of an enteral diet supplemented with glutamine, arginine and ω-...Summary: This study examined the postoperative plasma endotoxin level, plasma endotoxin inactivation capacity and clinical outcome after administration of an enteral diet supplemented with glutamine, arginine and ω-3-fatty acid in patients undergoing gastrointestinal operations on an prospective, randomized and double-blind design. 40 patients undergoing gastrointestinal operations were randomized into two groups, with each having 20 patients. One group received standard enteral nutrition and the other was fed the formulation supplemented with glutamine, arginine and ω-3-fatty acid. The two groups were isonitrogenous. The infusion was started from day 1 after surgery and continued for 7 days. Blood samples were collected on the morning of day 1 before operation and on the morning of 1, 4 and 7 day(s) after operation and analyzed for plasma endotoxin level and endotoxin inactivation capacity (EIC). Our study found no differences between the two groups on plasma endotoxin level. After surgery a rapid reduction in plasma endotoxin inactivation capacity was observed in both groups, a significant recovery of the plasma endotoxin inactivation capacity was observed on morning of day 4 after surgery in the study group (0. 12±0.02 EU/mL and 0. 078±0. 022 EU/mL respectively. P〈0.01). Shortened hospital stay was observed in the experimental group (11.7±2.0 days in the control group and 10.6±1.2 days in the experimental group respectively, P=0.03). It is concluded that perioperative parenteral nutrition supplemented with glutamine, arginine and ω-3-fatty acid ameliorated postoperative immunodepression but without direct effect on endotoxemia.展开更多
In order to investigate whether an air–water plasma jet is beneficial to improve the efficiency of inactivation, a series of experiments were done using a ring-needle plasma jet. The water content in the working gas...In order to investigate whether an air–water plasma jet is beneficial to improve the efficiency of inactivation, a series of experiments were done using a ring-needle plasma jet. The water content in the working gas(air) was accurately measured based on the Karl Fischer method. The effects of water on the production of OH(A;Σ;–X;Π;) and O(3p;P–3s;S) were also studied by optical emission spectroscopy. The results show that the water content is in the range of 2.53–9.58 mg l;, depending on the gas/water mixture ratio. The production of OH(A;Σ;–X;Π;) rises with the increase of water content, whereas the O(3p;P–3s;S) shows a declining tendency with higher water content. The sterilization experiments indicate that this air–water plasma jet inactivates the P. digitatum spores very effectively and its efficiency rises with the increase of the water content. It is possible that OH(A;Σ;–X;Π;) is a more effective species in inactivation than O(3p;P–3s;S) and the water content benefit the spore germination inhibition through rising the OH(A;Σ;–X;Π;) production. The maximum of the inactivation efficacy is up to 93% when the applied voltage is -6.75 kV and the water content is 9.58 mg l;.展开更多
基金supported by projects funded by grants from the Natural Science Foundation of Jiangsu Province in China(BK20221515)the National Natural Science Foundation of China(32172266)the Changzhou Science and Technology Support Program(CE20222002)。
文摘The aim of this study was to evaluate the factors influencing the inactivation effect of intense pulsed light(IPL)on Aeromonas salmonicida grown on chicken meat and skin,and to further develop prediction models of inactivation.In this work,chicken meat and skin inoculated with meat-borne A.salmonicida isolates were subjected to IPL treatments under different conditions.The results showed that IPL had obvious bactericidal effect in the chicken skin and thickness groups when the treatment voltage and time were 7 V combined with 5 s.In addition,the lethality curves of A.salmonicida were fitted under IPL conditions of 3.5-7.5 V.The comparison of statistical parameters revealed that the Weibull model could best fit the mortality curves and could accurately predict the mortality dynamic of A.salmonicida grown on chicken skin.And further a secondary model between the scale factor b and the treatment voltage in Weibull model was established using linear equations,which determined that the secondary model could accurately predict the inactivation of A.salmonicida.This study provides a theoretical basis for future prediction models of Aeromonas,and also provides new ideas for sterilization approaches of meat-borne Aeromonas.
基金supported in part by China Foundation for the Author of National Excellent Doctoral Dissertation(No.200338)New Century Excellent Talents in University(No.NCET-04-0943)
文摘A coaxial dielectric barrier discharge plasma jet was designed, which can be operated in atmospheric pressure argon under an intermediate frequency sinusoidal resonant power supply, and an atmospheric pressure glow-like discharge was achieved. Two kinds of typical bacteria, i.e., the Staphylococcus aureus (S. aureus) and Escherichia coil (E. coil), were employed to study the bacterial inactivation mechanism by means of the non-thermal plasma. The killing log value (KLV) of S. aureus reached up to 5.38 with a treatment time of 90 s and that of E. coil up to 5.36 with 60 s, respectively. According to the argon emission spectra of the plasma jet and the scanning electron microscope (SEM) images of the two bacteria before and after the plasma treatment, it is concluded that the reactive species in the argon plasma played a major role in the bacterial inactivation, while the heat, electric field and UV photons had little effect.
文摘Response surface methodology (RSM) was employed in the present work and a second orderquadratic equation for high hydrostatic pressure (HHP) inactivation was built. Theadequacy of the model equation for predicting the optimum response values was verifiedeffectively by the validation data. Effects of temperature, pressure, and pressureholding time on HHP inactivation of Escherichia coli ATCC 8739 were explored. Byanalyzing the response surface plots and their corresponding contour plots as well assolving the quadratic equation, the optimum process parameters for inactivation E. coliof six log cycles were obtained as: temperature 32.2℃, pressure 346.4 MPa, and pressureholding time 12.6min.
基金supported by the National Natural Science Foundation of China(Grant No.10275010)
文摘In this paper, the mechanism of yeast inactivation in low temperature atmospheric pressure helium, nitrogen and air plasmas generated by dielectric barrier discharge is analysed and compared. The results show that all the three gas plasmas have a high germicidal efficiency. The morphology of the yeast is observed by scanning electron microscopy, which reveals that the yeast treated in helium plasma is ruptured completely but there are only some flaws on the cell walls in the nitrogen and air plasma treated samples. Also, the flaws on the cell walls treated by air plasma are more significant than that by nitrogen treatment. Simultaneously, the pH values of the samples after 5 rain nitrogen and air plasma treatment have no remarkable change either, while the sample treated with helium plasma descends below 4.0, which is beyond the optimum one for the yeast's living environment. The difference in pH values may be caused by the treatment effect and the degree of the cell's rupture when the gas discharge plasma treatment is applied.
基金funded by the Major Science and Technology Program for Water Pollution Control and Treatment (No. 2008ZX07420‐005)National Natural Science Foundation of China (No. 50708050)
文摘Objective To better understand the mechanism of chlorine resistance of mycobacteria and evaluate the efficiency of various disinfection processes.Methods Inactivation experiments of one strain Mycobacteria mucogenicum,isolated from a drinking water distribution system in South China were conducted with various chlorine disinfectants.Inactivation efficiency and disinfectant residual,as well as the formation of organic chloramines,were measured during the experiments.Results This strain of M.mucogenicum showed high resistance to chlorine.The CT values of 99.9% inactivation by free chlorine,monochloramine and chlorine dioxide were detected as 29.6±1.46,170±6.16,and 10.9±1.55 min(mg/L) respectively,indicating that chlorine dioxide exhibited significantly higher efficiency than free chlorine and monochloramine.It was also found that M.mucogenicum reacted with chlorine disinfectants more slowly than S.aureus,but consumed more chlorine disinfectants during longer time of contact.Lipid analysis of the cell construction revealed that 95.7% of cell membrane lipid of M.mucogenicum was composed of saturated long chain fatty acids.Saturated fatty acids were regarded as more stable and more hydrophilic which enabled the cell membrane to prevent the diffusion of chlorine.Conclusion It was concluded that different compositions of cell membrane might endow M.mucogenicum with a higher chlorine resistance.
基金supported by Zhejiang Province Welfare Technology Applied Research Project of China(No.2014C31137)National Natural Science Foundation of China(Nos.21436007 and U1462201)the Fundamental Research Funds for the Central Universities of China(No.2015QNA4032)
文摘Pulsed plasma discharge was employed to inactivate bacteria in the injection water for an oil field. The effects of water conductivity and initial concentration of bacteria on elimination efficiency were investigated in the batch and continuous flow modes. It was demonstrated that Fe2+ contained in injection water could enhance the elimination efficiency greatly. The addition of reducing agent glutathione (GSH) indicated that active radicals generated by pulsed plasma discharges played an important role in the inactivation of bacteria. Moreover, it was found that the microbial inactivation process for both batch and continuous flow mode well fitted the model based on the Weibull's survival function.
文摘A closed form of an analytical expression of concentration in the single-enzyme, single-substrate system for the full range of enzyme activities has been derived. The time dependent analytical solution for substrate, enzyme-substrate complex and product concentrations are presented by solving system of non-linear differential equation. We employ He’s Homotopy perturbation method to solve the coupled non-linear differential equations containing a non-linear term related to basic enzymatic reaction. The time dependent simple analytical expressions for substrate, enzyme-substrate and free enzyme concentrations have been derived in terms of dimensionless reaction diffusion parameters ε, λ1, λ2 and λ3 using perturbation method. The numerical solution of the problem is also reported using SCILAB software program. The analytical results are compared with our numerical results. An excellent agreement with simulation data is noted. The obtained results are valid for the whole solution domain.
基金This work was part of a project (No. 50708050)supported by the National Natural Science Foundation of China.
文摘Objective To introduce synergetic inactivation of microorganisms in drinking water by short-term free chlorination for less than 15 minutes followed by monochloramination. Methods Indicator microorganisms such as Escherichia coli, Staphylococcus aureus, Candida albicans, and spores of Bacillus subtilis were used to assess the efficiency of sequential chlorination and free chlorination. Results The sequential chlorination was more efficient in inactivating these microorganisms than free chlorination, indicating that synergy was provided by free chlorine and monochloramine. Ammonia addition time, temperature and pH had influences on this synergy. Conclusion The possible mechanism of this synergy might involve three aspects: free chlorine causing sublethal injury to microorganisms and monochloramine further inactivating them; different ability of free chlorine and monochloramine to penetrate and inactivate microorganism congeries; and higher concentration of residual chlorine in sequential chlorination than in free chlorination.
基金supported by Natural Science Foundation of Fujian Province (Grant No. 2015J01314)
文摘Objective:Angioimmunoblastic T cell lymphoma(AITL)is an aggressive form of non-Hodgkin lymphoma derived from mature T cells.However,the underlying pathogenesis of AITL remains unresolved.We aimed to explore the role of FOXO1-mediated signaling in the tumorigenesis and progression of AITL.Methods:FOXO1 expression was assessed using immunohistochemistry on a total of 46 AITL tissue samples.Retroviruses encoding FOXO1 shRNA were used to knockdown FOXO1 expression in CD4^+T cells.Flow cytometric assays analyzed the proliferation and survival of FOXO1 knockdown CD4^+T cells.Furthermore,we performed adoptive T-cell transfer experiments to identify whether inactivation of FOXO1 induced neoplastic follicular-helper T(Tfh)cell polarization and function.Results:Patients with low FOXO1 protein levels were prone to have an advanced tumor stage(P=0.049),higher ECOG ps(P=0.024),the presence of bone marrow invasion(P=0.000),and higher IPI(P=0.035).Additionally,the survival rates of patients in the FOXO1 high-expression group were significantly better than those in the FOXO1 low-expression group(χ^2=5.346,P=0.021).We also observed that inactivation of FOXO1 increased CD4^+T cell proliferation and altered the survival and cell-cycle progression of CD4^+T cells.Finally,we confirmed that inactivation of FOXO1 induces Tfh cell programing and function.Conclusions:Inactivation of FOXO1 in AITL plays a key role in the tumorigenesis and progression of AITL.We propose that FOXO1 expression could be a useful prognostic marker in AITL patients to predict poor survival,and to design appropriate therapeutic strategies.
基金financial support from MEPhI in the framework of the Russian Academic Excellence Project
文摘The multifunctionality and the advantages of thermal plasma for the fast inactivation of viable cells and degradation of organic compounds dissolved in waste water are presented.A complete bacterial inactivation process was observed and studied using a thermal plasma treatment source with very short application times,in particular for Staphylococcus aureus bundle spore survival.The survival curves and analyses of the experimental data of the initial and final densities of S.aureus bacteria show a dramatic inhibitory effect of the plasma discharge on the residual bacteria survival ratio.As the exposure time increased,the inactivation process rate increased for direct exposure more than it did for indirect exposure.The evaluation of direct and indirect exposure was based on the analysis of the ultraviolet spectrum from the absorbance spectra of the organic compound dye called benzene sulfonate(C(16)H(11)N2Na O4S)and of viable cells called S.aureus.Organic compounds were degraded and viable cells were killed in a short time by thermal plasma.Moreover,analyses of total carbon,total organic carbon,and total inorganic carbon showed a fast decrease in organically bound carbon,however,this was not as fast as the absorbance spectra revealed by the exposure time increasing more for direct exposure than indirect exposure.After 100 s of exposure to the organic compound dye the removal had a maximun of 40%for samples with indirect exposure to the plasma and a maximum of 90%for samples with the direct exposure.For both samples,where some organic contaminants still remained in treated water,four electrolytes(KCl,Na Cl,Na2SO4,and CH3COONa)were added to be effective for complete sterilization,reaching a purity of 100%.A proposal is made for an optimized thermal plasma water purification system(TPWPS)to improve fast inactivation of microbes and the degradation of organic compounds dissolved in water(especially for direct exposure rather than indirect exposure)using a hybrid plasma torch with an electrical power of 125 kW(500 V–250 A)producing a high-temperature(10 000 K–19 000 K)plasma jet with a maximum gas consumption of 28 mg s^-1.
基金supported by National Natural Science Foundation of China(No.31972144)supported by Beijing University of Agriculture(BAU)。
文摘The effect of plasma-processed air(PPA)treatment with different conditions(time,power andflow rate)on the inactivation of Escherichia coli(E.coli)in button mushroom was evaluated.Response surface methodology(RSM)was applied to optimize PPA treatments on the E.coli of button mushrooms.According to the response surface analysis,the optimal treatment parameters were a treatment time of 12 min,treatment power of 90 W and flow rate of 1.2 l min-1.As with verifying tests from the optimization exercise,the number of E.coli reduced by 5.27 log CFU/g at the determined optimum conditions.The scanning electronic microscopy(SEM)micrography showed that the surface of the E.coli was significantly changed under the optimized PPA treatment.Quality parameters of button mushrooms treated at the determined optimum conditions were compared with untreated samples during the storage for 12 d at 4°C?±?1°C.The PPA treatment was found to be effective in inhibiting microbes and preserving postharvest quality in button mushrooms,and these results suggested PPA treatment may provide an alternative for the sterilization of foodborne and maintaining postharvest of fruits and vegetables.
基金supported by the Natural Science Foundation of China(NSFC,32172310)Youth Key Teachers from Henan University of Technology(21420043)the Innovative Funds Plan of Henan University of Technology(2020ZKCJ19)。
文摘In the last decade,soybean allergies have been on the increases to such an extent that they have now become a public health issue thus prompting more studies and researches on the topic.The allergenicity of soybean is attributed to its protein fraction.The best way to prevent hypersensitive patients from ingesting allergenic compounds is to exclude such soybean allergens from their diet.As a result,it is essential to provide detailed and reliable knowledge of food ingredients.Therefore,precise and reliable approaches for detecting soybean allergens found in various food products must be used.The main way to reduce allergy risk is the identification of allergenic sites in food and their inactivation by various food-processing methods.It has been reported that food processing may lead to the modification of conformational structure of the protein or protein distortion that inhibit the binding of immunoglobulin E(Ig E)to epitopes on food allergens and also the mechanism of allergic reactions.Food processing technologies employed for inactivating allergenic epitopes used thermal and nonthermal techniques.Currently,several detection methods including protein-based and DNA-based approaches using analytical techniques such as enzyme-linked immunosorbent assay(ELISA),enzyme allergosorbent test(EAST),radioallergosorbent test(RAST),lateral flow immunoassay(LFIA),immunoblotting,realtime polymerase chain reaction(PCR),mass spectrometry and biosensors have been improved for identifying and quantifying these epitopes.This research focused on allergenic proteins of soybean,the most modern approaches for detecting and quantifying these allergens,and finally,the various methods used to inactivate these proteins and their effects on soy allergenicity.
文摘This paper reviews three complex interactions between microwave energy and microorganisms (bacteria, fungi, and viruses). The first interaction comprises the detection of viruses within human blood using a 50-Ohm transmission-line vector net-analyzer (typically 0 to 10 dBm @ 2 to 8.5 GHz) where the blood is placed within a test chamber that acts as a non-50-Ohm discontinuity. The second interaction employs 1 to 6.5 W @ 8 to 26 GHz for microwave feed-horn illumination to inactivate microorganisms at an applied power density of 10 to 100 mW<sup>-2</sup>. The third interaction is within multi-mode microwave ovens, where microorganism cell membrane disruption occurs at a few 100 s of W @ 2.45 GHz and microorganism inactivation between 300 to 1800 W @ 2.45 GHz. Within the first microwave interaction, blood relaxation processes are examined. Whereas in the latter two microwave interactions, the following disruption, and inactivation mechanisms are examined: chemical cellular lysis and, microwave resonant absorption causing cell wall rupture, and thermodynamic analysis in terms of process energy budget and suspension energy density. In addition, oven-specific parameters are discussed.
文摘This paper describes the use of log-linear energy phase-space projections to analyze microwave-assisted inactivation of bacteria and viruses under different fomite conditions within multimode microwave ovens. The ovens are operated at a cavity-magnetron frequency of 2.45 ± 01 GHz. Porous fomites (moist face towels, cotton swabs, kitchen sponges, and scrubbing pads, cigarette filters and N95-like respirators);along with non-porous hard surface syringe fomites are studied. The fomites are classed as dielectric;and absorb microwave energy to varying degrees depending on their complex dielectric permittivity. Microorganism resilience to microwave stress (defined as ≥4 log<sub>10</sub> reduction in inactivation) when mapped using iso-volume trend-lines in energy phase-space reveals the persistence imparted by the fomite, and can be mapped between different microwave ovens. Microorganism resilience to thermal microwave-assisted treatment increases from vegetative Gram-negative to vegetative Gram-positive and on to Gram-positive spores. Bacteriophage MS2 and influenza viruses have an intermediate resilience dependency. It is shown that linear-scaled fomite temperature against process time graphs can differentiate between non-thermal and thermal micro-wave-assisted treatment of microorganisms.
基金Supported by the National Basic Research Program of China under Grant Nos 2013CBA01502,2011CB921503 and 2013CB834100the National Natural Science Foundation of China under Grant Nos 11374040 and 11274051
文摘We study the target inactivation and recovery in two-layer networks. Five kinds of strategies are chosen to attack the two-layer networks and to recover the activity of the networks by increasing the inter-layer coupling strength. The results show that we can easily control the dying state effectively by a randomly attacked situation. We then investigate the recovery activity of the networks by increasing the inter-layer coupled strength. The optimal values of the inter-layer coupled strengths are found, which could provide a more effective range to recovery activity of complex networks. As the multilayer systems composed of active and inactive elements raise important and interesting problems, our results on the target inactivation and recovery in two-layer networks would be extended to different studies.
基金the innovation program 2002 by CAS in China,(No.KJ0364)
文摘UAtomic oxygen radical anion (O-) is one of the most active oxygen species, and has extremely high oxidation ability toward small-molecules of hydrocarbons. However, to our knowledge, little is known about the effects of O- on cells of micro-organisms. This work showed that O- could quickly react with the Bacillus subtilis cells and seriously damage the cell walls a s well as their other contents, leading to a fast and irreversible inactivation. SEM micrographs revealed that the cell structures were dramatically destroyed by their exposure to O-. The inactivation efficiencies of B. subtilis depend on the O- intensity, the initial population of cells and the treatment temperature, but not on the pH in the range of our investigation. For a cell concentration of 10^6 cfu/ml, the number of survived cells dropped from 10^6 cfu/ml to 10^3 cfu/ml after about five-minute irradiation by an O- flux in an intensity of 233 nA/cm^2 under a dry argon environment (30 ℃, 1 atm, exposed size: 1.8 cm^2). The inactivation mechanism of micro-organisms induced by O- is also discussed.
基金supported by CONACyT,Mexico under Grant A1-S-8125 and Fideicomiso SEPCINVESTAV(FIDSC2018/72).
文摘Bacterial resistance is today a matter of great medical concern,so it is urgent to investigate alternatives to alleviate it.Photodynamic inactivation(PDI)is a method that has been endorsed to inactivate diferent pathogens,including bacteria,fungi and viruses.PDI is achieved by using a photosensitizer(PS)molecule which generates reactive oxygen species under visible or UV ra-diation.We use visible light and UV-A radiation to excite four commercial PSs(methylene blue,rose bengal,riboflavin and curcumin),and nanopartides synthesized in our laboratory.Despite these PSs having been thoroughly studied in the past by other research groups,in order to compare their effects in an appropriate way,we matched the number of photons they absorb.We found that methylene blue leads to the major inactivation of Escherichia coli.Furthermore,we evaluated the production of singlet axygen and hydroxyl radicals in the photoinactivation process.
文摘Summary: This study examined the postoperative plasma endotoxin level, plasma endotoxin inactivation capacity and clinical outcome after administration of an enteral diet supplemented with glutamine, arginine and ω-3-fatty acid in patients undergoing gastrointestinal operations on an prospective, randomized and double-blind design. 40 patients undergoing gastrointestinal operations were randomized into two groups, with each having 20 patients. One group received standard enteral nutrition and the other was fed the formulation supplemented with glutamine, arginine and ω-3-fatty acid. The two groups were isonitrogenous. The infusion was started from day 1 after surgery and continued for 7 days. Blood samples were collected on the morning of day 1 before operation and on the morning of 1, 4 and 7 day(s) after operation and analyzed for plasma endotoxin level and endotoxin inactivation capacity (EIC). Our study found no differences between the two groups on plasma endotoxin level. After surgery a rapid reduction in plasma endotoxin inactivation capacity was observed in both groups, a significant recovery of the plasma endotoxin inactivation capacity was observed on morning of day 4 after surgery in the study group (0. 12±0.02 EU/mL and 0. 078±0. 022 EU/mL respectively. P〈0.01). Shortened hospital stay was observed in the experimental group (11.7±2.0 days in the control group and 10.6±1.2 days in the experimental group respectively, P=0.03). It is concluded that perioperative parenteral nutrition supplemented with glutamine, arginine and ω-3-fatty acid ameliorated postoperative immunodepression but without direct effect on endotoxemia.
基金supported by National Natural Science Foundation of China (NSFC) under Grants No. 51407020National Key Technology Research and Development Program of the Ministry of Science and Technology of China under Grants No. 2014BAC13B05Visiting Scholarship of State Key Laboratory of Power Transmission Equipment & System Security and New Technology (Chongqing University) No. 2007DA10512716404
文摘In order to investigate whether an air–water plasma jet is beneficial to improve the efficiency of inactivation, a series of experiments were done using a ring-needle plasma jet. The water content in the working gas(air) was accurately measured based on the Karl Fischer method. The effects of water on the production of OH(A;Σ;–X;Π;) and O(3p;P–3s;S) were also studied by optical emission spectroscopy. The results show that the water content is in the range of 2.53–9.58 mg l;, depending on the gas/water mixture ratio. The production of OH(A;Σ;–X;Π;) rises with the increase of water content, whereas the O(3p;P–3s;S) shows a declining tendency with higher water content. The sterilization experiments indicate that this air–water plasma jet inactivates the P. digitatum spores very effectively and its efficiency rises with the increase of the water content. It is possible that OH(A;Σ;–X;Π;) is a more effective species in inactivation than O(3p;P–3s;S) and the water content benefit the spore germination inhibition through rising the OH(A;Σ;–X;Π;) production. The maximum of the inactivation efficacy is up to 93% when the applied voltage is -6.75 kV and the water content is 9.58 mg l;.