Antibiotics residues have been accumulating in the environment day by day due to overuse of antibiotics.Recalcitrant antibiotic residues,such as tylosin(TYL),can cause serious environmental problems,which makes it imp...Antibiotics residues have been accumulating in the environment day by day due to overuse of antibiotics.Recalcitrant antibiotic residues,such as tylosin(TYL),can cause serious environmental problems,which makes it important to eliminate TYL from the environment.It is important to eliminate TYL from the environment.In this study,a strain was isolated and purified from fermentation by-product that came from a TYL production factory.The TYL degrading strain was identified by its morphology,physiological and biochemical reactions and sequencing the PCR-amplified fragments of its 16 S r DNAcoding genes.The temperature,shaking speed,initial TYL concentration,p H and inoculum sizes were investigated under simulated conditions by using single factor tests.The results showed that TYL2,a high efficient strain was isolated and was identified as Brevibacillus borstelensis.The degradation rate of TYL by this strain could reach to 75%with an initial concentration of 25 mg L^-1 within 7 days under conditions of 7%B.borstelensis(v/v,2×108 CFU m L^-1)at p H 7.0 and at 35°C.It is interesting that this strain has a very strong ability to degrade the TYL in natural sewage with the degradation rate of 65%within 7 days.This result could be helpful for the degradation of TYL and provide guidance for the degradation of other antibiotics.展开更多
The screening effect of the random-phase-approximation on the states of shallow donor impurities in free strained wurtzite GaN/AlxGa1-xN heterojunctions under hydrostatic pressure and an external electric field is inv...The screening effect of the random-phase-approximation on the states of shallow donor impurities in free strained wurtzite GaN/AlxGa1-xN heterojunctions under hydrostatic pressure and an external electric field is investigated by using a variational method and a simplified coherent potential approximation. The variations of Stark energy shift with electric field, impurity position, A1 component and areal electron density are discussed. Our results show that the screening dramatically reduces both the blue and red shifts as well as the binding energies of impurity states. For a given impurity position, the change in binding energy is more sensitive to the increase in hydrostatic pressure in the presence of the screening effect than that in the absence of the screening effect. The weakening of the blue and red shifts, induced by the screening effect, strengthens gradually with the increase of electric field. Furthermore, the screening effect weakens the mixture crystal effect, thereby influencing the Stark effect. The screening effect strengthens the influence of energy band bending on binding energy due to the areal electron density.展开更多
Rare earth barium copper oxide(REBCO)is the most researched and commercialized second-generation high-temperature superconducting material.Due to the anisotropic structure,strong deformation sensitivity,and central fi...Rare earth barium copper oxide(REBCO)is the most researched and commercialized second-generation high-temperature superconducting material.Due to the anisotropic structure,strong deformation sensitivity,and central field errors caused by screening current effects,it is still a challenge for commercialization applications.In this study,the transversely isotropic constitutive relationship is selected as the mechanical model based on the structural characteristics of REBCO tapes,and suitable microelements are selected to equate the elastic constants using their average stress-strain relationships.Then,a two-dimensional axisymmetric model for coils wound by single-layer tapes is constructed to analyze the dependence of the electric-magnetic-force distribution in the tape on the strain.Finally,the anisotropic approximation of the homogenized bulk method is used to equate large-turn high-field coils,and the electric-magnetic-force distribution characteristics of the coils with/without screening effects and mechanical strain conditions are investigated,respectively.The results reveal that the mechanical strain has a weakening effect on the electromagnetic field distribution of superconducting tapes,but causes a significant enhancement in the force field distribution.In the presence of 0.5% mechanical strain,the maximum weakening of the peak value of the current density and the critical current density inside the high-field coil can reach about 8% and 13%,respectively,with a nearly 5 times increase in the peak stress.The screening current makes the current field distribution inside the coil improve by about 10 times.The screening current induced magnetic field can reach up to 0.8 T,making the relative error of the high-field coil center up to 7.8%.展开更多
In this paper, eleven strains, which were screened strictly from raw royal jelly, soil andhoneycomb etc. by meansof dilution plate and spread plate methods, were cultured at 28℃ for 60 h with shaking. To determine wh...In this paper, eleven strains, which were screened strictly from raw royal jelly, soil andhoneycomb etc. by meansof dilution plate and spread plate methods, were cultured at 28℃ for 60 h with shaking. To determine whether they could yield10-Hydroxy-2-decenoic acid during fermentation, gas chromatography and gas chromatography-mass spectrometry methodswere used. The results showed that the strains BH002 and BH004, were both identified as Crytococcaceae, where BH002was primarily classified into Candida for possessing the abilities. The 10-HDA productivity of Candida BH002 and that ofBH004 were 0.327% and 0.2648% respectively.展开更多
Strains from the cellulose-containing environment were collected. Primary screening(by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium) and reelection(by filter-paper...Strains from the cellulose-containing environment were collected. Primary screening(by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium) and reelection(by filter-paper inorganic salt culture medium and sodium carboxymethylcellulose Congo red culture medium) indicated that five strains obtained were best suited for high performance cellulose degradation. Determination of sodium carboxymethylcellulose activity(CMCA) and filter paper activity(FPA) was accomplished for each of the five. The strongest of the five in CMCA and FPA was applied to the production of cellulose bioethanol by separate hydrolysis and fermentation(SHF) and simultaneous saccharification and fermentation(SSF) respectively.展开更多
[Objective] The aim was to screen strains producing alkaline protease from soil and study the conditions for enzyme production.[Method] Eight strains producing alkaline protease were isolated from soil through plate i...[Objective] The aim was to screen strains producing alkaline protease from soil and study the conditions for enzyme production.[Method] Eight strains producing alkaline protease were isolated from soil through plate isolation,and the ability of enzyme production was measured by filter paper and Folin-phenol method.The strain with the strongest ability of enzyme production was screened as a candidate strain,then the factors influencing the ability of enzyme production was studied,finally the conditions for enzyme production was optimized through orthogonal test.[Result] No.5 strain was screened as a candidate strain due to its strong ability of enzyme production(6.00 U/ml),which accounted for 134.1% of that of Bacillus licheniformis,and it was gram-positive bacterium belonging to Clostridium.Orthogonal test showed that the optimal condition for producing protease was an environment with pH=11,0.3% of sucrose and 0.8% of peptone in the fermentation medium,and inoculation amount was 105 cfu/ml.In addition,peptone had significant impact on the level of enzyme production.[Conclusion] The study could provide theoretical references for the screening of strains producing alkaline protease.展开更多
Strain sensors for human-motion detection must offer high stretchability, high sensitivity, fast response, and high recovery speed. In this study, we choose silver paste as a sensing material and use a screen printing...Strain sensors for human-motion detection must offer high stretchability, high sensitivity, fast response, and high recovery speed. In this study, we choose silver paste as a sensing material and use a screen printing method to fabricate the strain sensor based upon an electrical-resistance mechanism. After curing elastomeric polyurethane film with a thickness of 150 μm on PET film, the polyester resin mixed with blocked isocyanate curing agent was coated as a masking layer to reduce the film’s stickiness. The effect of the polyester masking layer upon the silver paste screen printing process was examined using a rolling-ball-tack test, TGA analysis of polyester resins, and cured silver-electrode films. The cost-effective strain sensor fabricated by using silver paste and screen printing processes on the stretchable-polyurethane-substrate film showed high sensitivity and fast response in a strain range of up to 100%.展开更多
[Objectives] This study was conducted to isolate and screen the bacteria that can convert trans-anethole to anisic acid from star anise and its environmental samples, and identify the bacteria. [Methods] According to ...[Objectives] This study was conducted to isolate and screen the bacteria that can convert trans-anethole to anisic acid from star anise and its environmental samples, and identify the bacteria. [Methods] According to the traditional microbial culture method, with trans-anethole as the sole carbon source, through enrichment culture and separation and purification, preliminary screening by thin layer chromatography and re-screening by high-performance liquid chromatography, strains that degraded trans-anethole to produce anisic acid were obtained, and 16 S rDNA sequencing and phylogenetic tree construction were performed for genetic analysis. [Results] Eleven strains that degraded trans-anethole to produce anisic acid were obtained, among which strain NT2 that produced anisic acid with a relatively high efficiency was initially identified as Pseudomonas sp. The strain’s trans-anethole degradation rate was 45.41%, and the molar production rate and cumulative concentration of anisic acid were 21.80% and 1.96 g/L, respectively. [Conclusions] Strain NT2 has a strong ability to degrade trans-anethole to produce anisic acid, and can enrich strain resources for degradation of trans-anethole to anisic acid through microbial conversion.展开更多
[Objective] To isolate and preserve a high-activity Douchi fibrinolytic enzyme producing strain from Douchi products.[Method] The Douchi fibrinolytic enzyme producing strain was screened on the selected medium prepare...[Objective] To isolate and preserve a high-activity Douchi fibrinolytic enzyme producing strain from Douchi products.[Method] The Douchi fibrinolytic enzyme producing strain was screened on the selected medium prepared with self-made pork blood powder,the strain with the highest activity was screened out according to the size of hydrolysis cycle,and then preserved in LB medium.[Result] A Douchi fibrinolytic enzyme producing strain with high thrombolytic activity was successfully screened out from the Douchi produced in Hunan,Guangdong and Jiangxi Provinces.[Conclusion] The study lays foundation for the development of new-type thrombolytic drugs.展开更多
AIM:To identity the factors influencing colorectal cancer(CRC) screening behavior and willingness among Chinese outpatients.METHODS:An outpatient-based face-to-face survey was conducted from August 18 to September 7,2...AIM:To identity the factors influencing colorectal cancer(CRC) screening behavior and willingness among Chinese outpatients.METHODS:An outpatient-based face-to-face survey was conducted from August 18 to September 7,2010 in Changhai Hospital.A total of 1200 consecutive patients aged ≥ 18 years were recruited for interview.The patient's knowledge about CRC and screening was pre-measured as a predictor variable,and other predictors included age,gender,educational level,monthly household income and health insurance status.The relationship between these predictors and screening behavior,screening willingness and screening approach were examined using Pearson's χ2 test and logistic regression analyses.RESULTS:Of these outpatients,22.5% had undergone CRC screening prior to this study.Patients who had participated in the screening were more likely to have good knowledge about CRC and screening(OR:5.299,95% CI:3.415-8.223),have health insurance(OR:1.996,95% CI:1.426-2.794) and older in age.Higher income,however,was found to be a barrier to the screening(OR:0.633,95% CI:0.467-0.858).An analysis of screening willingness showed that 37.5% of the patients would voluntarily participated in a screen at the recommended age,but 41.3% would do so under doctor's advice.Screening willingness was positively correlated with the patient's knowledge status.Patients with higher knowledge levels would like to participate in the screening(OR:4.352,95% CI:3.008-6.298),and they would select colonoscopy as a screening approach(OR:3.513,95% CI:2.290-5.389).However,higher income level was,again,a barrier to colonoscopic screening(OR:0.667,95% CI:0.505-0.908).CONCLUSION:Patient's level of knowledge and income should be taken into consideration when conducting a feasible CRC screening.展开更多
AIM:To explore the DNA image cytometry (DNA-ICM) technique as a primary screening method for esopha-geal squamous precancerous lesions.METHODS:This study was designed as a population-based screening study.A total of 5...AIM:To explore the DNA image cytometry (DNA-ICM) technique as a primary screening method for esopha-geal squamous precancerous lesions.METHODS:This study was designed as a population-based screening study.A total of 582 local residents aged 40 years-69 years were recruited from Linzhou in Henan and Feicheng in Shandong.However,only 452 subjects had results of liquid-based cytology,DNA-ICM and pathology.The sensitivity and specificity of DNA-ICM were calculated and compared with liquid-based cytology in moderate dysplasia or worse.RESULTS:Sensitivities of DNA-ICM ranging from at least 1 to 4 aneuploid cells were 90.91%,86.36%,79.55% and 77.27%,respectively,which were better than that of liquid-based cytology (75%).Specifici-ties of DNA-ICM were 70.83%,84.07%,92.65% and 96.81%,but the specificity of liquid-based cytology was 91.91%.The sensitivity and specificity of a combination of liquid-based cytology and DNA-ICM were 84.09% and 85.78%,respectively.CONCLUSION:It is possible to use DNA-ICM tech-nique as a primary screening method for esophageal squamous precancerous lesions.展开更多
A total of 25 strains were isolated from the intestinal tract of Mystus macropterus. The inhibitory effects of extracellular enzyme activity to common aquat- ic pathogenic bacteria were screened. A probiotic DQHY -7 s...A total of 25 strains were isolated from the intestinal tract of Mystus macropterus. The inhibitory effects of extracellular enzyme activity to common aquat- ic pathogenic bacteria were screened. A probiotic DQHY -7 strain was isolated, and its safety was detected. DQHY -7 strain was preliminarily identified by mor- phological observation, and physiological and biochemical test. Research results showed that DQHY -7 strain had relatively strong production capacities of amylase, cellulase and protease, and could restrict the growth of Escherichia coli, Aeromonas hydrophila and Pseudomonas fluorescens. Results of acute toxicity test showed that 1. 0 × 108 CFU/mL DQHY -7 bacterial suspension showed no pathogenicity to M. macropterus. According to the colony growth pattern and physiological-bio- chemical characteristics of DQHY -7, the strain was identified to be Bacillus subtilis. Research results showed that DQHY -7 strain could be used as a new candi- date strain for feeding microecologicalagent.展开更多
[Objective] The research aimed to screen out an efficient aniline-degrading strain and study its degradation characteristics. [Method] By domesticated enrichment culture, an efficient aniline-degrading strain named as...[Objective] The research aimed to screen out an efficient aniline-degrading strain and study its degradation characteristics. [Method] By domesticated enrichment culture, an efficient aniline-degrading strain named as DA-K was isolated from activated sludge sample collected from a chemical plant in Henan. DA-K could use aniline as the sole carbon and nitrogen sources. The strain was carried out physiological and biochemi- cal identification, and its biological degradation characteristics were studied. [ Result] DA-K strain was G - and red-shaped, and its colony color was off-white. It was initially determined as Acinetobacter sp. By measuring, the optimum growth temperature and pH for DA-K were respectively 30 ~C and 6.0. DA-K strain could grow well in inorganic salt medium with aniline of 2 500 mg/L. After shaking for 96 h under the conditions of pH 6.0, 30 ℃, 180 r/min and 1 000 mg/L of aniline, the degradation rate of the aniline by DA-K could reach nearly 80%. [ Conclusion] The DA-K strain had a higher aniline degradation efficiency and actual treatment capability of the aniline wastewater, which laid foundation for establishing gene engineerincl strain.展开更多
Excessive fusel alcohol contents will cause the beer to produce off-flavors and cause dizziness and headaches.Reducing the contents of fusel alcohols in beer is very important to people's health.The excessive fuse...Excessive fusel alcohol contents will cause the beer to produce off-flavors and cause dizziness and headaches.Reducing the contents of fusel alcohols in beer is very important to people's health.The excessive fusel alcohol contents in beer is a common problem in the industry.How to control the contents of fusel alcohols in a reasonable range is of great significance for improving beer quality.After one round of ultraviolet(UV)and one round of multifunctional plasma mutagenesis system(MPMS)mutagenesis,the yeast strains with lower fusel oil yield and more stablility could be screened.According to the relationship between the fusel alcohol Harris metabolic pathway of brewer's yeast and lactic acid metabolism,excellent strains were obtained by triple screening with lactic acid medium,calcium carbonate medium and 2,3,5-triphenyl tetrazolium chloride upper medium.The content of fusel alcohol in the finished beer fermentation test of screened strain Z43 was 52.1±0.142 mg•L^(-1),which was 43%lower than that of the starting strain,and other fermentation properties remained unchanged.After eight passages,it was verified that the strain was stable and heritable.These results showed that strain Z43 presented promising characteristics for use in the production of beer with a potentially low contents of fusel alcohols.展开更多
AIM: To investigate whether smoking is associated with human papilloma virus(HPV) infection. METHODS: HPV infection is considered to be a neces-sary condition for cervical cancer development. The study population incl...AIM: To investigate whether smoking is associated with human papilloma virus(HPV) infection. METHODS: HPV infection is considered to be a neces-sary condition for cervical cancer development. The study population included 1291 women, aged 25-55 years, attending cervical cancer screening. All women had a Papanicolaou(Pap) test, with liquid-based cytology(Thinprep), an HPV-DNA test and an evaluation of smoking habits. The COBAS 4800 system was used for HPV-DNA testing, enabling identifi cation of the following high-risk HPV(hr HPV)-types: each of HPVs 16 and 18 separately, and HPVs 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68 as a cocktail. The evaluation of smoking habits was assessed using the smoking intensity index(SII), a variable formed as the product of cigarettes consumed per day by the days(years × 365) that a woman was a smoker, divided by 1000. RESULTS: There were 136 smokers among 238 women tested positive for hr HPV-types(HPVs 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and/or 68), and 463 smokers among 1053 hr HPV-negative women(OR = 1.7, P < 0.001). This association was attributed to the youngest age group of women, aged 25-34 years(OR = 2.3, P < 0.001), while there was no association in other age groups. The intensity of smoking(increasing SII) showed no statistically signifi cant association with hr HPV infection. Cervical infection with HPV 16 and/or HPV 18 was also not associated with age or smoking habits. Finally, no association was found between Pap test status and smoking habits or smoking intensity. CONCLUSION: Smoking appears to be associated with hr HPV infection of the uterine cervix, particularly in younger women. Further studies should investigate whether this association is based on causality and evaluate the role of other possible co-factors.展开更多
基金jointly supported by the National Key R&D Program of China(2018YFD0500206)the National Natural Science Foundation of China(31772395)the Fundamental Research Funds for Central Non-profit Scientific Institution,Chinese Academy of Agricultural Sciences(1610132019046)。
文摘Antibiotics residues have been accumulating in the environment day by day due to overuse of antibiotics.Recalcitrant antibiotic residues,such as tylosin(TYL),can cause serious environmental problems,which makes it important to eliminate TYL from the environment.It is important to eliminate TYL from the environment.In this study,a strain was isolated and purified from fermentation by-product that came from a TYL production factory.The TYL degrading strain was identified by its morphology,physiological and biochemical reactions and sequencing the PCR-amplified fragments of its 16 S r DNAcoding genes.The temperature,shaking speed,initial TYL concentration,p H and inoculum sizes were investigated under simulated conditions by using single factor tests.The results showed that TYL2,a high efficient strain was isolated and was identified as Brevibacillus borstelensis.The degradation rate of TYL by this strain could reach to 75%with an initial concentration of 25 mg L^-1 within 7 days under conditions of 7%B.borstelensis(v/v,2×108 CFU m L^-1)at p H 7.0 and at 35°C.It is interesting that this strain has a very strong ability to degrade the TYL in natural sewage with the degradation rate of 65%within 7 days.This result could be helpful for the degradation of TYL and provide guidance for the degradation of other antibiotics.
基金Project supported by the National Natural Science Foundation of China (Grant No 60566002)the Specialized Research Fundfor the Doctoral Program of Higher Education of China (Grant No 20070126001)
文摘The screening effect of the random-phase-approximation on the states of shallow donor impurities in free strained wurtzite GaN/AlxGa1-xN heterojunctions under hydrostatic pressure and an external electric field is investigated by using a variational method and a simplified coherent potential approximation. The variations of Stark energy shift with electric field, impurity position, A1 component and areal electron density are discussed. Our results show that the screening dramatically reduces both the blue and red shifts as well as the binding energies of impurity states. For a given impurity position, the change in binding energy is more sensitive to the increase in hydrostatic pressure in the presence of the screening effect than that in the absence of the screening effect. The weakening of the blue and red shifts, induced by the screening effect, strengthens gradually with the increase of electric field. Furthermore, the screening effect weakens the mixture crystal effect, thereby influencing the Stark effect. The screening effect strengthens the influence of energy band bending on binding energy due to the areal electron density.
文摘Rare earth barium copper oxide(REBCO)is the most researched and commercialized second-generation high-temperature superconducting material.Due to the anisotropic structure,strong deformation sensitivity,and central field errors caused by screening current effects,it is still a challenge for commercialization applications.In this study,the transversely isotropic constitutive relationship is selected as the mechanical model based on the structural characteristics of REBCO tapes,and suitable microelements are selected to equate the elastic constants using their average stress-strain relationships.Then,a two-dimensional axisymmetric model for coils wound by single-layer tapes is constructed to analyze the dependence of the electric-magnetic-force distribution in the tape on the strain.Finally,the anisotropic approximation of the homogenized bulk method is used to equate large-turn high-field coils,and the electric-magnetic-force distribution characteristics of the coils with/without screening effects and mechanical strain conditions are investigated,respectively.The results reveal that the mechanical strain has a weakening effect on the electromagnetic field distribution of superconducting tapes,but causes a significant enhancement in the force field distribution.In the presence of 0.5% mechanical strain,the maximum weakening of the peak value of the current density and the critical current density inside the high-field coil can reach about 8% and 13%,respectively,with a nearly 5 times increase in the peak stress.The screening current makes the current field distribution inside the coil improve by about 10 times.The screening current induced magnetic field can reach up to 0.8 T,making the relative error of the high-field coil center up to 7.8%.
文摘In this paper, eleven strains, which were screened strictly from raw royal jelly, soil andhoneycomb etc. by meansof dilution plate and spread plate methods, were cultured at 28℃ for 60 h with shaking. To determine whether they could yield10-Hydroxy-2-decenoic acid during fermentation, gas chromatography and gas chromatography-mass spectrometry methodswere used. The results showed that the strains BH002 and BH004, were both identified as Crytococcaceae, where BH002was primarily classified into Candida for possessing the abilities. The 10-HDA productivity of Candida BH002 and that ofBH004 were 0.327% and 0.2648% respectively.
基金supported by the Agriculture Application Investigation and I mprovement Item of New Countryside Construction and Promotion Project of the Bureau of Science and Technology in Xi an(No.NC08005)
文摘Strains from the cellulose-containing environment were collected. Primary screening(by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium) and reelection(by filter-paper inorganic salt culture medium and sodium carboxymethylcellulose Congo red culture medium) indicated that five strains obtained were best suited for high performance cellulose degradation. Determination of sodium carboxymethylcellulose activity(CMCA) and filter paper activity(FPA) was accomplished for each of the five. The strongest of the five in CMCA and FPA was applied to the production of cellulose bioethanol by separate hydrolysis and fermentation(SHF) and simultaneous saccharification and fermentation(SSF) respectively.
基金Supported by National Natural Science Foundation of China(31070361)Beijing Outstanding Teaching Team Project about Ecology in 2008+2 种基金The Fundamental Research Funds for the Central Universities (0910KYZY43)Undergraduate Research and Training Project of Minzu University of China (URTP201011115)Quality Course Project of Minzu University of China in 2011
文摘[Objective] The aim was to screen strains producing alkaline protease from soil and study the conditions for enzyme production.[Method] Eight strains producing alkaline protease were isolated from soil through plate isolation,and the ability of enzyme production was measured by filter paper and Folin-phenol method.The strain with the strongest ability of enzyme production was screened as a candidate strain,then the factors influencing the ability of enzyme production was studied,finally the conditions for enzyme production was optimized through orthogonal test.[Result] No.5 strain was screened as a candidate strain due to its strong ability of enzyme production(6.00 U/ml),which accounted for 134.1% of that of Bacillus licheniformis,and it was gram-positive bacterium belonging to Clostridium.Orthogonal test showed that the optimal condition for producing protease was an environment with pH=11,0.3% of sucrose and 0.8% of peptone in the fermentation medium,and inoculation amount was 105 cfu/ml.In addition,peptone had significant impact on the level of enzyme production.[Conclusion] The study could provide theoretical references for the screening of strains producing alkaline protease.
文摘Strain sensors for human-motion detection must offer high stretchability, high sensitivity, fast response, and high recovery speed. In this study, we choose silver paste as a sensing material and use a screen printing method to fabricate the strain sensor based upon an electrical-resistance mechanism. After curing elastomeric polyurethane film with a thickness of 150 μm on PET film, the polyester resin mixed with blocked isocyanate curing agent was coated as a masking layer to reduce the film’s stickiness. The effect of the polyester masking layer upon the silver paste screen printing process was examined using a rolling-ball-tack test, TGA analysis of polyester resins, and cured silver-electrode films. The cost-effective strain sensor fabricated by using silver paste and screen printing processes on the stretchable-polyurethane-substrate film showed high sensitivity and fast response in a strain range of up to 100%.
基金Supported by The Basic Ability Improvement Project for Young and Middle-aged Teachers in Guangxi Universities(2017KY0288)。
文摘[Objectives] This study was conducted to isolate and screen the bacteria that can convert trans-anethole to anisic acid from star anise and its environmental samples, and identify the bacteria. [Methods] According to the traditional microbial culture method, with trans-anethole as the sole carbon source, through enrichment culture and separation and purification, preliminary screening by thin layer chromatography and re-screening by high-performance liquid chromatography, strains that degraded trans-anethole to produce anisic acid were obtained, and 16 S rDNA sequencing and phylogenetic tree construction were performed for genetic analysis. [Results] Eleven strains that degraded trans-anethole to produce anisic acid were obtained, among which strain NT2 that produced anisic acid with a relatively high efficiency was initially identified as Pseudomonas sp. The strain’s trans-anethole degradation rate was 45.41%, and the molar production rate and cumulative concentration of anisic acid were 21.80% and 1.96 g/L, respectively. [Conclusions] Strain NT2 has a strong ability to degrade trans-anethole to produce anisic acid, and can enrich strain resources for degradation of trans-anethole to anisic acid through microbial conversion.
文摘[Objective] To isolate and preserve a high-activity Douchi fibrinolytic enzyme producing strain from Douchi products.[Method] The Douchi fibrinolytic enzyme producing strain was screened on the selected medium prepared with self-made pork blood powder,the strain with the highest activity was screened out according to the size of hydrolysis cycle,and then preserved in LB medium.[Result] A Douchi fibrinolytic enzyme producing strain with high thrombolytic activity was successfully screened out from the Douchi produced in Hunan,Guangdong and Jiangxi Provinces.[Conclusion] The study lays foundation for the development of new-type thrombolytic drugs.
文摘AIM:To identity the factors influencing colorectal cancer(CRC) screening behavior and willingness among Chinese outpatients.METHODS:An outpatient-based face-to-face survey was conducted from August 18 to September 7,2010 in Changhai Hospital.A total of 1200 consecutive patients aged ≥ 18 years were recruited for interview.The patient's knowledge about CRC and screening was pre-measured as a predictor variable,and other predictors included age,gender,educational level,monthly household income and health insurance status.The relationship between these predictors and screening behavior,screening willingness and screening approach were examined using Pearson's χ2 test and logistic regression analyses.RESULTS:Of these outpatients,22.5% had undergone CRC screening prior to this study.Patients who had participated in the screening were more likely to have good knowledge about CRC and screening(OR:5.299,95% CI:3.415-8.223),have health insurance(OR:1.996,95% CI:1.426-2.794) and older in age.Higher income,however,was found to be a barrier to the screening(OR:0.633,95% CI:0.467-0.858).An analysis of screening willingness showed that 37.5% of the patients would voluntarily participated in a screen at the recommended age,but 41.3% would do so under doctor's advice.Screening willingness was positively correlated with the patient's knowledge status.Patients with higher knowledge levels would like to participate in the screening(OR:4.352,95% CI:3.008-6.298),and they would select colonoscopy as a screening approach(OR:3.513,95% CI:2.290-5.389).However,higher income level was,again,a barrier to colonoscopic screening(OR:0.667,95% CI:0.505-0.908).CONCLUSION:Patient's level of knowledge and income should be taken into consideration when conducting a feasible CRC screening.
基金Supported by Grants from the Ministry of Health of China,No.200902002-8Grants from Cancer Institute/Hospital Chinese Academy of Medical Sciences and Peking Union Medical College,No.2009YF50
文摘AIM:To explore the DNA image cytometry (DNA-ICM) technique as a primary screening method for esopha-geal squamous precancerous lesions.METHODS:This study was designed as a population-based screening study.A total of 582 local residents aged 40 years-69 years were recruited from Linzhou in Henan and Feicheng in Shandong.However,only 452 subjects had results of liquid-based cytology,DNA-ICM and pathology.The sensitivity and specificity of DNA-ICM were calculated and compared with liquid-based cytology in moderate dysplasia or worse.RESULTS:Sensitivities of DNA-ICM ranging from at least 1 to 4 aneuploid cells were 90.91%,86.36%,79.55% and 77.27%,respectively,which were better than that of liquid-based cytology (75%).Specifici-ties of DNA-ICM were 70.83%,84.07%,92.65% and 96.81%,but the specificity of liquid-based cytology was 91.91%.The sensitivity and specificity of a combination of liquid-based cytology and DNA-ICM were 84.09% and 85.78%,respectively.CONCLUSION:It is possible to use DNA-ICM tech-nique as a primary screening method for esophageal squamous precancerous lesions.
基金Supported by the Planning Project of Basic Scientific Research Funds of Chongqing(2012-esfc-jbky-00405)
文摘A total of 25 strains were isolated from the intestinal tract of Mystus macropterus. The inhibitory effects of extracellular enzyme activity to common aquat- ic pathogenic bacteria were screened. A probiotic DQHY -7 strain was isolated, and its safety was detected. DQHY -7 strain was preliminarily identified by mor- phological observation, and physiological and biochemical test. Research results showed that DQHY -7 strain had relatively strong production capacities of amylase, cellulase and protease, and could restrict the growth of Escherichia coli, Aeromonas hydrophila and Pseudomonas fluorescens. Results of acute toxicity test showed that 1. 0 × 108 CFU/mL DQHY -7 bacterial suspension showed no pathogenicity to M. macropterus. According to the colony growth pattern and physiological-bio- chemical characteristics of DQHY -7, the strain was identified to be Bacillus subtilis. Research results showed that DQHY -7 strain could be used as a new candi- date strain for feeding microecologicalagent.
基金Supported by National Transgene Special Project, China(2008ZX2008005-001)Major Public Project in Henan Province,China (091100910500)
文摘[Objective] The research aimed to screen out an efficient aniline-degrading strain and study its degradation characteristics. [Method] By domesticated enrichment culture, an efficient aniline-degrading strain named as DA-K was isolated from activated sludge sample collected from a chemical plant in Henan. DA-K could use aniline as the sole carbon and nitrogen sources. The strain was carried out physiological and biochemi- cal identification, and its biological degradation characteristics were studied. [ Result] DA-K strain was G - and red-shaped, and its colony color was off-white. It was initially determined as Acinetobacter sp. By measuring, the optimum growth temperature and pH for DA-K were respectively 30 ~C and 6.0. DA-K strain could grow well in inorganic salt medium with aniline of 2 500 mg/L. After shaking for 96 h under the conditions of pH 6.0, 30 ℃, 180 r/min and 1 000 mg/L of aniline, the degradation rate of the aniline by DA-K could reach nearly 80%. [ Conclusion] The DA-K strain had a higher aniline degradation efficiency and actual treatment capability of the aniline wastewater, which laid foundation for establishing gene engineerincl strain.
基金Supported by Heilongjiang Natural Science Foundation Joint Guide Project(LH2019C022)。
文摘Excessive fusel alcohol contents will cause the beer to produce off-flavors and cause dizziness and headaches.Reducing the contents of fusel alcohols in beer is very important to people's health.The excessive fusel alcohol contents in beer is a common problem in the industry.How to control the contents of fusel alcohols in a reasonable range is of great significance for improving beer quality.After one round of ultraviolet(UV)and one round of multifunctional plasma mutagenesis system(MPMS)mutagenesis,the yeast strains with lower fusel oil yield and more stablility could be screened.According to the relationship between the fusel alcohol Harris metabolic pathway of brewer's yeast and lactic acid metabolism,excellent strains were obtained by triple screening with lactic acid medium,calcium carbonate medium and 2,3,5-triphenyl tetrazolium chloride upper medium.The content of fusel alcohol in the finished beer fermentation test of screened strain Z43 was 52.1±0.142 mg•L^(-1),which was 43%lower than that of the starting strain,and other fermentation properties remained unchanged.After eight passages,it was verified that the strain was stable and heritable.These results showed that strain Z43 presented promising characteristics for use in the production of beer with a potentially low contents of fusel alcohols.
文摘AIM: To investigate whether smoking is associated with human papilloma virus(HPV) infection. METHODS: HPV infection is considered to be a neces-sary condition for cervical cancer development. The study population included 1291 women, aged 25-55 years, attending cervical cancer screening. All women had a Papanicolaou(Pap) test, with liquid-based cytology(Thinprep), an HPV-DNA test and an evaluation of smoking habits. The COBAS 4800 system was used for HPV-DNA testing, enabling identifi cation of the following high-risk HPV(hr HPV)-types: each of HPVs 16 and 18 separately, and HPVs 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68 as a cocktail. The evaluation of smoking habits was assessed using the smoking intensity index(SII), a variable formed as the product of cigarettes consumed per day by the days(years × 365) that a woman was a smoker, divided by 1000. RESULTS: There were 136 smokers among 238 women tested positive for hr HPV-types(HPVs 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and/or 68), and 463 smokers among 1053 hr HPV-negative women(OR = 1.7, P < 0.001). This association was attributed to the youngest age group of women, aged 25-34 years(OR = 2.3, P < 0.001), while there was no association in other age groups. The intensity of smoking(increasing SII) showed no statistically signifi cant association with hr HPV infection. Cervical infection with HPV 16 and/or HPV 18 was also not associated with age or smoking habits. Finally, no association was found between Pap test status and smoking habits or smoking intensity. CONCLUSION: Smoking appears to be associated with hr HPV infection of the uterine cervix, particularly in younger women. Further studies should investigate whether this association is based on causality and evaluate the role of other possible co-factors.