Cultivation of aerobic granules for simultaneous nitrification and denitrification in two sequencing batch airlift bioreactors was studied. Conventional activated floc and anaerobic granules served as main two inocula...Cultivation of aerobic granules for simultaneous nitrification and denitrification in two sequencing batch airlift bioreactors was studied. Conventional activated floc and anaerobic granules served as main two inoculated sludge in the systems. Morphological variations of sludge in the reactors were observed. It was found that the cultivation of aerobic granules was closely associated with the kind of inoculated sludge. Round and regular aerobic granules were prevailed in both reactors, and the physical characteristics of the aerobic granules in terms of settling ability, specific gravity, and ratio of water containing were distinct when the inoculate sludge was different. Aerobic granules formed by seeding activated floc are more excellent in simultaneous nitrification and denitrification than that by aerobic granules formed from anaerobic granules. It was concluded that inoculated sludge plays a crucial role in the cultivation of aerobic granules for simultaneous nitrification and denitrification.展开更多
Objective To understand the infectious characteristics of a hamster-adapted scrapie strain 263K with five different routes of infection including intracerebral (i.e.), intraperitoneal (i.p.), intragastrical (i.g.), in...Objective To understand the infectious characteristics of a hamster-adapted scrapie strain 263K with five different routes of infection including intracerebral (i.e.), intraperitoneal (i.p.), intragastrical (i.g.), intracardiac and intramuscular (i.m.) approaches. Methods Hamsters were infected with crude- or fine-prepared brain extracts. The neuropathological changes, PrPSc deposits, and patterns of PK-resistant PrP were analyzed by HE stain, immunohistochemistry (IHC) assay and Western blot. Reactive gliosis and neuron loss were evaluated by glial fibrillary acidic protein (GFAP) and neuron specific enolase (NSE) specific IHC. Results The animals inoculated in i.m. and Lp. ways with crude PrPSc extracts showed clinical signs at the average incubation of 69.212.8 and 65.5±3.9 days. Inoculation in i.c. and intracardiac ways with fine PrPSc extracts (0.00035 g) caused similar, but relative long incubation of around 90 days. Only one out of eight hamsters challenged in i.g way with low dosage (0.01 g) became ill after a much longer incubation (185 d), while all animals (4/4) with high dosage (0.04 g) developed clinical signs 105 days postinfection. The most remarkable spongiform degeneration and PrPSc deposits were found in brain stem among the five challenge groups generally. The number of GFAP-positive astrocytes increased distinctly in brain stems in all infection groups, while the number of NSE-positive cells decreased significantly in cerebrum, except i.c. group. The patterns of PK-resistant PrP in brains were basically identical among the five infection routes. Conclusion Typical TSE could be induced in hamsters by inoculating strain 263K in the five infection ways. The incubation periods in bioassays depend on infective dosage, administrating pathway and preparation of PrPSc. The neuropathological changes and PrPSc deposits seem to be related with regions and inoculating pathways.展开更多
As a potent nucleating substrate forα-Mg grain,MgAl_(2)O_(4) powder was used to inoculate the Mg-Al melt in this study.The effects of MgAl_(2)O_(4)amount,holding time and Al content on the grain size and grain refini...As a potent nucleating substrate forα-Mg grain,MgAl_(2)O_(4) powder was used to inoculate the Mg-Al melt in this study.The effects of MgAl_(2)O_(4)amount,holding time and Al content on the grain size and grain refining ratio of the inoculated Mg-Al alloys are systematically investigated.The results show that the minimum grain size of Mg-3Al alloy is achieved by adding 2wt.%MgAl_(2)O_(4)powder and this alloy exhibits higher grain refining ratio than Mg-5Al and Mg-8Al alloys.The crystallographic misfit calculation indicates the wellmatching and possible orientation relationships(ORs)betweenα-Mg and MgAl_(2)O_(4).Among these predicted ORs,[10–10]α−Mg//[110]MgAl2O4 in(0002)α−Mg//(1–13)MgAl2O4 possesses the smallest misfit,i.e.,2.34%(fr).Both results of the experiment and crystallographic calculation demonstrate that the grain refinement of Mg-Al alloys is attributed to the MgAl_(2)O_(4)particles acting as the heterogeneous nucleation substrates forα-Mg grains.展开更多
The effect of addition of 0.05wt.% to 0.25 wt.% Ca,Zr,Al-FeSi alloy on in-ladle and in-mould inoculation of grey cast irons was investigated.In the present paper,the conclusions drawn are based on thermal analysis.For...The effect of addition of 0.05wt.% to 0.25 wt.% Ca,Zr,Al-FeSi alloy on in-ladle and in-mould inoculation of grey cast irons was investigated.In the present paper,the conclusions drawn are based on thermal analysis.For the solidification pattern,some specific cooling curves characteristics,such as the degree of undercooling at the beginning of eutectic solidif ication and at the end of solidifi cation,as well as the recalescence level,are identif ied to be more influenced by the inoculation technique.The degree of eutectic undercooling of the electrically melted base iron having 0.025% S,0.003% Al and 3.5% Ce is excessively high(39-40℃),generating a relatively high need for inoculation.Under these conditions,the in-mould inoculation has a more signif icant effect compared to ladle inoculation,especially at lower inoculant usage(less than 0.20 wt.%).Generally,the eff iciency of 0.05wt.% -0.15wt.% of alloy for in-mould inoculation is comparable to,or better than,that of 0.15wt.% -0.25wt.% addition in ladle inoculation procedures.In order to secure stable and controlled processes,representative thermal analysis parameters could be used,especially in thin wall grey iron castings production.展开更多
The characteristics of some elements in inoculant were analyzed.The effect of the morphology of instantaneous inoculant on its melting velocity was studied.When the inoculants pass through the same sieve number,the vo...The characteristics of some elements in inoculant were analyzed.The effect of the morphology of instantaneous inoculant on its melting velocity was studied.When the inoculants pass through the same sieve number,the volume and the ratio of surface area to volume are different.It is evident from the theoretical analysis and experiment under some conditions that the melting velocity of inoculant depends on the morphology of inoculant.The morphology of inoculant during production should be controlled carefully.展开更多
This experiment aimed to evaluate the ruminal degradability in situ of the dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) of Guinea grass silages. The experimental de...This experiment aimed to evaluate the ruminal degradability in situ of the dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) of Guinea grass silages. The experimental design was completely randomized with six treatments and six repetitions: Guinea grass silage, Guinea grass silage inoculated with 10% wheat bran, Guinea grass silage inoculated with 106 cfu/g of strains of Streptococcus bovis JB1;Guinea grass silage inoculated with 106 cfu/g of strains of Streptococcus bovis JB1 plus 10% of wheat bran;Guinea grass silage inoculated with 106 cfu/g of strains of Streptococcus bovis HC5;Guinea grass silage inoculated with 106 cfu/g of strains of Streptococcus bovis HC5 plus 10% of wheat bran. The silages inoculated with Streptococcus bovis and with added wheat bran resulted in higher values of ruminal degradability of DM, 32.76% and 32.17%, and of crude protein 38.28% and 37.89%. For the effective and potential degradability of DM, CP, NDF and ADF the highest values occurred for silages in these silages as well, in all passage rates. There is a similarity between the responses of Streptococcus bovis JB1 and the HC5, and the wheat bran enhanced the effectiveness of the microbial additive.展开更多
Carbide precipitates in Thin Wall Ductile Iron (TWDI) used for automotive applications needs to be eliminated or reduced for improved strength, ductility, crack propagation resistance and good machinability. Ductile i...Carbide precipitates in Thin Wall Ductile Iron (TWDI) used for automotive applications needs to be eliminated or reduced for improved strength, ductility, crack propagation resistance and good machinability. Ductile iron thin section profiles (≤3 mm) present danger of massive carbide precipitations in the as-cast sample. Precipitated carbide phase is brittle and negatively affects the mechanical properties of the iron matrix. The suppression of carbide formation is associated with the nucleating properties of the nodularizer and innoculant alloys. This treatment is vital in ensuring that carbide precipitation, flake graphite structure and non-nodular graphite phases are reduced or completely eliminated in the TWDI castings. Therefore, the temperature and technique of treatment would influence the yield of the process, and ultimately the mechanical properties. In this study, the effect of nodularization and inoculation treatment temperature on the microstructure and mechanical properties of TWDI castings is examined. The results indicate that good nodularity and nodule count with better percent elongations are achieved using low treatment temperatures in descending order of 1490°C, 1470°C and 1450°C, but have negative effect at lower treatment temperature of 1430°C. However, TWDI castings have superior properties in terms of nodule counts and nodularity at 1450°C. Treatment temperature does not produce significant influence on ultimate tensile strength (UTS) and hardness of TWDI castings. TWDI castings show poor nodularity, nodule count and ductility at higher inoculation treatment temperatures of 1550°C, 1530°C and 1510°C.展开更多
<strong>Objectives:</strong> The digestive track of mice and humans has always been an integral part of the pathogenesis of the Trypanosomes but is constantly overlooked. This realization opens up complete...<strong>Objectives:</strong> The digestive track of mice and humans has always been an integral part of the pathogenesis of the Trypanosomes but is constantly overlooked. This realization opens up completely new strategies for the development of trypanosomes vaccines, allowing approaches that parenteral delivery forms would not permit. The target of the study was to compare the haematological changes and immunological responses of trypanosomiasis model systems (mice and rats) inoculated orally and intraperitoneally and to observe the afterward effect of a controlled drug [Isometamidium chloride (ISM)] in the restoration of these initial parameters. <strong>Methods:</strong> To achieve this, a total of 40 rodents (20 rats and 20 mice) were purchased, then grouped into two [sixteen younger (1 - 5 weeks) and older (7 - 15 weeks) groups each]. They were further sub-grouped into five each. Body weights, Parasitaemia and Packed Cell Volume (PCV) were taken before, after inoculation and after treatment with ISM at 4 mg/kg. <strong>Results:</strong> Based on presumptive clinical diagnosis, all rodents inoculated intraperitoneally showed clinical signs of fluctuations in weight, PCV and parasitaemia levels before, after inoculations and after treatment compared to those inoculated orally with a significant difference (P < 0.05) observed. Both young and older rodents also responded differently to the inoculants and to the different methods of inoculation. But more deaths were recorded among the mice when compared to the rats. <strong>Conclusion: </strong>Although these non-transgenic models would not have offered a completely new methods to vaccine development, their differences in response to various methods of inoculations is an indication of an exciting research processes and could offer desired results, particularly where transgenic rodents are employed.展开更多
Ralstonia solanacearum causes a lethal bacterial wilt disease in many crops,leading to huge losses in crop production every year.Understanding of plant-R.solanacearum interactions will aid to develop efficient strateg...Ralstonia solanacearum causes a lethal bacterial wilt disease in many crops,leading to huge losses in crop production every year.Understanding of plant-R.solanacearum interactions will aid to develop efficient strategies to control the disease.As a soilborne pathogen,R.solanacearum naturally infects plants via roots.A huge limitation in studying plant-R.solanacearum interactions is the large variation of R.solanacearum infection assay due to the variable soil conditions and uneven inoculum exposure.Here,we developed a robust and reliable Petri-dish inoculation method which allows consistent and stable infection in young plant seedlings.This method is easy to use,takes about only 10 days from seed germination to the completion of inoculation assay,and requires less inoculum of bacteria as well as growth chamber space.We proved the efficacy of the seedling Petri-dish inoculation method by analyzing plant defense primed by molecular patterns,resistance of defense-related plant mutants,and virulence of R.solanacearum mutants.Furthermore,we demonstrated that the seedling Petri-dish inoculation method can be applied to other host plants such as tobacco and has great potential for high-throughput screening of resistant plant germplasms to bacterial wilt in the future.展开更多
The hypereutectic region of grey cast iron has received very little attention especially for designing cast products by researchers. Due to its high carbon equivalence, hypereutectic grey iron poses some challenges es...The hypereutectic region of grey cast iron has received very little attention especially for designing cast products by researchers. Due to its high carbon equivalence, hypereutectic grey iron poses some challenges especially its tendency for grey to white transition (GWT) at this level of carbon content. However, hypereutectic grey iron possesses inherent properties that could be easily utilized for improved performance in automobile engines and brake pad system. Significantly, they could be modified for superior hardness, strength and toughness. This study presents the effect of microalloying on the mechanical behaviour of hypereutectic grey cast iron with carbon equivalence above 4.5. The first part of this work presented in this paper considers the addition of Cu-Ni and Cu-Ni-Mn to series of as-cast hypereutectic grey cast iron and their hardness and tensile strength were studied and compared. A total of 33 cast samples were obtained with the control sample. The examination of the micrographs revealed that graphite eutectics cells of Type A and A + D were obtained in the resulting microstructure. Results analyses showed that the ferrite forming tendency of silicon was suppressed due to the high carbon content of the as-cast hypereutectic grey iron coupled with the absence of inoculation which plays a great role in the graphite flake type, network, size and distribution. Cu-Ni microalloying was also confirmed to promote hardness with the hardening effect limit of nickel observed at 1.3% composition. For Cu-Mi-Mn addition, excess and free sulphur in the hyper- eutectic grey iron results in reverse effect of manganese on strength, hardness, reduced graphite flake size and shape.展开更多
Bauhinia faberi via.Microphylla(BFM)is an important tree species for vegetation restoration in the dry valley of southwestern China.However,there were few studies on the application of arbuscular mycorrhizal fungi(AMF...Bauhinia faberi via.Microphylla(BFM)is an important tree species for vegetation restoration in the dry valley of southwestern China.However,there were few studies on the application of arbuscular mycorrhizal fungi(AMF)in improving the drought adaptation of BFM.In order to investigate the response of BFM to water stress(WS),we tested four inoculation treatments((no AMF,Control),Glomus mosseae(GM),Glomus intraradices(GI),Glomus mosseae+Glomus intraradices(GMI))in pots,experimented under three field water holding capacity(WHC)of 70%,50%and 30%.The changes of seedling survival rate(SR),AMF relative root length colonization rate(Col),growth,photosynthetic parameters,water status and leaf nutrients were examined.The results showed that under 30%WHC drought conditions,SR with dual inoculation of AMF was not higher than with single inoculation of GM,suggesting that increasing the diversity of AMF did not definitely improve plant SR,and that the species of inoculated AMF might have an important impact on SR.The sensitivity of dual inoculated Col to water stress was lower than that of single inoculation,which was more favorable for dual inoculated BFM seedlings adapting to drought environment.The overall drought resistance ability(D)also showed that dual inoculation of AMF improved plant drought adaptation compared with single inoculation,which was related to the higher Col of dual inoculated AMF.This study is of practical importance to promote vegetation restoration in arid areas in a cost-effective and environmentally friendly manner.展开更多
文摘Cultivation of aerobic granules for simultaneous nitrification and denitrification in two sequencing batch airlift bioreactors was studied. Conventional activated floc and anaerobic granules served as main two inoculated sludge in the systems. Morphological variations of sludge in the reactors were observed. It was found that the cultivation of aerobic granules was closely associated with the kind of inoculated sludge. Round and regular aerobic granules were prevailed in both reactors, and the physical characteristics of the aerobic granules in terms of settling ability, specific gravity, and ratio of water containing were distinct when the inoculate sludge was different. Aerobic granules formed by seeding activated floc are more excellent in simultaneous nitrification and denitrification than that by aerobic granules formed from anaerobic granules. It was concluded that inoculated sludge plays a crucial role in the cultivation of aerobic granules for simultaneous nitrification and denitrification.
基金This work was supported by Chinese National Natural Science Foundation Grants 39928018,30070038 and 30130070, National High-tech Development Project (863 Project) 2001AA215391EU Project QLRT 2000 01441.
文摘Objective To understand the infectious characteristics of a hamster-adapted scrapie strain 263K with five different routes of infection including intracerebral (i.e.), intraperitoneal (i.p.), intragastrical (i.g.), intracardiac and intramuscular (i.m.) approaches. Methods Hamsters were infected with crude- or fine-prepared brain extracts. The neuropathological changes, PrPSc deposits, and patterns of PK-resistant PrP were analyzed by HE stain, immunohistochemistry (IHC) assay and Western blot. Reactive gliosis and neuron loss were evaluated by glial fibrillary acidic protein (GFAP) and neuron specific enolase (NSE) specific IHC. Results The animals inoculated in i.m. and Lp. ways with crude PrPSc extracts showed clinical signs at the average incubation of 69.212.8 and 65.5±3.9 days. Inoculation in i.c. and intracardiac ways with fine PrPSc extracts (0.00035 g) caused similar, but relative long incubation of around 90 days. Only one out of eight hamsters challenged in i.g way with low dosage (0.01 g) became ill after a much longer incubation (185 d), while all animals (4/4) with high dosage (0.04 g) developed clinical signs 105 days postinfection. The most remarkable spongiform degeneration and PrPSc deposits were found in brain stem among the five challenge groups generally. The number of GFAP-positive astrocytes increased distinctly in brain stems in all infection groups, while the number of NSE-positive cells decreased significantly in cerebrum, except i.c. group. The patterns of PK-resistant PrP in brains were basically identical among the five infection routes. Conclusion Typical TSE could be induced in hamsters by inoculating strain 263K in the five infection ways. The incubation periods in bioassays depend on infective dosage, administrating pathway and preparation of PrPSc. The neuropathological changes and PrPSc deposits seem to be related with regions and inoculating pathways.
基金This work was supported by the National Natural Science Foundation of China(51871100).
文摘As a potent nucleating substrate forα-Mg grain,MgAl_(2)O_(4) powder was used to inoculate the Mg-Al melt in this study.The effects of MgAl_(2)O_(4)amount,holding time and Al content on the grain size and grain refining ratio of the inoculated Mg-Al alloys are systematically investigated.The results show that the minimum grain size of Mg-3Al alloy is achieved by adding 2wt.%MgAl_(2)O_(4)powder and this alloy exhibits higher grain refining ratio than Mg-5Al and Mg-8Al alloys.The crystallographic misfit calculation indicates the wellmatching and possible orientation relationships(ORs)betweenα-Mg and MgAl_(2)O_(4).Among these predicted ORs,[10–10]α−Mg//[110]MgAl2O4 in(0002)α−Mg//(1–13)MgAl2O4 possesses the smallest misfit,i.e.,2.34%(fr).Both results of the experiment and crystallographic calculation demonstrate that the grain refinement of Mg-Al alloys is attributed to the MgAl_(2)O_(4)particles acting as the heterogeneous nucleation substrates forα-Mg grains.
文摘The effect of addition of 0.05wt.% to 0.25 wt.% Ca,Zr,Al-FeSi alloy on in-ladle and in-mould inoculation of grey cast irons was investigated.In the present paper,the conclusions drawn are based on thermal analysis.For the solidification pattern,some specific cooling curves characteristics,such as the degree of undercooling at the beginning of eutectic solidif ication and at the end of solidifi cation,as well as the recalescence level,are identif ied to be more influenced by the inoculation technique.The degree of eutectic undercooling of the electrically melted base iron having 0.025% S,0.003% Al and 3.5% Ce is excessively high(39-40℃),generating a relatively high need for inoculation.Under these conditions,the in-mould inoculation has a more signif icant effect compared to ladle inoculation,especially at lower inoculant usage(less than 0.20 wt.%).Generally,the eff iciency of 0.05wt.% -0.15wt.% of alloy for in-mould inoculation is comparable to,or better than,that of 0.15wt.% -0.25wt.% addition in ladle inoculation procedures.In order to secure stable and controlled processes,representative thermal analysis parameters could be used,especially in thin wall grey iron castings production.
文摘The characteristics of some elements in inoculant were analyzed.The effect of the morphology of instantaneous inoculant on its melting velocity was studied.When the inoculants pass through the same sieve number,the volume and the ratio of surface area to volume are different.It is evident from the theoretical analysis and experiment under some conditions that the melting velocity of inoculant depends on the morphology of inoculant.The morphology of inoculant during production should be controlled carefully.
文摘This experiment aimed to evaluate the ruminal degradability in situ of the dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) of Guinea grass silages. The experimental design was completely randomized with six treatments and six repetitions: Guinea grass silage, Guinea grass silage inoculated with 10% wheat bran, Guinea grass silage inoculated with 106 cfu/g of strains of Streptococcus bovis JB1;Guinea grass silage inoculated with 106 cfu/g of strains of Streptococcus bovis JB1 plus 10% of wheat bran;Guinea grass silage inoculated with 106 cfu/g of strains of Streptococcus bovis HC5;Guinea grass silage inoculated with 106 cfu/g of strains of Streptococcus bovis HC5 plus 10% of wheat bran. The silages inoculated with Streptococcus bovis and with added wheat bran resulted in higher values of ruminal degradability of DM, 32.76% and 32.17%, and of crude protein 38.28% and 37.89%. For the effective and potential degradability of DM, CP, NDF and ADF the highest values occurred for silages in these silages as well, in all passage rates. There is a similarity between the responses of Streptococcus bovis JB1 and the HC5, and the wheat bran enhanced the effectiveness of the microbial additive.
文摘Carbide precipitates in Thin Wall Ductile Iron (TWDI) used for automotive applications needs to be eliminated or reduced for improved strength, ductility, crack propagation resistance and good machinability. Ductile iron thin section profiles (≤3 mm) present danger of massive carbide precipitations in the as-cast sample. Precipitated carbide phase is brittle and negatively affects the mechanical properties of the iron matrix. The suppression of carbide formation is associated with the nucleating properties of the nodularizer and innoculant alloys. This treatment is vital in ensuring that carbide precipitation, flake graphite structure and non-nodular graphite phases are reduced or completely eliminated in the TWDI castings. Therefore, the temperature and technique of treatment would influence the yield of the process, and ultimately the mechanical properties. In this study, the effect of nodularization and inoculation treatment temperature on the microstructure and mechanical properties of TWDI castings is examined. The results indicate that good nodularity and nodule count with better percent elongations are achieved using low treatment temperatures in descending order of 1490°C, 1470°C and 1450°C, but have negative effect at lower treatment temperature of 1430°C. However, TWDI castings have superior properties in terms of nodule counts and nodularity at 1450°C. Treatment temperature does not produce significant influence on ultimate tensile strength (UTS) and hardness of TWDI castings. TWDI castings show poor nodularity, nodule count and ductility at higher inoculation treatment temperatures of 1550°C, 1530°C and 1510°C.
文摘<strong>Objectives:</strong> The digestive track of mice and humans has always been an integral part of the pathogenesis of the Trypanosomes but is constantly overlooked. This realization opens up completely new strategies for the development of trypanosomes vaccines, allowing approaches that parenteral delivery forms would not permit. The target of the study was to compare the haematological changes and immunological responses of trypanosomiasis model systems (mice and rats) inoculated orally and intraperitoneally and to observe the afterward effect of a controlled drug [Isometamidium chloride (ISM)] in the restoration of these initial parameters. <strong>Methods:</strong> To achieve this, a total of 40 rodents (20 rats and 20 mice) were purchased, then grouped into two [sixteen younger (1 - 5 weeks) and older (7 - 15 weeks) groups each]. They were further sub-grouped into five each. Body weights, Parasitaemia and Packed Cell Volume (PCV) were taken before, after inoculation and after treatment with ISM at 4 mg/kg. <strong>Results:</strong> Based on presumptive clinical diagnosis, all rodents inoculated intraperitoneally showed clinical signs of fluctuations in weight, PCV and parasitaemia levels before, after inoculations and after treatment compared to those inoculated orally with a significant difference (P < 0.05) observed. Both young and older rodents also responded differently to the inoculants and to the different methods of inoculation. But more deaths were recorded among the mice when compared to the rats. <strong>Conclusion: </strong>Although these non-transgenic models would not have offered a completely new methods to vaccine development, their differences in response to various methods of inoculations is an indication of an exciting research processes and could offer desired results, particularly where transgenic rodents are employed.
基金This work was supported by the National Natural Science Foundation of China(32072399 and 32272641)the Fundamental Research Funds for the Central Universities(GK202201017 and GK202207024)the Program of Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests,China(MIMCP-202203).
文摘Ralstonia solanacearum causes a lethal bacterial wilt disease in many crops,leading to huge losses in crop production every year.Understanding of plant-R.solanacearum interactions will aid to develop efficient strategies to control the disease.As a soilborne pathogen,R.solanacearum naturally infects plants via roots.A huge limitation in studying plant-R.solanacearum interactions is the large variation of R.solanacearum infection assay due to the variable soil conditions and uneven inoculum exposure.Here,we developed a robust and reliable Petri-dish inoculation method which allows consistent and stable infection in young plant seedlings.This method is easy to use,takes about only 10 days from seed germination to the completion of inoculation assay,and requires less inoculum of bacteria as well as growth chamber space.We proved the efficacy of the seedling Petri-dish inoculation method by analyzing plant defense primed by molecular patterns,resistance of defense-related plant mutants,and virulence of R.solanacearum mutants.Furthermore,we demonstrated that the seedling Petri-dish inoculation method can be applied to other host plants such as tobacco and has great potential for high-throughput screening of resistant plant germplasms to bacterial wilt in the future.
文摘The hypereutectic region of grey cast iron has received very little attention especially for designing cast products by researchers. Due to its high carbon equivalence, hypereutectic grey iron poses some challenges especially its tendency for grey to white transition (GWT) at this level of carbon content. However, hypereutectic grey iron possesses inherent properties that could be easily utilized for improved performance in automobile engines and brake pad system. Significantly, they could be modified for superior hardness, strength and toughness. This study presents the effect of microalloying on the mechanical behaviour of hypereutectic grey cast iron with carbon equivalence above 4.5. The first part of this work presented in this paper considers the addition of Cu-Ni and Cu-Ni-Mn to series of as-cast hypereutectic grey cast iron and their hardness and tensile strength were studied and compared. A total of 33 cast samples were obtained with the control sample. The examination of the micrographs revealed that graphite eutectics cells of Type A and A + D were obtained in the resulting microstructure. Results analyses showed that the ferrite forming tendency of silicon was suppressed due to the high carbon content of the as-cast hypereutectic grey iron coupled with the absence of inoculation which plays a great role in the graphite flake type, network, size and distribution. Cu-Ni microalloying was also confirmed to promote hardness with the hardening effect limit of nickel observed at 1.3% composition. For Cu-Mi-Mn addition, excess and free sulphur in the hyper- eutectic grey iron results in reverse effect of manganese on strength, hardness, reduced graphite flake size and shape.
基金supported by the National Key Research and Development Program of China(2017YFC0505104)"135 Project"of Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu,China(SDS–135–1707)。
文摘Bauhinia faberi via.Microphylla(BFM)is an important tree species for vegetation restoration in the dry valley of southwestern China.However,there were few studies on the application of arbuscular mycorrhizal fungi(AMF)in improving the drought adaptation of BFM.In order to investigate the response of BFM to water stress(WS),we tested four inoculation treatments((no AMF,Control),Glomus mosseae(GM),Glomus intraradices(GI),Glomus mosseae+Glomus intraradices(GMI))in pots,experimented under three field water holding capacity(WHC)of 70%,50%and 30%.The changes of seedling survival rate(SR),AMF relative root length colonization rate(Col),growth,photosynthetic parameters,water status and leaf nutrients were examined.The results showed that under 30%WHC drought conditions,SR with dual inoculation of AMF was not higher than with single inoculation of GM,suggesting that increasing the diversity of AMF did not definitely improve plant SR,and that the species of inoculated AMF might have an important impact on SR.The sensitivity of dual inoculated Col to water stress was lower than that of single inoculation,which was more favorable for dual inoculated BFM seedlings adapting to drought environment.The overall drought resistance ability(D)also showed that dual inoculation of AMF improved plant drought adaptation compared with single inoculation,which was related to the higher Col of dual inoculated AMF.This study is of practical importance to promote vegetation restoration in arid areas in a cost-effective and environmentally friendly manner.