[ Objective] To study the correlation between HI titer and protection against IBV challenge in SPF layers. [ Method ] SPF layers were randomly divided into four groups, namely group A1, A2, B1 and B2. The group A1 was...[ Objective] To study the correlation between HI titer and protection against IBV challenge in SPF layers. [ Method ] SPF layers were randomly divided into four groups, namely group A1, A2, B1 and B2. The group A1 was immunized with H120 live vaccine. The group A2 was first immunized with H120 live vaccine and later boosted with ND-IB-EDS trivalent inactivated vaccine. The group B1 was used as unimmunized chal- lenge control. The group B2 was kept as unimmunized unchallenged control. The blood samples were taken prior and post-vaccination at intervals and HI tests were conducted. At the laying peak, the group A1, A2 and B1 were challenged with IBV M4t virulent strain. The clinical features and egg production of layers were monitored and recorded. [Result] After 30 d post vaccination with H120 live vaccine, the HI titer reached 4.45 log2; after 30 days boosting with ND-IB-EDS trivalent inactivated vaccine, the HI titer reached to 7.35 log2. Before challenge, HI antibody titer in group A1, A2, B1 and B2 were respectively 4.24 log2, 7.40 Iog2, 2.10 log2 and 2.10 log2. After challenge, chickens in unimmunized challenge control group B1 showed respiratory symptoms, egg production dropped by 30.9%, and they produced more soft-shelled, no-shelled or abnormal eggs. In the group A1, some chickens had light respiratory symptoms and egg production dropped by 11.7%. In the group A2, the egg production of all chickens was as normal as the group B2. [ Conclusion] When the HI titer was over 6 log2, challenge by virulent virus had no impact on egg produc- tion; when the HI titer was 5 log2, 4 log2 and less 3 log2, egg production dropped by 6.0%, 11.3% and 29.6%, respectively. Thus, the HI anti- body level in chickens has close correlation with protection against IBV challenge.展开更多
The Environmental Protection Tax Law that took effect in 2018 gave local authorities a certain amount of discretionary power to set the local rates for environmental protection tax.The inter-provincial gradient tax ra...The Environmental Protection Tax Law that took effect in 2018 gave local authorities a certain amount of discretionary power to set the local rates for environmental protection tax.The inter-provincial gradient tax rates pattern may induce strategic relocation of enterprises,leading to unintended policy results.Combined with the data on trans-regional investment of listed companies,this paper employs the Difference-in-Difference(DID)approach to study the impact of inter-provincially different environmental tax rates on the trans-regional migration of polluting enterprises.The study shows that due to the regional differences in the tax rates,the polluting enterprises opt for the relocation strategy of"avoiding high tax rates and opting for low rates",setting up more subsidiaries in regions with relatively low tax rates.Further research demonstrates that the trans-regional migration induced by different tax rates can help reduce production costs and increase corporate profits,while dampening the corporate enthusiasm for green innovation in the short term and resulting in pollution transfer.This paper reveals the unintended policy effects that may derive from the environmental tax reform,providing concrete proof for the comprehensive evaluation and understanding of the actual policy effects of existing environmental tax reform.展开更多
In order to demonstrate the long term protective efficacy and immunologic persistence of domestically made hepatitis B plasma derived vaccine, 371 children had been followed up for 5 to 8 years after primary vacci...In order to demonstrate the long term protective efficacy and immunologic persistence of domestically made hepatitis B plasma derived vaccine, 371 children had been followed up for 5 to 8 years after primary vaccination (10 μg×3). The results showed that the positive rate of antibody to hepatitis B surface antigen (anti HBs) in 371 subjects was 77.6% and the geometric mean titre (GMT) of anti HBs was 47.32 IU/L. The anti HBs positive rates in the subjects who had been vaccined for five, six, seven and eight years remained 83.91%, 73.68%, 81.25% and 72.24%, respectively, while the GMTs were 59.53, 43.64, 42.21 and 46.20 IU/L, respectively. The protective efficacy rate of hepatitis B vaccine was 94.26% if both HBsAg and anti HBc were considered as infective indicators, and 88.28%, if only HBsAg positive cases were taken into account. The study indicated that the domestically made hepatitis B vaccine could provide at least 5 to 8 years protection against hepatitis B infection.展开更多
Background:Mosquitoes have developed resistance against pyrethroids,the only class of insecticides approved for use on long-lasting insecticidal nets(LLINs).The present study sought to evaluate the efficacy of the pyr...Background:Mosquitoes have developed resistance against pyrethroids,the only class of insecticides approved for use on long-lasting insecticidal nets(LLINs).The present study sought to evaluate the efficacy of the pyrethroid synergist PermaNet^(■)3.0 LLIN versus the pyrethroid-only PermaNet^(■)2.0 LLIN,in an East African hut design in Lower Moshi,northern Tanzania.In this setting,resistance to pyrethroid insecticides has been identified in Anopheles gambiae mosquitoes.Methods:Standard World Health Organization bioefficacy evaluations were conducted in both laboratory and experimental huts.Experimental hut evaluations were conducted in an area where there was presence of a population of highly pyrethroid-resistant An.arabiensis mosquitoes.All nets used were subjected to cone bioassays and then to experimental hut trials.Mosquito mortality,blood-feeding inhibition and personal protection rate were compared between untreated nets,unwashed LLINs and LLINs that were washed 20 times.Results:Both washed and unwashed PermaNet^(■)2.0 and PermaNet^(■)3.0 LLINs had knockdown and mortality rates of 100%against a susceptible strain of An.gambiae sensu stricto.The adjusted mortality rate of the wild mosquito population after use of the unwashed PermaNet^(■)3.0 and PermaNet^(■)2.0 nets was found to be higher than after use of the washed PermaNet^(■)2.0 and PermaNet^(■)3.0 nets.Conclusions:Given the increasing incidence of pyrethroid resistance in An.gambiae mosquitoes in Tanzania,we recommend that consideration is given to its distribution in areas with pyrethroid-resistant malaria vectors within the framework of a national insecticide-resistance management plan.展开更多
文摘[ Objective] To study the correlation between HI titer and protection against IBV challenge in SPF layers. [ Method ] SPF layers were randomly divided into four groups, namely group A1, A2, B1 and B2. The group A1 was immunized with H120 live vaccine. The group A2 was first immunized with H120 live vaccine and later boosted with ND-IB-EDS trivalent inactivated vaccine. The group B1 was used as unimmunized chal- lenge control. The group B2 was kept as unimmunized unchallenged control. The blood samples were taken prior and post-vaccination at intervals and HI tests were conducted. At the laying peak, the group A1, A2 and B1 were challenged with IBV M4t virulent strain. The clinical features and egg production of layers were monitored and recorded. [Result] After 30 d post vaccination with H120 live vaccine, the HI titer reached 4.45 log2; after 30 days boosting with ND-IB-EDS trivalent inactivated vaccine, the HI titer reached to 7.35 log2. Before challenge, HI antibody titer in group A1, A2, B1 and B2 were respectively 4.24 log2, 7.40 Iog2, 2.10 log2 and 2.10 log2. After challenge, chickens in unimmunized challenge control group B1 showed respiratory symptoms, egg production dropped by 30.9%, and they produced more soft-shelled, no-shelled or abnormal eggs. In the group A1, some chickens had light respiratory symptoms and egg production dropped by 11.7%. In the group A2, the egg production of all chickens was as normal as the group B2. [ Conclusion] When the HI titer was over 6 log2, challenge by virulent virus had no impact on egg produc- tion; when the HI titer was 5 log2, 4 log2 and less 3 log2, egg production dropped by 6.0%, 11.3% and 29.6%, respectively. Thus, the HI anti- body level in chickens has close correlation with protection against IBV challenge.
基金Major Project of the National Social Science Fund of China"Research on Local Financial System Reform in the Development of Equal Access to Basic Public Services"(18ZDA096)the Sci-Tech Innovation Program for Postgraduates of Department of Finance at the School of Economics of Xiamen University"Research on Financial Pressure and Coping Strategies of Local Governments".The authors would like to express appreciation for the valuable suggestions from anonymous reviewers and the editorial department.The authors take sole responsibility for the paper.
文摘The Environmental Protection Tax Law that took effect in 2018 gave local authorities a certain amount of discretionary power to set the local rates for environmental protection tax.The inter-provincial gradient tax rates pattern may induce strategic relocation of enterprises,leading to unintended policy results.Combined with the data on trans-regional investment of listed companies,this paper employs the Difference-in-Difference(DID)approach to study the impact of inter-provincially different environmental tax rates on the trans-regional migration of polluting enterprises.The study shows that due to the regional differences in the tax rates,the polluting enterprises opt for the relocation strategy of"avoiding high tax rates and opting for low rates",setting up more subsidiaries in regions with relatively low tax rates.Further research demonstrates that the trans-regional migration induced by different tax rates can help reduce production costs and increase corporate profits,while dampening the corporate enthusiasm for green innovation in the short term and resulting in pollution transfer.This paper reveals the unintended policy effects that may derive from the environmental tax reform,providing concrete proof for the comprehensive evaluation and understanding of the actual policy effects of existing environmental tax reform.
文摘In order to demonstrate the long term protective efficacy and immunologic persistence of domestically made hepatitis B plasma derived vaccine, 371 children had been followed up for 5 to 8 years after primary vaccination (10 μg×3). The results showed that the positive rate of antibody to hepatitis B surface antigen (anti HBs) in 371 subjects was 77.6% and the geometric mean titre (GMT) of anti HBs was 47.32 IU/L. The anti HBs positive rates in the subjects who had been vaccined for five, six, seven and eight years remained 83.91%, 73.68%, 81.25% and 72.24%, respectively, while the GMTs were 59.53, 43.64, 42.21 and 46.20 IU/L, respectively. The protective efficacy rate of hepatitis B vaccine was 94.26% if both HBsAg and anti HBc were considered as infective indicators, and 88.28%, if only HBsAg positive cases were taken into account. The study indicated that the domestically made hepatitis B vaccine could provide at least 5 to 8 years protection against hepatitis B infection.
基金The study was financially supported by Vestergaard Frandsen,Aarhus,Denmark.The funding body had no influence on this publication.
文摘Background:Mosquitoes have developed resistance against pyrethroids,the only class of insecticides approved for use on long-lasting insecticidal nets(LLINs).The present study sought to evaluate the efficacy of the pyrethroid synergist PermaNet^(■)3.0 LLIN versus the pyrethroid-only PermaNet^(■)2.0 LLIN,in an East African hut design in Lower Moshi,northern Tanzania.In this setting,resistance to pyrethroid insecticides has been identified in Anopheles gambiae mosquitoes.Methods:Standard World Health Organization bioefficacy evaluations were conducted in both laboratory and experimental huts.Experimental hut evaluations were conducted in an area where there was presence of a population of highly pyrethroid-resistant An.arabiensis mosquitoes.All nets used were subjected to cone bioassays and then to experimental hut trials.Mosquito mortality,blood-feeding inhibition and personal protection rate were compared between untreated nets,unwashed LLINs and LLINs that were washed 20 times.Results:Both washed and unwashed PermaNet^(■)2.0 and PermaNet^(■)3.0 LLINs had knockdown and mortality rates of 100%against a susceptible strain of An.gambiae sensu stricto.The adjusted mortality rate of the wild mosquito population after use of the unwashed PermaNet^(■)3.0 and PermaNet^(■)2.0 nets was found to be higher than after use of the washed PermaNet^(■)2.0 and PermaNet^(■)3.0 nets.Conclusions:Given the increasing incidence of pyrethroid resistance in An.gambiae mosquitoes in Tanzania,we recommend that consideration is given to its distribution in areas with pyrethroid-resistant malaria vectors within the framework of a national insecticide-resistance management plan.
