Turkey has given importance to the development of the automobile industry since the Ottoman period.While the Ottomans,who were aware of the development process of the automobile industry in the world,provided transpor...Turkey has given importance to the development of the automobile industry since the Ottoman period.While the Ottomans,who were aware of the development process of the automobile industry in the world,provided transportation by horse-drawn carriage,they thought of importing automobiles for the Sultan and high-level bureaucrats in an effort to switch to automobile transportation.However,after the proclamation of the Republic,automobile production started,just like airplanes.While a factory was established for the production of a domestic aircraft,the first automobile production facility was established in Istanbul in 1929 by the American Ford company.This factory was closed after a short time due to the world economic crisis.After the activities of the Kayseri Aircraft Factory,which lasted until 1948,came to an end,this time,Revolution car prototypes could be manufactured completely domestically in 1961.After the project,which did not go into mass production,the KoçGroup started to produce the domestically-made Anadol car with technology transfer from multiple sources in 1967,but the production of Anadol continued until 1984.In 1971,Renault cars started to be produced under the French Renault license,and TOFAŞcars under the Italian FIAT license.Towards the end of the 1970s,creative imitation applications were made in TOFAŞcars with the bird series.In the 1990s,the production of Japanese Honda and Toyota and South Korean Hyundai cars started.In 2011,the idea of producing a domestic automobile emerged,the Devrim automobile was taken as an example in this project,the first Togg prototype was manufactured with technology transfer from multiple sources in December 2018,and it was announced that mass production would begin in March 2023.The 12-year period from 2011 to 2023 is too long for the creation of a domestic automobile.It has been understood that this long process has been passed in order to regain the pre-1980 level of technological ability.However,the most important thing is the transition from the creative imitation stage to the innovation stage.Our wish is that this process can be shortened with phase skipping approaches.展开更多
It is possible to say that the automotive industries of Argentina,Brazil,and Turkey are each developed as an assembly industry and show great similarities to each other in this context.Since the 1980s,the development ...It is possible to say that the automotive industries of Argentina,Brazil,and Turkey are each developed as an assembly industry and show great similarities to each other in this context.Since the 1980s,the development direction of the world automotive industry has been trying to make the country’s investment environment attractive for foreign international companies to produce in their countries in all three countries.However,with the 1980s,their adaptation to the flexible production system and other new technologies being implemented in the Japanese automotive industry took time,meaning that the learning time took a long time,and local contribution rates fell.This has made the slow development mechanism that has been going on since the past work even slower,and they have suffered the punishment for not being able to develop technologies in all three countries by falling behind in the automotive industry.In the 2000s,with technological advances in electric vehicles,when the use of electric vehicles began to become widespread,we can say that all three countries began to experience a new adaptation problem in the automotive industry more severely.In Turkey,this problem was experienced with all its weight along with the other country;in 2006,the policy of attracting foreign investment to the automotive industry was partially abandoned and the approach to producing domestic cars began to be considered,and in 2011,a decision was made to produce domestic cars.As of December 2019,a prototype of the domestic car has been produced by the automobile initiative group of Turkey and work has started for mass production.Thus,the problem of adaptation to the production of electric vehicles was desired to be overcome by moving to a new stage in the path of technology development.The South Korean automotive industry used this approach in the 1980s and was successful and soon gained the ability to develop technology.In order to see the success of the application of this method in Turkey,it is thought that it is necessary to wait for the result of the domestic car project.展开更多
The curriculum development ability of secondary vocational school teachers is a necessary professional ability for teachers.It has important practical significance and practical value for promoting secondary vocationa...The curriculum development ability of secondary vocational school teachers is a necessary professional ability for teachers.It has important practical significance and practical value for promoting secondary vocational education curriculum and teaching reform.On the basis of analyzing the connotation and composition of curriculum development ability of teachers in secondary vocational schools,this article proposes three strategies to improve the curriculum development ability of teachers in secondary vocational schools.展开更多
It is possible to say that each of the Mexican and Turkish automotive industries is developed as an assembly industry and shows great similarities to each other within this framework.However,due to its geographical pr...It is possible to say that each of the Mexican and Turkish automotive industries is developed as an assembly industry and shows great similarities to each other within this framework.However,due to its geographical proximity,the role of US-based automotive companies in the formation of the Mexican automotive industry has become greater,while the Ford Motor company,which entered the US automotive industry in Turkey,was able to take part only with the initiatives of the Otosan company in the 1960s.Another feature of the 1960s is that there were efforts to manufacture domestic cars in Turkey.Since the 1980s,in line with the direction of development of the world automotive industry,Turkey has been trying to make the country’s investment environment attractive for foreign international companies to produce in their countries.In Mexico,even with the possibility of reaching new markets by providing 1990 regional agreements NAFTA ruling party of the Mexican automotive industry,we can say that U.S.firms were largely determined by the direction of development,Turkey’s automotive industry development direction of the company is determined by the first European,then we can say that companies are becoming more efficient in the Far East countries.On the other hand,the US Ford Motor company considered it sufficient to be involved in the Turkey directly.Turkey has decided to return from the policy of attracting foreign investments to its country since 2006,and in 2011 it was decided to produce domestic cars.As of December 2019,a prototype of a domestic car has been produced by the Automobile Enterprise Group of Turkey and work has begun on mass production.Thus,the problem of adaptation to the production of electric vehicles was decided to be overcome by moving to a new stage on the way to technology development.This approach was used by the South Korean automotive industry in the 1980s and was successful,and the ability to develop technology was acquired in a short time.In order to see the success of the application of this method in Turkey,it is thought that it is necessary to wait for the result of the domestic automobile project.Mexico’s policy of opening up more to foreign investments has been successful since the 1990s,and Mexico has become the most productive country in Latin America,surpassing Brazil in automotive industry production.展开更多
As the application undergraduate course colleges and universities, a distinctive talent training system must be formed to achieve the target of practical and innovative talents training, which needs to constantly expl...As the application undergraduate course colleges and universities, a distinctive talent training system must be formed to achieve the target of practical and innovative talents training, which needs to constantly explore and innovate teaching mode. In the paper, talent training model based on the occupation ability development and Excellence Engineer training has carried on the deep discussion and research, thorough study and research.展开更多
BACKGROUND: Generally speaking, anesthesia is often used in gravid body and it has been already proved that many kind of medicine can result in malformation. OBJECTIVE: To explore embryonic skeleton development and ne...BACKGROUND: Generally speaking, anesthesia is often used in gravid body and it has been already proved that many kind of medicine can result in malformation. OBJECTIVE: To explore embryonic skeleton development and neonatal learning and memory of rats anesthetized with pentobarbital sodium in gravid rats. DESIGN: A randomized control trial. SETTING: Laboratory Animal Center of Xuzhou Medical College. MATERIALS: A total of 80 adult female SD rats, of clean grade and weighing 220-240 g, were selected in this study. The main reagents were detailed as follows: pentobarbital sodium (Shanghai Xingzhi Chemical Plant, batch number: 921019); MG-2 maze test apparatus (Zhangjiagang Biomedical Instrument Factory); somatotype microscope (Beijing Taike Instrument Co., Ltd.). METHODS: ① A total of 160 SD rats of half males and females were selected in this study. All rats were copulated. The day that the plug was checked out in the vagina next day was looked as the first day of pregnancy. Gravid rats were divided randomly into four groups, including early anesthesia group, second anesthesia group, late anesthesia group and control group with 20 in each group. Rats in the early anesthesia group were injected with 25 mg/kg soluble pentobarbitone on the 7th day of pregnancy for once; rats in the second anesthesia group were anesthetized with 25 mg/kg soluble pentobarbitone on the 7th and the 14th days of pregnancy for once; rats in the late anesthesia group were anesthetized with 25 mg/kg soluble pentobarbitone on the 14th day of pregnancy for once; rats in the control group did not treat with anything. The time of anesthetizing was controlled in 3 to 4 hours and ether was absorbed while the time was not enough. ② Half of each group was sacrificed on day 20th of pregnancy and the fetus was taken out to be stained with alizarin red S. After stained, the fetal skeleton was examined. The learning and memorizing of one-month rats that were given birth by the rest gravid rats were tested through electric mare method. Determine their study ability according to their correct rate of 90% or above of arrival at the safe area in 20 s. After they finally learned to arrive at the safe area correctly, test them once more in 24 hours and record the correct rate of 15 times. MAIN OUTCOME MEASURES: The rate of malformation in fetus and ability of learning and memory in one-month rats. RESULTS: A total of 80 female rats were anesthetized in this experiment. Totally 490 immature rats were tested with maze testing machine and 196 fetuses were stained with alizarin red S to observe the development of their skeleton. However, one of the 80 female rats was led to death because of overdose. ① Malformation experiment: Learning ability of second anesthesia group was evidently different from the control group while the other two groups were not in the electric mare method. The fetal skeleton malformation rate of three experimental groups was 87.0%, 60.9% and 17.9%, respectively, while it was 5.6% in the control group. ② Electric mare method: Times of rats which arrived at the safe regions were respectively 49.0±31.0, 68.0±35.0, 47.0±31.0 and 44.0±21.0 in early anesthesia group, second anesthesia group, late anesthesia group and control group; and then, there was significant difference between the second anesthesia group and the control group (P < 0.05). Exact rates of memory of rats were respectively (64.36±14.35)%, (62.15±18.33)%, (54.19±12.28)% and (68.24±15.91)% in early anesthesia group, second anesthesia group, late anesthesia group and control group; and then, there were no significant differences as compared with the control group (P > 0.05). CONCLUSION: The influence of anesthesia with pentobarbital sodium is obvious in fetal skeleton development and learning and memory ability.展开更多
Sustainable performance is expected to become a major factor when examining the feasibility of a construction project in terms of its life cycle performance. The study on which this paper is based developed a simulati...Sustainable performance is expected to become a major factor when examining the feasibility of a construction project in terms of its life cycle performance. The study on which this paper is based developed a simulation model, using system dy- namics methodology, to assess the sustainable performance of projects. Three major factors are used to examine project sus- tainable performance (PSP): the sustainability of economic development (E), the sustainability of social development (S), and the sustainability of environmental development (En). Sustainable development ability (SDA) was used as a prototype to evaluate the degree of sustainable performance. The simulation software ‘ithink’ was used to help with the application of the model to a real life case. This paper explains and demonstrates the procedures used to develop the model and finally offers an approach for assessing the feasibility of a construction project in terms of its sustainable performance.展开更多
To meet society’s needs for undergraduate students to have engineering skills and to develop students’ability to operate Linux and engage in network software development,this paper proposes the construction of a new...To meet society’s needs for undergraduate students to have engineering skills and to develop students’ability to operate Linux and engage in network software development,this paper proposes the construction of a new specialized course for network engineering major--Linux system and network programming.This paper analyzes the course’s advantages,presents the contents of this course,designs a series of teaching methods aimed at improving students’engineering ability,proposes a course assessment method that will encourage students to practice,lists the development requirements for an examination software designed for this course,and finally,presents the results of our practice in teaching this course.展开更多
Through scientific researches and analysis of large quantities of detailed data of Northwestern China’s (NWC). The article illustrates position and present situation and advantages of NWC in Chinese economic developi...Through scientific researches and analysis of large quantities of detailed data of Northwestern China’s (NWC). The article illustrates position and present situation and advantages of NWC in Chinese economic developing, and studies the development opportvnities and challenges facing the NWC. factly, on the basic of the above analysic. The paper puts forword the development model and development means in the NWC.展开更多
This paper will first focus on a brief evaluation ofthe teacher-centered and the learner-centered method-ologies.Then,it presents the practical ways of teach-ing based on the learner-centered approach in class-rooms t...This paper will first focus on a brief evaluation ofthe teacher-centered and the learner-centered method-ologies.Then,it presents the practical ways of teach-ing based on the learner-centered approach in class-rooms to show how students’initiative is given fullplay.Finally,it presents the guidance from fellowstudents and teachers in group activitis.The purposeof the learner-centered approach is to develop students’communicative展开更多
This study aimed to evaluate the effect of repeated ovarian stimulation(OS)on the ovarian follicular population and morphology in female mice and its influence on the embryo’s developmental ability,and the profile of t...This study aimed to evaluate the effect of repeated ovarian stimulation(OS)on the ovarian follicular population and morphology in female mice and its influence on the embryo’s developmental ability,and the profile of the ovarian surface epithelium(OSE).A total of 75 mice were enrolled in this experiment and randomly assigned into three groups:repeated ovarian stimulated group[n=25;receiving 5 IU pregnant mare serum gonadotrophin(PMSG)and human chorionic gonadotro-pin(hCG)at 6 day intervals for 5 cycles];single ovarian stimulated group(n=25;receiving 5 IU PMSG and hCG for 1 cycle),and control group(n=25;without additional treatment).The follicle number at various stages and the morphologies were recorded respectively in the three groups.The harvested oocytes or embryos,cleavage rate,good quality embryo rate,and blastocyst production rate were counted and calculated,and the proliferations of ovarian surface epithelium were evaluated respectively.In the three groups,the single ovarian stimulation treatment significantly increased the mean number of ovarian oocytes or embryos(39.25�10.77 one-cell embryos/female);on the other hand,repeated gonadotropin stimulation obtained the lowest mean number(5.15�2.81 eggs/female,P<0.01).Repeated ovarian stimulation also tended to decrease normal follicles of primary follicles(66.67%)and secondary follicles(72.86%),and got the lowest cleavage rate(67.47%),lowest good quality embryo rate(2.41%),and lowest blastocyst production rate(0).The OSE cells adjacent to the antral follicles and corpus luteum(CL)in the repeated ovarian stimulated group(81.8%)had a significantly higher proliferation rate than the other groups.The proliferation rate of the OSE in the single ovarian stimulated group(56.4%)was signifi-cantly higher than that in the control group(37.5%)(P<0.01).In conclusion,single ovarian stimulation may produce more oocytes/embryos.However,repeated gona-dotropin stimulation may have a negative effect on the ovarian follicular quality,the number of mature retrieved oocytes,and the embryo quality,even increasing the chance of ovarian cancer.展开更多
Following fertilization in mammals, the zygote initiates the developmental program, which has a transient capacity to generate cell types of both embryonic and extraembryonic lineages, which is defined as totipotency ...Following fertilization in mammals, the zygote initiates the developmental program, which has a transient capacity to generate cell types of both embryonic and extraembryonic lineages, which is defined as totipotency (Condic, 2014). In mice,only zygotes and blastomeres of 2-cell stage embryos are considered totipotent, since they have the ability to develop into a full展开更多
文摘Turkey has given importance to the development of the automobile industry since the Ottoman period.While the Ottomans,who were aware of the development process of the automobile industry in the world,provided transportation by horse-drawn carriage,they thought of importing automobiles for the Sultan and high-level bureaucrats in an effort to switch to automobile transportation.However,after the proclamation of the Republic,automobile production started,just like airplanes.While a factory was established for the production of a domestic aircraft,the first automobile production facility was established in Istanbul in 1929 by the American Ford company.This factory was closed after a short time due to the world economic crisis.After the activities of the Kayseri Aircraft Factory,which lasted until 1948,came to an end,this time,Revolution car prototypes could be manufactured completely domestically in 1961.After the project,which did not go into mass production,the KoçGroup started to produce the domestically-made Anadol car with technology transfer from multiple sources in 1967,but the production of Anadol continued until 1984.In 1971,Renault cars started to be produced under the French Renault license,and TOFAŞcars under the Italian FIAT license.Towards the end of the 1970s,creative imitation applications were made in TOFAŞcars with the bird series.In the 1990s,the production of Japanese Honda and Toyota and South Korean Hyundai cars started.In 2011,the idea of producing a domestic automobile emerged,the Devrim automobile was taken as an example in this project,the first Togg prototype was manufactured with technology transfer from multiple sources in December 2018,and it was announced that mass production would begin in March 2023.The 12-year period from 2011 to 2023 is too long for the creation of a domestic automobile.It has been understood that this long process has been passed in order to regain the pre-1980 level of technological ability.However,the most important thing is the transition from the creative imitation stage to the innovation stage.Our wish is that this process can be shortened with phase skipping approaches.
文摘It is possible to say that the automotive industries of Argentina,Brazil,and Turkey are each developed as an assembly industry and show great similarities to each other in this context.Since the 1980s,the development direction of the world automotive industry has been trying to make the country’s investment environment attractive for foreign international companies to produce in their countries in all three countries.However,with the 1980s,their adaptation to the flexible production system and other new technologies being implemented in the Japanese automotive industry took time,meaning that the learning time took a long time,and local contribution rates fell.This has made the slow development mechanism that has been going on since the past work even slower,and they have suffered the punishment for not being able to develop technologies in all three countries by falling behind in the automotive industry.In the 2000s,with technological advances in electric vehicles,when the use of electric vehicles began to become widespread,we can say that all three countries began to experience a new adaptation problem in the automotive industry more severely.In Turkey,this problem was experienced with all its weight along with the other country;in 2006,the policy of attracting foreign investment to the automotive industry was partially abandoned and the approach to producing domestic cars began to be considered,and in 2011,a decision was made to produce domestic cars.As of December 2019,a prototype of the domestic car has been produced by the automobile initiative group of Turkey and work has started for mass production.Thus,the problem of adaptation to the production of electric vehicles was desired to be overcome by moving to a new stage in the path of technology development.The South Korean automotive industry used this approach in the 1980s and was successful and soon gained the ability to develop technology.In order to see the success of the application of this method in Turkey,it is thought that it is necessary to wait for the result of the domestic car project.
基金School-level scientific research development fund project of Jilin Engineering Normal University"Research on the current situation and promotion strategy of curriculum development ability of secondary vocational teachers in Jilin Province"(X2015046).
文摘The curriculum development ability of secondary vocational school teachers is a necessary professional ability for teachers.It has important practical significance and practical value for promoting secondary vocational education curriculum and teaching reform.On the basis of analyzing the connotation and composition of curriculum development ability of teachers in secondary vocational schools,this article proposes three strategies to improve the curriculum development ability of teachers in secondary vocational schools.
文摘It is possible to say that each of the Mexican and Turkish automotive industries is developed as an assembly industry and shows great similarities to each other within this framework.However,due to its geographical proximity,the role of US-based automotive companies in the formation of the Mexican automotive industry has become greater,while the Ford Motor company,which entered the US automotive industry in Turkey,was able to take part only with the initiatives of the Otosan company in the 1960s.Another feature of the 1960s is that there were efforts to manufacture domestic cars in Turkey.Since the 1980s,in line with the direction of development of the world automotive industry,Turkey has been trying to make the country’s investment environment attractive for foreign international companies to produce in their countries.In Mexico,even with the possibility of reaching new markets by providing 1990 regional agreements NAFTA ruling party of the Mexican automotive industry,we can say that U.S.firms were largely determined by the direction of development,Turkey’s automotive industry development direction of the company is determined by the first European,then we can say that companies are becoming more efficient in the Far East countries.On the other hand,the US Ford Motor company considered it sufficient to be involved in the Turkey directly.Turkey has decided to return from the policy of attracting foreign investments to its country since 2006,and in 2011 it was decided to produce domestic cars.As of December 2019,a prototype of a domestic car has been produced by the Automobile Enterprise Group of Turkey and work has begun on mass production.Thus,the problem of adaptation to the production of electric vehicles was decided to be overcome by moving to a new stage on the way to technology development.This approach was used by the South Korean automotive industry in the 1980s and was successful,and the ability to develop technology was acquired in a short time.In order to see the success of the application of this method in Turkey,it is thought that it is necessary to wait for the result of the domestic automobile project.Mexico’s policy of opening up more to foreign investments has been successful since the 1990s,and Mexico has become the most productive country in Latin America,surpassing Brazil in automotive industry production.
文摘As the application undergraduate course colleges and universities, a distinctive talent training system must be formed to achieve the target of practical and innovative talents training, which needs to constantly explore and innovate teaching mode. In the paper, talent training model based on the occupation ability development and Excellence Engineer training has carried on the deep discussion and research, thorough study and research.
文摘BACKGROUND: Generally speaking, anesthesia is often used in gravid body and it has been already proved that many kind of medicine can result in malformation. OBJECTIVE: To explore embryonic skeleton development and neonatal learning and memory of rats anesthetized with pentobarbital sodium in gravid rats. DESIGN: A randomized control trial. SETTING: Laboratory Animal Center of Xuzhou Medical College. MATERIALS: A total of 80 adult female SD rats, of clean grade and weighing 220-240 g, were selected in this study. The main reagents were detailed as follows: pentobarbital sodium (Shanghai Xingzhi Chemical Plant, batch number: 921019); MG-2 maze test apparatus (Zhangjiagang Biomedical Instrument Factory); somatotype microscope (Beijing Taike Instrument Co., Ltd.). METHODS: ① A total of 160 SD rats of half males and females were selected in this study. All rats were copulated. The day that the plug was checked out in the vagina next day was looked as the first day of pregnancy. Gravid rats were divided randomly into four groups, including early anesthesia group, second anesthesia group, late anesthesia group and control group with 20 in each group. Rats in the early anesthesia group were injected with 25 mg/kg soluble pentobarbitone on the 7th day of pregnancy for once; rats in the second anesthesia group were anesthetized with 25 mg/kg soluble pentobarbitone on the 7th and the 14th days of pregnancy for once; rats in the late anesthesia group were anesthetized with 25 mg/kg soluble pentobarbitone on the 14th day of pregnancy for once; rats in the control group did not treat with anything. The time of anesthetizing was controlled in 3 to 4 hours and ether was absorbed while the time was not enough. ② Half of each group was sacrificed on day 20th of pregnancy and the fetus was taken out to be stained with alizarin red S. After stained, the fetal skeleton was examined. The learning and memorizing of one-month rats that were given birth by the rest gravid rats were tested through electric mare method. Determine their study ability according to their correct rate of 90% or above of arrival at the safe area in 20 s. After they finally learned to arrive at the safe area correctly, test them once more in 24 hours and record the correct rate of 15 times. MAIN OUTCOME MEASURES: The rate of malformation in fetus and ability of learning and memory in one-month rats. RESULTS: A total of 80 female rats were anesthetized in this experiment. Totally 490 immature rats were tested with maze testing machine and 196 fetuses were stained with alizarin red S to observe the development of their skeleton. However, one of the 80 female rats was led to death because of overdose. ① Malformation experiment: Learning ability of second anesthesia group was evidently different from the control group while the other two groups were not in the electric mare method. The fetal skeleton malformation rate of three experimental groups was 87.0%, 60.9% and 17.9%, respectively, while it was 5.6% in the control group. ② Electric mare method: Times of rats which arrived at the safe regions were respectively 49.0±31.0, 68.0±35.0, 47.0±31.0 and 44.0±21.0 in early anesthesia group, second anesthesia group, late anesthesia group and control group; and then, there was significant difference between the second anesthesia group and the control group (P < 0.05). Exact rates of memory of rats were respectively (64.36±14.35)%, (62.15±18.33)%, (54.19±12.28)% and (68.24±15.91)% in early anesthesia group, second anesthesia group, late anesthesia group and control group; and then, there were no significant differences as compared with the control group (P > 0.05). CONCLUSION: The influence of anesthesia with pentobarbital sodium is obvious in fetal skeleton development and learning and memory ability.
基金Project supported by the Research Grant Council of Hong Kong,China
文摘Sustainable performance is expected to become a major factor when examining the feasibility of a construction project in terms of its life cycle performance. The study on which this paper is based developed a simulation model, using system dy- namics methodology, to assess the sustainable performance of projects. Three major factors are used to examine project sus- tainable performance (PSP): the sustainability of economic development (E), the sustainability of social development (S), and the sustainability of environmental development (En). Sustainable development ability (SDA) was used as a prototype to evaluate the degree of sustainable performance. The simulation software ‘ithink’ was used to help with the application of the model to a real life case. This paper explains and demonstrates the procedures used to develop the model and finally offers an approach for assessing the feasibility of a construction project in terms of its sustainable performance.
基金supported by the Teaching Research and Reform Project of Qingdao University of Technology under Grant 2024-10335040。
文摘To meet society’s needs for undergraduate students to have engineering skills and to develop students’ability to operate Linux and engage in network software development,this paper proposes the construction of a new specialized course for network engineering major--Linux system and network programming.This paper analyzes the course’s advantages,presents the contents of this course,designs a series of teaching methods aimed at improving students’engineering ability,proposes a course assessment method that will encourage students to practice,lists the development requirements for an examination software designed for this course,and finally,presents the results of our practice in teaching this course.
文摘Through scientific researches and analysis of large quantities of detailed data of Northwestern China’s (NWC). The article illustrates position and present situation and advantages of NWC in Chinese economic developing, and studies the development opportvnities and challenges facing the NWC. factly, on the basic of the above analysic. The paper puts forword the development model and development means in the NWC.
文摘This paper will first focus on a brief evaluation ofthe teacher-centered and the learner-centered method-ologies.Then,it presents the practical ways of teach-ing based on the learner-centered approach in class-rooms to show how students’initiative is given fullplay.Finally,it presents the guidance from fellowstudents and teachers in group activitis.The purposeof the learner-centered approach is to develop students’communicative
基金supported by the Special Funds for State Key Development Program for Basic Research of China(973 Program)(No.2007CB948104).
文摘This study aimed to evaluate the effect of repeated ovarian stimulation(OS)on the ovarian follicular population and morphology in female mice and its influence on the embryo’s developmental ability,and the profile of the ovarian surface epithelium(OSE).A total of 75 mice were enrolled in this experiment and randomly assigned into three groups:repeated ovarian stimulated group[n=25;receiving 5 IU pregnant mare serum gonadotrophin(PMSG)and human chorionic gonadotro-pin(hCG)at 6 day intervals for 5 cycles];single ovarian stimulated group(n=25;receiving 5 IU PMSG and hCG for 1 cycle),and control group(n=25;without additional treatment).The follicle number at various stages and the morphologies were recorded respectively in the three groups.The harvested oocytes or embryos,cleavage rate,good quality embryo rate,and blastocyst production rate were counted and calculated,and the proliferations of ovarian surface epithelium were evaluated respectively.In the three groups,the single ovarian stimulation treatment significantly increased the mean number of ovarian oocytes or embryos(39.25�10.77 one-cell embryos/female);on the other hand,repeated gonadotropin stimulation obtained the lowest mean number(5.15�2.81 eggs/female,P<0.01).Repeated ovarian stimulation also tended to decrease normal follicles of primary follicles(66.67%)and secondary follicles(72.86%),and got the lowest cleavage rate(67.47%),lowest good quality embryo rate(2.41%),and lowest blastocyst production rate(0).The OSE cells adjacent to the antral follicles and corpus luteum(CL)in the repeated ovarian stimulated group(81.8%)had a significantly higher proliferation rate than the other groups.The proliferation rate of the OSE in the single ovarian stimulated group(56.4%)was signifi-cantly higher than that in the control group(37.5%)(P<0.01).In conclusion,single ovarian stimulation may produce more oocytes/embryos.However,repeated gona-dotropin stimulation may have a negative effect on the ovarian follicular quality,the number of mature retrieved oocytes,and the embryo quality,even increasing the chance of ovarian cancer.
基金supported by the National Natural Science Foundation of China (Nos. 31621004 and 81571356)the Key Research Projects of the Frontier Science of the Chinese Academy of Sciences (QYZDY-SSWSMC002)+1 种基金the Key Deployment Projects of the Chinese Academy of Sciences (ZDRW-ZS-2017-5)the Youth Innovation Promotion Association CAS (No. 2017113)
文摘Following fertilization in mammals, the zygote initiates the developmental program, which has a transient capacity to generate cell types of both embryonic and extraembryonic lineages, which is defined as totipotency (Condic, 2014). In mice,only zygotes and blastomeres of 2-cell stage embryos are considered totipotent, since they have the ability to develop into a full