To analyse the association between isoflavone intake and ulcerative colitis motility symptoms in individuals in remission. METHODSCross-sectional study was conducted in a group of ulcerative colitis remission individu...To analyse the association between isoflavone intake and ulcerative colitis motility symptoms in individuals in remission. METHODSCross-sectional study was conducted in a group of ulcerative colitis remission individuals, in sub-groups characterised by various intestinal motility and functioning characteristics (abdominal pain, flatulence, constipations, tenesmus). Total of 56 individuals with ulcerative colitis in remission (19 males and 37 females) were recruited for the study. Assessment of diet was based on self-reported data from each patient’s dietary records taken over a period of three typical, random days (2 weekdays and 1 d of the weekend). The daily isoflavone intake (daidzein, genistein, glycitein and total isoflavones) and daily isoflavone intake per 1000 kcal of diet were assessed. RESULTSNo correlations between isoflavone intake levels and number of bowel movements per day were observed both in the case of intake and intake per 1000 kcal of diet. In the group of individuals declaring lack of abdominal pain, the higher intakes of daidzein (P = 0.0075), daidzein per 1000 kcal of diet (P = 0.0358) and total isoflavone (P = 0.0358) were stated, than in the group of individuals declaring abdominal pain. In the group of individuals declaring lack of constipations, the lower intakes of glycitein (P = 0.0213) and glycitein per 1000 kcal of diet (P = 0.0213) were stated, than in the group of individuals declaring presence of constipations. No differences were observed in isoflavone intake between groups of ulcerative colitis individuals declaring lack of flatulence and declaring presence of flatulence, as well as between groups declaring lack of tenesmus and declaring presence of tenesmus. CONCLUSIONThe moderate dietary isoflavone intake may be beneficial for individuals with ulcerative colitis in remission, however, before including it into recommendations, further prospective studies are needed.展开更多
We cloned and expressed bile salt hydrolase gene ofLactobacillus plantarum M1-UVS29 in Lactococcus lactis NZ9000 successfully. Gene-specific primers for amplification of L. plantarum bsh were designed by using sequenc...We cloned and expressed bile salt hydrolase gene ofLactobacillus plantarum M1-UVS29 in Lactococcus lactis NZ9000 successfully. Gene-specific primers for amplification of L. plantarum bsh were designed by using sequence which availabled from GenBank. The production of PCR amplicon was confirmed by sequencing and cloned into pMD18-T vector, and then recombined into expression vector pNZ8148 and yielding vector pNZ8148-BSH, pNZ8148-BSH was transferred into Lactococcus lactis NZ9000. Sequencing indicated that the cloned bsh fragment contained 995 nucleotides, and shared 99.3% sequence homology with bsh gene from L. plantarum MBUL10. Cloned bsh fragment was successfully transduced into NICE expression system and confirmed by PCR and restriction digest. Recombinant BSH protein was analyzed by SDS-PAGE. The molecular weight of BSH protein was approximately 37 ku. Activity of the expressed protein was 0.77 μmol· min^-1. The successfully expressed proteins by genetic engineering technology made the function of lactic acid bacteria be abundant and laid the foundation for further researches into cholesterol-lowering lactic acid bacterium food and probiotics.展开更多
Radio Frequency IDentification(RFID)and related technologies such as Near Field Communication(NFC)are becoming essential in industrial contexts thanks to their ability to perform contactless data exchange,either devic...Radio Frequency IDentification(RFID)and related technologies such as Near Field Communication(NFC)are becoming essential in industrial contexts thanks to their ability to perform contactless data exchange,either device-to-device or tag-to-device.One of the three main operation modes of NFC,called read/write mode,makes use of the latter type of interaction.It is extensively used in business information systems that make use of NFC tags to provide the end-user with augmented information in one of several available NFC data exchange formats,such as plain text,simple URLs or enriched URLs.Using a wide variety of physical form factors,NFC-compatible tags(wireless transponders)are currently available in many locations with applications going from smart posters,contactless tokens,tap-and-go payments or transport ticketing to automated device configuration,patient identification at hospitals or inventory management within supply chains.Most of these applications handle sensitive processes or data.This paper proposes a complete security threat model for the read/write operation mode of NFC used in Next Generation Industrial IoT(Nx-IIoT)contexts.This model,based on a wellknown methodology,STRIDE,allows developers and users to identify NFC applications vulnerabilities or weaknesses,analyze potential threats,propose risk management strategies,and design mitigation mechanisms to mention only some significant examples.展开更多
We present fast fourth-order finite difference scheme for 3D Helmholtz equation with Neumann boundary condition. We employ the discrete Fourier transform operator and divide the problem into some independent subproble...We present fast fourth-order finite difference scheme for 3D Helmholtz equation with Neumann boundary condition. We employ the discrete Fourier transform operator and divide the problem into some independent subproblems. By means of the Gaussian elimination in the vertical direction, the problem is reduced into a small system on the top layer of the domain. The procedure for solving the numerical solutions is accelerated by the sparsity of Fourier operator under the space complexity of O(M3). Furthermore, the method makes it possible to solve the 3D Helmholtz equation with large grid number. The accuracy and efficiency of the method are validated by two test examples which have exact solutions.展开更多
In the enormous and still poorly mastered gap between the macro level, where well developed continuum theories of continuous media and engineering methods of calculation and design operate, and atomic, subordinate to ...In the enormous and still poorly mastered gap between the macro level, where well developed continuum theories of continuous media and engineering methods of calculation and design operate, and atomic, subordinate to the laws of quantum mechanics, there is an extensive meso-hierarchical level of the structure of matter. At this level unprecedented previously products and technologies can be artificially created. Nano technology is a qualitatively new strategy in technology: it creates objects in exactly the opposite way—large objects are created from small ones [1]. We have developed a new method for modeling acoustic monitoring of a layered-block elastic medium with several inclusions of various physical and mechanical hierarchical structures [2]. An iterative process is developed for solving the direct problem for the case of three hierarchical inclusions of l, m, s-th ranks based on the use of 2D integro-differential equations. The degree of hierarchy of inclusions is determined by the values of their ranks, which may be different, while the first rank is associated with the atomic structure, the following ranks are associated with increasing geometric sizes, which contain inclusions of lower ranks and sizes. Hierarchical inclusions are located in different layers one above the other: the upper one is abnormally plastic, the second is abnormally elastic and the third is abnormally dense. The degree of filling with inclusions of each rank for all three hierarchical inclusions is different. Modeling is carried out from smaller sizes to large inclusions;as a result, it becomes possible to determine the necessary parameters of the formed material from acoustic monitoring data.展开更多
Aim of this work was to present a study indicating the recognized system of values of nursing units in healthcare entities in Poland. Professionally active nurses (249) employed in medicinal entities were subjects in ...Aim of this work was to present a study indicating the recognized system of values of nursing units in healthcare entities in Poland. Professionally active nurses (249) employed in medicinal entities were subjects in the study. A random selection of individuals was applied in the study, and the participation in the research was declared by respondents consent to participate in it. A survey was used as the main form of measurement, and it was divided into direct and indirect survey. A standardized Rokeach’s scale of values [1] [2] consisting of two collections, each of which included 18 single values, was used. They were ranked by tested individuals according to the hierarchy of their values which allowed for recognizing which are the most important for them. Kruskal-Wallis’s test was applied in the study. Results: The social position is the most important value for nurses working in the district medical entities. For those working in the regional medical units, the most appreciated value is being ambitious, whereas in the clinical self-esteem. The socio-demographic data such as age, length of service, levels of education differentiate assessments of each recognized values in the group of nurses. The women between 31 and 40 consider being ambitious as the most important value, between 41 and 50 responsibility and between 20 and 30 self-esteem;responsibility is the most appreciated value for people with 21 - 25 years of experience because the older and more experienced the nurse is, the stronger her sense of responsibility becomes. A social position was appreciated the most by the nurses holding a nursing degree. Conclusions: There have been significant differences in terms of accepted values between nurses working in the district, provincial and clinical medical entities. Socio-demographic data such as age, length of service, education levels differentiate assessment of each recognized value in the group of nurses.展开更多
This paper focusses on the information asymmetry in crisis news after a serious incident in Tianjin, China, in 2015. The incident caused enormous damage and resulted in societal unrest because of the lack of reliable ...This paper focusses on the information asymmetry in crisis news after a serious incident in Tianjin, China, in 2015. The incident caused enormous damage and resulted in societal unrest because of the lack of reliable information from the formal media channels. Social media — micro blogs —played a major role in reporting on crisis situations. We divided netizens(i.e., the citizens of the net)into high and low types according to their information-critical level to the crisis news. The data shows information deterioration on the crisis news, related to the netizens’ information-critical level. For the traditional media there is the opportunity to use information quality distortion to make more marginal profits. This is possible only if the citizens’ information stays under a certain quality level. The result is overprovision of low quality news and high quality news driven out of the market, whereupon adverse selection(i.e., a lack of symmetric information) appears. However, by adopting a process view, we found self-correcting mechanism(i.e., dying out of rumors) of the social media communities in China.We provided a agent-base model and simulation to show that the more media exist in the market, the faster speed of the information deterioration, but also the capacity to ‘discuss’ rumors.展开更多
This study aims to examine the relationship between authentic leadership and employee proactive behavior. Based on self-determination theory, we argue that such a relationship is sequentially mediated by psychological...This study aims to examine the relationship between authentic leadership and employee proactive behavior. Based on self-determination theory, we argue that such a relationship is sequentially mediated by psychological empowerment and core self-evaluations. In addition, political skill plays a moderating role in the third stage. These hypotheses are validated by a sample of 65 leaders and 275 subordinates from two private enterprises in China's Mainland. Results show that authentic leadership Clime I） influences employees＇ proactive behavior Clime 3） through the psychological empowerment （Time I） and core self-evaluations of employees （Time 2）, and the relationship between core self-evaluations and proactive behavior is positively moderated by employees＇ political skill. In addition, bootstrapping results also verify the moderating role played by employees＇ political skill in the indirect relationship between authentic leadership and proactive behavior through core self-evaluations. Theoretical and managerial implications are further discussed in the light of these findings.展开更多
This paper investigates the relationship between employees＇ perception of work-family balance practices and work-family conflicts. It examines the role of challenge stress and hindrance stress as moderators. Based on...This paper investigates the relationship between employees＇ perception of work-family balance practices and work-family conflicts. It examines the role of challenge stress and hindrance stress as moderators. Based on survey data collected from 841 civil servants in Beijing, we found that perceived work-family balance practices may reduce work-family conflict, while challenge and hindrance work stresses were positively related to work-family conflict. In addition, challenge and hindrance stresses differentially moderated the relationship between perceived work-family practices and work-family conflict. When challenge stress is high then workffamily balance practices will reduce work-family conflict. However, under high hindrance stress, work-family balance practices will serve to reduce work-family conflict less. More detailed analysis of the configurational dimensions of work-family balance practices （work flexibility, and employee and family wellness care） are also tested. This study provides additional insight into the management of work-family interfaces and offers ideas for future research.展开更多
As leader creativity is found to be effective at promoting outcomes for organizations, more and more organizations select creative individuals as leaders. However, the influence of leader creativity has not received e...As leader creativity is found to be effective at promoting outcomes for organizations, more and more organizations select creative individuals as leaders. However, the influence of leader creativity has not received enough attention. Thus, this research seeks to focus on the potential influences of leader creativity in organizations. Based on social cognitive theory, we explore the relationship between leader creativity and subordinate organizational citizenship behavior （OCB）. We find that leader creativity is positively related to subordinate OCB, and perceived team creative efficacy mediates the relationship. Moreover, creative self-efficacy moderates the relationships between perceived team creative efficacy and subordinate OCB. We then discuss implications and limitations, and suggest directions for future research.展开更多
This paper highlights the internecine struggle within the top management team in listed companies in China. Drawing on a power perspective, we longitudinally examine the antecedents of CEO dismissal followed by inside...This paper highlights the internecine struggle within the top management team in listed companies in China. Drawing on a power perspective, we longitudinally examine the antecedents of CEO dismissal followed by inside succession in dual-path CEO career. It examines the influence of followers＇ power on the dismissal of incumbent CEO and demonstrates the liability of newness and outsiderness, which is strengthened by the power of followers. It also highlights conflicts of interest and team and the joint effects of followers＇ and outsiderness. competition within the top management power on both the liability of newness展开更多
Based on literature [J. Q. Li, Z. E. Ma and F. Q. Zhang, Stability analysis for an epidemic model with stage structure, J. Appl. Math. Comput. 9 （2008） 1672-1679], incorporating the recovery of the infected populati...Based on literature [J. Q. Li, Z. E. Ma and F. Q. Zhang, Stability analysis for an epidemic model with stage structure, J. Appl. Math. Comput. 9 （2008） 1672-1679], incorporating the recovery of the infected population with the length of the infectious periods, a modified epidemic disease SIS model with delay and stage was investigated. First, the criteria keeping stability with delay were given. Next, in order to lower the level of the infected individuals and minimize the cost of treatment, mixed, early and late therapeutic strategies were introduced into our model, respectively. Then we investigated the existence and uniqueness of optimal controls. And then, we expressed the unique optimal control in terms of the solution of the optimality systems. Finally, by numerical simulations, several important results were acquired： （1） The terminal time influenced the early optimal control largely. In detail, for a shorter terminal time it was optimal to initiate treatment with maximal effort at the start of the epidemic and continue treatment with maximal effort until the switch time was arrived. But for a longer terminal time, the maximal treatment effort need not be a prerequisite at the start or end of the epidemic but it was obligatory at the metaphase of the epidemic. （2） For our SIS model, minimizing the total infectious burden of the disease can be achieved by only early optimal treatment tactics. （3） For a disease with a shorter infectious period time,more cost would be spent to control the disease in order to achieve the optimal control objective. Otherwise, a relative lower cost would be to control the disease with a longer infectious period.展开更多
基金Supported by Ministry of Science and Higher Education Grant(WULS-SGGW:505-10-100400-L00332-99/2014)
文摘To analyse the association between isoflavone intake and ulcerative colitis motility symptoms in individuals in remission. METHODSCross-sectional study was conducted in a group of ulcerative colitis remission individuals, in sub-groups characterised by various intestinal motility and functioning characteristics (abdominal pain, flatulence, constipations, tenesmus). Total of 56 individuals with ulcerative colitis in remission (19 males and 37 females) were recruited for the study. Assessment of diet was based on self-reported data from each patient’s dietary records taken over a period of three typical, random days (2 weekdays and 1 d of the weekend). The daily isoflavone intake (daidzein, genistein, glycitein and total isoflavones) and daily isoflavone intake per 1000 kcal of diet were assessed. RESULTSNo correlations between isoflavone intake levels and number of bowel movements per day were observed both in the case of intake and intake per 1000 kcal of diet. In the group of individuals declaring lack of abdominal pain, the higher intakes of daidzein (P = 0.0075), daidzein per 1000 kcal of diet (P = 0.0358) and total isoflavone (P = 0.0358) were stated, than in the group of individuals declaring abdominal pain. In the group of individuals declaring lack of constipations, the lower intakes of glycitein (P = 0.0213) and glycitein per 1000 kcal of diet (P = 0.0213) were stated, than in the group of individuals declaring presence of constipations. No differences were observed in isoflavone intake between groups of ulcerative colitis individuals declaring lack of flatulence and declaring presence of flatulence, as well as between groups declaring lack of tenesmus and declaring presence of tenesmus. CONCLUSIONThe moderate dietary isoflavone intake may be beneficial for individuals with ulcerative colitis in remission, however, before including it into recommendations, further prospective studies are needed.
基金Supported by the National Natural Science Fund Project(31171657)Heilongjiang Province Natural Fund Project(ZD201207)Heilongjiang Province Postdoctoral Special Funds(LBH-Q13133)
文摘We cloned and expressed bile salt hydrolase gene ofLactobacillus plantarum M1-UVS29 in Lactococcus lactis NZ9000 successfully. Gene-specific primers for amplification of L. plantarum bsh were designed by using sequence which availabled from GenBank. The production of PCR amplicon was confirmed by sequencing and cloned into pMD18-T vector, and then recombined into expression vector pNZ8148 and yielding vector pNZ8148-BSH, pNZ8148-BSH was transferred into Lactococcus lactis NZ9000. Sequencing indicated that the cloned bsh fragment contained 995 nucleotides, and shared 99.3% sequence homology with bsh gene from L. plantarum MBUL10. Cloned bsh fragment was successfully transduced into NICE expression system and confirmed by PCR and restriction digest. Recombinant BSH protein was analyzed by SDS-PAGE. The molecular weight of BSH protein was approximately 37 ku. Activity of the expressed protein was 0.77 μmol· min^-1. The successfully expressed proteins by genetic engineering technology made the function of lactic acid bacteria be abundant and laid the foundation for further researches into cholesterol-lowering lactic acid bacterium food and probiotics.
文摘Radio Frequency IDentification(RFID)and related technologies such as Near Field Communication(NFC)are becoming essential in industrial contexts thanks to their ability to perform contactless data exchange,either device-to-device or tag-to-device.One of the three main operation modes of NFC,called read/write mode,makes use of the latter type of interaction.It is extensively used in business information systems that make use of NFC tags to provide the end-user with augmented information in one of several available NFC data exchange formats,such as plain text,simple URLs or enriched URLs.Using a wide variety of physical form factors,NFC-compatible tags(wireless transponders)are currently available in many locations with applications going from smart posters,contactless tokens,tap-and-go payments or transport ticketing to automated device configuration,patient identification at hospitals or inventory management within supply chains.Most of these applications handle sensitive processes or data.This paper proposes a complete security threat model for the read/write operation mode of NFC used in Next Generation Industrial IoT(Nx-IIoT)contexts.This model,based on a wellknown methodology,STRIDE,allows developers and users to identify NFC applications vulnerabilities or weaknesses,analyze potential threats,propose risk management strategies,and design mitigation mechanisms to mention only some significant examples.
文摘We present fast fourth-order finite difference scheme for 3D Helmholtz equation with Neumann boundary condition. We employ the discrete Fourier transform operator and divide the problem into some independent subproblems. By means of the Gaussian elimination in the vertical direction, the problem is reduced into a small system on the top layer of the domain. The procedure for solving the numerical solutions is accelerated by the sparsity of Fourier operator under the space complexity of O(M3). Furthermore, the method makes it possible to solve the 3D Helmholtz equation with large grid number. The accuracy and efficiency of the method are validated by two test examples which have exact solutions.
文摘In the enormous and still poorly mastered gap between the macro level, where well developed continuum theories of continuous media and engineering methods of calculation and design operate, and atomic, subordinate to the laws of quantum mechanics, there is an extensive meso-hierarchical level of the structure of matter. At this level unprecedented previously products and technologies can be artificially created. Nano technology is a qualitatively new strategy in technology: it creates objects in exactly the opposite way—large objects are created from small ones [1]. We have developed a new method for modeling acoustic monitoring of a layered-block elastic medium with several inclusions of various physical and mechanical hierarchical structures [2]. An iterative process is developed for solving the direct problem for the case of three hierarchical inclusions of l, m, s-th ranks based on the use of 2D integro-differential equations. The degree of hierarchy of inclusions is determined by the values of their ranks, which may be different, while the first rank is associated with the atomic structure, the following ranks are associated with increasing geometric sizes, which contain inclusions of lower ranks and sizes. Hierarchical inclusions are located in different layers one above the other: the upper one is abnormally plastic, the second is abnormally elastic and the third is abnormally dense. The degree of filling with inclusions of each rank for all three hierarchical inclusions is different. Modeling is carried out from smaller sizes to large inclusions;as a result, it becomes possible to determine the necessary parameters of the formed material from acoustic monitoring data.
文摘Aim of this work was to present a study indicating the recognized system of values of nursing units in healthcare entities in Poland. Professionally active nurses (249) employed in medicinal entities were subjects in the study. A random selection of individuals was applied in the study, and the participation in the research was declared by respondents consent to participate in it. A survey was used as the main form of measurement, and it was divided into direct and indirect survey. A standardized Rokeach’s scale of values [1] [2] consisting of two collections, each of which included 18 single values, was used. They were ranked by tested individuals according to the hierarchy of their values which allowed for recognizing which are the most important for them. Kruskal-Wallis’s test was applied in the study. Results: The social position is the most important value for nurses working in the district medical entities. For those working in the regional medical units, the most appreciated value is being ambitious, whereas in the clinical self-esteem. The socio-demographic data such as age, length of service, levels of education differentiate assessments of each recognized values in the group of nurses. The women between 31 and 40 consider being ambitious as the most important value, between 41 and 50 responsibility and between 20 and 30 self-esteem;responsibility is the most appreciated value for people with 21 - 25 years of experience because the older and more experienced the nurse is, the stronger her sense of responsibility becomes. A social position was appreciated the most by the nurses holding a nursing degree. Conclusions: There have been significant differences in terms of accepted values between nurses working in the district, provincial and clinical medical entities. Socio-demographic data such as age, length of service, education levels differentiate assessment of each recognized value in the group of nurses.
基金Supported by the National Natural Science Foundation of China(71503178)the National Social Science Fund of China(13ASH003)China Scholarship Council
文摘This paper focusses on the information asymmetry in crisis news after a serious incident in Tianjin, China, in 2015. The incident caused enormous damage and resulted in societal unrest because of the lack of reliable information from the formal media channels. Social media — micro blogs —played a major role in reporting on crisis situations. We divided netizens(i.e., the citizens of the net)into high and low types according to their information-critical level to the crisis news. The data shows information deterioration on the crisis news, related to the netizens’ information-critical level. For the traditional media there is the opportunity to use information quality distortion to make more marginal profits. This is possible only if the citizens’ information stays under a certain quality level. The result is overprovision of low quality news and high quality news driven out of the market, whereupon adverse selection(i.e., a lack of symmetric information) appears. However, by adopting a process view, we found self-correcting mechanism(i.e., dying out of rumors) of the social media communities in China.We provided a agent-base model and simulation to show that the more media exist in the market, the faster speed of the information deterioration, but also the capacity to ‘discuss’ rumors.
文摘This study aims to examine the relationship between authentic leadership and employee proactive behavior. Based on self-determination theory, we argue that such a relationship is sequentially mediated by psychological empowerment and core self-evaluations. In addition, political skill plays a moderating role in the third stage. These hypotheses are validated by a sample of 65 leaders and 275 subordinates from two private enterprises in China's Mainland. Results show that authentic leadership Clime I） influences employees＇ proactive behavior Clime 3） through the psychological empowerment （Time I） and core self-evaluations of employees （Time 2）, and the relationship between core self-evaluations and proactive behavior is positively moderated by employees＇ political skill. In addition, bootstrapping results also verify the moderating role played by employees＇ political skill in the indirect relationship between authentic leadership and proactive behavior through core self-evaluations. Theoretical and managerial implications are further discussed in the light of these findings.
基金This research was supported by the National Natural Science Foundation of China （Project no. 71372003）, and the Fundamental Research Funds for the Central Universities and the Research Funds of Renmin University of China （Grant no. 15XNL023）.
文摘This paper investigates the relationship between employees＇ perception of work-family balance practices and work-family conflicts. It examines the role of challenge stress and hindrance stress as moderators. Based on survey data collected from 841 civil servants in Beijing, we found that perceived work-family balance practices may reduce work-family conflict, while challenge and hindrance work stresses were positively related to work-family conflict. In addition, challenge and hindrance stresses differentially moderated the relationship between perceived work-family practices and work-family conflict. When challenge stress is high then workffamily balance practices will reduce work-family conflict. However, under high hindrance stress, work-family balance practices will serve to reduce work-family conflict less. More detailed analysis of the configurational dimensions of work-family balance practices （work flexibility, and employee and family wellness care） are also tested. This study provides additional insight into the management of work-family interfaces and offers ideas for future research.
文摘As leader creativity is found to be effective at promoting outcomes for organizations, more and more organizations select creative individuals as leaders. However, the influence of leader creativity has not received enough attention. Thus, this research seeks to focus on the potential influences of leader creativity in organizations. Based on social cognitive theory, we explore the relationship between leader creativity and subordinate organizational citizenship behavior （OCB）. We find that leader creativity is positively related to subordinate OCB, and perceived team creative efficacy mediates the relationship. Moreover, creative self-efficacy moderates the relationships between perceived team creative efficacy and subordinate OCB. We then discuss implications and limitations, and suggest directions for future research.
文摘This paper highlights the internecine struggle within the top management team in listed companies in China. Drawing on a power perspective, we longitudinally examine the antecedents of CEO dismissal followed by inside succession in dual-path CEO career. It examines the influence of followers＇ power on the dismissal of incumbent CEO and demonstrates the liability of newness and outsiderness, which is strengthened by the power of followers. It also highlights conflicts of interest and team and the joint effects of followers＇ and outsiderness. competition within the top management power on both the liability of newness
基金Acknowledgments The authors would like to thank the editor and the referee for constructive comments which significantly improves this paper. In addition, this work was supported by the National Natural Science Foundation of China （No. 11471243）.
文摘Based on literature [J. Q. Li, Z. E. Ma and F. Q. Zhang, Stability analysis for an epidemic model with stage structure, J. Appl. Math. Comput. 9 （2008） 1672-1679], incorporating the recovery of the infected population with the length of the infectious periods, a modified epidemic disease SIS model with delay and stage was investigated. First, the criteria keeping stability with delay were given. Next, in order to lower the level of the infected individuals and minimize the cost of treatment, mixed, early and late therapeutic strategies were introduced into our model, respectively. Then we investigated the existence and uniqueness of optimal controls. And then, we expressed the unique optimal control in terms of the solution of the optimality systems. Finally, by numerical simulations, several important results were acquired： （1） The terminal time influenced the early optimal control largely. In detail, for a shorter terminal time it was optimal to initiate treatment with maximal effort at the start of the epidemic and continue treatment with maximal effort until the switch time was arrived. But for a longer terminal time, the maximal treatment effort need not be a prerequisite at the start or end of the epidemic but it was obligatory at the metaphase of the epidemic. （2） For our SIS model, minimizing the total infectious burden of the disease can be achieved by only early optimal treatment tactics. （3） For a disease with a shorter infectious period time,more cost would be spent to control the disease in order to achieve the optimal control objective. Otherwise, a relative lower cost would be to control the disease with a longer infectious period.
