Mushrooms are experiencing a kind of renaissance as a part of the contemporary human diet.These valuable organisms are more than food,they fit in perfectly as a novel market group known as nutra-mycoceuticals.Immune-b...Mushrooms are experiencing a kind of renaissance as a part of the contemporary human diet.These valuable organisms are more than food,they fit in perfectly as a novel market group known as nutra-mycoceuticals.Immune-balancing mushroom dietary fibers and secondary metabolites such as polyphenols are the main focus of the healthcare industry.Wellness and cosmetic companies are increasingly using mushroom extracts rich in these ingredients.This review considers the basic molecular immunomodulatory mechanisms of action of the most commonly used mushroom dietary fibers,β-glucans.The literature data on their bioavailability,metabolic transformations,preclinical and human clinical research,and safety are discussed.Immunomodulatory mechanisms of polyphenol ingredients are also considered.These molecules present great potential in the design of the new immunity balancer formulations according to their widespread structural diversity.Finally,we draw attention to the perspectives of modern trends in mushroom nutraceutical and cosmeceutical formulations to strengthen and balance immunity.展开更多
The analysis of natural vibration characteristics has become one of important steps of the manufacture and dynamic design in the aerospace industry. This paper presents a new scenario called virtual cutting in the con...The analysis of natural vibration characteristics has become one of important steps of the manufacture and dynamic design in the aerospace industry. This paper presents a new scenario called virtual cutting in the context of the transfer matrix method of linear multibody systems closed- loop topology for computing the free vibration characteristics of elastically coupled flexible launch vehicle boosters. In this approach, the coupled system is idealized as a triple-beam system-like structure coupled by linear translational springs, where a non-uniform free-free Euler-Bemoulli beam is used. A large thrust-to-weight ratio leads to large axial accelera- tions that result in an axial inertia load distribution from nose to tail. Consequently, it causes the development of significant compressive forces along the length of the launch vehicle. Therefore, it is important to take into account this effect in the transverse vibration model. This scenario does not need the global dynamics equations of a system, and it has high computational efficiency and low memory requirements. The validity of the presented scenario is achieved through com- parison to other approaches published in the literature.展开更多
Recently, due to the growth of environmental pollution and the increase in the resistance of microorganisms to artificially create chemical drugs, there has been an urgent need for a radical change in the direction of...Recently, due to the growth of environmental pollution and the increase in the resistance of microorganisms to artificially create chemical drugs, there has been an urgent need for a radical change in the direction of the medical preparations development, for changing chemicals to naturally produced ones based on herbal natural remedies. Since homeopathy is a branch of medicine that includes not only herbal preparations, but also chemical ingredients, our newly developed patent—although it belongs to the field of homeopathy—is its offshoot aimed solely at maintaining the body’s strength without harming it, increasing the survival of the body in a polluted environment removing toxins from the body by strengthening adaptive immune mechanisms. Thus, thyme, cumin, oregano, licorice, and other natural resources of the earth, which are the basis of our patent, successfully fight cold and diseases of the upper respiratory tract. The article presents a methodology for the development of a new herbal preparation, its dosage, and use as the main ingredient in a treatment course in infectious diseases.展开更多
Objective:To elucidate the relationship among knowledge,attitudes,and practices regarding Covid-19 and their relationship with booster vaccination status among women with infertility.Methods:This questionnaire-based c...Objective:To elucidate the relationship among knowledge,attitudes,and practices regarding Covid-19 and their relationship with booster vaccination status among women with infertility.Methods:This questionnaire-based cross-sectional study was performed online and offline among women with infertility who visited an infertility clinic in Jakarta,Indonesia.We assessed the patient’s knowledge,attitudes,and practices regarding Covid-19 and their relationship with booster vaccination status and sociodemographic profile.Results:A total of 178 subjects participated in this study,and most participants(92.6%)had received booster Covid-19 vaccines.From the questionnaire,74.2%had good knowledge,and 99.4%had good attitudes regarding Covid-19;however,only 57.9%of patients had good practices.A weak positive correlation existed between knowledge and attitudes(r=0.11,P=0.13)and a moderate negative correlation between attitudes and practices(r=-0.44,P=0.56).Participants’knowledge about vaccines and infertility was correlated with booster vaccination status(P=0.04).Academic background(P=0.01)and attitudes(P=0.01)were also correlated with booster vaccination status.The significant determinants of hesitance of receiving Covid-19 booster vaccines were high school education or below(OR=0.08,95%CI 0.02-0.36)and poor practices(OR=0.21,95%CI 0.05-0.95).Conclusions:The majority of the participants had received the Covid-19 booster vaccine and had good knowledge and attitudes but poor practices regarding Covid-19.Most participants had poor knowledge about the relationship between infertility and the Covid-19 vaccine.The general population should be more informed and reminded about practices to prevent Covid-19 and the relationship between vaccination and fertility to increase the number of people who receive Covid-19 booster vaccines.展开更多
The high-energy photon source(HEPS)is the first fourth-generation synchrotron light source facility in China.The HEPS injector consists of a linear accelerator(Linac)and a full energy booster.The booster captures the ...The high-energy photon source(HEPS)is the first fourth-generation synchrotron light source facility in China.The HEPS injector consists of a linear accelerator(Linac)and a full energy booster.The booster captures the electron beam from the Linac and increases its energy to the value required for the storage ring.The full-energy beam could be injected to the storage ring directly or after“high-energy accumulation.”On November 17,2023,the key booster parameters successfully reached their corresponding target values.These milestone results were achieved based on numerous contributions,including nearly a decade of physical design,years of equipment development and installation,and months of beam commissioning.As measured at the extraction energy of 6 GeV,the averaged beam current and emittance reached 8.57 mA with 5 bunches and 30.37 nm rad with a single-bunch charge of 5.58 nC,compared with the corresponding target values of 6.6 mA and 35 nm rad,respectively.This paper presents the physical design,equipment development,installation,and commissioning process of the HEPS booster.展开更多
For people living in Yantai, a coastal city in Shandong Province in east China, catching an international flight to the Republic of Korea (ROK) takes just about an hour due to the short distance. That is one of the re...For people living in Yantai, a coastal city in Shandong Province in east China, catching an international flight to the Republic of Korea (ROK) takes just about an hour due to the short distance. That is one of the reasons Yantai was chosen to build the China-ROK Industrial Park in 1984, attracting major ROK enterprises such as electronic giant LG and construction machinery maker Doosan Group.展开更多
The role of the rocket attitude control system is to execute the required maneuvers for guidance and ensure the stability of the rocket's flight attitude. Attitude control technology has always been one of the key...The role of the rocket attitude control system is to execute the required maneuvers for guidance and ensure the stability of the rocket's flight attitude. Attitude control technology has always been one of the key technologies for ensuring the success of rocket flights and has been a core topic in carrier rocket technology research. The Gravity-1 solid carrier rocket is the first solid rocket bundled rocket developed by China, adopting a configuration with four boosters and a core stage bundled together. During the actual flight process, the four booster engines are ignited first, and then, in the event of insufficient control force from the boosters, the core stage engine is ignited to participate in control. To address thrust asynchrony during the descent of the four boosters, an Extended State Observer(ESO) is employed in the control scheme for this flight segment. This involves real-time estimation and compensation of attitude parameters during flight, identification of thrust asynchrony among the boosters, and simultaneous determination of whether the core stage engine is ignited to participate in control.Through six degrees of freedom simulation analysis and Y1 flight test validation, this method has been proven to be correct and feasible.展开更多
Deputy Governor of the central bank, Wu Xiaoling, highlights the pivotal role that private equity plays in boosting China’s economy At the 2007 China M&A Annual Conference in Tianjin, Wu Xiaoling, Deputy Governor of
Objective:To examine the pattern of COVID-19 infection and vaccination,and to explore pregnant women’s willingness and reluctance to accept a booster dose of the COVID-19 vaccine.Methods:This was a cross-sectional,de...Objective:To examine the pattern of COVID-19 infection and vaccination,and to explore pregnant women’s willingness and reluctance to accept a booster dose of the COVID-19 vaccine.Methods:This was a cross-sectional,descriptive study with a convenient sample size using a structured questionnaire among pregnant women attending the gynecology and obstetrics department at Acıbadem Mehmet Ali Aydinlar Hospital,Istanbul,Türkiye.The Health Belief Model scale was used to assess the intention and reluctance to accept a booster dose of the COVID-19 vaccine.Results:A total of 145 participants,with a mean age of(33.5±4.8)years,and a gestational age of(30.9±7.3)weeks,were enrolled in this study.88.8%Received full doses of the Pfizer-BioNTech vaccination.47.8%Participants suffered from vaccine adverse effects.Health Belief Model demonstrated a significant finding of perceived susceptibility(P<0.001),perceived severity of COVID-19 complications(P<0.001),and perceived benefits regarding a booster COVID-19 vaccination(P<0.001).Conclusions:Most pregnant women who received the COVID-19 immunization express a significant intention to receive a booster dose,regardless of the adverse effects experienced from the previous doses.However,a small percentage of the study sample express hesitancy about receiving the booster dose.展开更多
Background:We analysed data garnered during the ongoing Italian nationwide coronavirus disease 2019(COVID-19)vaccination campaign for comparing early COVID-19 monovalent vaccine efficacy in older persons who received ...Background:We analysed data garnered during the ongoing Italian nationwide coronavirus disease 2019(COVID-19)vaccination campaign for comparing early COVID-19 monovalent vaccine efficacy in older persons who received the primary vaccination cycle,the first vaccine booster,and the second vaccine booster.Methods:We conducted a retrospective analysis of early COVID-19 monovalent vaccine efficacy(i.e.,within 120 days)against COVID-19 related hospitalizations,intensive care unit(ICU)admissions and deaths in older persons(i.e.,aged≥80 years),by accessing official data of the COVID-19 national integrated surveillance program instituted by the Italian National Institute of Health.Vaccine efficacy was compared(odds ratio;OR)among cohorts receiving the primary vaccination cycle,the first vaccine booster,and the second vaccine booster.Results:A consistent decline could be seen in the rate of COVID-19 hospitalizations,ICU admissions and deaths with increasing number of monovalent immunizations.Within 120 days of administration,the first and second vaccine boosters had superior efficacy compared to the primary vaccination cycle,reducing the odds of all endpoints between 62%-71%and 69%-84%,respectively.A modestly superior early efficacy could also be noted for the second versus the first monovalent vaccine booster(ORs of all endpoints further reduced by 18%-48%).Conclusion:Since an increasing number of immunizations is associated with a lower risk of unfavourable COVID-19 outcomes,vaccine boosters may be useful for limiting the clinical burden of this infectious disease in elderly populations.展开更多
Objective:Since the opportunity of widespread administration of the fourth mRNA-based coronavirus disease 2019(COVID-19)vaccine dose remains controversial,this article provides a pooled analysis of the efficacy of the...Objective:Since the opportunity of widespread administration of the fourth mRNA-based coronavirus disease 2019(COVID-19)vaccine dose remains controversial,this article provides a pooled analysis of the efficacy of the second COVID-19 mRNA-based homologous vaccine booster in eliciting anti-SARS-CoV-2 serum antibody response in general immunocompetent populations.Methods:We conducted a digital search in Medline using the keywords"fourth dose"or"second booster"and"antibodies"and"COVID-19"or"SARS-CoV-2"and"BNT162b2"or"mRNA-1273",to identify all clinical studies which evaluated the anti-SARS-CoV-2 serum antibody response after the fourth mRNA-based COVID-19 homologous vaccine dose administration in general immunocompetent populations compared to the response seen before its administration and after the first booster.Results:Four studies totaling 571 recipients of the second mRNA-based COVID-19 vaccine booster were finally included in our analysis.The weighted mean difference(WMD)ratio of anti-SARS-CoV-2 serum antibodies levels measured after and before administration of the fourth vaccine dose was 9.7(95%CI,6.5-12.9)in those receiving BNT162b2 and 12.0(95%CI,5.8-18.2)in those receiving mRNA-1273,respectively.The WMD ratio of anti-SARS-CoV-2 serum antibodies levels measured at the peak of the fourth and third vaccine doses was 1.4(95%CI,1.2-1.7)in those receiving BNT162b2 and 1.9(95%CI,1.5-2.4)in those receiving mRNA-1273,respectively.Conclusion:Our data confirm the efficacy of the fourth mRNA-based COVID-19 vaccine dose in restoring a satisfactory level of anti-SARS-CoV-2 serum antibodies,though such effectiveness seems only marginally superior to that of the first booster.展开更多
The LM-5B launch vehicle is a new-generation large launch vehicle specially developed for the construction of China’s space station under its manned space program,and it has the largest launching capacity to low Eart...The LM-5B launch vehicle is a new-generation large launch vehicle specially developed for the construction of China’s space station under its manned space program,and it has the largest launching capacity to low Earth orbit in China.The LM-5B booster is the largest booster ever built in China,which can produce 90%of the total thrust at liftoff,which laid a solid foundation for the successful development of the LM-5B launch vehicle.The booster team has overcome many technical challenges and gained rich experience in developing large cryogenic launch vehicles.展开更多
Since a thrust of an ion rocket engine is much weaker than the one of a chemical fuel engine, nowadays, ion engines are used mainly in spaces where gravities are very weak. Here, as a powerful plasma rocket to make a ...Since a thrust of an ion rocket engine is much weaker than the one of a chemical fuel engine, nowadays, ion engines are used mainly in spaces where gravities are very weak. Here, as a powerful plasma rocket to make a heavy ship get out from the gravity-sphere of the earth without relying on an atomic power rocket, an ion-velocity booster is investigated. It is a main challenge how to protect the engine wall from the melting due to collisions of ions which grow into high-energy particles.展开更多
A hybrid rocket motor combines components from both solid fuel and liquid fuel rocket motors. The fuel itself is a solid grain, (often paraffin or hydroxyl-terminated polybutadiene, known as HTPB) while the oxidizing ...A hybrid rocket motor combines components from both solid fuel and liquid fuel rocket motors. The fuel itself is a solid grain, (often paraffin or hydroxyl-terminated polybutadiene, known as HTPB) while the oxidizing agent is liquid (often hydrogen peroxide or liquid oxygen). These components are combined in the fuel chamber which doubles as the combustion chamber for the hybrid motor. This review looks at the advances in techniques that have taken place in the development of these motors since 1995. Methods of testing the thrust from rocket motors and of measuring the rocket plume spectroscopically for combustion reaction products have been developed. These assessments allow researchers to more completely understand the effects of additives and physical changes in design, in terms of regression rates and thrust developed. Hybrid rocket motors have been used or tested in many areas of rocketry, including tactical rockets and large launch vehicles. Several additives have shown significant improvements in regression rates and thrust, including Guanidinium azotetrazolate (GAT), and various Aluminum alloys. The most recent discoveries have come from research into nano-particle additives. The nano-particles have been shown to provide enhancements to many parameters of hybrid rocket function, and research into specific areas continues in the sub-field of nano-additives for fuel grains.展开更多
Studies based on AC high voltage tests have been done at Cepel to investigate the performance of 800 kV busbar insulators under heavy wetting conditions.Insulators were tested which are now used on site and also with ...Studies based on AC high voltage tests have been done at Cepel to investigate the performance of 800 kV busbar insulators under heavy wetting conditions.Insulators were tested which are now used on site and also with different configurations of booster sheds.Images recorded by ultra-violet(UV) camera were used to help the investigations on the effectiveness of booster sheds.By comparing UV images of the insulator being stressed with high voltage under heavy artificial rain,with and without booster sheds,it was possible to observe how significant the reduction on the flashover formation process was when booster sheds were used.The effectiveness of booster sheds was also quantified by determining the disruptive discharge of the insulator with and without them.The results of these studies can also be considered as contribution to national and international standard technical committees to improving the standardized procedure for tests on ultra high voltage(UHV) insulators under heavy rain.Subjects such as the clear definition of relevant UHV test procedure and test arrangements,including the use of UV camera,have to be taken into account.展开更多
基金supported by the Science Fund of the Republic of Serbia,#Grant No:7748088。
文摘Mushrooms are experiencing a kind of renaissance as a part of the contemporary human diet.These valuable organisms are more than food,they fit in perfectly as a novel market group known as nutra-mycoceuticals.Immune-balancing mushroom dietary fibers and secondary metabolites such as polyphenols are the main focus of the healthcare industry.Wellness and cosmetic companies are increasingly using mushroom extracts rich in these ingredients.This review considers the basic molecular immunomodulatory mechanisms of action of the most commonly used mushroom dietary fibers,β-glucans.The literature data on their bioavailability,metabolic transformations,preclinical and human clinical research,and safety are discussed.Immunomodulatory mechanisms of polyphenol ingredients are also considered.These molecules present great potential in the design of the new immunity balancer formulations according to their widespread structural diversity.Finally,we draw attention to the perspectives of modern trends in mushroom nutraceutical and cosmeceutical formulations to strengthen and balance immunity.
基金supported by the Research Fund for the Doctoral Program of Higher Education of China(Grants 20113219110025,20133219110037)the National Natural Science Foundation of China(Grants 11102089,61304137)the Program for New Century Excellent Talents in University(NCET-10-0075)
文摘The analysis of natural vibration characteristics has become one of important steps of the manufacture and dynamic design in the aerospace industry. This paper presents a new scenario called virtual cutting in the context of the transfer matrix method of linear multibody systems closed- loop topology for computing the free vibration characteristics of elastically coupled flexible launch vehicle boosters. In this approach, the coupled system is idealized as a triple-beam system-like structure coupled by linear translational springs, where a non-uniform free-free Euler-Bemoulli beam is used. A large thrust-to-weight ratio leads to large axial accelera- tions that result in an axial inertia load distribution from nose to tail. Consequently, it causes the development of significant compressive forces along the length of the launch vehicle. Therefore, it is important to take into account this effect in the transverse vibration model. This scenario does not need the global dynamics equations of a system, and it has high computational efficiency and low memory requirements. The validity of the presented scenario is achieved through com- parison to other approaches published in the literature.
文摘Recently, due to the growth of environmental pollution and the increase in the resistance of microorganisms to artificially create chemical drugs, there has been an urgent need for a radical change in the direction of the medical preparations development, for changing chemicals to naturally produced ones based on herbal natural remedies. Since homeopathy is a branch of medicine that includes not only herbal preparations, but also chemical ingredients, our newly developed patent—although it belongs to the field of homeopathy—is its offshoot aimed solely at maintaining the body’s strength without harming it, increasing the survival of the body in a polluted environment removing toxins from the body by strengthening adaptive immune mechanisms. Thus, thyme, cumin, oregano, licorice, and other natural resources of the earth, which are the basis of our patent, successfully fight cold and diseases of the upper respiratory tract. The article presents a methodology for the development of a new herbal preparation, its dosage, and use as the main ingredient in a treatment course in infectious diseases.
文摘Objective:To elucidate the relationship among knowledge,attitudes,and practices regarding Covid-19 and their relationship with booster vaccination status among women with infertility.Methods:This questionnaire-based cross-sectional study was performed online and offline among women with infertility who visited an infertility clinic in Jakarta,Indonesia.We assessed the patient’s knowledge,attitudes,and practices regarding Covid-19 and their relationship with booster vaccination status and sociodemographic profile.Results:A total of 178 subjects participated in this study,and most participants(92.6%)had received booster Covid-19 vaccines.From the questionnaire,74.2%had good knowledge,and 99.4%had good attitudes regarding Covid-19;however,only 57.9%of patients had good practices.A weak positive correlation existed between knowledge and attitudes(r=0.11,P=0.13)and a moderate negative correlation between attitudes and practices(r=-0.44,P=0.56).Participants’knowledge about vaccines and infertility was correlated with booster vaccination status(P=0.04).Academic background(P=0.01)and attitudes(P=0.01)were also correlated with booster vaccination status.The significant determinants of hesitance of receiving Covid-19 booster vaccines were high school education or below(OR=0.08,95%CI 0.02-0.36)and poor practices(OR=0.21,95%CI 0.05-0.95).Conclusions:The majority of the participants had received the Covid-19 booster vaccine and had good knowledge and attitudes but poor practices regarding Covid-19.Most participants had poor knowledge about the relationship between infertility and the Covid-19 vaccine.The general population should be more informed and reminded about practices to prevent Covid-19 and the relationship between vaccination and fertility to increase the number of people who receive Covid-19 booster vaccines.
基金This work was supported by the National Natural Science Foundation of China(No.12005239).
文摘The high-energy photon source(HEPS)is the first fourth-generation synchrotron light source facility in China.The HEPS injector consists of a linear accelerator(Linac)and a full energy booster.The booster captures the electron beam from the Linac and increases its energy to the value required for the storage ring.The full-energy beam could be injected to the storage ring directly or after“high-energy accumulation.”On November 17,2023,the key booster parameters successfully reached their corresponding target values.These milestone results were achieved based on numerous contributions,including nearly a decade of physical design,years of equipment development and installation,and months of beam commissioning.As measured at the extraction energy of 6 GeV,the averaged beam current and emittance reached 8.57 mA with 5 bunches and 30.37 nm rad with a single-bunch charge of 5.58 nC,compared with the corresponding target values of 6.6 mA and 35 nm rad,respectively.This paper presents the physical design,equipment development,installation,and commissioning process of the HEPS booster.
文摘For people living in Yantai, a coastal city in Shandong Province in east China, catching an international flight to the Republic of Korea (ROK) takes just about an hour due to the short distance. That is one of the reasons Yantai was chosen to build the China-ROK Industrial Park in 1984, attracting major ROK enterprises such as electronic giant LG and construction machinery maker Doosan Group.
文摘The role of the rocket attitude control system is to execute the required maneuvers for guidance and ensure the stability of the rocket's flight attitude. Attitude control technology has always been one of the key technologies for ensuring the success of rocket flights and has been a core topic in carrier rocket technology research. The Gravity-1 solid carrier rocket is the first solid rocket bundled rocket developed by China, adopting a configuration with four boosters and a core stage bundled together. During the actual flight process, the four booster engines are ignited first, and then, in the event of insufficient control force from the boosters, the core stage engine is ignited to participate in control. To address thrust asynchrony during the descent of the four boosters, an Extended State Observer(ESO) is employed in the control scheme for this flight segment. This involves real-time estimation and compensation of attitude parameters during flight, identification of thrust asynchrony among the boosters, and simultaneous determination of whether the core stage engine is ignited to participate in control.Through six degrees of freedom simulation analysis and Y1 flight test validation, this method has been proven to be correct and feasible.
文摘Deputy Governor of the central bank, Wu Xiaoling, highlights the pivotal role that private equity plays in boosting China’s economy At the 2007 China M&A Annual Conference in Tianjin, Wu Xiaoling, Deputy Governor of
文摘Objective:To examine the pattern of COVID-19 infection and vaccination,and to explore pregnant women’s willingness and reluctance to accept a booster dose of the COVID-19 vaccine.Methods:This was a cross-sectional,descriptive study with a convenient sample size using a structured questionnaire among pregnant women attending the gynecology and obstetrics department at Acıbadem Mehmet Ali Aydinlar Hospital,Istanbul,Türkiye.The Health Belief Model scale was used to assess the intention and reluctance to accept a booster dose of the COVID-19 vaccine.Results:A total of 145 participants,with a mean age of(33.5±4.8)years,and a gestational age of(30.9±7.3)weeks,were enrolled in this study.88.8%Received full doses of the Pfizer-BioNTech vaccination.47.8%Participants suffered from vaccine adverse effects.Health Belief Model demonstrated a significant finding of perceived susceptibility(P<0.001),perceived severity of COVID-19 complications(P<0.001),and perceived benefits regarding a booster COVID-19 vaccination(P<0.001).Conclusions:Most pregnant women who received the COVID-19 immunization express a significant intention to receive a booster dose,regardless of the adverse effects experienced from the previous doses.However,a small percentage of the study sample express hesitancy about receiving the booster dose.
文摘Background:We analysed data garnered during the ongoing Italian nationwide coronavirus disease 2019(COVID-19)vaccination campaign for comparing early COVID-19 monovalent vaccine efficacy in older persons who received the primary vaccination cycle,the first vaccine booster,and the second vaccine booster.Methods:We conducted a retrospective analysis of early COVID-19 monovalent vaccine efficacy(i.e.,within 120 days)against COVID-19 related hospitalizations,intensive care unit(ICU)admissions and deaths in older persons(i.e.,aged≥80 years),by accessing official data of the COVID-19 national integrated surveillance program instituted by the Italian National Institute of Health.Vaccine efficacy was compared(odds ratio;OR)among cohorts receiving the primary vaccination cycle,the first vaccine booster,and the second vaccine booster.Results:A consistent decline could be seen in the rate of COVID-19 hospitalizations,ICU admissions and deaths with increasing number of monovalent immunizations.Within 120 days of administration,the first and second vaccine boosters had superior efficacy compared to the primary vaccination cycle,reducing the odds of all endpoints between 62%-71%and 69%-84%,respectively.A modestly superior early efficacy could also be noted for the second versus the first monovalent vaccine booster(ORs of all endpoints further reduced by 18%-48%).Conclusion:Since an increasing number of immunizations is associated with a lower risk of unfavourable COVID-19 outcomes,vaccine boosters may be useful for limiting the clinical burden of this infectious disease in elderly populations.
文摘Objective:Since the opportunity of widespread administration of the fourth mRNA-based coronavirus disease 2019(COVID-19)vaccine dose remains controversial,this article provides a pooled analysis of the efficacy of the second COVID-19 mRNA-based homologous vaccine booster in eliciting anti-SARS-CoV-2 serum antibody response in general immunocompetent populations.Methods:We conducted a digital search in Medline using the keywords"fourth dose"or"second booster"and"antibodies"and"COVID-19"or"SARS-CoV-2"and"BNT162b2"or"mRNA-1273",to identify all clinical studies which evaluated the anti-SARS-CoV-2 serum antibody response after the fourth mRNA-based COVID-19 homologous vaccine dose administration in general immunocompetent populations compared to the response seen before its administration and after the first booster.Results:Four studies totaling 571 recipients of the second mRNA-based COVID-19 vaccine booster were finally included in our analysis.The weighted mean difference(WMD)ratio of anti-SARS-CoV-2 serum antibodies levels measured after and before administration of the fourth vaccine dose was 9.7(95%CI,6.5-12.9)in those receiving BNT162b2 and 12.0(95%CI,5.8-18.2)in those receiving mRNA-1273,respectively.The WMD ratio of anti-SARS-CoV-2 serum antibodies levels measured at the peak of the fourth and third vaccine doses was 1.4(95%CI,1.2-1.7)in those receiving BNT162b2 and 1.9(95%CI,1.5-2.4)in those receiving mRNA-1273,respectively.Conclusion:Our data confirm the efficacy of the fourth mRNA-based COVID-19 vaccine dose in restoring a satisfactory level of anti-SARS-CoV-2 serum antibodies,though such effectiveness seems only marginally superior to that of the first booster.
文摘The LM-5B launch vehicle is a new-generation large launch vehicle specially developed for the construction of China’s space station under its manned space program,and it has the largest launching capacity to low Earth orbit in China.The LM-5B booster is the largest booster ever built in China,which can produce 90%of the total thrust at liftoff,which laid a solid foundation for the successful development of the LM-5B launch vehicle.The booster team has overcome many technical challenges and gained rich experience in developing large cryogenic launch vehicles.
文摘Since a thrust of an ion rocket engine is much weaker than the one of a chemical fuel engine, nowadays, ion engines are used mainly in spaces where gravities are very weak. Here, as a powerful plasma rocket to make a heavy ship get out from the gravity-sphere of the earth without relying on an atomic power rocket, an ion-velocity booster is investigated. It is a main challenge how to protect the engine wall from the melting due to collisions of ions which grow into high-energy particles.
文摘A hybrid rocket motor combines components from both solid fuel and liquid fuel rocket motors. The fuel itself is a solid grain, (often paraffin or hydroxyl-terminated polybutadiene, known as HTPB) while the oxidizing agent is liquid (often hydrogen peroxide or liquid oxygen). These components are combined in the fuel chamber which doubles as the combustion chamber for the hybrid motor. This review looks at the advances in techniques that have taken place in the development of these motors since 1995. Methods of testing the thrust from rocket motors and of measuring the rocket plume spectroscopically for combustion reaction products have been developed. These assessments allow researchers to more completely understand the effects of additives and physical changes in design, in terms of regression rates and thrust developed. Hybrid rocket motors have been used or tested in many areas of rocketry, including tactical rockets and large launch vehicles. Several additives have shown significant improvements in regression rates and thrust, including Guanidinium azotetrazolate (GAT), and various Aluminum alloys. The most recent discoveries have come from research into nano-particle additives. The nano-particles have been shown to provide enhancements to many parameters of hybrid rocket function, and research into specific areas continues in the sub-field of nano-additives for fuel grains.
文摘Studies based on AC high voltage tests have been done at Cepel to investigate the performance of 800 kV busbar insulators under heavy wetting conditions.Insulators were tested which are now used on site and also with different configurations of booster sheds.Images recorded by ultra-violet(UV) camera were used to help the investigations on the effectiveness of booster sheds.By comparing UV images of the insulator being stressed with high voltage under heavy artificial rain,with and without booster sheds,it was possible to observe how significant the reduction on the flashover formation process was when booster sheds were used.The effectiveness of booster sheds was also quantified by determining the disruptive discharge of the insulator with and without them.The results of these studies can also be considered as contribution to national and international standard technical committees to improving the standardized procedure for tests on ultra high voltage(UHV) insulators under heavy rain.Subjects such as the clear definition of relevant UHV test procedure and test arrangements,including the use of UV camera,have to be taken into account.