The combination of flow elasticity and inertia has emerged as a viable tool for focusing and manipulating particles using microfluidics.Although there is considerable interest in the field of elasto-inertial microflui...The combination of flow elasticity and inertia has emerged as a viable tool for focusing and manipulating particles using microfluidics.Although there is considerable interest in the field of elasto-inertial microfluidics owing to its potential applications,research on particle focusing has been mostly limited to low Reynolds numbers(Re<1),and particle migration toward equilibrium positions has not been extensively examined.In this work,we thoroughly studied particle focusing on the dynamic range of flow rates and particle migration using straight microchannels with a single inlet high aspect ratio.We initially explored several parameters that had an impact on particle focusing,such as the particle size,channel dimensions,concentration of viscoelastic fluid,and flow rate.Our experimental work covered a wide range of dimensionless numbers(0.05<Reynolds number<85,1.5<Weissenberg number<3800,5<Elasticity number<470)using 3,5,7,and 10μm particles.Our results showed that the particle size played a dominant role,and by tuning the parameters,particle focusing could be achieved at Reynolds numbers ranging from 0.2(1μL/min)to 85(250μL/min).Furthermore,we numerically and experimentally studied particle migration and reported differential particle migration for high-resolution separations of 5μm,7μm and 10μm particles in a sheathless flow at a throughput of 150μL/min.Our work elucidates the complex particle transport in elasto-inertial flows and has great potential for the development of high-throughput and high-resolution particle separation for biomedical and environmental applications.展开更多
Interposers with through-silicon vias(TSVs)play a key role in the three-dimensional integration and packaging of integrated circuits and microelectromechanical systems.In the current practice of fabricating interposer...Interposers with through-silicon vias(TSVs)play a key role in the three-dimensional integration and packaging of integrated circuits and microelectromechanical systems.In the current practice of fabricating interposers,solder balls are placed next to the vias;however,this approach requires a large foot print for the input/output(I/O)connections.Therefore,in this study,we investigate the possibility of placing the solder balls directly on top of the vias,thereby enabling a smaller pitch between the solder balls and an increased density of the I/O connections.To reach this goal,inkjet printing(that is,piezo and super inkjet)was used to successfully fill and planarize hollow metal TSVs with a dielectric polymer.The under bump metallization(UBM)pads were also successfully printed with inkjet technology on top of the polymer-filled vias,using either Ag or Au inks.The reliability of the TSV interposers was investigated by a temperature cycling stress test(−40℃ to+125℃).The stress test showed no impact on DC resistance of the TSVs;however,shrinkage and delamination of the polymer was observed,along with some micro-cracks in the UBM pads.For proof of concept,SnAgCu-based solder balls were jetted on the UBM pads.展开更多
Water and energy are inextricably linked, and as a consequence both have to be addressed together. This is called the water-energy nexus. When access to either is limited, it becomes obvious that it is necessary to co...Water and energy are inextricably linked, and as a consequence both have to be addressed together. This is called the water-energy nexus. When access to either is limited, it becomes obvious that it is necessary to consider their interdependence. Population growth, climate change, urbanization, increasing living standards and food con- sumption will require an integrated approach where food, water and energy security are considered together. In this paper we examine water, energy and food security and their couplings. The nexus also creates conflicts between water use, energy extraction and generation as well as food production. Some of these conflicts are illustrated. It is argued that there is an urgent need for integrated planning and operation. Not only will better technology be needed, but also better integration of policies, organizations and political decisions.展开更多
The prediction of the influent load is of great importance for the improvement of the control system to a large wastewater treatment plant. A systematic data analysis method is presented in this paper in order to esti...The prediction of the influent load is of great importance for the improvement of the control system to a large wastewater treatment plant. A systematic data analysis method is presented in this paper in order to estimate and predict the periodicity of the influent flow rate and ammonia （NH3） concentrations： 1） data filtering using wavelet decomposition and reconstruction; 2） typical cycle identification using power spectrum density analysis; 3） fitting and prediction model establishment based on an autoregressive model. To give meaningful information for feedforward control systems, predictions in different time scales are tested to compare the corresponding predicting accuracy. Considering the influence of the rainfalls, a linear fitting model is derived to estimate the relationship between flow rate trend and rain events. Measurements used to support coefficient fitting and model testing are acquired from two municipal wastewater treatment plants in China. The results show that 1） for both of the two plants, the periodicity affects the flow rate and NH3 concentrations in different cycles （especially cycles longer than 1 day）; 2） when the flow rate and NH3 concentrations present an obvious periodicity, the decreasing of prediction accuracy is not distinct with increasing of the prediction time scales; 3） the periodicity influence is larger than rainfalls; 4） the rainfalls will make the periodicity of flow rate less obvious in intensive rainy periods.展开更多
Full-scale experiments have been carried out to adapt the activated sludge model ASM2d to include the influence of metal dosage （Fe^3＋ and Al^3＋） for phosphorus removal. Phosphorus removal rates, nitrification rat...Full-scale experiments have been carried out to adapt the activated sludge model ASM2d to include the influence of metal dosage （Fe^3＋ and Al^3＋） for phosphorus removal. Phosphorus removal rates, nitrification rates, as well as pH and sludge settling performance, were evaluated as functions of the metal dosages. Furthermore, models relating certain parameters to the dosage of chemicals have been derived. Corresponding parameters in the ASM2d and the secondary settler models, included in the Benchmark Simulation Model No 1 （BSM1）, have been modified to take the metal influence into consideration. Based on the effluent limits and penalty policy of China, an equivalent evaluation method was derived for the total cost assessment. A large number of 300-day steady-state and 14-day open-loop dynamic simulations were performed to demonstrate the difference in behavior between the original and the modified BSM1. The results show that 1） both in low and high mole concentrations, Fe^3＋ addition results in a higher phosphorus removal rate than Al^3＋; 2） the sludge settling velocity will increase due to the metal addition; 3） the respiration rate of the activated sludge is decreased more by the dosage of Al^3＋ than Fe^3＋; 4） the inhibition of Al^3＋ on the nitrification rate is stronger than that of Fe^3＋; 5） the total operating cost will reach the minimum point for smaller dosages of Fe^3＋, but always increase with Al^3＋ addition.展开更多
Grey-sided voles(Myodes rufocanus)and bank voles(Myodes glareolus)co-exist in boreal forests in northern Scandinavia.Previous studies suggest that the 2 species interact interspecifically,the grey-sided vole be&...Grey-sided voles(Myodes rufocanus)and bank voles(Myodes glareolus)co-exist in boreal forests in northern Scandinavia.Previous studies suggest that the 2 species interact interspecifically,the grey-sided vole being the dominant species.We tested the hypothesis that bank voles shift their diet due to competition with the dominant grey-sided vole by studying stable isotope ratios in both species.Muscle samples were taken from voles in patches of old forest occupied by only bank voles and patches of old forest occupied by both grey-sided voles and bank voles.We found that:(i)stable isotope ratios of bank voles differed in areas with and without grey-sided voles;and that(ii)the stable isotope ratios of bank voles were more similar to those of grey-sided voles in areas where grey-sided voles were absent.Our data suggests that grey-sided voles forced bank voles to change their diet due to interspecific competition.展开更多
Reading ability in the elderly means independence, and quality of life. In age-related macular degeneration (AMD), the main deficit is the loss of reading ability. The neovascular form is the leading cause of vision l...Reading ability in the elderly means independence, and quality of life. In age-related macular degeneration (AMD), the main deficit is the loss of reading ability. The neovascular form is the leading cause of vision loss in the developed world among people over 50 years of age. With ranibizumab (Lucentis) a drug treatment has become available, but, despite good outcome of visual acuity, patients often report that their reading ability has been affected. We aimed therefor to study reading performance with Tobii Eye Tracker in patients, treated with intravitrial Lucentis. Twenty patients, 15 female and 5 male (range 74 - 98 year), were recruited from St. Erik Eye Hospital. All had, before and after treatment, their reading speed, comprehension, fixations, saccadic eye movements measured while reading two texts with an equal readability rating. For all eye movement parameters, except the number of regressions per word, there was no statistically significant difference when comparing the results from before and after treatment. However, a statistically significant increase in the number of regressions per word after treatment as well as increased visual acuity and comprehension, were found. Reading is fundamental in our society and should be tested in order to fully understand a patient’s complaints;however, an increased VA will not necessarily equal an increased reading ability. The results also show that the Tobii system is suitable for evaluation of reading performance in a clinical setting, and can together with other tests, give valuable information about the patients complains and the outcome of a treatment.展开更多
A new polynomial formulation of variable step size linear multistep methods is pre- sented, where each k-step method is characterized by a fixed set of k - 1 or k parameters. This construction includes all methods of ...A new polynomial formulation of variable step size linear multistep methods is pre- sented, where each k-step method is characterized by a fixed set of k - 1 or k parameters. This construction includes all methods of maximal order （p = k for stiff, and p = k ＋ 1 for nonstiff problems）. Supporting time step adaptivity by construction, the new formulation is not based on extending classical fixed step size methods; instead classical methods are obtained as fixed step size restrictions within a unified framework. The methods are imple- mented in MATLAB, with local error estimation and a wide range of step size controllers. This provides a platform for investigating and comparing different multistep method in realistic operational conditions. Computational experiments show that the new multi- step method construction and implementation compares favorably to existing software, although variable order has not yet been included.展开更多
Asthma,rhinitis and eczema(allergic or non-allergic)have increased throughout the world during the last decades,especially among children.Changes in the indoor environment are suspected to be important causes.China ha...Asthma,rhinitis and eczema(allergic or non-allergic)have increased throughout the world during the last decades,especially among children.Changes in the indoor environment are suspected to be important causes.China has experienced a dramatic change in indoor environmental exposures during the past two decades.However,such changes and their associations with children’s asthma and other health aspects have not been thoroughly studied.China,Children,Homes,Health(CCHH),Phase I,was a cross-sectional questionnaire survey of 48219 children 1–8 years old in 10 Chinese cities during 2010–2012.The questionnaire includes the International Study of Asthma and Allergies in Childhood(ISAAC)core health questions and additional questions regarding housing,life habits and outdoor environment.In health analyses,children aged 3–6 years old were included.The prevalences of doctor diagnosed asthma varied from 1.7%to 9.8%(mean 6.8%),a large increase from 0.91%in 1999 and 1.50%in2000.The prevalence of wheeze,rhinitis and atopic eczema(last 12 months)varied from 13.9%to 23.7%,24.0%to 50.8%and4.8%to 15.8%,respectively.Taiyuan had the lowest prevalences of all illnesses and Shanghai the highest,except for wheezewhere the highest value was for Urumqi.We found(1)no obvious association between disease prevalences and ambient PM10concentrations and(2)higher prevalences of disease in humid climates with hot summers and cold winters,but with no centrally heated buildings.Associations between the diseases and economic status as indexed by Gross Domestic Product(GDP)requires further study.展开更多
High-Si spring steel was heat treated in three different ways： Quenching and tempering at 460 ℃ to obtain a tempered martensite microstructure, and austempering at 300 and 350 ℃, respectively, to obtain two differe...High-Si spring steel was heat treated in three different ways： Quenching and tempering at 460 ℃ to obtain a tempered martensite microstructure, and austempering at 300 and 350 ℃, respectively, to obtain two different carbide-free bainitic microstructures. In the steel austempered at 350 ℃, both the bainite lath thickness and retained austenite content were higher than those of the steel austempered at 300 ℃. Rotating-bending fatigue tests were done in order to evaluate the effect of each heat treatment on the high-cycle fatigue behavior of the steel. When the austempering temperature was 300 ℃, the endurance limit was increased by 25% despite a 5% reduction in tensile strength when compared with that of the quenched and tempered steel. The relationship between endurance limit [Rfat （50~）] and ultimate tensile strength （Rm） was higher for the austempered samples in comparison with that of the quenched and tempered material. Therefore, it is believed that the presence of retained austenite affects the relationship between endurance limit and tensile strength.展开更多
Why neurogenesis is attenuated in elderly individuals is an intriguing question that has raised renewed interest.Mechanisms associated with declined neurogenesis in the aged brain have been attributed to inflammatory ...Why neurogenesis is attenuated in elderly individuals is an intriguing question that has raised renewed interest.Mechanisms associated with declined neurogenesis in the aged brain have been attributed to inflammatory cytokines[1].More recently,a specific role for interferon-y(IFN-y)produced by CD8-expressing cytotoxic T cells has been implicated[2].These observations suggest a scenario in which neurogenesis,at least in part,is regulated by immune cells within the aging brain.This raises several interesting questions with regards to the characteristics of specific immune cells within the brain,the signals for their expansion and maintenance,and their role in affecting neurogenesis and cognition during normal brain aging.展开更多
硬聚氯乙烯料已被用作直径为0.4/0.6的局内电缆薄壁绝缘。绝缘挤塑采用一般的挤塑设备。该硬聚氯乙烯料是以 K 值为58的聚氯乙烯树脂为主体,不含任何主增塑剂。对硬聚氯乙烯绝缘料的测试结果,与标准的绝缘级增塑聚氯乙烯,尼龙12和改性...硬聚氯乙烯料已被用作直径为0.4/0.6的局内电缆薄壁绝缘。绝缘挤塑采用一般的挤塑设备。该硬聚氯乙烯料是以 K 值为58的聚氯乙烯树脂为主体,不含任何主增塑剂。对硬聚氯乙烯绝缘料的测试结果,与标准的绝缘级增塑聚氯乙烯,尼龙12和改性聚苯撑氧进行了比较。电缆设计为阻燃型,采用绕接方法接线。电缆可用增塑聚氯乙烯的或无卤的护套材料。展开更多
Using questionnaire is a common, efficient and cheap way to collect data in population-based epidemiological studies. However, there is a general trend of declining response rates leading to a higher risk for bias aff...Using questionnaire is a common, efficient and cheap way to collect data in population-based epidemiological studies. However, there is a general trend of declining response rates leading to a higher risk for bias affecting the validity of results. Use of anonymous questionnaires and/or other ways of distributions, e.g. via schools instead of postal, may increase response rates, but can also lead to other types of systematic errors. This study indicates that results from cross-sectional questionnaire studies differ depending on distribution method and whether the survey is anonymous or not. Also the official purpose of the survey may affect the outcome. When studying well-known risk-factors and health effects, potential methodological problems like reporting bias must be considered in cross sectional studies.展开更多
Indications of dementia disease include deterioration of memory, thinking, behaviour, and the ability to perform everyday activities. Any of these symptoms can lead to stress and difficulties organizing everyday life....Indications of dementia disease include deterioration of memory, thinking, behaviour, and the ability to perform everyday activities. Any of these symptoms can lead to stress and difficulties organizing everyday life. As a way to view factors that support human health and well-being despite stressful situations, Antonovsky introduced a salutogenic model. This model proposes that sense of coherence primarily determines physical and mental health i.e. psychological well-being. Having a sense of coherence in everyday life can reduce the impact of stress on the individual in everyday life. The study’s aim of this study was to explore how participants in existing support groups scored on the Sense of Coherence Scale (SOC), and what they perceived as contributory factors to a meaningful, manageable, and comprehensible everyday life in the presence of dementia using a mixed method. Persons with dementia had the highest scores on the SOC scale and their partners the lowest. Persons with dementia expressed that being with others who understood them made their everyday life comprehensible and manageable. Their partners expressed that learning about dementia was helpful in managing and comprehending everyday situations. The adult children expressed that it was meaningful to care for their parents and they scored slightly higher than the partners on the SOC scale. Long-term ongoing support supplemented with information and social support can contribute to the sense of coherence in persons with dementia and their next of kin.展开更多
Approximately 66 million people worldwide will suffer from dementia in 2030. The dementia’s impact affects people with the disorder and those in their social networks, most notably, their families. This study’s aim ...Approximately 66 million people worldwide will suffer from dementia in 2030. The dementia’s impact affects people with the disorder and those in their social networks, most notably, their families. This study’s aim was to explore the experiences of family relationships when a family member has dementia. We conducted semi-structured interviews with people diagnosed with dementia, their spouses and adult children. Seventeen participants were interviewed. All participants were recruited in open-ended ongoing structured support groups provided by a Swedish municipality in order to elicit the participants’ subjective experiences on family relationships after the dementia diagnosis. Researchers used content analysis to examine the transcripts. Two main themes were identified, one relating to changed relationships where the participants experienced longing, lost closeness, loneliness and changed sibling relationships. The second theme related to supporting relationships within the family with experiences such as kinship, shared responsibilities and love and appreciation. Support should therefore focus on creating relationships and giving opportunities for conversations about changes within the families and difficult decisions, creating family or team support for those who need it.展开更多
基金funding from the European Union’s Framework Programme for Research and Innovation Horizon 2020 under the Marie Skłodowska-Curie Grant Agreement No.860775the European Union’s Framework Programme for Research and Innovation Horizon 2020 under the Marie Skłodowska-Curie Grant Agreement No.955605+1 种基金the Swedish Research Council(VR 2021-05861)supported by the European Research Council through project StG-852529(MUCUS)。
文摘The combination of flow elasticity and inertia has emerged as a viable tool for focusing and manipulating particles using microfluidics.Although there is considerable interest in the field of elasto-inertial microfluidics owing to its potential applications,research on particle focusing has been mostly limited to low Reynolds numbers(Re<1),and particle migration toward equilibrium positions has not been extensively examined.In this work,we thoroughly studied particle focusing on the dynamic range of flow rates and particle migration using straight microchannels with a single inlet high aspect ratio.We initially explored several parameters that had an impact on particle focusing,such as the particle size,channel dimensions,concentration of viscoelastic fluid,and flow rate.Our experimental work covered a wide range of dimensionless numbers(0.05<Reynolds number<85,1.5<Weissenberg number<3800,5<Elasticity number<470)using 3,5,7,and 10μm particles.Our results showed that the particle size played a dominant role,and by tuning the parameters,particle focusing could be achieved at Reynolds numbers ranging from 0.2(1μL/min)to 85(250μL/min).Furthermore,we numerically and experimentally studied particle migration and reported differential particle migration for high-resolution separations of 5μm,7μm and 10μm particles in a sheathless flow at a throughput of 150μL/min.Our work elucidates the complex particle transport in elasto-inertial flows and has great potential for the development of high-throughput and high-resolution particle separation for biomedical and environmental applications.
基金This work is supported by ENIAC-JU Project Prominent Grant No 324189 and Tekes Grant No.40336/12 and Vinnova Grants Nos.2012-04301,2012-04287,and 2012-04314MM is supported by the Academy of Finland Grant Nos.288945 and 294119The work of Silex and KTH was funded in part through an Industrial Ph.D.grant from the Swedish Foundation for Strategic Research(SSF),Grant No.ID14-0033.
文摘Interposers with through-silicon vias(TSVs)play a key role in the three-dimensional integration and packaging of integrated circuits and microelectromechanical systems.In the current practice of fabricating interposers,solder balls are placed next to the vias;however,this approach requires a large foot print for the input/output(I/O)connections.Therefore,in this study,we investigate the possibility of placing the solder balls directly on top of the vias,thereby enabling a smaller pitch between the solder balls and an increased density of the I/O connections.To reach this goal,inkjet printing(that is,piezo and super inkjet)was used to successfully fill and planarize hollow metal TSVs with a dielectric polymer.The under bump metallization(UBM)pads were also successfully printed with inkjet technology on top of the polymer-filled vias,using either Ag or Au inks.The reliability of the TSV interposers was investigated by a temperature cycling stress test(−40℃ to+125℃).The stress test showed no impact on DC resistance of the TSVs;however,shrinkage and delamination of the polymer was observed,along with some micro-cracks in the UBM pads.For proof of concept,SnAgCu-based solder balls were jetted on the UBM pads.
文摘Water and energy are inextricably linked, and as a consequence both have to be addressed together. This is called the water-energy nexus. When access to either is limited, it becomes obvious that it is necessary to consider their interdependence. Population growth, climate change, urbanization, increasing living standards and food con- sumption will require an integrated approach where food, water and energy security are considered together. In this paper we examine water, energy and food security and their couplings. The nexus also creates conflicts between water use, energy extraction and generation as well as food production. Some of these conflicts are illustrated. It is argued that there is an urgent need for integrated planning and operation. Not only will better technology be needed, but also better integration of policies, organizations and political decisions.
文摘The prediction of the influent load is of great importance for the improvement of the control system to a large wastewater treatment plant. A systematic data analysis method is presented in this paper in order to estimate and predict the periodicity of the influent flow rate and ammonia （NH3） concentrations： 1） data filtering using wavelet decomposition and reconstruction; 2） typical cycle identification using power spectrum density analysis; 3） fitting and prediction model establishment based on an autoregressive model. To give meaningful information for feedforward control systems, predictions in different time scales are tested to compare the corresponding predicting accuracy. Considering the influence of the rainfalls, a linear fitting model is derived to estimate the relationship between flow rate trend and rain events. Measurements used to support coefficient fitting and model testing are acquired from two municipal wastewater treatment plants in China. The results show that 1） for both of the two plants, the periodicity affects the flow rate and NH3 concentrations in different cycles （especially cycles longer than 1 day）; 2） when the flow rate and NH3 concentrations present an obvious periodicity, the decreasing of prediction accuracy is not distinct with increasing of the prediction time scales; 3） the periodicity influence is larger than rainfalls; 4） the rainfalls will make the periodicity of flow rate less obvious in intensive rainy periods.
文摘Full-scale experiments have been carried out to adapt the activated sludge model ASM2d to include the influence of metal dosage （Fe^3＋ and Al^3＋） for phosphorus removal. Phosphorus removal rates, nitrification rates, as well as pH and sludge settling performance, were evaluated as functions of the metal dosages. Furthermore, models relating certain parameters to the dosage of chemicals have been derived. Corresponding parameters in the ASM2d and the secondary settler models, included in the Benchmark Simulation Model No 1 （BSM1）, have been modified to take the metal influence into consideration. Based on the effluent limits and penalty policy of China, an equivalent evaluation method was derived for the total cost assessment. A large number of 300-day steady-state and 14-day open-loop dynamic simulations were performed to demonstrate the difference in behavior between the original and the modified BSM1. The results show that 1） both in low and high mole concentrations, Fe^3＋ addition results in a higher phosphorus removal rate than Al^3＋; 2） the sludge settling velocity will increase due to the metal addition; 3） the respiration rate of the activated sludge is decreased more by the dosage of Al^3＋ than Fe^3＋; 4） the inhibition of Al^3＋ on the nitrification rate is stronger than that of Fe^3＋; 5） the total operating cost will reach the minimum point for smaller dosages of Fe^3＋, but always increase with Al^3＋ addition.
基金the anonymous reviewers for their constructive comments.Financial support was received from stiftelsen Oscar och Lili Lamms minne,from Helge Ax:son Johnsons stiftelse and from the Swedish Research Council FORMAS(Dnr 2017-00867).
文摘Grey-sided voles(Myodes rufocanus)and bank voles(Myodes glareolus)co-exist in boreal forests in northern Scandinavia.Previous studies suggest that the 2 species interact interspecifically,the grey-sided vole being the dominant species.We tested the hypothesis that bank voles shift their diet due to competition with the dominant grey-sided vole by studying stable isotope ratios in both species.Muscle samples were taken from voles in patches of old forest occupied by only bank voles and patches of old forest occupied by both grey-sided voles and bank voles.We found that:(i)stable isotope ratios of bank voles differed in areas with and without grey-sided voles;and that(ii)the stable isotope ratios of bank voles were more similar to those of grey-sided voles in areas where grey-sided voles were absent.Our data suggests that grey-sided voles forced bank voles to change their diet due to interspecific competition.
文摘Reading ability in the elderly means independence, and quality of life. In age-related macular degeneration (AMD), the main deficit is the loss of reading ability. The neovascular form is the leading cause of vision loss in the developed world among people over 50 years of age. With ranibizumab (Lucentis) a drug treatment has become available, but, despite good outcome of visual acuity, patients often report that their reading ability has been affected. We aimed therefor to study reading performance with Tobii Eye Tracker in patients, treated with intravitrial Lucentis. Twenty patients, 15 female and 5 male (range 74 - 98 year), were recruited from St. Erik Eye Hospital. All had, before and after treatment, their reading speed, comprehension, fixations, saccadic eye movements measured while reading two texts with an equal readability rating. For all eye movement parameters, except the number of regressions per word, there was no statistically significant difference when comparing the results from before and after treatment. However, a statistically significant increase in the number of regressions per word after treatment as well as increased visual acuity and comprehension, were found. Reading is fundamental in our society and should be tested in order to fully understand a patient’s complaints;however, an increased VA will not necessarily equal an increased reading ability. The results also show that the Tobii system is suitable for evaluation of reading performance in a clinical setting, and can together with other tests, give valuable information about the patients complains and the outcome of a treatment.
文摘A new polynomial formulation of variable step size linear multistep methods is pre- sented, where each k-step method is characterized by a fixed set of k - 1 or k parameters. This construction includes all methods of maximal order （p = k for stiff, and p = k ＋ 1 for nonstiff problems）. Supporting time step adaptivity by construction, the new formulation is not based on extending classical fixed step size methods; instead classical methods are obtained as fixed step size restrictions within a unified framework. The methods are imple- mented in MATLAB, with local error estimation and a wide range of step size controllers. This provides a platform for investigating and comparing different multistep method in realistic operational conditions. Computational experiments show that the new multi- step method construction and implementation compares favorably to existing software, although variable order has not yet been included.
基金supported by the National Natural Science Foundation of China(51136002,51076079,51006057)Ministry of Science and Technology of China(2012BAJ02B03)National High Technology Research and Development Program of China(2010AA064903)
文摘Asthma,rhinitis and eczema(allergic or non-allergic)have increased throughout the world during the last decades,especially among children.Changes in the indoor environment are suspected to be important causes.China has experienced a dramatic change in indoor environmental exposures during the past two decades.However,such changes and their associations with children’s asthma and other health aspects have not been thoroughly studied.China,Children,Homes,Health(CCHH),Phase I,was a cross-sectional questionnaire survey of 48219 children 1–8 years old in 10 Chinese cities during 2010–2012.The questionnaire includes the International Study of Asthma and Allergies in Childhood(ISAAC)core health questions and additional questions regarding housing,life habits and outdoor environment.In health analyses,children aged 3–6 years old were included.The prevalences of doctor diagnosed asthma varied from 1.7%to 9.8%(mean 6.8%),a large increase from 0.91%in 1999 and 1.50%in2000.The prevalence of wheeze,rhinitis and atopic eczema(last 12 months)varied from 13.9%to 23.7%,24.0%to 50.8%and4.8%to 15.8%,respectively.Taiyuan had the lowest prevalences of all illnesses and Shanghai the highest,except for wheezewhere the highest value was for Urumqi.We found(1)no obvious association between disease prevalences and ambient PM10concentrations and(2)higher prevalences of disease in humid climates with hot summers and cold winters,but with no centrally heated buildings.Associations between the diseases and economic status as indexed by Gross Domestic Product(GDP)requires further study.
基金the Centre for High Performance Steel at Lulea University of Technology for the financial support
文摘High-Si spring steel was heat treated in three different ways： Quenching and tempering at 460 ℃ to obtain a tempered martensite microstructure, and austempering at 300 and 350 ℃, respectively, to obtain two different carbide-free bainitic microstructures. In the steel austempered at 350 ℃, both the bainite lath thickness and retained austenite content were higher than those of the steel austempered at 300 ℃. Rotating-bending fatigue tests were done in order to evaluate the effect of each heat treatment on the high-cycle fatigue behavior of the steel. When the austempering temperature was 300 ℃, the endurance limit was increased by 25% despite a 5% reduction in tensile strength when compared with that of the quenched and tempered steel. The relationship between endurance limit [Rfat （50~）] and ultimate tensile strength （Rm） was higher for the austempered samples in comparison with that of the quenched and tempered material. Therefore, it is believed that the presence of retained austenite affects the relationship between endurance limit and tensile strength.
基金Open access funding provided by Karolinska Institute.
文摘Why neurogenesis is attenuated in elderly individuals is an intriguing question that has raised renewed interest.Mechanisms associated with declined neurogenesis in the aged brain have been attributed to inflammatory cytokines[1].More recently,a specific role for interferon-y(IFN-y)produced by CD8-expressing cytotoxic T cells has been implicated[2].These observations suggest a scenario in which neurogenesis,at least in part,is regulated by immune cells within the aging brain.This raises several interesting questions with regards to the characteristics of specific immune cells within the brain,the signals for their expansion and maintenance,and their role in affecting neurogenesis and cognition during normal brain aging.
文摘硬聚氯乙烯料已被用作直径为0.4/0.6的局内电缆薄壁绝缘。绝缘挤塑采用一般的挤塑设备。该硬聚氯乙烯料是以 K 值为58的聚氯乙烯树脂为主体,不含任何主增塑剂。对硬聚氯乙烯绝缘料的测试结果,与标准的绝缘级增塑聚氯乙烯,尼龙12和改性聚苯撑氧进行了比较。电缆设计为阻燃型,采用绕接方法接线。电缆可用增塑聚氯乙烯的或无卤的护套材料。
文摘Using questionnaire is a common, efficient and cheap way to collect data in population-based epidemiological studies. However, there is a general trend of declining response rates leading to a higher risk for bias affecting the validity of results. Use of anonymous questionnaires and/or other ways of distributions, e.g. via schools instead of postal, may increase response rates, but can also lead to other types of systematic errors. This study indicates that results from cross-sectional questionnaire studies differ depending on distribution method and whether the survey is anonymous or not. Also the official purpose of the survey may affect the outcome. When studying well-known risk-factors and health effects, potential methodological problems like reporting bias must be considered in cross sectional studies.
文摘Indications of dementia disease include deterioration of memory, thinking, behaviour, and the ability to perform everyday activities. Any of these symptoms can lead to stress and difficulties organizing everyday life. As a way to view factors that support human health and well-being despite stressful situations, Antonovsky introduced a salutogenic model. This model proposes that sense of coherence primarily determines physical and mental health i.e. psychological well-being. Having a sense of coherence in everyday life can reduce the impact of stress on the individual in everyday life. The study’s aim of this study was to explore how participants in existing support groups scored on the Sense of Coherence Scale (SOC), and what they perceived as contributory factors to a meaningful, manageable, and comprehensible everyday life in the presence of dementia using a mixed method. Persons with dementia had the highest scores on the SOC scale and their partners the lowest. Persons with dementia expressed that being with others who understood them made their everyday life comprehensible and manageable. Their partners expressed that learning about dementia was helpful in managing and comprehending everyday situations. The adult children expressed that it was meaningful to care for their parents and they scored slightly higher than the partners on the SOC scale. Long-term ongoing support supplemented with information and social support can contribute to the sense of coherence in persons with dementia and their next of kin.
文摘Approximately 66 million people worldwide will suffer from dementia in 2030. The dementia’s impact affects people with the disorder and those in their social networks, most notably, their families. This study’s aim was to explore the experiences of family relationships when a family member has dementia. We conducted semi-structured interviews with people diagnosed with dementia, their spouses and adult children. Seventeen participants were interviewed. All participants were recruited in open-ended ongoing structured support groups provided by a Swedish municipality in order to elicit the participants’ subjective experiences on family relationships after the dementia diagnosis. Researchers used content analysis to examine the transcripts. Two main themes were identified, one relating to changed relationships where the participants experienced longing, lost closeness, loneliness and changed sibling relationships. The second theme related to supporting relationships within the family with experiences such as kinship, shared responsibilities and love and appreciation. Support should therefore focus on creating relationships and giving opportunities for conversations about changes within the families and difficult decisions, creating family or team support for those who need it.
