Contagious bovine pleuro-pneumonia （CBPP） is one of the endemic and life-threatening livestock diseases in the arid and semi-arid land areas （ASALs） of Kenya, which justify the case for the control of livestock di...Contagious bovine pleuro-pneumonia （CBPP） is one of the endemic and life-threatening livestock diseases in the arid and semi-arid land areas （ASALs） of Kenya, which justify the case for the control of livestock diseases to avoid the spread of such diseases from the ASALs to the rest of the country, and a CBPP control quarantine line （CQL） that to help prevent the spread of CBPP from the ASALs of North-eastern Kenya to the rest of the country has been in existence since the colonial （pre-1963） times in Kenya. However, the livestock keepers in the ASALs view the CQL as an impediment to their main source of livelihoods because it entails livestock movement restrictions, thus constraining unfettered livestock marketing. Available literature shows that there is a dearth of information on the economics of livestock diseases control in Kenya in terms of its impacts on social welfare. Employing the CQL as a case study, this study shows that an application of analytic techniques that combine disease risk analysis and conventional cost-benefit modelling that incorporates some aspects that are specific to livestock diseases and their control strategies can generate indices of economic impacts of livestock diseases control on social welfare. The study finds that the livestock keepers and traders in Kenya do not consider CBPP a major problem to warrant livestock movement restrictions, yet the official records of the veterinary authorities indicate that CBPP is a major threat to the cattle industry in Kenya. Annually, the government spends substantial resources on the CQL operation and maintenance and also on CBPP surveillance and monitoring to contain the CBPP menace in Kenya. This study shows that such expenditures are economically and socially justifiable. Nevertheless, the study finds some operational inefficiencies in the enforcement of the CQL requirements. The authors, therefore, undertake an evaluation of alternative CBPP control strategies and conclude that it would be more cost effective to shift the CQL from its current location to the international borders of the arid districts, provided that this action is preceded by adequate CBPP control preparatory measures, as described in the paper.展开更多
Intracellular Ca2+ is vital for cell physiology.Disruption of Ca2+ homeostasis contributes to human diseases such as heart failure,neuron-degeneration,and diabetes.To ensure an effective intracellular Ca2+ dynamics,va...Intracellular Ca2+ is vital for cell physiology.Disruption of Ca2+ homeostasis contributes to human diseases such as heart failure,neuron-degeneration,and diabetes.To ensure an effective intracellular Ca2+ dynamics,various Ca2+ transport proteins localized in different cellular regions have to work in coordination.The central role of mitochondrial Ca2+ transport mechanisms in responding to physiological Ca2+ pulses in cytosol is to take up Ca2+ for regulating energy production and shaping the amplitude and duration of Ca2+ transients in various micro-domains.Since the discovery that isolated mitochondria can take up large quantities of Ca2+ approximately 5 decades ago,extensive studies have been focused on the functional characterization and implication of ion channels that dictate Ca2+ transport across the inner mitochondrial membrane.The mitochondrial Ca2+ uptake sensitive to non-specific inhibitors ruthenium red and Ru360 has long been considered as the activity of mitochondrial Ca2+ uniporter(MCU) .The general consensus is that MCU is dominantly or exclusively responsible for the mitochondrial Ca2+ influx.Since multiple Ca2+ influx mechanisms(e.g.L-,T-,and N-type Ca2+ channel) have their unique functions in the plasma membrane,it is plausible that mitochondrial inner membrane has more than just MCU to decode complex intracellular Ca2+ signaling in various cell types.During the last decade,four molecular identities related to mitochondrial Ca2+ influx mechanisms have been identified.These are mitochondrial ryanodine receptor,mitochondrial uncoupling proteins,LETM1(Ca2+ /H+ exchanger) ,and MCU and its Ca2+ sensing regulatory subunit MICU1.Here,we briefly review recent progress in these and other reported mitochondrial Ca2+ influx pathways and their differences in kinetics,Ca2+ dependence,and pharmacological characteristics.Their potential physiological and pathological implications are also discussed.展开更多
Tailoring tire pore structure and surface chemistry of graphene-based laminates is essentially important for their applications as separation membranes. Usually, pure graphene oxide （GO） and completely reduced GO （...Tailoring tire pore structure and surface chemistry of graphene-based laminates is essentially important for their applications as separation membranes. Usually, pure graphene oxide （GO） and completely reduced GO （rGO） membranes suffer florn low water permeance because of the lack of pristine graphitic sp2 domains and very small interlayer spacing, respectively. In this work, we studied the influence of reduction degree on the structure and separation pertornrance of rGO membranes, tt was found that weak reduction retains the good dispersion and hydrophilicity of GO nanosheets. More importantly, it increases the number of pristine graphitic sp2 domains in rGO nanosheets while keeping the large interlayer spacing of the GO membranes in most regions at the same time. The resultant mernbranes show a high water permeance of 56.3 L m^-2 h^ -1 bar^ -1, which is about 4 times and over 10^4 times larger tban those of the GO and completely reduced rGO membranes, respectively, and high rejection over 95700 for various dyes. Furthermore, they show better structure stability and more superior separation perfor- mance than GO membranes in acid and alkali environments.展开更多
文摘Contagious bovine pleuro-pneumonia （CBPP） is one of the endemic and life-threatening livestock diseases in the arid and semi-arid land areas （ASALs） of Kenya, which justify the case for the control of livestock diseases to avoid the spread of such diseases from the ASALs to the rest of the country, and a CBPP control quarantine line （CQL） that to help prevent the spread of CBPP from the ASALs of North-eastern Kenya to the rest of the country has been in existence since the colonial （pre-1963） times in Kenya. However, the livestock keepers in the ASALs view the CQL as an impediment to their main source of livelihoods because it entails livestock movement restrictions, thus constraining unfettered livestock marketing. Available literature shows that there is a dearth of information on the economics of livestock diseases control in Kenya in terms of its impacts on social welfare. Employing the CQL as a case study, this study shows that an application of analytic techniques that combine disease risk analysis and conventional cost-benefit modelling that incorporates some aspects that are specific to livestock diseases and their control strategies can generate indices of economic impacts of livestock diseases control on social welfare. The study finds that the livestock keepers and traders in Kenya do not consider CBPP a major problem to warrant livestock movement restrictions, yet the official records of the veterinary authorities indicate that CBPP is a major threat to the cattle industry in Kenya. Annually, the government spends substantial resources on the CQL operation and maintenance and also on CBPP surveillance and monitoring to contain the CBPP menace in Kenya. This study shows that such expenditures are economically and socially justifiable. Nevertheless, the study finds some operational inefficiencies in the enforcement of the CQL requirements. The authors, therefore, undertake an evaluation of alternative CBPP control strategies and conclude that it would be more cost effective to shift the CQL from its current location to the international borders of the arid districts, provided that this action is preceded by adequate CBPP control preparatory measures, as described in the paper.
基金supported by NIH grants(Grant Nos.HL-033333 and HL093671)to Shey-Shing Sheu
文摘Intracellular Ca2+ is vital for cell physiology.Disruption of Ca2+ homeostasis contributes to human diseases such as heart failure,neuron-degeneration,and diabetes.To ensure an effective intracellular Ca2+ dynamics,various Ca2+ transport proteins localized in different cellular regions have to work in coordination.The central role of mitochondrial Ca2+ transport mechanisms in responding to physiological Ca2+ pulses in cytosol is to take up Ca2+ for regulating energy production and shaping the amplitude and duration of Ca2+ transients in various micro-domains.Since the discovery that isolated mitochondria can take up large quantities of Ca2+ approximately 5 decades ago,extensive studies have been focused on the functional characterization and implication of ion channels that dictate Ca2+ transport across the inner mitochondrial membrane.The mitochondrial Ca2+ uptake sensitive to non-specific inhibitors ruthenium red and Ru360 has long been considered as the activity of mitochondrial Ca2+ uniporter(MCU) .The general consensus is that MCU is dominantly or exclusively responsible for the mitochondrial Ca2+ influx.Since multiple Ca2+ influx mechanisms(e.g.L-,T-,and N-type Ca2+ channel) have their unique functions in the plasma membrane,it is plausible that mitochondrial inner membrane has more than just MCU to decode complex intracellular Ca2+ signaling in various cell types.During the last decade,four molecular identities related to mitochondrial Ca2+ influx mechanisms have been identified.These are mitochondrial ryanodine receptor,mitochondrial uncoupling proteins,LETM1(Ca2+ /H+ exchanger) ,and MCU and its Ca2+ sensing regulatory subunit MICU1.Here,we briefly review recent progress in these and other reported mitochondrial Ca2+ influx pathways and their differences in kinetics,Ca2+ dependence,and pharmacological characteristics.Their potential physiological and pathological implications are also discussed.
基金supported by the National Key Research and Development Program of China(2016YFA0200101)the National Natural Science Foundation of China(51325205,51290273,and51521091)Chinese Academy of Sciences(KGZD-EW-303-1,KGZDEW-T06,174321KYSB20160011,and XDPB06)
文摘Tailoring tire pore structure and surface chemistry of graphene-based laminates is essentially important for their applications as separation membranes. Usually, pure graphene oxide （GO） and completely reduced GO （rGO） membranes suffer florn low water permeance because of the lack of pristine graphitic sp2 domains and very small interlayer spacing, respectively. In this work, we studied the influence of reduction degree on the structure and separation pertornrance of rGO membranes, tt was found that weak reduction retains the good dispersion and hydrophilicity of GO nanosheets. More importantly, it increases the number of pristine graphitic sp2 domains in rGO nanosheets while keeping the large interlayer spacing of the GO membranes in most regions at the same time. The resultant mernbranes show a high water permeance of 56.3 L m^-2 h^ -1 bar^ -1, which is about 4 times and over 10^4 times larger tban those of the GO and completely reduced rGO membranes, respectively, and high rejection over 95700 for various dyes. Furthermore, they show better structure stability and more superior separation perfor- mance than GO membranes in acid and alkali environments.
