Type A lactic acidosis resulted from hypoxic mitochondrial dysfunction is an independent predictor of mortality for critically ill patients. However, current therapeutic agents are still in shortage and can even be ha...Type A lactic acidosis resulted from hypoxic mitochondrial dysfunction is an independent predictor of mortality for critically ill patients. However, current therapeutic agents are still in shortage and can even be harmful. This paper reviewed data regarding lactic acidosis treatment and recommended that pyruvate might be a potential alkalizer to correct type A lactic acidosis in future clinical practice. Pyruvate is a key energy metabolic substrate and a pyruvate dehydrogenase(PDH) activator with several unique beneficial biological properties, including anti-oxidant and antiinflammatory effects and the ability to activate the hypoxia-inducible factor-1(HIF-1α)-erythropoietin(EPO) signal pathway. Pyruvate preserves glucose metabolism and cellular energetics better than bicarbonate, lactate, acetate and malate in the efficient correction of hypoxic lactic acidosis and shows few side effects. Therefore, application of pyruvate may be promising and safe as a novel therapeutic strategy in hypoxic lactic acidosis correction accompanied with multi-organ protection in critical care patients.展开更多
Background:Plasma expanders are widely used for acute normovolemic hemodilution(ANH).However,existing studies have not focused on large-volume infusion with colloidal plasma expanders,and there is a lack of studies th...Background:Plasma expanders are widely used for acute normovolemic hemodilution(ANH).However,existing studies have not focused on large-volume infusion with colloidal plasma expanders,and there is a lack of studies that compare the effects of different plasma expanders.Methods:The viscosity,hydrodynamic radius(Rh)and colloid osmotic pressure(COP)of plasma expanders were determined by a cone-plate viscometer,Zetasizer and cut-off membrane,respectively.Sixty male rats were randomized into five groups with Gelofusine(Gel),Hydroxyethyl Starch 200/0.5(HES200),Hydroxyethyl Starch 130/0.4(HES130),Hydroxyethyl Starch 40(HES40),and Dextran 40(Dex40),with 12 rats used in each group to build the ANH model.ANH was performed by the withdrawal of blood and simultaneous infusion of plasma expanders.Acid-base,lactate,blood gas and physiological parameters were detected.Results:Gel had a lower intrinsic viscosity than HES200 and HES130(P<0.01),but at a low shear rate in a mixture of colloids,red cells and plasma,Gel had a higher viscosity(P<0.05 or P<0.01,respectively).For hydroxyethyl starch plasma expanders,the COP at a certain concentration decreases from 11.1 mmHg to 6.1 mmHg with the increase of Rh from 10.7 nm to 20.2 nm.A severe ANH model,with the hematocrit of 40%of the baseline level,was established and accompanied by disturbances in acid-base,lactate and blood gas parameters.At the end of ANH and 60 min afterward,the Dex40 group showed a worse outcome in maintaining the acid-base balance and systemic oxygenation compared to the other groups.The systolic blood pressure(SBP),diastolic blood pressure(DBP),and mean arterial pressure(MAP)decreased significantly in all groups at the end of ANH.The DBP and MAP in the Dex40 group further decreased 60 min after the end of ANH.During the process of ANH,the Dex40 group showed a drop and recovery in SBP,DBP and MAP.The DBP and MAP in the HES200 group were significantly higher than those in the other groups at some time points(P<0.05 or P<0.01).Conclusions:Gel had a low intrinsic viscosity but may increase the whole blood viscosity at low shear rates.Rh and COP showed a strong correlation among hydroxyethyl starch plasma expanders.Dex40 showed a worse outcome in maintaining the acid-base balance and systemic oxygenation compared to the other plasma expanders.During the process of ANH,Dex40 displayed a V-shaped recovery pattern for blood pressure,and HES200 had the advantage in sustaining the DBP and MAP at some time points.展开更多
BACKGROUND： Subthalamic nucleus-high frequency stimulation （STN-HFS） plays an important role in the treatment of Parkinson＇s disease, but the mechanisms underlying STN-HFS remain unclear. Some studies have demonst...BACKGROUND： Subthalamic nucleus-high frequency stimulation （STN-HFS） plays an important role in the treatment of Parkinson＇s disease, but the mechanisms underlying STN-HFS remain unclear. Some studies have demonstrated that STN stimulation inhibits the firing activity of substantia nigra pars reticulata neurons. OBJECTIVE： To investigate the effects of different-frequency STN stimulation and microiontophoresis of gamma-aminobutyric acid （GABA） and its antagonist, bicuculline, on spontaneous firing activity in a rat model of Parkinson＇s disease, and to analyze the action pathway of high frequency stimulation in firing activity inhibition of substantia nigra pars reticulata neurons. DESIGN, TIME AND SETTING： This neuroelectrophysiological, animal experiment was performed at the Electrophysiology Laboratory of Liaoning Medical University, China from March to August 2008. MATERIALS： 6-hydroxydopamine （6-OHDA） （Sigma, USA）, A320R isolated stimulus and DAM80 preamplifier （World Precision Instruments, USA）, 6400A microiontophoresis apparatus （Dagan, USA）, and Spike 2 biological signal acquisition system （CED, UK） were used in this study. METHODS： A total of 20 Sprague Dawley rats were used to establish a Parkinson＇s disease model via injection of 6-OHDA into the right striatum. Electrical stimulation （0.06-ms width, 0.4-mA intensity 20-200-Hz frequency, 5-second train duration） was delivered to the subthalamic nucleus. Peripheral channels were separately filled with GABA （pH 3.5, 0.2 mol/L）, bicuculline （pH 4.0, 0.01 mol/L）, and NaCI （pH 7.0, 3 mol/L）. The electrode was positioned with a WK-2 microelectrode propulsion device, and was slowly inserted into the substantia nigra pars reticulata to record spontaneous firing activity of substantia nigra pars reticulata neurons. MAIN OUTCOME MEASURES： The number and firing rate of substantia nigra pars reticulata neurons which were either inhibited or excited were measured. RESULTS： Substantia nigra pars reticulata neurons were inhibited by STN stimulation. The proportion of inhibited substantia nigra pars reticulata neurons increased with increasing stimulation frequency. GABA had a tonic inhibitory effect on substantia nigra pars reticulata neurons. Microiontophoresis of bicuculline suppressed the inhibitory effect of STN-HFS on 67% （4/6） of substantia nigra pars reticulata neurons. CONCLUSION： STN-HFS ameliorated abnormal activity in substantia nigra pars reticulata neurons via the inhibitory effect of GABA treatment in a rat model of Parkinson＇s disease.展开更多
Well-established fact shows that the fixed spectrum allocation policy conveys to the low spectrum utilization. The cognitive radio technique promises to improve the low efficiency. This paper proposes an optimized acc...Well-established fact shows that the fixed spectrum allocation policy conveys to the low spectrum utilization. The cognitive radio technique promises to improve the low efficiency. This paper proposes an optimized access strategy combining overlay scheme and underlay scheme for the cognitive radio. We model the service state of the system as a continuous-time Markov model. Based on the service state, the overlay manner or/and the underlay manner is/are used by the secondary users. When the primary user is not transmitting and only one secondary user has the requirement to transmit, the secondary system adopts the overlay scheme. When the primary user is transmitting and the secondary users want to transmit simultaneously, an underlay scheme with an access probability is adopted. We obtain the optimal access probability in a closed form which maximizes the overall system throughput.展开更多
In this paper, the performance of multichannel transmission in cognitive radio is studied. Both QoS constraints and interference limitations are considered. The activities of the primary users (PU)s are initially dete...In this paper, the performance of multichannel transmission in cognitive radio is studied. Both QoS constraints and interference limitations are considered. The activities of the primary users (PU)s are initially detected by cognitive users (CU)s who perform sensing process over multiple channels. They transmit in a single channel at variable power and rates depending on the channel sensing decisions and the fading environment. The cognitive operation is modeled as a state transition model in which all possible scenarios are studied. The QoS constraint of the cognitive users is investigated through statistical analysis. Analytical form for the effective capacity of the cognitive radio channel is found. Optimal power allocation and optimal channel selection criterion are obtained. Impact of several parameters on the transmission performance, as channel sensing parameters, number of available channels, fading and other, are identified through numerical example.展开更多
Epstein Barr virus infection is believed to play a role in the development of nasopharyngeal carcinoma. In order to investigate the function of EBV in epithelial cell, proteomic methods were used to find and identify ...Epstein Barr virus infection is believed to play a role in the development of nasopharyngeal carcinoma. In order to investigate the function of EBV in epithelial cell, proteomic methods were used to find and identify the differential proteins and expected to elucidate the mechanism of EBV. Altered protein expressions were found between 293 cell (HEK293) and EBV infected cell (293-EBV). In this study, we separated differential expressed proteins using 2D-DIGE method while matrix-assisted laser desorption/ionization tandem time of flight mass spectrometry (MALDI-TOF-MS) method was used to identify proteins. The results showed that 14 proteins were up regulated and 3 proteins were down regulated in 293-EBV cells. Bioinformatic analysis showed that these proteins are involved in cell proliferation, metastasis, apoptosis, metabolism, and signal transduction. Western blotting analysis was further carried out to verify the MS results. Thus, EBV may exert its functions by mediating differential expression of these proteins.展开更多
Nowadays both satellite and terrestrial networks are expanding rapidly to meet the ever-increasing demands for higher throughput,lower latency,and wider coverage.However,spectrum scarcity places obstacles in the susta...Nowadays both satellite and terrestrial networks are expanding rapidly to meet the ever-increasing demands for higher throughput,lower latency,and wider coverage.However,spectrum scarcity places obstacles in the sustainable development.To accommodate the expanding network within a limited spectrum,spectrum sharing is deemed as a promising candidate.Particularly,cognitive radio(CR)has been proposed in the literature to allow satellite and terrestrial networks to share their spectrum dynamically.However,the existing CR-based schemes are found to be impractical and inefficient because they neglect the difficulty in obtaining the accurate and timely environment perception in satellite communications and only focus on link-level coexistence with limited interoperability.In this paper,we propose an intelligent spectrum management framework based on software defined network(SDN)and artificial intelligence(AI).Specifically,SDN transforms the heterogenous satellite and terrestrial networks into an integrated satellite and terrestrial network(ISTN)with reconfigurability and interoperability.AI is further used to make predictive environment perception and to configure the network for optimal resource allocation.Briefly,the proposed framework provides a new paradigm to integrate and exploit the spectrum of satellite and terrestrial networks.展开更多
2-aryl-3-(naphthalene-1 or 2-yl)-1,3-thiazolidin-4-ones 4 and 5 were synthesized in 41%–67%yield by using microwave-assisted one-pot protocol.The structures of the new compounds 4l,4m,5c,5e,5g,5h,and 5j–5m were conf...2-aryl-3-(naphthalene-1 or 2-yl)-1,3-thiazolidin-4-ones 4 and 5 were synthesized in 41%–67%yield by using microwave-assisted one-pot protocol.The structures of the new compounds 4l,4m,5c,5e,5g,5h,and 5j–5m were confirmed by IR,NMR,MS,and elemental analysis.The antimicrobial activities of the compounds against Pseudomonas syringae pv.lachrymans(Smith et Bryan)Young,Dye&Wilkie,Botrytis cinerea Pers.,and Sphaerotheca fusca Blum.were examined.Some of the compounds showed good antifungical activity against Sphaerotheca fusca Blum.展开更多
基金supported by the National Natural Science Foundation of China(No.81700181,No.81600148)
文摘Type A lactic acidosis resulted from hypoxic mitochondrial dysfunction is an independent predictor of mortality for critically ill patients. However, current therapeutic agents are still in shortage and can even be harmful. This paper reviewed data regarding lactic acidosis treatment and recommended that pyruvate might be a potential alkalizer to correct type A lactic acidosis in future clinical practice. Pyruvate is a key energy metabolic substrate and a pyruvate dehydrogenase(PDH) activator with several unique beneficial biological properties, including anti-oxidant and antiinflammatory effects and the ability to activate the hypoxia-inducible factor-1(HIF-1α)-erythropoietin(EPO) signal pathway. Pyruvate preserves glucose metabolism and cellular energetics better than bicarbonate, lactate, acetate and malate in the efficient correction of hypoxic lactic acidosis and shows few side effects. Therefore, application of pyruvate may be promising and safe as a novel therapeutic strategy in hypoxic lactic acidosis correction accompanied with multi-organ protection in critical care patients.
基金supported by the National Key Research and Development Program of China(2018YFC1106503)。
文摘Background:Plasma expanders are widely used for acute normovolemic hemodilution(ANH).However,existing studies have not focused on large-volume infusion with colloidal plasma expanders,and there is a lack of studies that compare the effects of different plasma expanders.Methods:The viscosity,hydrodynamic radius(Rh)and colloid osmotic pressure(COP)of plasma expanders were determined by a cone-plate viscometer,Zetasizer and cut-off membrane,respectively.Sixty male rats were randomized into five groups with Gelofusine(Gel),Hydroxyethyl Starch 200/0.5(HES200),Hydroxyethyl Starch 130/0.4(HES130),Hydroxyethyl Starch 40(HES40),and Dextran 40(Dex40),with 12 rats used in each group to build the ANH model.ANH was performed by the withdrawal of blood and simultaneous infusion of plasma expanders.Acid-base,lactate,blood gas and physiological parameters were detected.Results:Gel had a lower intrinsic viscosity than HES200 and HES130(P<0.01),but at a low shear rate in a mixture of colloids,red cells and plasma,Gel had a higher viscosity(P<0.05 or P<0.01,respectively).For hydroxyethyl starch plasma expanders,the COP at a certain concentration decreases from 11.1 mmHg to 6.1 mmHg with the increase of Rh from 10.7 nm to 20.2 nm.A severe ANH model,with the hematocrit of 40%of the baseline level,was established and accompanied by disturbances in acid-base,lactate and blood gas parameters.At the end of ANH and 60 min afterward,the Dex40 group showed a worse outcome in maintaining the acid-base balance and systemic oxygenation compared to the other groups.The systolic blood pressure(SBP),diastolic blood pressure(DBP),and mean arterial pressure(MAP)decreased significantly in all groups at the end of ANH.The DBP and MAP in the Dex40 group further decreased 60 min after the end of ANH.During the process of ANH,the Dex40 group showed a drop and recovery in SBP,DBP and MAP.The DBP and MAP in the HES200 group were significantly higher than those in the other groups at some time points(P<0.05 or P<0.01).Conclusions:Gel had a low intrinsic viscosity but may increase the whole blood viscosity at low shear rates.Rh and COP showed a strong correlation among hydroxyethyl starch plasma expanders.Dex40 showed a worse outcome in maintaining the acid-base balance and systemic oxygenation compared to the other plasma expanders.During the process of ANH,Dex40 displayed a V-shaped recovery pattern for blood pressure,and HES200 had the advantage in sustaining the DBP and MAP at some time points.
文摘BACKGROUND： Subthalamic nucleus-high frequency stimulation （STN-HFS） plays an important role in the treatment of Parkinson＇s disease, but the mechanisms underlying STN-HFS remain unclear. Some studies have demonstrated that STN stimulation inhibits the firing activity of substantia nigra pars reticulata neurons. OBJECTIVE： To investigate the effects of different-frequency STN stimulation and microiontophoresis of gamma-aminobutyric acid （GABA） and its antagonist, bicuculline, on spontaneous firing activity in a rat model of Parkinson＇s disease, and to analyze the action pathway of high frequency stimulation in firing activity inhibition of substantia nigra pars reticulata neurons. DESIGN, TIME AND SETTING： This neuroelectrophysiological, animal experiment was performed at the Electrophysiology Laboratory of Liaoning Medical University, China from March to August 2008. MATERIALS： 6-hydroxydopamine （6-OHDA） （Sigma, USA）, A320R isolated stimulus and DAM80 preamplifier （World Precision Instruments, USA）, 6400A microiontophoresis apparatus （Dagan, USA）, and Spike 2 biological signal acquisition system （CED, UK） were used in this study. METHODS： A total of 20 Sprague Dawley rats were used to establish a Parkinson＇s disease model via injection of 6-OHDA into the right striatum. Electrical stimulation （0.06-ms width, 0.4-mA intensity 20-200-Hz frequency, 5-second train duration） was delivered to the subthalamic nucleus. Peripheral channels were separately filled with GABA （pH 3.5, 0.2 mol/L）, bicuculline （pH 4.0, 0.01 mol/L）, and NaCI （pH 7.0, 3 mol/L）. The electrode was positioned with a WK-2 microelectrode propulsion device, and was slowly inserted into the substantia nigra pars reticulata to record spontaneous firing activity of substantia nigra pars reticulata neurons. MAIN OUTCOME MEASURES： The number and firing rate of substantia nigra pars reticulata neurons which were either inhibited or excited were measured. RESULTS： Substantia nigra pars reticulata neurons were inhibited by STN stimulation. The proportion of inhibited substantia nigra pars reticulata neurons increased with increasing stimulation frequency. GABA had a tonic inhibitory effect on substantia nigra pars reticulata neurons. Microiontophoresis of bicuculline suppressed the inhibitory effect of STN-HFS on 67% （4/6） of substantia nigra pars reticulata neurons. CONCLUSION： STN-HFS ameliorated abnormal activity in substantia nigra pars reticulata neurons via the inhibitory effect of GABA treatment in a rat model of Parkinson＇s disease.
文摘Well-established fact shows that the fixed spectrum allocation policy conveys to the low spectrum utilization. The cognitive radio technique promises to improve the low efficiency. This paper proposes an optimized access strategy combining overlay scheme and underlay scheme for the cognitive radio. We model the service state of the system as a continuous-time Markov model. Based on the service state, the overlay manner or/and the underlay manner is/are used by the secondary users. When the primary user is not transmitting and only one secondary user has the requirement to transmit, the secondary system adopts the overlay scheme. When the primary user is transmitting and the secondary users want to transmit simultaneously, an underlay scheme with an access probability is adopted. We obtain the optimal access probability in a closed form which maximizes the overall system throughput.
文摘In this paper, the performance of multichannel transmission in cognitive radio is studied. Both QoS constraints and interference limitations are considered. The activities of the primary users (PU)s are initially detected by cognitive users (CU)s who perform sensing process over multiple channels. They transmit in a single channel at variable power and rates depending on the channel sensing decisions and the fading environment. The cognitive operation is modeled as a state transition model in which all possible scenarios are studied. The QoS constraint of the cognitive users is investigated through statistical analysis. Analytical form for the effective capacity of the cognitive radio channel is found. Optimal power allocation and optimal channel selection criterion are obtained. Impact of several parameters on the transmission performance, as channel sensing parameters, number of available channels, fading and other, are identified through numerical example.
文摘Epstein Barr virus infection is believed to play a role in the development of nasopharyngeal carcinoma. In order to investigate the function of EBV in epithelial cell, proteomic methods were used to find and identify the differential proteins and expected to elucidate the mechanism of EBV. Altered protein expressions were found between 293 cell (HEK293) and EBV infected cell (293-EBV). In this study, we separated differential expressed proteins using 2D-DIGE method while matrix-assisted laser desorption/ionization tandem time of flight mass spectrometry (MALDI-TOF-MS) method was used to identify proteins. The results showed that 14 proteins were up regulated and 3 proteins were down regulated in 293-EBV cells. Bioinformatic analysis showed that these proteins are involved in cell proliferation, metastasis, apoptosis, metabolism, and signal transduction. Western blotting analysis was further carried out to verify the MS results. Thus, EBV may exert its functions by mediating differential expression of these proteins.
基金National Natural Science Foundation of China(61631005)National Natural Science Foundation of China(U1801261)+3 种基金National Natural Science Foundation of China(61571100)National Key R&D Program of China(2018YFB1801105)Central Universities(ZYGX2019Z022)Programme of Introducing Talents of Discipline to Universities(B20064)。
文摘Nowadays both satellite and terrestrial networks are expanding rapidly to meet the ever-increasing demands for higher throughput,lower latency,and wider coverage.However,spectrum scarcity places obstacles in the sustainable development.To accommodate the expanding network within a limited spectrum,spectrum sharing is deemed as a promising candidate.Particularly,cognitive radio(CR)has been proposed in the literature to allow satellite and terrestrial networks to share their spectrum dynamically.However,the existing CR-based schemes are found to be impractical and inefficient because they neglect the difficulty in obtaining the accurate and timely environment perception in satellite communications and only focus on link-level coexistence with limited interoperability.In this paper,we propose an intelligent spectrum management framework based on software defined network(SDN)and artificial intelligence(AI).Specifically,SDN transforms the heterogenous satellite and terrestrial networks into an integrated satellite and terrestrial network(ISTN)with reconfigurability and interoperability.AI is further used to make predictive environment perception and to configure the network for optimal resource allocation.Briefly,the proposed framework provides a new paradigm to integrate and exploit the spectrum of satellite and terrestrial networks.
基金The financial supports from the National Natural Science Foundation of China(Grant No.20672027)the Natural Science Foundation of Hebei(2005000106,2008000588)+1 种基金the Research Foundation of the Ministry of Education of China(206013)the Postdoctoral Foundation of China are gratefully acknowledged.
文摘2-aryl-3-(naphthalene-1 or 2-yl)-1,3-thiazolidin-4-ones 4 and 5 were synthesized in 41%–67%yield by using microwave-assisted one-pot protocol.The structures of the new compounds 4l,4m,5c,5e,5g,5h,and 5j–5m were confirmed by IR,NMR,MS,and elemental analysis.The antimicrobial activities of the compounds against Pseudomonas syringae pv.lachrymans(Smith et Bryan)Young,Dye&Wilkie,Botrytis cinerea Pers.,and Sphaerotheca fusca Blum.were examined.Some of the compounds showed good antifungical activity against Sphaerotheca fusca Blum.
