BACKGROUND Helicobacter pylori(H.pylori)eradication rates have declined with the rise of antibiotic-resistant strains in recent years.Although highly effective with a low prevalence of resistance,standard dose tetracy...BACKGROUND Helicobacter pylori(H.pylori)eradication rates have declined with the rise of antibiotic-resistant strains in recent years.Although highly effective with a low prevalence of resistance,standard dose tetracycline is associated with frequent adverse events.The efficacy and safety of low-dose tetracycline as part of tetra-cycline and amoxicillin-containing bismuth quadruple therapy are not well described.AIM To compare the efficacy and safety of low-dose compared to standard dose tetracycline with combined amoxicillin-containing bismuth quadruple therapy in patients with H.pylori infection.METHODS Consecutive patients with H.pylori infection receiving tetracycline,amoxicillin,proton pump inhibitor,and bismuth for 14 days at Sir Run Run Shaw Hospital(1/2022-6/2023)were evaluated.The low-dose tetracycline group received tetracycline 500 mg twice daily(bid)while the standard dose group received 750 mg bid or 500 mg three times daily(tid).Primary endpoints were H.pylori eradication rate and treatment-related adverse events.展开更多
The deoxygenation of organic acids, important biomass feedstocks and derivatives, to synthesize hydrocarbon products under mild electrochemical conditions, holds significant importance for the production of carbon-neu...The deoxygenation of organic acids, important biomass feedstocks and derivatives, to synthesize hydrocarbon products under mild electrochemical conditions, holds significant importance for the production of carbon-neutral biofuels. There is still limited research on the influential factors of the electrochemical decarboxylation reaction of medium-chain fatty acids. In this study, n-octanoic acid (OA) was chosen as the research subject to investigate the electrochemical decarboxylation behavior of OA on a platinum electrode, focusing on the influence of different alkali metal cations (Li^(+), Na^(+), K^(+)), common anions (SO^(4)^(2−), Cl^(−)), and electrolyte pH. It was found that KOH as an electrolyte exhibited the best performance for OA. Possibly, the larger size of K^(+) increased the alkalinity of the electrode surface, facilitating OA deprotonation. LiOH electrolyte reduced the solubility of OA, thereby inhibiting the decarboxylation reaction. SO^(4)^(2−) exhibited a weak promoting effect on the decarboxylation reaction of OA, while Cl^(−) showed no adverse effect although Cl^(−) may adsorb on the electrode surface. Furthermore, unlike short-chain fatty acids, medium-chain OA can only achieve efficient decarboxylation under alkaline conditions due to its solubility properties. This study provides references and foundations for future efforts to enhance the efficiency of electrochemical decarboxylation synthesis of hydrocarbon biofuels from medium-chain fatty acids.展开更多
Parent and alkylated polycyclic aromatic hydrocarbons(alkyl-PAHs),which are a class of important toxic components of crude oil especially in the marine environment,exhibit adverse effects on aquatic life and potential...Parent and alkylated polycyclic aromatic hydrocarbons(alkyl-PAHs),which are a class of important toxic components of crude oil especially in the marine environment,exhibit adverse effects on aquatic life and potentially pose a human health risk.However,the lack of chronic toxicity data is one of the hindrances for alkylPAHs when assessing their ecological risks.In this study,predicted no-effect concentrations(PNECs)in seawater and marine sediment for ten parent-and alkyl-PAHs were derived by applying species sensitivity distributions(SSDs)and quantitative structure-activity relationships(QSARs).The local area,Dalian Bay,where an oil-spilled accident happened in 2010,was chosen as a case site to assess ecological risks for ten PAHs in surface seawaters and marine sediments.Their PNECs in seawater and sediment for protecting aquatic organisms in marine ecosystems were calculated and recommended in the range of 0.012-2.79μg/L and 48.2-1337 ng/g(dry weight),respectively.Overall,the derived PNECs for the studied PAHs in seawater and marine sediment were comparable to those obtained by classical methods.Risk quotient results indicate low ecological risks to ecosystems for ten parent-and alkyl-PAHs in surface seawaters and surface sediments from the Dalian Bay.These findings provide a first insight into the PNECs and ecological risks of alkyl-PAHs,emphasizing the role of the computational toxicology in ecological risk assessments.The use of QSARs has been identified as a valuable tool for preliminarily assessing ecological risks of emerging pollutants,being more predictable of real exposure scenarios for risk assessment purposes.展开更多
Transceiver-free object localization can localize target through using Radio Frequency(RF) technologies without carrying any device, which attracts many researchers' attentions. Most traditional technologies usual...Transceiver-free object localization can localize target through using Radio Frequency(RF) technologies without carrying any device, which attracts many researchers' attentions. Most traditional technologies usually first deploy a number of reference nodes which are able to communicate with each other, then select only some wireless links, whose signals are affected the most by the transceiver-free target, to estimate the target position. However, such traditional technologies adopt an ideal model for the target, the other link information and environment interference behavior are not considered comprehensively. In order to overcome this drawback, we propose a method which is able to precisely estimate the transceiver-free target position. It not only can leverage more link information, but also take environmental interference into account. Two algorithms are proposed in our system, one is Best K-Nearest Neighbor(KNN) algorithm, the other is Support Vector Regression(SVR) algorithm. Our experiments are based on Telos B sensor nodes and performed in different complex lab areas which have many different furniture and equipment. The experiment results show that the average localization error is round 1.1m. Compared with traditional methods, the localization accuracy is increased nearly two times.展开更多
To satisfy the demands for compact,inexpensive terahertz(THz)sources with power of hundreds of watts,a radial sheet beam THz source which does not require an external magnetic field and is driven by a radial pseudospa...To satisfy the demands for compact,inexpensive terahertz(THz)sources with power of hundreds of watts,a radial sheet beam THz source which does not require an external magnetic field and is driven by a radial pseudospark discharge plasma electron gun(PSDP-EGUN)is proposed.Radial design has been used in pseudospark switches,but in this paper the design of a PSDP-EGUN to drive a radial THz source is presented for the first time.Being different from the latest reported axial quasi-rectangular sheet beam THz sources driven by an axial PSDP-EGUN,a new desig n consisti ng of a circular plate-shaped sheet beam that is directly gen erated by the radial PSDP-EGUN is reported.As compared to an axial system,the radial configuration may result in a larger beam current and a larger beam-wave interaction area together with a higher potential of THz output power.Theoretical analysis and pailicle-in-cell simulation have been employed in the design of the radial sheet beam THz source.Output powers in the kilowatt range have been observed in the simulation of this 0.22 THz source.Preliminary experimental results of the radial PSDP-EGUN are also presented.展开更多
Pyruvate dehydrogenase kinase 1(PDK1)phosphorylates the pyruvate dehydroge-nase complex,which inhibits its activity.Inhibiting pyruvate dehydrogenase complex inhibits the tricarboxylic acid cycle and the reprogramming...Pyruvate dehydrogenase kinase 1(PDK1)phosphorylates the pyruvate dehydroge-nase complex,which inhibits its activity.Inhibiting pyruvate dehydrogenase complex inhibits the tricarboxylic acid cycle and the reprogramming of tumor cell metabolism to glycolysis,which plays an important role in tumor progression.This study aims to elucidate how PDK1 pro-motes breast cancer progression.We found that PDK1 was highly expressed in breast cancer tissues,and PDK1 knockdown reduced the proliferation,migration,and tumorigenicity of breast cancer cells and inhibited the HIF-1α(hypoxia-inducible factor 1α)pathway.Further investigation showed that PDK1 promoted the protein stability of HIF-1αby reducing the level of ubiquitination of HIF-1α.The HIF-1αprotein levels were dependent on PDK1 kinase activity.Furthermore,HIF-1αphosphorylation at serine 451 was detected in wild-type breast cancer cells but not in PDK1 knockout breast cancer cells.The phosphorylation of HIF-1αat Ser 451 stabilized its protein levels by inhibiting the interaction of HIF-1αwith von Hippel-Lindau and prolyl hydroxylase domain.We also found that PDK1 enhanced HIF-1αtranscriptional ac-tivity.In summary,PDK1 enhances HIF-1αprotein stability by phosphorylating HIF-1αat Ser451 and promotes HIF-1αtranscriptional activity by enhancing the binding of HIF-1αto P300.PDK1 and HIF-1αform a positive feedback loop to promote breast cancer progression.展开更多
The authors propose and analyze a viral infection model with defectively infected cells and age of the latently infected cells.The existence of steady states is determined by the basic reproduction number of virus.Wit...The authors propose and analyze a viral infection model with defectively infected cells and age of the latently infected cells.The existence of steady states is determined by the basic reproduction number of virus.With the Lyapunov's direct method,they establish a threshold dynamics of the model with the basic reproduction number of virus as the threshold parameter.To achieve it,a novel procedure is proposed.Its novelties are two-folded.On one hand,the coefficients involved in the specific forms of the used Lyapunov functionals for the two feasible steady states are determined by the same set of inequalities.On the other hand,for the infection steady state,a new approach is proposed to check whether the derivative of the Lyapunov functional candidate along solutions is negative(semi-)definite or not.This procedure not only simplifies the analysis but also exhibits the relationship between the two Lyapunov functionals for the two feasible steady states.Moreover,the procedure is expected to be applicable for other similar models.展开更多
Colitis is a common disease of the colon that is very difficult to treat.Probiotic bacteria could be an effective treatment.The probiotic Escherichia coli Nissle 1917(EcN)was engineered to synthesize the ketone body(R...Colitis is a common disease of the colon that is very difficult to treat.Probiotic bacteria could be an effective treatment.The probiotic Escherichia coli Nissle 1917(EcN)was engineered to synthesize the ketone body(R)-3-hydroxybutyrate(3HB)for sustainable production in the gut lumen of mice suffering from colitis.Components of heterologous 3HB synthesis routes were constructed,expressed,optimized,and inserted into the EcN genome,combined with deletions in competitive branch pathways.The genome-engineered EcN produced the highest 3HB level of 0.6 g/L under microaerobic conditions.The live therapeutic was found to colonize the mouse gastrointestinal tract over 14 days,elevating gut 3HB and short-chain-length fatty acid(SCFA)levels 8.7-and 3.1-fold compared to those of wild-type EcN,respectively.The sustainable presence of 3HB in mouse guts promoted the growth of probiotic bacteria,especially Akkermansia spp.,to over 31%from the initial 2%of all the microbiome.As a result,the engineered EcN termed EcNL4 ameliorated colitis induced via dextran sulfate sodium(DSS)in mice.Compared to wild-type EcN or oral administration of 3HB,oral EcNL4 uptake demonstrated better effects on mouse weights,colon lengths,occult blood levels,gut tissue myeloperoxidase activity and proinflammatory cytokine concentrations.Thus,a promising live bacterium was developed to improve colonic microenvironments and further treat colitis.This proof-of-concept design can be employed to treat other diseases of the colon.展开更多
A radio-telemetry recording system is presented which is applied to stimulate specific brain areas and record neuronal ac- tivity in a free-roaming rat. The system consists of two major parts: stationary section and ...A radio-telemetry recording system is presented which is applied to stimulate specific brain areas and record neuronal ac- tivity in a free-roaming rat. The system consists of two major parts: stationary section and mobile section. The stationary section contains a laptop, a Micro Control Unit (MCU), an FM transmitter and a receiver. The mobile section is composed of the headstage and the backpack (which includes the mainboard, FM transmitter, and receiver), which can generate biphasic mi- crocurrent pulses and simultaneously acquire neuronal activity. Prior to performing experiments, electrodes are implanted in the Ventral Posterolateral (VPL) thalamic nucleus, primary motor area (M1) and Medial Forebrain Bundle (MFB) of the rat. The stationary section modulates commands from the laptop for stimulation and demodulates signals for neuronal activity recording. The backpack is strapped on the back of the rat and executes commands from the stationary section, acquires neuronal activity, and transmits the neuronal activity singles of the waking rat to the stationary section. All components in the proposed system are commercially available and are fabricated from Surface Mount Devices (SMD) in order to reduce the size (25 mm×15 mm ×2 mm) and weight (10 g with battery). During actual experiments, the backpack, which is powered by a rechargeable Lithium battery (4 g), can generate biphasic microcurrent pulse stimuli and can also record neuronal activity via the FM link with a maximum transmission rate of 1 kbps for more than one hour within a 200 m range in an open field or in a neighboring chamber. The test results show that the system is able to remotely navigate and control the rat without any prior training, and acquire neuronal activity with desirable features such as small size, low power consumption and high precision when compared with a commercial 4-channel bio-signal acquisition and processing system.展开更多
The optimization of anode materials such as Sn,P and Sn4P3 in terms of capacity and cyclability is crucial to improve the overall performance of sodium-ion batteries.However,the delicate fabrication of these materials...The optimization of anode materials such as Sn,P and Sn4P3 in terms of capacity and cyclability is crucial to improve the overall performance of sodium-ion batteries.However,the delicate fabrication of these materials,including the balanced crystalline/amorphous domains,reasonable particle size and distribution,complementary components exhibiting synergetic reactions,among others,still greatly retards the realization of maximum performance.Herein,a series of Sn/P-based composite materials with a plum pudding configuration were fabricated to achieve controlled crystalline/amorphous structures as well as optimized size and distribution in a carbon framework.By using a facile and low-cost ball milling method,the structural transformation of Sn4P3 into phase-separated crystalline Sn and amorphous P in a carbonaceous framework can be finely controlled,producing a series of binary(Sn4 P3/C),quaternary(Sn4P3/Sn/P/C) and ternary(Sn/P/C) composites.Due to the complementary components,crystalline/amorphous adjustment,crystallite sizes and well-integrated interfaces,the quaternary Sn4P3/Sn/P/C composite showed the best electrochemical performance,with a noticeable long-cycle performance of 382 mA hg-1 and 86% capacity retention for nearly 300 cycles.Different from binary and ternary composites,the discharge of quaternary composite generates no noticeable signals of Na15Sn4 and Na3 P in the ex-situ X-ray diffraction patterns,suggesting the crystallite growth of sodiation products can be depressed.Moreover,Sn4 P3 in the quaternary composite can be partially regenerated in the desodiation reaction,implying the significant short-range interaction and thus better synergetic reactions between Sn and P components.The results demonstrate that the design and organization of crystalline/amorphous structures can serve as an efficient strategy to develop novel electrode materials for sodium ion batteries.展开更多
文摘BACKGROUND Helicobacter pylori(H.pylori)eradication rates have declined with the rise of antibiotic-resistant strains in recent years.Although highly effective with a low prevalence of resistance,standard dose tetracycline is associated with frequent adverse events.The efficacy and safety of low-dose tetracycline as part of tetra-cycline and amoxicillin-containing bismuth quadruple therapy are not well described.AIM To compare the efficacy and safety of low-dose compared to standard dose tetracycline with combined amoxicillin-containing bismuth quadruple therapy in patients with H.pylori infection.METHODS Consecutive patients with H.pylori infection receiving tetracycline,amoxicillin,proton pump inhibitor,and bismuth for 14 days at Sir Run Run Shaw Hospital(1/2022-6/2023)were evaluated.The low-dose tetracycline group received tetracycline 500 mg twice daily(bid)while the standard dose group received 750 mg bid or 500 mg three times daily(tid).Primary endpoints were H.pylori eradication rate and treatment-related adverse events.
基金The authors gratefully acknowledge the financial support from Shanghai Pujiang Program(20PJ1404800)“Scientific and Technical Innovation Action Plan”Basic Research Field of Shanghai Science and Technology Committee(19JC1410500).
文摘The deoxygenation of organic acids, important biomass feedstocks and derivatives, to synthesize hydrocarbon products under mild electrochemical conditions, holds significant importance for the production of carbon-neutral biofuels. There is still limited research on the influential factors of the electrochemical decarboxylation reaction of medium-chain fatty acids. In this study, n-octanoic acid (OA) was chosen as the research subject to investigate the electrochemical decarboxylation behavior of OA on a platinum electrode, focusing on the influence of different alkali metal cations (Li^(+), Na^(+), K^(+)), common anions (SO^(4)^(2−), Cl^(−)), and electrolyte pH. It was found that KOH as an electrolyte exhibited the best performance for OA. Possibly, the larger size of K^(+) increased the alkalinity of the electrode surface, facilitating OA deprotonation. LiOH electrolyte reduced the solubility of OA, thereby inhibiting the decarboxylation reaction. SO^(4)^(2−) exhibited a weak promoting effect on the decarboxylation reaction of OA, while Cl^(−) showed no adverse effect although Cl^(−) may adsorb on the electrode surface. Furthermore, unlike short-chain fatty acids, medium-chain OA can only achieve efficient decarboxylation under alkaline conditions due to its solubility properties. This study provides references and foundations for future efforts to enhance the efficiency of electrochemical decarboxylation synthesis of hydrocarbon biofuels from medium-chain fatty acids.
基金The National Key Research and Development Program of China under contract No.2016YFC1402305the Postdoctoral Research Foundation of China under contract No.2016M601148the Scientific Research Special Fund of Marine Public Welfare Industry under contract No.201305002
文摘Parent and alkylated polycyclic aromatic hydrocarbons(alkyl-PAHs),which are a class of important toxic components of crude oil especially in the marine environment,exhibit adverse effects on aquatic life and potentially pose a human health risk.However,the lack of chronic toxicity data is one of the hindrances for alkylPAHs when assessing their ecological risks.In this study,predicted no-effect concentrations(PNECs)in seawater and marine sediment for ten parent-and alkyl-PAHs were derived by applying species sensitivity distributions(SSDs)and quantitative structure-activity relationships(QSARs).The local area,Dalian Bay,where an oil-spilled accident happened in 2010,was chosen as a case site to assess ecological risks for ten PAHs in surface seawaters and marine sediments.Their PNECs in seawater and sediment for protecting aquatic organisms in marine ecosystems were calculated and recommended in the range of 0.012-2.79μg/L and 48.2-1337 ng/g(dry weight),respectively.Overall,the derived PNECs for the studied PAHs in seawater and marine sediment were comparable to those obtained by classical methods.Risk quotient results indicate low ecological risks to ecosystems for ten parent-and alkyl-PAHs in surface seawaters and surface sediments from the Dalian Bay.These findings provide a first insight into the PNECs and ecological risks of alkyl-PAHs,emphasizing the role of the computational toxicology in ecological risk assessments.The use of QSARs has been identified as a valuable tool for preliminarily assessing ecological risks of emerging pollutants,being more predictable of real exposure scenarios for risk assessment purposes.
基金supported by the National Natural Science Foundation of China (Grant No.61202377, U1301251)National High Technology Joint Research Program of China (Grant No.2015AA015305)+1 种基金Science and Technology Planning Project of Guangdong Province (Grant No.2013B090500055)Guangdong Natural Science Foundation (Grant No.2014A030313553)
文摘Transceiver-free object localization can localize target through using Radio Frequency(RF) technologies without carrying any device, which attracts many researchers' attentions. Most traditional technologies usually first deploy a number of reference nodes which are able to communicate with each other, then select only some wireless links, whose signals are affected the most by the transceiver-free target, to estimate the target position. However, such traditional technologies adopt an ideal model for the target, the other link information and environment interference behavior are not considered comprehensively. In order to overcome this drawback, we propose a method which is able to precisely estimate the transceiver-free target position. It not only can leverage more link information, but also take environmental interference into account. Two algorithms are proposed in our system, one is Best K-Nearest Neighbor(KNN) algorithm, the other is Support Vector Regression(SVR) algorithm. Our experiments are based on Telos B sensor nodes and performed in different complex lab areas which have many different furniture and equipment. The experiment results show that the average localization error is round 1.1m. Compared with traditional methods, the localization accuracy is increased nearly two times.
文摘To satisfy the demands for compact,inexpensive terahertz(THz)sources with power of hundreds of watts,a radial sheet beam THz source which does not require an external magnetic field and is driven by a radial pseudospark discharge plasma electron gun(PSDP-EGUN)is proposed.Radial design has been used in pseudospark switches,but in this paper the design of a PSDP-EGUN to drive a radial THz source is presented for the first time.Being different from the latest reported axial quasi-rectangular sheet beam THz sources driven by an axial PSDP-EGUN,a new desig n consisti ng of a circular plate-shaped sheet beam that is directly gen erated by the radial PSDP-EGUN is reported.As compared to an axial system,the radial configuration may result in a larger beam current and a larger beam-wave interaction area together with a higher potential of THz output power.Theoretical analysis and pailicle-in-cell simulation have been employed in the design of the radial sheet beam THz source.Output powers in the kilowatt range have been observed in the simulation of this 0.22 THz source.Preliminary experimental results of the radial PSDP-EGUN are also presented.
基金supported by grants from the National Natural Science Foundation of China(No.82073255)the Foundation of Chongqing Municipal Education Commission(China)(No.HZ2021006).
文摘Pyruvate dehydrogenase kinase 1(PDK1)phosphorylates the pyruvate dehydroge-nase complex,which inhibits its activity.Inhibiting pyruvate dehydrogenase complex inhibits the tricarboxylic acid cycle and the reprogramming of tumor cell metabolism to glycolysis,which plays an important role in tumor progression.This study aims to elucidate how PDK1 pro-motes breast cancer progression.We found that PDK1 was highly expressed in breast cancer tissues,and PDK1 knockdown reduced the proliferation,migration,and tumorigenicity of breast cancer cells and inhibited the HIF-1α(hypoxia-inducible factor 1α)pathway.Further investigation showed that PDK1 promoted the protein stability of HIF-1αby reducing the level of ubiquitination of HIF-1α.The HIF-1αprotein levels were dependent on PDK1 kinase activity.Furthermore,HIF-1αphosphorylation at serine 451 was detected in wild-type breast cancer cells but not in PDK1 knockout breast cancer cells.The phosphorylation of HIF-1αat Ser 451 stabilized its protein levels by inhibiting the interaction of HIF-1αwith von Hippel-Lindau and prolyl hydroxylase domain.We also found that PDK1 enhanced HIF-1αtranscriptional ac-tivity.In summary,PDK1 enhances HIF-1αprotein stability by phosphorylating HIF-1αat Ser451 and promotes HIF-1αtranscriptional activity by enhancing the binding of HIF-1αto P300.PDK1 and HIF-1αform a positive feedback loop to promote breast cancer progression.
基金supported by the National Natural Science Foundation of China(Nos.11971281,12071268,12071418)the NSERC of Canada(No.RGPIN-2019-05892)+1 种基金the Natural Science Basic Research Program of Shaanxi(Nos.2022JM-029,2023-JC-QN-0090)the Scientific Research Fund of Xi’an Medical University(No.2022JG-53)。
文摘The authors propose and analyze a viral infection model with defectively infected cells and age of the latently infected cells.The existence of steady states is determined by the basic reproduction number of virus.With the Lyapunov's direct method,they establish a threshold dynamics of the model with the basic reproduction number of virus as the threshold parameter.To achieve it,a novel procedure is proposed.Its novelties are two-folded.On one hand,the coefficients involved in the specific forms of the used Lyapunov functionals for the two feasible steady states are determined by the same set of inequalities.On the other hand,for the infection steady state,a new approach is proposed to check whether the derivative of the Lyapunov functional candidate along solutions is negative(semi-)definite or not.This procedure not only simplifies the analysis but also exhibits the relationship between the two Lyapunov functionals for the two feasible steady states.Moreover,the procedure is expected to be applicable for other similar models.
基金This research was financially supported by a grant from the Chunfeng Foundation(2020Z99CFG002)of Tsinghua UniversityOther support includes the National Natural Science Foundation of China(Grant Nos.31870859,21761132013,31771886,and 31971170).
文摘Colitis is a common disease of the colon that is very difficult to treat.Probiotic bacteria could be an effective treatment.The probiotic Escherichia coli Nissle 1917(EcN)was engineered to synthesize the ketone body(R)-3-hydroxybutyrate(3HB)for sustainable production in the gut lumen of mice suffering from colitis.Components of heterologous 3HB synthesis routes were constructed,expressed,optimized,and inserted into the EcN genome,combined with deletions in competitive branch pathways.The genome-engineered EcN produced the highest 3HB level of 0.6 g/L under microaerobic conditions.The live therapeutic was found to colonize the mouse gastrointestinal tract over 14 days,elevating gut 3HB and short-chain-length fatty acid(SCFA)levels 8.7-and 3.1-fold compared to those of wild-type EcN,respectively.The sustainable presence of 3HB in mouse guts promoted the growth of probiotic bacteria,especially Akkermansia spp.,to over 31%from the initial 2%of all the microbiome.As a result,the engineered EcN termed EcNL4 ameliorated colitis induced via dextran sulfate sodium(DSS)in mice.Compared to wild-type EcN or oral administration of 3HB,oral EcNL4 uptake demonstrated better effects on mouse weights,colon lengths,occult blood levels,gut tissue myeloperoxidase activity and proinflammatory cytokine concentrations.Thus,a promising live bacterium was developed to improve colonic microenvironments and further treat colitis.This proof-of-concept design can be employed to treat other diseases of the colon.
文摘A radio-telemetry recording system is presented which is applied to stimulate specific brain areas and record neuronal ac- tivity in a free-roaming rat. The system consists of two major parts: stationary section and mobile section. The stationary section contains a laptop, a Micro Control Unit (MCU), an FM transmitter and a receiver. The mobile section is composed of the headstage and the backpack (which includes the mainboard, FM transmitter, and receiver), which can generate biphasic mi- crocurrent pulses and simultaneously acquire neuronal activity. Prior to performing experiments, electrodes are implanted in the Ventral Posterolateral (VPL) thalamic nucleus, primary motor area (M1) and Medial Forebrain Bundle (MFB) of the rat. The stationary section modulates commands from the laptop for stimulation and demodulates signals for neuronal activity recording. The backpack is strapped on the back of the rat and executes commands from the stationary section, acquires neuronal activity, and transmits the neuronal activity singles of the waking rat to the stationary section. All components in the proposed system are commercially available and are fabricated from Surface Mount Devices (SMD) in order to reduce the size (25 mm×15 mm ×2 mm) and weight (10 g with battery). During actual experiments, the backpack, which is powered by a rechargeable Lithium battery (4 g), can generate biphasic microcurrent pulse stimuli and can also record neuronal activity via the FM link with a maximum transmission rate of 1 kbps for more than one hour within a 200 m range in an open field or in a neighboring chamber. The test results show that the system is able to remotely navigate and control the rat without any prior training, and acquire neuronal activity with desirable features such as small size, low power consumption and high precision when compared with a commercial 4-channel bio-signal acquisition and processing system.
基金This project is supported financially by the National Natural Science Foundation of China(Grants 51622202,21603009 and21875007)the National Key R&D Program of China(Grant No.2018YFB0104302)+1 种基金the Beijing Natural Science Foundation(B)(KZ201910005002)the Guangdong Provincial Science and Technology Program(2016B010114001)。
文摘The optimization of anode materials such as Sn,P and Sn4P3 in terms of capacity and cyclability is crucial to improve the overall performance of sodium-ion batteries.However,the delicate fabrication of these materials,including the balanced crystalline/amorphous domains,reasonable particle size and distribution,complementary components exhibiting synergetic reactions,among others,still greatly retards the realization of maximum performance.Herein,a series of Sn/P-based composite materials with a plum pudding configuration were fabricated to achieve controlled crystalline/amorphous structures as well as optimized size and distribution in a carbon framework.By using a facile and low-cost ball milling method,the structural transformation of Sn4P3 into phase-separated crystalline Sn and amorphous P in a carbonaceous framework can be finely controlled,producing a series of binary(Sn4 P3/C),quaternary(Sn4P3/Sn/P/C) and ternary(Sn/P/C) composites.Due to the complementary components,crystalline/amorphous adjustment,crystallite sizes and well-integrated interfaces,the quaternary Sn4P3/Sn/P/C composite showed the best electrochemical performance,with a noticeable long-cycle performance of 382 mA hg-1 and 86% capacity retention for nearly 300 cycles.Different from binary and ternary composites,the discharge of quaternary composite generates no noticeable signals of Na15Sn4 and Na3 P in the ex-situ X-ray diffraction patterns,suggesting the crystallite growth of sodiation products can be depressed.Moreover,Sn4 P3 in the quaternary composite can be partially regenerated in the desodiation reaction,implying the significant short-range interaction and thus better synergetic reactions between Sn and P components.The results demonstrate that the design and organization of crystalline/amorphous structures can serve as an efficient strategy to develop novel electrode materials for sodium ion batteries.