The conversion of acetone derived from biomass to isobutene has attracted extensive attentions.In comparison with Brønsted acidic catalyst,Lewis acidic catalyst could exhibit a better catalytic performance with a...The conversion of acetone derived from biomass to isobutene has attracted extensive attentions.In comparison with Brønsted acidic catalyst,Lewis acidic catalyst could exhibit a better catalytic performance with a higher isobutene selectivity.However,the catalyst stability remains a key problem for the long-running acetone conversion and the reasons for catalyst deactivation are poorly understood up to now.Herein,the deactivation mechanism of Lewis acidic Y/Beta catalyst during the acetone to isobutene conversion was investigated by various characterization techniques,including acetone-temperature-programmed surface reaction,gas chromatography-mass spectrometry,in situ ultraviolet-visible,and ^(13)C cross polarization magic angle spinning nuclear magnetic resonance spectroscopy.A successive aldol condensation and cyclization were observed as the main side-reactions during the acetone conversion at Lewis acidic Y sites.In comparison with the low reaction temperature,a rapid formation and accumulation of the larger cyclic unsaturated aldehydes/ketones and aromatics could be observed,and which could strongly adsorb on the Lewis acidic sites,and thus cause the catalyst deactivation eventually.After a simple calcination,the coke deposits could be easily removed and the catalytic activity could be well restored.展开更多
Objectives This study aimed to investigate the therapeutic effects of Suan Zao Ren(Semen Ziziphi Spinosae,SZS)extract on insomnia induced by p-chlorophenylalanine(PCPA)in rats and its influence on the thioredoxin-inte...Objectives This study aimed to investigate the therapeutic effects of Suan Zao Ren(Semen Ziziphi Spinosae,SZS)extract on insomnia induced by p-chlorophenylalanine(PCPA)in rats and its influence on the thioredoxin-interacting protein(TXNIP)/nucleotide-binding domain Leucine-rich repeat and pyrin domain-containing receptor 3(NLRP3)inflammasome pathway,and to preliminarily explore themechanism by which SZS extract improves insomnia.Methods Fifty male Sprague–Dawley(SD)rats were used,with 8 rats in the blank group and 42 rats in the modeling group.The modeling group was induced by intraperitoneal injection of PCPA at a dose of 500mg·kg^(-1) for six consecutive days,with daily cage exchange.After 6 days,40 successfully modeled rats were randomly divided into five groups:themodel group(equal volume of distilled water),the positive group(0.75 mg·kg^(-1)),and low-,medium-,and high-dose SZS extract groups(1.5,3,and 6 g·kg^(-1),respectively),with 8 rats in each group.Treatments were administered for seven consecutive days.Enzyme-linked immunosorbent assay was used to measure levels of 5-hydroxytryptamine(5-HT)and gamma-aminobutyric acid(GABA)in the rat cerebral cortex.The thiobarbituric acid(TBA)method was used to determine malondialdehyde(MDA)levels,and the hydroxylamine method was used to determine superoxide dismutase(SOD)levels.The 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)method was used to measure total antioxidant capacity(TAOC)in the cerebral cortex.Pathological changes in the cerebral cortex were observed,and Western blot was used to detect the protein expressions of TXNIP,NLRP3,apoptosis-associated speck-like protein containing a Caspase activation and recruitment domain(CARD),and cysteine–aspartate-specific protease 1(Caspase-1)in the cerebral cortex.Results Compared with the blank group,the model group showed a significantly prolonged sleep latency(p<0.001)and a significantly shortened sleep duration(p<0.001).There were no changes in serum MDA and SOD levels.MDA levels in the cerebral cortex were significantly increased(p<0.001),while SOD and TAOC levels were significantly decreased(p<0.001).The 5-HT level was increased(p<0.05),and the GABA level was significantly decreased(p<0.001).SZS extract improved these conditions to varying degrees.Light microscopy showed no significant changes in cortical neurons but transmission electron microscopy revealed intact mitochondrial structures in the blank group,while the model group showed swollen and unclear mitochondria with reduced organelles.After 7 days of treatment,these conditions improved in the SZS extract groups.Compared with the blank group,the expressions of the four proteins in the model group were increased,and the expressions of these proteins were decreased in the SZS extract groups compared with the model group.Conclusion SZS extract may exert an antioxidant effect to treat insomnia by downregulating the expression of TXNIP/NLRP3 proteins and regulating oxidative stress levels in the cerebral cortex.展开更多
A multiplexer with a low-distortion high-bandwidth analog switch is presented. The gate-to-source voltage of the switch is set by the combined on-voltage of a pMOS and an nMOS,and the difference between its gate-sourc...A multiplexer with a low-distortion high-bandwidth analog switch is presented. The gate-to-source voltage of the switch is set by the combined on-voltage of a pMOS and an nMOS,and the difference between its gate-source voltage and the threshold voltage （VGST） is guaranteed to be constant with input variation. Thus, the body effect is nearly canceled. Implemented in a TSMC 0.18μm CMOS process, results from HSPICE simulation show that the VGST is nearly constant with an input range from 0.3 to 1.7V,and the - 3dB bandwidth is larger than 10GHz;the SFDR （spurious free dynamic range） of the output is 67. lldB with 1GHz input frequency; the turn-on time is 2.98ns,and the turn-off time is 1.35ns, which indicates a break-before-make action of the multiplexer. The proposed structure can be applied to high speed signal transmission.展开更多
This paper discusses the primary causes from the point of synergistic effects to improve power system vulnerability in the power system planning and safety operation. Based on the vulnerability conception in the compl...This paper discusses the primary causes from the point of synergistic effects to improve power system vulnerability in the power system planning and safety operation. Based on the vulnerability conception in the complex network theory the vulnerability of the power system can be evaluated by the minimum load loss rate when considering power supply ability.Consequently according to the synergistic effect theory the critical line of the power system is defined by its influence on failure set vulnerability in N-k contingencies.The cascading failure modes are proposed based on the criterion whether the acceptable load curtailment level is below a preset value.Significant conclusions are revealed by results of IEEE 39 case analysis weak points of power networks and heavy load condition are the main causes of large-scale cascading failures damaging synergistic effects can result in partial failure developed into large-scale cascading failures vulnerable lines of power systems can directly lead the partial failure to deteriorate into a large blackout while less vulnerable lines can cause a large-scale cascading failure.展开更多
文摘The conversion of acetone derived from biomass to isobutene has attracted extensive attentions.In comparison with Brønsted acidic catalyst,Lewis acidic catalyst could exhibit a better catalytic performance with a higher isobutene selectivity.However,the catalyst stability remains a key problem for the long-running acetone conversion and the reasons for catalyst deactivation are poorly understood up to now.Herein,the deactivation mechanism of Lewis acidic Y/Beta catalyst during the acetone to isobutene conversion was investigated by various characterization techniques,including acetone-temperature-programmed surface reaction,gas chromatography-mass spectrometry,in situ ultraviolet-visible,and ^(13)C cross polarization magic angle spinning nuclear magnetic resonance spectroscopy.A successive aldol condensation and cyclization were observed as the main side-reactions during the acetone conversion at Lewis acidic Y sites.In comparison with the low reaction temperature,a rapid formation and accumulation of the larger cyclic unsaturated aldehydes/ketones and aromatics could be observed,and which could strongly adsorb on the Lewis acidic sites,and thus cause the catalyst deactivation eventually.After a simple calcination,the coke deposits could be easily removed and the catalytic activity could be well restored.
基金Research on the Mechanism of Suan Zao Ren’s(SZS)Hypnotic Effect Based on TXNIP/NLRP3 Signaling Pathway(2023-ZXFZJJ-JW-071).
文摘Objectives This study aimed to investigate the therapeutic effects of Suan Zao Ren(Semen Ziziphi Spinosae,SZS)extract on insomnia induced by p-chlorophenylalanine(PCPA)in rats and its influence on the thioredoxin-interacting protein(TXNIP)/nucleotide-binding domain Leucine-rich repeat and pyrin domain-containing receptor 3(NLRP3)inflammasome pathway,and to preliminarily explore themechanism by which SZS extract improves insomnia.Methods Fifty male Sprague–Dawley(SD)rats were used,with 8 rats in the blank group and 42 rats in the modeling group.The modeling group was induced by intraperitoneal injection of PCPA at a dose of 500mg·kg^(-1) for six consecutive days,with daily cage exchange.After 6 days,40 successfully modeled rats were randomly divided into five groups:themodel group(equal volume of distilled water),the positive group(0.75 mg·kg^(-1)),and low-,medium-,and high-dose SZS extract groups(1.5,3,and 6 g·kg^(-1),respectively),with 8 rats in each group.Treatments were administered for seven consecutive days.Enzyme-linked immunosorbent assay was used to measure levels of 5-hydroxytryptamine(5-HT)and gamma-aminobutyric acid(GABA)in the rat cerebral cortex.The thiobarbituric acid(TBA)method was used to determine malondialdehyde(MDA)levels,and the hydroxylamine method was used to determine superoxide dismutase(SOD)levels.The 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)method was used to measure total antioxidant capacity(TAOC)in the cerebral cortex.Pathological changes in the cerebral cortex were observed,and Western blot was used to detect the protein expressions of TXNIP,NLRP3,apoptosis-associated speck-like protein containing a Caspase activation and recruitment domain(CARD),and cysteine–aspartate-specific protease 1(Caspase-1)in the cerebral cortex.Results Compared with the blank group,the model group showed a significantly prolonged sleep latency(p<0.001)and a significantly shortened sleep duration(p<0.001).There were no changes in serum MDA and SOD levels.MDA levels in the cerebral cortex were significantly increased(p<0.001),while SOD and TAOC levels were significantly decreased(p<0.001).The 5-HT level was increased(p<0.05),and the GABA level was significantly decreased(p<0.001).SZS extract improved these conditions to varying degrees.Light microscopy showed no significant changes in cortical neurons but transmission electron microscopy revealed intact mitochondrial structures in the blank group,while the model group showed swollen and unclear mitochondria with reduced organelles.After 7 days of treatment,these conditions improved in the SZS extract groups.Compared with the blank group,the expressions of the four proteins in the model group were increased,and the expressions of these proteins were decreased in the SZS extract groups compared with the model group.Conclusion SZS extract may exert an antioxidant effect to treat insomnia by downregulating the expression of TXNIP/NLRP3 proteins and regulating oxidative stress levels in the cerebral cortex.
文摘A multiplexer with a low-distortion high-bandwidth analog switch is presented. The gate-to-source voltage of the switch is set by the combined on-voltage of a pMOS and an nMOS,and the difference between its gate-source voltage and the threshold voltage （VGST） is guaranteed to be constant with input variation. Thus, the body effect is nearly canceled. Implemented in a TSMC 0.18μm CMOS process, results from HSPICE simulation show that the VGST is nearly constant with an input range from 0.3 to 1.7V,and the - 3dB bandwidth is larger than 10GHz;the SFDR （spurious free dynamic range） of the output is 67. lldB with 1GHz input frequency; the turn-on time is 2.98ns,and the turn-off time is 1.35ns, which indicates a break-before-make action of the multiplexer. The proposed structure can be applied to high speed signal transmission.
基金The National Natural Science Foundation of China(No.51277028)
文摘This paper discusses the primary causes from the point of synergistic effects to improve power system vulnerability in the power system planning and safety operation. Based on the vulnerability conception in the complex network theory the vulnerability of the power system can be evaluated by the minimum load loss rate when considering power supply ability.Consequently according to the synergistic effect theory the critical line of the power system is defined by its influence on failure set vulnerability in N-k contingencies.The cascading failure modes are proposed based on the criterion whether the acceptable load curtailment level is below a preset value.Significant conclusions are revealed by results of IEEE 39 case analysis weak points of power networks and heavy load condition are the main causes of large-scale cascading failures damaging synergistic effects can result in partial failure developed into large-scale cascading failures vulnerable lines of power systems can directly lead the partial failure to deteriorate into a large blackout while less vulnerable lines can cause a large-scale cascading failure.
