In a 0.02 mol/L Na_2HPO_4-KH_2PO_4(PBS) buffer solution(pH=6.82), the electrochemical behavior of mitoxantrone was studied by linear-sweep voltammetry and cyclic voltammetry at a Pt/C ion implantation modified microel...In a 0.02 mol/L Na_2HPO_4-KH_2PO_4(PBS) buffer solution(pH=6.82), the electrochemical behavior of mitoxantrone was studied by linear-sweep voltammetry and cyclic voltammetry at a Pt/C ion implantation modified microelectrode. A sensitive reduction peak was observed. The peak potential was \{-0.72 V\}(vs.SCE), the peak current was proportional to the concentration of mitoxantrone within the ranges of 7.0×10 -8—9.0×10 -7 mol/L and 1.0×10 -6—2.4×10 -5 mol/L, with a detection limit of 4.0×10 -8 mol/L. The linear correlation coefficients were 0.9994 and 0.9992, respectively. This method has been applied to the direct determination of mitoxantrone in simulated urine. The recoveries were in the range from 96.2% to 105.9%. The reduction process was a quasi-reversible one with adsorptive characteristics at the Pt/C microelectrode. The electrode reaction rate constant k_s and the electron transfer coefficient α of the system were determined to be 4.5 and 0.65 s -1, respectively. The experiments showed that Pt element had surely been implanted into the surface of the carbon fiber, and the atomic Pt improved the electrocatalytic activity. The Pt/C microelectrode had a good stability and reproducibility.展开更多
Conducting polymers have been studied extensively. An interesting property of the conducting polymer is that the conductivity of some polymers, such as polypyrrolc, polyaniline, poly(3-methylthiophene) etc. , is affec...Conducting polymers have been studied extensively. An interesting property of the conducting polymer is that the conductivity of some polymers, such as polypyrrolc, polyaniline, poly(3-methylthiophene) etc. , is affected by the voltage applied to them. For polypyrrole, the oxidized state is an electronic conductor and the reduced state is essentially insulating. Using this property, one can fabricate the polymer-based electronic devices. Experimental results of Pickun展开更多
The properties of the carbon nanotube powder microelectrodes (denoted CNTPME) are remarkably altered by anodic pretreatment and preadsorption of mediators. It seems that anodic pretreatment leads the long and tangled...The properties of the carbon nanotube powder microelectrodes (denoted CNTPME) are remarkably altered by anodic pretreatment and preadsorption of mediators. It seems that anodic pretreatment leads the long and tangled carbon nanotubes to be partially cut shorter, resulting in more openings as shown by TEM. Besides, the anodic pretreatment may adjust the hydrophobicity of nanotubes to match with that of Os(bpy)32+. As a result, the real surface area and the ability of adsorbing mediator Os(bpy)32+ of the nanotubes are markedly increased so as to effectively catalyze NO2- reduction in acidic solution.展开更多
In this paper, the application of a homemade Nafion and Co(Salen) modified platinum microelec-trode and an ISO-NOPMC microsensor (World Precision Instruments, USA ) to measure nitric oxide in natural seawater is repor...In this paper, the application of a homemade Nafion and Co(Salen) modified platinum microelec-trode and an ISO-NOPMC microsensor (World Precision Instruments, USA ) to measure nitric oxide in natural seawater is reported. These two microelectrodes are suitable for the measurement. In natural seawater, the sensitivity and stability of the ISO-NOPMC microsensor are higher than that of the homemade Nafion and Co(Salen) modified platinum microelectrode.展开更多
Threatened animals respond with appropriate defensive behaviors to survive.It has been accepted that midbrain periaqueductal gray(PAG)plays an essential role in the circuitry system and organizes defensive behavioral ...Threatened animals respond with appropriate defensive behaviors to survive.It has been accepted that midbrain periaqueductal gray(PAG)plays an essential role in the circuitry system and organizes defensive behavioral responses.However,the role and correlation of different PAG subregions in the expression of different defensive behaviors remain largely unexplored.Here,we designed and manufactured a microelectrode array(MEA)to simultaneously detect the activities of dPAG and vPAG neurons in freely behaving rats.To improve the detection performance of the MEAs,PtNP/PEDOT:PSS nanocomposites were modified onto the MEAs.Subsequently,the predator odor was used to induce the rat’s innate fear,and the changes and information transmission in neuronal activities were detected in the dPAG and vPAG.Our results showed that the dPAG and vPAG participated in innate fear,but the activation degree was distinct in different defense behaviors.During flight,neuronal responses were stronger and earlier in the dPAG than the vPAG,while vPAG neurons responded more strongly during freezing.By applying high-performance MEA,it was revealed that neural information spread from the activated dPAG to the weakly activated vPAG.Our research also revealed that dPAG and vPAG neurons exhibited different defensive discharge characteristics,and dPAG neurons participated in the regulation of defense responses with burst-firing patterns.The slow activation and continuous firing of vPAG neurons cooresponded with the regulation of long-term freezing responses.The results demonstrated the important role of PAG neuronal activities in controlling different aspects of defensive behaviors and provided novel insights for investigating defense from the electrophysiological perspective.展开更多
The adsorption capacities of new humic acids isolated from Yakouren forest （YHA） and Sahara （Tamenrasset： THA） soils （Algeria） and commercial humic acid （PFHA） on polyaniline emeraldine base （PEB） were stud...The adsorption capacities of new humic acids isolated from Yakouren forest （YHA） and Sahara （Tamenrasset： THA） soils （Algeria） and commercial humic acid （PFHA） on polyaniline emeraldine base （PEB） were studied at pH 6.6. Also the adsorption of heavy metals such as Cd 2＋ , Zn 2＋ and Ni 2＋ on humic acid-polyaniline systems （HA-PEB） was investigated at the same conditions. HA-PEB compounds were characterized by scanning electron microscopy （SEM）, infrared spectrometry and cavity microelectrode. In addition, batch adsorption and cavity microelectrode were used in the adsorption study of Cd 2＋ , Zn 2＋ and Ni 2＋ on HA-PEB. To develop biocaptors of polluting metals using a cavity microelectrode modified by HA-PEB systems, the adsorption kinetic and adsorption capacity were investigated. The SEM analysis showed that the presence of humic acid affected the PEB surface and caused the formation of a granular morphology. The maximum adsorption capacities （q max ） of PFHA, THA and YHA determined by adsorption isotherms were 91.31, 132.1 and 151.0 mg/g, respectively. Batch adsorption results showed that q max of Cd 2＋ , Zn 2＋ and Ni 2＋ on HA-PEB followed the order： THA-PEB YHA-PEB PFHA-PEB. The voltammograms obtained with HA-PEB modified cavity microelectrode showed the appearance of new redox couples reflecting the adsorption of HA on PEB. Metal-humic acid-polyaniline voltammograms were characterized by appearance of oxidation-reduction couples or reduction wave corresponding to metal. Finally, the result may be exploited to develop a biocaptor based on the cavity microelectrode amended by THA-PEB and YHA-PEB.展开更多
文摘In a 0.02 mol/L Na_2HPO_4-KH_2PO_4(PBS) buffer solution(pH=6.82), the electrochemical behavior of mitoxantrone was studied by linear-sweep voltammetry and cyclic voltammetry at a Pt/C ion implantation modified microelectrode. A sensitive reduction peak was observed. The peak potential was \{-0.72 V\}(vs.SCE), the peak current was proportional to the concentration of mitoxantrone within the ranges of 7.0×10 -8—9.0×10 -7 mol/L and 1.0×10 -6—2.4×10 -5 mol/L, with a detection limit of 4.0×10 -8 mol/L. The linear correlation coefficients were 0.9994 and 0.9992, respectively. This method has been applied to the direct determination of mitoxantrone in simulated urine. The recoveries were in the range from 96.2% to 105.9%. The reduction process was a quasi-reversible one with adsorptive characteristics at the Pt/C microelectrode. The electrode reaction rate constant k_s and the electron transfer coefficient α of the system were determined to be 4.5 and 0.65 s -1, respectively. The experiments showed that Pt element had surely been implanted into the surface of the carbon fiber, and the atomic Pt improved the electrocatalytic activity. The Pt/C microelectrode had a good stability and reproducibility.
基金Supported by the National Natural Science Foundation of China
文摘Conducting polymers have been studied extensively. An interesting property of the conducting polymer is that the conductivity of some polymers, such as polypyrrolc, polyaniline, poly(3-methylthiophene) etc. , is affected by the voltage applied to them. For polypyrrole, the oxidized state is an electronic conductor and the reduced state is essentially insulating. Using this property, one can fabricate the polymer-based electronic devices. Experimental results of Pickun
基金The authors are grateful to the National Natural Science Foundation of China for financial support for this work.
文摘The properties of the carbon nanotube powder microelectrodes (denoted CNTPME) are remarkably altered by anodic pretreatment and preadsorption of mediators. It seems that anodic pretreatment leads the long and tangled carbon nanotubes to be partially cut shorter, resulting in more openings as shown by TEM. Besides, the anodic pretreatment may adjust the hydrophobicity of nanotubes to match with that of Os(bpy)32+. As a result, the real surface area and the ability of adsorbing mediator Os(bpy)32+ of the nanotubes are markedly increased so as to effectively catalyze NO2- reduction in acidic solution.
基金Supported by the NSFC (No. 40076020) National Basic Research Priority Program (973) (No.2001CB409700) and the research fund for the doctoral program for higher education.
文摘In this paper, the application of a homemade Nafion and Co(Salen) modified platinum microelec-trode and an ISO-NOPMC microsensor (World Precision Instruments, USA ) to measure nitric oxide in natural seawater is reported. These two microelectrodes are suitable for the measurement. In natural seawater, the sensitivity and stability of the ISO-NOPMC microsensor are higher than that of the homemade Nafion and Co(Salen) modified platinum microelectrode.
基金This work was sponsored by the National Natural Science Foundation of China(T2293731,L2224042,61988102,62121003,61960206012,62171434,61971400,61975206,and 61973292)the Frontier Interdisciplinary Project of the Chinese Academy of Sciences(XK2022XXC003)+2 种基金STI 2030-Major Projects 2021ZD0201600the National Key R&D Program of China(2022YFC2402501)the Scientific Instrument Developing Project of the Chinese Academy of Sciences(GJJSTD20210004).
文摘Threatened animals respond with appropriate defensive behaviors to survive.It has been accepted that midbrain periaqueductal gray(PAG)plays an essential role in the circuitry system and organizes defensive behavioral responses.However,the role and correlation of different PAG subregions in the expression of different defensive behaviors remain largely unexplored.Here,we designed and manufactured a microelectrode array(MEA)to simultaneously detect the activities of dPAG and vPAG neurons in freely behaving rats.To improve the detection performance of the MEAs,PtNP/PEDOT:PSS nanocomposites were modified onto the MEAs.Subsequently,the predator odor was used to induce the rat’s innate fear,and the changes and information transmission in neuronal activities were detected in the dPAG and vPAG.Our results showed that the dPAG and vPAG participated in innate fear,but the activation degree was distinct in different defense behaviors.During flight,neuronal responses were stronger and earlier in the dPAG than the vPAG,while vPAG neurons responded more strongly during freezing.By applying high-performance MEA,it was revealed that neural information spread from the activated dPAG to the weakly activated vPAG.Our research also revealed that dPAG and vPAG neurons exhibited different defensive discharge characteristics,and dPAG neurons participated in the regulation of defense responses with burst-firing patterns.The slow activation and continuous firing of vPAG neurons cooresponded with the regulation of long-term freezing responses.The results demonstrated the important role of PAG neuronal activities in controlling different aspects of defensive behaviors and provided novel insights for investigating defense from the electrophysiological perspective.
文摘The adsorption capacities of new humic acids isolated from Yakouren forest （YHA） and Sahara （Tamenrasset： THA） soils （Algeria） and commercial humic acid （PFHA） on polyaniline emeraldine base （PEB） were studied at pH 6.6. Also the adsorption of heavy metals such as Cd 2＋ , Zn 2＋ and Ni 2＋ on humic acid-polyaniline systems （HA-PEB） was investigated at the same conditions. HA-PEB compounds were characterized by scanning electron microscopy （SEM）, infrared spectrometry and cavity microelectrode. In addition, batch adsorption and cavity microelectrode were used in the adsorption study of Cd 2＋ , Zn 2＋ and Ni 2＋ on HA-PEB. To develop biocaptors of polluting metals using a cavity microelectrode modified by HA-PEB systems, the adsorption kinetic and adsorption capacity were investigated. The SEM analysis showed that the presence of humic acid affected the PEB surface and caused the formation of a granular morphology. The maximum adsorption capacities （q max ） of PFHA, THA and YHA determined by adsorption isotherms were 91.31, 132.1 and 151.0 mg/g, respectively. Batch adsorption results showed that q max of Cd 2＋ , Zn 2＋ and Ni 2＋ on HA-PEB followed the order： THA-PEB YHA-PEB PFHA-PEB. The voltammograms obtained with HA-PEB modified cavity microelectrode showed the appearance of new redox couples reflecting the adsorption of HA on PEB. Metal-humic acid-polyaniline voltammograms were characterized by appearance of oxidation-reduction couples or reduction wave corresponding to metal. Finally, the result may be exploited to develop a biocaptor based on the cavity microelectrode amended by THA-PEB and YHA-PEB.
