Effects of temperature, glucose and inorganic nitrogen inputs on carbon mineralization in a Tibetan alpine meadow soil

High levels of available nitrogen (N) and carbon (C) have the potential to increase soil N and C mineralization We hypothesized that with an external labile C or N supply alpine meadow soil will have a significantly higher C mineralization potential and that temperature sensitivity of C mineralization will increase To test the hypotheses an incubation experiment was conducted with two doses of N or C supply at temperature of 5 15 and 25 C Results showed external N supply had no significant effect on CO2 emission However external C supply increased CO2 emission Temperature coefficient (Q(10)) ranged from 113 to 1 29 Significantly higher values were measured with C than with N addition and control treatment Temperature dependence of C mineralization was well-represented by exponential functions Under the control CO2 efflux rate was 425 g CO2-Cm-2 year(-1) comparable to the in situ measurement of 422 g CO2-Cm-2 year(-1) We demonstrated if N is disregarded microbial decomposition is primarily limited by lack of labile C It is predicted that labile C supply would further increase CO2 efflux from the alpine meadow soil (C) 2010 Elsevier Masson SAS All rights reserved

Magnet-assisted assembly of 1-dimensional hollow PtCo nanomaterials on an electrode surface

In this work, rapid and controllable confinement of one-dimensional (1D) hollow PtCo nanomaterials on an indium tin oxide (ITO) electrode surface was simply realized via magnetic attraction. The successful assembly was verified by scanning electron microscopy (SEM) and cyclic voltammetry, which showed that a longer exposure time of the electrode to the suspension of these 1D hollow nanomaterials (magnetic suspension) led to a larger amount of attached 1D hollow PtCo nanomaterials.

The characteristics of highly ordered mesoporous carbons as electrode material for electrochemical sensing as compared with carbon nanotubes

In this paper, the unique properties of highly ordered mesoporous carbons modified glassy carbon electrode (OMCs/GE) are illustrated from comparison with carbon nanotubes modified glassy carbon electrode (CNTs/GE) for the electrochemical sensing applications.

Macroporous Pt modified glassy carbon electrode: preparation and electrocatalytic activity for methanol oxidation

Three-dimensional (3D) macroporous Pt (MPPt) with highly open porous walls has been successfully synthesized using the hydrogen bubble dynamic template synthesis and galvanic replacement reaction. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and electrochemical methods were adopted to characterize their structures and properties.

Hydrogen peroxide biosensor based on horseradish peroxidase-Au nanoparticles at viologen grafted glassy carbon electrode

A novel hydrogen peroxide biosensor was fabricated that is based on horseradish peroxidase-Au nanoparticles immobilized on a viologen-modified glassy carbon electrode (GCE) by amino cation radical oxidation in basic solution. The immobilized BAPV acts as a mediator and a covalent linker between GCE and the Au nanoparticles. The biosensor exhibited fast response, good reproducibility, and long-term stability.

Platinum-coated gold nanoporous film surface: Electrodeposition and enhanced electrocatalytic activity for methanol oxidation

This report describes the preparation of Pt-nanoparticle-coated gold-nanoporous film (PGNF) on a gold substrate via a simple "green" approach. The gold electrode that has been anodized under a high potential of 5 V is reduced by freshly prepared ascorbic acid (AA) solution to obtain gold nanoporous film electrode. Then the Pt nanoparticle is grown on the electrode by cyclic voltammetry (CV).

Properties of poly(sodium 4-styrenesulfonate)-ionic liquid composite film and its application in the determination of trace metals combined with bismuth film electrode

A new kind of bismuth film modified electrode to sensitively detect trace metal ions based on incorporating highly conductive ionic liquids 1-butyl-3-methyl-imidazolium hexafluorophosphate (BMIMPF6) in solid matrices at glassy carbon (GC) was investigated. Poly(sodium 4-styrenesulfonate) (PSS), silica, and Nafion were selected as the solid matrices. The electrochemical properties of the mixed films modified GC were evaluated. The electron transfer rate of Fe(CN)(6)(4-)/Fe(CN)(6)(3-) can be effectively improved at the PSS-BMIMPF6 modified GC.

Fe3O4 magnetic nanoparticles as peroxidase mimetics and their applications in H2O2 and glucose detection

Artificial enzyme mimetics are a current research interest because natural enzymes bear some serious disadvantages, such as their catalytic activity can be easily inhibited and they can be digested by proteases. A very recently study reported by Yan et al. has proven that Fe3O4 magnetic nanoparticles (MNPs) exhibit an intrinsic enzyme mimetic activity similar to that found in natural peroxidases, though MNPs are usually thought to be biological and chemical inert (Gao, L. Z.; Zhuang, J.; Nie, L.; Zhang, J. B.; Zhang, Y.; Gu, N.; Wang, T. H.; Feng, J.; Yang, D. L.; Perrett, S.; Yan, X. Y. Nat. Nanotechnol. 2007, 2, 577-583).

Simultaneous electrochemical determination of dopamine, uric acid and ascorbic acid using palladium nanoparticle-loaded carbon nanofibers modified electrode

Palladium nanoparticle-loaded carbon nanofibers (Pd/CNFs) were prepared by electrospinning and subsequent thermal treatment processes. Pd/CNFs modified carbon paste electrode (Pd/CNF-CPE) displayed excellent electrochemical catalytic activities towards dopamine (DA), uric acid (UA) and ascorbic acid (AA). The oxidation overpotentials of DA, UA and AA were decreased significantly compared with those obtained at the bare CPE. Differential pulse voltammetry was used for the simultaneous determination of DA, UA and AA in their ternary mixture.

Simultaneous determination of dopamine, ascorbic acid and uric acid with electrospun carbon nanofibers modified electrode

A novel carbon-nanofiber-modified carbon-paste electrode (CNF-CPE) was employed for the simultaneous determination of dopamine (DA), ascorbic acid (AA) and uric acid (UA) with good selectivity and high sensitivity. The CNFs were prepared by combination of electrospinning technique with thermal treatment method and were used without any pretreatment. In application to determination of DA, AA and UA in the ternary mixture, the pristine CNF-CPE exhibited well-separated differential pulse voltammetric peaks with high catalytic current. Low detection limits of 0.04 mu M, 2 mu M and 0.2 mu M for DA, AA and UA were obtained, with the linear calibration curves over the concentration range 0.04-5.6 mu M, 2-64 mu M and 0.8-16.8 mu M, respectively.

A electrochemiluminescence aptasensor for detection of thrombin incorporating the capture aptamer labeled with gold nanoparticles immobilized onto the thio-silanized ITO electrode

A novel electrochemiluminescence (ECL) aptasensor was proposed for sensitive and cost-effective detection of the target thrombin adopted an aptamer-based sandwich format. To detect thrombin, capture aptamers; labeled with gold nanoparticles (AuNPs) were first immobilized onto the thio-silanized ITO electrode surface through strong Au-S bonds. After catching the target thrombin, signal aptamers; tagged with ECL labels were attached to the assembled electrode surface. As a result, an AuNPs-capture-aptamer/thrombin/ECL-tagged signal-aptamer sandwich type was formed.

Determination of concentrated hydrogen peroxide at single-walled carbon nanohorn paste electrode

Single-walled carbon nanohorn (SWCNH) paste electrode was used for amperometric determination of concentrated hydrogen peroxide, and was compared with other carbon electrodes. The calibration plots are linear from 0.5 to 100 mM at activated SWCNH paste electrode and edge plane graphite (EPG) electrode. In contrast, the calibration plots are linear only at concentrations lower than 45 mM at graphite paste electrode, multi-walled carbon nanotube paste electrode, and glassy carbon electrode.

The mechanism of formic acid electro oxidation on iron tetrasulfophthalocyanine-modified platinum electrode

The mechanism of formic acid electrooxidation on iron tetrasulfophthalocyanine (FeTSPc) modified Pt electrode was investigated with electrochemical methods. It was found that a "third-body" effect of FeTSPc on Pt electrode predominates during the electrooxidation process based on unusual electrochemical results. The modification leads formic acid electrooxidation to take place through a desired direct pathway, in which the mechanism is proposed to be the gradual dehydrogenation of formic acid and the reaction of formate with hydroxyl species.

The direct electrochemistry behavior of Cyt c on the modified glassy carbon electrode by SBA-15 with a high-redox potential

It is discovered that SBA-15 (santa barbara amorphous) can provide the favorable microenvironments and optimal direct electron-transfer tunnels (DETT) of immobilizing cytochrome c (Cyt c) by the preferred orientation on it. A high-redox potential (254 mV vs. Ag/AgCl) was obtained on glassy carbon (GC) electrode modified by immobilizing Cyt c on rod-like SBA-15. With ultraviolet-visible (UV-vis), circular dichroism (CD), FTIR and cyclic voltammetry, it was demonstrated that immobilization made Cyt c exhibits stable and ideal electrochemical characteristics while the biological activity of immobilized Cyt c is retained as usual.