Dominance of felsic continental crust on Earth after 3 billion years ago is recorded by vanadium isotopes.

The transition from mafic to felsic upper continental crust (UCC) is crucial to habitability of Earth, and may be related to the onset of plate tectonics. Thus, defining when this crustal transition occurred has great significance for the evolution of Earth and its inhabitants. We demonstrate that V isotope ratios (reported as δV) provide insights into this transition because they correlate positively with SiO and negatively with MgO contents during igneous differentiation in both subduction zones and intraplate settings.

Phosphorus modification of cobalt-iron nanoparticles embedded in a nitrogen-doped carbon network for oxygen reduction reaction.

For the electrochemical reduction of oxygen the development of heteroatom-doped carbon-based transition metal catalysts has become a recognized strategy to replace traditional noble metal catalysts. In this work a catalyst consisting of CoFe nanoparticles encapsulated in N-doped carbon-based materials (NC) supported by carbon nanotubes (CNTs), FeCo@NC/CNTs, was modified treatment with a phosphate salt to synthesize a P-FeCo@NC/CNTs catalyst. The P-FeCo@NC/CNTs exhibits with 5.

An electrochemical daunorubicin sensor based on the use of platinum nanoparticles loaded onto a nanocomposite prepared from nitrogen decorated reduced graphene oxide and single-walled carbon nanotubes.

A glassy carbon electrode (GCE) was modified with a nanocomposite prepared from nitrogen-doped reduced graphene oxide (N-rGO) and single walled carbon nanotubes (SWCNTs), and then loaded with platinum nanoparticles (Pt NPs) to obtain a voltammetric sensor for daunorubicin (DNR). Reductive doping of GO and the crystallization of the Pt NPs were carried out in a one-step hydrothermal process. The modified electrode was characterized by cyclic voltammetry and differential pulse voltammetry.

Voltammetric simultaneous determination of catechol and hydroquinone using a glassy carbon electrode modified with a ternary hybrid material composed of reduced graphene oxide, magnetite nanoparticles and gold nanoparticles.

An electrochemical sensor is described for the simultaneous determination of the pollutants catechol (CC) and hydroquinone (HQ). A glassy carbon electrode (GCE) was modified with reduced graphene oxide, FeO and gold nanoparticles and then showed a pair of well-defined voltammetric peaks for CC and HQ. Its oxidation peak potentials (located at 0.

Carbon nanospheres with dual-color emission and their application in ratiometric pyrophosphate sensing.

Herein, we employ pH-dependent solubility equilibrium to develop the one-pot aqueous synthesis of dual-color emission fluorescent carbon nanosphere (DFCSs) with novel physicochemical properties. Unexpectedly, some of the DFCSs have a regular nanosphere shape, containing uniform carbon dots (∼20 nm) on their surface. This may be attributed to the change in the surface composition of the carbon nanospheres under the strong alkaline conditions (pH 13), which results in dual-wavelength emission by single-wavelength excitation.

Photoluminescent coral-like carbon-branched polymers as nanoprobe for fluorometric determination of captopril.

The authors describe the synthesis of fluorescent coral-like carbon nano-branched polymers (PCNBPs) co-doped with nitrogen and phosphorus. Uric acid and phosphoric acid act as nitrogen and phosphorus sources, respectively. The PCNBPs have a coral-like branched structure, are cross-connected, and < 20 nm in skeleton diameter.

Multiplexed ratiometric photoluminescent detection of pyrophosphate using anisotropic boron-doped nitrogen-rich carbon rugby ball-like nanodots.

The shape of nanoparticles is decisive for their intrinsic physicochemical properties, as well as for the anisotropic behavior of individual particles in many instances. Herein, boron-doped nitrogen-rich carbon rugby ball-like nanodots (BNCRDs) have been synthesized by a heterophase polymerization route at a vital mass ratio of phenylboronic acid and uric acid in the precursor solution. Unexpectedly, the as-prepared BNCRDs showed stable dispersions of ellipsoidal carbonaceous polymer nanodots (rugby ball-like structures that are approximately 150 nm in length) as novel carbon dot derivatives.

BiOCO Nanosheets as Electrocatalysts for Selective Reduction of CO to Formate at Low Overpotential.

Electrochemical reduction of carbon dioxide (CO) to formate is energetically inefficient because a high overpotential (>1.0 V) is required for most traditional catalysts. In this work, BiOCO (BOC) nanosheets were synthesized as electrocatalysts of CO reduction for the first time.

Clinical value of polymerase chain reaction in the diagnosis of joint tuberculosis by detecting the DNA of Mycobacterium tuberculosis.

Objective: To assess the clinical value of polymerase chain reaction (PCR) in the diagnosis and differential diagnosis of joint tuberculosis (TB).

Methods: PCR was used blindly to detect the DNA of Mycobacterium tuberculosis (M.TB) in five specimens of M.