Electrochemical Detection of Ammonia in Water Using NiCu Carbonate Hydroxide-Modified Carbon Cloth Electrodes: A Simple Sensing Method.

Excessive ammonia nitrogen can potentially compromise the safety of drinking water. Therefore, developing a rapid and simple detection method for ammonia nitrogen in drinking water is of great importance. Nickel-copper hydroxides exhibit strong catalytic capabilities and are widely applied in ammonia nitrogen oxidation.

In Situ Preparation of Metallic Copper Nanosheets/Carbon Paper Sensitive Electrodes for Low-Potential Electrochemical Detection of Nitrite.

In the realm of electrochemical nitrite detection, the potent oxidizing nature of nitrite typically necessitates operation at high detection potentials. However, this study introduces a novel approach to address this challenge by developing a highly sensitive electrochemical sensor with a low reduction detection potential. Specifically, a copper metal nanosheet/carbon paper sensitive electrode (Cu/CP) was fabricated using a one-step electrodeposition method, leveraging the catalytic reduction properties of copper's high occupancy d-orbital.

A novel electrode for simultaneous detection of multiple heavy metal ions without pre-enrichment in food samples.

Integrating a pre-enrichment step into electrochemical detection methodologies has traditionally been employed to enhance the performance of heavy metal detection. However, this augmentation also introduces a degree of intricacy into the sensing process and increases energy consumption. In this work, Mo-doped WO is grown in situ on carbon cloth by one-step electrodeposition.

Sensitive Electrochemical Detection of Ammonia Nitrogen via a Platinum-Zinc Alloy Nanoflower-Modified Carbon Cloth Electrode.

As a common water pollutant, ammonia nitrogen poses a serious risk to human health and the ecological environment. Therefore, it is important to develop a simple and efficient sensing scheme to achieve accurate detection of ammonia nitrogen. Here, we report a simple fabrication electrode for the electrochemical synthesis of platinum-zinc alloy nanoflowers (PtZn NFs) on the surface of carbon cloth.

Electrocardiogram-Based Biometric Identification Using Mixed Feature Extraction and Sparse Representation.

(1) Background: The ability to recognize identities is an essential component of security. Electrocardiogram (ECG) signals have gained popularity for identity recognition because of their universal, unique, stable, and measurable characteristics. To ensure accurate identification of ECG signals, this paper proposes an approach which involves mixed feature sampling, sparse representation, and recognition.

In-situ growth of porous rod-like tungsten oxide for electrochemical determination of cupric ion.

Preconcentration can effectively enhance the detection performance of electrodes in the electrochemical detection of heavy metal ions, but it also presents challenges for real-time monitoring. Several attempts have been made to optimize preconcentration by improving the adsorption capacity or detection mechanism of the electrode. The valence transfer of tungsten oxide between W/W can participate in the reduction between the electrode material and heavy metal ions, playing a role in preconcentration to some extent.

A near-infrared light triggered fluormetric biosensor for sensitive detection of acetylcholinesterase activity based on NaErF: 0.5 % Ho@NaYF upconversion nano-probe.

Acetylcholinesterase (AChE), as an important neurotransmitter, is widely present in the peripheral and central nervous systems. The aberrant expression of AChE could cause diverse neurodegenerative diseases. Herein, we developed a facile and interference-free fluorimetric biosensing platform for highly sensitive AChE activity determination based on a NaErF: 0.

Fabrication of ZnO/Carbon Quantum Dots Composite Sensor for Detecting NO Gas.

ZnO and carbon quantum dots (CQDs) were synthesized by a hydrothermal method, and CQDs were doped into ZnO by a grinding method to fabricate a ZnO/CQDs composite. The X-ray diffraction and the scanning electron microscope revealed that the as-prepared ZnO has a structure of wurtzite hexagonal ZnO and a morphology of a flower-like microsphere which can provide more surface areas to adsorbed gases. The ZnO/CQDs composite has a higher gas sensitivity response to NO gas than ZnO microspheres.

Synthesis of three-dimensional hierarchical furball-like tungsten trioxide microspheres for high performance supercapacitor electrodes.

A hierarchical furball-like WO electrode material, based on stainless-steel mesh, was successfully synthesized a simple hydrothermal method. The electrode materials obtained are made from a self-assembled nanorod core and a connected/quasi-connected nano-thorn network shell, and could help utilize all the surface or near-surface regions for faradaic reaction. Furthermore, the furball-like WO special microstructure provides a more effective charge storage area, exhibiting a high specific capacitance of 8.

In situ synthesis of hierarchical platinum nanosheets-polyaniline array on carbon cloth for electrochemical detection of ammonia.

In this work, a self-supported electrode has been designed and fabricated based on carbon cloth-supported polyaniline array and Pt nanosheets (Pt-PANI-CC). PANI array was firstly loaded on the surface of CC via chronoamperometry technique, and then, Pt nanosheets were deposited on the per-grown PANI array through amperometric measurement. The hierarchical structure of Pt-PANI-CC electrode and unique sheet-like Pt nanoparticles offered large specific surface and response centers.

An efficient colorimetric high-throughput screening method for synthetic activity of tyrosine phenol-lyase.

Tyrosine phenol-lyase (TPL) naturally catalyzes the reversible β-elimination of l-tyrosine to phenol, pyruvate and ammonium. With its reverse reaction (synthetic activity), l-tyrosine and its derivatives could be synthesized with high atom economy, which are widely used in pharmaceutical industries. In this study, a high-throughput screening method for synthetic activity of TPL was developed.

Process development for efficient biosynthesis of L-DOPA with recombinant Escherichia coli harboring tyrosine phenol lyase from Fusobacterium nucleatum.

The tyrosine phenol lyase (TPL) catalyzed synthesis of L-DOPA was regarded as one of the most economic route for L-DOPA synthesis. In our previous study, a novel TPL from Fusobacterium nucleatum (Fn-TPL) was exploited for efficient biosynthesis of L-DOPA. However, the catalytic efficiency decreased when the reaction system expanded from 100 mL to 1 L.

Biochemical characterization of a novel tyrosine phenol-lyase from Fusobacterium nucleatum for highly efficient biosynthesis of l-DOPA.

Tyrosine phenol-lyase (TPL) catalyzes the reversible cleavage of l-tyrosine to phenol, pyruvate and ammonia. When pyrocatechol is substituted for phenol, l-dihydroxyphenylalanine (l-DOPA) is produced. The TPL-catalyzed route was regarded as the most economic process for l-DOPA production.

Construction of leaf-like CuO-CuO nanocomposites on copper foam for high-performance supercapacitors.

Leaf-like CuO-CuO nanosheets have been prepared on copper foam by a one-step simple anodization method, which can be used as an advanced binder-free supercapacitor electrode. The performance of the CuO-CuO/Cu foam electrode was optimized through controlling and restraining the current density and reaction time. The prepared electrode exhibits a very high specific capacitance (1.

A high-performance supercapacitor electrode based on tremella-like NiCO@NiO core/shell hierarchical nanostructures on nickel foam.

Tremella-like nickel oxalate@nickel oxide (NiCO@NiO) core/shell hierarchical nanostructures have been successfully synthesized on nickel foam, using Ni foam as a current collector, a Ni source and a three-dimensional (3D) substrate, through a facile hydrothermal method followed by an electrochemical activation process. The prepared samples can be directly used as binder-free electrodes for supercapacitors. The tremella-like morphology, together with the NiCO nanoblocks on 3D Ni foam, significantly increases the amount of active sites for redox reactions and the conductivity of the electrode material, shortens the diffusion pathway for ions, facilitates the effective penetration of the electrolyte, and lowers the intrinsic equivalent series resistance, demonstrating good potential for energy storage application.

Computational simulation and preparation of fluorescent magnetic molecularly imprinted silica nanospheres for ciprofloxacin or norfloxacin sensing.

A magnetic molecularly imprinted fluorescent sensor for the sensitive and convenient determination of ciprofloxacin or norfloxacin in human urine was synthesized and characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, ultraviolet/visible spectroscopy, and fluorescence spectroscopy. Both cadmium telluride quantum dots and ferroferric oxide nanoparticles are introduced into the polymer for the rapid separation and detection of the target molecules. The synthesized molecularly imprinted polymers were applied to detect ciprofloxacin or its structural analog norfloxacin in human urine with the detection limit 130 ng/mL.

[Transfer calibration for alcohol determination using temperature-induced shortwave near infrared spectra].

The authors studied the temperature influence on short-wave near-infrared spectra of ethanol aquatic solution and utilized four methods to establish the transfer partial least squares (PLS) calibration model: direct transfer calibration, global calibration, orthogonal signal correction (OSC) and generalized least squares weighting (GLSW). The PLS models were built at four temperatures: 15, 25, 35 and 40 degrees C. The results showed that direct calibration provided high prediction bias: significantly high positive prediction bias for a temperature lower than calibration temperature and negative bias for higher temperatures.

Short-wave near-infrared spectrometer for alcohol determination and temperature correction.

A multichannel short-wave near-infrared (SW-NIR) spectrometer module based on charge-coupled device (CCD) detection was designed. The design relied on a tungsten lamp enhanced by light emitting diodes, a fixed grating monochromator and a linear CCD array. The main advantages were high optical resolution and an optimized signal-to-noise ratio (0.

Thermal dynamics of graphene edges investigated by polarized Raman spectroscopy.

In this report, we present Raman spectroscopy investigation of the thermal stability and dynamics of graphene edges. It is found that graphene edges (both armchair and zigzag) are not stable and undergo modifications even at temperature as low as 200 °C. On the basis of polarized Raman results, we provide possible structural models on how graphene edges change during annealing.