The simultaneous electrochemical determination of myricetin and rutin remains a challenge due to their indistinguishable potentials. To solve this problem, we constructed a ternary platinum nanoparticle, reduced graphene oxide, multi-walled carbon nanotubes (Pt@r-GO@MWCNTs) nanocomposite via a facile one-pot synthetic method. Under the optimized conditions, the ternary Pt@r-GO@MWCNTs nanocomposite exhibited good electrocatalytic activity toward myricetin and rutin via solid phase extraction and excellent performance for the simultaneous determination of myricetin and rutin. The oxidation peak current of myricetin was proportional to its concentrations in the range of 0.05-50 μM with a detection limit of 0.01 μM (S/N = 3). The linear range for rutin was 0.05-50 μM with a detection limit of 0.005 μM (S/N = 3). The ternary nanocomposite sensor also exhibited good reproducibility and stability, and was successfully used for the simultaneous determination of myricetin and rutin in real orange juice samples with recoveries ranging between 100.57% and 108.46%.
Nanoparticles of cadmium sulfide(CdSNCs) have been successfully prepared by a facilely sonochemical method from an aqueous solution of cadmium chloride and sodium sulfide.The size of the CdSNCs prepared was about 2-5 nm according to X-ray diffraction spectra and transmission electron microscopy images.The electrochemical behaviors of the CdSNCs modified glassy carbon electrode(GCE) have been studied and showed distinct advantages,such as higher catalysis activity and lower detection limit for phenol.A novel phenol sensor was constructed through modification of CdS nanoparticles on a GCE.The electrode showed good electrochemical activity in pH 6.0 phosphoric acid buffer solution.Experimental results showed that phenol could be oxidized by the modified electrode to form a detectable product.The linear range for phenol determination ranged from 2.0×10-7 mol/L to 2.0×10-4 mol/L with a detection limit of 2.0×10-8 mol/L.The possible mechanism of the electrochemical oxidation of phenol-solution was also investigated.
A signal-on electrochemical DNA biosensor was constructed for MnSOD gene detection by incorporating electrodeposited AuNPs and exonuclease III-assisted target recycling signal amplification strategy.
Three-dimensional (3D) titanates hierarchical macro/nano-architectures constructed by one-dimensional (1D) nanobelts are successfully synthesized by a hydrothermal-calcining process using metal Ti particles as a precursor. Their morphology and structure are characterized, and their photocatalytic reactivity to tetracycline hydrochloride (TC) is evaluated under visible-light irradiation. The results show that the 1D nanobelts are formed through hydrothermal reaction, and then those 1D nanobelts encircle the metal Ti particles precursor to form 3D macro/nano-architectures. The products with different phase composition, from hydrated titanium oxides to sodium titanates, are obtained by increasing the post-calcining temperatures from 200 degrees C to 800 degrees C. The photocatalytic degradation of TC is observed for all samples under visible-light irradiation, and the sample calcined at 600 degrees C achieves the best photocatalytic reactivity. The visible-light performance of as-synthesized catalysts is considered as a charge-transfer mechanism initiated by the photoexcitation of the surface-complex between TC molecules and titanates, and then followed by the photosensitization mechanism. Two intermediates are identified in the photodegradation process using liquid chromatography combined with mass spectrometry. In addition, the as-synthesized titanates are stable and can be used repeatedly, showing their promising prospect in the practical applications.
More than 90% of new potential therapeutic drugs have failed in clinical trials. In this study, the characteristics of failed new drugs for the treatment of seven types of cancer were first examined, followed by a review of the hazard ratios of survival in typical phase III clinical drug trials of these cancers from the last five years. The data suggested that population sizes in most clinical trials were limited to a certain level of detection. Evidently, each drug has its effect only in certain individuals with defined characteristics, and the success and failure of a new drug depend on these characteristics, such as ethnic group, sex, environmental conditions, pathological features, and genotype. Due to the complexity of the influence of multiple factors and the current limitation in understanding them, a large number of subgroups among patients may not have been recognized. Therefore, any decision only based on a few statistical comparisons, may not always provide correct judgement for a new drug. The drugs that are successful in clinical trials are “winners” regardless of how the differences in genotypes or other characteristics' influence on patients as compared to new drugs and placebos, or new and existing drugs. Drugs that are effective on certain characterizations or a specific group of patients are often categorized as a failure in clinical trials based on the current statistical criteria. Thus, previously failed drugs can be reevaluated and reutilized by analyzing whether these drugs have different effects on various genomic populations, or on patients who may emerge as subgroups based on other variables.
Anodization is a widely used method to obtain multicoloured oxidized titanium sheets. However, most researchers paid great attention to the colour-related properties instead of photoelectrical properties of titanium oxide film obtained by anodization. In this work, to study their photoelectrical properties, a series of multicoloured oxidized titanium sheets were prepared by anodization method, and UV–vis absorption and photocurrents were tested. The relationship between anodization voltages/anodization durations and photocurrents of titanium sheets was studied. Results show that titanium sheets have excellent photoelectrical performance. With the increase of anodization voltage, the number of UV–vis absorption peaks increased under visible light which means increasing absorption. When anodization duration increased, absorption band edge also increased in the visible light region, which means the band gap needed to produce charge transfer transition decreased. Under simulated sunlight and applied voltage of +0.4 V, photocurrent increased with the increase of either anodization voltage or anodization duration, and can be expressed by linear equations. In addition, anodization currents were recorded during anodization. Morphology, crystal structure and photoelectrical properties of anodized titanium sheets were characterized. The anodized titanium sheets can not only be used as decorative material in jewellery and architecture fields etc. but also are supposed to be used as photoelectrical catalyst in further work.
Herein, silver wire is synthesized electrochemically within a nanopipette using the nanopipette–liquid/liquid interface. The i–t curve characterizes the growth state of the silver wire. The higher rate of current increase indicates the faster electron transfer and the faster growth of the silver wire; conversely, when the current does not increase significantly with time, i.e., the rate of increase of the current is small, the growth rate of the silver wire is slow. The main driving force for the growth of silver into a linear structure is the theoretical current differential between the water and oil, caused by the concentration difference between the silver nitrate and ferrocene. The growth of the silver wire is also influenced by the shape of the nanopipette. If the diameter of the pipet increases quickly, silver wire tends to produce multibranched structures, while a smaller diameter makes it easier to obtain silver wire with fewer branches due to the confinement effect. This method is also applicable to the synthesis of gold within a nanopipette. The combination of nanopipette and metallic material using a liquid–liquid interface results in a broader application of nanopipettes for nanopore sensors, nanopore electrodes, bipolar electrodes, etc.
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