The extract of Lychee’s peel and seed with (-)-epicatechin, (-)-epigallocatechin, and cyaniding-3-glucoside inhibits the corrosion of mild steel in HCl solution by adsorption of the effective ...compounds on steel surface.
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Various experimental conditions were tested for the green extract process of corrosion inhibitor from lychee fruit waste, and the optimal extract parameters were selected using potentiodynamic polarization. The best inhibition effect of the ethanol extract of lychee’s peel and seed by ultrasound for 1.5 h (EELPS) for mild steel in 0.5 M HCl was obtained at 600 mg/L using electrochemical and weight loss measurements. Theoretical calculations illustrate the adsorption sites and adsorption behavior of effective compounds. Due to the existence of hydroxyl groups and phenol rings in the main components, EELPS is considered to be a good inhibitor.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The extract of Longan’s peel and seed inhibits the corrosion of mild steel by adsorbing the effective compounds on the steel surface, resulting in the increased impedance values in Nyquist curves.
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Longan seed and peel were extracted and used for impeding the corrosion of mild steel in hydrochloric acid solution. Experimental analyses indicate that the water extract of Longan’s seed and peel, a mixed type inhibitor, can be chemically adsorbed onto the steel surface, and its inhibition effect rises with increasing extract concentration. To understand the adsorption mechanism and the contributions of the four main compounds of the extract to corrosion protection effect, quantum chemical methods and infrared spectrum were also employed. Theoretically, four main antioxidant compounds were regarded as effective components in the water extract of Longan’s seed and peel.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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Green corrosion inhibitors are of great benefit to the protection of pipes or tanks in seawater systems. The properties of the corrosion inhibitor such as toxicity and anticorrosion ...performance are closely related to its molecular structure. Some thiazole derivatives are commonly known as food flavors. The influences of two thiazole flavor ingredients on Cu corrosion in NaCl solution were analyzed in this study, namely, 4-methyl-5-vinylthiazole (MVT) and 5-(2-hydroxyethyl)-4-methylthiazole (HMT). Potentiodynamic polarization and electrochemical impedance spectroscopy measurements were employed to evaluate their anti-corrosion abilities. Theoretical calculations were conducted to investigate their possible adsorption modes. The thiazole ring endows the two compounds with the high inhibition performace. However, with a conjugated system, the ethenyl has a more pronounced contribution to electron donation and adsorption ability on the Cu surface than hydroxyethyl group.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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The use of the cosmetic ingredient cocamidopropylamine oxide (CAO) to inhibit the corrosion of steel in 0.5mol/LHCl is investigated. Electrochemical and weight loss methods were used ...to evaluate the inhibiting effect of CAO and the influences of inhibitor concentration and temperature were determined. It was found that CAO acted as a mix-type inhibitor and was adsorbed chemically onto the steel in HCl solution, and the maximum inhibition efficiency was found at critical micelle concentration (CMC) of CAO in tested corrosive media. Moreover, it was speculated that relationships of the two adsorption sites of the inhibitor and steel surface were different.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Silver nanoclusters capped by hyperbranched polyethylenimine (PEI) have been developed as a highly sensitive fluorescent and colorimetric pH sensor. The probe responds rapidly to pH fluctuations and ...has such absorption characteristics that the color changes from the colorless or a nearly colorless state to a colored state with increasing acidity, so PEI-capped Ag nanoclusters could be used as a color indicator for colorimetric pH detection. Quantitatively, the fluorescence intensity of PEI-capped Ag nanoclusters exhibits a linear fashion over the pH range of 5.02–7.96 and increases by around 10-fold approximately with greater fluorescence at higher pH values. The repulsion development and conformational change of PEI with decreasing pH induce the aggregation of Ag nanoclusters, leading to an obvious color change and fluorescence quenching of Ag nanoclusters at low pH values. As expected, the pH probe is also sensitive to the different buffer solutions, except for those containing some anions that could react with Ag nanoclusters. Besides, the ionic strength of the buffers has a little influence on the pH-responsive behavior. Our pH sensor with nanoscaled physical dimensions would be a promising candidate in the applications in biological, medical, and pharmaceutical fields.
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IJS, KILJ, NUK, PNG, UL, UM
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•A pH-mediated reversible fluorescence nanoswitch was designed for sensing 4-NP.•The fluorescence sensing mechanism was demonstrated deriving from IFE.•A portable polyamide film-based ...sensor was developed for visually detecting 4-NP.•The developed approach shows good sensitivity and selectivity for 4-NP.•The proposed method was successfully applied to detect 4-NP in real water samples.
Being a common hazardous waste, 4-nitrophenol (4-NP) has caused a serious threat to humans and environment. Therefore, rapid and selective detection of 4-NP, especially using a simple and portable instrument, is highly desired for human health and environmental monitoring. Herein, we develop a novel pH-mediated reversible fluorescence nanoswitch for selectively detecting 4-NP by using water-soluble fluorescent polymer carbon dots (PCDs) as a probe. The fluorescence of PCDs can be quenched by 4-NP via inner filter effect (IFE) because its excitation spectrum well overlaps with the absorption spectrum of 4-NP under alkaline condition. However, an obvious blue shift of the absorption peak of 4-NP occurs under acidic condition, causing the fluorescence recovery of PCDs due to the disappearance of IFE. On the basis of this principle, a pH-mediated reversible fluorescence nanoswitch was constructed and a broad linear range was obtained from 0.5 to 60 μM with a detection limit of 0.26 μM for 4-NP. Furthermore, this approach was successfully applied to detect 4-NP in real water samples and a portable polyamide film-based sensor was developed for visual detection of 4-NP, which offers a promising platform for the detection of 4-NP in on-site and resource-poor settings.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Carbon dots are first synthesized by one-pot method with malonic acid and urea.•The carbon dots possess small size, favorable optical properties, and good stability.•The fluorescence ...of carbon dots can be selectively quenched by picric acid in 10s.•The strategy improves the sensitivity for detection of picric acid down to 51nM.
In this work, novel water-soluble and blue fluorescent carbon dots (C-dots) were synthesized using one-pot hydrothermal method with malonic acid and urea, and were then used as a label-free fluorescent probe for selective, sensitive, and rapid determination of picric acid (PA). The sizes of the as-prepared C-dots were mainly distributed in the range of 1.5–3.0nm with an average diameter of 2.5nm. Moreover, the C-dots displayed blue fluorescence with an emission peak at 395nm (320nm excitation), which also showed good stability and anti-photobleaching ability. Interestingly, the fluorescence of C-dots could be selectively quenched by PA within 10s. Based on this phenomenon, a label-free fluorescence assay was proposed for specific determination of PA. The fluorescence intensity of probe showed a linear response to PA in the concentration range of 0.1 to 26.5μM with a low detection limit of 51nM (S/N=3). Finally, the resultant fluorescent probe was successfully applied to the detection of PA in real water samples.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Background
The prognostic significance of insulin‐like growth factor binding protein 2 (IGFBP2) expression has been explored in plenty of studies in human cancers. Because of the controversial ...results, the meta‐analysis was carried out to evaluate the relevance of IGFBP2 expression with the prognosis in various tumors.
Methods
The data searched from four databases (Pubmed, Embase, Cochrane library, and Web of science) was used to calculate pooled hazard ratios (HRs) in this meta‐analysis. Subgroup analyses were stratified by ethnicity, cancer type, publication year, Newcastle–Ottawa Scale score, treatments, and populations.
Results
Twenty‐one studies containing 5560 patients finally met inclusion criteria. IGFBP2 expression was associated with lower overall survival (HR = 1.57, 95% CI = 1.31–1.88) and progression‐free survival (HR = 1.18, 95% CI = 1.04–1.34) in cancer patients, but not with disease‐free survival (HR = 1.50, 95% CI = 0.91–2.46) or recurrence‐free survival (HR = 1.50, 95% CI = 0.93–2.40). The subgroup analyses indicated IGFBP2 overexpression was significantly correlated with overall survival in Asian patients (HR = 1.42, 95% CI = 1.18–1.72), Caucasian patients (HR = 2.20, 95% CI = 1.31–3.70), glioma (HR = 1.36, 95% CI = 1.03–1.79), and colorectal cancer (HR = 2.52, 95% CI = 1.43–4.44) and surgery subgroups (HR = 1.97, 95% CI = 1.50–2.58).
Conclusion
The meta‐analysis showed that IGFBP2 expression was associated with worse prognosis in several tumors, and may serve as a potential prognostic biomarker in cancer patients.
The prognostic significance of Insulin‐like growth factor binding protein 2 (IGFBP2) expression has been explored in plenty of studies in human cancers. However, the results remain controversial. Here, we conducted a systematic review and meta‐analysis to assess the relevance of IGFBP2 expression with the prognosis in various tumors.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Ag nanoclusters functioned by hyperbranched polyethyleneimine have been developed as a new fluorescent and colorimetric platform for sensitive and selective recognition of halide ions (e.g., Cl–, ...Br–, and I–). The recognition mechanism is based on the unique reactions between halide ions and the silver atoms. In particular, halide-induced oxidative etching and aggregation can produce a strong fluorescence quenching of Ag nanoclusters. This sensing system exhibits a remarkably high selectivity toward halide ions over most of anions and cations and shows good linear ranges and lower detection limits: the linear ranges are 0.5–80 μM for Cl–, 0.1–14 μM for Br–, and 0.05–6 μM for I–, respectively; the limits of detection for Cl–, Br–, and I–, at a signal-to-noise ratio of 3, are estimated to be 200, 65, and 40 nM, respectively. Specifically, Br– and I– could be recognized selectively in the coexistence with Cl– under the condition of higher ionic strength, which is a significant advantage in the detection of Br– and I– in real samples. In addition, the recognition of halide could be performed by the colorimetric method, which is also attractive and promising because of its simplicity, rapidity, reliability, and low cost. Furthermore, this sensing system has been applied successfully to the detection of Cl– in real water samples.
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IJS, KILJ, NUK, PNG, UL, UM
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•A dual-signal responsive sensor was designed to detect GSH based on MnO2 nanoflakes.•This sensor combined the advantages of RRS and colorimetry for the detection of GSH.•The sensor ...was successfully applied to detect GSH in the drug samples.•This work broadens the application of RRS technique in the analytical field.
Glutathione (GSH) plays a critical role in the living system and its abnormalities are closely associated with numerous clinical diseases. Thus, monitoring and detecting the content of GSH in the living system is still of great importance. Herein, a novel dual-signal responsive optical sensor is developed by using resonance Rayleigh scattering (RRS) and colorimetry for sensitive detection of GSH. In this sensor, MnO2 nanoflakes are used as both GSH recognizer and signal transducer of RRS and colorimetry. The solution of MnO2 nanoflakes shows strong RRS and absorption signals because MnO2 nanoflakes possess a large surface area and high molar extinction coefficient. However, MnO2 can be reduced to Mn2+ and MnO2 nanoflakes can be etched to small nanoparticles by GSH, causing both the RRS and absorption signals to decrease. Based on the change of RRS signal and absorbance of MnO2 nanoflakes, a novel dual-signal responsive optical sensor is successfully constructed to detect the content of GSH. The as-developed optical sensor toward GSH presents a favorable sensitivity with a detection limit of 0.033 and 0.67 μM for RRS and colorimetry, respectively. Furthermore, the as-developed approach is straightforward, quickly responsive, free-label, and cost-effective. More significantly, this method combines the advantages of RRS and colorimetry for the detection of GSH. Beyond this, the proposed RRS method has also been successfully utilized to detect the content of GSH in glutathione injection samples.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
