Determination of Catechol by Cetyltrimethylammonium Bromide Functionalized Graphene Modified Electrode

A simple and sensitive electrochemical sensor was prepared by using electrodeposition of the cetyltrimethylammonium Bromide (CTMAB ) functionalized Graphene (GR) on the glassy carbon electrode (GCE) to determine Catechol (CC) in water. The performance of the CTMAB functionalized GR sensor was studied and the analysis conditions of the CC were optimized. The experimental results showed that, compared with bare GCE, the redox peak current of CC on the modified electrode was obviously enhanced. Under the optimized conditions, the oxidation and reduction peak current all showed a good linear relationship with the concentration of CC from 5μmol/L to 1000 μmol/L. The detection limit of oxidation peak is 2.92 μmol/L, and that of reduction peak is 2.44 μmol/L. The recovery was founded to be in the range of 92.70 %~101.80 %. Moreover, the sensor could be used for the determination of CC in real samples with satisfactory results. And the mechanism of the sensitization of CC detected by CTMAB-GR modified GCE was discussed preliminarily

Determination of Catechol by Cetyltrimethylammonium Bromide Functionalized Graphene Modified Electrode

A simple and sensitive electrochemical sensor was prepared by using electrodeposition of the cetyltrimethylammonium Bromide (CTMAB ) functionalized Graphene (GR) on the glassy carbon electrode (GCE) to determine Catechol (CC) in water. The performance of the CTMAB functionalized GR sensor was studied and the analysis conditions of the CC were optimized. The experimental results showed that, compared with bare GCE, the redox peak current of CC on the modified electrode was obviously enhanced. Under the optimized conditions, the oxidation and reduction peak current all showed a good linear relationship with the concentration of CC from 5μmol/L to 1000 μmol/L. The detection limit of oxidation peak is 2.92 μmol/L, and that of reduction peak is 2.44 μmol/L. The recovery was founded to be in the range of 92.70 %~101.80 %. Moreover, the sensor could be used for the determination of CC in real samples with satisfactory results. And the mechanism of the sensitization of CC detected by CTMAB-GR modified GCE was discussed preliminarily

Determination of Catechol by Cetyltrimethylammonium Bromide Functionalized Graphene Modified Electrode

A simple and sensitive electrochemical sensor was prepared by using electrodeposition of the cetyltrimethylammonium Bromide (CTMAB ) functionalized Graphene (GR) on the glassy carbon electrode (GCE) to determine Catechol (CC) in water. The performance of the CTMAB functionalized GR sensor was studied and the analysis conditions of the CC were optimized. The experimental results showed that, compared with bare GCE, the redox peak current of CC on the modified electrode was obviously enhanced. Under the optimized conditions, the oxidation and reduction peak current all showed a good linear relationship with the concentration of CC from 5μmol/L to 1000 μmol/L. The detection limit of oxidation peak is 2.92 μmol/L, and that of reduction peak is 2.44 μmol/L. The recovery was founded to be in the range of 92.70 %~101.80 %. Moreover, the sensor could be used for the determination of CC in real samples with satisfactory results. And the mechanism of the sensitization of CC detected by CTMAB-GR modified GCE was discussed preliminarily

Determination of Catechol by Cetyltrimethylammonium Bromide Functionalized Graphene Modified Electrode

A simple and sensitive electrochemical sensor was prepared by using electrodeposition of the cetyltrimethylammonium Bromide (CTMAB ) functionalized Graphene (GR) on the glassy carbon electrode (GCE) to determine Catechol (CC) in water. The performance of the CTMAB functionalized GR sensor was studied and the analysis conditions of the CC were optimized. The experimental results showed that, compared with bare GCE, the redox peak current of CC on the modified electrode was obviously enhanced. Under the optimized conditions, the oxidation and reduction peak current all showed a good linear relationship with the concentration of CC from 5μmol/L to 1000 μmol/L. The detection limit of oxidation peak is 2.92 μmol/L, and that of reduction peak is 2.44 μmol/L. The recovery was founded to be in the range of 92.70 %~101.80 %. Moreover, the sensor could be used for the determination of CC in real samples with satisfactory results. And the mechanism of the sensitization of CC detected by CTMAB-GR modified GCE was discussed preliminarily

Human leukocyte antigen-G upregulates immunoglobulin-like transcripts and corrects dysfunction of immune cells in immune thrombocytopenia

Human leukocyte antigen-G is a non-classical major histocompatibility complex class I antigen with potent immune-inhibitory function. Human leukocyte antigen-G benefit patients in allotransplantation and autoimmune diseases by interacting with its receptors, immunoglobulin-like transcripts. Here we observed significantly less human leukocyte antigen-G in plasma from immune thrombocytopenia patients positive for anti-platelet autoantibodies compared with autoantibodies-negative patients or healthy controls. Besides, human leukocyte antigen-G is positively correlated with platelet counts in both patients and healthy controls. We also found less membrane-bound human leukocyte antigen-G and immunoglobulin-like transcripts on CD4+ and CD14+ cells in patients. Recombinant human leukocyte antigen-G upregulated immunoglobulin-like transcript 2 expression on CD4+ and immunoglobulin-like transcript 4 on CD14+ cells. Human leukocyte antigen-G upregulated IL-4 and IL-10, and downregulated tumor necrosis factor-α, IL-12 and IL-17 secreted by patient peripheral blood mononuclear cells, suggesting a stimulation of Th2 differentiation and downregulation of Th1 and Th17 immune response. Human leukocyte antigen-G-modulated dendritic cells from immune thrombocytopenia patients showed decreased expression of CD80 and CD86, and suppressed CD4+ T-cell proliferation compared to unmodulated cells. Moreover, human leukocyte antigen-G modulated cells from patients induced less platelet apoptosis. Human leukocyte antigen-G administration also significantly alleviated thrombocytopenia in a murine model of ITP. In conclusion, our data demonstrated that impaired expression of human leukocyte antigen-G and immunoglobulin-like transcripts is involved in the pathogenesis of immune thrombocytopenia; Recombinant human leukocyte antigen-G can correct this abnormality via upregulation of immunoglobulin-like transcripts, indicating that human leukocyte antigen-G can be a diagnostic marker and a therapeutic option for immune thrombocytopenia

An inverse problem in film/substrate indentation: extracting both the Young's modulus and thickness of films

In an indentation test, the effective Young's modulus of a film/substrate bilayer heterostructure varies with the indentation depth, a phenomenon known as the substrate effect. In previous studies investigating this, only the Young's modulus of the film was unknown. Once the effective Young's modulus of a film/substrate structure is determined at a given contact depth, the Young's modulus of the film can be uniquely determined, i.e., there is a one-to-one relation between the Young's modulus of the film and the film/substrate effective Young's modulus. However, at times it is extremely challenging or even impossible to measure the film thickness. Furthermore, the precise definition of the layer/film thickness for a two-dimensional material can be problematic. In the current study, therefore, the thickness of the film and its Young's modulus are treated as two unknowns that must be determined. Unlike the case with one unknown, there are infinite combinations of film thickness and Young's modulus which can yield the same effective Young's modulus for the film/substrate. An inverse problem is formulated and solved to extract the Young's modulus and thickness of the film from the indentation depth-load curve. The accuracy and robustness of the inverse problem-solving method are also demonstrated

The Value of Environmental Base Flow in Water-Scarce Basins: A Case Study of Wei River Basin, Northwest China

In the perennial river, environmental base flow, associated with environmental flow, is the base flow that should be maintained within the river channel throughout the year, especially in the dry season, to sustain basic ecosystem functions and prevent the shrinkage or discontinuity of a river. The functions of environmental base flow include eco-environmental functions, natural functions, and social functions. In this study, we provided a method based on these functions; this method estimated the function values per unit area, introduced the scarcity coefficient, multiplied by the corresponding water area, and summed over to quantify the value of environmental base flow from 1973 to 2015 in the Wei River Basin, the largest tributary of the Yellow River in Northwest China. We observed that there was a positive correlation between the total value of environmental base flow and its water yield, whereas this outcome was completely different in the benefit per unit discharge of environmental base flow, which was closely associated with the shortage of environmental base flow. This method can thus present the considerable value of environmental base flow in monetary terms in a simple and effective way and lay the foundation for further reasonable protection levels of environmental base flow

Calibration of Adjustment Coefficient of the Viscous Boundary in Particle Discrete Element Method Based on Water Cycle Algorithm

The viscous boundary has a direct influence on the accuracy of structural dynamic response analysis, and the absorbing effect of the viscous boundary is controlled by the adjustment coefficient. Therefore, a calibration model of the viscous boundary’s adjustment coefficient based on the water cycle algorithm is established for the particle discrete element to improve the accuracy of dynamic response analysis. First, the traditional viscous boundary theory is utilized to realize the viscous boundary’s application method in the particle discrete element via programming. This avoids the reflection and superposition of seismic waves at the boundary and makes the structural dynamic response with the particle discrete element more real and accurate. Second, for the complex and time-consuming adjustment coefficients determination, a calibration model based on the water cycle algorithm and Latin hypercube sampling is established for the adjustment coefficients in the particle discrete element method. Finally, this calibration model is employed for the seismic response analysis of a rockfill slope, the maximum velocity of rock in this rockfill slope being about 1.30 times that of a seismic wave. Comparing the rockfill slope response with fixed and viscous boundaries, the calibration’s accuracy and the viscous boundary’s feasibility are demonstrated, further expanding the research and application of the particle discrete element method in dynamic response analysis

Operation Performance and Seepage Flow of Impervious Body in Blast-Fill Dams Using Discrete Element Method and Measured Data

As a high-efficiency and low-investment method of dam construction, blast-fill dams have been widely used in water conservancy, mining engineering, soil and water conservation, disaster prevention and other projects. Through collecting data on the main projects of the blast-fill dams, the characteristics and development trends of blast-fill dams are analyzed in detail. Meanwhile, the design requirements of impervious bodies in the initial and reinforcement stages are systematically reviewed. Subsequently, with measured data of a typical blast-fill dam, the structural characteristics of blast-fill dams after blasting and the validity of the phreatic line height after reinforcement are analyzed using the discrete element method. We conclude that an appropriate construction schedule and flexible impervious material are critical features of the impervious body for a dam with large deformation. When the dam deformation is stable, a secondary treatment should be considered for the impervious body to improve the dam safety. The design ideas for the impervious body of blast-fill dams are also applicable to other dam types with large deformation for risk reduction, such as high rockfill dams, soft-rock dams and tailings dams, and have a certain significance for reference in the treatment of landslides and confined lakes