Electrochemical determination of chemical oxygen demand using Ti/TiO2 electrode.

To overcome the shortcomings of the conventional potassium dichromate method (PDM) for monitoring chemical oxygen demand (COD) of waters, many efforts have been made on developing quick and environment-friendly techniques. Among all alternatives, electrochemical (EC) techniques are very competitive due to their relatively simple devices and quickness. A number of electrodes have been fabricated to investigate electrochemical determination of COD. However, little work has been reported on Ti/TiO2 based electrode for this purpose. In the present work, Ti/Ti/TiO2 electrode was simply prepared by anodic oxidation of pure titanium. Aqueous solutions of potassium hydrogen phthalate and phenol were electrolyzed by chronocoulometry in a three-electrode system with Ti/Ti/TiO2 as working electrode (anode). Organic compounds were electrochemically oxidized on Ti/Ti/TiO2 electrode by hydroxyl radicals and the released electrons were recorded and transferred to currents. The electric currents were proportional to the COD values of the water samples being investigated. Based on data of COD values and corresponding currents, a linear regression equation was obtained for a certain kind of waste water. With the regression equation, current of an unknown water sample was transferred to its COD value. Conditions for the presented EC method were set up as cell voltage 2.0V v.s. SCE and pH 7.0. The linear range of COD was of about 25~530 mg/L. COD values of real waste water samples were measured by Ti/Ti/TiO2 electrode and the relative errors were all in the range of ±8% compared with data determined by conventional PDM. The electrochemicalmethodology was successfully applied to evaluate COD in waste water

Heat shock transcription factor 1 preserves cardiac angiogenesis and adaptation during pressure overload

To examine how heat shock transcription factor 1 (HSF1) protects against maladaptive hypertrophy during pressure overload, we subjected HSF1 transgenic (TG), knockout (KO) and wild type (WT) mice to a constriction of transverse aorta (TAC), and found that cardiac hypertrophy, functions and angiogenesis were well preserved in TG mice but were decreased in KO mice compared to WT ones at 4 weeks, which was related to HIF-1 and p53 expression. Inhibition of angiogenesis suppressed cardiac adaptation in TG mice while overexpression of angiogenesis factors improved maladaptive hypertrophy in KO mice. In vitro formation of vasculatures by microvascular endothelial cells was higher in TG mice but lower in KO mice than in WT ones. A siRNA of p53 but not a HIF-1 gene significantly reversed maladaptive hypertrophy in KO mice whereas a siRNA of HIF-1 but not a p53 gene induced maladaptive hypertrophy in TG mice. Heart microRNA analysis showed that miR-378 and miR-379 were differently changed among the three mice after TAC, and miR-378 or siRNA of miR-379 could maintain cardiac adaptation in WT mice. These results indicate that HSF1 preserves cardiac adaptation during pressure overload through p53-HIF-1-associated angiogenesis, which is controlled by miR-378 and miR-379

The analysis and fabrication of a novel tin-nickel mixed salt electrolytic coloured processing and the performance of coloured films for Al-12.7Si-0.7Mg alloy in acidic and alkali corrosive environments.

We present for the first time the analysis and fabrication of a novel Tin-Nickel mixed salt electrolytic coloured processing and the performance of coloured films for Al-12.7Si-0.7Mg alloy. This alloy is a novel alloy containing high silicon aluminum alloy extrusion profile which presents excellent mechanical properties as well as broad market prospects. Nevertheless, this kind of material is urgent in need of surface treatment technology. The orthogonal design and single factor tests were applied to optimize for electrolytic coloured technological conditions. By controlling operation conditions, the uniform electrolytic coloured films with different color were obtained. Analysis of microstructure showed that tin particles had been deposited in the coloured film. The coloured films, about 10 mu m thick, were uniform, dense and firmly attached to the substrate. After the coloured samples were maintained at 400AC for 1 h, or quenched from 300AC to room temperature, the coloured films did not change, demonstrating excellent thermostability and thermal shock resistance. Acid and alkali corrosion tests and potentiodynamic polarization showed that corrosion resistance of coloured sample was much better than those of untreated samples. After 240 h neutral salt spray test, protection ratings and appearance ratings of coloured films were Grade 9

Expression and distribution of PPP2R5C gene in leukemia

<p>Abstract</p> <p>Background</p> <p>Recently, we clarified at the molecular level novel chromosomal translocation t(14;14)(q11;q32) in a case of Sézary syndrome, which caused a rearrangement from TRAJ7 to the <it>PPP2R5C </it>gene. <it>PPP2R5C </it>is one of the regulatory B subunits of protein phosphatase 2A (PP2A). It plays a crucial role in cell proliferation, differentiation, and transformation. To characterize the expression and distribution of five different transcript variants of the <it>PPP2R5C </it>gene in leukemia, we analyzed the expression level of <it>PPP2R5C </it>in peripheral blood mononuclear cells from 77 patients with <it>de novo </it>leukemia, 26 patients with leukemia in complete remission (CR), and 20 healthy individuals by real-time PCR and identified the different variants of <it>PPP2R5C </it>by RT-PCR.</p> <p>Findings</p> <p>Significantly higher expression of <it>PPP2R5C </it>was found in AML, CML, T-ALL, and B-CLL groups in comparison with healthy controls. High expression of <it>PPP2R5C </it>was detected in the B-ALL group; however, no significant difference was found compared with the healthy group. The expression level of <it>PPP2R5C </it>in the CML-CR group decreased significantly compared with that in the <it>de novo </it>CML group and was not significantly different from the level in the healthy group. By using different primer pairs that covered different exons, five transcript variants of <it>PPP2R5C </it>could be identified. All variants could be detected in healthy samples as well as in all the leukemia samples, and similar frequencies and distributions of <it>PPP2R5C </it>were indicated.</p> <p>Conclusions</p> <p>Overexpression of <it>PPP2R5C </it>in T-cell malignancy as well as in myeloid leukemia cells might relate to its proliferation and differentiation. Investigation of the effect of target inhibition of this gene might be beneficial to further characterization of molecular mechanisms and targeted therapy in leukemia.</p

AngiotensinII Preconditioning Promotes Angiogenesis In Vitro via ERKs Phosphorylation

AngiotensinII (AngII) is involved in not only the formation of cardiac hypertrophy but also the development of cardiac remodeling both of which are associated with myocardial angiogenesis. This study was therefore performed to clarify the effects of AngII on the formation of vasculatures by cultured cardiac microvascular endothelial cells (CMVECs) after a long-period stimulation with or without the AngII preconditioning. Incubation with AngII for 18 hrs significantly impaired the formation of capillary-like tubes comparing to that without AngII. CMVECs with AngII pretreatment for 5 and 10 min formed more capillary-like tubes than those without AngII pretreatment, suggesting that preconditioning with AngII at a lower dose for a short period could prevent the further damage of CMVECs by a higher concentration of AngII. Moreover, AngII (10−7 M) stimulation for 5 and 10 min significantly induced the increase in extracellular signal-regulated protein kinases (ERKs) phosphorylation, and an ERKs inhibitor, PD98059, abrogated the increase in the formation of capillary-like tubes induced by the AngII-pretreatment. In conclusion, preconditioning with a lower concentration of AngII for a short period prevents the subsequent impairment of CMVECs by a higher dose of AngII, at least in part, through the increase in ERKs phosphorylation

Application of chaotic pulse width modulation control for suppressing electromagnetic interference in a half-bridge converter

It was proposed in the former research that chaos control can be used to suppress electromagnetic interference (EMI) in DC–DC converters. Analysis on a half-bridge converter is detailed in this study. Here, the practical example of the power supply of personal computers is given to show that, with an external chaotic signal to a pulse width modulation control circuit, the proposed approach can reduce EMI by reducing the amplitudes of power signals such as transformer current and output inductor currents at multiples of fundamental frequency

Cross-Linked Networks of 1,6-Hexanedithiol with Gold Nanoparticles to Improve Permeation Flux of Polyethersulfone Membrane

It is a great challenge to design and prepare polymeric membranes with excellent permeability and good rejection. In this study, a modifier of gold nanoparticles for crosslinking and self-assembly by 1,6-hexanedithiol is fabricated and used to modify the polyethersulfone membrane as an additive, which forms a uniform porous membrane by liquid&ndash;liquid phase conversion technology. The morphology of the membrane is investigated by scanning electron microscopy (SEM), the change of the hydrophilicity of the membrane surface after modification is measured by the contact angle goniometer, and the performance of the fabricated membrane is measured by evaluating the pure water flux and the rejection ratio of bovine serum albumin. The results indicate that the permeability of the modified membrane has a significant improvement. When the mass fraction of the modifying agent is 5 wt%, the water flux of the modified membrane reaches up to 131.6 L m&minus;2 h&minus;1, and has a good rejection ratio to bovine serum albumin. In short, this work plays an important role in improving the flux of the membrane and maintaining good separation performance

Optimizing solidification dendrites and process parameters for laser powder bed fusion additive manufacturing of GH3536 superalloy by finite volume and phase-field method

Investigating the surface morphology and microstructure of laser powder bed fusion (L-PBF) in solidification and optimizing process parameters is crucial for improving the accuracy and performance of cladding parts of GH3536 superalloy. In this study, a computational model incorporating Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) was utilized to simulate the mesoscale evolution of the molten pool in L-PBF for GH3536 superalloy. Furthermore, the growth of columnar dendrites along the fusion boundary under transient conditions was simulated utilizing a quantitative phase-field model. The impact of scanning speed and laser power on temperature distribution, molten pool size, surface morphology of cladding layer, and columnar dendrite spacing during solidification of single-track L-PBF were examined. The findings suggest that the molten pool undergoes a fast process characterized by significant temperature gradients. Increasing the laser power or reducing the scanning speed results in higher maximum molten pool temperature, as well as increased molten pool depth and width. Overlarge or undersized scanning speed and laser power can result in poor surface quality of the cladding layer. When the laser power was 120 W and the scan speed was 0.4 m/s, the cladding layer exhibited improved surface morphology, with finer columnar dendrites observed at the molten pool's base. This study delved into understanding the evolution characteristics of the molten pool and the growth process of columnar dendrites at the molten pool's base, providing valuable insights for determining appropriate experimental process parameters for L-PBF of GH3536 superalloy