Preparation and Free Radical Detection of Doped ZnO Nanomaterials

Nanomaterials play an important role in the field of optics and medicine, and rare earth cerium can act as a catalyst and a dopant to increase improve its optical properties. Used nanometer zinc oxide as a carrier, the Ag-ZnO and Ag-Ce-ZnO samples were prepared with the sol-gel method and characterized by X-ray diffractometer. The nanometer zinc oxide materials can generate the free hydroxyl radicals, so the methylene blue solution (MB) was used as the capture agent, and the free radicals produced by the doped nanometer zinc oxide were detected by UV-spectrophotometry. The results showed that the preparation particle size of the Ag-ZnO sample was about 75nm, particle size of the Ag-Ce-ZnO sample was about 70nm. The concentration of two samples treated with the dispersant PAAS generated hydroxyl radicals is much larger than the two samples treated with the dispersant SDBS. The doping of Ce ions not only improved the optical activity of the samples, but also increased the content of hydroxyl radicals. Rare-earth doped effe ctively improved the optical properties of the ZnO nanoparticles, and the effect of sample Ag-Ce-ZnO was better than Ag-ZnO samples. Discussion and study on the nature of both the nanometer zinc oxide and doped nanometer zinc oxide, as well as the method of preparation and the theory of produce hydroxyl radicals. In the experiment, doped nano-ZnO was used as carrier and methylene blue (MB) as capture reagent. This study provided a new method for the detection of free radicals drugs

The Effect of Tong-Xie-Yao-Fang on Intestinal Mucosal Mast Cells in Postinfectious Irritable Bowel Syndrome Rats

Objective. To investigate the effects of Tong-Xie-Yao-Fang (TXYF) on intestinal mucosal mast cells in rats with postinfectious irritable bowel syndrome (PI-IBS). Design. PI-IBS rat models were established using a multistimulation paradigm. Then, rats were treated with TXYF intragastrically at doses of 2.5, 5.0, and 10.0 g·kg−1·d−1 for 14 days, respectively. Intestinal sensitivity was assessed based on abdominal withdrawal reflex (AWR) scores and fecal water content (FWC). Mast cell counts and the immunofluorescence of tryptase and c-Fos in intestinal mucosa were measured; and serum IL-1β, TNF-α, and histamine levels were determined. Results. AWR reactivity and FWC which were significantly increased could be observed in PI-IBS rats. Remarkably increased mast cell activation ratio in intestinal mucosa, together with increased serum TNF-α and histamine levels, could also be seen in PI-IBS rats; furthermore, PI-IBS-induced changes in mast cell activation and level of serum TNF-α and histamine could be reversed by TXYF treatment. Meanwhile, tryptase and c-Fos expression were also downregulated. Conclusion. TXYF improves PI-IBS symptoms by alleviating behavioral hyperalgesia and antidiarrhea, the underlying mechanism of which involves the inhibitory effects of TXYF on activating mucosal mast cells, downregulating tryptase and c-Fos expression, and reducing serum TNF-α and histamine levels

Family-clinician shared decision making in intensive care units : cluster randomized trial in China

We thank the China Medical Board, which financially supported our study.Objective To investigate if a Family-Clinician Shared Decision-Making (FCSDM) intervention benefits patients, families and intensive care units (ICUs) clinicians.  Methods Six ICUs in China were allocated to intervention or usual care. 548 patients with critical illness, 548 family members and 387 ICU clinicians were included into the study. Structured FCSDM family meetings were held in the intervention group. Scales of SSDM, HADS, QoL2 and CSACD were used to assess families’ satisfaction and distress, patients’ quality of life, and clinicians’ collaboration respectively.  Results Comparing the intervention group with the control group at post-intervention, there were significant differences in the families’ satisfaction (P =0.0001), depression level (P =0.005), and patients’ quality of life (P =0.0007). The clinicians’ mean CSCAD score was more positive in the intervention group than controls (P < 0.05). There was no significant between-group differences on ICU daily medical cost, but the intervention group demonstrated shorter number of days’ stay in ICU (P=0.0004).  Conclusion The FCSDM intervention improved families’ satisfaction and depression, shortened patients’ duration of ICU stay, and enhanced ICU clinicians’ collaboration.  Practice implications Further improvement and promotion of the FCSDM model are needed to provide more evidence to this field in China.Publisher PDFPeer reviewe

Research on sub-station-area breaker failure protection based on the principle of current differential

On the basis of the principle of breaker failure protection delay and the analysis of the main factors which affect the protection, a sub-station-area breaker failure and dead-zone protection technical scheme based on the current differential principle is proposed. In this scheme, an incomplete current differential protection is structured by the breakers current transformer (CT) of the non-fault area, which is adjacent to the fault area. When the criteria of the incomplete current differential protection are satisfied, the adjacent breakers will trip to realise the isolation of the fault. This scheme is not only affected by the CT tailing and CT saturation, but also greatly reduces the time delay of breaker failure protection and achieves the free protection setting. The implementation of the project adopts an expandable architecture designed with the master slave mode, which could be achieved by high reliability with a flexible configuration of engineering and not relying on external time signals. Moreover, this scheme has the advantages of versatility and easier to implement. Also, it is preferable due to practicability and extended significance to popularise

Manipulation of Oxygen Vacancy for High Photovoltaic Output in Bismuth Ferrite Films

Very recently, the ferroelectric photovoltaic property of bismuth ferrite (BiFeO3, BFO) has attracted much attention. However, the physical mechanisms for its anomalous photovoltaic effect and switchable photovoltaic effect are still largely unclear. Herein, a novel design was proposed to realize a high photovoltaic output in BiFeO3 films by manipulating its oxygen vacancy concentration through the alteration of the Bi content. Subsequent results and analysis manifested that the highest photovoltaic output was achieved in Bi1.05FeO3 films, differing 1000 times from that of Bi0.95FeO3 films. Simultaneously, the origin of photovoltaic effect in all BiFeO3 films was suggested as the bulk photovoltaic mechanism instead of the Schottky effect. Moreover, oxygen vacancy migration should be the dominant factor determining the switchable photovoltaic effect rather than the ferroelectric polarization. A switchable Schottky-to-Ohmic interfacial contact model was proposed to illustrate the observed switchable photovoltaic or diodelike effect. Therefore, the present work may open a new way to realize the high power output and controllable photovoltaic switching behavior for the photovoltaic applications of BiFeO3 compounds

A Novel Method of Magnetic Sources Edge Detection Based on Gradient Tensor

The edge detection method based on the magnetic gradient tensor data plays an important role in magnetic exploration because it is free from geomagnetic interference and contains more abundant information. This paper proposes a new anomaly edge detection method using the magnetic gradient tensor components. The model is established to compare with other methods, such as directional total horizontal derivative (THDz), analytical signal (AS), tilt angle, theta map, and so on, under conditions of vertical magnetization, oblique magnetization, and noise interference. Through the study of the anomaly distribution of the rectangular model, it is observed that the edge detection method proposed in this paper is nearly impervious to noise interference, exhibits strong anti-interference capabilities, delivers a high-quality boundary identification effect, and provides greater accuracy in anomaly edges with minimal error. When multiple anomalous bodies are present, the edge detection results are less susceptible to interference from each other, resulting in higher resolution. The efficiency of the algorithm is demonstrated by real magnetic data from some study areas in Jiangxi Province, China. The experimental results show that the proposed method is more precise and accurate than the total horizontal derivative, analytical signal, tilt angle, and theta map methods

Microstructure and loading direction dependent hardening and damage behavior of laser powder bed fusion AlSi10Mg

The correlation between mechanical behavior and heterogeneous microstructure is still unclear for laser powder bed fusion AlSi10Mg. The present work investigates strain hardening and damage mechanisms with different build platform temperatures (35 ◦C and 200 ◦C) and loading directions (horizontal and vertical, building direction being vertical) to probe the effects of microstructure size and melt pool border orientation. The 35 ◦C microstructure involves load direction independent properties, with ductility determined by damage initiation occurring extremely close to final failure. In contrast, the 200 ◦C microstructure exhibits anisotropic mechanical behavior, as revealed by higher strain hardening capacity, earlier damage initiation and more dispersed damage distribution for the vertical loading direction. Although the vertical samples generally involve strain localization and crack propagation along the melt pool border, their ductility is not compromised compared to the horizontal counterparts. We attempt to explain these hardening and damage behaviors with stress partition and trade-off between phase stress and strain gradient

Review on the correlation between microstructure and mechanical performance for laser powder bed fusion AlSi10Mg

As important structural materials widely used in aerospace and automotive industries, aluminum alloys are perfect candidates for development of laser metal additive manufacturing (AM). Amongst AM aluminum alloys, laser powder bed fusion (LPBF) AlSi10Mg has received substantial attention due to its good printability and relatively low cost. Great efforts have been devoted to seek optimum process parameters that can enhance mechanical performance. However, a large scattering of material properties arises from the literature data, especially for the as built state, thus casting a shadow over further development of LPBF Al alloys. This review article aims to summarize the recent progresses on the characterization of microstructure, assessment of strengthening and damage mechanisms, evaluation of fracture and fatigue resistance, and attempts to build a primary comprehensive link between mechanical performance and microstructure for the as built state. Following the analysis of the state of the art, the review will finally provide an outlook on additional efforts needed to quantify the microstructure-property relation, based on which maximizing the potential of mechanical performance through optimizing microstructure may be achieved

How heterogeneous microstructure determines mechanical behavior of laser powder bed fusion AlSi10Mg

Laser powder bed fusion AlSi10Mg exhibits hierarchical and heterogeneous microstructure, which leads to anisotropic mechanical properties. The present work systematically investigated strength, ductility and their correlations to heterogeneous microstructure along different loading directions. Two AlSi10Mg samples presenting distinct features of Al-Si cellular structures and melt pool borders were analyzed, using combined tensile tests and digital image correlation measurements at both macro and micro scales. In addition, crystal plasticity modeling and simulation were conducted to reveal the deformation behavior and propensity to damage in the melt pool interiors and at the melt pool borders. Strain localizations are found in both the building direction and the perpendicular direction, due to weaker melt pool border and soft grain orientation, respectively. With the experimental and numerical results, it is demonstrated that the strength anisotropy mainly originates from the elongated Al-Si cellular structure, while the melt pool border plays a secondary role. Moreover, the ductility and its anisotropy appear to be determined by combined effects of strain localization, propensity to damage and constraints to crack formation. The findings of the present work unveil clearly how hierarchical and heterogeneous microstructure renders the macroscopic mechanical properties of additively manufactured Al alloys in different loading directions