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The reservoir sediment is formed by the combination and precipitation of clay, sand, organic nutrients and inorganic minerals in the reservoir. The reservoir sediment usually exists in the form of irregular and heterogeneous clay glue, which is in a fluid plastic state with good plasticity and relatively loose between particles. The accumulation of sediment in the reservoir will weaken the water storage and flood control capacity of the reservoir, and then reduce the capacity of the reservoir, shorten the life of the reservoir, and affect the shipping traffic. In addition, the long-term accumulation of reservoir sediment may cause pollution to the surrounding environment and reduce the water environment safety index, thus posing a potential threat to human survival. Therefore, it is urgent to make resource utilization of reservoir sediment. In order to improve the added value utilization rate of reservoir sediment in the field of building materials, this paper uses the reservoir sediment as auxiliary cementing material to prepare pervious concrete. Through the orthogonal test, the mix ratio design optimization of pervious concrete with reservoir sediment is studied, and the effects of slag powder, reservoir sediment and reinforcement agents on the performance indexes of pervious concrete with reservoir sediment, such as dry density, total porosity, effective porosity, permeability coefficient, ultrasonic pulse velocity and 28 d compressive strength are analyzed. The relationship between ultrasonic pulse velocity and porosity, permeability coefficient and 28 d compressive strength is studied, and the evolution law of the quality of the specimen and ultrasonic pulse velocity with the number of freeze-thaw cycles is explored. The results show that the dry density, compressive strength and ultrasonic pulse velocity of pervious concrete decrease continuously with the addition of reservoir sediment, and the porosity and permeability coefficient increase continuously. When slag powder is added, the dry density, compressive strength and ultrasonic pulse velocity of the specimen first increase and then decrease, and the porosity and permeability coefficient first decrease and then increase. The reinforcement agent has no obvious effect on the performance index of the specimen. The curve fitting of ultrasonic pulse velocity with porosity, permeability coefficient and 28 d compressive strength is well correlated. With the increase in the number of freeze-thaw cycles, the quality loss rate of the specimen increases gradually, the ultrasonic wave speed decreases gradually, and the slag powder and reinforcing agent can improve the freeze--thaw durability of the specimen. The research findings will promote the development and application of reservoir sediment in the preparation of building materials, and is expected to serve as a reference for the further application of reservoir sediment permeable concrete. [ABSTRACT FROM AUTHOR]

Objective: To investigate the analgesic and sedative effects of inhaling a mixture of nitrous oxide and oxygen on burn patient during and after dressing change., Methods: A total of 240 burn patients hospitalized in the Institute of Burn Research of Changhai Hospital Affiliated to the Second Military Medical University, Department of Burns of the First People's Hospital in Zhengzhou, and Department of Burns and Plastic Surgery of General Hospital of Ningxia Medical University from October 2011 to September 2012 were enrolled in our study, and they were all in accordance with the inclusion criteria. The 240 patients were divided into control group (n = 60, treated with inhalation of oxygen during dressing change) and treatment group (n = 180, treated with inhalation of a mixture of 65% nitrous oxide and oxygen during dressing change) according to the computer-generated list of random number. The other treatments in control group and treatment group were the same. Before, during, and after dressing change, heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), oxygen saturation (SO2), and adverse effects were observed. The degree of pain and anxiety felt by the patients were respectively evaluated with the visual analogue scale (VAS) and Chinese version of the burn specific pain anxiety scale (C-BSPAS) at the same time points as above. Data were processed with analysis of covariance, chi-square test, analysis of variance, and rank sum test., Results: There were no significant differences between control group and treatment group in the levels of HR, SBP, DBP, and SO2 before dressing change (with F values respectively 0.76, 0.06, 1.11, 0.70, P values all above 0.05). Compared with those of control group, the levels of HR, SBP, DBP, and SO2 in treatment group were significantly ameliorated during dressing change (with F values respectively 81.78, 146.36, 226.44, 205.62, P values all below 0.01). After dressing change, the levels of DBP in the two groups were close (F = 0.31, P > 0.05), but the levels of HR, SBP, and SO2 showed statistical differences (with F values respectively 7.02, 8.69, 12.23, P < 0.05 or P < 0.01). Before dressing change, the VAS scores were approximate between control group and treatment group (Z = 0.21, P > 0.05). Compared with those in control group (9.4 ± 0.7, 1.7 ± 2.5), the VAS scores were significantly lowered in treatment group during and after dressing change (1.6 ± 1.3, 0.7 ± 1.1, with Z values respectively 11.84, 3.35, P values all below 0.01). There was no significant difference in C-BSPAS score between control group and treatment group before dressing change (Z = 0.62, P > 0.05). Compared with those in control group (75 ± 13, 73 ± 12), the C-BSPAS scores in treatment group were decreased during and after dressing change (9 ± 15, 9 ± 14, with Z values respectively 11.91, 12.28, P values all below 0.01). There were no obvious adverse effects in two groups before, during, and after dressing change., Conclusions: A mixture of nitrous oxide and oxygen seems to have obvious analgesic and sedative effects on burn patients during dressing change, and it can be widely used.

Objective: To investigate the feasibility of constructing a skin tissue engineering covering on chitinous membrane using rat epidermal stem cells (ESCs)., Methods: Rat ESCs were isolated and cultured by cold digestive method and collagen type IV adherent method. Cell colonies were observed with inverted microscope. Expressions of DNA and RNA of ESCs were detected with laser scanning confocal microscope. Growth curves of cells were determined with Alamar BlueTM colorimetric method. Expressions of surface markers of ESCs (CD29, CD71, CD49d, and CD34) were detected with flow cytometer. Positive expressions of CK15, CK19, and P63 of ESCs were determined by immunohistochemistry. Influence of original chitinous membrane leachate in different dilutions on ESCs was observed. Condition of growth of ESCs on the vehicle was observed., Results: Isolated cultured cells were verified as ESCs, of which the doubling generation time was 48 hs. CD29 and CD49d were positive; CD71 and CD34 were negative; CK19, CK15, and P63 were positive. Compared with that of control group, ESCs cultured in chitinous membrane leachate showed slight cell proliferation when diluted to 1:8-1:512 dilutions, but there was no statistically significant difference (P > 0.05). The checkerboard-form cell colonies of ESCs could be visualized with naked eyes on the chitinous membrane in 2-4 weeks of culture. A multitude of ESCs were seen to grow on fibres under microscope., Conclusions: Chitinous membrane may be used as ESCs culture vehicle, and biological compatibility is good.