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When multiple elements come together, hydraulic concrete develops cracks of varying widths, which huts the dependability of buildings. Therefore, with pertinent tools or procedures, swiftly ascertaining the safety status of hydraulic concrete cracks under diverse service conditions is required by conducting a quantitative and qualitative analysis of the elements influencing the onset of cracks. This paper took the safety status of hydraulic concrete cracks as the main body of research; every step of hydraulic conservation infrastructure from the ground up—design stage, construction process, operation environment, and impoundment operation—was thoroughly examined. After establishing a multi-dimensional and multi-level system for the safety status evaluation of hydraulic concrete cracks, the subjective exponential AHP and objective CRITIC method were employed to determine the weight of each factor. Then, the two weights were processed using an enhanced combination assignment method to produce a more scientifically developed combination weight. Furthermore, fuzziness and randomness were considered in the quantitative analysis thanks to integrating cloud theory and extension matter elements. In order to determine the safety evaluation findings for hydraulic concrete fractures, the maximum membership principle and the cloud picture were employed. The conclusion reached after using this method to evaluate Dianzhan Dam was that the crack had a safety grade of III, meaning that it greatly impacted the reliability of the dam, and called for prompt acceptance or repair measures to improve building efficiency and safety. [ABSTRACT FROM AUTHOR]

In this study, thermogravimetric measurements of nylon-6/polyethylene double-layer pouch wastes were conducted in N2 under a constant heating-rate mode, and the multiple heating-rate results were analyzed in terms of degradation features and specific temperatures. Experimental results show that the waste pyrolysis involves one reaction stage, and all specific parameters appear to increase with the heating rate. Kinetic analysis of non-isothermal data was thoroughly performed using various isoconversional model-free methods for the calculations of the activation energy, resulting in 143~215 kJ/mol over the whole pyrolysis process. By means of the model-fitting method, the reaction mechanism model g(α) and pre-exponential factor lnk0 are concurrently determined with the aid of the linear compensation effect. With such methodology proposed, the Avrami–Erofeev kinetic model A3/2 of g(α) = [−ln(1 − α)]2/3 is found to be the most appropriate mechanism function for describing the pyrolysis of the nylon-6/polyethylene waste along with lnk0 of 23.14 to 34.26 min−1. With the Arrhenius parameters thus obtained, the predictions were made and performed very satisfactorily to correlate experimental results. Additionally, the service life and thermodynamic parameters over the entire pyrolysis process were also estimated. [ABSTRACT FROM AUTHOR]

According to the demand for high-performance fibers for high-latitude ocean exploration and development, this paper selects representative products of high-performance liquid crystal fibers: thermotropic liquid crystal polymer fibers (TLCP) and poly p-phenylene terephthalamide (PPTA) fibers. Through a series of freeze–thaw (F–T) experiments for simulating a real, cold marine environment, we then measure the retention of mechanical properties of these two kinds of fibers. Before that, due to the difference in their chemical structures, we tested their Yang–Laplace contact angle (YLCA) and water absorption; the results suggested that PPTA fibers would absorb more moisture. Surprisingly, then, compared with thermotropic liquid crystal polymer (TLCP) fibers, the retention of the mechanical properties of poly p-phenylene terephthalamide (PPTA) fibers decreased by around 25% after the F–T experiments. The Fourier-transformed infrared (FT-IR) analysis, the attenuated total reflection (ATR) accessory analysis and the degree of crystal orientation measured by two-dimensional wide-angle X-ray diffraction (2D-WAXD) confirm that no changes in the chemical and the orientation structure of the crystal region of the fibers occurred after they underwent the F–T cycles. However, as observed by scanning electron microscopy (SEM), there are microcracks of various extents on the surface of the PPTA fibers, but they do not appear on the surface of TLCP fibers. It is obvious that these microcracks will lead to the loss of mechanical properties; we infer that the moisture absorbed by the PPTA fibers freezes below the freezing point, and the volume expansion of the ice causes the collapse of the microfibrillar structure. The two sorts of fibers subjected to the F–T experiments are immersed in a sodium chloride solution, and the amount of water infiltrated into the PPTA microfibrillar structure is evaluated according to the content of sodium ions in the fiber surface and subsurface layers through X-ray spectroscopy (EDS) elemental analysis. From the above analysis, we found that TLCP fibers can more effectively meet the operating standards of the severe and cold marine environment. [ABSTRACT FROM AUTHOR]

Thermal decomposition of tennis ball rubber (TBR) wastes in nitrogen and air has been studied through thermogravimetric analysis. The samples were thermally decomposed from room temperature to 950 K at heating rates of 3 to 20 K/min with a purging flow of 30 cm3/min. The degradation features and specific temperatures for two purging gases are thus compared according to the nonisothermal results. Kinetic analyses of two thermal decomposition processes have been isoconversionally performed using differential or integral methods. The activation energy as a function of mass conversion has been thus obtained over the entire decomposition range, varying from 116.7 to 723.3 kJ/mol for pyrolysis and 98.2 to 383.6 kJ/mol for oxidative thermal decomposition. The iterative Flynn–Wall–Ozawa method combined with the linear compensation effect relationship has been proposed for determining the pre-exponential factor and reaction mechanism function, resulting in chemical order reaction models of f(α) = (1 − α)5.7 and f(α) = (1 − α)5.8 for describing pyrolysis and the oxidative thermal degradation of TBR wastes, respectively. With these kinetic parameters, very satisfactory matching against experimental data has been obtained for both gases. Additionally, the thermodynamic parameters, such as the changes of entropy, enthalpy and Gibbs free energy, over the whole thermal degradation processes have also been evaluated. [ABSTRACT FROM AUTHOR]

Background: Prostate cancer (PCa) is the leading cause of death in men and has poor therapeutic outcomes. Methods: A novel endostatin 33 peptide was synthesized by adding a specific QRD sequence on the basis of the endostatin 30 peptide (PEP06) with antitumor activity. Then, bioinformatic analysis and subsequent experiments were performed to validate the antitumor function of this endostatin 33 peptide. Results: We found that the 33 polypeptides significantly inhibited growth, invasion and metastasis and promoted the apoptosis of PCa in vivo or vitro, which is more significant than PEP06 under the same conditions. According to 489 cases from the TCGA data portal, the α6β1 high expression group was closely associated with the poor prognosis (Gleason score, pathological N stage, etc.) of PCa and was mainly enriched in the PI3K-Akt pathway. Subsequently, we demonstrated that endostatin 33 peptide can down-regulate the PI3K-Akt pathway via the targeted inhibition of α6β1, thereby inhibiting the epithelial–mesenchymal transition and matrix metalloproteinase in C42 cell lines. Conclusion: The endostatin 33 peptide can exert antitumor effects by inhibiting the PI3K-Akt pathway, especially in tumors with a high expression of the integrin α6β1 subtype, such as prostate cancer. Therefore, our study will provide a new method and theoretical basis for the treatment of prostate cancer. [ABSTRACT FROM AUTHOR]

Euonymus hederaceus is distributed widely in the south of China; its stems and leaves have been used as folk medicines to treat many diseases such as renal deficiency and chronic diarrhea, traumatic injury, and abnormal menstruation. Chemical investigation of the leaves and stems of Euonymus hederaceus resulted in the isolation forthe first time and characterization of a new friedelane type triterpene with a molecular mass of 472 and molecular formula of C(30)H(48)O(4)by high resolution mass spectrometry. The (1)H-NMR (13)C-NMR and DEPT135(0)spectra matched the characteristic data of the proposed triterpene skeleton.The compound was finally identified as 28-hydroxyfriedelan-3-one-29-oic acid on the basis of spectroscopic evidence, including two dimensional nuclear magnetic resonance as well as its IR spectrum.