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In the isolated structure design, calculating the structure and isolation layer separately will cause great computational mistake for some layer, because of the unified horizontal seismic decrease coefficient. Using the mode superposition response spectrum method can get an accurate result of reinforcement assembly and structural deformation. The isolation structure is consisting of the isolation layer and the upper structure, whose damping ratios are different. In the mode-superposition response spectrum method, the way to calculate the isolation structure damping ratio is the key. Through the energy method, the mode damping ratio formula and the simplified form were derived for isolated structure. Using the response spectrum in GB 50011-2010, the earthquake response of isolated structure can be calculated. The application to a 16 stories base-isolation frame shows that the base shear of the frame calculated by mode-superposition response spectrum method agrees well with the result calculated by time history method. [ABSTRACT FROM AUTHOR]

The 'Code for seismic design of building' (GB 50011--2010) indicates that the earthquake response of energy dissipation structures can be calculated by linear analysis method using total damping ratio to determine the seismic influence coefficient, when the main structure has no or rare nonlinear deformation. How to calculate additional damping ratio is the key. Two existing additional damping ratio calculation methods, as well as the their difficulty, were summarized, i.e. code method and horizontal seismic decrease coefficient method. To avoid the difficulty, a new method fit for computer calculation, the free vibration decrement method, was proposed. Three methods were used to separately to calculate the additional damping ratio of two real structure and compare the accuracy of the free vibration decrement method with the other two methods. The result shows that the new method is simpler to operate by a computer and has the same calculation accuracy as the code method, while the horizontal seismic decrease coefficient method needs more research. [ABSTRACT FROM AUTHOR]

Background: Schisandra chinensis (Turcz.) Baill bee pollen extract (SCBPE) is often used as a functional food in China due to its good antioxidant property. However, its chemical compositions and effects on H9c2 cardiomyocytes against H2O2-induced cell injury still lacks of reports thus far. This study aimed to characterize the main components of SCBPE and investigate its protective effects against H2O2-induced H9c2 cardiomyocyte injury. Methods: The main components of SCBPE were analyzed via ultraperformance liquid chromatography–quadrupole time-of-flight tandem mass spectrometry (UPLC–QTOF MS/MS). The three main nucleosides in SCBPE were quantitatively analyzed via ultraperformance liquid chromatography–diode array detection. Furthermore, the potential mechanism by which SCBPE exerts protective effects against H2O2-induced H9c2 cardiomyocyte injury was explored for the first time via cell survival rate measurements; cell morphological observation; myocardial superoxide dismutase (SOD) activity and malondialdehyde (MDA) and glutathione (GSH) level determination; flow cytometry; and quantitative polymerase chain reaction. Results: Two carbohydrates, three nucleosides, and nine quinic acid nitrogen-containing derivatives in SCBPE were identified or tentatively characterized via UPLC–QTOF MS/MS. The nine quinic acid nitrogen-containing derivatives were first reported in bee pollen. The contents of uridine, guanosine, and adenosine were 2.4945 ± 0.0185, 0.1896 ± 0.0049, and 1.8418 ± 0.0157 μg/mg, respectively. Results of in vitro experiments showed that cell survival rate, myocardial SOD activity, and GSH level significantly increased and myocardial MDA level significantly decreased in SCBPE groups compared with those in H2O2 group. Cell morphology in SCBPE groups also markedly improved compared with that in H2O2 group. Results indicated that SCBPE protected H9c2 cardiomyocytes from H2O2-induced apoptosis by downregulating the mRNA expressions of Bax, cytochrome C, and caspase-3 and upregulating the Bcl-2 mRNA expression. Conclusions: This study is the first to report that SCBPE could protect against oxidative stress injury and apoptosis in H2O2-injured H9c2 cells. Results indicated that the nucleosides and quinic acid nitrogen-containing derivatives could be the main substances that exert protective effects against H2O2-induced H9c2 cardiomyocyte injury. [ABSTRACT FROM AUTHOR]

In the European honey bee, Apis mellifera, pollen foragers have a higher sucrose responsiveness than nectar foragers when tested using a proboscis extension response (PER) assay. In addition, Africanized honey bees have a higher sucrose responsiveness than European honey bees. Based on the biology of the Eastern honey bee, A. cerana, we hypothesized that A. cerana should also have a higher responsiveness to sucrose than A. mellifera. To test this hypothesis, we compared the sucrose thresholds of pollen foragers and nectar foragers in both A. cerana and A. mellifera in Fujian Province, China. Pollen foragers were more responsive to sucrose than nectar foragers in both species, consistent with previous studies. However, contrary to our hypothesis, A. mellifera was more responsive than A. cerana. We also demonstrated that this higher sucrose responsiveness in A. mellifera was not due to differences in the colony environment by co-fostering two species of bees in the same mixed-species colonies. Because A. mellifera foragers were more responsive to sucrose, we predicted that their nectar foragers should bring in less concentrated nectar compared to that of A. cerana. However, we found no differences between the two species. We conclude that A. cerana shows a different pattern in sucrose responsiveness from that of Africanized bees. There may be other mechanisms that enable A. cerana to perform well in areas with sparse nectar resources. [ABSTRACT FROM AUTHOR]

Abstract: The effect of sintering processes, such as open sintering, sintering inside a closed crucible, and sintering within a powder bed, on the microstructure and V–I characteristics of ZnO–Bi2O3-based varistor ceramics was investigated at sintering temperatures in the range 1000–1200°C. The results from the experiments showed that the microstructure and electrical properties of the samples varied according to the sintering method and temperature. Optimal values for the electrical characteristics of the varistor ceramics by different sintering processes were obtained when the sintering was conducted at 1100°C. At the same sintering temperature, the different processes affected the properties differently. At 1000°C, the samples sintered within a powdered bed showed better electrical properties than those subjected to the other two processes, while at 1100 or 1200°C, the samples sintered in an open crucible exhibited the best electrical properties. [Copyright &y& Elsevier]

Objectives: Scutellarin ( Scu ) is the main effective constituent of Erigeron breviscapus which has anti-oxidant, anti-apoptotic, anti-inflammatory and other therapeutic properties. The purpose of this study was to investigate the protective effect of Scu on myocardial infarction (MI) induced by isoprenaline (ISO)., Materials and Methods: The rats were subcutaneously injected with ISO (45 mg/kg) on the first day, then single tail-intravenously injected with different doses of Scu (10 mg/kg, 20 mg/kg, 40 mg/kg) for 7 consecutive days. The protective effect of Scu on ISO-induced MI was evaluated by measuring markers of heart injury in serum, levels of lipid peroxidation, and antioxidants in heart tissue, observing pathological changes of tissue, and detecting quantified expression of apoptotic-related family members and inflammation., Results: Compared with the model group, the concentration of troponin T (CTn-T) and troponin I (CTn-I), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) in the serum all decreased in the Scu high dose group. The activities of superoxide dismutase (SOD), catalase (CAT), and the content of reduced glutathione (GSH) in heart increased, and the content of malondialdehyde (MDA) and inducible nitric oxide synthase (iNOS) decreased. In addition, the histopathologic aspects showed that pathological heart change was found in the model group, and was reduced to varying degrees in the Scu group. Moreover, the expression of Bax, P53, Caspase3, Caspase9, cytochrome C, NGAL, NFκB, IL-1β and IL-6 in the heart decreased, while the expression of Bcl 2 increased., Conclusion: Scu could reduce the degree of MI induced by ISO by improving the antioxidant, anti-apoptotic, and anti-inflammatory capacities of the body.