An improved displacement-based adaptive pushover procedure based on factor modal combination rule

An accurate estimation of the applied load pattern is an essential component in each pushover procedure. Recently, a number of adaptive pushover methods have been proposed in which the effects of the higher modes as well as the progressive changes in the dynamic characteristics of structures are taken into account to compute the applied load pattern. The basic shortcoming of these advanced pushover methods is related to employing the quadratic modal combination rule, whereby the sign reversals of the modal load vectors are suppressed. In this study, an improved displacement-based adaptive pushover method is developed in which the applied load pattern is computed using the factor modal combination rule(FMC). In the proposed procedure, multiple load patterns, depending on the number of the modes considered, are determined in order to take into account the sign reversals of different modal load vectors. The accuracy of the proposed method is verifi ed for seven moment resisting frame buildings of 3, 9 and 20 stories with regularity or vertically geometric and mass irregularities subjected to 60 earthquake ground motion records. The results showed that the proposed methodology is capable of reproducing the peak dynamic responses with very good accuracy.

A new spatial coherence model and analytical coeffi cients for multi-support response spectrum combination

In this paper, a new spatial coherence model of seismic ground motions is proposed by a fitting procedure. The analytical expressions of modal combination （correlation） coefficients of structural response are developed for multi-support seismic excitations. The coefficients from both the numerical integration and analytical solutions are compared to verify the accuracy of the solutions. It is shown that the analytical expressions of numerical modal combination coefficients are of high accuracy. The results of random responses of an example bridge show that the analytical modal combination coefficients developed in this paper are accurate enough to meet the requirements needed in practice. In addition, the computational efficiency of the analytical solutions of the modal combination coefficients is demonstrated by the response computation of the example bridge. It is found that the time required for the structural response analysis by using the analytical modal combination coefficients is less than 1/20 of that using numerical integral methods.

Rapamycin enhances the susceptibility of both androgen-dependent and -independent prostate carcinoma cells to docetaxel

Background Docetaxel （DOC） therapy is well tolerated and shows high response rates in patients with hormone refractory prostate cancer （HRPC）. There are many reports on the effect of rapamycin （RPM） on the treatment of carcinogenesis. The goal of this study was to test whether RPM could enhance the susceptibility of both androgen-dependent and -independent prostate carcinoma cells to DOC. Methods Prostate cancer （PC） cell lines （LNCap, PC3 and AILNCap） were cultured and treated with RPM and DOC alone or in combination. The effects of therapeutic agents on cells were determined by the WST-1 assay. Apoptosis induction was confirmed by flow cytometric analysis. The apopcyto caspase colorimetric assay kit was applied to measure the activities of caspases 3 and 9. The antitumor effects of RPM and DOC against PC cells were also assessed in nude mice using four randomized groups： control, RPM, DOC and combination drug therapy by measuring tumor size. All the animals tolerated both RPM and DOC without significant weight loss. Results RPM and DOC caused dosage-dependent growth suppression of PC cells. RPM could increase the susceptibility of PC cells to DOC significantly, and combined treatment with RPM and DOC caused synergistic growth suppression in all examined PC cell lines by isobolographic analysis. Both RPM and DOC significantly induced apoptosis in a dosage-dependent manner. RPM （10 nmol/L）, DOC （1 nmol/L）, and combined treatment induced apoptosis rate were 8%, 17% and 38%, respectively （the control was 2%）. RPM could promote the apoptosis induced by DOC in PC cell lines. Both RPM and DOC significantly increased the caspase activity in a dosage-dependent manner. The relative activities of caspase 9 in control, RPM, DOC and RPM＋DOC groups were 0.22±0.02, 0.36±0.06, 0.47±0.05 and 0.84±0.08, respectively. The relative activities of caspase 3 were 0.21±0.02, 0.24±0.05, 0.42±0.06 and 0.81±0.09, respectively. Either RPM or DOC alone significantly inhibited the growth of PC cells in nude mice compared to the control. The combination of RPM and DOC produced a significant reduction in tumor volume when compared to RPM or DOC alone. After 5-week treatment, the tumor sizes of LNCap in control, RPM, DOC and RPM＋DOC groups were （570±56） mm3, （412±41） mm3, （425±46） mm3 and （221±26） mm3, respectively. Conclusions RPM could significantly increase the susceptibility of both androgen-dependent and -independent PC cells to DOC; the synergy of RPM and DOC was demonstrated. RPM enhanced the DOC-induced upregulation of caspase activity, resulting in an increasing number of cells in sub-G1 phases. The synergy of the combined treatment might be observed in both androgen-dependent and -independent PC cell lines.