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Conventional semiempirical predictive models for seismically induced slope displacement (D) are generally developed based on as-recorded orthogonal ground motion components. Considering orthogonal records reveals that the predicted D is associated with intensity measure (IM) of a specific ground motion time history. However, current practice generally utilizes average IM (e.g., median over all horizontal ground motion orientations) as input of displacement models, and this tends to underestimate D when earthquake shaking along the downslope sliding direction is stronger than the average shaking level at a site. In this study, more than 190 million coupled sliding-block analyses were conducted using 3,092 ground motion records rotated over all orientations. Generic models were subsequently developed by integrating two machine learning algorithms for predictions of the maximum displacement (D100) or median displacement (D50) over all orientations. These models exhibit excellent generalization capability, yielding considerably lower bias and uncertainty than conventional polynomial forms. The results indicate that the predicted D100 could be significantly larger than D50 and the conventional displacement index for orthogonal records, and the D100 direction is dependent on both ground motion characteristics and slope properties. The proposed models outperform the existing models regarding ground motion directionality representation and prediction uncertainty mitigation. The associated mathematical equations are presented, with executable files also included for engineering applications. [ABSTRACT FROM AUTHOR]

Correlation coefficients for 5%‐damped spectral accelerations (SAs) of horizontal ground‐motion components have been extensively studied and applied in probabilistic seismic analysis using vector‐valued intensity measures (IMs). Such correlations are, however, not sufficient for structures with different damping ratios under multidirectional earthquake shakings. This paper presents a comprehensive study on the correlations between horizontal‐horizontal (H‐H), horizontal‐vertical (H‐V), and vertical‐vertical (V‐V) pairs of SAs for different damping ratios based on the NGA‐West2 ground motion database. The correlations of SAs with peak ground acceleration (PGA) and peak ground velocity (PGV) are also investigated. The uncertainty in correlations is measured by integrating the bootstrap method into the logic‐tree framework. Comparative results indicate that the correlation coefficients generally increase for IMs of larger damping ratios. The relative difference between the damping‐dependent and conventional 5%‐damped correlation coefficients can be notable, reaching 100% and 35% in the SA‐SA and SA‐PGV (or PGA) pairs, respectively. Based on the empirical correlation results, an artificial neural network is utilized to develop parametric models of the correlations and the executive files for implementing these models are provided. The ANN‐aided damping‐dependent correlation models developed can be considered as a generalization of the conventional 5%‐damped correlation models, and may serve as useful tool in applications such as ground‐motion selection and vector‐valued probabilistic seismic risk assessment for structure systems. [ABSTRACT FROM AUTHOR]

Objective: To detect the expression of hypoxia inducible factor 1 alpha (HIF-1α), glucose transporter protein-1 (GLUT-1) and vascular endothelial growth factor (VEGF) in human laryngeal carcinoma tissue, and to study the relationship between hypoxia and HIF-1α, GLUT-1, VEGF in human laryngeal carcinoma Hep-2 cells and to explore the effect of HIF-1α, GLUT-1 and VEGF as endogenous hypoxic markers on laryngeal carcinoma., Methods: The expression levels of HIF-1α, GLUT-1 and VEGF were detected in 35 cases of laryngeal carcinoma by SP immunohistochemical methods and in Hep-2 cells by SP immunocytochemical methods. The relationship between HIF-1α and GLUT-1, VEGF protein expression was analyzed., Results: Of the 35 cases, 16 cases expressed HIF-1α, 16 cases expressed GLUT-1, 19 cases expressed VEGF. The expression of HIF-1α and VEGF were closely correlated with pathologic grading and lymphnode metastasis. GLUT-1 was correlated with lymphnode metastasis. The expression levels of HIF-1α, GLUT-1 and VEGF in Hep-2 cells under hypoxic condition were higher than those under normoxic condition., Conclusion: HIF-1α may promote the expression of GLUT-1 and VEGF in laryngeal carcinoma, furthermore promote tumor angiogenesis, invasion, and metastasis of the laryngeal carcinoma.

Objective: To investigate the effects of hypoxia on the features and chemoresistance of cancer stem cells in Hep-2 cells and underlying mechanism., Methods: The shRNA interference recombinant plasmid targeting HIF-1α was synthesized and transfected into Hep-2 cells. The HIF-1α knockdown Hep-2 cells were established after clonal selection and the expression of HIF-1α was measured. The cellular features including proliferation, clonal formation, cell cycle, apoptosis and CD133 phenotype were measured in Hep-2 cells cultured under hypoxic condition in vitro. CD133+ cells were sorted from Hep-2 cells with flow cytometry. Clonal formation test and cisplatin treatment were carried out, and the expressions of related genes (Oct-4, suvivin and p53) in CD133+ cells were measured., Results: HIF-1α knockdown Hep-2 cells was successfully established, as evidenced by the reduced mRNA and protein expressions of HIF-1α. The Hep-2 cells cultured under hypoxic microenvironment showed higher proliferation and clonal formation activity, cell cycle arrest in G0/G1, lower apoptosis, up-regulated CD133, however the effects of hypoxia reduced in HIF-1α knockdown Hep-2 cells. CD133+ cells were successfully sorted from Hep-2 cells, and the CD133+ cells showed increased clonal formation activity and cisplatin treatment resistance in hypoxia. Also the effects of hypoxia on CD133+ cells decreased with HIF-1α knockdown, showing down-regulated Oct-4 and survivin and up-regulated p53., Conclusions: Hypoixa can induce the features of cancer stem cells in Hep-2 cells and increase proliferation, differentiation and chemoresistant ability of CD133+ cells, which might be correlated with the changes in expressions of HIF-1α and related genes regulated by HIF-1α.

Objective: To study whether laryngeal cancer stem cells in hypoxia have the characteristic of resistance to irradiation and underlying mechanism., Methods: CD133(+) cells were separated from Hep-2 cells with flow cytometry (FCM) and the purity was 92.8%. The separated CD133(+) cells were cultured in serum-free medium in hypoxia in normoxia environment respectively, and hypoxia-inducible factor 1 alpha (HIF-1α) expression was detected by FCM. The cells were exposed respectively to X-rays emitted by linear accelerator with a dose of 0, 5, 10, 15 or 20 Gy for 24 hours, with additional time points of 12, 36, and 48 hours for the cells exposed to 10 Gy. Then the growth inhibition ratios of cells in hypoxia and normoxia groups were detected with MTT assay at different time points. Soft agar colony formation assay was used to detect colony formation ratios of cells in hypoxia and normoxia groups. DNA dependent protein kinase catalytic subunit (DNA-PKcs), ataxia telangiectasia mutate (ATM), Survivin and P53 were detected by FCM., Results: Growth inhibition ratio of CD133(+) cells in hypoxia group was lower than that in normoxia group (P < 0.05). Colony formation ratio of CD133(+) cells was higher than that of CD133(-) cells (P < 0.01) and the ratio of CD133(+) cells in hypoxia group was higher than that in normoxia group (P < 0.05). The ratio of hypoxia group was not affected by irradiation, while the ratio of normoxia group decreased significantly after irradiation (P < 0.05). The expressions of DNA-PKcs, ATM, Survivin and P53 in CD133(+) cells were higher than those in CD133(-) cells respectively (P < 0.01). In CD133(+) cells with radiation, the expressions of DNA-PKcs and Survivin of hypoxia group were higher those of normoxia group (P < 0.05), but no difference in the expression of ATM or P53 between the two groups., Conclusions: Laryngeal cancer stem cells play an important role in radioresistance mediated by hypoxia.

Objective: To explore the clinical applications of reversed pedicled submental island flap in the face and oropharynx., Methods: The clinical data of ten cases of reconstruction of defect in the area of face or oropharynx following resection of tumors with reversed pedicled submental island flaps between January of 2004 to December of 2006 were retrospectively studied. The cases included six males and four females, aged from 24 to 76 (median 55 years). One of the cases suffered from upper lid melanoma, two hard palate myoepithelioma, one maxillary ameloblastoma, four tonsil cancer and two lingual carcinoma. The submental island flaps were dissected according to the area of the defection, the distal facial vessel was used as the pedicle of the flaps, and the flaps were transferred through under the skin of the face or the mandible to the area of the defection. Radical neck dissection was performed in the four tonsil cancers and two lingual carcinomas simultaneously., Results: All the flaps showed pale, edema and/or congestion after the surgical treatment, but swelling and congestion disappeared gradually 5 days later. One of the cases suffered from severe congestion of the flap, but the flap survived by stabbing with needle and draining. The flap of another case separated from the hard palate was sutured again, and healed. Lower lip palsy occurred in another case, and recovered 3 months later by conservative therapy. None of the flaps necrosed., Conclusions: Because of the upper pedicle, reversed pedicled submental island flap can be transferred to a long distance to reconstruct the defect in the upper face or around the orbit, and radical neck dissection can be performed simultaneously, it is a reasonable candidate in repairing the defect of the face and oropharynx.