A comparative study of the static and dynamic response of a slope is carried out, using the large deformation theory of the updated Lagrangian formulation and the conventional infinitesimal theory. In the static analysis, a strength reduction method proposed by one of the authors is used to evaluate the safety factor of the slope. It is found that by the large deformation theory, the safety factor is larger than that calculated by the infinitesimal theory, and this difference becomes large along with the reduction of elastic modulus. In the dynamic analysis, it is observed that the large deformation theory gives smaller sliding displacement and larger response acceleration than the infinitesimal approach. It is concluded that in many cases the large deformation approach gives more adequate solutions.

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(

3H

) Tobramycin was used as a probe to determine the relationship between the structure of aminoglycoside antibiotics and their ability to remove this drug from its higher affinity binding site on the ribosome. The dissacharide moieties (neamine, tobramine, gentamine) appeared to have a common binding site, whereas the kanosamine, garosamine and ribose moieties determined the specificity of this binding. Amikacin and butikacin behaved in an anomalous manner in spite of their close structural relationship to tobramycin.

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The activities of tobramycin derivatives acetylated and ethylated on the '-N, '-N and -N positions were examined. The MICs of these derivatives against tobramycin sensitive strains indicated that '-N-ethylated and '-N-ethylated derivatives have a fairly good activity, and confirmed that the -N position is the most important one for antibiotic activity since -N derivatives were less active. The MICs of these derivatives against tobramycin resistant strains, and their inactivation by tobramycin modifying enzymes were examined. These results showed that '-N or '-N ethylation protects the drug against inactivation by AAC(') or AAC('), respectively, and '-N-ethyltobramycin and '-N-ethyltobramycin were active against strains containing these modifying enzymes. On the other hand, -N ethylation protects the drug against inactivation by AAC() but -N-ethyl tobramycin does not inhibit strains containing this enzyme.

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Based on the concept "intermediate soil wedge" which is dependent on mobilized frictional resistance, a new theory has been developed for evaluating the seismic earth pressures against retaining walls under any condition between the active and passive states. For this theory, the seismic earth pressure is separated into four components according to their formation. New equations are proposed to determine the distribution, resultant and point of application for each component. An equivalent seismic coefficient is introduced to take into account non-uniform seismic acceleration distribution with depth. The equations place special emphasis on dependence of the seismic earth pressure on mode and level of wall movement. The equations can be reduced to the Mononobe-Okabe equation for the limiting conditions. Their applicability was confirmed by comparing the predictions with a number of previous model test results.

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A finite element model capable of taking into account nonlinear hysteretic soil behavior is presented to study earthquake induced retaining wall movement. The model also accounts for increase in lateral stresses and settlement associated with grain slip caused by cyclic loads. The predictive capability of the proposed method is verified by comparing responses given by the model with those computed by another existing finite element model and also with responses recorded at the Cambridge centrifuge facility. The study reveals that the wall displacement can be substantially affected, among other factors, by the increase in lateral stresses due to grain slip and wall-soil friction. Care should be taken when selecting a constant value of wall-soil friction angle for the entire duration of excitation since structural changes can occur in the soil adjacent to the wall.

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The mechanism of wave-induced instability in a permeable seabed have been studied for more than two decades. The distinction between shear failure and liquefaction, however, has not been clearly defined. This paper presents a fundamental study on the differences in two failure modes for a fully saturated seabed of both finite and infinite thickness. The wave-induced effective stresses and pore pressure, obtained from an analytical solution of Biot's pore-elastic consolidation theory, were employed to examine the failure modes under a two-dimensional plane strain condition. A case study is presented to examine the failure modes with respect to several parameters, such as excess pore pressure, seepage flow, seepage force, failure areas and stress path in the seabed. The conclusions obtained from this study were as follows ; (1) the thickness of a permeable seabed affects the pore pressure and effective stress response to ocean waves and the failure mode of the seabed, () either a liquefaction or shear failure, or both, occur in the seabed, even in the saturated seabed, () the Mohr-Coulomb's failure criterion, when combined with elastic stresses, can not be employed to estimate the liquefaction failure in the seabed, (4) the liquefaction can be evaluated by a criterion in terms of the excess pore pressure, () The liquefied zone in the seabed is significantly different from the shear failure zone. The shape beneath the seabed surface for the former is almost identical to the contour where the upward seepage flow is concentrated.

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An analytical measure was developed so that the permanent displacement/deformation caused by seismic subsoil liquefaction can be predicted. Since the effects of topography on displacement is important, a three-dimensional analysis was developed which can fully consider the topography. Moreover, the loss of resistance in the surface unliquefied crust undergoing a tensile stress was taken into account. The empirical interpolation of the lateral displacement along the vertical axis helped reduce the amount of computation. Consequently, a finite-element two-dimensional analysis which is equivalent to a three-dimensional calculation was developed. The displacement obtained by the proposed method is the maximum possible to minimize the potential energy of the subsoil. By comparing the calculated displacement with the observation, the predicted displacement was to some extent greater than the observation. Hence, a dynamic analysis in the time domain, which was also developed by the authors, is necessary for a better matching between prediction and observation. In contrast, the direction of displacement was correctly predicted by the present analysis.

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We previously reported human papillomavirus type 52 (HPV52) as the most prevalent high-risk genotype in non-cancer individuals in Vietnam. This study aimed to evaluate HPV genotypes and HPV16

and (/) gene variations in Vietnamese patients with genital cancers. Biopsy samples were collected from 124 Vietnamese patients with genital cancers (20 with vaginal, 50 with vulvar, and 54 with penile cancer). The HPV-DNA was amplified and genotyped, and HPV16 / genes were compared with those previously reported for women with normal cervical cytology (N = 23). HPV-DNA was detected in 80.% (100/124) of the cancer patients (80.0% of vaginal, .0% of vulvar, and 79.% of penile), with HPV16/18 in .0% (/100) and HPV52 in .0% (/100) of the HPV-positive samples. The HPV-DNA prevalence and HPV genotype distribution did not significantly differ among the genital cancer patients (both P = 0.). Significantly fewer instances of the HPV16 A4 sublineage (34.% vs. .%, P < 0.0001) and HPV16 29S (36.4% vs. .0%, P = 0.0002) occurred in the cancer patients than in the women with normal cytology. Our results indicate that HPV16/18 accounts for more than 85% of genital cancers in Vietnam, and the HPV16 sublineage A4 containing 29S may be less oncogenic.

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During earthquakes, saturated loose sandy soils often liquefy, causing serious damage to buildings and underground structures. Various construction methods have been employed to stabilize these soils against liquefaction. The popular methods are those which increase their density. Vibration and impact methods are commonly employed, but these often pose a problem of noise and vibration in urban areas. Results of previous experiments have shown that Quick Lime Consolidated Briquettes (QCB), a soil stabilizer made of quicklime and cement placed to form cylinders, significantly increases resistance to liquefaction by utilizing the effects of water absorption, swelling, and hardening. In the present study, shaking table tests were performed to evaluate the earthquake resistance of soil treated with QCB. Results of these test showed that the response acceleration and excess pore water pressure in QCB-treated soils were scarcely affected by the excitation of 200 Gals. The soil settlement due to shaking was about one tenth of that for the untreated soil, proving the effectiveness of QCB during earthquakes.

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The objective of this article is to propose and evaluate a sliding-block model to deal with very large displacements of slopes when a horizontal earthquake is applied. The slip surface consists of two inclinations on which full shear resistance is mobilized. Internal shearing exists along a sub-plane that intersects the angle between the two sub-planes that form the external slip surface. The ratio of the distance moved along the two external sub-planes depends on the inclination of the internal sub-plane. If there is a water table line, undrained conditions are assumed during motion and total stress analysis is performed. The governing equations of motion are formulated, analytical solutions are obtained for some cases, and back-analysis of four well-documented slides is performed.

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This paper is concerned with an extension of a rotational limit equilibrium method for determining the permanent displacements of slopes under seismic excitation. In the proposed procedure, the sliding mass is treated as a rigid rotating body defined by a log spiral trace. Permanent displacements are obtained by double-integration of the equation of motion in a manner similar to Newmark's translational sliding block method. The seismic slope stability analysis is based on the rotational (variational) limit equilibrium approach. This stability analysis was verified with dynamic experimental results obtained from centrifuge model testing. A series of parametric studies was conducted on"unstable"slopes, investigating the effects of soil properties and characteristics of excitation on the magnitude of permanent displacements. The higher the frictional angle, the smaller the permanent displacement of the slope is. Low excitation frequency yields larger slope displacement if the excitation is extended for the same time period of time. The effect of frequency becomes less distinct when a larger value of yield seismic coefficient is used. The proposed procedures produce a rational criterion to evaluate the seismic performance of simple slopes. This criterion is based on permanent displacement limit rather than factor of safety alone.

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This paper introduces a time-dependent radiation damping for the time-domain wave equation analyses of single piles. By deriving the radiation damping ratios of the linear viscoelastic soils along the pile from the dynamic impedance functions (Novak, 1974), time-dependent damping coefficients are obtained from the inverse Fourier Transform of these damping ratios and the static soil spring constants. Numerical examples are studied by solving the wave equations with the finite difference scheme. Applications of the modeling are presented and discussed with emphasis on identifying the primary factors that control the performance of piles. It is important to know that this solution, in contrast to the ordinary frequency-domain approach, can predict the softening load-displacement response of the piles under cyclic loads. The pile response under monotonic loads would be significantly influenced by the proposed damping parameters.

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The paper discusses the main aspects involved in numerical modeling of successive, large deformation, rigid body impacts in sand. The modeling was performed for the study of dynamic compaction of dry sand induced by repeated drops of a rigid tamper. Two dynamic finite element codes were used with a variety of soil models and computational algorithms. Large deformation effects and associated plastic behavior of the sand required special computational techniques of remeshing and reassignment of material properties. Consistency and stability of the formulations were evaluated based on their characteristics of convergency, accuracy, and computational efficiency. The adequacy of these models to represent actual soil behavior was evaluated by comparing computed results with available experimental data from an extensive laboratory investigation. The conclusions presented may serve as general guidelines relevant for this type of analysis.

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The syntheses of (S)-13-hydroxy-(, 4, )-tetradecatrienoic acid (1) and (, 4, Z-tetradecatrienoic acid () were carried out by using the Wittig reaction as the key step. The asymmetric center at C-13 and the double bond between C- and C-9 for natural compound 1 were reconfirmed as being of (S) configuration and , respectively. The relationship between the structure of the unsaturated hydroxy fatty acids and their inhibitory effect on the growth of lettuce was investigated.

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