A sample of [

3H

] tobrarnycin (5, 000 Ci/Mole) has been synthetized and incubated with
the bacterial ribosome and its subunits. The results obtained show that this antibiotic has
two types of binding sites. The primary one is probably responsible for the inhibition of
protein synthesis whereas the secondary one is probably related to the misreading and reading
tiirough of the messenger RNA.

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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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This paper is concerned with dynamics of the standard penetration test (SPT). The usefulness of mounting strain gages at two different stations along a driven rod is described, together with a workable procedure of analysis. The analysis procedure makes use of the traveling time between the two gage points and enables one to identify the particle velocity, the displacement and the stress at any station of the rod, as well as the energy actually transmitted from a hammer to the rod. Particular attention is called for the consequence of inevitable, small errors in strain data upon such identifications. A pertinent procedure of error-correction is proposed and its validity is substantiated against the performance of well instrumented SPTs performed by the authors.

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The activities of tobramycin derivatives acetylated and ethylated on the 6'-N, 2'-N and -N positions were examined. The MICs of these derivatives against tobramycin sensitive strains indicated that 2'-N-ethylated and 6'-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 2'-N or 6'-N ethylation protects the drug against inactivation by AAC(2') or AAC(6'), respectively, and 2'-N-ethyltobramycin and 6'-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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The Gujarat earthquake in India occurred in January, 2001, and caused significant damage in the province of Gujarat. The Japanese Geotechnical Society sent a small reconnaissance team to the damaged region after the quake. The present text presents the report from this activity. The major attention of the team was focused on geotechnical aspects of the damage which were related to earthfill dams and harbor land fills. It was found that a significant portion of damage was concentrated in fills resting on soft natural soils. Swedish weight soundings which were conducted at two places demonstrated the existence of such a soft subsoil. From this, it was concluded that amplification of earthquake shaking as well as the permanent deformation in the soft foundation soil induced such kinds of damage as subsidence, cracking, and lateral spreading in overlying artificial fills. For the better seismic resistance of those affected fills during future earthquakes, the improvement of soft subsoil seems essential.

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The boundary element method expanded in frequency domains is presented to analyze the dynamic interaction between an embedded flexible rectangular foundation and soil with consideration of the obliquely incident waves. Numerical results describing the influence of the flexibility of the foundation on the dynamic responses of the foundation due to obliquely incident waves indicate that the flexibility of actual foundations can diminish the reduction of translation responses and increase the rotational responses in the high frequency range. These phenomena are more conspicuous as the embedment ratio is larger and the value of the wave velocity ratio of the soil and the foundation approaches to unity. When the high frequency components of the input ground motion are important and the basement has higher flexibility (for example ₂v_s/₁v_s >0.4), the analysis method which considers the basement as a rigid foundation may lead to unsafety estimations and the estimation of the flexibility of the foundation is necessary as analysing the effective input motion with consideration of the incident waves.

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Elastic wave propagation in saturated soil is investigated in order to grasp the frequency dependent wave propagation property of actual soil. First, a closed form solution of Biot's equation is derived under a one-directional wave propagation condition. Then, the frequency dependent properties of waves in various soils such as clay, silt, sand, gravel and soft rock are computed and discussed. The behavior is shown to be classified into three states : low frequency, high frequency and transient. Properties hardly change in the low and high frequency states. The degree of saturation is shown to hardly affect the shear wave property, but it greatly affects the dilatational wave property, especially in a highly saturated condition. Permeability hardly affects the properties at low and high frequency states, but it does change the frequency range of the transient state. Next, the applicability of Biot's formulation is examined and the high frequency state derived from Biot's equation is shown to be valid when permeability is larger than that of silt. Finally, it is shown that various mechanical properties can be evaluated using the frequency dependent characteristics of the wave, some of which are difficult to measure in situ with conventional tools.

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A series of shaking table tests are made to investigate the uplift behavior of sewer pipes caused by liquefaction of surrounding soil. It is shown that uplift displacement of pipes buried in unliquefiable original soil, which does not allow a dissipation of excess pore water pressure from liquefied backfill soil, increases drastically when they are subjected to extensive shaking. Uplift displacement of pipes buried in liquefiable original soil, on the other hand, accumulates rather gradually even at moderate shaking. A different behavior on residual deformation of the backfill and the original soils is also observed. In relation to the effects of soil condition, damage to sewer pipes in Towada City caused by the December 28, 1994 Sanriku-Haruka-Oki earthquake is reported and discussed. It is estimated that upper backfill soil consisting of sandy gravel may have liquefied because it was under loose and saturated condition and was subjected to earthquake motion under nearly undrained condition due partly to its own low permeability and also to the existence of surrounding original soil with low permeability.

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During past earthquakes, several types of underground structure were damaged by uplift movement, because they were relatively light compared with the buoyancy force resulting from liquefaction of the adjacent subsoil by earthquake. To investigate this uplift behavior, a variety of model tests were conducted. In these tests, the uplift of underground structures was caused by both nearly instantaneous deformation of a surrounding subsoil layer and gradual movement of a pore fluid, while reconsolidation of liquefied soil resulted in settlement of the structure. Several different effects of structure type on uplift behavior were observed, including reduction of excess pore water pressure in a soil layer overlying completely-buried box structures and three dimensional deformation of the backfill soil surrounding a manhole together with deformation of original soils thus "squeezing" the backfill soil into the space occupied by the manhole. Analysis of the test results suggests that a safety factor against uplift, which was defined based on the equilibrium of vertical force acting on the structure, can be used to evaluate the triggering of uplift.

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During the 1993 Kushiro-Oki Earthquake, several sewer manholes in Kushiro Town were ejected up to 1.5m. In order to evaluate their failure mechanism, level and boring surveys, cut-off investigation and laboratory tests were carried out. It was estimated that the backfill soil which liquefied extensively moved laterally toward the bottom of the ejected manholes. Possible influences of the original subsoil on the uplift displacement are discussed together with the applicability of safety factor against uplift.

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Realization of a -D TV system using the present day HDTV is proposed. This system is based on the stereoscopic principles transmitting the left and right eye view images of the object on multiplexed video lines. In the receiver, the video lines are demultiplexed, the missing lines are interpolated and the stereo pair of images are reconstructed in two picture tubes. By means of a bicircularily polarized viewing system, these stereo pair of images are made to offer a true -D vision. This system takes the advantage of high resolution offered by teh HDTV system and at the same time adds only a minimal complexity to the circuitry of the HDTV transmitter and the receiver for converting the HDTV into -D TV.

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The evidence of earth structure damages due to earthquakes and the need for study on relatively dense and unsaturated earth structures such as river dikes and road embankments motivated this research work. A series of shake table tests were performed in order to provide the needed experimental data for this study. During the experimental program, two types of soils, i.. Toyoura sand and a sample from natural deposits of sandy material were used. A rectangular laminar box was mounted over a rigidly fabricated slope and subjected to horizontal shaking. Sweep tests and Swedish sounding tests were also performed in order to measure the material properties. The results of these tests show the effect of different parameters such as amplitude of cyclic loading, number of cycles, initial static shear stress, confining pressure and shear stress history (loading-unloading, over-consolidation and creep time) on shear deformation of unsaturated slopes during and after cyclic loading. The outcomes of the test results are used as a basis to develop a new single degree of freedom model of mass and nonlinear spring over a slope. Stress-strain behavior of the soil is defined as a nonlinear stiffness function of a spring. Time dependent input acceleration is considered as the base excitation and the induced inertia force is superimposed on the initial static shear stress. The numerical solution of the equation of motion of the model predicted the residual deformation of the system at the end of shaking. Several cases were analyzed and compared with the test results.

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A conventional direct shear apparatus was modified to provide drained simple shear mode during cyclic loading. Several tests were performed in order to investigate the seismically induced deformation, stress-strain behavior and cyclic residual shear deformation of unsaturated and relatively dense sandy earth structures. This paper reports the effects of different parameters such as number of cycles, initial static shear stress, soil type, degree of compaction, consolidation time and stress, creep time and aging, amplitude of harmonic and irregular cyclic loading and loading rate on the cyclic stress-strain behavior and residual deformation accumulation of the samples. Based on the test results, concepts of Masing's rule are modified to model the stress-strain behavior of the material during the cyclic simple shear.

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The curvatures and subsequent bending imposed to piles by the surrounding soil during the passage of seismic waves is studied. This type of bending develops even in the absence of a superstructure and is referred to as "kinematic" bending, to distinguish it from pile bending generated from inertia forces in the superstructure (termed "inertial" bending). Although kinematic bending may be severe in the presence of sharp stiffness discontinuities in the profile and may lead to damage, it has received little attention by engineers. The scope of this paper is threefold : (1) to review some existing design methods ; (2) to present an improved analytical model for estimating kinematic pile bending moments at an interface between two thick soil layers under dynamic SH-wave excitation ; and () to propose a simplified analysis procedure to be used for designing piles against kinematic loading. To this end, a dimensionless bending strain parameter (instead of the commonly-used bending moment) and a strain transmissibility function relating pile bending strain and corresponding soil shear strain are introduced. The two indices provide insight into the physics of the problem which is often obscured by the use of bending moments. Results from the model are in good agreement with more rigorous solutions. Numerical examples are presented.

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