(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 3-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 3-N position is the most important one for antibiotic activity since 3-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, 3-N ethylation protects the drug against inactivation by AAC(3) but 3-N-ethyl tobramycin does not inhibit strains containing this enzyme.

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Two new polyacetylene compounds (, , 12)-1-acetoxy-3-isovaleryloxytetradeca-, , 12-trien-, 10-diyn-14-ol (B), and (, , 12)-1-acetoxy-3-(-methylbutyryloxy)tetradeca-, , 12-trien-, 10-diyn-14-ol () have been isolated along with (, , 12)-1-acetoxy-3-senecioyloxytetradeca-, , 12-trien-, 10-diyn-14-ol (A) from Atractylodes Rhizome (Karabyakujutu). The structures of these compounds were determined on the basis of their spectral data.

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The Beckmann rearrangement of aliphatic ketone oximes, R(CHs)=NOH (R=Et (1); n-Pr (); iso-Pr (3); iso-Bu ()), with polyphosphoric acid (PPA), polyphosphate ester (PPE), and ester of phosphoric acid ( P-5 R) was carried out and migratory ratios ((a)/(b) in eq. (1)) were determined, The results are shown in Fig.1, , and 3, respectively.
In Fig.1 and , the migratory ratios decrease with reaction time and nearly approach to the ratios of anti-alkyl form/syn-alkylform in benzene(A1) or DMSO(A)except for (3) (See Table 1). From this fact, it has been found that PPA and PPE are inactive for isomerization of the oximes andanti-alkyl oximes rearrange faster than syn-alkyl ones. ln the case of (3), migratery ratios are smaller than Ai or A. As acetonitrile is detected by GLC, it is presumed that fission has been occurred simultaneously with rearrangement in anti-alkyl oxime (eq. (3)). In the case of P-5 R, all modes of the reaction arethe same as in above, except that the rate of fission is tnuch faster than that in PPA and PPE.
The reaction of anti-alkyl ketone oximes having a bulky grouphas been greatly influenced by the use of sterically demanding catalysts such asPPA, PPE, and P-5 R.

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This study was performed to clarify which factors affected damage to tame-ike (small embankment dams for irrigation) in Hokudan Town as a result of the January 17, 1995 Hyogoken-Nambu earthquake. Factors were assumed to be : Location (.g., Distance to Epicenter, etc.), Structure (.g., Angle to Nearest Fault, Embankment Volume, etc.), Soil Properties of Embankment, Geology of Dam Site and History (Era of Construction, Repaired, etc.). Multivariate statistical analyses were performed for documentary data (damaged : 181, undamaged : 328). Ordinary statistical analyses were conducted for the data investigated in situ for soil properties of the embankment. The results show that the factors causing damage to dam are : (1) Nearest Fault (Nojima, Mizukoshi and D), () Distance to Nearest Fault (less than 500 m), (3) Distance to Epicenter (approximately to 14 km, which almost agrees with the location of seismic intensity 7 JMA), () Elevation of Dam Site (higher than 100 m), (5) Embankment Volume (the greater the volume the more damage was caused), () Direction of Dam Axis (normal or diagonal to the epicenter or to nearest the fault), (7) Plan View of Dam Axis (3 or axes), () Surface Geology of Dam Site (non-cohesive soil type ground), () Era of Construction (prior to 1891) and (10) Soil Properties of Embankment (sand, not silty sand or gravel, penetration resistance that is 10% smaller than the undamaged dams).

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Circuit techniques to enhance the linearity of input-voltage-to-current (V/I) conversion and to increase the output impedance of a current source by compensating for the low intrinsic gain of a transistor were introduced to realize a high-frequency operational transconductance amplifier (OTA) for a low supply voltage using sub-100-nm CMOS processes. Applying these techniques, a MOS 7th-order Gm- linear-phase low-pass filter (LPF) was realized using a 65nm CMOS process. A simplified biquad LPF that can serve as a component of a 7th-order LPF was newly developed by replacing OTAs with resistors. As a result, the -3dB frequency bandwidth, group delay ripple, 3rd-order distortion, and 3rd-order input intercept point (IIP3) were 200MHz, .%, ≤ -55dB with a 100MHz input, and +10.3dBm, respectively, all with a ±0.1Vp-p input signal at each input terminal in the pseudodifferential configuration. The LPF including an output buffer dissipated 60mW in the case of a 1.V supply. Wide spurious-free dynamic range (SFDR) characteristics were confirmed up to high frequencies.

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By employing an undrained cyclic loading ring-shear apparatus, a series of tests to reproduce the dynamic behavior of the Nikawa landslide induced by the January 17, 1995 Hyogoken-Nambu earthquake, is conducted. The test sample is Osaka-group coarse sandy soil taken from the landslide. The initial stress condition acting on a soil element in the sliding surface is applied to the sample. Based on the seismic records monitored at the JR Takarazuka Station, the input seismic wave is synthesized to reproduce the seismic stress acting on the sliding surface. The test results show that the soil failed due to the dynamic loading of the earthquake. The most important results are the excess pore water pressure generation and the acceleration of shear displacement continuing after the main shock. Combined with the grain crushing at the shear zone and the volume reduction in the drained constant-speed ring-shear test, the mechanism of this landslide is interpreted as, shear displacement causing grain crushing in the shear zone and volume reduction, and then resulting in a localized liquefaction phenomenon, "sliding-surface liquefaction". This geotechnical simulation test provides a reasonable interpretation of this highly mobile landslide.

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This paper describes the results of two instrumented axial loading tests on large scale model stone columns, constructed similarly to the prototypes with a technique which employs ordinary pile driving equipment. Kaolin was used to simulate natural soil conditions. Pressure cells and electric piezometers were used to monitor lateral stresses and pore pressures respectively, during loading. A factual report of the data and a direct evaluation with respect to the load-deformation response and the mode of failure of the stone columns is provided. Two deformation models are examined : a triaxial specimen expanding laterally under compression and a skin friction pile. Furthermore, a trilinear load-settlement relation is proposed for design purposes, based directly upon the results of the model tests.

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Natural sedimentary clays exhibit ageing effects on their behaviour when subjected to both consolidation and shearing. Attempts to characterising the in-situ 'structure'of soft marine clays have been made in case studies performed in Ariake (Japan) and in Bangkok (Thailand), each showing a typical profile of aged clay-structure with depth reflecting its site-specific geological consolidation history. In each site, profiles of Atterberg limits, natural water content, overconsolidation ratio (OCR), quasi-elastic shear modulus G_max and the undrained shear strength c_u with depth were attained from various laboratory tests, together with the a comparable profile of quasi-elastic shear modulus from insitu seismic survey G_f. Quantitative assessment of the aged clay-structure was made by using two different measures, metastability index MI (G) and the soil constant reflecting structure S (Jamiolkowski et al., 1994). The profiles of MI (G) and the S-value with depth were both determined based on the corresponding G_max behaviour of the reconstituted sample. "Disturbance"of laboratory samples retrieved by using two different samplers (i.., Laval and Japanese thin-walled samplers) with two different sampling techniques (i.., pre-boring and displacement methods) was discussed. A new approach to estimate c_u"in the ground", termed by the authors the MILK (Metastability Index coupled with Laboratory K_o test) method, is proposed. A trial of the MILK-method is demonstrated in soft Bangkok clay, the texture of which is similar to "soft cheese".

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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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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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Chemical properties of ergosta-, , (14), -tetraen-3-one (1) were investigated. Though 1 is rather stable to acids or bases, it reacts easily with two moleculres of oxygen on irradiation with UV light to give , -epidioxy-14α-hydroperoxyergosta-, 7, -trien-3-one (), which is transformed successively to , 7α;, -diepoxy-14α-hydroperoxyergosta-, -dien-3-one (3) and 14α-hydroperoxy--hydroxyergosta-, 7, -triene-3, -dione () under these reaction conditions.

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