• BMB Reports
• /
• v.42 no.10
• /
• pp.623-630
• /
• 2009

Hsp90, an evolutionarily conserved molecular chaperone, is involved in the folding, stabilization, activation, and assembly of a wide range of 'client' proteins, thus playing a central role in many biological processes. Especially, several oncoproteins act as Hsp90 client proteins and tumor cells require higher Hsp90 activity than normal cells to maintain their malignancy. For this reason, Hsp90 has emerged as a promising target for anti-cancer drug development. It is still largely unknown how Hsp90 can recognize structurally unrelated client proteins. However, recent progress in structural studies on Hsp90 and its interaction with various co-chaperones has broadened our knowledge of how the Hsp90 ATPase activity, which is essential for its chaperone function, is regulated and coupled with the conformational changes of Hsp90 dimer. This review focuses on the roles of various Hsp90 co-chaperones in the regulation of the Hsp90 ATPase cycle, as well as in the selection of client proteins. In addition, the current development of Hsp90 inhibitors based on the structural information will be discussed.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2001.04a
• /
• pp.53-60
• /
• 2001

Meshfree methods have been attracting issue as computational methods during past a few years. Nowadays, various meshfree methods such as EFGM, RKPM h-p cloud method and etc. were developed and applied in engineering problems. But, most of them were not truly meshless method because background mesh of cell was required for the spatial integration of a weak form. A nodal integration is required for truly meshless methods but it is known that this method gives a little unstable and incorrect solutions. In this paper, an improvement scheme of the existed nodal integration which the weak form can be simply integrated without any stabilization term is proposed. Numerical tests show that the proposed method is more convenient and gives more correct solutions than the previous method.

• Structural Monitoring and Maintenance
• /
• v.6 no.4
• /
• pp.347-364
• /
• 2019

Two seismic response data from the CSMIP strong motion instrumentation of Pacoima dam are selected: San Fernando earthquake (Jan 13, 2001; ML=4.3) and Newhall earthquake (Sept. 1, 2011; ML=4.2), for the identification of the dam system. To consider the spatially nonuniform input ground motion along the dam abutment, the subspace identification technique with multiple-input and multiple-output is used to extract the dynamic behavior of the dam-reservoir interaction system. It is observed that the dam-reservoir interaction is significant from the identification of San Fernando earthquake data. The influence of added mass (from the reservoir) during strong ground motion will create a tuned-mass damper phenomenon on the dam body. The fundamental frequency of the dam will be tuned to two different frequencies but with the same mode shapes. As for the small earthquake event, the dam-reservoir interaction is insignificant.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1997.04a
• /
• pp.152-159
• /
• 1997

This unit - structure of truss stabilized by cable tension is composed of four truss member adding to a central post and eight cables, and is connected by hinge joints and is stabilized by cable tension. As this unit - structures itself is a statically closed and stabilize system individually, it can be employed to assemble a structure with a variety of configuration. In this paper, for determination the shape of the unit - structure of truss stabilized by the cable, characteristics such as the stabilized range of the various geometrical parameter about unit system and the relation of the best governing paramter is demonstrated, and the relation of the results is compared in the range for the stabilization of unit-structure.

• Structural Engineering and Mechanics
• /
• v.5 no.6
• /
• pp.785-801
• /
• 1997

Reinforced Concrete beams with tension and compression softening material constitutive laws are studied. Energy-based and non-local regularisation techniques are presented and applied to a R.C. element. The element characteristics (sectional tangent stiffness matrix, element tangent stiffness matrix restoring forces) are directly derived from their symbolic expressions through numerical integration. In this way the same spatial grid allows us to obtain a non-local strain estimate and also to sample the contributions to the element stiffness matrix. Three examples show the spurious behaviors due to the strain localization and the stabilization effects given by the regularisation techniques, both in the case of tension and compression softening. The possibility to overestimate the ultimate load level when the non-local strain measure is applied to a non softening material is shown.

• Structural Engineering and Mechanics
• /
• v.72 no.1
• /
• pp.19-30
• /
• 2019

The mechanical behavior of Fiber Reinforced Cementitious Composites (FRCC) under direct shear is studied through experiment and analytical simulation. The cementitious composite considered contains 55% replacement of cement with fly ash and 2% (volume ratio) of short discontinuous synthetic fibers (in the form of mass reinforcement, comprising PVA - Polyvinyl Alcohol fibers). This class of cementitious materials exhibits ductility under tension with the formation of multiple fine cracks and significant delay of crack stabilization (i.e., localization of cracking at a single location). One of the behavioral parameters that concern structural design is the shear strength of this new type of fiber reinforced composites. This aspect was studied in the present work with the use of Push-off tests. The shear strength is then compared to the materials' tensile and splitting strength values.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.46 no.5
• /
• pp.419-426
• /
• 2018

For an orbit transfer in a space exploration mission, a solid or liquid rocket booster is included at the last stage of the launch vehicle. During the orbit transfer, thrust misalignment can cause a severe orbit error. Three axis attitude control or spin stabilization can be implemented to minimize the error. Spin stabilization technique has advantages in structural simplicity and lightness. One of ways to apply the spin stabilization to the payload is to include a spin table system in the launch vehicle. In this paper, effect of the spin table system on separation dynamics of the payload is analyzed. Simple model of the spin table to mimic basic functions is designed and simulation environment is established with the model. Effect of the spin table is tested by evaluating separation dynamics of a payload with and without the spin table. Analysis on tolerance effect of separation spring constant on separation dynamics of a payload is conducted.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.19 no.3
• /
• pp.130-138
• /
• 2015

In this study, to examine the application of cast-in-place of high-flowable and high-strength concrete, an experimental study on the lateral pressure of a formwork was preformed. The experiment specimens, which have different casting height and casting speed were prepared. The lateral pressure and the change of temperature from test specimens were obtained. The maximum lateral pressure was shown to lateral pressure of fresh concrete. Immediately after placing, the lateral pressure starts to decrease and, after 12 hours, it showed a stabilization. The decreased tend of the lateral pressure was similar with normal-strength concrete, which appears stabilization after 3~4 hours from casting completion. The more casting speed is fast, the more maximum lateral pressure is high, but pressure reduction with the lapse of time was nearly similar. In addition, it was found that there was no direct relation between the hydration heat and the lateral pressure reduction.

• Journal of the Korean Chemical Society
• /
• v.29 no.5
• /
• pp.533-538
• /
• 1985

To investigate the importance of the hydrophobic interaction in the spermine-induced collapse of DNA to a compact structure, the effect of urea on the anomalous absorbance-temperature profile of calf thymus DNA has been investigated. With the increase of the urea concentration, the trough phase of the anomalous absorbance-temperature profile was eliminated eventually. The cooperativity, enthalpy, and the midpoint of the transition to the trough region are more sensitive to urea than those of the Tm-region transition. The present data of the adverse effect of urea, a hydrophobic environmental reagent, on the thermal stabilization of the condensed state of DNA, suggest that hydrophobic interaction may play an important role in the stabilization of the tertiary structure of the collapsed state of DNA.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.9
• /
• pp.1457-1466
• /
• 2018

In the present study, the stabilizing effect of four different biological osmolytes on Bacillus licheniformis ${\gamma}$-glutamyl transpeptidase (BlGGT) was investigated. BlGGT appeared to be stable under temperatures below $40^{\circ}C$, but the enzyme retained less than 10% of its activity at $60^{\circ}C$. The tested osmolytes exhibited different degrees of effectiveness against temperature inactivation of BlGGT, and sucrose was found to be the most effective among these. The use of circular dichroism spectroscopy for studying the secondary structure of BlGGT revealed that the temperature-induced conformational change of the protein molecule could be prevented by the osmolytes. Consistently, the molecular structure of the enzyme was essentially conserved by the osmolytes at elevated temperatures as monitored by fluorescence spectroscopy. Sucrose was further observed to counteract guanidine hydrochloride (GdnHCl)-and urea-induced denaturation of BlGGT. Taken together, we observed evidently that some well-known biological osmolytes, especially sucrose, make a dominant contribution to the structural stabilization of BlGTT.