• Biomolecules & Therapeutics
• /
• v.7 no.4
• /
• pp.329-334
• /
• 1999

Recently, cellular signal transduction mechanisms are greatly understood. However, bone cell signaling is not completely characterized. Interestingly, bone cells synthesize a number of growth factors such as IGF-I PDGF, IGF-II etc., suggesting these growth factors play important roles in bone cell signaling. In the present study, potential roles of nitric oxide (NO) and protein kinases in osteoblast signal transduction are proposed.

• Proceedings of the IEEK Conference
• /
• 1999.06a
• /
• pp.683-686
• /
• 1999

In this paper, we develop an active sonar signal synthesis model to analyze the detection performance of active sonar systems in a shallow water environment. Using this model, we synthesize the return signal of a bistatic sonar system at a typical operating frequency. This signal can be used to test proper active sonar signal processing techniques for real applications.

• Korean Journal of Microbiology
• /
• v.8 no.1
• /
• pp.35-40
• /
• 1970

In the cell-free systems of Dunaliella tertiolecta, fructosediphosphate aldolase hardly contribute to synthesize hexosephosphate from triosephosphate derived from pentosphosphate pathway, and it could be considered that glycerol synthesized from added glucose was synthesized but via 3-phosphoglyceraldehyde as an intermediate not hydroxypyruvate.

• Bulletin of the Korean Chemical Society
• /
• v.20 no.1
• /
• pp.53-58
• /
• 1999

We synthesize the spinel lithium manganese oxides of the LiCrxMn2-xO4 from x=0.00 to 0.70 at 750 ℃ in air and identifiy them with X-ray crystallography.

• YAKHAK HOEJI
• /
• v.28 no.1
• /
• pp.17-20
• /
• 1984

Synthetic procedures to synthesize fenbufen-acetaminophen ester were searched by acid chloride method, DCC method and mixed acid anhydride method. The compound was synthesized by DCC method and mixed acid anhydride method but could not be synthesized by acid chloride method. Its anti-inflammatory activity was superior to acetaminophen and similar to fenbufen.

• Journal of Power Electronics
• /
• v.15 no.3
• /
• pp.670-684
• /
• 2015

The hybrid cascaded multilevel inverter (HCMLI) is a popular converter topology that is being increasingly used in high power medium voltage drives. The intricacy of the control technique for a HCMLI increases with the number of levels and due to fluctuating dc voltages. This paper presents a novel offline quadrant search based space vector modulation technique to synthesize a sinusoidal output from a dispersed pattern of voltage vectors due to different voltages in the auxiliary unit. Such an investigation has never been reported in the literature and it is being attempted for the first time. The method suggested distributes the voltage vectors for a reduced total harmonic distortion at minimal computation. In addition, the proposed algorithm determines the maximum modulation index in the linear modulation range in order to synthesize a sinusoidal output for both normal and abnormal vector patterns. It is better suited for a wide range of practical applications. It is particularly well suited for renewable source fed inverters which utilize large capacitor banks to maintain the dc link, which are prone to such slow fluctuations. The proposed quadrant search space vector modulation technique is simulated using MATLAB/SIMULINK and implemented using a Nexys-2 Spartan-3E FPGA for a developed prototype.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.10
• /
• pp.3343-3348
• /
• 2012

The possible ways for increasing the antioxidant properties of vitamin E have been investigated with density function theory. The effect of replacing three methyl groups of vitamin E with various substituents such as electron donating and electron withdrawing groups on the antioxidant properties of vitamin E were investigated. Also the effects of the reducing the number of atoms in the heterocyclic ring and replacing the oxygen heteroatom with other heteroatoms on the antioxidant properties of vitamin E were investigated. The novel structures that obtained from replacing methyl groups with substituents such as $NH_2$, OH, COOH and NHMe have greater antioxidant activity than vitamin E. Obtained results reveal that novel structure that obtained with replacing O with NH hetroatom would be a better antioxidant than vitamin E. The results reveal that reducing the number of atoms in the heterocyclic ring is a better way to synthesize novel antioxidants.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.10
• /
• pp.3196-3202
• /
• 2012

Post-synthesis is used to synthesize organic hybrid inorganic mesoporous sieves. In this method, the activity and structure of the base sieve are crucial to obtain the definable hybrid materials. The chemical and physical properties of the base can be largely changed either by the final step of its synthesizing processes, by template removal which is accomplished with the oxidative thermal decomposition (burning) method or by solvent extraction method. In this paper we compared two methods for the post-synthesis of organic hybrid MCM-48. When the template was extracted with HCl/alcohol mixture, the final product showed larger pore size, larger pore volume and better crystallinity compared to the case of the thermal decomposition. The reactivity of the surface silanol group of template free MCM-48 was also checked with an alkylsilylation reagent $CH_2=CHSi(OC_2H_5)_3$. Raman and $^{29}Si$ NMR spectra of MCM-48 in the test reaction indicated that more of the organic group was grafted to the surface of the sample after the template was removed with the solvent extraction method. Direct synthesis of vinyl-MCM-48 was also investigated and its characteristics were compared with the case of post-synthesis. From the results, it was suggested that the structure and chemical reactivity can be maintained in the solvent extraction method and that organic grafting after the solvent extraction can be a good candidate to synthesize a definable hybrid porous material.

• Korean Journal of Materials Research
• /
• v.24 no.12
• /
• pp.700-703
• /
• 2014

Calcium phosphate minerals are biologically important because of their application in the fields of orthopaedics and dentistry. Herein we have tried to synthesize calcium phosphate minerals from biowaste clam shells. A simple microwave method was used to synthesize a mixture of calcium phosphate minerals such as hydroxyapatite, tri-calcium phosphate, and monetite. The microwave induces vibration of the dipole ions in the reagent. The heating and rearrangement of ions and atoms occurs during the process. The phases obtained in the final powder were ascertained by X-ray diffraction; the morphology of each sample was checked using a scanning electron microscope. We were able to obtain a mixture of calcium phosphate minerals using the microwave method; the calcined powder showed a brick like morphology, which is different from the rod shape morphology of the hydroxyapatite obtained using the hydrothermal process.

• Journal of Satellite, Information and Communications
• /
• v.6 no.1
• /
• pp.12-18
• /
• 2011

Signal fading due to rain is one of the most significant factors degrading link quality in satellite communication systems. Adaptive transmission is considered to be the most efficient means to countermeasure the rain attenuation. In order to develop and design a good adaptive transmission system, we need a dynamic rain attenuation model which can synthesize time series of rain attenuation. In this paper, we present a modeling technique for dynamic rain attenuation using a Markov process. We derive statistical fading properties of the rain attenuation data measured in second time interval and define four states in the Markov process. We synthesize the rain attenuation data using the 4-state Markov process, and compare statistical properties of the simulated data to those of the measured data.