• Journal of the Korean Magnetic Resonance Society
• /
• v.18 no.1
• /
• pp.36-40
• /
• 2014

Predicting secondary structure of protein through assigned backbone chemical shifts has been used widely because of its convenience and flexibility. In spite of its usefulness, chemical shift based analysis has some defects including isotopic shifts and solvent interaction. Here, it is shown that corrected chemical shift analysis for secondary structure of protein. It is included chemical shift correction through consideration of deuterium isotopic effect and calculate chemical shift index using probability-based methods. Enhanced method was applied successfully to one of the proteins from Mycobacterium tuberculosis. It is suggested that correction of chemical shift analysis could increase accuracy of secondary structure prediction of protein and small molecule in solution.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.10
• /
• pp.2245-2248
• /
• 2009

This paper demonstrates room temperature chemical vapor deposition (RTCVD) for fabricating titania inverse opals. The colloidal crystals of monodisperse polymer latex spheres were used as a sacrificial template. Titania was deposited into the interstices between the colloidal spheres by altermate exposures to water and titanium tetrachloride (Ti$Cl_4$) vapors. The deposition was achieved under atmospheric pressure and at room temperature. Titania inverse opals were obtained by burning out the colloidal template at high temperatures. The filling fraction of titania was controlled by the number of deposition of Ti$Cl_4$ vapor. The morphology of inverse opals of titania were investigated. The optical reflection spectra revealed a photonic band gap and was used to estimate the refractive index of titania.

• Proceedings of the KSRS Conference
• /
• 2007.10a
• /
• pp.612-615
• /
• 2007

Water quality modelling is an ideal tool of simulating physical, chemical and biological changes occurring in water systems. It has been utilized in a number of GIS-based water quality management and analysis applications. However, there is a need of a decision making process to translate the modelling result into an understandable form thereby implement the modelling results to the real world. This paper outlines a new water quality index called the QUAL2E's water quality index (QWQI) based on the water quality modelling using QUAL2E. The development mainly includes four steps: variable selection, sub-index development, weight assignment and sub-index aggregation. An experiment of applying the index and GIS to the Sapgyo River in Korea was implemented. Different from other water quality indices for general water uses, the index is specifically used for the simulated water quality indicators. The index can provide a simple and easy-to-understand decision support. Furthermore, interfacing with GIS, the decision analysis can be performed within a spatial environment. However, more study needs to be made in the future including the improvement of aggregation function.

• Journal of KIISE:Databases
• /
• v.31 no.6
• /
• pp.641-649
• /
• 2004

The relationship between chemical structures and biological activities is researched briskly in the area of 'Medicinal Chemistry' At the base of these structure-based drug design tries, medicinal chemists search the existing drugs of similar chemical structure to target drug for the development of a new drug. Therefore, it is such necessary that an automatic system selects drug files that have a set of chemical moieties matching a user-defined query moiety. Substructure searching is the process of identifying a set of chemical moieties that match a specific query moiety. Testing for substructure searching was developed in the late 1950s. In graph theoretical terms, this problem corresponds to determining which graphs in a set are subgraph isomorphic to a specified query moiety. Testing for subgraph isomorphism has been proved, in the general case, to be an NP- complete problem. For the purpose of overcoming this difficulty, there were computational approaches. On the 1990s, a US patent has been granted on an atom-centered indexing scheme, used by the RS3 system; this has the virtue that the indexes generated can be searched by direct text comparison. This system is commercially used(http://www.acelrys.com/rs3). We define the RS3 system's drawback and present a new indexing scheme. The RS3 system treats substructure searching with substring matching by means of expressing chemical structure aspredefined strings. However, it has insufficient 'rerall' and 'precision‘ because it is impossible to index structures uniquely for same atom and same bond. To resolve this problem, we make the minimum-cost- spanning tree for one centered atom and describe a structure with paths per levels. Expressing 2D chemical structure into 1D a string has limit. Therefore, we break 2D chemical structure into 1D structure fragments. We present in this paper a new index technique to improve recall and precision surprisingly.

• Journal of Sericultural and Entomological Science
• /
• v.20 no.2
• /
• pp.20-25
• /
• 1978

Research on the hormones of insect has followed by the special opportunities and problems arising from pollution. Since then, the main frame of it has been energetically exploited by ligation, decapitation and so on. In the meanwhile, knowledge of the biochemistry of hormone action as well as other aspects of biochemistry in insects has been gradually disclosed. Since 1966, practical use of active analogs of the hormones has been also worked out as an insecticide and brought the features of it to the light. On the other hand, it is expected to afford the increase of silk productivity resulted from control of the fifth larval period by delaying normal development. With these regards, some of analogs have been tried to apply practically to the silkworm. One of them is "Manta" produced by Zoecon Chemical Company and it is presently used for the increase of silk productivity in Japan. Another one is "R-20458", not registered one, issued by Stuffer Chemical Company. It is still pending for the silkworm growth regulator For the possibility of practical use, two chemicals are tested on the increase of silk productivity by topical application and the obtained results are summarized as follows. 1. It is evident that the fifth larval period was extended by topical application of the tested chemicals "Manta"and "R-20458"at the fifth instar after 51 hours of the last ecdysis, ranging from 12 hours to one day, as compared to. the control 2. In survival rates, there is no significance at 5% level between control and treatments. It proved that there was no toxity to silkworm by topical aprication. 3. There is an increase of cocoon yield in both chemical treatments. It was resulted from increase of weight of single cocoon. "Manta"2.5ppm produced 22.2kg of cocoon. It is equal to 9% increase in index, as compared to that of control. In case of R-20458, the increasing rates were varied at the different concentration; 21.4kg of cocoon production with 5% increase at 5ppm, 20.9kg of it with 2% increase at 2.5ppm and 20.6kg of it with 1% increase at 1. 25ppm in index, respectively, as compared with that of control. 4. Percentage of cocoon shell was increased by topical application. In case of "Manta" 2.5ppm, it is 25.6% which is equal to 6% increase in index, as compared with that of control. For "R-20458", the increasing rates of percentage of cocoon shell were varied with the different level of chemical concentration. They are 25.0% of 4% increase at 2.5ppm, 24.9% of 3% increase at 1.25ppm and 24.7% of 3% increase at 5ppm. 15% increase was attained at "Manta" 2.5ppm in the weight of cocoon layer based on cocoon yield and percentage of cocoon shell in index, as compared with that of control. The rates for "R-20458"are 5% increase at 2.5ppm and 4% increase at 1. 25ppm in index.

• Journal of Environmental Health Sciences
• /
• v.47 no.2
• /
• pp.155-165
• /
• 2021

Objectives: Acute exposure to high concentrations of chemicals can occur when a chemical accident takes place. As such exposure can cause ongoing environmental pollution, such as in the soil and groundwater, there is a need for a tool that can assess health effects in the long term. The purpose of this study was assessing the health risks of residents living near a chemical accident site due to long-term exposure while considering the temporal concentration changes of the toxic chemicals leaked during the accident until their extinction in the environment using a multimedia environmental dynamics model. Methods: A health risk assessment was conducted on three cases of formaldehyde chemical accidents. In this study, health risk assessment was performed using a multimedia environmental dynamics model that considers the behavior of the atmosphere, soil, and water. In addition, the extinction period of formaldehyde in the environment was regarded as extinction in the environment when the concentration in the air and soil fell below the background concentration prior to the accident. The subjects of health risk assessment were classified into four groups according to age: 0-9 years old, 10-18 years old, 19-64 years old, and over 65 years old. Carcinogenic risk assessment by respiratory exposure and non-carcinogenic risk assessment by soil intake were conducted as well. Results: In the assessment of carcinogenic risk due to respiratory exposure, the excess carcinogenic risk did not exceed 1.0×10-6 in all three chemical accidents, so there was no health effect due to the formaldehyde chemical accident. As a result of the evaluation of non-carcinogenic risk due to soil intake, none of the three chemical accidents had a risk index of 1, so there was no health effect. For all three chemical accidents, the excess cancer risk and hazard index were the highest in the age group 0-9. Next, 10-18 years old, 65 years old or older, and 19-64 years old showed the highest risk. Conclusion: This study considers environmental changes after a chemical accident occurs and until the substance disappears from the environment. It also conducts a health risk assessment by reflecting the characteristics of the long-term persistence and concentration change over time. It is thought that it is of significance as a health risk assessment study reflecting the exposure characteristics of the accident substance for an actual chemical accident.

• Bulletin of the Korean Chemical Society
• /
• v.24 no.9
• /
• pp.1265-1268
• /
• 2003

The estimation of retention factors by correlation equations with physico-chmical properties maybe helpful in chromatographic work. The physico-chemical properties were water solubility (S), hydrophobicity (P), total energy ($E_t$), connectivity index 1 ($^1{\chi}$), hydrophilic-lipophlic balance (x) and hydrophilic surface area (h) of isoflavones. The retention factors were experimentally measured by RP-HPLC. Especially, the empirical regulations of water solubility and hydrophobicity were expressed in a linear form. The equation between retention factors and various physico-chemical properties of isoflavones was suggested as $k = a_0 + a_1\;log S + a_2log\;P^Q + a_3(E_t) + a_4(^1{\chi}) + a_5(x) + a_6(h)$, and the correlation coefficients estimated were relatively higher than 0.95. The empirical equations might be successfully used for a prediction of the various chromatographic characteristics of substances, with a similar chemical structure.

• Korean Chemical Engineering Research
• /
• v.53 no.6
• /
• pp.776-782
• /
• 2015

$TiO_2-SnO_2$ nanoparticles with an average diameter of 3~5 nm were synthesized by hydrolysis of titanium tetraisopropoxide (TTIP) and tin chloride to depress the photocatalytic activity of $TiO_2$ nanoparticles. Organic-inorganic hybrid coating solutions were prepared by reacting the $TiO_2-SnO_2$ nanoparticles with 3-glycidoxypropyl trimethoxysilane (GPTMS) by the sol-gel method. The hard coating films with high refractive index were obtained by curing thermally at $120^{\circ}C$ after spin-coating the coating solutions on the polycarbonate (PC) sheets. The coating films from $TiO_2-SnO_2$ nanoparticles showed an improved pencil hardness of 3H compared to 2H of the coating films from $TiO_2$ nanoparticles. Besides, the refractive index of the coating films from $TiO_2-SnO_2$ nanoparticles enhanced from 1.543 to 1.623 at 633 nm as the Sn/Ti molar ratio increased from 0 to 0.5.

• Applied Biological Chemistry
• /
• v.24 no.2
• /
• pp.94-100
• /
• 1981

For the chemical assessment of soybean sprouts as a protein food, the changes of amino acid compositions were investigated in soybean as well as both in cotyledon and axis at various growing stages. The total amino acid content per soybean sprout was not changed until 2 days, and thereafter decreased. In cotyledon it is decreased but increased in axis. The ratio of essential amino acid to total amino acids decreased rapidly after 4 days, especially in axis. Aspartic acid increased considerably while glutamic acid decreased. The assessment of soybean sprout with chemical score, A/E and A/T, methods showed that the values were low and that there was no consistency among two methods for sprout products. The limiting amino acid was methionine. Both chemical scores by FAO reference protein and requirement pattern showed similar decreasing order of 2 day-sprout>soybean>4 day-sprout>8 day-sprout>6 day-sprout, while both essential amino acid index and requirement index showed 2 day-sprout>soybeans>4 day-sprout> 6 day-sprout>8 day-sprout.

• Applied Chemistry for Engineering
• /
• v.18 no.2
• /
• pp.188-193
• /
• 2007

Semi-solvent type cleaning agents were prepared by mixing naphthenes, natural terpene oil, surfactant and water, and measured their physical properties. And also, cleaning efficiency for flux and grease was measured by gravimetric method. By measuring the physical properties, pH for cleaning agents were 6.0~6.7, surface tension, 27.4~28.4 dyne/cm, and wetting index, 8.65~12.46 (with water), 11.99~17.43 (without water). The cleaning agent composed of naphthene, 30 wt%, natural terpene oil, 45 wt%, surfactant, 13 wt%, co-surfactant, 12 wt%, and water, 0 wt% had the largest wetting index, and shown the most effective cleaning properties for flux (98.66%) and grease (93.44%). The conductivity with $0.5{\sim}0.9{\mu}s/cm$ to the cleaning agent containing small amount of water was found to form W/O type microemulsion.