• Bulletin of the Korean Chemical Society
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• 제30권12호
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• pp.2938-2942
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• 2009

New receptors 1-3 that bind stereoselectively amino alcohols and convert chirality of amino acidsvia imine bond formation were synthesized. The receptors have uryl (1), thiouryl (2) and guanidinium (3) groups all with additional phenylcarbonyl motifs, which are effective hydrogen bonding donors and play a key role in the stereoselective recognitions. The stereoselectivities were measured from the integration of $^1HNMR$ peaks. Compound 1 and 2 showed the stereoselectivities for the imine formation with amino alcohols ($K_R/K_S$) in the range of 2${\sim}$4, and compound 3 in the range of 4${\sim}$8. Chirality conversion efficienciesof 1-3 for amino acids, i.e. D/L ratio at equilibrium, are in the range of 1.5${\sim}$5.6, showing a little higher efficiency with 3. The additional phenylcarbonyl motifs in 1-3 were revealed not to contribute to significant enhancement of the selectivities.

• Journal of Microbiology and Biotechnology
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• 제13권4호
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• pp.578-583
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• 2003

The desulfurization genes (dszABC) were cloned from Gordonia nitida. Nucleotide sequences similarity between the dszABC genes of G. nitida and those of Rhodococcus rhodochrous IGTS8 was 89%. The similarities of deduced amino acids between the two were 86% for DszA, 86% for DszB, and 90% for DszC. The G. nitida dszABC genes were expressed in several different Escherichia coli strains under an inducible trc promoter. Cultivation of these metabolically engineered E. coli strains in the presence of 0.2 mM dibenzothiophene (DBT) allowed the conversion of DBT to 2-hydroxybiphenyl (2-HBP), which is the final metabolite of the sulfur-specific desulfurization pathway. The maximum conversion of DBT to 2-HBP was 16% in 60 h. Recombinant E. coli was applied for the deep desulfurization of diesel oil supplemented into the medium at 5% (v/v). Sulfur content in diesel oil was decreased from 250 mg sulfur/1 to 212.5 mg sulfur/1, resulting in the removal of 15% of sulfur in diesel oil in 60 h.

• Journal of Ecology and Environment
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• 제41권3호
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• pp.78-84
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• 2017

Recently, great demands are rising around the globe for monitoring and studying of long-term ecological changes. To go with the stream, many researchers in South Korea have attempted to share and integrate ecological data for practical use. Although some achievements were made in the meantime, we still have to overcome a big obstacle that existing ecological data in South Korea are mostly spread all over the country in various formats of computer files. In this study, we aim to handle the situation by developing a semi-automatic data conversion tool for Korean ecological data standardization, based on some predefined protocols for ecological data collection and management. The current implementation of this tool works on only five species (libythea celtis, spittle bugs, mosquitoes, pinus, and quercus mongolica), helping data managers to quickly and efficiently obtain a standardized format of ecological data from raw collection data. With this tool, the procedure of data conversion is divided into four steps: data file and protocol selection step, species selection step, attribute mapping step, and data standardization step. To find the usability of this tool, we utilized it to conduct the standardization of raw five species data collected from six different observatory sites of Korean National Parks. As a result, we could obtain a common form of standardized data in a relatively short time. With the help of this tool, various ecological data could be easily integrated into the nationwide common platform, providing broad applicability towards solving many issues in ecological and environmental system.

• Journal of Plant Biotechnology
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• 제29권4호
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• pp.253-257
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• 2002

To establish the optimum condition for plant regeneration from somatic embryos of Acanthopanax sessiliflorus Rupr. et Maxim, a medicinal plant, somatic embryos were induced from zygotic embryo-derived embryogenic callus in hormoen-free MS medium. To induce plantlet conversion, cotyledonary somatic embryos were cultured on MS solid medium with GA$_3$at various concentrations (0~10 mg/L) for three weeks. Plantlets were transferred to 1/3 MS solid medium with 0.5% charcoal for 7 weeks. Stem length was increased proportionally to the concentration and treatment period of GA$_3$. Also, the highest leaf width (8.9 mm) and leaf number (2.84) of plantlet were obtained when plantlets were converted on 5,10 mg/L GA$_3$pretreatments, respectively. The highest plant conversion frequency (66.7%) was obtained when the somatic embryos were cultured on medium containing 5 mg/L GA$_3$ for 3 weeks and then were transferred to 1/3 MS medium with 0.5% charcoal. The highest survival rate of soil transfer was 90% when plantlets were regenerated on medium with 5 mg/L GA$_3$ for 3 weeks and then transferred to plastic pots containing vermiculite and sand mixture for 4 weeks.

• 공업화학
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• 제21권2호
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• pp.154-161
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• 2010

본 연구는 갈조류인 다시마를 이용한 생물학적 바이오 에탄올 생산 과정에서 산 및 염 농도가 미치는 영향과 다시마에 포함된 다당류 성분 중 에탄올로 전환 가능한 유용 기질에 대해 연구하였다. 다시마를 이용한 에탄올 발효에는 Saccharomyces cerevisiae KCCM1129를 이용하였으며, 고압멸균기를 이용한 열 처리 다시마에서 최대 2.09 g/L의 에탄올 생산을 확인할 수 있었다. 산 전처리 과정을 통해 1.0 N HCl에서 최대 3.95 g/L의 환원당이 생성되었으나 에탄올 생산은 오히려 산 처리를 하지 않은 배지에서 더욱 높게 나타났다. 산 처리시 생성되는 염의 영향을 확인 결과 염 농도의 증가에 따라 에탄올 발효가 저해되는 것을 확인할 수 있다. 갈조류 주요 구성 다당류를 이용한 발효에서 mannitol만이 열처리에서 최대 3.09 g/L까지 에탄올로 전환 가능한 것으로 확인되었으며, laminaran의 경우 0.1 N HCl을 처리하였을 때 0.15 g/L의 소량의 에탄올 생산이 확인되었으며, 산 처리에서 세포 성장이 다른 기질에 비해 크게 증가하는 것으로 나타났다.

• Carbon letters
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• 제17권1호
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• pp.1-10
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• 2016

Lignocellulosic biomass conversion to biofuels such as ethanol and other value-added bio-products including activated carbons has attracted much attention. The development of an efficient, cost-effective, and eco-friendly pretreatment process is a major challenge in lignocellulosic biomass to biofuel conversion. Although several modern pretreatment technologies have been introduced, few promising technologies have been reported. Microwave irradiation or microwave-assisted methods (physical and chemical) for pretreatment (disintegration) of biomass have been gaining popularity over the last few years owing to their high heating efficiency, lower energy requirements, and easy operation. Acid and alkali pretreatments assisted by microwave heating meanwhile have been widely used for different types of lignocellulosic biomass conversion. Additional advantages of microwave-based pretreatments include faster treatment time, selective processing, instantaneous control, and acceleration of the reaction rate. The present review provides insights into the current research and advantages of using microwave-assisted pretreatment technologies for the conversion of lignocellulosic biomass to fermentable sugars in the process of cellulosic ethanol production.

• Journal of Ecology and Environment
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• 제41권5호
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• pp.142-144
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• 2017

In recent decades, as it becomes increasingly important to monitor and research long-term ecological changes, worldwide attempts are being conducted to integrate and manage ecological data in a unified framework. Especially domestic ecological data in South Korea should be first standardized based on predefined common protocols for data integration, since they are often scattered over many different systems in various forms. Additionally, foreign ecological data should be converted into a proper unified format to be used along with domestic data for association studies. In this study, our interest is to integrate ECN data with Korean domestic ecological data under our unified framework. For this purpose, we employed our semi-automatic data conversion tool to standardize foreign data and utilized ground beetle (Carabidae) datasets collected from 12 different observatory sites of ECN. We believe that our attempt to convert domestic and foreign ecological data into a standardized format in a systematic way will be quite useful for data integration and association analysis in many ecological and environmental studies.

• Journal of Acupuncture Research
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• 제26권1호
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• pp.197-206
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• 2009

Objectives : This is a clinical report about the Conversion Disorder, Wei symptom patient. Methods : The patient was treated by acupuncture, herb medication, moxibustion, physical therapy and bio feedback. The improvement of the patient was judged by lower limb elevation test and gait condition test. Results : During the 1st duration, lower limb elevation angle of the patient had improved. And the patient's gait condition had improved. But he received stress so that same symptom appeared again. Then, after the second treatment, He could walk alone again. Conclusions : Oriental medicine treatment including Acupuncture, Herb medication was very effctive to improve the Conversion disorder patient's symptoms. It is necessary to have more observation and many cases of patients with Conversion disorder.

• Bulletin of the Korean Chemical Society
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• 제30권2호
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• pp.409-414
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• 2009

Novel binol aldehydes derivatized at 2' hydroxy position with both uryl and acetamide groups (2), and diuryl groups (3) have been synthesized. Both were designed for streospecific binding and chirality conversion of general dipeptides with support of multiple hydrogen bonding donor sites in the receptors. The receptors, 2 and 3, converted the chirality of N-terminal amino acids of peptides such as Ala-Gly, Met-Gly, Leu-Gly and His-Gly with stereoselectivity on D-form over L-form. The stereoselectivity ratios were in the range of 5-11, somewhat higher than those of the binol receptor with mono uryl group (1). The DFT calculation at the B3LYP/6-31G$^*$//MPWB1K/6-31G$^*$ level revealed that 3-D-Ala-Gly was 2.2 kcal/mol more stable than 3-L-Ala-Gly. The considerable steric hindrance between the methyl group of the alanine and the imine CH moiety of the receptor seems to be the main contributing factor for the thermodynamic preference.

• Geomechanics and Engineering
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• 제31권3호
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• pp.281-289
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• 2022

Bio-CaCO₃ is a blowout environment-friendly materials for soil improvement and sealing of rock fissures. To evaluate the chemical characteristics, shape, size and productivity of soybean urease induced CaCO₃ precipitates (SUICP), experimental studies were conducted via EDS, XRD, FT-IR, TGA, BET, and SEM. Also, the conversion rate of SUICP reaction at different time were determined and analyzed. The Bio-CaCO₃ product obtained by SUICP is comprehensively judged as calcite based on the results of EDS, XRD and FT-IR. The SUICP calcite precipitates are detected as spherical or ellipsoidal particles 3-6 ㎛ in diameter with nanoscale pores on their surface, and this morphology is novel. The median secondary particle size d₅₀ is 39-88 ㎛, indicating the agglomeration of the primary calcite particles. The Bio-calcite decomposes at 650-780℃, representing a medium thermal stability. The conversion rate of SUICP reaction can reach 80% in 24h, which is much more efficient than microbially induced CaCO₃ precipitation. These results reveal the knowledges of SUICP, and further direct its engineering applications. Moreover, we show an economic channel to obtain porous spherical calcite.