• KSBB Journal
• /
• 제22권5호
• /
• pp.362-365
• /
• 2007

Cyanobacteria have been identified as one of the most promising group producing novel biochemically active natural products. Cyanobacteria are a very old group of prokaryotic organisms that produce very diverse secondary metabolites, especially non-ribosomal peptide and polyketide structures. Large multienzyme complexes which are responsible for the non-ribosomal biosynthesis of peptides are modular for the addition of a single amino acid. An activation of amino acid substrates results in an amino adenylate occuring via an adenylation domain (A-domain). A-domains are responsible for the recognition of amino acids as substrates within NP synthesis. The A-domain contains ten conserved motifs, A1 to A10. In this study, ten conserved motifs from A1 to A10 were checked regarding their amino acid sequence of the NRPS-module of Microcystis aeruginosa PCC 7806. The part of the amino acid sequence chosen was that which contained as many conserved motives as possible, and then these amino sequence were compared between other cyanobacteria to design a new degenerate primer. A new degenerate primer (A3/A7 primer) was designed to detect any putative NP synthetase region in unkwon cyanobacteria by a reverse translation of the conserved amino acid sequence and a search for cyanobacterial DNA bank.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• 제22권11호
• /
• pp.1034-1046
• /
• 2011

In this paper, a design and fabrication of 40 W power amplifier for the X-band using load-pull measurement of GaN HEMT chip are presented. The adopted active device for power amplifier is GaN HEMT chip of TriQuint company, which is recently released. Pre-matched fixtures are designed in test jig, because the impedance range of load-pull tuner is limited at measuring frequency. Essentially required 2-port S-parameters of the fixtures for extraction optimal input and output impedances is obtained by the presented newly method. The method is verified in comparison of the extracted optimal impedances with data sheet. The impedance matching circuit for power amplifier is designed based on EM co-simulation using the optimal impedances. The fabricated power amplifier with 15${\times}$17.8 $mm^2$ shows the efficiency above 35 %, the power gain of 8.7~8.3 dB and the output power of 46.7~46.3 dBm at 9~9.5 GHz with pulsed-driving width of 10 usec and duty of 10 %.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• 제38권10호
• /
• pp.1-9
• /
• 2001

The MAC (Medium Access Control) protocol is needed for the OLT(Optical Line Termination) to allocate bandwidth to ONUs(Optical Network Units) and ONTs(Optical Network Terminations) dynamically in the ATM PON(Passive Optical Network). With the protocol, the OLT gathers ONUs' informations and provides grants efficiently to each ONU. Two important functions of the MAC protocol is the grant request procedure and the grant distribution algrithm. The latter has the greatest arithmetic portion in the TC(Transmission Convergence) module, occupies a relatively large portion of the overall chip area, has often been the limiting factor in terms of speed, and should be designed to guarantee the quality of service for various traffics. In this paper, we implement the MAC with the FPGA which can allocate grants dynamically according to the queue length information and the number of active ONUs and distribute grants uniformly to minimize the cell delay variation for each ONU. The structure of the MAC scheduler for the dynamic bandwidth assignment has a programmable look-up table. Also, it has a simple structure, the less chip area, and the lower delay time.

• Journal of Digital Convergence
• /
• 제13권4호
• /
• pp.25-38
• /
• 2015

In case of current South Korea, the rapid graying is in the progress. Because of it, the increase of elders who live alone causes variety of social, economic and national problems. Especially in the modern city, the health care, safety and maintenance of pleasant and joyful life of elders who live alone are being a big social issue. Even though practical services have been tried at the whole of government approach, the detailed alternatives are insufficient to improve the daily life support and service to approach the information. This research suggests the "ELA Service Model" which actively improves the easy access to information and corresponds to condition and circumstance of elders for providing the ICT-base Elderly Living alone care service. It is a step self-life support service based on fundamental desire of elders which resolves the problem and contributes to establish the active and balanced policy to the elderly.

• The Journal of Engineering Geology
• /
• 제10권2호
• /
• pp.52-74
• /
• 2000

The basement rock of upper stream of Keum River Valley consists of Precambrian gneiss which is resistant to weathering. That of mid and lower stream valley, however, is mainly composed of Mesozoic granites which are vulnerable to weathering. The upstream part of Geum River Basin is typified by the deeply-incised and steep meandering streams, whereas mid and lower part is characterized by wide floodplain and gently dipping river bottom toward the Yellow Sea. In particular flooding deposits, in which are imprinted a number of repetitions of erosion and sedimentation during the Holocene, are widely distributed in the lower stream of Geum River Basin. For understanding of erosions in the mid and lower stream of Geum River Basin, the rate of erosion of each small basins were estimated by using the data of field survey, erosional experiments and GIS ananlysis. It was revealed that erosion rate appeared highest in granite areas, and overall areas, in this field survey were represented by relatively high erosion rates. By implemeatation of remote sensing and imagery data, the temporal changes of river bed sediments for about last 11 years were successfully monitored. Observed as an important phenomenon is that the river bed has been risen since 1994 when an embankment (Dyke) was constructed in the estuarine river mouth. From the results derived from the detailed river bed topographical map made in this investigation, the sedimentation of the lower river basin is considered to be deposited with about 5 cm/year for the last 11 years. Based on this river bed profile analysis by HEC-6 module, it is predicted that Geum River bed of Ganggyeong area is continuously rising up in general until 2004. Although extraction of a large amount of aggregates from Gongju to Ganggyung areas, the Ganggyung lower stream shows the distinct sedimentation. Therefore, it is interpreted that the active erosions of tributary basins Geum drainage basins can affect general river bed rising changes of Geum River.

• Bulletin of the Korean Chemical Society
• /
• 제31권1호
• /
• pp.52-58
• /
• 2010

Human histamine H1 receptor (HHR1) is a G protein-coupled receptor and a primary target for antiallergic therapy. Here, the ligand-based three-dimensional pharmacophore models were built from a set of known HHR1 inverse agonists using HypoGen module of CATALYST software. All ten generated pharmacophore models consist of five essential features: hydrogen bond acceptor, ring aromatic, positive ionizable and two hydrophobic functions. Best model had a correlation coefficient of 0.854 for training set compounds and it was validated with an external test set with a high correlation value of 0.925. Using this model Maybridge database containing 60,000 compounds was screened for potential leads. A rigorous screening for drug-like compounds unveiled RH01692 and SPB00834, two novel molecules for HHR1 with good CATALYST fit and estimated activity values. The new lead molecules were docked into the active site of constructed HHR1 homology model based on recently crystallized squid rhodopsin as template. Both the hit compounds were found to have critical interactions with Glu177, Phe432 and other important amino acids. The interpretations of this study may effectively be deployed in designing of novel HHR1 inverse agonists.

• Bulletin of the Korean Chemical Society
• /
• 제30권5호
• /
• pp.1152-1156
• /
• 2009

Silent information regulator 2 (Sir2) or sirtuins are NAD(+)-dependent deacetylases, which hydrolyze the acetyllysine residues. In mammals, sirtuins are classified into seven different classes (SIRT1-7). SIRT1 was reported to be involved in age related disorders like obesity, metabolic syndrome, type II diabetes mellitus and Parkinson’s disease. Activation of SIRT1 is one of the promising approaches to treat these age related diseases. In this study, we have used HipHop module of CATALYST to identify a series of pharmacophore models to screen SIRT1 enhancing molecules. Three molecules from Sirtris Pharmaceuticals were selected as training set and 607 sirtuin activator molecules were used as test set. Five different hypotheses were developed and then validated using the training set and the test set. The results showed that the best pharmacophore model has four features, ring aromatic, positive ionization and two hydrogen-bond acceptors. The best hypothesis from our study, Hypo2, screened high number of active molecules from the test set. Thus, we suggest that this four feature pharmacophore model could be helpful to screen novel SIRT1 activator molecules. Hypo2-virtual screening against Maybridge database reveals seven molecules, which contains all the critical features. Moreover, two new scaffolds were identified from this study. These scaffolds may be a potent lead for the SIRT1 activation.

• Journal of the Korean Chemical Society
• /
• 제55권4호
• /
• pp.703-714
• /
• 2011

The purpose of this study was to investigate the effect of STS modules reflecting Ansan's geological characteristics in Chemistry I on high school students' science related attitudes and preference for STS lessons. The subjects were 10th grade students from K High School in Ansan and comprised 71 students in the experiment group and 78 students in the control group from 2 classes each. Pretest-posttest control group design was employed for the purpose of research. Four STS modules with lesson plans and teaching materials with themes of water, air, and energy, all of which are closely related to high school Chemistry I were developed and applied to the experiment group. The science related attitudes and preference for STS lessons were then examined in pre- and post-tests. The science related attitudes of the experiment group were significantly high in three out of five domains compared to the control group who was taught traditionally. The preference for STS lessons of the experiment group were highly positive in all five areas and were particularly high in the area of 'relation to society'. Such results imply that in order to make effective high school Chemistry I curriculum units related to STS, emphasized by both the 7th National Curriculum and the Revised 7th National Curriculum, it is necessary to use episodes reflecting local characteristics in which students show greater interest and active participation.

• Journal of Korean Physical Therapy Science
• /
• 제9권4호
• /
• pp.83-94
• /
• 2002

Within physical therapy education, there has been increased attention to curricula and course that emphasize problem solving, clinical reasoning, and synthesis of information across traditional discipline-specific boundaries. This article describes the development implementation, and outcomes of a problem-based learning course in Physical therapy. The course was designed to help students to integrate the various elements of a physical therapy curriculum and to enhance their abilities to respond to an ever-changing health care environment. An evaluation of the course by the first 50 students who completed it revealed both strengths and weaknesses. Students responded that the course enhanced their professional behavior, including interpersonal communication skills, team work, and follow-through with professional responsibilities. The learning package was developed by the authors and implemented to a college students during three weeks of the first semester of 2001. Most studies which conducted PBL module development were short period or temporary PBL package application and evaluation rather than a whole semester's. While, this study carried on partial integrated PBL curriculum development and application with recomposing content of the two subjects to one subject Physical therapy which includes four PBL packages. This package was developed from a simple concept to complex and partial integrated PBL curriculum application systematically variable learning methods such as discussion, practice, lecture, video. There are 2 classes, each class has 25 students, in the college. Each class has 5 small groups consisting 5 students. Two tutors proceeded discussion charging each class also, they used multiple methods and materials like tutorials, self-directed learning, lecture, and video. The package is 5 grades and 5 hours per week and the rate of discussion, lecture is 4, 1 respectively. One of the most change is the increase of interaction between students and tutors. Whenever students need information and suggestion, they can visit tutors who provide reading materials and guide for the direction of self learning. Therefore, this study describes the PBL package development process and application during one semester recomposing contents of two subjects to Physical therapy concepts. Besides, it will contribute to active application of existing each subject to tutors who intend to convert as PBL methods. The study has significant meaning to show potentiality of partially integrated PBL application, using systematic PBL package development from two subjects contents. However, when students' need of yearning is over the extent of Introduction of Physical therapy and Rehabilitation medicine, tutors should set learning extent. So, there is limitation to attain completely integrated PBL education within one subject, therefore, it is high lighted to proceed development of integrated curriculum to maximize learning effects of PBL. It is exected that partial integrated PBL package development and application will distribute to prosper excellent physiotherapist in practice.

• Microbiology and Biotechnology Letters
• /
• 제48권2호
• /
• pp.158-166
• /
• 2020

A gene coding for the xylanase was cloned from Paenibacillus woosongensis, followed by determination of its complete nucleotide sequence. This xylanase gene, designated as xyn10A, consists of 1,446 nucleotides encoding a polypeptide of 481 amino acid residues. Based on the deduced amino acid sequence, Xyn10A was identified to be a modular enzyme composed of a catalytic domain highly homologous to the glycosyl hydrolase family 10 xylanase and a putative carbohydrate-binding module (CBM) in the C-terminus. By using DEAE-sepharose and phenyl-sepharose column chromatography, Xyn10A was purified from the cellfree extract of recombinant Escherichia coli carrying a P. woosongensis xyn10A gene. The N-terminal amino acid sequence of the purified Xyn10A was identified to exactly match the sequence immediately following the signal peptide predicted by the Signal5.0 server. The purified Xyn10A was a truncated protein of 33 kDa, suggesting the deletion of CBM in the C-terminus by intracellular hydrolysis. The purified enzyme had an optimum pH and temperature of 6.0 and 55-60℃, respectively, with the kinetic parameters V_max and K_m of 298.8 U/mg and 2.47 mg/ml, respectively, for oat spelt xylan. The enzyme was more active on arabinoxylan than on oat spelt xylan and birchood xylan with low activity for p-nitrophenyl-β-xylopyranoside. Xylanase activity was significantly inhibited by 5 mM Cu²⁺, Mn²⁺, and SDS, and was noticeably enhanced by K⁺, Ni²⁺, and Ca²⁺. The enzyme could hydrolyze xylooligosaccharides larger than xylobiose. The predominant products resulting from xylooligosaccharide hydrolysis were xylobiose and xylose.