• BMB Reports
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• v.42 no.1
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• pp.47-52
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• 2009

Alanine racemase catalyzes the interconversion of L-alanine and D-alanine and plays a crucial role in spore germination and cell wall biosynthesis. In this study, alanine racemase produced by Bacillus anthracis was expressed and purified as a monomer in Escherichia coli and the importance of lysine 41 in the cofactor binding octapeptide and tyrosine 270 in catalysis was evaluated. The native enzyme exhibited an apparent $K_m$ of 3 mM for L-alanine, and a $V_{max}$ of $295\;{\mu}moles/min/mg$, with the optimum activity occurring at $37^{\circ}C$ and a pH of 8-9. The activity observed in the absence of exogenous pyridoxal 5'-phosphate suggested that the cofactor is bound to the enzyme. Additionally, the UV-visible absorption spectra indicated that the activity was pH independece, of VV-visible absorption spectra suggests that the bound PLP exists as a protonated Schiff's base. Furthermore, the loss of activity observed in the apoenzyme suggested that bound PLP is required for catalysis. Finally, the enzyme followed non-competitive and mixed inhibition kinetics for hydroxylamine and propionate with a $K_i$of $160\;{\mu}M$ and 30 mM, respectively.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.1
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• pp.24-31
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• 2011

In order to measure corrosion level of reinforcement rebar in RC structures, non-destructive test methods which are concrete surface current density method and infrared thermographic technique were employed to measure corrosion levels. Experimental test parameters were various levels of corrosion states(0, 1, 3, 5, 7% of weight loss) and concrete cover depth(30 mm, 40 mm) and two different reinforcing rebar arrangements. The larger amount of concrete surface current density, the higher corrosion level in reinforcement rebar. The laboratory conditions which are ambient temperature and humidity have negligible effect on the infrared thermographical data. After analysis of current density and temperature distribution from concrete surface, corrosion level of reinforcement rebar embedded in concrete can be measured qualitatively based on the amount of electric current and heat flux.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.4 s.27
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• pp.267-272
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• 2006

Butterfly valves have been used for shut-off and throttling-control application in many industrial fields. Recently, they are frequently used for cooling water, oil system and ballast piping system of many larger vessels. They are especially suited for flow throttling control of heat exchangers in engine room. Measurement by the PIV(Particle Image Velocimetry) was conducted to investigate the flow characteristics of butterfly valve inserted within circular pipe. Flow behaviors such as instantaneous and time-mean velocity vectors are investigated. Furthermore, to reveal systematic performance of the butterfly valve, wall pressure was measured at 6 points along the pipe by digital manometer. As the valve position moves to the closed side, flow separation increases and persists its tendency downstream until smoothly uniform flow developed. The pressure loss is found to be about zero for the disk open angles less than 45 degrees, but is substantially increased for those larger than 60 degrees.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.12
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• pp.1722-1724
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• 2003

The possibility of using cotton stems as a roughage source in animal feeding was explored. Ground cotton stems (T2 and T3) or stems treated with 0.5% urea (T4 and T5) were ensiled with pearl millet green fodder in double lined plastic bags of 3 kg capacity for 50 days. Formic acid (0.4% v/v) was sprayed on T3 and T5 silages. The treatments were compared with pearl millet silage alone (T1) which constituted the control. All the bags were placed in the silo pit of pearl millet silage. Results indicated that urea treatment of cotton stems increased and formic acid application reduced dry matter loss of the silages. Inclusion of cotton stems in the silage significantly (p<0.05) increased CF, ADF, cellulose and ADL due to its higher cell wall content. The hemicellulose was significantly lower in T3 (16.7%) and T5 (22.52%) as compared to T2 (23.45%) and T4 (24.6%) due to formic acid application. Ammoniation significantly increased NH3-N content in T4 (0.202%) and formic acid controlled NH3-N level in T5 (0.107%).The in sacco dry matter digestibility was significantly higher (p<0.05) in formic acid preserved silages T3 and T5 (47.73 and 47.93%) as compared to silages without formic acid (44.94 and 41.22 %) in T2 and T4 respectively, but lower than T1 (54.39%). It is concluded that cotton stems can be ensiled with pearl millet fodder in 1:4 ratio with or without urea treatment. Formic acid application further increases the silage quality.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7241-7244
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• 2014

Background: To determine the accuracy of preoperative urinary symptoms, urinalysis, computed tomography (CT) and cystoscopic findings for the diagnosis of urinary bladder invasion in patients with colorectal cancer. Materials and Methods: Records of patients with colorectal cancer and a suspicion of bladder invasion, who underwent tumor resection with partial or total cystectomy between 2002 and 2013 at the Faculty of Medicine Siriraj Hospital, were reviewed. Correlations between preoperative urinary symptoms, urinalysis, cystoscopic finding, CT imaging and final pathological reports were analyzed. Results: This study included 90 eligible cases (71% male). The most common site of primary colorectal cancer was the sigmoid colon (44%), followed by the rectum (33%). Final pathological reports showed definite bladder invasion in 53 cases (59%). Significant features for predicting definite tumor invasion were gross hematuria (OR 13.6, sensitivity 39%, specificity 73%), and visible tumor during cystoscopy (OR 5.33, sensitivity 50%, specificity 84%). Predictive signs in CT imaging were gross tumor invasion (OR 7.07, sensitivity 89%, specificity 46%), abnormal enhancing mass at bladder wall (OR 4.09, sensitivity 68%, specificity 66%), irregular bladder mucosa (OR 3.53, sensitivity 70%, specificity 60% ), and loss of perivesical fat plane (OR 3.17, sensitivity 81%, specificity 43%). However, urinary analysis and other urinary tract symptoms were poor predictors of bladder involvement. Conclusions: The present study demonstrated that the most relevant preoperative predictors of definite bladder invasion in patients with colorectal cancer are gross hematuria, a visible tumor during cystoscopy, and abnormal CT findings.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.393-397
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• 2001

The innovatory process, that is the direct separation and recovery of the iron and zinc metals contained in the high temperature exhaust gas generated from the electric arc furnace fer the inn scrap melting and/or the dust treatment, has been proposed. This proposed process consists of the moving coke bed filter that is directly connected to the electric furnace, and the following heavy metal condenser. The exhaust gas passes through the filter and the condenser right after exhausting from the electric furnace. The moving coke bed filter is being controlled at about 1000℃ and collects iron and slag components contained in the high temperature exhaust gas. Heavy metals such as zinc and lead pass through the filter as vapor. Based on the thermodynamic considerations, the iron oxide and the zinc oxide are reduced in the filter. The solution loss reaction rate is comparatively low at about 1000℃ in the coke bed filter by the analysis using the mathematical simulation model. The heavy metal condenser is installed in the position after the coke bed filter, and rapidly cools the gas from about 1000℃ to 450℃ by a full of the cooling medium like the solid ceramic ball in addition to the cooling from the wall. The zinc and lead vapor condense and separate f개m the gas in a liquid state. The investigation of the characteristics of the exhaust gas of the commercial electric arc furnace, the fundamental experiments of the laboratory scale and the bench scale ensured the formation of this proposed process. A small-scale pilot plant examination is carrying out at present to confirm the formation of the process. It is certain that the dust generation of the electric arc furnace is extremely decreased, and it can save the energy consumption of usual dust treatment processes by the realization of this process.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.645-649
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• 2009

Liquid desiccant cooling technology can supply cooling by using waste heat and solar heat which are hard to use effectively. For compact and efficient design of a dehumidifier, it is important to sustain sufficient heat and mass transfer surface area for water vapor diffusion from air to liquid desiccant on heat exchanger. In this study, the plate type heat exchanger is adopted which has extended surface, and hydrophilic coating and porous layer coating are adopted to enhance surface wettedness. PP(polypropylene) plate is coated by porous layer and PET(polyethylene terephthalate) non-woven fabric is coated by hydrophilic polymer. These coated surfaces have porous structure, so that falling liquid film spreads widely on the coated surface foaming thin liquid film by capillary force. The temperature of liquid desiccant increases during dehumidification process by latent heat absorption, which leads to loss of dehumidification capacity. Liquid desiccant is cooled by cooling water flowing in plate heat exchanger. On the plate side, the liquid desiccant can be cooled by internal cooling. However the liquid desiccant on extended surface should be moved and cooled at heat exchanger surface. Optimal mixing and distribution of liquid desiccant between extended surface and plate heat exchanger surface is essential design parameter. The experiment has been conducted to verify effective surface treatment and distribution characteristics by measuring wall side flow rate and visualization test. It is observed that hydrophilic and porous layer coating have excellent wettedness, and the distribution can be regulated by adopting holes on extended surface.

• The Journal of the Korean dental association
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• v.48 no.1
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• pp.45-55
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• 2010

Purpose: The aim of this study was to evaluate 1 year cumulative survival rate of implants placed on augmented sinus using Osteon$^{(R)}$, bone graft material and to assess height of the grafted material radiographically. Material and Methods: 10 maxillary sinuses were augmented in 10 patients and 25 implant fixtures were installed simultaneously or after 6 months healing period. The height of the sinus graft material was measured using panoramic images immediately after augmentation and up to 19 months subsequently. Changes in the height of the sinus graft material were calculated with respect to implant length and original sinus wall height. Results: The cumulative survival rate was 100% in all 25 implants. Additionally, normal healing process without any complication was observed in all patients. The mean crown/Implant ratio was 1.25. The mean marginal bone loss was 0.95mm and the mean resorption rate of Osteon$^{(R)}$ was 0.05mm/month. The fastest resorption site of Osteon$^{(R)}$ is the first molar area. The grafted material was well maintained in sinus and decreased slightly over 1 year. Conclusion: In conclusion, It can be suggested that Osteon$^{(R)}$ may have predictable result when it was used as a grafting material for sinus floor augmentation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2446-2452
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• 2009

A Ceramic Metal-halide lamp is achieved by adding multiple metals to a basic mercury discharge. Because the vapor pressure of most metals is very much lower than mercury itself, metal-halide salts of the desired metals, having higher vapor pressures, are used to introduce the material into the basic discharge. The metal compounds are usually polyatomic iodides, which vaporize and subsequently dissociate as they diffuse into the bulk plasma. Metals with multiple visible transitions are necessary to achieve high photometric efficiency and good color. Compounds of Sc, Dy, Ho, Tm, Ce, Pr, Yb and Nd are commonly used. The maximum visible efficacy of a Ceramic Metal Halide lamp, under the constant of a white light source, is predicted to be about 450lm/W. This is controlled principally by the chemical fill chosen for a particular lamp. Current these lamps achieve 130lm/W and these life time are the maximum 16,000[hr]. So factors of performance lower are necessary to improve lamp performance. In this paper, we analyzed factors of performance lower by accelerated deterioration test. The lamp was operated with short duration turn-on/turn-off procedure to enhance the effect due to electrode sputtering during lamp ignition. The tested lamp that was operated with a longer turn-on/off(20/20 minutes) showed blackening, changed distance between electrodes and lowered color rendering & color temperature by losses of Dy at 421.18nm, I at 511nm, T1 at 535nm and Na at 588nm compared with the new lamp.

• Journal of Korean Society of Forest Science
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• v.101 no.4
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• pp.558-566
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• 2012

This study was conducted to offer preliminary data for a natural restoration by the actual condition survey of quarries after extracting rock materials. The mountain restoration area according to a farming and fishing village organize project was restored by green landscape after quarry. However, planting tree species were died due to poor maintenance and administration after restoration works and surface soil loss and erosion occurred during a summer rainfall season because of poor slope greening. It will be needed to review restoration constructions to establish a natural friendly and flawless construction through the selection of optimum restoration works and the examination of soil and geological characteristics. In addition, it is necessary to apply cost-reducing program of restoration constructions. Quarry areas could be restored by the selection of simple and optimum construction works because the most areas were dominant in earth-sand rocks, soft-rocks, and weather-rocks. In addition, the restoration construction project should be examined thoroughly by restoration specialists during green restoration planning and review processes.