• The Journal of Advanced Prosthodontics
• /
• v.3 no.4
• /
• pp.216-220
• /
• 2011

PURPOSE. Heat of composite polymerization (HP) indicates setting efficacy and temperature increase of composite in clinical procedures. The purpose of this in vitro experimental study was to evaluate the effects of 5 temperatures on HP of two new composites. MATERIALS AND METHODS. From each material (Core Max II [CM] and King Dental [KD]), 5 groups of 5 specimens each were prepared and their total HPs (J/gr) were measured and recorded, at one of the constant temperatures $0^{\circ}C$, $15^{\circ}C$, $23^{\circ}C$, $37^{\circ}C$ and $60^{\circ}C$ ($2{\times}5{\times}5$ specimens) using a differential scanning calorimetry (DSC) analyzer. The data were analyzed using a two-way ANOVA, a Tukey's test, an independent-samples ttest, and a linear regression analysis (${\alpha}=0.05$). RESULTS. No polymerization reactions occurred at $0^{\circ}C$; then this temperature was excluded from statistical analyses. The mean HP of the remaining 20 KD specimens was $20.5{\pm}14.9$ J/gr, while it was $40.7{\pm}12.9$ J/gr for CM. The independent-samples t-test showed that there were significant differences between the HP of the two materials at the temperatures $15^{\circ}C$ (P=.0001), $23^{\circ}C$ (P=.0163), $37^{\circ}C$ (P=.0039), and $60^{\circ}C$ (P=.0106). Linear regression analysis showed statistically significant correlations between environment temperatures and HP of CM ($R^2=0.777$). CONCLUSION. Using CM is advantageous over conventional composite because of its better polymerization capacity. However due to its high HP, further studies should assess its temperature increase in vivo. Preheating KD is recommended. Refrigerating composites can negatively affect their polymerization potential.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2001.11a
• /
• pp.335-335
• /
• 2001

Direct-normal, total horizontal and diffuse horizontal irradiance data obtained from a multi-filter rotating shadowband radiometer over seven different wavelength bands (416nm, 151nm, 616nm, 675nm, 870nm and 940nm and the entire spectrum) has been analyzed at Kwangju, South Korea from June 1998 December 2000. The maximum hourly global radiation flux ranged from 0.44 MJ/$m^2$ to 2.68 MJ/$m^2$ at around 11:00-12:00 Hr local time while the maximum hourly diffuse radiation flux ranged from about 0.96 MJ/$m^2$ to 1.37 MJ/$m^2$. The maximum hourly direct irradiance ranged from 1.42 MJ/$m^2$ to 2.92 MJ/$m^2$ from June1998-2000. During the period under consideration, the average monthly global radiation recorded were 13.09 MJ/$m^2$/day, 10.58MJ/$m^2$/day and 9.78MJ/$m^2$/day for years 1998, 1999 and 2000 respectively, while the diffuse irradiance were 6.54 MJ/$m^2$/day, 5.33 MJ/$m^2$/day and 5.14 MJ/$m^2$/day for f998, 1999 and 2000 respectively. The direct irradiance values at the site were 11.63 MJ/$m^2$/day, 8.24MJ/$m^2$/day and 7.75 MJ/$m^2$/day for 1998, f999 and 2000 respectively. It was observed that each of the years has its own unique meteorological parameters that affect the quality and quantity of radiation received for each month. The annual average daily fractions of the diffuse to the global radiation (KD) were 0.51, 0.61 and 0.59 for years 1998, 1999 and 2000 respectively. Analysis indicated that the average daily KD ranged from 0.13 to a maximum value of 0.99 in May for irradiance measured at the broadband channel while the maximum and minimum KD value of 0.91 and 0.23 was recorded at wavelength band 870nm and 940nm in January and September respectively. The lowest average daily clearness index (Kt) value recorded was 0.03 in May (Spring) and the annual average daily clearness indexes are 0.45, 0.34 and 0.35 for years 1998, f999 and 2000 respectively. The frequency of clear days annually at Kwangju is 67.95%, 29.57% and 40.72% for years 1998, 1999 and 2000 respectively.

• The Transactions of the Korea Information Processing Society
• /
• v.2 no.6
• /
• pp.903-917
• /
• 1995

In most database systems images have been indexed indirectly using related texts such as captions, annotations and image attributes. But there has been an increasing requirement for the image database system supporting the storage and retrieval of images directly by content using the information contained in the images. There has been a few indexing methods based on contents. Among them, Pertains proposed an image indexing method considering spatial relationships and properties of objects forming the images. This is the expansion of the other studies based on '2-D string. But this method needs too much storage space and lacks flexibility. In this paper, we propose a more flexible index structure based on kd-tree using paging techniques. We show an example of extracting keys using normalization from the from the raw image. Simulation results show that our method improves in flexibility and needs much less storage space.

• Journal of Plant Biology
• /
• v.34 no.2
• /
• pp.121-127
• /
• 1991

Total soluble proteins from three developmental stages of induced root nodules of Canavalia lineata were compared with those of non-nodulated roots by SDS-PAGE and two dimensional (2-D) gel electrophoresis. Thirteen nodule-specific protein (nodulin) bands were identified by the former and 30 nodule specific protein spots were detected by the latter method respectively. Some of the nodulins were detected differentially depending on the nodule's developmental stages. For example, only three leghemoglobin (Lb)-like protein spots appeared at stage I (d<2 mm), but two additional Lb-like protein spots appeared at stage II (d <4-5 mm). pI value and molecular weight of nomomers of Lb-like protein were narrower and greater than those of soybean, ranging from 4.4 to 5.0 and 15.7 kd respectively. Northern blot hybridization of total RNAs from roots and root nodules using soybean Lb cDNA as a probe made it clear that Lb gene was expressed tissue-specifically only in the root nodules.odules.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1994.04a
• /
• pp.191-191
• /
• 1994

본 연구는 D-galactosamine을 이용한 중기발암성 모델에서 세포성면역중의 하나인 natural killer (NK) 세포활성과 c-myc 종양단백의 발현을 알아보기 위하여 실시하였다. 수컷 6주령의 SPF SD랫드 50마리를 3개군으로 각 군당 20마리씩 나누어 배치하였다. 실험 0일에 제 1,2 군에서 DEN을 복강내로 체중 kg당 200mg 1회 투여하여 발암유발을 하였으며 대조군인 제 3군에는 saline을 투여하였다. 제 2주에 제 1군에는 강력한 발암촉진물질인 2-acetylaminofluorene (AAF)을 사료에 0.01% 투여하였으며, 제 2군은 미약한 발암촉진물질인 phenobarbital (PB)을 0.05%로 음수에 6주간 투여하였다 제 8, 15, 36주에 경시적으로 부검하였다. 제 8주에 부검시 GST-P$^{+}$ 병변이 잘 유도되어 전암병변의 유도가 잘 되었음을 확인하였다. 제 15주에 부검시 AAF를 투여한 군에서 glutathione S-transferase placental form (GST-p)에 대한 면역조직화학적 염색에서 AAF와 PB를 투여한 제 1군 및 제 2군의 간장에서는 주위조직과 한계가 명료한 GST-P$^{+}$ 증식성 결절과 병소를 관찰할 수 있었으나 기초 사료만을 투여한 제 3군은 어떠한 GST-P$^{+}$ 증식성 결절 및 병소를 관찰할 수 없었다. 랫드에서 natural killer세포는 사람이나 마우스에서 주로 자연살생능 (natural killing activity)을 보이는 LGL(lure granular lymphocyte)의 형태를 띄고 있었으며 LGL 이라고 부르는 것처럼 특징적으로 세포질 대 핵의 비율이 높고 azurophilic 과립을 세포질내에 함유하고 있으며 일반적으로 신장 형태의 핵을 가지고 있었다. 또한 세포의 크기는 small lymphocyte와 대식세포 (macrophage)의 중간 크기였다. 15주와 시험종료시 정상대조군인 제 3군의 랫드로 부터 분리한 NK 세포활성도 (% cytotoxicity)에 비하여 발암물질 투여군의 NK 활성도는 PB 투여군들의 NK활성도 보다 약간 낮았다. 랫드에서 c-myc 종양단백은 65KD 와 671KD 에서 band가 형성된 것이 관찰되었다. 시험 개시후 15주에 부검한 랫드의 간에서 c-myc 종양단백의 발현은 모든 처리군들이 대조군에 비하여 높게 발현되는. 것이 관찰되었으나 시험개시후 26주에 부검한 랫드의 간에서 c-myc 종양단백의 발현은 대조군에 비하여 차이가 거의 없었다. 따라서 랫드에서 화학적으로 유도한 간암발생 과정에서 NK 세포활성이 현저하게 억제되는 것으로 생각되며, c-myc 종양단백의 발현은 시험개시후 15주에 그 발현이 확실한 것으로 사료되어 진다.

• Applied Biological Chemistry
• /
• v.36 no.2
• /
• pp.86-92
• /
• 1993

Myrosinase from radish was purified by DEAE Bio-Gel, Con-A, and Superose-6 column. The purified myrosinase(II) possessed 2 subunits, and their molecular as determined by SDS-polyacrylamide gel electrophoresis were 53 and 39 KD, respectively. The specific activity of purified enzyme was 37,500 units/mg. The enzyme was purified approximately 44-fold compared to the crude enzyme. Optimum pH of the myrosinase was $6.5{\sim}7.0$ in phosphate and Tris-HCl buffer solutions. Optimum temperature of the enzyme was $37{\sim}38^{\circ}C$. The enzyme was stable at pH 7.0, and less than $30^{\circ}C$. Cu or Hg ion significantly inhibited the enzyme activity, but ascorbic acid enhanced, resulting in a maximum activity by 1 mM ascorbic acid. Among the ascorbic acid analogues, dehydroascorbic acid did not affect, whereas others showed a little effect, but less than ascorbic acid itself. Individual 2-mercaptoethanol and dithiothreitol (reducing agents) did not enhance the enzyme activity. but 2-mercaptoethanol effect was enhanced when mixed with ascorbic acid.

• Microbiology and Biotechnology Letters
• /
• v.22 no.5
• /
• pp.507-514
• /
• 1994

Acetyl xylan esterase was produced by E. coli HB101 harboring a recombinant plasmid pKMG6 which contained the estI gene of Bacillus stearothermophilus. The maximum production was observed when the E. coli strain was grown at 37$\circC for 12 hours in the medium containing 0.5% acetyl xylan, 1.0% tryptons, 1.0% sodium chloride, and 0.5% yeast extract. The esterase produced was purified to homogeneity using a combination of ammonium sulfate fractionation, DEAE Sepharose CL-6B ion exchange chromatography and Sephacryl S-200 gel filtration. The native enzyme had an apparent molecular mass of 60 kd and was composed of two identical subunits of 29 kd. The N-terminal amino acid sequence of the polypeptide was Ala-X-Leu-Gln- Ile-Gln-Phe-X-X-Gln. The acetyl esterase displayed a pH optimum of 6.5 and a temperature opti- mum of 45$\circC. The heavy metal ions such as Ag$^{++}$, Hg$^{++}$ and Cu$^{++}$ inhibited nearly completely the activity of the esterase, and no specific metal ion was found to be required for the enzyme activity. The enzyme readily cleaved MAS, $\beta$-D-glucose pentaacetate, $\alpha$-naphthyl acetate, $\rho$-nitrophenyl acetate as well as acetyl xylan, but had no activity on $\rho$-nitrophenyl propionate, $\beta$-nitrophenyl butyrate or $\beta$-nitrophenyl valerate. The Km and Vmax values for MAS were 2.87 mM and 11.55 $\mu$mole/min, respectively. Synergistic behavior was demonstrated with a combination of xylanase and esterase from B. stearothermophilus in hydrolyzing acetyl xylan.

• Korean Journal of Food Science and Technology
• /
• v.27 no.5
• /
• pp.762-767
• /
• 1995

The ${\alpha}-Amylase$ inhibitor from black bean(Phaseolus vulgaris) was purified to homogeneity using 70% saturated ammonium sulfate, DEAF-cellulose, Concanavalin-A sepharose chromatography and gel filtration with Superose 6. The purified α-amylase inhibitor showed a single band of 25 KD in molecular weight on the SDS-PAGE. The specific activity of the inhibitor was 544.0 units/mg and the purity was enhanced about 18-fold. The amino acids of ${\alpha}-Amylase$ inhibitor from black bean was mainly glutamic acid, aspartic acid and lysine. The inhibitor was glycoproteins and its carbohydrate contents was 3.2%.

• Journal of Distribution Research
• /
• v.13 no.3
• /
• pp.127-154
• /
• 2008

For the large scale retailers such as chain discount stores and specialty stores, having measurement tool to maintain service quality can be very crucial to sustain high and same level of service qualities around multiple stores. This study aims to develop service quality scales of large-scale stores using Korean discount store cases. We have studied the previous service quality measures including RSQS(Retail Service Quality Scale) and have modified and developed our own scale model called KD-SQS(Korea Discount Service Quality Scale). The following six components have been revealed as the basic dimensions of service quality of Korean discount stores: basic benefits, promotion, personal interactions, physical aspects, policy and additional convenience. Our scales have been verified through various validity and reliability tests.

• Imaging Science in Dentistry
• /
• v.42 no.3
• /
• pp.155-161
• /
• 2012

Purpose: This study was performed to investigate the prevalence, morphology, and calcification pattern of the elongated styloid process in the Mathura population and its relation to gender, age, and mandibular movements. Materials and Methods: The study analyzed digital panoramic radiographs of 2,706 adults. The elongated styloid process was classified with the radiographic appearance based on the morphology and calcification pattern. The limits of mandibular protrusion were evaluated for each subject. The data were analyzed by using a Student's t-test and chi-squared test with significance set at p=0.05. Results: Bilateral elongation having an "elongated" type styloid process with a "partially mineralized" pattern was the most frequent type of styloid process. No correlation was found between styloid process type and calcification pattern on the one hand and gender on the other, although elongated styloid was more prevalent in older and male populations (p<0.05). Further styloid process elongation showed no effect on mandibular protrusive movement (p>0.05). Conclusion: Dentists should recognize the existence of morphological variation in elongated styloid process or Eagle syndrome apparent on panoramic radiographs. We found higher prevalence of elongated styloid process in the population of the Mathura region when compared with other Indian populations. The calcification of the styloid process was more common in the older age group with no correlation to gender, mandibular movement and site. "Type I" with a "partially calcified" styloid process was observed more frequently in the population studied.