• Restorative Dentistry and Endodontics
• /
• v.20 no.1
• /
• pp.164-172
• /
• 1995

The purpose of this electrochemical study was to determine and compare the sealing effect of three commonly used calcium hydroxide-based sealers (Sealapex, Apexit, and CRCS) with that of Roth 801 which is a ZOE-based sealer. 64 single rooted teeth were used in this experiment. After removing the crown, the teeth were devided into 4 groups of 15 in each and obturated with gutta-percha and experimental sealers. 4 teeth were as controls(2 positive and 2 negative). The results were as follows : 1. During the observation period, all sealers showed varying degree of microleakage. 2. The mean leakage currents according to the electrochemical study of each group showed $0.418{\pm}0.006mV$ for Roth 801, $2.03{\pm}0.035mV$ for Sealapex, $3.33{\pm}0.069mV$ for Apxit and $6.48{\pm}0.097mV$ for CRCS group. The positive control group showed 600mV. 3. There were statistically significant difference in mean leakage among experimental groups. ZOE-typed Roth 801 sealer was the lowest, and Sealapex, Apexit, CRCS group in that order showed increased leakage(P<0.05). 4. Roth 801, Sealapex and Apexit group showed increasing leakage with time, but CRCS group showed stable or decreasing leakage tendency.

• Applied Chemistry for Engineering
• /
• v.31 no.5
• /
• pp.495-501
• /
• 2020

In this study, zirconium fumarate of metal-organic framework (MOF-801) was solvothermally synthesized at 130 ℃ and characterized through powder X-ray diffraction (PXRD) analyses and porosity measurements from N₂ sorption isotherms at 77 K. The ability of MOF-801 to act as an adsorbent for the phosphate removal from aqueous solutions at 25 ℃ was investigated. The phosphate removal efficiency (PRE) obtained by 0.05 g/L adsorbent dose at an initial phosphate concentration of 60 ppm after 3 h was 72.47%, whereas at 5 and 20 ppm, the PRE was determined to be 100% and 89.88%, respectively, after 30 min for the same adsorbent dose. Brunauer-Emmett-Teller (BET) surface area and pore volume of the bare MOF-801 sample were 478.25 ㎡/g and 0.52 ㎤/g, respectively, whereas after phosphate adsorption (at an initial concentration of 60 ppm, 3 h), the BET surface area and pore volume were reduced to 331.66 ㎡/g and 0.39 ㎤/g, respectively. The experimental data of kinetic (measured at initial concentrations of 5, 20 and 60 ppm) and isotherm measurements followed the pseudo-second-order kinetic equation and the Freundlich isotherm model, respectively. This study demonstrates that MOF-801 is a promising material for the removal of phosphate from aqueous solutions.

• Biomolecules & Therapeutics
• /
• v.4 no.2
• /
• pp.196-201
• /
• 1996

The N-methyl-D-aspartate (NMDA) receptor-ion channel complex is activated by the simultaneous presence of L-glutamate and glycine, allowing the binding of MK-801 to the phencyclidine (PCP) site of the receptor. The $[^3H]$MK-801 binding assay system was established for determination of pharmacological functions of test compounds acting at the glycine site of the receptor. The binding in the presence of 0.1 $\mu$M L-glutamate was increased by an agonist (glycine) in a dose-dependent fashion, while decreased by either partial agonist (R-(+)-HA-966) or antagonist (5,7-dichlorokynurenic acid: 5,7-DCKA). To distinguish partial agonism from antagonism, various concentrations of 7-chlorokynurenic acid (7-CKA) were added in the assay to eliminate the interference of the endogenous glycine present in the membrane preparations. The bindings in the presence of L-glutamate (0.1$\muM$) and 7-CKA (1, 5, or 10$\muM$) were increased by R-(+)-HA-966. Being a weak partial agonist, the extent of potentiation was much less than that by the agonist. These binding profiles were clearly distinguishable from those by the antagonist, 5,7-DCKA, which exhibited no intrinsic activity. The binding assays established in the present study are a useful system to classify ligands acting at the glycine site of the NMDA receptor by their pharmacological functions.

• Journal of the Korean Institute of Navigation
• /
• v.19 no.3
• /
• pp.29-34
• /
• 1995

IEC and CISPR have continuously endeavored the measurement method of Immunity Test as international unification, but not established yet. The main reason is that the measurement method and the normalization of threshold to obtain the complicated parameters for Immunity Test are difficult. Thus, the Immunity Test Setups are used differently according to the measured electromagnetic environments. This study developed an Immunity Test System and Algorithm for measurement software suitable for IEC801-3 Regulatons using ready-made amplifier, signal generator, and developes interconnecting interface board interacting with other appratus i.e., RF Switch, Power Meter, Field Sensor and Pre-amp. We are to develope an automated software using Top/Down and OOP(Object Oriented Programming) method.

• International Journal of Oral Biology
• /
• v.34 no.2
• /
• pp.97-103
• /
• 2009

L-trans-pyrrolidine-2,4-dicarboxylate (PDC) is a potent inhibitor of glutamate transporters. In our current study, we investigated whether the neuronal death induced by PDC involves mechanisms other than excitotoxicity in mixed mouse cortical cultures. Cortical cultures at 13-14 days in vitro were used and cell death was assessed by measuring the lactate dehydrogenase efflux into bathing media. Glutamate and PDC both induced neuronal death in a concentration-dependent manner but the neurotoxic effects of glutamate were found to be more potent than those of PDC. Treatment with 10, 100 and 200 ${\mu}$M PDC equally potentiated 50 ${\mu}$M glutamate-induced neuronal death. The neuronal death induced by 75 ${\mu}$M glutamate was almost abolished by treatment with the NMDA antagonists, MK-801 and AP-5, but was unaffected by NBQX (an AMPA antagonist), trolox (antioxidant), BDNF or ZVAD-FMK (a pan-caspase inhibitor). However, the neuronal death induced by 200 ${\mu}$M PDC was partially but significantly attenuated by single treatments with MK-801, AP-5, trolox, BDNF or ZVAD-FMK but not NBQX. Combined treatments with MK-801 plus trolox, MK-801 plus ZVAD-FMK or MK-801 plus BDNF almost abolished neuronal death, whereas combined treatments with trolox plus ZVADFMK, trolox plus BDNF or ZVAD-FMK plus BDNF did not enhance the inhibitory action of any single treatment with these drugs. These results demonstrate that the neuronal death induced by PDC involves not only in the excitotoxicity induced by the accumulation of glutamate but also the oxidative stress induced by free radical generation. This suggests that apoptotic neuronal death plays a role in PDCinduced oxidative neuronal injury.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.2 no.1
• /
• pp.40-45
• /
• 1999

Purpose: The aim of this study is to investigate the seroepidemiology of hepatitis A and hepatitis B in Korean children. Methods: 801 children aged 6 to 12 years were enrolled. IgG antibody to hepatitis A virus (anti-HAV), hepatitis B surface antigen (HBsAg), antibody to HBsAg (anti-HBs), and IgG antibody to HBc (anti-HBc) were measured by radioimmunoassay. Results: Of the 801 children, the seroprevalence of anti-HAV was 0%. Three (0.4%) were seropositive for HBsAg. The seroprevalence of anti-HBs was 61.8%. Two (0.4%) of 495 anti-HBs positive subjects were positvie for anti-HBc. Of the 801 children, 658 (82.1%) had received hepatitis B vaccination. Conclusions: Since natural anti-HAV is not acquired in the childhood, the outbreak of hepatitis A is possible in adolescents and young adults. The decrease in seroprevalence of HBsAg and the increase in seroprevalence of anti-HBs might result from hepatitis B vaccination program in childhood.

• Journal of the Korean Mathematical Society
• /
• v.39 no.5
• /
• pp.801-819
• /
• 2002

In this note, we establish a translation theorem in an analogue of Wiener space (C[0,t],$\omega$$\phi$) and find formulas for the conditional $\omega$$\phi$-integral given by the condition X(x) ＝ (x(to), x(t$_1$),…, x(t$_{n}$)) which is the generalization of Chang and Chang's results in 1984. Moreover, we prove a translation theorem for the conditional $\omega$$\phi$-integral.l.

• Bulletin of the Korean Chemical Society
• /
• v.20 no.7
• /
• pp.801-804
• /
• 1999

Thermal and photoinduced silylallylation reactions of organic halides with 3-stannyl-2-(silylmethyl)propene are explored. Silylallylations occur in moderate to high yields, producing various functionalized allylsilane products in which halide carbon is bonded to the terminal alkenic carbon of allylsilane with the removal of tributyltin group. The reactions, which tolerate functional groups such as carbonyl, ester, nitrile, acetal, and ketal, hold synthetic potential for the construction of functionalized allylsilanes.

• Journal of applied mathematics & informatics
• /
• v.41 no.4
• /
• pp.801-810
• /
• 2023

The aim of this paper, investigated of weighted space which contained the unbounded functions which is to be approximated by linear operators in terms some Well-known approximation tools such as the modulus of smoothness and K-functional. The characteristics of the identical theorem between modulus of smoothness and K-functional are consider. In addition to the establish the direct, converse and identical theorem by using some linear operators in terms modulus Ditzian-Totik.

• Journal of applied mathematics & informatics
• /
• v.42 no.4
• /
• pp.801-818
• /
• 2024

The purpose of this paper is to introduce the concept of (∈, ∈ ∨q)-fuzzy congruence relation over ring and discuss some properties of the (∈, ∈ ∨q)-fuzzy congruence relation. We also establish a brief relation between (∈, ∈ ∨q)-fuzzy ideal and (∈, ∈ ∨q)-fuzzy congruence relation. The image and preimage of (∈, ∈ ∨q)-fuzzy congruence are also studied under the so called semibalanced map.