• Bulletin of the Korean Chemical Society
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• 제13권5호
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• pp.547-550
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• 1992

The oxidation of benzaldehyde, 3,4-dimethoxy benzaldehyde, p-methoxy benzaldehyde, m-$NO_2$-benzaldehyde, and m-chlorobenzaldehyde by pyridinium chlorochromate (Corey's reagent) are reported. Michaelis-Menten behaviour is observed. The rate determining step appears to be the decomposition of a complex of benzaldehyde with PCC either through a loss of $H^+$ or $H^-$ ions.

• 대한화학회지
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• 제19권5호
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• pp.289-293
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• 1975

Dodecyl pyridinium chloride(DPC) 水溶液의 粘性度 및 密度硏究로 이 溶液에는 第一 cmc 外에 第二 cmc가 存在함을 알 수 있었다. 水化된 미셀의 부피分率${\phi}_m$은 다음 式에 따라 算出하였다. ${\Pi}_{rm}=1+2.5{\phi}_m+14.1{\phi}_m^2{\cdot}{\phi}_m-C_m$ 曲線에서 ${\phi}_m$m의 增加率은 第二 cmc 近處에서 減少되고 또 密度測定으로부터 얻은 partial specific volume($\={v}$)도 第二 cmc 近處에서 급격히 減少되고 그以上의 濃度에서는 一定値를 維持함을 알았다. 이것은 미셀의 集合型의 變化 및 미셀과 結合하고 있는 반대이온의 減少로 因한 第二 cmc에서의 미셀構造變化에 依한 것이라고 생각된다.

• Bulletin of the Korean Chemical Society
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• 제34권7호
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• pp.1990-1994
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• 2013

A novel multi-cationic borane, tri-N-methylpyridinium substituted triarylborane, $[BAr^N_3]I_3$ ($[2]I_3$) ($Ar^N=4-(4-C_5H_4N-Me)-2,6-Me_2-C_6H_2$) was prepared from the corresponding neutral tris-pyridyl borane, $BAr_3$ (2a) ($Ar=4-(4-C_5H_4N)-2,6-Me_2-C_6H_2$). The crystal structure of 2a determined by X-ray diffraction study reveals the presence of tri-coordinate boron center with peripheral pyridyl moieties. The fluoride ion affinity of the cationic borane, $[2]I_3$ was investigated by UV-vis absorption titrations and was compared with that of neutral 2a. While 2a binds fluoride with the binding constant of $1.9{\times}10^2\;M^{-1}$ in $THF/H_2O$ (9:1 v/v) mixture, $[2]I_3$ shows a very high binding constant ($K=1.0{\times}10^8\;M^{-1}$) that is greater by six orders of magnitude than that of 2a in the same medium. This result indicates that the fluorophilicity of triarylborane can be drastically enhanced by multiple pyridinium substitutions.

• 대한치과의사협회지
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• 제55권2호
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• pp.180-188
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• 2017

Introduction : Inadequate oral health control is a major risk of oral diseases. Regular home-based care is essential to maintain good oral hygiene. In particular, mouthrinses can support conventional tooth brushing in reducing accumulation of oral plaque. Effect : Antimicrobial mouthrinses are used as part of daily oral care to reduce plaque and gingivitis. Mouthrinses contains fluoride could help remineralization of enamel and dentin. The most common molecules contained in mouthrinses are chlorhexidine, essential oils, cetyl pyridinium chloride, triclosan, hyaluronic acid. Currently, chlorhexidine is the most efficacious compound, with both antiplaque and antibacterial activities. Similar results are reported for essential oils and cetyl pyridinium chloride, although with a somewhat reduced efficacy. Considering the adverse effects of chlorhexidine and its time-related characteristics, this molecule may best be indicated for acute/short term use, while essential oils and cetyl pyridinium chloride may be appropriate for long-term, maintenance treatment. Conclusion and suggestion : Antimicrobial mouthrinses are safe and effective, and when used in conjunction with brushing and flossing, they are an important method of reducing plaque and gingivitis. To improve compliance, dental health care professionals should adapt oral health care recommendations to fit patients' specific needs.

• Journal of Pharmaceutical Investigation
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• 제24권4호
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• pp.273-279
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• 1994

The stability of three oximes, Hl-6 [(4-carbamoyl-2'[(hydroxyimino)-methyl]- 1,1'-oxydimethylenedi-(pyridinium chloride)], Hl-CN [(4 cyano-2'-[(hydroxyimino)-methyl] -1,1'-oxydimethylene-di-(pyridinium chloride)], and 2-PAM [pralidoxime chloride] in aqueous solutions was evaluated by HPLC assay. The rate of degradation is dependent on the pH as well as the temperature at which the solution is stored. The optimum pH for the stability of these oximes was pH 2 to 3. The degradation rate constant for 2-PAM ($k\;at\;70^{\circ}C$, $2.07{\times}10^{-4}/hr;\;E_a\;value$, 27.2 kcal/mol) was smaller than those for bis-pyridiniumoximes, Hl-6 ($k\;at\;70^{\circ}C$, $3.38{\times}10^{-3}/hr$) and Hl-CN ($k\;at\;70^{\circ}C$, $8.66{\times}10^{-3}/hr;\;Ea\;value$, 20.7 kcal/mol). In mechanistic analyses, it was found that Hl-CN was decomposed through not only the hydrolysis of nitrile group but also the cleavage of methylene ether bridge, in contrast to Hl-6 which was degraded mainly through the cleavage of methylene ether bridge.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1988년도 추계학술대회 논문집
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• pp.54-57
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• 1988

A film is fabricated by depositing several slices ultra thin films on a slide glass. The UV-absorbance outcomed on a multi-layered bulky ultra thin film with (N-docosyl pyridinium)-TCNQ (1:2) complex results tat the quantity of UV-absorbances becomes more linearly according to the number of layer becomes higher. In addition, it is found that the capacitance of this film gets smaller as the number of layer gets higher. Finally, the conductivity of this film is measured by the direction of the long axis of the TCNQ radical anion, and is resulted in a remarkably low value (about 1.66∼3.78 x 10$\^$-14/S/cm).

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.231-233
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• 1994

We have studied a properly of N-docosyl pyridinium(TCNQ) Langmuir-Blodgett film at room temperature with the $NO_2$ gas-detection characteristics. As a result, we have found that their conductivities were increased by 6 times at 5 layers(about $250{\AA}$ thickness) LB film. However, their reproducibility was not able to be measured at room temperature. Therefore, we must find their working temperature which was able to activate gas-detection characteristics. The $NO_2$ gas response experiments under 200 ppm concentration in $50^{\circ}C$ show that :here are increment of electrical conductivity by 8 times and 100 seconds of response time, and 200 seconds of recovery times at $60^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• 제5권1호
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• pp.44-49
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• 1984

The ionic association constant (K) of N-methyl pyridinium iodide (NMPI) ion in several ethanol-water mixtures were determined by the combination of UV spectroscopy and conductance measurements using the Shedlovsky function as a correction factor. The measurement of electrical conductance and UV absorption were performed in 95, 90, 80 and 60 volume percentages of ethanol in the solvent mixture at 15, 25, 35 and 45 $({\pm}0.1)^{\circ}C$. The ion size parameter $(r_A+_D-)$ and the dipole moment $({\mu}_A+_D-)$ of NMPI ion were obtained from he linear plots of ln K vs. (1/D) and (D-1)/(2D+1), respectively. These ${\mu}_A+_D-$ values were in good agreement with the values of transition moment calculated from the equation, ${\mu}_{nm}=6.5168{\times}10^{-2}{\times}({\varepsilon}_{max}{\frac{\bar{\nu}_{\frac{1}{2}}}{\bar{\nu}_{max}})^{\frac{1}{2}}$ (Debye) which we have derived. The thermodynamic parameters indicate (1) that the water dipoles have an ordered rearrangement around the dipolar NMPI ions rather than the configuration existing in bulk free waters; and (2) that the equilibrium state between NMPI ion and its component ions are controlled by entropy.

• Bulletin of the Korean Chemical Society
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• 제19권7호
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• pp.724-725
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• 1998

• Bulletin of the Korean Chemical Society
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• 제19권7호
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• pp.730-732
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• 1998