• Journal of the Korean Chemical Society
• /
• v.35 no.6
• /
• pp.673-679
• /
• 1991

The electrochemical reduction of N-tert-butylbenzothiazole-2-sulfenamide (TBBS; vulcanization accelerator) was investigated by direct current, differential pulse polarography, cyclic voltammetry and controlled potential coulometry. The electrode reduction of TBBS proceeded E-C-E-C reaction mechanism by four electrons transfer at irreversible one wave (-2.31 volts vs. Ag/0.1M AgN$O_3$ in AN). As the results of controlled potential electrolysis, mercaptobenzothiazole (MBT), benzothiazole disulfide (MBT dimer) and extricated sulfur were products which followed by cleavage of the sulfenamide (-S-N=) bond. Upon the basis of products analysis and polarogram interpretation with pH variable, electrochemical reaction mechanism was suggested.

• KSBB Journal
• /
• v.18 no.4
• /
• pp.261-265
• /
• 2003

Ibuprofen was analyzed by chiral high performance liquid chromatography. Retention behaviours of the standard mixtures of ibuprofen were investigated to obtain their acceptable resolution. A chromatographic column (3.9 ${\times}$ 300 mm) was packed by Kromasil CHI-TBB packings (10 $\mu\textrm{m}$) and n-hexane was used as a mobile phase with 0.1％ acetic acid and tert-butyl methyl ether. Isocratic elution of ibuprofen at 1.0 $m\ell$/min was performed by changing the mobile phase compositions. The experimental variables affecting the resolution were the compositions of mobile phase and chemical buffer (n-hexane and tert-butyl methyl ether). The resolution between the enantiomers were correlated into the several types of empirical equations including linear form, and their agreements between experimental data and calculated values were examined by the regression coefficient.

• Tuberculosis and Respiratory Diseases
• /
• v.67 no.6
• /
• pp.545-550
• /
• 2009

Background: Endobronchial ultrasonogram (EBUS) has increased the diagnostic yield of a bronchoscopic biopsy of peripheral pulmonary lesions (PPL). This study evaluated the diagnostic yield of EBUS-guided transbronchial biopsy (TBB) and the visibility of EBUS PPL. Methods: Between August 2007 and November 2008, 50 patients (32 men and 18 women, median age, 61.1${\pm}$10 yrs; range, 16 to 80 yrs) whose PPL lesions could not be detected with flexible bronchoscopy were enrolled in this study. Among the 50 patients, 40 cases were malignant lesions (adenocarcinoma 25, squamous cell carcinoma 10, small cell carcinoma 5) and 10 cases were benign lesions (tuberculoma 7, fungal ball 1, other inflammation 2). Results: The mean diameter of the target lesion was 35.4${\pm}$4.3 mm. Of the 50 patients examined, the overall diagnostic yield by EBUS-TBLB was 46.0% (23/50). The visualization yield of EBUS was 66.0% (33/50). A definitive diagnosis of PPL localized by EBUS was established using EBUS-TBLB in 69.6% (23/33) of cases. The diagnostic yields from washing cytology and brushing cytology from a bronchus identified by EBUS were 27.0% and 45.4% respectively. The diagnostic yields reached 78.7% when the three tests (washing cytology, brushing cytology and EBUS-TBLB) were combined. The visualization yield of EBUS in lesions <20 mm was significantly lower than that in lesions ${\geq}$20 mm (p=0.04). The presence of a bronchus leading to a lesion (open bronchus sign) on the chest CT scan was associated with a high visualization yield on EBUS (p=0.001). There were no significant complications associated with EBUS-TBLB. Conclusion: EBUS-TBLB is a safe and effective method for diagnosing PPL. The lesion size and open bronchus signs are significant factors for predicting the visualization of EBUS.

• KSBB Journal
• /
• v.21 no.3
• /
• pp.224-229
• /
• 2006

FEMLAB is a powerful interactive environment for modeling, solving all kinds of scientific and engineering problems based on partial differential equations(PDEs). Separation process of chiral compound in HPLC columns was simulated by FEMLAB. To study change of elution profile with isotherm models, non-competitive and competitive Langmuir adsorption isotherm were adopted. Separated material was (R, S)-ibuprofen [(R, S)-2-(4-isobutyl phenyl) propionic acid], an anti-inflammatory agent, which retain the pharmacological activity in the (S)-(+)-enantiomer. Sample concentrations were changed from 0.5 mg/ml to 2.0 mg/ml at a flow rate of 1 ml/min and flow rate varied from 1 ml/min to 3 ml/min at an ibuprofen concentration of 2.0 mg/ml and $20{\mu}l$ of injection volume. Simulated results were well fitted with experimental data.