• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.1-5
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• 2012

$Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ hollow fiber with o.d. 1.02 mm and i.d. 0.437 mm were fabricated by a phase-inversion spinning technique.The starting $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ precursor was synthesized by the polymerized complex method and then calcined at $900^{\circ}C$. As-prepared powder was dispersed in a polymer solution, and extruded as form of hollow fiber through a spinneret. Finallydense $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ hollow fiber membrane was obtained by sintering for 2 h at $1,080^{\circ}C$ for the application of oxygen separation. In addition, despite a very thin membrane with 0.58 mm, the BSCF hollow fiber membrane possessed a proper mechanical strength of 602.5 MPa.

• Journal of Korean Society of Forest Science
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• v.95 no.3
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• pp.282-290
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• 2006

Forest vegetation types were studied by the phytosociological investigation and the TWINSPAN method in Ulleung Island, Korea. Two hundred thirty-two releves were sampled with $100m^2$ plots. Two main vegetation types, the mountain forest(Acer okamotoanum community group) and maritime forest(Artemisia scoparia community group), have been distinguished and typified twenty-two vegetation units. The former was divided in 4 communities, 11 groups and 7 subgroups. The latter was 2 communities and 5 groups. In a case of life-forms of mountain and maritime vegetation type, the composition ratio of species that had featured trees and herbs, hemicrypthophyte, a seed dispersion-type by wind or nature falling and erection form was high in the mountain vegetation type. Species that had featured shrubs, chamaephyte, disseminated mainly by a wind in the herbs, and animals and man or no special modification in the woody, narrowest extent of rhizomatous growth and the clonal growth by stolons and struck roots and procumbent form were abundantly distributed in the maritime bluff vegetation type. Particularly, the composition ratio of Sambucus sieboldiana var. pendula community(A6), disturbed vegetation type of middle-lower slope of mountain, that had featured a seed dispersion-type by wind, moderate and narrowest extent of rhizomatous growth and Tussock form was high.

• Tuberculosis and Respiratory Diseases
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• v.49 no.5
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• pp.585-593
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• 2000

Background : International consensus guidelines have recently been developed to improve the assessment and management of asthma. One of the major recommendation of these guidelines is that asthma severity should be assessed through the recognition of key symptoms, such as nocturnal waking, medication requirements, and objective measurements of lung function. Differential classification of asthma severity would lead to major differences in both long term pharmacological management and the treatment of severe exacerbation. Methods : This study examined the relationship between the symptom score and measurements of $FEV_1$ and PEF when expressed as a percentage of predicted values in asthmatics (n=107). Results : The correlation of $FEV_1$ % with PEFR% was highly significant (r=0.83, p<0.01). However, there was agreement in terms of the classification of asthma severity in 76.6% of the paired measurements of $FEV_1$ % and PEFR%. Agreement in the classification of asthma severity was also found in 57.1% of the paired analysis of $FEV_1$ % and symptom score. 39% of the patients classified as having moderate asthma on the basis of $FEV_1$ % recording would be considered to have severe asthma if symptom score alone were used. Low baseline $FEV_1$ and high bronchial responsiveness were associated with a low degree of perception of airway obstruction. Conclusion : The relationships between the symptom score, PEFR and $FEV_1$ were generally poor. When assessing asthma severity, age, duration, $PC_{20}$, and baseline $FEV_1$ should be considered.

• Clean Technology
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• v.16 no.3
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• pp.198-205
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• 2010

Two sets of thermal reaction experiment for chlorinated hydrocarbons were performed using an isothermal tubular-flow reactor in order to investigate thermal decomposition, including product distribution of chlorinated hydrocarbons. The effects of $H_2$ or Ar as the reaction atmosphere on the thermal decomposition and product distribution for dichloromethane($CH_2Cl_2$) was examined. The experimental results showed that higher conversion of $CH_2Cl_2$ was obtained under $H_2$ atmosphere than under Ar atmosphere. This phenomenon indicates that reactive-gas $H_2$ reaction atmosphere was found to accelerate $CH_2Cl_2$ decomposition. The $H_2$ plays a key role in acceleration of $CH_2Cl_2$ decomposition and formation of dechlorinated light hydrocarbons, while reducing PAH and soot formation through hydrodechlorination process. It was also observed that $CH_3Cl,\;CH_4,\;C_2H_6,\;C_2H_4$ and HCl in $CH_2Cl_2/H_2$ reaction system were the major products with some minor products including chloroethylenes. The $CH_2Cl_2$/Ar reaction system gives poor carbon material balance above reaction temperature of $750^{\circ}C$. Chloroethylenes and soot were found to be the major products and small amounts of $CH_3Cl$ and $C_2H_2$ were formed above $750^{\circ}C$ in $CH_2Cl_2$/Ar. The thermal decomposition reactions of chloroform($CHCl_3$) with argon reaction atmosphere in the absence or the presence of $CH_4$ were carried out using the same tubular flow reactor. The slower $CH_3Cl$ decay occurred when $CH_4$ was added to $CH_3Cl$/Ar reaction system. This is because :$CCl_2$ diradicals that had been produced from $CHCl_3$ unimolecular dissociation reacted with $CH_4$. It appears that the added $CH_4$ worked as the :$CCl_2$ scavenger in the $CHCl_3$ decomposition process. The product distributions for $CHCl_3$ pyrolysis under argon bath gas were distinctly different for the two cases: one with $CH_4$ and the other without $CH_4$. The important pyrolytic reaction pathways to describe the important features of reagent decay and intermediate product distributions, based upon thermochemistry and kinetic principles, were proposed in this study.

• Tuberculosis and Respiratory Diseases
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• v.44 no.4
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• pp.822-835
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• 1997

Background : There have been many in vitro evidences that interleukin-4(IL-4) might be the most important cytokine inducing IgE synthesis from B-cells, and interferon-gamma(IFN-$\gamma$) might be a main cytokine antagonizing IL-4-mediated IgE synthesis. Recently some reports demonstrated that IFN-$\gamma$ might be used as a new therapeutic modality in some allergic diseases with high serum IgE level, such as atopic dermatitis or bronchial asthma. To evaluate the in vivo effect of IFN-$\gamma$ in bronchial asthma we tried a clinical study. Methods : Fifty bronchial asthmatics(serum IgE level over 200 IU/ml) who did not respond to inhaled or systemic corticosteroid treatment, and 17 healthy nonsmoking volunteers were included in this study. The CD 23 expressions of peripheral B-cells, the IL-4 activities of peripheral T-cells, the serum soluble CD23(sCD23) levels, and the superoxide anion(${O_2}^-$) generations by peripheral PMN were compared between bronchial asthmatics and normal subjects. The IL-4 activities of peripheral T-cells were analyzed by T-cell supernatant (T-sup)-induced CD23 expression from tonsil B-cells. In bronchial asthmatics the serum IgE levels and histamine $PC_{20}$ in addition to the above parameters were also compared before and after IFN-$\gamma$ treatment. IFN-$\gamma$ was administered subcutaneously with a weekly dose of 30,000 IU per kilogram of body weight for 4 weeks. Results : The ${O_2}^-$ generations by peripheral PMNs in bronchial asthmatics were higher than normal subjects($8.23{\pm}0.94$ vs $5.00{\pm}0.68\;nmol/1{\times}10^6$ cells, P<0.05), and significantly decreased after IFN-$\gamma$ treatment compared to initial values($3.69{\pm}0.88$ vs $8.61{\pm}1.53\;nmol/1{\times}10^6$ cells, P<0.05). CD23 expression of peripheral B-cells in bronchial asthmatics was higher than normal subjects($47.47{\pm}2.96%$, vs $31.62{\pm}1.92%$, P<0.05), but showed no significant change after IFN-$\gamma$ treatment. The serum sCD23 levels in bronchial asthmatics were slightly higher than normal subjects($191.04{\pm}23.3\;U/ml$ vs $162.85{\pm}4.85\;U/ml$), and 11(64.7%) of 17 patients showed a decreasing pattern in their serum sCD23 levels after IFN-$\gamma$ treatment. However the means of serum sCD23 levels were not different before and after IFN-$\gamma$ treatment. The IL-4 activities of peripheral T-cells in bronchial asthmatics were slightly higher than normal subjects($22.48{\pm}6.81%$ vs $18.90{\pm}2.43%$), and slightly increased after IFN-$\gamma$ treatment($27.90{\pm}2.56%$). Nine(60%) of 15 patients showed a decreasing pattern in their serum IgE levels after IFN-$\gamma$ treatment. And the levels of serum IgE were significantly decreased after IFN-$\gamma$ treatment compared to initial values ($658.67{\pm}120.84\;IU/ml$ vs $1394.32{\pm}314.42\;IU/ml$, P<0.05). Ten(83.3%) of 12 patients showed an improving pattern in bronchial hyperresponsiveness after IFN-$\gamma$ treatment, and the means of histamine $PC_{20}$ were significantly increased after IFN-$\gamma$ treatment compared to initial values ($1.22{\pm}0.29mg/ml$ vs $0.69{\pm}0.17mg/ml$, P<0.05). Conclusion : Our results suggest that IFN-$\gamma$ may be useful as well as safety in the treatment of bronchial asthmatics with high serum IgE level and that in vivo effects of IFN-$\gamma$ may be different from its in vitro effects on the regulations of IgE synthesis or the respiratory burst of PMN.

• Tuberculosis and Respiratory Diseases
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• v.45 no.6
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• pp.1236-1251
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• 1998

Background : TNF-$\alpha$ appears to be a central mediator of the host response to sepsis. While TNF-$\alpha$ is mainly considered a proinflammatory cytokine, it can also act as a direct cytotoxic cytokine. However, there are not so many studies about the relationship bet ween TNF-$\alpha$ level and lung injury severity in ALI, particularly regarding the case of ALI caused by direct lung injury such as diffuse pulmonary infection. Recently, a natural defense mechanism, known as the stress response or the heat shock response, has been reported in cellular or tissue injury reaction. There are a number of reports examining the protective role of pre-induced heat stress proteins on subsequent LPS-induced TNF-$\alpha$ release from monocyte or macrophage and also on subsequent LPS-induced ALI in animals. However it is not well established whether the stress protein synthesis such as HSP can be induced from rat alveolar macrophages by in vitro or in vivo LPS stimulation. Methods : We measured the level of TNF-$\alpha$, the percentage of inflammatory cells in bronchoalveolar lavage fluid, protein synthesis in alveolar macrophages isolated from rats at 1, 2, 3, 4, 6, 12, and 24 hours after intratracheal LPS instillation. We performed histologic examination and also obtained histologic lung injury index score in lungs from other rats at 1, 2, 3, 4, 6, 12, 24 h after intratracheal LPS instillation. Isolated non-stimulated macrophages were incubated for 2 h with different concentration of LPS (0, 1, 10, 100 ng/ml, 1, or 10 ${\mu}g/ml$). Other non-stimulated macrophages were exposed at $43^{\circ}C$ for 15 min, then returned to at $37^{\circ}C$ in 5% CO2-95% for 1 hour, and then incubated for 2 h with LPS (0, 1, 10, 100ng/ml, 1, or 10 ${\mu}g/ml$). Results : TNF-$\alpha$ levels began to increase significantly at 1 h, reached a peak at 3 h (P<0.0001), began to decrease at 6 h, and returned to control level at 12 h after LPS instillation. The percentage of inflammatory cells (neutrophils and alveolar macrophages) began to change significantly at 2 h, reached a peak at 6 h, began to recover but still showed significant change at 12 h, and showed insignificant change at 24 h after LPS instillation compared with the normal control. After LPS instillation, the score of histologic lung injury index reached a maximum value at 6 h and remained steady for 24 hours. 35 kDa protein band was newly synthesized in alveolar macrophage from 1 hour on for 24 hours after LPS instillation. Inducible heat stress protein 72 was not found in any alveolar macrophages obtained from rats after LPS instillation. TNF-$\alpha$ levels in supernatants of LPS-stimulated macro phages were significantly higher than those of non-stimulated macrophages(p<0.05). Following LPS stimulation, TNF-$\alpha$ levels in supernatants were significantly lower after heat treatment than in those without heat treatment (p<0.05). The inducible heat stress protein 72 was not found at any concentrations of LPS stimulation. Whereas the 35 kDa protein band was exclusively found at dose of LPS of 10 ${\mu}g/ml$. Conclusion : TNF-$\alpha$ has a direct or indirect close relationship with lung injury severity in acute lung injury or acute respiratory distress syndrome. In vivo and in vitro LPS stimulation dose not induce heat stress protein 72 in alveolar macrophages. It is likely that 35 kDa protein, synthesized by alveolar macrophage after LPS instillation, does not have a defense role in acute lung injury.