Analysis method for determination of nisin A and nisin Z in cow milk by using liquid chromatography-tandem mass spectrometry

Ko, K.Y.,Park, S.R.,Lee, C.A.,Kim, M. American Dairy Science Association 2015 Journal of dairy science Vol.98 No.3

Nisin, a polypeptide with antimicrobial properties, is known as a natural preservative. It is used in various foods, including dairy products. This study validated a novel procedure using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of nisin A and nisin Z in cow milk. An extraction solution of 0.1 M acetate buffer containing 1 M NaCl (pH 2.0) and MeOH (1:1) was used to extract nisin A and nisin Z from milk samples. After the addition of extraction buffers, the samples were homogenized and centrifuged. The supernatant was filtered and injected for LC-MS/MS analysis. The linearity of the analytical method had a high correlation coefficient (r≥0.9987). The limits of quantitation of nisin A and nisin Z were approximately 12.9 and 10.9 @?g/kg, respectively. The accuracy of the analytical method in milk ranged from 90.6 to 103.4% for nisin A and from 83.8 to 104.4% for nisin Z. The coefficient of variation values of intra- and interday in milk determined to be less than 5% in both nisin A and nisin Z. Because the proposed method has comparatively high recovery and low coefficient of variation, it seems appropriate for the determination of nisin A and nisin Z in milk samples. As the quantification of nisin A and nisin Z in milk samples by using LC-MS/MS has only been rarely reported until now, this study provides a meaningful technological advance for the dairy industry.

Development of titanium oxide layer containing nanocrystalline zirconia particles with tetragonal structure: Structural and biological characteristics

Shin, K.R.,Kim, Y.S.,Kim, G.W.,Ko, Y.G.,Shin, D.H. Elsevier 2015 Colloids and Surfaces B Vol.131 No.-

This study investigated the microstructural, mechanical and biological properties of oxide layers containing tetragonal zirconia (t-ZrO<SUB>2</SUB>) particles on pure titanium produced by plasma electrolytic oxidation (PEO) process. For this purpose, PEO processes were carried out at an AC current density of 200mA/cm<SUP>2</SUP> for 180s in potassium pyrophosphate (K<SUB>4</SUB>P<SUB>2</SUB>O<SUB>7</SUB>) electrolytes with and without t-ZrO<SUB>2</SUB> powder. Structural investigations using transmission electron microscopy exhibited that the present nanocrystalline oxide layer evidenced the successful incorporation of a myriad of t-ZrO<SUB>2</SUB> particles working as an intermediate medium to reinforce the adhesion strength between the substrate and oxide layer. Regarding biomimetic apatite formation, the t-ZrO<SUB>2</SUB> particles uniformly spread were of considerable importance in triggering the nucleation and growth of biomimetic apatite on the surface of the oxide layer immersed in a simulated body fluid solution. The growth and proliferation rates of the osteoblasts (MC3T3-E1) cultured on the oxide layer with t-ZrO<SUB>2</SUB> particles were higher than that without t-ZrO<SUB>2</SUB> particles due to the higher roughness providing the better sites for the filopodia extension and interlocking.

Point-Collocation Non-intrusive Polynomial Chaos 기법을 활용한 평판 주위 난류 유동장 해석

장경식(K. Chang),고아림(A.R. Ko) 한국전산유체공학회 2018 한국전산유체공학회지 Vol.23 No.2

In the present work, uncertainty quantification based on the point-collocation Non-intrusive Polynomial Chaos was studied in turbulent flow around the flat plate using Menter’s SST k-ω model. Two random variables of β* , model coefficient of Menter’s SST k-ω model and U<SUB>∞</SUB>, the freestream velocity are considered. β*, model coefficient was assumed to be uniformly distributed and the freestream velocity U<SUB>∞</SUB>, normally distributed with a certain value of variance. First, the uncertainty quantification with the single random variable of each one was simulated for sensitivity analysis of each parameter on the outputs such as drag coefficient and skin friction one. When the normal distribution of freestream velocity is considered, the drag coefficient showed the same type of distribution with 0.9% standard deviation. The uniform distribution of β* with the internals of 0.0784 and 0.1024 had an effect on 5% variance on drag coefficient. When two random variables are considered simultaneously, the distribution of drag coefficient showed closer type with one of model coefficient β* .The convergence rate of mean value was late than that with single random variable and standard deviation was not converged until the 5th order of gPC.

Surface characteristics and biological response of titanium oxide layer formed via micro-arc oxidation in K₃PO₄ and Na₃PO₄ electrolytes

Jung, Y.C.,Shin, K.R.,Ko, Y.G.,Shin, D.H. Elsevier Sequoia 2014 JOURNAL OF ALLOYS AND COMPOUNDS Vol.586 No.suppl1

The present work demonstrated the influence of phosphate electrolytes on surface characteristics and biological response of the titanium oxide layer formed via micro-arc oxidation coating. For this purpose, the present coatings were carried out on titanium samples using two different electrolytes containing Na<SUB>3</SUB>PO<SUB>4</SUB> and K<SUB>3</SUB>PO<SUB>4</SUB>. The surface roughness of the oxide layer formed in K<SUB>3</SUB>PO<SUB>4</SUB> electrolyte was higher than that in the Na<SUB>3</SUB>PO<SUB>4</SUB> electrolyte. This was attributed to the higher fraction of the micropores in the oxide layer prepared by the K<SUB>3</SUB>PO<SUB>4</SUB> electrolyte than that by the Na<SUB>3</SUB>PO<SUB>4</SUB> electrolyte. From the results of simulated body fluid test, the precipitation and growth of amorphous calcium phosphate on the oxide layer formed in the K<SUB>3</SUB>PO<SUB>4</SUB> electrolyte was superior to that in the Na<SUB>3</SUB>PO<SUB>4</SUB> electrolyte due to the enhanced surface roughness. In addition, in vitro cell adhesion was triggered in case of the oxide layer formed in the K<SUB>3</SUB>PO<SUB>4</SUB> electrolyte.

$YBa_2CU_3O_{7-\delta}$ coated Conductor 완충층으로의 응용을 위한 $SrTiO_3 $ 박막의 성장 조건

정준기,고락길,송규정,박찬,김철진,Chung, J.K.,Ko, R.K.,Song, K.J.,Park, C.,Kim, C.J. 한국결정학회 2003 韓國結晶學會誌 Vol.14 No.2

YBa₂CU₃O/sub 7-8/(YBCO) coated conductor의 완충층 구조를 개선하기 위하여 2축배향된 Ni-3 wt%W 합금 기판위에 단일 완충층으로 SrTiO₃(STO) 박막을 증착하였다. YBCO와 STO 박막은 펄스레이저 증착법으로 성장시켰다. STO 박막의 표면은 증착온도에 따라 다른 미세조직을 보여 주었고, XRD 분석에서는 STO와 YBCO 박막이 금속기판의 배향성을 가지면서 성장되었음을 알 수 있었다. 액체질소 온도에서 1.2 MA/㎠의 임계전류밀도와 86 K의 임계온도를 가지는 짧은 길이의 coated conductor를 STO 단일완충층을 이용하여 제조하였다. SrTiO₃ (STO) thin fims were deposited on the biaxially textured Ni-3 wt%W alloy substrates to be used as a single buffer layer for YBa₂CU₃O/sub 7-8/(YBCO) coated conductor. Thin films of YBCO and STO were deposited using pulsed laser. The deposition condition for epitaxial growth of STO on the textured metal was identified, and YBCO coated conductor with a single STO buffer layer with critical current density of 1.2 MA㎠ at 77 K under zero magnetic field and critical temperature of 86 K, was fabricated.

Emergence of an extended-spectrum <i>β</i>-lactamase-producing serotype K1 <i>Klebsiella pneumoniae</i> ST23 strain from Asian countries

CHEONG, H. S.,CHUNG, D. R.,PARK, M.,KIM, S. H.,KO, K. S.,HA, Y. E.,KANG, C. I.,PECK, K. R.,SONG, J. H. Cambridge University Press 2017 Epidemiology and infection Vol.145 No.5

<B>SUMMARY</B><P>Extended-spectrum <I>β</I>-lactamase (ESBL) production has been very rare in serotype K1 <I>Klebsiella pneumoniae</I> ST23 strains, which are well-known invasive community strains. Among 92 ESBL-producing strains identified in 218 isolates from nine Asian countries, serotype K1 <I>K. pneumoniae</I> strains were screened. Two ESBL-producing <I>K. pneumoniae</I> isolates from Singapore and Indonesia were determined to be serotype K1 and ST23. Their plasmids, which contain CTX-M-15 genes, are transferable rendering the effective transfer of ESBL resistance plasmids to other organisms.</P>

옥수수 - 산란계분 SILAGE 의 면양체내 소화율과 질소출납 및 반추위 성상에 관한 연구 - 2 . 옥수수 - 산란계분 SILAGE 의 면양체내 반추위 성상

고영두,김재황,류영우,강한석,유성오,강경록 경상대학교 축산진흥연구소 1996 畜産振興硏究所報 Vol.23 No.1

未熟兒 및 低體重新生兒에 關한 通計的 考察

韓禮澤,皮守英,高光昱 대한소아과학회 1970 小兒科 Vol.13 No.12

多發性骨髓腫의 臨床的 觀察

허규열,고행일,김성연,고일향,김예회 인제대학교 1980 仁濟醫學 Vol.1 No.2

1977년 8월부터 1980년 7월까지 인제의대 부속 백 병원에서 13예의 자발성 골수종 환자를 관찰한 바 남녀의 비는 1.8 : 1이었으며 남자의 평균 연령은 51.4세, 여자의 평균 연령은 53.6세였다. 임상증상은 골동통이 77%에서 있었으며 류마치스성관절염, 퇴행성관절염, 신질환등으로 초진된 경우가 많았다. 혈액소견상 빈혈이 92%에서, 증가된 적혈구침강속도가 전체환자에서, 말초혈액소견상 형질세포화한 림파구가 31%에 있었다. 생화학검사는 총단백의 증가가 62%, 고칼슘혈증이 31%, 질소혈증이 69%, 고뇨산증이 89%, hypergammaglobulinemia가 38%에서 나타났다. 12예에서 전기영동을 시행한 결과 M-단백이 γ-region에 8예, β-region 3예, α2-region에 1예로 나타났다. 면역전기영동은 9예에서 시행결과 IgG 44%, IgA 22%, IgD 22%, light chain 11%였다. 방사선과적 검사는 85%에서 골용성병변이 있었으며 두개골 척추골 늑골 골반등의 순으로 있었다. 치료는 melphalan+prednisone이나 cyclophosphamide+prednisone을 사용하여 좋은 결과를 얻을 수 있었으며 melphalan 또는 cyclphosophamide 등의 alkylating agent와 prednisone 병용에 반응을 보이지 않은 환자에서는 제 2차적인 치료법으로 CCNU, Adriamycin 및 vincrstine을 이용한 병용요법을 시행하여 효과를 보았다. From August 1977 to July 1980, thirteen cases of multiple myeloma had been admitted to Paik Hospital, Inje Medical College. The ratio of male to female was 1.8 1 and the mean age was 51.4 years old in man and 53.6 years old in woman. The most common clinical findings were bone pain and tenderness. There were many cases which had been impressed as rheumatoid arthritis, degenerative arthritis, or renal problem at first medical examination. Hematologic findings were anemia in 92%, elevated E.S.R. in 100%, and plasmacytoid lymphocyte in 31%. Blood chemistry showed increased total protein in 62%, azotemia in 69%, hyperuricemia in 89%, hyperglobulinemia in 38%, and hypercalcemia in 31%. Serum protein electrophoresis in 12 cases revealed that M-spike was present in γ-region in 8 cases, in β-region in 3 cases and in α2-region in one case. Immunoelectrophoresis in 9 cases showed Ig G in 44%, Ig A in 22%, Ig D in 22% and light chain in 11%. Osteolytic lesions were noted in 85% and involed skull, spine and ribs in order. All 13 patients were treated with alkylating agent (melphalan or cyclophosphamide) and prednisone. Patients, who did not show response to the alkylating agent, were treated with CCNU, Adriamycin and vincristine in combination. Of 13 patients, six patients were lost to follow-up. One patient who had severe renal failure at the tinge of admission was dead during chemotherapy in conjuction with dialysis. Three patients survived 11, 13 and 32 moths each. The remaining three patients are still alive and well from 3+ months to 25+ months after initiation of chemotherapy.

7β-〔2-Ethoxymethyl-3-(5-Nitro-2-Furyl) Acryl〕Aminocephalosporanic Acid의 合成 및 抗菌作用에 關한 硏究

金京洙,金永秀,洪石淳,高玉鉉,姜馨龍 조선대학교 약학연구소 1991 藥學硏究誌 Vol.13 No.1

7β〔2-Ethoxymethyl-3-(5-nitro-2-furyl) acryl〕aminocephalosporin was synt hesized by condensation of 7-Aminocephalosporanic acid(7-ACA) with 2-Ethoxymethyl-3 (5-nitro-2-furyl) acrylchloride. This compound was tested for antimicrobial activity in vitro against nine species of bacteria, such as Bacillus licheniformis ATCC 14580, Bacillus subtillus ATCC 6633, Candida albicans ATCC 10231, Escherichia coli ESS, Micrococcus luteus ATCC 9311, Pseudomonas aeruginosa IFO 13130, Staphylococcus aureus ATCC 25923, Staphylococcus aureus FDA 209p and Salmonella typhimurium SL 1102. This compound revealed significant antibacterial activity against Bacillus subtilis ATCC 6633 and Micrococcus luteus ATCC 9341, but showed less antimicrobial activity than cephradine and cefazoline for other microorganisms.