소결 경질 탄화물에 화학 증착법으로 TiC 를 증착시킬때 그들의 성질에 관한 연구

이채우,이동복,천성순,김재곤 대한금속재료학회(대한금속학회) 1980 대한금속·재료학회지 Vol.18 No.5

화학 증차법을 이용하여 WC-Co합금의 substrate위에 TiC를 증착시킬때 coating층의 성장과 내마모성질을 조사하였다. 증착온도 및 시간, substrate의 Co함량이 증가할수록 coating층의 두께는 현저한 증가를 보였으며 증착온도가 증가함에 따라 우선방위는 <100>으로부터 random orientation을 나타내었다. TiC coating한 시편은 내마모저항을 현저히 증가시켰으며 이에 대한 원인도 논하였다. Growth of coating layer and wear properties of chemically vapor deposited (CVD) TiC onto WC-Co substrate were investigated. The deposition temperature, time and Co content of the substrate showed pronounced effects on the thickness of coating layer. The texture of TiC layer changed from <100> orientation at low deposition temperature (950℃) to random orientation at high deposition temperature (1050℃). The wear resistance of coated specimen was remarkably increased and enhanced wear resistance was also discussed.

암에르고미터 운동시 여유심박수에서의 신체작업능력(PWC%HRR)을 이용한 최대산소섭취량 추정에 관한 연구

정성태,전태원,정덕조,정영수,엄우섭,이동기,윤호섭 한국운동과학회 2000 운동과학 Vol.9 No.1

암에르고미터 운동시 여유심박수에서의 신체작업능력(PWC%HRR)을 이용한 최대산소섭취량 측정에 관한 연구 운동과학. 제 9권 제 1호. (1)-(12), 2000. 본 연구의 목적은 암에르고미터 운동시 여유심박수에서의 신체작업능력(PWC%HRR)을 이용해 최대산소섭취량(O₂_(max))을 추정하는데 있어 그 타당성을 보는데 있다. 이를 위해 본 연구에서는 건강한20대 남자 대학생(21.1±2.77)20명이 참가 하였다. 이들의 안정시 심박수는 5분간 EKG로 측정되었고, 최대산소취량은 암에르고미터에서 50rpm의 속도로 20W에서 운동을 실시하고 매 3분 간격으로 10W씩 증가시켜 피험자가 탈진시까지 운동을 지속시켰다. 여유심박수 계산에 있어서 최대심박수는 수식(HRmax = 210 - age)으로 계산되었다. PWC%HRR의 계산은 점증부하 운동상에서 120≤R≥160의 범위에 발견된 HR과 O₂의 관계식(Y=bx+a)에 의하였다. 강도별 상대적 백분율 범위는 50∼85%사이였으며, 비교대상은 PWC%HRR, O₂R, O₂_(max)이었다. 그 결과 다음과 같은 결과를 얻었다 첫째, %HRR과 O₂R, O₂_(max)간의 회귀분석결과 %HRR은 O₂_(max)보다 O₂R에 가까웠다. 둘째, 각 강도별 PWC%HRR과 O₂R, O₂_(max)간에는 통계적으로 유의한 차이는 없었으나, PWC%HRR은 O₂_(max)보다 O₂R에 보다 가까웠다(P<.05). 셋째, O₂_(max)의 실측치와 PWC%HRR = O₂R에 의한 추정치 사이에는 모든 강도에서 통계적으로 유의한 차이가 없었으나, 상관관계는 PWC%HRR에서 가장 높았다(P<.05). 이상의 결과를 종합해 볼 때 암에르고미터 운동검사 과정에서 만족할 만한 O₂_(max) 발견하지 못했더라도 최소한 60%HRR에 해당하는 심박수가 발견될 때까지 운동을 수행하였다면 일련의 방식에 의해 O₂_(max)의 추정이 가능하다고 본다. The study on Estimation of maximal oxygun uptake through PWC%HRR during Arm Ergometer Exercise. Exercise Science, 9(1): 1-12, 2000. The purpose of this study was to evaluate the validity for estimation of maximal oxygen uptake through PWC%HRR during Arm Ergometer Exercise. The subjects of this study were 20 healthy males(21.2±2.77yrs) college students. Resting heart rate of subjects were recorded by EKG for 5min. the maximal oxygen uptake was determined until subjects were exhausted. The first stage was performed 50rpm, 20W, and then was increased by 10W every 3 minutes on the arm ergometer. HRmax was determined by a numerical formula of HRmax = 210-age. PWC%HRR was assessed by relative equation (Y=bX+a) of HR and V˙O₂ observed in range 120≤R≥160 during the exercise test. Range of relative percentage was between 50% and 85%, comparison factor was examined among PWC%HRR, % V˙O₂R and % V˙O₂_(max). The results of this study are as follows : 1) Result of the regression analysis among PWC%HRR, % V˙O₂R and % V˙O₂_(max), %HRR was equivalent to % V˙O₂R rather than V˙O₂_(max). 2) No significant difference was observed among PWC%HRR, % V˙O₂R and V˙O₂_(max) in the all intensity, But the PWC%HRR was closer to % V˙O₂R rather than V˙O₂_(max)(P<.05). 3) No significant difference was the actual V˙O₂_(max) and the estimation value by PWC%HRR = % V˙O₂R in the all intensity, and the correlation analysis was the most correlated at the estimation value by PWC%60HRR. It was concluded that if the satisfactory V˙O₂_(max) was not found in Arm Ergometer exercise test but heart rate corresponded to 60%HRR, V˙O₂_(max) can be estimated by a series of equation.

Macromer 를 기초로 한 폴리우레탄의 합성 및 특성

전용철,김공수,신재섭,강석호 한국고무학회 1992 엘라스토머 및 콤포지트 Vol.27 No.3

A series of polyurethane block copolymers based on hydroxyterminated poly(dimethyl siloxane), poly(propylene glycol) and poly(tetramethylene glycol) soft segments of molecular weights 1,809, 2,000 and 2,000, respectively, were synthesized. The hard segments consisted of 4,4'-diphenylmethane diisocyanate and 1,4-butanediol as the chain extender. Samples with different molar ratios were prepared. We tried to synthesize poly(dimethyl siloxane)-based polyurethane(PDMS-PU) containing a hard block as major fraction and a soft block as minor fraction for preparing toughened rigid systems. After a study of the pure PDMS-PU, poly(propylene glycol)-based polyurethane(PPG-PU) and poly(tetramethylene glycol)-based polyurethane(PTMG-PU), (mixed polyol)-based block copolymers and blends between PDMS-PU, PPG-PU and PTMG-PU were prepared, and characterized by means of differential scanning calorimetry, tensile testing and scanning electron microscopy. In (mixed polyol)-based PU and in lower hard segment content blends, macro-phase separation was shown, but blends with higher hard segment contents showed significant reduction in amounts of phase separation.

Bourneville Pringle Phancomatoses 의 1 예

전세현 대한피부과학회 1965 大韓皮膚科學會誌 Vol.4 No.1

Sources, distribution, bioavailability, toxicity, and risk assessment of heavy metal(loid)s in complementary medicines

Bolan, Shiv,Kunhikrishnan, Anitha,Seshadri, Balaji,Choppala, Girish,Naidu, Ravi,Bolan, Nanthi S.,Ok, Yong Sik,Zhang, Ming,Li, Chun-Guang,Li, Feng,Noller, Barry,Kirkham, Mary Beth Elsevier 2017 Environment international Vol.108 No.-

<P><B>Abstract</B></P> <P>The last few decades have seen the rise of alternative medical approaches including the use of herbal supplements, natural products, and traditional medicines, which are collectively known as ‘Complementary medicines’. However, there are increasing concerns on the safety and health benefits of these medicines. One of the main hazards with the use of complementary medicines is the presence of heavy metal(loid)s such as arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg). This review deals with the characteristics of complementary medicines in terms of heavy metal(loid)s sources, distribution, bioavailability, toxicity, and human risk assessment. The heavy metal(loid)s in these medicines are derived from uptake by medicinal plants, cross-contamination during processing, and therapeutic input of metal(loid)s. This paper discusses the distribution of heavy metal(loid)s in these medicines, in terms of their nature, concentration, and speciation. The importance of determining bioavailability towards human health risk assessment was emphasized by the need to estimate daily intake of heavy metal(loid)s in complementary medicines. The review ends with selected case studies of heavy metal(loid) toxicity from complementary medicines with specific reference to As, Cd, Pb, and Hg. The future research opportunities mentioned in the conclusion of review will help researchers to explore new avenues, methodologies, and approaches to the issue of heavy metal(loid)s in complementary medicines, thereby generating new regulations and proposing fresh approach towards safe use of these medicines.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A first-time comprehensive overview on the health risk assessment of heavy metal(loid)s in complementary medicines </LI> <LI> Ayurvedic medicines contain toxic levels of heavy metal(loid)s including As, Cd, Hg and Pb </LI> <LI> The bioavailability of metal(loid)s in complementary medicines depends on speciation of these metals </LI> <LI> Regular intake of some complementary medicines has caused metal(loid) toxicity in humans </LI> <LI> Health risk assessment can be achieved based on the daily intake of complementary medicines and total metal(loid) content </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Interactions between heavy metal(loid)s and complementary medicines.</P> <P>[DISPLAY OMISSION]</P>

국산박류의 사료가치에 관한 연구 2 . 부로일러에 대한 박류비교시험

백인기,한인규,김춘수 ( In K . Paik,In K . Han,Chun S . Kim ) 한국축산학회 1975 한국축산학회지 Vol.17 No.4

An experiment was conducted to study the comparative feeding value of locally produced vegetable protein cakes such as soybean oil meal (44%) (S.B.O.M.), rapeseed oil meal (R.O.M.), perilla oil meal (P.O.M.), sesame oil meal (S.O.M.) and corn gluten (50%). Three hundred broiler chickens were used for 8 weeks feeding trial and successive metabolic tiral. Results obtained are as follows; 1. Weight gains were significantly (P$lt;0.01) different among treatments showing the best gain in S.B.O.M. group and then P.O.M., R.O.M., corn gluten and S.O.M. group in that order. Feed intake showed same trend as weight gain did. For the feed efficiency, S.B.O.M. group was significantly (P$lt;0.01) superior to the other groups and S.O.M. group was significantly inferior to the other groups. Among the groups of receiving R.O.M., P.O.M. and corn gluten, differences were not significant each other in feed efficiency. 2. Amino acids compositions of R.O.M. and S.B.O.M. were better than that of other protein feeds considering their relatively high E.A.A. Index of 76.32 and 76.21 respectively. P.O.M., S.O.M. and corn gluten were low in lysine content while methionine contents were relatively high. 3. Nitrogen corrected M.E. values of S.B.O.M., R.O.M., P.O.M., S.O.M. and corn gluten were 2,367㎉, 843㎉, 2.234㎉, 1,305㎉ and 4,283㎉, respectively. Rates of nitrogen retention of P.O.M., S.B.O.M., R.O.M., corn gluten and S.O.M. were 59.38%, 51.18%, 54.11%, 44.80%, and 36.01%, respectively. 4. Dry matter and crude protein availabilities of finisher diet of R.O.M. group and S.B.O.M. group were higher than that of other groups but not significantly different. On the contrary however, crude fat availabilities of R.O.M., and S.B.O.M. group were significantly (P$lt;0.01) lower than that of other groups. 5. Thyroid gland weights and total serum cholesterol contents were significantly (P$lt;0.05) different among treatments. However, the relationship between thyroid gland weight and cholesterol content was observed only in R.O.M. group. Corn gluten was verb effective to increase skin pigmentation. 6. Production cost for 1㎏ of broiler meat of S.B.O.M. group was lower by about 20 won to 30won than that of R.O.M., corn gluten, or P.O.M. group, and by about 100won than that of sesame oil meal group which was least for the performance among the treatments.

Prurigo Pigmentosa: A Report of 5 Cases with a Review of the Korean Literature

Chun, Y. S Korean Dermatological Association 1998 Annals of Dermatology Vol.10 No.2

Purification and characterization of a novel fibrinolytic α chymotrypsin like serine metalloprotease from the edible mushroom, Lyophyllum shimeji

Moon, S.M.,Kim, J.S.,Kim, H.J.,Choi, M.S.,Park, B.R.,Kim, S.G.,Ahn, H.,Chun, H.S.,Shin, Y.K.,Kim, J.J.,Kim, D.K.,Lee, S.Y.,Seo, Y.W.,Kim, Y.H.,Kim, C.S. Society for Bioscience and Bioengineering, Japan ; 2014 Journal of bioscience and bioengineering Vol.117 No.5

A novel fibrinolytic enzyme was purified from Lyophyllum shimeji, a popular edible mushroom in Asia. The enzyme was purified using combination of anion exchange chromatography on a Mono Q 5/5 column and size exclusion gel filtration chromatography on Superdex 200 100/300 column. This purification protocol resulted 80.9-fold purification of the enzyme and a final yield of 5.7%. The molecular weight of the purified enzyme was estimated to be 21 kDa by SDS-PAGE and size exclusion gel filtration. The N-terminal amino acid sequence was found to be ITFQSASP, which is dissimilar from that of known fibrinolytic enzymes. The purified enzyme was a neutral protease with an optimal reaction pH and temperature of 8.0 and 37<SUP>o</SUP>C, respectively. Enzymatic activity was inhibited by Cu<SUP>2+</SUP> and Co<SUP>2+</SUP>. It was also significantly inhibited by PMSF and TPCK. Furthermore, it was found to exhibit a higher specificity for S-7388, a well-known chymotrypsin chromogenic substrate, indicating chymotrypsin like serine metalloprotease. The relative fibrinolytic activity of 5 μg purified enzyme have two fold more activity than 1 unit/ml of plasmin on fibrin plate. Furthermore, purified enzyme preferentially hydrolyzed the Aα-chain followed by the Bβ- and γ-chain of fibrinogen, which is precursor of fibrin. Therefore, these data suggests that the fibrinolytic enzyme derived from edible mushroom, L. shimeji, might be useful for thrombolytic therapy and preventing thrombotic disease.

Biochemical analysis of recombinant CYP4A11 allelic variant enzymes: W126R, K276T and S353G

Han, S.,Cha, G.S.,Chun, Y.J.,Lee, C.H.,Kim, D.,Yun, C.H. JAPANESE SOCIETY FOR THE STUDY OF XENOBIOTICS 2016 DRUG METABOLISM AND PHARMACOKINETICS Vol.31 No.6

Human CYP4A11 is the major ω-hydroxylase of fatty acids in the liver and kidneys. It produces 20-hydroxyeicosatetraenoic acid as well as hydroxylates fatty acids. In this study, we investigated the biochemical properties of three alleles of CYP4A11: W126R, K276T, and S353G. Site-directed mutagenesis of the wild type CYP4A11 was performed, to construct the W126R, K276T, and S353G variant clones. The CYP4A11 wild type and variant constructs were heterologously expressed in Escherichia coli. CO-binding spectra showed the expression of the wild type, K276T and S353G variants, indicating the functional P450 holoenzyme. The W126R variant was not expressed in E. coli. Binding affinities of lauric acid in K276T and S353G variants were stronger than that of wild type. Steady-state kinetics in the hydroxylation reaction of fatty acids were studied. The catalytic efficiencies (k<SUB>cat</SUB>/K<SUB>m</SUB>) of K276T and S353G variants in the reactions without cytochrome b<SUB>5</SUB> were approximately 2- and 4-fold higher, respectively, than that of wild type, and in the reactions with cytochrome b<SUB>5</SUB> they were approximately 2- and 3-fold higher, respectively. These results suggest that individuals carrying the alleles, K276T and S353G, might exhibit higher catalysis of CYP4A11, which may affect the endogenous metabolic products associated with regulation of blood pressure.

Movement-Related Sensorimotor High-Gamma Activity Mainly Represents Somatosensory Feedback

Ryun, Seokyun,Kim, June S.,Jeon, Eunjeong,Chung, Chun K. Frontiers Media S.A. 2017 Frontiers in neuroscience Vol.11 No.-

<P>Somatosensation plays pivotal roles in the everyday motor control of humans. During active movement, there exists a prominent high-gamma (HG >50 Hz) power increase in the primary somatosensory cortex (S1), and this provides an important feature in relation to the decoding of movement in a brain-machine interface (BMI). However, one concern of BMI researchers is the inflation of the decoding performance due to the activation of somatosensory feedback, which is not elicited in patients who have lost their sensorimotor function. In fact, it is unclear as to how much the HG component activated in S1 contributes to the overall sensorimotor HG power during voluntary movement. With regard to other functional roles of HG in S1, recent findings have reported that these HG power levels increase before the onset of actual movement, which implies neural activation for top-down movement preparation or sensorimotor interaction, i.e., an efference copy. These results are promising for BMI applications but remain inconclusive. Here, we found using electrocorticography (ECoG) from eight patients that HG activation in S1 is stronger and more informative than it is in the primary motor cortex (M1) regardless of the type of movement. We also demonstrate by means of electromyography (EMG) that the onset timing of the HG power in S1 is later (49 ms) than that of the actual movement. Interestingly, we show that the HG power fluctuations in S1 are closely related to subtle muscle contractions, even during the pre-movement period. These results suggest the following: (1) movement-related HG activity in S1 strongly affects the overall sensorimotor HG power, and (2) HG activity in S1 during voluntary movement mainly represents cortical neural processing for somatosensory feedback.</P>