• Title/Summary/Keyword: AT&T

Search Result 29,607, Processing Time 0.054 seconds

Effects of Cultivation Conditions on the Growth and Polyamine Composition in Methylobacterium extorquens AM1 Growing on Methanol (Methylobacterium extorquens AM1의 메탄올을 이용한 성장과 세포내 폴리아민 구성에 미치는 배양조건의 영향)

  • 엄치용;박기정;강빈구;김영민
    • Korean Journal of Microbiology
    • /
    • v.29 no.6
    • /
    • pp.387-391
    • /
    • 1991
  • Methylobacterium extorquens AM1 growing on methanol as a sole source of carbon and energy was found to grow most rapidly (t$t_{d}$ =6h) at 30.deg.C in a mineral medium (pH 7.0) containing 0.5% (v/v) methanol which was agitated at 200 rpm (optimal cultivation condition). Cells grown under the optimal cultivation condition contained more spermidine, but less putrescine, than the cells grown on 2.5%(v/v) ( $t_{d}$ =8h ) or at 20.deg.C ( $t_{d}$ =8h ). Cells cultivated under the optimal condition was found to contain more spermidine than the cells grown at pH 6.0 (( $t_{d}$ =7h ) and pH 8.0 ($t_{d}$ =7.3h). the cells growing at the stationary phase under the optimal condition accumulated more spermine or putrescine than the cells growing at the same phase on 2.5%(v/v) methanol or at pH 6.0 and pH 8.0, respectively. M. extorquens AM1 grown in a medium agitated at 100 rpm ( $t_{d}$ =8.8h ) contained less spermidine and spermine than the cells grown under the optimal cultivation condition.

  • PDF

A Periodic Replacement Model with Random Repair Costs and Threshold Levels (확률적 수리비용과 임계수준을 고려한 주기적 교체 모형에 관한 연구)

  • Gang Yeong-Gil;Gang Seong-Jin
    • Journal of the military operations research society of Korea
    • /
    • v.18 no.2
    • /
    • pp.114-125
    • /
    • 1992
  • A policy of periodic replacement with minimal repair at failure is considered for a complex system. Under such a policy the system is replaced at periodic times. iT(i=1,2, $\ldots$), while minimal repair is performed at any intervening system failures. The cost of the j-th minimal repair to the component which fails at age t is g(C(t). $c_j$ (t)), where C(t) is the age-dependent random part, $c_j$(t) is the deterministic part which depends on the age and the number of the minimal repair to the component, and g is a positive nondecreasing continuous function. The cost of replacement is expensive when the number of failures occurring in (0. T) is greater than a threshold level. The problem of determining the optimal replacement period, $T^{\ast}$, which minimizes the total expected cost per unit time over an infinite time horizon is considered. Various special cases are considered.

  • PDF

Electric Characteristics of Tantalum Pentoxide Thin Film Formed by Thermal Oxidation (열산화법으로 형성한 탄탈륨 산화막의 전기적 특성)

  • 홍영호;박효덕;전춘배;이덕동;김봉렬
    • Journal of the Korean Institute of Telematics and Electronics A
    • /
    • v.29A no.3
    • /
    • pp.87-95
    • /
    • 1992
  • The electrical characteristics of Al/TaS12TOS15T/SiOS12T/Si metal insulator-semiconductor (MIS) capacitors were studied. Tantalum pentoxide thin films on SiOS12T/p-Si substrate have been prepared by thermal oxidation at 450-$600^{\circ}C$ of sputter deposited tantalum films. Composition and structures of the tantalum oxide films were examined by AES and XRD. From the C-V analysis, dielectric constant of TaS12TOS15T which were oxidized at 55$0^{\circ}C$ for 1h in OS12T were 18-23, the value depending on the oxidation and annealing temperature. The leakage current density was found to be about 10S0-10T-10S0-9T A/cmS02T at an applied electric field of 1 MV/cm. The dielectric breakdown strength of the tantalum oxide films annealed at 100$0^{\circ}C$ were in the range from 2.5MV/cm to 2.8 MV/cm.

  • PDF

A Study on Thermoregulation by different allowance of T-shirts (상의의 여유량 차이에 따른 체온조절반응 연구)

  • 장지혜;이소진;류정민
    • Journal of the Korean Home Economics Association
    • /
    • v.39 no.5
    • /
    • pp.39-47
    • /
    • 2001
  • The purpose of this study was to investigate two different kinds of t-shirts on thermal responses at air temperature of $23{\pm}2^{\circ}C$, relative humidity of $70{\pm}5%$ and wind velocity not more than 0.5 m/sec. Five healthy men wearing boxy type t-shirts or fitted type t-shirts, participated as the subjects. Rectal temperature, skin temperatures, heart rate, clothing microclimate and subjective sensation were measured every 2 minute during experiment(rest, walking, recovery each 20 min.) and compared between two experimental garments(boxy type and fitted type t-shirts). Rectal temperature was lower in recovery phase at wearing fitted type t-shirts. Chest skin temperature was higher at wearing fitted type t-shirts and thigh and leg skin temperature were higher at wearing boxy type t-shirts.

  • PDF

High Temperature Corrosion Properties of Heat Resistant Chrome Steels in SO2 Atmosphere (고온 이산화황 환경 내 내열 크롬강에 대한 부식특성 연구)

  • Lee, Han-sang;Jung, Jine-sung;Kim, Eui-hyun
    • Korean Journal of Metals and Materials
    • /
    • v.47 no.2
    • /
    • pp.99-106
    • /
    • 2009
  • The high temperature corrosion properties of heat resistant steels were investigated in oxidation atmosphere including sulfur dioxide. The heat resistant steels of T22, T92, T122, T347HFG and T304H were evaluated at 620, $670^{\circ}C$ for 400 hours. The corrosion rates showed a decreasing tendency while chrome contents of those steels increased from 2 mass.% to 19 mass.%. The in crease in temperature increasement has an more effect on the corrosion rates of low chrome steels than high chrome steels. The weight gains of T22, T92, T304H at $670^{\circ}C$ were 3.7, 1.65, 1.23 times compared with those at $620^{\circ}C$. The external scale formed on T22 was composed of hematite, magnetite and Fe-Cr spinel and internal layer including iron oxide mixed with sulfide. The scales formed on T92, T122, T304H consisted of an outer layer of hematite and inner layer of chrome oxide and hematite. The proportion of chrome oxide at inner layer was increased when the chrome contents in heat resistant steels were increased.

EFFECT OF SOIL mOISTURE CONDITiON ON THE GROWTH AND EVAPOTRANSPIRATION OF THE TOBACCO PLANT (토양수분의 과, 부족이 연초의 생장과 증발산량에 미치는 영향)

  • 홍순달;이윤환;김재정;조성진
    • Journal of the Korean Society of Tobacco Science
    • /
    • v.7 no.1
    • /
    • pp.15-23
    • /
    • 1985
  • Growth response and evapotranspiration of tobacco as to each soil moisture condition treated with different height of ground water table such as 30cm, 100cm, 170cm, and 230cm were investigated. The results obtained were as follows; 1. Soil water potential in the rhizosphere (25cm depth from surface) treated with ground water table (G.W.T) of 230 cm was less than -6.5 bar at 60 days after transplanting. 2. Dry weight of leaves per plant was the highest in the pot treated with 100 cm G.W.T and was the lowest in the pot treated with 230 cm G.W.T.. Leaves/Stem ratio of dry weight was the lowest in the pot treated with 230 cm G.W.T. This would show that extension of leaves as compared with elongation of stem was suppressed. .3. In the roster stress condition of 230 cm G.W.T., extension of leaves was continued until the latter growth stage, Relative growth rate of leaf area per plant of the pot with 30 cm G.W.T. was the highest through all growth period after fixation of G.W.7., but owing to lower density of leaf, the dry weight of leaves per plant was less rather than that of the pot with 170 cm G.W.T. at 64 days after transplanting. 4. The highest evapotranspiration per plant per day was shown at the 45th day after transplanting in the pots with 30cm and 100cm G.W.T. and at 60 days in the pots with 170cm and 230cm G.W.T respectively. 5. In the soil moisture conditions with 30cm and 100cm G.W.T., evapotranspiration per plant per hour was much higher in the daytime that at night as well as in clear day than in rain-cloudy day owing to loner relative humidity , but in the water stress condition with 230 cm G.W.T., that was much lower. 6. Total evapotranspiration per plant during the whole growing period of 64 days was in order of 30cm > 100 cm > 170 cm > 230 cm G.W.T.. Total evapotranspiration for 34 days after fixation of G.W.T was much higher at night than in the daytime in case of water stress conditions i.e 170cm and 230cm G.W.T. but in normal condition of the pots with 30cm and 100cm G.W.T. that was much higher in the daytime than at night. 7. Leaf water potential of the 3rd and 6th leaf from top at 64 days after transplanting was in order of 100cm > 30 cm > 170cm > 230cm G.W.T. The reason why leaf water potential in the pot with 30cm was less than that in the pot with 100cm G.W.T. would be the abnormal turgidity with low density of cell substrates by the excess water absorption in the pot with 30cm G.W.T..

  • PDF

Survival Factors among Medical Intensive Care Unit Patients with Carbapenemas-Producing Enterobacteriaceae (카바페넴분해효소 생성 장내세균속균종(CPE)이 획득된 내과계 중환자실 환자의 생존 영향 요인)

  • Choi, Ji Eun;Jeon, Mi Yang
    • Journal of Korean Biological Nursing Science
    • /
    • v.22 no.4
    • /
    • pp.249-259
    • /
    • 2020
  • Purpose: Carbapenemase-producing Enterobacteriaceae (CPE) are associated with considerable mortality. This study was aimed to identify survival factors among medical care unit patients with CPE. Methods: We conducted a retrospective cohort; data were collected from September 2017 to June 2019 through electronic medical records. The data collected were general characteristics, disease-related characteristics, severity-related characteristics, and treatment-related characteristics. Data were analyzed based on frequency, mean, standard deviation, Chi-square test, Fisher's exact test, t-test, Pearson's correlation coefficient, and Cox proportional hazard model using SPSS/WIN 21.0 program. Results: Seventy-seven patients were included (59 survivors and 18 deceased) in the study. Univariate analysis identified factors for survival associated with acquired CPE as age (t= -1.56, p= .037), simplified acute physiology 3 (SAPS3) score of admission date (t= -2.85, p= .006), Glasgow coma scale (GCS) of CPE acquisition date (t= 2.38, p= .020), artery catheter at CPE acquisition date (χ2= 4.58, p= .032), vasoconstrictor agents use at CPE acquisition date (χ2= 6.81, p= .009), platelet at CPE acquisition date (t= 2.27, p= .025), lymphocyte at CPE acquisition date (t= 2.01, p= .048), calcium at CPE acquisition date (t= 2.68, p= .009), albumin at CPE acquisition date (t= 2.29, p= .025), and creatinine at CPE acquisition date (t= 2.24, p= .028). Multivariate Cox proportional hazard model showed that GCS at CPE acquisition date (HR= 1.14, 95% CI= 1.05-1.22), lymphocyte at CPE acquisition date (HR= 1.05, 95% CI= 1.00-1.10), and creatinine at CPE acquisition date (HR= 1.25, 95% CI= 1.04-1.49) were independent survival factors among medical intensive care unit patients with CPE. Conclusion: Based on the study results, it is necessary to develop nursing interventions that can aid in the management of patients with CPE and identify their effects.

T Cells Development Is Different between Thymus from Normal and Intrauterine Growth Restricted Pig Fetus at Different Gestational Stage

  • Lin, Yan;Wang, Junjun;Wang, Xiaoqiu;Wu, Weizong;Lai, Changhua
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.26 no.3
    • /
    • pp.343-348
    • /
    • 2013
  • This experiment was conducted to evaluate the development of T cells in intrauterine growth retarded (IUGR) piglets at different gestational stages, and tentatively explore the relationship between T cells development and the Notch signaling pathway. A total of 18 crossbred (Landrace${\times}$Large white) primiparous sows were mated at similar weights and estruses and euthanized at d 60, 90 and 110 of gestation with six replicates for each time point. One IUGR and one normal fetus were picked from each litter. The T-cell subsets, mRNA expression of Delta-like1, Delta-like4, Jagged1, and Notch2 genes in the thymus were investigated. Compared to normal piglets, $CD3^+CD4^-CD8^+$ cells in IUGR fetuses at d 90 was 0.13% lower (p<0.05). At d 110 of gestation $CD8^+$ T cells in IUGR fetuses was 0.19% lower (p<0.05). The percentage of $CD8^+$ T cells was 3.14% lower (p<0.05) of the total T cells in IUGR pigs at d 60. The abundance of Notch2 and Delta-like4 mRNA at d 110 was 20.93% higher and 0.77% (p<0.05) lower, and Delta-like1 mRNA at d 90 was 0.19% (p<0.05) higher compared to normal pigs. These results suggested that normal fetuses had a greater proportion of T-cell subsets at earlier gestation periods, and the Notch signaling pathway was likely partially responsible for these differences to some degree.

Analysis of the Characteristics of NPS Runoff and Application of L-THIA model at Upper Daecheong Reservoir (대청호 상류 유역의 비점오염원 유출특성 분석 및 L-THIA 모형 적용성 평가)

  • Shin, Min-Hwan;Lee, Jae-An;Cheon, Se-Uk;Lee, Yeoul-Jae;Lim, Kyoung-Jae;Choi, Joong-Dae
    • Journal of The Korean Society of Agricultural Engineers
    • /
    • v.52 no.1
    • /
    • pp.1-11
    • /
    • 2010
  • Generation and transportation of runoff and pollutant loads within watershed generated eutrophication at Daecheong reservoir. To improve water quality at Daecheong reservoir, the best management practices should be developed and applied at upper watersheds for water quality improvement at downstream areas. In this study, two small watersheds of upper Daecheong reservoir were selected. The Long-Term Hydrologic Impact Assessment (L-THIA) model has been widely used for the estimation of the direct runoff worldwide. To apply the L-THIA ArcView GIS model was evaluated for direct runoff and water quality estimation at small watershed. And the Web-based Hydrograph Analysis Tool (WHAT) was used for direct runoff separating from total flow. As a result, the $R^2$ (Coefficient of determination) value and Nash-Sutcliffe coefficient value for direct runoff comparison at An-nae watershed were 0.81 and 0.71, respectively. And the $R^2$ value and Nash-Sutcliffe coefficient value at Wol-oe were 0.95 and 0.93. The $R^2$ value of BOD, TOC, T-N and T-P at An-nae watershed were BOD 0.94, TOC 0.81, T-N 0.94 and T-P 0.89. And the $R^2$ value of BOD, TOC, T-N and T-P at Wol-oe watershed were BOD 0.80, TOC 0.93, T-N 0.86 and T-P 0.65. The result that estimated pollutant loadings using the L-THIA ArcView GIS model reflected well the measured pollutant loadings except for T-P in Wol-oe watershed. With L-THIA ArcView GIS model, the direct runoff and non-point pollutant (NPS) loadings in the watershed could be analyzed through simple input data such as daily rainfall, land uses, and hydrologic soil group.

Effect of Ultramarathon on the Anterior Pituitary and Thyroid Hormones (울트라마라톤이 뇌하수체 전엽 및 갑상선 호르몬에 미치는 영향)

  • Shin, Kyung-A;Kim, Young-Joo
    • The Korean journal of sports medicine
    • /
    • v.36 no.4
    • /
    • pp.214-220
    • /
    • 2018
  • Purpose: The purpose of this research is to study changes in pituitary hormone in anterior lobe and thyroid hormone before, after, and during recovery time in severe 100 km ultramarathon. Methods: Healthy middle-aged runners (age, $52.0{\pm}4.8$ years) participated in the test. Grade exercise test is done, and then blood is taken from those participants before and after completing 100 km ultramarathon at the intervals of 24 hours (1 day), 72 hours (3 days), and 120 hours (5 days) to analyze their luteinizing hormone (LH), follicle-stimulating hormone (FSH), thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), and free thyroxine (Free T4). Results: For LH, it decreased more significantly at 100 km than pre-race. However, after 1 day result increased more than that of 100 km. At 3 days, it was significantly higher than pre-race and 100 km, recovering at 5 days. In terms of FSH, it decreased at 100 km, 1 day, and 3 days more than pre-race but recovered at 5 days. TSH was higher at 1 day and 5 days compared to pre-race. T3 was only higher at 100 km than pre-race. T4 was higher till 5 days at 100 km than pre-race. Free T4 increased more significantly at 100 km than pre-race. Conclusion: In terms of severe long distance running, LH and FSH which belong to hormone from anterior lobe as well as T3, T4, and Free T4 which belong to thyroid hormone showed their variation within the standard range. However, TSH showed abnormal increase from enhanced concentration of blood after marathon becoming hyper-activation even during the recovery period.