• Title/Summary/Keyword: primary phase

Search Result 1,058, Processing Time 0.029 seconds

Metabolic Imbalance between Glycolysis and Mitochondrial Respiration Induced by Low Temperature in Rice Plants (벼 냉해의 초기 기작으로서 생체막과 세포질 사이의 대사 불균형)

  • Lee, Keun-Pyo;Boo, Yong-Chool;Jung, Jin
    • Applied Biological Chemistry
    • /
    • v.43 no.4
    • /
    • pp.236-240
    • /
    • 2000
  • Correlations between mitochondrial respiration, glycolysis activity and overall growth activity of rice (Oryza sativa: cv. Dasan) seedlings during low temperature exposure were studied in order to provide insights into the underlying mechanism for the primary phase of chilling injury in plants. Among cellular membranes involved in energy metabolism, only the mitochondrial inner membrane showed not only physical phase transition at ca. $13^{\circ}C$, as monitored by ESR spin label, but also functional phase transition at the same temperature, as assessed by cytochrome c oxidase activity. The main regulatory enzyme of glycolysis, phosphofructokinase, in situ did not suffer phase transition of its activity at least in the $4{\sim}27^{\circ}C$ range. Low temperature caused a significant accumulation of glucose 6-phosphate (G6P) and fructose 6-phosphate (F6P), which disappeared almost completely on rewarming of the seedlings. Temperature profiles of the steady state levels of G6P and F6P revealed the inflection point appearing at around phase transition temperature of the mitochondrial membrane. The results conform to our previous proposition on the mechanism for the early stage events of chilling injury that the accumulation of glycolytic metabolites in cells due to metabolic imbalance at low temperature gives rise to an excess supply of electrons during rewarming period, which, in turn, results in overproduction of active oxygen in mitochondria.

  • PDF

Efficacy and Safety of Neurokinin-1 Receptor Antagonists for Prevention of Chemotherapy-Induced Nausea and Vomiting: Systematic Review and Meta-analysis of Randomized Controlled Trials

  • Yuan, Dong-Mei;Li, Qian;Zhang, Qin;Xiao, Xin-Wu;Yao, Yan-Wen;Zhang, Yan;Lv, Yan-Ling;Liu, Hong-Bin;Lv, Tang-Feng;Song, Yong
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.17 no.4
    • /
    • pp.1661-1675
    • /
    • 2016
  • Objectives: Can addition of neurokinin-1 receptor antagonists (NK1-RAs) be considered as an ideal strategy for the prevention of chemotherapy-induced nausea and vomiting (CINV)? Researchers differ on this question. Materials and Methods: Electronic databases were searched for randomized control trials (RCTs) that evaluated the effectiveness and safety of NK1-RAs in preventing CINV. The primary end point was complete response (CR) in the acute, delayed, and overall phases after chemotherapy. Subgroup analyses evaluated the types of NK1-RAs, routines of administration, types of malignancies, regimens used in combination with NK1-RAs, and age of patients included in the studies. The incidences of different types of adverse events were also extracted to estimate the safety of NK1-RAs. Results: A total of 38 RCTs involving 13,923 patients were identified. The CR rate of patients receiving NK-RAs was significantly higher than patients in the control groups during overall phase (70.8% vs 56.0%, P<0.001), acute phase (85.1% vs 79.6%, P<0.001), and delayed phase (71.4% vs 58.2%, P<0.001). There were three studies including patients of children or adolescents, the CR rate was also significantly higher in the treatment group (overall phase: OR=2.807, P<0.001; acute phase: OR=2.863, P =0.012; delayed phase: OR=2.417, P<0.001). For all the other outcomes, patients in the NK1-RAs groups showed improvements compared to the control groups (incidence of nausea: 45.2% vs 45.9%, P<0.001; occurrence of vomiting: 22.6% vs 38.9%, P<0.001; usage of rescue drugs: 23.5% vs 34.1%, P<0.001). The pooled side effects from NK1-RAs did not significantly differ from previous reports and the toxicity rates in patients less than eighteen years old also did not diff between the two groups (P=0.497). However, we found that constipation and insomnia were more common in the patients of control groups, whereas diarrhea and hiccups were more frequently detected in patients receiving NK1-RAs. Conclusions: NK1-RAs improved the CR rate of CINV. They are effective for both adults and children. The use of NK1-RAs might be associated with the appearance of diarrhea and hiccups, while decreasing the possibility of constipation and insomnia.

Enhanced Sensitivity and Long-Term G2/M Arrest in Adriamycin-treated DNA-PK-null Cells are Unrelated to DNA Repair Defects (DNA-PK-null 세포주의 adriamycin 처리에 의한 G2/M 세포주기 변화)

  • Kim, Chung-Hee;Kim, Jong-Soo;Van Cuong, Dang;Kim, Na-Ri;Kim, Eui-Yong;Han, Jin
    • Journal of Life Science
    • /
    • v.13 no.3
    • /
    • pp.241-247
    • /
    • 2003
  • While the DNA-protein kinase (DNA-PK) complex, comprised of DNA-PKcs and Ku80, is primary involved in the repair of DNA double-strand breaks, it is also believed to participate in additional cellular processes. Here, treatment of embryo fibroblasts (MEFs) derived from either wild-type (Wt) or DNA-PKcs-null (DNA-$PKcs^{-/-}$) mice with various stress inducing agents revealed that adriamycin was markedly more cytotoxic for $Ku80^{-/-}MEFs$ and led to their long-term accumulation in the $G_2$/M phase. This differential response was not due to differences in DNA repair, since adrimycin-triggered DNA damage was repaired with comparable efficiency in both Wt and $Ku80^{-/-}MEFs$, but was associated with differences in the expression of important cell cycle regulatory genes. Our results support the notion that Ku80-mediated cytoprotection and $G_2$/M-progression are not only dependent on the cell's DNA repair but also may reflect Ku80's influence on additional cellular processes such as gene expression.

Study on Fluid Inclusions in Fluorite from the Sinpo Mine (신포광산(新浦鑛山) 형석(螢石)의 유체포유물(流體包有物에)에 관(關)한 연구(硏究))

  • Lee, Choon Woo
    • Economic and Environmental Geology
    • /
    • v.2 no.4
    • /
    • pp.1-21
    • /
    • 1969
  • The Sin po fluorite deposit is of a fissure vein type which strikes $N75^{\circ}E$, dips $80^{\circ}SE$, and is embedded in the pre-Cambrian crystalline schist. The vein is 1 meter in average in thickness, about 800 meters in length and nearly 400 meters in depth. Narrow veins of crustified fluorites and agatic quartz are discontinuously embedded in the quartz gangue. Two-phase fluid inclusions, which are available for the homogenization method by using the Heating Stage Microscope 350, are found in the fluorite crystals. Most of the fluid inclusions are primary in origin and mainly composed of liquid phase associated with minor gas phase. They are tetrahedral, rounded-tubular, wedge shaped, rectangulartrapezoid, and irregular in shape. The maximum diameter of inclusions is 0.5mm and the minimum, 0.03mm, ranging from 0.2mm to 0.08mm in an average. The homogenization temperatures obtained from the test are $135-147^{\circ}C$, $125-138^{\circ}C$, $121-137^{\circ}C$, $116-133^{\circ}C$ and $106-128^{\circ}C$ in greenish, bluish, violet, light grayish blue, colorless and pinkish fluorites respectively. The range of formation temperatures of fluorites is $106-147^{\circ}C$. Therefore, the fluorite deposit of Sinpo Mine is considered to be of low temperature hydrothermal origin. The isothermal lines were drawn on the longitudinal section of the vein from the data of homogenization test. According to the results, the central and lower parts of the ore shoot in the west ore body show the higher temperatures of $130-138^{\circ}C$ and the peripheral and upper parts of it show the lower temperatures of $108-128^{\circ}C$. It seems that the isothermal trend roughly coinside with the pitch of the ore shoot.

  • PDF

Study on validating proper System Requirements by using Cost Estimations Methodology (비용추정방법을 활용한 시스템요구사항 적정성 확인방안 연구)

  • Choi, Sung Kyu;Choi, Eun Ha
    • Convergence Security Journal
    • /
    • v.13 no.5
    • /
    • pp.97-105
    • /
    • 2013
  • It is very important the government project should be supported by enough budget for proceeding. The insufficient budget by poor budget estimating uesd to bring about discontinuing for the project. This is originally caused by inaccuracy for cost estimating about system and evaluating for system requirements on the projet initial phase. The system requirements is technical requirements that converted the user needs and is needs for communicating between stakeholder and developer and manufacturer. Also the system requirements is the primary factor to make the project cost. The cost estimating is not easy due to complication of cost factors and an aberration between cost estimating and actual cost. Specially, on the project initial phase, shortage of detail information for project make more difficult to do cost estimating. This study proposes the architecture for validating proper system requirements by using cost estimations methodology on the project initial phase and shows the computer tool for simulating the proposed architecture.

A New Replacement Method of Distribution Transformers without Outage using the Phase Converter (위상변환장치를 이용한 새로운 배전변압기 무정전 교체방법)

  • Shin, Dong-Yeol;Kim, Suk-Cheol;Yoon, Gi-Gab;Cha, Han-Ju
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.21 no.10
    • /
    • pp.166-175
    • /
    • 2007
  • Nowadays, the power quality issue becomes very important in the electric distribution system. Especially, when a distribution transformer is replaced, the customers who are supplied electricity from the transformer feel inconvenience due to electric outage. Therefore, an advanced method for the distribution transformer replacement without outage is strongly required. The conventional method is the primary-secondary high voltage bypass method according to the transformer utilization factor and the field condition. But it is inconvenient and has some problems such as breakdown and security troubles of the workers according to the unauthorized and temporary work. Therefore, the new scheme for the replacement with uninterruptable power supply is demanded. This paper proposes the new replacement method using the phase converter. The proposed method can reduces the process of replacement work and also ensures worker's safety. Therefore, the method is reasonable in comparison with the conventional method. The proposed method is able to contribute the national economy growth and elevate the convenience of national life by uninterruptable power supply.

An improvement of cycloconverter output using phase shifting filter (상천이 필터를 이용한 싸이클로컨버터 출력의 개선)

  • Kim, Jong-Su;Seo, Dong-Hoan;Kim, Jeong-Woo;Kim, Sung-Hwan
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.37 no.1
    • /
    • pp.121-126
    • /
    • 2013
  • Cycloconverter used as a power conversion device in the speed and torque control system of AC machines has the advantage of a simple control and a large torque at low speed. In addition, because a rectifier, a DC link, and an inverter are not installed, this system is simple and suitable for large power system. If a power conversion device, which is currently used as a propulsion motor of large vessel, is changed into cycloconverter, the system is simplified and then the installation costs can be significantly reduced. However, conventional cycloconverter has the increased harmonics because the power loss is large and the waveform of output voltage is distorted, due to the high-speed switching of power semiconductor devices. In order to improve these shortcomings, this paper describes a phase shifting filter which is composed of two inputs with different phases in the primary side and one output in the secondary one. As the voltage waveforms with two different phases are added and transformed into the secondary side, these outputs are close to sinusoidal waves. Thereby the voltage waveforms, which are applied to the propulsion motors, are improved and total harmonic distortions (THDs) are significantly reduced.

Development of 8kW ZVZCS Full Bridge DC-DC Converter by Parallel Operation (병렬제어를 적용한 8kW급 영전압/영전류 풀 브릿지 DC-DC 컨버터 개발)

  • Rho, Min-Sik
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.12 no.5
    • /
    • pp.400-408
    • /
    • 2007
  • In this paper, development of the 8kW parallel module converter is presented. For a effective configuration of FB-PWM converter, this paper proposes 4-parallel operation of 2 kw-module. FB converter of 2-kW module is controlled by phase shut PWM and in order to achieve ZVZCS, the simple auxiliary circuit is applied in secondary side. In order to achieve ZCS, control logic for auxiliary circuit operation is designed to reset the primary current during free-wheeling period. For output current sharing of 4-modules, the charge control is employed. The charge control logic is designed with phase shift PWM logic. Voltage controller is implemented by using DSP(TMS320LF2406) with A/D conversion data of the output current and voltage of each module. The developed converter is installed in PCU(Power Conditioning Unit) for HSG(High Speed Generator) in a vehicle and health monitoring system is implemented for vehicle operation test. Finally, performance of the developed converter is proved under practical operation of HSG.

Understanding the Effect on Hydrogen Evolution Reaction in Alkaline Medium of Thickness of Physical Vapor Deposited Al-Ni Electrodes (Physical Vapor Deposition 방법으로 제조된 Al-Ni 전극의 두께가 알칼라인 수전해 수소발생반응에 미치는 영향 연구)

  • HAN, WON-BI;CHO, HYUN-SEOK;CHO, WON-CHUL;KIM, CHANG-HEE
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.28 no.6
    • /
    • pp.610-617
    • /
    • 2017
  • This paper presents a study of the effect of thickness of porous Al-Ni electrodes, on the Hydrogen Evolution Reaction (HER) in alkaline media. As varying deposition time at 300 W DC sputtering power, the thickness of the Al-Ni electrodes was controlled from 1 to $20{\mu}m$. The heat treatment was carried out in $610^{\circ}C$, followed by selective leaching of the Al-rich phase. XRD studies confirmed the presence of $Al_3Ni_2$ intermetallic compounds after the heat treatment, indicating the diffusion of Ni from the Ni-rich phase to Al-rich phase. The porous structure of the Al-Ni electrodes after the selective leaching of Al was also confirmed in SEM-EDS analysis. The double layer capacitance ($C_{dl}$) and roughness factor ($R_f$) of the electrodes were increased for the thicker Al-Ni electrodes. As opposed to the general results in above, there were no further improvements of the HER activity in the case of the electrode thickness above $10{\mu}m$. This result may indicate that the $R_f$ is not the primary factor for the HER activity in alkaline media.

Selective Harmonic Elimination in Multi-level Inverters with Series-Connected Transformers with Equal Power Ratings

  • Moussa, Mona Fouad;Dessouky, Yasser Gaber
    • Journal of Power Electronics
    • /
    • v.16 no.2
    • /
    • pp.464-472
    • /
    • 2016
  • This study applies the selective harmonic elimination (SHE) technique to design and operate a regulated AC/DC/AC power supply suitable for maritime military applications and underground trains. The input is a single 50/60 Hz AC voltage, and the output is a 400 Hz regulated voltage. The switching angles for a multi-level inverter and transformer turns ratio are determined to operate with special connected transformers with equal power ratings and produce an almost sinusoidal current. As a result of its capability of directly controlling harmonics, the SHE technique is applicable to apparatus with congenital immunity to specific harmonics, such as series-connected transformers, which are specially designed to equally share the total load power. In the present work, a single-phase 50/60 Hz input source is rectified via a semi-controlled bridge rectifier to control DC voltage levels and thereby regulate the output load voltage at a constant level. The DC-rectified voltage then supplies six single-phase quazi-square H-bridge inverters, each of which supplies the primary of a single-phase transformer. The secondaries of the six transformers are connected in series. Through off-line calculation, the switching angles of the six inverters and the turns ratios of the six transformers are designed to ensure equal power distribution for the transformers. The SHE technique is also employed to eliminate the higher-order harmonics of the output voltage. A digital implementation is carried out to determine the switching angles. Theoretical results are demonstrated, and a scaled-down experimental 600 VA prototype is built to verify the validity of the proposed system.