• 제목/요약/키워드: cell cycles

검색결과 528건 처리시간 0.023초

Effects of three-area laser-assisted zona thinning in 8-cell human embryos on pregnancy outcomes in vitro fertilization

  • Jeong, Ju-Eun;Joo, Bo-Sun;Kim, Chang-Woon;Kim, Hwi-Gon;Joo, Jong-Kil;Lee, Kyu-Sup
    • Clinical and Experimental Reproductive Medicine
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    • 제45권1호
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    • pp.25-30
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    • 2018
  • Objective: This study conducted a preliminary examination of the effects of three-area laser-assisted zona thinning (LAZT) during the cleavage stage of embryo development on the hatching process in human in vitro fertilization-embryo transfer (IVF-ET) with subjects of advanced female age or frozen-thawed (FT) embryos. Methods: Eight-cell stage embryos were treated with LAZT in three areas of the zona pellucida at $120^{\circ}$ intervals. The control group was embryos without LAZT. Of the 72 consecutive fresh cycles and the 28 FT embryo transfer cycles, the patients in 55 fresh cycles and 17 FT cycles declined LAZT, and those cycles were defined as the control group. Results: In the fresh cycles, the pregnancy rates were similar in the LAZT and control groups. However, in the FT cycles, the pregnancy rate was significantly higher in the LAZT group than in the control group (45.5% in the LAZT group vs. 23.5% in the control group, p< 0.05). Conclusion: These results show that multi-area LAZT resulted in significantly improved pregnancy outcomes in human 8-cell embryos compared to controls.

Investigation of Endurance Degradation in a CTF NOR Array Using Charge Pumping Methods

  • An, Ho-Myoung;Kim, Byungcheul
    • Transactions on Electrical and Electronic Materials
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    • 제17권1호
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    • pp.25-28
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    • 2016
  • We investigate the effect of interface states on the endurance of a charge trap flash (CTF) NOR array using charge pumping methods. The endurance test was completed from one cell selected randomly from 128 bit cells, where the memory window value after 102 program/erase (P/E) cycles decreased slightly from 2.2 V to 1.7 V. However, the memory window closure abruptly accelerated after 103 P/E cycles or more (i.e. 0.97 V or 0.7 V) due to a degraded programming speed. On the other hand, the interface trap density (Nit) gradually increased from 3.13×1011 cm−2 for the initial state to 4×1012 cm−2 for 102 P/E cycles. Over 103 P/E cycles, the Nit increased dramatically from 5.51×1012 cm−2 for 103 P/E cycles to 5.79×1012 cm−2 for 104 P/E cycles due to tunnel oxide damages. These results show good correlation between the interface traps and endurance degradation of CTF devices in actual flash cell arrays.

6개월간 산삼약침요법을 시행 받은 ⅢB기 편평세포폐암 환자에 대한 증례보고 (A Case Report for Stage ⅢB Squamous Cell Lung Carcinoma Patient Treated with Cultured Wild Ginseng Pharmacopuncture Therapy)

  • 박봉기;조종관;권기록;유화승
    • 대한약침학회지
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    • 제10권3호
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    • pp.143-147
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    • 2007
  • Objective To derive further studies evaluating the effectiveness of Cultured Wild Ginseng Pharmacopuncture (CWGP) Therapy on squamous cell carcinoma as a first line. Methods Three cycles (4 weeks/cycle) of CWGP were administered as a dosage of 10 ml per day. Patient was diagnosed with stage IIIB squamous cell carcinoma and refused all therapy of conventional medicine because of old age and cardiac invasion of tumor. Intensive treatment of CWGP for 3 cycles was done on the patient. Computed Topography (CT) was performed to evaluate the therapeutic efficacy. Results After the intravenous infusion of 2 cycles of CWGP, chest CT revealed the mass size and pleural invasion sustained stable disease. After the point injection of 1 cycle of CWGP, chest CT revealed progressive disease. The disease free survival rate was 1 month. Conclusion This case may provide us the possibility that CWGP offers potential benefits for patients with squamous cell lung carcinoma. But this is a single case study and further case-series research should be compensated.

Optimal Timing of Radiotherapy with Alternating/Sequential Radio-Chemotherapy for Limited-stage Small Cell Lung Cancer

  • Wang, Li-Jie;Liu, Xiu-Ju;Guan, Yan;Zhang, Chu-Feng;Wang, Peng;Li, Yan;Guo, Qi-Sen
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권14호
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    • pp.5697-5699
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    • 2014
  • Objective: To investigate the optimal timing of radiotherapy with alternating/sequential radio-chemotherapy for limited-stage small cell lung cancer (LS-SCLC). Methods: 91 patients with LS-SCLC were retrospectively analyzed and divided into two groups according to the number of chemotherapy cycles before radiotherapy. If the patient received radiotherapy after 3 cycles or fewer cycles of chemotherapy, classification was into the early group, if not, into the late group. All patients received 6 cycles of standard chemotherapy (EP/EC) and conventional radiotherapy (56 gy~ 60 gy/28 f ~30 f). Results: The response rate (RR) of the early and late groups were 85.7% and 81.6%, respectively, with no significant difference (p>0.05). In contrast, the progression-free survival (PFS) in the early group was better than that in the late group (11.8 months vs 9.86 months), and the difference was significant (p<0.05). There was no significant difference between two groups in adverse reactions, which gastrointestinal irritation and bone marrow suppression being the most common (p>0.05). Conclusions: Radiotherapy after 3 cycles or fewer cycles of chemotherapy does not bring significant benefits for RR of patients with LS-SCLC, but it could significantly prolong their PFS without increase in adverse reactions.

Study of Flooding Prevention on Cathode Gas Diffusion Layer for Dynamic Load Fuel Cell

  • Choi, Dong-Won;You, Jin-Kwang;Rokhman, Fatkhur;Bakhtiar, Agung;Choi, Kwang-Hwan
    • 한국태양에너지학회:학술대회논문집
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    • 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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    • pp.270-273
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    • 2011
  • Water management is important in proton exchange membrane fuel cell because the water balance has a significant impact on the overall fuel cell system performance. In fuel cell vehicle, the vehicle's power demand is dynamic; therefore, the dynamic water management system is required. This present study proposes a method to control the humidity of the input air in cathode side of the fuel cell vehicle. The simulation using several driving cycles shows the proposed air humidification control obtains a relatively good result. The liquid saturation level is seen constant at the target level although still there are small deviations at driving cycles which having averagely high power demands.

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고분자전해질 연료전지 내구성 향상을 위한 시동 기술 개발에 관한 연구 (Development of a Durable Startup Procedure for PEMFCs)

  • 김재홍;조유연;장종현;김형준;임태훈;오인환;조은애
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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    • pp.288-294
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    • 2009
  • Various polymer electrolyte membrane fuel cell (PEMFC) startup procedures were tested to explore possible techniques for reducing performance decay and improving durability during repeated startup-shutdown cycles. The effects of applying a dummy load, which prevents cell reversal by consuming the air at the cathode, on the degradation of a membrane electrode assembly (MEA) were investigated via single cell experiments. The electrochemical results showed that application of a dummy load during the startup procedure significantly reduced the performance decay, the decrease in the electrochemically active surface area (EAS), and the increase in the charge transfer resistance ($R_{ct}$), which resulted in a dramatic improvement in durability. After 1200 startup-shutdown cycles, post-mortem analyses were carried out to investigate the degradation mechanisms via various physicochemical methods including FESEM, an on-line $CO_2$ analysis, EPMA, XRD, FETEM, SAED, FTIR. After 1200 startup-shutdown cycles, severe Pt particle sintering/agglomeration/dissolution and carbon corrosion were observed at the cathode catalyst layer when starting up a PEMFC without a dummy load, which significantly contributed to a loss of Pt surface area, and thus to cell performance degradation. However, applying a dummy load during the startup procedure remarkably mitigated such severe degradations, and should be used to increase the durability of MEAs in PEMFCs. Our results suggest that starting up PEMFCs while applying a dummy load is an effective method for mitigating performance degradation caused by reverse current under a repetition of unprotected startup cycles.

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원통형 고체산화물연료전지용 다공성 NI-YSZ 연료극의 Redox 사이클 특성 (Characterization of Redox Cycles of NI-YSZ Porous Anode Support for Tubular SOFCs)

  • 허연혁;박광연;이종원;이승복;임탁형;박석주;송락현;신동열
    • 한국수소및신에너지학회논문집
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    • 제21권6호
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    • pp.526-532
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    • 2010
  • The anode may inevitably undergo a number of reduction.oxidation (redox) cycles during solid oxide fuel cells (SOFCs) operation. The re-oxidation of Ni to NiO causes significant mechanical stress to be developed across the anode, which may destroy the integrity of the whole cell. In this study, the redox behavior of Ni-YSZ composite was examined at $800^{\circ}C$ using various characterization techniques.

The end effector of circadian heart rate variation: the sinoatrial node pacemaker cell

  • Yaniv, Yael;Lakatta, Edward G.
    • BMB Reports
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    • 제48권12호
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    • pp.677-684
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    • 2015
  • Cardiovascular function is regulated by the rhythmicity of circadian, infradian and ultradian clocks. Specific time scales of different cell types drive their functions: circadian gene regulation at hours scale, activation-inactivation cycles of ion channels at millisecond scales, the heart's beating rate at hundreds of millisecond scales, and low frequency autonomic signaling at cycles of tens of seconds. Heart rate and rhythm are modulated by a hierarchical clock system: autonomic signaling from the brain releases neurotransmitters from the vagus and sympathetic nerves to the heart's pacemaker cells and activate receptors on the cell. These receptors activating ultradian clock functions embedded within pacemaker cells include sarcoplasmic reticulum rhythmic spontaneous Ca2+ cycling, rhythmic ion channel current activation and inactivation, and rhythmic oscillatory mitochondria ATP production. Here we summarize the evidence that intrinsic pacemaker cell mechanisms are the end effector of the hierarchical brain-heart circadian clock system.

유제한성 병기의 소세포 폐암에서 3주 간격으로 시행된 irinotecan과 cisplatin을 이용한 과다분할 방사선 동시 요법 (Phase II Study of Induction Irinotecan + Cisplatin Chemotherapy Followed by Concurrent Irinotecan + Cisplatin Plus Twice-Daily Thoracic Radiotherapy)

  • 이정은;박희선;정성수;김주옥;조문준;김진환;이충식;김선영
    • Tuberculosis and Respiratory Diseases
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    • 제63권2호
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    • pp.154-164
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    • 2007
  • 배경: Irinotecan hydrochloride는 topoisomerase I inhibitor로서 소세포 폐암에 효과적인 약제로 알려져 있다. Irinotecan은 cisplatin과 더불어 방사선감작물질로 작용하기도 한다. 본 연구는 이전에 치료받은 경험이 없는 제한성 병기의 소세포 폐암 환자에서 irinotecan과 cisplatin(IP)의 방사선 동시화학요법의 효과를 평가하기 위하여 시행되었다. 방법: 2002년 12월부터 2004년 11월까지 충남대학교 병원에서 새로이 제한성 병기의 소세포 폐암으로 진단된 24명의 환자들을 대상으로 하였다. Irinotecan $60mg/m^2$을 제 1일과 제 8일째 투여하였고 cisplatin $60mg/m^2$을 제 1일째 투여하였으며 매 3주 간격으로 시행되었다. 제 3차 항암화학요법을 시작하는 날과 동시에 과다 분할방사선 치료(twice-daily thoracic irradiation; 45 Gy total)을 시작하였다. 예방적 전 뇌 방사선 조사(Prophylactic cranial irradiation)가 방사선 동시화학요법이 끝난 후 완전반응(complete response)을 나타낸 환자에서 시행되었다. 제 2차 항암요법과 제 6차 항암요법이 끝난 후에 흉부 전산화 단층촬영과 기관지경 등을 통한 병기의 재평가가 이루어졌다. 결과: 병기의 재평가는 19명의 환자에게 이루어졌다. 중앙 추적관찰기간은 12.5개월이고 전체 99회의 항암치료가 시행되었다. 평균 한 환자당 5.2회의 항암치료가 시행되었다. 실제 용량강도는 cisplatin $19.6mg/m^2$/week과 irinotecan $38.2mg/m^2$/week이었다. 9명의 환자가 완전반응을 보였고 10명의 환자가 부분반응(partial response)을 보여서 전체 반응률은 95%였다. 3에서 4도의 혈액학적 독성은 백혈구 감소증(35% of cycles), 빈혈(7% of cycles), 혈소판 감소증(7% of cycles) 등으로 나타났다. 3에서 4도의 비 혈액학적 독성은 설사(5% of cycles)였다. 3에서 4도의 방사선 식도염(10% of patients)을 제외하고는 과다 분할 방사선 치료를 이용한 방사선 동시 화학요법의 기존의 방법과 독성 면에서는 큰 차이가 없었다. 치료와 관련된 사망은 관찰되지 않았다. 평가가 가능한 환자들에서 1년 생존율과 2년 생존율은 각각 89% (16/18)와 47% (9/18)였다. 결론: 3주 간격으로 시행된 irinotecan과 cisplatin을 이용한 과다분할 방사선 동시 요법은 제한성 병기의 소세포 폐암 환자에서 부작용은 높지 않으면서 효과적인 치료법으로 고려될 수 있을 것이다.

동결/해동 열사이클이 PEFC의 GDL/MEA에 미치는 영향 (Freeze/Thaw cycle effects on GDLs and MEAs of PEFC)

  • 임남윤;박구곤;박진수;윤영기;이원용;임태원;김창수
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2006년도 춘계학술대회
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    • pp.96-98
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    • 2006
  • Proper water management is vital to achieve high performance and durability of PEFC (Polymer Electrolyte Fuel Cell). The effects of the residual water from PEFC after purge in shut-down processes on GDL/MEAs were investigated with freeze/thaw cycles Freeze/thaw cycle tests were conducted with single cells which were designed from transparent acryl plates. Single cells which contain several amount of residual water were cycles from $80^{\circ}C$ to $-28^{\circ}C$. The resistance changes of the single cells which have various amount of residual water were evaluated by ac-impedance analysis with 24 times of freeze/thaw cycles. Also, after the freeze/thaw cycles, the property changes were characterized by visual methods such as SEM, EPMA. Though it was difficult to observe noticeable property changes in the visual characterizations, the resistance of cells dramatically increased with the amount of remained water.

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