• 제목/요약/키워드: half cell

검색결과 830건 처리시간 0.028초

HPV Prevalence and Cervical Intraepithelial Neoplasia among HIV-infected Women in Yunnan Province, China: A Pilot Study

  • Zhang, Hong-Yun;Tiggelaar, Sarah M.;Sahasrabuddhe, Vikrant V.;Smith, Jennifer S.;Jiang, Cheng-Qin;Mei, Run-Bo;Wang, Xian-Guo;Li, Zu-An;Qiao, You-Lin
    • Asian Pacific Journal of Cancer Prevention
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    • 제13권1호
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    • pp.91-96
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    • 2012
  • Objectives: To determine the prevalence of HPV and cervical neoplasia among HIV-infected women in southwestern China. Methods: Cervical cytology, HPV detection by Hybrid Capture-$2^{TM}$ assay, and diagnostic colposcopy were followed by cervical biopsy if indicated. Logistic regression analysis was used to analyze associations between HPV co-infection and cervical intraepithelial neoplasia (CIN), and HIV-related clinical and laboratory parameters. Results: Colposcopic-histopathologically proven CIN2+ lesions were present in 7/83 (8.4%) HIV-infected women. Nearly half (41/83, 43%) were co-infected with carcinogenic HPV genotypes. HPV co-infection was higher in women with colposcopic-histopathologically proven CIN2+ lesions than women with $cells/{\mu}L$ had higher CIN2+ prevalence after adjusting for current ART status and age (adjusted OR: 6.3, 95% CI: 1.1, 36.5). Conclusions: HIV/AIDS care and treatment programs should integrate effective cervical cancer prevention services to mitigate the risk of invasive cervical cancer among HIV-infected women in China.

Clinico-pathological Features of Gynecological Malignancies in a Tertiary Care Hospital in Eastern India: Importance of Strengthening Primary Health Care in Prevention and Early Detection

  • Sarkar, Madhutandra;Konar, Hiralal;Raut, Deepak
    • Asian Pacific Journal of Cancer Prevention
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    • 제14권6호
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    • pp.3541-3547
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    • 2013
  • Background: This cross-sectional observational study was undertaken to establish clinico-pathological characteristics of patients with gynecological malignancies, focusing mainly on symptoms, histological type and stage of the disease at presentation, in a tertiary care setting in Eastern India. Materials and Methods: In the gynecology out-patient clinic of a tertiary care hospital in Kolkata, India, the patients with suggestive symptoms of gynecological malignancies were screened. Their diagnoses were confirmed by histopathology. One hundred thirteen patients with histopathologically confirmed gynecological malignancies were interviewed. Results: The most frequently reported symptoms by the patients with histopathologically confirmed gynecological malignancies were excessive, offensive with or without blood stained vaginal discharge (69.0%), irregular, heavy or prolonged vaginal bleeding (36.3%) and postmenopausal bleeding (31.9%). The majority of the patients (61.0%) had squamous cell carcinoma on histopathological examination, followed by adenocarcinoma (30.1%). Nearly half of the patients (48.7%) were suffering from the Federation Internationale des Gynaecologistes et Obstetristes (FIGO) stage III, followed by stage II (40.7%) malignancy. Conclusions: This study highlights that most of the patients with gynecological malignancies present late at an appropriate health care facility. Ovarian cancer may often have non-specific or misleading symptomatic presentation, whereas cervical cancer often presents with some specific symptoms. These observations point to the need for increasing awareness about gynecological malignancies in the community and providing easily accessible adequate facilities for early detection and treatment of the disease by optimal use of available resources, i.e. strengthening the primary health care system.

Ground-based model study for spaceflight experiments under microgravity environments on thermo-solutal convection during physical vapor transport of mercurous chloride

  • Choi, Jeong-Gil;Lee, Kyong-Hwan;Kim, Geug-Tae
    • 한국결정성장학회지
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    • 제17권6호
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    • pp.256-263
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    • 2007
  • For $P_B=50Torr,\;P_T=5401Torr,\;T_S=450^{\circ}C,\;{\Delta}T=20K$, Ar=5, Pr=3.34, Le=0.01, Pe=4.16, Cv=1.05, adiabatic and linear thermal profiles at walls, the intensity of solutal convection (solutal Grashof number $Grs=7.86{\times}10^6$) is greater than that of thermal convection (thermal Grashof number $Grt=4.83{\times}10^5$) by one order of magnitude, which is based on the solutally buoyancy-driven convection due to the disparity in the molecular weights of the component A ($Hg_2Cl_2$) and B (He). With increasing the partial pressure of component B from 20 up to 800 Torr, the rate is decreased exponentially. It is also interesting that as the partial pressure of component B is increased by a factor of 2, the rate is approximately reduced by a half. For systems under consideration, the rate increases linearly and directly with the dimensionless Peclet number which reflects the intensity of condensation and sublimation at the crystal and source region. The convective transport decreases with lower g level and is changed to the diffusive mode at $0.1g_0$. In other words, for regions in which the g level is $0.1g_0$ or less, the diffusion-driven convection results in a parabolic velocity profile and a recirculating cell is not likely to occur. Therefore a gravitational acceleration level of less than $0.1g_0$ can be adequate to ensure purely diffusive transport.

세라믹스 몰탈내의 철근 부식 메카니즘 (Corrosion Mechanism of Reinforcing Steel in Ceramic Mortar)

  • 김영만;이강봉;조원일;고재식;최범석;이지영;김영상
    • 분석과학
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    • 제14권4호
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    • pp.364-370
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    • 2001
  • 염분을 함유한 몰탈 환경하에서 기존의 시멘트 몰탈을 대체할 수 있는 석고계 세라믹 몰탈 내의 철근의 부식 현상을 자연전위법, EPMA 분석, 외관조사, 무게 손실정도, 용출 실험에 의해 고찰하였다. 부식 가속화 장치를 이용하여 단기간 내에 부식 현상을 예측하였으며, 관찰된 외관 모습과 무게 손실정도를 통하여 부식 유무를 판단할 수 있었고, 실제 공시체 시료의 용출 실험을 통해 pH의 영향보다는 부식 메카니즘에 ${SO_4}^{2-}$의 영향이 크다는 것을 알 수 있었다.

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Maximizing TPBs through Ni-self-exsolution on GDC based composite anode in solid oxide fuel cells

  • 탄제완;이대희;김보경;김주선;문주호
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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    • pp.402.1-402.1
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    • 2016
  • The performance of solid oxide fuel cells (SOFCs) is directly related to the electrocatalytic activity of composite electrodes in which triple phase boundaries (TPBs) of metallic catalyst, oxygen ion conducting support, and gas should be three-dimensionally maximized. The distribution morphology of catalytic nanoparticle dispersed on external surfaces is of key importance for maximized TPBs. Herein in situ grown nickel nanoparticle onto the surface of fluorite oxide is demonstrated employing gadolium-nickel co-doped ceria ($Gd0.2-xNixCe0.8O2-{\delta}$, GNDC) by reductive annealing. GNDC powders were synthesized via a Pechini-type sol-gel process while maximum doping ratio of Ni into the cerium oxide was defined by X-ray diffraction. Subsequently, NiO-GNDC composite were screen printed on the both sides of yttrium-stabilized zirconia (YSZ) pellet to fabricate the symmetrical half cells. Electrochemical impedance spectroscopy (EIS) showed that the polarization resistance was decreased when it was compared to conventional Ni-GDC anode and this effect became greater at lower temperature. Ex situ microstructural analysis using scanning electron microscopy after the reductive annealing exhibited the exsolution of Ni nanoparticles on the fluorite phases. The influence of Ni contents in GNDC on polarization characteristics of anodes were examined by EIS under H2/H2O atmosphere. Finally, the addition of optimized GNDC into the anode functional layer (AFL) dramatically enhanced cell performance of anode-supported coin cells.

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Role of Peptides in Rumen Microbial Metabolism - Review -

  • Wallace, R.J.;Atasoglu, C.;Newbold, C.J.
    • Asian-Australasian Journal of Animal Sciences
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    • 제12권1호
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    • pp.139-147
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    • 1999
  • Peptides are formed in the rumen as the result of microbial proteinase activity. The predominant type of activity is cysteine ptoteinase, but others, such as serine proteinases, are also present. Many species of protozoa, bacteria and fungi are involved in ptoteolysis; large animal-to-animal variability is found when proteinase activities in different animals are compared. The peptides formed from proteolysis are broken down to amino acids by peptidases. Different peptides are broken down at different rates, depending on their chemical composition and particularly their N-terminal structure. Indeed, chemical addition to the N-terminus of small peptides, such as by acetylation, causes the peptides to become stable to breakdown by the rumen microbial population; the microorganisms do not appear to adapt to hydrolyse acetylated peptides even after several weeks exposure to dietary acetylated peptides, and the amino acids present in acetylated peptides are absorbed from the small intestine. The amino acids present in some acetylated peptides remain available in nutritional trials with rats, but the nutritive value of the whole amino acid mixture is decreased by acetylation. The genus Prevotella is responsible for most of the catabolic peptidase activity in the rumen, via its dipeptidyl peptidase activities, which release dipeptides rather than free amino acids from the N-terminus of oligopeptides. Studies with dipeptidyl peptidase mutants of Prevotella suggest that it may be possible to slow the rate of peptide hydrolysis by the mixed rumen microbial population by inhibiting dipeptidyl peptidase activity of Prevotella or the rate of peptide uptake by this genus. Peptides and amino acids also stimulate the growth of rumen microorganisms, and are necessary for optimal growth rates of many species growing on tapidly fermented substrates; in rich medium, most bacteria use pre-formed amino acids for more than 90% of their amino acid requirements. Cellulolytic species are exceptional in this respect, but they still incorporate about half of their cell N from pre-formed amino acids in rich medium. However, the extent to which bacteria use ammonia vs. peptides and amino acids for protein synthesis also depends on the concentrations of each, such that preformed amino acids and peptides are probably used to a much lesser extent in vivo than many in vitro experiments might suggest.

Stability Analysis of FCHEV Energy System Using Frequency Decoupling Control Method

  • Dai, Peng;Sun, Weinan;Xie, Houqing;Lv, Yan;Han, Zhonghui
    • Journal of Power Electronics
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    • 제17권2호
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    • pp.490-500
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    • 2017
  • Fuel cell (FC) is a promising power supply in electric vehicles (EV); however, it has poor dynamic performance and short service life. To address these shortcomings, a super capacitor (SC) is adopted as an auxiliary power supply. In this study, the frequency decoupling control method is used in electric vehicle energy system. High-frequency and low-frequency demand power is provided by SC and FC, respectively, which makes full use of two power supplies. Simultaneously, the energy system still has rapidity and reliability. The distributed power system (DPS) of EV requires DC-DC converters to achieve the desired voltage. The stability of cascaded converters must be assessed. Impedance-based methods are effective in the stability analysis of DPS. In this study, closed-loop impedances of interleaved half-bridge DC-DC converter and phase-shifted full-bridge DC-DC converter based on the frequency decoupling control method are derived. The closed-loop impedance of an inverter for permanent magnet synchronous motor based on space vector modulation control method is also derived. An improved Middlebrook criterion is used to assess and adjust the stability of the energy system. A theoretical analysis and simulation test are provided to demonstrate the feasibility of the energy management system and the control method.

Electronic Structures of ANb2PS10 (A=Ag, Na) and AuNb4P2S20

  • Jung, Dong-Woon;Kim, Sung-Jin
    • Bulletin of the Korean Chemical Society
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    • 제24권6호
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    • pp.739-743
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    • 2003
  • New quaternary compounds $ANb_2PS_{10}$ (A = Na, Ag) and $AuNb_4P_2S_{20}$ were synthesized and characterized. The structures of three compounds consist of one-dimensional infinite chains built by [$Nb_2S_{12}$] and [$PS_4$] units. Cation atoms are occupied within the van der Waals gap of sulfur atoms between infinite chains to make -S…$M^+$…S- contacts. There is only one Au atom site and so crystallographically a unit cell contains four equivalent Au atoms in $AuNb_4P_2S_{20}$. This is only the half of the numbers of Na or Ag atoms in $NaNb_2PS_{10}$ or $AgNb_2PS_{10}$. The ratio between $Nb_2PS_{10}$ matrix vs the cation is, therefore, 1 : 1 for Ag and Na, but it is 2 : 1 for Au. Mixed valency in Au or Nb was expected to balance the charge in the latter compound. The electronic structures calculated based on the extended Huckel tight-binding method show that $ANb_2PS_{10}$ (A = Ag, Na) are semiconducting, while $AuNb_4P_2S_{20}$ is metallic, which is not consistent with the experimental results of these three compounds that all exhibit semiconducting property. The result of calculation suggests that $AuNb_4P_2S_{20}$ might be a magnetic insulator. Magnetic measurement experiment exactly proved that the compound is a Slater antiferromagnetic material with the Neels' temperature of 45 K. It is recognized, therefore, that electronic structure analysis is very useful to understand the properties of compounds.

콘크리트 중의 철근 부식 억제를 위한 외부전원법의 효과 (Effect of Impressed Current System for Corrosion Protection of Rebars in Concrete)

  • 문한영;김성수;김홍삼
    • 콘크리트학회지
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    • 제11권2호
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    • pp.221-230
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    • 1999
  • 콘크리트 구조물에 균열이 생겨 물과 산소의 침투확산이 용이해 지거나 또는 외부로부터 염소이온과 같은 염화물이 침투확산되어 콘크리트 중의 철근까지 도달할 경우 및 콘크리트의 중성화가 철근위치까지 진행될 경우 철근의 부동태 피막은 파괴되어 부식이 급진전 되며 콘크리트의 박리 및 탈락현상이 수반될 뿐만 아니라 구조물의 내구성이 크게 저하된다. 본 연구에서는 콘크리트 중의 철근부식을 억제하기 위한 한 방안으로 적용되는 전기방식의 이론적인 고찰과 콘크리트 내부에 다량의 염화물을 함유시키거나 또는 균열을 발생시킨 시험체에 대하여 외부전원법을 활용한 실내실험을 실시하여 철근의 방식효과에 대해 고찰하였다. 외부전원법에 의한 전기방식을 실시하여 복극량을 측정한 결과 대상 시험체 모두 NACE의 방식기준을 만족하였으며, 부식면적율의 측정결과 34 ~84%, 단면감소의 경우 84 ~ 86%의 방식효과를 확인하였다.

천궁의 종자불임에 관한 발생학적 특성 (Embryological Characteristics on Seed Sterility of Ligusticum chuanxiong Hoit.)

  • 박충헌;이만상;남궁승박;유홍섭;박희운
    • 한국약용작물학회지
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    • 제12권3호
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    • pp.209-213
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    • 2004
  • 토천궁은 개화는 되지만 종자 결실이 이루어지지 않아 주로 종근이나 뇌두에 의해 번식하므로 번식율이 매우 저조한 특성이 있다. 따라서 이의 원인을 구명하고자 자웅배우체 형성과정과 자가수분을 통한 수정현상을 보기 위하여 조사하였던 바 그 결과는 다음과 같다. 토천궁은 대소포자에서 감수분열이 정상적으로 이루어지고 배낭형성에서 난장치는 50% 정도가 정상적으로 이루어지고, 화분형성에서는 90%이상이 잘 이루어졌다. 토천궁의 배낭은 주심조직의 세포가 작아 모든 기관분열에서 관찰하기가 어려웠고 특히 토천궁은 배낭 형성체가 난장치로 발달되는 꽃은 거의 없었으며 화분립은 일부가 형성 되었다.