• 제목/요약/키워드: bias effect

Search Result 1,492, Processing Time 0.032 seconds

High Performance $2{\times}4$ S-SEED Array with Extremely Shallow Quantum Well and Asymmetric Fabry-Peort Cavity Structure (저장벽 양자우물고조와 비대칠 패브리-페로 공명기 구조에 의한 고성능 $2{\times}4$ S-SEED Array 구현)

  • 권오균;최영완;김광준;이일항;이상훈;원용협;유형모
    • Korean Journal of Optics and Photonics
    • /
    • v.5 no.1
    • /
    • pp.144-151
    • /
    • 1994
  • We designed and fabricated a $2{\times}4$ symmetric self electro-optic effect device array using GaAs/ AIo.04 G$\DeltaR$), and optical bistability loop width ($\Delta$). The average values of the elements of the $2{\times}4$ S-SEED array were CR~13.1, R~24%, and $\Delta$~91%. It was found that the AFP cavity structure enhances the self-biased optical bistability in ESQW-SEED under no external bias. That is due to the decreased intrisic region thickness in AFP-SEED structures, and which increases the built-in electric fields. The zero-biased S-SEED showed CR of ~4.7, R~9%, and $\Delta$~22%.X>~22%.

  • PDF

Association Between Green Tea and Colorectal Cancer Risk: A Meta-analysis of 13 Case-control Studies

  • Wang, Xue-Jun;Zeng, Xian-Tao;Duan, Xiao-Li;Zeng, Huan-Chao;Shen, Rui;Zhou, Ping
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.13 no.7
    • /
    • pp.3123-3127
    • /
    • 2012
  • Objective: Experimental studies have suggested green tea to be a chemopreventive agent for colorectal cancer, and many studies have examined possible associations. However, the conclusions were inconsistent or even contradictory, so we performed a meta-analysis based on published case-control studies to explore if green tea is indeed a protective factor. Methods: PubMed was searched up to May $10^{th}$, 2012 for relevant studies, and references of included studies were manually searched. Finally 13 eligible studies, involving 12,636 cases and 38,419 controls were identified. After data extraction, a meta-analysis was performed using CMA v2 software. Results: The results indicated there may be a weak but not statistically significant reduced risk of colorectal cancer with high dose of green tea intake (OR=0.95, 95% CI:0.81-1.11, p=0.490.69-0.98). This protective effect was also found in all subgroups, except in American and European populations. Sensitivity analysis indicated the result to be robust. Publication bias was not detected by either funnel plot or Egger tests. Conclusion: The results of this meta-analysis indicate a weak lower tendency for colorectal cancer development with green tea consumption, but available epidemiologic data are insufficient to conclude that green tea may protect against colorectal cancer in humans.

Meta-analysis of Six Randomized Control Trials of Chemotherapy Plus Anti-HER Monoclonal Antibody for Advanced Gastric and Gastroesophageal Cancer

  • Luo, Huai-Qing;Han, Li;Jiang, Yan
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.15 no.13
    • /
    • pp.5343-5348
    • /
    • 2014
  • Background: A meta-analysis was performed to examine the benefit/risk ratio for the addition of anti- HER MoAbs to chemotherapy in patients with advanced gastric and gastroesophageal cancer from six randomized phase II/III trials. Materials and Methods: We searched relative trials from Pubmed, EMBASE, Cochrane library databases, China National Knowledge Infrastructure databases, Google Scholar and the NIH ClinicalTrials. Primary outcomes were overall response rate (ORR), progression-free survival (PFS), overall survival (OS). Secondary outcomes were toxicities. All analyses were performed using STATA 12.0. Results: This meta-analysis included six randomized controlled trials (RCTs) with 2, 297 patients and we demonstrated that the anti-HER MoAbs arm did have a positive effect on ORR in the anti-HER MoAbs arm (OR 1.28, 95% CI 1.00-1.64, p=0.01). There was an increasing benefit regarding OS (HR 0.74, 95% CI 0.60-0.88, p<0.05) and PFS (HR 0.72, 95% CI 0.60-0.84, p<0.05) in the anti-HER2 subgroup, but a reduction of OS (HR 1.11, 95% CI 0.87-1.36, p<0.05) and PFS (HR 1.13, 95% CI 0.98 -1.28, P<0.05) in anti-EGFR subgroup. Some grade 3-4 toxicity had a significantly higher incidence in the anti-HER MoAbs arm. There was no significant publication bias for all endpoints. Conclusions: The addition of trstuzumab MoAb to chemotherapy for gastric and gastroesophageal cancer significantly improved outcome of OS and PFS endpoints, while other MoAbs led to no improvement in results. Some adverse events were increased in anti-HER MoAbs arm compared with the control.

Daoyin Exercise Therapy for Stroke : A Systematic Review (뇌졸중에 대한 도인 운동요법의 효과: 체계적 문헌 고찰)

  • Lee, Sang-Hyun;Shin, Byung-Cheul;Hwang, Eui-Hyoung;Heo, In;Park, Sun-Young;Hwang, Man-Suk
    • The Journal of Churna Manual Medicine for Spine and Nerves
    • /
    • v.14 no.2
    • /
    • pp.29-42
    • /
    • 2019
  • Objectives : This study aimed to review the effects of Daoyin exercise on stroke patients in clinical studies. Methods : In this study, we reviewed 11 electronic databases (CAJ, EMBASE, Cochrane Library, Web of Science, Pubmed, RISS, Dbpia, NDSL, KISTI, KISS, KMBASE) on October 27, 2019. We included only randomized controlled trials (RCTs) which evaluated the effect of Daoyin exercise on stroke patients. The methodological quality of the included studies was checked using the Cochrane risk of bias tool. Results : After screening the papers, eleven RCTs fulfilled the inclusion criteria. The results of the meta-analysis showed that Daoyin exercise improves the measurement value on the Fugl-Meyer Assessment, Modified Barthel Index and National Institutes of Health Stroke Scale in stroke patients. Conclusions : We concluded that Daoyin exercise has therapeutic effects in functional recovery and in enhancing the independence of daily living activities for stroke patients. However, the quality of the original articles was low and the number of papers included were few. Thus, to confirm these results, further well-designed RCTs should be conducted.

Association of the PTEN IVS4 (rs3830675) Gene Polymorphism with Reduced Risk of Cancer: Evidence from a Meta-analysis

  • Mandal, Raju K.;Akhter, Naseem;Irshad, Mohammad;Panda, Aditya K.;Ali, Arif;Haque, Shafiul
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.16 no.3
    • /
    • pp.897-902
    • /
    • 2015
  • PTEN (phosphatase and tensin homologue), as a tumor suppressor gene, plays a significant role in regulating cell growth, proliferation, and apoptosis. Results from published studies for association between the PTEN IVS4 I/D (rs3830675) polymorphism and cancer risk are inconsistent and inconclusive. We therefore conducted a meta-analysis to evaluate the potential association between PTEN IVS4 I/D polymorphism and risk of cancer in detail. We searched PubMed (Medline) and EMBASE web databases to cover all relevant studies published until December 2013. The meta-analysis was carried out and pooled odds ratios (ORs) and 95% confidence intervals (95%CIs) were used to appraise the strength of association. A total of 1,993 confirmed cancer cases and 3,200 controls were included from six eligible case-control studies. Results from overall pooled analysis suggested a significant effect of the PTEN IVS4 I/D polymorphism and cancer risk in all genetic models, i.e., allele (I vs D: OR=0.743, 95%CI=0.648 to 0.852, p=0.001), homozygous (II vs DD: OR=0.673, 95%CI=0.555 to 0.816, p=0.001), heterozygous (ID vs DD: OR=0.641, 95%CI=0.489 to 0.840, p=0.001), dominant (II+ID vs DD: OR=0.626, 95%CI=0.489 to 0.802, p=0.001) and recessive (II vs DD+ID: OR=0.749, 95%CI=0.631 to 0.889, p=0.001). Significant publication bias was detected during the analysis. The present meta-analysis suggests that the PTEN IVS4 I/D polymorphism is significantly associated with reduced risk of cancer. However, future larger studies with other groups of populations are warranted to clarify this association.

Changes in the Characteristics of Wintertime Climatology Simulation for METRI AGCM Using the Improved Radiation Parameterization (METRI AGCM의 복사 모수화 개선에 따른 겨울철 기후모의의 특징적 변화)

  • Lim, Han-Cheol;Byun, Young-Hwa;Park, Suhee;Kwon, Won-Tae
    • Atmosphere
    • /
    • v.19 no.2
    • /
    • pp.127-143
    • /
    • 2009
  • This study investigates characteristics of wintertime simulation conducted by METRI AGCM utilizing new radiation parameterization scheme. New radiation scheme is based on the method of Chou et al., and is utilized in the METRI AGCM recently. In order to analyze characteristics of seasonal simulation in boreal winter, hindcast dataset from 1979 to 2005 is produced in two experiments - control run (CTRL) and new model's run (RADI). Also, changes in performance skill and predictability due to implementation of new radiation scheme are examined. In the wintertime simulation, the RADI experiment tends to reduce warm bias in the upper troposphere probably due to intensification of longwave radiative cooling over the whole troposphere. The radiative cooling effect is related to weakening of longitudinal temperature gradient, leading to weaker tropospheric jet in the upper troposphere. In addition, changes in vertical thermodynamic structure have an influence on reduction of tropical precipitation. Moreover, the RADI case is less sensitive to variation of tropical sea surface temperature than the CTRL case, even though the RADI case simulates the mean climate pattern well. It implies that the RADI run does not have significant improvement in seasonal prediction point of view.

Characteristics Analysis of Class E Frequency Multiplier using FET Switch Model (FET 스위치 모델을 이용한 E급 주파수 체배기 특성 해석)

  • Joo, Jae-Hyun;Koo, Kyung-Heon
    • Journal of Advanced Navigation Technology
    • /
    • v.15 no.4
    • /
    • pp.596-601
    • /
    • 2011
  • This paper has presented research results for the switching mode class E frequency multiplier that has simple circuit structure and high efficiency. Frequency multiplication is coming from the nonlinearity of the active component, and this paper models the FET active component as a simple switch and some parasitics to analyze the characteristics. The matching component parameters for the class E frequency doubler have been derived with modeling the FET as a input controlled switch and some parasitics. A circuit simulator, ADS, is used to simulate the output voltage and current waveform and efficiency with the variation of the parasitic values. With 2.9GHz input and 2V bias, the drain efficiency has been decreased from 98% to 28% with changing the parasitic capacitance from 0pF to 1pF at 5.8GHz output, which shows that the parasitic capacitance CP has the most significant effect on the efficiency among the parasitics of FET.

A Study on the Fabrication of the Low Noise Amplifier Using a Series Feedback Method (직렬 피드백 기법을 이용한 저잡음 증폭기의 구현에 관한 연구)

  • 김동일;유치환;전중성;정세모
    • Journal of the Korean Institute of Navigation
    • /
    • v.25 no.1
    • /
    • pp.53-60
    • /
    • 2001
  • This paper presents the fabrication of the LNA which is operating at 2.13 ~ 2.16 GHz for IMT-2000 front-end receiver using series feedback and resistive decoupling circuit. Series feedback added to the source lead of a GaAs FET keeps the low noise characteristics and drops the input reflection coefficient of a low noise amplifier simultaneously. Also, it increases the stability of the LNA. Resistive decoupling circuit is suitable for input stage matching because a signal at low frequency is dissipated by a resistor in the matching network. The amplifier consists of GaAs FET ATF-10136 for low noise stage and VNA-25 which is internally matched MMIC for high gain stage. The amplifier is fabricated with both the RF circuits and self bias circuit on the Teflon substrate with 3.5 permittivity. The measured results of the LNA which is fabricated using the above design technique are presented more than 30 dB in gain, PldB 17 dB and less than 0.7 dB in noise figure, 1.5 in inputㆍoutput SWR(Standing Wave Ratio).

  • PDF

Electrical Characteristics Analysis of Resistive Memory using Oxygen Vacancy in V2O5 Thin Film (산소공공을 이용한 V2O5 저항성 메모리의 전기적인 동작특성 해석)

  • Oh, Teresa
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.21 no.10
    • /
    • pp.1827-1832
    • /
    • 2017
  • To observe the characteristics to be a resistive memory of $V_2O_5$ deposited by oxygen various gas flows and annealed, the hysteresis curves of $V_2O_5$ were analyzed. The good resistive memory was obtained from the electrical characteristics of $V_2O_5$ films with the Schottky contact as a result of electron-hole pair, and the oxygen vacancy generated from the annealing process contributes the high quality of Schottky contact and the formation of resistive memories. The balanced Schottky contacts owing to the oxygen vacancy effect as the result of an ionic reaction were formed at the $V_2O_5$ film annealed at $150^{\circ}C$ and $200^{\circ}C$ and the balanced Schottky contact with negative to positive voltages enhanced the electrical operation with write/erase states according to the forward or reverse bias voltages for the resistive memory behavior due to the oxygen vacancy.

Effects of thermal treatment on structural and electrical properties of DLC films deposited by FCVA method (FCVA 방법으로 증착된 DLC 박막의 열처리에 따른 구조적, 전기적 물성 분석)

  • Kim, Young-Do;Chang, Seok-Mo;Park, Chang-Kyun;Uhm, Hyun-Seok;Park, Jin-Seok
    • Proceedings of the KIEE Conference
    • /
    • 2002.07c
    • /
    • pp.1536-1538
    • /
    • 2002
  • Effects at thermal treatment on the structural and electrical properties at DLC films have been studied. The DLC films were deposited by using a modified FCVA system as a function at negative substrate bias voltage, deposition time, and nitrogen flow rate. The thermal treatment on DLC films could be achieved by performing the RTA process at $600^{\circ}C$, 2min. Structural investigation on the thermal treatment effect was evaluated by inspecting the Raman spectroscopy, XPS, AFM, and internal compressive stress. In addition, the electrical properties of DLC films were evaluated by using the high current source and Lab-View data acquisition system. As the result at RTA treatment, $sp^3/sp^2$ ratio and internal compressive stress of the DLC films were decreased tram 5% to 22% and from 1GPa to 3GPa, and the $I_D/I_G$ intensity ratios was increased from 0.19 to 0.35. It was also found that the variation of internal stress of DLC films strongly agree with the variation of $sp^3/sp^2$ fraction and $I_D/I_G$ intensity ratio.

  • PDF