排序方式: 共有42条查询结果,搜索用时 750 毫秒
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Oliveira M. Dart-Mao Cheung C. Al-Zayed A. Chio I.-F.F. Swisher R.R. Lecuyer F. DeLisio M.P. 《Antennas and Propagation, IEEE Transactions on》2002,50(5):698-702
Grid-mixer arrays can achieve high linearity and dynamic range through quasi-optical power combining. We present a 100-element single-ended diode grid mixer operating at 2.45 GHz. Each element incorporates two diodes in series. We measure an input third-order intercept of 11 W (40.5 dBm), and output third-order intercept of 3.4 W (35.4 dBm), and an associated conversion loss of 5.1 dB. The power-handling capability of the array is 100 times larger than that of a microstrip mixer using a single element. The local oscillator (LO) drive requirement for the entire array is 1.4 W (31.6 dBm). The angular dependence of the array's IF power is also presented and is in agreement with theory 相似文献
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Cynthia M. Chio Karen W. Cheng Prof. Anthony C. Bishop 《Chembiochem : a European journal of chemical biology》2015,16(12):1735-1739
Few chemical strategies for activating enzymes have been developed. Here we show that a biarsenical compound (FlAsH) can directly activate a rationally engineered protein tyrosine phosphatase (Shp2 PTP) by disrupting autoinhibitory interactions between Shp2's N‐terminal SH2 domain and its PTP domain. We found that introducing a tricysteine motif at a loop of Shp2's N‐SH2 domain confers affinity for FlAsH; binding of FlAsH to the cysteine‐enriched loop relieves Shp2's inhibitory interdomain interaction and substantially increases the enzyme's PTP activity. Activation of engineered Shp2 is substrate independent and is observed in the contexts of both purified enzyme and complex proteomes. A chemical means for activating Shp2 could be useful for investigating its roles in signaling and oncogenesis, and the loop‐targeting strategy described herein could provide a blueprint for the development of target‐specific activators of other autoinhibited enzymes. 相似文献
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Liao CM Chio CP Chen WY Ju YR Li WH Cheng YH Liao VH Chen SC Ling MP 《Journal of hazardous materials》2011,190(1-3):150-158
Exposures to carcinogenic polycyclic aromatic hydrocarbons (PAHs) have been linked to human lung cancer. The purpose of this study was to assess lung cancer risk caused by inhalation exposure to nano/ultrafine particle-bound PAHs at the population level in Taiwan appraised with recent published data. A human respiratory tract model was linked with a physiologically based pharmacokinetic model to estimate deposition fraction and internal organic-specific PAHs doses. A probabilistic risk assessment framework was developed to estimate potential lung cancer risk. We reanalyzed particle size distribution, total-PAHs, particle-bound benzo(a)pyrene (B[a]P) and PM concentrations. A dose-response profile describing the relationships between external B[a]P concentration and lung cancer risk response was constructed based on population attributable fraction (PAF). We found that 90% probability lung cancer risks ranged from 10(-5) to 10(-4) for traffic-related nano and ultrafine particle-bound PAHs, indicating a potential lung cancer risk. The particle size-specific PAF-based excess annual lung cancer incidence rate due to PAHs exposure was estimated to be less than 1 per 100,000 population, indicating a mild risk factor for lung cancer. We concluded that probabilistic risk assessment linked PAF for limiting cumulative PAHs emissions to reduce lung cancer risk plays a prominent role in future government risk assessment program. 相似文献
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Francesco Dolci Marco Di Chio Marcello Baricco Elio Giamello 《Journal of Materials Science》2007,42(17):7180-7185
Nb2O5 is known as good promoter for adsorption/desorption kinetics of hydrogen in magnesium hydride. In this article the interaction
with hydrogen of bare Nb2O5, the oxidic component of the mixed MgH2/Nb2O5 system, is investigated in various conditions (i.e. employing atomic, molecular and nascent hydrogen). The state of the hydrogen-Nb2O5 system was monitored using various techniques including: X-ray Diffraction, Electron Paramagnetic Resonance, Diffuse Reflectance
UV-Vis Spectroscopy, Thermal Desorption Spectroscopy -Mass Spectrometry, Differential Scanning Calorimetry and Thermal Programmed
Desorption. Niobium (V) oxide is not at all inert while interacting with hydrogen. This oxide is partially reduced by hydrogen,
which is incorporated in the solid and released as both molecular hydrogen and water. This peculiar behaviour, reminiscent
of some properties of the bronze family, suggests an active chemical role played by Nb2O5 in the mixed MgH2/Nb2O5 system. 相似文献
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研究利用多杀菌素对蚊子幼虫致死率与其浓度的相关性,以蚊子幼虫为靶标动物建立基于活体筛选的多杀菌素高产菌株高通量快速筛选模型.通过比较蚊子幼虫的致死率筛选获得多杀菌素产量较高的菌株.结果显示:2龄埃及伊蚊幼虫具有高的敏感性和精确性,生测曲线拟合获得的毒力回归方程标准误差(SE)较小,最适宜作为供试虫源用于快速初筛模型.方法能显著提高多杀菌素高产菌株的筛选效率. 相似文献
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The purpose of this study was to investigate the effects of size and phase composition on human exposure to airborne titanium dioxide (TiO(2)) nanoparticles (NPs) at workplaces. We reanalyzed published data of particle size distribution of airborne TiO(2) NPs during manufacturing activities and linked a physiologically based lung model to estimate size- and phase-specific TiO(2) NP burdens in target lung cells. We also adopted a cell model to simulate the exposure time-dependent size/phase-specific cell uptake of TiO(2) NPs in human dermal and lung cells. Combining laboratory, field, and modeling results, we proposed two major findings: (i) the estimated median effective anatase TiO(2) NP concentration (EC50) for cytotoxicity response on human dermal fibroblasts was estimated to be 24.84 (95% CI: 7.3-70.2) nmolmL(-1) and EC50 estimate for inflammatory response on human lung epithelial cells was 5414 (95% CI: 3370-7479) nmolmL(-1) and (ii) packers and surface treatment workers at the TiO(2) NP production workplaces are unlikely to pose substantial risk on lung inflammatory response. Nevertheless, our findings point out that TiO(2) NP production workers have significant risk on cytotoxicity response at relatively high airborne anatase TiO(2) NP concentrations at size range 10-30nm. 相似文献
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Chih-Wei Chen Cheng-Han Yang Yuan-Ho Lin Ya-Chin Hou Tain-Junn Cheng Sheng-Tsung Chang Yu-Hua Huang Shang-Ting Chung Chung-Ching Chio Yan-Shen Shan Hung-Chi Cheng Wen-Tsan Chang 《International journal of molecular sciences》2021,22(7)
Due to the increasing incidence of malignant gliomas, particularly glioblastoma multiforme (GBM), a simple and reliable GBM diagnosis is needed to screen early the death-threaten patients. This study aimed to identify a protein that can be used to discriminate GBM from low-grade astrocytoma and elucidate further that it has a functional role during malignant glioma progressions. To identify proteins that display low or no expression in low-grade astrocytoma but elevated levels in GBM, glycoprotein fibronectin (FN) was particularly examined according to the mining of the Human Protein Atlas. Web-based open megadata minings revealed that FN was mainly mutated in the cBio Cancer Genomic Portal but dominantly overexpressed in the ONCOMINE (a cancer microarray database and integrated data-mining platform) in distinct tumor types. Furthermore, numerous different cancer patients with high FN indeed exhibited a poor prognosis in the PrognoScan mining, indicating that FN involves in tumor malignancy. To investigate further the significance of FN expression in glioma progression, tumor specimens from five malignant gliomas with recurrences that received at least two surgeries were enrolled and examined. The immunohistochemical staining showed that FN expression indeed determined the distinct progressions of malignant gliomas. Furthermore, the expression of vimentin (VIM), a mesenchymal protein that is strongly expressed in malignant cancers, was similar to the FN pattern. Moreover, the level of epithelial–mesenchymal transition (EMT) inducer transforming growth factor-beta (TGF-β) was almost recapitulated with the FN expression. Together, this study identifies a protein FN that can be used to diagnose GBM from low-grade astrocytoma; moreover, its expression functionally determines the malignant glioma progressions via TGF-β-induced EMT pathway. 相似文献