A bandgap voltage reference is presented with a piecewise linear compensating circuit in order to reduce the temperature coefficient.The basic principle is to divide the whole operating temperature range into some su...A bandgap voltage reference is presented with a piecewise linear compensating circuit in order to reduce the temperature coefficient.The basic principle is to divide the whole operating temperature range into some sub ranges.At different temperature sub ranges the bandgap reference can be compensated by different linear functions.Since the temperature sub range is much narrower than the whole range,the compensation error can be reduced significantly.Theoretically,the precision can be improved unlimitedly if the sub ranges are narrow enough.In the given example,with only three temperature sub ranges,the temperature coefficient of a conventional bandgap reference drops from 1 5×10 -5 /℃ to 2×10 -6 /℃ over the -40℃ to 120℃ temperature range.展开更多
[目的]探讨WP1130与顺铂联合用药对鼻咽癌细胞增殖和转移的影响及其可能机制。[方法]CCK-8法检测鼻咽癌顺铂敏感细胞系HNE1和顺铂耐药细胞系HNE1/DDP的顺铂药物半抑制浓度(IC_(50)),以及不同浓度WP1130对鼻咽癌细胞活力的影响;选取适当...[目的]探讨WP1130与顺铂联合用药对鼻咽癌细胞增殖和转移的影响及其可能机制。[方法]CCK-8法检测鼻咽癌顺铂敏感细胞系HNE1和顺铂耐药细胞系HNE1/DDP的顺铂药物半抑制浓度(IC_(50)),以及不同浓度WP1130对鼻咽癌细胞活力的影响;选取适当药物浓度处理细胞,两种鼻咽癌细胞系分别分为4组:空白对照组(DMSO)、DDP单药组(6μmol/L顺铂)、WP1130单药组(1.25μmol/L WP1130)以及DDP+WP1130联合用药组(6μmol/L顺铂+1.25μmol/L WP1130)。MTT法检测鼻咽癌细胞增殖能力;细胞划痕实验检测鼻咽癌细胞迁移能力;Transwell侵袭实验检测鼻咽癌细胞侵袭能力;RT-PCR和Western blot实验检测顺铂耐药HNE1/DDP与亲本HNE1鼻咽癌细胞中β-catenin的表达情况以及不同药物处理对β-catenin的表达的影响。[结果]耐药HNE1/DDP细胞比亲本HNE1细胞对顺铂的耐受性提高了近5.7倍(5.17±0.33 vs 29.44±2.62,P<0.01)。β-catenin在HNE1/DDP细胞中的mRNA表达上调约3.4倍(1.00±0.26 vs 3.44±0.39,P<0.01)。与空白对照组和单药组相比,顺铂+WP1130联合用药组细胞中β-catenin的表达显著下调(HNE1:1.00±0.06 vs 0.78±0.07 vs 0.32±0.05,P<0.05;HNE1/DDP:1.01±0.05 vs 0.57±0.07 vs 0.39±0.07,P<0.05),顺铂+WP1130联合用药组细胞增殖、迁移和侵袭能力均显著下降(P均<0.01)。[结论]WP1130与顺铂联合用药可以通过下调β-catenin的表达增强顺铂对细胞增殖、迁移和侵袭的抑制作用,从而增强鼻咽癌细胞的化疗敏感性。展开更多
文摘A bandgap voltage reference is presented with a piecewise linear compensating circuit in order to reduce the temperature coefficient.The basic principle is to divide the whole operating temperature range into some sub ranges.At different temperature sub ranges the bandgap reference can be compensated by different linear functions.Since the temperature sub range is much narrower than the whole range,the compensation error can be reduced significantly.Theoretically,the precision can be improved unlimitedly if the sub ranges are narrow enough.In the given example,with only three temperature sub ranges,the temperature coefficient of a conventional bandgap reference drops from 1 5×10 -5 /℃ to 2×10 -6 /℃ over the -40℃ to 120℃ temperature range.
文摘[目的]探讨WP1130与顺铂联合用药对鼻咽癌细胞增殖和转移的影响及其可能机制。[方法]CCK-8法检测鼻咽癌顺铂敏感细胞系HNE1和顺铂耐药细胞系HNE1/DDP的顺铂药物半抑制浓度(IC_(50)),以及不同浓度WP1130对鼻咽癌细胞活力的影响;选取适当药物浓度处理细胞,两种鼻咽癌细胞系分别分为4组:空白对照组(DMSO)、DDP单药组(6μmol/L顺铂)、WP1130单药组(1.25μmol/L WP1130)以及DDP+WP1130联合用药组(6μmol/L顺铂+1.25μmol/L WP1130)。MTT法检测鼻咽癌细胞增殖能力;细胞划痕实验检测鼻咽癌细胞迁移能力;Transwell侵袭实验检测鼻咽癌细胞侵袭能力;RT-PCR和Western blot实验检测顺铂耐药HNE1/DDP与亲本HNE1鼻咽癌细胞中β-catenin的表达情况以及不同药物处理对β-catenin的表达的影响。[结果]耐药HNE1/DDP细胞比亲本HNE1细胞对顺铂的耐受性提高了近5.7倍(5.17±0.33 vs 29.44±2.62,P<0.01)。β-catenin在HNE1/DDP细胞中的mRNA表达上调约3.4倍(1.00±0.26 vs 3.44±0.39,P<0.01)。与空白对照组和单药组相比,顺铂+WP1130联合用药组细胞中β-catenin的表达显著下调(HNE1:1.00±0.06 vs 0.78±0.07 vs 0.32±0.05,P<0.05;HNE1/DDP:1.01±0.05 vs 0.57±0.07 vs 0.39±0.07,P<0.05),顺铂+WP1130联合用药组细胞增殖、迁移和侵袭能力均显著下降(P均<0.01)。[结论]WP1130与顺铂联合用药可以通过下调β-catenin的表达增强顺铂对细胞增殖、迁移和侵袭的抑制作用,从而增强鼻咽癌细胞的化疗敏感性。
