The fluorescence spectra and binding reaction of neutral red with nucleic acids have been studied. At pH=4.5, a new method for the determination of trace nucleic acids based on fluorescence quenching measurement was e...The fluorescence spectra and binding reaction of neutral red with nucleic acids have been studied. At pH=4.5, a new method for the determination of trace nucleic acids based on fluorescence quenching measurement was established. When 8.0×10 -6 mol/L NR is employed, the linear ranges of the calibration graphs are 0.08-2.0 μg/mL for calf thymus DNA(ctDNA), 0.12-2.2 μg/mL for fish sperm DNA(fsDNA) and 0.30-1.4 μg/mL for yeast RNA(yRNA), respectively. The corresponding detection limits are 30, 33 and 66 ng/mL, respectively. The real samples were analyzed satisfactorily.展开更多
Near-infrared emissive carbon dots(CDs) were synthesized by hydrothermal method. The as-prepared CDs exhibited a relatively high quantum yield(QY) of 33.96% in an aqueous solution, and the peak toward the near-infrare...Near-infrared emissive carbon dots(CDs) were synthesized by hydrothermal method. The as-prepared CDs exhibited a relatively high quantum yield(QY) of 33.96% in an aqueous solution, and the peak toward the near-infrared fluorescence reached 685 nm. The CDs exhibited pH-sensitive characteristics under strong acidic conditions. Even at pH = 0, the as-prepared CDs retained a high fluorescence intensity,which proved that they possessed good acid resistance. More importantly, the CDs were sensitive to the Fe3+changes in living cells. In addition, they could also be used for white and red emissive LEDs.This discovery will expand the use of aqueous-phase high QY CDs in the field of living cell sensing and imaging.展开更多
采用海面以上光谱测量方法（Above water method）,利用美国FieldSpe Dual VNIR光谱仪测量了丹麦细柱藻、中肋骨条藻、海洋褐胞藻等三种浮游植物赤潮以及红色中缢虫这一原生动物赤潮的离水辐射光谱数据.强调赤潮与正常海水的光谱差异在...采用海面以上光谱测量方法（Above water method）,利用美国FieldSpe Dual VNIR光谱仪测量了丹麦细柱藻、中肋骨条藻、海洋褐胞藻等三种浮游植物赤潮以及红色中缢虫这一原生动物赤潮的离水辐射光谱数据.强调赤潮与正常海水的光谱差异在于687～728 nm波段的特征反射峰,指出了浮游植物赤潮与原生动物赤潮间的显著光谱差异,并认为可据此进行某些赤潮种类的遥感识别.给出了浮游植物赤潮光谱反射峰、吸收峰成因;红色中缢虫这一原生动物引起的水色异常,与其体内的共生藻类及浮游植物色素碎屑有关;其摄食偏好、与藻类的共生特性研究以及藻类常温下的荧光发射特性研究,将有助于加深对于红色中缢虫赤潮光谱成因的认识.展开更多
The photosynthetic characteristics of strawberry (Fragariaananassa Duch. cv. Toyonoka)leaves under illumination of identical light intensity(55-57% natural light) withdifferent light quality were studied. It was showe...The photosynthetic characteristics of strawberry (Fragariaananassa Duch. cv. Toyonoka)leaves under illumination of identical light intensity(55-57% natural light) withdifferent light quality were studied. It was showed that the chlorophyll content,maximal photochemical efficiency of PSⅡ(Fv/Fm), Fm/Fo, amount of inactive PSⅡreactioncenters (Fi-Fo) and rate of QA reduction were positively correlated with the red-light/blue-light ratios, but the chlorophyll (a/b) ratios were negatively correlated withthem. Carotenoid content of the leaves was maximum under the blue film, than under greenfilm, red film, white film and yellow film, and negatively correlated with the red/far-red ratios. The apparent quantum yield (AQY), photorespiratory rate (Pr) and carboxylationefficiency (CE) were also strongly affected by light quality. The photosynthetic rate(Pn) in strawberry leaves under green film was significantly lower than under all otherfilm. Our results suggested that light quality is an essential factor regulating thedevelopment of PSⅡ, and phytochrome and an independent blue light photoreceptor,possibly a cryptochrome, can regulate photosynthetic performance.展开更多
Red emissive carbon dots(CDs)powder was synthesized on a large scale from phloroglucinol and boric acid by a novel solid state reaction with yield up to 75%.This method is safe and convenient,for it needs neither high...Red emissive carbon dots(CDs)powder was synthesized on a large scale from phloroglucinol and boric acid by a novel solid state reaction with yield up to 75%.This method is safe and convenient,for it needs neither high pressure reactors nor complicated post-treatment procedures.The as-prepared carbon dots powder exhibited strong red fluorescence with excitation-independent behavior.XPS measurement and PL spectra suggest that such red fluorescence arise from boron-doped structures in CDs,which increases along with the boron concentration on CDs surface but decreases when the concentration quenching effect takes place.To overcome the aggregation induced fluorescence quenching of the solid CDs powder,the conventional methods are dispersing CDs into a large amount of inert substrates.But our present work provides a new strategy to realize strong red fluorescence of CDs in solid state.As a result,such carbon dots powder works well for latent fingerprint identification on various material surfaces.展开更多
文摘The fluorescence spectra and binding reaction of neutral red with nucleic acids have been studied. At pH=4.5, a new method for the determination of trace nucleic acids based on fluorescence quenching measurement was established. When 8.0×10 -6 mol/L NR is employed, the linear ranges of the calibration graphs are 0.08-2.0 μg/mL for calf thymus DNA(ctDNA), 0.12-2.2 μg/mL for fish sperm DNA(fsDNA) and 0.30-1.4 μg/mL for yeast RNA(yRNA), respectively. The corresponding detection limits are 30, 33 and 66 ng/mL, respectively. The real samples were analyzed satisfactorily.
基金financially supported by the China Postdoctoral Science Foundation (2018M640681, 2019T120632)the National Natural Science Foundation of China (21774041, 51433003)the National Key Research and Development Program of China (2016YFB0401701)
文摘Near-infrared emissive carbon dots(CDs) were synthesized by hydrothermal method. The as-prepared CDs exhibited a relatively high quantum yield(QY) of 33.96% in an aqueous solution, and the peak toward the near-infrared fluorescence reached 685 nm. The CDs exhibited pH-sensitive characteristics under strong acidic conditions. Even at pH = 0, the as-prepared CDs retained a high fluorescence intensity,which proved that they possessed good acid resistance. More importantly, the CDs were sensitive to the Fe3+changes in living cells. In addition, they could also be used for white and red emissive LEDs.This discovery will expand the use of aqueous-phase high QY CDs in the field of living cell sensing and imaging.
基金supported by the National Natura1 Science Foundation of China(39730340)
文摘The photosynthetic characteristics of strawberry (Fragariaananassa Duch. cv. Toyonoka)leaves under illumination of identical light intensity(55-57% natural light) withdifferent light quality were studied. It was showed that the chlorophyll content,maximal photochemical efficiency of PSⅡ(Fv/Fm), Fm/Fo, amount of inactive PSⅡreactioncenters (Fi-Fo) and rate of QA reduction were positively correlated with the red-light/blue-light ratios, but the chlorophyll (a/b) ratios were negatively correlated withthem. Carotenoid content of the leaves was maximum under the blue film, than under greenfilm, red film, white film and yellow film, and negatively correlated with the red/far-red ratios. The apparent quantum yield (AQY), photorespiratory rate (Pr) and carboxylationefficiency (CE) were also strongly affected by light quality. The photosynthetic rate(Pn) in strawberry leaves under green film was significantly lower than under all otherfilm. Our results suggested that light quality is an essential factor regulating thedevelopment of PSⅡ, and phytochrome and an independent blue light photoreceptor,possibly a cryptochrome, can regulate photosynthetic performance.
基金financially supported by the National Natural Science Foundation of China(Nos.21975048,21771039)the Science and Technology Commission of Shanghai Municipality(No.19DZ2270100)。
文摘Red emissive carbon dots(CDs)powder was synthesized on a large scale from phloroglucinol and boric acid by a novel solid state reaction with yield up to 75%.This method is safe and convenient,for it needs neither high pressure reactors nor complicated post-treatment procedures.The as-prepared carbon dots powder exhibited strong red fluorescence with excitation-independent behavior.XPS measurement and PL spectra suggest that such red fluorescence arise from boron-doped structures in CDs,which increases along with the boron concentration on CDs surface but decreases when the concentration quenching effect takes place.To overcome the aggregation induced fluorescence quenching of the solid CDs powder,the conventional methods are dispersing CDs into a large amount of inert substrates.But our present work provides a new strategy to realize strong red fluorescence of CDs in solid state.As a result,such carbon dots powder works well for latent fingerprint identification on various material surfaces.
