Oxidation of fats and oils during storage causes their degradation and loss of nutritional value and appearance. Electron spin resonance （ESR） is the only method that can be used to directly observe the radicals. In...Oxidation of fats and oils during storage causes their degradation and loss of nutritional value and appearance. Electron spin resonance （ESR） is the only method that can be used to directly observe the radicals. In this study, the authors used an ESR spin-trapping method to study the oxidation of triacylglycerols （TAG） containing different fatty acids （FAs） commonly found in food. The ESR adduct signals were analyzed to study the effect of double bonds and the chain length of the FAs of TAG on oxidation. Oxidation was conducted by applying UV irradiation to TAG by dissolving it in N-tert-buthyl〈t-phenylnitrone （PBN）, which trapped the radicals induced in the TAG as an ESR adduct signal. The detection was clearly successful. There were no differences in the spectra of tristearin （18：0） and tripalmitin （16：0）; thus, it can be concluded that the length of the carbon chain of the FAs of TAG does not affect the oxidation reactions. However, the ESR spectra of tristearin （18：0）, triolein （18：1） and trilinolein （18：3） were clearly different due to the presence/absence of a new peak corresponding to new induced radicals, leading to the conclusion that double bonds play a major role in the oxidation reactions of fats and oils.展开更多
The purpose of this study was to examine the behavioral impact of varying LED （light emitting diode） spectral emissions on avian species. A novel oculo-neuro-motor response to monochromatic LEDs has been identified....The purpose of this study was to examine the behavioral impact of varying LED （light emitting diode） spectral emissions on avian species. A novel oculo-neuro-motor response to monochromatic LEDs has been identified. LED colored light of sufficient intensity matched to the short-wavelength cones of avian species can efficiently diminish overall visual perception leading to an augmented behavioral response. The study method involved monitoring the change in behavioral response after exposure to high brightness monochromatic LED light to wild Osprey （Pandion haliaetus） foraging and nesting in their natural environment. Our results demonstrated a statistically significant change in foraging behaviors with wild Osprey （p = 0.005） and in nesting behavior as a result of exposure to high brightness monochromatic LED light. An augmented behavioral responses was observed which is believed to be analogous to human reaction to solar glare and glint. The neuroimaging mechanism of avian species is discussed. This novel augmented behavioral response provides a new technique of studying the neuroscience of temporal and spatial light stimulus. A non-lethal deterrence technique involving the augmented behavioral response could mitigate mortality and morbidity of avian-human conflict in areas such as airports, airplane bird strikes, and wind turbines.展开更多
A photochromic rhodamine B-based material containing Cd（Ⅱ） as bridge was facilely prepared. The 4-methoxylsalicylalde hyde rhodamine B bydrazone Cd（Ⅱ） complex displayed unusual ring-open response upon 365 nm UV ...A photochromic rhodamine B-based material containing Cd（Ⅱ） as bridge was facilely prepared. The 4-methoxylsalicylalde hyde rhodamine B bydrazone Cd（Ⅱ） complex displayed unusual ring-open response upon 365 nm UV irradiation, exhibiting long photochromic lifetime and good fatigue resistance. The UV-induced ring-open of the complex led to a distinct color and fluorescence change in acetonitrile. A new mechanism was put forward： salicylaldehyde part in the complex underwent UV-promoted isomerization from enol-form to keto-form, enhancing the chelation of Cd（Ⅱ） and yielding the ring-opening rhodamine B part. Compared to other reported photochromic systems, this new photochromic material offered attractive new insights into the development of low cost photochromic materials with good performance.展开更多
We report fabrication and characterization of metal-semiconductor-metal photoconductive detectors based on Al-doped ZnO thin films fabricated by radio frequency magnetron sputtering.Optical and structural properties o...We report fabrication and characterization of metal-semiconductor-metal photoconductive detectors based on Al-doped ZnO thin films fabricated by radio frequency magnetron sputtering.Optical and structural properties of the thin films were characterized using various techniques.At 6 V bias,a responsivity higher than 4 A/W in the wavelength shorter than 350 nm was obtained,and this responsibility dropped quickly and reached the noise floor in the visible region.Transient response measurement revealed that the detector had a fast photoresponse with a rise time of 9 ns and a fall time of 1.2 μs.展开更多
文摘Oxidation of fats and oils during storage causes their degradation and loss of nutritional value and appearance. Electron spin resonance （ESR） is the only method that can be used to directly observe the radicals. In this study, the authors used an ESR spin-trapping method to study the oxidation of triacylglycerols （TAG） containing different fatty acids （FAs） commonly found in food. The ESR adduct signals were analyzed to study the effect of double bonds and the chain length of the FAs of TAG on oxidation. Oxidation was conducted by applying UV irradiation to TAG by dissolving it in N-tert-buthyl〈t-phenylnitrone （PBN）, which trapped the radicals induced in the TAG as an ESR adduct signal. The detection was clearly successful. There were no differences in the spectra of tristearin （18：0） and tripalmitin （16：0）; thus, it can be concluded that the length of the carbon chain of the FAs of TAG does not affect the oxidation reactions. However, the ESR spectra of tristearin （18：0）, triolein （18：1） and trilinolein （18：3） were clearly different due to the presence/absence of a new peak corresponding to new induced radicals, leading to the conclusion that double bonds play a major role in the oxidation reactions of fats and oils.
基金This work was supported by grant No. IIP-1350562 from the National Science Foundation. NH Audubon Society provided assistance in tabulating the field results. Support at the test sites was provided by US Cellular, and NH Fish and Game Department--Milford Fish Hatchery.
文摘The purpose of this study was to examine the behavioral impact of varying LED （light emitting diode） spectral emissions on avian species. A novel oculo-neuro-motor response to monochromatic LEDs has been identified. LED colored light of sufficient intensity matched to the short-wavelength cones of avian species can efficiently diminish overall visual perception leading to an augmented behavioral response. The study method involved monitoring the change in behavioral response after exposure to high brightness monochromatic LED light to wild Osprey （Pandion haliaetus） foraging and nesting in their natural environment. Our results demonstrated a statistically significant change in foraging behaviors with wild Osprey （p = 0.005） and in nesting behavior as a result of exposure to high brightness monochromatic LED light. An augmented behavioral responses was observed which is believed to be analogous to human reaction to solar glare and glint. The neuroimaging mechanism of avian species is discussed. This novel augmented behavioral response provides a new technique of studying the neuroscience of temporal and spatial light stimulus. A non-lethal deterrence technique involving the augmented behavioral response could mitigate mortality and morbidity of avian-human conflict in areas such as airports, airplane bird strikes, and wind turbines.
基金financially supported by the National Natural Science Foundation of China(21175079 and 21375074)
文摘A photochromic rhodamine B-based material containing Cd（Ⅱ） as bridge was facilely prepared. The 4-methoxylsalicylalde hyde rhodamine B bydrazone Cd（Ⅱ） complex displayed unusual ring-open response upon 365 nm UV irradiation, exhibiting long photochromic lifetime and good fatigue resistance. The UV-induced ring-open of the complex led to a distinct color and fluorescence change in acetonitrile. A new mechanism was put forward： salicylaldehyde part in the complex underwent UV-promoted isomerization from enol-form to keto-form, enhancing the chelation of Cd（Ⅱ） and yielding the ring-opening rhodamine B part. Compared to other reported photochromic systems, this new photochromic material offered attractive new insights into the development of low cost photochromic materials with good performance.
基金supported by the National Natural Science Foundation of China (Grant No.50972007)the Beijing Municipal Natural Science Foundation (Grant No.4092035)+3 种基金the State Key Program for Basic Research of the Ministry of Science and Technology of China (Grant No.2011CB932703)the Special Items Fund of Beijing Municipal Commission of Educationthe Opened Fund of State Key Laboratory on Integrated Optoelectronicsthe National Science Fund for Distinguished Young Scholars (Grant No.60825407)
文摘We report fabrication and characterization of metal-semiconductor-metal photoconductive detectors based on Al-doped ZnO thin films fabricated by radio frequency magnetron sputtering.Optical and structural properties of the thin films were characterized using various techniques.At 6 V bias,a responsivity higher than 4 A/W in the wavelength shorter than 350 nm was obtained,and this responsibility dropped quickly and reached the noise floor in the visible region.Transient response measurement revealed that the detector had a fast photoresponse with a rise time of 9 ns and a fall time of 1.2 μs.
