This study examined the photostabilization of Azadirachtin-A （Aza-A） when exposed to ultraviolet light in the presence of some natural absorbers. Aza-A extract solutions with and without natural UV light absorbers i...This study examined the photostabilization of Azadirachtin-A （Aza-A） when exposed to ultraviolet light in the presence of some natural absorbers. Aza-A extract solutions with and without natural UV light absorbers in methanol were applied onto the surface of glass slides. At particular intervals, the remaining concentration of Aza-A was analyzed by HPLC. Using first-order kinetic equation, the dissipation half-life values （DT^0） for the degradation of Aza-A under ultraviolet radiation were obtained. It indicated that the addition of ferulic acid, gallic acid, and rutin provided moderate degree of photostabilization of Aza-A and that addition of aloin provided the best photostabilization of Aza-A, among these UV absorbers studied. Photostabilization of Aza-A by different UV light absorbers appears to be due to the competitive energy absorption of UV photons by the absorbers molecules. The dissipation half-life values of Aza-A after irradiation under ultraviolet light suggested that the addition of aloin （in 1 ： 1 mol ratio） can provide better photostabilization of azadirachtin molecule.展开更多
AIM:To determine the amount of ultraviolet(UV)light irradiance that various layers of the eye receive as sunlight passes through the eye,and to investigate the protective benefits of UV light-blocking contact lenses.M...AIM:To determine the amount of ultraviolet(UV)light irradiance that various layers of the eye receive as sunlight passes through the eye,and to investigate the protective benefits of UV light-blocking contact lenses.METHODS:Twenty-four porcine eyes were prepared in one of three ways:isolated cornea,cornea and lens together,or whole eye preparation.UV light irradiance was measured with a UV-A/B light meter before and after the eye preparations were placed over the meter to measure UV light penetration in each eye structure.In the whole eye preparation,a hole was placed in the fovea to measure light as it passed through the vitreous.Subsequently,UVprotective contact lenses were placed over the structures,and UV light penetrance was measured.Measurements of UV light exposure were taken outdoors at various locations and times.RESULTS:Cornea absorbed 63.56%of UV light that reached the eye.Cornea and lens absorbed 99.34%of UV light.Whole eye absorbed 99.77%of UV light.When UV-protective contact lenses were placed,absorption was 98.90%,99.55%,and 99.87%,respectively.UV light exposure was dependent on directionality and time of day,and was greatest in areas of high albedo that reflect significant amounts of light,such as a beach.CONCLUSION:Cornea absorbs the majority of UV light that reaches the eye in this model.UV-protective contact lenses reduce UV exposure to the eye.Locations with high albedo expose the eye to higher levels of UV light.展开更多
The AlGaN-based deep ultraviolet light-emitting diodes（LED） with double electron blocking layers（d-EBLs） on both sides of the active region are investigated theoretically. They possess many excellent performances ...The AlGaN-based deep ultraviolet light-emitting diodes（LED） with double electron blocking layers（d-EBLs） on both sides of the active region are investigated theoretically. They possess many excellent performances compared with the conventional structure with only a single electron blocking layer, such as a higher recombination rate, improved light output power and internal quantum efficiency（IQE）. The reasons can be concluded as follows. On the one hand, the weakened electrostatic field within the quantum wells（QWs） enhances the electron–hole spatial overlap in QWs, and therefore increases the probability of radioactive recombination. On the other hand, the added n-AlGaN layer can not only prevent holes from overflowing into the n-side region but also act as another electron source, providing more electrons.展开更多
The influence of ultraviolet light irradiation on the pitting corrosion performance of a Zr_(2)Ni metallic glass was examined using electrochemical methods and immersion test in 0.05 mol/L NaCl solution.From the resul...The influence of ultraviolet light irradiation on the pitting corrosion performance of a Zr_(2)Ni metallic glass was examined using electrochemical methods and immersion test in 0.05 mol/L NaCl solution.From the results of potentiostatic polarization,the pitting potential of the ultraviolet light-irradiated sample shifted positively with a value of~300 mV,revealing the enhanced pitting corrosion resistance of the samples.The corrosion morphology after the immersion test also demonstrated lower degree of corrosion damage and improved pitting resistance of the sample with ultraviolet light irradiation.X-ray photoelectron spectroscopy analysis revealed more zirconium enrichment in the passive film and no chloride ions adsorption for the samples with ultraviolet irradiation,accounting for the suppression of the pit generation and growth.Our findings indicate that ultraviolet light irradiation improves the pitting corrosion resistance of the Zr-based metallic glasses,which are promising structural materials to be used in corrosion environments with high ultraviolet irradiation.展开更多
Deep-ultraviolet（DUV） light-emitting devices（LEDs） have a variety of potential applications.Zinc-oxide-based materials,which have wide bandgap and large exciton binding energy,have potential applications in high-p...Deep-ultraviolet（DUV） light-emitting devices（LEDs） have a variety of potential applications.Zinc-oxide-based materials,which have wide bandgap and large exciton binding energy,have potential applications in high-performance DUV LEDs.To realize such optoelectronic devices,the modulation of the bandgap is required.This has been demonstrated by the developments of Mg_xZn_（1-x）O and Be_xZn_（1-x）O alloys for the larger bandgap materials.Many efforts have been made to obtain DUV LEDs,and promising successes have been achieved continuously.In this article,we review the recent progress of and problems encountered in the research of ZnO-based DUV LEDs.展开更多
Objective: The purpose of this study was to determine usefulness of antibiotic bone cement and UV light in primary Total Knee Arthroplasty (TKA). Patients and Methods: Between 1986 and 2008, 3105 TKAs were performed u...Objective: The purpose of this study was to determine usefulness of antibiotic bone cement and UV light in primary Total Knee Arthroplasty (TKA). Patients and Methods: Between 1986 and 2008, 3105 TKAs were performed using 750 mg of cefuroxime per bag of cement (Group 1), 7537 using cefuroxime and UV light (Group 2), and 4573 using UV light and gentamicin premixed (Group 3). Results: The primary infection rate was 0.57% (87 acute postoperative infections). Of these, 27 (0.9%) were in Group 1, 44 (0.6%) were in Group 2, and 16 (0.35%) were in Group 3 (p = 0.0013). Kaplan-Meier survival in Groups 1 - 3 for reoperation for aseptic loosening of any component at 5 years was 0.9908, 0.9927, and 0.9959, respectively (p = 0.1315). Conclusion: Despite potential concerns mentioned in the literature, these results continue to support the use of antibiotic bone cement and UV lights during TKA.展开更多
AlGaN-based ultraviolet light-emitting diodes(UV-LEDs) have attracted considerable interest due to their wide range of application fields. However, they are still suffering from low light out power and unsatisfactory ...AlGaN-based ultraviolet light-emitting diodes(UV-LEDs) have attracted considerable interest due to their wide range of application fields. However, they are still suffering from low light out power and unsatisfactory quantum efficiency.The utilization of polarization-doped technique by grading the Al content in p-type layer has demonstrated its effectiveness in improving LED performances by providing sufficiently high hole concentration. However, too large degree of grading through monotonously increasing the Al content causes strains in active regions, which constrains application of this technique, especially for short wavelength UV-LEDs. To further improve 340-nm UV-LED performances, segmentally graded Al content p-Al_xGa_(1-x)N has been proposed and investigated in this work. Numerical results show that the internal quantum efficiency and output power of proposed structures are improved due to the enhanced carrier concentrations and radiative recombination rate in multiple quantum wells, compared to those of the conventional UV-LED with a stationary Al content AlGaN electron blocking layer. Moreover, by adopting the segmentally graded p-Al_xGa_(1-x)N, band bending within the last quantum barrier/p-type layer interface is effectively eliminated.展开更多
The changes in total polyphenolics in elderberry (Sambucus nigra) following treatment with various doses of pulsed ultraviolet rays (UV) were investigated. Four pulsed UV durations (5, 10, 20, 30 seconds) at three ene...The changes in total polyphenolics in elderberry (Sambucus nigra) following treatment with various doses of pulsed ultraviolet rays (UV) were investigated. Four pulsed UV durations (5, 10, 20, 30 seconds) at three energy dosages (4500, 6000, 11,000 J/m2/pulse) were considered for the research. All treated elderberry fruits were incubated for 24 h at room temperature (25℃) following treatment to ensure enough response duration for enhanced development of polyphenols by the berries. The highest increase in total phenolics around 50% was found with 11,000 J/m2/pulse for a 10 seconds treatment while nearly 40% increase in total phenolics was found at an energy dosage of 11,000 J/m2/pulse after 5 seconds exposure. Even though most of the treatments indicated an increase in total polyphenols, some treatment expressed a decrease in phenolics content when compared to untreated fruits.展开更多
The conventional stationary Al content Al GaN electron blocking layer(EBL) in ultraviolet light-emitting diode(UV LED) is optimized by employing a linearly graded Al Ga N inserting layer which is 2.0 nm Al_(0.3) Ga_(0...The conventional stationary Al content Al GaN electron blocking layer(EBL) in ultraviolet light-emitting diode(UV LED) is optimized by employing a linearly graded Al Ga N inserting layer which is 2.0 nm Al_(0.3) Ga_(0.7) N/5.0 nm Alx Ga_(1-x) N/8.0 nm Al_(0.3) Ga_(0.7) N with decreasing value of x. The results indicate that the internal quantum efficiency is significantly improved and the efficiency droop is mitigated by using the proposed structure. These improvements are attributed to the increase of the effective barrier height for electrons and the reduction of the effective barrier height for holes,which result in an increased hole injection efficiency and a decreased electron leakage into the p-type region. In addition,the linearly graded AlGaN inserting layer can generate more holes in EBL due to the polarization-induced hole doping and a tunneling effect probably occurs to enhance the hole transportation to the active regions, which will be beneficial to the radiative recombination.展开更多
Uitraviolet（UV）light irradiation acting on human low density lipoprotein（LDL）couldgive rise to oxidative modification of LDL.Thiobarbituric acid reactive substances（TBARS）,rela-five electrophorefic mobility（REM...Uitraviolet（UV）light irradiation acting on human low density lipoprotein（LDL）couldgive rise to oxidative modification of LDL.Thiobarbituric acid reactive substances（TBARS）,rela-five electrophorefic mobility（REM）,relative fluorescence intensity at 420 nm（the excitation wavelength was 360nm）and lipid conjugated dienes of UV-irradiated LDL were all elevated withthe increase of irradiation time.Addition of 0.01％ EDTA into the irradiation system could inhi-bit this reaction,but the effect was not so potent as that induced in the Cu<sup>2+</sup>-PBS-LDLoxidative modification system China green tea polyphenols（CGTP）,on the other hand,had aneffective inhibitory effect with obvious dose-effect relationship.It was proposed that lipidperoxidation of LDL induced by free radicals which were generated from UV-irradiation andthe inhibitory effect of CGTP was attributed to its strong antioxidative action.展开更多
Benzophenone ultraviolet light filters(BPs)are high-production-volume chemicals extensively used in personal care products,leading to widespread human exposure.Given their estrogenic properties,the potential health ri...Benzophenone ultraviolet light filters(BPs)are high-production-volume chemicals extensively used in personal care products,leading to widespread human exposure.Given their estrogenic properties,the potential health risks associated with exposure to BPs have become a public health concern.This review aims to summarize sources and pathways of exposure to BPs and associated health risks.Dermal exposure,primarily through the use of sunscreens,constitutes a major pathway for BP exposure.At a recommended application rate,dermal exposure of BP-3 via the application of sunscreens may reach or exceed the suggested reference dose.Other exposure pathways to BPs,such as drinking water,seafood,and packaged foods,contribute minimal to the overall dose.Inhalation is a minor pathway of exposure;however,its contribution cannot be ignored.Human exposure to BPs is an order of magnitude higher in North America than in Asia and Europe.Studies conducted on laboratory animals and cells have consistently demonstrated the toxic effects of BP exposure.BPs are estrogenic and elicit reproductive and developmental toxicities.Furthermore,neurotoxicity,hepatotoxicity,nephrotoxicity,and carcinogenicity have been reported from chronic BP exposure.In addition to animal and cell studies,epidemiological investigations have identified associations between BPs and couples'fecundity and other reproductive disorders,as well as adverse birth outcomes.Further studies are urgently needed to understand the risks posed by BPs on human health.展开更多
We report the generation of quasi-cw vacuum ultraviolet(VUV)light at 160 nm with a repetition rate of 82 MHz by two second-harmonic generations and one sum frequency mixing.The VUV laser light is produced as a fifth-h...We report the generation of quasi-cw vacuum ultraviolet(VUV)light at 160 nm with a repetition rate of 82 MHz by two second-harmonic generations and one sum frequency mixing.The VUV laser light is produced as a fifth-harmonic generation of a mode-locked ps Ti:sapphire laser system by successive stages with nonlinear crystals of LBO and KBBF.A stable generation of laser light at 200 nm for more than 6 h is the most important step for obtaining the generation of light at a wavelength of 160 nm.展开更多
AIM:To evaluate the effect of different monochromatic lights on the refractive status and the secretion levels of neurotransmitters in the progressive myopic model of guinea pigs.METHODS:Guinea pigs(n=90)underwent dif...AIM:To evaluate the effect of different monochromatic lights on the refractive status and the secretion levels of neurotransmitters in the progressive myopic model of guinea pigs.METHODS:Guinea pigs(n=90)underwent different monochromatic lights irradiation for two weeks were randomly divided into 6 groups:white light(control),ultraviolet(UV),blue,green,red,and simulative sunlight(simSUN).The refractive status and axial length(AL)were measured.Transmission electron microscopy,Masson’s trichrome staining and hematoxylin-eosin staining were performed to observe the structural changes of retina and sclera.High-performance liquid chromatography(HPLC),western blotting and immunofluorescence were used to measure neurotransmitters and their receptors.RESULTS:Myopia models were established successfully.When compared the degrees of change in myopic eyes of control group,the UV group showed a minor decrease in AL and refraction,along with a significant increase in scleral thickness.In contrast,the red and green groups revealed a net increase in AL and refraction,coupled with a net decrease in scleral thickness(all,P<0.01).The dopamine concentration increased in the UV group,while concentrations of serotonin and melatonin significantly decreased(all,P<0.01).The groups that were exposed to UV,blue and simSUN,the expression of dopamine receptor D2(DRD2)increased,and the expression of hydroxytryptamine receptor 2A(HTR2A)and melatonin receptor type 2(MT2)decreased significantly when compared to the control group(all P<0.01).CONCLUSION:Exposure to short-wavelength light could slow the development of myopia by promoting the production of dopamine and suppressing the serotonin and melatonin concentration.The neurotransmitter receptors MT2,DRD2,and HTR2A in the sclera appear to play different roles by different color lights in myopic guinea pigs.展开更多
Wireless ultraviolet communication is a new type of communication mode. It refers to the transmission of information through the scattering of ultraviolet light by atmospheric particles and aerosol particles. The scat...Wireless ultraviolet communication is a new type of communication mode. It refers to the transmission of information through the scattering of ultraviolet light by atmospheric particles and aerosol particles. The scattering characteristics can enable the wireless ultraviolet communication system to transmit ultraviolet light signals in a non-line-of-sight manner, which overcomes the weakness that other free space optical communications must work in a line-of-sight manner. Based on the basic theory of scattering and absorption in atmospheric optics, taking the ultraviolet light with a wavelength of 266 nm as an example, this paper introduces the classical model of non-line-of-sight single-scattering coplanarity based on the ellipsoid coordinate system. The model is used to simulate and analyze the relationship between the geometric parameters such as transmission distance, transceiver elevation angle and transceiver half-angle and the received optical power per unit area. The performance of non-line-of-sight ultraviolet communication system in rain and fog environment is discussed respectively. The results show that the transmission quality of non-line-of-sight ultraviolet atmospheric propagation is greatly affected by the communication distance. As the distance increases, the received light power per unit area gradually decreases. In addition, increasing the emission elevation angle, the receiving elevation angle and the receiving half angle is an important way to improve the system performance.展开更多
Wide bandgap(3.37 eV)and high excitonbinding energy of ZnO(60 meV)make it a promising candidate for ultraviolet light-emitting diodes(LEDs)and low-threshold lasing diodes(LDs).However,the difficulty in producing stabl...Wide bandgap(3.37 eV)and high excitonbinding energy of ZnO(60 meV)make it a promising candidate for ultraviolet light-emitting diodes(LEDs)and low-threshold lasing diodes(LDs).However,the difficulty in producing stable and reproducible high-quality p-type ZnO has hindered the development of ZnO p–n homojunction LEDs.An alternative strategy for achieving ZnO electroluminescence is to fabricate heterojunction devices by employing other available p-type materials(such as p-GaN)or building new device structures.In this article,we will briefly review the recent progress in ZnO LEDs/LDs based on p–n heterostructures and metal–insulatorsemiconductor heterostructures.Some methods to improve device efficiency are also introduced in detail,including the introduction of Ag localized surface plasmons and single-crystalline nanowires into ZnO LEDs/LDs.展开更多
Storing reclaimed water in lakes is a widely used method of accommodating changes in the consumption of reclaimed water during wastewater reclamation and reuse. Solar light serves as an important function in degrading...Storing reclaimed water in lakes is a widely used method of accommodating changes in the consumption of reclaimed water during wastewater reclamation and reuse. Solar light serves as an important function in degrading pollutants during storage, and its effect on dissolved organic matter（DOM） was investigated in this study. Solar light significantly decreased the UV_（254） absorbance and fluorescence（FLU） intensity of reclaimed water.However, its effect on the dissolved organic carbon（DOC） value of reclaimed water was very limited. The decrease in the UV_（254） absorbance intensity and FLU excitation–emission matrix regional integration volume（FLU volume） of reclaimed water during solar light irradiation was fit with pseudo-first order reaction kinetics. The decrease of UV_（254） absorbance was much slower than that of the FLU volume. Ultraviolet light in solar light had a key role in decreasing the UV_（254） absorbance and FLU intensity during solar light irradiation. The light fluence-based removal kinetic constants of the UV_（254） and FLU intensity were independent of light intensity. The peaks of the UV_（254） absorbance and FLU intensity with an apparent molecular weight（AMW） of 100 Da to 2000 Da decreased after solar irradiation, whereas the DOC value of the major peaks did not significantly change.展开更多
The ultraviolet-visible light spectrophotometer method was adopted to determine thioglucoside in cabbage with the seeds.Individual plant of cabbage was used as test materials,palladium chloride as complexing agent and...The ultraviolet-visible light spectrophotometer method was adopted to determine thioglucoside in cabbage with the seeds.Individual plant of cabbage was used as test materials,palladium chloride as complexing agent and sodium cellulose glycolate as dispersing agent.The results showed that palladiumd thioglucoside method could be taken as a quick,easy and precise quantitative analysis method to determine thioglucoside in cabbage.展开更多
Tropospheric ozone （O3）, ultraviolet B （UVB） radiation and aerosol light scattering coefficients （SC） were investigated on a cruise ship during the fourth Chinese National Arctic Research Expedition from July 1 ...Tropospheric ozone （O3）, ultraviolet B （UVB） radiation and aerosol light scattering coefficients （SC） were investigated on a cruise ship during the fourth Chinese National Arctic Research Expedition from July 1 September 20, 2010. The results showed that O3, UVB and SC decreased with increasing latitude, with minimum values recorded in the central Arctic Ocean. Average O3 concentrations were 15.9 ppbv and 15.1 ppbv in the Bering Sea and Arctic Ocean, respectively. Ozone concentrations increased to 17.5 ppbv in the high Arctic region. Average UVB values were 0.26 W.m-2 and 0.14 W.m-2 in the Bering Sea and Arctic Ocean, respectively. The average SC in the Bering Sea was 4.3 M.m-1, more than twice the value measured in the Arctic Ocean, which had an average value of 1.7 M.m-1. Overall, UVB and SC values were stable in the central Arctic Ocean.展开更多
基金This project was supported by the National Natural Science Foundation of China(30500387)Natural Science Foundation of Jiangsu Province,China(BK2005008).
文摘This study examined the photostabilization of Azadirachtin-A （Aza-A） when exposed to ultraviolet light in the presence of some natural absorbers. Aza-A extract solutions with and without natural UV light absorbers in methanol were applied onto the surface of glass slides. At particular intervals, the remaining concentration of Aza-A was analyzed by HPLC. Using first-order kinetic equation, the dissipation half-life values （DT^0） for the degradation of Aza-A under ultraviolet radiation were obtained. It indicated that the addition of ferulic acid, gallic acid, and rutin provided moderate degree of photostabilization of Aza-A and that addition of aloin provided the best photostabilization of Aza-A, among these UV absorbers studied. Photostabilization of Aza-A by different UV light absorbers appears to be due to the competitive energy absorption of UV photons by the absorbers molecules. The dissipation half-life values of Aza-A after irradiation under ultraviolet light suggested that the addition of aloin （in 1 ： 1 mol ratio） can provide better photostabilization of azadirachtin molecule.
基金Supported by Research to Prevent Blindness,New York,NY,USA。
文摘AIM:To determine the amount of ultraviolet(UV)light irradiance that various layers of the eye receive as sunlight passes through the eye,and to investigate the protective benefits of UV light-blocking contact lenses.METHODS:Twenty-four porcine eyes were prepared in one of three ways:isolated cornea,cornea and lens together,or whole eye preparation.UV light irradiance was measured with a UV-A/B light meter before and after the eye preparations were placed over the meter to measure UV light penetration in each eye structure.In the whole eye preparation,a hole was placed in the fovea to measure light as it passed through the vitreous.Subsequently,UVprotective contact lenses were placed over the structures,and UV light penetrance was measured.Measurements of UV light exposure were taken outdoors at various locations and times.RESULTS:Cornea absorbed 63.56%of UV light that reached the eye.Cornea and lens absorbed 99.34%of UV light.Whole eye absorbed 99.77%of UV light.When UV-protective contact lenses were placed,absorption was 98.90%,99.55%,and 99.87%,respectively.UV light exposure was dependent on directionality and time of day,and was greatest in areas of high albedo that reflect significant amounts of light,such as a beach.CONCLUSION:Cornea absorbs the majority of UV light that reaches the eye in this model.UV-protective contact lenses reduce UV exposure to the eye.Locations with high albedo expose the eye to higher levels of UV light.
基金Project supported by the Special Strategic Emerging Industries of Guangdong Province,China(Grant No.2012A080304006)the Major Scientific and Technological Projects of Zhongshan City,Guangdong Province,China(Grant No.2014A2FC204)the Forefront of Technology Innovation and Key Technology Projects of Guangdong Province,China(Grant Nos.2014B010121001 and 2014B010119004)
文摘The AlGaN-based deep ultraviolet light-emitting diodes（LED） with double electron blocking layers（d-EBLs） on both sides of the active region are investigated theoretically. They possess many excellent performances compared with the conventional structure with only a single electron blocking layer, such as a higher recombination rate, improved light output power and internal quantum efficiency（IQE）. The reasons can be concluded as follows. On the one hand, the weakened electrostatic field within the quantum wells（QWs） enhances the electron–hole spatial overlap in QWs, and therefore increases the probability of radioactive recombination. On the other hand, the added n-AlGaN layer can not only prevent holes from overflowing into the n-side region but also act as another electron source, providing more electrons.
基金supported by the National Natural Science Foundation of China(51901086)Natural Science Foundation of Jiangsu Province of China(BK20190977).
文摘The influence of ultraviolet light irradiation on the pitting corrosion performance of a Zr_(2)Ni metallic glass was examined using electrochemical methods and immersion test in 0.05 mol/L NaCl solution.From the results of potentiostatic polarization,the pitting potential of the ultraviolet light-irradiated sample shifted positively with a value of~300 mV,revealing the enhanced pitting corrosion resistance of the samples.The corrosion morphology after the immersion test also demonstrated lower degree of corrosion damage and improved pitting resistance of the sample with ultraviolet light irradiation.X-ray photoelectron spectroscopy analysis revealed more zirconium enrichment in the passive film and no chloride ions adsorption for the samples with ultraviolet irradiation,accounting for the suppression of the pit generation and growth.Our findings indicate that ultraviolet light irradiation improves the pitting corrosion resistance of the Zr-based metallic glasses,which are promising structural materials to be used in corrosion environments with high ultraviolet irradiation.
基金Project supported by the National Natural Science Foundation for Distinguished Young Scholars of China(Grant No.61425021)the Natural Natural Science Foundation of China(Grant Nos.11374296,61376054,61475153,and 61604132)
文摘Deep-ultraviolet（DUV） light-emitting devices（LEDs） have a variety of potential applications.Zinc-oxide-based materials,which have wide bandgap and large exciton binding energy,have potential applications in high-performance DUV LEDs.To realize such optoelectronic devices,the modulation of the bandgap is required.This has been demonstrated by the developments of Mg_xZn_（1-x）O and Be_xZn_（1-x）O alloys for the larger bandgap materials.Many efforts have been made to obtain DUV LEDs,and promising successes have been achieved continuously.In this article,we review the recent progress of and problems encountered in the research of ZnO-based DUV LEDs.
文摘Objective: The purpose of this study was to determine usefulness of antibiotic bone cement and UV light in primary Total Knee Arthroplasty (TKA). Patients and Methods: Between 1986 and 2008, 3105 TKAs were performed using 750 mg of cefuroxime per bag of cement (Group 1), 7537 using cefuroxime and UV light (Group 2), and 4573 using UV light and gentamicin premixed (Group 3). Results: The primary infection rate was 0.57% (87 acute postoperative infections). Of these, 27 (0.9%) were in Group 1, 44 (0.6%) were in Group 2, and 16 (0.35%) were in Group 3 (p = 0.0013). Kaplan-Meier survival in Groups 1 - 3 for reoperation for aseptic loosening of any component at 5 years was 0.9908, 0.9927, and 0.9959, respectively (p = 0.1315). Conclusion: Despite potential concerns mentioned in the literature, these results continue to support the use of antibiotic bone cement and UV lights during TKA.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61874161 and 11474105)the Science and Technology Program of Guangdong Province,China(Grant Nos.2017B010127001 and 2015B010105011)+4 种基金the Education Department Project of Guangdong Province,China(Grant No.2017KZDXM022)the Science and Technology Project of Guangzhou City,China(Grant No.201607010246)the Program for Changjiang Scholars and Innovative Research Team in Universities of China(Grant No.IRT13064)the Science and Technology Project of Shenzhen City,China(Grant No.GJHZ20180416164721073)the Science and Technology Planning of Guangdong Province,China(Grant No.2015B010112002)
文摘AlGaN-based ultraviolet light-emitting diodes(UV-LEDs) have attracted considerable interest due to their wide range of application fields. However, they are still suffering from low light out power and unsatisfactory quantum efficiency.The utilization of polarization-doped technique by grading the Al content in p-type layer has demonstrated its effectiveness in improving LED performances by providing sufficiently high hole concentration. However, too large degree of grading through monotonously increasing the Al content causes strains in active regions, which constrains application of this technique, especially for short wavelength UV-LEDs. To further improve 340-nm UV-LED performances, segmentally graded Al content p-Al_xGa_(1-x)N has been proposed and investigated in this work. Numerical results show that the internal quantum efficiency and output power of proposed structures are improved due to the enhanced carrier concentrations and radiative recombination rate in multiple quantum wells, compared to those of the conventional UV-LED with a stationary Al content AlGaN electron blocking layer. Moreover, by adopting the segmentally graded p-Al_xGa_(1-x)N, band bending within the last quantum barrier/p-type layer interface is effectively eliminated.
文摘The changes in total polyphenolics in elderberry (Sambucus nigra) following treatment with various doses of pulsed ultraviolet rays (UV) were investigated. Four pulsed UV durations (5, 10, 20, 30 seconds) at three energy dosages (4500, 6000, 11,000 J/m2/pulse) were considered for the research. All treated elderberry fruits were incubated for 24 h at room temperature (25℃) following treatment to ensure enough response duration for enhanced development of polyphenols by the berries. The highest increase in total phenolics around 50% was found with 11,000 J/m2/pulse for a 10 seconds treatment while nearly 40% increase in total phenolics was found at an energy dosage of 11,000 J/m2/pulse after 5 seconds exposure. Even though most of the treatments indicated an increase in total polyphenols, some treatment expressed a decrease in phenolics content when compared to untreated fruits.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61874161 and 11474105)the Science and Technology Program of Guangdong Province,China(Grant No.2017B010127001)+1 种基金the Science and Technology of Shenzhen City,China(Grant No.GJHZ20180416164721073)the Education Department Funding of Guangdong Province,China(Grant No.2017KZDXM022)
文摘The conventional stationary Al content Al GaN electron blocking layer(EBL) in ultraviolet light-emitting diode(UV LED) is optimized by employing a linearly graded Al Ga N inserting layer which is 2.0 nm Al_(0.3) Ga_(0.7) N/5.0 nm Alx Ga_(1-x) N/8.0 nm Al_(0.3) Ga_(0.7) N with decreasing value of x. The results indicate that the internal quantum efficiency is significantly improved and the efficiency droop is mitigated by using the proposed structure. These improvements are attributed to the increase of the effective barrier height for electrons and the reduction of the effective barrier height for holes,which result in an increased hole injection efficiency and a decreased electron leakage into the p-type region. In addition,the linearly graded AlGaN inserting layer can generate more holes in EBL due to the polarization-induced hole doping and a tunneling effect probably occurs to enhance the hole transportation to the active regions, which will be beneficial to the radiative recombination.
基金The project was supported by the National Natural Science Foundation of China No 39070270
文摘Uitraviolet（UV）light irradiation acting on human low density lipoprotein（LDL）couldgive rise to oxidative modification of LDL.Thiobarbituric acid reactive substances（TBARS）,rela-five electrophorefic mobility（REM）,relative fluorescence intensity at 420 nm（the excitation wavelength was 360nm）and lipid conjugated dienes of UV-irradiated LDL were all elevated withthe increase of irradiation time.Addition of 0.01％ EDTA into the irradiation system could inhi-bit this reaction,but the effect was not so potent as that induced in the Cu<sup>2+</sup>-PBS-LDLoxidative modification system China green tea polyphenols（CGTP）,on the other hand,had aneffective inhibitory effect with obvious dose-effect relationship.It was proposed that lipidperoxidation of LDL induced by free radicals which were generated from UV-irradiation andthe inhibitory effect of CGTP was attributed to its strong antioxidative action.
基金supported by the Natural Science Foundation of China(No.22022612,and No.21677184)Natural Science Foundation of Guangdong Province,China(No.2020A0104006 and No.2021A1515010243)+1 种基金the Fundamental Research Funds for the Central Universitiessupported,in part,by the National Institute of Environmental Health Sciences(NIEHS)under award number U2CES026542(KK).
文摘Benzophenone ultraviolet light filters(BPs)are high-production-volume chemicals extensively used in personal care products,leading to widespread human exposure.Given their estrogenic properties,the potential health risks associated with exposure to BPs have become a public health concern.This review aims to summarize sources and pathways of exposure to BPs and associated health risks.Dermal exposure,primarily through the use of sunscreens,constitutes a major pathway for BP exposure.At a recommended application rate,dermal exposure of BP-3 via the application of sunscreens may reach or exceed the suggested reference dose.Other exposure pathways to BPs,such as drinking water,seafood,and packaged foods,contribute minimal to the overall dose.Inhalation is a minor pathway of exposure;however,its contribution cannot be ignored.Human exposure to BPs is an order of magnitude higher in North America than in Asia and Europe.Studies conducted on laboratory animals and cells have consistently demonstrated the toxic effects of BP exposure.BPs are estrogenic and elicit reproductive and developmental toxicities.Furthermore,neurotoxicity,hepatotoxicity,nephrotoxicity,and carcinogenicity have been reported from chronic BP exposure.In addition to animal and cell studies,epidemiological investigations have identified associations between BPs and couples'fecundity and other reproductive disorders,as well as adverse birth outcomes.Further studies are urgently needed to understand the risks posed by BPs on human health.
文摘We report the generation of quasi-cw vacuum ultraviolet(VUV)light at 160 nm with a repetition rate of 82 MHz by two second-harmonic generations and one sum frequency mixing.The VUV laser light is produced as a fifth-harmonic generation of a mode-locked ps Ti:sapphire laser system by successive stages with nonlinear crystals of LBO and KBBF.A stable generation of laser light at 200 nm for more than 6 h is the most important step for obtaining the generation of light at a wavelength of 160 nm.
基金Supported by the Zhejiang Traditional Chinese Medicine Science and Technology Plan(No.2023ZL241)Zhejiang Medical Science and Technology Plan(No.2025KY648).
文摘AIM:To evaluate the effect of different monochromatic lights on the refractive status and the secretion levels of neurotransmitters in the progressive myopic model of guinea pigs.METHODS:Guinea pigs(n=90)underwent different monochromatic lights irradiation for two weeks were randomly divided into 6 groups:white light(control),ultraviolet(UV),blue,green,red,and simulative sunlight(simSUN).The refractive status and axial length(AL)were measured.Transmission electron microscopy,Masson’s trichrome staining and hematoxylin-eosin staining were performed to observe the structural changes of retina and sclera.High-performance liquid chromatography(HPLC),western blotting and immunofluorescence were used to measure neurotransmitters and their receptors.RESULTS:Myopia models were established successfully.When compared the degrees of change in myopic eyes of control group,the UV group showed a minor decrease in AL and refraction,along with a significant increase in scleral thickness.In contrast,the red and green groups revealed a net increase in AL and refraction,coupled with a net decrease in scleral thickness(all,P<0.01).The dopamine concentration increased in the UV group,while concentrations of serotonin and melatonin significantly decreased(all,P<0.01).The groups that were exposed to UV,blue and simSUN,the expression of dopamine receptor D2(DRD2)increased,and the expression of hydroxytryptamine receptor 2A(HTR2A)and melatonin receptor type 2(MT2)decreased significantly when compared to the control group(all P<0.01).CONCLUSION:Exposure to short-wavelength light could slow the development of myopia by promoting the production of dopamine and suppressing the serotonin and melatonin concentration.The neurotransmitter receptors MT2,DRD2,and HTR2A in the sclera appear to play different roles by different color lights in myopic guinea pigs.
文摘Wireless ultraviolet communication is a new type of communication mode. It refers to the transmission of information through the scattering of ultraviolet light by atmospheric particles and aerosol particles. The scattering characteristics can enable the wireless ultraviolet communication system to transmit ultraviolet light signals in a non-line-of-sight manner, which overcomes the weakness that other free space optical communications must work in a line-of-sight manner. Based on the basic theory of scattering and absorption in atmospheric optics, taking the ultraviolet light with a wavelength of 266 nm as an example, this paper introduces the classical model of non-line-of-sight single-scattering coplanarity based on the ellipsoid coordinate system. The model is used to simulate and analyze the relationship between the geometric parameters such as transmission distance, transceiver elevation angle and transceiver half-angle and the received optical power per unit area. The performance of non-line-of-sight ultraviolet communication system in rain and fog environment is discussed respectively. The results show that the transmission quality of non-line-of-sight ultraviolet atmospheric propagation is greatly affected by the communication distance. As the distance increases, the received light power per unit area gradually decreases. In addition, increasing the emission elevation angle, the receiving elevation angle and the receiving half angle is an important way to improve the system performance.
基金supported by the National Basic Research Program of China(2012CB933703)the National High Technology Research and Development Program of China(2006AA03Z311)+1 种基金the National Natural Science Foundation of China(51172041,91233204 and 51372035)the Program for New Century Excellent Talents in University(NCET-11-0615)
文摘Wide bandgap(3.37 eV)and high excitonbinding energy of ZnO(60 meV)make it a promising candidate for ultraviolet light-emitting diodes(LEDs)and low-threshold lasing diodes(LDs).However,the difficulty in producing stable and reproducible high-quality p-type ZnO has hindered the development of ZnO p–n homojunction LEDs.An alternative strategy for achieving ZnO electroluminescence is to fabricate heterojunction devices by employing other available p-type materials(such as p-GaN)or building new device structures.In this article,we will briefly review the recent progress in ZnO LEDs/LDs based on p–n heterostructures and metal–insulatorsemiconductor heterostructures.Some methods to improve device efficiency are also introduced in detail,including the introduction of Ag localized surface plasmons and single-crystalline nanowires into ZnO LEDs/LDs.
基金funded by the National Science Fund of China (Nos. 51138006, 51290284)the National High-Tech R&D Program (863) of China (No. 2013AA065205)+1 种基金the Key Science and Technology Project of Shenzhen Water AuthorityThe Collaborative Innovation Center for Regional Environmental Quality also supported this research
文摘Storing reclaimed water in lakes is a widely used method of accommodating changes in the consumption of reclaimed water during wastewater reclamation and reuse. Solar light serves as an important function in degrading pollutants during storage, and its effect on dissolved organic matter（DOM） was investigated in this study. Solar light significantly decreased the UV_（254） absorbance and fluorescence（FLU） intensity of reclaimed water.However, its effect on the dissolved organic carbon（DOC） value of reclaimed water was very limited. The decrease in the UV_（254） absorbance intensity and FLU excitation–emission matrix regional integration volume（FLU volume） of reclaimed water during solar light irradiation was fit with pseudo-first order reaction kinetics. The decrease of UV_（254） absorbance was much slower than that of the FLU volume. Ultraviolet light in solar light had a key role in decreasing the UV_（254） absorbance and FLU intensity during solar light irradiation. The light fluence-based removal kinetic constants of the UV_（254） and FLU intensity were independent of light intensity. The peaks of the UV_（254） absorbance and FLU intensity with an apparent molecular weight（AMW） of 100 Da to 2000 Da decreased after solar irradiation, whereas the DOC value of the major peaks did not significantly change.
文摘The ultraviolet-visible light spectrophotometer method was adopted to determine thioglucoside in cabbage with the seeds.Individual plant of cabbage was used as test materials,palladium chloride as complexing agent and sodium cellulose glycolate as dispersing agent.The results showed that palladiumd thioglucoside method could be taken as a quick,easy and precise quantitative analysis method to determine thioglucoside in cabbage.
基金supported by the project"Fourth Chinese National Arctic Research Expedition"
文摘Tropospheric ozone （O3）, ultraviolet B （UVB） radiation and aerosol light scattering coefficients （SC） were investigated on a cruise ship during the fourth Chinese National Arctic Research Expedition from July 1 September 20, 2010. The results showed that O3, UVB and SC decreased with increasing latitude, with minimum values recorded in the central Arctic Ocean. Average O3 concentrations were 15.9 ppbv and 15.1 ppbv in the Bering Sea and Arctic Ocean, respectively. Ozone concentrations increased to 17.5 ppbv in the high Arctic region. Average UVB values were 0.26 W.m-2 and 0.14 W.m-2 in the Bering Sea and Arctic Ocean, respectively. The average SC in the Bering Sea was 4.3 M.m-1, more than twice the value measured in the Arctic Ocean, which had an average value of 1.7 M.m-1. Overall, UVB and SC values were stable in the central Arctic Ocean.
