The effect of changing Be doping concentration in GaAs layer on the integrated photosensitivity for nega- tive-electron-affinity GaAs photocathodes is investigated. Two GaAs samples with the monolayer structure and th...The effect of changing Be doping concentration in GaAs layer on the integrated photosensitivity for nega- tive-electron-affinity GaAs photocathodes is investigated. Two GaAs samples with the monolayer structure and the muhilayer structure are grown by molecular beam epitaxy. The former has a constant Be concentration of 1 × 10^19 cm^-3, while the latter includes four layers with Be doping concentrations of 1 × 10^19, 7 × 10^18, 4 × 10^18, and 1 × 10^18 cm^-3 from the bottom to the surface. Negative-electron-affinity GaAs photocathodes are fabricated by exciting the sample surfaces with alternating input of Cs and O in the high vacuum system. The spectral response results measured by the on-line spectral response measurement system show that the integrated photosensitivity of the photocathode with the muhilayer structure enhanced by at least 50% as compared to that of the monolayer structure. This attributes to the improvement in the crystal quality and the increase in the surface escape probability. Different stress situations are observed on GaAs samples with monolayer structure and muhilayer structure, respectively.展开更多
The title polymers PMS 8Pz,M=Mn Ⅱ,Fe Ⅱ,Co Ⅱ,Ni Ⅱ,Cu Ⅱ,Zn Ⅱ,were synthesized by teaction of 2,3,5,6 tetracyano 1,4 dithiin with corresponding metal salts ,respectively.The styucture and properties of th...The title polymers PMS 8Pz,M=Mn Ⅱ,Fe Ⅱ,Co Ⅱ,Ni Ⅱ,Cu Ⅱ,Zn Ⅱ,were synthesized by teaction of 2,3,5,6 tetracyano 1,4 dithiin with corresponding metal salts ,respectively.The styucture and properties of these polyers were characterized by elemental analysis,transmission electron microscope,DTA,IR, UV Vis,fluorescence and EPR spectra. It has been found that these conjugated polymers have the property of intrinsic semiconductor. The conductivity σ 298K of these polymers is in the range of 10 -9 ￣10 -3 S · cm -1 under pressure 10.63 MPa and incremental in the metal orderMn < Co<Fe<Zn<Cu<Ni.\ The photosensitivity of the MS 8Pz to the CdS PVA films is incremental in the metal order Zn < Mn < Co < Fe < Cu < Ni.展开更多
Polymer thin-film transistors （PTFTs） based on poly（3-hexylthiophene） are fabricated by the spin-coating process, and their photo-sensing characteristics are investigated under steady-state visible-light illuminat...Polymer thin-film transistors （PTFTs） based on poly（3-hexylthiophene） are fabricated by the spin-coating process, and their photo-sensing characteristics are investigated under steady-state visible-light illumination. The photosensitivity of the device is strongly modulated by gate voltage under various illuminations. When the device is in the subthreshold operating mode, a significant increase in its drain current is observed with a maximum photosensitivity of 1.7×10^3 at an illumination intensity of 1200 lx, and even with a relatively high photosensitivity of 611 at a low illumination intensity of 100 lx. However, when the device is in the on-state operating mode, the photosensitivity is very low： only 1.88 at an illumination intensity of 1200 lx for a gate voltage of -20 V and a drain voltage of -20 V. The results indicate that the devices could be used as photo-detectors or sensors in the range of visible light. The modulation mechanism of the photosensitivity in the PTFT is discussed in detail.展开更多
The present study examined a patient with traumatic brain injury who exhibited visual photosensitivity and axonal iniury of the left optic radiation, which was detected by diftusion tensor imaging. The patient was a 4...The present study examined a patient with traumatic brain injury who exhibited visual photosensitivity and axonal iniury of the left optic radiation, which was detected by diftusion tensor imaging. The patient was a 41-year-old man. He began to complain of photosensitivity at 4 months after head trauma. Ophthalmic evaluation, including visual-evoked potential and conventional brain magnetic resonance imaging, did not reveal a pathologic basis for photosensitivity. Axonal injury in the left optic radiation was detected via diffusion tensor imaging at 36 months after head trauma. The lesion was almost recovered at 76 months. However, photosensitivity continued. Therefore, the photosensitivity was considered to be a result of axonal injury to the left optic radiation, which could be a symptom of maladaptive plasticity that occurs during recovery of axonal injury of the left optic radiation.展开更多
We report a novel technique to enhance the ultraviolet （UV） photosensitivity of a ZnO nanosensor with ZnO nanowires bridged on micromachined metallic electrodes. The experimental results reveal that the photoconduct...We report a novel technique to enhance the ultraviolet （UV） photosensitivity of a ZnO nanosensor with ZnO nanowires bridged on micromachined metallic electrodes. The experimental results reveal that the photoconductivity and the time response of the ZnO nanowire sensor with either Schottky or Ohmic contacts are significantly improved by electrifying the nanowire sensors using an alternating current at the frequency of megahertz. An integrated UV sensor incorporating ZnO nanowires with a constant current mode driving circuit is developed, which demonstrates promising sensitivity and time response to UV illumination with a low power consumption.展开更多
The polymerization of methyl acrylate was sensitive to UV light. Under UV light,the rate of polymerization is 8 times as high as the rate in dark.The overall activation energy was decreased by the UV light (313nm).A t...The polymerization of methyl acrylate was sensitive to UV light. Under UV light,the rate of polymerization is 8 times as high as the rate in dark.The overall activation energy was decreased by the UV light (313nm).A tentative explanation is given and the mechanism is discussed.展开更多
The influences of UV light irradiation (313 nm) and diffused daylight on the polymerization of methyl acrylate initiated by the ceric ammonium nitrate without any reducing agent have been studied both in aqueous nitri...The influences of UV light irradiation (313 nm) and diffused daylight on the polymerization of methyl acrylate initiated by the ceric ammonium nitrate without any reducing agent have been studied both in aqueous nitric acid and in pure water. The rate of polymerization was found to be accelerated and the overall activation energy and the induction time were found to be decreased sharply by the UV light irradiation. Under UV light, the rate of polymerization is 8 times as high as the rate in dark. The rate of polymerization was found to attain a maximum with the increase of nitric acid concentration and the rate of polymerization became less sensitive to UV light in the presence of nitric acid whereas the induction period reduced outstandingly. Based on the experimental results, the mechanism is proposed.展开更多
Polymerization of acrylamide initiated by ceric ammonium nitrate alone has been studied in aqueous medium. The effects of UV light irradiation on the initial rates of polymerization, the activation energy and on the p...Polymerization of acrylamide initiated by ceric ammonium nitrate alone has been studied in aqueous medium. The effects of UV light irradiation on the initial rates of polymerization, the activation energy and on the polymer molecular weights have been investigated. Compared with that in the dark, the rate of polymerization under UV light was accelerated to eleven times higher, and the overall activation energy was lowered markedly.展开更多
Background: Autoantibodies (Aabs) are the hallmark of numerous systemic autoimmune pathologies (SAPs), for instance anti-Ro/SS-A Aabs are usually found in Systemic Lupus Erythematosus (SLE) and Sjogren’s Syndrome. Cu...Background: Autoantibodies (Aabs) are the hallmark of numerous systemic autoimmune pathologies (SAPs), for instance anti-Ro/SS-A Aabs are usually found in Systemic Lupus Erythematosus (SLE) and Sjogren’s Syndrome. Cutaneous photosensitivity (CP) is found in most forms and subsets of LE and consists of a skin rash as a result of unusual reaction to sunlight. There are many theories which relate specifically the presence of circulating anti-Ro/SS-A Aabs with the CP phenomenon, though there are several studies which are in disagreement. Results: In this study we analyzed the relationship between CP and anti-Ro Aabs by means of two approaches. The first one included an in vitro model where we evaluated by flow cytometry the binding capacity of affinity-purified Aabs to autoantigens relocalized on apoptotic keratinocyte’s surface. We found that there was no relationship between the binding capacity of serum from 10 selected patients or their corresponding purified anti-Ro52 and anti-Ro60 Aabs, and the presence or absence of CP, neither with the SAPs. The in vivo model consisted of Hairless SKH:1 mice which were induced to produce anti-murine Ro52 and/or Ro60 Aabs and were subsequently irradiated with UVB light. We evaluated the skin histology and also the epidermal production of TNF-α. We found no differences between the groups in neither of the parameters evaluated. Conclusions: These results agree with some studies on the role of the Aabs in CP, considering anti-Ro Aabs not as the only responsible for the manifestation;and disagree with many other authors, who believe in the strong association between these two events.展开更多
New water soluble and photocrosslinkable prepolymers containing acrylate and quaternary ammonium salt groups were synthesized from epoxy phenolic resin via ring-opening reaction with acrylic acid and with aqueous solu...New water soluble and photocrosslinkable prepolymers containing acrylate and quaternary ammonium salt groups were synthesized from epoxy phenolic resin via ring-opening reaction with acrylic acid and with aqueous solution of triethylamine hydrochloride successively. The second reaction needs no phase transfer catalyst to accelerate, since the product formed can act as a phase transfer catalyst. The prepolymer obtained contains both photocrosslinkable acrylate groups and hydrophilic quaternary ammonium salt groups. Optimum conditions for these reactions were studied. The photosensitivity of the prepolymer was also investigated. The effects of different photoinitiators, different crosslinkable diluent monomers and amine accelerator on the photosensitivity of the prepolymer were compared. The photoinitiator of hydrogen abstraction type is still effective without using amine or alcohol as accelerator, because the prepolymer contains a H beside the OH groups formed in the ring-opening reactions.展开更多
Dissolved organic matter(DOM)from each treatment process of wastewater treatment plants(WWTPs)contains abundant photosensitive substances,which could significantly affect the photodegradation of 17α-ethinylestradiol(...Dissolved organic matter(DOM)from each treatment process of wastewater treatment plants(WWTPs)contains abundant photosensitive substances,which could significantly affect the photodegradation of 17α-ethinylestradiol(EE2).Nevertheless,information about EE2 photodegradation behavior mediated by DOM from diverse WWTPs and the photosensitivity sources of such DOM are inadequate.This study explored the photodegradation behavior of EE2 mediated by four typical WWTPs’DOM solutions and investigated the photosensitivity sources of DOM in the anaerobic-anoxic-oxic(A2/O)process.The parallel factor analysis identified three varying fluorescing components of these DOM,tryptophan-like substances or protein-like substances,microbial humuslike substances,and humic-like components.The photodegradation rate constants of EE2 were positively associated with the humification degree of DOM(P<0.05).The triplet state substances were responsible for the degradation of EE2.DOM extracted from the A2/O process,especially in the secondary treatment process had the fastest EE2 photodegradation rate compared to that of the other three processes.Four types of components(water-soluble organic matter(WSOM),extracellular polymeric substance,humic acid,and fulvic acid)were separated from the A2/O process DOM.WSOM had the highest promotion effect on EE2 photodegradation.Fulvic acid-like components and humic acid-like organic compounds in WSOM were speculated to be important photosensitivity substances that can generate triplet state substances.This research explored the physicochemical properties and photosensitive sources of DOM in WWTPs,and explained the fate of estrogens photodegradation in natural waters.展开更多
Background Electroencephalogram （EEG） activity in normal subjects and epileptic patients is often closely related to the eye＇s status such as eye opened （EO）, eye closure （ECL） and eyes closed （EC）. ECL is th...Background Electroencephalogram （EEG） activity in normal subjects and epileptic patients is often closely related to the eye＇s status such as eye opened （EO）, eye closure （ECL） and eyes closed （EC）. ECL is the period immediately after closing of the eyes and only lasts for less than 3 seconds if the eyes remain closed. EC is the period as long as the eyes are closed. Epileptiform changes on EEG induced by ECL or EC are called the changes of ECL sensitivity （ECLS） or EC sensitivity （ECS）. ECLS occurs mainly but not exclusively in photosensitive patients and ECS has been seen rarely in photosensitive patients. This study aimed to investigate the relationships among ECLS, ECS, photosensitivity and epilepsy syndromes in children. Methods EEG records from child patients in the EEG Department of Peking University First Hospital during the period of May 2005 to May 2007 were examined for the presence of ECLS or ECS. Open-close eye tests and intermittent photic stimulations were carried out during video-EEG monitoring for examining ECLS, ECS and photosensitivity. Results Based on ECLS and ECS on their EEGs, 30 patients were divided into ECLS group （16 cases） and ECS group （14 cases）. There were more boys than girls in the two groups. The mean age of initial detection of ECLS and ECS was 10 years, and the average onset age of seizures was 9 years. The epilepsy syndromes in the ECLS group included idiopathic photosensitive occipital lobe epilepsy, Panayiotopoulos syndrome, symptomatic occipital lobe epilepsy, juvenile myoclonic epilepsy, juvenile absence epilepsy, eyelid myoclonia with absences, epilepsy with grand mal on awakening and pure photosensitive epilepsy with mainly generalized tonic clonic seizures. Those in the ECS group were juvenile myoclonic epilepsy, idiopathic photosensitive occipital lobe epilepsy, Panayiotopoulos syndrome and Gastaut type-idiopathic children occipital epilepsy. Photosensitivity was detected in 88% of patients with ECLS and 29% of patients with ECS. Conclusions ECLS and ECS are relatively common in females. Comparing with ECS, ECLS is found in more epilepsy syndromes. However, ECS and ECLS could exist in the same epilepsy syndrome. ECLS and ECS can be associated or dissociated with photosensitivity. The rate of ECLS with photosensitivity is higher than that of ECS with photosensitivity, suggesting that mechanisms for ECLS, ECS and photosensitivity may be different but correlated.展开更多
Currently three major problems seriously limit the practical application of can-cer photodynamic therapy(PDT):(i)the hypoxic tumor microenvironment(TME);(ii)low generation efficiency of toxic reactive oxygen species(RO...Currently three major problems seriously limit the practical application of can-cer photodynamic therapy(PDT):(i)the hypoxic tumor microenvironment(TME);(ii)low generation efficiency of toxic reactive oxygen species(ROS)in aggre-gates and(iii)shallow tissue penetration depth of excitation light.Very limited approaches are available for addressing all the above three problems with a single design.Herein,a rational“three birds with one stone”molecular and nanoengi-neering strategy is demonstrated:a photodynamic nanoplatform U-Ir@PAA-ABS based on the covalent combination of lanthanide-doped upconversion nanoparti-cles(UCNPs)and an AIE-active dinuclear Ir(III)complex provides a low oxygen concentration-dependent type-I photochemical process upon 980 nm irradiation by Föster resonance energy transfer(FRET).U-Ir@PAA-ABS targets mitochondria and has excellent phototoxicity even in severe hypoxia environments upon 980 nm irradiation,inducing a dual-mode cell death mechanism by apoptosis and ferropto-sis.Taken together,the in vitro and in vivo results demonstrate a successful strategy for improving the efficacy of PDT against hypoxic tumors.展开更多
Antibacterial agent of activatable photosensitizer not only has the advantages of traditional photosensitizers,such as good curative effect and low resistance,but also has better selectivity for bacteria and lower tox...Antibacterial agent of activatable photosensitizer not only has the advantages of traditional photosensitizers,such as good curative effect and low resistance,but also has better selectivity for bacteria and lower toxicity to normal tissues.Limited reports of activatable photosensitizer can be used to treat drugresistant bacteria.In order to meet this challenge,we designed and synthesized an activatable photosensitizer(Ce-OHOA),which can not only selectively identify methicillin-resistant Staphylococcus aureus(MRSA)with high expression ofβ-lactamase by fluorescence imaging,but also kill MRSA with less than10 times the concentration and 10 times the irradiation dose of CySG-2 reported.Ce-OHOA not only combines the dual functions of fluorescence diagnosis and photodynamic therapy,but also selectively acts on bacteria with high expression ofβ-lactamase and has little toxicity to normal cells.We expect that the study of this activating photosensitizer will provide a new solution for antibacterial photodynamic therapy(aPDT)of drug-resistant bacteria.展开更多
Aggregate-level photodynamic therapy(PDT)has attracted significant interest and driven substantial advances in multifunction phototheranostic platforms.As exem-plified by two typical instances of aggregation-caused quen...Aggregate-level photodynamic therapy(PDT)has attracted significant interest and driven substantial advances in multifunction phototheranostic platforms.As exem-plified by two typical instances of aggregation-caused quenching of reactive oxygen species(ROS)and aggregation-induced generation of ROS,the aggregation effect plays a significant role on the ROS generation of photosensitizers(PSs),which is worthy of in-depth exploration and full utilization.However,in contrast to the well-developed researches on the aggregation effect on luminescence,the studies concerning the aggregation effect on ROS generation are currently in a relatively nascent and disjointed stage,lacking guidance from afirmly established research paradigm.To advance this regard,this review aims at providing a consolidated overview of the fundamental principles and research status of aggregation effects on the ROS generation.Here,the research status can be organized into two main facets.One involves the comparison between isolated state and aggregated state,which is mainly conducted by two methods of changing solvent environments and adding adjuvants into a given solvent.The other underscores the distinctions between different aggregate states,consisting of three parts,namely comparison within the same or between different categories based on the classification of single-component and multicomponent aggregates.In this endeavor,we will present our views on cur-rent research methodologies that explore how aggregation affects ROS generation and highlight the design strategies to leverage the aggregation effect to optimize PS regiments.We aspire this review to propel the advancement of phototheranostic plat-forms and accelerate the clinical implementation of precision medicine,and inspire more contributions to aggregate-level photophysics and photochemistry,pushing the aggregate science and materials forward.展开更多
Efficient strategies for transforming Bacillus subtilis vegetative cells into spores(BtS transformation)are still limited,although they show promise for the treatment of inflammatory bowel disease(IBD).A novel,simple,an...Efficient strategies for transforming Bacillus subtilis vegetative cells into spores(BtS transformation)are still limited,although they show promise for the treatment of inflammatory bowel disease(IBD).A novel,simple,and rapid photo-induced BtS transformation mechanism is now presented that utilizes a novel aggregation-induced emission luminogen(AIEgen)photosensitizer,triphenylamine-benzothiadiazole-pyridine-p-tolylboronic acid bromine salt(TBPBB),that generates reactive oxygen species(ROS)when exposed to light.The ROS selectively target and damage the membranes of Bacillus subtilis and trigger their transformation into spores.These spores demonstrate considerable promise for the effective treatment of IBD in a mouse disease model.Furthermore,thefluorescence signal generated by TBPBB can be used to directly visualize the recovery of damaged intestinal tis-sue.This is a valuable tool for monitoring the healing process and gaining insights into therapeutic efficacy.This study highlights the remarkable practical value of AIEgen-induced BtS transformation for identifying,localizing,and visualizing the therapeutic outcomes of IBD treatments.展开更多
Sn/Yb codoped silica optical fiber preform is prepared by the modified chemical vapor deposition （MCVD） followed by the solution-doping method. Ultraviolet （UV） optical absorption, photoluminescence （PL） spectra...Sn/Yb codoped silica optical fiber preform is prepared by the modified chemical vapor deposition （MCVD） followed by the solution-doping method. Ultraviolet （UV） optical absorption, photoluminescence （PL） spectra under 978-nm laser diode （LD） pumping, and refractive index change after exposure to 266-nm laser pulses are obtained. There is only a little change in the PL spectra while a positive refractive index change up to 2×10^-4 is observed after 30-min exposure to 266-nm laser pulses. The results show that both of the peculiar photosensitivity of Smdoped silica and the gain property of Yb-doped silica fiber are preserved in the Sn/Yb codoped silica optical fiber preform. The experimental data suggest that the photosensitivity of the fiber preform under high energy density laser irradiation should be mainly due to the bond-breaking of oxygen deficient defects, while under relatively low energy density laser irradiation, the refractive index change probably originates from the photoconversion of optically active defects.展开更多
The efficient photo-response mechanism is one of the key factors in the commercialization of dye-sensitized solar cells in a bid to satisfy renewable energy demands. Progress in green technology has put solar energy o...The efficient photo-response mechanism is one of the key factors in the commercialization of dye-sensitized solar cells in a bid to satisfy renewable energy demands. Progress in green technology has put solar energy on the front burner as a provider of clean and affordable energy for a sustainable society. We report the synthesis of a novel Schiff base with optical transparency in the visible and near IR region of the solar spectrum that can find application in the DSSCs photo-response mechanism. The synthesized crystal exhibited features that could handle some of the shortcomings of dye-sensitized solar cells which include wide band solar spectrum absorption and capability for swift charge transfer within the photoelectrodes. The synthesized Schiff base was characterized using x-ray diffractometer, UV/Visible spectrometer, Frontier transmission infrared spectrometer and conductometer. XRD data revealed the grown crystal to have an average crystallite size of 2.08 nm with average microstrain value of about 269.43. The FT-IR recorded transmission wave ѵ (CO) at 1207.7 cm<sup>−1</sup> while dominant wave occurred at ѵ1654.9 and ѵ1592.3 cm<sup>−1</sup> relating to ѵ (CN) stretching and ѵ (NH) bending respectively were observed. The IR spectrum revealed the bonding species and a probable molecular structure of 2,6-bis(benzyloxy)pyridine. The UV/Visible spectra convoluted to maximum peak within the near IR region suggesting that 2,6-bis(benzyloxy)pyridine can absorb both the visible and near IR region while its electrical conductivity was determined to be 4.58 µS/cm. The obtained result of the present study revealed promising characteristics of a photosensitizer that can find application in the photo-response mechanism of DSSCs.展开更多
Leaf color is directly related to altered photosynthesis.Hence,leaf yellowing mutants can be widely used for the researching plant physiology and functional genomes,for cultivating new varieties of popular horticultur...Leaf color is directly related to altered photosynthesis.Hence,leaf yellowing mutants can be widely used for the researching plant physiology and functional genomes,for cultivating new varieties of popular horticultural plants,and for identifying hybrid purity(as markers).Here,we constructed a^(60)Co-γF_(2)population from the leaf-yellowing mutant R24 via radiation mutation with the inbred line WT21 of pepper.Genetic analysis showed that the leaf-yellowing of the mutant was controlled by a single recessive gene.By applying the Bulk Segregation Analysis and Kompetitive Allele Specific PCR markers,the leaf-yellowing gene CaLY1(Capsicum annuum Leaf yellow 1)was mapped on chromosome 9,SNP5791587-SNP6011215,with a size of 214.5 kb.One non-synonymous mutated gene Capana09g000166 was found in the interval.The gene encoded a Psb X,which is the core complex of PSⅡ.Transcriptome analysis further showed that 2301 differentially expressed genes were identified under shading treatment for 24 h in R24.The Gene Ontology enrichment pathways were related to photosynthesis light harvesting,cell wall,activity of quercetin 3-O-glucosyltransferase and flavonoid metabolic process,which likely regulate the response of pepper leaves to different light levels.Functional enrichment analysis indicated that the most abundant pathways were photosynthesis antenna proteins and metabolic.展开更多
Organometal halide perovskites are promising semiconducting materials for photodetectors because of their favorable optoelectrical properties.Although nanoscale perovskite materials such as quantum dots(QDs)show novel...Organometal halide perovskites are promising semiconducting materials for photodetectors because of their favorable optoelectrical properties.Although nanoscale perovskite materials such as quantum dots(QDs)show novel behavior,they have intrinsic stability issues.In this study,an effectively silane barrier-capped quantum dot(QD@APDEMS)is thinly applied onto a bulk perovskite photosensitive layer for use in photodetectors.QD@APDEMS is synthesized with a silane ligand with hydrophobic CH_(3)-terminal groups,resulting in excellent dispersibility and durability to enable effective coating.The introduction of the QD@APDEMS layer results in the formation of a lowdefect perovskite film with enlarged grains.This is attributed to the grain boundary interconnection effect via interaction between the functional groups of QD@APDEMS and uncoordinated Pb^(2+)in grain boundaries.By passivating the grain boundaries,where various trap sites are distributed,hole chargecarrier injection and shunt leakage can be suppressed.Also,from the energy point of view,the deep highest occupied molecular orbital(HOMO)level of QD@APDEMS can work as a hole charge injection barrier.Improved charge dynamics(generation,transfer,and recombination properties)and reduced trap density of QD@APDEMS are demonstrated.When this perovskite film is used in a photodetector,the device performance(especially the detectivity)stands out among existing perovskites evaluated for energy sensing device applications.展开更多
文摘The effect of changing Be doping concentration in GaAs layer on the integrated photosensitivity for nega- tive-electron-affinity GaAs photocathodes is investigated. Two GaAs samples with the monolayer structure and the muhilayer structure are grown by molecular beam epitaxy. The former has a constant Be concentration of 1 × 10^19 cm^-3, while the latter includes four layers with Be doping concentrations of 1 × 10^19, 7 × 10^18, 4 × 10^18, and 1 × 10^18 cm^-3 from the bottom to the surface. Negative-electron-affinity GaAs photocathodes are fabricated by exciting the sample surfaces with alternating input of Cs and O in the high vacuum system. The spectral response results measured by the on-line spectral response measurement system show that the integrated photosensitivity of the photocathode with the muhilayer structure enhanced by at least 50% as compared to that of the monolayer structure. This attributes to the improvement in the crystal quality and the increase in the surface escape probability. Different stress situations are observed on GaAs samples with monolayer structure and muhilayer structure, respectively.
文摘The title polymers PMS 8Pz,M=Mn Ⅱ,Fe Ⅱ,Co Ⅱ,Ni Ⅱ,Cu Ⅱ,Zn Ⅱ,were synthesized by teaction of 2,3,5,6 tetracyano 1,4 dithiin with corresponding metal salts ,respectively.The styucture and properties of these polyers were characterized by elemental analysis,transmission electron microscope,DTA,IR, UV Vis,fluorescence and EPR spectra. It has been found that these conjugated polymers have the property of intrinsic semiconductor. The conductivity σ 298K of these polymers is in the range of 10 -9 ￣10 -3 S · cm -1 under pressure 10.63 MPa and incremental in the metal orderMn < Co<Fe<Zn<Cu<Ni.\ The photosensitivity of the MS 8Pz to the CdS PVA films is incremental in the metal order Zn < Mn < Co < Fe < Cu < Ni.
基金Projected supported by the National Natural Science Foundation of China (Grant No. 61076113)the Natural Science Foundation of Guangdong Province,China (Grant No. 8451064101000257)the Research Grants Council (RGC) of Hong Kong Special Administrative Region (HKSAR),China (Grant No. HKU 7133/07E)
文摘Polymer thin-film transistors （PTFTs） based on poly（3-hexylthiophene） are fabricated by the spin-coating process, and their photo-sensing characteristics are investigated under steady-state visible-light illumination. The photosensitivity of the device is strongly modulated by gate voltage under various illuminations. When the device is in the subthreshold operating mode, a significant increase in its drain current is observed with a maximum photosensitivity of 1.7×10^3 at an illumination intensity of 1200 lx, and even with a relatively high photosensitivity of 611 at a low illumination intensity of 100 lx. However, when the device is in the on-state operating mode, the photosensitivity is very low： only 1.88 at an illumination intensity of 1200 lx for a gate voltage of -20 V and a drain voltage of -20 V. The results indicate that the devices could be used as photo-detectors or sensors in the range of visible light. The modulation mechanism of the photosensitivity in the PTFT is discussed in detail.
基金the National Research Foundation of Korea Grant Funded by the Korean Government, No. KRF-2008-314-E00173
文摘The present study examined a patient with traumatic brain injury who exhibited visual photosensitivity and axonal iniury of the left optic radiation, which was detected by diftusion tensor imaging. The patient was a 41-year-old man. He began to complain of photosensitivity at 4 months after head trauma. Ophthalmic evaluation, including visual-evoked potential and conventional brain magnetic resonance imaging, did not reveal a pathologic basis for photosensitivity. Axonal injury in the left optic radiation was detected via diffusion tensor imaging at 36 months after head trauma. The lesion was almost recovered at 76 months. However, photosensitivity continued. Therefore, the photosensitivity was considered to be a result of axonal injury to the left optic radiation, which could be a symptom of maladaptive plasticity that occurs during recovery of axonal injury of the left optic radiation.
基金Project supported by the National Natural Science Foundation of China (Grant No. 91123017)
文摘We report a novel technique to enhance the ultraviolet （UV） photosensitivity of a ZnO nanosensor with ZnO nanowires bridged on micromachined metallic electrodes. The experimental results reveal that the photoconductivity and the time response of the ZnO nanowire sensor with either Schottky or Ohmic contacts are significantly improved by electrifying the nanowire sensors using an alternating current at the frequency of megahertz. An integrated UV sensor incorporating ZnO nanowires with a constant current mode driving circuit is developed, which demonstrates promising sensitivity and time response to UV illumination with a low power consumption.
文摘The polymerization of methyl acrylate was sensitive to UV light. Under UV light,the rate of polymerization is 8 times as high as the rate in dark.The overall activation energy was decreased by the UV light (313nm).A tentative explanation is given and the mechanism is discussed.
文摘The influences of UV light irradiation (313 nm) and diffused daylight on the polymerization of methyl acrylate initiated by the ceric ammonium nitrate without any reducing agent have been studied both in aqueous nitric acid and in pure water. The rate of polymerization was found to be accelerated and the overall activation energy and the induction time were found to be decreased sharply by the UV light irradiation. Under UV light, the rate of polymerization is 8 times as high as the rate in dark. The rate of polymerization was found to attain a maximum with the increase of nitric acid concentration and the rate of polymerization became less sensitive to UV light in the presence of nitric acid whereas the induction period reduced outstandingly. Based on the experimental results, the mechanism is proposed.
文摘Polymerization of acrylamide initiated by ceric ammonium nitrate alone has been studied in aqueous medium. The effects of UV light irradiation on the initial rates of polymerization, the activation energy and on the polymer molecular weights have been investigated. Compared with that in the dark, the rate of polymerization under UV light was accelerated to eleven times higher, and the overall activation energy was lowered markedly.
文摘Background: Autoantibodies (Aabs) are the hallmark of numerous systemic autoimmune pathologies (SAPs), for instance anti-Ro/SS-A Aabs are usually found in Systemic Lupus Erythematosus (SLE) and Sjogren’s Syndrome. Cutaneous photosensitivity (CP) is found in most forms and subsets of LE and consists of a skin rash as a result of unusual reaction to sunlight. There are many theories which relate specifically the presence of circulating anti-Ro/SS-A Aabs with the CP phenomenon, though there are several studies which are in disagreement. Results: In this study we analyzed the relationship between CP and anti-Ro Aabs by means of two approaches. The first one included an in vitro model where we evaluated by flow cytometry the binding capacity of affinity-purified Aabs to autoantigens relocalized on apoptotic keratinocyte’s surface. We found that there was no relationship between the binding capacity of serum from 10 selected patients or their corresponding purified anti-Ro52 and anti-Ro60 Aabs, and the presence or absence of CP, neither with the SAPs. The in vivo model consisted of Hairless SKH:1 mice which were induced to produce anti-murine Ro52 and/or Ro60 Aabs and were subsequently irradiated with UVB light. We evaluated the skin histology and also the epidermal production of TNF-α. We found no differences between the groups in neither of the parameters evaluated. Conclusions: These results agree with some studies on the role of the Aabs in CP, considering anti-Ro Aabs not as the only responsible for the manifestation;and disagree with many other authors, who believe in the strong association between these two events.
文摘New water soluble and photocrosslinkable prepolymers containing acrylate and quaternary ammonium salt groups were synthesized from epoxy phenolic resin via ring-opening reaction with acrylic acid and with aqueous solution of triethylamine hydrochloride successively. The second reaction needs no phase transfer catalyst to accelerate, since the product formed can act as a phase transfer catalyst. The prepolymer obtained contains both photocrosslinkable acrylate groups and hydrophilic quaternary ammonium salt groups. Optimum conditions for these reactions were studied. The photosensitivity of the prepolymer was also investigated. The effects of different photoinitiators, different crosslinkable diluent monomers and amine accelerator on the photosensitivity of the prepolymer were compared. The photoinitiator of hydrogen abstraction type is still effective without using amine or alcohol as accelerator, because the prepolymer contains a H beside the OH groups formed in the ring-opening reactions.
基金This research was supported by the National Natural Science Foundation of China(Grant Nos.21866017 and 42067056)the Yunnan Fundamental Research Projects(China)(202101BE070001-013 and 202201AU070157)the Foundation for Distinguished Young Talents of Yunnan Province(China)(202101AV070006).
文摘Dissolved organic matter(DOM)from each treatment process of wastewater treatment plants(WWTPs)contains abundant photosensitive substances,which could significantly affect the photodegradation of 17α-ethinylestradiol(EE2).Nevertheless,information about EE2 photodegradation behavior mediated by DOM from diverse WWTPs and the photosensitivity sources of such DOM are inadequate.This study explored the photodegradation behavior of EE2 mediated by four typical WWTPs’DOM solutions and investigated the photosensitivity sources of DOM in the anaerobic-anoxic-oxic(A2/O)process.The parallel factor analysis identified three varying fluorescing components of these DOM,tryptophan-like substances or protein-like substances,microbial humuslike substances,and humic-like components.The photodegradation rate constants of EE2 were positively associated with the humification degree of DOM(P<0.05).The triplet state substances were responsible for the degradation of EE2.DOM extracted from the A2/O process,especially in the secondary treatment process had the fastest EE2 photodegradation rate compared to that of the other three processes.Four types of components(water-soluble organic matter(WSOM),extracellular polymeric substance,humic acid,and fulvic acid)were separated from the A2/O process DOM.WSOM had the highest promotion effect on EE2 photodegradation.Fulvic acid-like components and humic acid-like organic compounds in WSOM were speculated to be important photosensitivity substances that can generate triplet state substances.This research explored the physicochemical properties and photosensitive sources of DOM in WWTPs,and explained the fate of estrogens photodegradation in natural waters.
基金This work was supported by the grants from the National Natural Science Foundation of China （No. 30571969） and the Natural Science Foundation of Beijing （No.7063096）.
文摘Background Electroencephalogram （EEG） activity in normal subjects and epileptic patients is often closely related to the eye＇s status such as eye opened （EO）, eye closure （ECL） and eyes closed （EC）. ECL is the period immediately after closing of the eyes and only lasts for less than 3 seconds if the eyes remain closed. EC is the period as long as the eyes are closed. Epileptiform changes on EEG induced by ECL or EC are called the changes of ECL sensitivity （ECLS） or EC sensitivity （ECS）. ECLS occurs mainly but not exclusively in photosensitive patients and ECS has been seen rarely in photosensitive patients. This study aimed to investigate the relationships among ECLS, ECS, photosensitivity and epilepsy syndromes in children. Methods EEG records from child patients in the EEG Department of Peking University First Hospital during the period of May 2005 to May 2007 were examined for the presence of ECLS or ECS. Open-close eye tests and intermittent photic stimulations were carried out during video-EEG monitoring for examining ECLS, ECS and photosensitivity. Results Based on ECLS and ECS on their EEGs, 30 patients were divided into ECLS group （16 cases） and ECS group （14 cases）. There were more boys than girls in the two groups. The mean age of initial detection of ECLS and ECS was 10 years, and the average onset age of seizures was 9 years. The epilepsy syndromes in the ECLS group included idiopathic photosensitive occipital lobe epilepsy, Panayiotopoulos syndrome, symptomatic occipital lobe epilepsy, juvenile myoclonic epilepsy, juvenile absence epilepsy, eyelid myoclonia with absences, epilepsy with grand mal on awakening and pure photosensitive epilepsy with mainly generalized tonic clonic seizures. Those in the ECS group were juvenile myoclonic epilepsy, idiopathic photosensitive occipital lobe epilepsy, Panayiotopoulos syndrome and Gastaut type-idiopathic children occipital epilepsy. Photosensitivity was detected in 88% of patients with ECLS and 29% of patients with ECS. Conclusions ECLS and ECS are relatively common in females. Comparing with ECS, ECLS is found in more epilepsy syndromes. However, ECS and ECLS could exist in the same epilepsy syndrome. ECLS and ECS can be associated or dissociated with photosensitivity. The rate of ECLS with photosensitivity is higher than that of ECS with photosensitivity, suggesting that mechanisms for ECLS, ECS and photosensitivity may be different but correlated.
基金NSFC,Grant/Award Numbers:52073045,51773195Key Scientific and Technological Project of Jilin Province,Grant/Award Number:20190701010GH+2 种基金Development and Reform Commission of Jilin Province,Grant/Award Number:2020C035-5Changchun Science and Technology Bureau,Grant/Award Number:21ZGY19EPSRC,Grant/Award Number:EP/L02621X/1。
文摘Currently three major problems seriously limit the practical application of can-cer photodynamic therapy(PDT):(i)the hypoxic tumor microenvironment(TME);(ii)low generation efficiency of toxic reactive oxygen species(ROS)in aggre-gates and(iii)shallow tissue penetration depth of excitation light.Very limited approaches are available for addressing all the above three problems with a single design.Herein,a rational“three birds with one stone”molecular and nanoengi-neering strategy is demonstrated:a photodynamic nanoplatform U-Ir@PAA-ABS based on the covalent combination of lanthanide-doped upconversion nanoparti-cles(UCNPs)and an AIE-active dinuclear Ir(III)complex provides a low oxygen concentration-dependent type-I photochemical process upon 980 nm irradiation by Föster resonance energy transfer(FRET).U-Ir@PAA-ABS targets mitochondria and has excellent phototoxicity even in severe hypoxia environments upon 980 nm irradiation,inducing a dual-mode cell death mechanism by apoptosis and ferropto-sis.Taken together,the in vitro and in vivo results demonstrate a successful strategy for improving the efficacy of PDT against hypoxic tumors.
基金financially supported by the National Natural Science Foundation of China (No.21977081)Zhejiang Provincial Natural Science of Foundation of China (No.LQ21H190006)。
文摘Antibacterial agent of activatable photosensitizer not only has the advantages of traditional photosensitizers,such as good curative effect and low resistance,but also has better selectivity for bacteria and lower toxicity to normal tissues.Limited reports of activatable photosensitizer can be used to treat drugresistant bacteria.In order to meet this challenge,we designed and synthesized an activatable photosensitizer(Ce-OHOA),which can not only selectively identify methicillin-resistant Staphylococcus aureus(MRSA)with high expression ofβ-lactamase by fluorescence imaging,but also kill MRSA with less than10 times the concentration and 10 times the irradiation dose of CySG-2 reported.Ce-OHOA not only combines the dual functions of fluorescence diagnosis and photodynamic therapy,but also selectively acts on bacteria with high expression ofβ-lactamase and has little toxicity to normal cells.We expect that the study of this activating photosensitizer will provide a new solution for antibacterial photodynamic therapy(aPDT)of drug-resistant bacteria.
基金National Natural Science Foundation of China,Grant/Award Numbers:22375066,U23A20594GuangDong Basic and Applied Basic Research Foundation,Grant/Award Numbers:2023B1515040003,2022A1515010315。
文摘Aggregate-level photodynamic therapy(PDT)has attracted significant interest and driven substantial advances in multifunction phototheranostic platforms.As exem-plified by two typical instances of aggregation-caused quenching of reactive oxygen species(ROS)and aggregation-induced generation of ROS,the aggregation effect plays a significant role on the ROS generation of photosensitizers(PSs),which is worthy of in-depth exploration and full utilization.However,in contrast to the well-developed researches on the aggregation effect on luminescence,the studies concerning the aggregation effect on ROS generation are currently in a relatively nascent and disjointed stage,lacking guidance from afirmly established research paradigm.To advance this regard,this review aims at providing a consolidated overview of the fundamental principles and research status of aggregation effects on the ROS generation.Here,the research status can be organized into two main facets.One involves the comparison between isolated state and aggregated state,which is mainly conducted by two methods of changing solvent environments and adding adjuvants into a given solvent.The other underscores the distinctions between different aggregate states,consisting of three parts,namely comparison within the same or between different categories based on the classification of single-component and multicomponent aggregates.In this endeavor,we will present our views on cur-rent research methodologies that explore how aggregation affects ROS generation and highlight the design strategies to leverage the aggregation effect to optimize PS regiments.We aspire this review to propel the advancement of phototheranostic plat-forms and accelerate the clinical implementation of precision medicine,and inspire more contributions to aggregate-level photophysics and photochemistry,pushing the aggregate science and materials forward.
基金National Science Foundation of China,Grant/Award Numbers:52003228,52273197Shenzhen Key Laboratory of Functional Aggregate Materials,Grant/Award Number:DSYS20211021111400001Science Technology Innovation Commission of Shenzhen Municipality,Grant/Award Numbers:KQTD20210811090142053,JCYJ20220818103007014,JSGG20220606141800001。
文摘Efficient strategies for transforming Bacillus subtilis vegetative cells into spores(BtS transformation)are still limited,although they show promise for the treatment of inflammatory bowel disease(IBD).A novel,simple,and rapid photo-induced BtS transformation mechanism is now presented that utilizes a novel aggregation-induced emission luminogen(AIEgen)photosensitizer,triphenylamine-benzothiadiazole-pyridine-p-tolylboronic acid bromine salt(TBPBB),that generates reactive oxygen species(ROS)when exposed to light.The ROS selectively target and damage the membranes of Bacillus subtilis and trigger their transformation into spores.These spores demonstrate considerable promise for the effective treatment of IBD in a mouse disease model.Furthermore,thefluorescence signal generated by TBPBB can be used to directly visualize the recovery of damaged intestinal tis-sue.This is a valuable tool for monitoring the healing process and gaining insights into therapeutic efficacy.This study highlights the remarkable practical value of AIEgen-induced BtS transformation for identifying,localizing,and visualizing the therapeutic outcomes of IBD treatments.
基金supported by the National Natural Science Foundation of China (Nos. 10074011 and 60378034)the Ministry of Science and Technology of China (Nos. 02JD14001 and 03DJ14001).
文摘Sn/Yb codoped silica optical fiber preform is prepared by the modified chemical vapor deposition （MCVD） followed by the solution-doping method. Ultraviolet （UV） optical absorption, photoluminescence （PL） spectra under 978-nm laser diode （LD） pumping, and refractive index change after exposure to 266-nm laser pulses are obtained. There is only a little change in the PL spectra while a positive refractive index change up to 2×10^-4 is observed after 30-min exposure to 266-nm laser pulses. The results show that both of the peculiar photosensitivity of Smdoped silica and the gain property of Yb-doped silica fiber are preserved in the Sn/Yb codoped silica optical fiber preform. The experimental data suggest that the photosensitivity of the fiber preform under high energy density laser irradiation should be mainly due to the bond-breaking of oxygen deficient defects, while under relatively low energy density laser irradiation, the refractive index change probably originates from the photoconversion of optically active defects.
文摘The efficient photo-response mechanism is one of the key factors in the commercialization of dye-sensitized solar cells in a bid to satisfy renewable energy demands. Progress in green technology has put solar energy on the front burner as a provider of clean and affordable energy for a sustainable society. We report the synthesis of a novel Schiff base with optical transparency in the visible and near IR region of the solar spectrum that can find application in the DSSCs photo-response mechanism. The synthesized crystal exhibited features that could handle some of the shortcomings of dye-sensitized solar cells which include wide band solar spectrum absorption and capability for swift charge transfer within the photoelectrodes. The synthesized Schiff base was characterized using x-ray diffractometer, UV/Visible spectrometer, Frontier transmission infrared spectrometer and conductometer. XRD data revealed the grown crystal to have an average crystallite size of 2.08 nm with average microstrain value of about 269.43. The FT-IR recorded transmission wave ѵ (CO) at 1207.7 cm<sup>−1</sup> while dominant wave occurred at ѵ1654.9 and ѵ1592.3 cm<sup>−1</sup> relating to ѵ (CN) stretching and ѵ (NH) bending respectively were observed. The IR spectrum revealed the bonding species and a probable molecular structure of 2,6-bis(benzyloxy)pyridine. The UV/Visible spectra convoluted to maximum peak within the near IR region suggesting that 2,6-bis(benzyloxy)pyridine can absorb both the visible and near IR region while its electrical conductivity was determined to be 4.58 µS/cm. The obtained result of the present study revealed promising characteristics of a photosensitizer that can find application in the photo-response mechanism of DSSCs.
基金supported by the earmarked fund for CARS(Grant No.CARS-24-A05)。
文摘Leaf color is directly related to altered photosynthesis.Hence,leaf yellowing mutants can be widely used for the researching plant physiology and functional genomes,for cultivating new varieties of popular horticultural plants,and for identifying hybrid purity(as markers).Here,we constructed a^(60)Co-γF_(2)population from the leaf-yellowing mutant R24 via radiation mutation with the inbred line WT21 of pepper.Genetic analysis showed that the leaf-yellowing of the mutant was controlled by a single recessive gene.By applying the Bulk Segregation Analysis and Kompetitive Allele Specific PCR markers,the leaf-yellowing gene CaLY1(Capsicum annuum Leaf yellow 1)was mapped on chromosome 9,SNP5791587-SNP6011215,with a size of 214.5 kb.One non-synonymous mutated gene Capana09g000166 was found in the interval.The gene encoded a Psb X,which is the core complex of PSⅡ.Transcriptome analysis further showed that 2301 differentially expressed genes were identified under shading treatment for 24 h in R24.The Gene Ontology enrichment pathways were related to photosynthesis light harvesting,cell wall,activity of quercetin 3-O-glucosyltransferase and flavonoid metabolic process,which likely regulate the response of pepper leaves to different light levels.Functional enrichment analysis indicated that the most abundant pathways were photosynthesis antenna proteins and metabolic.
基金Ministry of Trade,Industry and Energy,Grant/Award Numbers:20017439,20021915National Research Foundation of Korea,Grant/Award Number:2019R1A2C1087653。
文摘Organometal halide perovskites are promising semiconducting materials for photodetectors because of their favorable optoelectrical properties.Although nanoscale perovskite materials such as quantum dots(QDs)show novel behavior,they have intrinsic stability issues.In this study,an effectively silane barrier-capped quantum dot(QD@APDEMS)is thinly applied onto a bulk perovskite photosensitive layer for use in photodetectors.QD@APDEMS is synthesized with a silane ligand with hydrophobic CH_(3)-terminal groups,resulting in excellent dispersibility and durability to enable effective coating.The introduction of the QD@APDEMS layer results in the formation of a lowdefect perovskite film with enlarged grains.This is attributed to the grain boundary interconnection effect via interaction between the functional groups of QD@APDEMS and uncoordinated Pb^(2+)in grain boundaries.By passivating the grain boundaries,where various trap sites are distributed,hole chargecarrier injection and shunt leakage can be suppressed.Also,from the energy point of view,the deep highest occupied molecular orbital(HOMO)level of QD@APDEMS can work as a hole charge injection barrier.Improved charge dynamics(generation,transfer,and recombination properties)and reduced trap density of QD@APDEMS are demonstrated.When this perovskite film is used in a photodetector,the device performance(especially the detectivity)stands out among existing perovskites evaluated for energy sensing device applications.
