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
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
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
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
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
A nanomicelle(denoted as TPGS/Ppa)was fabricated via the coassembly of the amphiphilic D-α-tocopheryl polyethylene glycol 1000 succinate(TPGS)and the hydrophobic photosensitizer pyropheophorbide a(Ppa)for photodynami...A nanomicelle(denoted as TPGS/Ppa)was fabricated via the coassembly of the amphiphilic D-α-tocopheryl polyethylene glycol 1000 succinate(TPGS)and the hydrophobic photosensitizer pyropheophorbide a(Ppa)for photodynamic therapy(PDT).The obtained nanomicelle possessed a spherical structure with a diameter of(18.0±2.2)nm and a zeta potential of approximately -18 mV.Besides,the nanomicelle exhibited excellent photostability,biocompatibility,and phototoxicity,and could effectively reach the tumor region via the enhanced permeability and retention effect.Additionally,it could be found that the TPGS/Ppa nanomicelle exhibited higher phototoxicity against 4T1 murine mammary cancer cells than free Ppa.In the 4T1 tumor-bearing mouse model,the nanomicelle showed an excellent antitumor therapeutic effect.This study develops a new type of photodynamic nanomicelle TPGS/Ppa,which can increase the accumulation of drugs and prolong their tumor retention time,providing a feasible strategy for realizing the delivery of small-molecule hydrophobic drugs and tumor PDT.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
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
This study investigates the intersystem crossing(ISC)mechanism in donor-acceptor(D-A)type distyryl-BODIPY photosensitizers,including previously reported M1(benzene donor),M2,M3(phenothiazine donors),and newly predicte...This study investigates the intersystem crossing(ISC)mechanism in donor-acceptor(D-A)type distyryl-BODIPY photosensitizers,including previously reported M1(benzene donor),M2,M3(phenothiazine donors),and newly predicted M4(triphenylamine donor),M5-M7(nitrogen-containing aliphatic rings with thiophene donors).Using computational chemistry,we analyzed their geometric configurations,spectral properties,spin-orbit coupling,and electron-hole orbitals.We found that S_(2) is a charge transfer singlet state(^(1)CT),T2is a locally excited triplet state(^(3)LE),and the S_(2)→T_(2)transition is the main ISC pathway in M2-M7,following the ^(1)CT→^(3)LE mechanism.M5-M7 show near-vertical dihedral angles between donor and acceptor in the S_(2) state relative to M2-M4,facilitating charge transfer.The strain energies in the nitrogen-containing rings of M5-M7 affect oxidation potentials and ISC.M5,with the highest strain energy,shows the lowest oxidation potential,smaller△_(ES2-T2),highest SOC,and fastest kisc,making it the most efficient predicted singlet oxygen producer.This research clarifies the structure-performance relationships of near-infrared D-A type distyryl-BODIPY photosensitizers and provides a theoretical foundation for developing heavy-atom-free photosensitizers with tuned fluorescence quantum yield and singlet oxygen quantum yield.展开更多
Pt(Ⅱ)-salophen complexes(S-1~S-4) and 9,10-diphenylanthracene(DPA) tethering pillar[5]arene derivatives(A-1 and A-2) were synthesized to act as sensitizers and annihilators for triplet-triplet annihilation upconversi...Pt(Ⅱ)-salophen complexes(S-1~S-4) and 9,10-diphenylanthracene(DPA) tethering pillar[5]arene derivatives(A-1 and A-2) were synthesized to act as sensitizers and annihilators for triplet-triplet annihilation upconversion(TTA-UC), respectively. It turned out that the pyridine cation served as a mask for the excited state of the sensitizer, the triplet states of S-2 and S-3 were significantly quenched by photo-induced electron transfer(PET) with phosphorescence quantum yield quenched from 24.4% for S-4 to 9.3% for S-3,and therefore, both S-2 and S-3 led to negligible UC emissions when traditional annihilator DPA was used as the annihilator. Delightfully, when supramolecular annihilator A-1 and A-2 were employed to include the pyridine cation, PET was significantly inhibited and the triplet states of the sensitizers were activated,TTA-UC emission was therefore boosted. The UC quantum yield of A-2/S-3 system was up to 130 times higher than that of DPA/S-3 system, and the UC emission was switchable by the addition of competitive vips.展开更多
The rapid emergence of drug-resistant bacterial strains undermines the efficacy of conventional antibiotics,necessitating the development of alternative therapies.Antimicrobial photodynamic therapy(PDT)is a promising ...The rapid emergence of drug-resistant bacterial strains undermines the efficacy of conventional antibiotics,necessitating the development of alternative therapies.Antimicrobial photodynamic therapy(PDT)is a promising approach,but its effectiveness is often limited by the suboptimal photocatalytic activity of photosensitizers.In this study,we introduce a novel photoresponsive carbon-based antibacterial agent,Ce6/g-C_(3)N_(4),which combines the photocatalytic properties of graphite-phase carbon nitride(g-C_(3)N_(4))with the photodynamic attributes of chlorin e6(Ce6).This agent,with an average particle size of 250.7 nm,demonstrates significantly enhanced photocatalytic activity.Additionally,the strong affinity of Ce6/g-C_(3)N_(4)for bacteria and efficient delivery of Ce6 result in an inhibition rate exceeding 99%against Gram-positive bacteria and excellent biofilm eradication under light irradiation.In vivo experiments reveal that Ce6/gC_(3)N_(4)effectively inhibits bacterial growth on wounds,and promotes wound healing post-light treatment,while maintaining good biocompatibility.Overall,the Ce6/g-C_(3)N_(4)antibacterial agent synergizes photodynamic and photocatalytic mechanisms,offering a new avenue for the photo-mediated,multi-strategic treatment of bacterial infections and wound healing.展开更多
Nitrate renoxification significantly influences atmospheric nitrogen cycling and global OH budgets.Although numerous nitrite acid(HONO)formation pathways from nitrate photolysis have been widely reported,the influence...Nitrate renoxification significantly influences atmospheric nitrogen cycling and global OH budgets.Although numerous nitrite acid(HONO)formation pathways from nitrate photolysis have been widely reported,the influence of various environmental factors and aerosol properties on reactive nitrogen production remains largely unclear.In this work,we employed NaNO_(3)/humic acid(HA)as a model nitrate photosensitization system to investigate the crucial roles of aerosol acidity,organic fraction,and dissolved oxygen in the production of HONO,NO_(2),and NO_(2)^(-).The presence of HA at 10 mg/L resulted in a remarkable increase in HONO production rates by approximately 2–3 times and NO_(2)^(-) concentration by 3–6 times across a pH range of 5.2 to 2.0.Meanwhile,the molar fraction of gaseous HONO in total N(Ⅲ)production increased from4%to 69%as bulk-phase pH decreased from 5.2 to 2.0.The higher organic fraction(i.e.,20 and 50 mg/L HA concentration)instead inhibited HONO and NO_(2) release.The presence of dissolved oxygen was found to be adverse for reactive nitrogen production.This suggests that the HA photosensitizer promoted the secondary conversion of NO_(2) to HONO mainly via reduced ketyl radical intermediates,while superoxide radical formation might exert a negative effect.Our findings provide comprehensive insights into reactive nitrogen production from photosensitized nitrate photolysis mediated by various external and internal factors,potentially accounting for discrepancies between field observations and model simulations.展开更多
Photodynamic therapy (PDT) is undoubtedly a cutting-edge strategy for precise tumor therapy because of its unprecedented superiorities, such as negligible long-lasting adverse effects, high spatial and temporal select...Photodynamic therapy (PDT) is undoubtedly a cutting-edge strategy for precise tumor therapy because of its unprecedented superiorities, such as negligible long-lasting adverse effects, high spatial and temporal selectivity, and inappreciable drug resistance. While the operation wavelengths of the commonly used photosensitizers (PSs) are located in visible or first near-infrared (NIR-I, 650–900 nm) region. The lights in these regions possess relatively low penetration depth, which makes PDT unsuitable for deep-tissue treatment. Near-infrared-II (NIR-II, 1000–1700 nm) light with high tissue penetration ability can be employed as excitation source for PDT, which provides a promising alternative for precision therapy of deep-seated tumors. However, designing NIR-II activated PSs is in its infancy, and still faces many challenges, such as severe nonradiative relaxation and difficulties in adjusting energy levels. This paper reviews the therapeutic mechanisms of PDT and recent strategies for designing NIR-II activated inorganic PSs. The inorganic NIR-II PSs are classified based on their functions (such as type II PSs, type I PSs, and PSs with specific properties), and their applications for effective and precision deep-tissue treatment are summarized comprehensively. Furthermore, the major issues of applying these PSs in clinical practices are also discussed.展开更多
Innovative anti-cancer therapies that activate the immune system show promise in combating cancers resistant to conventional treatments.Photodynamic therapy(PDT)is one such treatment,which not only directly eliminates...Innovative anti-cancer therapies that activate the immune system show promise in combating cancers resistant to conventional treatments.Photodynamic therapy(PDT)is one such treatment,which not only directly eliminates tumor cells but also functions as an in situ tumor vaccine by enhancing tumor immunogenicity and triggering anti-tumor immune responses through immunogenic cell death(ICD).However,the effectiveness of PDT in enhancing immune responses is influenced by factors,such as photosensitizers and the tumor microenvironment,particularly hypoxia.Current clinically used PDT heavily relies on oxygen(O_(2))availability and can be limited by tumor hypoxia.Additionally,the tumor immunosuppressive microenvironment induced by hypoxia affects the anti-tumor immunity of tumor-infiltrating effector T cells.Meanwhile,the immunosuppressive myeloid-lineage cells are recruited to the hypoxic tumor tissue and exhibit higher immunosuppressive capabilities under hypoxia conditions.Consequently,numerous strategies have been developed to modulate tumor hypoxia or to create hypoxia-compatible PDT,aiming to reduce the effects of tumor hypoxia on PDT-driven immunotherapy.This review investigates these strategies,including approaches to alleviate,exploit,and disregard tumor hypoxia within the context of PDT/immunotherapy.It also emphasizes the role of advanced nanomedicine and its benefits in these strategies,while outlining current challenges and future prospects in the field.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 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.
文摘A nanomicelle(denoted as TPGS/Ppa)was fabricated via the coassembly of the amphiphilic D-α-tocopheryl polyethylene glycol 1000 succinate(TPGS)and the hydrophobic photosensitizer pyropheophorbide a(Ppa)for photodynamic therapy(PDT).The obtained nanomicelle possessed a spherical structure with a diameter of(18.0±2.2)nm and a zeta potential of approximately -18 mV.Besides,the nanomicelle exhibited excellent photostability,biocompatibility,and phototoxicity,and could effectively reach the tumor region via the enhanced permeability and retention effect.Additionally,it could be found that the TPGS/Ppa nanomicelle exhibited higher phototoxicity against 4T1 murine mammary cancer cells than free Ppa.In the 4T1 tumor-bearing mouse model,the nanomicelle showed an excellent antitumor therapeutic effect.This study develops a new type of photodynamic nanomicelle TPGS/Ppa,which can increase the accumulation of drugs and prolong their tumor retention time,providing a feasible strategy for realizing the delivery of small-molecule hydrophobic drugs and tumor PDT.
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.
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financially supported by the Fundamental Research Funds for the Central Universities(No.DUT20RC(3)076)Natural Science Foundation of Liaoning Province(No.2020-MS293)。
文摘This study investigates the intersystem crossing(ISC)mechanism in donor-acceptor(D-A)type distyryl-BODIPY photosensitizers,including previously reported M1(benzene donor),M2,M3(phenothiazine donors),and newly predicted M4(triphenylamine donor),M5-M7(nitrogen-containing aliphatic rings with thiophene donors).Using computational chemistry,we analyzed their geometric configurations,spectral properties,spin-orbit coupling,and electron-hole orbitals.We found that S_(2) is a charge transfer singlet state(^(1)CT),T2is a locally excited triplet state(^(3)LE),and the S_(2)→T_(2)transition is the main ISC pathway in M2-M7,following the ^(1)CT→^(3)LE mechanism.M5-M7 show near-vertical dihedral angles between donor and acceptor in the S_(2) state relative to M2-M4,facilitating charge transfer.The strain energies in the nitrogen-containing rings of M5-M7 affect oxidation potentials and ISC.M5,with the highest strain energy,shows the lowest oxidation potential,smaller△_(ES2-T2),highest SOC,and fastest kisc,making it the most efficient predicted singlet oxygen producer.This research clarifies the structure-performance relationships of near-infrared D-A type distyryl-BODIPY photosensitizers and provides a theoretical foundation for developing heavy-atom-free photosensitizers with tuned fluorescence quantum yield and singlet oxygen quantum yield.
基金supported by the National Natural Science Foundation of China (Nos. 22171194, 21971169, 92056116 and 21871194)the Fundamental Research Funds for the Central Universities (No. 20826041D4117)the Science & Technology Department of Sichuan Province (Nos. 2022YFH0095 and 2021ZYD0052)。
文摘Pt(Ⅱ)-salophen complexes(S-1~S-4) and 9,10-diphenylanthracene(DPA) tethering pillar[5]arene derivatives(A-1 and A-2) were synthesized to act as sensitizers and annihilators for triplet-triplet annihilation upconversion(TTA-UC), respectively. It turned out that the pyridine cation served as a mask for the excited state of the sensitizer, the triplet states of S-2 and S-3 were significantly quenched by photo-induced electron transfer(PET) with phosphorescence quantum yield quenched from 24.4% for S-4 to 9.3% for S-3,and therefore, both S-2 and S-3 led to negligible UC emissions when traditional annihilator DPA was used as the annihilator. Delightfully, when supramolecular annihilator A-1 and A-2 were employed to include the pyridine cation, PET was significantly inhibited and the triplet states of the sensitizers were activated,TTA-UC emission was therefore boosted. The UC quantum yield of A-2/S-3 system was up to 130 times higher than that of DPA/S-3 system, and the UC emission was switchable by the addition of competitive vips.
基金supported by the Natural Science Foundation of the Jiangsu Higher Education Institutes of China(No.22KJB530006)Hainan Provincial Natural Science Foundation of China(No.824QN267)。
文摘The rapid emergence of drug-resistant bacterial strains undermines the efficacy of conventional antibiotics,necessitating the development of alternative therapies.Antimicrobial photodynamic therapy(PDT)is a promising approach,but its effectiveness is often limited by the suboptimal photocatalytic activity of photosensitizers.In this study,we introduce a novel photoresponsive carbon-based antibacterial agent,Ce6/g-C_(3)N_(4),which combines the photocatalytic properties of graphite-phase carbon nitride(g-C_(3)N_(4))with the photodynamic attributes of chlorin e6(Ce6).This agent,with an average particle size of 250.7 nm,demonstrates significantly enhanced photocatalytic activity.Additionally,the strong affinity of Ce6/g-C_(3)N_(4)for bacteria and efficient delivery of Ce6 result in an inhibition rate exceeding 99%against Gram-positive bacteria and excellent biofilm eradication under light irradiation.In vivo experiments reveal that Ce6/gC_(3)N_(4)effectively inhibits bacterial growth on wounds,and promotes wound healing post-light treatment,while maintaining good biocompatibility.Overall,the Ce6/g-C_(3)N_(4)antibacterial agent synergizes photodynamic and photocatalytic mechanisms,offering a new avenue for the photo-mediated,multi-strategic treatment of bacterial infections and wound healing.
基金supported by the National Key R&D Program of China(No.2022YFC3701102)the National Natural Science Foundation of China(Nos.22376029,22176038,91744205 and 21777025)the Natural Science Foundation of Shanghai City(No.22ZR1404700).
文摘Nitrate renoxification significantly influences atmospheric nitrogen cycling and global OH budgets.Although numerous nitrite acid(HONO)formation pathways from nitrate photolysis have been widely reported,the influence of various environmental factors and aerosol properties on reactive nitrogen production remains largely unclear.In this work,we employed NaNO_(3)/humic acid(HA)as a model nitrate photosensitization system to investigate the crucial roles of aerosol acidity,organic fraction,and dissolved oxygen in the production of HONO,NO_(2),and NO_(2)^(-).The presence of HA at 10 mg/L resulted in a remarkable increase in HONO production rates by approximately 2–3 times and NO_(2)^(-) concentration by 3–6 times across a pH range of 5.2 to 2.0.Meanwhile,the molar fraction of gaseous HONO in total N(Ⅲ)production increased from4%to 69%as bulk-phase pH decreased from 5.2 to 2.0.The higher organic fraction(i.e.,20 and 50 mg/L HA concentration)instead inhibited HONO and NO_(2) release.The presence of dissolved oxygen was found to be adverse for reactive nitrogen production.This suggests that the HA photosensitizer promoted the secondary conversion of NO_(2) to HONO mainly via reduced ketyl radical intermediates,while superoxide radical formation might exert a negative effect.Our findings provide comprehensive insights into reactive nitrogen production from photosensitized nitrate photolysis mediated by various external and internal factors,potentially accounting for discrepancies between field observations and model simulations.
基金supported by the National Natural Science Foundation of China(Nos.22175098,52373142)the Jiangsu Planned Projects for Postdoctoral Research Funds(No.2021K114B)the Huali Talents Program of Nanjing University of Posts and Telecommunications,the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX23_0984)。
文摘Photodynamic therapy (PDT) is undoubtedly a cutting-edge strategy for precise tumor therapy because of its unprecedented superiorities, such as negligible long-lasting adverse effects, high spatial and temporal selectivity, and inappreciable drug resistance. While the operation wavelengths of the commonly used photosensitizers (PSs) are located in visible or first near-infrared (NIR-I, 650–900 nm) region. The lights in these regions possess relatively low penetration depth, which makes PDT unsuitable for deep-tissue treatment. Near-infrared-II (NIR-II, 1000–1700 nm) light with high tissue penetration ability can be employed as excitation source for PDT, which provides a promising alternative for precision therapy of deep-seated tumors. However, designing NIR-II activated PSs is in its infancy, and still faces many challenges, such as severe nonradiative relaxation and difficulties in adjusting energy levels. This paper reviews the therapeutic mechanisms of PDT and recent strategies for designing NIR-II activated inorganic PSs. The inorganic NIR-II PSs are classified based on their functions (such as type II PSs, type I PSs, and PSs with specific properties), and their applications for effective and precision deep-tissue treatment are summarized comprehensively. Furthermore, the major issues of applying these PSs in clinical practices are also discussed.
基金supported by the Qin Chuangyuan Traditional Chinese Medicine(TCM)and Innovation Research and Development Project of Shaanxi Provincial Administration of TCM(No.2022-QCYZH-017)Natural Science Foundation of Zhejiang Province(No.LY24E030010)+5 种基金Natural Science Foundation of Shaanxi Province(Nos.2022JM183,2024JC-YBMS-272)the Shaanxi Fundamental Science Research Project for Chemistry&Biology(No.22JHQ072)Shaanxi Provincial Key R&D Program(No.2022SF-342HZ)the Fundamental Research Funds for the Central Universities(Nos.xzy012022037,xzy012023002)the Postdoctoral Science Foundation of Shaanxi Province(No.2023BSHYDZZ05)Foundation by Shaanxi Provincial Administration of TCM(No.2021-ZZ-JC032)。
文摘Innovative anti-cancer therapies that activate the immune system show promise in combating cancers resistant to conventional treatments.Photodynamic therapy(PDT)is one such treatment,which not only directly eliminates tumor cells but also functions as an in situ tumor vaccine by enhancing tumor immunogenicity and triggering anti-tumor immune responses through immunogenic cell death(ICD).However,the effectiveness of PDT in enhancing immune responses is influenced by factors,such as photosensitizers and the tumor microenvironment,particularly hypoxia.Current clinically used PDT heavily relies on oxygen(O_(2))availability and can be limited by tumor hypoxia.Additionally,the tumor immunosuppressive microenvironment induced by hypoxia affects the anti-tumor immunity of tumor-infiltrating effector T cells.Meanwhile,the immunosuppressive myeloid-lineage cells are recruited to the hypoxic tumor tissue and exhibit higher immunosuppressive capabilities under hypoxia conditions.Consequently,numerous strategies have been developed to modulate tumor hypoxia or to create hypoxia-compatible PDT,aiming to reduce the effects of tumor hypoxia on PDT-driven immunotherapy.This review investigates these strategies,including approaches to alleviate,exploit,and disregard tumor hypoxia within the context of PDT/immunotherapy.It also emphasizes the role of advanced nanomedicine and its benefits in these strategies,while outlining current challenges and future prospects in the field.
