RESUMEN
Hole-transporting layers (HTLs) play a crucial role in the performance of inverted, p-i-n perovskite solar cells (PSCs). Chlorophylls (Chls) are naturally abundant organic photoconductors on earth, with good charge carrier mobility and appropriate Fermi energy levels that make them promising candidates for use in photovoltaic devices. However, Chls films prepared using the solution method exhibit lower carrier mobility compared to other organic polymer films, which limits their application in PSCs. To address this issue, Chls molecules are chemically linked to reduce the charge transfer barrier, thus the transfer of charges between molecules is transformed to intramolecular charge transfer. This study synthesizes and characterizes two polymerized Chl films, PolyCuChl and PolyNiChl, as HTLs of CH3 NH3 PbI3 -based PSCs. PSCs based on the electrochemical polymerization of PolyChl HTLs demonstrate an enhanced power conversion efficiency (PCE) of up to 19.0%, which is the highest efficiency among devices based on Chl materials. Furthermore, these devices demonstrated exceptional long-term stability. These results highlight the potential of polymerized Chl films as a viable alternative to conventional HTLs in PSCs. The approach utilizes abundant, environmentally friendly, and versatile Chl derivatives, and can be extended to develop next-generation HTL materials for improved PSC performance.
RESUMEN
The high activity of water molecules results in a series of awful parasitic reaction, which seriously impede the development of aqueous zinc batteries. Herein, a new gel electrolyte with multiple molecular anchors is designed by employing natural biomaterials from chitosan and chlorophyll derivative. The gel electrolyte firmly anchors water molecules by ternary hydrogen bonding to reduce the activity of water molecules and inhibit hydrogen evolution reaction. Meanwhile, the multipolar charged functional groups realize the gradient induction and redistribution of Zn2+ , which drives oriented Zn (002) plane deposition of Zn2+ and then achieves uniform Zn deposition and dendrite-free anode. As a result, it endows the Zn||Zn cell with over 1700 h stripping/plating processes and a high efficiency of 99.4% for the Zn||Cu cell. In addition, the Zn||V2 O5 full cells also exhibit capacity retention of 81.7% after 600 cycles at 0.5 A g-1 and excellent long-term stability over 1600 cycles at 2 A g-1 , and the flexible pouch cells can provide stable power for light-emitting diodes even after repeated bending. The gel electrolyte strategy provides a reference for reversible zinc anode and flexible wearable devices.
RESUMEN
The organic electrolyte can resolve the hurdle of hydrogen evolution in aqueous electrolytes but suffers from sluggish electrochemical reaction kinetics due to a compromised mass transfer process. Herein, we introduce a chlorophyll, zinc methyl 3-devinyl-3-hydroxymethyl-pyropheophorbide-a (Chl), as a multifunctional electrolyte additive for aprotic zinc batteries to address the related dynamic problems in organic electrolyte systems. The Chl exhibits multisite zincophilicity, which significantly reduces the nucleation potential, increases the nucleation sites, and induces uniform nucleation of Zn metal with a nucleation overpotential close to zero. Furthermore, the lower LUMO of Chl contributes to a Zn-N-bond-containing SEI layer and inhibits the decomposition of the electrolyte. Therefore, the electrolyte enables repeated zinc stripping/plating up to 2000 h (2 Ah cm-2 cumulative capacity) with an overpotential of only 32 mV and a high Coulomb efficiency of 99.4%. This work is expected to enlighten the practical application of organic electrolyte systems.
RESUMEN
Hydrogen energy is an abundant, clean, sustainable and environmentally friendly renewable energy source. Therefore, the production of hydrogen by photocatalytically splitting water on semiconductors has been considered in recent years as a promising and sustainable strategy for converting solar energy into chemical energy to replace conventional energy sources and to solve the growing problem of environmental pollution and the global energy crisis. However, highly efficient solar-driven photocatalytic hydrogen production remains a huge challenge due to the poor visible light response of available photocatalytic materials and the low efficiency of separation and transfer of photogenerated electron-hole pairs. In the present work, organic heterojunction structures based on bacteriochlorophyll (BChl) and chlorophyll (Chl) molecules were introduced and used for solar-driven photocatalytic hydrogen production from water under visible light. Also, noble metal-free photocatalyst was successfully constructed on Ti3 C2 Tx nanosheets by simple successive deposition of Chl and BChl, which was used for the photocatalytic splitting water to hydrogen evolution reaction (HER). The results show that the optimal BChl@Chl@Ti3 C2 Tx composite has a high HER performance with 114â µmol/h/gcat , which is much higher than the BChl@Ti3 C2 Tx and Chl@Ti3 C2 Tx composites.
Asunto(s)
Bacterioclorofilas , Procesos Fotoquímicos , Catálisis , Clorofila , Hidrógeno/química , Agua/químicaRESUMEN
The power conversion efficiency (PCE) of Cs2AgBiBr6-based perovskite solar cells (PSCs) is still low owing to the inherent defects of Cs2AgBiBr6 films. Herein, we demonstrate a carboxy-chlorophyll derivative (C-Chl)-sensitized mesoporous TiO2 (m-TiO2) film as an electron transport layer (ETL) to enhance and extend the absorption spectrum of Cs2AgBiBr6-based PSCs. The C-Chl-based device achieves a significantly improved PCE, exceeding 3% for the first time, with an increase of 27% in short-circuit current density. Optoelectronic investigations confirm that the introduction of C-Chl reduces the defects, accelerates the electron extraction, and suppresses charge recombination at the interface of ETL/perovskite. Moreover, the unencapsulated PSCs display restrained hysteresis and great stability under ambient conditions.
RESUMEN
The Z-scheme process is a photoinduced electron-transfer pathway in natural oxygenic photosynthesis involving electron transport from photosystemâ II (PSII) to photosystemâ I (PSI). Inspired by the interesting Z-scheme process, herein a photocatalytic hydrogen evolution reaction (HER) employing chlorophyll (Chl) derivatives, Chl-1 and Chl-2, on the surface of Ti3 C2 Tx MXene with two-dimensional accordion-like morphology, forming Chl-1@Chl-2@Ti3 C2 Tx composite, is demonstrated. Due to the frontier molecular orbital energy alignments of Chl-1 and Chl-2, sublayer Chl-1 is a simulation of PSI, whereas upper layer Chl-2 is equivalent to PSII, and the resultant electron transport can take place from Chl-2 to Chl-1. Under the illumination of visible light (>420â nm), the HER performance of Chl-1@Chl-2@Ti3 C2 Tx photocatalyst was found to be as high as 143â µmol h-1 gcat -1 , which was substantially higher than that of photocatalysts of either Chl-1@Ti3 C2 Tx (20â µmol h-1 g-1 ) or Chl-2@Ti3 C2 Tx (15â µmol h-1 g-1 ).
Asunto(s)
Clorofila , Titanio , Hidrógeno , Complejo de Proteína del Fotosistema I/metabolismo , Complejo de Proteína del Fotosistema II/metabolismoRESUMEN
PURPOSE: To evaluate the efficacy of real-time PCR for 16S ribosomal DNA (16S r-DNA) and sequencing for diagnosing microbial keratitis. METHODS: We studied 272 eyes of 272 patients with keratitis. Eyes with keratitis were classified as "definite" (N = 118), "likely" (N = 71), or "non-bacterial" (N = 83) to have bacterial keratitis. The diagnostic efficacy of real-time PCR and conventional testing was determined by receiver operating characteristic analysis. The copy numbers of bacterial DNA and clinical characteristics were retrospectively analyzed for association with concordant culture results in the "definite" cases. RESULTS: The level of bacterial DNA was significantly associated with the diagnostic probability of the three diagnostic categories. The level of bacterial DNA had comparable diagnostic efficacy with the area under the curve (AUC) at 0.67, by culture at 0.65, and by smear testing at 0.73. The efficacy was significantly improved by combining the DNA level with the conventional culture testing with an AUC of 0.81. Analysis of the "definite" cases showed culture positivity in 51.8% (58 eyes), and of these, 41 eyes (70.7%) were higher than the cutoff PCR values and 40 eyes were identified by 16S r-DNA sequencing. In the culture-negative eyes, the level of bacterial DNA was significantly lower (P = 0.0008). Eyes with higher bacterial DNA levels had significantly concordant outcomes with sequencing and culture results (P = 0.006). Previous antibiotic treatments decreased the bacterial DNA amount by 0.09-fold, and it was a significant factor for discordance (P = 0.006). CONCLUSION: Quantification of the bacterial DNA level and conventional testing improves the diagnostic efficacy of infectious bacterial keratitis.
Asunto(s)
ADN Bacteriano/genética , Infecciones Bacterianas del Ojo/diagnóstico , Queratitis/diagnóstico , ARN Ribosómico 16S/genética , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Infecciones Bacterianas del Ojo/genética , Infecciones Bacterianas del Ojo/microbiología , Femenino , Humanos , Queratitis/genética , Queratitis/microbiología , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Estudios RetrospectivosRESUMEN
We fabricated a chlorophyll (Chl)-based biosolar cell with H2Chl-sensitized TiO2 as an acceptor and (ZnChl)n as a donor. This solar cell gives a relatively high quantum yield from the absorption spectral contribution from both the donor and acceptor species. We employed subpicosecond time-resolved absorption spectroscopy (TAS) to study the excited state dynamics at the Chl interface. A charge transfer (CT) state between TiO2-H2Chl and (ZnChl)n was observed at 640 nm after excitation at the Qy peaks, 680 nm and 720 nm. This CT state is entirely different from the CT states observed for either TiO2-H2Chl (TiO2-H2Chl/spiro-OMeTAD) or TiO2-(ZnChl)n systems. Due to the slower charge transfer process from H2Chl+ to TiO2 as compared to that from (ZnChl)n+ to H2Chl, the CT lifetimes of H2Chl--(ZnChl)n+ (τ1 = 0.1 ps, τ2 = 1.4 ps) excited at 720 nm are slightly shorter than that excited at 680 nm (τ1 = 0.2 ps, τ2 = 5.6 ps). The TAS results suggest that the interface of TiO2-H2Chl and (ZnChl)n not only transfers holes as spiro-OMeTAD does, but also provides a built-in field for charge dissociation between the two Chl species.
RESUMEN
Native coelenterazine (nCTZ) is a common substrate to most marine luciferases and photoproteins. In this study, nine novel dye- and azide-conjugated CTZ analogues were synthesized by conjugating a series of fluorescent dyes or an azide group to the C-2 or C-6 position of the nCTZ backbone to obtain bulkiness-driven substrate specificity and potential chemiluminescence/bioluminescence resonance energy transfer (C/BRET). The investigation on the optical properties revealed that azide-conjugated CTZs emit greatly biased bioluminescence to ALucs and ca. 130 nm blue-shifted bioluminescence with RLuc8.6 in living animal cells or lysates. The corresponding kinetic study explains that azide-conjugated CTZ exerts higher catalytic efficiency than nCTZ. Nile red-conjugated CTZ completely showed red-shifted CRET spectra and characteristic BRET spectra with artificial luciferase 16 (ALuc16). No or less spectral overlap occurs among [Furimazine-NanoLuc], [6-N3-CTZ-ALuc26], [6-pi-OH-CTZ-RLuc8.6], and [6-N3-CTZ-RLuc8.6] pairs, because of the substrate-driven luciferase specificity and color shifts, providing a crosstalk-free multiplex bioassay platform. The unique bioluminescence system appends a new toolbox to bioassays and multiplex molecular imaging platforms. This study is the first example that systematically synthesized fluorescent dye-conjugated CTZs and applied them for a bioluminescence assay system.
Asunto(s)
Azidas/química , Colorantes Fluorescentes/química , Imidazoles/química , Pirazinas/química , Animales , Azidas/síntesis química , Células COS , Chlorocebus aethiops , Colorantes Fluorescentes/síntesis química , Imidazoles/síntesis química , Luciferasas/química , Sustancias Luminiscentes/química , Mediciones Luminiscentes , Imagen Molecular , Pirazinas/síntesis químicaRESUMEN
Solid-state chlorophyll solar cells (CSCs) employing a carboxylated chlorophyll derivative, methyl trans-32 -carboxypyropheophorbideâ a, as a light-harvesting dye sensitizer chlorophyll (DSC) deposited on mesoporous TiO2 , on which four zinc hydroxylated chlorophyll derivatives were spin-coated for hole transporter chlorophylls (HTCs), are described. Key parameters, including the effective carrier mobility of the HTC films, as determined by the space charge-limited current method, and the frontier molecular orbitals of these DSCs and HTCs, as estimated from cyclic voltammetry and electronic absorption spectra, suggest that both charge separation and carrier transport are favorable. The power conversion efficiencies (PCEs) of the present CSCs with fluorine-doped tin oxide (FTO)/TiO2 /DSC/HTCs/Ag were determined to follow the order of HTC-1>HTC-2>HTC-3>HTC-4, which coincided perfectly with the order of their hole mobilities. The maximum PCE achieved was 0.86 % with HTC-1. The photovoltaic devices studied herein with two types of chlorophyll derivatives as dye sensitizers and hole transporters provide a unique solution for the utilization of solar energy with a view to truly realizing "green energy".
RESUMEN
PURPOSE: To determine the relationships between the levels of intraocular inflammatory cytokines and the clinical characteristics of myopic choroidal neovascularization (mCNV) in eyes with myopic maculopathy. METHODS: One hundred eyes of 100 cases, including 51 mCNV eyes, 14 highly myopic eyes without choroidal neovascularization, and 35 normal subjects, were studied. The intraocular levels of choroidal neovascularization-related cytokines, like vascular endothelial growth factor, MCP-1, IL-8, IL-10, and IL-23, were determined. RESULTS: The levels of vascular endothelial growth factor and IL-8 were significantly higher in eyes with mCNV than in high myopia eyes without mCNV with significant odds ratio of 2.00 and 2.25 per quartile, respectively (P < 0.05). When myopic lesions of patients with mCNV were classified into 3 categories based on the severity, IL-8 and MCP-1 were significantly elevated depending on the presence of maculopathy (P < 0.05). Vascular endothelial growth factor was significantly elevated in eyes of Category 2. An advancement of the maculopathy category was significantly associated with the need for multiple treatment of intravitreal bevacizumab (P < 0.05). In 12 eyes that required multiple intravitreal bevacizumab, the MCP-1 level was significantly elevated. CONCLUSION: The significant associations of mCNV in highly myopic eyes with elevated levels of vascular endothelial growth factor or inflammatory cytokines and maculopathy lesions strongly suggest an involvement of inflammation in the etiology of mCNVs.
Asunto(s)
Humor Acuoso/metabolismo , Neovascularización Coroidal/metabolismo , Citocinas/metabolismo , Miopía Degenerativa/metabolismo , Anciano , Inhibidores de la Angiogénesis/uso terapéutico , Anticuerpos Monoclonales Humanizados/uso terapéutico , Bevacizumab , Neovascularización Coroidal/diagnóstico , Neovascularización Coroidal/tratamiento farmacológico , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Inyecciones Intravítreas , Masculino , Persona de Mediana Edad , Miopía Degenerativa/diagnóstico , Factor A de Crecimiento Endotelial Vascular/antagonistas & inhibidoresRESUMEN
Pharmacologic inhibitors of IκB kinase (IKK), especially IKK-ß, have been developed to treat inflammatory diseases. However, their interactions with components of the NF-κB pathways are not fully known in allergic diseases. To examine whether IKK is involved in immediate hypersensitivity reactions and to determine whether counterregulatory mechanisms in the NF-κB activation system were active, we examined the role played by IKK components on mast cell degranulation using a murine ocular immediate hypersensitivity reaction model. Pharmacologic inhibition of IKK in mice caused paradoxical aggravation of the mast cell-mediated immediate hypersensitivity reaction and up-regulation in the expression of inflammatory cytokines. Downstream analyses showed that B-cell deficiency or treatment by IL-1 receptor antagonist corrected the aberrant activation of tissue-resident mast cells, which would indicate contribution by activated B cells. Analyses of co-cultures of tissue-resident mast cells showed the contribution of activated B cells to activation of mast cells and secretion of inflammatory cytokines. Aberrant activation of the NF-κB promoter in isolated B cells was induced exclusively by IKK-ß inhibition and was negated by ablating IKK-α. Aggravated mast cell degranulation by pharmacologic IKK inhibition in the murine immediate hypersensitivity reaction was corrected by B-cell-targeted inhibition of IKK-α. Thus, IKK-ß limits B-cell-mediated mast cell activation and inflammatory cytokine induction in immediate hypersensitivity by counterbalancing the activity of IKK-α.
Asunto(s)
Linfocitos B/enzimología , Conjuntivitis Alérgica/enzimología , Quinasa I-kappa B/antagonistas & inhibidores , Mastocitos/enzimología , Animales , Antígenos de Plantas/administración & dosificación , Antígenos de Plantas/efectos adversos , Linfocitos B/efectos de los fármacos , Biomarcadores/metabolismo , Western Blotting , Conjuntivitis Alérgica/etiología , Conjuntivitis Alérgica/inmunología , Citocinas/metabolismo , Ensayo de Inmunoadsorción Enzimática , Quinasa I-kappa B/metabolismo , Mastocitos/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , FN-kappa B/metabolismo , Extractos Vegetales/administración & dosificación , Extractos Vegetales/efectos adversos , Inhibidores de Proteínas Quinasas/administración & dosificación , Inhibidores de Proteínas Quinasas/farmacología , Reacción en Cadena en Tiempo Real de la Polimerasa , beta-N-Acetilhexosaminidasas/metabolismoRESUMEN
Aiming at the application to photodynamic therapy, natural bacteriochlorophyll-a was converted to chemically stable free-base derivatives possessing different kinds of hydrophilic C17-propionate residues. These semi-synthetic bacteriochlorins were found to have self-assembling ability in an aqueous environment and formed stable J-type aggregates in a cell culture medium containing 0.2% DMSO. The electronic absorption spectra of all the sensitizers showed Qy absorption maxima at 754 nm in DMSO as their monomeric states, while a drastic shift of the red-most bands to ca. 880 nm was observed in the aqueous medium. The circular dichroism spectra in the medium showed much intense signals compared to those measured in DMSO, supporting the formation of well-ordered supramolecular structures. By introducing hydrophilic side chains, the bacteriochlorin sensitizers could be dispersed in the aqueous medium as their J-aggregates without the use of any surfactants. Cellular uptake efficiencies as well as photodynamic activities were evaluated using human cervical adenocarcinoma HeLa cells. Among the 11 photosensitizers investigated, the best result was obtained for a charged derivative possessing trimethylammonium terminal (17-CH2CH2COOCH2CH2N+(CH3)3I-) and photocytotoxicity of EC50 = 0.09 µM was achieved by far-red light illumination of 35 J/cm2 from an LED panel (730 nm).
RESUMEN
PURPOSE: To determine whether there is a significant association between inflammatory cytokines in the tear fluid and the severity of Retinopathy of Prematurity (ROP). STUDY DESIGN: Retrospective cohort study. METHODS: The cytokine levels in tear fluids were determined in 34 eyes with ROP and 18 eyes without ROP. There were 15 eyes with severe ROP requiring treatment and 19 eyes with mild ROP not requiring treatment. For severe ROP eyes, tear fluids were collected before treatment. RESULTS: Significantly higher levels of CCL2 and vascular endothelial growth factor (VEGF) were detected in eyes with severe ROP compared to eyes with mild ROP and no ROP. When assessed for cytokine levels that discriminate each disease group, CCL2 showed a significant odds ratio of 1.76 for severity change (/quintile, P = 0.032, after adjusting for birth weight). Correlation analysis showed that birth weight correlated with IL-1α levels, and decreased weight gain increased IFN-γ levels. We next determined tear fluid cytokines which discriminate severe ROP using receiver operating characteristics' analysis. We found that combination of higher CCL2 levels, higher VEGF levels, and lower IFN-γ levels in the tear fluid had a stronger predictive value for severe ROP (area under curve, 0.85). CONCLUSION: The levels of CCL2, VEGF, and IFN-γ in tear fluid may serve as useful biomarkers for assessing the severity of ROP.
RESUMEN
PURPOSE: To estimate the roles of extracellular vesicles (EVs) in tears and to determine whether their profiles are associated with the type of ocular disease. STUDY DESIGN: Cross-sectional study. METHODS: Tear EVs were extracted from 14 healthy participants and from 21 patients with retinal diseases (age-related macular degeneration [AMD] or diabetic macular edema [DME]). The surface marker expression of tear EVs was examined, and microRNAs (miRNAs) were extracted and profiled by use of real-time PCR array. The stability of the expression of the miRNAs was determined, and their functions were assessed by network analyses. Classification accuracy was evaluated by use of a random forest classifier and k-fold cross-validation. RESULTS: The miRNAs that were highly expressed in tear EVs were miR-323-3p, miR-548a-3p, and miR-516a-5p. The most stably expressed miRNAs independent of diseases were miR-520h and miR-146b-3p. The primary networks of the highly stably expressed endogenous miRNAs were annotated as regulation of organismal injury and abnormalities. The highly expressed miRNAs for severe retinal disease were miR-151-5p for AMD and miR-422a for DME, suggesting potential roles of tear EVs in liquid biopsy. Nine miRNAs (miR-25, miR-30d, miR-125b, miR-132, miR-150, miR-184, miR-342-3p, miR-378, and miR-518b) were identified as distinguishing individuals with AMD from healthy individuals with a classification accuracy of 91.9%. CONCLUSIONS: The finding that tear EVs contain characteristic miRNA species indicates that they may help in maintaining homeostasis and serve as a potential tool for disease diagnosis.
Asunto(s)
Retinopatía Diabética , Vesículas Extracelulares , Edema Macular , MicroARNs , Humanos , MicroARNs/genética , MicroARNs/metabolismo , Proyectos Piloto , Retinopatía Diabética/diagnóstico , Retinopatía Diabética/genética , Retinopatía Diabética/metabolismo , Estudios Transversales , Vesículas Extracelulares/genética , Vesículas Extracelulares/metabolismoRESUMEN
MXenes, a new family of 2D nanostructured materials, have been widely studied in the field of artificial photosynthesis due to their outstanding physicochemical properties. In this work, a series of 2,4-bis[4-(N,N-dibutylamino)phenyl] squaraine (SQ) derivatives with different number of hydroxyl groups were hybridized with Ti3C2Tx MXene nanosheets, and the organic-inorganic hybrid photocatalysts were applied for water-splitting hydrogen evolution. The mass ratios of SQ@Ti3C2Tx were optimized to 4 wt% for each SQ, and the best hydrogen evolution reaction (HER) rate of 28.6 µmol h-1 g-1 was achieved by SQ-3 with four OH groups. The photocatalytic ability of the hybrid comes from the outstanding light harvesting of SQ dye, sufficient active sites of Ti3C2Tx, and efficient separation and transfer of the photogenerated charges via heterojunction between SQ aggregates and Ti3C2Tx. This work firstly demonstrates an example of SQ sensitizer combined with MXene for hydrogen generation, which provides a new insight to further explore the MXene-based hybrid nanomaterials for water splitting hydrogen evolution.
Asunto(s)
Ciclobutanos , Titanio , HidrógenoRESUMEN
The purpose of this study was to identify the inflammatory cytokines that were associated with pachychoroid neovasculopathy (PNV). Seventy-five eyes of 75 patients with PNV, 145 eyes of 145 patients with neovascular age-related macular degeneration without pachyvessels, and 150 eyes of 150 normal subjects were examined for the levels of intraocular cytokines. In eyes with PNV, the levels of IL-1α, IL-1ß, IL-2, IL-4, IL-10, and VEGF were significantly higher than that of the controls. Logistic regression analysis showed that the highest association with the pachyvessels was found for IL-4, IL-2, and IL-1α. In eyes with PNV, the levels of IL-4, IL-2, IL-5, IL-13, IL-1α, and IL-1ß were significantly higher in eyes with both increased choroidal thickness and choroidal vessel diameter. The strongest correlation with the choroidal thickness and vessel diameter was observed for IL-4. In PNV eyes with polypoidal lesions, the levels of IL-4, IL-17, and TNFß were significantly correlated with the number of polypoidal lesions. Of these cytokines, IL-4 was especially associated with the thickness of the choroidal vessels and the formation of polypoidal lesions. We conclude that IL-4 is most likely involved in establishing the clinical characteristics of PNV and polypoidal vascular remodeling.
Asunto(s)
Neovascularización Coroidal , Interleucina-4 , Humanos , Coroides/irrigación sanguínea , Neovascularización Coroidal/patología , Citocinas , Angiografía con Fluoresceína , Interleucina-2 , Estudios Retrospectivos , Tomografía de Coherencia ÓpticaRESUMEN
In this study, we fabricated a photodetector (PD) with two types of chlorophyll derivatives, namely, zinc methyl 3-devinyl-3-hydroxymethyl-pyropheophorbide-a (ZnChl) and methyl 131-deoxo-131-dicyanomethylene-pyropheophorbide-a (H2Chl'), via a two-step drop-coating process. In the absorption range of ZnChl/H2Chl' films, the maximum external quantum efficiency of ZnChl/H2Chl'-based devices reached 1363% at -8 V and 1345% at 2.5 V, exhibiting the photomultiplication (PM) phenomenon. The PM phenomenon of ZnChl/H2Chl'-based devices is attributed to hole tunneling injection from the external circuit assisted by electron accumulation in the ZnChl and H2Chl' under light illumination. Through the investigation of the responsivity (R) of ZnChl/H2Chl'-based devices, it has been found that achieving a high R is easier under forward bias compared with reverse bias (7706 mA/W at -8 V and 7629 mA/W at 2.5 V). The organic PDs based on ZnChl/H2Chl' exhibit PM behavior, offering a promising approach to improve the device's responsivity.
RESUMEN
Methyl pheophorbide-a/a' derivatives covalently linked with oligomethylene chains at the 3-CH(2)OCO- and 13(2)-COO- moieties in a molecule were prepared by modifying chlorophyll-a through intramolecular ring-closing metathesis of vinyl groups. At least, a C10-length between the 3(3)- and 13(4)-positions was necessary for the cyclization and connection of a C12-strap was the most suitable to achieve the highest closure yield. The oligomethylene chain in 13(2) R-epimers derived from methyl pheophorbide-a covered the α-face of the chlorin π-plane and the strap in the corresponding 13(2) S-epimers protected the ß-face. Synthetic 13(2) R-epimer with a dodecamethylene chain gave a flat chlorin π-plane, while the decamethylene chain in the 13(2) R-epimer distorted the π-system due to its shorter linkage. The distortion by strapping in the 13(2) R-epimer induced a slight blue-shift of Qy peak in dichloromethane. CD spectra of the 13(2) R-epimers were similarly dependent on the chain length, i.e., the distortion of π-plane. Visible absorption and CD spectra of all the strapped 13(2) S-epimers were almost identical and only slightly different from those of the unstrapped. The strapping in the 13(2) S-epimers shifted the Qy peak bathochromically.
Asunto(s)
Clorofila/análogos & derivados , Spirulina/química , Clorofila/síntesis química , Clorofila/química , Clorofila A , Dicroismo Circular , Modelos Moleculares , Conformación Molecular , Óptica y Fotónica , Soluciones , Espectrofotometría Atómica , EstereoisomerismoRESUMEN
Ocular cytomegalovirus (CMV) infections in immunocompetent individuals are rare, but its activation can cause chronic and relapsing inflammation in anterior segment of the eye resulting in loss of corneal clarity and glaucoma. Fifty five patients with anterior segment CMV infection were assessed for their clinical characteristics, and CMV corneal endotheliitis was found to cause significant loss of corneal endothelial cells. The disease duration with recurrences was significantly correlated with the maximum intraocular level of CMV DNA. To examine why CMV is activated in healthy immunocompetent individuals and causing corneal endothelial cell damage, assays of cytotoxic T cells (CTLs) which directly target infected corneal endothelial cells were performed for 9 HLA-matched CMV corneal endotheliitis patients (HLA-A*2402). When the cell loss was analyzed for associations with CTL responses, CMV-induced endothelial cell damage was mitigated by pp65-specific CTL induction. The recurrence-free time was also prolonged by pp65-specific CTL induction (hazard ratio (HR): 0.93, P = 0.01). In contrast, IE1-specific CTL was associated with endothelial cell damage and reduced the time for corneal transplantation (HR: 1.6, P = 0.003) and glaucoma surgery (HR: 1.5, P = 0.001). Collectively, induction of pp65-specific CTL was associated with improved visual prognosis. However, IE1-specific CTL without proper induction of pp65-specific CTL can cause pathological damage leading to the need of surgical interventions.