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1.
Indian J Ophthalmol ; 2024 May 20.
Article in English | MEDLINE | ID: mdl-38767559

ABSTRACT

PURPOSE: To evaluate the effect of anterior-segment structure on vault and position after implantable collamer lens (ICL) implantation using ultrasound biomicroscopy. METHODS: The retrospective case-control study included insufficient vault eyes (<250 µm), ideal vault eyes (250-750 µm), and excessive vault eyes (>750 µm). The preoperative biometric parameters of the anterior-segment structure and basic data between the three groups were analyzed using one-way analysis of variance. RESULTS: There were significant differences ( P < 0.05) between the three groups in maximum ciliary body thickness (CBT max ), iris-zonule distance (IZD), and trabecular-ciliary angle (TCA). The vault gradually decreased as CBT max decreased and TCA increased. In the pairwise comparison, the CBT max comparison between the insufficient vault (<250 µm) group and the excessive vault (>750 µm) group was statistically significant ( P = 0.024, 95% CI: -0.17-0.017 µm); the TCA comparison between the insufficient vault (<250 µm) group and the excessive vault (>750 µm) group was statistically significant ( P = 0.005, 95% CI: 1.78°-12.15°); The IZD comparison between the insufficient vault (<250 µm) group and the excessive vault (>750 µm) group was statistically significant ( P = 0.037, 95% CI: 0.0027-0.1119 µm). The analysis of 284 ICL haptics locations showed that there were 16.67%, 32.69%, and 70.83% haptics located in the ciliary sulcus in three groups, respectively. CONCLUSION: The vault and ICL haptics position are related to anterior-segment structure. A thinner and posteriorly positioned ciliary body would increase the risk of low vault and fewer ICL haptics located in the ciliary sulcus after ICL implantation. This provides guidance for the selection of the ICL size and placement position before surgery.

2.
Int Ophthalmol ; 43(12): 4585-4593, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37665493

ABSTRACT

PURPOSE: To evaluate the safety of yttrium-aluminum-garnet (YAG) laser vitreolysis for intraocular tissues. METHODS: Thirty-six New Zealand rabbits were divided as follows: Group 1000 (n = 12) treated with YAG laser of 1000 mJ (5 mJ × 200 shots), Group 2000 (n = 12) treated with YAG laser of 2000 mJ (5 mJ × 400 shots), Group 3000 (n = 12) treated with YAG laser of 3000 mJ (5 mJ × 600 shots). Either a single eye was chosen as the study eye in study groups while the other was untreated as the control group. Intraocular pressure (IOP), slit-lamp, optical coherence tomography (OCT), transmission electron microscopy (TEM), and inflammatory cytokines of aqueous humor (interleukin-1α (IL-1α), interleukin-1ß (IL-1ß), interleukin-8 (IL-8), and tumor necrosis factor-α (TNF-α)) were performed to examine the rabbits. RESULTS: There were no abnormalities in the study groups of IOP, slit-lamp, and OCT examinations. Group 3000 of TEM showed: neutrophils and mitochondrial swelling on day 1, and fibroblasts and neocollagen on day 14. No abnormalities were observed in Group 1000 and 2000 of TEM. Levels of IL-1α and TNF-α increased at 12 h and decreased to baseline on day 3. Levels of IL-1ß increased at 12 h and decreased to baseline on day 7. Levels of IL-8 increased on day 1 and decreased to baseline on day 3. CONCLUSION: YAG laser vitreolysis is safe when the distance is more than 2 mm from ablation point to the lens and the retina, and the total energy is less than 2000 mJ for one treatment procedure.


Subject(s)
Eye Diseases , Laser Therapy , Lasers, Solid-State , Rabbits , Animals , Interleukin-8 , Tumor Necrosis Factor-alpha , Lasers, Solid-State/adverse effects , Eye Diseases/surgery , Vitrectomy , Laser Therapy/adverse effects , Laser Therapy/methods , Postoperative Complications/surgery , Retina
3.
Adv Mater ; 35(45): e2304711, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37548095

ABSTRACT

Metal halide perovskites (MHPs) are emerging photocatalyst materials that can enable sustainable solar-to-chemical energy conversion by virtue of their broad absorption spectra, effective separation/transport of photogenerated carriers, and solution processability. Although preliminary studies show the excellent photocatalytic activities of MHPs, their intrinsic structural instability due to the low formation energy and soft ionic nature is an open challenge for their practical applications. This review discusses the latest understanding of the stability issue and strategies to overcome this issue for MHP-based photocatalysis. First, the origin of the instability issue at atomic levels and the design rules for robust structures are analyzed and elucidated. This is then followed by presenting several different material design strategies for stability enhancement, including reaction medium modification, material surface protection, structural dimensionality engineering, and chemical composition engineering. Emphases are placed on understanding the effects of these strategies on photocatalytic stability as well as the possible structure-performance correlation. Finally, the possible future research directions for pursuing stable and efficient MHP photocatalysts in order to accelerate their technological maturity on a practical scale are outlined. With that, it is hoped to provide readers a valuable snapshot of this rapidly developing and exciting field.

4.
J Colloid Interface Sci ; 636: 11-20, 2023 Apr 15.
Article in English | MEDLINE | ID: mdl-36621125

ABSTRACT

Efficient and economic bifunctional electrocatalyst for water splitting to produce hydrogen is urgently required. The layered double hydroxides (LDHs) have shown superior activity for oxygen evolution reaction (OER) for water electrolysis, while their hydrogen evolution reaction (HER) activity remains challenging. Herein, we report an alkali hydrothermal-treatment strategy to enhance the HER as well as OER performance of NiCo-LDH. This method can create metal vacancies and newly formed Ni/Co(OH)2 phase over NiCo-LDH, tune the electronic structure, and improve the electrical conductivity, thereby improving the electrochemical activity. The NiCo-LDH-OH catalyst delivers a current density of 10 mA cm-2 at an overpotential of 180 mV for HER and an overpotential of 317 mV for OER, which is greatly reduced compared to the pristine NiCo-LDH (295 mV for HER and 336 mV for OER). When assembled into an electrolyzer both as a cathode and anode, it demonstrates superior activity for overall water splitting with no obvious decay after 20 h. This work paves a new path for fabricating efficient LDHs-based HER/OER bifunctional catalysts.

5.
Exp Eye Res ; 218: 109014, 2022 05.
Article in English | MEDLINE | ID: mdl-35245515

ABSTRACT

Age-related macular degeneration (AMD) is the main cause of blindness in elderly individuals. As a metabolic regulator, fibroblast growth factor 21 (FGF-21) has been proven indicated to have an effect on wet AMD, but whether this cytokine has a therapeutic effect on dry AMD is unclear. The current study aimed to evaluate the preventive effects of FGF-21 against retinal degeneration in mice and provide mechanistic insights. FGF-21-/- mice were raised to 10 months of age. Then, the morphological changes in the retinal pigment epithelium (RPE)/choroid of the mice were observed by transmission electron microscopy (TEM), and iTRAQ was used to detect the variations in the protein profile. Next, FGF-21-/- and wild-type mice of the same age were fed hydroquinone to generate a dry AMD mouse model to examine whether exogenous FGF-21 can interfere with the occurrence and development of dry AMD. In vivo studies revealed that following FGF-21 knockout, there was an increase in the expression of complement in the RPE/choroid concomitant with the occurrence of dry AMD-like pathological changes. Furthermore, exogenous FGF-21 administration effectively reversed this phenomenon. FGF-21 also demonstrated strong anti-inflammatory effects in the RPE/choroid by inhibiting the NF-κB pathway. In conclusion, the present study demonstrates that FGF-21 treatment presents a novel therapeutic approach for the prevention and development of dry AMD by reducing complement.


Subject(s)
Geographic Atrophy , Wet Macular Degeneration , Animals , Fibroblast Growth Factors , Geographic Atrophy/pathology , Geographic Atrophy/prevention & control , Mice , Retinal Pigment Epithelium/metabolism , Wet Macular Degeneration/pathology
6.
Dalton Trans ; 50(45): 16578-16586, 2021 Nov 23.
Article in English | MEDLINE | ID: mdl-34739538

ABSTRACT

Exploring efficient bifunctional electrocatalysts is of great importance for water splitting to obtain scalable and sustainable hydrogen generation. The strategy of element modification is effective for tuning the electronic structures of electrocatalysts. Herein, binder-free, phosphorus-doped NiCo2S4/CFP (Ni-Co-S-P) was synthesized under hydrothermal conditions, followed by surface phosphorization via solid reaction. The incorporation of P modulates the electronic structure of the Ni-Co-S-P catalyst, increases the electrical conductivity, and promotes the electrochemical surface area and the number of active sites, thereby improving its activity. The Ni-Co-S-P catalyst delivers a current density of 10 mA cm-2 at an overpotential of 176 mV for the hydrogen evolution reaction (HER) and an overpotential of 265 mV for the oxygen evolution reaction (OER). When assembled into an electrolyzer both as a cathode and anode, it demonstrated outstanding activity for overall water splitting to afford a potential of 1.76 V at 10 mA cm-2 with no obvious decay after 25 h.

7.
Small ; 17(43): e2102408, 2021 10.
Article in English | MEDLINE | ID: mdl-34337868

ABSTRACT

The catalysts for low-temperature selective catalytic reduction of NO with NH3 (NH3 -SCR) are highly desired due to the large demand in industrial furnaces. The characteristic of low-temperature requires the catalyst with rich active sites especially the redox sites. Herein, the authors obtain oxygen defect-rich ß-MnO2 from a crystal phase transformation process during air calcination, by which the as-prepared γ-MnO2 nanosheet and nanorod can be conformally transformed into the corresponding ß-MnO2 . Simultaneously, this transformation accompanies oxygen defects modulation resulted from lattice rearrangement. The most active ß-MnO2 nanosheet with plentiful oxygen defects shows a high efficiency of > 90% NO conversion in an extremely wide operation window of ≈120-350 °C. The detailed characterizations and density functional theory (DFT) calculations reveal that the introduction of oxygen defects enhances the adsorption properties for reactants and decreases the energy barriers of *NH2 formation more than 0.3 eV (≈0.32-0.37 eV), which contributes to a high efficiency of low-temperature SCR activity. The authors finding provides a feasible approach to achieve the oxygen defect engineering and gains insight into manganese-based catalysts for low-temperature NO removal or pre-oxidation.


Subject(s)
Manganese Compounds , Oxygen , Ammonia , Catalysis , Oxidation-Reduction , Oxides
8.
Invest Ophthalmol Vis Sci ; 62(2): 14, 2021 02 01.
Article in English | MEDLINE | ID: mdl-33591357

ABSTRACT

Purpose: Besides regulating paracellular diffusion, claudin-19 modulates the expression of proteins essential for the retinal pigment epithelium (RPE). This study asks how RPE responds when the expression of claudin-19 is reduced. Methods: In stem cell-derived RPE, claudin-19 and sequestosome-1/p62 (SQSTM1) were knocked down with siRNAs. Expression was monitored by quantitative RT-PCR and western blotting. Morphology and function were monitored by immunocytochemistry and transepithelial electrical resistance (TER). Phagocytosis of photoreceptor outer segments (POSs) was followed by fluorescence-activated cell sorting and western blotting. Pharmacology was used to assess the effects of AMP-activated protein kinase (AMPK) and SQSTM1 on phagocytosis. Enzymatic activity was measured using commercial assay kits. Results: Knockdown of claudin-19 reduced the TER without affecting the integrity of the apical junctional complex, as assessed by the distribution of zonula occludens-1 and filamentous actin. AMPK was activated without apparent effect on autophagy. Activation of AMPK alone had little effect on phagocytosis. Without affecting ingestion, knockdown reduced the rate of POS degradation and increased the steady-state levels of LC3B and SQSTM1. Proteasome inhibitors also retarded degradation, as did knockdown of SQSTM1. The expression of metallothioneins and the activity of superoxide dismutase increased. Conclusions: Knockdown of claudin-19 slowed the degradation of internalized POSs. The study questions the role of activated AMPK in phagocytosis and suggests a role for SQSTM1. Further, knockdown was associated with a partial oxidative stress response. The study opens new avenues of experimentation to explore these essential RPE functions.


Subject(s)
Claudins/genetics , Gene Expression Regulation , RNA/genetics , Retinal Diseases/genetics , Retinal Pigment Epithelium/metabolism , Sequestosome-1 Protein/genetics , Blotting, Western , Cell Line , Claudins/metabolism , Gene Knockdown Techniques , Humans , Immediate-Early Proteins , Immunohistochemistry , Microscopy, Confocal , Phagocytosis , Retinal Diseases/metabolism , Retinal Diseases/pathology , Retinal Pigment Epithelium/pathology , Sequestosome-1 Protein/biosynthesis
9.
J Ophthalmol ; 2021: 8857715, 2021.
Article in English | MEDLINE | ID: mdl-33510907

ABSTRACT

PURPOSE: To report a technique for performing sutureless intrascleral fixation of a posterior chamber intraocular lens (PC-IOL) and analyzing the clinical outcomes and postoperative complications. Study Design. 68 eyes of 66 patients who received the technique were studied retrospectively. METHODS: The best-corrected visual acuity (BCVA), intraocular pressure (IOP), anterior chamber depth (ACD), IOL tilt and decentration, corneal topography (K1 and K2), and postoperative complications were determined at 3 months. RESULTS: The mean preoperative BCVA was 1.63 ± 1.24 logMAR units, and the mean postoperative BCVA was 0.74 ± 0.59 logMAR units at 3 months (P < 0.05). The mean preoperative IOP was 21.9 ± 12.6 mmHg, and the mean postoperative IOP was 16.9 ± 4.5 mmHg at 3 months (P = 0.001). The mean preoperative corneal topography (K1 and K2) was K1 = 42.14 ± 1.91 and K2 = 43.54 ± 1.51; the mean postoperative corneal topography (K1 and K2) was K1 = 43.03 ± 2.18 and K2 = 43.40 ± 1.71 at 3 months (P = 0.678 and 0.468, respectively). The mean preoperative spherical equivalent was +11.00 ± 13.19 diopters (D), and the mean postoperative spherical equivalent was +0.06 ± 0.86 D (P < 0.005). The mean IOL tilt was 2.4 ± 1.7°, and the mean decentration was 0.35 ± 0.21 mm. The mean ACD was 4.31 ± 0.29 mm. CONCLUSIONS: The 27-gauge sutureless intrascleral PC-IOL implantation technique minimizes intraoperative injury, simplifies procedure, and provides good PC-IOL fixation with few postoperative complications.

10.
Angew Chem Int Ed Engl ; 59(49): 22156-22162, 2020 Dec 01.
Article in English | MEDLINE | ID: mdl-32803819

ABSTRACT

Quasi-two-dimensional (2D) perovskites are promising candidates for light generation owing to their high radiative rates. However, strong exciton-phonon interactions caused by mechanical softening of the surface act as a bottleneck in improving their suitability for a wide range of lighting and display applications. Moreover, it is not easily available to tune the phonon interactions in bulk films. Here, we adopt bottom-up fabricated blue emissive perovskite nanoplatelets (NPLs) as model systems to elucidate and as well as tune the phonon interactions via engineering of binary NPL solids. By optimizing component domains, the phonon coupling strength can be reduced by a factor of 2 driven by the delocalization of 2D excitons in out-of-plane orientations. It shows the picosecond energy transfer originated from the Förster resonance energy transfer (FRET) efficiently competes with the exciton-phonon interactions in the binary system.

11.
Exp Eye Res ; 198: 108157, 2020 09.
Article in English | MEDLINE | ID: mdl-32712183

ABSTRACT

Claudin-19 is the major claudin in the tight junctions of the retinal pigment epithelium (RPE). Claudin-3 is also uniformly expressed albeit in lesser amounts. Besides modulating transepithelial diffusion, claudins modulate gene expression. The absence of claudin-19 and claudin-3 in the RPE cell lines, ARPE-19 and hTERT-RPE-1, provide an opportunity to examine whether exogenous claudins regulate gene expression in the absence of tight junctions. Quantitative RT-PCR was used to compare gene expression in ARPE-19 and hTERT-RPE-1 with that of highly differentiated, human fetal RPE. Claudin-19 and claudin-3 were exogenously expressed using an adenoviral vector. The transepithelial electrical resistance (TER) was measured using Endohm electrodes, and the effects of claudin on the actin cytoskeleton were determined by immunocytochemistry. The effect of claudin on gene expression was examined by quantitative RT-PCR and western blotting. Aside from claudin-19 and claudin-3, ARPE-19 and hTERT-RPE-1 expressed most junction-associated mRNAs in amounts comparable to human fetal RPE, but some RPE signature and maturation genes were under-expressed. Unlike ARPE-19, hTERT-RPE-1 failed to form tight junctions or develop a TER. Claudins exogenously expressed in hTERT-RPE-1 failed to crystalize an apical junctional complex. Actin filaments were not redistributed from stress fibers to cortical bands, and a TER was not established. In hTERT-RPE-1, claudins were found only in internal vesicular-like structures. Nonetheless, claudins increased the expression of the mRNAs for a collection of RPE-enriched proteins. Claudin-19 and claudin-3 had different effects on gene and protein expression indicating activation of overlapping, but distinct, signaling pathways. A major difference was the ability of claudin-19 to affect steady-state levels of ADAM9 and tyrosinase in ARPE-19. In conclusion, claudins can increase the barrier function of a pre-existing apical junctional complex, but on its own it cannot recruit tight junction proteins to form a complex de novo. Many effects of claudin on gene expression did not require an association with the apical junctional complex. Although claudin-19 shared many effects with claudin-3, claudin-19 exerted unique effects on the maturation of RPE.


Subject(s)
Claudins/genetics , Gene Expression , Membrane Proteins/genetics , RNA, Messenger/genetics , Retinal Pigment Epithelium/metabolism , Blotting, Western , Cells, Cultured , Claudins/biosynthesis , Humans , Membrane Proteins/biosynthesis , Retinal Pigment Epithelium/cytology , Tight Junctions/metabolism
12.
ACS Appl Mater Interfaces ; 12(28): 31863-31874, 2020 Jul 15.
Article in English | MEDLINE | ID: mdl-32567298

ABSTRACT

Metal-halide perovskite-based green and red light-emitting diodes (LEDs) have witnessed a rapid development because of their facile synthesis and processability; however, the blue-band emission is constrained by their unstable chemical properties and poorly conducting emitting layers. Here, we show a trioctylphosphine oxide (TOPO)-mediated one-step approach to realize bright deep-blue luminescent FAPbBr3 nanoplatelets (NPLs) with enhanced stability and charge transport. The concentration of NPL surface ligands is shown to be progressively tuned via varying the amount of intermediate TOPO due to the acid-base equilibrium between protic acid and TOPO. By effectively optimizing the concentration of surface ligands, the structural integrity of NPL solids can be preserved in ambient air for a week, mainly because of the highly ordered and dense solid assembly and the reduced defects. The removal of excess organic ligands also enables the improvement of charge mobility by orders of magnitude. Ultimately, ultrapure deep-blue perovskite LEDs (439 nm) with a narrow emission width of 14 nm and a peak EQE of 0.14% are achieved at low driving voltage. Our finding expands the current understanding of surface ligand modulation in the development of pure bromide deep-blue perovskite optoelectronics.

13.
J Phys Chem Lett ; 10(23): 7516-7522, 2019 Dec 05.
Article in English | MEDLINE | ID: mdl-31729223

ABSTRACT

ZnxCd1-xSe is regarded as a promising semiconducting material for optoelectronic devices. However, the tunable amplified spontaneous emission (ASE) properties and corresponding charge carrier recombination dynamics in ZnxCd1-xSe (0 ≤ x ≤ 1) nanowires (NWs) remain poorly understood. Herein, the charge carrier dynamics and ASE properties in ZnxCd1-xSe NWs were systematically investigated. In these NWs, the one/two-photon pumped ASE wavelength across the entire visible spectrum (480-725 nm) can be easily tuned via compositional engineering. The ASE threshold is closely related to the absorption coefficient and PL lifetime. At room temperature, free-carrier recombination is dominated in the low fluence pumped PL process. The ASE behavior is determined by exciton recombination in the high pump fluence (>1018 cm-3) region. These findings uncover the origin of the tunable PL/ASE properties in ZnxCd1-xSe NWs and establish them as having practical application as a series of lasing gain materials.

14.
J Ophthalmol ; 2019: 7202731, 2019.
Article in English | MEDLINE | ID: mdl-31687201

ABSTRACT

PURPOSE: To describe the clinical features of combined central retinal artery and vein occlusion (CCRAVO). METHODS: This retrospective study included 33 admitted patients (33 eyes) who had CCRAVO. Clinical data, such as age, gender, best-corrected visual acuity (BCVA), intraocular pressure (IOP), findings on fundus color photography and fundus fluorescein angiography (FFA), and information about follow-up, were collected and analyzed. RESULTS: The age of the patients with CCRAVO ranged from 22 to 78 years, with a mean of 48.8 ± 14.1 years. At presentation, BCVA of the involved eyes ranged from no light perception (NLP) to 20/20. In addition, 45.5% (15/33) of the eyes had BCVA of finger counting (FC) or below, whereas 12.1% (4/33) had BCVA of 20/60 or above. The IOP was lower in the involved eyes than in the fellow eyes (15.0 ± 3.0 mmHg vs. 16.4 ± 2.3 mmHg, p=0.03). Ophthalmoscopic examination showed changes in both central retinal artery occlusion (CRAO) and central retinal vein occlusion (CRVO), including retinal hemorrhage, retinal ischemic whitening, optic disc hyperemia and/or edema, venous dilation and tortuosity, cotton wool spot (CWS), and Roth's spot. FFA showed prolonged arm-to-retina time (ART) and retinal arteriovenous passage time (RAP) (17.1 ± 4.9 s and 12.1 ± 8.8 s, respectively). Capillary nonperfusion (CNP) was seen in 21 eyes (63.6%), and in 14 (42.2%) of these, CNP was larger than 10 disc areas. At 2 to 3 weeks after presentation, BCVA improved in 23 eyes (71.9%) and further deteriorated in 5 eyes (15.6%). Retinal ischemic whitening improved in more than half of the eyes, whereas retinal hemorrhage increased in nearly half of the eyes. Follow-up ranged from 6 to 56 months. Seven patients were lost to follow-up. At final follow-up, six eyes had a visual acuity of 20/60 or greater, but 6 eyes had FC or worse. Four eyes developed neovascularization on follow-up. CONCLUSION: CCRAVO is a sight-threatening entity. Manifestations of CRAO and CRVO can be seen simultaneously in the early stage of disease, and CRVO may play a more important role in the development of CCRAVO.

15.
Commun Biol ; 2: 113, 2019.
Article in English | MEDLINE | ID: mdl-30937396

ABSTRACT

Mutations of claudin-19 cause Familial Hypomagnesaemia and Hypercalciuria, Nephrocalcinosis with Ocular Involvement. To study the ocular disease without the complications of the kidney disease, naturally occurring point mutations of human CLDN19 were recreated in human induced pluripotent cells or overexpressed in the retinae of newborn mice. In human induced pluripotent cells, we show that the mutation affects retinal neurogenesis and maturation of retinal pigment epithelium (RPE). In mice, the mutations diminish the P1 wave of the electroretinogram, activate apoptosis in the outer nuclear layer, and alter the morphology of bipolar cells. If mice are given 9-cis-retinal to counter the loss of retinal isomerase, the P1 wave is partially restored. The ARPE19 cell line fails to express claudin-19. Exogenous expression of wild type, but not mutant claudin-19, increases the expression of RPE signature genes. Mutated claudin-19 affects multiple stages of RPE and retinal differentiation through its effects on multiple functions of the RPE.


Subject(s)
Claudins/genetics , Disease Susceptibility , Mutation , Neurogenesis/genetics , Retina/metabolism , Vision, Ocular/genetics , Animals , Cell Differentiation , Cells, Cultured , Claudins/chemistry , Disease Models, Animal , Gene Expression , Genes, Reporter , Humans , Mice , Retinal Degeneration/genetics , Retinal Degeneration/metabolism , Retinal Degeneration/physiopathology , Retinal Pigment Epithelium/metabolism
16.
Biomaterials ; 154: 158-168, 2018 Feb.
Article in English | MEDLINE | ID: mdl-29128844

ABSTRACT

Retinal degeneration is a leading cause of blindness in developed countries. Stem cells can be differentiated into retinal organoids to study mechanisms of retinal degeneration, develop therapeutic agents, and potentially serve as replacement tissues. The spherical nature of these retinoids limits their utility, because the investigator lacks ready access to both sides of the neo-tissue. For tissue-replacement, spherical retinoids are unable to interact simultaneously with the host retinal pigment epithelium and remaining neurosensory retina. To attempt making a planar retinoid, we developed a biodegradable scaffold that simulates the extracellular matrix of the neurosensory retina. Human embryonic stem cells were seeded on the scaffold. Differentiation into retinal cells was confirmed by quantitative RT-PCR, confocal immunocytochemistry, and immunoblotting. The scaffold favored differentiation into retinal cell types over other anterior forebrain cells, but retinal lamination was rudimentary. The cultures elicited a minimal immune response when implanted into the subretinal space of a mouse model of retinal degeneration. The implants survived for at least 12 weeks, but there was evidence of cytoplasmic transfer rather than implantation into the outer nuclear layer (photoreceptor layer). However, some implanted cells migrated to the inner layers of the retina and established elaborate arbors of neurites.


Subject(s)
Biocompatible Materials/pharmacology , Cell Differentiation , Human Embryonic Stem Cells/cytology , Retina/cytology , Tissue Scaffolds/chemistry , Animals , Biomarkers/metabolism , Cell Adhesion/drug effects , Cell Differentiation/drug effects , Cell Proliferation/drug effects , Embryoid Bodies/metabolism , Fishes , Human Embryonic Stem Cells/drug effects , Humans , Mice , Retinal Degeneration/pathology , Retinal Degeneration/therapy
17.
Biochem Biophys Res Commun ; 495(1): 1516-1521, 2018 01 01.
Article in English | MEDLINE | ID: mdl-29197576

ABSTRACT

Neferine, an alkaloid isolated from Lotus seeds, displays multiple pharmacological effects that counter cancer, oxidants, and arrhythmia. It was initially identified as a strong inducer for macroautophagy in cancer cells by suppressing AMPK/mTOR signaling. In this study, we found that autophagy signaling was inhibited in the condition of neferine treatment. Exposure to neferine resulted in the accumulation of LC3-II and an associated adaptor protein, p62/SQSTM1. Knockdown of ATG5 failed to reduce the accumulation of LC3-II induced by neferine. The electron microscopy (EM) images showed that neferine induce accumulation of multi-vesicle bodies (MVB) and failure of lysosome maturation. Moreover, exposure to neferine reduced maturation of cathepsin D and impaired the degradation of autophagic and phagocytic cargos. Rather than stimulate autophagic flux, the data indicate that neferine impaired lysosomes to block degradation within phagolysosomes.


Subject(s)
Autophagy/drug effects , Autophagy/physiology , Benzylisoquinolines/administration & dosage , Lysosomes/physiology , Lysosomes/ultrastructure , Microtubule-Associated Proteins/metabolism , Antioxidants/administration & dosage , Dose-Response Relationship, Drug , HEK293 Cells , HeLa Cells , Humans , Lysosomes/drug effects , Metabolic Flux Analysis
18.
Nanoscale ; 9(40): 15612-15621, 2017 Oct 19.
Article in English | MEDLINE | ID: mdl-28990611

ABSTRACT

Key to optimizing and tailoring the optoelectronic properties of semiconductor nanostructures for practical applications is a clear understanding of their carrier interactions and recombination dynamics. Herein, the electron-hole (e-h) plasma dynamics and the electron-phonon coupling interactions in zincblende ZnTe nanowires (NWs) were systematically investigated by time-resolved photoluminescence (TRPL) spectroscopy over a wide range of lattice temperatures (4-300 K) and pump densities. Following intense, non-resonant femtosecond (fs) laser pulse excitation, the excited carriers thermalize to quasi-equilibrium distribution through carrier-carrier and carrier-phonon scattering within a few picoseconds. The peak temperature of the hot electron gas (Te0) is much higher than the lattice temperature and increases sub-linearly with the pump fluence. The hot electron gas thermalizes in two characteristic carrier density-dependent regimes - i.e., within 35 ps under high carrier densities (e-h plasma) while persisting to 360 ps under low carrier densities (exciton). Temperature-dependent studies of the ZnTe NWs revealed that the acoustic phonons play a significant role in the cooling of the hot e-h plasma in these NWs and the emission band broadening arises from the interplay of the contributions from crystal imperfections, LA and LO phonon scattering and most importantly, from the hot carrier thermalization. For demonstration, e-h plasma-amplified spontaneous emission in ZnTe NWs at room temperature by one- and two-photon excitation was realized. The results provide new insights into carrier interactions and recombination dynamics of ZnTe NWs and highlight their potential for high-efficiency e-h plasma light emitters, sensors and in plasma photochemotherapy.

19.
Nanotechnology ; 27(50): 505404, 2016 12 16.
Article in English | MEDLINE | ID: mdl-27875337

ABSTRACT

We present a facile method for the fabrication of hematite nanocrystal-carbon cloth (Fe2O3-CC) composite. Hierarchical manganite is chosen as the sacrificial precursor, that does not contribute to the component of final iron oxide but can be in situ dissolved by the acid produced from the Fe3+ hydrolysis. This method effectively enhances the specific surface area and conductivity of hematite (Fe2O3) by attaching Fe2O3 nanocrystals (around 5 nm) firmly on the surface of carbon fibers. The obtained Fe2O3-CC can be directly used as a binder-free electrode for a supercapacitor. Interestingly, the composite electrode exhibits synergistic electrochemical capacitance (electrochemical double-layer capacitance and pseudo-capacitance). It manifests a very high areal capacitance of 1.66 F cm-2 (1660 F g-1) at 2 mA cm-2 and excellent cycling performance at large current densities (88.6% retention at 30 mA cm-2 after 5000 cycles) in a three-electrode testing system, which is among the best performances reported in the literature. Importantly, when fabricated as a solid-state flexible symmetric supercapacitor it still shows a maximum energy density of 8.74 mW h cm-3 and power density of 253.9 mW cm-3. Additionally, its good flexibility makes it suitable for portable devices.

20.
Exp Eye Res ; 151: 179-89, 2016 10.
Article in English | MEDLINE | ID: mdl-27593915

ABSTRACT

Mutations of claudin-19 cause severe ocular deficits that are not easily reconciled with its role in regulating the outer blood retinal barrier. ARPE-19 is a widely used culture model of the retinal pigment epithelium (RPE). ARPE-19 is unique among epithelial cell lines, because it expresses all tight junction proteins except claudin family members. ARPE-19 also loses aspects of the RPE phenotype with cell passage. This study asks whether exogenous expression of the main RPE claudins, claudin-3 and claudin-19, would restore RPE phenotype, and whether these claudins have distinct roles in RPE. An Ussing chamber was used to measure the transepithelial electrical resistance and transepithelial electrical potential. These measurements were used to estimate the permeability co-efficients of ions. The transepithelial diffusion of polyethylene glycols were used to examine the leak pathway of tight junctions. Wound-healing, quantitative RT-PCR and immunoblotting examined diverse aspects of the RPE phenotype. Over-expression of either claudin decreased the permeability of small ions and polyethylene glycol. Both claudins were slightly cation-specific, but claudin-3 was less permeable to large solutes. Claudin expression widely affected gene expression to partially restore RPE phenotype. Claudins redistributed filamentous actin from stress fibers to circumferential bands associated with tight junctions, and made wound-healing more epithelial-like. Both claudins increased the expression of genes related to RPE core functions and increased steady-state levels of phosphorylated-AKT. In conclusion, claudin-3 and claudin-19 formed general permeability barriers and affected cell morphology, proliferation, migration, AKT signaling, and gene expression. When claudins are exogenously expressed, ARPE-19 more closely model native RPE.


Subject(s)
Claudin-3/genetics , Claudins/genetics , Gene Expression Regulation , RNA, Messenger/genetics , Retinal Diseases/genetics , Retinal Pigment Epithelium/metabolism , Tight Junctions/genetics , Cells, Cultured , Claudin-3/biosynthesis , Claudins/biosynthesis , Humans , Immunoblotting , Microscopy, Confocal , Phenotype , Retinal Diseases/metabolism , Retinal Diseases/pathology , Retinal Pigment Epithelium/cytology , Reverse Transcriptase Polymerase Chain Reaction , Tight Junctions/metabolism
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