Optimization of Self-Cleaning Thin-Film Layer for Photovoltaic Applications.

To improve the productivity of a photovoltaic (PV) module, TiO2 thin films of different thicknesses were applied as a self-cleaning layer on soda-lime glass and a Si PV module by spray-coating a TiO2 solution. The structural, optical, and wettability characteristics of the TiO2 thin films were investigated with respect to the thickness. Thermogravimetric-differential thermal analysis, X-ray diffraction, field-emission scanning electron microscopy, contact-angle analysis, ultraviolet-visible spectroscopy, atomic force microscopy, Fourier transform infrared spectroscopy, and a solar simulator were used to analyze the prepared TiO2 thin films. The optimal thickness was determined to be 100 nm. The TiO2 thin film exhibited a self-cleaning ability even after post-annealing at 250 °C. After the self-cleaning ability was confirmed, the TiO2 thin film was applied to the PV module.

Clinical Outcomes of an Optimized Prolate Ablation Procedure for Correcting Residual Refractive Errors Following Laser Surgery.

PURPOSE: The purpose of this study was to investigate the clinical efficacy of an optimized prolate ablation procedure for correcting residual refractive errors following laser surgery. METHODS: We analyzed 24 eyes of 15 patients who underwent an optimized prolate ablation procedure for the correction of residual refractive errors following laser in situ keratomileusis, laser-assisted subepithelial keratectomy, or photorefractive keratectomy surgeries. Preoperative ophthalmic examinations were performed, and uncorrected distance visual acuity, corrected distance visual acuity, manifest refraction values (sphere, cylinder, and spherical equivalent), point spread function, modulation transfer function, corneal asphericity (Q value), ocular aberrations, and corneal haze measurements were obtained postoperatively at 1, 3, and 6 months. RESULTS: Uncorrected distance visual acuity improved and refractive errors decreased significantly at 1, 3, and 6 months postoperatively. Total coma aberration increased at 3 and 6 months postoperatively, while changes in all other aberrations were not statistically significant. Similarly, no significant changes in point spread function were detected, but modulation transfer function increased significantly at the postoperative time points measured. CONCLUSIONS: The optimized prolate ablation procedure was effective in terms of improving visual acuity and objective visual performance for the correction of persistent refractive errors following laser surgery.

Electrical and Optical Properties of Hydrogen Doped Aluminum-Doped Zinc Oxide Thin Films for Low Cost Applications.

Aluminum-doped zinc oxide (AZO) thin films were prepared on glass substrate using a magnetron sputtering system. In this work, a powder target was used as a source material for low cost applications, instead of a conventional sintered ceramic target. The effects of the hydrogen gas ratio on the electrical and optical properties of the AZO films. The hydrogen doped AZO (AZO:H) films had a hexagonal polycrystalline structure. A small amount of hydrogen gas deteriorated the electrical and optical properties of the AZO:H films. However, these properties improved, as the H2/(H2 + Ar) gas ratio increased. The AZO:H films grown at an H2/(H2+Ar) ratio of 10% showed good properties for low cost applications, such as a low resistivity of 1.35 x 10(-3) Ω-cm, high average transmittance of 83.1% in the visible range of light.

Influence of Oxygen Gas Ratio on the Properties of Aluminum-Doped Zinc Oxide Films Prepared by Radio Frequency Magnetron Sputtering.

Aluminum-doped zinc oxide (AZO) thin films were deposited on glass and polyimide substrates using radio frequency magnetron sputtering. We investigated the effects of the oxygen gas ratio on the properties of the AZO films for Cu(In,Ga)Se2 thin-film solar cell applications. The structural and optical properties of the AZO thin films were measured using X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and UV-Visible-NIR spectrophotometry. The oxygen gas ratio played a crucial role in controlling the optical as well as electrical properties of the films. When oxygen gas was added into the film, the surface AZO thin films became smoother and the grains were enlarged while the preferred orientation changed from (0 0 2) to (1 0 0) plane direction of the hexagonal phase. An improvement in the transmittance of the AZO thin films was achieved with the addition of 2.5-% oxygen gas. The electrical resistivity was highly increased even for a small amount of the oxygen gas addition.

Gr-1intCD11b+ myeloid-derived suppressor cells accumulate in corneal allograft and improve corneal allograft survival.

We identified the characteristics of myeloid-derived suppressor cells (MDSCs) and investigated their mechanism of induction and their functional role in allograft rejection using a murine corneal allograft model. In mice, MDSCs coexpress CD11b and myeloid differentiation antigen Gr-1. Gr-1+CD11b+ cells infiltrated allografted corneas between 4 d and 4 wk after surgery; however, the frequencies of Gr-1+CD11b+ cells were not different between accepted and rejected allografts or in peripheral blood or BM. Of interest, Gr-1intCD11b+ cells, but not Gr-1hiCD11b+ cells, infiltrated the accepted graft early after surgery and expressed high levels of immunosuppressive cytokines, including IL-10, TGF-ß, and TNF-related apoptosis-inducing ligand. This population remained until 4 wk after surgery. In vitro, only high dose (>100 ng/ml) of IFN-γ plus GM-CSF could induce immunosuppressive cytokine expression in Gr-1intCD11b+ cells. Furthermore, adoptive transfer of Gr-1intCD11b+ cells reduced T cell infiltration, which improved graft survival. In conclusion, high-dose IFN-γ in allograft areas is essential for development of Gr-1intCD11b+ MDSCs in corneal allografts, and subtle environmental changes in the early period of the allograft can result in a large difference in graft survival.

Growth and characterization of CdS thin films on polymer substrates for photovoltaic applications.

In this work, cadmium sulfide (CdS) films were deposited on flexible polymer substrates such as polycarbonate (PC) and polyethylene terephthalate (PET). The r.f. magnetron sputtering, which is cost-effective scalable technique, was used for the film deposition. The structural and optical properties of the films grown at different sputtering pressures were investigated. When the CdS film was deposited at lower pressure, the crystallinity and the preferred orientation toward c-axis in hexagonal phase was improved. However, the optical transmittance was reduced as the sputtering pressure was decreased. Compared with the glass substrate, CdS films grown on polymer substrates were exhibited some wore structural and optical characteristics. CdTe thin film solar cell applied to sputtered CdS as a window layer showed a maximum efficiency of 11.6%.

Cellular death mediated by nuclear factor kappa B (NF-kappaB) translocation in cultured human lens epithelial cells after ultraviolet-B irradiation.

PURPOSE: To determine the role of nuclear factor kappa B (NF-kappaB) in the death of lens epithelial cells (LECs) after ultraviolet (UV) irradiation. SETTING: Department of Ophthalmology, Ilsan Paik Hospital, Inje University, Korea. METHODS: Cultures of simian virus 40 transfected human LECs (HLE B-3 cells) were were irradiated with a UVB source (312 nm) located 10 cm from the bottom of the slides for 1, 2, 3, or 4 minutes. Cytotoxicity was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide method. Translocation of NF-kappaB was examined by immunocytochemistry using anti-NF-kappaB p65 antibody and electrophoretic mobility shift assay (EMSA). Sulfasalazine, a specific NF-kappaB inhibitor, was used to confirm the role of NF-kappaB by pretreating samples for 30 minutes before UV irradiation, after which cytotoxicity and NF-kappaB translocation were evaluated. RESULTS: When HLE B-3 cells were irradiated with UVB, translocation of NF-kappaB was observed with immunocytochemistry. These translocations peaked during EMSA 6 hours after UV irradiation. In HLE B-3 cells pretreated with sulfasalazine, the translocation of NF-kappaB was blocked. Cellular death after UV irradiation was also markedly reduced by sulfasalazine pretreatment. Ultraviolet irradiation can translocate NF-kappaB, and sulfasalazine is a useful blocking agent in this pathway. In this experimental model, sulfasalazine prevented cellular death after UV irradiation. CONCLUSION: The findings suggest that NF-kappaB plays an important role in cellular death after UV irradiation.

Accumulation and aberrant modifications of alpha-crystallins in anterior polar cataracts.

Crystallins are the major proteins found in the lens, and the localization of specific crystallins is well known. Overexpression and accumulation of alphaB-crystallin has been observed in response to stress conditions or in certain diseases, such as brain tumors and neurodegenerative diseases. The purpose of this study was to examine whether alpha-crystallins are modified during pathological myofibroblastic changes in lens epithelial cells. Lens epithelial cells attached to the anterior capsules of patients with nuclear or anterior polar cataracts were analyzed quantitatively for alpha-crystallin proteins and mRNAs using Western blot and RT-PCR analysis., respectively. The degree of modification of alpha-crystallins was determined by 2-dimensional gel electrophoresis followed by Western blotting. Higher molecular weight protein bands that were immunoreactive to anti-alphaA- and anti-alphaB-crystallin antibodies around 45 kDa accumulated more in the anterior polar cataract samples than in those with the nuclear type of cataracts. Also monomeric alphaB-crystallins accumulated more in lens epithelial cells of patients with anterior polar cataracts. By comparison, no significant changes were found in the levels of the mRNAs encoding alphaA- and alphaB-crystallins in the different types of cataracts. Both alphaA- and alphaB-crystallin proteins seemed to undergo more extensive modification in anterior polar cataracts. Conclusion. In addition to fibrotic changes, which accompany increased levels of extracellular matrix molecules, accumulation and abnormal modification of alpha-crystallins might be implicated in the pathogenic mechanism of this type of cataract.