Preventing condensation of objective lens in noncontact wide-angle viewing systems during vitrectomy.

AIM: To assess the optimal conditions for preventing condensation of objective lens during vitrectomy with noncontact wide-angle viewing systems (WAVSs). METHODS: We explored the effectiveness of the coating with ophthalmic viscoelastic device (OVDs) on the corneal surface and the soaking the objective lens in warm-saline for preventing condensation of objective lens. First, to find the optimal soaking time to keep the objective lens warm, we measured the temperature of objective lens every minute after soaking in warm saline. Second, to find optimal distance between cornea and objective lens, which provide as wide a view as possible and less condensation at the same time, we measured the condensation time with different distances. With the obtained optimal soaking time and distance, we explored the effect of coating cornea with OVDs and soaking objective lens in warm saline on condensation time. RESULTS: One and 5min of soaking in warm saline was most effective for keeping the lens warm enough (45.1°C±2.1°C for 1min and 46.4°C ±1.0°C for 5min, P=0.109). The mean condensation times for the control group at 1, 3, and 5 mm from corneal surface to objective lens were 1±0.4, 4±1.4, 190±26.1s, respectively, thus 5 mm was most optimal distance for vitrectomy with WAVSs. For the OVD coating group, the mean condensation times were 1.5±0.3, 13±1.4, and 200±23.9s at 1, 3, and 5 mm distance and borderline significant compared with control group (P=0.068, 0.051, and 0.063, respectively). With the 1-minute warm saline soaking group, the mean condensation time were extended to 188±34.4, 416±65.7, and 600±121.3s at 1, 3, and 5 mm distance and statistically significant compared with control (P=0.043, 0.041 and 0.043, respectively). CONCLUSION: OVD coating on corneal surface shows no difference on condensation time with control group. However, soaking the objective lens in warm saline revealed statistically significant extension of condensation time compared to control group. Therefore, keeping the objective lens warm with soaking in warm saline is a simple but effective to prevent condensation of objective lens during vitrectomy. The thermodynamics between objective lens and cornea during vitrectomy warrants further investigation.

Management of Acute Submacular Hemorrhage with Intravitreal Injection of Tenecteplase, Anti-vascular Endothelial Growth Factor and Gas.

PURPOSE: To evaluate the visual and anatomical outcomes for neovascular age-related macular degeneration with submacular hemorrhage after intravitreal injections of tenecteplase (TNK), anti-vascular endothelial growth factor (VEGF) and expansile gas. METHODS: This study was a retrospective clinical case series following 25 eyes of 25 patients. All patients received a triple injection using 0.05 mL TNK (50 µg), 0.05 mL anti-VEGF and 0.3 mL of perfluoropropane gas. Retreatment with anti-VEGF was performed as needed. Preoperative and postoperative best-corrected visual acuity and central retinal thickness were analyzed. RESULTS: The mean logarithm of the minimum angle of resolution of best-corrected visual acuity improved significantly from 1.09 ± 0.77 at baseline to 0.52 ± 0.60 at 12 months (p < 0.001). The mean central retinal thickness also improved significantly from 545 ± 156 at baseline to 266 ± 107 at 12 months (p < 0.001). A visual improvement of 0.3 logarithm of the minimum angle of resolution unit or more was achieved in 15 eyes (60%). During the 12 postoperative months, an average of 4.04 intravitreal anti-VEGF injections was applied. CONCLUSIONS: A triple injection of TNK, anti-VEGF, and a gas appears to be safe and effective for the treatment of submacular hemorrhage secondary to neovascular age-related macular degeneration.

An operando surface enhanced Raman spectroscopy (SERS) study of carbon deposition on SOFC anodes.

Thermally robust and chemically inert Ag@SiO2 nanoprobes are employed to provide the surface enhanced Raman scattering (SERS) effect for an in situ/operando study of the early stage of carbon deposition on nickel-based solid oxide fuel cell (SOFC) anodes. The enhanced sensitivity to carbon enables the detection of different stages of coking, offering insights into intrinsic coking tolerance of material surfaces. Application of a thin coating of gadolinium doped ceria (GDC) enhances the resistance to coking of nickel surfaces. The electrochemically active Ni-YSZ interface appears to be more active for hydrocarbon reforming, resulting in the accumulation of different hydrocarbon molecules, which can be readily removed upon the application of an anodic current. Operando SERS is a powerful tool for the mechanistic study of coking in SOFC systems. It is also applicable to the study of other catalytic and electrochemical processes in a wide range of conditions.

CdS/C60 binary nanocomposite films prepared via phase transition of PS-b-P2VP block copolymer.

We demonstrate the well-defined control of phase transition of a polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) block copolymer from spherical micelles to lamellar structures, in which CdS and C60 nanoparticles (NPs) are selectively positioned at the P2VP domains. The CdS NPs are in situ synthesized using PS-b-P2VP block copolymer templates that are self-assembled in PS-selective solvents. The CdS-PS-b-P2VP micellar structures are transformed to lamellar phase by adjusting a solvent selectivity for both blocks. In addition, a binary system of CdS/C60 embedded in PS-b-P2VP lamellar structures (CdS/C60-PS-b-P2VP) is fabricated by embedding C60 molecules into P2VP domain though charge-transfer complexation between pyridine units of PS-b-P2VP and C60 molecules. The CdS/C60-PS-b-P2VP nanostructured films are characterized by transmission electron microscopy (TEM) and UV-Vis spectrometer.

Well-organized raspberry-like Ag@Cu bimetal nanoparticles for highly reliable and reproducible surface-enhanced Raman scattering.

Surface-enhanced Raman scattering (SERS) is ideally suited for probing and mapping surface species and incipient phases on fuel cell electrodes because of its high sensitivity and surface-selectivity, potentially offering insights into the mechanisms of chemical and energy transformation processes. In particular, bimetal nanostructures of coinage metals (Au, Ag, and Cu) have attracted much attention as SERS-active agents due to their distinctive electromagnetic field enhancements originated from surface plasmon resonance. Here we report excellent SERS-active, raspberry-like nanostructures composed of a silver (Ag) nanoparticle core decorated with smaller copper (Cu) nanoparticles, which displayed enhanced and broadened UV-Vis absorption spectra. These unique Ag@Cu raspberry nanostructures enable us to use blue, green, and red light as the excitation laser source for surface-enhanced Raman spectroscopy (SERS) with a large enhancement factor (EF). A highly reliable SERS effect was demonstrated using Rhodamine 6G (R6G) molecules and a thin film of gadolinium doped ceria.

Selective cyclooxygenase inhibitors increase paclitaxel sensitivity in taxane-resistant ovarian cancer by suppressing P-glycoprotein expression.

OBJECTIVE: The purpose of this study was to investigate whether selective cyclooxygenase (COX) inhibitors promote paclitaxel-induced apoptosis in taxane-resistant ovarian cancer cells by suppressing MDR1/P-glycoprotein (P-gp) expression. METHODS: Taxane-resistant ovarian cancer cells were cultured with paclitaxel alone or combined with a selective COX inhibitors. The expression patterns of MDR1/P-gp and the ability of COX inhibitors to inhibit growth of taxane-resistant ovarian cancer cells were measured. The efficacy of prostaglandin E2 (PGE2) supplementation was measured to evaluate the mechanisms involved in suppressing MDR1 gene expression. RESULTS: P-gp was upregulated in taxane-resistant ovarian cancer cells compared to paired paclitaxel-sensitive ovarian cancer cells. An 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that selective COX inhibitors significantly enhanced the cytotoxic effects of paclitaxel in taxane-resistant ovarian cancer cells via a prostaglandin-independent mechanism. These increased apoptotic effects were further verified by measuring an increased percentage of cells in sub-G1 stage using flow cytometry. Selective COX inhibitors suppressed MDR1 and P-gp expression. Moreover, combined treatment with paclitaxel and selective COX inhibitors increased poly (ADP-ribose) polymerase (PARP) cleavage in taxane-resistant ovarian cancer cells. CONCLUSION: Selective COX inhibitors significantly promote paclitaxel-induced cell death in taxane-resistant ovarian cancer cells in a prostaglandin-independent manner. COX inhibitors could be potent therapeutic tools to promote paclitaxel sensitization of taxane-resistant ovarian cancers by suppressing MDR1/P-gp, which is responsible for the efflux of chemotherapeutic agents.

Etched graphite with internally grown Si nanowires from pores as an anode for high density Li-ion batteries.

A novel architecture consisting of Si nanowires internally grown from porous graphite is synthesized by etching of graphite with a lamellar structure via a VLS (vapor-liquid-solid) process. This strategy gives the high electrode density of 1.5 g/cm(3), which is comparable with practical anode of the Li-ion battery. Our product demonstrates a high volumetric capacity density of 1363 mAh/cm(3) with 91% Coulombic efficiency and high rate capability of 568 mAh/cm(3) even at a 5C rate. This good electrochemical performance allows porous graphite to offer free space to accommodate the volume change of Si nanowires during cycling and the electron transport to efficiently be improved between active materials.

Multipositional silica-coated silver nanoparticles for high-performance polymer solar cells.

We demonstrate high-performance polymer solar cells using the plasmonic effect of multipositional silica-coated silver nanoparticles. The location of the nanoparticles is critical for increasing light absorption and scattering via enhanced electric field distribution. The device incorporating nanoparticles between the hole transport layer and the active layer achieves a power conversion efficiency of 8.92% with an external quantum efficiency of 81.5%. These device efficiencies are the highest values reported to date for plasmonic polymer solar cells using metal nanoparticles.

Preparation of silica nanospheres and porous polymer membranes with controlled morphologies via nanophase separation.

We successfully synthesized two different structures, silica nanospheres and porous polymer membranes, via nanophase separation, based on a sol-gel process. Silica sol, which was in situ polymerized from tetraorthosilicate, was used as a precursor. Subsequently, it was mixed with a polymer that was used as a matrix component. It was observed that nanophase separation occurred after the mixing of polymer with silica sol and subsequent evaporation of solvents, resulting in organizing various structures, from random network silica structures to silica spheres. In particular, silica nanospheres were produced by manipulating the mixing ratio of polymer to silica sol. The size of silica beads was gradually changed from micro- to nanoscale, depending on the polymer content. At the same time, porous polymer membranes were generated by removing the silica component with hydrofluoric acid. Furthermore, porous carbon membranes were produced using carbon source polymer through the carbonization process.

Helical silicon/silicon oxide core-shell anodes grown onto the surface of bulk silicon.

We demonstrate a simple route for preparing Si/SiO(x) urchin-like structures in which Si/SiO(x) core-shell nanocoils protruded out from the surface of bulk Si, via high-temperature annealing of Pt-decorated Si powders. The carbon-coated urchin-like anodes with micro- and nanostructured composite exhibit a significantly improved electrochemical performance with a high specific capacity of 1600 mAh/g and a superior cycling performance of 70 cycles at a rate of 0.2 C due to the nanocoil conformation and SiO(x) buffer layer. More importantly, the composite results in a significantly enhanced the volumetric capacity with ∼3780 mAh/cc, compared to bulk Si (∼2720 mAh/cc) after fully lithiation to 0 V.

Shape control of cadmium hydroxides (Cd(OH)2) sensitive to pH quenching depth and massive production of CdSe nanocrystals by their chemical transformation.

This study demonstrates that the structure of cadmium hydroxides (Cd(OH)(2)) precipitated from a basic cadmium nitrate solution can be finely controlled by adjusting the pH of the precursor solution. The synthesis process involves only pouring the saturated solution into pure water to quench the pH and the total process is finished within 30 s. At a shallow pH quenching, the unstable nanoparticles turned into microparticles via a ripening process. Cd(OH)(2) was precipitated in the form of one-dimensional nanowires and then two-dimensional plates as the pH quenching was increased. At a large pH quenching, porous aggregates of Cd(OH)(2) were obtained due to the too fast precipitation. The ultrafine Cd(OH)(2) nanowires were readily transformed into CdSe chain-like nanocrystals. The transformation was quick and gave 100% yield, facilitating massive production of CdSe nanocrystals in an aqueous condition. The Cd(OH)(2) nanowires were directly grown on Si nanowires and transformed into CdSe chain-like nanocrystals, decorating the surface of each Si nanowire.

Patterning of various silicon structures via polymer lithography and catalytic chemical etching.

We demonstrate a facile fabrication of a rich variety of silicon patterns with different length scales by combining polymer lithography and a metal-assisted chemical etching method. Several types of polymer patterns were fabricated on silicon substrates, and silver layers were deposited on the patterned silicon surfaces and used to etch the silicon beneath. Various silicon patterns including topographic lines, concentric rings, and square arrays were created at a micro- and nanoscale after etching the silicon and subsequent removal of the patterned polymer masks. Alternatively, the arrays of sub-30 nm silicon nanowires were produced by a chemical etching of the silicon wafer which was covered with highly ordered polystyrene-block-polyvinylpyridine (PS-b-PVP) micellar films. In addition, silicon nanohole arrays were also generated by etching with hexagonally packed silver nanoparticles that were prepared using PS-b-PVP block copolymer templates.

Ocular toxocariasis in Korea.

PURPOSE: To analyze the characteristics and clinical manifestations of clinically diagnosed and serologically confirmed ocular toxocariasis in patients. METHODS: Thirty-three eyes of 33 patients diagnosed as having ocular toxocariasis at the Hallym University Medical Center between January 1999 and December 2008 were included in the study. The diagnosis of ocular toxocariasis was based on clinical features and confirmed serologically by enzyme-linked immunosorbent assay and immunoblotting. All patients were interviewed by using a structured questionnaire that included risk factors that might account for the introduction of Toxocara larvae. Demographics, social characteristics determined from the questionnaire, and clinical features were evaluated. RESULTS: A total of 33 eyes of 33 patients were enrolled in this study: 24 (73%) patients were men, and mean patient age was 41.6 ± 11.0 years. Ten of 28 patients (36%) who responded to the questionnaire had a history of contact with pets, and 23 (82%) had a history of consuming raw food. The most common symptoms were blurred vision in 22 eyes (67%) and floaters in six eyes (18%). The toxocariasis was unilateral in all patients, and the inflammation was acute in two-thirds of the patients. In 17 eyes (52%), Toxocara granuloma was found in the peripheral retina. Nineteen eyes (58%) had visual acuity of 20/40 or better at presentation and improved significantly after treatment. Final visual acuity was 20/40 or better in 26 eyes (79%). CONCLUSIONS: Ocular toxocariasis in Korea usually affects young adults to middle-aged men. The clinical manifestation is unilateral and presents as acute inflammation with a peripheral inflammatory mass. Visual prognosis with appropriate treatment is good.

The volume of tumor mass and visual field defect in patients with pituitary macroadenoma.

PURPOSE: We used the Swedish interactive threshold algorithms (SITA) standard strategy of Humphrey perimetry, to analyze the pattern of visual field (VF) defects and evaluate the quantitative correlation between the tumor volume and severity of VF defects in patients with pituitary macroadenoma. METHODS: We reviewed 50 patients with pituitary macroadenoma who received VF test and 11 patients were excluded. VF analysis was performed with Humphrey perimeter using the SITA standard strategy. The tumor volume was assessed radiologically via brain magnetic resonance images and was calculated using Cavalieri's principle. We used the mean deviation (MD) and pattern standard deviation (PSD) of the Humphrey parameter to measure VF defect severity, and then analyzed the correlation of tumor volume with VF defects. RESULTS: Twenty nine patients (74%) showed abnormal VF and bitemporal field changes, which were the most common field defects on presentation. Seven patients (18%) had unilateral VF defects, 22 patients (56%) had bilateral VF defects. The tumor volume of the patients with VF defects was significantly larger than that of patients with normal VF (p = 0.006). The tumor volume exhibited significant negative correlation with MD (r = -0.693; p < 0.001) and significant positive correlation with PSD (r = 0.589; p < 0.001). CONCLUSIONS: In patients with pituitary macroadenoma, there was a variety of VF defects and a high correlation between the tumor volume and the severity of VF defects. SITA standard strategy can be a fast and quantitative method for evaluating central VF defects.

Extremely superhydrophobic surfaces with micro- and nanostructures fabricated by copper catalytic etching.

We demonstrate a simple method for the fabrication of rough silicon surfaces with micro- and nanostructures, which exhibited superhydrophobic behaviors. Hierarchically rough silicon surfaces were prepared by copper (Cu)-assisted chemical etching process where Cu nanoparticles having particle size of 10-30 nm were deposited on silicon surface, depending on the period of time of electroless Cu plating. Surface roughness was controlled by both the size of Cu nanoparticles and etching conditions. As-synthesized rough silicon surfaces showed water contact angles ranging from 93° to 149°. Moreover, the hierarchically rough silicon surfaces were chemically modified by spin-coating of a thin layer of Teflon precursor with low surface energy. And thus it exhibited nonsticky and enhanced hydrophobic properties with extremely high contact angle of nearly 180°.

Common polymorphisms in methylenetetrahydrofolate reductase gene are associated with risks of cervical intraepithelial neoplasia and cervical cancer in women with low serum folate and vitamin B12.

OBJECTIVE: We evaluated associations between folate, vitamin B12, and the methylenetetrahydrofolate reductase (MTHFR) gene, and risk of cervical intraepithelial neoplasia (CIN) and cervical cancer. METHODS: This multicenter case-control study enrolled 927 Korean women (440 controls, 165 patients with CIN 1, 167 patients with CIN 2/3, and 155 patients with cervical cancer, aged 20-75 years). RESULTS: Patients with cervical cancer had significantly lower median serum folate and vitamin B12 concentrations vs. controls. Higher serum folate was significantly associated with lower cervical cancer risk (p for linear trend = 0.0058) with a trend for a lower CIN risk after multivariate adjustment. Low folate and the MTHFR 677 C > T variant were associated with a higher risk for CIN2/3 and cervical cancer vs. wild-type or heterozygous genotypes with high folate [OR, 2.39 (1.18-4.85) and 3.19 (1.43-7.13)]. Low vitamin B12 and the MTHFR 677 C > T variant also were associated with a higher risk for CIN 2/3 and cervical cancers [OR, 2.52 (1.17-5.42) and 2.40 (1-5.73)] vs. wild-type or heterozygous status with high vitamin levels. CONCLUSION: Serum folate concentration is inversely associated with the risk of cervical cancer, and the MTHFR variant genotype may increase CIN and cervical cancer risk in women with low folate or vitamin B12 status.

A case of irritated seborrheic keratosis associated with a previous incision site.

An 83-year-old woman had undergone an external dacryocystorhinostomy with silicone intubation. Before the surgery, no skin lesions were observed on the incision site. Three months after surgery, the patient complained of a brown-to-black pigmented elevation at her previous skin incision site. A punch biopsy of the pigmented mass was performed. The histopathologic findings confirmed the clinical diagnosis of irritated seborrheic keratosis (SK). SK can occur several months postoperatively and can suddenly increase in size, so surgeons need to carefully check patients' skin prior to surgery. To our knowledge, this is the first reported case of irritated SK discovered on a previous skin incision site.

Intakes of vitamin A, C, and E, and beta-carotene are associated with risk of cervical cancer: a case-control study in Korea.

Cervical cancer is one of the most common gynecological malignancies in Korea, although the incidence has been declining in recent years. This study explored whether antioxidant vitamin intakes influenced the risk of cervical cancer. The association between antioxidant vitamin intakes and cervical cancer risk was calculated for 144 cervical cancer cases and 288 age-matched, hospital-based controls using unconditional logistic regression models. Cases reported statistically lower mean dietary intakes of vitamin A, beta -carotene, and vitamin C than did controls. Total intakes of vitamins A and E, which included both dietary and supplement intake, were also lower in cases. Those patients in the highest quartiles of dietary vitamin A, beta -carotene, and vitamin C intakes had statistically significantly lower cervical cancer risks than those in the lowest quartiles for vitamin A, beta -carotene, and vitamin C: odds ratio (OR) = 0.36 [95% confidence interval (CI) = 0.19-0.69), OR = 0.48 (CI = 0.26-0.88), and OR = 0.36 (CI = 0.18-0.69), respectively. Total intakes of vitamins A, C, and E were strongly inversely associated with cervical cancer risk: OR = 0.35 (CI = 0.19-0.65), OR = 0.35 (CI = 0.19-0.66), and OR = 0.53 (CI = 0.28-0.99), respectively. The findings support a role for increased antioxidant vitamin intake in decreasing the risk of cervical cancer. These associations need to be assessed in large prospective studies with long-term follow-up.

The effects of polymorphisms in methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTR), and methionine synthase reductase (MTRR) on the risk of cervical intraepithelial neoplasia and cervical cancer in Korean women.

The purpose of the study was to investigate the association between cervical cancer risk and single-nucleotide polymorphisms (SNPs) in three one-carbon metabolism genes, methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTR), and methionine synthase reductase (MTRR) in Korean women. Twelve SNPs were identified in MTHFR, MTR, and MTRR in the 927 case-control samples, which included 165 cervical intraepithelial neoplasia 1 (CIN1), 167 cervical intraepithelial neoplasia 2 and 3 (CIN2/3), 155 cervical cancer patients, and 440 normal controls. The frequencies of the genotypes and haplotypes were assessed in the controls, CINs, and cervical cancers. Individual carriers of the variant allele C of MTHFR A1298C (rs1801131) had a 0.64-fold [95% confidence interval (CI): 0.42-0.98] decreased risk for CIN2/3 compared with common homozygotes. However, no significant association was found between most other variants and cervical cancer risk. The results also identified an increased CIN1 risk in carriers with at least one copy of haplotype 3 in the MTHFR gene (odds ratio, 1.88; 95% CI: 1.03-3.42). In conclusion, there was no significant association between most SNPs in MTHFR, MTR, or MTRR and the risk of CIN and cervical cancer in Korean women. In addition, there was no significant association of MTHFR haplotypes with risk of CIN2/3 and cervical cancer.