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.

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.

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.

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.

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°.

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.

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.

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.

Functional polymorphism in manganese superoxide dismutase and antioxidant status: their interactions on the risk of cervical intraepithelial neoplasia and cervical cancer.

OBJECTIVE: Manganese superoxide dismutase (MnSOD), the primary antioxidant enzyme in mitochondria, plays a key role in protecting cells from oxidative stress. Furthermore, the MnSOD rs4880 polymorphism is associated with enzyme activity. The authors evaluated the interaction between MnSOD genotypes and cervical carcinogenesis risk and the modulating effects of serum antioxidant nutrient status (beta-carotene, lycopene, zeaxanthin/lutein, retinol, alpha-tocopherol and gamma-tocopherol). METHODS: Cases and controls for this study were recruited between June 2006 and July 2007 (263 controls, 84 cervical intraepithelial neoplasia (CIN), 94 CIN 2/3, and 99 cases of cervical cancer). The MnSOD polymorphism at rs4880T/C was examined using SNaPshot assays. Serum antioxidant vitamin concentrations were measured by reverse-phase gradient high-pressure liquid chromatography. Odds ratios (OR) and 95% confidence intervals (95%CI) were estimated after adjusting for age, menopause, parity, oral contraceptive use, smoking and alcohol consumption. RESULTS: No association was found between the MnSOD rs4880 polymorphism and cervical cancer. However, genotypes significantly modified the risk of cervical cancer in association with the serum statuses of micronutrients (P(interaction)<0.05 for beta-carotene, lycopene, zeaxanthin/lutein, alpha-tocopherol, and gamma-tocopherol). Decreased CIN1 risk in association with the MnSOD rs4880 variant genotype was also observed particularly for subjects with higher beta-carotene and gamma-tocopherol levels. Similar results were observed for lycopene and alpha-tocopherol in relation to the risk of CIN2/3. CONCLUSION: Our findings suggest that a higher antioxidant micronutrients status may decrease the risk of CIN and cervical cancer and modify the effect of the MnSOD polymorphism on disease risk.

The fabrication of nanopatterns with Au nanoparticles-embedded micelles via nanoimprint lithography.

We fabricated nanopatterns with Au nanoparticles-embedded micelles (Au-micelles) by self-assembly of block copolymers via nanoimprint lithography. The micelle structure prepared by self-assembled block copolymers was used as a template for the synthesis of Au nanoparticles (Au NPs). Au NPs were synthesized in situ inside the micelles of polystyrene-block-poly(2-vinylpyridine) (PS- b-P2VP). Au-micelles were arranged on the trenches of the polymer template, which was imprinted by nanoimprint lithography. The fabrication of line-type and dot-type nanopatterns was carried out by the combined method. In addition, multilayer nanopatterns of the Au-micelles were also proposed.

Relationship of serum antioxidant micronutrients and sociodemographic factors to cervical neoplasia: a case-control study.

BACKGROUND: Although there have been some epidemiological studies on the effects of diet and nutritional status on cervical carcinogenesis, evidence for a protective effect of antioxidant micronutrients against cervical neoplasia is insufficient. The relationship between serum antioxidant micronutrients and sociodemographic factors and the risk of cervical neoplasia was investigated in this multi-center, case-control study. METHODS: The study population included women with histopathological diagnosis of cervical intraepithelial neoplasia (CIN) 1 (n=147), CIN 2/3 (n=177), cervical cancer (n=160), and a control group (n=378). Epidemiological data were collected and the serum concentrations of beta-carotene, lycopene, zeaxanthin plus lutein, retinol, alpha-tocopherol, and gamma-tocopherol were measured using reverse-phase, gradient high-pressure liquid chromatography. RESULTS: Cervical cancer was found to be associated with older age, increased body mass index, and lower socioeconomic status as measured by education level and income. The mean serum concentrations of beta-carotene, lycopene, zeaxanthin plus lutein, retinol, alpha-tocopherol, and gamma-tocopherol of cervical cancer patients were significantly lower than those of control subjects. Odds ratio adjusted for age, smoking status, alcohol consumption, and human papillomavirus infection status revealed a significant gradient of decreasing risk of CIN 1, CIN 2/3, and cervical cancer with increasing serum concentrations of most antioxidant micronutrients. CONCLUSIONS: The results of this study show an inverse association between serum antioxidant micronutrient concentrations and the risk of cervical neoplasia. These results suggest that antioxidant micronutrients play a role in the prevention of cervical carcinogenesis.

Preparation of ag-embedded polystyrene nanospheres and nanocapsules by miniemulsion polymerization.

An isopropyl myristate (IPM) biocompatible oil and an IPM solution of dodecanethiol-capped Ag nanoparticles (NPs, 4.5 nm) were used as hydrophobes to suppress the Ostwald ripening of monomer/hydrophobe miniemulsified droplets in a surfactant-stabilized water phase. The formation of non-IPM-encapsulated nanospheres (48 nm) and IPM-encapsulated nanocapsules (90 nm) were precisely controlled by using a water-soluble and an oil-soluble initiator, respectively, in the presence of a pure IPM as a hydrophobe in miniemulsion polymerization. Well-defined PS nanospheres, on which surfaces were coated with Ag NPs (Ag/PS nanospheres, 65 nm), and nanocapsules encapsulating both NPs and IPM liquid phase (Ag-IPM/PS nanocapsules, 115 nm) were made by replacing the hydrophobe from pure IPM with Ag/IPM solution. These nanostructures were characterized by transmission and scanning electron microscopes.

Plasma carotenoids, retinol and tocopherol levels and the risk of ovarian cancer.

OBJECTIVE: We investigated the relation between plasma carotenoids, retinol and tocopherol levels and ovarian cancer risk in Korean women. DESIGN: Hospital-based case-control study. SETTING: Six tertiary medical institutes in Korea. POPULATION: Forty-five epithelial ovarian cancers and 135 age-matched controls. METHODS: Preoperative plasma concentrations of beta-carotene, lycopene, zeaxanthin plus lutein, retinol, alpha-tocopherol, and gamma-tocopherol were measured by reverse-phase, gradient high-pressure liquid chromatography. MAIN OUTCOME MEASURES: Odds ratios (OR) and 95% confidence intervals (95%CI) were estimated by tertiles to evaluate the effect of micronutrients on endometrial cancer risk after adjustment for body mass (BMI) index, menopause, parity, oral contraceptive use, smoking status, and alcohol consumption status. RESULTS: Women in the highest tertile for beta-carotene had 0.12-times the risk of ovarian cancer of in the lowest tertile (OR 0.12; 95%CI 0.04-0.36). Women with the highest tertiles of lycopene (OR 0.09; 95%CI 0.03-0.32), zeaxanthin/lutein (OR 0.21; 95%CI 0.09-0.52), retinol (OR 0.45; 95%CI 0.21-0.98), alpha-tocopherol (OR 0.23; 95%CI 0.10-0.53) and gamma-tocopherol (OR 0.28; 95%CI 0.11-0.70) had lower risk of ovarian cancer than women in the lowest tertiles. Results were consistent across strata of socio-epidemiologic factors. CONCLUSIONS: Micronutrients, specifically ss-carotene, lycopene, zeaxanthin, lutein, retinol, alpha-tocopherol, and gamma-tocopherol, may play a role in reducing the risk of ovarian cancer.

Preoperative levels of plasma micronutrients are related to endometrial cancer risk.

OBJECTIVE: To examine the relation between the plasma concentration of antioxidant micronutrients and endometrial cancer risk in Korean women. DESIGN: Hospital-based case-control study. SETTING: Seven tertiary medical institutes in Korea. POPULATION: Incidence of 28 endometrial cancer cases were identified and 140 age-matched controls selected for the same period. METHODS: Preoperative plasma concentrations of beta-carotene, lycopene, zeaxanthin plus lutein, retinol, alpha-tocopherol, and gamma-tocopherol were measured by reverse-phase, gradient high-pressure liquid chromatography. Conditional logistic regression was used to evaluate micronutrient effect after adjustment for body mass index (BMI), menopause, parity, oral contraceptive use, smoking status, and alcohol consumption status. MAIN OUTCOME MEASURES: Effect of micronutrients on endometrial cancer risk. RESULTS: The mean concentration of plasma beta-carotene (p=0.001), lycopene (p=0.008), zeaxanthin plus lutein (p=0.031), retinol (p=0.048), and gamma-tocopherol (p=0.046) were significantly lower in endometrial cancer patients than in controls. Plasma levels of beta-carotene (p for trend=0.0007) and lycopene (p for trend=0.007) were inversely associated with endometrial cancer risk across tertiles. Women in the highest tertile of plasma beta-carotene and lycopene had a 0.12-fold (95% confidence intervals (CIs) 0.03-0.48) and 0.15-fold (95% CIs 0.04-0.61) decreased risk of endometrial cancer compared to women in the lowest tertile, respectively. Other micronutrients such as zeaxanthin plus lutein (p for trend=0.142), retinol (p for trend=0.108), alpha-tocopherol (p for trend=0.322), and gamma-tocopherol (p for trend=0.087) showed no association with endometrial cancer risk. CONCLUSIONS: Plasma levels of beta-carotene and lycopene are inversely associated with the risk of endometrial cancer in Korean women.

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.

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.