ToF-SIMS and AFM Characterization of Brown Cosmetic Contact Lenses: From Structural Analysis to the Identification of Pigments.

Over the years, soft contact lenses for vision correction and cosmetic and therapeutic purposes have been greatly improved. For cosmetic contact lenses, the pigments need to be nontoxic, and the position of the pigment layer is particularly important because of the risks posed by pigment elution and the roughness of the lens surface. In this paper, we characterized the properties of brown cosmetic contact lenses made by three different manufacturers using surface analytical techniques. The surface topographies of the noncolored and colored parts were obtained by atomic force microscopy (AFM), and the position and composition of the pigment layer were determined by analyzing the cross section of the contact lenses using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). The influence of pigment location on surface roughness was also examined. In addition, to find the method of the evaluation for the risk of surface elution of the pigments in the colored parts, the mass spectra and ion images of the surfaces were obtained by time-of-flight secondary ion mass spectrometry (ToF-SIMS) with a new sample preparation. From the ToF-SIMS spectra, we observed specific fragment ions of the poly(hydroxyethyl methacrylate) (PHEMA) polymer and found differences in the composition of the pigment layer depending on the manufacturers. The cross-sectioned image and 3D chemical characterizations of metallic and specific ions in the brown cosmetic contact lenses clearly indicated the spatial distribution and location of the pigment layer that can be used for the evaluation of pigment elution.

Quantitative Analysis and Band Gap Determination for CIGS Absorber Layers Using Surface Techniques.

Recently, Cu(In X Ga(1-X))Se2 (CIGS) absorber layers have been extensively studied by many research groups for thin-film solar cell technology. CIGS material is particularly promising due to its exceptionally high absorption coefficient and large band gap range, which is adjustable as a function of alloy stoichiometry. To enhance the conversion performance of CIGS solar cells, understanding the CIGS structure and composition is a crucial challenge. We conducted a quantitative study to determine the bulk composition of the major elements such as Cu, In, Ga, and Se of four different CIGS photovoltaic cells. The compositional information was obtained by X-ray fluorescence (XRF), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and femtosecond laser ablation inductively coupled plasma mass spectrometry (fs-LA-ICP-MS). Then, the XRF concentration ratio was compared with the intensity ratio of fs-LA-ICP-MS to investigate the potential of accurate and rapid analysis using the fs-LA-ICP-MS technique. In contrast to the bulk information, the surface techniques can supply detailed information about the chemical composition across the depth profile. Here, elemental depth distributions of CIGS thin films were investigated using magnetic sector secondary ion mass spectrometry (SIMS) and Auger electron spectroscopy (AES). The atomic distributions of four different CIGS absorber layers exhibited a good agreement although they were obtained using two different surface instruments, AES and SIMS. Comparative analysis results of different CIGS absorber layers using SIMS, AES, and fs-LA-ICP-MS provide us with the appropriate technique for the information of accurate composition in a rapid analysis time. Thanks to a simple approach using the Ga/(In + Ga) ratio, the optical band gap energy of the Cu(In X Ga(1-X))Se2 quaternary layer was monitored in the entire CIGS layer. The elemental distribution and the band gap determination were then used to elucidate their relationship to the corresponding CIGS cell efficiency result.

The effect of continuity of care on the incidence of end-stage renal disease in patients with newly detected type 2 diabetic nephropathy: a retrospective cohort study.

BACKGROUND: Diabetic nephropathy requires periodic monitoring, dietary modification, and early intervention to prevent the disease severity within limited resource settings. To emphasize the importance of continuous care for chronic diseases, various studies have focused on the association between continuity of care (COC) and common adverse outcomes. However, studies aimed at understanding the effect of COC on the incidence of chronic diseases, such as end-stage renal disease (ESRD), are few. The aim of this study was to determine whether there is an association between COC and the incidence of ESRD among patients with diabetic nephropathy. Moreover, we identified individual- and hospital-level factors associated with the incidence of ESRD among diabetic nephropathy patients. METHODS: We conducted a retrospective cohort study using the administrative National Health Insurance claims data from 2005 to 2012 in the Republic of Korea. The dependent variable, a binary variable, was the incidence of ESRD due to diabetic renal complication. In addition, using the COC index as a binary variable with a cutoff point of 0.75, we divided patients into a 'Good COC group' (COC index≥0.75) and a 'Bad COC group' (COC index< 0.75). The survival analysis was performed using the Cox proportional hazards models. RESULTS: Among 3565 diabetic renal complication patients, ESRD occurred among 83 diabetes mellitus patients (2.3%). Nephropathy patients with lower COC level (< 0.75) had 1.99 times higher risk of ESRD incidence (95% confidence interval [CI]:1.27-3.12). In addition, the lowest income level patients had higher hazard ratio (HR) of ESRD than the highest income level patients (HR: 1.69 95% CI: 0.95-2.98), while patients with disabilities had 2.70 higher HR of ESRD than patients without disabilities (95% CI: 0.64-43). CONCLUSIONS: Among patients with diabetic renal complication, higher continuity of care was associated with lower risk of ESRD. It is therefore recommended that continuous follow-up be encouraged to prevent ESRD among diabetic renal complication patients. Moreover, disparities in health outcomes between socially vulnerable groups including patients with disabilities and those in the lowest income level should be addressed.

Complementary Characterization of Cu(In,Ga)Se2 Thin-Film Photovoltaic Cells Using Secondary Ion Mass Spectrometry, Auger Electron Spectroscopy, and Atom Probe Tomography.

To enhance the conversion performance of solar cells, a quantitative and depth-resolved elemental analysis of photovoltaic thin films is required. In this study, we determined the average concentration of the major elements (Cu, In, Ga, and Se) in fabricated Cu(In,Ga)Se2 (CIGS) thin films, using inductively coupled plasma atomic emission spectroscopy, X-ray fluorescence, and wavelengthdispersive electron probe microanalysis. Depth profiling results for CIGS thin films with different cell efficiencies were obtained using secondary ion mass spectrometry and Auger electron spectroscopy to compare the atomic concentrations. Atom probe tomography, a characterization technique with sub-nanometer resolution, was used to obtain three-dimensional elemental mapping and the compositional distribution at the grain boundaries (GBs). GBs are identified by Na increment accompanied by Cu depletion and In enrichment. Segregation of Na atoms along the GB had a beneficial effect on cell performance. Comparative analyses of different CIGS absorber layers using various analytical techniques provide us with understanding of the compositional distributions and structures of high efficiency CIGS thin films in solar cells.

Fluorescent sensing of triphosphate nucleotides via anthracene derivatives.

A nucleotide is composed of a nucleobase, a five-carbon sugar, and phosphate groups. Recognition of these three sites can provide useful information for the development of selective fluorescent receptors for a specific nucleotide. In this paper, anthracene derivatives with two imidazolium groups at the 1,8- and 9,10-positions, quaternary ammonium groups, or the boronic acid group were examined for the recognition of nucleotides, such as ATP, GTP, CTP, TTP, UTP, ADP, and AMP, via fluorescence changes. The anthracene group provides the interaction between the bases of the nucleotides. The imidazolium and quaternary ammonium groups induce hydrogen bonding interactions with the phosphate groups of the nucleotides. The boronic acid group can interact with the ribose of the nucleotides.

Effects of solid-state fermented rice on lipid metabolism and antioxidant status in high-cholesterol-fed rats.

We investigated the effect of solid-state fermented rice cultured with Basidiomycota (sangwhang) and Monascus ruber on lipid metabolism and antioxidant activity. Forty 4-week-old male Sprague-Dawley rats were fed high cholesterol diets in which carbohydrate sources in the treatment groups consisted of non-fermented rice and sangwhang or M. ruber rice at 80% and 20%, respectively, for 5 weeks. Supplementation with sangwhang and M. ruber rice had no effect on growth and food intakes in high-cholesterol-fed rats. The plasma triglyceride concentration was not significantly different among the groups. Supplementation with M. ruber rice resulted in lower plasma and hepatic cholesterol concentrations and atherogenic index compared to the control group, while the plasma high-density lipoprotein-cholesterol concentration was elevated. In addition, fermented rice cultured with M. ruber-supplemented animals had greater bile acid excretion. The M. ruber groups had significantly lower plasma and hepatic levels of thiobarbituric acid-reactive substances than the control group. Moreover, hepatic antioxidant enzyme activities, including catalase and superoxide dismutase, were significantly higher in the M. ruber group. In conclusion, fermented rice, especially M. ruber rice, was very effective for improving the lipid metabolism and reducing oxidative stress by up-regulating the hepatic antioxidant enzymes in high-cholesterol-fed rats.

Highly effective fluorescent and colorimetric sensors for pyrophosphate over H2PO4- in 100% aqueous solution.

[Structure: see text]. This study demonstrated that Zinpyr-1*Zn2+ acts as a fluorescent and colorimetric sensor for pyrophosphate at pH 7.4. In addition, Zinpyr-1*Cu2+ and DIARB-1*Cu2+ complexes were found to act as selective fluorescent sensors for pyrophosphate. Furthermore, the chemosensors Zinpyr-1*Zn2+ and Zinpyr-1*Cu2+ show highly selective and ratiometric fluorescence changes for pyrophosphate compared with H2PO4-.

A highly selective fluorescent chemosensor for Pb2+.

A new fluorescent sensor based on rhodamine B for Pb2+ was synthesized. The new fluorescent sensor showed an extreme selectivity for Pb2+ over other metal ions examined in acetonitrile. Upon the addition of Pb2+, an overall emission change of 100-fold was observed, and the selectivity was calculated to be 200 times that of Zn2+. The signal transduction occurs via of reversible CHEF (chelation-enhanced fluorescence) with this inherent quenching metal ion.

Unique hydrogen bonds between 9-anthracenyl hydrogen and anions.

Unique hydrogen bonds of the 9-H of anthracene moieties in hosts 1 and 2 with fluoride and pyrophosphate ions were observed on the basis of the (1)H NMR experiments. Furthermore, hosts 1 and 2 act as a colorimetric sensor and a fluorescent chemosensor for the recognition of fluoride ion, respectively.