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STUDY OBJECTIVES: Although the airway mucosal system plays a pivotal role in the pathogenesis of obstructive sleep apnea (OSA), the underlying disease mechanism remains unclear. The microbiome greatly impacts human health and disease, particularly in the mucosa, where it can have direct interactions. In this study, we aimed to analyze the microbiome composition in the upper airway mucosa of individuals with and without OSA to identify potential disease severity–related microbial signatures. METHODS: This population-based cohort study involved 92 participants (mean age = 62.7 ± 5.8 years; male-to-female ratio = 0.74) who underwent a physical examination and sleep study. Upper airway swab samples were collected from the nasopharyngeal mucosa to evaluate the microbiome based on 16S rRNA gene pyrosequencing. The relationship between microbiome composition and sleep parameters was explored through bioinformatics analysis. RESULTS: The average apnea-hypopnea index was 7.75 ± 6.5 events/h. Proteobacteria, Firmicutes, and Actinobacteria were the predominant phyla in the nasopharyngeal microbiota in all participants. Simpson diversity indexes were higher in patients with OSA (0.6435 ± 0.2827) than in the control patients (0.6095 ± 0.2683); however, the difference was not significant (P = .1155). Specific anaerobes negatively correlated with the lowest oxygen saturation level during sleep (sum of powered score (1) = –117.47; P = .0052). CONCLUSIONS: The upper airway microbiome of older patients with mild-moderate OSA exhibited minor differences in composition compared with that of individuals without OSA, possibly owing to environmental changes in the upper airway mucosa resulting from recurrent airway obstruction and intermittent hypoxia in patients with OSA. CITATION: Hong S-N, Kim KJ, Baek M-G, et al. Association of obstructive sleep apnea severity with the composition of the upper airway microbiome. J Clin Sleep Med. 2022;18(2):505–515.

Background While studies report a lower incidence of skin cancer in white patients with vitiligo compared with controls, the skin cancer incidence in Asian patients with vitiligo is unknown. Objectives To quantify the incidence of melanoma and nonmelanoma skin cancer (NMSC) in Korean patients with vitiligo and compare it with matched nonvitiligo controls. Methods A retrospective matched cohort study was performed with 131 245 incident vitiligo cases and 2 624 900 age- and sex-matched (1 : 20) controls at index date, who were selected from the Korean National Health Insurance database between January 2005 and December 2017. Stratified Cox proportional hazards regression (stratified by sex, birth year and index year) was used to calculate the hazard ratio (HR) of skin cancer in patients with vitiligo. Results Patients with vitiligo were followed up for a mean duration of 6·34 years compared with a follow-up period of 6·27 years for matched controls. Ultraviolet (UV) treatment-adjusted HR for melanoma in patients with vitiligo was 3·32 [95% confidence interval (CI) 2·29-4·81] and 1·29 (95% CI 1·06-1·56) for NMSC. The HRs for melanoma and NMSC in the vitiligo population without a history of UV treatment were 3·37 (95% CI 2·32-4·90) and 1·35 (95% CI 1·11-1·64), respectively. Conclusions In contrast to white patients with vitiligo, the risk of skin cancer was increased in the Korean vitiligo population. However, it is noteworthy that the skin cancer incidence in Korean patients with vitiligo was lower than that of their white counterparts. Owing to possible ethnic differences in the susceptibility to skin cancer, skin cancer surveillance in the vitiligo population may be adjusted for race. What's already known about this topic? Prior studies have reported a lower incidence of melanoma and nonmelanoma skin cancer (NMSC) in white patients with vitiligo compared with nonvitiligo controls. The skin cancer incidence in Asian patients with vitiligo is unknown. What does this study add? In contrast to white patients, the risk of both melanoma and NMSC was increased in Korean patients with vitiligo compared with controls. Owing to possible ethnic differences in susceptibility to skin cancer, skin cancer surveillance in the vitiligo population should be adjusted for race.

Motivation Ecological patterns of the human microbiota exhibit high inter-subject variation, with few operational taxonomic units (OTUs) shared across individuals. To overcome these issues, non-parametric approaches, such as the Mann–Whitney U-test and Wilcoxon rank-sum test, have often been used to identify OTUs associated with host diseases. However, these approaches only use the ranks of observed relative abundances, leading to information loss, and are associated with high false-negative rates. In this study, we propose a phylogenetic tree-based microbiome association test (TMAT) to analyze the associations between microbiome OTU abundances and disease phenotypes. Phylogenetic trees illustrate patterns of similarity among different OTUs, and TMAT provides an efficient method for utilizing such information for association analyses. The proposed TMAT provides test statistics for each node, which are combined to identify mutations associated with host diseases. Results Power estimates of TMAT were compared with existing methods using extensive simulations based on real absolute abundances. Simulation studies showed that TMAT preserves the nominal type-1 error rate, and estimates of its statistical power generally outperformed existing methods in the considered scenarios. Furthermore, TMAT can be used to detect phylogenetic mutations associated with host diseases, providing more in-depth insight into bacterial pathology. Availability and implementation The 16S rRNA amplicon sequencing metagenomics datasets for colorectal carcinoma and myalgic encephalomyelitis/chronic fatigue syndrome are available from the European Nucleotide Archive (ENA) database under project accession number PRJEB6070 and PRJEB13092, respectively. TMAT was implemented in the R package. Detailed information is available at http://healthstat.snu.ac.kr/software/tmat. Supplementary information Supplementary data are available at Bioinformatics online.

Epidemiological studies on inflammatory myopathies (IMs) show widely variable results, and studies on Asians are lacking. Despite emerging interest in the cardiovascular disease (CVD) risk associated with IMs, the prevalence of CVD in IM patients and its impact on mortality remain unclear. We conducted a nationwide, population-based study on the incidence, mortality, and associated major CVD events of IMs in the Republic of Korea over 11 years. Using the nationwide, population-based National Health Insurance claims database and the Rare Intractable Disease registration programme, we estimated incidence, mortality, and CVD occurrence. Survival was examined using the Kaplan–Meier method. Mortality rate in IMs with CVD was analysed by Cox proportional hazards regression. There were 3014 incident cases, 640 of whom died during the study period. The mean annual incidence was 7.16/106. Dermatomyositis (DM) and polymyositis (PM) had 5 year survival rates of 76.8% and 79.3%, respectively. Cardiovascular events occurred in 155 patients and 40.6% of IM patients with CVD died. Acute myocardial infarction in men had the highest risk of any CVD event in both DM [standardized incidence ratio (SIR) 4.2, 95% confidence interval (95% CI) 2.4–7.2] and PM (SIR 3.5, 95% CI 1.8–7.0). Haemorrhagic stroke had the highest hazard ratio (HR) in both DM (HR 2.31, 95% CI 1.13–4.70) and PM patients (HR 2.10, 95% CI 1.03–4.27) compared with the general population with CVD. We found persistently low incidence, poor survival, and high major CVD incidence in IMs, and increased mortality in IMs with CVD.

The performance deterioration of RO membrane processes caused by the accumulation of rejected solutes on membrane surface is an inevitable phenomenon in membrane processes. The feed spacer in spiral wound reverse osmosis (RO) membrane modules can provide the structural support to keep feed channel open and also allow turbulent flow to mitigate solute concentration build-up at the vicinity of membrane surface. The objective of this study was to investigate the effect of feed spacer thickness on both membrane fouling behavior and cleaning efficiency in a pilot test during a 659 h operation. Furthermore, fouling load distribution was studied by measuring normalized differential pressure of individual elements in pressure vessels. Foulant analysis according to feed spacer thickness was also conducted to compare fouling propensities. This study showed that a thicker feed spacer could reduce membrane fouling and subsequently decrease membrane cleaning frequency and allow an even fouling load distribution along the modules installed in a pressure vessel.

In this paper is given to implements the Android-based integration platform to provide convenience for gender development and scalability , easy access for the user. Sensor-based smart home-related products have a different way of the data exchange so platform can be integrated easily and connect heterogeneous network products and external data transmission security processing for data communication and supported to enable the integration

The effect of different compositions (in weight percent) of ethylene carbonate (EC) and propylene carbonate (PC) containing iodide/triiodide redox electrolyte on the photoelectrochemical performance of N719-sensitized nanocrystalline TiO2 solar cell was studied. The cells consisted of 0.6 M 1-hexyl-2,3-dimethylimidazolium iodide, 0.1 M LiI, 0.05 M I2 and 0.5 M 4-tert-butylpyridine in different compositions such as 1:1, 1:2, and 2:1 wt% of EC and PC. In 1:1 wt% of EC and PC containing redox electrolyte, short circuit photocurrent density (J sc) increased and open circuit voltage (V oc) decreased. But in 1:2 and 2:1 wt% of EC and PC containing redox electrolytes, V oc increased and J sc decreased but fill factor remained relatively constant. Dye-sensitized solar cells (DSSCs) prepared using these electrolytes give a short circuit photocurrent densities of 16.86, 12.71, and 12.09 mA/cm2; an open circuit voltages of 0.73, 0.78, and 0.79 V; fill factors of 0.63, 0.64, and 0.64; and an overall conversion efficiencies of 7.76, 6.34, and 6.13 % at an incident light of 100 mWcm−2 for 1:1, 2:1, and 1:2 wt% of EC/PC containing redox electrolytes, respectively. The incident photon-to-current conversion efficiency was higher in the case of 1:1 wt% of EC and PC containing redox electrolyte than 1:2 and 2:1 wt% of EC and PC containing redox electrolyte. It revealed that 1:1 wt% of EC and PC containing iodide/triiodide redox electrolyte is an effective electrolyte system for the fabrication of long-term stable DSSC.

The effects of the Pt catalyst sputter deposited on the patterned ITO glass (SD-Pt/pITO) on the photovoltaic properties and charge-transfer characteristics at the Pt/electrolyte interface of dye-sensitized solar cells (DSSCs) are studied and compared with those of a conventional Pt counter electrode deposited by thermal reduction on fluorine-doped tin oxide (FTO) glass (TD-Pt/FTO). The DSSC with the SD-Pt/pITO (sample cell) shows a lower charge-transfer resistance than that of the DSSC with the TD-Pt/FTO (reference cell), which leads to an improvement of its fill factor by about 7.6%. The long-term durability test performed for 1000 h at room temperature reveals that the sample cell retains up to 99% of its energy conversion efficiency, while that of the reference cell is degraded by about 7.2%.

The inverse-micellar preparation of Si nanoparticles (Nps) was improved by utilizing sodium naphthalide. The Si Nps were subsequently functionalized with 4-vinylbenzoic acid for their attachment onto TiO(2) films of dye-sensitized solar cells (DSSCs). The average diameter of the COOH-functionalized Si (Si-COOH) Nps was 4.6(±1.7) nm. Depth profiling by secondary-ion mass spectrometry revealed that the Si Nps were uniformly attached onto the TiO(2) films. The number of Ru(II) dye molecules adsorbed onto a TiO(2) film that was treated with the Si-COOH Nps was 42 % higher than that on the untreated TiO(2) film. As a result, DSSCs that incorporated the Si-COOH Nps exhibited higher short-circuit photocurrent density and an overall energy-conversion efficiency than the untreated DSSCs by 22 % and 27 %, respectively. This enhanced performance, mostly owing to the intramolecular charge-transfer to TiO(2) from the dye molecules that were anchored to the Si-COOH Nps, was confirmed by comparing the performance with two different Ru(II) -bipyridine dyes (N719 and N749).

This study examined the suitability of characteristics of potential strains of probiotic bacteria. Among 25 lactic acid bacteria isolated from Korean traditional fermented food, the Hard ClamMeretrix meretrix Shikhae, the SH-10 strain, which exhibited superior resistance to low pH and bile salts, was selected as a potential probiotic bacteria. By examin-ing carbohydrate utilization, morphological properties, and the 16S rRNA gene sequence, the SH-10 strain was identi-fied as Pediococcus pentosaceus (hereafter, P. pentosaceus SH-10). P. pentosaceus SH-10 was resistant to amikacin, cefotetan, ciprofloxacin, gentamicin, kanamycin, nalidixic acid, streptomycin, and vancomycin. Tests of antimicrobial activities against pathogens such as Bacillus cereus, Listeria monocytogenes, Salmonella choleraesuis, and Staphylo-coccus aureus, indicated that P. pentosaceus SH-10 inhibited the growth of pathogenic bacteria. These results suggest that P. pentosaceus SH-10 can be developed as a probiotic bacteria.Key words: Probiotics, Acid and bile tolerances, Hard Clam Shikhae, Pediococcus pentosaceus SH-10

Within the field of archeology, textile research is of growing interest because of its potential to provide relevant information regarding either the development or the technological advancement of ancient populations or the socio-economic and religious purposes of textile production. It is of paramount importance in cultural heritage research to use non-destructive techniques. Therefore, dye analyses were performed using two non-destructive methods: time-of-flight secondary ion mass spectrometry (TOF-SIMS) and Fourier transform infrared spectroscopy (FT-IR). In order to build a database, standard samples of dyed silk were prepared using several natural dye compounds; these samples were then analyzed with FT-IR and TOF-SIMS. Afterwards, spectroscopic analyses were carried out on five textile fragments coming from the 16th to the 18th century Korean tombs. FT-IR and TOF-SIMS spectra allowed the identification of fiber of the archeological textiles, making it possible to distinguish between the cotton and silk fibers. Furthermore, it was possible to identify indigo in three blue fabrics and to show its presence in a green textile. The results suggest that FT-IR and TOF-SIMS are two efficient and very helpful techniques for the characterization of excavated fabrics. Copyright © 2011 John Wiley & Sons, Ltd.

The fabrication process of semiconductor is more and more difficult as scaling down. Especially, the via profile formation is one of the main challenges which is suffering from making stable device process because ArF photo resist (PR) itself can not provide proper etch selectivity to sub-layers. Recently, many researches have been studied for the via process in terms of photo property, etch property and process compatibility using bi-layer resist process (BLR), tri-layer resist process (TLR), and multi-layer resist (MLR) process. In this paper, we proposed and demonstrated for beyond 90nm scaled logic via process consisting of high-k inter metal dielectric (IMD) using multi-layer resist (MLR) organic hard mask. Based on the test results described in this paper, the results show the higher etching selectivity to each layer and also helped to easily control the anisotropic profiles.

We studied the durability of the previously reported low mass loaded, highly efficient electrospray deposited Pt film as a cathode and Ni mesh as anode electrode in PV assisted water electrolysis system for 1000 h. This assembly showed no detectable decline in performance for initial 200 h, but thereafter it started to decline with time and showed 18% decline after 1000 h. For conclusion, we analyzed the electrode surfaces by different analyzing techniques. Results showed that Pt film was detaching from the surface and there was a deposition of passive layer of Fe2O3 on edge side of cathode surface. The iron derivative might be come from the corrosion of the stainless steel connectors that we used in PV assisted water electrolysis system. The etching and oxidation of anode surface was also observed but it might not be responsible for deterioration of performance.

Pyridinium iodide salts, which are competitive to the conventional imidazolium iodide salts, have been used for dye-sensitized solar cells as iodide sources and ionic conductivities. Pyridinium iodide series are easy to prepare and less expensive than the imidazolium series salts. In this research, quite comparable efficiencies were obtained from electrolytes with pyridinium iodide salts. For the experiments, pyridinium salts with a few different alkyl chains are applied. When a pyridinium head is modified to picolinium, which has a methyl group on the pyridinium head, a noticeable V(oc) drop has been observed. However, the length of the alkyl chains on the pyridinium head does not affect V(oc) effectively. The odd-numbered alkyl chains showed slightly lower V(oc) compared to that of the even-numbered alkyl chains. Finally, the performances of the cells with pyridinium salts are compared to those of the conventional cells with imidazolium salts.

Fluorine-containing hydrophobic thin films have been treated in this study with a mixture of fluorocarbon precursors like C2F6, C3F8, and c-C4F8 and the unsaturated hydrocarbons of C2H2 using inductively coupled plasma (ICP) and pulsed plasma (PP) deposition. Process parameters for plasma polymerization such as gas ratio, gas pressure, plasma power, pulse frequency, and processing time were investigated. Surface analytical instruments such as time-of-flight secondary ion mass spectrometry (TOF-SIMS) and x-ray photoelectron spectroscopy (XPS) were used to provide useful information about the surface composition and the chemical structure of the fluorocarbon films. Film thickness and surface morphology were also observed by using FE-SEM and AFM. Water contact angle measurements and FE-SEM results show that the ICP technique provides coarser grained films and more hydrophobic surfaces as well as a higher deposition rate compared to the PP technique. TOF-SIMS and XPS analyses indicate that the ICP technique produced more fluorine-containing functional groups, including CF2 and CF3, than the PP technique. From the curve-fitted XPS results, it is clear that fluorocarbon films grown using the ICP technique exhibited less cross-linking and higher CF2 concentrations than those grown using the PP technique.

A gel electrolyte based on polyurethane as a polymer matrix was prepared by the UV curing of a liquid electrolyte containing an aliphatic urethane acrylate. By controlling the concentration of the polymer matrix, the ionic conductivities of the gel electrolytes were varied from 9.8 × 10−3 S/cm to 4.7 × 10−3 S/cm at room temperature. The quasi-solid state dye-sensitized solar cell (DSSC) fabricated with the gel electrolyte rendered an overall energy conversion efficiency of 6.1% under irradiation of 100 mW/cm2 at room temperature. The DSSC employing the gel electrolyte showed better photovoltaic performance than the DSSC assembled without the polyurethane at temperatures above 55 °C.

The effect of the addition of single and binary additives to a mixed solvent, ethylene carbonate + γ-butyrolactone, on the performance of dye-sensitized TiO 2 solar cells (DSSCs) has been investigated. The addition of a single additive, 2-(dimethylamino)-pyridine, to the electrolyte containing an ionic salt, 1,2-dimethyl-3-propylimidazolium iodide, in the mixed solvent results in an enhancement of the cell performance. The performance of the cell has been further enhanced by the addition of the second additive, 5-chloro-1-ethyl-2-methylimidazole. The resulting DSSC has performed better than the one based on the conventional electrolyte in acetonitrile. The dependence of the stability of the cells on the temperature has been evaluated over the range of 30–120 °C for outdoor applications.

A novel alkylimidazolium iodide containing an amide group, 1-(2-hexanamidoethyl)-3-methylimidazol-3-ium iodide (amido-ImI), was synthesized to act as the quasi-solid-state electrolyte of dye-sensitized solar cells (DSSCs). The DSSC with the amido-ImI electrolyte exhibited short-circuit photocurrent density ( J sc ) and overall energy conversion efficiency ( η ) that were improved by 7.2% and 10.2%, respectively, compared to those obtained with the cell containing 1-hexyl-2,3-dimethylimidazolium iodide, a commonly used liquid electrolyte, at 100 mW cm −2 . Furthermore, the stability of the DSSC was enhanced by the presence of amido-ImI.

The morphology from symmetric diblock copolymers of poly(styrene-b-propylmethacrylate) (PS-PPrMA), where polystyrene (PS) block was perdeuterated near the copolymer/air and copolymer/substrate interfaces and in the bulk, was characterized by using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Elemental depth profiles measured in the negative ion mode by a Cs + primary ion beam demonstrate variations in hydrogen, deuterium, carbon, oxygen and hydrocarbons within the diblock copolymer according to the depth. The annealed deuterated poly(styrene-b-propy[methacrylate) (dPS-PPrMA) copolymer samples showed a decrease in the deuterated PS secondary ion peak intensity as compared to the as-cast samples. TOF-SIMS depth profiling was obtained for the lamellar morphology of dPS-PPrMA which is found to orient parallel to the surface of the substrate. This preferential orientation resulted in a periodic variation in the composition of each block that continued through the entire copolymer film with thickness of 700 and 2100A. Temperature-dependent annealing studies on dPS-PPrMA thin film on the silicon substrates were performed to investigate the lower critical ordering transition (LCOT) properties of diblock copolymers.

The initial decrease in the short-circuit photocurrent density (Jsc) of a Ru(II)–bipyridine dye-sensitized solar cell (DSSC) during illumination is correlated with the decrease in the amount of remaining dye adsorbed on the TiO2 film monitored by UV–vis absorption spectroscopy. The analyses reveal that the illumination causes the N719 dye molecules to desorb from the TiO2 film into the electrolytic solution. The amount of dye remaining adsorbed on the TiO2 film is influenced by the viscosity and donor number of the electrolytic solution. More dye molecules remain adsorbed on the TiO2 film in the solution of 3-methoxypropionitrile than in the less viscous solution of acetonitrile. The addition of water and Triton X-100 to the 3-methoxypropionitrile solution results in the enhancement of the dye desorption, partly due to the increase in the donor number.

A surface-induced orientation of symmetric, deuterated polystyrene/poly(propyl methacrylate) diblock copolymers, dPS-PPrMA with different molecular weights (Mn = 135 000, 119 600, and 75 300) was investigated using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Elemental depth profiles obtained in the negative ion mode by a Cs+ primary ion beam demonstrate variations in hydrogen, deuterium, carbon, oxygen, and hydrocarbons within the diblock copolymer according to the depth. Solution casting films of the copolymers with thicknesses of 700 and 2100 A exhibited no preferential orientation of the microdomain morphology with respect to the surface at room temperature. Annealing the copolymer films at 215 °C for 4 h produced a dramatic orientation of the microdomains parallel to the surface of the film. This preferential alignment provided regular oscillation in the composition of both blocks, which continued through the entire film. The periodicity as determined from a depth profile of TOF-SIMS showed good agreement with the results of small-angle X-ray scattering. Positive and negative ion molecular depth profiles by a C60+ cluster ion beam also provide information pertaining to the lower disorder–order transition (LDOT) behavior of the dPS-PPrMA copolymer. Depth profile results indicate a PPrMA layer preferentially located at the copolymer/silicon substrate interface. The microdomain separation processes of dPS-PPrMA were investigated as a function of the annealing temperature and time. Copyright © 2010 John Wiley & Sons, Ltd.

Nylon 6 fibers are used, for the first time, in dye-sensitized solar cells (DSSCs). The overall energy conversion efficiency obtained with 0.18 M nylon 6 reaches 6.2%, which is comparable to that (6.7%) obtained without adding nylon 6 on the day of cell fabrication. However, it is found that the long-term stability of the DSSCs with nylon 6 is superior to that of a reference electrolyte as a result of the complexation of nylon 6 with I(3)(-). Furthermore, nylon 6 is found to be a corrosion inhibitor for silver metal in the electrolyte containing I(3)(-).

Blocking layers are formed on the conductive fluorine-doped tin oxide (FTO) substrate by using titanium (IV) bis(ethylacetoacetato) diisopropoxide precursor solutions with different concentration to investigate the effect of the precursor concentration on thickness and morphology of blocking layers and photovoltaic property in dye-sensitized solar cell. Increase in the precursor concentration from 0.05 M to 1.2 M leads to increase in the blocking layer thickness from 10 nm to 240 nm. Besides increase in the thickness, nanoparticulate intralayer morphology is developed as increasing the precursor concentration. Photovoltaic property, especially photocurrent density (JSC), is influenced by the precursor concentration, where JSC increases with increasing the concentration, reaches maximum at around 0.1 M (blocking layer thickness is about 20 nm), decreases gradually up to 0.4 M and become close to the value without blocking layer for further increase in the concentration. Photovoltages increase slightly after formation of blocking layer, but not significantly altered compared with the extent of photocurrent change. It has been found that the precursor concentration with around 0.1 M provides the optimum condition to protect the loss of electrons within our experimental condition and at this condition the photoconversion efficiency is able to be enhanced by about 6% compared with that without blocking layer. Electrochemical impedance spectroscopic study shows that the dependence of photovoltaic property on Ti precursor concentration is closely related to the charge transfer resistance at the blocking layer/electrolyte interface, where the electron loss at near FTO substrate is effectively protected by the blocking layer with the maximum charge transfer resistance.

A highly viscous liquid electrolyte is prepared by adding a small amount of amylopectin into dimethylsulfoxide solvent. By using this viscous electrolyte, a dye-sensitized solar cell (DSSC) enhances the short-circuit photocurrent density and solar-to-electricity conversion efficiency by 22% and 8.4%, respectively, compared to those obtained with the reference cell without amylopectin. Furthermore, the stability of the DSSC is enormously improved by the addition of amylopectin. Polarization curves indicate that amylopectin is a reasonable corrosion inhibitor for silver metal in the electrolyte containing I 3 − /I − couple.

A urease-positive bacterium isolated from sea water was identified as Photobacterium sp. by morphological, biochemical, and 16s rRNA gene analyses and named Photobacterium sp. strain HA-2. 2.0-fold increase enzyme activity was observed in LB medium containing 3% NaCl and 0.1% urea or not and the enzyme activity was 16.0-fold lower compared to urease-positive Vibrio parahaemolyticus AQ4673 strain when grown in the LB medium containing 3% NaCl with 0.1% urea. The cloning and sequencing of Photobacterium sp. strain HA-2 urease gene cluster is currently being analyzed in our laboratory.

Dye-sensitized solar cells (DSSCs) treated with COOH-functionalized Si (Si-COOH) nanoparticles exhibited a higher short-circuit photocurrent density (Jsc) and open-circuit voltage than the corresponding untreated DSSC. The enhanced Jsc is attributed to the sensitization resulting indirectly from the N719 dye attached to the Si-COOH nanoparticles by intramolecular charge transfer and directly from the Si nanoparticles anchored onto the TiO2 film. As a result of the improved performance, the overall energy conversion efficiency was increased by 17%, as compared to that for a reference cell without the Si-COOH nanoparticles at 100 mW cm−2.

The performance of a Ru(II) dye-sensitized nanocrystalline TiO 2 solar cell (DSSC) with both Triton X-100 and water as additives in 3-methoxypropionitrile solutions is described. In the presence of these additives, the open-circuit voltage ( V oc ), fill factor and stability of the cell increased, while the short-circuit photocurrent density decreased compared to those found in their absence. Based on these changes, the DSSC yielded a higher solar-to-electricity conversion efficiency of 5.9%, compared to 5.3% for the cells fabricated without the additives. Furthermore, the addition of Triton X-100 to the water-added electrolyte was found to render the Ag metal corrosion resistant.

Different fluorocarbon thin films were deposited on Si substrates using a plasma-polymerization method. Fluorine-containing hydrophobic thin films were obtained by inductively coupled plasma (ICP) and pulsed plasma (PP) with a mixture of fluorocarbon precursors C2F6, C3F8, and c-C4F8 and the unsaturated hydrocarbons of C2H2. The influence on the fluorocarbon surfaces of the process parameters for plasma polymerization, including the gas ratio and the plasma power, were investigated under two plasma-polymerized techniques with different fluorocarbon gas precursors. The hydrophobic properties, surface morphologies, and chemical compositions were elucidated using water contact angle measurements, field emission-scanning electron microscope, x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and time-of-flight secondary ion mass spectrometry (TOF-SIMS). In this study, the ICP technique provides coarser grained films and more hydrophobic surfaces as well as a higher deposi...

A novel ionic electrolyte, 3-(iodohexyl)-1-(3-(triethoxysilyl)propylcarbamoyl)-1H-benzo[d]imidazol-3-ium iodide (SSBI) was prepared through the reaction of N-[3-(triethoxy-4-silyl)propyl]-1H-benzimidazole-1-carboxamide with 1,6-diiodohexane for the quasi-solidification of the electrolytic solution of a dye-sensitized solar cell (DSSC). The SSB-containing electrolyte, the sol electrolyte, in a DSSC was converted to a gel by heating it at 60 °C for 30 min in an oven. The DSSC consisting of the gel electrolyte showed a solar-to-electricity conversion efficiency comparable to that of the cell with the reference liquid electrolyte, and consistently higher stability than that of the reference cell. The performances of the DSSCs containing the reference, sol and gel electrolytes were discussed by scanning electron microscopy (SEM), impedance and chronoamperometric measurements, ionic conductivity, and UV–vis absorption spectroscopy.

Plasma-polymerized fluorine-containing thin films were fabricated by five different plasma methods, viz. inductively coupled plasma (ICP), pulsed-plasma (PP), capacitively coupled plasma (CCP), self-ignition plasma (SIP), and plasma source ion implantation/inductively coupled plasma (PSII/ICP). Octafluoropropane (C3F8) was mixed with acetylene (C2H2) to investigate the effect of different plasma techniques on the films. The properties of the plasma polymers, viz. hydrophobic properties, binding structure, deposition rate, and chemical composition, varied considerably depending on the plasma polymerization method. The plasma-polymerized thin films made by the different methods were characterized using surface analytical instruments: field-emission scanning electron microscope (FE-SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS), and time-of-flight secondary ion mass spectrometry (TOF-SIMS). Cross-section images from FE-SEM revealed that the deposition rate of the polymer film in the case of using CCP plasma was higher while that for PSII/ICP and self-ignition plasma, respectively, was lower compared with the deposition rate of the ICP and pulsed-plasma. The water contact angle measurement showed that the ICP and PSII/ICP techniques produced more hydrophobic surfaces. XPS and TOF-SIMS analyses indicated that the ICP and PSII/ICP methods produced more F-containing functional groups, especially CF2 and CF3 groups. Also, the NEXAFS results revealed that the ICP and PSII/ICP techniques provide more fluorine species on the plasma polymer surface compared with other techniques.

The identification of the colorants used on ancient textiles provides a historical pathway to the understanding of the processes associated with one of the oldest of chemical technologies, namely textile dyeing. In this paper, time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to detect dyes on textiles avoiding the time-consuming and destructive extraction procedures necessary for the spectrophotometric and chromatographic methods previously used. The plant dyes investigated belong to a variety of chemical groups, which include curcumin, crocin, carthamin, purpurin, alizarin, brazilin, shikonin, and indigo. Reference textile samples were prepared with dye extracts of plants and were characterized by TOF-SIMS. TOF-SIMS spectra for the dyed textiles showed element ions from metallic mordants, specific fragment ions, and molecular ions from organic dyes. Remnant dyes on excavated textiles have also been identified using TOF-SIMS. The ancient textile sample showed the presence of indigo clearly, although the fiber itself had degraded badly. From the results, it was concluded that most of plant dyes can be identified with TOF-SIMS and it is a very promising technique for the archaeology field.

Spherical rutile TiO 2 particles (14–20 nm) and their corresponding well-defined round clusters (500–600 nm) were obtained by using a cationic surfactant cetyltrimethylammonium bromide (CTAB). The surfactant was employed in two stages, i.e., in the hydrolysis of TiCl 4 and then in the precipitation of the corresponding Ti(IV) polymers at approximately 46 °C. On the other hand, without CTAB in the hydrolyzing solution, irregular clusters consisting of typical ellipsoidal TiO 2 particles were produced. The advantage of such spherical rutile TiO 2 particles and clusters was examined in terms of photovoltaic characteristics of a dye-sensitized solar cell (DSSC). Significantly higher overall solar energy conversion efficiency was obtained for a DSSC using the film of these spherical rutile TiO 2 particles, compared with that of a cell using a TiO 2 film of ellipsoidal particles. A mechanism for the formation of these spherical rutile particles and clusters is proposed.

Imidazolium iodides (Im+I−s) were synthesized with different substituents of the cation and used as electrolytes in dye-sensitized solar cells (DSSCs), and the effects of such substituents were investigated in terms of the photovoltaic performance of the cells. Synthesized iodides were verified by 1H-NMR. Among the iodides, 1,3-diethylimidazolium iodide enabled a solar energy conversion efficiency of 4.8% for its DSSC, while 1-(4-acetophenyl)-3-ethylimidazolium iodide rendered an efficiency of 3.1% for its cell. In all cases the short-circuit photocurrent (J sc) was found to increase with decrease in size of the substituent, which was also verified to be valid in the case of a quasi-solid state DSSC. Results are explained by the electrostatic interactions between solvated Im+ and negatively charged species based on the correlation between diffusion coefficients of I− and I 3 − and J sc values. These explanations are supported by steady-state voltammetry and electrochemical impedance spectroscopy (EIS).

Platycosides extracted from Platycodi Radix were analyzed by HPLC coupled with electrospray ionization multistage tandem mass spectrometry (HPLC/ESI-MS(n)). Predominant [M+Na](+) ions in positive mode and [M-H](-) ions in negative mode in the direct ESI-MS spectra of extract provided information on molecular weights, but minor components and isomers could not be discriminated. However, combining HPLC and ESI-MS(n), allowed eleven platycosides, including four acetylated platycodin isomers and two prosapogenines to be analyzed. During MS(2) analysis conducted to elucidate the structures of platycosides, fragment ions provided information on sugar moieties attached at C-28 of triterpene structure of the platycosides. Glycosidic bond cleavages at C-3 were revealed by fragment ions in MS(3) spectra. Some characteristic fragment ions not related to sugar bond cleavage revealed that an esterified triterpene is linked to sugars at C-28. The only sugar ring-cross cleavage corresponding to 90 Da in the negative MS(2) spectrum took place at an arabinosyl sugar moiety. By using HPLC/ESI-MS(n), three acetylated platycosides in Platycodi Radix extract were newly identified.

A counter electrode was prepared for a dye-sensitized solar cell (DSSC) through electrochemical deposition of mesoporous platinum on fluorine-doped tin oxide glass in the presence of a structure-directing nonionic surfactant, octaethylene glycol monohexadecyl ether (C 16 EO 8 ). The DSSC fabricated with the electrochemically deposited Pt (ED-Pt) counter electrode rendered a higher solar-to-electricity conversion efficiency of 7.6%, compared with approximately 6.4% of the cells fabricated with the sputter-deposited or most commonly-employed thermal deposited Pt counter electrodes. This enhanced efficiency is attributed to the higher short-circuit photocurrent arising from the increases in the active surface area and light reflection as well as the decrease in the sheet resistance of the ED-Pt film, relative to those of the Pt films prepared by the other two deposition methods. The sputter-deposited Pt film yielded almost the same photovoltaic characteristics as the thermal deposited Pt film. The Pt films were characterized by FE-SEM, AFM, cyclic voltammetry, chronoamperometry, electrochemical impedance spectroscopy, sheet resistance measurements, adhesion tests, and light reflection tests.

The effects of low-temperature O2 plasma treatment of a TiO2 film are studied with the objective of improving the performance of dye-sensitized solar cells (DSSCs). X-ray photoelectron spectra (XPS) reveal that the ratio of titanium dioxide to titanium sub-oxides is increased in the O2 plasma-treated TiO2 film, compared with that of the untreated TiO2 film. This increase suggests that the oxygen vacancies in the film are effectively reduced. The near-edge X-ray absorption fine structure (NEXAFS) spectra results agree with the XPS result. It is proposed that there is a correlation between the shifts of the peaks in the NEXAFS spectra and the adsorption of N719 dye on the TiO2 particles. A DSSC having an O2 plasma-treated, 4 μm thick TiO2 film electrode renders a short-circuit photocurrent of 7.59 mA cm−2, compared with 6.53 mA cm−2 for a reference cell with an untreated TiO2 electrode of the same thickness. As a result of these changes, the solar-to-electricity conversion efficiency of the O2 plasma-treated cell is found to be 4.0% as compared with 3.5% for the untreated cell. This improvement in the performance is rationalized on the basis of increased N719 dye adsorption on to the TiO2, due to the reduction in the number of oxygen vacancies caused by the oxygen plasma treatment.

Network hybrid gel prepared with tetraethyl orthosilicate, 3-aminopropyltrimethoxysilane (APS) and poly(ethylene glycol) was used as an electrolyte matrix in a quasi-solid state dye-sensitized solar cell (DSSC). Change in pH of this hybrid gel by varying the composition of APS was found to have remarkable effects on the photoelectrochemical performance of the cell. The hybrid gel matrix, having silane polymer backbones with free amine functionality, was characterized by FT-IR spectra and FE-SEM images, and the assembled DSSC by photocurrent-voltage and incident photon to current conversion efficiency curves. The unsealed, quasi-solid state DSSC with the hybrid gel has shown an increase in the open-circuit voltage ( V oc ) and a steady decrease in the short-circuit photocurrent ( J sc ), with increase in the content of APS. A maximum conversion efficiency of 4.5% was obtained for a DSSC by using 20% of APS in its hybrid gel at a light intensity of 100 mW cm −2 . Upon replacing the amino group of APS by bulkier aniline and benzophenoaniline groups, conversion efficiencies of the corresponding DSSCs were reduced. Variations in the V oc and J sc are explained in terms of shift of the flat band potential of TiO 2 and a complex formation between I 3 − and −NH 2 of APS of the electrolyte.

Summary A synthetic route was developed to link N3 dye to polyacrylic acid (PAA) using ethylenediamine (en) as the linker. The resulting complex, PAA–en–N3, was then coated onto a TiO2 film. The modified TiO2 film electrode (hereafter PAA–en–N3/TiO2), when used as the photoanode in a dye-sensitized solar cell (DSSC), exhibited enhanced solar energy conversion efficiency compared with that of the usual DSSC with the N3/TiO2 film electrode. The increase in efficiency was attributed to the increased open-circuit voltage (Voc) and short-circuit photocurrent (Jsc). The increase in Voc was attributed to the formation of a hydrophobic PAA–en–N3 layer on the TiO2/electrolyte interface, while the increase in Jsc was attributed to the additional dye acquired by the TiO2 film from the PAA–en–N3 complex.

The microscale pyrolysis of a mixture of 2,4,6-tribromophenol (2,4,6-TBP) and 2,4,6-trichlorophenol (2,4,6-TCP) was investigated. Several pyrolyzed products resulting from the gas phase reactions were analyzed by gas chromatography/mass spectrometry (GC/MS). Some products, including tetrabromo- and tetrachloro-dibenzo- p -dioxins, were identified by comparison of their retention times and mass spectra with those of products obtained from the pyrolysis of the corresponding 2,4,6-TBP and 2,4,6-TCP. 1,3,6,8- and 1,3,7,9-halogen substituted dioxin isomers were produced as major products via the condensation of phenoxyphenol radicals. The condensation of 2,4,6-TBP led to the more rapid production of tetrabromodibenzo- p -dioxins (TBDDs) than of tetrachlorodibenzo- p -dioxins (TCDDs) from 2,3,6-TCP due to the weaker C–Br than C–Cl bond strength. In the study of a mixture of 2,4,6-TCP and 2,4,6-TBP, the most abundant congeners were dibromo-dichlorodibenzo- p -dioxins. On the basis of the pyro-products analysis, the thermal decay of 2,4,6-TCP and 2,4,6-TBP, and the formation of halogenated dioxins as a function of the pyrolysis temperature were also investigated. The increased reactivity can be explained by the hypothesis that “dibromophenoxy radical are formed more easily by debromination of 2,4,6-TBP than that of 2,4,6-TCP, which rapidly reacts with 2,4,6-TCP and 2,4,6-TBP at low temperatures”. The formation distribution of tetra-bromochlorodibenzo- p -dioxins (tetra-BCDDs) indicated that more chlorinated dioxins were produced at low temperatures, but more brominated dioxins were formed at high temperatures.

Titanium dioxide (TiO2) film for dye-sensitized solar cells (DSSCs) has surface defects such as oxygen vacancies created during the annealing process. The authors used a plasma treatment technique to reduce defects on TiO2 surfaces. They investigated the influence of different gas plasma treatments of TiO2 film on the photoelectric performance of DSSC. Short-circuit photocurrent density (Jsc), open-circuit photovoltage (Voc), and the amount of adsorbed dye for DSSCs were measured. As a result, the solar-to-electricity conversion efficiencies of the O2- and N2-treated cells increased by 15%–20% compared to untreated cells. On the other hand, solar energy conversion efficiency of CF4-plasma treated cells decreased drastically. The increased amount of adsorbed dye on the TiO2 film was measured by time-of-flight secondary ion mass spectrometry. TiO2 surfaces modified by plasma treatment were characterized using analytical instruments such as x-ray photoelectron spectroscopy and near-edge x-ray absorption fine...

In a novel approach, fullerene, C 60 was attached to N3 dye ( cis -bis(4,4′-dicarboxy-2,2′-bipyridine)dithiocyanato ruthenium(II)) via diaminohydrocarbon linkers (L) with different carbon chain lengths. The resulting complexes (each designated as N3-L-C 60 ) were characterized by FT-IR spectra, FE-SEM images, and EDX analysis. The short-circuit photocurrent density ( J sc ) of the dye-sensitized solar cells (DSSCs) using the fullerene-attached sensitizers varied markedly depending on the chain length of the linker. In the case of the linker 1,6-diaminohexane, the J sc , V oc and conversion efficiency of the pertaining cell were found to be 11.75 mA/cm 2 , 0.70 V and 4.5%, respectively, as against the values of 10.55 mA/cm 2 , 0.68 V and 4.0%, respectively, for a DSSC with ordinary N3 dye. The J sc variations are discussed on the basis of effective dye adsorptions on TiO 2 films. The possible favorable effects for V oc enhancement, caused by hydrophobic atmosphere around the TiO 2 particles due to diaminohydrocarbon chains and by the negative shift of the flat band potential of TiO 2 by NH groups, are offset by the mediation of back electron transfer by C 60 ; this phenomenon is seen as the reason for minimal V oc changes.

This study examined the thermal reactions of 2,4-dibromophenol (diBP), 2,6-diBP and 2,4,6-triBP. The products obtained under pyrolytic conditions were analyzed by gas chromatography/mass spectrometry (GC/ MS). 2,7-dibromodibenzo-p-dioxin (diBDD) was the major compound produced from the thermal reaction of 2,4-diBP. In addition, monoBDD and triBDDs were obtained through a process of debromination and bromination, respectively. The pyrolysis of 2,6-diBP and 2,4,6-triBP produced two major brominated dioxin isomers through direct condensation and a Smiles rearrangement. The two ortho-Brs in 2,6-diBP and 2,4,6triBP mainly led to the production of dioxins, whereas in addition to 2,7-diBDD, 2,4-diBP produced two furans as minor products, 2,8-dibromodibenzofuran (diBDF) and 2,4,8-triBDF, through the intermediate dihydroxybiphenyl (DOHB). The maximum yield of the major dioxins was obtained at 400 o C, and decomposition by debromination at 500 o C resulted in less substituted bromodioxins.

A ZnO-covered TiO2 (denoted as ZnO/TiO2) film was prepared by incorporating a small quantity of particulate ZnO in a TiO2 matrix by thermal chemical vapor deposition. When used in a dye-sensitized solar cell, an enhancement was observed in both short-circuit photocurrent (Jsc) and open-circuit voltage (Voc) by 12% and 17%, respectively, relative to those of a cell containing a bare TiO2 film. The observed Jsc enhancement is attributed to the increase in the surface area of the ZnO/TiO2 film, and the Voc enhancement to the formation of a potential barrier by ZnO at TiO2/electrolyte interface. The films were characterized by FE-SEM, EDX, and XRD.

Five new monoacylglycerols (MAGs) were isolated from the marine sponge Stelletta sp. by reversed-phase high-performance liquid chromatography and analyzed by positive ion fast atom bombardment mass spectrometry (FAB-MS). FAB mass spectra of these compounds produced abundant sodium-adducted molecules [M+Na]+ from a mixture of 3-nitrobenzyl alcohol and sodium iodide. The structural elucidation of these sponge MAGs was carried out by FAB tandem mass spectrometry (MS/MS). To find diagnostic ions for the characterization of the MAGs, authentic MAGs were initially analyzed by collision-induced dissociation (CID) MS/MS. The CID MS/MS of [M+Na]+ precursor ions resulted in the formation of numerous characteristic product ions via a series of dissociative processes. The product ions formed by charge-remote fragmentation (CRF) provided important information for the characterization of acyl chains substituted at the glycerol backbone, and product ions at m/z 84, 97, 113 and 139 were diagnostic for the sodiated glycerol backbone. On the basis of these fragmentation patterns, the structures of five MAGs extracted from marine sponge were elucidated. In addition, high-resolution mass measurement was performed to obtain the elemental compositions of the MAGs. Copyright © 2007 John Wiley & Sons, Ltd.