Efficiencies of Dye-Sensitized Solar Cells with Hollow SnO2 Nanofiber/TiO2 Nanoparticle Composite Photoanodes

In this study, we present dye-sensitized solar cells (DSSCs) with improved efficiencies by using SnO2/TiO2 composite photoanodes containing SnO2 at various concentrations. The composites consisted of hollow nanofibers (h-NFs) of SnO2 and TiO2 nanoparticles (NPs). The combination of the large surface area of the NPs and the efficient charge transport in the h-NFs make the use of the SnO2/TiO2 composites advantageous. DSSCs in which composite photoanodes with 50 wt% h-NFs were incorporated showed enhanced efficiencies that were 20% higher than the efficiencies of cells containing TiO2 NP-based photoanodes. These results indicated the improved electron diffusion length and shorter electron transfer time in the composite structures due to the crosslinking between h-NFs and NPs.

Analysis of oxygen vacancy in Co-doped ZnO using the electron density distribution obtained using MEM

Oxygen vacancy (VO) strongly affects the properties of oxides. In this study, we used X-ray diffraction (XRD) to study changes in the VO concentration as a function of the Co-doping level of ZnO. Rietveld refinement yielded a different result from that determined via X-ray photoelectron spectroscopy (XPS), but additional maximum entropy method (MEM) analysis led it to compensate for the difference. VO tended to gradually decrease with increased Co doping, and ferromagnetic behavior was not observed regardless of the Co-doping concentration. MEM analysis demonstrated that reliable information related to the defects in the ZnO-based system can be obtained using X-ray diffraction alone.

Study on the formation of magnetic nanoclusters and change in spin ordering in Co-doped ZnO using magnetic susceptibility

The temperature-dependent magnetic susceptibility measurement could provide a useful methodological approach as well as experimental clues for identifying the origin of magnetism in magnetic semiconductor.

p-type conductivity generated by ferromagnetic ordering via percolative anionic H chain formation in ZnCoO

We report on the simultaneous realization of p-type conductivity and strong ferromagnetism in heavily Co-doped ZnO thin films in the presence of a high concentration of hydrogen impurities. Through ab initio calculations, we find that the microscopic origin of hole carrier generations and ferromagnetic ordering is due to the partially occupied band of the percolative structures wherein the carrier-induced magnetic interactions can stabilize the strong spin-parallel state.

Fabrication of ZnCoO nanowires and characterization of their magnetic properties

Hydrogen-treated ZnCoO shows magnetic behavior, which is related to the formation of Co-H-Co complexes. However, it is not well known how the complexes are connected to each other and with what directional behavior they are ordered. In this point of view, ZnCoO nanowire is an ideal system for the study of the magnetic anisotropy. ZnCoO nanowire was fabricated by trioctylamine solution method under different ambient gases. We found that the oxidation of trioctylamine plays an essential role on the synthesis of high-quality ZnCoO nanowires. The hydrogen injection to ZnCoO nanowires induced ferromagnetism with larger magnetization than ZnCoO powders, while becoming paramagnetic after vacuum heat treatment. Strong ferromagnetism of nanowires can be explained by the percolation of Co-H-Co complexes along the c-axis.

Distant metastatic lesions in patients with differentiated thyroid carcinoma. Clinical implications of radioiodine and FDG uptake

AIM

Many investigators have reported an inverse relationship between iodine and glucose utilization of differentiated thyroid carcinoma (DTC) according to its degree of differentiation; however, not every DTC is compatible with this phenomenon. This study was conducted to evaluate the clinical implication of iodine and glucose uptake at distant metastatic lesions in DTC patients.

PATIENTS, METHODS

64 DTC patients (women 47; mean age 49.9 ± 16.4 years) with distant metastasis who underwent post (131)I treatment whole-body scan (RxWBS) and FDG PET/CT were included in the study. Radioiodine (RAI) and FDG uptake of metastatic lesions were evaluated. TSH stimulated serum thyroglobulin (s-Tg) were obtained.

RESULTS

53 of 64 patients (82.8%) were RAI(+) group, and 37 patients (57.8%) were FDG(+) group. Patients in the RAI(-) group showed a higher rate of FDG uptake than RAI(+) group (100.0% vs. 49.1%, p = 0.002). Patients in the FDG(-) group showed a higher rate of RAI uptake than FDG(+) group (100.0% vs. 70.3%, p = 0.002). Patients with s-Tg < 100 ng/ml were frequently observed in the FDG(-)/RAI(+) group and the FDG(+)/RAI(-) group (p = 0.023). And patients with s-Tg ≥ 500 ng/ml were more frequently observed in the FDG(+)/RAI(+) group, compared with the FDG(+)/RAI(-) group (p = 0.036). Reduced disease-specific survival (DSS) was observed in patients with RAI(-) (p = 0.003), FDG(+) (p = 0.006), SUVmax > 3.6 (p<0.001), and s-Tg > 75.8 ng/ml (p = 0.009). In multivariate analysis, only a SUVmax > 3.6 was significantly predictive of DSS (p = 0.006).

CONCLUSION

An inverse relationship between RAI and FDG uptake, flip-flop phenomenon, was observed in patients with metastatic lesions of DTC. Reduced disease-specific survival was observed in patients with FDG(+), RAI(-) in metastatic lesions, or high s-Tg value.

Successful melting and density measurements of Cu and Ag single crystals with an electrostatic levitation (ESL) system

By using grain-free single crystal specimens, the melting of Cu and Ag using electrostatic levitation (ESL) and obtaining their high-temperature densities were accomplished for the first time.

Plasma treatment effect on dye-sensitized solar cell efficiency of hydrothermal-processed TiO2 nanorods

Atmospheric plasma (AP) treatment was carried out on TiO2 nanorods (NRs) that were hydrothermally grown on F-doped SnO2 (FTO)/glass. The effects of AP treatment on the surface of the TiO2 NRs were investigated, where the treatment involved the use of the reactive gases H2, N2, and O2. The surface energy of AP-treated TiO2 NRs was about 1.5 times higher than that of untreated TiO2 NRs (364.3 mJ/m2). After AP treatment, the increase of the peak area ratios of the Ti2O3 and TiO2 peaks in the XPS spectra resulted in a decrease in the number of oxygen vacancies in the TiO2 NRs. The efficiency of a dye-sensitized solar cell (DSSC) based on the N2-plasma-treated TiO2 NRs, which was approximately 1.11%, was about 79% higher than that of a DSSC based on the untreated TiO2 NRs.

The influence of hospital volume and surgical treatment delay on long-term survival after cancer surgery

BACKGROUND

We conducted a population-based retrospective cohort study to investigate the influence of hospital volume, delay of surgery, and both together on the long-term survival of postoperative cancer patients.

METHODS

Using information from the Korea Central Cancer Registry from 2001 through 2005 and the National Health Insurance claim database, we determined survival for 147 682 patients who underwent definitive surgery for any of six cancers.

RESULTS

Regardless of cancer site, surgical patients in low- to medium-volume hospitals showed significantly worse survival [adjusted hazard ratio (aHR) = 1.36-1.86] than those in high-volume hospitals in multivariable analyses. Among the latter, treatment delays > 1 month were not associated with worse survival for stomach, colon, pancreatic, or lung cancer but were for rectal [aHR = 1.28; 95% confidence interval (CI), 1.17-1.40] and breast (aHR = 1.59; 95% CI, 1.37-1.84) cancer. For patients in low- to medium-volume hospitals, treatment delay was associated with worse survival for all types of cancer (aHR = 1.78-3.81).

CONCLUSION

Our findings suggest that the effect of hospital volume and surgical treatment delay on overall survival of cancer patients should be considered in formulating or revising national health policy.

Improving the precision of Hall effect measurements using a single-crystal copper probe

The circuitry and components of a Hall measurement kit were replaced with single-crystal copper (SCC) wires and parts prepared by a novel wire fabrication process. This process preserved the grain-free structure of SCC grown by the Czochralski method. The new kit was used to determine, with greatly improved precision, the electrical coefficients such as carrier density and mobility, establish the reproducibility of the measured values, and define the semiconductor type. The observed reduction in electrical signal losses and distortion has been attributed to grain boundary elimination.

Effects of TiO2 nanorod length and post-annealing on the electrical properties of TiO2 nanobarbed fiber structures

TiO2 nanobarbed fiber (NBF) structures consisting of TiO2 nanorods (NRs) on TiO2 nanofibers (NFs) were fabricated. The mean length and diameter of the TiO2 NRs grown for 6 h was 1.38 microm and 71 nm, respectively. One NR was connected to other NRs and the junction points between the TiO2 NRs increased with increasing TiO2 NR length. The crystal structure of the TiO2 NFs and NRs was rutile and anatase, respectively. After post-annealing, only the intensity of the TiO2 NBF peaks increased without any significant structural changes. Raman spectroscopy showed that the TiO2 NBF structure consisted of anatase (TiO2 NFs) and rutile (TiO2 NRs). The bandgap of the TiO2 NBF structure prepared during a TiO2 NR growth time from 0 to 6 h decreased from 3.23 eV to 3.10 eV. The conductivity of the TiO2 NBFs with longer NRs was enhanced by post-annealing.

Improved cell viability of biocompatible nutrient-contained polymeric nanofibers

Nanofibers containing cell nutrients (PGDs) were fabricated by mixing 5 wt% poly(epsilon-caprolactone) (P), 4 wt% gelatin (G), and 0-2.4 wt% Dulbecco's Modified Eagle's Medium (D). The contact angles showed a considerable decrease from 118.4 degrees on the P scaffold to 17.6 degrees on PGD1.6 (containing 1.6 wt% D). The weight loss ratios between PGD1.6 and the P nanofiber, and between PGD1.6 and the PG nanofiber by degradation after 28 days were approximately 3.1 and 1.4, respectively. The rate of cell proliferation on PGD1.6 was greater than that on the PG nanofiber by 14% and 38% for the exchanged and unexchanged culture media, respectively. The physicochemical measurement results showed that the PGDs exhibited enhanced hydrophilic properties and rapid biodegradation. The PGD nanofibers with increasing D content showed better conditions for long-term cell viability. The growth mechanism of the cells on the PGDs was explained by an attachment and growth process.

Variations in the course of the cervical vagus nerve on thyroid ultrasonography

BACKGROUND AND PURPOSE

Only 1 ultrasonography study that described the variation of the VN had been published at the time our research was begun. The purpose of this study was to evaluate the incidence and type of variation in the course of the cervical VN on thyroid ultrasonography.

MATERIALS AND METHODS

From August 2009 to September 2010, 163 consecutive patients were evaluated by sonography for the screening and characterization of thyroid nodules (mean age, 49.0 ± 14.4 years, male:female, 20:143). Two types of variation were defined as follows: 1) anterior variation, when the course of the VNs changed from the typical location to an anterior location in front of the CCA; and 2) medial variation, when the course of the VNs changed from the typical location to a location medial to the CCA (between CCA and thyroid gland). The incidence of the each variation was studied.

RESULTS

Variation in the course of the VN occurred in 5.5% (18/326) of cases. The anterior variation was observed in 4.3% (14/326, right:left = 4:10), and the medial variation was observed in 1.2% (4/326, right:left = 3:1). For both variations, the VN was close to or nearly abutted the thyroid gland after it changed course.

CONCLUSIONS

Variation in the course of the cervical VN could be assessed by ultrasonography. Two variations were observed in 5.5% of cases. The anterior variation was more common than the medial variation.

Risk factors for device-associated infection related to organisational characteristics of intensive care units: findings from the Korean Nosocomial Infections Surveillance System

Device-associated infections (DAIs) have been the major causes of morbidity and mortality of patients in intensive care units (ICUs). This study evaluated the risk factors for DAIs in ICUs. Ninety-six medical or surgical ICUs of 56 hospitals participated in the Korean Nosocomial Infections Surveillance System between July 2007 and June 2008. The occurrence of catheter-associated urinary tract infection (CAUTI), central line-associated bloodstream infection (CABSI), and ventilator-associated pneumonia (VAP) were monitored and DAI rates were calculated. Data associated with ICU characteristics were collected and Poisson regression was used for statistical analysis. Rates of CAUTI, CABSI, and VAP were 3.87 per 1000 urinary catheter days, 2.23 per 1000 central line days, and 1.89 per 1000 mechanical ventilator days, respectively. Rates of CAUTI were higher in ICUs in Seoul (P=0.032) and ICUs of major teaching hospitals (P=0.010). The ICUs of university-affiliated hospitals showed lower CAUTI rates (P=0.013). CABSI rates were higher in Seoul (P=0.001) and in medical ICUs (P=0.026). VAP rates were lower in ICUs of hospitals with more than 900 beds compared with hospitals with 400-699 beds (P=0.026). VAP rates were higher in surgical ICUs (P<0.0001) and increased 1.13-fold with each 100-unit increase in beds per infection control professional (P=0.003). The organisational and institutional characteristics of ICUs may influence DAI rates and there is a need for improvement in the incidence of VAP, CAUTI or CABSI.

Surface modification of and selective protein attachment to a flexible microarray pattern using atmospheric plasma with a reactive gas

The hydrophobic and hydrophilic properties of the surface of poly-ether sulfone (PES) films were controlled by an atmospheric pressure plasma (AP) treatment using reactive gases (Ar/H(2) and Ar/O(2)). The surface properties of the Ar/H(2) and Ar/O(2) in series AP-treated PES films showed higher surface roughness (approximately 120%), surface energy (approximately 30%) and hydrophilic properties (oxygen content approximately 10%) than the Ar/O(2) AP-treated PES film. The protein staining results confirmed that an activated region on the patterned PES film with high selectivity and sensitivity was well-defined and formed. This method is suitable for fabricating flexible protein adhesive chips with uniform biomolecular adhesive properties.

Synchronous gastric cancer in primary sporadic colorectal cancer patients in Korea

BACKGROUND AND AIMS

Colorectal cancer has been reported to be the malignancy most frequently associated with gastric cancer in Korea. The aim of this study was to define the frequency and clinical characteristics of synchronous gastric cancer detected at preoperative esophagogastroduodenoscopy (EGD) in colorectal cancer patients.

MATERIALS AND METHODS

This prospective study analyzed the EGD results from 1,542 consecutive colorectal cancer patients who underwent surgery from January 2003 to December 2005 at the Center for Colorectal Cancer, National Cancer Center, Korea.

RESULTS

Of the 1,542 cases, 1,155 (74.9%) underwent EGD at our center and 387 underwent EGD at other hospitals within 6 months before surgery. Of the 1,542 cases, synchronous gastric cancers were detected in 31 cases (2.0%). Of these 31 cases, 26 had early gastric cancer (EGC; 83.9%) and 5 had advanced gastric cancer. Ten (38.5%) of the 26 EGC cases were managed using endoscopic mucosal resection. Compared to colorectal cancer patients without synchronous gastric cancer, the group of patients with synchronous gastric cancer was older (65.5+/-9.6 vs 58.4+/-11.3 years, p=0.001) and had a greater proportion of males (77.4 vs 59.4%, p=0.043).

CONCLUSION

This study found that 2% of Korean sporadic colorectal cancer patients had synchronous gastric cancer. A preoperative EGD for colorectal cancer patients is likely to greatly assist in the diagnosis of synchronous gastric cancer at an early stage and the implementation of appropriate minimally invasive treatment.

Aspergillus oryzae palBory encodes a calpain-like protease: homology to Emericella nidulans PalB and conservation of functional regions

We have cloned and sequenced genomic DNA of Aspergillus oryzae palBory, orthologue of Emericella nidulans palB, which encodes a calpain-like protease modulating a signal transduction pathway during alkaline adaptation. The deduced amino acid sequence of PalBory is 70.0% identical to PalB over its entire length. The regions with high similarity revealed possible domains important for their function. This is the first step towards understanding the alkaline adaptation mechanism of A. oryzae, which would be very useful in the fermentation industry.

Use of polyurethane with sustained release dexamethasone in delayed adjustable strabismus surgery

AIM

To determine the effect of polyurethane film with sustained release dexamethasone (SRD) in delayed adjustable strabismus surgery.

METHODS

A prospective, masked observer, controlled study was performed in rabbits. Thirty four rabbit eyes were divided into three groups. After recession of the superior rectus muscle (SRM), polyurethane film with or without SRD, or balanced salt solution was applied beneath and over SRM in the polyurethane-dexamethasone group (group P-D), polyurethane group (group P), and the control group (group C), respectively. Delayed adjustment was performed once on each SRM at 4 and 6 weeks postoperatively by a masked observer. The possible length to adjust and the necessary force required for the adjustment, as well as the degree of any adhesions, were also evaluated.

RESULTS

In the control group, adjustment was impossible in all of the eyes at 4 and 6 weeks postoperatively. In group P-D, adjustment was possible in 11 out of 11 eyes (11/11) 4 weeks postoperatively and in 10/11 eyes 6 weeks postoperatively. In group P, adjustment was possible in 9/11 eyes 4 weeks postoperatively and in 10/12 eyes 6 weeks postoperatively.

CONCLUSIONS

Use of polyurethane film with and without SRD could delay adjustment in most eyes for up to 6 weeks postoperatively. Polyurethane is helpful for delaying adjustment in rabbit eyes until 6 weeks postoperatively without the need for frequent topical instillation of steroids.