Synthesis of cuprous oxide/silver (Cu2O/Ag) hybrid as surface-enhanced Raman scattering probe for trace determination of methyl orange.

Recently, there have been publications on preparing hybrid materials between noble metal and semiconductor for applications in surface-enhanced Raman scattering (SERS) substrates to detect some toxic organic dyes. However, the use of cuprous oxide/silver (Cu2O/Ag) to measure the trace amounts of methyl orange (MO) has not been reported. Therefore, in this study, the trace level of MO in water solvent was determined using a SERS substrate based on Cu2O microcubes combined with silver nanoparticles (Ag NPs). Herein, a series of Cu2O/Agx (x= 1-5) hybrids with various Ag amounts was synthesized via a solvothermal method followed by a reduction process, and their SERS performance was studied in detail. X-ray diffraction (XRD) and scanning electron microscopy results confirmed that 10 nm Ag NPs were well dispersed on 200-500 nm Cu2O microcubes to form Cu2O/Ag heterojunctions. Using the as-prepared Cu2O and Cu2O/Agx as MO probe, the Cu2O/Ag5 nanocomposite showed the highest SERS activity of all samples with the limit of detection as low to 1 nM and the enhancement factor as high as 4 × 108. The logarithm of the SERS peak intensity at 1389 cm-1 increased linearly with the logarithm of the concentration of MO in the range from 1 nM to 0.1 mM.

Effect of the non-ideal axial ratio c/a on anharmonic EXAFS oscillation of h.c.p. crystals.

The temperature and wavenumber dependence of the extended X-ray absorption fine-structure (EXAFS) oscillation of hexagonal close-packed (h.c.p.) crystals have been calculated and analyzed under the effect of the non-ideal axial ratio c/a. The anharmonic EXAFS oscillation is presented in terms of the Debye-Waller factor using the cumulant expansion approach up to the fourth order. An effective calculation model is expanded and developed from the many-body perturbation approach and correlated Debye model using the anharmonic effective potential. This potential, depending on the non-ideal axial ratio c/a, is obtained from the first-shell near-neighbor contribution approach. A suitable analysis procedure is performed by evaluating the influence of EXAFS cumulants on the phase shift and amplitude reduction of the anharmonic EXAFS oscillation. The numerical results for crystalline zinc are found to be in good agreement with those obtained from experiments and other theoretical methods at various temperatures. The obtained results show that the present theoretical model is essential and effective in improving the accuracy for analyzing the experimental data of anharmonic EXAFS signals of h.c.p. crystals with a non-ideal axial ratio c/a.

Transillumination-assisted orotracheal intubation: a comparison of the Bonfils fibrescope and the lightwand (Trachlight).

BACKGROUND: Because the Bonfils fibrescope has a semi-rigid optical stylet and is similar in shape to a lightwand, we aimed to evaluate and compare the efficacy of transillumination-assisted orotracheal intubation with the Bonfils fibrescope and the Trachlight(TM) lightwand in patients with normal airways. METHODS: As a preliminary investigation to form a basis for later studies, therefore, we performed a randomized, single-blind study of 300 patients with normal airways to compare the efficiency of Trachlight and transillumination-assisted Bonfils orotracheal intubation in these patients. In both groups, orotracheal intubation was performed using a transillumination technique. The first attempt and overall success rates of tracheal intubation, the times required, and any untoward effects were recorded. RESULTS: Although the overall success rates were similar for Bonfils and Trachlight intubations (97.3% and 98.7%, respectively), tracheal intubation was successful on the first attempt in 87.3% of patients with the Bonfils fibrescope compared with 95.3% of patients with the Trachlight (P < 0.05). The mean intubation time for the first attempt was 15 ± 5 s with the Bonfils fibrescope and 9 ± 2 s with the Trachlight (P < 0.001). Patients intubated using the Bonfils fibrescope also experienced significantly more sore throat and hoarseness than those intubated using the Trachlight. CONCLUSIONS: For patients with normal airways, the Trachlight is superior for orotracheal intubation with respect to reliability, rapidity, and safety compared with the Bonfils fibrescope used with the transillumination technique.

The effects of obesity and HER-2 polymorphisms as risk factors for endometrial cancer in Korean women.

OBJECTIVE: To evaluate the relationship between single nucleotide polymorphisms (SNPs) in the HER-2 gene, body mass index (BMI) and the risk of endometrial cancer. DESIGN: Case-control study. SETTING: Medical centres in Korea. SAMPLE: DNA samples and medical histories were obtained from 125 endometrial cancer cases and 302 controls. METHODS: The genotypes evaluated in HER-2 at positions -423, -655, -776, -857, -1170, -1177, -1253 of the coding region and two SNPs located in an intron by SNP-IT assay using SNPstream Ultra-high throughput system. MAIN OUTCOME MEASURES: Odd ratio for endometrial cancer associated with HER-2 polymorphisms and BMI. RESULTS: Cases had a significantly higher BMI than controls and the obese subjects had a 2.65-fold increased risk for endometrial cancer. However, HER-2 polymorphism was not associated significantly with the risk of endometrial cancer. Subjects with BMI > or = 25 kg/m2 who carried rs1801200 AA, rs1801200 GA/GG, rs1810132 CT/CC, rs2517951 CT/TT and rs1058808 CG/GG genotype had significantly increased risk of endometrial cancer than subjects with a normal BMI (P for linear trend <0.05). However, the risk in the subjects with the variant allele for HER-2 genotypes did not differ significantly compared to those with homozygous wild-type allele within specific BMI subgroups. CONCLUSIONS: Endometrial cancer risk increased significantly in proportion to BMI. However, HER-2 polymorphism did not affect significantly on the risk of endometrial cancer.

Observation of "Ghost" islands and surfactant effect of surface gallium atoms during GaN growth by molecular beam epitaxy

We observe "ghost" islands formed on terraces during homoepitaxial nucleation of GaN. We attribute the ghost islands to intermediate nucleation states, which can be driven into "normal" islands by scanning tunneling microscopy. The formation of ghost islands is related to excess Ga atoms on the surface. The excess Ga also affect island number density: by increasing Ga coverage, the island density first decreases, reaching a minimum at about 1 monolayer (ML) Ga and then increases rapidly for coverages above 1 ML. This nonmonotonic behavior points to a surfactant effect of the Ga atoms.