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Random-distributed gold nanorod arrays (R-GNRAs) deposited on glass substrates have been systematically investigated through Z-scan, second harmonic generation (SHG), and dichromatic pump–probe mea...

Size and operating energy are two key parameters that constrain the integration capability of a nonlinear optical device. Here, we report a 60 nm thin film made of randomly distributed gold nanorod...

Many features are shared between esophageal cancer (EC) and gastric cancer (GC). This study aimed to explore whether known EC susceptibility loci are also important in the development of GC. A total of 21 genetic variants associated with EC in genome-wide association studies were evaluated with association of GC risk in 2631 cases and 4373 controls of Chinese ancestry. Single variant and weighted genetic scores (WGS) for esophageal squamous cell carcinoma (ESCC), esophageal adenocarcinoma (EAC), and overall EC were analyzed with GC risk, respectively. Genetic variants of rs2274223 in PLCE1 at 10q23.33 (per G allele: odds ratio (OR) = 1.26, 95% confidence interval (CI): 1.16–1.38, P = 6.51 × 10−8), rs10052657 in PDE4D at 5q11.2 (per C allele: OR = 1.12, 95% CI: 1.01–1.25, P = 3.28 × 10−2) and rs671 in ALDH2 at 12q24.12 (per A-allele: OR = 0.83, 95% CI: 0.75–0.91, P = 1.14 × 10−4) were significantly associated with GC risk. The combined effect of those three variants had stronger influence on GC risk (OR = 1.31, 95% CI: 1.19–1.44, P = 2.34 × 10−8). High WGS of ESCC was also associated with increased risk of GC (P = 5.52 × 10−4 as a continuous variable) (trend test P = 2.71 × 10−4), whereas no statistically significant associations were observed between the WGS of EAC and GC risk (P = 0.66 as a continuous variable) (trend test P = 0.70). ESCC rather than EAC may share genetic susceptibility with GC. Genetic variants at 10q23.33, 5q11.2, and 12q24.12 may be useful as biomarkers to identify individuals with high risk for both ESCC and GC.

The third-order optical nonlinearities and the hot electron relaxation time (τ) of random-distributed gold nanorods arrays on glass (R-GNRA) have been investigated by using Z-scan and optical Kerr effect (OKE) techniques. Large third-order optical susceptibility (χ(3)) with the value of 2.5 × 10-6 esu has been obtained around the plamsonic resonance peak under the excitation power intensity of 0.1 GW/cm2. Further decrease of the excitation power intensity down to 0.3 MW/cm2 will lead to the significant increase of χ(3) up to 6.4 × 10-4 esu. The OKE results show that the relaxation time of R-GNRA around the plasmonic peak is 13.9 ± 0.4 ps, which is more than 4 times longer than those of the individual gold nanostructures distributed in water solutions. The Finite-difference time domain simulations demonstrate that this large enhancement of χ(3) and slow down of τ are caused by the gap-induced large local field enhancement of GNRs dimers in R-GNRA. These significant results offer great opportunities for plasmonic nanostructures in applications of photonic and photocatalytic devices.

We demonstrate broadband photoluminescence (PL) from a Au nanorod–alumina–Al substrate (Au–Al2O3–Al) sandwich structure under a peak excitation power intensity of 1.45–2.61 GW cm−2. The emission wavelength is in the range of 450–1050 nm and the lifetime is on the sub-nanosecond timescale. Comparative studies of the PL from Au–Al2O3–Al with different Au rod lengths and Au–Al2O3 without an Al coupling layer, together with finite difference time domain (FDTD) calculations, show that the PL from Au–Al2O3–Al originates from the surface plasmon enhanced supercontinuum (SC) generation in the Al2O3 membrane. This observation indicates that a SC could be realized in nanoscale plasmonic structures, which has promising applications in the minimization and integration of light sources in photonic devices.

Plasmonic nanostructures with sub-10 nm gaps possess intense electric field enhancements, leading to their high reputation for exploring various functional applications at nanoscale. Till now, although large amounts of efforts have been devoted into investigation of such structures, few works were emphased on the nonlinear optical properties in near-ultraviolet (UV) region. Here, by combining sputtering technique and an optimized anodic aluminum oxide (AAO) template growing method, we obtain aluminum (Al) nanorod array film (NRAF) with average rod diameter and gap size of 50 and 7 nm, respectively. The Al-NRAF exhibits large third-order optical nonlinear susceptibility (χ(3)) and high figure of merit (χ(3)/α) over a broad wavelength range from 360 to 900 nm, and reaches their maximums at the shortest measured wavelength. In addition, comparisons with Au-NRAF and Ag-NRAF samples further confirm that Al-NRAF has better nonlinear optical properties in the blue and near-UV wavelength regions. These results indicate that Al nanostructures are promising candidates for nonlinear plasmonic applications at blue and near-UV wavelengths.

A low-cost, broadband white-light source based on Au nanorod-aluminum oxide (Au-AAO) nanostructures was obtained and used for micro-spectroscopy measurement. When an Au-AAO sample was excited by using a continuous-wave or a pulsed laser, smooth and broadband strong photoluminescence from 550 nm to 1560 nm could be achieved. A high-quality transmission spectrum was obtained from few-layer MoS2 flakes using Au-AAO as the illuminating source, demonstrating the suitability of the Au-AAO nanostructure as a light source for spectroscopy. This accomplishment is significant and provides a potential new white-light source for applications in bio-sensing and spectroscopy on the microscale.

A broadband all-optical switch based on the thermal lens effect of InP/ZnS quantum dots (QDs) has been demonstrated. Using a pump laser at 600 nm, whose photon energy is larger than the bandgap, thermal effects induce a large nonlinear optical refraction that modulates the beam path of a probe light to form an all-optical switch. By adjusting the sizes of the QDs, the position of the bandgap can be tuned over a wide wavelength range. Thus, both the pump and the probe wavelengths can be designed for specific applications. The on/off tests of the all-optical switches demonstrate that they work well with switching rates of hundreds of Hertz. Our result demonstrates that InP/ZnS quantum dots are a good candidate material for the application of all-optical switching.A broadband all-optical switch based on the thermal lens effect of InP/ZnS quantum dots (QDs) has been demonstrated. Using a pump laser at 600 nm, whose photon energy is larger than the bandgap, thermal effects induce a large nonlinear optical refraction that modulates the beam path of a probe light to form an all-optical switch. By adjusting the sizes of the QDs, the position of the bandgap can be tuned over a wide wavelength range. Thus, both the pump and the probe wavelengths can be designed for specific applications. The on/off tests of the all-optical switches demonstrate that they work well with switching rates of hundreds of Hertz. Our result demonstrates that InP/ZnS quantum dots are a good candidate material for the application of all-optical switching.

Background: First-line triple therapy with levofloxa- cin and amoxicillin plus a proton pump inhibitor has been reported to be effective and well tolerated in the eradication of Helicobacter pylori infection. Studies have reported that cytochrome P450 (CYP) 2C19 genotypes may affect the clinical efficacy of clarithromycinbased triple therapies, although there is only one report of such an effect with levofloxacin-based triple therapies. Objectives: This study evaluated the clinical efficacy and tolerability of a 1-week course of triple therapy with levofloxacin and amoxicillin plus esomeprazole or rabeprazole as first-line treatment for H pylori infection in Chinese adults. It also investigated whether CYP2C19 genotype status affected rates of H pylori eradication with these regimens. Methods: Consecutive patients undergoing upper endoscopy at the First Affiliated Hospital of Nanjing Medical University between May 2008 and January 2009 were evaluated for inclusion. Eligible patients were those who tested positive for H pylori infection on biopsy-based testing (ie, histology and an in-house rapid urease test) or a validated 13 C-urea breath test. Patients were randomized in an open-label fashion to receive levofloxacin 500 mg/d and amoxicillin 1000 mg BID plus either esomeprazole 20 mg BID (group A), esomeprazole 40 mg BID (group B), or rabeprazole 10 mg BID (group C) for 1 week. Patients were asked to record adverse events in a diary. Trained study assistants contacted patients by telephone within the first week after completion of therapy to collect data on drug compliance and adverse events. H pylori status was determined 4 weeks after the end of therapy using a 13 C-urea breath test. Rates of H pylori eradication were calculated in the intent-to-treat (ITT) and per-protocol (PP) populations. CYP2C19 genotype was determined by the polymerase chain reaction-restriction fragment-length polymorphism method. Results: Of 199 consecutive patients screened for eligibility, 184 H pylori -positive patients were enrolled in the study (61 in group A, 62 in group B, and 61 in group C). The overall sample was balanced in terms of age, sex, endoscopic diagnosis, and history of smoking. Rates of H pylori eradication in the ITT and PP populations were as follows: group A—85.2% (52/61) and 86.7% (52/60), respectively; group B—87.1% (54/62) and 90.0% (54/60); and group C—75.4% (46/61) and 75.4% (46/61). There were no significant differences in eradication rates among groups, nor were there any differences in rates of compliance (98.4%, 96.8%, and 100% in groups A, B, and C, respectively) or adverseevent profiles. Fifteen patients (7.6%) reported adverse events during the study (5 [8.2%] in group A, 6 [9.7%] in group B, and 4 [6.6%] in group C). The adverse events included diarrhea (6 patients), dizziness (5), abdominal pain (2), nausea (1), and skin rash (1). Three patients discontinued treatment because of adverse events ( 1 due to skin rash in group A and 2 due to dizziness in group B). In the 147 patients included in the PP analysis of the effect of CYP2C19 genotype, eradication rates were 88.9% (32/36) in poor metabolizers, 82.0% (50/61) in heterozygous extensive metabolizers, and 82.0% (41/50) in homozygous extensive metabolizers. Eradication rates did not differ significantly among genotype groups. Conclusions: One week of first-line triple therapy with levofloxacin and amoxicillin plus esomeprazole 20 or 40 mg BID or rabeprazole 10 mg BID was associated with H pylori eradication rates of 85.2%, 87.1%, and 75.4%, respectively, with no significant differences between treatment groups. There were no significant differences in eradication of H pylori by CYP2C19 genotype in this small population of Chinese adults.

Surface plasmonic systems provide extremely efficient ways to modulate light-matter interaction in photon emission, light harvesting, energy conversion and transferring, etc. Various surface plasmon enhanced luminescent behaviors have been observed and investigated in these systems. But the origin of an avalanche-like photoluminescence, which was firstly reported in 2007 from Au and subsequently from Ag nanowire arrays/monomers, is still not clear. Here we show, based on systematic investigations including the excitation power/time related photoluminescent measurements as well as calculations, that this avalanche-like photoluminescence is in fact a result of surface plasmon assisted thermal radiation. Nearly all of the related observations could be perfectly interpreted with this concept. Our finding is crucial for understanding the surface plasmon mediated thermal and photoemission behaviors in plasmonic structures, which is of great importance in designing functional plasmonic devices.

Au–Ag core–shell nanorods with surface plasmon resonance wavelengths of 760–840 nm were prepared. Wavelength-dependent nonlinear absorption coefficients (β) and nonlinear refractive indices (γ) of the nanorods were measured by using Z-scan techniques. The corresponding one-photon and two-photon figures of merit (W and T) were calculated from β and γ. The results show that the requirements of W > 1 and T < 1 for the application of all-optical switching could be achieved for all the samples over a broad wavelength range. These observations make the Au–Ag core–shell nanorods a good candidate for all-optical switching devices.