Efficient optical coupling in AlGaN/GaN quantum well infrared photodetector via quasi-one-dimensional gold grating

In this letter, a new kind of grating, quasi-one-dimensional gold grating, has been proposed to enhance the optical coupling in AlGaN/GaN quantum well infrared photodetector (QWIP). The electric field distribution, current density and energy flow are analyzed by an algorithm of finite element method (FEM). Significantly enhanced electric field component E(z) perpendicular to multiple quantum wells (MQWs) is explained by introducing the resonant coupling of surface plasmon polariton (SPP) and localized surface plasmon (LSP). The |E(z)|(2) in MQWs reaches 0.85 (V/m(2) when the electric field intensity (|E(0)|(2)) of normal incidence is 1 (V/m(2) at 4.65 μm, showing 2 times and 1.3 times increase compared with that obtained via a one-dimensional gold grating and a two-dimensional gold grating, respectively. The results confirm that the quasi-one-dimensional gold grating provides more plasma excitation source and higher charge density with structure optimization, resulting in a high optical coupling efficiency of 85% in quantum well region.

New onset diabetes after transplantation: Not another acronym!

New onset diabetes after transplantation is the onset of diabetes in previously non-diabetic individuals extending beyond the first month post-transplantation.

Recombinant human thyrotropin versus thyroid hormone withdrawal in radioiodine remnant ablation for differentiated thyroid cancer: a meta-analysis

AIM

We aim to assess the effects of recombinant human thyrotropin (rhTSH) versus thyroid hormone withdrawal (THW), and rhTSH-aided low doses (1.11 GBq and 1.85 GBq) versus high dose (3.7 GBq) of radioiodine in the residual ablation for differentiated thyroid cancer (DTC).

METHODS

Studies were obtained from computerized searches of MEDLINE, EMBASE, the Cochrane Library (all until September 2012). Randomized controlled trials were included.

RESULTS

Altogether 1325 patients with DTC participated in seven trials for residual ablation. Overall, studies had a low risk of bias. We found no statistically significant differences between rhTSH and THW treatment in terms of successful ablation rate (OR 0.87, 95% CI 0.56 to 1.37, P=0.56) but significant benefits in health-related quality of life (mean difference 3.59, 95% CI 2.81 to 4.37, P<0.00001), adverse events during and after ablation (OR 0.57, 95% CI 0.44 to 0.73, P<0.00001), radiation exposure to blood and bone marrow (mean difference -0.01, 95% CI -0.02 to -0.01, P<0.00001). In addition, no significant difference was found in the successful ablation rate between the low dose (1.11 GBq and 1.85 GBq) and high dose (3.7 GBq) of radioiodine aided by rhTSH (OR 0.85, 95% CI 0.49 to 1.47, P=0.56). There were no deaths and no serious adverse effects in DTC patients treated with either rhTSH or THW, maximum follow-up was 12 months. None of the included trials investigated secondary malignancies or economic outcomes.

CONCLUSION

rhTSH is as effective as THW on radioiodine thyroid remnant ablation with significant benefits on health-related quality of life, adverse effects during and after ablation, decreased whole body radiation exposure. The lower radioiodine doses are as effective as high doses for remnant ablation under rhTSH stimulation.

Bone turnover markers predict hip bone loss in elderly European men: results of the European Male Ageing Study (EMAS)

SUMMARY

The aim of this study was to determine whether bone turnover markers (BTMs) predict changes in areal bone mineral density (aBMD) in middle-aged and elderly European men. Older men with high bone turnover are at a higher risk of accelerated hip bone loss, but the clinical utility of BTMs in individuals is limited.

INTRODUCTION

Prospective studies on the value of BTMs to predict changes in aBMD in men are few and conflicting. The aim of this study was to determine whether BTMs predict changes in aBMD in middle-aged and elderly European men.

METHODS

In 487 men aged 40-79 years from the European Male Ageing Study (EMAS), BTMs were assessed at baseline and dual-energy X-ray absorptiometry (DXA) at the lumbar spine (LS), femoral neck (FN) and total hip (TH) was performed at baseline and after a mean follow-up of 4.3 years.

RESULTS

The mean aBMD decreased by 0.32%/year at FN and 0.22%/year at TH and increased by 0.32%/year at LS. Higher baseline levels of β C-terminal cross-linked telopeptide (β-CTX) and N-terminal propeptide of type I procollagen (PINP) were significantly associated with higher loss of hip aBMD in the whole cohort and men aged 60-79 years. These associations remained significant after adjustment for age, centre and body mass index (BMI). Men aged 60-79 years with β-CTX in the upper quintile were more likely of being in the upper quintile of annual percentage (%) aBMD loss at FN (OR=4.27; 95% CI=2.09-8.73) and TH (OR=3.73; 95% CI=1.84-7.57). The positive predictive value (PPV) was 46% at both hip sites.

CONCLUSION

Older men with high bone turnover have a higher risk of accelerated hip bone loss, but the PPV is low. BTMs are therefore unlikely to be of clinical utility in predicting accelerated hip bone loss in individual subjects.

Global impacts of aflatoxin in maize: trade and human health

Maize is one of the most important agricultural commodities worldwide in terms of amounts produced, consumed, and traded. Hence, naturally occurring aflatoxin contamination in maize has important ramifications for both global trade and health. Aflatoxin is produced by certain species of the genus Aspergillus in a variety of food crops, including maize, peanuts, and tree nuts. Over 100 nations have aflatoxin regulations, which are intended to protect human and animal health, but also incur economic losses to nations that attempt to export maize and other aflatoxin-contaminated commodities. These economic effects must be balanced against the health protection afforded by the regulations. It is important to acknowledge that, even in nations that have aflatoxin regulations, many individuals consume maize that has undergone no regulatory inspection, especially in nations where subsistence farming is widespread. Hence, aflatoxin contamination, exposure, and lack of regulation can also contribute to adverse effects on trade and health worldwide. This review, part of a special issue on aflatoxin in maize, describes economic and health effects of aflatoxin in maize on a global level. It ends with a story of an intervention that reduced maize consumption in one population in China, which is likely the main determinant of the reduction in liver cancer mortality in that population over the last 30 years, from reduced aflatoxin exposure.

Modification of properties of yttria stabilized zirconia epitaxial thin films by excimer laser annealing

This study focuses on the ultrafast improvement of surface wettability, electrical, and room temperature magnetic characteristics of cubic zirconia single crystalline thin films after laser annealing. The point defects generated by the laser treatment are envisaged to play a critical role in altering the above properties. Yttria stabilized zirconia (YSZ) thin films were epitaxially grown on Si(100) substrates by pulsed laser deposition technique and subsequently annealed by a KrF excimer laser beam (τ = 25 ns) using low-energy laser pulses. An atomically sharp interface, parallel to the film free surface, between laser annealed layer and the pristine region was observed. The single crystalline nature of thin films was preserved following the laser treatment. The laser-solid interaction with YSZ led to the introduction of point defects, i.e., oxygen vacancies, resulting in a strained structure which, in turn, resulted in the formation of a tetragonal-like zirconia. With the increase of number of laser pulses the laser treated films got highly disordered due to the high concentration of the point defects, while maintaining their crystalline nature. Although the surface of the pristine sample showed weak hydrophilic characteristics (contact angle ∼ 73°), the laser annealed samples exhibited significantly improved hydrophilic characteristics. It was found that there is an optimum number of laser pulses where the maximum hydrophilicity (contact angle ∼ 22°) is obtained. The carrier concentration in the sample with the highest hydrophilicity was determined to be higher by about 5 orders of magnitude compared to the pristine sample. This sample possessed the lowest electrical resistivity. The laser annealed YSZ epilayers showed a superior room-temperature ferromagnetic behavior, compared to the pristine samples. A 2-fold enhancement in the magnetization of the samples was observed following the laser treatment which is a clear demonstration of the key role of defects and their transient distribution throughout the lattice. All these observations were correlated with the formation of point defects due to the photon interaction with YSZ and absorption of energy of the KrF laser photons to produce defects.

Comparative numerical-experimental analysis of the universal impact of arbitrary perturbations on transport in three-dimensional unsteady flows

Numerical studies of three-dimensional (3D) time-periodic flow inside a lid-driven cylinder revealed that a weak perturbation of the noninertial state (Reynolds number Re=0) has a strong impact on the Lagrangian flow structure by inducing transition of a global family of nested spheroidal invariant surfaces into intricate coherent structures consisting of adiabatic invariant surfaces connected by tubes. These tubes provide paths for passive tracers to escape from one invariant surface to another. Perturbation is introduced in two ways: (i) weak fluid inertia by nonzero Re∼O(10(-3)); (ii) small disturbance of the external flow forcing. Both induce essentially the same dynamics, implying a universal response in the limit of a weak perturbation. Moreover, we show that the motion inside tubes possesses an adiabatic invariant. Long-term experiments were conducted using 3D particle-tracking velocimetry and relied on experimental imperfections as natural weak perturbations. This provided first experimental evidence of the tube formation and revealed close agreement with numerical simulations. We experimentally validated the universality of the perturbation response and, given the inevitability of imperfections, exposed the weakly perturbed state as the true "unperturbed state" in realistic systems.

Rotenone impairs autophagic flux and lysosomal functions in Parkinson's disease

BACKGROUND

Rotenone is an environmental neurotoxin that induces accumulation of α-synuclein and degeneration of dopaminergic neurons in substantia nigra pars compacta (SNpc), but the molecular mechanisms are not fully understood. We investigated whether rotenone induced impairment of autophagic flux and lysosomal functions.

METHODS

Autophagy flux, accumulation of α-synuclein, lysosomal membrane integrity and neurodegeneration were assessed in the rotenone-treated rat model and PC12 cells, and the effects of the autophagy inducer trehalose on rotenone's cytotoxicity were also studied.

RESULTS

Rotenone administration significantly reduced motor activity and caused a loss of tyrosine hydroxylase in SNpc of Lewis rats. The degeneration of nigral dopaminergic neurons was accompanied by the deposition of α-synuclein aggregates, autophagosomes and redistribution of cathepsin D from lysosomes to the cytosol. In cultured PC12 cells, rotenone also induced increases in protein levels of α-synuclein, microtubule-associated protein 1 light chain 3-II, Beclin 1, and p62. Rotenone increased lysosomal membrane permeability as evidenced by leakage of N-acetyl-beta-d-glucosaminidase and cathepsin D, the effects were blocked by reactive oxygen species scavenger tiron. Autophagy inducer trehalose enhanced the nuclear translocation of transcription factor EB, accelerated the clearance of autophagosomes and α-synuclein and attenuated rotenone-induced cell death of PC12 cells. Meanwhile, administration of trehalose to rats in drinking water (2%) decreased rotenone-induced dopaminergic neurons loss in SNpc.

CONCLUSIONS

These studies indicate that the lysosomal dysfunction contributes to rotenone's neurotoxicity and restoration of lysosomal function could be a new therapeutic strategy for Parkinson's disease.

Inducible nitric oxide inhibitor enhances the anti-tumor effect of cisplatin on CNE-2 cells by inducing cell apoptosis

OBJECTIVE

Inducible nitric oxide (NO) synthase (iNOS) inhibitor S-methylisothiourea (SMT) has been reported to have anti-tumor effects on several types of cancers.  We aimed to investigate whether SMT can inhibit nasopharyngeal carcinoma cells CNE-2 proliferation through raise chemotherapy effect of diaminodichloroplatinum (DDP).

MATERIALS AND METHODS

CNE-2 cells were treated with SMT, DDP and both of them respectively. MTT and colony-forming assay was performed to detect the proliferation effect of the treatment. Hoechst 33258 staining and apoptosis analysis were performed to investigate the apoptosis effect of chemotherapy. Additionally, the NO level was detected to estimate the activity of iNOS.

RESULTS

CNE-2 cells expressed high level of iNOS. SMT can inhibit CNE-2 cells growth in a dose-dependent manner and have the effect on reducing dosage of DDP as well as enhancing the anti-tumor efficacy by promote cell apoptosis.

CONCLUSIONS

Our findings suggested that SMT play a synergism role in the inhibition process of DDP on nasopharyngeal carcinoma, and SMT could be a promising therapeutic factor for cancer prevention.

Effects of a recovery management intervention on Chinese heroin users' community recovery through the mediation effect of enhanced service utilization

BACKGROUND

This study investigates whether a recovery management intervention (RMI) can improve the utilization of community drug treatment and wraparound services among heroin users in China and subsequently lead to positive recovery outcomes.

METHODS

Secondary analysis was conducted drawing data from a randomized controlled trial; 100 heroin users with no severe mental health problems were recruited in two Shanghai districts (Hongkou and Yangpu) upon their release from compulsory rehabilitation facilities. A latent variable modeling approach was utilized to test whether the RMI influences heroin users' perceived motivation and readiness for treatment, enhances treatment and wraparound service participation, and, in turn, predicts better recovery outcomes.

RESULTS

Enrollment in drug treatment and other social service utilization increased significantly as a result of RMI rather than an individual drug user's motivation and readiness for treatment. Increased service utilization thus led to more positive individual recovery outcomes. In addition to this mediation effect through service utilization, the RMI also improved participants' community recovery directly.

CONCLUSIONS

Findings suggest that better drug treatment enrollment, community service utilization and recovery outcomes can be potentially achieved among heroin users in China with carefully designed case management interventions.

Limited human-to-human transmission of avian influenza A(H7N9) virus, Shanghai, China, March to April 2013

In April 2013, two members of one family were successively confirmed as cases of avian influenza A(H7N9) virus infection in Shanghai, China. Respiratory specimens from the two cases and their close contacts were tested using real-time reverse-transcription (RT)-PCR. Paired serum specimens from contacts were tested by haemagglutination inhibition assay and microneutralisation test. The index patient developed severe pneumonia. Her husband presented with pneumonia shortly thereafter. Both cases had highly similar clinical features and infection with A(H7N9) virus was confirmed in both cases by genetic analysis. Phylogenetic analysis revealed a high level of similarity between the sequences from the two patients and environmental samples collected from wet markets in Minhang and Changning districts. Six samples from the Changning wet market were confirmed as A(H7N9) positive. Of 27 close contacts, one developed mild respiratory symptoms and another tested positive for A(H7N9) antibodies, but both were negative by real-time RT-PCR. The other 25 close contacts of both cases were A(H7N9) negative. Limited human-to-human transmission of the virus most likely occurred in the family cluster. However, other close contacts did not test positive for the virus, suggesting limited potential for extensive human-to-human transmission of the virus.

Double-resonance enhanced intersubband second-order nonlinear optical susceptibilities in GaN/AlGaN step quantum wells

Second-order nonlinear optical susceptibilities for second harmonic generation (SHG) associated with intersubband transitions in GaN/AlGaN single quantum well and step quantum well have been studied theoretically by solving Schrödinger and Poisson equations self-consistently. The calculated results suggest that due to the very large polarization-induced field in the quantum well, the potential profile becomes asymmetrical, leading to large second-order susceptibilities. A high value about 4 × 10^-7 m/V can be obtained in single quantum well structure. Furthermore, by adopting step quantum well structure to increase the asymmetry degree of the potential profile and manipulate the energy levels for double-resonance, a significant enhancement of second-order susceptibility can occur in step quantum well. Specifically, the susceptibility can be as large as 4 × 10^-6 m/V with structure optimization, about an order of magnitude greater than that in single quantum well. The results indicate that nonlinear optical elements based on GaN/AlGaN step quantum wells are very promising for SHG in a wide range of wavelengths from telecommunication to mid-infrared, especially effective in longer wavelength.

Submandibular gland sparing in intensity-modulated radiotherapy for N0-stage nasopharyngeal carcinoma

OBJECTIVE

This study evaluated and quantified the feasibility of submandibular gland (SMG) sparing in intensity-modulated radiotherapy (IMRT) for N0-stage nasopharyngeal carcinoma (NPC).

METHODS

Ten patients with N0-stage NPC were enrolled in the study. Four IMRT plans were produced for each, with different limiting conditions. In plan A, SMG sparing was ignored; in plans B, C and D, the mean dose to SMGs was restricted to 39 Gy. In addition, at least 95% of planning target volume (PTV)-IIa (PTV of clinical target volume involving level IIa lymph node) in plan C and 90% of PTV-IIa in plan D were required to have a 60 Gy covering.

RESULTS

The average mean dose to SMGs was 54.6 ± 3.6 Gy in plan A and was lower 39.3 ± 0.3, 49.3 ± 1.9 and 46.7 ± 2.8 Gy in plans B, C and D, respectively. The volume of PTV-IIa covered by 60 Gy was 98.9%, 81.6%, 95.2% and 90.8% in plans A, B, C and D, respectively, and showed a parallel association between dose reduction to SMGs and the covering deficit of PTV-IIa.

CONCLUSION

Reducing the mean dose received by SMG to 39 Gy or less in IMRT for N0-stage NPC is feasible.