Electric field enhancement and concomitant Raman spectral effects at the edges of a nanometre-thin gold mesotriangle

The local electric field enhancement at various regions of an individual nanometre-thin gold mesotriangle has been demonstrated both numerically and experimentally. This work provides, for the first time, direct experimental evidence of localized enhancement of Raman signals at three edges of nanometre-thin gold mesotriangles at single particle level, using Raman microscopy. Raman images were collected from mesotriangles of ~11 mm edge length and ~30 nm thickness, using adsorbed crystal violet as the probe molecule. Spatial distribution and the extent of electric field enhancement around a single mesotriangle are investigated theoretically by finite-difference time-domain (FDTD) simulations. Confocal Raman studies provided direct proof for the substantial electrical field enhancement at the edges and corners compared to the face of the mesotriangle. The simulated electric field enhancement was in the order, corner > edge > surface, which is in complete agreement with the experimental results

IMECE2009-10157 Contact Time Study of Microsystems Actuated by Ramp-Input Voltages

ABSTRACT This paper presents a model to analyze contact phenomenon in microsystems, actuated by ramp voltages, which has applications in frequency sweeping. First-order shear deformation theory is used to model dynamical system using finite element method, while finite difference method is applied to model squeeze film damping. The model is validated by static pull-in results. The presented hybrid FEM-FDM model is utilized to compute values of contact time and dynamic behavior. Considering this model, effects of different geometrical and mechanical parameters on contact time are studied. The influence of imposing the additional reverse voltage on dynamic characteristics of the system is also investigated. It is shown that magnitude and position of applying the reverse voltage is very important in preventing pull-in instability

Applying GRADE-CERQual to qualitative evidence synthesis findings-paper 7: Understanding the potential impacts of dissemination bias

This is the final version. Available from BMC via the DOI in this record. Additional materials are available on the GRADE-CERQual website (www.cerqual.org).Background: The GRADE-CERQual (Confidence in Evidence from Reviews of Qualitative research) approach has been developed by the GRADE (Grading of Recommendations Assessment, Development and Evaluation) Working Group. The approach has been developed to support the use of findings from qualitative evidence syntheses in decision-making, including guideline development and policy formulation. CERQual includes four components for assessing how much confidence to place in findings from reviews of qualitative research (also referred to as qualitative evidence syntheses): (1) methodological limitations, (2) coherence, (3) adequacy of data and (4) relevance. This paper is part of a series providing guidance on how to apply CERQual and focuses on a probable fifth component, dissemination bias. Given its exploratory nature, we are not yet able to provide guidance on applying this potential component of the CERQual approach. Instead, we focus on how dissemination bias might be conceptualised in the context of qualitative research and the potential impact dissemination bias might have on an overall assessment of confidence in a review finding. We also set out a proposed research agenda in this area. Methods: We developed this paper by gathering feedback from relevant research communities, searching MEDLINE and Web of Science to identify and characterise the existing literature discussing or assessing dissemination bias in qualitative research and its wider implications, developing consensus through project group meetings, and conducting an online survey of the extent, awareness and perceptions of dissemination bias in qualitative research. Results: We have defined dissemination bias in qualitative research as a systematic distortion of the phenomenon of interest due to selective dissemination of studies or individual study findings. Dissemination bias is important for qualitative evidence syntheses as the selective dissemination of qualitative studies and/or study findings may distort our understanding of the phenomena that these syntheses aim to explore and thereby undermine our confidence in these findings. Dissemination bias has been extensively examined in the context of randomised controlled trials and systematic reviews of such studies. The effects of potential dissemination bias are formally considered, as publication bias, within the GRADE approach. However, the issue has received almost no attention in the context of qualitative research. Because of very limited understanding of dissemination bias and its potential impact on review findings in the context of qualitative evidence syntheses, this component is currently not included in the GRADE-CERQual approach. Conclusions: Further research is needed to establish the extent and impacts of dissemination bias in qualitative research and the extent to which dissemination bias needs to be taken into account when we assess how much confidence we have in findings from qualitative evidence syntheses.WHONorad (Norwegian Agency for Development Cooperation)Research Council of NorwayCochrane Methods Innovation FundSouth African Medical Research Counci

The Iranian Study of Opium and Cancer (IROPICAN): Rationale, design, and initial findings

Background: The International Agency for Research on Cancer (IARC) recently classified opium use as a Group 1 carcinogen. However, much remains to be studied on the relation between opium and cancer. We designed the Iranian Opium and Cancer (IROPICAN) study to further investigate the association of opium use and cancers of the head and neck, bladder, lung, and colon and rectum. In this paper, we describe the rationale, design, and some initial results of the IROPICAN Study. Methods: The IROPICAN is a multi-center case-control study conducted in 10 provinces of Iran. The cases were all histologically confirmed and the controls were selected from hospital visitors who were free of cancer, were not family members or friends of the cancer patients, and were visiting the hospital for reasons other than their own ailment. The questionnaires included detailed questions on opium use (including age at initiation, duration, frequency, typical amount, and route), and potential confounders, such as tobacco use (e.g., cigarettes, nass and water-pipe), and dietary factors. Biological samples, including blood and saliva, were also collected. Results: The validation and pilot phases showed reasonably good validity, with sensitivities of 70% and 69% for the cases and controls, respectively, in reporting opium use. The results also showed excellent reliability, with intra-class correlation coefficients of 0.96 for ever opium use and 0.88 (95% CI: 0.80, 0.92) for regular opium use. In the main phase, we recruited 3299 cancer cases (99% response rate) and 3477 hospital visitor controls (89% response rate). The proportion of ever-use of opium was 40% among cases and 18% among controls. Conclusion: The IROPICAN study will serve as a major resource in studies addressing the effect of opium on risk of cancers of the head and neck, bladder, lung, and colon and rectum

Comparison of the Protective Effects of Melatonin and Silymarin Against Gentamicin-Induced Nephrotoxicity in Rats

This study compared the possible protective effects of silymarin and melatonin against gentamicin (GEN)-induced nephrotoxicity in rats. Rats were allocated to 6 groups: Group I, control group; Groups II and III, administered with silymarin or melatonin; Group IV, injected with GEN; and Groups V and VI, administered with silymarin or melatonin, and then injected with GEN. Compared with the rats in the control group, all rats injected with GEN significantly presented elevated levels of serum creatinine and urea that was accompanied by an increase in relative kidney weight, increase in renal reactive oxygen species (ROS) and malondialdehyde (MDA) levels, and reduction in renal glutathione (GSH) level and superoxide dismutase (SOD) activity. Silymarin and melatonin pretreatment significantly lowered the elevated serum urea and creatinine concentration, kidney weight, and renal ROS and MDA levels. In addition, silymarin and melatonin significantly enhanced renal GSH level and SOD activity. This study indicates that silymarin and melatonin can attenuate renal injury in rats treated with GEN possibly by reducing the ROS level. © 2015, © The Author(s) 2015