Light deflection by photonic crystals

When propagating through periodically structured media, i. e. photonic crystals, optical waves will be modulated with the periodicity. As a result, the dispersion of waves will no longer behave as in a free space, and so called frequency band structures appear. Under certain conditions, waves may be prohibited from propagation in certain or all directions, corresponding to partial and complete bandgaps respectively. Here we report a new fascinating phenomenon associated with the partial gaps, that is, deflection of optical waves. This phenomenon will render novel applications in manipulating light flows.Comment: 3 pages, 4 figure

Online Information on Dysmenorrhea: An Evaluation of Readability, Credibility, Quality, and Usability

Aims and objectives To evaluate online information on dysmenorrhoea, including readability, credibility, quality and usability. Background Menstrual pain impacts 45%–95% of women of reproductive age globally and is the leading cause of school and work absences among women. Women often seek online information on dysmenorrhoea; however, little is known about the information quality. Design This was a descriptive study to evaluate online information on dysmenorrhoea. Methods We imitated search strategies of the general public. Specifically, we employed the three most popular search engines worldwide—Google, Yahoo and Bing—and used lay search terms, “period pain” and “menstrual cramps.” We screened 60 web pages. Following removal of duplicates and irrelevant web pages, 25 met the eligibility criteria. Two team members independently evaluated the included web pages using standardised tools. Readability was evaluated with the Flesch–Kincaid Reading Ease and Flesch–Kincaid Grade formulas; credibility, quality and usability were evaluated with established tools. We followed the STROBE checklist for reporting this study. Results For readability, the mean Flesch–Kincaid level was 10th grade. For credibility, 8% of web pages referenced scientific literature and 28% stated the author's name and qualifications. For quality, no web page employed user‐driven content production; 8% of web pages referenced evidence‐based guidelines, 32% of web pages had accurate content, and 4% of web pages recommended shared decision‐making. Most web pages were interactive and included nontextual information. Some nontextual information was inaccurate. Conclusion Online information on dysmenorrhoea has generally low readability, mixed credibility and variable quality. Relevance to clinical practice Strategies to improve health information on dysmenorrhoea include avoiding complex terms, incorporating visual aids, presenting evidence‐based information and developing a decision aid to support shared decision‐making. Healthcare providers should be aware of the problematic health information that individuals are exposed to and provide education about how to navigate online health information

A Novel Structure for Double Negative NIMs towards UV Spectrum with High FOM

A novel ring structure is proposed for double negative NIMs at visible light spectrum with high FOM (e.g. about 11 at a wavelength of 583 nm) and low loss. Besides the effective medium theory, an equivalent circuit model is also given to explain physically why our novel structure can give double negative behavior with low loss. Adapted from the original ring structure, two other types of structures, namely, disk and nanowire structures, are also given to further push double negative NIMs toward ultraviolet (UV) spectrum

Polyethylene glycol combined with lactulose has better efficacy than polyethylene glycol alone in bowel preparation before colonoscopy: A meta-analysis

Background: The accuracy of diagnosis and the safety of treatment in colonoscopy depends largely on the quality of bowel cleansing. This study aimed to compare the efficacy and adverse reactions of Polyethylene Glycol (PEG) combined with lactulose with that of PEG alone in bowel preparation before colonoscopy. Methods: The authors searched a number of databases including EMBASE, MEDLINE, Cochrane Library, and China Academic Journals Full-text Database. The authors screened according to literature inclusion and exclusion criteria, assessed the quality of the included literature, and extracted the data. The meta-analysis of included literature used RevMan 5.3 and Stata 14.0 software. Results: A total of 18 studies, including 2274 patients, were enrolled. The meta-analysis showed that PEG combined with lactulose had a better efficacy (OR = 3.87, 95% CI 3.07‒4.87, p = 0.000, and I2 = 36.2% in the efficiency group; WMD = 0.86, 95% CI 0.69‒1.03, p = 0.032 and I2 = 0% in the BBPS score group) in bowel preparation for patients with or without constipation. Moreover, PEG combined with lactulose had fewer adverse reactions, including abdominal pain (OR = 1.42, 95% CI 0.94‒2.14, p = 0.094), nausea (OR = 1.60, 95% CI 1.13‒2.28, p = 0.009) and vomiting (OR = 1.77, 95% CI 1.14‒2.74, p = 0.011), than PEG alone. No significant reduction in the incidence of abdominal distention was observed. Conclusion: PEG combined with lactulose may be a better choice for bowel preparation before colonoscopy compared with PEG alone

Excitation of guided waves in layered structures with negative refraction

We study the electromagnetic beam reflection from layered structures that include the so-called double-negative materials, also called left-handed metamaterials. We predict that such structures can demonstrate a giant lateral Goos-Hanchen shift of the scattered beam accompanied by splitting of the reflected and transmitted beams due to the resonant excitation of surface waves at the interfaces between the conventional and double-negative materials as well as due to excitation of leaky modes in the layered structures. The beam shift can be either positive or negative, depending on the type of the guided waves excited by the incoming beam. We also perform finite-difference time-domain simulations and confirm the major effects predicted analytically.Comment: 13 pqages, 10 figures. Also available at http://www.opticsexpress.org/abstract.cfm?URI=OPEX-13-2-48

Loss compensation in Metamaterials through embedding of active transistor based negative differential resistance circuits

This paper presents an all-electronic approach for loss compensation in metamaterials. This is achieved by embedding active-transistors based negative differential resistance (NDR) circuits in each unit cell of the metamaterial lattice. NDR circuits provide tunable loss compensation over a broad frequency range limited only by the maximum operating frequency of transistors that is reaching terahertz values in newer semiconductor processes. Design, simulation and experimental results of metamaterials composed of split ring resonators (SRR) with and without loss compensation circuits are presented

Sub-wavelength imaging with a left-handed material flat lens

We study numerically, by means of the pseudospectral time-domain method, the unique features of imaging by a flat lens made of a left-handed metamaterial that possesses the property of negative refraction. We confirm the earlier finding that a left-handed flat lens can provide near-perfect imaging of a point source and a pair of point sources with clear evidence of the sub-wavelength resolution. We illustrate the limitation of the resolution in the time-integrated image due to the presence of surface waves.Comment: 4 pages, RevTeX, 6 figures; added references and some discussio

Rural Redemption: A Model to Help Understand the Perspectives of Rural Americans Related to Vaccine Science

Rural communities are vital to the foundation of American agriculture and are currently disproportionately affected by health and environmental challenges that will require broad scientific solutions. Cooperative Extension professionals and agricultural communicators are increasingly tasked with communicating about the science surrounding these topics and need effective tools for determining strategic communication tactics to influence personal behaviors. The purpose of this study was to understand the role of community-based social marketing (CBSM) concepts and trust in science on rural Americans’ intentions and attitudes toward the COVID-19 vaccine. A hypothesized model was developed that included concepts of CBSM, trust in science, intentions, and attitudes all related to the COVID-19 vaccine. Results showed that CBSM principles had significant explanatory power for predicting intentions to receive the COVID-19 vaccine. CBSM and trust in science were also significant predictors of rural Americans attitudes toward the COVID-19 vaccine. Implications for this study reveal a need for future research and practice related to communicating about science and vaccines to rural Americans while building community-based principles for increasing trust and advancing perceptions of science. Future research should determine the impact of CBSM and trust in science on the end-state behavior of receiving the vaccine. Additionally, Extension professionals and agricultural communicators should prioritize CBSM concepts when developing programming and messages related to health behaviors

Functional Profiling of Transcription Factor Genes in Neurospora crassa.

Regulation of gene expression by DNA-binding transcription factors is essential for proper control of growth and development in all organisms. In this study, we annotate and characterize growth and developmental phenotypes for transcription factor genes in the model filamentous fungus Neurospora crassa We identified 312 transcription factor genes, corresponding to 3.2% of the protein coding genes in the genome. The largest class was the fungal-specific Zn2Cys6 (C6) binuclear cluster, with 135 members, followed by the highly conserved C2H2 zinc finger group, with 61 genes. Viable knockout mutants were produced for 273 genes, and complete growth and developmental phenotypic data are available for 242 strains, with 64% possessing at least one defect. The most prominent defect observed was in growth of basal hyphae (43% of mutants analyzed), followed by asexual sporulation (38%), and the various stages of sexual development (19%). Two growth or developmental defects were observed for 21% of the mutants, while 8% were defective in all three major phenotypes tested. Analysis of available mRNA expression data for a time course of sexual development revealed mutants with sexual phenotypes that correlate with transcription factor transcript abundance in wild type. Inspection of this data also implicated cryptic roles in sexual development for several cotranscribed transcription factor genes that do not produce a phenotype when mutated