Data from: Likelihood Ratio and Score Tests to Test the Non-inferiority (or Equivalence) of the Odds Ratio in a Crossover Study with Binary Outcomes

We consider the non-inferiority (or equivalence) test of the odds ratio (OR) in a crossover study with binary outcomes to evaluate the treatment effects of two drugs. To solve this problem, Lui and Chang (2011) proposed both an asymptotic method and a conditional method based on a random effects logit model. Kenward and Jones (1987) proposed a likelihood ratio test (LRT_M) based on a log linear model. These existing methods are all subject to model misspecification. In this paper, we propose a likelihood ratio test (LRT) and a score test that are independent of model specification. Monte Carlo simulation studies show that, in scenarios considered in this paper, both the LRT and the score test have higher power than the asymptotic and conditional methods for the non-inferiority test; the LRT, score and asymptotic methods have similar power and they all have higher power than the conditional method for the equivalence test. When data can be well described by a log linear model, the LRT_M has the highest power among all the five methods (LRT_M, LRT, score, asymptotic and conditional) for both non-inferiority and equivalence tests. However, in scenarios for which a log linear model does not describe the data well, the LRT_M has the lowest power for the non-inferiority test and has inflated type I error rates for the equivalence test. We provide an example from a clinical trial that illustrates our methods

Direct Water Splitting Through Vibrating Piezoelectric Microfibers in Water

We propose a mechanism, a piezoelectrochemical effect for the direct conversion of mechanical energy to chemical energy. This phenomenon is further applied for generating hydrogen and oxygen via direct water decomposition by means of as-synthesized piezoelectric ZnO microfibers and BaTiO₃ microdendrites. Fibers and dendrites are vibrated with ultrasonic waves leading to a strain-induced electric charge development on their surface. With sufficient electric potential, strained piezoelectric fibers (and dendrites) in water triggered the redox reaction of water to produce hydrogen and oxygen gases. ZnO fibers under ultrasonic vibrations showed a stoichiometric ratio of H₂/O₂ (2:1) initial gas production from pure water. This study provides a simple and cost-effective technology for direct water splitting that may generate hydrogen fuels by scavenging energy wastes such as noise or stray vibrations from the environment. This new discovery may have potential implications in solving the challenging energy and environmental issues that we are facing today and in the future

Integrated Smartphone-App-Chip System for On-Site Parts-Per-Billion-Level Colorimetric Quantitation of Aflatoxins

We demonstrate herein an integrated, smartphone-app-chip (SPAC) system for on-site quantitation of food toxins, as demonstrated with aflatoxin B1 (AFB1), at parts-per-billion (ppb) level in food products. The detection is based on an indirect competitive immunoassay fabricated on a transparent plastic chip with the assistance of a microfluidic channel plate. A 3D-printed optical accessory attached to a smartphone is adapted to align the assay chip and to provide uniform illumination for imaging, with which high-quality images of the assay chip are captured by the smartphone camera and directly processed using a custom-developed Android app. The performance of this smartphone-based detection system was tested using both spiked and moldy corn samples; consistent results with conventional enzyme-linked immunosorbent assay (ELISA) kits were obtained. The achieved detection limit (3 ± 1 ppb, equivalent to μg/kg) and dynamic response range (0.5–250 ppb) meet the requested testing standards set by authorities in China and North America. We envision that the integrated SPAC system promises to be a simple and accurate method of food toxin quantitation, bringing much benefit for rapid on-site screening

Blu-ray Technology-Based Quantitative Assays for Cardiac Markers: From Disc Activation to Multiplex Detection

Acute myocardial infarction (AMI) is the leading cause of mortality and morbidity globally. To reduce the number of mortalities, reliable and rapid point-of-care (POC) diagnosis of AMI is extremely critical. We herein present a Blu-ray technology-based assay platform for multiplex cardiac biomarker detection; not only off-the-shelf Blu-ray discs (BDs) were adapted as substrates to prepare standard immunoassays and DNA aptamer/antibody hybrid assays for the three key cardiac marker proteins (myoglobin, troponin I, and C-creative protein) but also an unmodified optical drive was directly employed to read the assay results digitally. In particular, we have shown that all three cardiac markers can be quantitated in their respective physiological ranges of interest, and the detection limits achieved are comparable with conventional enzyme-linked immunosorbent assay (ELISA) kits. The Blu-ray assay platform was further validated by measuring real-world samples and establishing a linear correlation with the simultaneously obtained ELISA data. Without the need to modify either the hardware (Blu-ray discs and optical drives) or the software driver, this assay-on-a-BD technique promises to be a low-cost user-friendly quantitative tool for on-site chemical analysis and POC medical diagnosis

Detection and Quantitation of Heavy Metal Ions on Bona Fide DVDs Using DNA Molecular Beacon Probes

A sensitive and cost-effective method for the simultaneous quantitation of trace amounts of Hg²⁺ and Pb²⁺ in real-world samples has been developed using DNA molecular beacon probes bound to bona fide digital video discs (DVDs). With specially designed T-rich or G-rich loop sequences, the detection is based on the strong T-Hg²⁺-T coordination chemistry of Hg²⁺ and the formation of G-quadruplexes induced by Pb²⁺, respectively. In particular, the presence of metal cations leads to hairpin opening and exposure of the terminal biotin moiety for binding nanogold–streptavidin conjugates. The recognition signal was subsequently enhanced by gold nanoparticle-promoted silver deposition, which leads to quantifiable digital signals upon reading with a standard computer drive. This method exhibits a wide response range and low detection limits for both Hg²⁺ and Pb²⁺. In addition, the quantitative determination of heavy metals in food products (e.g., rice samples) has been demonstrated and the method compares favorably with other optical sensors developed recently

Ultrasonic-Assisted Synthesis of Surface-Clean TiB₂ Nanoparticles and Their Improved Dispersion and Capture in Al-Matrix Nanocomposites

Metal-matrix nanocomposites (MMNCs) have great potential for a wide range of applications. To provide high performance, effective nanoparticle (NP) dispersion in the liquid and NP capture within the metal grains during solidification is essential. In this work, we present the novel synthesis and structural characterization of surface-clean titanium diboride (TiB₂) NPs with an average particle size of 20 nm, by ultrasonic-assisted reduction of fluorotitanate and fluoroboride salts in molten aluminum. The high-intensity ultrasonic field restricts NP growth. Using a master nanocomposite approach, the as-prepared TiB₂ NPs are effectively incorporated into A206 alloys during solidification processing because of their clean surface, showing partial capture and significant grain refinement

Modification of different types of filter paper and standard printing paper.

<p>The pore sizes and flow rates [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0151439#pone.0151439.ref028" target="_blank">28</a>] are listed for comparison.</p

SEM images of the silanized filter paper after immersion in diesel (a, b) and gasoline (c, d) for 12 hours.

<p>SEM images of the silanized filter paper after immersion in diesel (a, b) and gasoline (c, d) for 12 hours.</p

Separation of an oil/water mixture.

<p>The water layer has been dyed blue to allow for easier visualization. The mixture is poured onto the silanized filter paper fitted on a glass funnel. As the colorless oil layer permeates the filter paper (b-d), the water layer (blue) remains. The water layer is finally collected into a new vial and showed beside the oil sample (e).</p

Separation efficiency of the modified filter paper for (a) different ratios of oil/water mixtures and (b) different preparation methods of the oil (diesel)/ water mixture.

<p>(1) Water and diesel oil were mixed without resting; (2) water and diesel oil were mixed, vibrated for 5 min, without resting; (3) water and diesel oil were mixed, vibrated for 5 min and rested for 2 days; (4) water and diesel oil were ultrasonically mixed for 5 min and rested for 2 days.</p