Accuracy plot for ImageJ analysis of the test card.

<p>Mis-categorized results are shown as empty circles or squares, correctly categorized results as filled circles or squares. All metrics are expressed as μg I/L.</p

Green design of a paper test card for urinary iodine analysis

<div><p>When young children do not receive adequate amounts of the micronutrient iodine in their diet, their growth and cognitive development can be impaired. Nearly every country in the world has programs in place to track iodine intake and provide supplemental iodine if needed, usually in the form of fortified salt. The iodine nutrition status of a population can be tracked by monitoring iodine levels in urine samples to see if the median value falls in the range of 100–300 micrograms of iodine per liter of urine (μg I/L), which indicates adequate or more than adequate iodine nutrition. Many low and middle-income countries (LMIC) do not have a laboratory capable of carrying out this challenging assay, so samples must be sent out for assay in external labs, which is expensive and time-consuming. In most LMIC, population iodine surveys are carried out every 5–10 years, which limits the utility of the data for program monitoring and evaluation. To solve this problem, we developed a field-friendly paper test card that uses the Sandell-Kolthoff reaction to measure urinary iodine levels. A blind internal validation study showed that 93% of samples (n = 60) of iodide in an artificial urine matrix were categorized correctly by visual analysis as deficient, adequate, or excessive for levels set forth by the World Health Organization. Quantitative measurements based on computer image analysis had an error of 40 ± 20 μg I/L (n = 35 for samples in the calibration range) and these results categorized 88% of the samples (n = 60) correctly. We employed lifecycle analysis principles to address the known toxicity of arsenic, which is an obligatory reagent in the Sandell-Kolthoff reaction. Disposal of the cards in a landfill (their most likely destination after use) could let arsenic leach into groundwater; toxicity characteristic leaching procedure (TCLP) tests showed that the level of arsenic leached from the cards was 28.78 ppm, which is above the United States Environmental Protection Agency’s limit of 5 parts per million for solid waste. We integrated a remediation module into the card. This module contains oxone, to oxidize As(III) to As(V) oxyacids, and the iron oxide goethite. TCLP testing showed that the leachable amount of arsenic was reduced by at least 97.6%—from 28.8 ppm to lower than 0.7 ± 0.7 ppm (n = 20). This upstream intervention rendered the test card suitable for landfilling while retaining its functionality to perform a critical public health evaluation.</p></div

Toxicity characteristic leaching procedure results for test cards with various amounts of goethite.

<p>At least 0.6 g goethite must be used to mitigate the leachate to acceptable arsenic levels. For the 0.9 g level, n = 20 and for all others n = 3. LOD = 0.028 ppm As. All error bars are shown, but some are too small to see on this scale.</p

The test card response to various levels of iodide at 3 minutes.

<p>The blank standard appears blue while the 100 μg I/L standard looks purple, and the 300 μg I/L standard is red. Each unknown was applied to three circles in a row; the concentration of iodide in the sample solution is shown below the row. The samples are visually categorized to contain < 100, 100–299, or ≥ 300 μg I/L.</p

Layout of the test card.

<p>A. Assay Module. The 0, 100, and 300 μg I/L internal iodide standards in the top row are used to determine the concentrations of the samples in the bottom rows. B. Remediation Module. The rectangular area is loaded with reagents to bind arsenic so it cannot leach into groundwater. After the assay is complete, the remediation module is folded on top of the assay module to render the test card non-toxic. Fiducial marks and color standards are printed on the card to facilitate automated image analysis.</p

MOESM1 of Yeast interfering RNA larvicides targeting neural genes induce high rates of Anopheles larval mortality

Additional file 1. Lack of siRNA larvicide target site conservation in non‐target organisms. Summary of Blast search results

MOESM2 of Yeast interfering RNA larvicides targeting neural genes induce high rates of Anopheles larval mortality

Additional file 2. A lack of Sac1.1 and otk.16 yeast interfering larvicide activity in A. aegypti larvae. Graph depicting results from larvicide trials that demonstrated a lack of larvicidal activity for yeast interfering RNA larvicides Sac1.1 and otk.16 in A. aegypti larvae