Invasive aquatic species introductions cause tremendous environmental and economic damage. Conservation and management efforts will benefit from rapid, inexpensive, and accurate on-site methods to detect harmful aquatic species to prevent their introduction and spread. Here, two technologies, environmental DNA (eDNA) sampling and Light Transmission Spectroscopy (LTS), were combined to address this need. Specifically, eDNA filtering and extraction methods were used to isolate DNA from: (1) lake water samples that were seeded with a microscopic fragment of five high-risk invasive species and (2) untreated samples from lakes infested with the invasive zebra mussel, Dreissena polymorpha, followed by polymerase chain reaction (PCR) amplification. LTS was then used to detect size shifts resulting from hybridization of PCR products with nanobeads covered with species-specific oligonucleotide probes. The results demonstrate that coupling eDNA sampling with LTS species detection can provide a sensitive and real-time solution for screening real-world water samples for invasive species.

Background An induced-pain paradigm has been used in back-healthy people to understand risk factors for developing low back pain during prolonged standing. Objectives The purposes of this study were to (1) compare baseline lumbar lordosis in back-healthy participants who do (Pain Developers) and do not (Non-Pain Developers) develop low back pain during 2 hours of standing, and (2) examine the relationship between lumbar lordosis and low back pain intensity. Design Cross-Sectional Method First, participants stood while positions of markers placed on the lumbar vertebrae were recorded using a motion capture system. Following collection of marker positions, participants stood for 2 hours while performing light work tasks. At baseline and every 15 minutes during standing, participants rated their low back pain intensity on a visual analog scale. Lumbar lordosis was calculated using marker positions collected prior to the 2 hour standing period. Lumbar lordosis was compared between pain developers and non-pain developers. In pain developers, the relationship between lumbar lordosis and maximum pain was examined. Results/findings There were 24 (42%) pain developers and 33 (58%) non-pain developers. Lumbar lordosis was significantly larger in pain developers compared to non pain developers (Mean difference=4.4°; 95% Confidence Interval=0.9° to 7.8°, Cohen’s d=0.7). The correlation coefficient between lumbar lordosis and maximum pain was 0.46 (P=0.02). Conclusion The results suggest that standing in more lumbar lordosis may be a risk factor for low back pain development during prolonged periods of standing. Identifying risk factors for low back pain development can inform preventative and early intervention strategies.

Laser transmission spectroscopy (LTS) is a quantitative and rapid in vitro technique for measuring the size, shape, and number of nanoparticles in suspension. Here we report on the application of LTS as a novel detection method for species-specific DNA where the presence of one invasive species was differentiated from a closely related invasive sister species. The method employs carboxylated polystyrene nanoparticles functionalized with short DNA fragments that are complimentary to a specific target DNA sequence. In solution, the DNA strands containing targets bind to the tags resulting in a sizable increase in the nanoparticle diameter, which is rapidly and quantitatively measured using LTS. DNA strands that do not contain the target sequence do not bind and produce no size change of the carboxylated beads. The results show that LTS has the potential to become a quantitative and rapid DNA detection method suitable for many real-world applications.

We describe the implementation of precision laser transmission spectroscopy for sizing and counting nanoparticles in suspension. Our apparatus incorporates a tunable laser and balanced optical system that measures light transmission over a wide (210-2300 nm) wavelength range with high precision and sensitivity. Spectral inversion is employed to determine both the particle size distribution and absolute particle density. In this paper we discuss results for particles with sizes (diameters) in the range from 5 to 3000 nm. For polystyrene particles 404 to 1025 nm in size, uncertainties of ±0.5% in size and ±4% in density were obtained. For polystyrene particles from 46 to 3000 nm in size, the dynamic range of the system spans densities from ~10(3)/ml to ~10(10)/ml (5 × 10(-8) to 0.5 vol. %), implying a sensitivity 5 orders of magnitude higher than dynamic light scattering.

Background Limitation in function is a primary reason people with low back pain seek medical treatment. Specific lumbar movement patterns, repeated throughout the day, have been proposed to contribute to the development and course of low back pain. Varying the demands of a functional activity test may provide some insight into whether people display consistent lumbar movement patterns during functional activities. Our purpose was to examine the consistency of the lumbar movement pattern during variations of a functional activity test in people with low back pain and back-healthy people. Methods 16 back-healthy adults and 32 people with low back pain participated. Low back pain participants were classified based on the level of self-reported functional limitations. Participants performed 5 different conditions of a functional activity test. Lumbar excursion in the early phase of movement was examined. The association between functional limitations and early phase lumbar excursion for each test condition was examined. Findings People with low back pain and high levels of functional limitation demonstrated a consistent pattern of greater early phase lumbar excursion across test conditions (p<.05). For each test condition, the amount of early phase lumbar excursion was associated with functional limitation (r=0.28–0.62) Interpretation Our research provides preliminary evidence that people with low back pain adopt consistent movement patterns during the performance of functional activities. Our findings indicate that the lumbar spine consistently moves more readily into its available range in people with low back pain and high levels of functional limitation. How the lumbar spine moves during a functional activity may contribute to functional limitations.