Publications by authors named "David Love"

84 Publications

Rapid adaptation to crisis events: Insights from the bait crisis in the Maine lobster fishery.

Ambio 2021 Sep 14. Epub 2021 Sep 14.

Northeast Fisheries Science Center, National Marine Fisheries Service, National Oceanographic and Atmospheric Administration, Woods Hole, MA, 02543, USA.

Climate change, overfishing, and other anthropogenic drivers are forcing marine resource users and decision makers to adapt-often rapidly. In this article we introduce the concept of pathways to rapid adaptation to crisis events to bring attention to the double-edged role that institutions play in simultaneously enabling and constraining swift responses to emerging crises. To develop this concept, we draw on empirical evidence from a case study of the iconic Maine lobster (Homarus americanus) industry. In the Gulf of Maine, the availability of Atlantic herring (Clupea harengus) stock, a key source of bait in the Maine lobster industry, declined sharply. We investigate the patterns of bait use in the fishery over an 18-year period (2002-2019) and how the lobster industry was able to abruptly adapt to the decline of locally-sourced herring in 2019 that came to be called the bait crisis. We found that adaptation strategies to the crisis were diverse, largely uncoordinated, and imperfectly aligned, but ultimately led to a system-level shift towards a more diverse and globalized bait supply. This shift was enabled by existing institutions and hastened an evolution in the bait system that was already underway, as opposed to leading to system transformation. We suggest that further attention to raceways may be useful in understanding how and, in particular, why marine resource users and coastal communities adapt in particular ways in the face of shocks and crises.
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http://dx.doi.org/10.1007/s13280-021-01617-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8439535PMC
September 2021

Emerging COVID-19 impacts, responses, and lessons for building resilience in the seafood system.

Glob Food Sec 2021 Mar 6;28:100494. Epub 2021 Feb 6.

College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, 201306, China.

The COVID-19 pandemic and subsequent lockdowns are creating health and economic crises that threaten food and nutrition security. The seafood sector provides important sources of nutrition and employment, especially in low-income countries, and is highly globalized allowing shocks to propagate. We studied COVID-19-related disruptions, impacts, and responses to the seafood sector from January through May 2020, using a food system resilience 'action cycle' framework as a guide. We find that some supply chains, market segments, companies, small-scale actors and civil society have shown initial signs of greater resilience than others. COVID-19 has also highlighted the vulnerability of certain groups working in- or dependent on the seafood sector. We discuss early coping and adaptive responses combined with lessons from past shocks that could be considered when building resilience in the sector. We end with strategic research needs to support learning from COVID-19 impacts and responses.
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http://dx.doi.org/10.1016/j.gfs.2021.100494DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8417121PMC
March 2021

Dural Tear Does not Increase the Rate of Venous Thromboembolic Disease in Patients Undergoing Elective Lumbar Decompression with Instrumented Fusion.

World Neurosurg 2021 Jul 29. Epub 2021 Jul 29.

Department of Orthopaedic Surgery, University of Maryland Medical Center, Baltimore, Maryland, USA. Electronic address:

Objective: Evaluate if dural tears (DTs) are an indirect risk factor for venous thromboembolic disease through increased recumbency in patients undergoing elective lumbar decompression and instrumented fusion.

Methods: This was a retrospective cohort study of consecutive patients undergoing elective lumbar decompression and instrumented fusion at a single institution between 2016 and 2019. Patients were divided into cohorts: those who sustained a dural tear and those who did not. The cohorts were compared using Student's t-test or Wilcoxon Rank Sum for continuous variables and Fisher exact or chi-squared test for nominal variables.

Results: Six-hundred and eleven patients met inclusion criteria, among which 144 patients (23.6%) sustained a DT. The DT cohort tended to be older (63.6 vs. 60.6 years, P = 0.0052) and have more comorbidities (Charlson Comorbidity Index 2.75 vs. 2.35, P = 0.0056). There was no significant difference in the rate of symptomatic deep vein thrombosis (2.1% vs. 2.6%, P = 1.0) or pulmonary embolus (1.4% vs. 1.50%, P = 1.0). Intraoperatively, DT was associated with increased blood loss (754 mL vs. 512 mL, P < 0.0001), operative time (224 vs. 195 minutes, P < 0.0001), and rate of transfusion (19.4% vs. 9.4%, P = 0.0018). Postoperatively, DT was associated with increased time to ambulation (2.6 vs. 1.4 days, P < 0.0001), length of stay (5.8 vs. 4.0 days, P < 0.0001), and rate of discharge to rehab (38.9 vs. 25.3%, P = 0.0021).

Conclusions: While DTs during elective lumbar decompression and instrumentation led to later ambulation and longer hospital stays, the increased recumbency did not significantly increase the rate of symptomatic venous thromboembolic disease.
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http://dx.doi.org/10.1016/j.wneu.2021.07.107DOI Listing
July 2021

The roles of conduit redundancy and connectivity in xylem hydraulic functions.

New Phytol 2021 08 2;231(3):996-1007. Epub 2021 Jun 2.

Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA.

Wood anatomical traits shape a xylem segment's hydraulic efficiency and resistance to embolism spread due to declining water potential. It has been known for decades that variations in conduit connectivity play a role in altering xylem hydraulics. However, evaluating the precise effect of conduit connectivity has been elusive. The objective here is to establish an analytical linkage between conduit connectivity and grouping and tissue-scale hydraulics. It is hypothesized that an increase in conduit connectivity brings improved resistance to embolism spread due to increased hydraulic pathway redundancy. However, an increase in conduit connectivity could also reduce resistance due to increased speed of embolism spread with respect to pressure. We elaborate on this trade-off using graph theory, percolation theory and computational modeling of xylem. The results are validated using anatomical measurements of Acer branch xylem. Considering only species with vessels, increases in connectivity improve resistance to embolism spread without negatively affecting hydraulic conductivity. The often measured grouping index fails to capture the totality of the effect of conduit connectivity on xylem hydraulics. Variations in xylem network characteristics, such as conduit connectivity, might explain why hypothesized trends among woody species, such as the 'safety-efficiency' trade-off hypothesis, are weaker than expected.
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http://dx.doi.org/10.1111/nph.17429DOI Listing
August 2021

Nutrition and origin of US chain restaurant seafood.

Am J Clin Nutr 2021 06;113(6):1546-1555

Center for a Livable Future, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.

Background: Seafood has a nutritional profile that can be beneficial to human health, which gives it a role to play in healthy diets. In addition, because its production and harvesting can have fewer environmental impacts than some forms of animal protein, it can contribute to sustainable diets. However, the positive health and environmental outcomes are not guaranteed-they depend on how seafood is prepared and served and whether it is sourced from sustainable fisheries and aquaculture industries.

Objectives: We examined the availability and nutritional attributes of seafood meals at chain restaurants in the United States. We assessed nutritional attributes by store type and geography. We also assessed menu labeling for species, production methods, and origin.

Methods: The study population was 159 chain restaurants with 100,948 branch locations in the United States. Data were harvested from online restaurant menus, and the nutritional profile of seafood meals was calculated.

Results: The average seafood menu item provides up to 49-61% of the total daily limit of saturated fat, 65% of the total daily limit of sodium, and 58-71% of total daily protein requirement for adult men and women. Restaurant chains located in the Deep South and Ohio River Valley, and casual dining chains nationally, carry seafood meals with more total calories and saturated fat per 100 g than other regions or chain types. Most menu items did not list origin or production methods, which is information that would help consumers make informed decisions.

Conclusions: The added ingredients and cooking methods used at chain restaurants can attenuate the health benefits of seafood. We recommend reformulating menus to reduce portion sizes, total calories, added fat, and sodium content per meal and to improve consumer-facing information about origin and production methods.
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http://dx.doi.org/10.1093/ajcn/nqaa437DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8168351PMC
June 2021

Self-reported work activities, eye, nose, and throat symptoms, and respiratory health outcomes among an industrial hog operation worker cohort, North Carolina, USA.

Am J Ind Med 2021 05 22;64(5):403-413. Epub 2021 Feb 22.

Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA.

Introduction: Respiratory disease among industrial hog operation (IHO) workers is well documented; however, it remains unclear whether specific work activities are more harmful and if personal protective equipment (PPE), as used by workers, can reduce adverse health outcomes.

Methods: IHO workers (n = 103) completed baseline and up to eight bi-weekly study visits. Workers reported typical (baseline) and transient (bi-weekly) work activities, PPE use, and physical health symptoms. Baseline and longitudinal associations were assessed using generalized logistic and fixed-effects logistic regression models, respectively.

Results: At baseline, reports of ever versus never drawing pig blood, applying pesticides, and increasing years worked at any IHO were positively associated with reports of eye, nose, and/or throat irritation. Over time, transient exposures, associated with dustiness in barns, cleaning of barns, and pig contact were associated with increased odds of sneezing, headache, and eye or nose irritation, particularly in the highest categories of exposure. When PPE was used, workers had lower odds of symptoms interfering with sleep (odds ratio [OR]: 0.1; 95% confidence interval [CI]: 0.01-0.8), and eye or nose irritation (OR: 0.1; 95% CI: 0.02-0.9). Similarly, when they washed their hands eight times or more per shift (median frequency) versus less frequently, the odds of any respiratory symptom were reduced (OR: 0.3; 95% CI: 0.1-0.8).

Conclusions: In this healthy volunteer worker population, increasingly unfavorable IHO activities were associated with self-reported eye, nose, throat, and respiratory health symptoms. Strong protective associations were seen between PPE use and handwashing and the odds of symptoms, warranting further investigation.
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http://dx.doi.org/10.1002/ajim.23236DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8046736PMC
May 2021

Electrochemiluminescence and Photoluminescence of Carbon Quantum Dots Controlled by Aggregation-Induced Emission, Aggregation-Caused Quenching, and Interfacial Reactions.

Langmuir 2020 Dec 18;36(47):14432-14442. Epub 2020 Nov 18.

Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada.

Carbon quantum dots (CQDs) show promise in optoelectronics as a light emitter due to simple synthesis, biocompatibility and strong tunable light emissions. However, CQDs commonly suffer from aggregation caused quenching (ACQ), inhibiting the full potential of these light emitters. Studies into different ideal light emitters have shown enhancements when converting common ACQ effects to aggregation induced emission (AIE) effects. We report CQD synthesis using citric acid and high/low thiourea concentrations, or sample 2/1. These two CQDs exhibited AIE and ACQ PL effects, respectively. CQD characterizations and photoluminescence interrogations of CQD films and solutions revealed that these unique emission mechanisms likely arose from different S incorporations into the CQDs. Furthermore, it was discovered that sample 2 emitted electrochemiluminescence (ECL) more intensely than sample 1 in a homogenous solution with SO as a coreactant, due to aggregation and interactions of CQD species in solution. Very interestingly, sample 1's CQD film|SO system achieved an ECL efficiency of 26% and emitted roughly 26 times more efficiently than sample 2 in the same conditions. Predominant interfacial reactions and surface state emission produced intense white light with a correlated color temperature of 2000 K. Spooling ECL spectroscopy was utilized to investigate emission mechanisms. Sample 2's CQD film|TPrA system had four times higher ECL intensity than that of sample 1, most likely due to π-cation interactions leading to a strong CQD stability, thereby, enhancing ECL. It is anticipated that ECL enhancement of CQD films or solutions by means of AIE will lead to wide CQD optoelectronic applications.
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http://dx.doi.org/10.1021/acs.langmuir.0c02886DOI Listing
December 2020

Single-molecule DNA sequencing of widely varying GC-content using nucleotide release, capture and detection in microdroplets.

Nucleic Acids Res 2020 12;48(22):e132

Base 4 Innovation Ltd, Broers Building, JJ Thomson Avenue, Cambridge CB3 0FA, UK.

Despite remarkable progress in DNA sequencing technologies there remains a trade-off between short-read platforms, having limited ability to sequence homopolymers, repeated motifs or long-range structural variation, and long-read platforms, which tend to have lower accuracy and/or throughput. Moreover, current methods do not allow direct readout of epigenetic modifications from a single read. With the aim of addressing these limitations, we have developed an optical electrowetting sequencing platform that uses step-wise nucleotide triphosphate (dNTP) release, capture and detection in microdroplets from single DNA molecules. Each microdroplet serves as a reaction vessel that identifies an individual dNTP based on a robust fluorescence signal, with the detection chemistry extended to enable detection of 5-methylcytosine. Our platform uses small reagent volumes and inexpensive equipment, paving the way to cost-effective single-molecule DNA sequencing, capable of handling widely varying GC-bias, and demonstrating direct detection of epigenetic modifications.
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http://dx.doi.org/10.1093/nar/gkaa987DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7736801PMC
December 2020

Efficient White Electrochemiluminescent Emission From Carbon Quantum Dot Films.

Front Chem 2020 29;8:580022. Epub 2020 Sep 29.

Department of Chemistry, The University of Western Ontario, London, ON, Canada.

Carbon quantum dots (CQDs) were manufactured from citric acid and urea in a gram-scale synthesis with a controlled size range between 1. 5 and 23.8 nm. The size control was realized by varying volume of the precursor solution in a hydrothermal synthesis method. The prepared CQDs were investigated using electrochemiluminescence (ECL) spectroscopy at interfaces of their electrode films and electrolyte solution containing coreactants rather than conventional optoelectronic tests, providing an in-depth analysis of light-emission mechanisms of the so-called half-cells. ECL from the CQD films with TPrA and KSO as coreactants provided information on the stability of the CQD radicals in the films. It was discovered that CQD has a powerful electron donating nature to sulfate radical to generate ECL at a relative efficiency of 96% to the Ru(bpy)Cl/KSO coreactant system, indicating a strong performance in light emitting applications. The smaller the CQD particle sizes, the higher the ECL efficiency of the film interface, most likely due to the increased presence of surface states per mass of CQDs. Spooling ECL spectroscopy of the system revealed a potential-dependent light emission starting from a deep red color to blue-shifted intensity maximum, cool bright white emission with a correlated color temperature of 3,200 K. This color temperature is appropriate for most indoor lighting applications. The above ECL results provide information on the performance of CQD light emitters in films, permitting preliminary screening for light emitting candidates in optoelectronic applications. This screening has revealed CQD films as a powerful and cost-effective light emitting layer toward lighting devices for indoor applications.
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http://dx.doi.org/10.3389/fchem.2020.580022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7552666PMC
September 2020

Global and peak local specific absorption rate control on parallel transmit systems using k-means SAR compression model.

Magn Reson Med 2021 02 18;85(2):1093-1103. Epub 2020 Aug 18.

School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA.

Purpose: To improve the specific absorption rate (SAR) compression model capability in parallel transmission (pTx) MRI systems.

Methods: A k-means clustering method is proposed to group voxels with similar SAR behaviors in the scanned object, providing a controlled upper-bounded estimation of peak local SARs. This k-means compression model and the conventional virtual observation point (VOP) model were tested in a pTx MRI framework. The pTx pulse design with different SAR controlling schemes was simulated using a numerical human head model and an eight-channel 7T coil array. Multiple criteria (including RF power, global and peak local SARs, and excitation accuracy) were compared for the performance testing.

Results: The k-means compression model generated a narrower overestimation bound, leading to a more accurate local SAR estimation. Among different pTx pulse design approaches, the k-means compression model showed the best trade-off between the SAR and excitation accuracy.

Conclusions: The developed SAR compression model is advantageous for pTx framework given the narrower overestimation bound and control over the compression ratio. Results also illustrate that a moderate increase of maximum RF power can be useful for reducing the maximum local SAR deposition.
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http://dx.doi.org/10.1002/mrm.28456DOI Listing
February 2021

Electrogenerated Chemiluminescence and Electroluminescence of N-Doped Graphene Quantum Dots Fabricated from an Electrochemical Exfoliation Process in Nitrogen-Containing Electrolytes.

Chemistry 2020 Dec 6;26(68):15892-15900. Epub 2020 Oct 6.

Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, ON, N6A 5B7, Canada.

Artificial lighting sources are one of the most important technological developments for our modern lives; the search for cost-effective and efficient luminophores is therefore crucial to a sustainable future. Graphene quantum dots (GQDs) are carbon-based nanomaterials that exhibit exceptional optical and electronic properties, making them a prime candidate for a luminophore in a light-emitting device. Nitrogen-doped GQDs fabricated from a facile top-down electrochemical exfoliation process with a nitrogen-containing electrolyte in this report showed strong photoluminescent emission at 450 nm, and electrogenerated chemiluminescence at 660 nm in the presence of benzoyl peroxide as a coreactant. When introduced into solid-state light-emitting electrochemical cells, for the first time, the GQDs displayed a broad white emission centered at 610 nm, corresponding to Commision Internationale de l'eclairage (CIE) colour coordinates of (0.38, 0.36).
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http://dx.doi.org/10.1002/chem.202003395DOI Listing
December 2020

Food Sources and Expenditures for Seafood in the United States.

Nutrients 2020 Jun 17;12(6). Epub 2020 Jun 17.

Johns Hopkins Center for a Livable Future, Johns Hopkins University, Baltimore, MD 21202, USA.

The aim of this study was to explore United States (U.S.) seafood consumption patterns, food sourcing, expenditures, and geography of consumption. We analyzed seafood intake and food sourcing using the National Health and Nutrition Examination Survey (NHANES) cycles 2007-2008 to 2015-2016 for US adults ≥19 years old ( = 26,743 total respondents; = 4957 respondents consumed seafood in the past 24 h). Seafood expenditures were extrapolated by combining NHANES with three other public datasets. U.S. adults consumed 63% of seafood (by weight) at home. The top sources of seafood (by weight) were food retail (56%), restaurants (31%), and caught by the respondent or someone they know (5%). Sixty-five percent of consumer expenditures for seafood were at restaurants and other "away from home" sources while 35% were at retail and other "at home" sources. Slightly less than half of overall U.S. food expenditures are "away from home," which is much lower than for seafood, suggesting that consumers have very different spending habits for seafood than for an aggregate of all foods.
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http://dx.doi.org/10.3390/nu12061810DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7353403PMC
June 2020

Visualizing Magnetic Structure in 3D Nanoscale Ni-Fe Gyroid Networks.

Nano Lett 2020 May 10;20(5):3642-3650. Epub 2020 Apr 10.

Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.

Arrays of interacting 2D nanomagnets display unprecedented electromagnetic properties via collective effects, demonstrated in artificial spin ices and magnonic crystals. Progress toward 3D magnetic metamaterials is hampered by two challenges: fabricating 3D structures near intrinsic magnetic length scales (sub-100 nm) and visualizing their magnetic configurations. Here, we fabricate and measure nanoscale magnetic gyroids, periodic chiral networks comprising nanowire-like struts forming three-connected vertices. Via block copolymer templating, we produce NiFe single-gyroid and double-gyroid (an inversion pair of single-gyroids) nanostructures with a 42 nm unit cell and 11 nm diameter struts, comparable to the exchange length in Ni-Fe. We visualize their magnetization distributions via off-axis electron holography with nanometer spatial resolution and interpret the patterns using finite-element micromagnetic simulations. Our results suggest an intricate, frustrated remanent state which is ferromagnetic but without a unique equilibrium configuration, opening new possibilities for collective phenomena in magnetism, including 3D magnonic crystals and unconventional computing.
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http://dx.doi.org/10.1021/acs.nanolett.0c00578DOI Listing
May 2020

DERMATITIS AND RHINOSINUITIS CAUSED BY SPECIES IN A CHINESE GORAL ().

J Zoo Wildl Med 2020 Jan;50(4):1008-1011

The Wilds, Cumberland, OH 43732, USA.

Curvularia spp. are globally distributed saprophytic fungi, classified in the literature as dematiaceous, or darkly pigmented fungi. These fungi have been increasingly recognized as causing cutaneous, ocular, respiratory, and central nervous system infections in humans, but have been infrequently documented as pathogens in the veterinary literature. A 5-yr-old male Chinese goral () presented with bilateral fungal dermatitis of the pinnae, and subsequent pyogranulomatous rhinosinusitis. Clinical signs included epistaxis, mucosanguineous nasal discharge, and dyspnea. Sequential histologic examinations of cutaneous and nasal lesions revealed pyogranulomatous inflammation with extracellular and phagocytized nonpigmented yeasts. Fungal culture and polymerase chain reaction identified sp. The absence of pigmentation in tissue in this case suggests that pigmentation may not be a consistent histologic finding for this fungus, emphasizing the importance of molecular identification to prevent misidentification. Despite intensive interventions in this goral, the disease progressed, and was ultimately fatal.
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http://dx.doi.org/10.1638/2018-0013DOI Listing
January 2020

TUBERCULOSIS CAUSED BY IN A GREATER ONE-HORNED RHINOCEROS (): FIRST REPORT IN THE WESTERN HEMISPHERE.

J Zoo Wildl Med 2020 Jan;50(4):1000-1004

The Wilds, Cumberland, OH 43732, USA.

, a newly identified member of the complex, has been isolated predominantly from hoofstock in eastern Africa and the Arabian Peninsula, and sporadically in cattle (), rhesus monkeys (), humans, and a greater one-horned rhinoceros () in South Asia. In rhinoceros, tuberculosis typically presents as a chronic progressive respiratory disease. The report describes the postmortem diagnosis of tuberculosis caused by in a greater one-horned rhinoceros with hind limb paresis due to neural granulomatosis. Serologic assays for detection of antibodies to complex proteins before culture results allowed for appropriate herd management protocols to be initiated. genus-specific polymerase chain reaction assays with direct sequencing allowed timely confirmation of the serologic results. This is the first isolation of in the western hemisphere, showing the need for mycobacterial testing of rhinoceros before international shipments and the urgency for validated antemortem complex screening assays in rhinoceros species.
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http://dx.doi.org/10.1638/2018-0084DOI Listing
January 2020

Multiple-Input Multiple-Output (MIMO) MRI: Combining Parallel Excitation and Parallel Reception for Enhanced Imaging.

IEEE Trans Comput Imaging 2019 Dec 13;5(4):596-605. Epub 2019 Mar 13.

School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907.

Magnetic resonance imaging (MRI) plays a critical role in visualizing the structure and functions of the human body. In order to accelerate imaging time and improve image quality, radio-frequency (RF) coil receive arrays are commonly employed to acquire the magnetic resonance (MR) signal. Similarly, multiple transmit coils have been shown to accelerate and refine RF excitation. In this work, we investigate the optimization of total imaging time and image accuracy when considering both the transmit and receive coil arrays; we term this strategy multiple-input multiple-output (MIMO) MRI. Our RF pulse design method is modeled by minimizing the excitation errors while simultaneously maximizing the signal-to-noise ratio (SNR) of the reconstructed MR image. It further allows a key tradeoff between the two optimizers. Additionally, multiple acceleration factors, varying numbers of receive coils used, maximum excitation error tolerance, and different excitation patterns are simulated and analyzed in this model. For a given excitation pattern, our method is shown to improve the SNR by 18-130% under certain acceleration schemes, as compared to conventional parallel transmission methods, while simultaneously controlling the excitation error within a desired scope (NRMSE ≤ 0.12).
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http://dx.doi.org/10.1109/tci.2019.2904882DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6929686PMC
December 2019

Performance of cold chains and modeled growth of Vibrio parahaemolyticus for farmed oysters distributed in the United States and internationally.

Int J Food Microbiol 2020 Jan 25;313:108378. Epub 2019 Oct 25.

Pacific Shellfish Institute, Olympia, WA, United States of America.

Vibrio bacteria can accumulate in molluscan shellfish and cause human diseases. The United States (U.S.) has implemented Vibrio Control Plans to mitigate risks associated with these bacteria, which include time and temperature requirements for post-harvest processing and maintaining an unbroken cold chain. In this study, we tracked the performance of cold chains for U.S. farmed oysters distributed nationally and internationally using temperature sensors. Boxes and bags of oysters (n = 125) were shipped from farms in Washington State and the Chesapeake Bay to 143 unique businesses in 20 U.S. states, Washington D.C., and Hong Kong, China. Eighty-one percent of the temperature sensors were returned with usable data. The average product temperature among all participants was 4.4 ± 2.7 °C (40 ± 5 °F), which is 5.6 °C (10 °F) cooler than the 10 °C (50 °F) guidance criterium established by the U.S. government. There were spikes in temperature in some shipments: 18% of shipments (16/91) experienced oyster temperatures above 10 °C for one hour or more, and the median time spent out of temperature control was 2.5 h. We modeled V. parahaemolyticus abundance using temperature sensor data and 75% (68/91) of shipments had a net decrease in V. parahaemolyticus abundance in the cold chain. There are opportunities for improvements in cold chain performance in the shellfish industry and related businesses. In the discussion we provide recommendations for oyster producers related to product cooling, for businesses that handle shellfish, and for government and industry groups to develop guidance for shipping by air, among other issues.
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http://dx.doi.org/10.1016/j.ijfoodmicro.2019.108378DOI Listing
January 2020

Occupational Safety and Health in U.S. Aquaculture: A Review.

J Agromedicine 2019 10 21;24(4):405-423. Epub 2019 Jul 21.

South Dakota Department of Game, Fish and Parks, McNenny State Fish Hatchery, Spearfish, SD, USA.

: Aquaculture encompasses a variety of species in both freshwater and marine settings and can combine elements of agriculture and fishing, two recognized hazardous occupations. Efforts are underway to expand the aquaculture sector in the United States (U.S.), and should be informed by occupational safety and health (OSH) research. The objectives of this review paper are to: i) describe the U.S. aquaculture sector, ii) summarize statistics, peer-reviewed studies, and reports focused on U.S. aquaculture OSH, and iii) describe the policy landscape specific to U.S. aquaculture OSH.: Literature searches employed databases and Internet search engines to identify relevant peer-reviewed articles, reports, and other resources. Due to the expected U.S. expansion of marine aquaculture and paucity of peer-reviewed U.S.-based OSH literature in this sector, additional searches for international research on marine aquaculture were conducted.: The U.S. Bureau of Labor Statistics estimated high rates of illness and injury among U.S. aquaculture workers in 2014 and 2015. Peer-reviewed literature on aquaculture OSH identified numerous physical, chemical, and biological OSH risks depending on production methods and settings. Significant policy gaps exist regarding U.S. aquaculture OSH surveillance, reporting, and regulation.: This review identifies a critical need for research, surveillance, and best practices information, specific to the major types of aquaculture in the U.S., to augment and inform worker safety and health efforts in this expanding sector.
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http://dx.doi.org/10.1080/1059924X.2019.1639574DOI Listing
October 2019

Single-molecule detection of deoxyribonucleoside triphosphates in microdroplets.

Nucleic Acids Res 2019 09;47(17):e101

Base4 Innovation Ltd, Broers Building, 21 JJ Thomson Avenue, Cambridge CB3 0FA, UK.

A new approach to single-molecule DNA sequencing in which dNTPs, released by pyrophosphorolysis from the strand to be sequenced, are captured in microdroplets and read directly could have substantial advantages over current sequence-by-synthesis methods; however, there is no existing method sensitive enough to detect a single nucleotide in a microdroplet. We have developed a method for dNTP detection based on an enzymatic two-stage reaction which produces a robust fluorescent signal that is easy to detect and process. By taking advantage of the inherent specificity of DNA polymerases and ligases, coupled with volume restriction in microdroplets, this method allows us to simultaneously detect the presence of and distinguish between, the four natural dNTPs at the single-molecule level, with negligible cross-talk.
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http://dx.doi.org/10.1093/nar/gkz611DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6753480PMC
September 2019

HOST FACTORS AND TESTING MODALITY AGREEMENT ASSOCIATED WITH INFECTION IN A FREE-RANGING SNAKE POPULATION IN SOUTHEAST OHIO, USA.

J Zoo Wildl Med 2019 Jun 13;50(2):405-413. Epub 2019 Jun 13.

The Wilds, Cumberland, OH 43732, USA.

Snake fungal disease (SFD) is an emerging mycotic disease caused by and has been demonstrated to impact snake populations of conservation concern in the United States negatively. Although has been shown to affect diverse taxa and to have a broad distribution, host factors associated with infected individuals and optimal testing protocols are not yet well characterized. The purpose of this study was to evaluate host factors and agreement across testing modalities associated with infection in a free-ranging snake population in southeast Ohio. Wild-caught snakes were swabbed and biopsied to test for via quantitative polymerase chain reaction (qPCR), culture, and histopathology. The host parameters assessed were species, sex, snout-vent length, body weight, month captured, and presence of gross skin lesions. A total of 8/30 individuals across three species-Black Racers (), Grey Ratsnakes (), and Eastern Gartersnakes ()-tested positive via at least one testing modality for infection. There were no associations between sex, snout-vent length, or weight and infection status. A higher proportion of individuals with gross lesions tested positive for than those without gross lesions, and most individuals that tested positive were caught in April or May. A low level of agreement was observed across testing modalities. Swab qPCR identified the most -positive individuals, and fungal culture identified the fewest at 0 individuals. Although there are limitations associated with a sample size of 30, these findings support the potential of this pathogen to infect individuals broadly across species and size, highlighting the relevance of this disease for snake conservation efforts. They also suggest that although little agreement was observed across test modalities, the concurrent use of multiple modalities is a more sensitive method for characterizing prevalence and distribution of .
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http://dx.doi.org/10.1638/2018-0143DOI Listing
June 2019

The stomatal response to rising CO2 concentration and drought is predicted by a hydraulic trait-based optimization model.

Tree Physiol 2019 08;39(8):1416-1427

School of Biological Sciences, University of Utah, Salt Lake City, UT, USA.

Modeling stomatal control is critical for predicting forest responses to the changing environment and hence the global water and carbon cycles. A trait-based stomatal control model that optimizes carbon gain while avoiding hydraulic risk has been shown to perform well in response to drought. However, the model's performance against changes in atmospheric CO2, which is rising rapidly due to human emissions, has yet to be evaluated. The present study tested the gain-risk model's ability to predict the stomatal response to CO2 concentration with potted water birch (Betula occidentalis Hook.) saplings in a growth chamber. The model's performance in predicting stomatal response to changes in atmospheric relative humidity and soil moisture was also assessed. The gain-risk model predicted the photosynthetic assimilation, transpiration rate and leaf xylem pressure under different CO2 concentrations, having a mean absolute percentage error (MAPE) of 25%. The model also predicted the responses to relative humidity and soil drought with a MAPE of 21.9% and 41.9%, respectively. Overall, the gain-risk model had an MAPE of 26.8% compared with the 37.5% MAPE obtained by a standard empirical model of stomatal conductance. Importantly, unlike empirical models, the optimization model relies on measurable physiological traits as inputs and performs well in predicting responses to novel environmental conditions without empirical corrections. Incorporating the optimization model in larger scale models has the potential for improving the simulation of water and carbon cycles.
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http://dx.doi.org/10.1093/treephys/tpz038DOI Listing
August 2019

'Pressure fatigue': the influence of sap pressure cycles on cavitation vulnerability in Acer negundo.

Tree Physiol 2019 05;39(5):740-746

School of Biological Sciences, University of Utah, 257 S 1400E, Salt Lake City, UT, USA.

Vulnerability-to-cavitation curves (VCs) can vary within a tree crown in relation to position or branch age. We tested the hypothesis that VC variation can arise from differential susceptibility to the number of diurnal sap pressure cycles experienced. We designed a method to distinguish between effects of cycling vs exposure time to negative pressure, and tested the influence of sap pressure cycles on cavitation vulnerability between upper and lower branches in Acer negundo L. trees using static and flow centrifuge, and air-injection methods. Branches from the upper crown had greater hydraulic conductivity and were more resistant to cavitation than branches from the lower crown. Upper branches also showed little change after exposure to 10 or 20 pressure cycles between -0.5 MPa and -2.0 MPa. Lower branches, however, showed a marked increase in vulnerability to cavitation after pressure-cycling. This result suggests that 'cavitation fatigue' can occur without the actual induction (and reversal) of cavitation as documented previously, but simply from the cycling of pressures in the sub-cavitation range. This 'pressure fatigue' may explain age-related shifts in VCs that could eventually induce dieback in suppressed branches or trees. Pressure fatigue may help explain developmental variation in hydraulic capacity of branches within individuals.
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http://dx.doi.org/10.1093/treephys/tpy148DOI Listing
May 2019

Performance of Cold Chains for Chesapeake Bay Farmed Oysters and Modeled Growth of Vibrio parahaemolyticus.

J Food Prot 2019 01;82(1):168-178

6 Pacific Shellfish Institute, 120 State Avenue N.E. #1056, Olympia, Washington 98501, USA.

Temperature-controlled supply chains (cold chains) require an unbroken chain of refrigeration to maintain product quality and safety. This study investigated cold chains for farmed oysters raised in the Chesapeake Bay, one of the largest shellfish-growing regions in the United States, and sold live to the half-shell market in surrounding states. Temperature sensors were used in boxes of oysters from February to September 2017, which generated 5,250 h of temperature data. Thirty-nine businesses participated in the temperature sensor study, and 26 of those businesses participated in interviews to further understand how cold chains function. Internal oyster temperatures were measured above 50°F (10°C) for over 1 h in 19% (7 of 36) of shipments, which is a temperature that exceeds National Shellfish Sanitation Program criteria. The highest internal oyster temperature recorded in any shipment was 54.5°F (12.5°C). Some parts of the cold chain had difficulty maintaining storage temperatures below 45°F (7.2°C) in warmer months when Vibrio control plans were in effect. We modeled the effects of temperature on Vibrio parahaemolyticus. The model predicted moderate bacterial growth before oysters were under temperature control, but cold chains prevented further bacterial growth and provided a moderate drop-off in V. parahaemolyticus abundance.
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http://dx.doi.org/10.4315/0362-028X.JFP-18-044DOI Listing
January 2019

Face Mask Use and Persistence of Livestock-associated Nasal Carriage among Industrial Hog Operation Workers and Household Contacts, USA.

Environ Health Perspect 2018 12;126(12):127005

Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.

Background: Industrial hog operation (IHO) workers may persistently carry antibiotic-resistant, livestock-associated in their nasal cavities. It is unclear whether IHO work activities can alter IHO workers' and their household members' exposure to these bacteria.

Objective: Our objective was to investigate the relationship of IHO work activities with persistence of antibiotic-resistant, livestock-associated S. aureus nasal carriage among IHO workers and their household members.

Methods: At biweekly intervals over 4 months, IHO workers and their household members completed questionnaires and provided nasal swabs that were assessed for , multidrug-resistant (MDRSA), and livestock-associated markers (tetracycline resistance, absence, type). We examined the association between transient and habitual IHO work activities and nasal carriage outcomes.

Results: One hundred one IHO workers and 79 household members completed 1,456 study visits. Face mask use (each 25% increase) was associated with reduced odds of nasal carriage of MDRSA (odds ratio [OR]: 0.65 [95% confidence interval (CI): 0.46, 0.92], tetracycline-resistant [OR = 0.74 (95% CI: 0.56, 0.97)], and clonal complex (CC) 398/CC9 [OR = 0.77 (95% CI: 0.60, 0.99)]. IHO workers who ever (vs. never) gave pigs injections had higher odds of these outcomes. Among household members, living with an IHO worker who consistently ([Formula: see text] of the time) versus sometimes or never used a face mask was associated with reduced odds of carrying -negative , tetracycline-resistant , and CC398/CC9 (OR range: 0.12-0.20, all [Formula: see text]), and consistent IHO worker coveralls use was associated with reduced odds of household member MDRSA carriage only. Living with an IHO worker who habitually had contact with [Formula: see text] hogs (vs. [Formula: see text]) was associated with higher odds of household member livestock-associated carriage.

Conclusions: Consistent face mask use was associated with reduced exposure to antibiotic-resistant, livestock-associated among IHO workers and their household members. https://doi.org/10.1289/EHP3453.
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http://dx.doi.org/10.1289/EHP3453DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6371678PMC
December 2018

Antimicrobial resistance is a shared global problem.

Authors:
David M Love

Vet Rec 2018 11;183(20):626

Schlusselmattuweg 15, CH-3917 Kippel, Switzerland.

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http://dx.doi.org/10.1136/vr.k4912DOI Listing
November 2018

Passive noise datasets at regolith sites.

Data Brief 2018 Oct 31;20:735-747. Epub 2018 Aug 31.

Department of State Development, Government of South Australia, 101 Grenfell Street, Adelaide, SA 5000, Australia.

The data presented in this article contain datasets of passive noise measurements at regolith sites in Adelaide, South Australia. The data were acquired using three component (3C) LE-3Dlite Lennartz seismometers with an eigenfrequency of 1 Hz. The data were acquired at eight sites across Adelaide׳s regolith in a hexagonal array layout. Four tests, each with a duration of 30 min, were conducted at different times. The ambient noise data can be used for both horizontal to vertical spectral ratio (HVSR) analysis and array analyses, which are essential to obtain the site fundamental frequency and the ellipticity of the fundamental mode Rayleigh waves at the measured site. The array analyses are useful to obtain the dispersion curves, which are needed to estimate the shear wave velocity profile.
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http://dx.doi.org/10.1016/j.dib.2018.08.055DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6129695PMC
October 2018

Microplastics in Seafood and the Implications for Human Health.

Curr Environ Health Rep 2018 09;5(3):375-386

Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.

Purpose Of Review: We describe evidence regarding human exposure to microplastics via seafood and discuss potential health effects.

Recent Findings: Shellfish and other animals consumed whole pose particular concern for human exposure. If there is toxicity, it is likely dependent on dose, polymer type, size, surface chemistry, and hydrophobicity. Human activity has led to microplastic contamination throughout the marine environment. As a result of widespread contamination, microplastics are ingested by many species of wildlife including fish and shellfish. Because microplastics are associated with chemicals from manufacturing and that sorb from the surrounding environment, there is concern regarding physical and chemical toxicity. Evidence regarding microplastic toxicity and epidemiology is emerging. We characterize current knowledge and highlight gaps. We also recommend mitigation and adaptation strategies targeting the life cycle of microplastics and recommend future research to assess impacts of microplastics on humans. Addressing these research gaps is a critical priority due to the nutritional importance of seafood consumption.
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http://dx.doi.org/10.1007/s40572-018-0206-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6132564PMC
September 2018

A stomatal control model based on optimization of carbon gain versus hydraulic risk predicts aspen sapling responses to drought.

New Phytol 2018 11 12;220(3):836-850. Epub 2018 Jul 12.

Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA.

Empirical models of plant drought responses rely on parameters that are difficult to specify a priori. We test a trait- and process-based model to predict environmental responses from an optimization of carbon gain vs hydraulic risk. We applied four drought treatments to aspen (Populus tremuloides) saplings in a research garden. First we tested the optimization algorithm by using predawn xylem pressure as an input. We then tested the full model which calculates root-zone water budget and xylem pressure hourly throughout the growing season. The optimization algorithm performed well when run from measured predawn pressures. The per cent mean absolute error (MAE) averaged 27.7% for midday xylem pressure, transpiration, net assimilation, leaf temperature, sapflow, diffusive conductance and soil-canopy hydraulic conductance. Average MAE was 31.2% for the same observations when the full model was run from irrigation and rain data. Saplings that died were projected to exceed 85% loss in soil-canopy hydraulic conductance, whereas surviving plants never reached this threshold. The model fit was equivalent to that of an empirical model, but with the advantage that all inputs are specific traits. Prediction is empowered because knowing these traits allows knowing the response to climatic stress.
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http://dx.doi.org/10.1111/nph.15333DOI Listing
November 2018

Footprints preserve terminal Pleistocene hunt? Human-sloth interactions in North America.

Sci Adv 2018 04 25;4(4):eaar7621. Epub 2018 Apr 25.

Institute for Studies in Landscapes and Human Evolution, Bournemouth University, Poole BH12 5BB, UK.

Predator-prey interactions revealed by vertebrate trace fossils are extremely rare. We present footprint evidence from White Sands National Monument in New Mexico for the association of sloth and human trackways. Geologically, the sloth and human trackways were made contemporaneously, and the sloth trackways show evidence of evasion and defensive behavior when associated with human tracks. Behavioral inferences from these trackways indicate prey selection and suggest that humans were harassing, stalking, and/or hunting the now-extinct giant ground sloth in the terminal Pleistocene.
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http://dx.doi.org/10.1126/sciadv.aar7621DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5916513PMC
April 2018

In situ embolism induction reveals vessel refilling in a natural aspen stand.

Tree Physiol 2018 07;38(7):1006-1015

Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, USA.

Little is known about the ability of trees to recover hydraulic conductance (k) within a growing season by regrowth or refilling of embolized conduits. Recovery of k lost to drought or other causes would prevent chronic reductions in gas exchange and productivity. To test recovery ability we conducted a 2-year experiment (2014-15) on a cohort of aspen ramets (Populus tremuloides, Michx.). Whole-tree k was measured from mid-June through September from sapflow (Q) and pre-dawn and mid-day xylem pressure. We induced embolism in the treatment group with high air pressure delivered by a split pressure chamber sealed around the main trunk. Successful treatments reduced k and Q by 50% or more without causing rapid desiccation. The majority of trees recovered following treatment, rising to control levels of k and Q between 12 and 17 days. Failure to recover was correlated with drier climate conditions. The growing-season recovery of k was attributed to refilling of embolized vessels, based on the absence of diameter growth. Pre-dawn xylem pressures during recovery were similar to the threshold needed to passively collapse emboli. Successful recovery during the 2-year study was consistent with no reduction in cumulative Q or canopy area in treatment vs controls. However, non-recovering trees in 2014 exhibited lower basal area growth at the start of the 2015 growing season, suggesting a linkage between recovery ability and productivity. This study provides evidence for the potential of trees to recover xylem function by refilling during the growing season.
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http://dx.doi.org/10.1093/treephys/tpy007DOI Listing
July 2018
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