Abstract Background The success of radiofrequency (RF) ablation is limited by the inability to assess thermal tissue damage achieved during or immediately after the procedure. The goal of this ...proof-of-principle study was to investigate whether diffuse reflectance (DR) spectroscopy during and after RF ablation of liver tumours could aid in detecting complete tissue ablation. Material and methods DR spectra were acquired in vivo in eight patients undergoing RF ablation for unresectable colorectal liver metastases, using a disposable spectroscopy needle. Intraoperative ultrasound imaging was used for accurate positioning of the RF electrode and the spectroscopy needle. Spectral changes were quantified and correlated to tissue histopathology and follow-up CT imaging. Results For the lesions in which ablation was monitored by DR spectroscopy (N = 8), median tumour size was 1.6 cm (range 0.8–3.3 cm). We found an excellent correlation (97–99%) between thermal damage suggested by spectral changes and histology. DR spectroscopy allowed discrimination between non-ablated and ablated tissue, regardless whether the needle was placed in tumour tissue or in surrounding liver tissue. Additional measurements performed continuously during ablation confirmed that the magnitude of spectral change correlates with the histochemical degree of thermal damage. Conclusions Diffuse reflectance spectroscopy allows accurate quantification of thermal tissue damage during and after RF ablation. Real-time feedback by DR spectroscopy could improve the accuracy and quality of the RF procedures by lowering incomplete ablation rates.
Paired vegetable/soil samples from New York City and Buffalo, NY, gardens were analyzed for lead (Pb), cadmium (Cd) and barium (Ba). Vegetable aluminum (Al) was measured to assess soil adherence. ...Soil and vegetable metal concentrations did not correlate; vegetable concentrations varied by crop type. Pb was below health-based guidance values (EU standards) in virtually all fruits. 47% of root crops and 9% of leafy greens exceeded guidance values; over half the vegetables exceeded the 95th percentile of market-basket concentrations for Pb. Vegetable Pb correlated with Al; soil particle adherence/incorporation was more important than Pb uptake via roots. Cd was similar to market-basket concentrations and below guidance values in nearly all samples. Vegetable Ba was much higher than Pb or Cd, although soil Ba was lower than soil Pb. The poor relationship between vegetable and soil metal concentrations is attributable to particulate contamination of vegetables and soil characteristics that influence phytoavailability.
•We analyzed metals (Pb, Ba and Cd) in paired urban garden vegetable/soil samples.•Soil and vegetable metal concentrations did not correlate.•Metals levels were highest in leafy/herb and lowest in fruiting vegetables.•Some vegetable Pb exceeded market-basket levels and guidance values (EU standards).•Soil particle adherence increases metal concentrations in vegetables.
Metal concentrations in garden vegetables are impacted by soil particle contamination and soil characteristics that influence phytoavailability.
Urban community gardeners employ a range of best practices that limit crop contamination by toxicants like lead (Pb). While Pb root uptake is generally low, the relative significance of various Pb ...deposition processes and the effectiveness of best practices in reducing these processes have not been sufficiently characterized. This study compared leafy lettuce (Lactuca sativa) grown in high Pb (1150 mg/kg) and low Pb (90 mg/kg) soils, under three different soil cover conditions: 1) bare soil, 2) mulch cover to limit splash, and 3) mulch cover under hoophouses to limit splash and air deposition, in a New York City (NYC) community garden and a rural site in Ithaca, New York (NY). The lettuces were further compared to greenhouse (Ithaca) and supermarket (NYC) samples. Atmospheric deposition was monitored by passive trap collection through funnel samplers. Results show that in low Pb soils, splash and atmospheric deposition accounted for 84 and 78% of lettuce Pb in NYC and Ithaca, respectively. In high Pb soils, splash and atmospheric deposition accounted for 88 and 93% of Pb on lettuces, with splash being the dominant mechanism. Soil covers were shown to be effective at significantly (p < 0.05) reducing lettuce Pb contamination, and mulching is strongly recommended as a best practice.
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•Plants take up limited lead from roots but can be contaminated by surface processes.•Lead (Pb) uptake, splash, and atmospheric deposition were evaluated for lettuce.•Splash was found to be the dominant mechanism driving Pb contamination.•Use of mulch and hoophouses significantly reduced Pb concentrations on lettuce.•Management techniques like mulching are strongly recommended to limit Pb exposure.
Urban gardeners contribute to sustainable cities and often take great care to limit exposure to soil contaminants like lead (Pb). Although best management practices (BMPs) like mulching to reduce ...soil splash can limit crop contamination, they may not eliminate all contamination for leafy greens, which trap soil particles. How effective is washing at removing Pb contamination from leafy greens when using BMPs? Are certain washing techniques more effective than others? We present results from two experiments addressing these questions. We grew lettuce (Lactuca sativa L.) in homogenized high‐Pb (∼1,150 mg kg–1) and low‐Pb (∼90 mg kg–1) soils in Brooklyn, NY, and Ithaca, NY. Our results show that washing can remove 75–94% of Pb from lettuce, including that remaining after the use of contamination‐reducing BMPs. It was estimated that washing removed 97% of Pb deposited by splash, which is the dominant source of Pb, and removed 91% deposited by downward deposition. All washing techniques were effective at reducing Pb levels, with differences in effectiveness ranked as: commercial soak > vinegar soak > water soak (and water rinse not significantly different from vinegar or water soak). Washing crops grown in low‐Pb soils is also important. Without washing, lettuce grown in low‐Pb soil may still have Pb levels above the European Commission comparison value. We offer these empirical findings and recommendations in support of urban growers.
Core Ideas
Best management practices (BMPs) for limiting crop contamination need evaluation.
We assessed washing techniques in high‐ and low‐Pb soils, with other BMPs.
All washing techniques significantly reduced lettuce Pb concentrations.
An estimated 97% of Pb from soil splash and 91% from atmospheric deposition were washed off.
Washing crops grown even in low‐Pb soils is important in urban environments.
The potential for lead (Pb) and arsenic (As) transfer into vegetables was studied in an old orchard land contaminated with lead arsenate pesticides. Root (carrot), leafy (lettuce), and vegetable ...fruits (green bean, tomato) were grown on seven “miniplots” with soil concentrations ranging from near background to ≈800 and ≈200 mg kg
−1
of total Pb and As, respectively. Each miniplot was divided into sub-plots and amended with 0 % (control), 5 %, and 10 % (by weight) compost and cropped for 3 years. Edible portions of each vegetable were analyzed for total Pb and As to test the effect of organic matter on transfer of these toxic elements into the crop. Vegetable Pb and As concentrations were strongly correlated to soil total Pb and As, respectively, but not to soil organic matter content or compost addition level. For Pb vegetable concentrations, carrot ≥ lettuce > bean > tomato. For As, lettuce > carrot > bean > tomato. A complementary single-year study of lettuce, arugula, spinach, and collards revealed a beneficial effect of compost in reducing both Pb and As concentrations in leafy vegetables. Comparisons of all measured vegetable concentrations to international health-based standards indicate that tomatoes can be grown without exceeding standards even in substantially Pb- and As-contaminated soils, but carrots and leafy green vegetables may exceed standards when grown in soils with more than 100–200 mg kg
−1
Pb. Leafy green vegetables may also exceed health-based standards in gardens where soil As is elevated, with arugula having a particularly strong tendency to accumulate As.
Co-firing of secondary biomass fuels with coal in coal-fired pulverized fuel boilers is facing increased application in large-scale power production. Fundamental knowledge on the thermochemical ...behavior of biomass and waste fuels is still lacking, especially regarding the release of the fuel bound nitrogen. Characterization of chicken litter (CL), biomass mix (BM) and meat and bone meal (MBM) and an HV coal blend was performed using TG-FTIR analysis. Three heating rate profiles were applied (10, 30 and 100 deg C/min), with a final temperature of 900 deg C. NH3 was found to be the major gaseous N-product, while HCN and HNCO were also released in substantial amounts. Kinetic parameters for the pyrolysis of biomass fuels were obtained using a model based on parallel first-order reactions with a Gaussian distribution of activation energies. Input files for the coal FG-DVC (functional group-devolatilization, vaporization, cross-linking) and FG-BioMass pyrolysis models were prepared. The fit of model parameters to TG-FTIR product-evolution data was found to be generally good, but the model-predicted yields for some species did not fit experimental data at all heating rates equally well. This problem can be overcome by improvements in the FG-BioMass model. The results of this study can be used to have an improved input of initial pyrolysis in CFD modeling of co-fired boilers.
•The first SOFC-based poly-generation system with complete CO2 recovery is presented.•The oxy-combustion and H2O separation steps do not present technical limitations.•The photobioreactor has ...revealed as the most problematic component of the chain.•Micro-algae are really a fast growing biomass (weekly peak of 4.18W/m2).•The CO2 emissions from the system are 0 kgCO2/kWhel if a CO2 buffer is considered.
In the context of the paradigm of Carbon Recovery and Re-utilization (or CRR), this work investigates the role of electrochemical generators (such as high-temperature fuel cells) to perform CRR as a practical secondary effect.
In fact, the solid oxide fuel cell (SOFC) operating principle is inherently beneficial toward CO2 separation from the exhaust gas since the fuel is electrochemically oxidized resulting in no N2 mixing at the anode (fuel) electrode. An oxy-combustor downstream the fuel cell will complete the residual fuel (mostly H2 and CO) oxidation to yield a stream that contains only H2O and CO2. After water condensation and further drying, the captured CO2 is fed to a photobioreactor that can fix carbon into microalgae.
In this work, results of the first SOFC-based poly-generation system with complete CO2 recovery in the form of fast-growing biomass (micro-algae) are presented, as developed in the EU-funded project SOFCOM (GA 278798, www.sofcom.eu).
The overall plant layout is described, and results on the performance of the proof-of-concept plant units are provided.
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