Self-trapping of optical beams in photorefractive media

We study the possibility of self-trapping of an optical beam in a photorefractive medium under the combined influence of diffraction and self-scattering (two-wave mixing) of its spatial frequency components. We investigate the spectrum of solutions for the resulting photorefractive spatial solitons and discuss their unique properties. Design considerations and material requirements for experimental realization of these solitons, together with specific examples, are given

Western corn rootworm pyrethroid resistance confirmed by aerial application simulations of commercial insecticides

The western corn rootworm (Diabrotica virgifera virgifera LeConte) (WCR) is a major insect pest of corn (Zea mays L.) in the United States (US) and is highly adaptable to multiple management tactics. A low level of WCR field-evolved resistance to pyrethroid insecticides has been confirmed in the US western Corn Belt by laboratory dose-response bioassays. Further investigation has identified detoxification enzymes as a potential part of the WCR resistance mechanism, which could affect the performance of insecticides that are structurally related to pyrethroids, such as organophosphates. Thus, the responses of pyrethroid-resistant and -susceptible WCR populations to the commonly used pyrethroid bifenthrin and organophosphate dimethoate were compared in active ingredient bioassays. Results revealed a relatively low level of WCR resistance to both active ingredients. Therefore, a simulated aerial application bioassay technique was developed to evaluate how the estimated resistance levels would affect performance of registered rates of formulated products. The simulated aerial application technique confirmed pyrethroid resistance to formulated rates of bifenthrin whereas formulated dimethoate provided optimal control. Results suggest that the relationship between levels of resistance observed in dose-response bioassays and actual efficacy of formulated product needs to be further explored to understand the practical implications of resistance

Bifenthrin Baseline Susceptibility and Evaluation of Simulated Aerial Applications in \u3ci\u3eStriacosta albicosta\u3c/i\u3e (Lepidoptera: Noctuidae)

Striacosta albicosta (Smith) is a maize pest that has recently expanded its geographical range into the eastern United States and southeastern Canada. Aerial application of pyrethroids, such as bifenthrin, has been a major practice adopted to manage this pest. Reports of field failure of pyrethroids have increased since 2013. Striacosta albicosta populations were collected in 2016 and 2017 from maize fields in Nebraska, Kansas, and Canada and screened with bifenthrin active ingredient in larval contact dose-response bioassays. Resistance ratios estimated were generally low in 2016 (1.04- to 1.32-fold) with the highest LC50 in North Platte, NE (66.10 ng/cm2) and lowest in Scottsbluff, NE (50.10 ng/cm2). In 2017, O’Neill, NE showed the highest LC50 (100.66 ng/cm2) and Delhi, Canada exhibited the lowest (6.33 ng/cm2), resulting in a resistance ratio variation of 6.02- to 15.90-fold. Implications of bifenthrin resistance levels were further investigated by aerial application simulations. Experiments were conducted with a spray chamber where representative S. albicosta populations were exposed to labeled rates of a commercial bifenthrin formulation. Experiments resulted in 100% mortality for all populations, instars, insecticide rates, and carrier volumes, suggesting that levels of resistance estimated for bifenthrin active ingredient did not seem to impact the efficacy of the correspondent commercial product under controlled conditions. Results obtained from this research indicate that control failures reported in Nebraska could be associated with factors other than insecticide resistance, such as issues with the application technique, environmental conditions during and/or after application, or the insect’s natural behavior. Data generated will assist future S. albicosta resistance management programs

Particle drift potential of mesotrione and rimsulfuron plus thifensulfuron-methyl tank mixture in a low-speed wind tunnel

Particle drift happens during herbicide application when droplets travel outside the intended site. Different nozzles produce various range of droplets, so they play a very important role in coverage and drift occasions. When nozzles produce small droplets, the potential for off-target movement is very high. Another important factor determining particle drift is the distance between crops. Wind velocity gives the energy to herbicide particles to move away from the target place. Therefore, a drift simulation of herbicide (mesotrione and rimsulfuron plus thifensulfuron-methyl mixture) was done in a wind tunnel, using different nozzles Extended Range (XR) and Turbo TeeJet Induction (TTI). The wind speed was set at 4.4 m/s, representing the least favourable conditions where applications are possible. In the wind tunnel, eight crops (cantaloupe, cotton, green bean, pumpkin, soybean, sunflower, wheat, and watermelon) were positioned at 4, 6, 9, and 12 m downwind distances from the nozzle, and drift was simulated. Following treatments, plants were returned to a greenhouse for 28 days, and biomass reduction was recorded. Artificial collectors (Mylar cards) and water sensitive cards were positioned alongside plants. According to obtained results, spraying with XR nozzle influences higher injuries than TTI nozzle. Tracer deposition was higher at all distances when XR nozzle was used. Accordingly, droplet numbers, covered area, Volume Median Diameter (VMD), and deposition were higher on water sensitive cards when spraying were done using XR nozzle. As a consequence, higher biomass reduction occurred using the XR nozzle. The most sensitive crops were cantaloupe, pumpkin and sunflower, while the most tolerant were soybean and wheat

Anisotropic super-attenuation of capillary waves on driven glass interfaces

Metrological AFM measurements are performed on the silica glass interfaces of photonic band-gap fibres and hollow capillaries. The freezing of attenuated out-of-equilibrium capillary waves during the drawing process is shown to result in a reduced surface roughness. The roughness attenuation with respect to the expected thermodynamical limit is determined to vary with the drawing stress following a power law. A striking anisotropic character of the height correlation is observed: glass surfaces thus retain a structural record of the direction of the flow to which the liquid was submitted

Induced pluripotent stem cells for candidate cell line selection of off-the-shelf natural killer cell therapy

Cell therapies provide a new strategy for the treatment and cure of debilitating diseases such as many forms of cancer, in which the standard lines of care have been unsuccessful. Although autologous CAR-T immunotherapy has shown resounding clinical efficacy, introduction of new treatments is hampered by regulatory, financial, technical, and resource constraints. Allogeneic cell therapies provide an alternative to autologous treatments for making CAR-immunotherapies more available to a broader patient demographic, with the ability to address many of the constraints of autologous cell therapies. Induced pluripotent stem cells (iPSCs) can serve as a self-renewable source of allogeneic starting material for long-term material supply for cell therapies. Creating clinically relevant iPSC master cell banks requires critical sourcing of starting material, somatic cells type selection, vendor qualification, and application of appropriate controls and analytical methods for screening donor material in compliance with FDA requirements. The establishment of good manufacturing practices is essential to create a reproducible and reliable procedure for generation of clinical iPSC master cell banks and subsequent differentiated cell types. These criteria for principles of GMP include raw material sourcing, reprogramming strategy determination, establishment of critical process parameters, critical quality attributes with essential quality control testing, and analytical methods consistent with FDA recommendations. With the benefit of the iPSCs capacity for self-renewal, there is the opportunity for expansive manufacturing capacity to meet clinical and commercialization demands; however, the ability to generate large numbers of differentiated intermediates and immune effector cells (e.g.., natural killer and T cells) from iPSCs can lead to bottlenecks in supply chain requirements. To address these process challenges, we assessed the hematopoietic differentiation capacity of gene edited iPSCs to various bioprocessing formats from 2D static cultures to 3D aggregate suspension cultures. We applied single-use scalable cell culture vessels, operational and analytical controls, and xeno-free, chemically-defined, culture conditions to generate hematopoietic progenitor cells (HPCs) during candidate cell line selection studies. This has resulted in robust differentiations to HPCs from many gene-edited IPSCs, which were further lineage committed to homogenous allogeneic iPSC-derived natural killer cells (iNKs) targeting CD19-positive cancer cells. The manufacturing process for iPSC-derived NK cells enabled comparability assessment of all gene edited iPSC candidate cell lines for feasibility of GMP facility fit, scale-out capacities, reduced cost-of-goods, xeno-free chemically defined media formulations, minimal batch-to-batch variability, operational controls for quality control (QC) and quality assurance (QA) methodologies essential for creating our “off-the-shelf” CAR-iNK therapies. These results use the critical principles of GMP applied during candidate cell line selection of Century’s CNTY-101 program. Our results highlight the technologies and controls needed to enable clinically-relevant production of Century’s iPSC-derived natural killer cell therapies

Research Report: Prevalence and Mechanism of Atrazine Resistance in Waterhemp from Nebraska

Waterhemp is a troublesome summer annual broadleaf weed species that has evolved resistance to glyphosate and other herbicide sites of action (SOA) in Nebraska, including to groups 2 (i.e., Classic, Pursuit, FirstRate), 4 (i.e., 2, 4-D), 5(i.e., atrazine) and 27 (e.g., Callisto, Laudis). The overall objectives of this study were to Evaluate the eficay of PRE applied atrazine, metribuzin and sulfentrazone to control Nebraska waterhemp populations; Evaluate the efficacy of POST applied atrazine to control Nebraska waterhemp populations; and Determine the mechanism of atrazine resistance in Nebraska waterhemp populations