Investigating the Migratory Behavior of Soybean Looper, a Major Pest of Soybean, through Comparisons with the Corn Pest Fall Armyworm Using Mitochondrial Haplotypes and a Sex-Linked Marker.

The Noctuid moth soybean looper (SBL), Chrysodeixis includens (Walker), is an economically important pest of soybean (Glycine max (Linnaeus) Merrill). Because it is not known to survive freezing winters, permanent populations in the United States are believed to be limited to the southern regions of Texas and Florida, yet its geographical range of infestations annually extend to Canada. This indicates annual migrations of thousands of kilometers during the spring and summer growing season. This behavior is like that of the fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), also a Noctuid that is a major global pest of corn. SBL and FAW are projected to have very similar distributions of permanent populations in North America based on climate suitability modeling and the overlap in the distribution of their preferred host plants (corn and soybean). It therefore seems likely that the two species will display similar migratory behavior in the United States. This was tested by identifying genetic markers in SBL analogous to those successfully used to delineate FAW migratory pathways and comparing the distribution patterns of the markers from the two species. Contrary to expectations, the results indicate substantial differences in migratory behavior that appear to be related to differences in the timing of corn and soybean plantings. These findings underscore the importance of agricultural practices in influencing pest migration patterns, in particular the timing of host availability relative to mean seasonal air transport patterns.

Evidence for Two Soybean Looper Strains in the United States with Limited Capacity for Cross-Hybridization.

The noctuid moth soybean looper (SBL), Chrysodeixis includens (Walker) is an economically important pest of soybeans (Glycine max (L.) Merr.) in the southeastern United States. It has characteristics that are of particular concern for pest mitigation that include a broad host range, the capacity for annual long-distance flight, and resistance in some populations to important pesticides such as pyrethroids and chitin synthesis inhibitor. The biology of SBL in the United States resembles that of the fellow noctuid fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), a major pest of corn and several other crops. FAW exhibits a population structure in that it can be divided into two groups (host strains) that differ in their host preferences but are broadly sympatric and exhibit incomplete reproductive isolation. In this paper, strategies used to characterize the FAW strains were applied to SBL to assess the likelihood of population structure in the United States. Evidence is presented for two SBL strains that were defined phylogenetically and display differences in the proportions of a small set of genetic markers. The populations exhibit evidence of reproductive barriers sufficient to allow persistent asymmetry in the distribution of mitochondrial haplotypes. The identified molecular markers will facilitate studies characterizing the behaviors of these two populations, with relevance to pest mitigation and efforts to prevent further dispersal of the resistance traits.

Effects of Floquet Engineering on the Coherent Exciton Dynamics in Monolayer WS2.

Coherent optical manipulation of electronic bandstructures via Floquet Engineering is a promising means to control quantum systems on an ultrafast time scale. However, the ultrafast switching on/off of the driving field comes with questions regarding the limits of the Floquet formalism (which is defined for an infinite periodic drive) through the switching process and to what extent the transient changes can be driven adiabatically. Experimentally addressing these questions has been difficult, in large part due to the absence of an established technique to measure coherent dynamics through the duration of the pulse. Here, using multidimensional coherent spectroscopy we explicitly excite, control, and probe a coherent superposition of excitons in the K and K' valleys in monolayer WS2. With a circularly polarized, red-detuned pump pulse, the degeneracy of the K and K' excitons can be lifted, and the phase of the coherence rotated. We directly measure phase rotations greater than π during the 100 fs driving pulse and show that this can be described by a combination of the AC-Stark shift of excitons in one valley and the Bloch-Siegert shift of excitons in the opposite valley. Despite showing a smooth evolution of the phase that directly follows the intensity envelope of the nonresonant pump pulse, the process is not perfectly adiabatic. By measuring the magnitude of the macroscopic coherence as it evolves before, during, and after the nonresonant pump pulse we show that there is additional decoherence caused by power broadening in the presence of the nonresonant pump. This nonadiabaticity arises as a result of interactions with the otherwise adiabatic Floquet states and may be a problem for many applications, such as manipulating qubits in quantum information processing; however, these measurements also suggest ways such effects can be minimized or eliminated.

The impact of thiamethoxam on the feeding and behavior of 2 soybean herbivore feeding guilds.

Over the past few decades, inadvertent consequences have stemmed from the intensified use of neonicotinoids in agroecosystems. Neonicotinoid applications can result in both positive (e.g., reduced persistent virus transmission) and negative (e.g., increased host susceptibility) repercussions exhibiting ambiguity for their use in crop production. In soybean, aspects of neonicotinoid usage such as the impact on nonpersistent virus transmission and efficacy against nontarget herbivores have not been addressed. This study evaluated the interaction between the neonicotinoid thiamethoxam and soybean variety and the impact on different pest feeding guilds. Feeding and behavioral bioassays were conducted in the laboratory to assess the effect of thiamethoxam on the mortality and weight gain of the defoliator, Chrysodeixis includens (Walker). Bioassays evaluated impacts dependent and independent of soybean tissue, in addition to both localized and systemic efficacy within the soybean plant. Additionally, using the electrical penetration graph technique (EPG), the probing behavior of 2 piercing-sucking pests, Aphis gossypii Glover and Myzus persicae (Sulzer), was observed. Results from defoliator bioassays revealed thiamethoxam had insecticidal activity against C. includens. Distinctions in thiamethoxam-related mortality between bioassays dependent and independent of soybean tissue (~98% versus ~30% mortality) indicate a contribution of the plant towards defoliator-related toxicity. Observations of defoliator feeding behavior showed a preference for untreated soybean tissue relative to thiamethoxam-treated tissue, suggesting a deterrent effect of thiamethoxam. EPG monitoring of probing behavior exhibited a minimal effect of thiamethoxam on piercing-sucking herbivores. Findings from this study suggest neonicotinoids like thiamethoxam may provide some benefit via insecticidal activity against nontarget defoliators.

Elucidating the insecticidal mechanisms of zein nanoparticles on Anticarsia gemmatalis (Lepidoptera: Erebidae).

Previous research suggested that positively charged zein nanoparticles [(+)ZNP] were toxic to neonates of Anticarsia gemmatalis Hübner and deleterious to noctuid pests. However, specific modes of action for ZNP have not been elucidated. Diet overlay bioassays attempted to rule out the hypothesis that A. gemmatalis mortality was caused by surface charges from component surfactants. Overlay bioassays indicated that negatively charged zein nanoparticles [(-)ZNP] and its anionic surfactant, sodium dodecyl sulfate (SDS), exhibited no toxic effects when compared to the untreated check. Nonionic zein nanoparticles [(N)ZNP] appeared to increase mortality compared to the untreated check, though larval weights were unaffected. Overlay results for (+)ZNP and its cationic surfactant, didodecyldimethylammonium bromide (DDAB), were found to be consistent with former research indicating high mortalities, and thus, dosage response curves were conducted. Concentration response tests found the LC50 for DDAB on A. gemmatalis neonates was 208.82 a.i./ml. To rule out possible antifeedant capabilities, dual choice assays were conducted. Results indicated that neither DDAB nor (+)ZNP were antifeedants, while SDS reduced feeding when compared to other treatment solutions. Oxidative stress was tested as a possible mode of action, with antioxidant levels used as a proxy for reactive oxygen species (ROS) in A. gemmatalis neonates, which were fed diet treated with different concentrations of (+)ZNP and DDAB. Results indicated that both (+)ZNP and DDAB decreased antioxidant levels compared to the untreated check, suggesting that both (+)ZNP and DDAB may inhibit antioxidant levels. This paper adds to the literature on potential modes of action by biopolymeric nanoparticles.

Catalyzing systemic movement of inward rectifier potassium channel inhibitors for antifeedant activity against the cotton aphid, Aphis gossypii (Glover).

BACKGROUND: The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is a destructive agricultural pest, capable of photosynthate removal and plant virus transmission. Therefore, we aimed to test the antifeedant properties of small-molecule inhibitors of inward rectifier potassium (Kir) channels expressed in insect salivary glands and develop an approach for enabling systemic movement of lipophilic Kir inhibitors. RESULTS: Two Kir channel inhibitors, VU041 and VU730, reduced the secretory activity of the aphid salivary glands by 3.3-fold and foliar applications of VU041 and VU730 significantly (P < 0.05) increased the time to first probe, total probe duration, and nearly eliminated phloem salivation and ingestion. Next, we aimed to facilitate systemic movement of VU041 and VU730 through evaluation of a novel natural product based solubilizer containing rubusoside that was isolated from Chinese sweet leaf (Rubus suavissimus) plants. A single lower leaf was treated with Kir inhibitor soluble liquid (KI-SL) and systemic movement throughout the plant was verified via toxicity bioassays and changes to feeding behavior through the electrical penetration graph (EPG) technique. EPG data indicate KI-SL significantly reduced ability to reach E1 (phloem salivation) and E2 (phloem ingestion) waveforms and altered plant probing behavior when compared to the untreated control. High-performance liquid chromatography (HPLC) analysis indicated the presence of VU041 and VU730 in the upper leaf tissue of these plants. Together, these data provide strong support that incorporation of rubusoside with Kir inhibitors enhanced translaminar and translocation movement through the plant tissue. CONCLUSION: These data further support hemipteran Kir channels as a target to prevent feeding and induce toxicity. Further, these studies highlight a novel delivery approach for generating plant systemic activity of lipophilic insecticides. © 2022 Society of Chemical Industry.

Evaluation of Hemp (Cannabis sativa) (Rosales: Cannabaceae) as an Alternative Host Plant for Polyphagous Noctuid Pests.

Hemp (Cannabis sativa L.) is a reemerging crop in the United States with increasing outdoor acreage in many states. This crop offers a potential host for polyphagous, defoliating lepidopteran pests currently present in Louisiana. The ability of soybean looper [Chrysodeixis includens (Walker)] (Lepidoptera: Noctuidae), fall armyworm [Spodoptera frugiperda (J.E. Smith)] (Lepidoptera: Noctuidae), and beet armyworm [Spodoptera exigua (Hübner)] to develop and reproduce on hemp was investigated in this study. Insects were reared on two hemp varieties, Maverick and Pipeline, as well as documented host plants soybean [Glycine max (L.) Merr.] (Fabales: Fabaceae) variety UA5414RR and cowpea [Vigna unguiculata (L.)] (Fabales: Fabaceae) variety Quickpick Pinkeye. Larvae of all three species reared on 'Maverick' had significantly faster preadult developmental times compared to the other hosts. Chrysodeixis includens larvae fed excised leaves of 'Maverick' and 'Pipeline' experienced higher intrinsic and finite rates of increase, higher net reproductive rates, and faster mean generation and doubling times. Spodoptera frugiperda larvae reared on 'Maverick', 'Pipeline', and 'UA5414RR' had higher intrinsic and finite rates of increase, higher net reproductive rates, and faster mean generation and doubling times compared to 'Quickpick Pinkeye'. Spodoptera exigua larvae had the highest survivorship on 'Maverick' and similar, positive lifetable statistics when reared on 'Maverick' and 'Pipeline'. The results of this study indicate hemp is an alternative host plant that has the potential to influence the population dynamics of C. includens, S. frugiperda, and S. exigua in Louisiana agroecosystems they co-occur in.

Interactions between Fermi polarons in monolayer WS2.

Interactions between quasiparticles are of fundamental importance and ultimately determine the macroscopic properties of quantum matter. A famous example is the phenomenon of superconductivity, which arises from attractive electron-electron interactions that are mediated by phonons or even other more exotic fluctuations in the material. Here we introduce mobile exciton impurities into a two-dimensional electron gas and investigate the interactions between the resulting Fermi polaron quasiparticles. We employ multi-dimensional coherent spectroscopy on monolayer WS2, which provides an ideal platform for determining the nature of polaron-polaron interactions due to the underlying trion fine structure and the valley specific optical selection rules. At low electron doping densities, we find that the dominant interactions are between polaron states that are dressed by the same Fermi sea. In the absence of bound polaron pairs (bipolarons), we show using a minimal microscopic model that these interactions originate from a phase-space filling effect, where excitons compete for the same electrons. We furthermore reveal the existence of a bipolaron bound state with remarkably large binding energy, involving excitons in different valleys cooperatively bound to the same electron. Our work lays the foundation for probing and understanding strong electron correlation effects in two-dimensional layered structures such as moiré superlattices.

Profile of commercialized aphicides on the survivorship and feeding behavior of the cotton aphid, Aphis gossypii.

The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is one of the most destructive agricultural pests due to photosynthate removal and horizontal transmission of plant viruses. Horizontal transmission of plant viruses by aphids occurs during distinct feeding behavioral events, such as probing for non-persistent viruses or phloem feeding for persistent viruses. We employed toxicity bioassays and electrical penetration graph (EPG) methodology to compare toxicity and quantify changes to feeding behavior and toxicity of A. gossypii after exposure to commercialized aphicides. Commercialized aphicides containing flupyradifurone, sulfoxaflor, thiamethoxam, thiamethoxam + lambda cyhalothrin, and bifenthrin induced >90% aphid mortality within 4 h of exposure. Flupyradifurone was the most acutely toxic aphicide studied with an LT50 of 8.9 min after exposure, which was approximately 3-fold lower than bifenthrin and thiamethoxam + lambda cyhalothrin. This was supported by our EPG results that showed a significant reduction in the proportion of aphids that continued to probe on cotton 4 h after exposure to flonicamid, thiamethoxam, flupyradifurone, bifenthrin, and thiamethoxam + lambda cyhalothrin. The commercialized aphicides containing spirotetramat, flonicamid, thiamethoxam, flupyradifurone, bifenthrin, sulfoxaflor, and pymetrozine significantly (P < 0.05) decreased the time to first probe when compared to the untreated control. Lastly, E1 (phloem salivation) and E2 (phloem ingestion) waveforms were significantly (P < 0.05) reduced for flupyradifurone, flonicamid, thiamethoxam, sulfoxaflor, and thiamethoxam. These data provide a comparative study for the development of new aphicides aiming to induce acute lethality and reduce aphid transmission of plant viruses.

Life History of Chrysodeixis includens (Lepidoptera: Noctuidae) on Positively Charged Zein Nanoparticles.

Research indicates that nanoparticles can be an effective agricultural pest management tool, though unintended effects on the insect must be evaluated before their use in agroecosystems. Chrysodeixis includens (Walker) was used as a model to evaluate chronic parental and generational exposure to empty, positively charged zein nanoparticles ((+)ZNP) and methoxyfenozide-loaded zein nanoparticles (+)ZNP(MFZ) at low-lethal concentrations. To determine concentration limits, an acute toxic response test on meridic diet evaluated (+)ZNP(MFZ) and technical grade methoxyfenozide using two diet assay techniques. No differences in acute toxicity were observed between the two treatments within their respective bioassays. With these results, population dynamics following chronic exposure to low-lethal concentrations were evaluated. Parental lifetables evaluated cohorts of C. includens reared on diet treated with LC5 equivalents of (+)ZNP, (+)ZNP(MFZ), or technical grade methoxyfenozide. Compared to technical grade methoxyfenozide, (+)ZNP(MFZ) lowered both the net reproductive rate and intrinsic rate of increase, and was more deleterious to C. includens throughout its lifespan. This was contrasted to (+)ZNP, which showed no differences in population dynamics when compared with the control. To evaluate chronic exposure to (+)ZNP, generational lifetables reared cohorts of C. includens on LC5 equivalent values of (+)ZNP and then took the resulting offspring to be reared on either (+)ZNP or untreated diet. No differences in lifetable statistics were observed between the two treatments, suggesting that (+)ZNP at low ppm do not induce toxic generational effects. This study provides evidence into the effects of nanodelivered methoxyfenozide and the generational impact of (+)ZNP.

Predator-Pest Dynamics of Arthropods Residing in Louisiana Soybean Agroecosystems.

Over the past two decades, management practices within Louisiana soybean production have shifted. Successful application of an integrated pest management (IPM) strategy requires an understanding of how these changes have affected predator-pest dynamics. Surveys monitoring foliage-foraging arthropod populations in soybean took place across six locations within Louisiana over six years (2012-2014 and 2015-2018). Temporal associations of pest groups, defoliating and piercing-sucking, and predator groups relating to soybean phenology were observed. Additionally, soybean maturity groups (III, IV, and V) were also evaluated to delineate potential differences. Results indicated higher abundances of piercing-sucking pests compared to defoliating pests across both datasets (2012-2014 and 2015-2018). Pest groups were more abundant in later soybean reproductive periods, mainly attributed to Chrysodeixis includens and Piezodorus guildinii. Predator populations were mainly comprised of Araneae and Geocoridae throughout the survey periods. From 2015 to 2018, soybean growth had a significant effect on total predator abundance with more predators present at the pod-fill and soybean maturity stage. Correlations between total pest abundance and total predators exhibited a moderate positive linear relationship. Soybean maturity groups only influenced piercing-sucking pest abundance, with later maturing groups (IV and V) having higher numbers. Thus, control tools and tactics aimed at controlling late season pests should be modified to avoid reducing predator populations.

Sugarcane Aphid (Hemiptera: Aphididae) on Sorghum. I. Population Characteristics and Dispersion Patterns in Relation to Different Sample Unit Sizes.

The sugarcane aphid, Melanaphis sacchari (Zehntner), has emerged as a serious pest of sorghum in the United States. Field trials were conducted in Louisiana and South Carolina in 2016-2018 to investigate its population characteristics and distribution patterns in relation to four sample unit sizes (three circular and one leaf based). Sugarcane aphid populations usually progressed through a phase of rapid rise followed by a phase of rapid decline within a span of 5-6 wk, with peak density determined by sorghum cultivars and climatic conditions. Peak population densities for susceptible cultivars were 1.9-14.9× that for resistant cultivars on a per plant basis. Melanaphis sacchari tended to concentrate on the lower green leaf nodes early in the infestation, with the distribution shifting toward higher green leaf nodes as the infestation progressed. Aphid densities per cm2 at the basal and middle sections were about twice as high as at the distal section of leaves. The proportions of infested sample units were fitted to the Wilson-Room binomial model that incorporates the effect of density on clumping pattern. For a specific sample unit size, clumping patterns were similar across cultivars, years, and leaf positions, but varied across infestation stages. For a fixed aphid density per sample unit, the proportion of infested sample units decreased with increasing sample unit size. For a fixed aphid density per cm2, proportion infested increased with increasing sample unit size, indicating less clumping with a larger sample unit size. Field sampling time and efficiency between samplers were quantified.

Effects of engineered lignin-graft-PLGA and zein-based nanoparticles on soybean health.

The majority of published research on the effect of engineered nanoparticles on terrestrial plant species is focused on inorganic nanoparticles, with the effects of organic polymeric nanoparticles (NP) on plants remaining largely unexplored. It is critical to understand the impact of polymeric NPs on plants if these particles are to be used as agrochemical delivery systems. This study investigates the effect of biodegradable polymeric lignin-based nanoparticles (LNPs) and zein nanoparticles (ZNP) on soybean plant health. The LNPs (114 ± 3.4 nm, -53.8 ± 6.9 mV) were synthesized by emulsion evaporation from lignin-graft-poly(lactic-co-glycolic) acid, and ZNPs (142 ± 3.9 nm and + 64.5 ± 4.7 mV) were synthesized by nanoprecipitation. Soybeans were grown hydroponically and treated with 0.02, 0.2, and 2 mg/ml of LNPs or ZNPs at 28 days after germination. Plants were harvested after 1, 3, 7 and 14 days of particle exposure and analyzed for root and stem length, chlorophyll concentration, dry biomass of roots and stem, nutrient uptake and plant ROS. Root and stem length, chlorophyll and stem biomass did not differ significantly between treatments and controls for LNPs-treated plants at all concentrations, and at low doses of ZNPs. At 2 mg/ml ZNPs, the highest concentration tested, after 7 days of treatment chlorophyll levels and root biomass increased and stem length was reduced in comparison to the control. Nutrient uptake was largely unaffected at 0.02 and 0.2 mg/ml NPs. A concentration-dependent increase in the oxidative stresss was detected, especially in the ZNP treated plants. Overall, LNPs and ZNPs had a minimum impact on soybean health especially at low and medium doses. To our knowledge this is the first study to show the effect of zein and lignin based polymeric NPs designed for agrochemical delivery on soybean plant health.

In-phase sub-Nyquist lenslet arrays encoded onto spatial light modulators.

When encoding diffractive lenses onto a spatial light modulator (SLM), there is a Nyquist limit to the smallest focal length that can be formed. When this limit is surpassed, a two-dimensional array of lenslets is formed. There have been very few discussions on the performance of these lenslets. In this work, we focus on the phase distribution of these lenses in the array. We show that, for certain values of the focal length, the lenslets are all in perfect phase. We show that this situation happens for a total number of N/4 different discrete equidistant sub-Nyquist focal lengths, where N×N is the number of pixels in the SLM. We find other distances in between where the array is composed of two sets of lenslets with a relative π phase among them. Finally, we illustrate these phase distributions in the application to generate an array of vortex producing lenses. We expect that these results might be useful for high-accuracy interferometric or multiple imaging where this phase must be exactly the same for each replica.

Evaluating Behavioral Responses of Selected Stink Bugs (Hemiptera: Pentatomidae) to Spinosad.

Southern green stink bug, Nezara viridula (L.) and redbanded stink bug, Piezodorus guildinii (Westwood) are two of the most important seed sucking pests affecting Louisiana soybean production and rice stink bug, Oebalus pugnax (F.) is an important late season pest in Louisiana rice. Exploration of chemicals that exhibit attraction or repellent activities toward major stink bug species would be beneficial in developing push-pull strategies. Spinosad is a commercially available natural insecticide that may have arrestant, attractant, or phagostimulant properties against stink bugs. To test this, a series of laboratory experiments were conducted to investigate the tactile, olfactory, and feeding responses of these stink bugs toward two commercial spinosad products (Entrust and Tracer) and technical grade spinosad. In tactile assays, female and male redbanded stink bug were arrested by Entrust, Tracer, and technical grade spinosad, whereas only rice stink bug and southern green stink bug males were arrested by Entrust. Y-tube assays revealed no attraction to any of the products by either male or female rice stink bug, redbanded stink bug, or southern green stink bug. In paired (treated or untreated soybean seed) feeding preference experiments, southern green stink bug showed no preference for any treatment, whereas redbanded stink bug fed more on Entrust- and Tracer-treated seed. From these results, spinosad appears to have an arrestant and phagostimulant effect on redbanded stink bug in the laboratory.

Elucidating Efficacy of Ingested Positively Charged Zein Nanoparticles Against Noctuidae.

A meridic diet overlay bioassay using empty, positively charged zein nanoparticles ((+)ZNP) was performed on soybean looper (Chrysodeixis includens (Walker)), tobacco budworm (Heliothis virescens (F.)), and velvetbean caterpillar (Anticarsia gemmatalis Hübner) (Lepidoptera: Noctuidae). Assessment of effects on mortality and development weights 7 d after ingestion of (+)ZNP were evaluated on larvae of each species. Treatments involved different concentrations, with H. virescens and A. gemmatalis offered 0 and 3,800 ppm (+)ZNP, whereas C. includens colonies were offered 0, 630, 1,260, and 2,520 ppm (+)ZNP. Mortality of A. gemmatalis and C. includens increased after ingestion of the highest (+)ZNP concentrations, while H. virescens neonate mortality was unaffected. Neonate and third-instar weights of A. gemmatalis and C. includens, and neonate H. virescens, decreased with high (+)ZNP concentrations. Following mortality results from A. gemmatalis neonates, a concentration response test was performed using a range of (+)ZNP concentrations. The LC50 for A. gemmatalis was 1,478 ppm. The potential of (+)ZNP as a pest management tactic is discussed.

Supertransport of excitons in atomically thin organic semiconductors at the 2D quantum limit.

Long-range and fast transport of coherent excitons is important for the development of high-speed excitonic circuits and quantum computing applications. However, most of these coherent excitons have only been observed in some low-dimensional semiconductors when coupled with cavities, as there are large inhomogeneous broadening and dephasing effects on the transport of excitons in their native states in materials. Here, by confining coherent excitons at the 2D quantum limit, we first observed molecular aggregation-enabled 'supertransport' of excitons in atomically thin two-dimensional (2D) organic semiconductors between coherent states, with a measured high effective exciton diffusion coefficient of ~346.9 cm2/s at room temperature. This value is one to several orders of magnitude higher than the values reported for other organic molecular aggregates and low-dimensional inorganic materials. Without coupling to any optical cavities, the monolayer pentacene sample, a very clean 2D quantum system (~1.2 nm thick) with high crystallinity (J-type aggregation) and minimal interfacial states, showed superradiant emission from Frenkel excitons, which was experimentally confirmed by the temperature-dependent photoluminescence (PL) emission, highly enhanced radiative decay rate, significantly narrowed PL peak width and strongly directional in-plane emission. The coherence in monolayer pentacene samples was observed to be delocalised over ~135 molecules, which is significantly larger than the values (a few molecules) observed for other organic thin films. In addition, the supertransport of excitons in monolayer pentacene samples showed highly anisotropic behaviour. Our results pave the way for the development of future high-speed excitonic circuits, fast OLEDs, and other optoelectronic devices.

Persistent coherence of quantum superpositions in an optimally doped cuprate revealed by 2D spectroscopy.

Quantum materials displaying intriguing magnetic and electronic properties could be key to the development of future technologies. However, it is poorly understood how the macroscopic behavior emerges in complex materials with strong electronic correlations. While measurements of the dynamics of excited electronic populations have been able to give some insight, they have largely neglected the intricate dynamics of quantum coherence. Here, we apply multidimensional coherent spectroscopy to a prototypical cuprate and report unprecedented coherent dynamics persisting for ~500 fs, originating directly from the quantum superposition of optically excited states separated by 20 to 60 meV. These results reveal that the states in this energy range are correlated with the optically excited states at ~1.5 eV and point to nontrivial interactions between quantum many-body states on the different energy scales. In revealing these dynamics and correlations, we demonstrate that multidimensional coherent spectroscopy can interrogate complex quantum materials in unprecedented ways.

The Lipid Flippases ALA4 and ALA5 Play Critical Roles in Cell Expansion and Plant Growth.

Aminophospholipid ATPases (ALAs) are lipid flippases involved in transporting specific lipids across membrane bilayers. Arabidopsis (Arabidopsis thaliana) contains 12 ALAs in five phylogenetic clusters, including four in cluster 3 (ALA4-ALA7). ALA4/5 and ALA6/7, are expressed primarily in vegetative tissues and pollen, respectively. Previously, a double knockout of ALA6/7 was shown to result in pollen fertility defects. Here we show that a double knockout of ALA4/5 results in dwarfism, characterized by reduced growth in rosettes (6.5-fold), roots (4.3-fold), bolts (4.5-fold), and hypocotyls (2-fold). Reduced cell size was observed for multiple vegetative cell types, suggesting a role for ALA4/5 in cellular expansion. Members of the third ALA cluster are at least partially interchangeable, as transgenes expressing ALA6 in vegetative tissues partially rescued ala4/5 mutant phenotypes, and expression of ALA4 transgenes in pollen fully rescued ala6/7 mutant fertility defects. ALA4-GFP displayed plasma membrane and endomembrane localization patterns when imaged in both guard cells and pollen. Lipid profiling revealed ala4/5 rosettes had perturbations in glycerolipid and sphingolipid content. Assays in yeast revealed that ALA5 can flip a variety of glycerolipids and the sphingolipid sphingomyelin across membranes. These results support a model whereby the flippase activity of ALA4 and ALA5 impacts the homeostasis of both glycerolipids and sphingolipids and is important for cellular expansion during vegetative growth.

Encoding lenses with focal lengths lower than the Nyquist limit using high phase-modulation displays.

Liquid crystal displays allow the easy implementation of diffractive optical elements. However, the shortest focal lengths for lenses are limited by Nyquist conditions. In this work, we show that focal lengths much lower than this Nyquist limit can be encoded onto devices having a large phase-dynamic range. Experimental results are included with a display showing 10π phase modulation reducing the Nyquist limit by a factor of about 1/10.