Objectives/Goals: Acute myeloid leukemia (AML) is the second most common leukemia among pediatric populations. Approximately 15% of pediatric AML cases have KMT2A gene rearrangements (KMT2A-r), which confers a worse prognosis. Our goal is to better characterize the biologic landscape of KMT2A-r pediatric AML. Methods/Study Population: This study utilizes deidentified peripheral blood and/or bone marrow samples banked in the Children’s Mercy Tumor Bank Biorepository. We investigated four KMT2A-r pediatric AML patients and six patients with other AML subtypes using samples collected at diagnosis and remission that were stored in the “tumor bank.” In addition, we assessed 47 tumor bank samples from patients with other leukemia subtypes. We performed differential expression (DE) analysis on bulk RNA sequencing comparing KMT2A-r and all other AML subtypes, as well as single-cell RNA sequencing and proteomic analysis on the larger cohort. We then coalesced these data to better identify processes and pathways that are dysregulated in KMT2A-r AML, specifically aiming to find those that were contributing to leukemogenesis. Results/Anticipated Results: Transcriptomic analysis showed that HOXA10 and MEIS1, two genes associated with immature myeloid populations and KMT2A-r leukemias, were more highly transcribed in AMLs than other leukemias. In addition, our DE analysis showed significantly higher transcription of ITGA7, a gene shown to correlate with poorer prognosis in AML, in our KMT2A-r samples when compared to other AML subtypes. FAM46C, a tumor suppressor gene contributing to mRNA stabilization, was less highly expressed in KMT2A-r AML when compared to other AML subtypes. Of note, low expression of FAM46C is associated with poorer survival and treatment response in multiple myeloma, and our findings suggest it may also be relevant to AML. Proteomic analysis is currently in process. Discussion/Significance of Impact: Transcriptomic analysis identifies unique molecular features of pediatric KMT2A-r AML. We anticipate that our proteomic data will do the same and will also corroborate our RNA findings. Taken in combination, these results will provide a more complete picture of the specific mechanisms contributing to this aggressive leukemic subtype.

Social psychology is not a very politically diverse area of inquiry, something that could negatively affect the objectivity of social psychological theory and research, as Duarte et al. argue in the target article. This commentary offers a number of checks to help researchers uncover possible biases and identify when they are engaging in hypothesis confirmation and advocacy instead of hypothesis testing.

Adolescent psychopathology is commonly connected to marijuana use. How changes in these adolescent antecedents and in adolescent marijuana use are connected to patterns of marijuana use in the 20s is little understood. Another issue not clearly understood is psychopathology in the 30s as predicted by marijuana use in the 20s. This study sought to examine these two issues and the associations with marijuana disorder diagnoses using a longitudinal data set of 205 men with essentially annual reports. Individual psychopathology and family characteristics from the men's adolescence were used to predict their patterns of marijuana use across their 20s, and aspects of the men's psychopathology in their mid-30s were predicted from these patterns. Three patterns of marijuana use in the 20s were identified using growth mixture modeling and were associated with diagnoses of marijuana disorders at age 26 years. Parental marijuana use predicted chronic use for the men in adulthood. Patterns of marijuana use in the 20s predicted antisocial behavior and deviant peer association at age 36 years (controlling for adolescent levels of the outcomes by residualization). These findings indicate that differential patterns of marijuana use in early adulthood are associated with psychopathology toward midlife.

There was a strong consensus in the commentaries that animals' performances in metacognition paradigms indicate high-level decisional processes that cannot be explained associatively. Our response summarizes this consensus and the support for the idea that these performances demonstrate animal metacognition. We amplify the idea that there is an adaptive advantage favoring animals who can – in an immediate moment of difficulty or uncertainty – construct a decisional assemblage that lets them find an appropriate behavioral solution. A working consciousness would serve this function well. This explains why animals may have the functional equivalent of human declarative consciousness. However, like other commentators who were friendly to this equivalence, we approach carefully the stronger claims that animals' metacognitive performances imply full-blown self-awareness or phenomenal consciousness.

We discuss the commentators' interesting ideas for future research, as well as their intriguing ideas about the evolution and development of metacognition and its relation to theory of mind. We also discuss residual confusions about existing research and remaining methodological issues.

Researchers have begun to explore animals' capacities for uncertainty monitoring and metacognition. This exploration could extend the study of animal self-awareness and establish the relationship of self-awareness to other-awareness. It could sharpen descriptions of metacognition in the human literature and suggest the earliest roots of metacognition in human development. We summarize research on uncertainty monitoring by humans, monkeys, and a dolphin within perceptual and metamemory tasks. We extend phylogenetically the search for metacognitive capacities by considering studies that have tested less cognitively sophisticated species. By using the same uncertainty-monitoring paradigms across species, it should be possible to map the phylogenetic distribution of metacognition and illuminate the emergence of mind. We provide a unifying formal description of animals' performances and examine the optimality of their decisional strategies. Finally, we interpret animals' and humans' nearly identical performances psychologically. Low-level, stimulus-based accounts cannot explain the phenomena. The results suggest granting animals a higher-level decision-making process that involves criterion setting using controlled cognitive processes. This conclusion raises the difficult question of animal consciousness. The results show that animals have functional features of or parallels to human conscious cognition. Remaining questions are whether animals also have the phenomenal features that are the feeling/knowing states of human conscious cognition, and whether the present paradigms can be extended to demonstrate that they do. Thus, the comparative study of metacognition potentially grounds the systematic study of animal consciousness.

Transmission Electron Microscopy was applied to study HVPE template and MBE over-layers in plan-view and cross-section. It was observed that screw dislocations in the HVPE layers are decorated by small voids arranged along the screw axis. However, no voids were observed along screw dislocations in MBE overlayers grown with excess Ga, despite the fact that Ga droplets were observed on the layer surface as well as imbedded in the layer. By applying a direct reconstruction of the phase and amplitude of the scattered electron wave from a focal series of high-resolution images, the core structures of screw dislocations in both materials have been studied and show that all screw dislocations have filled cores. Dislocation cores in MBE samples grown Ga-rich and N-rich show no substantial differences and no stoichiometric change compared to the matrix. However, in HVPE materials, single atomic columns show substantial differences in intensities and indicate the possibility of Ga presence. These Ga-rich cores might be responsible for the attraction impurities forming voids in their close vicinity.

Dairy cows in confinement and pasture-based feeding systems were compared across 4 spring-calving and 3 fall-calving replicates for differences in reproduction, mastitis, and body condition scores. Each feeding system and replicate included both Jersey and Holstein cows. Cows in confinement were fed a total mixed ration with maize silage as the base forage along with a variety of concentrates. Cows on pasture were routinely supplemented with concentrates and were provided baled grass and/or legume silage when pastures were limiting. Breeding periods were for 75 days in spring or fall. Reproductive performance did not differ significantly due to feeding system but Jerseys had higher conception rates (59.6 vs. 49.5%) and overall pregnancy rates (78.0 vs. 57.9%) than Holsteins. Cows in confinement had significantly higher rates of clinical mastitis and culling for mastitis than cows on pasture. Within both feeding systems, Jerseys had less mastitis than Holsteins. Average body condition scores were higher for confinement cows than pasture cows except for one replicate. Jerseys maintained higher average body condition scores than Holsteins in all but one replicate. In summary, pastured cows produced less milk and had less mastitis but lower body condition scores than confinement cows. Holsteins produced more milk but were less likely to rebreed, had more mastitis, higher culling rates, and maintained lower body condition scores than Jerseys.

Transmission electron microscopy has been used to study defects formed in Mg-doped GaN crystals. Three types of crystals have been studied: bulk crystals grown by a high pressure and high temperature process with Mg added to the Ga solution and two types of crystals grown by metal-organic chemical vapor deposition (MOCVD) where Mg was either delta-doped or continuously doped. Spontaneous ordering was observed in bulk crystals. The ordering consists of Mg rich planar defects on basal planes separated by 10.4 nm and occurs only for growth in the N to Ga polar direction (000 N polarity). These planar defects exhibit the characteristics of stacking faults with a shift vector of a 1/3 [1 00] +c/2 but some other features identify these defects as inversion domains. Different type of defects were formed on the opposite site of the crystal (Ga to N polar direction), where the growth rate is also an order of magnitude faster compared to the growth with N-polarity. These defects are three-dimensional: pyramidal and rectangular, empty inside with Mg segregation on internal surfaces. The same types of defects seen for the two growth polarities in the bulk crystals were also observed in the MOCVD grown GaN samples with Mg delta doping, but were not observed in the crystals where Mg was added continuously.

A methodology for the preparation of porous scaffolds for tissue engineering using co-extrusion is presented. Poly(ε-caprolactone) is blended with poly(ethylene oxide) in a twin-screw extruder to form a two-phase material with micrometer-sized domains. Selective dissolution of the poly(ethylene oxide) with water results in a porous material. This method of polymer extrusion permits the preparation of scaffolds having continuous void space and controlled characteristic length scales without the use of potentially toxic organic solvents. A range of blend volume fractions results in co-continuous networks of polymer and void spaces. Annealing studies demonstrate that the characteristic pore size may be increased to larger than 100 μm. The mechanical properties of the scaffolds are characterized by a compressive modulus on the order of 1 MPa at low strains and approximately 10 MPa at higher strains. The results of osteoblast seeding suggest it is possible to use co-extrusion to prepare polymer scaffolds without the introduction of toxic contaminants.

Successive growth of thick GaN layers separated by either LT-GaN or LT-AlN interlayers have been investigated by transmission electron microscopy techniques. One of the objectives of this growth method was to improve the quality of GaN layers by reducing the dislocation density at the intermediate buffer layers that act as barriers to dislocation propagation. While the use of LT-AlN results in the multiplication of dislocations in the subsequent GaN layers, the LT-GaN reduces dislocation density. Based upon Burgers vector analysis, the efficiency of the buffer layers for the propagation of the different type of dislocations is presented. LT-AlN layer favor the generation of edge dislocations, leading to a highly defective GaN layer. On the other hand, the use of LT-GaN as intermediate buffer layers appears as a promising method to obtain high quality GaN layer.

We report on high quality GaN layers grown with the use of one intermediate layer. The defect analysis shows that the density of dislocation is only 8×107/cm2 in these layers, compared to over 1010/cm2 for layers grown without the intermediate layer (IL). Electron microscopy on cross-section samples shows that deposition under certain specific conditions of a low- temperature IL directly benefits the quality of the subsequently deposited GaN layer. The growth of the GaN top layer appears to be similar to growth observed for lateral epitaxial overgrowth layers. This first time observation opens the possibility for using standard growth methods of GaN compounds to achieve a dislocation density comparable to that achieved with lateral overgrowth epitaxy.

AlxGa1−xN {x=30% (doped and undoped), 45% (doped)} thin films were grown by MOCVD on ∼2 μm thick GaN layer using Al2O3 substrate. These films were designed to be the active parts of HFETs with nsμ product of about 1016(Vs)-1. The layers were then studied by means of transmission electron microscopy (TEM) techniques. In this paper, it is shown that the AlxGa1−xN layer thickness was non-uniform due to the presence of V-shaped defects within the AlxGa1−xN films. The nucleation of these V-shaped defects has taken place about 20 nm above the AlxGa1−xN/GaN interface. Many of these V-shaped defects were associated with the presence of the threading dislocations propagating from the GaN/Al2O3 interface. We show that the density of these V-shaped defects increases with the doping level and also with the Al mole fraction in the films. The formation mechanism of the V-shaped defects seems to be related to the concentration of dopants or other impurities at the ledges of the growing film. This suggestion is supported by high resolution TEM analysis. The growth front between the V-shaped defects in the lower Al concentration thin films was planar as compared with the three-dimensional growth in the doped, higher Al concentration film. This interpretation of the origin of the V-shaped defects is consistent with the observed lowering of the Schottky barrier height in n-doped AlGaN/Ni Schottky diodes.

Transmission electron microscopy was applied to cross-sectioned samples to study surface morphology, sample polarity and defect distribution in bulk GaN samples doped with Mg. These crystals were grown from a Ga melt under high hydrostatic pressure of Nitrogen. It was shown that the types of defects and their distribution along the c-axis depends strongly on sample polarity. Based on this finding the growth rate along the c-axis for the two polar directions was compared and shown to be approximately ten times larger for Ga polarity than for N-polarity. In the part of the crystals with Ga polarity pyramidal defects with a base consisting of high energy stacking faults were found. The parts of the crystals grown with Npolarity were either defect free or contained regularly spaced stacking faults. Growth of these regularly spaced cubic monolayers is polarity dependent; this structure was formed only for the growth with N polarity and only for the crystals doped with Mg. Formation of this superstructure is similar to the polytypoid structure formed in AlN crystals rich in oxygen. It is also likely that oxygen can decorate the cubic monolayers and compensate Mg. This newly observed structure may shed light on the difficulties of p-doping in GaN:Mg.

InGaN multiquantum wells grown by MOCVD on GaN have been investigated by transmission electron microscopy techniques and numerical analysis of high resolution (HREM) images. One objective of this research was to correlate the atomic structure and emission mechanisms of InGaN quantum well. The studied layers contained 13% or 20% In. It was shown that GaN/InGaN interfaces are rather rough and exhibit an oscillating contrast. Structural defects were found on these interfaces. The relative c-lattice parameter variation in the well was determined using numerical processing of HREM images. The lattice spacings appear to be larger than that expected from Vegard's law suggesting the presence of a biaxial strain. Further observations also revealed a redistribution of In within the well. Instead of a continous In-rich layer, quantum dots were often observed along the well with a regular spacing. The formation of these In-rich dots was not intented and their presence suggests either a periodic modulation of strain along the well or In-rich cluster formation.

Transmission electron microscopy was employed to study the effect of N/Ga flux ratio in the growth of GaN buffer layers on the structure of GaN epitaxial layers grown by molecular-beamepitaxy (MBE) on sapphire. The dislocation density in GaN layers was found to increase from 1×1010 to 6×1010 cm−2 with increase of the nitrogen flux from 5 to 35 sccm during the growth of the GaN buffer layer with otherwise the same growth conditions. All GaN layers were found to contain inversion domain boundaries (IDBs) originated at the interface with sapphire and propagated up to the layer surface. Formation of IDBs was often associated with specific defects at the interface with the substrate. Dislocation generation and annihilation were shown to be mainly growth-related processes and, hence, can be controlled by the growth conditions, especially during the first growth stages. The decrease of electron Hall mobility and the simultaneous increase of the intensity of “green” luminescence with increasing dislocation density suggest that dislocation-related deep levels are created in the bandgap.

AlxGa1−xN {x=30% (doped and undoped), 45% (doped)} thin films were grown by MOCVD on ∼2 µm thick GaN layer using Al2O3 substrate. These films were designed to be the active parts of HFETs with nsí product of about 1016(Vs)−1. The layers were then studied by means of transmission electron microscopy (TEM) techniques. In this paper, it is shown that the AlxGa1−xN layer thickness was non-uniform due to the presence of Vshaped defects within the AlxGa1−xN films. The nucleation of these V-shaped defects has taken place about 20 nm above the AlxGa1−xN/aN interface. Many of these Vshaped defects were associated with the presence of the threading dislocations propagating from the GaN/Al2O3 interface. We show that the density of these V-shaped defects increases with the doping level and also with the Al mole fraction in the films. The formation mechanism of the V-shaped defects seems to be related to the concentration of dopants or other impurities at the ledges of the growing film. This suggestion is supported by high resolution TEM analysis. The growth front between the V-shaped defects in the lower Al concentration thin films was planar as compared with F99W3.77 the three-dimensional growth in the doped, higher Al concentration film. This interpretation of the origin of the V-shaped defects is consistent with the observed lowering of the Schottky barrier height in n-doped AlGaN/Ni Schottky diodes.