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Additive manufacturing offers reduced lead time between design and manufacturing. Fused filament fabrication, the most common form of material extrusion additive manufacturing, enables the production of custom-made parts with complex geometry. Despite the numerous advantages of additive manufacturing, reliability, reproducibility, and achievement of isotropic bulk properties in part remains challenging. We investigated the tensile behavior of a model polycarbonate system to explore what leads to different tensile properties, including sources of ductile versus brittle fracture. We utilized a one factor at a time (OFAT) design of experiments (DOE), printed single road-width boxes, and performed tensile tests on specimens from these boxes. Additionally, we characterized the cross-sections of parts printed under different conditions and their subsequent fracture behavior. The results demonstrate that isotropic bulk properties are achievable by printing at high speeds, and provide mechanisms to explain why. Highlights * Printing at high speeds leads to improved mechanical properties. * Printed samples undergo a mix of ductile and brittle failure. * Jagged fracture path is associated with superior adhesion. * High layer times lead to worse interfacial bonding. KEYWORDS additive manufacturing, fracture, mechanical properties, microscopy, voids, 1 | INTRODUCTION Material extrusion is the most widely used form of additive manufacturing (AM), with desktop scale thermally-driven fused filament fabrication (FFF) being the most common form of material [...]

Economic and environmental costs are assessed for four different plastics manufacturing processes, including cold and hot runner molding as well as stock and upgraded material extrusion three dimensional (3D) printers. A larger stock 3D printer was found to provide a melting capacity of 14.4 ml/h, while a smaller printer with an upgraded extruder had a melting capacity of 36 ml/h. 3D printing at these maximum melting capacities resulted in specific energy consumption (SEC) of 16.5 and 5.28 kWh/kg, respectively, with the latter value being less than 50% of the lowest values reported in the literature. Even so, analysis of these respective processes found them to be only 2.9% and 3.8% efficient relative to their theoretical minimum energy requirements. By comparison, cold and hot runner molding with an all-electric machine had SEC of 1.28 and 0.929 kWh/kg, respectively, with efficiencies of 9.9% and 13.6% relative to the theoretical minima. Breakeven analysis considering the cost and carbon footprint of mold tooling found injection molding was preferable at a production quantity of around 70,000 units. Parametric analysis of model inputs indicates that the breakeven quantities are robust with respect to carbon tax incentives but highly dependent on mold costs, labor costs, and part size. Dimensional and mechanical properties of the molded and 3D printed specimens are also characterized and discussed. KEYWORDS additive manufacturing, plastics molding, specific energy consumption, 1 | INTRODUCTION Society is increasingly aware of the need for sustainable solutions across all aspects of modern life. To the extent that this increased awareness does not drive organic [...]

In the United States, [approximately equal to]37 million cases of coronavirus disease (COVID-19) and >620,000 deaths had been reported as of June 30, 2021 (1). Given the critical role of [...]

Adaptation of the islet [beta] cell insulin-secretory response to changing insulin demand is critical for blood glucose homeostasis, yet the mechanisms underlying this adaptation are unknown. Here, we have shown that nutrient-stimulated histone acetylation plays a key role in adapting insulin secretion through regulation of genes involved in [beta] cell nutrient sensing and metabolism. Nutrient regulation of the epigenome occurred at sites occupied by the chromatin-modifying enzyme lysine-specific demethylase 1 (Lsd1) in islets. [beta] Cell-specific deletion of Lsd1 led to insulin hypersecretion, aberrant expression of nutrient-response genes, and histone hyperacetylation. Islets from mice adapted to chronically increased insulin demand exhibited shared epigenetic and transcriptional changes. Moreover, we found that genetic variants associated with type 2 diabetes were enriched at LSD1-bound sites in human islets, suggesting that interpretation of nutrient signals is genetically determined and clinically relevant. Overall, these studies revealed that adaptive insulin secretion involves Lsd1-mediated coupling of nutrient state to regulation of the islet epigenome., Introduction The ability to regulate nutrient metabolism in response to feeding and fasting is necessary for metabolic homeostasis. Nutrient utilization is acutely regulated by hormones and metabolites that change in [...]

The most common movements associated with tardive dyskinesia (TD) are in the oral regions and include puckering, chewing, grimacing, and tongue protrusions. It is also common to see choreiform movements [...]

Edwin Kessler III was born in Brooklyn, New York, on December 2, 1928, the oldest of three sons born to Edwin Kessler Jr. and Marie Rosa Weil. He passed away [...]

Dating the Tree of Life has now become central to relating patterns of biodiversity to key processes in Earth history such as plate tectonics and climate change. Regions with a Mediterranean climate have long been noted for their exceptional species richness and high endemism. How and when these biota assembled can only be answered with a good understanding of the sequence of divergence times for each of their components. A critical aspect of dating by using molecular sequence divergence is the incorporation of multiple suitable age constraints. Here, we show that only rigorous phylogenetic analysis of fossil taxa can lead to solid calibration and, in turn, stable age estimates, regardless of which of 3 relaxed clock-dating methods is used. We find that Proteaceae, a model plant group for the Mediterranean hotspots of the Southern Hemisphere with a very rich pollen fossil record, diversified under higher rates in the Cape Floristic Region and Southwest Australia than in any other area of their total distribution. Our results highlight key differences between Mediterranean hotspots and indicate that Southwest Australian biota are the most phylogenetically diverse but include numerous lineages with low diversification rates. biodiversity | diversification rates | fossil calibration | molecular dating | Proteaceae

Tribe Macadamieae (91 spp., 16 genera; Proteaceae) is widespread across the southern hemisphere on all major fragments of Gondwana except New Zealand and India. Macadamia is cultivated outside its natural range as a 'nut' crop (notably in Hawaii, where it is the principal orchard crop). We sampled seven DNA regions and 53 morphological characters from the tribe to infer its phylogeny and address the common assumption that the distribution of the extant diversity of the tribe arose by the rafting of ancestors on Gondwanan fragments. Macadamia proves to be paraphyletic with respect to the African genus Brabejum, the South American genus Panopsis, and the Australian species Orites megacarpus. We erect two new generic names, Nothorites and Lasjia, to produce monophyly at that rank. The earliest disjunctions in the tribe are inferred to be the result of long-distance dispersal out of Australia (with one possible exception), rather than vicariance. Evolution of tardy fruit dehiscence is correlated with these dispersals, and the onset of the Antarctic Circumpolar Current (ACC) precedes them. We suggest that the ancestors of extant diversity arrived on their respective continents via the ACC, and we recognize that this is a mechanism precluded, rather than facilitated, by Gondwana's terrestrial continuity. Key words: biogeography; fruit evolution; Gondwana; hydrochory; long-distance dispersal; Macadamia; relaxed-clock molecular dating; phylogenetics; Proteaceae; vicariance.

Lysosomes are the stomachs of the cell--terminal organelles on the endocytic pathway where internalized macromolecules are degraded. Containing a wide range of hydrolytic enzymes, lysosomes depend on maintaining acidic luminal [...]

It is shown that pulse-height spectra acquired from a high-pressure Xe +[sup.3]He gas ionization chamber exposed to mixed gamma-neutron radiation fields can be unfolded into separate gamma ray and thermal neutron spectra. The procedure takes advantage of the unique shape of the recently discovered spectral response of thermal neutrons in this high pressure Xe +[sup.3]He mixture. A template spectrum formed from only the pulse-height distribution of neutron signals is subtracted from the combined gamma and neutron spectrum to provide an estimate for the count of thermal neutrons. This procedure leaves a pure gamma spectrum for standard gamma ray spectrum analyses and isotope identification. Index Terms--Gamma rays, high-pressure gas ionization chamber, identification nuclear materials, pulse height spectrum, thermal neutrons, Xe +[sup.3]He.

The dairy farmers in Vermont's Champlain Valley were surveyed to assess present hayfield management practices and farmers' willingness to adopt more bird-friendly practices. An extension and education efforts target farmers with large hayfield acreages, encouraging the maintenance of high-quality habitat for grassland songbirds.

We sequenced seven cpDNA regions from 70 spp. in Dodecatheon, Primula subgenus Auriculastrum, and outgroups, reconstructed their cpDNA phylogeny with maximum parsimony, and determined branch support with bootstrap frequencies and Bayesian posterior probabilities. Strongly supported conclusions include the (1) paraphyly of Primula subgenus Auriculastrum with respect to a monophyletic Dodecatheon, (2) sister relationship between the North American Dodecatheon and the Californian P. suffrutescens, (3) novel basal split in Dodecatheon to produce one clade with rugose and one clade with smooth anther connectives, (4) monophyly of all sections of Primula subgenus Auriculastrum, and (5) exclusion of the enigmatic Primula section Amethystina from the similar Primula subgenus Auriculastrum. These results support the origin of the monomorphic, buzz-pollinated flower of Dodecatheon from the heterostylous flower of Primula. We marshal evidence to support the novel hypothesis that the solanoid flower of Dodecatheon represents the fixation of recessive alleles at the heterostyly linkage group (pin phenotype). Of the remaining traits associated with their solanoid flowers, we recognize at least six likely to have arisen with the origin of Dodecatheon, one that preceded it (flower coloration, a transfer exaptation in Dodecatheon), and one that followed it (rugose anther connectives, an adaptation to buzz pollination). Key words: adaptation; buzz pollination; Cortusa; Dodecatheon; exaptation; heterostyly; Primula subgenus Auriculastrum; solanoid flowers.

Banksia and Dryandra have undergone extensive speciation and adaptive radiation, especially in Australia's isolated Southwest Botanical Province. We derive a phylogeny for these groups based on cpDNA sequences and use it to reconstruct their historical biogeography and evolution of leaf traits thought to be adapted to drought and/or nutrient poverty. Slowly evolving regions (trnL intron, trnL/trnF spacer) are used to resolve large-scale relationships; faster evolving regions (rp116 intron, psbA/trnH and trnT/trnL spacers) are used to resolve relationships among closely related species. Banksia is paraphyletic with respect to Dryandra. The lineage underwent a basal split into two clades (here named/Cryptostomata and/Phanerostomata), and four infrageneric taxa supported by morphological cladistic analyses (series Spicigerae, Abietinae, Tetragonae, and Banksia) are not monophyletic. Dispersal-vicariance analysis resolves a southwestern Australian origin for the lineage, with two later expansions to the east followed by vicariance events. Stomatal crypts arose with the /Cryptostomata, which is characterized by tough, long-lived leaves and common in southwestern Australia. Sequestering of stomata also arose multiple times in /Phanerostomata, which is characterized by softer, short-lived leaves and common in moister coastal areas, via inrolling of the margins of narrow leaves and restricting stomata to shallow pits. The hypothesis that sclerophylly preadapted the plants to xeromorphy is supported in the case of shallow stomatal pits and deep stomatal crypts, but not narrow, needle-like leaves. Key words: Australia's Southwest Botanical Province; Banksia; Dryandra; historical biogeography; molecular systematics; preadaptation; sclerophylly; xeromorphy.