Voltage Sensing Mechanism in the Voltage-gated and Proton (H+)-selective Ion Channel Hv1

Activation of the intrinsic aqueous water-wire proton conductance (GAQ) in Hv1 channels is controlled by changes in membrane potential and the transmembrane pH gradient (ΔpH). The mechanism by which changes in ΔpH affect the apparent voltage dependence of GAQ activation is not understood. In order to measure voltage sensor (VS) activation in Hv1, we mutated a conserved Arg residue in the fourth helical segment (S4) to His and measured H+ currents under whole-cell voltage clamp in transfected HEK-293 cells. Consistent with previous studies in VS domain containing proteins, we find that Hv1 R205H mediates a robust resting-state H+ ‘shuttle’ conductance (GSH) at negative membrane potentials. Voltage-dependent GSH gating is measured at more negative voltages than the activation GAQ, indicating that VS activation is thermodynamically distinct from opening of the intrinsic H+ permeation pathway. A hallmark biophysical feature of Hv1 channels is a ~-40 mV/pH unit shift in the apparent voltage dependence of GAQ gating. We show here that changes pHO are sufficient to cause similar shifts in GSH gating, indicating that GAQ inherits its pH dependence from an early step in the Hv1 activation pathway. Furthermore, we show for the first time that Hv1 channels manifest a form of electromechanical coupling VS activation and GAQ pore opening. Second-site mutations of D185 markedly alter GAQ gating without affecting GSH gating, indicating that D185 is required for a late step in the activation pathway that controls opening of the aqueous H+ permeation pathway. In summary, this work demonstrates that the Hv1 activation pathway contains multiple transitions with distinct voltage and pH dependencies that have not been previously identified. The results reported here novel insight into the mechanism of VS activation in Hv1 and raise fundamental questions about the nature of pH-dependent gating and electromechanical coupling in related VS domain-containing ion channels and phosphatases

Key Technology, Programmatic Drivers, and Lessons Learned for Production of Proliferated Small Satellite Constellations

Proliferated small satellites are a critical element of achieving a more capable and resilient space enterprise vision. Current game-changing initiatives across the U.S. government seek to achieve robust, agile capabilities inherent with large-scale constellations and to leverage the significant investments being made in the commercial sector. Production scale and pace are critical elements for affordability. A measured balance between modularity, autonomy, rightsized verification concepts, and rigorous supply chain management permits rapid, cost effective mission deployments. Maxar (formerly Space Systems Loral), has gained unique insights to key production methods and lessons learned to enable these capabilities from several active programs, including delivery of nearly 20 SkySat-C spacecraft to Planet, development of Maxar’s WorldView Legion imaging constellation for launch in 2021, and preliminary efforts on Telesat’s LEO 200+ satellite communications constellation. In this paper, we will provide metrics from these programs along with discussion about derived insights, as well as recommendations for how the community should continue to evolve to meet the stringent performance and affordability thresholds required to achieve a resilient proliferated LEO vision

Aerial Inventories of Waterfowl in Illinois and Estimation of Moist-soil Plant Seed Abundance for Waterfowl on Lands Managed by Illinois Department of Natural Resources

Grant/Contract No: W-43-R 53-54-55Reports on progress and results of inventories of waterfowl along the Illinois and central Mississippi rivers during fall and winter and estimation of moist-soil plant seed abundance for waterfowl on lands managed by Illinois Department of Natural ResourcesINHS Technical Report Prepared for U.S. Fish & Wildlife Service, Illinois Department of Natural Resource

Commercial assessment of roll to roll manufacturing of electronic displays

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2006.Includes bibliographical references (leaves 76-81).The cost of manufacturing electronic displays currently limits the range of applications and markets into which it is currently economically feasible to adopt displays. Roll-to-roll manufacturing has been identified by the display industry as a new and fundamentally different manufacturing paradigm that has the potential to significantly reduce the manufacturing cost of a display relative to the conventional approaches used in the industry. This manufacturing cost reduction could have a profound impact on the display industry by not only transforming the display manufacturing infrastructure, but also by permitting electronic displays to penetrate new markets. The purpose of this thesis is to determine how roll-to-roll manufacturing technology could develop and to assess what impact the technology could have on the electronic display manufacturing industry. This work first identifies the material, patterning, and equipment technologies that need to come together in order for roll-to-roll manufacturing to be industrially feasible, and then determines how and if the technology will offer a cost reduction over conventional manufacturing techniques.(cont.) Next, the markets for displays are segmented and analyzed to discern whether niche initial markets exist where roll-to-roll could have a distinctive advantage and gain traction. Competitive technologies such as LCD and modular LED are discussed and it is determined that roll-to-roll displays must compete with LCD technology on the basis of price in the markets in which LCD has incumbency in order to achieve widespread adoption. The display industry structure is analyzed by means of an assessment of the supply chain, intellectual property landscape, financing mechanisms, and business models to understand how partnerships and financial investment risk are salient aspects of the commercialization process. It is concluded that materials cost advantages over current manufacturing approaches and the timing of roll-to-roll technology integration developments relative to the incremental manufacturing cost decreases in competing technologies will ultimately dictate the success of roll-to-roll manufacturing.by Michael Aaron Randolph.M.Eng

Graphic Presentation: An Empirical Examination of the Graphic Novel Approach to Communicate Business Concepts

Graphic novels have been increasingly incorporated into business communication forums. Despite potential benefits, little research has examined the merits of the graphic novel approach. In response, we engage in a two-study approach. Study 1 explores the potential of graphic novels to affect learning outcomes and finds that the graphic novel was related to high levels of learning experiences. Study 2 compares the impact of graphic novels with that of traditional textbooks and finds that verbatim recognition was superior with graphic novel texts. Overall, we provide the first comprehensive examination of the graphic novel as a tool for effective business communication.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Predictive Modeling of Fast-Curing Thermosets in Nozzle-Based Extrusion

This work presents an approach to modeling the dynamic spreading and curing behavior of thermosets in nozzle-based extrusions. Thermosets cover a wide range of materials, some of which permit low-temperature processing with subsequent high-temperature and high-strength working properties. Extruding thermosets may overcome the limited working temperatures and strengths of conventional thermoplastic materials used in additive manufacturing. This project aims to produce technology for the fabrication of thermoset-based structures leveraging advances made in nozzle-based extrusion, such as fused deposition modeling (FDM), material jetting, and direct writing. Understanding the synergistic interactions between spreading and fast curing of extruded thermosetting materials will provide essential insights for applications that require accurate dimensional controls, such as additive manufacturing [1], [2] and centrifugal coating/forming [3]. Two types of thermally curing thermosets -- one being a soft silicone (Ecoflex 0050) and the other being a toughened epoxy (G/Flex) -- served as the test materials in this work to obtain models for cure kinetics and viscosity. The developed models align with extensive measurements made with differential scanning calorimetry (DSC) and rheology. DSC monitors the change in the heat of reaction, which reflects the rate and degree of cure at different crosslinking stages. Rheology measures the change in complex viscosity, shear moduli, yield stress, and other properties dictated by chemical composition. By combining DSC and rheological measurements, it is possible to establish a set of models profiling the cure kinetics and chemorheology without prior knowledge of chemical composition, which is usually necessary for sophisticated mechanistic modeling. In this work, we conducted both isothermal and dynamic measurements with both DSC and rheology. With the developed models, numerical simulations yielded predictions of diameter and height of droplets, along with width and height of extruded lines cured at varied temperatures. Experimental results carried out on a goniometric platform and a nozzle-based 3D printer showed agreement with the numerical simulations. Finally, this presentation will show how the models are adaptable to the planning of tool paths and designs in additive manufacturing

Waterbird and Wetland Monitoring at The Emiquon Preserve Final Report 2007-2009

We monitored the response of wetland habitats and waterbirds to restoration efforts at Emiquon during 2007–2010 to evaluate restoration success relative to desired conditions under the relevant key ecological attributes (KEAs). Our primary efforts included evaluating: 1) abundance, diversity, and behavior of waterfowl and other waterbirds through counts and observations; 2) productivity by waterfowl and other waterbirds through brood counts; 3) plant seed and invertebrate biomass to understand foraging carrying capacity for waterfowl during migration and breeding, and; 4) composition and arrangement of the vegetation community through geospatial wetland covermapping. Herein, we report results of our monitoring efforts and interpret them as a means of evaluating restoration activities at Emiquon with respect to desired conditions under the KEAs.The Nature Conservancy, Illinois River Project Office, contract number C07-032unpublishednot peer reviewedOpe

Seed Abundance for Waterfowl in Wetlands Managed by the Illinois Department of Natural Resources

Managed wetlands on public lands in Illinois, United States, provide foraging habitats for migrating and wintering waterfowl. However, few studies have estimated abundances of waterfowl foods in mid-migration regions of North America, yet such information is needed to inform management and conservation decision-making. During 2005– 2007, we used a multistage sampling design to estimate moist-soil plant seed production (kg/ha, dry mass) and energetic carrying capacity at sites managed by the Illinois Department of Natural Resources and modeled variation in seed biomass. Average seed biomass among all sites ranged from 1,030.0 6 64.1 (SE) kg/ha in 2005 to 501.5 6 124.1 kg/ha in 2007. Our overall estimate (2005–2007) of moist-soil plant seed biomass was precise (691.3 6 56.4 kg/ ha; CV: 8.2%), equaling 5,128 energetic use-days/ha. This value was similar to or slightly greater than previous estimates from other regions of North America and exceeded the estimate used the Upper Mississippi River and Great Lakes Region Joint Venture for waterfowl conservation planning (514 kg/ha). We formulated eight models to predict abundance of moist-soil plant seeds within sampled wetlands. The best approximating model included the number of desirable plant species within wetlands and study year. The second best model included the categorical effect of management intensity and indicated that, although variable, actively managed wetlands produced about 240 kg/ha more seed than those that were passively managed. As with other regions, wetland management practices that encourage diverse plant communities over monotypes and growth of early successional plants should yield substantial increases in waterfowl food abundances at Illinois Department of Natural Resources sites, especially given that only 27% of our study wetlands were actively managed. Such efforts would also help reduce deficits in energetic carrying capacity identified by the Upper Mississippi River and Great Lakes Region Joint Venture

Decoy peptide targeted to Toll-IL-1R domain inhibits LPS and TLR4-active metabolite morphine-3 glucuronide sensitization of sensory neurons

Accumulating evidence indicates that Toll-like receptor (TLR) signaling adapter protein interactions with Toll/Interleukin-1 Receptor (TIR) domains present in sensory neurons may modulate neuropathic pain states. Following ligand interaction with TLRs, TIR serves to both initiate intracellular signaling and facilitate recruitment of signaling adapter proteins to the intracytoplasmic domain. Although TLR TIR is central to a number of TLR signaling cascades, its role in sensory neurons is poorly understood. In this study we investigated the degree to which TLR TIR decoy peptide modified to include a TAT sequence (Trans-Activator of Transcription gene in HIV; TAT-4BB) affected LPS-induced intracellular calcium flux and excitation in sensory neurons, and behavioral changes due to TLR4 active metabolite, morphine-3-glucuronide (M3G) exposure in vivo. TAT-4BB inhibited LPS-induced calcium changes in a majority of sensory neurons and decreased LPS-dependent neuronal excitability in small diameter neurons. Acute systemic administration of the TAT-4BB reversed M3G-induced tactile allodynia in a dose-dependent manner but did not affect motor activity, anxiety or responses to noxious thermal stimulus. These data suggest that targeting TLR TIR domains may provide novel pharmacological targets to reduce or reverse TLR4-dependent pain behavior in the rodent

Foraging Ecology of Fall-Migrating Shorebirds in the Illinois River Valley

Populations of many shorebird species appear to be declining in North America, and food resources at stopover habitats may limit migratory bird populations. We investigated body condition of, and foraging habitat and diet selection by 4 species of shorebirds in the central Illinois River valley during fall migrations 2007 and 2008 (Killdeer [Charadrius vociferus], Least Sandpiper [Calidris minutilla], Pectoral Sandpiper [Calidris melanotos], and Lesser Yellowlegs [Tringa flavipes]). All species except Killdeer were in good to excellent condition, based on size-corrected body mass and fat scores. Shorebird diets were dominated by invertebrate taxa from Orders Diptera and Coleoptera. Additionally, Isopoda, Hemiptera, Hirudinea, Nematoda, and Cyprinodontiformes contribution to diets varied by shorebird species and year. We evaluated diet and foraging habitat selection by comparing aggregate percent dry mass of food items in shorebird diets and core samples from foraging substrates. Invertebrate abundances at shorebird collection sites and random sites were generally similar, indicating that birds did not select foraging patches within wetlands based on invertebrate abundance. Conversely, we found considerable evidence for selection of some diet items within particular foraging sites, and consistent avoidance of Oligochaeta. We suspect the diet selectivity we observed was a function of overall invertebrate biomass (51.264.4 [SE] kg/ha; dry mass) at our study sites, which was greater than estimates reported in most other food selection studies. Diet selectivity in shorebirds may follow tenants of optimal foraging theory; that is, at low food abundances shorebirds forage opportunistically, with the likelihood of selectivity increasing as food availability increases. Nonetheless, relationships between the abundance, availability, and consumption of Oligochaetes for and by waterbirds should be the focus of future research, because estimates of foraging carrying capacity would need to be revised downward if Oligochaetes are truly avoided or unavailable for consumption