Why is Asp-286 conserved in the V-ATPase? : an honors thesis (HONRS 499)

V-ATPases are multi-subunit proton pumps found on the cellular membranes of most organisms from yeast (Saccharomyces cerviseae) to humans. They are composed of two main components capable of reversible disassembly: V1 and V0. VI is composed of eight different subunits and is the peripheral domain, whereas Vo is composed of five different subunits and is the integral domain. The long-term objective of this research is to determine the function of one of these subunits on the V. complex: subunit d, encoded by the VMA6 gene. Subunit d is of interest because it serves as the bridge between V I and Vo.Asp-286 of subunit d is highly conserved in mammals, insects and fungi, suggesting that it may be important for V-ATPase function. Using QuikChange site-directed mutagenesis by PCR, a mutation was introduced in subunit d. The mutation substituted aspartic acid on position 286 with alanine. We hypothesized that if Asp-286 has a structural role in subunit d, this change would modify the tertiary structure of subunit d and possibly alter the activity and assembly of the V-ATPase complex.Honors CollegeThesis (B.?.

Characterization of The Heat Transfer on Spray Quenching for Different Material Properties

A broad range of water spray applications as a means of two-phase cooling scheme has encouraged researches in the thermal management system to support safety and process efficiency in industries. In the application of above saturation temperature, the cooling process follows the boiling curve where the dissipated heat flux is figured out as a function of the wall temperature. Knowledge on constructing the boiling curve is an essential part in order to define the moving boundary, and boundary value problems occur in metal cooling process analysis involving heat transfer and phase change. The objective of the research was to characterize the boiling parameters on different materials in the regime of film boiling, transition boiling, and nucleate boiling as the basis for its boiling curve construction. To explain the influence of material properties, this work is featuring, firstly, the calculated vapor film thickness in film boiling regime by promoting self-developed analytical model of single droplet and, secondly, the calculated boiling width which indicates a strong combination of surface temperature and heat flux observed as the boiling phenomena. This is obtained by calculating the propagation of wetting front and 100 oC points. This experimental work employed a volumetric spray flux of 4.2, 10 and 13.7 kg/m2s to cool a hot metal samples of aluminum alloy AA6082 and nickel heated up to 560 °C. An infrared camera was used to record the temperature drop over time. Heat flux calculation follows the numerical procedure according to 1D energy balance model. Calculated vapor film thickness explains why the HTC tends to increase with the decrease of the surface temperature. Leidenfrost and Departure from Nucleate Boiling (DNB) temperatures are found to be inversely proportional to the heat penetration coefficient of the metal while maximum heat flux and boiling width increase with it

Tweeting with Authority: Identifying Influential Participants in Agriculture-Related Water Quality Twitter Conversations

In August 2014, Toledo, Ohio, experienced a dangerous algae bloom that led to a citywide water ban. News media coverage of the incident was widespread, as was social media conversation. Opinion leadership has been linked to news media agenda setting, and social media users are capable of generating considerable social influence within the sphere of their social networks. To better understand the dynamics of the conversation—especially as it pertained to agriculture—both during and after the water ban, the researchers used a social media analysis platform to identify high-influence Twitter users who participated in water-quality discussions about the Toledo water ban. Narrowing the search to agriculture-related discussion, the researchers revealed a dearth of agriculture-related content and also identified three categories of Twitter users in the conversation, including news sources, activists, and agriculture advocates. The researchers also found that Ohio users in post-ban discussions tended to be more influential than those who participated during the water ban. Identifying these users allows practitioners to monitor influential accounts for emerging issues and to engage with authoritative users in their geographic regions. The researchers also recommend that agriculture advocates exercise restraint in publicly speaking out about the industry’s involvement in environmental issues

Research Notes: Evaluation of some soybean isolines in irrigation culture

About 9% of the total soybean acreage and about 50% of the total corn acreage in Nebraska was irrigated at least once during the growing season in 1975. The 1975 state averages for irrigated soybeans and irrigated corn were 2220 and 7605 kg/ha respectively. Obviously, this yield differential (in relation to the price and production cost differentials) accounts for the reason most farmers utilize their irrigated acreage for corn rather than soybeans

A nanoflare model for active region radiance: application of artificial neural networks

Context. Nanoflares are small impulsive bursts of energy that blend with and possibly make up much of the solar background emission. Determining their frequency and energy input is central to understanding the heating of the solar corona. One method is to extrapolate the energy frequency distribution of larger individually observed flares to lower energies. Only if the power law exponent is greater than 2, is it considered possible that nanoflares contribute significantly to the energy input. Aims. Time sequences of ultraviolet line radiances observed in the corona of an active region are modelled with the aim of determining the power law exponent of the nanoflare energy distribution. Methods. A simple nanoflare model based on three key parameters (the flare rate, the flare duration time, and the power law exponent of the flare energy frequency distribution) is used to simulate emission line radiances from the ions Fe XIX, Ca XIII, and Si iii, observed by SUMER in the corona of an active region as it rotates around the east limb of the Sun. Light curve pattern recognition by an Artificial Neural Network (ANN) scheme is used to determine the values. Results. The power law exponents, alpha 2.8, 2.8, and 2.6 for Fe XIX, Ca XIII, and Si iii respectively. Conclusions. The light curve simulations imply a power law exponent greater than the critical value of 2 for all ion species. This implies that if the energy of flare-like events is extrapolated to low energies, nanoflares could provide a significant contribution to the heating of active region coronae.Comment: 4 pages, 5 figure

Local texture and percolative paths for long-range conduction in high critical current density TlBa₂Ca₂Cu₃O₈₊ₓ deposits

©1994 American Institute of Physics. The electronic version of this article is the complete one and can be found online at: http://link.aip.org/link/?APPLAB/64/106/1DOI:10.1063/1.110908A possible microstructural origin of the high critical current densities which have been obtained in c-axis-aligned, polycrystalline TlBa₂Ca₂Cu₃O₈₊ₓdeposits has been identified. The results of x-ray diffraction determinations of basal plane texture of Tl-1223 deposits prepared by spray pyrolysis are observed to depend on the size of the x-ray beam. Furthermore, most grain boundaries were found from transmission electron microscopy to have small misorientation angles. It is concluded that although overall the basal plane orientations are nearly random, there is a high degree of local texture indicative of colonies of similarly oriented grains. The spread in a-axis orientation within a colony is ~10°–15°. Intercolony conduction, it is suggested, may be enhanced by a percolative network of small-angle grain boundaries at colony interfaces

On the existence of a generalized non-specific task-dependent network

In this paper we suggest the existence of a generalized task-related cortical network that is up-regulated whenever the task to be performed requires the allocation of generalized non-specific cognitive resources, independent of the specifics of the task to be performed. We have labeled this general purpose network, the extrinsic mode network (EMN) as complementary to the default mode network (DMN), such that the EMN is down-regulated during periods of task-absence, when the DMN is up-regulated, and vice versa. We conceptualize the EMN as a cortical network for extrinsic neuronal activity, similar to the DMN as being a cortical network for intrinsic neuronal activity. The EMN has essentially a fronto-temporo-parietal spatial distribution, including the inferior and middle frontal gyri, inferior parietal lobule, supplementary motor area, inferior temporal gyrus. We hypothesize that this network is always active regardless of the cognitive task being performed. We further suggest that failure of network up- and down-regulation dynamics may provide neuronal underpinnings for cognitive impairments seen in many mental disorders, such as, e.g., schizophrenia. We start by describing a common observation in functional imaging, the close overlap in fronto-parietal activations in healthy individuals to tasks that denote very different cognitive processes. We now suggest that this is because the brain utilizes the EMN network as a generalized response to tasks that exceeds a cognitive demand threshold and/or requires the processing of novel information. We further discuss how the EMN is related to the DMN, and how a network for extrinsic activity is related to a network for intrinsic activity. Finally, we discuss whether the EMN and DMN networks interact in a common single brain system, rather than being two separate and independent brain systems

Where I Come From: Exploring Regional Differences in California Consumers’ Attitudes and Beliefs About Fluid Milk

Guided by the theory of reasoned action and social cognitive theory, this study was conducted to better understand how decisions to purchase organic or conventional milk are influenced by norms and attitudes established via human interactions and how those norms and attitudes vary by geographic region. An online Qualtrics survey was used to gain insight into behaviors, attitudes, and interactions of 308 milk consumers in various geographical regions of [State]. The findings indicate that urban, suburban, and rural consumers differ in some ways in their interactions related to milk information, as well as their perceptions of organic versus conventional milk. Based on the findings of the study, differences in personal networks and exposure to certain messaging in varying regions might perpetuate a more positive, confident, and informed view of organic or conventional milk products in some areas more so than others. The researchers recommend using the results of the study to tailor messages to the specific information needs of consumers in urban, suburban, and rural regions of [State]

Game based lifelong learning

Kelle, S., Sigurðarson, S., Westera, W., & Specht, M. (2011). Game-Based Life-Long Learning. In G. D. Magoulas (Ed.), E-Infrastructures and Technologies for Lifelong Learning: Next Generation Environments (pp. 337-349). Hershey, PA: IGI Global.Digital Games as a means of learning have become more important in recent years. Infrastructural and sociological developments have created fertile grounds for game innovations, making use of latest technology and being welcomed by new generations of learners. This chapter focuses on an overview of the current state of the art of learning games, explaining different perspectives. As the gamers’ generation has now grown up, the educational contexts for life-long learning like higher and vocational education are moving into the scope of game based learning and therefore deserve special attention

Study of Coronavirus Protease Using CFP-YFP Fluorescent Assay

Middle Eastern Respiratory Syndrome (MERS) is an emerging viral disease originating in the Arabian Peninsula with a current mortality rate of nearly fifty percent throughout Europe and Asia according to the World Health Organization. Characterization of this disease is being done to understand the basis of viral replication. One target for viral inhibition are replication proteases. Replication proteases are enzymes that cleave proteins specific to cell growth and reproduction that form the viral replicase complex making them an ideal target for viral replication inhibition. First, replication proteases were characterized using a fluorescence resonance energy transfer (FRET) construct by measuring the amount of fluorescence emitted during enzymatic activity. This construct produces a measurable change in fluorescent activity to analyze the rate at which replication proteases cleave proteins essential for viral growth. Once this assay was completed, data was extracted and enzymatic kinetic calculations were performed to continue further analysis of enzymatic activity. The results produced from these experiments will allow a comparison of replication proteases specific to MERS with other viral replication proteases. Further analysis will be done to measure varying cleavage rates of different coronaviruses. This study produces conclusive results for the characterization of MERS replication proteases that are essential in further development of inhibitor molecules