6,542 research outputs found
Structure-function relations in phosphorylcholine-binding mouse myeloma proteins
The binding site interactions between the phosphorylcholine (phosphocholine)-binding mouse myeloma proteins TEPC 15, W3207, McPC 603, MOPC 167, and MOPC 511 and the isotopically substituted hapten phosphoryl-[methyl-13C]choline have been investigated using 13C and 31P nuclear magnetic resonance (NMR) spectroscopy. Each protein exhibits a unique NMR pattern, but extensive similarities in chemical shift parameters upon binding of hapten to immunoglobulin suggest a significant degree of conservation of important hapten-binding site interactions. Moreover, independent binding studies, in conjunction with the NMR data, allow construction of a simple model of the binding sites of these antibodies, analyzed in terms of the relative strength of interaction between hapten and two main subsites. The NMR evidence supports the view that the heavy chains of these proteins dominate in interacting with bound phosphorylcholine; the various subspecificities of these proteins for phosphorylcholine analogues can be accounted for by amino acid changes in the hypervariable regions of the heavy chains
An Analysis of Structural and Psychological Barriers to the Adoption of Demand Response Smart Grid Technologies: Lessons Learned
Over the past decade, America’s utility grid has undergone fundamental changes on a scale not seen during the past 100 years (Energetics Incorporated, 2014). These changes have largely been driven by the need to replace aging infrastructure, modernize the grid, incorporate new sources of energy, and better balance the supply and demand of energy. In order to address some of these changes, utilities have increasingly implemented smart grid programs that provide customers with consumer-focused demand response technologies that aim to reduce peak demand. This report examined the success these technologies have in reducing peak demand for smart grid programs by utilizing National Grid’s Smart Energy Solutions (SES) program as a case study and drawing on learnings from other smart grid programs. By using benchmarking and a hierarchy of effects marketing analysis, structural and psychological barriers to customer adoption of these technologies were identified and National Grid was provided with six recommendations for overcoming these barriers to increase technology adoption and reduce peak demand
Direct and indirect selection on flowering time, water-use efficiency (WUE, δ (13)C), and WUE plasticity to drought in Arabidopsis thaliana.
Flowering time and water-use efficiency (WUE) are two ecological traits that are important for plant drought response. To understand the evolutionary significance of natural genetic variation in flowering time, WUE, and WUE plasticity to drought in Arabidopsis thaliana, we addressed the following questions: (1) How are ecophysiological traits genetically correlated within and between different soil moisture environments? (2) Does terminal drought select for early flowering and drought escape? (3) Is WUE plasticity to drought adaptive and/or costly? We measured a suite of ecophysiological and reproductive traits on 234 spring flowering accessions of A. thaliana grown in well-watered and season-ending soil drying treatments, and quantified patterns of genetic variation, correlation, and selection within each treatment. WUE and flowering time were consistently positively genetically correlated. WUE was correlated with WUE plasticity, but the direction changed between treatments. Selection generally favored early flowering and low WUE, with drought favoring earlier flowering significantly more than well-watered conditions. Selection for lower WUE was marginally stronger under drought. There were no net fitness costs of WUE plasticity. WUE plasticity (per se) was globally neutral, but locally favored under drought. Strong genetic correlation between WUE and flowering time may facilitate the evolution of drought escape, or constrain independent evolution of these traits. Terminal drought favored drought escape in these spring flowering accessions of A. thaliana. WUE plasticity may be favored over completely fixed development in environments with periodic drought
Outer-Sphere Effects on Reduction Potentials of Copper Sites in Proteins: The Curious Case of High Potential Type 2 C112D/M121E Pseudomonas aeruginosa Azurin
Redox and spectroscopic (electronic absorption, multifrequency electron paramagnetic resonance (EPR), and X-ray absorption) properties together with X-ray crystal structures are reported for the type 2 Cu^(II) C112D/M121E variant of Pseudomonas aeruginosa azurin. The results suggest that Cu^(II) is constrained from interaction with the proximal glutamate; this structural frustration implies a “rack” mechanism for the 290 mV (vs NHE) reduction potential measured at neutral pH. At high pH (~9), hydrogen bonding in the outer coordination sphere is perturbed to allow axial glutamate ligation to Cu^(II), with a decrease in potential to 119 mV. These results highlight the role played by outer-sphere interactions, and the structural constraints they impose, in determining the redox behavior of transition metal protein cofactors
High-Potential C112D/M121X (X = M, E, H, L) Pseudomonas aeruginosa Azurins
Site-directed mutagenesis of Pseudomonas aeruginosa azurin
C112D at the M121 position has afforded a series of proteins with
elevated Cu^(II/I) reduction potentials relative to the CuII aquo ion.
The high potential and low axial hyperfine splitting (Cu^(II) electron
paramagnetic resonance A|) of the C112D/M121L protein are
remarkably similar to features normally associated with type 1
copper centers
Childhood reading problems and cognitive ageing across mid to later life
BACKGROUND: Little research has investigated long-term associations of childhood reading with cognitive ageing. The aim of this study was to test longitudinal associations between childhood reading problems and cognitive function from mid-adulthood (age 43) to early old age (age 69), and whether associations were mediated by education. METHODS: Data were from the MRC National Survey of Health and Development, a prospective population-based birth cohort. Reading problems were measured at age 11 using a reading test. Verbal memory and processing speed were measured at ages 43, 53, 60-64 and 69 and Addenbrooke's Cognitive Examination (ACE) was administered at age 69. Linear mixed models and path analyses were used to test: (1) associations between reading problems and verbal memory and processing speed trajectories; (2) associations between reading problems and ACE-III scores; (3) whether associations were mediated by education. RESULTS: Reading problems were associated with poorer verbal memory at intercept but not rate of decline (N=1726), and were not associated with processing speed intercept or decline (N=1730). There were higher rates of scores below ACE-III clinical thresholds (<82 and <88) in people with reading problems compared with those without. Reading problems were associated with poorer total ACE-III scores and all domain scores at age 69 (N=1699). Associations were partly mediated by education. CONCLUSION: Reading problems in childhood were associated with poorer cognitive function in early old age, and associations were partly mediated by education
Upper Rio Grande Valley - Texas Interindustry Study
The Interindustry Study of the Upper Rio Grande Valley indicates that the region is highly dependent on Federal government expenditures and export trade. The export-base industry in the region is highly dependent on imports and mostly related to outside firms. The manufacturing sector is quite limited to very few basic industries like primary metal, petroleum refining and apparels. These 3 industries have very low multipliers because the local supportive industry is not developed enough to provide the basic industries with a significant proportion of their input needs. The agricultural sector and the trades sector based on agricultural products have the highest multipliers among all local processing sectors because of their high dependence on local markets for their inputs. Unfortunately, their contribution to the gross regional product is minute because of their low level of output. These sectors should be encouraged to expand. The construction sections rank very high in the level of their outputs and their multipliers. However, they are highly dependent on government expenditures. A boom in regional construction will be quite helpful to the region insofar as most local processing sectors will be substantially affected by a rise in final demand for construction. The study shows that the regional processing sectors produced in 1967 an output valued at 692 million but imported goods and services valued at $730 million
Bidirectional relation between affective symptoms and cognitive function from middle to late adulthood: a population-based birth cohort study
Objectives: There is an association between affective symptoms and cognition. However, the direction of this association remains unclear. This study aimed to test bidirectional relationships between affective symptoms and cognition from middle to late adulthood.Method: Data were available from the MRC National Survey of Health and Development (NSHD), a prospective birth cohort of 5362 people born in 1946. Affective symptoms and cognition were measured at ages 53, 60-64, and 69. Latent scores of affective symptoms were derived and cross-lagged models were fitted for affective symptoms with verbal memory and processing speed. Results: Results revealed an inverse cross-sectional association between affective symptoms and verbal memory (β=-0.18, SE=0.04, p<.001) and processing speed (β=-0.13, SE=0.06, p=.05) at age 53, but not at ages 60-64 or 69. Affective symptoms at age 53 predicted lower verbal memory at age 60-64 (β=-0.58, SE=0.27, p=.03), and affective symptoms at age 60-64 predicted lower verbal memory (β=-0.64, SE=0.29, p=.03) and processing speed (β=-1.27, SE=0.41, p=.002) at age 69. Verbal memory and processing speed did not predict subsequent affective symptoms.Conclusion: Affective symptoms predict poorer verbal memory and processing speed over a period of 16 years, but not vice versa
Effect of an agri-environmental measure on nitrate leaching from a beef farming system in Ireland
peer-reviewedAgricultural nitrogen (N) management remains a key environmental challenge. Improving N management is a matter of urgency to reduce the serious ecological consequences of the reactive N. Nitrate (NO3−–N) leaching was measured under suckler beef production systems stocked at two intensities: (1) intensive, 210 kg organic N ha−1 with two cut silage harvests; and (2) rural environmental protection scheme (REPS), 170 kg organic N ha−1 with one cut silage harvest. Three replicate plots of each treatment were instrumented with ceramic cups (8 per plot), randomly placed within each plot at a depth of 1 m to collect soil solution for NO3−–N at 50 kPa suction to collecting vessels one week prior to sampling. Samples were taken on a total of 53 sampling dates over 3 winter drainage periods (2002/03, 2003/04 and 2004/05). Over the course of the experiment the mean annual soil solution NO3−–N concentration exceeded the MAC twice out of 15 means (5 treatments over 3 years). The REPS grazing and silage sub treatments had significantly lower mean annual soil solution total oxidized N (TON) concentrations than the respective intensive treatments in years 2 and 3. Annual total NO3−–N losses over the three years in intensive and REPS systems ranged from 55 to 71 and 15 to 20 kg N ha−1, respectively. Mean N surpluses in intensive and REPS systems were 210 and 95 kg ha−1, respectively with the corresponding mean N inputs of 272 and 124 kg N ha−1. The reduction in N inputs under the REPS system results in lower N leaching losses and contributed to a significant reduction in pressures on water quality
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