Insights into antibody catalysis: Structure of an oxygenation catalyst at 1.9-Å resolution

The x-ray crystal structures of the sulfide oxidase antibody 28B4 and of antibody 28B4 complexed with hapten have been solved at 2.2-Å and 1.9-Å resolution, respectively. To our knowledge, these structures are the highest resolution catalytic antibody structures to date and provide insight into the molecular mechanism of this antibody-catalyzed monooxygenation reaction. Specifically, the data suggest that entropic restriction plays a fundamental role in catalysis through the precise alignment of the thioether substrate and oxidant. The antibody active site also stabilizes developing charge on both sulfur and periodate in the transition state via cation-pi and electrostatic interactions, respectively. In addition to demonstrating that the active site of antibody 28B4 does indeed reflect the mechanistic information programmed in the aminophosphonic acid hapten, these high-resolution structures provide a basis for enhancing turnover rates through mutagenesis and improved hapten design

Growth in young children with homozygous sickle cell disease

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Accretion Disk Temperatures of QSOs: Constraints from the Emission Lines

QSO emission-line spectra are compared to predictions based on theoretical ionizing continua of accretion disks. Observed line intensities do not show the expected trend of higher ionization with higher accretion disk temperature as derived from the black hole mass and accretion rate. This suggests that, at least for accretion rates close to the Eddington limit, the inner disk does not reach temperatures as high as expected from standard disk theory. Modified radial temperature profiles, taking account of winds or advection in the inner disk, achieve better agreement with observation. This conclusion agrees with an earlier study of QSO continuum colors as a function of disk temperature. The emission lines of radio-detected and radio-undetected sources show different trends as a function of disk temperature.Comment: 9 pages, 8 figures, submitted to Ap

Characterizing HV XLPE cables by electrical, chemical and microstructural measurements on cable peeling: Effects of surface roughness, thermal treatment and peeling location

Characterization of the electrical, chemical, and microstructural properties of high voltage cables was the first step of the European project “ARTEMIS”, which has the aim of investigating degradation processes and constructing aging models for the diagnosis of cross-linked polyethylene (XLPE) cables. Cables produced by two different manufacturers were subjected to a large number of electrical, microstructural, and chemical characterizations, using cable peelings, instead of lengths of whole cables, as specimens for the measurements. Here the effect of surface deformation and roughness due to peeling and the relevance and significance of thermal pre-treatment prior to electrical and other measurements is discussed. Special emphasis is put on space charge, conduction current and luminescence measurements. We also consider the dependence of these properties on the spatial position of the specimen within the cable. It is shown that even though the two faces of the cable peel specimens have different roughness, the low-field electrical properties seem quite insensitive to surface roughness, while significant differences are detectable at high fields. Thermal pre-treatment is required to stabilize the insulating material to enable us to obtain reproducible results and reliable inter-comparisons throughout the whole project. The spatial position of the specimens along the cable radius can also have a non-negligible influence on the measured properties, due to differential microstructure and chemical composition

Rural environmental concern: Effects of position, partisanship and place

The social bases of environmental concern in rural America resemble those for the nation as a whole, but also reflect the influence of place. Some general place characteristics, such as rates of population growth or resource-industry employment, predict responses across a number of environmental issues. Other unique or distinctive aspects of local society and environment matter as well. We extend earlier work on both kinds of place effects, first by analyzing survey data from northeast Oregon. Results emphasize that “environmental concern” has several dimensions. Second, we contextualize the Oregon results using surveys from other regions. Analysis of an integrated dataset (up to 12,000 interviews in 38 U.S. counties) shows effects from respondent characteristics and political views, and from county rates of population growth and resource-based employment. There also are significant place-to-place variations that are not explained by variables in the models. To understand some of these we return to the local scale. In northeast Oregon, residents describe how perceptions of fire danger from unmanaged forest lands shape their response to the word conservation. Their local interpretation contrasts with more general and urban connotations of this term, underlining the importance of place for understanding rural environmental concern

Electrometer system measures nanoamps at high voltage

Floating electrometer eliminates major source of error since any leakage from electrometer case, which is at high voltage, appears only as load on high voltage supply and not as part of current being measured. Commands to and data from floating electrometer are transferred across high voltage interface by means of optical channels

Modeling associations between public understanding, engagement and forest conditions in theInland Northwest, USA

Opinions about public lands and the actions of private non-industrial forest owners in the western United States play important roles in forested landscape management as both public and private forests face increasing risks from large wildfires, pests and disease. This work presents the responses from two surveys, a random-sample telephone survey of more than 1500 residents and a mail survey targeting owners of parcels with 10 or more acres of forest. These surveys were conducted in three counties (Wallowa, Union, and Baker) in northeast Oregon, USA. We analyze these survey data using structural equation models in order to assess how individual characteristics and understanding of forest management issues affect perceptions about forest conditions and risks associated with declining forest health on public lands. We test whether forest understanding is informed by background, beliefs, and experiences, and whether as an intervening variable it is associated with views about forest conditions on publicly managed forests. Individual background characteristics such as age, gender and county of residence have significant direct or indirect effects on our measurement of understanding. Controlling for background factors, we found that forest owners with higher self-assessed understanding, and more education about forest management, tend to hold more pessimistic views about forest conditions. Based on our results we argue that self-assessed understanding, interest in learning, and willingness to engage in extension activities together have leverage to affect perceptions about the risks posed by declining forest conditions on public lands, influence land owner actions, and affect support for public policies. These results also have broader implications for management of forested landscapes on public and private lands amidst changing demographics in rural communities across the Inland Northwest where migration may significantly alter the composition of forest owner goals, understanding, and support for various management actions