An antigenic polysaccharide from Campylobacter coli serotype O:30. Structure of a teichoic acid-like antigenic polysaccharide associated with the lipopolysaccharide

A water-soluble antigenic polysaccharide of high M(r) associated with the lipopolysaccharide has been isolated from phenol-water extraction of cells of Campylobacter coli serotype O:30. The polysaccharide and oligosaccharide degradation products formed on O-dephosphorylation and by periodate oxidation followed by reduction have been investigated by one- and two-dimensional 1H, 13C, and 31P NMR. It is concluded that the antigenic polysaccharide has a teichoic acid-like structure with a poly-Ribitol phosphate, [5-Ribitol-1-P]n, backbone with side chains at O-2 of O-(6-deoxy-beta-D-talo-heptopyranosyl)-(1-->4)-(2-acetylamino-2-deoxy-beta-D- glucopyranosyl) units. The structure is unusual in Gram-negative bacteria and is unique in possessing 6-deoxy-D-talo-heptose as a constituent sugar. Evidence for the relationship of the antigenic polysaccharide to the lipopolysaccharide of low M(r) is discussed.     

A single mild episode of subacute ruminal acidosis does not affect ruminal barrier function in the short term

Twenty-four German Merino sheep (72.3 ± 10.1 kg of body weight) were fed an all-hay diet and assigned to either the subacute ruminal acidosis (SARA) treatment (n = 17) or sham treatment (n = 7). The SARA sheep were orally dosed with a 2.2 M glucose solution to supply 5 g of glucose/kg of body weight, whereas sham sheep received an equal volume of water. Ruminal pH was measured for 48 h before and 3 h after the oral dose. Sheep were then killed and ruminal epithelia from the ventral sac were mounted in Ussing chambers. The serosal-to-mucosal flux rate of partially ³H-labeled mannitol (J_mannitol-SM), an indicator of barrier function, was measured while epithelia were exposed to 3 sequential in vitro measurement periods lasting 1 h each. The measurement periods consisted of baseline, challenge, and recovery periods and were interspersed by 30-min periods for treatment equilibration. Baseline conditions were pH 6.1 (mucosal solution) and pH 7.4 (serosal solution) with a bilateral osmolarity of 293 mOsm/L. During the challenge period, the mucosal side of the epithelia was exposed to either an acidotic challenge (pH 5.2, osmolarity 293 mOsm/L) or an osmotic challenge (pH 6.1, osmolarity 450 mOsm/L); a third group served as control (pH 6.1, osmolarity 293 mOsm/L). The mucosal buffer solution was replaced for the recovery period. In vivo, sheep on the SARA treatment had lower mean (5.77 vs. 6.67) and nadir (5.48 vs. 6.47) ruminal pH for the 3 h following the oral drench compared with sham sheep, indicating the successful induction of SARA with the oral glucose dose. Despite the marked reduction in pH in vivo, induction of SARA had no detectable effects on the baseline measurements of J_mannitol-SM, tissue conductance (G_t), and short-circuit current (I_sc) in vitro. However, reducing mucosal pH to 5.2 in vitro had negative effects on epithelial barrier function in the recovery period, including increased J_mannitol-SM, increased G_t, and decreased I_sc. The osmotic challenge increased J_mannitol-SM and G_t and decreased I_sc during the challenge period, which was reversible in the recovery period except for slight reduction in I_sc. Interactions between the in vitro treatment and measurement period were detected for J_mannitol-SM, G_t, and I_sc. These data indicate that a mild episode of SARA (nadir pH, 5.48; duration ruminal pH <5.8, 111 min relative to the 180-min measurement period) does not affect ruminal epithelial barrier function immediately after the episode but that a rapid and more severe acidification (pH 5.2) in vitro increases epithelial permeability following the insult.     

Model-based automation of the design of user interfaces to digitalcontrol systems

Digital control systems, like those controlling the functions of buildings or industrial processes, pose a number of special problems for good user interface design. The general problems of providing usability, common to all systems, include difficulty in accessing and applying principles of good design. In addition, digital control systems can have multiple users, with multiple roles, and each installation has different configurations of systems, controls, and user interface devices. Providing interactions for the users of building control systems is often achieved by manually implementing each required display. This is an expensive solution, which often produces less than optimal results. We address these problems through the automation of user interface design. Our solution, called DIGBE (dynamic interface generation for building environments), separates the domain knowledge, interaction design, and presentation heuristics into multiple collaborating models. Each model contains knowledge about a particular aspect of interface design, and uses this knowledge to dynamically create each user interface that is needed to support the users of a control system. DIGBE demonstrates that it is possible to automatically and dynamically create consistent and individualized user interfaces from model-based design knowledge     

Fenestration devices for energy conservation—I. Energy savings during the cooling season

Equations are presented for estimating heat transfer through seven types of fenestrations using the properties of the shading devices and the conditions of the interior and exterior environments. The results have been employed to determine energy savings during the cooling season for buildings located in the transition climatic region of San Diego County. Life-cycle costs for installing various types of shading devices are estimated on the assumption that the shading devices are removed during the heating season or else have no effect on heating-season requirements.     

Multimode detection of hydrogen gas using palladium-covered silicon micro-channels

Palladium was electrodeposited onto lithographically patterned Si(100) "micro-channels" with dimensions of 2 microm (width) x 100 microm (length). The properties of these Pd-covered Si micro-channels for detecting dihydrogen gas were then evaluated. Pd electrodeposition was carried out under conditions favoring an instantaneous nucleation and growth mechanism. This strategy produced size-similar Pd particles at a coverage of (4-6) x 10(9) cm(-2) within the confines of the Si micro-channel. When the mean particle radius, ro, was smaller than a critical value (ro < rc = 70-85 nm), each Pd particle was well separated on the surface from adjacent particles, on average, and no response to H2 gas attributable to the micro-channel was observed. As Pd particles were grown larger, to a mean radius of ro approximately equal to rc, adjacent particles on the surface touched and the electrical resistance of the micro-channel dropped by several orders of magnitude. These "type 2" H2 sensors exhibited a rapid (< 1 s), reversible decrease in their resistance in response to exposure to H2 above 0.5%, but a minimum resistance was observed at 1-2%, and a resistance increase was seen at higher H2 concentration. This complex behavior resulted from the existence of three mechanisms for charge transport across the micro-channel. If still larger quantities of Pd were deposited, the Pd particle ensemble coalesced into an electrically continuous film. These "type 3" sensors became more resistive in the presence of H2, not more conductive as seen for sensors of types 1 and 2, but the amplitude of this response was smaller than seen for type 2 sensors.     

Automated Phase Design and Timing Adjustment for Signal Phase Design

In this paper we describe the design processes of human traffic engineers and the development of an automated system that solves the problem of timing adjustment in signal phase sequence design. Signal phase sequencing refers to the sequence of signal changes and the timing of each change for a system of traffic lights at an isolated intersection. In designing signal sequences, one must decide how much time to allocate for each phase of the sequence so that traffic can flow with a minimum of delay. Other automated phase design systems can generate an initial phase design, but if the initial design is not precisely correct, the timing sequence must be adjusted by hand. This paper presents TIMELY, an automated signal phase design generator that generates an initial phase design and automatically adjusts the timing if necessary. TIMELY uses an interactive redesign strategy which largely mimics that used by human experts. The system invokes a set of redesign rules (which we have dubbed the Robin Hood procedure), gathered from human experts, which tweak the phase design. The new design is fed back into a simulator and tested again. The process stops when we find that the average delay is not improved. We take the design from the previous step as our final design. An expert has verified the soundness of all of TIMELY's results.     

Premorbid anomalies and risk of schizophrenia and depressive disorders in a birth cohort exposed to prenatal rubella.

In a birth cohort prenatally exposed to rubella, we assessed whether prospectively documented premorbid neuromotor dysfunction, mannerisms, deviant behaviors, and temperament during childhood and adolescence were impaired in cases who developed depressive disorder (DD) relative to rubella-exposed controls and cases who developed schizophrenia spectrum psychosis (SSP). Premorbid neuromotor dysfunction and mannerisms were not increased among DD cases compared to controls or SSP cases. With regard to temperament, approachability was greater in DD cases than in controls and SSP cases. There were numerical increases in the proportions of DD cases with premorbid deviant behaviors compared to controls, but the findings fell short of statistical significance; the proportion of subjects with deviant behaviors in DD cases was similar to that found for SSP. These results indicate that premorbid neuromotor dysfunction and mannerisms may be specific to SSP among major psychiatric disorders in this cohort, and suggest that premorbid deviant behaviors are increased in both DD and SSP. Greater premorbid approachability may be associated with an increased risk of adult DD. Implications of these findings for school psychology are furnished. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Scattering and Absorption by Elongated Aerosol Particles

Recently we developed a new technique, the iterative extended boundary condition method, which is suitable for calculating the scattering and absorption by elongated particles in a broad frequency range, including at resonance. This paper briefly describes this technique, illustrates its capabilities, and presents the results of its most recent extensions. This includes the implementation of a sectioning procedure and the use of a new segmentation method for calculating scattering by very long oriented chains of aerosols. Results of absorption cross sections in two different frequency ranges, visible and infrared, and for two different polarizations, parallel and end-fire polarizations, will be presented. The range of validity of some reported relationships between scattering from a single particle and from coagulated particles are discussed. It is shown that in the end-fire polarization case the sum of the absorption by separate n particles (P _sum) is more than the absorption by a chain of n coagulated particles (P _end-fire), while in the parallel polarization case, the ratio between P _parallel/P _end-fire may be as high as a factor of 4. This observation emphasizes the importance of taking the polarization into account in calculating light scattering by elongated chains of aerosols.     

Steps toward passively safe, proliferation-resistant nuclear power

After about a 30-year hiatus of construction in the US but not in all involved countries, the designs for an improved water-cooled nuclear reactor will hopefully be developed by a consortium of nuclear reactor builders and users under an agreement with the US Department of Energy (DOE) and review by the Nuclear Regulatory Commission (NRC). The construction of high-temperature, helium-cooled pebble-bed or prismatic reactors may herald the entry of new, safer, and less costly types of reactors to replace the water-cooled reactors of the past and current types. Nuclear breeder reactors hold the promise of limitless energy supplies without the use of fossil fuels or renewables at acceptable costs but this development program has been stalled periodically, especially in the US, when abundant low-cost uranium sources were added to the supply side.