Mass determination of the fatty acids released from tannin-stimulated rabbit alveolar macrophages

Previous studies with macrophages that had been prelabeled with [¹⁴C]arachidonic acid (20∶4) have shown that condensed tannin is a potent agonist for the release of arachidonic acid. However, it has not been demonstrated that the percentage release of [¹⁴C]20∶4 accurately reflects the metabolic activity of the endogenous 20∶4 pool. In order to measure the 20∶4 mass release relative to the total cellular 20∶4 pool, the free fatty acids of freshly isolated alveolar macrophages were derivatized with a fluorescent reagent, and then separated and quantified by high-performance liquid chromatography. The amounts of esterified fatty acids were measured by gas chromatography of the methyl esters. Free fatty acid levels were compared to those of the total esterified plus unesterified fatty acids to determine the actual percentage released of each fatty acid. Tannin-stimulated release of 20∶4 mass reflected that previously reported for the release of [¹⁴C]20∶4 label but at a slower rate and at a much lower percentage indicating that [¹⁴C]20∶4 had been incorporated into part of a more reactive pool. The specificity of the fatty acid release induced by tannin and β-1,3-glucan, a known agonist for 20∶4 release, was also examined. Both agonists promoted an increase in the levels of free 20∶4 and of other fatty acids. A comparison of the absolute increases of each of the fatty acids indicated that tannin caused a preferential increase in the mass of free 20∶4, whereas β-1,3-glucan evoked a selective increase in the mass of 16∶0. Deceased.     

Some theorems of the eddy-current theory

Contents In the paper, theorems for the electric vector potentialT and magnetic scalar potentialU are discussed, which occur in the boundary-value problems for eddy currents induced in a conducting block by an external magnetic field. Uniqueness of the solution is examined. An integral representation of the scalar potentialU is derived for a nonmagnetic conductor. It is shown that for a thin metallic shell the integrodifferential equation results from general formulas related to the block.

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Einige Theoreme der Wirbelstromtheorie

Übersicht In der Arbeit werden drei Theoreme für das elektrische VektorpotentialT und das magnetische SkalarpotentialU beschrieben, die in den Randwertaufgaben für in einem metallischen Block durch das äußere magnetische Feld induzierte Wirbelströme auftreten. Es wird bewiesen, daß eine solche Randwertaufgabe eine eindeutige Lösung hat, wenn das Vektorpotential auf dem Rand gleich Null ist. Eine Integralrepräsentation des Skalarpotentials wird abgeleitet. Es wird gezeigt, daß die Integrodifferentialgleichung für eine dünne metallische Hülle aus allgemeinen, den Block betreffenden Formeln hervorgeht.

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List of principal symbols e coordinate unit vector - H magnetic intensity - J current density - T electric vector potential - U magnetic scalar potential - permeability - conductivity - V boundary of regionV     

Korrosion von ölgefeuerten Zentralheizungskesseln

Corrosion of oil-fired domestic boilers Depending on the surface temperature of the flue gas side the corrosion of oil fired domestic boilers proceeds either mainly by acid corrosion or by oxygen corrosion:

• – At surface temperatures of 60°C and higher the corrosion mechanism of acid corrosion prevails and the corrosion rates amount to 0.1–0.3 mm/year (values referred to continuous burner operation). The corrosion products consist of soluble iron(II)- and iron(III)sulfates. Higher corrosion rates can be attributed to an appreciable catalytic formation of sulfur trioxide on the corrosion products formed on the convective heating surfaces.
• – At surface temperatures of 40°C the mechanism of oxygen corrosion already dominates and the corrosion rates are about ten times higher (1.5–3 mm/year, referred to continous burner operation). The high portion of ioron oxide hydrates, especially goethit (α-FeOOH), makes the corrosion products difficult to remove.
• – Distinctly reduced service lives are also expected for the so called reduced temperature boilers (“Niedertemperaturkessel”) and low temperature boiers (“Tieftemperaturkessel”): According to the manufacturers these boilers may be operated at boiler water temperatures well below 60°C, as they are equipped with constructive measures to enhance the surface temperature on the flue gas side. However, these measures are only fully effective under stationary conditions.

Some of the results were obtained from weight loss measurements on test specimen made from St 35.8 and gray cast iron, that were exposed to the flue gases of an oil fired experimental boiler. Other important results come from field measurements of the sulfuric acid content of about 30 boilers that are in practical use.     

A prototype scanning stylus profilometer for rapid measurement of small surface areas

A novel stylus based profiling instrument has been developed for rapid measurement of small surface areas. Outlined in the following paper are some of the key features of the prototype system including the wideband stylus pick-up and the dedicated scanning traverse mechanism. In addition, some preliminary results obtained by scanning the instrument over several different surfaces are presented.     

Interval or moments: which carry more information?

In many practical situations, we do not have enough observations to uniquely determine the corresponding probability distribution, we only have enough observations to estimate two parameters of this distribution. In such cases, the traditional statistical approach is to estimate the mean and the standard deviation. Alternatively, we can estimate the two bounds that form the range of the corresponding variable and thus, generate an interval. Which of these two approaches should we select? A natural idea is to select the most informative approach, i.e., an approach in which we need the smallest amount of additional information (in Shannon’s sense) to obtain the full information about the situation. In this paper, we follow this idea and come up with the following conclusion: in practical situations in which a 95 % confidence level is sufficient, interval bounds are more informative; however, in situations in which we need higher confidence, the moments approach is more informative.     

Radiometric normalization and image mosaic generation of ASTER thermal infrared data: An application to extensive sand sheets and dune fields

Data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) have a significant advantage over previous datasets because of the combination of high spatial resolution (15-90 m) and enhanced multispectral capabilities, particularly in the thermal infrared (TIR) atmospheric window (8-12 μm) of the Earth where common silicate minerals are more easily identified. However, the 60 km swath width of ASTER can limit the effectiveness of accurately tracing large-scale features, such as eolian sediment transport pathways, over long distances. The primary goal of this paper is to describe a method for generating a seamless and radiometrically accurate ASTER TIR mosaic of atmospherically corrected radiance and from that, extract surface emissivity for arid lands, specifically, sand seas. The Gran Desierto in northern Sonora, Mexico was used as a test location for the radiometric normalization technique because of past remote sensing studies of the region, its compositional diversity, and its size. A linear approach was taken to transform adjacent image swaths into a direct linear relationship between image acquisition dates. Pseudo-invariant features (PIFs) were selected using a threshold of correlation between radiance values, and change-pixels were excluded from the linear regression used to determine correction factors. The degree of spectral correlation between overlapping pixels is directly related to the amount of surface change over time; therefore, the gain and offsets between scenes were based only on regions of high spectral correlation. The result was a series of radiometrically normalized radiance-at-surface images that were combined with a minimum of image edge seams present. These edges were subsequently blended to create the final mosaic. The advantages of this approach for TIR radiance (as opposed to emissivity) data include the ability to: (1) analyze data acquired on different dates (with potentially very different surface temperatures) as one seamless compositional dataset; (2) perform decorrelation stretches (DCS) on the entire dataset in order to identify and discriminate compositional units; and (3) separate brightness temperature from surface emissivity for quantitative compositional analysis of the surface, reducing seam-line error in the emissivity mosaic. The approach presented here is valid for any ASTER-related study of large geographic regions where numerous images spanning different temporal and atmospheric conditions are encountered.     

Using physical memorabilia as opportunities to move into collocated digital photo-sharing

The uptake of digital photos vs. print photos has altered the practice of photo-sharing. Print photos are easy to share within the home, but much harder to share outside of it. The opposite is true of digital photos. People easily share digital photos outside the home, e.g., to family and friends by e-mail gift-giving, and to social networks and the broader public by web publishing. Yet within the home, collocated digital photo-sharing is harder, primarily because digital photos are typically stored on personal accounts in desktop computers located in home offices. This leads to several consequences. (1) The invisibility of digital photos implies few opportunities for serendipitous photo-sharing. (2) Access control and navigation issues inhibit family members from retrieving photo collections. (3) Photo viewing is compromised as digital photos are displayed on small screens in an uncomfortable viewing setting.To mitigate some of these difficulties, we explore how physical memorabilia collected by family members can create opportunities that encourage social and collocated digital photo-sharing. First, we studied (via contextual interviews with 20 households) how families currently practice photo-sharing and how they keep memorabilia. We identified classes of memorabilia that can serve as memory triggers to family events, trips, and times when people took photos. Second, we designed Souvenirs, a photo-viewing system that exploits memorabilia as a social instrument. Using Souvenirs, a family member can meaningfully associate physical memorabilia with particular photo-sets. Later, any family member can begin their story-telling with others through the physical memento, and then enrich the story by displaying its associated photos simply by moving the memento close to the home's large-format television screen. Third, we re-examined our design premises by evoking household reactions to an early version of Souvenirs. Based on these interviews, we redesigned Souvenirs to better reflect the preferences and real practices of photo and memorabilia use in the home.     

A Managed IPv6 Transitioning Architecture for Large Network Deployments

With IPv6 transitioning still in a relative state of flux, the need has emerged for methods to control this crucial aspect of IPv6 deployments. This article makes the case for transitioning architectures as a realistic solution to this issue, specifically within large-scale networks. The Site Transitioning Architecture (STA) supports the deployment, operation, and management of IPv6 transitioning mechanisms. The authors provide an overview of the STA's design and operation, noting that its flexible, simple, and secure architecture is suitable for the duration of the IPv6 deployment process, regardless of the underlying network environment.