Averaging of nonsmooth systems using dither

It was shown by Zames and Shneydor and later by Mossaheb that a high-frequency dither signal of a quite arbitrary shape can be used to narrow the effective nonlinear sector of Lipschitz continuous feedback systems. In this paper, it is shown that also discontinuous nonlinearities of feedback systems can be narrowed using dither, as long as the amplitude distribution function of the dither is absolutely continuous and has bounded derivative. The averaged system is proven to approximate the dithered system with an error of the order of dither period.     

Personal Exposure in Displacement Ventilated Rooms

Personal exposure in a displacement ventilated room is examined. The stratified flow and the considerable concentration gradients necessitate an improvement of the widely used fully mixing compartmental approach. The exposure of a seated and a standing person in proportion to the stratification height is examined by means of full-scale measurements. A breathing thermal manikin is used to simulate a person. It is found that the flow in the boundary layer around a person is able to a great extent to entrain and transport air from below the breathing zone. In the case of non-passive, heated contaminant sources, this entrainment improves the indoor air quality. Measurements of exposure due to a passive contaminant source show a significant dependence on the flow field as well as on the contaminant source location. Poor system performance is found in the case of a passive contaminant released in the lower part of the room close to the occupant. A personal exposure model for displacement ventilated rooms is proposed. The model takes the influence of gradients and the human thermal boundary layer into account. Two new quantities describing the interaction between a person and the ventilation are defined.     

A fast analog mean-timer

A circuit is described that determines the average of the transit time of light from an event in a scintillation counter to the two ends of that counter. The design offers superior time resolution and a novel gating scheme that significantly reduces circuit dead-time.     

Design and structural applications of stress-crack width relations in fibre reinforced concrete

The stress-crack width relationship has been shown to be the key to an understanding of fracture propagation in and mechanical behaviour in tension of fibre reinforced concrete materials and structures. A model is derived for the stress-crack width relationship for randomly oriented short fibre composites which takes hybrid fibre systems and possible fibre rupture into account. It is shown how this stress-crack width relationship can be included in a structural model for the prediction of crack widths in reinforced concrete structures. With this combination of models a rational design tool for the design of composite materials and structures has been established. It is shown how different fibre systems can be tested for structural applicability and how combined material and structural optimization can take place.     

Storage life of frozen salmonoids Effect of light and packaging conditions on carotenoid oxidation and lipid oxidation

Summary The combined effect of oxygen transmission of packaging material and of exposure to light with different spectral distribution on the oxidative degradation of carotenoids and lipids in frozen salmonoids has been characterized in a storage experiment with steaks of rainbow trout. The degradation of the carotenoid astaxanthin, as followed by HPLC analysis and tristimulus colorimetric measurement, was sensitive to the radiant flux density of UV light and less sensitive to the oxygen transmission rate of the packaging material, in agreement with previous findings for photooxidation of carotenoids in food model systems. This is in contrast to the lipid oxidation, which was found to be dependent on the accessability of oxygen rather than on exposure to UV light. Formation of peroxides in the product culminated after 3 months of storage (up to 8.4 mEq kg^–1 oil), and preceded the formation of thiobarbituric-acid-reactive substances. The product in packaging material with a high oxygen transmission rate (60 cm³ m^–2 bar^–1 per 24 h) reached a level of approximately 5 mol malonaldhyde/kg^–1 product, when stored exposed to standard fluorescent light or fluorescent light with a high UV component. Rancid taste was not detected by sensory evaluation for any of the products after 6 months of storage, whereas a bitter taste was noted for the product exposed to UV light.

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Die Haltbarkeit von Lachsforellen Einfluß von Licht und Verpackung auf die Carotenoid- und Fettoxydation

Zusammenfassung Der kombinierte Effekt von Sauerstoffdurchgang durch Verpackungsmaterial und der Lichteinwirkung verschiedener spektraler Verteilung auf den oxidativen Abbau der Carotinoide und Fette in gefrorenen Lachsforellen wurde in einem Lagerungsversuch untersucht. Der Abbau des Carotenoids Astaxanthin wurde mit HPLC undTristimulus-Calorimetrie beobachtet, und war empfindlich gegenüber UV-Licht und weniger empfindlich gegenüber der Sauerstoffdurchlässigkeit der Verpackung, was mit früheren Ergebnissen für Photooxidation der Carotinoide in Modellsystemen übereinstimmt. Dies widerspricht der Fettoxidation, die mehr von Sauerstoffzugang abhängig ist als von der Entwicklung des UV-Lichtes. Die Bildung von Peroxiden des Produktes kuliminierte nach 3monatiger Lagerung (bis 8,4 meq/kg Öl) und ging der Bildung von Thiobarbitursäure-aktiven Substanzen voraus. Das Produkt im Material mit hohem Sauerstoffdurchgang (60 cm³ m^–2 bar^–1 pro 24 h), das bei normalen fluorescierendem Licht oder bei fluorescierendem Licht mit hohem UV-Anteil aufbewahrt wurde, erreichte einen TBS-Wert von ungefähr 5 mol Malonaldehyd/kg Fleisch. Ein ranziger Geschmack wurde durch sensorische Bewertung nach 6monatiger Lagerung nicht erkannt, wohl aber ein bitterer Geschmack bei dem UV-Licht ausgesetzten Proben.

     

Dysregulated CD38 Expression on Peripheral Blood Immune Cell Subsets in SLE

Given its uniformly high expression on plasma cells, CD38 has been considered as a therapeutic target in patients with systemic lupus erythematosus (SLE). Herein, we investigate the distribution of CD38 expression by peripheral blood leukocyte lineages to evaluate the potential therapeutic effect of CD38-targeting antibodies on these immune cell subsets and to delineate the use of CD38 as a biomarker in SLE. We analyzed the expression of CD38 on peripheral blood leukocyte subsets by flow and mass cytometry in two different cohorts, comprising a total of 56 SLE patients. The CD38 expression levels were subsequently correlated across immune cell lineages and subsets, and with clinical and serologic disease parameters of SLE. Compared to healthy controls (HC), CD38 expression levels in SLE were significantly increased on circulating plasmacytoid dendritic cells, CD14⁺⁺CD16⁺ monocytes, CD56⁺ CD16^dim natural killer cells, marginal zone-like IgD⁺CD27⁺ B cells, and on CD4⁺ and CD8⁺ memory T cells. Correlation analyses revealed coordinated CD38 expression between individual innate and memory T cell subsets in SLE but not HC. However, CD38 expression levels were heterogeneous across patients, and no correlation was found between CD38 expression on immune cell subsets and the disease activity index SLEDAI-2K or established serologic and immunological markers of disease activity. In conclusion, we identified widespread changes in CD38 expression on SLE immune cells that highly correlated over different leukocyte subsets within individual patients, but was heterogenous within the population of SLE patients, regardless of disease severity or clinical manifestations. As anti-CD38 treatment is being investigated in SLE, our results may have important implications for the personalized targeting of pathogenic leukocytes by anti-CD38 monoclonal antibodies.     

Comparison of a contactor catalytic membrane reactor with a conventional reactor: example of wet air oxidation

A wet air oxidation reaction was carried out in a gas/liquid catalytic membrane reactor of the contactor type. The oxidation of formic acid was used as a model reaction. The mesoporous top-layer of a ceramic tubular membrane was used as catalyst (Pt) support, and was placed at the interface of the gas (air) and liquid (HCOOH solution) phases.

A similar reaction was carried out in a conventional batch reactor, using a steering rate high enough to avoid gas-diffusion limitations, and exactly identical conditions than for the CMR (amount of catalyst, pressure, etc.). At room temperature, the CMR showed an initial activity three to six times higher than the conventional reactor. This activity increase was attributed to an easier oxygen access to the catalytic sites. Nevertheless, the catalytic membrane gradually deactivated after a few hours of operation. Different deactivation mechanisms are presented.