Priming of Cardiopulmonary Bypass with Human Albumin Decreases Endothelial Dysfunction after Pulmonary Ischemia–Reperfusion in an Animal Model

The routine use of mechanical circulatory support during lung transplantation (LTx) is still controversial. The use of prophylactic human albumin (HA) or hypertonic sodium lactate (HSL) prime in mechanical circulatory support during LTx could prevent ischemia–reperfusion (IR) injuries and pulmonary endothelial dysfunction and thus prevent the development of pulmonary graft dysfunction. The objective was to investigate the impact of cardiopulmonary bypass (CPB) priming with HA and HSL compared to a CPB prime with Gelofusine (GF) on pulmonary endothelial dysfunction in a lung IR rat model. Rats were assigned to four groups: IR-CPB-GF group, IR-CPB-HA group, IR-CPB-HSL group and a sham group. The study of pulmonary vascular reactivity by wire myograph was the primary outcome. Glycocalyx degradation (syndecan-1 and heparan) was also assessed by ELISA and electron microscopy, systemic and pulmonary inflammation by ELISA (IL-1β, IL-10, and TNF-α) and immunohistochemistry. Clinical parameters were evaluated. We employed a CPB model with three different primings, permitting femoral–femoral assistance with left pulmonary hilum ischemia for IR. Pulmonary endothelium-dependent relaxation to acetylcholine was significantly decreased in the IR-CPB-GF group (11.9 ± 6.2%) compared to the IR-CPB-HA group (52.8 ± 5.2%, p < 0.0001), the IR-CPB-HSL group (57.7 ± 6.3%, p < 0.0001) and the sham group (80.8 ± 6.5%, p < 0.0001). We did not observe any difference between the groups concerning glycocalyx degradation, and systemic or tissular inflammation. The IR-CPB-HSL group needed more vascular filling and developed significantly more pulmonary edema than the IR-CPB-GF group and the IR-CPB-HA group. Using HA as a prime in CPB during Ltx could decrease pulmonary endothelial dysfunction’s IR-mediated effects. No effects of HA were found on inflammation.     

An experimental investigation of high permittivity dielectric resonators for millimeter-wave microstrip components

This paper proposes a new type of high permittivity whispering gallery mode cylindrical dielectric resonators with a geometry which is very suitable for use in microstrip type integrated circuits. These “oversized” resonators, together with high Q factors and ease of fabrication, are potentially interesting for millimeter wave integrated filters and oscillators. In this paper, we report an experimental investigation of such resonators carried out in Ka band (26.5–40 GHz). Measured results including resonant frequencies and loaded quality factors will be presented. Application to millimeter wave filters will also be demonstrated.     

Atmospheric reactions influence seasonal PAH and nitro-PAH concentrations in the Los Angeles basin

Ambient measurements of polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs were carried out during August 2002 and January 2003 in Los Angeles, CA, a source site and in Riverside, CA, a downwind receptor site approximately 90 km to the east of Los Angeles. Atmospheric concentrations of PAHs and nitro-PAHs are of interest because both of these compound classes include potent mutagens and carcinogens. To augment our current understanding of atmospheric formation of nitro-PAHs, four sampling periods were employed to study the diurnal variations of these compounds. The PAH concentrations were highest in Los Angeles during January, as a result of traffic input at this source site undertightwintertime atmospheric inversions. In contrast, nitro-PAH levels were highest in Riverside during August, as a result of enhanced summertime photochemistry. Hydroxyl radical-initiated reactions produced nitro-PAHs in both seasons, while in winter little evidence for nitrate radical chemistry was seen. For the August samples, nitrate radical-initiated formation of nitro-PAHs is suggested by nitro-PAH isomer profiles not only at the downwind location as anticipated, but also atthe source site. In southern California, the contribution of atmospheric formation through gas-phase radical-initiated PAH reactions to the ambient burden of nitro-PAHs is dominant, with the semi-volatile nitro-PAHs being the most abundant and 2-nitrofluoranthene being the major particle-associated nitro-PAH.     

High‐Temperature Creep Behavior of SiOC Glass‐Ceramics: Influence of Network Carbon Versus Segregated Carbon

Three silicon oxycarbide samples with different carbon contents are analyzed in the present study with respect to their high‐temperature creep behavior. The tests were performed in compression at 1100°C, 1200°C, and 1300°C; in this temperature range the mechanism of creep relies on viscoelastic flow within the samples and has been modeled with the Jeffreys viscoelastic model. After the release of the applied mechanical stress, a viscoelastic recovery behavior was observed in all samples. The creep behavior of the investigated samples indicates two rheological contributions in SiOC: (i) a high viscous answer, coming from the silica‐rich network, and (ii) an elastic response from the segregated carbon phase within the samples. Furthermore, two distinct effects of the carbon phase on the HT creep behavior of SiOC were identified and are discussed in the present paper: the effect of the carbon presence within the SiOC network (the “carbidic” carbon), which induces a significant increase in the viscosity and a strong decrease in the activation energy for creep, as compared to vitreous silica; and the influence of the segregated carbon phase (the “free” carbon), which has been shown to affect the viscosity and the activation energy of creep and dominates the creep behavior in phase‐separated silicon oxycarbides.     

Dielectric resonators suitable for use in planar integratedcircuits at short millimeter wavelengths

Experimental results are presented of planar whispering-gallery-mode dielectric resonators. The three-dimensional field pattern obtained by using finite-element techniques as well as measured resonant frequencies and quality factors carried out in the Ka (26.5-40 GHz) and 90-100-GHz bands is presented. The application to millimeter-wave components is discussed     

Effect of autoclaving sugar-beet fibre on its physico-chemical properties and its in-vitro degradation by human faecal bacteria

The effect of structure and properties of sugar-beet fibre on its degradability by human faecal bacteria was investigated by an in-vitro fermentation test. The composition and physico-chemical properties of sugar-beet fibre were changed by autoclaving. Autoclaving at 122°C and 136°C for I h increased the solubility mainly of pectins and arabinans and caused increased swelling. The form of the fibre influenced the water-binding capacity, the ionic form giving lowest values. Increasing the ionic strength of the medium reduced the water-binding capacity, especially for the raw fibres and fibres autoclaved at 122°C. The composition of the fibre did not entirely explain these differences and the three-dimensional arrangement of the different polymers in the cell wall was apparently involved. Galacturonic acid and arabinose were extensively depleted by human faecal bacteria and after 24h more than 80% of the initial carbohydrates had been degraded. However, the time course measurement of residual polysaccharides, production of short-chain fatty acids and values of pH showed differences in the rate of fermentation; the presence of solubilised material stimulated bacterial proliferation. The removal of pectic polysaccharides increased the degradability of cellulose and this fact suggested that accessibility is mainly responsible for the slow attack of cellulose in sugar-beet fibre.     

Circular polarization of the magnetic field in the WG modes ofresonance of a dielectric disc at microwave frequencies

The circular polarization of the magnetic field of the whispering-gallery (WG) modes of resonance of a dielectric disk resonator was tested in the evanescent-field region outside the dielectric material. Microwaves in the frequency range from 18 to 26.5 GHz (K-band) and the techniques of electron spin response (ESR) were used. The distribution of the electromagnetic fields was obtained with a finite element method, and it was found to be in agreement with the experimental results     

Effects of feedback in a computer-based assessment for learning

The effects of written feedback in a computer-based assessment for learning on students’ learning outcomes were investigated in an experiment at a Higher Education institute in the Netherlands. Students were randomly assigned to three groups, and were subjected to an assessment for learning with different kinds of feedback. These are immediate knowledge of correct response (KCR) + elaborated feedback (EF), delayed KCR + EF, and delayed knowledge of results (KR). A summative assessment was used as a post-test. No significant effect was found for the feedback condition on student achievement on the post-test. Results suggest that students paid more attention to immediate than to delayed feedback. Furthermore, the time spent reading feedback was positively influenced by students’ attitude and motivation. Students perceived immediate KCR + EF feedback to be more useful for learning than KR. Students also had a more positive attitude towards feedback in a CBA when they received KCR + EF rather than KR only.     

Parallel extraction and simplification of large isosurfaces using an extended tandem algorithm

In order to deal with the common trend in size increase of volumetric datasets, in the past few years research in isosurface extraction has focused on related aspects such as surface simplification and load-balanced parallel algorithms.We present a parallel, block-wise extension of the tandem algorithm [Attali D, Cohen-Steiner D, Edelsbrunner H. Extraction and simplification of iso-surfaces in tandem. In: SGP ’05: Proceedings of the third Eurographics symposium on Geometry processing. Aire-la-Ville, Switzerland: Eurographics Association; 2005. p. 139-148], which simplifies on the fly an isosurface being extracted. Our approach minimizes the overall memory consumption using an adequate block splitting and merging strategy along with the introduction of a component dumping mechanism that drastically reduces the amount of memory needed for particular datasets such as those encountered in geophysics. As soon as detected, surface components are migrated to the disk along with a meta-data index (oriented bounding box, volume, etc.) that permits further improved exploration scenarios (small component removal or particularly oriented component selection for instance).For ease of implementation, we carefully describe a master and worker algorithm architecture that clearly separates the four required basic tasks. We show several results of our parallel algorithm applied on a geophysical dataset of size 7000×1600×2000.