Emerging Role of Phospholipase-Derived Cleavage Products in Regulating Eosinophil Activity: Focus on Lysophospholipids,Polyunsaturated Fatty Acids and Eicosanoids

Eosinophils are important effector cells involved in allergic inflammation. When stimulated, eosinophils release a variety of mediators initiating, propagating, and maintaining local inflammation. Both, the activity and concentration of secreted and cytosolic phospholipases (PLAs) are increased in allergic inflammation, promoting the cleavage of phospholipids and thus the production of reactive lipid mediators. Eosinophils express high levels of secreted phospholipase A2 compared to other leukocytes, indicating their direct involvement in the production of lipid mediators during allergic inflammation. On the other side, eosinophils have also been recognized as crucial mediators with regulatory and homeostatic roles in local immunity and repair. Thus, targeting the complex network of lipid mediators offer a unique opportunity to target the over-activation and ‘pro-inflammatory’ phenotype of eosinophils without compromising the survival and functions of tissue-resident and homeostatic eosinophils. Here we provide a comprehensive overview of the critical role of phospholipase-derived lipid mediators in modulating eosinophil activity in health and disease. We focus on lysophospholipids, polyunsaturated fatty acids, and eicosanoids with exciting new perspectives for future drug development.     

Methanol Adsorption on V2O3(0001)

Well ordered V₂O₃(0001) layers may be grown on Au(111) surfaces. These films are terminated by a layer of vanadyl groups which may be removed by irradiation with electrons, leading to a surface terminated by vanadium atoms. We present a study of methanol adsorption on vanadyl terminated and vanadium terminated surfaces as well as on weakly reduced surfaces with a limited density of vanadyl oxygen vacancies produced by electron irradiation. Different experimental methods and density functional theory are employed. For vanadyl terminated V₂O₃(0001) only molecular methanol adsorption was found to occur whereas methanol reacts to form formaldehyde, methane, and water on vanadium terminated and on weakly reduced V₂O₃(0001). In both cases a methoxy intermediate was detected on the surface. For weakly reduced surfaces it could be shown that the density of methoxy groups formed after methanol adsorption at low temperature is twice as high as the density of electron induced vanadyl oxygen vacancies on the surface which we attribute to the formation of additional vacancies via the reaction of hydroxy groups to form water which desorbs below room temperature. Density functional theory confirms this picture and identifies a methanol mediated hydrogen transfer path as being responsible for the formation of surface hydroxy groups and water. At higher temperature the methoxy groups react to form methane, formaldehyde, and some more water. The methane formation reaction consumes hydrogen atoms split off from methoxy groups in the course of the formaldehyde production process as well as hydrogen atoms still being on the surface after being produced at low temperature in the course of the methanol ?? methoxy + H reaction.     

Computational simulations and optimization of flow and temperature distributions in a large-scale power plant building

For reduced carbon dioxide and pollutant emission, it is often as effective, if not more, to minimize energy use on the consumption side, as to maximize the efficiency on the power supply side. In this study, we seek to fully characterize and optimize the heating, ventilation, and air conditioning (HVAC) electrical energy use in a large-scale structure: a power-plant building that houses boilers, turbines and other operating equipment. We use a fully three-dimensional computational fluid dynamics (CFD) model of this building, measuring 80 m in width, 120 m in length and 60 m in height, replicating the complex internal and external geometries, in order to simulate the flow and temperature distributions under a wide range of ambient and HVAC operating conditions. The flow patterns and temperature distributions in this building structure are computationally simulated in detail, wherein the computed temperatures are validated through spot measurements. The detailed understanding of the flow patterns and temperature distributions then allows for optimization of the HVAC configuration. Identification of the problematic flow patterns and temperature mis-distributions, leads to some corrective measures, for optimization of the temperature distributions. The basic principles of fluid mechanics and heat transfer, applied in conjunction with CFD simulation results, can result in substantial improvements under both hot- and cold-weather conditions, in most cases with relatively simple, implementable modifications.     

Role of majority and minority carrier barriers silicon/organic hybrid heterojunction solar cells

A hybrid approach to solar cells is demonstrated in which a silicon p-n junction, used in conventional silicon-based photovoltaics, is replaced by a room-temperature fabricated silicon/organic heterojunction. The unique advantage of silicon/organic heterojunction is that it exploits the cost advantage of organic semiconductors and the performance advantages of silicon to enable potentially low-cost, efficient solar cells.     

Brominated flame retardants in seawater and atmosphere of the Atlantic and the Southern Ocean

Seawater and air samples were collected aboard the FS Polarstern during the cruises ANT-XXV/1 + 2 in the Atlantic and Southern Ocean in 2008. The particulate and dissolved phase in water and particulate and gaseous phase in air were analyzed separately for nine polybrominated diphenyl ethers (PBDEs) and six non-PBDE brominated flame retardants (BFRs). Air concentrations of 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE) and hexabromobenzene (HBB) in the gaseous and particulate phase (median = 0.56 pg m(-3) for DPTE and 0.92 pg m(-3) for HBB) were comparable to ∑(9)PBDEs (1.0 pg m(-3)). Pentabromotoluene (PBT) was detectable in ～30% of the gaseous phase samples, whereas concentration of 2,4,6-tribromophenyl allylether (ATE), hexachlorocyclopentenyl-dibromocyclooctane (HCDBCO) and 2-ethyl-1-hexyl 2,3,4,5-tetrabromobenzoate (EHTBB) were below their method detection limits. DPTE, and PBDEs were also found in seawater at low pg per liter levels. Elevated seawater concentrations of PBDEs and DPTE were measured in the English Channel and close to South African coast. Concentrations of DPTE, BDE-47, and BDE-99 in the atmosphere generally decreased from Europe toward the Southern Ocean, whereas no latitudinal trend was observed in seawater. Air-water exchange gradients suggested net deposition dominates for all selected substances. The medians of net deposition fluxes for the air-water gas exchange were 83, 21, 69, 20, and 781 pg m(-2) day(-1) for BDE-47, BDE-100, BDE-99, DPTE, and HBB, whereas medians of dry deposition fluxes were 2.0, 0.3, 1.2, 1.0, and 0.5 pg m(-2) day(-1) for BDE-47, BDE-100, BDE-99, DPTE, and HBB. Overall, these results highlight the important role of the long-range atmospheric transport of PBDE and non-PBDE BFRs to remote regions.     

Base resistance and effective bandgap reduction in n-p-nSi/Si1-xGex/Si HBTs with heavy base doping

This paper presents a comprehensive study of the effects of heavy doping and germanium in the base on the dc performance of Si/Si_1-x Ge_x/Si npn Heterojunction Bipolar Transistors (HBTs). The lateral drift mobility of holes in heavily doped epitaxial SiGe bases affects the base sheet resistance while the effective bandgap is crucial for the vertical minority carrier transport. The devices used in this study were Si_1-xGe_x npn HBTs with flat Ge and B profiles in the base grown by Rapid Thermal Chemical Vapor Deposition (RTCVD). Hall and drift lateral hole mobilities were measured in a wide range of dopings and Ge concentrations. The drift mobility was indirectly measured based on measured sheet resistivity and SIMS measurements, and no clear Ge dependence was found. The Hall scattering factor is less than unity and decreases with increasing Ge concentration. The effective bandgap narrowing, including doping and Ge effects, was extracted from the room temperature collector current measurements over a wide range of Ge and heavy doping for the first time. We have observed bandgap narrowing due to heavy base doping which is, to first order, independent of Ge concentration, but less than that observed in silicon, due to the effect of a lower density of states. A model for the collector current enhancement with respect to Si devices versus base sheet resistance is presented     

Modulation of serotonin binding sites in the brain of the Djungarian hamster, Phodopus sungorus, during adaptation to a short photoperiod

During the physiological adaptation of the Djungarian hamster, Phodopus sungorus, to a short photoperiod in autumn the modulation of specific serotonin (5-HT) binding sites of synaptic membranes was investigated in two brain regions, i.e. cerebral cortex and basal brain (CNS without cerebral cortex, cerebellum, pineal gland, and spinal cord). The radioligands [3H]5-HT and [3H]ketanserin were used to characterize total 5-HT1 and 5-HT2 binding sites, respectively. An increase of 5-HT1 and 5-HT2 binding sites was observed in both brain regions within 14 days after reduction of the photoperiod from a 14:10 h light/dark (l/d) cycle to an 8:16 h l/d cycle. The increase was still present after 56 days of the short photoperiod. Binding kinetics assayed after 4 days of the short photoperiod show that maximal specific binding of [3H]5-HT and [3H]ketanserin was increased, while dissociation constants (KD) were not changed. The membrane anisotropy of synaptic membranes, measured by fluorescence polarization, was reduced transiently during the early part of the adaptation. Neither the phospholipids nor the mole ratio of cholesterol to phospholipids were significantly affected by adaptation to short photoperiod. The results suggest an important role of the central nervous 5-HT system in the physiological adaptation of the Djungarian hamster to a short photoperiod.     

Integration of organic LEDs and amorphous Si TFTs onto flexible andlightweight metal foil substrates

We report the integration of organic light emitting devices (OLEDs) and amorphous Si (a-Si) thin-film transistors (TFTs) on both glass, and unbreakable and lightweight thin stainless steel foil substrates. The doped-polymer OLEDs were built following fabrication of driver TFTs in a stacked structure. Due to the opacity of the steel substrate, top-emitting OLED structures were developed. It is shown that the a-Si TFTs provide adequate current levels to drive the OLEDs at video brightness (~100 cd/m²). This work demonstrates that lightweight and rugged TFT backplanes with integrated OLEDs are essential elements for robust and highly portable active-matrix emissive flat-panel displays     

Scanning force microscopic investigations of the femtosecond laser pulse irradiation of indium phosphide in air

Laser ablation of single-crystalline indium phosphide (InP) was performed in air by means of linearly polarized Ti : sapphire femtosecond pulses (800 nm, 130 fs, 10 Hz). As a result of the irradiation with a variable number of laser pulses per spot (N /spl les/ 5), several morphological changes (crater formation, rim formation, ripple structures, and cones) were observed. These effects were explored using force modulation microscopy (FMM), a technique based on scanning force microscopy, allowing the simultaneous imaging of both topography and local stiffness at a high lateral resolution. The first laser pulse induces the formation of a protruding rim (height < 20 nm, width /spl ap/ 300 nm) bordering the ablated crater. A Fourier analysis of the multipulse generated topographies reveals the formation of wavelength-sized periodic ripples (modulation depth < 100 nm) with an orientation perpendicular to that of the electric field vector of the laser radiation. Besides these morphological alterations, material modifications were also observed in the irradiated regions by means of the FMM technique. Within the ablated craters, local stiffness variations were found revealing an inhomogeneous material composition/structure as a consequence of the femtosecond pulse laser treatment.