New technologies in molecular allergodiagnostics

The article presents the characteristics of the ALEX2 (MacroArrayDX, Wien, Austria). It is designed for simultaneous detection of IgE total and specific IgE-aB to 120 extracts and 180 molecules by solid-phase enzyme immunoassay. Extracts and allergen molecules combined with nano-particles are sorbed on a solid-phase substrate, forming a macroscopic multiplex matrix - the immune allergy chip. The Institute of Clinical and Laboratory Standards (CLSI) conducted research on the verification and validation of the ALEX2 in relation to the ImmunoCAP macroarray test system (ThermoFisher Scientific, Uppsala, Sweden), which is often used in allergodiagnostics. The results obtained on the two test systems were comparable. One of the most important features of the ALEX2 test system is that unique allergen molecules and allergenic extracts are included in its composition, and a method has been found to inhibit cross-reactive hydrocarbon determinants (CCDs), which cause frequent non-specific binding of IgE-aT. The use of this test system makes it possible to carry out component allergy diagnostics with the determine of the dominant sensitizing factor in cases of mono- and polyvalent sensitization. The test results affect the determination of indications and the effectiveness of ASIT, allow assessing the risk of anaphylaxis and predicting further treatment tactics for the patient.

Saturation Point and Phase Envelope Calculation for Reactive Systems Based on the RAND Formulation

Analysis of multicomponent reactive systems requires reliable and accurate equilibrium calculation. There are many stoichiometric or non-stoichiometric methods to solve the flash-type calculations of a mixture in chemical and phase equilibrium. In contrast, there is a lack of robust and efficient methods for another important type of equilibrium calculation, the saturation point calculation or the calculation under the phase fraction specification (β-specification), for a reactive mixture. In this work, we developed RAND-based algorithms for calculating the saturation points and phase envelope of a reactive mixture. The RAND formulation is a non-stoichiometric approach recently extended to non-ideal mixtures for different flash specifications. We showed here how to modify the RAND-based flash formulation to solve the β-specification problems. We distinguished between two types of phase fractions, the one based on components and the one based on elements. They led to different constraint equations in the formulation. Furthermore, we introduced element-based partition coefficients, similar to the equilibrium ratios or K-factors used for non-reactive mixtures. Use of these new variables is essential to cross the critical point of a reactive mixture in the phase envelope construction. Since the formulation developed for reactive mixtures is general, it can also be reduced and used for the simpler non-reactive mixtures. We showed how the reduction could be made and how the reduced algorithm served as an alternative approach to the prevailing phase envelope algorithm of Michelsen. We illustrated the robustness and efficiency of the proposed algorithm using four examples: Pxy diagrams for CO2-NaCl brine, a solid-liquid T xy diagram for MgCl2-water, a PT phase envelope for a reactive mixture with the alkene hydration reaction, and a PT phase envelope for a non-reactive hydrocarbon mixture.

Simulation of Turbulent Mixing Effects on Essential NOx–O3–Hydrocarbon Photochemistry in Convective Boundary Layer

The turbulence kinetics model (TKM) describes an overall reaction rate for microscopic mass transfer phenomenon expressed as separation intensity, Is, in a turbulent reacting flow. This study examines the effects of turbulent mixing in the convective boundary layer (CBL) on essential NOx–O3–Hydrocarbon photochemistry containing sources of NO and a surrogate reactive hydrocarbon. The modeling approach applies for all species except OH with an assumption of a photostationary steady state. The TKM results reveal principal findings as follows: (1) effects of turbulence on reaction rates lead to significant segregations throughout most of the CBL in reaction pairs NO + O3, RH + OH and NO + HO2; (2) segregations permit significantly higher concentrations of NO and RH to build up and endure in the CBL than would occur for a non-turbulent atmosphere; (3) turbulent segregation influences limit and shift the ranges of NO and O3 concentrations compared to the non-turbulent case; (4) while there are differences between the TKM results and those for a published Large Eddy simulation (LES) of the same chemical system, there are also strong similarities. Therefore, a future study remains to compare model results to observations if and when appropriately time-resolved measurements of reacting species are obtained.

Effect of MoO3 as conditioning catalyst on synthesis of carbon nanotubes

The effect of nonsupported MoO3 as a conditioning catalyst on the preparation of carbon nanotubes (CNTs) using a common main catalyst Fe/MgO was investigated. Without using MoO3, only single-walled CNTs were produced at low yield. In contrast, the use of MoO3 provided single-walled and double-walled CNTs at high yield. The MoO3 conditioning catalyst enhances not only the yield but also the diameter and layer number of CNTs. The higher yield formation of more layered CNTs with larger diameter would be attributed to the preproduction of reactive hydrocarbon species by the conditioning catalyst and their growth to larger molecular-weight reactive species.

SCIAMACHY formaldehyde observations: constraint for isoprene emission estimates over Europe?

Formaldehyde (HCHO) is an important intermediate compound in the degradation of volatile organic compounds (VOCs) in the troposphere. Sources of HCHO are largely dominated by its secondary production from VOC oxidation, methane and isoprene being the main precursors in unpolluted areas. As a result of the moderate lifetime of HCHO, its spatial distribution is determined by reactive hydrocarbon emissions. We focus here on Europe and investigate the influence of the different emissions on HCHO tropospheric columns with the CHIMERE chemical transport model in order to interpret the comparisons between SCIAMACHY and simulated HCHO columns. Europe was never specifically studied before for these purposes using satellite observations. The bias between measurements and model is less than 20% on average. The differences are discussed according to the errors on the model and the observations and remaining discrepancies are attributed to a misrepresentation of biogenic emissions. This study requires the characterisation of: (1) the model errors and performances concerning formaldehyde. The errors on the HCHO columns, mainly related to chemistry and mixed emission types, are evaluated to 2×1015 molecule/cm2 and the model performances evaluated using surface measurements are satisfactory (~13%); (2) the observation errors that define the needs in spatial and temporal averaging for meaningful comparisons. Using SCIAMACHY observations as constraint for biogenic isoprene emissions in an inverse modelling scheme reduces their uncertainties by about a factor of two in region of intense emissions. The retrieved correction factors for the isoprene emissions range from a factor of 0.15 (North Africa) to a factor of 2 (Poland, the United Kingdom) depending on the regions.

SCIAMACHY formaldehyde observations: constraint for isoprene emissions over Europe?

Formaldehyde (HCHO) is an important intermediate compound in the degradation of volatile organic compounds (VOCs) in the troposphere. Sources of HCHO are largely dominated by its secondary production from VOC oxidation, methane and isoprene being the main precursors in unpolluted areas. As a result of the moderate lifetime of HCHO, its spatial distribution is determined by reactive hydrocarbon emissions. We focus here on Europe, never studied before, and investigate the influence of the different emissions on HCHO tropospheric columns with the CHIMERE chemical transport model in order to interpret the comparisons between SCIAMACHY and simulated HCHO columns. Observed columns present a bias less than 20% on average. The differences are discussed according to the errors on the model and the observations and the remaining discrepancies are attributed to a misrepresentation of biogenic emissions. This study requires the characterisation of: (1) the model errors and performances concerning formaldehyde. The errors on the HCHO columns, mainly related to chemistry and mixed emission types, are evaluated to 2×1015 molecule/cm2 and the model performances evaluated using surface measurements are satisfactory (~13%); (2) the observation errors that define the needs in spatial and temporal averaging for meaningful comparisons. Perspectives of using SCIAMACHY observations as constraint for biogenic isoprene emissions with an adapted averaging are approached: this new constraint should help to reduce their uncertainties more than 50% in region of intense emissions.