This paper presents the results of mass spectrometric investigations of the OH-initiated oxidative aging of α-pinene SOA under simulated tropospheric conditions at the large aerosol chamber facility ...AIDA, Karlsruhe Institute of Technology. In particular, the OH-initiated oxidation of pure pinic and pinonic acid, two well-known oxidation products of α-pinene, was investigated. Two complementary analytical techniques were used, on-line atmospheric pressure chemical ionization/mass spectrometry (APCI/MS) and filter sampling followed by liquid chromatography/mass spectrometry (LC/ESI-MS). The results show that 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), a very low volatile α-pinene SOA product and a tracer compound for terpene SOA, is formed from the oxidation of pinonic acid and that this oxidation takes place in the gas phase. This finding is confirmed by temperature-dependent aging experiments on whole SOA formed from α-pinene, in which the yield of MBTCA scales with the pinonic acid fraction in the gas phase. Based on the results, several feasible gas-phase radical mechanisms are discussed to explain the formation of MBTCA from OH-initiated pinonic acid oxidation.
Particle coating experiments were performed in a lab-scale fluidized bed with varying process parameters, such as spraying rate and air inlet temperature, leading to different drying conditions. ...Porous (γ-Al2O3) and non-porous (glass) initial particles were sprayed with a sodium benzoate solution. For each experiment, the particle size distribution as well as the layer porosity was measured. The results show a dependency of the layer porosity on the drying conditions, represented by the drying potential of the fluidization gas. The obtained relationship is expressed as a linear correlation, which can be used in process models. Apart from the experimental results, a model based on population balances and heat and mass balances is presented. Simulations performed using the obtained empirical correlation are in good agreement with experimental data.
The obtained empirical correlations for the layer porosity depending on the drying conditions, represented by the drying potential, are shown. In the experiments, sodium benzoate was used as a coating material and porous γ-Al2O3 particles (left) as well as non-porous glass beads (right) were used as cores. Display omitted
•We measured layer porosities, produced at different drying conditions, with an X-ray microtomograph.•The measured porosities were correlated with the drying conditions.•A process model considering growth, developing porosity and drying was developed.•Simulations performed using the obtained empirical correlation are in good agreement with experimental data.
Angioedema is an underestimated clinical problem. Many cases are nonallergic reactions, e.g. bradykinin-induced angioedema caused by genetic defects and angiotensin-converting enzyme (ACE) ...inhibitors. This difference is crucial for successful therapy, in particular when complete emergency care is not available. Five important forms of nonallergic angioedema can be distinguished: hereditary (HAE), acquired (AAE), renin-angiotensin-aldosterone system (RAAS)-blocker-induced (RAE), pseudoallergic angioedema (PAE) and idiopathic angioedema (IAE). Some angioedema are present in the larynx and may cause death. A vast majority of nonallergic angioedema are RAE, particularly those caused by ACE inhibitors. It appears important to emphasize that in patients with complete intolerance to RAAS-blockers, cessation of RAAS-blockers is likely to be associated with increased cardiovascular risk. Currently, there is no published algorithm for diagnosis and treatment. Angioedema is usually treated by a conservative clinical approach using artificial ventilation, glucocorticoids and antihistamines. Today, a plasma pool C1-esterase inhibitor (C1-INH) concentrate is the therapy of choice in HAE. The current pharmacotherapy of nonallergic angioedema is not satisfactory, thus requiring the identification of effective agents in clinical trials. Recently, several new drugs were developed: a recombinant C1-INH, a kallikrein inhibitor (ecallantide) and a specific bradykinin-B2-receptor antagonist (icatibant). According to currently available reports, these drugs may improve the treatment of kinin-induced angioedema.
Composite scaffolds can improve regenerative capacities of scaffolds in various tissue-engineering approaches. In order to generate a 3D printable scaffold that is capable of cartilage regeneration, ...decellularized extracellular matrix (DECM) of porcine nasal cartilage was added to 3D printed polycaprolactone (PCL) scaffolds. Subsequently, scaffolds (PCL, PCL/DECM and DECM) were seeded with human primary nasoseptal chondrocytes and differentiated with cartilage inductive medium for up to 42 days in vitro. Afterwards samples were analyzed with scanning electron microscopy, histology, biochemical assays and gene expression analysis. In short, results showed cell attachment and proliferation on all scaffolds. There was a trend towards ossification on pure PCL scaffolds, whereas we found evidence for cartilage tissue formation on DECM scaffolds as well as on PCL/DECM scaffolds. Moreover, biochemical analysis indicated an enhanced differentiation on novel PCL/DECM scaffolds. In conclusion, the addition of DECM to 3D printable PCL scaffolds may yield a new composite material for regenerative approaches in cartilage for facial reconstructive surgery. Further research will be necessary to evaluate these findings in vivo.
Background and Objective
Matrix metalloproteinase‐8 (MMP‐8) is involved in a wide range of pathologies including periodontitis and cardiovascular diseases (CVD). The association between periodontitis ...and CVD has been repeatedly recognized. The aim of the study was to analyze to what extent circulating active MMP‐8 (aMMP‐8) is associated with periodontal disease status and oral fluid aMMP‐8 levels in otherwise healthy subjects.
Material and Methods
In a cross‐sectional study, aMMP‐8 was measured in serum of 59 volunteers, comprising 19 periodontally healthy subjects, 20 patients with gingivitis as well as 20 with periodontitis. All study subjects were characterized regarding aMMP‐8 concentrations in different oral fluids as well as clinically and microbiologically with respect to periodontal disease. aMMP‐8 levels in gingival crevicular fluid were measured using the enzyme‐linked immunosorbent assay. Saliva enzyme levels as well as circulating aMMP‐8 were determined by a time‐resolved immunofluorometric assay. Both methods utilized the same monoclonal antibodies. Correlation and regression analyses were performed to study the potential association between serum aMMP‐8 and oral parameters.
Results
Oral aMMP‐8 levels were significantly higher in patients with periodontitis compared to periodontally healthy or gingivitis subjects. Highest serum aMMP‐8 concentration was also found in the periodontitis group. The serum levels correlated significantly with oral aMMP‐8 as well as with clinical parameters in a dose‐dependent manner. These results were confirmed in a multivariate regression analysis. After adjusting for potential confounders, saliva aMMP‐8 concentrations as well as periodontitis severity were significant predictors of serum aMMP‐8.
Conclusion
The associations between circulating aMMP‐8 and oral aMMP‐8 as well as periodontal findings in a dose‐dependent manner may contribute to linking periodontal disease with increased CVDsusceptibility.
Context. Extreme ultraviolet (EUV) and X-ray radiation emitted from wind-embedded shocks in hot, massive stars can affect the ionization balance in their outer atmospheres and can be the mechanism ...responsible for producing highly ionized atomic species detected in stellar wind UV spectra. Aims. To allow for these processes in the context of spectral analysis, we have implemented the emission from wind-embedded shocks and related physics into our unified, NLTE model atmosphere/spectrum synthesis code FASTWIND. Methods. The shock structure and corresponding emission is calculated as a function of user-supplied parameters (volume filling factor, radial stratification of shock strength, and radial onset of emission). We account for a temperature and density stratification inside the postshock cooling zones, calculated for radiative and adiabatic cooling in the inner and outer wind, respectively. The high-energy absorption of the cool wind is considered by adding important K-shell opacities, and corresponding Auger ionization rates have been included in the NLTE network. To test our implementation and to check the resulting effects, we calculated a comprehensive model grid with a variety of X-ray emission parameters. Results. We tested and verified our implementation carefully against corresponding results from various alternative model atmosphere codes, and studied the effects from shock emission for important ions from He, C, N, O, Si, and P. Surprisingly, dielectronic recombination turned out to play an essential role for the ionization balance of Oiv/Ov (particularly in dwarfs with T sub(eff)~ 45000 K). Finally, we investigated the frequency dependence and radial behavior of the mass absorption coefficient, kappanu(r), which is important in the context of X-ray line formation in massive star winds. Conclusions. In almost all of the cases considered, direct ionization is of major influence because of the enhanced EUV radiation field, and Auger ionization only affects Nvi and Ovi significantly. The approximation of a radially constant kappanu is justified for r? 1.2 R sub(?) and lambda? 18 A and also for many models at longer wavelengths. To estimate the actual value of this quantity, however, the Heii opacities need to be calculated from detailed NLTE modeling, at least for wavelengths longer than 18 to 20 A, and information on the individual CNO abundances has to be present.
Context. The determination of chemical abundances constitutes a fundamental requirement for obtaining a complete picture of a star. Particularly in massive stars, CNO abundances are of prime ...interest, due to the nuclear CNO-cycle, and various mixing processes which bring these elements to the surface. The precise determination of carbon abundances, together with N and O, is thus a key ingredient for understanding the different phases of stellar evolution. Aims. We aim to enable a reliable carbon spectroscopy for our unified non-LTE atmosphere code FASTWIND. Methods. We have developed a new carbon model atom including C II/III/IV/V, and we discuss specific problems related to carbon spectroscopy in O-type stars. We describe different tests we have performed to examine the reliability of our implementation, and investigate which mechanisms influence the carbon ionization balance. By comparing with high-resolution spectra from six O-type stars, we verified to what extent observational constraints can be reproduced by our new carbon line synthesis. Results. Carbon lines are even more sensitive to a variation of Teff, log g, and Ṁ, than hydrogen and helium lines. We are able to reproduce most of the observed lines from our stellar sample, and to estimate those specific carbon abundances which bring the lines from different ions into agreement (three stages in parallel for cool objects, two for intermediate O-types). For hot dwarfs and supergiants earlier than O7, X-rays from wind-embedded shocks can have an impact on the synthesized line strengths, particularly for C IV, potentially affecting the abundance determination. Dielectronic recombination has a significant impact on the ionization balance in the wind. Conclusions. We demonstrate our capability to derive realistic carbon abundances by means of FASTWIND, using our recently developed model atom. We find that complex effects can have a strong influence on the carbon ionization balance in hot stars. For a further understanding, the UV range needs to be explored as well. By means of detailed and available nitrogen and oxygen model atoms, we will be able to perform a complete CNO abundance analysis for larger samples of massive stars, and to provide constraints on corresponding evolutionary models and aspects.
Abstract
To evaluate the suitability of volume index measurement (VI) by either ultrasound (US) or computed tomography (CT) for the assessment of liver volume. Fifty-nine patients, 21 women, with a ...mean age of 66.8 ± 12.6 years underwent US of the liver followed immediately by abdominal CT. In US and CT imaging dorsoventral, mediolateral and craniocaudal liver diameters in their maximum extensions were assessed by two observers. VI was calculated by multiplication of the diameters divided by a constant (3.6). The liver volume determined by a manual segmentation in CT (“true liver volume”) served as gold standard. True liver volume and calculated VI determined by US and CT were compared using Bland–Altman analysis. Mean differences of VI between observers were − 34.7% (− 90.1%; 20.7%) for the US-based and 1.1% (− 16.1%; 18.2%) for the CT-based technique, respectively. Liver volumes determined by semi-automated segmentation, US-based VI and CT-based VI, were as follows: 1.500 ± 347cm
3
; 863 ± 371cm
3
; 1.509 ± 432cm
3
. Results showed a great discrepancy between US-based VI and true liver volume with a mean bias of 58.3 ± 66.9%, and high agreement between CT-based VI and true liver volume with a low mean difference of 4.4 ± 28.3%. Volume index based on CT diameters is a reliable, fast and simple approach for estimating liver volume and can therefore be recommended for clinical practice. The usage of US-based volume index for assessment of liver volume should not be used due to its low accuracy of US in measurement of liver diameters.
This paper introduces a generative model for 3D surfaces based on a representation of shapes with mean curvature and metric, which are invariant under rigid transformation. Hence, compared with ...existing 3D machine learning frameworks, our model substantially reduces the influence of translation and rotation. In addition, the local structure of shapes will be more precisely captured, since the curvature is explicitly encoded in our model. Specifically, every surface is first conformally mapped to a canonical domain, such as a unit disk or a unit sphere. Then, it is represented by two functions: the mean curvature half‐density and the vertex density, over this canonical domain. Assuming that input shapes follow a certain distribution in a latent space, we use the variational autoencoder to learn the latent space representation. After the learning, we can generate variations of shapes by randomly sampling the distribution in the latent space. Surfaces with triangular meshes can be reconstructed from the generated data by applying isotropic remeshing and spin transformation, which is given by Dirac equation. We demonstrate the effectiveness of our model on datasets of man‐made and biological shapes and compare the results with other methods.
This paper introduces a generative model for 3D surfaces based on a representation of shapes with mean curvature and metric, which are invariant under rigid transformation.
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