Micellar Catalysis and Concept in Apolar Media

The active interest aroused by catalytically affected reactions in apolar surfactant solutions requires one to look for a relation to micelle formation and solubilization in an effort to attain a more unified description of phenomena peculiar to apolar surfactant systems. Since these catalytic phenomena are usually summarized by the notion »micellar catalysis« the present paper wants to contribute towards a sound abstraction of this concept. This was done by analyzing a particular catalyzed reaction (the catalyzed hydrolysis of p-nitrophenylacetate in the presence of dodecylammoniumpropionate in cyclohexane) in the frequently investigated apolar solutions of cationic surfactants. A quantitative description of the overall reaction was obtained which was found in satisfactory agreement with experimental details. It was concluded that micellar and multiple association patterns are reflected also in the relationships obtained by examining catalytically influenced reactions in these systems

Electron Microscopy Of Wood Of Callixylon And Cordaites

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141638/1/ajb210693.pd

Metabolomic Profiling Reveals Distinct and Mutual Effects of Diet and Inflammation in Shaping Systemic Metabolism in Ldlr(-/-) Mice

Changes in modern dietary habits such as consumption of Western-type diets affect physiology on several levels, including metabolism and inflammation. It is currently unclear whether changes in systemic metabolism due to dietary interventions are long-lasting and affect acute inflammatory processes. Here, we investigated how high-fat diet (HFD) feeding altered systemic metabolism and the metabolomic response to inflammatory stimuli. We conducted metabolomic profiling of sera collected from Ldlr(-/-) mice on either regular chow diet (CD) or HFD, and after an additional low-dose lipopolysaccharide (LPS) challenge. HFD feeding, as well as LPS treatment, elicited pronounced metabolic changes. HFD qualitatively altered the systemic metabolic response to LPS; particularly, serum concentrations of fatty acids and their metabolites varied between LPS-challenged mice on HFD or CD, respectively. To investigate whether systemic metabolic changes were sustained long-term, mice fed HFD were shifted back to CD after four weeks (HFD \u3e CD). When shifted back to CD, serum metabolites returned to baseline levels, and so did the response to LPS. Our results imply that systemic metabolism rapidly adapts to dietary changes. The profound systemic metabolic rewiring observed in response to diet might affect immune cell reprogramming and inflammatory responses

Thermal stability of internal gettering of iron in silicon and its impact on optimization of gettering

The redissolution behavior of gettered iron was studied in p-type Czochralski-grown silicon with a doping level of 2.5×10exp14 cm−3 and an oxide precipitate density of 5×10exp9 cm−3. The concentrations of interstitial iron and iron–boron pairs were measured by deep level transient spectroscopy. It was found that the dependence of redissolved iron concentration on annealing time can be fitted by the function C(t)=C_0[1−exp(−t/tau_diss)], and the dissolution rate tau−1diss has an Arrhenius-type temperature dependence of tau−1diss=4.01×10exp4 × exp[−(1.47±0.10) eV/k_BT] s−1. Based on this empirical equation, we predict how stable the gettered iron is during different annealing sequences and discuss implications for optimization of internal gettering.Peer reviewe

Depth profile analyses of films grown at different temperatures

Cu(In,Ga)Se2films are used as absorber layers in chalcopyrite thin filmsolar cells. As the gallium concentration in the absorber can be used to control the band gap, there have been many efforts to vary the gallium concentration in depth to gain an optimum balance of light absorption, carrier collection, and recombination at different depths of the absorber film, leading to improved quantum efficiency. In this study, we investigate the effect of the maximum substrate temperature during film growth on the depth dependent gallium concentration. For the in-depth gallium concentration analyses, we use two techniques, covering complementary depth ranges. Angle dependent soft x-ray emission spectroscopy provides access to information depths between 20 and 470 nm, which covers the depth range of the space charge region, where most of the photoexcited carriers are generated. Therefore, this depth range is of particular interest. To complement this investigation we use secondary neutral mass spectrometry, which destructively probes the whole thickness of the absorber (≈2 μm). The two methods show increasingly pronounced gallium and indium gradients with decreasing maximum substrate temperature. The probing of the complementary depth ranges of the absorbers gives a consistent picture of the in-depth gallium distribution, which provides a solid basis for a comprehensive discussion about the effect of a reduced substrate temperature on the formation of gallium gradients in Cu(In,Ga)Se2 and the device performance of the corresponding reference solar cells

Higher Order Effects in the Dielectric Constant of Percolative Metal-Insulator Systems above the Critical Point

The dielectric constant of a conductor-insulator mixture shows a pronounced maximum above the critical volume concentration. Further experimental evidence is presented as well as a theoretical consideration based on a phenomenological equation. Explicit expressions are given for the position of the maximum in terms of scaling parameters and the (complex) conductances of the conductor and insulator. In order to fit some of the data, a volume fraction dependent expression for the conductivity of the more highly conductive component is introduced.Comment: 4 pages, Latex, 4 postscript (*.epsi) files submitted to Phys Rev.

Charcot-Leyden Crystals activate the NLRP3 inflammasome and cause IL-1β inflammation [preprint]

Charcot-Leyden crystals (CLCs) are Galectin-10 protein crystals that can form after eosinophils degranule. CLCs can appear and persist in tissues from patients with eosinophilic disorders, such as asthma, allergic reactions, fungal, and helminthic infections. Despite abundant reports of their occurrence in human disease, the inflammatory potential of CLCs has remained unknown. Here we show that CLCs induce IL-1β release upon their uptake by primary human macrophages in vitro, and that they induce inflammation in vivo in mouse models of acute peritonitis and bronchitis. CLC-induced IL-1β was dependent on NLRP3 and caspase-1, and their instillation in inflammasome reporter mice promoted the assembly of ASC complexes and IL-1β secretion in the lungs. Our findings reveal that CLCs are recognized by the NLRP3 inflammasome, which may sustain inflammation that follows eosinophilic inflammatory processes

Importance of extra- and intracellular domains of TLR1 and TLR2 in NFkappa B signaling

Recognition of ligands by toll-like receptor (TLR) 2 requires interactions with other TLRs. TLRs form a combinatorial repertoire to discriminate between the diverse microbial ligands. Diversity results from extracellular and intracellular interactions of different TLRs. This paper demonstrates that TLR1 and TLR2 are required for ara-lipoarabinomannan- and tripalmitoyl cysteinyl lipopeptide-stimulated cytokine secretion from mononuclear cells. Confocal microscopy revealed that TLR1 and TLR2 cotranslationally form heterodimeric complexes on the cell surface and in the cytosol. Simultaneous cross-linking of both receptors resulted in ligand-independent signal transduction. Using chimeric TLRs, we found that expression of the extracellular domains along with simultaneous expression of the intracellular domains of both TLRs was necessary to achieve functional signaling. The domains from each receptor did not need to be contained within a single contiguous protein. Chimeric TLR analysis further defined the toll/IL-1R domains as the area of crucial intracellular TLR1-TLR2 interaction

Resolution of Racemic Guaifenesin Applying a Coupled Preferential Crystallization-Selective Dissolution Process: Rational Process Development

Preferential crystallization is a cost efficient method to provide pure enantiomers from a racemic mixture of a conglomerate forming system. Exploiting small amounts of pure crystals of both enantiomers, several batch or continuous processes were developed, capable of providing both species. However, an intermediate production step has to be used when pure enantiomers are not available. In such cases, partially selective synthesis, chromatography, or crystallization processes utilizing chiral auxiliaries have to be used to provide the initial seed material. Recently, it was shown that a coupled Preferential Crystallization-selective Dissolution process (CPCD) in two coupled crystallizers can be applied if at least one pure enantiomer is available to produce both antipodes within one batch. The corresponding process is carried out in one reactor (crystallization tank) by seeding a racemic supersaturated solution with the available enantiomer at a certain temperature. The second reactor (dissolution tank) contains a saturated racemic suspension at a higher temperature. Both reactors are coupled via the fluid phase, allowing for a selective dissolution of the preferentially crystallizing enantiomer from the solid racemic feed provided in the dissolution vessel. The dissolution and crystallization processes continue until the solid racemic material is completely resolved and becomes enantiopure. At this point, both enantiomers can be harvested in their pure crystalline form. For a specific pharmaceutically relevant case study, a rational process design and the applied empirical optimization procedure will be described. The achieved productivities after optimization show the great potential of this approach also for industrial applications. Also, a strategy to control this process based on inline turbidity measurement will be presented