Ueber den Einfluss des Kauens auf die Verdauung von Nahrungsmitteln

Ohne Zusammenfassung     

Massenspektroskopie von Naturstoffen. I. Vergleichende Anionen-Kationen-Massenspektroskopie von 2,3,4,6-Tetra-O-acetyl-β-D-glucopyranosylestern

Mass Spectroscopy of Natural Compounds. I. Comparative Investigation of Anion-Cation Mass Spectra of 2,3,4,6-Tetra-O-acetyl-β-D-glucopyranosyl Esters The electron attachment mass spectra (anion mass spectra) of 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl esters with different structures of the acids are discussed and compared with the corresponding electron impact spectra. In contrast to the cation mass spectra the molecular ion peak appears in all the anion mass spectra.     

Social network architecture and the maintenance of deleterious cultural traits

How have changes in communications technology affected the way that misinformation spreads through a population and persists? To what extent do differences in the architecture of social networks affect the spread of misinformation, relative to the rates and rules by which individuals transmit or eliminate different pieces of information (cultural traits)? Here, we use analytical models and individual-based simulations to study how a ‘cultural load’ of misinformation can be maintained in a population under a balance between social transmission and selective elimination of cultural traits with low intrinsic value. While considerable research has explored how network architecture affects percolation processes, we find that the relative rates at which individuals transmit or eliminate traits can have much more profound impacts on the cultural load than differences in network architecture. In particular, the cultural load is insensitive to correlations between an individual''s network degree and rate of elimination when these quantities vary among individuals. Taken together, these results suggest that changes in communications technology may have influenced cultural evolution more strongly through changes in the amount of information flow, rather than the details of who is connected to whom.     

Laser direct writing of β-Co/Ga and Mn/Ga alloy microstructures from organometallic single-source precursors

β-Co/Ga and Mn/Ga alloys have been deposited on various substrates by laser direct write chemical vapour deposition (LCVD) from novel single-source precursors. The preformed alloy stoichiometry of 1:1 defined by the metal ratio of the precursors, (CO)₄Co-GaEt₂(NMe₃) (1) and (CO)₅Mn-GaEt₂(NMe₃) (2), is retained within the deposited structures. The depositions were up to 1.5 μm thick and the lateral dimension (4 μm) was determined by the diameter of the laser focus. The deposited structures were contaminated with ∼10 at. % C and O (by AES).     

Aurora Kinase A Is Involved in Controlling the Localization of Aquaporin-2 in Renal Principal Cells

The cAMP-dependent aquaporin-2 (AQP2) redistribution from intracellular vesicles into the plasma membrane of renal collecting duct principal cells induces water reabsorption and fine-tunes body water homeostasis. However, the mechanisms controlling the localization of AQP2 are not understood in detail. Using immortalized mouse medullary collecting duct (MCD4) and primary rat inner medullary collecting duct (IMCD) cells as model systems, we here discovered a key regulatory role of Aurora kinase A (AURKA) in the control of AQP2. The AURKA-selective inhibitor Aurora-A inhibitor I and novel derivatives as well as a structurally different inhibitor, Alisertib, prevented the cAMP-induced redistribution of AQP2. Aurora-A inhibitor I led to a depolymerization of actin stress fibers, which serve as tracks for the translocation of AQP2-bearing vesicles to the plasma membrane. The phosphorylation of cofilin-1 (CFL1) inactivates the actin-depolymerizing function of CFL1. Aurora-A inhibitor I decreased the CFL1 phosphorylation, accounting for the removal of the actin stress fibers and the inhibition of the redistribution of AQP2. Surprisingly, Alisertib caused an increase in actin stress fibers and did not affect CFL1 phosphorylation, indicating that AURKA exerts its control over AQP2 through different mechanisms. An involvement of AURKA and CFL1 in the control of the localization of AQP2 was hitherto unknown.     

Studies on the base-catalyzed Solvolysis of Propane-2-sulphonic Acid p-Cresylester

Products of the reaction of propane-2-sulphonic acid p-cresylester with sodium butoxide in butanol are the sodium salt of propan-2-sulphonic acid, di-n-butyl ether, p-cresyl-n-butyl ether and p-cresol. The reaction proceeds via propane-2-sulphonic acid n-butylester which is formed from the starting compound by an elimination-addition (sulphene) mechanism. The elimination step is an E1-cB reaction.     

Synthesis and isolation of <Emphasis Type="Italic">trans</Emphasis>-7, <Emphasis Type="Italic">cis</Emphasis>-9 octadecadienoic acid and other CLA isomers by base conjugation of partially hydrogenated γ-linolenic acid

CLA is of considerable interest because of reported potentially beneficial effects in animal studies. CLA, while not yet unambiguously defined, is a mixture of octadecadienoic acids with conjugated double bonds. The major isomer in natural products is generally considered to be cis-9,trans-11-octadecadienoic acid (c9, t11), which represents >75% of the total CLA in most cases. Other isomers are drawing increased attention. The t7,c9 isomer, which is often the second-most prevalent CLA in natural products, has been reported to represent as much as 40% of total CLA in milk from cows fed a high-fat diet. The need for a reference material became apparent in a recent study directed specifically at measuring t7,c9-CLA in milk, plasma, and rumen. A suitable standard mixture was produced by stirring 0.5 g of γ-linolenic acid (all cis-6,9, 12-C_18∶3) with 100 mL of 10% hydrazine hydrate in methanol for 2.5 h at 45°C. The solution was diluted with H₂O and acidified with HCl. The resulting partially hydrogenated FA were extracted with ether/petroleum ether, dried with Na₂SO₄, and conjugated by adding of 6.6% KOH in ethlylene glycol and heating for 1.5 h at 150–160°C. Approximately 20 mg each of cis-6, trans-8; trans-7, cis-9; cis-9, trans-11; and rans-10, cis-12 were obtained along with other FA. Methyl esters (FAME) of these four cis/trans isomers were resolved by Ag⁺HPLC (UV 233) and partially resolved by GC/(MS or FID) (CP-Sil 88). Treatment of these FAME with I₂ yielded all possible cis/trans (geometric) isomers for the four positions 6,8; 7,9; 9,11; and 10,12.     

Nanostructured Silver Substrates With Stable and Universal SERS Properties: Application to Organic Molecules and Semiconductor Nanoparticles

Nanostructured silver films have been prepared by thermal deposition on silicon, and their properties as SERS substrates investigated. The optimal conditions of the post-growth annealing of the substrates were established. Atomic force microscopy study revealed that the silver films with relatively dense and homogeneous arrays of 60–80-nm high pyramidal nanoislands are the most efficient for SERS of both organic dye and inorganic nanoparticles analytes. The noticeable enhancement of the Raman signal from colloidal nanoparticles with the help of silver island films is reported for the first time.     

基于中子成像的水泥基材料毛细吸水动力学研究

总结了国内外有关水泥基材料毛细吸水的动力学机理及其现有模型,应用中子成像技术对其毛细吸水过程进行了可视化再现,对水分侵入的空间分布规律进行了定量分析。结果表明,在毛细孔吸附力作用下,水分前锋不断向水泥基材料内部推进,在吸水初期速度较快,后趋于平缓直至稳定;水分侵入曲线在深度和含量上同时增 长,可以由线性+反S形模型来描述其空间分布特点,并与实测结果吻合良好;现有的 “时间开方” 及其修正模型对毛细吸水的后期预测不太合理,本文提出的渗透系数双曲线衰减模型更符合真实结果。