Conformational space of cinchonidine has been explored by means of ab initio potential and free energy surfaces, and the temperature-induced changes of conformational populations were studied by a combined NOESY-DFT analysis. The DFT-derived potential energy surface investigation identified four new conformers. Among them, Closed(7) is substantially relevant to fully understand the conformational behavior. The energy surfaces gave access to the favored transformation pathways at different temperatures (280-320 K). They also revealed the reasons for the negligible presence of energetically stable conformers and explained the experimentally observed temperature dependence of the populations.

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PURPOSE: Hypoxia has been shown to reduce energy intake and lead to weight loss, but the underlying mechanisms are unclear. The aim was therefore to assess changes in eating after rapid ascent to 4,559 m and to investigate to what extent hypoxia, acute mountain sickness (AMS), food preferences and satiation hormones influence eating behavior. METHODS: Participants (n = 23) were studied at near sea level (Zurich (ZH), 446 m) and on two days after rapid ascent to Capanna Margherita (MG) at 4,559 m (MG2 and MG4). Changes in appetite, food preferences and energy intake in an ad libitum meal were assessed. Plasma concentrations of cholecystokinin, peptide tyrosine-tyrosine, gastrin, glucagon and amylin were measured. Peripheral oxygen saturation (SpO(2)) was monitored, and AMS assessed using the Lake Louis score. RESULTS: Energy intake from the ad libitum meal was reduced on MG2 compared to ZH (643 ± 308 vs. 952 ± 458 kcal, p = 0.001), but was similar to ZH on MG4 (890 ± 298 kcal). Energy intake on all test days was correlated with hunger/satiety scores prior to the meal and AMS scores on MG2 but not with SpO(2) on any of the 3 days. Liking for high-fat foods before a meal predicted subsequent energy intake on all days. None of the satiation hormones showed significant differences between the 3 days. CONCLUSION: Reduced energy intake after rapid ascent to high altitude is associated with AMS severity. This effect was not directly associated with hypoxia or changes in gastrointestinal hormones. Other peripheral and central factors appear to reduce food intake at high altitude. DOI: https://doi.org/10.1007/s00394-012-0366-9Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-62402 Accepted Version Originally published at: Aeberli, Isabelle; Erb, Annina; Spliethoff, Kerstin; Meier, Daniela; Götze, Oliver; Frühauf, Heiko; Fox, Mark; Finlayson, Graham S; Gassmann, Max; Berneis, Kaspar; Maggiorini, Marco; Langhans, Wolfgang; Lutz, Thomas A (2013). Disturbed eating at high altitude: influence of food preferences, acute mountain sickness and satiation hormones. European Journal of Nutrition, 52 (2) Purpose Hypoxia has been shown to reduce energy intake and lead to weight loss, 36 but the underlying mechanisms are unclear. The aim was therefore, to assess 37 changes in eating after rapid ascent to 4559 m and to investigate to what extent 38 hypoxia, acute mountain sickness (AMS), food preferences, and satiation hormones 39 influence eating behavior. 40Methods Participants (n=23) were studied at near sea level (Zurich (ZH), 446 m) and 41 on two days after rapid ascent to Capanna Margherita (MG) at 4559 m (MG2 and 42 MG4). Changes in appetite, food preferences and energy intake in an ad libitum meal 43were assessed. Plasma concentrations of cholecystokinin, peptide tyrosine-tyrosine, 44 gastrin, glucagon and amylin were measured. Peripheral oxygen saturation (SpO2) 45 was monitored and AMS assessed using the Lake Louis score. 46Results Energy intake from the ad...

Cinnamyl alcohol was oxidized to cinnamaldehyde in a continuous fixed-bed reactor with molecular oxygen over an alumina-supported palladium catalyst in supercritical carbon dioxide modified with toluene. A strong dependence of the reaction performance on pressure and oxygen concentration in the feed was found. Optimization of the reaction conditions resulted in a higher catalytic activity than in liquid phase. At 120 bar, 80 °C, and double stoichiometric oxygen concentration, a turnover frequency of 400 h-1 at a selectivity of 60% to cinnamaldehyde was achieved. Spectroscopic investigations and the knowledge of the selectivity pattern turned out to be crucial for a deeper understanding of the reaction allowing a rational optimization. Under almost all experimental conditions (even at high oxygen concentration) hydrogenated byproducts, stemming from internal hydrogen transfer reactions, were detected in the effluent. This indicated that alcohol dehydrogenation is the first reaction step, further confirmed by spectroscopic investigations. In situ XANES and EXAFS uncovered that in the whole experimental range investigated the palladium constituent was mainly in a reduced state and that its surface could be oxidized only in the absence of cinnamyl alcohol in the feed. Bulk phase behaviour studies and investigations at the catalyst/fluid interface, performed by visual inspection and combined transmission and ATR-IR spectroscopy, uncovered that the reaction performed best in the biphasic region. Moreover, cinnamaldehyde and carbon dioxide but hardly any toluene and cinnamyl alcohol were detected inside the porous catalyst, evidencing a strongly different product composition inside the porous catalyst compared to the bulk phase.

Polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS), facilitating simultaneous selective detection of liquid phase and surface bound species, was applied to study the liquid-phase oxidation of benzyl alcohol to benzaldehyde on a Pd film. Experiments under aerobic and anaerobic conditions revealed significantly higher activity under anaerobic conditions and higher selectivity under aerobic conditions. Under anaerobic conditions toluene was the major side product. CO 2 and benzoic acid, not yet detected by in situ IR during this reaction, were observed as degradation and side products in the liquid phase. Enhanced formation of CO 2 and benzoic acid was observed under aerobic conditions where no surface signals could be detected. In contrast, under anaerobic conditions CO formed by decarbonylation of benzaldehyde was observed on the Pd (111) surface, delayed with respect to the formation profile of benzaldehyde in the liquid phase. Both CO and oxygen were found to poison the surface for alcohol oxidation. The poisoning by oxygen was more effectual than that by CO, which was attributed to the low surface area of the Pd film as well as the nonsite-selective nature of the alcohol oxidation. No benzoate species were present on the Pd surface. This confirmed the hypothesis that benzoate species only adsorb on the basic support sites and not on Pd.

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This study reports how extracellular matrix (ECM) ligand self-assembly on biomaterial surfaces and the resulting nanoscale architecture can drive stem cell behavior. To isolate the biological effects of surface wettability on protein deposition, folding, and ligand activity, a polydimethylsiloxane (PDMS)-based platform was developed and characterized with the ability to tune wettability of elastomeric substrates with otherwise equivalent topology, ligand loading, and mechanical properties. Using this platform, markedly different assembly of covalently bound type I collagen monomers was observed depending on wettability, with hydrophobic substrates yielding a relatively rough layer of collagen aggregates compared to a smooth collagen layer on more hydrophilic substrates. Cellular and molecular investigations with human bone marrow stromal cells revealed higher osteogenic differentiation and upregulation of focal adhesion-related components on the resulting smooth collagen layer coated substrates. The initial collagen assembly driven by the PDMS surface directly affected α1β1 integrin/discoidin domain receptor 1 signaling, activation of the extracellular signal-regulated kinase/mitogen activated protein kinase pathway, and ultimately markers of osteogenic stem cell differentiation. We demonstrate for the first time that surface-driven ligand assembly on material surfaces, even on materials with otherwise identical starting topographies and mechanical properties, can dominate the biomaterial surface-driven cell response.

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