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1,175 results on '"Hiller, W."'

5. Debye relaxation and 250 K anomaly in glass forming monohydroxy alcohols

Author

Bauer, S., Burlafinger, K., Gainaru, C., Lunkenheimer, P., Hiller, W., Loidl, A., and Böhmer, R.

Subjects
Physics - Chemical Physics, Condensed Matter - Materials Science
Abstract

A previous dielectric, near-infrared (NIR), and nuclear magnetic resonance study on the hydrogen-bonded liquid 2-ethyl-1-hexanol [C. Gainaru et al., Phys. Rev. Lett. 107, 118304 (2011)] revealed anomalous behavior in various static quantities near 250 K. To check whether corresponding observations can be made for other monohydroxy alcohols as well, these experimental methods were applied to such substances with 5, 6, 7, 8, and 10 carbon atoms in their molecular backbone. All studied liquids exhibit a change of behavior near 250 K which is tentatively ascribed to effects of hydrogen bond cooperativity. By analyzing the NIR band intensities, a linear cluster size is derived that agrees with estimates from dielectric spectroscopy. All studied alcohols, except 4-methyl-3-heptanol, display a dominant Debye-like peak. Furthermore, neat 2-ethyl-1-butanol exhibits a well resolved structural relaxation in its dielectric loss spectrum which so far has only been observed for diluted monohydroxy alcohols., Comment: 39 pages including 12 figures

Published
2013
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6. Hydrogen-bond equilibria and life times in a supercooled monohydroxy alcohol

Author

Gainaru, C., Kastner, S., Mayr, F., Lunkenheimer, P., Schildmann, S., Weber, H. J., Hiller, W., Loidl, A., and Böhmer, R.

Subjects
Condensed Matter - Soft Condensed Matter
Abstract

Dielectric loss spectra covering 13 decades in frequency were collected for 2-ethyl-1-hexanol, a monohydroxy alcohol that exhibits a prominent Debye-like relaxation, typical for several classes of hydrogen-bonded liquids. The thermal variation of the dielectric absorption amplitude agrees well with that of the hydrogen-bond equilibrium population, experimentally mapped out using near infrared (NIR) and nuclear magnetic resonance (NMR) measurements. Despite this agreement, temperature-jump NIR spectroscopy reveals that the hydrogen-bond switching rate does not define the frequency position of the prominent absorption peak. This contrasts with widespread notions and models based thereon, but is consistent with a recent approach., Comment: 4 pages, 4 figures

Published
2011
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7. Nuclear magnetic resonance measurements reveal the origin of the Debye process in monohydroxy alcohols

Author

Gainaru, C., Meier, R., Schildmann, S., Lederle, C., Hiller, W., Rössler, E. A., and Böhmer, R.

Subjects
Condensed Matter - Soft Condensed Matter
Abstract

Monohydroxy alcohols show a structural relaxation and at longer time scales a Debye-type dielectric peak. From spin-lattice relaxation experiments using different nuclear probes an intermediate, slower-than-structural dynamics is identified for n-butanol. Based on these findings and on diffusion measurements, a model of self-restructuring, transient chains is proposed. The model is demonstrated to explain consistently the so far puzzling observations made for this class of hydrogen-bonded glass forming liquids., Comment: 4 pages, 4 figures

Published
2010
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8. Modul 3: Aufmerksamkeit

Author

Kleinstäuber, M., Thomas, P., Witthöft, M., Hiller, W., Kleinstäuber, Maria, Thomas, Petra, Witthöft, Michael, and Hiller, Wolfgang

Published
2018
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9. Modul 7: Störungsmodell

Author

Kleinstäuber, M., Thomas, P., Witthöft, M., Hiller, W., Kleinstäuber, Maria, Thomas, Petra, Witthöft, Michael, and Hiller, Wolfgang

Published
2018
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28. Clinical presentation of exercise‐associated hyponatremia in male and female IRONMAN® triathletes over three decades.

Author

Johnson, Kasey B., Connolly, Christopher P., Cho, Stephanie P., Miller, Thomas K., Sallis, Robert E., and Hiller, W. Douglas B.

Subjects
SODIUM, MEN, WOMEN, ACQUISITION of data, HYPONATREMIA, COMPARATIVE studies, EXERCISE, TRIATHLON, ENDURANCE sports, MEDICAL records, DESCRIPTIVE statistics, ATHLETIC ability, SPORTS events, ELECTRONIC health records, LOGISTIC regression analysis
Abstract

Purpose: Exercise‐associated hyponatremia (EAH) is common in ultra‐endurance events and severe cases are more common in females. The purpose of this paper is to compare the clinical presentation of EAH between male and female triathletes in ultra‐endurance competitions. Methods: Medical records with sodium concentrations (n = 3138) from the IRONMAN® World Championships over the timeframe of 1989–2019 were reviewed for both male (n = 2253) and female (n = 885) competitors. Logistic regression was used to explore the relationships between sex, sodium concentration, and various clinical presentations. Results: When comparing male and female triathletes, clinical variables found to have a different relationship with sodium concentration include altered mental status (inversely related in males and not related in females), abdominal pain, muscle cramps, hypotension, and tachycardia (directly related in males and not related in females), and vomiting and hypokalemia (not related in males and inversely related in females). Overall, males lost significantly more weight than females, and notably, approximately half of all athletes were dehydrated and lost weight. Conclusions: Altered mental status, vomiting, abdominal pain, muscle cramps, hypotension, tachycardia, and hyperkalemia appear to present differently between sexes when comparing hyponatremic to eunatremic athletes. Although overhydration is the most common etiology of hypervolemic hyponatremia, hypovolemic hyponatremia comprises a significant amount of hyponatremic triathletes. Further understanding of how EAH presents helps athletes and medical professionals identify it early and prevent life‐threatening complications. [ABSTRACT FROM AUTHOR]

Published
2023
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41. Structure and dynamics of short-chain polymerized ionic liquids.

Author

Wieland, F., Bocharova, V., Münzner, P., Hiller, W., Sakrowski, R., Sternemann, C., Böhmer, R., Sokolov, A. P., and Gainaru, C.

Subjects
POLYMERIZED ionic liquids, DIFFUSION, DYNAMICS, NUCLEAR magnetic resonance, DIFFUSION coefficients, TETRAFLUOROBORATES
Abstract

Combining experimental results obtained with X-ray scattering and field-gradient nuclear magnetic resonance (NMR) and an assessment of new and previous dielectric and rheology data, our study focuses on the molecular weight (Mw) evolution of local structure and dynamics in a homologous series of covalently bonded ionic liquids. Performed on a family of electrolytes with a tailored degree of ionic decoupling, this study reveals the differences between monomeric and oligomeric melts with respect to their structural organization, mass and charge transport, and molecular diffusion. Our study demonstrates that for the monomeric compound, the broadband conductivity and mechanical spectra reflect the same underlying distribution of activation barriers and that the Random Barrier Model describes fairly well both the ionic and structural relaxation processes in these materials. Moreover, the oligomers with chains comprising ten segments only exhibit both structural and dynamical fingerprints of a genuine polymer. A comparison of conductivity levels estimated using the self-diffusion coefficients probed via NMR and those probed directly with dielectric spectroscopy reveals the emerging of ion correlations which are affecting the macroscopic charge transport in these materials in a chain-length dependent manner. [ABSTRACT FROM AUTHOR]

Published
2019
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42. The Social Phobia Psychotherapy Research Network : The First Multicenter Randomized Controlled Trial of Psychotherapy for Social Phobia: Rationale, Methods and Patient Characteristics

Author

Leichsenring, F., Hoyer, J., Beutel, M., Herpertz, S., Hiller, W., Irle, E., Joraschky, P., König, H.H., de Liz, T.M., Nolting, B., Pöhlmann, K., Salzer, S., Schauenburg, H., Stangier, U., Strauss, B., Subic-Wrana, C., Vormfelde, S., Weniger, G., Willutzki, U., Wiltink, J., and Leibing, E.

Published
2009

46. Innenohr II: Hörsturz/Tinnitus

Author

Korves, B., Wolf, S., Klimek, L., Lamprecht, J., Hagen, R., Kraus, P., Utz, A., Frömel, J., Desloovere, C., Knecht, R., Rosemann, B., Schmidt, R., Bömer, D., Hoffmann, G., Böckler, B., Scheibe, F., Haupt, H., Ludwig, C., Lutz, H., Jahnke, K., Höhmann, D., Philipp, A., Brassel, F., Goebel, G., Hiller, W., Feldmann, Harald, and Herberhold, Claus

Published
1993
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