1,761 research outputs found
Theoretical study on isomerization of α-acids: A DFT calculation
The α-acids contained in hops are one of the ingredients of beer. The isomerization of α-acids produces iso-α-acids, the main source of bitterness in beer. In this study, the isomerization mechanism of the α-acid, cohumulone, was elucidated by using density functional theory in conjunction with the polarizable continuum model or 3D-RISM integral equation theory of liquids. The calculated reaction diagram is consistent with experimental results; the activation free energy difference between the cis and trans isomers is in good agreement with the experimental estimate. The activation energy difference results from solvation energy. Additionally, a calculation of NMR chemical shifts showed that the proton position of isocohumulone is different from that proposed previously. The effect of Mg²⁺ cation on the isomerization was also investigated. Both the activation and reaction free energy are stabilized by the presence of Mg²⁺, which is consistent with experimental results. Water solvation reduces the activation free energy
Local SiC photoluminescence evidence of non-mutualistic hot spot formation and sub-THz coherent emission from a rectangular BiSrCaCuO mesa
From the photoluminescence of SiC microcrystals uniformly covering a
rectangular mesa of the high transition temperature superconductor
BiSrCaCuO, the local surface temperature
was directly measured during simultaneous sub-THz emission from the
intrinsic Josephson junctions (IJJs) in the mesa. At high bias currents and
low bath temperatures K, the center of a large
elliptical hot spot with jumps dramatically with little
current-voltage characteristic changes. The hot spot doesn't alter the
ubiquitous primary and secondary emission conditions: the ac Josephson relation
and the electromagnetic cavity resonance excitation, respectively. Since the
intense sub-THz emission was observed for high K in
the low bias regime where hot spots are absent, hot spots can not provide
the primary mechanisms for increasing the output power, the tunability, or for
promoting the synchronization of the IJJs for the sub-THz emission, but can
at best coexist non-mutualistically with the emission. No standing
waves were observed
Hautgeschwulste durch Lungendistoma (Paragonimus westermani)
Zwei 7 jahrige Kinder nahmen ungekochte Flussigkeit von Potamon dehaanii zu sich, eine Volksrnedizin gegen Keuchhusten. Einige Monate darauf bemerkten sie blutige Sputa und nicht entzundliche Geschwulste an den Lenden oder der Bauchseite. In den Tumoren wurde je ein Lungendistoma entdeckt. Dieser Parasit kann daher manchmal in die Subkutis oder in die tiefe Kutisschicht einwandern. Zum Schlusse Inochten wir Herrn Prof. Tanabe vom pathologischen Institut dieser Universitat unsern warmsten Dank aussprechen dafur, dass er die Struktur der Parasiten eingehend untersuchte. </p
Treatment of mandibular condyalr osteochondroma
We successfully treated a case of facial asymmetry involved in unilateral mandibular condylar osteochondroma with ipsilateral mandibular condylectomy and contralateral ramus osteotomy. A female, 32-year 11-month of age, had a chief complaint of facial asymmetry which initiated about 10 years ago. A mirror image analysis using a non-contact 3D image scanner revealed that the soft tissue on the deviated side was protruded more than 5.50 mm compared with the non-deviated side. The patinet was diagnosed as facial asymmetry with a skeletal Class III jaw-base relationship caused by unilateral mandibular condylar osteochondroma. After 18 months of preoperative orthodontic treatment, ipsilateral condylectomy and contralateral sagittal split ramus osteotomy were performed. As the results of postoperative orthodontic treatment for 20 months, an ideal occlusion having a Class I molar relationship with an adequate interincisal relationship was achieved. Facial asymmetry and mandibular protrusion were dramatically improved, and the differences between the deviation and non-deviation sides were decreased to less than 1.11 mm. The acceptable occlusion and symmetric face were maintained throughout 1-year retention period. Conclusively, our results indicated the stability after condylectomy without condylar reconstruction in a patient with unilateral condylar osteochondroma
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