Authors' reply

Upper and lower bounds are given for the lowest frequencies of vibration of clamped rhombical plates. These bounds were obtained by using a recently developed method which allows the use of trial functions which do not need to satisfy any boundary conditions.     

Apparent Production of Enzymatically Synthesized Amylose in DMSO by Means of Calcium Alginate Hydrogel Beads/DMSO System

In this paper, we describe the apparent production of enzymatically synthesized amylose in DMSO by means of the calcium alginate hydrogel beads/DMSO system as the reaction field of the phosphorylase-catalyzed enzymatic polymerization. When the calcium alginate hydrogel beads including glucose-1-phosphate, maltoheptaose, and phosphorylase were suspended in DMSO and the system was slowly stirred at 40°C for 12 h, the reaction proceeded to produce amylose, which eluted to the DMSO solution. The obtained amylose was purified by the treatment with ion-exchange resins, and its structure was confirmed by the ¹H NMR spectrum. The time-course experiment in the present system revealed that the phosphorylase-catalyzed enzymatic polymerization was carried out for 15 min on the inside of the calcium alginate hydrogel beads and the produced amylose was gradually eluted to the surrounding DMSO solution. The comparison of the present system with the general enzymatic polymerization in aqueous buffer solution suggested that the yield and the degree of polymerization of amylose in the present system were comparable to those in aqueous buffer solution.     

Photochromism of bis(2-alkyl-1-benzofuran-3-yl)perfluorocyclopentene derivatives

[reaction: see text] Photochromic diarylethene derivatives having benzofuran heteroaryl groups, bis(2-methyl-1-benzofuran-3-yl)perfluorocyclopentene and bis(2-butyl-1-benzofuran-3-yl)perfluorocyclopentene, were synthesized, and their photochromic performance was examined in hexane solution as well as in the single-crystalline phase. The compounds exhibited photochromic reactivity even in the single-crystalline phase.     

Crystal structure-reactivity correlation in single-crystalline photochromism of 1,2-bis(2-methyl-5-phenyl-3-thienyl)perfluorocyclopentene

Single-crystalline photochromism of 1,2-bis(2-methyl-5-phenyl-3-thienyl)perfluorocyclopentene 1a was followed in situ by X-ray crystallographic analysis. The crystal of 1a has two molecules with different conformations in the crystallographic asymmetric unit. The X-ray analysis of the photoirradiated crystal showed that the photocyclization reaction of the molecule with the shorter distance between the reactive carbons prevails over the reaction of the other molecule. The mechanism has been discussed based on the calculation of the electronic transitions of the two molecules in the different conformations. The photocyclization quantum yield was determined to be 1 (100%) in the crystal.     

Über die Einkristalle von Polyparaxylylen

Zusammenfassung Aus verdünnter L?sung kristallisiert Polyparaxylylen in zweierlei Form, als rechteckige und als hexagonale Einkristalle, die sich in ihren Elektronenbeugungs- und in ihren R?ntgenbildern voneinander unterscheiden. Durch die r?ntgenographischen Messungen wurde festgestellt, da? diese zweierlei Einkristalle dem α- und dem β-Kristall entsprechen, die bereits beim massiven Material beobachtet werden. Die Kristallisations-bedingungen, die die morphologischen Strukturen der hergestellten Einkristalle sehr stark beeinflussen, wurden untersucht. Tempereffekte sowie dabei stattfindende Umwandlung von α- zu β-Form durch R?ntgen- und DTA-Messungen verfolgt.

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Summary Poly-p-xylylene crystallizes from some solvents into two single crystal forms, rectangular and hexagonal. These two single crystals show different X-ray and electron diffraction patterns, respectively. By X-ray measurements it was found that these two single crystals correspond to α- und β-crystal forms, which were observed with bulk materials by Brown and Farthing. It was also found that these morphological forms depend on the crystallization-conditions, especially on crystallization-solvents. The annealing effects and the transformation from α- to β-form were studied by X-ray diffraction and differential thermal analysis.

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Vorgetragen auf dem International Symposium on Makromolecular Chemistry, Kyoto, 3. Okt. 1966.

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Herrn Professor Dr. E. W. Fischer danken die Autoren für viele f?rdernde Diskussionen.     

A new one-electron model for extended Hückel type molecular orbital calculations

A new form of Coulomb and resonance integrals for extended Hückel type molecular orbital calculations was derived. In this model an electron moving in a molecule, when it stays in the neighborhood of the center of an atom in the molecule, sees the potential of the corresponding isolated atom. Compared with the well-known forms of Coulomb and resonance integrals, each integral derived from this model considers the influences from all atoms in the molecule, and includes the concept of atomic cell. The similarities of this model to other extended Hückel type formulations are also examined.     

Synthesis of(7e,9e,11e,13e)-18,18,18-trifluororetinal (all-trans 5-trifluoromethylretinal)

All-trans-18,18,18-trifluororetinal (2) was synthesized through trifluorocyclocitral (3) as a key intermediate.     

Alleviation of the chlorpromazine-induced muscular tissue damage by β-cyclodextrin complexation

From the gross and histological examinations, -cyclodextrin (-CyD) was found to reduce the muscular tissue damage produced by chlorpromazine hydrochloride (CPZ) onM. vastus lateralis in rabbits. The protective effect of -CyD may be attributable to the decrease in affinity of CPZ to the tissue membrane through inclusion complexation. There was no appreciable difference in the pharmacokinetic and pharmacodynamic behaviors between CPZ and its -CyD complex in rabbits. These results suggest that -CyD is useful to reduce the local tissue toxicity of CPZ without altering the pharmacological efficacy.     

Photochromism of dinaphthylethene derivatives. Stability of the closed-ring forms

Stability of various types of closed-ring forms of dinaphthylperfluorocyclopentenes was investigated from both experimental as well as theoretical points of view. The stability was dependent on the energy differences between the open-ring and the closed-ring forms. When the energy difference was small, the closed-ring form became stabler.