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Phytochemical investigation on the 90% EtOH extract of the air-dried aerial parts of Hypericum ascyron resulted in the isolation of three new polycyclic polyprenylated derivatives ascyronines A-C (1-3). Structural elucidation of all the compounds was performed by spectral methods such as 1D and 2D (1H-1H COSY, HMQC, and HMBC) NMR spectroscopy. All the polycyclic polyprenylated acylphloroglucinols were evaluated for their antidepressant activity by inhibiting the reuptake of tritiated serotonin ([3H]-5-HT) and noradrenalinet ([3H]-NE) in rat brain synaptosomes. Compounds 2 and 3 exhibited weak antidepressant activities in the [3H]-5-HT mode. [ABSTRACT FROM AUTHOR]

Three previously undescribed ent-abietane-type diterpenoids, designated as 11β-hydroxy-14-oxo-17-al-ent-abieta-8(9),13(15)-dien-16,12β-olide (1), 11β,17-dihydroxy-12-methoxy-ent-abieta-8(14),13(15)-dien-16,12ɑ-olide (2), and 14ɑ-hydroxy-17-al-ent-abieta-7(8),11(12),13(15)-trien-16,12-olide (3), were isolated from 95% ethanol extract of the roots of Euphorbia wallichii. The structures of the new compounds were elucidated by spectroscopic analysis (NMR, IR, UV, and MS). The isolated diterpenoids were tested in vitro for antimicrobial potentials against 6 pathogenic microorganisms. As a result, compounds 1-3 exhibited some antimicrobial activity against the tested Gram positive bacteria with minimum inhibitory concentration values less than 60 μg/ml. [ABSTRACT FROM AUTHOR]

The fumigation bioassays, the oviposition inhibition and repellent bioassays of patchouli and wormwood oils to T. cinnabarinus were determined in the laboratory with the methods of fumigation and repellency. Ethovision XT6 was used to analyze the effects of two essential oils at sublethal dosages on the behaviors of T. cinnabarinus. Based on the results, compared with wormwood oil, the fumigation bioassay of patchouli oil was stronger against T. cinnabarinus. In a simultaneous fumigation experiment, the effects of patchouli oil on the inhibition of oviposition of T. cinnabarinus were significantly higher (P < 0.01) than those of wormwood oil at the tested dosages. When T. cinnabarinus was exposed to the two essential oils at LD10, LD20, and LD30, the spontaneous movement tracks of T. cinnabarinus changed significantly, with the highest mobility frequencies at LD10. Moreover, the effects of exposure to patchouli oil on the spontaneous movement abilities of T. cinnabarinus were greater than those on movements following exposure to wormwood oil. Thus, patchouli oil is a promising candidate as a green vegetable, botanical acaricide. [ABSTRACT FROM AUTHOR]

Cruise industry presents an active and rapid development in recent years. Due to the rich tourism resource and potential tourism market, China has become the core component of the Asian market. Identifying factors that affect cruise homeport selection systematically and designing scientific evaluation system are the keys to selecting the optimal cruise homeport location. We analysed the influence factors motivating the cruise liner companies to select a specific port as the cruise homeport and designed an index system includes both quantitative indices and qualitative indices following the basic principles of index selection. In order to resolve the problem of incomplete information and randomness of the decision-making process, the grey-cloud clustering model was used for evaluation of cruise homeport selection. Further, we conducted a case study to evaluate whether or not these nine cruise ports, such as Shanghai, Tianjin, Shenzhen and Sanya, are eligible to be homeports in China. Finally, several suggestions to improve the chance of being selected as a cruise homeport were recommended from viewpoints of port facilities, services and policy conditions. The results show that the model can reasonably and effectively help decision-makers to facilitate the homeport selection in real operations. [ABSTRACT FROM PUBLISHER]

The invalidity of the classical dipole theory as an emission mechanism for dispenser cathodes is discussed. A model of dynamic surface emission centres, proposed for explaining the observed phenomena in oxide cathodes, is extended to describe the thermionic emission from dispenser cathodes. The essential points of this model are: (1) on the solid surface, when a high-energy electron meets the tow potential field, this electron has a chance of being emitted into the vacuum; (2) the metal-like barium atoms provide high-energy electrons while oxygen, in the form of doubly charged negative ions, may provide a low potential field; (3) on the actual cathode surface, different conditions of adsorption form local emission centres; and (4) at high temperatures, these centres are not stagnant but everchanging, so that the cathodc operates in a state of dynamic equilibrium. Recent data from various electron spectroscopies on prepared films as wctl as dispenser cathodes seem to support this new model. [ABSTRACT FROM AUTHOR]

Examines thermionic emission instabilities in oxide cathodes. Dynamic surface emission centers in the coating and base metal; Number of emitted and injected electrons; Bombardment of grains by conducting electrons; Dissociation of the oxide; Secondary electron emission.

Discusses the emission mechanism of oxide cathodes through bulk donor concentration, electrical conductivity, activation, compositions and uniformity of emission. Role of oxygen in oxide cathode emission; Adsorption of barium from the base metal to the emission site; Similarities between nucleated islands and surface emission centers of the cathode.