• Earthquakes and Structures
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• v.15 no.6
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• pp.639-654
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• 2018

Rocking motion have been used for achieving the 'resilient buildings' against earthquakes in recent studies. Low-rise buildings, unlike the tall ones, because of their small aspect ratio tend to slide rather than move in rocking mode. However, since rocking is more effective in seismic response reduction than sliding, it is desired to create rocking motion in low-rise buildings too. One way for this purpose is making the building's structure rock on its internal bay(s) by reducing the number of bays at the lower part of the building's skeleton, giving it a mushroom form. In this study 'mushroom skeleton' has been used for creating multi-story rocking regular steel buildings with square plan to rock on its one-by-one bay central lowest story. To show if this idea is effective, a set of mushroom buildings have been considered, and their seismic responses have been compared with those of their conventional counterparts, designed based on a conventional code. Also, a set of similar buildings with skeleton stronger than code requirement, to have immediate occupancy (IO) performance level, have been considered for comparison. Seismic responses, obtained by nonlinear time history analyses, using scaled three-dimensional accelerograms of selected earthquakes, show that by using appropriate 'mushroom skeleton' the seismic performance of buildings is upgraded to mostly IO level, while all of the conventional buildings experience collapse prevention (CP) level or beyond. The strong-skeleton buildings mostly present IO performance level as well, however, their base shear and absolute acceleration responses are much higher than the mushroom buildings.

• Journal of Microbiology and Biotechnology
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• v.13 no.5
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• pp.778-782
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• 2003

In the course of screening anti-influenza agents from natural products, four neuraminidase inhibitors were isolated from the methanol extract of mushroom Microphorus affinis by purification using solvent partition, silica gel column chromatography, Sephadex LH-20, and semi-preparative HPLC. The chemical structures of these compounds were identified as ${\alpha}-lupeol$, methyl linoleate, methyl palmitate, and methyl oleate by means of spectral data including GC-MS, $^1H-,\;and\;^{13}C-NMR\;with\;IC_{50}$ values of 5.65, 7.07, 7.12, and $7.52\;\mu\textrm{M}$, respectively. They did not inhibit other glycosidases such as glucosidase, mannosidase, and galactosidase, indicating that they were relatively specific inhibitors of neuraminidase. The relationship between the fatty acid structure and inhibitory activity was investigated. The result showed that, in the case of an aliphatic linear hydrocarbon skeleton, at least one carboxyl (presumably any carbonyl) moiety and sixteen carbons were the necessary requirements for potent inhibition, whereas saturated, unsaturated, free, and ester forms did not have any significant effect on the activity.