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This work demonstrates the use of low-energy ultrasound (US) to enhance secondary metabolite production in plant cell cultures. Suspension culture of Lithospermum erythrorhizon cells was exposed to low-power US (power density < or = 113.9 mW/cm(3)) for short periods (1-8 min). The US exposure significantly stimulated the shikonin biosynthesis of the cells,(More)
Connected dominating set based routing is a promising approach for enhancing the routing efficiency in wireless ad hoc networks. However, finding the minimum dominating set in an arbitrary graph is a NP-hard problem. In this paper, we propose a simple and efficient distributed algorithm for constructing a connected dominating set in wireless ad hoc networks(More)
We propose an efficient centralized scheduling algorithm in IEEE 802.16 based Wireless Mesh Networks (WMN) to provide high qualified wireless multimedia services. Our algorithm takes special attention on the relay function of the mesh nodes in a transmission tree which is seldom studied in previous research. Some important design metrics, such as fairness,(More)
The stress metabolic activities of Panax ginseng (P. ginseng) cells induced by low-energy ultrasound (US) were examined. P. ginseng cells in suspension cultures were exposed to 38.5 kHz US at two power levels (power density 13.7 and 61 mW/cm(3)) for 2 min. The US treatment caused rapid increase in the intracellular levels of polyphenol oxidase (PPO),(More)
Three new sesquiterpenes including a rearranged hirsutane, dichomitol (1), an aromadendrane, 2beta,13-dihydroxyledol (2), and a 1,10-seco-2,3-seco-aromadendrane, dichomitone (3), were isolated from mycelial solid cultures of Dichomitus squalens. Their structures were elucidated by spectroscopic methods, and their nematicidal activities against(More)
Recently, IEEE has standardized the 802.16 protocol for wireless metropolitan area networks. In the point-to-multipoint (PMP) mode of the medium access control (MAC), the subscriber stations (SSs) request bandwidth based upon unicast, multicast and broadcast polling by the base station (BS). Polling is the process by which the BS allocates to the SSs(More)
Anycasting has recently become an important research topic, especially for replicated servers. With anycasting, applications can request the "nearest" server for provision of desired (multimedia) service. In this paper, we study efficient distributed admission control (DAC) for anycast flows. We focus on algorithms that perform destination selection and(More)
In IEEE 802.16 networks, initial ranging is a primary and important procedure of connection setup between subscriber stations and base station. The mandatory method defined in the standard of contention resolution is based on a truncated binary exponential backoff, with a fixed initial contention window size. However, the original algorithm neglects the(More)
This paper presents a novel analytical model and an efficient admission control (AC) algorithm for IEEE 802.11 distributed coordinated function access mechanism. In contrast to the previous approaches, both saturated and unsaturated states of network are analyzed and the impacts of error-frame rate and retransmission limit are also taken into account based(More)
Four new sesquiterpene dilactones, mikamicranolide (1), 11 beta,13-dihydromikamicranolide (2), 3 alpha-hydroxy-11 beta,13-dihydrodeoxymikanolide (3), and 2 beta,3 beta-dihydroxy-11 beta,13-dihydrodeoxymikanolide (4), were isolated from the whole plants of Mikania micrantha. Their structures were elucidated on the basis of spectroscopic analysis. Compounds 1(More)