3D Hilbert resonator, although covering larger substrate area then other configurations, demonstrated very high values of unloaded Q. Simulations have shown that this advantage can further be exploited by decreasing line widths and spacing in the 3D curve, which can be easily done with LTCC technology. CONCLUSIONIn this paper, four novel multilayer microstrip resonators were analyzed via full-wave EM simulations and compared in terms of loaded and unloaded quality factor. All the dimensions were kept in accordance with standard TF procedure.The 3D Hilbert resonator was shown to be superior to all the other configurations examined, both 3D and 2D, thus demonstrating the benefits to be gained from the employment of multilayer fractal shapes in resonators and filters. [5]. In this paper, we propose a novel rectangular slot antenna embedded with a pair of narrow rectangular strips for dual-broadband operation in WLAN communication. Probably due to the narrow strip embedded symmetrically along the center line of the rectangularslot antenna, a new resonant mode close to the second resonant mode of the regular rectangular-slot antenna can be excited to enhance the operating bandwidth of high band, which simultaneously covers the required bandwidth of 5.2 GHz (5.15-5.35 GHz) and 5.8 GHz (5.725-5.825 GHz). It is found that by properly adjusting the spacing between the two narrow strips to be 2 mm, the obtained bandwidths for the 2.4-and 5-GHz bands are 11% (254 MHz) and 24.8% (1446 MHz), respectively, which is sufficient for wireless communication. The proposed dual-broadband rectangular slot antenna also provides the frequency ratio of two operating modes in the range of 1.66 -2.52 with various spacings between the two narrow strips, which is wider than that of the dual-broadband slot-antenna design [5]. The details of the proposed slot antenna designs are described, and the experimental results for the dual-broadband performance obtained are presented and discussed. ANTENNA DESIGNAs shown in Figure 1, a pair of narrow rectangular strips of width b and the length T is embedded symmetrically along the center line of the rectangular slot antenna. The spacing between the two rectangular strips is denoted as S here. The rectangular slot antenna of L ϫ W is etched on an inexpensive FR4 substrate with dielectric constant r (4.4) and substrate thickness h (0.8 mm). In this study, due to the presence of the embedded rectangular strips with less spacing, a new resonant mode close to the second resonant mode of the rectangular slot antenna can be easily excited in order to obtain the desired dual-broadband operation, for example, the WLAN operations in the 2.4-and 5.8-GHz bands. However, the fundamental resonant mode of the proposed slot antenna is less perturbed. And, as the spacing between two narrow strips is more than half of the length of the slot antenna, both of the two operating frequencies increase when the spacing is increased in order to obtain a different operating-frequency-variation trend, compared with the propo...

Two new butanolides, subamolide D (1) and subamolide E (2), and a new secobutanolide, secosubamolide A (3), along with 21 known compounds were isolated from the leaves of Cinnamomum subavenium. The structures of 1-3 were determined by spectroscopic analysis. Propidium iodide staining and cytometry analysis were used to evaluate the cell cycle progression of the treated SW480 cells and it was found that 1 and 2 caused DNA damage in a dose-and time-dependent manner.

The aim of this study was to evaluate the cytotoxic effects of three new butanolides, subamolides A - C (1-3), and a new secobutanolide, secosubamolide (4), on the human colorectal cancer cell line SW480. Compounds 1-4 are new and were isolated from the stems of Cinnamomum subavenium, along with 17 known compounds. The structures of 1-4 were determined by spectroscopic analysis. Propidium iodide staining and flow cytometry were used to evaluate DNA damage of the treated SW480 cells, and it was found that 1-4 caused DNA damage in a dose-dependent manner after 24 h of treatment.