Browsing by Author "Wang, Chun-Lin"

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A Particle-Swarm-Driven Cross-Entropy Method for MIMO Signal Detection
(2010)
Wang, Chun-Lin
;
Lin, Yu-Ting
;
Su, Yu T.
;
傳播研究所
;
Institute of Communication Studies
In this paper, we apply simulation-based optimization methods to detect quadrature amplitude modulated (QAM) MIMO signals. The first one is the so-called Cross-Entropy (CE) method which enables the corresponding CE-based detector to provide bit-error-rate (BER) performance close to that achievable by the maximum-likelihood (ML) detector when the signal-to-noise ratio (SNR) is relatively low. Unfortunately, the performance curves exhibit error floors in the high SNR region. To improve the performance in the high SNR region, we borrow the concept of Particle Swarm Optimization (PSO) and refer to the resulting iterative detector as the Particle-Swarm-driven Cross-Entropy (PSD-CE) MIMO detector. This detector gives a significant BER performance improvement in the medium-to-high SNR region. We also consider the case when the channel state information is imperfect and suggest a robust detector structure based on a modified score function.
Characterization of MRT, a new non-LTR retrotransposon in Monascus spp
(2007-10-01)
Chen, Yi-Pei
;
Tseng, Ching-Ping
;
Liaw, Li-Ling
;
Wang, Chun-Lin
;
Yuan, Gwo-Fang
A new non-LTR retrotransposon, named MRT, was discovered in the filamentous fungus Monascus pilosus BCRC38072. The entire nucleotide sequence of the MRT element was 5.5-kb long, including two open reading frames. These two ORFs showed homologies to gag-like and pol-like gene products, and an A-rich sequence at the 3' end of pol-like gene. ORF1 encoded a protein of 5 17 amino acids and contained a cysteine-rich zinc finger motif ORF2 encoded a protein of 1181 amino acids and contained apurinic/apyrimidinic endonuclease (APE), reverse transcriptase (RT), RNaseH domains, and a CCHC motif. The phylogenetic analyses demonstrated that the MRT element should be classified into the Tad1 clade. The results of Southern hybridizations showed that MRT elements were distributed within M pilosus, M ruber, M sanguineus, and M barkeri. In addition, the species of Monascus can be grouped by the presence or absence of MRT elements in the hybridization pattern according to phylogenctic subgroups established with the partial beta-tubulin gene.
Cloning and characterization of monacolin K biosynthetic gene cluster from Monascus pilosus
(2008-07-23)
Chen, Yi-Pei
;
Tseng, Ching-Ping
;
Liaw, Li-Ling
;
Wang, Chun-Lin
;
Chen, I-Ching
Monacolin K is a secondary metabolite synthesized by polyketide synthases (PKS) from Monascus, and it has the same structure as lovastatin, which is mainly produced by Aspergillus terreus. In the present study, a bacterial artificial chromosome (BAC) clone, mps01, was screened from the BAC library constructed from Monascus pilosus BCRC38072 genomic DNA. The putative monacolin K biosynthetic gene cluster was found within a 42 kb region in the mps01 clone. The deduced amino acid sequences encoded by the nine genes designated as mokA-mokl, which share over 54% similarity with the lovastatin biosynthetic gene cluster in A. terreus, were assumed to be involved in monacolin K biosynthesis. A gene disruption construct designed to replace the central part of mokA, a polyketide synthase gene, in wild-type M. pilosus BCRC38072 with a hygromycin B resistance gene through homologous recombination, resulted in a mokA-disrupted strain. The disruptant did not produce monacolin K, indicating that mokA encoded the PKS responsible for monacolin K biosynthesis in M. pilosus BCRC38072.
Gut microbiome changes in overweight male adults following bowel preparation
(2018-12-31)
Chen, Hui-Mei
;
Chen, Chung-Chu
;
Chen, Chien-Chi
;
Wang, Shen-Chih
;
Wang, Chun-Lin
BackgroundHuman gut microbiome has an essential role in human health and disease. Although the major dominant microbiota within individuals have been reported, the change of gut microbiome caused by external factors, such as antibiotic use and bowel cleansing, remains unclear. We conducted this study to investigate the change of gut microbiome in overweight male adults after bowel preparation, where none of the participants had been diagnosed with any systemic diseases.MethodsA total of 20 overweight, male Taiwanese adults were recruited, and all participants were omnivorous. The participants provided fecal samples and blood samples at three time points: prior to bowel preparation, 7days after colonoscopy, and 28days after colonoscopy. The microbiota composition in fecal samples was analyzed using 16S ribosome RNA gene amplicon sequencing.ResultsOur results demonstrated that the relative abundance of the most dominant bacteria hardly changed from prior to bowel preparation to 28days after colonoscopy. Using the ratio of Prevotella to the sum of Prevotella and Bacteroides in the fecal samples at baseline, the participants were separated into two groups. The fecal samples of the Type 1 group was Bacteroides-dominant, and that of the Type 2 group was Prevotella-dominant with a noticeable presence Bacteroides. Bulleidia appears more in the Type 1 fecal samples, while Akkermensia appears more in the Type 2 fecal samples. Of each type, the gut microbial diversity differed slightly among the three collection times. Additionally, the Type 2 fecal microbiota was temporarily susceptible to bowel cleansing. Predictive functional analysis of microbial community reveals that their activities for the mineral absorption metabolism and arachidonic acid metabolism differed significantly between the two types. Depending on their fecal type, the variance of triglycerides and C-reactive protein also differed between the two types of participants.ConclusionsDepending upon the fecal type, the microbial diversity and the predictive functional modules of microbial community differed significantly after bowel preparation. In addition, blood biochemical markers presented somewhat associated with fecal type. Therefore, our results might provide some insights as to how knowledge of the microbial community could be used to promote health through personalized clinical treatment.