Wireless Fractal Cellular Networks

With the seamless coverage of wireless cellular networks in modern society, it is interesting to consider the shape of wireless cellular coverage. Is the shape a regular hexagon, an irregular polygon, or another complex geometrical shape? Based on fractal theory, the statistical characteristic of the wireless cellular coverage boundary is determined by the measured wireless cellular data collected from Shanghai, China. The measured results indicate that the wireless cellular coverage boundary presents an extremely irregular geometrical shape, which is also called a statistical fractal shape. Moreover, the statistical fractal characteristics of the wireless cellular coverage boundary have been validated by values of the Hurst parameter estimated in angular scales. The statistical fractal characteristics of the wireless cellular coverage boundary can be used to evaluate and design the handoff scheme of mobile user terminals in wireless cellular networks.Comment: 16 pages, 4 figure

Genetic Diversity and Population Structure of Acanthochiton rubrolineatus (Polyplacophora) Based on Mitochondrial and Nuclear Gene Markers

Acanthochiton rubrolineatus (Cryptoplacidae, Neoloricata, Polyplacophora) has a narrow distribution range along the seacoasts of China, the Korean Peninsula and Japan. We collected 238 samples from eight localities along the Chinese coast, and analyzed the genetic diversity and population structure with COI, 16S-rRNA and 28S-rRNA gene sequences. All analyses based on combined sequences of COI and 16S-rRNA suggested that there was evident genetic differentiation between the northern populations (YT, WH, DL, QD, LYG) and southern populations (ZS, YH, XM) of A. rubrolineatus. The haplotype distribution pattern and genetic diversity based on 28S-rRNA sequences also supported the genetic divergence between the two groups. Both groups had experienced population expansion after the ice age of Pleistocene, and an additional population bottleneck had happened in the southern group in recent history, which led to low genetic diversity of mitochondrial DNA and abnormally high diversity of nuclear DNA in this group. Our results suggested that the protection on A. rubrolineatus is necessary, and the northern and southern group should be protected separately

Data from: Phylogeography of Chinese house mice (Mus musculus musculus/castaneus): distribution, routes of colonization and geographic regions of hybridization

Here, we present a comprehensive analysis of the biogeographic history of Chinese house mice based on data from mtDNA control region sequences and 10 microsatellite loci in 535 individuals sampled from 29 localities. Phylogenetic analyses revealed two distinct evolutionary lineages corresponding to M. m. castaneus in the South and M. m. musculus in the North, with the Yangtze River roughly representing the boundary between these subspecies. More detailed analyses using published sequence data from mice sampled in neighboring countries revealed the migration routes of the two subspecies into China: M. m. castaneus appears to have migrated through a southern route (Yunnan and Guangxi), while M. m. musculus entered China from Kazakhstan through the northwest border (Xinjiang). Bayesian analyses of mitochondrial sequences indicated rapid population expansions in both subspecies, approximately 4,650-9,300 years ago for M. m. castaneus and approximately 7,150-14,300 years ago for M. m. musculus. Interestingly, the migration routes of Chinese house mice coincide with the colonization routes of modern humans into China, and the expansion times of house mice are consistent with the development of agriculture in southern China and northern China respectively. Finally, our study confirmed the existence of a hybrid zone between M. m. castaneus and M. m. musculus near the Yangtze River. Further study of this hybrid zone will provide a useful counterpart to the well-studied hybrid zone between M. m. musculus and M. m. domesticus in central Europe

Combined Chemical Groups and Topographical Nanopattern on the Poly(ε-Caprolactone) Surface for Regulating Human Foreskin Fibroblasts Behavior

Surface chemistry and substrate topography could contribute significantly to providing a biochemical and topographical cues for governing the fate of cells on the cell–material interface. However, the synergies between these two properties have not been exploited extensively for biomaterial design. Herein, we achieved spatial-controlled patterning of chemical groups on the poly­(ε-caprolactone) (PCL) surface by elegant UV-nanoimprint lithography (UN-NIL). The introduction of chemical groups on the PCL surface was developed by our newly 6-benzyloxycarbonylmethyl-ε-caprolactone (BCL) monomer, which not only solved the lack of functional groups along the PCL chain but also retained the original favorable properties of PCL materials. The synergetic effect of the chemical groups and nanopatterns on the human foreskin fibroblasts (HFFs) behaviors was evaluated in detail. The results revealed that the patterned functional PCL surfaces could induce enhanced cell adhesion and proliferation, further trigger changes in HFFs morphology, orientation and collagen secretion. Taken together, this study provided a method for straightforward fabrication of reactive PCL surfaces with topographic patterns by one-step process, and they would facilitate PCL as potential candidate for cell cultivation and tissue engineering

Genetic diversity and population structure of penis fish (<i>Urechis unicinctus</i>) based on mitochondrial and nuclear gene markers

<p><i>Urechis unicinctus</i> is distributed only in Bohai Gulf of China and Korean and Japanese coast. The wild populations of this species have sharply declined in China and Japan. We collected 105 samples from six localities of Bohai Gulf and Korea coast, and investigated genetic diversity and population structure with mitochondrial <i>COI</i>, 16S-rRNA and nuclear 28S-rRNA gene fragments. Genetic diversity of <i>U. unicinctus</i> based on <i>COI</i> sequences was still high (Hd: 0.9595, π: 0.0101), however, 28S-rRNA gene sequences showed low level of genetic diversity (Hd: 0.4084, π: 0.0007). Based on <i>COI</i> sequences, <i>F</i>_ST values between populations ranged from −0.00204 to 0.05210, and 99.12% genetic diversity was contributed by different individuals within population. Both phylogenetic trees and median-joining network did not show clear geographic cluster, haplotypes from different populations were mixed. Our results indicated low level of genetic divergence among different localities of <i>U. unicinctus</i>, and this species should be treated as a whole population among China, Japan and Korea coast during species conservation.</p

Induction of KLF4 in response to heat stress

Krüppel-like factor 4 (KLF4) is an evolutionarily conserved zinc finger–containing transcription factor with diverse regulatory functions in cell growth, proliferation, differentiation, and embryogenesis. However, little is known about the response of KLF4 to heat stress. In this study, Western blot and reverse transcriptase–polymerase chain reaction were performed to determine the changes in KLF4 expression in response to heat stress. The results showed that heat stress up-regulated KLF4 messenger RNA and protein levels in a time-dependent manner in vivo and in 4 cell lines. Moreover, a study with heat shock transcription factor 1 (Hsf1) gene knockout mice indicated that the induction of KLF4 in response to heat stress was mediated by Hsf1. This process occurred rapidly, indicating that KLF4 is an immediate early response gene of heat stress. Next, the roles of KLF4 under heat stress conditions were analyzed for cells overexpressing or deficient in KLF4. The results showed overexpression of KLF4 increased the death rate of C(2)C(12) cells, whereas KLF4 deficiency decreased the injury of C(2)C(12) cells from heat stress conditions, suggesting that KLF4 might play an important role in cell injury induced by heat stress. KLF4 might be an immediate early response gene and could play an important role in cell injury induced by heat stress