A geometric-process maintenance model for a deteriorating system under a random environment

This paper studies a geometric-process maintenance-model for a deteriorating system under a random environment. Assume that the number of random shocks, up to time t, produced by the random environment forms a counting process. Whenever a random shock arrives, the system operating time is reduced. The successive reductions in the system operating time are statistically independent and identically distributed random variables. Assume that the consecutive repair times of the system after failures, form an increasing geometric process; under the condition that the system suffers no random shock, the successive operating times of the system after repairs constitute a decreasing geometric process. A replacement policy N, by which the system is replaced at the time of the failure N, is adopted. An explicit expression for the average cost rate (long-run average cost per unit time) is derived. Then, an optimal replacement policy is determined analytically. As a particular case, a compound Poisson process model is also studied.published_or_final_versio

Polymorphism and association of microsatellite SJ01 with birth weight and early growth traits in pigs

Myostatin is a negative regulator of animal skeletal muscle development and SJ01 is a microsatellite locus flanking porcine myostatin gene. In the present study, the polymorphism of microsatellite SJ01 in three pig populations, that is, Duroc (n = 420), Yorkshire (n = 414) and Landrace (n = 119), were investigated, and its associations with birth weight and early growth traits were analyzed. The results indicated that genotype BB was predominant in Yorkshire pigs and allele B was predominant in both Yorkshire and Landrace pigs, whereas allele A was more prevalent in Duroc pigs. Among the three pig breeds, Duroc population had the highest heterozygosity and deviated from Hardy-Weinberg equilibrium (P < 0.05). The average daily gain from 28 d to 70 d in Yorkshire pigs and the body weight at 70 d in Landrace pigs were significantly different between SJ01 genotypes (P < 0.05). These resultssuggest that microsatellite SJ01 is a potential DNA marker for early growth trait selection in Yorkshire and Landrace pigs as well as for refining QTL for early growth traits on SSC15

SERS-Enabled Lab-on-a-Chip Systems

Surface-enhanced Raman spectroscopy (SERS) has been combined with microfluidic Lab-on-a-Chip (LoC) systems for sensitive optofluidic detection for more than a decade. However, most microfluidic SERS devices still suffer from analyte contamination and signal irreproducibility. In recent years, both the microfluidics and SERS communities have developed their own solutions that are complementary to each other; their combination even has potential for commercialization. In this review, the recent advances in both fields are summarized with regard to the development of reliable multifunctional SERS-enabled LoC systems and their broad applications. Starting from SERS fundamentals, reproducible SERS substrates and dynamic microfluidic trapping are discussed. Based on their combination, on-chip applications beyond SERS are presented, and insight can be gained into the commercialization of portable SERS chips.postprin

The behavior of two-way reinfoced concrete slabs externally strengthened with steel plate to subject patch load

2001-2002 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Human induced pluripotent stem cell-derived mesenchymal stem cells are superior to adult bone marrow-derived mesenchymal stem cells in the treatment of limb ischemia

Conference invited speaker: Dr. Lian, QOral Presentation: Session S31 - Genetic Determinants of Heart Disease, Gene and Cell Based Therapies, Basic Research: abstract no. 1489postprintThe 16th World Congress on Heart Disease of the International Academy of Cardiology Annual Scientific Sessions 2011, Vancouver, B.C., 23-27 July 2011

Isolation and Purification of Sesquiterpene Lactones from Ixeris sonchifolia (Bunge) Hance by High-Speed Counter- Current Chromatography and Semi-Preparative High Performance Liquid Chromatography

Purpose: To isolate and purify sesquiterpene lactones from Ixeris sonchifolia (Bunge) Hance by highspeed counter-current chromatography (HSCCC).Methods: I. sonchifolia was extracted with water and then loaded on a glass column (10 ~ 1500 cm containing 3000g D101 macroporous resin) where various concentrations of aqueous ethanol (0, 10, 30, 50, and 95 %) were used to elute the column successively. The 50 % ethanol fraction was  purified by HSCCC using a solvent system comprised of ethyl acetate: n-butanol: methanol: water (4: 6: 1: 20, v/v), and semi-preparative high performance liquid chromatography (HPLC). The chemical structures of thecomponents obtained were further confirmed by high-resolution mass spectroscopy (MS) and nuclear magnetic resonance spectroscopy (NMR).Results: Three compounds, including ixerin Z1 (0.7 mg), ixerin Z (11.4 mg), and 11, 13α-dihydroixerin Z (8.2 mg), with purity of 96.2, 98.2, and 98.4 %, respectively, were obtained from 200 mg each of the 50 % ethanol fraction.Conclusion: HSCCC is a rapid and effective method for isolating and purifying sesquiterpene lactones from I. sonchifolia.Keywords: Sesquiterpene lactones, High-speed counter-current chromatography, Ixeris sonchifolia, Ixerin, 13α-Dihydroixeri

Effect of the Chinese herb Mesima Reishi UE-1 on invasion of human ovarian cancer cells in vitro

To study the effects of Mesima Reishi UE-1 on the metastatic phenotype of the human ovarian cancer cell line HO8910. HO8910 cells were pretreated with different concentration of Mesima Reishi UE-1 in vitro. Using cell proliferation assay, spreading and adhesion assay, cell migration and invasion assay, zymography, immunocytochemical staining and RT-PCR, we examined the effects of Mesima Reishi UE- 1 on cell proliferation, motility, adhesion and expression of MMP-2, 9 in vitro. Mesima Reishi UE-1 directly inhibited HO8910 cell proliferation in vitro. And pretreated with different concentrations of Mesima Reishi UE-1, HO8910 cells motility, adhesion and invasion were inhibited significantly. The activity of MMP-9 was inhibited in a dose-dependent manner. The protein and mRNA expression of MMP-2, 9 were also inhibited. Mesima Reishi UE-1 suppresses invasion of human ovarian cancer cells in vitro.Key words: Mesima Reishi UE-1, polysaccharides, human ovarian cancer, tumor invasion, matrix metalloproteinase

Ultra-low carrier concentration and surface dominant transport in Sb-doped Bi2Se3 topological insulator nanoribbons

A topological insulator is a new state of matter, possessing gapless spin-locking surface states across the bulk band gap which has created new opportunities from novel electronics to energy conversion. However, the large concentration of bulk residual carriers has been a major challenge for revealing the property of the topological surface state via electron transport measurement. Here we report surface state dominated transport in Sb-doped Bi2Se3 nanoribbons with very low bulk electron concentrations. In the nanoribbons with sub-10nm thickness protected by a ZnO layer, we demonstrate complete control of their top and bottom surfaces near the Dirac point, achieving the lowest carrier concentration of 2x10^11/cm2 reported in three-dimensional (3D) topological insulators. The Sb-doped Bi2Se3 nanostructures provide an attractive materials platform to study fundamental physics in topological insulators, as well as future applications.Comment: 5 pages, 4 figures, 1 tabl