Quasi-Rip: A New Type of Rip Model without Cosmic Doomsday

The fate of our universe is an unceasing topic of cosmology and the human being. The discovery of the current accelerated expansion of the universe significantly changed our view of the fate of the universe. Recently, some interesting scenarios concerning the fate of the universe attracted much attention in the community, namely the so-called "Little Rip" and "Pseudo-Rip". It is worth noting that all the Big Rip, Little Rip and Pseudo-Rip arise from the assumption that the dark energy density $\rho(a)$ is monotonically increasing. In the present work, we are interested to investigate what will happen if this assumption is broken, and then propose a so-called "Quasi-Rip" scenario, which is driven by a type of quintom dark energy. In this work, we consider an explicit model of Quasi-Rip in detail. We show that Quasi-Rip has an unique feature different from Big Rip, Little Rip and Pseudo-Rip. Our universe has a chance to be rebuilt from the ashes after the terrible rip. This might be the last hope in the "hopeless" rip.Comment: 9 pages, 2 figures, 1 table, revtex4; v2: discussions added, Phys. Rev. D in press; v3: published versio

Wound-healing effect of Platycodon grandiflorus (Jacq.) extract in rats

Purpose: To evaluate the healing effect of Platycodon grandiflorus (Jacq.). extract (PGE) on experimental burn wounds in rats. Methods: Rats were randomly divided into four groups of eight rats each: control group, silver sulfadiazine (SSD)-treated group, moist exposed burn ointment (MEBO)-treated group and PGE-treated group. PGE, SSD and MEBO were applied topically twice daily for 7 days. SSD and MEBO were used as reference control. External observation of wound area contraction and histological analysis of wound tissues was performed respectively. The effect of PGE on matrix metalloproteases (MMPs), vascular endothelial growth factor (VEGF) and Type-III Collagen proteins of wound tissue in rats were analysed by Western blot. Results: After 10 days of topical treatment with PGE, PGE-treated group showed faster reduction in wound area when compared with control groups (p < 0.01). Matrix metalloprotease-2 (MMP-2), matrix metalloprotease-9 (MMP-9), VEGF and type-III collagen expressions in the wound tissue increased significantly (p < 0.05) when compared with the control burn wounds. Histological results showed an overall early recovery and regeneration in PGE-treated group when compared with control group. Conclusion: PGE possesses a significant wound-healing activity in full-thickness burn wounds in rats. Therefore, it can potentially be developed for the management of burns

In-silico design of novel 4-aminoquinolinyl analogs as potential anti-malaria agents using quantitative structure– activity relationships and ADMET approach

Purpose: To design and screen for potential anti-malaria agents based on a series of 4-aminoquinolinyl analogues.Methods: Molecular fingerprint analysis was used for molecular partitioning of training and test sets. Acquired training sets were used for CoMFA and CoMSIA model construction after good alignment was achieved. Partial least squares analysis combined with external validation were used for  model evaluation. Deep analysis of acquired contour maps was performed to summarize the substituent property requirements for further rational molecular design. Using the chosen models, activity prediction and subsequent ADMET investigation were performed to discover novel designed  compounds with the desired properties.Results: Three different set partitions for model establishment were obtained using fingerprint-based selection. Partition 02 offered an optimal CoMFA model (r2 = 0.964, q2 = 0.605 and r2pred = 0.6362) and the best CoMSIA model (r2 = 0.955, q2 = 0.585 and r2 pred = 0.6403). Based on contour map analysis, a series of compounds were designed for activity prediction. Two of the compounds (wmx09, wmx25) were chosen for their ideal predicted biological activities. Subsequent ADMET investigation indicated that these compoundss have acceptable drug-like characteristics.Conclusion: The screening reveals that compounds wmx09 and wmx25 have strong potential as antimalaria agents. Keywords: Malaria, 4-Aminoquinolinyl, Molecular fingerprint, QSAR, ADME

A Preliminary Study of the Microbial Resources and Their Biological Activities of the East China Sea

East China Sea is one of the four sea areas in China, which possesses peculiar ecological environment and many kinds of living creatures, especially the microorganisms. We established the East China Sea microorganism library (during 2006–2010) for the first time, which stored about 30000 strains that covered most kinds of the species. In this paper, 395 pure strains of East China Sea microorganism library which belong to 33 different genera were mainly introduced. Sulfitobacter, Halomonas, Bacillus, Pseudoalteromonas, and Idiomarina were the most dominant species. On the large-scale biological activity screening of the 395 strains, 100 strains possess different biological activities based on different screening models, of which 11.4% strains have antibacterial activities, 15.9% have cytotoxicity activities, and 6.1% have antioxidation activities. Besides, the secondary metabolites of 6 strains with strong biological activities were studied systematically; diketopiperazines and macrocyclic lactones are the active secondary metabolites. The species and the biological activity of microorganisms diversity, the abundant structure type of the secondary metabolites, and their bioactivities all indicate that East China Sea is a potent marine microorganisms-derived developing resource for drug discovery

Structure characterization and antioxidant properties of proteins extracted from the larva of Bombyx mori L.

Purpose: To explore the structural characteristics and antioxidant properties of proteins extracted by salt extraction and ammonium sulfate precipitation (SEAP) from the larvae of Bombyx mori L. (PLB) that died due to infection with Beauveria bassiana (Bals.) Vuill.Methods: The extraction yield of PLB was measured, and protein patterns were examined by SDSPAGE. The amino acid composition of PLB was analyzed using an automatic amino acid analyzer while the structural characteristics of PLB were analyzed by Fourier transform infrared (FT-IR) and UV techniques. In addition, the antioxidant properties of PLB were investigated in vitro.Results: The extraction yield of PLB was 2.16 ± 0.04 %. PLB protein was mainly present in 10 – 20 and 25 – 35 kDa fractions. PLB consisted of 15 types of amino acids. Glu (12.45 ± 0.06), Ala (6.87 ± 0.11) and Val (4.55 ± 0.11) contents of PLB were significantly (p < 0.05) higher relative to that of other amino acids. PLB exhibited the FT-IR and UV spectra characteristics of proteins. In addition, PLB exhibited significant antioxidant effects (p < 0.05).Conclusion: The results indicate that PLB exhibits significant antioxidant effects and may be suitable for development into antioxidant drugs.Keywords: Bombyx mori L., Proteins, Structural characteristics, Antioxidant, Beauveria bassian