Oscillation of solutions of some higher order linear differential equations

In this paper, we deal with the order of growth and the hyper order of solutions of higher order linear differential equations $$f^{(k)}+B_{k-1}f^{(k-1)}+\cdots+B_1f'+B_0f=F$$ where $B_j(z) (j=0,1,\ldots,k-1)$ and $F$ are entire functions or polynomials. Some results are obtained which improve and extend previous results given by Z.-X. Chen, J. Wang, T.-B. Cao and C.-H. Li

Bounds for the sums of zeros of solutions of u(m)=P(z)uu^{(m)}=P(z)u where PP is a polynomial

The main purpose of this paper is to consider the differential equation $u^{(m)}=P(z)u$ $(m\geq 2)$ where $P$ is a polynomial with in general complex coefficients. Let $z_{k}(u),$ $k=1,2,\ldots$ be the zeros of a nonzero solution $u$ to that equation. We obtain bounds for the sums $$\sum_{k=1}^{j}\frac{1}{|z_{k}(u)|}\quad (j\in\mathbb{N})$$ which extend some recent results proved by Gil'

Uniqueness and value distribution for q-shifts of meromorphic functions

In this paper, we deal with value distribution for q-shift polynomials of transcendental meromorphic functions with zero order and obtain some results which improve the previous theorems given by Liu and Qi [18]. In addition, we investigate value sharing for q-shift polynomials of transcendental entire functions with zero order and obtain some results which extend the recent theorem given by Liu, Liu and Cao [17]

Benzoxime inhibits matrix metalloproteinase-13 activation and cartilage damage in osteoarthritis rats via inhibition of NF-κB pathway

Purpose: To investigate the effect of benzoxime on degradation of  articular cartilage in a rat model of osteoarthritis (OA), and the mechanism involved.Methods: The OA rat model was prepared by injecting monosodium  iodoacetate (MIA) intra-articularly to Wistar rats. Rats in the treatment group were given benzoxime (5 mg/kg) daily for 21 days through the intra-articular route. The animals were then examined for behavioral changes by assessment of asymmetry in bearing weight and paw  withdrawal threshold of the hind limb. Western blot assay was used for the analysis of inflammatory cytokine expressions.Results: The expression of P2X purinoceptor 7 receptor (P2X7R) mRNA was significantly elevated in the OA rats (p < 0.02). However, benzoxime treatment caused a marked decrease in the level of P2X1-8R mRNA. Benzoxime treatment also prevented asymmetry in bearing weight, decreased paw withdrawal threshold, and inhibited the expressions of interleukin-1β, interleukin-6 and tumor necrosis factor-α in plasma and cartilage. Moreover, benzoxime exhibited significant inhibitory effects on the expressions of P2X7R, matrix metalloproteinase (MMP)-13 and prostaglandin E2 (PGE2) in cartilage tissue. It also significantly  suppressed OA-induced increases in the levels of inhibitor of nuclear factor-κB (NF-κB) kinase (IKK)α, IKKβ, IκBα and NF-κB p65, and blocked OA-induced increases in the expressions of P2X7R, MMP-13 and PGE2.Conclusion: These results demonstrate that benzoxime prevents cartilage degradation in OA rats by targeting NF-κB signaling pathway. Thus, benzoxime possesses clinical and therapeutic potentials for the prevention of cartilage degradation in OA.Keywords: Interleukin-1β, Purinoceptor-7, Benzoxime, Osteoarthritis, Prostaglandin, Matrix metalloproteinase

Antitumor Cyclic Hexapeptides from Rubia Plants: History, Chemistry, and Mechanism (2005–2011)

Rubiaceae-type cyclopeptides (RAs), cyclic hexapeptides from Rubia plants, have shown potential antitumor activity in vitro and in vivo. Based on the review about plant cyclopeptides (Chem. Rev., 2006, 106: 840), this mini-review will highlight new progress on the discovery, synthesis, and mechanism of RAs isolated during 2005 to 2011, covering recent work in our group

Heritable and Lineage-Specific Gene Knockdown in Zebrafish Embryo

BACKGROUND: Reduced expression of developmentally important genes and tumor suppressors due to haploinsufficiency or epigenetic suppression has been shown to contribute to the pathogenesis of various malignancies. However, methodology that allows spatio-temporally knockdown of gene expression in various model organisms such as zebrafish has not been well established, which largely limits the potential of zebrafish as a vertebrate model of human malignant disorders. PRINCIPAL FINDING: Here, we report that multiple copies of small hairpin RNA (shRNA) are expressed from a single transcript that mimics the natural microRNA-30e precursor (mir-shRNA). The mir-shRNA, when microinjected into zebrafish embryos, induced an efficient knockdown of two developmentally essential genes chordin and alpha-catenin in a dose-controllable fashion. Furthermore, we designed a novel cassette vector to simultaneously express an intronic mir-shRNA and a chimeric red fluorescent protein driven by lineage-specific promoter, which efficiently reduced the expression of a chromosomally integrated reporter gene and an endogenously expressed gata-1 gene in the developing erythroid progenitors and hemangioblasts, respectively. SIGNIFICANCE: This methodology provides an invaluable tool to knockdown developmental important genes in a tissue-specific manner or to establish animal models, in which the gene dosage is critically important in the pathogenesis of human disorders. The strategy should be also applicable to other model organisms

Surface ligand controls silver ion release of nanosilver and its antibacterial activity against Escherichia coli

Understanding the mechanism of nanosilver-dependent antibacterial activity against microorganisms helps optimize the design and usage of the related nanomaterials. In this study, we prepared four kinds of 10 nm-sized silver nanoparticles (AgNPs) with dictated surface chemistry by capping different ligands, including citrate, mercaptopropionic acid, mercaptohexanoic acid, and mercaptopropionic sulfonic acid. Their surface-dependent chemistry and antibacterial activities were investigated. Owing to the weak bond to surface Ag, short carbon chain, and low silver ion attraction, citrate-coated AgNPs caused the highest silver ion release and the strongest antibacterial activity against Escherichia coli, when compared to the other tested AgNPs. The study on the underlying antibacterial mechanisms indicated that cellular membrane uptake of Ag, NAD+/NADH ratio increase, and intracellular reactive oxygen species (ROS) generation were significantly induced in both AgNP and silver ion exposure groups. The released silver ions from AgNPs inside cells through a Trojan-horse-type mechanism were suggested to interact with respiratory chain proteins on the membrane, interrupt intracellular O2 reduction, and induce ROS production. The further oxidative damages of lipid peroxidation and membrane breakdown caused the lethal effect on E. coli. Altogether, this study demonstrated that AgNPs exerted antibacterial activity through the release of silver ions and the subsequent induction of intracellular ROS generation by interacting with the cell membrane. The findings are helpful in guiding the controllable synthesis through the regulation of surface coating for medical care purpose