Multipotent stem cells are responsible for stomach epithelial homeostasis and production of four main cell lineages secreting mucins, acid, pepsinogen and hormones. Established mouse gastric stem (mGS) cell line isuseful tool to study the role adult stem cells in regenerative medicine and tissue engineering. We have recently shown that 3D microfibrous polycaprolactone scaffolds support growth and differentiation of mGS cells into stomach mucous cells after 9-day culture. One of the future applications of this 3D culture model is in the field of regenerative medicine of gastric mucosal defects. Since luminal pH of the stomach may have deleterious effect on the transplanted tissue. The current study examines the effects of acidic pH on mGS cells using 2D and 3D culture systems.
The S. cerevisiae IRC20 protein (Increased Recombination Centers 20) shares homology with an extended family of Snf2-related ATPases. It has previously been reported to play a role in homologous recombination repair and thus crucial in maintaining genome integrity following a double strand break. Mutations in SHPRH, the human homolog of IRC20, has been shown to be involved in several cancers. The exact mechanism of function of IRC20 in DNA repair is yet to be revealed. Here we report the purification of IRC20 using a TAP technique under native expression conditions, and using a His-tag on a plasmid for overexpression in yeast. Biochemical characterization of this complex reveals that it exhibits ATP-dependent chromatin remodeling activity. Consistent with this, it also binds to both DNA and chromatin.
Major depression (MD) and anxiety disorders (AD) are the most prevalent psychiatric disorders in the community (Rouillon 1999). Major depressive disorder (MDD) is a common psychiatric disorder with considerable morbidity and mortality (Harris and Barraclough 1998; Judd et al. 2008). A long-standing theory is that a breakdown in brain serotonin (5-hydroxytryptamine; 5-HT) signalling is critically involved in the symptoms and drug treatment of clinical depression (Sharp et al. 2011). The human serotonin transporter protein (SERT) is encoded by a single gene [SLC6A4]. A deletion/insertion in the 5-HTTLPR creates a short (S) or long (L) allele (14- or 16-repeat alleles), which alters the promoter activity. The S-variant has been reported to be associated with lower basal and transcriptional efficiency of the SLC6A4, resulting in lower serotonin uptake activity when compared with the L-variant (Nakamura et al, 2000, Zalsman et al, 2006). Dysfunction of 5-HT has been implicated in the aetiology of psychiatric disorders such as depression and anxiety (Neumeister et al, 2004, Sen et al, 2004).
In this work we deal with the pricing problem for European options under CEV models. We suggest a modified CEV model that covers post-crash markets. Using Monte Carlo methods we investigate numerical solutions for the pricing problem for European opt
The aim of this work is to study, via mathematical model, the impact of imported malaria on the population of United Arab Emirates (UAE). The nature of the health policies in UAE impose on us to consider a model that categorizes the living population in land of UAE to two categorizes. The local population, which represent the permanents resident that have not health requirement for their residency, and the non-locals, which are required to have certain health condition to maintain their status in the country. This paper includes the calculation of the basic reproduction number for the entire population R_0 and also for the sub-populations R^L_0 and R^N_0. Local and global stability of the disease free equilibrium of the model also were studied. Our goal is show the possible outcomes of such epidemic on both population and the control strategy to maintain lower epidemic size in UAE.
In this paper we consider multi-term fractional differential equations of Caputo's and Riemann-Liouville types. We propose a new series solution which is a modified form of the well known Taylor series expansion and differential transform methods. The main advantage of the new series solution comparing with the existing ones in the literature is, to overcome the difficulty of computing iterated fractional derivatives, which don't compute in general. The idea of the new approach was introduced recently by Al-Refai et al. [1] for a class of fractional differential equations of Caputo's type. Analysis of the new approach will be presented as well as, a comparison with the well known methods such as the Adomian decomposition and differential transform methods.
Many dynamical systems exhibit properties that are preserved by the flow, e.g., energy conservation, symmetry, momentum and symplecticity. A conventional numerical integrator approximates the flow of the continuous-time equations using only the information about the vector field, ignoring the physical laws and the properties of the original trajectory. In this way, small inaccuracies accumulated over long periods of time will significantly diminish the operational lifespan of such discrete solutions. Geometric integrators, on the other hand, are built in a way that preserve the structure of continuous dynamics, so maintaining the qualitative behaviour of the exact flow even for long-time integration. The aim of this paper is to design efficient geometric integrators for Hamiltonian systems. These methods are implicit for general Hamiltonian systems. We show that explicit integrators can be developed to solve some selected examples drawn from celestial mechanics.
We study the problem of maximizing the entropy rate of a Markov chain. This problem is motivated by two applications: constrained codes and strategy in adversarial settings. Given a directed graph, we would like to pick the edge transition probabilities to maximize the error probability of guessing the next state given knowledge of the current state. A simple combinatorial approach to this problem is provided.
Diabetes is characterized by high glucose levels in the blood that result from defects in insulin secretion, or its action, or both, being considered as one of the major contributors of precipitate infirmity and death in non-contagious diseases. Glucose meter is the prevailing technique to determine the glucose level, a technique involving chemical analysis of a sample of the diabetic blood obtained by pricking a finger. Yet, due to the many demerits of the glucose meter, including the pain and the direct contact requirement, many alternatives were proposed in the literature. In this paper, we explore and compare, based on a number of performance metrics, some of those techniques and systems and their compatibility to be implemented for Systemon- Chip (SoC) for glucose and health monitoring, which will potentially transform the future of healthcare. A preliminary SoC design for non-invasive glucose monitoring is proposed
This paper summarizes findings of the research investigating wireless power transfer to on-chip circuitry. The ultimate objective is to wirelessly power a non-invasive, biocompatible sensor-based microsystem that would detect the dislocation of orthodontic brackets. Three schemes that are based on inductive coupling are proposed in this paper and their respective power transfer efficiencies are investigated via Agilent Advanced Design System software. The first scheme studies the coupling behavior between an external coil to the orthodontic brace wire, whereas the second scheme examines brace wire to on-chip coupling. The third scheme looks into direct coupling between an external coil and an on-chip coil. The simulated coupling efficiencies are compared and the best coupling scheme is chosen with an efficiency of 3.87%.
