A QoS aware services mashup model for cloud computing applications

Purpose: With the popularity of cloud computing, cloud services have become to be application programming platform where users can create new applications mashup(composing) the functionality offered byothers.By composing of distributed, cloud services dynamicallyto provide more complex tasks, services mashup provides an attractive way for building large-scale Internet applications.One of the challenging issues of cloud services mashup is how to find service paths to route the service instances provider through whilemeeting the applications’ resource requirements so that the QoS constraints are satisfied. However, QoS aware service routing problem istypically NP-hard.The purpose of this paper is to propose a QoS Aware Services Mashup(QASM) model to solve this problem more effectively. Design/methodology/approach: In this paper, we focus on the QoS aware services selection problem in cloud services mashup, for example, given the user service composition requirements and their QoS constraint descriptions, how to select the required serviceinstances and route the data flows through these instances so that the QoS requirements are satisfied. We design a heuristic algorithm to find service paths to route the data flows through whilemeeting the applications’ resource requirements and specific QoS constraints. Findings: This study propose a QoS Aware Services Mashup(QASM) model to solve this problem more effectively. Simulations show that QASM can achieve desired QoS assurances as well as load balancing in cloud services environment. Originality/value: This paper present a QASM model for providing high performance distributed applications in the cloud computingPeer Reviewe

Senile cataracts and oxidative stress

AbstractIn numerous epidemiological and animal models, it can be inferred that oxidative stress is a key factor in cataract formation. Production of reactive oxygen species and reduction of endogenous antioxidants both contribute to cataract formation. In the cataractogenous process, lens proteins lose sulfhydryl groups and become thiolated or cross-linked by disulfide bonds. The resultant high molecular weight aggregates become insoluble and affect lens transparency. All these are consequences of changes in the redox state. A mixed protein-thiol and protein-protein disulfide bond precedes the morphological changes of cataract. Normally, sustained high levels of reduced glutathione provide a protective effect, while depletion of glutathione causes damage to epithelial cells and fiber cells. UV rays in the ambient environment evoke reactive oxygen species formation and also contribute to cataracts. The reduction in free UV filters and increase in their binding to lens proteins make the lens more predisposed to UV damage and oxidation. In the aqueous humor of cataract lenses, there is a decrease in antioxidant enzymes and increase in nitric oxide, which demonstrates the relationship between oxidative stress and cataracts. Though surgical intervention is the standard treatment for cataracts, experimental medical therapies for cataracts are under extensive investigation. Carnosine, a pro-drug of carnosine-N-acetylcarnosine, bendazac, ascorbic acid, and aldose reductase inhibitors are under therapeutic evaluation, and prevention of cataract formation may be possible in the future

Motor neuron-derived Thsd7a is essential for zebrafish vascular development via the Notch-dll4 signaling pathway.

BackgroundDevelopment of neural and vascular systems displays astonishing similarities among vertebrates. This parallelism is under a precise control of complex guidance signals and neurovascular interactions. Previously, our group identified a highly conserved neural protein called thrombospondin type I domain containing 7A (THSD7A). Soluble THSD7A promoted and guided endothelial cell migration, tube formation and sprouting. In addition, we showed that thsd7a could be detected in the nervous system and was required for intersegmental vessels (ISV) patterning during zebrafish development. However, the exact origin of THSD7A and its effect on neurovascular interaction remains unclear.ResultsIn this study, we discovered that zebrafish thsd7a was expressed in the primary motor neurons. Knockdown of Thsd7a disrupted normal primary motor neuron formation and ISV sprouting in the Tg(kdr:EGFP/mnx1:TagRFP) double transgenic zebrafish. Interestingly, we found that Thsd7a morphants displayed distinct phenotypes that are very similar to the loss of Notch-delta like 4 (dll4) signaling. Transcript profiling further revealed that expression levels of notch1b and its downstream targets, vegfr2/3 and nrarpb, were down-regulated in the Thsd7a morphants. These data supported that zebrafish Thsd7a could regulate angiogenic sprouting via Notch-dll4 signaling during development.ConclusionsOur results suggested that motor neuron-derived Thsd7a plays a significant role in neurovascular interactions. Thsd7a could regulate ISV angiogenesis via Notch-dll4 signaling. Thus, Thsd7a is a potent angioneurin involved in the development of both neural and vascular systems

Insights into Hypoxic Systemic Responses Based on Analyses of Transcriptional Regulation in Arabidopsis

We have adopted a hypoxic treatment system in which only roots were under hypoxic conditions. Through analyzing global transcriptional changes in both shoots and roots, we found that systemic signals may be transduced from roots to trigger responses in tissues not directly subjected to hypoxia. The molecular mechanisms of such systemic responses under flooding are currently largely unknown. Using ontological categorization for regulated genes, a systemic managing program of carbohydrate metabolism was observed, providing an example of how systemic responses might facilitate the survival of plants under flooding. Moreover, a proportion of gene expressions that regulated in shoots by flooding was affected in an ethylene signaling mutation, ein2-5. Many systemic-responsive genes involved in the systemic carbohydrate managing program, hormone responses and metabolism, ubiquitin-dependent protein degradation were also affected in ein2-5. These results suggested an important role of ethylene in mediation of hypoxic systemic responses. Genes associated with abscisic acid (ABA) biosynthesis are upregulated in shoots and down regulated in roots. An ABA signaling mutation, abi4-1, affects expression of several systemic responsive genes. These results suggested that regulation of ABA biosynthesis could be required for systemic responses. The implications of these results for the systemic responses of root-flooded Arabidopsis are discussed