On the Scalability of Addressing in Private Networks Using RPX

In recent times, the imminent lack of public IPv4 addresses has attracted the attention of both research community and industry. The cellular industry has decided to combat this problem by using IPv6 for all new terminals. However, the success of 3G network deployment will depend on the services offered to end users. Currently, almost all services reside in the public IPv4 address space, making them inaccessible to users in IPv6 networks. Thus, an intermediate translation mechanism is required. Previous studies on network address translation methods have shown that REBEKAH-IP with Port Extension (RPX) supports all types of services that can be offered to IPv6 terminals from the public IPv4 based Internet, and provides excellent scalability. However, this method suffers from an ambiguity problem which may lead to call blocking. In this paper, we present an improvement to RPX scheme in which the side effect is removed and fully scalable system. We firstly show the expected number of public IPv4 addresses utilization to the DNS of RPX server. This utilization is computed in terms of the probability of socket open requests from mobile terminals, the probability of call blocking and the estimated number of mobile terminals at the network initialization phase. The mathematical model is also provided as a guideline to determine the range of public IPv4 addresses allocated to an RPX gateway in a cellular network. In addition, the results are presented through a set of simulations. However, we proposed the RPX scheme to use a simple round robin scheduling algorithm is sub-optimal in terms of call blocking probability and further propose to use a priority queue algorithm to improve the scalability. In addition, we present extensive simulation results on the practical scalability of RPX with different traffic compositions to provide a guideline of the expected scalability in large-scale networks such as 3G networks

The Promise of Beijing: Evaluating the Impact of the 2008 Olympic Games on Air Quality

To prepare for the 2008 Olympic Games, China adopted a number of radical measures to improve air quality. Using officially reported air pollution index (API) from 2000 to 2009, we show that these measures improved the API of Beijing during and after the Games, but 60% of the effect faded away by the end of October 2009. Since the credibility of API data has been questioned, an objective and indirect measure of air quality at a high spatial resolution – aerosol optimal depth (AOD), derived using the data from the NASA satellites – was analyzed and compared with the API trend. The analysis confirms that the improvement was real but temporary and most improvement was attributable to plant closure and traffic control. Our results suggest that it is possible to achieve real environmental improvement in an authoritarian regime but the magnitude of the effect and how long it lasts depend on the political motivation behind the policy interventions.

CFD investigation of blind-tee effects on flow mixing mechanism in subsea pipelines

Blind tees are widely used in subsea pipelines to enhance the mixing conditions of oil and gas products, but their structural design still relies on experience. In this paper, a series of numerical investigations have been carried out on blind-tee pipes in order to develop an in-depth understanding of their mixing mechanism and clarify the effects of blind-tee structures on the pipe flow. Firstly, the three-dimensional flow conditions in a typical blind tee have been simulated under different Reynolds numbers to investigate the mixing mechanism. Two critical Reynolds numbers for the vortex generations in blind tees are determined in the laminar flow regime, and the fitting curves of blind-tee vorticity dissipations are obtained. Then, the geometrical parameters, including the radial size ϕ, axial length (BSL) and position of the blind section, are varied systematically to study their effects on the flow characteristics and mixing conditions. The results indicate that increasing ϕ and BSL in an appropriate range can strengthen the flow circulation and promote the fluid exchange. Finally, an optimal configuration is obtained, which can improve the mixing capacity of blind tee by 53% in terms of the volume average vorticity as compared to the typical structure.publishedVersio

Carnosol Modulates Th17 Cell Differentiation and Microglial Switch in Experimental Autoimmune Encephalomyelitis

Medicinal plants as a rich pool for developing novel small molecule therapeutic medicine have been used for thousands of years. Carnosol as a bioactive diterpene compound originated from Rosmarinus officinalis (Rosemary) and Salvia officinalis, herbs extensively applied in traditional medicine for the treatment of multiple autoimmune diseases (1). In this study, we investigated the therapeutic effects and molecule mechanism of carnosol in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Carnosol treatment significantly alleviated clinical development in the myelin oligodendrocyte glycoprotein (MOG35–55) peptide-induced EAE model, markedly decreased inflammatory cell infiltration into the central nervous system and reduced demyelination. Further, carnosol inhibited Th17 cell differentiation and signal transducer and activator of transcription 3 phosphorylation, and blocked transcription factor NF-κB nuclear translocation. In the passive-EAE model, carnosol treatment also significantly prevented Th17 cell pathogenicity. Moreover, carnosol exerted its therapeutic effects in the chronic stage of EAE, and, remarkably, switched the phenotypes of infiltrated macrophage/microglia. Taken together, our results show that carnosol has enormous potential for development as a therapeutic agent for autoimmune diseases such as MS

Nanoplasmonic Phenomena at Electronic Boundaries in Graphene

We review recent discoveries of the intriguing plasmonic phenomena at a variety of electronic boundaries (EBs) in graphene including a line of charges in graphene induced by a carbon nanotube gate, grain boundaries in chemical vapor deposited graphene films, an interface between graphene and moiré patterned graphene, an interface between graphene and bilayer graphene, and others. All these and other EBs cause plasmonic impedance mismatch at the two sides of the boundaries. Manifestations of this effect include plasmonic fringes that stem from plasmon reflections and interference. Quantitative analysis and modeling of these plasmonic fringes uncovered intriguing properties and underlying physics of the EBs. Potential plasmonic applications associated with these EBs are also briefly discussed