Bandwidth Provisioning Architecture In Backhaul

The Metro Ethernet Forum has defined a set of Ethernet Virtual Connection services that are adopted to provide scalable Ethernet transport for mobile backhaul. However, these services usually address single cell site backhaul per UNI ha ndoff, not considering statistical multiplexing gain at a hub site which aggregates backhaul traffics of multiple cell sites backhaul pipe. This paper proposed an efficient carrier Ethernet bandwidth provisioning architecture for mobile backhaul with cellular cluster . A statisti cal estimation scheme has been developed for deriving a safe overbooking factor at a given U ser - N network - Interface . Then a n efficient QinQ transport architecture w as proposed to support bandwidth sharing in cellular cluster with overbooked backhaul bandwidth in carrier Ethernet. Experimental data analysis have showed that our new schemes can benefit mobile operators in resource utilization efficiency, carrier Ethernet cost saving and backhaul performance

SiteFind: A software tool for introducing a restriction site as a marker for successful site-directed mutagenesis

BACKGROUND: Site-directed mutagenesis is a widely-used technique for introducing mutations into a particular DNA sequence, often with the goal of creating a point mutation in the corresponding amino acid sequence but otherwise leaving the overall sequence undisturbed. However, this method provides no means for verifying its success other than sequencing the putative mutant construct: This can quickly become an expensive method for screening for successful mutations. An alternative to sequencing is to simultaneously introduce a restriction site near the point mutation in manner such that the restriction site has no effect on the translated amino acid sequence. Thus, the novel restriction site can be used as a marker for successful mutation which can be quickly and easily assessed. However, finding a restriction site that does not disturb the corresponding amino acid sequence is a time-consuming task even for experienced researchers. A fast and easy to use computer program is needed for this task. RESULTS: We wrote a computer program, called SiteFind, to help us design a restriction site within the mutation primers without changing the peptide sequence. Because of the redundancy of genetic code, a given peptide can be encoded by many different DNA sequences. Since the list of possible restriction sites for a given DNA sequence is not always obvious, SiteFind automates this task. The number of possible sequences a computer program must search through increases exponentially as the sequence length increases. SiteFind uses a novel "moving window" algorithm to reduce the number of possible sequences to be searched to a manageable level. The user enters a nucleotide sequence, specifies what amino acid residues should be changed in the mutation, and SiteFind generates a list of possible restriction sites and what nucleotides must be changed to introduce that site. As a demonstration of its use, we successfully generated a single point mutation and a double point mutation in the wild-type sequence for Krüppel-like factor 4, an epithelium-specific transcription factor. CONCLUSION: SiteFind is an intuitive, web-based program that enables the user to introduce a novel restriction site into the mutated nucleotide sequence for use as a marker of successful mutation. It is freely available fro

An Approach to Model Earth Conductivity Structures with Lateral Changes for Calculating Induced Currents and Geoelectric Fields during Geomagnetic Disturbances

During geomagnetic disturbances, the telluric currents which are driven by the induced electric fields will flow in conductive Earth. An approach to model the Earth conductivity structures with lateral conductivity changes for calculating geoelectric fields is presented in this paper. Numerical results, which are obtained by the Finite Element Method (FEM) with a planar grid in two-dimensional modelling and a solid grid in three-dimensional modelling, are compared, and the flow of induced telluric currents in different conductivity regions is demonstrated. Then a three-dimensional conductivity structure is modelled and the induced currents in different depths and the geoelectric field at the Earth’s surface are shown. The geovoltages by integrating the geoelectric field along specific paths can be obtained, which are very important regarding calculations of geomagnetically induced currents (GIC) in ground-based technical networks, such as power systems

Protein Separation and Label-Free Detection on Supported Lipid Bilayers

Membrane-bound proteins and charged lipids are separated based on their charge-to-size ratio by electrophoretic-electroosmotic focusing (EEF) method on supported lipid bilayers (SLBs). EEF uses opposing electrophoretic and electroosmotic forces to focus and separate proteins and lipids into narrow bands from an initially homogeneous mixture. Membrane-associated species were focused into specific positions within the SLB in a highly repeatable fashion. The steady-state focusing positions of the proteins could be predicted and controlled by tuning experimental conditions, such as buffer pH, ionic strength, electric field and temperature. Careful tuning of the variables should enable one to separate mixtures of membrane proteins with only subtle differences. The EEF technique was found to be an effective way to separate protein mixtures with low initial concentrations and it overcame diffusive peak broadening problem. A "SLB differentiation" post-separation SLB treatment method was also developed by using magnetic particles to rapidly slice the whole SLB into many small patches after electrophoretic separation, while keeping the majority of materials on surface and avoiding the use of chemical reactions. Label-free detection techniques were also developed based on EEF on SLBs. First, a new separation based label-free detection method was developed based on the change of focusing position of fluorescently labeled ligands. This technique is capable of simultaneous detecting multiple protein competitive binding on the same ligand on SLBs. Low concentration protein can be detected in the presence of interfering proteins and high concentration of BSA. The fluorescent ligands were moved to different focusing positions in a charged SLB patch by different binding proteins. Both free ligand and protein bound ligand concentrations were obtained. Therefore, both protein identity and quantity information were obtained simultaneously. Second, the focusing position of fluorescent biomarkers on SLB was used to monitor the phospholipase D catalyzed hydrolysis of phosphatidylcholine (PC) to form phosphatidic acid (PA), which is involved with the change of charge on the phospholipids. The focusing position of fluorescent membrane-bound biomarker in the EEF experiment is directly determined by the negative charge density on SLB. Other enzyme reactions involved with the change of phospholipids charge can be monitored in a label-free fashion in a similar way