The N-terminal region of the Escherichia coli WecA (Rfe) protein, containing three predicted transmembrane helices, is required for function but not for membrane insertion

The correct site for translation initiation for Escherichia coli WecA (Rfe), presumably involved in catalyzing the transfer of N-acetylglucosamine 1-phosphate to undecaprenylphosphate, was determined by using its FLAG-tagged derivatives. The N-terminal region containing three predicted transmembrane helices was found to be necessary for function but not for membrane localization of this protein.

Evaluating the impact of network density, hidden nodes and capture effect for throughput guarantee in multi-hop wireless networks

To optimize the performance of wireless networks, one needs to consider the impact of key factors such as interference from hidden nodes, the capture effect, the network density and network conditions (saturated versus non-saturated). In this research, our goal is to quantify the impact of these factors and to propose effective mechanisms and algorithms for throughput guarantees in multi-hop wireless networks. For this purpose, we have developed a model that takes into account all these key factors, based on which an admission control algorithm and an end-to-end available bandwidth estimation algorithm are proposed. Given the necessary network information and traffic demands as inputs, these algorithms are able to provide predictive control via an iterative approach. Evaluations using analytical comparison with simulations as well as existing research show that the proposed model and algorithms are accurate and effective.

Molecular modeling of N-terminal domains of NMDA-receptor. Study of ligand binding with N-terminal domains

Using the molecular-graphic complex Sybyl6.7.2, computational construction of spatial models for N-terminal domains (of NR1- and NR2B-subunits) of NMDA-receptor was conducted. On the basis of the constructed models and also CoMFA method the conclusion is made about presence of the binding site for the compounds similar to iphenprodyl in two N-terminal domains of NR1- and NR2B-subunits. The obtained data can be used for constructing new ligands.

Refractory cachexia and truth-telling about terminal prognosis; A qualitative study

The purpose of this paper is to examine the consequences that medical practitioners’ decisions about whether or not to be candid about terminal prognosis have for those suffering from refractory cachexia and their families. It presents the findings of a qualitative study which used focus groups and semi-structured interviews of a volunteer sample of doctors, nurses and dieticians in a cancer centre of a large teaching hospital in Northern Ireland. Respondents reported that some physicians tended to avoid discussing terminal prognosis in a direct manner with their patients. Nurses and dieticians tended to be reluctant to engage in conversations about weight loss with patients with cachexia. One of the reasons they reported for their lack of acknowledgement of weight loss concerned the close association between refractory cachexia and terminal prognosis. Because they viewed the telling of bad news as an exclusive prerogative of medical practitioners, they did not feel in a position to discuss cachexia because they were concerned that this had the potential to raise end-of-life issues that lay outside the boundaries of their professional role. This meant patients and their families were provided with little information about how to cope with the distressing consequences of cachexia.

Dual-Reflector Antenna with a Reflectarray Subreflector for Wide Beam Scanning Range at 120GHz

A dual-reflector antenna composed by a small reconfigurable reflectarray subreflector and a large parabolic main reflector is proposed for beam scanning application in the 120 GHz frequency band. The beam scanning is achieved by changing the phase distribution on the reflectarray surface which is supposed to contain reconfigurable cells. The phase distribution for the different beam deflecting states is obtained with a synthesis technique based on the analysis of the antenna in receive mode.

Millimetre-wave broadband wireless systems and enabling MMIC technologies

Chapter eleven on Mm-wave broadband wireless systems and enabling MMIC technologies, is contributed by Jian Zhang, Mury Thian, Guochi Huang, George Goussetis and Vincent F. Fusco, from Queen's University Belfast, UK. Millimeter wave bands provide large available bandwidths for high data rate wireless communication systems, which are envisaged to shift data throughput well in the GBps range. This capability has over past few years driven rapid developments in the technology underpinning broadband wireless systems as well as in the standardisation activity from various non-governmental consortia and the band allocation from spectrum regulators globally. This chapter provides an overview of the recent developments on V-band broadband wireless systems with the emphasis placed on enabling MMIC technologies. An overview of the key applications and available standards is presented. System-level architectures for broadband wireless applications are being reviewed. Examples of analysis, design and testing on MMIC components in SiGe BiCMOS are presented and the outlook of the technology is discussed.

Split-Ring FSS Spiral Phase Plate

This letter gives the first report of a planar phase plate structure based on frequency selective surface (FSS) technology for the generation of helical far-field radiation patterns with circular polarization properties.The unit cell of the structure comprises two orthogonal split-ring resonators designed to ensure 180$^{\circ}$ phase shift between orthogonal transmission coefficients. This property is exploited to obtain progressive rotational phase shift within the structure and thus synthesize 360$^{\circ}$ spiral phase profile. Measured far-field radiation patterns demonstrate spiral phase front generation for 10-GHz circularly polarized waves transmitted through the structure.

Molecular evolution of proadrenomedullin N-terminal 20 peptide (PAMP):evidence for gene co-option

Posttranslational processing of proadrenomedullin generates two biologically active peptides, adrenomedullin (AM) and proadrenomedullin N-terminal 20 peptide (PAMP). Sequence comparison of homologous proadrenomedullin genes in vertebrate evolution shows a high degree of stability in the reading frame for AM, whereas PAMP sequence changes rapidly. Here we investigate the functional significance of PAMP phylogenetic variation studying two of PAMP's better characterized physiological activities, angiogenic potential and antimicrobial capability, with synthetic peptides carrying the predicted sequence for human, mouse, chicken, and fish PAMP. All tested peptides induced angiogenesis when compared with untreated controls, but chicken and fish PAMP, which lack terminal amidation, were apparently less angiogenic than their human and mouse homologs. Confirming the role of amidation in angiogenesis, Gly-extended and free acid variants of human PAMP produced responses similar to the natural nonamidated peptides. In contrast, antimicrobial activity was restricted to human PAMP, indicating that this function may have been acquired at a late time during the evolution of PAMP. Interestingly, free acid human PAMP retained antimicrobial activity whereas the Gly-extended form did not. This fact may reflect the need for maintaining a tightly defined structural conformation in the pore-forming mechanism proposed for these antimicrobial agents. The evolution of PAMP provides an example of an angiogenic peptide that developed antimicrobial capabilities without losing its original function.

Application-based workload model for wireless sensor node computing platforms

Wireless sensor node platforms are very diversified and very constrained, particularly in power consumption. When choosing or sizing a platform for a given application, it is necessary to be able to evaluate in an early design stage the impact of those choices. Applied to the computing platform implemented on the sensor node, it requires a good understanding of the workload it must perform. Nevertheless, this workload is highly application-dependent. It depends on the data sampling frequency together with application-specific data processing and management. It is thus necessary to have a model that can represent the workload of applications with various needs and characteristics. In this paper, we propose a workload model for wireless sensor node computing platforms. This model is based on a synthetic application that models the different computational tasks that the computing platform will perform to process sensor data. It allows to model the workload of various different applications by tuning data sampling rate and processing. A case study is performed by modeling different applications and by showing how it can be used for workload characterization. © 2011 IEEE.

Introduction to Wireless Intrusion Detection Systems

The IDS (Intrusion Detection System) is a common means of protecting networked systems from attack or malicious misuse. The development and rollout of an IDS can take many different forms in terms of equipment, protocols, connectivity, cost and automation. This is particularly true of WIDS (Wireless Intrusion Detection Systems) which have many more opportunities and challenges associated with data transmission through an open, shared medium.
The operation of a WIDS is a multistep process from origination of an attack through to human readable evaluation. Attention to the performance of each of the processes in the chain from attack detection to evaluation is imperative if an optimum solution is to be sought. At present, research focuses very much on each discrete aspect of a WIDS with little consideration to the operation of the whole system. Taking a holistic view of the technology shows the interconnectivity and inter-dependence between stages, leading to improvements and novel research areas for investigation.
This chapter will outline the general structure of Wireless Intrusion Detection Systems and briefly describe the functions of each development stage, categorised into the following 6 areas:
• Threat Identification,
• Architecture,
• Data Collection,
• Intrusion Detection,
• Alert Correlation,
• Evaluation.
These topics will be considered in broad terms designed for those new to the area. Focus will be placed on ensuring the readers are aware of the impact of choices made at early stages in WIDS development on future stages.

A double U-slot patch antenna with dual wideband characteristics

Microstrip patch antennas are strong candidates for use in many wireless communications applications. This paper proposes the use of a patch antenna with two U-shaped slots to achieve dual band operation. A thick substrate helps broaden the individual bandwidths. The antenna is designed based on extensive IE3D simulation studies. A prototype antenna is fabricated and experimentally verified for the required performance.

The C-Terminal Variable Region Specifies the Dynamic Properties of Arabidopsis Microtubule-Associated Protein MAP65 Isotypes

The microtubule-associated protein, MAP65, is a member of a family of divergent microtubule-associated proteins from different organisms generally involved in maintaining the integrity of the central spindle in mitosis. The dicotyledon Arabidopsis thaliana and the monocotyledon rice (Oryza sativa) genomes contain 9 and 11 MAP65 genes, respectively. In this work, we show that the majority of these proteins fall into five phylogenetic clades, with the greatest variation between clades being in the C-terminal random coil domain. At least one Arabidopsis and one rice isotype is within each clade, indicating a functional specification for the C terminus. In At MAP65-1, the C-terminal domain is a microtubule binding region (MTB2) harboring the phosphorylation sites that control its activity. The At MAP65 isotypes show differential localization to microtubule arrays and promote microtubule polymerization with variable efficiency in a MTB2-dependent manner. In vivo studies demonstrate that the dynamics of the association and dissociation of different MAP65 isotypes with microtubules can vary up to 10-fold and that this correlates with their ability to promote microtubule polymerization. Our data demonstrate that the C-terminal variable region, MTB2, determines the dynamic properties of individual isotypes and suggest that slower turnover is conditional for more efficient microtubule polymerization.