Analysis of the Response of a One-Storey One-Bay Steel Frame to Blast

In recent years, there has been a considerable increase in perceived risks of blast loading attacks or similar incidents on structures. Blast design is therefore a necessary aspect of the design for building structures globally and as such building design must adapt accordingly. Presented herein is an attempt to determine the numerical response of a seismically designed single-degree-of-freedom (SDOF) structure to blast loading. The SDOF model in the form of a portal frame was designed to withstand a typical seismic occurrence in Northern Trinidad. Blast loads caused by applying a 500 kg charge weight of TNT at standoff distances of 45 m, 33 m, and 20 m were then applied to the model. The blast loading on the frame was determined using empirical methods. The analytical study showed that the seismically designed SDOF plane frame model entered the plastic region during the application of the blast load occurring up to the critical standoff distance.

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Enhancing Energy Efficiency of Wireless Sensor Network through the Design of Energy Efficient Routing Protocol

Wireless Sensor Network (WSN) is known to be a highly resource constrained class of network where energy consumption is one of the prime concerns. In this research, a cross layer design methodology was adopted to design an energy efficient routing protocol entitled “Position Responsive Routing Protocol” (PRRP). PRRP is designed to minimize energy consumed in each node by (1) reducing the amount of time in which a sensor node is in an idle listening state and (2) reducing the average communication distance over the network. The performance of the proposed PRRP was critically evaluated in the context of network lifetime, throughput, and energy consumption of the network per individual basis and per data packet basis. The research results were analyzed and benchmarked against the well-known LEACH and CELRP protocols. The outcomes show a significant improvement in the WSN in terms of energy efficiency and the overall performance of WSN.

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Nanomechanical Characterization of Amyloid Fibrils Using Single-Molecule Experiments and Computational Simulations

Amyloid fibrils have recently received much attention due to not only their important role in disease pathogenesis but also their excellent mechanical properties, which are comparable to those of mechanically strong protein materials such as spider silk. This indicates the necessity of understanding fundamental principles providing insight into how amyloid fibrils exhibit the excellent mechanical properties, which may allow for developing biomimetic materials whose material (e.g., mechanical) properties can be controlled. Here, we describe recent efforts to characterize the nanomechanical properties of amyloid fibrils using computational simulations (e.g., atomistic simulations) and single-molecule experiments (e.g., atomic force microscopy experiments). This paper summarizes theoretical models, which are useful in analyzing the mechanical properties of amyloid fibrils based on simulations and experiments, such as continuum elastic (beam) model, elastic network model, and polymer statistical model. In this paper, we suggest how the nanomechanical properties of amyloid fibrils can be characterized and determined using computational simulations and/or atomic force microscopy experiments coupled with the theoretical models.

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Interaction-Aware Video Community-Based Content Delivery in Wireless Mobile Networks

The increase in the demand of content quality and the number of mobile users brings new challenges for the multimedia streaming services in wireless mobile networks. The virtual community technologies are promising by grouping the users with common characteristics to get the gains in the performance of resource lookup and system scalability. In this paper, we propose a novel interaction-aware video community-based content delivery (IVCCD) in wireless mobile networks. IVCCD collects and analyzes the interaction information between users to construct user interaction model and further capture the common characteristics in the request and delivery of video content. IVCCD employs a partition-based community discovery scheme to group the mobile users in terms of the common characteristics and uses a community member management mechanism and a resource sharing scheme to achieve low-cost community maintenance and high searching performance. Extensive tests show how IVCCD achieves much better performance results in comparison with other state-of-the-art solutions.

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Expressions of Matrix Metalloproteinases 2, 7, and 9 in Carcinogenesis of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly fatal disease, usually diagnosed in an advanced stage which gives a slight chance of recovery. Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that participate in tissue remodeling and stimulate neovascularization and inflammatory response. The aim of the study was to evaluate the expression of MMP-2, MMP-7, and MMP-9 in normal ducts, tumor pancreatic adenocarcinoma cells, and peritumoral stroma in correlation with clinicohistopathological parameters. The study material was obtained from 29 patients with pancreatic ductal adenocarcinoma. The expressions of MMP-2, MMP-7, and MMP-9 were performed by immunohistochemical technique. Microvessel density (MVD) was visualized by special immunostaining. The expressions of MMP-2, MMP-7, and MMP-9 were mainly observed in tumor cells and peritumoral stroma. MMP-2 expression in cancer cells was correlated with female gender, stronger inflammation, and histopathological type of cancer (, ; , ; , , resp.). The expression of MMP-7 in tumor cells was found to positively correlate with the presence of necrosis and negatively correlate with MVD (, ; , ). We also showed that positive MMP-9 expression in tumor cells was associated with MVD (, ); however, it was not statistically significant. Our results demonstrate that MMP-2, MMP-7, and MMP-9 expressions correlate with various morphological features of the PDAC tumor such as inflammation, necrosis, and formation of the new blood vessels.

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Novel Robust Exponential Stability of Markovian Jumping Impulsive Delayed Neural Networks of Neutral-Type with Stochastic Perturbation

The robust exponential stability problem for a class of uncertain impulsive stochastic neural networks of neutral-type with Markovian parameters and mixed time-varying delays is investigated. By constructing a proper exponential-type Lyapunov-Krasovskii functional and employing Jensen integral inequality, free-weight matrix method, some novel delay-dependent stability criteria that ensure the robust exponential stability in mean square of the trivial solution of the considered networks are established in the form of linear matrix inequalities (LMIs). The proposed results do not require the derivatives of discrete and distributed time-varying delays to be 0 or smaller than 1. Moreover, the main contribution of the proposed approach compared with related methods lies in the use of three types of impulses. Finally, two numerical examples are worked out to verify the effectiveness and less conservativeness of our theoretical results over existing literature.

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Registration Accuracy of CT/MRI Fusion for Localisation of Deep Brain Stimulation Electrode Position: An Imaging Study and Systematic Review

Background: Postoperative imaging is essential for verifying electrode location in patients undergoing deep brain stimulation (DBS). MRI offers better visualisation of brain targets, but concerns about adverse events have limited its use. Preoperative stereotactic MRI fused with a postoperative stereotactic CT, demonstrating the electrode position, is now widely used. Objectives: The aims of this study were to: (1) evaluate the accuracy of image registration using Neuroinspire, and (2) undertake a systematic review of the literature on CT/MRI fusion techniques to ascertain the accuracy of other software packages. Methods: Twenty patients who underwent bilateral subthalamic nucleus DBS for Parkinson's disease were selected. The postoperative CT was registered and fused with the preoperative MRI using Neuroinspire. The position of each electrode tip was determined in stereotactic coordinates both in the (unfused) postoperative CT and the fused CT/MRI. The difference in tip position was used to evaluate the registration accuracy. Results: The mean error ± SD of CT/MRI fusion using Neuroinspire was 0.25 ± 0.15, 0.33 ± 0.26 and 0.46 ± 0.55 mm in lateral, anteroposterior and vertical axes. A systematic review suggested that CT/MRI registration with Neuroinspire is more accurate than that achieved with other tested CT/MRI fusion algorithms. Conclusion: CT/MRI fusion for localisation of electrode placement offers an accurate, reliable and safe modality for assessing electrode location.
Stereotact Funct Neurosurg 2016;94:159-163

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