The simulation of stress fibre and focal adhesion development in cells on patterned substrates.

The remodelling of the cytoskeleton and focal adhesion (FA) distributions for cells on substrates with micro-patterned ligand patches is investigated using a bio-chemo-mechanical model. We investigate the effect of ligand pattern shape on the cytoskeletal arrangements and FA distributions for cells having approximately the same area. The cytoskeleton model accounts for the dynamic rearrangement of the actin/myosin stress fibres. It entails the highly nonlinear interactions between signalling, the kinetics of tension-dependent stress-fibre formation/dissolution and stress-dependent contractility. This model is coupled with another model that governs FA formation and accounts for the mechano-sensitivity of the adhesions from thermodynamic considerations. This coupled modelling scheme is shown to capture a variety of key experimental observations including: (i) the formation of high concentrations of stress fibres and FAs at the periphery of circular and triangular, convex-shaped ligand patterns; (ii) the development of high FA concentrations along the edges of the V-, T-, Y- and U-shaped concave ligand patterns; and (iii) the formation of highly aligned stress fibres along the non-adhered edges of cells on the concave ligand patterns. When appropriately calibrated, the model also accurately predicts the radii of curvature of the non-adhered edges of cells on the concave-shaped ligand patterns.     

An 18-Mb, 12.3-GB/s CMOS pipeline-burst cache SRAM with 1.54Gb/s/pin

An 18-Mbit CMOS pipeline-burst cache SRAM achieves a 12.3-Gbyte/s data transfer rate with 1.54-Gbit/s/pin I/O's. The SRAM is fabricated on a 0.18-μm CMOS technology. The 14.3×14.6-mm² SRAM chip uses a 5.59-μm², six-transistor cell. Circuit techniques used for achieving high bandwidth include fully self-timed array architecture, segmented hierarchical sensing with separated global read/write bitlines in different metal layers, a high-speed data-capture technique, a reduced-swing output buffer, and a high-sensitivity, high-bandwidth input buffer     

One-step photochemical synthesis of permanent, nonleaching, ultrathin antimicrobial coatings for textiles and plastics

Antimicrobial copolymers of hydrophobic N-alkyl and benzophenone containing polyethylenimines were synthesized from commercially available linear poly(2-ethyl-2-oxazoline), and covalently attached to surfaces of synthetic polymers, cotton, and modified silicon oxide using mild photo-cross-linking. Specifically, these polymers were applied to polypropylene, poly(vinyl chloride), polyethylene, cotton, and alkyl-coated oxide surfaces using solution casting or spray coating and then covalently cross-linked rendering permanent, nonleaching antimicrobial surfaces. The photochemical grafting of pendant benzophenones allows immobilization to any surface that contains a C-H bond. Incubating the modified materials with either Staphylococcus aureus or Escherichia coli demonstrated that the modified surfaces had substantial antimicrobial capacity against both Gram-positive and Gram-negative bacteria (>98% microbial death).     

Solving multi-objective optimal power flow using differential evolution

A differential evolution approach to solve optimal power flow problem with multiple and competing objectives is presented. Two sub-problems of optimal power flow namely active power dispatch and reactive power dispatch are considered. The problem is formulated as a nonlinear constrained true multi-objective optimisation problem with competing objectives. Constrain-domination approach have been used to handle inequality constraints, which eliminates the use of penalty factors. The performance of the proposed approach was tested on standard IEEE 30-bus system and is compared with a conventional method. The result demonstrates the capability of the proposed approach to generate diverse and well-distributed Pareto-optimal solutions.     

Antioxidant efficacy of chitosan/graphene functionalized superparamagnetic iron oxide nanoparticles

The antioxidant potential of superparamagnetic iron oxide nanoparticles functionalized with chitosan and graphene were examined in the present work. Coprecipitation technique was followed for the synthesis of iron oxide nanoparticles. Graphene-iron oxide nanocomposites were synthesized by mechanical mixing followed by the heat treatment at moderate temperature. The chitosan coated iron oxide nanoparticles were prepared by dispersing nanoparticles in chitosan solution. The nanoparticles/nanocomposites were characterized using XRD, SEM, TEM and HAADF-STEM for phase structure, morphology and elemental analysis. The superparamagnetic behavior of nanoparticles/nanocomposites were confirmed by magnetic measurements using vibrating sample magnetometry. Antioxidant efficacy of these nanoparticles/nanocomposites were investigated in terms of free radical scavenging and reducing potential using an array of in vitro assay system. Ferric reducing antioxidant power (FRAP) and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) were used for the antioxidant capacity. The investigation suggests that the graphene improves the antiradical response of iron oxide nanoparticles at higher concentration which is almost comparable to the ascorbic acid used as standard.     

Parallel state-space search for a first solution with consistent linear speedups

Consider the problem of exploring a large state-space for a goal state where although many such states may exist in the state-space, finding any one state satisfying the requirements is sufficient. All the methods known until now for conducting such search in parallel using multiprocessors fail to provide consistent linear speedups over sequential execution. The speedups vary between sublinear to superlinear and from one execution to another. Further, adding more processors may sometimes lead to a slow-down rather than speedup, giving rise to speedup anomalies reported in literature. We present a prioritizing strategy which yields consistent speedups that are close toP withP processors, and that monotonically increase with the additon of processors. This is achieved by keeping the total number of nodes expanded during parallel search very close to that of a sequential search. In addition, the strategy requires substantially smaller memory relative to other methods. The performance of this strategy is demonstrated on a multiprocessor with several state-space search problems.This research has been supported in part by the National Science Foundation under Contract No. CCR-89-02496.     

Influence of material microstructure on grindability of bearing steel

Innovative new materials and microstructures are being continually developed to meet increasingly challenging applications. These newly developed microstructures pose significant challenges in terms of grindability and component distortion. This fundamental study sheds light on the grindability of microstructure variations of through hardened A485–1 grade steel. Results indicate that the phase composition and carbide distribution significantly influence grindability which is characterized in terms of specific grinding energy, G-ratio and part distortion. The study also demonstrates that the numerically quantified carbide distribution exhibits a strong correlation to grindability when phase compositions are similar.     

Efficient Algorithm for Identification and Cache Based Discovery of Cloud Services

Mobile Networks and Applications - Efficient resource identification and discovery is the primary requirements for cloud computing services, as it assists in scheduling and managing of cloud...     

Perception of safety of cyclists in Dublin City

In recent years, cycling has been recognized and is being promoted as a sustainable mode of travel. The perception of cycling as an unsafe mode of travel is a significant obstacle in increasing the mode share of bicycles in a city. Hence, it is important to identify and analyze the factors which influence the safety experiences of the cyclists in an urban signalized multi-modal transportation network. Previous researches in the area of perceived safety of cyclists primarily considered the influence of network infrastructure and operation specific variables and are often limited to specific locations within the network. This study explores the factors that are expected to be important in influencing the perception of safety among cyclists but were never studied in the past. These factors include the safety behavior of existing cyclists, the users of other travel modes and their attitude toward cyclists, facilities and network infrastructures applicable to cycling as well as to other modes in all parts of an urban transportation network. A survey of existing cyclists in Dublin City was conducted to gain an insight into the different aspects related to the safety experience of cyclists. Ordered Logistic Regression (OLR) and Principal Component Analysis (PCA) were used in the analysis of survey responses. This study has revealed that respondents perceive cycling as less safe than driving in Dublin City. The new findings have shown that the compliance of cyclists with the rules of the road increase their safety experience, while the reckless and careless attitudes of drivers are exceptionally detrimental to their perceived safety. The policy implications of the results of analysis are discussed with the intention of building on the reputation of cycling as a viable mode of transportation among all network users.     

Accurate Linewidth Measurements in Aperture Limited In-line Fraunhofer Holography

Abstract

Methods for accurate width analysis of line objects in aperture limited in-line Fraunhofer holography are described. One approach involves size correction utilizing the nature of the error commonly introduced. The other technique used involves measuring the width at a certain normalized intensity and not at the apparent edge. The general background is discussed in detail using an opaque object model.