Density profiles in the raise and peel model with and without a wall; physics and combinatorics

We consider the raise and peel model of a one-dimensional fluctuating interface in the presence of an attractive wall. The model can also describe a pair annihilation process in disordered unquenched media with a source at one end of the system. For the stationary states, several density profiles are studied using Monte Carlo simulations. We point out a deep connection between some profiles seen in the presence of the wall and in its absence. Our results are discussed in the context of conformal invariance ( c = 0 theory). We discover some unexpected values for the critical exponents, which are obtained using combinatorial methods. We have solved known ( Pascal`s hexagon) and new (split-hexagon) bilinear recurrence relations. The solutions of these equations are interesting in their own right since they give information on certain classes of alternating sign matrices.

A conformal invariant growth model

We present a one-parameter extension of the raise and peel one-dimensional growth model. The model is defined in the configuration space of Dyck (RSOS) paths. Tiles from a rarefied gas hit the interface and change its shape. The adsorption rates are local but the desorption rates are non-local; they depend not only on the cluster hit by the tile but also on the total number of peaks (local maxima) belonging to all the clusters of the configuration. The domain of the parameter is determined by the condition that the rates are non-negative. In the finite-size scaling limit, the model is conformal invariant in the whole open domain. The parameter appears in the sound velocity only. At the boundary of the domain, the stationary state is an adsorbing state and conformal invariance is lost. The model allows us to check the universality of non-local observables in the raise and peel model. An example is given.

Properties of lipophilic nucleoside monolayers at the air-water interface

The capability of self-assembly and molecular recognition of biomolecules is essential for many nanotechnological applications, as in the use of alkyl-modified nucleosides and oligonucleotides to increase the cellular uptake of DNA and RNA. In this study, we show that a lipophilic nucleoside, which is an isomer mixture of 2`-palmitoyluridin und 3`-palmitoyluridin, forms Langmuir monolayers and Langmuir-Blodgett films as a typical amphiphile, though with a smaller elasticity. The nucleoside may be incorporated into dipalmitoyl phosphatidyl choline (DPPC) monolayers that serve as a simplified cell membrane model. The molecular-level interactions between the nucleoside and DPPC led to a remarkable condensation of the mixed monolayer, which affected both surface pressure and surface potential isotherms. The morphology of the mixed monolayers was dominated by the small domains of the nucleoside. The mixed monolayers could be deposited onto solid substrates as a one-layer Langmuir Blodgett film that displayed UV-vis absorption spectra typical of aggregated nucleosides owing to the interaction between the nucleoside and DPPC. The formation of solid films with DNA building blocks in the polar heads may open the way for devices and sensors be produced to exploit their molecular recognition properties. (C) 2010 Elsevier B.V. All rights reserved.

Disruption of Saccharomyces cerevisiae by Plantaricin 149 and investigation of its mechanism of action with biomembrane model systems

The action of a synthetic antimicrobial peptide analog of Plantaricin 149 (Pln149a) against Saccharomyces cerevisiae and its interaction with biomembrane model systems were investigated. Pln149a was shown to inhibit S. cerevisiae growth by more than 80% in YPD medium, causing morphological changes in the yeast wall and remaining active and resistant to the yeast proteases even after 24 h of incubation. Different membrane model systems and carbohydrates were employed to better describe the Pln149a interaction with cellular components using circular dichroism and fluorescence spectroscopies, adsorption kinetics and surface elasticity in Langmuir monolayers. These assays showed that Pln149a does not interact with either mono/polysaccharides or zwitterionic LUVs, but is strongly adsorbed to and incorporated into negatively charged surfaces, causing a conformational change in its secondary structure from random-coil to helix upon adsorption. From the concurrent analysis of Pln149a adsorption kinetics and dilatational surface elasticity data, we determined that 2.5 mu M is the critical concentration at which Pln149a will disrupt a negative DPPG monolayer. Furthermore, Pln149a exhibited a carpet-like mechanism of action, in which the peptide initially binds to the membrane, covering its surface and acquiring a helical structure that remains associated to the negatively charged phospholipids. After this electrostatic interaction, another peptide region causes a strain in the membrane, promoting its disruption. (C) 2009 Elsevier B.V. All rights reserved.

Electrochemical studies of the interface Fe/0.5 mol L(-1) H(2)SO(4) in the presence of benzotriazole and tolytriazole

The effect of benzotriazole (BTAH) and tolytriazole (TTAH) on the electrochemical behaviour of the Fe/0.5 mol L(-1) H(2)SO(4) interface at 25 degrees C was studied using cronopotentiometry, anodic and cathodic polarization curves and electrochemical impedance spectroscopy. BTAH and TTAH are inhibitors of anodic iron dissolution and the subsequent hydrogen evolution in 0.5 mol L(-1) H(2)SO(4) medium. Mass transport is an important step in the anodic process of inhibitive film formation. Electrochemical impedance spectroscopy was used to investigate the iron dissolution mechanism in the presence of the inhibitors and showed that BTAH and TTAH are adsorbed on the iron surface, thereby changing its dissolution mechanism in sulfate media. Starting from an iron dissolution model, it was possible to suggest two different mechanisms for iron dissolution in 0.5 mol L(-1) H(2)SO(4) containing BTAH or TTAH that involve a complex Fe(II)-inhibitor. (C) 2009 Elsevier B.V. All rights reserved

QoS-aware model driven architecture through the UML and CIM

The specification of Quality of Service (QoS) constraints over software design requires measures that ensure such requirements are met by the delivered product. Achieving this goal is non-trivial, as it involves, at least, identifying how QoS constraint specifications should be checked at the runtime. In this paper we present an implementation of a Model Driven Architecture (MDA) based framework for the runtime monitoring of QoS properties. We incorporate the UML2 superstructure and the UML profile for Quality of Service to provide abstract descriptions of component-and-connector systems. We then define transformations that refine the UML2 models to conform with the Distributed Management Taskforce (DMTF) Common Information Model (CIM) (Distributed Management Task Force Inc. 2006), a schema standard for management and instrumentation of hardware and software. Finally, we provide a mapping the CIM metamodel to a .NET-based metamodel for implementation of the monitoring infrastructure utilising various .NET features including the Windows Management Instrumentation (WMI) interface.

A web-DB model on multicast and anycast

Most of the current web-based database systems suffer from poor performance, complicated heterogeneity, and synchronization issues. In this paper, we propose a novel mechanism for web-based database system on multicast and anycast protocols to deal with these issues. In the model, we put a castway, a network interface for database server, between database server and Web server. Castway deals with the multicast and anycast requests and responses. We propose a requirement-based server selection algorithm and an atomic multicast update algorithm for data queries and synchronizations. The model is independent from the Internet environment, it can synchronise the databases efficiently and automatically. Furthermore, the model can reduce the possibility of transaction deadlocks.

The interface of acute and aged care: the role of the nurse in provincial area

Objective: This study was to investigate issues that arose from pre-admission to post-discharge, for people in Toowoomba, Queensland over the age of 65 admitted to an acute facility. This paper concentrates on a significant concern that emerged from the latge amount of data collected during this project, that is, the role of the nurse in the continuum of health care involving elderly people.

Method: The study involved a multi-site, multi-agency and multi-method (qualitative and quantitative) approach. Data was collected from regional service providers, the Department of Health and Aged Care (DHAC), the Australian Bureau of Statistics (ABS), Home and Community Care (HACC), the Aged Care Assessment Team (ACAT), elderly people who had been discharged from regional hospitals and their carers, residents of regional aged care facilities, area health professionals and elderly regional hospital inpatients.

Results: The data indicated that nurses in this provincial area currently play a limited role in preadmission planning, being mostly concerned with elective surgery, especially joint replacements. While nurses deliver the majority of care during hospitalisation, they do not appear to be cognizant of the needs of the elderly regarding post-acute discharge.

Conclusion: The recent introduction of the model of nurse case management in the acute sector appears to be a positive development that will streamline and optimise the health care of the elderly across the continuum in the Toowoomba area. The paper recommends some strategies, such as discharge liaison nurses based in Emergency Departments and the expansion of the nurse case management role, which would optimise care for the elderly person at the interface of care.

The dual technique model within case study approaches to cross-cultural management research in China

This paper advocates the effectiveness of a dual technique model of interviewing, which combines narrative and depth interview techniques, within the case study method in a cross-cultural management research setting, an Australian MNC operating in China. The case study is acknowledged to be a highly appropriate method for gaining insight into the complicated area of cross-cultural management enquiry in order to generate new theories. In this context, we propose a model which combines the narrative and the depth interview techniques in the interview process, and have illustrated its usefulness with material drawn from the China-Australia cross-cultural research interface.

After establishing the rationale for the model, the discussion focuses on the practicalities of applying it in interviews, in relation to the preparation, warm-up and trust building phases, and in the exercise of personal interviewing skills in cross-cultural research, in this case, the advantage of the interviewer being bilingual.

Towards the development of a conceptual design management model for remote sites

Remote and environmentally sensitive sites present unique challenges for participants involved in the design and construction process. Worldwide advances in information technology coupled with improved site accessibility and manageability has enabled the construction industry to undertake such projects with greater ease. Furthermore, research on information technology in construction has begun to focus our attentions on our increased ability to work virtually in distributed teams. These remote sites have a range of development potential as clients have varied interests including; tourism, scientific investigation and resource exploration and processing which impact upon the management of the design process. These sites pose unique challenges to the project teams and in particular for the management of project design. The conceptual design phase is often marked by an iterative and creative process, which tends to be a sociologically oriented world where designers respond to a range of functional, aesthetic, environmental and even spiritual concerns. Strategic decisions made during the briefing and conceptual design stage may impact upon construction logistics and sustainability. Detailed design for construction tends to be a production oriented world. There is a significant body of literature that addresses the application of lean thinking to improving the interface between detailed design and construction production. There is little literature that takes a holistic view of design management for remote sites. The lean design management field of research has much to contribute to the design management of these projects. The review of the literature indicated that much of the lean thinking has been primarily concerned with sequential production. However, lean thinking is based upon principles of flow and value, which is also conducive to the complex process involved in design management for remote sites. A conceptual model is developed that considers both the production and sociological approaches to design management, in response to the peculiar demands of the site and their project teams.

Pulse-lavage brushing followed by hydrogen peroxide-gauze packing for bone-bed preparation in cemented total hip arthroplasty : a bovine model

To compare the effectiveness of pulse-lavage brushing followed by hydrogen peroxide-gauze packing with either technique alone or normal-saline irrigation in bone-bed preparation for cemented total hip arthroplasty. 44 fresh-frozen ox femoral canals were prepared for cemented total hip arthroplasty using 4 techniques: normal-saline irrigation, pulse-lavage brushing, hydrogen peroxide-soaked gauze packing, and a combination of the latter 2 techniques. The maximum tensile pull-out force required to separate the prosthesis from the femoral canal was measured as an indicator of the strength of the cement-bone interface. The mean pull-out force to separate the prosthesis from the femoral canal was significantly higher in specimens prepared with pulse-lavage brushing followed by hydrogen peroxide-soaked gauze packing or pulse-lavage brushing alone than those prepared with normal-saline irrigation or hydrogen peroxide-soaked gauze packing alone 300(p<0.001). Pulse-lavage brushing is more effective at cleansing the femoral canal and increasing mechanical strength at the cement-bone interface than preparation with normal-saline irrigation or hydrogen peroxide-soaked gauze packing.

Good lives model applied to a forensic population

According to the good lives model (GLM) all human beings seek primary goods (i.e., activities or experiences that benefit them) and offending reflects attempts to pursue these goods in ways that are unacceptable to society and damaging to the individual and others. The aim of this article was to explore how the GLM can be developed for use with a forensic population, a heterogeneous group of individuals whose common feature is the interface of the criminal justice and mental health systems. The conceptual, clinical and philosophical implications of using the good lives model of forensic mental health (GLM-FM) are explored. Three case studies are used to illustrate the ways in which the enriched model can provide a holistic approach to conceptualizing offending that occurs in the context of mental illness and in guiding treatment planning. It is suggested that the augmented model provides a clinically flexible and ethically sound framework for formulating treatment issues for forensic patients.

Double layer structure of ionic liquids at the Au(111) electrode interface : an atomic force microscopy investigation

The double layer structure of two ionic liquids (ILs), 1-butyl-1- methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate ([Py ₁,₄]FAP) and 1-ethyl-3-methylimidazolium tris(pentafluoroethyl) trifluorophosphate ([EMIm]FAP) at the polarized Au(111) electrode interface is probed using Atomic Force Microscopy force measurements. The force-separation profiles suggest a multilayered morphology is present at the electrified Au(111)-IL interface, with more near surface layers detected at higher potentials. At the (slightly negative) open circuit potential, multiple ion layers are present, and the innermost layer, in contact with the Au(111) surface, is enriched in the cation due to electrostatic adsorption. Upon applying negative electrode potentials (-1.0 V, -2.0 V), stronger IL near surface structure is detected: both the number of ion layers and the force required to rupture these layers increases. Positive electrode potentials (+1.0 V, +2.0 V) also enhance IL near surface structure, but not as much as negative potentials, because surface-adsorbed anions are less effective at templating structure in subsequent layers than cations. This interfacial structure is not consistent with a double layer in the Stern-Gouy-Chapman sense, as there is no diffuse layer. The structure is consistent with a capicitative double-layer model, with a very small separation distance between the planes of charge.

Recruitment of class I hydrophobins to the air : water interface initiates a multi-step process of functional amyloid formation

Class I fungal hydrophobins form amphipathic monolayers composed of amyloid rodlets. This is a remarkable case of functional amyloid formation in that a hydrophobic:hydrophilic interface is required to trigger the self-assembly of the proteins. The mechanism of rodlet formation and the role of the interface in this process have not been well understood. Here, we have studied the effect of a range of additives, including ionic liquids, alcohols, and detergents, on rodlet formation by two class I hydrophobins, EAS and DewA. Although the conformation of the hydrophobins in these different solutions is not altered, we observe that the rate of rodlet formation is slowed as the surface tension of the solution is decreased, regardless of the nature of the additive. These results suggest that interface properties are of critical importance for the recruitment, alignment, and structural rearrangement of the amphipathic hydrophobin monomers. This work gives insight into the forces that drive macromolecular assembly of this unique family of proteins and allows us to propose a three-stage model for the interface-driven formation of rodlets.

Spectral element model updating for damage identification using clonal selection algorithm

A spectral element model updating procedure is presented to identify damage in a structure using Guided wave propagation results. Two damage spectral elements (DSE1 and DSE2) are developed to model the local (cracks in reinforcement bar) and global (debonding between reinforcement bar and concrete) damage in one-dimensional homogeneous and composite waveguide, respectively. Transfer matrix method is adopted to assemble the stiffness matrix of multiple spectral elements. In order to solve the inverse problem, clonal selection algorithm is used for the optimization calculations. Two displacement-based functions and two frequency-based functions are used as objective functions in this study. Numerical simulations of wave propagation in a bare steel bar and in a reinforcement bar without and with various assumed damage scenarios are carried out. Numerically simulated data are then used to identify local and global damage of the steel rebar and the concrete-steel interface using the proposed method. Results show that local damage is easy to be identified by using any considered objective function with the proposed method while only using the wavelet energy-based objective function gives reliable identification of global damage. The method is then extended to identify multiple damages in a structure. To further verify the proposed method, experiments of wave propagation in a rectangular steel bar before and after damage are conducted. The proposed method is used to update the structural model for damage identification. The results demonstrate the capability of the proposed method in identifying cracks in steel bars based on measured wave propagation data.