Reversible active switching of the mechanical properties of a peptide film at a fluid-fluid interface

Designer peptides have recently been developed as building blocks for novel self-assembled materials with stimuli-responsive properties. To date, such materials have been based on self-assembly in bulk aqueous solution or at solid-fluid interfaces. We have designed a 21-residue peptide, AM1, as a stimuli-responsive surfactant that switches molecular architectures at a fluid-fluid interface in response to changes in bulk aqueous solution composition. In the presence of divalent zinc at neutral pH, the peptide forms a mechanically strong 'film state'. In the absence of metal ions or at acid pH, the peptide adsorbs to form a mobile 'detergent state'. The two interfacial states can be actively and reversibly switched. Switching between the two states by a change in pH or the addition of a chelating agent leads to rapid emulsion coalescence or foam collapse. This work introduces a new class of surfactants that offer an environmentally friendly approach to control the stability of interfaces in foams, emulsions and fluid-fluid interfaces more generally.

Knowledge maintenance and the frame problem

Knowledge maintenance is a major challenge for both knowledge management and the Semantic Web. Operating over the Semantic Web, there will be a network of collaborating agents, each with their own ontologies or knowledge bases. Change in the knowledge state of one agent may need to be propagated across a number of agents and their associated ontologies. The challenge is to decide how to propagate a change of knowledge state. The effects of a change in knowledge state cannot be known in advance, and so an agent cannot know who should be informed unless it adopts a simple ‘tell everyone – everything’ strategy. This situation is highly reminiscent of the classic Frame Problem in AI. We argue that for agent-based technologies to succeed, far greater attention must be given to creating an appropriate model for knowledge update. In a closed system, simple strategies are possible (e.g. ‘sleeping dog’ or ‘cheap test’ or even complete checking). However, in an open system where cause and effect are unpredictable, a coherent cost-benefit based model of agent interaction is essential. Otherwise, the effectiveness of every act of knowledge update/maintenance is brought into question.

The development of calibration and adaptive filtering procedures for neuromagnetic studies of human visual function

This thesis first considers the calibration and signal processing requirements of a neuromagnetometer for the measurement of human visual function. Gradiometer calibration using straight wire grids is examined and optimal grid configurations determined, given realistic constructional tolerances. Simulations show that for gradiometer balance of 1:104 and wire spacing error of 0.25mm the achievable calibration accuracy of gain is 0.3%, of position is 0.3mm and of orientation is 0.6°. Practical results with a 19-channel 2nd-order gradiometer based system exceed this performance. The real-time application of adaptive reference noise cancellation filtering to running-average evoked response data is examined. In the steady state, the filter can be assumed to be driven by a non-stationary step input arising at epoch boundaries. Based on empirical measures of this driving step an optimal progression for the filter time constant is proposed which improves upon fixed time constant filter performance. The incorporation of the time-derivatives of the reference channels was found to improve the performance of the adaptive filtering algorithm by 15-20% for unaveraged data, falling to 5% with averaging. The thesis concludes with a neuromagnetic investigation of evoked cortical responses to chromatic and luminance grating stimuli. The global magnetic field power of evoked responses to the onset of sinusoidal gratings was shown to have distinct chromatic and luminance sensitive components. Analysis of the results, using a single equivalent current dipole model, shows that these components arise from activity within two distinct cortical locations. Co-registration of the resulting current source localisations with MRI shows a chromatically responsive area lying along the midline within the calcarine fissure, possibly extending onto the lingual and cuneal gyri. It is postulated that this area is the human homologue of the primate cortical area V4.

The influence of context on the strategic decision-making process:a review of the literature

This paper critically reviews the strategic decision-making process literature, with a specific focus on the effects of context. Context refers to the top management team, strategic decision-specific characteristics, the external environment and firm characteristics. This literature review also develops an illustrative framework that incorporates these four different categories of contextual variables that influence the strategic decision-making process. As a result of the variety and pervasiveness of contextual variables featured within the literature, a comprehensive and up-to-date review is essential for organizing and synthesizing the extant literature to explicate an agenda for future research. The purpose of this literature review is threefold: first, to critically review the strategic decision-making process literature to highlight the underlying themes, issues, tensions and debates in the field; second, to identify the opportunities for future theory development; and third, to state the methodological implications arising from this review. © 2013 British Academy of Management and John Wiley & Sons Ltd.

Studies on the relative stabilities of Mn(II) and Mn(III) in complexes with N4O2 donor environments:crystal structures of [Mn(pybzhz)2] and [Mn(Ophsal)(imzH)2] ClO4 (pybzhz = N-(benzoyl)-N-(picolinylidene) hydrazine, Ophsal = N,N-o-phenylenebis(salicylideneimine), imzH = imidazole)

Five manganese complexes in an N 4O 2 donor environment have been prepared. Four of the compounds involve aroyl hydrazone as ligands and manganese is in a +2 oxidation state. The fifth compound was prepared using N,Nprime-o-phenylenebis(salicylideneimine) and imidazole as ligands where manganese is present in +3 oxidation state. X-ray crystal structure of one Mn +2 compound and the Mn +3 compound was determined. The relative stabilities of the Mn +2 and Mn +3 oxidation states were analyzed using the structural data and MO calculations. Manganese(II) complexes of four aroyl hydrazone ligands were prepared and characterized by different physicochemical techniques. The complexes are of the type Mn(L) 2, where L stands for the deprotonated hydrazone ligand. One of the compounds, Mn(pybzhz) 2, was also characterized by single crystal structure determination. In all these complexes, the Mn(II) is in an N 4O 2 donor environment and the Mn(II) center cannot be oxidized either chemically or electrochemically. However, when another ligand Ophsal is used to give the compound [Mn(Ophsal)(imzH) 2]ClO 4, which was also characterized by X-ray crystal structure determination, manganese can easily avail the +3 oxidation state. The relative stabilities of the +2 and +3 oxidation states of manganese were analyzed and it was concluded that the extent of distortion from the perfect octahedral geometry is the main controlling factor in these cases. © 2004 Elsevier B.V. All rights reserved.

Application of the Artificial Intelligence Algorithms for System Analysis of Multi Dimension Physiological Data for Developing Polyparametric Information System of Public Health Diagnostics

The polyparametric intelligence information system for diagnostics human functional state in medicine and public health is developed. The essence of the system consists in polyparametric describing of human functional state with the unified set of physiological parameters and using the polyparametric cognitive model developed as the tool for a system analysis of multitude data and diagnostics of a human functional state. The model is developed on the basis of general principles geometry and symmetry by algorithms of artificial intelligence systems. The architecture of the system is represented. The model allows analyzing traditional signs - absolute values of electrophysiological parameters and new signs generated by the model – relationships of ones. The classification of physiological multidimensional data is made with a transformer of the model. The results are presented to a physician in a form of visual graph – a pattern individual functional state. This graph allows performing clinical syndrome analysis. A level of human functional state is defined in the case of the developed standard (“ideal”) functional state. The complete formalization of results makes it possible to accumulate physiological data and to analyze them by mathematics methods.

Modeling Pulsatility in the Human Cardiovascular System

AMS Subj. Classification: 92C30

A low mortality, high morbidity Reduced Intensity Status Epilepticus (RISE) model of epilepsy and epileptogenesis in the rat

Animal models of acquired epilepsies aim to provide researchers with tools for use in understanding the processes underlying the acquisition, development and establishment of the disorder. Typically, following a systemic or local insult, vulnerable brain regions undergo a process leading to the development, over time, of spontaneous recurrent seizures. Many such models make use of a period of intense seizure activity or status epilepticus, and this may be associated with high mortality and/or global damage to large areas of the brain. These undesirable elements have driven improvements in the design of chronic epilepsy models, for example the lithium-pilocarpine epileptogenesis model. Here, we present an optimised model of chronic epilepsy that reduces mortality to 1% whilst retaining features of high epileptogenicity and development of spontaneous seizures. Using local field potential recordings from hippocampus in vitro as a probe, we show that the model does not result in significant loss of neuronal network function in area CA3 and, instead, subtle alterations in network dynamics appear during a process of epileptogenesis, which eventually leads to a chronic seizure state. The model’s features of very low mortality and high morbidity in the absence of global neuronal damage offer the chance to explore the processes underlying epileptogenesis in detail, in a population of animals not defined by their resistance to seizures, whilst acknowledging and being driven by the 3Rs (Replacement, Refinement and Reduction of animal use in scientific procedures) principles.

Exploring the biological basis for Salmonella persistence in food manufacturing environments

The persistence of Salmonella spp. in low moisture foods is a challenge for the food industry as despite control strategies already in place, notable outbreaks still occur. The aim of this study was to characterise isolates of Salmonella, known to be persistent in the food manufacturing environment, by comparing their microbiological characteristics with a panel of matched clinical and veterinary isolates. The gross morphology of the challenge panel was phenotypically characterised in terms of cellular size, shape and motility. In all the parameters measured, the factory isolates were indistinguishable from the human, clinical and veterinary strains. Further detailed metabolic profiling was undertaken using the biolog Microbial ID system. Multivariate analysis of the metabolic microarray revealed differences in metabolism of the factory isolate of S.Montevideo, based on its upregulated ability to utilise glucose and the sugar alcohol groups. The remainder of the serotype-matched isolates were metabolically indistinguishable. Temperature and humidity are known to influence bacterial survival and through environmental monitoring experimental parameters were defined. The results revealed Salmonella survival on stainless steel was affected by environmental temperatures that may be experienced in a food processing environment; with higher survival rates (D25=35.4) at temperatures at 25°C and lower humidity levels of 15% RH, however a rapid decline in cell count (D10=3.4) with lower temperatures of 10°C and higher humidity of 70% RH. Several resident factories strains survived in higher numbers on stainless steel (D25=29.69) compared to serotype matched clinical and veterinary isolates (D25=22.98). Factory isolates of Salmonella did not show an enhanced growth rate in comparison to serotype matched solates grown in Luria broth, Nutrient broth and M9 minimal media indicating that as an independent factor, growth was unlikely to be a major factor driving Salmonella persistence. Using a live / dead stain coupled with fluorescence microscopy revealed that when no longer culturable, isolates of S.Schwarzengrund entered into a viable nonculturable state. The biofilm forming capacity of the panel was characterised and revealed that all were able to form biofilms. None of the factory isolates showed an enhanced capability to form biofilms in comparison to serotype-matched isolates. In disinfection studies, planktonic cells were more susceptible to disinfectants than cells in biofilm and all the disinfectants tested were successful in reducing bacterial load. Contact time was one of the most important factors for reducing bacterial populations in a biofilm. The genomes of eight strains were sequenced. At the nucleotide and amino acid level the food factory isolates were similar to those of isolates from other environments; no major genomic rearrangements were observed, supporting the conclusions of the phenotypic and metabolic analysis. In conclusion, having investigated a variety of morphological, biochemical and genomic factors, it is unlikely that the persistence of Salmonella in the food manufacturing environment is attributable to a single phenotypic, metabolic or genomic factor. Whilst a combination of microbiological factors may be involved it is also possible that strain persistence in the factory environment is a consequence of failure to apply established hygiene management principles.

Négy jellegzetesség. A magyar fejlődés politikai gazdaságtani megközelítésben. 1. rész = Four characteristic features. Development in Hungary from the aspect of political economy. First Part

A két részből álló cikk a magyarországi reformfolyamat és posztszocialista átalakulás négy olyan jellegzetességét emeli ki, amelyek megszakítás nélkül, a politikai szférában bekövetkezett rendszerváltást követően is, folyamatosan jellemezték az elmúlt harminc év fejlődését: a lakosság anyagi jólétének prioritása, erős paternalista jóléti állam, a reformfolyamat és átmenet fokozatossága és a politikai nyugalom. Az 1995. március 12­én bejelentett stabilizációs program - amennyiben megvalósul - jelenthet elmozdulást ezektől a jellegzetességektől. A cikk politikai gazdaságtani megközelítésben vizsgálja, hogy miért alakult ki ez a négy jellegzetesség, miképpen hatottak azok egymásra, milyen kedvező és kedvezőtlen hatásokat fejtettek ki. Az első rész az 1956­os forradalom hatásából kiindulva politikatörténeti áttekintést ad, majd a mai jólét, biztonság és nyugalom prioritását és a társadalmi adósság felhalmozódását, végül a stabilizációs program gazdasági és politikai hatásait elemzi. / === / The article, consisting of two parts, emphasizes four characteristic features of the Hungarian reform process and the post­socialist transformation, which, uninterruptedly, characterized the development over the last thirty years, even after the systemic change in the political sphere. These were: priority of the material welfare of the population, a strong, paternalistic welfare state, the gradual progress of the reform process and the transition, as well as political calmness. The stabilization programme, announced on March 12,1995, may imply - if it materializes - a shift away from these characteristics. The article investigates, from the aspect of political economy, why the four characteristic features had developed, how they affected each other and what were their advantageous and disadvantageous impacts. Setting out from the impacts of the 1956 revolution, the first part gives an overview of political history and then analyses the priority of today's welfare, security and calm as well as the accumulation of societal debt and, finally, the economic and political impacts of the stabilization programme.

Az állam szerepe a turizmusban (The role of government in tourism)

Az állam szerepe napjainkban átalakulóban van, ami az egyes gazdasági területeken más és más szabályozórendszer alkalmazását igényli a szakterület sajátosságainak és az iparág igényeinek, nemzetközi környezetének megfelelően. A turizmus azon gazdasági területek közé tartozik, amelynek szerepe az elmúlt időszakban dinamikusan növekedett, többek között jelentős bruttó hazai termék-előállító, munkaigényes jellegéből, valamint jelentős beruházást gerjesztő hatásából adódóan. A turizmus mint üzleti tevékenység nem nélkülözheti az állam szerepét. Számos olyan externália társul hozzá, ami államilag koordinált esetben a fejlődést magasabb pályára állítja, és társadalmilag hatékonyabb szinten valósul meg. Napjainkban az állam szerepének újraértelmezése, feladatainak újbóli átgondolása és a megfelelő súlypontok megtalálása elengedhetetlenül szükséges annak érdekében, hogy a turizmus pozitív hatásai hosszú távon érvényesüljenek. _______________ Nowadays the role of the government is changing, which needs the usage of different regulatory systems regarding the requirements of the industry and the international environment. Tourism belongs to the economics fields which importance are growing very rapidly because of its effects such as GDP contribution effect, workforce effect and investment exciting effect. Tourism as a business activity needs the significant role of the government. Tourism is in association with a lot of externalise, therefore can secure the coordination of the state the development and the efficiency at a higher level. Nowadays the rethinking of the task of the government is needed on the field of tourism in the interest of the enforcement of its positive effects.

Molecular Mechanisms Involved in Regulating the Mucoid-to-Nonmucoid Conversion of Pseudomonas aeruginosa Associated with Cystic Fibrosis Patients

Pseudomonas aeruginosa is an opportunistic pathogen that has received attention because of its close association with cystic fibrosis (CF). Chronic pulmonary infection with the mucoid P. aeruginosa is the leading cause of mortality in CF patients. This bacterium has the ability to sense and adapt to the harsh environment in the CF lung by converting from a nonmucoid to a mucoid state. The mucoid phenotype is caused by overproduction of a polysaccharide called alginate. Alginate production is regulated by the algT/U operon containing five genes, algT/U-mucA-mucB-mucC-mucD. Alginate overproduction in CF isolates has been partially attributed to a loss-of-function mutation in mucA that results in the overexpression of algT. This mucoid phenotype is unstable, reverting to the nonmucoid form when the isolates are cultured outside of the CF lung. This study was undertaken to determine the mechanisms involved in the conversion from the mucoid to the nonmucoid form. Thirty-six spontaneous nonmucoid variants of a known mucoid isolate with a mucA mutation were analyzed. Ten of these isolates were complemented in trans by plasmids containing the algT operon and the algT gene. Chromosomal DNA was extracted and the mucA and algT genes were amplified by the polymerase chain reaction. Sequence analysis of the genes showed that these mutants retained the original mucA mutation but acquired secondary mutations in the algT gene.

Forging professional public health nursing in a southern state: Florida's public health nurses, 1889-1934

From 1889 to 1934, Florida's nurses belonging to a new group of professional women ushered in a pioneering phase of public health nursing in Florida. During this era, the nurses' ability to confront health and professional issues varied a great deal but in quiet and forceful ways they tackled cultural and environmental problems to assist people who were ill or help prevent people from becoming ill. This dissertation places the development of professional public health nursing in its social context by uncovering the relationships public health nurses formed with clubwomen, the medical profession, city leaders, midwives, and others. In 1888, there were few graduate nurses in the state, no state board of health and no organized nursing service to respond to Jacksonville's great yellow fever epidemic. By 1934, national and state leaders of public health nursing had built up the profession to become an essential part of the State Board of Health's service to the community. Between these milestones, in the era of white supremacy and Jim Crow, public health nurses combined their professional training with a pioneer spirit of innovation and risk-taking. In the predominately rural state, the public health nurses' resolve to overcome environmental hazards and cultural obstacles stands out as they attempted to reach those who were unserved or underserved by modern medicine.

Guatemala: A Failing State?

 Guatemala is not a failed state and is unlikely to become one in the near future. Although the state currently fails to provide adequate security to its citizens or an appropriate range of effective social programs, it does supply a functioning electoral democracy, sound economic management, and a promising new antipoverty program, My Family Progresses (MIFAPRO).  Guatemala is a weak state. The principal security threats represented by expanding Mexican drug trafficking organizations (DTOs), criminal parallel powers, and urban gangs have overwhelmed the resources of the under-resourced and compromised criminal justice system. The UN-sponsored International Commission against Impunity in Guatemala (CICIG), however, has demonstrated that progress against organized crime is possible.  The principal obstacles to strengthening the Guatemalan state lie in the traditional economic elite’s resistance to taxation and the venal political class’ narrow focus on short-term interests. Guatemala lacks a strong, policyoriented, mass-based political party that could develop a coherent national reform program and mobilize public support around it.  The United States should strengthen the Guatemalan state by expanding the Central America Regional Security Initiative (CARSI) and by strongly supporting CICIG, MIFAPRO, and the Supreme Electoral Tribunal (TSE).

Toward A Better Understanding of the Evolution of Hotel Development: A Discussion of Product-specific Lodging Demand

In his essay - Toward a Better Understanding of the Evolution of Hotel Development: A Discussion of Product-Specific Lodging Demand - by John A. Carnella, Consultant, Laventhol & Horwath, cpas, New York, Carnella initially describes his piece by stating: “The diversified hotel product in the united states lodging market has Resulted in latent room-night demand, or supply-driven demand resulting from the introduction of a lodging product which caters to a specific set of hotel patrons. The subject has become significant as the lodging market has moved toward segmentation with regard to guest room offerings. The author proposes that latent demand is a tangible, measurable phenomenon best understood in light of the history of the guest room product from its infancy to its present state.” The article opens with an ephemeral depiction of hotel development in the United States, both pre’ and post World War II. To put it succinctly, the author wants you to know that the advent of the inter-state highway system changed the complexion of the hotel industry in the U.S. “Two essential ingredients were necessary for the next phase of hotel development in this country. First was the establishment of the magnificently intricate infrastructure which facilitated motor vehicle transportation in and around the then 48 states of the nation,” says Carnella. “The second event…was the introduction of affordable highway travel. Carnella goes on to say that the next – big thing – in hotel evolution was the introduction of affordable air travel. “With the airways filled with potential lodging guests, developers moved next to erect a new genre of hotel, the airport hotel,” Carnella advances his picture. Growth progressed with the arrival of the suburban hotel concept, which wasn’t fueled by developments in transportation, but by changes in people’s living habits, i.e. suburban affiliations as opposed to urban and city population aggregates. The author explores the distinctions between full-service and limited service lodging operations. “The market of interest with consideration to the extended-stay facility is one dominated by corporate office parks,” Carnella proceeds. These evolutional states speak to latent demand, and even further to segmentation of the market. “Latent demand… is a product-generated phenomenon in which the number of potential hotel guests increases as the direct result of the introduction of a new lodging facility,” Carnella brings his unique insight to the table with regard to the specialization process. The demand is already there; just waiting to be tapped. In closing, “…there must be a consideration of the unique attributes of a lodging facility relative to its ability to attract guests to a subject market, just as there must be an examination of the property's ability to draw guests from within the subject market,” Carnella proposes.