6,768 research outputs found
Attainment of hydrogel-thickened nanoemulsions with tea tree oil (Melaleuca alternifolia) and retinyl palmitate
We propose the development of hydrogel-thickned nanoemulsions (HTNs) with tea tree essential oil (Melaleuca alternifolia) and vitamin A palmitate (retinyl palmitate). Nanoemulsions and HTNs were produced by the use of phase inversion method, employing non-ionic surfactants. As surfactant phase were used sorbitan esters and hydrogenated/ethoxylated castor oil. HTNs with drops size ranging between 86 to 96 nm were obtained, depending on the polymer used, with increased viscosity. Rheological profile of developed HTNs was determined, showing the influence of the kind of polymer used, here all presented pseudo-plastic behaviour, with different viscosity measurement.Key words: Nanoemulsion, hydrogel-thickened nanoemulsion, essential oil, phase inversion, vitamin A, retinyl palmitate, tea tree oil
Conformational Dynamics and Responsiveness of Weak and Strong Polyelectrolyte Brushes: Atomistic Simulations of Poly(dimethyl aminoethyl methacrylate) and Poly(2-(methacryloyloxy)ethyl trimethylammonium chloride).
The complex solution behavior of polymer brushes is key to control their properties, including for biomedical applications and catalysis. The swelling behavior of poly(dimethyl aminoethyl methacrylate) (PDMAEMA) and poly(2-(methacryloyloxy)ethyl trimethylammonium chloride) (PMETAC) in response to changes in pH, solvent, and salt types has been investigated using atomistic molecular dynamics simulations. PDMAEMA and PMETAC have been selected as canonical models for weak and strong polyelectrolytes whose complex conformational behavior is particularly challenging for the development and validation of atomistic models. The GROMOS-derived atomic parameters reproduce the experimental swelling coefficients obtained from ellipsometry measurements for brushes of 5-15 nm thickness. The present atomistic models capture the protonated morphology of PDMAEMA, the swollen and collapsed conformations of PDMAEMA and PMETAC in good and bad solvents, and the salt-selective response of PMETAC. The modular nature of the molecular models allows for the simple extension of atomic parameters to a variety of polymers or copolymers
Synergy between intention recognition and commitments in cooperation dilemmas
Commitments have been shown to promote cooperation if, on the one hand, they can be sufficiently enforced, and on the other hand, the cost of arranging them is justified with respect to the benefits of cooperation. When either of these constraints is not met it leads to the prevalence of commitment free-riders, such as those who commit only when someone else pays to arrange the commitments. Here, we show how intention recognition may circumvent such weakness of costly commitments. We describe an evolutionary model, in the context of the one-shot Prisoner's Dilemma, showing that if players first predict the intentions of their co-player and propose a commitment only when they are not confident enough about their prediction, the chances of reaching mutual cooperation are largely enhanced. We find that an advantageous synergy between intention recognition and costly commitments depends strongly on the confidence and accuracy of intention recognition. In general, we observe an intermediate level of confidence threshold leading to the highest evolutionary advantage, showing that neither unconditional use of commitment nor intention recognition can perform optimally. Rather, our results show that arranging commitments is not always desirable, but that they may be also unavoidable depending on the strength of the dilemma.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
A hybrid intelligent agent for notification of users distracted by mobile phones in an urban environment
Mobile devices are now ubiquitous in daily life and the number of activities that can be performed using them
is continually growing. This implies increased attention being placed on the device and diverted away from
events taking place in the surrounding environment. The impact of using a smartphone on pedestrians in the
vicinity of urban traffic has been investigated in a multimodal, fully immersive, virtual reality environment.
Based on experimental data collected, an agent to improve the attention of users in such situations has been
developed. The proposed agent uses explicit, contextual data from experimental conditions to feed a statistical
learning model. The agent’s decision process is aimed at notifying users when they become unaware of critical
events in their surroundings
Acquired trichostasis in postoperative site: a case report
This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
Comparative genomic analysis of a multiple antimicrobial resistant enterotoxigenic E. coli O157 lineage from Australian pigs
© 2015 Wyrsch et al. Background: Enterotoxigenic Escherichia coli (ETEC) are a major economic threat to pig production globally, with serogroups O8, O9, O45, O101, O138, O139, O141, O149 and O157 implicated as the leading diarrhoeal pathogens affecting pigs below four weeks of age. A multiple antimicrobial resistant ETEC O157 (O157 SvETEC) representative of O157 isolates from a pig farm in New South Wales, Australia that experienced repeated bouts of pre- and post-weaning diarrhoea resulting in multiple fatalities was characterized here. Enterohaemorrhagic E. coli (EHEC) O157:H7 cause both sporadic and widespread outbreaks of foodborne disease, predominantly have a ruminant origin and belong to the ST11 clonal complex. Here, for the first time, we conducted comparative genomic analyses of two epidemiologically-unrelated porcine, disease-causing ETEC O157; E. coli O157 SvETEC and E. coli O157:K88 734/3, and examined their phylogenetic relationship with EHEC O157:H7. Results: O157 SvETEC and O157:K88 734/3 belong to a novel sequence type (ST4245) that comprises part of the ST23 complex and are genetically distinct from EHEC O157. Comparative phylogenetic analysis using PhyloSift shows that E. coli O157 SvETEC and E. coli O157:K88 734/3 group into a single clade and are most similar to the extraintestinal avian pathogenic Escherichia coli (APEC) isolate O78 that clusters within the ST23 complex. Genome content was highly similar between E. coli O157 SvETEC, O157:K88 734/3 and APEC O78, with variability predominantly limited to laterally acquired elements, including prophages, plasmids and antimicrobial resistance gene loci. Putative ETEC virulence factors, including the toxins STb and LT and the K88 (F4) adhesin, were conserved between O157 SvETEC and O157:K88 734/3. The O157 SvETEC isolate also encoded the heat stable enterotoxin STa and a second allele of STb, whilst a prophage within O157:K88 734/3 encoded the serum survival gene bor. Both isolates harbor a large repertoire of antibiotic resistance genes but their association with mobile elements remains undetermined. Conclusions: We present an analysis of the first draft genome sequences of two epidemiologically-unrelated, pathogenic ETEC O157. E. coli O157 SvETEC and E. coli O157:K88 734/3 belong to the ST23 complex and are phylogenetically distinct to EHEC O157 lineages that reside within the ST11 complex
Counterfactual thinking in cooperation dynamics
Counterfactual Thinking is a human cognitive ability studied in a wide
variety of domains. It captures the process of reasoning about a past event
that did not occur, namely what would have happened had this event occurred,
or, otherwise, to reason about an event that did occur but what would ensue had
it not. Given the wide cognitive empowerment of counterfactual reasoning in the
human individual, the question arises of how the presence of individuals with
this capability may improve cooperation in populations of self-regarding
individuals. Here we propose a mathematical model, grounded on Evolutionary
Game Theory, to examine the population dynamics emerging from the interplay
between counterfactual thinking and social learning (i.e., individuals that
learn from the actions and success of others) whenever the individuals in the
population face a collective dilemma. Our results suggest that counterfactual
reasoning fosters coordination in collective action problems occurring in large
populations, and has a limited impact on cooperation dilemmas in which
coordination is not required. Moreover, we show that a small prevalence of
individuals resorting to counterfactual thinking is enough to nudge an entire
population towards highly cooperative standards.Comment: 18 page
Microsphere Solid-State Biolasers
Microsphere solid-state biolasers made of biomaterials-bovine serum albumin,
pectin and cellulose are demonstrated. The fabrication is simple, based on
emulsion, and with green processing. A lasing threshold of 1 microJ/mm2 and Q
factor of 3000 are measured. The lasers are biocompatible, do not interfere
with cell growth and division
Cost-effective external interference for promoting the evolution of cooperation.
The problem of promoting the evolution of cooperative behaviour within populations of self-regarding individuals has been intensively investigated across diverse fields of behavioural, social and computational sciences. In most studies, cooperation is assumed to emerge from the combined actions of participating individuals within the populations, without taking into account the possibility of external interference and how it can be performed in a cost-efficient way. Here, we bridge this gap by studying a cost-efficient interference model based on evolutionary game theory, where an exogenous decision-maker aims to ensure high levels of cooperation from a population of individuals playing the one-shot Prisoner's Dilemma, at a minimal cost. We derive analytical conditions for which an interference scheme or strategy can guarantee a given level of cooperation while at the same time minimising the total cost of investment (for rewarding cooperative behaviours), and show that the results are highly sensitive to the intensity of selection by interference. Interestingly, we show that a simple class of interference that makes investment decisions based on the population composition can lead to significantly more cost-efficient outcomes than standard institutional incentive strategies, especially in the case of weak selection.</p
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