Deterministic Response Threshold Models of Reproductive Division of Labor Are More Robust Than Probabilistic Models in Artificial Ants.

We implement an agent-based simulation of the response threshold model of reproductive division of labor. Ants in our simulation must perform two tasks in their environment: forage and reproduce. The colony is capable of allocating ant resources to these roles using different division of labor strategies via genetic architectures and plasticity mechanisms. We find that the deterministic allocation strategy of the response threshold model is more robust than the probabilistic allocation strategy. The deterministic allocation strategy is also capable of evolving complex solutions to colony problems like niche construction and recovery from the loss of the breeding caste. In addition, plasticity mechanisms had both positive and negative influence on the emergence of reproductive division of labor. The combination of plasticity mechanisms has an additive and sometimes emergent impact.

Social Learning and Cultural Evolution in Artificial Life.

We describe the questions and discussions raised at the First Workshop on Social Learning and Cultural Evolution held at theArtificial Life Conference 2016 in Cancún, Mexico in July 2016. The purpose of the workshop was to assemble artificial life researchers interested in social learning and cultural evolution into one group so that we could focus on recent work and interesting open questions. Our discussion related to both the mechanisms of social learning and cultural evolution and the consequences and influence of social learning and cultural evolution on living systems. We present the contributions of our workshop presenters and conclude with a discussion of the more important open questions in this area.

Imitation as a mechanism of cultural transmission.

We study the effects of an imitation mechanism on a population of animats capable of individual ontogenetic learning. An urge to imitate others augments a network-based reinforcement learning strategy used in the control system of the animats. We test populations of animats with imitation against populations without for their ability to find, and maintain over generations, successful foraging behavior in an environment containing three necessary resources: food, water, and shelter. We conclude that even simple imitation mechanisms are effective at increasing the frequency of success when measured over time and over populations of animats.

Optimizing aerosol gene delivery and expression in the ovine lung.

We have developed the sheep as a large animal model for optimizing cystic fibrosis gene therapy protocols. We administered aerosolized gene transfer agents (GTAs) to the ovine lung in order to test the delivery, efficacy, and safety of GTAs using a clinically relevant nebulizer. A preliminary study demonstrated GTA distribution and reporter gene expression throughout the lung after aerosol administration of plasmid DNA (pDNA):GL67 and pDNA:PEI complexes. A more comprehensive study examined the dose-response relationship for pDNA:PEI and assessed the influence of adjunct therapeutic agents. We found that the sheep model can differentiate between doses of GTA and that the anticholinergic, glycopyrrolate, enhanced transgene expression. Dose-related toxicity of GTA was reduced by aerosol administration compared to direct instillation. This large animal model will allow us to move toward clinical studies with greater confidence.

The effect of unsaturated fatty acids in benzyl alcohol on the percutaneous permeation of three model penetrants.

The model penetrants butyl paraben (BP), methyl paraben (MP) and caffeine (CF), because of their different octanol/water partition coefficients and postulated routes of permeation through human skin, were selected to assess the enhancing activity of pre-treatment solutions consisting of monounsaturated (oleic (OA) and palmitoleic (PA)) and poly-unsaturated (linoleic (LA)) fatty acids in benzyl alcohol (BA) using Franz diffusion cells and HPLC detection. Prior to assessing the effect of penetrant lipophilicity, MP was chosen to investigate the concentration-dependent effect of fatty acids in pre-treatment solutions. At 5% (w/w) fatty acids in BA, only pre-treatment solutions containing palmitoleic acid (PA) increased the permeation of MP when compared to pre-treatment with BA alone, whereas at higher concentrations (10 and 20%, w/w), all pre-treatment solutions except 10% OA produced a significant increase in MP flux (P<0.05). The general order of fatty acid effectiveness at any concentration was PA>LA>OA. At 20% (w/w) fatty acids in BA, all pre-treatment solutions significantly enhanced the permeation of all three penetrants (P<0.05) and an inverse relationship between penetrant lipophilicity and enhancement effect was observed. The permeation of BP was enhanced to a similar extent by all three fatty acids, whereas PA caused a significantly greater enhancement in the flux of both MP and CF when compared to OA, LA and controls (P<0.05). It was proposed that the synergetic enhancement mechanisms of fatty acids and BA in pre-treatment solutions were augmenting the polar route by way of interactions with both polar and non-polar regions of stratum corneum lipids. Furthermore, the combination of PA and BA appears to be a good candidate as a penetration enhancer for hydrophilic molecules.

Correlation of Epstein-Barr virus DNA in cell-free plasma, functional imaging and clinical course in locally advanced nasopharyngeal cancer: a pilot study.

BACKGROUND: We evaluated the feasibility of using quantitative real-time polymerase chain reaction (PCR) in monitoring Epstein-Barr virus (EBV) DNA concentrations in cell-free plasma of patients with localized nonmetastatic nasopharyngeal carcinoma (NPC) treated with chemoradiation. METHODS: Cell-free plasma EBV DNA was quantified in six patients with locally advanced, nonmetastatic nasopharyngeal cancer (NPC) who underwent chemoradiation therapy (CRT) and correlated with magnetic resonance imaging (MRI), positron emission tomography (PET) scans, and clinical course. RESULTS: The mean concentration of EBV DNA was 24,610 copies/mL, 682 copies/mL, and 64.5 copies/mL in the pretreatment, posttreatment, and last follow-up samples, respectively. Four of the six patients had normal PET scans and reduction of EBV DNA copy numbers to minimal levels after treatment and, despite equivocal posttreatment MRI scans, are clinically free of recurrent disease. Two of the six patients had elevated EBV DNA copy numbers immediately after treatment, but a metastatic workup was clear at the time; both subsequently relapsed with distant metastases 5 and 11 months later. Although the posttreatment PET scans were abnormal in both of these cases, they were not predictive of the subsequent sites of tumor relapse. CONCLUSIONS: To our knowledge, this is the first report on the correlation between EBV DNA levels and PET scan results in patients with NPC. Reductions in EBV DNA levels and normal PET scans after treatment were consistent among patients who had residual abnormality on MRI images. Persistently elevated EBV DNA levels and abnormal PET scans after treatment suggest residual disease. Further evaluations are required to determine the relative contributions of these two novel techniques in predicting residual disease in locally advanced NPC.