Self-Assembly of Patchy Particles into Polymer Chains: A Parameter-Free Comparison between Wertheim Theory and Monte Carlo Simulation

We numerically study a simple fluid composed of particles having a hard-core repulsion, complemented by two short-ranged attractive (sticky) spots at the particle poles, which provides a simple model for equilibrium polymerization of linear chains. The simplicity of the model allows for a close comparison, with no fitting parameters, between simulations and theoretical predictions based on the Wertheim perturbation theory, a unique framework for the analytic prediction of the properties of self-assembling particle systems in terms of molecular parameter and liquid state correlation functions. This theory has not been subjected to stringent tests against simulation data for ordering across the polymerization transition. We numerically determine many of the thermodynamic properties governing this basic form of self-assembly (energy per particle, order parameter or average fraction of particles in the associated state, average chain length, chain length distribution, average end-to-end distance of the chains, and the static structure factor) and find that predictions of the Wertheim theory accord remarkably well with the simulation results

Universal Statistical Behavior of Neural Spike Trains

We construct a model that predicts the statistical properties of spike trains generated by a sensory neuron. The model describes the combined effects of the neuron's intrinsic properties, the noise in the surrounding, and the external driving stimulus. We show that the spike trains exhibit universal statistical behavior over short times, modulated by a strongly stimulus-dependent behavior over long times. These predictions are confirmed in experiments on H1, a motion-sensitive neuron in the fly visual system.Comment: 7 pages, 4 figure

Rapid, sensitive, type specific PCR detection of the E7 region of human papillomavirus type 16 and 18 from paraffin embedded sections of cervical carcinoma

Human papillomavirus (HPV) infection, and in particularly infection with HPVs 16 and 18, is a central carcinogenic factor in the uterine cervix. We established and optimized a PCR assay for the detection and discrimination of HPV types 16 and 18 in archival formaldehyde fixed and paraffin embedded (FFPE) sections of cervical cancer

GIS-BASED SUITABILITY MODELLING FOR THE EUROPEAN OYSTER WITHIN THE GERMAN EXCLUSIVE ZONE OF THE NORTH SEA

Oyster reefs are ecologically important habitats that have been suffering from anthropogenic stressors and severe damages over the past century. More than 85 % of the world's oyster reefs have already been destroyed, have disappeared or their existence is under severe and immediate threat. Due to their central ecological importance for benthic and bentho-pelagic systems and processes associated with important ecosystem functions and services, the restoration of oyster reefs is a focus of marine conservation measures worldwide. In the context of marine spatial planning and complex land use conflicts, and aimed at maximising the ecological success of such restoration measures, GIS-based habitat suitability analyses for oyster reintroduction have been conducted. The aim of the present study was to model and identify suitable habitats for the European oyster within the marine protected areas of Borkum Reefground and Sylt Outer Reef in the German Bight for which the restoration of biogenic reefs, namely native oyster reefs is a designated measure. For this purpose, a multi-criteria decision analysis was designed and applied. Based on geodata of the ecological habitat preferences of the European oyster and relevant logistic factors (contraindicated uses), suitable large- scale areas were successfully identified for which a reintroduction of the formerly native species is favourable. Both suitable and unsuitable habitats could therefore successfully be identified for both nature reserves. Due to the large impact of different standardisation procedures for the suitability variables applied, corresponding results may differ quite severely. Hence four different classifications were applied on the most important factor, ground fisheries accounting for a relative weighting of ca. 30% in the derived suitability formula. The results undermine the necessity of well-grounded scientific and practical reasons to decide on a suitable classification procedure in the multicriteria analysis

Differential Methylation of the HPV 16 Upstream Regulatory Region during Epithelial Differentiation and Neoplastic Transformation

High risk human papillomaviruses are squamous epitheliotropic viruses that may cause cervical and other cancers. HPV replication depends on squamous epithelial differentiation. Transformation of HPV-infected cells goes along with substantial alteration of the viral gene expression profile and preferentially occurs at transformation zones usually at the uterine cervix. Methylation of the viral genome may affect regulatory features that control transcription and replication of the viral genome. Therefore, we analyzed the methylation pattern of the HPV16 upstream regulatory region (URR) during squamous epithelial differentiation and neoplastic transformation and analyzed how shifts in the HPV URR methylome may affect viral gene expression and replication. HPV 16 positive biopsy sections encompassing all stages of an HPV infection (latent, permissive and transforming) were micro-dissected and DNA was isolated from cell fractions representing the basal, intermediate, and superficial cell layers, each, as well as from transformed p16INK4a-positive cells. We observed fundamental changes in the methylation profile of transcription factor binding sites in the HPV16 upstream regulatory region linked to the squamous epithelial differentiation stage. Squamous epithelial transformation indicated by p16INK4a overexpression was associated with methylation of the distal E2 binding site 1 leading to hyper-activation of the HPV 16 URR. Adjacent normal but HPV 16-infected epithelial areas retained hyper-methylated HPV DNA suggesting that these viral genomes were inactivated. These data suggest that distinct shifts of the HPV 16 methylome are linked to differentiation dependent transcription and replication control and may trigger neoplastic transformation

TOPical Imiquimod treatment of high-grade Cervical intraepithelial neoplasia (TOPIC trial): Study protocol for a randomized controlled trial

Background: Cervical intraepithelial neoplasia (CIN) is the premalignant condition of cervical cancer. Whereas not all high grade CIN lesions progress to cervical cancer, the natural history and risk of progression of individual lesions remain unpredictable. Therefore, high-grade CIN is currently treated by surgical excision: large loop excision of the transformation zone (LLETZ). This procedure has potential complications, such as acute haemorrhage, prolonged bleeding, infection and preterm birth in subsequent pregnancies. These complications could be prevented by development of a non-invasive treatment modality, such as topical imiquimod treatment. The primary study objective is to investigate the efficacy of topical imiquimod 5 % cream for the treatment of high-grade CIN and to develop a biomarker profile to predict clinical response to imiquimod treatment. Secondary study objectives are to assess treatment side-effects, disease recurrence and quality of life during and after different treatment modalities. Methods/design: The study design is a randomized controlled trial. One hundred fort