Pattern forming instability induced by light in pure and dye-doped nematic liquid crystals

We study theoretically the instabilities induced by a linearly polarized ordinary light wave incident at a small oblique angle on a thin layer of homeotropically oriented nematic liquid crystal with special emphasis on the dye-doped case. The spatially periodic Hopf bifurcation that occurs as the secondary instability after the stationary Freedericksz transition is analyzed.Comment: 8 pages, 7 figures, LaTeX, accepted to Phys. Rev.

Differential gene-expression patterns in genital fibroblasts of normal males and 46,XY females with androgen insensitivity syndrome: evidence for early programming involving the androgen receptor

BACKGROUND: Androgen insensitivity syndrome (AIS) comprises a range of phenotypes from male infertility to complete feminization. Most individuals with AIS carry germline mutations of the androgen receptor (AR) that interfere with or ablate its function. As genital fibroblasts retain expression of the AR in vitro, we used genital skin fibroblasts from normal males and 46,XY females with complete AIS due to known AR mutations to gain insights into the role of the AR in human genital differentiation. RESULTS: Using DNA microarrays representing 32,968 different genes, we identified 404 transcripts with significant differences in transcription levels between genital skin fibroblasts cultured from normal and AIS-affected individuals. Gene-cluster analyses uncovered coordinated expression of genes involved in key processes of morphogenesis. On the basis of animal studies and human genetic syndromes, several of these genes are known to have specific roles in genital differentiation. Remarkably, genital fibroblasts from both normal and AIS-affected individuals showed no transcriptional response to dihydrotestosterone treatment despite expression of the AR. CONCLUSIONS: The results suggest that in addition to differences in the anatomic origin of the cells, androgen signaling during prenatal development contributes to setting long-lasting, androgen-independent transcriptional programs in genital fibroblasts. Our findings have broad implications in understanding the establishment and the stability of sexual dimorphism in human genital development

Evaluating a Microbial Water Quality Prediction Model for Beach Management Under the Revised EU Bathing Water Directive

The revised Bathing Water Directive (2006/7/EC) requires EU member states to minimise the risk to public health from faecal pollution at bathing waters through improved monitoring and management approaches. While increasingly sophisticated measurement methods (such as microbial source tracking) assist in the management of bathing water resources, the use of deterministic predictive models for this purpose, while having the potential to provide decision making support, remains less common. This study explores an integrated, deterministic catchment-coastal hydro-environmental model as a decision-making tool for beach management which, based on advance predictions of bathing water quality, can inform beach managers on appropriate management actions (to prohibit bathing or advise the public not to bathe) in the event of a poor water quality forecast. The model provides a ‘moving window’ five-day forecast of Escherichia coli levels at a bathing water compliance point off the Irish coast and the accuracy of bathing water management decisions were investigated for model predictions under two scenarios over the period from the 11th August to the 5th September, 2012. Decisions for Scenario 1 were based on model predictions where rainfall forecasts from a meteorological source (www.yr.no) were used to drive the rainfall–runoff processes in the catchment component of the model, and for Scenario 2, were based on predictions that were improved by incorporating real-time rainfall data from a sensor network within the catchment into the forecasted meteorological input data. The accuracy of the model in the decision-making process was assessed using the contingency table and its metrics. The predictive model gave reasonable outputs to support appropriate decision making for public health protection. Scenario 1 provided real-time predictions that, on 77% of instances during the study period where both predicted and E. coli concentrations were available, would correctly inform a beach manager to either take action to mitigate for poor bathing water quality or take no action. However, Scenario 1 also provided data to support a decision to take action (when none was necessary – a type I error) in 4% of instances and to take no action (when action was required – a type II error) in 19% of the instances analysed. Type II errors are critical in terms of public health protection given that for this error, bathers can be exposed to risks from poor bathing water quality. Scenario 2, on the other hand, provided predictions that would support correct management actions for 79% of the instances but would result in type I and type II errors for 4% and 17% of the instances respectively. Comparison of Scenarios 1 and 2 for this study indicate that Scenario 2 gave a marginally better overall performance in terms of supporting correct management decisions, as it provided data that could result in a lower occurrence of the more critical type II errors. Given that the 28 member states of the European Union are required to engage with the public health provisions of the revised Bathing Water Directive, issues of compliance, pertaining particularly to the management of bathing water resources, remain topical. Decision supports for managing bathing waters in the context of the Directive are likely to become the focus of much attention and although, the current study has been validated in bathing waters off the east coast of Ireland, the approach of using a deterministic and integrated catchment-coastal model for such purposes is easily transferable to other bathing water jurisdictions

Solution-processable thienoisoindigo-based molecular donors for organic solar cells with high open-circuit voltage

Two acetylene-bridged Donor–Acceptor–Donor (D-A-D) type small pi-conjugated molecules involving triphenylamine or N-phenylcarbazole as donor blocks (D) and thienoisoindigo as the acceptor unit (A) were synthesized and characterized by UV–Vis absorption and cyclic voltammetry. These donor materials were mixed with [6,6]-phenyl-C61-butyric acid methyl ester to prepare bulk heterojunction solar cells by simple solution processing. Due to their low-lying highest occupied molecular orbital energy levels, high open-circuit voltages up to 0.99 V were measured. The triphenylamine end-capped derivative led to the best power conversion efficiency of ca 2.20%, which ranks among the highest reported value for thienoisoindigo-based materials

Hydro-Environmental Modeling of Sewage and Riverine Discharges into a Coastal Area: Comparison of Depth-averaged and Three-Dimensional Models

This study applies and compares two hydrodynamic and water quality models; a depth-averaged (TELEMAC-2D) and a three-dimensional model (TELEMAC-3D) on their performance in simulating the transport and fate of Escherichia coli (a main microbial bathing water quality indicator) in the coastal waters of Bray, Ireland subjected to sewage discharges and freshwater inflows from the River Dargle. The models first calibrated and validated against hydrodynamic and water quality data, were used to simulate Escherichia coli distribution patterns based on mean spring and mean neap tides for dry and wet weather scenarios. The hydrodynamic calibration yielded a good match between both models (TELEMAC-2D and TELEMAC-3D) and measured velocities. The E. coli model calibrations showed that TELEMAC-2D resulted in a lower value for decay rate (higher T90 value) than TELEMAC-3D in order to match the measured E. coli concentrations. E. coli surface distributions at the time of HW resulted in TELEMAC-2D plumes that were lesser in extent and concentrations than those of TELEMAC-3D due to the fact that depth-averaged hydrodynamics underestimate the surface water velocity resulting in lower concentrations of E. coli at the water surface compared to TELEMAC-3D. The wet weather scenarios of both TELEMAC-2D and TELEMAC-3D exhibited high E. coli concentrations at the water surface that exceed the “Sufficient” limit of the Bathing Water Directive, the latter finding highlights the need for including Ultra Violet disinfection in the treatment process at Shanganagh Sewage Treatment Work

Bathing Water Quality Prediction Using an Integrated Catchment and 3-D Coastal Hydrodynamic Model

Under the new European Union Bathing Water Directive (2006/7/EC) which comes into force in 2014, more stringent bathing water quality standards, defined in terms of Escherichia coli (E.coli) and Intestinal Enterococci (I.E.), will apply in Irish bathing waters. Compliance with these standards is ensured through a structured water quality monitoring programme that is published by Authorities with responsibility for bathing water areas in advance of each bathing season. The directive recognises that elevated levels of faecal coliform bacteria in bathing areas can derive from the overland transport of waste from livestock in the rural fraction of river catchments. On days therefore, that follow significant storm events in coastal agricultural catchments, exceedences of threshold bacteria levels may occur. Given that these exceedences result from ‘natural’ rather than anthropogenic influences, a ‘discounting’ mechanism that allows for a temporary relaxation of these standards is allowed for short-term pollution incidents. In this regard, some high levels of faecal bacteria contamination can be excluded from the water quality record. However, this ‘discounting’ is only permitted if elevated bacterial levels are predicted in advance and mitigation actions to maintain public health protection are taken. This paper presents an integrated catchment (MIKE11) and 3-dimensional coastal (MIKE3) modelling tool for predicting the bathing water quality at Bray, Co. Wicklow. Models were calibrated using flow and water quality data. Adjustment of the M2 and S2 tidal constituents of the MIKE global model has resulted in an improved fit to measured water levels at the five reference tidal gauges. Bottom friction was calibrated to produce good correlations of measured and simulated current speed and direction. Furthermore, results of the water quality transport model has shown that the model has adequately replicated measurements of E.coli and IE

A common founding clone with TP53 and PTEN mutations gives rise to a concurrent germ cell tumor and acute megakaryoblastic leukemia

We report the findings from a patient who presented with a concurrent mediastinal germ cell tumor (GCT) and acute myeloid leukemia (AML). Bone marrow pathology was consistent with a diagnosis of acute megakaryoblastic leukemia (AML M7), and biopsy of an anterior mediastinal mass was consistent with a nonseminomatous GCT. Prior studies have described associations between hematological malignancies, including AML M7 and nonseminomatous GCTs, and it was recently suggested that a common founding clone initiated both cancers. We performed enhanced exome sequencing on the GCT and the AML M7 from our patient to define the clonal relationship between the two cancers. We found that both samples contained somatic mutations in PTEN (C136R missense) and TP53 (R213 frameshift). The mutations in PTEN and TP53 were present at ∼100% variant allele frequency (VAF) in both tumors. In addition, we detected and validated five other shared somatic mutations. The copy-number analysis of the AML exome data revealed an amplification of Chromosome 12p. We also identified a heterozygous germline variant in FANCA (S858R), which is known to be associated with Fanconi anemia but is of uncertain significance here. In summary, our data not only support a common founding clone for these cancers but also suggest that a specific set of distinct genomic alterations (in PTEN and TP53) underlies the rare association between GCT and AML. This association is likely linked to the treatment resistance and extremely poor outcome of these patients. We cannot resolve the clonal evolution of these tumors given limitations of our data

One step synthesis of D-A-D chromophores as active materials for organic solar cells by basic condensation

Donor-Acceptor-Donor conjugated systems are synthesized in good yield by double condensation of aromatic aldehydes of triarylamines with 2,3-diaminomaleonitrile under microwave activation with trifluoroacetic acid as catalyst. The electronic properties of the compounds are investigated and discussed and a first evaluation of their potential as donor material in organic photovoltaic cells is presented

On Metrizability of Invariant Affine Connections

The metrizability problem for a symmetric affine connection on a manifold, invariant with respect to a group of diffeomorphisms G, is considered. We say that the connection is G-metrizable, if it is expressible as the Levi-Civita connection of a G-invariant metric field. In this paper we analyze the G-metrizability equations for the rotation group G = SO(3), acting canonically on three- and four-dimensional Euclidean spaces. We show that the property of the connection to be SO(3)-invariant allows us to find complete explicit description of all solutions of the SO(3)-metrizability equations.Comment: 17 pages, To appear in IJGMMP vol.9 No.1 (2012

Small Molecules for organic photovoltaic

Date du colloque : 05/2013</p