Conjugated Polyions Enable Organic Photovoltaics Processed from Green Solvents

This paper describes the design, synthesis, and optical and electronic properties of two conjugated polymers CPIZ-B and CPIZ-T that incorporate closed-shell cations into their conjugated backbones, balanced by anionic pendant groups. The zwitterionic nature of the polymers renders them soluble in and processable from polar, protic solvents to form semiconducting films that are not doped. These unique properties are confirmed by absorption and electron paramagnetic resonance spectroscopy. The energies of the unoccupied states respond to the tritylium moieties in the conjugated backbone, while the occupied states respond to the electron-donating ability of the uncharged, aromatic units in the backbone. Films cast from 80:20 HCOOH/H2O by volume show good electron mobilities, enabling a photovoltaic effect in proof-of-concept, bilayer solar cells

Stochastic particle packing with specified granulometry and porosity

This work presents a technique for particle size generation and placement in arbitrary closed domains. Its main application is the simulation of granular media described by disks. Particle size generation is based on the statistical analysis of granulometric curves which are used as empirical cumulative distribution functions to sample from mixtures of uniform distributions. The desired porosity is attained by selecting a certain number of particles, and their placement is performed by a stochastic point process. We present an application analyzing different types of sand and clay, where we model the grain size with the gamma, lognormal, Weibull and hyperbolic distributions. The parameters from the resulting best fit are used to generate samples from the theoretical distribution, which are used for filling a finite-size area with non-overlapping disks deployed by a Simple Sequential Inhibition stochastic point process. Such filled areas are relevant as plausible inputs for assessing Discrete Element Method and similar techniques

CRY2 Is Associated with Rapid Cycling in Bipolar Disorder Patients

Bipolar disorder patients often display abnormalities in circadian rhythm, and they are sensitive to irregular diurnal rhythms. CRY2 participates in the core clock that generates circadian rhythms. CRY2 mRNA expression in blood mononuclear cells was recently shown to display a marked diurnal variation and to respond to total sleep deprivation in healthy human volunteers. It was also shown that bipolar patients in a depressive state had lower CRY2 mRNA levels, nonresponsive to total sleep deprivation, compared to healthy controls, and that CRY2 gene variation was associated with winter depression in both Swedish and Finnish cohorts.Four CRY2 SNPs spanning from intron 2 to downstream 3'UTR were analyzed for association to bipolar disorder type 1 (n = 497), bipolar disorder type 2 (n = 60) and bipolar disorder with the feature rapid cycling (n = 155) versus blood donors (n = 1044) in Sweden. Also, the rapid cycling cases were compared with bipolar disorder cases without rapid cycling (n = 422). The haplotype GGAC was underrepresented among rapid cycling cases versus controls and versus bipolar disorder cases without rapid cycling (OR = 0.7, P = 0.006-0.02), whereas overrepresentation among rapid cycling cases was seen for AAAC (OR = 1.3-1.4, P = 0.03-0.04) and AGGA (OR = 1.5, P = 0.05). The risk and protective CRY2 haplotypes and their effect sizes were similar to those recently suggested to be associated with winter depression in Swedes.We propose that the circadian gene CRY2 is associated with rapid cycling in bipolar disorder. This is the first time a clock gene is implicated in rapid cycling, and one of few findings showing a molecular discrimination between rapid cycling and other forms of bipolar disorder

Lack of association between 5HT2A receptor gene haplotype, bipolar disorder and its clinical subtypes in a West European sample

Bipolar affective disorder (BPAD) is a complex psychiatric disorder with a major genetic contribution. Abnormalities in serotonergic function have been implicated in its aetiology. The 5HT2A receptor (5HT2AR) gene is a strong candidate gene for involvement in BPAD, but previous association studies have reported conflicting results. These data are difficult to interpret because most negative results were obtained with small samples. The aim of this study was to test the association between the 5HT2AR gene and BPAD in a large West European sample. We studied the -1438G/A and the His452Tyr polymorphisms, for haplotype analysis to increase both informativity and the likelihood of detecting an association between BPAD and the 5HT2AR gene. We analysed the genotype, allele and haplotype distributions of two 5HT2AR gene variants in a population of 356 BPAD patients, which we compared with 208 healthy controls. We also carried out exploratory analysis in clinical subgroups of patients defined according to personal history of mood disorders, suicidal behaviour, comorbid psychiatric disorders and family history of affective disorders. We found no difference between BPAD patients and controls for allele, genotype and haplotype distributions. Exploratory analysis in subgroups of BPAD patients showed only a marginal difference in haplotype distribution between controls and BPAD patients with antidepressant-induced mania (P = 0.018). This difference was not significant after correction for multiple testing. Our study suggests that the 5HT2AR gene is unlikely to be involved in genetic susceptibility to BPAD but should be further investigated in a pharmacogenetic study

Investigating the dielectric properties and exciton diffusion in C70 derivatives

In recent years, the dielectric constant (εr) of organic semiconductors (OSCs) has been of interest in the organic photovoltaic (OPV) community due to its potential influence on the exciton binding energy. Despite progress in the design of high εr OSCs and the accurate measurement of the εr, the effects of the synthetic strategies on specific (opto)electronic properties of the OSCs remain uncertain. In this contribution, the effects of εr on the optical properties of five new C70 derivatives and [70]PCBM are investigated. Together with [70]PCBM, the derivatives have a range of εr values that depend on the polarity and length of the side chains. The properties of the singlet excitons are investigated in detail with steady-state and time-resolved spectroscopy and the exciton diffusion length is measured. All six derivatives show similar photophysical properties in the neat films. However, large differences in the crystallinity of the fullerene films influence the exciton dynamics in blend films. This work shows that design principles for OSCs with a higher εr can have a very different influence on the performance of traditional BHJ devices and in neat films and it is important to consider the neat film properties when investigating the optoelectronic properties of new materials for OPV

Conjugated Polyions Enable Organic Photovoltaics Processed from Green Solvents

This paper describes the design, synthesis, and optical and electronic properties of two conjugated polymers CPIZ-B and CPIZ-T that incorporate closed-shell cations into their conjugated backbones, balanced by anionic pendant groups. The zwitterionic nature of the polymers renders them soluble in and processable from polar, protic solvents to form semiconducting films that are not doped. These unique properties are confirmed by absorption and electron paramagnetic resonance spectroscopy. The energies of the unoccupied states respond to the tritylium moieties in the conjugated backbone, while the occupied states respond to the electron-donating ability of the uncharged, aromatic units in the backbone. Films cast from 80:20 HCOOH/H2O by volume show good electron mobilities, enabling a photovoltaic effect in proof-of-concept, bilayer solar cells

Rainfall erosivity in Europe

Rainfall is one the main drivers of soil erosion. The erosive force of rainfall is expressed as rainfall erosivity. Rainfall erosivity considers the rainfall amount and intensity, and is most commonly expressed as the R-factor in the USLE model and its revised version, RUSLE. At national and continental levels, the scarce availability of data obliges soil erosion modellers to estimate this factor based on rainfall data with only low temporal resolution (daily, monthly, annual averages). The purpose of this study is to assess rainfall erosivity in Europe in the form of the RUSLE R-factor, based on the best available datasets. Data have been collected from 1541 precipitation stations in all European Union (EU) Member States and Switzerland, with temporal resolutions of 5 to 60min. The R-factor values calculated from precipitation data of different temporal resolutions were normalised to R-factor values with temporal resolutions of 30min using linear regression functions. Precipitation time series ranged from a minimum of 5years to a maximum of 40years. The average time series per precipitation station is around 17.1years, the most datasets including the first decade of the 21st century. Gaussian Process Regression (GPR) has been used to interpolate the R-factor station values to a European rainfall erosivity map at 1km resolution. The covariates used for the R-factor interpolation were climatic data (total precipitation, seasonal precipitation, precipitation of driest/wettest months, average temperature), elevation and latitude/longitude. The mean R-factor for the EU plus Switzerland is 722MJmmha-1h-1yr-1, with the highest values (>1000MJmmha-1h-1yr-1) in the Mediterranean and alpine regions and the lowest (<500MJmmha-1h-1yr-1) in the Nordic countries. The erosivity density (erosivity normalised to annual precipitation amounts) was also the highest in Mediterranean regions which implies high risk for erosive events and floods