Accuracy of defect distributions measured by bias dependent admittance spectroscopy on thin film solar cells

Thin film solar cells have achieved efficiencies up to 20%. Despite these excellent results, the understanding of the underlying mechanisms and the influence of defects on their performance is still incomplete. In thin film solar cells often defect level distributions are present rather than discrete defects. These distributions can be calculated from admittance measurements, however several assumptions are needed which hinder an exact defect density determination. By performing the measurements under different bias voltage conditions the accuracy of the method can be improved and assessed. This is illustrated with measurements on a flexible thin film Cu(In,Ga)Se2- based (CIGS) solar cell

Modelling thin film solar cells with graded band gap

This paper discusses how graded absorber structures in CIGS-based solar cell can be studied using the numerical simulation tool SCAPS. A model will be built for an AVANCIS solar cell with double grading which is produced with the laboratory line process. We will first discuss how literature and measurement data should be used to start the buildup of the model and afterwards give an illustration how the model then still has to be optimized. We will draw special attention to the consequences of a graded structure on the model. Moreover, we will show how one can discern the real grading benefit by comparison with a uniform reference model

Psalm 22 LXX in Origen’s commentary on the Song of Songs

This article examines three distinct ways of reading Psalm 23(LXX 22), first in the Targum, then in the liturgy of early Christian initiation, and finally in Origen’s commentary on the Song of Songs. The Targum focuses on God’s protective presence in Israel’s history and looks forward to the salvation to come. Reading the psalm in the context of Christian initiation draws out the contextual possibilities of the text. In his interpretation of the Song of Songs, Origen seeks elements of spiritual progress after the stage of initiation. The “inebriating cup” points to a strongly affective dimension of this process

Philo’s De Decalogo: educating to respect the socially disadvantaged

Respect and care for the disadvantaged are firmly embedded in Philo’s interpretation of the Decalogue. In order to understand Philo’s teaching on this point within its proper perspective, this study highlights the following aspects of his interpretation of the Decalogue. The Ten Commandments are intended as a means of education, healing and transformation of people and their communities; they guide people to live in harmony with nature, reason and one another; in practice, this means to learn how to turn away from foolish pride and to live in gentleness, fellowship, simplicity, and equality. Such education will render people sensitive to the needs of those affected by bad fortune and inspire them to reach out to them

Allegorising: The Relevance of an Old Method of Interpretation

The question about what texts mean for us in the present as distinct from the question what they originally meant has again come into the focus of attention. This broadening of the focus is very important for understanding religious texts as texts about God’s transforming relationship to people. This article considers the Biblical interpretation of the Church Fathers, and particularly their use of allegory, as this may inspire us to develop ways of interacting with the Biblical texts as religious texts meant to speak to our times

Quine’s ideological debacle

In two papers in the mid-seventies, Quine has discussed an ontological deba-cle, the reduction of ontology to an ontology of pure sets only. This debacle, which weakened Quine’s interest in ontology, is the natural outcome of on-tological relativity, or, more precisely, the proxy-function argument. It is ex-plained how Quine unavoidably came to this conclusion. Moreover, it is ar-gued that the result is even more damaging for Quine’s philosophy than has hitherto been assumed. It is shown that in addition to an ontological debacle, there is an ideological debacle, reducing the ideology (lexicon) of science to the ideology of set theory. The ideological debacle results from applying ex-tensional substitution of predicates within a scientific theory that is reinter-preted by means of proxy-functions to a theory with a set-theoretic ontology. Though Quine has recognized the possibility of an ideological debacle, his rebuttal is unconvincing. As a result, his tenet of extensionalism is under heavy pressure

Exploring the neuroblastoma DNA methylome: from biology to biomarker

Neuroblastoma (NB), a childhood tumor arising from immature sympathetic nervous system cells, is a heterogeneous disease with prognosis ranging from excellent long-term survival to high-risk with fatal outcome. In order to determine the most appropriate treatment modality, patients are stratified into risk groups at the time of diagnosis, based on combinations of clinical and biological parameters, namely age of the patient, tumor stage, histology, grade of differentiation, MYCN oncogene amplification, chromosome 11q aberration and DNA ploidy. However, use of this risk classification system has shown that accurate assessment of NB prognosis remains difficult and that additional prognostic markers are warranted. Therefore, we aimed to identify prognostic tumor DNA methylation biomarkers for NB. To find new biomarkers, we profiled the primary tumor DNA methylome using methyl-CpG-binding domain (MBD) sequencing, i.e. massively parallel sequencing of methylation-enriched DNA fractions, captured using the high affinity of MBD to bind methylated cytosines. As proof of principle, we applied this technology to 8 NB cell lines, and in combination with mRNA expression studies, this led to a first selection of 43 candidate biomarkers. Next, methylation-specific PCR (MSP) assays were designed, to allow candidate-specific methylation analysis in a primary tumor cohort of 89 samples. As such, we identified new prognostic DNA methylation biomarkers, and delineated the technological aspects and data analysis pipeline to set up a more extended biomarker study. In this follow-up study, the DNA methylome of 102 primary tumors, selected for risk classification and survival, was characterized by MBD sequencing. Differential methylation analyses between the prognostic patient groups put forward 78 top-ranking biomarker candidates, which were subsequently tested on two independent cohorts of 132 and 177 samples, adopting the high-throughput MSP pipeline of our pilot study. Multiple individual MSP assays were prognostically validated and through the implementation of a newly developed statistical framework, a robust 58-marker methylation signature predicting overall and event-free survival was established. This study represents the largest DNA methylation (biomarker) study in NB so far. The MBD sequencing data were shared with the research community through the format of a data descriptor. As such, these data are fully available to others, ensuring its reusability for other research purposes. To illustrate how these data can be applied to gain new insights into the NB pathology, we characterized the DNA methylome of stage 4S NB, a special type of NB found in infants with widespread metastases at diagnosis that paradoxically is associated with an excellent outcome due to its remarkable capacity to undergo spontaneous regression. More specifically, we compared promoter methylation levels between stage 4S, stage 1/2 (localized disease with favorable prognosis) and stage 4 (metastatic disease with dismal prognosis) tumors, and showed that specific chromosomal locations are enriched in stage 4S differentially methylated promoters and that specific subtelomeric promoters are hypermethylated in stage 4S. Furthermore, genes involved in important oncogenic pathways, in neural crest development and differentiation, and in epigenetic processes are differentially methylated and expressed in stage 4S. In conclusion, by exploring the DNA methylome of NB, we have not only demonstrated that DNA methylation patterns are intimately related to NB biology, but also found additional clinically relevant prognostic biomarkers