Pyrrolo 3,4-g quinoxaline-6,8-dione-based conjugated copolymers for bulk heterojunction solar cells with high photovoltages

A new electron-deficient building block 5,9-di(thiophen-2-yl)-6H-pyrrolo[3,4-g]quinoxaline-6,8(7H)-dione (PQD) was synthesized via functionalizing the 6- and 7-positions of quinoxaline (Qx) with a dicarboxylic imide moiety. Side chain substitution on the PQD unit leads to good solubility which enables very high molecular weight copolymers to be attained. The fusion of two strong electron-withdrawing groups (Qx and dicarboxylic imide) makes the PQD unit a stronger electron-deficient moiety than if the unit had just one electron-withdrawing group, thus enhancing the intramolecular charge transfer between electron-rich and deficient units of the copolymer. Four PQD-based polymers were synthesized which feature deep-lying highest occupied molecular orbital (HOMO) levels and bathochromic absorption spectra when compared to PBDT-Qx and PBDT-TPD analogues. The copolymers incorporated with benzo[1,2-b:4,5-b']dithiophene (BDT) units show that the 1D and 2D structural variations of the side groups on the BDT unit are correlated with the device performance. As a result, the corresponding solar cells (ITO/PEDOT:PSS/polymer: PC71BM/LiF/Al) based on the four copolymers feature very high open-circuit voltages (V-oc) of around 1.0 V. The copolymer PBDT-PQD1 attains the best power conversion efficiency of 4.9%, owing to its relatively high absorption intensity and suitable film morphology. The structure-property correlation demonstrates that the new PQD unit is a promising electron-deficient building block for efficient photovoltaic materials with high V-oc

A linear radiofrequency ion trap for accumulation, bunching, and emittance improvement of radioactive ion beams

An ion beam cooler and buncher has been developed for the manipulation of radioactive ion beams. The gas-filled linear radiofrequency ion trap system is installed at the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. Its purpose is to accumulate the 60-keV continuous ISOLDE ion beam with high efficiency and to convert it into low-energy low-emittance ion pulses. The efficiency was found to exceed 10% in agreement with simulations. A more than 10-fold reduction of the ISOLDE beam emittance can be achieved. The system has been used successfully for first on-line experiments. Its principle, setup and performance will be discussed

'I once wore an angry bird t-shirt and went to read Qur’an': asymmetrical institutional complexity and emerging consumption practices in Pakistan

This article brings together theories of institutional logics and the exploration of the lives of tweens in Pakistan to understand how emerging consumption practices fit within Pakistani children’s daily lives, and how institutional complexity that includes the dominance of religion under Pakistani Islamization is negotiated to separate and maintain the differences between them. We identify resolutions to asymmetrical institutional complexity in the consumption of character T-shirts: spatial–temporal practices, visual practices, symbolic substitution practices and single logic practices. We contribute to an understanding of how consumption happens in an Eastern Muslim culture, and how multiple institutional logics shape the consumption practices of children, by articulating how halal consumption practices, far from being essentialist, or presented as market segmentation, form from negotiations and reflections at the boundaries where Islam and Market logics meet

Precision Measurement of the First Ionization Potential of Nobelium

One of the most important atomic properties governing an element’s chemical behavior is the energy required to remove its least-bound electron, referred to as the first ionization potential. For the heaviest elements, this fundamental quantity is strongly influenced by relativistic effects which lead to unique chemical properties. Laser spectroscopy on an atom-at-a-time scale was developed and applied to probe the optical spectrum of neutral nobelium near the ionization threshold. The first ionization potential of nobelium is determined here with a very high precision from the convergence of measured Rydberg series to be 6.626   21 ± 0.000   05     eV . This work provides a stringent benchmark for state-of-the-art many-body atomic modeling that considers relativistic and quantum electrodynamic effects and paves the way for high-precision measurements of atomic properties of elements only available from heavy-ion accelerator facilities

Rapid detection of carriers with BRCA1 and BRCA2 mutations using high resolution melting analysis

<p>Abstract</p> <p>Background</p> <p>Germline inactivating mutations in <it>BRCA1 </it>and <it>BRCA2 </it>underlie a major proportion of the inherited predisposition to breast and ovarian cancer. These mutations are usually detected by DNA sequencing. Cost-effective and rapid methods to screen for these mutations would enable the extension of mutation testing to a broader population. High resolution melting (HRM) analysis is a rapid screening methodology with very low false negative rates. We therefore evaluated the use of HRM as a mutation scanning tool using, as a proof of principle, the three recurrent BRCA1 and BRCA2 founder mutations in the Ashkenazi Jewish population in addition to other mutations that occur in the same regions.</p> <p>Methods</p> <p>We designed PCR amplicons for HRM scanning of <it>BRCA1 </it>exons 2 and 20 (carrying the founder mutations185delAG and 5382insC respectively) and the part of the <it>BRCA2 </it>exon 11 carrying the 6174delT founder mutation. The analysis was performed on an HRM-enabled real time PCR machine.</p> <p>Results</p> <p>We tested DNA from the peripheral blood of 29 individuals heterozygous for known mutations. All the Ashkenazi founder mutations were readily identified. Other mutations in each region that were also readily detected included the recently identified Greek founder mutation 5331G>A in exon 20 of <it>BRCA1</it>. Each mutation had a reproducible melting profile.</p> <p>Conclusion</p> <p>HRM is a simple and rapid scanning method for known and unknown <it>BRCA1 </it>and <it>BRCA2 </it>germline mutations that can dramatically reduce the amount of sequencing required and reduce the turnaround time for mutation screening and testing. In some cases, such as tracking mutations through pedigrees, sequencing may only be necessary to confirm positive results. This methodology will allow for the economical screening of founder mutations not only in people of Ashkenazi Jewish ancestry but also in other populations with founder mutations such as Central and Eastern Europeans (<it>BRCA1 </it>5382insC) and Greek Europeans (<it>BRCA1 </it>5331G>A).</p

Trace analysis of environmental matrices by large-volume injection and liquid chromatography-mass spectrometry

The time-honored convention of concentrating aqueous samples by solid-phase extraction (SPE) is being challenged by the increasingly widespread use of large-volume injection (LVI) liquid chromatography–mass spectrometry (LC–MS) for the determination of traces of polar organic contaminants in environmental samples. Although different LVI approaches have been proposed over the last 40 years, the simplest and most popular way of performing LVI is known as single-column LVI (SC-LVI), in which a large-volume of an aqueous sample is directly injected into an analytical column. For the purposes of this critical review, LVI is defined as an injected sample volume that is ≥10% of the void volume of the analytical column. Compared with other techniques, SC-LVI is easier to set up, because it requires only small hardware modifications to existing autosamplers and, thus, it will be the main focus of this review. Although not new, SC-LVI is gaining acceptance and the approach is emerging as a technique that will render SPE nearly obsolete for many environmental applications.In this review, we discuss: the history and development of various forms of LVI; the critical factors that must be considered when creating and optimizing SC-LVI methods; and typical applications that demonstrate the range of environmental matrices to which LVI is applicable, for example drinking water, groundwater, and surface water including seawater and wastewater. Furthermore, we indicate direction and areas that must be addressed to fully delineate the limits of SC-LVI

The psychological well-being of Norwegian adolescents exposed in utero to radiation from the Chernobyl accident

<p>Abstract</p> <p>Background</p> <p>On 26 April 1986, the Chernobyl nuclear power plant suffered an accident. Several areas of central Norway were heavily affected by far field radioactive fallout. The present study focuses on the psychological well-being of adolescents who were exposed to this radiation as fetuses.</p> <p>Methods</p> <p>The adolescents (n = 53) and their mothers reported their perceptions of the adolescents' current psychological health as measured by the Youth Self Report and Child Behaviour Checklist.</p> <p>Results</p> <p>In spite of previous reports of subtle cognitive deficits in these exposed adolescents, there were few self-reported problems and fewer problems reported by the mothers. This contrasts with findings of studies of children from the former Soviet Union exposed in utero, in which objective measures are inconsistent, and self-reports, especially by mothers, express concern for adolescents' cognitive functioning and psychological well-being.</p> <p>Conclusion</p> <p>In the current paper, we explore possible explanations for this discrepancy and suggest that protective factors in Norway, in addition to perceived physical and psychological distance from the disaster, made the mothers less vulnerable to Chernobyl-related anxiety, thus preventing a negative effect on the psychological health of both mother and child.</p

Race, colonial history and national identity: Resident Evil 5 as a Japanese game

Resident Evil 5 is a zombie game made by Capcom featuring a White American protagonist and set in Africa. This paper argues that approaching this as a Japanese game reveals aspects of a Japanese racial and colonial social imaginary that are missed if this context of production is ignored. In terms of race, the game presents hybrid racial subjectivities that can be related to Japanese perspectives of Blackness and Whiteness where these terms are two poles of difference and identity through which an essentialised Japanese identity is constructed in what Iwabuchi calls “strategic hybridism” (Iwabuchi, 2002). In terms of colonialism, the game echoes structures of Japanese colonialism through which Japanese colonialism is obliquely memorialised and a “normal” Japanese global subjectivity can be performed