Linköping University

About: Linköping University is a education organization based out in Linköping, Sweden. It is known for research contribution in the topics: Population & Health care. The organization has 15671 authors who have published 50013 publications receiving 1542189 citations.

High Performance All-Polymer Solar Cells by Synergistic Effects of Fine-Tuned Crystallinity and Solvent Annealing

Abstract: Growing interests have been devoted to the design of polymer acceptors as potential replacement for fullerene derivatives for high-performance all polymer solar cells (all-PSCs). One key factor that is limiting the efficiency of all-PSCs is the low fill factor (FF) (normally <0.65), which is strongly correlated with the mobility and film morphology of polymer:polymer blends. In this work, we find a facile method to modulate the crystallinity of the well-known naphthalene diimide (NDI) based polymer N2200, by replacing a certain amount of bithiophene (2T) units in the N2200 backbone by single thiophene (T) units and synthesizing a series of random polymers PNDI-Tx, where x is the percentage of the single T. The acceptor PNDI-T10 is properly miscible with the low band gap donor polymer PTB7-Th, and the nanostructured blend promotes efficient exciton dissociation and charge transport. Solvent annealing (SA) enables higher hole and electron mobilities, and further suppresses the bimolecular recombination. As expected, the PTB7-Th:PNDI-T10 solar cells attain a high PCE of 7.6%, which is a 2-fold increase compared to that of PTB7-Th:N2200 solar cells. The FF of 0.71 reaches the highest value among all-PSCs to date. Our work demonstrates a rational design for fine-tuned crystallinity of polymer acceptors, and reveals the high potential of all-PSCs through structure and morphology engineering of semicrystalline polymer:polymer blends.

Aetiology and risk factors related to traumatic dental injuries--a review of the literature

Abstract: BACKGROUND/AIM: During the past 30 years, the number of etiologies of traumatic dental injuries (TDIs) has increased dramatically in the literature and now includes a broad spectrum of variables, including oral and environmental factors and human behaviour. The aim of this study is to present an international review of well-known as well as less well-known unintentional and intentional causes of TDIs. Moreover, some models that are useful in investigating contact sport injuries are presented. MATERIALS AND METHODS: The databases of Medline, Cochrane, Social Citation Index, Science Citation Index and CINAHL from 1995 to the present were used. RESULT: Oral factors (increased overjet with protrusion), environmental determinants (material deprivation) and human behaviour (risk-taking children, children being bullied, emotionally stressful conditions, obesity and attention-deficit hyperactivity disorder) were found to increase the risk for TDIs. Other factors increasing the risk for TDIs are presence of illness, learning difficulties, physical limitations and inappropriate use of teeth. A new cause of TDIs that is of particular interest is oral piercing. In traffic facial injury was similar in unrestrained occupants (no seat belts) and occupants restrained only with an air bag. Amateur athletes have been found to suffer from TDIs more often than professional athletes. Falls and collisions mask intentional TDIs, such as physical abuse, assaults and torture. Violence has increased in severity during the past few decades and its role has been underestimated when looking at intentional vs unintentional TDIs. There are useful models to prevent TDIs from occurring in sports. WHO Healthy Cities and WHO Health Promoting Schools Programmes offer a broad solution for dental trauma as a public health problem. CONCLUSION: The number of known causes of TDIs has grown to alarming levels, probably because of increased interest of the causes and the underlying complexity of a TDI. Accepted oral, environmental and human aetiological factors must therefore be included in the registration of TDIs. Language: en

Ecosystem subsidies: terrestrial support of aquatic food webs from 13c addition to contrasting lakes

Abstract: Whole-lake additions of dissolved inorganic C-13 were used to measure allochthony (the terrestrial contribution of organic carbon to aquatic consumers) in two unproductive lakes (Paul and Peter Lakes in 2001), a nutrient-enriched lake (Peter Lake in 2002), and a dystrophic lake (Tuesday Lake in 2002). Three kinds of dynamic models were used to estimate allochthony: a process-rich, dual-isotope flow model based on mass balances of two carbon isotopes in 12 carbon pools; simple univariate time-series models driven by observed time courses of delta(13)CO(2); and multivariate autoregression models that combined information from time series of delta(13)C in several interacting carbon pools. All three models gave similar estimates of allochthony. In the three experiments without nutrient enrichment, flows of terrestrial carbon to dissolved and particulate organic carbon, zooplankton, Chaoborus, and fishes were substantial. For example, terrestrial sources accounted for more than half the carbon flow to juvenile and adult largemouth bass, pumpkinseed sunfish, golden shiners, brook sticklebacks, and fathead minnows in the unenriched experiments. Allochthony was highest in the dystrophic lake and lowest in the nutrient-enriched lake. Nutrient enrichment of Peter Lake decreased allochthony of zooplankton from 0.34-0.48 to 0-0.12, and of fishes from 0.51-0.80 to 0.25-0.55. These experiments show that lake ecosystem carbon cycles, including carbon flows to consumers, are heavily subsidized by organic carbon from the surrounding landscape.