Wide energy-window view on the density of states and hole mobility of poly(p-phenylene vinylene)

Using an electrochemically gated transistor, we achieved controlled and reversible doping of poly(p-phenylene vinylene) in a large concentration range. Our data open a wide energy-window view on the density of states (DOS) and show, for the first time, that the core of the DOS function is Gaussian, while the low-energy tail has a more complex structure. The hole mobility increases by more than four orders of magnitude when the electrochemical potential is scanned through the DOS.Comment: 4 pages, 4 figure

Experimental and theoretical investigation of ligand effects on the synthesis of ZnO nanoparticles

ZnO nanoparticles with highly controllable particle sizes(less than 10 nm) were synthesized using organic capping ligands in Zn(Ac)2 ethanolic solution. The molecular structure of the ligands was found to have significant influence on the particle size. The multi-functional molecule tris(hydroxymethyl)-aminomethane (THMA) favoured smaller particle distributions compared with ligands possessing long hydrocarbon chains that are more frequently employed. The adsorption of capping ligands on ZnnOn crystal nuclei (where n = 4 or 18 molecular clusters of(0001) ZnO surfaces) was modelled by ab initio methods at the density functional theory (DFT) level. For the molecules examined, chemisorption proceeded via the formation of Zn...O, Zn...N, or Zn...S chemical bonds between the ligands and active Zn2+ sites on ZnO surfaces. The DFT results indicated that THMA binds more strongly to the ZnO surface than other ligands, suggesting that this molecule is very effective at stabilizing ZnO nanoparticle surfaces. This study, therefore, provides new insight into the correlation between the molecular structure of capping ligands and the morphology of metal oxide nanostructures formed in their presence

Physical and Electrical Performance of Vapor–Solid Grown ZnO Straight Nanowires

Physical and electrical properties of wurtzitic ZnO straight nanowires grown via a vapor–solid mechanism were investigated. Raman spectrum shows four first-order phonon frequencies and a second-order Raman frequency of the ZnO nanowires. Electrical and photoconductive performance of individual ZnO straight nanowire devices was studied. The results indicate that the nanowires reported here are n-type semi-conductors and UV light sensitive, and a desirable candidate for fabricating UV light nanosensors and other applications

Perspectives on care and communication involving incurably ill Turkish and Moroccan patients, relatives and professionals: a systematic literature review

<p>Abstract</p> <p>Background</p> <p>Our aim was to obtain a clearer picture of the relevant care experiences and care perceptions of incurably ill Turkish and Moroccan patients, their relatives and professional care providers, as well as of communication and decision-making patterns at the end of life. The ultimate objective is to improve palliative care for Turkish and Moroccan immigrants in the Netherlands, by taking account of socio-cultural factors in the guidelines for palliative care.</p> <p>Methods</p> <p>A systematic literature review was undertaken. The data sources were seventeen national and international literature databases, four Dutch journals dedicated to palliative care and 37 websites of relevant national and international organizations. All the references found were checked to see whether they met the structured inclusion criteria. Inclusion was limited to publications dealing with primary empirical research on the relationship between socio-cultural factors and the health or care situation of Turkish or Moroccan patients with an oncological or incurable disease. The selection was made by first reading the titles and abstracts and subsequently the full texts. The process of deciding which studies to include was carried out by two reviewers independently. A generic appraisal instrument was applied to assess the methodological quality.</p> <p>Results</p> <p>Fifty-seven studies were found that reported findings for the countries of origin (mainly Turkey) and the immigrant host countries (mainly the Netherlands). The central themes were experiences and perceptions of family care, professional care, end-of-life care and communication. Family care is considered a duty, even when such care becomes a severe burden for the main female family caregiver in particular. Professional hospital care is preferred by many of the patients and relatives because they are looking for a cure and security. End-of-life care is strongly influenced by the continuing hope for recovery. Relatives are often quite influential in end-of-life decisions, such as the decision to withdraw or withhold treatments. The diagnosis, prognosis and end-of-life decisions are seldom discussed with the patient, and communication about pain and mental problems is often limited. Language barriers and the dominance of the family may exacerbate communication problems.</p> <p>Conclusions</p> <p>This review confirms the view that family members of patients with a Turkish or Moroccan background have a central role in care, communication and decision making at the end of life. This, in combination with their continuing hope for the patient’s recovery may inhibit open communication between patients, relatives and professionals as partners in palliative care. This implies that organizations and professionals involved in palliative care should take patients’ socio-cultural characteristics into account and incorporate cultural sensitivity into care standards and care practices<it>.</it></p

Release of engineered nanomaterials from personal care products throughout their life cycle

The impetus for this study was to provide release estimates that can serve to improve predictions of engineered nanomaterial (ENM) exposure for risk assessment. We determined the likely release of ENMs from personal care products (PCPs) through a consumer survey on use and disposal habits, and research on the types and quantities of ENMs in PCPs. Our estimates show that in the US zinc oxide (ZnO), with 1,800-2,100 mt yr-1, and titanium dioxide (TiO2), with 870-1,000 mt yr-1, represent 94 % of ENMs released into the environment or landfills from the use of PCPs. Around 36-43 % of ENMs from PCPs were estimated to end up in landfills, 24-36 % released to soils, 0.7-0.8 % to air, and 28-32 % to water bodies. ENMs in sunscreen represent around 81-82 % of total release, from ZnO and TiO2 as UV blockers, followed by facial moisturizer (7.5 %), foundation (5.7 %), and hair coloring products (3.1 %). Daily care products such as body wash, shampoo, and conditioner had by far the highest per capita and total use, but contributed little to the ENM release estimates as these products generally contain little or no ENMs. However, if ENMs are incorporated into these daily care products, this may substantially increase ENM release. © 2014 Springer Science+Business Media

Het regionale antwoord op de mondialisering (2); Nederlandse boeren kijken in de toekomst

Als boeren steeds grootschaliger voor een wereldmarkt moeten gaan produceren, krijgt Europa dan een gelijkvormig aanzicht? Ziet Engeland er dan hetzelfde uit als laten we zeggen Spanje, Frankrijk, Duitsland of Zweden? En wordt Nederland dan een eenheidsworst? Onderzoekers van Wageninge UR onderzochten deze vraag in twee afzonderlijke onderzoeken. In het ene onderzoek gingen Willem Rienks en Jacqueline van Rijn naar de streek rond Parma en naar de Southeast en ondervroegen betrokkenen op het platteland naar hun antwoorden op de globalisering. Opmerkelijk genoeg reageren boeren in de twee streken heel verschillend op een zelfde mondiale trend. In het andere onderzoek hebben onderzoekers bekeken hoe Nederlandse individuele agrarische ondernemers kunnen reageren op verschillende toekomstscenario¿s. Het blijkt dat boeren ook in verschillende Nederlandse regio¿s heel verschillend op reageren. Beleid zou hier op in kunnen spelen door meer rekening te houden met regionale verschillen in cultuur, en verschillen in fysieke en cultuurhistorische achtergrond van een regio

Depth-relations of recent larger foraminifera in the Gulf of Aqaba-Elat

Intensive research on the recent foraminifera in the Gulf of Aqaba- Elat and their physico-chemical environment is being carried out for the last decade by groups of specialists from the Universities of Jerusalem, Basel, and Copenhagen. The results obtained hitherto indicate that this part of the northern Red Sea may represent a model-area of prime interest for a better understanding of foraminiferal distribution and, therefore, for paleontological interpretations of fossil faunas. The involvement in the study of this model area of the Utrecht University group is based on the latter's participation in the International Geological Correlation Program, Project 73/1/1 "Accuracy in Time". Since many biostratigraphical correlations are based on the evolution of measurable parameters of larger foraminiferal species groups, an investigation of possibly environment-dependent morphological changes in living Foraminifera was urgently needed. A recently advanced theory that proloculus-size might increase at greater water-depth was one such topic. Since the thermo-, halo-, and pycnoclines in the Gulf of Elat are rather insignificant, changes with depth in morphology and distribution of foraminiferal species must be governed by depth-related factors other than temperature, salinity or density. Direct or indirect influence of light penetration and types of substrate are thought to control in the Gulf the depthdistribution of the Soritidae and of the investigated species of Borelis, Amphistegina, Planorbulinella, Operculina, Heterostegina, and Heterocylina. Light may equally influence the intraspecific variation in several of these groups. Major changes seem to take place in the uppermost 80 meters of the depth-profiles. For the LG.C.P. project satisfactory estimates can be made now of the range of variation that mean values of such "evolutionary" features as protoconch diameter and nepionic arrangement may show at one time level, as a consequence of environmental control. The volume summarizes the present-day knowledge on the distribution and morphology of the larger Foraminifera of the Gulf, on their reproduction cycles, symbionts, and their possibly symbiont- and depth-related variability in stable oxygen-isotope ratios