Organic thin-film electronics from vitreous solution-processed rubrene hypereutectics

Electronic devices based on single crystals of organic semiconductors provide powerful means for studying intrinsic charge-transport phenomena and their fundamental electronic limits. However, for technological exploitation, it is imperative not to be confined to the tedious growth and cumbersome manipulation of molecular crystals-which generally show notoriously poor mechanical properties-but to be able to process such materials into robust architectures by simple and efficient means. Here, we advance a general route for facile fabrication of thin-film devices from solution. The key beneficial feature of our process-and the principal difference from existing vapour deposition and solution-processing schemes-is the incorporation of a glass-inducing diluent that enables controlled crystallization from an initial vitreous state of the organic semiconductor, formed in a selected area of the phase diagram of the two constituents. We find that the vitrifying diluent does not adversely affect device performance. Indeed, our environmentally stable, discrete rubrene-based transistors rival amorphous silicon devices, reaching saturated mobilities of up to 0.7 cm2 V-1 s-1, ON-OFF ratios of >or=10(6) and subthreshold slopes as steep as 0.5 V per decade. A nearly temperature-independent device mobility, indicative of a high crystalline quality of our solution-processed, rubrene-based films, corroborates these findings. Inverter and ring-oscillator structures are also demonstrated.     

Evaluation of European energy behavioural change programmes

This article is based on the findings of the BEHAVE Project (Evaluation of Energy Behavioural Change Programmes) which was supported by the European Commission under the EU Intelligent Energy–Europe (IEE) Programme. The project started with a review of behavioural theories and their applicability in the development and evaluation of energy-related behavioural change programmes, progressed to a case study analysis and finished with a publication of guidelines for programme developers and policy makers. This paper concentrates on the results of the case study analysis and the recommendations arising from it. In the case study analysis, information was collected on almost 100 cases aiming at behavioural change in energy use from 11 European countries. More detailed information was collected on 41 cases which were subject to meta-analysis to identify success factors and weak points and to gather information on the current evaluation practices in such programmes. The meta-analysis was carried out in five phases: context (pre-planning), planning, implementation, monitoring and evaluation. Planning and evaluation were recognised as two of the most critical phases. Many of the programmes operated with quite formal plans but were typically not based on scientific theories or evidence. In many cases, there was lack of market segmentation; the goals were not targeted and the programmes tried to offer “everything to everybody”. A multitude of ex-post evaluation methods for programme impacts were reported ranging from participant surveys, testing and comparison with control groups to top–down method evaluating the impact of several programmes focusing on the same target group. Process evaluation (25 cases) was slightly less common than impact evaluation (29 cases). Evaluation of the cost-effectiveness of the programmes was a rarity, most likely due to difficulties in quantitative impact evaluation.     

Explaining the failure of the Dutch innovation system for biomass digestion—A functional analysis

Since the 1970s research on energy conversion technologies, such as biomass digestion, has been carried out in the Netherlands. However, after 30 years biomass digestion has not been implemented on large scale. The aim of this paper is to create insight into the underlying factors of this troublesome trajectory by applying the ‘Functions of Innovation Systems’ framework. This results in clear understanding of the (lack of) activities that took place in the innovation system of biomass digestion and the role of government policy in both inducing and blocking this development. The analysis provides several lessons to take into account when developing policies for the acceleration of the development and diffusion of biomass energy.     

Preovulatory overripeness of the oocyte as a cause of ovarian dysfunction in the human female

A variety of gynaecological phenomena such as menstrual disorders, infertility and premature menopause are associated with ovarian dysfunction. In this paper, a factor is considered that may play a role in the aetiology of ovarian dysfunction. Animal research has shown that preovulatory overripeness of the oocyte may cause various developmental and chromosomal anomalies. Among the developmental anomalies observed in amphibia and fish are a number of gonadal aberrations, often occurring in otherwise normal specimens. This may be the consequence of a degeneration of the 'germinal cytoplasm', cytoplasmic structures located in the vegetative pole region of the oocyte, destined to become part of future primordial germ cells. Indirect evidence suggests that preovulatory overripeness of the oocyte also plays a significant role in human reproductive failure. An increased risk of preovulatory overripeness is expected during periods of endocrine irregularities, such as the first postmenarcheal years, the last premenopausal years, the first months after a pregnancy and, possibly, during certain seasons. If the overripeness-induced gonadal maldevelopment observed in animals also occurs in humans, this may explain variations in reproductive function according to month of birth, as observed in women. It is hypothesized that females conceived during periods of maternal endocrine irregularities face an increased risk of ovarian dysfunction through overripeness-induced gonadal maldevelopment.     

Glucose sensing and signalling properties in Saccharomyces cerevisiae require the presence of at least two members of the glucose transporter family

The kinetics of glucose transport in a number of different mutants of Saccharomyces cerevisiae with multiple deletions in the glucose transporter gene family were determined. The deletions led to differences in maximal rate and affinity for glucose uptake by the cells, dependent on the growth conditions. At the same time, there were changes in glucose repression, as determined by expression of invertase activity. Only in the strain with genes HXT1-4 and SNF3 deleted but carrying HXT6/7 were glucose uptake kinetics and invertase activity independent of the presence or concentration of glucose in the growth medium. Some degree of glucose sensitivity was recovered if the SNF3 or HXT2 gene was present in the multiple-deletion background. It is hypothesized that during growth on glucose, both modulation of the kinetics of glucose uptake and derepression of invertase activity require the presence of more than one active gene of the glucose transporter family.     

Yield-to-BIM: impacts of BIM maturity on project performance

How does organizational experience (maturity) with building information modelling (BIM) impact on the broad implementation of BIM and on company performance? A survey of Dutch architectural, engineering, construction, and operation (AECO) professionals (n?=?890) is used to examine their perceptions of the impact of BIM maturity on firm performance. Survey items included measures of BIM element maturity (i.e., strategy, BIM uses, process, information, infrastructure and personnel), and key performance indicators (time, cost and quality performance). Surprisingly, the maturity of the BIM implementation strategy was the only reliable predictor of time, cost and quality performance. The result suggests that the impact of BIM maturity on project performance may be limited and it cautions against overoptimistic appraisals of BIM. In addition to the contribution to the literature on BIM performance, the paper should be of interest to the practitioner contemplating BIM investments.     

SHORT COMMUNICATION: ACCELERATED PUBLICATION: Dye solar cells without electrolyte or hole‐transport layers: a feasibility study of a concept based on direct regeneration of the dye by metallic conductors

Flat structures consisting of dense dye‐sensitized TiO₂ films with various materials for dye regeneration (TiO₂/dye/regeneration material) are compared. Au and PEDOT:PSS were tested as metal or metal‐like regeneration materials and compared with reference compounds, such as the redox couple I⁻/I in solution and p‐type CuSCN. Under the exclusion of TiO₂ bandgap excitation, the short‐circuit photocurrent densities for the various structures differ by less than ∼30%, suggesting comparable charge separation efficiencies. The good performance of a metallic regeneration material implies, that the frequently assumed requirement of p‐type or ‘hole conducting’ properties for the regeneration material in solid state dye solar cells is questionable. Copyright © 2005 John Wiley & Sons, Ltd.     

Inter-generational ties, financial transfers and home-ownership support

Home-ownership is transmitted between generations. Parental gifts form one of the mechanisms through which the intergenerational transmission of home-ownership takes place. Using the Netherlands Kinship Panel Study, we investigated the influence of parental and children’s resources and other characteristics on financial support from parents to children. A major independent variable was parental home-ownership. As dependent variables, we distinguished between financial support towards buying a home, and financial support in the form of gifts of € 5,000 or more ever received. By making this distinction, we could test whether homeowner parents were particularly likely to help their children become homeowners rather than giving other types of financial help. The results did not indicate such specific gift-giving: parental home-ownership was just as important to other types of monetary support as to home-ownership support. However, the distance to the place where the adult child had grown up was negatively associated with receiving home-ownership support but not with receiving other financial transfers.     

Assessing landscape change and biodiversity values of the Middle Vistula river valley, Poland, using BIO-SAFE

This paper deals with the relation between legally protected biodiversity and riverine ecotopes and with the assessment of biodiversity values of the Middle Vistula river valley (Poland). Furthermore, it describes the effects of landscape change on spatial distribution of ecotope patches and biodiversity values in Kazimierski Landscape Park. Biodiversity values were calculated using BIO-SAFE, a model meant to quantify biodiversity and to value ecotopes based on legally protected species. Dissimilarity indices depict high uniqueness of ecotope types regarding their species assemblages (e.g., river dunes, banks and bars). The actual biodiversity values of the river valley in Kazimierski Landscape Park are high in comparison with floodplains of lowland rivers in Western Europe. GIS analyses of remotely sensed ecotope maps show remarkable differences in number, acreage and patchiness of ecotopes for the years 1953 and 2003. The total number of patches increased by almost 44%. Side channels and floodplain lakes became fragmented. The average and total surface area of bush, forest and arable land increased, but decreased for bare soil, pioneer vegetation and grassland. These landscape changes indicate natural vegetation succession, intensification of agriculture and progressive impacts of river regulation. The Vistula river valley still represents high biodiversity values for higher plants, birds, herpetofauna and fish. However, current landscape changes negatively affect potential values for protected and endangered species. Assessments with BIO-SAFE can help to balance biodiversity conservation, river management and landscape planning.