Wouter Maes

Towards domestication of Jatropha curcas

Jatropha curcas L. attracts a lot of interest as a biofuel crop, triggering large investments and rapid expansion of cultivation areas, and yet, it should still be considered as a (semi-)wild, undomesticated plant. To use the full potential of Jatropha and to support further expansion and systematic selection, breeding and domestication are a prerequisite. This review reveals and identifies gaps in knowledge that still impede domestication of Jatropha. Prebreeding knowledge is limited. In particular, the regeneration ecology and the degree of genetic diversity among and within natural populations in and outside the center of origin are poorly studied. There is only a limited understanding of the Jatropha breeding system and the effect of inbreeding and outbreeding. This review presents all currently available and relevant information on the species distribution, site requirements, regeneration ecology, genetic diversity, advances in selection, development of varieties and hybridization. It also describes possible routes to a better Jatropha germplasm, gives recommendations for tackling current problems and provides guidance for future research. We also discuss the participatory domestication strategy of Jatropha integration in agroforestry.

Global greenhouse gas implications of land conversion to biofuel crop cultivation in arid and semi-arid lands: lessons learned from Jatropha

Biofuels are considered as a climate-friendly energy alternative. However, their environmental sustainability is increasingly debated because of land competition with food production, negative carbon balances and impacts on biodiversity. Arid and semi-arid lands have been proposed as a more sustainable alternative without such impacts. In that context this paper evaluates the carbon balance of potential land conversion to Jatropha cultivation, biofuel production and use in arid and semi-arid areas. This evaluation includes the calculation of carbon debt created by these land conversions and calculation of the minimum Jatropha yield necessary to repay the respective carbon debts within 15 or 30 years. The carbon debts caused by conversion of arid and semi-arid lands to Jatropha vary largely as a function of the biomass carbon stocks of the land use types in these regions. Based on global ecosystem carbon mapping, cultivated lands and marginal areas (sparse shrubs, herbaceous and bare areas) show to have similar biomass carbon stocks (on average 4e 8tCh a � 1 ) and together cover a total of 1.79 billion ha.

Use of inadequate data and methodological errors lead to an overestimation of the water footprint of Jatropha curcas

In their recent article, Gerbens-Leenes et al. (1) calculated the water footprint (WF), the amount of water required to produce 1 GJ of energy, of several bioenergy crops. The water footprint of Jatropha curcas was remarkably high (8.6 times higher than the WF of sugar beet, the most water-efficient crop), which may have serious implications for its future management.

Salicylate determination in human plasma by ISEs incorporating Mn(III)-porphyrine and Zn(II)-dipyrromethene

Abstract A new liquid‐membrane electrode incorporating Mn(III)‐porphyrin and Zn(II)‐dipyrromethene has been studied for direct salicylic acid determination in human plasma. The membranes were doped additionally with lipophilic salts of tetrakis(p‐chlorophenyl)borate (KTpClPB) or tridodecylomethylammonium chloride (TDDMACl) in order to improve the sensitivity and selectivity of the ISEs studied. Both types of the ISEs display good sensitivity, very short response time, and lack of interference from the major components of human plasma. The contents of salicylate in the samples of natural human plasma were determined by a potentiometric method using the electrode proposed. The results obtained were in good agreement withthose obtained by the Trinder spectrophotometry method. The ISEs incorporatingMn(III)‐porphyrin and Zn(II)‐ dipyrromethene are suitable for the direct determination of salicylate in human plasma.

Near-infrared organic photodetectors based on bay-annulated indigo showing broadband absorption and high detectivities up to 1.1 µm

Near-infrared photodetection is valuable for numerous scientific, industrial and recreational applications. The implementation of organic semiconductors in near-infrared photodetectors offers additional advantages, such as printability on flexible substrates, reduced manufacturing costs and facile tuning of the detection range. In this work, the nature-inspired bay-annulated indigo (BAI) dye is employed as a building block for near-infrared sensitive, push–pull type conjugated polymers. The electron-deficient BAI moiety is copolymerized with a set of electron-rich monomers, affording polymers with an absorption onset up to 1300 nm and a sufficiently high lowest unoccupied molecular orbital, allowing electron transfer to standard fullerene acceptors. Bulk heterojunction type organic photodetectors are fabricated and the resulting device characteristics are analysed. The best performing photodetector is based on the polymer PTTBAI comprising thieno[3,2-b]thiophene as the electron-rich moiety. It has a superior light to dark current ratio, with a dark current density of 10−7 A cm−2, resulting in a (shot-noise limited) detectivity of 1012 Jones at −2 V bias within the spectral window of 600–1100 nm, exceeding the detectivity of conventional silicon CCD photodetectors in the near-infrared region (∼1011 Jones).

Structure-property relations of high permittivity cathode interlayer materials toward bulk heterojunction organic solar cells(Conference Presentation)

Organic photovoltaics (OPV) show strong potential for a number of renewable energy applications because of some specifically appealing features (light weight, flexibility, color, …). Over the past decade, the power conversion efficiencies of organic solar cells have strongly risen to values surpassing the 10% threshold, mainly due to strong efforts in chemical engineering of the photoactive components, architectural device optimization and acquisition of fundamental insights in the underlying device physics. As part of the device optimization, the use of conjugated polyelectrolyte (CPE) interfacial layers has been introduced as a popular and powerful way to boost the inherent I-V characteristics. In the presented work, we applied impedance spectroscopy to probe the dielectric permittivity of a series of polythiophene-based CPE interlayer materials as a means to postulate design rules toward novel generation interfacial layers. The presence of ionic pendant groups grants the formation of a capacitive double layer, boosting the charge extraction and device efficiency. A counteracting effect is that the material’s affinity with respect to the underlying photoactive layer diminishes. To enhance the interlayer-photoactive layer compatibility, copolymer structures containing a certain amount of non-ionic side chains are found to be beneficial.