All‐Inkjet‐Printed,All‐Air‐Processed Solar Cells

The prospective of using direct‐write printing techniques for the manufacture of organic photovoltaics (OPVs) has made these techniques highly attractive. OPVs have the potential to revolutionize small‐scale portable electronic applications by directly providing electric power to the systems. However, no route is available for monolithically integrating the energy‐harvesting units into a system in which other components, such as transistors, sensors, or displays, are already fabricated. Here, the fabrication and the measurement of inkjet‐printed, air‐processed organic solar cells is reported for the first time. Highly controlled conducting and semiconducting films using engineered inks for inkjet printing enable good efficiencies for printed OPVs between ≈2 and 5% power conversion efficiency. The results show that inkjet printing is an attractive digital printing technology for cost‐effective, environmentally friendly integration of photovoltaic cells onto plastic substrates.     

Improved Performance and Stability of Inverted Organic Solar Cells with Sol–Gel Processed,Amorphous Mixed Metal Oxide Electron Extraction Layers Comprising Alkaline Earth Metals

Stability of organic photovoltaic devices (OPVs) is a limiting factor for their commercialization and still remains a major challenge whilst power conversion efficiencies are now approaching minimum requirements. The inverted organic solar cell (iOSC) architecture shows promising potential for improving significantly the cell's working lifetime. However, when solution processed ZnO is used as electron extraction layer, an undesirable light‐soaking step is commonly required before the device reaches a non‐permanent maximum performance. This work investigates the use of Sr and Ba doped ZnO films, ZnSrO and ZnBaO, formed by sol‐gel deposition using molecular alkoxide precursor solutions, as electron extraction layers in a model iOSCs with poly [3‐hexylthiophene] (P3HT): [6, 6]‐phenyl C60 butyl acid methyl ester (PCBM) as the active layer. We show that using these ternary oxides the light‐soaking step can be circumvented by preventing a dipole forming between the oxide and the active organic layer as supported by electroabsorption spectroscopy measurements of the device built‐in field. It is suggested that Sr or Ba doping results in suppression/reduction of the oxygen adsorption at mobile oxygen vacancy sites on the metal oxide surface. Like in thin film transistor (TFT) applications, where materials like InGaZnO are rapidly becoming an important technology, the use of amorphous, mixed metal oxides allows improving the performance and stability of interfacial charge extraction layers for organic solar cells.     

Do nitrogen fertilizers stimulate or inhibit methane emissions from rice fields?

In rice cultivation, there are controversial reports on net impacts of nitrogen (N) fertilizers on methane (CH ₄) emissions. Nitrogen fertilizers increase crop growth as well as alter CH ₄ producing (Methanogens) and consuming (Methanotrophs) microbes, and thereby produce complex effects on CH ₄ emissions. Objectives of this study were to determine net impact of N fertilizers on CH ₄ emissions and to identify their underlying mechanisms in the rice soils. Database was obtained from 33 published papers that contained CH ₄ emissions observations from N fertilizer (28–406 kg N ha^?1) treatment and its control. Results have indicated that N fertilizers increased CH ₄ emissions in 98 of 155 data pairs in rice soils. Response of CH ₄ emissions per kg N fertilizer was significantly (P < 0.05) greater at < 140 kg N ha^?1 than > 140 kg N ha^?1 indicating that substrate switch from CH ₄ to ammonia by Methanotrophs may not be a dominant mechanism for increased CH ₄ emissions. On the contrary, decreased CH ₄ emission in intermittent drainage by N fertilizers has suggested the stimulation of Methanotrophs in rice soils. Effects of N fertilizer stimulated Methanotrophs in reducing CH ₄ emissions were modified by the continuous flood irrigation due to limitation of oxygen to Methanotrophs. Greater response of CH ₄ emissions per kg N fertilizer in urea than ammonia sulfate probably indicated the interference of sulfate in the CH ₄ production process. Overall, response of CH ₄ emissions to N fertilizers was correlated with N‐induced crop yield (r = +0.39; P < 0.01), probably due to increased carbon substrates for Methanogens. Using CH ₄ emission observations, this meta‐analysis has identified dominant microbial processes that control net effects of N fertilizers on CH ₄ emissions in rice soils. Finally, we have provided a conceptual model that included microbial processes and controlling factors to predict effects of N fertilizers on CH ₄ emissions in rice soils.     

Complex Spatiotemporal Responses of Global Terrestrial Primary Production to Climate Change and Increasing Atmospheric CO2 in the 21st Century

Quantitative information on the response of global terrestrial net primary production (NPP) to climate change and increasing atmospheric CO₂ is essential for climate change adaptation and mitigation in the 21^st century. Using a process-based ecosystem model (the Dynamic Land Ecosystem Model, DLEM), we quantified the magnitude and spatiotemporal variations of contemporary (2000s) global NPP, and projected its potential responses to climate and CO₂ changes in the 21^st century under the Special Report on Emission Scenarios (SRES) A2 and B1 of Intergovernmental Panel on Climate Change (IPCC). We estimated a global terrestrial NPP of 54.6 (52.8–56.4) PgC yr⁻¹ as a result of multiple factors during 2000–2009. Climate change would either reduce global NPP (4.6%) under the A2 scenario or slightly enhance NPP (2.2%) under the B1 scenario during 2010–2099. In response to climate change, global NPP would first increase until surface air temperature increases by 1.5°C (until the 2030s) and then level-off or decline after it increases by more than 1.5°C (after the 2030s). This result supports the Copenhagen Accord Acknowledgement, which states that staying below 2°C may not be sufficient and the need to potentially aim for staying below 1.5°C. The CO₂ fertilization effect would result in a 12%–13.9% increase in global NPP during the 21^st century. The relative CO₂ fertilization effect, i.e. change in NPP on per CO₂ (ppm) bases, is projected to first increase quickly then level off in the 2070s and even decline by the end of the 2080s, possibly due to CO₂ saturation and nutrient limitation. Terrestrial NPP responses to climate change and elevated atmospheric CO₂ largely varied among biomes, with the largest increases in the tundra and boreal needleleaf deciduous forest. Compared to the low emission scenario (B1), the high emission scenario (A2) would lead to larger spatiotemporal variations in NPP, and more dramatic and counteracting impacts from climate and increasing atmospheric CO₂.     

Transmembrane domain histidines contribute to regulation of AE2-mediated anion exchange by pH

Activity of the AE2/SLC4A2 anion exchanger is modulated acutely by pH, influencing the transporter's role in regulation of intracellular pH (pH_i) and epithelial solute transport. In Xenopus oocytes, heterologous AE2-mediated Cl^–/Cl^– and Cl^–/HCO₃^– exchange are inhibited by acid pH_i or extracellular pH (pH_o). We have investigated the importance to pH sensitivity of the eight histidine (His) residues within the AE2 COOH-terminal transmembrane domain (TMD). Wild-type mouse AE2-mediated Cl^–/Cl^– exchange, measured as DIDS-sensitive ³⁶Cl^– efflux from Xenopus oocytes, was experimentally altered by varying pH_i at constant pH_o or varying pH_o. Pretreatment of oocytes with the His modifier diethylpyrocarbonate (DEPC) reduced basal ³⁶Cl^– efflux at pH_o 7.4 and acid shifted the pH_o vs. activity profile of wild-type AE2, suggesting that His residues might be involved in pH sensing. Single His mutants of AE2 were generated and expressed in oocytes. Although mutation of H1029 to Ala severely reduced transport and surface expression, other individual His mutants exhibited wild-type or near-wild-type levels of Cl^– transport activity with retention of pH_o sensitivity. In contrast to the effects of DEPC on wild-type AE2, pH_o sensitivity was significantly alkaline shifted for mutants H1144Y and H1145A and the triple mutants H846/H849/H1145A and H846/H849/H1160A. Although all functional mutants retained sensitivity to pH_i, pH_i sensitivity was enhanced for AE2 H1145A. The simultaneous mutation of five or more His residues, however, greatly decreased basal AE2 activity, consistent with the inhibitory effects of DEPC modification. The results show that multiple TMD His residues contribute to basal AE2 activity and its sensitivity to pH_i and pH_o. pH regulation; histidine residues; Cl^–/HCO₃^– exchange     

Impact of long-term additions of chemical fertilizers and farm yard manure on carbon and nitrogen sequestration under rice-cowpea cropping system in semi-arid tropics

Restoration of soil organic carbon (SOC) in arable lands represents potential sink for atmospheric CO₂. The strategies for restoration of SOC include the appropriate land use management, cropping sequence, fertilizer and organic manures application. To achieve this goal, the dynamics of SOC and nitrogen (N) in soils needs to be better understood for which the long-term experiments are an important tool. A study was thus conducted to determine SOC and nitrogen dynamics in a long-term experiment in relation to inorganic, integrated and organic fertilizer application in rice-cowpea system on a sandy loam soil (Typic Rhodualf). The fertilizer treatments during rice included (i) 100% N (@ 100 kg N ha^?1), (ii) 100% NP (100 kg N and 50 kg P₂O₅ ha^?1), (iii) 100% NPK (100 kg N, 50 kg P₂O₅ and 50 kg K₂O ha^?1) as inorganic fertilizers, (iv) 50% NPK + 50% farm yard manure (FYM) (@ 5 t ha^?1) and (v) FYM alone @ 10 t ha^?1 compared with (vi) control treatment i.e. without any fertilization. The N alone or N and P did not have any significant effect on soil carbon and nitrogen. The light fraction carbon was 53% higher in NPK + FYM plots and 56% higher in FYM plots than in control plots, in comparison to 30% increase with inorganic fertilizers alone. The microbial biomass carbon and water-soluble carbon were relatively higher both in FYM or NPK + FYM plots. The clay fraction had highest concentration of C and N followed by silt, fine sand and coarse sand fractions in both surface (0–15 cm) and subsurface soil layers (15–30 cm). The C:N ratio was lowest in the clay fraction and increased with increase in particle size. The C and N enrichment ratio was highest for the clay fraction followed by silt and both the sand fractions. Relative decrease in enrichment ratio of clay in treatments receiving NPK and or FYM indicates comparatively greater accumulation of C and N in soil fractions other than clay.     

Do catecholestrogens interact with the in vitro binding of radioligands to catecholamine receptors?

Using a competitive binding assay the effects of 2-hydroxyestradiol-17 beta, 4-hydroxyestradiol-17 beta, estradiol-17 beta and progesterone on the binding of tritiated catecholaminergic ligands to membrane preparations from rat brain and pituitary gland were studied. Up to a concentration of 10(-5) M none of the steroids tested was able to displace [3H]spiroperidol, [3H]dihydroergocryptine or [3H]dihydroalprenolol. The data suggest that the catecholestrogens do not interfere directly with the binding of catecholaminergic ligands to dopaminergic, alpha-adrenergic or beta-adrenergic receptors in the central nervous system. The view that a catechol structure is not essential for the interaction with dopaminergic receptors was further supported by the results obtained from additional studies on the competition of O-methylated and deaminated dopamine metabolites with [3H]spiroperidol binding.