Opportunities (‘costs) matter: A comment on Pimentel and Patzek “Ethanol production using corn,switchgrass, and wood; biodiesel production using soybean and sunflower”

The energy balance for different crops reported by Pimentel and Patzek ignores opportunity costs. Including opportunity costs substantially changes the results and leads to different conclusions.     

Wind energy statistics for large arrays of wind turbines (New England and Central U.S. Regions)

The performance characteristics have been simulated for large dispersed arrays of 500–1500 kW wind turbines producing power and feeding it directly into the New England or Central U.S. utility distribution grids. These studies, based on design power performance curves, indicate that in good wind environments the 500 kW generators can average (on an annual basis) up to 240 kW mean power output, and the 1500 kW generators can average up to 350 kW mean power output. Higher mean power output (averaging up to 470 kW) is indicated, however from a hypothetical 1125 kW rated power unit designed to operate at wind speeds near those observed throughout the study area, rather than the higher design operating wind speed of the 1500 kW unit. The beneficial effect of operating large disperse arrays of wind turbines is that available power output can be increased—if winds are not blowing over one part of the array, chances are they will over some other part of the array. These studies indicate that wind power availability levels of 200 kW per 1125 kW generator were 77–93 per cent, depending on season. Reasonably steady high wind power in winter and high afternoon peak wind power in summer (corresponding to peak air conditioning load) means that significant peak load displacement can be achieved without the use of storage.     

CRISPR/Cas9-RNA interference system for combinatorial metabolic engineering of Saccharomyces cerevisiae

The yeast Saccharomyces cerevisiae is widely used in industrial biotechnology for the production of fuels, chemicals, food ingredients, food and beverages, and pharmaceuticals. To obtain high-performing strains for such bioprocesses, it is often necessary to test tens or even hundreds of metabolic engineering targets, preferably in combinations, to account for synergistic and antagonistic effects. Here, we present a method that allows simultaneous perturbation of multiple selected genetic targets by combining the advantage of CRISPR/Cas9, in vivo recombination, USER assembly and RNA interference. CRISPR/Cas9 introduces a double-strand break in a specific genomic region, where multiexpression constructs combined with the knockdown constructs are simultaneously integrated by homologous recombination. We show the applicability of the method by improving cis,cis-muconic acid production in S. cerevisiae through simultaneous manipulation of several metabolic engineering targets. The method can accelerate metabolic engineering efforts for the construction of future cell factories.     

A simple hourly clear-sky solar radiation model based on meteorological parameters

An hourly solar radiation model, based on observed meteorological data, was developed and tested. As a means of comparison, the Watt and Bird models and the Solmet regression models were also tested. Several conclusions were drawn about the parameterization of solar radiation-depleting parameters. It was determined that a reasonable estimate of lower layer aerosol extinction can be determined using humidity, visibility, and mixing height. The parameterization of water vapor absorption obtained by atmospheric rather than laboratory observations was found to give better model results.     

Epoxyeicosatrienoic Acid and Prostanoid Crosstalk at the Receptor and Intracellular Signaling Levels to Maintain Vascular Tone

Epoxyeicosatrienoic acids (EETs) are signaling lipids produced by the cytochrome P450-(CYP450)-mediated epoxygenation of arachidonic acid. EETs have numerous biological effects on the vascular system, but aspects including their species specificity make their effects on vascular tone controversial. CYP450 enzymes require the 450-reductase (POR) for their activity. We set out to determine the contribution of endothelial CYP450 to murine vascular function using isolated aortic ring preparations from tamoxifen-inducible endothelial cell-specific POR knockout mice (ecPOR^−/−). Constrictor responses to phenylephrine were similar between control (CTR) and ecPOR^−/− mice. Contrastingly, sensitivity to the thromboxane receptor agonist U46619 and prostaglandin E2 (PGE2) was increased following the deletion of POR. Ex vivo incubation with a non-hydrolyzable EET (14,15-EE-8(Z)-E, EEZE) reversed the increased sensitivity to U46619 to the levels of CTR. EETs had no effect on vascular tone in phenylephrine-preconstricted vessels, but dilated vessels contracted with U46619 or PGE2. As U46619 acts through RhoA-dependent kinase, this system was analyzed. The deletion of POR affected the expression of genes in this pathway and the inhibition of Rho-GTPase with SAR407899 decreased sensitivity to U46619. These data suggest that EET and prostanoid crosstalk at the receptor level and that lack of EET production sensitizes vessels to vasoconstriction via the induction of the Rho kinase system.     

An integrated city-level planning process to address the impacts of climate change in Kenya: The case of Mombasa

Climate change presents one of the greatest challenges in urban development planning, yet leadership from planning can help society grapple with this challenge. Success in planning is especially important in coastal cities, where urbanization is heavily influenced by the coastline, and development planning processes have to take into consideration the socio-economic as well as ecological reasons why cities were located at the coast. This paper investigates the possibilities of and impediments to an integrated city-level planning framework that is responsive to climate change, using the case of the East African coastal city of Mombasa. It contends that both the principle of subsidiarity as well as the established law give the municipal government the necessary jurisdiction over the baseline issues underlying city management, which through stakeholder engagement, can be leveraged to facilitate an integrated climate change-responsive planning.     

Hyaluronan-based heparin-incorporated hydrogels for generation of axially vascularized bioartificial bone tissues: in vitro and in vivo evaluation in a PLDLLA–TCP–PCL-composite system

Smart matrices are required in bone tissue-engineered grafts that provide an optimal environment for cells and retain osteo-inductive factors for sustained biological activity. We hypothesized that a slow-degrading heparin-incorporated hyaluronan (HA) hydrogel can preserve BMP-2; while an arterio–venous (A–V) loop can support axial vascularization to provide nutrition for a bio-artificial bone graft. HA was evaluated for osteoblast growth and BMP-2 release. Porous PLDLLA–TCP–PCL scaffolds were produced by rapid prototyping technology and applied in vivo along with HA-hydrogel, loaded with either primary osteoblasts or BMP-2. A microsurgically created A–V loop was placed around the scaffold, encased in an isolation chamber in Lewis rats. HA-hydrogel supported growth of osteoblasts over 8 weeks and allowed sustained release of BMP-2 over 35 days. The A–V loop provided an angiogenic stimulus with the formation of vascularized tissue in the scaffolds. Bone-specific genes were detected by real time RT-PCR after 8 weeks. However, no significant amount of bone was observed histologically. The heterotopic isolation chamber in combination with absent biomechanical stimulation might explain the insufficient bone formation despite adequate expression of bone-related genes. Optimization of the interplay of osteogenic cells and osteo-inductive factors might eventually generate sufficient amounts of axially vascularized bone grafts for reconstructive surgery.     

Vier Jahre Docu-blogging im IT-Gipfel-Prozess der Bundesregierung Partizipation und Dokumentation leicht gemacht

Beim ersten nationalen IT-Gipfel 2006 in Potsdam wurde er?rtert, wie der deutsche IKT-Standort wieder an die Weltspitze kommen kann. Politik, Wirtschaft und Forschung diskutierten über neue Wachstumschancen und Arbeitspl?tze sowie über M?glichkeiten, wie zukunftstr?chtige Wachstumsfelder nachhaltig entwickelt werden k?nnen. Zahlreiche – darunter prominente – Stimmen kritisierten jedoch im Nachhinein, dass die breite und interessierte ?ffentlichkeit von dieser Diskussion ausgeschlossen blieb. Vor diesem Hintergrund wurde die M?glichkeit er?rtert, die erw?hnten inhaltlichen Resultate des IT-Gipfels über eine internetbasierte Kommunikationsplattform zur ?ffentlichen Diskussion bereitzustellen und damit der eingangs formulierten Kritik konstruktiv zu begegnen. Das Hasso-Plattner-Institut initiierte am 15. Juni 2007 als Antwort hierauf den IT-Gipfelblog. Inwieweit dieses Weblog bis heute dabei geholfen hat, neue, kreative und vision?re Ideen und Beitr?ge aus der interessierten ?ffentlichkeit zu den auf dem IT-Gipfel gestellten Fragen, den dort erarbeiteten Inhalten und den beschlossenen Ma?nahmen anzuregen und einzusammeln, ist Thema dieses Beitrags.