Elucidation of the Structure of Solanoeclepin A, a Natural Hatching Factor of Potato and Tomato Cyst Nematodes, by Single-crystal X-ray Diffraction

Potato crops can be severely damaged by potato cyst nematodes Globodera rostochiensis and Globodera pallida, nematodes highly specific to potatoes and some other Solanaceae. Hatching of juveniles is controlled by agents excreted by the roots of some Solanaceae species. Over seventy years much effort has been expended by many groups to isolate these agents and to determine their structures. However, all attempts have failed. We report here the structure determination of a hatching factor excreted from potato and tomato roots. The hatching factor bears some resemblance to Glycinoeclepins as found by Masamune et al.2-5 and is hence designated as Solanoeclepin A.1 C27H30O9.3H2O, Mr = 498.5, monoclinic, P21, a = 11.289(2), b = 20.644(4), c = 11.632(12) Å, β = 90.81(4), V = 2711(3) Å3, Z = 4, Dx = 1.35 g cm–3, λ(Cu-K&alpha ) = 1.5418 Å, μ(Cu-Kα ) = 9.0 cm–1, F(000) = 1176, –60 °C. Final R = 0.117 for 3721 observed reflections

Different Transcript Patterns in Response to Specialist and Generalist Herbivores in the Wild Arabidopsis Relative Boechera divaricarpa

BACKGROUND: Plants defend themselves against herbivorous insects, utilizing both constitutive and inducible defenses. Induced defenses are controlled by several phytohormone-mediated signaling pathways. Here, we analyze transcriptional changes in the North American Arabidopsis relative Boechera divaricarpa in response to larval herbivory by the crucifer specialist lepidopteran Plutella xylostella (diamondback moth) and by the generalist lepidopteran Trichoplusia ni (cabbage semilooper), and compare them to wounding and exogenous phytohormone application. METHODOLOGY/PRINCIPAL FINDINGS: We use a custom macroarray constructed from B. divaricarpa herbivory-regulated cDNAs identified by suppression subtractive hybridization and from known stress-responsive A. thaliana genes for transcript profiling after insect herbivory, wounding and in response to jasmonate, salicylate and ethylene. In addition, we introduce path analysis as a novel approach to analyze transcript profiles. Path analyses reveal that transcriptional responses to the crucifer specialist P. xylostella are primarily determined by direct effects of the ethylene and salicylate pathways, whereas responses to the generalist T. ni are influenced by the ethylene and jasmonate pathways. Wound-induced transcriptional changes are influenced by all three pathways, with jasmonate having the strongest effect. CONCLUSIONS/SIGNIFICANCE: Our results show that insect herbivory is distinct from simple mechanical plant damage, and that different lepidopteran herbivores elicit different transcriptional responses

Pressure Drop Analysis of Steam Generation Parabolic Trough Plants

Direct steam generation (DSG) in parabolic trough plants has the potential to be more cost-effective than oil based systems. The produced steam can directly be used for process heat applications. Within the P3 project such a DSG plant of 108 m2 of Solitem’s PTC1800 has been installed on the roof of the building of the company Alanod. In the present paper, a two-phase pressure drop analysis of typical steam generation plants with different layouts is presented. A static model has been developed for this purpose. Parametric studies have shown that, due to the elevated pressure drops, the length of a collector loop within a DSG plant is limited. Consequently, in bigger plants collector loops need to be installed in parallel. In each collector loop so-called Ledinegg instabilities occur. When collector loops are installed in parallel, there are additional flow instabilities. Those parallel flow instabilities occure due to shading of one or several collector loops. Changing pressure drops lead to an unfavourable reallocation of mass flows. In the worst case, steam is superheated and the collectors get damaged due to high temperatures. Ledinegg and parallel flow instabilities can both be reduced by installing an additional flow resistor at the collector loop’s inlet

Energetic Comparison of Linear Fresnel and Parabolic Trough Collector Systems

Within the last years, Linear Fresnel (LF) collector systems have been developed as a technical alternative to parabolic trough collector (PT) systems. In the past, LF systems focused on low- and medium temperature applications. Nowadays, LF systems equipped with vacuum receivers can be operated at the same temperatures as PT systems. Papers about the technical and economical comparison of specific PT and LF systems have already been published, [1-3]. However, the present paper focuses on the systematic differences in optical and thermodynamic performance and the impact on the economic figures In a first step the optical performance of typical PT and LF solar fields has been examined, showing the differences during the course of the day and annually. Furthermore, the thermodynamic performance, depending on the operating temperature, has been compared. In a second step, the annual electricity yield of typical PT and LF plants are examined. Solar Salt has been chosen as heat transfer fluid. Both systems utilize the same power block and storage type. Solar field size, storage capacity, and power block electrical power are variable, while all examined configurations achieve the same annual electricity yield. As expected for molten salt systems, both systems are the most cost-effective with large storage capacities. The lower thermodynamic performance of the LF system requires a larger solar field and lower specific costs in order to be competitive. Assuming specific PT field costs of 300 €/m² aperture, the break-even costs of the LF system with Solar Salt range between 202 and 235 €/m², depending on the site and storage capacity. Keywords: linear Fresnel, parabolic trough

Synthesis of DNI time series with sub-hourly time resolution

The output of a CSP plant shows a non-linear response to the incoming direct normal irradiance. Due to inertia of the various sub-systems and part-load effects for a proper modelling of their energy yield, information on the DNI with high time-resolution is necessary down to the one minute scale. As this type of data is only scarcely available, tools for the synthetisation of these sets have to be applied. We have adopted a respective procedure for the use in the context of yield prediction. The performance of the procedure is, on the one hand tested for the statistical similarity of measured and synthesised data. On the other hand, the applicability of the synthetic sets is checked by comparing the outcomes of a transient plant simulation model for both types of data. The paper gives results from these tests and draws conclusions concerning further improvements of the scheme for the synthesis

Computersimulation eines hybridisierten Brennstoffzellenfahrzeugs

Das Ziel der vorliegenden Diplomarbeit war es, ein hybridisiertes Brennstoffzellenfahrzeug "HyLite" durch ein rechnergestütztes Modell abzubilden und zu verifizieren. Das HyLite-Fahrzeug dient als Komponententräger für zukünftige Antriebssysteme und wurde am Institut für Fahrzeugkonzepte (FK) des Deutschen Zentrums für Luft- und Raumfahrt (DLR) in Stuttgart entwickelt und getestet. Es verfügt über einen leistungsverzweigten Antriebsstrang, in dem eine Brennstoffzelle als Hauptenergielieferant für den elektrischen Antrieb dient. Um Leistungsspitzen abzudecken, ist zusätzlich eine Pufferbatterie integriert. Parallel wird am DLR an einer Modellbibliothek (AlternativeVehicles) in der Modellierungssprache Modelica gearbeitet, die zur Simulation innovativer Fahrzeugkonzepte dient. Das Fahrzeug-Modell wurde auf Basis von Komponenten aus dieser Bibliothek aufgebaut. Um Komponentenmodelle zu parametisieren (z.B. Elektromotor, Batterie) mussten vorliegende Messdaten verwendet und teilweise neu ausgewertet werden. Parameter für den Fahrwiderstand wurden durch umfangreiche Messungen auf dem Rollenprüfstand des DLR ermittelt. Als Grundlage für eine Fahrsimulation wurde dem Modell ein gemessenes Fahrprofil (Sollgeschwindigkeit über Zeit) einer Testfahrt des HyLite-Fahrzeugs vorgegeben. Ziel war es, das Verhalten des Modells möglichst genau an das Verhalten des realen Fahrzeugs anzugleichen. Mit einem im Rahmen der Diplomarbeit erstellten Matlab-Skript konnten Messwerte der Testfahrt mit denen aus der Simulation verglichen werden. Die kontinuierliche Anpassung des Modells führte zu einer guten Übereinstimmung zwischen simulierter und realer Testfahrt. Verbesserungspotenziale am Fahrzeug, vor allem in der Luftversorgung der Brennstoffzelle und in der Betriebsstrategie, wurden durch die Simulation aufgezeigt. Entsprechend wurden Vorschläge für Veränderungen an der Fahrzeugsteuerung gemacht. Mit dem HyLite-Modell gelang es, eine Plattform zu schaffen, auf der Modifizierungen erprobt werden können, bevor sie im realen Fahrzeug implementiert werden. Dabei wurde außerdem die Praxisrelevanz der Fahrzeugsimulation mit Komponenten aus der AlternativeVehicles-Bibliothek unter Beweis gestellt