Membrane Based Measurement Technology for in situ Monitoring of Gases in Soil

The representative measurement of gas concentration and fluxes in heterogeneous soils is one of the current challenges when analyzing the interactions of biogeochemical processes in soils and global change. Furthermore, recent research projects on CO2-sequestration have an urgent need of CO2-monitoring networks. Therefore, a measurement method based on selective permeation of gases through tubular membranes has been developed. Combining the specific permeation rates of gas components for a membrane and Dalton's principle, the gas concentration (or partial pressure) can be determined by the measurement of physical quantities (pressure or volume) only. Due to the comparatively small permeation constants of membranes, the influence of the sensor on its surrounding area can be neglected. The design of the sensor membranes can be adapted to the spatial scale from the bench scale to the field scale. The sensitive area for the measurement can be optimized to obtain representative results. Furthermore, a continuous time-averaged measurement is possible where the time for averaging is simply controlled by the wall-thickness of the membrane used. The measuring method is demonstrated for continuous monitoring of O2 and CO2 inside of a sand filled Lysimeter. Using three sensor planes inside the sand pack, which were installed normal to the gas flow direction and a reference measurement system, we demonstrate the accuracy of the gas-detection for different flux-based boundary conditions

FNTB promoter polymorphisms are associated with survival in different cancers

Ziel der vorliegenden Untersuchungen war die strukturelle und funktionelle Analyse der Promotorregion des Gens FNTB. Dieses kodiert für die β-Untereinheit der Farnesyltransferase, ein Enzym, das für die posttranslationale Modifikation zahlreicher Moleküle verantwortlich ist und zurzeit im Fokus von klinischen Studien zur Evaluation von Farnesyltransferaseinhibitoren (FTI), einem neuen Ansatz in der Tumortherapie, steht. Wir konnten drei Polymorphismen validieren: Dies waren die Basenaustausche (single nucleotide polymorphisms (SNPs)) FNTB -609 G>C, FNTB -179 T>A und FNTB -173 6G>5G. Bei der funktionellen Analyse der SNPs FNTB -609 und FNTB -173 zeigten sich deutliche Unterschiede bei der Bindung von Transkriptionsfaktoren sowie der mRNA Expression abhängig vom Genotyp. Hierbei zeigten die Allele FNTB -609 G sowie FNTB -173 5G eine stärkere Transkriptionsfaktor-Bindung sowie eine erhöhte mRNA-Expression. Bei der Überlebensanalyse unterschiedlicher Tumorkollektive fanden sich für diese Allele höhere Überlebensraten im Vergleich zu den komplementären Allelen: Der SNP FNTB -609 zeigte Unterschiede im Überleben bei Patienten mit multiplem Myelom (5-Jahres-Überlebensrate (5-JÜR) 59,1 % für den GG-Gentotyp vs. 32,9 % für den CC-Genotyp, p = 0,038) sowie bei Patienten mit Nierenzell-Karzinom (10-JÜR 77,3 % für den GG-Gentyp vs. 0 % für den CC-Genotyp, p = 0,003). Der SNP FNTB -173 zeigte Unterschiede im Überleben bei Patientinnen mit Mamma-Karzinom (5-JÜR 100 % für den 5G/5G-Genotyp vs. 73,1 % für den 6G/6G-Genotyp, p = 0,044) sowie bei Patienten mit Melanom (10-JÜR 57,7 % für den 5G/5G-Genotyp vs. 0 % für den 6G/6G-Genotyp, p = 0,001). In diesem Kollektiv fiel außerdem ein Unterschied der Genotyp-Verteilung im Vergleich zu gesunden Kaukasiern zu Gunsten des 5G-Allels auf. Die Odds Ratios betrugen 2,9 [1,34 – 6,64] (5G vs. 6G), 1,9 [1,33 – 2,83] (5G/6G vs. 6G) sowie 2,1 [1,43 – 2,97] (5G + 5G/6G vs. 6G). Die vorliegenden Ergebnisse lassen den Schluss zu, dass die Farnesylierung von Proteinen tumorsupressiven Charakter hat. Trotzdem zeigen einige klinische Studien positive Erfolge in der Tumortherapie mit FTIs. Mittlerweile ist bekannt, dass viele Moleküle in Anwesenheit von FTIs durch alternative Enzyme prenyliert werden, so dass mit den bisher bekannten Zielstrukturen der Farnesyltransferase noch keine zufrieden stellende Erklärung für die (teilweise divergenten) Studienergebnisse gefunden werden kann. Zum heutigen Stand der Forschung ist das Schlüsselprotein in der Tumortherapie mit Farnesyltransferaseinhibitoren weiterhin unbekannt, möglicherweise sind sogar je nach Tumorart unterschiedliche Moleküle für das Ansprechen auf FTIs verantwortlich. Unsere Ergebnisse können einen Beitrag zum Verständnis der Funktion der Farnesyltransferase liefern und sollten in zukünftigen Studien Berücksichtigung finden, wenn es um die klinische Evaluation von Tumortherapeutika sowie die Prognose von Tumorerkrankungen geht.Background: Farnesyltransferase inhibitors (FTIs) showed promising results in vitro while their clinical usefulness remains to be proven. The identification of biomarkers that could identify cancer patients who benefit from treatment with FTIs would be highly important. Therefore, we searched for polymorphisms in the gene encoding the farnesyltranserase β-subunit (FNTB) which could potentially be associated with treatment response to FTIs. Methods: The gene FNTB including its promoter region were sequenced. Functional properties of detected polymorphisms were evaluated by electrophoretic mobility shift assays (EMSA) and reporter assays. Healthy blood donors and patients with different malignancies (multiple myeloma, breast cancer, renal cell cancer and melanoma) were retrospectively genotyped for the detected polymorphisms. Polymorphisms were analyzed for linkage equilibrium and possible association of genotypes as well as haplotypes with risk for cancer and disease progression. FNTB expression in normal and cancer tissue samples were analyzed by quantitative real-time PCR. Both genotypes and diplotypes were correlated with FNTB expression and the patients’ survival. Results: Three promoter polymorphisms were detected, -609G/C, -179T/A, and -173delG (minor allelic frequencies 0.38, 0.06 and 0.28, respectively). The two more common of them were subject of further examination. They showed significantly altered binding of transcription factors in ESMA experiments, significant genotype- and haplotype-dependent differences of promoter activity, and genotype-dependently altered FNTB expression both in tumor tissue as well as in lymphocytes from healthy subjects. Kaplan-Meier curves revealed a significant and independent association of the polymorphisms and diplotypes with survival in all 4 cancers. Conclusions: Functional FNTB promoter polymorphisms determine FNTB expression levels and indicate high risk groups within different cancers. Our results suggest that genotyping of the FNTB polymorphisms could predict responders/non-responders of cancer patients treated with FTIs

Time resolved spatially-averaged set up for in situ CO2 monitoring in soil

Most studies in the past focus on the measurement of CO2 release from the soil surface, which is the parameter of interest for balancing carbon fluxes. However, for advancing our mechanistic understanding measurement of CO2 concentration within the soil are required. Soil CO2 concentrations do not only relate directly to local production of CO2 by plants and soil biota, but are also a key for understanding soil solution chemistry (in particular pH dynamics). The relationship between soil CO2 concentration and CO2 flux at the soil surface will depend on the chemical gradients, the size and connectivity of air filled pore space (related to soil structure and actual water content), and temperature gradients in the system. CO2 production as well as soil water content and temperature show temporal variation directly or indirectly related to day night cycle and related plant growth. It was the aim of the present study to test a recently developed linear membrane-based gas sensor (line sensor) for in situ measurement of soil respiration at high temporal resolution. Data from two soil depths were related to measurement of CO2 flux at the soil surface. Simultaneously, soil temperature, soil water content, and soil matric potential were measured at high temporal resolution in the respective depths. The measurements were conducted in 50 x 50 x 50 cm boxes filled with topsoil material from a Chernozem. To evaluate the sensitivity of the measurement system we compared a treatment planted with barley (Hordeum vulgare) to one without plants (three replications each). Besides a detailed description of the experimental set-up we will present and discuss first results from this new system

GT2008-50679 THE ENGINE 3E CORE ENGINE

ABSTRACT Engine 3E is the aero engine part of the German Aeronautics Research Program under which Rolls-Royce Deutschland developed key technologies for an all new core engine that incorporates major advances with regard to environmental friendliness, efficiency and economy. The derived E3E core engine will serve as a scalable baseline for the future two-shaft engine family in the medium take-off thrust range between 12 -40 klb. The core consists of a highly loaded 9-stage HPC, a lean burn combustion chamber with internal fuel staging and a 2-stage shroudless HPT. On the basis of its high specific power, low NOx combustion and low manufacturing cost, it will enable significant improvements in SFC, emissions, unit cost and weight. The related technology demonstrator is currently in the final build and instrumentation phase for testing in an altitude test facility in first quarter 2008

Ultrasonic Time Synchronization and Ranging on Smartphones

Abstract-In this paper, we present the design and evaluation of a platform that can be used for time synchronization and indoor positioning of mobile devices. The platform uses the Time-Difference-Of-Arrival (TDOA) of multiple ultrasonic chirps broadcast from a network of beacons placed throughout the environment to find an initial location as well as synchronize a receiver's clock with the infrastructure. These chirps encode identification data and ranging information that can be used to compute the receiver's location. Once the clocks have been synchronized, the system can continue performing localization directly using Time-of-Flight (TOF) ranging as opposed to TDOA. This provides similar position accuracy with fewer beacons (for tens of minutes) until the mobile device clock dirfts enough that a TDOA signal is once again required. Our hardware platform uses RF-based time synchronization to distribute clock synchronization from a subset of infrastructure beacons connected to a GPS source. Mobile devices use a novel time synchronization technique leverages the continuously freerunning audio sampling subsystem of a smartphone to synchronize with global time. Once synchronized, each device can determine an accurate proximity from as little as one beacon using Time-Of-Flight (TOF) measurements. This significantly decreases the number of beacons required to cover an indoor space and improves performance in the face of obstructions. We show through experiments that this approach outperforms the Network Time Protocol (NTP) on smartphones by an order of magnitude, providing an average 720µs synchronization accuracy with clock drift rates as low as 2ppm