Benchmarking and validation of a combined CFD-optics solver for micro-scale problems

In this work, we present a new approach for coupled CFD-optics problems that consists of a combination of a finite element method (FEM) based flow solver with a ray tracing based tool for optic forces that are induced by a laser. We combined the open-source computational fluid dynamics (CFD) package FEATFLOW with the ray tracing software of the LAT-RUB to simulate optical trap configurations. We benchmark and analyze the solver first based on a configuration with a single spherical particle that is subjected to the laser forces of an optical trap. The setup is based on an experiment that is then compared to the results of our combined CFD-optics solver. As an extension of the standard procedure, we present a method with a time-stepping scheme that contains a macro step approach. The results show that this macro time-stepping scheme provides a significant acceleration while still maintaining good accuracy. A second configuration is analyzed that involves non-spherical geometries such as micro rotors. We proceed to compare simulation results of the final angular velocity of the micro rotor with experimental measurements

Der Einsatz des AutoPulse^®-Systems zur mechanischen Reanimation : Eine prospektive Beobachtungsstudie im Rettungsdienst der Stadt Bonn

Ziel dieser Pilotstudie war es, denn bereits routinemäßigen Gebrauch des AutoPulse® im Rettungsdienst der Stadt Bonn strukturierter und effizienter im Hinblick auf die geplante prospektiv randomisierte Studie zu gestalten. Wir entwickelten einen AutoPulse®-Algorithmus zur Integrität des neuen Rettungsmittels zwecks schnellen zeitnahen Einsatzes des Systems sowie einer möglichst geringen Unterbrechung der manuellen Herzdruckmassage. In einer Videoanalyse wurden insgesamt 38 Aufnahmen von Simulationstrainings an Reanimationspuppen in Bezug auf verschiedene Wegpunkte dieses Algorithmus (schnelle Vitalzeichenkontrolle, zügiger CPR-Beginn, Vorbereitung des Patienten zur System-Anlage, schnelle Anbringen des Rettungsmittel am Patienten) ausgewertet, um dessen Praktikabilität zu überprüfen. Es zeigte sich, dass die formulierten zeitlichen Zielvorgaben erfüllt werden konnten. Im Feldversuch wurden insgesamt 192 präklinische Reanimationen prospektiv erfasst, wovon 124 mit dem neuen Rettungsmittel erfolgt waren. Die Nachverfolgung der Patienten im Krankenhaus mit Hilfe der Arztbriefe gelang in 110 Fällen. Für die Detailauswertungen der AutoPulse®-Reanimationen (z.B. hands-off-time zur System- Anlage, hands-off-ratio verschiedener CPR-Abschnitte) war eine lückenlose elektronische Aufzeichnung der CPR notwendig. Deshalb konnten insgesamt 52 mechanische Reanimationen eingeschlossen werden. Trotz einer zunächst höheren Unterbrechungszeit ist die hands-off-time nach erfolgter Systemanlage unter mechanischer Reanimation im weiteren Verlauf im Trend niedriger als unter konventioneller manueller Herzdruckmassage. Die System-Anlage dauerte unter realen Einsatzbedingungen etwas länger und die Eintreffzeiten des Gerätes an der Einsatzstelle waren größer als erwartet. Abschließend läßt sich feststellen, dass auch unter mechanischer Reanimation das Überleben in den ersten 24 Stunden das gleiche Verteilungsmuster wie unter manueller Herzdruckmassage aufweist. Die Daten dieser Arbeit zeigen, dass eine mechanische Reanimationshilfe wie das AutoPulse®-System der Firma Zoll sinnvoll in den CPR-Algorithmus der ERC-Richtlinien integriert werden kann, ohne dass dabei das Ziel einer möglichst geringen Unterbrechungszeit der Herzdruckmassage aufgeben zu müssen. Darüber hinaus ist nach entsprechendem Training der Anwender ein Einsatz des Geräts mit vertretbarer Unterbrechung der Herzdruckmassage zur Anlage am Patienten unter realen und ständig wechselnden Einsatzsituationen möglich. Es konnten so die Voraussetzungen und Bedingungen für eine prospektiv-randomisierte vergleichende Untersuchung zwischen der manuellen und der mechanischen Reanimation geschaffen werden. Ob der Einsatz von solchen mechanischen Reanimationshilfen tatsächlich einen Einfluß auf das Überleben der Betroffenen haben kann, ist mit diesen Daten nicht zu beantworten und ist Gegenstand der im Anschluss geplanten Untersuchungen

3D Traction Forces in Cancer Cell Invasion

Cell invasion through a dense three-dimensional (3D) matrix is believed to depend on the ability of cells to generate traction forces. To quantify the role of cell tractions during invasion in 3D, we present a technique to measure the elastic strain energy stored in the matrix due to traction-induced deformations. The matrix deformations around a cell were measured by tracking the 3D positions of fluorescent beads tightly embedded in the matrix. The bead positions served as nodes for a finite element tessellation. From the strain in each element and the known matrix elasticity, we computed the local strain energy in the matrix surrounding the cell. We applied the technique to measure the strain energy of highly invasive MDA-MB-231 breast carcinoma and A-125 lung carcinoma cells in collagen gels. The results were compared to the strain energy generated by non-invasive MCF-7 breast and A-549 lung carcinoma cells. In all cases, cells locally contracted the matrix. Invasive breast and lung carcinoma cells showed a significantly higher contractility compared to non-invasive cells. Higher contractility, however, was not universally associated with higher invasiveness. For instance, non-invasive A-431 vulva carcinoma cells were the most contractile cells among all cell lines tested. As a universal feature, however, we found that invasive cells assumed an elongated spindle-like morphology as opposed to a more spherical shape of non-invasive cells. Accordingly, the distribution of strain energy density around invasive cells followed patterns of increased complexity and anisotropy. These results suggest that not so much the magnitude of traction generation but their directionality is important for cancer cell invasion

MADS-complexes regulate transcriptome dynamics during pollen maturation

Pollen transcript profiling of mutants defective in MADS-domain MIKC* protein complexes suggests they control a transcriptional network directing cellular differentiation during pollen maturation

Scenarios for sustainable heat supply in cities – case of Helsingor, Denmark

Local climate action is not only a domain of large cities, but also smaller urban areas that increasingly address climate change mitigation in their policy. The Danish municipality of Helsingør can achieve substantial CO2 emission reduction by transforming its heat supply and deploying heat savings. In the paper we model the heating system of Helsingør from a socio- and private-economic perspective, develop future scenarios, and conduct an iterative process to derive optimal mix between district heating, individual heating and heat savings. The results show that in 2030 it is cost-optimal to reduce the heating demand by 20-39% by implementing heat savings, to deploy 33%-41% of district heating and reduce heating-related CO2 emissions by up to 95% compared to now. In 2050, the cost-optimal share of district heating in Helsingør is between 38-44%. The resulting average heating costs and CO2 emissions are found to be sensitive to biomass and electricity price. Although the findings of the study are mainly applicable for Helsingør, the combined use of the Least Cost Tool and modelling with energyPRO is useful in planning of any heating and/or cooling supply and demand configuration, in any geographical region and scal

Scenarios for sustainable heat supply and heat savings in municipalities - The case of Helsingor, Denmark

Local climate action is not only a domain of large cities, but also smaller urban areas that increasingly address climate change mitigation in their policy. The Danish municipality of Helsingør can achieve a substantial CO2 emissions reduction by transforming its heat supply and deploying heat savings. In this paper, we model the heating system of Helsingør, assess it from a simple socio- and private-economic perspective, develop future scenarios, and conduct an iterative process to derive a cost-optimal mix between district heating, individual heating and heat savings. The results show that in 2030 it is cost-optimal to reduce the heating demand by 20-39% by implementing heat savings, to deploy 32%-41% of district heating and to reduce heating-related CO2 emissions by up to 95% in comparison to current emissions. In 2050, the cost-optimal share of district heating in Helsingør increases to between 38-44%. The resulting average heating costs and CO2 emissions are found to be sensitive to biomass and electricity price. Although the findings of the study are mainly applicable for Helsingør, the combined use of the Least Cost Tool and modelling with energyPRO is useful in planning of heating and/or cooling supply for different demand configurations, geographical region and scale

Scenarios for sustainable heat supply in cities – case of Helsingor, Denmark

Local climate action is not only a domain of large cities, but also smaller urban areas that increasingly address climate change mitigation in their policy. The Danish municipality of Helsingør can achieve substantial CO2 emission reduction by transforming its heat supply and deploying heat savings. In the paper we model the heating system of Helsingør from a socio- and private-economic perspective, develop future scenarios, and conduct an iterative process to derive optimal mix between district heating, individual heating and heat savings. The results show that in 2030 it is cost-optimal to reduce the heating demand by 20-39% by implementing heat savings, to deploy 33%-41% of district heating and reduce heating-related CO2 emissions by up to 95% compared to now. In 2050, the cost-optimal share of district heating in Helsingør is between 38-44%. The resulting average heating costs and CO2 emissions are found to be sensitive to biomass and electricity price. Although the findings of the study are mainly applicable for Helsingør, the combined use of the Least Cost Tool and modelling with energyPRO is useful in planning of any heating and/or cooling supply and demand configuration, in any geographical region and scal