Modified Chaplygin Gas as a Unified Dark Matter and Dark Energy Model and Cosmic Constraints

A modified Chaplygin gas model (MCG), $\rho_{MCG}/\rho_{MCG0}=[B_{s}+(1-B_{s})a^{-3(1+B)(1+\alpha)}]^{1/(1+\alpha)}$, as a unified dark matter model and dark energy model is constrained by using current available cosmic observational data points which include type Ia supernovae, baryon acoustic oscillation and the seventh year full WMAP data points. As a contrast to the consideration in the literatures, we {\it do not} separate the MCG into two components, i.e. dark mater and dark energy component, but we take it as a whole energy component-a unified dark sector. By using Markov Chain Monte Carlo method, a tight constraint is obtained: $\alpha= 0.000727_{- 0.00140- 0.00234}^{+ 0.00142+ 0.00391}$, $B=0.000777_{- 0.000302- 0.000697}^{+ 0.000201+ 0.000915}$ and $B_s= 0.782_{- 0.0162- 0.0329}^{+ 0.0163+ 0.0307}$ .}Comment: 6 pages, 3 figure

Helium burning and neutron sources in the stars

Helium burning represents an important stage of stellar evolution as it contributes to the synthesis of key elements such as carbon, through the triple-alfa process, and oxygen, through the 12C(alfa, gamma)16O reaction. It is the ratio of carbon to oxygen at the end of the helium burning stage that governs the following phases of stellar evolution leading to different scenarios depending on the initial stellar mass. In addition, helium burning in Asymptotic Giant Branch stars, provides the two main sources of neutrons, namely the 13C(alfa, n)16O and the 22Ne(alfa, n)25Mg, for the synthesis of about half of all elements heavier than iron through the s-process. Given the importance of these reactions, much experimental work has been devoted to the study of their reaction rates over the last few decades. However, large uncertainties still remain at the energies of astrophysical interest which greatly limit the accuracy of stellar models predictions. Here, we review the current status on the latest experimental efforts and show how measurements of these important reaction cross sections can be significantly improved at next-generation deep underground laboratories

Rechtsmedizin / The potential of infrared pupillography in routine police traffic checks

Hintergrund: Um die Fahrtüchtigkeit eines Teilnehmers am Straßenverkehr evaluieren zu können, sind objektive und standardisierte Messmethoden notwendig. Auf die Anwendbarkeit und Wertigkeit der Infrarot-Pupillographie als objektive Messmethode für die Erkennung einer etwaigen Beeinflussung durch zentral-nervös wirksame Substanzen wurde bereits in mehreren Publikationen eingegangen. Ziel der Arbeit: Um an erste Ergebnisse unserer Studie anzuknüpfen war Ziel dieser Arbeit, die statistische Analyse auf weitere Parameter des Pupillenlichtreflexes (PLR) auszuweiten, um deren Relevanz und die Wertigkeit der Infrarot-Pupillographie für eine mögliche Implementierung in polizeiliche Routineverkehrskontrollen demonstrieren zu können. Material und Methoden: Die Iris gesunder Probanden (n = 41) sowie von Personen, die unter dem Einfluss zentral-nervös wirksamer Substanzen standen (n = 105), wurden unter Verwendung von Infrarottechnologie unterschiedlichen Lichtreizen ausgesetzt. Nach entsprechender Messung und Aufsplitten des PLR in Einzelparameter erfolgte die statistische Auswertung. Ergebnisse: Der PLR zeigt sich bei Personen, die unter der Wirkung zentral-nervös wirksamer Substanzen stehen, als signifikant verändert. In Übereinstimmung mit vorpublizierten Daten konnte bei der Mehrheit der Parameter die hohe Wertigkeit des PLR als verlässlicher Indikator für einen vorangegangenen Konsum von Drogen und/oder zentral-nervös wirksame Medikamente nachgewiesen werden. Die dafür aussagekräftigsten Parameter werden in der vorliegenden Studie präsentiert. Diskussion: Infrarot-Pupillographie repräsentiert eine objektive Untersuchungsmethode der Pupillenfunktion, die es ermöglicht, Hinweise auf eine mögliche Beeinflussung durch zentral-nervös wirksame Substanzen zu liefern. Die vorliegende Studie belegt die Anwendbarkeit des verwendeten Messinstrumentes für den mobilen Einsatz im Rahmen polizeilicher Routineverkehrskontrollen, so dass unseres Erachtens die Infrarot-Pupillographie künftig als ständige Methode in geplanten Polizeikontrollen, vorzugsweise in Zusammenarbeit mit rechts- bzw. verkehrsmedizinischen Zentren, zum Einsatz kommen sollte.Background: In order to evaluate driving abilities of each traffic participant, standardized and objective measurement methods are still needed. The applicability and value of infrared pupillography as an objective measurement method to indicate possible influence of central nervous acting substances has been demonstrated in former publications. Objectives: To tie in with first results of the study, the aim was to extend the statistical analysis to further parameters of the pupillary light reflex (PLR) in order to demonstrate their relevance and to substantiate the value of infrared pupillography for possible implementation in the framework of routine police traffic checks. Materials and methods: We exposed the iris of healthy test subjects (n = 41), as well as of persons who were under the influence of drugs and/or medication (n = 105), to different light stimuli using infrared technology. After measuring and splitting the PLR into single parameters a statistical analysis was performed. Results: The pupillary light reflex was significantly alterated when the examined person was under the influence of central nervous acting substances. In concordance with former reported results, the majority of the parameters approved the high value of the PLR as a reliable indicator of previous consumption of drugs and/or central nervous acting medication. The most appropriate parameters of the pupillary light reflex for identification of drivers under the influence of central nervous acting substances are indicated in the study. Conclusions: Infrared pupillography represents an objective method of measuring the pupil function to indicate a possible influence by central nervous acting substances. As we were able to prove the applicability of the device used in the present study during routine police traffic controls, we suggest that infrared pupillography should become a regular method in scheduled traffic controls in the future, preferably in cooperation with forensic medical centers.F.C. Monticelli, W. Hitzl, F. Priemer, U. Preiss, S.N. Kunz, T. Kelle

Hemodialysis and biotransformation of erythrocyte epoxy fatty acids in peripheral tissue

Cardiovascular disease is the leading cause of mortality in patients with renal failure. Red blood cells (RBCs) are potential reservoirs for epoxy fatty acids (oxylipins) that regulate cardiovascular function. Hemoglobin exhibits pseudo-lipoxygenase activity in vitro. We previously assessed the impact of single hemodialysis (HD) treatment on RBC epoxy fatty acids status in circulating arterial blood and found that eicosanoids in oxygenated RBCs could be particularly vulnerable in chronic kidney disease and hemodialysis. The purpose of the present study was to evaluate the differences of RBC epoxy fatty acids profiles in arterial and venous blood in vivo (AV differences) from patients treated by HD treatment. We collected arterial and venous blood samples in upper limbs from 12 end-stage renal disease (ESRD) patients (age 72±12 years) before and after HD treatment. We measured oxylipins derived from cytochrome P450 (CYP) monooxygenase and lipoxygenase (LOX)/CYP ω/(ω-1)-hydroxylase pathways in RBCs by LC-MS/MS tandem mass spectrometry. Our data demonstrate arteriovenous differences in LOX pathway metabolites in RBCs after dialysis, including numerous hydroxyeicosatetraenoic acids (HETEs), hydroxydocosahexaenoic acids (HDHAs) and hydroxyeicosapentaenoic acids (HEPEs). We detected more pronounced changes in free metabolites in RBCs after HD, as compared with the total RBC compartment. Hemodialysis treatment did not affect the majority of CYP and CYP ω/(ω-1)-hydroxylase products in RBCs. Our data indicate that erythro-metabolites of the LOX pathway are influenced by renal-replacement therapies, which could have deleterious effects in the circulation