Bewertung der Verfügbarkeit von nicht extrahierbaren PAK-Rückständen im Boden

Polyzyklische aromatische Kohlenwasserstoffe (PAK) bilden im Boden nicht extrahierbare Rückstände (NER) aus. Ziel dieser Untersuchungen war es, die Verfügbarkeit von 14 C-markierten NER nach Anwendung unterschiedlicher Stressbedingungen zu charakterisieren und somit zu einer Bewertung der Stabilität von NER unter sich verändernden Umweltbedingungen beizutragen. Sowohl biologische als auch physikalische Behandlungen führten zu keiner relevanten Freisetzung von 14 C-Aktivität aus NER. Lediglich die chemische Destabilisierung von organischen Metallkomplexen mit EDTA zeigte einen Effekt auf die Stabilität der NER. Eine Freisetzung von 14 C-Aktivität in extrahierbarer Form fand statt. Entweder handelt es sich dabei um zuvor physikalisch eingeschlossene Moleküle oder um lösliche organische Substanz (DOM)

Reliability Goodness of Fit for Oil Spills in the Gulf of Mexico

Eschenbach and Harper (2006) analyzed offshore oil spills in the Gulf of Mexico with extensions to the northern seas of Alaska. This involved multiple methods including assessing what statistical distribution adequately fits the data. Empirical distribution function (EDF) statistical procedures are powerful goodness of fit tests and also provide for good visual assessments. The most powerful of the current EDF methods is the Anderson-Darling test. This paper focuses on the Anderson-Darling EDF goodness of fit procedure for both the two and three parameter Weibull distribution that is often used in reliability analysis. Excel VBA code has been developed to compute this test statistic and also the associated p-values to allow statistical significance tests. The Excel routines are available free at http://faculty.otterbein.edu/WHarper/. The functions are illustrated with Gulf of Mexico oil spill data

Reliability Confidence Intervals for Oil Spills in the Gulf of Mexico

An extensive study [Eschenbach and Harper (2006)] of offshore oil spills in the Gulf of Mexico with extensions to the northern seas of Alaska involved the estimation of the likelihood of oil spill volumes in the Gulf of Mexico for both pipeline and platform spills. This paper develops both maximum likelihood based reliability and percentile confidence intervals for the 3- parameter Weibull distribution. The statistical aspects are discussed along with applications of developed Excel VBA functions. The Excel routines are available free on the web at http://faculty.otterbein.edu/WHarper/. The functions are illustrated with Gulf of Mexico oil spill data

SPIN-MIMS simplifying the SPIN-MAS instrumentation for online measurement of 15N-abundances of ammonium, nitrite and nitrate in aqueous solutions

Common methods for measuring selectively the 15N abundances in individual N-species such as NH4+, NO2- and NO3- in samples with multiple N-species are laborious and time consuming. The SPIN-MAS technique (Stange et al. 2007) offers an automated, rapid and selective determination of 15N abundances in NH4+, NO2- and NO3- in aqueous samples. During a SPIN-MAS measurement one of three different reaction solutions is mixed with the aqueous sample in a Sample Preparation unit for Inorganic N-species (SPIN). The reaction solution is chosen in dependence on the N-species of interest. The gaseous reaction products (N2 or NO) are then conducted to a quadrupole mass spectrometer (MAS) in a helium stream. This measurement technique is not commonly used due to its complex instrumentation. The instrumentation can be significantly simplified by the use of a membrane inlet mass spectrometer (MIMS). The presented SPIN-MIMS approach relies on the use of a reaction capillary in which the sample containing the N-species of interest is mixed with the corresponding reaction solution. The mixture of reaction solution and sample is pumped from the reaction capillary directly to the membrane inlet of the mass spectrometer. The reaction products (N2 or NO) formed during the reaction of NH4+, NO2- and NO3- with the reaction solutions are passed through the gas-permeable membrane of the inlet directly into the ion source of the mass spectrometer. 15N standards with different at% 15N (NH4+, NO2- and NO3- respectively in dist. Water) were used to assess the performance of the system. Overall, SPIN-MIMS measurements showed a good agreement between measured and expected 15N abundances (range 0.36 – 10 at% 15N deviations: <0.5 at% 15N for NH4+-, <0.23 for NO2-- and <0.15 at% 15N for NO3-- standards)

Maximum Likelihood Estimation Methodology Comparison for the Three-Parameter Weibull Distribution with Applications to Offshore Oil Spills in the Gulf of Mexico

Maximum Likelihood estimation of the two-parameter Weibull distribution is straightforward; however, there are multiple methods for maximum likelihood estimation of the three-parameter Weibull. This paper presents an evaluation of these methods using four data sets including oil spill data from the Gulf of Mexico. Highlighted are fairly major differences in the estimated parameters between nine statistical packages. A VBA routine has been developed allowing practitioners to implement three-parameter Weibull maximum likelihood estimate within Excel. The code and support documentation are available free at http:faculty.otterbein.edu/WHarper

Myosin binding protein H-like (MYBPHL): a promising biomarker to predict atrial damage

Myosin binding protein H-like (MYBPHL) is a protein associated with myofilament structures in atrial tissue. The protein exists in two isoforms that share an identical amino acid sequence except for a deletion of 23 amino acids in isoform 2. In this study, MYBPHL was found to be expressed preferentially in atrial tissue. The expression of isoform 2 was almost exclusively restricted to the atria and barely detectable in the ventricle, arteria mammaria interna, and skeletal muscle. After atrial damage induced by cryo-or radiofrequency ablation, MYBPHL was rapidly and specifically released into the peripheral circulation in a time-dependent manner. The plasma MYBPHL concentration remained substantially elevated up to 24 hours after the arrival of patients at the intensive care unit. In addition, the recorded MYBPHL values were strongly correlated with those of the established biomarker CK-MB. In contrast, an increase in MYBPHL levels was not evident in patients undergoing aortic valve replacement or transcatheter aortic valve implantation. In these patients, the values remained virtually constant and never exceeded the concentration in the plasma of healthy controls. Our findings suggest that MYBPHL can be used as a precise and reliable biomarker to specifically predict atrial myocardial damage

caGrid-Enabled caBIGTM Silver Level Compatible Head and Neck Cancer Tissue Database System

There are huge amounts of biomedical data generated by research labs in each cancer institution. The data are stored in various formats and accessed through numerous interfaces. It is very difficult to exchange and integrate the data among different cancer institutions, even among different research labs within the same institution, in order to discover useful biomedical knowledge for the healthcare community. In this paper, we present the design and implementation of a caGrid-enabled caBIGTM silver level compatible head and neck cancer tissue database system. The system is implemented using a set of open source software and tools developed by the NCI, such as the caCORE SDK and caGrid. The head and neck cancer tissue database system has four interfaces: Web-based, Java API, XML utility, and Web service. The system has been shown to provide robust and programmatically accessible biomedical information services that syntactically and semantically interoperate with other resources

In vaginal fluid, bacteria associated with bacterial vaginosis can be suppressed with lactic acid but not hydrogen peroxide

<p>Abstract</p> <p>Background</p> <p>Hydrogen peroxide (H₂O₂) produced by vaginal lactobacilli is generally believed to protect against bacteria associated with bacterial vaginosis (BV), and strains of lactobacilli that can produce H₂O₂are being developed as vaginal probiotics. However, evidence that led to this belief was based in part on non-physiological conditions, antioxidant-free aerobic conditions selected to maximize both production and microbicidal activity of H₂O₂. Here we used conditions more like those <it>in vivo </it>to compare the effects of physiologically plausible concentrations of H₂O₂and lactic acid on a broad range of BV-associated bacteria and vaginal lactobacilli.</p> <p>Methods</p> <p>Anaerobic cultures of seventeen species of BV-associated bacteria and four species of vaginal lactobacilli were exposed to H₂O₂, lactic acid, or acetic acid at pH 7.0 and pH 4.5. After two hours, the remaining viable bacteria were enumerated by growth on agar media plates. The effect of vaginal fluid (VF) on the microbicidal activities of H₂O₂and lactic acid was also measured.</p> <p>Results</p> <p>Physiological concentrations of H₂O₂(< 100 μM) failed to inactivate any of the BV-associated bacteria tested, even in the presence of human myeloperoxidase (MPO) that increases the microbicidal activity of H₂O₂. At 10 mM, H₂O₂inactivated all four species of vaginal lactobacilli but only one of seventeen species of BV-associated bacteria. Moreover, the addition of just 1% vaginal fluid (VF) blocked the microbicidal activity of 1 M H₂O₂. In contrast, lactic acid at physiological concentrations (55-111 mM) and pH (4.5) inactivated all the BV-associated bacteria tested, and had no detectable effect on the vaginal lactobacilli. Also, the addition of 10% VF did not block the microbicidal activity of lactic acid.</p> <p>Conclusions</p> <p>Under optimal, anaerobic growth conditions, physiological concentrations of lactic acid inactivated BV-associated bacteria without affecting vaginal lactobacilli, whereas physiological concentrations of H₂O₂produced no detectable inactivation of either BV-associated bacteria or vaginal lactobacilli. Moreover, at very high concentrations, H₂O₂was more toxic to vaginal lactobacilli than to BV-associated bacteria. On the basis of these <it>in vitro </it>observations, we conclude that lactic acid, not H₂O₂, is likely to suppress BV-associated bacteria <it>in vivo</it>.</p