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We present a method for the evaluation of fluorescence fluctuations on the basis of Mandel's Q parameter, using sampling time-dependent factorial cumulants. By relating the Q parameter to the sampling time, we obtain the mean single molecule rate (mSMR), an easy to interpret expression that provides both brightness and diffusion information. The model is suitable for the widely used confocal setups with single photon excitation and a single detection channel. We present a way to correct the mSMR for afterpulsing, dead time and background noise. To account for photokinetic effects at short sampling times, we expand the model by a simple on/off isomerization term, which is similar to the well-known triplet model. The functionality of the mSMR is shown using Monte Carlo simulations. The correction mechanisms and the experimental applicability of the model are then demonstrated by DNA measurements of defined composition. By systematically analyzing DNA mixtures, we can show that at large sampling times, the mSMR correctly describes the single molecule brightness rates and the diffusive properties of DNA molecules. At short sampling times, the photokinetic effects of isomerization are accurately described by the mSMR model. Since additionally the mSMR can easily be corrected for measurement artefacts such as detector dead time, afterpulsing and background noise, this is a valuable advantage over the standard method of fluorescence correlation spectroscopy.

BACKGROUND: The use of opioids for the treatment of pain is a risk versus benefit analysis and metabolic disease is an often overlooked variable in the equation and may lead to increased risk of comorbidities of cardiovascular and cerebrovascular disease and diabetes. OBJECTIVES: Our objective was to identify and describe abnormalities among the comprehensive metabolic and lipid panels of individuals taking prescription opioids. STUDY DESIGN: We performed a cross-sectional study of the laboratory values with 3 cycles (2011–2016) of the National Health and Nutrition Examination Survey (NHANES) in March 2020. SETTING: NHANES sampling is conducted using a multistaged, stratified, cluster sampling technique to create a representative sample of the United States. METHODS: We excluded patients with histories of cancer and under the age of 25 years. Our final sample size was 11,061 (n = 162,547,635), with 797 reportedly using a prescription opioid in the past 30 days—a weighted percent representing 22.95% of the US population. Our analyses identified mean differences in biomarkers between individuals taking prescription opioids and the US population. RESULTS: Laboratory values from the comprehensive metabolic panel were all within reference ranges for both groups, with only bilirubin levels being statistically lower in the group currently taking prescription opioids. Values from the lipid panel of both the opioid using and comparison groups were above reference range for total cholesterol and fasting glucose. The opioid using group was also higher than the reference range for triglycerides (mean [M] = 165.4, standard deviation [SD] = 14.2) and insulin (M = 15.5, SD = 2.2), whereas the comparison group was not. The oral glucose measure was within normal ranges for both groups; however, the opioid using group was 13.7 points higher than the comparison group (M = 122.3, SD = 1.8; M = 108.6, SD = 4.0; P < 0.01). LIMITATIONS: While our study uses a large sample for a robust generalizable analysis it is a correlation study and a longitudinal cohort would provide better evidence linking potential disease states to prescription opioid use. CONCLUSIONS: Although all Americans should be alarmed at the lipid levels reported in this study, specific combinations of heightened lipid laboratory values among prescription opioid users accelerate the trajectories toward comorbidities—heart disease, cerebrovascular disease, and diabetes—leading to diminished quality of life. Therefore pain management and comprehensive drug recovery programs should include nutritional counseling and physical activity as part of their overall treatment plan.

Determining the concentration of nucleic acids in biological samples precisely and reliably still is a challenge. In particular when only very small sample quantities are available for analysis, the established fluorescence-based methods give insufficient results. Photobleaching is seen as the main reason for this. In this paper we present a method to correct for the photobleaching effect. Using confocal microscopy with single molecule sensitivity, we derived calibration curves from DNA solutions with defined fragment length. We analyzed dilution series over a wide range of concentrations (1 pg/ml-1000 pg/ml) and measured their specific diffusion coefficients employing fluorescence correlation spectroscopy. Using this information, we corrected the measured fluorescence intensity of the calibration solutions for photobleaching effects. We evaluated our method by analyzing a series of DNA mixtures of varying composition. For fragments smaller than 1000 bp, our method allows to determine sample concentrations with high precision in very small sample quantities (< 2 ml with concentrations < 20 pg/ml). Once the technical parameters are determined and remain stable in an established process, our improved calibration method will make measuring molecular biological samples of unknown sequence composition more efficient, accurate and sample-saving than previous methods.

Eine neue Fluoreszenz-Fluktuations-spektroskopische Methode vereint die Vorzüge der Fluoreszenz-Korrelations-Spektroskopie mit denen helligkeitsbasierter Verfahren für hochpräzise Untersuchungen dynamischer biomolekularer Prozesse. Dieser Artikel stellt wesentliche Eigenschaften dieser neuen Methode vor.

Hintergrund: Fährschiffsunglücke auf der Ostsee; abhängig von der Position auf See hohe Todesrate oder vollständige Evaquierung ohne Opfer immer mit Verlust der Rettungsplattform. Methoden: Analyse von Ursachen und Risiken bei Schiffsbränden in Abhängigkeit von Besatzungsstärke,[for full text, please go to the a.m. URL], DAV 2011; 29. Jahrestagung der Deutschsprachigen Arbeitsgemeinschaft für Verbrennungsbehandlung

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International audience

International audience

International audience

OBJECTIVE: A growing body of literature is documenting the health effects of racial discrimination. The authors investigated the association between racial discrimination and alcohol-related behavior in a sample of urban transit operators. METHODS: Using data from a 1993-1995 cross-sectional study of transit operators in San Francisco, California, the authors analyzed responses to two sets of questions about racial discrimination; the first set focused on reaction to unfair treatment and the second on arenas, or domains, of discrimination. Alcohol-related variables were: number of drinks per month, heavy drinking, alcohol dependence, and negative consequences of alcohol consumption. RESULTS: Operators who reported five or more domains of discrimination drank an average of 13.4 more drinks per month than those who reported no domains of discrimination (P = 0.01). Similarly, they were more likely to be heavy drinkers (adjusted odds ratio [OR] = 2.16; 95% confidence interval [CI] 1.14, 4.09) and dependent on alcohol (adjusted OR = 2.02; 95% CI 1.08, 3.79) than operators who reported no domains of discrimination. The number of domains in which operators reported having experienced discrimination was not related to sex, age, household income, job seniority, or marital status, but varied significantly by educational level and race/ethnicity. CONCLUSIONS: Data from a sample of urban transit operators showed an association between the number of domains of discrimination and some alcohol-related outcomes, but not others.