Reference-independent wide field fluorescence lifetime measurements using Frequency-Domain (FD) technique based on phase and amplitude crossing point.

Fluorescence lifetime imaging microscopy (FLIM) is an essential tool in many scientific fields such as biology and medicine thanks to the known advantages of the fluorescence lifetime (FLT) over the classical fluorescence intensity (FI). However, the frequency domain (FD) FLIM technique suffers from its strong dependence on the reference and its compliance to the sample. In this paper, we suggest a new way to calculate the FLT by using the crossing point (CRPO) between the modulation and phase FLTs measured over several light emitting diode (LED) DC currents values instead of either method alone.

A mixed-ensemble model for hospital readmission.

Objective: A hospital readmission is defined as an admission to a hospital within a certain time frame, typically thirty days, following a previous discharge, either to the same or to a different hospital. Because most patients are not readmitted, the readmission classification problem is highly imbalanced.

Materials And Methods: We developed a hospital readmission predictive model, which enables controlling the tradeoff between reasoning transparency and predictive accuracy, by taking into account the unique characteristics of the learned database.

Time-averaged fluorescence intensity analysis in fluorescence fluctuation polarization sensitive experiments.

In fluorescence fluctuation polarization sensitive experiments, the limitations associated with detecting the rotational timescale are usually eliminated by applying fluorescence correlation spectroscopy analysis. In this paper, the variance of the time-averaged fluorescence intensity extracted from the second moment of the measured fluorescence intensity is analyzed in the short time limit, before fluctuations resulting from rotational diffusion average out. Since rotational correlation times of fluorescence molecules are typically much lower than the temporal resolution of the system, independently of the time bins used, averaging over an ensemble of time-averaged trajectories was performed in order to construct the time-averaged intensity distribution, thus improving the signal-to-noise ratio.

The influence of dead time related distortions on live cell fluorescence lifetime imaging (FLIM) experiments.

Recent developments in the field of fluorescence lifetime imaging microscopy (FLIM) techniques allow the use of high repetition rate light sources in live cell experiments. For light sources with a repetition rate of 20-100 MHz, the time-correlated single photon counting (TCSPC) FLIM systems suffer serious dead time related distortions, known as "inter-pulse pile-up". The objective of this paper is to present a new method to quantify the level of signal distortion in TCSPC FLIM experiments, in order to determine the most efficient laser repetition rate for different FLT ranges.

Photon efficiency optimization in time-correlated single photon counting technique for fluorescence lifetime imaging systems.

In time-correlated single photon counting (TCSPC) systems, the maximum signal throughput is limited by the occurrence of pile-up and other effects. In many biological applications that exhibit high levels of fluorescence intensity (FI), pile-up-related distortions yield serious distortions in the fluorescence lifetime (FLT) calculation as well as significant decrease in the signal-to-noise ratio (SNR). Recent developments that allow the use of high-repetition-rate light sources (in the range of 50-100 MHz) in fluorescence lifetime imaging (FLIM) experiments enable minimization of pile-up-related distortions.

Short time behavior of fluorescence intensity fluctuations in single molecule polarization sensitive experiments.

Recent developments in the field of single molecule orientation imaging have led us to devise a simple framework for analyzing fluorescence intensity fluctuations in single molecule polarization sensitive experiments. Based on the new framework, rotational dynamics of individual molecules are quantified, in this paper, from the short time behavior of the time averaged fluorescence intensity fluctuation trajectories. The suggested model can be applied in single molecule fluorescence fluctuations experiments to extract accurate expectation values of photon counts during very short integration time in which rotational diffusion is likely not to be averaged out.

Whole-object fluorescence lifetime setup for efficient non-imaging quantitative intracellular fluorophore measurements.

In the present study we introduce a Whole-Object Fluorescence Life Time (wo-FLT) measurement approach for ease and a relatively inexpensive method of tracing alterations in intracellular fluorophore distribution and in the physical-chemical features of the microenvironments hosting the fluorophore. Two common fluorophores, Rhodamine 123 and Acridine Orange, were used to stain U937 cells which were incubated, with and without either Carbonyl cyanide 3-chlorphenylhydrazon or the apoptosis inducer H(2)O(2). The wo-FLT, which is a non-imaging quantitative measurement, was able to detect several fluorescence decay components and corresponding weights in a single cell resolution.

Fractional Feynman-Kac equation for non-brownian functionals.

We derive backward and forward fractional Feynman-Kac equations for the distribution of functionals of the path of a particle undergoing anomalous diffusion. Fractional substantial derivatives introduced by Friedrich and co-workers [Phys. Rev.