New Aspects Regarding the Fluorescence Spectra of Melanin and Neuromelanin in Pigmented Human Tissue Concerning Hypoxia.

Melanin is a crucial pigment in melanomagenesis. Its fluorescence in human tissue is exceedingly weak but can be detected through advanced laser spectroscopy techniques. The spectral profile of melanin fluorescence distinctively varies among melanocytes, nevomelanocytes, and melanoma cells, with melanoma cells exhibiting a notably "red" fluorescence spectrum.

A phenomenological and quantitative view on the degradation of positive electrodes from spent lithium-ion batteries in humid atmosphere.

The present study deals with the phenomenological observation of the corrosion of the positive electrode foil of lithium-ion batteries containing LiNiCoMnO (NMC) as cathode material. Due to the presence of moisture, localized water accumulation is formed on the NMC surface. The water absorbed by the electrolyte reacts with the NMC under Li/H exchange and the resulting pH increase leads to dissolution of the carrier foil and characteristic salt-like blooms on the NMC surface.

Cross-section measurements of multilayer automotive paint samples using combined Raman spectroscopy and LIBS.

Multilayer automotive paint samples can be important evidence in forensic investigations but due to their inherent complexity it is a challenging task to analyze them. We herein present a method for a comprehensive chemical sample characterization based on the subsequent measurements of paint samples with Raman spectroscopy and laser induced breakdown spectroscopy (LIBS) at the same sampling points along the cross-sections of the paints. The method requires minimal sample preparation because the layers do not have to be separated.

From Melanocytes to Melanoma Cells: Characterization of the Malignant Transformation by Four Distinctly Different Melanin Fluorescence Spectra (Review).

The melanin fluorescence emitted by pigment cells of the human skin has been a central research topic for decades, because melanin, on the one hand, protects against (solar) radiation in the near-UV range, whereas on the other hand, melanocytes are the starting point for the malignant transformation into melanoma. Until recently, however, melanin fluorescence was not accessible in the context of conventional spectroscopy, because it is ultraweak and is overshadowed by the more intense so-called autofluorescence of endogenous fluorophores. The advent of a new method of laser spectroscopy has made this melanin fluorescence measurable in vivo.

UV-induced fluorescence spectra and lifetime determination for detection of leaf rust (Puccinia triticina) in susceptible and resistant wheat (Triticum aestivum) cultivars.

In modern agriculture, the use of cultivars that are resistant against specific stresses, e.g. pathogen infections, is an integral component.

Criteria for the multiple use of isolated perfused hearts in electrophysiological and metabolic experiments.

Both ethical and economic restrictions limit the availability of porcine hearts for in vitro perfusion experiments. Therefore, we tested the feasibility of multiple use of in vitro perfused working hearts for electrophysiological and metabolic investigations. Pig hearts (n=7) rejected for originally planned haemodynamic measurements because of exclusion criteria were perfused in a four-chamber working heart mode.

Fluorimetric characterisation of metabolic activity of ex vivo perfused pig hearts.

Autofluorescence of tissues and organs is an indicator of the physiological state of cells. The aim of the study was to investigate whether fluorimetric determination of the redox state of the ex vivo perfused pig heart can provide fast online detection of progressive changes in heart muscle tissue. Measurements on six organs perfused in a four-chamber working heart model were performed using a spectroscopic method exploiting the specific and different fluorescence lifetimes of intrinsic fluorophores such as NADH and flavins and providing a means of internal signal referencing.

Screening scheme based on measurement of fluorescence lifetime in the nanosecond domain.

The authors demonstrate that the fluorescence lifetime of certain fluorescent labels is a useful parameter to detect affinity binding between biotin and streptavidin, as well as between biotinylated bovine serum albumin and streptavidin. The assay is performed in a microplate format, and lifetimes are determined using dye laser-induced fluorescence. Four fluorescent labels are presented that undergo a significant change in their lifetime upon affinity binding.

Improved routine bio-medical and bio-analytical online fluorescence measurements using fluorescence lifetime resolution.

Fluorescence techniques are widely used as sensitive detection methods in bio-analytics. The use of the bio-physical parameter fluorescence lifetime additional to the spectral characteristics of fluorescence has the potential to improve fluorescence-related detection methods in terms of selectivity in signal recognition, robustness against disturbing influences, and the accessibility of novel bio-chemical process parameters. This article describes the technical set up of a time-resolving instrument with either a fixed time-gated detection principle for improved evaluation of tissue metabolism by an online monitoring of the tissue autofluorescence or a direct fluorescence lifetime detection principle for lifetime-based fluorescent assays.