Investigating electric field induced molecular distortions in polypropylene using Raman spectroscopy

Polymeric electric insulators are an integral part of many electronic circuits and systems. Changes induced by an electric field can affect various mechanisms; including electrical polarisation and electromechanical properties. Changes in the dielectric material can be tracked using spectroscopic methods. This study has shown that analysing polypropylene under electric field stress using Raman spectroscopy in combination with principal component analysis allows small changes in the non-crystalline phase to be identified. We have observed that for polypropylene, vibrational motion and changes in conformation occur mostly within the tie molecules connecting the overall cluster network. Amorphous molecular chains in the spherulites were also found to orient and form into a smectic mesophase. These electromechanical changes at the micro- and macromolecular level were found to be generally reversible once the stress is removed. However, with increased aging, these changes may lead to adverse structural changes and thus, in the future, this information may be used to inform faults and defect detection within polymeric dielectric materials

A study of in vitro metabolism and cytotoxicity of mephedrone and methoxetamine in human and pig liver models using GC/MS and LC/MS analyses

In the current study, the metabolism of two novel psychoactive substances (NPS), mephedrone and methoxetamine (MXE), was studied in vitro using pig liver microsomes to determine potential metabolites by liquid chromatography mass spectrometry (LC-MS). Later, in vitro studies were performed using HepaRG™ Cells to determine the human metabolites of these drugs using gas-chromatography mass spectrometry (GC-MS). The aim of the study was to be able to detect metabolites from the metabolic mixture in the human cell lines using a GC-MS, since this is a more readily available technique within forensic laboratories Microsomes were prepared through a conventional ultracentrifugation method and incubated under optimised conditions with the drugs for 3 h. Subsequently, the samples were investigated using LC-MS. A similar methodology was then applied for the HepaRG™ Cell and GC-MS conditions were optimised by using N,O-Bis(trimethylsilyl)trifluoroacetamide (BSTFA) as a derivatisation agent. The analysis showed two molecules from a successful in vitro metabolism, namely hydroxytoly-mephedrone and nor-dihydro mephedrone. For Methoxetamine (MXE), two metabolites are presented, produced by the O-demethylation and reduction of the ketone moiety to the corresponding alcohol, respectively. Using the human HepaRG™ cells, only nor-dihydro mephedrone could be identified by GC-MS. Since hydroxytoly-mephedrone and the MXE metabolites are more polar, it is suggested that GC-MS even with derivatisation may not be suitable. In addition, cytotoxicity was studied utilizing HepaRG™ cell lines. The drugs show cytotoxic effects causing in vitro cell death, within the specified range of EC50 0.3211 mM (79 μg/mL) and 0.6297 mM for mephedrone and MXE, respectively. These drugs were able to cause 73-84% cell death

Belagerte Moderne: Krieg und Kommune in der französischen Druckgraphik 1870/71 ; Begleitheft zur Ausstellung

Der Deutsch-Französische Krieg und die gewaltsamen Auseinandersetzungen um die Pariser Kommune stellen einen denkbar scharfen Kontrast zum kulturellen Leben der modernen Metropole Paris in den Jahren vor 1870 dar. Die 1860er Jahre waren auch in den bildenden Künsten von einem produktiven Aufbruch gekennzeichnet: Édouard Manet hatte mit ersten Skandalen in Ausstellungen auf sich aufmerksam gemacht; Maler wie Claude Monet und Camille Pissarro begannen damit, den Impressionismus herauszubilden; und eine Reihe von ambitionierten Druckgraphikern hatte die Radierung als anspruchsvolles und durchaus modernes Bildmedium wiederbelebt. Während Krieg und Kommune in der offiziellen Kunst und im Impressionismus vergleichsweise wenige Spuren hinterlassen haben, lassen sich die einschneidenden Ereignisse der Jahre 1870 und 1871 in der Druckgraphik gut nachvollziehen. Radierungen von Adolphe Martial Potémont, Maxime Lalanne oder François Pierdon führen vor Augen, wie die Künstler mit ihren zuvor entwickelten künstlerischen Mitteln auf die radikal veränderte Situation zu reagieren versuchten. Ausstellung und Begleitheft stellen ausgewählte Druckgraphiken von französischen Künstlern ins Zentrum, um einen etwas anderen Blick auf den Deutsch-Französischen Krieg und die Kommune zu richten

Evaluating Residual Compressive strength of Post-fire Concrete using Raman 3 Spectroscopy

Cement and water within the concrete mass create a hydrated phase which acts as the glue for holding the sand and coarse aggregates in place to develop a strong construction material. The most important phase within the cement matrix is that of calcium silicate hydrate (CSH), which is largely responsible for the concrete strength. Decomposition of the CSH phase due to high temperatures will affect compressive strength of the concrete. Raman bands at 1083, 709 and 276 cm-1 , which are representative of the CaCO3 and CSH presence 18 in the concrete matrix phases can be used to assess changes in compressive strength as a result of thermal decomposition. The ratio between 1083/709 cm-1 bands was calculated and correlated to 20 the compression strength of the concrete. The results show there is a rapid decline in strength around a critical peak ratio of 8.78 and a residual compressive strength of 0.62, closely following a polynomial curve. The tool developed here allows an indirect evaluation of the temperature the concrete has been exposed to by studying the band. A case study from a fire scene taken from a warehouse in Kingston (Jamaica) is also presented 25 with the conclusion and results compared. The study showed that Raman spectroscopy has the 26 potential to provide in-situ non-destructive testing of fire damaged concrete rapidly and accuratel

The use of Raman spectroscopy to monitor phase changes in concrete following high temperature exposure

Concrete is one of the most widely used construction materials, having excellent mechanical properties, but may fail in a catastrophic manner post fire. In this study, we present non-destructive Raman testing of concrete walls post fire to track temperature exposure based on the decomposition of the calcium silicate hydrate (CSH) phase. The use of Raman spectroscopy is contrasted with X-ray diffraction to demonstrate its competence in evaluating thermal damage to concrete. It was found that Raman spectroscopy was more adept at identifying the hydrated phases than XRD. Principal component analysis was applied to the Raman data to demonstrate the ability of Raman spectroscopy to distinguish concrete exposed to different temperatures. The decomposition of Calcium silicate hydrate could be followed by Raman monitoring the shifts at 1081, 709 and 278 cm−1. At the highest temperature in this study (950 °C) Raman spectra showed the disappearance of these bands with formation of a new one at 1007 cm−1 attributed to the formation of gehlenite following the matrix decomposition

Prognostic Value of Tumour-Infiltrating Lymphocytes in an Unselected Cohort of Breast Cancer Patients

Tumour-infiltrating lymphocytes (TILs) are considered to have prognostic and predictive value for patients with early breast cancer. We examined 1166 breast cancer patients from a prospective, multicentre cohort (Prognostic Assessment in Routine Application (PiA), n = 1270, NCT 01592825) following recommendations from the International TILs Working Group. TIL quantification was performed using predefined groups and as a continuous variable in 10% increments. The primary objective was the distribution of TILs in different breast cancer types. The second objective was the association with the recurrence-free interval (RFI) and overall survival (OS). Stromal infiltration with more than 60% TILs appeared in 2% of hormone receptor (HR)-positive and HER2-negative tumours, in 9.8% of HER2-positive tumours (any HR) and 19.4% of triple-negative breast cancers (TNBCs). Each 10% increment was associated with an improvement in the prognosis in HER2-positive samples (RFI, hazard ratio 0.773, 95% CI 0.587–1.017; OS, hazard ratio 0.700, 95% CI 0.523–0.937). When defining exploratory cut-offs for TILs, the use of a 30% threshold for the HR-positive and HER2-negative group, a 20% threshold for the HER2 group and a 60% threshold for the TNBC group appeared to be the most suitable. TILs bore prognostic value, especially in HER2-positive breast cancer. For clinical use, additional research on the components of immune infiltration might be reasonable