66 results match your criteria: "UniversitaetsstraSSe 5[Affiliation]"

Investigation of the Cholesterol Biosynthesis by Heart-Cut Liquid Chromatography and Mass Spectrometric Detection.

J Chromatogr A

December 2024

Applied Analytical Chemistry, University of Duisburg-Essen, Universitaetsstrasse 5, 45141 Essen, Germany. Electronic address:

Article Synopsis
  • Cholesterol is crucial for cell function, playing roles in membrane stability and signaling, but identifying and quantifying its biosynthesis intermediates is challenging due to structural similarities and concentration differences.
  • A new heart-cut liquid chromatography method was developed, tested on 38 different columns, and successfully separates all sterol biosynthesis intermediates with low detection limits.
  • The method was applied to lung carcinoma cells treated with statins, revealing its effectiveness in detecting biological responses and providing a strong approach to studying cholesterol's role in disease.
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Cracking the non-verbal "code" of human emotions has been a chief interest of generations of scientists. Yet, despite much effort, a dictionary that clearly maps non-verbal behaviours onto meaning remains elusive. We suggest this is due to an over-reliance on language-related concepts and an under-appreciation of the evolutionary context in which a given non-verbal behaviour emerged.

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In mass spectrometry imaging (MSI), ion suppression can lead to a misinterpretation of results. Particularly phospholipids, most of which exhibit high gas-phase basicity (GB), are known to suppress the detection of metabolites and drugs. This study was initiated by the observation that the signal of an herbicide, i.

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The Why and How of Ultrasmall Nanoparticles.

Acc Chem Res

December 2023

UCD School of Chemistry, Science Centre South, University College Dublin, Belfield, Dublin 4, Ireland.

In this Account, we describe our research into ultrasmall nanoparticles, including their unique properties, and outline some of the new opportunities they offer. We will summarize our perspective on the current state of the field and highlight what we see as key questions that remain to be solved. First, there are several nanostructure size-scale regimes, with qualitatively distinct functional biological attributes.

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Non-destructive, solvent-free quantification of wood preservatives in wood flour and wooden objects using GC-DTIMS.

Talanta

February 2024

Department of Analytical Chemistry, University of Duisburg-Essen, Universitaetsstraße 5, Essen, 45141, North Rhine-Westphalia, Germany. Electronic address:

Qualitative and quantitative on-site detection methods for wood preservatives are of high value for the recycling industry and the occupational health and safety. Wood preservatives revealed as toxic to human and environment after decades of use. For the detection of contaminated wood and for processing of matured timber to particle boards a versatile detection method is needed.

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Pesticides are major agricultural stressors for freshwater species. Exposure to pesticides can disrupt the biotic integrity of freshwater ecosystems and impair associated ecosystem functions. Unfortunately, physiological mechanisms through which pesticides affect aquatic organisms are largely unknown.

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Potentiating Tweezer Affinity to a Protein Interface with Sequence-Defined Macromolecules on Nanoparticles.

Biomacromolecules

August 2023

Department for Organic Chemistry and Macromolecular Chemistry, Heinrich Heine University Duesseldorf, Universitaetsstraße 1, Duesseldorf 40225, Germany.

Survivin, a well-known member of the inhibitor of apoptosis protein family, is upregulated in many cancer cells, which is associated with resistance to chemotherapy. To circumvent this, inhibitors are currently being developed to interfere with the nuclear export of survivin by targeting its protein-protein interaction (PPI) with the export receptor CRM1. Here, we combine for the first time a supramolecular tweezer motif, sequence-defined macromolecular scaffolds, and ultrasmall Au nanoparticles (us-AuNPs) to tailor a high avidity inhibitor targeting the survivin-CRM1 interaction.

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Background: Freshwaters are exposed to multiple anthropogenic stressors, leading to habitat degradation and biodiversity decline. In particular, agricultural stressors are known to result in decreased abundances and community shifts towards more tolerant taxa. However, the combined effects of stressors are difficult to predict as they can interact in complex ways, leading to enhanced (synergistic) or decreased (antagonistic) response patterns.

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A switchable DNA origami/plasmonic hybrid device with a precisely tuneable DNA-free interparticle gap.

Chem Commun (Camb)

December 2022

Department of Chemistry, Center for Nanointegration Duisburg-Essen (CENIDE) and Center for Medical Biotechnology (ZMB), University of Duisburg-Essen, Universitaetsstraße 5, 45141 Essen, Germany.

We here show a reconfigurable DNA/plasmonic nanodevice with a precisely tunable and DNA-free interparticle gap. The nanodevice comprises two DNA boxes for the size-selective incorporation of nanoparticles in a face-to-face orientation and an underlying switchable DNA platform for the controlled and reversible adjustment of the interparticle distance.

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Incorporation of Fluoride into Human Teeth after Immersion in Fluoride-Containing Solutions.

Dent J (Basel)

August 2022

Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Universitaetsstrasse 5-7, 45117 Essen, Germany.

Toothpastes and mouth rinses contain fluoride as a protective agent against caries. The aim of this study was to determine the degree of fluoride-uptake by human tooth mineral during immersion into fluoride-containing aqueous solutions as different pH. Human teeth were immersed in fluoride-containing solutions to assess the extent of fluoride incorporation into tooth enamel.

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The Peptide/Antibody-Based Surface Decoration of Calcium Phosphate Nanoparticles Carrying siRNA Influences the p65 NF-κB Protein Expression in Inflamed Cells In Vitro.

Biomedicines

July 2022

Department of Experimental Radiology, Institute of Diagnostic and Interventional Radiology, Jena University Hospital, Friedrich Schiller University Jena, Am Klinikum 1, D-07740 Jena, Germany.

Earlier studies with nanoparticles carrying siRNA were restricted to investigating the inhibition of target-specific protein expression, while almost ignoring effects related to the nanoparticle composition. Here, we demonstrate how the design and surface decoration of nanoparticles impact the p65 nuclear factor-kappa B (NF-κB) protein expression in inflamed leucocytes and endothelial cells in vitro. We prepared silica-coated calcium phosphate nanoparticles carrying encapsulated siRNA against p65 NF-κB and surface-decorated with peptides or antibodies.

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Bile acids are a group of steroid compounds essential for lipid digestion. However, when bile acids are refluxed into the stomach and the esophagus, during the so called duodenogastroesophageal reflux, they can have a detrimental effect on the esophageal epithelium and cause pathological changes of esophageal tissue, e.g.

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Uptake of Functional Ultrasmall Gold Nanoparticles in 3D Gut Cell Models.

Small

August 2022

Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Universitaetsstrasse 5-7, 45117, Essen, Germany.

Ultrasmall gold nanoparticles (2 nm) easily penetrate the membranes of intestinal murine epithelial cells (MODE-K) and colorectal cancer cells (CT-26). They are also taken up by 3D spheroids (400 µm) of these cell types and primary gut organoids (500 µm). In contrast, dissolved dyes are not taken up by any of these cells or 3D structures.

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Ultrafast cold-brewing of coffee by picosecond-pulsed laser extraction.

NPJ Sci Food

April 2022

Technical Chemistry I and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Universitaetsstrasse 7, 45141, Essen, Germany.

Coffee is typically brewed by extracting roasted and milled beans with hot water, but alternative methods such as cold brewing became increasingly popular over the past years. Cold-brewed coffee is attributed to health benefits, fewer acids, and bitter substances. But the preparation of cold brew typically needs several hours or even days.

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Comparative study for analysis of carbohydrates in biological samples.

Anal Bioanal Chem

March 2022

Applied Analytical Chemistry, University of Duisburg-Essen, Universitaetsstrasse 5, 45141, Essen, Germany.

This work presents a comparative study for the analysis of carbohydrates for four common chromatographic methods, each coupled to mass spectrometry. Supercritical fluid chromatography (SFC), hydrophilic interaction liquid chromatography (HILIC), reversed-phase liquid chromatography (RP-LC) and gas chromatography (GC) with detection by triple quadrupole mass spectrometer (QqQ-MS) are compared. It is shown that gas chromatography and reversed-phase liquid chromatography, each after derivatisation, are superior to the other two methods in terms of separation performance.

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Hearing in subterranean rodents exhibits numerous peculiarities, including low sensitivity and restriction to a narrow range of comparatively low frequencies. Past studies provided two conflicting hypotheses explaining how these derived traits evolved: structural degeneration and adaptive specialization. To further elucidate this issue, we recorded auditory brainstem responses from three species of social subterranean rodents that differ in the degree of specialization to the underground habitat: the naked mole-rat (Heterocephalus glaber) and the Mashona mole-rat (Fukomys darlingi), which represent the ancient lineage of African mole-rats (Bathyergidae), and the coruro (Spalacopus cyanus), a South American rodent (Octodontidae) that adopted a subterranean lifestyle in more recent geological time.

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Pigmentation patterns of the visible part of the eyeball, encompassing the iris and portions of the sclera, have been discussed to be linked to social cognition in primates. The cooperative eye hypothesis suggests the white sclera of humans to be a derived adaptive trait that enhances eye-mediated communication. Here, we provide a comparative analysis of ocular pigmentation patterns in 15 species of hominoids (humans, great apes & gibbons) that show marked differences in social cognition and quantify scleral exposure at the genus level.

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Metal-Ligand Interface and Internal Structure of Ultrasmall Silver Nanoparticles (2 nm).

J Phys Chem B

June 2021

Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitaetsstrasse 5-7, 45117 Essen, Germany.

Ultrasmall silver nanoparticles were prepared by reduction with NaBH and surface-terminated with glutathione (GSH). The particles had a solid core diameter of 2 nm as shown by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). NMR-DOSY gave a hydrodynamic diameter of 2 to 2.

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The anthropogenic entry of organic micropollutants into the aquatic environment leads to a potential risk for drinking water resources and the drinking water itself. Therefore, sensitive screening analysis methods are needed to monitor the raw and drinking water quality continuously. Non-target screening analysis has been shown to allow for a more comprehensive investigation of drinking water processes compared to target analysis alone.

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Development of an inverse low-temperature plasma ionization source for liquid chromatography/mass spectrometry.

Rapid Commun Mass Spectrom

May 2021

Department of Applied Analytical Chemistry, University of Duisburg-Essen, Universitaetsstrasse 5, Essen, 45141, Germany.

Rationale: An argon inverse low-temperature plasma (iLTP) ionization source for liquid chromatography/tandem mass spectrometry was developed. The iLTP is constructed from simple chromatographic supply materials and is implemented into an atmospheric pressure chemical ionization (APCI) source replacing the APCI discharge needle electrode. The newly developed ion source was coupled to an ultra-high-performance liquid chromatography (UHPLC) system.

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Bioindication has become an indispensable part of water quality monitoring in most countries of the world, with the presence and abundance of bioindicator taxa, mostly multicellular eukaryotes, used for biotic indices. In contrast, microbes (bacteria, archaea and protists) are seldom used as bioindicators in routine assessments, although they have been recognized for their importance in environmental processes. Recently, the use of molecular methods has revealed unexpected diversity within known functional groups and novel metabolic pathways that are particularly important in energy and nutrient cycling.

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Chemical characterization of eight herbal liqueurs by means of liquid chromatography coupled with ion mobility quadrupole time-of-flight mass spectrometry.

J Chromatogr A

November 2020

Applied Analytical Chemistry, University of Duisburg-Essen, Universitaetsstrasse 5, Essen 45141, Germany; Teaching and Research Center for Separation, University of Duisburg-Essen, Universitaetsstrasse 5, Essen 45141, Germany. Electronic address:

Herbal liqueurs are a large group of diverse alcoholic beverages with an ancient tradition produced by maceration of various herbs and spices and are commonly drunken before or after a meal to aid in the digestion because of their potential functional properties. In the presented work, eight different commercial herbal liqueurs were investigated with regard to their composition of phenolic compounds by liquid chromatography ion mobility quadrupole time-of-flight mass spectrometry (LC-IM-QTOF-MS). This multidimensional analytical platform uses all-ion fragmentation for a deep coverage of the foodome.

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Development of a fast-switching dual (ESI/APCI) ionization source for liquid chromatography/mass spectrometry.

Rapid Commun Mass Spectrom

September 2020

Applied Analytical Chemistry, University of Duisburg-Essen, Universitaetsstrasse 5, Essen, 45141, Germany.

Rationale: High-throughput liquid chromatography/mass spectrometry (LC/MS) is an increasing topic in analytical chemistry. Especially the idle time of a mass spectrometer should be reduced for an efficient and cost-saving use. Therefore, a fast-switching dual ion source was developed, which uses the most important ionization techniques at atmospheric pressure, electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI), with one or more LC systems.

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Phosphorylation of the acyl-CoA binding pocket of the FadR transcription regulator in Sulfolobus acidocaldarius.

Biochimie

August 2020

Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050, Brussels, Belgium. Electronic address:

The archaeal model organism Sulfolobus acidocaldarius possesses a TetR-like transcription factor that represses a 30-kb gene cluster encoding fatty acid metabolism enzymes. Interaction of this regulator, FadR, with acyl-CoA molecules causes a DNA dissociation, which may lead to a derepression of the gene cluster. Previously, a phosphoproteome analysis revealed the phosphorylation of three consecutive amino acids in the acyl-CoA ligand binding pocket.

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Reversed-phase liquid chromatography (RPLC) used for water analysis is not ideal for the analysis of highly polar and ionic contaminants because of low retention. Capillary electrophoresis (CE), on the other hand, is perfectly suited for the separation of ionic compounds but rarely applied in environmental analysis due to the weak concentration sensitivity when coupled to mass spectrometry (MS). However, novel interface designs and MS technology strongly improve the sensitivity.

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