Search results for "trace"
showing 10 items of 3218 documents
Determination of trimethoprim by the linear absorbances method
1995
The determination of trimethoprim in the presence of dyphylline, proxyphylline, theophylline and caffeine by the linear absorbances method is described. Collinear couples of wavelengths, for the interfering dyphylline-proxyphylline-theophylline-caffeine system (in H2SO4, 0.05 mol/L), are provided in order to allow the determination of the analyte in the presence of these interfering substances.
Inkjet printing Ag nanoparticles for SERS hot spots
2018
A novel inkjet printing based approach is developed for the fabrication of a customizable platform on glass substrates allowing for surface enhanced Raman spectroscopy (SERS) detection of analytes up to single hot spots generated by the spontaneous aggregation of Ag nanoparticles (Ag NPs) in pL scale droplets. After drying the printed droplets under ambient conditions, trace amounts of the analyte can be detected by SERS given the proximity to NP hot spots. By employing alizarin (10-5M) as a model system and scaling the ink droplet volume from 1 nL to 10 pL, the absolute quantity of hot spots has been derived in the printed droplets allowing detecting up to a few molecules in proximity to i…
Trace elemental composition of curry by inductively coupled plasma optical emission spectrometry (ICP-OES)
2008
A methodology based on inductively coupled plasma optical emission spectrometry (ICP-OES) after microwave-assisted acid digestion was developed to determine the content of traces elements in curry samples from the Spanish market. The methodology was validated in terms of accuracy by the analysis of citrus and tomato leaf reference materials achieving comparable results with the certified values. The trace metal content of curry samples was compared with data available from previously published reports concerning Indian samples, especially in terms of heavy metal composition, in order to guarantee the quality of the commercially available spices in the European countries. Values found for th…
Evaluation of Thin Film Microextraction for trace elemental analysis of liquid samples using LIBS detection
2021
An analytical methodology based in the combination of Thin Film Microextraction with Laser-induced Breakdown Spectroscopy (TFME-LIBS) was investigated, for the first time, for detection of Cu, Cr, Ni and Pb in aqueous solutions. In this methodology, the analytes were extracted in a thin film of adsorbent material deposited on a solid support, which was introduced in the sample to analyse. After extraction, the analytes retained in the adsorbent were analysed by LIBS. In order to obtain adsorbent films useful for the microextraction step, two different experimental procedures for film generation, denoted as Drop Casting Deposition and Mould Deposition, were evaluated. In both cases, graphene…
Inhibition of Histone Deacetylase Activity in Human Endometrial Stromal Cells Promotes Extracellular Matrix Remodelling and Limits Embryo Invasion
2011
Invasion of the trophoblast into the maternal decidua is regulated by both the trophoectoderm and the endometrial stroma, and entails the action of tissue remodeling enzymes. Trophoblast invasion requires the action of metalloproteinases (MMPs) to degrade extracellular matrix (ECM) proteins and in turn, decidual cells express tissue inhibitors of MMPs (TIMPs). The balance between these promoting and restraining factors is a key event for the successful outcome of pregnancy. Gene expression is post-transcriptionally regulated by histone deacetylases (HDACs) that unpacks condensed chromatin activating gene expression. In this study we analyze the effect of histone acetylation on the expressio…
Common genetic denominators for Ca++-based skeleton in Metazoa: role of osteoclast-stimulating factor and of carbonic anhydrase in a calcareous spong…
2012
Calcium-based matrices serve predominantly as inorganic, hard skeletal systems in Metazoa from calcareous sponges [phylum Porifera; class Calcarea] to proto- and deuterostomian multicellular animals. The calcareous sponges form their skeletal elements, the spicules, from amorphous calcium carbonate (ACC). Treatment of spicules from Sycon raphanus with sodium hypochlorite (NaOCl) results in the disintegration of the ACC in those skeletal elements. Until now a distinct protein/enzyme involved in ACC metabolism could not been identified in those animals. We applied the technique of phage display combinatorial libraries to identify oligopeptides that bind to NaOCl-treated spicules: those oligop…
Intracellul�re Verteilung von Choriongonadotropin in der Placenta des Menschen
1954
1. Reife, frische Placenten wurden in ihre einzelnen Zellelemente (Zellkerne, Mitochondrien, Mikrosomen + Cytoplasma) getrennt und auf chemische Zusammensetzung und Choriongonadotropingehalt nach dem Krotentest untersucht.
Neutrophil extracellular traps arm DC vaccination against NPM-mutant myeloproliferation
2021
AbstractNeutrophil extracellular traps (NET) are web-like chromatin structures composed by dsDNA and histones, decorated with anti-microbial proteins. Their interaction with dendritic cells (DC) allows DC activation and maturation toward presentation of NET-associated antigens. Differently from other types of cell death that imply protein denaturation, NETosis preserves the proteins localized onto the DNA threads for proper enzymatic activity and conformational status, including immunogenic epitopes. Besides neutrophils, leukemic cells can release extracellular traps displaying leukemia-associated antigens, prototypically mutant nucleophosmin (NPMc+) that upon mutation translocates from nuc…
The enemy in you: the interdependency of the localisation and antigenicity of proteins
2009
The subcellular localisation of protein components should be important for their antigenicity. This assumption is derived from the concept of MHC restriction, where CD4 and CD8 T lymphocytes can only interact with MHC II and MHC I surface receptors, respectively. If this mechanism applies, however, then intracellular components should have immunogenic effects mediated by MHC II and CD4 T lymphocytes as soon as they enter the extracellular space. Conversely, extracellular components should generate an immune response that is mediated by MHC I and CD8 lymphocytes when they breach the intracellular space and when they exceed a critical concentration. In this study, these hypotheses were invest…
Granulysin‐Dependent Killing of Intracellular and ExtracellularMycobacterium tuberculosisby Vγ9/Vδ2 T Lymphocytes
2001
Contribution of Vgamma9/Vdelta2 T lymphocytes to immune protection against Mycobacterium tuberculosis is still a matter of debate. It was reported earlier that Vgamma9/Vdelta2 T lymphocytes kill macrophages harboring live M. tuberculosis through a granule-dependent mechanism that results in killing of intracellular bacilli. This study found that Vgamma9/Vdelta2 T lymphocytes reduce the viability of both extracellular and intracellular M. tuberculosis. Granulysin and perforin, both detected in Vgamma9/Vdelta2 T lymphocytes, play a major role, which indicates that Vgamma9/Vdelta2 T lymphocytes directly contribute to a protective host response against M. tuberculosis infection.