Search results for "Coloring agents"
showing 10 items of 119 documents
Calix[4]arene-functionalized naphthalene and perylene imide dyes.
2002
[reaction: see text] Calix[4]arenes bearing one, two, or four 1,8-naphthyl imide groups at the wide rim and bis-calix[4]arenes connected via perylene-bisimide dye spacers have been synthesized. The low-temperature NMR spectrum of the tetranaphthylimide suggests, in agreement with a crystal structure, a C2-symmetrical pinched cone conformation stabilized via face-to-face pi-pi interactions between opposite naphthylimide groups. UV-vis and fluorescence studies have been carried out for the perylene bis-calix[4]arene dyes.
Uridine uptake inhibition as a cytotoxicity test for a human hepatoma cell line (HepG2 cells): comparison with the neutral red assay
2001
International audience; This study describes a sensitive microassay for measuring cytotoxicity based on the degree of inhibition of RNA synthesis in HepG2 cells. RNA synthesis is measured by the kinetic uptake of radiolabeled uridine. A large number of compounds were tested in a wide range of concentrations. The concentration required to induce 50% inhibition of HepG2 uridine uptake rates (IC50) was determined for each compound and used to rank its potency. These IC50s were compared with IC50s measured with the neutral red assay. 2-acetylaminofluorene, benzo[a]pyrene and methylnitrosourea were not cytotoxic in the neutral red assay. Uridine uptake was always inhibited at lower concentrations…
Metal-Organic Frameworks as Unique Platforms to Gain Insight of σ-Hole Interactions for the Removal of Organic Dyes from Aquatic Ecosystems.
2022
The combination of high crystallinity and rich host-guest chemistry in metal-organic frameworks (MOFs), have situated them in an advantageous position, with respect to traditional porous materials, to gain insight on specific weak noncovalent supramolecular interactions. In particular, sulfur σ-hole interactions are known to play a key role in the biological activity of living beings as well as on relevant molecular recognitions processes. However, so far, they have been barely explored. Here, we describe both how the combination of the intrinsic features of MOFs, especially the possibility of using single-crystal X-ray crystallography (SCXRD), can be an extremely valuable tool to gain insi…
Preparation methods to optimize the performance of sensor discs for fast chemiluminescence ozone analyzers.
2013
Fast ozone (O(3)) measurements (1-50 Hz) in the atmosphere are required for airborne studies and for the measurement of ground-based O(3) fluxes by the eddy covariance technique. Fast response analyzers, based on heterogeneous chemiluminescence, need dye coated sensor discs on which the chemiluminescence is generated. In this study, we present three new preparation methods for those sensor discs. Currently available sensor discs exhibit a fast temporal decay of sensitivity, resulting in short duty times which is troublesome for many field applications. To produce sensor discs that provide more stable signals over time, three dyes and nine energy transfer reagents were tested (as well as dif…
Insights into the Maya Blue technology: greenish pellets from the ancient city of La Blanca.
2011
Financial support is gratefully acknowledged from the MEC Projects CTQ2011-28079-CO3-01 and 02 which are also supported with ERDF funds. Research was conducted within the "Grupo de anlisis cientifico de bienes culturales y patrimoniales y estudios de ciencia de la conservacion" Microcluster of the University of Valencia Excellence Campus. The authors would like to thank Dr. Isabel Solana (SCSIE, UV), Dr. Jose Luis Moya Lopez, and Manuel Planes Insausti (Microscopy Service UPV) for their technical support.
Characterization of foxing stains in early twentieth century photographic and paper materials
2016
The subject of this present work is a group of nine historical pictures shot in Palermo by the Sicilian photographer E. Interguglielmi in 1912. They are nine matte-collodion prints mounted on the original cardboard supports and all of them show foxing stains affecting the paper surface. In order to characterise the chemical composition of the supports and investigate foxing spots, non-destructive and micro-destructive analysis were carried out. X-rays fluorescence (XRF) analysis was used to characterise the elemental composition of all the mounting boards, allowing a comparison between the foxing spots and non-affected areas. Laser-Induced Breakdown Spectroscopy was used to investigate the …
Infarct Size Measurement by Triphenyltetrazolium Chloride StainingVersus In VivoInjection of Propidium Iodide
1997
Infarct size delineation by triphenyltetrazolium chloride (TTC) staining is dependent on sufficient reperfusion. We therefore evaluated the possibility of using propidium iodide (PI), a reagent conventionally used in flow cytometry to fluorescently stain dead cells, for infarct size analysis after short periods of reperfusion. Forty-five rabbits were subjected to either 15 min, 2 h or 4.5 h of coronary artery occlusion without reperfusion, or to 15 min, 30 min and 2 h of coronary artery occlusion followed by 30 min, 1 h and 3 h of reperfusion. Fifteen min before terminating the experiment, PI was injected into the left atrium. Patent blue violet was used to delineate the area at risk. Follo…
Simultaneous confocal laser endomicroscopy and chromoendoscopy with topical cresyl violet
2009
Background Confocal laser endomicroscopy (CLE) has been shown to reliably predict histology during ongoing endoscopy. To unmask lesions for CLE, chromoendoscopy has been mandated. Usually fluorescein then serves as a contrast agent for CLE, but it does not allow direct nuclear visualization, must be injected, leads to a transient skin discoloration, and may have allergic side effects. Objective To establish a single topical dye, cresyl violet (CV), for simultaneous chromoendoscopy and in vivo CLE of the lower GI tract. Design Animal preclinical study, prospective clinical trial. Setting Mainz University Clinic (tertiary care center). Patients, Methods, and Interventions To establish the sta…
Neuronal ceroid-lipofuscinosis--late-infantile or Jansky-Bielschowsky type--revisited.
1996
Among the now eight genetic types of neuronal ceroid-lipofuscinoses (NCL), CLN1 to CLN8, CLN2 is considered classic late-infantile NCL. It was originally described by Janský in a family of eight children with four of them affected [Janský J (1908) Sborn Lek 13:165-196] and, subsequently, by Bielschowsky in a family of three children each of whom was affected, and, hence, termed Janský-Bielschowsky type of NCL. Earlier, archival studies of Bielschowsky's original post-mortem tissue blocks had documented accumulation of autofluorescent lipopigments with a curvilinear ultrastructure. In a subsequent study, described here, immunohistochemical absence of the CLN2-related lysosomal enzyme tripept…
Standardized staining methods: Feulgen-Rossenbeck reaction for desoxyribonucleic acid and periodic acid-Schiff (PAS) procedure
2002
A project group working under the European Confederation of Laboratory Medicine (ECLM) presents recommendations for standardized procedures for the Feulgen-Rossenbeck-Schiff and the periodic acid-Schiff (PAS) reactions on cytological and histological material. The advantages and disadvantages of such standardized procedures are presented here in a preamble. Both users and manufacturers are encouraged to give their opinions with a view to achieving consensus on these procedures and on how further work on these lines may proceed.