Search results for "Spectroscopy"
showing 10 items of 10293 documents
Halloysite nanotubes filled with salicylic acid and sodium diclofenac: effects of vacuum pumping on loading and release properties
2021
AbstractIn this work, we investigated the effects of the vacuum pumping on both the loading efficiencies and the release kinetics of halloysite nanotubes filled with drug molecules dissolved in ethanol. As model drugs, salicylic acid and sodium diclofenac were selected. For comparison, the loading of the drug molecules was conducted on platy kaolinite to explore the key role of the hollow tubular morphology on the filling mechanism of halloysite. The effects of the pressure conditions used in the loading protocol were interpreted and discussed on the basis of the thermodynamic results provided by Knudsen thermogravimetry, which demonstrated the ethanol confinement inside the halloysite cavi…
Acute and repeated treatment with 5- or 9-PAHSA isomers does not improve glucose control in mice. Pflimlin et al.
2018
NMR spectra during chemical synthesis of 5- and 9-PAHSA described in Pflimlin et al., Cell Metabolism, 2018https://doi.org/10.1016/j.cmet.2018.05.028 THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOVE
Cytotoxic geranylflavonoids from Bonannia graeca
2011
The analysis of the aerial parts of Bonannia graeca led to the isolation and characterization of two new polar geranylated flavonoids (6 and 7). The structure elucidation was performed by extensive spectroscopic methods (1D and 2D NMR) and comparison with literature data. All natural flavonoids isolated from B. graeca (1–7) and some synthetic derivatives (8–11) were tested for cytotoxic activity against four human tumor cell lines. Preliminary structure-activity relationship correlations are discussed.
Use of linear discriminant analysis applied to vibrational spectroscopy data to characterize commercial varnishes employed for art purposes.
2007
An improvement of methodologies for characterising synthetic resins used in varnishes employed for art purposes has been suggested. Several kinds of standard of the most common polymeric resins (acrylic, vinyl, poly(vinyl alcohol), alkyd, cellulose nitrate, latex, polyester, polyurethane, epoxy, organosilicic, and ketonic) were analyzed by Fourier transform infrared (FTIR) spectroscopy. Synthetic resins characterization is based on the mathematical treatment of their whole spectrum, dividing it in 13 sections, avoiding the one-by-one interpretation of the absorption bands. The mathematical model takes as variables the maximal absorbance of each section, and each synthetic standard resin as …
Towards a fully synthetic MUC1-based anticancer vaccine: efficient conjugation of glycopeptides with mono-, di-, and tetravalent lipopeptides using c…
2011
Abstract The membrane-bound tumor-associated glycoprotein MUC1 is aberrantly glycosylated in cancer cells compared with normal cells, and is therefore considered an attractive target for cancer immunotherapy. However, tumor-associated glycopeptides from MUC1 do not elicit a sufficiently robust immune response. Therefore, antitumor vaccines were developed, which consist of MUC1 glycopeptides as the B epitopes and immune-stimulating toll-like receptor 2 (TLR 2) lipopeptide ligands. These fully synthetic vaccine candidates were prepared by solid-phase synthesis of the MUC1 glycopeptides. The Pam(3) Cys lipopeptide, also synthesized on solid-phase, was C-terminally coupled to oligovalent lysine…
Comparative study of several programs used in the potentiometric evaluation of equilibrium constants including an error sensitivity analysis
1989
Abstract The programs MINIQUAD, MINIPOT, SUPERQUAD and PHCONST are applied to the evaluation of the protonation constants of several hypothetical polyprotic substances using simulated titrations, and the precision and accuracy of the results are discussed and compared. When statistical weights are used the results are very similar, the accuracy being better with PHCONST. Error sensitivity analysis was used as a means of establishing the influence of a systematic error of an experimental variable on the accuracy of the determination. An algorithm for the accurate calculation of error sensitivities is proposed and checked. Error sensitivities can be used to make a choice between the various m…
The generalized H-point standard-additions method to determine analytes present in two different chemical forms in unknown matrix samples. Part I. Ge…
2000
This paper shows how the generalized H-point standard-additions method (GHPSAM) can be used to obtain the total concentration or concentrations of different chemical forms of an analyte when the matrix of the sample is completely unknown. The spectral regions where the interferent behaviour can be considered as linear are found and the analyte concentration free from bias error is estimated. This paper includes the already published features of the GHPSAM and a new modification of this method which allows the simultaneous determination of two chemical forms of an analyte in a sample.
Micromorphological approach to the systematics of Mediterranean Isoëtes species (Isoëtaceae, Lycopodiophyta): analysis of the megaspore surface
2012
Megaspore ornamentation is one of the few morphological characters used in the taxonomy of the genus Isoëtes. In the present work, we test the application of this character for distinguishing some Isoëtes species occurring in the Mediterranean: Isoëtes sicula, which according to some authors should be included as a variety in I. histrix, and the recently described I. todaroana, whose affinity with other taxa is currently unknown. Two additional species (I. duriei, I. velata) were also included in the analysis. The megaspores were studied using scanning electron microscopy combined with energy-dispersive X-ray spectroscopy and chemical treatment. In all species, the megaspore surface is cove…
The Activation Status of the TGF-β Transducer Smad2 Is Associated with a Reduced Survival in Gastrointestinal Cancers: A Systematic Review and Meta-A…
2019
Aberrant function of Smad2, a crucial member of transforming growth factor beta (TGF-β) signaling, is associated with the development of malignancies, particularly in the gastrointestinal district. However, little is known about its possible prognostic role in such tumor types. With the first meta-analysis on this topic, we demonstrated that the lack of the activated form of Smad2 (phosphor-Smad2 or pSmad2), which was meant to be the C-terminally phosphorylated form, showed a statistically significant association with an increased risk of all-cause mortality in patients with gastrointestinal cancers (RR, 1.58; 95% CI, 1.05–2.37, p = 0.029, I2 = 84%), also after having adjusted for potential…