Formation of phosphonate coatings for improved chemical stability of upconverting nanoparticles under physiological conditions

2021 ◽  
Author(s):  
Maša Vozlič ◽  
Tina Černič ◽  
Sašo Gyergyek ◽  
Boris Majaron ◽  
Maja Ponikvar-Svet ◽  
...  
Keyword(s):  
Chemical Stability ◽  
Synthesis Temperature ◽  
Physiological Conditions ◽  
Coating Synthesis

The protection of phosphonate coatings against the dissolution of upconverting nanoparticles under physiological conditions was significantly improved by increasing the coating-synthesis temperature to 80 °C.

Chemical Stability of Si-SiC Nanostructures under Physiological Conditions

2017 ◽  
Vol 897 ◽  
pp. 638-641 ◽  
Author(s):  
Romain Bange ◽  
Edwige Bano ◽  
Laetitia Rapenne ◽  
Sébastien Labau ◽  
Bernard Pelissier ◽  
...  
Keyword(s):  
Chemical Stability ◽  
Silicon Nanowires ◽  
Direct Detection ◽  
Chemical Species ◽  
High Sensitivity ◽  
Biological Molecules ◽  
Physiological Conditions ◽  
Long Term Stability ◽  
Detection Of Biomolecules

The fast and direct detection of small quantities of biological and chemical species is of key importance for numerous biomedical applications. Extensive research has been conducted on nanoelectronic devices that can perform such detection with high sensitivity using silicon nanowires and nanostructures. However, it was recently demonstrated that Si material suffers a lack of long-term stability in physiological environments at nanometer scale [1,2], and is hence not suited for in situ sensing of biological molecules. The results presented here are two important steps toward the realization of core-shell Si-SiC NWFETs for the detection of biomolecules in liquid media. First, we show that SiC NWs exhibit higher chemical stability than Si NWs under physiological conditions. Second, we present the successful carburation of a thin film of Si resulting in a 3.6 nm thin SiC layer.

Biolabeling with cobaltocinium tags

2018 ◽  
Vol 73 (11) ◽  
pp. 781-791
Author(s):  
Susanne Müller-Bomke ◽  
Michael Sperling ◽  
Heiko Hayen ◽  
Uwe Karst
Keyword(s):  
Liquid Chromatography ◽  
Redox Potential ◽  
Chemical Stability ◽  
Spectroscopic Properties ◽  
Mass Spectrometric ◽  
Mass Spectrometric Detection ◽  
Cysteine Residues ◽  
Reaction Conditions ◽  
Physiological Conditions ◽  
Derivatizing Agent

AbstractA label for amino and thiol functionalities of peptides and proteins based on the activated cobaltocinium hexafluorophosphate succinimide ester (CoS) is presented. Despite the known selectivity of a succinimide ester towards amines, CoS also modifies cysteine residues under the same reaction conditions. The derivatized biomolecules were investigated using liquid chromatography with subsequent electrospray-mass spectrometric detection (LC/ESI-MS). In combination with their remarkable stability under physiological conditions, easy handling and good spectroscopic properties, cobaltocinium ions provide all requirements for a powerful labeling reagent. Furthermore, in direct comparison to the isoelectronic well-established ferrocene reagents, the higher redox potential and the chemical stability of the cobaltocinium moiety add to the benefits as a derivatizing agent for bioanalysis.

scholarly journals PRELIMINARY DETERMINATION OF HYDROLYTIC STABILITY OF A PYRROLE-BASED HYDRAZIDE AND ITS HYDRAZONE

2018 ◽  
Vol 6 ◽  
pp. 1192-1198 ◽  
Author(s):  
Diana Tzankova ◽  
Lily Peikova ◽  
Maya Georgieva
Keyword(s):  
Chemical Stability ◽  
Hydrolytic Stability ◽  
Acidic Ph ◽  
Physiological Conditions ◽  
Ph Values ◽  
Blood Ph ◽  
Stomach Ph ◽  
Physiological Values ◽  
Preliminary Determination

A validated UV/VIS method for preliminary determination of the chemical stability and stability in close to physiological conditions of a model pyrrole hydrazide and its corresponding derivative, bearing susceptible to hydrolysis hydrazone group was developed. The evaluated substances were subjected to the influence of a variety of pH medias, representing the main physiological values of 37°C and corresponding pH values in the stomach (pH 2.0), blood (pH 7.4) and small intestine (pH 9.0). The chemical stability at strong alkali media of pH 13.0 was also evaluated. The hydrazide was found to be stable at all investigated conditions. The tested hydrazone was determined to be stable at pH of 7.4 and a temperature of 37°C and susceptible to hydrolysis at strong acidic (pH 2.0) and moderate alkali (pH 9.0) media at the same temperature. In addition, a decrease in the absorption at strong alkali media (pH 13.0) was observed, showing the compounds instability under these conditions.

Cu2ZnSnS4 thin films: spin coating synthesis and photoelectrochemistry

RSC Advances ◽  
2014 ◽  
Vol 4 (41) ◽  
pp. 21318-21324 ◽  
Author(s):  
Jing Wang ◽  
Peng Zhang ◽  
Xuefeng Song ◽  
Lian Gao
Keyword(s):  
Thin Films ◽  
Surface Modification ◽  
Chemical Stability ◽  
Spin Coating ◽  
Spin Coating Method ◽  
Coating Method ◽  
Coating Synthesis ◽  
Czts Thin Films

CZTS thin films possessing outstanding photoelectrochemical (PEC) efficiency and chemical stability have been prepared using a facile spin coating method and their properties can be further improved by surface modification of CdS and TiO2 layers.

Ultrastructure of Giant Mitochondria and Their Inclusions in Schwann Cells of Bovine Splenic Nerve

1974 ◽  
Vol 32 ◽  
pp. 194-195
Author(s):  
Å. Thureson-Klein
Keyword(s):  
Schwann Cells ◽  
Cell Organelles ◽  
Giant Mitochondria ◽  
Matrix Density ◽  
Physiological Conditions ◽  
Unmyelinated Axons ◽  
Internal Structures ◽  
Structural Abnormalities ◽  
Cytotoxic Compounds ◽  
Cell Components

Giant mitochondria of various shapes and with different internal structures and matrix density have been observed in a great number of tissues including nerves. In most instances, the presence of giant mitochondria has been associated with a known disease or with abnormal physiological conditions such as anoxia or exposure to cytotoxic compounds. In these cases degenerative changes occurred in other cell organelles and, therefore the giant mitochondria also were believed to be induced structural abnormalities.Schwann cells ensheating unmyelinated axons of bovine splenic nerve regularly contain giant mitochondria in addition to the conventional smaller type (Fig. 1). These nerves come from healthy inspected animals presumed not to have been exposed to noxious agents. As there are no drastic changes in the small mitochondria and because other cell components also appear reasonably well preserved, it is believed that the giant mitochondria are normally present jin vivo and have not formed as a post-mortem artifact.

Freeze-fracture observations on changes in the distribution of Filipin-sterol complexes during epididymal maturation and capacitation of boar spermatozoa

1990 ◽  
Vol 48 (3) ◽  
pp. 90-91
Author(s):  
N. Seki ◽  
Y. Toyama ◽  
T. Nagano
Keyword(s):  
Plasma Membrane ◽  
Essential Role ◽  
Freeze Fracture ◽  
Final Concentration ◽  
Freeze Fracturing ◽  
Physiological Conditions ◽  
Epididymal Maturation ◽  
Cacodylate Buffer ◽  
Sperm Membrane ◽  
Boar Spermatozoa

It is believed that i ntramembra.nous sterols play an essential role in membrane stability and permeability. To investigate the distribution changes of sterols in sperm membrane during epididymal maturation and capacitation, filipin has been used as a cytochemical probe for the detection for membrane sterols. Using this technique in combination with freeze fracturing, we examined the boar spermatozoa under various physiological conditions.The spermatozoa were collected from: 1) caput, corpus and cauda epididymides, 2) sperm rich fraction of ejaculates, and 3)the uterus 2hr after natural coition. They were fixed with 2.5% glutaraldehyde in 0.05M cacodylate buffer (pH 7.4), and treated with the filipin solution (final concentration : 0.02.0.05%) for 24hr at 4°C with constant agitation. After the filipin treatment, replicas were made by conventional freeze-fracture technique. The density of filipin-sterol complexes (FSCs) was determined in the E face of the plasma membrane of head regions.

Influence of stable iodine on the uptake of the thyroid – model vs. experiment

2001 ◽  
Vol 40 (01) ◽  
pp. 31-37 ◽  
Author(s):  
U. Wellner ◽  
E. Voth ◽  
H. Schicha ◽  
K. Weber
Keyword(s):  
Time Course ◽  
Compartment Model ◽  
The Body ◽  
Iodine Uptake ◽  
Model Calculations ◽  
Physiological Conditions ◽  
Iodine Supply ◽  
Predicted Values ◽  
The Individual ◽  
Stable Iodine

Summary Aim: The influence of physiological and pharmacological amounts of iodine on the uptake of radioiodine in the thyroid was examined in a 4-compartment model. This model allows equations to be derived describing the distribution of tracer iodine as a function of time. The aim of the study was to compare the predictions of the model with experimental data. Methods: Five euthyroid persons received stable iodine (200 μg, 10 mg). 1-123-uptake into the thyroid was measured with the Nal (Tl)-detector of a body counter under physiological conditions and after application of each dose of additional iodine. Actual measurements and predicted values were compared, taking into account the individual iodine supply as estimated from the thyroid uptake under physiological conditions and data from the literature. Results: Thyroid iodine uptake decreased from 80% under physiological conditions to 50% in individuals with very low iodine supply (15 μg/d) (n = 2). The uptake calculated from the model was 36%. Iodine uptake into the thyroid did not decrease in individuals with typical iodine supply, i.e. for Cologne 65-85 μg/d (n = 3). After application of 10 mg of stable iodine, uptake into the thyroid decreased in all individuals to about 5%, in accordance with the model calculations. Conclusion: Comparison of theoretical predictions with the measured values demonstrated that the model tested is well suited for describing the time course of iodine distribution and uptake within the body. It can now be used to study aspects of iodine metabolism relevant to the pharmacological administration of iodine which cannot be investigated experimentally in humans for ethical and technical reasons.

Interaction of Plasminogen Activators and Plasminogen with Heparin: Effect of Ionic Strength

1993 ◽  
Vol 70 (05) ◽  
pp. 867-872 ◽  
Author(s):  
Dingeman C Rijken ◽  
Gerard A W de Munk ◽  
Annie F H Jie
Keyword(s):  
Molecular Weight ◽  
Ionic Strength ◽  
Plasminogen Activator ◽  
Plasminogen Activators ◽  
Fibrinolytic System ◽  
Tissue Type ◽  
Single Chain ◽  
Physiological Conditions ◽  
Amino Terminal ◽  
Type Plasminogen Activator

SummaryIn order to define the possible effects of heparin on the fibrinolytic system under physiological conditions, we studied the interactions of this drug with plasminogen and its activators at various ionic strengths. As reported in recent literature, heparin stimulated the activation of Lys-plasminogen by high molecular weight (HMW) and low molecular weight (LMW) two-chain urokinase-type plasminogen activator (u-PA) and two-chain tissue-type plasminogen activator (t-PA) 10- to 17-fold. Our results showed, however, that this stimulation only occurred at low ionic strength and was negligible at a physiological salt concentration. Direct binding studies were performed using heparin-agarose column chromatography. The interaction between heparin and Lys-plasminogen appeared to be salt sensitive, which explains at least in part why heparin did not stimulate plasminogen activation at 0.15 M NaCl. The binding of u-PA and t-PA to heparinagarose was less salt sensitive. Results were consistent with heparin binding sites on both LMW u-PA and the amino-terminal part of HMW u-PA. Single-chain t-PA bound more avidly than two-chain t-PA. The interactions between heparin and plasminogen activators can occur under physiological conditions and may modulate the fibrinolytic system.

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