scholarly journals Monolayers of Cholesterol and Cholesteryl Stearate at the Water/Vapor Interface: A Physico-Chemical Study of Components of the Meibum Layer

2021 ◽  
Vol 5 (2) ◽  
pp. 30
Author(s):  
Ramón G. Rubio ◽  
Eduardo Guzmán ◽  
Francisco Ortega ◽  
Libero Liggieri
Keyword(s):  
Cell Membranes ◽  
Mechanical Performance ◽  
Chemical Properties ◽  
Langmuir Monolayers ◽  
Tear Film ◽  
Chemical Study ◽  
Lipid Monolayer ◽  
Molar Ratio ◽  
Physico Chemical

Langmuir monolayers containing different amounts of cholesterol and cholesteryl stearate were studied at two different temperatures (24 °C and 35 °C). The main goal was to contribute towards the understanding of how the variations in the chemical composition may affect the physico-chemical properties of these specific lipid monolayers. The model mixture was chosen considering that cholesteryl esters are present in cell membranes and some other biological systems, including human tear lipids. Therefore, an investigation into the effect of the lipid monolayer composition on their interfacial properties may elucidate some of the fundamental reasons for the deficiencies in cell membranes and tear film functioning in vivo. The experimental results have shown that the molar ratio of the mixture plays a crucial role in the modulation of the Langmuir film properties. The condensing effects of the cholesterol and the interactions between the lipids in the monolayer were the main factors altering the monolayer response to dilatational deformation. The modification of the mixture compositions leads to significant changes in the Langmuir films and the mechanical performance, altering the ability of the monolayer to reduce the surface tension and the viscoelastic properties of the monolayers. This suggests that subtle modifications of the biomembrane composition may significantly alter its physiological function.

scholarly journals Interaction of Particles with Langmuir Monolayers of 1,2-Dipalmitoyl-Sn-Glycero-3-Phosphocholine: A Matter of Chemistry?

Coatings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 469 ◽  
Author(s):  
Eduardo Guzmán ◽  
Eva Santini ◽  
Michele Ferrari ◽  
Libero Liggieri ◽  
Francesca Ravera
Keyword(s):  
Mechanical Performance ◽  
Lung Surfactant ◽  
Langmuir Monolayers ◽  
Tear Film ◽  
Potential Health ◽  
Specific Chemical ◽  
Physico Chemical ◽  
Pressure Area ◽  
The Impact ◽  
Lipid Layers

Lipid layers are considered among the first protective barriers of the human body against pollutants, e.g., skin, lung surfactant, or tear film. This makes it necessary to explore the physico-chemical bases underlying the interaction of pollutants and lipid layers. This work evaluates using a pool of surface-sensitive techniques, the impact of carbon black and fumed silica particles on the behavior of Langmuir monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). The results show that the incorporation of particles into the lipid monolayers affects the surface pressure–area isotherm of the DPPC, modifying both the phase behavior and the collapse conditions. This is explained considering that particles occupy a part of the area available for lipid organization, which affects the lateral organization of the lipid molecules, and consequently the cohesion interactions within the monolayer. Furthermore, particles incorporation worsens the mechanical performance of lipid layers, which may impact negatively in different processes presenting biological relevance. The modification induced by the particles has been found to be dependent on their specific chemical nature. This work tries to shed light on some of the most fundamental physico-chemical bases governing the interaction of pollutants with lipid layers, which plays an essential role on the design of strategies for preventing the potential health hazards associated with pollution.

Mining a Nanoparticle Dataset, Compiled Within the MODENA-COST Action

2021 ◽  
pp. 1706-1724
Author(s):  
Sabine Van Miert ◽  
Jan Creylman ◽  
Geert R. Verheyen
Keyword(s):  
Chemical Properties ◽  
In Vitro Testing ◽  
Cost Action ◽  
Robust Model ◽  
Physico Chemical ◽  
Classification And Regression ◽  
Toxic Potential ◽  
Sheer Number

Engineered nanomaterials (ENM) have new or enhanced physico-chemical properties compared to their micron-sized counterparts, but may also have an increased toxic potential. Animal and in vitro testing are typically employed to investigate the toxic effects of (nano)materials. The sheer number of ENMs and their physico-chemical parameters make it impossible to only use in vivo and in vitro testing, and modelling technologies are also deployed to find relationships between ENM parameters and toxicity. A heterogenous dataset containing information on 192 nanoparticle endpoints was compiled within the MODENA COST-Action consortium. Here, the available data was mined to identify relationships between nanoparticle properties and cell-death as measured with four cytotoxicity assays. ANOVA, collinearity analyses and classification and regression trees gave indications on potential relations between the NP-properties and toxicity, but could not deliver a robust model. More information and datapoints are necessary to build well-validated models.

scholarly journals In Vitro Physico-Chemical Characterization and Standardized In Vivo Evaluation of Biocompatibility of a New Synthetic Membrane for Guided Bone Regeneration

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1186
Author(s):  
Lívia da Costa Pereira ◽  
Carlos Fernando de Almeida Barros Mourão ◽  
Adriana Terezinha Neves Novellino Alves ◽  
Rodrigo Figueiredo de Brito Resende ◽  
Marcelo José Pinheiro Guedes de Uzeda ◽  
...  
Keyword(s):  
Bone Regeneration ◽  
Chemical Properties ◽  
Chemical Characterization ◽  
Guided Bone Regeneration ◽  
Tissue Reaction ◽  
In Vivo Evaluation ◽  
Physico Chemical ◽  
Tissue Reactions

This study’s aim was to evaluate the biocompatibility and bioabsorption of a new membrane for guided bone regeneration (polylactic-co-glycolic acid associated with hydroxyapatite and β-tricalcium phosphate) with three thicknesses (200, 500, and 700 µm) implanted in mice subcutaneously. Scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and the quantification of carbon, hydrogen and nitrogen were used to characterize the physico-chemical properties. One hundred Balb-C mice were divided into 5 experimental groups: Group 1—Sham (without implantation); Group 2—200 μm; Group 3—500 μm; Group 4—700 μm; and Group 5—Pratix®. Each group was subdivided into four experimental periods (7, 30, 60 and 90 days). Samples were collected and processed for histological and histomorphometrical evaluation. The membranes showed no moderate or severe tissue reactions during the experimental periods studied. The 500-μm membrane showed no tissue reaction during any experimental period. The 200-μm membrane began to exhibit fragmentation after 30 days, while the 500-μm and 700-µm membranes began fragmentation at 90 days. All membranes studied were biocompatible and the 500 µm membrane showed the best results for absorption and tissue reaction, indicating its potential for clinical guided bone regeneration.

scholarly journals Optimization of Innovative Three-Dimensionally-Structured Hybrid Vesicles to Improve the Cutaneous Delivery of Clotrimazole for the Treatment of Topical Candidiasis

Pharmaceutics ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 263 ◽  
Author(s):  
Maria Letizia Manca ◽  
Iris Usach ◽  
José Esteban Peris ◽  
Antonella Ibba ◽  
Germano Orrù ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Properties ◽  
Chemical Characterization ◽  
Yeast Cells ◽  
Unilamellar Vesicles ◽  
Transmission Electron ◽  
Physico Chemical

New three-dimensionally-structured hybrid phospholipid vesicles, able to load clotrimazole in a high amount (10 mg/mL), were obtained for the first time in this work by significantly reducing the amount of water (≤10%), which was replaced with a mixture of glycerol and ethanol (≈90%). A pre-formulation study was carried out to evaluate the effect of both the composition of the hydrating medium and the concentration of the phospholipid on the physico-chemical properties of hybrid vesicles. Four different three-dimensionally-structured hybrid vesicles were selected as ideal systems for the topical application of clotrimazole. An extensive physico-chemical characterization performed using transmission electron microscopy (TEM), cryogenic transmission electron microscopy (cryo-TEM), 31P-NMR, and small-angle X-ray scattering (SAXS) displayed the formation of small, multi-, and unilamellar vesicles very close to each other, and was capable of forming a three-dimensional network, which stabilized the dispersion. Additionally, the dilution of the dispersion with water reduced the interactions between vesicles, leading to the formation of single unilamellar vesicles. The evaluation of the in vitro percutaneous delivery of clotrimazole showed an improved drug deposition in the skin strata provided by the three-dimensionally-structured vesicles with respect to the commercial cream (Canesten®) used as a reference. Hybrid vesicles were highly biocompatible and showed a significant antifungal activity in vitro, greater than the commercial cream Canesten®. The antimycotic efficacy of formulations was confirmed by the reduced proliferation of the yeast cells at the site of infection in vivo. In light of these results, clotrimazole-loaded, three-dimensionally-structured hybrid vesicles appear to be one of the most innovative and promising formulations for the treatment of candidiasis infections.

scholarly journals Eudragit S100 Entrapped Liposome for Curcumin Delivery: Anti-Oxidative Effect in Caco-2 Cells

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 114 ◽  
Author(s):  
Vincenzo De Leo ◽  
Sante Di Gioia ◽  
Francesco Milano ◽  
Paola Fini ◽  
Roberto Comparelli ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Polymeric Coating ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Physico Chemical ◽  
Eudragit S100 ◽  
Natural Polyphenol ◽  
Anti Oxidant ◽  
Small Unilamellar Vesicles

Curcumin is a natural polyphenol with strong antioxidant activity. However, this molecule shows a very poor bioavailability, instability, and rapid metabolism in vivo. In this work curcumin was loaded in Eudragit-coated liposomes to create a gastroresistant carrier, able to protect its load from degradation and free it at the site of absorption in the colon region. Small unilamellar vesicles were prepared and coated with Eudragit by a pH-driven method. The physico-chemical properties of the prepared systems were assessed by light scattering, transmission electron microscopy, infrared spectroscopy, and differential scanning calorimetry. The uptake of vesicles by Caco-2 cells and the anti-oxidant activity in cells were evaluated. The produced vesicles showed dimensions of about forty nanometers that after covering with Eudragit resulted to have micrometric dimensions at acid pH. The experiments showed that at pH > 7.0 the polymeric coating dissolves, releasing the nanometric liposomes and allowing them to enter Caco-2 cells. Delivered curcumin loaded vesicles were then able to decrease significantly ROS levels as induced by H2O2 in Caco-2 cells. The proposed work showed the possibility of realizing effective gastroresistant curcumin liposome formulations for the delivery of antioxidant molecules to Caco-2 cells, potentially applicable to the treatment of pathological conditions related to intestinal oxidative stress.

scholarly journals Influence of Dispersing Method on the Quality of Nano-Admixtures Homogenization in Cement Matrix

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4865
Author(s):  
Elżbieta Horszczaruk ◽  
Paweł Łukowski ◽  
Cyprian Seul
Keyword(s):  
High Speed ◽  
Mechanical Performance ◽  
Chemical Properties ◽  
Cement Composite ◽  
Cement Matrix ◽  
Cement Composites ◽  
Nano Sio2 ◽  
Mechanical Stirring ◽  
Physico Chemical ◽  
Nano Fe3o4

In recent years, a nano-modification of the cement composites allowed to develop a number of new materials. The use of even small amount of nano-admixture makes possible not only to improve the physico-mechanical properties of the cement materials, but also to obtain the composite with high usability, optimised for the given application. The basic problem of nano-modification of the cement composites remains the effectiveness of dispersing the nanomaterials inside the cement matrix. This paper deals with the effect of the type and size of the nanoparticles on the tendency to their agglomeration in the cement matrix. The main techniques and methods of dispersing the nanomaterials are presented. It has been demonstrated, on the basis of the results of testing of three nanomodifiers of 0D type (nano-SiO2, nano-Fe3O4 and nano-Pb3O4), how the structure and properties of the nanomaterial affect the behaviour of the particles when dissolving in the mixing water and applying a superplasticiser. The nanoparticles had similar size of about 100 nm but different physico-chemical properties. The methods of dispersing covered the use of high-speed mechanical stirring and ultrasonication. The influence of the method of nano-modifier dispersing on the mechanical performance of the cement composite has been presented on the basis of the results of testing the cement mortars modified with 3% admixture of nano-SiO2.

Potential Applications of Biphosphonates in Dental Surgical Implants

2007 ◽  
Vol 20 (3) ◽  
pp. 455-465 ◽  
Author(s):  
D. Berardi ◽  
T. Carlesi ◽  
F. Rossi ◽  
M. Calderini ◽  
R. Volpi ◽  
...  
Keyword(s):  
Alveolar Bone ◽  
Chemical Properties ◽  
Osteonecrosis Of The Jaw ◽  
In Vivo Experiments ◽  
Surgical Implants ◽  
Physico Chemical ◽  
Potential Applications ◽  
Collateral Effect

Biphosphonates are largely used for their unquestionable properties of inhibiting bone resorption by osteoclast in the treatment of various osteometabolic illnesses such as osteoporosis, multiple myeloma, tumors which metastasize to the bone and malignant hypercalcemia. In this literature review the physico-chemical properties, biologic activities and the mechanisms of action of biphosphonates are described. The use of these drugs is discussed, analyzing the quantity of results which have emerged through in vitro and in vivo experiments on animal models. In this study the efficiency of these drugs is demonstrated in contrasting the osteolitic processes of the alveolar bone, in promoting the neoformation and in bettering the quality of bone implants. However, it is important to draw attention to a worrying correlation which has emerged during the last 3–4 years, between osteonecrosis of the jaw (ONJ) and the systemic administration of aminobiphosphonates. This collateral effect did not emerge following the use of non-aminobiphosphonates. The aim of this revie w is to identify the guidelines for the use of biphosphonates in oral implant surgery.

SYNTHESIS OF SPATIALLY-HINDERED METHYLCYCLOALKYLPHENOLS AND SOME PECULIARITIES OF THEIR AMINOMETHYLATION REACTIONS BY AMINOETHYLNONYLIMIDAZOLINE

1970 ◽  
Author(s):  
Zaur Z. Aghamaliyev ◽  
Vagif M. Abbasov ◽  
Chingiz K. Rasulov ◽  
Igrar G. Nazarov ◽  
Nigar S. Rzaeva ◽  
...  
Keyword(s):  
Maximum Yield ◽  
Chemical Properties ◽  
Mannich Bases ◽  
Point Of View ◽  
Molar Ratio ◽  
Theoretical Point ◽  
Target Product ◽  
Substituted Phenols ◽  
Catalyst Amount ◽  
Physico Chemical

The paper deals with the results of cycloalkylation of phenol with 1-methylcyclopentene, 1(3)-methylcyclohexene in the presence of aluminum phenolate catalyst and influence of various parameters on the yield of the target product. The reaction temperature was varied from 220 to 280 °C, the reaction time - from 1 to 7 h, molar ratio of phenol to cyclene – from 1:1 to 1:3 mol/mol, the catalyst amount – from 10 to 25%. Maximum yield of 2,6-di(1(3)-methylcycloalkyl)phenols is obtained under the following conditions: temperature - 260-280 °C, duration - 5-6 h, molar ratio of phenol to 1(3)-methylcycloalkene - 1:2 mol/mol and the catalyst amount is 20% based on taken phenol. Simultaneously, the yield of the target products - 2,6-di-(1(3)-methylcycloalkyl)phenols is 44.3-47.1% per taken phenol, the selectivity is 67.4 71.2% on the target product. As a result of the chromatographic studies of the products of phenol cycloalkylation with 1(3)-methylcycloalkenes in the presence of aluminum phenolate catalyst it became clear that the alkylate mainly contains 2,6-dicycloalkyl-substituted phenols (87.4-92.3%). After rectification of the alkylate at low pressure (20 mm Hg), the target products were obtained with a purity of 96.7-98.1% and their physico-chemical properties were determined. The resulting 2,6-di-(1(3)-methylcycloalkyl)phenols were aminomethylated by formaldehyde and aminoethylnonylimidazoline at the ratio of 1:2:2.From theoretical point of view, Mannich bases were obtained with yield of 65.7-71.7% by the interaction of 2,6-di-[1(3)-methylcycloalkyl]phenols with formaldehyde and aminoethylnonyl imidazoline. Physico-chemical properties of synthesized 4-hydroxy-3,5-di-(1(3)-methylcycloalkyl)benzylaminoethylnonylimidazolines were determined.

scholarly journals Chemical Properties of Groundwater in Bhiloda Taluka Region, North Gujarat, India

2008 ◽  
Vol 5 (4) ◽  
pp. 792-796 ◽  
Author(s):  
G. D. Acharya ◽  
M. V. Hathi ◽  
Asha D. Patel ◽  
K. C. Parmar
Keyword(s):  
Chemical Properties ◽  
Water Source ◽  
Chemical Study ◽  
Quality Parameters ◽  
Sodium Adsorption Ratio ◽  
Sodium Potassium ◽  
Physico Chemical ◽  
Groundwater Samples ◽  
Sabarkantha District ◽  
North Gujarat

Groundwater is one of the most useful water sources. Contamination of such water source is a big problem creating health hazards. In this present study we have collected groundwater samples from different places of Bhiloda taluka of Sabarkantha district (North Gujarat) India. These samples have been assessed on the basis of various qualitative parameters. The results of physico-chemical study of water samples from 13 bore wells in Bhiloda taluka are presented. The water quality parameters such as; pH, electrical conductivity (EC), total dissolved salts (TDS), calcium and magnesium, sodium, potassium, carbonate, bicarbonate, chloride, sulphate, fluoride, sodium adsorption ratio (SAR), residual sodium carbonate (RSC) and soluble sodium percentage ( SSP ) were estimated.

scholarly journals Changes in the Physico-Chemical Properties of Human Kidney Cell Membranes during the Cancer Transformation

2014 ◽  
Vol 04 (04) ◽  
pp. 223-231 ◽  
Author(s):  
Barbara Szachowicz-Petelska ◽  
Izabela Dobrzyńska ◽  
Zbigniew A. Figaszewski ◽  
Jacek Kudelski
Keyword(s):  
Kidney Cell ◽  
Cell Membranes ◽  
Chemical Properties ◽  
Human Kidney ◽  
Physico Chemical
Sign in / Sign up

Export Citation Format

Share Document