Publications by authors named "Ropers M"

Introduction: During the coronavirus disease 2019 (COVID-19) pandemic, the Gustave Roussy Cancer Center introduced teleconsultation via telephone, as an alternative to face-to-face consultation to reduce patient hospital visits. This study was designed to assess patient and doctor satisfaction with this modality of care in oncology patient care during the period of the pandemic and beyond.

Methods: We designed two questionnaires based on validated scores to assess satisfaction from teleconsultation in patients (EORTC OUT-PATSAT 35 and Telemedicine Satisfaction Questionnaire [TSQ] scores) and doctors (Telehealth Usability Questionnaire [TUQ]), and anxiety levels in both groups (anxiety section of the Hospital Anxiety and Depression Scale [HADS], HADS-A).

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The growing consumption of fermented products has led to an increasing demand for lactic acid bacteria (LAB), especially for LAB tolerant to freezing/thawing conditions. Carnobacterium maltaromaticum is a psychrotrophic and freeze-thawing resistant lactic acid bacterium. The membrane is the primary site of damage during the cryo-preservation process and requires modulation to improve cryoresistance.

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Tricalcium phosphate (TCP) is a food additive, labeled E341(iii), used in powdered food preparation, such as baby formula. In the United States, calcium phosphate nano-objects were identified in baby formula extractions. Our goal is to determine whether the TCP food additive, as is used in Europe, can be classified as a nanomaterial.

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Aim: This study investigates the individual and combined effects of fermentation parameters for improving cell biomass productivity and the resistance to freezing, freeze-drying, and freeze-dried storage of Lactobacillus delbrueckii subsp. bulgaricus CFL1.

Methods And Results: Cells were cultivated at different temperatures (42°C and 37°C) and pH values (5.

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(1) Background: The anthocyanin delphinidin exhibits anti-angiogenic properties both in in vitro and in vivo angiogenesis models. However, in vivo delphinidin is poorly absorbed, thus its modest bioavailability and stability reduce its anti-angiogenic effects. The present work takes advantage of small extracellular vesicle (sEV) properties to enhance both the stability and efficacy of delphinidin.

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Titanium dioxide is a food additive that has raised some concerns for humans due to the presence of nanoparticles. We were interested in knowing the fate of TiO2 particles in the gastro-intestinal tract and their potential effect on digestive enzymes. For this purpose, we analysed the behaviour of two different food grade TiO2 samples (E171) and one nano-sized TiO2 sample (P25) through a standardized static in vitro digestion protocol simulating the oral, gastric and intestinal phases with appropriate juices including enzymes.

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Colloidal silver products are sold for a wide range of disinfectant and health applications. This has increased the potential for human exposure to silver nanoparticles (AgNPs) and ions (Ag), for which oral ingestion is considered to be a major route of exposure. Our objective was to evaluate and compare the toxicity of two commercially available colloidal silver products on two human intestinal epithelial models under realistic exposure conditions.

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Hundreds of consumer and commercial products containing silver nanoparticles (AgNPs) are currently used in food, personal-care products, pharmaceutical, and many other applications. Human exposure to AgNPs includes oral intake, inhalation, and dermal contact. The aim of this review was to focus on oral intake, intentional and incidental of AgNPs where well-known antimicrobial characteristics that might affect the microbiome and mucus in the gastrointestinal tract (GIT).

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Titanium dioxide is a metal oxide used as a white pigment in many food categories, including confectionery. Due to differences in the mass fraction of nanoparticles contained in TiO, the estimated intakes of TiO nanoparticles differ by a factor of 10 in the literature. To resolve this problem, a better estimation of the mass of nanoparticles present in food products is needed.

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Titanium dioxide (TiO) nanoparticles (NPs) are used as an additive (E171 or INS171) in foods such as gum, candy and puddings. To address concerns about the potential hazardous effects of ingested NPs, the toxicity of these food-grade NPs was investigated with a defined model intestinal bacterial community. Each titania preparation (food-grade TiO formulations, E171-1 and E171-6a) was tested at concentrations equivalent to those found in the human intestine after sampling 1-2 pieces of gum or candy (100-250 ppm).

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The miscibility of milk sphingomyelin (milk-SM) and cholesterol was investigated in this study. The effect of different physical states of milk-SM on its interactions with cholesterol was determined by the recording of isotherms of compression of Langmuir films for temperatures above and below the gel to Lα phase transition of milk-SM (T∼34°C). For T=15°C View Article and Find Full Text PDF

Titanium dioxide (TiO) is a transition metal oxide widely used as a white pigment in various applications, including food. Due to the classification of TiO nanoparticles by the International Agency for Research on Cancer as potentially harmful for humans by inhalation, the presence of nanoparticles in food products needed to be confirmed by a set of independent studies. Seven samples of food-grade TiO (E171) were extensively characterised for their size distribution, crystallinity and surface properties by the currently recommended methods.

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This study comprises 3 experiments exploring the possible benefits and mechanism of action of liposomes for chilling (4°C) canine sperm over a period of 4 days. In the first experiment, 20 ejaculates collected from 5 Beagle dogs were chilled in an extender containing 6% low density lipoproteins (LDL) (Control), or one of 7 extenders containing different concentrations (2, 4, 6, 8, 10, 15, 20%) of liposomes (LIPO). These ejaculates were chilled over 4 days and motility was assessed daily using a Hamilton Thorne analyzer (HTM-IVOS, 14.

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Binder of SPerm (BSP) proteins, the main proteins from bovine seminal plasma, are known to partially intercalate into the outer leaflet of the spermatozoa membrane and bind to choline-containing lipids being present therein. This insertion generates a negative effect on semen quality after cryopreservation by inducing an early-stage capacitation of spermatozoa. The assumption of surface properties exhibited by BSP proteins was checked by tensiometry measurements: BSP proteins are highly surface active.

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A systematic study was carried out on monolayer films and lipid vesicles to elucidate the interactions between membrane lipids and commercial particles of titanium dioxide TiO2 (TiO2-P25). Pressure-area isotherms of lipids at various pH values were recorded on a Langmuir trough with or without TiO2-P25 and NaCl in the subphase. Electrophoretic mobilities of lipid vesicles and TiO2-P25 particles were measured to identify the pH range where attractive electrostatic interactions between lipids and TiO2-P25 could take place.

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Cryopreservation is widely used to preserve the quality of bull spermatozoa over time. Sequestration of seminal plasma proteins by low density lipoproteins and formation of a protective film around the spermatozoa membrane by low density lipoproteins were the main mechanisms proposed. However, the organization of lipids in the outer leaflet of the spermatozoa membrane has been never considered as a possible parameter.

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Lipid oxidation is a major cause for the degradation of biological systems and foods, but the intricate relationship between lipid oxidation and protein modifications in these complex multiphase systems remains unclear. The objective of this work was to have a spatial and temporal insight of the modifications undergone by the interfacial or the unadsorbed proteins in oil-in-water emulsions during lipid oxidation. Tryptophan fluorescence and oxygen uptake were monitored simultaneously during incubation in different conditions of protein-stabilized oil-in-water emulsions.

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The development of lipid oxidation in oil-in-water (O/W) emulsions is widely influenced by the properties of the interfacial layer, which separates the oil and water phases. In this work, the effect of the structure of the interface on the oxidative stability of surfactant stabilized O/W emulsions was investigated. Emulsions were prepared with either single Tween 20 or Tween 20/co-surfactant mixtures in limiting amounts.

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Article Synopsis
  • The stability of oil-in-water (O/W) emulsions during oxidation is influenced by the type of emulsifier used.
  • In a study, emulsions with similar droplet sizes were tested for oxidation at 25 °C with an iron-EDTA complex, while varying the pH and emulsifier amounts to assess their effects.
  • Results showed that interfaces stabilized by proteins are less effective at preventing lipid oxidation compared to those stabilized by surfactants, and it was also found that unadsorbed proteins can provide antioxidant benefits.
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Unadsorbed emulsifiers affect the physical and chemical behaviour of oil-in-water (O/W) emulsions. A simple methodology to quantify unadsorbed emulsifiers in the aqueous phase of O/W emulsions has been developed. Emulsions were centrifuged and filtered to separate the aqueous phase from the oil droplets and the concentration of unadsorbed emulsifiers in the aqueous phase determined.

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Beta-casein (beta-CN) is a milk protein widely used in food industries because of its mild emulsifying properties due to its amphiphilicity. However, the elements determining its micellization behavior in solution and interfacial behavior at the air-water interface are not well known. In order to study how the forced dimerisation influences functional properties of beta-CN, recombinant wild-type beta-CN was produced and distal cysteinylated forms of recombinant beta-CN were engineered.

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A non-radioactive blot binding assay has proved the capacity of a purified recombinant form of Arabidopsis thaliana caleosin (AtClo1), a key protein of this plant oil body, to bind calcium. Calcium affected recombinant caleosin aggregation state, solubility, and electrophoretic mobility on SDS-PAGE. The effect of calcium on interfacial behavior of recombinant caleosin was studied at three interfaces: air/water (A/W), purified oil/water (O/W), and air/phosholipid/water (A/PLs/W).

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The binding of a cationic surfactant (hexadecyltrimethylammonium bromide, CTAB) to a negatively charged natural polysaccharide (pectin) at air-solution interfaces was investigated on single interfaces and in foams, versus the linear charge densities of the polysaccharide. Besides classical methods to investigate polymer/surfactant systems, we applied, for the first time concerning these systems, the analogy between the small angle neutron scattering by foams and the neutron reflectivity of films to measure in situ film thicknesses of foams. CTAB/pectin foam films are much thicker than the pure surfactant foam film but similar for high- and low-charged pectin/CTAB systems despite the difference in structure of complexes at interfaces.

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Pectins are anionic polysaccharides that are sensitive to cations, a property that is widely used in food science. The interactions of a cationic lipid film (dimethyldioctadecylammonium bromide, DODAB) with a set of pectins bearing the same charge, which was either distributed randomly or pseudorandomly or blockwise, are investigated. The combination of Brewster angle microscopy BAM and infrared reflection-absorption spectroscopy IRRAS at the air-water interface reveals that pectin strongly binds to the cationic lipid film in forming a stacked layer underneath the lipid film.

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