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Scientific Reports Jul 2019Variability in efficacy and safety is a worldwide concern with commercial probiotics for their growing and inevitable use in food and health sectors. Here, we introduce...
Variability in efficacy and safety is a worldwide concern with commercial probiotics for their growing and inevitable use in food and health sectors. Here, we introduce a probiotic thermophysical fingerprinting methodology using a coupling thermogravimetry and differential scanning calorimetry. Qualitative and quantitative information on the material decomposition and transition phases is provided under heating conditions. By monitoring the changes in both mass and internal energy over temperature and time, a couple of thermal data at the maximum decomposition steps allow the creation of a unique and global product identity, depending on both strain and excipient components. We demonstrate that each powder formulation of monostrain and multistrain from different lots and origins have a unique thermophysical profile. Our approach also provides information on the formulation thermostability and additive/excipient composition. An original fingerprint form is proposed by converting the generated thermal data sequence into a star-like pattern for a perspective library construction.
Topics: Biometric Identification; Calorimetry, Differential Scanning; DNA Fingerprinting; Excipients; Phenotype; Powders; Probiotics; Thermodynamics; Thermogravimetry
PubMed: 31292519
DOI: 10.1038/s41598-019-46469-1 -
AAPS PharmSciTech Dec 2007Polymeric film coatings have been applied to solid substrates for decorative, protective, and functional purposes. Irrespective of the reasons for coating, certain... (Review)
Review
Polymeric film coatings have been applied to solid substrates for decorative, protective, and functional purposes. Irrespective of the reasons for coating, certain properties of the polymer films may be determined as a method to evaluate coating formulations, substrate variables, and processing conditions. This article describes experimental techniques to assess various properties of both free and applied films, including water vapor and oxygen permeability, as well as thermal, mechanical, and adhesive characteristics. Methods to investigate interfacial interactions are also presented.
Topics: Adhesiveness; Chemistry, Pharmaceutical; Compressive Strength; Drug Compounding; Materials Testing; Models, Chemical; Oxygen; Permeability; Pharmaceutical Preparations; Polymers; Solubility; Surface Properties; Technology, Pharmaceutical; Tensile Strength; Thermogravimetry; Transition Temperature; Volatilization; Water
PubMed: 18181533
DOI: 10.1208/pt0804112 -
Scientific Reports Dec 2022In order to make full use of crop waste stalk, corn-stalk cellulose (CSC) was extracted by acid-base method and used as modifier of epoxy resin (E51) to prepare the...
In order to make full use of crop waste stalk, corn-stalk cellulose (CSC) was extracted by acid-base method and used as modifier of epoxy resin (E51) to prepare the self-extracted corn-stalk cellulose/epoxy resin composites (CSCEC). Differential scanning calorimeter (DSC), thermogravimetry (TG) analysis, dynamic mechanical analysis (DMA), morphology analysis by scanning electron microscope (SEM), the mechanical properties by electronic universal testing machine and impact testing machine were used for characterization and analysis. The experimental results showed that when the CSC content was 20 wt%, the impact strength of the composite was 2.50 kJ/m, which was 127.2% higher than that of pure epoxy resin. When the CSC content was 20 wt%, the Tg of epoxy resin obtained by DMA was the lowest, 167.4 °C, which decreased by 11.3 °C compared with that of pure epoxy resin. The SEM result showed that the fracture surface of the composite became obviously rough and had of obvious folds, which was a ductile fracture. These results indicated that the addition of CSC could toughen the epoxy resin.
Topics: Epoxy Resins; Cellulose; Zea mays; Tensile Strength; Thermogravimetry
PubMed: 36471157
DOI: 10.1038/s41598-022-25695-0 -
Molecular Pharmaceutics Jan 2022In this paper, several experimental techniques [X-ray diffraction, differential scanning calorimetry (DSC), thermogravimetry, Fourier transform infrared spectroscopy,...
In this paper, several experimental techniques [X-ray diffraction, differential scanning calorimetry (DSC), thermogravimetry, Fourier transform infrared spectroscopy, and broad-band dielectric spectroscopy] have been applied to characterize the structural and thermal properties, H-bonding pattern, and molecular dynamics of amorphous bosentan (BOS) obtained by vitrification and cryomilling of the monohydrate crystalline form of this drug. Samples prepared by these two methods were found to be similar with regard to their internal structure, H-bonding scheme, and structural (α) dynamics in the supercooled liquid state. However, based on the analysis of α-relaxation times (dielectric measurements) predicted for temperatures below the glass-transition temperature (), as well as DSC thermograms, it was concluded that the cryoground sample is more aged (and probably more physically stable) compared to the vitrified one. Interestingly, such differences in physical properties turned out to be reflected in the lower intrinsic dissolution rate of BOS obtained by cryomilling (in the first 15 min of dissolution test) in comparison to the vitrified drug. Furthermore, we showed that cryogrinding of the crystalline BOS monohydrate leads to the formation of a nearly anhydrous amorphous sample. This finding, different from that reported by Megarry et al. [ 2011, 346, 1061-1064] for trehalose (TRE), was revealed on the basis of infrared and thermal measurements. Finally, two various hypotheses explaining water removal upon cryomilling have been discussed in the manuscript.
Topics: Bosentan; Calorimetry, Differential Scanning; Dielectric Spectroscopy; Drug Liberation; Spectroscopy, Fourier Transform Infrared; Thermogravimetry; Vitrification; X-Ray Diffraction
PubMed: 34851124
DOI: 10.1021/acs.molpharmaceut.1c00613 -
Environmental Research Oct 2022The global consumption of plastic is growing year by year, producing small plastic pieces known as microplastics (MPs) that adversely affect ecosystems. The use of...
The global consumption of plastic is growing year by year, producing small plastic pieces known as microplastics (MPs) that adversely affect ecosystems. The use of organic amendments (compost and manure) polluted with MPs affects the quality of agricultural soils, and these MPs can be incorporated into the food chain and negatively impact human health. Current European legislation only considers large plastic particles in organic amendments. There is no information regarding MP pollution. Thus, the development of a methodology to support future legislation ensuring the quality of agricultural soils and food safety is necessary. This proposed methodology is based on thermogravimetry coupled with mass spectrometry to quantify polyethylene and polystyrene (PE and PS) MPs through their mass spectrometry signal intensity of characteristic PE (m/z 41, 43 and 56) and PS (m/z 78 and 104) ions. This method has been validated with several organic amendments where the MP content ranged from 52.6 to 4365.7 mg kg for PE-MPs and from 1.1 to 64.3 mg kg for PS-MPs. The proposed methodology is a quick and robust analytical method to quantify MPs in organic amendments that could support new legislation.
Topics: Ecosystem; Humans; Mass Spectrometry; Microplastics; Plastics; Polyethylene; Polystyrenes; Soil; Thermogravimetry; Water Pollutants, Chemical
PubMed: 35691386
DOI: 10.1016/j.envres.2022.113583 -
PloS One 2018To determine the effect of applied power settings, coil wetness conditions, and e-liquid compositions on the coil heating temperature for e-cigarettes with a "top-coil"...
OBJECTIVES
To determine the effect of applied power settings, coil wetness conditions, and e-liquid compositions on the coil heating temperature for e-cigarettes with a "top-coil" clearomizer, and to make associations of coil conditions with emission of toxic carbonyl compounds by combining results herein with the literature.
METHODS
The coil temperature of a second generation e-cigarette was measured at various applied power levels, coil conditions, and e-liquid compositions, including (1) measurements by thermocouple at three e-liquid fill levels (dry, wet-through-wick, and full-wet), three coil resistances (low, standard, and high), and four voltage settings (3-6 V) for multiple coils using propylene glycol (PG) as a test liquid; (2) measurements by thermocouple at additional degrees of coil wetness for a high resistance coil using PG; and (3) measurements by both thermocouple and infrared (IR) camera for high resistance coils using PG alone and a 1:1 (wt/wt) mixture of PG and glycerol (PG/GL).
RESULTS
For single point thermocouple measurements with PG, coil temperatures ranged from 322 ‒ 1008°C, 145 ‒ 334°C, and 110 ‒ 185°C under dry, wet-through-wick, and full-wet conditions, respectively, for the total of 13 replaceable coil heads. For conditions measured with both a thermocouple and an IR camera, all thermocouple measurements were between the minimum and maximum across-coil IR camera measurements and equal to 74% ‒ 115% of the across-coil mean, depending on test conditions. The IR camera showed details of the non-uniform temperature distribution across heating coils. The large temperature variations under wet-through-wick conditions may explain the large variations in formaldehyde formation rate reported in the literature for such "top-coil" clearomizers.
CONCLUSIONS
This study established a simple and straight-forward protocol to systematically measure e-cigarette coil heating temperature under dry, wet-through-wick, and full-wet conditions. In addition to applied power, the composition of e-liquid, and the devices' ability to efficiently deliver e-liquid to the heating coil are important product design factors effecting coil operating temperature. Precautionary temperature checks on e-cigarettes under manufacturer-recommended normal use conditions may help to reduce the health risks from exposure to toxic carbonyl emissions associated with coil overheating.
Topics: Electronic Nicotine Delivery Systems; Heating; Humans; Temperature; Thermogravimetry; Thermometers
PubMed: 29672571
DOI: 10.1371/journal.pone.0195925 -
Waste Management & Research : the... Sep 2020Thermogravimetric analysis (TGA) is the most widespread thermal analytical technique applied to waste materials. By way of critical review, we establish a theoretical... (Review)
Review
Thermogravimetric analysis (TGA) is the most widespread thermal analytical technique applied to waste materials. By way of critical review, we establish a theoretical framework for the use of TGA under conditions for compositional analysis of waste-derived fuels from municipal solid waste (MSW) (solid recovered fuel (SRF), or refuse-derived fuel (RDF)). Thermal behaviour of SRF/RDF is described as a complex mixture of several components at multiple levels (including an assembly of prevalent waste items, materials, and chemical compounds); and, operating conditions applied to TGA experiments of SRF/RDF are summarised. SRF/RDF mainly contains cellulose, hemicellulose, lignin, polyethylene, polypropylene, and polyethylene terephthalate. Polyvinyl chloride is also used in simulated samples, for its high chlorine content. We discuss the main limitations for TGA-based compositional analysis of SRF/RDF, due to inherently heterogeneous composition of MSW at multiple levels, overlapping degradation areas, and potential interaction effects among waste components and cross-contamination. Optimal generic TGA settings are highlighted (inert atmosphere and low heating rate (⩽10°C), sufficient temperature range for material degradation (⩾750°C), and representative amount of test portion). There is high potential to develop TGA-based composition identification and wider quality assurance and control methods using advanced thermo-analytical techniques (e.g. TGA with evolved gas analysis), coupled with statistical data analytics.
Topics: Garbage; Incineration; Refuse Disposal; Solid Waste; Thermogravimetry
PubMed: 32705957
DOI: 10.1177/0734242X20941085 -
Molecules (Basel, Switzerland) Jul 2020Biobased monomers have been used to replace their petroleum counterparts in the synthesis of polymers that are aimed at different applications. However, environmentally...
Biobased monomers have been used to replace their petroleum counterparts in the synthesis of polymers that are aimed at different applications. However, environmentally friendly polymerization processes are also essential to guarantee greener materials. Thus, photoinduced polymerization, which is low-energy consuming and solvent-free, rises as a suitable option. In this work, eugenol-, isoeugenol-, and dihydroeugenol-derived methacrylates are employed in radical photopolymerization to produce biobased polymers. The polymerization is monitored in the absence and presence of a photoinitiator and under air or protected from air, using Real-Time Fourier Transform Infrared Spectroscopy. The polymerization rate of the methacrylate double bonds was affected by the presence and reactivity of the allyl and propenyl groups in the eugenol- and isoeugenol-derived methacrylates, respectively. These groups are involved in radical addition, degradative chain transfer, and termination reactions, yielding crosslinked polymers. The materials, in the form of films, are characterized by differential scanning calorimetry, thermogravimetric, and contact angle analyses.
Topics: Eugenol; Light; Methacrylates; Molecular Structure; Polymerization; Spectrum Analysis; Thermogravimetry
PubMed: 32751133
DOI: 10.3390/molecules25153444 -
Journal of Oleo Science 2015According to the conventional Gibbs adsorption model, which is a common assumption about the molecular concentration at surfaces, the adsorbed film of soluble... (Review)
Review
According to the conventional Gibbs adsorption model, which is a common assumption about the molecular concentration at surfaces, the adsorbed film of soluble amphiphiles is located at the air/solution interface just like Langmuir monolayer which is illustrated in many physical chemistry text books on "Colloid and Interface Science". According to many proofs of the experimental results here, the newer idea for the surface adsorption is confirmed and explained, which is quite different from the conventional Gibbs surface excess model at the air/solution interface.
Topics: Adsorption; Air; Ethylene Glycol; Models, Theoretical; Pyrenes; Solubility; Solutions; Spectrometry, Fluorescence; Surface Properties; Surface-Active Agents; Thermogravimetry; Unilamellar Liposomes; Volatilization; Water
PubMed: 25742921
DOI: 10.5650/jos.ess14213 -
Molecules (Basel, Switzerland) Jun 2018Noble metal aerogels offer a wide range of catalytic applications due to their high surface area and tunable porosity. Control over monolith shape, pore size, and...
Noble metal aerogels offer a wide range of catalytic applications due to their high surface area and tunable porosity. Control over monolith shape, pore size, and nanofiber diameter is desired in order to optimize electronic conductivity and mechanical integrity for device applications. However, common aerogel synthesis techniques such as solvent mediated aggregation, linker molecules, sol⁻gel, hydrothermal, and carbothermal reduction are limited when using noble metal salts. Here, we present the synthesis of palladium aerogels using carboxymethyl cellulose nanofiber (CNF) biotemplates that provide control over aerogel shape, pore size, and conductivity. Biotemplate hydrogels were formed via covalent cross linking using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) with a diamine linker between carboxymethylated cellulose nanofibers. Biotemplate CNF hydrogels were equilibrated in precursor palladium salt solutions, reduced with sodium borohydride, and rinsed with water followed by ethanol dehydration, and supercritical drying to produce freestanding aerogels. Scanning electron microscopy indicated three-dimensional nanowire structures, and X-ray diffractometry confirmed palladium and palladium hydride phases. Gas adsorption, impedance spectroscopy, and cyclic voltammetry were correlated to determine aerogel surface area. These self-supporting CNF-palladium aerogels demonstrate a simple synthesis scheme to control porosity, electrical conductivity, and mechanical robustness for catalytic, sensing, and energy applications.
Topics: Carboxymethylcellulose Sodium; Dielectric Spectroscopy; Gels; Microscopy, Electron, Scanning; Nanofibers; Palladium; Thermogravimetry; X-Ray Diffraction
PubMed: 29890763
DOI: 10.3390/molecules23061405