Laplace inversions applied to multi–component T2–T2 exchange experiments

Two-dimensional (2D) T2-T2 molecular exchange NMR experiments with a period of magnetization storage between the two T2 relaxation encoding periods are presented. The two-dimensional time map was inverted using a fast Laplace algorithm to obtain the T2–T2 exchange map. T2–MZ(store)–T2 2D 1H NMR spectra recorded at high and low homogeneous magnetic fields of water and oil in sand, air bubbles in water and foams, exchange of liquid / foam and liquid / saturated vapours of chloroform are presented. Uni– and bi–directional exchange was observed for bubbles in water, superficial liquid shell, and foam

Coacervation of Elastin-Like Recombinamer Microgels

Producción CientíficaThe investigation of the coacervation (self-aggregation) behavior of biomicrogels which can potentially be used as drug carriers is an important topic, because self-aggregation can not only cause loss of activity, but also toxicity and immunogenicity. To study this effect microgels from elastin-like recombinamer are synthesized using miniemulsion technique. The existence of coacervation for such microgels, at different concentrations and temperatures, is studied and proved by cryo-field emission scanning clectron microscopy (cryo-FESEM), cryo-transmission electron microscopy (cryo-TEM), and by a novel 1H high-resolution magic angle sample spinning (HRMAS), nuclear magnetic resonance (NMR) spectroscopy, and relaxometry methods. The findings by 1H HRMAS NMR spectroscopy and relaxometry show simultaneous processes of volume phase temperature transition and coacervation with different sensitivity for hydrophobic and hydrophilic amino acid side-chains in the microgel. The coacervation process is more evidential by the behavior of glycine α-CH2, 1H NMR peak as compared to the proline β-CH2.2019-12-122019-12-12Ministerio de Industria, Economía y Competitividad (proyectos MAT2013-42473-R y MAT2013-41723-R

Monte-Carlo simulations of the two-dimensional NMR T2-T2 exchange of fluids in porous media

The effects of molecular exchange processes on the two-dimensional (2D) NMR T2-T2 distributions obtained by Laplace inversion were studied by numerical simulations. The Monte–Carlo technique is used to generate free random walks of a large number of molecules within space regions characterized by different relaxation times. Molecular exchange processes are considered during CPMG encoding periods as well as during the storage period, τstore. Systematic simulations were performed as function of NMR parameters like the storage period, τstore and geometric or physical system properties

Thermodynamic Parameters of Temperature-Induced Phase Transition for Brushes onto Nanoparticles: Hydrophilic versus Hydrophobic End-Groups Functionalization

Quantification of the stimuli-responsive phase transition in polymers is topical and important for the understanding and development of novel stimuli-responsive materials. The temperature-induced phase transition of poly(N-isopropylacrylamide) (PNIPAm) with one thiol end group depends on the confinement—free polymer or polymer brush—on the molecular weight and on the nature of the second end. This paper describes the synthesis of heterotelechelic PNIPAm of different molecular weights with a thiol end group—that specifically binds to gold nanorods and a hydrophilic NIPAm end group by reversible addition-fragmentation chain-transfer polymerization. Proton high-resolution magic angle sample spinning NMR spectra are used as an indicator of the polymer chain conformations. The characteristics of phase transition given by the transition temperature, entropy, and width of transition are obtained by a two-state model. The dependence of thermodynamic parameters on molecular weight is compared for hydrophilic and hydrophobic end functional-free polymers and brushes

STRUCTURAL INVESTIGATION OF SOME NATIVE BIODEGRADABLE PACKAGING MATERIALS

The IR, Raman and NMR methods are used to investigate the structural effects of water and glycerol (plasticizers) on biodegradable packaging materials proceeding from native corn starch. The IR and Raman methods not give a clear response on the amorphous/crystalline content in the investigated starch samples because the origin of vibrational bands is in the same atomic groups of the major starch components (amylose, amylopectin). The nuclear magnetic relaxation data show that the amorphous/crystalline ratio depends not only by the amylose/amylopectin content but also of the mobility and the place of theirs polymer chain segments. The shapes of 13C CP/MAS NMR spectra show clearly the presence of A, B, V-types crystalline structures and also amorphous phase which prevails with the increasing of plasticizers content and also in the extruded starch samples. The composition having starch/glycerol/water 68/17/15 mass % ratio was found to have a dominant amorphous character and very similar features with a commercial specimen (USA) used for the package. It was also found that this best package is extremely degraded after just one day under water absorption

Laplace inversions applied to multi–component T 2 – T 2 exchange experiments

Two-dimensional (2D) T2-T2 molecular exchange NMR experiments with a period of magnetization storage between the two T2 relaxation encoding periods are presented. The two-dimensional time map was inverted using a fast Laplace algorithm to obtain the T2–T2 exchange map. T2–MZ(store)–T2 2D 1H NMR spectra recorded at high and low homogeneous magnetic fields of water and oil in sand, air bubbles in water and foams, exchange of liquid / foam and liquid / saturated vapours of chloroform are presented. Uni– and bi–directional exchange was observed for bubbles in water, superficial liquid shell, and foam

Analysis of Barriers to the Development of Industrial Internet of Things Technology and Ways to Overcome Them

The development of the digital economy requires the compilation of a roadmap for the development of all the end-to-end technologies included in the cluster of technologies that need to be developed to a new level. At the first stage, anticipating decisions on state financing of this cluster, a list of critical end-to-end technologies is compiled. The second step is the preparation of roadmaps for each of the selected critical technologies. As a rule, many experts are involved in drawing up roadmaps, including foreign experts. As a rule, the team of such experts is headed by an organization that has received instructions to develop a roadmap on a competitive basis. Of course, not all the wishes of all experts are taken into account by such an organization; therefore, there may be alternative opinions and alternative roadmaps, or additions to the developed roadmaps. If the roadmap developed by the governing organization is approved, alternative documents are only of perhaps scientific interest. If the roadmap developed by the core team of experts is not approved due to its insufficient completeness, the decision seems to be postponed, and the specified roadmap should be corrected by adding information from alternative documents, which, of course, should be done taking into account the opinion of all experts in the field. Since the approved roadmap for the "Industrial Internet of Things" direction does not yet exist, the authors consider it useful to present their position on this issue