Exploring tear viscosity with quartz crystal microbalance technology.

Tear viscosity is a critical property affecting tear distribution and ocular surface stability. While not widely established as a primary diagnostic marker, deviations from normal viscosity can impact ocular health, potentially contributing to conditions such as dry eye syndrome. Despite their importance, traditional viscometers require sample volumes that are not feasible to use with tear volume.

Acidity of Isomorphic Substituted Zeolites with B, Al and Ga Revisited.

Isomorphic substitution of zeolites with B, Al and Ga is a widely used approach in catalysis. The experimentally reported trend of their acidities decreases in the order: Al>Ga>B. However, a consistent explanation is still lacking in the literature.

Unveiling the mechanisms of carboxylic acid esterification on acid zeolites for biomass-to-energy: A review of the catalytic process through experimental and computational studies.

In recent years, there has been significant interest from industrial and academic areas in the esterification of carboxylic acids catalyzed by acidic zeolites, as it represents a sustainable and economically viable approach to producing a wide range of high-value-added products. However, there is a lack of comprehensive reviews that address the intricate reaction mechanisms occurring at the catalyst interface at both the experimental and atomistic levels. Therefore, in this review, we provide an overview of the esterification reaction on acidic zeolites based on experimental and theoretical studies.

Micro-thermography for imaging ice crystal growth and nucleation inside non-transparent materials.

Ice crystal growth and nucleation rate measurements are usually done using light microscopy in liquid and transparent samples. Yet, the understanding of important practical problems depends on monitoring ice growth inside solid materials, for example how rapid ice growth leads to structural damage of food, or how the final structure of cementitious materials is affected by ice during curing. Imaging crystal growth inside solid materials cannot be done with visible light and is intrinsically more challenging than visible light imaging.

Quartz crystal Microbalance with dissipation monitoring for biomedical applications: Open source and low cost prototype with active temperature control.

Advances in sensors have revolutionized the biomedical engineering field, having an extreme affinity for specific analytes also providing an effective, real-time, point-of-care testing for an accurate diagnosis. Quartz Crystal Microbalance (QCM) is a well-established sensor that has been successfully applied in a broad range of applications to monitor and explore various surface interactions, in situ thin-film formations, and layer properties. This technology has gained interest in biomedical applications since novel QCM systems are able to work in liquid media.

Validation and adaptation of the Spanish version of the systemic lupus activity questionnaire (S-SLAQ) in an Argentinean population.

Objectives: To validate the systemic lupus activity questionnaire (SLAQ) in Spanish language.

Methods: The SLAQ questionnaire was translated and adapted in Spanish. Consecutive SLE patients from 8 centers in Argentina were included.

Evaluation of the Educational Needs in Argentine Patients with Rheumatoid Arthritis Using the SpENAT Questionnaire.

Background: The SpENAT, a Spanish version of the Educational Needs Assessment Tool, is a self-completed questionnaire that assesses educational needs (ENs) with the purpose of providing tailored and patient-centered information. It consists of 39 questions grouped into the 7 following domains: Pain management, Movement, Feelings, Arthritic process, Treatments, Self-help measures and Support system.

Objectives: The objective of the study was to describe the ENs of rheumatoid arthritis (RA) patients using the SpENAT and to determine the main sources of information consulted by these patients.

Molecular structure of uranium carbides: isomers of UC3.

In this article, the most relevant isomers of uranium tricarbide are studied through quantum chemical methods. It is found that the most stable isomer has a fan geometry in which the uranium atom is bonded to a quasilinear C3 unit. Both, a rhombic and a ring CU(C2) structures are found about 104-125 kJ/mol higher in energy.

On the molecular structure of uranium dicarbide: T-shape versus linear isomers.

A theoretical study of the molecular structure of uranium dicarbide has been carried out employing DFT, coupled cluster, and multiconfigurational methods. A triangular species, corresponding to a (5)A(2) electronic state, has been found to be the most stable UC(2) species. A triplet linear CUC species, which has been observed in recent infrared spectroscopy experiments, lies much higher in energy.

Topological description of the bond-breaking and bond-forming processes of the alkene protonation reaction in zeolite chemistry: an AIM study.

Density functional theory and atoms in molecules theory were used to study bond breakage and bond formation in the trans-2-butene protonation reaction in an acidic zeolitic cluster. The progress of this reaction along the intrinsic reaction coordinate, in terms of several topological properties of relevant bond critical points and atomic properties of the key atoms involved in these concerted mechanisms, were analyzed in depth. At B3LYP/6-31++G(d,p)//B3LYP/6-31G(d,p) level, the results explained the electron density redistributions associated with the progressive bond breakage and bond formation of the reaction under study, as well as the profiles of the electronic flow between the different atomic basins involved in these electron reorganization processes.

Adsorption of alkenes on acidic zeolites. Theoretical study based on the electron charge density.

In the present work, experiments on electron density changes in the adsorption process of alkenes on acidic zeolites, in the framework of atoms in molecules theory (AIM), were carried out. Electron densities were obtained at MP2 and B3LYP levels using a 6-31++G(d,p) basis set. This study explores the energetic and the electron density redistributions associated with O-H.

Theoretical analysis of the electronic properties of the sex pheromone and its analogue derivatives in the female processionary moth Thaumetopoea pytiocampa.

In the present work, the distribution of the electronic charge density of the natural sex pheromone, the (Z)-13-hexadecen-11-ynyl acetate, in the female processionary moth, Thaumetopoea pytiocampa, and its nine analogue derivatives was studied within the framework of the Density Functional Theory and the Atoms in Molecules (AIM) Theory at B3LYP/6-31G *//B3LYP/6-31++G * * level. Additionally, molecular electrostatic potential (MEP) maps of the previously mentioned compounds were computed and compared. Furthermore, the substitution of hydrogen atoms from the methyl group in the acetate group by electron withdrawing substituents (i.

Topological analysis of the electronic charge density in the ethene protonation reaction catalyzed by acidic zeolite.

In the present work, the distribution of the electronic charge density in the ethene protonation reaction by a zeolite acid site is studied within the framework of the density functional theory and the atoms in molecules (AIM) theory. The key electronic effects such as topological distribution of the charge density involved in the reaction are presented and discussed. The results are obtained at B3LYP/6-31G(**) level theory.

Patterns of drug, alcohol and tobacco use among high school students in Santiago, Chile.

A survey using a self-administered questionnaire, based on a sample of 1,240 students from four public schools in Santiago, showed that 70.1 per cent of the students used alcohol, 56.3 per cent tobacco, 7.