Towards Organic Zeolites and Inclusion Catalysts: Heptazine Imide Salts Can Exchange Metal Cations in the Solid State

Highly crystalline potassium (heptazine imides) were prepared by the thermal condensation of substituted 1,2,4- triazoles in eutectic salt melts. These semiconducting salts are already known to be highly active photocatalysts, e.g. for the visible light driven generation of hydrogen from water. Herein, we show that within the solid state structure, potassium ions can be exchanged to other metal ions while the crystal habitus is essentially preserved

Protein-Coated Magnetic Nanoparticles: Creation and Investigation

A novel universal approach to cross-linking of protein macromolecules on the surface of magnetite na-noparticles has been developed. The approach is based on protein liability to free radical modification, leading to the formation of intermolecular covalent cross links. Free radicals are locally generated on the surface of nanoparticles. Using a set of physicochemical methods, it has been proven that stable coatings composed of protein macromolecules are formed around individual nanoparticles. The proteins fixed on nanoparticles do not lose their activity as a result of adsorption and free radical modification. Fluorescent probe approach for evaluation of the native functional properties of serum albumin as a part of coating is suggested. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3537

Electrooxidation of formic acid on gold : An ATR-SEIRAS study of the role of adsorbed formate

Funding from the DGI (Spanish Ministry of Education and Science) through Projects CTQ2009-07017 and PLE2009-0008 is gratefully acknowledged. M.E.-E. acknowledges an FPI fellowship from the Spanish Ministry of Science and Innovation and an accommodation grant at the Residencia de Estudiantes from the Madrid City Council. C. V.-D. acknowledges a JAE-Doc fellowship from CSIC.Peer reviewedPostprin

The impact of video-based virtual reality training on critical thinking and cognitive load

Online learning, including in higher education, is an active part of the modern educational landscape. Spherical video-based immersive virtual reality (SV-IVR) is useful in this field. This study aimed to determine the impact of teaching with the use of SV-IVR on the critical thinking and cognitive load of 140 students. The findings of the study revealed that students exhibited low levels of mental effort and mental load based on the observed indicators. Compared to the traditional teaching method, the SV-IVR model had a better effect on improving students' critical thinking skills. The findings can help teachers develop new learning models using video-based virtual reality

Ophthalmic products with extracellular matrix components. Their effectiveness in the process of corneal repair in neurotrophic, herpetic, recurrent keratitis and erosions

Introduction. One of the topical issues of modern ophthalmology is the widespread prevalence of corneal blindness among the working-age population. The cause of this condition in most cases are infectious and inflammatory diseases of the anterior segment of the eye, the outcome of which is a violation of the architectonics of the extracellular matrix (ECM) of the cornea, clinically manifested by edema of the stroma, its fibrosis. Purpose. Comparative analysis of the effectiveness of existing ophthalmic agents based on biomimetics of ECM to stimulate the processes of reparative regeneration in neurotrophic, herpetic, recurrent keratitis and corneal erosions. Material and methods. Our literature review has shown the great importance of thecomponents in maintaining corneal homeostasis, its transparency, strength, shape stability, as well as differentiation, proliferation, migration and growth of cellular structures of the ECM, and therefore the need to maintain its physiological architectonics in the treatment of infectious and inflammatory pathology. Results. The range of ophthalmic medicines and medical devices based on biomimetics of ECM is quite diverse. The active substances of such ophthalmic agents are the main components of the ECM, namely, glycosaminoglycans (GAG), glycoproteins, collagen, hyaluronic acid, heparin. Conclusion. Among the many biomimetics, we can single out the multicomponent hydrogel composition «Corneal Epithelium gel Protector (CEGP) SPHERO®oko (JSC «BIOMIR Service», Russia), designed to restore the corneal epithelium, which includes both the main components of ECM and other biologically active substances, including peptides, amino acids, uronic acids, monosaccharides, growth factors, etc. The multicomponent composition of SPHERO®oko provides the microenvironment necessary for the cells of the eye tissues, contributing to the processes of their proliferation and differentiation and, as a final result, to the acceleration of reparative regeneration of tissues damaged as a result of injury or infectious-inflammatory process. And also SPHERO®oko demonstrates anti-inflammatory, decongestant, tear-substituting action, contributes to reducing neovascularization

Nanohybrid biosensor based on mussel-inspired electro-cross-linking of tannic acid capped gold nanoparticles and enzymes

Complementary tools to classical analytical methods, enzymatic biosensors are widely applied in medical diagnosis due to their high sensitivity, potential selectivity, and their possibility of miniaturization/automation. Among the different protocols of enzyme immobilization, the covalent binding and cross-linking of enzymes ensure the great stability of the developed biosensor. Obtained manually by drop-casting using a specific cross-linker, this immobilization process is not suitable for the specific functionalization of a single electrode out of a microelectrode array. In the present work, we developed a nanohybrid enzymatic biosensor with high sensitivity by a mussel-inspired electro-cross-linking process using a cheap and abundant natural molecule (tannic acid, TA), gold salt, and native enzymes. Based on the use of a cheap natural compound and gold salt, this electro-cross-linking process based on catechol/amine reaction (i) is versatile, likely to be applied on any kind of enzymes, (ii) does not require the synthesis of a specific cross-linker, (ii) gives enzymatic biosensors with high and very stable sensitivity over two weeks upon storage at room temperature and (iv) is temporally and spatially controlled, allowing the specific functionalization of a single electrode out of a microelectrode array. Besides the development of microbiosensors, this process can also be used for the design of enzymatic biofuel cells

Triazoles : a new class of precursors for the synthesis of negatively charged carbon nitride derivatives

Carbon nitride polymers were prepared for the first time by the pyrolysis of 3,5-disubstituted-1,2,4-triazole derivatives, namely 3,5-diamino-1,2,4-triazole [1] and 3-amino-1,2,4-triazole-5-thiol [2], in bulk as well as in LiCl/KCl salt melts. The reaction of [1] and [2] in bulk yields condensed heptazine-based polymers, while in LiCl/KCl eutectics it leads to the formation of well-defined potassium poly(heptazine imides), according to the results of 13C NMR and XPS investi-gations, whose formation resembles that of emeraldine salts of polyaniline. The density functional calculations supported the structural model suggested for potassium poly(heptazine imide) polymer. Owing to the specific reaction path, the products obtained from triazoles therefore show electronic properties rather different to known carbon nitrides, such as band gap and conduction and valence bands positions. With the degree of crystallinity of the reference materials, triazole-derived carbon nitrides are characterized by almost complete absence of steady photoluminescence, charge separation and localization upon excitation seems to be improved. As a consequence, photocatalysts prepared from [2] outperform classical carbon nitrides in a model dye degradation reaction and mesoporous graphitic carbon nitride in hydrogen evolution reaction under visible light irradiation. On its turn, [1] can be conveniently used as a co-monomer in order to prepare carbon nitrides with improved visible light absorption

One step synthesis of niobium doped titania nanotube arrays to form (N,Nb) co-doped TiO 2 with high visible light photoelectrochemical activity

International audienceThe chemical modification of aligned titanium dioxide nanotube (TiO2-NT) arrays provides new doping possibilities to improve their photoelectrochemical activity under visible light. Niobium doped TiO2-NTs containing up to 15% of Nb in the near-surface region are prepared by a flexible single step procedure using a fluoroniobate complex simultaneously acting as a source of the doping element and fluoride anions required for nanotube formation. This negatively charged complex allows an efficient insertion of Nb in the forming TiO2-NT structure during the anodization process. These nanotube arrays are further modified with nitrogen to achieve (Nb,N) co-doped nanotubes with noticeable visible light photoelectrochemical activity