Prototype of an opto-capacitive probe for non-invasive sensing cerebrospinal fluid circulation

In brain studies, the function of the cerebrospinal fluid (CSF) awakes growing interest, particularly related to studies of the glymphatic system in the brain, which is connected with the complex system of lymphatic vessels responsible for cleaning the tissues. The CSF is a clear, colourless liquid including water (H2O) approximately with a concentration of 99 %. In addition, it contains electrolytes, amino acids, glucose, and other small molecules found in plasma. The CSF acts as a cushion behind the skull, providing basic mechanical as well as immunological protection to the brain. Disturbances of the CSF circulation have been linked to several brain related medical disorders, such as dementia. Our goal is to develop an in vivo method for the non-invasive measurement of cerebral blood flow and CSF circulation by exploiting optical and capacitive sensing techniques simultaneously. We introduce a prototype of a wearable probe that is aimed to be used for long-term brain monitoring purposes, especially focusing on studies of the glymphatic system. In this method, changes in cerebral blood flow, particularly oxy- and deoxyhaemoglobin, are measured simultaneously and analysed with the response gathered by the capacitive sensor in order to distinct the dynamics of the CSF circulation behind the skull. Presented prototype probe is tested by measuring liquid flows inside phantoms mimicking the CSF circulation

Small AgNP in the Biopolymer Nanocomposite System

In this work, ultra-small and stable silver nanoparticles (AgNP) on chitosan biopolymer (BP/AgP) were prepared by in situ reduction of the diamminesilver(I) complex ([Ag(NH3)2]+) to create a biostatic membrane system. The small AgNP (3 nm) as a stable source of silver ions, their crystal form, and homogeneous distribution in the whole solid membrane were confirmed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The X-ray photoelectron spectroscopy (XPS) and Auger analysis were applied to investigate the elemental composition, concentration, and chemical state of surface atoms. It was found that ultra-small metallic nanoparticles might form a steady source of silver ions and enhance the biostatic properties of solid membranes. Ultra-small AgNP with disturbed electronic structure and plasmonic properties may generate interaction between amine groups of the biopolymer for improving the homogeneity of the nanometallic layer. In this work, the significant differences between the typical way (deposition of ex-situ-prepared AgNP) and the proposed in-situ synthesis approach were determined. The improved thermal stability (by thermogravimetry and differential scanning calorimetry (TG/DSC) analysis) for BP/AgP was observed and explained by the presence of the protective layer of a low-molecular silver phase. Finally, the antibacterial activity of the BP/AgP nanocomposite was tested using selected bacteria biofilms. The grafted membrane showed clear inhibition properties by destruction and multiple damages of bacteria cells. The possible mechanisms of biocidal activity were discussed, and the investigation of the AgNP influence on the bacteria body was illustrated by AFM measurements. The results obtained concluded that the biopolymer membrane properties were significantly improved by the integration with ultra-small Ag nanoparticles, which added value to its applications as a biostatic membrane system for filtration and separation issues

Synthesis of new mesostructured cellular foams (MCFs) with NaY zeolite and their application to sorption of thorium ions

The paper presents the new way of preparation of MCF foams with NaY zeolite. Significant changes in the amount of micro and mesopores in relation to the amount of NaY zeolite and 1,3,5-trimethylbenzene (TMB) added during the synthesis was observed. It suggests the possibility of controlling the micro/mesopores ratio by applying the proposed method. Environmental aspects of using new MCF/NaY foams is related to the adsorption of thorium ions (Th+4). The term of “MCF/NaY materials” refers to the general name of the material without referring to the content and state of zeolite. The obtained materials were highly effective in relation to Th+4. The adsorption capacity was greater when the number of micropores was lower. The dependence of adsorption capacity of Th+4 ions on aluminum atoms content was also confirmed

Actual challenges, opportunities, and perspectives of composite materials

The development of technology is associated with a strong need for changes in the design and manufacture of new types of materials. Monolithic materials such as ceramics or metals have become insufficient for the needs of the modern market. The combination of several types of materials in one system turned out to be the right solution. Composite materials as multi-phase materials show improved properties compared with individual structural elements and can give the opportunity to design systems with enhanced specific characteristics.The presented work provides a review of actual literature dedicated to composite materials. In this work, the basic terminology, the division of composite systems, the most commonly used methods for composites preparation as well as physicochemical characteristics and potential applications of these types of matter were presented

Mimetics of manganese catalase as synthetic antioxidants

The coordination chemistry of manganese complexes with heteroaromatic ligands have received considerable attention in modern inorganic chemistry due to its wide range of applications. One of them is related with its potential biological role associated with prevention of oxidative stress injuries. Manganese complexes are one of the most versatile and interesting synthetic systems that can act as artificial mimics of manganese-containing metalloenzymes such as manganese catalase (Mn-CAT). Due to the potential use as catalytic scavengers of H2O2, numerous and diverse, very structurally interesting Mn compounds exhibiting CAT-like activity have been reported so far. In this short review, the relevant features of both, structural, as well as, functional mimics of manganese catalase and their CAT-like activity are presented and some insights into the role of the bridging ligands, endogenous bases, and first- and second-sphere effects on the catalysis are discussed

Physicochemical and Adsorption Characteristics of Divinylbenzene-co-Triethoxyvinylsilane Microspheres as Materials for the Removal of Organic Compounds

In this work, organic-inorganic materials with spherical shape consisting of divinylbenzene (DVB) and triethoxyvinylsilane (TEVS) were synthesized and investigated by different complementary techniques. The obtained microspheres may be applied as sorbent systems for the purification of organic compounds from water. The hybrid microspheres combine the properties of the constituents depending on the morphologies and interfacial bonding. In this work, the influence of the molar ratio composition of crosslinked monomer (DVB) and silane coupling agent (TEVS) (DVB:TEVS molar ratios: 1:2, 1:1 and 2:1) on the morphology and quality of organic-inorganic materials have been examined. The materials were analysed using small angle X-ray scattering (SAXS) analysis, low-temperature nitrogen sorption, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) to provide information on their structural and surface properties. Moreover, thermal analysis was performed to characterize the thermal stability of the studied materials and the adsorbent-adsorbate interactions, while adsorption kinetic studies proved the utility of the synthesized adsorbents for water and wastewater treatment

Novel eight-coordinated Cd(II) complexes with two homologous pyridine alcohols : crystal structure, spectroscopic and thermal properties

Two novel cadmium(II) complexes with homologous pyridine alcohols: [Cd(2-MeOHPy) 2 (NO 3 ) 2 ]( 1 ) and [Cd(2-EtOHPy) 2 (NO 3 ) 2 ]( 2 ) have been prepared and characterized by elemental analysis, X-ray crystallo- graphic studies, spectroscopic (IR, 1 H and 13 C NMR) and thermal properties. IR, NMR and X-ray analysis have confirmed a bidentate fashion of coordination of heteroaromatic alcohols with Cd(II) ions. 2-MeO- HPy bound directly to the central ion by N, O-donor atoms giving five-membered chelate ring but 2- EtOHPy formed less stable six-membered chelate ring. In the complex ( 1 ) and ( 2 ) bidentate nitrate ligands are arranged in cis position for organic ligands. In both cases cadmium(II) ions are eight-coordi- nated and shape of coordination polyhedral can be described as pseudo-dodecahedron (CdN 2 O 6 chromo- phore type). The crystal packing of Cd(II) complexes are stabilized by intermolecular classical hydrogen bonds of O A H O and non-classical C A H O type. In addition, there are p – p stacking interactions between almost parallel-displaced pyridine rings of 2-hydroxymethylpyridine in the two neighbouring complex ( 1 ) molecules but the hydrogen interactions in ( 2 ) are formed by C A H donor group of Py rings and p -electron system of neighbouring one

Thermal behavior of manganese(II) complexes with pyridine-2,3-dicarboxylic acid

In this study, we analyzed influence of the type of the syntheses used: hydrothermal and non-hydrothermal on pyridine-2,3-dicarboxylic acid (2,3pydcH 2 ) coordina- tion fashion. Two manganese(II) complexes: [Mn(H 2 O) 3 (2,3pydc)] n ( 1 ) and [Mn(H 2 O) 6 ][Mn(2,3pydcH) 3 ] 2 ( 2 ) were successfully synthesized from the non-hydrothermal reac- tion system containing organic ligand and different Mn(II) salts. The received complexes have been prepared and characterized by spectroscopic (IR, Raman), structural (X-ray single crystal), and thermogravimetric methods. The results of the crystal study give some evidence that ligand exhibits various topological structures and interest- ing properties. Pyridine-2,3-dicarboxylic acid acts as monodicarboxylate N,O-chelating anion (complex 2 )ora doubly deprotonated three-dentate- N , O , O 0 dicarboxylate ion (complex 1 ). In the [Mn(H 2 O) 6 ][Mn(2,3pydcH) 3 ] 2 the coordination geometry around Mn(1) ion can be considered as being distorted octahedron {MnN 3 O 3 }. The Mn(2) cat- ion possesses the same coordination polyhedron (octahe- dral). We have also analyzed influence of furnace atmosphere on the thermal behavior and the kind of final product. The sample of ( 1 ) decomposes in four stages in N 2 (368–1073 K) and the final residue is MnO 2 . The ther- mogram of ( 2 ) exhibits three main distinct decomposition steps (383–973 K). A residue of MnO is remained. In both air and nitrogen atmosphere, Mn(II) complexes ( 1 ) and ( 2 ) keep unchanged over all steps of decomposition. Only the final residues are different (Mn 2 O 3 are formed). The course of pyrolysis and molecular structure of the complexes lead to the same conclusion about the strength of metal–ligand bonds. On the basis of the above results, it is concluded that the thermal stability of the manganese(II) compounds is slightly different