In this paper, the design and research of a sensor-based personal air-quality monitoring device are presented, which is retrofitted into different personal protective face masks. Due to its small size and low power consumption, the device can be integrated into and applied in practical urban usage. We present our research and the development of the sensor node based on a BME680-type environmental sensor cluster with a wireless IoT (Internet of Things)-capable central unit and overall low power consumption. The integration of the sensor node was investigated with traditional medical masks and a professional FFP2-type mask. The filtering efficiency after embedding was validated with a head model and a particle counter. We found that the professional mask withstood the embedding without losing the protective filtering aspect. We compared the inner and outer sensor data and investigated the temperature, pressure, humidity, and AQI (Air Quality Index) relations with possible sensor data-fusion options. The novelty is increased with the dual-sensor layout (inward and outward). It was found that efficient respiration monitoring is achievable with the device. With the analysis of the recorded data, characteristic signals were identified in an urban environment, enabling urban altimetry and urban zone detection. The results promote smart city concepts and help in endeavors related to SDGs (Sustainable Development Goals) 3 and 11.
- Keywords
- IoT, air quality, embedded electronics, face mask, sensors, wearable,
- Publication type
- Journal Article MeSH
Low voltage electron microscopes working in transmission mode, like LVEM5 (Delong Instruments, Czech Republic) working at accelerating voltage 5 kV or scanning electron microscope working in transmission mode with accelerating voltage below 1 kV, require ultrathin sections with the thickness below 20 nm. Decreasing of the primary electron energy leads to enhancement of image contrast, which is especially useful in the case of biological samples composed of elements with low atomic numbers. As a result treatments with heavy metals, like post-fixation with osmium tetroxide or ultrathin section staining, can by omitted. The disadvantage is reduced penetration ability of incident electrons influencing the usable thickness of the specimen resulting in the need of ultrathin sections of under 20 nm thickness. In this study we want to answer basic questions concerning the cutting of extremely ultrathin sections: Is it possible routinely and reproducibly to cut extremely thin sections of biological specimens embedded in commonly used resins with contemporary ultramicrotome techniques and under what conditions? Microsc. Res. Tech. 79:512-517, 2016. © 2016 Wiley Periodicals, Inc.
- Keywords
- low voltage electron microscopy, resin embedding, ultramicrotomy, ultrathin sectioning,
- MeSH
- Equipment Design MeSH
- Microscopy, Electron instrumentation methods MeSH
- Epoxy Resins chemistry MeSH
- Microtomy methods MeSH
- Myocardium ultrastructure MeSH
- Mice MeSH
- Polymers chemistry MeSH
- Heart diagnostic imaging MeSH
- Plastic Embedding methods MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Epoxy Resins MeSH
- Polybed 812 MeSH Browser
- Polymers MeSH
- spurr resin MeSH Browser
High pressure high temperature (HPHT) nanodiamonds (NDs) represent extremely promising materials for construction of fluorescent nanoprobes and nanosensors. However, some properties of bare NDs limit their direct use in these applications: they precipitate in biological solutions, only a limited set of bio-orthogonal conjugation techniques is available and the accessible material is greatly polydisperse in shape. In this work, we encapsulate bright 30-nm fluorescent nanodiamonds (FNDs) in 10-20-nm thick translucent (i.e., not altering FND fluorescence) silica shells, yielding monodisperse near-spherical particles of mean diameter 66 nm. High yield modification of the shells with PEG chains stabilizes the particles in ionic solutions, making them applicable in biological environments. We further modify the opposite ends of PEG chains with fluorescent dyes or vectoring peptide using click chemistry. High conversion of this bio-orthogonal coupling yielded circa 2000 dye or peptide molecules on a single FND. We demonstrate the superior properties of these particles by in vitro interaction with human prostate cancer cells: while bare nanodiamonds strongly aggregate in the buffer and adsorb onto the cell membrane, the shell encapsulated NDs do not adsorb nonspecifically and they penetrate inside the cells.
- Keywords
- biocompatibilization, fluorescent nanodiamonds, nanoparticles,
- MeSH
- Biocompatible Materials chemistry MeSH
- Electrons MeSH
- Fluorescent Dyes chemistry MeSH
- Microscopy, Confocal MeSH
- Humans MeSH
- Luminescence MeSH
- Cell Line, Tumor MeSH
- Nanodiamonds chemistry ultrastructure MeSH
- Silicon Dioxide chemistry MeSH
- Polyethylene Glycols chemistry MeSH
- Spectrophotometry, Infrared MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Biocompatible Materials MeSH
- Fluorescent Dyes MeSH
- Nanodiamonds MeSH
- Silicon Dioxide MeSH
- Polyethylene Glycols MeSH
The in situ combination of plasma-enhanced chemical vapor deposition (PECVD) and vacuum evaporation in the same vacuum chamber allowed us to integrate germanium nanocrystals (Ge NCs) into hydrogenated amorphous silicon carbide (a-SiC:H) thin films deposited from monomethyl silane diluted with hydrogen. Transmission electron microscopy (TEM) and energy-dispersive X-ray (EDX) spectroscopy were used for the microscopic characterization, while photothermal deflection spectroscopy (PDS) and near-infrared photoluminescence spectroscopy (NIR PL) were for optical characterization. The presence of Ge NCs embedded in the amorphous a-Si:C:H thin films was confirmed by TEM and EDX. The embedded Ge NCs increased optical absorption in the NIR spectral region. The quenching of a-SiC:H NIR PL due to the presence of Ge indicates that the diffusion length of free charge carriers in a-SiC:H is in the range of a few tens of nm, an order of magnitude less than in a-Si:H. The optical properties of a-SiC:H films were degraded after vacuum annealing at 550 °C.
The described method of embedding of bacterial colonies into media used for electron microscopy allows the precise orientation of the material for the preparation of ultrathin sections. The colonies are covered by a strip of agar joined to the agar-layer with the cultivated colonies by means of a heated razor-blade. This method is especially useful for ultrastructural studies of L-colonies.
- MeSH
- Bacteriological Techniques * MeSH
- Methods MeSH
- Publication type
- Journal Article MeSH
Adsorption is the most efficient technique for the removal of metal ions and organic dyes from water. This stimulates demand for the preparation of eco-friendly adsorbents. In this study, magnetic hydrogels based on a crosslinked carboxymethyl cellulose grafted acrylamide (CMC-g-AM) embedded with porous carbon (PC) and citric acid-modified magnetite were prepared. PC was synthesized via single-step oxidation of bagasse under muffled atmosphere condition. The magnetite (Fe3O4) nanoparticles were synthesized using the co-precipitation method (Fe2+/Fe3+) and citric acid modification (CFe). Functionality and parameters of adsorbent were characterized by infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray. The magnetic hydrogels have a highly effective performance for Pb-ions and methylene blue dye (MB) removal from water due to the unique role of crosslinked CMC matrix in supporting synergy between embedded PC and CFe. Adsorption testing using time intervals (5-120 min) and Pb-ions and MB concentrations (5-500 mg/L) indicate that CMC-g-AM containing equal content of PC and CFe has substantially higher removal efficiency; 70.8 and 96.1 % against 47.8 and 30.2 % (without PC and CFe) for Pb-ions and MB adsorption respectively for CMC-g-AM. The equilibrium time and the maximum sorption capacity (qm) from the adsorption studies were found to be 60 and 30 min and 294.1 and 222.2 mg/g for Pb-ions and MB respectively. The kinetics and isotherms were studied to highlight the adsorption rate and mechanism of the adsorption process.
- Keywords
- Hydrogel, Magnetite, carboxymethyl cellulose, Metal and dye adsorption, Porous carbon,
- Publication type
- Journal Article MeSH
Rational design of metal single-site embedded porous graphitic carbon nitride (P-g-C3N4) nanostructures exploiting maximum atom utilization is warranted to enhance the thermal CO oxidation (COOx) reaction. Herein, a facile, green, one-pot, and template-free approach is developed to fabricate the hierarchical porous P-g-C3N4-crumpled ultrathin nanosheets atomically doped with copper single atoms (Cu-P-g-C3N4). Mechanistically, the quick protonation of melamine and pyridine under acidic conditions induces deamination to form melem, which is polycondensed under heating. The interconnected pores, high surface area (240 m2g-1), and maximized exposed isolated Cu atomic active sites (1.8 wt %) coordinated with nitrogen atom P-g-C3N4 are the salient features of Cu- P-g-C3N4 that endowed complete conversion to CO2 at 184 °C. In contrast, P-g-C3N4 only converted 3.8% of CO even at 350 °C, implying the electronic effect of Cu single atoms. The abundant Cu-nitrogen moieties can drastically weaken the binding affinity of the CO-oxidation (COOx) intermediates and products, thus accelerating the reaction kinetics at a low temperature. This study may promote the fabrication of P-g-C3N4 doped with various single atoms for the oxidation of CO.
- Keywords
- CO oxidation, CO oxidation reaction mechanism, Cu single site, carbon nitride, porous g-C3N4,
- Publication type
- Journal Article MeSH
A protocol for high-pressure freezing and LR White embedding of mammalian cells suitable for fine ultrastructural studies in combination with immunogold labelling is presented. HeLa S3 cells enclosed in low-temperature gelling agarose were high-pressure frozen, freeze-substituted in acetone, and embedded in LR White at 0 degrees C. The morphology of such cells and the preservation of nuclear antigens were excellent in comparison with chemically fixed cells embedded in the same resin. The immunolabelling signal for different nuclear antigens was 4-to-13 times higher in high-pressure frozen than in chemically fixed cells. We conclude that one can successfully use high-pressure freezing/freeze-substitution and LR White embedding as an alternative of Lowicryl resins.
- MeSH
- Acrylic Resins * MeSH
- Antigens, Nuclear analysis MeSH
- Cell Nucleus immunology ultrastructure MeSH
- HeLa Cells MeSH
- Immunohistochemistry MeSH
- Cryopreservation methods MeSH
- Humans MeSH
- Freeze Substitution * MeSH
- Pressure MeSH
- Microscopy, Electron, Transmission MeSH
- Plastic Embedding methods MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Acrylic Resins * MeSH
- Antigens, Nuclear MeSH
- LR white MeSH Browser
The embedding of caffeate methyl ester, the flavonoids luteolin and quercetin, and the o-phenanthroline and neocuproine in a liquid disordered lipid bilayer has been studied through extensive atomistic calculations. The location and the orientation of these bio-active antioxidants are explained and analyzed. While the two phenanthrolines strongly associate with the lipid tail region, the other three compounds are rather found among the head groups. The simulations showcase conformational changes of the flavonoids. Through the use of a hybrid quantum mechanics-molecular mechanics scheme and supported by a profound benchmarking of the electronic excited-state method for these compounds, the influence of the anisotropic environment on the compounds' optical properties is analyzed. Influences of surrounding water molecules and of the polar parts of the lipids on the transition dipole moments and excited-state dipole moments are weighted with respect to a change in conformation. The current study highlights the importance of the mapping of molecular interactions in model membranes and pinpoints properties, which can be biomedically used to discriminate and detect different lipid environments.
- MeSH
- Antioxidants MeSH
- Coloring Agents * MeSH
- Phenanthrolines * MeSH
- Flavonoids MeSH
- Lipid Bilayers chemistry MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Antioxidants MeSH
- Coloring Agents * MeSH
- Phenanthrolines * MeSH
- Flavonoids MeSH
- Lipid Bilayers MeSH
Hydrogel based matrices and titanium dioxide (TiO2) nanoparticles (NPs) are well established materials in bone tissue engineering. Nevertheless, there is still a challenge to design appropriate composites with enhanced mechanical properties and improved cell growth. Progressing in this direction, we synthesized nanocomposite hydrogels by impregnating TiO2 NPs in a chitosan and cellulose-based hydrogel matrix containing polyvinyl alcohol (PVA), to enhance the mechanical stability and swelling capacity. Although, TiO2 has been incorporated into single and double component matrix systems, it has rarely been combined with a tri-component hydrogel matrix system. The doping of NPs was confirmed by Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy and small- and wide-angle X-ray scattering. Our results showed that incorporation of TiO2 NPs improved the tensile properties of the hydrogels significantly. Furthermore, we performed biological evaluation of scaffolds, swelling degree, bioactivity assessment, and hemolytic tests to prove that all types of hydrogels were safe for use in the human body. The culturing of human osteoblast-like cells MG-63 on hydrogels showed better adhesion of cells in the presence of TiO2 and showed increasing proliferation with increasing amount of TiO2. Our results showed that the sample with the highest TiO2 concentration, CS/MC/PVA/TiO2 (1 %) had the best biological properties.
- Keywords
- Biological evaluation, Bone tissue engineering, Chitosan, Microcrystalline cellulose, Nanocomposite hydrogel, Scaffold, Titanium dioxide,
- MeSH
- Cellulose pharmacology MeSH
- Chitosan * pharmacology chemistry MeSH
- Hydrogels pharmacology chemistry MeSH
- Humans MeSH
- Nanoparticles * chemistry MeSH
- Polyvinyl Alcohol chemistry MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Cellulose MeSH
- Chitosan * MeSH
- Hydrogels MeSH
- Polyvinyl Alcohol MeSH
- titanium dioxide MeSH Browser
