Particle engineering
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V první části článku autor podrobně klasifikuje biosignaly z nejrůznějších hledisek Výsledky uvádí v přebiednych tabulkách pro nativní biosignály. Konkrétní příklady jsou zvoleny z růzjtých klinických oborů s cílem ukázat použití biosignálů v současné medicíně a v příbuzných oborech.
In the article the biosignals in detail are classified from various sides of view. The results for native biosignals are presented in lucid tables. The concrete examples are chosen from various clinical branches with goal of showing use of biosignals in present medicine.
This article reviews the development of artificial bone substitutes from their older single-phase forms to novel multi-phase composites, mimicking the composition and architecture of natural bone tissue. The new generation of bone implants should be bioactive, i.e. they should induce the desired cellular responses, leading to integration of the material into the natural tissue and stimulating self-healing processes. Therefore, the first part of the review explains the common principles of the cellmaterial interaction and summarizes the strategies how to improve the biocompatibility and bioactivity of the materials by modifying the physico-chemical properties of the material surface, such as surface chemistry, wettability, electrical charge, rigidity, microroughness and especially nanoroughness. The latter has been shown to stimulate preferentially the growth of osteoblasts in comparison with other competitive cell types, such as fibroblasts, which could prevent fibrous tissue formation upon implantation. The second more specialized part of the review deals with materials suitable for bone contact and substitution, particularly novel polymer-based composites reinforced with fibres or inorganic particles and containing bioactive components, such as crystals of hydroxyapatite or other calcium phosphates, synthetic ligands for cell adhesion receptors or growth factors. Moreover, if they are degradable, they can be gradually replaced with a regenerating tissue.
- MeSH
- biokompatibilní materiály MeSH
- financování organizované MeSH
- kostní náhrady chemie terapeutické užití MeSH
- lidé MeSH
- osteoblasty fyziologie MeSH
- osteogeneze MeSH
- osteointegrace MeSH
- povrchové vlastnosti MeSH
- protézy - design MeSH
- tkáňové inženýrství MeSH
- transplantace kostí přístrojové vybavení MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- přehledy MeSH
Exhaust emissions of 23 individual city buses at Euro III, Euro IV and EEV (Enhanced Environmentally Friendly Vehicle) emission levels were measured by the chasing method under real-world conditions at a depot area and on the normal route of bus line 24 in Helsinki. The buses represented different technologies from the viewpoint of engines, exhaust after-treatment systems (ATS) and fuels. Some of the EEV buses were fueled by diesel, diesel-electric, ethanol (RED95) and compressed natural gas (CNG). At the depot area the emission factors were in the range of 0.3-21 × 10(14) # (kg fuel)(-1), 6-40 g (kg fuel)(-1), 0.004-0.88 g (kg fuel)(-1), 0.004-0.56 g (kg fuel)(-1), 0.01-1.2 g (kg fuel)(-1), for particle number (EFN), nitrogen oxides (EFNOx), black carbon (EFBC), organics (EFOrg), and particle mass (EFPM1), respectively. The highest particulate emissions were observed from the Euro III and Euro IV buses and the lowest from the ethanol and CNG-fueled buses, which emitted BC only during acceleration. The organics emitted from the CNG-fueled buses were clearly less oxidized compared to the other bus types. The bus line experiments showed that lowest emissions were obtained from the ethanol-fueled buses whereas large variation existed between individual buses of the same type indicating that the operating conditions by drivers had large effect on the emissions.
- MeSH
- látky znečišťující vzduch analýza chemie MeSH
- molekulová hmotnost MeSH
- motorová vozidla * MeSH
- velkoměsta MeSH
- výfukové emise vozidel analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Finsko MeSH
- velkoměsta MeSH
... Yannas XIII -- List of Contributors XIX -- Section I -- Basic Principes, Basic Research 1 -- Tissue Engineering ... ... Vander Kam 37 -- Transfection of Human Keratinocytes in Vitro with the Particle Mediated Gene -- Transfer ... ... Ehrlich 83 -- Multiple Applications of Tissue-Engineered Human Skin -- L. Germain, V. Moulin, F. ... ... Auger. 91 -- Fibrin Microbeads (FMB) for Wound Healing and Tissue Engineering of Skin -- R. ... ... A Navsaria 117 -- Keratinocyte Growth Factor (KGF): Its Possible Use in Tissue Engineering -- E. E. ...
xxxi, 363 s. : il. ; 25 cm
- MeSH
- biomedicínské inženýrství MeSH
- keratinocyty MeSH
- techniky tkáňových kultur MeSH
- umělá kůže MeSH
- Publikační typ
- monografie MeSH
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- biomedicínské inženýrství
- dermatovenerologie
- transplantologie
The present study was performed to identify possible genotoxicity induced by organic extracts from particulate matter in the exhaust of two typical diesel engines run on diesel fuel and neat heated fuel-grade rapeseed oil: a Cummins ISBe4 engine tested using the World Harmonized Steady State Test Cycle (WHSC) and modified Engine Steady Cycle (ESC) and a Zetor 1505 engine tested using the Non-Road Steady State Cycle (NRSC). In addition, biodiesel B-100 (neat methylester of rapeseed oil) was tested in the Cummins engine run on the modified ESC. Diluted exhaust was sampled with high-volume samplers on Teflon coated filters. Filters were extracted with dichlormethane (DCM) and DNA adduct levels induced by extractable organic matter (EOM) in an acellular assay of calf thymus DNA coupled with (32)P-postlabeling in the presence and absence of rat liver microsomal S9 fraction were employed. Simultaneously, the chemical analysis of 12 priority PAHs in EOM, including 7 carcinogenic PAHs (c-PAHs) was performed. The results suggest that diesel emissions contain substantially more total PAHs than rapeseed oil emissions (for the ESC) or that these concentrations were comparable (for the WHSC and NRSC), while c-PAHs levels were comparable (for the ESC) or significantly higher (for the WHSC and NRSC) for rapeseed oil emissions. DNA adduct levels induced by diesel and rapeseed oil derived EOM were comparable, but consistently slightly higher for diesel than for rapeseed oil. Highly significant correlations were found between 12 priority PAHs concentrations and DNA adduct levels (0.980; p<0.001) and these correlations were even stronger for c-PAHs (0.990; p<0.001). Metabolic activation by the microsomal S9 fraction resulted in several fold higher genotoxicity, suggesting a major contribution of PAHs to genotoxicity. Directly acting compounds, other than c-PAHs, and not requiring S9 to exhibit DNA reactivity were also significant. Generally, DNA adduct levels were more dependent on the type of engine and the test cycle than on the fuel. Our findings suggest that the genotoxicity of particulate emissions from the combustion of rapeseed oil is significant and is comparable to that from the combustion of diesel fuel. A more detailed study is ongoing to verify and extent these preliminary findings.
- MeSH
- adukty DNA analýza MeSH
- benzin toxicita MeSH
- jaterní mikrozomy účinky léků MeSH
- játra účinky léků MeSH
- krysa rodu rattus MeSH
- mutageny analýza MeSH
- neparametrická statistika MeSH
- oleje rostlin chemie toxicita MeSH
- pevné částice chemie toxicita MeSH
- polycyklické aromatické uhlovodíky analýza MeSH
- výfukové emise vozidel analýza toxicita MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
Raman micro-spectroscopy technique offers a combination of relatively high spatial resolution with identification of components or mixtures of components in different sample areas, e.g. on the surface or the cross-section of a sample. This study is focused on the analysis of the tablets from pharmaceutical development with different technological parameters: (1) the manufacturing technology, (2) the particle size of the input API (active pharmaceutical ingredient) and (3) the quantitative composition of the individual excipients. These three mentioned parameters represent the most frequently solved problems in the field of reverse engineering in pharmacy. The investigation aims to distinguish tablets with the above-described technological parameters with limited subjective steps by Raman microscopy. Furthermore, non-subjective methods of Raman data analysis using advanced statistical analysis have been proposed, namely Principal Component Analysis, Soft Independent Modelling of Class Analogy and Linear Discriminant Analysis. The methods successfully distinguished and identified even very small differences in the analysed tablets within our study and provided objective statistic evaluation of Raman maps. The information on component and particle size distribution including their small differences, which is the critical parameter in the development of the original and generic products, was obtained due to combination of these methods. Even though each of these chemometric methods evaluates the data set from a different perspective, their mutual application on the problem of Raman maps evaluation confirmed and specified results on level that would be unattainable with the use of only one them.
- MeSH
- chemometrika MeSH
- farmacie * MeSH
- léčivé přípravky * MeSH
- pomocné látky MeSH
- Ramanova spektroskopie MeSH
- tablety MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Nanofibrous scaffolds loaded with bioactive nanoparticles are promising materials for bone tissue engineering. METHODS: In this study, composite nanofibrous membranes containing a copolymer of L-lactide and glycolide (PLGA) and diamond nanoparticles were fabricated by an electrospinning technique. PLGA was dissolved in a mixture of methylene chloride and dimethyl formamide (2:3) at a concentration of 2.3 wt%, and nanodiamond (ND) powder was added at a concentration of 0.7 wt% (about 23 wt% in dry PLGA). RESULTS: In the composite scaffolds, the ND particles were either arranged like beads in the central part of the fibers or formed clusters protruding from the fibers. In the PLGA-ND membranes, the fibers were thicker (diameter 270 ± 9 nm) than in pure PLGA meshes (diameter 218 ± 4 nm), but the areas of pores among these fibers were smaller than in pure PLGA samples (0.46 ± 0.02 μm(2) versus 1.28 ± 0.09 μm(2) in pure PLGA samples). The PLGA-ND membranes showed higher mechanical resistance, as demonstrated by rupture tests of load and deflection of rupture probe at failure. Both types of membranes enabled the attachment, spreading, and subsequent proliferation of human osteoblast-like MG-63 cells to a similar extent, although these values were usually lower than on polystyrene dishes. Nevertheless, the cells on both types of membranes were polygonal or spindle-like in shape, and were distributed homogeneously on the samples. From days 1-7 after seeding, their number rose continuously, and at the end of the experiment, these cells were able to create a confluent layer. At the same time, the cell viability, evaluated by a LIVE/DEAD viability/cytotoxicity kit, ranged from 92% to 97% on both types of membranes. In addition, on PLGA-ND membranes, the cells formed well developed talin-containing focal adhesion plaques. As estimated by the determination of tumor necrosis factor-alpha levels in the culture medium and concentration of intercellular adhesion molecule-1, MG-63 cells, and RAW 264.7 macrophages on these membranes did not show considerable inflammatory activity. CONCLUSION: This study shows that nanofibrous PLGA membranes loaded with diamond nanoparticles have interesting potential for use in bone tissue engineering.
- MeSH
- buněčná adheze MeSH
- buněčné linie MeSH
- diamant chemie MeSH
- kostní náhrady chemie MeSH
- kyselina mléčná chemie MeSH
- kyselina polyglykolová chemie MeSH
- lidé MeSH
- mikrofilamenta metabolismus MeSH
- mikroskopie elektronová rastrovací MeSH
- myši MeSH
- nanočástice chemie ultrastruktura MeSH
- nanomedicína MeSH
- nanovlákna chemie ultrastruktura MeSH
- osteoblasty cytologie imunologie fyziologie MeSH
- proliferace buněk MeSH
- testování materiálů MeSH
- tkáňové inženýrství metody MeSH
- tkáňové podpůrné struktury chemie MeSH
- transmisní elektronová mikroskopie MeSH
- viabilita buněk MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Shrinkage of ceramic objects produced by Fused Depositon Ceramics 3D printing technology was studied as model procedure for production of biocompatible scaffolds. The formulation of ceramic composite filament tested was based on components such as aluminium and silicium oxides and thermoplastic polymer. The resulting ceramic material after sintering is approaching the chemical composition of the mullite ceramics, which has several interesting material properties. The shrinkage of the produced testing objects was studied as function of the particle content in starting composite and sintering temperature. Observed shrinkage of the ceramic bodies produced was on the level of 17% for 65 weight % and the 23% for 40 weight % of inorganic filler content at temperature 1200 °C, respectively, with well maintained shape. The tested ceramic scaffolds were produced using slice thickness of 0.50 mm and fill gap of 0.58 mm, with regular rectilinear infill pores generated by Slic3r.
The main goal of this study is to develop a micromechanical model of a particle-filled dental composite focused on the residual stress (RS) field developed during the curing process in its microstructure. A finite element model of a representative volume element of filler and resin was developed, and volumetric shrinkage was simulated during the curing process. Four material models (von Mises plasticity model, Drucker-Prager plasticity model, von Mises plasticity model with stress relaxation and Drucker-Prager plasticity with stress relaxation) of the polymer resin were built to assess the influence of the material model on the resulting internal stress. The relationship between the curing process and the magnitude of the stress components will be described, and an analysis of the post-curing state of the material in particular microstructure locations will be conducted in this study. Obtained RS is comparable to the stresses developed in the material under the external load. The substantial dependence on the choice of material model for resin is to be observed, and the suitability of particular models is discussed.
To evaluate the effectiveness of various means to combat the negative health effects of ultrafine particles emitted by internal combustion engines, a reliable, low-cost instrument for dynamic measurements of the exhaust emissions of ultrafine particulate matter (PM) is needed. In this study, an ordinary ionization-type building smoke detector was modified to serve as a measuring ionization chamber and utilized for dynamic measurements of PM emissions from diesel engines. When used with diluted exhaust, the readings show an excellent correlation with total particulate length. The instrument worked well with raw and diluted exhaust and with varying emission levels and is well suitable for on-board use.
