micro-particle
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We evaluated the degradation of cortical bone tissue by hydrochloric acid (HCl) since intentional bone decalcification in a forensic context has not been studied on a histomorphological level. We used 70 pig metatarsal bones split into subsamples and immersed in one of three concentrations of acidic solutions (0.5M, 1M, 2M HCl) for two and four hours. We analyzed the cortical thicknesses on transversal cross-sections, thicknesses of the three histomorphologically distinct zones present in acid-immersed bones, and number and area of crystals present in one of the zones. Furthermore, we analyzed the ratio of calcium to phosphorus (Ca:P). We observed a division of the cortical bone cross section into three distinctive zones: demineralized matrix (DM) in the periosteal part of bone, middle contact zone (CZ), and mineralized matrix (MM) in the endosteal part of bone. With increasing acid concentration and time of immersion (from 0.5M HCl for 2h to 2M HCl for 4h), the thickness of DM increased by 67%, the thickness of CZ increased by 56%, and the thickness of MM decreased by 32%. The Ca:P ratio in the contact zone of acid-treated samples did not change significantly with changing acid concentration and time of immersion. The Ca:P ratio of the CZ decreased by 10% when compared to the Ca:P ratio of MM in acid-treated samples. Moreover, we observed crystals on the outer periosteal border of the DM zone, in the CZ, and in the MM Haversian/Volkmann's canals. The size and number of the crystals in the CZ of acid-treated bones increased with acid concentration and time of acid immersion. Moreover, we also observed significant differences in all analyzed properties between anatomical regions. Due to varying reactions to acid immersion among anatomical regions, bone micro-degradation should be observed separately for each region.
- MeSH
- fosfor metabolismus MeSH
- kortikální kost diagnostické zobrazování metabolismus ultrastruktura MeSH
- kyselina chlorovodíková toxicita MeSH
- metatarzální kosti diagnostické zobrazování metabolismus ultrastruktura MeSH
- mikroskopie elektronová rastrovací MeSH
- okostice diagnostické zobrazování ultrastruktura MeSH
- rentgenová mikrotomografie MeSH
- soudní patologie MeSH
- spektrometrie rentgenová emisní MeSH
- Sus scrofa MeSH
- vápník metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Príspevok sa venuje analýze rôznych frakcií aerosólu vrátane nanometrických, mikrometrických častíc a PM "particulate matter" častíc v pracovnom ovzduší. Z výsledkov vyplýva, že analýzou veľkostnej distribúcie častíc pri výrobe oceľových rúr valcovaním za tepla, konkrétne pri dierovacom lise, sa preukázala prítomnosť PM častíc s rozmermi menšími ako 0,5 μm (7,1 μg/m3), ako 1 μm (16,4 μg/m3), ako 2,5 μm (40,4 μg/m3), ako 4,0 μm (58,6 μg/m3) a ako 10 μm (95,1 μg/m3). Ďalej sme výsledky vyhodnocovali ako veľkostnú distribúciu častíc podľa ich početnosti. Z celkového počtu častíc v odobratom objeme vzduchu 4,90⋅105 bolo 4,13⋅105 nanočastíc (84,4 %). Na druhom pracovisku – pri tŕňovej tyči – sme analyzovali podobne PM častice. Výsledky preukázali prítomnosť PM0,5 (2,8 μg/m3), PM1,0 (3,9 μg/m3), PM2,5 (15,5 μg/m3) a PM10 (119,9 μg/m3). V odobratom objeme vzduchu bolo z celkového počtu 5,75⋅105 častíc 5,29⋅105 nanočastíc (92,1 %). Z nameraných hodnôt vyplýva, že je dôležité objektivizovať častice v pracovnom ovzduší aj v nanorozmeroch a mikrorozmeroch, pretože môžu predstavovať potenciálne riziko poškodenia zdravia.
The article deals with the analysis of various aerosol fractions, including nanometric, micrometric particles and particulate matter (PM), in the working atmosphere. Analysis of particle distribution in the production of steel tubes by hot rolling, precisely at the punching press has been shown the presence of PM particles with diameter less than 0.5 μm (7.1 μg/m3), 1 μm (16.4 μg/m3), 2.5 μm (40.4 μg/m3), less than 4.0 μm (58.6 μg/m3) and less than 10 μm (95.1 μg/m3). We further evaluated the results of particle size distribution according to their quantity. We have analysed of the total number of particles in the withdrawn air volume of 4.90⋅105. The results showed that 84.4% (4.13⋅105) of the total number of particles is in the range of nanometres. In the another workplace with the thorn rods production, the results showed the presence of PM0.5 (2.8 μg/m3), PM1.0 (3.9 μg/m3), PM2.5 (15.5 μg/m3) and PM10 (119.9 μg/m3). The total number of particles in the nanometre range was 5.29⋅105 (92.1%). The total number of particles of this analysis of the air was 5.75⋅105. From the measured values, it is important to objectify the particles in the working atmosphere even in nano and micro dimensions, as they may pose a potential risk of damage to health.
OBJECTIVE: The aim of this prospective study is to evaluate presence and quantity of micro- and nanosized particles (NPs) and interindividual differences in their distribution and composition in nasal mucosa. METHODS: Six samples of nasal mucosa obtained by mucotomy from patients with chronic hypertrophic rhinosinusitis were examined. Samples divided into 4 parts according to the distance from the nostrils were analyzed by scanning electron microscopy and Raman microspectroscopy to detect solid particles and characterize their morphology and composition. A novel method of quantification of the particles was designed and used to evaluate interindividual differences in distribution of the particles. The findings were compared with patients' employment history. RESULTS: In all the samples, NPs of different elemental composition were found (iron, barium, copper, titanium, etc.), predominantly in the parts most distant from nostrils, in various depths from the surface of the mucosa and interindividual differences in their quantity and composition were found, possibly in relation to professional exposition. CONCLUSIONS: This study has proven the possibility of quantification of distribution of micro- and nanosized particles in tissue samples and that the NPs may deposit in deeper layers of mucosa and their elemental composition may be related to professional exposition to the sources of NPs.
- MeSH
- dospělí MeSH
- kovové nanočástice * MeSH
- lidé středního věku MeSH
- lidé MeSH
- mikroskopie elektronová rastrovací MeSH
- nosní sliznice patologie MeSH
- pilotní projekty MeSH
- senioři MeSH
- sinusitida patologie MeSH
- titan izolace a purifikace metabolismus MeSH
- velikost částic MeSH
- železo izolace a purifikace metabolismus MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Assessment of the impact that air contaminants have on health is difficult as this is a complex mixture of substances that varies depending on the time and place. There are many studies on the association between air pollution and increased morbidity and mortality. Before the effect of polluted air is manifested at the level of the organs, an impact can be observed at the molecular level. These include some new biomarkers, like a shortening of the mean telomere length in DNA, dysregulation of gene expression caused by microRNA levels or a variation in the copy number of mitochondrial DNA. These changes may predispose individuals to premature development of age-related diseases and consequently to shortening of life. The common attribute, shared by changes at the molecular level and the development of diseases, is the presence of oxidative stress.
- MeSH
- látky znečišťující vzduch * analýza toxicita MeSH
- lidé MeSH
- mikro RNA * MeSH
- pevné částice analýza MeSH
- stárnutí MeSH
- znečištění ovzduší * škodlivé účinky analýza MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
This work deals with the mechanical characterization by depth-sensing indentation (DSI) of PLLA and PLDA composites reinforced with micro-particles of Mg (up to 15wt%), which is a challenging task since the indented volume must provide information of the bulk composite, i.e. contain enough reinforcement particles. The composites were fabricated by combining hot extrusion and compression moulding. Physico-chemical characterization by TGA and DSC indicates that Mg anticipates the thermal degradation of the polymers but does not compromise their stability during processing. Especial emphasis is devoted to determine the effect of strain rate and Mg content on mechanical behavior, thus important information about the visco-elastic behavior and time-dependent response of the composites is obtained. Relevant for the intended application is that Mg addition increases the elastic modulus and hardness of the polymeric matrices and induces a higher resistance to flow. The elastic modulus obtained by DSI experiments shows good agreement with that obtained by uniaxial compression tests. The results indicate that DSI experiments are a reliable method to calculate the modulus of polymeric composites reinforced with micro-particles. Taking into consideration the mechanical properties results, PLA/Mg composite could be used as substitute for biodegradable monolithic polymeric implants already in the market for orthopedics (freeform meshes, mini plates, screws, pins, …), craniomaxillofacial, or spine.
BACKGROUND: Nanotechnology is receiving enormous funding. Very little however is known about the health dangers of this technology so far. Chronic tonsillitis is one of a number of diseases called idiopathic. Among other factors, the tonsils are exposed to suspended particles in inhaled air including nano particles. The objective of this study was to detect and evaluate metallic particles in human tonsil tissue diagnosed with chronic tonsillitis and in amniotic fluid as a comparison. METHODS: . Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) was used for identification of solid particles in a total of 64 samples of routinely analyzed biopsy and cytologic material. RESULTS: Almost all samples were found to contain solid particles of various metals. The most frequent, regardless of diagnosis, were iron, chromium, nickel and aluminium. The size, determined using SEM, varied from around 500 nm to 25 µm. The majority formed aggregates of several micrometers in size but there were a significant number of smaller (sub-micrometer or nano-sized) particles present. The incidence of metallic particles was similar in child and adult tissues. The difference was in composition: the presence of several metals in adults was due to occupational exposure. CONCLUSIONS: The presence of metallic particles in pathologically altered tissues may signal an alternative causation of some diseases. The ethiopathogenic explanation of these diseases associated with the presence of nano-sized particles in the organism has emerged into a new field of pathology, nanopathology.
- MeSH
- biopsie metody MeSH
- dospělí MeSH
- krční mandle patologie MeSH
- lidé MeSH
- mikroskopie elektronová rastrovací MeSH
- pilotní projekty MeSH
- plodová voda cytologie MeSH
- reprodukovatelnost výsledků MeSH
- spektrometrie rentgenová emisní MeSH
- tonzilitida diagnóza MeSH
- velikost částic * MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The effect of process scale-up from 4 to 400-L high-shear granulator on the release kinetics of the active ingredient from pharmaceutical granules has been investigated. The dissolution and disintegration rates of the granules were measured simultaneously by the combination of UV/vis spectroscopy and static light scattering. The granule batches were found to consist of sub-populations with qualitatively different dissolution behavior: "weaker" granules that disintegrated during dissolution, and "stronger" granules that retained their size and from which the active ingredient was gradually leached. The existence of these sub-populations was attributed to non-uniform distribution of normal and shear forces that prevail in granulators of different size. This hypothesis was confirmed by preparing granules at increasing values of the Froude number at the 4-L scale, and observing a transition from the break-up dissolution mode to the leaching dissolution mode with increasing granule densification. The simultaneous observation of solute concentration and particle size distribution during granules dissolution proved to be a useful tool for the understanding of dissolution mechanisms and for identifying non-uniformities of process conditions that can occur during scale-up.
The paper addresses the wear particles released from commercially available "low-metallic" automotive brake pads subjected to brake dynamometer tests. Particle size distribution was measured in situ and the generated particles were collected. The collected fractions and the original bulk material were analyzed using several chemical and microscopic techniques. The experiments demonstrated that airborne wear particles with sizes between 10 nm and 20 μm were released into the air. The numbers of nanoparticles (< 100 nm) were by three orders of magnitude larger when compared to the microparticles. A significant release of nanoparticles was measured when the average temperature of the rotor reached 300°C, the combustion initiation temperature of organics present in brakes. In contrast to particle size distribution data, the microscopic analysis revealed the presence of nanoparticles, mostly in the form of agglomerates, in all captured fractions. The majority of elements present in the bulk material were also detected in the ultra-fine fraction of the wear particles.
Recent advances in the fabrication, characterization and application of micro- and nano-particles that possess a non-uniform internal structure are reviewed. The particle structures include core-shell particles, particles with multiple cores or a multi-layered structure, porous particles with both regular and random pore structure, as well as complex composite particles possessing several of the above features. Particles based on "hard" inorganic materials such as silica, "soft" organic materials such as polymers and their composites are considered. The fabrication approaches include bottom-up self-assembly techniques, templating methods, microfluidics, and various emulsion-based routes to structured micro- and nano-particle formation, combined with both physical (e.g. Pickering emulsions) and chemical (e.g. polymerization, precipitation) processes for the material deposition. The applications of the structured particles for the encapsulation and controlled delivery of active substances are then reviewed with emphasis on those systems where the complex particle structure can provide specific benefits such as in-situ formation of the active substance or precise control over the release profile. Likely future research directions and prospects are discussed.
- MeSH
- léčivé přípravky aplikace a dávkování chemie MeSH
- lékové transportní systémy * MeSH
- lidé MeSH
- mikrosféry MeSH
- nanočástice MeSH
- oxid křemičitý chemie MeSH
- polymery chemie MeSH
- poréznost MeSH
- příprava léků metody MeSH
- racionální návrh léčiv MeSH
- velikost částic MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
