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
- Adult MeSH
- Metal Nanoparticles * MeSH
- Middle Aged MeSH
- Humans MeSH
- Microscopy, Electron, Scanning MeSH
- Nasal Mucosa pathology MeSH
- Pilot Projects MeSH
- Aged MeSH
- Sinusitis pathology MeSH
- Titanium isolation & purification metabolism MeSH
- Particle Size MeSH
- Iron isolation & purification metabolism MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Titanium MeSH
- Iron 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.
- Keywords
- Biodegradable composites, Indentation tests, Magnesium, Mechanical properties, PLA,
- MeSH
- Magnesium MeSH
- Elastic Modulus MeSH
- Polyesters analysis MeSH
- Polymers analysis MeSH
- Materials Testing * MeSH
- Hardness MeSH
- Viscosity MeSH
- Absorbable Implants * MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Magnesium MeSH
- poly(lactide) MeSH Browser
- Polyesters MeSH
- Polymers MeSH
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
- Biopsy methods MeSH
- Adult MeSH
- Palatine Tonsil pathology MeSH
- Humans MeSH
- Microscopy, Electron, Scanning MeSH
- Pilot Projects MeSH
- Amniotic Fluid cytology MeSH
- Reproducibility of Results MeSH
- Spectrometry, X-Ray Emission MeSH
- Tonsillitis diagnosis MeSH
- Particle Size * MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
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.
- MeSH
- Automobiles * MeSH
- Air Pollutants analysis chemistry MeSH
- Soot analysis chemistry MeSH
- Temperature MeSH
- Particle Size * MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Air Pollutants MeSH
- Soot MeSH
In the present work, hybrid composites were developed by using polyester waste fibers along with natural origin materials: olive root fibers and coir pitch filler. Such composite panels can be used as a potential alternative for fiber glass sunshade panels and room dividers in buildings. Hybrid composites were fabricated by mixing polyester waste fibers and olive root fibers in different ratios (0:100, 33:67, 67:33 and 100:0). Coir pith micro-particles with an average size of 312 d.nm were used as filler in the polyester matrix at three different levels (0%, 5%, and 10%) of the overall matrix weight. Mechanical properties, e.g., tensile strength, flexural strength and impact strength, thermal properties, e.g., coefficient of linear thermal expansion, thermo-gravimetric analysis (TGA) and environmental properties, e.g., water absorption, loss of density after exposure to weathering were characterized. For comparison purposes, a commercially available fiber glass sunshades sample was also investigated. Mixture design analysis was used to optimize the ratio of all components in the composite. Graphical comparison of experimental results using regression models showed a high degree of correlation. An optimized formulation of composite with an objective of maximization of tensile strength, flexural strength, impact strength and minimization of water absorption, density loss, as well as coefficient of linear thermal expansion, was determined at 70.83 wt%, 15.15 wt%, and 14.01 wt% of polyester waste fibers, olive root fibers and coir pith micro-fillers, respectively. Overall, it can be concluded that the developed hybrid composites from waste fibrous materials can be used as a promising alternative and a value-added application in buildings and construction purposes.
- Keywords
- building materials, coir pith filler, hybrid composite, mixture design analysis, olive root fiber, polyester waste fiber,
- Publication type
- Journal Article MeSH
This short communication presents a simple method of preparation of thin-metal nano-platelets utilizing metal sputtering and lift-off photolithography. The method offers complete control over size, shape and properties of nano-platelets of sub-micrometer thickness. Platelets with a thickness of 50⁻200 nm and with defined arbitrary shapes and sizes in the range of 15⁻300 μm were prepared from single or multiple metal layers by magnetron sputtering. Deposition of different metals in layers enabled fabrication of bi- or tri-metallic platelets with a magnetic core and differently composed surfaces. Highly reflective nano-platelets with a magnetic core allowed manipulation by magnetic fields, while different metallic surfaces served for functionalization by selected molecules. Submicron thin nano-platelets are extremely light (e.g., ~20 ng for a 100 μm × 100 μm × 0.1 μm gold nano-platelet) so that they can be attached to surfaces by only a few chemical bonds. At the same time their area is sufficiently large for simple optical recognition of their shape which is intended to label various characteristics depending on the specific surface functionalization of the given shape.
- Keywords
- lithography, magnetic particles, micro-particles,
- Publication type
- Journal Article MeSH
Although extensive research has shown the pathological effect of fine and ultrafine airborne particles, clear evidence of association of environmental exposure to them and inflammatory changes in human nasal mucosa is missing. Meanwhile, pathogenesis of chronic rhinosinusitis, despite being a disease with high prevalence in the population, is still unclear. The increasing evidence of the pro-inflammatory properties of these particles raises the question of their possible role in chronic rhinosinusitis. The presented study focused on detection of microsized anorganic particles and clusters of nanosized anorganic particles in the nasal mucosa of patients with chronic rhinosinusitis by Raman microspectroscopy and comparison of their composition to histologic findings. The results were compared to the findings in mucosa obtained from cadavers with no history of chronic rhinosinusitis. Solid particles were found in 90% of tissue samples in the group with chronic rhinosinusitis, showing histologic signs of inflammation in 95%, while in the control group, the particles were found in 20% of samples, with normal histologic findings in all of them. The main detected compounds were graphite, TiO2, amorphous carbon, calcite, ankerite and iron compounds. The results are in accordance with the premise that exogenous airborne particles interact with the nasal mucosa and possibly deposit in it in cases where the epithelial barrier is compromised in chronic rhinosinusitis.
- Keywords
- Raman microspectroscopy, airborne pollutants, chronic rhinosinusitis, fine and ultrafine particles, micro- and nanosized particles, nanotoxicology,
- MeSH
- Chronic Disease MeSH
- Humans MeSH
- Nasal Mucosa pathology MeSH
- Rhinitis * MeSH
- Sinusitis * MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article 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.
- Keywords
- Outdoor air pollution, aging, exposure, oxidative stress, particulate matter,
- MeSH
- Air Pollutants * analysis toxicity MeSH
- Humans MeSH
- MicroRNAs * MeSH
- Particulate Matter analysis MeSH
- Aging MeSH
- Air Pollution * adverse effects analysis MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
- Names of Substances
- Air Pollutants * MeSH
- MicroRNAs * MeSH
- Particulate Matter MeSH
Extremely simple procedures for the preparation of magnetic chitosan enzyme carriers have been developed and used for the immobilization of lipase and β-galactosidase as model enzymes. In the first case commercially available magnetite microparticles were entrapped in chitosan gel, while in the second case magnetic iron oxides microparticles were synthesized in chitosan matrix from ferrous sulfate using microwave irradiation. Immobilized enzymes showed long-term stability without leaching of enzyme from the support and enabled their repeated use without significant loss of activity.
- MeSH
- beta-Galactosidase chemistry MeSH
- Chitosan chemistry radiation effects MeSH
- Enzymes, Immobilized chemistry MeSH
- Lipase chemistry MeSH
- Microspheres * MeSH
- Microwaves MeSH
- Ferrosoferric Oxide chemistry radiation effects MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- beta-Galactosidase MeSH
- Chitosan MeSH
- Enzymes, Immobilized MeSH
- Lipase MeSH
- Ferrosoferric Oxide MeSH
A new type of promising chitosan beads with advanced properties were obtained under microwave radiation according to Green Chemistry principles. Biomaterials were prepared using chitosan as raw material and glutamic acid/1,5-pentanodiol mixture as crosslinking agents. Additionally beads were modified with Tilia platyphyllos extract to enhance their antioxidant properties. Beads were investigated over their chemical structure by FT-IR analysis. Also their morphology has been investigated by SEM method. Additionally swelling capacity of the obtained hydrogels was determined. Lack of cytotoxicity has been confirmed by MTT assay. Proliferation studies were carried out on L929 mouse fibroblasts. Advanced properties of the obtained beads were investigated by studying pH sensitivity and antioxidant properties by DPPH method. Also susceptibility to degradation and biodegradation by Sturm Test method was evaluated. Results shows that proposed chitosan beads and their eco-friendly synthesis method can be applied in cell therapy and tissue engineering.
- Keywords
- Advanced biomaterials, Beads, Cell culture, Chitosan, Microwave-assisted synthesis,
- MeSH
- Antioxidants pharmacology MeSH
- Biocompatible Materials pharmacology MeSH
- Cell Culture Techniques methods MeSH
- Chitosan chemistry MeSH
- Hydrogen-Ion Concentration MeSH
- Humans MeSH
- Microspheres * MeSH
- Microwaves * MeSH
- Mice MeSH
- Cell Proliferation drug effects MeSH
- Spectroscopy, Fourier Transform Infrared MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Antioxidants MeSH
- Biocompatible Materials MeSH
- Chitosan MeSH
