Experimental PVC Material Challenge in Subjects with Occupational PVC Exposure

BACKGROUND: Polyvinyl chloride (PVC) materials have been linked to asthma in several epidemiologic studies, but the possible causal factors remain unknown. PARTICIPANTS: We challenged 10 subjects experimentally to degraded PVC products under controlled conditions. All of the subjects had previously experienced respiratory symptoms suspected to be caused by this kind of exposure in their work place. Five subjects had doctor-diagnosed asthma. METHODS: The subjects were exposed to degraded PVC material in an exposure chamber; a challenge with ceramic tile was used as the control test. We followed exhaled nitric oxide, nasal NO, lung functions, cytokines [tumor necrosis factor-α (TNF-α), interleukin-4 (IL-4), IL-6, and IL-12] and NO in nasal lavage fluid (NAL) during and after the exposures. We also measured 2-ethylhexanol in exhaled breath samples and NAL. RESULTS: On the morning after the PVC exposure, subjects reported respiratory tract symptoms significantly more often than they did after the control test (50% vs. 0%, respectively; p = 0.029; n = 10). We did not detect any changes in lung functions or levels of exhaled NO, nasal NO, or NO in NAL after PVC challenge compared with the control test. Cytokine levels increased after both exposures, with no statistically significant difference between situations. All of the exhaled breath samples collected during the PVC exposure contained 2-ethylhexanol. CONCLUSIONS: PVC flooring challenge can evoke respiratory tract symptoms in exposed subjects. Our results do not support the hypothesis that PVC materials themselves evoke immediate asthmatic reactions. The chamber test used is well suited to this type of exposure study

Porphyrins closed in sol-gel matrix

The need for new, chemically and physically stable luminescent materials operating with UV excitations has stimulated research on luminescence properties of doped sol–gel material. In this work, it has been presented a technology of production of silica gels doped with organic molecules, lanthanide compounds and organic/inorganic composites. Optical properties of these materials as functions of temperature, concentration and excitation wavelength are presented. Dynamics of excited states has been discussed based on the decay times and emission efficiencies data. Mechanisms of ligand-to-metal energy transfer as well as other processes affecting emission efficiency are considered. Silica sol–gels doped with di-aminoacid derivatives of porphyrins: PP(Ser)2(Arg)2, PP(Ala)2(Arg)2, PP(Met)2(Arg)2, where Met, Arg and Ser denote methionine, serine and arginine aminoacids, respectively, and H2TTMePP {tetrakis[4-(trimethylammonio)phenyl]-21H,23H-porphine} have been obtained and spectroscopically studied. These materials can find applications as phosphors or sensors of UV irradiation

Investigations of hydroxyapatite nanocomposites against anaerobic bacteria

Nanocrystalline apatites Ca10(PO4)6(OH)2 (HAp) non-doped and doped with Ag+ and Eu3+ ions were synthesized by different wet chemistry methods. The obtained hydroxyapatite was loaded with Ag0, as well as nitroimidazole antimicrobials: metronidazole and tinidazole. The antimicrobial activity of the obtained materials against Prevotella bivia and Parabacteroides distasonis was studied. The method used for the antibacterial susceptibility testing was broth microdilution, according to the CLSI – Clinical and Laboratory Standard Institute – standard M11-A8; agar Schaedler, enriched with 50% LHB - Lysed Horse Blood, was used as a medium for culturing strains. The antibacterial activity increased for the immobilized antibiotics – HAp doped with metronidazole and tinidazole was six times more bactericidal than non-immobilised metronidazole for both clinical isolates. In comparison with non-immobilised tinidazole, HAp immobilised with tinidazole was six thousand times more effective against P. distasonis and two hundred times more effective against P. bivia. HAp doped with tetracycline was over two times more bactericidal than tetracycline non-immobilised (according to the literature data). The exact MIC for bionanocomposites of HAp and silver was not obtained. The research shows that bionanocomposites of hydroxyapatite are good drug carriers for both antibiotics and silver particles and ions. The use of bionanocomposites of apatite immobilised with antibiotics in dentistry could result in a prolonged antibacterial activity of these compounds

The f-f Emission of Pr3+ Ion as an Optical Probe for the Structural Properties of YAG Nanoceramics

Transparent Pr-doped YAG nanocerainics composed of grains with an average size of 42 nm, were fabricated with the Low Temperature Hight Pressure (LTHP) sintering technique using the corresponding nanopowders as the starting materials. The structure of the nanoceramics was analyed by X-ray diffraction (XRD). The effect of the sintering conditions on the structural properties is discussed on the basis of the changes of the spectroscopic properties of Pr3+. In particular, the intensities and decays of the emission transitions originating from the P-3(0) and D-1(2) levels are investigated and correlated with structural properties of the material, such as microstrains produced by the high-pressure process

Structural and spectroscopic features of Ca9M(PO4)7 (M\ua0=\ua0Al3+, Lu3+) whitlockites doped with Pr3+ ions

In this work we present the structural and spectroscopic properties of Ca9M(PO4)7 (M = Al, Lu) whitlockite compounds doped with Pr3+ ions. The Al containing samples were prepared by the citrate route, while the Lu based samples were prepared by standard solid state reaction. The structural properties were investigated by XRD measurements and Rietveld analysis. Detailed spectroscopic properties like emission and excitation spectra, luminescence kinetics and luminescence temperature quenching were measured to determine the influence of different trivalent host metal on the Pr3+ ions. Pr3+ enter in the three Ca2+ sites in the Ca9Al(PO4)7 compounds, creating some defect to compensate the charge mismatch, whereas in the Ca9Lu(PO4)7 Pr3+ ions occupy four Ca2+/Lu3+ sites, where no charge compensation is needed. The emission spectra are similar for both materials. Efficient quenching of the 1D2 emission was observed, while the 3P0 emission remains stable for all dopant concentrations. Decay times were found to be non-single exponential due to the occupation of different sites by the Pr3+ ions. The luminescence temperature quenching measurements have revealed that two different mechanisms (multi-phonon relaxation and cross-relaxation processes) are responsible for the emission quenchin

Multifunctional lanthanide and silver ions co-doped nano-chlorapatites with combined spectroscopic and antimicrobial properties.

International audienceNanocrystalline chlorapatites (Ca10(PO4)6Cl2) doped with lanthanide ions (Eu3+, Er3+ and Yb3+) and co-doped with silver ions (Ag+) were synthesized by a hydrothermal synthesis route. XRD, TEM, and SAED measurements indicated that the powders are single phased and crystallize with a hexagonal structure with good dispersion. The results showed well crystallized chlorapatite grains with a diameter of about 45 nm. The antimicrobial activity of the nanoparticles against Escherichia coli ATCC 11229 and ATCC 25922, Klebsiella pneumoniae ATCC 700603, and Pseudomonas aeruginosa PAO1 and ATCC 27853 was studied. The best activity was observed for the Eu3+,Ag+:Ca10(PO4)6Cl2 and Eu3+,Ag+,Yb3+:Ca10(PO4)6Cl2 compositions. These multifunctional nanocrystalline powders could be used as a promising antimicrobial agent and material for bio-detection

Iron oxides nanoparticles (IOs) exposed to magnetic field promote expression of osteogenic markers in osteoblasts through integrin alpha-3 (INTa-3) activation, inhibits osteoclasts activity and exerts anti-inflammatory action

International audienceBackgroundPrevalence of osteoporosis is rapidly growing and so searching for novel therapeutics. Yet, there is no drug on the market available to modulate osteoclasts and osteoblasts activity simultaneously. Thus in presented research we decided to fabricate nanocomposite able to: (i) enhance osteogenic differentiation of osteoblast, (i) reduce osteoclasts activity and (iii) reduce pro-inflammatory microenvironment. As a consequence we expect that fabricated material will be able to inhibit bone loss during osteoporosis.ResultsThe α-Fe2O3/γ-Fe2O3 nanocomposite (IOs) was prepared using the modified sol–gel method. The structural properties, size, morphology and Zeta-potential of the particles were studied by means of XRPD (X-ray powder diffraction), SEM (Scanning Electron Microscopy), PALS and DLS techniques. The identification of both phases was checked by the use of Raman spectroscopy and Mössbauer measurement. Moreover, the magnetic properties of the obtained IOs nanoparticles were determined. Then biological properties of material were investigated with osteoblast (MC3T3), osteoclasts (4B12) and macrophages (RAW 264.7) in the presence or absence of magnetic field, using confocal microscope, RT-qPCR, western blot and cell analyser. Here we have found that fabricated IOs: (i) do not elicit immune response; (ii) reduce inflammation; (iii) enhance osteogenic differentiation of osteoblasts; (iv) modulates integrin expression and (v) triggers apoptosis of osteoclasts.ConclusionFabricated by our group α-Fe2O3/γ-Fe2O3 nanocomposite may become an justified and effective therapeutic intervention during osteoporosis treatment