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排序方式: 共有332条查询结果,搜索用时 15 毫秒
311.
Review of current literature on pathogenesis and diagnostic approach to interstitial lung disease (ILD) in systemic sclerosis (SSc) was presented. The review focused in particular on the bronchoalveolar lavage (BAL). The experimental study was aimed to established whether early performed BAL is corresponding with clinical data, especially within a group with signs and symptoms of overt ILD. BAL was performed in 25 non-smoking subjects (22 women, 3 men) with SSc (according to ARA) with no systemic steroids. Diagnosis of lung involvement (presented in 18 patients) was based on history and physical examination, chest X-ray, lung function tests and arterial blood gas determination. BAL was routinely stained and assessed. Changes in BAL cytological examination were observed in all patients. An increased total cell number as well as increased percentage of neutrophils and eosinophils was noted. A lymphocyte number rise was not statistically significant. A lung involvement in group with ILD was more advanced than in group without ILD and controls, i.e. neutrophilic alveolitis in half cases (9/18 vs. 0/7 in group with no ILD) and oesinophilic alveolitis in 33% cases (6/18 vs. 2/7). Lymphocytic alveolitis was found in one patient with ILD and in two patients without ILD. The value of BAL in a diagnostic approach to the ILD in SSc was emphasized. Sensitivity of BAL in case of early ILD seems to be comparable with sensitivity of lung function tests (e.g. DLCO) and computerized tomography. The answer to the question which of the above mentioned methods in most appropriate to detect ILD risk in SSc remains unknown. 相似文献
312.
Marta W. Chrszcz Izabela M. Barszczewska-Rybarek Alicja Kazek-Ksik 《International journal of molecular sciences》2022,23(9)
The growing scale of secondary caries and occurrence of antibiotic-resistant bacterial strains require the development of antibacterial dental composites. It can be achieved by the chemical introduction of quaternary ammonium dimethacrylates into dental composites. In this study, physicochemical and antibacterial properties of six novel copolymers consisting of 60 wt. % quaternary ammonium urethane-dimethacrylate analogues (QAUDMA) and 40 wt. % triethylene glycol dimethacrylate (TEGDMA) were investigated. Uncured compositions had suitable refractive index (RI), density (dm), and glass transition temperature (Tgm). Copolymers had low polymerization shrinkage (S), high degree of conversion (DC) and high glass transition temperature (Tgp). They also showed high antibacterial effectiveness against S. aureus and E. coli bacterial strains. It was manifested by the reduction in cell proliferation, decrease in the number of bacteria adhered on their surfaces, and presence of growth inhibition zones. It can be concluded that the copolymerization of bioactive QAUDMAs with TEGDMA provided copolymers with high antibacterial activity and rewarding physicochemical properties. 相似文献
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314.
Konrad Walkowiak Sandra Paszkiewicz Izabela Irska Agnieszka Kochmanska Kamil Dydek Anna Boczkowska Rafal Stanik Mike Gude Amelia Linares Tiberio Ezquerra 《Advanced Engineering Materials》2023,25(13):2300046
Bionanocomposites based on poly(trimethylene 2,5-furandicarboxylate)-block-poly(tetramethylene oxide) (PTF-b-F-PTMO) with various contents of carbon nanofibers, graphene nanoplatelets and a hybrid system of these nanoparticles are synthesized via in situ polymerization. The dispersion of nanoparticles in the nanocomposites is determined using a scanning electron microscope and optical microscopy images. The thermal properties are studied employing differential scanning calorimetry, dynamic mechanical thermal analysis, and thermogravimetric analysis. The melt viscosity of the synthesized materials is determined using rheological measurements. Mechanical properties, along with the thermal and electrical conductivity, are also analyzed. The synthesized polymer nanocomposites are processed using injection molding and they display mechanical properties of elastomers during mechanical testing, which indicates that the obtained materials are, in fact, thermoplastic elastomers (TPE). Compared to a neat matrix (PTF-b-F-PTMO 50/50), the incorporation of nanoparticles causes an increase in the value of the degree of crystallinity and the value of the tensile modulus values (E) of the nanocomposites. Such reinforced bionanocomposites are especially interesting from an applicative point of view. They can be used as components of fuel systems, bumpers, or cupholders. 相似文献
315.
Robert Pietrzak Piotr Nowicki Justyna Kaźmierczak Izabela Kuszyńska Joanna Goscianska Jacek Przepiórski 《Chemical Engineering Research and Design》2014
A method for obtaining activated carbons from cherry stones by chemical activation with NaOH is described. Carbonaceous adsorbents were obtained by two methods of activation (physical mixing and impregnation) and two variants of thermal treatment (at a constant or increasing temperature). Cherry stones were proved to be effective cheap precursors of carbon adsorbents, characterised by large pore volume (ranging from 0.22 to 0.47 cm3/g) and good sorption abilities (iodine number from 343 to 996 mg/g). The activated carbons obtained usually have strongly microporous structure and acidic surface character. The best physicochemical properties and adsorption properties towards iodine were found to be shown by the carbon samples obtained by physical mixing of the precursor or char with the activating agent followed by activation at 600 °C. 相似文献
316.
Janusz Kozakiewicz Izabela OfatIzabela Legocka Joanna Trzaskowska 《Progress in Organic Coatings》2014
Aqueous silicone-acrylic dispersions with core–shell particle structure can be obtained in the process of emulsion polymerization of acrylic or methacrylic monomers in previously synthesized silicone resin dispersions. If the glass transition temperature (Tg) of the shell is around +120 °C or higher, drying of such dispersions leads to “nanopowders” which can be applied as impact modifiers for powder coatings and plastics due to the presence of low Tg silicone resin contained in the hybrid nanoparticles. The aim of our study was to investigate the effect of silicone resin composition on the properties of dispersions and the corresponding nanopowders what, in turn, was expected to influence the properties of powder coatings modified with such nanopowders. Silicone resin dispersions (DSI) were synthesized by emulsion polymerization of three silicone monomers: octamethylcyclotetrasiloxane (D4), methyltrimethoxysilane (METMS) and methacryloyltrimethoxysilane (MATMS) in the presence of dodecylbenzenesulphonic acid playing the role of both surfactant and polymerization catalyst. Silicone-acrylic hybrid dispersions (DASI) having core–shell particle structure confirmed by TEM were further obtained by emulsion polymerization of methyl methacrylate in DSI, and eventually nanopowders (NP-DASI) were produced by spray-drying of DASI. A designed experiment was conducted where the different proportions of D4, METMS and MATMS were used in DSI synthesis and a range of properties of DSI, DASI and NP-DASI were tested. A significant effect of starting silicone monomers composition (reflected in silicone resin structure) on dispersion particle size was observed what could be explained by differences in their hydrophobicity. SEM investigations revealed that NP-DASI were produced in the form of 1–10 μm agglomerates of round-shaped nanoparticles of ca. 120 nm in size. Two clear glass transition temperatures (Tg) of NP-DASI were identified by DSC: one attributed to silicone part – around −120 °C – and the other attributed to poly(methyl methacrylate) (PMM) part – around +120 °C. Tg attributed to silicone part decreased with increased share of D4 and MATMS in the silicone monomers composition while Tg of PMM part showed a minimum for specific composition of silicone monomers. 相似文献
317.
318.
Giannona S Firkowska I Rojas-Chapana J Giersig M 《Journal of nanoscience and nanotechnology》2007,7(4-5):1679-1683
In this study, we describe the spatial organization of CAL-72 osteoblast-like cells on arrays of vertically aligned multi-walled carbon nanotubes (VACNTs). It was observed that, unlike cell growth on non-patterned surfaces, the cell attachment and spreading process on VACNTs was significantly enhanced. Additionally, since carbon nanotubes are known to possess resilient mechanical properties and are chemically stable, the effect of periodic arrays of VACNTs on CAL-72 osteoblast-like cells was also studied. The periodicity and alignment of VACNTs considerably influenced growth, shape and orientation of the cells by steering toward the nanopattern. This situation is of great interest for the potential application of VACNTs in bone bioenginnering. This data provides evidence that CAL-72 osteoblast-like cells can sense physical features at the nanoscale. These results give a fascinating insight into the ways in which cell growth can be influenced by man-made nanostructures and could provide a framework for achieving controlled cell guidance with controlled organization and special physical properties. 相似文献
319.
320.
Tomasz Olszowski Irena Baranowska-Bosiacka Izabela Gutowska Katarzyna Piotrowska Katarzyna Mierzejewska Jan Korbecki Mateusz Kurzawski Maciej Tarnowski Dariusz Chlubek 《International journal of molecular sciences》2015,16(9):21410-21427
Cadmium at environmental concentrations is a risk factor for many diseases, including cardiovascular and neurodegenerative diseases, in which macrophages play an important role. The aim of this study was to evaluate the effects of cadmium at low environmental (nanomolar) concentrations on apoptotic processes in THP-1(acute monocytic leukemia cells line)-derived macrophages, with special focus on mitochondrial events involved. Macrophages were incubated with various cadmium chloride (CdCl2) solutions for 48 h at final concentrations of 5 nM, 20 nM, 200 nM and 2 µM CdCl2. Cell viability was measured using flow cytometry. Flow cytometric measurement (annexin V/FITC (annexin V/fluorescein isothiocyanate) and PI (propidium iodide) double staining) was used to quantify the extent of apoptosis. Fluorescence and confocal microscopy were used for imaging of apoptosis process. Changes in mitochondrial membrane potential were monitored using cytofluorimetry after cell staining with JC-1(5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazol-carbocyane iodide) probe. Mitochondrial ROS (reactive oxygen species) levels were measured cytofluorimetrically after incubation of cells with mitochondrial superoxide indicator (MitoSOX) red fluorescent marker. The mRNA expression of Bcl-2 and Bax was analysed with qRT-PCR. Our study demonstrates that cadmium, even at low environmental concentrations, exerts mitochondrial toxicity in THP-1 macrophages. Forty-eight-hour exposure to very low concentrations reduces cell viability and results in cell death by apoptosis and necrosis. The decrease in mitochondrial membrane potential, increased ROS production, increased Bax and decreased Bcl-2 mRNA expression are mitochondrial events involved in cadmium-induced apoptosis. 相似文献