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141.
Gustavsson J Altankov G Errachid A Samitier J Planell JA Engel E 《Journal of materials science. Materials in medicine》2008,19(4):1839-1850
Thin films of silicon nitride (Si3N4) can be used in several kinds of micro-sized biosensors as a material to monitor fine environmental changes related to the
process of bone formation in vitro. We found however that Si3N4 does not provide optimal conditions for osseointegration as osteoblast-like MG-63 cells tend to detach from the surface when
cultured over confluence. Therefore Si3N4 was modified with self-assembled monolayers bearing functional end groups of primary amine (NH2) and carboxyl (COOH) respectively. Both these modifications enhanced the interaction with confluent cell layers and thus
improve osseointegration over Si3N4. Furthermore it was observed that the NH2 functionality increased the adsorption of fibronectin (FN), promoted cell proliferation, but delayed the differentiation.
We also studied the fate of pre-adsorbed and secreted FN from cells to learn more about the impact of above functionalities
for the development of provisional extracellular matrix on materials interface. Taken together our data supports that Si3N4 has low tissue integration but good cellular biocompatibility and thus is appropriate in cellular biosensor applications
such as the ion-sensitive field effect transistor (ISFET). COOH and NH2 chemistries generally improve the interfacial tissue interaction with the sensor and they are therefore suitable substrates
for monitoring cellular growth or matrix deposition using electrical impedance spectroscopy. 相似文献
142.
Bodenmann Guy; Plancherel Bernard; Beach Steven R. H.; Widmer Kathrin; Gabriel Barbara; Meuwly Nathalie; Charvoz Linda; Hautzinger Martin; Schramm Elisabeth 《Canadian Metallurgical Quarterly》2008,76(6):944
The aim of this study was to evaluate the effectiveness of treating depression with coping-oriented couples therapy (COCT) as compared with cognitive-behavioral therapy (CBT; A. T. Beck, C. Ward, & M. Mendelson, 1961) and interpersonal psychotherapy (IPT; M. M. Weissman, J. C. Markowitz, & G. L. Klerman, 2000). Sixty couples, including 1 clinically depressed partner, completed pre- and posttest questionnaires as well as follow-up assessments at 6-month intervals over the subsequent 1.5 years. Effects of the 3 treatments on depressive symptomatology assessed by the Beck Depression Inventory (A. T. Beck, A. J. Rush, B. L. Shaw, & G. Emery, 1979) and Hamilton Rating Scale for Depression (M. Hamilton, 1960); recovery rates; and relapse rates were examined. Additionally, changes in relationship quality were evaluated. Results suggest that the COCT is as effective in improving depressive symptomatology as are the well-established, evidenced-based CBT and IPT approaches. The COCT did not demonstrate a significantly better outcome with regard to self-reported relationship satisfaction or dyadic coping; however, it did produce significant improvements in partners' expressed emotion, changes that were not seen in other treatment conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
143.
Barbara Elisabeth Ascher 《The Journal of Architecture》2016,21(3):433-458
The late 1970s and early 1980s witnessed one of the most influential shifts within the organisational system of production for Norwegian mass housing. Although the increased availability of resources following the Second World War and the discovery of North Sea oil put the Norwegian government in a favourable position for investing in state-sponsored housing programmes, such investments did not happen. Instead, the strong public responsibility for affordable housing as a right of all citizens was weakened, and housing evolved into a commodity to be traded primarily on the free market.
Hallagerbakken, a housing project within the Holmlia satellite town—the last large housing development in the south of Oslo—has been influenced by several of the changes that occurred in the housing sector during this period. The resulting hybrid housing typology represented an innovation in the Norwegian setting, and, as a result, the project provides a starting point for re-evaluating some of the shifts towards a more market-oriented reality within architecture and the built environment. 相似文献
144.
Analysis of protein and peptide mixtures via capillary electrophoresis is hindered by nonspecific adsorption of analytes to the capillary walls, resulting in poor separations and quantitative reproducibility. Phospholipid bilayer (PLB) coatings are very promising for improving protein and peptide separations due to the native resistance to nonspecific protein adsorption offered by PLBs; however, these coatings display limited chemical and temporal stability. Here, we show the preparation and characterization of a highly cross-linked, polymerized phospholipid capillary coating prepared using bis-SorbPC. Poly(bis-SorbPC) PLB coatings are prepared in situ within fully enclosed fused silica capillaries via self-assembly and radical polymerization. Polymerization of the PLB coating stabilizes the membrane against desorption from the surface and migration in an electric field, improves the temporal and chemical stability, and allows for the separation of both cationic and anionic proteins, while preserving the native resistance to nonspecific protein adsorption of natural PLBs. 相似文献
145.
Supercritical antisolvent versus coevaporation: preparation and characterization of solid dispersions 总被引:1,自引:0,他引:1
Majerik V Horváth G Szokonya L Charbit G Badens E Bosc N Teillaud E 《Drug development and industrial pharmacy》2007,33(9):975-983
The objective of this work was to improve the dissolution rate and aqueous solubility of oxeglitazar. Solid dispersions of oxeglitazar in PVP K17 (polyvinilpyrrolidone) and poloxamer 407 (polyoxyethylene-polyoxypropylene block copolymer) were prepared by supercritical antisolvent (SAS) and coevaporation (CoE) methods. Drug-carrier formulations were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, gas chromatography, UV/VIS spectroscopy and in vitro dissolution tests. The highest dissolution rate (nearly 3-fold higher than raw drug) was achieved by preparation of drug/PVP K17 coevaporate. Oxeglitazar/PVP K17 solid dispersions were stabilized by hydrogen bonding but contained higher amount of residual dichloromethane (DCM) than poloxamer 407 formulations regardless of the method of preparation. SAS prepared oxeglitazar/poloxamer 407 dissolved more than two times faster than raw drug. However, unlike PVP K17, poloxamer 407 did not form a single phase amorphous solid solution with oxeglitazar which has been manifested in higher degrees of crystallinity, too. Among the two techniques, evaluated in this work, conventional coevaporation resulted in higher amorphous content but SAS reduced residual solvent content more efficiently. 相似文献
146.
Wolf C Lederer K Pfragner R Schauenstein K Ingolic E Siegl V 《Journal of materials science. Materials in medicine》2007,18(6):1247-1252
Adding the natural antioxidant α-tocopherol to ultra-high molecular weight polyethylene (UHMW-PE) can remarkably delay the
oxidation of hip cups made thereof. However, α-tocopherol is likely to undergo different chemical transformations during manufacturing
and sterilization of hip cups than in human metabolism. Therefore, the biocompatibility of the putative transformation products
has to be investigated. In-vitro tests with L929 mice fibroblast-cells gave no evidence for cytotoxicity. To further ensure
the biocompatibility, in-vitro tests with human cells were carried out in this study. Two different human cell lines, one
adherent cell line, HF-SAR, and one suspension culture, GSJO, were tested on UHMW-PE-tablets (diameter: 15 mm; thickness:
2 mm; processed according to standard procedures for artificial hip-cups) with and without α-tocopherol with respect to cell
viability, proliferation and morphology by means of cell counting, WSt-1 proliferation assay and scanning electron microscopy.
Similar proliferation rates were found with both polyethylene samples. Further, we found intact morphology in light and electron
microscopy on each substrate. The morphologic characteristics of skin fibroblasts were not changed by any material. Normal
adherence and spreading of the fibroblasts was found on controls of glass, as well as on polystyrene and on stabilized and
unstabilized polyethylene. The characteristic behaviour as suspension of the GSJO cells remained unchanged. The mitochondrial
activity, as studied by WST-1 cell proliferation reagent, was identical on each substrate during the whole observation period
of 7 days.
Christian Wolf—in partial fulfillment of a Ph.D. (Dr.mont.) thesis at the University of Leoben 相似文献
147.
Mireille Canal-Raffin Beatrice L'Azou Beatrice Martinez Elisabeth Sellier Fawaz Fawaz Philip Robinson Celine Ohayon-Courtès Isabelle Baldi Jean Cambar Mathieu Molimard Nicholas Moore Patrick Brochard 《Particle and fibre toxicology》2007,4(1):1-13
Background
Pesticides, in particular folpet, have been found in rural and urban air in France in the past few years. Folpet is a contact fungicide and has been widely used for the past 50 years in vineyards in France. Slightly water-soluble and mostly present as particles in the environment, it has been measured at average concentration of 40.1 μg/m3 during its spraying, 0.16–1.2 μg/m3 in rural air and around 0.01 μg/m3 in urban air, potentially exposing both the workers and the general population. However, no study on its penetration by inhalation and on its respiratory toxicity has been published. The objective of this study was to determine the physicochemical characteristics of folpet particles (morphology, granulometry, stability) in its commercial forms under their typical application conditions. Moreover, the cytotoxic effect of these particles and the generation of reactive oxygen species were assessed in vitro on respiratory cells.Results
Granulometry of two commercial forms of folpet (Folpan 80WG® and Myco 500®) under their typical application conditions showed that the majority of the particles (>75%) had a size under 5 μm, and therefore could be inhaled by humans. These particles were relatively stable over time: more than 75% of folpet remained in the particle suspension after 30 days under the typical application conditions. The inhibitory concentration (IC50) on human bronchial epithelial cells (16HBE14o-) was found to be between 2.89 and 5.11 μg/cm2 for folpet commercial products after 24 h of exposure. Folpet degradation products and vehicles of Folpan 80 WG® did not show any cytotoxicity at tested concentrations. At non-cytotoxic and subtoxic concentrations, Folpan 80 WG® was found to increase DCFH-DA fluorescence.Conclusion
These results show that the particles of commercial forms of folpet are relatively stable over time. Particles could be easily inhaled by humans, could reach the conducting airways and are cytotoxic to respiratory cells in vitro. Folpet particles may mediate its toxicity directly or indirectly through ROS-mediated alterations. These data constitute the first step towards the risk assessment of folpet particles by inhalation for human health. This work confirms the need for further studies on the effect of environmental pesticides on the respiratory system. 相似文献148.
High friction on a bubble mattress 总被引:2,自引:0,他引:2
Reducing the friction of liquid flows on solid surfaces has become an important issue with the development of microfluidics systems, and more generally for the manipulation of fluids at small scales. To achieve high slippage of liquids at walls, the use of gas as a lubricant--such as microbubbles trapped in superhydrophobic surfaces--has been suggested. The effect of microbubbles on the effective boundary condition has been investigated in a number of theoretical studies, which basically show that on flat composite interfaces the magnitude of the slippage is proportional to the periodicity of the gaseous patterns. Recent experiments aiming to probe the effective boundary condition on superhydrophobic surfaces with trapped bubbles have indeed shown high slippage in agreement with these theoretical predictions. Here, we report nanorheology measurements of the boundary flow on a surface with calibrated microbubbles. We show that gas trapped at a solid surface can also act as an anti-lubricant and promote high friction. The liquid-gas menisci have a dramatic influence on the boundary condition, and can turn it from slippery to sticky. It is therefore essential to integrate the control of menisci in fluidic microsystems designed to reduce wall friction. 相似文献
149.
Xavier Ravalec Nathalie Le Tallec François Carré Jacques D. de Certaines Elisabeth Le Rumeur 《Magma (New York, N.Y.)》1999,9(1-2):52-58
Kinetics of phosphoryl transfers from PCr to γ-ATP and from β-ATP to β-ADP were measured by magnetization transfer in an in
vivo31P NMR experiment in working rat skeletal hind leg muscles. Two groups were examined. One group was submitted to a 6-week training
program of treadmill running. The other group was composed of sedentary animals. Metabolic oxidative capacity and mechanical
performance were improved greatly by training as shown previously. Phosphoryl transfer of PCr→γ-ATP or β-ATP→β-ADP total fluxes
were identical in resting trained and untrained muscles. Under stimulation, the flux of creatine kinase transfer was significantly
inhibited by 23% compared with resting level in untrained muscles; by contrast, it was not inhibited and maintained at the
high resting level in trained muscles. Thus physiological changes probably linked to a decrease of the production of anions,
which could inhibit creatine kinase, were able to maintain creatine kinase flux. The flux of β-ATP to β-ADP transfer were
enhanced largely in working muscles from 1.4±0.8 and 2±0.8 at rest to 4±1.6 and 6.6±2.7 mM s−1 for untrained and trained muscles respectively; the effect was more pronounced in trained than in untrained muscles. These
results showed an acceleration of phosphoryl turnover in working muscles after training, which could contribute to improve
oxidative and mechanical performances. Such kinetic measurements of phosphoryl conversion may provide information on ATP turnover
in pathophysiologic situations where ADP accumulates because of impaired ATP synthesis (mitochondrial myopathies, lower perfusion
level). 相似文献
150.
Elisabeth Bardez 《Israel journal of chemistry》1999,39(3-4):319-332
When the acidic and basic groups of an amphoteric compound become stronger on excitation, excited-state proton transfers (ESPT) are driven by the photoinduced synergy between the two functions. This is exemplified here by 7- and 8-hydroxyquinolines (7- and 8-HQ), whatever the initially excited form. For instance, the -OH group of the 7-hydroxyquinolinium form undergoes photoinduced deprotonation even in 8M HClO4! This reveals its outstanding photoacidity, confirmed by the value of the deprotonation rate constant k1 at infinite dilution, 5.5 × 1010 s−1. The decrease of k1 on increasing the ionic strength pointed out the key number of 4 water molecules as proton acceptors. In neutral medium, a very efficient photoinduced tautomerization is observed. For 7-HQ in water, a mechanism consisting of three competitive paths was established: A proton translocation via a bridge of water molecules within less than 10 ps for the cis-isomer, and two stepwise competitive reactions for the trans-isomer. Concerning the weakly fluorescent 8-HQ, the photoinduced tautomerization occurs even in organic media. In most solvents, an intrinsic ESPT takes place within intramolecularly H-bonded molecules, but preferential solvation by residual water of the solvent may lead to open structures where ESPT is impaired. In alkanes, a biprotonic ESPT is expected to occur within very stable dimers (Kdim= 7.0 × 107). In all cases, the coupling between proton transfers and an intramolecular electron transfer leads to the ketonic structure of the tautomer. This might be a general feature in phototautomerization reactions. 相似文献