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排序方式: 共有605条查询结果,搜索用时 15 毫秒
51.
RO Darouiche A Dhir AJ Miller GC Landon II Raad DM Musher 《Canadian Metallurgical Quarterly》1994,170(3):720-723
To evaluate the adequacy of penetration of antibiotics into biofilm, a novel in vitro model for prosthesis-related infection was developed. Sterile stainless steel orthopedic nuts were incubated with slime-producing Staphylococcus epidermidis. Biofilm-covered nuts were exposed to varying concentrations of vancomycin; then biofilms were harvested. Vancomycin levels in biofilm, as measured by fluorescent polarization immunoassay, far exceeded the MIC and MBC of vancomycin for the organism. Bacterial growth in biofilm was inversely related to vancomycin concentration in biofilm, but even extremely high drug concentrations did not eradicate bacteria embedded in biofilm. The MICs and MBCs for bacteria recovered from biofilm did not differ from those for incubating organisms. Thus, failure of glycopeptide antibiotics to cure prosthesis-related infection is not due to poor penetration of drugs into biofilm but likely due to diminished antimicrobial effect on bacteria in the biofilm environment. 相似文献
52.
Hydrofluoroalkanes (HFAs) are used to replace chlorofluorocarbons (CFCs) as non-ozone-depleting propellants for pressurized metered-dose inhalers (pMDIs). HFA 134a and HFA 227 are used in combination to precisely manipulate the density and vapor pressure of pMDI formulations. The influence of propellant composition on the dose delivery characteristics of a suspension-based pMDI formulation was investigated. The results showed that as the density of the propellant blends approached the density of the suspended drug particles, the formulation became more physically stable and exhibited the most consistent dose delivery and greatest respirable fraction. The mass median aerodynamic diameter of the aerosolized particles contained in the emitted dose also was decreased by using propellant blends with higher vapor pressures. The performance of a suspension-based pMDI formulation was optimized by varying the propellant composition using HFA 134a and HFA 227. 相似文献
53.
54.
KD Wenstrom J Owen CG Brumfield RO Davis M Dubard T Garcia 《Canadian Metallurgical Quarterly》1997,90(6):938-942
We report our results in 24 children with malignant primary bone tumours of the distal femur treated with a Stanmore extendible endoprosthesis (SEER). This consists of a femoral component that can be lengthened, a constrained knee and an uncemented sliding tibial component which crosses the proximal tibial physeal plate perpendicularly. The average age of the patients at diagnosis was ten years and the mean follow-up was 4.7 years (2.5 to 7.9). The mean growth of the affected tibia was 76% (18 to 136) and of the fibula 83% (15 to 750) of the growth of the unaffected limb. Measurement of growth arrest lines showed that the mean growth of the proximal tibial physis on the affected side was 69% (43 to 100) of that of the normal side. The great variability in the growth of the physis cannot yet be explained. 相似文献
55.
MG Bhat LM Ganley DW Ledman MA Goodman RO Fox 《Canadian Metallurgical Quarterly》1997,36(40):12167-12174
In order to help determine the extent to which side chain interactions within the staphylococcal nuclease beta-barrel affect its global stability, a full set of point mutants was generated for residue 27. Intrinsic tryptophan fluorescence was monitored during solvent denaturation with guanidine hydrochloride (GuHCl) and was used to calculate DeltaGH2O unfolding and m values for each mutant. In the wild type protein, residue 27 is a tyrosine which is at the first position of a type I' beta-turn, and which participates in both hydrophobic interactions and side chain to side chain hydrogen bonding. The hydrophobicity of the mutant residue was found to be the dominant factor in determining global protein stability within this series of nuclease mutants. 相似文献
56.
Time‐of‐Flight Secondary Ion Mass Spectrometry (ToF‐SIMS) is a surface sensitive analytical method which is utilised in many scientific and industrial branches. The area of application is the identification and localisation of all elements as well as organic and inorganic chemical compounds on arbitrary solid surfaces. The information on the surface is obtained from mass spectra. Due to the high mass resolution (m/Δm > 5.000) different chemical species of the same nominal mass can be clearly separated from each other. Furthermore, the lateral distribution of elemental and molecular species on the surface can be displayed with a lateral resolution < 1 μm. By multivariate modeling the complete information from the mass spectra can be correlated with physical surface properties such as wetting behaviour, elemental concentrations, tribological parameters etc. The outcome of this are decisive information about the functionality of the analysed surface structure. For this reason Time‐of‐Flight Secondary Ion Mass Spectrometry becomes an essential analysis tool in the development of functional surfaces which are the basis of novel and innovative products. 相似文献
57.
DS De Wachter PR Verdonck JY De Vos RO Hombrouckx 《Canadian Metallurgical Quarterly》1997,20(7):366-370
To investigate the haemolysis in haemodialysis cannulae, an in-vitro set up is built, using a unipuncture dialysis system. This system is connected to a bag with fresh calf's blood, by the cannula under test, mounted in a large bloodline (5 mm diameter). The blood characteristics are kept constant by means of a bicarbonate dialysate in the dialyser. During a 6 h period, haematological parameters are regularly samples. Flow through the cannulae is recorded, which is about 500 mL/min. Four different cannulae are tested and compared to the results obtained without any cannula in the circuit. In all cases a linear increase in plasma free haemoglobin levels is found after 6 h. The cannulae can be ranked from 8F catheter over 13G, 14G to 16G cannula, the latter producing the highest degree of haemolysis. When using plastic cannulae at high blood flows, their haemolytic effect may not be neglected. 相似文献
58.
59.
E Jacoby 《Canadian Metallurgical Quarterly》1998,106(4):A170-A171
60.
In the insulin producing cell line RINm5F distribution of serine/threonine specific protein phosphatases type 1 (PP1) and 2A (PP2A) was studied. Using different agents which inhibit or stimulate PP1 and PP2A we found that in membrane and nuclear fractions phosphatase activity was inhibited by okadaic acid (OA), protamine, heparin, and inhibitor-2 in a concentration-dependent manner. C2-ceramide had no effect. In the cytosolic fraction the inhibitory effect of okadaic acid was tenfold higher. Protamine stimulated phosphatase activity at low concentrations and became inhibitory at higher concentrations. Inhibitor-2 and heparin caused a decrease in phosphatase activity whereas C2-ceramide led to a slight activation. The data suggest that in membrane and nuclear fractions of RINmSF cells predominantly PP1 is present, whereas in the cytosol PP1 as well as PP2A can be detected. 相似文献