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31.
Magnetic resonance (MR) imaging provides useful information in the evaluation of peripheral nerves. Recent advances in MR imaging allow for detailed depiction of the soft tissue structures of the elbow joint. Three major nerves are present about the elbow. Six cadaveric elbows were imaged to depict the normal anatomy of these nerves and to determine the best plane and position of the elbow for optimal visualization of each nerve. Axial images of the elbow in full extension with the forearm in supination allow identification of all major nerves. Axial images with the elbow in full flexion allow accurate assessment of the cubital tunnel and the ulnar nerve. Axial images of the elbow in full extension with the forearm in pronation are helpful for assessment of the median and radial nerves in the forearm.  相似文献   
32.
Bruton's tyrosine kinase (Btk) is essential for normal B lymphocyte development and function. The activity of Btk is partially regulated by transphosphorylation within its kinase domain by Src family kinases at residue Tyr-551 and subsequent autophosphorylation at Tyr-223. Activation correlates with Btk association with cellular membranes. Based on specific loss of function mutations, the Btk pleckstrin homology (PH) domain plays an essential role in this activation process. The Btk PH domain can bind in vitro to several lipid end products of the phosphatidylinositol 3-kinase (PI 3-kinase) family including phosphatidylinositol 3,4,5-trisphosphate. Activation of Btk as monitored by elevation of phosphotyrosine content and a cellular transformation response was dramatically enhanced by coexpressing a weakly activated allele of Src (E378G) and the two subunits of PI 3-kinase-gamma. This activation correlates with new sites of phosphorylation on Btk identified by two-dimensional phosphopeptide mapping. Activation of Btk was dependent on the catalytic activity of all three enzymes and an intact Btk PH domain and Src transphosphorylation site. These combined data define Btk as a downstream target of PI 3-kinase-gamma and Src family kinases.  相似文献   
33.
An AIDS patient with disseminated histoplasmosis who improved during treatment with fluconazole but remained fungemic and subsequently relapsed is described. Isolates obtained from blood during therapy showed a progressive increase in fluconazole MIC from 0.625 to 20 micrograms/ml. The pretreatment, or parent, isolate and the posttreatment, or relapse, isolate demonstrated identical genetic patterns by PCR fingerprinting with three different primers. Fluconazole was less potent inhibitor of the growth of the relapse isolate than of the pretreatment isolate (50% inhibitory concentration [IC50] = 11.7 microM), while itraconazole was more potent (relapse isolate IC50 = 0.0011 microM versus pretreatment isolate IC50 = 0.0064 microM). Neither the increased sensitivity to itraconazole nor the decreased activity of fluconazole on the growth of the relapse isolate results from changes in the intracellular content of these agents. To reach 50% inhibition of ergosterol synthesis in both the parent and relapse isolates, about 2 nM itraconazole was needed; with fluconazole, 50% inhibition was achieved at 20.9 microM and 55.5 microM, respectively. Resistance to fluconazole may develop during treatment and results from decreased sensitivity of ergosterol synthesis.  相似文献   
34.
OBJECTIVE: To discuss the case of an 8-yr-old boy with an aneurysmal bone cyst of the right proximal humerus, including the features imaged on plain film radiography, computed tomography (CT), magnetic resonance imaging (MRI), including spin echo and fast field echo imaging. CLINICAL FEATURES: The patient suffered for 1 yr from intermittent but progressive pain in his right upper arm and shoulder area. There was no history of trauma or known systemic disease. There was decreased range of motion in abduction of the glenohumeral joint and pain on focal pressure along the deltoid muscle. A complete imaging evaluation consisting of plain film radiography, CT and MRI was performed, which revealed the classical imaging features of an aneurysmal bone cyst. An additional cystic lesion was detected by the MRI that was not appreciated on the plain films or CT. INTERVENTION AND OUTCOME: The patient was referred for biopsy to confirm the preliminary diagnosis of aneurysmal bone cyst. No treatment was instituted. CONCLUSION: Evaluation of aneurysmal bone cyst may be completed with CT scanning and more specifically with MRI MRI coronal T2, weighted images are advantageous for visualization of the main cystic lesion and any additional cysts. Fast field echo images show a better contrast between the cyst and bone marrow with extension of the cyst into the epiphysis as evident in this case. Follow-up studies revealed complete healing of the cyst with only residual densities in the humeral metaphyseal area.  相似文献   
35.
Rods of commercially pure titanium were machined using standard oil-based emulsion and cryogenic cooling, and were then coated with sphene (CaTiSiO5) bioceramic by spray coating using an automatic airbrush. The sphene bioceramic was synthesized in-situ starting from a suspension of polysiloxane that used as SiO2 precursor, CaCO3 and TiO2 nanoparticles. The suspension was deposited on the machined substrates, which were heat treated up to 950?°C in order to promote the formation of sphene ceramic. The produced coated prototypes were characterized to evaluate the effect of the machining conditions on surface roughness and microstructure of the substrate, and thereby their effect on coating adhesion. Nanoindentation tests were employed to determine the hardness and elastic modulus of the coating through its thickness. Results showed that the reduced amount of defects on the surface of the cryo-machined substrates, contributed to increase the hardness, elastic modulus and adhesion strength of the coating-substrate interfaces compared to standard machined samples, therefore improving adhesion of the coating to the underlying substrate.  相似文献   
36.
Constant  L.  Ruiz  P.  Abel  M.  Robach  Y.  Porte  L.  Bertolini  J.C. 《Topics in Catalysis》2000,14(1-4):125-129
The catalytic properties, with respect to the 1,3-butadiene hydrogenation reaction, of strained Pd films on Cu(110) (lattice mismatch 8%) has been probed as a function of the film thickness. The characterization of the adlayer has been made by the combined use of STM with LEED and AES. For deposits below 1015 Pd/cm2 (i.e., about 1 ML) the catalytic activity is near zero. This is the consequence of the formation of a Pd–Cu surface alloy with tendency for Cu to migrate/segregate to the surface. The catalytic activity suddenly increases to reach a maximum value for about 3 ML; the activity is then one order of magnitude higher than that of the pure Pd(110) surface. This is the consequence of the presence of a strained Pd overlayer, with Pd surface atoms having very unusual geometry, and hence very peculiar electronic and chemical properties. The catalytic activity then decreases as the Pd coverage is increased, and tends to values near that of the pure Pd(110). Gradual relaxation of the film geometry towards that of the normal fcc Pd structure probably exists.  相似文献   
37.
Techniques based on electroosmosis have been proposed as restoration methods to reduce the moisture content in masonry subjected to capillary suction. Although several applications have been reported in the literature and beneficial effects of electroosmosis are often claimed, very little technical information is available. Quite rarely quantitative measurements of humidity changes in the masonry following the application of the current are reported. This paper reports the results of a research work aimed at studying the electroosmotic transport through porous construction materials, in order to investigate the factors that influence electroosmosis and define its actual technological applicability for the rehabilitation of damp masonry. The experimental tests showed that, for several concomitant circumstances, the chances that the technique based on electroosmosis might be effective in drying damp masonry are extremely low.  相似文献   
38.
39.
BACKGROUND: Auxiliary liver transplantation has several advantages over standard orthotopic liver transplantation. However, functional competition has been reported even in auxiliary partial orthotopic liver transplantation (APOLT). We evaluated herein the interaction in APOLT between the native liver and the graft in terms of portal blood flow and regeneration. The need for diversion of the portal blood flow to the graft was also assessed. METHODS: A total of 15 patients received APOLT from living donors. Portal blood flow to the native liver was preserved in 6 patients, and the portal vein to the native liver was preemptively transected at the time of transplantation in 9 patients. RESULTS: Of the patients with preservation of the portal blood flow to the native liver, two showed inadequate graft portal blood flow just after operation, and in the other three patients the graft portal blood flow decreased or the graft atrophied after deterioration of the graft function. In the patients with preemptive transection of the portal vein to the native liver, optimal graft portal blood flow was obtained, and the native liver, supplied only by arterial inflow, supported a small-for-size graft until the graft regenerated. The damage to the native liver was minimal. CONCLUSIONS: Functional competition may occur in APOLT with preservation of the portal blood flow to the native liver, whereas preemptive transection of the native liver portal vein is a safe procedure and effectively prevents the portal steal phenomenon.  相似文献   
40.
OBJECTIVES: Little information is available about the intake of very-long-chain n-3 fatty acids in random samples of populations. We examined if the intake of these fatty acids was associated with gender, social status and lifestyle in a similar way as other indicators for a healthy diet in a nationwide survey. DESIGN AND SUBJECTS: Data were obtained from self-administered quantitative food frequency questionnaires filled in by a representative sample of Norwegian men and women, aged 16-79 y. 3144 (63%) of the invited subjects responded with acceptable questionnaires. RESULTS: Daily intake of very-long-chain n-3 fatty acids was on average 0.9 g/d and 0.4% of total energy was derived from these fatty acids. Energy derived from very-long-chain n-3 fatty acids was slightly higher among men than women, and two-fold higher among subjects aged 60-79 vs 16-29 y. White collar workers had higher intake of very-long-chain n-3 fatty acids than blue collar workers. Men and women in the highest quartile of intake of very-long-chain n-3 fatty acids had 2-3 E% higher fat intake (mostly mono- and polyunsaturated fatty acids), as compared to individuals in the lowest quartile. They also had 3-4 fold higher daily intake of retinol and vitamin D, as well as 20-50% higher intake of fruits and vegetables, dietary fibre and vitamin C. CONCLUSIONS: Intake of very-long-chain n-3 fatty acids was correlated to indicators for healthy dietary habits. However, contrary to many other indicators of a healthy diet, energy derived from very-long-chain n-3 fatty acids was not significantly associated with female gender or non-smoking.  相似文献   
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