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21.
A nine-year old girl with T cell acute lymphoblastic leukemia (ALL) had acute severe neurologic complications at the end of the remission-induction chemotherapy course. Thirty-six hours following triple intrathecal (IT) therapy and intravenous (IV) administration of L-asparaginase (L-asp), tetraplegia developed and she became unconscious. She had bouts of hypertension and persistent tachycardia unresponsive to digitalis therapy. Magnetic resonance imaging (MRI) showed multiple brain white matter hyperintensities and filling defects in the saggital sinus, suggesting thrombosis. Over the 40 days, in addition to her neurologic compromise she also had transient diabetes mellitus, severe hyperlipidemia, hypoproteinemia and edema, liver and heart failure and staphylococcus aureus sepsis with prolonged bone marrow depression. Despite, coexistence of all these chemotherapy related complications, her neurologic functions and multiple organ failure improved gradually. After a 70 days' period of interruption, chemotherapy was resumed and continued without any further complications. Although, the etiology of her extensive sensitivity to some drugs remains unclear, we believe that it is important to document these unusual events in this child.  相似文献   
22.
There is a strong demand for an input switch in switched-capacitor circuits, covering rail-to-rail signal swing when low power-supply voltages are used. This brief proposes a novel clock-boosting scheme. The generated clock voltages of this new circuit are applied to a regular CMOS transmission gate to implement a simple and robust sampling switch when the supply voltages are very low. In this new approach, during the sampling phase, the gate-voltage of an nMOS switch is boosted up to V/sub dd/+k/spl middot/V/sub dd/, and the gate voltage of a pMOS switch is lowered to V/sub gnd/-k/spl middot/V/sub dd/, where k can be made programmable, and is usually smaller than 1. This allows sampling of the full signal swing, even when supply voltages are lower than |V/sub th/,p|+V/sub th/,n without applying extreme stress to the gate oxide of a transistor.  相似文献   
23.
The purpose of this study was to evaluate and compare the effect of Reciproc Blue (RPCB), XP‐endo Shaper (XPS), and WaveOne Gold (WOG) single‐files on dentinal microcrack formation using micro‐computed tomography (micro‐CT). Twenty‐four mesial roots (24 mesio‐buccal and 24 mesio‐lingual canals) of mandibular molar teeth were prepared using RPCB, XPS, and WOG files (n = 8/each group). The samples were scanned with micro‐CT in the pre‐ and post‐preparation. Then, before preparation and after preparation cross‐sectional images of the teeth were evaluated to detect the presence of microcracks. For each group, the number of microcracks was calculated as a percentage rate. The data were statistically analyzed using McNemar at 5% significance level (p < .05). Dentinal microcracks were observed in 25.99% (2,103 of 7,813), 31.99% (2,482 of 7,758), and 36.66% (2,836 of 7,731) of cross‐sectional images of the XPS, WOG, and RPCB groups, respectively. In all the groups, all the dentinal microcracks seen in the post‐treatment cross‐sectional images were present in the corresponding pre‐treatment images. Within the limitations of this study, the XPS, WOG, and RPCB files did not cause new dentinal microcrack formation or propagation of existing dentinal microcracks.  相似文献   
24.
A series aromatic polyimide (PI) membranes in the form of permselective films was synthesised from different dianhydrides with two diamine monomers for gallic acid (GA) measurement. The obtained PI films were examined by Spectroscopic techniques, Scanning Electron Microscopy (SEM) and thermal analysis techniques and then used to fabricate the selective films on the modified electrode. Because of their excellent film properties, as the permselective polymeric membranes were used for determination of GA in the presence of various interferences and real sample. The PI-1-modified Pt electrode showed a very high R-value (0.9935) and reproducibility for GA determination, as well as high selectivity.  相似文献   
25.
Electrical discharge machining (EDM) is a non-traditional production method that has been widely used in the production of dies throughout the world in recent years. The most important performance measure in EDM is the surface roughness; among other measures material removal and tool wear rates could be listed. In this study, experiments were performed to determine parameters effecting surface roughness. The data obtained for performance measures have been analyzed using the design of experiments methods. A considerably profound equation is obtained for the surface roughness using power, pulse time, and spark time parameters. The results are discussed.  相似文献   
26.
Journal of Materials Science: Materials in Electronics - The sol–gel technique was used to synthesize Er2?xCoxO3 (0.0?≤?x?≤?0.30) mixed oxides to...  相似文献   
27.
The impact of impregnation and bleaching on the hardness of varnish layers on oak (Quercus petraea L.) wood was investigated. A number of solutions [sodium hydroxide (NaOH) and hydrogen peroxide (H2O2); NaOH, calcium hydroxide, and H2O2; NaOH, magnesium sulfate, and H2O2; sodium bisulfate and H2C2O4 · 2H2; sodium silicate and H2O2; and potassium permanganate, sodium bisulfate, and H2O2] were applied at a concentration of 18% to bleach both impregnated [Tanalith‐CBC (T‐CBC) or Imersol‐WR 2000 (I‐WR 2000)] and unimpregnated (natural) wood panels. Subsequently, a water‐based varnish (WB) was coated over the samples, and the hardness of the varnished layers was determined in accordance with ASTM D 4366. Among the samples that were varnish‐coated without bleaching, T‐CBC/WB yielded the highest hardness (59.50), whereas I‐WR 2000/WB exhibited the lowest (49.17). However, among the samples varnish‐coated after bleaching, the highest (56.50) and lowest (40.83) varnish hardness values were obtained with T‐CBC/solution 2/WB and I‐WR 2000/solution 4/WB, respectively. All the chemicals used for the bleaching process reduced the surface hardness. However, after the varnish coating, except for solutions 4 and 6, all the solutions showed hardness values similar to those of varnish‐coated natural (control) samples. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 498–504, 2004  相似文献   
28.
In this study, the interaction of thionine, a cationic dye, with anionic [sodium dodecyl sulphate (SDS), lithium dodecyl sulphate (LiDS), and sodium dodecylbenzene sulphonate (SDBS)], nonionic (Tween 20 and Triton X‐100), and binary mixtures of anionic and nonionic surfactants was studied by conductometric and spectrophotometric measurements. The degree of ionisation, the counterion binding parameters, and the equilibrium constants in the premicellar region were obtained from conductivity data. Binding constants of thionine to anionic, nonionic, and mixtures of anionic and nonionic micelles were determined by spectrophotometric measurements. The binding tendency of thionine to anionic micelles followed the order SDBS > SDS > LiDS. The presence of nonionic surfactants increased significantly the binding affinity of thionine to anionic micelles, and the highest binding constant was calculated in the presence of Tween 20. The results obtained from conductometric studies correlated with those obtained from spectroscopic studies. Data concerning dye–surfactant interaction are important for a fundamental understanding of the performance of single and mixed surfactants and for their industrial application.  相似文献   
29.
This study was performed to determine whether some flexural properties of a denture base resin material could be improved through reinforcement with five types of aesthetic fibers at 3% concentration by weight and in 2, 4, and 6 mm length. Five specimens of similar dimensions were prepared for each of the test groups; base resin and the same resin with glass, rayon, polyester, nylon 6 and nylon 6,6 fibers in three different lengths. Flexural properties were evaluated by using a 3-point bending test. A visual examination was also made to determine mode of fracture of the specimens. The incorporation of different fibers in varying lengths had no significant effect on flexural strength of the resin. The specimens reinforced with nylon 6,6 fibers of 6 mm length showed the highest flexural strength. Young’s modulus and maximum load suggests that such reinforcement makes resin resistant to fracture.  相似文献   
30.
Mixed‐matrix membranes comprising NH2‐MIL‐53(Al) and Matrimid or 6FDA‐DAM have been investigated. The metal organic framework (MOF) loading has been varied between 5 and 20 wt%, while NH2‐MIL‐53(Al) with three different morphologies, nanoparticles, nanorods, and microneedles has been dispersed in Matrimid. The synthesized membranes have been tested in the separation of CO2 from CH4 in an equimolar mixture. At 3 bar and 298 K for 8 wt% MOF loading, incorporation of NH2‐MIL‐53(Al) nanoparticles leads to the largest improvement compared to nanorods and microneedles. The incorporation of the best performing filler, i.e., NH2‐MIL‐53(Al) nanoparticles, into the highly permeable 6FDA‐DAM has a larger effect, and the CO2 permeability increases up to 85% with slightly lower selectivities for 20 wt% MOF loading. Specifically, these membranes have a permeability of 660 Barrer with a CO2/CH4 separation factor of 28, leading to a performance very close to the Robeson limit of 2008. Furthermore, a new non‐destructive technique based on Raman spectroscopy mapping is introduced to assess the homogeneity of the filler dispersion in the polymer matrix. The MOF contribution can be calculated by modeling the spectra. The determined homogeneity of the MOF filler distribution in the polymer is confirmed by focused ion beam scanning electron microscopy analysis.  相似文献   
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