Use of modified Ilizarov olive wires as pushing wires

BACKGROUND: Measurements of cardiac output with the thermodilution technique add to data for clinical decision making and therefore must be valid and reliable. However, the results of studies on the accuracy of values obtained with room-temperature and iced injectates, especially in patients with high or low cardiac output, have been conflicting. OBJECTIVE: To determine the effect of the temperature of the injectate (iced or room temperature) on cardiac output values obtained with the thermodilution technique in critically ill adults with known low cardiac output. METHODS: A convenience sample of 50 subjects (41 men and 9 women) who had a cardiac index of less than 2.5 (calculated as cardiac output in liters per minute divided by body surface area in square meters) before the study had cardiac output measured by using a closed system and manual injections of room-temperature and iced injectates. RESULTS: A paired t test indicated no significant difference between iced and room-temperature injectates for cardiac output (iced, 3.62 L/min; room temperature, 3.71 L/min; t = 0.99; P = .327) and cardiac index (iced, 1.95; room temperature, 1.99; t = 0.71; P = .482). CONCLUSION: The findings support the practice of using room-temperature injectate to measure cardiac output in patients with low cardiac output.     

Fracture of drawn tungsten wires

Conditions that govern the process of fracture in fibrous material were examined with fine, heavily deformed tungsten wires. In particular, the nature of interaction between fiber rupture and delamination in the fracture process was determined by deforming wires under different loading conditions. This was accomplished by testing fine wires under simple uniaxial and “bend-and-stretch” loading conditions so that the effective stress state could be altered in the deforming fibers. Results of mechanical testing and scanning electron microscopy examination indicated that the process of fracture was controlled by fiber rupture but only to the extent that it could be accommodated by the delamination of fiber interface. The degree of the delamination process in turn was dependent on the magnitude of the radial stress in outer fibers. This view point was supported by an experiment with wires that contained surface flaws.     

Subgrain strengthening of aluminum conductor wires

The influence of wire processing variables on the formation of subgrain structures and strengthening in three aluminum conductor materials is described. Electrical conductor grade aluminum, an Al-Fe-Mg alloy and an Al-Fe-Co alloy each develop subgrain structures with mean linear intercepts (•L) in the range of 0.4 to 1.5 μm with several sequences of wiredrawing and partial annealing. The yield strengths of these wires were found to obey a a = σ₀ +k(•L) ^m relationship, with an exponentm = -1 independent of the processing sequence used to arrive at the structure. The role of precipitate particles in the alloys is to raisek above that for EC-A1 while Mg in solid solution increases σ₀. The precipitates also affect the development of the substructure during the wiredrawing and annealing.     

Secondary recrystallization of pure molybdenum wires

The secondary recrystallization of drawn pure Mo wires has been studied; a particular attention has been paid on the effect of temperature gradients in the annealing process. The secondary recrystallized grains being very elongated along the wire axis have been obtained by annealing in a moderate temperature gradient furnace at about 2000°C. Orientations of the wire axis of the secondary recrystallized grains are mainly 〈023〉 or 〈135〉, while 〈011〉 oriented grains are less frequently observed. In contrast, the primary recrystallized texture consists of the 〈011〉 main component and 〈023〉-〈012〉 sub-component; many 〈011〉 oriented grains have large grain sizes. The observed discrepancy in orientation between the primary and secondary recrystallized grains is explained in terms of the difference in grain boundary mobilities which depend on the character of grain boundaries.     

Subgrain strengthening of aluminum conductor wires

The influence of wire processing variables on the formation of subgrain structures and strengthening in three aluminum conductor materials is described. Electrical conductor grade aluminum, an Al-Fe-Mg alloy and an Al-Fe-Co alloy each develop subgrain structures with mean linear intercepts (?L) in the range of 0.4 to 1.5 μm with several sequences of wiredrawing and partial annealing. The yield strengths of these wires were found to obey a a = σ₀ +k(?L)^m relationship, with an exponentm = -1 independent of the processing sequence used to arrive at the structure. The role of precipitate particles in the alloys is to raisek above that for EC-A1 while Mg in solid solution increases σ₀. The precipitates also affect the development of the substructure during the wiredrawing and annealing.

     

Circular dichroism of DNA frayed wires

Ultraviolet circular dichroism spectra are reported for the oligonucleotide d(A15G15) in aqueous solutions containing 5 mM MgCl2 at several temperatures and in the presence of partially complementary oligonucleotides. Oligonucleotides with several consecutive terminal guanine residues self-associate to form aggregates, called frayed wires, that consist of integer numbers of strands. A "stem" is formed through interactions between the guanine residues of the associated oligonucleotides, whereas the adenine "arms" remain single stranded. Upon subtracting the circular dichroism spectrum of d(A15) from that of d(A15G15), one obtains a spectrum that closely resembles previously published spectra of poly(G). Subtracting spectra measured at temperatures between 10 degrees C and 60 degrees C reveals the resultant spectra to be independent of temperature, consistent with the extreme thermal stability observed for the aggregated structures. Upon the addition of d(T15) to the solution, complexes with the adenine portion of the d(A15G15) frayed wires are formed. Subtraction of d(A15):d(T15) spectra measured at several temperatures from those of the d(A15G15):d(T15) does not significantly alter the spectrum of the guanines. The helix-coil transition temperature of d(A15):d(T15) duplex is identical to that of the unbinding of d(T15) from d(A15G15):d(T15) complexes. Experiments using oligonucleotides in which the adenines were replaced with sequences of bases yielded similar results. By varying the length of the nonguanine tract, it is shown that the solubility of the complexes increases with the length of the nonguanine region of the oligonucleotide.