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Objective To observe the effect of different doses of ε-aminocaproic acid （EACA） on wound bleeding in infants undergoing cleft palate repair. Methods One hundred and twenty infants scheduled to undergo cleft palate repair， aged from 6 to 36 months， ASA status Ⅰ or Ⅱ， were randomly divided into the control （group C）， conventional-dose EACA （group E1） and low-dose EACA groups （group E2）， 40 cases in each group. Infants in groups E1 and E2 were administrated with a loading dose of EACA （40 mg/kg） for 20 min before incision， followed by continuous infusion of 30 mg/（kg·h） and 10 mg/（kg·h） in two groups， respectively. In group C， continuous infusion of normal saline was applied. Same anesthesia regimen was delivered for all patients among three groups. Wound bleeding scores during operation， before extubation and 24 h after operation， intraoperative blood loss， anesthesia time， operation time， and fibrinogen concentration before and 24 h after surgery， and the incidence of delayed haemorrhage， deep vein thrombosis and epilepsy were recorded. Results Compared with group C， the wound bleeding scores during operation and before extubation in group E1 and E2 were significantly lower， the amount of intraoperative blood loss was significantly less， and the fibrinogen concentration at postoperative 24 h was significantly increased （all P < 0.05）， while no significant statistical difference was observed between groups E1 and E2 （all P > 0.05）. There were no statistically significant differences in operation time， anesthesia time and the incidence of delayed hemorrhage among three groups （all P > 0.05）. No deep vein thrombosis or epilepsy occurred among three groups. Conclusion The application of EACA in infants with cleft palate repair can mitigate perioperative wound bleeding and lower the incidence of delayed hemorrhage. Low-dose EACA yields favorable hemostatic effect. These findings provide reference for drug use in clinical practice.

The ternary carbide Ti3AlC2 was reactively synthesized from the elemental powder mixtures of Ti, Al and activated carbon. Cu/Ti3AlC2 composites were fabricated by hot-pressing method. Their microstructures and properties were investigated. The results demonstrated that Ti3AlC2 is a promising reinforcement for copper and the Cu/Ti3AlC2 composites exhibited lower electrical conductivity and much superior flexural strength to pure copper matrix without remarkable loss of fracture toughness. [Copyright &y& Elsevier]

Abstract: The eutectic PbTe–Sb2Te3 composite with self-organized lamellar structure was synthesized using induction melting and the effects of annealing on the microstructure and thermoelectric properties were investigated. The PbTe and Sb2Te3 lamellae are crystallographically oriented with coherent interface, which are found to insignificantly affect the electronic flow. After annealed, the spheroidization of the lamellae occurs, and the carrier concentration decreases. Despite the increased phase boundaries, the lattice thermal conductivity increases with the annealing time. Largely due to the enhanced Seebeck coefficient, a maximum ZT ∼ 0.48 at 550 K for the sample annealed for 20 h at 573 K is achieved, showing a 60% improvement over that of the as-melted one. [Copyright &y& Elsevier]

Based on the DFT theory and first-principles calculations, we found that both the oscillatory relaxed surface geometry and Ag–Sb doping configuration exert prominent effects on the electronic properties and doping stability of an Ag–Sb co-doped PbTe (100) surface. Ag and Sb atoms tend to form Ag–Sb nanodots in the subsurface layers and the thermoelectric performance of PbTe may be improved through Ag–Sb doping into PbTe thin film due to the enhancement and distortion of the density of states near the Fermi level. [ABSTRACT FROM AUTHOR]

The microstructure, oxidation state and thermoelectric transport properties of Mg and Pb co-doped p -type Bi 1–2 x Mg x Pb x CuSeO oxyselenides have been investigated. Pure single BiCuSeO phase are obtained for all the samples without preferential growth in the crystallites. X-ray photoelectron spectroscopy (XPS) results indicate that both Mg and Pb dopants are in the 2+ oxidation state whereas other than the expected Bi 3+ , higher-oxidation-state Bi ions also exist in both the pristine and doped BiCuSeO compounds. The Mg and Pb co-doping yields a remarkable enhancement in the electrical conductivity coupled with a moderate Seebeck coefficient. A pronounced increment in power factor is achieved from 2.54 μW cm −1 K −2 for the pristine BiCuSeO to 11.1 μW cm −1 K −2 for Bi 0.88 Mg 0.06 Pb 0.06 CuSeO at 750 K. In addition to increasing the power factor, Mg and Pb co-doping reduces the lattice thermal conductivity owing to the dopant-induced point defect scattering of phonon. The combination of optimized power factor and intrinsically low lattice thermal conductivity results in a high Z T of 1.19 at 750 K for Bi 0.88 Mg 0.06 Pb 0.06 CuSeO, which is about 3.1 times as large as that for the pristine BiCuSeO. [ABSTRACT FROM AUTHOR]

The thermoelectric properties and electronic structures were investigated on p -type BiCu 1- x Ag x SeO ( x =0, 0.02, 0.05, 0.08) ceramics prepared using a two-step solid state reaction followed by inductively hot pressing. All the samples consist of single BiCuSeO phase with lamella structure and no preferential orientation exists in the crystallites. Upon replacing Cu + by Ag + , maximum values of electrical conductivity of 36.6 S cm −1 and Seebeck coefficient of 350 μV K −1 are obtained in BiCu 0.98 Ag 0.02 SeO and BiCu 0.92 Ag 0.08 SeO, respectively. Nevertheless, a maximum power factor of 3.67 μW cm −1 K −2 is achieved for BiCu 0.95 Ag 0.05 SeO at 750 K owing to the moderate electrical conductivity and Seebeck coefficient. Simultaneously, this oxyselenide exhibits a thermal conductivity as low as 0.38 W m −1 K −1 and a high ZT value of 0.72 at 750 K, which is nearly 1.85 times as large as that of the pristine BiCuSeO. The enhancement of thermoelectric performance is mainly attributed to the increased density of states near the Fermi level as indicated by the calculated results. [ABSTRACT FROM AUTHOR]

Abstract: The microstructures, tensile properties and creep behavior of the Cr- and Mo-microalloyed Ti–Ti3Al–Nb alloys processed by directional solidification were investigated. The experimental results indicated that the strength, ductility and creep resistance of ternary Ti–Al–Nb alloy were remarkably enhanced by additions of small amounts of Cr and Mo. The stress exponent for creep showed a transition and varied from a lower value of 3.5–5.3 (LSR-region I) to a higher value of 8.3–12.6 (HSR-region II) with increasing stress at 600 and 650°C whereas a single stress exponent value of 5.3–6.0 was obtained at 700°C. Conversely, the true activation energy for creep was calculated to be 303–324kJ/mol and fell into or was quite close to that for the self-diffusion of Ti in α2-Ti3Al (288–312kJ/mol). TEM examinations revealed that ordinary dislocations in the lath dominated the deformed microstructures. However, the initial microstructure of the alloys was unstable during long-term creep exposure and dynamic recrystallization occurred at high stress and moderately high temperature. The creep deformation in region I was dislocation-controlled whereas the abnormally high stress exponent in region II was associated with the effects of recrystallization resulting in a reduction in the overall grain size of the initial structure. The fracture modes and total strain were dependent on the composition, test temperature, and stress level. The accelerating strain rate in the extended tertiary stage was attributed to the microstructural instabilities or the nucleation, coalescence and merge of voids or microcracks. [Copyright &y& Elsevier]