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81.
Donor human milk is pasteurized to prevent the potential risk of the transmission of pathogens to preterm infants. Currently, Holder pasteurization (human milk held at 62·5°C for 30 min) is used in most human milk banks, but has the disadvantage that it results in excessive inactivation of important bioactive components. Power-ultrasound (20-100 kHz) is an emerging technology for the preservation of foods and could be an alternative method for the treatment of human milk. The aim of this study was to investigate the effect of different ultrasound settings on the elimination of Escherichia coli and the retention of bile salt stimulated lipase (BSSL) activity. Ultrasonication with a constant power decreased Esch. coli viability exponentially over time until the processing temperature increased to sub-pasteurization level to between 51·4 and 58·5°C, then a log10 1·3 decrease was observed (P<0·05). BSSL activity decreased to 91% until a temperature of 51·4°C and then it decreased to 8% between 51·4 and 64·9°C. Ultrasonication with a constant energy and various power and exposure times showed the highest temperature (53·7°C) when treated with the longest exposure time and lowest ultrasound-power (276 s at 3·62 W) compared with 37·6°C for 39 s at 25·64 W. The findings predict that the viability of Esch. coli could be reduced by log10 5 with a minimal loss of activity of BSSL by applying 13·8 kJ of energy in 12 ml of human milk using high ultrasound power over a short exposure time to ensure that the temperature remains below the critical level for protein denaturation. Alternatively, the use of lower power settings such as the 26 W used in the present studies would require a cooling system to ensure the human milk BSSL was protected against temperature denaturation. 相似文献
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83.
H.-M. Christen K.S. Harshavardhan M.F. Chisholm E.D. Specht J.D. Budai D.P. norton L.A. Boatner I.J. Pickering 《Journal of Electroceramics》2000,4(2-3):279-287
Epitaxial, uniformly strained superlattices of ferroelectric KNbO3 and paraelectric KTaO3 are studied with respect to their structural and dielectric properties. For dielectric measurements, perfectly lattice-matched conducting KNbO3Sr(Ru0.5Sn0.5)O3 electrodes are used, and a broad, frequency-dependent maximum is observed in the capacitance-vs-temperature curves. Niobium K-edge glancing-angle EXAFS provides information regarding the crystal structure of KNbO3 films as thin as two unit cells in superlattices with equal KTaO3 and KNbO3 layer thicknesses, showing a clear difference between these thinnest-layer superlattices and films of the KNbO3K(Ta0.5Nb0.5O3 solid-solution. X-ray diffraction measurements, on the other hand, indicate that these samples exhibit the same transition temperature KNbO3Tc, indicating the importance of long-range electrostatic interactions. Analysis of the transition temperature for various structures leads to a clear identification of the effect of size and strain on KNbO3Tc. 相似文献
84.
The formation of oxidation-resistant buffer layers on (001) oriented Cu for coated high-temperature superconducting tape applications was investigated. The approach employed Cu/Mg multilayer precursor films that were subsequently annealed to form either Mg-doped fcc Cu or intermetallic Cu2 Mg. The precursor consisted of an Mg/Cu multilayer stack with 5 each of 25 nm thick Mg and 25 nm thick Cu layers which were grown at room temperature by sputter deposition. At annealing temperature of 400 °C, formation of the intermetallic Cu2 Mg was observed. X-ray diffraction showed that the Cu2 Mg (100) oriented grains were epitaxial with respect to the underlying Cu film, possessing a cube-on-cube orientation. In order to test oxidation resistance, CeO2 films were deposited at elevated temperature on Ni/(Cu,Mg)/Cu/MgO structures. In case of the CeO2 film on Ni/Cu/MgO, significant surface roughness due to the metal oxidation is observed. In contrast, no surface roughness is observed in the SEM images for the CeO2/Ni/(Cu,Mg)/Cu/MgO structure. 相似文献
85.
The growth of epitaxial MgO/TiN multilayer films on (001) Cu has been investigated. In particular, epitaxial structures were grown on (001) Cu layers that were epitaxial on (001) SrTiO3. X-ray diffraction and reflection high-energy electron diffraction indicate that the multilayer structures are epitaxial on the (001) Cu surface. The motivation is the use of crystalline MgO/TiN multilayers as a diffusion barrier to both copper and oxygen. MgO/TiN multilayers are potentially useful as diffusion barriers for Cu interconnects on semiconductors as well as for superconducting wires based on the epitaxial growth of cuprate superconductors on biaxially textured copper. 相似文献
86.
Low-pressure plasma discharges can be applied to remove various biomolecules from surfaces. However, the knowledge on the interaction between plasma and biomolecules and the kinetics of their removal is still rather poor, which is a major limiting factor for the optimization of this type of plasma treatment. This is, among other reasons, because of the restrictions of currently used techniques for the evaluation of the rates of biomolecule removal during plasma treatment. Therefore, an alternative method based on imaging ellipsometry is applied in this study. It is shown that this method allows reliable semi-quantitative comparison of the treatment efficiency of plasma discharges sustained in different gas mixtures. 相似文献
87.
Fabrication of Long Lengths of Epitaxial Buffer Layers on Biaxially Textured Nickel Substrates Using a Continuous Reel-to-Reel Dip-Coating Unit 总被引:2,自引:0,他引:2
M. Parans Paranthaman Thomas G. Chirayil Fred A. List Xingtian Cui Amit Goyal Dominic F. Lee Eliot D. Specht Patrick M. Martin Robert K. Williams Donald M. Kroeger Jonathan S. Morrell David B. Beach Ron Feenstra David K. Christen 《Journal of the American Ceramic Society》2001,84(2):273-78
A low-cost, nonvacuum, solution precursor route has been developed to produce epitaxial oxide buffer layers of Eu2 O3 or La2 Zr2 O7 on biaxially textured Ni (100) tapes. A reel-to-reel continuous dip-coating unit consisting of a constant-tension tape transport system attached to a controlled atmosphere furnace was fabricated. Nickel tapes were pulled through a 2-methoxyethanol solution of europium methoxyethoxide/acetate or lanthanum zirconium methoxyethoxide. The double-sided dip-coated tapes were then annealed in a preheated furnace at 1000°–1100°C with a high flow rate of Ar/H2 (4%) gas. The dip-coated buffers were dense, continuous, crack-free, and epitaxial with a single cube texture. A critical current ( J c ) of >1 MA/cm2 at 77 K and self-field was obtained for YBa2 Cu3 O7-δ (YBCO) films with a layer sequence of YBCO ( ex situ BaF2 process)/CeO2 (sputtered)/YSZ (sputtered)/Eu2 O3 (dip-coated)/nickel. We have produced 1–2 m lengths of epitaxial buffer layers on textured nickel substrates using a nonvacuum process for the first time. 相似文献
88.
MD Ries LA Rauscher S Hoskins D Lott JA Richman F Lynch 《Canadian Metallurgical Quarterly》1998,(356):154-160
Twenty-eight patients who underwent unilateral total knee arthroplasty and 20 patients who underwent simultaneous bilateral total knee arthroplasties participated in this study and were randomized to have either a fluted or round 10-mm diameter femoral intramedullary alignment rod used during surgery. The intramedullary rods were cannulated and connected with pressure tubing to a monitor which provided measurements of pressure at the tip of each rod. Arterial blood gas measurements on room air were obtained before and on the morning after surgery. An arterial line was placed and an arterial blood gas measurement was obtained at the time of skin incision and again after tourniquet release. Pulmonary shunt was calculated from the arterial blood gas measurements. Intramedullary pressure during rod insertion was significantly higher for the groups of patients having the round compared with the fluted rod. The change in pulmonary shunt during surgery was lowest for the patients in the unilateral group having the fluted rod and highest for the patients in the bilateral group having the round rod. A fluted rather than a round intramedullary alignment rod should be used to minimize intramedullary pressure and pulmonary shunting during unilateral and bilateral total knee arthroplasties. 相似文献
89.
90.