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OBJECTIVE: To assess the effect of a 3 month behaviour modification weight management programme on self-efficacy and anthropometric variables among obese women seeking treatment at an obesity management clinic and to compare self-efficacy among these obese women to non-obese women. DESIGN: Cross sectional. SUBJECTS: A total of 161 non-obese (BMI 22.6 ± 2.9 kg/m²) and 138 obese (BMI 37.7 ± 5.8 kg/m²) women of similar age. MEASUREMENTS: Self-efficacy in relation to eating was assessed by the Weight Efficacy Lifestyle (WEL) questionnaire. Demographic information was obtained by interview and questionnaire in the obese and by questionnaire in the non-obese. Anthropometric measurements were obtained by direct measure in the obese and BMI was calculated from self-reported weight and height in the non-obese. RESULTS: At entry to the programme obese women scored significantly less (P < 0.0001) than non-obese women on the WEL (99.4 ± 34.1 vs 139.0 ± 24.9). Women who completed the programme (n=65) demonstrated a decrease in waist circumference of 3.9 ± 5.3 cm, a 10.0 ± 11.5% loss of excess weight and a significant improvement in total WEL score from 106.0 ± 30.3 to 126.5 ± 28.4. CONCLUSION: Improvements in some dimensions of self-efficacy among obese women were of sufficient magnitude to attain scores similar to women of a normal weight. The WEL questionnaire may provide an additional measure of success as well as provide positive feedback and encouragement to the client. [ABSTRACT FROM AUTHOR]

Recent international research has resulted in the development of superclean 3.5NiCrMoV steel for low pressure turbine rotors. Such steel is highly resistant to temper embrittlement and will thus facilitate increased efficiency in electricity generation through the use of higher operating temperatures and improvements in design. Steels with impurity contents typical of the superclean specification can be manufactured for production rotors with properties that equal or exceed those for conventional 3.5NiCrMoV rotors in every detail. Of particular interest are the observations that the superclean steels appear to be virtually immune to temper embrittlement and may be used up to their creep limited temperature of 500° C (932° F). An introduction to the steelmaking practices and heat treatments used to produce full sized production rotors is presented in this paper along with resulting metallurgical properties. [ABSTRACT FROM AUTHOR]

Recent international research has resulted in the development of superclean 3.5NiCrMoV steel for low pressure turbine rotors. Such steel is highly resistant to temper embrittlement and will thus facilitate increased efficiency in electricity generation through the use of higher operating temperatures and improvements in design. Steels with impurity contents typical of the superclean specification can be manufactured for production rotors with properties that equal or exceed those for conventional 3.5NiCrMoV rotors in every detail. Of particular interest are the observations that the superclean steels appear to be virtually immune to temper embrittlement and may be used up to their creep limited temperature of 500°C (932°F). This paper reviews the mechanical properties of superclean 3.5 NiCrMoV steel: temper embrittlement susceptibility, uniformity of strength, impact properties, creep rupture properties, fatigue resistance, fracture toughness, and stress corrosion cracking suspectibility. [ABSTRACT FROM AUTHOR]

Cyclic deformation properties have been measured for high carbon steels that simulate the surface layers on carburized AISI 4027 steel. The influence of retained austenite is manifested in cyclic hardening and the development of mean compressive stresses. These responses, which are found to vary in direct proportion to the initial retained austenite content, are attributable to deformation-induced transformation. The importance of such cyclic changes is demonstrated by strain-life relations for carburized 4027; specimens with large amounts of retained austenite in the surface layers possess superior fatigue resistance to otherwise identical specimens that are more completely transformed. It is also shown that the benefits of retained austenite diminish as the intrinsic ductility of the fully transformed material increases. [ABSTRACT FROM AUTHOR]

Although cavitation erosion in hydraulic systems is an old problem, the damage mechanism that culminates in material loss was not known with certainty until recently. An investigation is described that aimed at clarifying the damage mechanism in cavitation erosion and applying that knowledge to make hydraulic equipment more resistant to cavitation. Strong correlations were established between cyclic deformation (fatigue) parameters and cavitation-erosion rates. This identification facilitated the search for more resistant materials. Finite element modeling confirmed that localized impacts on metal surfaces produce fatiguelike deformations and damage accumulation. Among available materials, near-equiatomic alloys of nickel and titanium are anomalously resistant to low-cycle fatigue and thus should be very resistant to cavitation erosion. Experiments confirmed the expected erosion resistance. Building large machines entirely out of NiTi is impractical, however, and a way of selectively cladding common constructional materials is required. Because NiTi has not been fusion welded successfully to other alloys, explosive bonding of thin NiTi plates to structural steel was investigated. Excellent welds were achieved, and the erosion resistance of the resulting clads has been demonstrated. Comparisons are made to other erosion processes and to other erosion-resistant materials, and some applications to hydraulic devices are suggested. [ABSTRACT FROM AUTHOR]

Biological structural materials, although composed of unremarkable substances synthesized at low temperatures, often exhibit superior mechanical properties. In particular, the quality in which nearly all biologically derived materials excel is toughness. The advantageous mechanical properties are attributable to the hierarchical, composite, structural arrangements common to biological systems. Materials scientists and engineers have increasingly recognized that biological designs or processing approaches applied to man-made materials (biomimesis) may offer improvements in performance over conventional designs and fabrication methods. In this survey, the structures and processing routes of marine shells, avian eggshells, wood, bone, and insect cuticle are briefly reviewed, and biomimesis research inspired by these materials is discussed. In addition, this paper describes and summarizes the applications of biomineralization, self-assembly, and templating with proteins to the fabrication of thin ceramic films and nanostructure devices. [ABSTRACT FROM AUTHOR]

We studied insulin processing and hepatic glycogenesis in cultured hepatocytes isolated from rat fetuses of 17, 19, and 21 days of gestation. Steady-state insulin binding increased by 250% between days 17 and 19, from 145±8 to 361±52 fmol/mg protein, and by an additional 40% (405±69 fmol/mg protein) by 21 days of gestation. At 37°C, I-insulin was rapidly (t<5 min) internalized by hepatocytes at all three ages, reaching maximal levels (63-76% of the total cell-associated radioactivity) by 15 min. I-labelled degradation products appeared rapidly (t<15 min) within the cells. Yet, the majority (68-77%) of the intracellular radioactivity consisted of intact I-insulin, even after 4 h at 37°C. Hepatocytes pre-loaded with I-insulin and then acid-stripped of surface-bound radioactivity, rapidly released both intact I-insulin (retroendocytosis) and its radiolabelled degradation products. While intact insulin was initially released more rapidly (t<6 min), and reached a plateau after 15-30 min, the degradation products continued to accumulate in the medium for at least 4 h. Methylamine inhibited intracellular I-insulin degradation at all three gestational ages and also blocked insulin-stimulated glycogenesis in 19- and 21-day hepatocytes, without altering basal glycogen synthesis. Insulin-stimulated glycogenesis was not induced in 17-day fetal rat hepatocytes in control or methylamine-treated cultures. We conclude that both degradative and retroendocytotic pathways for processing insulin are present in fetal rat hepatocytes by 17 days of gestation. Further, insulin-receptor processing was functionally related to the glycogenic action of insulin in responsive 19- and 21-day fetal rat hepatocytes [ABSTRACT FROM AUTHOR]

Permanent magnets are pervasive in modern industrial societies. They enable conversion of electrical energy to mechanical energy, they underlie microwave communications, and they constitute the active material in data-storage devices. To sustain the evolution of new and improved permanent-magnet materials, an active research enterprise is required. In this paper, the status of modern rare earth-transition metal magnets is outlined, contemporary research directions are summarized, and unresolved issues and research opportunities are enumerated. [ABSTRACT FROM AUTHOR]

Metallurgical understanding of order-disorder transitions is founded largely upon observations of alloys comprised of common metals and familiar (simple) crystal structures. Historically, the principal assumptions have been that only first and second nearest neighbor atoms in the crystal interact and therefore that the requisite atom movements necessary to effect transformation are small. These assumptions have been useful since they account, at least qualitatively, for the behavior of most 'classical' ordered alloys. Because of the increasing importance of unfamiliar substances in several technologies, we consider in this survey the degree to which the above concepts can be applied to less-familiar materials or crystal structures. Three types of systems are examined: 1) alloys of metallic elements, at least one constituent of which is in the less-common category; 2) interstitial ordering in dilute alloys; and 3) complex systems involving chalcogenides, oxides, and intercalation compounds. Primary emphasis is given to describing transitions and transformation mechanisms not encountered in common alloys, and to pointing out possible experimental advantages of metallurgically unfamiliar systems for studies of mechanisms and kinetics. [ABSTRACT FROM AUTHOR]

Martensite formation in ferrous alloys is inextricably connected with local deformation. In order to assess the role of this plastic work in the transformation, the dynamic responses of Fe−Ni−C austenites to imposed changes in deformation variables are investigated. For both stable and metastable compositions direct measurements are made of the separate and combined influences of prestrain and applied stress, and of strain-rate and dynamic strain aging. In addition, new martensite-start temperatures are defined and examined conceptually. A differential form of an energy balance that describes our viewpoint of austenite transformation at stress is then used to interpret the results. Some consequences concerning the importance of plastic work, its structure sensitivity, and the pervasive influence of local stress states are deduced and discussed. [ABSTRACT FROM AUTHOR]

A high purity Fe-C alloy of eutectoid composition has been transformed from homogenized austenite in two ways: isothermally and at forced constant-velocity. The latter transformation mode, forced over five decades of velocity, produces structures with characteristic dimensions ranging over nearly two orders of magnitude. There is a consistent alignment of the transformation product in the heat-flow direction at all velocities, but the classical pearlite morphology undergoes a microstructural transition at the higher velocities. A spacing-velocity relationship for regular lamellar pearlite was measured as Vλν = constant. [ABSTRACT FROM AUTHOR]