Formation of amorphous anodic oxide films of controlled composition on aluminium alloys

Binary, non-equilibrium Al-29at%Nb, Al-44at%Ta, Al-19at%Ti, Al-25at%Ti and Al-32at%Zr alloys were prepared by magnetron sputtering and subsequently anodized at high Faradaic efficiency to grow barrier-type anodic films. Examination in the transmission electron microscope revealed amorphous anodic films of relatively uniform compositions across the film thicknesses, except for a layer of relatively pure alumina, of about 5% of the film thickness, present at the film/electrolyte interface of the Al-Ta alloy. The film compositions, from Rutherford backscattering spectroscopy, indicate that the alloy constituents are oxidized in their alloy proportions to form films comprising intimately mixed units of the various oxides, namely alumina, niobia, titania, tantala and zirconia. The films grow by co-operative transport of metal and oxygen ions under the electric field with formation of film material by both migration of metal ions outwards and of oxygen, and possibly hydroxyl, ions inwards. The average migration rates of Al³⁺, Nb⁵⁺, Ti⁴⁺ and Zr⁴⁺ ions are similar, to within 10%, but Ta⁵⁺ ions migrate more slowly than Al³⁺ ions. The results of the study show that a wide range of compositions of amorphous oxide films can be readily formed by anodic oxidation of appropriate alloys, including compositions containing units of normally crystalline anodic oxides, namely TiO₂ and ZrO₂.     

Predicting stability and change in frequency of intoxication from the college years to beyond: Individual-difference and role transition variables.

The authors examined whether individual-difference variables (e.g., family history of alcoholism, sex, personality traits, positive alcohol expectancies) and role transition-related variables (full-time work status, marital status, parenthood) moderate the "maturing-out" process whereby young adults who drink heavily during college decrease their drinking in the following years. Analyses were based on 288 young adults, assessed as full-time students (mostly college seniors, Year 4 of a larger study) and 3 years later (Year 7) when all had earned bachelor's degrees, and the analyses showed that frequency of intoxication (per week) decreased significantly (p?     

The meaning and management of neuroleptic medication: a study of patients with a diagnosis of schizophrenia

The meaning of medication and the way in which people use medicines has been the focus of a number of studies in recent years. However, there has been little attention directed to the meaning and management of neuroleptic medication by people who have received a diagnosis of schizophrenia. This topic is highly relevant to policy because of the central role given to neuroleptics in contemporary mental health and community care services. Using data from in-depth interviews with people with a diagnosis of schizophrenia we explore patients reasons for taking neuroleptics and the ways in which patients self-regulate their medication. The data suggest that the main utility of taking neuroleptic medication is to control specific symptoms and to gain personal control over managing symptoms. The costs of taking medication were side-effects which at times equalised or outweighed the positive gains of the neuroleptic medication. Patient accounts suggest that everyday medication practices are to a significant degree related to a policy context which stresses the need to survey and control the behaviour of people living in the community and the wider meaning and symbolic significance that schizophrenia has for patients in their everyday lives. For this reason, self regulatory action in this group of patients tends to be less evident and the threat of external social control greater than patients taking medication for other chronic conditions. The findings suggest the need to develop a collaborative patient-centred model of medication management for patients diagnosed with schizophrenia.     

Soft systems and systems engineering: on the use of conceptual models in information system development

Abstract. Many recent studies have shown that computer-based systems continue to ‘fail’ at a number of different levels (Romtec, 1988; KPMG, 1990) and it is increasingly apparent (Maclaren et al., 1991) that the most serious failures of information technology (IT) lie in the continuing inability to address those concerns which are central to the successful achievement of individual, organizational and social goals. It is the contention of this paper that this failing is precisely because these are the areas which are ignored or inadequately treated by conventional system development methods. There is, of course, a vast body of literature concerned with the understanding of complex human activity systems. This literature often reflects a mass of contradictions at the epistemological and the ontological level about the behaviour of such systems and has also spawned numerous methods (and methodologies) which seek to guide the individual in making successful interventions into organizational situations (Rosenhead, 1989). Despite this multiplicity of viewpoints many writers have posited a dichotomy between so-called 'soft and ‘hard’ approaches to problem situations and use this dichotomy to inform the choice of an appropriate problem-solving methodology (Checkland, 1985). In this paper we characterize these two approaches as being concerned with either the purpose(s) of the human activity system (i.e. ‘doing the right thing’) or with the design of the efficient means of achieving such purpose(s) (i.e. ‘doing the thing right’). It is our belief that much of the literature and work in either area has not concerned itself with the issues of the other. Writers on ‘hard’ engineering methods often assume the question of purpose to be either straightforward (e.g. given in the project brief) or, paradoxically, too difficult (e.g. it is not our concern as mere systems analysts). Writers on ‘soft’ methods on the other hand rarely have anything to say about the design and implementation of well-engineered computer-based systems, giving the impression that this is a somewhat mundane activity better left to technical experts. This paper, therefore, attempts to set out a rationale for the bringing together of principles from both ‘hard’ engineering and ‘soft’ inquiry methods without doing epistemological damage to either. To illustrate our argument we concentrate on JSD (Jackson system development) as an example of system engineering (Cameron, 1983) and SSM (soft systems methodology) as an example of system inquiry (Checkland, 1981; Checkland & Scholes, 1990). Our general thesis, however, does not depend upon either of these two approaches per se but applies to the overall issue of bringing together insights from two apparently opposed epistemological positions in an effort better to harness the power of IT in pursuit of purposeful human activity.     

In vitro assessment of the biological activity of basic fibroblast growth factor released from various polymers and biomatrices

The kinetics of controlled release of basic fibroblast growth factor (bFGF) from polymers (sutures, polycarbonate, Hydron, and Elvax), biopolymers (alginate), and biomatrices (lens capsules), and conditions for storage of bFGF (temperature, plastic type, heparin) were evaluated in vitro. Tissue culture proliferation bioassays with 3T3 fibroblasts, showed that only lens capsules with bFGF had a sustained release of bFGF for up to three weeks. The other materials released all of the 'bound' bFGF with two hours or produced an inflammatory response in vivo. Therefore, the lens tissue had the most potential for controlled long-term delivery of bFGF in vivo. These studies emphasise the importance of in vitro analysis of release kinetics of growth factors from a range of materials as a basis for potential in vivo applications.     

Randomised double blind trial of morphine versus diamorphine for sedation of preterm neonates

AIMS: To compare the safety and effectiveness of morphine and diamorphine for the sedation of ventilated preterm neonates in a double blind, randomised trial. METHODS: Eighty eight babies were allocated to receive either morphine (n = 44) or diamorphine (n = 44) by bolus infusion (200 or 120 mcg/kg, respectively, over two hours), followed by maintenance infusion (25 or 15 mcg/kg/h, respectively) during the initial phase of their respiratory disease. Serial monitoring of physiological, behavioural, and biochemical variables over the first 24 hours of the infusions was performed. Longer term outcomes were also monitored. RESULTS: Morphine, but not diamorphine, was associated with a mean (SEM) decrease in mean arterial blood pressure of 2.2 (1.0) mm Hg (p = 0.05) over the initial loading infusion. Physiological (blood pressure variability) and behavioural measures of sedation (clinical assessment and sedation scoring) indicated that the two drug regimens were equally effective after 24 hours, but the sedative effects of diamorphine were evident more quickly than those of morphine. Both regimens significantly reduced plasma adrenaline concentrations over the first 24 hours of the infusions. No significant differences in mortality, ventilator days, chronic lung disease or intracranial lesions were noted. CONCLUSIONS: Both drug regimens reduce the stress response to ventilation in preterm neonates. However, diamorphine's more rapid onset of sedation and morphine's hypotensive tendency suggest that diamorphine is preferable for the sedation of mechanically ventilated preterm neonates.