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n-Butene transformation was carried out at 350°C over medium pore size zeolites (H-FER, H-TON, H-EU-1 and H-MFI) and at 500°C over alumina. With fresh catalysts, not only isobutene but also propene and pentenes are primary products, which indicates that at least some of the butene isomerization occurs through oligomerization-isomerization-cracking steps (bimolecular mechanism). The large differences in selectivity are due to many factors, including whether or not trimer intermediates participate in the mechanism and limited product desorption. All the catalysts exhibit increasing isobutene selectivity with increasing time on-stream. This increase in selectivity can be explained by the selective isomerization of n-butene through a reaction process whose first step is the formation of trimethylpentene intermediates from isobutene product and n-butene reactant. This autocatalytic reaction can render the bimolecular transformation of n-butenes very selective to isobutene. La transformation du n-butène a été étudiée en réacteur dynamique à 350°C sur des zéolithes à taille de pore intermédiaire (H-FER, H-TON, H-EU-1 et H-MFI) et à 500°C sur alumine. Sur les catalyseurs frais, l'isobutène mais aussi le propène et les pentènes sont directement formés (produits primaires), ce qui démontre que l'isomérisation de squelette du n-butène se produit au moins en partie par des étapes successives d'oligomérisation, isomérisation et craquage (mécanisme bimoléculaire). Les différences importantes de sélectivité entre les catalyseurs sont dues à de nombreux facteurs : participation ou non d'intermédiaires trimères, limitations dans la désorption des produits branchés, etc. Sur tous les catalyseurs, la sélectivité en isobutène augmente avec le temps de travail. Cette augmentation s'explique par un nouveau mode d'isomérisation très sélectif impliquant comme intermédiaires des triméthylpentènes formés par réaction du n-butène sur des molécules d'isobutène retenues dans les pores de la ferrierite. Cette réaction autocatalytique rend très sélective en isobutène la transformation bimoléculaire du n-butène.

L'isomérisation des alcanes connaît un nouvel intérêt, depuis que la législation a prévu, par souci de protection de l'environnement, la suppression des alkyls de plomb dans les essences à l'horizon 1992. Cette réaction catalytique permet, en partant de n-paraffines de faible indice d'octane, issues du réformage catalytique ou de la distillation directe, d'obtenir des iso-paraffines présentant un indice d'octane beaucoup plus élevé. Elle est thermodynamiquement favorisée à basse température et nécessite par conséquent l'utilisation de catalyseurs développant une acidité importante. Deux types de catalyseurs sont actuellement utilisés industriellement : les catalyseurs à base de Pt sur lumine chlorée et les catalyseurs zéolithiques à base de Pt sur mordinite. Ces derniers sont considérés comme étant la nouvelle génération de catalyseurs. Ils présentent l'avantage d'être faciles à mettre en oeuvre et d'être beaucoup moins sensibles à la présence de poisons tels que soufre et eau dans la charge. Cependant ils conduisent à un gain d'octane considérablement plus faible que celui obtenu avec les catalyseurs Pt sur alumine chlorée. Cette étude bibliographique fait le point sur les différents mécanismes invoqués suivant le type de catalyseurs, les données cinétiques obtenues dans la littérature, et les différents procédés mis en oeuvre. Elle permet en particulier de mettre en évidence les contributions respectives des fonctions acides et métalliques pour l'isomérisation des alcanes de C4 à C7. En effet, il apparaît que suivant le type de catalyseurs utilisés, le mécanisme de la traction peut être bifonctionnel ou monofonctionnel acide. Dans certains cas, il pourrait même y avoir superposition des 2 mécanismes. L'étude de la longueur de la chaîne carbonée sur la réaction d'isomérisation ainsi que l'influence de la présence de composés cycliques, aromatiques ou non, ont également été envisagées. Il apparaît que la réactivité des alcanes augmente avec le nombre d'atomes de carbone et le degré de ramification de la molécule, et que la présence de composés aromatiques provoque une inhibition de la réaction d'isomérisation. Ce dernier point est très important pour l'industrie. There has been renewed interest in the isomerization of alkanes since legislation, with a view to environmental protection, has undertaken to eliminate lead alkyls from gasoline between now and 1992. Starting from low octane-number n-paraffins issuing from catalytic reforming or straight-run distillation, this catalytic reaction can be used to produce iso-paraffins having a much higher octane number. It is thermodynamically enhanced at low temperature and hence requires the use of catalysts developing high acidity. Two types of catalysts are currently used industrially, i. e. Pt base catalysts on chlorinated alumina and Pt base zeolitic catalysts on mordenite. These latter are considered to be the new generation of catalysts. They have the advantage of being easy to use and of being much less sensitive to the presence of poisons such as sulfur and water in the feedstock. However, they lead to a considerably lower improvement in octane than what is obtained with Pt catalysts on chlorinated alumina. This bibliographic study reviews the different mechanisms used according to the type of catalyst, the kinetic data obtained from the literature and the different processes used. In particular, it highlights the respective contributions of the acidic and metallic functions for the isomerization of C4 to C7 alkanes. Indeed, depending on the type of catalyst used, it appears the traction mechanism may be acidic bifunctional or monofunctional. In some cases two mechanisms might even be superposed. The study has also considered the effect of the length of this carbon chain on the isomerization reaction as well as the influence of the presence of ring compounds, whether aromatic or not. It seems that the reactivity of alkanes increases with the number of carbon atoms and with the degree of branching of the molecule, and that the presence of aromatic compounds inhibits the isomerization reaction. This last point is of great industrial importance.

Presents a study which investigated the application of the semiconducting phases of YBaCuO thin films as a bolometer for uncooled infrared detection. Structures of the buffer layers; Integration of the thin film in silicon micromachining technology; Resistance of thin films.

Objectives. Australian data regarding delirium in older hospitalized patients are limited. Hence, this study aimed to determine the prevalence and incidence of delirium among older patients admitted to Australian hospitals and assess associated outcomes. Method. A prospective observational study (n = 493) of patients aged ⩾70 years admitted to four Australian hospitals was undertaken. Trained research nurses completed comprehensive geriatric assessments using standardized instruments including the Confusion Assessment Method to assess for delirium. Nurses also visited the wards daily to assess for incident delirium and other adverse outcomes. Diagnoses of dementia and delirium were established through case reviews by independent physicians. Results. Overall, 9.7% of patients had delirium at admission and a further 7.6% developed delirium during the hospital stay. Dementia was the most important predictor of delirium at (OR = 3.18, 95% CI: 1.65-6.14) and during the admission (OR = 4.82; 95% CI: 2.19- 10.62). Deliriumat and during the admission predicted increased in-hospital mortality (OR = 5.19, 95% CI: 1.27-21.24;OR = 31.07, 95% CI: 9.30-103.78). Conclusion. These Australian data confirm that delirium is a common and serious condition among older hospital patients. Hospital clinicians should maintain a high index of suspicion for delirium in older patients. [ABSTRACT FROM AUTHOR]

Setting Hormone therapy used for the management of postmenopausal symptoms in older women appears to result in variable effects on cognitive function, depending on study design, subjects, tests used, and types of therapy. Objective To determine the effects of estrogen-only and estrogen plus progestogen preparations on cognitive performance (cognitive status, general and working memory) when taken ‘early’ and ‘late’ from the onset of menopause. Method The study consisted of 410 women who were participants in a longitudinal study, first recruited at age 40–80 years. They were tested for change over 5 years as an observational cohort by the Mini-Mental State Examination, National Adult Reading Test and the Wechsler Memory Scale Version 3. Cognitive decline, measured by age-adjusted scores, was defined as ≥10% negative change in each individual woman. Results Controlling for age and lifestyle factors, and using the criterion of decrease in score ≥10% over 5 years for ‘cognitive decline’, ‘early start’ of hormone therapy (<3 years from menopause) was strongly associated with reduction in risk by the Mini-Mental State Examination (estrogen-only preparation, p = 0.005) but with increase in risk for general memory (with estrogen plus progestogen preparation, p = 0.02). Overall, there were no major effects on subgroups with type/timing of hormone therapy in relation to testing for a negative change in cognitive function. Conclusion ‘Early start’ of estrogen-only hormone therapy was associated with reduced risk of global cognitive decline, and ‘early start’ estrogen-only and estrogen/progestogen hormone therapies showed increased risks of general memory decline. Even though this study did not have the power to discriminate between minor and mixed effects, it suggests that cognitive effects of hormone therapies may be mixed, depending on cognitive domain and timing of use/type of preparation. [ABSTRACT FROM AUTHOR]

The aim of this evaluation was to ascertain the perspectives of both carers of older people and residential care staff regarding the impact of a new radio program, Silver Memories, on the behavior and well-being of older listeners, as well as their opinions regarding the program's quality and appeal. Silver Memories is a unique radio service designed for the older listener that broadcasts music and programs from the 1920s to the 1950s. The program first aired in Brisbane, Australia, in April 2008. Nine carers of older people and 15 care staff from 11 residential aged care facilities in which Silver Memories had been introduced for a 3-month trial period were interviewed to obtain their views regarding the quality of the program and its impact on older listeners. The majority of respondents thought that listening to Silver Memories positively influenced the well-being, morale, and behavior of older listeners very much or greatly. Relaxation was the most frequently reported benefit and older listeners with dementia appeared to receive the greatest benefit. The friendliness and quality of the program were also rated highly. It was concluded that old-time music and programs such as those broadcast by Silver Memories appear to be beneficial for older people. [ABSTRACT FROM AUTHOR]

Objective To investigate the sexual behavior, sexual relationships, sexual satisfaction, sexual dysfunction and sexual distress in a population of older urban Australian women. Method In 2004, 474 women participating in the Longitudinal Assessment of Ageing in Women (LAW) Study completed a series of questionnaires about sexuality. They included the Short Personal Experiences Questionnaire (SPEQ), Relationship Assessment Scale (RAS), Female Sexual Distress Scale (FSDS), questions concerning past sexual abuse based on the Sex in Australia Study, and questions comparing present and past sexual interest and activity. Results The percentage of women with partners ranged from 83.3% in the 40-49-year age group to 46.4% women in the 70-79-year age group. The sexual ability of partners diminished markedly with age, with only 4.8% of the partners using medication to enable erections. Only 2.5% of women reported low relationship satisfaction. The incidence of sexual distress was also low, being reported by only 5.7% of women. Younger women and women with partners had higher levels of distress than older women. Indifference to sexual frequency rose from 26.7% in women aged 40-49 years to 72.3% in the 70-79-year age group. Past sexual abuse was recalled by 22.7% of women and 11.6% recalled multiple episodes of abuse. Women who recalled abuse had lower scores for satisfaction with sexual frequency. Conclusions It appears from this study that there is a wide range of sexual experience amongst aging women, from never having had a sexual partner, to having solitary sex, to having a relationship with or without sex into the seventh decade. As women age, they experience a decrease in sexual activity, interest in sex, and distress about sex. This may be associated with the loss of intimate relationships as part of separation, divorce or bereavement. Decreased sexual activity with aging may be interpreted as a biological phenomenon (part of the aging process) or as sexual dysfunction, or it may be the result of adapting to changed circumstances. [ABSTRACT FROM AUTHOR]

This paper presents the findings of a nationwide investigation into the mental well-being and job satisfaction of minority ethnic teachers in the UK. Data were collected via a questionnaire containing both open and closed questions. The sample, totalling 208 participants was derived from the National Union of Teachers (NUT) database of minority ethnic teachers and an advertisement in the NUT's Teacher magazine. Univariate analysis of the results revealed that this group of teachers, as compared with other groups were experiencing poorer mental health and lower job satisfaction. Multivariate analysis revealed four reliable factors regarding the ‘sources of stress’ these minority ethnic teachers perceived they were experiencing. They are the ‘hierarchy and culture of the school’, workload’, ‘cultural barriers’, and the ‘lack of status and promotion’. Some minority ethnic teachers reported that ethnic discrimination on a daily basis or at least several times per week was a contributory factor in their experience of stress. Many of the teachers believed they worked within an institutionally racist environment. Multiple regression analysis discovered that ‘total stress’, ‘total self-esteem’, ‘working conditions job satisfaction’ and ‘total discrimination’ were the major predictors of mental ill-health in the minority ethnic teachers. Job dissatisfaction was predicted by ‘total discrimination’, ‘workload’, ‘total general health’, ‘resolution strategy’, and the ‘lack of status and promotion’. [ABSTRACT FROM AUTHOR]

Objectives The aim of this study was two-fold: to assess climacteric symptoms and provide normative data for the Greene Climacteric Scale during the menopause transition, and to investigate the prevalence of climacteric symptoms in a representative sample of postmenopausal Australian women. Method A cohort of 500 premenopausal, perimenopausal and postmenopausal women aged 40–80 years participated in the Longitudinal Study of Ageing in Women (LAW study) at the Royal Brisbane and Women's Hospital, Brisbane, Australia. In year 1 of the study (2001), all participants completed the Greene Climacteric Scale and information regarding their menopausal status and the use of hormone therapy (HT) was obtained through a clinical interview with a qualified medical practitioner. Results The 50–59-year age group achieved the highest scores on the vasomotor and the depression scales in comparison to other age groups. Significant differences were also evident on the vasomotor and the depression scales on the basis of menopausal status, especially in perimenopausal women. Approximately 10% of women in the 60–79-year age group continued to experience vasomotor symptoms. Conclusion Vasomotor symptoms, as assessed by the Greene Climacteric Scale, are common during the menopause transition and remain elevated for some years in a minority of older postmenopausal women. The norms presented in this study are appropriate for use in an Australian population. [ABSTRACT FROM AUTHOR]

Prepares perovskite-type samarium and iron ceramic powders. Investigation of the structure of the products from thermal decomposition; Powders prepared by both methods used to deposit thick films onto alumina substrates.