751 resultados para Polyhydroxy alcohol
Resumo:
The entomopathogenic fungi Beauveria bassiana, Metarhizium anisopliae and Paecilomyces farinosus were cultured on solid agar media containing different carbohydrate components (glycerol, glucose, trehalose or starch) at concentrations of ≤ 142.7 g added carbon 1-1 for 30 d at 25°C. The water activity (a(w)) of the media ranged from 0.925 to 0.998. Growth of M. anisopliae and P. farinosus was stimulated between 0.975 and 0.995 a(w) on glucose media and that of P. farinosus at 0. 975 a(w) on glycerol media. At < 0.970 a(w), growth of each fungal species was significantly reduced (P < 0.05). Polyhydroxy alcohols (polyols) and trehalose were extracted from conidia produced on different media and quantified using HPLC. Total polyol content of conidia produced on glucose media varied between 5.2 and 52.2 mg g-1 for B. bassiana, 77.3 and 90.3 mg g-1 for M. anisopliae, and 26.7 and 76.1 mg g-1 for P. farinosus. The amounts of specific polyols in conidia varied significantly from media of different glucose concentrations. Mannitol was the predominant polyol in conidia of all three species, with conidia of M. anisopliae, for example, containing as much as 75.2 mg mannitol g-1 when cultured on glucose media. The amount of the lower molecular mass polyols glycerol and erythritol was greater in conidia produced on glucose media with > 50.0 g added carbon 1-1 than that in conidia produced at lower glucose concentrations. Conidia contained between 10.8 and 20.8 mg glycerol plus erythritol g-1 on glucose media with 142.7 g added carbon 1-1, depending on species. Conversely, conidia of B. bassiana and P. farinosus contained maximum amounts of trehalose ( ≤ 23.5 mg g-1) when produced on glucose media with < 50.0 g added carbon l-1, and trehalose content was considerably less at higher glucose concentrations. There were accumulations of glycerol and erythritol in conidia of all three species when grown on glycerol media with > 25.0 g added carbon 1-1; conidia of B. bassiana contained up to 154.0 mg glycerol plus erythritol g-1. hen B. bassiana and P. farinosus were grown on trehalose media, conidia contained up to 222.1 mg trehalose g-1. By contrast, conidia of M. anisopliae contained < 17.0 mg trehalose g-1 under all conditions tested. The water availability of solutions of different polyols is discussed in relation to their potential to act in osmotic adjustment during germination. The ability to manipulate polyol and trehalose content of fungal propagules may be critical in enhancing the storage life and efficacy of biological control agents.
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This feature article highlights work from the authors' laboratories on the various kinds of oxide optical materials, mainly luminescence and pigment materials with different forms (powder, core-shell structures, thin film and patterning) prepared by the Pechini-type sol-gel (PSG) process. The PSG process, which uses the common metal salts (nitrates, acetates, chlorides, etc.) as precursors and citric acid (CA) as chelating ligands of metal ions and polyhydroxy alcohol (such as ethylene glycol or poly ethylene glycol) as a cross-linking agent to form a polymeric resin on molecular level, reduces segregation of particular metal ions and ensures compositional homogeneity. This process can overcome most of the difficulties and disadvantages that frequently occur in the alkoxides based sol-gel process.
Resumo:
The well-known polymeric precursor route is a simple and low-cost sol-gel method based on the preparation of an aqueous precursor solution of metals followed by the addition of a water-soluble polymer. This method consists of a polyesterification process between a metal chelate complex by using a hydroxycarboxylic acid and a polyhydroxy alcohol. In this work, citric acid (CA), tartaric acid (TA) and ethylenediaminetetraacetic acid (EDTA) are used as the hydroxycarboxylic acid and ethylene glycol (EG) is used as the polyhydroxy alcohol. The effects of the precursor pH solution, time and temperature of polymerization step as well as the combination of different chelating agents in order to obtain nanoscopic YBa2Cu3Oy samples were traced. (c) 2007 Elsevier B.V. All rights reserved.
Resumo:
Several routes and procedures have been used in these last years as an effort to achieve single-phase mesoscopic-size superconducting samples. In this paper, the effects of using citric acid (CA), tartaric acid (TA) and ethylenediaminetetraacetic acid (EDTA) as chelating agents and ethylene-glycol (EG) as polyhydroxy alcohol were studied in order to establish conditions to avoid the occurrence of BaCO(3) undesirable secondary phase in YBa(2)Cu(3)O(7-delta) (YBCO). Thermal evolution of intermediate compounds formed during the calcinations process by the use of different chelating agents was traced using thermogravimetric and spectroscopic methods. The obtained results indicated that the polymer breakdown of samples prepared using EDTA occurs at higher temperatures than others chelating agents and also reduces the occurrence of BaCO(3) secondary phase as studied by X-ray diffraction measurements. Furthermore, the magnetic response of the mesoscopic-size YBCO specimens obtained was verified showing that samples present different superconducting response.
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Typically adolescents' friends are considered a risk factor for adolescent engagement in risk-taking. This study took a more novel approach, by examining adolescent friendship as a protective factor. In particular it investigated friends' potential to intervene to reduce risk-taking. 540 adolescents (mean age 13.47 years) were asked about their intention to intervene to reduce friends' alcohol, drug and alcohol-related harms and about psychosocial factors potentially associated with intervening. More than half indicated that they would intervene in friends' alcohol, drug use, alcohol-related harms and interpersonal violence. Intervening was associated with being female, having friends engage in overall less risk-taking and having greater school connectedness. The findings provide an important understanding of increasing adolescent protective behavior as a potential strategy to reduce alcohol and drug related harms.
Resumo:
Objectives. We tested predictions from the elaborated intrusion (EI) theory of desire, which distinguishes intrusive thoughts and elaborations, and emphasizes the importance of imagery. Secondarily, we undertook preliminary evaluations of the Alcohol Craving Experience (ACE) questionnaire, a new measure based on EI Theory. Methods. Participants (N ¼ 232) were in correspondence-based treatment trials for alcohol abuse or dependence. The study used retrospective reports obtained early in treatment using the ACE, and daily self-monitoring of urges, craving, mood and alcohol consumption. Results. The ACE displayed high internal consistency and test – retest reliability and sound relationships with self-monitored craving, and was related to Baseline alcohol dependence, but not to consumption. Imagery during craving was experienced by 81%,with 2.3 senses involved on average. More frequent imagery was associated with longer episode durations and stronger craving. Transient intrusive thoughts were reported by 87% of respondents, and were more common if they frequently attempted to stop alcohol cognitions. Associations between average daily craving and weekly consumption were seen. Depression and negative mood were associated with more frequent, stronger and longer lasting desires for alcohol. Conclusions. Results supported the distinction of automatic and controlled processes in craving, together with the importance of craving imagery. They were also consistent with prediction of consumption from cross-situational averages of craving, and with positive associations between craving and negative mood. However, this study’s retrospective reporting and correlational design require that its results be interpreted cautiously. Research using ecological momentary measures and laboratory manipulations is needed before confident inferences about causality can be made.
Resumo:
Depression and alcohol use disorders frequently co-occur and are highly prevalent. Both conditions are known to impair cognitive functioning, yet research into the role of these impairments in response to Cognitive Behaviour Therapy (CBT) is limited. The purpose of the present study was to examine the relationship between baseline neuropsychological performance, severity of depressive symptoms and alcohol use disorders. Participants with current depression and hazardous alcohol use were functioning in the average range on all neuropsychological measures prior to treatment entry. Baseline measures of drinking severity and a range of cognitive functions were inversely correlated. After controlling for other baseline variables, superior baseline cognitive functioning predicted greater reductions in depression severity after 17 weeks. These predictive effects occurred across both brief and extended interventions. Findings suggest that improvement in depression following psychological treatment is enhanced by greater fluid reasoning ability and is predicted by executive functioning, regardless of the treatment length or problem focus.
Resumo:
Introduction and Aims: Remote delivery of interventions is needed to address large numbers of people with alcohol use disorders who are spread over large areas. Previous correspondence trials typically examined its effects as stand-alone treatment. This study aimed to test whether adding postal treatment to general practitioner (GP) support would lower alcohol use more than GP intervention alone. Design and Methods: A single-blind, randomised controlled trial with a crossover design was conducted over 12 months on 204 people with alcohol use disorders. Participants in an immediate correspondence condition received treatment over the first 3 months; those receiving delayed treatment received it in months 3–6. Results: Few participants were referred from GPs, and little intervention was offered by them. At 3 months, 78% of participants remained in the study. Those in immediate treatment showed greater reductions in alcohol per week, drinking days, anxiety, depression and distress than those in the delayed condition. However, post-treatment and follow-up outcomes still showed elevated alcohol use, depression, anxiety and distress. Greater baseline anxiety predicted better alcohol outcomes, although more mental distress at baseline predicted dropout. Discussion and Conclusions: The study gave consistent results with those from previous research on correspondence treatments, and showed that high levels of participant engagement over 3 months can be obtained. Substantial reductions in alcohol use are seen, with indications that they are well maintained. However, many participants continue to show high-risk alcohol use and psychological distress.
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Background: Blood for transfusion may become contaminated at any point between collection and transfusion and may result in bacteraemia (the presence of bacteria in the blood),severe illness or even death for the blood recipient. Donor arm skin is one potential source of blood contamination, so it is usual to cleanse the skin with an antiseptic before blood donation. One-step and two-step alcohol based antiseptic regimens are both commonly advocated but there is uncertainty as to which is most effective.----- Objectives: To assess the effects of cleansing the skin of blood donors with alcohol in a one-step compared with alcohol in a two-step procedure to prevent contamination of collected blood or bacteraemia in the recipient.----- Search strategy: We searched the Cochrane Wounds Group Specialised Register (March 10 2009); The Cochrane Central Register of Controlled Trials(CENTRAL) The Cochrane Library 2009, Issue 1; Ovid MEDLINE - (1950 to February Week 4 2009); Ovid EMBASE - (1980 to 2009 Week 9); and EBSCO CINAHL - (1982 to February Week 4 2009). We also searched the reference lists of key papers.----- Selection criteria: All randomised trials (RCTs) comparing alcohol based donor skin cleansing in a one-step versus a two-step process that includes alcohol and any other antiseptic for pre-venepuncture skin cleansing were considered. Quasi randomised trials were to have been considered in the absence of RCTs.----- Data collection and analysis: Two review authors independently assessed studies for inclusion.----- Main results: No studies (RCTs or quasi RCTs) met the inclusion criteria. Authors’ conclusions We did not identify any eligible studies for inclusion in this review. It is therefore unclear whether a two-step, alcohol followed by antiseptic skin cleansing process prior to blood donation confers any reduction in the risk of blood contamination or bacteraemia in blood recipients, or conversely whether a one-step process increases risk above that associated with a two-step process.
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There is no specific self-efficacy measure that has been developed primarily for problem drinkers seeking a moderation drinking goal. In this article, we report the factor structure of a 20-item Controlled Drinking Self-Efficacy Scale (CDSES; Sitharthan et al., 1996; Sitharthan et al., 1997). The results indicate that the CDSES is highly reliable, and the factor analysis using the full sample identified four factors: negative affect, positive mood/social context, frequency of drinking, and consumption quantity. A similar factor structure was obtained for the subsample of men. In contrast, only three factors emerged in the analysis of data on female participants. Compared to women, men had low self-efficacy to control their drinking in situations relating to positive mood/social context, and subjects with high alcohol dependence had low self-efficacy for situations relating to negative affect, social situations, and drinking less frequently. The CDSES can be a useful measure in treatment programs providing a moderation drinking goal.
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Anecdotal evidence highlights issues of alcohol and other drugs (AODs) and its association with safety risk on construction sites. Information is limited however regarding the prevalence of AODs in the workplace and there is limited evidential guidance regarding how to effectively address it. This research aimed to scientifically evaluate the use of AODs within the Australian construction industry in order to reduce the potential resulting safety and performance impacts and engender a cultural change in the workforce. A national qualitative and quantitative evaluation of the use of AODs was conducted with approximately 500 employees. Results indicate that as in the general population, a proportion of those sampled in the construction sector may be at risk of hazardous alcohol consumption and support the need for evidence-based, tailored responses. This is the first known study to scientifically evaluate the use of AODs and potential workplace safety impacts in the construction sector.
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Event-specific scales commonly have greater power than generalized scales in prediction of specific disorders and in testing mediator models for predicting such disorders. Therefore, in a preliminary study, a 6-item Alcohol Helplessness Scale was constructed and found to be reliable for a sample of 98 problem drinkers. Hierarchical multiple regression and its derivative path analysis were used to test whether helplessness and self-efficacy moderate or mediate the link between alcohol dependence and depression, A test of a moderation model was not supported, whereas a test of a mediation model was supported. Helplessness and self-efficacy both significantly and independently mediated between alcohol dependence and depression. Nevertheless, a significant direct effect of alcohol dependence on depression also remained.