467 research outputs found
Computer model to predict electron beam-physical vapour deposition (EB-PVD) and thermal barrier coating (TBC) deposition on substrates with complex geometry
For many decades gas turbine engineers have investigated methods to improve engine
efficiency further. These methods include advances in the composition and processing
of materials, intricate cooling techniques, and the use of protective coatings. Thermal
barrier coatings (TBCs) are the most promising development in superalloy coatings
research in recent years with the potential to reduce metal surface temperature, or
increase turbine entry temperature, by 70-200°C.
In order for TBCs to be exploited to their full potential, they need to be applied to the
most demanding of stationary and rotating components, such as first stage blades and
vanes. Comprehensive reviews of coating processes indicate that this can only be
achieved on rotating components by depositing a strain-tolerant layer applied by the
electron beam-physical vapour deposition (EB-PVD) coating process.
A computer program has been developed in Visual c++ based on the Knudsen cosine
law and aimed at calculating the coating thickness distribution around any component,
but typically turbine blades. This should permit the controlled deposition to tailor the
TBC performance and durability. Various evaporation characteristics have been
accommodated by developing a generalised point source evaporation model that
involves real and virtual sources.
Substrates with complex geometry can be modelled by generating an STL file from a
CAD package with the geometric information of the component, which may include
shadow-masks. Visualisation of the coated thickness distributions around components
was achieved using OpenGL library functions within the computer model.
This study then proceeded to verify the computer model by first measuring the coating
thickness for experimental trial runs and then comparing the calculated coating
thickness to that measured using a laboratory coater. Predicted thickness distributions
are in good agreement even for the simplified evaporation model, but can be improved
further by increasing the complexity of the source model
The different shades of brand hate: A qualitative approach
While Brand Love has been extensively studied, Brand Hate is still in the early stages
of its theoretical development. Aiming to reduce that gap, this project has three main
goals: first, conduct a thorough literature review, seeking to consolidate what has been
written about the concepts of love, hate, brand love, brand hate and several supportive
elements such as emotions, consumer-brand relationships, brand and anti-brand
communities; second, perform and code multiple semi-structured/in-depth interviews,
analyse and discuss the Portuguese costumer’s perception on the topic and link it with
academia; third, build a literate crossing between Marketing and Linguistics that can
be used by future studies. Supporting these objectives is the Constructivist Grounded
Theory methodology. Among the findings generated by this process, seven facets were
uncovered: emotions are essential to the shopping experience; there is an occasional
contemporaneity between diverse elements of Active Brand Hate; Negative Past
Experiences was the most cited antecedent of Brand Hate; it is possible to turn Brand
Hate into neutral or positive relationships, but so is the inverse; Negative Double
Jeopardy should be divided into parcels; Oppositional Brand Loyalty ought be tested
as another antecedent; there are dissimilar types of Brand Hostages.info:eu-repo/semantics/publishedVersio
Fluorinated Molecules and Nanotechnology: Future 'Avengers' against the Alzheimer's Disease?
Alzheimer's disease (AD) is a serious health concern, affecting millions of people globally, which leads to cognitive impairment, dementia, and inevitable death. There is still no medically accepted treatment for AD. Developing therapeutic treatments for AD is an overwhelming challenge in the medicinal field, as the exact mechanics underlying its devastating symptoms is still not completely understood. Rather than the unknown mechanism of the disease, one of the limiting factors in developing new drugs for AD is the blood-brain barrier (BBB). A combination of nanotechnology with fluorinated molecules is proposed as a promising therapeutic treatment to meet the desired pharmacokinetic/physiochemical properties for crossing the BBB passage. This paper reviews the research conducted on fluorine-containing compounds and fluorinated nanoparticles (NPs) that have been designed and tested for the inhibition of amyloid-beta (A beta) peptide aggregation. Additionally, this study summarizes fluorinated molecules and NPs as promising agents and further future work is encouraged to be effective for the treatment of AD
The role of antimicrobial stress on Pseudomonas aeruginosa colony morphology diversity, tolerance and virulence
In natural environments, as well as in infections, bacteria faced several stresses like starvation, heat exposure, antimicrobials and host defense after entry in human body. The ability to quickly adapt to a new environment is critical to bacteria and the underlying mechanisms are not fully understood. One of the strategies adopted by bacteria is a high frequency of phenotype switching by a mechanism called phase variation. A sign of these bacterial changes is the altered colony morphology on solid media. Several colony morphologies have been isolated from clinical strains, being the best-studied the small colony variants, the rugose small colony variants and the mucoid phenotype.
It was aimed to study the prevalence and diversity of colony morphologies from planktonic and sessile P. aeruginosa (Pa) ATCC, chemically stressed, and to compare with the ones developed by a P. aeruginosa isolated from a medical device (Pa I). Pa is one of the most important opportunistic pathogen commonly found in clinical arena being often responsible for acute and chronic infections.
Planktonic and sessile Pa and Pa I were in vitro stressed by continuous exposure to benzalkonium chloride (BZK) and peroxide hydrogen and by attack with the same products. The stressed bacteria were collected, serial diluted and plated onto TSA to inspect colony morphology variants. Each predominant bacterial morphology was harvested and reserved for further phenotypic and motility characterization.
The results demonstrated that cells coming from biofilm and planktonic growth of Pa, regardless they were stressed or not or the type of stress implemented, develop colonies mostly with the same morphotype, type II, characterized by big and regular colony circumference, with small and dark center and wrinkled surface. This colony type showed to have a good ability to form biofilms, although the colonies from the stressed cultures developed biofilms with higher biomass accumulated.
The Pa I gave rise to high diversity of colony morphotypes, being 3 of them more prevalent and cataloged as type XVII, XXIII, XXVIII. The types XVII and XXVIII are characterized by regular colony circumferences with craters in the center. However their superficial area presented different colors. Type XXIII has irregular colony shape with craters in the center. These 3 morphotypes showed similar biofilm formation ability between them but lower than type II.
Nonetheless the phenotypic differences found between the several morphotypes, all of them generated biofilms with identical tolerance to antimicrobials (BZK and the fluoroquinolone antibiotic ciprofloxacin-CIP). However, the cells resulting from the planktonic growth of Pa I morphotypes demonstrated two-fold tolerance to BZK and CIP than their Pa counterparts.
Regarding bacteria motility, results highlighted that all Pa I morphotypes had impaired swimming motilities compared to type II. This result seems to indicate that the capacity of adhesion or invasion of Pa I morphotypes to, respectively, surfaces or tissues was compromised, which may interfere with their virulence. Although, the latter is not sustained by the susceptibility patterns, emphasizing the ambiguous relationship between virulence and antimicrobial resistance.
The morphologies described are not similar with previous reports and the colony morphologies more prevalent seemed to be less virulent than typical ones. Among the various colony morphologies detected, no Pa I morphotype match with Pa type. So, it can be concluded that phase variation is an adaptive strategy of bacteria to respond to fluctuating environment leading to mixed populations where the chances for survival is higher. The generation of varied bacterial phenotypes may be the sum of previous and successive adaptations suffer by Pa I as an attempt to adjust to adverse habitats.IBB-CEB and FCT, for the financial support (Project PTDC/SAUESA/64609/2006; PhD Grant SFRH/BD/31065/2006
Factors affecting the production of 4-ethylphenol by the yeast Dekkera bruxellensis in enological conditions
"Food Microbiology" article in PressThe conversion of p-coumaric acid into 4-ethylphenol was studied in Dekkera bruxellensis ISA 1791 under defined conditions in
synthetic media. The production of 4-ethylphenol occurred roughly between mid-exponential growth phase and the beginning of the
stationary phase. This behaviour was observed when glucose was the only energy and carbon source, the conversion rate being close
to 90%. Ethanol, as the single energy source, yielded conversion rates close to 80% while in the presence of trehalose and acetic acid
conversion rates lower than 10% were obtained. The production of 4-ethylphenol was not observed when the cells were maintained
in buffer solution without carbon and energy sources. The precursor of 4-ethylphenol, p-coumaric acid, was not utilized as energy
and carbon source. Furthermore, it was shown that 4-vinylphenol may be used as a precursor of 4-ethylphenol in the absence of pcoumaric
acid.
Growth and 4-ethylphenol production were inhibited by increasing concentrations of ethanol, being fully prevented at 13% (v/v)
ethanol.
The cultivation of strain ISA 1791 in mixed culture with Saccharomyces cerevisiae, in synthetic medium, showed that the cell
numbers of D. bruxellensis increased from 104 cfu/ml to 5 109 cfu/ml. Laboratory microvinifications of white and red juices
inoculated with as low as 10 cfu/ml of D. bruxellensis and 107 cells/ml of S. cerevisiae showed growth of D. bruxellensis to levels of
about 5 108 cfu/ml. In addition, 4-ethylphenol production by D. bruxellensis was observed only after complete fermentation of the grape juice
Cultivares melhoradas de feijĂŁo (Phaseolus vulgaris L.) avaliadas a nĂvel de propriedades agrĂcolas.
Como etapa inicial no processo de adocao de uma cultivar pelos agricultores, ha necessidade de que ela mantenha nas propriedades agricola o seu bom desempenho obtido nas estacoes experimentais. Visando a comprovar esse fato, varias cultivares foram avaliadas simultaneamente na estacao experimental do Centro Nacional de Pesquisa de Milho e Sorgo e em algumas propriedades do estado de Minas Gerais. Ao todo foram conduzidos 13 ensaios na safra "outubro-inverno", dos anos agricolas de 1988 e 1990 e na "seca" do ano de 1990. Constatou-se que as cultivares apresentaram diferencas em produtividade e que o comportamento dessas cultivares nao foi coincidente nos diferentes locais. Esse ultimo fato contribuiu para que a correlacao classificatoria de Spearman fosse de pequena magnitude. Isso evidencia que ha necessidade das cultivares serem avaliadas nas propriedades agricolas antes de sua recomendacao aos agricultores. Verificou-se, tambem, que algumas cultivares apresentaram, na media de todos os experimentos, produtividade superior a da cultivar Carioca, entre elas a 'Jalo', ESAL 506'. 'Rio Vermelho' e 'ESAL -512'
The Impact of the Semente Program on the Family-Focused Practice of Mental Health Professionals in Portugal.
Background: Children of parents with mental illness (COPMI) are a high-risk group. There is a strong association between parents' psychiatric disorders and the incidence of psychopathology in their children. These children need to be identified and supported by mental health workers early, and hence, clinical practice in adult mental health services needs to change from a focus on individual patients to a more systemic family focus. "Semente," a mental health promotion program developed by the Psychiatry Service of Fernando Fonseca hospital (Lisbon, Portugal), had been established to identify these children and families and promote their mental health, by decreasing the impact of risk factors and promoting protective factors. The program included preventive COPMI interventions and implementation of activities offered to families with children in the mental health care. The aim of the present study was to evaluate changes in mental health care after the training in "Child Talks" intervention (two to three psycho-educational meetings with parents and children) and implementation of the "Semente" program. Methods: Participants (N = 51) were all professionals from Psychiatric Service of Fernando Fonseca Hospital who received Child Talks training. The Family-Focused Mental Health Practice Questionnaire (FFMPQ) was used to measure change in professionals' attitudes, knowledge, confidence, and organizational structure in working with these families. All participants filled in the questionnaire before training and 10 months later. Results: The results showed that, from pre- to post-measurement, the professionals changed clinical practice significantly. The largest changes were visible in the improved provision of support at the workplace for family-focused practice and the clarity and availability of the policies and procedures. Furthermore, the skill and knowledge of the mental health workers showed significant improvement at posttest. Conclusion: The positive results of this study were not unexpected; the training, implementation of routines, and procedures as well as workplace support were aims of the "Semente" program. Interpretation of the results should be taken with caution because of the small sample and the lower reliability of some of scales of the FFMPQ. The results indicate that professionals moved from patient focus to family focus during the implementation of the "Semente" program.info:eu-repo/semantics/publishedVersio
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