3,925 research outputs found
Diversity in Retirement Wealth Accumulation
Examines household wealth by source, such as Social Security, home equity, savings, and defined benefit pensions; how their savings build up with age; and how total wealth accumulations vary by income, education, and race/ethnicity. Explores implications
Online Thermal Analysis of Batch Roasted Coffee Beans
We constructed and instrumented a fluidised-bed coffee roaster. This work has been carried out as part of a search for the “ideal point”, which is the point in time when an expert roaster would terminate the roast in order to yield beans that produce the optimal brew. We roasted Costa Rican Arabica beans whilst controlling the roasting temperature to follow a linear ramp. We measured and recorded the input, output, and coffee bean surface temperatures. We introduce the idea of “bean load”, an uncalibrated measure of the heat load presented by the material being roasted. The bean load under constantly-ramping bean surface temperature shows the roast is increasingly endothermic. Toward the end of the roast the endothermic phenomena decrease, or are assisted by exothermic activity. The bean load also has a repeatable dip around first crack. Due to limitations with the roaster we were not able to make reliable measurements at and beyond second crack. We observed no waypoints or events that might be used to pinpoint the “ideal point” to end the roast
Determinants of farmer adoption of organic production methods in the fresh-market produce sector in California: A logistic regression analysis
This research uses binomial and multinomial logistic regression models to identify the factors that influence farmers adoption of organic technology. Using a sample of 175 farmers growing fresh-market produce in three California counties, the first model examines farmers choice between conventional-only and organic-only production. The second model compares conventional-only and "dual-method" (combined conventional and organic) production, while the third model employs all three choices in a multinomial model. These results, which indicate that gross sales, direct marketing, number of crops and acres, farmer age, and computer usage are significant determinants, have implications on policies that regulate the organic foods sector.Production Economics,
Mobility and safety issues in drivers with dementia
ABSTRACTAlthough automobiles remain the mobility method of choice for older adults, late-life cognitive impairment and progressive dementia will eventually impair the ability to meet transport needs of many. There is, however, no commonly utilized method of assessing dementia severity in relation to driving, no consensus on the specific types of assessments that should be applied to older drivers with cognitive impairment, and no gold standard for determining driving fitness or approaching loss of mobility and subsequent counseling. Yet, clinicians are often called upon by patients, their families, health professionals, and driver licensing authorities to assess their patients’ fitness-to-drive and to make recommendations about driving privileges. We summarize the literature on dementia and driving, discuss evidenced-based assessments of fitness-to-drive, and outline the important ethical and legal concerns. We address the role of physician assessment, referral to neuropsychology, functional screens, dementia severity tools, driving evaluation clinics, and driver licensing authority referrals that may assist clinicians with an evaluation. Finally, we discuss mobility counseling (e.g. exploration of transportation alternatives) since health professionals need to address this important issue for older adults who lose the ability to drive. The application of a comprehensive, interdisciplinary approach to the older driver with cognitive impairment will have the best opportunity to enhance our patients’ social connectedness and quality of life, while meeting their psychological and medical needs and maintaining personal and public safety.</jats:p
Involvement of integrins in the adhesion of osteoblastic cells to a type-I collagen matrix
Se han desarrollado varios biomateriales con potencial aplicaci ón en la reconstrucción de tejidos. En este sentido, existe un creciente interés en el diseño de materiales de implante óseo con máxima biocompatibilidad y adecuada adhesividad celular. El objetivo de este trabajo fue estudiar cuáles receptores integrinas participan en la adhesión de osteoblastos a una matriz de colágeno tipo-I. Se analizaron dos líneas celulares osteoblásticas: UMR106, derivada de osteosarcoma de rata; y MC3T3E1, derivada de calvaria de rata. Las células se cultivaron durante una hora sobre plástico, o sobre un gel de colágeno tipo-I, solas o co-incubadas con diferentes péptidos: (a) péptido-b, un oligopéptido de 13 aminoácidos que corresponde a la secuencia conservada 113-125 de la subunidad b de los receptores integrinas; (b) RGD (Arg-Gly-Asp), que corresponde a la secuencia de reconocimiento de la subunidad a de las integrinas a1,5b1; o (c) DGEA (Asp-Gly-Glu-Ala), la secuencia de reconocimiento de la subunidad a de las integrinas a2b1. La adhesión y la inducción de extensiones celulares se evaluaron microscópicamente luego de lavar, fijar y colorear las células con Giemsa. Los resultados demostraron que las células osteoblásticas se adhieren más fácilmente a un sustrato de colágeno tipo-I que al plástico (86 ± 5 células/campo vs. 69 ± 4 células/campo para colágeno tipo-I vs. plástico, respectivamente, p &lt; 0,02). El péptido-b inhibió la adhesión de ambas líneas celulares a una matriz de colágeno y el efecto inhibidor mostró dependencia dosis-respuesta. Por otro lado, este péptido indujo en las células tipo osteoblastos UMR106 un aumento del agrupamiento intercelular, y una reducción en la inducción de extensiones celulares. Estos cambios morfol ógicos podrían estar indicando un incremento en las interacciones célulac élula y una disminución en las interacciones célula-matriz, posiblemente inducidos por el péptido-b. De forma similar, los péptidos RGD y DGEA disminuyeron significativamente, entre un 20 y 30 %, la adhesión de las células UMR106 y MC3T3E1 a la matriz de colágeno. Las células UMR106 cultivadas sobre colágeno en presencia de DGEA mostraron un mayor estiramiento citoplasmático, con inducción de extensiones celulares en múltiples direcciones. En suma, estos resultados sugieren que las subunidades a y b de varios receptores integrinas están involucradas en la adhesión de las células tipo osteoblastos a una matriz de colágeno tipo-I. Así, el recubrimiento de ciertos biomateriales con péptidos de reconocimiento o con mol éculas de colágeno intacto, podría mejorar la osteointegración de implantes para la reparación del tejido óseo.Several biomaterials have been developed with applications in bone tissue engineering. In this context, there is a growing interest in developing bone implant materials with improved biocompatibility and cell adhesion properties. The aim of this study was to research which integrin receptors participate in the attachment of osteoblastic-like cells to a type- I collagen matrix. Two osteoblast-like cells, the UMR106 rat osteosarcoma cell line and the MC3T3E1 mouse calvaria- derived cells, were analyzed.
Cells were plated for one hour either on plastic or a type-I collagen film, alone or co-incubated with different peptides: (a) b-Peptide, a 13-aminoacid oligopeptide corresponding to preserved sequence 113-125 of the b-subunit of integrin receptors; (b) RGD (Arg-Gly-Asp), which corresponds to the a-subunit recognition sequence of a1,5b1 integrins; or (c) DGEA (Asp-Gly- Glu-Ala), the a-subunit recognition sequence of a2b1 integrins. Cell adhesion and spreading were evaluated microscopically after fixing and staining the cells with Giemsa. The results showed that osteoblast-like cells adhere more easily to a type-I collagen substratum than to plastic (86 ± 5 cells/ field vs. 69 ± 4 cells/field for type-I collagen vs. plastic, respectively, p &lt; 0.02).
The b-peptide inhibited the adhesion of both cell lines to the collagen matrix in dose-dependent way. Addition-ally, this peptide induced an increase in UMR106 cells clumping and a decrease in cells spreading. These morphological features would suggest an increase in cell-cell interactions and a decrease in cell-matrix interactions, possibly mediated by b-peptide. The RGD and DGEA peptides significantly decreased UMR106 and MC3T3E1 adhesion to the collagen matrix (ranging from 20 to 30 % inhibition). On the other hand, UMR106 cells grown on collagen in the presence of DGEA exhibited greater spreading with cellular extensions in multiple directions.
Altogether, the obtained results suggest that both a and b subunits of several integrin receptors are involved in the attachment of osteoblast-like cells to a type-I collagen matrix. The coating of different biomaterials with specific recognition peptides as well as with whole collagen molecules, could improve the boneintegration of implants to be used in bone tissue repairing
Gastric aspiration and its role in airway inflammation
Gastro-Oesophageal Reflux (GOR) has been associated with chronic airway diseases while the passage of foreign matter into airways and lungs through aspiration has the potential to initiate a wide spectrum of pulmonary disorders. The clinical syndrome resulting from such aspiration will depend both on the quantity and nature of the aspirate as well as the individual host response. Aspiration of gastric fluids may cause damage to airway epithelium, not only because acidity is toxic to bronchial epithelial cells but also due to the effect of digestive enzymes such as pepsin and bile salts. Experimental models have shown that direct instillation of these factors to airways epithelia cause damage with a consequential inflammatory response. The pathophysiology of these responses is gradually being dissected, with better understanding of acute gastric aspiration injury, a major cause of acute lung injury, providing opportunities for therapeutic intervention and potentially, ultimately, improved understanding of the chronic airway response to aspiration. Ultimately, clarification of the inflammatory pathways which are related to micro-aspiration via pepsin and bile acid salts may eventually progress to pharmacological intervention and surgical studies to assess the clinical benefits of such therapies in driving symptom improvement or reducing disease progression
Follow up of a cohort of intravenous heroin users in north and south central Dublin and in Dun Laoghaire.
Three studies of intravenous heroin users, in electoral wards in the north and south of central Dublin and in Dun Laoghaire, were undertaken in 1982-84. One hundred and one out of 203 intravenous injectors in these three studies are known to have been tested in Dublin for infection by the Human Immunodeficiency Virus (HIV) and 87 of the 101, or 86% are HIV Positive. Ninety two had also been tested for Hepatitis B infection (Hab) and 76 of the 92 were positive for the hepatitis antigen. The majority of those at present known to be HIV Positive in the Republic of Ireland are, or were, intravenous drug users
Photobiomodulation of human dermal fibroblasts in vitro: decisive role of cell culture conditions and treatment protocols on experimental outcome
YesPhotobiomodulation-based (LLLT) therapies show tantalizing promise for treatment of skin diseases. Confidence in this approach is blighted however by lamentable inconsistency in published experimental designs, and so complicates interpretation. Here we interrogate the appropriateness of a range of previously-reported treatment parameters, including light wavelength, irradiance and radiant exposure, as well as cell culture conditions (e.g., serum concentration, cell confluency, medium refreshment, direct/indirect treatment, oxygen concentration, etc.), in primary cultures of normal human dermal fibroblasts exposed to visible and near infra-red (NIR) light. Apart from irradiance, all study parameters impacted significantly on fibroblast metabolic activity. Moreover, when cells were grown at atmospheric O2 levels (i.e. 20%) short wavelength light inhibited cell metabolism, while negligible effects were seen with long visible and NIR wavelength. By contrast, NIR stimulated cells when exposed to dermal tissue oxygen levels (approx. 2%). The impact of culture conditions was further seen when inhibitory effects of short wavelength light were reduced with increasing serum concentration and cell confluency. We conclude that a significant source of problematic interpretations in photobiomodulation reports derives from poor optimization of study design. Further development of this field using in vitro/ex vivo models should embrace significant standardization of study design, ideally within a design-of-experiment setting
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Reliability in the whole life cycle of building systems
Purpose – The purpose of this research is to show that reliability analysis and its implementation will lead to an improved whole life performance of the building systems, and hence their life cycle costs (LCC).
Design/methodology/approach – This paper analyses reliability impacts on the whole life cycle of building systems, and reviews the up-to-date approaches adopted in UK construction, based on questionnaires designed to investigate the use of reliability within the industry.
Findings – Approaches to reliability design and maintainability design have been introduced from the operating environment level, system structural level and component level, and a scheduled maintenance logic tree is modified based on the model developed by Pride. Different stages of the whole life cycle of building services systems, reliability-associated factors should be considered to ensure the system's whole life performance. It is suggested that data analysis should be applied in reliability design, maintainability design, and maintenance policy development.
Originality/value – The paper presents important factors in different stages of the whole life cycle of the systems, and reliability and maintainability design approaches which can be helpful for building services system designers. The survey from the questionnaires provides the designers with understanding of key impacting factors
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