Strategies for revealing deformation and wear mechanisms of polymer composites by combining scanning electron microscopy,energy dispersive x-ray spectroscopy and cross-section techniques—Exemplified by glass fiber reinforced poly-phenylene-sulphide

Polymers and polymer composites are frequently used in tribological applications. However, their use is often limited by excessive wear or plastic deformation, therefore research and development aiming to improve the materials is ongoing. Tribological evaluations of polymer composites often study the friction coefficient and wear rate for different types, sizes and amounts of fillers. But rarely are any mechanisms presented. Although polymer materials differ from metals, the techniques typically used for metal components, for example, scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS), can be adapted to polymer materials, to achieve more informative SEM micrographs and EDS analyses. The aim of this article is to present useful analysis strategies, from sample preparation and selection of viewing angles, to selection of instrument settings and detector types. The strategies are exemplified by analysis of poly-phenylene-sulphide filled with glass fiber, evaluated against steel in a reciprocating ball-on-flat test set-up. This article takes its starting point with the worn surfaces, and subsequently analyze them using SEM and EDS. A selection of cross section preparation techniques, analysis parameters and microscopy settings are presented and discussed. By combining these techniques and settings, the observation of a strongly modified surface layer, as well as sub-surface plastic deformation and imbedded wear particles, is facilitated.     

Antiulcerogenic Potential of the Ethanolic Extract of Ceiba speciosa (A. St.-Hil.) Ravenna Evaluated by In Vitro and In Vivo Studies

Gastrointestinal diseases, such as peptic ulcers, are caused by a damage in the gastric mucosa provoked by several factors. This stomach injury is regulated by many inflammatory mediators and is commonly treated with proton-pump inhibitors, histamine H2 receptor blockers and antacids. However, various medicinal plants have demonstrated positive effects on gastric ulcer treatment, including plants of the Ceiba genus. The aim of this study was to evaluate the antiulcer and anti-inflammatory activities of the stem bark ethanolic extract of Ceiba speciosa (A. St.-Hil.) Ravenna. We performed a preliminary quantification of phenolic compounds by high-performance liquid chromatography-diode array detection (HPLC-DAD), followed by the prospection of other chemical groups through nuclear magnetic resonance (NMR) spectroscopy. A set of in vitro assays was used to evaluate the extract potential regarding its antioxidant activity (DPPH: 19.83 ± 0.34 µg/mL; TPC: 307.20 ± 6.20 mg GAE/g of extract), effects on cell viability and on the release of TNF-α in whole human blood. Additionally, in vivo assays were performed to evaluate the leukocyte accumulation and total protein quantification in carrageenan-induced air pouch, as well as the antiulcerogenic effect of the extract on an ethanol-induced ulcer in rats. The extract contains flavonoids and phenolic compounds, as well as sugars and quinic acid derivatives exhibiting potent antioxidant activity and low toxicity. The extract reduced the release of TNF-α in human blood and inhibited the activity of p38α (1.66 µg/mL), JAK3 (5.25 µg/mL), and JNK3 (8.34 µg/mL). Moreover, it reduced the leukocyte recruitment on the pouch exudate and the formation of edema, reverting the effects caused by carrageenan. The extract presented a significant prevention of ulcer formation and a higher reduction than the reference drug, Omeprazole. Therefore, C. speciosa extract has demonstrated relevant therapeutic potential for the treatment of gastric diseases, deserving the continuation of further studies to unveil the mechanisms of action of plant bioactive ingredients.     

Calcitriol Reduces the Inflammation,Endothelial Damage and Oxidative Stress in AKI Caused by Cisplatin

Cisplatin treatment is one of the most commonly used treatments for patients with cancer. However, thirty percent of patients treated with cisplatin develop acute kidney injury (AKI). Several studies have demonstrated the effect of bioactive vitamin D or calcitriol on the inflammatory process and endothelial injury, essential events that contribute to changes in renal function and structure caused by cisplatin (CP). This study explored the effects of calcitriol administration on proximal tubular injury, oxidative stress, inflammation and vascular injury observed in CP-induced AKI. Male Wistar Hannover rats were pretreated with calcitriol (6 ng/day) or vehicle (0.9% NaCl). The treatment started two weeks before i.p. administration of CP or saline and was maintained for another five days after the injections. On the fifth day after the injections, urine, plasma and renal tissue samples were collected to evaluate renal function and structure. The animals of the CP group had increased plasma levels of creatinine and of fractional sodium excretion and decreased glomerular filtration rates. These changes were associated with intense tubular injury, endothelial damage, reductions in antioxidant enzymes and an inflammatory process observed in the renal outer medulla of the animals from this group. These changes were attenuated by treatment with calcitriol, which reduced the inflammation and increased the expression of vascular regeneration markers and antioxidant enzymes.     

Surface energy measurements from Griffith cracks in boron fibres

Journal of Materials Science -     

Decrease in cardiovascular disease mortality in the Czech Republic from 1984 to 1993 and its possible causes

BACKGROUND: The objective of the investigation was to evaluate the ten-year development of the cardiovascular mortality rate in two population groups in the age bracket from 25 to 64 years, i.e. in subjects living in six districts which participated in the international WHO project MONICA and in the population of the whole Czech Republic. METHODS AND RESULTS: Data on the mortality rate in 1984-1993 for the age group from 25-64 years were provided by the Institute of Health Information and Statistics, information on the prevalence of risk factors was obtained in three cross-sectional studies implemented in six districts as part of the MONICA project in 1985, 1988 and 1992. In the mortality rate per 100,000 population in the six districts the following changes were revealed (in parentheses the values for 1984 and 1993 are given): men - a statistically significant declining trend in the from all caused mortality (849.3-742.5; p < 0.001) and cardiovascular mortality (367.2-280.4; p < 0.001) and cerebrovascular mortality (69.7-44.8; p < 0.001). In the mortality from ischaemic heart disease (215.7-170.6; ns) a declining trend was not recorded. In women aged 25-64 years in the six districts there was a statistically significant decline of the mortality from all caused (359.5-322.1; p < 0.001), the cardiovascular mortality (115.6-100.6; p < 0.001) and cerebrovascular mortality (31.1-23.6; p < 0.001). The mortality from ischaemic heart disease did not change (49.2-48.8; ns). In the population of the Czech Republic in men the following were detected: a drop of the from all caused mortality (907.1-784.8; P < 0.001), the cardiovascular mortality (383.5-308.4; p < 0.001) and cerebrovascular mortality (76.5-55.3; p < 0.001). Also in women of the Czech Republic a decline of the mortality from all caused was recorded (390.1-328.5; p < 0.001), the cardiovascular mortality (135.3-103.8; p < 0.001), ischaemic heart disease (58.0-48.6; p < 0.001) and cerebrovascular mortality (43.5-27.4; p < 0.001). In 1990 an increased cardiovascular mortality was recorded in men different from the trend during 1984-1993, statistically significant in the Czech Republic (p < 0.05) and in the six districts (p < 0.05). The reasons of this trend are not clear. The role of health services in the mortality drop is not clear, although available data indicate their improvement. Favourable changes were found in risk factors: during the period from 1985-1992 the prevalence of hypercholesterolaemia declined significantly in men and women, the prevalence of hypertension in women and the prevalence of smoking in men declined in the six districts. From nationwide data ensues that after 1989 significant changes occurred in the diet of the Czech population. The meat consumption declined by 1993 by 13%, the milk and dairy product consumption by 26.8% the butter consumption by 43.6% the consumption of vegetable fats increased by 16%, of vegetables by 8%, tropical fruit by 43.2%. These changes probably had an impact on the cholesterol level and BMI of the Czech population. CONCLUSIONS: In the declining cardiovascular mortality trend during 1984-1993 the following may have participated: improved medical care, dietary changes, improvement of the risk profile and other, in particular socioeconomic factors. With regard to the close temporal association of the investigated changes it may be assumed that this development is at least partly associated with changes of the political and economic position in the Czech Republic after 1989.     

Walter V. Bingham's Library.

Reports on the donation of her husband's library by Millicent Todd Bingham to the Department of Psychology at the University of Oslo, Norway. During the German occupation the library belonging to the Department of Psychology in Oslo was nearly all lost. The Bingham collection (close to 600 volumes plus periodicals) gives a picture of Walter Bingham's wide interests in the field of psychology and its classical works. This generous and invaluable gift will make studies richer and the work more fruitful among Norwegian psychologists both in the present and in generations to come. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Boreal freshwater fish diet modifies the plasma lipids and prostanoids and membrane fatty acids in man

The effect of fish diet on 43 healthy male students was studied. They ate a fish-containing meal for 15 weeks on an average of 3.7 times per week. Twenty-one of them voluntarily restricted their lipid intake while the rest ate normally. Controls continued their usual eating habits (19 students). The meals consisted of Finnish freshwater fish (87%) (vendace, pike, perch and rainbow trout) and brackish water fish (13%) (Baltic herring) that provided about 1 g of ω-3 polyunsaturated fatty acids per day (0.25 g eicosapentaenoic acid and 0.55 g docosahexaenoic acid). During the diet, ω-3 fatty acids increased in erythrocyte ghosts and platelets at the expense of ω-6 fatty acids. The concentration of serum cholesterol diminished in those fish consumers who lowered their lipid intake. Apolipo-protein A₁ and B were lowered in both fish-consuming groups. Triglyceride levels also showed a tendency to decrease. The formation of thromboxane B₂ during incubation of whole blood decreased in both fish-consuming groups. The decrease of plasma 6-keto-PGF_1α was not statistically significant, if compared with the controls. The results obtained indicate that a moderate intake of fish-containing meals has some beneficial effects on the plasma lipid and prostanoid metabolism, when coronary heart disease risk factors are considered.     

Theory and applications of self-tuning regulators

This paper reviews work on self-tuning regulators. The regulator algorithms, their theory and industrial applications are reviewed. The paper is expository—the major ideas are covered but detailed analysis is given elsewhere.