979 resultados para journal bearing
Resumo:
Issues have also individual titles.
Resumo:
Title varies slightly.
Resumo:
A high yielding synthesis of the pentacyclic diene-dione 1 has enabled investigation of its reactivity as a double dienophile in Diels-Alder [4+2] cycloadditions with isobenzofuran, leading to novel and highly symmetrical three-sided cavitands 3 and 4.
Type 1 nitrergic (ND1) cells of the rabbit retina: Comparison with other axon-bearing amacrine cells
Resumo:
NADPH diaphorase (NADPHd) histochemistry labels two types of nitrergic amacrine cells in the rabbit retina. Both the large ND1 cells and the small ND2 cells stratify in the middle of the inner plexiform layer, and their overlapping processes produce a dense plexus, which makes it difficult to trace the morphology of single cells. The complete morphology of the ND1 amacrine cells has been revealed by injecting Neurobiotin into large round somata in the inner nuclear layer, which resulted in the labelling of amacrine cells whose proximal morphology and stratification matched those of the ND1 cells stained by NADPHd histochemistry. The Neurobiotin-injected ND1 cells showed strong homologous tracer coupling to surrounding ND1 cells, and double-labelling experiments confirmed that these coupled cells showed NADPHd reactivity. The ND1 amacrine cells branch in stratum 3 of the inner plexiform layer, where they produce a sparsely branched dendritic tree of 400-600 mum diameter in ventral peripheral retina. In addition, each cell gives rise to several fine beaded processes, which arise either from a side branch of the dendritic tree or from the tapering of a distal dendrite. These axon-like processes branch successively within the vicinity of the dendritic field before extending, with little or no further branching, for 3-5 mm from the soma in ventral peripheral retina. Consequently, these cells may span one-third of the visual field of each eye, and their spatial extent appears to be greater than that of most other types of axon-bearing amacrine cells injected with Neurobiotin in this study. The morphology and tracer-coupling pattern of the ND1 cells are compared with those of confirmed type 1 catecholaminergic cells, a presumptive type 2 catecholaminergic cell, the type 1 polyaxonal. cells, the long-range amacrine cells, a novel type of axon-bearing cell that also branches in stratum 3, and a type of displaced amacrine cell that may correspond to the type 2 polyaxonal cell. (C) 2004 Wiley-Liss, Inc.
Resumo:
At 38 sites in the dry sclerophyll forests of south-east Queensland, Australia, hollow-bearing trees were studied to determine the effects of past forestry practices on their density, size and spatial distribution. The density of hollow-bearing trees was reduced at sites that had been altered by poisoning and ringbarking of unmerchantable trees. This was especially the case for living hollow-bearing trees that were now at densities too low to support the full range of arboreal marsupials. Although there are presently enough hollow-bearing stags (i.e., dead hollow-bearing trees) to provide additional denning and nesting opportunities, the standing life of these hollow-bearing stags is lower than the living counterparts which means denning and nesting sites may be limited in the near future. The mean diameter at breast height (DBH) of hollow-bearing stags was significantly less than that of living hollow-bearing trees. This indicated that many large hollow-bearing stags may have a shorter standing life than smaller hollow-bearing stags. Hollow-bearing trees appear to be randomly distributed throughout the forest in both silviculturally treated and untreated areas. This finding is at odds with the suggestion by some forest managers that hollow-bearing trees should have a clumped distribution in dry sclerophyll forests of south-east Queensland.
Resumo:
Tetrapeptide analogue H-[Glu-Ser-Lys(Thz)]-OH, containing a turn-inducing thiazole constraint, was used as a template to produce a 21-membered structurally characterized loop by linking Glu and Lys side chains with a Val-Ile dipeptide. This template was oligomerized in one pot to a library (cyclo-[1](n), n = 2-10) of giant symmetrical macrocycles (up to 120-membered rings), fused to 2-10 appended loops that were carried intact through multiple oligomerization (chain extension) and cyclization (chain terminating) reactions of the template. A three-dimensional solution structure for cyclo-[1](3) shows all three appended loops projecting from the same face of the macrocycle. This is a promising approach to separating pepticle motifs over large distances.
Resumo:
Extensive loss of adipose tissue is a hallmark of cancer cachexia but the cellular and molecular basis remains unclear. This study has examined morphologic and molecular characteristics of white adipose tissue in mice bearing a cachexia-inducing tumour, MAC16. Adipose tissue from tumour-bearing mice contained shrunken adipocytes that were heterogeneous in size. Increased fibrosis was evident by strong collagen-fibril staining in the tissue matrix. Ultrastructure of 'slimmed' adipocytes revealed severe delipidation and modifications in cell membrane conformation. There were major reductions in mRNA levels of adipogenic transcription factors including CCAAT/enhancer binding protein alpha (C/EBPα), CCAAT/enhancer binding protein beta, peroxisome proliferator-activated receptor gamma, and sterol regulatory element binding protein-1c (SREBP-1c) in adipose tissue, which was accompanied by reduced protein content of C/EBPα and SREBP-1. mRNA levels of SREBP-1c targets, fatty acid synthase, acetyl CoA carboxylase, stearoyl CoA desaturase 1 and glycerol-3-phosphate acyl transferase, also fell as did glucose transporter-4 and leptin. In contrast, mRNA levels of peroxisome proliferators-activated receptor gamma coactivator-1alpha and uncoupling protein-2 were increased in white fat of tumour-bearing mice. These results suggest that the tumour-induced impairment in the formation and lipid storing capacity of adipose tissue occurs in mice with cancer cachexia. © 2006 Cancer Research UK.
Resumo:
Purpose: A variety of biomass plantations are being raised for energy production. This case study is on energy production potential of seasonal oil bearing crops in India. These crops have the advantage of producing oil (liquid fuel) as well as biomass as agro residue (solid fuel). The purpose of the study is to estimate total energy yields of oil bearing crops and compare with other types of energy plantations. Also oil bearing crops bioaccumulate metals and thus phytoremediate soil. This provides scope for waste water irrigation. Design/methodology/approach: Relevant published papers on energy production by raising oil bearing crops have been analyzed. The effect of waste water irrigation and agronomic practices on increasing productivity is given special attention. Findings: It is shown that the seasonal oil bearing crops such as castor have a high potential to generate energy and this is comparable to energy produced by many perennial grasses. The energy yields of castor under irrigated condition was 196×103 MJ/ha and this is comparable to the reed canary grass which yields 195×103 MJ/ha. Some of the oil bearing crops are also super accumulators of certain toxic metals. Research limitations/implications: In this study, only all the accessible papers on the topic could be analyzed. Practical implications: This case study indicates that raising oil bearing crops such as castor using waste water has many advantages which include high energy yields, utilization of waste water for productive purpose and phytoremediation of soil. Originality/value: The comparison made between various types of energy crops for their energy generation is an original contribution. Findings of economic and environmental benefits by waste water irrigation are also of value. © Emerald Group Publishing Limited.
Resumo:
Fatigue crack propagation, tensile and fracture toughness data for four aeroengine bearing steels are reported. The steels involved are the through-hardened tool steels 18-4-1 (T1) and M50, and two similar carburized steels, RBD and Volvic. Crack growth data have been obtained at 20 °C and 280 °C to cover the range of oil temperatures experienced in aeroengine bearing operations. At 20 °C threshold ΔK values (ΔKth) ranged between 3.5 and 4.5 MPa √m with Paris exponents (m) of between 2.0 and 3.5. The lowest m-values were seen in the carburizing steels, which also exhibited lower Paris regime crack growth rates than M50 and 18-4-1. For all the steels, growth rates were higher at 280 °C,than 20 °C, although there was a slight tendency for ΔKth to increase, probably associated with oxide-induced closure at 280 °C. The effects of primary carbides, strength and toughness on fatigue crack growth behaviour are discussed, in relation to the importance of static-mode cracking. © 1990.
Resumo:
I am afraid that I need to challenge the assertion made by Rachel Airley in her letter (PJ, 10 March 2012, p308) that “there is no clear cut evidence that UCAS points obtained at school have any bearing on final degree performance”. Research from the Higher Education Funding Council for England — the body responsible for the distribution of funding to universities in England — shows that educational attainment before entry to higher education (ie, A-level grades) is the most important factor in determining academic success on undergraduate degree programmes.1,2 Indeed, research I have recently conducted on a cohort of MPharm students at Aston University (which will hopefully be published in a peer-reviewed academic journal shortly) demonstrates a strong positive correlation between UCAS Tariff points per A-level and final degree classification. As Dr Airley highlights in her letter, competition for places on MPharm programmes remains fierce and, in response to high levels of demand, her own institution has increased its standard entry offer. If UCAS Tariff points have little predictive ability of performance on the MPharm programme then, aside from minimising the administrative burden that the admissions process places on an institution, what is the logic behind increasing standard entry offers?
Resumo:
Objective. The prevalence of smoking in Aboriginal Canadians is higher than non-Aboriginal Canadians, a behavior that also tends to alter dietary patterns. Compared with the general Canadian population, maternal smoking rates are almost twice as high. The aim of this study was to compare dietary adequacy of Inuvialuit women of childbearing age comparing smokers versus non-smokers. Research methods & procedures. A cross-sectional study, where participants completed a culturally specific quantitative food frequency questionnaire. Non-parametric analysis was used to compare mean nutrient intake, dietary inadequacy and differences in nutrient density among smokers and non-smokers. Multiple logistic regression analyses were performed for key nutrients inadequacy and smoking status. Data was collected from three communities in the Beaufort Delta region of the Northwest Territories, Canada from randomly selected Inuvialuit women of childbearing age (19-44 years). Results: Of 92 participants, 75% reported being smokers. There were no significant differences in age, BMI, marital status, education, number of people in household working and/or number of self employed, and physical activity between smokers and non-smokers. Non-parametric analysis showed no differences in nutrient intake between smokers and non-smokers. Logistic regression however revealed there was a positive association between smoking and inadequacies of vitamin C (OR = 2.91, 95% CI, 1.17-5.25), iron (OR = 3.16, 95% CI, 1.27-5.90), and zinc (OR = 2.78, 95% CI, 1.12-4.94). A high percentage of women (>60%), regardless of smoking status, did not meet the dietary recommendations for fiber, vitamin D, E and potassium. Conclusions: This study provides evidence of inadequate dietary intake among Inuvialuit of childbearing age regardless of smoking behavior.
Resumo:
Although the primary objective on designing a structure is to support the external loads, the achievement of an optimal layout that reduces all costs associated with the structure is an aspect of increasing interest. The problem of finding the optimal layout for bridgelike structures subjected to a uniform load is considered. The problem is formulated following a theory on economy of frame structures, using the stress volume as the objective function and including the selection of appropriate values for statically indeterminate reactions. It is solved in a function space of finite dimension instead of using a general variational approach, obtaining near-optimal solutions. The results obtained with this profitable strategy are very close to the best layouts known to date, with differences of less than 2% for the stress volume, but with a simpler layout that can be recognized in some real bridges. This strategy could be a guide to preliminary design of bridges subject to a wide class of costs.
Resumo:
Purpose: To evaluate the antitumor activity of doxorubicine (DOX)-loaded nanoemulsion (NE) on Ehrlich ascites carcinoma (EAC)-bearing Swiss albino mice. Methods: The mice were divided into five groups (n = 20) according to the administered drug. Groups I - V were labeled as negative control (normal), positive control of the untreated EAC bearing mice (EAC control), blank nanoemulsion (BI-NE), DOX-loaded-NE (DOX/LNE) and free DOX (DOX-Sol), respectively. Cardiotoxicity was assessed by measuring changes in body and organ weight, analyzing serum enzymes and lipids, and examining histological changes in heart tissues by light microscopy. In addition, mean survival time (MST), increase in life span (ILS) and survival (S) of the mice were determined. Results: DOX/LNE group reduced levels of serum enzymes and lowered damage to heart tissues relative to DOX-Sol group. The MST of the DOX/LNE group (80 ± 0.0 days) was significantly greater than that for DOX-Sol group (34.6 ± 8.9 days), while ILS of DOX/LNE (265.30 days) was higher than that of DOX-Sol (57.99 days) by 4.6-fold. Conclusion: Administration of DOX/LNE to EAC-bearing mice improves the efficacy of DOX and reduce its side effects on the heart.