223 research outputs found

    Development of small bore, high speed tapered roller bearing

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    The performance of four rolling bearing configurations for use on the input pinion shaft of a proposed commercial helicopter transmission was evaluated. The performance characteristics of a high speed tapered roller bearing operating under conditions comparable to those existing at this input pinion shaft were defined. The tapered roller bearing shaft support configuration was developed for the gearbox using commercially available bearing designings. The configuration was optimized and interactive thermomechanically system analyzed. Automotive pinion quality tapered roller bearings were found to be reliable under load and speed conditions in excess of those anticipated in the helicopter transmission. However, it is indicated that the elastohydrodynamic lubricant films are inadequate

    Metabolic engineering of astaxanthin biosynthesis in maize endosperm and characterization of a prototype high oil hybrid

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    Maize was genetically engineered for the biosynthesis of the high value carotenoid astaxanthin in the kernel endosperm. Introduction of a β-carotene hydroxylase and a β-carotene ketolase into a white maize genetic background extended the carotenoid pathway to astaxanthin. Simultaneously, phytoene synthase, the controlling enzyme of carotenogenesis, was over-expressed for enhanced carotenoid production and lycopene ε-cyclase was knocked-down to direct more precursors into the β-branch of the extended ketocarotenoid pathway which ends with astaxanthin. This astaxanthin-accumulating transgenic line was crossed into a high oil- maize genotype in order to increase the storage capacity for lipophilic astaxanthin. The high oil astaxanthin hybrid was compared to its astaxanthin producing parent. We report an in depth metabolomic and proteomic analysis which revealed major up- or down- regulation of genes involved in primary metabolism. Specifically, amino acid biosynthesis and the citric acid cycle which compete with the synthesis or utilization of pyruvate and glyceraldehyde 3-phosphate, the precursors for carotenogenesis, were down-regulated. Nevertheless, principal component analysis demonstrated that this compositional change is within the range of the two wild type parents used to generate the high oil producing astaxanthin hybrid

    Conduction in ulnar nerve bundles that innervate the proximal and distal muscles: a clinical trial

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    <p>Abstract</p> <p>Background</p> <p>This study aims to investigate and compare the conduction parameters of nerve bundles in the ulnar nerve that innervates the forearm muscles and hand muscles; routine electromyography study merely evaluates the nerve segment of distal (hand) muscles.</p> <p>Methods</p> <p>An electrophysiological evaluation, consisting of velocities, amplitudes, and durations of ulnar nerve bundles to 2 forearm muscles and the hypothenar muscles was performed on the same humeral segment.</p> <p>Results</p> <p>The velocities and durations of the compound muscle action potential (CMAP) of the ulnar nerve bundle to the proximal muscles were greater than to distal muscles, but the amplitudes were smaller.</p> <p>Conclusions</p> <p>Bundles in the ulnar nerve of proximal muscles have larger neuronal bodies and thicker nerve fibers than those in the same nerve in distal muscles, and their conduction velocities are higher. The CMAPs of proximal muscles also have smaller amplitudes and greater durations. These findings can be attributed to the desynchronization that is caused by a wider range of distribution in nerve fiber diameters.</p> <p>Conduction parameters of nerve fibers with different diameters in the same peripheral nerve can be estimated.</p

    Analysis of Microplastics in Food Samples

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    This chapter presents a compilation of the analytical techniques used to detect and analyze microplastics in food. A detailed description of microplastics found in different samples is provided as well as an estimate of the annual intake of these particles. A total of 22–37 milligrams of microplastics per year was found. The factors that can influence the presence of particles in food, especially table salt, are discussed, showing that a background presence of microplastics in the environment can explain a large amount of experimental data.Support for this work was provided by the CTQ2016-76608-R project from the Ministry of Economy, Industry and Competitiveness (Spain) and by the University of Alicante under the project UAUSTI18-06

    Kinetic modelling of quantitative proteome data predicts metabolic reprogramming of liver cancer

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    BACKGROUND: Metabolic alterations can serve as targets for diagnosis and cancer therapy. Due to the highly complex regulation of cellular metabolism, definite identification of metabolic pathway alterations remains challenging and requires sophisticated experimentation. METHODS: We applied a comprehensive kinetic model of the central carbon metabolism (CCM) to characterise metabolic reprogramming in murine liver cancer. RESULTS: We show that relative differences of protein abundances of metabolic enzymes obtained by mass spectrometry can be used to assess their maximal velocity values. Model simulations predicted tumour-specific alterations of various components of the CCM, a selected number of which were subsequently verified by in vitro and in vivo experiments. Furthermore, we demonstrate the ability of the kinetic model to identify metabolic pathways whose inhibition results in selective tumour cell killing. CONCLUSIONS: Our systems biology approach establishes that combining cellular experimentation with computer simulations of physiology-based metabolic models enables a comprehensive understanding of deregulated energetics in cancer. We propose that modelling proteomics data from human HCC with our approach will enable an individualised metabolic profiling of tumours and predictions of the efficacy of drug therapies targeting specific metabolic pathways

    Plastic accumulation in the Mediterranean Sea

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    Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region

    Efeitos antinociceptivos e sedativos da buprenorfina, da acepromazina ou da associação buprenorfina e acepromazina em gatos

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    O efeito antinociceptivo da buprenorfina tem sido relatado em cães e gatos. No presente estudo, avaliou-se o limiar nociceptivo mecânico em felinos tratados com buprenorfina, acepromazina ou ambas associadas e foram comparados os efeitos antinociceptivos e sedativos da associação em relação ao uso isolado desses fármacos determinados pelo mesmo observador, por meio de analgesiômetro e da escala analógica visual dinâmica interativa (DIVAS), respectivamente. Os oito animais empregados no estudo foram previamente familiarizados com os procedimentos utilizados. Após quatro mensurações basais, foram administrados, por via intramuscular, 0,02mg kg-1 de buprenorfina, 0,06mg kg-1 de acepromazina ou 0,01mg kg-1 de buprenorfina associada a 0,03mg kg-1 de acepromazina, em um estudo cego, com delineamento em quadrado latino e tratamento semanal. Os efeitos antinociceptivos e sedativos foram avaliados aos 15, 30, 45 minutos e uma, duas, três, quatro, seis, oito e 12 horas após a administração do tratamento. O limiar nociceptivo mecânico se elevou significativamente apenas no grupo tratado com a associação buprenorfina-acepromazina (entre 45 minutos e uma hora). em relação à sedação, nos grupos tratados com acepromazina e com a associação, os valores da DIVAS foram significativamente maiores, respectivamente, de 15 minutos até quatro horas e de 15 minutos até três horas pós-tratamento, não apresentando elevação desses valores com a buprenorfina. Concluiu-se que não foi possível verificar a superioridade da neuroleptoanalgesia em relação ao uso dos fármacos isoladamente.The antinociceptive effects of buprenorphine have been reported in dogs and cats. This study evaluated changes in the mechanical nociceptive threshold and the sedative effects of buprenorphine, acepromazine and its combination in cats, determined by the same observer using a nociceptive threshold testing device and DIVAS, respectively. Eight animals were previously conditioned to the procedures. After four baseline measurements, 0.02mg kg-1 of buprenorphine, 0.06mg.kg-1 of acepromazine, or 0.01mg kg-1 of buprenorphine with 0.03mg kg-1 of acepromazine were administered intramuscularly in a blinded and experimental study using a Latin square design within a one week interval between treatments. The antinociceptive and sedative effects were evaluated at 15, 30, 45 minutes and 1, 2, 3, 4, 6, 8 and 12 hours post treatment. The nociceptive threshold increased significantly only after the combination buprenorphine-acepromazine (between 45 minutes and 1 hour). Regarding sedation, the use of acepromazine and the combination of both were associated with significantly higher DIVAS values from 15 minutes to 4 hours and 15 minutes to 3 hours post treatment, respectively. No increase in these values was noted with the use of buprenorphine. It was concluded that it could not be verified the superiority of neuroleptanalgesia over the use of drugs aloneFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Medicina Veterinária e Zootecnia Departamento de Cirurgia e Anestesiologia VeterináriaOntario Veterinary College Health Sciences CentreUniversity of California School of Veterinary Medicine Veterinary Medical Teaching HospitalUniversidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Medicina Veterinária e Zootecnia Departamento de Cirurgia e Anestesiologia Veterinári
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