921 resultados para Shellfish harvesting
Resumo:
Tissue engineering is a popular topic in peripheral nerve repair. Combining a nerve conduit with supporting adipose-derived cells could offer an opportunity to prevent time-consuming Schwann cell culture or the use of an autograft with its donor site morbidity and eventually improve clinical outcome. The aim of this study was to provide a broad overview over promising transplantable cells under equal experimental conditions over a long-term period. A 10-mm gap in the sciatic nerve of female Sprague-Dawley rats (7 groups of 7 animals, 8 weeks old) was bridged through a biodegradable fibrin conduit filled with rat adipose-derived stem cells (rASCs), differentiated rASCs (drASCs), human (h)ASCs from the superficial and deep abdominal layer, human stromal vascular fraction (SVF), or rat Schwann cells, respectively. As a control, we resutured a nerve segment as an autograft. Long-term evaluation was carried out after 12 weeks comprising walking track, morphometric, and MRI analyses. The sciatic functional index was calculated. Cross sections of the nerve, proximal, distal, and in between the two sutures, were analyzed for re-/myelination and axon count. Gastrocnemius muscle weights were compared. MRI proved biodegradation of the conduit. Differentiated rat ASCs performed significantly better than undifferentiated rASCs with less muscle atrophy and superior functional results. Superficial hASCs supported regeneration better than deep hASCs, in line with published in vitro data. The best regeneration potential was achieved by the drASC group when compared with other adipose tissue-derived cells. Considering the ease of procedure from harvesting to transplanting, we conclude that comparison of promising cells for nerve regeneration revealed that particularly differentiated ASCs could be a clinically translatable route toward new methods to enhance peripheral nerve repair.
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Occupational exposures to fungi are very frequent and are known to cause chronic or acute symptoms. To better assess health risks related to fungal exposure, it is crucial to characterize precisely the airborne fungal community in terms of quantity and composition. The objective of this chapter is to synthesize existing knowledge of airborne fungal contamination in various occupational settings. We analyzed 134 papers published between 2000 and 2014 focusing on five different work sectors considered as highly contaminated (i.e., more than 1000 fungal particles/m3): animal confinement buildings, sawmills, waste handling, the food industry, and grain/plant handling. Results show that harvesting grain, washing cheese, and handling salami seem to be the occupational situations with the worst potential for exposure. Moreover, a lack of standardized sampling and analysis methods among countries and even within the same country is highlighted. Occupational exposure limit values do not exist. Recommendations and guidelines based on culture-dependent methods, which are now recognized to underestimate true concentrations, are proposed. Those recommendations are frequently exceeded and protective measures are not always easy to implement.
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Most fishes produce free-living embryos that are exposed to environmental stressors immediately following fertilization, including pathogenic microorganisms. Initial immune protection of embryos involves the chorion, as a protective barrier, and maternally-allocated antimicrobial compounds. At later developmental stages, host-genetic effects influence susceptibility and tolerance, suggesting a direct interaction between embryo genes and pathogens. So far, only a few host genes could be identified that correlate with embryonic survival under pathogen stress in salmonids. Here, we utilized high-throughput RNA-sequencing in order to describe the transcriptional response of a non-model fish, the Alpine whitefish Coregonus palaea, to infection, both in terms of host genes that are likely manipulated by the pathogen, and those involved in an early putative immune response. Embryos were produced in vitro, raised individually, and exposed at the late-eyed stage to a virulent strain of the opportunistic fish pathogen Pseudomonas fluorescens. The pseudomonad increased embryonic mortality and affected gene expression substantially. For example, essential, upregulated metabolic pathways in embryos under pathogen stress included ion binding pathways, aminoacyl-tRNA-biosynthesis, and the production of arginine and proline, most probably mediated by the pathogen for its proliferation. Most prominently downregulated transcripts comprised the biosynthesis of unsaturated fatty acids, the citrate cycle, and various isoforms of b-cell transcription factors. These factors have been shown to play a significant role in host blood cell differentiation and renewal. With regard to specific immune functions, differentially expressed transcripts mapped to the complement cascade, MHC class I and II, TNF-alpha, and T-cell differentiation proteins. The results of this study reveal insights into how P. fluorescens impairs the development of whitefish embryos and set a foundation for future studies investigating host pathogen interactions in fish embryos.
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The increase in seafood production, especially in mariculture worldwide, has brought out the need of continued monitoring of shellfish production areas in order to ensure safety to human consumption. The purpose of this research was to evaluate pathogenic protozoa, viruses and bacteria contamination in oysters before and after UV depuration procedure, in brackish waters at all stages of cultivation and treatment steps and to enumerate microbiological indicators of fecal contamination from production site up to depuration site in an oyster cooperative located at the Southeastern estuarine area of Brazil. Oysters and brackish water were collected monthly from September 2009 to November 2010. Four sampling sites were selected for enteropathogens analysis: site 1- oyster growth, site 2- catchment water (before UV depuration procedure), site 3 - filtration stage of water treatment (only for protozoa analysis) and site 4- oyster's depuration tank. Three microbiological indicators ! were examined at sites 1, 2 and 4. The following pathogenic microorganisms were searched: Giardia cysts, Cryptosporidium oocysts, Human Adenovirus (HAdV), Hepatitis A virus (HAV), Human Norovirus (HnoV) (genogroups I and II), JC strain Polyomavirus (JCPyV) and Salmonella sp. Analysis consisted of molecular detection (qPCR) for viruses (oysters and water samples); immunomagnetic separation followed by direct immunofluorescence assay for Cryptosporidium oocysts and Giardia cysts and also molecular detection (PCR) for the latter (oysters and water samples); commercial kit (Reveal-Neogee (R)) for Salmonella analysis (oysters). Giardia was the most prevalent pathogen in all sites where it was detected: 36.3%, 18.1%, 36.3% and 27.2% of water from sites 1, 2, 3 and 4 respectively; 36.3% of oysters from site 1 and 54.5% of depurated oysters were harboring Giardia cysts. The huge majority of contaminated samples were classified as Giardia duodenalis. HAdv was detected in water and o! ysters from growth site and HnoV GI in two batches of oysters ! (site 1) in huge concentrations (2.11 x 10(13), 3.10 x 10(12) gc/g). In depuration tank site, Salmonella sp., HAV (4.84 x 10(3)) and HnoV GII (7.97 x 10(14)) were detected once in different batches of oysters. Cryptosporidium spp. oocysts were present in 9.0% of water samples from site four. These results reflect the contamination of oysters even when UV depuration procedures are employed in this shellfish treatment plant. Moreover, the molecular comprehension of the sources of contamination is necessary to develop an efficient management strategy allied to shellfish treatment improvement to prevent foodborne illnesses. (C) 2011 Elsevier Ltd. All rights reserved.
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The aim of this work is to design a flywheel generator for a diesel hybrid working machine. In this work we perform detailed design of a generator. Mobile machines are commonly used in industry: road building machines, three harvesting machines, boring machines, trucks and other equipment. These machines work with a hydraulic drive system. This system provides good service property and high technical level. Manufacturers of mobile machines tend to satisfy all requirements of customers and modernized drive system. In this work also a description of the frequency inverter is present. Power electronics system is one of the basic parts for structures perform in the project.
Resumo:
Chronic exposure to airborne fungi has been associated with different respiratory symptoms and pathologies in occupational populations, such as grain workers. However, the homogeneity in the fungal species composition of these bioaerosols on a large geographical scale and the different drivers that shape these fungal communities remain unclear. In this study, the diversity of fungi in grain dust and in the aerosols released during harvesting was determined across 96 sites at a geographical scale of 560 km(2) along an elevation gradient of 500 m by tag-encoded 454-pyrosequencing of the internal transcribed spacer (ITS) sequences. Associations between the structure of fungal communities in the grain dust and different abiotic (farming system, soil characteristics, geographic and climatic parameters) and biotic (wheat cultivar, previous crop culture) factors were explored. These analyses revealed a strong relationship between the airborne and grain dust fungal communities and showed the presence of allergenic and mycotoxigenic species in most samples, which highlights the potential contribution of these fungal species to work-related respiratory symptoms of grain workers. The farming system was the major driver of the alpha and beta phylogenetic diversity of fungal communities. In addition, elevation and soil CaCO3 concentrations shaped the alpha diversity whereas wheat cultivar, cropping history and the number of freezing days per year shaped the taxonomic beta diversity of these communities.
Resumo:
Open educational resources (OER) promise increased access, participation, quality, and relevance, in addition to cost reduction. These seemingly fantastic promises are based on the supposition that educators and learners will discover existing resources, improve them, and share the results, resulting in a virtuous cycle of improvement and re-use. By anecdotal metrics, existing web scale search is not working for OER. This situation impairs the cycle underlying the promise of OER, endangering long term growth and sustainability. While the scope of the problem is vast, targeted improvements in areas of curation, indexing, and data exchange can improve the situation, and create opportunities for further scale. I explore the way the system is currently inadequate, discuss areas for targeted improvement, and describe a prototype system built to test these ideas. I conclude with suggestions for further exploration and development.
Resumo:
Seloste artikkelista: Jylhä, P. & Laitila, J. 2007. Energy wood and pulpwood harvesting from young stands using a prototype whole-tree bundler. Silva Fennica 41 (4) : 763-779
Resumo:
Nanoantennae show potential for photosynthesis research for two reasons; first by spatially confining light for experiments which require high spatial resolution, and second by enhancing the photon emission of single light-harvesting complexes. For effective use of nanoantennae a detailed understanding of the interaction between the nanoantenna and the light-harvesting complex is required. Here we report how the excitation and emission of multiple purple bacterial LH2s (light-harvesting complex 2) are controlled by single gold nanorod antennae. LH2 complexes were chemically attached to such antennae, and the antenna length was systematically varied to tune the resonance with respect to the LH2 absorption and emission. There are three main findings. (i) The polarization of the LH2 emission is fully controlled by the resonant nanoantenna. (ii) The largest fluorescence enhancement, of 23 times, is reached for excitation with light at λ = 850 nm, polarized along the long antenna-axis of the resonant antenna. The excitation enhancement is found to be 6 times, while the emission efficiency is increased 3.6 times. (iii) The fluorescence lifetime of LH2 depends strongly on the antenna length, with shortest lifetimes of [similar]40 ps for the resonant antenna. The lifetime shortening arises from an 11 times resonant enhancement of the radiative rate, together with a 2–3 times increase of the non-radiative rate, compared to the off-resonant antenna. The observed length dependence of radiative and non-radiative rate enhancement is in good agreement with simulations. Overall this work gives a complete picture of how the excitation and emission of multi-pigment light-harvesting complexes are influenced by a dipole nanoantenna.
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La Permacultura, los Paisajes de retención de agua y la Economía del bien común, se configuran como una alternativa a la situación actual de la agricultura. Mediante la combinación de estas corrientes, se puede desarrollar una agricultura más respetuosa con el entorno natural capaz de ayudar a regenerarlo. Una buena gestión del suelo fija y estabiliza el CO2 y gracias a los paisajes de captación de agua, se consigue cosechar el agua, infiltrándose en los ecosistemas y llenándolos de vida. Sumado a una correcta gestión del agua se mitigan los efectos del cambio climático en nuestras latitudes. Finalmente la economía del bien común, nos permite crear sistemas económicos más justos y sociales, encajando a la perfección con los principios de la Permacultura. Para poder aplicar dicho concepto actualmente, establecer el sistema agrícola como un sistema asociativo (asociación sin ánimo de lucro), nos permite fijar unos precios estables y sociales, dando especial importancia a la mano de obra y a la autosuficiencia.
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El Projecte intenta presentar totes les tasques realitzades durant l’estada de pràctiques a l’empresa on es pretenia musealitzar el Molí de Pals, canviant el seu ús industrial per a un nou ús social i turístic. Es pretén donar valor a aquest element patrimonial com un referent en la identitat dels palencs i aconseguir oferir un servei de qualitat al visitant adaptant-se a les necessitats de cada col•lectiu. Es tracten alguns temes com el cultiu de l’arròs i la seva evolució a Pals, els museus industrials i tipus d’equipaments visitables
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Salvage logging is a common practice carried out in burned forests worldwide, and intended to mitigate the economic losses caused by wildfires. Logging implies an additional disturbance occurring shortly after fire, although its ecological effects can be somewhat mitigated by leaving wood debris on site. The composition of the bird community and its capacity to provide ecosystem services such as seed dispersal offleshy-fruited plants have been shown to be affected by postfire logging. We assessedthe effects of the habitat structure resulting from different postfire management practices on the bird community, in three burned pine forests in Catalonia (western Mediterranean). For this purpose, we focused on the group of species that is responsible for seed dispersal, a process which takes place primarily during the winter in theMediterranean basin. In addition, we assessed microhabitat selection by seed disperser birds in such environments in relation to management practices. Our results showed a significant, positive relationship between the density of wood debris piles and the abundance of seed disperser birds. Furthermore, such piles were the preferredmicrohabitat of these species. This reveals an important effect of forest management on seed disperser birds, which is likely to affect the dynamics of bird-dependent seed dispersal. Thus, building wood debris piles can be a useful practice for the conservation of both the species and their ecosystem services, while also being compatible with timber harvesting
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Once the seed has germinated, the plant is forced to face all the environmental changes in its habitat. In order to survive, plants have evolved a number of different acclimation systems. The primary reaction behind plant growth and development is photosynthesis. Photosynthesis captures solar energy and converts it into chemical form. Photosynthesis in turn functions under the control of environmental cues, but is also affected by the growth, development, and metabolic state of a plant. The availability of solar energy fluctuates continuously, requiring non-stop adjustment of photosynthetic efficiency in order to maintain the balance between photosynthesis and the requirements and restrictions of plant metabolism. Tight regulation is required, not only to provide sufficient energy supply but also to prevent the damage caused by excess energy. The very first reaction of photosynthesis is splitting of water into the form of oxygen, hydrogen, and electrons. This most fundamental reaction of life is run by photosystem II (PSII), and the energy required for the reaction is collected by the light harvesting complex II (LHCII). Several proteins of the PSII-LHCII complex are reversibly phosphorylated according to the energy balance between photosynthesis and metabolism. Thylakoid protein phosphorylation has been under extensive investigation for over 30 years, yet the physiological role of phosphorylation remains elusive. Recently, the kinases behind the phosphorylation of PSII-LHCII proteins (STN7 and STN8) were identified and the knockout mutants of these kinases became available, providing powerful tools to elucidate the physiological role of PSII-LHCII phosphorylation. In my work I have used the stn7 and stn8 mutants in order to clarify the role of PSII-LHCII phosphorylation in regulation and protection of the photosynthetic machinery according to environmental cues. I show that STN7- dependent PSII-LHCII protein phosphorylation is required to balance the excitation energy distribution between PSII and PSI especially under low light intensities when the excitation energy transfer from LHC to PSII and PSI is efficient. This mechanism differs from traditional light quality-induced “state 1” – “state 2” transition and ensures fluent electron transfer from PSII to PSI under low light, yet having highest physiological relevance under fluctuating light intensity. STN8-dependent phosphorylation of PSII proteins, in turn, is required for fluent turn-over of photodamaged PSII complexes and has the highest importance upon prolonged exposure of the photosynthetic apparatus to excess light.
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The essential oils of the leaves and twigs from Zanthoxylum syncarpum Tull. were examined by GC/MS and GC-FID. Variation in the oil composition relative to the harvesting time was also described. The major components in the leaves oils were limonene (23.1-47.3%) and myrcene (4.8-10.8%). In the oils of twigs, the main components were ar-curcumene (12.8-18.1%), E-β-farnesene (9.1-9.7%) and β-caryophyllene (9.2-9.3%). This paper describes for the first time the composition of the essential oil of the twigs from Z. syncarpum.
Resumo:
The essential oil of the leaves of Lippia alba chemotype linalool-1,8-cineol was extracted by hidrodistillation at different seasons and analyzed by GC/MS. Qualitative and quantitative variations in regard to the period of harvesting have been performed and the results were correlated with meteorological data. The essential oil yield varied from 0.33 to 0.67%. The chemical diversity of the constituents increased throughout the year, being 1,8-cineol and linalool the major components. Possible biosynthetic routes of mono and sesquiterpenoids present in the essential oil are discussed.