142 research outputs found

    Analisis Toolpath Variasi Zig Zag Dan Spiral Mesin CNC Router Terhadap Benda Kerja Berbahan Acrylic

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    The purpose of this research is to determine the feeding speed of two different toolpath due to the feeding speed variation in the making process of the acrylic based workpiece. This research discuss about the construction process of CNC machine with the early stage of preparing the tools and materials, and also designing and constructing the desired machine by using the aluminium and iron material. The next stage is preparing the acrylic based workpiece as the testing material. The machining process was conducted by applying the zig zag and spiral toolpath and the result of both toolpaths will be discussed. From the test result of zig zag toolpath, it was found that the highest cutting speed occurs at the feeding speed of 300mm/min, that was 34.852m/mm. While from the spiral toolpath, it showed that the highest cutting speed occurs at the feeding speed of 300mm/min, that was 35.958m/mm. It can be concluded that the higher the feeding speed, the higher the cutting speed as well. From these two toolpath, it is determined that the zig zag toolpath has the higher cutting speed than that of the spiral toolpath. Key words: Toolpath, CNC Router, Acryli

    Perfil antropométrico en adultos del Noroeste Argentino: comparación con una referencia internacional

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    Desde una perspectiva bioantropológica las mediciones antropométricas en adultos son exhaustivamente utilizadas en la evaluación morfológica de poblaciones argentinas extintas. La mayoría de los estudios antropométricos en adultos argentinos contemporáneos se limitan a la evaluación de talla, peso e IMC. El objetivo de este trabajo fue describir otras variables antropométricas en adultos del Noroeste argentino (NOA) y compararlas con una referencia internacional. Los datos de peso, talla, perímetros (brazo, muslo, pierna, cintura) y pliegues (tríceps, subescapular) proceden de 881 individuos (526 mujeres; 355 varones) sanos de 20-60 años de edad de distintas localidades de Catamarca y Jujuy. Se calcularon estadísticos descriptivos (media y DS) por sexo y dos grupos de edad: 20-39 y 40-60 años. Las comparaciones se establecieron con adultos de EEUU de origen mejicano (Centers for Disease Control, CDC 2003-2006) con la prueba t. Se calcularon los percentilos con el método LMS. En ambos sexos y grupos de edad los adultos del NOA presentaron valores significativamente inferiores a los de la referencia en todas las variables consideradas, excepto para pliegues tricipital y subescapular en varones de 40-60 años. No se han encontrado antecedentes antropométricos comparables semejantes para poblaciones argentinas y del NOA. El perfil antropométrico de los adultos del NOA difiere significativamente con respecto a la población de referencia con un origen étnico afín. Rev Arg Antrop Biol 17(1):07-18, 2015

    Use of fluorescence imaging and indocyanine green during colorectal surgery: Results of an intercontinental Delphi survey

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    BACKGROUND: Fluorescence imaging with indocyanine green is increasingly being used in colorectal surgery to assess anastomotic perfusion, and to detect sentinel lymph nodes. METHODS: In this 2-round, online, Delphi survey, 35 international experts were asked to vote on 69 statements pertaining to patient preparation and contraindications to fluorescence imaging during colorectal surgery, indications, technical aspects, potential advantages/disadvantages, and effectiveness versus limitations, and training and research. Methodological steps were adopted during survey design to minimize risk of bias. RESULTS: More than 70% consensus was reached on 60 of 69 statements, including moderate-strong consensus regarding fluorescence imaging's value assessing anastomotic perfusion and leak risk, but not on its value mapping sentinel nodes. Similarly, although consensus was reached regarding most technical aspects of its use assessing anastomoses, little consensus was achieved for lymph-node assessments. Evaluating anastomoses, experts agreed that the optimum total indocyanine green dose and timing are 5 to 10 mg and 30 to 60 seconds pre-evaluation, indocyanine green should be dosed milligram/kilogram, lines should be flushed with saline, and indocyanine green can be readministered if bright perfusion is not achieved, although how long surgeons should wait remains unknown. The only consensus achieved for lymph-node assessments was that 2 to 4 injection points are needed. Ninety-six percent and 100% consensus were reached that fluorescence imaging will increase in practice and research over the next decade, respectively. CONCLUSION: Although further research remains necessary, fluorescence imaging appears to have value assessing anastomotic perfusion, but its value for lymph-node mapping remains questionable

    Teeth of the red fox Vulpes vulpes (L., 1758) as a bioindicator in studies on fluoride pollution

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    An examination was made of fluoride content in the mandibular first molars of the permanent teeth of the red fox Vulpes vulpes living in north-west (NW) Poland. The teeth were first dried to a constant weight at 105°C and then ashed. Fluorides were determined potentiometrically, and their concentrations were expressed in dry weight (DW) and ash. The results were used to perform an indirect estimation of fluoride pollution in the examined region of Poland. The collected specimens (n = 35) were classified into one of the three age categories: immature (im, 6–12 months), subadult (subad, from 12 to 20 months) and adult (ad, >20 months). The mean concentrations (geometric mean) of fluoride were similar in the im and subad groups (230 and 296 mg/kg DW and 297 and 385 mg/kg ash, respectively), and significantly smaller than in the ad group (504 and 654 mg/kg, respectively, in DW and ash). Basing on other reports that the ∼400 mg/kg DW concentration of fluoride in bones in the long-lived wild mammals generally reflects the geochemical background, it was found that 57% of the foxes in NW Poland exceeded this value by 9% to 170%. This indirectly reflects a moderate fluoride contamination in the tested region

    Depression of glutamate and GABA release by presynaptic GABAB receptors in the entorhinal cortex in normal and chronically epileptic rats

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    Presynaptic GABAB receptors (GABABR) control glutamate and GABA release at many synapses in the nervous system. In the present study we used whole-cell patch-clamp recordings of spontaneous excitatory and inhibitory synaptic currents in the presence of TTX to monitor glutamate and GABA release from synapses in layer II and V of the rat entorhinal cortex (EC)in vitro. In both layers the release of both transmitters was reduced by application of GABABR agonists. Quantitatively, the depression of GABA release in layer II and layer V, and of glutamate release in layer V was similar, but glutamate release in layer II was depressed to a greater extent. The data suggest that the same GABABR may be present on both GABA and glutamate terminals in the EC, but that the heteroreceptor may show a greater level of expression in layer II. Studies with GABABR antagonists suggested that neither the auto- nor the heteroreceptor was consistently tonically activated by ambient GABA in the presence of TTX. Studies in EC slices from rats made chronically epileptic using a pilocarpine model of temporal lobe epilepsy revealed a reduced effectiveness of both auto- and heteroreceptor function in both layers. This could suggest that enhanced glutamate and GABA release in the EC may be associated with the development of the epileptic condition. Copyright © 2006 S. Karger AG
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