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OALib Journal期刊

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Teste de proficiência para medi??es de radioatividade na medicina nuclear
Iwahara, Akira;Tauhata, Luiz;Oliveira, Antonio Eduardo de;Nícoli, Ieda Gomes;Alabarse, Frederico Gil;Xavier, Ana Maria;
Radiologia Brasileira , 2009, DOI: 10.1590/S0100-39842009000400013
Abstract: objective: to assess the performance of radionuclide calibrators in 55 brazilian nuclear medicine services in the measurement of 99tcm radiopharmaceutical activity. proficiency tests were applied to data sets with 63 results originated from the comparison program developed by laboratório nacional de metrologia das radia??es ionizantes of instituto de radioprote??o e dosimetria. materials and methods: the calibrators' performance was evaluated in compliance with the acceptance criterion of ±10% accuracy required by the brazilian standards and also the criteria established by the iso/iec guide 43-1, and classified as either "acceptable" or "non-acceptable". the samples of 99tcm utilized in the comparison were supplied by some of the participants and calibrated at laboratório nacional de metrologia das radia??es ionizantes for determining the activity reference value. results: the present study utilizing 99tcm has shown that 82.5% of the calibrators were considered as acceptable according to the brazilian standards, while by the criteria established by iso/iec 43-1, 81.0% were considered as acceptable. on the other hand, radionuclide calibrators with geiger-müller detectors presented unsatisfactory performance when compared with calibrators with ionization chambers. conclusion: the performance evaluation based on the iso/iec 43-1 criteria, which are applied to analytical laboratories, in spite of being more restrictive, has demonstrated to be quite consistent with the accuracy criterion established by the brazilian standard.
Fatores de corre??o volumétrica na medi??o de atividade de 99mTc e 123I em calibradores de radionuclídeos
Correia, Amanda Ribeiro;Iwahara, Akira;Tauhata, Luiz;Rezende, Eduarda Alexandre;Chaves, Tainá Olivieri;Oliveira, Antonio Eduardo de;Oliveira, Estela Maria de;
Radiologia Brasileira , 2012, DOI: 10.1590/S0100-39842012000200006
Abstract: objective: to determine correction factors for the variation in volume of radiopharmaceuticals in containers of different geometries, comparing the influence of such factors on the determination of 99mtc and 123i activity with two types of calibrators - one with ionization chamber and another with geiger-müller (g-m) detector -; and to evaluate calibrators performance in the measurement of 99mtc and 123i activities. materials and methods: eight calibrators, 10r glass vials, 3 and 5 ml plastic syringes and 99mtc and 123i solutions were utilized. the correction factors were determined with basis on practical measurements of the variation in the calibrators' response according to the volume of radionuclide solution in the glass vials. the performance was evaluated according to the acceptance criterion of ±10% accuracy required by the brazilian standard. results: the variation of the calibrators' response according to the variation in radionuclide volume was reasonably greater in the calibrator with g-m detector. it was also greater for 123i than for 99mtc. conclusion: the results confirm that the calibrators' response depends on the radionuclide volume contained in the vials. such dependence is more critical for the calibrators equipped with g-m detector and for 123i as compared with 99mtc.
Phosphorus Release from Sediments in a Riparian Phragmites australis Community at the Estuary of the Chikugogawa River, Western Japan  [PDF]
Akira Haraguchi
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.37114
Abstract: In order to determine the contribution of aquatic macrophyte communities on nutrition to sustain the high primary productivity of an estuary aquatic community, we analyzed the process of phosphorus release from sediments in aquatic macrophyte community in the estuary of the Chikugogawa River, South-Western Japan. Vertical profile of PD3-4 concentration and redox potential (Eh) of pore water in sediments were investigated within and outside the Phragmites australis community. Sediment horizon lower than 23 cm layer from the surface showed anaerobic (Eh < -200 mV) in the P. australis community, whereas sediment was constantly oxic (Eh > 0 mV) up to 50 cm depth outside the P. australis community without organic matter accumulation. Non-vegetated sediment with organic matter accumulation showed anoxic profile as vegetated site. PD3-4 concentration in anaerobic parts of sediment showed higher than oxic parts, and higher PD3-4 concentration in sediment pore water corresponded to sulfur deposition in sediment. Sulfate ion supplied from the sea water is reduced under the anoxic condition and S2- reacts with water-insoluble phosphorus salts e.g. Fe3(PO4)2 or AlPO4 and Fe2S3 or Al2S3 precipitates. Thus PD3-4 was mobilized and released under anoxic sediments. P. australis supply organic litter to sediment and the sediment within the P. australis community showed anoxic after aerobic decomposition of organic substances in sediment. Incubation of sediments under N2 atmosphere accumulated PD3-4 in the medium corresponding to low Eh (< -300 mV) showing that PD3-4 was released under anaerobic condition. Estuary P. australis community has function for supplying PD3-4 to river water.
Analysis of the Tracer Diffusion Phenomena through Cracks in the Porous Media by Means of X-Ray CT  [PDF]
Akira Sato
Materials Sciences and Applications (MSA) , 2013, DOI: 10.4236/msa.2013.48A003
Abstract:

The migration process of contamination materials in the porous rock mass was visualized and analyzed by X-ray CT image data. In this study, Kimachi sandstone, which had approximately 26% porosity, was used as a rock sample. Here two cases of diffusion phenomena were analyzed. One is the case that solute diffuses into the porous rock mass from the crack surfaces, and it simulates the contamination process of rock mass. Another is the case that the solute diffuses out of the porous rock mass, and it simulates the process that the contamination materials spread from highly contaminated sources. It was found that the diffusion phenomena were clearly visualized by X-ray CT method. By introducing the parameter, coefficient of tracer density increment α, quantitative analysis of tracer density became possible, and the relation between the density distribution of tracer and the crack apertures and the relation between the density distribution and porosity distribution became clear.

Effects of Salinity on Germination, Seedling Growth and Ecological Properties of Phragmites australis Communities in the Estuary of the Chikugogawa River, Southwestern Japan  [PDF]
Akira Haraguchi
American Journal of Plant Sciences (AJPS) , 2014, DOI: 10.4236/ajps.2014.55073
Abstract:

Salt tolerance of Phragmites australis populations was investigated in natural reed habitats in the estuary of the Chikugogawa River, southwestern Japan. P. australis populations were selected along the salinity gradient in the estuary, including limnetic (salinity 0.05%), oligohaline (0.4%) and polyhaline sections (2.5%). The ratio of Total-P/Total-N of river water showed high values in the oligohaline section and the above ground biomass, population height and culm diameter of P. australis showed maximum values in this section. Sufficient phosphorus supply could sustain the high productivity of the community in the oligohaline section, irrespective of the salinity of inundated water. The seed production of P. australis was lowest in the polyhaline section. Thus, the ecological performance of P. australis was highest in the oligohaline section and the performance declined with the increasing salinity of the habitat. The effects of salinity on germination and seedling growth were evaluated by means of cultivation in 0.0% -5.0% (NaCl w/w%) salinity medium. Seeds of P. australis collected from every natural population in the estuary failed to germinate at salinity levels above 2.3%. Growth of shoot length and above-ground biomass of seedlings germinated in the fresh water medium were measured for 21 days’ exposure to constant salinity solutions ranging from 0.0% -5.0%. Although mortality was high at salinity levels 3.5% and 5.0%, elongation of shoots of some plants was evident at a salinity level of 5.0%. Seeds from the population in the limnetic section

Extendibility Evaluation of Industrial EUV Source Technologies for kW Average Power and 6.x nm Wavelength Operation  [PDF]
Akira Endo
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.55039
Abstract:

Interests in the extendibility are growing after the introduction of the LPP (Laser Produced Plasma) EUV source technology in the semiconductor industry, towards higher average power and shorter wavelength, based on the basic architecture of the established LPP EUV source technology. It is discussed in this article that the power scaling of the 13.5nm wavelength source is essentially possible by a slight increase of the driving laser power, CE (Conversion Efficiency) and EUV collection efficiency by some introduction of novel component technologies. Extension of the EUV wavelength towards BEUV (Beyond EUV), namely 6.x nm is discussed based on the general rule of the UTA (Unresolved Transition Arrays) of high Z ions, and development of multilayer mirrors in this particular wavelength region. Technical difficulties are evaluated for the extension of the LPP source technology by considering the narrower mirror bandwidth and higher melting temperature of the candidate plasma materials. Alternative approach based on the superconducting FEL is evaluated in comparison with the LPP source technology for the future solution.

Effect of Degree of Cure on Sandwich Structural Capacitor Using Ion-Conductive Polymer with Carbon Fabric Skins  [PDF]
Akira Todoroki
Open Journal of Composite Materials (OJCM) , 2016, DOI: 10.4236/ojcm.2016.64011
Abstract: Structural capacitors are composite structures that function as energy storage capacitors. An electric double-layer capacitor with a composite structure using a solid polymer electrolyte matrix with a glass fiber fabric separator has recently been developed. In the present study, new foam core sandwich structure is adopted and the effect of the degree of cure is experimentally investigated. Carbon fiber fabric cloth is used as electrodes, and the polystyrene foam core is used as separator. Material system of Poly Ethylene Glycol DiGlycidyl Ether (PEGDGE) with Lithium bisTriFluoromethane Sulfonyl Imide (LiTFSI) and hardener of TriEthylene TetrAmine (TETA) is adopted as ion-conductive polymer matrix. The effect of the cure degree is experimentally investigated by using 100% cure degree, 70% cure degree and 0% cure degree specimens. As a result, the polystyrene foam-core sandwich system is proved to be effective, but the capacitance is not enough because of the lack of surface area of the carbon fiber electrodes. As the remained TETA impedes the movement of Li+ cation in the solid polymer by means of the segment-motion-assisted diffusion process, the low degree of cure causes small capacitance with this material system.
Factors Associated with the Walking Ability of Hemiplegic Stroke Patients  [PDF]
Akira Matsuyama
Open Journal of Nursing (OJN) , 2018, DOI: 10.4236/ojn.2018.81002
Abstract:
Gait disturbance due to motor paralysis affects activities of daily living and quality of life in patients with stroke. Thus, commencing walking training from the acute phase of recovery is essential. This study aimed to clarify the factors affecting the walking ability of hemiplegic stroke patients. Eighty hospitalized patients with a first chemic or hemorrhagic stroke within 1 year but not less than 1 month after stroke onset were included in this study. The dependent variable was walking ability (Functional Independence Measure [FIM] locomotion score), and the independent variables were spirituality (Spirituality Rating Scale-A [SRS-A]), amount of social support (Japanese version of the Abbreviated Multidimensional Scale of Perceived Social Support, frequency of family visit), stroke severity (National Institutes of Health Stroke Scale [NIHSS]), degree of motor paralysis (lower extremity Brunnstrom stage), the lower limb loading force of the affected and unaffected side, and age. Spearman’s rank correlation coefficient and multiple regression analysis were performed. Multiple regression analysis showed that FIM locomotion score was associated with NIHSS (standard partial regression coefficient =
Redes e alian?as estratégicas no Brasil: caso CVRD
Tauhata, Tatiana L.;Macedo-Soares, T. Diana L. V. A. de;
RAE eletr?nica , 2004, DOI: 10.1590/S1676-56482004000100004
Abstract: in the current highly competitive scenario, firms are increasingly establishing alliances and integrating networks to complement their resources, reduce uncertainties and sustain their competitiveness. this paper aims at highlighting the importance of taking into account in the management of firms embedded in strategic networks, the latter's implications for firm conduct and performance. it focusses on a brazilian company that is the leader in the iron ore business - cia vale do rio doce - using case study methodology and new conceptual tools for strategic assessment from a relational perspective. based on bibliographic, documental and empirical research, it shows how this perspective can provide new valuable insights for the strategic planning of the firm by revealing network implications, in terms of opportunities, threats, strengths and weaknesses, that reduce, neutralize or increase those identified by way of traditional strategic analyses.
Adaptive Method for State Estimation of Sound Environment System with Uncertainty and its Application to Psychological Evaluation  [PDF]
Hisako Orimoto, Akira Ikuta
Intelligent Information Management (IIM) , 2010, DOI: 10.4236/iim.2012.23025
Abstract: The actual sound environment system exhibits various types of linear and non-linear characteristics, and it often contains uncertainty. Furthermore, the observations in the sound environment are often in the level-quantized form. In this paper, two types of methods for estimating the specific signal for sound envi-ronment systems with uncertainty and the quantized observation are proposed by introducing newly a system model of the conditional probability type and moment statistics of fuzzy events. The effectiveness of the proposed theoretical methods is confirmed by applying them to the actual problem of psychological evalua-tion for the sound environment.
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