262 research outputs found

    放射線エネルギーの違いによる喉頭癌における吸収線量の影響

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    We investigated the usefulness of Gafchromic MD-55 film (Nuclear Associates, Inc.) for measuring the radiation doses on the radiotherapy of laryngeal cancers. Since larynx has thin wedge-shaped structure in anterior neck adjacent to airway, the radiation doses to the lesion may be diminished because of build-up and build-down. So, the dose has been measured with conventional measuring systems such as thermoluminescent dosimetry (TLD). However, it was not possible to evaluate the dose distribution correctly using TLD, because it is impossible to float a TLD chip in an air cavity. In this study, we employed Gafchromic MD-55 film as a dosimeter, for it can be set on the area of interest and with a measurability of dose range of 3 to 100 Gy, though it has no energy dependency. And this radiometer is composition near the soft tissue of the human body. The dose distributions to larynx were investigated with this film using neck phantom under each radiation beam energy of 4, 6 and 10 MV x-rays. Our neck phantom is made from acrylic resin and simulates a normal larynx on the basis of image information of computed tomography (CT). Moreover we observed secondary build-up and build-down curves in tissue in the vicinity of air cavities, especially at 10 MV x-rays. These findings suggest that patients with TI-T2 glottic cancers with anterior commissure invasion may receive more effective treatment with 4 MV x-rays rather than with 6 MV and 10 MV x-rays.Tl声門癌に対して放射線治療を単独で行うのは確立している方法である。しかし,頚部は解剖学的に複雑であり,前方に薄いⅤ字形で,喉頭が気道に隣接している構造を持つので,病巣への線量はbuild-upとbuild-downの影響による線量低下が生じることが考えられる。すなわち,放射線エネルギーの選択が喉頭癌の局所的制御に影響を及ぼすと言える。この影響は,より高い放射線エネルギーでは,それに伴いより強く起きるということが基礎実験にて報告されている。また,それらの線量測定は,熱ルミネセンス線量計(TLD)のような従来の測定システムで測定されていた。しかし,空気空洞へTLD を単体 で浮かせ線量を正確に測定し評価を行うのは困難である。本研究において,我々は Gafchromic MD-55 film (Nuclear Associates, Inc.)を使用し測定した。 Gafchromic MD-55 film は,フィルムタイプ線量計でありエネルギー依存性がなく,3~100 Gyを測定可能であり,アクリル製頸部ファントムの空気組織境界面及び,空洞部に線量計を容易に精度良く配置することが可能である。また,この線量計は人体の軟部組織に近い組成である。そこで, 4, 6および10MVの各エネルギーでこの線量計を用いてエネルギーの違いによる,頸部ファントムを用いて喉頭の線量評価を行った。その結果,我々は,特に放射線エネルギー10MVで頸部ファントムにおける,前部組織-組織空洞境界面-空洞部の一連したbuild-upおよびbuild-downを線量計で評価することができた。これらの研究の結果、前交連浸潤を有するT1-T2に相当する声門癌患者は,放射線エネルギー6MVおよび10MVではなく,4MVを用いることによって,より効果的な放射線治療を行えると推測できる

    The mean-field approximation model of company's income growth

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    We introduce a mean-field type approximation for description of company's income statistics. Utilizing huge company data we show that a discrete version of Langevin equation with additive and multiplicative noises can appropriately describe the time evolution of a company's income fluctuation in statistical sense. The Zipf's law of income distribution is shown to be hold in a steady-sate widely, and country-dependence of income distribution can also be nicely implemented in our numerical simulation.Comment: 10 pages, 7 figures, submitted to Physics

    Tool Condition Monitoring with Convolutional Neural Network for Milling Tools and Turning Inserts

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    Tool wear is one of the cost drivers in the manufacturing industry because it directly affects the quality of the manufactured workpiece and production efficiency. Identifying the right time to replace the cutting tool is a challenge. If the tool is replaced too soon, the production time can be disrupted, causing unscheduled downtime. Conversely, if it is replaced too late, there will be an additional cost to replace raw materials damaged by broken tools. Therefore, researchers continue to develop tool condition monitoring (TCM) methods to analyze tool wear. A recent popular method is machine vision with convolutional neural networks (CNN). The present research aims to develop classification models that can categorize the image data of milling and turning inserts into GO (suitable for use) and NO GO (not suitable for use). Two approaches are selected for the modeling process, custom learning and transfer learning, with image data input from smartphones and microscope cameras. The experimental results show that the best model is the transfer learning approach using Inception-V3 architecture with a smartphone image. The model reaches 92.2% accuracy, hence demonstrating a relatively good performance in determining whether the tool is suitable for use or not

    A REVIEW: A MODEL of CULTURAL ASPECTS for SUSTAINABLE PRODUCT DESIGN

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    Product design stages are important to consider critically in production. Generally, product design that shall be created by designer, should consider what the customer wants and needs. Nowadays issues, product design does not only consider the “wants and needs” of user, but also how the design can be created by embedding sustainability aspects in the product. Culture is also one of the important aspects which need to be considered in product design as culture affects the way users respond to the product. This paper aims to develop a new model for design development, in which the aspects of culture are incorporated into sustainable product design. By reviewing the existing literature, the authors attempt to identify the gaps of the existing papers, which illustrate how culture affects sustainable product design. Recent papers have only shown that culture influences product design, but they do not explore sustainability and the culture aspects in product design. Due to these gaps, it is therefore important to create a model which will assist designers to elicit sustainable product design based on cultural aspects. In summary, designers need to reflect on the “wants and needs” of users. The framework presented in this paper can be integrated into designers’ and companies’ decision-making during product design development. Keywords: Model, Culture, Sustainable, Product design, Product Development

    Nitinol stenting improves primary patency of the superficial femoral artery after percutaneous transluminal angioplasty in hemodialysis patients: A propensity-matched analysis

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    BackgroundAlthough percutaneous transluminal angioplasty (PTA) has become a common therapeutic standard for peripheral artery disease (PAD), high restenosis rates in the superficial femoral artery (SFA) remain a major problem. Nitinol stent implantation is reported to reduce restenosis in SFA after PTA in the general population; however, little is known about whether the nitinol stent improves primary patency after PTA in hemodialysis patients who are at higher risk of revascularization failure. The aim of this study was to clarify the effects of nitinol stent implantation for primary patency in SFA after PTA in hemodialysis patients with PAD.MethodsEighty consecutive hemodialysis patients (167 SFA lesions) who underwent PTA with nitinol stents from January 2006 to January 2008 were compared with 64 hemodialysis patients (128 SFA lesions) who received stainless steel stents in the preceding 2 years. In the follow-up study to 2 years, incidence of restenosis, amputation, and all-cause mortality were analyzed. End points between the groups were examined with the Kaplan-Meier and log-rank methods. Prognostic values for end points were calculated by a Cox univariate analysis and Cox multivariable regression models. To statistically minimize the differences in each stent group, a propensity-matched analysis was also performed using the model including male gender, age, diabetes, hypertension, hyperlipidemia, smoking, incidence of ulcer/gangrene, and TransAtlantic Inter-Society Consensus (TASC) type C+D.ResultsThe 2-year primary patency rate was 58% in the nitinol group vs 42% in the stainless steel group (hazard ratio [HR], 0.58; 95% confidence interval [CI], 0.39-0.84; P = .0045), despite a higher prevalence of TASC C+D lesion in the nitinol group (68% vs 49%, P = .0014). In 108 lesions matched after propensity score analysis, the primary patency for 2 years was 64% in the nitinol group vs 42% in the stainless steel group (HR, 0.39; 95% CI, 0.24-0.65; P = .0003). Cox multivariate models showed nitinol stent (HR, 0.42; 95% CI, 0.25-0.73; P = .002), age (HR, 1.04; 95% CI, 1.01-1.08; P = .031), and incidence of ulcer/gangrene (HR, 2.35; 95% CI, 1.17-4.75; P = .017) were independent predictors of restenosis.ConclusionThese data suggest that nitinol stent implantation improves primary patency in SFA after PTA compared with the stainless steel stent, even in hemodialysis patients with PAD

    An integrated approach of fuzzy linguistic preference based AHP and fuzzy COPRAS for machine tool evaluation

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    Globalization of business and competitiveness in manufacturing has forced companies to improve their manufacturing facilities to respond to market requirements. Machine tool evaluation involves an essential decision using imprecise and vague information, and plays a major role to improve the productivity and flexibility in manufacturing. The aim of this study is to present an integrated approach for decision-making in machine tool selection. This paper is focused on the integration of a consistent fuzzy AHP (Analytic Hierarchy Process) and a fuzzy COmplex PRoportional ASsessment (COPRAS) for multi-attribute decision-making in selecting the most suitable machine tool. In this method, the fuzzy linguistic reference relation is integrated into AHP to handle the imprecise and vague information, and to simplify the data collection for the pair-wise comparison matrix of the AHP which determines the weights of attributes. The output of the fuzzy AHP is imported into the fuzzy COPRAS method for ranking alternatives through the closeness coefficient. Presentation of the proposed model application is provided by a numerical example based on the collection of data by questionnaire and from the literature. The results highlight the integration of the improved fuzzy AHP and the fuzzy COPRAS as a precise tool and provide effective multi-attribute decision-making for evaluating the machine tool in the uncertain environment

    Green product preferences considering cultural influences: a comparison study between Malaysia and Indonesia

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    Purpose – There is an increasing awareness among manufacturers to make production more sustainable in Southeast Asian countries such as Malaysia and Indonesia. Manufacturers are now urged to not only focus on the business profit but also concern on environment protection by producing green products. However, issues may arise regarding the preferences of customers on green products, which will vary due to the influence of cultural values. This will give an impact on the marketing of green products. The aim of this study is to identify the influence of cultural values on the green products design in Malaysia and Indonesia. Design/methodology/approach – A pretest on the survey instruments was performed to ensure the reliability and validity of the questionnaire. The collected data were statistically analyzed based on the satisfaction level, confirmatory factor analysis and structural equation modeling. Findings – The results showed that customer preferences in Malaysia were mostly influenced by uncertainty avoidance, long-term orientation and power distance, excluding collectivism and masculinity. In Indonesia, the dimension of uncertainty avoidance and long-term orientation had significant influence, whereas power distance, masculinity and collectivism dimension had no influence. Eco-label was identified as the most important factor for green products in Malaysia and having product services characteristics factor for product lifetime extension in Indonesia. Practical implications – For practices, the cultural values and preferred characteristics identified in this study provide valuable information to policymakers and businesses on what draws customers toward green products in Malaysia and Indonesia. This finding can be used as supported data for the policymakers in order to achieve sustainable development goal (SDGs) in Malaysia and Indonesia. Originality/value – The findings of this study provide valuable information for designers to design products with green characteristics that cater to the consumer market in Malaysia and Indonesia, as well as other countries which may have similar cultural traits

    Role of neurosteroid allopregnanolone on age-related differences in exercise-induced hypoalgesia in rats

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    The beneficial effects of physical activity for pain are denominated exercise-induced hypoalgesia (EIH). Here, we examined the age-related change and potential role of the neurosteroid allopregnanolone (ALLO) on EIH in rats. Adult and aged rats were randomly divided into one of three groups; non-exercise control, Low-exercise, and High-exercise. The animals in the Low- and High-exercise groups were subjected to a 10-minute treadmill workout at 40% and 80% maximum oxygen intake intensity, respectively. In the Low-exercise groups, a significant EIH response was observed in aged but not in adult rats. The pre-treatment with ALLO synthesis inhibitor finasteride, but not opioid-receptor antagonist naloxone, inhibited the Low-exercise induced EIH response in aged rats. Furthermore, the Low-exercise increased brain ALLO levels in aged animals compared with controls, which was correlated with the mechanical pain sensitivity. On the other hand, High-exercise could induce EIH response in both adult and aged animals, but it was more effective in adult rats. The pre-treatment with naloxone, but not finasteride, reduced the EIH observed after High-exercise in both adult and aged rats. Our findings demonstrated that effective EIH can be achieved even by mild-intensity exercise in aged animals via an increase of the brain ALLO levels
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