615 research outputs found

    自記式「健康チェック票THI」による健康に及ぼす喫煙の影響評価-地方都市と大都市の学生間の比較-

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    キャンパスが群馬県内(Iキャンパス)、東京都内(Tキャンパス)および愛知県内(Nキャンパス)にあるA私立大学の学生347人(男子121人、女子226人)を対象に、喫煙が健康に及ぼす影響について、自記式「健康チェック票THI」によって評価した。対象学生の喫煙率は全国平均と比較して、Iキャンパスの男子学生がやや高かったことを除くと、ほぼ同程度であった。健康状態は1.2万人の標準グループから得られた尺度得点の分布をもとに、パーセンタイル値で評価した。喫煙者の健康状態は非喫煙者と比較して、身体面およびメンタル面の両方において劣る傾向がみられ、特に、女子学生の方が男子学生より顕著であった。さらに、Iキャンパスの学生より、TキャンパスやNキャンパスの学生の方が、メンタル面の症状レベルが高い傾向が認められた。これらの結果は、喫煙が身体面の健康状態に悪影響を及ぼすことを確認するとともに、その影響は地方都市より大都会で学ぶ学生に強く出やすい可能性を示している

    heat exchanger design and optimization by using genetic algorithm for externally fired micro turbine

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    Abstract In this study, a new configuration where syngas produced by downdraft gasifier is feed directly in an externally fired air turbine is discussed. Attention was posed towards the critical component of this configuration: the heat exchanger. To achieve acceptable electrical efficiencies, high temperature of the air at the inlet turbine section was imposed. A code for heat exchanger design was built by using Matlab®, while the geometrical optimization was performed by using modeFRONTIER® by imposing a multi-objective function to maximize the overall heat transfer coefficient and minimize both costs and pressure drops across the equipment

    Flame dynamics in the lift-off region of diesel jets

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    In this work, the large eddy simulation (LES) technique is employed to computationally model a lifted jet flame at conditions representative of those encountered in diesel engines. An unsteady flamelet progress variable (UFPV) model is used for turbulence/chemistry interactions. In the model, a look-up table of reaction source terms is generated as a function of mixture fraction Z, stoichiometric scalar dissipation rate χst, and progress variable Cst by solving the unsteady flamelet equations. In the present study, the progress variable is defined based on the sum of the major combustion products. A 37-species reduced chemical reaction mechanism for n-heptane is used to generate the UFPV libraries. The results show that ignition initiates at multiple points in the mixing layer around the jet, towards the edges of the jet, where the mixture fraction is rich, and the strain rates are within the ignition limits. These ignition kernels grow in time and merge to form a continuous flame front. Lift-off height is determined by the minimum axial distance from the orifice below whichthe local scalar dissipation rate does not favor ignition.Muhsin M. Ameen, Vinicio Magi, John Abrahamhttp://cfe.uwa.edu.au/news/acs2013http://www.anz-combustioninstitute.org

    Water-Soluble Organic Components in Aerosols Associated with Savanna Fires in Southern Africa: Identification, Evolution, and Distribution

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    During the SAFARI 2000 field campaign, both smoke aerosols from savanna fires and haze aerosols in the boundary layer and in the free troposphere were collected from an aircraft in southern Africa. These aerosol samples were analyzed for their water-soluble chemical components, particularly the organic species. A novel technique, electrospray ionization-ion trap mass spectrometry, was used concurrently with an ion chromatography system to analyze for carbohydrate species. Seven carbohydrates, seven organic acids, five metallic elements, and three inorganic anions were identified and quantified. On the average, these 22 species comprised 36% and 27% of the total aerosol mass in haze and smoke aerosols, respectively. For the smoke aerosols, levoglucosan was the most abundant carbohydrate species, while gluconic acid was tentatively identified as the most abundant organic acid. The mass abundance and possible source of each class of identified species are discussed, along with their possible formation pathways. The combustion phase of a fire had an impact on the chemical composition of the emitted aerosols. Secondary formation of sulfate, nitrate, levoglucosan, and several organic acids occurred during the initial aging of smoke aerosols. It is likely that under certain conditions, some carbohydrate species in smoke aerosols, such as levoglucosan, were converted to organic acids during upward transport

    Scintillating fiber devices for particle therapy applications

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    Particle Therapy (PT) is a radiation therapy technique in which solid tumors are treated with charged ions and exploits the achievable highly localized dose delivery, allowing to spare healthy tissues and organs at risk. The development of a range monitoring technique to be used on-line, during the treatment, capable to reach millimetric precision is considered one of the important steps towards an optimization of the PT efficacy and of the treatment quality. To this aim, charged secondary particles produced in the nuclear interactions between the beam particles and the patient tissues can be exploited. Besides charged secondaries, also neutrons are produced in nuclear interactions. The secondary neutron component might cause an undesired and not negligible dose deposition far away from the tumor region, enhancing the risk of secondary malignant neoplasms that can develop even years after the treatment. An accurate neutron characterization (flux, energy and emission profile) is hence needed for a better evaluation of long-term complications. In this contribution two tracker detectors, both based on scintillating fibers, are presented. The first one, named Dose Profiler (DP), is planned to be used as a beam range monitor in PT treatments with heavy ion beams, exploiting the charged secondary fragments production. The DP is currently under development within the INSIDE (Innovative Solutions for In-beam DosimEtry in hadrontherapy) project. The second one is dedicated to the measurement of the fast and ultrafast neutron component produced in PT treatments, in the framework of the MONDO (MOnitor for Neutron Dose in hadrOntherapy) project. Results of the first calibration tests performed at the Trento Protontherapy center and at CNAO (Italy) are reported, as well as simulation studies

    Genome-wide analysis of nuclear magnetic resonance metabolites revealed parent-of-origin effect on triglycerides in medium very low-density lipoprotein in PTPRD gene

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    The aim of the study was to explore the parent-of-origin effects (POEs) on a range of human nuclear magnetic resonance metabolites. Materials & methods: We search for POEs in 14,815 unrelated individuals from Estonian and Finnish cohorts using POE method for the genotype data imputed with 1000 G reference panel and 82 nuclear magnetic resonance metabolites. Results: Meta-analysis revealed the evidence of POE for the variant rs1412727 in PTPRD gene for the metabolite: triglycerides in medium very low-density lipoprotein. No POEs were detected for genetic variants that were previously known to have main effect on circulating metabolites. Conclusion: We demonstrated possibility to detect POEs for human metabolites, but the POEs are weak, and therefore it is hard to detect those using currently available sample sizes.Peer reviewe

    Aerosol Properties and Chemical Apportionment of Aerosol Optical Depth at Locations off the U.S. East Coast in July and August 2001

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    Airborne in situ measurements of vertical profiles of the aerosol light scattering coefficient, light absorption coefficient, and single scattering albedo (ω0) are presented for locations off the East Coast of the United States in July–August 2001. The profiles were obtained in relatively clean air, dominated by airflows that had passed over Canada and the Atlantic Ocean. Comparisons of aerosol optical depths (AODs) at 550 nm derived from airborne in situ and sun-photometer measurements agree, on average, to within 0.034 ± 0.021. A frequency distribution of ω0 measured in the atmospheric boundary layer off the coast yields an average value of ω0 = 0.96 ± 0.03 at 550 nm. Values for the mass scattering efficiencies of sulfate and total carbon (organic and black carbon) derived from a multiple linear regression are 6.0 ± 1.0 m2 (g SO=4)−1 and 2.6 ± 0.9 m2 (g C)−1, respectively. Measurements of sulfate and total carbon mass concentrations are used to estimate the contributions of these two major components of the submicron aerosol to the AOD. Mean percentage contributions to the AOD from sulfate, total carbon, condensed water, and absorbing aerosols are 38% ± 8%, 26% ± 9%, 32% ± 9%, and 4% ± 2%, respectively. The sensitivity of the above results to the assumed values of the hygroscopic growth factors for the particles are examined and it is found that, although the AOD derived from the in situ measurements can vary by as much as 20%, the average value of ω0 is not changed significantly. The results are compared with those obtained in the same region in 1996 under more polluted conditions

    Role of [18F]FDG PET/CT in the management of G1 gastro-entero-pancreatic neuroendocrine tumors

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    Purpose: Since the role of [18F]FDG PET/CT in low-grade gastroenteropancreatic (GEP) neuroendocrine neoplasia (NET) is not well established, this study was aimed to evaluate the role of [18F]FDG PET/CT in grade 1 (G1) GEP-NETs. Methods: This is a retrospective study including patients with G1 GEP-NETs who underwent [18F]FDG PET/CT. Results: 55 patients were evaluated, including 24 (43.6%) with pancreatic NETs and 31 (56.4%) with gastrointestinal NETs. At the time of diagnosis, 28 (51%) patients had metastatic disease, and 50 (91%) patients were positive by 68-Ga sstr PET/CT. Overall, 27 patients (49%) had positive findings on [18F]FDG PET/CT. Following [18F]FDG PET/CT, therapeutic management was modified in 29 (52.7%) patients. Progression-free survival was longer in patients with negative [18F]FDG PET/CT compared with positive [18F]FDG PET/CT (median PFS was not reached and 24 months, respectively, p = 0.04). This significance was particularly evident in the pancreatic group (p = 0.008). Conclusions: Despite having low proliferative activity, approximately half of GEP-NETs G1 showed positive [18F]FDG PET/CT, with a corresponding negative impact on patients’ clinical outcomes. These data are in favor of a more “open” attitude toward the potential use of [18F]FDG PET/CT in the diagnostic work-up of G1 GEP-NETs, which may be used in selected cases to detect those at higher risk for an unfavorable disease course
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