| 1. |
- Song, Hong-Wei, et al.
(författare)
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Thermal fatigue on pistons induced by shaped high power laser : Part II: Design of spatial intensity distribution via numerical simulation
- 2008
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Ingår i: International Journal of Heat and Mass Transfer. - : Elsevier BV. - 0017-9310 .- 1879-2189. ; 51:3-4, s. 768-778
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Tidskriftsartikel (refereegranskat)abstract
- In the laser induced thermal fatigue simulation test on pistons, the high power laser was transformed from the incident Gaussian beam into a concentric multi-circular pattern with specific intensity ratio. The spatial intensity distribution of the shaped beam, which determines the temperature field in the piston, must be designed before a diffractive optical element (DOE) can be manufactured. In this paper, a reverse method based on finite element model (FEM) was proposed to design the intensity distribution in order to simulate the thermal loadings on pistons. Temperature fields were obtained by solving a transient three-dimensional heat conduction equation with convective boundary conditions at the surfaces of the piston workpiece. The numerical model then was validated by approaching the computational results to the experimental data. During the process, some important parameters including laser absorptivity, convective heat transfer coefficient, thermal conductivity and Biot number were also validated. Then, optimization procedure was processed to find favorable spatial intensity distribution for the shaped beam, with the aid of the validated FEM. The analysis shows that the reverse method incorporated with numerical simulation can reduce design cycle and design expense efficiently. This method can serve as a kind of virtual experimental vehicle as well, which makes the thermal fatigue simulation test more controllable and predictable.
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| 2. |
- Chen, Yao, et al.
(författare)
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Laser-surface-alloyed carbon nanotubes reinforced hydroxyapatite composite coatings
- 2005
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 86:25, s. 251905-251907
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Tidskriftsartikel (refereegranskat)abstract
- Carbon-nanotube (CNT)-reinforced hydroxyapatite composite coatings have been fabricated by laser surface alloying. Microstructural observation using high-resolution transmission electron microscopy showed that a large amount of CNTs remained with their original tubular morphology, even though some CNTs reacted with titanium element in the substrate during laser irradiation. Additionally, measurements on the elastic modulus and hardness of the composite coatings indicated that the mechanical properties were affected by the amount of CNTs in the starting precursor materials. Therefore, CNT-reinforced hydroxyapatite composite is a promising coating material for high-load-bearing metal implants
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| 3. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy in higher eukaryotes
- 2008
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Ingår i: Autophagy. - : Landes Bioscience. - 1554-8627 .- 1554-8635. ; 4:2, s. 151-175
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Forskningsöversikt (refereegranskat)abstract
- Research in autophagy continues to accelerate,1 and as a result many new scientists are entering the field. Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms. Recent reviews have described the range of assays that have been used for this purpose.2,3 There are many useful and convenient methods that can be used to monitor macroautophagy in yeast, but relatively few in other model systems, and there is much confusion regarding acceptable methods to measure macroautophagy in higher eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers of autophagosomes versus those that measure flux through the autophagy pathway; thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from fully functional autophagy that includes delivery to, and degradation within, lysosomes (in most higher eukaryotes) or the vacuole (in plants and fungi). Here, we present a set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes. This set of guidelines is not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to verify an autophagic response.
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| 4. |
- Meng, Qing-Ling, et al.
(författare)
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Anatomic study of maximum intensity projection of the membranous labyrinth and the internal auditory meatus- MRI scan in 16 Chinese adults
- 2007
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Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 0001-6489 .- 1651-2251. ; 127:11, s. 1150-6
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Tidskriftsartikel (refereegranskat)abstract
- CONCLUSION: Three-dimensional reconstruction of maximum intensity projection (MIP) might document objectively, stereoscopically and directly the minute structures of the membranous labyrinth and internal auditory meatus. In this study, we establish magnetic resonance imaging (MRI) measurement criteria of the inner ear in Chinese adults.OBJECTIVE: The goal of this study was to provide an anatomic basis for otolosurgery and neurosurgery in Chinese adults.MATERIALS AND METHODS: Sixteen healthy volunteer subjects were scanned by a GE-signa 1.5T MRI scanner. All original images were transferred to an MRI workstation and all the structures of the inner ear were reconstructed, rotated at various angles and measured with an MIP program.RESULTS: Anatomic structures of the membranous labyrinth and internal auditory meatus were well demonstrated in MIP images in all volunteers. All inner ear structures including utricle, saccule, cochlear duct, internal auditory meatus and three semicircular ducts produced high intensity signals.
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| 5. |
- Xu, Min, et al.
(författare)
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Ototoxicity on cochlear nucleus neurons following systemic application of gentamicin
- 2009
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Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 1651-2251 .- 0001-6489. ; 129:7, s. 745-748
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Tidskriftsartikel (refereegranskat)abstract
- Conclusion. The gentamicin-induced pathological alteration in the cochlear nucleus is not exclusively a secondary consequence of the damage in the cochlea. Instead, the toxic effect of gentamicin on the cochlear nucleus may occur simultaneously or even earlier than that on the cochlea. Objectives. To investigate the pathological alteration of cochlear nucleus neurons in guinea pigs following systemic application of gentamicin. Materials and methods. Guinea pigs were injected with gentamicin for I day, 3 days, I week, 2 weeks, and 3 weeks, respectively. In gentamicin-treated animals, the hearing function was evaluated by measuring the auditory brainstem response (ABR). The number and cross-sectional area of substance P-positive neurons in the cochlear nucleus were also measured. Results. The threshold of ABR and the number of substance P-positive neurons in the cochlear nucleus were significantly increased after I week and 3 days of injection of gentamicin, respectively. The cross-sectional area of substance P-positive neurons in the cochlear nucleus was significantly reduced after 1-day injection of gentamicin.
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| 6. |
- Zhang, Tingting, et al.
(författare)
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Bioanalytical characterization of dioxin-like activity in sewage sludge from Beijing, China
- 2009
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 75:5, s. 649-653
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Tidskriftsartikel (refereegranskat)abstract
- In this preliminary study, the bioanalytical characterization of dioxin-like activity in the sludge of all the nine municipal sewage treatment plants from Beijing city Was Studied using chemically activated luciferase gene expression (CALUX) assay. The influence of heating period in winter, sewage and sludge treatment processes on the occurrence of dioxin-like activity was also discussed. For the use of clean coal and natural gas, heating did not have significant influence on the occurrence level of PCDD/Fs and dioxin-like-PCBs in this study. Anaerobic-aerobic-anoxic sewage treatment process did not show a good performance in the reduction of dioxin-like activity which is useful in the removal of chemical oxygen demand (COD) and nitrogen. Anaerobic digestion of sludge increased the concentration of PCDD/Fs from 30.1 to 68.3 pg CALUX-TEQ g(-1) d.w., and total dioxin-like activity from 32.2 to 69.3 pg CALUX-TEQ g(-1) d.w. This cost-effective and quick test is useful for large developing countries like China in monitoring programs to obtain baseline data about the scale of contamination caused by dioxin-like activity. It is also a useful component in the monitoring capacity building of dioxins.
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