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  • 2005-2009  (3)
  • 1
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 121-123 (Mar. 2007), p. 243-246 
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: We present a prototype of thermal interface material (TIM) by incorporating aligned carbonnanotube arrays (CNA) into polydimethylsiloxane (PDMS). The morphology of CNA wasmaintained by adopting in-situ injection molding method, and the nanotube-polymer composite filmwas obtained by curing the PDMS at room temperature. We applied steady-state methods to measurethe thermal conductivity of this kind of nanocomposite. Comparing to the pure PDMS, the thermalconductivity of the composite was greatly increased, which can be attributed to the thermalconducting passages formed by vertical aligned carbon nanotubes from one side of the film to theother. We also managed to improve the thermal conducting performance of the composite byevaporating a 1-μm-thick aluminum film on the top of a raw CNA, which serves as a heat currentcollector to decrease the thermal contact resistance. The experiment results suggest these kinds ofcomposites have broad application prospect for thermal management in the future
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Journal of periodontal research 40 (2005), S. 0 
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Objectives:  Reactive oxygen species (ROS) are implicated in the destruction of the periodontium during inflammatory periodontal diseases. The imbalance in oxidant/antioxidant activity may be a key factor in the damaging effects of ROS. This study aimed to determine the lipid peroxidation levels in gingival crevicular fluid and saliva, and glutathione (GSH) and glutathione peroxidase (GPx) in saliva in patients with chronic periodontitis.Methods:  Gingival crevicular fluid and saliva were collected from 13 patients and 9 healthy control subjects during the preliminary study, and from 21 patients during the subsequent study. Lipid peroxidation level, GSH level and GPx activity were determined by spectrophotometric assay.Results:  The preliminary study found that when comparing patients to healthy controls, the gingival crevicular fluid samples produced the following results, respectively: higher lipid peroxidation concentration (µm) (by sites: 167.55 vs. 53.71, p 〈 0.0001; by subjects: 151.99 vs. 50.66, p 〈 0.005) and total amount (pmol) (by sites: 93.02 vs. 8.47, p 〈 0.0001, by subjects: 80.44 vs. 7.84, p 〈 0.0005). In saliva samples, lower GSH concentration (µm) (373.04 vs. 606.67, p 〈 0.05), higher lipid peroxidation concentration (µm) (0.66 vs. 0.13, p 〈 0.0005), and no difference in GPx activity were found in patients than in those of healthy controls. The subsequent study showed statistically significant (p 〈 0.05) improvement of clinical periodontal parameters (plaque index, gingival index, probing attachment level, probing pocket depth and gingival crevicular fluid volume), decreases in gingival crevicular fluid lipid peroxidation levels (concentration and total amount) at the sites after the completion of phase 1 periodontal treatment. Similarly, the periodontal treatment resulted in a significant decrease of lipid peroxidation concentrations (p 〈 0.05), increase in GSH concentration (p 〈 0.001), and no change in GPx activity in saliva samples.Conclusion:  The increased levels of lipid peroxidation may play a role in the inflammation and destruction of the periodontium in periodontitis.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 381-382 (June 2008), p. 101-104 
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Experiments are carried out on a femtosecond laser micromachining system with thewavelength 775nm. The ablated patterns on Si (100) and Si (111) surfaces affected by femtosecondpulse laser parameters are presented. The periodic structure termed ripples on silicon surface isinvestigated. Two kinds of ripples on the ablated surface are observed by SEM. The whole ablationregion indicates the ablated field of all amount of laser energy. The ablation region forms twocircular areas. The cross section image of the ablated region is showed which is cut by FIB in theorthogonal direction of the line of the center ripples. The depth of ripples is measured. Adjusted thelaser fluence as about 0.3~0.33J/cm2 and the pulse number as changeable from 1 to 50, the formingprocess of the ripples is observed and studied by AFM. Another experiment is done that thewave-plates are inserted into the space between the objective and sample, the result of the directionof ripples changed with the wave-plates of 1/2 or 1/4 is reviewed
    Type of Medium: Electronic Resource
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