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61.
Silvia?Versari Livia?Barenghi Jack?van?Loon Silvia?BradamanteEmail author 《Microgravity science and technology》2016,28(1):19-28
Due to spaceflight, astronauts experience serious, weightlessness-induced bone loss because of an unbalanced process of bone remodeling that involves bone marrow mesenchymal stem cells (BMSCs), as well as osteoblasts, osteocytes, and osteoclasts. The effects of microgravity on osteo-cells have been extensively studied, but it is only recently that consideration has been given to the role of BMSCs. Previous researches indicated that human BMSCs cultured in simulated microgravity (sim-μg) alter their proliferation and differentiation. The spaceflight opportunities for biomedical experiments are rare and suffer from a number of operative constraints that could bias the validity of the experiment itself, but remain a unique opportunity to confirm and explain the effects due to microgravity, that are only partially activated/detectable in simulated conditions. For this reason, we carefully prepared the SCD – STEM CELLS DIFFERENTIATION experiment, selected by the European Space Agency (ESA) and now on the International Space Station (ISS). Here we present the preparatory studies performed on ground to adapt the project to the spaceflight constraints in terms of culture conditions, fixation and storage of human BMSCs in space aiming at satisfying the biological requirements mandatory to retrieve suitable samples for post-flight analyses. We expect to understand better the molecular mechanisms governing human BMSC growth and differentiation hoping to outline new countermeasures against astronaut bone loss. 相似文献
62.
Algorithmic Design of the Globe Wide-Area Location Service 总被引:2,自引:0,他引:2
63.
The effects of gap width on the transmission coefficient of vacuum-ultraviolet light through submicrometer-period, freestanding transmission gratings are reported. Results from computations and an analytical waveguide model are shown to be consistent with experimental measurements. These results show that thin gratings with narrow gaps and thick gratings with wide gaps are equally effective at eliminating 121.6-nm radiation. The thin gratings with the narrow gaps have the advantage of better attenuation of shorter-wavelength radiation than the thick gratings with the larger gaps. 相似文献
64.
Hildo J. Lamb A. van der Laarse B. M. Pluim H. P. Beyerbacht J. Doornbos E. E. van der Wall A. de Roos 《Magma (New York, N.Y.)》1998,6(2-3):168-170
4. Conclusions Diastolic LV function and myocardial HEP metabolism are impaired only when LVH is caused by permanent pressure or volume overload,
and not by a temporary increase in cardiac workload during part of the day as in elite athletes. Therefore, training-induced
and pressure/volume-overload-induced LVH seem to represent different phenotypes of LVH, possibly related to genetic reprogramming
which only occurs during permanent cardiac overload [17]. Moreover, there is an association between impaired LV diastolic
function and altered myocardial HEP metabolism in patients with hypertension and in patients with aortic valve disease. Finally
we did not find a correlation between myocardial HEP metabolism and LV mass in any of the groups studied. The latter indicates
that LVH should be regarded as an epiphenomenon to cardiac overload, and not as a primary factor causing abnormal HEP metabolism. 相似文献
65.
66.
The aim of this study was to gauge the effect of an artificially established flora, unnatural for mice, on the induction of oral candidosis in mice. Four groups of BALB/c mice were compared; conventional Candida albicans-free mice, "germ-free" mice which had been inoculated with Candida-free human saliva, germ-free mice which had been exposed to a cocktail of Streptococcus mitis, S. sobrinus and S. sanguis, and uncontaminated germ-free mice. After exposure to C. albicans via drinking water, the four groups of mice were killed and their oral cavities examined for candidal growth and oral lesions. Conventional mice yielded significantly less candidal growth and exhibited significantly fewer oral lesions than the other three groups. Candidal lesions in the two groups of contaminated germ-free mice were significantly fewer than in the uncontaminated germ-free mice. The latter exhibited extensive candidal lesions with little inflammatory infiltrate. It is concluded that mice with human oral micro-organisms have some resistance against candidal infection albeit at a reduced level, that mice with natural oral flora are highly resistant, and that germ-free mice are extremely susceptible to C. albicans infection. 相似文献
67.
ES van Waalwijk van Doorn AH Meier AW Ambergen RA Janknegt 《Canadian Metallurgical Quarterly》1996,23(3):345-371
This article elucidates the clinical applicability and state of the art of ambulatory urodynamics. Ambulatory urodynamics have evolved into practical investigations like EAC, HFM, and EAC combined with renal pelvimetry. EAC has been shown to be the method of preference if detrusor overactivity is involved. Conventional filling cystometry has proved to be an unreliable way to exclude detrusor instability. De novo instability after suspension surgery often indicates that an existing detrusor overactivity was not identified preoperatively. EAC including flowmetry has shown considerable variance in obstructive and contractility parameters in males with LUTS indicative for BPH. This raises doubt whether the clinical flow analysis is the suitable "gold standard" as advocated by the ICS. For a real break through of EAC, less complex automatic analysis is necessary. HFM is a newer method within the range of ambulatory urodynamic tests. It has not yet been completely evaluated. But, because the technique is analogous to the office flowmetry, noninvasive and very well accepted by the patients, it is expected to be widely used. This expectation is strengthened by the fact that HFM seems to show individual therapeutic efficacy of drugs, such as alpha-blockers. As a research tool to evaluate efficacy, it is far more powerful than conventional methods because of the reduction of within-patient standard deviation to about 10%. Finally, EAC combined with pelvimetry offers a promising method for the clinical evaluation of a combined dysfunction of upper and lower urinary tract. 相似文献
68.
G.-J. Meerkerk R.J.J.M. van den Eijnden I.H.A. Franken H.F.L. Garretsen 《Computers in human behavior》2010
Aim of the present study was to examine whether the personality correlates sensitivity to reward and to punishment, and impulsivity predict compulsive internet use (CIU). Furthermore, the predictive value of these personality correlates was compared to the predictive value of factors relating to psychosocial wellbeing. The results showed that particularly rash spontaneous impulsivity predicts CIU and that this personality factor is more important than psychosocial wellbeing factors. Sensitivity to reward, which is supposed to play a role in craving processes associated with substance abuse and eating disorders, could not be related to CIU. The data suggest that internet users who are characterized by an impulsive personality feature, are less able to control their use of the internet, which makes them more vulnerable to develop CIU. 相似文献
69.
B.A. Wols J.A.M.H. Hofman W.S.J. Uijttewaal L.C. Rietveld J.C. van Dijk 《Environmental Modelling & Software》2010,25(4):573-582
Computational Fluid Dynamics combined with a particle tracking technique provides valuable information concerning residence times and contact times in chemical reactors. In drinking water treatment, for example an accurate estimation of the disinfection is important to predict the microbial safety. Ozone contactors are widely used for disinfection, but the complex geometry of the system causes suboptimal hydraulics and requires optimizations of the flow. This results in a lower ozone dosage, which may reduce the formation of unwanted disinfection-by-products and the consumption of energy. To that end disinfection needs to be calculated precisely, accounting for the complex hydraulics. Several calculation methods estimating the disinfection performance of ozone contactors were evaluated using Computational Fluid Dynamics. For an accurate disinfection prediction, the full distribution of ozone exposures (CT values) is needed, only a mean CT value or residence time distribution provides insufficient information for an accurate disinfection prediction. Adjustments to the geometry of the ozone contactor that reduce the short-circuit flows resulted in an increase in disinfection capacity, whereas the mean CT value remained the same. A sensitivity analysis with respect to the kinetics was conducted. The gain in disinfection capacity obtained by optimizing the hydraulics was significant for typical values used in practice. 相似文献
70.
Marcello La Rosa Hajo A. Reijers Wil M.P. van der Aalst Remco M. Dijkman Jan Mendling Marlon Dumas Luciano García-Bañuelos 《Expert systems with applications》2011,38(6):7029-7040
Business process models are becoming available in large numbers due to their widespread use in many industrial applications such as enterprise and quality engineering projects. On the one hand, this raises a challenge as to their proper management: how can it be ensured that the proper process model is always available to the interested stakeholder? On the other hand, the richness of a large set of process models also offers opportunities, for example with respect to the re-use of existing model parts for new models. This paper describes the functionality and architecture of an advanced process model repository, named APROMORE. This tool brings together a rich set of features for the analysis, management and usage of large sets of process models, drawing from state-of-the art research in the field of process modeling. A prototype of the platform is presented in this paper, demonstrating its feasibility, as well as an outlook on the further development of APROMORE. 相似文献