An Approach to Combining Results From Multiple Methods Motivated by the ISO GUM

The problem of determining a consensus value and its uncertainty from the results of multiple methods or laboratories is discussed. Desirable criteria of a solution are presented. A solution motivated by the ISO Guide to the Expression of Uncertainty in Measurement (ISO GUM) is introduced and applied in a detailed worked example. A Bayesian hierarchical model motivated by the proposed solution is presented and compared to the solution.     

Screening of phenylalanine ammonia lyase in plant tissues,and retention of activity during dehydration

BACKGROUND: Oral therapy with phenylalanine ammonia lyase (PAL), naturally encapsulated in plant cells, may provide a potential alternative treatment for hyperphenylalaninemic patients, including those with phenylketonuria. Therefore different sources of plant tissue were investigated for PAL activity. RESULTS: Enzyme activity was highest in grain seedlings, with maximal enzyme activity in 7‐day‐old red spring wheat (Triticum aestivum L.) seedlings. The PAL activities of leaves and roots/endosperm of wheat seedlings were 11.90 ± 2.64 and 6.48 ± 1.59 µmol h^?1 g^?1 dry weight respectively. Three PAL‐related polypeptides with molecular weights of 74, 83 and 103 kDa were identified in wheat seedling leaf tissues, while only the 74 kDa polypeptide was detected in root/endosperm tissues. Dehydration was investigated as a method of concentrating PAL in wheat seedlings. Freeze‐drying was found to retain the most PAL activity (>90% recovery on a dry weight basis) compared with air drying and vacuum microwave drying for both leaf and root/endosperm samples. CONCLUSION: This study has led to a better understanding of PAL activity and stability in plant tissues and provides the basis for developing a natural plant preparation as a dietary supplement for the treatment of hyperphenylalaninemia. Copyright © 2007 Society of Chemical Industry     

Feeling is Believing: Using a Force‐Feedback Joystick to Teach Dynamic Systems

As an innovative approach to providing physical demonstrations in the engineering classroom, we present the haptic paddle: a low‐cost, single‐axis force‐feedback joystick. Using the paddle in the laboratory component of an undergraduate course on dynamic systems, students not only learned to model and analyze dynamic systems, but they also felt the effects of phenomena such as viscous damping, stiffness, and inertia. By interacting with virtual environments using their sense of touch, students improved their understanding of dynamic systems, modeling and control. In addition, the paddles added entertainment and excitement to the course. In this paper, we describe the purpose and design of the haptic paddle, show examples of how the paddle was integrated into the course, and present the results of preliminary student evaluations.     

数字电源管理为价格敏感型应用提供可调速度控制

引言 许多厨房与车库电器、电动工具以及其他小家电中使用的传统通用电动机一般都不能精确地控制速度.电动机只能关或开.通过数字电源管理实现精确可调速度控制的方法具有显著优点,如耗电量降低、安全性提高、工具寿命延长、更易用和操作控制改善.这种方法还最大程度低减少了电器开关时产生的可导致电路断开的电涌.历史上,对于许多消费类电器而言,实现智能电机控制的主要障碍是成本.     

ATP potentiates interleukin-1 beta-induced MMP-9 expression in mesangial cells via recruitment of the ELAV protein HuR

Renal mesangial cells express high levels of matrix metalloproteinase 9 (MMP-9) in response to inflammatory cytokines such as interleukin (IL)-1 beta. We demonstrate here that the stable ATP analog adenosine 5'-O-(thiotriphosphate) (ATP gamma S) potently amplifies the cytokine-induced gelatinolytic content of mesangial cells mainly by an increase in the MMP-9 steady-state mRNA level. A Luciferase reporter gene containing 1.3 kb of the MMP-9 5'-promoter region showed weak responses to ATP gamma S but conferred a strong ATP-dependent increase in Luciferase activity when under the additional control of the 3'-untranslated region of MMP-9. By in vitro degradation assay and actinomycin D experiments we found that ATP gamma S potently delayed the decay of MMP-9 mRNA. Gel-shift and supershift assays demonstrated that three AU-rich elements (AREs) present in the 3'-untranslated region of MMP-9 are constitutively bound by complexes containing the mRNA stabilizing factor HuR. The RNA binding of these complexes was markedly increased by ATP gamma S. Mutation of each ARE element strongly impaired the RNA binding of the HuR containing complexes. Reporter gene assays revealed that mutation of one ARE did not affect the stimulatory effects by ATP gamma S, but mutation of all three ARE motifs caused a loss of ATP-dependent increase in luciferase activity without affecting IL-1 beta-inducibility. By confocal microscopy we demonstrate that ATP gamma S increased the nucleo cytoplasmic shuttling of HuR and caused an increase in the cytosolic HuR level as shown by cell fractionation experiments. Together, our results indicate that the amplification of MMP-9 expression by extracellular ATP is triggered through mechanisms that likely involve a HuR-dependent rise in MMP-9 mRNA stability.     

The effect of particle reinforcement on the creep behavior of single-phase aluminum

The effect of TiC particle reinforcement on the creep behavior of Al (99.8) and Al-1.5Mg is investigated in the temperature range of 150 °C to 250 °C. The dislocation structure developed during creep is characterized in these materials. The addition of TiC increases creep resistance in both alloys. In pure aluminum, the presence of 15 vol pct TiC leads to a factor of 400 to 40,000 increase in creep resistance. The creep strengthening observed in Al/TiC/15_p is substantially greater than the direct strengthening predicted by continuum models. Traditional methods for explaining creep strengthening in particle-reinforced materials(e.g., threshold stress, constant structure, and dislocation density) are unable to account for the increase in creep resistance. The creep hardening rate(h) is found to be 100 times higher in Al/TiC/15_p, than in unreinforced Al. When incorporated into a recovery creep model, this increase inh can explain the reduction in creep rate in Al/TiC/15_p. Particle reinforcement affects creep hardening, and thus creep rate, by altering the equilibrium dislocation substructure that forms during steady-state creep. The nonequilibrium structure generates internal stresses which lower the rate of dislocation glide. The strengthening observed by adding TiC to Al-1.5Mg is much smaller than that found in the pure aluminum materials and is consistent with the amount of strengthening predicted by continuum models. These results show that while both direct (continuum) and indirect strengthening occur in particle-reinforced aluminum alloys, the ratio of indirect to direct strengthening is strongly influenced by the operative matrix strengthening mechanisms. This article is based on a presentation made in the symposium entitled “Creep and Fatigue in Metal Matrix Composites” at the 1994 TMS/ASM Spring meeting, held February 28–March 3, 1994, in San Francisco, California, under the auspices of the Joint TMS-SMD/ASM-MSD Composite Materials Committee.     

Pervasive information — the key to ‘true’ mobility

Since Weiser’s vision in 1991 for ubiquitous (also called pervasive) computing there has been little tangible progress towards it. However, over time the communications industry has begun to erode many of the hardware barriers to this vision. Even so, the utopia of pervasive computing remains out of reach, primarily as a result of the continued fixation with devices and connectivity as a way to realise mobility. However, it could be argued that users ultimately require access to information or content irrespective of the devices and connectivity around them. Consequently, pervasive information is seen as the key to true user mobility. This paper will introduce a potential secure pervasive information architecture that fits Weiser’s vision, and position it with respect to a sub-set of current contenders for future systems from both academia and the telecommunications industry, and highlight their strengths and weaknesses.     

Tissue-derived macromolecules and markers of inflammation in serum in early rheumatoid arthritis: relationship to development of joint destruction in hands and feet

We have previously shown that serum concentrations of cartilage oligomeric matrix protein (COMP) are increased early in rheumatoid arthritis (RA) patients who subsequently develop advanced large-joint destruction. A prognostic value for joint damage of serum concentrations of hyaluronan (HA) is also suggested by previous studies. In contrast, serum concentrations of bone sialoprotein (BSP) have not been useful for identifying patients with progressive large-joint destruction. In the present study, we have examined the hypothesis that serum concentrations of these tissue-derived markers are of prognostic value in RA for the development of radiographically detectable joint damage in hands and feet. Serum concentrations of COMP, HA and BSP were quantified in samples obtained from 62 patients within the first year after onset of RA and were related to the development of radiographically detectable damage in these joints after 5 yr. Neither the serum concentrations of COMP nor of BSP at inclusion predicted joint damage in hands and feet after 5 yr, and the concentration of these proteins did not change over the 5 yr period. However, the serum concentration of HA at inclusion correlated with the radiographic score at the 5 yr follow-up (r = 0.425, P < 0.01), but was not a better predictor in this respect than the erythrocyte sedimentation rate or C-reactive protein levels at inclusion. Thus, serum concentrations of the three studied tissue-derived macromolecules were in this study not useful for identifying patients prone to small-joint destruction.