A new model for the prediction of oxygen interference in hydrogen storage systems

A new model is developed to analyze oxygen interference in hydrogen storage materials. It is based on the competitive adsorption isotherm between the two gases, with the parameters fitted from molecular dynamic simulations. The model is applied to a system consisting of graphene sheets separated by different distances. For a gas-phase mixture of hydrogen (99.9%) and oxygen (0.1%) in interaction with porous graphite of 6.5 Å (optimum size) it can be observed that after 50 cycles of charging/discharging the blocking of active sites of the material by oxygen is ∼10%, due to progressive pollution of the system by oxygen. The model presented here may easily be extended to other systems of interest, involving other blocking species or adsorbent materials.     

Effect of visible light treatments on postharvest senescence of broccoli (Brassica oleracea L.)

BACKGROUND: Broccoli (Brassica oleracea L.) is a rapidly perishable vegetable crop. Several postharvest treatments have been applied in order to delay de‐greening. Since light has been shown to have an effect on pigment accumulation during development and darkness is known to induce senescence, the effect of continuous and periodic exposure to low‐intensity white light at 22 °C on postharvest senescence of broccoli heads was assayed. RESULTS: Exposure to a constant dose of 12 µmol m^?2 s^?1 was selected as the most suitable treatment and was employed for subsequent experiments. During the course of the treatments, hue and L* values as well as chlorophyll content and visual observation of florets indicated an evident delay in yellowing in treated samples compared with controls. No statistically significant differences in total protein content were found, but soluble protein content was higher in treated samples. Total and reducing sugar as well as starch levels decreased during postharvest senescence, with lower values in control samples. CONCLUSION: The results of this study indicate that storage under continuous low‐intensity light is an efficient and low‐cost treatment that delays postharvest senescence while maintaining the quality of harvested broccoli florets. Copyright © 2010 Society of Chemical Industry     

台北艺术中心

正为什么过去百年间最令人兴奋的剧场盛事总是发生在正规场所之外?建筑如何才能超越自身卑微的命运,摆脱那种限制各种可能的宿命?近年来,世界各地的演艺中心数目渐增,但不知何故,这些演艺中心似乎达成一种共识,呈现出雷同的空间组合:一座约2 000席的大型演艺厅和一个1 500席的中型剧院,再加上一个黑盒子剧场。标志性的外形掩饰以典型19世纪做法为基础的     

Comparison of extraction methods for the isolation of volatile compounds from distilled alcoholic beverages

Batch and continuous solvent extraction methods were evaluated, using an alcoholic model system, to select the best alternative for the isolation of volatile aroma compounds from distilled alcoholic beverages. Recoveries using pentane, pentane-diethyl ether (2:1) and dichloromethane were compared. Pentane extraction produced the best results, particularly by a continuous procedure for 6 h.     

Effects of the cholecystokinin agonist pentagastrin in patients with generalized anxiety disorder

OBJECTIVE: The anxiogenic and panicogenic effects of peripheral administration of the cholecystokinin-B receptor agonist pentagastrin and placebo were evaluated in patients with generalized anxiety disorder and normal comparison subjects. METHODS: Seven patients with generalized anxiety disorder and seven age- and sex-matched normal subjects received an intravenous bolus of placebo and pentagastrin. RESULTS: Panic attacks occurred in five patients with generalized anxiety disorder (71%) and in one normal subject (14%). Patients with generalized anxiety disorder were more likely to report more nonpanic anxiety than were normal subjects. CONCLUSIONS: Patients with generalized anxiety disorder appear to exhibit greater subjective sensitivity to pentagastrin than do normal subjects.     

Bending of glass fibre reinforced plastic (GFRP) plates on elastic supports

The behaviour of a fibreglass plate, subjected to a simulated hydraulic pressure and supported by a steel frame along the edges through a neoprene gasket, is investigated. The plate is analyzed theoretically as an orthotropic continuum using a direct variational technique in accordance with the Rayleigh-Ritz method. The load-deformation behaviour and the mode of failure is examined experimentally. Theoretical and experimental results are correlated empirically through Poisson’s ratio.

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Résumé On a étudié le comportement d’une plaque renforcée de fibre de verre soumise à une simulation de pression hydraulique et appuyée au bord sur un cadre d’acier par l’intermédiaire d’une garniture de néoprène. On a procédé à une étude théorique de la plaque en tant que milieu continu orthotrope, à l’aide d’une méthode variationnelle directe en accord avec la méthode Rayleigh-Ritz. On a aussi procédé à l’étude expérimentale du comportement charge-déformation et du mode de rupture. Une corrélation des résultats tant théorique qu’expérimentale a été établie empiriquement en utilisant le coefficient de Poisson.

     

Further evidence that naloxone acts as an inverse opiate agonist: implications for drug dependence and withdrawal

To test if naloxone behaved as an inverse agonist rather than as an antagonist we evaluated its responses in guinea-pig ilea with and without morphine (480 nM, 24 h). In control ilea, naloxone (100 nM) had no effect. In morphine-treated ilea, naloxone as a bolus, but not as an infusion, elicited an abstinence response. Preadministration of naloxone blocked the response to subsequent administrations. Similarly, naloxone failed to produce an abstinence response in ilea pretreated with kappa compounds (bremazocine, U50488 or xorphanol 100 nM) or with kinase inhibitors (H7 or H8 30 microM). These findings can be interpreted in the light of the two-state receptor model if naloxone behaves as an inverse agonist: Incubation with morphine increased the active state of receptors making them susceptible to the inverse agonist (naloxone); exposure to naloxone favored the inactive conformation making them insensitive to further administration of naloxone; kappa compounds behaved as antagonists preventing the response to naloxone; and kinase inhibitors interfered with the active conformation making the system insensitive to naloxone. According to this model, dependence can be viewed as an overexpression of the active receptors and withdrawal as an abrupt change from the active to the inactive state.