Benzotriazole as inhibitor for copper with and without corrosion products in aqueous polyethylene glycol

Electrochemical methods, including polarization experiments and impedance spectroscopy, were used to evaluate the effectiveness of benzotriazole (BTA) in an aqueous solution of polyethylene glycol (PEG) in protecting polished archaeological copper or archaeological copper covered with corrosion products. The adsorption of PEG on the polished copper significantly limited the corrosion current. The presence of benzotriazole enhanced the protection of the polished copper, giving maximum protection at a concentration of 10^–2moll^–1 of BTA in 20 vol% PEG 400 solution. On the other hand, PEG solutions caused degradation of the corrosion products of the copper. This degradation increased with time. When BTA was added, the corrosion products were preserved and, the higher the BTA concentration, the more the corrosion current decreased. In PEG 400 solution protection of the corrosion products of the copper by BTA improved over time.     

Time course evolution of ventilatory responses to inspiratory unloading in patients

Inspiratory muscle unloading decreases ventilatory drive. In this study, we examined the time course of this effect in patients with chronic obstructive pulmonary disease receiving two modes of ventilatory support: pressure support ventilation (PSV), during which each cycle was assisted, and biphasic positive airway pressure (BIPAP), set up in such a manner that one spontaneous breath took place between two consecutive pressure-assisted breaths. The first breath following the switch from spontaneous breathing to PSV was associated with an increase in tidal volume (VT) and a drop in mean transdiaphragmatic pressure (mean Pdi) and inspiratory work (WI) performed per liter but with unchanged values of esophageal occlusion pressure at 100 ms (Pes 0.1), diaphragmatic electrical activity (EMGdi), and WI performed by breath. The same phenomena were observed for the assisted breath of BIPAP as compared with the preceding spontaneous breath. During the subsequent breaths of PSV, Pes 0.1, EMGdi, and WI performed per breath decreased progressively up to the sixth to eighth breaths, and VT returned to pre-PSV values. We conclude that in patients with chronic obstructive pulmonary disease the decrease in ventilatory drive associated with PSV takes place from the first breath onwards but requires six to eight breaths to be fully achieved. During BIPAP, as a consequence of the kinetics of the PSV-induced downregulation of ventilatory drive, assisted breaths following spontaneous breaths are characterized by an enhanced inspiratory efficiency.     

Separation of the reservoir and wave pressure and velocity from measurements at an arbitrary location in arteries

Previous studies based on measurements made in the ascending aorta have demonstrated that it can be useful to separate the arterial pressure P into a reservoir pressure P* generated by the windkessel effect and a wave pressure p generated by the arterial waves: P = P*+p. The separation in these studies was relatively straightforward since the flow into the arterial system was measured. In this study the idea is extended to measurements of pressure and velocity at sites distal to the aortic root where flow into the arterial system is not known. P* is calculated from P at an arbitrary location in a large artery by fitting the pressure fall-off in diastole to an exponential function and assuming that p is proportional to the flow into the arterial system. A local reservoir velocity U* that is proportional to P* is also defined. The separation algorithm is applied to in vivo human and canine data and to numerical data generated using a one-dimensional model of pulse wave propagation in the larger conduit arteries. The results show that the proposed algorithm is reasonably robust, allowing for the separation of the measured pressure and velocity into reservoir and wave pressures and velocities. Application to data measured simultaneously in the aorta of the dog shows that the reservoir pressure is fairly uniform along the aorta, a test of self-consistency of the assumptions leading to the algorithm. Application to data generated with a validated numerical model indicates that the parameters derived by fitting the pressure data are close to the known values which were used to generate the numerical data. Finally, application to data measured in the human thoracic aorta indicates the potential usefulness of the separation.     

High-resolution cell outline segmentation and tracking from phase-contrast microscopy images

Accurate extraction of cell outlines from microscopy images is essential for analysing the dynamics of migrating cells. Phase-contrast microscopy is one of the most common and convenient imaging modalities for observing cell motility because it does not require exogenous labelling and uses only moderate light levels with generally negligible phototoxicity effects. Automatic extraction and tracking of high-resolution cell outlines from phase-contrast images, however, is difficult due to complex and non-uniform edge intensity. We present a novel image-processing method based on refined level-set segmentation for accurate extraction of cell outlines from high-resolution phase-contrast images. The algorithm is validated on synthetic images of defined noise levels and applied to real image sequences of polarizing and persistently migrating keratocyte cells. We demonstrate that the algorithm is able to reliably reveal fine features in the cell edge dynamics.     

UML-RT到一个图形设计环境体系结构的映射

为解决把UML-RT建模模型平滑过渡到实时系统的图形化的软构件设计开发环境的设计模型，本文提出了从UML-RT的结构模型映射到该环境下的体系结构模型的高层设计的映射方法。首先介绍UML-RT结构建模的概念及笔者研制的设计环境，其次给出从UML-RT映射到该设计环境体系结构模型的具体方法、约束和限制。     

A robust information hiding scheme for tampered cover images

In this paper, we propose a robust information hiding scheme such that the secret information is restorable upon cover image tampering. The secret information is first translated into a binary image, and then the binary image is encoded into an ‘index table’ via Vector Quantisation (VQ). Without noticeable damage to image quality, the secret information codes (VQ index table of secret information) are hidden repeatedly into the cover image. Using our proposed scheme, the extracted secret codes can be almost completely restored to their original state even when the cover image has been tampered with. Experimental results show that our proposed scheme restores the secret information perfectly under many types of tampering attacks.     

Kinetics and mechanisms of the reactions of carbon dioxide with alkanolamines: a discussion concerning the cases of MDEA and DEA

A recent paper by Blauwhoff et al. (1984) has incited us to reexamine some of our previous results concerning the kinetics of reaction of CO₂ with methyldiethanolamine (MDEA). The results can be very satisfactorily interpreted if an amine-catalyzed reaction with a rate constant 3.2 ( ± 1.0) M ^?1 s ^?1 is introduced in the theoretical simulations. This value agrees fairly well with the value obtained by the authors mentioned above (4.8 M ^?1 s ^?1. The influence of the pK_A value of the amine on the theoretical simulation is also examined. The mechanism proposed by Blauwhoff et al. for the diethanolamine (DEA) reaction with CO₂ is discussed and the values of their kinetic constants are compared with our value.     

Double acting reciprocating magnetic refrigerator: first experiments

To obtain better practical knowledge of a possible refrigeration process, we have designed an experimental magnetic refrigerator which operates between 4.2 K and 1.8 K. The design performance was reached with 1/2 W capacity from two 18 cm³ magnetic parts. The static and dynamic losses, thermal efficiency, were measured.