Biphasic modulation of cell proliferation by sulforaphane at physiologically relevant exposure times in a human colon cancer cell line

Sulforaphane (SFN), a cancer chemopreventive compound derived from broccoli, is able to induce cell cycle arrest and apoptosis in various tumor cell lines. Here we show that cell growth inhibition by SFN follows a biphasic pattern: Transient exposure of 40-16 human colon carcinoma cells for up to 6 h resulted in reversible G(2)/M cell cycle arrest and cytostatic growth inhibition even at elevated concentrations, whereas a minimum continuous exposure time of 12 h was necessary for SFN to irreversibly arrest cells in G(2)/M phase and subsequently induce apoptosis. IC(50) values after 12 h of exposure followed by drug-free recovery up to 72 h (6.4-8.1 microM) were indistinguishable from those of chronic exposure for 24 to 72 h (5.4-6.6 microM). Low concentrations of SFN caused a transient decrease in glutathione (GSH) levels followed by GSH induction, which may be related to reversible G(2)/M arrest and cytostatic effects. Depletion of GSH does not seem to play a role in SFN-mediated apoptosis induction. Our data clearly contribute to a better understanding of the kinetics of antiproliferative activity of SFN.     

An experimental study of void fraction and heat transfer under upward and downward flow boiling conditions

Heat transfer coefficient and actual void fraction have been measured during upflow and downflow boiling of water in an annular channel. At the same values of pressure, mass flux, heat flux and flow quality significant difference of void fraction has been established in upflow and downflow. The upflow and downflow heat transfer coefficients did not deviate significantly from each other, if compared at identical values of pressure, mass flux, heat flux and actual void fraction.     

The effect of water temperature on the adsorption equilibrium of dissolved organic matter and atrazine on granular activated carbon

The influence of water temperature on the adsorption of natural dissolved organic matter (DOM) on activated carbon has not been investigated intensively yet. In this study, batch experiments with granular activated carbon (GAC) have been carried out at three temperatures (5 degrees C, 20 degrees C, 35 degrees C) using a humic acid model water and different types of surface water (lake, river, canal). Furthermore, the adsorption of an anthropogenic contaminant, atrazine, was quantified in the absence and presence of DOM. The results indicate a significant influence of water temperature on the adsorption equilibrium of DOM and atrazine. Contrary to expectations, DOM and atrazine adsorption in surface water tends to be increased with increasing water temperature, whereas the extent of this effect is dependent on the type and concentration of DOM. Furthermore, the temperature effect on atrazine adsorption is controlled by competition of DOM and atrazine on adsorption sites. Some assumptions are proposed and discussed for explaining the temperature effects observed in the batch studies.     

超临界流体染色技术的过去、现在和将来(一)

介绍了超临界CO2染色技术在世界范围的发展过程及其优于水染色的特点。阐述了超临界CO2对纤维性能的影响，诸如润滑效果CO2吸附、结晶、收缩和热机械性能，超临界CO2对纤维的玻璃化温度和有效温度以及对纤维损伤的影响。另一重要问题是在超临界CO2中纤维与染料之间的平衡分布和影响染料溶解性的参数。文中给出了涤纶纤维的染色步骤、设备和最佳工艺参数，然而天然纤维的染色仍是一个问题。通过浸渍溶胀剂和交联剂，或在染色前对纤维改性、添加极性共溶剂，可以提高分散染料的染色性，所有这些方法增加了工艺步骤和设备清洗，若使用有机溶剂则将大大提高机器成本，采用活性分散染料可以避免这种情况。含乙烯砜基团的染料主要适宜于羊毛和聚酰胺纤维的超临界CO2染色，而对于纤维素纤维迄今尚未开发可行的解决方法。预计在不久的将来建造工业化规模的染色设备，努力实现超临界CO2染色技术的经济效益。     

APPLICATION OF CONCENTRATED SOLAR RADIATION TO HIGH TEMPERATURE DETOXIFICATION AND RECYCLING PROCESSES OF HAZARDOUS WASTES

In many cases, hazardous wastes are subject to thermal treatment at elevated temperatures. Some types of wastes do not have a sufficient calorific value to cover the heat demand of the high temperature process. For thermal treatment of e.g. filter residues, dusts, sulfuric acid, aluminium dross, foundry sand, or waste water, supplementary energy supply is needed. The specific energy demand ranges from 0.5 to 2.5 kWh/kg (2–10 MJ/kg). An important aim of process optimisation is the reduction of (fossil) energy consumption and exhaust gas flow. Concentrated solar energy promises advantages when applied to high energy consuming waste treatment processes with regard to substitute fossil or electric energy consumption, to reduce CO₂ emissions, and exhaust gas flow. In parallel to conceptional studies, a solar-heated rotary kiln mini-plant has been designed and constructed for tests in the DLR solar furnace. The tests will give indications of boundary conditions for solar thermal treatment or conversion of selected hazardous materials.     

Tetany, spasmophilia, hyperventilation syndrome: theoretical and therapeutic synthesis

The hyperventilation syndrome (HVS), characterised by multiple somatic symptoms induced by inappropriate hyperventilation, constitutes the physiopathological manifestation of a common disorder in general medicine. As a synonym of spasmophilia or tetany, it has the advantage of offering diagnostic criteria, even though the latter are still vaguely defined. But its definition allows for objective measurements: indeed, a decrease in PCO2 during a hyperventilation provoking test and an abnormally low PCO2 rate at rest can be easily quantified. Moreover, the HVS concept offers a treatment which is both structured (respiratory reeducation, psychotherapy and pharmacology) and efficient. Yet, a number of scientific uncertainties still exist. There is no general agreement regarding the criteria which should be taken into account in a hyperventilation provoking test in order to diagnose an hyperventilation syndrome; the specificity of such a test is weak and a placebo can induce as many symptoms as can a HVS. Respiratory reeducation has good results but does not necessarily have an effect on PCO2. Some therapists see in it no more than a mechanism of relaxation and a rational explanation of frightening symptoms. This has led some authors to reject the term "hyperventilation syndrome" and to prefer the expression "chronic hyperventilation of unknown origin".     

Structural engineering of nanoporous anodic aluminium oxide by pulse anodization of aluminium

Nanoporous anodic aluminium oxide has traditionally been made in one of two ways: mild anodization or hard anodization. The first method produces self-ordered pore structures, but it is slow and only works for a narrow range of processing conditions; the second method, which is widely used in the aluminium industry, is faster, but it produces films with disordered pore structures. Here we report a novel approach termed "pulse anodization" that combines the advantages of the mild and hard anodization processes. By designing the pulse sequences it is possible to control both the composition and pore structure of the anodic aluminium oxide films while maintaining high throughput. We use pulse anodization to delaminate a single as-prepared anodic film into a stack of well-defined nanoporous alumina membrane sheets, and also to fabricate novel three-dimensional nanostructures.