Bacterial carbonate precipitation improves the durability of cementitious materials

Shortcomings of conventional surface treatments have drawn the attention to alternative techniques for the improvement of the durability of concrete. This paper reports the effects of bacterial carbonate precipitation (biodeposition) on the durability of mortar specimens with different porosity. Durability was assessed from the permeation properties and resistance towards degradation processes. The surface deposition of calcium carbonate crystals decreased the water absorption with 65 to 90% depending on the porosity of the specimens. As a consequence, the carbonation rate and chloride migration decreased by about 25-30% and 10-40% respectively. An increased resistance towards freezing and thawing was also noticed. The results obtained with the biodeposition treatment were similar as those obtained with conventional surface treatments.     

Intercomparison campaign of spectroradiometers for a correct estimation of solar spectral irradiance: results and potential impact on photovoltaic devices calibration

This paper describes the results of an intercomparison of spectroradiometers for global and direct normal incidence irradiance in the visible and near‐infrared spectral regions together with an assessment of the impact these results may have on the estimation of the short‐circuit current (I_SC) calibration of photovoltaic devices and on the spectral mismatch calculation. The intercomparison was conducted in the framework of the European project Apollon with the additional participation of external partners from the Italian project for the long‐term monitoring of solar radiation for photovoltaics. Six institutions and six spectroradiometer systems, representing different technologies and manufacturers, were involved. Prior to the intercomparison, all participating partners calibrated their own instrument(s) according to their usual procedures in order to verify the entire measuring and traceability chain. The difference in measured spectra shape and amplitude showed to have an impact on I_SC calculation of less than 3% and less than 6% for single‐junction and multi‐junction devices, respectively. When only the shape of the spectra is considered, the spectral mismatch ranges from 1.7% to 4.7% depending on the spectral response of the device. Copyright © 2013 John Wiley & Sons, Ltd.     

Response to cognitive therapy in depression: The role of maladaptive beliefs and personality disorders.

This study examined whether personality disorder status and beliefs that characterize personality disorders affect response to cognitive therapy. In a naturalistic study, 162 depressed outpatients with and without a personality disorder were followed over the course of cognitive therapy. As would be hypothesized by cognitive theory (A. T. Beck & A. Freeman, 1990), it was not personality disorder status but rather maladaptive avoidant and paranoid beliefs that predicted variance in outcome. However, pre- to posttherapy comparisons suggested that although patients with or without comorbidity respond comparably to "real-world" cognitive therapy, they report more severe depressive symptomatology at intake and more residual symptoms at termination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Limited-Dose Electron Microscopy Reveals the Crystallinity of Fibrous C–S–H Phases

Using electron diffraction, we demonstrate that the fibrous calcium–silicate–hydrates (C–S–H) of tricalciumsilicate (C₃S) hydration possess a crystalline structure. The crystalline nature was revealed by limiting the electron dose, which is common in electron microscopy of biomacromolecules. Compared with room temperature, the fading of the electron diffraction patterns at −175°C occurs at an electron dose that is about one order of magnitude higher. A combination of low-dose and cryo-protection methods offers the possibility to investigate the structures of water-containing cement phases by high-resolution electron microscopy in a close-to-native state.     

Repair of Protein Radicals by Antioxidants

In vivo, proteins are the main targets for radicals and other reactive species. Their reactions result in formation of amino acid radicals on the protein surface that often yield tryptophan and tyrosyl radicals or, in the presence of O₂, protein peroxyl radicals and hydroperoxides. All these species may propagate damage to biomolecules. Low molecular weight antioxidants, such as ascorbate, urate, and glutathione, are part of the defense system and function by repairing damaged proteins. We briefly review the existing knowledge about protein and amino acid radicals and their repair by antioxidants, including results of our investigations. The main question addressed is whether the antioxidants ascorbate, urate, and glutathione are able to repair amino acid radicals in model compounds and in proteins in vitro by pulse radiolysis. We show that ascorbate and urate repair tryptophan and tyrosyl radicals efficiently and inhibit proton-coupled electron transfer from tyrosine residues to tryptophan radicals in a number of proteins. In contrast, repair by glutathione is much slower. Ascorbate also rapidly reduces the peroxyl radicals of the N-acetylamide derivatives of glycine, alanine, and proline, whereas glutathione reduces peroxyl radicals in lysozyme. In vivo urate, ascorbate, and glutathione may prevent biological damage or, at least, reduce its rate, because they: (a) repair tryptophan and tyrosyl radicals in proteins and (b) reduce protein peroxyl radicals to the corresponding protein hydroperoxides. Most likely, in vivo, ascorbate and glutathione do not inhibit the reaction of C-centered amino acid radicals with O₂. Glutathione is less efficient that urate and ascorbate in repairing protein radicals; furthermore, the resulting glutathiyl radical is harmful. Ascorbate may be the more important repair agent in cells and tissues characterized by high ascorbate concentrations, such as the lens and brain; urate may be mainly responsible for repair in tissue compartments with higher urate concentrations, such as in plasma and saliva.     

The development of novel organotin anti-tumor drugs: structure and activity

An overview of the development of anti-tumor organotin derivatives in selected classes of compounds is presented and discussed. High to very high in vitro activity has been found, sometimes equaling that of doxorubicin. Solubility in water is an important issue, dominating the in vivo testing of compounds with promising in vitro properties. The cytotoxicity of the compounds was increased by the presence of a bulky group, an active substituent or one or more polar substituents. Polar substituents may also improve the water solubility. Although organotin derivatives constitute a separate class of compounds, the comparison with cisplatin is inevitable. Among the observed toxicities, neurotoxicity, known from platinum cytostatics, and gastrointestinal toxicity, typical for many oncology drugs, have been detected. Further research to develop novel, useful organotin anti-tumor compounds should be carried out.     

斯芬克司住宅，赫依曾，荷兰

5座斯芬克司住宅的每一栋各容纳了14间为了充分利用地段和阳光而组织起来的公寓。建筑的体量在背向水面的方向被斜切，从而使得从湖岸和公寓所能看到的湖景不被阻隔。当人在从楼里往上走时，公寓的数目逐层递减。结果产生了一种斯芬克司式的轮廓，面向太阳的屋顶退台置于这个神话中的怪兽的脊背上。每个建筑体量的雨篷设计是不同的，从而使其独特的头部产生一种韵律感——从连接新开拓地和现有大陆的stichtse桥上看去的一条激动人心的天际线。