Electroconductive Polyamide 6/MWNT Nanocomposites: Effect of Nanotube Surface‐Coating by in situ Catalyzed Polymerization

Preparation and analysis of morphologic and electrical properties of high‐performance multiwalled carbon nanotube/polyamide 6 nanocomposites was achieved. The MWNTs were surface‐coated by in situ polymerization of ethylene as catalyzed directly from the nanotube surface previously treated by a highly active metallocene‐based complex. The so‐produced polyethylene‐coated MWNTs were melt‐mixed with the PA6 matrix. Pristine MWNTs were also dispersed in PA6. The in situ ethylene polymerization/coating reaction allowed the destructuring of the native bundle‐like aggregates leading to the preparation of nanocomposites with improved properties even at very low nanofiller content.

     

Synthesis and Investigation of Tryptophan–Amphotericin B Conjugates

Anchors aweigh! The synthesis of tryptophan–amphotericin B conjugates (see figure) is described. The membrane‐anchoring effect of tryptophane was thus combined with the pore‐formation effect of amphotericin B leading to high channel activity in sterol‐free liposomes.

     

PMMA/o‐MMT nanocomposites obtained using thermally stable surfactants

In the preparation of polymer/montmorillonite (MMT) nanocomposites, the commonly used compatibilizers (cations of long carbon‐chain alkyl ammonium salts) present the drawback of a poor thermal stability. During bulk processing of nanocomposites elevated temperatures are usually required and, if processing temperature is close to decomposition temperature of the surfactant, decomposition will occur altering the interface between filler and polymer. To solve this problem, organically modified MMTs with thermally stable imidazolium surfactants have been prepared. A series of nanocomposites were obtained by dispersing o‐MMT in poly(methyl methacryate) (PMMA) matrix via an in situ free radical polymerization. The nanocomposites were characterized by X‐ray diffraction, transmission electron microscopy, gel permeation chromatography, thermogravimetric analysis, dynamic mechanical analysis, and nanoindentation measurements. The results showed that nanocomposite thermal stability depended on both the kind of used surfactant and degree of exfoliation. Under the same values of molecular weight, the nanocomposites containing imidazolium cations showed a better thermal stability with respect to the nanocomposite obtained using a standard alkylammonium surfactant. Dynamic mechanical and Nanoindentation measurements showed an improvement of mechanical properties, such as modulus and hardness, with respect to pure PMMA. Solution blending treatments on these nanocomposites led to obtaining of further improvement of the thermal performance. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41393.     

专访米兰市议会都市发展和计划章程负责人卡罗·马瑟洛利(Carlo Masseroli)先生的专访

约瑟夫:米兰作为2015年世博会主办城市,您认为世博会能为米兰提供什么机会?特别是城市管理方面,政府有什么预期目标? 卡罗:米兰世博会体现了正面的发展,我们应该遵循米兰精神:在接近城市的传统和渊源的同时与国际接轨.     

Container shipping: operating system support for I/O-intensiveapplications

New I/O devices with data rates ranging from 10 to 100 Mbytes per second are becoming available for personal computers and workstations. Along with continual improvements in processor, memory, and bus technology, these devices have enabled I/O-intensive applications for desktop computing that require input, processing, and output of very large amounts of data. We focus on an important aspect of operating system support for these applications: efficient transfer of large data objects between the protection domains in which processes and devices reside. A rapidly growing class of I/O-intensive applications is multimedia computing. After we present an I/O-pipeline model, we analyze issues relevant to the design of an operating system inter-domain data-transfer facility. Then we present the design for such a facility. An I/O pipeline is a model of a dynamic computation structure consisting of a sequence of domains: an input domain followed by one or more intermediate domains, and an output domain     

Personalizing learning programs with X-Learn, an XML-based, “user-device” adaptive multi-agent system

In this paper we present X-Learn, an XML-based, multi-agent system for supporting “user-device” adaptive e-learning, i.e. e-learning activities which take into account the profile, past behaviour, preferences and needs of users, as well as the characteristics of the devices they use for these activities. X-Learn is characterized by the following features: (i) it is highly subjective, since it handles quite a rich and detailed user profile that plays a key role during the learning activities; (ii) it is dynamic and flexible, i.e. it is capable of reacting to variations in user exigencies and objectives; (iii) it is device-adaptive, since it decides the learning objects to present to the user on the basis of the device he is currently using; (iv) it is generic, i.e. it is capable of operating in a large variety of learning contexts; (v) it is XML based, since it exploits many facilities of XML technology for handling and exchanging information related to e-learning activities. The paper also reports various experimental results, as well as a comparison between X-Learn and other related e-learning management systems already presented in the literature.     

Spatial and temporal coherence of filtered thermal light

When a filter is placed in front of a double slit illuminated by a primary source of finite extent, the theory of partial coherence predicts that in general the interference fringes do not acquire unit visibility even as the passband of the filter is made arbitrarily narrow. The effect of reducing the filter bandwidth is that the visibility of the fringes tends to the modulus of the spectral degree of coherence and that more interference fringes become visible. A systematic experimental verification of these theoretical predictions is lacking so far and is provided here from the use of a highly sensitive CCD camera.     

Identification of genes regulated by interleukin-1beta in human endometrial stromal cells

Interleukin-1beta (IL-1b) is an important immune regulatory factor that in human endometrium plays a role in both menstruation and implantation in the event of pregnancy. It promotes inflammatory-like processes and also stimulates tissue remodelling. We present a cDNA microarray study documenting the major effects of IL-1beta on gene expression in stromal cells from human endometrium. Endometrial stromal cells from five normal healthy women at the mid secretory phase were cultured with or without IL-1beta at 50 and 500 pg/ml for 48 h. cDNA microarrays were used to compare the levels of gene expression in total RNA isolated from cells stimulated with IL-1beta. These cDNA arrays were produced containing 15 164 sequence-verified clones, which included genes known to be important in angiogenesis, immune modulators, apoptosis, cell signalling, extra-cellular matrix (ECM) remodelling and cell cycle regulation. Genes which were regulated by IL-1beta were identified by analysis of the microarray data using the Significance Analysis of Microarrays software package. Upregulated (n = 23) and downregulated (n = 6) different genes were observed, which changed at least 3-fold, at a false discovery rate of less than 2% (P < 0.02). Our results have identified genes regulated by IL-1beta, which are involved in leukocyte recruitment, ECM remodelling and other cellular functions. Changes in three genes, IL-8, colony-stimulating factor 2 and aldoketo reductase family 1 member 1, which were upregulated by IL-1beta, were verified using real-time PCR. Novel functions regulated by IL-1beta in endometrium, including genes involved in free radical protection, and fatty acid metabolism were also identified. These results also provide new insights into the role of IL-1beta in disorders of the endometrium, especially in implantation-related infertility and endometriosis, in which this cytokine plays a major role.